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Topic Review
Modified Starch-Based Adhesives
Consumer trends towards environmentally friendly products are driving plastics industries to investigate more benign alternatives to petroleum-based polymers. In the case of adhesives, one possibility to achieve sustainable production is to use non-toxic, low-cost starches as biodegradable raw materials for adhesive production. While native starch contains only hydroxyl groups and has limited scope, chemically modified starch shows superior water resistance properties for adhesive applications. Esterified starches, starches with ester substituents, can be feasibly produced and utilized to prepare bio-based adhesives with improved water resistance. Syntheses of esterified starch materials can involve esterification, transesterification, alkylation, acetylation, succinylation, or enzymatic reactions.
  • 4.5K
  • 31 May 2022
Topic Review
Lockheed Martin Compact Fusion Reactor
The Lockheed Martin Compact Fusion Reactor (CFR) is a proposed nuclear fusion reactor project at Lockheed Martin’s Skunk Works. Its high-beta configuration, which implies that the ratio of plasma pressure to magnetic pressure is greater than or equal to 1 (compared to tokamak designs' 0.05), allows a compact fusion reactor (CFR) design and expedited development. The CFR chief designer and technical team lead, Thomas McGuire studied fusion as a source of space propulsion in response to a NASA desire to improve travel times to Mars.
  • 4.5K
  • 17 Oct 2022
Topic Review
Mechanism of the Phytoremediation Technique
A natural ecosystem can become contaminated due to the excessive release of toxic substances by various anthropogenic and natural activities, which necessitates rehabilitation of the environmental contamination. Phytoremediation is an eco-friendly and cost-efficient method of biotechnological mitigation for the remediation of polluted ecosystems and revegetation of contaminated sites.
  • 4.5K
  • 25 Jun 2023
Topic Review
Modular Multilevel Converter Submodules
Voltage-source converter (VSC) HVDC systems based on modular multilevel converters (MMCs) combine the system advantages of fast and independent active and reactive power control, passive network supply, black start capabilities, frequency support and power oscillation damping with power electronics benefits such as scalable design, increased reliability, lower conversion losses and reduced filtering requirements, thus offering a commercially competitive solution. The structure of the SM is an important element of the MMC. This has been the case, where substantial SM topologies have been presented, specifically aimed at extending the functionalities of the MMC, in many cases aligned with niche applications of the converter rather than generic use as a VSC converter.
  • 4.5K
  • 18 Mar 2022
Topic Review
Renewable Energy Status in Azerbaijan
Azerbaijan has a well-developed hydrocarbon industry backed with abundant domestic resources. Oil and gas have played a crucial role in the economic revival of the country since independence was regained back in 1991. The legal foundation of the transition to carbon-zero energy generation was laid in the 1990s with a number of acts mentioning the importance of the shift. The government has an ambitious plan to improve the situation, though an action plan with targeted renewables share in production and consumption is still to be prepared.
  • 4.5K
  • 24 Jan 2022
Topic Review
Power Electronics for Distributed Generation
Power electronics is formed by technologies that, through advanced controls of semiconductor devices, efficiently convert electrical energy for appropriate use in many areas. Distributed generation (DG), mainly renewable energy, is a group of power sources that can be installed in distinct points of the power system or be isolated, such as: wind power, photovoltaic systems, fuel cells, small hydro, and microturbines. Power converters are a crucial technology for the integration of DG into the modern sustainable power system, including microgrids and smart grids structures. They allow correct adaptation, but also enable DG units to fully realize their potential benefits in their wide variety of configurations.
  • 4.5K
  • 23 Mar 2022
Topic Review
Vitamin D in Dairy Products
The term Vitamin D was created in 1922, describing a vitamin able to promote calcium deposition. Vitamin D in nature is available as ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3).
  • 4.5K
  • 05 Nov 2020
Topic Review
Cook Stove
A biomass cook stove is heated by burning wood, charcoal, animal dung or crop residue. Cook stoves are commonly used for cooking and heating food in rural households. Nearly half of the world's population, approximately 3 billion people, use solid fuels such as coal, wood, animal dung, and crop residues for their domestic energy needs. Among those who use indoor cooking stoves, the poorest families living in rural areas most frequently use solid fuels, where it continues to be relied on by up to 90% of households. Households in developing countries consume significantly less energy than those in developed countries; however, over 50% of the energy is for cooking food. The average rural family spends 20% or more of its income purchasing wood or charcoal for cooking. The urban poor also frequently spend a significant portion of their income on the purchase of wood or charcoal. Deforestation and erosion often result from harvesting wood for cooking fuel. The main goal of most improved cooking stoves is to reduce the pressure placed on local forests by reducing the amount of wood the stoves consume, and to reduce the negative health impacts associated with exposure to toxic smoke from traditional stoves.
  • 4.5K
  • 25 Oct 2022
Topic Review
Bitumen Aging and Rejuvenation Chemistry
Bitumen aging and rejuvenation include a series of chemical transformations that the material undergoes and that results in the variation of its physical characteristics.
