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Topic Review

Influence Radius of Pumping Well

The influence radius was originally used in the calculation of some hydrogeological parameters but, owing to various coincidences that occur in practical situations, it has been considered that the parameterized influence radius is reasonable and convenient for calculations pertaining to actual production problems, and this misconception has perpetuated. However, by considering the continuity principle of flow, it can be proven that the parameterized influence radius does not exist. The influence radius is essentially the distance in the time–distance problem in physics and is influenced by the hydrogeological conditions and pumping conditions, which is different from the hydrogeological parameters reflecting the natural properties of aquifers, such as the porosity, specific yield, and hydraulic conductivity.

10.3K
18 Aug 2021

Topic Review

Water Footprint in Steel Industries

Steelmaking is a water-intensive process. The mean water intake against each ton of steel manufactured is ascertained as between 2 and 20 m3. Primarily, the stated requirement is in the form of make-up water to compensate for evaporation and mechanical losses and does not contribute to wastewater generation. Conversely, unit operations, such as rolling, continuous casting, pickling, etc., generate highly complex wastewater rich in polycyclic aromatic hydrocarbons (PAH), cyanide, ammonia, non-consumed acids, benzene, toluene, xylene, oil, grease, etc.

10.3K
15 Jun 2023

Topic Review

Armor-Piercing Ammunition

Armour-piercing ammunition (AP) is a type of projectile designed to penetrate either body armour or vehicle armour. From the 1860s to 1950s, a major application of armour-piercing projectiles was to defeat the thick armour carried on many warships and cause damage to their lightly-armoured interiors. From the 1920s onwards, armour-piercing weapons were required for anti-tank missions. AP rounds smaller than 20 mm are intended for lightly-armoured targets such as body armour, bulletproof glass and lightly-armoured vehicles. As tank armour improved during World War II, anti-vehicle rounds began to use a smaller but dense penetrating body within a larger shell, firing at very high muzzle velocity. Modern penetrators are long rods of dense material like tungsten or depleted uranium (DU) that further improves the terminal ballistics.

10.3K
12 Oct 2022

Topic Review

The Peshitta (Classical Syriac: ܦܫܝܛܬܐ‎ pšîṭtâ) is the standard version of the Bible for churches in the Syriac tradition. The consensus within biblical scholarship, though not universal, is that the Old Testament of the Peshitta was translated into Syriac from Hebrew, probably in the 2nd century AD, and that the New Testament of the Peshitta was translated from the Greek. This New Testament, originally excluding certain disputed books (2 Peter, 2 John, 3 John, Jude, Revelation), had become a standard by the early 5th century. The five excluded books were added in the Harklean Version (616 AD) of Thomas of Harqel. However, the 1905 United Bible Society Peshitta used new editions prepared by the Irish Syriacist John Gwynn for the missing books.

10.3K
08 Oct 2022

Topic Review

Magnetic Potential

The term magnetic potential can be used for either of two quantities in classical electromagnetism: the magnetic vector potential, or simply vector potential, A; and the magnetic scalar potential ψ. Both quantities can be used in certain circumstances to calculate the magnetic field B. The more frequently used magnetic vector potential is defined so that its curl is equal to the magnetic field: [math]\displaystyle{ \nabla \times \mathbf{A}=\mathbf{B}\, }[/math]. Together with the electric potential φ, the magnetic vector potential can be used to specify the electric field E as well. Therefore, many equations of electromagnetism can be written either in terms of the fields E and B, or equivalently in terms of the potentials φ and A. In more advanced theories such as quantum mechanics, most equations use potentials rather than fields. The magnetic scalar potential ψ is sometimes used to specify the magnetic H-field in cases when there are no free currents, in a manner analogous to using the electric potential to determine the electric field in electrostatics. One important use of ψ is to determine the magnetic field due to permanent magnets when their magnetization is known. With some care the scalar potential can be extended to include free currents as well. Historically, Lord Kelvin first introduced vector potential in 1851, along with the formula relating it to the magnetic field.

10.3K
29 Sep 2022

Topic Review

Popular Culture

Popular culture refers to the set of ideas, practices, images, and phenomena that are prevalent and widely accepted within a society at a given point in time. It encompasses various aspects of daily life, including entertainment, fashion, music, sports, and technology, reflecting the shared interests and preferences of the general public. Popular culture is dynamic and evolves over time, influenced by social, political, and technological developments, making it a key area of study within the realm of social science.

