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Topic Review
BMW 6 Series (E24)
The BMW E24 is the first generation of BMW 6 Series grand tourer coupes and was produced from January 1976 to April 1989. It replaced the E9 coupes and was, after a 16-year hiatus, succeeded by the E63 6 Series in 2004. The E24 was produced solely in a 2-door coupe body style. Aside from the M635CSi/M6 models, the E24 was powered by a range of M30 straight-6 engines. The M635CSi is the first of the BMW M6 model line and is the second true "M car" produced after the BMW M1. The M635CSi is powered by the M88/3 straight-6 engine. In North America, the vehicle is badged simply as "M6" and is powered by the detuned S38 straight-6 engine, which has a lower compression ratio and uses a catalytic converter. Although the 8 Series was released as production of the E24 was ending, the 8 Series is considered a separate model line and therefore not a true successor to the E24.
  • 6.0K
  • 18 Oct 2022
Topic Review
Crash Boats of World War 2
Crash boats, at the time known as "aircraft rescue boat" or "air-sea rescue boat" were wooden speedboats built to rescue the crew of downed United States and other Allies aircraft during World War II. US boats came from observation of British experience with High-speed launches during the Battle of Britain. By the end of World War II America had produced 300,000 planes, creating a need to have crash rescue boats stationed around the globe. These boats were fast boats used to rescue pilots, crew and passengers from downed aircraft in search and rescue, air-sea rescue missions. The boats would race out to a crash site and rescue wounded aircrew. Some speed boats built before the war were acquired and converted to be crash boats and many new boats were built. Standard crash boats were built in four lengths for World War II. The smallest standard size boat was 42 feet long. The larger boats were 63 or 85 or 104 feet long. They were built for the Army Air Forces, US Navy and some were transferred to Allies. The design was similar to patrol boats built for the war, but with less or no armament and first aid equipped. The boats were designed to be light and fast to be able to get to the downed aircrew as fast as possible. Most were used in the Pacific war across the vast South Pacific, in the Island hopping campaign. Some were station on the West Coast of the United States to support the vast training centers. Many were designated Air Rescue Boats or ARB or AVR or P or C or R Hull classification symbol. After the war most were abandoned or destroyed, a few served in the Korean war (with United States Air Force ), some sold to private and some donated to Sea Scouts.
  • 5.8K
  • 23 Nov 2022
Topic Review Peer Reviewed
Two-Lane Highways: Indispensable Rural Mobility
Two-lane highways refer to roadways consisting of two lanes in the cross section, one for each direction of travel. Occasionally, passing lanes may be added to one or two sides of the roadway extending the cross section to three or four lanes at those locations. In this entry, two-lane highways strictly refer to roads in rural areas meeting the previous definition and do not include urban and suburban streets.
  • 5.8K
  • 13 Apr 2022
Topic Review
Panzer II Variants
The Panzerkampfwagen II (Pz.Kpfw.II) light tank, produced in Germany in the late 1930s and early 1940s had a wide array of variants, both as development of the light tank and for specialised tasks.
  • 5.8K
  • 02 Nov 2022
Topic Review
DRDO Rustom
The DRDO Rustom (English: Warrior) is a Medium Altitude Long Endurance unmanned air vehicle (UAV) being developed by Defence Research and Development Organisation for the three services, Indian Army, Indian Navy and the Indian Air Force of the Indian Armed Forces. Rustom is derived from the NAL's LCRA (Light Canard Research Aircraft) developed by a team under the leadership of late Prof Rustom Damania in the 1980s. The UAV will have structural changes and a new engine. Rustom will replace/supplement the Heron UAVs in service with the Indian armed forces.
  • 5.7K
  • 02 Nov 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.
  • 5.7K
  • 01 Nov 2022
Topic Review
Autonomous Driving Technologies in Electric Vehicles
In response to severe environmental and energy crises, the world is increasingly focusing on electric vehicles (EVs) and related emerging technologies. Sensory, control, and telematics technologies are the keys to reliable autonomous driving. The integration and complementarity of EVs and autonomous driving will be an important opportunity for future smart transportation and smart cities. 
