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Topic Review

Load Frequency Control System

Power systems are complex systems that have great importance to socio-economic development due to the fact that the entire world relies on the electric network power supply for day-to-day life. Therefore, for the stable operation of power systems, several protection and control techniques are necessary. Among various power system controls, the load frequency control (LFC) is the most time-consuming control mechanism of power systems due to the involvement of mechanical parts. As the control algorithms of frequency stabilization deliver control signals in the timescale of seconds, LFC systems cannot handle complicated data validation algorithms, making them more vulnerable to disturbances and cyber-attacks. Hence advanced research is highly encouraged in the field of development of attack resilient frequency stabilization techniques and in the area of cyber-security of LFC systems.

9.1K
26 Oct 2020

Topic Review

Sub Synchronous Oscillation Phenomenon

The definition of sub synchronous oscillation (SSO) according to the IEEE Sub Synchronous Resonance Working Group is as follows. “Sub synchronous oscillation is an electric power system condition where the electric network exchanges significant energy with a turbine generator at one or more of the natural frequencies of the combined system below the synchronous frequency of the system following a disturbance from equilibrium”. According to the classification of SSO by the IEEE Sub Synchronous Resonance Working Group, there are two types of SSO, namely sub synchronous resonance (SSR) and device dependent sub synchronous oscillation (DDSSO). Sub synchronous control interaction (SSCI) and sub synchronous torsional interaction (SSTI) are other types of SSO. However, they are not included in the formal classification.

9.1K
09 Dec 2022

Topic Review

Applications of Heterocyclic Compounds

Fluorescently labelled heterocyclic compounds are useful in bioanalytical applications, including in vivo imaging, high throughput screening, diagnostics, and light-emitting diodes. These compounds have various therapeutic properties, including antifungal, antitumor, antimalarial, anti-inflammatory, and analgesic activities. Different neutral fluorescent markers containing nitrogen heterocycles (quinolones, azafluoranthenes, pyrazoloquinolines, etc.) have several electrochemical, biological, and nonlinear optic applications. Photodynamic therapy (PDT), which destroys tumors and keeps normal tissues safe, works in the presence of molecular oxygen with light and a photosensitizing drugs (dye) to obtain a therapeutic effect.

9.1K
18 Oct 2022

Topic Review

Devil in Christianity

The Devil in Christianity is the personification of evil and author of sin, who rebelled against God in an attempt to become equal to God himself.[lower-alpha 1] He is depicted as a fallen angel, who was expelled from Heaven at the beginning of time, before God created the material world, and is in constant opposition to God. The devil is identified with several figures in the Bible including the serpent in the Garden of Eden, Lucifer, Satan, the tempter of the Gospels, Leviathan, and the dragon in the Book of Revelation. Early scholars discussed the role of the devil. Scholars influenced by neoplatonic cosmology, like Origen and Pseudo-Dionysius, portrayed the devil as representing deficiency and emptiness, the entity most remote from the divine. According to Augustine of Hippo the realm of the devil is not nothingness, but an inferior realm standing in opposition to God. The standard Medieval depiction of the devil was set up by Gregory the Great. He integrated the devil, as the first creation of God, into the Christian angelic hierarchy as the highest of the angels (either a cherub or a seraph). But as high as he stood in heaven, so far he fell into the depths of hell and became the leader of demons. Since the early reformation period, the devil was imagined as an increasingly powerful entity, with not only a lack of goodness but also a conscious will against God, his word, and his creation. Simultaneously, some reformists interpreted the devil as a mere metaphor for human's inclination to sin and so downgraded the importance of the devil. While the devil played for most scholars no significant role in the Modern Era, he became more important in contemporary Christianity again. At various times in history, some people such as the Cathars and the Bogomiles, as well as theologians like Marcion and Valentinus, believed that the devil was involved in creating the world. Today these views are not part of mainstream Christianity.

9.1K
06 Dec 2022

Topic Review

A lingua franca is any language widely used beyond the population of its native speakers. The de facto status of lingua franca is usually "awarded" by the masses to the language of the most influential nation(s) of the time. Any given language normally becomes a lingua franca primarily by being used for international commerce, but can be accepted in other cultural exchanges, especially diplomacy. Occasionally the term "lingua franca" is applied to a fully established formal language; thus formerly it was said that French was the lingua franca of diplomacy. The term "lingua franca" was originally used by Arabs to name all Romance languages, and especially Italian (Arabs used the name 'Franks' for all peoples in Western Europe). Then, it meant a language with a Romance lexicon (most words derived from Latin which then evolved into early forms of Spanish and Italian) and a very simple grammar, that till the end of the 19th century was used by mariners in the Mediterranean Sea, particularly in the Middle East and Northern Africa. A related concept is that of a “vehicular language.” It is defined as a basic linguistic structure for proposed “international auxiliary languages,” for example, the use of an Indo-European language, or Indo-European itself, in the development of Esperanto.

