Search results
Results From The WOW.Com Content Network
The thermal conductivity of a crystal can depend strongly on isotopic purity, assuming other lattice defects are negligible. A notable example is diamond: at a temperature of around 100 K the thermal conductivity increases from 10,000 W·m −1 ·K −1 for natural type IIa diamond (98.9% 12 C), to 41,000 for
Let K 0 is the normal conductivity at one bar (10 5 N/m 2) pressure, K e is its conductivity at special pressure and/or length scale. Let d is a plate distance in meters, P is an air pressure in Pascals (N/m 2), T is temperature Kelvin, C is this Lasance constant 7.6 ⋅ 10 −5 m ⋅ K/N and PP is the product P ⋅ d/T.
Electrical conductivity of water samples is used as an indicator of how salt-free, ion-free, or impurity-free the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as specific conductance, relative to the conductivity of pure water at 25 °C.
In the following table, material data are given with a pressure of 611.7 Pa (equivalent to 0.006117 bar). Up to a temperature of 0.01 °C, the triple point of water, water normally exists as ice, except for supercooled water, for which one data point is tabulated here. At the triple point, ice can exist together with both liquid water and vapor.
(room temperature) (alpha, polycrystalline) calculated from single crystal values 56.2 ... G.W.C. Kaye and T. H. Laby in Tables of physical and chemical constants ...
is the thermal conductivity (W/(K·m)) of the sample; is the thermal resistivity (K·m/W) of the sample; is the cross-sectional area (m 2) perpendicular to the path of heat flow. In terms of the temperature gradient across the sample and heat flux through the sample, the relationship is:
As quoted from various sources in an online version of: David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition.CRC Press. Boca Raton, Florida, 2003; Section 12, Properties of Solids; Thermal and Physical Properties of Pure Metals / Thermal Conductivity of Crystalline Dielectrics / Thermal Conductivity of Metals and Semiconductors as a Function of Temperature
Conductivity sensors are typically calibrated with KCl solutions of known conductivity. Electrolytic conductivity is highly temperature-dependent, but many commercial systems offer automatic temperature correction. Tables of reference conductivities are available for many common solutions. [10]