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Topic Review
Gyro-Stabilized Camera Systems
Gyro-stabilized camera systems use modern electronic position data to correct for movements of the platforms they are mounted on to enable a high degree of stabilization. The systems often use a multi-axis gyro stabilization to enable the use of zoom lenses and high definition capture, despite the high amounts of vibrations and movements in aircraft, helicopters or other vehicles. The applications range from security and military operations, law enforcement, ENG, sports broadcasting documentary, natural history, and feature film productions..
  • 3.5K
  • 14 Oct 2022
Topic Review
Militarization of Police
The militarization of police is the use of military equipment and tactics by law enforcement officers. This includes the use of armored personnel carriers (APCs), assault rifles, submachine guns, flashbang grenades, grenade launchers, sniper rifles, and SWAT (special weapons and tactics) teams. The militarization of law enforcement is also associated with intelligence agency–style information gathering aimed at the public and political activists and with a more aggressive style of law enforcement. Criminal justice professor Peter Kraska has defined militarization of police as "the process whereby civilian police increasingly draw from, and pattern themselves around, the tenets of militarism and the military model". Observers have noted the militarizing of the policing of protests. Since the 1970s, riot police have fired at protesters using guns with rubber bullets or plastic bullets. Tear gas, which was developed by the United States Army for riot control in 1919, is still widely used against protesters. The use of tear gas in warfare is prohibited by various international treaties that most states have signed; however, its law enforcement or military use for domestic or non-combat situations is permitted. Concerns about the militarization of police have been raised by both ends of the political spectrum in the United States , with both the libertarian Cato Institute and the American Civil Liberties Union (ACLU) voicing criticisms of the practice. The Fraternal Order of Police has spoken out in favor of equipping law enforcement officers with military equipment, claiming that it increases the officers' safety and enables them to protect members of the public and other first responders (e.g., firefighters and emergency medical services personnel). However, a 2017 study showed that police forces which received military equipment were more likely to have violent encounters with the public, regardless of local crime rates. A 2018 study found that militarized police units in the United States were more frequently deployed to communities with large shares of African-Americans, even after controlling for local crime rates. Many countries also have a gendarmerie, which is a military force with law enforcement duties among the civilian population. France classifies some weapons as "intermediary force weapons" such as its LBD 40 refitted version of the Swiss B&T GL06 military grenade launcher, which is used in riot police situations or against individual persons in more specific interventions. While not having the full power of military guns, some weapons are heavier than regular police weaponry and are still lethal. These are often referred to with the "limited lethality" appellation.
  • 3.5K
  • 11 Oct 2022
Topic Review
Starlink (Satellite Constellation)
Starlink is a satellite constellation being constructed by American company SpaceX to provide satellite Internet access. The constellation will consist of thousands of mass-produced small satellites, working in combination with ground transceivers. SpaceX also plans to sell some of the satellites for military, scientific or exploratory purposes. (As of January 2020), SpaceX has deployed 182 satellites. They plan to deploy 60 more per Falcon 9 launch, with launches as often as every two weeks after late 2019. In total, nearly 12,000 satellites will be deployed by the mid-2020s, with a possible later extension to 42,000. The initial 12,000 satellites are planned to orbit in three orbital shells: first placing approximately 1,600 in a 550-kilometer-altitude (340 mi) shell, then approximately 2,800 Ku- and Ka-band spectrum satellites at 1,150 km (710 mi) and approximately 7,500 V-band satellites at 340 km (210 mi). Commercial operation could begin in 2020. Concerns have been raised about the long-term danger of space junk resulting from placing thousands of satellites in orbits above 1,000 kilometres (620 mi) and a possible impact on astronomy, although SpaceX is reportedly attempting to solve the issue. The total cost of the decade-long project to design, build and deploy the constellation was estimated by SpaceX in May 2018 to be about US$10 billion. Product development began in 2015, with the first two prototype test-flight satellites launched in February 2018. A second set of test satellites and the first large deployment of a piece of the constellation occurred on 24 May 2019 (UTC) when the first 60 operational satellites were launched. The SpaceX satellite development facility in Redmond, Washington, houses the Starlink research, development, manufacturing and on-orbit control operations.
