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  • Chemistry  (49,949)
  • ENERGY PRODUCTION AND CONVERSION  (2,381)
  • Cell & Developmental Biology  (2,140)
  • STRUCTURAL MECHANICS  (1,550)
  • Deutschland
  • 1975-1979  (34,330)
  • 1960-1964  (21,694)
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Keywords
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Year
  • 1
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    Malaria in Deutschland (1979)
    In:  Bundesgesundheitsblatt 22, 8-13
    Details
    Publication Date: 1979
    Description: einheimische Malaria als man-made-disease KATASTER-BESCHREIBUNG: KATASTER-DETAIL:
    Keywords: Deutschland ; Umweltmedizin ; Infektionskrankheiten
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    BIBLIOGRAPHY INKA BB
  • 2
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    Benzo(a)pyrene-7,8-dihydrodiol 9,10-oxide adenosine and deoxyadenosine adducts: structure and stereochemistry (1979)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1979-12-14
    Description: The structure and absolute stereoconfigurations of four adenosine adducts with (+/-)-7 alpha,8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) and their deoxyadenosine analogs have been determined. They result from both cis and trans addition of the N6 amino group of ademine to the 10 position of both enantiomers of BDPE. This was determined from studies of the nuclear magnetic resonance spectra, mass spectra, and circular dichroism spectra, as well as from their pKa values and chemical reactivities.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jeffrey, A M -- Grzeskowiak, K -- Weinstein, I B -- Nakanishi, K -- Roller, P -- Harvey, R G -- New York, N.Y. -- Science. 1979 Dec 14;206(4424):1309-11.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/316186" target="_blank"〉PubMed〈/a〉
    Keywords: *Benzopyrenes ; Chemical Phenomena ; Chemistry ; Circular Dichroism ; Dna ; *Deoxyadenosines/analogs & derivatives ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Molecular Conformation ; Mutation ; Stereoisomerism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    N-formyliminodiacetic acid, a new compound from the reaction of nitrilotriacetic acid and chlorine (1979)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1979-06-08
    Description: It has been proposed that nitrilotriacetic acid be substituted for trisodium polyphosphates in detergents as a way to reduce the rate of eutrophication in the Great Lake Basin. The reaction of nitrilotriacetic acid with chlorine-containing solutions produces a hitherto unknown degradation production, N-formyliminodiacetic acid, in high yield. The toxicological and environmental implications of this reaction are unclear.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Spanggord, R J -- Tyson, C A -- New York, N.Y. -- Science. 1979 Jun 8;204(4397):1081-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/36659" target="_blank"〉PubMed〈/a〉
    Keywords: *Acetates ; Chemical Phenomena ; Chemistry ; *Chlorine ; Dicarboxylic Acids ; Environmental Pollutants ; Hydrogen-Ion Concentration ; *Imino Acids ; Mutagens ; *Nitrilotriacetic Acid
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 4
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    HCN did not condense to give heteropolypeptides on the primitive earth (1979)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1979-03-16
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ferris, J P -- New York, N.Y. -- Science. 1979 Mar 16;203(4385):1135-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/218287" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; *Hydrogen Cyanide ; *Peptides
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 5
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    Combined vibration/temperature/sideload environmental testing of UHF blade antennas (1979)
    In:  CASI
    Details
    Publication Date: 2006-07-02
    Description: Service problems encountered on the F-4 aircraft showed that the environmental qualification requirements for the UHF blade antenna were not adequate. Although the individual environmental levels were stringent enough, only combined environmental testing could duplicate the conditions in which service problems occurred. Techniques for applying static side load simultaneously with vibration and temperature were developed. The combined environment testing was instrumental in the rapid assessment of antenna modifications and resulted in a final configuration which proved satisfactory in service. A need to include combined environmental testing for qualification of blade antennas was established.
    Keywords: STRUCTURAL MECHANICS
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., Pt. 3; p 79-84
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  • 6
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    DSN energy data base preliminary design (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The design and implementation of a computerized data base created to support the DSN Energy Conservation Project with data relating to energy use at Goldstone Deep Space Communications Complex are described. The results of development work to date, are presented along with work currently in progress or in the planning stage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Deep Space Network; p 167-181
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  • 7
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    A simplified method of evaluating the stress wave environment of internal equipment (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A simplified method called the transfer function technique (TFT) was devised for evaluating the stress wave environment in a structure containing internal equipment. The TFT consists of following the initial in-plane stress wave that propagates through a structure subjected to a dynamic load and characterizing how the wave is altered as it is transmitted through intersections of structural members. As a basis for evaluating the TFT, impact experiments and detailed stress wave analyses were performed for structures with two or three, or more members. Transfer functions that relate the wave transmitted through an intersection to the incident wave were deduced from the predicted wave response. By sequentially applying these transfer functions to a structure with several intersections, it was found that the environment produced by the initial stress wave propagating through the structure can be approximated well. The TFT can be used as a design tool or as an analytical tool to determine whether a more detailed wave analysis is warranted.
    Keywords: STRUCTURAL MECHANICS
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., Pt. 1; p 89-96
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  • 8
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    High G pyrotechnic shock simulation using metal-to-metal impact (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A technique for simulating high g level pyrotechnic shocks is described and the results of applying the technique to obtain the MIL-STD-1540A shock spectrum with a maximum acceleration of 18,000g at 2,000 Hz are presented. Designing the resonant beam and plate on which the test unit is mounted, and generating a proper impulsive load on them, were the essentials of the technique. One dimensional stress wave and Euler equations were employed in the design. A metal pendulum hammer was used to generate the impulsive load.
