Showing papers in "Cryogenics in 2002"

TL;DR: The design strategy described in this paper is a guide for the design and development of thermoacoustic coolers and the optimization of the different parts of the refrigerator will be discussed.

TL;DR: In this article, the authors present a survey of the state-of-the-art of Stirling-type cryocoolers, with a focus on cooling performance, mass and size, cost, lifetime and reliability.

TL;DR: In this paper, the maximum temperature differences of three types of two-stage thermoelectric (TE) coolers are analyzed, which are the ones with thermocouples at two stages electrically connected in series and parallel and electrically separated, respectively.

TL;DR: In this paper, the authors describe the construction and performance of a thermoacoustic refrigerator, which consists of three major parts: the refrigerator, the electronic apparatus necessary for the measurements and acquisition of the experimental data, and the gas-control panel which is used to fill and purge the system and to prepare gas mixtures.

TL;DR: In this article, a dilution refrigerator is described which is precooled by a two-stage pulse-tube refrigerator and thus no cryoliquids are needed to operate this millikelvin cooler.

TL;DR: In this article, a current diffusion model is applied to simulated current transfer between filaments inside a Nb 3 Sn strand in a cable during a T cs (ramped temperature at constant current) measurement.

TL;DR: In this article, the authors analyzed the characteristics of the linear compressor for Stirling cryocooler and found that the operating frequency has a significant effect on the input power characteristics, and the compressor with higher charging pressure has high pressure ratio.

TL;DR: In this article, a portable "permanent" superconducting magnet system is explored, which involves a persistent-mode high-temperature super-conducting (HTS) magnet that is cooled by a solid heat capacitor.

TL;DR: In this paper, the critical current density (Jc) of a bronze-route niobium-tin wire was measured for magnetic fields (B) up to 15 T as a function of temperature (T) from 6 K up to 16 K in the strain (e) range between −0.7% and + 0.7%.

TL;DR: In this article, an efficient two-stage helium/hydrogen sorption cooler is proposed with a cooling power of 10 mW at 5 K, which needs only 3 W of input power and applies two passive radiators at 50 and 70 K.

TL;DR: In this paper, the potential performance advantages of a solid nitrogen cooled "permanent" high-temperature superconducting (SN2/HTS) magnet system over a liquid helium cooled LHe/LTS system are explored.

TL;DR: In this paper, a boron-free R-glass fiber reinforced tape, vacuum-pressure impregnated in a DGEBA epoxy system and partly interleaved with polyimide-foils (e.g. Kapton-H-folds), was used for the ITER toroidal field (TF) model coil.

TL;DR: In this paper, the authors focused on the transient regime in an annular thermo-acoustic prime-mover and showed that several nonlinear phenomena can play a role in the amplification and saturation regimes, including acoustically induced conductivity, forced convection due to acoustic streaming, minor loss phenomenon and saturation due to harmonic generation.

TL;DR: In this paper, a numerical six-element network model is developed to simulate the conditions and behaviour of the last stage cable elements of a full-size ITER conductor, and the experimental data, mainly in terms of voltage-current (VI) or -temperature (VT) characteristics, are obtained on the central solenoid insert coil (CSIC) experiment performed in Naka (Japan) in the framework of the research for ITER.

TL;DR: In this paper, a 13 T-46 kA Nb3Al conductor with stainless steel jacket has been developed in order to demonstrate applicability of an nb3al conductor with react-and-wind technique to ITER-TF coils.

TL;DR: In this article, a mathematical model of a one-stage Oxford split-Stirling cryocooler has been made to simulate its dynamic performance and a set of governing equations has been solved by a numerical method.

TL;DR: In this paper, the influence of mixture composition on the temperature distribution in the counter flow heat exchanger used in mixture Joule-Thomson refrigerators is investigated, and the results show that the temperature profile as well as the locations of the pinch points are determined by the mixture compositions.

TL;DR: In this article, the authors present experimental and theoretical studies of magnetic levitation of hydrogen gas bubble surrounded by liquid hydrogen confined in a semi-transparent spherical shell of 3 mm internal diameter.

TL;DR: In this article, the authors present the design, manufacturing process and test results in the optimum operating condition for the free piston free displacer (FPFD) type Stirling cryocooler designed and manufactured by Korea Institute of Machinery and Materials.

TL;DR: In this article, the design and the optimization of a miniature double inlet pulse tube refrigerator (DIPTR) dedicated to infrared sensor applications are presented, and the hydrodynamic and thermal behaviors of the cooler are predicted by means of two different approaches: a classical thermodynamic model and a model based on an electrical analogy.

TL;DR: In this paper, the authors analyzed the performance of the inertance pulse tube (IPTR) over a limited range of frequencies and found that the IPTR is superior to that of the orifice pulse tube refrigerator (OPTR).

TL;DR: In this paper, the effect of magnetic flux creep on the levitation stability of high-temperature superconductors was studied and the theory of relaxation of magnetization and force for a partial and full penetration of the critical state was considered.

TL;DR: In this paper, the windings of the superconducting magnet coils for the ITER-FEAT fusion device are affected by high mechanical stresses at cryogenic temperatures and by a radiation environment, which impose certain constraints especially on the insulating materials.

TL;DR: In this article, the low temperature thermal properties of polypropylene copolymer (PP) were studied using the tunnelling model for phonon scattering, and the measured thermal properties show that PP is suitable for use as thermal insulating support material in cryogenic devices.

TL;DR: In this paper, a new concept of thermal design to optimize the operating temperature of high temperature superconductor (HTS) magnets is presented, aiming simultaneously at small size and low energy consumption.

TL;DR: In this paper, a rigorous thermodynamic temperature-entropy (T-s) diagram is constructed to identify the heat leak as well as the total input power of both Peltier current leads and converntional all-copper leads.

TL;DR: In this paper, a horizontal axle-type flywheel energy storage system was manufactured using high-T c superconductor bearings, which was designed to have an energy storage capacity of 440 Wh at its operating speed of 40,000 rpm, which is way above two rigid body mode critical speeds.

TL;DR: In this article, thin film resistors were designed and fabricated using a CrSi/TiW/Al metal system on optical quality quartz substrates and the resistor values range from 100 mega-ohms to over 650 megaohms and are Johnson noise limited at LHe temperatures.

TL;DR: In this article, the design of a double inlet pulse tube refrigerator is investigated by means of an analogy with an electric circuit and the results obtained are compared with both those of the thermodynamic model (Part A) and experiments.

TL;DR: In this paper, a new type of pulse tube refrigerator named as V-M type pulse tube fridge is introduced, where thermal compressor similar to that of a V-m cryocooler is used instead of mechanical compressor.