Notation

			$a$    geometrical dimension, $[m]$
$A$    geometrical dimension, $[m]$
$b$    geometrical dimension, $[m]$
$B$    Biot number, usually $hL/k.$
$c_{p}$    specific heat, $[J/kg/K]$
$ds_{i}$   differential area element on surface $S_{i}$, $[m^{2}]$
$dv^{\prime }$   differential volume element, $[m^{3}]$
erfc$(z)$   error function, $erfc(z)=2/\sqrt{\pi }\int_{z}^{\infty}e^{-t^{2}}dt$
$f$   boundary function, units $[K]$for type 1 boundary, otherwise units $[W/m^{2}]$
$F(r)$   initial temperature distribution, $[K]$
$g$   volume energy generation, $[W/m^{3}orJ/m^{3}/\sec ]$
$G$   Green's function
$h$   heat transfer coefficient, $[W/m^{2}/K]$
$H(t)$   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
$n_{i}$   outward unit normal vector on surface S$_{i}$
$P$   propagator, function related to the GF
$q$   heat flux, $[W/m^{2}]$
$r$   radial coordinate, $[m]$
$\overrightarrow{\mathbf{r}}$   position vector, $[m]$
R    numbering system designation for radial cylindrical coordinate
RS    numbering system designation for radial spherical coordinate
$S_{i}$   body surface
$s$   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
$\alpha$   thermal diffusivity $[m^{2}/\sec ]$
$\beta$   eigen value
$\delta (x)$   Dirac delta function
$\nabla ^{2}$   Laplacian, spatial derivative in Heat equation
$\epsilon$   small parameter
$\rho$   density $[kg/m^{3}]$
$\tau$   time at which the heat pulse is released, $[sec]$
$\phi$   azimuthal angle, cylindrical and spherical coordinates
$\theta$   polar angle, spherical coordinates