Design fundamentals of rapid cool-down Joule-Thomson (JT) cryostats and sensors

1994 ◽  
Author(s):  
Glenn E. Bonney ◽  
David M. Stubbs
Keyword(s):  
Rapid Cool

Microbiological Criteria for Raw Molluscan Shellfish

1992 ◽  
Vol 55 (6) ◽  
pp. 463-480 ◽  
Author(s):  
Keyword(s):  
Control Strategies ◽  
Product Distribution ◽  
Rapid Cool ◽  
Shared Responsibility ◽  
Control Measures ◽  
Plate Count ◽  
Wholesale Market ◽  
Water Classification ◽  
Microbiological Criteria ◽  
Shellfish Sanitation

The recommendations are designed to enhance the microbiological safety profile of raw molluscan shellfish which are likely to present inherent risks to consumers if adequate safeguards are not in place from harvest to consumption. Further, the document examines the “wholesale market standard” currently applied by the Interstate Shellfish Sanitation Conference (ISSC). Product testing alone is of limited value in assuring the safety of molluscan shellfish. For a market standard to be useful, it must be used as one of several control strategies. The recommendations are as follows:* Proper growing water classification and restriction of harvesting to those water areas are two of the most essential points in controlling both enteric pathogens of human origin and indigenous vibrios in molluscan shellfish. Without proper water classification and harvesting, any market standard applied would have a minimal effect on consumer protection.* Time/temperature control and monitoring during product distribution are essential to assure safety. Rapid cool down and continuous product chilling are also essential. When various combinations of warm harvest water and air temperatures exist, harvest requirements necessitating additional measures to assure rapid chilling should be implemented. In instances where this cannot be accomplished within a prescribed time, area closure may be necessary.* Minimize the introduction and multiplication of bacteria in molluscan shellfish during distribution through adequate sanitation and refrigeration requirements.* The Food and Drug Administration should develop a specific interpretation of the retail model code for HACCP-based control of raw molluscan shellfish to include purchase specification of properly tagged and refrigerated product.* The ISSC should incorporate the recommendations contained in this report into a revised National Shellfish Sanitation Program (NSSP) Manual of Operations and reissue the document as the Shellfish Sanitation Model Ordinance for adoption into state law. Further, the current “wholesale market standard” should be changed to include a modified aerobic plate count procedure which encourages the growth of Vibrio spp.* Fecal coliform/Escherichia coli should be retained as a guideline until state regulatory agencies are provided adequate assurance that all products have been harvested from properly classified growing waters. In the future, additional criteria may be appropriate if the National Indicator Study proposes changes in water classification standards.* The NSSP Manual should be expanded to include strict control measures from harvest through retail distribution.* Education programs can contribute to reducing risks associated with the consumption of raw molluscan shellfish. This is a shared responsibility of government and industry. These recommendations were adopted by the National Advisory Committee on Microbiological Criteria for Foods on July 18, 1991.

Effect of Injection Parameters on Warpage and Sink Index of High-Gloss Injection Parts

2014 ◽  
Vol 621 ◽  
pp. 88-93
Author(s):  
Yi Ning Song ◽  
Xi Ping Li ◽  
Ning Ning Gong
Keyword(s):  
Injection Molding ◽  
Mold Temperature ◽  
Rapid Cool ◽  
Orthogonal Experimental Design ◽  
Melt Temperature ◽  
Injection Process ◽  
Element Simulation ◽  
Injection Technology ◽  
Plastic Parts ◽  
Heat Injection

High-gloss injection molding technology is also called rapid cool and heat injection technology which can be used to eliminate weldmark on the surface of plastic parts, and improve the surface glossiness. However, the warpage, sink index and volume shrinkage of the parts are considered difficult to solve by using this technology. Reasons that cause the warpage and sink index of the parts were discussed in this paper firstly. Then, by using a LCD panel produced in practical injection process as an example, through orthogonal experimental design and finite element simulation, this paper discusses the effects of the injection molding parameters such as mold temperature, melt temperature etc. on warpage and sink index of the parts. The results are of great significance to help to set practical process parameters and assure the part quality in injection process.

