The Hampson—Linde cycle is a process for the liquefaction of gases , especially for air separation. William Hampson and Carl von Linde independently filed for patents of the cycle in Hampson on 23 May and Linde on 5 June The Hampson—Linde cycle introduced regenerative cooling , a positive-feedback cooling system. The Hampson—Linde cycle differs from the Siemens cycle only in the expansion step.
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Low capacity Linde-Hampson nitrogen liquefier. A closed-cycle Linde-Hampson nitrogen liquefier was developed incorporating a new, non-clogging, demand flow Joule-Thomson nozzle. The flow area of the nozzle, a tapered annular orifice, is regulated by a very rugged load-sensitive differential thermal expansion scheme and by a manually adjustable micrometer mechanism.
Labyrinth flow spoilers within the orifice provide turbulent voids which break up and clear contaminants from the flow. The system's four-stage compressor features sealed, oil-free compression spaces and a very compact nested piston configuration with a minimum of moving parts and drive complexity.
The drive mechanism is a rolling Scotch yoke which minimizes piston side forces and seal wear for prolonged operating life. The closed-cycled system is controlled by an innovative load-responsive electronic feedback circuit which further reduces wear and input power.
Thermodynamic analysis of single-stage and multi-stage adsorption refrigeration cycles with activated carbon—ammonia working pair. Cycle mathematical models for single, two and three-stage cycles were established on the basis of thorough thermodynamic analysis. According to simulation results of thermodynamic evaluation indicators such as COP coefficient of performance , exergetic efficiency and cycle entropy production, multi-stage cycle adapts to high condensing temperature, low evaporating temperature and low heating source temperature well.
It was found that both COP and exergetic efficiency are of great reference value in the choice of cycle, whereas entropy production is not so useful for cycle stage selection. Finally, the application boundary conditions of single-stage , two-stage, and three-stage cycles were summarized as tables according to the simulation results, which provides reference for choosing optimal cycle under different conditions.
Thermodynamic design of hydrogen liquefaction systems with helium or neon Brayton refrigerator. A thermodynamic study is carried out for the design of hydrogen liquefaction systems with helium He or neon Ne Brayton refrigerator. Eight different cycles are proposed and their thermodynamic performance is investigated in comparison with the existing liquefaction systems.
The proposed cycles include the standard and modified versions of He Brayton refrigerators whose lowest temperature is below 20 K. The Brayton refrigerator is in direct thermal contact with the hydrogen flow at atmospheric pressure from ambient-temperature gas to cryogenic liquid.
The Linde-Hampson system pre-cooled by a Ne Brayton refrigerator is also considered. Full cycle analysis is performed with the real properties of fluids to estimate the figure of merit FOM under an optimized operation condition. It is concluded that He Brayton refrigerators are feasible for this small-scale liquefaction, because a reasonably high efficiency can be achieved with simple and safe low-pressure operation. The complete cycles with He Brayton refrigerator are presented for the development of a prototype, including the ortho-to-para conversion.
Study Design: Descriptive case series. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Results: Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patients age was On follow-up, 7 patients Five Two patients 6. Re-do perineal urethroplasty was eventually performed. The overall success rate was Conclusion: Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures.
Descriptive case series. Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively.
Mean patient's age was Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures.
Optimum operating regimes of common paramagnetic refrigerants. Adiabatic Demagnetization Refrigerators ADRs are commonly used in cryogenic laboratories to achieve subkelvin temperatures. For these applications, refrigerants with high ratios of cooling capacity to volume, or cooling capacity to mass are usually required. These graphs are valid for single stage cycles. The selection of the refrigerants is uniquely dependent on the starting conditions of the refrigeration cycle temperature and magnetic field density and the desired final temperature.
Only thermodynamic properties of the refrigerants have been taken into account, and other important factors such as availability and manufacturability have not been considered. C Elsevier Ltd. All rights reserve Nov 3, The design philosophy, construction and measured performances of a single stage , single entry centrifugal pump The constructed centrifugal Thermoacoustic refrigeration. A new refrigerator which uses resonant high amplitude sound in inert gases to pump heat is described and demonstrated.
