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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Magnitude of 64-m elevation axis movements due to alidade temperature changes

In projected very-long baseline interferometry (VLBI) work a reference point for 64-m antennas is the intersection of the elevation and azimuth axes. A minimum-level effort at DSS 14 to determine the magnitude of the effect of diurnal changes in the temperature of the alidade legs on the height of the elevation axis is described. The thermal expansion between the lowest recorded temperature -3 C (27 F) and the highest, 36 C (97 F), over the period covered was 8.9 mm (0.35 in.).

Hung, N. T.↗
NASA NTRS1976

Biomedical technology transfer: Bioinstrumentation for cardiology, neurology, and the circulatory system

Developments in applying aerospace medical technology to the design and production of medical equipment and instrumentation are reported. Projects described include intercranial pressure transducers, leg negative pressure devices, a synthetic speech prosthesis for victims of cerebral palsy, and a Doppler blood flow instrument. Commercialization activities for disseminating and utilizing NASA technology, and new biomedical problem areas are discussed.

Source record↗
NASA NTRS1977

Coastal wave measurements during passage of tropical storm Amy

Aerial photographic and laser profilometer data of waves generated by tropical storm Amy are presented. The data mission consisted primarily of two legs, one in the direction of the wind waves, and the second along the direction of swell propagation, using Jennette's Pier at Nags Head, North Carolina, as a focal point. At flight time, Amy's center was 512 nmi from shore and had maximum winds of 60 knots. The storm's history is presented, along with a satellite photograph, showing the extent of the storm on the day of the flight. Flight ground tracks are presented along with sample aerial photographs of the wave conditions showing approximate wavelength and direction. Sample wave energy spectra are presented both from the laser profilometer onboard the aircraft, and from the Corps of Engineers Research Center (CERC) shore gauge at Nags Head, North Carolina.

Morris, W. D.↗
NASA NTRS1977

Skylab 2 crew observations and summary

Signs and symptoms experienced during weightlessness ranged from a sensation of fullness in the head to a strange body posture and the sensation of fluid drainage out of the legs. There was no vestibular sense of the upright whatsoever unless the crewmember happened to look at the earth; motion sickness was not a clinical problem. The ability to maintain physical fitness through exercise and the caloric demand remained just about the same as they do on the ground after initial adjustment.

Kerwin, J. P.↗
NASA NTRS1977

Biostereometric analysis of body form

Four-camera stereophotogrammetry of Skylab crewmen, preflight and postflight, revealed a loss of volume of one to one and one-half liters from the legs, much of which was replaced during the first 4 postflight days. It is estimated that about one third of the loss represents partial atrophy due to relative disuse in zero-gravity, the remainder being due to a deficit in body fluid. Reduction in volume of the abdomen has also been noted.

Whittle, M. W.↗
NASA NTRS1977

Evaluation of the electromechanical properties of the cardiovascular system after prolonged weightlessness

Devices and techniques for measuring and analyzing systolic time intervals and quantitative phonocardiograms were initiated during Apollo 17. The data show that the systolic time interval from Apollo 17 crewmen remained elevated longer postflight than the response criteria of heart rate, blood pressure, and percent change in leg volume all of which had returned to preflight levels by the second day postflight. Although the systolic time interval values were only slightly outside the preflight fiducial limits, this finding suggested that: the analysis of systolic time intervals may help to identify the mechanisms of postflight orthostatic intolerance by virtue of measuring ventricular function more directly and, the noninvasive technique may prove useful in determining the extent and duration of cardiovascular instability after long duration space flight. The systolic time intervals obtained on the Apollo 17 crewmen during lower body negative pressure were similar to those noted in patients with significant heart disease.

Bergman, S. A., Jr.↗
NASA NTRS1977

Exerciser

The Mark I exerciser which was added for the second and third Skylab missions, was used for a number of arm and leg exercises. This unit is a modified version of a commercial device. This is an iso-kinetic, or constant velocity, exerciser which retards the speed at which the user is allowed to move. The user applies a maximum effort and the device automatically varies the opposing resistance to maintain speed of translation at a constant preselected value.

