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Topic Review
Flat Twin Engine
A flat-twin is a two-cylinder internal combustion engine with the cylinders on opposite sides of the crankshaft. It is a flat engine with two cylinders. Used in motorcycles for more than a century, flat-twins have also been used in automobiles, light aircraft, stationary powerplants, and household appliances. Early flat-twin motorcycles' engines were mounted with the cylinders in line with the frame. This caused uneven cooling of the cylinders and required the motorcycle to have a long wheelbase. Later flat-twin motorcycles' engines were mounted with their cylinders across the frame for better air cooling and a shorter wheelbase. Disadvantages of this layout include torque reaction in the motorcycle in turns and the potential to damage cylinder heads.
  • 2.6K
  • 27 Oct 2022
Topic Review
Transmission (Mechanics)
A transmission is a machine in a power transmission system, which provides controlled application of power. Often the term 5-speed transmission refers simply to the gearbox, that uses gears and gear trains to provide speed and torque block conversions from a rotating power source to another device. The term transmission properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differential, and final drive shafts. In the United States the term is sometimes used in casual speech to refer more specifically to the gearbox alone, and detailed usage differs. The most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a relatively high rotational speed, which is inappropriate for starting, stopping, and slower travel. The transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are also used on pedal bicycles, fixed machines, and where different rotational speeds and torques are adapted. Often, a transmission has multiple gear ratios (or simply "gears") with the ability to switch between them as the speed varies. This switching may be done manually (by the operator) or automatically (by a control unit). Directional (forward and reverse) control may also be provided. Single-ratio transmissions also exist, which simply change the speed and torque (and sometimes direction) of motor output. In motor vehicles, the transmission generally is connected to the engine crankshaft via a flywheel or clutch or fluid coupling, partly because internal combustion engines cannot run below a particular speed. The output of the transmission is transmitted via the driveshaft to one or more differentials, which drive the wheels. While a differential may also provide gear reduction, its primary purpose is to permit the wheels at either end of an axle to rotate at different speeds (essential to avoid wheel slippage on turns) as it changes the direction of rotation. Conventional gear/belt transmissions are not the only mechanism for speed/torque adaptation. Alternative mechanisms include torque converters and power transformation (e.g. diesel-electric transmission and hydraulic drive system). Hybrid configurations also exist. Automatic transmissions use a valve body to shift gears using fluid pressures in response to engine RPM, speed, and throttle input.
  • 2.6K
  • 01 Nov 2022
Topic Review
International Roughness Index
The International Roughness Index (IRI) is the roughness index most commonly obtained from measured longitudinal road profiles. It is calculated using a quarter-car vehicle math model, whose response is accumulated to yield a roughness index with units of slope (in/mi, m/km, etc.). This performance measure has less stochasticity and subjectivity in comparison to other pavement performance indicators, but it is not completely devoid of randomness. The sources of variability in IRI data include the difference among the readings of different runs of the test vehicle and the difference between the readings of the right and left wheel paths. Despite these facts, since its introduction in 1986, the IRI has become the road roughness index most commonly used worldwide for evaluating and managing road systems. The measurement of IRI is required for data provided to the United States Federal Highway Administration, and is covered in several standards from ASTM International: ASTM E1926 - 08, ASTM E1364 - 95(2005), and others. IRI is also used to evaluate new pavement construction, to determine penalties or bonus payments based on smoothness.
  • 2.6K
  • 31 Oct 2022
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.
  • 2.5K
  • 15 Jun 2022
Topic Review
High-Speed Train Noise Control Methods
The sound of trains is considered a disturbance to most residents around the railroad and train passengers, and the sound generated by trains can interfere with sleep, life, and work. With increases in train speed, the main noise from high-speed trains has changed from rolling noise to aerodynamic noise, and the noise level and noise frequency range have also changed significantly. The current methods of noise reduction for trains are discussed.
