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Topic Review
Metamaterials
Metamaterials are amongst the advanced materials made up initially with metal structures. However, there is a huge ongoing work on dielectric metasurfaces and metamaterials with the aim of replacing metal structures with dielectric ones in order to reduce the electromagnetic losses.
  • 3.0K
  • 31 Mar 2022
Topic Review
Substrate Integrated Waveguide
A Substrate integrated waveguide (SIW) (also known as post-wall waveguide or laminated waveguide) is a synthetic rectangular electromagnetic waveguide formed in a dielectric substrate by densely arraying metallized posts or via-holes which connect the upper and lower metal plates of the substrate. The waveguide can be easily fabricated with low-cost mass-production using through-hole techniques where the post walls consists of via fences. SIW is known to have similar guided wave and mode characteristics to conventional rectangular waveguide with equivalent guide wavelength. Since the emergence of new communication technologies in the 1990s, there has been an increasing need for high-performance millimeter-wave systems. These need to be reliable, low-cost, compact, and compatible with high-frequencies. Unfortunately, above 10 GHz, the well known microstrip and coplanar lines technologies cannot be used because they have high insertion and radiation losses at these frequencies. The rectangular waveguide topology can overcome these issues as it offers an excellent immunity against radiation losses and presents low insertion losses. But in their classical form, rectangular waveguide is not compatible with the miniaturization required by modern applications. The concept of SIW was developed in the early 2000s by Ke Wu to reconcile those requirements. The authors presented a platform for integrating all the components of a microwave circuit inside a single substrate, with a rectangular cross-section. Using a single substrate guarantees a limited volume and a simplicity of manufacture, while the rectangular cross-section of the line provides the advantages of the waveguide topology in terms of losses.
  • 3.0K
  • 27 Sep 2022
Topic Review
Cosmopolitodus Hastalis
Cosmopolitodus hastalis, the broad-tooth mako (other common names include the extinct giant mako and broad-tooth white shark), is an extinct mackerel shark that lived from the Miocene epoch to the Pliocene epoch. Its teeth can reach lengths up to 3.5 in (7.5 cm) and are found worldwide. It is believed to be an ancestor to the great white shark, a fact supported by the transitional species Carcharodon hubbelli, and most likely would have been one of the major predators in its ecosystem; preying upon small whales and other mammals.
  • 3.0K
  • 28 Oct 2022
Topic Review
Heterogeneous Electroreduction of CO2 on Copper-Based Catalysts
Facing greenhouse effects and the rapid exhaustion of fossil fuel, CO2 electrochemical reduction presents a promising method of environmental protection and energy transformation. Low onset potential, large current density, high faradaic efficiency (FE), and long-time stability are required for industrial production, due to economic costs and energy consumption. Copper is one of the few metals that can reduce CO2 to hydrocarbons and alcohols with decent efficiency, and copper-based catalysts have received much attention. The uniqueness of Cu as a CO2RR electrocatalyst is explained by the fact that it is the only metal that has negative adsorption energy for *CO and positive adsorption energy for *H.
