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Topic Review
Wearable Devices for Stroke Prediction
Stroke ranks as one of the top first leading causes of death and disability worldwide, particularly for the most populous countries in Asia, Europe, and North America. The emerging wearable devices intended to monitor the physiological parameters, and the growth of machine learning applied to predict diseases, are promising solutions to prevent stroke and eventually predict stroke risk.
  • 7.7K
  • 30 Sep 2021
Topic Review
Armor-Piercing Shell
An armor-piercing shell, armour-piercing shell in Commonwealth English, AP for short, is a type of ammunition designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships and cause damage to the lightly-armored interior. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions. AP rounds smaller than 20 mm are typically known as "armor-piercing ammunition", and are intended for lightly-armored targets such as body armor, bulletproof glass and light armored vehicles. The AP shell is now seldom used in naval warfare, as modern warships have little or no armor protection. In the anti-tank role, as tank armor improved during World War II newer designs began to use a smaller but dense penetrating body within a larger shell. These lightweight shells were fired at very high muzzle velocity and retained that speed and the associated penetrating power over longer distances. An armor-piercing shell must withstand the shock of punching through armor plating. Shells designed for this purpose have a greatly strengthened body with a specially hardened and shaped nose. One common addition to later shells is the use of a softer ring or cap of metal on the nose known as a penetrating cap. This lowers the initial shock of impact to prevent the rigid shell from shattering, as well as aiding the contact between the target armor and the nose of the penetrator to prevent the shell from bouncing off in glancing shots. Ideally, these caps have a blunt profile, which led to the use of a further thin aerodynamic cap to improve long-range ballistics. AP shells may contain a small explosive charge known as a "bursting charge". Some smaller-caliber AP shells have an inert filling or an incendiary charge in place of the bursting charge. Designs using newer technologies no longer look like the classic artillery shell and have displaced it. Instead the penetrator is a long rod of dense material like tungsten or depleted uranium (DU) that further improves the terminal ballistics. Whether these modern designs are considered to be AP rounds depends on the definition. Accordingly reference sources vary in whether they include or exclude them.
  • 7.6K
  • 02 Nov 2022
Topic Review
List of Devices with LTE Advanced
List of devices with LTE Advanced support. LTE is a standard for wireless communication and LTE Advanced (Cat 6 and above) is a high speed version of LTE, sometimes marketed as LTE+, 4G+, 4GX, 4.5G or 4G LTE Ultra. LTE support varies from country to country, and the speed may vary depending on user location and how fast they're travelling. The list below shows the devices that should support LTE Cat 6 and above.
  • 7.6K
  • 22 Nov 2022
Topic Review
History of Wind Power
Wind power has been used as long as humans have put sails into the wind. For more than two millennia wind-powered machines have ground grain and pumped water. Wind power was widely available and not confined to the banks of fast-flowing streams, or later, requiring sources of fuel. Wind-powered pumps drained the polders of the Netherlands, and in arid regions such as the American mid-west or the Australian outback, wind pumps provided water for livestock and steam engines. With the development of electric power, wind power found new applications in lighting buildings remote from centrally-generated power. Throughout the 20th century parallel paths developed small wind plants suitable for farms or residences, and larger utility-scale wind generators that could be connected to electricity grids for remote use of power. Today wind-powered generators operate in every size range between tiny plants for battery charging at isolated residences, up to near-gigawatt sized offshore wind farms that provide electricity to national electrical networks. By 2014, over 240,000 commercial-sized wind turbines were operating in the world, producing 4% of the world's electricity.
  • 7.6K
  • 02 Oct 2022
Topic Review
Shooting-Brake
Shooting-brake is a car body style which originated in the 1890s as a horse-drawn wagon used to transport shooting parties with their equipment and game. The first automotive shooting brakes were manufactured in the early 1900s in the United Kingdom. The vehicle style became popular in England during the 1920s and 1930s, and was produced by vehicle manufacturers or as conversions by coachbuilders. The term was used in Britain interchangeably with estate car from the 1930s but has not been in general use for many years and has been more or less superseded by the latter term. Since the 1960s, the term has evolved, describing cars combining elements of both station wagon and coupé body styles, with or without reference to the historical usage for shooting parties. During the 1960s and early 1970s, several high-end European manufacturers produced two-door shooting brake versions of their sports cars. Following a hiatus from the mid 1970s until the early 2010s, the shooting-brake body style entered a resurgence.