Lem, J. D.↗
NASA NTRS1977

Labyrinth and cerebral-spinal fluid pressure changes in guinea pigs and monkeys during simulated zero G

This study was undertaken to explore the hypothesis that shifts of body fluids from the legs and torso toward the head contribute to the motion sickness experienced by astronauts and cosmonauts. The shifts in body fluids observed during zero-G exposure were simulated by elevating guinea pigs' and monkeys' torsos and hindquarters. Cerebral-spinal fluid pressure was recorded from a transducer located in a brain ventricle; labyrinth fluid pressure was recorded from a pipette cemented in a hole in a semicircular canal. An anticipated divergence in cerebral-spinal fluid pressure and labyrinth fluid pressure during torso elevation was not observed. The results of this study do not support a fluid shift mechanism of zero-G-induced motion sickness. However, a more complete test of the fluid shift mechanism would be obtained if endolymph and perilymph pressure changes were determined separately; we have been unable to perform this test to date.

Parker, D. E.↗
NASA NTRS1977

Planetary atmospheres with mass spectrometers carried on high-speed probes or satellites

Earth satellite-borne mass spectrometers are considered, taking into account the identification of atomic oxygen in the thermosphere with an 'open' source mass spectrometer flown on a sounding rocket, the conventional closed-source instrument, the mass spectrometers on the Atmosphere Explorer satellites, and mass spectrometer electron multiplier output. A description is presented of mass spectrometers and planetary entry probes. Attention is given to an attempt to obtain an atmospheric composition profile with a terrestrial entry probe, the descending trajectory in the early orbits of the Atmosphere Explorer C satellite, and the molecular nitrogen densities for the descending legs of the orbits. It is pointed out that chemical reactions on the surfaces of the mass spectrometer make the measurement of reactive atmospheric species such as atomic oxygen very difficult.

Nier, A. O.↗
NASA NTRS1977

Propulsion cycle effects for a two-fan V/STOL aircraft

This paper discusses the results of an in-depth study investigating the impacts of variable pitch, geared turbofan cycle parameters on a two-fan, subsonic, V/STOL aircraft. Variations in fan pressure ratio, compressor pressure ratio and combustor exit temperature are presented as they affect critical mission legs, aircraft performance, engine thrust-to-weight ratio and as a total systems impact in terms of aircraft takeoff gross weight. Several parameters have counter acting components which, when combined, synergistically result in an optimum value for that parameter. Careful attention has been paid to the changes in aircraft installation penalties associated with each cycle parameter.

Feddersen, R. E.↗
NASA NTRS1977

Low Reynolds number flow past a blunt axisymmetric body at angle of attack

Low Reynolds number flow of an ideal gas over a blunt axisymmetric body of large half-angle at small angles of attack is investigated, for the case of laminar hypersonic flow. Time-varying viscous shock layer equations describing the flowfield are obtained from the full Navier-Stokes system by keeping terms to second order in the inverse square root of Re in both viscous and inviscid regions; the equations are valid for moderate to high Re. Drag, skin friction, and heating rates were obtained at small (or zero) angles of attack. Conditions experienced by planetary entry probes during the high-altitude (early) legs of an atmospheric entry trajectory are pertinent to the problem.

Kumar, A.↗
NASA NTRS1977

Extension of atomic nitrogen measurements into the lower thermosphere

Special operating modes of the open source neutral mass spectrometer (OSS) on the Atmosphere Explorer C permit the measurement of odd nitrogen (N + NO) number densities between 180 and 450 km. By using optical measurements of NO concentrations from the ultraviolet nitric oxide experiment on AE-C, number densities of N are obtained. Altitude profiles for the midlatitude legs of three orbits in the late spring of 1974 are presented and compared with densities predicted by the AE-C (OSS) empirical N model at 375 km. Atomic nitrogen appeared to be in diffusive equilibrium at least above 200 km in each of the orbits studied. A typical number density of N at 200 km, 0900 LST, and 40 deg N latitude in late May 1974 is 30 million per cu cm.

Engebretson, M. J.↗
NASA NTRS1978

Wake characteristics of a tower for the DOE-NASA MOD-1 wind turbine

A 1/40th scale model of a tower concept designed for a MOD-1 wind power turbine was tested in a low speed wind tunnel. Wake wind speed profiles were measured, and from these were determined local values of wake minimum velocity ratio, average velocity ratio, and width over a range of tower elevations and wind approach angles. Comparison with results from two other all tubular models (MOD-0 and eight leg designs) tested earlier in the same tunnel indicated that wake width and flow blockage at the rotor plane of rotation were slightly larger for the MOD-1 tower than for the other two models. The differences in wake characteristics were attributed to differences in tower geometry and member dimensions.

