Gas constant/?, universal

Here R is the Universal Gas Constant (8.31 Jmol K ) and Q is called the Activation Energy for Creep - it has units of Jmol . Note that the creep rate increases exponentially with temperature (Fig. 17.6, inset). An increase in temperature of 20 C can double the creep rate. 

Q = activation energy for hardening reaction R = universal gas constant T = absolute temperature. 

If the value mw R is the same for all gases, the universal gas constant Ugc is defined and R becomes the specific gas constant. 

Unbalance, response programs, 372 Uninterruptable power supply (UPS), 311 Universal gas constant, 16 University of Virginia, 389 Unloader plug type, 81 plunger type, 81 port type, 81 valve, 81... 

Adsorbate liquid density, g/ml Universal gas constant, J/mol K Temperature, K... 

For many calculations it is required to know the ratio of Cp/C, for a gaseous compound. The well-known expression Cp-C = R (where R is the universal gas constant) holds good only for gases under ideal conditions. When working with situations involving real gases, the relationship between Cp and C, is given as ... 

For example, in the case of dilute solutions, the van t Hoff s equation may be used to piedict the osmotic pressure (jr = CRT) where n is the osmotic pressure of the solution, C is the molar concentration of the solute, ft is the universal gas constant and T is the absolute temperature, Fm dissociating solutes, the concentration is that of the total ions. For example, NaCI dissociates in water into two ions Na" " and Cl . Therefore, the total molar concentration of ions is hvice the molar concentration of NaCI. A useful rule of thumb for predicting osmotic pressure of aqueous solutions is 0,01 psi/ppm of solute (Weber, 1972). 

The appearance of n as the index of jc in Eq. (3.28) needs to be Justified. Combustion in gas turbines usually involves substantial excess air and the molecular weight of the mixed products is little changed from that of the air supplied, since nitrogen is the main component gas for both air and products. Thus the mean gas constant (universal gas constant divided by mean molecular weight) is virtually unchanged by the combustion. It then follows that... 

Here 17 is the apparent viscosity at temperature T, R is the universal gas constant, and A is an empirical constant, called frequency factor for melt flow. The activation energy values for different systems and at different shear rates are summarized in Table 8. It is evident that activation energy for flow increases with filler loading, but it decreases with an increase in shear rate. 

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