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Topic Review
CO2 Activation on Catalyst Surfaces
Utilizing CO2 as a sustainable carbon source to form valuable products requires activating it by active sites on catalyst surfaces. These active sites are usually in or below the nanometer scale. Some metals and metal oxides in this scale dimension can catalyze the CO2 transformation reactions. Herein, CO2 activation on metal-based catalyst surfaces and how their structures impact the activation process are highlighted.
  • 4.5K
  • 13 Dec 2021
Topic Review
Sociology of Space
The sociology of space is a sub-discipline of sociology that mostly borrows from theories developed within the discipline of geography, including the sub fields of human geography, economic geography, and feminist geography. The "sociology" of space examines the social and material constitution of spaces. It is concerned with understanding the social practices, institutional forces, and material complexity of how humans and spaces interact. The sociology of space is an inter-disciplinary area of study, drawing on various theoretical traditions including Marxism, postcolonialism, and Science and Technology Studies, and overlaps and encompasses theorists with various academic disciplines such as geography and architecture. Edward T. Hall developed the study of Proxemics which concentrates on the empirical analysis of space in psychology.
  • 4.5K
  • 03 Nov 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
Papaverine and Its Mechanism of Action
Papaverine has been proven to be a high-value opioid alkaloid in the field of therapeutics either in solitude or in combination with other metabolites/molecules. Pharmacological research has revealed that papaverine demonstrates a variety of biological activities, including activity against erectile dysfunction, postoperative vasospasms, and pulmonary vasoconstriction, as well as antiviral, cardioprotective, anti-inflammatory, anticancer, neuroprotective, and gestational actions.
  • 4.5K
  • 07 Apr 2023
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
Building Domain-Specific Search Engines
With advances in machine learning, knowledge discovery systems have become very complicated to set up, requiring extensive tuning and programming effort. Democratizing such technology so that non-technical domain experts can avail themselves of these advances in an interactive and personalized way is an important problem. myDIG is a highly modular, open source pipeline-construction system that is specifically geared towards investigative users (e.g., law enforcement) with no programming abilities. The myDIG system allows users both to build a knowledge graph of entities, relationships, and attributes for illicit domains from a raw HTML corpus and also to set up a personalized search interface for analyzing the structured knowledge. Both qualitative and quantitative data from five case studies involving investigative experts from illicit domains, such as securities fraud and illegal firearms sales, have been used to illustrate the potential of myDIG.
  • 4.5K
  • 10 Feb 2021
Topic Review Video
Direct Carbon Fuel Cells
Most fuel cells invariably use gaseous or liquid fuels. A fuel cell technology that has attracted attention only recently, the direct carbon fuel cell (DCFC) uses solid fuel (carbon) and converts the chemical energy in the carbon to electricity through its direct participation in the fuel cell reactions and electrochemical oxidation. The fuel use can be almost 100% compared with about 85% for most other fuel cells. The electrical efficiency is expected to be above 70% - almost twice those of current generation coal-fired plants leading to 50% reduction in greenhouse gas emissions. The amount of CO2 for storage/sequestration is also halved. Moreover, the exit gas is almost pure carbon dioxide stream, requiring no or minimal gas separation and processing for sequestration. Therefore, the energy and cost penalties to capture the CO2 will be significantly less than for other technologies. However, the technology is at an early stage of development requiring many complex challenges to be overcome, related to materials and corrosion, fuel delivery mechanism, and system development, before it can be commercialized. Section 19.4 of a recent book by the author gives an overview of this technology focusing on its main issues (Sequeira, 2019.). Two of the main DCFCs, the direct carbon molten carbonate fuel cell (DC-MCFC) and the direct carbon solid oxide fuel cell (DC-SOFC) are described in this topic review. 
