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At least 649 records · Page 36

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NASA NTRS1973

Study to validate the Non-Interference Performance Assessment (NIPA) technique

The NIPA (Non-Interference Performance Assessment) technique involves direct observation of group verbal activities by trained observers who rate the emotional content (affect) of each verbal interaction as either positive, negative, or neutral. During the test, in which four men were confined for 90 consecutive days, feasibility of the NIPA technique was demonstrated and observer reliability was verified. However, the validity of the test was not proved because an independent criterion measure of morale for the confined crew was lacking. There were indications, however, that NIPA measures were tracking changes in crew morale. At approximately the two-thirds point (Days 60 to 70), morale apparently fell dramatically for a period of about ten days, and simultaneously NIPA measure of positive verbalization decreased in number. A need was indicated for a separate study to apply the NIPA technique under experimental conditions and using a clearly defined criterion measure against which the ability of NIPA observations to truly measure morale changes could be determined.

Seeman, J. S.↗

NASA NTRS1973

Boundary lubrication of formulated C-ethers in air to 300 C. 2: Organic acid additives

Friction and wear measurements were made on CVM M-50 steel lubricated with three C-ether (modified polyphenyl ether) formulations in dry and moist air. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, a 17-meter/minute surface speed, and a 25 to 300 C (77 to 572 F) disk temperature range. The three C-ether formulations yielded better boundary lubricating characteristics than the Type 2 ester under most test conditions. All C-ether formulations exhibited higher friction coefficients than the ester from 150 to 300 C (302 to 572 F) and similar or lower values from 25 to 150 C (77 to 302 F).

Jones, W. R., Jr.↗

NASA NTRS1973

Thermal conductivity of particulate materials: A summary of measurements taken at the Marshall Space Flight Center

Thermal conductivity measurements of particulate materials in vacuum are presented in summary. Particulate basalt and soda lime glass beads of various size ranges were used as samples. The differentiated line heat source method was used for the measurements. A comprehensive table is shown giving all pertinent experimental conditions. Least-squares curve fits to the data are presented.

Fountain, J. A.↗

NASA NTRS1973

Atom beam surface interaction studies: Experimental system development

Quantitative deposition by standard techniques of adsorbates containing C and Si onto selected substrates is studied. The interaction kinetics of a beam of oxygen, nitrogen, or hydrogen atoms of known flux are investigated by Auger electron spectroscopy and LEED. Desborbed molecules will be analyzed by mass spectroscopy using modulated beam techniques. Experimental conditions permitting, two sets of measurements will be correlated.

Gregory, J. C.↗

NASA NTRS1973

Artificial meteor ablation studies: Olivine

Artificial meteor ablation was performed on a Mg-rich olivine sample using an arc-heated plasma of ionized air. Experimental conditions simulated a meteor traveling about 12 km/sec at an altitude of 70 km. The mineral content of the original olivine sample was 98% olivine (including traces of olivine alteration products) and 2% chromite. Forsterite content of the original olivine was Fo-89. After ablation, the forsterite content had increased to Fo-94 in the recrystallized olivine. In addition, lamella-like intergrowths of magnetite were prevalent constituents. Wherever magnetite occurred, there was an increase in Mg and a corresponding decrease in Fe for the recrystallized olivine. The Allende fusion crust consisted of a recrystallized olivine, which was more Mg-rich and Fe-deficient than the original meteorite's olivine, and abundant magnetite grains. Although troilite and pentlandite were the common opaque mineral constituents in this meteorite, magnetite was the principal opaque mineral found in the fusion crust.

Blanchard, M. B.↗

NASA NTRS1973

Anti-motion-sickness therapy

Neither alterations in environmental temperature nor moderate intake of alcohol was found to alter susceptibility to motion sickness in subjects exposed to rotation in the Pensacola slow rotation room. Scopolamine with d-amphetamine was found to be the most effective preparation for the prevention of motion sickness under the experimental conditions of the studies reported here. Promethazine in combination with d-amphetamine was in the same range of effectiveness. Drug actions suggest that acetylcholine and norepinephrine may be involved in motion sickness.