  • 4.5K
  • 30 Jun 2021
Topic Review
Applications of Tannins
The origin of tannins, their historical evolution, their different types, and their applications are described. Old and established applications are described, as well as the future applications which are being developed at present and that promise to have an industrial impact in the future. The chemistry of some of these applications is discussed where it is essential to understand the tannins and their derivates role. The essential points of each application, their drawbacks, and their chance of industrial application are briefly discussed.
  • 4.5K
  • 29 Jul 2021
Topic Review
Alternatives to Evolution by Natural Selection
Alternatives to evolution by natural selection, also described as non-Darwinian mechanisms of evolution, have been proposed by scholars investigating biology since classical times to explain signs of evolution and the relatedness of different groups of living things. The alternatives in question do not deny that evolutionary changes over time are the origin of the diversity of life, nor deny that the organisms alive today share a common ancestor from the distant past (or ancestors, in some proposals); rather, they propose alternative mechanisms of evolutionary change over time, arguing against mutations acted on by natural selection as the most important driver of evolutionary change. (In most cases, they do not deny that mutations or natural selection occur, or that they play a role in evolutionary change, but instead deny that they are fully sufficient primary causes for the evidence of evolutionary change that is observed in the natural world.) This distinguishes them from certain other kinds of arguments that deny that large scale evolution of any sort has taken place, as in some forms of creationism, which do not propose alternative mechanisms of evolutionary change but instead deny that evolutionary change has taken place at all. Not all forms of creationism deny that evolutionary change takes places; notably, proponents of theistic evolution, such as the biologist Asa Gray, assert that evolutionary change does occur and is responsible for the history of life on Earth, with the proviso that this process has been influenced by a god or gods in some meaningful sense. Where the fact of evolutionary change was accepted but the mechanism proposed by Charles Darwin, natural selection, was denied, explanations of evolution such as Lamarckism, catastrophism, orthogenesis, vitalism, structuralism and mutationism (called saltationism before 1900) were entertained. Different factors motivated people to propose non-Darwinian mechanisms of evolution. Natural selection, with its emphasis on death and competition, did not appeal to some naturalists because they felt it immoral, leaving little room for teleology or the concept of progress in the development of life. Some who came to accept evolution, but disliked natural selection, raised religious objections. Others felt that evolution was an inherently progressive process that natural selection alone was insufficient to explain. Still others felt that nature, including the development of life, followed orderly patterns that natural selection could not explain. By the start of the 20th century, evolution was generally accepted by biologists but natural selection was in eclipse. Many alternative theories were proposed, but biologists were quick to discount theories such as orthogenesis, vitalism and Lamarckism which offered no mechanism for evolution. Mutationism did propose a mechanism, but it was not generally accepted. The modern synthesis a generation later claimed to sweep away all the alternatives to Darwinian evolution, though some have been revived as molecular mechanisms for them have been discovered.
  • 4.5K
  • 09 Oct 2022
Topic Review
Waveguide (Electromagnetism)
In electromagnetics and communications engineering, the term waveguide may refer to any linear structure that conveys electromagnetic waves between its endpoints. However, the original and most common meaning is a hollow metal pipe used to carry radio waves. This type of waveguide is used as a transmission line mostly at microwave frequencies, for such purposes as connecting microwave transmitters and receivers to their antennas, in equipment such as microwave ovens, radar sets, satellite communications, and microwave radio links. A dielectric waveguide employs a solid dielectric rod rather than a hollow pipe. An optical fibre is a dielectric guide designed to work at optical frequencies. Transmission lines such as microstrip, coplanar waveguide, stripline or coaxial cable may also be considered to be waveguides. The electromagnetic waves in a (metal-pipe) waveguide may be imagined as travelling down the guide in a zig-zag path, being repeatedly reflected between opposite walls of the guide. For the particular case of rectangular waveguide, it is possible to base an exact analysis on this view. Propagation in a dielectric waveguide may be viewed in the same way, with the waves confined to the dielectric by total internal reflection at its surface. Some structures, such as non-radiative dielectric waveguides and the Goubau line, use both metal walls and dielectric surfaces to confine the wave.
  • 4.5K
  • 07 Oct 2022
Topic Review
Messaging Apps
Messaging apps (a.k.a. social messaging or chat applications) are apps and platforms that enable instant messaging. Messaging apps are online messaging services used primarily via mobile platforms. Many such apps have developed into broad platforms enabling status updates, chatbots, payments and conversational commerce (e-commerce via chat). They are normally centralised networks run by the servers of the platform's operators, unlike peer-to-peer protocols like XMPP. Some examples of popular messaging apps include WhatsApp, Facebook Messenger, China's WeChat and QQ Messenger, Telegram, Viber, Line, and Snapchat. The popularity of certain apps greatly differ between different countries. Certain apps have emphasis on certain uses - for example Skype focuses on video calling, Slack focuses on messaging and file sharing for work teams, and Snapchat focuses on image messages. Some social networking services offer messaging services as a component of their overall platform, such as Facebook's Facebook Messenger, while others have a direct messaging function as an additional adjunct component of their social networking platforms, like Instagram, Reddit, Tumblr, TikTok, Clubhouse and Twitter, either directly or through chat rooms. Messaging apps are the most widely used smartphone apps, with in 2018 over 1.3 billion monthly users of WhatsApp and Facebook Messenger, 980 million monthly active users of WeChat and 843 million monthly active users of QQ Mobile.