  • 2.5K
  • 09 Aug 2022
Topic Review
Diamond DA42
The Diamond DA42 Twin Star is a four seat, twin engine, propeller-driven airplane developed and manufactured by Austrian company Diamond Aircraft Industries. It was Diamond's first twin engine design, as well as the first new European twin-engine aircraft in its category to be developed in over 25 years. In 2004, the DA42 became the first diesel-powered fixed-wing aircraft to perform a non-stop crossing of the North Atlantic. By 2012, the DA42 had become a key revenue generator for the company, having gained popularity with government and military operators in addition to the civil market that had suffered as a result of the Great Recession. Government customers have typically employed the type in the aerial surveillance role, which contributed towards the development of the Aeronautics Defense Dominator, a medium-altitude long-endurance (MALE) unmanned aerial vehicle (UAV), which had been derived from the DA42.
  • 2.5K
  • 21 Nov 2022
Topic Review
BMW 7 Series (E65)
The BMW E65 is the fourth generation of the BMW 7 Series range of full-size luxury sedans, and was produced from 2001 to 2008. The variants of the range are: The E65 was the first BMW vehicle to include the iDrive infotainment system, the new brand design language, active anti-roll bars, a 6-speed automatic transmission, an electronic smart Key (dispensing with the traditional metallic key), and night vision. The 760i model also utilised the world's first production V12 engine to use direct injection. In late 2008, the E65 7 Series was replaced by the 7 Series (F01).
  • 2.5K
  • 11 Nov 2022
Topic Review
Digital Technology Adopted by Airlines during COVID-19 Pandemic
Airlines’ major adoption of digital technology during the COVID-19 crisis may have changed how customers experience the services and may affect passengers’ perceptions compared to the past. The pandemic has forced the airline industry to change and adopt new business strategies. Apart from ensuring business continuity, passengers also have higher expectations. Maintaining the same level of service standards as in the pre-pandemic era may be insufficient to retain passengers’ satisfaction with the airlines. Passengers are now more stringent with health and hygiene. New digital technology can assist the airline industry in overcoming the challenges posed by the crisis. During the pandemic period, many airlines have strengthened their digital technology capability, significantly accelerating transformation and innovation to digitalization.
  • 2.4K
  • 15 Dec 2022
Topic Review
IKCO EF Engines
IKCO EF engines are a family of four-cylinder engines. The EF7 series are designed jointly by Iran Khodro Powertrain Company (IPCO) and F.E.V GmbH of Germany. The other models will be designed by IPCO itself. IPCO is the powertrain designing & producing company of Iranian car manufacturer Iran Khodro (IKCO). IKCO aims to supply 800,000 powertrains by 2010. The first phase of IKCO EF Engines project (EF7 Dual-Fuel) investments were about 80 million US$. EF4 & EF7 engines use CNG as their main fuel and they can also use gasoline. EFD is the first engine of the EF family that is single-fuel. It uses high-quality diesel (Euro 4 Quality or better) as fuel. EF engines share most of their parts between them. It was IKCO's aim to reduce costs and provide ease of supplying the parts in the future for after-sales services. The EF family dual-fuel and petrol-fuel engines have achieved the Euro IV emission standard and are able to achieve Euro V emission standard with some minor changes but EFD will be the first engine of the family which comes with the Euro IV emission standard as its first release, and is able to achieve the Euro VI emission standard with some changes. The most important suppliers for EF engines are INA for sensitive VVT parts and some other mechanical parts, MAHLE which supplies some important parts of the engine family such as pistons, with Bosch supplying the ECU and electrically controlled pedal and lots of other important sensitive electronic parts. Almost all of the parts (except high-tech and sensitive parts) from worldwide well-known companies (as mentioned) are produced in Iran under license with the highest required quality for the engines. The Germany company Bosch had shown interest in assembling the Iranian engine under license. In 2008 IKCO has announced that EF7 is among the three best CNG-based engines of the world in designing.