The phasing of the thermoacoustic cycle is provided by thermal conduction. This 'natural' phasing allows the entire refrigerator to operate with only one moving part the loudspeaker diaphragm. The thermoacoustic refrigerator has no sliding seals, requires no lubrication, uses only low-tolerance machine parts, and contains no expensive components.
Because the compressor moving mass is typically small and the oscillation frequency is high, the small amount of vibration is very easily isolated. The design, fabrication, and performance of the first practical, autonomous thermoacoustic refrigerator , which will be flown on the Space Shuttle STS , are described, and designs for terrestrial applications are presented. Flammable refrigerants.
Due to their flammable nature, safety aspects have to be considered carefully. The world-wide situation concerning acceptability and practical application of flammable refrigerants is becoming more and more complex and. Single stage reconstruction of complex anterior urethral strictures. Directory of Open Access Journals Sweden.
Full Text Available Purpose: Single stage reconstruction of long, com-plex urethral strictures is technically demanding and may require the use of more than one tissue transfer technique. We describe our experience in the manage-ment of such strictures with a variety of urethroplasty techniques.
Materials and Methods: Between and , 25 men mean age In 10 patients a single tissue transfer technique was used.
Results: The median ,follow-up was The mean postoperative flow rate improved to Recurrent stricture developed in 5 Conclusions: Successful outcome of single stage re-construction of long complex strictures can be achieved with a combination of various tissue transfer methods. The urologist who has a thorough knowledge of penile skin and urethral vascular anatomy and a wide array of substitution techniques in his armamentarium can un-dertake approach to such strictures.
A supply system's fill rate is the fraction of demand that is met from on-hand inventory. This paper presents formulas for the fill rate of periodic review supply systems that use base-stock-level policies. The first part of the paper contains fill-rate formulas for a single-stage system and general distributions of demand.
When demand is normally distributed, an exact expression uses only the standard normal distribution and density functions, and a good approximation uses only the standard In this paper the issue of control strategies for single-stage photovoltaic PV inverter is addressed.
Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented The control strategy was tested experimentally on 1. One-dimensional numerical simulation of the Stirling-type pulse-tube refrigerator. Change of title: One-dimensional numerical simulation of the Stirling-type pulse-tube cooler.
Pulse-tube refrigeration PTR is a new technology for cooling down to extremely low temperatures. In this paper a particular type, the so-called Stirling single-stage refrigerator , is considered.
Thermodynamic simulation of condensation heat recovery characteristics of a single stage centrifugal chiller in a hotel. The cooling capacity of the chiller unit is about kW. The chiller unit has been set and tested, and the work refrigerant is R A heat exchanger has been set between outlet of the compressor and the condenser for sanitary hot water supplying.
Then the chiller unit is a kind of combined system that can provide sanitary hot water supplying and air conditioning simultaneously. A thermodynamic simulation model of the combined system has been established with the system simulation toolbox Simulink. Performance of the components and the combined system of the chiller unit has been studied over a wide range of operating conditions. The potential energy and fuel cost saving associated with the use of the proposed combined system for a typical hotel in south China has been estimated.
It is showed that the combined system of the chiller unit is very useful in hotel buildings. And the thermodynamic simulation model of the combined system is significance for the optimization of parameters of the chiller unit such as condensation and evaporation temperature, mass flow of the sanitary hot water and size of hot water storage tank. Recent investigations on refrigerants for magnetic refrigerators.
In development of the magnetic refrigerator , an important problem is selection of magnetic materials as refrigerants. The main purpose of the present paper is to discuss the magnetic and thermal properties necessary for these refrigerants and to report recent investigations.
Magnetic refrigerants can be expediently divided into two groups, one for the Carnottype magnetic refrigerator below 20 K and the other for the Ericsson-type refrigerator. The required physical properties of refrigerants in each type of the magnetic refrigerator are first discussed.
And then, the results of recent investigations on the magnetic, thermal and magnetocaloric characters of several promising magnetic refrigerants are shown. Finally, a brief prospect of the magnetic refrigerants and refrigerators is given.
New results for single stage low energy carbon AMS. Patent 6,, B2 has been built and tested. The injector includes two sample ion sources, electrostatic and magnetic analysis, and fast sequential injection.