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Pore Structure
Pore structure is a common term employed to characterize the porosity, pore size, pore size distribution, and pore morphology (such as pore shape, surface roughness, and tortuosity of pore channels) of a porous medium. Pores are the openings in the surfaces impermeable porous matrix which gases, liquids, or even foreign microscopic particles can inhabit them. The pore structure and fluid flow in porous media are intimately related. With micronanoscale pore radii, complex connectivity, and significant heterogeneity, the complexity of the pore structure affects the hydraulic conductivity and retention capacity of these fluids. The intrinsic permeability is the attribute primarily influenced by the pore structure, and the fundamental physical factors governing fluid flow and distribution are the grain surface-to-volume ratio and grain shape. The idea that the pore space is made up of a network of channels through which fluid can flow is particularly helpful. Pore openings are t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open 4D Micro CT
Open or OPEN may refer to: Music * Open (band), Australian pop/rock band * The Open (band), English indie rock band * ''Open'' (Blues Image album), 1969 * ''Open'' (Gotthard album), 1999 * ''Open'' (Cowboy Junkies album), 2001 * ''Open'' (YFriday album), 2001 * ''Open'' (Shaznay Lewis album), 2004 * ''Open'' (Jon Anderson EP), 2011 * ''Open'' (Stick Men album), 2012 * ''Open'' (The Necks album), 2013 * ''Open'', a 1967 album by Julie Driscoll, Brian Auger and the Trinity * ''Open'', a 1979 album by Steve Hillage * "Open" (Queensrÿche song) * "Open" (Mýa song) * "Open", the first song on The Cure album ''Wish'' Literature * ''Open'' (Mexican magazine), a lifestyle Mexican publication * ''Open'' (Indian magazine), an Indian weekly English language magazine featuring current affairs * ''OPEN'' (North Dakota magazine), an out-of-print magazine that was printed in the Fargo, North Dakota area of the U.S. * Open: An Autobiography, Andre Agassi's 2009 memoir Comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraction
A fraction (from la, fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, three-quarters. A ''common'', ''vulgar'', or ''simple'' fraction (examples: \tfrac and \tfrac) consists of a numerator, displayed above a line (or before a slash like ), and a non-zero denominator, displayed below (or after) that line. Numerators and denominators are also used in fractions that are not ''common'', including compound fractions, complex fractions, and mixed numerals. In positive common fractions, the numerator and denominator are natural numbers. The numerator represents a number of equal parts, and the denominator indicates how many of those parts make up a unit or a whole. The denominator cannot be zero, because zero parts can never make up a whole. For example, in the fraction , the numerator 3 indicates that the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Roughness
Surface roughness, often shortened to roughness, is a component of surface finish (surface texture). It is quantified by the deviations in the direction of the normal vector of a real surface from its ideal form. If these deviations are large, the surface is rough; if they are small, the surface is smooth. In surface metrology, roughness is typically considered to be the high-frequency, short-wavelength component of a measured surface. However, in practice it is often necessary to know both the amplitude and frequency to ensure that a surface is fit for a purpose. Roughness plays an important role in determining how a real object will interact with its environment. In tribology, rough surfaces usually wear more quickly and have higher friction coefficients than smooth surfaces. Roughness is often a good predictor of the performance of a mechanical component, since irregularities on the surface may form nucleation sites for cracks or corrosion. On the other hand, roughness may pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Conductivity
The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity. For instance, metals typically have high thermal conductivity and are very efficient at conducting heat, while the opposite is true for insulating materials like Rockwool or Styrofoam. Correspondingly, materials of high thermal conductivity are widely used in heat sink applications, and materials of low thermal conductivity are used as thermal insulation. The reciprocal of thermal conductivity is called thermal resistivity. The defining equation for thermal conductivity is \mathbf = - k \nabla T, where \mathbf is the heat flux, k is the thermal conductivity, and \nabla T is the temperature gradient. This is known as Fourier's Law for heat conduction. Although commonly expressed as a scalar, the most general form of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusivity
Diffusivity is a rate of diffusion, a measure of the rate at which particles or heat or fluids can spread. It is measured differently for different mediums. Diffusivity may refer to: *Thermal diffusivity, diffusivity of heat *Diffusivity of mass: ** Mass diffusivity, molecular diffusivity (often called "diffusion coefficient") ** Eddy diffusion, eddy diffusivity * Kinematic viscosity, characterising momentum diffusivity *Magnetic diffusivity Dimensions and Units Diffusivity has dimensions of length2 / time, or m2/s in SI units The International System of Units, known by the international abbreviation SI in all languages and sometimes Pleonasm#Acronyms and initialisms, pleonastically as the SI system, is the modern form of the metric system and the world's most wid ... and cm2/s in CGS units. References Former disambiguation pages converted to set index articles {{SIA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geoscience
Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres, namely biosphere, hydrosphere, atmosphere, and geosphere. Earth science can be considered to be a branch of planetary science, but with a much older history. Earth science encompasses four main branches of study, the lithosphere, the hydrosphere, the atmosphere, and the biosphere, each of which is further broken down into more specialized fields. There are both reductionist and holistic approaches to Earth sciences. It is also the study of Earth and its neighbors in space. Some Earth scientists use their knowledge of the planet to locate and develop energy and mineral resources. Others study the impact of human activity on Earth's environment, and design methods to protect the planet. Some use their knowledge about Earth processes such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Transfer
Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, Convection (heat transfer), thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species (mass transfer in the form of advection), either cold or hot, to achieve heat transfer. While these mechanisms have distinct characteristics, they often occur simultaneously in the same system. Heat conduction, also called diffusion, is the direct microscopic exchanges of kinetic energy of particles (such as molecules) or quasiparticles (such as lattice waves) through the boundary between two systems. When an object is at a different temperature from another body or its surroundings, heat flows so that the body and the surroundings reach the same temperature, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter (rho). The SI unit of electrical resistivity is the ohm-meter (Ω⋅m). For example, if a solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is , then the resistivity of the material is . Electrical conductivity or specific conductance is the reciprocal of electrical resistivity. It represents a material's ability to conduct electric current. It is commonly signified by the Greek letter ( sigma), but ( kappa) (especially in electrical engineering) and ( gamma) are sometimes used. The SI unit of electrical conductivity is siemens per metre (S/m). Resistivity and conductivity are inte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percolation
Percolation (from Latin ''percolare'', "to filter" or "trickle through"), in physics, chemistry and materials science, refers to the movement and filtering of fluids through porous materials. It is described by Darcy's law. Broader applications have since been developed that cover connectivity of many systems modeled as lattices or graphs, analogous to connectivity of lattice components in the filtration problem that modulates capacity for percolation. Background During the last decades, percolation theory, the mathematical study of percolation, has brought new understanding and techniques to a broad range of topics in physics, materials science, complex networks, epidemiology, and other fields. For example, in geology, percolation refers to filtration of water through soil and permeable rocks. The water flows to recharge the groundwater in the water table and aquifers. In places where infiltration basins or septic drain fields are planned to dispose of substantial amounts of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tortuosity
Tortuosity is widely used as a critical parameter to predict transport properties of porous media, such as rocks and soils. But unlike other standard microstructural properties, the concept of tortuosity is vague with multiple definitions and various evaluation methods introduced in different contexts. Hydraulic, electrical, diffusional, and thermal tortuosities are defined to describe different transport processes in porous media, while geometrical tortuosity is introduced to characterize the morphological property of porous microstructures. Tortuosity in 2-D Subjective estimation (sometimes aided by optometric grading scales) is often used. The simplest mathematical method to estimate tortuosity is the arc-chord ratio: the ratio of the length of the curve (''C'') to the distance between its ends (''L''): :\tau = \frac Arc-chord ratio equals 1 for a straight line and is infinite for a circle. Another method, proposed in 1999, is to estimate the tortuosity as the integral of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tortuosity Via Geodesic Distance Calculation
Tortuosity is widely used as a critical parameter to predict transport properties of porous media, such as rocks and soils. But unlike other standard microstructural properties, the concept of tortuosity is vague with multiple definitions and various evaluation methods introduced in different contexts. Hydraulic, electrical, diffusional, and thermal tortuosities are defined to describe different transport processes in porous media, while geometrical tortuosity is introduced to characterize the morphological property of porous microstructures. Tortuosity in 2-D Subjective estimation (sometimes aided by optometric grading scales) is often used. The simplest mathematical method to estimate tortuosity is the arc-chord ratio: the ratio of the length of the curve (''C'') to the distance between its ends (''L''): :\tau = \frac Arc-chord ratio equals 1 for a straight line and is infinite for a circle. Another method, proposed in 1999, is to estimate the tortuosity as the integral o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Sensor
A pressure sensor is a device for pressure measurement of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually acts as a transducer; it generates a signal as a function of the pressure imposed. For the purposes of this article, such a signal is electrical. Pressure sensors are used for control and monitoring in thousands of everyday applications. Pressure sensors can also be used to indirectly measure other variables such as fluid/gas flow, speed, water level, and altitude. Pressure sensors can alternatively be called pressure transducers, pressure transmitters, pressure senders, pressure indicators, piezometers and manometers, among other names. Pressure sensors can vary drastically in technology, design, performance, application suitability and cost. A conservative estimate would be that there may be over 50 technologies and at least 300 companies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
