Archive of Past Facts of the Day:

April 5, 2008
The Jules Verne Automated Transfer Vehicle is an unmanned European cargo spacecraft, launched on 9 March 2008, on a mission to supply the International Space Station with propellant, water, air, and dry cargo. Jules Verne will also be used to reboost the station into a higher orbit. Because it is the first ATV, the spacecraft underwent three weeks of testing before it's rendezvous with the ISS on 3 April 2008. After spending up to six months docked at the station, Jules Verne will undock and de-orbit to a destructive re-entry over the Pacific Ocean. This was the first non-Russian fully automated space docking operation (the very first fully automated space docking was done in 1967 by Cosmos 186 and Cosmos 188). Source

April 4, 2008
The Malay kite is a model of tailless kite. First introduced to the West in a New York newspaper article from October 1894, the Malay kite was used for recreation for centuries before this in parts of the Far East. The Malay is similar in design to the standard Eddy design. The precise design of the kite consists of two flexible cross sticks, diverging at right angles, to form a lozenge-like shape. The horizontal stick is preferably slightly longer than the vertical one. Once they have been bound together, a string or cord is tightened around the resulting lozenge. The design is then enveloped in the kite material, such as paper. This particular design, when correctly executed, allows the wind to carry the kite to great heights, despite its lack of any kind of tail. Source

April 3, 2008
Martin Cooper (born December 26, 1928 in Chicago) is considered the father of the mobile phone (as distinct from the car phone), inventor of the first portable handset and the first person to make a call on a portable cell phone on April 3, 1973, to the bewilderment of passers-by in a New York City street. Cooper later revealed that watching Captain Kirk talking in his communicator on the television show Star Trek inspired him to research the mobile phone. Cooper's Law is the term used for his observation that the number of radio frequency conversations which can be concurrently conducted in a given area has doubled every 30 months since Marconi's spark gap transmitter. Source

April 2, 2008
David Dunbar Buick was a Scottish born American inventor best known for founding the Buick Motor Company. He moved to Detroit from Scotland at the age of two when his parents emigrated to the United States. Among his many innovations are a lawn sprinkler, and a method for permanently coating cast iron with vitreous enamel, used in the production of "white" bathtubs. Later, Buick produced the, at the time revolutionary, "Valve-in-Head" overhead valve internal combustion engine. This method of engine construction produces a much more powerful engine than the rival side valve engine design which all other manufacturers used at the time. Most modern engine designs are derivatives of Buick's invention. Source

April 1, 2008
The term outrunner refers to a type of brushless motor primarily used in electrically propelled, radio-controlled model aircraft. This type of motor spins its outer shell around its windings, much like motors found in ordinary CD-ROM computer drives. In fact, CD-ROM motors are frequently rewound into brushless outrunner motors for small park flyer aircraft. Parts to aid in converting CD-ROM motors to aircraft use are commercially available. Outrunners spin much slower than their inrunner couterparts with their more traditional layout (though still considerably faster than ferrite motors) while producing far more torque. This makes an outrunner an excellent choice for directly driving electric aircraft propellers since they eliminate the extra weight and complexity of a gearbox. Source

March 31, 2008
April Fools' Day is a notable day celebrated in many countries on April 1. The day is marked by the commission of hoaxes and other practical jokes of varying sophistication on friends, enemies and neighbors, or sending them on fools' errands, the aim of which is to embarrass the gullible. The origins of this custom are unclear, but it is likely a relic of the once common festivities held on the vernal equinox, which began on the 25th of March, old New Year's Day, and ended on the 2nd of April. Though the 1st of April appears to have been observed as a general festival in Great Britain in antiquity, it was apparently not until the beginning of the 18th century that the making of April-fools was a common custom. In Scotland the custom was known as "hunting the gowk," i.e. the cuckoo, and April-fools were "April-gowks," the cuckoo being a term of contempt, as it is in many countries. One of the earliest connections of the day with fools is Chaucer's story the Nun's Priest's Tale (c.1400), which concerns two fools and takes place "thritty dayes and two" from the beginning of March, which is April 1. Source

March 30, 2008
Parisian inventor édouard-Léon Scott de Martinville created the “phonautograph” – a device that scratched sound waves onto a sheet of paper blackened by the smoke of an oil lamp. Though Scott never intended the recordings made with his device to be played back, a group of researchers has done so by scanning the markings on the paper into a computer which has reconstructed the original sounds. From Scott's original work, they have succeeded in playing a sound recording of a human voice made April 9, 1860 – 17 years before Thomas Edison invented the phonograph. Roughly ten seconds in length, the recording is of a person singing “Au clair de la lune, Pierrot répondit” – a snippet from a French folksong. Source

March 28, 2008
Earth Hour is an international event that asks households and businesses to turn off their lights and non-essential electrical appliances for one hour on the evening of 29 March at 8 pm local time until 9 pm to promote electricity conservation and thus lower carbon emissions. It is promoted by World Wide Fund for Nature Australia, an environmental lobby group, and the Sydney Morning Herald. The first Earth Hour was held in Sydney, Australia between 7:30 pm and 8:30 pm on 31 March 2007. The 2007 Earth Hour is estimated to have cut Sydney's mains electricity consumption by between 2.1% and 10.2% for that hour, with as many as 2.2 million people taking part. Source

March 27, 2008
Flash memory is computer memory that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products. Flash memory is non-volatile, which means that it does not need power to maintain the information stored in the chip. In addition, flash memory offers fast read access times and better kinetic shock resistance than hard disks. These characteristics explain the popularity of flash memory in portable devices. Flash memory was invented by Dr. Fujio Masuoka while working for Toshiba in 1984. According to Toshiba, the name "flash" was suggested by Dr. Masuoka's colleague, Mr. Shoji Ariizumi, because the erasure process of the memory contents reminded him of a flash of a camera. Intel introduced the first commercial flash chip in 1988. Source

March 26, 2008
Bradyll is an early steam locomotive built by Timothy Hackworth at his Soho Works in Shildon in 1840. She is the oldest surviving locomotive with an 0-6-0 wheel arrangement. Bradyll was obsolete by the 1870s, and in 1875 she was converted into a snowplough. By World War Two, she had been withdrawn from this duty, but escaped the scrap drive as she was on an isolated piece of track. After the war, she was placed at the works gates to the Philadelphia Iron Works as a "gate guardian" and regularly painted with a tar-based paint, which helped to preserve her. Bradyll has never been restored, and is probably unique in this respect. Bradyll is currently on display at Locomotion, Shildon. She will be conserved, but no restoration will take place to return her to an "as built" appearance. Source

March 25, 2008
A thermal transfer printer is a technology commonly used in label printers that has a print-head containing many small resistive heating pins that on contact, depending on the type of thermal transfer printer, melt wax-based ink onto ordinary paper or burn dots onto special coated paper. Label Printers use a wide range of label materials, including paper and synthetic polymer materials. Some designs also use heat to transfer ink from a ribbon onto the label for a permanent print. Source

March 24, 2008
Johannes Gutenberg (c. 1400 – 1468) was a German goldsmith and printer, who is credited with inventing movable type printing in Europe (c. 1439) and mechanical printing globally. His major work, the Gutenberg Bible, also known as the 42-line bible, has been acclaimed for its high aesthetic and technical quality. Among the specific contributions to printing that are attributed to Gutenberg are the design of metal movable type, the invention of a process for making such type in quantity, the use of oil-based ink, and the use of a wooden printing press similar to the screw olive and wine presses of the period. Source

March 23, 2008
A shot tower is a tower designed for the production of shot balls used for projectiles in firearms. In a shot tower, molten lead is dropped through a copper sieve high up in the tower. The liquid lead solidifies as it falls and by surface tension forms tiny spherical balls. The partially cooled balls are caught at the floor of the tower in a water-filled basin. To make larger shot sizes, a copper sieve with larger holes is used. However, the maximum size is limited by the height of the tower, because larger shot sizes must fall further to cool. Shot towers were replaced by the "wind tower" method by the end of the 19th century, which used a blast of cold air to dramatically shorten the drop necessary. Today the Bliemeister method uses molten lead dropped a very short distance (quarter inch, rather than 150-300 feet as a shot tower might use) into hot water or another hot coolant, and rolled along an incline underwater to round the balls. Source

March 22, 2008
An optical printer is a device consisting of one or more film projectors mechanically linked to a movie camera. It allows filmmakers to re-photograph one or more strips of film. The optical printer is used for making special effects for motion pictures, or for copying and restoring old film material. Common optical effects include fade outs and fade ins, dissolves, slow motion, fast motion, and matte work. More complicated work can involve dozens of elements, all combined into a single scene. The first, simple optical printers were constructed early in the 1920s. Linwood G. Dunn expanded the concept in the 1930s, and the development continued well into the 1980s, when the printers were controlled with minicomputers. Prime examples of optical printing work include the matte work in 2001: A Space Odyssey and Star Wars. Source

March 21, 2008
The tuba is the largest and lowest pitched of brass instruments. Sound is produced by vibrating or "buzzing" the lips into a large cupped mouthpiece. It is one of the most recent additions to the modern symphony orchestra, first appearing in the mid-19th century, when it largely replaced the ophicleide. Tubas are found in various pitches, most commonly in F, E-flat, CC, or BB-flat. The main tube of a BB-flat tuba is approximately 18 feet long, while that of a CC tuba is 16 feet, of an E-flat tuba 13 feet, and of an F tuba 12 feet (not including any valve branches). Tubas are considered to be conical in shape as the bore of their tubing steadily increases in diameter along its length, from the mouthpiece to the bell. Source

March 20, 2008
Stoccareddo is a secluded village in the Italian Alps that was, until the late 20th century, very isolated. It is known for its 400 villagers with great health who tend to be able to consume fatty foods without the consequences of strokes and heart attacks. Because of its location, the villagers were not able to mingle with any outside citizens. Almost all of Stoccareddo's villagers have the surname Baù, and are all from the same family. Although many Baùs have children with other Baùs, they tend to marry more distant relatives and not first cousins, which can cause genetic defects. Most of Stoccareddo's villagers have phenomenally good health, despite their diet of fried cheeses and other unhealthy Italian delicacies. According to The Independent, 38% of Stoccareddo's men have high cholesterol, as opposed to the Italian average of 21%. However, about 23% of Italian men have low levels of HDL (good cholesterol) as opposed to 5.4% of men in Stoccareddo. Also, hypertension affects about 33% of Italian men, but only 6.5% of Stoccareddo men. Source

March 19, 2008
The Chicago Tunnel Company built a unique freight tunnel network under downtown Chicago. Construction of the system began in 1899, and by 1906  there was a tunnel under almost every street of downtown Chicago. Six feet wide by seven and a half high (1.8 by 2.3 metres) tunnels were officially constructed to house only telephone cables, but the Illinois Tunnel Company also secretly installed two foot gauge railroad tracks in the tunnels. Through the years, the system expanded to approximately 60 miles (97 km) of track, with 149 four wheeled electric locomotives, and over 3000 freight cars in service. Trucks stole away significant amounts of business, and the Chicago Tunnel Company was declared bankrupt in 1956, the network was closed and abandoned in the summer of 1959. These tunnels are currently used for utilities such as cable television, and were involved in the Chicago Flood of 1991. Source

March 18, 2008
Arthur C. Clarke (16 December 1917 – 19 March 2008) was a British science fiction author, inventor, and futurist, most famous for his novel 2001: A Space Odyssey, and for collaborating with director Stanley Kubrick on the film of the same name. Clarke's work is marked by an optimistic view of science empowering mankind's exploration of the solar system. Clarke's most important scientific contribution may be in propagating the idea that geostationary satellites would be ideal telecommunications relays. He described this concept in a paper titled "Extra-Terrestrial Relays — Can Rocket Stations Give Worldwide Radio Coverage?", published in Wireless World in October 1945. The geostationary orbit is now sometimes known as the Clarke Orbit or the Clarke Belt in his honour. Source

March 17, 2008
The Post Office Railway, also known as Mail Rail, was a narrow-gauge driverless private underground railway in London built by the Post Office to move mail between sorting offices. Inspired by the Chicago Tunnel Company, it was in operation from 1927 until 2003. It ran east–west from Paddington Head District Sorting Office in the west to the Eastern Head District Sorting Office at Whitechapel in the east, a distance of 6.5 miles (10.5 km). It had eight stations, the largest of which was located underneath Mount Pleasant, but by 2003 only three stations remained in use because the sorting offices above the other stations had been relocated. Despite a report by the Greater London Authority in support of the continued use of Mail Rail, the system was taken out of use in the early hours of 31 May 2003. Source

March 16, 2008
Botnet is a jargon term for a collection of software robots, or bots, which run autonomously and automatically. They run on groups of "zombie" computers controlled remotely. While the term "botnet" can be used to refer to any group of bots, it generally refers to compromised computers infected with worms, Trojan horses, or backdoors. The majority of these computers are running Microsoft Windows operating systems, but other operating systems can be affected. A botnet's originator (aka "bot herder") can control the group remotely, usually through a means such as IRC, and usually for nefarious purposes. Source

March 15, 2008
A Mercury coulometer is a device that measures the amount of electricity (in coulombs) consumed or produced in a circuit. It is based on the electrochemical processes of oxidation/reduction, and typically consists of two reservoirs connected by a thin graduated capillary. Each of the reservoirs have an electrode immersed into a drop of mercury. Another small drop of mercury is inserted into the capillary. When the current is turned on, it will initiate dissolution of the metallic mercury on the one side of the drop in the capillary and deposition on the other side of the same drop. This drop starts to move. Because of the 100% efficiency of the deposition/dissolution of the mercury under the current influence, mass or volume of this small drop will be a constant and its movement will be lineary correlated with the passed charge. If you change direction of the current, the drop starts move in opposite direction. Sensitivity of this type of coulometers depends on the diameter of the capillary. Source

March 14, 2008
A geothermal exchange heat pump, also known as a ground source heat pump, is a heat pump that uses the Earth as either a heat source, when operating in heating mode, or a heat sink, when operating in cooling mode. Heat pumps move heat from a source to a sink. With ground source heat pumps, the source is the ground, and the sink is the house or other object to which the heat is being transferred. They use the same basic system as a refrigerator, which transfers heat from the inside of the refrigerator (the 'source') to the outside (the 'sink'). Source

March 13, 2008
Dextre, also known as the Special Purpose Dexterous Manipulator, is a two armed robot launched March 11, 2008 to the International Space Station. Designed primarily for servicing tasks on the exterior of the space station, it is flexible and strong enough to accomplish many other kinds of tasks in space, and will perform some activities that would otherwise require spacewalks. Dextre resembles a headless torso fitted with two extremely agile, 3m long arms. The 3.5m long body pivots at the "waist". The two arms have seven offset joints, built-in grasping jaws, a retractable socket drive, a monochrome TV camera, lights, and an umbilical connector that can provide power, data, and video, to/from a payload. Source

March 12, 2008
The Deccan Traps are a large igneous province located on the Deccan Plateau of west-central India and one of the largest volcanic features on Earth. They consist of multiple layers of solidified flood basalt that together are more than 2,000 meters thick and cover an area of 500,000 km². The Deccan Traps formed between 60 and 68 million years ago, at the end of the Cretaceous period. The gases released in the process may have played a role in the Cretaceous–Tertiary extinction event, which included the extinction of the dinosaurs. The release of volcanic gases during the formation of the traps may have caused massive global warming. Some data point to an average rise in temperature of 8 °C (14 °F) over half a million years. Source

March 11, 2008
A roof garden is any garden on the roof of a building. Humans have grown plants atop structures since antiquity. Besides the decorative benefit, roof plantings may provide food, temperature control, architectural enhancement, and recreational opportunities. Available gardening areas in cities are often seriously lacking, which is likely the key impetus for many roof gardens. The garden may be on the roof of an autonomous building which takes care of its own water and waste. Hydroponics and other alternative methods can expand the possibilities of roof top gardening by reducing, for example, the need for soil or its tremendous weight. Plantings in containers are used extensively in roof top gardens. One high-profile example of a building with a roof garden is Chicago City Hall. Source

March 10, 2008
The Bay of Fundy is a bay on the Atlantic coast of North America, on the northeast end of the Gulf of Maine between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine. The Bay of Fundy is known for its high tidal range and the bay is contested as having the highest vertical tidal range in the world. Folklore in the Mi'kmaq First Nation claims that the tides in the Bay of Fundy are caused by a giant whale splashing in the water. Oceanographers attribute it to tidal resonance resulting from a coincidence of timing: the time it takes a large wave to go from the mouth of the bay to the opposite end and back is the same as the time from one high tide to the next. During the 12.4 hour period, 115 billion tonnes of water traverses in and out of the bay twice. Source

March 9, 2008
The North Pacific Gyre is a swirling vortex of ocean currents comprising most of the northern Pacific Ocean. It is located between the equator and 50º N latitude and occupies an area of approximately ten million square miles. The center of the North Pacific Gyre is relatively stationary region of the Pacific Ocean and the circular rotation around it draws waste material in. This has led to the accumulation of flotsam and other debris in huge floating 'clouds' of waste. While historically this debris has biodegraded, the gyre is now accumulating vast quantities of plastic and marine debris. Rather than biodegrading, plastic photodegrades, disintegrating in the ocean into smaller and smaller pieces. These pieces, still polymers, eventually become individual molecules, which are still not easily digested. The floating particles also resemble zooplankton, which can lead to them being consumed by jellyfish, thus entering the ocean food chain. In samples taken from the gyre in 2001, the mass of plastic exceeded that of zooplankton (the dominant animalian life in the area) by a factor of six. Some sources have reported that there is a "floating continent" of debris that is roughly twice the size of Texas. Source

March 8, 2008
The original Los Angeles Aqueduct was designed by William Mulholland to deliver water from the Owens River to the city of Los Angeles. The project began in 1905 with a budget of $24.5 million. With 5,000 workers employed in its construction, the Los Angeles Aqueduct was finished in 1913. It consisted of 223 miles of 12-foot steel pipe, 120 miles of railroad track, 2 hydroelectric plants, 170 miles of power lines, 240 miles of telephone line, a cement plant, and 500 miles of roads. The aqueduct used gravity to carry the water, so it was relatively autonomous and cost-efficient. The construction of the Los Angeles Aqueduct effectively ended the development of the Owens Valley as a farming community and devastated the ecosystem of Owens Lake. The catastrophic failure of the St. Francis Dam in 1928 that flooded the Santa Clarita Valley and parts of Ventura County and an incident of sabotage by displaced Owens Valley farmers a few years previously marred the early days of the aqueduct, however the system has worked well otherwise, and is still in use today. Source

March 7, 2008
Frank Lloyd Wright (1867 – 1959) was an American architect, interior designer, writer, educator, and philosopher from Oak Park, Illinois, who designed more than 1,000 projects, of which more than 500 resulted in completed works. He promoted organic architecture, originated the Prairie School of architecture, and developed the concept of the Usonian home. His work includes original and innovative examples of many different building types, including offices, churches, schools, hotels, and museums. Wright also often designed many of the interior elements of his buildings, such as the furniture and stained glass. Source

March 6, 2008
Eugène Belgrand (1810–1878) was a French engineer who made significant contributions to the modernization of the Parisian sewer system during the 19th century rebuilding of Paris. Much of Belgrand's work remains in use today. Prior to 1850, the water system in Paris was inadequate for its growing population. Waste water was discharged into the Seine, a primary source of the critically limited supply of drinking water. Belgrand designed tunnels intended to be clean, easily accessible, and substantially larger than the previous Parisian underground. Under his guidance, Paris's sewer system expanded fourfold between 1852 and 1869. He also addressed the city's fresh water needs, constructing a system of aqueducts that nearly doubled the amount of water available per person per day and quadrupled the number of homes with running water. Belgrand's projects remain one of the most extensive urban sewer systems in the world and served as a transitional phase leading to modern wastewater processing. Source

March 5, 2008
An air brake is a conveyance braking system applied by means of compressed air. Modern trains rely upon a fail-safe air brake system that is based upon a design patented by George Westinghouse on March 5, 1872. In the air brake's simplest form, called the straight air system, compressed air pushes on a piston in a cylinder. The piston is connected through mechanical linkage to brake shoes that can rub on the train wheels, using the resulting friction to slow the train. Westinghouse invented a system wherein each piece of railroad rolling stock was equipped with an air reservoir and a triple valve, also known as a control valve. The triple valve performs two functions: it applies the brakes and releases them. Under the Westinghouse system, therefore, brakes are applied by reducing train line pressure and released by increasing train line pressure. The Westinghouse system is thus fail safe—any failure in the train line, including a separation ("break-in-two") of the train, will cause a loss of train line pressure, causing the brakes to be applied and bringing the train to a stop. Source

March 4, 2008
The Messier objects are a set of astronomical objects catalogued by French astronomer Charles Messier in his catalogue of Nebulae and Star Clusters first published in 1774. The original motivation behind the catalogue was that Messier was a comet hunter, and was frustrated by objects which resembled but were not comets. He therefore compiled a list of these objects. The total list consists of 110 objects, ranging from M1 to M110. The final catalogue was published in 1781 and printed in the Connaissance des Temps in 1784. Many of these objects are still known by their Messier number. Source

March 3, 2008
Joseph Priestley (1733 – 1804) was a British theologian, Dissenting clergyman, natural philosopher, educator, and political theorist who published over 150 works. During his lifetime, Priestley's considerable scientific reputation rested on his invention of soda water, his writings on electricity, and his discovery of several "airs" (gases), the most famous being what Priestley dubbed "dephlogisticated air" or what is now known as oxygen. However, Priestley's determination to defend phlogiston theory and to reject what would become the Chemical Revolution eventually left him isolated within the scientific community. Priestley, who strongly believed in the free and open exchange of ideas, advocated toleration and equal rights for religious Dissenters, which also led him to help found Unitarianism in England. The controversial nature of Priestley's publications combined with his outspoken support of the French Revolution aroused public and governmental suspicion; he was eventually forced to flee to the United States after a mob burned down his home and church in 1791. Source

March 2, 2008
The Milliarium Aureum (or Golden Milestone) was a gilded bronze monument erected by the Emperor Augustus Caesar near the temple of Saturn in the central Forum of Ancient Rome. All roads were considered to begin from this monument and all distances in the Roman Empire were measured relative to that point. On it were listed all the major cities in the empire and distances to them. Today, only the base of the milestone still exists. Source

March 1, 2008
The MS Stolt Surf was a chemical tanker ship that achieved a measure of infamy when she was struck and damaged by a rogue wave. The Stolt Surf departed Singapore in October 1977, on a routine voyage across the Pacific Ocean to Portland, Oregon. En route, she encountered at least one 'freak wave', which towered above the tanker, reaching a height of at least 22 metres and rising above the height of the bridge deck. Chief engineer Karsten Petersen took a number of pictures of the storm, which recorded several features distinct to freak waves, namely deep troughs and waves so tall that they break. Despite the severe damage, there were no serious injuries, and only one sailor was subsequently hospitalised. Linear models had predicted that such extreme waves were extremely rare, to the extent that a 30 metre crest to trough wave would occur only once every 10,000 years. The proof gathered by the Stolt Surf joined a growing body of evidence that the linear model did not adequately explain all of the types of waves that could be encountered. Source

February 29, 2008
An auto rickshaw is a vehicle for hire that is one of the chief modes of transport in India as well as many other countries. It is a motorized version of the traditional rickshaw, a small two- or three-wheeled cart pulled by a person, and the velotaxi. An auto rickshaw, or simply just rickshaw, is generally characterized by a tin/iron body resting on three small wheels (one in front, two on the rear), a small cabin for the driver (called an auto-wallah in some areas) in the front and seating for three in the rear. Autos are generally fitted with a scooter version of a two-stroke engine with a handlebar for control instead of a steering wheel, effectively making them a three-wheeler scooter carrying passengers on the rear seat. Source

February 28, 2008
A leap year (or intercalary year) is a year containing one or more extra days (or, in case of lunisolar calendars, an extra month) in order to keep the calendar year synchronised with the astronomical or seasonal year. For example, February would have 29 days in a leap year instead of the usual 28. Seasons and astronomical events do not repeat at an exact number of full days, so a calendar which had the same number of days in each year would over time drift with respect to the event it was supposed to track. By occasionally inserting (or intercalating) an additional day or month into the year, the drift can be corrected. A year which is not a leap year is called a common year. Source

February 27, 2008
A bascule bridge is a moveable bridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic. Bascule is a French term for seesaw and balance, and bascule bridges operate along the same principle. They are the most common type of movable bridge in existence because they open quickly and require relatively little energy to operate. Nikolaevsky Bridge across the Neva in Saint Petersburg was the first large bascule bridge, opened in 1850. Many bascule type bridges can be found crossing the Chicago River, including the Michigan Avenue bridge seen in the movie The Blues Brothers. Source

February 26, 2008
Gwiazda Polski (The Star of Poland) was a balloon, which was planned to reach the stratosphere, thus beating the 1930s high-altitude world record, established on November 11, 1935 by Albert William Stevens and Orvil A. Anderson, in the Explorer II balloon. Stevens and Anderson ascended to the altitude of 22,066 m (72,395 feet), the Poles wanted to reach the altitude of 30 kilometers. The balloon was 120 meters, capacity of the bag was 124,700 m³ and weight 1500 kg. As costs of this undertaking were high, a special stamp, depicting the balloon was issued by the Polish Mail. Captain Zbigniew Burzynski and Doctor Konstanty Jodko-Narkiewicz, attempted the stratospheric flight in The Star of Poland on October 14, 1938 in the Tatra Mountains, but the balloon caught fire when it was less than 100 feet above the ground. According to witnesses, a spark appeared on the top of the bag and quickly enveloped the balloon. It burned very fast. Fortunately, the gondola was spared and no one was injured. Source

February 25, 2008
An eddy current (also known as Foucault current) is an electrical phenomenon discovered by French physicist Léon Foucault in 1851. It is caused when a moving (or changing) magnetic field intersects a conductor, or vice-versa. The relative motion causes a circulating flow of electrons, or current, within the conductor. These circulating eddies of current create electromagnets with magnetic fields that oppose the effect of the applied magnetic field (see Lenz's law). The stronger the applied magnetic field, or greater the electrical conductivity of the conductor, or greater the relative velocity of motion, the greater the currents developed and the greater the opposing field. Source

February 24, 2008
A funicular railway is a type of self-contained cable railway in which a cable attached to a pair of tram-like vehicles on rails moves them up and down a very steep slope, the ascending and descending vehicles counterbalancing each other. The word is from the Latin funiculus, a diminutive of funis, "rope". The basic principle of funicular operation is that two cars are attached to each other by a cable, which runs through a pulley at the top of the incline. Counterbalancing of the two cars, with one ascending and one descending the slope — especially when transporting similar loads, such as passengers — minimizes the energy needed to lift the ascending car. The earliest such railways were water-driven, allowing barge traffic of canals to ascend and descend steep hills. An early example were the three inclined planes on the Tyrone Canal in County Tyrone that was in use as early as 1777. They were used primarily in the early 19th century, especially during the height of the canal-building era in the 1830s in the United States. Source

