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New thermal transpiration data are given for He, Ar, N2, and CO in the temperature region between 77 and 300°K. These data are analyzed in terms of the “dusty-gas” flux equation and its differential approximation and in terms of a modified Weber–Schmidt equation. These models produce from the data values of the translational Eucken factor, which is related to the rotational relaxation number in a gas. The analysis indicates that a precise representation of the temperature dependence of the viscosity and independent information about the gas–tube surface interaction must be used to determine unambiguous values for the translational Eucken factor from these measurements.

2. J. F. Griffin, et al., Safety Analysis Report for Packaging (SARP): USA/5790/ BLF (ERDA-AL) and USA/5791/BLF (ERDA-AL), MLM-2242 (April 30, 1976), 89 pp. The containers were extensively tested and evaluated to show that they will function effectively with respect to all required standards and when subjected to normal transportation conditions and the sequence of four hypothetical accident conditions (free drop, puncture, ttiermal, and water immersion). In addition, a steady state temperature profile test was performed. A nuclear criticality safety 238 analysis was performed for PuO", a

Thermolecular pressure differences due to thermal transpiration were measured to find the corrections for low-temperature vapor-pressure thermometry using helium−3. The experimental apparatus consisted basically of several stainless-steel, pressure-sensing tubes, each connected to the same pressure container inside a cryostat. The upper, or warm, ends of the tubes were connected to differential pressure gauges outside the cryostat. The gauges measured the differences in warm end pressures between a 0.29-cm radius reference tube and tubes of 0.14-, 0.055-, and 0.0271-cm radii for a variety of cold end temperatures and pressures. The results for saturated and unsaturated helium−3 and unsaturated helium−4 are identical but greater at the maxima than the values computed from the semiempirical Weber—Schmidt equation, which was based on measurements with unsaturated helium−4. However, experimental data for saturated helium−4 in the low-pressure region were much higher than the Weber—Schmidt equation and the other data. This disagreement was attributed to superfluid film flow. An outline of the derivation of the differential equation describing thermal transpiration is given in this report. Theoretical predictions for the high-pressure region of saturated helium−4 are in agreement with the experimental data. It is concluded that a revision of the Weber—Schmidt equation is needed for precision thermometry.

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