Your browser does not fully support modern features. Please upgrade for a smoother experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Methods of Residual Stress Measurement
This entry introduces several commonly used residual stress measurement methods.
  • 9.9K
  • 01 Nov 2020
Biography
Jack Parsons
John Whiteside Parsons (born Marvel Whiteside Parsons;[1] October 2, 1914 – June 17, 1952) was an American rocket engineer, chemist, and Thelemite occultist. Associated with the California Institute of Technology (Caltech), Parsons was one of the principal founders of both the Jet Propulsion Laboratory (JPL) and the Aerojet Engineering Corporation. He invented the first rocket engine to use a
  • 9.9K
  • 15 Nov 2022
Topic Review
Angle-Resolved Photoemission Spectroscopy (ARPES)
Angle-resolved photoemission spectroscopy (ARPES) is a vital technique in which spectra are collected from both the energy and momentum of photoemitted electrons and is indispensable for investigating the electronic band structure of solids. 
  • 9.9K
  • 08 Dec 2020
Topic Review
Biopolymers for Medical Applications
Biopolymers are the organic substances present in natural sources. The term biopolymer originates from the Greek words bio and polymer, representing nature and living organisms. Large macromolecules made up of numerous repeating units are known as biopolymers. As per the IUPAC definition, a macromolecule defines a single molecule. The biopolymers are found to be biocompatible and biodegradable, making them useful in different applications, such as edible films, emulsions, packaging materials in the food industry, and as drug transport materials, medical implants like medical implants organs, wound healing, tissue scaffolds, and dressing materials in pharmaceutical industries. 
  • 9.9K
  • 18 Mar 2022
Topic Review
Secular Humanism
Secular humanism, often simply called humanism, is a philosophy or life stance that embraces human reason, secular ethics, and philosophical naturalism while specifically rejecting religious dogma, supernaturalism, and superstition as the basis of morality and decision making. Secular humanism posits that human beings are capable of being ethical and moral without religion or belief in a deity. It does not, however, assume that humans are either inherently good or evil, nor does it present humans as being superior to nature. Rather, the humanist life stance emphasizes the unique responsibility facing humanity and the ethical consequences of human decisions. Fundamental to the concept of secular humanism is the strongly held viewpoint that ideology—be it religious or political—must be thoroughly examined by each individual and not simply accepted or rejected on faith. Along with this, an essential part of secular humanism is a continually adapting search for truth, primarily through science and philosophy. Many secular humanists derive their moral codes from a philosophy of utilitarianism, ethical naturalism, or evolutionary ethics, and some advocate a science of morality. Humanists International is the world union of more than one hundred humanist, rationalist, irreligious, atheist, Bright, secular, Ethical Culture, and freethought organizations in more than 40 countries. The "Happy Human" is recognized as the official symbol of humanism internationally, used by secular humanist organizations in every part of the world. Those who call themselves humanists are estimated to number between four and five million people worldwide.
  • 9.9K
  • 14 Oct 2022
Topic Review
AI Control Problem
In artificial intelligence (AI) and philosophy, the AI control problem is the issue of how to build AI systems such that they will aid their creators, and avoid inadvertently building systems that will harm their creators. One particular concern is that humanity will have to solve the control problem before a superintelligent AI system is created, as a poorly designed superintelligence might rationally decide to seize control over its environment and refuse to permit its creators to modify it after launch. In addition, some scholars argue that solutions to the control problem, alongside other advances in AI safety engineering, might also find applications in existing non-superintelligent AI. Major approaches to the control problem include alignment, which aims to align AI goal systems with human values, and capability control, which aims to reduce an AI system's capacity to harm humans or gain control. Capability control proposals are generally not considered reliable or sufficient to solve the control problem, but rather as potentially valuable supplements to alignment efforts.
  • 9.9K
  • 22 Nov 2022
Topic Review
Enzyme Based Biosensors
Enzyme-based biosensors were the earliest biosensors. In 1962, Clark proposed the idea of enzyme electrodes for a glucose sensor. Subsequently, enzyme-based biosensors have been experimenting a massive growth in several applications.
