Showing papers in "Cryogenics in 1980"

TL;DR: In this article, the authors present the basic uniaxial-strain scaling relationship and focus on its application to Nb3Sn conductors, and propose a general scaling relation which unifies the usual temperature scaling relation with this strain-scaling relation.

TL;DR: In this article, the construction and performance of a double-stage nuclear demagnetization refrigerator are reported. The two nuclear stages are thermally connected to each other and to the dilution refrigerator by superconducting aluminium heat switches.

TL;DR: In this paper, the shape of the voltage-current characteristics of multifilament wires, and the parameter's dependence on temperature and magnetic field were investigated in different ranges of magnetic field, temperature and current.

TL;DR: In this article, the sliding behavior of various metal-insulator pairs has been carried out to discover which combinations will reduce or eliminate rapid slip events which lead to high local heating, and the results indicate that desirable sliding behaviour can be achieved, at 4.2 K, when the hardness of the metal and insulator are well matched.

TL;DR: In this paper, a number of unexpected phenomena of the mechanical behavior of metals, due to the specific character of dislocation motion and interaction are analysed using the strength and plasticity characteristics of titanium of different grades of purity and its binary alloys with aluminium, vanadium, niobium and oxygen at 4.2-300 K.

TL;DR: Theoretical studies for transient field losses in multifilamentary composite conductors carrying a dc transport current are presented in this article, where the analysis of the total loss is split into separate calculations of the magnetization loss and the loss due to the dynamic resistance.

TL;DR: In this paper, a new expression for the full recovery and cold end recovery currents was proposed, together with an exact and finite propagation velocity when the transport current tends towards the critical current.

TL;DR: A two-part State of the art review and survey of work performed at the Massachusetts Institute of Technology since 1974 is presented in this paper, which covers initial concepts as well as the development and testing of Niobium Titanium conductors.

TL;DR: In this article, the reaction of a superconducting cable formed by a number of strands is investigated assuming that only one strand became normal due to some disturbance, and the electrodynamics of current redistribution to the intact strands, the associated dissipation and the occuring temperature rise are calculated for soldered and indulated strands.

TL;DR: In this article, a review acquaints the reader with the novel ideas that have evolved during the last five years regarding the stability of internally cooled superconductors, including zero-flow recovery, heating-induced flow, multivalued stability, and the maximum cooling capacity of confined supercritical helium.

TL;DR: In this article, the authors derived differential equations to calculate the time dependence of the magnetic moment of screening currents in a round composite conductor under relatively high amplitudes and variation rates of a transverse external field.

TL;DR: In this paper, the maximum level of quench voltage that can be left undetected was derived for stable superconducting magnets wound with copper substrate composite conductor, which is tens of millivolts, independent of current density.

TL;DR: In this article, the authors compare the Josephson junction noise thermometer and 60 Co γ-ray anisotropy thermometer from 0.01 K to 0.05 K.

TL;DR: In this article, the mechanical properties of organic insulators, such as polyimide, epoxy resins and fiber reinforced epoxies, are measured in liquid helium and in liquid nitrogen without warm up.

TL;DR: In this paper, acoustic emission generated in a composite copper multifilamentary NbTi conductor has been measured Its source appears to be dissipation associated with the Lorentz force induced flux motions.

TL;DR: The potential applications of superconductivity in space are examined in this paper, where it is shown that superconducting oscillators have achieved better frequency stability that any other device for averaging times of 10 s to 1000 s. Such a high stability results from the use of solid niobium resonators having Q factors greater that 10 to the 10th.

TL;DR: Growth of Nb 3 Sn layer formed in a multifilamentary composite of bronze matrix by solid state diffusion has been investigated and its T c values are measured after different time periods of diffusion anneal as mentioned in this paper.

TL;DR: In this paper, the authors investigated the consequences of a space and time dependent energy input into the cooling system of a forced flow cooled superconducting magnet, based on a proved computer code for calculation of instationary fluid flows, a new program was developed which is able quantitatively to calculate pressure and temperature transients caused by heat pulses.

TL;DR: In this article, the losses due to coupling currents are calculated for a superconducting cable and it is shown that if the wire twist pitch is different from the cable twist pitch, the losses diverge as 1/(1-f), where f is the volume fraction of wire in the cable.

TL;DR: In this paper, a new magnetic refrigerator design based on the anisotropic nature of paramagnetic materials is presented, and the key advantages of the rotational cooling concept are (1) a single, rotary motion is required, (2) magnetic field shaping is not a problem, and (3) the refrigerator can be smaller than comparable magnetic refrigerators because the working material is entirely inside the magnet at all times.

TL;DR: A survey of commercially available strain gauges potentially suitable for testing of superconducting magnets is presented in this article, along with the results of a test for the temperature dependence of the magnetorestistance of modified Karma alloy foil gauges in the liquid helium temperature range.

TL;DR: Young's moduli were determined dynamically for two fibreglass-cloth-epoxy composites in the warp, fill, and normal directions between room temperature and liquid nitrogen temperature.

TL;DR: In this article, the authors describe the cryostat system which enables superfluid helium at 1.8 K and atmospheric pressure to be used in superconducting magnets for fusion and high field research.

TL;DR: In this article, the characteristics of a superfluid plug as a nonmechanical control device for supplying cold helium vapor on demand from a liquid superfluid-helium container were investigated.

TL;DR: In this paper, a filament wound vessel was filled with liquid nitrogen and subjected to 2000 pressure cycles to 2068 N cm −2 (3000 psi) without degradation of the structural capability of the vessel.

TL;DR: In this article, the voltage-temperature characteristics of p-n junction diodes and point contact Diodes down to liquid helium temperatures have been investigated, and it has been shown that the current through these DAs plays a significant role in deciding the sensitivity as well as in limiting the temperature range of relatively linear response of the DAs when used as cryogenic temperature sensors.

TL;DR: In this article, a graphical method for determining temperature below 10 K using properties of superconductors is reported, where a small superconducting wire which has known current/voltage characteristics can be used as a temperature sensor.

TL;DR: Using a diamond anvil high pressure cell, the superconducting transition temperature has been determined by a new technique based on an ac bridge method, and the sensitivity is improved by the shield plates of a high-Tc superconductor, by which the magnetic flux is concentrated on the sample as mentioned in this paper.

TL;DR: The work-hardening modulus varied correspondingly from 1.9 GPa to 9.6 GPa as a function of tin content as discussed by the authors, and the 0.02% offset yield strength varied from 76 MPa for pure copper to 241 MPA for an 8.2 w/o Sn bronze.

TL;DR: A new high field test facility has been constructed for overall property measurements of the conductors developed for the superconducting coils of the TORUS II Tokamak project proposed by the EURATOM-CEA Association as mentioned in this paper.