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In terms of relative permeability, the magnetic susceptibility is χ m = μ r − 1. {\displaystyle \chi _{m}=\mu _{r}-1.} The number χ m is a dimensionless quantity , sometimes called volumetric or bulk susceptibility, to distinguish it from χ p ( magnetic mass or specific susceptibility) and χ M ( molar or molar mass susceptibility).
In physics and engineering, permeation (also called imbuing) is the penetration of a permeate (a fluid such as a liquid, gas, or vapor) through a solid.It is directly related to the concentration gradient of the permeate, a material's intrinsic permeability, and the materials' mass diffusivity. [1]
To account for the internal energy of the open system, this requires energy transfer terms in addition to those for heat and work. It also leads to the idea of the chemical potential. A wall selectively permeable only to a pure substance can put the system in diffusive contact with a reservoir of that pure substance in the surroundings.
For example, for a wall permeable only to heat, the rates of diffusion of internal energy as heat between the two systems are equal and opposite. An adiabatic wall between the two systems is 'permeable' only to energy transferred as work; at mechanical equilibrium the rates of transfer of energy as work between them are equal and opposite.
These terms refer to the quality that the permeability value in question is an intensive property of the medium, not a spatial average of a heterogeneous block of material equation 2.28 [clarification needed] [further explanation needed]; and that it is a function of the material structure only (and not of the fluid).
In the natural sciences an open system is one whose border is permeable to both energy and mass. [2] By contrast, a closed system is permeable to energy but not to matter. The definition of an open system assumes that there are supplies of energy that cannot be depleted; in practice, this energy is supplied from some source in the surrounding ...
Permeable Press, an American publishing company Topics referred to by the same term This disambiguation page lists articles associated with the title Permeability .
In thermodynamics, a diathermal wall between two thermodynamic systems allows heat transfer but does not allow transfer of matter across it.. The diathermal wall is important because, in thermodynamics, it is customary to assume a priori, for a closed system, the physical existence of transfer of energy across a wall that is impermeable to matter but is not adiabatic, transfer which is called ...