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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Calculation of the twist distribution of wings designed for cruise at transonic speeds

The use of linear theory in calculating the twist distribution of a wing designed for cruise at supercritical speeds is justified on the basis of the transonic equivalence rule. A modified version of Multhopp's subsonic lifting-surface theory was used to calculate the twist distribution. The lifting-surface theory is compared with both slender wing theory and experimental results. A study was also made of the effect of wing sweep on the twist distribution required to maintain an elliptic span load at cruise conditions. The important parameters used in establishing this twist distribution are identified.

Mann, M. J.↗
NASA NTRS1974

Dissipation of energy in model experiments

Interaction studies of a plasma stream with a magnetic dipole have shown that the thickness of the plasma/field interlayer is considerably greater than the characteristic plasma dimension c/omega sub 0. Broadening of the layer is due to the formation of a collisionless shock wave. To demonstrate collisionless dissipation, the Joulean losses were calculated using the conductivity value obtained from the skin layer thickness. Analysis of the various physical processes showed that the hypothesis of collisionless dissipation of the directional plasma flow is justified.

Podgornyy, I. M.↗
NASA NTRS1974

Methodological questions of creating tissue-equivalent phantoms

On the basis of analysis and generalization of literature data, the composition of tissue equivalent plastic was justified, parameters of a standard man were determined, plaster and metal forms were created for casting dummies, and an experimental model was produced from tissue equivalent material.

Kolodkin, A. V.↗
NASA NTRS1975

Space data relay systems

Significant progress has been achieved in simplifying platform concepts through random access techniques. This is particularly important in applications such as balloons where weight is critical. In applications, where weight restriction may not be a problem, the concept lends itself to uncomplicated designs and low cost. Nevertheless, ordered systems offer inherent advantages in managing data flow which justifies their use. With continuing improvements in technology, particularly low power receivers, ordered systems should become quite competitive with random systems for many applications.

Cote, C. E.↗
NASA NTRS1974

Space processing economics

Two types of space processing operations may be considered economically justified; they are manufacturing operations that make profits and experiment operations that provide needed applied research results at lower costs than those of alternative methods. Some examples from the Skylab experiments suggest that applied research should become cost effective soon after the space shuttle and Spacelab become operational. In space manufacturing, the total cost of space operations required to process materials must be repaid by the value added to the materials by the processing. Accurate estimates of profitability are not yet possible because shuttle operational costs are not firmly established and the markets for future products are difficult to estimate. However, approximate calculations show that semiconductor products and biological preparations may be processed on a scale consistent with market requirements and at costs that are at least compatible with profitability using the Shuttle/Spacelab system.

Bredt, J. H.↗
NASA NTRS1974

Study of ceramic products and processing techniques in space

An analysis of the solidification kinetics of beta alumina in a zero-gravity environment was carried out, using computer-simulation techniques, in order to assess the feasibility of producing high-quality single crystals of this material in space. The two coupled transport processes included were movement of the solid-liquid interface and diffusion of sodium atoms in the melt. Results of the simulation indicate that appreciable crystal-growth rates can be attained in space. Considerations were also made of the advantages offered by high-quality single crystals of beta alumina for use as a solid electrolyte; these clearly indicate that space-grown materials are superior in many respects to analogous terrestrially-grown crystals. Likewise, economic considerations, based on the rapidly expanding technological applications for beta alumina and related fast ionic conductors, reveal that the many superior qualities of space-grown material justify the added expense and experimental detail associated with space processing.

Markworth, A. J.↗
NASA NTRS1974

A city invests in its future

Events occurring during the past four years which led to the City of Burbank's decision to acquire an energy source adequate for the city's present and future power requirements are discussed. The community reaction to this unprecedented move is also covered. Burbank's long-range plans for the development of geothermal energy are outlined as well as the challenges which confront a public utility in implementing its projected goals. There are several advantages accurring to the city which in the opinion of the Burbank City Council and the administration justify this venture. The need for a cooperative climate which will enable all electrical utilities to better meet their obligations to the public, which is their prime responsibility before all other considerations, is analyzed.

Baker, J. N.↗
NASA NTRS1974

Evaluation of the application of ERTS-1 data to the regional land use planning process

The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis.

Clapp, J. L.↗
NASA NTRS1975

Maximum likelihood signature estimation

Maximum-likelihood estimates are discussed which are based on an unlabeled sample of observations, of unknown parameters in a mixture of normal distributions. Several successive approximation procedures for obtaining such maximum-likelihood estimates are described. These procedures, which are theoretically justified by the local contractibility of certain maps, are designed to take advantage of good initial estimates of the unknown parameters. They can be applied to the signature extension problem, in which good initial estimates of the unknown parameters are obtained from segments which are geographically near the segments from which the unlabeled samples are taken. Additional problems to which these methods are applicable include: estimation of proportions and adaptive classification (estimation of mean signatures and covariances).

Walker, H. F.↗
NASA NTRS1975

A study of total space life performance of GSFC spacecraft

The space life performance of 57 Goddard Space Flight Center spacecraft is given. The time distribution of 449 malfunctions, of which 248 were classified as failures, is presented. Test data were available for 39 of the spacecraft and permitted a comparison of system test performance with the first-day, first-month, and total space life performance. The failures per spacecraft for the system environmental tests and the three time periods in space were 12, 0.9, 1.7, and 5.0, respectively. Relevance of the data to the pre-shuttle and shuttle eras is discussed. Classifications of failures by type of device and spacecraft subsystem are included. A continuation of the Goddard philosophy of requiring a system-level environmental test program is justified.

