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Topic Review
Unmanned Systems
An Unmanned System (US) or Vehicle (UV) can be defined as an “electro-mechanical system, with no human operator aboard, that is able to exert its power to perform designed missions”
  • 12.6K
  • 17 Mar 2021
Topic Review
Microstructure of Ni-Based Superalloy
To understand the behaviour of the especially complex Ni-based superalloys at high-homologous temperatures it is necessary to characterize their microstructure in fully heat-treatment condition. Detection and characterization of precipitates even nano-precipitates is essential in the study of creep and fatigue degradation. Without the knowledge about the phase composition of material, it is problematic to predict the microstructure evolution during long-term service. The main aim of this work was to perform the comprehensive characterization of equiaxed Ni-based superalloy René 108 from micro- to atomic-scale resolution by using analytical microscopy techniques.    
  • 12.5K
  • 20 Dec 2020
Topic Review
Philistinism
In the fields of philosophy and æsthetics, the derogatory term philistinism describes “the manners, habits, and character, or mode of thinking of a philistine”, manifested as an anti-intellectual social attitude that undervalues and despises art and beauty, intellect and spirituality. A philistine person is a man or woman of smugly narrow mind and of conventional morality whose materialistic views and tastes indicate a lack of and an indifference to cultural and æsthetic values. Since the 19th century, the contemporary denotation of philistinism, as the behaviour of "ignorant, ill-behaved persons lacking in culture or artistic appreciation, and only concerned with materialistic values" derives from Matthew Arnold's adaptation to English of the German word Philister, as applied by university students in their antagonistic relations with the townspeople of Jena, Germany, where, in 1689, a row resulted in several deaths. In the aftermath, the university cleric addressed the town-vs-gown matter with an admonishing sermon "The Philistines Be Upon Thee", drawn from the Book of Judges (Chapt. 16, 'Samson vs the Philistines'), of the Tanakh and of the Christian Old Testament. In Word Research and Word History, the philologist Friedrich Kluge said that the word philistine originally had a positive meaning that identified a tall and strong man, such as Goliath; later the meaning changed to identify the "guards of the city".
  • 12.5K
  • 22 Nov 2022
Topic Review
Pole Shift Hypothesis
The cataclysmic pole shift fringe theory suggests that there have been geologically rapid shifts in the relative positions of the modern-day geographic locations of the poles and the axis of rotation of the Earth, creating calamities such as floods and tectonic events. There is evidence of precession and changes in axial tilt, but this change is on much longer time-scales and does not involve relative motion of the spin axis with respect to the planet. However, in what is known as true polar wander, the solid Earth can rotate with respect to a fixed spin axis. Research shows that during the last 200 million years a total true polar wander of some 30° has occurred, but that no super-rapid shifts in the Earth's pole were found during this period. A characteristic rate of true polar wander is 1° or less per million years. Between approximately 790 and 810 million years ago, when the supercontinent Rodinia existed, two geologically rapid phases of true polar wander may have occurred. In each of these, the magnetic poles of the Earth shifted by approximately 55°.
  • 12.5K
  • 10 Oct 2022
Topic Review
Meanings of Minor Planet Names: 1–1000
As minor planet discoveries are confirmed, they are given a permanent number by the IAU's Minor Planet Center (MPC), and the discoverers can then submit names for them, following the IAU's naming conventions. The list below concerns those minor planets in the specified number-range that have received names, and explains the meanings of those names. Official naming citations of newly named small Solar System bodies are published in MPC's Minor Planet Circulars several times a year. Recent citations can also be found on the JPL Small-Body Database (SBDB). Until his death in 2016, German astronomer Lutz D. Schmadel compiled these citations into the Dictionary of Minor Planet Names (DMP) and regularly updated the collection. Based on Paul Herget's The Names of the Minor Planets, Schmadel also researched the unclear origin of numerous asteroids, most of which had been named prior to World War II.  This article incorporates public domain material from the United States Government document "SBDB". New namings may only be added after official publication as the preannouncement of names is condemned by the Committee on Small Body Nomenclature.