    Keywords: STRUCTURAL MECHANICS
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., Pt. 1; p 97-100
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  • 9
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    Probability of failure prediction for step-stress fatigue under sine or random stress (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A previously proposed cumulative fatigue damage law is extended to predict the probability of failure or fatigue life for structural materials with S-N fatigue curves represented as a scatterband of failure points. The proposed law applies to structures subjected to sinusoidal or random stresses and includes the effect of initial crack (i.e., flaw) sizes. The corrected cycle ratio damage function is shown to have physical significance.
    Keywords: STRUCTURAL MECHANICS
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., Pt. 1; p 31-41
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  • 10
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    Potential prediction needs in support of energy systems (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The relationship between emerging energy systems and the natural environment is discussed, including selected examples to show that energy systems are tied to global solar terrestrial processess. The interdependence of resources, technology, and environmental impact is considered in terms of needed geophysical, atmospheric, and solar terrestrial data inputs. The need for long term basic research on the solar terrestrial system is emphasized.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 198-202
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  • 11
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    Mechanics of fracture - Fundamentals and some recent developments (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: An overview is presented of the fundamental aspects of and recent developments in fracture mechanics. Reference is made to linear elastic fracture mechanics including the state of stresses and displacements in the vicinity of cracks, effects of crack geometry and orientation on stress intensity factors, energy balance of Griffith, Irwin's stress intensity concept, and linear elastic fracture mechanics testing for fracture toughness. Other aspects of this paper include the non-linear behavior of materials and their influence on fracture mechanics parameters, consideration of viscoelasticity and plasticity, non-linear fracture toughness parameters as C.O.D., R-curve and J-integral, and a non-linear energy method, proposed by Liebowitz. Finite element methods applied to fracture mechanics problems are indicated. Also, consideration has been given to slow crack growth, dynamic effects on K(IC), Sih's criterion for fracture, Lee and Liebowitz's criterion relating crack growth with plastic energy, and applications of fracture mechanics to aircraft design. Suggestions are offered for future research efforts to be undertaken in fracture mechanics.
    Keywords: STRUCTURAL MECHANICS
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    NASA TECHNICAL REPORTS
  • 12
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    NASA-Langley Research Center's participation in a round-robin comparison between some current crack-propagation prediction methods (1979)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A round-robin study was conducted which evaluated and compared different methods currently in practice for predicting crack growth in surface-cracked specimens. This report describes the prediction methods used by the Fracture Mechanics Engineering Section, at NASA-Langley Research Center, and presents a comparison between predicted crack growth and crack growth observed in laboratory experiments. For tests at higher stress levels, the correlation between predicted and experimentally determined crack growth was generally quite good. For tests at lower stress levels, the predicted number of cycles to reach a given crack length was consistently higher than the experimentally determined number of cycles. This consistent overestimation of the number of cycles could have resulted from a lack of definition of crack-growth data at low values of the stress intensity range. Generally, the predicted critical flaw sizes were smaller than the experimentally determined critical flaw sizes. This underestimation probably resulted from using plane-strain fracture toughness values to predict failure rather than the more appropriate values based on maximum load.
    Keywords: STRUCTURAL MECHANICS
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  • 13
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    A review and assessment of the stress-intensity factors for surface cracks (1979)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The stress-intensity factor solutions proposed for a surface crack in a finite plate subjected to uniform tension are reviewed. Fourteen different solutions obtained over the past 16 years using approximate analytical methods, experimental methods, and engineering estimates are compared. The accuracy of the various solutions is assessed by correlating fracture data on surface-cracked tension specimens made of a brittle epoxy material. Fracture of the epoxy material was characterized by a constant value of stress-intensity factor as failure. Thus, the correctness of various solutions is judged by the variations in the stress-intensity factors at failure. The solutions were ranked in order of minimum standard deviation. The highest ranking solutions correlated 95% of data analyzed within + or - 10% whereas the lowest ranking solutions correlated 95% of data analyzed within + or - 20%. Some solutions could be applied to all data considered, whereas others were limited with respect to crack shapes and crack sizes that could be analyzed.
