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Topic Review
Uniaxial Tensile Test
Tensile testing, also known as tension testing, is a fundamental materials science and engineering test in which a sample is subjected to a controlled tension until failure. Properties that are directly measured via a tensile test are ultimate tensile strength, breaking strength, maximum elongation and reduction in area. From these measurements the following properties can also be determined: Young's modulus, Poisson's ratio, yield strength, and strain-hardening characteristics. Uniaxial tensile testing is the most commonly used for obtaining the mechanical characteristics of isotropic materials. Some materials use biaxial tensile testing. The main difference between these testing machines being how load is applied on the materials.
  • 10.7K
  • 07 Nov 2022
Topic Review
Chalk
Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed of the mineral calcite. Calcite is an ionic salt called calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. Flint (a type of chert) is very common as bands parallel to the bedding or as nodules embedded in chalk. It is probably derived from sponge spicules or other siliceous organisms as water is expelled upwards during compaction. Flint is often deposited around larger fossils such as Echinoidea which may be silicified (i.e. replaced molecule by molecule by flint). Chalk, as seen in Cretaceous deposits of Western Europe, is unusual among sedimentary limestones in the thickness of the beds. Most cliffs of chalk have very few obvious bedding planes unlike most thick sequences of limestone such as the Carboniferous Limestone or the Jurassic oolitic limestones. This may indicate very stable conditions over tens of millions of years. Chalk has greater resistance to weathering and slumping than the clays with which it is usually associated, thus forming tall, steep cliffs where chalk ridges meet the sea. Chalk hills, known as chalk downland, usually form where bands of chalk reach the surface at an angle, so forming a scarp slope. Because chalk is well jointed it can hold a large volume of ground water, providing a natural reservoir that releases water slowly through dry seasons.
  • 10.7K
  • 29 Nov 2022
Topic Review
Digital Protective Relay
In utility and industrial electric power transmission and distribution systems, a digital protective relay is a computer-based system with software-based protection algorithms for the detection of electrical faults. Such relays are also termed as microprocessor type protective relays. They are functional replacements for electro-mechanical protective relays and may include many protection functions in one unit, as well as providing metering, communication, and self-test functions.
  • 10.7K
  • 09 Oct 2022
Topic Review
Antenna Gain
In electromagnetics, an antenna's power gain or simply gain is a key performance number which combines the antenna's directivity and electrical efficiency. In a transmitting antenna, the gain describes how well the antenna converts input power into radio waves headed in a specified direction. In a receiving antenna, the gain describes how well the antenna converts radio waves arriving from a specified direction into electrical power. When no direction is specified, gain is understood to refer to the peak value of the gain, the gain in the direction of the antenna's main lobe. A plot of the gain as a function of direction is called the gain pattern or radiation pattern. Antenna gain is usually defined as the ratio of the power produced by the antenna from a far-field source on the antenna's beam axis to the power produced by a hypothetical lossless isotropic antenna, which is equally sensitive to signals from all directions. Usually this ratio is expressed in decibels, and these units are referred to as decibels-isotropic (dBi). An alternative definition compares the received power to the power received by a lossless half-wave dipole antenna, in which case the units are written as dBd. Since a lossless dipole antenna has a gain of 2.15 dBi, the relation between these units is [math]\displaystyle{ \mathrm{Gain(dBd)} = \mathrm{Gain(dBi)} - 2.15 }[/math]. For a given frequency, the antenna's effective area is proportional to the power gain. An antenna's effective length is proportional to the square root of the antenna's gain for a particular frequency and radiation resistance. Due to reciprocity, the gain of any reciprocal antenna when receiving is equal to its gain when transmitting. Directive gain or directivity is a different measure which does not take an antenna's electrical efficiency into account. This term is sometimes more relevant in the case of a receiving antenna where one is concerned mainly with the ability of an antenna to receive signals from one direction while rejecting interfering signals coming from a different direction.
  • 10.7K
  • 10 Oct 2022
Topic Review
Intel 80486
The Intel 80486, also known as the i486 or 486, is a higher performance follow-up to the Intel 80386 microprocessor. The 80486 was introduced in 1989 and was the first tightly pipelined x86 design as well as the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating-point unit. It represents a fourth generation of binary compatible CPUs since the original 8086 of 1978. A 50 MHz 80486 executes around 40 million instructions per second on average and is able to reach 50 MIPS peak performance. Approximately twice as fast as the 80386 or 80286 per clock cycle, thanks to its five stage pipeline with all stages bound to a single cycle. The on chip enhanced FPU unit was also significantly faster than the 80387 per cycle.
  • 10.7K
  • 03 Nov 2022
Topic Review
Scandinavian Folklore
Scandinavian folklore or Nordic folklore is the folklore of Norway , Sweden, Denmark , Iceland and the Faroe Islands. It has common roots with, and has been mutually influenced by, folklore in England, Germany, the Baltic countries, Finland and Sapmi. Folklore is a concept encompassing expressive traditions of a particular culture or group. The peoples of Scandinavia are heterogenous, as are the oral genres and material culture that has been common in their lands. However, there are some commonalities across Scandinavian folkloric traditions, among them a common ground in elements from Norse mythology as well as Christian conceptions of the world. Among the many tales common in Scandinavian oral traditions, some have become known beyond Scandinavian borders - examples include The Three Billy Goats Gruff and The Giant Who Had No Heart in His Body.