9.1K
20 Oct 2022

Topic Review

Mathematics of Sudoku

The class of Sudoku puzzles consists of a partially completed row-column grid of cells partitioned into N regions each of size N cells, to be filled in ("solved") using a prescribed set of N distinct symbols (typically the numbers {1, ..., N}), so that each row, column and region contains exactly one of each element of the set. The properties of Sudoku puzzles and their solutions can be investigated using mathematics and algorithms.

9.1K
12 Oct 2022

Topic Review

The Toophan (Persian: طوفان‎ "Storm", rarely Toofan) is an Iranian SACLOS anti-tank guided missile reverse-engineered from the United States of America BGM-71 TOW missile. The Toophan 1, an unlicensed copy of the BGM-71A TOW missile, began mass production in 1988 and the Toophan 2, a BGM-71C ITOW variant, was publicly shown in 2000. The Toophan comes in at least 11 variants, many of which are poorly documented, including variants with laser guidance, thermobaric warheads, and tandem-warheads with increased penetration. The Toophan is manufactured jointly by the Aerospace Industries Organization of Iran and Iran Electronics Industries. It's normally deployed from ground-based tripods, and can also be mounted on fighting vehicles and helicopters. Like the BGM-71 TOW missile, the Toophan is a large, rugged, powerful, and reliable anti-tank guided missile deployed by small teams against tanks, armored vehicles, buildings, and other targets. The Toophan forms the backbone of the Iranian Armed Forces's ATGM inventory and is procured in large quantities in a variety of variants. The Toophan has been exported to the governments of Iraq and Syria and to a large number of non-state actors in the Middle East, and has been used in the Iran–Iraq War, the 2006 Lebanon War and the Iraqi, Syrian, and Yemeni Civil Wars.

9.1K
14 Nov 2022

Topic Review

The Effect of Parental Styles on Social Skills

Parental educational styles have a significant effect in personal development. These styles (authoritative, democratic, permissive and neglectful) can be related to affects and social skills at the individual level. The results suggest that parenting styles are closely related to affects and social skills. It is also suggested that affects play a mediating role in the relationship between parenting styles and social skills.

9.1K
23 Mar 2022

Topic Review

Acid throwing, also called an acid attack, a vitriol attack or vitriolage, is a form of violent assault defined as the act of throwing acid or a similarly corrosive substance onto the body of another "with the intention to disfigure, maim, torture, or kill". Perpetrators of these attacks throw corrosive liquids at their victims, usually at their faces, burning them, and damaging skin tissue, often exposing and sometimes dissolving the bones. The most common types of acid used in these attacks are sulfuric and nitric acid. Hydrochloric acid is sometimes used, but is much less damaging. Aqueous solutions of strongly alkaline materials, such as caustic soda (sodium hydroxide), are used as well, particularly in areas where strong acids are controlled substances. The long term consequences of these attacks may include blindness, as well as permanent scarring of the face and body, along with far-reaching social, psychological, and economic difficulties. Today, acid attacks are reported in many parts of the world. Since the 1990s, Bangladesh has been reporting the highest number of attacks and highest incidence rates for women, with 3,512 Bangladeshi people acid attacked between 1999 and 2013, and in Pakistan and India acid attacks are at an all-time high and increasing every year. Although acid attacks occur all over the world, this type of violence is most common in South Asia. The UK has one of the highest rates of acid attacks per capita in the world, according to Acid Survivors Trust International (ASTI). In 2016 there were over 601 acid attacks in the UK based on ASTI figures. Over 1,200 cases were recorded over the past 5 years. From 2011 to 2016 there were 1,464 crimes involving acid or corrosive substance in London alone.

9.1K
21 Oct 2022

Topic Review

CASC Rainbow (Cai Hong, abbreviated as CH) is a series of unmanned aerial vehicles (UAVs) developed by the China Academy of Aerospace Aerodynamics, an entity under the China Aerospace Science and Technology Corporation (CASC). The China Academy of Aerospace Aerodynamics is also known as the 11th Academy of CASC, or 701st Research Institute.

9.1K
17 Oct 2022

Topic Review

Atomic units (au or a.u.) form a system of natural units which is especially convenient for atomic physics calculations. There are two different kinds of atomic units, Hartree atomic units and Rydberg atomic units, which differ in the choice of the unit of mass and charge. This article deals with Hartree atomic units, where the numerical values of the following four fundamental physical constants are all unity by definition: In Hartree units, the speed of light is approximately [math]\displaystyle{ 137 }[/math]. Atomic units are often abbreviated "a.u." or "au", not to be confused with the same abbreviation used also for astronomical units, arbitrary units, and absorbance units in different contexts.

