Showing papers in "Cryogenics in 1999"

TL;DR: In this paper, the magnetocaloric effect was examined for ErCo 2, which shows a first-order magnetic transition from a ferrimagnetic to paramagnetic state at 32 K.

TL;DR: In this paper, a three-stage pulse tube refrigerator was constructed with a rotary valve to generate the pressure oscillations and achieved a minimum average temperature of 2.19 K. This is the lowest temperature achieved by mechanical refrigerators.

TL;DR: In this article, the specific heat capacity of Apiezon N high vacuum grease and of Duran borosilicate glass have been measured in the temperature range 16.2-319K and 1.75-323K, respectively.

TL;DR: In this paper, the thermal conductivity of Kapton tape at temperatures between 5 and 300 K was measured and the length of the tape was found to be 5.24×10 −3 T 1.02

TL;DR: In this article, the onset and damping behavior of the oscillation in a thermoacoustic prime mover with nitrogen as the working fluids is investigated. And the authors find that the damping point does not coincide with the onset temperature.

TL;DR: In this paper, the authors present a brief overview of the proposed Mars reference mission and the concomitant cryogenic fluid management technology, focusing on active cooling technology, and present a hybrid system optimized to minimize the launch mass while preserving the cryogenic propellants.

TL;DR: A fabrication technique of a Nb3Al strand using mass-production billets was developed for the framework of International Thermonuclear Experimental Reactor (ITER) Engineering Design Activity (EDA) as mentioned in this paper.

TL;DR: In this paper, the relationship between the effectiveness of a heat exchanger losing heat at the cold end and other resistances such as number of transfer units (NTU), longitudinal thermal resistance etc.

TL;DR: In this article, the authors describe a 4 He cryostat suitable for cooling a large multiband bolometric photometer for mm-waves, which has two large optical windows and a hold time longer than 2 weeks.

TL;DR: The CEA-SBT has acquired a considerable experience on both aspects and presented in this paper their past and current cryogenic sorption coolers activities as discussed by the authors, which can be used to design a compressor/pump which, by managing the gas pressure in a closed system, can condense liquid at some appropriate location and then perform an evaporative pumping on the liquid bath to reduce its temperature.

TL;DR: In this paper, a design concept for a loss-optimised superconducting 112.5 MW single-phase transmission cable is presented, where the interplay of cable geometry, operating conditions, transmitted power, and the resulting losses are considered.

TL;DR: In this article, the electrical insulation of the Large Hadron Collider (LHC) cables constitutes a thermal barrier between the conductor and the superfluid helium bath, which can prevent removal of the heat dissipated in the cable by the current rise in the dipoles or by the beam losses.

TL;DR: In this article, a low-loss Nb3Sn Rutherford cable with a thin core of AISI 316L stainless steel and uncored cables was measured at 4.2 K in sinusoidal magnetic fields of amplitudes 200 and 400 mT at frequencies of 5 to 90 mHz.

TL;DR: In this article, the authors measured the expansion coefficient of Torlon 4203 (polyamide-imide) as a function of temperature between 42 and 295 K and found that the thermal expansion is lower than that of most polymers.

TL;DR: In this article, the shape of the interface is calculated and it is found that for most anticipated applications, it is nearly cylindrical or spherical, and the depth of the liquid is variable.

TL;DR: In this article, the authors investigated the possibility of merging two of the next scientific missions of its HORIZON 2000 Programme, the fourth cornerstone mission, the Far InfraRed and Sub-millimetre Telescope (FIRST) and the third Medium-sized Mission M3, Planck (formerly Cobras/Sama).

TL;DR: In this article, a laboratory-scale superconducting energy storage (SMES) device based on a high-temperature super-conducting coil was developed, which operates between 64 and 77K, using liquid nitrogen (LN 2 ) for cooling.

TL;DR: In this paper, seven epoxy resins were chosen in order to evaluate thermo-mechanical properties, small-flaw strength, and creep deformation at low temperatures.

TL;DR: In this article, the effects of the contact pressure, the average interface temperature and the thickness of the interstitial layer on the thermal contact conductance of joints were evaluated at cryogenic temperatures.

TL;DR: In this article, the effect of longitudinal heat conduction through all the walls of heat exchangers is studied, and it is shown that the effect is not limited to the wall separating the fluid streams from the environment.

TL;DR: In this paper, a two-strand model cable was used to demonstrate the appearance of coupling currents much larger than the normal ac-coupling currents flowing around half twist pitch loops.

TL;DR: In this article, different types of pulse tube refrigerators are described by alternative phasor diagrams based on the volume flow rates applied at the ambient temperature inlets of the regenerator and of the pulse tube(s) This provides a simple means for finding the optimum phase shift between pressure and flow rate for PTRs operated with different kinds of phase shifters such as the orifice system, the inertance tube and the double inlet arrangement.

TL;DR: In this paper, an analysis of cryogenic liquefaction and storage methods for in-situ produced propellants (oxygen and methane) on Mars is presented, and a heat transfer analysis is included, resulting in predicted cryogenic tank surface temperatures and heat leak values for different conditions.

TL;DR: In this article, the effects of silver (Ag) additions on the mechanical properties and resistance to thermal shock of bulk YBa2Cu3O7-δ (YBCO) superconductors were evaluated.

TL;DR: In this article, the effect of hysteresis hardness on the relaxation of levitation forces in high T c superconducting (HTSC) magnetic bearings has been theoretically illustrated in a super-conducting half-space based on the Bean model and interpreted by the hysteretic behaviors of shielding current.

TL;DR: The space qualified pulse tube cooler is intended for greater than 10 year long-life space application and incorporates a non-wearing flexure bearing compressor vibrationally balanced by a motor-controlled balancer and a completely passive pulse tube cold head.

TL;DR: In this paper, a superconducting cable consisting of a several layers is described theoretically, and the current distribution in the cable as a function of cable current is described and solved for the case of an ideal Bean type II superconductor, taking into account layer current saturation at the critical current I c.

TL;DR: In this paper, the coupling time constant and a coupling loss formula were derived for High T c Super conductor (HTS) tapes, assuming their filamentary region to be an elliptical cylinder.

TL;DR: In this paper, the governing equations of practical micro miniature refrigerator heat exchanger are solved numerically to understand the complex convection-conduction interactions, and some guidelines are presented for the design of these heat exchangers.

TL;DR: The mK Cryocooler as mentioned in this paper is a liquid-He-free dilution refrigerator for neutron scattering research, which achieved the lowest sample temperature of 41 mK in the neutron beam experiment.