LDR cryogenics

A brief summary from the 1985 Large Deployable Reflector (LDR) Asilomar 2 workshop of the requirements for LDR cryogenic cooling is presented. The heat rates are simply the sum of the individual heat rates from the instruments. Consideration of duty cycle will have a dramatic effect on cooling requirements. There are many possible combinations of cooling techniques for each of the three temperatures zones. It is clear that much further system study is needed to determine what type of cooling system is required (He-2, hybrid or mechanical) and what size and power is required. As the instruments, along with their duty cycles and heat rates, become better defined it will be possible to better determine the optimum cooling systems

Membranoproliferative glomerulonephritis in patients with chronic venous catheters: a case report and literature review.

Chronic indwelling catheters have been reported to be associated with membranoproliferative glomerulonephritis (MPGN) via the activation of the classical complement pathway in association with bacterial infections such as coagulase negative staphylococcus. We herein provide supporting evidence for the direct causal relationship between chronic catheter infections and MPGN via a case of recurrent MPGN associated with recurrent catheter infections used for total parenteral nutrition (TPN) in a man with short gut syndrome. We also present a literature review of similar cases and identify common clinical manifestations that may serve to aid clinicians in the early identification of MPGN associated with infected central venous catheterization or vice versa. The importance of routine monitoring of kidney function and urinalysis among patients with chronic central venous catheterization is highlighted as kidney injury may herald or coincide with overtly infected chronic indwelling central venous catheters

Investigation of a para-ortho hydrogen reactor for application to spacecraft sensor cooling

The utilization of solid hydrogen in space for sensor and instrument cooling is a very efficient technique for long term cooling or for cooling at high heat rates. The solid hydrogen can provide temperatures as low as 7 to 8 K to instruments. Vapor cooling is utilized to reduce parasitic heat inputs to the 7 to 8 K stage and is effective in providing intermediate cooling for instrument components operating at higher temperatures. The use of solid hydrogen in place of helium may lead to weight reductions as large as a factor of ten and an attendent reduction in system volume. The results of an investigation of a catalytic reactor for use with a solid hydrogen cooling system is presented. Trade studies were performed on several configurations of reactor to meet the requirements of high reactor efficiency with low pressure drop. Results for the selected reactor design are presented for both liquid hydrogen systems operating at near atmospheric pressure and the solid hydrogen cooler operating as low as 1 torr

Investigation of external refrigeration systems for long term cryogenic storage

Selection and optimization of space cryogenic storage tank

Comparison of guidelines for the management of patients with high‐risk and advanced cutaneous squamous cell carcinoma – a systematic review

The management of high‐risk cutaneous squamous cell carcinoma (cSCC) can be a challenge as evidence from high quality clinical trials is rare. Guideline developers are challenged to provide practical and useful guidance for clinicians even in the absence of good evidence. In order to compare treatment recommendations for high‐risk and advanced cSCC among national and international guidelines and to extract the most precise guidance provided, a systematic search was carried out in guideline databases Medline and Embase with a cutoff of 4 March 2019. Treatment recommendations for predefined clinical scenarios were extracted from selected guidelines and compared qualitatively. Five guidelines published from 2015 to 2018 were included. Excision of high‐risk tumours with margin assessment was recommended in all guidelines. A safety margin of at least 6 mm was suggested in four guidelines. There was no clear recommendation to perform a sentinel lymph node biopsy in any guideline. Lymph node dissection was uniformly recommended in the presence of nodal disease. Treatment for metastatic cSCC was poorly characterized and restricted to the use of chemotherapy and epidermal growth factor receptor inhibitors. Recommendations for the management of high‐risk and advanced cSCC were limited. We propose that guidelines should be updated to reflect recent advances in checkpoint blockade for metastatic cSCC

SIRTF Telescope Instrument Changeout and Cryogen Replenishment (STICCR) Study

The Space Infrared Telescope Facility (SIRTF) is a long-life cryogenically cooled space-based telescope for infrared astronomy from 2 to 700 micrometers. SIRTF is currently under study by NASA-ARC (Reference AP) and planned for launch in approximately the mid 1990s. SIRTF will operate as a multiuser facility, initially carrying three instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and baseline is currently to be 2 years. The telescope changes required to allow in-space replenishment of the 4,000-L superfluid helium tank was investigated. A preliminary design for the space services equipment was also developed. The impacts of basing the equipment and servicing on the space station were investigated. Space replenishment and changeout of instruments required changes to the telescope design. Preliminary concepts are presented

Investigation of external refrigeration systems for long term cryogenic storage Final report

Data on external refrigeration systems for space storage of cryogens for long period

Investigation of external refrigeration systems for long-term cryogenic storage

Evaluation of cryogenic refrigeration systems for space application

Handbook of external refrigeration systems for long term cryogenic storage

Handbook of external refrigeration systems for long term cryogenic storag