  • 12.5K
  • 25 Oct 2022
Topic Review
Phanerozoic
The Phanerozoic Eon is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. It covers 541 million years to the present and began with the Cambrian Period when animals first developed hard shells preserved in the fossil record. The time before the Phanerozoic, called the Precambrian, is now divided into the Hadean, Archaean and Proterozoic eons. The time span of the Phanerozoic starts with the sudden appearance of fossilized evidence of a number of animal phyla; the evolution of those phyla into diverse forms; the emergence and development of complex plants; the evolution of fish; the emergence of insects and tetrapods; and the development of modern fauna. Plant life on land appeared in the early Phanerozoic eon. During this time span, tectonic forces caused the continents to move and eventually collect into a single landmass known as Pangaea (the most recent supercontinent), which then separated into the current continental landmasses.
  • 12.5K
  • 08 Oct 2022
Topic Review
Battery Management System Subsystems and Their Influence
As the battery provides the entire propulsion power in electric vehicles (EVs), the utmost importance should be ascribed to the battery management system (BMS) which controls all the activities associated with the battery. 
  • 12.5K
  • 28 Jun 2022
Topic Review
Human Well-Being
The definition of human well-being is diverse and is often used interchangeably with happiness, human welfare, standard of living or quality of life and has become an all-around term to measure and promote human lifestyle.
  • 12.5K
  • 25 Feb 2021
Topic Review
Great Soviet Encyclopedia
The Great Soviet Encyclopedia (GSE; Russian: Большая советская энциклопедия, БСЭ, Bolshaya sovetskaya entsiklopediya) is one of the largest Russian-language encyclopedias, published by the Soviet state from 1926 to 1990, and again since 2002 by Russia (under the name Bolshaya Rossiyskaya entsiklopediya or Great Russian Encyclopedia). The GSE claimed to be "the first Marxist-Leninist general-purpose encyclopedia".
  • 12.5K
  • 31 Oct 2022
Topic Review
Henderson–Hasselbalch Equation
In chemistry, the Henderson–Hasselbalch equation describes the derivation of pH as a measure of acidity (using pKa, the negative log of the acid dissociation constant) in biological and chemical systems. The equation is also useful for estimating the pH of a buffer solution and finding the equilibrium pH in acid-base reactions (it is widely used to calculate the isoelectric point of proteins). The equation is given by: Here, [HA] is the molar concentration of the undissociated weak acid, [A⁻] is the molar concentration (molarity, M) of this acid's conjugate base and pKa is −log10 Ka where Ka is the acid dissociation constant, that is: In these equations, A⁻ denotes the ionic form of the relevant acid. Bracketed quantities such as [base] and [acid] denote the molar concentration of the quantity enclosed.
  • 12.5K
  • 14 Oct 2022
Topic Review
Positive Impact Organizations
Positive Impact Organizations broaden their purposes and their value creation to embrace strong sustainability, thereby contributing to economic, social, and environmental value. "Positive impact" is defined by products and services that are created with the purpose of solving societal problems. It reflects the shift from reducing an organization’s negative footprint to achieving a significant net positive impact on society and the planet. 
  • 12.4K
  • 30 Aug 2021
Topic Review
NASDAQ Composite
The NASDAQ Composite (ticker symbol ^IXIC) is a stock market index of the common stocks and similar securities (e.g. ADRs, tracking stocks, limited partnership interests) listed on the Nasdaq stock market. Along with the Dow Jones Industrial Average and S&P 500 it is one of the three most-followed indices in US stock markets. The composition of the NASDAQ Composite is heavily weighted towards information technology companies. The NASDAQ-100, whose components are a subset of the NASDAQ Composite's, accounts for over 90% of the NASDAQ Composite's movement, and there are many ETFs tracking its performance. The composite itself is calculated by taking the sum of the products of closing price and index share(capitalization-weighted) of all of the over 2500 securities in the index. The sum is then divided by a divisor which just serves to reduce the order of magnitude of the result.
