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Payne, P. A.

Publications and source records attributed to Payne, P. A..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Cardiovascular responses of men and women to lower body negative pressure

Changes in blood flow and blood redistribution were measured by impedance plethysmography in the pelvic and leg regions of six male and four female subjects during three 5-min exposures to -20, -40, and -60 mm Hg lower body negative pressure (LBNP). Female subjects demonstrated significantly higher mean heart rate and lower leg blood flow indices than the male subjects during the recumbent control periods. Men had slightly higher mean resting systolic and diastolic blood pressures and higher mean control pelvic blood indices. Women demonstrated significantly less blood pooling in the legs and slightly less in the pelvic region than the men. All of the 18 tests with male subjects at -60 mm Hg were completed without initial signs of syncope, while only two of the tests with women were completed successfully without the subject exhibiting presyncopal conditions. Results indicate that impedance plethysmography can be used to measure segmental cardiovascular responses during LBNP and that females may be less tolerant to -60 mm Hg LBNP than males.

Montgomery, L. D.↗
NASA NTRS1973

New system for bathing bedridden patients

Multihead shower facility can be used with minimal patient handling. Waterproof curtain allows patient to bathe with his head out of shower. He can move completely inside shower to wash his face and hair. Main advantage of shower system is time saved in giving bath.

Greenleaf, J. E.↗
NASA NTRS1972

Development and pilot line production of lithium doped silicon solar cells

The work performed over the period of September 1971 to August 1972 to develop production processes for fabrication of lithium doped P/N cells is described. The BCl3 diffusion without 02 was selected as the optimum diffusion process for fabrication of lithium doped cells. An 8-2-7 (warm up - deposition - drive-in time in minutes) diffusion schedule at 1055 C was used for the first two lots (300 cells each) delivered to JPL. Cell efficiencies ranged from 11.0 to 13.7% based on an AMO of 135.3 mW/sq cm. These high efficiencies were obtained using from 10 to 40 cells per boron diffusion; increasing the quantity beyond 40 resulted in lower outputs. At this point, the emphasis was placed on investigation of a BCl3 with 02 diffusion. Through evaluation of the effects of diffusion time and temperature, gas flow rates, and desposition plus drive-in vs. continuous deposition and no drive-in cycles, diffusion parameters were determined which produced short circuit currents of 136 + or - 4 mA for ten cells spaced along 12 in. of the diffusion boat. The quantity was increased to 60, 100, and 150 cell diffusions with no more variation in cell short circuit current than observed with 10 cells.

Payne, P. A.↗
NASA NTRS1972

Development and pilot line production of lithium doped silicon solar cells

Scaling up the BCl3 without O2 diffusion beyond 30 to 40 cells was investigated by using a 100 cell capacity diffusion boat which held the cells vertically. Sheet resistances and I-V curves were uniform with 10 to 20 cells spaced along the entire boat, so the quantity was increased to 40 and then 60 cells per diffusion. There was no change in cell output and uniformity going from 20 to 40 cells per diffusion; however only half the lithium cells fabricated from slices diffused in the 60 cell diffusion had efficiencies of 11% or better. Although uniform sheet resistances and I-V characteristic curves were obtained with up to 60 cells in the BCl3 with O2 diffusion, the short circuit currents were approximately 15% lower than the anticipated 135 to 140 mA. Consequently, work on this diffusion process has been aimed solely at increasing the short circuit current. The diffusion temperature was lowered from 1055 to 1000 and 950 C, and at each of these temperatures variations in diffusion time were investigated. At 1000 C short circuit currents were approximately 10 mA higher, 130 rather than 120 mA average.

Payne, P. A.↗
NASA NTRS1972

Research and development of silicon solar cells for low solar intensity and low temperature applications

Problems were identified, using N/P solar cells at low temperature and low intensity; these problems were solved and the solutions incorporated in a manufacturing procedure. Theoretical analysis of the effects of low temperature and low intensity on the various solar cell characteristics indicated that the following behavior might be expected: (1) lower short circuit current,(2) higher open circuit voltage,(3) series resistance becoming less significant, and (4) shunt resistance becoming more critical.

Payne, P. A.↗
NASA NTRS1971

Lithium-doped solar cells for space use

Lithium doped p-n solar cells meet the basic requirements for space use. The efficiencies of the Lopex lithium cells which range from 10.5 to 12.8% are equal to or better than C.G. lithium cell and 10 ohms-cm n-p cell efficiencies. Reduction in the stresses introduced during boron diffusion has eliminated cell size restrictions and both 2 x 2 and 2 x 6 cm lithium doped cells have been fabricated. The Ti-Ag contacts which are tested 100% with a tape peel test, and pull tested and humidity tested on a sample basis are comparable to the Ti-Ag contacts on n-p cells.

Payne, P. A.↗