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Topic Review
Networked Control System
An NCS consists of control loops joined through communication networks in which both the control signal and the feedback signal are exchanged between the system and the controller.
  • 5.7K
  • 01 Apr 2021
Topic Review
Old Aramaic Language
Old Aramaic refers to the earliest stage of the Aramaic language, considered to give way to Middle Aramaic by the 3rd century (a conventional date is the rise of the Sasanian Empire in 224 AD). Emerging as the language of the city-states of the Arameans in the Levant in the Early Iron Age, Old Aramaic was adopted as a lingua franca, and in this role was inherited for official use by the Achaemenid Empire during classical antiquity. After the fall of the Achaemenid Empire, local vernaculars became increasingly prominent, fanning the divergence of an Aramaic dialect continuum and the development of differing written standards.
  • 5.6K
  • 21 Oct 2022
Topic Review
Media Ecology
Media ecology theory is the study of media, technology, and communication and how they affect human environments. The theoretical concepts were proposed by Marshall McLuhan in 1964, while the term media ecology was first formally introduced by Neil Postman in 1968. Ecology in this context refers to the environment in which the medium is used – what they are and how they affect society. Neil Postman states, "if in biology a 'medium' is something in which a bacterial culture grows (as in a Petri dish), in media ecology, the medium is 'a technology within which a [human] culture grows.'" In other words, "Media ecology looks into the matter of how media of communication affect human perception, understanding, feeling, and value; and how our interaction with media facilitates or impedes our chances of survival. The word ecology implies the study of environments: their structure, content, and impact on people. An environment is, after all, a complex message system which imposes on human beings certain ways of thinking, feeling, and behaving." Media ecology argues that media act as extensions of the human senses in each era, and communication technology is the primary cause of social change. McLuhan is famous for coining the phrase, "the medium is the message", which is an often-debated phrase believed to mean that the medium chosen to relay a message is just as important (if not more so) than the message itself. McLuhan proposed that media influence the progression of society, and that significant periods of time and growth can be categorized by the rise of a specific technology during that period. Additionally, scholars have compared media broadly to a system of infrastructure that connect the nature and culture of a society with media ecology being the study of "traffic" between the two.
  • 5.6K
  • 23 Oct 2022
Topic Review
Biomass Gasification
Lignocellulosic gasification is a valid thermochemical approach for the conversion of organic solid matter into a gaseous mixture that is constituted of hydrogen, carbon monoxide, carbon dioxide and methane, named synthetic gas or syngas. Although about 55% of syngas is still produced from coal, biomass utilization, especially lignocellulose, is constantly growing. Indeed, gasification could be potentially applied to all different kinds of lignocellulosic biomass, unlike other conversion technologies. Moreover, in the last few decades, a wide range of applications of syngas have been intensively studied. Syngas can be directly used as a combustible substance in power plants for heat and power production (steam cycle, co-combustion, combustion in gas turbines or internal combustion engines, high temperature fuel cells), which represents the most common use of biomass-derived syngas. However, syngas also represents a platform that can be employed in a broad range of chemical and microbial processes, leading to gaseous and liquid fuels, as well as to chemicals. Chemical process research has mainly focused on transportation fuel production from syngas, such as Fischer–Tropsch liquid fuels, hydrogen, methanol, dimethyl ether (DME), mixed alcohols, and synthetic natural gas (SNG). Instead, the biochemical conversion route consists of syngas fermentation in which obligate anaerobic microorganisms convert syngas into organic acids, alcohols, and other chemicals. The most commonly used microorganisms are acetogens, which use the Wood–Ljungdahl metabolic pathway. Syngas fermentation is defined as an indirect fermentation process because biomass is not fed directly into the fermenter, but it is previously converted into syngas through gasification. 
  • 5.6K
  • 17 Dec 2020
Topic Review
E-learning (Theory)
E-learning theory describes the cognitive science principles of effective multimedia learning using electronic educational technology.
  • 5.6K
  • 25 Nov 2022
Topic Review
Wearable Devices for Non-Invasive Sensing
The development of wearable sensors is aimed at enabling continuous real-time health monitoring, which leads to timely and precise diagnosis anytime and anywhere. Unlike conventional wearable sensors that are somewhat bulky, rigid, and planar, research for next-generation wearable sensors has been focused on establishing fully-wearable systems. To attain such excellent wearability while providing accurate and reliable measurements, fabrication strategies should include (1) proper choices of materials and structural designs, (2) constructing efficient wireless power and data transmission systems, and (3) developing highly-integrated sensing systems.