  • 2.4K
  • 01 Dec 2022
Topic Review
Kepler (Spacecraft)
Kepler is a space observatory launched by NASA to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched on March 7, 2009, into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. Designed to survey a portion of our region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitors the brightness of approx 150,000 main sequence stars in a fixed field of view. These data are transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Kepler is part of NASA's Discovery Program of relatively low-cost, focused primary science missions. The telescope's construction and initial operation were managed by NASA's Jet Propulsion Laboratory, with Ball Aerospace responsible for developing the Kepler flight system. The Ames Research Center is responsible for the ground system development, mission operations since December 2009, and scientific data analysis. The initial planned lifetime was 3.5 years, but greater-than-expected noise in the data, from both the stars and the spacecraft, meant additional time was needed to fulfill all mission goals. Initially, in 2012, the mission was expected to be extended until 2016, but on July 14, 2012, one of the spacecraft's four reaction wheels used for pointing the spacecraft stopped turning, and completing the mission would only be possible if all other reaction wheels remained reliable. Then, on May 11, 2013, a second reaction wheel failed, disabling the collection of science data and threatening the continuation of the mission. On August 15, 2013, NASA announced that they had given up trying to fix the two failed reaction wheels. This meant the current mission needed to be modified, but it did not necessarily mean the end of planet hunting. NASA had asked the space science community to propose alternative mission plans "potentially including an exoplanet search, using the remaining two good reaction wheels and thrusters". On November 18, 2013, the K2 "Second Light" proposal was reported. This would include utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs. On May 16, 2014, NASA announced the approval of the K2 extension. (As of January 2015), Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 star systems, along with a further 3,199 unconfirmed planet candidates.[upper-alpha 2] Four planets have been confirmed through Kepler's K2 mission. In November 2013, astronomers estimated, based on Kepler space mission data, that there could be as many as 40 billion rocky, Earth-size exoplanets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. It is estimated that 11 billion of these planets may be orbiting Sun-like stars. The nearest such planet may be 3.7 parsecs (12 ly) away, according to the scientists. On January 6, 2015, NASA announced the 1,000th confirmed exoplanet discovered by the Kepler Space Telescope. Four of the newly confirmed exoplanets were found to orbit within habitable zones of their related stars: three of the four, Kepler-438b, Kepler-442b and Kepler-452b, are almost Earth-size and likely rocky; the fourth, Kepler-440b, is a super-Earth. On May 10, 2016, NASA verified 1,284 new exoplanets found by Kepler, the single largest finding of planets to date. Kepler data has also helped scientists observe and understand supernovae; measurements were collected every half-hour so the light curves were especially useful for studying these types of astronomical events.
  • 2.4K
  • 20 Oct 2022
Topic Review
List of Human Spaceflight Programs
This is a list of human spaceflight programs, including successful programs, programs that were canceled, and programs planned for the future. The criteria for what constitutes human spaceflight vary. The FAI defines spaceflight as any flight over 100 kilometers (62 mi). In the U.S. professional, military, and commercial astronauts who travel above an altitude of 80 kilometers (50 mi) are awarded astronaut wings. This article follows the FAI definition of spaceflight. Until the 21st century, human spaceflight programs were sponsored exclusively by governments, through either the military or civilian space agencies. With the launch of the privately funded SpaceShipOne in 2004, a new category of human spaceflight programs – commercial human spaceflight – arrived.
  • 2.3K
  • 09 Nov 2022
Topic Review
Industry 4.0 in Supply Chain
Industry 4.0 is better known as the fourth industrial revolution and describes a future production system’s vision. In 2011, the idea of Industry 4.0 was first given and implemented by the German government for supporting automation in manufacturing. The fourth industrial revolution (Industry 4.0) focuses on enabling automation to integrate all manufacturing industries’ systems to achieve sustainability. There are many disruptive technologies such as the Internet of things (IoT). This means that all the devices, machines, and processes in supply chains are digitally connected through an internet connection and share the real-time information of all the processes. The Internet of things (IoT) integrates different technologies such as sensors, networks, algorithms, and applications. The IoT enables businesses to improve their supply chain network and gain better productivity. Cyber–physical system (C.P.S.) is another fundamental technology of industry 4.0. C.P.S. can be implemented in many industries such as healthcare, logistics, and automobiles. From an operational view, logistics is the critical function of any business that engages the supply chain movements. A cyber-physical system allows the supply chain network to use networking, computation, and physical processes to add value in the production process to achieve competitiveness. Another concept of Industry 4.0 concerns automatic guided vehicles (A.G.V.), which are widely used by many companies.