February 23, 2008
A people mover is a fully automated, grade-separated mass transit system. The term is generally used only to describe systems serving relatively small areas such as airports, downtown districts or theme parks, but is sometimes applied to considerably more complex automated systems. The term was originally applied to two different systems, developed roughly at the same time. One was the Skybus, an automated mass transit system produced by the Westinghouse Electric Corporation beginning in 1964. The other, which was called PeopleMover or Goodyear PeopleMover, was an attraction sponsored by the Goodyear Tire and Rubber Company which opened at Disneyland in 1967. Now, however, the term "people mover" is generic, and may use technologies such as monorail, duorail, automated guideway transit or maglev. Propulsion may involve conventional on-board electric motors, linear motors or cable traction. Source

February 22, 2008
A dashpot is a mechanical device, a damper which resists motion via viscous friction. The resulting force is proportional to the velocity, but acts in the opposite direction, slowing the motion and absorbing energy. It is commonly used in conjunction with a spring (which acts to resist displacement). A dashpot is a common component in a door closer to prevent it from slamming shut. Consumer electronics often use dashpots where it is undesirable for a media access door or control panel to suddenly pop open when the door latch is released. Dashpots are commonly used in dampers and shock absorbers. The hydraulic cylinder in an automobile shock absorber is a dashpot. Source

February 21, 2008
The Edwin Smith Papyrus is an Ancient Egyptian textbook on trauma surgery, written in hieratic around the 17th century BCE, but thought to be based on material from a thousand years earlier. It is the world's earliest known example of medical literature. It describes anatomical observations and the examination, diagnosis, treatment, and prognosis of numerous injuries in exquisite detail. The treatments are quite rational, and magic is resorted to in only one case. Among the treatments are closing wounds with sutures, preventing and curing infection with honey and mouldy bread, and stopping bleeding with raw meat. Immobilisation was often advised for head and spinal cord injuries, when there was little else anybody could do. Source

February 20, 2008
The SS Leonardo da Vinci was an ocean liner built in 1960 by Ansaldo Shipyards, Italy for the Italian Line as a replacement for their SS Andrea Doria that had been lost in 1956. In 1976 the Leonardo da Vinci became the last Italian Line passenger liner to be used in service across the North Atlantic. Between 1977 and 1978 she was used as a cruise ship by Italia Crociere, but was laid up from 1978 onwards until 1982 when she was scrapped. Named after the famous Italian inventor Leonardo da Vinci, the ship featured numerous technological innovations. Particularly unusual were provisions for conversion to run on nuclear power, though the plan was never implemented. Source

February 19, 2008
The Mauch Chunk and Summit Hill Switchback Railroad was a 9-mile (14-km) gravity railroad in Pennsylvania constructed in 1827. It sent anthracite from company mines up at Summit Hill to the company's coal chutes in Mauch Chunk on the Lehigh River. The return trip was handled by mules, who then rode the trains downhill. Thus, downhill cars covered the trip in just half an hour, while the uphill trip took four hours. The trains were sometimes up to fourteen cars long, hauling 25 short tons (23,000 kg) of anthracite. The railroad was only the second in the United States (and the first coal road), and it was scenic and exciting to ride downhill, so it became a tourist attraction, and started occasionally carrying passengers. Soon, coal would only be handled in the morning, with passenger service taking over the afternoon. This recreational use would gain importance, become the sole purpose of the railroad, and inspire the development of the roller coaster. Source

February 18, 2008
NorNed is a 580-kilometre (360 mi) long HVDC submarine power cable between Norway and the Netherlands, which will interconnect both countries' electricity grids. Currently under construction, the NorNed cable is planned as a bipolar HVDC link with a voltage of 450 kV and a capacity of at least 700 MW. When completed the NorNed cable will be the longest submarine power cable in the world. In submarine power cables, a DC system may use the ground and seawater as a return path for current. The length of undersea AC cables is restricted by the capacitance between the active conductors and the surrounding metallic shield. If the cable were to be made long enough, the reactive power produced by an AC cable would take up the entire current carrying capacity of the conductor, so no usable power would be transmitted. Therefore, for transmission of large amounts of electric power through long submarine cables, direct current (DC) is preferred over AC, because DC cables require no reactive power. As well, for three phase AC-cables three conductors are necessary, while for DC only 1 or 2 conductors are required. Source

February 17, 2008
SS Meteor is the unique surviving ship of the experimental "whaleback" design. The design, created by Scottish captain Alexander McDougall (1845-1923), enabled her to carry a maximum amount of cargo with a minimum of draft. His design has been likened to a cigar with bent up ends. The bow and stern were nearly identical in shape, both conoidal, truncated to end in a relatively small disc. Instead of the traditional hard line at the gunwale, the hull curved over to meet the deck. When fully loaded, only the curved portion of the hull remained above the water, giving the vessel its “whaleback” appearance. Instead of crashing into the sides of the hull, waves would simply wash over the deck. The Meteor was built in 1896 in Superior, Wisconsin and, with a number of modifications, sailed until 1969. The Meteor is the last extant example of an experimental class of lakers, other than wrecks, such as the Thomas Wilson. However, the Meteor is at present poorly maintained; her hull is rusting and the interiors are in serious disrepair. Due to her condition, she was named one of the 10 most endangered historical properties by the Wisconsin Trust for Historic Preservation. Source

February 16, 2008
The NZR RM class Thomas Transmission railcar was an experimental electro-mechanical railcar operated by the New Zealand Railways Department. It was introduced to service in 1916 and therefore was one of the earliest railcars to operate in New Zealand. The railcar employed the Thomas system of transmission, built by Thomas Transmission Ltd of England. They also supplied the underframe and bogies, and J. Tylor and Sons of London provided the railcar's 150 kW V8 petrol engine. Power from the engine was transmitted to the leading bogie mechanically and to the rear bogie electrically by current produced by a generator within the engine. When engine revolutions passed a certain level, the electrical system was cut and used for battery charging while special clutches and gears allowed the engine to mechanically drive both bogies. Source

February 15, 2008
The covering of the Senne was one of the defining events in the history of Brussels. The Senne was historically the main waterway of Brussels, though it became more polluted and less navigable as the city grew. By the second half of the 19th century, it had become a serious health hazard and was filled with pollution, garbage and decaying organic matter. In 1865 a design was selected to cover over the river and build a series of grand boulevards and public buildings. The project's completion in 1871 allowed urban renewal and the construction of the modern buildings and the boulevards which are central to downtown Brussels today. Purification of the waste water from the Brussels-Capital Region was not completed until March of 2007, when two purification stations were built, thus finally cleaning the Senne after centuries of problems. Source

February 14, 2008
Thermionic emission is the flow of charge carriers from a surface or over some other kind of electrical potential barrier, caused by thermal vibrational energy overcoming the electrostatic forces restraining the charge carriers. The charge carriers can be electrons or ions, and are sometimes referred to as "thermions". The total charge of the emitted carriers will be equal in magnitude and opposite in sign to the charge left in the emitting region. The most classical example of thermionic emission is the emission of electrons from a hot metal cathode into a vacuum, such as in a vacuum tube used for radio or television. Source

February 13, 2008
Sir John Ambrose Fleming (1849 - 1945) was an English electrical engineer and physicist. In November 1904, he invented and patented the two-electrode vacuum-tube rectifier, which he called the oscillation valve. It was also called a thermionic valve, vacuum diode, kenotron, thermionic tube, or Fleming valve. The Supreme Court of the United States later invalidated the patent because of an improper disclaimer and, additionally, maintained the technology in the patent was known art when filed. This invention is often considered to have been the beginning of electronics, for this was the first vacuum tube. Fleming's diode was used in radio receivers and radars for many decades afterwards, until it was superseded by solid state electronic technology more than 50 years later. Source

February 12, 2008
Centralia is a borough in Pennsylvania. Its population has dwindled from over 1,000 residents in 1981 to 9 in 2007, as a result of a 46-year-old mine fire burning beneath the borough. The fire likely began on May 27, 1962 when commercial haulers serving the borough put hot ashes into the dump. The ashes ignited a fire in the lower depths of the garbage and eventually spread through a hole in the rock pit into the abandoned coal mines beneath Centralia. In 1979, locals became aware of the scale of the problem when a gas-station owner inserted a stick into one of his underground tanks to check the fuel level. When he withdrew it he was shocked to discover that the temperature of the gasoline in the tank was 172 degrees Fahrenheit (77.8°C). Today a handful of occupied homes remain in Centralia. Most of the buildings have been razed, and at casual glance the area now appears to be a meadow with several paved streets through it, and some areas are being filled with new-growth forest. Source

February 11, 2008
Deep Blue was a chess-playing computer developed by IBM. On 11 May 1997, the machine won a six-game match by two wins to one with three draws against world champion Garry Kasparov. The system derived its playing strength mainly out of brute force computing power. It was a massively parallel, 30-node, RS/6000, SP-based computer system enhanced with 480 special purpose VLSI chess chips. Its chess playing program was written in C and ran under the AIX operating system. It was capable of evaluating 200 million positions per second. Deep Blue was the 259th most powerful supercomputer at the time, capable of calculating 11.38 gigaflops. Source

February 10, 2008
The J37 was the first turbojet engine designed in the United States. It was not considered important at first and development was allowed to languish. The design was later converted to a turboprop, the T35, and still later sold to Wright Aeronautical, where it saw some interest for use on what would become the B-52, before that design moved to jet power. The J37 and T35 was built to the extent of testbed examples, but never entered production. In 1933 Nathan C. Price of Doble Steam Motors, a manufacturer of steam engines for cars and other uses, started working on a steam turbine for aircraft use. The engine featured a centrifugal compressor that fed air to a combustion chamber, which in turn fed steam into a turbine before exiting through a nozzle, powering both the compressor and a propeller. The engine was fitted to a test aircraft in early 1934, where it demonstrated performance on par with existing piston engines, but maintaining power to higher altitudes due to the compressor. Work on the design ended in 1936 after Doble found little interest in the design from aircraft manufacturers or the Army. Source

February 9, 2008
A globe is a three-dimensional scale model of Earth or other spheroid celestial body such as a planet, star, or moon. It may also refer to a spherical representation of the celestial sphere, showing the apparent positions of the stars in the sky. The earliest known globe was constructed by the scholar Crates of Mallus in Cilicia (now modern-day Turkey) around 150 BC. The oldest existing terrestrial globe was made by Martin Behaim in Germany, in 1474. Source

February 8, 2008
The Boeing 747 is the first wide-body commercial airliner ever produced. The original version of the 747 was two and a half times the size of the Boeing 707 and the aircraft is so massive that the wingspan is longer than the Wright Brother's first flight. First flown commercially in 1970, it held the passenger capacity record for 37 years. The 747-400, the latest version in service, is among the fastest airliners in service with a high-subsonic cruise speed of Mach 0.85 (567 mph or 913 km/h). It has an intercontinental range of 7,260 nautical miles (8,350 mi or 13,450 km). The 747-400 passenger version can accommodate up to 524 passengers. The 747 was expected to become obsolete after sales of 400 units because of the development of supersonic airliners, but it has outlived many of its critics' expectations, and as of December 2007, 1,396 aircraft had been built. Source

February 7, 2008
An Interurban, also called a radial railway in parts of Canada, was a type of passenger railroad that enjoyed widespread popularity at the turn of the twentieth century in North America. Interurbans were often extensions of streetcar lines running between urban areas or from urban to rural areas. The lines were mainly electrified in an era when steam railroads had not yet adopted electricity to any large degree. Most could not survive following the widespread adoption of the automobile. Those that remained survived as commuter railroads or as freight short lines. Source

February 6, 2008
Extra-vehicular activity (EVA) is work done by an astronaut away from the Earth and outside of a spacecraft. EVAs may be either tethered (the astronaut is connected to the spacecraft, oxygen can be supplied through a tube, no propulsion is needed to return to the spacecraft) or untethered. The first EVA was carried out by Aleksei Leonov on March 18, 1965 from the Voskhod 2 spacecraft. The first untethered spacewalk was by Bruce McCandless II on February 7, 1984, from the Challenger space shuttle. Source

February 5, 2008
Mopeds are a class of low-powered motorized vehicles, generally two-wheeled. Moped classification is designed to allow the use of small motorised vehicles, avoiding the safety restrictions and licensing charges required of larger motorcycles. Some motorized bicycles, small scooters, and small motorcycles fit the definition of a moped. Source

February 4, 2008
Buckypaper is a thin sheet made from an aggregate of carbon nanotubes. Originally, it was fabricated as a way to handle carbon nanotubes, but it is currently being studied and developed into applications by several research groups, showing promise as a building material for aerospace vehicles, body armor and next-generation electronics and displays. Source

February 3, 2008
USS Nautilus was the world's first operational nuclear-powered submarine and the first vessel to complete a submerged transit across the North Pole. Nautilus was commissioned on September 30, 1954. Nautilus was powered by the S2W naval reactor, a pressurized water reactor produced for the US navy by Westinghouse Electric Corporation. In 1955 she put to sea for the first time and signaled her historic message: "Underway on nuclear power." Submerged throughout her shakedown cruise, she traveled 2,100 km (1,100 nautical miles) from New London, CT to San Juan, Puerto Rico and covered 2,223 km (1,200 nmi) in less than ninety hours. At the time this was the longest submerged cruise by a submarine and at the highest sustained speed ever recorded. Source

February 2, 2008
A radiosonde is a unit for use in weather balloons that measures various atmospheric parameters and transmits them to a fixed receiver. The radiosonde was invented and launched for the first time by Soviet meteorologist Pavel Molchanov in 1930. Modern radiosondes measure pressure, altitude, position, temperature, relative humidity, wind speed and direction, and sometimes ozone concentration. A rubber or latex balloon filled with either helium or hydrogen lifts the device up through the atmosphere. The maximum altitude to which the balloon ascends is determined by the diameter and thickness of the balloon. Balloon sizes can range from 150 grams to 3000 grams. As the balloon ascends through the atmosphere, the pressure decreases, causing the balloon to expand. Eventually, the balloon will expand to the extent that its skin will break, terminating the ascent. An 800 gram balloon will burst at about 30,000 meters (about 100,000 feet). Source

February 1, 2008
The Menai Suspension Bridge is a suspension bridge between the island of Anglesey and the mainland of Wales. Designed by Thomas Telford and completed in 1826, it is one of the first modern suspension bridges in the world. Construction of the bridge began in 1819 with the towers on either side of the strait. These were constructed from Penmon limestone and were hollow with internal cross-walls. Then came the sixteen huge chain cables, each made of 935 iron bars that support the 176 metre span. To avoid rusting, each cable was first soaked in linseed oil. The bridge was opened to much fanfare on January 30, 1826, and succeeded in reducing the 36 hour journey time from London to Holyhead by 9 hours. Source

January 31, 2008
The Sea Island Mathematical Manual was written by the Chinese mathematican Liu Hui of the Three Kingdoms era (220–280) as an extension of chapter 9 of The Nine Chapters on the Mathematical Art. This book contained many practical problems of surveying using geometry. This work provided detailed instructions on how to measure distances and heights with tall surveyor's poles and horizontal bars fixed at right angles to them. After comparing the development of surveying in China and the West, Frank Swetz concluded that "in the endeavours of mathematical surveying, China's accomplishments exceeded those realized in the West by about one thousand years." Source

January 30, 2008
Karl Benz' Patent Motorwagen, built in 1885, is widely regarded as the first purpose-built automobile. Benz unveiled it officially on July 3, 1886 on the Ringstraße in Mannheim, Germany. After developing a successful gasoline-powered two-stroke piston engine in 1873, Benz focused on developing a motorized vehicle. The Patent Motorwagen was a three-wheeler with a rear-mounted engine. It was constructed of steel tubing with woodwork panels, and the steel-spoked wheels and solid rubber tires were Benz's own design. Steering was by way of a toothed rack that pivoted the unsprung front wheel. Fully-elliptic springs were used at the back along with a live axle and chain drive on both sides. A simple belt system served as a kind of single-speed transmission, varying torque between an open disc and drive disc. Source

January 29, 2008
Eureka (Greek "I have found it") is an exclamation used as an interjection to celebrate a discovery. It is most famously attributed to the ancient Greek scholar Archimedes; he reportedly said "eureka!" when he stepped into a bath and noticed the water level rise -- he suddenly understood that the volume of water displaced must be equal to the volume of the part of his body he had submerged. This meant that the volume of irregular objects could be calculated with precision, a previously intractable problem. He is said to have been so eager to share it that he leapt out of his bathtub and ran through the streets of Syracuse naked. Source

January 28, 2008
The éolienne Bollée is an unusual wind turbine, unique for having a stator and a rotor, as a water turbine has. It was first patented in 1868 by Ernest Bollée in France. The éolienne Bollée was designed to be constructed in a modular form, allowing éoliennes of various sizes to be built. The actual turbine itself consists of two annular rings, the first being the stator, and the second being the rotor. The stator has more blades than the rotor. A counterweight system turned the turbine out of wind as the wind speed increased, thus preventing damage in very strong winds. Source

January 27, 2008
The Canadian National Railways Radio Department was the first national radio network in North America. It was developed, owned and operated by the Canadian National Railway between 1923 and 1932. The network's origins were in the establishment by CNR president and chairman Sir Henry Thornton of the CNR Radio Department after the CNR began installing radio sets in their passenger cars and needed stations to provide programming that passengers could listen to along the CNR's various routes, particularly its coast-to-coast transcontinental line. The general public could also receive the broadcasts if they lived in the vicinity of a CNR radio station. On October 9, 1923, the network made international news when it carried a broadcast of former British Prime Minister David Lloyd George being interviewed by reporters travelling with him on a Montreal to Toronto train. The first regularly-scheduled coast-to-coast network program produced by CN Radio was broadcast December 27, 1928. By the end of 1929 there were three hours of national programming a week. Source

January 26, 2008
The Beer Can Museum, located in East Taunton, Massachusetts, is a collection of more than 3,000 different beer cans, along with beer can art and crafts, beer can clothing, beer can telephones and radios, and a beer can and breweriana related library. Cans dating back to the mid-1930s are on display, as are beer can oddities and obsolete and current trends in beer packaging. The collection was started in 1978 by the museum's director and curator, Kevin Logan. The oldest can in the collection is a Krueger Ale can from the 1930s which is similar to the first beer can ever produced in 1935. Source

January 25, 2008
The Macintosh was the original Apple Macintosh personal computer. Introduced in January 1984 at the price of $2,495 US, it had a beige case containing a 9-inch monitor, and came with a keyboard and mouse. After its successor was introduced, it was rebadged as the Macintosh 128K to differentiate it. The centerpiece of the machine was an 8 MHz Motorola 68000 connected to a 128 KB DRAM by a 16-bit data bus. Source

January 24, 2008
The Caterpillar 797B is an ultra class mining truck. The 797B is one of the largest mechanical dump trucks in the world. It has a gross operating weight of 1,375,000 lbs (623,690 kg) and a payload weight of 380 US tons (344.7 t). It is powered by a 3550  hp, 24-cylinder, four-stroke diesel engine up to 42 mph (67 km/h). Unlike more modern designs that use a diesel-electric drivetrain configuration, the 797B utilizes a design similar to a mechanical transmission in a conventional automobile. Source

January 23, 2008
A Texas Tower lighthouse is a structure, similar to an off-shore oil platform, used as a platform for a lighthouse. The first example in the United States was the Buzzards Bay Light, located in Buzzards Bay, Massachusetts, and commissioned on November 1, 1961. Five other Texas tower lights were constructed. Source

January 22, 2008
The crawler-transporter is a tracked vehicle used to transport the Saturn V rocket, the Saturn IB rocket during Skylab and Apollo-Soyuz Test Project, and now the Space Shuttle, from NASA's Vehicle Assembly Building along the Crawlerway to Launch Complex 39. The crawler-transporters are the world's largest self-powered tracked vehicles. Each crawler-transporter weighs 6 million pounds (2,700 t) and has eight tracks, two on each corner. The crawler has 16 traction motors, powered by four 1,000 kW generators, in turn driven by two 2,750 hp (2,050 kW) Alco diesel engines. The crawler's tanks hold 5,000 gallons of diesel fuel (19 m³), and it burns 150 gal/mi (350 L/km). Source

January 21, 2008
The lunar rover, or moon buggy, was a type of electric vehicle used on the Moon during the Apollo program. Three of the Apollo missions brought rovers to the Moon. The Lunar Roving Vehicle had a weight of 463 lb (210 kg) and was designed to hold a payload of 1,080 lb (490 kg) on the lunar surface. The frame was made of aluminum alloy tubing and was hinged in the center so it could be folded up and hung in the Lunar Module. Each wheel had its own electric drive, a DC series wound 0.25 hp (200 W) motor capable of 10,000 rpm, attached to the wheel via an 80:1 harmonic drive, and a mechanical brake unit. Maneuvering capability was provided through the use of front and rear steering motors. Each series wound DC steering motor was capable of 0.1 hp (100 W). Both sets of wheels would turn in opposite directions, giving a steering radius of 10 feet (3 m), or could be decoupled so only one set would be used for steering. Power was provided by two 36-volt silver-zinc potassium hydroxide non-rechargeable batteries with a capacity of 121 A·h. Source

January 20, 2008
A harmonic drive is an input/output gear reduction mechanism. Very high reduction ratios are possible in a smaller volume than other common reduction systems. The harmonic drive theory is based on elastic dynamics and utilizes the flexibility of metal. The mechanism has three basic components: a wave generator, a flexspline, and a circular spline. The wave generator is an oblong elliptical plate that rotates on an input shaft. The motion of the wave generator cause the flexspline to move within the circular spline. The flexspline and circular spline have a differing number of teeth, causing the circular spline to move relative to the input shaft. By adjusting the number of teeth, different reduction ratios can be achieved. Harmonic drives have the advantage of being able to handle large amounts of torque. Source

January 19, 2008
The Arroyo Seco Parkway, more commonly known today as the Pasadena Freeway, was the first freeway in California, connecting Los Angeles with Pasadena alongside the Arroyo Seco. It is notable not only for being the first, mostly opened in 1940, but for representing the transitional phase between early parkways and modern freeways. Although the plants in the median have given way to a steel guardrail, the historic U.S. Route 66 has become State Route 110, and it officially became a "freeway" rather than a "parkway" in 1954, the road remains largely as it was on opening day. The original pavement mostly remains, with the passing lane colored differently in an attempt to keep drivers in their lanes. Source

January 18, 2008
The San Francisco and San Mateo Electric Railway (SF&SM) was the first electric streetcar company in San Francisco, California. The company was only in business for ten years, starting in 1892 until its merger into the United Railroads of San Francisco. After leaving the Ferry Building, the line went to 30th Street via Harrison, Guerrero, 14th Street, and San Jose Avenue. They were not able to traverse any of the major streets, as rival streetcar companies already had lines on them. Furthermore, beyond 30th Street, the area of the city was not yet fully settled. With an unpopular route that led to sparsely populated neighborhoods, the company could not generate much revenue despite having nearly 4,200,000 riders annually. This trend continued after the merger into URR well into the 1920s, when electric streetcars were at their most profitable. Source

January 17, 2008
The SR Merchant Navy Class, also known as Bulleid Pacifics, Spam Cans or Packets, was a class of air-smoothed 4-6-2 Pacific steam locomotive designed for the Southern Railway of the United Kingdom by Oliver Bulleid. The Pacific design was chosen in preference to several others proposed by Bulleid. The first members of the class were constructed during the Second World War, and the last of the 30 locomotives in 1949. Incorporating a number of new developments in British steam locomotive technology, the design of the Packets was among the first to use welding in the construction process; this enabled easier fabrication of components during the austerity of the war and post-war economies. The locomotives featured thermic syphons and Bulleid's controversial, innovative chain-driven valve gear. Source

January 16, 2008
The MErcury Surface, Space ENvironment, GEochemistry and Ranging probe (or MESSENGER for short) is a NASA spacecraft, launched August 3, 2004 to study the characteristics and environment of Mercury from orbit. Specifically, the mission is to characterize the chemical composition of Mercury's surface, the geologic history, the nature of the magnetic field, the size and state of the core, the volatile inventory at the poles, and the nature of Mercury's exosphere and magnetosphere over a nominal orbital mission of one Earth year. The mission is the first to visit Mercury in over 30 years; the only previous probe to visit Mercury was Mariner 10, which completed its mission in March 1975. Source

January 14, 2008
Mount Lucania is the third highest mountain in Canada. The first ascent of Mount Lucania was made in 1937 by Bradford Washburn and Robert Hicks Bates. They used an airplane to reach Walsh Glacier, 8,750 ft (2,670 m) above sea level; the use of air support for mountaineering was novel at the time. Washburn called upon Bob Reeve, a famous Alaskan bush pilot, who later replied by cable to Washburn, "Anywhere you'll ride, I'll fly". The ski-equipped Fairchild F-51 made several trips to the landing site on the glacier without event in May, but on landing with Washburn and Bates in June, the plane sank into unseasonal slush. Washburn, Bates and Reeve pressed hard for five days to get the airplane out and Reeve was eventually able to get the airplane airborne with all excess weight removed and with the assistance of a smooth icefall with a steep drop. Washburn and Bates continued on foot to make the first ascent of Lucania, and after an epic descent and journey to civilization, they hiked over 150 miles through the wilderness to safety in the small town of Burwash Landing in the Yukon. Source

January 13, 2008
An optical fiber is a glass or plastic fiber designed to guide light along its length. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Optical fibers are widely used in fiber-optic communication, which permits transmission over longer distances and at higher data rates than other forms of communications. Fibers are used instead of metal wires because signals travel along them with less loss, and they are immune to electromagnetic interference. Optical fibers are also used to form sensors, and in a variety of other applications. Source

January 12, 2008
The America was a non-rigid airship built by Mutin Godard in France in 1906 for Walter Wellman's attempt to reach the North Pole by air. Wellman had been inspired to fly to the pole during a failed overland attempt in 1893. When he saw a French dirigible at the Portsmouth Peace Conference in 1905, he believed that he had found his solution. After several failed attempts to reach the pole, Wellman resolved to make the first aerial crossing of the Atlantic Ocean. He had the America enlarged to 345,000 cu ft (9,760 m³) and on 15 October 1910 took off from Atlantic City. The engines failed 38 hours into the flight, and America drifted. After 33 hours, and having now travelled a total distance of 1,370 miles (2,200 km) from launching, they sighted the Royal Mail steamship Trent near Bermuda and abandoned the America in a lifeboat. America drifted out of sight and was never seen again. Source

January 11, 2008
The ship's cat has been a common sight on many trading, exploration, and naval ships, and is a phenomenon that goes back to ancient times. Cats have been carried on ships for a number of reasons, the most important being that mice and rats, which would inevitably find their way aboard a ship, could cause considerable damage to ropes and woodwork. More serious was the threat they posed to the stores the ship carried. Not only could they devour the foodstuff carried to feed the crew, if the ship was carrying grain or similar substances as part of its cargo, then they could cause economic damage as well. Rats and mice were also sources of disease, an important consideration when the ship could be at sea for a long period of time. Cats naturally attack and kill these rodents. Source