    Keywords: STRUCTURAL MECHANICS
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  • 14
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    A device model for the tandem junction solar cell (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A conceptual device model has been developed to explain operation of the tandem junction cell (TJC) when back contacts only are used. Operation and parameters of the cell are explained by transistor action. Experimental observations are presented which confirm that current is collected for carrier generation in the front uncontacted n(plus) region. The model should be useful as a guideline to optimize the TJC by application of transistor design principles.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-26; Sept
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  • 15
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    The importance of surface recombination and energy-bandgap narrowing in p-n-junction silicon solar cells (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Experimental data demonstrating the sensitivity of open-circuit voltage to front-surface conditions are presented for a variety of p-n-junction silicon solar cells. Analytical models accounting for the data are defined and supported by additional experiments. The models and the data imply that a) surface recombination significantly limits the open-circuit voltage (and the short-circuit current) of typical silicon cells, and b) energy-bandgap narrowing is important in the manifestation of these limitations. The models suggest modifications in both the structural design and the fabrication processing of the cells that would result in substantial improvements in cell performance. The benefits of one such modification - the addition of a thin thermal silicon-dioxide layer on the front surface - are indicated experimentally.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-26; Sept
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  • 16
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    Evaluation of models to predict insolation on tilted surfaces (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An empirical study was performed to evaluate the validity of various insolation models which employ either an isotropic or an anisotropic distribution approximation for sky light when predicting insolation on tilted surfaces. Data sets of measured hourly insolation values were obtained over a 6-month period using pyranometers which received diffuse and total solar radiation on a horizontal plane and total radiation on surfaces tilted toward the equator at 37 degrees and 60 degrees angles above the horizon. Data on the horizontal surfaces were used in the insolation models to predict insolation on the tilted surface; comparisons of measured vs calculated insolation on the tilted surface were examined to test the validity of the sky light approximations. It was found that the Liu-Jordan isotropic distribution model provides a good fit to empirical data under overcast skies but underestimates the amount of solar radiation incident on tilted surfaces under clear and partly cloudy conditions.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 23; 2, 19; 1979
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  • 17
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    Finite dynamic element formulation for a plane triangular element (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Higher order correction terms for the stiffness and inertia matrices associated with a triangular plane stress-strain finite dynamic element are developed in detail. Numerical results are presented which indicate that the adoption of these matrices along with a suitable quadratic matrix eigenproblem solver effects a significant economy in the free vibration solution of structure when compared with the analysis based on the usual finite element procedure. Finally, a FORTRAN IV computer program listing of the various relevant matrices is given.
    Keywords: STRUCTURAL MECHANICS
    Type: International Journal for Numerical Methods in Engineering; 14; 10, 1; 1979
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  • 18
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    A simple theory of back-surface-field /BSF/ solar cells (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An earlier calculation of the I-V characteristics of solar cells contains a mistake. The current generated by light within the depletion layer is too large by a factor of 2. When this mistake is corrected, not only are all previous conclusions unchanged, but the agreement with experiment becomes better. Results are presented in graphical form of new computations which not only take account of the factor of 2, but also include more recent data on material parameters.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Applied Physics; 50; Aug. 197
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  • 19
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    Low-cost encapsulation materials for terrestrial solar cell modules (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper presents the findings of material surveys intended to identify low cost materials which could be functional as encapsulants (by 1986) for terrestrial solar cell modules. Economic analyses have indicated that in order to meet the low cost goal of $2.70 per sq m, some or all of the following material technologies must be developed or advanced: (1) UV screening outer covers; (2) elastomeric acrylics; (3) weatherproofing and waterproofing of structural wood and paper products; (4) transparent UV stabilizers for the UV-sensitive transparent pottants; and (5) cost-effective utilization of silicone and fluorocarbon materials.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 22; 4, 19; 1979
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  • 20
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    Analysis of beam-like lattice trusses (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A simple procedure is presented for predicting the thermoelastic and free vibration responses of large repetitive beam-like trusses. The procedure is based on replacing the original lattice structure by an equivalent continuum beam model and obtaining closed-form (exact) solutions for the beam model. The equivalent beam model accounts for warping and shear deformation in the plane of the cross-section and is characterized by its thermoelastic strain and kinetic energies, from which the equations of motion and constitutive relations can be derived. The high accuracy of the results obtained by the proposed approach is demonstrated by means of numerical examples.
    Keywords: STRUCTURAL MECHANICS
    Type: Computer Methods in Applied Mechanics and Engineering; 20; Oct. 197
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  • 21
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    Solar cell spectral response characterization (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The absolute spectral response of solar cells is reported in the 400-1000-nm spectral region. Measurements were performed using two different types of monochromatic sources: amplitude-stabilized CW laser lines and interference filters with an incandescent lamp. Both types of calibration procedures use electrical substitution radiometry as the basis of traceability to absolute SI units. The accuracy of the calibration is shown to be limited by the nonideal characteristics of the solar cells themselves, specifically spatial nonuniformities and nonlinearities induced by high light levels.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Applied Optics; 18; Dec. 1
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  • 22
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    Some observations regarding the statistical determination of stress rupture regression lines (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observations concerning the statistical evaluation of creep data are presented. Methods currently employed in the determination of stress rupture regression lines can result in conflicting and necessarily invalid results. Anomalous behavior is principally associated with the selection of the dependent variable. However, it is the least squares method of curve fitting which introduces regression bias. Methods to improve the validity of least squares regressions are suggested.
    Keywords: STRUCTURAL MECHANICS
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  • 23
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    Buckling of rotating beams (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The stability of a beam subjected to compressive centrifugal forces arising from steady rotation about an axis which does not pass through the clamped end of the beam is analyzed to determine the critical rotational speeds for buckling in the inplane and out-of-plane directions. The differential equations of motion are solved numerically using an integrating matrix method in combination with an eigenanalysis to determine the eigenvalues from which stability is assessed. The results clarify several differences which have been identified in the literature relating to the proper behavior of the critical rotational speed for buckling as the radius of rotation of the clamped end of the beam is reduced.