  • 3.4K
  • 11 Nov 2022
Topic Review
Carbon-Based Quantum Dots for Supercapacitors
Carbon-based Quantum dots (C-QDs) are carbon-based materials that experience the quantum confinement effect, which results in superior optoelectronic properties. In recent years, C-QDs have attracted attention significantly and have shown great application potential as a high-performance supercapacitor device. C-QDs (either as a bare electrode or composite) give a new way to boost supercapacitor performances in higher specific capacitance, high energy density, and good durability. This review comprehensively summarizes the up-to-date progress in C-QD applications either in a bare condition or as a composite with other materials for supercapacitors. The current state of the three distinct C-QD families used for supercapacitors including carbon quantum dots, carbon dots, and graphene quantum dots is highlighted. 
  • 3.4K
  • 28 Sep 2021
Topic Review
Engine Control Unit
An engine control unit (ECU), also commonly called an engine control module (ECM) is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by reading values from a multitude of sensors within the engine bay, interpreting the data using multidimensional performance maps (called lookup tables), and adjusting the engine actuators. Before ECUs, air–fuel mixture, ignition timing, and idle speed were mechanically set and dynamically controlled by mechanical and pneumatic means. If the ECU has control over the fuel lines, then it is referred to as an electronic engine management system (EEMS). The fuel injection system has the major role of controlling the engine's fuel supply. The whole mechanism of the EEMS is controlled by a stack of sensors and actuators.
  • 3.4K
  • 14 Oct 2022
Topic Review
Bongo Drum
Bongos (Spanish: bongó) are an Afro-Cuban percussion instrument consisting of a pair of small open bottomed hand drums of different sizes. They are struck with both hands, most commonly in an eight-stroke pattern called martillo (hammer). They are mainly employed in the rhythm section of son cubano and salsa ensembles, often alongside other drums such as the larger congas and the stick-struck timbales. Bongo drummers (bongoseros) emerged as the only drummers of son cubano ensembles in eastern Cuba toward the end of the 19th century. The instrument remained important as son groups evolved into larger conjuntos and orchestras in Havana in the 1940s, at which point they began to share the stage with congas. Bongos later reached the United States, where they are commonly played in salsa, Afro-Cuban jazz, Latin rock and other genres. Bongo drums are about 20 centimetres (8 in) high and have diameters of approximately 20 centimetres (8 in) and 25 centimetres (10 in) (the smaller drum is called macho, male, and the larger drum, hembra, female). They are the smallest drums in Latin percussion, some models being only 15 centimetres (6 in) in diameter. The shells of the drums and the bridge (the small block that joins them) are usually made of wood, although fiberglass is also common. The heads are typically made of calfskin and attached to the shells via steel hardware that enables their tuning. Originally, metal tacks were used, so tuning had to be done by heating the skins.
  • 3.4K
  • 02 Nov 2022
Topic Review
Reclaimed Water
Reclaimed or recycled water (also called wastewater reuse or water reclamation) is the process of converting wastewater into water that can be reused for other purposes. Reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater (i.e., groundwater recharge). Reused water may also be directed toward fulfilling certain needs in residences (e.g. toilet flushing), businesses, and industry, and could even be treated to reach drinking water standards. This last option is called either "direct potable reuse" or "indirect potable" reuse, depending on the approach used. Reclaiming water for reuse applications instead of using freshwater supplies can be a water-saving measure. When used water is eventually discharged back into natural water sources, it can still have benefits to ecosystems, improving streamflow, nourishing plant life and recharging aquifers, as part of the natural water cycle. Wastewater reuse is a long-established practice used for irrigation, especially in arid countries. Reusing wastewater as part of sustainable water management allows water to remain as an alternative water source for human activities. This can reduce scarcity and alleviate pressures on groundwater and other natural water bodies.
  • 3.4K
  • 24 Oct 2022
Topic Review
Ghazal
The ghazal (Bengali: গজল, Sylheti: ꠊꠏꠟ, Punjabi: ਗ਼ਜ਼ਲ, Urdu: غزَل , Hindi: ग़ज़ल, Persian: غزل‎, Azerbaijani: qəzəl, Turkish: gazel, Uzbek: gʻazal, Pashto: غزل‎, Template:Lang-gu,) is a form of amatory poem or ode, originating in Arabic poetry. A ghazal may be understood as a poetic expression of both the pain of loss or separation and the beauty of love in spite of that pain. The ghazal form is ancient, tracing its origins to 7th-century Arabic poetry. The ghazal spread into South Asia in the 12th century due to the influence of Sufi mystics and the courts of the new Islamic Sultanate, and is now most prominently a form of poetry of many languages of the Indian subcontinent and Turkey. A ghazal commonly consists of between five and fifteen couplets, which are independent, but are linked – abstractly, in their theme; and more strictly in their poetic form. The structural requirements of the ghazal are similar in stringency to those of the Petrarchan sonnet. In style and content, due to its highly allusive nature, the ghazal has proved capable of an extraordinary variety of expression around its central themes of love and separation.
