Vaporisation function

The chosen forms for the adsorption function, mixing terms, and vaporisation function, respectively, are... 

The flash curve of a petroleum cut is defined as the curve that represents the temperature as a function of the volume fraction of vaporised liquid, the residual liquid being in equilibrium with the total vapor, at constant pressure. 

The vapour enthalpies are calculated from the molar heat capacity functions for the vapour components and the latent heats of vaporisation at standard temperature. The vapour overflow, V, is then obtained from the energy balance as... 

This cycle of vaporisation of the solvent, condensation, extraction, and vacuum-filtration may be repeated any number of times in a solid-fluid serial extractor. The occurrence of an extractive material fluid bed as a result of the flow of boiling hot vapour provides for effective extraction, while pressure filtration provides for short cycle times. This functional principle makes it possible to achieve filtration pressures which are 50-100 times more effective than when using the Soxhlet method, where only the low hydrostatic pressure of the extractive fluid operates. Solid-fluid-vortex extraction according to the proprietary FEXTRA (Feststoff Extraktion) principle is low cost. 

The effect of vapour pressure is most easily visualised when the rates of degradation are plotted as a function of the enthalpy of vaporisation (Fig. 5.14). Plainly the lower the enthalpy of vaporisation (Ai-f ), the more volatile the solvent and the more solvent vapour will enter the bubble. This effectively cushions the collapse of the bubble, so that the movement of solvent is slowed down, lessening the shock wave thereby leading to lower degradation rates. 

In equation (8) the specific Lewis number Le3EM is the ratio of two integral expressions whose substitutions are explained in equations (lb) and (10) respectively. While II(A.) in eq. (lb) contains the undissolved mass fraction G(a) the function K(a) represents the age dependent increase of specific enthalpy in a droplet (9). We assume that the transition from the E.E.s to the L.E. takes place due to the attainment of a transition temperature Slums, which itself is similar to the vaporisation temperature of subcritical liquids. Hence the enthalpy increase is divided by the greatest possible enthalpy gap Aho. 

Aluminium trihydrate (ATH) and magnesium hydroxide (MDH) have been shown to create low smoke levels and much reduced toxic gas emission (245,390). The activity of these materials is a function of the vaporisation of their water of hydration. 

The amount of heat required to convert 1 g. of a pure liquid into saturated vapour at any given temperature (or pressure, since the pressure of saturated vapour is a function only of temperature) is called the latent heat of evaporation (sometimes latent heat of vaporisation), denoted by 4. It is usually understood to apply to evaporation at the normal b.p. at 1 atm. pressure, and it varies rather considerably with temperature. For water ... 

The liquid precursor is transformed into gaseous reactants and the function of this zone is to ensure a sufficient liquid-to-gas-phase transformation. The liquid precursor is vaporised on the outer surface of the preform where the temperature is maintained just above the boiling point of the liquid precursor. In this case the boiling point refers to the temperature at atmospheric pressure for a given hydrocarbon. 

The saturated vapour pressure of a-CdSe was measured in the temperature range 1016 to 1170 K using a gas flow method. Values for the entropy and the enthalpy of formation of a-CdSe at 298.15 were derived using the second law and an estimated heat capacity of a-CdSe. The experimental results were therefore re-evaluated by the review using both the second and the third law, the selected thermodynamic functions of selenium, the data for Cd in [89COX/WAG], the selected heat capacity of a-CdSe, and the selected entropy of a-CdSe in the case of the third law. The vaporisation was assumed to occur according to the reaction a-CdSe Cd(g) + The results were... 

Figure 3 The vapour pressure as a reciprocal function of temperature for water. The slopes of the tangents to the curve are the enthalpies of vaporisation.

Figure 4 Determination of critical temperatiue from the relationship of the enthalpy of vaporisation as a function of temperatm-e.

What differentiates SFC from other separation techniques such as GC and HPLC is the use of this supercritical fluid as the mobile phase. Analytes that cannot be vaporised for analysis by GC and have no functional groups for sensitive detection with HPLC, can often be separated and detected using SFC. In SFC, the sample is carried by a supercritical fluid (typically carbon dioxide) through a separating column where the mixture is divided into unique bands based on the amount of interaction between the analytes and the stationary phase in the column. As these bands leave the column their identities and quantities are determined by a detector. 

---