10.2K
25 Jan 2024

Topic Review

Roasting Processes for Lithium Extraction

This entry describes the main thermal treatments for processing spodumene in order to get easier lithium extraction by hydrometallurgical routes. It shows the importance of the thermal treatment and the need to reduce the energy consumption of this operation.

10.2K
18 Nov 2020

Topic Review

Defect Types and Mechanism of Wind Turbine Blades

There are two main reasons for the damage to wind turbine blades. On the one hand, the wind turbine is in a harsh external environment, and the damage faults are directly caused by external factors, such as strong wind, rain or snow, salt fog, lightning strike, freezing, sandstorm, insects, etc. The other is the invisible defects caused by process problems in the technology of man-made manufacturing. These invisible defects are subject to repeated high loads and harsh external environments during the installation and operation of the wind turbine. The gradual expansion of invisible defects can lead to damage. Due to the complexity of the blade material and structure, each damage type may be caused by a combination of causes. Different defects in the production process and different operating conditions will cause different damage types.

10.2K
28 Sep 2022

Topic Review

Cholera Outbreaks and Pandemics

Seven cholera pandemics have occurred in the past 200 years, with the first pandemic originating in India in 1817. Additionally, there have been many documented cholera outbreaks, such as a 1991–1994 outbreak in South America and, more recently, the 2016–2021 Yemen cholera outbreak. Although much is known about the mechanisms behind the spread of cholera, this has not led to a full understanding of what makes cholera outbreaks happen in some places and not others. Lack of treatment of human feces and lack of treatment of drinking water greatly facilitate its spread. Bodies of water have been found to serve as a reservoir, and seafood shipped long distances can spread the disease. Between 1816 and 1923, the first six cholera pandemics occurred consecutively and continuously over time. Increased commerce, migration, and pilgrimage are credited for its transmission. Late in this period (particularly 1879–1883), major scientific breakthroughs toward the treatment of cholera develop: the first immunization by Pasteur, the development of the first cholera vaccine, and identification of the bacterium Vibrio cholerae by Filippo Pacini and Robert Koch. After a long hiatus, a seventh cholera pandemic spread in 1961. The pandemic subsided in the 1970s, but continued on a smaller scale. Outbreaks occur across the developing world to the current day. Epidemics occurred after wars, civil unrest, or natural disasters, when water and food supplies had become contaminated with Vibrio cholerae, and also due to crowded living conditions and poor sanitation. Deaths in India between 1817 and 1860 in the first three pandemics of the nineteenth century, are estimated to have exceeded 15 million people. Another 23 million died between 1865 and 1917, during the next three pandemics. Cholera deaths in the Russian Empire during a similar time period exceeded 2 million.

10.2K
20 Oct 2022

Topic Review

Degeneration Theory

Social degeneration was a widely influential concept at the interface of the social and biological sciences in the 18th and 19th centuries. During the 18th century, scientific thinkers including George Louis Leclerc, comte de Buffon, Johann Friedrich Blumenbach, and Immanuel Kant argued that humans shared a common origin but had degenerated over time due to differences in climate. This theory provided an explanation of where humans came from and why some people appeared different from others. In contrast, degenerationists in the 19th century feared that civilization might be in decline and that the causes of decline lay in biological change. These ideas derived from pre-scientific concepts of heredity ("hereditary taint") with Lamarckian emphasis on biological development through purpose and habit. Degeneration concepts were often associated with authoritarian political attitudes, including militarism and scientific racism, and a preoccupation with eugenics. The theory originated in racial concepts of ethnicity, recorded in the writings of such medical scientists as Johann Blumenbach and Robert Knox. From the 1850s, it became influential in psychiatry through the writings of Bénédict Morel, and in criminology with Cesare Lombroso. By the 1890s, in the work of Max Nordau and others, degeneration became a more general concept in social criticism. It also fed into the ideology of ethnic nationalism, attracting, among others, Maurice Barrès, Charles Maurras and the Action Française. Alexis Carrel, a French Nobel Laureate in Medicine, cited national degeneration as a rationale for a eugenics programme in collaborationist Vichy France. The meaning of degeneration was poorly defined, but can be described as an organism's change from a more complex to a simpler, less differentiated form, and is associated with 19th-century conceptions of biological devolution. In scientific usage, the term was reserved for changes occurring at a histological level – i.e. in body tissues. Although rejected by Charles Darwin, the theory's application to the social sciences was supported by some evolutionary biologists, most notably Ernst Haeckel and Ray Lankester. As the 19th century wore on, the increasing emphasis on degeneration reflected an anxious pessimism about the resilience of European civilization and its possible decline and collapse.

