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Topic Review
Drop-in Biofuels
Drop-in biofuels have a plant based origin and can be blended gradually into the existing fuel mix. The usage of drop-in biofuels ensures that little to no adjustments are required relative to existing fuel infrastructure. Non drop-in biofuels include alcohols such as (m)ethanol and gaseous fuels which cannot be used in a diesel engine without adjustments. In this study, the potential of drop-in biofuels is addressed. Based on their suitability as a marine fuel and their drop-in character, five drop-in biofuels are selected. These fuels include Fatty Acid Methyl Esters (FAME), Hydrotreated Vegetable Oil (HVO), Fast-Pyrolysis with full hydrodeoxygenation (FP), Hydrothermal Liquefaction with full hydrodeoxygenation (HTL) and Gasification with consequent Fischer–Tropsch synthesis (GFT). 
  • 2.3K
  • 16 Sep 2021
Topic Review
H Bridge
An H bridge is an electronic circuit that switches the polarity of a voltage applied to a load. These circuits are often used in robotics and other applications to allow DC motors to run forwards or backwards. Most DC-to-AC converters (power inverters), most AC/AC converters, the DC-to-DC push–pull converter, most motor controllers, and many other kinds of power electronics use H bridges. In particular, a bipolar stepper motor is almost invariably driven by a motor controller containing two H bridges.
  • 2.3K
  • 24 Oct 2022
Topic Review
Sabot
A sabot (UK: /sæˈboʊ, ˈsæboʊ/, US: /ˈseɪboʊ/) is a structural device used in firearm or cannon ammunition to keep a sub-caliber flight projectile, such as a relatively small bullet or arrow-type projectile, in the center of the barrel when fired, if the bullet has a significantly smaller diameter than the bore diameter of the weapon used. The sabot component in projectile design is more than simply the relatively thin, tough and deformable seal known as a driving band or obturation ring needed to trap propellant gases behind a projectile, and also keep the projectile centered in the barrel, when the outer shell of the projectile is only slightly smaller in diameter than the caliber of the barrel. Driving bands and obturators are used to seal these full-bore projectiles in the barrel because of manufacturing tolerances; there always exists some gap between the projectile outer diameter and the barrel inner diameter, usually a few thousandths of an inch; enough of a gap for high pressure gasses to slip by during firing. Driving bands and obturator rings are made from material that will deform and seal the barrel as the projectile is forced from the chamber into the barrel. Small caliber jacketed bullets do not normally employ driving bands or obturators because the jacket material, for example copper or gilding metal, is deformable enough to serve that function, and the bullet is made slightly larger than the barrel for that purpose, (see full metal jacket bullet and driving band). Sabots certainly use driving bands and obturators, because the same manufacturing tolerance issues exist when sealing the saboted projectile in the barrel, but the sabot itself is a more substantial structural component of the in-bore projectile configuration (Drysdale 1978). Refer to the two APFSDS (armor-piercing fin-stabilized discarding sabot) pictures on the right to see the substantial material nature of a sabot to fill the bore diameter around the sub-caliber arrow-type flight projectile, compared to the very small gap sealed by a driving band or obturator to mitigate what is known classically as windage. More detailed cutaways of the internal structural complexity of advanced APFSDS saboted long rod penetrator projectiles can be found at reference 2.
  • 2.3K
  • 27 Oct 2022
Topic Review
Twinning-Induced Plasticity
Twinning-induced plasticity (TWIP) steel is a second-generation advanced high strength steel grade developed for automotive applications. TWIP steels exhibit an excellent combination of strength and ductility, mainly originating from the activation of deformation twinning.
  • 2.3K
  • 23 Feb 2021
Topic Review Peer Reviewed
Characteristics, Impacts and Trends of Urban Transportation
Economic growth, urban development and the prosperity of the automobile industry have driven a huge shift in global urban transportation from walking to public transportation and then to automobiles. Private mobility has become an important part of residents’ daily trips. Cities, especially automobile-dependent cities, face a variety of negative impacts such as increased commuting distances, higher congestion costs, traffic accidents, traffic pollution including climate change, etc. Therefore, how to balance the relationship between people’s growing demand for private motorization with the development of urbanization, modernization and motorization and the huge economic, social and environmental costs brought about by them, so as to realize the sustainable development of cities and transportation, is the main problem facing cities around the world. The entry focuses on trends in the sustainable development of urban transportation such as restrictions in private car ownership and use, electrification of urban transportation, intelligent transportation systems (including shared mobility, customized buses and Mobility as a Service/MaaS) and transit-oriented development (TOD). China, as the largest global automobile producer and consumer, represents and leads the growth and evolution of other emerging countries.