January 10, 2008
An autogyro is a type of rotorcraft invented by Juan de la Cierva in 1919, making its first successful flight on January 9, 1923 at Cuatro Vientos Airfield in Madrid, Spain. Similar to helicopters, autogyros use a rotor to develop lift. While a helicopter's rotor is rotated by an engine during normal flight, the rotor of an autogyro is driven by aerodynamic forces in autorotation. An engine-powered propeller, similar to that of a fixed-wing aircraft, provides thrust for the autogyro. An autogyro is characterised by a free-spinning rotor that turns due to passage of air upwards through the rotor. The vertical component of the total aerodynamic reaction of the rotor gives lift for the vehicle, and sustains the autogyro in the air. A separate propeller provides forward thrust. Source

January 9, 2008
The Westinghouse Time Capsules are two time capsules created for the 1939 and 1964 New York World's Fairs. Both are buried below Flushing Meadows Park and are to be opened at the same time in 6939 AD. The two time capsules are bullet-shaped, measure 90 inches (2.29 m) in length, and have an exterior casing of about eight and three-eighths inches (21.1 cm) in diameter. Time Capsule I weighs about 800 pounds (363 kg), while Time Capsule II weighs about half that. Time Capsule I was made of a non-ferrous alloy called Cupaloy, created especially for this project. Designed to resist corrison for 5,000 years, the alloy was made of 99.4% copper, 0.5% chromium, and 0.1% silver. Time Capsule II was made of a stainless steel metal called "Kromarc". The contents for the time capsules were sealed inside an insulated airtight glass envelope with an interior diameter of six and a half inches (16.5 cm) and a length of about 81 inches (2 m). The interior of the glass envelope of Capsule I was filled with the inert gas nitrogen. The interior of the glass envelope of Capsule II was filled with the inert gas argon. The term "time capsule" was coined by George Edward Pendray for the New York 1939 World's Fair Westinghouse exhibit. Source

January 8, 2008
The Linn Tractor was a heavy duty civilian half-track or crawler tractor invented by Holman Linn. Approximately 2500 units were built in Morris, New York USA from 1916 to 1952. Linn was a native of Maine and in his quest for a better machine to travel rural roads with his dog and pony show equipment, he gave up on a six wheel drive design, and in 1907 had Alvin Lombard build a machine using the tracks off a Lombard Steam Log Hauler, an underslung gasoline engine and wheels on front. It was equipped with a ship style cabin with living quarters and able to pull string of wagons behind as well as supply electric lights for his circus. Source

January 7, 2008
Sound from ultrasound is when modulated ultrasound can make its carried signal audible without needing a receiver set. This happens when the modulated ultrasound passes through anything which behaves nonlinearly and thus acts intentionally or unintentionally as a demodulator. Scuba divers and naval submarines have been using modulated ultrasound underwater communicators for many years, but to hear the sound signal needed a receiver set to demodulate the received ultrasound signal. Researchers since the early 1960s have been experimenting with creating directive low-frequency sound from nonlinear interaction of an aimed beam of ultrasound waves produced by a parametric array. Ultrasound has wavelengths much smaller than audible sound and thus can be aimed in a much tighter narrow beam than any traditional audible loudspeaker system. Source

January 6, 2008
Galileo Galilei (1564 – 1642) was a Tuscan physicist, mathematician, astronomer, and philosopher who played a major role in the scientific revolution. His achievements include the first systematic studies of uniformly accelerated motion, improvements to the telescope and consequent astronomical observations, and support for Copernicanism. On January 7, 1610 Galileo observed with his telescope what he described at the time as "three fixed stars, totally invisible by their smallness", all within a short distance of Jupiter, and lying on a straight line through it. Within a few days he concluded that they were orbiting Jupiter: he had discovered three of Jupiter's four largest satellites: Io, Europa, and Callisto. Source

January 5, 2008
Philip H. Diehl (1847 – 1913) was a German-American engineer and inventor who held several U.S. patents, including electric incandescent lamps, electric motors for sewing machines and other uses, and ceiling fans. Diehl was a contemporary of Thomas Edison and his inventions caused Edison to reduce the price of his incandescent bulb. The electric fan was invented in 1882 by Schuyler Skaats Wheeler. A few years later, Philip Diehl mounted a fan blade on a sewing-machine motor and attached it to the ceiling, inventing the ceiling fan, which he patented in 1887. Later, he added a light fixture to the ceiling fan. In 1904, his Diehl and Co. added a split-ball joint, allowing it to be redirected; three years later, this developed into the first oscillating fan. Source

January 4, 2008
Eris is the largest known dwarf planet in the Solar System and the ninth largest body known to orbit the Sun directly. It is approximately 2,500 kilometres in diameter and 27% more massive than Pluto. Eris was first spotted in 2003 by a Mount Palomar-based team led by Mike Brown but not identified until 2005. It is a trans-Neptunian object native to a region of space beyond the Kuiper belt known as the scattered disc. Eris has one moon, Dysnomia; recent observations have found no evidence of further satellites. The current distance from the Sun is 96.7 AU, roughly three times that of Pluto. With the exception of some comets, the pair are the most distant known bodies in the Solar System. Source

January 3, 2008
An arch-gravity dam, such as the Hoover Dam, is a dam with the characteristics of both an arch dam and a gravity dam. It is a dam that curves upstream in a narrowing curve that directs most of the water against the canyon rock walls, providing the force to compress the dam. It combines the strengths of two common dam forms and is considered a compromise between the two. A gravity dam requires a large volume of internal fill. An arch-gravity dam can be thinner than the pure gravity dam and requires less internal fill. Arch-gravity dams are massive dams of reinforced concrete that resist the thrust of water by their weight pushing down using the force of gravity. A gravity dam is constructed so that the dam's massive weight resists the pressure of the water against it. At the same time an arch-gravity dam incorporates the arch's curved design that is so effective in deflecting the water in narrow, rocky locations where the gorge's side are of hard rock and the water is forced into a narrow channel. Therefore the span needed for the dam is narrow; the dam's curved design effectively holds back the water in the reservoir using a lesser amount of construction material. Source

January 2, 2008
A biplane is a fixed-wing aircraft with two main wings. The first powered heavier-than-air aircraft, the Wright brothers' Wright Flyer, used a biplane design, as did most airplanes in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing. Improved structural techniques and materials, and the need for greater speed, effectively made the biplane configuration obsolete for most purposes by the late 1930s. Source

January 1, 2008
The Deperdussin Monocoque was a pioneer-era aircraft first produced in 1912 by the Société Pour les Appareils Deperdussin, a French aviation company. Designed as a racing aircraft, the Deperdussin Monocoque was a slim, single-seated plane with a sleek aerodynamic build that was the first of a large range of similar designs that would come in later years. The design is noted for winning the Gordon Bennett Trophy in 1912, and for being the first aircraft to exceed 100 miles (160 km) per hour, and, ultimately, was able to reach a pinnacle of 125 miles (201 km) an hour, the fastest the model was recorded to fly. Source

December 31, 2007
The Magnetoplasmadynamic thruster is a form of spacecraft propulsion which uses the Lorentz force to generate thrust. Generally, a gaseous fuel is ionized and fed into an acceleration chamber, where the magnetic and electrical fields are created using a power source. The particles are then propelled by the Lorentz force resulting from the interaction between the current flowing through the plasma and the magnetic field (which is either externally applied, or induced by the current) out through the exhaust chamber. Unlike chemical propulsion, there is no combustion of fuel. As with other electric propulsion variations, both specific impulse and thrust increase with power input. Various propellants such as xenon, neon, argon, hydrazine, and lithium have been used, with lithium generally being the best performer. Source

December 30, 2007
The Baghdad Battery is the common name for a number of artifacts created during the Iranian dynasty of Parthia and was probably discovered in a village near Baghdad, Iraq in 1936. These artifacts came to wider attention in 1940 when Wilhelm König published a paper speculating that they may have been galvanic cells, perhaps used for electroplating gold onto silver objects. The artifacts consist of 5 inch tall terracotta jars containing a copper cylinder made of a rolled-up copper sheet, which houses a single iron rod. At the top, the iron rod is isolated from the copper by asphalt plugs or stoppers, and both rod and cylinder fit snugly inside the opening of the jar which bulges outward towards the middle. Some scholars believe lemon juice, grape juice, or vinegar was used as an acidic agent to jumpstart the electrochemical reaction with the two metals. Source

December 29, 2007
Composite honeycomb is a material used as a core material in Sandwich structured composite structures. Composite honeycomb takes its name from its visual resemblance to a bee's honeycomb - a hexagonal sheet structure. Composite honeycombs are constructed of composite materials such as glass-reinforced plastic (better known as fiberglass), carbon fiber reinforced plastic, nomex reinforced plastic, kevlar reinforced plastic, or sometimes a metal (usually aluminum). Source

December 28, 2007
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices. Their primary function is to aid in the generation of both thrust and lift, thereby enabling flight. The flight feathers of some birds have evolved to perform additional functions, generally associated with territorial displays, courtship rituals or feeding methods. In some species, these feathers have developed into long showy plumes used in visual courtship displays, while in others they create a sound during display flights. Tiny serrations on the leading edge of their remiges help owls to fly silently, while the extra-stiff rectrices of woodpeckers help them to brace against tree trunks as they hammer. Even flightless birds still retain flight feathers, though sometimes in radically modified forms. Source

December 27, 2007
Reginald Aubrey Fessenden (1866 – 1932), born in Quebec, Canada, was an inventor, best known for his work in early radio. In 1900, Fessenden was working for the United States Weather Bureau where he evolved the heterodyne principle where two signals combined produce a third audible tone. While there, Fessenden, experimenting with a high-frequency spark transmitter, successfully transmitted speech on December 23, 1900 over a distance of about one mile, which appears to have been the first audio radio transmission. Source

December 25, 2007
Computational humor is a branch of computational linguistics and artificial intelligence which uses computers in humor research. It is not to be confused with computer humor (i.e., jokes about computers, programmers, users, and computing). It is a relatively new area, with the first dedicated conference organized in 1996. An approach to analysis of humor is classification of jokes. A further step is an attempt to generate jokes basing on the rules that underlie classification. Simple prototypes for computer pun generation were reported in the early 1990s. An exampe is: Q: What is the difference between leaves and a car? A: One you brush and rake, the other you rush and brake. Source

December 24, 2007
Belsnickel is a Pennsylvania Dutch mythical being who visits children at Christmas time. If they have not been good, they will find coal and/or switches in their stockings. The Belsnickel was a scary creature not well loved except by parents wanting to keep their children in line. Among some families of German decent, Bensnickle delivers socks or shoes full of candy to children on the feast day of St. Nicholas, December 6. St. Nicholas is purported to have enabled the three daughters of a poor man to pay the dowries for their weddings. The poor man couldn’t afford his daughters’ dowries so Nicholas came to the man’s house at night and snuck three sacks of gold into the house thus saving the daughters from the indignity of a solitary life or prostitution. Source

December 23, 2007
The Creusot steam hammer was a giant steam hammer built in 1877 by Schneider and Co. in the French industrial town of Le Creusot. With the ability to deliver a blow of up to 100 tons, the Creusot hammer was the most powerful in the world until 1891. The Creusot hammer still exists, although it is no longer operational, and is a tourist attraction in the town of Le Creusot where it was built. With few remaining rivals, the hammer today is once again the largest of its kind in the world. In its heyday, the hammer would sometimes give public demonstrations of its accuracy. It could be used to cork a bottle, crack a nut without damaging the contents, or tap a watch glass without breaking it. With such demonstrations, steam hammers for a time became symbols of industrial precision. Source

December 22, 2007
Finavera Renewables Inc. is a publicly traded company that develops and manufactures wind and wave energy projects in several countries. Finavera Renewables is developing a unique wave energy techonology called "AquaBuOy". Energy transfer takes place by converting the vertical component of wave kinetic energy into pressurized seawater by means of two-stroke hose pumps. Pressurized seawater is directed into a conversion system consisting of a turbine driving an electrical generator. The power is transmitted to shore by means of an undersea transmission line. Source

December 21, 2007
Drunken trees, tilted trees, or a drunken forest, is a stand of trees displaced from their normal vertical alignment. This most commonly occurs in northern subarctic taiga forests of Black Spruce under which discontinuous permafrost or ice wedges have melted, causing trees to tilt at various angles. Tilted trees may also be caused by frost heaving, and subsequent palsa development, hummocks, earthflows, forested active rock glaciers, landslides, or earthquakes. Source

December 20, 2007
The Amazon Mechanical Turk is a crowdsourcing marketplace that enables computer programs to co-ordinate the use of human intelligence to perform tasks which computers are unable to do. Requesters, the human beings that write these programs, are able to pose tasks known as Human Intelligence Tasks, such as choosing the best among several photographs of a storefront, writing product descriptions, or identifying performers on music CDs. Workers can then browse among existing tasks and complete them for a monetary payment set by the Requester. The name Mechanical Turk comes from "The Turk", a chess-playing automaton of the 18th century, which was made by Wolfgang von Kempelen. It toured Europe beating the likes of Napoleon Bonaparte and Benjamin Franklin. It was later revealed that this 'machine' was not an automaton at all but was in fact a chess master hidden in a special compartment controlling its operations. Source

December 19, 2007
The Google Earth Flight Simulator is a hidden feature found in Google Earth v4.2. It can be accessed by holding Control+Alt+A or Apple+Alt+A at the same time. After this feature has been activated at least one time it appears under the tools menu. Two different aircraft that can be used, in addition to a few airports. Source

December 18, 2007
Dealkalization is a process of surface modification applicable to glasses containing alkali ions, wherein a thin surface layer is created that has a lower concentration of alkali ions than is present in the underlying, bulk glass. This change in surface composition commonly alters the observed properties of the surface, most notably enhancing corrosion resistance. Source

December 17, 2007
Cassini–Huygens is a joint NASA/ESA/ASI robotic spacecraft mission currently studying the planet Saturn and its moons. The spacecraft consists of two main elements: the NASA Cassini orbiter, named after the Italian-French astronomer Giovanni Domenico Cassini, and the ESA Huygens probe, named after the Dutch astronomer, mathematician and physicist Christiaan Huygens. The Huygens probe reached Saturn's moon Titan on January 14, 2005, where it made an atmospheric descent to the surface and relayed scientific information. It is the first spacecraft to orbit Saturn and the fourth to visit Saturn. Source

December 16, 2007
The Wright Flyer was the first powered aircraft designed and built by the Wright brothers. It was the first successful powered, piloted, controlled heavier-than-air aircraft. The first successful flight of the Wright Flyer was made at Kitty Hawk, North Carolina on December 17, 1903. Source

December 15, 2007
Gasification is a process that converts carbonaceous materials, such as coal, petroleum, or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen. The resulting gas mixture is called synthesis gas or syngas and is itself a fuel. Gasification is a very efficient method for extracting energy from many different types of organic materials, and also has applications as a clean waste disposal technique. The advantage of gasification is that using the syngas is more efficient than direct combustion of the original fuel; more of the energy contained in the fuel is extracted. Gasification can also begin with materials that are not otherwise useful fuels, such as biomass or organic waste. Source

December 14, 2007
A water-tube boiler is a type of boiler in which water circulates in tubes which are heated externally by the fire. Water-tube boilers are used for high-pressure boilers. Fuel is burned inside the furnace, creating hot gas which heats up water in the steam-generating tubes. The heated water then rises into the steam drum. Here, saturated steam is drawn off the top of the drum. In some services, the steam will reenter the furnace in through a superheater in order to become superheated. Cool water at the bottom of the steam drum returns to the feedwater drum via large-bore 'downcomer tubes', where it helps pre-heat the feedwater supply. To increase the economy of the boiler, the exhaust gasses are also used to pre-heat the air blown into the furnace and warm the feedwater supply. Such water-tube boilers in thermal power station are also called steam generating units. Source

December 13, 2007
Leonardo di ser Piero da Vinci, (1452 – 1519) was a Tuscan polymath: scientist, mathematician, engineer, inventor, anatomist, painter, sculptor, architect, botanist, musician, poet and writer. As an engineer, Leonardo conceived ideas vastly ahead of his own time, conceptualising a helicopter, a tank, concentrated solar power, a calculator, and the double hull, and outlining a rudimentary theory of plate tectonics. Relatively few of his designs were constructed or even feasible during his lifetime, but some of his smaller inventions such as an automated bobbin winder and a machine for testing the tensile strength of wire entered the world of manufacturing unheralded. As a scientist, he greatly advanced the state of knowledge in the fields of anatomy, civil engineering, optics, and hydrodynamics. Source

December 12, 2007
A nutating disc engine is a recently patented internal combustion engine comprising fundamentally only one moving part and a direct drive onto the crankshaft. In its basic configuration the core of the engine is a nutating non-rotating disc, with the center of its hub mounted in the middle of a Z-shaped shaft. The two ends of the shaft rotate, while the disc "nutates," (performs a wobbling motion without rotating around its axis). The motion of the disk circumference prescribes a portion of a sphere. A portion of the area of the disc is used for intake and compression, a portion is used to seal against a center casing, and the remaining portion is used for expansion and exhaust. The compressed air is admitted to an external accumulator, and then into an external combustion chamber before it is admitted to the power side of the disc. The external combustion chamber enables the engine to use diesel fuel in small engine sizes, giving it unique capabilities for unmanned aerial vehicle propulsion and other applications. Source

December 11, 2007
A narrow gauge railway is a railway that has a track gauge narrower than the 1,435 mm (4 ft 8½ in) of standard gauge railways. Most existing narrow gauge railways have gauges of 3 ft 6 in (1,067 mm) or less. Since narrow gauge railways are usually built with smaller radius curves and smaller structure gauges, they can be substantially cheaper to build, equip, and operate than standard gauge or broad gauge railways, particularly in mountainous terrain. The lower costs of narrow gauge railways mean they are often built to serve industries and communities where the traffic potential would not justify the costs of building a standard or broad gauge line. Narrow gauge railways also have specialized use in mines and other environments where a very small structure gauge makes a very small loading gauge necessary. On the other hand, standard gauge or broad gauge railways generally have a greater haulage capacity and allow greater speeds than narrow gauge systems. Source

December 10, 2007
Jerrygibbsite (Mn,Zn)9(SiO4)4(OH)2 is a very little known mineral, most likely a member of the leucophoenicite family, but a possible member of the humite group. Jerrygibbsite was originally discovered by Pete J. Dunn in 1984 and named after a professor at Virginia State University and Virginia Polytechnic Institute, Professor Gerald V. Gibbs. It is a very rare mineral of which there are only five known samples, the first three of which have all been discovered in Franklin, New Jersey in 1984, and the last two in Namibia, also by Pete Dunn, in 1988. Jerrygibbsite is closely related to both the leucophoenite family and the Humite group by both crystal structure and chemical composition. It is always found with these two minerals, and is most likely a polymorph between leucophoenicite and the humite group mineral, sonolite. Source

December 9, 2007
Robert William Thomson (1822-1873) from Stonehaven, Scotland was the original inventor of the pneumatic tyre. Among his other inventions were the elliptic rotary steam engine and locomotive traction engine, the portable steam crane, and numerous others. Source

December 8, 2007
Thundersnow also known as a Winter Thunderstorm or a Thunder Snowstorm is a particularly rare meteorological phenomenon that includes the typical behavior of a thunderstorm, but with snow falling as the primary precipitation instead of rain. It commonly falls in regions of strong upward motion within the cold sector of extratropical cyclones between autumn and spring when surface temperatures are most likely to be near or below freezing. Variations exist, such as thundersleet, where the precipitation consists of sleet rather than snow. Source

December 7, 2007
Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. The fact that electromagnetic radiation exerts a pressure upon any surface exposed to it was deduced theoretically by James Clerk Maxwell in 1871 and Adolfo Bartoli in 1876, and proven experimentally by Lebedev in 1900 and by Ernest Fox Nichols and Gordon Ferrie Hull in 1901. The pressure is very feeble, but can be detected by allowing the radiation to fall upon a delicately poised vane of reflective metal in a Nichols radiometer. Solar sails, a proposed method of spacecraft propulsion, would use radiation pressure from the Sun as a motive force. Mariner 10 used the solar radiation pressure on its solar panels and its high-gain antenna as a means of attitude control during flight, the first spacecraft to use active solar pressure control. Source

December 6, 2007
A distributary, or a distributary channel, is a stream that branches off and flows away from a main stream channel. They are a common feature of river deltas. The phenomenon is known as river bifurcation. The opposite of a distributary is a tributary. Distributaries usually occur as a stream nears a lake or the ocean, but they can occur inland as well, such as in an endorheic basin, or when a tributary stream bifurcates as it nears its confluence with a larger stream. In some cases, a minor distributary can "steal" so much water from the main channel that it can become the main route. Source

December 5, 2007
The Encyclopædia Britannica is a general English-language encyclopaedia published by Encyclopædia Britannica, Inc., a privately held company located in Chicago, USA. The articles are written by a staff of 19 full-time editors and over 4,000 expert contributors. The Britannica is the oldest English-language encyclopaedia still in print. It was first published between 1768 and 1771 in Edinburgh and quickly grew in popularity and size, with its third edition in 1801 reaching 20 volumes. Beginning with the 11th edition, the Britannica gradually shortened and simplified its articles to make them more accessible and to broaden its North American market. In 1933, the Britannica became the first encyclopaedia to adopt a "continuous revision" policy, in which the encyclopaedia is continually reprinted and every article is updated on a regular schedule. Source

December 4, 2007
The Nitrogen-vacancy center is a crystallographic defect in the structure of a diamond that can be exploited to capture the electron spin and create a spintronic device. Utilized with the emerging technology of spintronics, the N-V center may facilitate an atomic-scale system for solid information processing, and numerous other important applications in quantum electronics and quantum cryptography. The existence of N-V centers was discovered in 1997 by a research team led by Jorg Wrachtrup, at the Chemnitz University of Technology in Germany. Source

December 3, 2007
NASA developed dichroic glass for use in satellite mirrors. Multiple ultra-thin layers of different metal oxides (gold, silver, titanium, chromium, aluminium, zirconium, magnesium, silicon) are evaporated on to the surface of the glass in a vacuum chamber. These thin layers of oxides have a total thickness of three to five millionths of an inch. The resulting plate of dichroic glass can then be fused with other glass in multiple firings. Certain wavelengths of light will either pass through or be reflected, causing an array of colour to be visible. Due to variations in the firing process, individual results can never be exactly reproduced; each piece of fused dichroic glass is unique. Source

December 2, 2007
On 10 December 1868, the first traffic lights were installed outside the British Houses of Parliament in London, by the railway engineer J. P. Knight. They resembled railway signals of the time, with semaphore arms and red and green gas lamps for night use. The gas lantern was turned with a lever at its base so that the appropriate light faced traffic. Unfortunately, it exploded on 2 January 1869, injuring the policeman who was operating it. The modern electric traffic light is an American invention. As early as 1912 in Salt Lake City, Utah, policeman Lester Wire invented the first red-green electric traffic lights. On 5 August 1914, the American Traffic Signal Company installed a traffic signal system on the corner of 105th Street and Euclid Avenue in Cleveland, Ohio. It had two colors, red and green, and a buzzer, based on the design of James Hoge, to provide a warning for color changes. The design by James Hoge allowed Police and Fire stations to control the signals in case of emergency. The first four-way, three-color traffic light was created by police officer William Potts in Detroit in 1920. Source

December 1, 2007
In hydrodynamics, the clapotis is a non-breaking standing wave pattern, caused for example, by the reflection of a traveling surface wave train from a near vertical shoreline like a breakwater, seawall or steep cliff. The resulting clapotic wave does not travel horizontally, but has a fixed pattern of nodes and antinodes. These waves promote erosion at the toe of the wall, and can cause severe damage to shore structures. Source

November 30, 2007
Baltimore Clipper is the colloquial name for fast sailing ships built on the south-eastern seaboard of the United States of America, especially at the port of Baltimore, Maryland. It is most commonly applied to two-masted schooners and brigantines. Baltimore clippers were first built as small, fast sailing vessels for trade around the coastlines of the United States and the Caribbean Islands. Their hull-lines tended to be very sharp, with a "V"-shaped cross-section below the waterline and strongly raked stem and stern posts. Source

November 29, 2007
The Crystal Palace was a wrought iron and glass building originally erected in Hyde Park, London, England, to house the Great Exhibition of 1851. More than 14,000 exhibitors from around the world gathered in the Palace's 990,000 square feet of exhibition space to display examples of the latest technology developed in the Industrial Revolution. Designed by Joseph Paxton, the Great Exhibition building was 1,850 feet (564 m) long and 110 feet (34 m) tall, with an interior height of 408 feet (124 m). The Crystal Palace burned down in 1936 and was not rebuilt. Source

November 28, 2007
The phonograph, or gramophone, was the most common device for playing recorded sound from the 1870s through the 1980s. Thomas Alva Edison announced his invention of the first phonograph, a device for recording and replaying sound, on November 21, 1877 and he demonstrated the device for the first time on November 29. Edison's early phonographs recorded onto a tinfoil sheet phonograph cylinder using an up-down ("hill-and-dale") motion of the stylus. The tinfoil sheet was wrapped around a grooved cylinder, and the sound was recorded as indentations into the foil. Source

November 27, 2007
A DNA machine is a molecular machine constructed from DNA. Research into DNA machines was pioneered in the late 1980s by Nadrian Seeman and co-workers from New York University. DNA is used because of the numerous biological tools already found in nature that can affect DNA, and the immense knowledge of how DNA works previously researched by biochemists. An example of a DNA machine was reported by Andrew Turberfield and co-workers at Lucent Technologies in the year 2000, who constructed molecular tweezers out of DNA. Source

November 26, 2007
Nesjavellir is the largest geothermal power plant in Iceland. Plans for utilizing the Nesjavellir area for geothermal power and water heating began in 1947 -- some boreholes were drilled to evaluate the area's potential for power generation. Research continued from 1965 to 1986. In 1987, the construction of the plant began, and the cornerstone was laid in May 1990. The station produces approximately 120 megawatts (MW) of electrical power, and delivers around 1800 litres of hot water per second, servicing the Greater Reykjavík Area's hot water needs. Source

November 25, 2007
Cross-linked polyethylene, commonly abbreviated PEX or XLPE, is a form of polyethylene with cross-links. It is formed into tubing, and is used predominantly in hydronic radiant heating systems, domestic water piping and insulation for high tension electrical cables. It is also used for natural gas and offshore oil applications, chemical transportation, and transportation of sewage and slurries. Recently, it has become a viable alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper pipe for use as residential water pipes. Source

November 24, 2007
Jean-François Pilâtre de Rozier (1754 – 1785) was a French chemistry and physics teacher, and one of the first pioneers of aviation. His balloon crashed near Wimereux in the Pas-de-Calais during an attempt to fly across the English Channel, and he and his companion, Pierre Romain, became the first known victims of an air crash. Source

November 23, 2007
Copper sheathing was the practise of protecting the under-water hull of a ship or boat through the use of copper plates affixed to the outside of the hull. It was pioneered and developed by the Royal Navy during the 18th century. Deterioration of the hull of a wooden ship was a significant problem during the Age of Sail. Several methods were developed for protecting it from attack by shipworm and the various marine weeds, with copper sheathing being one of the most effective. After dealing with various engineering problems such as the electrolytic reaction between the copper and iron, copper sheathing finally came into widespread use by ships of the British Navy in the 1770's. Source

