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Micro CT of porous medium: Pores of the porous medium shown as purple color and impermeable porous matrix shown as green-yellow color. 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.
Connected porosity is more easily measured through the volume of gas or liquid that can flow into the rock, whereas fluids cannot access unconnected pores. Porosity is the ratio of pore volume to its total volume. Porosity is controlled by: rock type, pore distribution, cementation, diagenetic history and composition. Porosity is not controlled ...
At the microscopic and macroscopic levels, porous media can be classified. At the microscopic scale, the structure is represented statistically by the distribution of pore sizes, the degree of pore interconnection and orientation, the proportion of dead pores, etc. [4] The macroscopic technique makes use of bulk properties that have been averaged at scales far bigger than pore size.
Pore size variation also compartmentalizes the soil pore space such that many microbial and faunal organisms are not in direct competition with one another, which may explain not only the large number of species present, but the fact that functionally redundant organisms (organisms with the same ecological niche) can co-exist within the same soil.
The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size, filter thickness and biological activity).
An illustration of the effects of sorting on the overall porosity of a porous media. The black shapes represent solids, the blue represents pore spaces. "Porosity and Permeability." World of Earth Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner.
The distribution of pores, fluid pressure, and stress in the solid matrix gives rise to the viscoelastic behavior of the bulk. [7] Porous media whose pore space is filled with a single fluid phase, typically a liquid, is considered to be saturated. Porous media whose pore space is only partially fluid is a fluid is known to be unsaturated.
It is widely used to measure minimum, maximum (or first bubble point) and mean flow pore sizes, and pore size distribution in membranes [1] nonwovens, paper, filtration and ultrafiltration media, hollow fibers, [2] ceramics, etc. In capillary flow porometry an inert gas is used to displace a liquid, which is in the pores. The pressure required ...