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Porcelain Enamel Coatings
Porcelain enamel is an inorganic-type coating, which is applied to metals or glass for both decorative and functional purposes. This coating is a silica-based solidified glass mass obtained by high-temperature firing (temperature can range between 450 and 1200 °C depending on the substrate). Porcelain enamel coatings differ from ceramic coatings mainly by their glass structure and dilatation coefficient, and from organic paints mainly by the inorganic nature of the matrix and the chemical bond that exists between the coating and the substrate. 
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  • 18 Apr 2022
Topic Review
Realigning Election
In political science and political history, a realigning election (often called a critical election, political realignment, or critical realignment) is a set of sharp changes in party ideology, issues, party leaders, regional and demographic bases of power of political parties, and the structure or rules of the political system, such as voter eligibility or financing. The changes result in a new political power structure that lasts for decades, replacing an older dominant coalition. Scholars frequently invoke the concept in American elections and occasionally those of other countries. US examples include the 1896 presidential election, when the issues of the Civil War political system were replaced with those of the Populist and Progressive Era, and the 1932 election, when the Populist and Progressive Eras were replaced by the New Deal issues of New Deal liberalism and modern conservatism. Realigning elections typically separate (what are known in the field of comparative politics as) party systems—with 1828, for example, separating the First Party System and the Second Party System in the US. It is generally accepted that the United States has had five distinct party systems, each featuring two major parties attracting a consistent political coalition and following a consistent party ideology, separated by four realignments. Political realignments can be sudden (1–4 years) or can take place more gradually (5–20 years). Most often, however, particularly in V. O. Key Jr.'s (1955) original hypothesis, it is a single "critical election" that marks a realignment. By contrast, a gradual process is called a secular realignment. Political scientists and historians often disagree about which elections are realignments and what defines a realignment, and even whether realignments occur. The terms themselves are somewhat arbitrary, however, and usage among political scientists and historians does vary. In the US, Walter Dean Burnham argued for a 30–38 year "cycle" of realignments. Many of the elections often included in the Burnham 38-year cycle are considered "realigning" for different reasons. Other political scientists and quantitative elections analysts reject realignment theory altogether, arguing that there are no long-term patterns. Political scientist David R. Mayhew states, "Electoral politics is to an important degree just one thing after another ... Elections and their underlying causes are not usefully sortable into generation-long spans ... It is a Rip Van Winkle view of democracy that voters come awake only once in a generation ... It is too slippery, too binary, too apocalyptic, and it has come to be too much of a dead end." Sean Trende, senior elections analyst at RealClearPolitics, who argues against realignment theory and the "emerging Democratic majority" thesis proposed by journalist John Judis and political scientist Ruy Teixeira in his 2012 book The Lost Majority states, "Almost none of the theories propounded by realignment theorists has endured the test of time... It turns out that finding a 'realigning' election is a lot like finding an image of Jesus in a grilled-cheese sandwich – if you stare long enough and hard enough, you will eventually find what you are looking for." In May 2015, statistician and FiveThirtyEight editor-in-chief Nate Silver argued against a blue wall Electoral College advantage for the Democratic Party in the upcoming 2016 US presidential election, and in post-election analysis published in January 2017, Silver cited Trende in noting that "there are few if any permanent majorities" and both Silver and Trende argued that the "emerging Democratic majority" thesis led most news coverage and commentary preceding the election to overstate Hillary Clinton's chances of being elected.
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  • 17 Nov 2022
Topic Review
Fundamentals of Oxygen Reduction Reaction
Oxygen reduction reaction (ORR) has been the subject of huge investigation since it is at the heart of various energy conversion and storage systems such as fuel cells, metal-air batteries, and so on. The mechanistic pathway is governed not only by the oxygen adsorption mode, but it also depends on the dissociation barrier of the catalyst surface. 
