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Topic Review
Waveguide (Electromagnetism)
In electromagnetics and communications engineering, the term waveguide may refer to any linear structure that conveys electromagnetic waves between its endpoints. However, the original and most common meaning is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission line mostly at microwave frequencies, for such purposes as connecting microwave transmitters and receivers to their antennas, in equipment such as microwave ovens, radar sets, satellite communications, and microwave radio links. A dielectric waveguide employs a solid dielectric rod rather than a hollow pipe. An optical fibre is a dielectric guide designed to work at optical frequencies. Transmission lines such as microstrip, coplanar waveguide, stripline or coaxial cable may also be considered to be waveguides. The electromagnetic waves in a (metal-pipe) waveguide may be imagined as travelling down the guide in a zig-zag path, being repeatedly reflected between opposite walls of the guide. For the particular case of rectangular waveguide, it is possible to base an exact analysis on this view. Propagation in a dielectric waveguide may be viewed in the same way, with the waves confined to the dielectric by total internal reflection at its surface. Some structures, such as non-radiative dielectric waveguides and the Goubau line, use both metal walls and dielectric surfaces to confine the wave.
  • 2.8K
  • 07 Oct 2022
Topic Review
Psychoanalysis
Psychoanalysis (from Greek: Ancient Greek: + Ancient Greek:) is a set of theories and therapeutic techniques that deal in part with the unconscious mind, and which together form a method of treatment for mental disorders. The discipline was established in the early 1890s by Austrian neurologist Sigmund Freud, who retained the term psychoanalysis for his own school of thought. Freud's work stems partly from the clinical work of Josef Breuer and others. Psychoanalysis was later developed in different directions, mostly by students of Freud, such as Alfred Adler and his collaborator, Carl Gustav Jung, as well as by neo-Freudian thinkers, such as Erich Fromm, Karen Horney, and Harry Stack Sullivan. Psychoanalysis is a controversial discipline, and its effectiveness as a treatment has been contested. It has been largely replaced by the similar but broader psychodynamic psychotherapy in the mid-20th century. although it retains a salient influence within psychiatry. Psychoanalytic concepts are also widely used outside the therapeutic arena, in areas such as psychoanalytic literary criticism, as well as in the analysis of film, fairy tales, philosophical perspectives as Freudo-Marxism and other cultural phenomena.
  • 2.8K
  • 09 Nov 2022
Topic Review
Machine Learning Applications in Failure Predictions
Machine Learning (ML) is a subclass of artificial intelligence (AI) that can be defined as a semi-automated system in which computers create an algorithm by learning from observed data. Machine learning algorithms create a model based on training data and use it to make predictions or judgments without having to be explicitly programmed to do so. In recent years, decision makers and the scientific community have paid close attention to the use of machine learning in risk and reliability assessment. Currently, quite a good amount of work is being carried out in mine equipment failure and reliability assessments and predictive maintenance analysis. A machine learning approach can be used for predicting failures and also to identify important parameters that predict failures.
  • 2.8K
  • 09 Sep 2022
Topic Review
Plain Meaning Rule
The plain meaning rule, also known as the literal rule, is one of three rules of statutory construction traditionally applied by English courts. The other two are the "mischief rule" and the "golden rule". The plain meaning rule dictates that statutes are to be interpreted using the ordinary meaning of the language of the statute. In other words, a statute is to be read word for word and is to be interpreted according to the ordinary meaning of the language, unless a statute explicitly defines some of its terms otherwise or unless the result would be cruel or absurd. Ordinary words are given their ordinary meaning, technical terms are given their technical meaning, and local, cultural terms are recognized as applicable. The plain meaning rule is the mechanism that prevents courts from taking sides in legislative or political issues. Additionally, it is the mechanism that underlies textualism and, to a certain extent, originalism.
  • 2.8K
  • 30 Oct 2022
Topic Review
Pathophysiology of Osteoporosis
Osteoporosis refers to excessive bone loss as reflected by the deterioration of bone mass and microarchitecture, which compromises bone strength. It is a complex multifactorial endocrine disease. Its pathogenesis relies on the presence of several endogenous and exogenous risk factors, which skew the physiological bone remodelling to a more catabolic process that results in net bone loss.
  • 2.8K
  • 15 Nov 2022
Topic Review
Ordnance QF 6-pounder
The Ordnance Quick-Firing 6-pounder 7 cwt,[note 1] or just 6-pounder, was a British 57 mm gun, serving during the Second World War as a primary anti-tank gun of both the British and United States Army (as the 57 mm Gun M1). It was also used as the main armament for a number of armoured fighting vehicles. Although designed before the start of the war, it did not reach service until the North African Campaign in April 1942. There, it replaced the 2-pounder as an anti-tank gun, allowing the 25-pounder gun-howitzer to revert to its intended artillery role.