10.2K
21 Oct 2022

Topic Review

Starlink (Satellite Constellation)

Starlink is a satellite constellation being constructed by American company SpaceX to provide satellite Internet access. The constellation will consist of thousands of mass-produced small satellites, working in combination with ground transceivers. SpaceX also plans to sell some of the satellites for military, scientific or exploratory purposes. (As of January 2020), SpaceX has deployed 182 satellites. They plan to deploy 60 more per Falcon 9 launch, with launches as often as every two weeks after late 2019. In total, nearly 12,000 satellites will be deployed by the mid-2020s, with a possible later extension to 42,000. The initial 12,000 satellites are planned to orbit in three orbital shells: first placing approximately 1,600 in a 550-kilometer-altitude (340 mi) shell, then approximately 2,800 Ku- and Ka-band spectrum satellites at 1,150 km (710 mi) and approximately 7,500 V-band satellites at 340 km (210 mi). Commercial operation could begin in 2020. Concerns have been raised about the long-term danger of space junk resulting from placing thousands of satellites in orbits above 1,000 kilometres (620 mi) and a possible impact on astronomy, although SpaceX is reportedly attempting to solve the issue. The total cost of the decade-long project to design, build and deploy the constellation was estimated by SpaceX in May 2018 to be about US$10 billion. Product development began in 2015, with the first two prototype test-flight satellites launched in February 2018. A second set of test satellites and the first large deployment of a piece of the constellation occurred on 24 May 2019 (UTC) when the first 60 operational satellites were launched. The SpaceX satellite development facility in Redmond, Washington, houses the Starlink research, development, manufacturing and on-orbit control operations.

10.2K
11 Nov 2022

Topic Review

Concept of Human Flourishing

Human flourishing is a thriving concept, whose use has greatly increased among academic researchers from a variety of fields, from the arts and humanities and psychology to the social and environmental sciences and economics. The rise of the concept was sparked by the positive psychology movement, which based it primarily on subjective and individual well-being; however, it was soon taken up by other currents, such as capabilities theory, reaching many social and collective concerns. Since 2016, the philosophical roots have especially energized the concept, maintaining the expansion of its use in fields related to the application of knowledge and management.

10.2K
01 Mar 2022

Topic Review

A paternoster (/ˈpeɪtərˈnɒstər/, /ˈpɑː-/, or /ˈpæ-/) or paternoster lift is a passenger elevator which consists of a chain of open compartments (each usually designed for two persons) that move slowly in a loop up and down inside a building without stopping. Passengers can step on or off at any floor they like. The same technique is also used for filing cabinets to store large amounts of (paper) documents or for small spare parts. The much smaller belt manlift which consists of an endless belt with steps and rungs but no compartments is also sometimes called a paternoster. The name paternoster ("Our Father", the first two words of the Lord's Prayer in Latin) was originally applied to the device because the elevator is in the form of a loop and is thus similar to rosary beads used as an aid in reciting prayers. The construction of new paternosters was stopped in the mid-1970s due to safety concerns, but public sentiment has kept many of the remaining examples open. By far most remaining paternosters are in Europe, with 230 examples in Germany, and 68 in the Czech Republic. Only three have been identified outside Europe: one in Malaysia, one in Sri Lanka, and another in Peru.

10.2K
01 Nov 2022

Topic Review

Photoplethysmography Sensors

The rapid advances in human-friendly and wearable photoplethysmography (PPG) sensors have facilitated the continuous and real-time monitoring of physiological conditions, enabling self-health care without being restricted by location.

