Regulators on Dec. 24, 2013, approved a price hike of 3 cents for a first-class stamp, bringing the charge to 49 cents a letter in an effort to help the Postal Service recover from severe mail decreases brought on after the 2008 economic downturn.
C-value â Thermal Conductance. Thermal conductance is the time rate of steady state heat flow through a unit area of a material or construction induced by a unit temperature difference between the body surfaces, in W/m2âK. C-value, hence, is the reciprocal of the R-value and can be expressed as Equation (3).
R-value â Thermal Resistance. Thermal resistance is the temperature difference, at steady state, between two defined surfaces of a material or construction that induces a unit heat flow rate through a unit area, Kâm2/W. According to this definition and Equation 1, Equation 2, therefore, can be obtained.