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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Preliminary report on the CTS transient event counter performance through the 1976 spring eclipse season

The transient event counter (TEC), senses and counts transients having a voltage rise of greater than five volts in three separate wire harnesses: the attitude control harness, the solar array instrumentation harness and the solar array power harness. The operational characteristics of TEC are defined and the preliminary results obtained through the first 90 days of operation including the spring 1976 eclipse season are presented. The results show that the Communications Technology Satellite was charged to the point where discharges occurred. The discharge induced transients did not cause any anomalous events in spacecraft operation. The data indicate that discharges can occur at any time during the day without preference to any local time quadrant. The number of discharges occurring in the one second sample interval are greater than anticipated. The compilation and review of the data is continuing.

Stevens, N. J.↗
NASA NTRS1977

Snowpack ground truth Donner Pass site, Soda Springs, California

Ground truth data taken near Soda Springs, California, on January 18, 1977, in support of the NASA Airborne Instrumentation Research Program are presented. Ground truth data taken in support of this mission were as follows: (1) snow depths were taken every 400 feet; (2) snow densities were taken every 1,200 feet; (3) two snowpits were dug, and limited density, vertical layer classifications, and soil observations were taken; and (4) temperatures of the upper 6 inches of the snowpack were taken at one location.

Jones, E. B.↗
NASA NTRS1977

A classification of large amplitude oscillations of a spring-pendulum system

We present a detailed classification of large amplitude oscillations of a non-integrable autonomous system with two degrees of freedom: the spring pendulum system. The classification is made with the method of invariant curves. The results show the importance of three types of motion: periodic, quasi-periodic and semi-ergodic. The numerical results are given for nine different values of the energy constant.

Broucke, R.↗
NASA NTRS1977

Preliminary report on the CTS transient event counter performance through the 1976 spring eclipse season

The transient event counter is described, defining its operational characteristics, and presenting the preliminary results obtained through the first 90 days of operation including the Spring 1976 eclipse season. The results show that the CTS was charged to the point where discharges have occurred. The discharge induced transients have not caused any anomalous events in spacecraft operation. The data indicate that discharges can occur at any time during the day without preference to any local time quadrant. The number of discharges occurring in the 1 sec sample interval are greater than anticipated.

Stevens, N. J.↗
NASA NTRS1976

Atmospheric ozone measurements made from B-747 airliners - Spring 1975

Atmospheric ozone in the upper troposphere and lower stratosphere north of the equator has been registered aboard two commercial B-747 airliners during the Spring of 1975. This monitoring is part of a much broader and continuing project developed by NASA and known as the Global Atmospheric Sampling Program (GASP). Additional flight and meteorological conditions have also been automatically recorded on board concurrent with the ozone measurements. Independently-derived tropopause pressure information was available from NMC data archives and was used to identify stratospheric and tropospheric flight. The composite ozone, flight and meteorological data are reported for selected dates in March, April, and May. Attention is drawn particularly to the vertical profiles of atmospheric ozone mixing ratio as a function of both distance from the tropopause and curvature of the streamlines. The GASP observations suggest that ozone levels typical of the lower stratosphere are often embedded in the upper troposphere, principally during occasions when cyclonic wind curvature was noted.

Falconer, P. D.↗
NASA NTRS1978

Environmental assessment of the proposed nonelectric application of geothermal resources at Desert Hot Springs, California

The paper presents an environmental analysis performed in evaluating various proposed geothermal demonstration projects at Desert Hot Springs. These are categorized in two ways: (1) indirect, or (2) direct uses. Among the former are greenhouses, industrial complexes, and car washes. The latter include aquaculture, a cascaded agribusiness system, and a mobile home park. Major categories of environmental impact covered are: (1) site, (2) construction of projects, and (3) the use of the geothermal source. Attention is also given to the disposal of the geothermal fluid after use. Finally, it is concluded that there are no major problems forseen for each project, and future objectives are discussed.

Rosenberg, L.↗
NASA NTRS1981

Interchangeable spring modules for inertia measurements

Operation of inertia balance is simplified by packaging set of balance springs in interchangeable modules. They are held in place in balance pedestal by just two fasteners, making removal and replacement fast and simple. With them, balance can be readied in less than 15 minutes, in contrast to more than 2 hours by previous method.

Mcnamara, J. W.↗
NASA NTRS1979

Mars south polar spring and summer temperatures - A residual CO2 frost

Viking infrared thermal mapper (IRTM) energy measurements over the Mars south polar cap throughout the Martian spring and summer revealed complex spatial, spectral, and temporal variations. High albedos did not directly correspond with low temperatures, and as the cap shrank to its residual position, it maintained large differences in brightness temperature between the four IRTM surface-sensing bands at 7, 9, 11, and 20 microns. The late summer infrared spectral pattern can be matched by a surface consisting of CO2 frost with 20 micron emissivity of 0.8 and about 6% dark, warm soil under a dusty atmosphere of moderate infrared opacity and spectral properties similar to those measured for the Martian global dust storms. Low temperature, the absence of appreciable water vapor in the south polar atmosphere, and the absence of surface warming expected if H2O were to become exposed, all imply that the residual south polar cap was covered by solid CO2.

