Evaluation of the electrochemical O2 concentrator as an O2 compressor

A program was successfully completed to analytically and experimentally evaluate the feasibility of using an electrochemical oxygen (O2) concentrator as an O2 compressor. The electrochemical O2 compressor (EOC) compresses 345 kN/sq m (50 psia) O2 generated on board the space vehicle by the water electrolysis subsystem (WES) in a single stage to 20,700 kN/sq m (3000 psia) to refill spent extravehicular equipment O2 bottles and to eliminate the need for high pressure O2 storage. The single cell EOC designed, fabricated, and used for the feasibility testing is capable of being tested at O2 pressures up to 41,400 kN/sq m (6000 psia). A ground support test facility to test the EOC cell was designed, fabricated, and used for the EOC feasibility testing. A product assurance program was established, implemented, and maintained which emphasized safety and materials compatibility associated with high pressure O2 operation. A membrane development program was conducted to develop a membrane for EOC application. Data obtained using a commercially available membrane were used to guide the development of the membranes fabricated specifically for an EOC. A total of 15 membranes were fabricated

An experimental study of the buckling of complete spherical shells

Buckling of complete spherical shells to examine Tsien energy hypothesi

Electrochemical carbon dioxide concentrator: Math model

A steady state computer simulation model of an Electrochemical Depolarized Carbon Dioxide Concentrator (EDC) has been developed. The mathematical model combines EDC heat and mass balance equations with empirical correlations derived from experimental data to describe EDC performance as a function of the operating parameters involved. The model is capable of accurately predicting performance over EDC operating ranges. Model simulation results agree with the experimental data obtained over the prediction range

Electrochemical carbon dioxide concentrator subsystem math model

A steady state computer simulation model has been developed to describe the performance of a total six man, self-contained electrochemical carbon dioxide concentrator subsystem built for the space station prototype. The math model combines expressions describing the performance of the electrochemical depolarized carbon dioxide concentrator cells and modules previously developed with expressions describing the performance of the other major CS-6 components. The model is capable of accurately predicting CS-6 performance over EDC operating ranges and the computer simulation results agree with experimental data obtained over the prediction range

Quantum Monte Carlo Calculations of A≤6A\leq6 Nuclei

The energies of $^{3}H$, $^{3}He$, and $^{4}He$ ground states, the ${\frac{3}{2}}^{-}$ and ${\frac{1}{2}}^{-}$ scattering states of $^{5}He$, the ground states of $^{6}He$, $^{6}Li$, and $^{6}Be$ and the $3^{+}$ and $0^{+}$ excited states of $^{6}Li$ have been accurately calculated with the Green's function Monte Carlo method using realistic models of two- and three-nucleon interactions. The splitting of the $A=3$ isospin $T=\frac{1}{2}$ and $A=6$ isospin $T=1$, $J^{\pi} = 0^{+}$ multiplets is also studied. The observed energies and radii are generally well reproduced, however, some definite differences between theory and experiment can be identified.Comment: 12 pages, 1 figur

Spacecraft nitrogen generation

Two spacecraft nitrogen (N2) generation systems based on the catalytic dissociation of hydrazine (N2H4) were evaluated. In the first system, liquid N2H4 is catalytically dissociated to yield an N2 and hydrogen (H2) gas mixture. Separation of the N2/H2 gas mixture to yield N2 and a supply of H2 is accomplished using a polymer-electrochemical N2/H2 separator. In the second system, the N2/H2 gas mixture is separated in a two-stage palladium/silver (Pd/Ag) N2/H2 separator. The program culminated in the successful design, fabrication, and testing of a N2H4 catalytic dissociator, a polymer-electrochemical N2/H2 separator, and a two-stage Pd/Ag N2/H2 separator. The hardware developed was sized for an N2 delivery rate of 6.81 kg/d (15lb/day). Experimental results demonstrated that both spacecraft N2 generation systems are capable of producing 6.81 kg/d (15lb/day) of 99.9% pure N2 at a pressure greater than or equal to 1035 kN/m(2) (150 psia)

IWR; no. 96

A report of a workshop held at The University of Alberta, Edmonton on March 20, 1978.The Joint Canadian-United States Northern Civil Engineering Research Workshop was held at the University of Alberta campus, Edmonton, Alberta on March 20 through 22, 1978. Over 40 participants from government, universities, and private practice from both the U.S. and Canada discussed northern civil engineering research for 2 1/2 days. The results of their effort are presented in this report. The nature of a report coming from spontaneous conversation will be somewhat uneven in coverage, language, and tone. However, we feel obligated to preserve the initial intent and language of the various workshop groups and each report should represent the original conclusion as nearly as possible. We acted as the principal instigators of the workshop and were ably assisted by an excellent group of workshop chairmen: Jack Clark, Lorne Gold, Charles Neill, Daniel Rogness, James Rooney, and Daniel Smith. We particularly want to acknowledge the assistance of the Boreal Institute for organizing and providing much of the administrative and secretarial support for the workshop, and the staff of the Institute of Water Resources for assisting with the organizing and publication processes. The workshop was sponsored by the National Science Foundation of the United States, the Department of Indian and Northern Affairs of Canada, the Boreal Institute and Department of Civil Engineering of the University of Alberta, and the Institute of Water Resources of the University of Alaska. R. F. Carlson N. R. MorgensternNSF Grant No. ENG 76-22293 Department of Indian and Northern Affairs Grant 64-0502

Ab initio calculation of the electromagnetic and neutral-weak response functions of 4He and 12C

Precise measurement of neutrino oscillations, and hence the determination of their masses demands a quantitative understanding of neutrino-nucleus interactions. To this aim, two-body meson-exchange currents have to be accounted for along within realistic models of nuclear dynamics. We summarize our progresses towards the construction of a consistent framework, based on quantum Monte Carlo methods and on the spectral function approach, that can be exploited to accurately describe neutrino interactions with atomic nuclei over the broad kinematical region covered by neutrino experiments.Comment: 8 pages, 4 figure, Proceedings of the 21st International Conference on Few-Body Problems in Physics, Chicago, Illinois, US

Masses of the 70- Baryons in Large Nc QCD

The masses of the negative parity 70-plet baryons are analyzed in large N_c QCD to order 1/N_c and to first order in SU(3) symmetry breaking. The existing experimental data are well reproduced and twenty new observables are predicted. The leading order SU(6) spin-flavor symmetry breaking is small and, as it occurs in the quark model, the subleading in 1/N_c hyperfine interaction is the dominant source of the breaking. It is found that the Lambda(1405) and Lambda(1520) are well described as three-quark states and spin-orbit partners. New relations between splittings in different SU(3) multiplets are found.Comment: 11 pages; references were added and a couple of improvements to the text were mad