  • 4.5K
  • 04 Aug 2021
Topic Review
Adaptation
The term “adaptation” is currently used in the climate field. It originated from natural science in the field of population biology and evolutionary ecology. It originally referred to the general characteristics that ensure the survival and reproduction of organic individuals in living environments. The definition of “adaptation” has many attributes, including the two most important points. First is the spatial scale of adaptation, which depends on who is responsible. Second is the nature of adaptive behavior, whether it is spontaneous or conscious or it is planned or prescriptive. The former is usually short-term and tactical adaptation, which is directly related to specific climate change. The latter is more strategic, long-term, and proactive and is usually formulated by government departments and used as part of policy adaptation measures. The adaptation to climate change in the literature is sometimes divergent at the temporal and spatial scales. Short-term adaptation is more of a reaction, and higher-scale adaptation is considered an expected adaptation through policies, projects, and recent plans and actions.
  • 4.5K
  • 15 Nov 2021
Topic Review
Storm Botnet
The Storm botnet or Storm worm botnet (also known as Dorf botnet and Ecard malware) was a remotely controlled network of "zombie" computers (or "botnet") that had been linked by the Storm Worm, a Trojan horse spread through e-mail spam. At its height in September 2007, the Storm botnet was running on anywhere from 1 million to 50 million computer systems, and accounted for 8% of all malware on Microsoft Windows computers. It was first identified around January 2007, having been distributed by email with subjects such as "230 dead as storm batters Europe," giving it its well-known name. The botnet began to decline in late 2007, and by mid-2008 had been reduced to infecting about 85,000 computers, far less than it had infected a year earlier. As of December 2012, the original creators of Storm have not been found. The Storm botnet has displayed defensive behaviors that indicated that its controllers were actively protecting the botnet against attempts at tracking and disabling it, by specifically attacking the online operations of some security vendors and researchers who had attempted to investigate it. Security expert Joe Stewart revealed that in late 2007, the operators of the botnet began to further decentralize their operations, in possible plans to sell portions of the Storm botnet to other operators. It was reportedly powerful enough to force entire countries off the Internet, and was estimated to be capable of executing more instructions per second than some of the world's top supercomputers. The United States Federal Bureau of Investigation considered the botnet a major risk to increased bank fraud, identity theft, and other cybercrimes.
  • 4.5K
  • 11 Oct 2022
Topic Review
Snow Line
The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow will lie all year.
  • 4.5K
  • 16 Dec 2022
Topic Review
Microgrids Configurations and Topologies
Microgrids have been proposed as a solution to the growing deterioration of traditional electrical power systems and the energy transition towards renewable sources. During the design of an microgrid (MG), the components and physical arrangement must be considered to achieve a proper transition between the different modes of operation. The connection of the loads, the microgenerators, and the storage elements, require rigorous analysis to obtain the operation and the desired efficiency by the network operator and the user. The way to interconnect all the elements of the network is known as MG topology.
  • 4.5K
  • 19 Apr 2022
Topic Review
C3 to CAM Photosynthesis Transition
Global climate change and population growth are persistently posing threats to natural resources (e.g., freshwater) and agricultural production. Crassulacean acid metabolism (CAM) evolved from C3 photosynthesis as an adaptive form of photosynthesis in hot and arid regions. It features the nocturnal opening of stomata for CO2 assimilation, diurnal closure of stomata for water conservation, and high water-use efficiency.
  • 4.5K
  • 08 Sep 2023
Topic Review
MXene
The MXenes are a kind of 2D metal carbide/nitride with an alternative atomic arrangement of Mn+1Xn (M = transition metals; X = C, N; n = 1, 2, 3, 4).
  • 4.5K
  • 23 Feb 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
Land Use and Land Cover Mapping
The volume of collected or archived geospatial data for land use and land cover (LULC) mapping including remotely sensed satellite imagery and auxiliary geospatial datasets is increasing. Innovative machine learning, deep learning algorithms, and cutting-edge cloud computing have also been developed. While new opportunities are provided by these geospatial big data and advanced computer technologies for LULC mapping, challenges also emerge for LULC mapping from using these geospatial big data.