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  • 02 Sep 2022
Topic Review
Tangential Quadrilateral
In Euclidean geometry, a tangential quadrilateral (sometimes just tangent quadrilateral) or circumscribed quadrilateral is a convex quadrilateral whose sides all can be tangent to a single circle within the quadrilateral. This circle is called the incircle of the quadrilateral or its inscribed circle, its center is the incenter and its radius is called the inradius. Since these quadrilaterals can be drawn surrounding or circumscribing their incircles, they have also been called circumscribable quadrilaterals, circumscribing quadrilaterals, and circumscriptible quadrilaterals. Tangential quadrilaterals are a special case of tangential polygons. Other less frequently used names for this class of quadrilaterals are inscriptable quadrilateral, inscriptible quadrilateral, inscribable quadrilateral, circumcyclic quadrilateral, and co-cyclic quadrilateral. Due to the risk of confusion with a quadrilateral that has a circumcircle, which is called a cyclic quadrilateral or inscribed quadrilateral, it is preferable not to use any of the last five names. All triangles can have an incircle, but not all quadrilaterals do. An example of a quadrilateral that cannot be tangential is a non-square rectangle. The section characterizations below states what necessary and sufficient conditions a quadrilateral must satisfy to be able to have an incircle.
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  • 09 Oct 2022
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.
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  • 30 Nov 2022
Topic Review
Dihedral (Aeronautics)
In aeronautics, dihedral is the angle between the left and right wings (or tail surfaces) of an aircraft. "Dihedral" is also used to describe the effect of sideslip on the rolling of the aircraft. Dihedral angle is the upward angle from horizontal of the wings or tailplane of a fixed-wing aircraft. "Anhedral angle" is the name given to negative dihedral angle, that is, when there is a downward angle from horizontal of the wings or tailplane of a fixed-wing aircraft. Dihedral angle has a strong influence on dihedral effect, which is named after it. Dihedral effect is the amount of roll moment produced in proportion to the amount of sideslip. Dihedral effect is a critical factor in the stability of an aircraft about the roll axis (the spiral mode). It is also pertinent to the nature of an aircraft's Dutch roll oscillation and to maneuverability about the roll axis. Longitudinal dihedral is a comparatively obscure term related to the pitch axis of an airplane. It is the angle between the zero-lift axis of the wing and the zero-lift axis of the horizontal tail. Longitudinal dihedral can influence the nature of controllability about the pitch axis and the nature of an aircraft's phugoid-mode oscillation. When the term "dihedral" (of an aircraft) is used by itself it is usually intended to mean "dihedral angle". However, context may otherwise indicate that "dihedral effect" is the intended meaning.
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  • 27 Oct 2022
Topic Review
Synthetic Aperture Radar
SAR constellations 
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  • 24 Aug 2020
Topic Review
Hoveyda–Grubbs Catalyst
Hoveyda–Grubbs-type complexes, ruthenium catalysts for olefin metathesis, have gained increased interest as a research target in the interdisciplinary research fields of chemistry and biology because of their high functional group selectivity in olefin metathesis reactions and stabilities in aqueous media.
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  • 26 Mar 2021
Topic Review
Support Vector Machine
In machine learning, support-vector machines (SVMs, also support-vector networks) are supervised learning models with associated learning algorithms that analyze data used for classification and regression analysis. The Support Vector Machine (SVM) algorithm is a popular machine learning tool that offers solutions for both classification and regression problems. Developed at AT&T Bell Laboratories by Vapnik with colleagues (Boser et al., 1992, Guyon et al., 1993, Vapnik et al., 1997), it presents one of the most robust prediction methods, based on the statistical learning framework or VC theory proposed by Vapnik and Chervonekis (1974) and Vapnik (1982, 1995). Given a set of training examples, each marked as belonging to one or the other of two categories, an SVM training algorithm builds a model that assigns new examples to one category or the other, making it a non-probabilistic binary linear classifier (although methods such as Platt scaling exist to use SVM in a probabilistic classification setting). An SVM model is a representation of the examples as points in space, mapped so that the examples of the separate categories are divided by a clear gap that is as wide as possible. New examples are then mapped into that same space and predicted to belong to a category based on the side of the gap on which they fall. In addition to performing linear classification, SVMs can efficiently perform a non-linear classification using what is called the kernel trick, implicitly mapping their inputs into high-dimensional feature spaces. When data are unlabelled, supervised learning is not possible, and an unsupervised learning approach is required, which attempts to find natural clustering of the data to groups, and then map new data to these formed groups. The support-vector clustering algorithm, created by Hava Siegelmann and Vladimir Vapnik, applies the statistics of support vectors, developed in the support vector machines algorithm, to categorize unlabeled data, and is one of the most widely used clustering algorithms in industrial applications.