9.1K
10 Nov 2022

Topic Review

Seed Morphology

Seed morphology is the scientific analysis and description of the shape of seeds.

9.1K
28 Oct 2020

Topic Review

Prime Video, also marketed as Amazon Prime Video, is an American Internet video on demand service that is developed, owned, and operated by Amazon. It offers television shows and films for rent or purchase and Prime Video, a selection of Amazon Studios original content and licensed acquisitions included in the Amazon's Prime subscription. In the United Kingdom , United States , Germany , and many other territories, access to Prime Video is also available through a video-only membership, which does not require a full Prime subscription. In France and Italy, and other countries like Australia , Canada , India , etc. Prime Video content is only accessible through a dedicated Prime Video website. In some countries Prime Video additionally offers Amazon Channels, which allows viewers to subscribe to other suppliers' content, including HBO in the United States. Launched on September 7, 2006 as Amazon Unbox in the United States, the service grew with its expanding library, and added the Prime Video membership with the development of Prime. It was then renamed as Amazon Instant Video on Demand. After acquiring the local streaming and DVD-by-mail service LoveFilm in 2011, Prime Video was added to Prime in the United Kingdom, Germany and Austria in 2014, a move that angered some Prime UK members as the bundling was non-negotiable with a 61% increase in subscription fee. In the UK, Germany, and Austria, Prime Video has been available on a monthly subscription of £5.99 or €7.99 per month, continuing the plan of LoveFilm Instant. The service was previously available in Norway , Denmark and Sweden in 2012, but was discontinued in 2013. On April 18, 2016, Amazon split Prime Video from Amazon Prime in the US for $8.99 per month. The service also hosts Amazon Original content alongside titles on Video as well. On December 14, 2016, Prime Video launched worldwide (except for Mainland China, Cuba, Iran, North Korea, Syria) expanding its reach beyond the US, the UK, Germany, Austria, and Japan. Among the new territories, the service was included with Prime in Belgium, Canada , France , India , Italy, Spain , Poland , and Brazil , while for all other countries – for instance Bulgaria – it was made available for a monthly promotional price of $/€2.99 per month for the first six months and $/€5.99 per month thereafter.

9.0K
29 Nov 2022

Topic Review

Remarriage is a marriage that takes place after a previous marital union has ended, as through divorce or widowhood. Some individuals are more likely to remarry than others; the likelihood can differ based on previous relationship status (e.g. divorced vs. widowed), level of interest in establishing a new romantic relationship, gender, race, and age among other factors. Those who choose not to remarry may prefer alternative arrangements like cohabitation or living apart together. Remarriage also provides mental and physical health benefits. However, although remarried individuals tend to have better health than individuals who do not repartner, they still generally have worse health than individuals who have remained continuously married. Someone who repeatedly remarries is referred to as a serial wedder.

9.0K
27 Oct 2022

Topic Review

Religious Studies

Religious studies, alternately known as the study of religion, is an academic field devoted to research into religious beliefs, behaviors, and institutions. It describes, compares, interprets, and explains religion, emphasizing systematic, historically based, and cross-cultural perspectives. While theology attempts to understand the nature of transcendent or supernatural forces (such as deities), religious studies tries to study religious behavior and belief from outside any particular religious viewpoint. Religious studies draws upon multiple disciplines and their methodologies including anthropology, sociology, psychology, philosophy, and history of religion. Religious studies originated in the 19th century, when scholarly and historical analysis of the Bible had flourished, and Hindu and Buddhist texts were first being translated into European languages. Early influential scholars included Friedrich Max Müller, in England, and Cornelius P. Tiele, in the Netherlands. Today religious studies is practiced by scholars worldwide. In its early years, it was known as Comparative Religion or the Science of Religion and, in the USA, there are those who today also know the field as the History of religion (associated with methodological traditions traced to the University of Chicago in general, and in particular Mircea Eliade, from the late 1950s through to the late 1980s). The term "religion" originated from the Latin noun "religio", that was nominalized from one of three verbs: "relegere" (to turn to constantly/observe conscientiously); "religare" (to bind oneself [back]); and "reeligere" (to choose again). Because of these three different potential meanings, an etymological analysis alone does not resolve the ambiguity of defining religion, since each verb points to a different understanding of what religion is. During the Medieval Period, the term "religious" was used as a noun to describe someone who had joined a monastic order (a "religious"). The religious studies scholar Walter Capps described the purpose of the discipline as to provide "training and practice... in directing and conducting inquiry regarding the subject of religion". At the same time, Capps stated that its other purpose was to use "prescribed modes and techniques of inquiry to make the subject of religion intelligible." Religious studies scholar Robert A. Segal characterised the discipline as "a subject matter" that is "open to many approaches", and thus it "does not require either a distinctive method or a distinctive explanation to be worthy of disciplinary status." Different scholars operating in the field have different interests and intentions; some for instance seek to defend religion, while others seek to explain it away, and others wish to use religion as an example with which to prove a theory of their own. Some scholars of religious studies are interested in primarily studying the religion to which they belong. Scholars of religion have argued that a study of the subject is useful for individuals because it will provide them with knowledge that is pertinent in inter-personal and professional contexts within an increasingly globalised world. It has also been argued that studying religion is useful in appreciating and understanding sectarian tensions and religious violence.

