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
Types of Aluminium Matrix Composites
Al alloy has very attractive properties required in the production of aerospace, automotive, electrical and electronic, sports and recreational components/equipment. Its low strength and low wear resistance have challenged its applications in some other critical industrial utilities. Nonetheless, the invention of metal composites has removed such barriers. The addition of one or more reinforcements to Al has helped in the creation of aluminium matrix composites (AMCs), which has not only increased the global utilization of Al alloy, but has been a major source of global revenue and job. 
  • 5.0K
  • 20 Oct 2022
Topic Review
Starch Modification
Currently, new methods for producing starch citrates with improved functional and rheological properties while maintaining the highest possible content of resistant starch are being sought. The entry presents an overview of recent studies on the production, properties. And applicability of starch citrates with special attention paid to their role as preparations of resistant starch (RS). The use of citric acid for modification of starch is better for the technology process, while using cross-linking is better than simply using esterification.It may be concluded that the work on starch citrate esters represent a topical and meaningful direction of investigations on modified starch preparations. The possibility of modifying starch preparations by esterification/cross-linking with citric acid allows for the production of modified starch, which can be used in the pharmaceutical, packaging, or food industries. Especially significant may be investigations of resistant starch produced via esterification with citric acid because this method produces preparations exhibiting significant resistance and, simultaneously, good functional properties, which are potentially applicable as health-promoting additives that increase the dietary fiber content of food products.
  • 5.0K
  • 27 Oct 2020
Topic Review
Photonic Laser Thruster
A photonic laser thruster (PLT) is an amplified photonic propulsion thruster for space propulsion that works on the principle of a photon-pushed sail, generating thrust directly from the momentum of a photon from a laser reflected from a mirror. The thruster, invented by Young K. Bae differs from other solar sail and laser propulsion thrusters in that an amplification process is used, in which the incident beam is re-used by being reflected by a stationary mirror, with an amplification stage at each reflection. Because of the recycling of energy, the photonic laser thruster has been demonstrated to be more energy efficient than other laser-pushed sail concepts. The near-term usage of the photonic laser thruster the earth-orbit applications include propellant-free and thrust-plume-contamination-free spacecraft maneuvering for precision formation flying, large optical and RF synthetic aperture construction, and stationkeeping. The usage of the photonic laser thruster for main space propulsion would require scaling-up of the laser power and controlling laser diffraction over interplanetary and interstellar distances. Photonic laser thrusters have a very high specific impulse, and can permit spacecraft to reach much higher speeds that approach a fraction of the light speed, unlike conventional rockets, which are limited by the Tsiolkovsky rocket equation.
  • 5.0K
  • 01 Nov 2022
Topic Review
Humic Substances
Humic substances are a very important part of our soil.  The topic is description of the structure of humic substances using NMR.  The NMR part is divided into two parts, liquid and solid state NMR.  The assignment of NMR spectra are discussed and the structural elements that can be deduced from the spectral information.  Principal Component Analysis is used as a tool to categorize the information.  Structural models are discussed.
  • 5.0K
  • 16 Jul 2024
Topic Review
Application of Analog-to-Digital Converter in Ultrasonic Imaging System
The ADC, a bridge between the analog world and the digital world, converts the analog signals to digital so that the analog signal in the baseband can be processed by the back-end computer or microprocessor.
