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Thermal insulating capabilities of outdoor clothing materials (1982)

W. C. Kaufman ; D. Bothe ; S. D. Meyer

American Association for the Advancement of Science (AAAS)

In: Science. 215(4533): 690-1. doi: 10.1126/science.215.4533.690.

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Publication Date: 1982-02-05

Description: A single heat transfer measurement technique was used to determine the thermal insulating capabilities of four materials used in outdoor clothing-goose down, wool, polyester, and polyolefin. It was found that all provide very similar degrees of insulation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kaufman, W C -- Bothe, D -- Meyer, S D -- New York, N.Y. -- Science. 1982 Feb 5;215(4533):690-1.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17842404" target="_blank"〉PubMed〈/a〉

Print ISSN: 0036-8075

Electronic ISSN: 1095-9203

Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics

Published by American Association for the Advancement of Science (AAAS)

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CO2 leakage alters biogeochemical and ecological functions of submarine sands (2018)

Molari, M., Guilini, K., Lott, C., Weber, M., de Beer, D., Meyer, S., Ramette, A., Wegener, G., Wenzhöfer, F., Martin, D., Cibic, T., De Vittor, C., Vanreusel, A., Boetius, A.

American Association for the Advancement of Science (AAAS)

In: Science Advances

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Publication Date: 2018-02-09

Description: Subseabed CO 2 storage is considered a future climate change mitigation technology. We investigated the ecological consequences of CO 2 leakage for a marine benthic ecosystem. For the first time with a multidisciplinary integrated study, we tested hypotheses derived from a meta-analysis of previous experimental and in situ high-CO 2 impact studies. For this, we compared ecological functions of naturally CO 2 -vented seafloor off the Mediterranean island Panarea (Tyrrhenian Sea, Italy) to those of nonvented sands, with a focus on biogeochemical processes and microbial and faunal community composition. High CO 2 fluxes (up to 4 to 7 mol CO 2 m –2 hour –1 ) dissolved all sedimentary carbonate, and comigration of silicate and iron led to local increases of microphytobenthos productivity (+450%) and standing stocks (+300%). Despite the higher food availability, faunal biomass (–80%) and trophic diversity were substantially lower compared to those at the reference site. Bacterial communities were also structurally and functionally affected, most notably in the composition of heterotrophs and microbial sulfate reduction rates (–90%). The observed ecological effects of CO 2 leakage on submarine sands were reproduced with medium-term transplant experiments. This study assesses indicators of environmental impact by CO 2 leakage and finds that community compositions and important ecological functions are permanently altered under high CO 2 .

Electronic ISSN: 2375-2548

Topics: Natural Sciences in General

Published by American Association for the Advancement of Science (AAAS)

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Evaluation of a hybrid hydrostatic bearing for cryogenic turbopump application (1986)

Hannum, N. P. ; Spica, P. W. ; Meyer, S. D.

In: CASI

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Publication Date: 2019-06-28

Description: A hybrid hydrostatic bearing was designed to operate in liquid hydrogen at speeds to 80,000 rpm and radial loads to 440 n (100 lbf). The bearing assembly consisted of a pair of 20-mm angular-contact ball bearings encased in a journal, which was in turn supported by a fluid film of liquid hydrogen. The size and operating conditions of the bearing were selected to be compatible with the operating requirements of an advanced technology turbopump. Several test parameters were varied to characterize the bearing's steady-state operation. The rotation of the tester shaft was varied between 0 and 80,000 rpm. Bearing inlet fluid pressure was varied between 2.07 and 4.48 MPa (300 and 650 psia), while the fluid sump pressure was independently varied between 0.34 and 2.07 MPa (50 and 300 psia). The maximum radial load applied to the bearing was 440 N (110 lbf). Measured hybrid-hydrostatic-bearing stiffness was 1.5 times greater than predicted, while the fluid flow rate through the bearing was 35 to 65 percent less than predicted. Under two-phase fluid conditions, the stiffness was even greater and the flow rate was less. The optimal pressure ratio for the bearing should be between 0.2 and 0.55 depending on the balance desired between bearing efficiency and stiffness. Startup and shutdown cyclic tests were conducted to demonstrate the ability of the hybrid-hydrostatic-bearing assembly to survive at least a 300-firing-duty cycle. For a typical cycle, the shaft was accelerated to 50,000 rpm in 1.8 sec. The bearing operated for 337 start-stop cycles without failure.

Keywords: SPACECRAFT PROPULSION AND POWER

Type: NASA-TM-87255 , E-2945 , NAS 1.15:87255

Format: application/pdf

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