Showing papers in "Cryogenics in 1979"

TL;DR: In this article, the functional dependence of time dependent heat transport in He II has been investigated and a well defined relationship between the time delay and the applied heat flux has been established.

TL;DR: The feasibility of a solid state type of refrigeration, which utilizes the electrocaloric effect in certain dielectric materials, has been investigated in this article, where the authors were limited to the temperature range where the refrigerator would absorb heat from a load at about 4 K and reject heat to a reservoir at about 15 K.

TL;DR: In this article, the influence of dc transport currents on alternating-field hysteresis loss was investigated for a single core superconducting wire, and the results were compared with calculations based on a slab model.

TL;DR: In this paper, a search procedure to determine the form of accurate vapour pressure equations has been extended to equations of state, using statistical tests to select terms to be included in an equation, whose form is not previously known, makes it possible to produce equations containing less terms than other proposed equations of comparable accuracy.

TL;DR: In this paper, the dielectric strength of very dense gases as well as of liquids is modeled by generalized similarity laws up to field levels of 107 V m−1, where boundary effects have a considerable influence.

TL;DR: In this paper, a collection of practical data on steady state heat transport in superfluid helium at atmospheric pressure is presented, given in the form of diagrams, which allow all the problems of linear steady-state heat transport with high atmospheric pressure to be solved directly.

TL;DR: In this paper, a computer-controlled system of four interlinked, cryogenic, fractional distillation columns capable of separating a feedstream of mixed isotopes (hydrogen, deuterium, and tritium) into four high-purity product streams needed in the development of a D-T fueling system for fusion power reactors was presented.

TL;DR: In this paper, the authors investigated transient pool boiling in liquid nitrogen for a process in which the boiling is initiated by a step-function application of power to a thin wire immersed in the liquid.

TL;DR: In this paper, a large superconducting dipole cooled by forced circulation of two-phase helium is described, and a short discussion of some cryogenic problems are presented together with the first results of the dipole's operation.

TL;DR: In this article, a theoretical model of heat-mass-transfer in perforated insulation, which takes into account the simultaneously and mutually acting mechanisms of heat transfer by a radiation, gas and spacer heat conduction, is proposed.

TL;DR: In this article, the authors investigated thermally driven acoustic oscillations using U-shaped tubes and showed that the stability limit of oscillation for helium gas predicted by theory agrees well with experimental results.

TL;DR: In this article, the Critical Current Margin (CCM) design criterion for superconducting magnet stability is presented, which is based on two magnet winding elements: heat transfer and composite conductor.

TL;DR: An NMR spectrometer where the transverse ac-component of magnetization is detected by a SQUID is described and its sensitivity is analyzed in this article, where the spectrometers were developed for studies of highly polarized metallic copper in low fields, for the main requirement was a constant gain over a wide frequency range.

TL;DR: In this article, new fluid phase transition phenomena involving He II were reported for isobaric, quasi-steady conditions during heat supply from solids at elevated pressures below the thermodynamic critical pressure.

TL;DR: In this article, the flow and pressure transients induced in stagnant supercritical helium in a pipe are calculated by energy transfers typical of those associated with the recovery of cable-in-conduit conductors (∼ 50−200 mJ cm−3 in 10−20 ms).

TL;DR: In this paper, the heat flux removed in the boundary transition from a vapour film to helium II was studied and it was found that the properties of heat flux can be essentially explained physically by non-equilibrium molecular-kinetic effects at the vaporization condensation interface.

TL;DR: In this article, the electrical resistance of simple screw-fastened joints between two bare copper blocks and blocks with various materials interposed was measured at 4.2 K. Based upon these measurements, ways to improve the low temperature thermal conductance of such joints are indicated.

TL;DR: In this article, the authors derived a numerical solution to these equations to determine the losses per field variation cycle, based on the concept of mean incremental permeability, which leads to some solutions in the closed form.

TL;DR: In this paper, a superconducting braid is wound into a coil to simulate the SC pulsed dipole magnet for a synchrotron from the viewpoint of cooling.

TL;DR: In this article, the authors studied the emission of acoustic waves in the frequency range 0.1 to 0.3 MHz in NbTi superconductors and found that the acoustic emission started at about 30% of the critical current and continued as the current decreased.

TL;DR: In this article, the specific heat coefficients of fifteen commercial and special grades of stainless steel, containing 12% to 25% Cr and 9% to 20% Ni, have been measured between 4 and 30 K.

TL;DR: In this paper, the superconducting state stability of commercial Nb-Ti superconductors under heat pulses, generated at different lengths of superconductor, was investigated and it was found that due to dissipation of heat along the supercondonductor, the energy of irreversible quench may exceed considerably the energy needed for its adiabatic heating to critical temperature Tc.

TL;DR: The vapour pressure of tetrafluoromethane has been measured at its triple point temperature (89.56 K) and at six higher temperatures up to 173 K as mentioned in this paper.

TL;DR: In this paper, a general method for optimizing ideal Claude cycles with multiple expansion engines is presented for two types of engine arrangements: in one case, the inlet temperature of one engine is equal to the outlet temperature of another engine.

TL;DR: The magnetic susceptibilities and magnetizations of seven austenitic stainless steel alloys, AISI 310S, 304L, 304N, 316 and 316L, and AWS 330 have been measured at temperatures down to 4.2 K as discussed by the authors.

TL;DR: In this paper, the authors present data on the total thermal contraction of Vespel SP-22 polymide resin and Stycast 1266 epoxy from room temperature to dry ice, liquid nitrogen, and liquid helium temperatures.

TL;DR: In this article, a comparison between the performance of dilution refrigerators operating with a single mixing chamber and with a double mixing chamber is made, and the important design features are given.

TL;DR: In this article, the minimum energy of thermal disturbances which barely leads a magnet to quench was found to depend largely on time duration and spatial length of the disturbances on the conductor.