Topic Review
Soundscape Design of Indoor Environments
A growing number of soundscape studies involving audiovisual factors have been conducted; however, their bimodal and interactive effects on indoor soundscape evaluations have not yet been thoroughly reviewed. The overarching goal of this systematic review was to develop the framework for designing sustainable indoor soundscapes by focusing on audiovisual factors and relations. A search for individual studies was conducted through three databases and search engines: Scopus, Web of Science, and PubMed. Based on the qualitative reviews of the selected thirty papers, a framework of indoor soundscape evaluation concerning visual and audiovisual indicators was proposed. Overall, the greenery factor was the most important visual variable, followed by the water features and moderating noise annoyance perceived by occupants in given indoor environments. The presence of visual information and sound-source visibility would moderate perceived noise annoyance and influence other audio-related perceptions. Furthermore, sound sources would impact multiple perceptual responses (audio, visual, cognitive, and emotional perceptions) related to the overall soundscape experiences when certain visual factors are interactively involved. The proposed framework highlights the potential use of the bimodality and interactivity of the audiovisual factors for designing indoor sound environments in more effective ways.
  • 1.2K
  • 31 Mar 2021
Topic Review
4D Scanning Transmission Electron Microscopy
4D scanning transmission electron microscopy (4D STEM) is a subset of scanning transmission electron microscopy (STEM) which utilizes a pixelated electron detector to capture a convergent beam electron diffraction (CBED) pattern at each scan location. This technique captures a 2 dimensional reciprocal space image associated with each scan point as the beam rasters across a 2 dimensional region in real space, hence the name 4D STEM. Its development was enabled by evolution in STEM detectors and improvements computational power. The technique has applications in visual diffraction imaging, phase orientation and strain mapping, phase contrast analysis, among others. The name 4D STEM is common in literature, however it is known by other names: 4D STEM EELS, ND STEM (N- since the number of dimensions could be higher than 4), position resolved diffraction (PRD), spatial resolved diffractometry, momentum-resolved STEM, "nanobeam precision electron diffraction", scanning electron nano diffraction, nanobeam electron diffraction, or pixelated STEM.
  • 1.2K
  • 11 Oct 2022
Topic Review
1769 Transit of Venus Observed from Tahiti
On June 3, 1769, British navigator Captain James Cook, British naturalist Joseph Banks, British astronomer Charles Green and Swedish naturalist Daniel Solander recorded the transit of Venus on the island of Tahiti during Cook's first voyage around the world. During a transit, Venus appears as a small black disc travelling across the Sun. This unusual astronomical phenomenon takes place in a pattern that repeats itself every 243 years. It includes two transits that are eight years apart, separated by breaks of 121.5 and 105.5 years. These men, along with a crew of scientists, were commissioned by the Royal Society of London for the primary purpose of viewing the transit of Venus. Not only would their findings help expand scientific knowledge, it would help with navigation by accurately calculating the observer's longitude. At this time, longitude was difficult to determine and not always precise. A "secret" mission that followed the transit included the exploration of the South Pacific to find the legendary Terra Australis Incognita or "unknown land of the South."
  • 1.2K
  • 30 Sep 2022
Topic Review
Single-Element 2D Materials beyond Graphene
Thanks to their remarkable mechanical, thermal, electrical, magnetic, and optical properties, 2D materials promise to revolutionize electronics. The unique properties of graphene-like 2D materials give them the potential to create completely new types of devices for functional electronics, nanophotonics, and quantum technologies. 
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  • 05 Jul 2022
Topic Review
Korean Taekwondo Athletes
This study aimed to present a standard and normal distribution of Taekwondo athletes’ physical characteristics and physical fitness profiles using a systematic review. A systematic search was conducted using four Korean databases (Research Information Sharing Service, National Digital Science Library, DBpia, and Korean Studies Information Service System). From 2010 to 2020, we reviewed 838 papers on Taekwondo athletes’ physical characteristics and physical fitness factors (e.g., body composition, muscle strength, muscular endurance, flexibility, cardiorespiratory fitness, power, agility, balance, speed, and reaction time).
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  • 29 Sep 2021
Topic Review
Asterism
An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. The patterns of stars seen in asterisms are not necessarily a product of any physical association between the stars, but are rather the result of the particular perspectives of their observations. For example the Summer Triangle is a purely observational physically unrelated group of stars, but the stars of Orion's Belt are all members of the Orion OB1 association and five of the seven stars of the Big Dipper are members of the Ursa Major Moving Group. Physical associations, such as the Hyades or Pleiades, can be asterisms in their own right and part of other asterism at the same time.
