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HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Fault (Power Engineering)
In an electric power system, a fault or fault current is any abnormal electric current. For example, a short circuit is a fault in which current bypasses the normal load. An open-circuit fault occurs if a circuit is interrupted by some failure. In three-phase systems, a fault may involve one or more phases and ground, or may occur only between phases. In a "ground fault" or "earth fault", current flows into the earth. The prospective short-circuit current of a predictable fault can be calculated for most situations. In power systems, protective devices can detect fault conditions and operate circuit breakers and other devices to limit the loss of service due to a failure. In a polyphase system, a fault may affect all phases equally which is a "symmetrical fault". If only some phases are affected, the resulting "asymmetrical fault" becomes more complicated to analyse. The analysis of these types of faults is often simplified by using methods such as symmetrical components. The design of systems to detect and interrupt power system faults is the main objective of power-system protection.
  • 1.5K
  • 20 Oct 2022
Topic Review
Solar Storm of 1859
The solar storm of 1859 (also known as the Carrington Event) was a powerful geomagnetic storm during solar cycle 10 (1855–1867). A solar coronal mass ejection (CME) hit Earth's magnetosphere and induced the largest geomagnetic storm on record, September 1–2, 1859. The associated "white light flare" in the solar photosphere was observed and recorded by British astronomers Richard C. Carrington (1826–1875) and Richard Hodgson (1804–1872). The storm caused strong auroral displays and wrought havoc with telegraph systems. The now-standard unique IAU identifier for this flare is SOL1859-09-01. A solar storm of this magnitude occurring today would cause widespread electrical disruptions, blackouts and damage due to extended outages of the electrical grid. The solar storm of 2012 was of similar magnitude, but it passed Earth's orbit without striking the planet, missing by nine days.
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  • 20 Oct 2022
Topic Review
Sona Language (Artificial)
Sona is an international auxiliary language created by Kenneth Searight and described in a book he published in 1935. The word Sona in the language itself means "auxiliary neutral thing", but the name was also chosen to echo "sonority" or "sound". Searight created Sona as a response to the Eurocentricity of other artificial auxiliary languages of his time, such as Esperanto and Ido. At the same time, Searight intended his language to be more practical than most a priori languages like Solresol or Ro, which were intended to be unbiased by any particular group of natural languages. Thus, Sona sacrificed familiarity of grammar and lexicon for some measure of "universality", while at the same time preserving basic notions common to grammars around the world such as compounding as a method of word formation. Searight used inspiration from many diverse languages, including English, Arabic, Turkish, Chinese and Japanese, to create his eclectic yet regular and logical language. Searight specifically chose only sounds that speakers of many languages could say, therefore making it a true universal. He hoped that in a perfect world, Sona would be taught to young children everywhere. Sona is an agglutinative language with a strong tendency towards being an isolating language. The language has 360 radicals or root words whose meanings are based on the categories in Roget's original thesaurus, plus an additional 15 particles. Ideas and sentences are formed by juxtaposing the radicals. Thus, ra "male" plus ko "child" makes rako "boy". Searight's book, Sona; an auxiliary neutral language (London, K. Paul, Trench, Trubner & Co., Ltd., 1935, LCCN: 35016722) is the only published example of this language. There is a small community on the Internet interested in reviving and using Sona.
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  • 20 Oct 2022
Topic Review
Way of the Five Pecks of Rice
The Way of the Five Pecks of Rice (Chinese: 五斗米道; pinyin: Wǔ Dǒu Mǐ Dào) or the Way of the Celestial Master, commonly abbreviated to simply The Celestial Masters, was a China Taoist movement founded by the first Celestial Master Zhang Daoling in 142 CE. At its height, the movement controlled a theocratic state in the Hanzhong valley, north of Sichuan. In 215 CE, the state was incorporated into Cao Cao's Kingdom of Wei, and the followers of the Celestial Master were dispersed all over China. The Celestial Masters believed that qi pervaded everything, and in order to achieve immortality, the correct balance of qi had to be present within the body. Having a poor quantity of qi in the body, would result in illness, and eventually death. Meditation could be used to restore qi to the body, but sex was to be avoided, as it could result in the loss of qi. If there was the correct balance of qi within the body upon death, an adherent could 'feign death' and be reborn. If not, an adherent would be transported to an earthly prison where he would face eternal torment. The Hanzhong state was divided into 24 regions which were led by an official. Each district had a civil register which recorded people's names and ranks. Three times a year, the registers were updated at the same time as an important feast. While a child's rank rose automatically, adults had to raise their own rank through religious achievement or marriage. Higher ranked people had more divine generals at their command, which could be used to fight demons that caused bad luck or disease. The state had a system of law that encouraged confession and benevolence rather than strict punishment. Criminals were asked to confess their crimes and meditate, and were given public work to do as a sentence. Few texts written by the Hanzhong Celestial Masters survive, with the most important being the Xiang'er commentary to the Dao De Jing. While the Hanzhong state lasted for only twenty-five years, their beliefs influenced all subsequent Daoist movements.