  • 3.0K
  • 18 Aug 2022
Topic Review
Command Responsibility
Command responsibility (also superior responsibility, the Yamashita standard, and the Medina standard) is the legal doctrine of hierarchical accountability for war crimes. The legal doctrine of command responsibility was codified in the Hague Conventions of 1899 and 1907, and is partly based upon the American Lieber Code, a manual of war for the Union forces, authorised by President A. Lincoln in 1863, two years into the course of the U.S. civil war. The legal doctrine of command responsibility was first applied by the German Supreme Court, in the Leipzig War Crimes Trials (1921), which included the trial of Imperial German Army officer Emil Müller for war crimes committed during the First World War (1914–1918). The Yamashita standard derived from the incorporation to the U.S. Code of the legal doctrine of command responsibility, as codified in the two Hague Conventions. That legal precedent, decided by the U.S. Supreme Court, allowed the U.S. prosecution of the war-crimes case against General Tomoyuki Yamashita, for the atrocities committed by his soldiers in the Philippine Islands, in the Pacific Theatre (1941–1945) of the Second World War. A U.S. military tribunal charged Yamashita with "unlawfully disregarding, and failing to discharge, his duty as a commander to control the acts of members of his command, by permitting them to commit war crimes." The Medina standard expanded the U.S. Code to include the criminal liability of U.S. military officers for the war crimes committed by their subordinates, as are military officers of an enemy power, e.g. the war-crimes trial of Gen. Yamashita in 1945. The Medina standard originated from the charging, prosecution, and court-martial of U.S. Army Captain Ernest Medina in 1971, for not exercising his superior responsibility as company commander, by not acting to halt the commission of a war crime by his soldiers — the My Lai Massacre (16 March 1968) during the Vietnam War (1945–1975).
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  • 31 Oct 2022
Topic Review
Yellow Supergiant Star
A yellow supergiant (YSG) is a star, generally of spectral type F or G, having a supergiant luminosity class (e.g. Ia or Ib). They are stars that have evolved away from the main sequence, expanding and becoming more luminous. Yellow supergiants are smaller than red supergiants; naked eye examples include Polaris. Many of them are variable stars, mostly pulsating Cepheids such as δ Cephei itself.
  • 3.0K
  • 03 Nov 2022
Topic Review
Perezhivanie and Its Application
Perezhivanie is a concept that was originally defined by Vygotsky, but it did not become a part of educational theory until recently. Today the concept has been revived, and it is now used as a way to include emotional aspects into education and educational research. The concept also provides a rationale for describing and forming personalised learning.
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  • 17 Jan 2022
Topic Review
Single Event Upset
A single event upset (SEU) is a change of state caused by one single ionizing particle (ions, electrons, photons...) striking a sensitive node in a micro-electronic device, such as in a microprocessor, semiconductor memory, or power transistors. The state change is a result of the free charge created by ionization in or close to an important node of a logic element (e.g. memory "bit"). The error in device output or operation caused as a result of the strike is called an SEU or a soft error. The SEU itself is not considered permanently damaging to the transistor's or circuits' functionality unlike the case of single event latchup (SEL), single event gate rupture (SEGR), or single event burnout (SEB). These are all examples of a general class of radiation effects in electronic devices called single event effects (SEE).
  • 3.0K
  • 24 Oct 2022
Topic Review
Genome Editing in Bacteria
Genome editing in bacteria encompasses a wide array of laborious and multi-step methods such as suicide plasmids. The discovery and applications of clustered regularly interspaced short palindromic repeats (CRISPR)-Cas based technologies have revolutionized genome editing in eukaryotic organisms due to its simplicity and programmability. 
  • 3.0K
  • 26 May 2021
Topic Review
Authenticity
Authenticity is a concept of personality in the fields of psychology, existential psychotherapy, existentialist philosophy, and aesthetics. In existentialism, authenticity is the degree to which a person's actions are congruent with his or her values and desires, despite external pressures to social conformity. The conscious Self comes to terms with the condition of Geworfenheit, of having been thrown into an absurd world (without values and without meaning) not of his or her own making, thereby encountering external forces and influences different from and other than the Self. In human relations, a person’s lack of authenticity is considered bad faith in dealing with other people and with one's self; thus, authenticity is in the instruction of the Oracle of Delphi: “Know thyself.” Concerning authenticity in art, the philosophers Jean Paul Sartre and Theodor Adorno held opposing views and opinions about jazz, a genre of American music; Sartre said that jazz is authentic and Adorno said that jazz is inauthentic. The musical subcultures of punk rock and Heavy metal require artistic authenticity, lest the community consider an artist to be a poseur for lacking authenticity (creative, musical, personal); likewise, artistic authenticity is integral to the genres of House music, Grunge, and Garage rock, Hip-hop, Techno, and show tunes. In every human activity, personal authenticity extends the instruction of the Oracle of Delphi: “Don’t merely know thyself — be thyself.”