Kieffer, H. H.↗
NASA NTRS1982

Spring Support for Turbopump Rotor Bearing

Novel bearing support for liquid-oxygen turbopumps protects against impact loads while avoiding a major disadvantage of earlier flexible supports. It allows controlled axial movement necessary for proper operation of pressure-operated pump impeller. While spring-loading rotor to midpoint of the axial movement to avoid impact-load damage to turbopump components. Support is made by machining azimuthal slots in cylindrical portion. Resulting structure permits controlled axial deformations.

Strangeland, M. L.↗
NASA NTRS1980

Normal crop calendars. Volume 2: The spring wheat states of Minnesota, Montana, North Dakota, and South Dakota

The state crop calendars for the principal spring wheat producing states within the United States are presented. These crop calendars are an update of those produced for the large area crop inventory experiment multilabeling task during 1978and are compiled for the foreign commodity production forecasting (FCPF) project of the agriculture and resources inventory surveys through aerospace remote sensing program.

West, W. L., III↗
NASA NTRS1981

Application of the line-spring model to a cylindrical shell containing a circumferential or axial part-through crack

An approximate solution was obtained for a cylindrical shell containing a part-through surface crack. It was assumed that the shell contains a circumferential or axial semi-elliptic internal or external surface crack and was subjected to a uniform membrane loading or a uniform bending moment away from the crack region. A Reissner type theory was used to account for the effects of the transverse shear deformations. The stress intensity factor at the deepest penetration point of the crack was tabulated for bending and membrane loading by varying three dimensionless length parameters of the problem formed from the shell radius, the shell thickness, the crack length, and the crack depth. The upper bounds of the stress intensity factors are provided by the results of the elasticity solution obtained from the axisymmetric crack problem for the circumferential crack, and that found from the plane strain problem for a circular ring having a radial crack for the axial crack. The line-spring model gives the expected results in comparison with the elasticity solutions. Results also compare well with the existing finite element solution of the pressurized cylinder containing an internal semi-elliptic surface crack.

Delale, F.↗
NASA NTRS1981

The Correo and Suwanee Spring meteorites - Two new ordinary chondrite finds

Two new ordinary chondrites were found about 40 km west of Albuquerque, New Mexico. Correo is an H4 chondrite with distinct chondrules and major olivine (Fo 81.4), orthopyroxene (En 82.3) and plagioclase (An 12). Suwanee Spring is an L5 chondrite with few distinct chondrules and a highly recrystallized matrix. Major minerals are olivine (Fo 75.4), orthopyroxene (En 77.7) and plagioclase (An 9). The metallic Ni-Fe phases of both meteorites are typical of slowly cooled ordinary chondrites.

Rubin, A. E.↗
NASA NTRS1981

Line-spring model for surface cracks in a Reissner plate

In this paper the line-spring model developed by Rice and Levy for a surface crack in elastic plates is reconsidered. The problem is formulated by using Reissner's plate bending theory. For the plane strain problem of a strip containing an edge crack and subjected to tension and bending new expressions for stress intensity factors are used which are valid up to a depth-to-thickness ratio of 0.8. The stress intensity factors for a semi-elliptic and a rectangular crack are calculated. Considering the simplicity of the technique and the severity of the underlying assumptions, the results compare rather well with the existing finite element solutions.

Delale, F.↗
NASA NTRS1981

Preliminary technical results review of FY81 experiments. Volume 1: Fiscal year 1981/82 spring small grains pilot experiment

Technical progress made in the foreign commodity production forecasting for the advancement of spring small grains (SSG) area estimation is reported with emphasis on results achieved since the last AgRISTARS level semiannual review. Major objectives and accomplishments are reviewed and the experiment is described. The technical approach data assessment, and data systems used are considered. Results of the group approach comparison study are presented along with preliminary aggregation results for SSG processing procedures. The outlook for the future is assessed.

Source record↗
NASA NTRS1984

Tool Releases Optical Elements From Spring Brackets

Threaded hooks retract bracket arms holding element. Tool uses three hooks with threaded shanks mounted in ring-shaped holder to pull on tabs to release optical element. One person can easily insert or remove optical element (such as prism or lens) from spring holder or bracket with minimal risk of damage.

Gum, J. S.↗
NASA NTRS1982

Evaluation of the Williams-type spring wheat model in North Dakota and Minnesota

The Williams type model, developed similarly to previous models of C.V.D. Williams, uses monthly temperature and precipitation data as well as soil and topological variables to predict the yield of the spring wheat crop. The models are statistically developed using the regression technique. Eight model characteristics are examined in the evaluation of the model. Evaluation is at the crop reporting district level, the state level and for the entire region. A ten year bootstrap test was the basis of the statistical evaluation. The accuracy and current indication of modeled yield reliability could show improvement. There is great variability in the bias measured over the districts, but there is a slight overall positive bias. The model estimates for the east central crop reporting district in Minnesota are not accurate. The estimate of yield for 1974 were inaccurate for all of the models.

Leduc, S.↗