  • 5.0K
  • 17 Jan 2022
Topic Review
Malayan Languages
The Malay or Malayan languages are a group of closely related languages spoken by Malays and related peoples across Brunei, Indonesia, Malaysia, Singapore, Southern Thailand and the far southern parts of the Philippines. They have traditionally been classified as Malay, Para-Malay, and Aboriginal Malay, but this reflects geography and ethnicity rather than a proper linguistic classification. The Malayan languages are mutually intelligible to varying extents, though the distinction between language and dialect is unclear in many cases. Para-Malay includes the Malayan languages of Sumatra. They are: Minangkabau, Central Malay (Bengkulu), Pekal, Musi (Palembang), Negeri Sembilan (Malaysia), and Duano’. Aboriginal Malay are the Malayan languages spoken by the Orang Asli (Proto-Malay) in Malaya. They are Jakun, Orang Kanaq, Orang Seletar, and Temuan. The other Malayan languages, included in neither of these groups, are associated with the expansion of the Malays across the archipelago. They include Malaccan Malay (Malaysian and Indonesian), Kedah Malay, Kedayan/Brunei Malay, Berau Malay, Bangka Malay, Jambi Malay, Kutai Malay, Loncong, Pattani Malay, and Banjarese. There are also several Malay-based creole languages, such as Betawi, Cocos Malay, Manado Malay and Sabah Malay, which may be more or less distinct from standard (Malaccan) Malay.
  • 5.0K
  • 13 Oct 2022
Topic Review
Myeloid-Derived Suppressor Cells
Myeloid-derived suppressor cells (MDSCs) are heterogeneous cells derived from bone marrow. They are precursors of dendritic cells, macrophages and/or granulocytes. They have the ability to significantly inhibit immune cell responses.
  • 5.0K
  • 27 Oct 2020
Topic Review
Equine Collagen
Equine collagen is referred to type I collagen extracted from horse tissues that, in the last two decades, aroused great scientific and industrial interest in the field of life-science and bioengineering as alternative to bovine collagen for the manufacture of implantable medical devices. Commonly used sources of collagen are represented by bovine and swine, but their limited applications because of the zoonosis transmission risks, the immune response and the religious constrains lead to the identification of other collagen sources. In this circumstance, type I collagen isolated from horse tendon recently gained interest as an attractive alternative, so that, although bovine- and porcine-derived collagens still remain the most common ones, more and more companies started to bring to market several of equine tendon collagen-based products. Its favorable structural properties, its well-known bioactivity, its freedom from zoonosis transmission risks and the ability to not trigger immune reactions make equine collagen particularly appealing in medicine, cosmetics and pharmaceuticals.
  • 5.0K
  • 17 Nov 2020
Topic Review
Structure, Spectral Properties and Chemistry of Spiropyrans
Spiropyrans (SP) are a well-studied class of photochromic compounds. These compounds are usually named in conformity with the IUPAC rules for nomenclature of heterocyclic spirocompounds, as derivatives of 1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-indoline] or 1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-indole].
  • 5.0K
  • 11 Jul 2023
Topic Review
Natural Phenols
Phenols are widespread in nature, being the major components of several plants and essential oils. Natural phenols’ anti-microbial, anti-bacterial, anti-oxidant, pharmacological and nutritional properties are, nowadays, well established. Hence, given their peculiar biological role, numerous studies are currently ongoing to overcome their limitations, as well as to enhance their activity.
  • 5.0K
  • 29 Sep 2021
Topic Review
Deformation
In physics, deformation is the continuum mechanics transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body. A deformation can occur because of external loads, intrinsic activity (e.g. muscle contraction), body forces (such as gravity or electromagnetic forces), or changes in temperature, moisture content, or chemical reactions, etc. Strain is related to deformation in terms of relative displacement of particles in the body that excludes rigid-body motions. Different equivalent choices may be made for the expression of a strain field depending on whether it is defined with respect to the initial or the final configuration of the body and on whether the metric tensor or its dual is considered. In a continuous body, a deformation field results from a stress field due to applied forces or because of some changes in the temperature field of the body. The relation between stress and strain is expressed by constitutive equations, e.g., Hooke's law for linear elastic materials. Deformations which cease to exist after the stress field is removed are termed as elastic deformation. In this case, the continuum completely recovers its original configuration. On the other hand, irreversible deformations remain. They exist even after stresses have been removed. One type of irreversible deformation is plastic deformation, which occurs in material bodies after stresses have attained a certain threshold value known as the elastic limit or yield stress, and are the result of slip, or dislocation mechanisms at the atomic level. Another type of irreversible deformation is viscous deformation, which is the irreversible part of viscoelastic deformation. In the case of elastic deformations, the response function linking strain to the deforming stress is the compliance tensor of the material.
