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Topic Review
Induction Heater
An induction heater is a key piece of equipment used in all forms of induction heating. Typically an induction heater operates at either medium frequency (MF) or radio frequency (RF) ranges. Four main component systems form the basis of a modern induction heater
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  • 28 Nov 2022
Topic Review
Cracking of Wireless Networks
Cracking a wireless network is defeating the security of a wireless local-area network (back-jack wireless LAN). A commonly used wireless LAN is a Wi-Fi network. Wireless LANs have inherent security weaknesses from which wired networks are exempt. Wireless cracking is an information network attack similar to a direct intrusion. Two frequent types of vulnerabilities in wireless LANs are those caused by poor configuration, and those caused by weak or flawed security protocols.
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Topic Review
Gas Dynamic Cold Spray
TIF Cold Spray (CS) (formerly gas dynamic cold spray) is a coating deposition method. Solid powders (1 to 50 micrometers in diameter) are accelerated in a supersonic gas jet to velocities up to 500–1000 m/s. During impact with the substrate, particles undergo plastic deformation and adhere to the surface. To achieve a uniform thickness the spraying nozzle is scanned along the substrate. Metals, polymers, ceramics, composite materials and nanocrystalline powders can be deposited using cold spraying. The kinetic energy of the particles, supplied by the expansion of the gas, is converted to plastic deformation energy during bonding. Unlike thermal spraying techniques, e.g., plasma spraying, arc spraying, flame spraying, or high velocity oxygen fuel (HVOF), the powders are not melted during the spraying process.
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Topic Review
Semaphore Telegraph
A semaphore telegraph is an early system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth centuries. Lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5–20 miles (8.0–32.2 km). Operators at each tower would watch the neighboring tower through a spyglass, and when the semaphore arms began to move spelling out a message, they would pass the message on to the next tower. This system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph, which would replace them half a century later, and would also be cheaper, faster, and more private. The line-of-sight distance between relay stations was limited by geography and weather, and prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station. Modern derivatives of the semaphore system include flag semaphore (a flag relay system) and the heliograph (optical telegraphy using mirror-directed sunlight reflections).
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Biography
Berry L. Cannon
Berry Louis Cannon (March 22, 1935 – February 17, 1969)[1][2][3] was an United States of America aquanaut who served on the SEALAB II and III projects of the U.S. Navy. Cannon died of carbon dioxide poisoning while attempting to repair SEALAB III. It was later found that his diving rig's baralyme canister, which should have absorbed the carbon dioxide Cannon exhaled, was empty.[4] Born Marc
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Topic Review
Tom-Tom Drum
A tom drum is a cylindrical drum with no snares, named from the Anglo-Indian and Sinhala language. It was added to the drum kit in the early part of the 20th century. Most toms range in size between 6 and 20 inches (15 and 51 cm) in diameter, though floor toms can go as large as 24 inches (61 cm). It is not to be confused with a tam-tam, a gong. The Tom is popular and used by players worldwide.
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Topic Review
Plug-in Electric Vehicles in France
The adoption of plug-in electric vehicles in the France is actively supported by the French government through a bonus-malus system through which provides subsidies towards the purchase of all-electric vehicles and plug-in hybrids with low CO2 emissions. The government also provides non-monetary incentives; subsidies for the deployment of charging infrastructure; and long term regulations with specific targets. Additionally, France passed a law in December 2019 to phase out sales of cars that burn fossil fuels by 2040. (As of September 2021), there were 687,876 light-duty plug-in electric vehicles in use in France, consisting of 453,143 all-electric passenger cars and commercial vans, and 234,733 plug-in hybrids. Of these, over 50,000 were fully electric light commercial vehicles. The split among type of powertrain is influenced by the rules of the government subsidies, which favors pure electric vehicles over plug-in hybrids. The plug-in passenger car segment attained a market share of 0.5% in 2013, rose to 1.2% in 2015, 2.2% in 2018, and climbed to 2.8% in 2019. Despite the global strong decline in car sales brought by the COVID-19 pandemic, plug-in electric car sales in France during the first six months of 2020 achieved a record sales volume of 65,267 units, and a market share of 9.1%. (As of December 2019), France listed as the world's second largest market after China for light-duty electric commercial vehicles, with a stock of 49,340 utility vans in circulation. The market share of all-electric utility vans attained 1.2% of new vans registered in 2014, rose to 1.8% in 2018, but declined to 1.7% in 2019. The Renault Zoe has led all-electric car sales in France since 2013, and is the country's all-time best selling plug-in electric car with more than 100,000 units registered through June 2020. The electric utility van segment has been led by the Renault Kangoo Z.E. with over 21,000 units sold through February 2019.
