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Topic Review
Spark Gap
A spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. When the potential difference between the conductors exceeds the breakdown voltage of the gas within the gap, a spark forms, ionizing the gas and drastically reducing its electrical resistance. An electric current then flows until the path of ionized gas is broken or the current reduces below a minimum value called the "holding current". This usually happens when the voltage drops, but in some cases occurs when the heated gas rises, stretching out and then breaking the filament of ionized gas. Usually, the action of ionizing the gas is violent and disruptive, often leading to sound (ranging from a snap for a spark plug to thunder for a lightning discharge), light and heat. Spark gaps were used historically in early electrical equipment, such as spark gap radio transmitters, electrostatic machines, and X-ray machines. Their most widespread use today is in spark plugs to ignite the fuel in internal combustion engines, but they are also used in lightning arresters and other devices to protect electrical equipment from high-voltage transients.
  • 7.3K
  • 08 Oct 2022
Topic Review
Intel 80386
The Intel 80386, also known as i386 or just 386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors and were the CPU of many workstations and high-end personal computers of the time. As the original implementation of the 32-bit extension of the 80286 architecture, the 80386 instruction set, programming model, and binary encodings are still the common denominator for all 32-bit x86 processors, which is termed the i386-architecture, x86, or IA-32, depending on context. The 32-bit 80386 can correctly execute most code intended for the earlier 16-bit processors such as 8086 and 80286 that were ubiquitous in early PCs. (Following the same tradition, modern 64-bit x86 processors are able to run most programs written for older x86 CPUs, all the way back to the original 16-bit 8086 of 1978.) Over the years, successively newer implementations of the same architecture have become several hundreds of times faster than the original 80386 (and thousands of times faster than the 8086). A 33 MHz 80386 was reportedly measured to operate at about 11.4 MIPS. The 80386 was introduced in October 1985, while manufacturing of the chips in significant quantities commenced in June 1986. Mainboards for 80386-based computer systems were cumbersome and expensive at first, but manufacturing was rationalized upon the 80386's mainstream adoption. The first personal computer to make use of the 80386 was designed and manufactured by Compaq and marked the first time a fundamental component in the IBM PC compatible de facto standard was updated by a company other than IBM. In May 2006, Intel announced that 80386 production would stop at the end of September 2007. Although it had long been obsolete as a personal computer CPU, Intel and others had continued making the chip for embedded systems. Such systems using an 80386 or one of many derivatives are common in aerospace technology and electronic musical instruments, among others. Some mobile phones also used (later fully static CMOS variants of) the 80386 processor, such as BlackBerry 950 and Nokia 9000 Communicator. Linux continued to support 80386 processors until December 11, 2012; when the kernel cut 386-specific instructions in version 3.8.
  • 7.1K
  • 23 Oct 2022
Topic Review
Anodizing
Anodizing is an electrochemical process by which the thickness of the natural oxide layer present on metals is increased. Anodizing is used to improve the corrosion and wear resistance of the substrate, to enhance the adhesion of coatings and for aesthetics reasons. The properties, chemistry and morphology of the resulting anodic oxide film depend on the anodizing parameters chosen.
  • 7.0K
  • 25 Jan 2021
Topic Review
Mercedes-Benz 9G-Tronic Transmission
9G-Tronic is Mercedes-Benz's trademark name for its nine-speed automatic transmission, starting off with the W9A 700 (Wandler-9-Gang-Automatik bis 700 Nm Eingangsdrehmoment; converter-9-gear-automatic with 516 lb-ft maximum input torque; type 725.0) as core model.
  • 6.9K
  • 30 Nov 2022
Topic Review
Toophan
The Toophan (Persian: طوفان‎ "Storm", rarely Toofan) is an Iranian SACLOS anti-tank guided missile reverse-engineered from the United States of America BGM-71 TOW missile. The Toophan 1, an unlicensed copy of the BGM-71A TOW missile, began mass production in 1988 and the Toophan 2, a BGM-71C ITOW variant, was publicly shown in 2000. The Toophan comes in at least 11 variants, many of which are poorly documented, including variants with laser guidance, thermobaric warheads, and tandem-warheads with increased penetration. The Toophan is manufactured jointly by the Aerospace Industries Organization of Iran and Iran Electronics Industries. It's normally deployed from ground-based tripods, and can also be mounted on fighting vehicles and helicopters. Like the BGM-71 TOW missile, the Toophan is a large, rugged, powerful, and reliable anti-tank guided missile deployed by small teams against tanks, armored vehicles, buildings, and other targets. The Toophan forms the backbone of the Iranian Armed Forces's ATGM inventory and is procured in large quantities in a variety of variants. The Toophan has been exported to the governments of Iraq and Syria and to a large number of non-state actors in the Middle East, and has been used in the Iran–Iraq War, the 2006 Lebanon War and the Iraqi, Syrian, and Yemeni Civil Wars.
