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  2. Temperature coefficient - Wikipedia

    en.wikipedia.org/wiki/Temperature_coefficient

    For a property R that changes when the temperature changes by dT, the temperature coefficient α is defined by the following equation: d R R = α d T {\displaystyle {\frac {dR}{R}}=\alpha \,dT} Here α has the dimension of an inverse temperature and can be expressed e.g. in 1/K or K −1 .

  3. Conversion of scales of temperature - Wikipedia

    en.wikipedia.org/wiki/Conversion_of_scales_of...

    This is a collection of temperature conversion formulas and comparisons among eight different temperature scales, several of which have long been obsolete.. Temperatures on scales that either do not share a numeric zero or are nonlinearly related cannot correctly be mathematically equated (related using the symbol =), and thus temperatures on different scales are more correctly described as ...

  4. Table of thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Table_of_thermodynamic...

    Quantity (common name/s) (Common) symbol/s Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer

  5. Thermal expansion - Wikipedia

    en.wikipedia.org/wiki/Thermal_expansion

    A number of materials contract on heating within certain temperature ranges; this is usually called negative thermal expansion, rather than "thermal contraction".For example, the coefficient of thermal expansion of water drops to zero as it is cooled to 3.983 °C (39.169 °F) and then becomes negative below this temperature; this means that water has a maximum density at this temperature, and ...

  6. NTU method - Wikipedia

    en.wikipedia.org/wiki/NTU_Method

    The other fluid would change temperature more slowly along the heat exchanger length. The method, at this point, is concerned only with the fluid undergoing the maximum temperature change. The effectiveness of the heat exchanger ( ϵ {\displaystyle \epsilon } ) , is the ratio between the actual heat transfer rate and the maximum possible heat ...

  7. Newton's law of cooling - Wikipedia

    en.wikipedia.org/wiki/Newton's_law_of_cooling

    When stated in terms of temperature differences, Newton's law (with several further simplifying assumptions, such as a low Biot number and a temperature-independent heat capacity) results in a simple differential equation expressing temperature-difference as a function of time. The solution to that equation describes an exponential decrease of ...

  8. Heat equation - Wikipedia

    en.wikipedia.org/wiki/Heat_equation

    The temperature approaches a linear function because that is the stable solution of the equation: wherever temperature has a nonzero second spatial derivative, the time derivative is nonzero as well. The heat equation implies that peaks ( local maxima ) of u {\displaystyle u} will be gradually eroded down, while depressions ( local minima ...

  9. Thermodynamic equations - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_equations

    Entropy cannot be measured directly. The change in entropy with respect to pressure at a constant temperature is the same as the negative change in specific volume with respect to temperature at a constant pressure, for a simple compressible system. Maxwell relations in thermodynamics are often used to derive thermodynamic relations. [2]