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Supercritical Liquid–gas Boundaries
Supercritical liquid–gas boundaries are lines in the pressure-temperature (pT) diagram that delimit more liquid-like and more gas-like states of a supercritical fluid. They comprise the Fisher–Widom line, the Widom line, and the Frenkel line. Overview According to textbook knowledge, it is possible to transform a liquid continuously into a gas, without undergoing a phase transition, by heating and compressing strongly enough to go around the critical point. However, different criteria still allow to distinguish liquid-like and more gas-like states of a supercritical fluid. These criteria result in different boundaries in the pT plane. These lines emanate either from the critical point, or from the liquid–vapor boundary (boiling curve) somewhat below the critical point. They do not correspond to first or second order phase transitions, but to weaker singularities. The Fisher–Widom line is the boundary between monotonic and oscillating asymptotics of the pair correla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autocorrelation
Autocorrelation, sometimes known as serial correlation in the discrete time case, measures the correlation of a signal with a delayed copy of itself. Essentially, it quantifies the similarity between observations of a random variable at different points in time. The analysis of autocorrelation is a mathematical tool for identifying repeating patterns or hidden periodicities within a signal obscured by noise. Autocorrelation is widely used in signal processing, time domain and time series analysis to understand the behavior of data over time. Different fields of study define autocorrelation differently, and not all of these definitions are equivalent. In some fields, the term is used interchangeably with autocovariance. Various time series models incorporate autocorrelation, such as unit root processes, trend-stationary processes, autoregressive processes, and moving average processes. Autocorrelation of stochastic processes In statistics, the autocorrelation of a real ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phases Of Matter
In the outline of physical science, physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is a different material, in its own separate phase. (See .) More precisely, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, refractive index, index of refraction, magnetization and chemical composition. The term ''phase'' is sometimes used as a synonym for state of matter, but there can be several Miscibility, immiscible phases of the same state of matter (as where oil and water separate into distinct phases, both in the liquid state). Types of phases Distinct phases may be des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anneke Levelt Sengers
Johanna Maria Henrica (Anneke) Levelt Sengers (4 March 1929 – 28 February 2024) was a Dutch physicist known for her work on critical states of fluids. She retired from the National Institute of Standards and Technology (NIST) in 1994, after a 31 year career there.. In 2005 Levelt Sengers was co-chair (with Dr Manju Sharma) for the InterAcademy Council of the advisory report 'Women for Science' published June 2006. She co-chaired the InterAmerican Network of Academies of Sciences women for science program. Education and career Levelt Sengers was born on 4 March 1929 in Amsterdam, Netherlands. Her father was a chemist and her mother had studied physics. She was the eldest child and had nine siblings. During World War II her father spent time in Buchenwald concentration camp. Levelt Sengers started studying physics at the University of Amsterdam in 1947. She earned her ''candidaats'' (Bachelor of Science) in physics and chemistry from the University of Amsterdam in 1950, a Mast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jan V
Jan V of Zator (; before 1455 – 17 September 1513), was a Duke of Zator during 1468–1474 (with his three brothers as co-rulers), ruler over the western half of Zator from 1474 to 1494 (with his brother Władysław as his co-ruler), and ruler of a reunified duchy from 1494 to his death. He was the third son of Duke Wenceslaus I of Zator by his wife Maria, daughter of Urban Kopczowski, a noblemen from the Duchy of Siewierz. Life At the time of his father's death in 1468, Jan V and his brother Władysław were likely minors, so their older brothers Casimir II and Wenceslaus II assumed the government over the Duchy. The common government of Wenceslaus I's sons lasted until 1474, when was made the formal division of the Duchy in two parts: Jan V, together with Władysław, received the western part of Skawa River. In 1477, Jan V and his brothers signed an arrangement of mutual inheritance, who permitted the eventual reunion of the whole Duchy of Zator. Despite this, Jan V en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mikhail Anisimov
Mikhail Alexeevich Anisimov (Russian: Михаил Алексе́евич Анисимов, born November 2, 1941, Baku, Azerbaijan, USSR) is a Russian and American interdisciplinary scientist. Early life Anisimov received a degree in petroleum engineering from Grozny Petroleum Institute in 1964, a doctorate in physical chemistry from Moscow State University in 1969, and a doctor of science degree in molecular and thermal physics from the Kurchatov Institute of Atomic Energy in Moscow in 1976. Career From 1969 through 1977, Anisimov worked at the U.S.S.R. State Committee for Standards and Product Quality Management (Russian: Госстандарт), where his postdoctoral mentor was Alexander V. Voronel. From 1978 until 1993, Anisimov was a professor and the chairman of the physics department of Gubkin Russian State University of Oil and Gas. In 1994, Anisimov began working in the United States as a professor for both the department of chemical and biomolecular engineering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boltzmann Constant