  • 12.4K
  • 01 Dec 2022
Topic Review
Impacts of Brick Making on Environment
The brick making industry, despite its contribution to environmental pollution, plays a major role in the economic growth of many nations, with the traditional technology accounting for a significant proportion of the total clay brick production. This writeup gives an overview of the origin of brickmaking, its socioeconomic importance, the environmental impacts and improvements made in the art of brickmaking over the years. The environmental impacts from brickmaking cannot be overruled, however, this impacts could be minimized and managed  through the adoption of more sustainable and environmentally friendly firing innovative.
  • 12.4K
  • 23 Nov 2021
Topic Review
Working Principle of Hydraulic Control System
Hydraulic control systems are a feedback control system that uses hydraulic components as control and execution components, and hydraulic oil as the working medium for energy transmission. The movement of hydraulic actuators refers to the system output (including displacement, velocity, acceleration, and force), which is transmitted to the controller through feedback components. The input signal of the control component is adjusted according to the error size, so that the system output can automatically, quickly, and accurately track the system input instructions. Hydraulic control systems are classified into pump-controlled hydraulic control systems and valve-controlled hydraulic control systems based on their various control modes and valve components.
  • 12.4K
  • 18 Dec 2023
Topic Review
Force Field
In the context of chemistry and molecular modelling, a force field is a computational method that is used to estimate the forces between atoms within molecules and also between molecules. More precisely, the force field refers to the functional form and parameter sets used to calculate the potential energy of a system of atoms or coarse-grained particles in molecular mechanics, molecular dynamics, or Monte Carlo simulations. The parameters for a chosen energy function may be derived from experiments in physics and chemistry, calculations in quantum mechanics, or both. Force fields are interatomic potentials and utilize the same concept as force fields in classical physics, with the difference that the force field parameters in chemistry describe the energy landscape, from which the acting forces on every particle are derived as a gradient of the potential energy with respect to the particle coordinates. All-atom force fields provide parameters for every type of atom in a system, including hydrogen, while united-atom interatomic potentials treat the hydrogen and carbon atoms in methyl groups and methylene bridges as one interaction center. Coarse-grained potentials, which are often used in long-time simulations of macromolecules such as proteins, nucleic acids, and multi-component complexes, sacrifice chemical details for higher computing efficiency.
  • 12.4K
  • 10 Nov 2022
Topic Review
M2 Browning
The M2 Machine Gun or Browning .50 Caliber Machine Gun is a heavy machine gun designed toward the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, which was chambered for the .30-06 cartridge. The M2 uses the much larger and much more powerful .50 BMG cartridge, which was developed alongside and takes its name from the gun itself (BMG standing for Browning Machine Gun). It has been referred to as "Ma Deuce", in reference to its M2 nomenclature. The design has had many specific designations; the official designation for the current infantry type is Browning Machine Gun, Cal. .50, M2, HB, Flexible. It is effective against infantry, unarmored or lightly armored vehicles and boats, light fortifications and low-flying aircraft. The Browning .50 caliber machine gun has been used extensively as a vehicle weapon and for aircraft armament by the United States from the 1930s to the present. It was heavily used during World War II, the Korean War, the Vietnam War, the Falklands War, the Soviet–Afghan War, the Gulf War, the Iraq War and the War in Afghanistan in the 2000s and 2010s. It is the primary heavy machine gun of NATO countries, and has been used by many other countries as well. The M2 has been in use longer than any other firearm in U.S. inventory except the .45 ACP M1911 pistol, also designed by John Browning. The current M2HB is manufactured in the U.S. by General Dynamics and U.S. Ordnance for use by the U.S. government, and for allies via Foreign Military Sales, as well as foreign manufacturers such as FN Herstal.