Miniature Joule–Thomson (JT) Cryocoolers for Propellant Management

2004 ◽  
Author(s):  
W. Notardonato ◽  
G. Haddad ◽  
K. V. Krishna-Murty ◽  
J. Zhu ◽  
J. S. Kapat ◽  
...  
Keyword(s):  
Space Vehicle ◽  
Thermodynamic Cycle ◽  
Space Mission ◽  
Rapid Cool ◽  
304 Stainless Steel ◽  
Liquid Oxygen ◽  
External Temperature ◽  
Transfer Line ◽  
Heat Recuperator ◽  
Cryogenic Propellants

Boil-off of cryogenic propellants is an issue of concern in any space mission. There could be boil-off of liquid propellants in the cryogenic storage tank, transfer line or in the space vehicle external tank itself due to heat leak. The current insulation technology uses a multilayered thermal protective coating of 304 Stainless Steel and Welded Invar, which allows the propellant to withstand the extreme internal and external temperature variations generated during pre-launch, launch, and flight operations, which does not provide for zero boil-off (ZBO). Usage of a cryocooler to prevent propellant boil-off would potentially reduce the launch costs. Owing to its attractive features like simplicity, compactness and rapid cool-down characteristics, an innovative concept of using Joule-Thomson (JT) cryocoolers for prechilling, densification and ZBO applications of cryogenic propellants is focused upon. The liquid oxygen propellant transfer line at NASA Kennedy Space Center is considered for demonstration of the above concept. Various thermodynamic cycle parameters are optimized for the cryocooler to make the demonstration possible. Cycle optimization is done also taking into account the feasibility to develop some crucial components for the JT cryocooler like a micro channel heat recuperator and cold heads. Current state of developments in the heat exchanger is briefly described. Some advantages of using miniaturized cryocoolers in launch vehicle operations are also discussed.

RA 800H

Alloy Digest ◽  
1980 ◽  
Vol 29 (7) ◽  
Keyword(s):  
High Temperature ◽  
Heat Treating ◽  
Rapid Cool ◽  
High Temperature Strength ◽  
Good Resistance ◽  
Heat Resistant Alloy ◽  
Resistance To Oxidation ◽  
High Temperature Processing ◽  
Oxidation In Air ◽  
Rupture Properties

Abstract RA 800H is an austenitic iron-base, heat-resistant alloy with excellent high-temperature strength and good resistance to oxidation in air up to 2000 F (1090 C). High creep-rupture properties are obtained by a solution-anneal treatment followed by a rapid cool; grain size is controlled in the range 1 to 5 on the ASTM scale. RA 800H is free from embrittlement by sigma-phase formation. This alloy is well suited for high-temperature processing in refining or petrochemical service. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-373. Producer or source: Rolled Alloys Inc..

Simulations of the Pressurizer Safety Valve Stuck Open Accident for the Development of the Accident Sequences in the Low Power/Shutdown PSA

2004 ◽  
Author(s):  
Ho-Gon Lim ◽  
Jin-Hee Park ◽  
Seung-Chul Jang ◽  
Tae-Woon Kim
Keyword(s):  
Low Power ◽  
Nuclear Power ◽  
Safety Valve ◽  
Cooling System ◽  
Rapid Cool ◽  
Primary System ◽  
Core Damage ◽  
System Pressure ◽  
Operator Action ◽  
Accident Sequences

We have simulated the pressurizer safety valve (PSV) stuck open accident in a Korea Standard Nuclear power Plant (KSNP). The purpose of the simulation is 1) to investigate the mitigation function available for the important accident sequence having considerable core damage frequencies and 2) to support the determination of the accident sequences with relevant success criteria for the Low Power Shutdown (LP&S) Probabilistic Safety Assessment (PSA). The analysis showed that the PSV stuck open accident in a KSNP has both the characteristics of a small and medium LOCA in the sense that the primary system pressure decreases slowly but the break flow is sufficient enough to uncover the core in the early stages of the accident. we found that, in the accident sequence of a high pressure safety injection (HPSI) failure, core damage could occur earlier before reaching the actuation set-pressure of the safety injection tank (SIT) provided that no operator action is considered. We also performed the simulation of a rapid cool-down by a steam generator for this accident sequence to investigate the feasibility of the SIT injection before core damage occurs. From these simulations, if the operators start the rapid cool-down operation within 15 minutes, it was shown that SIT could be injected and core damage could be prevented if the subsequent Low Pressure Safety Injection (LPSI) and Shutdown Cooling System (SCS) is successfully operated.