  • 4.5K
  • 09 Nov 2022
Topic Review
Wind Turbine Blade Failures
The wind turbine is a complex structure. Although there is no single approach and there is variability in the commercial designs, a typical WTB is a thin-walled multi-cellular hollow airfoil shaped cross-section. For its manufacture, a number of materials and material systems are used for structural purposes (fibre composites and sandwich composite systems) as well as aesthetic purposes (primers, UV gel coats, paint, etc). The potential causes of wind turbine blade failures can be classified into the following four categories:1. damage from lightning;2. failures due to fatigue;3. leading edge erosion;4. damage from icing.The types of damage caused to wind turbine blades—originating from the above four different sources—along with their significance to the turbine’s performance and secure operation, are detailed in the following sub-sections.
  • 4.5K
  • 11 Oct 2021
Topic Review
Fungicides
Fungicides are considered a vital tool for agriculture, protecting crops against fungal diseases and therefore securing high agricultural productivity. The evolution of technology can provide novel chemical fungicides, such as nanofungicides and chiral fungicides, to address plant resistance development. The extensive use of chemical fungicides leads to a risk for public health, natural waters, and non-target organisms.
  • 4.5K
  • 08 Apr 2022
Topic Review
MINIX
Minix (from "mini-Unix") is a POSIX-compliant (since version 2.0), Unix-like operating system based on a microkernel architecture. Early versions of MINIX were created by Andrew S. Tanenbaum for educational purposes. Starting with MINIX 3, the primary aim of development shifted from education to the creation of a highly reliable and self-healing microkernel OS. MINIX is now developed as open-source software. MINIX was first released in 1987, with its complete source code made available to universities for study in courses and research. It has been free and open-source software since it was re-licensed under the BSD license in April 2000.
  • 4.5K
  • 28 Sep 2022
Topic Review Peer Reviewed
Tsunami Alert Efficiency
“Tsunami Alert Efficiency” is the rapid, accurate and reliable conduct of tsunami warning messaging, from the detection of potential tsunamigenic earthquakes to dissemination to all people under threat, and the successful survival of every person at risk on the basis of prior awareness and preparedness.
  • 4.5K
  • 13 Apr 2022
Topic Review
Nuclear Symmetry Energy
Nuclear symmetry energy is a measure of the energy cost to make nuclear systems more neutron rich. It depends on the density of the system. Information about the density dependence of nuclear symmetry energy has broad ramifications on the mechanisms of supernova explosions, properties of neutron stars and gravitational waves from their mergers. It is also important for understanding properties of nuclei as well as the dynamics and products of their collisions in laboratory experiments. 
  • 4.5K
  • 03 Aug 2021
Topic Review
Insect Pests of Brassica oleracea
The propagation and regeneration of Brassica species has been successful using seeds and different explants like petioles, cotyledons, stems and shoot tips. Shoot regeneration and rooting of Brassica species are successfully obtained from cotyledons and hypocotyl explants. The biological cycle length of Brassica species may either differ slightly or may not differ from one species to another. For instance, the seeds of Brassica oleracea take five days to germinate after sowing at 20–25 °C while the seeds of Brassica campestries take about three to five days to germinate after sowing at 20–25 °C. The most common insect pests of economic importance to Brassica oleracea in African smallholder farmers include Plutella xylostella, Helula undalis, Pieris brassicae, Brevycoryne brassicae, Trichoplusia ni and Myzus persicae. Those insect pests infest cabbages at different stages of growth, causing huge damage and resulting into huge yield losses. The African smallholder farmers use cultural and synthetic pesticides to control those insect pests and minimize infestations. The cultural practices are environmental friendly but are ineffective to control the insect pests. Due to ineffectiveness of cultural practices, African smallholder famers use broad-spectrum synthetic pesticides to effectively control the Brassica species insect pests. The improper and misuse of synthetic pesticides result into insect pests resistance towards the insecticides applied, environmental pollution and human health threats. Insect pests such as Plutella xylostella, Hellula undalis, Brevicoryne brassicae and Myzus persicae have developed resistance to a wide range of pesticides used such as cypermethrin, parathion, decamethrin, quinalphos and lamda-cyhalothrin. Therefore, that calls for search of the alternative products which can effectively be used to control those insect pests in the field.
  • 4.5K
  • 28 Oct 2020
Topic Review
Widow
A widow is a woman whose spouse has died and a widower is a man whose spouse has died. The treatment of widows and widowers around the world varies.
  • 4.5K
  • 25 Oct 2022
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