November 22, 2007
A nuclear thermal rocket is a rocket engine design utilizing a working fluid, usually hydrogen, heated in a high temperature nuclear reactor, and then expanding through a rocket nozzle to create thrust. The nuclear reactor's energy replaces the chemical energy of the reactive chemicals in a traditional rocket engine. Due to the higher energy density of the nuclear fuel compared to chemical ones, about 107 times, the resulting efficiency of the engine is at least twice as good as chemical engines even considering the weight of the reactor, and even higher for advanced designs. A nuclear engine was considered for some time as a replacement for the J-2 used on the S-II and S-IVB stages on the Saturn V and Saturn I rockets. To date, no nuclear thermal rocket has flown, or even reached a stage of development where it could be. Political considerations make it unlikely such an engine will be used in the foreseeable future. Source

November 21, 2007
Operation Deep Freeze is the codename for a series of US missions to Antarctica, beginning with "Operation Deep Freeze I" in 1955–56. "Operation Deep Freeze" has come to be used as a general term for US operations in that continent, and in particular for the regular missions to resupply US Antarctic bases, coordinated by the US military. The impetus behind Operation Deep Freeze I was the International Geophysical Year 1957–58. IGY, as it was known, was a collaboration effort between forty nations to carry out earth science studies from the North Pole to the South Pole and at points in between. The United States, along with Great Britain, France, Japan, Norway, Chile, Argentina, and the U.S.S.R. agreed to go to the South Pole—the least explored area on Earth. Their goal was to advance world knowledge of Antarctic hydrography and weather systems, glacial movements, and marine life. The U.S. Navy was charged with supporting the U.S. scientists for their portion of the IGY studies. Source

November 20, 2007
Chromate conversion coating is a type of conversion coating applied to passivate aluminum, zinc, cadmium, copper, silver, magnesium, tin and their alloys to slow corrosion. The process uses various toxic chromium compounds which may include hexavalent chromium. Chromating is commonly used on zinc-plated parts to protect the zinc from white corrosion, which is primarily a cosmetic issue. It cannot be applied directly to steel or iron, and does not enhance zinc's anodic protection of the underlying steel from brown corrosion. It is also commonly used on aluminum alloy parts in the aircraft industry where it is often called chromate conversion film. Source

November 19, 2007
The Antonov An-225 is a strategic airlift transport aircraft which was built by Antonov, and is the world's largest flying airplane ever built by the most commonly accepted measure, maximum gross takeoff weight. The design, built to transport the Buran orbiter, was an enlargement of the successful An-124. With a maximum gross weight of 640 tonnes (1,411,000 lb), the An-225 is the world's heaviest and largest aircraft. The Hughes H-4 Hercules, known to most as the "Spruce Goose", had a greater wingspan and a greater overall height, but was considerably shorter, and due to the materials used in its construction, also lighter. Source

November 18, 2007
The Venera series of probes was developed by the USSR between 1961 and 1984 to gather data from Venus. Eight probes from the Venera series successfully landed on Venus and transmitted data from the surface. The Venera probes were the first man-made devices to enter the atmosphere of another planet (Venera 4 on October 1967), to make a soft landing on another planet (Venera 7 on December 15, 1970), to return images from the planetary surface (Venera 9 on June 8, 1975) and to perform high-resolution radar mapping studies of Venus (Venera 15 on June 2, 1983). Unfortunately, while Venus' orbit is closer to Earth than Mars, its surface conditions are far more extreme, which meant that the probes did not survive long. Some of the pictures taken by the Venera probes can be viewed here. Source

November 17, 2007
The Buran spacecraft was the only fully completed and operational space shuttle from the Soviet Union's Buran program. It had only one unmanned spaceflight, in 1988, before the program was cancelled in 1993. It was lifted into orbit by the specially designed Energia booster rocket. During it's only space flight, the life support system was not installed and no software was installed to run the computer display screens. The shuttle orbited the Earth twice in 206 minutes of flight. On its return, it performed an automated landing on the shuttle runway at Baikonur Cosmodrome, where despite a lateral wind speed of 17 metres/second it made a successful landing only 3 metres laterally and 10 metres longitudinally from the target. The Buran was destroyed by a hangar collapse in 2002. Source

November 16, 2007
A Fresnel lens is a type of lens invented by French physicist Augustin-Jean Fresnel. Originally developed for lighthouses, the design enables the construction of lenses of large aperture and short focal length without the weight and volume of material which would be required in conventional lens design. The Fresnel lens reduces the amount of material required compared to a conventional spherical lens by breaking the lens into a set of concentric annular sections known as Fresnel zones. Compared to earlier lenses, the Fresnel lens is much thinner, thus passing more light and allowing lighthouses to be visible over much longer distances. Source

November 15, 2007
The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Intel purports it is the world's first commercial microprocessor. The 4004 employed a 10 μm silicon-gate PMOS technology and could execute approximately 92,000 instructions per second. The Intel 4004 is one of world's most sought-after collectible/antique chips. Source

November 14, 2007
Mariner 9 was a NASA space probe orbiter that helped in the exploration of Mars and was part of the Mariner program. Mariner 9 was launched toward Mars on May 30, 1971 from Cape Canaveral Air Force Station and reached the planet on November 13 of the same year, becoming the first spacecraft to orbit another planet — only narrowly beating Soviet Mars 2 and Mars 3, which both arrived within a month. After months of dust-storms it managed to send back surprisingly clear pictures of the surface. Source

November 13, 2007
A narrowboat is a boat of a distinctive design, made to fit the narrow canals in the British Isles. The original working boats were built in the 18th, 19th, and early 20th centuries for carrying goods on the narrow canals (where locks and bridge holes would have a minimum width of 7 feet) . The term is extended to modern "narrowboats" used as homes and for recreation, whose design is an interpretation of the old boats for modern purposes and modern materials. The key distinguishing feature of a narrowboat is its width: it must be no more than 7 feet wide to navigate the British narrow canals. The first working narrow boats played a key part in the economic changes accompanying the British Industrial Revolution. They were wooden boats drawn by a horse walking on the canal towpath led by a crew member, often a child. Narrowboats were chiefly designed for carrying cargo, though there were some packet boats, carrying passengers, letters, and parcels. Source

November 12, 2007
In geometry, the tesseract, also called 8-cell or octachoron, is the four-dimensional analog of the (three-dimensional) cube, where motion along the fourth dimension is often a representation for bounded transformations of the cube through time. The tesseract is to the cube as the cube is to the square; or, more formally, the tesseract can be described as a regular convex 4-polytope whose boundary consists of eight cubical cells. Source

November 11, 2007
Frequency-hopping spread spectrum is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. Spread-spectrum signals are highly resistant to narrowband interference, difficult to intercept, and simply sounds like an increase in the background noise to a narrowband receiver. Spread-spectrum transmissions can share a frequency band with many types of conventional transmissions with minimal interference. As a result, bandwidth can be utilized more efficiently. The most celebrated invention of frequency hopping was that of actress Hedy Lamarr and composer George Antheil, who in 1942 received a patent for their "Secret Communications System." This early version of frequency hopping used a piano-roll to change between 88 frequencies, and was intended to make radio-guided torpedoes harder for enemies to detect or to jam. Source

November 10, 2007
The hot bulb engine or vaporizing oil engine is a type of internal combustion engine. It is a surface ignition engine in which the superheated fuel is ignited by being brought into contact with oxygen-rich, fresh air, rather than by a separate source of ignition, such as a spark plug. It was perfected by Herbert Akroyd Stuart in the end of the 19th century. Akroyd-Stuart's vaporizing oil engine (compared to spark-ignition) is distinctly different from Rudolf Diesel's better-known engine where ignition is initiated through the heat of compression. An oil engine will have a compression ratio of about 3:1, where a typical Diesel engine will have a compression ratio ranging between 15:1 to 20:1. Although popular for several years, the hot bulb engine was ultimately displaced by the diesel engine which is more versatile, achieves better efficiency and has a greater power-to-weight ratio. Source

November 9, 2007
A plugboard was a device used to direct the operation of unit record equipment, some cypher machines, and some early computers. They consisted of a number of plugs, or jacks, into which patch cords were inserted, completing a circuit. Wiring the plugboard "programmed" the system, which operated as a sort of read only memory. Control panels were first introduced in 1906 for the Hollerith-tabulated census, earlier machines had been hard wired for specific applications. Removable plugboards were introduced with the Hollerith (IBM) type 3-S tabulator in the 1920s. Different programs could be stored on separate plugboards, and then inserted into the tabulators as needed. A IBM control panel was roughly one to two feet (300 to 600 mm) on a side and had a rectangular array of holes or hubs. Pins at each end of a jumper wire were inserted into hubs, making a connection between two contacts on the machine when the control panel was placed in the machine, thereby connecting an emitting hub to an accepting hub. Source

November 8, 2007
Ladislao José Biro (1899 — 1985) is the inventor of the modern ballpoint pen. In 1938, while working as a journalist, he noticed that the ink used in newspaper printing dried quickly, leaving the paper dry and smudge-free. He tried using the same ink in a fountain pen but found that it would not flow into the tip, as it was too viscous. Working with his brother Georg, a chemist, he developed a new tip consisting of a ball that was free to turn in a socket, and as it turned it would pick up ink from a cartridge and then roll to deposit it on the paper. Bíró patented the invention in Paris in 1938. Ballpoint pens are still widely referred to as "a biro" in many European countries, including the UK, as well as Australia and New Zealand. Source

November 7, 2007
Wilhelm Conrad Röntgen (1845 – 1923) was a German physicist, of the University of Würzburg, who, on November 8, 1895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen rays, an achievement that earned him the first Nobel Prize in Physics in 1901. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 PHz to 30 EHz. X-rays are primarily used for diagnostic radiography and crystallography. X-rays are a form of ionizing radiation and as such can be dangerous. Source

November 6, 2007
Jonathan Edward Caldwell (born 1883, date of death unknown) was a self-taught aeronautical engineer who designed a series of bizarre aircraft and started public companies in order to finance their construction. None of these was ever successful, and after his last known attempt in the later 1930s he disappeared, apparently to avoid securities fraud charges. His name was later connected with mythical German flying saucers, and he remains a fixture of the UFO genre to this day. Source

November 5, 2007
The crystal radio receiver (also known as a crystal set) is a very simple kind of radio receiver. It needs no battery or power source except the power received from radio waves by a long outdoor wire antenna. Radio waves make radio wave electricity flow between the antenna wire and the ground wire. This electricity is connected to the crystal radio by the antenna and ground wire. The crystal radio uses a tuner to tune the electricity to receive just one station. The tuner can be as simple as an adjustable one-slider tuning coil that resonates with the antenna because the antenna also acts like a capacitor. Then it uses a crystal detector to convert this radio wave electricity back to sound electricity. The detector can be made from a special rock of galena in a holder. It uses earphones to convert the sound electricity to sound you can hear in the earphones. Source

November 4, 2007
The programmable metallization cell, or PMC, is a new form of non-volatile computer memory being developed at Arizona State University. PMC is one of a number of technologies that are being developed to replace the widely used flash memory, providing a combination of longer lifetimes, lower power, and better memory density. PMC is based on the physical re-location of metallic ions within a glassy solid electrolyte. A PMC memory cell is made of two solid metal electrodes, one tungsten the other silver or copper, with a thin film of the electrolyte between them, along with a control transistor. Additional metal ions are deposited within the electrolyte. Source

November 3, 2007
The cyclogyro is an aircraft design that uses airfoils rotating around a horizontal axis for both lift and thrust. They are theoretically capable of VTOL and hovering performance like a helicopter, but do not suffer from the helicopter's problems in high-speed forward flight. Although a number of cyclogyros were built in the 1930s, none are known to have successfully flown. The cyclogyro can be mistaken for different aircraft designs that used cylindrical wings that attempted to harness the Magnus effect. The cyclogyro wing looks similar to a paddle wheel, with airfoils replacing the paddles. The airfoils are individually adjustable in pitch, and are adjusted continually as the move around their axis. In normal forward flight the airfoils are given a slight positive pitch at the top of and forward portion of their arc, producing lift and forward thrust, negative pitch at the bottom, and are "flat" through the rest of the circle to produce little or no lift in other directions. The pitch can be adjusted to change the thrust profile, allowing the cyclogyro to travel in any direction. Source

November 2, 2007
In computing, an arithmetic logic unit (ALU) is a digital circuit that performs arithmetic and logical operations. The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers. The processors found inside modern CPUs and GPUs have inside them very powerful and very complex ALUs; a single component may contain a number of ALUs. Mathematician John von Neumann proposed the ALU concept in 1945, when he wrote a report on the foundations for a new computer called the EDVAC. Source

November 1, 2007
A turbo-electric transmission uses electric generators to convert the mechanical energy of a turbine into electric energy and electric motors to convert it back into mechanical energy to power the driveshafts. Turbo-electric drives are used in some locomotives and ships. The advantage of the turbo-electric transmission is that it allows the adaptation of high-speed turning turbines to the slow turning propellers or wheels without the need of a heavy and complex gearbox. A disadvantage shared with the more common diesel-electric powertrain is that because of the double conversion of mechanical energy to electricity and back more energy gets lost than with a mechanical transmission. Source

October 31, 2007
The Arecibo Observatory is a powerful radio telescope located in Puerto Rico. The Arecibo telescope is distinguished by its enormous size: the main collecting dish is 305 m in diameter, constructed inside the depression left by a karst sinkhole. The dish is the largest curved focusing dish on Earth, giving Arecibo the largest electromagnetic-wave gathering capacity. The Arecibo telescope's dish surface is made of 38,778 perforated aluminum panels, each measuring about 1 m by 2 m (3 ft by 6 ft), supported by a mesh of steel cables. It is operated by Cornell University under cooperative agreement with the National Science Foundation. The observatory is the largest single-aperture telescope ever constructed. It carries out three major areas of research: radio astronomy, aeronomy, and radar astronomy observations of solar system objects. Source

October 30, 2007
Raymond Scott (1908 – 1994), was an American composer, orchestra leader, pianist, engineer, recording studio maverick, and electronic instrument inventor. Though Scott never scored cartoon soundtracks, his music is familiar to millions because of its adaptation by Warner Brothers in over 120 classic Bugs Bunny and Daffy Duck animated features. Scott, who attended a technical high school in Brooklyn, was an early electronic music pioneer and adventurous sound engineer. During the 1930s and 1940s, many of his band's recording sessions found the bandleader in the control room, monitoring and adjusting the acoustics, often by revolutionary means. As well as designing novel instruments such as the Clavivox and Electronium, Scott recorded records of entirely electronic music. Source

October 29, 2007
Chicxulub Crater is an ancient impact crater buried underneath the Yucatán Peninsula, with its center located near the town of Chicxulub, Yucatán, Mexico. The crater is over 180 kilometers (112 mi) in diameter, and the asteroid or comet whose impact formed the crater was at least 10 km (6 mi) in diameter. The impact associated with the crater is implicated in causing the extinction of the dinosaurs as suggested by the K-T boundary, although some critics disagree that the impact was the sole reason, and also debate whether there was a single impact or whether the Chicxulub impactor was one of several that may have struck the Earth at around the same time. Recent evidence suggests that the impactor was a piece of a much larger asteroid which broke up in a collision more than 160 million years ago. Source

October 28, 2007
17P/Holmes is a periodic comet in our solar system discovered by the British amateur astronomer Edwin Holmes on November 6, 1892. Between October 23-24, 2007, the comet grew significantly brighter, going from magnitude 17 to magnitude 2.8 in just a few hours, while in the constellation of Perseus. The comet became easily visible to the naked eye as a bright yellow "star". Such luminosity bursts can normally be explained by sudden outgassing or the release of particles by the comet. Source

October 27, 2007
Pneumatics is the use of pressurized air to effect mechanical motion. Pneumatics is employed in a variety of settings. In dentistry applications, pneumatic drills are lighter, faster, and simpler than an electric drill of the same power rating (because the prime mover, the compressor, is separate from the drill and pumped air is capable of rotating the drill bit at extremely high rpm). Pneumatic transfer systems are employed in many industries to move powders and devices. Pneumatic tubes can carry objects over distances. Pneumatic devices are also used where electric motors cannot be used for safety reasons, such as deep in a mine where explosive dust or gases may be present. Source

October 26, 2007
The Saturn I was the United States' first dedicated "space launcher," a rocket designed specifically to launch loads into Earth orbit. Ten Saturn I's were flown by NASA, before it was replaced by the Saturn IB, which included a more powerful upper stage. The Saturn project was started in April 1957 as a heavy-lift concept designed by Wernher von Braun's team at the U.S. Army Ballistic Missile Agency. Source

October 25, 2007
Tanker 910 is the call-sign of the only wide-body jet air tanker currently in fire service. The aircraft, operated by 10 Tanker Air Carrier, is a converted McDonnell Douglas DC-10 aircraft used for fighting wildfires, typically in rural areas. The turbofan-powered craft carries up to 12,000 gallons (45,600 liters) of water or fire retardant in an exterior belly-mounted tank, which can be released in eight seconds. The water or retardant is carried in three center-line belly tanks. The tanks have internal baffles to prevent fluid shift (and consequent shift in center of gravity) while in flight, and sit with a 15 inches (38.1 cm) ground clearance. All three tanks can be filled simultaneously on the ground in eight minutes. The retardant is gravity-fed out of the tanks, and the entire load can be dumped in eight seconds, although the actual drop rate is computer controlled by the flight crew in order to produce the desired retardant spread over the fire lines. The aircraft is capable of applying a line of retardant 300 feet (91 m) wide by 1 mile (1.6 km) long. On October 22nd Tanker 910 became involved in the effort to put out California wildfires. Source

October 24, 2007
Harmony is the "utility hub" of the International Space Station. The hub contains four racks that provide electrical power, bus electronic data, and act as a central connecting point for several other components via its six Common Berthing Mechanisms. Weighing approximately 14,500 kilograms (31,967 lb), Harmony is the second of three connectors between the major ISS modules. Its deployment will expand the Space Station, allowing it to grow from the size of a three-bedroom house, to the space equivalent of a typical five-bedroom house, once the Japanese Kibō and European Columbus laboratories are attached. The Space Station robotic arm, Canadarm2, is able to operate from a powered grapple fixture on the exterior of Harmony. The node measures 7.2 meters (24 ft) in length, and it has a diameter of 4.4 meters (14 ft). Harmony was launched into space aboard Space Shuttle flight STS-120 on 23 October 2007. With the successful installation of Harmony NASA will declare the station "U.S. Core Complete". Source

October 23, 2007
The Solectria Sunrise was an innovative electric passenger car, designed to be as efficient as possible to produce long range from available battery technology. Created by Solectria Corporation of Woburn, Massachusetts, it was never put in to production beyond a few prototypes, although significant effort was made to make the design mass-produceable and it was even crash tested. The Sunrise is well known for having achieved a remarkable 375 miles on a single charge, during the 1996 Tour de Sol competition. In another notable achievement, the Sunrise was driven 217 miles from Boston to New York city "on a single battery charge, negotiating the everyday chaos of traffic, wrong turns and highway speeds up to 65 miles per hour". In 2005, a prototype and the moulds necessary to produce the composite chassis and body were sold off, and are now part of a hobbyist-led project to produce the vehicles as kits. A website with some pictures documenting the effort has appeared here: http://www.sunrise-ev.com Source

October 22, 2007
Tool substitution is when a tool can substitute for other tools, either as a make-shift solution or as a matter of practical efficiency. Often, by design or coincidence, a tool may share key functional attributes with one or more other tools. "One tool does it all" is a motto of some importance for workers who cannot practically carry every specialized tool to the location of every work task. Tool substitution may be divided broadly into two classes: substitution "by-design", or "multi-purpose" use, and substitution as make-shift. In many cases, the designed secondary functions of tools are not widely known. As an example of the former, many wood-cutting hand saws integrate a carpenter's square by incorporating a specially shaped handle which allows 90° and 45° angles to be marked by aligning the appropriate part of the handle with an edge and scribing along the back edge of the saw. The latter is illustrated by the saying "All tools can be used as hammers." Nearly all tools can be repurposed to function as a hammer, even though very few tools are intentionally designed for it. Source

October 21, 2007
The Gregorian calendar is the most widely used calendar in the world. A modification of the Julian calendar, it was first proposed by the Calabrian doctor Aloysius Lilius, and was decreed by Pope Gregory XIII, for whom it was named, in 1582. The Gregorian Calendar was devised both because the mean Julian Calendar year was slightly too long, causing the vernal equinox to slowly drift backwards in the calendar year, and because the lunar calendar used to compute the date of Easter had grown conspicuously in error as well. The Gregorian calendar system dealt with these problems by dropping a certain number of days to bring the calendar back into synchronization with the seasons, and then slightly shortening the average number of days in a calendar year, by omitting three Julian leap-days every 400 years. The days omitted are in century years which are not divisible by 400 (specifically: 29 February 1700, 1800, 1900; 2100, 2200, 2300; 2500, 2600, 2700; 2900, etc.). Source

October 20, 2007
Bronze is any of a broad range of copper alloys, usually with tin as the main additive. It was particularly significant in antiquity, giving its name to the Bronze Age. Although bronze develops a patina, it does not oxidize beyond the surface. It is considerably less brittle than iron and has a lower casting temperature. Copper-based alloys have lower melting points than steel and are more readily produced from their constituent metals. They are generally about 10 percent heavier than steel, although alloys using aluminium or silicon may be slightly less dense. Bronzes are softer and weaker than steel, bronze springs are less stiff (and so store less energy) for the same bulk. It resists corrosion (especially seawater corrosion) and metal fatigue better than steel and also conducts heat and electricity better than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than that of nickel-base alloys such as stainless steel. Another useful property of bronze is that it is non-sparking. That is, when struck against a hard surface, unlike steel, it will not generate sparks. Source

October 19, 2007
Oldowan is an anthropological designation for an industry of stone tools used by prehistoric homininans of the Lower Paleolithic. Oldowan tool use is estimated to have begun about 2.5 million years ago, lasting to as late as 1.5 million years ago. Oldowan tools were probably used for many purposes, which have been discovered from observation of modern apes and hunter-gatherers. Nuts and bones are cracked by hitting them with hammer stones on a stone used as an anvil. Heavy-duty tools could be used for woodworking, in the function of an axe. They were also invaluable for preparing hide. In addition, pointed bones or sticks were probably used for digging for roots and tubers. Source

October 18, 2007
A plank road or puncheon is a dirt path or road covered with a series of planks, similar to the wooden sidewalks one would see in a Western movie. Plank roads were wildly popular in the U.S. Northeast and U.S. Midwest in the first half of the 19th century. They were often built by turnpike companies. In the late 1840s plank roads inspired its own investment boom (and bust). The plank road boom had much in common with the Dot-com bubble: a new technology that promised to transform the way people lived and worked, permissive changes in legislation seeking to spur development, lots of investment by regular people, etc. Ultimately the technology failed to live up to its reputation and millions of dollars in investments evaporated almost overnight. Source

October 17, 2007
The Regency TR-1 was the first commercially produced portable transistor radio receiver. Announced on October 18th 1954 by the Regency Division of the Industrial Development Engineering Associates of Indianapolis, production started in November 1954. Over 150000 were sold at a price of $49.95 each. Source

October 16, 2007
Rolls Royce Trent is a family of high bypass turbofan engines manufactured by Rolls-Royce. Versions of the Trent are in service on the Airbus A330, A340, A380 and Boeing 777, and variants are in development for the forthcoming 787 and A350. The Trent has also been adapted for marine and industrial applications. Although all the engines in the Trent family share a similar layout, the three-spool configuration allows each engine module to be individually scaled to meet a wide range of performance and thrust requirements. Although inherently more complex, it results in a lighter, shorter, more rigid engine which suffers less performance degradation in service than an equivalent twin-spool. Source

October 15, 2007
Neutrinos are elementary particles that travel close to the speed of light, lack an electric charge, are able to pass through ordinary matter almost undisturbed, and are thus extremely difficult to detect. Neutrinos have a minuscule, but non-zero, mass too small to be measured as of 2007. Neutrinos are created as a result of certain types of radioactive decay or nuclear reactions such as those in the sun, in nuclear reactors, or when cosmic rays hit atoms. Most neutrinos passing through the Earth emanate from the sun, and more than 50 trillion solar electron neutrinos pass through the human body every second. Source

October 14, 2007
The Tesla turbine is a bladeless turbine design patented by Nikola Tesla in 1913. It is referred to as a bladeless turbine because it uses the boundary layer effect and not a fluid impinging upon the blades as in a conventional turbine. A Tesla turbine consists of a set of smooth disks, with nozzles applying a moving gas to the edge of the disk. The gases drag on the disk by means of viscosity and the adhesion of the surface layer of the gas. As the gas slows and adds energy to the disks, it spirals in to the center exhaust. Since the rotor has no projections, it is very sturdy. One of Tesla’s desires for implementation of this turbine was for geothermal power, which was described in "Our Future Motive Power". Source

October 13, 2007
The Bell X-1 was a joint NACA/US Air Force supersonic research project and the first aircraft to exceed the speed of sound in controlled, level flight. The X-1 was in principle a "bullet with wings" that closely resembled the shape of the Browning .50-caliber machine gun bullet that was known to be stable in supersonic flight. The aircraft was modified to feature an all-moving tailplane that allowed it to pass through the sound barrier safely. The pattern shape was followed to the point of removing a canopy. Instead, the pilot sat behind a sloped, framed window inside a confined cockpit in the nose. It was only 31 feet long with a 28-foot wingspan. On 14 October 1947 the tests culminated in the first manned supersonic flight, piloted by Air Force Captain Charles "Chuck" Yeager. Source

October 12, 2007
The Soyuz launch vehicle is an expendable launch system manufactured by TsSKB-Progress in Russia. It is used as the launcher for the manned Soyuz spacecraft as part of the Soyuz program. It is now also used to launch unmanned Progress supply spacecraft to the International Space Station and for commercial launches marketed and operated by TsSKB-Progress and the Centre Spatial Guyanais in French Guiana. Soyuz-U rockets are fueled with kerosene. The Soyuz launcher was introduced in 1966, deriving from the Vostok launcher. The production of Soyuz launchers reached a peak of 60 per year in the early 1980s. It has become the world's most used space launcher, flying over 1700 times, far more than any other rocket. It is a very old basic design, but is notable for low cost and very high reliability, both of which appeal to commercial clients. Source

October 11, 2007
In physics and fluid mechanics, a boundary layer is that layer of fluid in the immediate vicinity of a bounding surface. In the Earth's atmosphere the planetary boundary layer is the air layer near the ground affected by diurnal heat, moisture or momentum transfer to or from the surface. On an aircraft wing the boundary layer is the part of the flow close to the wing. The boundary layer effect occurs at the field region in which all changes occur in the flow pattern. The boundary layer distorts surrounding nonviscous flow. It is a phenomenon of viscous forces. Source