  • 4.1K
  • 25 Oct 2022
Topic Review
Ancient Egyptian Medicine
The medicine of the ancient Egyptians is some of the oldest documented. From the beginnings of the civilization in the late fourth millennium BC until the Persian invasion of 525 BC, Egyptian medical practice went largely unchanged and included simple non-invasive surgery, setting of bones, dentistry, and an extensive set of pharmacopoeia. Egyptian medical thought influenced later traditions, including the Greeks.
  • 8.0K
  • 20 Oct 2022
Topic Review
Doctor of Engineering
The Doctor of Engineering, or Engineering Doctorate, (abbreviated Eng.D., D.Eng., D.Engr., Dr.Eng., or Dr.-Ing.) is a degree awarded on the basis of advanced study and research in engineering and applied sciences. In most countries, it is a terminal research doctorate. A DEng/EngD is equivalent to a PhD in engineering, but different in that it has a solid industrial base and an additional taught element. The DEng/EngD along with the PhD represents the highest academic qualification in engineering, and the successful completion of either in engineering is generally required to gain employment as a full-time, tenure-track university professor or postdoctoral researcher in the field. Individuals can use the academic title doctor, which is often represented via the English honorific "Dr”. DEng/EngD candidates submit a significant project, typically referred to as a thesis or praxis, consisting of a body of original applied research that may be in principle worthy of publication in a peer-reviewed journal. Candidates must defend this work before a panel of expert examiners called a thesis or dissertation committee.
  • 13.2K
  • 20 Oct 2022
Topic Review
Terahertz Spectroscopy and Technology
Terahertz spectroscopy detects and controls properties of matter with electromagnetic fields that are in the frequency range between a few hundred gigahertz and several terahertz (abbreviated as THz). In many-body systems, several of the relevant states have an energy difference that matches with the energy of a THz photon. Therefore, THz spectroscopy provides a particularly powerful method in resolving and controlling individual transitions between different many-body states. By doing this, one gains new insights about many-body quantum kinetics and how that can be utilized in developing new technologies that are optimized up to the elementary quantum level. Different electronic excitations within semiconductors are already widely used in lasers, electronic components and computers. At the same time, they constitute an interesting many-body system whose quantum properties can be modified, e.g., via a nanostructure design. Consequently, THz spectroscopy on semiconductors is relevant in revealing both new technological potentials of nanostructures as well as in exploring the fundamental properties of many-body systems in a controlled fashion.
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  • 25 Oct 2022
Topic Review
Ruby Pistol
The self-loading Ruby pistol is best known as a French World War I sidearm, the Pistolet Automatique de 7 millim.65 genre "Ruby". A very international piece of weaponry, it was closely modeled after John Browning's M1903 design produced by the Belgian Fabrique Nationale de Herstal, and was produced by over 50 Spanish companies, but primarily by the Spanish Gabilondo y Urresti firm (the official "Gabilondo Ruby"). It was decommissioned in 1958, more than a decade after World War II was brought to an end, and was subsequently replaced.
  • 2.9K
  • 20 Oct 2022
Topic Review
Plastic Surgery
Plastic surgery is a surgical specialty involving the restoration, reconstruction, or alteration of the human body. It can be divided into two main categories: reconstructive surgery and cosmetic surgery. Reconstructive surgery includes craniofacial surgery, hand surgery, microsurgery, and the treatment of burns. While reconstructive surgery aims to reconstruct a part of the body or improve its functioning, cosmetic (or aesthetic) surgery aims at improving the appearance of it. Both of these techniques are used throughout the world.
  • 2.1K
  • 20 Oct 2022
Topic Review
Intellectual Disability
Intellectual disability (ID), also known as general learning disability and formerly mental retardation (MR), is a generalized neurodevelopmental disorder characterized by significantly impaired intellectual and adaptive functioning. It is defined by an IQ under 70, in addition to deficits in two or more adaptive behaviors that affect everyday, general living. Intellectual functions are defined under DSM-V as reasoning, problem‑solving, planning, abstract thinking, judgment, academic learning, and learning from instruction and experience, and practical understanding confirmed by both clinical assessment and standardized tests. Adaptive behavior is defined in terms of conceptual, social, and practical skills involving tasks performed by people in their everyday lives. Once focused almost entirely on cognition, the definition now includes both a component relating to mental functioning and one relating to an individual's functional skills in their daily environment. As a result of this focus on the person's abilities in practice, a person with an unusually low IQ may still not be considered to have an intellectual disability. Intellectual disability is subdivided into syndromic intellectual disability, in which intellectual deficits associated with other medical and behavioral signs and symptoms are present, and non-syndromic intellectual disability, in which intellectual deficits appear without other abnormalities. Down syndrome and fragile X syndrome are examples of syndromic intellectual disabilities. Intellectual disability affects about 2 to 3% of the general population. Seventy-five to ninety percent of the affected people have mild intellectual disability. Non-syndromic, or idiopathic cases account for 30 to 50% of these cases. About a quarter of cases are caused by a genetic disorder, and about 5% of cases are inherited from a person's parents. Cases of unknown cause affect about 95 million people (As of 2013).
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  • 20 Oct 2022
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