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Topic Review
UAVs in the U.S. Military
As of January 2014, the U.S. military operates a large number of unmanned aerial systems (UAVs or Unmanned Air Vehicles): 7,362 RQ-11 Ravens; 990 AeroVironment Wasp IIIs; 1,137 AeroVironment RQ-20 Pumas; and 306 RQ-16 T-Hawk small UAS systems and 246 Predators and MQ-1C Grey Eagles; 126 MQ-9 Reapers; 491 RQ-7 Shadows; and 33 RQ-4 Global Hawk large systems. The military role of unmanned aircraft systems is growing at unprecedented rates. In 2005, tactical- and theater-level unmanned aircraft alone had flown over 100,000 flight hours in support of Operation Enduring Freedom and Operation Iraqi Freedom, in which they are organized under Task Force Liberty in Afghanistan and Task Force ODIN in Iraq. Rapid advances in technology are enabling more and more capability to be placed on smaller airframes, which is spurring a large increase in the number of Small Unmanned Aircraft Systems (SUAS) being deployed on the battlefield. The use of SUAS in combat is so new that no formal DoD wide reporting procedures have been established to track SUAS flight hours. As the capabilities grow for all types of UAS, nations continue to subsidize their research and development, leading to further advances and enabling them to perform a multitude of missions. UAS no longer only perform intelligence, surveillance, and reconnaissance missions, although this still remains their predominant type. Their roles have expanded to areas including electronic attack, drone strikes, suppression or destruction of enemy air defense, network node or communications relay, combat search and rescue, and derivations of these themes. These UAS range in cost from a few thousand dollars to tens of millions of dollars, with aircraft ranging from less than one pound to over 40,000 pounds.
  • 3.1K
  • 14 Oct 2022
Topic Review
In-Wheel Motor Drive Systems for Electric Vehicles
There has been significant attention given to the electrification of transportation due to concerns about fossil fuel depletion and environmental pollution. Conventional drive systems typically include a clutch, reduction gear, and mechanical differential, which results in power loss, noise, vibration, and additional maintenance. However, in-wheel motor drive technology eliminates the need for these components, providing benefits such as higher system efficiency, improved wheel control, and increased passenger comfort.
  • 3.1K
  • 21 Aug 2023
Topic Review
Redoutable-Class Submarine (1931)
The Redoutable-class submarines were a group of 31 submarines built between 1924 and 1937 for the French Navy. Most of the class saw service during the Second World War. The class is also known in French as the Classe 1 500 tonnes, and they were designated as "First Class submarines", or "large submarine cruisers". They are known as the Redoutable class in reference to the lead boat Redoutable, in service from 1931 to 1942. The class is divided into two sub-class series, Type I, known as Le Redoutable and Type II, Pascal. Modern submarines when they were designed, they quickly became outdated, and were approaching obsolescence by the beginning of the Second World War. The conditions of the Armistice of 22 June 1940 prevented the Vichy government from carrying out a modernization programme. 24 out of the 29 units that served in the war were lost. Used in the defence of the Second French colonial empire under the Vichy regime, submarines of the class saw action against Allied offensives at the Battles of Dakar, Libreville and Madagascar. Many of the submarines of the class came under Allied control after the Allied landings in North Africa. Few however saw much further active service after this due to a period of refitting and alterations done in the United States between February 1943 and March 1945. One exception was Casabianca, which took part in the liberation of Corsica. The surviving submarines were largely used for training purposes after the war, with the last of them being disarmed in 1952.
  • 3.1K
  • 29 Nov 2022
Topic Review
Electron (Rocket)
Electron is a two-stage orbital expendable launch vehicle (with an optional third stage) developed by the American aerospace company Rocket Lab to service the commercial small satellite launch segment. Its Rutherford engines, manufactured in California , are the first electric-pump-fed engine to power an orbital rocket. In December 2016, Electron completed flight qualification. The first rocket was launched on 25 May 2017, reaching space but not achieving orbit due to a glitch in communication equipment on the ground. During its second flight on 21 January 2018, Electron reached orbit and deployed three CubeSats. The first commercial launch of Electron, and the third launch overall, occurred on 11 November 2018.
  • 3.0K
  • 08 Oct 2022
Topic Review
Solar Radiation Management
Solar radiation management (SRM) proposals are a type of climate engineering which would seek to reflect sunlight and thus reduce global warming. Proposed methods include increasing the planetary albedo, for example using stratospheric sulfate aerosols. Restorative methods have been proposed regarding the protection of natural heat reflectors like sea ice, snow and glaciers with engineering projects. Their principal advantages as an approach to climate engineering is the speed with which they can be deployed and become fully active, their potential low financial cost, and the reversibility of their direct climatic effects. Solar radiation management projects could serve as a temporary response while levels of greenhouse gases can be brought under control by mitigation and greenhouse gas removal techniques. They would not reduce greenhouse gas concentrations in the atmosphere, and thus do not address problems such as ocean acidification caused by excess carbon dioxide (CO2).