  • 7.6K
  • 04 Nov 2022
Topic Review
Broadcast Programming
Television scheduling strategies are employed to give programs the best possible chance of attracting and retaining an audience. They are used to deliver programs to audiences when they are most likely to want to watch them and deliver audiences to advertisers in the composition that makes their advertising most likely to be effective. Digitally based broadcast programming mechanisms are known as electronic program guides (EPG). At a micro level, scheduling is the minute planning of the transmission; what to broadcast and when, ensuring an adequate or maximum utilization of airtime.
  • 7.4K
  • 28 Nov 2022
Topic Review
Control Techniques in Photovoltaic Systems
Complex control structures are required for the operation of photovoltaic electrical energy systems. In this paper, a general review of the controllers used for photovoltaic systems is presented. This entry is based on the most recent papers presented in the literature. The control architectures considered are complex hybrid systems that combine classical and modern techniques, such as artificial intelligence and statistical models. The main contribution of this paper is the synthesis of a generalized control structure and the identification of the latest trends. The main findings are summarized in the development of increasingly robust controllers for operation with improved efficiency, power quality, stability, safety, and economics.
  • 7.4K
  • 19 Feb 2021
Topic Review
Antenna Aperture
In electromagnetics and antenna theory, antenna aperture, effective area, or receiving cross section, is a measure of how effective an antenna is at receiving the power of electromagnetic radiation (such as radio waves). The aperture is defined as the area, oriented perpendicular to the direction of an incoming electromagnetic wave, which would intercept the same amount of power from that wave as is produced by the antenna receiving it. Assume a plane wave in a particular direction has an irradiance or power flux density [math]\displaystyle{ S }[/math]; this is the amount of power passing through a unit area of one square meter. Then if an antenna delivers [math]\displaystyle{ P_o }[/math] watts to the load connected to its output terminals (e.g. the receiver) when irradiated by a uniform field of power density [math]\displaystyle{ S }[/math] watts per square meter, the antenna's aperture for the direction of that plane wave is [math]\displaystyle{ A_e }[/math] in square meters, given by: So the power received by an antenna (in watts) is equal to the power density of the electromagnetic energy (in watts per square meter), multiplied by its aperture (in square meters). Radio waves from a direction where the antenna's aperture is larger thus collect a greater amount of that wave's power; this is more often referred to as antenna gain. To actually obtain that available power [math]\displaystyle{ P_o }[/math], the incoming radiation must be in the state of polarization specified for that antenna, and the load (receiver) must be impedance matched to the antenna's feedpoint impedance. The meaning of aperture is thus based on a receiving antenna, however any receiving antenna can also be used for transmission. Due to reciprocity, an antenna's gain in receiving and transmitting are identical, so the power transmitted by an antenna in different directions (the radiation pattern) is always proportional to the effective area [math]\displaystyle{ A_e }[/math] in each direction; that proportionality factor is derived below. When no direction is specified, [math]\displaystyle{ A_e }[/math] (or "antenna gain") is understood to refer to its maximum value, that is, in the intended direction(s) that the antenna is designed to receive from and/or transmit toward.
  • 7.4K
  • 27 Oct 2022
Topic Review
Parallelism Measurement Methods
At present, the parallelism error was evaluated by contact probe, laser interferometer, and  autocollimator, etc. Moreover, it can also be divided into contact method and non-contact method based on the measurement principle.
  • 7.3K
  • 29 Oct 2020
Topic Review Peer Reviewed
Prefabricated Building Systems—Design and Construction
Modern Methods of Construction with Offsite Manufacturing is an advancement from prefabricated technologies that existed for decades in the construction industry, and is a platform to integrate various disciplines into providing a more holistic solution. Due to the rapid speed of construction, reduced requirement of labour and minimised work on site, offsite manufacturing and prefabricated building systems are becoming more popular, and perhaps a necessity for the future of the global construction industry. The approach to the design and construction of prefab building systems demands a thorough understanding of their unique characteristics.
  • 7.2K
  • 13 Apr 2022
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