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  • 08 Oct 2022
Topic Review
Dynamic Positioning
Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyrocompasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include, but are not limited to, ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels, cable layer ships and cruise ships. The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster. This allows operations at sea where mooring or anchoring is not feasible due to deep water, congestion on the sea bottom (pipelines, templates) or other problems. Dynamic positioning may either be absolute in that the position is locked to a fixed point over the bottom, or relative to a moving object like another ship or an underwater vehicle. One may also position the ship at a favorable angle towards wind, waves and current, called weathervaning. Dynamic positioning is used by much of the offshore oil industry, for example in the North Sea, Persian Gulf, Gulf of Mexico, West Africa, and off the coast of Brazil . There are currently more than 1800 DP ships.
  • 3.0K
  • 04 Nov 2022
Topic Review
Plug-In Electric Vehicles in the United Kingdom
The adoption of plug-in electric vehicles in the United Kingdom is actively supported by the British government through the plug-in car and van grants schemes and other incentives. Around 455,000 light-duty plug-in electric vehicles had been registered in the UK up until February 2021, consisting of about 215,000 all-electric vehicles and 240,000 plug-in hybrids. Until 2019, the UK had the second largest European stock of light-duty plug-in vehicles in use after Norway.
  • 3.0K
  • 11 Nov 2022
Topic Review
Mode (Computer Interface)
In user interface design, a mode is a distinct setting within a computer program or any physical machine interface, in which the same user input will produce perceived results different to those that it would in other settings. The best-known modal interface components are probably the Caps lock and Insert keys on the standard computer keyboard, both of which put the user's typing into a different mode after being pressed, then return it to the regular mode after being re-pressed. An interface that uses no modes is known as a modeless interface. Modeless interfaces avoid mode errors by making it impossible for the user to commit them.
  • 3.0K
  • 16 Nov 2022
Topic Review
Application of Graphene in Electronic Devices
Graphene achieved a peerless level among nanomaterials in terms of its application in electronic devices, owing to its fascinating and novel properties. Its large surface area and high electrical conductivity combine to create high-power batteries. In addition, because of its high optical transmittance, low sheet resistance, and the possibility of transferring it onto plastic substrates, graphene is also employed as a replacement for indium tin oxide (ITO) in making electrodes for touch screens. Moreover, it was observed that graphene enhances the performance of transparent flexible electronic modules due to its higher mobility, minimal light absorbance, and superior mechanical properties. Graphene is even considered a potential substitute for the post-Si electronics era, where a high-performance graphene-based field-effect transistor (GFET) can be fabricated to detect the lethal SARS-CoV-2. Hence, graphene incorporation in electronic devices can facilitate immense device structure/performance advancements.
  • 3.0K
  • 18 Oct 2022
Topic Review
Electrodermal Activity Data Collection
The electrodermal activity (EDA) signal is an electrical manifestation of the sympathetic innervation of the sweat glands. EDA has a history in psychophysiological (including emotional or cognitive stress) research since 1879, but it was not until recent years that researchers began using EDA for pathophysiological applications like the assessment of fatigue, pain, sleepiness, exercise recovery, diagnosis of epilepsy, neuropathies, depression, and so forth. The advent of new devices and applications for EDA has increased the development of novel signal processing techniques, creating a growing pool of measures derived mathematically from the EDA. For many years, simply computing the mean of EDA values over a period was used to assess arousal. Much later, researchers found that EDA contains information not only in the slow changes (tonic component) that the mean value represents, but also in the rapid or phasic changes of the signal. The techniques that have ensued have intended to provide a more sophisticated analysis of EDA, beyond the traditional tonic/phasic decomposition of the signal. With many researchers from the social sciences, engineering, medicine, and other areas recently working with EDA, it is timely to summarize and review the recent developments and provide an updated and synthesized framework for all researchers interested in incorporating EDA into their research.