October 10, 2007
A turbosail is a naval propulsion system invented by Jacques-Yves Cousteau and used on the Alcyone. It consists of a vertical airfoil in the form of an ovoidal tube, with an adjustable flap. An aspiration system pulls air into the tubes, and is used to create pressure on one side of the sail; propulsion occurres perpendicularly to the pressure. In this way, the "sails" act as wings, with air moving slower on one side, creating lift. Standard engines can then be used in conjunction with the turbo sails. The efficiency of the system is not well documented. When the Alcyone was launched in 1985, it was suggested that tankers and other large vessels would soon install turbosails as a mean to decrease fuel consumption. The Alcycone reported a 1/3 fuel savings, and a larger commercial vessel had a 15% increase in fuel efficiency over a three year study. Source

October 9, 2007
Giant Magnetoresistance (GMR) is a quantum mechanical effect observed in thin film structures composed of alternating ferromagnetic and nonmagnetic metal layers. The 2007 Nobel Prize in physics was awarded to Albert Fert and Peter Grünberg for the discovery of GMR. The effect manifests itself as a significant decrease in resistance from the zero-field state, when the magnetization of adjacent ferromagnetic layers are antiparallel due to a weak anti-ferromagnetic coupling between layers, to a lower level of resistance when the magnetization of the adjacent layers align due to an applied external field. GMR has been used extensively in the read heads in modern hard drives. Another application of the GMR effect is in non-volatile, magnetic random access memory (MRAM). Source

October 8, 2007
FanWing is a concept for a type of aircraft. It is distinct from existing types of aircraft such as airplanes and helicopters in that it uses a fixed wing with a forced airflow produced by cylindrical fans mounted above the wing. Its makers claim it is the first horizontal-rotored integral lift and propulsion wing in history to sustain flight. FanWing is also the name of the company created to develop the concept. Source

October 7, 2007
A vertical-axis wind turbine is a machine that converts the kinetic energy in wind into mechanical energy. Unlike in the more typical horizontal-axis wind turbine, the vertical-axis type uses a main rotor shaft running vertically. Advantages of this arrangement are that the generator and can be placed at the bottom, near the ground, so the tower doesn't need to support it, and that the turbine doesn't need to be pointed into the wind. Drawbacks are usually pulsating torque that can be produced during each revolution and drag created when the blade rotates into the wind. It is also difficult to mount vertical-axis turbines on towers, meaning they must operate in the often slower, more turbulent air flow near the ground, resulting in lower energy extraction efficiency. Source

October 6, 2007
Tidal locking makes one side of an astronomical body always face another; for example, one side of the Earth's Moon always faces the Earth. A tidally locked body takes just as long to rotate around its own axis as it does to revolve around its partner. This synchronous rotation causes one hemisphere constantly to face the partner body. The change in rotation rate necessary to tidally lock two bodies is caused by the torque applied by gravity on bulges induced by tidal forces. This effect is employed to stabilize some artificial satellites. Source

October 5, 2007
Ambler's Texaco Gas Station, also known as Becker's Marathon Gas Station, is a historic filling station located at the intersection of Old U.S. Route 66 and Illinois Route 17 in the village of Dwight, Illinois, United States. The station has been identified as the longest operating gas station along Route 66; it last dispensed fuel in 1999. The station is a good example of a domestic style gas station and gets its most common names from ownership stints by two different men. Ambler's was the subject of major restoration work from 2005–2007, and reopened as a Route 66 visitor's center in May 2007. Ambler's Texaco Gas Station was added to the U.S. National Register of Historic Places in 2001. Source

October 4, 2007
The Voith-Schneider propeller, also known as a cycloid drive is a specialized marine propulsion system. It is highly maneuverable, being able to change the direction of its thrust almost instantaneously. From a circular plate, rotating around a vertical axis, a circular array of vertical blades (in the shape of hydrofoils) protrude out of the bottom of the ship. Each blade can rotate itself around a vertical axis. The internal gear changes the angle of attack of the blades in sync with the rotation of the plate, so that each blade can provide thrust in any direction, very similar to the collective pitch control and cyclic in a helicopter. Source

October 3, 2007
The 5AT Project is a plan to build a steam locomotive similar to the styles in use at the beginning of the 20th century, but incorporating modern manufacturing techniques and technology. According to the project website: "The 5AT is a totally new steam locomotive design, incorporating the latest proven steam locomotive technology, for hauling main line steam charter and railcruise trains. With a 70% increase in thermal efficiency over "classic" steam, and almost 3500 horsepower available at the cylinders, its perfomance will amply demonstrate what could have been achieved had steam locomotive development been fully exploited in the 20th Century." Source

October 2, 2007
An Electric Multiple Unit or EMU is a multiple unit train consisting of many carriages using electricity as the motive power. Some of the more famous Electric Multiple Units in the world are high speed trains: the Shinkansen in Japan, the TGV in France, and ICE 3 in Germany. EMUs are also popular on commuter and suburban rail networks around the world due to their fast acceleration, pollution free operation and quietness. Being quieter than Locomotive drawn trains, EMUs can operate later at night and more frequently without disturbing residents living near the railway lines. In addition tunnel design for EMU trains is simpler as provisions do not need to be made for diesel exhaust fumes. Source

October 1, 2007
A de Dion tube is an automobile suspension technology. It is a sophisticated form of non-independent suspension that uses universal joints at both the wheel hubs and differential, and uses a solid tubular beam to hold the opposite wheels in parallel. Unlike an anti-roll bar, a de Dion tube is not directly connected to the chassis nor is it intended to flex. In suspension geometry it is close to the trailing beam suspension most recently seen on the front wheel drive Chrysler "K-cars", but without the torsional flexibility of that suspension. De Dion tubes are generally considered exotic and are rarely used. A recent production vehicle using this suspension using an aluminum tube with leaf springs was the Ford Ranger EV. Rather than only a differential, an integrated drive component consisting of an AC electrical motor, 3:1 reduction, and differential action was mounted to the chassis. Source

September 30, 2007
The Shinkansen is a network of high-speed railway lines in Japan operated by Japan Railways. Since the initial Tōkaidō Shinkansen opened in 1964 running at 210 km/h (130 mph), the network (2,459 km or 1,528 miles) has expanded to link most major cities on the islands of Honshū and Kyūshū with running speeds of up to 300 km/h (188 mph), in an earthquake and typhoon prone environment. Test run speeds have been 443 km/h (275 mph) for conventional rail in 1996, and up to a world record of 581 km/h (361 mph) for maglev trainsets, in 2003. Source

September 29, 2007
The City & South London Railway is considered to be the first deep-level underground "tube" railway in the world. When first opened in 1890, it ran for a distance of 5.1 km in a pair of tunnels between the City of London and Stockwell, passing under the River Thames. The diameter of the tunnels restricted the size of the trains and the small carriages with their high backed seating were nicknamed "padded cells". The railway was later extended and became part of the London Underground system. Today, it forms part of the Bank branch of the Northern Line. The use of electricity to power trains had been experimented with in the previous decade and small scale operations had been implemented but the C&SLR was the first major railway in the world to adopt it as a means of motive power. The system operated using electric locomotives built by Mather & Platt collecting a current at 500 volts from the third rail and pulling a number of carriages. Source

September 28, 2007
A karez well system is an ancient water collection system made up of a horizontal series of wells and linked underground water canals that collects water from a watershed, usually surface runoff from the base of a mountain and channels the water to the surface, taking advantage of the current provided by the gravity of the downward slope. The canals are mostly underground to reduce water evaporation. Vertical wells are dug at various points to tap into the water current flowing down sloping land from the source, most frequently mountain runoff. The underground canals are built to connect the running water and channel it to the desired destination, usually an irrigation system for agricultural produce. Karez wells were used in many places but were most fully developed in Turfan, China, an important oasis stopover on the ancient Silk Route that owes its prosperity to the water provided by its karez well system. Source

September 27, 2007
The Harvest Moon is the full moon nearest to the autumnal equinox, which occurs in the northern hemisphere on or about September 23rd. All full moons rise around the time of sunset. However, although in general the moon rises about 50 minutes later each day, the Harvest Moon is special, because the time difference between moonrise on successive evenings around the full Harvest Moon is approximately 30 minutes. Thus there is no long period of darkness between sunset and moonrise around the time following these full moons. In times past this feature of these autumn moons was said to help farmers working to bring in their crops. They could continue being productive by moonlight even after the sun had set. Many cultures celebrate with gatherings, festivals, and rituals that are intricately attuned to the phase of the moon and the seasons. Source

September 26, 2007
The Seikan Tunnel is a 33.5 mile railway tunnel in Japan, with a 14.5 mile portion under the seabed. It travels beneath the Tsugaru Strait — connecting the island of Honshū and the island of Hokkaidō — as part of the Japan Railways Kaikyo Line. Although it is the longest railway tunnel in the world, faster and cheaper air travel has left the Seikan Tunnel comparatively underused. Surveying for the construction of the tunnel started in 1946. In 1971, 25 years later, construction began. First contact between the two sides was in 1983. Source

September 25, 2007
A hydraulic accumulator is an energy storage device. It is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure by an external source. That external source can be a spring, a raised weight, or a compressed gas. The main reasons that an accumulator is used in a hydraulic system are so that the pump doesn't need to be so large to cope with extremes of demand, so that the supply circuit can respond more quickly to any temporary demand and to smooth pulsations. Source

September 24, 2007
A diesel-hydraulic hybrid is a system for powering and propelling a vehicle similar to an electric hybrid, but using hydraulic components instead of electric. According to AutoblogGreen: "The diesel engine drives a hydraulic pump which draws fluid from a reservoir and pressurizes a high pressure accumulator. The accumulator acts as a power buffer, in a similar manner to a battery in an electric hybrid. The pressure from the accumulator is used to drive a hydraulic motor attached to the rear axle." This system is being tested by UPS in two prototype delivery vehicles, which have demonstrated a 40-70 percent reduction in fuel usage. Source

September 23, 2007
Turbinia was the first steam turbine powered steamship. Charles Algernon Parsons invented the steam turbine in 1884, and he had the Turbinia built as an experimental vessel in 1894. She was easily the fastest ship in the world at that time. Despite the success of the turbine engine, initial trials with one propeller were disappointing. After discovering the problem of cavitation and constructing the first cavitation tunnel, Parsons' research led to him fitting three axial flow turbines to three shafts, each shaft in turn driving three propellers. In trials this achieved a top speed of over 34 knots (63 km/h), so that "the passengers aboard would be convinced beyond all doubt Turbinia was Charles Parsons' winning North Sea greyhound". The vessel can still be seen at The Discovery Museum in Newcastle upon Tyne, England, while its original powerplant can be found at the London Science Museum. Source

September 22, 2007
The Thorr is an electric sports car being developed by Evisol in Europe. The Thorr uses an Siemens AC motor and inverter and Evisol plans to use Lithium Polymer batteries for a range of 240km. A video of the current version can be seen here. Source

September 21, 2007
Macadam is a type of road construction pioneered by the Scotsman John Loudon McAdam in around 1820. It consisted of creating three layers of stones laid on a crowned subgrade with side ditches for drainage. Although this method required a great deal of manual labor, it resulted in a strong and free-draining pavement. Roads constructed in this manner were described as "macadamized". With the advent of motor vehicles, dust became a serious problem on macadam roads. This problem was later rectified by spraying tar on the surface to create "tar-bound macadam" (tarmac). While macadam roads have now been resurfaced in most developed countries, some are preserved along stretches of roads such as the United States' National Road. Source

September 20, 2007
The Delta Queen is an American sternwheel steamboat. The Queen is 285 feet long, 58 feet wide, and draws 11.5 feet. The boat weighs 1,650 tons, with a capacity of 200 passengers. Its compound steam engine generates 2,000 ihp, powering a stern-mounted paddlewheel. The hull, first two decks and steam engines were ordered in 1924 from the William Denny & Brothers shipyard in Scotland. The Queen and her sister boat Delta King were shipped in pieces to Stockton, California in 1926. The Delta Queen currently cruises the Mississippi River and its tributaries on a regular schedule. The operator, Majestic America Line, recently announced that the Delta Queen would cease operations permanently at the end of the 2008 season. In September 2007, members of the Scottish Parliament, submitted a motion calling for the preservation of the ship. Source

September 19, 2007
The number zero is even. There are several equivalent ways to define what it means for an integer to be an even number, and zero satisfies all of these definitions. That zero is even is a necessary and consistent part of the general patterns obeyed by even and odd numbers. A number is called even if it is an integer multiple of 2. Zero is an integer multiple of 2, namely 0 × 2, so zero is even. Source

September 18, 2007
The Enigma machine was a cipher machine used to encrypt and decrypt secret messages. The Enigma was used commercially from the early 1920s on, and was also adopted by the military and governmental services of a number of nations—most famously by Nazi Germany before and during World War II. Like other rotor machines, the Enigma machine is a combination of mechanical and electrical systems. The mechanical mechanism consists of a keyboard; a set of rotating disks called rotors arranged adjacently along a spindle; and a stepping mechanism to turn one or more of the rotors with each key press. The exact mechanism varies, but the most common form is for the right-hand rotor to step once with every key stroke, and occasionally the motion of neighbouring rotors is triggered. The continual movement of the rotors results in a different cryptographic transformation after each key press. Source

September 17, 2007
Gold-aluminium intermetallics are intermetallic compounds of gold and aluminium that occur at contacts between the two metals. White plague is the name of the compound Au5Al2 as well as the problem it causes. It has low electric conductivity, so its formation at the joint leads to an increase of electrical resistance which can lead to total failure. Purple plague is a brittle, bright-purple compound of AuAl2. The process of the growth of the intermetallic layers leads to creation of voids in the metal lattice. These intermetallics have different properties than the individual metals which can cause problems in wire bonding in microelectronics. Source

September 16, 2007
The Facetmobile is a homebuilt aircraft designed by Barnaby Wainfan, a well known professional aerodynamicist and homebuilt aircraft expert. While only one Facetmobile prototype was produced, it has become well known due to its unique nature. The aircraft is somewhat of a cross between a lifting body and flying wing configuration - the whole aircraft is one low aspect ratio wing: a flat, angular lifting shape. Particularly notable is that the aircraft's shape is formed of a series of 11 flat surfaces, somewhat similar to the body of the F-117 Nighthawk jet strike aircraft, but without separate wing structures. The Facetmobile was designed prior to the public disclosure of the F-117 aircraft shape, and Wainfan claims that the visual similarity is coincidental, with very different engineering reasons (the F-117 uses flat panels for stealth technology, the Facetmobile for ease of construction). Source

September 15, 2007
The John Bull is an English-built railroad steam locomotive, operated for the first time on September 15, 1831; it became the oldest operable steam locomotive in the world (150 years) when the Smithsonian Institution operated it in 1981. Built by Robert Stephenson and Company, the John Bull was initially purchased by and operated for the Camden and Amboy Railroad, the first railroad built in New Jersey. The railroad rostered it as locomotive number 1 and used it heavily from soon after the railroad's construction in 1833 until 1866 when it was removed from active service and placed in storage. The locomotive became the world's oldest surviving operable steam locomotive when it ran again under its own power in 1981. Today, the original John Bull is on static display in the Smithsonian's National Museum of American History in Washington, DC. Source

September 14, 2007
Transfinite numbers are cardinal numbers or ordinal numbers that are larger than all finite numbers, yet not necessarily absolutely infinite. The term transfinite was coined by Georg Cantor, who wished to avoid some of the implications of the word infinite in connection with these objects, which were nevertheless not finite. Few contemporary workers share these qualms; it is now accepted usage to refer to transfinite cardinals and ordinals as "infinite". However, the term "transfinite" also remains in use. Source

September 13, 2007
The solar wind is a stream of charged particles which are ejected from the upper atmosphere of the sun. It consists mostly of high-energy electrons and protons that are able to escape the sun's gravity in part because of the high temperature of the corona and the high kinetic energy particles gain through a process that is not well understood at this time. Many phenomena are directly related to the solar wind, including geomagnetic storms that can knock out power grids on Earth, aurorae and the plasma tail of a comet always pointing away from the sun. Source

September 12, 2007
A sluice is a water channel that is controlled at its head by a gate. For example, a millrace is a sluice that channels water toward a water mill. A sluice gate is traditionally a wooden or metal plate which slides in grooves in the sides of the channel. Sluice gates are commonly used to control water levels and flow rates in rivers and canals. They are also used in wastewater treatment plants and to recover minerals in mining operations. Source

September 11, 2007
Burt Rutan is an American aerospace engineer noted for his originality in designing light, strong, unusual-looking, energy-efficient aircraft. He is most famous for his design of the record-breaking Voyager, which was the first plane to fly around the world without stopping or refueling, and the suborbital rocket plane SpaceShipOne, which won the Ansari X-Prize in 2004. Source

September 10, 2007
La Jamais Contente was the first vehicle to go over 100 km/h. It was an electric vehicle with light alloy torpedo shaped bodywork (although the high position of the driver and the exposed chassis below spoiled much of the aerodynamics). The land speed record was established, according to sources, on April 29 or May 1, 1899 at Achères, Yvelines near Paris, France. The vehicle had two direct drive Postel-Vinay 25 kW motors, running at 200 V drawing 124 Amperes, and was equipped with Michelin tires. Source

September 9, 2007
Mercedes Reaves is a Puerto Rican research engineer and scientist. She is responsible for the design of a viable full-scale solar sail and the development and testing of a scale model solar sail at NASA Langley Research Center in Virginia. Solar sails are a proposed form of spacecraft propulsion using large membrane mirrors. Radiation pressure is small and decreases by the square of the distance from the sun, but unlike rockets, solar sails require no fuel. Although the thrust is small, it continues as long as the sun shines and the sail is deployed. Source

September 8, 2007
The DHL Balloon is a giant helium balloon, located in the Downtown Core of Singapore. The distinctive red and yellow commercial passenger balloon is the world's largest tethered helium balloon. In April 2006, 40 crew members took 12 hours to inflate the French-made balloon, which took its first passengers in May 2006. As of September 2007, more than 150,000 people have ridden on the DHL Balloon, 70% of whom are tourists. Up to 1,000 people ride the balloon on weekends. The balloon measures 22 metres in diameter, and is filled with 6,500 cubic metres of helium. While it is the world's largest tethered helium balloon, it has been certified as an aircraft. There are only fifteen like it around the world. As the balloon is anchored to the ground with a metal cable, it only ascends and descends vertically to a maximum altitude of 150 metres. It can accommodate a maximum of 29 passengers in its gondola. Source

September 7, 2007
The production of renewable energy in Scotland is an issue that has come to the fore in technical, economic and political terms during the opening years of the 21st century. The natural resource base for renewables is extraordinary by European, and even global standards. In addition to an existing installed capacity of 1.3 Gigawatts of hydro-electric schemes, Scotland has an estimated potential of 36.5 GW of wind and 7.5 GW of tidal power, 25% of the estimated total capacity for the European Union and up to 14 GW of wave power potential, 10% of EU capacity. The renewable electricity generating capacity may be 60 GW or more, considerably greater than the existing capacity from all fuel sources of 10.3 GW. Much of this potential remains untapped, but continuing improvements in engineering are enabling more of the renewable resource to be utilised. Source

September 6, 2007
The Hutchison effect is a name given to a collection of alleged natural phenomena that John Hutchison claims to have discovered in 1979. According to Hutchison, while trying to duplicate experiments done by Nikola Tesla, he discovered a number of strange phenomena, including levitation, fusion of dissimilar materials, anomalous heating, spontaneous fracturing of metals, changes in the crystalline structure and physical properties of metals and the disappearance of metal samples. All these phenomena are jointly grouped under the name Hutchison Effect. Supporters like Mark Solis, his former webmaster, maintain that none can be the result of known physical phenomena, such as electromagnetism. Hutchison and his supporters surmise that these phenomena arise from zero-point energy or the Casimir effect. A great deal of controversy has arisen from Hutchinson's experiments and the accusations of fakery that have resulted. Source

September 5, 2007
In physics and engineering, including mechanical and electrical engineering, energy efficiency is a dimensionless number, with a value between 0 and 1 or, when multiplied by 100, is given as a percentage. Due to the principle of conservation of energy, energy efficiency within a closed system can never exceed 100%. The energy efficiency of a process is defined as the amount of mechanical work or energy released by the process divided by the quantity of work or energy used as input to run the process. Making homes, vehicles, and businesses more energy efficient is seen as a largely untapped solution to addressing global warming and energy security. Source

September 4, 2007
The eight-million-year-old cypresses are a 2007 paleontological discovery in northeastern Hungary of sixteen well-preserved swamp cypress trunks which were found in an open pit lignite mine 60 meters underground. The trunks, about 6 m high and 2–3 m in diameter, were cased in sand about 8 million years ago, preserving their wood without fossilization. The find is unique, since trees this old have never been found in their original state and original place before. The cypresses were 30 to 40 meters high and 300 to 400 years old when they died during the Miocene period, when the region was partially covered by the shallow Pannonian Sea with marshy shorelines creating habitat for swamp cypresses. The trees were covered by a sandstorm up to a height of 6 meters, and their trunks were preserved intact. Source

September 3, 2007
The Saffir-Simpson Hurricane Scale is a scale classifying most Western Hemisphere tropical cyclones that exceed the intensities of "tropical depressions" and "tropical storms", and thereby become hurricanes. The categories into which the scale divides hurricanes are distinguished by the intensities of their respective sustained winds. The classifications are intended primarily for use in measuring the potential damage and flooding a hurricane will cause upon landfall. The Saffir-Simpson Hurricane Scale is used only to describe hurricanes forming in the Atlantic Ocean and northern Pacific Ocean east of the International Date Line. Other areas label their tropical cyclones as "cyclones" and "typhoons", and use their own classification scales. Source

September 2, 2007
An ekranoplan is a vehicle resembling an aircraft but that operates solely on the principle of ground effect. Ground effect vehicles (GEV) fly above any flat surface, with the height above ground dependent upon the size of the vehicle. During the Cold War, ekranoplans were sighted for years on the Caspian Sea as huge, fast-moving objects. The name Caspian Sea Monster was given by US intelligence operatives who had spotted the huge vehicle, which looked like an airplane with the outer halves of the wings removed. After the end of the Cold War, the "monster" was revealed to be one of several Soviet military designs meant to fly only a few meters above water, saving energy and staying below enemy radar. The ekranoplan has a lifting power of 1,000 tonnes, among the largest ever achieved. The "Caspian Sea Monster" was over 100 m long (330 ft), weighed 540 tonnes fully loaded, and could travel over 400 km/h (250 mi/h), mere meters above the surface of the water. Source

September 1, 2007
The Vought XF5U-1 Flying Flapjack was an experimental U.S. Navy fighter aircraft designed by Charles H. Zimmerman during World War II. This unorthodox design consisted of a flat, somewhat disk-shaped body (hence its name) serving as the lifting surface. Two piston engines buried in the body drove propellers located on the leading edge at the wingtips. The disc wing design featured a low aspect ratio that overcame the built-in disadvantages of induced drag created at the wingtips with the large propellers actively cancelling the drag-causing tip vortices. The propellers were arranged to rotate in the opposite direction to the tip vortices, allowing the aircraft to fly with a much smaller wing area. The small wing provided high maneuverability with greater structural strength. Source

August 31, 2007
The Ćuk converter is a type of DC-DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude, with an opposite polarity. It uses a capacitor as its main energy-storage component, unlike most other types of converters which use an inductor. Due to the differences in the design from other types, such as the buck/boost converter, the Ćuk convertor is more expensive and less common. It is named after Slobodan Ćuk of the California Institute of Technology, who first presented the design. Source

August 30, 2007
A steam dummy, or dummy engine, was a steam engine enclosed in a wooden box structure made to resemble a railroad passenger coach. Steam dummies had some popularity in the first decades of railroading in the U.S., from the 1830s but passed from favor after the Civil War. It was thought that the more familiar appearance of a coach presented by a steam dummy, as compared to a conventional engine, would be less likely to frighten horses when these trains had to operate in city streets. Later it was discovered that it was actually the noise and motion of the operating gear of a steam engine that frightened horses, rather than the unfamiliar outlines of a steam engine. Many steam dummies were simply locomotives enclosed in coach's clothing, but some combined an actual railroad coach in the same body with the locomotive, creating an all-in-one vehicle that was a predecessor of later self-propelled rail cars, usually powered by electricity or petrol. Source

August 29, 2007
A sextant is a measuring instrument generally used to measure the angle of elevation of a celestial object above the horizon. Making this measurement is known as sighting the object, shooting the object or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart. A common use of the sextant is to sight the sun at noon to find one's latitude. Held horizontally, the sextant can be used to measure the angle between any two objects, such as between two lighthouses, which will, similarly, allow for calculation of a line of position on a chart. Source

August 28, 2007
The Quebec Bridge in Canada crosses the lower Saint Lawrence River. The bridge is a riveted steel truss structure and is 987 metres (3,239 feet) long, 29 m (94 ft) wide, and 104 m (340 ft) high. Cantilever arms 177 m (580 ft) long support a 195 m (640 ft) central structure, for a total span of 549 m (1800 ft), the longest cantilever bridge span in the world. The bridge accommodates three highway lanes, one rail line, and a pedestrian walkway. Source

August 27, 2007
Ship breaking or ship demolition involves breaking up of ships for scrap. Ship breaking is a type of recycling. Most ships have a life-span of a few decades before there is too much wear to make refit and repair practical. Ship breaking allows for materials from the ship, especially steel, to be given a new life in a new vessel. Until the late twentieth century, ship breaking took place in port cities in the "First World," including the United States. Today, however, most ship breaking yards are in developing nations, principally Bangladesh, China, and India, due to lower labor costs and less stringent environmental regulations dealing with the disposal of lead paint and other toxic substances. However, there are a few "breakers" in the United States that still operate. Currently, many ships are also sunk to make artificial reefs after being cleaned up. Source

August 26, 2007
A lunar eclipse occurs whenever the Moon passes through some portion of the Earth's shadow. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, the Moon is always full during a lunar eclipse. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes. The most recent total lunar eclipse was on 3 and 4 March 2007. The next one will occur on 28 August 2007. Read more about the upcoming eclipse in the Times-Standard. Source

August 25, 2007
The moment magnitude scale was introduced in 1979 as a successor to the Richter scale and is used by seismologists to compare the energy released by earthquakes. An increase of 1 step on this logarithmic scale corresponds to a 101.5 = 31.6 times increase in the amount of energy released, and an increase of 2 steps corresponds to a 103 = 1000 times increase in energy. The constants in the equation are chosen so that estimates of moment magnitude roughly agree with estimates using other scales, such as the Local Magnitude scale, ML, commonly called the Richter magnitude scale. One advantage of the moment magnitude scale is that, unlike other magnitude scales, it does not saturate at the upper end. That is, there is no particular value beyond which all large earthquakes have about the same magnitude. For this reason, moment magnitude is now the most often used estimate of large earthquake magnitudes. Source

August 24, 2007
Wave making resistance is a form of drag that effects surface watercraft, such as boats and ships, and reflects the energy required to push the water out of the way of the hull. This energy goes into creating the wake. For small displacement hulls, such as sailboats or rowboats, wave making resistance is the major source of drag. Calculations of wave making resistance are often used to compare potential speeds of displacement hulls. Source