  • 5.6K
  • 09 Feb 2021
Topic Review
Deep Cryogenic Treatment
Deep cryogenic treatment (DCT) is a type of cryogenic treatment, where a metallic material is subjected to temperatures below -150°C, normally to temperatures of liquid nitrogen (-196 °C). When a material is exposed to DCT as a part of heat treatment, changes in microstructure are induced due to new grain formation, changes in grain size, change in the solubility of atoms, movement of dislocations, alteration of crystal structure, and finally new phase formation. The metallic material's performance and later performance of manufactured components and tools from this specific material are dependent on the selection of proper design, proper material, accuracy with which the tool is made and application of proper heat treatment, including any eventual DCT. Metallic materials are ferrous and non-ferrous metals. In the last years ferrous metals (different grades of steel) and non-ferrous alloys (aluminum, magnesium, titanium, nickel etc.) have been increasingly treated with DCT to alter their properties. DCT treatment has shown to reduce density of defects in crystal structure, increase wear resistance of material, increase hardness, improve toughness, and reduce tensile strength and corrosion resistance. However, some researchers also reported results showing no change in properties (toughness, hardness, corrosion resistance, etc.) or even deterioration when subjected to DCT treatment. This leads to a lack of consistency and reliability of the treatment process, which is needed for successful application in industry. This review provides a synopsis of DCT usage and resulting effects on treated materials used in automotive industry.
  • 5.6K
  • 29 Oct 2020
Topic Review
Hyaluronic Acid
Hyaluronic acid, as a natural linear polysaccharide, has attracted researchers’ attention from its initial detection and isolation from tissues in 1934 until the present day. Due to biocompatibility and a high biodegradation of hyaluronic acid, it finds wide application in bioengineering and biomedicine: from biorevitalizing skin cosmetics and endoprostheses of joint fluid to polymeric scaffolds and wound dressings. However, the main properties of aqueous polysaccharide solutions with different molecular weights are different. Moreover, the therapeutic effect of hyaluronic acid-based preparations directly depends on the molecular weight of the biopolymer. The present entry collects the information about hyaluronic acid and its original properties. Particular emphasis is placed on the structural, physical and physico-chemical properties of hyaluronic acid in water solutions, as well as their degradability.
  • 5.6K
  • 31 Aug 2020
Topic Review
Properties of Phase Change Materials
The main drawback of phase change materials (PCMs) is their low thermal conductivity, which limits the possibilities of a wide range of implementations. Therefore, the researchers, as found in the literature, proposed several methods to improve the thermal conductivity of PCMs, including inserting high thermal conductivity materials in nano-, micro-, and macro-scales, as well as encapsulation of PCMs. However, these inserts impact the other properties of PCMs like latent heat, melting temperature, thermal stability, and cycling stability. 
  • 5.6K
  • 18 Sep 2021
Topic Review
Lobe-Finned Fish
Sarcopterygii (/ˌsɑːrkɒptəˈrɪdʒi.aɪ/; from grc σάρξ (sárx) 'flesh', and πτέρυξ (ptérux) 'wing, fins')—sometimes considered synonymous with Crossopterygii (from grc κροσσός (krossós) 'fringe')—is a taxon (traditionally a class or subclass) of the bony fishes whose members are known as lobe-finned fishes. The group Tetrapoda, a superclass including amphibians, reptiles (including dinosaurs and therefore birds), and mammals, evolved from certain sarcopterygians; under a cladistic view, tetrapods are themselves considered a group within Sarcopterygii. The known extant non-tetrapod sarcopterygians include two species of coelacanths and six species of lungfishes.
  • 5.6K
  • 21 Nov 2022
Topic Review
Allelopathy
Allelopathy is an ecological phenomenon in which organisms interfere with each other. As a management strategy in agricultural systems, allelopathy can be mainly used to control weeds, resist pests, and disease and improve the interaction of soil nutrition and microorganisms. Volatile organic compounds (VOCs) are allelochemicals volatilized from plants and have been widely demonstrated to have different ecological functions.
  • 5.6K
  • 09 Sep 2021
Topic Review
Emulsion Gel and Its Preparation
Emulsion gels are emulsion with a gel network structure and stable mechanical properties. Emulsion gel formation is considered a strategy for oil stabilization and structuring, presenting advantages such as transporting functional components and improving the sensory and physical product properties. 
  • 5.6K
  • 15 Jul 2022
Topic Review
Building Restoration
Building Restoration describes a particular treatment approach and philosophy within the field of architectural conservation and historic preservation. It emphasizes the preservation of structures such as historic sites, houses, monuments, and other significant properties through careful maintenance and upkeep. Restoration aims to create accurate depictions of these locations and protect them against deterioration that could make them inaccessible or unrecognizable in the future.
  • 5.6K
  • 17 Oct 2022
Topic Review
Positive Stereotype
In social psychology, a positive stereotype refers to a subjectively favorable belief held about a social group. Common examples of positive stereotypes are Asians with better math ability, African Americans with greater athletic ability, and women with being more warm and communal. As opposed to negative stereotypes, positive stereotypes represent a "positive" evaluation of a group that typically signals an advantage over another group. As such, positive stereotypes may be considered a form of compliment or praise. However, positive stereotypes can have a positive or negative effect on targets of positive stereotypes. The positive or negative influence of positive stereotypes on targets depends on three factors: (1) how the positive stereotype is stated, (2) who is stating the positive stereotype, (3) in what culture the positive stereotype is presented (e.g., Western contexts vs. East Asian contexts).
