Saturation, dynamic pressure obtained

A technique of making known vapor concentrations of reasonably volatile liquids in a diluent gas involves the use of the vapor pressure of the liquid (39). The diluent gas is passed through successive thermostatted bubblers to obtain a mixture determined by the saturation vapor pressure (SVP). Thus for ethanol, if the bubblers were maintained at 20°C (ethanol vapor pressure at 20°C is 43.9 Torr) (6 kPa) and the diluent gas flow were maintained low enough to ensure saturation, a dynamic standard would be generated with the following concentration ... 

Table III SO2 Vapor Pressure at 25 C Obtained by Dynamic Saturation or the S0 Electrode...

Molecular Simulations Molecular simulations are useful for predicting properties of bulk fluids and solids. Molecular dynamics (MD) simulations solve Newton s equations of motion for a small number (on the order of 10 ) of molecules to obtain the time evolution of the system. MD methods can be used for equilibrium and transport properties. Monte Carlo (MC) simulations use a model for the potential energy between molecules to simulate configurations of the molecules in proportion to their probability of occurrence. Statistical averages of MC configurations are useful for equilibrium properties, particularly for saturated densities, vapor pressures, etc. Property estimations using molecular simulation techniques are not illustrated in the remainder of this section as commercial software implementations are not generally available at this time. 

The eqtrilibrinm vapom presstrre over crystals of citric acid monohydrate (the decomposition pressirre of the hydrate) was determined by Marshall [7] nsing the dynamic air cmrent method [62, 63], His results are in a reasonable agreement with those of De Kmif et al. [8]. They used the static method by employing a diaphragm manometer. Oechler [9] applying a direct manometric technique measured vapour pressure of water over solutions saturated with both, the monohydrate and anhydrous citric acid, and obtained practically the same results. These three sets... 

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