August 23, 2007
The term 'planing' refers to a water craft which is predominantly supported by hydrodynamic lift, rather than hydrostatic lift (buoyancy). A planing boat's hull skims across the surface of the water rather than pushing through the water in the way a traditional displacement hull works. The term hydroplaning is sometimes used instead of planing. Planing allows the boat to go faster by using its speed and hull shape to lift the front part of the hull out of the water. The boat travels on top of the water, greatly reducing the hydrodynamic drag on the vessel. The increase in aerodynamic drag is small by comparison, and in sail boats can be compensated for by the increased power from the sails due to the faster speed of the craft, and by the crew trimming the sails. Source

August 22, 2007
Group theory is the branch of mathematics concerned with the study of groups. In abstract algebra, a group is a set with a binary operation that satisfies certain axioms, detailed below. Many of the structures investigated in mathematics turn out to be groups. These include familiar number systems, such as the integers, the rational numbers, the real numbers, and the complex numbers under addition, as well as the non-zero rationals, reals, and complex numbers, under multiplication. Other important examples are the group of non-singular matrices under multiplication and the group of invertible functions under composition. Group theory allows for the properties of such structures to be investigated in a general setting. Source

August 21, 2007
The belt alternator starter (or BAS), introduced by General Motors, is a mild hybrid system used in the 2007 Saturn VUE Green Line. It operates similar to the "start-stop" system used in the Chevrolet Silverado Hybrid in that it shuts down the engine when the vehicle comes to a stop and instantly restarts it when the brake pedal is released. The BAS system goes slightly further than the Silverado, however, in providing modest power assist for "acceleration feel", according to GM. Although not as effective as other systems, the BAS system is expected to provide about 20% fuel efficiency gain for the compact VUE. The system is reasonably simple and inexpensive, making the VUE Green Line the least expensive hybrid SUV available. One major benefit of the BAS technology is that it fits in the same space as a conventional engine. Source

August 20, 2007
Hydrodynamics, also known as liquid-dynamics in limited academic circles, (literally, "water motion") is fluid dynamics applied to liquids, such as water, alcohol, oil, and blood. However, this distinction from fluid dynamics as a whole is not always fully observed. Blaise Pascal in the 1600s contributed some of the initial theory to this field. The term originates from the work of Daniel Bernoulli, based on the title of his work called Hydrodynamica (1738). He and Leonhard Euler established the general equations of hydrodynamics. Source

August 18, 2007
In the mathematical field of numerical analysis, a Bézier curve is a parametric curve important in computer graphics. Generalizations of Bézier curves to higher dimensions are called Bézier surfaces, of which the Bézier triangle is a special case. Bézier curves were widely publicised in 1962 by the French engineer Pierre Bézier, who used them to design automobile bodies. The curves were first developed in 1959 by Paul de Casteljau using de Casteljau's algorithm, a numerically stable method to evaluate Bézier curves. Source

August 17, 2007
Pierre Jules César Janssen (1824–1907) was a French astronomer who along with the English scientist Sir Joseph Norman Lockyer is credited with discovering the gas helium. In 1868 Janssen discovered how to observe solar prominences without an eclipse. On August 18 of that same year, while observing an eclipse of the Sun in India, he noticed a bright yellow line with a wavelength of 587.49 nm in the spectrum of the chromosphere of the Sun. Janssen was at first ridiculed since no element had ever been detected in space before being found on Earth. On October 20 of the same year Lockyer also observed the same yellow line in the solar spectrum and concluded that it was caused by an unknown element after unsuccessfully testing to see if it were some new type of hydrogen. Source

August 16, 2007
Permutation is the rearrangement of objects or symbols into distinguishable sequences. Each unique ordering is called a permutation. For example, with the numerals one to six, each possible ordering consists of a complete list of the numerals, without repetitions. There are 720 total permutations of these numerals, one of which is: "4, 5, 6, 1, 2, 3". Source

August 15, 2007
The semaphore or optical telegraph is an apparatus for conveying information by means of visual signals, with towers with pivoting blades or paddles, shutters, in a matrix, or hand-held flags etc. Information is encoded by the position of the mechanical elements; it is read when the blade or flag is in a fixed position. In modern usage it refers to a system of signaling using two handheld flags. Other forms of optical telegraphy include ship flags, Aldis lamps, and Heliographs. Semaphore lines preceded the electrical telegraph. They were faster than post riders for bringing a message over long distances, but far more expensive and less private than the electrical telegraph lines which would replace them. Source

August 14, 2007
The Steel and Foam Energy Reduction (SAFER) barrier, sometimes called a soft wall, is a new technology found primarily on oval automobile race tracks and intended to make racing accidents safer. It was designed by a team of engineers at the University of Nebraska-Lincoln. The SAFER barrier consists of structural steel tubes welded together. Behind these tubes are bundles of closed-cell polystyrene foam, placed between the barrier and the concrete wall. The theory behind the design is that the barrier absorbs a portion of the kinetic energy released when a race car makes contact with the wall. This energy is dissipated along a longer portion of the wall, instead of propelling the car back into traffic on the track. Source

August 13, 2007
John Logie Baird (1888 – 1946) was a Scottish engineer and inventor of the world's first working television system. Although the development of television was the result of work by many inventors, Baird is one of its foremost pioneers and made major advances in the field. He is generally credited with being the first person to produce a live, moving television image in halftones by reflected light. In his first attempts to develop a working television system, Baird experimented with the Nipkow disk, and in February 1924 demonstrated to the Radio Times that a semi-mechanical analogue television system was possible by transmitting moving silhouette images, such as his fingers wiggling, in his London laboratory. On October 2, 1925 Baird successfully transmitted in his laboratory the first television picture with halftones: the head of a ventriloquist's dummy nicknamed "Stooky Bill" in a 30-line vertically scanned image, at five pictures a second. Baird went downstairs and fetched an office worker, 20-year-old William Edward Taynton, to see what a human face would look like, and Taynton became the first person to be televised in full tonal range. Source

August 12, 2007
Harry Brearley (1871 – 1948) is credited with the invention of "rustless steel", later to be called "stainless steel". Shortly before World War I, Brearley began to research new steels which could better resist the erosion of the internal surfaces of gun barrels caused by high temperatures. He began to examine the addition of chromium to steel, which was known to raise the material’s melting point, as compared to the standard carbon steels. Though Brearley left the Brown Firth Laboratories in 1915 the research continued under the direction of his successor, Dr. W. H. Hatfield. Hatfield is credited with the development, in 1924, of a stainless steel which even today is probably the widest-used alloy of this type, the so-called "18/8", which in addition to chromium, includes nickel (Ni) in its composition (18wt% Cr, 8wt% Ni). Source

August 11, 2007
In materials science, fatigue is the progressive and localised structural damage that occurs when a material is subjected to cyclic or fluctuating strains at nominal stresses that cause structural failure. The maximum values are often significantly less than the ultimate tensile stress, and may be below the yield stress of the material. Source

August 10, 2007
Eighteenmile Island is a 9.89 acre island on the Oregon side of the the Columbia River. It can be seen from Interstate 84, which runs along the Oregon side of the Columbia River, and from the historic Columbia River Highway. It was mostly barren as of 2007, but features several douglas firs and willows, a basalt cliff, wildflowers and a sandy beach. It is a few hundred feet from the Oregon side of the river, much closer than to the Washington side. The island's only structure is a private residence, a three-story wood-frame house built in 1968. A line from the mainland supplies electricity to the island; drinking water must be filtered from the Columbia. Eighteenmile Island is the only remaining privately owned island in the Columbia River. Source

August 9, 2007
Rudolf Diesel's first successful engine ran on its own power for the first time in Augsburg, Germany, on August 10, 1893. In remembrance of this event, August 10 has been declared "International Biodiesel Day". This engine stood as an example of Diesel's vision because it was powered by peanut oil — a biofuel. He believed that the utilization of biomass fuel was the real future of his engine. In a 1912 speech Diesel said, "the use of vegetable oils for engine fuels may seem insignificant today but such oils may become, in the course of time, as important as petroleum and the coal-tar products of the present time." Source

August 8, 2007
The Pennsylvania Trolley Museum, located at 1 Museum Road, Washington, Pennsylvania, is a museum dedicated to trolleys and includes several restored examples. According to their web site, the museum's mission is "to communicate the story of Pennsylvania's Trolley Era to a diverse audience through the preservation, interpretation, and use of its collection of electric railway and railroad equipment." To that end, the museum includes a collection of 45 refurbished trolleys. Source

August 7, 2007
The Warsaw radio mast was the world's tallest structure at 646.38 metres (2,120 feet) tall, until its collapse in 1991. It still remains the tallest land-based structure ever built. It was completed in 1974. The mast was insulated from the ground for a voltage of 120 kV, and so stood on a 2 metre high insulator. It operated as a mast radiator, so its height was chosen in order to function as a half-wavelength antenna for its broadcasting frequency. The signals from its 2 megawatt transmitters could be received across all of Europe, North Africa and even in North America. It was the only half wave radiator ever constructed for longwave broadcasting. Source

August 6, 2007
A barge is a flat-bottomed boat, built mainly for river and canal transport of heavy goods. Most barges are not self-propelled and need to be moved by tugboats towing or towboats pushing them. Barges are primarily used today for low value bulk items, as the cost of hauling goods by barge is very low. Barges are also used for very heavy or bulky items; a typical barge measures 195 feet by 35 feet (59.4 meters by 10.6 meters), and can carry up to 1500 tons of cargo. Source

August 5, 2007
Ethylene TetrafluoroEthylene (ETFE) is a fluorocarbon-based polymer plastic. It was designed to be a material with high corrosion resistance and strength over a wide temperature range. Ethylene-Tetrafluoroethylene is commonly used in the Nuclear Industry for tie or cable wraps. This is because ETFE exhibits excellent mechanical toughness and a chemical resistance that rivals Polytetrafluoroethylene (PTFE). In addition, ETFE exhibits a high-energy radiation resistance and can withstand moderately high temperatures for a long period of time. Source

July 27, 2007
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July 26, 2007
Freeman Dyson is an English-born American theoretical physicist and mathematician, famous for his work in quantum mechanics, solid-state physics, nuclear weapons design and policy, and for his serious theorizing in futurism and science fiction concepts, including the search for extraterrestrial intelligence. He is a lifelong opponent of nationalism, and proponent of nuclear disarmament and international cooperation. Dyson is a member of the Board of Sponsors of The Bulletin of the Atomic Scientists. Source

July 25, 2007
The Berlin U-Bahn, together with the S-Bahn, is the backbone of the public transport system of Berlin, Germany. The U-Bahn runs mostly underground (as U-Bahn stands for Untergrundbahn, or Underground railway), while the S-Bahn is mostly above ground. The U-Bahn opened in 1902 and now consists of 170 stations on nine lines, which have a total length of 91.25 miles (146km). About 90% of the total track length is underground. Trains run every two to five minutes during peak hours, and every seven to 12 minutes for the rest of the day. The entire system is maintained and operated by the Berliner Verkehrsbetriebe, commonly known as the BVG. Source

July 24, 2007
A velomobile or bicycle car is a human-powered vehicle, enclosed for protection from weather and collisions. They are virtually always single-passenger vehicles. They are derived from bicycles and tricycles, with the addition of a full fairing (aerodynamic shell). There are few manufacturers of velomobiles; many are homebuilt. Some models have the operator's head exposed; this has the advantage of giving the operator unobstructed vision, hearing, and some cooling, with the disadvantage of being more exposed to weather. When powered by an engine they are instead called microcars. Source

July 23, 2007
Machu Picchu is a pre-Columbian city created by the Inca Empire. It is located at 2,430 m on a mountain ridge in Peru. Forgotten for centuries by the outside world, although not by locals, it was brought back to international attention by archaeologist Hiram Bingham in 1911. The construction in Machu Picchu uses the classic Inca architectural style of polished dry-stone walls of regular shape. The Incas were masters of this technique in which blocks of stone are cut to fit together tightly without mortar. Many junctions in the central city are so perfect that not even a knife fits between the stones. Source

July 22, 2007
The Junkers Jumo 205 aircraft engine was the most famous of a series of diesel engines that were the first, and for more than half a century, the only successful diesel aircraft engines. The Jumo 204 first entered service in 1932. In all more than 900 of these engines were produced. These engines all used a two-stroke cycle with six cylinders and twelve pistons, in an opposed piston configuration with two crankshafts, one at the bottom of the cylinder block and the other at the top, geared together. Source

July 21, 2007
Napier Deltic is the name of both an opposed-piston high-speed diesel engine designed and produced by D Napier & Son, and locomotives produced by English Electric, using these engines, for British Railways. The original Napier Culverin engine was an opposed piston design. Instead of each cylinder having a single piston and being closed at one end with a cylinder head, the elongated cylinder contained two pistons moving in opposite directions toward the centre. This negates the need for a heavy cylinder head. This design resulted in a "flat" engine, intended to be buried in the wings of large aircraft. The Royal Navy required a much more powerful engine, so for the added power Napier took three of their original Culverins and "bolted them together". The result was an inverted triangle, the cylinder banks forming the sides, and tipped by three crankshafts, one at each corner of the triangle. The crankshafts were connected with phasing gears to drive one output shaft. Proving successful, the Deltic diesel engine became a common powerplant in small fast naval craft. Source

July 20, 2007
The Coandă-1910 was the first jet-propelled aircraft ever built. It was constructed by Romanian inventor Henri Coandă and exhibited by him at the Second International Aeronautical Exhibition in Paris around October 1910. The aircraft was quite unconventional in design, and its most striking feature was its powerplant: a kind of thermojet, a hybrid of jet engines and piston engine technology. This used an ordinary internal combustion engine to drive a compressor instead of a propellor. The compressed air was mixed with fuel and ignited in two combustion chambers before being exhausted along the sides of the aircraft. Source

July 19, 2007
Biodegradable plastics are plastics that will decompose in the natural environment. Biodegradation of plastics can be achieved by enabling microorganisms in the environment to metabolise the molecular structure of plastic films to produce an inert humus-like material that is less harmful to the environment. The main disadvantage with oil-based biodegradable plastics is that their degradation contributes to global warming through the release of carbon dioxide as a main end product. This does not apply to starch based plastics as they are formed from carbon which is already in the ecosystem (via photosynthesis). Another disadvantage with biodegradable plastic is that degradation occurs very slowly, if at all, in a sealed landfill. Also, biodegradable plastics cannot be mixed with other plastic sent for recycling: This damages the recycled plastic and reduces its value. Source

July 18, 2007
The Seven Bridges of Königsberg is a famous solved mathematics problem inspired by an actual place and situation. The city of Königsberg, Prussia is set on the Pregel River, and included two large islands which were connected to each other and the mainland by seven bridges. The question is whether it is possible to walk with a route that crosses each bridge exactly once. In 1736, Leonhard Euler proved that it was not possible. In the history of mathematics, Euler's solution of the Königsberg bridge problem is considered to be the first theorem of graph theory, which is now generally regarded as a branch of combinatorics. Source

July 17, 2007
Shuguang, also known as Project 714 was a manned spacecraft proposed by the People's Republic of China during the late 1960s and early 70s that was never built. The design was for a two-man capsule, similar to the American Gemini spacecraft, however, the Shuguang would have been lighter and smaller. Because of financial and political problems, Shuguang was cancelled on May 13, 1972. Source

July 16, 2007
The albumen print, invented in 1850 by Louis Désiré Blanquart-Evrard, was the first commercially exploitable method of producing a print on a paper base from a negative and became the dominant form of photographic positives from 1855 to the turn of the century. It used the albumen found in egg whites to bind silver nitrate and sodium chloride to the paper. The albumen seals the paper and creates a slightly glossy surface. A bath of sodium thiosulfate fixes the print’s exposure. Finally, gold toning improves the photograph’s tone and helps protect it from fading. Source

July 15, 2007
The coupe utility car body style, called "utilities" or "utes" for short, is a passenger-car derived cabin of "coupe" style with an integral cargo bed behind the cabin. Examples of this style include the Chevrolet El Camino and Ford Ranchero. Vehicles that uses this style are significantly different than a pickup truck, which has a cargo area separate from the cab. Holden coach works of Australia was the first to integrate a cargo area with the bodywork of a passenger vehicle in 1924, and the "ute" remains the mainstay variety of pickup truck in Australia. Source

July 14, 2007
The Holdridge life zones system is a global bioclimatic scheme for the classification of land areas. It was first published by Leslie Holdridge in 1947. It is a relatively simple system with the basic assumption that both soil and climax vegetation can be mapped once climate is known. The system has been shown to fit tropical vegetation zones, Mediterranean zones, and boreal zones, but is less applicable to cold oceanic or cold arid climates where moisture becomes the determining factor. The system has found a major use in assessing the possible changes in natural vegetation patterns due to global warming. Source

July 13, 2007
Mariner 4 was the fourth in a series of spacecraft used for planetary exploration and performed the first successful flyby of the planet Mars in 1964, returning the first pictures of the Martian surface. The Mariner 4 spacecraft consisted of an octagonal magnesium frame with four solar panels, solar pressure vanes, a high gain parabolic antenna and omnidirectional low gain antenna. At the bottom center of the spacecraft the television camera was mounted on a scan platform. The octagonal frame housed the electronic equipment, cabling, midcourse propulsion system, and attitude control gas supplies and regulators. Science instruments were a magnetometer, dust detector, cosmic ray telescope, trapped radiation detector, solar plasma probe, and ionization chamber/Geiger counter. Power was supplied by 28,224 solar cells which could provide 310 W at Mars. A rechargeable 1200 Wh silver-zinc battery was also used for maneuvers and backup. Source

July 12, 2007
The Gurney Flap is a small flat tab projecting from the trailing edge of a wing. Typically it is set at a right angle to the pressure side surface of the airfoil, and projects 1% to 2% of the wing chord. This trailing edge device can improve the performance of a simple airfoil to nearly the same level as a complex high-performance design. The device operates by increasing pressure on the pressure side, decreasing pressure on the suction side, and helping the boundary layer flow stay attached all the way to the trailing edge on the suction side of the airfoil. Common applications occur in auto racing, helicopter horizontal stabilizers, and aircraft where high lift is essential, such as banner-towing airplanes. Source

July 11, 2007
Telstar was the first active communications satellite (launched in 1962), and the first satellite designed to transmit telephone and high-speed data communications. It was roughly spherical, was 34.5 inches long, and weighed 170 pounds. Its outer surface was covered by solar cells in order to always receive some power. Telstar was equipped with a helical antenna which received microwave signals from a ground station, then amplified and rebroadcast the signal. The day before Telstar was launched, the United States tested a high-altitude nuclear device which super-energized the Earth's Van Allen Belt where Telstar took orbit. This vast increase in radiation overwhelmed Telstar's fragile transistors; it went out of service in early December, but was restarted in early January of 1963. Due to futher transistor failures, it went out of service on February 21, 1963. According to US Space Objects Registry, Telstar 1 is still in orbit above the earth. Source

July 10, 2007
A Versorium is a device for detecting the presence of static electricity and the first known electrical device. It was developed in 1600 by William Gilbert, physician to Queen Elizabeth I. The versorium is a needle constructed out of metal which is allowed to pivot freely on a pedestal, similar to a compass. The metal needle would be attracted to charged bodies brought near it, turning towards the charged object. At the time, the differences between magnetic and electrical forces were poorly understood and Gilbert did a series of experiments to prove they were two separate types of forces with the Versorium and another device called a Terrella (or "little Earth"). In fact, Gilbert was the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity - one might call him the first electrical engineer. Source

July 9, 2007
Luxtorpeda was a common name of a famous Polish train, which ran on some of the most important rail routes of Poland in the 1930s. A luxtorpeda consisted of a single, first-class only rail car, with its own diesel engine. Luxtorpedas looked like a hybrid between a limousine and a bus. Diesel engines were used instead of gasoline due to lower fuel cost, and a lower fire/explosion risk. The engines were mounted at each end of the car, just in front of the driving cabin. The maximum practical operational speed was 100–105 km/h. Due to the lack of buffers and couplings it was impossible to join cars together, or to attach such a car to an ordinary locomotive; they always traveled as separate units. Source

July 8, 2007
The Boeing 787 Dreamliner is a mid-sized, wide-body, twin engine jet airliner currently in production by Boeing's Commercial Airplanes division and scheduled to enter service in May 2008. It will carry between 210 and 330 passengers depending on variant and seating configuration. Boeing has stated that it will be more fuel-efficient than earlier Boeing airliners. It will also be the first major airliner to use composite material for most of its construction. Source

July 7, 2007
z/OS (or zero-downtime/OS) is a 64-bit server operating system from IBM. It is the successor to the IBM mainframe operating system OS/390. While much of the functionality originated in the 1970s and (in some cases) 1960s, z/OS now includes much of the same attributes and elements of other currently-available open systems. z/OS is IBM's flagship operating system, suited for continuous, high volume operation with high security and stability. One of the most common applications used with z/OS is CICS, a transaction server used in bank teller applications, airline reservation systems, ATM systems, etc. Source

July 6, 2007
The Sundial Bridge is a cantilever spar cable-stayed bridge that spans the Sacramento River in Redding, California. It was designed by Santiago Calatrava and completed in 2004. The Sundial Bridge is unique because it does not use a symmetrical arrangement of cables on each side of the tower; instead it uses an angled cantilever tower loaded by cable stays on only one side. This requires that the spar resist bending and torsional forces and that its foundation resists overturning. This pedestrian bridge features a single 217 foot (66 meter) mast that serves as the gnomon of the world's largest sundial. Source

July 5, 2007
Nash Timbers is a global and domestic distributor of timber flooring, joinery and beams. The company is based in Sydney, Australia and was founded in 2003 by David Nash. The company is notable for its stance on green timber and its role as a major informant to key industry figures concerning the origin and proper use of wood products including promoting the use of timber through sustainable methods such as recycling. Nash Timbers' stance on environmental sustainability has been of notable importance in leading the industry in a "greener" direction. Source

July 4, 2007
Charles Lutwidge Dodgson (January 27, 1832 – January 14, 1898), better known by the pen name Lewis Carroll, was an English author, mathematician, logician, Anglican clergyman and photographer. His most famous writings are Alice's Adventures in Wonderland and its sequel Through the Looking-Glass as well as the poems "The Hunting of the Snark" and "Jabberwocky", all considered to be within the genre of literary nonsense. His facility at word play, logic, and fantasy has delighted audiences ranging from children to the literary elite, and beyond this his work has become embedded deeply in modern culture, directly influencing many artists. Source

July 3, 2007
Number 4468 Mallard is a London and North Eastern Railway Class A4 4-6-2 Pacific steam locomotive designed by Sir Nigel Gresley and built at Doncaster, England in 1938. It was designed as an express locomotive with a wind-tunnel-tested, aerodynamic body that allowed it to reach speeds of over 100 mph (160 km/h). It was in service until 1963 when it was retired, having covered almost one and a half million miles (2.4 million km). Mallard is now part of the National Collection at the United Kingdom's National Railway Museum in York. Mallard is 70 ft long and weighs 165 tonnes, including the tender. Mallard is the holder of the world speed record for steam locomotives at 126 mph (203 km/h). Mallard was the perfect vehicle for such an endeavor, being one of the A4 class of streamlined locomotives designed for sustained 100+ mph (160 km/h) running. Source

July 2, 2007
Steam rail motors were self-propelled passenger carriages operated by the Great Western Railway in England and Wales from 1903 to 1935. They incorporated a steam locomotive within the body of the carriage. The rail motors were used to stimulate traffic on branch lines, where small and cheap platforms could be built to serve small traffic sources. They also operated frequent services in an attempt to fight off competition from new electric tramways. On some services they proved so successful that they could not cope with the number of passengers wishing to travel and so extra coaches were needed, but the lightweight rail motors could not cope with pulling trailers on hilly lines. There were also problems encountered with maintaining the rail motors in dirty engine sheds, while keeping the passenger sections clean. Source

July 1, 2007
A steam donkey is a type of stationary steam engine, constituted of frame, a boiler, and at least one winch. These engines were used historically during logging operations to haul logs in almost every imaginable setting and circumstance, but they were most commonly used in yarding, skidding, & loading. Logs were pulled with a wire cable attached to a winch. They were also known as donkey engines, and were so named because of the animals they replaced. John Dolbeer (1827-1902) of Crescent City, California, invented the donkey engine in August of 1881. On Dolbeer's first model, he wrapped a 150-foot, 4½ inch manila rope several times around a gypsy head (vertically mounted spool) and attached the other end to a log. The donkey pulled the log toward the engine. The engine was moved by attaching the line to tree and pulling it along on its log skids. Source

June 30, 2007
A commutator is an electrical switch that periodically reverses the current in an electric motor or electrical generator. The setting of the switch is tied to the motors axis of rotation which allows the coil to maintain a magnetic field whose direction is roughly fixed while still allowing the coil to rotate freely. The operation of DC motors relies on the fact that in the presence of a properly aligned fixed external magnetic field the coil will feel a roughly constant torque in one direction. A commutator typically consists of a set of copper contacts, fixed around the circumference of the rotating part of the machine (the rotor), and a set of spring-loaded carbon brushes fixed to the stationary part of the machine (the stator) that complete the electrical circuit from the rotor's windings to the outside of the machine. Source

June 29, 2007
Special relativity is a theory that explores the physical consequences of the relationship between space and time. The special theory of relativity was first put forward by Einstein in 1905 but this has now been replaced by a slightly different approach that is more fundamental than Einstein's original theory. The modern approach depends upon the concept of a four-dimensional universe. This approach uses the concept of invariance to explore the types of coordinate systems that are required to provide a full physical description of the location and extent of things. Source

June 28, 2007
The Ashden Awards for Sustainable Energy are annual awards given by a charity of the same name that is based in London. They reward and promote excellent local sustainable energy solutions in the UK and developing countries that protect the environment, and improve quality of life. By rewarding the best, they aim to raise awareness of the huge potential of local sustainable energy to both tackle climate change and improve the quality of people's lives. Source

June 27, 2007
The Solar Electric Light Company or SELCO is a company based in Bangalore, India. The main goal of this company is to provide reliable, affordable, and environmentally sustainable electricity to homes and businesses, especially in rural areas. The company has won the Ashden Awards (also known as the Green Oscars) twice, once in 2005 and the other in 2007. SELCO was formed in the year 1995 by an entrepreneur named Harish Hande who got the inspiration to start this company while studying energy engineering at the University of Massachusetts at Lowell. Source

June 22, 2007
DVD ("Digital Versatile Disc" or "Digital Video Disc") is an optical disc storage media format that can be used for data storage, including movies with high video and sound quality. DVDs resemble Compact Discs in that they have the exact size and appearance, and both are optical storage media so similar that a dvd reader or writer can usually read CDs, but DVDs are encoded in a different format of much greater density, allowing a data storage capacity 8 times greater. Source