Wood, C. D.↗

NASA NTRS1973

Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components

The mechanism for thermal inactivation of bacterial spores under moist or dry heat was studied. Experimental conditions were established relating to spore loss of heat resistance and loss of optical density as a measure of the rate and extent of germination in spore suspensions. Events occurring during germination were correlated with phase darkening (refractility and non-refractility of spores), stainability characteristics of heat and non-heat treated spores, morphological characteristics, and studies on swelling of spores by an increase in packed cell volume.

Campbell, J. E.↗

NASA NTRS1973

Study to design and develop remote manipulator system

Human performance measurement techniques for remote manipulation tasks and remote sensing techniques for manipulators are described for common manipulation tasks, performance is monitored by means of an on-line computer capable of measuring the joint angles of both master and slave arms as a function of time. The computer programs allow measurements of the operator's strategy and physical quantities such as task time and power consumed. The results are printed out after a test run to compare different experimental conditions. For tracking tasks, we describe a method of displaying errors in three dimensions and measuring the end-effector position in three dimensions.

Hill, J. W.↗

NASA NTRS1974

Test techniques for obtaining off-nominal compressor data during engine tests

Several unique techniques and related devices are described which are in use at the Lewis Research Center for off-design testing of fan and compressor sections in full-scale jet engines. The devices presented permit a wide range of experimental conditions and minimize downtime for hardware changes. The techniques involve use of such devices as inlet pressure distortion jets, a hydrogen burner for inlet temperature distortions, fan back pressure jets to simulate a variable area nozzle, and either an inflow-outflow bleed system or a fuel spurt system to alter compressor discharge pressure.

Biesiadny, T. J.↗

NASA NTRS1973

Cautionary note concerning the CuSO4 X-ray laser

For the so far unconfirmed lasing action claimed by Kepros et al. (1972) to have been obtained by focusing a 1.06-micron radiation of a q-switched Nd(3+) glass laser to a small cylindrical volume inside a CuSO4-doped gelatin medium supported between two glass plates, an alternate explanation is proposed that does not depend on the assumption of laser action in copper. The proposed explanation shows how collimated X-ray beams might be created under the experimental conditions described by Kepros et al.

Billman, K. W.↗

NASA NTRS1973

Surface segregation in titanium as monitored by Auger electron spectroscopy

Investigation of the surface diffusion and segregation of bulk impurities in titanium single crystals under well-defined and controlled experimental conditions. It is shown that an atomically clean titanium single-crystal surface can be obtained by argon ion bombardment within the temperature range from 700 to 800 C. It is demonstrated by Auger electron spectroscopy that, if such clean surfaces are subjected to thermal treatment, bulk impurities, especially sulfur, diffuse out to the crystal surface, and that the rate of surface segregation increases with increasing temperature.

Khan, I. H.↗

NASA NTRS1974

Automated life-detection experiments for the Viking mission to Mars

As part of the Viking mission to Mars in 1975, an automated set of instruments is being built to test for the presence of metabolizing organisms on that planet. Three separate modules are combined in this instrument so that samples of the Martian surface can be subjected to a broad array of experimental conditions so as to measure biological activity. The first, the Pyrolytic Release Module, will expose surface samples to a mixture of C-14O and C-14O2 in the presence of Martian atmosphere and a light source that simulates the Martian visible spectrum. The assay system is designed to determine the extent of assimilation of CO or CO2 into organic compounds. The Gas Exchange Module will incubate surface samples in a humidified CO2 atmosphere. At specified times, portions of the incubation atmosphere will be analyzed by gas chromatography to detect the release or uptake of CO2 and several additional gases. The Label Release Module will incubate surface samples with a dilute aqueous solution of simple radioactive organic substrates in Martian atmosphere, and the gas phase will be monitored continuously for the release of labeled CO2.

Klein, H. P.↗

NASA NTRS1974

Specimen analysis of the Skylab M553 Metals Melting and Solidification Experiment

The M553 Sphere Forming Experiment conducted in the M512 Furnace Facility during Skylab II was designed to study the effects of weightlessness on the solidification process. Results indicated that there was an outstanding record of solidification terracing and solute redistribution, and that this record may be better than obtainable terrestrially. The solute redistribution was found to be highly localized to prescribed crystallographic systems. It was also shown that for some experimental conditions in a space environment, the anticipated solid/liquid solidification process was perturbed and a solid/liquid/gas reaction took place during solidification. It is felt that these results will contribute to the understanding of terrestrial solidification and will contribute to future space processing considerations.