  • 5.7K
  • 01 Sep 2022
Topic Review
List of Aircraft (P)
This is a list of aircraft in alphabetical order beginning with 'P'.
  • 5.5K
  • 19 Oct 2022
Topic Review
Jagdtiger
The Jagdtiger ("Hunting Tiger"; officially designated Panzerjäger Tiger Ausf. B) is a German casemate-type heavy tank destroyer from World War II. It was built upon the slightly lengthened chassis of a Tiger II. Its ordnance inventory designation was Sd.Kfz. 186. The 71-tonne Jagdtiger was the heaviest armored fighting vehicle (AFV) used operationally by any participant nation of WWII and is the heaviest combat vehicle of any type to achieve series production during the conflict. The vehicle was armed with a 128 mm Pak 44 L/55 main gun which was capable of outranging and defeating any tank or AFV fielded by the Allied forces. It saw brief service in small numbers from late 1944 up until the end of the war on both the Western and Eastern Front. Although 150 were ordered, only around eighty were produced. Due to an excessive weight and a significantly underpowered drivetrain system, the Jagdtiger was continuously plagued with various mobility and mechanical problems. At present, three Jagdtigers survive in different museums around the world.
  • 5.4K
  • 17 Oct 2022
Topic Review
Puma (IFV)
The Puma is a Germany infantry fighting vehicle (IFV) (Schützenpanzer or short SPz) designed to replace the aging Marder IFVs currently in service with the German Army. Production of the first batch of 350 vehicles began in 2010 and is scheduled for completion by the second quarter of 2021. A second batch of 210 Pumas has received funding. Mass production began on 6 July 2009. The companies responsible for this project are Krauss-Maffei Wegmann and Rheinmetall Landsysteme, who created a joint venture in the form of Projekt System Management GmbH (PSM). The Puma is one of the world's best-protected IFVs, while still having a high power-to-weight ratio.
  • 5.3K
  • 28 Sep 2022
Topic Review
Jeep Renegade (BU)
The Jeep Renegade (BU/520) is a subcompact crossover SUV (B-segment) produced by FCA US under their Jeep marque. It was first shown to the public in March 2014 at the Geneva Motor Show and production started in late August of that year. Standard Renegade models come with front-wheel drive. The vehicle offers the four-wheel drive systems Active Drive I and Active Drive Low, both of which are paired with Jeep's Selec-Terrain System.
  • 5.3K
  • 15 Nov 2022
Topic Review
Lane Detection and Tracking
Lane detection and tracking are the advanced key features of the advanced driver assistance system. Lane detection is the process of detecting white lines on the roads. Lane tracking is the process of assisting the vehicle to remain in the desired path, and it controls the motion model by using previously detected lane markers.
  • 5.3K
  • 25 Oct 2021
Topic Review
Cylinder Block
The cylinder block is an integrated structure comprising the cylinder(s) of a reciprocating engine and often some or all of their associated surrounding structures (coolant passages, intake and exhaust passages and ports, and crankcase). The term engine block is often used synonymously with "cylinder block" (although technically distinctions can be made between en bloc cylinders as a discrete unit versus engine block designs with yet more integration that comprise the crankcase as well). In the basic terms of machine elements, the various main parts of an engine (such as cylinder(s), cylinder head(s), coolant passages, intake and exhaust passages, and crankcase) are conceptually distinct, and these items can all be made as discrete pieces that are bolted together. Such construction was very widespread in the early decades of the commercialization of internal combustion engines (1880s to 1920s), and it is still sometimes used in certain applications where it remains advantageous (especially very large engines, but also some small engines). However, it is no longer the normal way of building most petrol engines and diesel engines, because for any given engine configuration, there are more efficient ways of designing for manufacture (and also for maintenance and repair). These generally involve integrating multiple machine elements into one discrete part, and doing the making (such as casting, stamping, and machining) for multiple elements in one setup with one machine coordinate system (of a machine tool or other piece of manufacturing machinery). This yields lower unit cost of production (and/or maintenance and repair). Today most engines for cars, trucks, buses, tractors, and so on are built with fairly highly integrated design, so the words "monobloc" and "en bloc" are seldom used in describing them; such construction is often implicit. Thus "engine block", "cylinder block", or simply "block" are the terms likely to be heard in the garage or on the street.