  • 9.9K
  • 29 Oct 2021
Topic Review
Maitreya
Template:Infobox Buddha Maitreya (Sanskrit), Metteyya (Pali), is regarded as a future Buddha of this world in Buddhist eschatology. In some Buddhist literature, such as the Amitabha Sutra and the Lotus Sutra, he is referred to as Ajita. According to Buddhist tradition, Maitreya is a bodhisattva who will appear on Earth in the future, achieve complete enlightenment, and teach the pure dharma. According to scriptures, Maitreya will be a successor to the present Buddha, Gautama Buddha (also known as Śākyamuni Buddha). The prophecy of the arrival of Maitreya refers to a time in the future when the dharma will have been forgotten by most on the terrestrial world. Maitreya has also been adopted for his millenarian role by many non-Buddhist religions in the past, such as the White Lotus, as well as by modern new religious movements, such as Yiguandao.
  • 9.8K
  • 07 Oct 2022
Topic Review
Eosinophil Structure and Biology
Eosinophils are granulocytes with unique biology. The fact that these cells have been largely preserved during evolution strongly suggests that they play relevant physiological functions. Eosinophils have traditionally been classified as effector cells with prevalent cytotoxic activity, although recent evidence indicates that these cells may play a role in a wide range of homeostatic and regulatory functions.
  • 9.8K
  • 09 Sep 2022
Topic Review
Dinosaur Behavior
Dinosaur behavior is difficult for paleontologists to study since much of paleontology is dependent solely on the physical remains of ancient life. However, trace fossils and paleopathology can give insight into dinosaur behavior. Interpretations of dinosaur behavior are generally based on the pose of body fossils and their habitat, computer simulations of their biomechanics, and comparisons with modern animals in similar ecological niches. As such, the current understanding of dinosaur behavior relies on speculation, and will likely remain controversial for the foreseeable future. However, there is general agreement that some behaviors which are common in crocodiles and birds, dinosaurs' closest living relatives, were also common among dinosaurs. Gregarious behavior was common in many dinosaur species. Dinosaurs may have congregated in herds for defense, for migratory purposes, or to provide protection for their young. There is evidence that many types of dinosaurs, including various theropods, sauropods, ankylosaurians, ornithopods, and ceratopsians, formed aggregations of immature individuals. Nests and eggs have been found for most major groups of dinosaurs, and it appears likely that dinosaurs communicated with their young, in a manner similar to modern birds and crocodiles. The crests and frills of some dinosaurs, like the marginocephalians, theropods and lambeosaurines, may have been too fragile to be used for active defense, and so they were likely used for sexual or aggressive displays, though little is known about dinosaur mating and territorialism. Most dinosaurs seem to have relied on land-based locomotion. A good understanding of how dinosaurs moved on the ground is key to models of dinosaur behavior; the science of biomechanics, in particular, has provided significant insight in this area. For example, studies of the forces exerted by muscles and gravity on dinosaurs' skeletal structure have investigated how fast dinosaurs could run, whether diplodocids could create sonic booms via whip-like tail snapping, and whether sauropods could float.
  • 9.8K
  • 31 Oct 2022
Topic Review
Slavic Native Faith's Theology and Cosmology
Slavic Native Faith (Rodnovery) has a theology that is generally monistic, consisting in the vision of an absolute, supreme God (Rod) who begets the universe and lives as the universe (pantheism and panentheism), present in all its phenomena. Polytheism, that is the worship of the gods or spirits, and ancestors, the facets of the supreme Rod generating all phenomena, is an integral part of Rodnovers' beliefs and practices. The swastika-like kolovrat is the symbol of Rodnovery. According to the studies of Boris Rybakov, whirl and wheel symbols, which also include patterns like the "six-petaled rose inside a circle" (e.g. ) and the "thunder mark" (gromovoi znak), represent the supreme Rod and its various manifestations (whether Triglav, Svetovid, Perun or other gods).
  • 9.8K
  • 21 Oct 2022
Topic Review
Nomadic Empire
Nomadic empires, sometimes also called steppe empires, Central or Inner Asian empires, were the empires erected by the bow-wielding, horse-riding, nomadic people in the Eurasian Steppe, from classical antiquity (Scythia) to the early modern era (Dzungars). They are the most prominent example of non-sedentary polities. Some nomadic empires consolidated by establishing a capital city inside a conquered sedentary state and then exploiting the existing bureaucrats and commercial resources of that non-nomadic society. In such a scenario, the originally nomadic dynasty may become culturally assimilated to the culture of the occupied nation before it is ultimately overthrown. Ibn Khaldun (1332–1406) described a similar cycle on a smaller scale in 1377 in his Asabiyyah theory. Historians of the early medieval period may refer to these polities as "khanates" (after khan, the title of their rulers). After the Mongol conquests of the 13th century the term orda ("horde") also came into use — as in "Golden Horde".
