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Topic Review
De-Icing
De-icing is the process of removing snow, ice or frost from a surface. Anti-icing is understood to be the application of chemicals that not only de-ice but also remain on a surface and continue to delay the reformation of ice for a certain period of time, or prevent adhesion of ice to make mechanical removal easier.
  • 2.1K
  • 31 Oct 2022
Topic Review
Radio Direction Finder
A radio direction finder (RDF) is a device for finding the direction, or bearing, to a radio source. The act of measuring the direction is known as radio direction finding or sometimes simply direction finding (DF). Using two or more measurements from different locations, the location of an unknown transmitter can be determined; alternately, using two or more measurements of known transmitters, the location of a vehicle can be determined. RDF is widely used as a radio navigation system, especially with boats and aircraft. RDF systems can be used with any radio source, although the size of the receiver antennas are a function of the wavelength of the signal; very long wavelengths (low frequencies) require very large antennas, and are generally used only on ground-based systems. These wavelengths are nevertheless very useful for marine navigation as they can travel very long distances and "over the horizon", which is valuable for ships when the line-of-sight may be only a few tens of kilometres. For aircraft, where the horizon at altitude may extend to hundreds of kilometres, higher frequencies can be used, allowing much smaller antennas. An automatic direction finder, often capable of being tuned to commercial AM radio transmitters, is a feature of almost all modern aircraft. For the military, RDF systems are a key component of signals intelligence systems and methodologies. The ability to locate the position of an enemy transmitter has been invaluable since World War I, and it played a key role in World War II's Battle of the Atlantic. It is estimated that the UK's advanced "huff-duff" systems were directly or indirectly responsible for 24% of all U-boats sunk during the war. Modern systems often use phased array antennas to allow rapid beam forming for highly accurate results. These are generally integrated into a wider electronic warfare suite. Several distinct generations of RDF systems have been used over time, following new developments in electronics. Early systems used mechanically rotated antennas that compared signal strengths from different directions, and several electronic versions of the same concept followed. Modern systems use the comparison of phase or doppler techniques which are generally simpler to automate. Modern pseudo-Doppler direction finder systems consist of a number of small antennas fixed to a circular card, with all of the processing performed by software. Early British radar sets were also referred to as RDF, which was a deception tactic. However, the terminology was not inaccurate; the Chain Home systems used separate omnidirectional broadcasters and large RDF receivers to determine the location of the targets.
  • 2.1K
  • 10 Oct 2022
Topic Review
SpaceX Rocket Engines
Since the founding of SpaceX in 2002, the company has developed four families of rocket engines — Merlin, Kestrel, Draco and SuperDraco — and is currently developing another rocket engine: Raptor.
  • 2.1K
  • 17 Oct 2022
Topic Review
Comet Lake
Comet Lake is Intel's codename for its 10th generation Core microprocessors. They are manufactured using Intel's third 14 nm Skylake process refinement, succeeding the Whiskey Lake U-series mobile processor and Coffee Lake desktop processor families. Intel announced low-power mobile Comet Lake-U CPUs on August 21, 2019, H-series mobile CPUs on April 2, 2020, desktop Comet Lake-S CPUs April 30, 2020, and Xeon W-1200 series workstation CPUs on May 13, 2020. Comet Lake processors and Ice Lake 10 nm processors are together branded as the Intel "10th Generation Core" family. Intel officially launched Comet Lake-Refresh CPUs on the same day as 11th Gen Core Rocket Lake launch. The low-power mobile Comet Lake-U Core and Celeron 5205U CPUs were discontinued on July 7, 2021.
  • 2.1K
  • 21 Nov 2022
Topic Review
Types of Faults on Switchgear
Switchgear is generally known as a switching device. It is used for circuit isolation and the protection of power systems from overload and system faults. The definition of switchgear also includes devices that are utilized to regulate, meter, and control power systems. The term refers to switching and interrupting devices, as well as their combinations with control, instrumentation, metering, protective, and regulating devices, as well as the components of devices involved in dealing with interconnections, items, and supporting structures, which are used primarily in the generation, transmitting distribution, and conversion of electrical power.
  • 2.1K
  • 23 Sep 2022
Topic Review
Measuring Grain Loss during Harvest in Paddy Field
A combine harvester has been widely employed for harvesting paddy in Malaysia. However, it is one of the most challenging machines to operate when harvesting grain crops. Improper handling of a combine harvester can lead to a significant amount of grain loss. Any losses during the harvesting process would result in less income for the farmers.
  • 2.1K
  • 28 Mar 2022
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.
  • 2.1K
  • 27 Oct 2022
Topic Review
Permanent Magnet Machines for High-Speed Applications
High-speed electrical machines have been extensively researched in the last few decades for industrial and domestic applications, including compressors, vacuum pumps, turbine generators, machine tools, flywheel energy storages, and so on. Compared with low-speed and moderate-speed conventional electrical machines, high-speed electrical machines offer advantages such as high-power density, small size, and light weight. More importantly, high-speed electrical machines can be directly connected to high-speed loads, and conventional gear boxes are no longer needed, which avoids complex gear box systems, improves system efficiency and reliability, and reduces system vibration, noise, and cost. With the evolution in the field of power electronics converters, the problems of high frequency supplies, required for high-speed operation, is no longer a restriction. The development of high-speed electrical machines is also supported by the development of high-speed bearing systems with high robustness, fewer losses, and longer lifetime.
  • 2.1K
  • 17 Jan 2022
Topic Review
Resonant cavity antennas technology
       Resonant cavity antennas (RCAs) are suitable candidates to achieve high directivity with a low-cost and easy fabrication process. The stable functionality of the RCAs over different frequency bands, as well as, their pattern reconfigurability make them an attractive antenna structure for the next-generation wireless communication systems, i.e., fifth-generation (5G). The variety of designs and analytical techniques regarding the main radiator and partially reflective surface (PRS) configurations allow dramatic progress and advances in the area of RCAs. Adding different functionalities in a single structure by using additional layers is one appealing feature of the RCA structures, which has opened the various fields of studies toward 5G applications. This paper reviews the recent advances on the RCAs along with the analytical methods, and various capabilities that make them suitable to be used in 5G communication systems. 
  • 2.1K
  • 27 Aug 2020
Topic Review
Evaluation of Externalities of Highway Infrastructures
Various externalities caused by highway infrastructures, such as promoting economic development, traffic congestion, and air pollution, are becoming more and more important. Currently, there is no multi-dimensional quantitative evaluation of the externalities of highway infrastructures, hindering the sustainable planning and development of highway infrastructures. A summary of the status of the evaluation of the externalities of highway infrastructures is from four perspectives: social evaluation, economic evaluation, ecological evaluation, and comprehensive evaluation.
  • 2.1K
  • 11 Mar 2022
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