  • 2.3K
  • 15 Jun 2022
Topic Review
Mechanical Durability of PEM Fuel Cells
The mechanical durability of PEM fuel cells is a significant barrier to commercializing these systems for stationary and transportation power applications. The performance of a PEM fuel cell or stack is affected pointedly by the degradation of its components materials. Performance degradation is unavoidable, but the degradation rate can be minimized by comprehensively understanding degradation and failure mechanisms. Furthermore, the degradation processes of the different components are often interconnected in fuel cells. Therefore, the degradation phenomena of each fuel cell component must be separated, analyzed, and systematically understood to develop novel component materials and build novel cells/stacks that mitigate insufficient fuel cell mechanical durability.
  • 2.3K
  • 01 Aug 2022
Topic Review
Rheinmetall 120 Mm Gun
The Rheinmetall 120 mm gun is a smoothbore tank gun designed and produced by the West German Rheinmetall-DeTec AG company, developed in response to Soviet advances in armor technology and development of new armored threats. Production began in 1974, with the first version of the gun, known as the L/44 as it was 44 calibers long, used on the German Leopard 2 tank and soon produced under license for the American M1A1 Abrams and other tanks. The American version, the M256, uses a coil spring recoil system instead of a hydraulic system. The 120-millimeter (4.7 in) gun has a length of 5.28 meters (17.3 ft), and the gun system weighs approximately 3,317 kilograms (7,313 lb). By 1990, the L/44 was not considered powerful enough to deal with future Soviet armour, which stimulated an effort by Rheinmetall to develop a better main armament. This first involved a 140-millimeter (5.5 in) tank gun named Neue Panzerkanone 140 ("new tank gun 140"), but later turned into a compromise which led to the development of an advanced 120 mm gun, the L/55, based on the same internal geometry as the L/44 and installed in the same breech and mount. The L/55 is 1.32 meters (4.3 ft) longer, giving increased muzzle velocity to ammunition fired through it. As the L/55 retains the same barrel geometry, it can fire the same ammunition as the L/44. This gun was retrofitted into German and Dutch Leopard 2s, and chosen as the main gun of the Spanish Leopard 2E and the Greek Leopard 2HEL. It was tested on the British Challenger 2 as a potential replacement for its current weapon, the rifled L30 120 mm cannon. A variety of ammunition has been developed for use by tanks with guns based on Rheinmetall's original L/44 design. This includes a series of kinetic energy penetrators, such as the American M829 series, and high explosive anti-tank warheads. Recent ammunition includes a range of anti-personnel rounds and demolition munitions. The LAHAT, developed in Israel, is a gun-launched missile which has received interest from Germany and other Leopard 2 users, and is designed to defeat both land armour and combat helicopters. The Israelis also introduced a new anti-personnel munition which limits collateral damage by controlling the fragmentation of the projectile.
  • 2.3K
  • 27 Oct 2022
Topic Review
State of Charge Estimation Techniques for EV Applications
Electric vehicles (EVs) have acquired significant popularity due to their performance and efficiency. EVs are already largely acknowledged as the most promising solutions to global environmental challenges and CO2 emissions. Li-ion batteries are most frequently employed in EVs due to their various benefits. An effective Battery Management System (BMS) is essential to improve the battery's- performance, including charging-discharging control, precise monitoring, heat management, battery safety, and protection, and also an accurate estimation of the State of Charge (SOC). The SOC is required to provide the driver with a precise indication of the remaining range.
  • 2.3K
  • 27 Jun 2022
Topic Review
Sublevel Caving Production Scheduling
Production scheduling determines the most beneficial mining sequence over the life of mine. Developing a schedule that meets all mining aspects can substantially reduce mining costs and increase profitability. Among all underground mining methods, the sublevel caving (SLC) method is a common method with moderate development requirements, high production rate, and high degree of mechanization and flexibility. None of the manual planning methods and heuristic algorithms used in commercial software will lead to a truly optimal schedule. In sublevel caving, mathematical programming models, particularly mixed-integer programming, have been applied to provide an operationally feasible multi-time period's schedule. However, confined blasting conditions, chaotic material flow, and frequent mixing of ore and waste while loading broken ore at the drawpoint make sublevel caving method unique to produce a holistic plan.
  • 2.3K
  • 27 Aug 2021
Topic Review
Shielding of Cosmic Radiation by Fibrous Materials
Cosmic radiation belongs to the challenges engineers have to deal with when further developing space travel. Besides the severe risks for humans due to high-energy particles or waves, the impact of cosmic radiation on electronics and diverse materials cannot be neglected, even in microsatellites or other unmanned spacecraft. Here, we explain the different particles or waves found in cosmic radiation and their potential impact on biological and inanimate matter.
  • 2.3K
  • 20 Oct 2021
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