List of Symbols. 
| a | geometrical dimension, [m] | 
| A | geometrical dimension, [m] | 
| b | geometrical dimension, [m] | 
| B | Biot number, usually hL/k. | 
| cp | specific heat, [J/kg/K] | 
| dsi | differential area element on surface Si, [m2] | 
|  | differential volume element, [m3] | 
| erf (z) | error function,  | 
| f | boundary function, units [K] for type 1 boundary, otherwise units [W/m2] | 
| F(r) | initial temperature distribution, [K] | 
| g | volume energy generation, ![$[W/m^{3}orJ/m^{3}/\sec ]$](img3.gif) | 
| G | Green's function | 
| h | heat transfer coefficient, [W/m2/K] | 
| H(t) | Heaviside unit step function | 
| i,j | indices | 
| J | Joule, unit of energy | 
| k | thermal conductivity [W/m/K] | 
| kg | kilogram, unit of mass | 
| K | Kelvin, unit of absolute temperature | 
| L | geometrical dimension, sometimes body thickness, [m] | 
| m | fin effect parameter, [m-1]; also meter, unit of length | 
| ni | outward unit normal vector on surface Si | 
| P | propagator, function related to the GF | 
| q | heat flux, [W/m2] | 
| r | radial coordinate, [m] | 
|  | position vector, [m] | 
| R | numbering system designation for radial cylindrical coordinate | 
| RS | numbering system designation for radial spherical coordinate | 
| Si | body surface | 
| sec | second, unit of time | 
| t | time, [sec] | 
| T | temperature, [K] | 
| x,y,z | Cartesian coordinates | 
| X, Y, Z | numbering system designations for Cartesian coordinates | 
| W | Watt, a unit of power, equal to one Joule per second. | 
Greek symbols
|  | thermal diffusivity ![$[m^{2}/\sec ]$](img6.gif) | 
|  | eigen value | 
|  | Dirac delta function | 
|  | Laplacian, spatial derivative in Heat equation | 
|  | small parameter | 
|  | density [kg/m3] | 
|  | time at which the heat pulse is released, [sec] | 
|  | azimuthal angle, cylindrical and spherical coordinates | 
|  | polar angle, spherical coordinates |