This study investigated the effects of cryogenic treatment and tempering temperature applied after on mechanical microstructural properties AISI 431 martensitic stainless steel. After conventional heat (CHT), steel samples were cryogenically treated at -180 °C for 6 hours then tempered 200 (CT200) 300 (CT300) 2 hours. these processes, hardness measurement, tensile test, abrasion test carried ou...

GaAs junction field-effect transistors (JFETs) are promising for deep cryogenic (<10K) readout electronics applications. This paper presents the structure and fabrication of GaAs JFETs and their performance at 4 K. It is shown that these JFETs operate normally at 4 K, with no anomalous behavior such as kinks or hysteresis. The noise voltage follows a 1 / f i dependence and is approximately 1 ~ ...

The Cryogenic Dark Matter Search experiment uses germanium and silicon detectors cooled to cryogenic temperatures in a direct search for weakly-interacting massive particles in our Galaxy. The novel detectors allow a high degree of background rejection by discriminating between electron and nuclear recoils through the simultaneous measurement of the energy deposited in phonons (heat) and ioniza...

A large heat load caused by thermal radiation through a metal shield pipe was observed in a cooling test of a cryostat for a prototype of a cryogenic interferometric gravitational wave detector. The heat load was approximately 1000 times larger than the value calculated by the Stefan-Boltzmann law. We studied this phenomenon by simulation and experiment and found that it was caused by the condu...

There are a number of systems in which supercritical cryogenic fluids are used as coolants or propellant fluids. In some modern military aircraft, the fuel is pressurized above its critical point and used as a coolant to remove heat from the aircraft engine. Accurate prediction of heat transfer coefficients to turbulent flows of supercritical fluids is essential in design of such systems. One o...

In this study, beryllium-copper alloy was subjected to around -150° F for cold treatment and to around -300° F for cryogenic treatment and the effects of these cold and cryogenic treatments on the machinability of beryllium-copper workpieces in electro discharge machining have been investigated. Experimental results showed about 20-30 % increase in material removal rate of cold and cryogenic tr...

-Electrical discharge machining (EDM) process, at present is still an experience process, wherein selected parameters are often far from the optimum, and at the same time selecting optimization parameters is costly and time consuming. In this paper cryogenic treatment is used for increasing the material removal rate and lowering the tool wear rate. cryogenic treatment is a process of keeping th...