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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Electromagnetically Excited Acoustic Noise and Vibration
Electromagnetically excited acoustic noise is audible sound directly produced by materials vibrating under the excitation of electromagnetic forces. Some examples of electromagnetically excited acoustic noise include the hum of transformers, the whine of some rotating electric machines, or the buzz of fluorescent lamps. The hissing of high voltage transmission lines is due to corona discharge, not magnetism. The phenomenon is also called audible magnetic noise, electromagnetic acoustic noise, or electromagnetically-induced acoustic noise, or more rarely, electrical noise, "coil noise", or "coil whine", depending on the application. The term electromagnetic noise is generally avoided as the term is used in the field of electromagnetic compatibility, dealing with radio frequencies. The term electrical noise describes electrical perturbations occurring in electronic circuits, not sound. For the latter use, the terms electromagnetic vibrations or magnetic vibrations, focusing on the structural phenomenon are less ambiguous. Acoustic noise and vibrations due to electromagnetic forces can be seen as the reciprocal of microphonics, which describes how a mechanical vibration or acoustic noise can induce an undesired electrical perturbation.
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  • 28 Oct 2022
Topic Review
The Bruun Rule
The Bruun Rule is a formula for estimating the magnitude of the retreat of the shoreline of a sandy shore in response to changes in sea level. Originally published in 1962 by Per Bruun, the Bruun Rule was the first to give a relationship between sea level rise and shoreline recession. The rule is a simple, two dimensional mass conversion, and remains in common use to estimate shoreline recession in response to sea level rise, despite criticism and modification, and the availability more complex alternate models.
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  • 28 Oct 2022
Topic Review
Mastercard Foundation
Mastercard Foundation is a global foundation established by Mastercard in 2006. Since its creation, the Foundation has partnered with a number of worldwide Non-governmental organizations and core partners aiming to ameliorate financial life, primarily in the Global South. Its objective is to use a $2 billion endowment on Microfinance programs. With these programs, the Foundation's goal is to make global economics more accessible to people around the world. These programs also strive to give youth around the world new educational experiences and access to financial services and programs.
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  • 28 Oct 2022
Topic Review
Macchi C.205
The Macchi C.205 Veltro (Italian: Greyhound) (also known as MC.205, "MC" standing for "Macchi Castoldi") was an Italian World War II fighter aircraft built by the Aeronautica Macchi. Along with the Reggiane Re.2005 and Fiat G.55, the Macchi C.205 was one of the three "Serie 5" Italian fighters built around the powerful Daimler-Benz DB 605 engine. The C.205 was a development of the earlier C.202 Folgore. With a top speed of some 640 km/h (400 mph) and equipped with a pair of 20 mm cannon as well as 12.7 mm Breda machine guns, the Macchi C.205 Veltro was highly respected by Allied and Axis pilots alike. Widely regarded as one of the best Italian aircraft of World War II, it proved to be extremely effective, destroying a large number of Allied bombers. The Macchi C. 205 proved capable of meeting fighters such as the North American P-51D Mustang on equal terms, which encouraged the Luftwaffe to use a number of these aircraft to equip one Gruppe. While the C.205 was able to match the best Allied opponents in speed and manoeuvrability, it was introduced late in the conflict. Due to the limitations of the Italian war economy, only a small production run was delivered before the end of the war. Like the Spitfire, the Veltro was tricky in its construction and slow to build. Italy's highest scoring ace, Adriano Visconti, achieved 11 of his 26 credited victories in the few weeks he was able to fly the Veltro, with the top scoring Sergente Maggiore pilota Luigi Gorrini shooting down 14 enemy aircraft plus six damaged with the C.205.
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  • 28 Oct 2022
Topic Review
List of Intel Itanium Microprocessors
The Itanium from Intel is a high-end server and supercomputer microprocessor.
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  • 28 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.