  • 4.5K
  • 17 Oct 2022
Topic Review
Tea EGCG and Coffee CGA
Tea and coffee are consumed worldwide and epidemiological and clinical studies have shown their health beneficial effects, including anti-cancer effects. Epigallocatechin gallate (EGCG) and chlorogenic acid (CGA) are the major components of green tea polyphenols and coffee polyphenols, respectively, and believed to be responsible for most of these effects. Although a large number of cell-based and animal experiments have provided convincing evidence to support the anti-cancer effects of green tea, coffee, EGCG, and CGA, human studies are still controversial and some studies have suggested even an increased risk for certain types of cancers such as esophageal and gynecological cancers with green tea consumption and bladder and lung cancers with coffee consumption. 
  • 4.5K
  • 20 Oct 2020
Topic Review
Pakistan’s Heritage Management
Improving archaeology policies means fostering search and exploration of ancient sites, promoting protection and preservation actions of architectural remains, and management of cultural heritage.
  • 4.5K
  • 19 Apr 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
Kepler (Spacecraft)
Kepler is a space observatory launched by NASA to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched on March 7, 2009, into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. Designed to survey a portion of our region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitors the brightness of approx 150,000 main sequence stars in a fixed field of view. These data are transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Kepler is part of NASA's Discovery Program of relatively low-cost, focused primary science missions. The telescope's construction and initial operation were managed by NASA's Jet Propulsion Laboratory, with Ball Aerospace responsible for developing the Kepler flight system. The Ames Research Center is responsible for the ground system development, mission operations since December 2009, and scientific data analysis. The initial planned lifetime was 3.5 years, but greater-than-expected noise in the data, from both the stars and the spacecraft, meant additional time was needed to fulfill all mission goals. Initially, in 2012, the mission was expected to be extended until 2016, but on July 14, 2012, one of the spacecraft's four reaction wheels used for pointing the spacecraft stopped turning, and completing the mission would only be possible if all other reaction wheels remained reliable. Then, on May 11, 2013, a second reaction wheel failed, disabling the collection of science data and threatening the continuation of the mission. On August 15, 2013, NASA announced that they had given up trying to fix the two failed reaction wheels. This meant the current mission needed to be modified, but it did not necessarily mean the end of planet hunting. NASA had asked the space science community to propose alternative mission plans "potentially including an exoplanet search, using the remaining two good reaction wheels and thrusters". On November 18, 2013, the K2 "Second Light" proposal was reported. This would include utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs. On May 16, 2014, NASA announced the approval of the K2 extension. (As of January 2015), Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 star systems, along with a further 3,199 unconfirmed planet candidates.[upper-alpha 2] Four planets have been confirmed through Kepler's K2 mission. In November 2013, astronomers estimated, based on Kepler space mission data, that there could be as many as 40 billion rocky, Earth-size exoplanets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. It is estimated that 11 billion of these planets may be orbiting Sun-like stars. The nearest such planet may be 3.7 parsecs (12 ly) away, according to the scientists. On January 6, 2015, NASA announced the 1,000th confirmed exoplanet discovered by the Kepler Space Telescope. Four of the newly confirmed exoplanets were found to orbit within habitable zones of their related stars: three of the four, Kepler-438b, Kepler-442b and Kepler-452b, are almost Earth-size and likely rocky; the fourth, Kepler-440b, is a super-Earth. On May 10, 2016, NASA verified 1,284 new exoplanets found by Kepler, the single largest finding of planets to date. Kepler data has also helped scientists observe and understand supernovae; measurements were collected every half-hour so the light curves were especially useful for studying these types of astronomical events.
  • 4.5K
  • 20 Oct 2022
Topic Review
Theoretical Foundations of Smart Village
The smart village is defined as a village in which the efforts of inhabitants and institutions are supported and integrated with information technology systems and innovation to benefit local communities. The idea of the smart village is most often associated with objectives such as improvements in welfare, energy savings, a low-emission economy, a reduction in inequalities between urban and rural areas, and an improvement in economic conditions.
  • 4.5K
  • 25 Jul 2022
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