June 20, 2007
SpaceShipOne is an experimental spaceplane developed by Scaled Composites to carry three humans in a sea-level pressurised cabin to an altitude in excess of 100 km and reenter the atmosphere to land on a standard runway. The fuselage is cigar-shaped, with an overall diameter of about 1.5 m. The main structure is of a graphite/epoxy composite material. The craft has short, wide wings, with large vertical tailbooms mounted on the end of each wing, and horizontal stabilisers protruding from the tailbooms. The overall mass of the fully-fuelled craft is 3600 kg, of which approximately 270 kg is fuel and 1400 kg is oxidiser. SpaceShipOne completed the first privately funded human spaceflight on June 21, 2004. Source

June 19, 2007
New York congestion pricing is a proposed traffic congestion fee for vehicles traveling into or within the Manhattan central business district of New York City. The congestion pricing charge is one component of New York City Mayor Michael Bloomberg's plan to improve the city's future environmental sustainability while planning for population growth, entitled PlaNYC 2030: A Greener, Greater New York. If approved and implemented, it would be the first such fee scheme enacted in the United States. Source

June 18, 2007
The Pioneer Zephyr is a diesel-powered railroad train built in 1934 for the Chicago, Burlington and Quincy Railroad. The train featured extensive use of stainless steel and included innovations such as shotwelding (a specialized type of spot welding) to join the stainless steel, and articulation to reduce its weight. On May 26, 1934 it set a speed record for travel between Denver, Colorado, and Chicago, Illinois, when it made a 1,015-mile (1,633 km) non-stop "Dawn-to-Dusk" dash in 13 hours 5 minutes at an average speed of 77 mph (124 km/h). For one section of the run it reached a speed of 112.5 mph (181 km/h), just short of the then US land speed record of 115 mph (185 km/h). The historic dash inspired two films and the train's nickname, "Silver Streak". The train entered regular revenue service on November 11, 1934 between Kansas City, Missouri, Omaha and Lincoln, Nebraska. It operated this and other routes until its retirement in 1960, when it was donated to Chicago's Museum of Science and Industry, where it remains on public display. Source

June 16, 2007
For magnetic materials, saturation is the state when the material cannot absorb a stronger magnetic field, such that an increase of magnetization force produces no significant change in magnetic flux density. Saturation limits the minimum size of transformer cores. To lower its effects, an air gap is created in some kinds of transformer cores. This condition also exists in electric motors, which must be accounted for in their design. Source

June 15, 2007
A train ferry is a ship designed to carry railway vehicles. Typically, one level of the ship is fitted with railway tracks, and the ship has a door at the front and/or rear to give access to the wharves. The wharf has a ramp or linkspan that connects the railway proper to the ship, allowing for the water level to rise and fall with the tides. While railway vehicles can be and are shipped on the decks or in the holds of ordinary ships, purpose-built train ferries are much quicker to load and unload, especially as several vehicles can be loaded or unloaded at once. Source

June 14, 2007
Balto was a Siberian Husky sled dog who led his team on the final leg of the 1925 serum run to Nome, in which diphtheria antitoxin was transported from Anchorage, Alaska to Nome by dog sled to combat an outbreak of the disease. The run is commemorated by the annual Iditarod Trail Sled Dog Race. Balto was named after the Sámi explorer Samuel Balto. Source

June 13, 2007
The Mercedes-Benz 260 D was the first diesel engined production passenger car and was made from 1936 to 1939. The car had a 2545 cc overhead valve, 4 cylinder engine with a Bosch diesel injection system and produced 45 BHP at 3000 RPM. The car weighed approximately 1600 kg and could reach a top speed of 95 km/h. A three speed gearbox with overdrive was fitted and it gained synchromesh on all ratios from 1938. The 260 D demonstrated the fuel economy of the diesel engine and facilitated the future success of the diesel powered passenger car. Source

June 12, 2007
Weather lore is the body of informal folklore related to the prediction of the weather. It has been a human desire for millennia to make accurate weather predictions. Oral and written history is full of rhymes, anecdotes, and adages meant to guide the uncertain in determining whether the morrow will bring weather fair or foul. For the farmer wanting to plant his crop, for the merchant about to send his ships on trade, foreknowledge of tomorrow's circumstances might mean the difference between success and failure. Prior to the invention of the mercury barometer, it was very difficult to gather numerical data of any predictive value. Even though there were devices such as the weather stick which gave some indication of moisture changes, the only instrument of any reliability was human experience. Source

June 11, 2007
The Gossamer Albatross was a human-powered aircraft that successfully crossed the English Channel on June 12, 1979. The aircraft was powered using pedals to drive a large two-bladed propeller. Piloted by amateur cyclist Bryan Allen it completed the 35.8 km (22.2 mi) crossing in 2 hours and 49 minutes, achieving a top speed of 29 km/h (18 mph) and an average altitude of 1.5 metres (5 feet). The empty mass of the structure was only 32 kg (71 lb), although the gross mass for the Channel flight was almost 100 kg (220 lb). To maintain the craft in the air it was designed with very long tapering wings (high aspect ratio), like those of a glider, allowing the flight to be undertaken with a minimum of power. In still air the required power was on the order of 0.3 horsepower (200 W), though even mild turbulence made this figure rise rapidly. Source

June 10, 2007
The Eliica (or the Electric Lithium-Ion Car) is a battery electric vehicle designed by a team at Keio University in Tokyo. The car runs on a lithium-ion battery and can accelerate from 0-100 km/h (60 mph) in four seconds. In 2004, the Eliica reached a speed of 370 km/h (230 mph) on Italy's Nardo High Speed Track. The team's goal is to exceed 400 km/h (250 mph), breaking the record set by today's street-legal gasoline-powered vehicles. The body of the four door car has a futuristic, bullet shape design which was tested in a wind tunnel. The car's platform contains 4 tracks of 80 batteries, which make for one third of the vehicle's cost. They currently require about 10 hours of recharging from empty to full charge, and can be easily charged off of a residential power grid. Source

June 9, 2007
Pocket gophers are burrowing rodents found in North America and extending into Central America. Gophers are heavily built, and most are moderately large, weighing a few hundred grams. All pocket gophers are burrowers and their cheek pouches are used for transporting food back to their burrows. Their presence is announced by the appearance of mounds of fresh dirt about 20 cm in diameter. These mounds will often appear in vegetable gardens, lawns, or farms, as gophers like moist soil. They also enjoy feeding on vegetables. Pocket gophers, despite being largely a pest, are a symbol of the U.S. state of Minnesota, sometimes called "The Gopher State". Source

June 8, 2007
Television is a widely used telecommunication system for broadcasting and receiving moving pictures and sound over a distance. The term may also be used to refer specifically to a television set, programming or television transmission. Since it first became commercially available from the late 1930s, the television set has become a common household communications device in homes and institutions as a source of entertainment and news. Source

June 7, 2007
The Speech Accent Archive is a linguistics project at George Mason University that has created a catalog of human accents. The project's website describes their archive as a teaching and research tool. The archive is composed of recordings of people of various backgrounds speaking the same paragraph of text in English. The Speech Accent Archive can be found here.

June 6, 2007
In camera design, a focal-plane shutter is a type of photographic shutter. It is so called because it is right in front of the focal (film) plane of the camera. One of the main advantages of focal-plane shutters is that the shutter can be built into the body of a camera which accepts interchangeable lenses, eliminating the need for each lens to have a central shutter built into it. The focal-plane shutter is also a fairly simple mechanism which is capable of quite fast and accurate shutter speeds. Source

June 5, 2007
The Peugeot Scoot'Elec is an electric motor scooter produced by Peugeot in France. Launched in 1996, it is powered by a 2.8kW DC motor fed from 3 Saft nickel-cadmium monoblocs giving an 18V 100Ah battery. Built around a "double cradle", the frame holds the batteries low down between and behind the rider's feet, providing a very low centre of gravity. The electronic controller and onboard charger are housed under the seat. The scooter weighs 115 kg (254 lb). It has a nominal range of 40 km (25 miles) at 45 km/h (30 mph), but this can be extended by using economy mode, which limits the speed to 30 km/h (20 mph). Source

June 4, 2007
Computer programming is the process of writing, testing, and maintaining the source code of computer programs. The source code is written in a programming language. This code may be a modification of existing source or something completely new, the purpose being to create a program that exhibits the desired behavior. The use of microprocessors in many common devices has made computer programming important in many different fields of manufacturing and engineering. Even the simplest, most common household items often contain a computer chip with some form of programming intrinsic to its function. Source

June 2, 2007
The Curta was a small, hand-cranked mechanical calculator introduced in 1948. It had an extremely compact design, a small cylinder that fit in the palm of the hand. It could be used to perform addition, subtraction, multiplication, division, and, with more difficulty square roots, and other operations. The Curta's design is a variant of Gottfried Leibniz's Arithmometer, accumulating values on cogs, which are added or complemented by a stepped drum mechanism. Source

June 1, 2007
Lean burn is an internal combustion of lean air-fuel mixtures. It happens at very high air-fuel ratios (up to 65:1), so the mixture has considerably less amount of fuel in comparison to stoichiometric combustion ratio (14.7 for petrol). The engines designed for lean burning can employ higher compression ratios and thus provide better performance, efficient fuel use and low exhaust emissions than those found in conventional petrol engines. The main drawback of lean burn engines is that they do not work well with modern 3-way catalytic converters. However, using various techniques to overcome this problem, many manufactures have used and continue to produce vehicles that employ lean burn. Also, all diesel engines are lean burning, due to the nature of the diesel combustion cycle. Source

May 30, 2007
A power take-off, usually refered to as a PTO is a splined driveshaft, usually on a tractor or truck that can be used to provide power to an attachment or separate machine. It is designed to be easily connected and disconnected. The power take-off allows implements to draw energy from the tractor's engine. A similar concept, also called a PTO, is found on the GE Electrak electric garden tractor. On the Electrak, the PTO is a electrical connection for powering accessories, such as a mower or tiller. Source

May 29, 2007
The eBox is a conversion of a Scion xB vehicle into a battery electric vehicle produced by the U.S. company AC Propulsion. The prototype eBox was unveiled in Santa Monica, CA on August 18, 2006. The prototype used a battery pack consisting of 5,300 Li-ion cells arranged into 100 blocks of 53 cells each. The first production eBox was delivered to actor Tom Hanks on February 15, 2007. AC Propulsion offers the conversion for USD $55,000, in addition to the base vehicle cost. Source

May 28, 2007
Chain drive is a way of transmitting mechanical power from one place to another. It is often used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles. Most often, the power is conveyed by a roller chain, known as the drive chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. Source

May 27, 2007
A flywheel is a rotating disk used as a storage device for kinetic energy. Flywheels resist changes in their rotational speed, which helps steady the rotation of the shaft when a fluctuating torque is exerted on it by its power source such as a piston-based engine, or when the load placed on it is intermittent. Flywheels can be used to produce very high power pulses as needed for some experiments. Recently, flywheels have become the subject of extensive research as power storage devices for uses in vehicles. Source

May 26, 2007
An electrolyte is a substance containing free ions that behaves as an electrically conductive medium. Because they generally consist of ions in solution, electrolytes are also known as ionic solutions, but molten electrolytes and solid electrolytes are also possible. Electrolytes commonly exist as solutions of acids, bases or salts. Furthermore, some gases may act as electrolytes under conditions of high temperature or low pressure. Electrolyte solutions can also result from the dissolution of some biological and synthetic polymers. Source

May 25, 2007
Kinetic art is sculpture that contains moving parts. The moving parts are generally powered by wind, a motor or the observer's hand. The Kinetic Sculpture Race has been an annual event in Ferndale, California since 1969. In this context, kinetic sculptures are cross-country, human-powered vehicles made to go on sand, water, pavement and other surfaces encountered on the annual 3-day event on Memorial Day weekend in Humboldt County, California. Source

May 24, 2007
Towel Day is celebrated every May 25 as a tribute by fans of the late author Douglas Adams. The commemoration was first held in 2001, two weeks after his death on May 11, and since then has been extended to an annual event. On this day, fans carry a towel with them throughout the day. The towel is a reference to Adams's popular science fiction comedy series The Hitchhiker's Guide to the Galaxy. Source

May 23, 2007
A fastener is a hardware device that mechanically joins or affixes two or more objects together. Fasteners can also be used to close a container such as a bag, a box, or an envelope. Fasteners used in these manners are often temporary, in that they may be fastened and unfastened repeatively. Some types of woodworking joints make use of separate internal reinforcements, such as dowels or biscuits. Other alternative methods of joining materials include crimping, welding, soldering, brazing, taping, gluing, cementing, or the use of other adhesives. The use of force may also be used, such as with magnets, vacuum (like suction cups), or even friction. Source

May 22, 2007
Hydropower is the capture of the energy of moving water for some useful purpose. Prior to the widespread availability of commercial electric power, hydropower was used for irrigation, milling of grain, textile manufacture, and the operation of sawmills. Today the largest use of hydropower is for electric power generation, which allows low cost energy to be used at long distances from the watercourse. Micro-hydro power has been increasingly used as an alternative energy source, especially in remote areas where other power sources are not viable. Small scale hydro power systems can be installed in small rivers or streams with little or no discernible environmental effect on things such as fish migration. Most small scale hydro power systems make no use of a dam or major water diversion, but rather use water wheels. Source

May 21, 2007
The Geysers geothermal power field spans an area of around 30 square miles in Sonoma and Lake counties in California. It is the largest geothermal development in the world, currently outputting over 750 MW. The Geysers consists of 21 separate power plants that utilize steam from more than 350 producing wells. Power from The Geysers provides electricity to Sonoma, Lake, Mendocino, Marin, and Napa counties. It is estimated that the development meets 60 percent of the power demand for the coastal region between the Golden Gate Bridge and the Oregon state line. Source

May 20, 2007
Geothermal power is the use of geothermal heat to generate electricity. Three types of power plants are used for geothermal power: dry steam, flash, and binary. Dry steam plants take steam out of fractures in the ground and use it to directly drive a turbine. Flash plants take hot water out of the ground, and allows it to boil as it rises to the surface then runs the steam through a turbine. In binary plants, the hot water flows through heat exchangers, boiling an organic fluid that spins the turbine. It is the second fastest growing power industry. Source

May 19, 2007
Magnetic flux is a measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field. The SI unit of magnetic flux is the weber, and the unit of magnetic flux density is the weber per square meter, or tesla. Source

May 18, 2007
Composite materials are engineered materials made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct within the finished structure. The matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the matrix properties. Due to the wide variety of matrix and reinforcement materials available, the design potentials are incredible. Many common materials fall into the catagory of composites. Source

May 17, 2007
Light rail transit is a form of tram system that generally uses electric rail cars on private rights-of-way or sometimes in streets. Light rail traces its pedigree to horse-drawn street railways, as opposed to rapid transit technology that evolved from steam-powered commuter operations. The term light rail was devised in 1972 to describe a rail system "intended for light loads and fast movement", rather than referring to physical weight. The investment in infrastructure is also usually lighter than would be found for a heavy rail system. Source

May 16, 2007
Alexander Graham Bell was a scientist, inventor, and innovator born in Edinburgh, Scotland  in 1847. Besides his fame relating to the telephone, Bell is also notable for having worked with early home air conditioning using blocks of ice, experimenting with composting toilets and devices to capture water from the atmosphere. He also anticipated modern concerns with fuel shortages and industrial pollution. In a magazine interview published shortly before his death, he reflected on the possibility of using solar panels to heat houses. Source

May 15, 2007
A Grid-tied electrical system is a semi autonomous electrical generation system which links to the mains to feed excess generation capacity back to the local mains electrical grid. When insufficient electricity can not be generated the reverse process, drawing electricity from the mains grid can make up the short fall. Grid-tied electrical systems are common in residential and commercial solar-electric systems. Source

May 14, 2007
A relay is an electrical switch that opens and closes under the control of another electrical circuit. The switch is operated by an electromagnet to open or close one or many sets of contacts. A relay is able to control an output circuit of higher power than the input circuit. Source

May 13, 2007
Solar thermal energy is a technology for harnessing solar power for practical applications from solar heating to electrical power generation. Solar thermal collectors, such as solar hot water panels, are commonly used to generate solar hot water for domestic and light industrial applications. Solar thermal energy is used in architecture and building design to control heating and ventilation in both active solar and passive solar designs. Source

May 12, 2007
A positive displacement pump is a device used to move a liquid by trapping a fixed amount of fluid and then forcing (displacing) that trapped volume into the discharge pipe. Positive displacement pumps can be further classified as either rotary-type (for example the rotary vane pump) or reciprocating-type (for example the diaphragm pump). The same basic design can also be used to pump gases, but is usually called a compressor in this application. Source

May 11, 2007
The Autolite Lead Wedge was a battery electric vehicle, built from scratch to break a speed record in the late 1960s. Powered by 240 volts of lead acid batteries and a GE motor, the Lead Wedge reached 138 mph. Source

May 10, 2007
Aerodynamics is a branch of fluid dynamics concerned with the study of forces generated on a body in a flow of air, liquid or gas. The solution of an aerodynamic problem normally involves calculating for various properties of the flow, such as velocity, pressure, density, and temperature, as a function of space and time. This mathematical analysis and empirical approximation form the scientific basis for heavier-than-air flight. It is also a significant factor in any type of vehicle design, including automobiles, where the aerodynamics of the vehicle have a large effect on fuel consumption. Source

May 9, 2007
A Hybrid Locomotive is a locomotive that uses an on-board rechargeable energy storage system and a fueled power source for propulsion. Hybrid trains typically are powered either by fuel cell technology or the more conventional diesel-electric hybrid which reduces fuel consumption through regenerative braking and switching off the hydrocarbon engine when idling or stationary, similar to hybrid automobiles such as the Toyota Prius. Source

May 8, 2007
A Neighborhood Electric Vehicle (NEV) is a speed limited battery electric vehicle (usually 25 miles per hour in the U.S.A.) restricted by law to operation on roads with speed limits not exceeding 35 MPH. These speed restrictions are required because of a lack of federally mandated safety equipment and features which NEV's can not accommodate because of their design. To satisfy requirements for operation on streets, NEVs are equipped with three-point seat belts, windshields and windshield wipers, running lights, headlights, brake lights, reflectors, rear view mirrors, and turn signals. Source

May 7, 2007
The Brayton cycle is a constant-pressure thermodynamic cycle named after George Brayton (1830–1892), the American engineer who developed it. In 1872, Brayton filed a patent for his "Ready Motor" which, unlike the Otto or Diesel cycles, used a separate compressor and expansion cylinder. Today the Brayton cycle is generally associated with gas turbines, such as those used in airplanes and some types of generators. Source

May 6, 2007
A turbocharger is an exhaust-gas driven forced induction device used in internal combustion engines to improve engine performance by forcing compressed air into the combustion chambers, allowing more fuel to be burned, resulting in a larger power output. Source

May 5, 2007
A car club is a group of people who share a common interest in motor vehicles. Car clubs can vary widely in focus from one to another to suit the owners or enthusiasts, and many are oriented around a specific type, make, or model. Typically car clubs have been non-profit groups. Many enthusiasts are attracted to join car clubs because of the publications offered with memberships; these contain photographs, messages from other members, service and parts advice, items and vehicles wanted and/or for sale, and historical material of interest to the membership. Car clubs often host gatherings which often also welcome interested non-members and their vehicles. Source

May 4, 2007
A solar car is an electric vehicle powered by solar energy obtained from solar panels on the surface of the car. Solar cars are not practical day-to-day transportation devices at present, but are primarily demonstration vehicles and engineering exercises. Solar cars compete in races (often called rayces). Solar cars combine technology typically used in the aerospace, bicycle, alternative energy and automotive industries. Unlike typical race cars, solar cars are limited by the energy collected from solar radiation and as a result optimizing the design to account for aerodynamic drag, vehicle weight, rolling resistance and electrical efficiency are paramount. Source

May 3, 2007
Carbon credits are a tradable permit scheme that gives greenhouse gas emissions a monetary value. A credit gives the owner the right to emit one tonne of carbon dioxide. International treaties such as the Kyoto Protocol set quotas on the amount of greenhouse gases countries can produce. Businesses that are over their quotas must buy carbon credits for their excess emissions, while businesses that are below their quotas can sell their remaining credits. Credits can be exchanged between businesses or bought and sold in international markets at the prevailing market price. Source

May 2, 2007
A wind farm is a collection of wind turbines generating wind-powered electricity. Due to the variable nature of wind, production levels change dramatically with the weather. In areas with favorable wind tendancies, large scale production of wind-power can be achieved by a wind farm. Source

May 1, 2007
The history of the Electric Car includes such early examples as the Baker Electric, dating back nearly a century. Other unusual examples of early automobile techology include the Owen Magnetic and the Woods Dual Power car - both examples of hybrid gas-electric vehicles. An interesting article about some still functioning examples of these vehicles can be found here.

April 30, 2007
The first known electric locomotive was built by Robert Davidson of Aberdeen in 1837 and was powered by galvanic cells. The first mainline electrification was on the Baltimore and Ohio Railroad (B&O) in 1895. Parallel tracks on the Pennsylvania Railroad had shown that coal smoke from steam locomotives would be a major operating issue, as well as a public nuisance. A collision in the Park Avenue tunnel in 1902 led the New York State legislature to outlaw the use of smoke-generating locomotives south of the Harlem River. In response, electric locomotives began operation in 1904 on the New York Central Railroad. Source

April 28, 2007
A trolleybus is an electric bus powered by two overhead wires, from which it draws electricity using two trolley poles. The earliest tolleybus dates back to 1882, when Dr. Ernst Werner von Siemens ran his "Elektromote" in a Berlin suburb. Since then the electric trolley has become a common form of public transit in many urban areas. Source

April 27, 2007
Botts' dots are a raised pavement marker used to mark lanes on highways and roads. Botts' dots are named after Dr. Elbert Dysart Botts, a California Department of Transportation (Caltrans) engineer credited with overseeing the research that led to the development of the markers and the epoxy used to attach them to the road. Botts' dots are typically round markers, most commonly white but also often yellow, and rarely found in black or other colors. They are made of ceramic, polyester, or plastics. Botts' dots may also incorporate a reflective lens. Source

April 25, 2007
Smog is a kind of air pollution. Smog can form in almost any climate where industries or cities release large amounts of air pollution. However, it is worse during periods of warmer, sunnier weather when the upper air is warm enough to inhibit vertical circulation. It is especially prevalent in geologic basins encircled by hills or mountains. It often stays for an extended period of time over densely populated cities or urban areas. Source

April 24, 2007
Many vegetable oils may substitute for #2 Diesel fuel, most significantly as engine fuel or home heating oil. In these applications, vegetable oil used as fuel is often referred to as waste vegetable oil (WVO) if it is oil that was discarded from a restaurant or straight vegetable oil (SVO) to distinguish it from Biodiesel. Vegetable oils have similar fuel properties to diesel fuel, except for higher viscosity and lower oxidative stability. Source

April 23, 2007
A rack and pinion is a pair of gears which convert rotational motion into linear motion. Rotational motion applied to the pinion causes the rack to move side to side. The rack and pinion arrangement is commonly found in the steering mechanism of cars or other wheeled, steered vehicles. This arrangement provides a lesser mechanical advantage than other mechanisms such as recirculating ball, but much less backlash and greater feedback, or steering "feel". Source

April 22, 2007
Dynamic braking is the use of the electric traction motors as generators to slow a vehicle. This type of braking is most commonly used in railroad vehicles. Radiators in the form of large fan cooled resistor banks, called “brake grids”, dissipate the generated electric current as heat. Unlike regenerative braking, dynamic braking does not recover any of the energy lost in the braking process, it simply provides a non-mechanical suppliment to friction brakes. Source

April 21, 2007
Commuting is the process of travelling between a place of residence and a place of work. Commuting is largely a phenomenon which exists in industrialised societies, where access to modern modes of travel such as automobile, trains, buses and bicycles has enabled people to live far from their workplace. Commuting has allowed cities to expand to sizes which were previously not practical, and it has led to the proliferation of the suburbs. Source

April 20, 2007
Wind power is the conversion of wind energy into more useful forms. Most modern wind power is generated in the form of electricity by converting the rotation of turbine blades into electrical current by means of an electrical generator. In windmills, wind energy is used to turn mechanical machinery to do physical work, like crushing grain or pumping water. Source

April 19, 2007
Carbon monoxide is a colorless, odorless, and tasteless gas. It is the product of the incomplete combustion of carbon-containing compounds, notably in internal-combustion engines. It has significant fuel value, burning in air with a characteristic blue flame, producing carbon dioxide. Carbon monoxide is a significantly toxic gas with poisoning being one of the most common types of fatal poisoning. Source

April 18, 2007
Twist-locking connectors, often referred to as "Twist-Lock", are NEMA electrical devices used for connecting electrical equipment to AC mains. Unlike non-locking connectors, such as found on most small home appliances, twist-locking connectors use curved blades that once pushed into the receptacle, rotate and latch into place. The locking coupling makes for a very reliable connection. Twist-locking connectors are often used for electric vehicle charger connections. Source

April 17, 2007
Conductors are materials that readily conduct electric current. These materials are classified according to their electrical resistance, which describes how readily they allow electric current to pass when a voltage is applied. Copper is the most common material for electrical wiring, and gold for high-quality surface-to-surface contacts. However, there are also many non-metallic conductors, including graphite, solutions of salts, and all plasmas. Source

April 16, 2007
A hybrid vehicle is a vehicle that uses two or more distinct power sources. The term most commonly refers to a petroleum electric hybrid vehicle, which uses an internal combustion engine and electric batteries to power electric motors. Other kinds of hybrids vehicles include human powered bicycles with battery assist, sail boats with electric power, among many other variations. Source

April 15, 2007
A Direct drive mechanism is one that takes the power coming from a motor without any reductions, such as a gearbox. In electric vehicle terms this usually refers to a drive system that has no transmission, or single speed gear reduction, rather than multiple gear ratios. In some cases the motor, or motors, are directly coupled to the drive shaft or axle shafts. Source

April 14, 2007
Wärtsilä is a Finnish manufacturer of large diesel engines. The Wärtsilä RTA96-C turbocharged two-stroke diesel engine, currently considered the largest reciprocating engine in the world, is designed for large container ships, running on cheap, heavy fuel oil. The efficiency of the RTA96 is approximately 51.7%, the best among piston engines, and comparable to similarly sized turbine engines. The upgrades planned for the PG&E Humboldt Bay power plant includes several Wärtsilä engines capable of running on multiple types of fuel, including bio-fuels. Source

April 13, 2007
A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. Common applications that use bearings are automobile suspension systems, motors, engines, gearboxes and many others devices. Source

April 12, 2007
Hydraulic machines and tools are those which use fluid power to do work. In this type of machine, high pressure hydraulic fluid is transmitted throughout the machine to various hydraulic motors and hydraulic cylinders. The fluid is controlled directly or automatically by control valves and distributed through hoses and tubes. Hydraulics are uses in many applications ranging from very simple, such as in many automotive brake systems, to very complex machines used for construction or other industries. Source

April 11, 2007
Copper is a ductile metal with excellent electrical conductivity, and finds extensive use as an electrical conductor, thermal conductor, as a building material, and as a component of various alloys. Copper is used in a wide variety of applications including wire, circuit boards, plumbing, and many other electrical and non-electrical applications. Source

