A bstract We make a first principle study of gravitational pressure in cosmic thermo- dynamics. The is directly derived from the unified law, fact Einstein field equation spherically symmetric spacetime. By using this pressure, we obtain thermodynamics for FRW universe, especially presenting state spacetime itself, i.e. P = ( R , T ) time. Furthermore, Joule-Thomson expansion as an application ...

Cryocooler performance and reliability are continually improving. Consequently, they are more and more frequently implemented by physicists in their laboratory experiments or for commercial and space applications. The five kinds of cryocoolers most commonly used to provide cryogenic temperatures for various applications are the Joule-Thomson, Brayton, Stirling, Gifford-McMahon, and pulse tube c...

Abstract The flow of a fluid through textiles has been studied for a number of years. Understanding the flow phenomena along with the corresponding environmental changes (pressure drop, concentration gradient, etc.) becomes important in many fields, such as liquid transport through geomembranes, effluent movement through filtration devices, and chemical movement through protective apparel. This...

The composition shifts of multicomponent mixtures used in low temperature Joule-Thomson refrigerators due to the different solubility in lubricant oils are studied in this paper. A compound of squalane with a high-boiling point temperature is treated as a kind of mineral oil. The Peng-Robinson (PR) equation of state (EOS) is selected to predict the solubilities, in which a group contribution mo...

The design, fabrication, testing and analysis of a microchannel heat exchanger, a key component for a microminiature Joule-Thomson Cryogenic Refrigerator is described. Results show that the heat exchanger can be fabricated efficiently and economically with the existing manufacturing technology. The heat exchanger was tested to be mechanically robust and durable under high pressure operating con...

Local ablation therapy is considered as a conventional treatment option for patients with early stage hepatocellular carcinoma (HCC). Although radiofrequency (RF) ablation is widely used for HCC, the use of cryoablation has been increasing as newer and safer cryoablation systems have developed. The thermodynamic mechanism of freezing and thawing used in cryoablation is the Joule-Thomson effect....

We analyze the high-temperature continuous-wave performance of 1.3m AlGaInAs/InP laser diodes grown by digital alloy molecular-beam epitaxy. Commercial laser software is utilized that self-consistently combines quantum-well bandstructure and gain calculations with two-dimensional simulations of carrier transport, wave guiding, and heat flow. Excellent agreement between simulation and measuremen...

This paper describes a lithography-based microfabrication process developed for a recuperative heat exchanger intended for use in a cryosurgical probe. The probe, which uses the Joule-Thomson (JT) cooling cycle, must achieve a temperature < -50°C, with a freeze rate of 25-50°C/min. The heat exchanger must maintain high stream-to-stream thermal conductance while restricting parasitic stream-wise...