  • 2.3K
  • 01 Sep 2021
Topic Review
Motorcycle Market
In many cities, urbanization has led to a rapid increase in the demand for mobility. Most of this new demand has been satisfied by the individual private transport industry, within which motorcycles have an important share: around 30% of the vehicles in the world are motorcycles. Thus, the motorcycle market has experienced an upward trend, especially in developing countries. That uncontrolled growth brings along mobility, accidents, and environment-related issues that concern policy-makers. Research trends regarding this matter evidence that greenhouse gas emissions, sustainability, environmental impact, and developing countries are the topics of greater interest for researchers. In addition, taking into account the needs of modern cities, sustainable modes of transport such as electric and shared mobility are compulsory as a priority on governments' agendas. 
  • 2.3K
  • 26 Oct 2021
Topic Review
Type 69 RPG
The Type 69 85mm rocket propelled grenade (RPG), made by Norinco, is a Chinese variant of the Soviet RPG-7. First introduced in 1972, the Type 69 is a common individual anti-tank weapon in service with the PLA. More advanced grenade rounds were developed in the 1980s and 1990s to meet the requirements of modern battlefields. Eventually, the aging Type 69 RPG family was replaced by modern anti-tank weapon systems developed by China such as Type 89 and Type 08.
  • 2.3K
  • 08 Nov 2022
Topic Review
El Toro Loco (Truck)
El Toro Loco (Spanish for "The Crazy Bull") is a monster truck currently racing in the Monster Jam series. It is currently driven by Kayla Blood. Other drivers of have included Dan Rodoni, Aaron Basl, Ryan Huffaker, Joey Parnell, Chris Baker, and Nathan Weenk. It features one of the first 3-D body shells, with horns sticking out of the roof. This body was originally designed for Bulldozer, and was found a second use for El Toro Loco. As El Toro Loco has increased in popularity, it has become the primary truck for the body style.
  • 2.3K
  • 31 Oct 2022
Topic Review
List of Aircraft (P)
This is a list of aircraft in alphabetical order beginning with 'P'.
  • 2.3K
  • 19 Oct 2022
Topic Review
Daihatsu Rocky
The Daihatsu Rocky (Japanese: ダイハツ・ロッキー, Daihatsu Rokkī) is an automobile nameplate used by Daihatsu for their lineup of SUVs. The nameplate was originally used as a ladder frame-based mini SUV that was sold in Japan and some international markets between 1989 and 2002. It was gradually replaced by the introduction of Terios in 1997. Beginning in 2019, the Rocky nameplate returned to Japan as a subcompact crossover SUV that replaces the Be‣go and is also rebadged and sold under Toyota brand as the Toyota Raize (Japanese: トヨタ・ライズ, Toyota Raizu).
  • 2.3K
  • 27 Oct 2022
Topic Review
List of Aircraft (H)
This is a list of aircraft in alphabetical order beginning with 'H'.
  • 2.2K
  • 08 Nov 2022
Topic Review
List of Aircraft in the Smithsonian Institution
The List of aircraft in the Smithsonian Institution includes aircraft exhibited in the Smithsonian Institution's National Air and Space Museum, Steven F. Udvar-Hazy Center, and the Paul E. Garber Preservation, Restoration, and Storage Facility. The Smithsonian Institution's collection of aircraft and spacecraft is the largest on display in the world.
  • 2.2K
  • 21 Oct 2022
Topic Review
Batavia (Ship)
Batavia (Dutch pronunciation: [baːˈtaːviaː] (listen)) was a ship of the Dutch East India Company (VOC). It was built in Amsterdam, Dutch Republic, in 1628, and armed with 24 cast-iron cannons and a number of bronze guns. Batavia was shipwrecked on her maiden voyage, and was made famous by the subsequent mutiny and massacre that took place among the survivors. A twentieth-century replica of the ship is also called the Batavia and can be visited in Lelystad, Netherlands.
  • 2.2K
  • 15 Nov 2022
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