  • 3.0K
  • 30 Oct 2020
Topic Review
Drone Architecture for Crowd Monitoring and Analysis
Crowd monitoring and analysis is an important evolving applications of unmanned aerial vehicle or drones. From preventing stampede in high concentration crowds to estimating crowd density and to surveilling crowd movements, crowd monitoring and analysis have long been employed in the past by authorities and regulatory bodies to tackle challenges posed by large crowds.
  • 3.0K
  • 03 Mar 2022
Topic Review
1860 Oxford Evolution Debate
The 1860 Oxford evolution debate took place at the Oxford University Museum in Oxford, England , on 30 June 1860, seven months after the publication of Charles Darwin's On the Origin of Species. Several prominent British scientists and philosophers participated, including Thomas Henry Huxley, Bishop Samuel Wilberforce, Benjamin Brodie, Joseph Dalton Hooker and Robert FitzRoy. The debate is best remembered today for a heated exchange in which Wilberforce supposedly asked Huxley whether it was through his grandfather or his grandmother that he claimed his descent from a monkey. Huxley is said to have replied that he would not be ashamed to have a monkey for his ancestor, but he would be ashamed to be connected with a man who used his great gifts to obscure the truth. One eyewitness suggests that Wilberforce's question to Huxley may have been "whether, in the vast shaky state of the law of development, as laid down by Darwin, any one can be so enamoured of this so-called law, or hypothesis, as to go into jubilation for his great great grandfather having been an ape or a gorilla?", whereas another suggests he may have said that "it was of little consequence to himself whether or not his grandfather might be called a monkey or not." The encounter is often known as the Huxley–Wilberforce debate or the Wilberforce–Huxley debate, although this description is somewhat misleading. Rather than being a formal debate between the two, it was actually an animated discussion that occurred after the presentation of a paper by John William Draper of New York University, on the intellectual development of Europe with relation to Darwin's theory (one of a number of scientific papers presented during the week as part of the British Association's annual meeting). Although Huxley and Wilberforce were not the only participants in the discussion, they were reported to be the two dominant parties. No verbatim account of the debate exists, and there is considerable uncertainty regarding what Huxley and Wilberforce actually said.
  • 3.0K
  • 18 Oct 2022
Topic Review
Explicit Formulae (L-function)
In mathematics, the explicit formulae for L-functions are relations between sums over the complex number zeroes of an L-function and sums over prime powers, introduced by (Riemann 1859) for the Riemann zeta function. Such explicit formulae have been applied also to questions on bounding the discriminant of an algebraic number field, and the conductor of a number field.
  • 3.0K
  • 01 Nov 2022
Topic Review
Kinesthetic Learning
Kinesthetic learning (American English), kinaesthetic learning (British English), or tactile learning is a learning style in which learning takes place by the students carrying out physical activities, rather than listening to a lecture or watching demonstrations. As cited by Favre (2009), Dunn and Dunn define kinesthetic learners as students who require whole-body movement to process new and difficult information.
  • 3.0K
  • 11 Oct 2022
Topic Review
Thia-Michael Reaction
While the Michael addition has been employed for more than 130 years for the synthesis of a vast diversity of compounds, the reversibility of this reaction when heteronucleophiles are involved has been generally less considered. First applied to medicinal chemistry, the reversible character of the hetero-Michael reactions has been explored for the synthesis of Covalent Adaptable Networks (CANs), in particular the thia-Michael reaction and more recently the aza-Michael reaction. In these cross-linked networks, exchange reactions take place between two Michael adducts by successive dissociation and association steps. In order to understand and precisely control the exchange in these CANs, it is necessary to get an insight into the critical parameters influencing the Michael addition and the dissociation rates of Michael adducts by reconsidering previous studies on these matters. 
  • 3.0K
  • 28 Nov 2022
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