    Keywords: STRUCTURAL MECHANICS
    Type: International Journal of Mechanical Sciences; 21; 12, 1; 1979
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  • 24
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    Simple spline-function equations for fracture mechanics calculations (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper presents simple spline-function equations for fracture mechanics calculations. A spline function is a sequence of piecewise polynomials of degree n greater than 1 whose coefficients are such that the function and its first n-1 derivatives are continuous. Second-degree spline equations are presented for the compact, three point bend, and crack-line wedge-loaded specimens. Some expressions can be used directly, so that for a cyclic crack propagation test using a compact specimen, the equation given allows the cracklength to be calculated from the slope of the load-displacement curve. For an R-curve test, equations allow the crack length and stress intensity factor to be calculated from the displacement and the displacement ratio.
    Keywords: STRUCTURAL MECHANICS
    Type: International Journal of Fracture; 15; Oct. 197
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  • 25
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    A quarter-century of progress in the development of correlation and extrapolation methods for creep rupture data (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Developments in the analysis of creep-rupture data are reviewed with particular reference to time temperature relations for the correlation and extrapolation of creep and stress rupture data, the minimum commitment method, and successive regression methods. Some contributions to the development of time-temperature parameters are noted.
    Keywords: STRUCTURAL MECHANICS
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  • 26
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    Radiation energy conversion in space (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Topics discussed at the third NASA conference on radiant energy conversion are reviewed. The unconcentrated-photovoltaic-generation version of a solar power satellite is described, noting that it will consist of a 21.3 x 5.3-sq-km silicon-solar-cell array expected to provide 17 Gw of electrical power, with 1 km in diam transmitters oriented to beam 2.45 GHz microwave power to two receiving/rectifying 'rectennas' on earth. The Solares space-energy-system concept, designed for providing a large fraction of the world's energy needs at costs comparable to those of future coal/nuclear alternative, is considered, as are subsystems for improving the economics of the solar power satellite. A concept proposing the use of relativistic-electron-storage rings for electron-beam energy transmission and storage, and a report on the production of a high temperature plasma with concentrated solar radiation are taken into account. Laser-conversion systems, including the direct-solar-pumped space laser, and the telec-powered spacecraft, are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Astronautics and Aeronautics; 17; Mar. 197
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  • 27
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    Wave propagation in transversely impacted composite laminates (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An experimental study was conducted to determine the wave-propagation characteristics, transient strains and residual properties of unidirectional and angle-ply boron/epoxy and graphite/epoxy laminates impacted with silicon-rubber projectiles at velocities up to 250 m/sec. Results include the following: (1) the predominant wave is the flexural wave propagating at different velocities in different directions; (2) peak strains and strain rates in the transverse to the (outer) fiber direction are much higher than those in the direction of the fibers; (3) strain rates up to 640/sec were measured; and (4) unidirectional laminates under impact showed appreciable modulus and strength degradation in the direction transverse to fibers.
    Keywords: STRUCTURAL MECHANICS
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  • 28
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    Analysis of misalignment in the tension test (1979)
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    Publication Date: 2011-08-17
    Description: Many experimenters fail to appreciate the significance of test system alignment during a tensile test. Poor alignment can increase data scatter and significantly influence some of the test results. In this paper a comprehensive analytical study of the misalignment problem in the plastic strain range is presented and errors caused by misalignment estimated. The results show that the stress-strain curve is not significantly affected by misalignment. However, the strains at the outermost fibers of the specimen cross-section are strongly affected by misalignment. Therefore, the effect of misalignment is most important when properties sensitive to local strain concentrations are being investigated.
    Keywords: STRUCTURAL MECHANICS
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  • 29
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    Non-linear dynamic response of a wind turbine blade (1979)
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    Publication Date: 2011-08-17
    Description: The paper outlines the nonlinear dynamic analysis of an isolated three-degree flap-lag-feather wind turbine blade under a gravity field and with shear flow. Lagrangian equations are used to derive the nonlinear equations of motion of blade for arbitrarily large angular deflections. The limit cycle analysis for forced oscillations and the determination of the principal parametric resonance of the blade due to periodic forces from the gravity field and wind shear are performed using the harmonic balance method. Results are obtained first for a two-degree flap-lag blade, then the effect of the third degree of freedom (feather) is studied. The self-excited flutter solutions are obtained for a uniform wind and with gravity forces neglected. The effects of several parameters on the blade stability are examined, including coning angle, structural damping, Lock number, and feather frequency. The limit cycle flutter solution of a typical configuration shows a substantial nonlinear softening spring behavior.
    Keywords: STRUCTURAL MECHANICS
    Type: Journal of Sound and Vibration; 63; Mar. 22
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  • 30
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    Recent finite element studies in plasticity and fracture mechanics (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The paper reviews recent work on fundamentals of elastic-plastic finite-element analysis and its applications to the mechanics of crack opening and growth in ductile solids. The presentation begins with a precise formulation of incremental equilibrium equations and their finite-element forms in a manner valid for deformations of arbitrary magnitude. Special features of computational procedures are outlined for accuracy in view of the near-incompressibility of elastic-plastic response. Applications to crack mechanics include the analysis of large plastic deformations at a progressively opening crack tip, the determination of J integral values and of limitations to J characterizations of the intensity of the crack tip field, and the determination of crack tip fields in stable crack growth.