  • 5.6K
  • 21 Nov 2022
Topic Review
Irreligion in India
Atheism and agnosticism have a long history in India and flourished within the Śramaṇa movement. Indian religions like Jainism, Hinduism and Buddhism consider atheism to be acceptable. India has produced some notable atheist politicians and social reformers. According to the 2011 Census of India, 99.76% of Indians identified with a religion while 0.24% did not state their religious identity. According to the 2012 WIN-Gallup Global Index of Religion and Atheism report, 81% of Indians were religious, 13% were non-religious, 3% were convinced atheists, and 3% were unsure or did not respond.
  • 5.6K
  • 09 Oct 2022
Topic Review
Nose Ring (Animal)
A nose ring is inserted into the nose of an animal. Nose rings are used to control bulls and occasionally cows, and to help wean young cattle by preventing suckling. Nose rings are used on pigs to discourage rooting. Some nose rings are installed through a pierced hole in the nasal septum or rim of the nose and remain there, while others are temporary tools.
  • 5.6K
  • 03 Nov 2022
Topic Review
Pinophyta
The Pinophyta, also known as Coniferophyta or Coniferae, or commonly as conifers, are a division of vascular land plants containing a single extant class, Pinopsida. They are gymnosperms, cone-bearing seed plants. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, and 629 living species. Although the total number of species is relatively small, conifers are ecologically important. They are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere, but also in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations. The narrow conical shape of northern conifers, and their downward-drooping limbs, help them shed snow. Many of them seasonally alter their biochemistry to make them more resistant to freezing. While tropical rainforests have more biodiversity and turnover, the immense conifer forests of the world represent the largest terrestrial carbon sink. Conifers are of great economic value for softwood lumber and paper production.
  • 5.6K
  • 21 Oct 2022
Topic Review
Russian Financial Crisis (2014–2017)
The financial crisis in Russia in 2014–2015 was the result of the sharp devaluation of the Russian ruble beginning in the second half of 2014. A decline in confidence in the Russian economy caused investors to sell off their Russian assets, which led to a decline in the value of the Russian ruble and sparked fears of a Russian financial crisis. The lack of confidence in the Russian economy stemmed from at least two major sources. The first is the fall in the price of oil in 2014. Crude oil, a major export of Russia, declined in price by nearly 50% between its yearly high in June 2014 and 16 December 2014. The second is the result of international economic sanctions imposed on Russia following Russia's annexation of Crimea and the Russian military intervention in Ukraine. The crisis has affected the Russian economy, both consumers and companies, and regional financial markets, as well as Putin's ambitions regarding the Eurasian Economic Union. The Russian stock market in particular has experienced large declines, with a 30% drop in the RTS Index from the beginning of December through 16 December 2014. During the financial crisis, the economy turned to prevalent state ownership, with 60% of productive assets in the hands of the government. By 2016, the Russian economy rebounded with 0.3% GDP growth and was officially out of the recession. In January 2017, Russia had foreign currency reserves of around $391 billion, an inflation rate of 5.0% and interest rate of 10.0%.
  • 5.6K
  • 09 Nov 2022
Topic Review
Google Home
Google Home is a line of smart speakers developed by Google under the Google Nest brand. The devices enable users to speak voice commands to interact with services through Google Assistant, the company's virtual assistant. Both in-house and third-party services are integrated, allowing users to listen to music, control playback of videos or photos, or receive news updates entirely by voice. Google Nest devices also have integrated support for home automation, letting users control smart home appliances with their voice command. The first device, Google Home, was released in the United States in November 2016; subsequent product releases occurred globally from 2017–2019. Through software updates to Google Nest devices and Google Assistant, additional functionality has been added over time. For example, multiple speakers can be set up for synchronized playback of music. An update in April 2017 brought multi-user support, allowing the device to distinguish between up to six people by voice. In May 2017, Google announced multiple updates, including: hands-free phone calling at no cost in Canada and the United States; proactive reminders ahead of scheduled events; visual responses on mobile devices or Chromecast-enabled televisions; Bluetooth audio streaming; and the ability to add reminders and calendar appointments. The original Google Home speaker released in November 2016 featured a cylindrical shape with colored status LEDs on top. In October 2017, Google announced two additions to the product lineup, the miniature puck-shaped Google Home Mini and a larger Google Home Max. In October 2018, the company released the Google Home Hub, a smart speaker with a 7-inch touchscreen. In May 2019, Google announced that Google Home devices would be rebranded under the Google Nest banner and unveiled a larger smart display called the Google Nest Hub Max.
  • 5.6K
  • 09 Nov 2022
Topic Review
Product Distribution
A product distribution is a probability distribution constructed as the distribution of the product of random variables having two other known distributions. Given two statistically independent random variables X and Y, the distribution of the random variable Z that is formed as the product is a product distribution.
  • 5.6K
  • 11 Nov 2022
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