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Thermodynamics. Thermal expansion is the tendency of matter to increase in length, area, or volume, changing its size and density, in response to an increase in temperature (usually excluding phase transitions ). [ 1] Substances usually contract with decreasing temperature ( thermal contraction ), with rare exceptions within limited temperature ...
Thermally modified wood. Beechwood processed at different temperatures. From left to right: 200 °C, 190 °C, untreated. Thermally modified wood is engineered wood that has been modified by a controlled pyrolysis process of wood being heated to (> 180 °C) in an oxygen free atmosphere.
Thermal diffusivity. In heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. [ 1] It is a measure of the rate of heat transfer inside a material. It has units of m 2 /s. Thermal diffusivity is usually denoted by lowercase alpha ( α ), but a, h, κ ( kappa ...
Thermal energy stored in the mass is then released back into the interior during the night. It is essential that it be used in conjunction with the standard principles of passive solar design. Any form of thermal mass can be used. A concrete slab foundation either left exposed or covered with conductive materials, e.g. tiles, is one easy solution.
Thermal insulation. Thermal insulation is the reduction of heat transfer (i.e., the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes ...
Conduction heat flux q k for ideal gas is derived with the gas kinetic theory or the Boltzmann transport equations, and the thermal conductivity is =, -, where u f 2 1/2 is the RMS (root mean square) thermal velocity (3k B T/m from the MB distribution function, m: atomic mass) and τ f-f is the relaxation time (or intercollision time period ...
Thermal stress. In mechanics and thermodynamics, thermal stress is mechanical stress created by any change in temperature of a material. These stresses can lead to fracturing or plastic deformation depending on the other variables of heating, which include material types and constraints. [1] Temperature gradients, thermal expansion or ...
The thermal boundary layer thickness is customarily defined as the point in the boundary layer, , where the temperature reaches 99% of the free stream value : such that = 0.99. at a position along the wall. In a real fluid, this quantity can be estimated by measuring the temperature profile at a position along the wall.