9.0K
22 Nov 2022

Topic Review

Fundamental Properties of Hempcrete

A bio-fiber composite made up of hemp hurd or shiv and mineral binder, hempcrete is a form of lime-based construction material. The binder that is made by combining water with these ingredients is expected to completely coat all of the hemp shiv particles after sufficient mixing. A chemical reaction between the lime binder and water hardens the binder, cementing the hurd pieces together. The term “bonded cellulose insulation” could be broadly used to describe this mixture. Hempcrete is what is left after the binder has dried and been allowed to build up strength with time.

9.0K
21 Feb 2024

Topic Review

Methods of Preparation of Quinoxalines

Quinoxaline is a fused heterocycle system of a benzene ring and pyrazine ring. It has earned considerable attention due to its importance in the field of medicinal chemistry. The system is of extensive importance due to its comprehensive array of biological activities. Quinoxaline derivatives have been used as anticancer, anticonvulsant, anti-inflammatory, antidiabetic, antioxidant, antibacterial, anti-TB, antimalarial, antiviral, anti-HIV, and many other uses. Variously substituted quinoxalines are significant therapeutic agents in the pharmaceutical industry.

9.0K
23 Nov 2023

Topic Review

Trickle-Down Economics

Trickle-down economics, also called trickle-down theory, refers to the economic proposition that taxes on businesses and the wealthy in society should be reduced as a means to stimulate business investment in the short term and benefit society at large in the long term. In recent history, the term has been used by critics of supply-side economic policies, such as "Reaganomics". Whereas general supply-side theory favors lowering taxes overall, trickle-down theory more specifically targets taxes on the upper end of the economic spectrum. The term "trickle-down" originated as a joke by humorist Will Rogers and today is often used to criticize economic policies that favor the wealthy or privileged while being framed as good for the average citizen. David Stockman, who as Ronald Reagan's budget director championed Reagan's tax cuts at first, later became critical of them and told journalist William Greider that "supply-side economics" is the trickle-down idea: Political opponents of the Reagan administration soon seized on this language in an effort to brand the administration as caring only about the wealthy. Some studies suggest a link between trickle-down economics and reduced growth. Trickle-down economics has been widely criticized, particularly by left-wing, centre-left and moderate politicians and economists, but also some right-wing politicians. A 2019 study in the Journal of Political Economy found, contrary to trickle-down theory, that "the positive relationship between tax cuts and employment growth is largely driven by tax cuts for lower-income groups and that the effect of tax cuts for the top 10 percent on employment growth is small."

9.0K
02 Dec 2022

Topic Review

Aarne–Thompson Classification Systems

The Aarne–Thompson classification systems are indices used to classify folktales: the Aarne–Thompson Motif-Index (catalogued by alphabetical letters followed by numerals), the Aarne–Thompson Tale Type Index (cataloged by AT or AaTh numbers), and the Aarne–Thompson–Uther classification system (developed in 2004 and cataloged by ATU numbers). They are named after their authors, Antti Aarne, Stith Thompson, and Hans-Jörg Uther. The indices are used in folkloristics to organize, classify, and analyze folklore narratives and are essential tools for folklorists, as Alan Dundes explained in 1997 about the first two indices, "the identification of folk narratives through motif and/or tale type numbers has become an international sine qua non among bona fide folklorists".

9.0K
05 Dec 2022

Topic Review

Mass media refers to a diverse range of communication channels that transmit information and entertainment content to a large audience. This encompasses traditional mediums such as newspapers, television, and radio, as well as modern digital platforms like the internet and social media. Mass media plays a crucial role in shaping public opinion, disseminating news, and influencing societal norms on a global scale.

9.0K
25 Jan 2024

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