  • 10.7K
  • 19 Oct 2022
Topic Review
Probability Sampling and Non Probability Sampling
There are two types of sampling methods namely: probability sampling and non-probability sampling. Each of these methods includes different types of techniques of sampling. Non-probability Sampling includes Quota sampling, Snowball sampling, Judgment sampling, and Convenience sampling, furthermore,  Probability Sampling includes Simple random, Stratified random, Cluster sampling, Systematic sampling and Multi stage sampling. 
  • 10.7K
  • 18 Feb 2022
Topic Review
Comrade
The term "comrade" generally means 'mate', 'colleague', or 'ally', and derives from the Spanish and Portuguese, term camarada, literally meaning 'chamber mate', from Latin camera, meaning 'chamber' or 'room'. It may also specifically mean "fellow soldier". Political use of the term was inspired by the French Revolution , after which it grew into a form of address between socialists and workers. Since the Russian Revolution, popular culture in the Western world has often associated it with communism.
  • 10.7K
  • 14 Oct 2022
Topic Review
Libertarian Marxism
Libertarian Marxism is a broad scope of economic and political philosophies that emphasize the anti-authoritarian and libertarian aspects of Marxism. Early currents of libertarian Marxism such as left communism emerged in opposition to Marxism–Leninism. Libertarian Marxism is often critical of reformist positions such as those held by social democrats. Libertarian Marxist currents often draw from Karl Marx and Friedrich Engels' later works, specifically the Grundrisse and The Civil War in France; emphasizing the Marxist belief in the ability of the working class to forge its own destiny without the need for a vanguard party to mediate or aid its liberation. Along with anarchism, libertarian Marxism is one of the main currents of libertarian socialism. Libertarian Marxism includes currents such as autonomism, council communism, De Leonism, Lettrism, parts of the New Left, Situationism, Socialisme ou Barbarie and workerism. Libertarian Marxism has often had a strong influence on both post-left and social anarchists. Notable theorists of libertarian Marxism have included Maurice Brinton, Cornelius Castoriadis, Guy Debord, Raya Dunayevskaya, Daniel Guérin, C. L. R. James, Rosa Luxemburg, Antonio Negri, Anton Pannekoek, Fredy Perlman, Ernesto Screpanti, E. P. Thompson, Raoul Vaneigem and Yanis Varoufakis, who claims that Marx himself was a libertarian Marxist.
  • 10.7K
  • 11 Nov 2022
Topic Review
The Transition to Adulthood
The transition to adulthood is a process that brings childhood to an end and turns the individual into a young adult. This process is characterised by the acquisition of new roles for young people, roles linked to the development of personal autonomy that culminate in their emotional and functional independence.
  • 10.7K
  • 31 Aug 2021
Topic Review
Coffee By-Products
The coffee plant Coffea spp. offers much more than the well-known drink made from the roasted coffee bean. During its cultivation and production, a wide variety of by-products are accrued, most of which are currently unused, thermally recycled, or used as animal feed.
  • 10.7K
  • 02 Nov 2020
Topic Review
Olefins Production via Steam Cracking:Effect of Operating Parameters
Various parameters need to be considered to optimize a pyrolysis reactor for the production of ethylene and propylene. These parameters are included temperature, residence time, steam-to-hydrocarbon ratio, and feedstock composition. A higher reaction temperature results in a higher yield of ethylene, a shorter residence time, and higher reaction velocities. A low operating pressure is preferred for this process because of the gas phase reaction inside the reactor tubes and the production of more gaseous molecules for its reactions to the right. The reactor pressure must be kept as low as possible (between 170 and 250 kPa). The gas pressure in the reactor tube outlet is indirectly adjusted by the suction process gas pressure of the compressor in the compression section, downstream of the process. As mentioned earlier, to reach lower hydrocarbon pressures, process steam is co-fed with the hydrocarbon feed to reduce the hydrocarbon partial pressure and lower coke deposition. The addition of steam decreases the partial pressure of the hydrocarbon feed and favors the formation of primary products.
  • 10.7K
  • 16 Dec 2021
Topic Review
Vitamin D Synthesis and Metabolism
Vitamin D, conventionally considered a nutrient, is a potent hormone regulating many physiological functions. Vitamin D exists as a prohormone that needs to be transformed into biologically active products that bind to their cognate nuclear receptors to regulate diverse physiological processes.
  • 10.7K
  • 13 Apr 2022
Topic Review
Luffa Natural Fiber Composites
Natural fiber composites (NFCs) are an evolving area in polymer sciences. Fibers extracted from natural sources hold a wide set of advantages such as negligible cost, significant mechanical characteristics, low density, high strength-to-weight ratio, environmental friendliness, recyclability, etc. Luffa cylindrica, also termed luffa gourd or luffa sponge, is a natural fiber that has a solid potential to replace synthetic fibers in composite materials in diverse applications like vibration isolation, sound absorption, packaging, etc. Recently, many researches have involved luffa fibers as a reinforcement in the development of NFC, aiming to investigate their performance in selected matrices as well as the behavior of the end NFC.