Timmins, A. R.↗
NASA NTRS1974

Determination of failure limits for sterilizable solid rocket motor

A structural evaluation to establish probable failure limits and a series of environmental tests involving temperature cycling, sustained acceleration, and vibration were conducted on an 18-inch diameter solid rocket motor. Despite the fact that thermal, acceleration and vibration loads representing a severe overtest of conventional environmental requirements were imposed on the sterilizable motor, no structural failure of the grain or flexible support system was detected. The following significant conclusions are considered justified. It is concluded that: (1) the flexible grain retention system, which permitted heat sterilization at 275 F on the test motor, can readily be adopted to meet the environmental requirements of an operational motor design, and (2) if further substantiation of structural integrity is desired, the motor used is considered acceptable for static firing.

Lambert, W. L.↗
NASA NTRS1975

Investigation of relationships between linears, total and hazy areas, and petroleum production in the Williston Basin: An ERTS approach

The author has identified the following significant results. ERTS-1 imagery in a variety of formats was used to locate linear, tonal, and hazy features and to relate them to areas of hydrocarbon production in the Williston Basin of North Dakota, eastern Montana, and northern South Dakota. Derivative maps of rectilinear, curvilinear, tonal, and hazy features were made using standard laboratory techniques. Mapping of rectilinears on both bands 5 and 7 over the entire region indicated the presence of a northeast-southwest and a northwest-southeast regional trend which is indicative of the bedrock fracture pattern in the basin. Curved lines generally bound areas of unique tone, maps of tonal patterns repeat many of the boundaries seen on curvilinear maps. Tones were best analyzed on spring and fall imagery in the Williston Basin. It is postulated that hazy areas are caused by atmospheric phenomena. The ability to use ERTS imagery as an exploration tool was examined where petroleum and gas are presently produced (Bottineau Field, Nesson and Antelope anticlines, Redwing Creek, and Cedar Creek anticline). It is determined that some tonal and linear features coincide with location of present production in Redwing and Cedar Creeks. In the remaining cases, targets could not be sufficiently well defined to justify this method.

Erickson, J. M.↗
NASA NTRS1975

Costs and benefits of turbine blades

The potential demand for space processed turbine blades, and the dollar benefits to be derived from this technology were analyzed. It was found that an adequate demand to justify space processed blades will exist. The cost benefits per blade for replacements in existing aircraft is estimated to be $997.50 per blade, and for new aircraft the savings per blade would be over $21,000.00.

Source record↗
NASA NTRS1975

Digital control of high-intensity acoustic testing

To eliminate previous system instabilities and control high-intensity acoustic tests, a digital control vibration test system is modified by a software change. Three systems for the control of acoustic testing are compared: a hybrid digital/analog system, a digital vibration system, and the same digital vibration system modified by a software change to allow acoustic testing. It is shown that the hybrid system and the modified vibration system exhibit almost equal performance, although the hybrid system performs testing twice as fast. The development of a specialized acoustic test control system is justified since it costs far less than the general-purpose vibration control system. However, the latter is much easier to set up for a test, which is important in preventing overtesting of valuable spacecraft components.

Slusser, R. A.↗
NASA NTRS1975

Space processing of crystals for opto-electronic devices: The case for solution growth

The results obtained during a six month program aimed at determining the viability of space processing in the 1980's of dielectric-elastic-magnetic single crystals were described. The results of this program included: identification of some important emerging technologies dependent on dielectric-elastic-magnetic crystals, identification of the impact of intrinsic properties and defects in the single crystals on system performance, determination of a sensible common basis for the many crystals of this class, and identification of the benefits of micro-gravity and some initial experimental evidence that these benefits can be realized in space. It is concluded that advanced computers and optical communications are at a development stage for high demand of dielectric-elastic-magnetic single crystals in the mid-1980's. Their high unit cost and promise for significantly increased perfection by growth in space justified pursuit of space processing.

Hayden, S. C.↗
NASA NTRS1975

Conservation: Toward firmer ground

The following aspects of energy conservation were reviewed in order to place the problems in proper perspective: history and goals, conservation accounting-criteria, and a method to overcome obstacles. The effect of changing prices and available supplies of energy sources and their causes on consumption levels during the last few decades were described. Some examples of attainable conservation goals were listed and justified. A number of specific criteria applicable to conservation accounting were given. Finally, a discussion was presented to relate together the following aspects of energy conservation: widespread impact, involvement of government, industry, politics, moral and ethical aspects, urgency and time element.

Source record↗
NASA NTRS1975

Application of LANDSAT to the Surveillance and Control of Lake Eutrophication in the Great Lakes Basin

The author has identified the following significant results. Computer techniques developed for mapping water quality parameters from LANDSAT data were demonstrated, using ground truth collected in an ongoing survey of water quality in Saginaw Bay (Lake Huron), Michigan. Regression correlation coefficients varied from 0.99 for total phosphorus to 0.72 for chlorophyll-a corrected. Five water quality parameters are best correlated with LANDSAT band 6 alone. Temperature relates to band 5 alone and only two bands are justified for mapping the remaining six parameters. LANDSAT CCTs were used as a basis for inventorying land use within each of the Ohio-Kentucky-Indiana regional commissions, 225 drainage areas, and nine counties. Sixteen categories were merged into ten categories and mapped at a scale of 1 in. = 5,000 ft, with detail to 0.44 hectares for the 2,700 sq mi region. These products were produced in less than 90 days at a cost of one cent an acre. LANDSAT CCTS were also used as a basis for inventorying land cover within the Triangle J council of governments 1,750 sq mi study area. The complete inventory was accomplished within a period of 60 days at a cost of about one half cent per acre.

Rogers, R. H.↗
NASA NTRS1975

Electromagnetic wave energy conversion research

Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.

Bailey, R. L.↗