April 10, 2007
The Hotchkiss drive is a shaft-drive system of power transmission. It was the dominant form of power transmission for front-engine, rear-drive cars in the 20th century. Source

April 9, 2007
In electrical engineering, an armature is one of the two principal electrical components of an electro-mechanical machine--a motor or generator. The other is the field winding or field magnets. The armature must carry current or EMF (usually both), so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion. Source

April 8, 2007
The Automotive X Prize is a competition to inspire a new generation of efficient consumer automobiles, with the intention of reducing dependence on oil for gasoline and reducing global warming. While the rules are still being developed, international competitors will likely need to prove commercial viablity, demonstrate a minimum of 100 MPGE (miles per gallon of energy equivalent to a gallon of gas, whatever the fuel type), and meet strict emissions criteria. Source

April 7, 2007
Aviation Grade Ethanol (AGE-85) is a fuel containing approximately 85% ethanol, along with light hydrocarbons and biodiesel fuel. AGE-85 is being developed as an alternative fuel for piston engine aircraft. AGE-85 is said to burn cleaner and be more environmentally friendly than traditional aviation fuels. Source

April 6, 2007
Tetra-ethyl lead, abbreviated TEL, is an organometallic compound once commonly used as an additive in gasoline. TEL usage was largely discontinued because of the toxicity of lead. It is still used as an additive in the aviation fuel known as avgas. Source

April 4, 2007
An alternator is an electromechanical device that converts mechanical energy to alternating current electrical energy. In principle, any AC generator can be called an alternator, but usually the word refers to small rotating machines driven by automotive and other internal combustion engines. Source

April 3, 2007
A Tesla coil is a type of transformer, named after its inventor, Nikola Tesla. Tesla coils consist of a high voltage power supply, one or more high voltage capacitors and a spark gap to excite the primary side. The primary and secondary circuits are tuned so that they resonated at the same operating frequency, typically between 25 kHz and 2 MHz. Since Tesla coils often create long electrical discharges, they are quite popular devices among high-voltage enthusiasts. Source

April 2, 2007
The Grumman Kurbwatt was a battery electric vehicle built for use by the United States Postal Service in the early 1980s. Using conventional electric vehicle technology, including lead-acid batteries, the Kurbwatt easily met all the requirements for mail delivery, however only a few hundred were built. Many of the Kurbwatt vehicles are still operational today, including the highly modified racing postal van: "Gone Postal". Source

April 1, 2007
Hypermilers are drivers who exceed EPA estimated mileage on their vehicles by modifying their driving habits. Hypermilers originated from hybrid driving clubs. As people began comparing mileage they noticed that certain driving techniques could greatly improve their mileage. There are many techniques that hypermilers use to optimize their miles per gallon. Source

March 31, 2007
Global warming is the observed increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation. An increase in global temperatures can in turn cause other changes, including a rising sea level and changes in the amount and pattern of precipitation. Scientific uncertainties regarding global warming include the exact degree of climate change expected in the future, and especially how changes will vary from region to region across the globe. Source

March 30, 2007
Methane is the principal component of natural gas. Methane's relative abundance and clean burning process makes it a very attractive fuel. Methane is also a relatively potent greenhouse gas with a global warming potential 23 times greater than carbon dioxide. Source

March 29, 2007
Aluminum is a silvery and ductile metal remarkable for its ability to resist corrosion and its light weight. It is widely used in the aerospace and transportation industries. Despite its abundance, aluminum requires a great deal of energy to refine from its naturally occuring form; it is much easier to recycle aluminum such as is found in many beverage cans. Source

March 28, 2007
A multimeter is an electronic measuring instrument that combines several functions in one unit. The most basic instruments include an ammeter, voltmeter, and ohmmeter. Analog multimeters are sometimes referred to as "volt-ohm-meters", abbreviated VOM. Digital multimeters are usually referred to as "digital-multi-meters", abbreviated DMM. Source

March 27, 2007
An oscilloscope is a piece of electronic test equipment that allows signal voltages to be viewed, usually as a two-dimensional graph of one or more electrical potential differences (vertical axis) plotted as a function of time or of some other voltage (horizontal axis). Source

March 26, 2007
A machine tool is a powered mechanical device, typically used to fabricate metal components by the selective removal of metal. Machine tools can be operated manually, or under automatic control. Machine tools with computer control are known as Computer Numerical Control or more commonly CNC machines. CNC machines can precisely repeat sequences over and over for mass producing precision parts. Source

March 25, 2007
Cutting speed is the speed difference between the cutting tool and the surface of the workpiece it is operating on. Cutting speeds are a critical part of productive and economical machining in the field of manufacturing. They are equally important for the safe operation of any applicable machinery, especially in metalworking and woodworking usage. Source

March 24, 2007
The Piaggio MP3 is a tilting three-wheeled scooter. Its three-wheel mechanism can be brought to a stop and parked like a car, without a kickstand. The front suspension/steering consists of two regular Vespa style suspensions, linked by an alloy parallellogram and a central steering arm. Source

March 23, 2007
Bioenergy Conversion Factors are the numerical units and values used for comparing the energy content of various fuel sources. A useful reference for these factors can be found here.

March 22, 2007
The gas-absorption refrigerator is a refrigerator that utilizes a heat source to provide the energy needed to drive the cooling system rather than being dependent on electricity to run a compressor. These refrigerators are popular where electricity is unreliable, costly, or unavailable, or where surplus heat is available, e.g., from turbine exhausts or industrial processes. Source

March 21, 2007
Radiant heating is a heating system where heat energy is emitted from a warm element (floor, wall, overhead panel) and warms people and other objects in rooms rather than directly heating the air. The technology has existed since the Roman times. The internal air temperature for radiant heated buildings may be lower than for a conventionally heated building to achieve the same level of body comfort (the perceived temperature is actually the same), therefore radiant heating is often more efficient than conventional systems. Source

March 20, 2007
High-density polyethylene (HDPE) is a polyethylene thermoplastic made from petroleum. It takes 1.75 kilograms of petroleum (in terms of energy and raw materials) to make one kilogram of HDPE. HDPE has stronger intermolecular forces and tensile strength than lower density polyethylene. HDPE is used for such common items as milk cartons, plastic bags and even fuel tanks. It is also very easy to recycle HDPE. Source

March 19, 2007
The Time of Use meter is an electric utility meter commonly used for grid-tied residential photovoltaic systems. Depending on various factors, the Time of Use meter can have a significant advantage over the older, more common residential meters, which only measure Kilowatt-Hours. The Time of Use meter is a digital meter that is programmed to measure Kilowatt-Hours and the period of usage during which the power is used. Source

March 18, 2007
A Halbach Array is an arrangement of magnets that forms a strong magnetic field on one side of the array, but very little magnetism on the other side. This is achieved by orienting the magnets so they cancel out each other's flux in one direction, but amplify it in the opposite direction. This technology has applications in things ranging from refrigerator magnets to maglev trains. Learn more about Halbach arrays here.

March 17, 2007
Wire gauge is a measurement of how large a wire is, either in diameter or cross sectional area. This determines the amount of electrical current a wire can safely carry, as well as its electrical resistance and weight per unit of length. Wire gauge is therefore applicable to both electrical and non-electrical wires, thus it is important to electrical wiring and to structural cable. Source

March 16, 2007
The Surplus Center is a business specializing in the sale of surplus mechanical and electrical equipment. They usually have a large selection of electric motors and other parts of potential use to the Electric Vehicle community.

March 15, 2007
Automatic battery filling systems, also know as single point watering systems, are composed of devices that are attached to each battery cell and inteconnected with hoses. A mechanism inside the device automatically opens to allow water into the battery as needed. The interconnected hoses allow water to reach every cell from a single centralized point, where a water resevoir can be located and topped off when necessary. One example of a automatic battery watering system can be found here.

March 14, 2007
In electronics, a Schmitt trigger is a comparator circuit that incorporates positive feedback. When the input is higher than a certain chosen threshold, the output is high; when the input is below another (lower) chosen threshold, the output is low; when the input is between the two, the output retains its value. This dual threshold action is called hysteresis, and implies that the Schmitt trigger has some memory. The benefit of a Schmitt trigger over a circuit with only a single input threshold is greater stability (noise immunity). Source

March 13, 2007
Carsharing is a system where a fleet of cars is jointly-owned by the users. The users are organized as a democratically-controlled company, public agency, cooperative or ad hoc grouping. The fleet is made available for use by members of the carshare group in a wide variety of ways. The costs and troubles of vehicle purchase, ownership and maintenance are transferred to a central organizer. Today there are more than six hundred cities in the world where people can carshare. Source



March 12, 2007
The Dymaxion car was a three-wheeled, rear-steering vehicle designed by Buckminster Fuller in 1933. The Dymaxion had a highly aerodynamic aluminum body and was very light weight, much like an airplane. Due to these qualities, the Dymaxion was able to go between 30 and 50 miles per gallon of gasoline, using a conventional gasoline engine of the time. Only three Dymaxion cars were ever built. Source

March 11, 2007
The electric Bedford CF van, also known as a Griffon van, is a battery electric vehicle that was produced by Bedford motors and Lucas/Chloride in England for a short time in the 80's. It has a 40Kw motor running at 216 volts and a range of approximately 50 miles. There are several Griffon vans in Humboldt county, many of which are in driveable condition. Source

March 10, 2007
An operational amplifier, usually referred to as an 'op-amp', is a DC-coupled high-gain electronic voltage amplifier with differential inputs and, usually, a single output. In its ordinary usage, the output of the op-amp is controlled by negative feedback which, because of the amplifier's high gain, almost completely determines the output voltage for any given input. Op-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices. Source

March 9, 2007
A transformer is an electromagnetic induction device that transfers electricity from one electric circuit to another. Often a transformer is also used to change the voltage of the incoming electrical current, either lower or higher. Transformers, by their nature, only work with alternating current; if direct current is applied to a transformer, it will behave like a dead short - typically an undesirable condition. Most transformers also have the added benefit of electrically isolating the primary and secondary circuits, which provides extra safety for anyone handling the equipment connected to the secondary. Source

March 8, 2007
The Alisport Silent Club is an electric powered self-launching sailplane and first production electric-powered aircraft. The 13kW DC motor powers the aircraft in less than five minutes to an altitude of 2000 - 2300 feet, almost silently. Source

March 7, 2007
The Volkswagen 1-litre car is a concept car that achieves 235 miles per gallon. The high efficiency is achieved by using lightweight materials, excellent aerodynamics, and a 8.5 horsepower diesel engine. The vehicle also incorporates advanced safety features, comparable to a production car. The same techniques used improve efficiency in the 1-litre car are also applicable to other vehicles, especially hybrid and fully electric cars. Source

March 6, 2007
A diode is an electrical  component that restricts the direction of movement of charge carriers. Essentially, it allows an electric current to flow in one direction, but blocks it in the opposite direction. Thus, the diode can be thought of as an electronic version of a check valve. There are several different kinds of diodes, including Schottky, Zener, and light emitting diodes. Each kind has unique characteristics that make it desirable for certain applications. It is probably not exaggerating to say that almost every electrical device has at least one diode in it. Source

March 5, 2007
Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms. It is often referred to by its formula CO2. It is present in the Earth's atmosphere at a low concentration of approximately 0.03%-0.06%. Despite its small concentration, CO2 is a very important component of Earth's atmosphere, because it absorbs infrared radiation and enhances the greenhouse effect. Some other greenhouse gases, many of which are even more potent than CO2, are methane, nitrous oxide, ozone and even water vapor. Source

March 4, 2007
The Corbin Sparrow is a single-passenger, three wheeler, battery electric vehicle designed specifically for commuting and city driving. It was produced by Corbin Motors. Powered by a 20 kW (continuous) 156-volt DC or 3-phase AC motor, the Sparrow has a range of 20 to 40 miles and a top speed of 70 mph. Energy is supplied by thirteen 12-volt deep-cycle lead-acid batteries. Corbin motors filed for bankruptcy in 2003, however Myers Motors has restarted production of the Sparrow using a new name: MM NmG (No more Gas). Source

March 3, 2007
The EV Tradin' Post is the self proclaimed "best place to buy an electric car" on the internet. This free service lists advertisements for electric vehicles, parts and accessories, both for sale and wanted. Visit the Tradin' Post here.

March 2, 2007
The Chevrolet Electric S-10, introduced in 1997 was an OEM modified variant of Chevrolet's S-10 pickup truck which ran solely upon electricity, and was marketed primarily to utility fleet customers. The majority of power electronics were carried over directly from the EV1. Unlike the EV1, some of the S-10 vehicles were eventually sold to private parties, and remain in use. Unfortunately, many were also destroyed, like the EV1. For more infomation, visit EV Bones a company specializing in the repair and restoration of the Electric S-10. Source

March 1, 2007
The Electric Vehicle Discussion Mailing List, founded in 1991, is an email-based forum, used to exchange ideas, information, and experiences relating to electric vehicles. Discussion threads often including advice on design, fabrication, and trouble shooting of EVs, new vehicles under development, changes in state and federal policies that effect EVs, and much more. Members of the list include a wide assortment of folks from around the world, many with extensive backgrounds in electronics, motors, and batteries, but the list also includes beginners and hobbyists as well. Everyone is welcome, and everyone has something to contribute. Source

February 28, 2007
A regenerative brake is a device or system which allows a vehicle to recapture part of the kinetic energy that would otherwise be lost to heat when braking and make use of that power either by storing it for future use or feeding it back into a power system for other functions to use. Many electric and electric-hybrid vehicles utilize regenerative braking to improve their range and efficiency. Source

February 27, 2007
A switched-mode power supply is an electronic power supply unit that incorporates a switching regulator — an internal control circuit that switches power transistors (such as MOSFETs) rapidly on and off in order to stabilize the output voltage or current. Switching regulators are used as replacements for the linear regulators when higher efficiency, smaller size or lighter weight are required. Switched-mode circuit topology is used dc-dc convertors, motor controllers and many other common applications. Source

February 26, 2007
A fluorescent lamp is a gas-discharge lamp that uses electricity to excite mercury vapor in argon or neon gas, resulting in a plasma that produces short-wave ultraviolet light. This light then causes a phosphor to fluoresce, producing visible light. Fluorescent lamps are more efficient than incandescent light bulbs of an equivalent brightness. This is because more of the consumed energy is converted to usable light and less is converted to heat, allowing fluorescent lamps to run cooler. Source

February 25, 2007
Copper indium gallium selenide (CIGS) is a new semiconductor material used for high-efficiency photovoltaic cells, in the form of polycrystalline thin films. Unlike the silicon cells based on p-n junction, the structure of CIGS is a complex heterojunction system. Thin film PV cells are used in the "shingle" style panels and have many other potential uses. Source

February 24, 2007
Straw-bale construction is a building method that uses straw bales as structural elements, insulation, or both. It has advantages over some conventional building system because of its cost and easy availability, and its high insulation value. Visit the CCAT website for more information. Source

February 23, 2007
Biodiesel is the common name for methyl esters made from waste vegetable oils (WVO). The WVO is put through a process called transesterification which breaks down the viscosity and increases the flammability of the oil. The result is a fuel that can be used in any diesel engine without engine modifications. Source

February 22, 2007
A fuel cell is an electrochemical engine that converts the chemical energy of a fuel directly to electricity. Almost always the fuel is hydrogen or a hydrogen rich gas mixture. A fuel cell is similar to a battery in that both devices convert chemical energy directly to electricity. A fuel cell operates at an efficiency of 40-50%. Source

February 21, 2007
Richard Trevithick (April 13, 1771 – April 22, 1833) was a British inventor, engineer and builder of the first working railway steam locomotive. Trevithick built a full-size steam road carriage in 1801. He named the carriage 'Puffing Devil' and, on Christmas Eve that year, he demonstrated it by successfully carrying several men up Camborne Hill and then continuing on to the nearby village of Beacon. This event is believed by many to be the first demonstration of transportation by (steam) auto-motive power. Source

February 20, 2007
The Stirling engine is a closed-cycle piston heat engine. The Stirling engine is traditionally classified as an external combustion engine, like a steam engine, operating through the use of an external heat source and heat sink, each maintained within a limited temperature range, and having sufficient temperature difference between them. In the conversion of heat into mechanical work, Stirling engines can achieve the highest efficiency of any real heat engine, up to 80% of the Carnot efficiency. Source

February 19, 2007
Nikola Tesla (10 July 1856 - 7 January 1943) was a world-renowned inventor, physicist, mechanical engineer and electrical engineer. He is best known for his revolutionary work in, and numerous contributions to, the discipline of electricity and magnetism in the late 19th and early 20th century. Tesla's patents and theoretical work formed the basis of modern alternating current electric power (AC) systems, including the polyphase power distribution systems and the AC motor, with which he helped usher in the Second Industrial Revolution. Source

February 18, 2007
James Watt (19 January 1736 – 19 August 1819) was a Scottish inventor and engineer whose improvements to the steam engine were fundamental to the changes wrought by the Industrial Revolution. Although the steam engine already existed, it was impractical and ineffective. Watt redesigned the engine to cause the steam to condense in a separate chamber apart from the piston, and to maintain the temperature of the cylinder at the same temperature as the injected steam. The efficiency of the steam engine was increased dramatically. Source

February 17, 2007
The multiple expansion steam engine is an external combustion heat engine that makes use of the heat energy that exists in steam, converting it to mechanical work. Such engines use either three or four expansion stages and are known as triple and quadruple expansion engines respectively. These engines use a series of double-acting cylinders of progressively increasing diameter and/or stroke and hence volume. These cylinders are designed to divide the work into three or four, as appropriate, equal portions for each expansion stage. Multiple cylinders split the expansion into more stages to increase efficiency. Source

February 16, 2007
Foil bearings are a type of air bearing. A shaft is supported by a compliant, spring loaded foil journal lining. Once the shaft is spinning fast enough, the working fluid (usually air), pushes the foil away from the shaft so that there is then no contact. The shaft and foil are separated by the air's high pressure which is generated by the rotation which pulls gas into the bearing via viscosity effects. A high speed of the shaft with respect to the foil is required to initiate the air gap, and once this has been achieved, no wear occurs. Foil bearings are used in the Capstone Microturbines used in some hybrid electric vehicles. Source

February 15, 2007
Propane is a three-carbon alkane, normally a gas, but compressible to a liquid that is transportable. It is derived from other petroleum products during oil or natural gas processing. It is commonly used as a heat source for engines, barbecues, and homes. Propane is also instrumental in providing off-the-grid refrigeration. In highly purified form, propane (R-290) can serve as an environmentally friendly refrigerant in mechanical refrigeration systems designed to use R-12, R-22 or R-134a chloro- or fluorocarbon based refrigerants. Source

February 14, 2007
Insolation is solar radiation received at the earth's surface (source), which can be collected for various purposes including generating electricity or heating water. Photovoltaic (PV) systems capture the sun's energy and generate electricity that can be stored in batteries or, using an inverter, fed into the utility power grid. By using an electric vehicle with such a system, the fuel savings can offset the fairly high expense of installing a PV system in only a few years, while using PV for only household needs usually takes much longer.

February 13, 2007
A microcontroller (or MCU) is a computer-on-a-chip. It is a type of microprocessor emphasizing self-sufficiency and cost-effectiveness, in contrast to a general-purpose microprocessor (the kind used in a PC). A typical microcontroller contains all the memory and interfaces needed for a simple application, whereas a general purpose microprocessor requires additional chips to provide these functions. This type of microcontroller is commonly found in electronic devices to control complex functions. Many electric vehicle components contain microcontrollers for functions such as charging, motor control and battery monitoring. Source

February 12, 2007
Power semiconductor devices are used as switches or rectifiers in electronic circuits (switch mode power supplies for example).  Some common power devices are the power diode, thyristor, power MOSFET and IGBT (insulated gate bipolar transistor). Various combinations of these components are used in electric vehicle motor controllers, some of which have advantages in certain applications. Source

February 11, 2007
The ignitron is mercury vapor rectifier in which an arc is switched between a (usually graphite) anode and a mercury pool cathode. The discharge is initiated by an ignitor electrode which dips into the mercury pool cathode. On application of a suitable impulse current/voltage to this ignitor an electron emitting source is formed at the point at which the ignitor contacts the pool. This initiates the arcing between the anode and cathode. Ignitrons are suited to applications where power control of high voltages or currents is required. Welding is probably the most common application. Ignitrons are very limited with regards their physical orientation. This reason being that they rely upon a pool of liquid at one end of the device that must be correctly positioned for the ignitor to function correctly. Due to this physical limitation the ignitron is not of any practical use for electric vehicles. Source

February 10, 2007
The National Electric Drag Racing Association, NEDRA, is a coalition of drag racing fans, electric drag racing vehicle owners and drivers, individuals interested in promoting the sport of EV drag racing, EV parts suppliers, EV manufacturers and other environmentally concerned companies and individuals. NEDRA exists to increase public awareness of electric vehicle (EV) performance and to encourage through competition, advances in electric vehicle technology. NEDRA achieves this by organizing and sanctioning safe, silent and exciting electric vehicle drag racing events. Source

February 9, 2007
Battery Regulators are devices added to a large battery pack to help keep the individual batteries at the same state of charge. The simplest type of regulator is the shunt regulator that allows charging current to bypass the battery when the voltage reaches a certain level. Using shunt regulators allows the charging process to continue without overcharging the batteries that have already reached a full charge. More sophisticated types of regulators can actually charge or discharge individual batteries to keep the state of charge consistant within the larger battery pack during both charging and discharging operations. One of the most versatile battery regulators in the "Battery Balancer" designed by Lee Hart. The Battery Balancer is not commercially available, but plans for constructing one can be found here.


February 8, 2007
Peukert's Law, presented by the German scientist W. Peukert in 1897, expresses the capacity of a battery in terms of the rate at which it is discharged. As the rate increases, the battery's capacity decreases, although its actual capacity tends to remain fairly constant. The Peukert law becomes a key issue in a battery electric vehicle where batteries rated at 20 hour discharges are used at much greater rates of about 1 hour. An excellent comparison of the Peukert effect to beer can be found here. Source

February 7, 2007

February 6, 2007
The nickel-iron battery, also known as the Edison Cell, is a storage battery having a Nickel oxide-hydroxide cathode and an iron anode, with an electrolyte of potassium hydroxide. The nominal cell voltage is 1.2V. It is a very robust battery which is tolerant of abuse, (overcharge, overdischarge, short-circuiting and thermal shock) and can have very long life even if so treated.  It is notable for being used in some electric vehicles made in the early twentieth century, with great success. Unfortunately it is not generally used anymore due to a fairly low energy density and high maintenance requirements. An interesting article about a Baker Electric car with Edison Cells can be found here. Source

February 5, 2007
Stanford R. Ovshinsky (1923- ) is a self-taught Jewish American-Lithuanian engineer, inventor, and physicist. He has invented amorphous semiconductor materials, which gave rise to a whole new segment of material engineering, aiding in the construction of semiconductors, solar energy, and electric cars. These materials are used in photocopy machines, fax machines and LCD displays. Ovshinsky was granted numerous patents in the 1970s and '80s for amorphous semiconductor materials. He has more recently been involved in the development of Nickel Metal-Hydride batteries for electric vehicles. Source

February 4, 2007
The first test drive is usually conducted on a converted electric vehicle to determine its roadworthiness. Often, some crucial parts of the vehicle may still be uninstalled at this point, but the owner/convertor is excited to have a functioning vehicle and will take it for a drive "around the block". Due to the untested condition of the vehicle it is also not unusual for something to go wrong in the course of the test drive, but these problems are usually minor enough not to stifle the excitement of the owner, and then repairs and modifications can be made to solve the problems.

February 3, 2007
A homopolar motor or generator is an electromagnetic device that converts mechanical energy into or out of electricity, similarly to other kinds of electric motors. The most distinctive feature of the homopolar motor is that the armature is arranged so the polarity of the magnetic field remains the same as it rotates. The principles that allow the homopolar motor to function are not entirely understood, and so far, very few practical uses have been discovered for it.


February 2, 2007
A bridge rectifier, also known as a full wave rectifier, is a semiconductor device used in an electrical circuit to change alternating current (AC) to direct current (DC). A bridge rectifier is composed of four diodes arranged in a configuration that allows each of the two AC inputs to be connected to the anode of one diode and the cathode of another. The other end of each of the diodes is connected to the matching diode from the other AC input. A bridge rectifier by itself can often be used to charge a battery pack with an overall voltage close to the line voltage of 120 VAC. Such a setup is commonly referred to as a "Bad Boy" charger, and can be dangerous if it is not handled very carefully.

February 1, 2007
AC Induction drive is a form of electric vehicle propulsion that uses an alternating current in an induction motor. Compared to the more common DC powered systems, AC induction is much more complex and expensive. For this reason, AC drives are uncommon in "home-made" EV conversions, although some do exist. Many factory built EVs do use AC drive, some of the advantages being the ability to use regenerative braking, a simplified and lighter mechanical drive-train, no motor brushes and a slight improvement in overall efficiency.

January 31, 2007
Battery chemistry is the type of materials used in an electrical storage battery. The most common type is Flooded Lead Acid (FLA), which uses lead plates for the electrodes and sulfuric acid for the electrolyte. FLA batteries are relatively cheap, widely available and easily recycleable. Despite their relatively low capacity, the other factors in their favor make FLA batteries the most cost effective type of deep-cycle battery for use in electric vehicles. Other more advanced battery chemistries exist, but none are as affordable, available and practical as flooded lead acid.

January 30, 2007
Pulse Width Modulation (PWM) is a common method of controlling an electric motor, especially in modern electric vehicles. A PWM controller is a solid state device that uses transistors to interrupt the voltage and current to the load which is typically a series wound Direct Current motor. By switching on and off thousands of times per second, the PWM controller can control the speed and power of the motor, and retain a high degree of efficiency. To the operator of the vehicle, this results in a seamless transition from motionlessness to moving at any desired speed within the capabilities of the vehicle.

January 29, 2007
MIG welding is a common type of metal welding often used for physically fusing two pieces of metal together with a similar filler metal in between. It is usually said that MIG welding is the easiest of all types of welding to learn. In a MIG welder, a spool of wire provides the filler material and feeds through an electrode in the handle of the welder. The speed that the wire feeds out can be adjusted to suit the type of welding being performed. Small 120VAC MIG welders are often used in the construction of battery racks and boxes for Electric Vehicles, as well as other metal parts needed for conversion.

January 28, 2007
In electric vehicles rolling resistance is the measure of energy lost to the inefficiency of the tires. Most factory built EVs had some kind of "Low Rolling Resistance" (LRR) tire installed originally. Many of these LRR tires are no longer available, however there are several new tires that possess similar qualities. Rolling resistance only accounts for a small percentage of the energy used to propel a vehicle down the road, but in electric vehicles even small improvements in efficiency can increase the range considerably.


January 27, 2007
The state of charge (SOC) of a battery is often checked by measuring the voltage. This is not a very accurate way of determining battery SOC, since the voltage of many types of batteries will change considerably based on how much power is being drawn from it. A more accurate way of measuring SOC is to count the amp-hours drawn from the battery and compare that to the expected capacity.