  • 9.8K
  • 25 Nov 2022
Topic Review
Basic Oxygen Furnace Slag Characteristics and Properties
Basic oxygen furnace slag is an significant environmental liability produced by the steel industry, considering the volume of material produced and its specific physical and chemical characteristics. To further understand the advantages and limitations of BOF slag aggregate and to establish its role in the replacement of natural sand in Portland cement concrete, the slag was characterized in depth in terms of both its physical and morphological properties.
  • 9.8K
  • 10 May 2023
Topic Review
Sweet Corn
Sweet corn (Zea mays convar. saccharata var. rugosa; also called sweetcorn, sugar corn and pole corn) is a cereal with a high sugar content. Sweet corn is the result of a naturally occurring recessive mutation in the genes which control conversion of sugar to starch inside the ENO of the corn kernel. Unlike field corn varieties, which are harvested when the kernels are dry and mature (dent stage), sweet corn is picked when immature (milk stage) and prepared and eaten as a vegetable, rather than a grain. Since the process of maturation involves converting sugar to starch, sweet corn stores poorly and must be eaten fresh, canned, or frozen, before the kernels become tough and starchy. It is one of the six major types of corn, the others being dent corn, flint corn, pod corn, popcorn, and flour corn.
  • 9.8K
  • 09 Oct 2022
Topic Review
Gaulish Language
Gaulish was an ancient Celtic language that was spoken in parts of Continental Europe before and during the period of the Roman Empire. In the narrow sense, Gaulish was the language spoken by the Celtic inhabitants of Gaul (modern-day France, Luxembourg, Belgium, most of Switzerland, Northern Italy, as well as the parts of the Netherlands and Germany on the west bank of the Rhine). In a wider sense, it also comprises varieties of Celtic that were spoken across much of central Europe ("Noric"), parts of the Balkans, and Anatolia ("Galatian"), which are thought to have been closely related. The more divergent Lepontic of Northern Italy has also sometimes been subsumed under Gaulish. Together with Lepontic and the Celtiberian language spoken in the Iberian Peninsula, Gaulish helps form the geographic group of Continental Celtic languages. The precise linguistic relationships among them, as well as between them and the modern Insular Celtic languages, are uncertain and a matter of ongoing debate because of their sparse attestation. Gaulish is found in some 800 (often fragmentary) inscriptions including calendars, pottery accounts, funeral monuments, short dedications to gods, coin inscriptions, statements of ownership, and other texts, possibly curse tablets. Gaulish texts were first written in the Greek alphabet in southern France and in a variety of the Old Italic script in northern Italy. After the Roman conquest of those regions, writing shifted to the use of the Latin alphabet. During his conquest of Gaul, Caesar reported that the Helvetii were in possession of documents in the Greek script, and all Gaulish coins used the Greek script until about 50 BC. Gaulish in Western Europe was supplanted by Vulgar Latin and various Germanic languages from around the 5th century AD onwards. It is thought to have gone extinct some time around the late 6th century.
  • 9.8K
  • 01 Dec 2022
Topic Review
Barrier Layer of Cu Interconnects
The barrier layer in Cu technology is essential to prevent Cu from diffusing into the dielectric layer at high temperatures; therefore, it must have a high stability and good adhesion to both Cu and the dielectric layer. In the past three decades, tantalum/tantalum nitride (Ta/TaN) has been widely used as an inter-layer to separate the dielectric layer and the Cu. However, to fulfill the demand for continuous down-scaling of the Cu technology node, traditional materials and technical processes are being challenged. Direct electrochemical deposition of Cu on top of Ta/TaN is not realistic, due to its high resistivity. Therefore, pre-deposition of a Cu seed layer by physical vapor deposition (PVD) or chemical vapor deposition (CVD) is necessary, but the non-uniformity of the Cu seed layer has a devastating effect on the defect-free fill of modern sub-20 or even sub-10 nm Cu technology nodes. New Cu diffusion barrier materials having ultra-thin size, high resistivity and stability are needed for the successful super-fill of trenches at the nanometer scale. In this review, we briefly summarize recent advances in the development of Cu diffusion-proof materials, including metals, metal alloys, self-assembled molecular layers (SAMs), two-dimensional (2D) materials and high-entropy alloys (HEAs). Also, challenges are highlighted and future research directions are suggested.