  • 6.7K
  • 14 Nov 2022
Topic Review
Paternoster
A paternoster (/ˈpeɪtərˈnɒstər/, /ˈpɑː-/, or /ˈpæ-/) or paternoster lift is a passenger elevator which consists of a chain of open compartments (each usually designed for two persons) that move slowly in a loop up and down inside a building without stopping. Passengers can step on or off at any floor they like. The same technique is also used for filing cabinets to store large amounts of (paper) documents or for small spare parts. The much smaller belt manlift which consists of an endless belt with steps and rungs but no compartments is also sometimes called a paternoster. The name paternoster ("Our Father", the first two words of the Lord's Prayer in Latin) was originally applied to the device because the elevator is in the form of a loop and is thus similar to rosary beads used as an aid in reciting prayers. The construction of new paternosters was stopped in the mid-1970s due to safety concerns, but public sentiment has kept many of the remaining examples open. By far most remaining paternosters are in Europe, with 230 examples in Germany, and 68 in the Czech Republic. Only three have been identified outside Europe: one in Malaysia, one in Sri Lanka, and another in Peru.
  • 6.5K
  • 01 Nov 2022
Topic Review
9M133 Kornet
The 9M133 Kornet (Russian: Корнет; "Cornet", NATO reporting name AT-14 Spriggan, export designation Kornet-E) is a modern Russian man-portable anti-tank guided missile (ATGM) intended for use against main battle tanks. It was first introduced into service with the Russian army in 1998. The Kornet is among the most capable Russian ATGMs. It is not intended to fully replace previous systems, due to its high cost. The Kornet comes in variants with thermobaric warheads for use against soft targets. It was further developed into the 9M133 Kornet-EM, which has increased range, fire-and-forget capability, and an improved warhead. The Kornet has been widely exported and is produced under license in several countries. It was first used in combat in 2003 and has since been used in many conflicts. The NATO reporting name AT-14 Spriggan is derived from the spriggan, a legendary creature from Cornish faery lore.
  • 6.4K
  • 08 Nov 2022
Topic Review
Chinese Polearms
The three most common types of Chinese polearms are the ge (戈), qiang (槍), and ji (戟). They are translated into English as dagger-axe, spear, and halberd. Dagger-axes were originally a short slashing weapon with a 0.9 to 1.8 m long shaft, but around the 4th century BC a spearhead was added to the blade, and it became a halberd. The spear is also sometimes called a mao (矛), which is sometimes used to designate polearms with a wavy snake-like spearhead. There was another polearm weapon known as the pi (鈹), translated into English as either sword-staff or long lance, that was used from ancient times until the Han dynasty. It was essentially a short sword attached to a stick. From the Warring States period onward, the length of Chinese polearms varied from around 2.8 m to 5.5 m, however there is no specific designation for a pike in the traditional Chinese lexicon. A very long spear is just called a long spear.
  • 6.3K
  • 13 Oct 2022
Topic Review
Intel 80486
The Intel 80486, also known as the i486 or 486, is a higher performance follow-up to the Intel 80386 microprocessor. The 80486 was introduced in 1989 and was the first tightly pipelined x86 design as well as the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating-point unit. It represents a fourth generation of binary compatible CPUs since the original 8086 of 1978. A 50 MHz 80486 executes around 40 million instructions per second on average and is able to reach 50 MIPS peak performance. Approximately twice as fast as the 80386 or 80286 per clock cycle, thanks to its five stage pipeline with all stages bound to a single cycle. The on chip enhanced FPU unit was also significantly faster than the 80387 per cycle.
