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A special type of area density is called column density (also columnar mass density or simply column density), denoted ρ A or σ.It is the mass of substance per unit area integrated along a path; [1] It is obtained integrating volumetric density over a column: [2] =.
In physics, a characteristic length is an important dimension that defines the scale of a physical system. Often, such a length is used as an input to a formula in order to predict some characteristics of the system, and it is usually required by the construction of a dimensionless quantity, in the general framework of dimensional analysis and in particular applications such as fluid mechanics.
The contact area depends on the geometry of the contacting bodies, the load, and the material properties. The contact area between the two parallel cylinders is a narrow rectangle. Two, non-parallel cylinders have an elliptical contact area, unless the cylinders are crossed at 90 degrees, in which case they have a circular contact area.
Theoretical chemistry requires quantities from core physics, such as time, volume, temperature, and pressure.But the highly quantitative nature of physical chemistry, in a more specialized way than core physics, uses molar amounts of substance rather than simply counting numbers; this leads to the specialized definitions in this article.
In thermodynamics, a critical point (or critical state) is the end point of a phase 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.
Force per unit oriented surface area Pa L −1 M T −2: order 2 tensor Surface tension: γ: Energy change per unit change in surface area N/m or J/m 2: M T −2: Thermal conductance κ (or) λ: Measure for the ease with which an object conducts heat W/K L 2 M T −3 Θ −1: extensive Thermal conductivity: λ: Measure for the ease with which a ...
The barn is also the unit of area used in nuclear quadrupole resonance and nuclear magnetic resonance to quantify the interaction of a nucleus with an electric field gradient. While the barn never was an SI unit, the SI standards body acknowledged it in the 8th SI Brochure (superseded in 2019) due to its use in particle physics .
Specific surface area (SSA) is a property of solids defined as the total surface area (SA) of a material per unit mass, [1] (with units of m 2 /kg or m 2 /g). Alternatively, it may be defined as SA per solid or bulk volume [ 2 ] [ 3 ] (units of m 2 /m 3 or m −1 ).