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At least 1,675 records · Page 93

Solar wind for a magnetized plasma with tensor plasma pressure.

A solar wind model for a magnetized solar wind is presented using one-fluid hydromagnetic equations with generalized polytrope equations of state for the two tensor components of the plasma pressure. Fluid and magnetic field variables are calculated at the Earth using certain boundary conditions at the Sun. The azimuthal velocity agrees with observed values and explains the considerable loss of angular momentum from the Sun by the solar wind. The results are good for most variables but suggest that a two-fluid model with electrons at higher temperatures and smaller temperature anisotropy ratios than the ions would give improved agreement for some quantities.

Tan, M.↗

Evaluation of 165 deg F reverse osmosis modules for washwater purification.

Three membrane systems have been evaluated for concentration at 165 F of wash-water contaminants. Membranes tested are polybenzimidazole (hollow fibers), cellulose acetate blend (spiral wound), and sulfonated polyphenylene oxide (plate-and-frame). Detailed membrane flux and rejection data are presented for 200-hr life tests with synthetic wash water, at two concentrations, and real wash water, at one concentration. Advantages and limitations of the membrane configurations, are discussed.

Hossain, S.↗

Water vapor diffusion membrane development

The phase separator component used as a membrane in the vapor diffusion process (VRD) for the recovery of potable water from urine on manned space missions of extended duration was investigated, with particular emphasis on cation-selective membranes because of their noted mechanical strength, superior resistance to acids, oxidants, and germicides, and their potential resistance to organic foulants. Two of the membranes were tested for 700 hours continuously, and were selected on the basis of criteria deemed important to an effective water reclamation system onboard spacecraft. The samples of urine were successfully processed by removing 93 percent of their water content in 70 hours using the selected membranes. Pretreatment with an acid-oxidant formulation improved product quality. Cation exchange membranes were shown to possess superior mechanical strength and chemical resistance, as compared to cellulosic membranes.

Tan, M. K.↗

Water vapor diffusion membrane development

A total of 18 different membranes were procured, characterized, and tested in a modified bench-scale vapor diffusion water reclamation unit. Four membranes were selected for further studies involving membrane fouling. Emphasis was placed on the problem of flux decline due to membrane fouling. This is discussed in greater details under "Summary and Discussion on Membrane Fouling Studies" presented in pages 47-51. The system was also investigated for low temperature application on wash-water where the permeated water is not recovered but vented into space vacuum.

Tan, M. K.↗

Ionization effects due to solar flare on terrestrial ionosphere

Sudden frequency deviation ionospheric disturbances related to the flares of May 18 and 19, 1973 were observed from the NASA/MSFC high frequency Doppler sounder array system in Huntsville, Alabama. The results are compared with those observed at Table Mountain near Boulder, Colorado and at the University of Hawaii.

Wu, S. T.↗