Larson, D., Jr.↗

NASA NTRS1974

Artificial meteor ablation studies - Olivine

Artificial meteor ablation has been performed on a Mg-rich olivine sample by means of an arc-heated plasma of ionized air. Experimental conditions simulated a meteor traveling about 12 km/sec at an altitude of 70 km. The mineral content of the original olivine was 98% olivine (including traces of olivine alteration products) and 2% chromite. The forsterite content of the original olivine was Fo 89 and increased to Fo 94 in the recrystallized olivine after ablation. In addition, lamella-like intergrowths of magnetite were prevalent. Wherever magnetite occurred, Mg increased and Fe decreased in the recrystallized olivine. The Fe for the magnetite exsolved from the original olivine crystals. Individual particles (i.e., spherules) were also characterized by magnetite intergrowths. Fusion crusts on the Allende and Murchison meteorites were compared with the fusion crust on the olivine sample. The Allende fusion crust consisted of a recrystallized olivine, richer in Mg and deficient in Fe in comparison with the original meteorite's olivine, and abundant magnetite grains.

Blanchard, M. B.↗

NASA NTRS1975

Design of experiments for measuring heat-transfer coefficients with a lumped-parameter calorimeter

A theoretical investigation was conducted to determine optimum experimental conditions for using a lumped-parameter calorimeter to measure heat-transfer coefficients and heating rates. A mathematical model of the transient temperature response of the calorimeter was used with the measured temperature response to predict the heat-transfer coefficient and the rate of heating. A sensitivity analysis was used to determine the optimum transient experiment for simultaneously measuring the heat addition during heating and the convective heat-transfer coefficient during heating and cooling of a lumped-parameter calorimeter. Optimum experiments were also designed for measuring the convective heat-transfer coefficient during both heating and cooling and cooling only.

Vanfossen, G. J., Jr.↗

NASA NTRS1975

Boundary lubrication of formulated C-ethers in air to 300 C

Friction and wear measurements were made in dry and moist air on CVM M-50 steel lubricated with six C-ether formulations containing phosphorus ester and organic acid additives. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, 17 meter-per-minute (100 rpm) surface speed, and a 25 to 300 C disk temperature range. The C-ether base fluid and the C-ether formulations yielded lower wear than the ester under most test conditions. The C-ether formulations exhibited higher friction coefficients than the ester from 150 to 300 C and similar or lower values from 25 to 150 C.

Jones, W. R., Jr.↗

NASA NTRS1975

Significance of biorhythms in space flight

Evidence is presented that the most important factor in the maintenance of optimal health and performance is the stability of the relationship of one body rhythm to another. The effect of social interaction on performance, well-being, and physiological rhythm synchrony was investigated. Three groups of healthy males, ages 21 to 25, were confined in rooms (3.4 by 5.2 meters (11 by 17 feet)) for a total period of 105 days. Two of the groups were in rooms in which the environment could be regulated. The third group served as the control group and was exposed to ambient experimental conditions. The confined subjects were exposed for periods to several days either to 16 hours of light and 8 hours of dark, or to continuous light at a light intensity of 161 lm/sq m (15 foot-candles). The confined subjects were deprived of all time cues, and meals were ad libitum. The subjects were observed throughout the study by a video camera and were scored for activity. Communications were limited to meal and sample-collection information, and meals and samples were passed through a two-way hatch. Rectal temperature and heart rate (HR) were sampled every 30 minutes by telemetry throughout the study. Results are presented.

Winget, C. M.↗

NASA NTRS1975

A nonlinear model for gas chromatograph systems

Fundamental engineering design techniques and concepts were studied for the optimization of a gas chromatograph-mass spectrometer chemical analysis system suitable for use on an unmanned, Martian roving vehicle. Previously developed mathematical models of the gas chromatograph are found to be inadequate for predicting peak heights and spreading for some experimental conditions and chemical systems. A modification to the existing equilibrium adsorption model is required; the Langmuir isotherm replaces the linear isotherm. The numerical technique of Crank-Nicolson was studied for use with the linear isotherm to determine the utility of the method. Modifications are made to the method eliminate unnecessary calculations which result in an overall reduction of the computation time of about 42 percent. The Langmuir isotherm is considered which takes into account the composition-dependent effects on the thermodynamic parameter, mRo.

Feinberg, M. P.↗