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  • 28 Oct 2022
Topic Review
Range Extender (Vehicle)
A range extender vehicle is a battery electric vehicle that includes an auxiliary power unit (APU) known as a 'range extender'. The range extender drives an electric generator which charges a battery which supplies the vehicle's electric motor with electricity. This arrangement is known as a series hybrid drivetrain. The most commonly used range extenders are internal combustion engines, but fuel-cells or other engine types can be used. Range extender vehicles are also referred to as extended-range electric vehicles (EREV), range-extended electric vehicles (REEV), and range-extended battery-electric vehicle (BEVx) by the California Air Resources Board (CARB). The key function of the range extender is to increase the vehicle's range. Range autonomy is one of the main barriers for the commercial success of electric vehicles, and extending the vehicle's range when the battery is depleted helps alleviate range anxiety. A range extending vehicle design can also reduce the consumption of the range extending fuel (such as gasoline) by using the primary fuel (such as battery power), while still maintaining the driving range of a single fuel vehicle powered by a range extending fuel such as gasoline. The range extending fuel is generally considered to be less environmentally and economically friendly to use than the primary fuel source, so the vehicle control system gives preference to using the primary fuel if it's available. However, due to range limitations with the primary fuel source, the range extending fuel allows the vehicle to get many of the cost and environmental benefits of the primary fuel, while maintaining the full driving range of the range extending fuel source. For example, in the Chevy Volt, battery power from the electric grid can be cheaper and more environmentally sustainable than burning gasoline (depending on the electric generation source), but due to the trade offs between the range of a pure electric vehicle and its battery size, adding the range extending gasoline is considered by many to be good compromise to give the Chevy Volt a significantly greater driving range. How many benefits are derived from using the primary fuel however depend on how the vehicles are driven. For example, a first generation Chevy Volt will operate 100% on battery power from the electric grid for the first 60 km (37 miles), while the second generation Volt will operate on 100% battery power for the first 85 km (53 miles) when fully recharged between trips. However, if the same Chevy Volt is driven for hundreds of miles a day it will require significant gasoline as the battery will be quickly depleted. Using the gasoline engine to generate power for the motors, the economy ratings are 6.4 L/100 km (37 mpg‑US) and 5.6 L/100 km (42 mpg‑US) for the different generation models. Therefore, it is critical to understand the driving patterns of the average commuter to fully understand the impact these range extending vehicles will have in the real world. Many range extender vehicles, including the Chevrolet Volt and the BMW i3, are able to charge their batteries from the grid as well as from the range extender, and therefore are a type of plug-in hybrid electric vehicle (PHEV). When a range extender uses conventional fuels they can re-fuel at regular fuel stations, which provides them with a similar driving range to conventional automobiles. As an REEV is only propelled by the electric motor it can do away with the weight and cost associated with the gearbox transmission system typically used in internal combustion engine cars. Further, as the range extender does not need to increase or decrease output in line with the power needs of the vehicle (this task is handled by the electric motor) the range extender can be sized to satisfy the vehicle's average power requirement rather than its peak power requirement (such as when accelerating). The range extender can also operate much closer to its most efficient rotational speed. These design features allow an REEV to convert fossil fuel energy to electric power and vehicle motion very efficiently.
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  • 28 Oct 2022
Topic Review
OpenCog
OpenCog is a project that aims to build an open source artificial intelligence framework. OpenCog Prime is an architecture for robot and virtual embodied cognition that defines a set of interacting components designed to give rise to human-equivalent artificial general intelligence (AGI) as an emergent phenomenon of the whole system. OpenCog Prime's design is primarily the work of Ben Goertzel while the OpenCog framework is intended as a generic framework for broad-based AGI research. Research utilizing OpenCog has been published in journals and presented at conferences and workshops including the annual Conference on Artificial General Intelligence. OpenCog is released under the terms of the GNU Affero General Public License. OpenCog is in use by more than 50 companies, including Huawei and Cisco.
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  • 28 Oct 2022
Topic Review
Perturbation
In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massive body. The other forces can include a third (fourth, fifth, etc.) body, resistance, as from an atmosphere, and the off-center attraction of an oblate or otherwise misshapen body.
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  • 28 Oct 2022
Topic Review
Northwestern European People
Northwestern European people are a pan-ethnic group, or multi-ethnic regional grouping, and the inhabitants of Northwestern Europe. Northwest or Northwestern Europeans can usually trace back full or partial heritage to Great Britain and Ireland, Northern Germany, Denmark , Sweden, Norway , the Netherlands, Northern France, Belgium, and other places connected to Northwestern Europe geographically or culturally. As the pan-ethnic group is also a cultural category, rather than exclusively geographical; it often can include peoples with ancestry from bordering regions such as Austria, Finland , Southern Germany, and Switzerland . There is a large Northwestern European diaspora, with significant numbers within North America (Northwestern European Americans and Northwestern European Canadians), and Northwestern European Australians in Oceania. Other subgroupings of Europeans include Eastern European people and Southern European people.
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  • 28 Oct 2022
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