Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort:
Hottest Latest Alphabetical (A-Z) Alphabetical (Z-A)
Type:
All Topic Review Biography
Topic Review
List of Research Stations in the Arctic
A number of governments maintain permanent research stations in the Arctic. Also known as Arctic bases, polar stations or ice stations, these bases are widely distributed across the northern polar region of the earth. Historically few research stations have been permanent. Most of them were temporary, being abandoned after the completion of the project or owing to lack of funding to continue the research. Some of these were military or intelligence stations (listening posts) created as a result of the proximity of the U.S. and Soviet Union to each other's landmass across the polar region. Ice stations are constructed on land or on ice that rests on land, while others are drifting ice stations built on the sea ice of the high latitudes of the Arctic Ocean.
  • 3.6K
  • 30 Nov 2022
Topic Review
Floating Wind Turbines
Globally, the wind resource in deep water (depths > 60 m) is very abundant. Due to the abundance of potential at these depths, the wind turbines will need the design of a floating platform because the wind turbines that are currently in operation are mostly fixed at the bottom and are dependent upon conventional concrete with a gravity base that is not feasible at these depths. A balance among the two varying principles (i.e., the requirement for a stable foundation for the wind turbine’s control and operation and the nature of the substructure being innate, to respond to environmental forces) is required for the design of the floating platform for wind energy. The absence of rigid foundations results in an additional six degrees of freedom (DOFs) for the platform of floating turbines; three translational (surge X, sway Y, and heave Z) and three rotational (roll RotX, pitch RotY, and yaw RotZ). For the platforms of onshore wind turbines and bottom-mounted offshore wind turbines, the effect of soil-structure interaction (SSI) can be modeled with six degrees of freedom; three translational (horizontal forces in X and Y and vertical force in Z) and three rotational (rocking moments in X and Y and a torsional moment in Z) respectively.
  • 3.6K
  • 11 Oct 2021
Topic Review
Cathode Ray Tube
The cathode ray tube (CRT) is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beam(s) onto the screen to create the images. The images may represent electrical waveforms (oscilloscope), pictures (television, computer monitor), radar targets, or other phenomena. CRTs have also been used as memory devices, in which case the visible light emitted from the fluorescent material (if any) is not intended to have significant meaning to a visual observer (though the visible pattern on the tube face may cryptically represent the stored data). In television sets and computer monitors, the entire front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster. An image is produced by controlling the intensity of each of the three electron beams, one for each additive primary color (red, green, and blue) with a video signal as a reference. In all modern CRT monitors and televisions, the beams are bent by magnetic deflection, a varying magnetic field generated by coils and driven by electronic circuits around the neck of the tube, although electrostatic deflection is commonly used in oscilloscopes, a type of electronic test instrument. A CRT is constructed from a glass envelope which is large, deep (i.e., long from front screen face to rear end), fairly heavy, and relatively fragile. The interior of a CRT is evacuated to approximately 0.01 pascals (9.9×10−8 atm) to 133 nanopascals (1.31×10−12 atm), evacuation being necessary to facilitate the free flight of electrons from the gun(s) to the tube's face. The fact that it is evacuated makes handling an intact CRT potentially dangerous due to the risk of breaking the tube and causing a violent implosion that can hurl shards of glass at great velocity. As a matter of safety, the face is typically made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions, particularly if the CRT is used in a consumer product. Since the late 2000s, CRTs have been largely superseded by newer "flat panel" display technologies such as LCD, plasma display, and especially OLED displays, which in the case of LCD and OLED displays have lower manufacturing costs and power consumption, as well as significantly less weight and bulk. Flat panel displays can also be made in very large sizes; whereas 38 to 40 in (97 to 102 cm) was about the largest size of a CRT television, flat panels are available in 60 in (150 cm) and larger sizes.
  • 3.6K
  • 02 Dec 2022
Topic Review
Electronic Trading
Electronic or scripless trading, sometimes called e-trading or paperless trading is a method of trading securities (such as stocks, and bonds), foreign exchange or financial derivatives electronically. Information technology is used to bring together buyers and sellers through an electronic trading platform and network to create virtual market places. They can include various exchange-based systems, such as NASDAQ, NYSE Arca and Globex, as well as other types of trading platforms, such as electronic communication networks (ECNs), alternative trading systems, crossing networks and "dark pools". Electronic trading is rapidly replacing human trading in global securities markets. Electronic trading is in contrast to older floor trading and phone trading and has a number of advantages, but glitches and cancelled trades do still occur.
