Processing factors affecting functionality temperature

One of the critical factors affecting growth rates is the gas-phase temperature which can be reached in a CVD method. A comparison of the various CVD methods to each other demonstratesl that typical linear growth rates correlate positively with estimated gas-phase temperatures (Fig. 1), approaching 1 mm h in atmospheric pressure plasma arc-jet CVD with temperatures around 6000 to 7000 K. The partial pressures of various gas species in typical CVD processes have been calculated as a function of... 

Table 10.5 provides performance data regarding the SCWO process. Typical destruction efficiencies (DEs) for a number of compounds are also summarized in Table 10.5, which indicates that the DE could be affected by various parameters such as temperature, pressure, reaction time, oxidant type, and feed concentration. Feed concentrations can slightly increase the DE in supercritical oxidation processes. For SCWO, the oxidation rates appear to be first order and zero order with respect to the reactant and oxygen concentration, respectively. Depending upon reaction conditions and reactants involved, the rate of oxidation varies considerably. Pressure is another factor that can affect the oxidation rate in supercritical water. At a given temperature, pressure variations directly affect the properties of water, and in turn change the reactant concentrations. Furthermore, the properties of water are strong functions of temperature and pressure near its critical point. 

A subtle aspect of stability analysis of freeze-dried products in vials with rubber stoppers is the tendency for water vapor to be transferred from the stopper to the solid during storage. Representative data for residual moisture as a function of time at different temperatures are shown in Figure 11. As expected, the residual moisture level increases more rapidly at higher temperature, but the plateau level is independent of temperature as equilibrium is established between the freeze-dried solid and the stopper. The extent to which this is observed depends on several factors. First, the nature of the rubber stopper formulation affects the diffusivity of water in the rubber. Second, the processing of the stopper can affect the level of residual moisture present. It is not uncommon for extended drying of the stopper to be necessary to minimize residual moisture. Finally, the mass of the freeze-dried solid determines the extent to which the percent residual moisture is affected by water vapor transfer from the stopper, where large cakes may be relatively unaffected by the small amount of water vapor that is... 

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