New vapour pressure measurements for argon and nitrogen and a new method for establishing rational vapour pressure equations

Recommended values of temperature on the International Temperature Scale of 1990 are given for a large number of secondary reference points, together with assessments of the uncertainties of these values.

https://iopscience.iop.org/article/10.1088/0026-1394/33/2/3/pdf

Recommended values of temperature on the International Temperature Scale of 1990 for a selected set of secondary reference points

A series of research reports were prepared several years ago for the National Bureau of Standards in which the vapor pressure and heats of vaporization and sublimation of liquids and solids of cryogenic interest below 1-atm pressure were computed as functions of the thermodynamic temperature from appropriate thermodynamic relations using what was then considered to be the best available physical property data. The results of these calculations were presented in tabular form as a function of absolute temperature from approximately the normal boiling point of the condensed gas to approximately the temperature at which the vapor pressure of the solid is about 10−15 torr. The original reports referred to in the references for this paper should be consulted for details.

Vapor Pressure and Heats of Vaporization and Sublimation of Liquids and Solids of Interest in Cryogenics below 1-atm Pressure

Chemical and physical processes, such as heterogeneous chemical reactions, light scattering, and metamorphism occur in the natural snowpack To model these processes in the snowpack, the specific surface area (SSA) is a key parameter In this study, two methods, computed tomography and methane adsorption, which have intrinsically different effective resolutions – molecular and 30 μm, respectively – were used to determine the SSA of similar natural snow samples Except for very fresh snow, the two methods give identical results, with an uncertainty of 3% This implies that the surface of aged natural snow is smooth up to a scale of about 30 μm and that if smaller structures are present they do not contribute significantly to the overall SSA It furthermore implies that for optical methods a voxel size of 10 μm is sufficient to capture all structural features of this type of snow; however, fresh precipitation appears to contain small features that cause an under-estimation of SSA with tomography at this resolution The methane adsorption method is therefore superior to computed tomography for very fresh snow having high SSA Nonetheless, in addition to SSA determination, tomography provides full geometric information about the ice matrix It can also be advantageously used to investigate layered snow packs, as it allows measuring SSA in layers of less than 1 mm

/pdf/measuring-the-specific-surface-area-of-snow-with-x-ray-5y6p1hil1j.pdf

Measuring the specific surface area of snow with X-ray tomography and gas adsorption: comparison and implications for surface smoothness

We construct anH-function suitable for a system of dense hard spheres satisfying the (modified) nonlinear Enskog equation and we show that∂tH ⩽ 0. The equality sign holds only when the system has reached absolute equilibrium, in which caseS=− kBH becomes the exact equilibrium entropy of the hard-sphere fluid.

H-theorem for the (modified) nonlinear Enskog equation

The vapour pressure of liquid nitrogen

The vapour pressure of liquid oxygen

The temperatures at the transition points in solid oxygen

On the definition of an international practical temperature scale. The interpolation of differences in the resistance ratios of platinum thermometers between 91 K and 14 K

R. Muijlwijk

Papers

The vapour pressure of liquid nitrogen

The vapour pressure of liquid oxygen

The temperatures at the transition points in solid oxygen

On the definition of an international practical temperature scale. The interpolation of differences in the resistance ratios of platinum thermometers between 91 K and 14 K

Comparisons of platinum resistance thermometers with the hydrogen vapour-pressure thermometer