  • 3.6K
  • 14 Oct 2022
Topic Review
SpaceX Dragon 2
The SpaceX Dragon 2 is a class of reusable spacecraft developed and manufactured by American aerospace manufacturer SpaceX as the successor to the Dragon cargo spacecraft. It has two variants: Crew Dragon, a human-rated capsule capable of ferrying up to seven astronauts, and Cargo Dragon, an updated replacement for the original Dragon spacecraft. The spacecraft launches atop a Falcon 9 Block 5 rocket and returns to Earth via an ocean splashdown. Unlike its predecessor, the spacecraft can dock itself to the ISS instead of being berthed. Crew Dragon is equipped with an integrated launch escape system (LES) capable of accelerating the vehicle away from the rocket in an emergency at 11.8 m/s2, accomplished by using a set of four side-mounted thruster pods with two SuperDraco engines each. The spacecraft features redesigned solar arrays and a modified outer mold line compared to the original Dragon, and possess new flight computers and avionics. As of March 2020, four Dragon 2 spacecraft have been manufactured (not counting structural test articles that were never airborne). Crew Dragon serves as one of two spacecraft that is expected to transport crews to and from the International Space Station (ISS) under NASA's Commercial Crew Program, the other being the Boeing CST-100 Starliner. It is also expected to be used in flights by American space tourism company Space Adventures and to shuttle tourists to and from Axiom Space's planned space station. Crew Dragon's first non-piloted test flight occurred in March 2019, and its first crewed flight – with astronauts Robert Behnken and Douglas Hurley – occurred in May 2020. This test flight marked the first time a private company launched a crewed orbital spacecraft. Cargo Dragon is expected to supply cargo to the ISS under a Commercial Resupply Services-2 contract with NASA, along with Northrop Grumman Innovation Systems' Cygnus spacecraft and Sierra Nevada Corporation's Dream Chaser spacecraft. The first flight of the Cargo Dragon is planned to launch in October 2020.
  • 3.6K
  • 26 Oct 2022
Topic Review
Direct and Indirect Solar Gain Systems
The energy crisis, the risk of interruptions or irregular supplies of conventional energy carriers, and the need to protect the environment stimulate the search for new solutions to improve the heat balance of buildings with the use of solar energy. Based on the criterion of the storage, distribution, and discharge time of stored heat, passive solar gain solutions can be divided into direct and indirect solar gain systems.
  • 3.6K
  • 15 Dec 2022
Topic Review
Scunthorpe Problem
The Scunthorpe problem is the unintentional blocking of websites, e-mails, forum posts or search results by a spam filter or search engine because their text contains a string (or substring) of letters that appear to have an obscene or otherwise unacceptable meaning. Names, abbreviations, and technical terms are most often cited as being affected by the issue. The problem arises since computers can easily identify strings of text within a document, but interpreting words of this kind requires considerable ability to interpret a wide range of contexts, possibly across many cultures, which is an extremely difficult task. As a result, broad blocking rules may result in false positives affecting innocent phrases.
  • 3.6K
  • 14 Oct 2022
Topic Review
Vulgate
The Vulgate (/ˈvʌlɡeɪt, -ɡət/) is a late-4th-century Latin translation of the Bible that became the Catholic Church's officially promulgated Latin version of the Bible during the 16th century. The translation was largely the work of Jerome, who in 382 had been commissioned by Pope Damasus I to revise the Vetus Latina ("Old Latin") Gospels then in use by the Roman Church. Jerome, on his own initiative, extended this work of revision and translation to include most of the books of the Bible, and once published, the new version was widely adopted and eventually eclipsed the Vetus Latina; so that by the 13th century, it had taken over from the former version the appellation of versio vulgata (the "version commonly used") or vulgata for short, and in Greek as βουλγάτα ("Voulgata"). The Catholic Church affirmed the Vulgate as its official Latin Bible at the Council of Trent (1545–63), though there was no authoritative edition at that time. The Clementine edition of the Vulgate of 1592 became the standard Bible text of the Roman Rite of the Roman Catholic Church and remained so until 1979 when the Nova Vulgata was promulgated.
  • 3.6K
  • 24 Nov 2022
Topic Review
Prokaryotic Translation
Prokaryotic translation is the process by which messenger RNA is translated into proteins in prokaryotes.
  • 3.6K
  • 19 Oct 2022
Topic Review
Cousin
Most generally, in the lineal kinship system used in the English-speaking world, a cousin is a type of familial relationship in which two relatives are two or more familial generations away from their most recent common ancestor. Commonly, "cousin" refers to a first cousin – a relative of the same generation whose most recent common ancestor with the subject is a grandparent. Degrees and removals are separate measures used to more precisely describe the relationship between cousins. Degree measures the separation, in generations, from the most recent common ancestor(s) to a parent of one of the cousins (whichever is closest), while removal measures the difference in generations between the cousins themselves, relative to their most recent common ancestor(s). To illustrate usage, a second cousin is a cousin with a degree of two; there are three (not two) generations from the common ancestor(s). When the degree is not specified, first cousin is assumed. A cousin "once removed" is a cousin with one removal. When the removal is not specified, no removal is assumed. Various governmental entities have established systems for legal use that can precisely specify kinship with common ancestors any number of generations in the past; for example, in medicine and in law, a first cousin is a type of third-degree relative.
  • 3.6K
  • 25 Oct 2022
  • Page
  • of
  • 5358
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of Social Sciences
Encyclopedia of COVID-19
Encyclopedia of Fungi
Encyclopedia of Digital Society, Industry 5.0 and Smart City
ScholarVision Creations
Feedback