Development and Testing of a Small-Scale Collins Type Cryocooler

2004 ◽  
Author(s):  
C. L. Hannon ◽  
B. J. Krass ◽  
J. Gerstmann ◽  
G. Chaudhry ◽  
J. G. Brisson ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Room Temperature ◽  
High Efficiency ◽  
Modular Design ◽  
Rapid Cool ◽  
Small Scale ◽  
Control Logic ◽  
Prototype Development ◽  
Multi Stage ◽  
Recuperative Heat Exchanger

Future spacecraft cooling and sensing systems will require advanced multi-stage cryocoolers capable of providing continuous cooling at multiple temperature levels ranging from 10K to 95K. A multi-stage 10K cryocooler is under development that applies modern microelectronic sophistication to achieve high efficiency in a reliable, compact design. The cryocooler is based upon a novel modification of the Collins cycle, a cycle commonly used in many high-efficiency terrestrial cryogenic machines. Innovations of the design include floating piston expanders and electromagnetic smart valves, which eliminate the need for mechanical linkages and thereby reduce the input power, size, and weight of the cryocooler in an affordable modular design. The floating piston expander and smart valves have been successfully developed in room temperature experiments using a series of proof-of-concept component prototypes. These experiments have resulted in a new warm-end configuration with improved expansion power dissipation and a new cryogenic valve design that reduces expander clearance volume and improves cold-end integration. A sophisticated LabView based control algorithm was developed over the course of the room temperature experiments that enables electronic control of the expansion cycle. Software based control will enable variable valve timing and adaptive control logic. This will result in a cryocooler with rapid cool-down and transient response capabilities as well as the ability to operate at high efficiency at arbitrary steady state load points. In parallel to this effort, a manufacturing method was developed to enable production of very long continuous lengths of small bore finned tubing. This tubing is used in the highly effective recuperative heat exchanger associated with each stage of the cryocooler. An engineering prototype has been designed that integrates the floating piston expander and recuperative heat exchanger as a functional cryocooler. The engineering prototype has been assembled and is currently undergoing development testing. This paper will present the results of the room temperature component development testing, the design of the engineering prototype, the results of initial engineering prototype development testing, and the direction of future development.

scholarly journals Enhanced Electrical Resistivity after Rapid Cool of the Specimen in Layered Oxide Li CoO2

2015 ◽  
Vol 75 ◽  
pp. 278-283 ◽  
Author(s):  
K. Miyoshi ◽  
K. Manami ◽  
J. Takeuchi ◽  
R. Sasai ◽  
S. Nishigori
Keyword(s):  
Electrical Resistivity ◽  
Rapid Cool ◽  
Layered Oxide

scholarly journals Rapid, cool sintering of wet processed yttria-stabilized zirconia ceramic electrolyte thin films

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Jun-Sik Park ◽  
Dug-Joong Kim ◽  
Wan-Ho Chung ◽  
Yonghyun Lim ◽  
Hak-Sung Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Rapid Cool ◽  
Yttria Stabilized Zirconia ◽  
Zirconia Ceramic ◽  
Stabilized Zirconia ◽  
Ceramic Electrolyte

CLEAN AND OXYGEN-COVERED Cu3Au(110): A SURFACE STRUCTURE INVESTIGATION WITH STM AND NICISS

1996 ◽  
Vol 03 (05n06) ◽  
pp. 1899-1908 ◽  
Author(s):  
HORST NIEHUS ◽  
THOMAS BAUMANN ◽  
MATTHIAS VOETZ ◽  
KARINA MORGENSTERN
Keyword(s):  
Surface Layer ◽  
Pure Copper ◽  
Copper Surface ◽  
Rapid Cool ◽  
Scanning Tunneling ◽  
Structure Model ◽  
Ion Scattering ◽  
Tunneling Microscopy ◽  
Careful Preparation ◽  
Low Energy Ion Scattering

Cu 3 Au (110) has been investigated by scanning tunneling microscopy (STM) and 180° low energy ion scattering and detection of neutrals (NICISS). Two different terminations would be possible on the basis of a bulk-truncated surface, a gold-rich or a pure copper surface layer. From the NICISS investigation the gold-rich termination has been found. Two surface modifications could be prepared. Rapid cool-down after annealing at 800 K results in a 2×1 LEED superstructure, but careful preparation and prolonged cooling below 600 K gives a LEED 4×1 superstructure. A new pairing row model has been proposed. Upon oxygen exposure at 330 K on the quenched 2×1 surface and subsequent annealing at 800 K, a 2×1 LEED superstructure presents itself with considerably sharper half order reflexes. NICISS data propose a segregation of Cu atoms to the surface layer forming -Cu-O- rows just above the Cu rows in the Au -rich layer. The 2×1 superstructure formed is in part similar to the well-known added row structure at Cu (110)-(2×1)-O. The structure model has been verified by direct imaging of the added rows with STM.

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