  • 9.8K
  • 30 Jul 2021
Topic Review
School Strike for the Climate
The school strike for the climate (Swedish: Skolstrejk för klimatet), also known variously as Fridays for Future (FFF), Youth for Climate, Climate Strike or Youth Strike for Climate, is an international movement of school students who take time off from class on Fridays to participate in demonstrations to demand action from political leaders to take action to prevent climate change and for the fossil fuel industry to transition to renewable energy. Publicity and widespread organising began after Swedish schoolgirl Greta Thunberg staged a protest in August 2018 outside the Swedish Riksdag (parliament), holding a sign that read "Skolstrejk för klimatet" ("School strike for the climate"). A global strike on 15 March 2019 gathered more than one million strikers. Around 2200 strikes were organised in 125 countries. On 24 May 2019, the second global strike took place, in which 1600 events across 150 countries drew hundreds of thousands of protesters. The events were timed to coincide with the 2019 European Parliament election. The 2019 Global Week for Future was a series of 4500 strikes across over 150 countries, focused around Friday 20 September and Friday 27 September. Likely the largest climate strikes in world history, 20 September strikes gathered roughly 4 million protesters, many of them schoolchildren, including 1.4 million people on strike in Germany. On 27 September, an estimated 2 million people participated in demonstrations worldwide, including over 1 million protesters in Italy and several hundred thousand protesters in Canada.
  • 9.8K
  • 06 Dec 2022
Topic Review
Meaning and Determination of Electrode Surface Area
The interfacial contact area between an electronically conducting and an ionically conducting phase is the area where an electrode meets an electrolyte or an electrolyte solution. This area may differ significantly from the geometric, microscopic, real, or true surface area of the electronically conducting solid (the electrode) determined with a variety of experimental methods. This contact area may also differ from the electrochemically active surface area. These different surface or interface areas are relevant in electrochemical energy conversion and storage. They are not necessarily identical; there are even no simple relationships between them. This entry provides an overview of the various terms, briefly describes experimental methods for their determination and puts the data in perspective with respect to electrochemical energy conversion and storage.
  • 9.8K
  • 24 Feb 2023
Topic Review
KH-11 Kennen
The KH-11 KENNEN (later renamed CRYSTAL, then Evolved Enhanced CRYSTAL System, and codenamed 1010 and Key Hole) is a type of reconnaissance satellite first launched by the American National Reconnaissance Office in December 1976. Manufactured by Lockheed in Sunnyvale, California, the KH-11 was the first American spy satellite to use electro-optical digital imaging, and so offer real-time optical observations. Later KH-11 satellites have been referred to by outside observers as KH-11B or KH-12, and by the names "Advanced KENNEN", "Improved Crystal" and "Ikon". Official budget documents refer to the latest generation of electro-optical satellites as Evolved Enhanced CRYSTAL System. The Key Hole series was officially discontinued in favor of a random numbering scheme after repeated public references to KH-7 Gambit, KH-8 Gambit-3, KH-9 Hexagon, and KH-11 satellites. The capabilities of the KH-11 are highly classified, as are images they produce. The satellites are believed to have been the source of some imagery of the Soviet Union and China made public in 1997; images of Sudan and Afghanistan made public in 1998 related to the response to the 1998 U.S. embassy bombings; and a 2019 photo, revealed by President Donald Trump, of a failed Iranian rocket launch.
  • 9.8K
  • 09 Oct 2022
Topic Review
Spirit Spouse
The spirit spouse is one of the most widespread elements of shamanism, distributed through all continents and at all cultural levels. Often, these spirit husbands/wives are seen as the primary helping spirits of the shaman, who assist them in their work, and help them gain power in the world of spirit. The relationships shamans have with their spirit spouses may be expressed in romantic, sexual, or purely symbolic ways, and may include gender transformation as a part of correctly pairing with their "spouse". Shamans report engaging with their spirit spouses through dreams, trance, and other ritual elements. In some cultures, gaining a spirit spouse is a necessary and expected part of initiation into becoming a shaman. Evidence of spirit spouses may be seen in non-shamanic cultures as well, including dreams about Christ by nuns, who are considered to be "brides of Christ".
  • 9.8K
  • 16 Nov 2022
  • Page
  • of
  • 2798
Featured Entry Collections
>>

Featured Reprints

>>
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Medieval Royal Iconography
Academic Video Service
Feedback