  • 3.3K
  • 24 Nov 2022
Topic Review
Stress and Strain Induced Transformations
Displacive stress and strain induced transformations are those transformations that occur when the formation of martensite or bainitic ferrite is promoted by the application of stress or strain. These transformations have been shown to be one of the mechanisms by which the mechanical properties of a microstructure can be improved, as they lead to a better ductility and strength by the transformation induced plasticity effect. 
  • 3.3K
  • 08 Mar 2021
Topic Review
Surfactants versus Biosurfactants
Based on their origin and composition, surfactants can be divided into three different categories: (i) synthetic surfactants; (ii) bio-based surfactants; and (iii) microbial biosurfactants. The first group is the most widespread and cost-effective. It is composed of surfactants, which are synthetically produced, using non-renewable sources, with a final structure that is different from the natural components of living cells. The second category comprises surfactants of intermediate biocompatibility, usually produced by chemical synthesis but integrating fats, sugars or amino acids obtained from renewable sources into their structure. Finally, the third group of surfactants, designated as microbial biosurfactants, are considered the most biocompatible and eco-friendly, as they are produced by living cells, mostly bacteria and yeasts, without the intermediation of organic synthesis.
  • 3.3K
  • 14 Mar 2021
Biography
Kevin Systrom
Kevin York Systrom (born December 30, 1983)[1] is an American entrepreneur and programmer, best known as the co‑founder of Instagram along with Mike Krieger. Systrom was born in 1983 in Holliston, Massachusetts. He is the son of Diane (Pels), a marketing executive at Zipcar, who also worked at Monster and Swapit during the first dotcom bubble,[2] and Douglas Systrom, Vice President in Human
  • 3.3K
  • 30 Nov 2022
Topic Review
Eurostar
Eurostar is an international high-speed rail service connecting the United Kingdom with France , Belgium and the Netherlands. Most Eurostar trains travel through the Channel Tunnel between the United Kingdom and France, owned and operated separately by Getlink. The London terminus is London St Pancras International; the other British calling points are Ebbsfleet International and Ashford International in Kent. Intermediate calling points in France are Calais-Fréthun and Lille-Europe. Trains to Paris terminate at Gare du Nord. Trains to Belgium and the Netherlands serve Brussels-South and Rotterdam Centraal, before terminating at Amsterdam Centraal. Additionally, in France there are direct services from London to Marne-la-Vallée–Chessy (Disneyland Paris) and seasonal direct services to southern France (Lyon, Avignon and Marseille) in summer, and to the French Alps in winter. The service is operated by 11 Class 373/1 trainsets, each with 18 coaches, and 17 Class 374 trainsets, each with 16 coaches. The trains run at up to 320 kilometers per hour (200 mph) on high-speed lines. The LGV Nord high-speed line in France opened before Eurostar services began in 1994, and newer lines enabling faster journeys were added later: HSL 1 in Belgium and High Speed 1 in south-east England. The French and Belgian parts of the network are shared with Paris–Brussels Thalys services and TGV trains. Eurostar is operated by Eurostar International Limited (EIL), jointly owned by SNCF, the national railway of France (55%), investment firms (40%), and the National Railway Company of Belgium (5%).
  • 3.3K
  • 20 Nov 2022
Topic Review
Pot-in-pot Refrigerator
A pot-in-pot refrigerator, clay pot cooler or zeer (Arabic: زير) is an evaporative cooling refrigeration device which does not use electricity. It uses a porous outer earthenware pot (lined with wet sand) containing an inner pot (which can be glazed to prevent penetration by the liquid) within which the food is placed. The evaporation of the outer liquid draws heat from the inner pot. The device can cool any substance, and requires only a flow of relatively dry air and a source of water.
  • 3.3K
  • 09 Oct 2022
Topic Review
BM-30 Smerch
The BM-30 Smerch (Russian: Смерч, "tornado", "whirlwind"), 9K58 Smerch or 9A52-2 Smerch-M is a Soviet heavy multiple rocket launcher. The system is intended to defeat personnel, armored, and soft targets in concentration areas, artillery batteries, command posts and ammunition depots. It was designed in the early 1980s and entered service in the Soviet Army in 1989. When first observed by the West in 1983, it received the code MRL 280mm M1983. It is expected to be superseded by the 9A52-4 Tornado.