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  • 14 Oct 2022
Topic Review
Solid Waste Management in Middle East Arab Countries
Solid waste production, specifically construction waste, in Middle Eastern Arab countries has dramatically increased. This is characterized by several factors, including rapid urbanization, common food wasting habits, diverse culture, lack of proper planning of solid waste processes, insufficient equipment, as well as lack of proper funding. The exponential growth in solid waste generation rates has led to hazards to health and the environment, causing issues related to air and water pollution under the already increasing pressure of climate change.
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  • 17 Nov 2022
Topic Review
Sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) mineral particles or rock fragments. Most sandstone is composed of quartz or feldspar (both silicates) because they are the most resistant minerals to weathering processes at the Earth's surface, as seen in Bowen's reaction series. Like uncemented sand, sandstone may be any color due to impurities within the minerals, but the most common colors are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions. Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Fine-grained aquifers, such as sandstones, are better able to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity. Quartz-bearing sandstone can be converted into quartzite through metamorphism, usually related to tectonic compression within orogenic belts.
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  • 15 Nov 2022
Topic Review
Face with Tears of Joy Emoji
thumb|Appearance in the EmojiOne emoji set|167x167px Face with Tears of Joy (😂) is an emoji featuring a jovial face laughing, while also crying out tears. It can also be used for joking and teasing. It is the most commonly used emoji on social media websites such as Facebook, Snapchat, Twitter and Instagram. The emoji is also variously known as the lol emoji, joy emoji, laughing emoji or the laughing crying emoji.
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  • 09 Nov 2022
Topic Review
Features New to Windows 7
Some of the new features included in Windows 7 are advancements in touch, speech and handwriting recognition, support for virtual hard disks, support for additional file formats, improved performance on multi-core processors, improved boot performance, and kernel improvements. Some of the features which are present in versions up to and including Windows Vista were removed or changed.
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  • 15 Nov 2022
Topic Review
House of Bonaparte
The House of Bonaparte (originally Buonaparte) was an imperial and royal European dynasty founded in 1804 by Italian noble Carlo Buonaparte and his son Napoleon I, a French military leader of Italian heritage who had risen to notability out of the French Revolution and who in 1804 transformed the First French Republic into the First French Empire, five years after his coup d'état of November 1799. Napoleon turned the Grande Armée against every major European power and dominated continental Europe through a series of military victories during the Napoleonic Wars. He installed members of his family on the thrones of client states, extending the power of the dynasty. The House of Bonaparte formed the Imperial House of France during the French Empire, together with some non-Bonaparte family members. In addition to holding the title of Emperor of the French, the Bonaparte dynasty held various other titles and territories during the Napoleonic Wars, including their ancestral Kingdom of Italy, the Kingdom of Spain, the Kingdom of Westphalia, the Kingdom of Holland, and the Kingdom of Naples. The dynasty held power for around a decade until the Napoleonic Wars began to take their toll. Making very powerful enemies, such as Austria, Britain, Russia, and Prussia, as well as royalist (particularly Bourbon) restorational movements in France, Spain, the Two Sicilies, and Sardinia, the dynasty eventually collapsed due to the final defeat of Napoleon at the Battle of Waterloo and the restoration of former dynasties by the Congress of Vienna. During the reign of Napoleon I, the Imperial Family consisted of the Emperor's immediate relations – his wife, son, siblings, and some other close relatives, namely Joachim Murat, Joseph Fesch, and Eugène de Beauharnais. Between 1852 and 1870, there was a Second French Empire, when a member of the Bonaparte dynasty again ruled France: Napoleon III, the youngest son of Louis Bonaparte. However, during the Franco-Prussian War of 1870–1871, the dynasty was again ousted from the Imperial Throne. Since that time, there has been a series of pretenders. Supporters of the Bonaparte family's claim to the throne of France are known as Bonapartists. Current head Jean-Christophe, Prince Napoléon, has a Bourbon mother.
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  • 11 Nov 2022
Topic Review
Ray-Finned Fish
Actinopterygii (/ˌæktɪnɒptəˈrɪdʒiaɪ/; from actino- 'having rays', and grc πτέρυξ (ptérux) 'wing, fins'), members of which are known as ray-finned fishes, is a clade (traditionally class or subclass) of the bony fishes. They comprise over 50% of living vertebrate species. The ray-finned fishes are so-called because their fins are webs of skin supported by bony or horny spines (rays), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii (lobe-finned fish). These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). By species count, actinopterygians dominate the vertebrates, and they comprise nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the deep sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm (0.3 in), to the massive ocean sunfish, at 2,300 kg (5,070 lb), and the long-bodied oarfish, at 11 m (36 ft). The vast majority of Actinopterygii (~99%) are teleosts.