The Boltzmann constant ( or ) is the proportionality factor that relates the average relative thermal energy of particles in a ideal gas, gas with the thermodynamic temperature of the gas. It occurs in the definitions of the kelvin (K) and the molar gas constant, in Planck's law of black-body radiation and Boltzmann's entropy formula, and is used in calculating Johnson–Nyquist noise, thermal noise in resistors. The Boltzmann constant has Dimensional analysis, dimensions of energy divided by temperature, the same as entropy and heat capacity. It is named after the Austrian scientist Ludwig Boltzmann. As part of the 2019 revision of the SI, the Boltzmann constant is one of the seven "Physical constant, defining constants" that have been defined so as to have exact finite decimal values in SI units. They are used in various combinations to define the seven SI base units. The Boltzmann constant is defined to be exactly joules per kelvin, with the effect of defining the SI unit ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Capacity
Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K). Heat capacity is an extensive property. The corresponding intensive property is the specific heat capacity, found by dividing the heat capacity of an object by its mass. Dividing the heat capacity by the amount of substance in moles yields its molar heat capacity. The volumetric heat capacity measures the heat capacity per volume. In architecture and civil engineering, the heat capacity of a building is often referred to as its '' thermal mass''. Definition Basic definition The heat capacity of an object, denoted by C, is the limit C = \lim_\frac, where \Delta Q is the amount of heat that must be added to the object (of mass ''M'') in order to raise its temperature by \Delta T. The value of this parameter usually varies considerably depending o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latent Heat
Latent heat (also known as latent energy or heat of transformation) is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process—usually a first-order phase transition, like melting or condensation. Latent heat can be understood as hidden energy which is supplied or extracted to change the state of a substance without changing its temperature or pressure. This includes the latent heat of fusion (solid to liquid), the latent heat of vaporization (liquid to gas) and the latent heat of sublimation (solid to gas). The term was introduced around 1762 by Scottish chemist Joseph Black. Black used the term in the context of calorimetry where a heat transfer caused a volume change in a body while its temperature was constant. In contrast to latent heat, sensible heat is energy transferred as heat, with a resultant temperature change in a body. Usage The terms ''sensible heat'' and ''latent heat'' refer to energy transferred between a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercritical Fluid
A supercritical fluid (SCF) is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. It can effuse through porous solids like a gas, overcoming the mass transfer limitations that slow liquid transport through such materials. SCFs are superior to gases in their ability to dissolve materials like liquids or solids. Near the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned". Supercritical fluids occur in the atmospheres of the gas giants Jupiter and Saturn, the terrestrial planet Venus, and probably in those of the ice giants Uranus and Neptune. Supercritical water is found on Earth, such as the water issuing from black smokers, a type of hydrothermal vent. SCFs are used as a substitute for organic solvents in a range of industrial and laborato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pair Correlation Function
In statistical mechanics, the radial distribution function, (or pair correlation function) g(r) in a system of particles (atoms, molecules, colloids, etc.), describes how density varies as a function of distance from a reference particle. If a given particle is taken to be at the origin ''O'', and if \rho = N/V is the average number density of particles, then the local time-averaged density at a distance r from ''O'' is \rho g(r). This simplified definition holds for a homogeneous and isotropic system. A more general case will be considered below. In simplest terms it is a measure of the probability of finding a particle at a distance of r away from a given reference particle, relative to that for an ideal gas. The general algorithm involves determining how many particles are within a distance of r and r+dr away from a particle. This general theme is depicted to the right, where the red particle is our reference particle, and the blue particles are those whose centers are with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Point (thermodynamics)
In thermodynamics, a critical point (or critical state) is the end point of a phase Equilibrium (thermodynamics), equilibrium curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a liquid and its vapor can coexist. At higher temperatures, the gas comes into a supercritical fluid, supercritical phase, and so cannot be liquefied by pressure alone. At the critical point, defined by a ''critical temperature'' ''T''c and a ''critical pressure'' ''p''c, phase (matter), phase boundaries vanish. Other examples include the Upper critical solution temperature, liquid–liquid critical points in mixtures, and the ferromagnet–paramagnet transition (Curie temperature) in the absence of an external magnetic field. Liquid–vapor critical point Overview For simplicity and clarity, the generic notion of ''critical point'' is best introduced by discussing a specific example, the vapor–liquid cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