  • 3.0K
  • 24 Nov 2022
Topic Review
Military Transport Aircraft
Military transport aircraft or military cargo aircraft are typically fixed wing and rotary wing cargo aircraft which are used to airlift troops, weapons and other military equipment by a variety of methods to any area of military operations around the surface of the planet, usually outside the commercial flight routes in uncontrolled airspace. Originally derived from bombers, military transport aircraft were used for delivering airborne forces during World War II and towing military gliders. Some military transport aircraft are tasked to perform multi-role duties such as aerial refueling and, rescue missions, tactical, operational and strategic airlifts onto unprepared runways, or those constructed by engineers.
  • 3.0K
  • 20 Oct 2022
Topic Review
Schweizer 300
The Schweizer RSG 300 series (formerly Sikorsky S300, Hughes 300 and Schweizer 300) family of light utility helicopters was originally produced by Hughes Helicopters, as a development of the Hughes 269. Later manufactured by Schweizer Aircraft, the basic design has been in production for almost 50 years. The single, three-bladed main rotor and piston-powered S-300 is mostly used as a cost-effective platform for training and agriculture.
  • 2.9K
  • 08 Nov 2022
Topic Review
Trace Gas Orbiter
The ExoMars Trace Gas Orbiter (TGO or ExoMars Orbiter) is a collaborative project between the European Space Agency (ESA) and Roscosmos that sent an atmospheric research orbiter and the Schiaparelli demonstration lander to Mars in 2016 as part of the European-led ExoMars programme. The Trace Gas Orbiter delivered the Schiaparelli lander on 16 October 2016, which crashed on the surface. The orbiter began aerobraking in March 2017 to lower its initial orbit of 200 by 98,000 km (120 by 60,890 mi). Aerobraking concluded on 20 February 2018 when a final thruster firing resulted in an orbit of 200 by 1,050 km (120 by 650 mi). Additional thruster firings every few days raised the orbiter to a circular "science" orbit of 400 km (250 mi), which was achieved on 9 April 2018. A key goal is to gain a better understanding of methane (CH4) and other trace gases present in the Martian atmosphere that could be evidence for possible biological activity. The programme will follow with the Kazachok lander and the Rosalind Franklin rover in 2020, which will search for biomolecules and biosignatures; the TGO will operate as the communication link for the ExoMars lander and rover and provide communication for other Mars surface probes with Earth.
  • 2.9K
  • 27 Oct 2022
Topic Review
Sensor Fusion Technology in Autonomous Vehicles
Complete autonomous systems such as self-driving cars to ensure the high reliability and safety of humans need the most efficient combination of four-dimensional (4D) detection, exact localization, and artificial intelligent (AI) networking to establish a fully automated smart transportation system. Sensor fusion also called multisensory data fusion or sensor data fusion is used to improve the specific detection task. In AVs, the primary sensors of cameras, radio detection and ranging (RADAR), and light detection and ranging (LiDAR) are used for object detection, localization, and classification.
  • 2.9K
  • 17 Jan 2024
Topic Review
Man-lifting Kite
right|thumb|Man-lifter War Kite designed by Samuel Franklin Cody (1867–1913).thumb|Lawrence Hargrave (seated) with his man-lifting kites in Stanwell Park, 1894. A man-lifting kite is a kite designed to lift a person from the ground. Historically, man-lifting kites have been used chiefly for reconnaissance and entertainment. Interest in their development declined with the advent of powered flight at the beginning of the 20th century.
  • 2.9K
  • 13 Oct 2022
Topic Review
Regulation of Unmanned Aerial Vehicles
The use of unmanned aerial vehicles (UAVs) is generally regulated by the national aviation authority of the country.
  • 2.9K
  • 31 Oct 2022
Topic Review
NEC Engineering and Construction Contract
The New Engineering Contract (NEC), or NEC Engineering and Construction Contract, is a formalised system created by the UK Institution of Civil Engineers that guides the drafting of documents on civil engineering and construction projects for the purpose of obtaining tenders, awarding and administering contracts. As such they legally define the responsibilities and duties of Employers (who commission work) and Contractors (who carry out work) in the Works Information. The contract consists of two key parts the Contract Data part one (Data provided by the Employer) and Contract Data part two (Data provided by the Contractor). Several approaches are included making it a family of options. It is used in the UK and internationally in countries including New Zealand, Australia , Hong Kong and South Africa . There have been four editions, the first in 1993, the second in 1995, the third in 2005 and the most recent in 2017. The NEC3 was launched in 2005 and it was amended in April 2013. NEC4 was announced in March 2017 and has been available since June 2017. This new edition reflects procurement and project management developments and emerging best practice, with improvements in flexibility, clarity and the ease of administration. It also introduces two new contracts: NEC4 Design, Build and Operate (DBO) and NEC4 Alliance Contract (ALC).