  • 6.3K
  • 03 Nov 2022
Topic Review
Armor-Piercing Ammunition
Armour-piercing ammunition (AP) is a type of projectile designed to penetrate either body armour or vehicle armour. From the 1860s to 1950s, a major application of armour-piercing projectiles was to defeat the thick armour carried on many warships and cause damage to their lightly-armoured interiors. From the 1920s onwards, armour-piercing weapons were required for anti-tank missions. AP rounds smaller than 20 mm are intended for lightly-armoured targets such as body armour, bulletproof glass and lightly-armoured vehicles. As tank armour improved during World War II, anti-vehicle rounds began to use a smaller but dense penetrating body within a larger shell, firing at very high muzzle velocity. Modern penetrators are long rods of dense material like tungsten or depleted uranium (DU) that further improves the terminal ballistics.
  • 6.3K
  • 12 Oct 2022
Topic Review
Nag (Missile)
The Nag missile (IAST: Nāga; en: Cobra), also called "Prospina" for the land-attack version, is an India n third-generation, all-weather, fire-and-forget, lock-on after launch, anti-tank guided missile (ATGM) with an operational range of 500 m to 20 km. It has a single-shot hit probability of 90% and a ten-year, maintenance-free shelf life. The Nag has five variants under development: a land version, for a mast-mounted system; the helicopter-launched Nag (HELINA) also known as Dhruvastra; a "man-portable" version (MPATGM); an air-launched version which will replace the current imaging infra-red (IIR) to millimetric-wave (mmW) active radar homing seeker; and the Nag Missile Carrier (NAMICA) "tank buster", which is a modified BMP-2 Infantry Fighting Vehicle (IFV) produced under license in India by Ordnance Factory Medak (OFMK). Development of the Nag is part of the Integrated Guided Missile Development Program (IGMDP), run by Defence Research and Development Organisation (DRDO). It is manufactured by Bharat Dynamics Limited (BDL). India's Ministry of Defence (MoD) announced on 19 July 2019 that the missile was ready for production. The Defence Research and Development Organization (DRDO) successfully completed the final trial of Nag anti-tank missile using a live warhead on a dud tank at Pokhran army ranges at 6.45 am on Oct 21, 2020.
  • 5.9K
  • 09 Oct 2022
Topic Review
AMD Radeon Rx 200 Series
The AMD Radeon R5/R7/R9 200 series is a family of GPUs developed by AMD. These GPUs are manufactured on a 28 nm Gate-Last process through TSMC or Common Platform Alliance.
  • 5.7K
  • 18 Oct 2022
Topic Review
Magellan's Circumnavigation
In 1519, the Portuguese naval officer and explorer Ferdinand Magellan led a Spanish expedition to find a western route to the East Indies and reach the Moluccas or Spice Islands (in present day Indonesia) with a fleet known as the Armada de Molucca. After the death of Magellan in the Philippines in 1521 and following several other short-lived leaderships, Spanish navigator Juan Sebastián Elcano led the expedition to the Spice Islands and ultimately across the Indian Ocean and up the Atlantic ocean back to Spain, resulting in the first circumnavigation of the world in 1522. The expedition is therefore also known as the Magellan–Elcano circumnavigation. The goal of the expedition was to find a western route to the Moluccas (Spice Islands) and trade for spices. Magellan left Spain on 20 September 1519, sailed across the Atlantic, and discovered the strait that now bears his name, allowing him to pass through the southern tip of South America into the Pacific Ocean (which he named). The fleet performed the first ever crossing of the Pacific, stopping in what is today called the Philippines , and eventually reached the Moluccas, accomplishing its goal. A much-depleted crew finally returned to Spain on 6 September 1522. The fleet initially consisted of about 270 men and five ships: four carracks and one caravel. The expedition faced numerous hardships including mutinies, starvation, scurvy, storms, and hostile encounters with indigenous people. Magellan died in battle in the Philippine islands and was succeeded as captain-general by a series of officers, with Juan Sebastián Elcano leading the trip onward to Spain. He and seventeen other men in one ship (the Victoria) were the only ones to circumnavigate the globe. The expedition was funded mostly by King Charles I of Spain, with the hope that it would discover a profitable western route to the Moluccas, as the eastern route was controlled by Portugal under the Treaty of Tordesillas. Though the expedition did find a route, it was much longer and more arduous than expected, and was therefore not commercially useful. Nevertheless, the first circumnavigation has been regarded as a great achievement in seamanship, and had a significant impact on the European understanding of the world.
