CONTRASTE model, dissolved gases

In the laboratory experiments, the oil extracted by cyclic steaming from the formation model was fully de-gassed so that there was no dissolved gas drive. By contrast, during cyclic steaming of oil wells in the Zybza field, the dissolved gas drive provided one of the major sources... 

In contrast w DCLS, the ptire spectra in the indirect approach are not measured direcfly, but are estimated from mixture spectra. One reason for using ICLS is that a is not possible to physically separate die components (e.g., when one cd the components of interest is a gas and future prediction samples are mixtures of the gas dissolved in a liquid). Indirect CLS is also used when the model assumptions do not hold if the pure component is run neat. By preparing mixtures, it is possible to dilute a strongly absorbing component so that the modd assumptions hold. 

Model System Theory. In contrast to static headspace, which looks only at the concentration of the volatiles in the headspace, the aim of dynamic headspace is to transfer as much as possible of the volatiles in the food to the trap. Some understanding of the transfer can obtained by considering model systems. As fruits, vegetables and plant materials have high concentrations (70-90%) of water, it is usefiil to consider model systems of solutions of volatile components in water. With such systems it is possible to calculate the total volume of sweep gas (Vg) needed to transfer a certain pCTcentage (P) of the dissolved volatile component to the trap (22,28). This can be done with the following relation ... 

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