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  • 29 Nov 2022
Topic Review
Aparigraha
In Hinduism and Jainism, aparigraha (Sanskrit: अपरिग्रह) is the virtue of non-possessiveness, non-grasping or non-greediness. Aparigrah is the opposite of parigrah, and refers to keeping the desire for possessions to what is necessary or important, depending on one's life stage and context. The precept of aparigraha is a self-restraint (temperance) from the type of greed and avarice where one's own material gain or happiness comes by hurting, killing or destroying other human beings, life forms or nature. Aparigraha is related to and in part a motivator of dāna (proper charity), both from giver's and receiver's perspective.
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  • 13 Oct 2022
Topic Review
Lost Lands
Lost lands can be continents, islands or other regions existing during prehistory, having since disappeared as a result of catastrophic geological phenomena or slowly rising sea levels since the end of the last Ice Age. Lost lands, where they existed, are supposed to have subsided into the sea, leaving behind only a few traces or legends. The term can also be extended to mythological lands generally, to underground civilizations, or even to whole planets. The classification of lost lands as continents, islands, or other regions is in some cases subjective; for example, Atlantis is variously described as either a "lost island" or a "lost continent". Lost land theories may originate in mythology or philosophy, or in scholarly or scientific theories, such as catastrophic theories of geology.
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  • 11 Oct 2022
Topic Review
Andhaka
In Hindu mythology, Andhaka (Sanskrit: अन्धक, IAST: andhaka, lit. he who darkens) often refer to a malevolent asura who is killed by Shiva for trying to abduct Parvati. His story finds mention in various Hindu texts, including Matsya Purana, Kurma Purana, Linga Purana and Shiva Purana. He is believed to have thousand heads, two thousand eyes, arms and feet.
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  • 17 Oct 2022
Topic Review
Vegetable Oils as Lubricants
Vegetable oils have been used as metalworking fluids (MWFs) for many years, particularly in small-scale metalworking operations and in industries where environmental regulations are strict. Before the development of modern MWFs, vegetable oils were one of the most common lubricants used for metalworking tools. The use of vegetable oils can be traced back to ancient civilizations such as Egypt, Greece, and Rome, where olive oil was commonly used to lubricate metal tools and weapons. 
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  • 19 Apr 2023
Topic Review
Hegemony
Hegemony (UK: /hɪˈɡɛməni, hɪˈdʒɛməni/, US: /hɪˈdʒɛməni/ (pronunciation (help·info)) or /ˈhɛdʒəˌmoʊni/) is the political, economic, or military predominance or control of one state over others. In Ancient Greece (8th century BC – 6th century AD), hegemony denoted the politico-military dominance of a city-state over other city-states. The dominant state is known as the hegemon. In the 19th century, hegemony came to denote the "Social or cultural predominance or ascendancy; predominance by one group within a society or milieu". Later, it could be used to mean "a group or regime which exerts undue influence within a society". Also, it could be used for the geopolitical and the cultural predominance of one country over others, from which was derived hegemonism, as in the idea that the Great Powers meant to establish European hegemony over Africa, Asia and Latin America. In cultural imperialism, the leader state dictates the internal politics and the societal character of the subordinate states that constitute the hegemonic sphere of influence, either by an internal, sponsored government or by an external, installed government. In international relations theory, hegemony denotes a situation of (i) great material asymmetry in favour of one state, that has (ii) enough military power to systematically defeat any potential contester in the system, (iii) controls the access to raw materials, natural resources, capital and markets, (iv) has competitive advantages in the production of value added goods, (v) generates an accepted ideology reflecting this status quo; and (vi) is functionally differentiated from other states in the system, being expected to provide certain public goods such as security, or commercial and financial stability. The Marxist theory of cultural hegemony, associated particularly with Antonio Gramsci, is the idea that the ruling class can manipulate the value system and mores of a society, so that their view becomes the world view (Weltanschauung): in Terry Eagleton's words, "Gramsci normally uses the word hegemony to mean the ways in which a governing power wins consent to its rule from those it subjugates". In contrast to authoritarian rule, cultural hegemony "is hegemonic only if those affected by it also consent to and struggle over its common sense".
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  • 10 Nov 2022
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