    Keywords: STRUCTURAL MECHANICS
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    Application of the superposition principle to solar-cell analysis (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The superposition principle of differential-equation theory - which applies if and only if the relevant boundary-value problems are linear - is used to derive the widely used shifting approximation that the current-voltage characteristic of an illuminated solar cell is the dark current-voltage characteristic shifted by the short-circuit photocurrent. Analytical methods are presented to treat cases where shifting is not strictly valid. Well-defined conditions necessary for superposition to apply are established. For high injection in the base region, the method of analysis accurately yields the dependence of the open-circuit voltage on the short-circuit current (or the illumination level).
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-26; Mar. 197
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  • 32
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    Stress-intensity factors for a wide range of semi-elliptical surface cracks in finite-thickness plates (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Surface cracks are among the more common flaws in aircraft and pressure vessel components. Several calculations of stress-intensity factors for semi-elliptical surface cracks subjected to tension have appeared in the literature. However, some of these solutions are in disagreement by 50-100%. In this paper, stress-intensity factors for shallow and deep semi-elliptical surface cracks in plates subjected to tension are presented. To verify the accuracy of the three-dimensional finite-element models employed, convergence was studied by varying the number of degrees of freedom in the models from 1500 to 6900. The 6900 degrees of freedom used here were more than twice the number used in previously reported solutions. Also, the stress-intensity variations in the boundary-layer region at the intersection of the crack with the free surface were investigated.
    Keywords: STRUCTURAL MECHANICS
    Type: Engineering Fracture Mechanics; 11; 4, 19; 1979
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  • 33
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    Comparison of two total energy systems for a diesel power generation plant (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The capabilities and limitations, as well as the associated costs for two total energy systems for a diesel power generation plant are compared. Both systems utilize waste heat from engine cooling water and waste heat from exhaust gases. Pressurized water heat recovery system is simple in nature and requires no engine modifications, but operates at lower temperature ranges. On the other hand, a two-phase ebullient system operates the engine at constant temperature, provides higher temperature water or steam to the load, but is more expensive.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Deep Space Network; p 89-93
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  • 34
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    A two-dimensional thermal analysis of a new high-performance tubular solar collector (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The first of two articles are presented which describe and analyze the thermal performance of a vacuum tube solar collector. The assumptions and mathematical modeling are presented. The problem is reduced to the formulation of two simultaneous linear differential equations characterizing the collector thermal behavior. After applying the boundary conditions, a general solution is obtained which is found similar to the general Hottel, Whillier and Bliss form but with a complex flow factor.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Deep Space Network; p 116-131
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  • 35
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    The updated algorithm of the Energy Consumption Program (ECP): A computer model simulating heating and cooling energy loads in buildings (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The energy Comsumption Computer Program was developed to simulate building heating and cooling loads and compute thermal and electric energy consumption and cost. This article reports on the new additional algorithms and modifications made in an effort to widen the areas of application. The program structure was rewritten accordingly to refine and advance the building model and to further reduce the processing time and cost. The program is noted for its very low cost and ease of use compared to other available codes. The accuracy of computations is not sacrificed however, since the results are expected to lie within + or - 10% of actual energy meter readings.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Deep Space Network; p 107-115
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  • 36
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    Photovoltaic system criteria documents. Volume 5: Safety criteria for photovoltaic applications (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Methodology is described for determining potential safety hazards involved in the construction and operation of photovoltaic power systems and provides guidelines for the implementation of safety considerations in the specification, design and operation of photovoltaic systems. Safety verification procedures for use in solar photovoltaic systems are established.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-183320 , JPL-5250-3-VOL-5 , NAS 1.26:183320
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    Photovoltaic system criteria documents. Volume 3: Environmental issues and evaluation criteria for photovoltaic applications (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The environmental issues and evaluation criteria relating to the suitability of sites proposed for photovoltaic (PV) system deployment are identified. The important issues are defined, briefly discussed and then developed into evaluation criteria. System designers are provided with information on the environmental sensitivity of PV systems in realistic applications, background material which indicates the applicability of the siting issues identified, and evaluation criteria are defined to facilitate the selection of sites that maximize PV system operation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-183318 , JPL-5250-3-VOL-3 , NAS 1.26:183318
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  • 38
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    Photovoltaic system criteria documents. Volume 1: Guidelines for evaluating the management and operations planning of photovoltaic applications (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Guidelines are provided to the Field Centers for organization, scheduling, project and cost control, and performance in the areas of project management and operations planning for Photovoltaics Test and Applications. These guidelines may be used in organizing a T and A Project Team for system design/test, site construction and operation, and as the basis for evaluating T and A proposals. The attributes are described for project management and operations planning to be used by the Field Centers. Specifically, all project management and operational issues affecting costs, schedules and performance of photovoltaic systems are addressed. Photovoltaic tests and applications include residential, intermediate load center, central station, and stand-alone systems. The sub-categories of system maturity considered are: Initial System Evaluation Experiments (ISEE); System Readiness Experiments (SRE); and Commercial Readiness Demonstration Projects (CRDP).
