Search results
Results from the WOW.Com Content Network
A polytropic process is a thermodynamic process that obeys the relation: = where p is the pressure, V is volume, n is the polytropic index, and C is a constant. The polytropic process equation describes expansion and compression processes which include heat transfer.
The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg−1 · °C−1 for tooth (enamel) to 4.2 kJ · kg−1 · °C−1 for eye (sclera). [13]
The normalized density as a function of scale length for a wide range of polytropic indices. In astrophysics, a polytrope refers to a solution of the Lane–Emden equation in which the pressure depends upon the density in the form = (+) / = + /, where P is pressure, ρ is density and K is a constant of proportionality. [1]
Substituting from the ideal gas equation gives finally: = where n = number of moles of gas in the thermodynamic system under consideration and R = universal gas constant. On a per mole basis, the expression for difference in molar heat capacities becomes simply R for ideal gases as follows:
Specific heat capacity often varies with temperature, and is different for each state of matter. Liquid water has one of the highest specific heat capacities among common substances, about 4184 J⋅kg −1 ⋅K −1 at 20 °C; but that of ice, just below 0 °C, is only 2093 J⋅kg −1 ⋅K −1.
Since the process is isochoric, dV = 0, the previous equation now gives = Using the definition of specific heat capacity at constant volume, c v = ( dQ / dT )/ m , where m is the mass of the gas, we get d Q = m c v d T {\displaystyle dQ=mc_{\mathrm {v} }\,dT}
For example, the expression for the heat capacity at constant pressure is: = which is the partial derivative of the enthalpy with respect to temperature while holding pressure constant. We may write this equation as:
In thermal physics and thermodynamics, the heat capacity ratio, also known as the adiabatic index, the ratio of specific heats, or Laplace's coefficient, is the ratio of the heat capacity at constant pressure (C P) to heat capacity at constant volume (C V).