  • 5.0K
  • 09 Oct 2022
Topic Review
Energy Technology
Energy technology is an interdisciplinary engineering science having to do with the efficient, safe, environmentally friendly, and economical extraction, conversion, transportation, storage, and use of energy, targeted towards yielding high efficiency whilst skirting side effects on humans, nature, and the environment. For people, energy is an overwhelming need, and as a scarce resource, it has been an underlying cause of political conflicts and wars. The gathering and use of energy resources can be harmful to local ecosystems and may have global outcomes. Energy is also the capacity to do work. We can get energy from food. Energy can be of different forms such as kinetic, potential, mechanical, heat, light etc. Energy is required for individuals and the whole society for lighting, heating, cooking, running, industries, operating transportation and so forth. Basically there are two types of energy depending on the source s they are; 1.Renewable Energy Sources 2.Non-Renewable Energy Sources
  • 5.0K
  • 11 Nov 2022
Topic Review
U-Boat Campaign (World War I)
The U-boat Campaign from 1914 to 1918 was the World War I naval campaign fought by German U-boats against the trade routes of the Allies. It took place largely in the seas around the British Isles and in the Mediterranean. The German Empire relied on imports for food and domestic food production (especially fertilizer) and the United Kingdom relied heavily on imports to feed its population, and both required raw materials to supply their war industry; the powers aimed, therefore, to blockade one another. The British had the Royal Navy which was superior in numbers and could operate on most of the world's oceans because of the British Empire, whereas the Imperial German Navy surface fleet was mainly restricted to the German Bight, and used commerce raiders and unrestricted submarine warfare to operate elsewhere. In the course of events in the Atlantic alone, German U-boats sank almost 5,000 ships with nearly 13 million gross register tonnage, losing 178 boats and about 5,000 men in combat. Other naval theatres saw U-boats operating in both the Far East and South East Asia, the Indian Ocean and the Mediterranean and North Seas.
  • 5.0K
  • 06 Dec 2022
Topic Review
South Korea's Green New Deal
Originally proposed as a post-COVID-19 stimulus plan, the Green New Deal is a sustainability-centered strategy for building a low-carbon and climate-neutral economy. The Green New Deal sets out eight targets to be accomplished under three strategic areas: green urban development, low-carbon decentralized energy, and innovative green industry. The Deal also takes measures to protect the people and sectors at a higher risk of being left behind in the process of the economic transition. It is an upgraded version of the “Green Growth” national policy, with more emphasis on sustainability in addition to the growth aspect.
  • 5.0K
  • 17 Dec 2020
Topic Review Peer Reviewed
Helen Nemanjić (1250–1314)
Queen Helen Nemanjić (?–Brnjaci near Zubin Potok, February 8, 1314) was a Serbian medieval queen and consort of King Stefan Uroš I (r. 1243–1276), the fifth ruler of the Serbian Nemanide dynasty. She was the mother of the kings Stefan Dragutin and Stefan Uroš II Milutin. Today, she is known as Helen of Anjou (Jelena Anžujska in Serbian) although her real name was most probably Heleni Angelina (Ελένη Aγγελίνα). She was the founder of the Serbian Orthodox monastery of Gradac as well as four Franciscan abbeys in Kotor, Bar, Ulcinj, and Shkodër. Together with her sons, Kings Stefan Dragutin and Stefan Uroš II Milutin she helpedrenovation of Benedictine abbey of Sts. Sergius and Bacchus near Shkodër on Boyana river in present-day Albania. After the death of her husband, she ruled Zeta and Travunija until 1306. She was known for her religious tolerance and charitable and educational endeavors. She was elevated to sainthood by the Serbian Orthodox Church. Along with Empress Helen, the wife of Serbian Emperor Stefan Uroš IV Dušan, Queen Helen was the most frequently painted woman of Serbian medieval art. Six of her portraits can be found in the monumental painting ensembles of the Serbian medieval monasteries of Sopoćani, Gradac, Arilje, Đurđevi Stupovi (Pillars of St. George), and Gračanica, as well as on two icons and one seal. Queen Helen is also the only female Serbian medieval ruler whose vita was included in the famous collection of the “Lives of Serbian Kings and Archbishops” by Archbishop Danilo II, a prominent church leader, warrior, and writer. 