  • 3.2K
  • 15 Nov 2022
Topic Review
LCD Projector
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD (liquid-crystal display) projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels (combination of polarizer, LCD panel and analyzer), individual pixels can be opened to allow light to pass or closed to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image. Metal-halide lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area; current projectors average about 2,000 to 15,000 American National Standards Institute (ANSI) lumens. Other technologies, such as Digital Light Processing (DLP) and liquid crystal on silicon (LCOS) are also becoming more popular in modestly priced video projection.
  • 3.2K
  • 04 Nov 2022
Topic Review
Weapons of the Cambodian–Vietnamese War
This article is about the weapons used in the Cambodian–Vietnamese War, involved the Vietnam (Army: People's Army of Vietnam (PAVN)), People's Republic of Kampuchea (Army: Kampuchean People's Revolutionary Armed Forces (KPRAF)) which of the Khmer Rouge (Army:Kampuchean Revolutionary Army), Khmer People's National Liberation Front (Army: Khmer People's National Liberation Armed Forces), FUNCINPEC and Thailand (Army: Royal Thai Armed Forces (Thai: กองทัพไทย; RTGS: Kong Thap Thai)) (border clashes) From Vietnam and People's Republic of Kampuchea supported by Soviet Union and other country socialist. From Khmer Rouge supported by China , Khmer People's National Liberation Front and FUNCINPEC supported by United States and United Kingdom
  • 3.2K
  • 22 Nov 2022
Topic Review
Control Rod
Control rods are used in nuclear reactors to control the rate of fission of the nuclear fuel – uranium or plutonium. Their compositions include chemical elements such as boron, cadmium, silver, hafnium, or indium, that are capable of absorbing many neutrons without themselves fissioning. These elements have different neutron capture cross sections for neutrons of various energies. Boiling water reactors (BWR), pressurized water reactors (PWR), and heavy-water reactors (HWR) operate with thermal neutrons, while breeder reactors operate with fast neutrons. Each reactor design can use different control rod materials based on the energy spectrum of its neutrons.
  • 3.2K
  • 11 Nov 2022
Topic Review
Tobacco Products
Tobacco is the agricultural product of the leaves of plants in the genus Nicotiana. All species of Nicotiana contain the addictive drug nicotine—a stimulant and sedative contained in all parts of the plants except the seeds—which occurs in varying amounts depending on the species and variety cultivated. See types of tobacco and curing of tobacco for more information. The vast majority of commercially available tobacco is derived from the species Nicotiana tabacum, although it is also produced from Nicotiana alata, and to a lesser extent Nicotiana clevelandii, Nicotiana longiflora, and Nicotiana rustica, among others. N. rustica in particular contains much more nicotine than N. tabacum and other species of Nicotiana, and forms the basis of a number of unique tobacco products, including several preparations used in Latin American shamanic ceremonies. Once tobacco has been grown, harvested, cured, and processed, it is used to produce a number of different products. These are most often consumable; however, tobacco and the nicotine derived from it are also used to create pesticides. Tobacco products can generally be divided into two types: smoked tobacco (see tobacco smoking) and smokeless tobacco. An expert in tobacco and tobacco products — especially pipes, pipe tobacco, and cigars—including their procurement and sale, is called a tobacconist. The health effects of tobacco consumption are discussed in health effects of tobacco.
  • 3.2K
  • 19 Oct 2022
Biography
Hans Albert Einstein
Hans Albert Einstein (/aɪnˈstaɪn, -ˈʃtaɪn/ eyen-STYNE, -⁠SHTYNE; May 14, 1904 – July 26, 1973) was a Swiss-American engineer and educator, the second child and first son of Albert Einstein and Mileva Marić. Hans A. Einstein was a professor of Hydraulic Engineering at the University of California, Berkeley,[1] and was recognized for his research on sediment transport.[2] His papers are
  • 3.2K
  • 27 Dec 2022
Topic Review
Structure from Motion
Structure from Motion (SfM) is a photogrammetric range imaging technique for estimating three-dimensional structures from two-dimensional image sequences that may be coupled with local motion signals. It is studied in the fields of computer vision and visual perception. In biological vision, SfM refers to the phenomenon by which humans (and other living creatures) can recover 3D structure from the projected 2D (retinal) motion field of a moving object or scene.
  • 3.1K
  • 06 Oct 2022
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