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Topic Review
Infrastructure
Infrastructure is the set of fundamental facilities and systems serving a country, city, or other area, including the services and facilities necessary for its economy to function. Infrastructure is composed of public and private physical structures such as roads, railways, bridges, tunnels, water supply, sewers, electrical grids, and telecommunications (including Internet connectivity and broadband speeds). In general, it has also been defined as "the physical components of interrelated systems providing commodities and services essential to enable, sustain, or enhance societal living conditions". There are two general types of ways to view infrastructure: hard and soft. Hard infrastructure refers to the physical networks necessary for the functioning of a modern industry. This includes roads, bridges, railways, etc. Soft infrastructure refers to all the institutions that maintain the economic, health, social, and cultural standards of a country. This includes educational programs, official statistics, parks and recreational facilities, law enforcement agencies, and emergency services. The word infrastructure has been used in French since 1875 and in English since 1887, originally meaning "The installations that form the basis for any operation or system". The word was imported from French, where it was already used for establishing a roadbed of substrate material, required before railroad tracks or constructed pavement could be laid on top of it. The word is a combination of the Latin prefix "infra", meaning "below", as many of these constructions are underground (for example, tunnels, water and gas systems, and railways), and the French word "structure" (derived from the Latin word "structure"). The army use of the term achieved currency in the United States after the formation of NATO in the 1940s, and by 1970 was adopted by urban planners in its modern civilian sense.
  • 1.6K
  • 15 Nov 2022
Topic Review
Flow-Induced Vibration
Flow-induced vibration (FIV) of bluff body structures is a classical bidirectional flow–structure interaction problem, which is linked to various fluid dynamics phenomena (e.g., boundary-layer separation, vortex formation and shedding, hydrodynamic loading on the structures) as well as structure vibrations.
  • 1.6K
  • 01 Dec 2022
Topic Review
Lifshitz Theory of Van Der Waals Force
In condensed matter physics and physical chemistry, the Lifshitz theory of van der Waals forces, sometimes called the macroscopic theory of van der Waals forces, is a method proposed by Evgeny Mikhailovich Lifshitz in 1954 for treating van der Waals forces between bodies which does not assume pairwise additivity of the individual intermolecular forces; that is to say, the theory takes into account the influence of neighboring molecules on the interaction between every pair of molecules located in the two bodies, rather than treating each pair independently.
  • 1.6K
  • 03 Nov 2022
Topic Review
Mie–Gruneisen Equation of State
The Mie–Grüneisen equation of state is a relation between the pressure and the volume of a solid at a given temperature. It is used to determine the pressure in a shock-compressed solid. The Mie–Grüneisen relation is a special form of the Grüneisen model which describes the effect that changing the volume of a crystal lattice has on its vibrational properties. Several variations of the Mie–Grüneisen equation of state are in use. The Grüneisen model can be expressed in the form where V is the volume, p is the pressure, e is the internal energy, and Γ is the Grüneisen parameter which represents the thermal pressure from a set of vibrating atoms. If we assume that Γ is independent of p and e, we can integrate Grüneisen's model to get where p0 and e0 are the pressure and internal energy at a reference state usually assumed to be the state at which the temperature is 0K. In that case p0 and e0 are independent of temperature and the values of these quantities can be estimated from the Hugoniot equations. The Mie–Grüneisen equation of state is a special form of the above equation.
  • 1.6K
  • 22 Nov 2022
Topic Review
Bow Shocks in Astrophysics
Bow shocks form the boundary between a magnetosphere and an ambient (or at least surrounding) magnetized medium. This occurs when the magnetic field of an astrophysical object interacts with the nearby flowing ambient plasma. For example, when the solar wind, flowing with a relative speed of order 400 km/s, encounters the magnetic field of Earth, a bow shape boundary forms. For Earth and other magnetized planets, it is the boundary at which the speed of the stellar wind abruptly drops as a result of its approach to the magnetopause. For stars, this boundary is typically the edge of the astrosphere, where the stellar wind meets the interstellar medium.
  • 1.6K
  • 27 Oct 2022
Topic Review
Characterization of MXene's Terminations
MXene, 2D transition metal carbides, nitrides, and carbonitrides with a unique 2D structure, inspired a series of function applications related to energy storage and conversion, biometrics and sensing, lighting, purification, and separation. Its surface terminations are confined by the adjacent MXene layers, and form the 2D planar space with symmetrical surfaces, which is similar to a 2D nanoreactor that can be utilized and determined MXene’s function. Accurate characterization of MXene surface terminations is the prerequisite for studying the regulatory methods and the influence of properties and performance. Because the surface termination of MXene presents two-dimensional plane distribution and the collision probability of atoms, molecules, electrons, and optical signals is low. MXene prepared by chemical methods has certain impurity content. In addition, most surface terminations do not exist in a stable state, which leads to the difficulty of the accurate characterization of MXene surface terminations. At present, XPS, EDX, XAS and EELS are often used for qualitative and quantitative analysis of MXene surface terminations.