  • 1.2K
  • 29 Nov 2022
Topic Review
Field
In physics, a field is a physical quantity, represented by a scalar, vector, or tensor, that has a value for each point in space and time. For example, on a weather map, the surface temperature is described by assigning a number to each point on the map; the temperature can be considered at a certain point in time or over some interval of time, to study the dynamics of temperature change. A surface wind map, assigning an arrow to each point on a map that describes the wind speed and direction at that point, is an example of a vector field, i.e. a 1-dimensional (rank-1) tensor field. Field theories, mathematical descriptions of how field values change in space and time, are ubiquitous in physics. For instance, the electric field is another rank-1 tensor field, while electrodynamics can be formulated in terms of two interacting vector fields at each point in spacetime, or as a single-rank 2-tensor field. In the modern framework of the quantum theory of fields, even without referring to a test particle, a field occupies space, contains energy, and its presence precludes a classical "true vacuum". This has led physicists to consider electromagnetic fields to be a physical entity, making the field concept a supporting paradigm of the edifice of modern physics. "The fact that the electromagnetic field can possess momentum and energy makes it very real ... a particle makes a field, and a field acts on another particle, and the field has such familiar properties as energy content and momentum, just as particles can have." In practice, the strength of most fields diminishes with distance, eventually becoming undetectable. For instance the strength of many relevant classical fields, such as the gravitational field in Newton's theory of gravity or the electrostatic field in classical electromagnetism, is inversely proportional to the square of the distance from the source (i.e., they follow Gauss's law). A field can be classified as a scalar field, a vector field, a spinor field or a tensor field according to whether the represented physical quantity is a scalar, a vector, a spinor, or a tensor, respectively. A field has a consistent tensorial character wherever it is defined: i.e. a field cannot be a scalar field somewhere and a vector field somewhere else. For example, the Newtonian gravitational field is a vector field: specifying its value at a point in spacetime requires three numbers, the components of the gravitational field vector at that point. Moreover, within each category (scalar, vector, tensor), a field can be either a classical field or a quantum field, depending on whether it is characterized by numbers or quantum operators respectively. In this theory an equivalent representation of field is a field particle, for instance a boson.
  • 1.2K
  • 11 Oct 2022
Topic Review
The Resistive Barrier Discharge
Plasma generated by the resistive barrier discharge has been used to efficiently inactivate pathogenic microorganisms and to destroy cancer cells. These biomedical applications of low temperature plasma are of great interest because in recent times bacteria developed increased resistance to antibiotics and because present cancer therapies often are accompanied by serious side effects. Low temperature plasma, such the one generated by the resistive barrier discharge, is a technology that can help overcome these healthcare challenges.
  • 1.2K
  • 08 Feb 2021
Topic Review
J/Psi Meson
The J/ψ (J/psi) meson /ˈdʒeɪ ˈsaɪ ˈmiːzɒn/ or psion is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium". The J/ψ is the most common form of charmonium, due to its spin of 1 and its low rest mass. The J/ψ has a rest mass of 3.0969 GeV/c2, just above that of the ηc (2.9836 GeV/c2), and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected. Its discovery was made independently by two research groups, one at the Stanford Linear Accelerator Center, headed by Burton Richter, and one at the Brookhaven National Laboratory, headed by Samuel Ting of MIT. They discovered they had actually found the same particle, and both announced their discoveries on 11 November 1974. The importance of this discovery is highlighted by the fact that the subsequent, rapid changes in high-energy physics at the time have become collectively known as the "November Revolution". Richter and Ting were awarded the 1976 Nobel Prize in Physics.
  • 1.2K
  • 09 Nov 2022
Topic Review
Space and Upper Atmosphere Research Commission
Established in its modern form on 16 September 1961 by an executive order of President of Pakistan, it is headquartered in Karachi, Sindh Province of Pakistan. Part of the Strategic Plans Division (SPD) of Pakistan Armed Forces, which is currently headquartered at the Chakalala Military District under the control of the Pakistan Air Force ; the space programmes recorded number of pioneering accomplishments in space flight during the initial years of its establishment. The country's first satellite, Badr-I, was built by the SUPARCO and launched from the Xichang Satellite Launch Center, China on July 16, 1990. However, during the meantime, the space programme suffered many setbacks, difficulties, and problems that partly slowed the progress of the space programme. The bureaucratic influence and politicization further lagged the space programme and many projects were cancelled by the superior authorities. Over the years, SUPARCO expanded and it now has several installations all over the country. It has multi-lateral and bilateral international agreements. SUPARCO has been quite dormant in recent years and also have failed to make any breakthroughs. SUPARCO's science and research is mainly focused and concentrated on understanding of the Solar system, Space weather, astrophysics, astronomical observation, climatic studies, space and telemedicine, remote sensing and the Earth observation.
  • 1.2K
  • 02 Nov 2022
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