Knudsen effusion

The condition for Knudsen effusion that tire irreair free path of tire effusate should be less tlrair the diameter of the circular orifice, limits the usable vapour pressure of the material in the Knudsen cell to about 10 Pa, since the orifice diameter would have to be less than 1 mm at a higher pressure. 

Vapor pressures of phases in these systems were measured by the Knudsen effusion technique. Use of mass spectrometer-target collection apparatus to perform thermodynamic studies is discussed. The prominent sublimation reactions for these phases below 2000 K was shown to involve formation of elemental plutonium vapor. Thermodynamic properties determined in this study were correlated with corresponding values obtained from theoretical predictions and from previous measurements on analogous intermetallics. 

Vapor pressures were determined by using the Knudsen effusion technique. Effusion rates through and orifice contained in each sample cell were measured as a function of temperature by use of a mass spectrometer/target collection... 

Knudsen effusion technique and equation, vapor pressure determination. 100-101... 

Simpler methods of generation of intermediates in the gas phase are the thermal ones. The thermal reactions are carried out either in Knudsen effusion cells under equilibrium conditions or in flow reactors at very low pressure. Effusion cells are widely applied for the evaporation of monomeric... 

Figure 14 Free molecular flow through an orifice Knudsen effusion.

Knudsen effusion will be involved later as we discuss free molecular flow in channels and tubes. Knudsen effusion also finds application in the measurement of the vapor pressure of materials of low vapor pressure, typically in the... 

Samples were analyzed by gas chromatography (GC). Water solubility was determined by equilibration of analytical grade material with water at constant temperature. Equilibrium was approached from both under and super saturation conditions and samples were analyzed by GC. Vapor pressures were determined by the Knudsen effusion method. 

Twin Knudsen Effusion Apparatus for Small Samples of Radioactive... 

Knudsen effusion torsion-effusion torsion-effusion (continued) torsion-effusion (continued) ... 

Knudsen effusion, extrapolated-Antoine eq. from exptl data, Colomina et al. 1982)... 

Knudsen effusion pressure transducer gas saturation-GC in Boublik et al. 1984 ... 

Knudsen effusion/thermogravimetry technique, extrapolated Clausius-Clapeyron eq., Oja Suuberg 1998)... 

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