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-183316 , JPL-5250-3-VOL-1 , NAS 1.26:183316
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  • 39
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    Photovoltaic system criteria documents. Volume 4: Review criteria for photovoltaic applications (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Guidelines are provided for the organization, preparation and conduct of program reviews for photovoltaic applications. These criteria apply to all photovoltaic applications. They include, but are not limited to, the following: (1) Conceptual design review; (2) Preliminary design review; (3) Critical design review; and (4) Operational readiness review. Contract goal's and objectives are met through program monitoring for cost, schedule, and performance for both managerial and technical elements for all PV applications activities.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-183319 , JPL-5250-3-VOL-4 , NAS 1.26:183319
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  • 40
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    Photovoltaic system criteria documents. Volume 2: Quality assurance criteria for photovoltaic applications (1979)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Quality assurance criteria are described for manufacturers and installers of solar photovoltaic tests and applications. Quality oriented activities are outlined to be pursued by the contractor/subcontractor to assure the physical and operational quality of equipment produced is included. In the broad sense, guidelines are provided for establishing a QA organization if none exists. Mainly, criteria is provided to be considered in any PV quality assurance plan selected as appropriate by the responsible Field Center. A framework is established for a systematic approach to ensure that photovoltaic tests and applications are constructed in a timely and cost effective manner.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-183317 , JPL-5250-3-VOL-2 , NAS 1.26:183317
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  • 41
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    Results of a utility survey of the status of large wind turbine development (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Wind energy conversion systems were surveyed from a utility viewpoint to establish the state of the art with regard to: (1) availability of the type of machines; (2) quality of power generation; (3) suitability for electrical grid; (4) reliability; and (5) economics. Of the 23 designs discussed, 7 have vertical axis wind turbines, 9 have upwind horizontal axis turbines, and 7 have downwind horizontal axis turbines.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 363-374
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  • 42
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    Large, low cost composite wind turbine blades (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A woven roving E-glass tape, having all of its structural fibers oriented across the tape width was used in the manufacture of the spar for a wind turbine blade. Tests of a 150 ft composite blade show that the transverse filament tape is capable of meeting structural design requirements for wind turbine blades. Composite blades can be designed for interchangeability with steel blades in the MOD-1 wind generator system. The design, analysis, fabrication, and testing of the 150 ft blade are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 309-324
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  • 43
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    The use of wood for wind turbine blade construction (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The interrelationships between moisture and wood, conditions for dry rot spore activity, the protection of wood fibers from moisture, wood resin composites, wood laminating, quality control, and the mechanical properties of wood are discussed. The laminated veneer and the bonded sawn stock fabrication techniques, used in the construction of a turbine blade with a monocoque 'D' section forming the leading edge and a built up trailing edge section, are described. A 20 foot root end sample complete with 24 bonded-in studs was successfully subjected to large onetime loads in both the flatwise and edgewise directions, and to fatigue tests. Results indicate that wood is both a viable and advantageous material for use in wind turbine blades. The basic material is reasonably priced, domestically available, ecologically sound, and easily fabricated with low energy consumption.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 293-308
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  • 44
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    Evaluation of an operating MOD-OA 200 kW wind turbine blade (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Operating loads and structural damage were monitored during operation of the MOD-OA electric generating system. The turbine was damaged locally between stations 48 and 125 after 2.8 million rotations. Loads due to degraded yaw stiffness and fretting at rib station 48 were identified as primary to this distress. The repaired blades operated an additional 4.8 million rotations without problems.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 239-265
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  • 45
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    Cost of energy evaluation (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The estimated cost per kilowatt hour, the wind resources in the utilities service area, and the reliability of the units are considered in computing the cost of energy of the wind turbine generator system.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 397-402
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  • 46
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    Status of the Southern California Edison Company 3 MW Wind Turbine Generator (WTG) demonstration project (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: To demonstrate the concept of utility scale electricity production from a high wind energy resource, a program was initiated to construct and test a 3 megawatt (3,000 kW) Schachle wind turbine generator near Palm Springs, California. The background and current status of this program are presented along with a summary of future planned program activities.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 355-362
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  • 47
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    Blade design and operating experience on the MOD-OA 200 kW wind turbine at Clayton, New Mexico (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Two 60 foot long aluminum wind turbine blades were operated for over 3000 hours on the MOD-OA wind turbine. The first signs of blade structural damage were observed after 400 hours of operation. Details of the blade design, loads, cost, structural damage, and repair are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Large Wind Turbine Design Characteristics and R and D Requirements; p 225-238
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  • 48
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    Alcoa wind turbines (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An overview of Alcoa's wind energy program is given with emphasis on the the development of a low cost, reliable Darrieus Vertical Axis Wind Turbine System. The design layouts and drawings for fabrication are now complete, while fabrication and installation to utilize the design are expected to begin shortly.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 155-171
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  • 49
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    Specification, siting and selection of large WECS prototypes (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The development of large-scale windpowered systems is outlined. Topics discussed include: prototype specifications development, site selection process, and selection of prototype contractor.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 89-102
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  • 50
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    Design evolution of large wind turbine generators (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: During the past five years, the goals of economy and reliability have led to a significant evolution in the basic design--both external and internal--of large wind turbine systems. To show the scope and nature of recent changes in wind turbine designs, development of three types are described: (1) system configuration developments; (2) computer code developments; and (3) blade technology developments.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Large Wind Turbine Design Characteristics and R and D Requirements; p 25-33