  • 2.8K
  • 28 Sep 2022
Topic Review
Communication-based Train Control(CBTC) System
Nowadays, the communication-based train control(CBTC) system is commonly used in the urban rail transit system all over the world, and the CBTC systems currently operating worldwide are the "Products" of advances in Internet of Things and Artificial Intelligence. 
  • 2.8K
  • 04 Apr 2022
Topic Review
Amsterdam (VOC Ship)
The Amsterdam (Dutch pronunciation: [ˌɑmstərˈdɑm] (listen)) was an 18th-century cargo ship of the Dutch East India Company (Dutch: Vereenigde Oost-Indische Compagnie; VOC). The VOC was established in 1602. The ship started its maiden voyage from Texel to Batavia on 8 January 1749, but was wrecked in a storm on the English Channel on 26 January 1749. The shipwreck was discovered in 1969 in the bay of Bulverhythe, near Hastings on the English south coast, and is sometimes visible during low tides. The wreck site is protected under the Protection of Wrecks Act since 1974. Some of the findings from the site are in The Shipwreck Museum in Hastings. A replica of the ship is on display in Amsterdam.
  • 2.8K
  • 01 Dec 2022
Topic Review
Tanks in France
French development into tanks began during World War I as an effort to overcome the stalemate of trench warfare, and largely at the initiative of the manufacturers. The Schneider CA1 was the first tank produced by France, and 400 units were built. The French also experimented with various tank designs, such as the Frot-Laffly landship, Boirault machine and Souain experiment. Another 400 Saint-Chamond tanks were manufactured from April 1917 to July 1918, however these tanks were largely underpowered and of limited utility due to the design of the caterpillar tracks, which were too short in comparison with the tank's length and weight. The most significant French tank development during the war was the Renault FT light tank, which set the general layout for future tank designs and was used or redesigned by various military forces, including those of the United States.
  • 2.8K
  • 03 Nov 2022
Topic Review
Waka (Canoe)
Waka (Māori: [ˈwaka]) are Māori watercraft, usually canoes ranging in size from small, unornamented canoes (waka tīwai) used for fishing and river travel to large, decorated war canoes (waka taua) up to 40 metres (130 ft) long. The earliest remains of a canoe in New Zealand were found near the Anaweka estuary in a remote part of the Tasman District and radiocarbon-dated to about 1400. The canoe was constructed in New Zealand, but was a sophisticated canoe, compatible with the style of other Polynesian voyaging canoes at that time. Since the 1970s about eight large double-hulled canoes of about 20 metres have been constructed for oceanic voyaging to other parts of the Pacific. They are made of a blend of modern and traditional materials, incorporating features from ancient Melanesia, as well as Polynesia.
  • 2.8K
  • 13 Oct 2022
Topic Review
HVAC
Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels and senior living facilities, medium to large industrial and office buildings such as skyscrapers and hospitals, on ships and submarines, and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors. Ventilating or ventilation (the V in HVAC) is the process of exchanging or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and other gases. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air. Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.
  • 2.8K
  • 10 Nov 2022
Topic Review
Electric Vehicle Charging Systems
The high-voltage battery is a crucial element for electric vehicles (EVs) traction systems. It is the primary energy source that must be regularly recharged to reach the autonomy declared by the manufacturer. Therefore, an EV charging system is required to ensure the battery charging process. 
  • 2.8K
  • 27 Feb 2023
Topic Review
List of Tall Ships
A list of tall ships afloat as of March 2012, listed alphabetically by vessel name:
  • 2.8K
  • 24 Nov 2022
Topic Review
Chrysler Pacifica (RU)
The Chrysler Pacifica is a minivan being produced by the Chrysler division of FCA US LLC. Despite sharing its name with a discontinued crossover, it is an all-new design replacing the Chrysler Town & Country. The minivan is produced with two powertrains, a 3.6-liter gasoline powered engine and a plug-in hybrid, marketed as Pacifica Hybrid. The plug-in hybrid version has a 16-kWh lithium-ion battery that can propel the car up to 33 mi (53 km) on electric power alone. The gasoline-only version of the Pacifica minivan went on sale in mid-2016, while the plug-in hybrid version became available in early 2017.
  • 2.8K
  • 17 Oct 2022
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