10.2K
27 Apr 2021

Topic Review

Chemical Composition and Quality of Saffron

Saffron is the commercial name for the dried red stigmas of the Crocus sativus L. flower. It is appreciated for adding color, flavor, and a particular aroma to different food dishes or drinks (paella in Spain, Milanese risotto in Italy, lussekatter buns in Sweden, and alcoholic beverages). It is considered a high-priced condiment (1500–2200 euro/kg) due to the considerable labor involved in its production since it requires manual harvesting as well as a laborious handling process (sorting, drying, and storage). Saffron’s principal producers are Iran and Spain, whereas the leading importers are Spain, Hong Kong, and the United States. Saffron’s quality is essential for consumers in the food industry and is based on the concentration of its apocarotenoids and their respective sensory attributes: crocin’s coloring strength, picrocrocin’s bitter taste, and safranal’s aromatic intensity

10.2K
14 Nov 2022

Topic Review

Take This Lollipop

Take This Lollipop is a 2011 interactive horror short film and Facebook app written and directed by Jason Zada. It uses the Facebook Connect application to bring viewers themselves into the film, through use of pictures and messages from their own Facebook profiles. Starring actor Bill Oberst Jr. as 'The Facebook Stalker', the film acts to personalize and underscore the dangers inherent in posting too much personal information about oneself on the internet. The information gathered from a viewer's Facebook profile by the film's app is used once, and then deleted. The title is derived from the 1963 song "Please Little Girl Take This Lollipop", written and performed by singer-songwriter Bobby Jameson, which is used in the film. According to Zada, Take This Lollipop was taken offline "a few months" prior to August 2018. The film's website now hosts a Facebook post by him, saying that the data needed had become "quite hard to access" and had affected the functionality of the film.

10.2K
20 Oct 2022

Topic Review

In philosophy, transcendence is the basic ground concept from the word's literal meaning (from Latin), of climbing or going beyond, albeit with varying connotations in its different historical and cultural stages. It includes philosophies, systems, and approaches that describe the fundamental structures of being, not as an ontology (theory of being), but as the framework of emergence and validation of knowledge of being. "Transcendental" is a word derived from the scholastic, designating the extra-categorical attributes of beings.

10.2K
10 Nov 2022

Topic Review

Declaration of War

A declaration of war is a formal act by which one state goes to war against another. The declaration is a performative speech act (or the signing of a document) by an authorized party of a national government, in order to create a state of war between two or more states. The legality of who is competent to declare war varies between nations and forms of government. In many nations, that power is given to the head of state or sovereign. In other cases, something short of a full declaration of war, such as a letter of marque or a covert operation, may authorise war-like acts by privateers or mercenaries. The official international protocol for declaring war was defined in the Hague Convention (III) of 1907 on the Opening of Hostilities. Since 1945, developments in international law such as the United Nations Charter, which prohibits both the threat and the use of force in international conflicts, have made declarations of war largely obsolete in international relations. The UN Security Council, under powers granted in articles 24 and 25, and Chapter VII of the Charter, may authorize collective action to maintain or enforce international peace and security. Article 51 of the United Nations (UN) Charter also states that: "Nothing in the present Charter shall impair the inherent right to individual or collective self-defence if an armed attack occurs against a state." Few nations have formally declared war upon another since then. In addition to this, non-state or terrorist organizations may claim to or be described as "declaring war" when engaging in violent acts. These declarations may have no legal standing in themselves, but they may still act as a call to arms for supporters of these organizations.

10.2K
11 Dec 2025

Topic Review

The constellation Libra, known as the Scales or the Balance, is one of the 12 zodiac constellations representing an inanimate object. It is located in the southern sky and is associated with justice and balance. Libra is depicted as scales held by the Greek goddess of justice, Astraea, and is the only zodiac constellation named after an object rather than an animal or character from mythology.

10.2K
15 Mar 2024

Topic Review

History of Statistics

The history of statistics in the modern way is that it originates from the term statistics, found in 1749 in Germany. Although there have been changes to the interpretation of the word over time. The development of statistics is intimately connected on the one hand with the development of sovereign states, particularly European states following the peace of Westphalia (1648); and the other hand with the development of probability theory, which put statistics on a firm theoretical basis (see history of probability). In early times, the meaning was restricted to information about states, particularly demographics such as population. This was later extended to include all collections of information of all types, and later still it was extended to include the analysis and interpretation of such data. In modern terms, "statistics" means both sets of collected information, as in national accounts and temperature records, and analytical work which requires statistical inference. Statistical activities are often associated with models expressed using probabilities, hence the connection with probability theory. The large requirements of data processing have made statistics a key application of computing; see history of computing hardware. A number of statistical concepts have an important impact on a wide range of sciences. These include the design of experiments and approaches to statistical inference such as Bayesian inference, each of which can be considered to have their own sequence in the development of the ideas underlying modern statistics.

10.2K
19 Oct 2022

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