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  • 51
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    Computer modeling of a two-junction, monolithic cascade solar cell (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The theory and design criteria for monolithic, two-junction cascade solar cells are described. The departure from the conventional solar cell analytical method and the reasons for using the integral form of the continuity equations are briefly discussed. The results of design optimization are presented. The energy conversion efficiency that is predicted for the optimized structure is greater than 30% at 300 K, AMO and one sun. The analytical method predicts device performance characteristics as a function of temperature. The range is restricted to 300 to 600 K. While the analysis is capable of determining most of the physical processes occurring in each of the individual layers, only the more significant device performance characteristics are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 267-281
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  • 52
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    An interim report on the NTS-2 solar cell experiment (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Data obtained from the fourteen solar cell modules on the NTS-2 satellite are presented together with a record of panel temperature and sun inclination. The following flight data are discussed: (1) state of the art solar cell configurations which embody improvements in solar cell efficiency through new silicon surface and bulk technology, (2) improved coverslip materials and coverslip bonding techniques, (3) short and long term effects of ultraviolet rejection filters vs. no filters on the cells, (4) degradation on a developmental type of liquid epitaxy gallium-aluminum-arsenide solar cell, and (5) space radiation effects.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 117-129
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  • 53
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    The NASA Lewis Research Center program in space solar cell research and technology (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Progress in space solar cell research and technology is reported. An 18 percent-AMO-efficient silicon solar cell, reduction in the radiation damage suffered by silicon solar cells in space, and high efficiency wrap-around contact and thin (50 micrometer) coplanar back contact silicon cells are among the topics discussed. Reduction in the cost of silicon cells for space use, cost effective GaAs solar cells, the feasibility of 30 percent AMO solar energy conversion, and reliable encapsulants for space blankets are also considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage, 1979; p 1-4
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  • 54
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    Temperature and intensity dependence of the performance of an electron-irradiated (AlGa)As/GaAs solar cell (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The performance of a Hughes, liquid-phase epitaxial 2 centimeter-by-2 centimeter, (AlGa)As/GaAs solar cell was measured before and after irradiations with 1 MeV electrons to fluences of 1 x 10 to the 16th power electrons/sq cm. The temperature dependence of performance was measured over the temperature range 135 to 415 K at each fluence level. In addition, temperature dependences were measured at five intensity levels from 137 to 2.57 mW/sq cm before irradiation and after a fluence of 1 x 10 to the 16th power electrons/sq cm. For the intermediate fluences, performance was measured as a function of intensity at 298 K only.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Frequency and Radiation Damage, 1979; p 217-226
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  • 55
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    High-energy electron-induced damage production at room temperature in aluminum-doped silicon (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: DLTS and EPR measurements are reported on aluminum-doped silicon that was irradiated at room temperature with high-energy electrons. Comparisons are made to comparable experiments on boron-doped silicon. Many of the same defects observed in boron-doped silicon are also observed in aluminum-doped silicon, but several others were not observed, including the aluminum interstitial and aluminum-associated defects. Damage production modeling, including the dependence on aluminum concentration, is presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 185-196
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  • 56
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    Langley program of GaAs solar cells (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A brief overview of the development of GaAs solar cell technology is provided. An 18 to 20 percent AMO efficiency, stability under radiation and elevated-temperature operation, and high power-to-weight ratio are among the factors studied. Cell cost and availability are also examined.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 13-14
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  • 57
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    Modeling of thin, back-wall silicon solar cells (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The performance of silicon solar cells with p-n junctions on the nonilluminated surface (i.e., upside-down or back-wall cells) was calculated. These structures consisted of a uniformly shaped p-type substrate layer, a p(+)-type field layer on the front (illuminated) surface, and a shallow, n-type junction on the back (nonilluminated) surface. A four-layer solar cell model was used to calculate efficiency, open-circuit voltage, and short-circuit current. The effect on performance of p-layer thickness and resistivity was determined. The diffusion length was varied to simulate the effect of radiation damage. The results show that peak initial efficiencies greater than 15 percent are possible for cell thicknesses or 100 micrometers or less. After 10 years of radiation damage in geosynchronous orbit, thin (25 to 50 micrometers thick) cells made from 10 to 100 ohm cm material show the smallest decrease (approximately 10 percent) in performance.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage, 1979; p 73-78
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  • 58
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    Space Shuttle Orbiter AFT heat shield seal (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The evolution of the orbiter aft heat shield seal (AHSS) design, which involved advancing mechanical seal technology in severe thermal environment is discussed. The baseline design, various improvements for engine access, and technical problem solution are presented. It is a structure and mechanism at the three main propulsion system (MPS) engine interfaces to the aft compartment structure. Access to each MPS engine requires disassembly and removal of the AHSS. Each AHSS accommodates the engine movement, is exposed to an extremely high temperature environment, and is part of the venting control of the aft compartment.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 251-259
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  • 59
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    Hydrazine monopropellant reciprocating engine development (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A hydrazine fueled piston engine for providing 11.2 kW was developed to satisfy the need for an efficient power supply in the range from 3.7 to 74.6 kW where existing nonair-breathing power supplies such as fuel cells or turbines are inappropriate. The engine was developed for an aircraft to fly to 21.3 km and above and cruise for extended periods. A remotely piloted aircraft and the associated flight control techniques for this application were designed. The engine is geared down internally (2:1) to accommodate a 1.8 m diameter propeller. An alternator is included to provide electrical power. The pusher-type engine is mounted onto the aft closure of the fuel tank, which also provides mounting for all other propulsion equipment. About 20 hrs of run time demonstrated good efficiency and adequate life. One flight test to 6.1 km was made using the engine with a small fixed-pitch four-bladed propeller. The test was successful in demonstrating operational characteristics and future potential.