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Topic Review
Windows Phone 8
Windows Phone 8 is the second generation of the Windows Phone mobile operating system from Microsoft. It was released on October 29, 2012, and, like its predecessor, it features a flat user interface based on the Metro design language. It was succeeded by Windows Phone 8.1, which was unveiled on April 2, 2014. Windows Phone 8 replaces the Windows CE-based architecture used in Windows Phone 7 with the Windows NT kernel found in Windows 8. Windows Phone 7 devices cannot run or update to Windows Phone 8, and new applications compiled specifically for Windows Phone 8 are not made available for Windows Phone 7 devices. Developers can make their apps available on both Windows Phone 7 and Windows Phone 8 devices by targeting both platforms via the proper SDKs in Visual Studio. Windows Phone 8 devices are manufactured by Microsoft Mobile (formerly Nokia), HTC, Samsung and Huawei.
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Topic Review
GeForce 2 Series
The GeForce 2 series (NV15) is the second generation of Nvidia's GeForce graphics processing units (GPUs). Introduced in 2000, it is the successor to the GeForce 256. The GeForce 2 family comprised a number of models: GeForce 2 GTS, GeForce 2 Pro, GeForce 2 Ultra, GeForce 2 Ti, GeForce 2 Go and the GeForce 2 MX series. In addition, the GeForce 2 architecture is used for the Quadro series on the Quadro 2 Pro, 2 MXR, and 2 EX cards with special drivers meant to accelerate computer-aided design applications.
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Topic Review
Side Lobe
In antenna engineering, side lobes or sidelobes are the lobes (local maxima) of the far field radiation pattern of an antenna or other radiation source, that are not the main lobe. The radiation pattern of most antennas shows a pattern of "lobes" at various angles, directions where the radiated signal strength reaches a maximum, separated by "nulls", angles at which the radiated signal strength falls to zero. This can be viewed as the diffraction pattern of the antenna. In a directional antenna in which the objective is to emit the radio waves in one direction, the lobe in that direction is designed to have a larger field strength than the others; this is the "main lobe". The other lobes are called "side lobes", and usually represent unwanted radiation in undesired directions. The side lobe directly behind the main lobe is called the back lobe. The longer the antenna relative to the radio wavelength, the more lobes its radiation pattern has. In transmitting antennas, excessive side lobe radiation wastes energy and may cause interference to other equipment. Another disadvantage is that confidential information may be picked up by unintended receivers. In receiving antennas, side lobes may pick up interfering signals, and increase the noise level in the receiver. The power density in the side lobes is generally much less than that in the main beam. It is generally desirable to minimize the sidelobe level (SLL), which is measured in decibels relative to the peak of the main beam. The main lobe and side lobes occur for both transmitting and receiving. The concepts of main and side lobes, radiation pattern, aperture shapes, and aperture weighting, apply to optics (another branch of electromagnetics) and in acoustics fields such as loudspeaker and sonar design, as well as antenna design. Because an antenna's far field radiation pattern is a Fourier Transform of its aperture distribution, most antennas will generally have sidelobes, unless the aperture distribution is a Gaussian, or if the antenna is so small as to have no sidelobes in the visible space. Larger antennas have narrower main beams, as well as narrower sidelobes. Hence, larger antennas have more sidelobes in the visible space (as the antenna size is increased, sidelobes move from the evanescent space to the visible space).
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