  • 2.8K
  • 03 Nov 2022
Topic Review
Insulated Cross-Arm Technology
High-voltage transmission technology has advanced quickly with the overall development and increased use of renewable energy. More demands on the insulating system are made when high-voltage power systems evolve. One of the significant factors is the sharp rise in population density, which led to the high demand for electricity. Right-of-way infringement is a problem that frequently occurs these days. Transmission is done over a rated capacity; as a result, the transmission line heats up, the insulation ages, and the electric field becomes distorted. The insulating system is prone to fail too soon when the operating voltage inverses or when there is a significant temperature differential.
  • 2.8K
  • 18 Nov 2022
Topic Review
35 Mm Film
35 mm film (millimeter) is the film gauge most commonly used for motion pictures and chemical still photography (see 135 film). The name of the gauge refers to the width of the photographic film, which consists of strips 34.98 ±0.03 mm (1.377 ±0.001 inches) wide. The standard negative pulldown for movies ("single-frame" format) is four perforations per frame along both edges, which results in 16 frames per foot of film. For still photography, the standard frame has eight perforations on each side. A variety of largely proprietary gauges were devised for the numerous camera and projection systems being developed independently in the late 19th century and early 20th century, ranging from 13 to 75 mm (0.51 to 2.95 in), as well as a variety of film feeding systems. This resulted in cameras, projectors, and other equipment having to be calibrated to each gauge. The 35 mm width, originally specified as ​1 3⁄8 inches, was introduced in 1892 by William Dickson and Thomas Edison, using 120 film stock supplied by George Eastman. Film 35 mm wide with four perforations per frame became accepted as the international standard gauge in 1909, and remained by far the dominant film gauge for image origination and projection until the advent of digital photography and cinematography, despite challenges from smaller and larger gauges, because its size allowed for a relatively good trade-off between the cost of the film stock and the quality of the images captured. The gauge has been versatile in application. It has been modified to include sound, redesigned to create a safer film base, formulated to capture color, has accommodated a bevy of widescreen formats, and has incorporated digital sound data into nearly all of its non-frame areas. Eastman Kodak, Fujifilm and Agfa-Gevaert are some companies that offered 35 mm films. Today Kodak is the last remaining manufacturer of motion picture film. The ubiquity of 35 mm movie projectors in commercial movie theaters made 35 mm the only motion picture format that could be played in almost any cinema in the world, until digital projection largely superseded it in the 21st century. It is difficult to compare the quality of film to digital media, but a good estimate would be about 33.6 megapixels (67.2 megapixels DSLR Bayer equivalent) would equal one 35-millimeter high quality color frame of film.
  • 2.8K
  • 18 Oct 2022
Topic Review Video Peer Reviewed
Three Kinds of Butterfly Effects within Lorenz Models
Within Lorenz models, the three major kinds of butterfly effects (BEs) are the sensitive dependence on initial conditions (SDIC), the ability of a tiny perturbation to create an organized circulation at large distances, and the hypothetical role of small-scale processes in contributing to finite predictability, referred to as the first, second, and third kinds of butterfly effects (BE1, BE2, and BE3), respectively. A well-accepted definition of the butterfly effect is the BE1 with SDIC, which was rediscovered by Lorenz in 1963. In fact, the use of the term “butterfly” appeared in a conference presentation by Lorenz in 1972, when Lorenz introduced the BE2 as the metaphorical butterfly effect. In 2014, the so-called “real butterfly effect”, which is based on the features of Lorenz’s study in 1969, was introduced as the BE3. 
  • 2.8K
  • 06 Jul 2022
Topic Review
Epiphany (Feeling)
An epiphany (from the ancient Greek ἐπιφάνεια, epiphanea, "manifestation, striking appearance") is an experience of a sudden and striking realization. Generally the term is used to describe scientific breakthrough, religious or philosophical discoveries, but it can apply in any situation in which an enlightening realization allows a problem or situation to be understood from a new and deeper perspective. Epiphanies are studied by psychologists and other scholars, particularly those attempting to study the process of innovation. Epiphanies are relatively rare occurrences and generally follow a process of significant thought about a problem. Often they are triggered by a new and key piece of information, but importantly, a depth of prior knowledge is required to allow the leap of understanding. Famous epiphanies include Archimedes's discovery of a method to determine the volume of an irregular object ("Eureka!") and Isaac Newton's realization that a falling apple and the orbiting moon are both pulled by the same force.
  • 2.8K
  • 30 Nov 2022
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