Conversion of Temperatures from the

Conversion of Temperatures from the 1948 and 1968 Scales to ITS-90 International System of Units (SI)... 

Tinplate and Solder. Metallurgical studies were performed to determine the effect of irradiation at low temperature on the corrosion resistance of tinplate and on the mechanical properties and microstructure of tinplate and side-seam solder of the tinplate container. The area of major interest was the effect of low-temperature irradiation on the possible conversion of the tin from the beta form to the alpha form. In the case of pure tin, the transition occurs at 18 °C. It was feared that low-temperature irradiation would create dislocations in the crystal lattice of tin and enhance the conversion of tin from the silvery form to a powdery form rendering the tin coating ineffective in protecting the base steel. Tin used for industrial consumption contains trace amounts of soluble impurities of lead and antimony to retard this conversion for several years. 

If we assume that the cooling coil takes up negligible reactor volume, the conversion calculated as a function of temperature from the mole balance is the same as that in Example S-4 [Equation (E8-4.13)]. 

In this equation Av// is the molar change in enthalpy for the conversion of substance from the equilibrium liquid to the equilibrium vapor phase. AVF is the molar change in volume when the substance changes from the liquid to the gas. This equation allows calculation of the enthalpy of vaporization from vapor pressure, and it is the second law method. Measurement of enthalpy of vaporization with a calorimeter is the first law method. The quantities AWH and AVF are functions of temperature along the phase boundary. Equation (1.1) can also be written as,... 

If convergence problems arise in the numerical solutions, especially for hand Calculations, it is often useful to use conversion as the independent variable. Thus, increments of conversion give increments of time from the mass balance, and these give increments of temperature from the heat balance iterations on the evaluations of the rates are also often required. 

Three-wave and four-wave sum-frequency mixing has been used for conversion of radiation from the infrared to the visible, where photographic film can be used and photoelectric detectors offer the advantages of improved sensitivity and increased temporal resolution. Infrared up-conversion has been used for up-conversion of infrared images to the visible and for time-resolved studies of the rotational spectra of molecules formed in explosions, giving information as to the time dependence of the temperature. 

---