  • 1.6K
  • 09 Nov 2022
Topic Review
Oscillatory Spinning Drop Interfacial Rheology
The oscillatory spinning drop method has been proven recently to be an accurate technique to measure dilational interfacial rheological properties. It is the only available equipment for measuring dilational moduli in low interfacial tension systems, as is the case in applications dealing with surfactant-oil-water three-phase behavior like enhanced oil recovery, crude oil dehydration, or extreme microemulsion solubilization. Different systems can be studied with this method with the lower density phase as the spinning drop, i.e, oil-in-water, microemulsion-in-water, oil-in-microemulsion, including systems with the presence of complex natural surfactants like asphaltene aggregates or particles. The technique allows studying the characteristics and properties of water/oil interfaces, particularly when the oil contains asphaltenes and when surfactants are present. We have found that using the oscillating spinning drop method to measure interfacial rheology properties can help make precise measurements in a reasonable amount of time. This is of significance when systems with long equilibration times, e.g., asphaltene or high molecular weight surfactant-containing systems are measured, or with systems formulated with a demulsifier which is generally associated with optimum formulation and a low interfacial tension.
  • 1.6K
  • 05 Sep 2021
Topic Review
Cosmology
Cosmology (from grc κόσμος (kósmos) 'world', and -λογία (-logía) 'study of') is a branch of physics and metaphysics dealing with the nature of the universe. The term cosmology was first used in English in 1656 in Thomas Blount's Glossographia, and in 1731 taken up in Latin by German philosopher Christian Wolff, in Cosmologia Generalis. Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology. In the science of astronomy it is concerned with the study of the chronology of the universe. Physical cosmology is the study of the observable universe's origin, its large-scale structures and dynamics, and the ultimate fate of the universe, including the laws of science that govern these areas. It is investigated by scientists, such as astronomers and physicists, as well as philosophers, such as metaphysicians, philosophers of physics, and philosophers of space and time. Because of this shared scope with philosophy, theories in physical cosmology may include both scientific and non-scientific propositions, and may depend upon assumptions that cannot be tested. Physical cosmology is a sub-branch of astronomy that is concerned with the Universe as a whole. Modern physical cosmology is dominated by the Big Bang theory, which attempts to bring together observational astronomy and particle physics; more specifically, a standard parameterization of the Big Bang with dark matter and dark energy, known as the Lambda-CDM model. Theoretical astrophysicist David N. Spergel has described cosmology as a "historical science" because "when we look out in space, we look back in time" due to the finite nature of the speed of light.
  • 1.6K
  • 01 Jul 2024
Topic Review
RFID Sensors for IoT
Abstract: Radio-frequency identification (RFID) sensors are one of the fundamental components of the Internet of Things.  Within this framework, chipless RFIDs are a breakthrough technology because, removing the cost associated with the chip, are at the same time printable, passive, low-power and suitable for harsh environments. For this reason, there is a clear motivation and interest to extend the chipless sensing functionality to physical, chemical, structural and environmental parameters. Temperature and humidity sensors, as well as localization, proximity, and structural health prototypes, have already been produced, and many other sensing applications are on the way. In this review, architectural approaches and requirements related to the materials employed for chipless RFID sensing are summarized. The state-of-the-art of many categories of sensors and their applications is reported and an analysis of the current limitations and possible solution strategies are given, together with an overview of expected future developments.
  • 1.6K
  • 29 Oct 2020
Topic Review
Nanobiotechnology
Nanobiotechnology, bionanotechnology, and nanobiology are terms that refer to the intersection of nanotechnology and biology. Given that the subject is one that has only emerged very recently, bionanotechnology and nanobiotechnology serve as blanket terms for various related technologies. This discipline helps to indicate the merger of biological research with various fields of nanotechnology. Concepts that are enhanced through nanobiology include: nanodevices (such as biological machines), nanoparticles, and nanoscale phenomena that occurs within the discipline of nanotechnology. This technical approach to biology allows scientists to imagine and create systems that can be used for biological research. Biologically inspired nanotechnology uses biological systems as the inspirations for technologies not yet created. However, as with nanotechnology and biotechnology, bionanotechnology does have many potential ethical issues associated with it. The most important objectives that are frequently found in nanobiology involve applying nanotools to relevant medical/biological problems and refining these applications. Developing new tools, such as peptoid nanosheets, for medical and biological purposes is another primary objective in nanotechnology. New nanotools are often made by refining the applications of the nanotools that are already being used. The imaging of native biomolecules, biological membranes, and tissues is also a major topic for nanobiology researchers. Other topics concerning nanobiology include the use of cantilever array sensors and the application of nanophotonics for manipulating molecular processes in living cells. Recently, the use of microorganisms to synthesize functional nanoparticles has been of great interest. Microorganisms can change the oxidation state of metals. These microbial processes have opened up new opportunities for us to explore novel applications, for example, the biosynthesis of metal nanomaterials. In contrast to chemical and physical methods, microbial processes for synthesizing nanomaterials can be achieved in aqueous phase under gentle and environmentally benign conditions. This approach has become an attractive focus in current green bionanotechnology research towards sustainable development.
  • 1.6K
  • 11 Oct 2022
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