  • 5.7K
  • 16 Nov 2022
Topic Review
E-learning (Theory)
E-learning theory describes the cognitive science principles of effective multimedia learning using electronic educational technology.
  • 5.6K
  • 25 Nov 2022
Topic Review
Nose Ring (Animal)
A nose ring is inserted into the nose of an animal. Nose rings are used to control bulls and occasionally cows, and to help wean young cattle by preventing suckling. Nose rings are used on pigs to discourage rooting. Some nose rings are installed through a pierced hole in the nasal septum or rim of the nose and remain there, while others are temporary tools.
  • 5.6K
  • 03 Nov 2022
Topic Review
FN Baby Browning
The 1931 Fabrique Nationale ("FN") Baby Browning Pistol is a small blowback-operated semi-automatic pistol designed by Belgium-born Dieudonné Saive chambered in .25 ACP (6,35mm). The pistol features a six-round magazine capacity and is a striker-fired, single action, blow back mechanism. The manual thumb operated safety locks the slide in the closed position when engaged using side thumb pressure.
  • 5.5K
  • 14 Oct 2022
Topic Review
Tin Can
A tin can, tin (especially in British English, Australian English and Canadian English), steel can, steel packaging or a can, is a container for the distribution or storage of goods, composed of thin metal. Many cans require opening by cutting the "end" open; others have removable covers. Cans hold diverse contents: foods, beverages, oil, chemicals, etc. Steel cans are made of tinplate (tin-coated steel) or of tin-free steel. In some dialects, even aluminium cans are called "tin cans".
  • 5.5K
  • 26 Oct 2022
Topic Review
Derringer
A derringer is a small handgun that is neither a revolver nor a semi/fully automatic pistol. It is not to be confused with mini-revolvers or pocket pistols, although some later derringers were manufactured with the pepperbox configuration. The modern derringer is often multi-barreled, and is generally the smallest usable handgun of any given caliber and barrel length due to the lack of a moving action, which takes up more space behind the barrel. It is frequently used by women because it is easily concealable in a purse or a stocking. The original Philadelphia Deringer was a muzzleloading caplock single-shot pistol introduced in 1825 by Henry Deringer. In total, approximately 15,000 Deringer pistols were manufactured. All were single barrel pistols with back-action percussion locks, typically .41 caliber with rifled bores, and walnut stocks. Barrel length varied from 1.5 to 6 in (38 to 152 mm), and the hardware was commonly a copper-nickel alloy known as "German silver". The term "derringer" (/ˈdɛrɪndʒər/) became a genericized misspelling during the reporting of the Lincoln assassination, which was committed with a concealed Philadelphia Deringer. Many copies of the original Philadelphia Deringer pistol were made by other gunmakers worldwide, and the name remained often misspelled; this misspelling soon became an alternative generic term for any pocket pistol, along with the generic phrase "palm pistol'", which Deringer's competitors invented and used in their advertising. With the advent of metallic cartridges, pistols produced in the modern form are still commonly called "derringers".
  • 5.5K
  • 01 Nov 2022
Topic Review
Luxury Vehicle
A luxury vehicle provides increased levels of comfort, equipment, amenities, quality, performance, and status relative to regular cars for an increased price. The term is subjective and reflects both the qualities of the car and the brand image of its manufacturer. Luxury brands rank above premium brands, though there is no fixed demarcation between the two. Traditionally, most luxury cars were large vehicles, though smaller sports-oriented models were always produced. “Compact“ luxury vehicles such as hatchbacks, and off-road capable sport utility vehicles, are relatively modern trends.
  • 5.5K
  • 27 Oct 2022
Biography
Jack Parsons
John Whiteside Parsons (born Marvel Whiteside Parsons;[1] October 2, 1914 – June 17, 1952) was an American rocket engineer, chemist, and Thelemite occultist. Associated with the California Institute of Technology (Caltech), Parsons was one of the principal founders of both the Jet Propulsion Laboratory (JPL) and the Aerojet Engineering Corporation. He invented the first rocket engine to use a
  • 5.5K
  • 15 Nov 2022
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