Showing papers in "Cryogenics in 1981"

TL;DR: In this paper, the magnetic entropy of a typical 3-dimensional ferromagnetic substance near the Curie temperature as a function of temperature and magnetic field strength was calculated and compared with the experimental results.

TL;DR: In the past twenty years, a large variety of mechanically or electrically driven devices have been proposed and successfully operated and the basic principle of operation of each class of devices is shown and specific material problems and limitations are reported as mentioned in this paper.

TL;DR: In this paper, the effect of cryogenic temperatures on the mechanical, elastic, thermal and electrical properties of fiber-reinforced structural composites is reviewed and the status of fundamental research and test method development is reviewed.

TL;DR: In this paper, full and half wave superconducting transformer rectifiers are analyzed and modes of operation and loss mechanisms are detailed and a comparison between the behaviour of dynamos and rectifiers is presented.

TL;DR: In this article, fracture toughness, fatigue crack growth, and tensile properties data for five austenitic steels at 295, 76, and 4 K have been obtained, and two principal findings were the systematic variation of yield strength with nitrogen content and a systematic inverse correlation between fracture toughness and yield strength.

TL;DR: In this article, an asperity plowing model is proposed to account for the sliding behavior of unimpregnated superconducting magnet windings, and a simple epoxy coating technique was successful in eliminating initial rapid slip events, thereby completely stabilizing the sliding behaviour of a conductor/insulator combination.

TL;DR: A comprehensive survey of low-melting elements and compounds has been carried out, covering 190 substances from neon to carbon tetrachloride, which span T t values from 24.5 to 250.5 K.

TL;DR: In this paper, a correlation for the thermal conductivity of helium has been developed which covers the temperature range from temperatures just above the lambda line to 830 K, and densities up to about 160 kg m −3.

TL;DR: In this paper, an experimental magnetic refrigerator was designed to operate between 4.2 K and 1.8 K. The design performance was reached with 1/2 W capacity from two 18 cm3 magnetic parts.

TL;DR: The constants of the Bender equation of state were determined for both ethane and propane as mentioned in this paper, and for these two substances and for methane, ethylene and propylene pressure-enthalpy diagrams and tables of saturation properties were calculated.

TL;DR: The effect of the IVa element addition to the niobium core and that of gallium addition to matrix on the composition, growth rate and superconducting properties of the composite-processed Nb3Sn have been studied.

TL;DR: Measured dielectric constants and molar densities are reported for a number of liquefied petroleum gas (LPG) components and mixtures at cryogenic temperatures (220-250 K) and at standard temperature 15.6° C as discussed by the authors.

TL;DR: In this paper, a method for calculating the recovery heat flux in saturated He II heat transfer is presented, which combines the molecular kinetic equations for film boiling with the mutual friction description of heat flow in bulk He II.

TL;DR: In this article, a non mechanical gas sorption refrigeration system which could be powered by a low temperature heat source was designed and analyzed. The system involved no sealing, no mechanical moving parts and no active control.

TL;DR: In this paper, the void fraction in two-phase single component upward flow of both helium and nitrogen was carried out using the capacitance probe technique, and an electronic circuit was designed and constructed to accurately detect small changes in the dielectric constant resulting from changes in density in the two phase flow.

TL;DR: In this article, the authors investigated various heat flow regimes in a vertical slit opened at both ends of a helium II bath, as a means of simulating the properties of a typical heat transfer channel in a superconducting device.

TL;DR: In this paper, the workability of six heat transfer correlations for turbulent pipe flows of supercritical liquids when used for supercritical helium is tested by comparison with reference experimental data, and it is recommended to use for nonitteration heat transfer prediction in the cases of 1st kind (a given T w J and 2nd kind(a given q w ) boundary conditions, the correlations of ENIN and the correlation of Petukhov et al. respectively.

TL;DR: In this paper, a computer program for testing coil and protection design of a composed magnet system is presented, in which small high field magnets consisting of two uniaxial cylindrical coils of different superconducting materials are considered, each coil may be subdivided into several sections which are protected by parallel resistors.

TL;DR: In this article, a re-examination of the existing M S data shows that the elemental coefficients in linear equations are approximate and that a quadratic equation is more likely than a Eichelman and Hull equation.

TL;DR: In this article, the authors attempted to gather together much of the information required by the designer of dc superconducting magnets, including more information concerning performance of leads operating away from optimum conditions, comparisons of ideal cooling and a more realistic model for gas cooling.

TL;DR: In this paper, the thermal conductance of a screw-fastened joint between two blocks made of Al-alloys was measured at helium temperatures, using simple faced contact surfaces, electropolished and gold plated samples.

TL;DR: In this article, an experimental study of the thermal conductivity, electrical resistivity, critical temperature and upper critical field of solid solutions of NbTi with 22-80 at % Nb in cold-worked and recrystallized states is presented.

TL;DR: In this article, the effects of neutron irradiation on critical currents in NbTi of widely differing metallurgical starting conditions were studied, and the results showed a decreasing degradation of i c with increasing Ti-concentration indicating significantly different effects of neutromagnetic radiation on cell and precipitate pinning.

TL;DR: In this paper, the authors investigated the effect of the tilt angle of H o on the expulsion of magnetic flux from flat samples of Nb, NbTa, V and Pb in cooling, from Tc to 4.2 K, in static magnetic fields.

TL;DR: In this paper, the authors show that the stability of an intrinsically stable composite superconductor with respect to local heat pulses, depends on the Sc/Cu ratio and the filament distribution across the composite cross section.

TL;DR: In this paper, the shape, size and drag coefficient of the observed bubbles are reported for the bubble flow regime and a void fraction correlation for two-phase helium flow is proposed.

TL;DR: The specific heat of Abiezon N grease was measured between 0.1 K and 2.5 K where C = aT + bT 3 was found with a = 1.32 × 10 −6 J g −1 K −2 and b = 2.58 × 10−5 J g−1 K−4 as mentioned in this paper.