  • 10.6K
  • 25 Sep 2020
Topic Review
Brilliant Blue FCF
Brilliant Blue FCF (Blue 1) is a synthetic organic compound used primarily as a blue colorant for processed foods, medications, dietary supplements, and cosmetics. It is classified as a triarylmethane dye and is known under various names, such as FD&C Blue No. 1 or Acid Blue 9. It is denoted by E number E133 and has a color index of 42090. It has the appearance of a blue powder and is soluble in water and glycerol, with a maximum absorption at about 628 nanometers. It is one of the oldest FDA-approved color additives and is generally considered nontoxic and safe.
  • 10.6K
  • 17 Nov 2022
Biography
Eugen Goldstein
Eugen Goldstein (5 September 1850 – 25 December 1930) was a German physicist. He was an early investigator of discharge tubes, the discoverer of anode rays or canal rays, later identified as positive ions in the gas phase including the hydrogen ion or proton.[1] He was the great uncle of the violinists Mikhail Goldstein and Boris Goldstein. Goldstein was born in 1850 at Gleiwitz Upper Siles
  • 10.6K
  • 30 Dec 2022
Topic Review
Smart Textile Materials
In the last three decades, the development of new kinds of textiles, so-called smart and interactive textiles, has continued unabated. Smart textile materials and their applications are set to drastically boom as the demand for these textiles have been increasing with the emergence of new fibers, new fabrics, and innovative processing technologies. Moreover, people are eagerly demanding washable, flexible, lightweight, and robust e-textiles. These features depend on the properties of the starting material, the post-treatment, and the integration techniques. In this work, a comprehensive review has been conducted on the integration techniques of conductive materials in and onto a textile structure. The review showed that an e-textile can be developed by applying a conductive component on the surface of a textile substrate via plating, printing, coating, and other surface techniques, or by producing a textile substrate from metals and inherently conductive polymers via the creation of fibers and construction of yarns and fabrics with these. In addition, conductive filament fibers or yarns can be also integrated into conventional textile substrates during the fabrication like braiding, weaving, and knitting or as a post-fabrication of the textile fabric via embroidering. Additionally, layer-by-layer 3D printing of the entire smart textile components is possible, and the concept of 4D could play a significant role in advancing the status of smart textiles to a new level.
  • 10.6K
  • 29 Sep 2021
Biography
E. Michael Jones
Eugene Michael Jones (born May 4, 1948) is an American writer, former professor, media commentator and the current editor of Culture Wars magazine (formerly Fidelity Magazine). Jones is known for his writings from a perspective which defends the Catholic Church in American society and overviews the decline of the Catholic communities which were assimilated into the secular American mainstream af
  • 10.6K
  • 29 Dec 2022
Topic Review
Shenyang J-31
The Shenyang J-31 (or "FC-31 fifth Generation Multi-Purpose light Fighter") also known as the "Gyrfalcon" (鹘鹰), or "Falcon Hawk" by some military enthusiasts, is a twin-engine, mid-size fifth-generation jet fighter currently under development by Shenyang Aircraft Corporation. The fighter has also been referred to as the "F-60" or "J-21 Snowy Owl" (雪鸮) in some media reports. Its official name is Shenyang FC-31; J-xx nomenclatures in the Chinese military are reserved to programs launched and financed by the army, while this plane was developed by a state-owned company.
  • 10.6K
  • 10 Nov 2022
Topic Review
SLC35B1 is AXER
To fulfil its role in protein biogenesis, the endoplasmic reticulum (ER) depends on the Hsp70 chaperone BiP that requires a constant ATP-supply. While the original biochemical approaches established hallmarks of the ATP transport into the ER, such as nucleotide selectivity, affinity, and antiport mode, the more recent live-cell imaging methods employing sensitive, localized molecular probes identified the low abundant ATP/ADP exchanger in the membrane of the human ER. Our screen of gene expression datasets for member(s) of the family of solute carriers that are co-expressed with BiP and are ER membrane proteins identified SLC35B1 as a potential candidate. Heterologous expression of SLC35B1 in E. coli revealed that SLC35B1 is highly specific for ATP and ADP and acts in antiport mode, two of four characteristics it shared with the ATP transport activity, which is present in rough ER membranes. Moreover, depletion of SLC35B1 from HeLa cells reduced ER ATP levels and, therefore, BiP activity, which implied that SLC35B1 mediates ATP uptake into the ER plus ADP release from the ER in vivo. Thus, human SLC35B1 provides ATP to the ER and was named ATP/ADP exchanger in the ER membrane or AXER. Furthermore, we characterized a regulatory circuit that is able to maintain the ATP supply in the ER ad hoc and was termed ER low energy response or lowER. Recent work by others confirmed the role and mode of action of AXER and also suggested a possible scenario for long term adjustments (termed CaATiER). Most recently, the structure of AXER was solved and allowed the deduction of its molecular mechanism. Thus, the dust has settled on the discovery of AXER.
  • 10.6K
  • 08 Sep 2025
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