  • 5.0K
  • 13 Apr 2022
Topic Review
Effects of Global Warming
The effects of global warming or climate damage include far-reaching and long-lasting changes to the natural environment, to ecosystems and human societies caused directly or indirectly by human emissions of greenhouse gases. It also includes the economic and social changes which stem from living in a warmer world. Human caused climate change is one of the threats to sustainability. Many physical impacts of global warming are already visible, including extreme weather events, glacier retreat, changes in the timing of seasonal events (e.g., earlier flowering of plants), sea level rise, and declines in Arctic sea ice extent. The future impact of global warming depends on the extent to which nations implement prevention efforts and reduce greenhouse gas emissions. Ocean acidification is not a consequence of global warming, but instead has the same cause: increasing atmospheric carbon dioxide. Climate change has already impacted ecosystems and humans as well. In combination with climate variability, it makes food insecurity worse in many places and puts pressure on fresh water supply. This in combination with extreme weather events, leads to negative effects on human health. Rising temperatures threaten development because of negative effects on economic growth in developing countries. The social impact of climate change will be further affected by society's efforts to prepare and adapt. Global warming already contributes to migration in different parts of the world. Near-term climate change policies significantly affect long-term climate change impacts. Stringent mitigation policies might be able to limit global warming (in 2100) to around 2 °C or below, relative to pre-industrial levels. Without mitigation, increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 °C. Higher magnitudes of global warming would be more difficult to adapt to, and would increase the risk of negative impacts.
  • 5.0K
  • 01 Nov 2022
Topic Review
Fluid Catalytic Cracking
The fluid catalytic cracking (FCC) process is an alternative olefin production technology, with lower CO2 emission and higher energy-saving.
  • 5.0K
  • 23 Feb 2021
Topic Review
Synthesis of Carbon Dots
There are many studies on the different synthesis methods of carbon dots. Each process aims to improve the synthesis strategy and optimize the reaction conditions so that the carbon dots are not only more cost-effective and eco-friendly, but also provide more excellent performance.
  • 5.0K
  • 08 Dec 2022
Topic Review
Sublevel Caving Production Scheduling
Production scheduling determines the most beneficial mining sequence over the life of mine. Developing a schedule that meets all mining aspects can substantially reduce mining costs and increase profitability. Among all underground mining methods, the sublevel caving (SLC) method is a common method with moderate development requirements, high production rate, and high degree of mechanization and flexibility. None of the manual planning methods and heuristic algorithms used in commercial software will lead to a truly optimal schedule. In sublevel caving, mathematical programming models, particularly mixed-integer programming, have been applied to provide an operationally feasible multi-time period's schedule. However, confined blasting conditions, chaotic material flow, and frequent mixing of ore and waste while loading broken ore at the drawpoint make sublevel caving method unique to produce a holistic plan.
  • 5.0K
  • 27 Aug 2021
Topic Review
Classification of Unmanned Systems
The autonomous and semi-autonomous multi-agent systems have as much variation and as wide a range of applications as those in the modern mechatronics and robotics fields do. The advance of collaborative swarms of Unmanned Ground Vehicles (UGVs) and drones that are able to operate, navigate, communicate, and even install and assemble “each other” as a symbiotic team will play a critical role in the industry, science, and society in the future
  • 5.0K
  • 08 Mar 2023
  • Page
  • of
  • 2794
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

Quick Survey

Encyclopedia MDPI is conducting a targeted survey to identify the specific barriers hindering efficient research. We invite you to spend 3 minutes defining the priorities for our next generation of structured knowledge tools.
Take Survey