  • 12.4K
  • 05 Dec 2022
Topic Review
Anatta
In Buddhism, the term anattā (Pali) or anātman (Sanskrit) refers to the doctrine of "non-self", that there is no unchanging, permanent self, soul or essence in phenomena. It is one of the seven beneficial perceptions in Buddhism, and one of the three marks of existence along with dukkha (suffering) and anicca (impermanence). The Buddhist concept of anatta or anatman is one of the fundamental differences between Buddhism and Hinduism, with the latter asserting that atman (self, soul) exists.
  • 12.4K
  • 15 Nov 2022
Topic Review
Microalgae Cell Disruption Methods
Microalgae are unicellular or simple multicellular photosynthetic microorganisms, which can normally be found in aquatic environments such as freshwater, seawater, or hypersaline lakes. These organisms can be eukaryotic or prokaryotic, the latter being the cyanobacteria, which are commonly referred to as microalgae.  The nature of the cell wall of a given microalgae species can vary, making it easier or harder to access its valuable contents. The rigidity of the cell wall can be provided, for example, by high levels of polysaccharides in the cell wall structure, such as glucose and mannose, present in Chlorella zofingiensis, or by complex sugars composition such as arabinose, galactose, rhamnose, mannose and xylose, as found in Tetraselmis suecia and T. striata. Algaenan or sporopollein is another extremely resistant biopolymer, a non-hydrolyzable biopolymer, composed of long ω-hydroxy fatty acids chains linked by several types of chemical bond, which confer its rigid properties, and that can be found in some species such as Chlorella spp., Nannochloropsis galditana and Scenedesmus spp. Arthorspira spp. cell wals contain peptidoglycan, being less rigid and, consequently, more susceptible to degradation. Thus, several methods can be applied to breakdown such molecules that, being part of the cell wall, present different level of rigidity and confer them protection against environment factors. The cell wall disruption methods include physical, chemical, enzymatic approaches. In this entry, it will be presented a brief description of these methods.
  • 12.4K
  • 29 Jan 2021
Topic Review
Intergeneric Hybrid
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes. A few animal species and many plant species, however, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled. Human impact on the environment has resulted in an increase in the interbreeding between regional species, and the proliferation of introduced species worldwide has also resulted in an increase in hybridisation. This genetic mixing may threaten many species with extinction, while genetic erosion from monoculture in crop plants may be damaging the gene pools of many species for future breeding. A form of often intentional human-mediated hybridisation is the crossing of wild and domesticated species. This is common in both traditional horticulture and modern agriculture; many commercially useful fruits, flowers, garden herbs, and trees have been produced by hybridisation. One such flower, Oenothera lamarckiana, was central to early genetics research into mutationism and polyploidy. It is also more occasionally done in the livestock and pet trades; some well-known wild × domestic hybrids are beefalo and wolfdogs. Human selective breeding of domesticated animals and plants has resulted in the development of distinct breeds (usually called cultivars in reference to plants); crossbreeds between them (without any wild stock) are sometimes also imprecisely referred to as "hybrids". Hybrid humans existed in prehistory. For example, Neanderthals and anatomically modern humans are thought to have interbred as recently as 40,000 years ago. Mythological hybrids appear in human culture in forms as diverse as the Minotaur, blends of animals, humans and mythical beasts such as centaurs and sphinxes, and the Nephilim of the Biblical apocrypha described as the wicked sons of fallen angels and attractive women.
  • 12.3K
  • 10 Oct 2022
Topic Review
Cruise Tourism
Cruise tourism is one of the leading industries suffering from covid-19 recently. Cruise tourism uses cruise ships with elegant services and various entertainment facilities as a means of transportation for scenic coastal tourist destinations. In particular, in accordance with the recent trend of increasing the size of ships, cruise lines have expanded the size and facilities of ships, and have continued to increase the maximum number of boarding ships. The cruise travel process and intensive entertainment system turned out to be a tourism structure vulnerable to the covid-19 pandemic. Will cruise tourism be extinguished? Should we prepare for the post-Pandermic cruise tourism era?
  • 12.3K
  • 26 Oct 2020
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