Savino, J. M.↗
NASA NTRS1978

Flight demonstrations of curved, descending approaches and automatic landings using time referenced scanning beam guidance

The Terminal Configured Vehicle (TCV) program operates a Boeing 737 modified to include a second cockpit and a large amount of experimental navigation, guidance and control equipment for research on advanced avionics systems. Demonstration flights to include curved approaches and automatic landings were tracked by a phototheodolite system. For 50 approaches during the demonstration flights, the following results were obtained: the navigation system, using TRSB guidance, delivered the aircraft onto the 3 nautical mile final approach leg with an average overshoot of 25 feet past centerline, subjet to a 2-sigma dispersion of 90 feet. Lateral tracking data showed a mean error of 4.6 feet left of centerline at the category 1 decision height (200 feet) and 2.7 feet left of centerline at the category 2 decision height (100 feet). These values were subject to a sigma dispersion of about 10 feet. Finally, the glidepath tracking errors were 2.5 feet and 3.0 feet high at the category 1 and 2 decision heights, respectively, with a 2 sigma value of 6 feet.

White, W. F.↗
NASA NTRS1978

Alignment displacements of the solar optical telescope primary mirror

Solar optical telescope is a space shuttle payload which is at the present time (1978) being planned. The selected alignment method for the telescope's primary mirror is such that the six inclined legs supporting the mirror are at the same time motorized alignment actuators, changing their own length according to the alignment requirement and command. The alignment displacements were described, including circumvention of some apparent NASTRAN limitations.

Medenica, W. V.↗
NASA NTRS1977

Insulin and glucose responses during bed rest with isotonic and isometric exercise

The effects of daily intensive isotonic (68% maximum oxygen uptake) and isometric (21% maximum extension force) leg exercise on plasma insulin and glucose responses to an oral glucose tolerance test (OGTT) during 14-day bed-rest (BR) periods were investigated in seven young healthy men. The OGTT was given during ambulatory control and on day 10 of the no-exercise, isotonic, and isometric exercise BR periods during the 15-wk study. The subjects were placed on a controlled diet starting 10 days before each BR period. During BR, basal plasma glucose concentration remained unchanged with no exercise, but increased (P less 0.05) to 87-89 mg/100 ml with both exercise regimens on day 2, and then fell slightly below control levels on day 13. The fall in glucose content during BR was independent of the exercise regimen and was an adjustment for the loss of plasma volume. The intensity of the responses of insulin and glucose to the OGTT was inversely proportional to the total daily energy expenditure during BR. It was estimated that at least 1020 kcal/day must be provided by supplemental exercise to restore the hyperinsulinemia to control levels.

Dolkas, C. B.↗
NASA NTRS1977

Some opportunities in teleoperated mining

Processes involved in remote control mining (fragmentation, material handling, ground and environmental control) are discussed with reference to longwall shear mining, the method which affords the greatest potential for the use of teleoperated systems. The breakup and haulage procedures are outlined, with attention to environmental control subsystems, i.e., noise and dust abatement. A description of a four-legged chock, attached to a section of a face conveyor and operated remotely, is presented.

Palowitch, E. R.↗
NASA NTRS1978

6 centimeter observations of solar bursts with 6-inch resolution

During May 1974 data were collected on nine 6-cm solar bursts originating in two active regions. One-dimensional fan-beam scans were obtained every 30 seconds in order to study burst structure and evolution. Maximum burst flux was in the 0.34-12.0 sfu range. At maximum intensity the estimated brightness temperatures were in the 10 to the 6th to 2 x 10 to the 7th K range. Angular sizes ranged from 7-23 arcsec. In most cases an expansion of the burst core after maximum intensity was observed along with a drift in the position of the burst core. Four bursts were associated important H-alpha flares, and in all cases burst maximum occurred before flare maximum. The bursts were circularly polarized in the extraordinary mode sense during maximum intensity. Since the polarization was the same over the extent of the burst source, it is suggested that if the burst is associated with loop sources, the emission is associated with one leg of the loop.

Alissandrakis, C. E.↗