  • 5.2K
  • 28 Sep 2022
Topic Review
List of Aircraft (D)
This is a list of aircraft in alphabetical order beginning with 'D'.
  • 5.2K
  • 27 Oct 2022
Topic Review
Trailer Connectors in North America
A number of standards prevail in North America, or parts of it, for trailer connectors, the electrical connectors between vehicles and the trailers they tow that provide a means of control for the trailers.
  • 5.2K
  • 28 Oct 2022
Topic Review
Diamond DA40
The Diamond DA40 Star is an Austrian four-seat, single-engine, light aircraft constructed from composite materials. Built in both Austria and Canada, it was developed as a four-seat version of the earlier DA20 by Diamond Aircraft Industries.
  • 5.2K
  • 04 Nov 2022
Topic Review
Yandex Self-Driving Car
Yandex self-driving car (Yandex Self-Driving Group) is a robotaxi project of the Russian-based internet corporation Yandex. The first driverless prototype launched in May 2017. As of 2018, functional service was launched in Russia with prototypes also being tested in Israel and the US. In 2019, Yandex revealed autonomous delivery robots based on the same technology stack as the company's self-driving cars. Since 2020, autonomous robots have been delivering food, groceries and parcels in Russia and the USA. In 2020, the self-driving project was spun-off into a standalone company under the name of Yandex Self-Driving Group (Yandex SDG).
  • 5.0K
  • 27 Oct 2022
Topic Review
Preconsolidation Pressure
Preconsolidation pressure is the maximum effective vertical overburden stress that a particular soil sample has sustained in the past. This quantity is important in geotechnical engineering, particularly for finding the expected settlement of foundations and embankments. Alternative names for the preconsolidation pressure are preconsolidation stress, pre-compression stress, pre-compaction stress, and preload stress. A soil is called overconsolidated if the current effective stress acting on the soil is less than the historical maximum. The preconsolidation pressure can help determine the largest overburden pressure that can be exerted on a soil without irrecoverable volume change. This type of volume change is important for understanding shrinkage behavior, crack and structure formation and resistance to shearing stresses. Previous stresses and other changes in a soil's history are preserved within the soil's structure. If a soil is loaded beyond this point the soil is unable to sustain the increased load and the structure will break down. This breakdown can cause a number of different things depending on the type of soil and its geologic history. Preconsolidation pressure cannot be measured directly, but can be estimated using a number of different strategies. Samples taken from the field are subjected to a variety of tests, like the constant rate of strain test (CRS) or the incremental loading test (IL). These tests can be costly due to expensive equipment and the long period of time they require. Each sample must be undisturbed and can only undergo one test with satisfactory results. It is important to execute these tests precisely to ensure an accurate resulting plot. There are various methods for determining the preconsolidation pressure from lab data. The data is usually arranged on a semilog plot of the effective stress (frequently represented as σ'vc) versus the void ratio. This graph is commonly called the e log p curve or the consolidation curve.
  • 5.0K
  • 17 Oct 2022
Topic Review
Jaguar S-Type
The Jaguar S-Type was an executive car that debuted at the 1998 Birmingham Motor Show and was marketed by Jaguar for model years 1999-2008, reviving the nameplate of the company's 1963-68 S-Type as a four-door notchback saloon. The S-Type received a mild facelift for model year 2005. The 2002 S-Type 4.2 Supercharged V8 at the time, was the fastest road production saloon car in the world. The S-Type was discontinued in late 2007 and replaced by the XF.
  • 5.0K
  • 09 Nov 2022
Topic Review
List of German Aircraft Projects, 1939–45
The aircraft in this list include prototype versions of aircraft used by the German Luftwaffe during World War II and unfinished wartime experimental programmes. In the former, development can stretch back to the 1920s and in the latter the project must have started between 1939-1945.
  • 5.0K
  • 14 Oct 2022
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