    Keywords: STRUCTURAL MECHANICS
    Type: The 13th Aerospace Mech. Symp.; p 1-14
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    Summary of the Orbiter mechanical systems (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Major mechanical systems of the Orbiter space vehicle are summarized with respect to general design details, manner of operation, expected performance, and, where applicable, unique features. A synopsis of data obtained during the five atmospheric flight tests of spacecraft OV-101 and status of the systems for the first orbital spacecraft STS-1 are presented.
    Keywords: STRUCTURAL MECHANICS
    Type: The 13th Aerospace Mech. Symp.; p 219-234
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  • 61
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    System configuration improvement (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Factors involved in the choice of the system configuration for the wind turbine generator are listed. It was found that choices among the many configuration options can be based strictly upon the resulting cost of energy results. Choices made on that basis also lead to reduced analytical complexity, less hardware complexity and reduced program risk. It was also found that many seemingly minor details turn out to have important impacts that are seen only after design, performance and cost-finding were thoroughly probed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 385-396
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  • 62
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    The Boeing MOD-2 wind turbine system rotor (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: External configuration, environmental, and internal design requirements for the 300 foot diameter MOD-2 rotor are discussed, with emphasis on design details, significance of fatigue strength, design development test results, and conclusions of the preliminary design efforts.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 343-354
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    Structural analysis considerations for wind turbine blades (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Approaches to the structural analysis of wind turbine blade designs are reviewed. Specifications and materials data are discussed along with the analysis of vibrations, loads, stresses, and failure modes.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Large Wind Turbine Design Characteristics and R and D Requirements; p 211-224
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    Large wind energy converter: Growian 3 MW (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The main features of the Growian wind energy converter are presented. Energy yield, environmental impact, and construction of the energy converter are discussed. Reliability of the windpowered system is assessed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 121-132
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    Overview of Federal wind energy program (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The objectives and strategies of the Federal wind energy program are described. Changes in the program structure and some of the additions to the program are included. Upcoming organizational changes and some budget items are discussed, with particular emphasis on recent significant events regarding new approvals.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 1-24
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    Summary of GaAs Solar Cell Performance and Radiation Damage Workshop (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The workshop considered the GaAs solar cell capability and promise in several steps: (1) maximum efficiency; (2) space application; (3) major technology problems (AR coating optimization, contacts); (4) radiation resistance; (5) cost and availability; and (6) alternatives. The workshop believes that GaAs solar cells are fast approaching the fulfillment of their potential as candidates for space cells. A maximum efficiency of 20 to 31 percent AMO can be reasonably expected from GaAs based cells, and this may go a little higher with concentration. The use of concentration in space needs to be more carefully evaluated.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 253-254
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    Shallow-homojunction GaAs solar cells (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Single-crystal GaAs shallow-homojunction solar cells on GaAs or Ge substrates, without Ga sub 1-x Al sub x As window layers, that have conversion efficiencies exceeding 20% at AM1 (17% at AMO). Using a simple theoretical model, good fits were obtained between computer calculations and experimental data for external quantum efficiency and conversion efficiency of cells with different values of n+ layer thickness. The calculations not only yield values for material properties of the GaAs layers composing the cells but will also permit the optimization of cell designs for space and terrestrial applications. Preliminary measurements indicate that the shallow-homojunction cells are resistant to electron irradiation. In the best test so far, bombardment with 1 x 10 to the 16th power/sq cm fluence of 1 MeV electrons reduced the short-circuit current by only about 6%.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Frequency and Radiation Damage, 1979; p 227-233
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    Radiation damage in GaAs solar cells (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Recent results of electron and proton irradiation and annealing of GaAs solar cells are presented along with some implications of these results. A comparison between the energy-levels produced by protons and by electrons which are not stopped in the material indicate that the damage produced by protons and electrons may be qualitatively different. Thus, annealing of proton damage may be very different from the annealing of electron damage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 201-207
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    Reverse annealing in radiation-damaged, silicon solar cells (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: In order to understand the results in terms of properties of the radiation induced defects, a combination of diffusion length measurements and defect data obtained from Deep Level Transient Spectroscopy were used. The results indicate that the defect at E sub v + 0.30 eV is responsible for the observed reversed annealing. The defect was identified as a boron-oxygen vacancy complex. This identification is a guide to processing efforts aimed at increasing the concentration of these radiation induced defects.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage, 1979; p 161-171
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    Efficiency of tandem solar cell systems as function of temperature and solar energy concentration ratio (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The results of a comprehensive theoretical analysis of tandem photovoltaic solar cells as a function of temperature and solar concentration ratio are presented. The overall efficiencies of tandem cell stacks consisting of as many as 24 cells having gaps in the 0.7 to 3.6 eV range were calculated for temperatures of 200, 300, 400, and 500 K and for illumination by an AMO solar spectrum having concentration ratios of 1, 100, 500, and 1000 suns. For ideal diodes (A = B = 1), the calculations show that the optimized overall efficiency has a limiting value eta sub opt of approximately 70 percent for T = 200 K and C = 1000; for T = 300 K and C = 1000, this limiting efficiency approaches 60 percent.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 263-265
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    Silicon solar cells for space use: Present performance and trends (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A technology assessment of present performance levels and current fabrication methods and designs is presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 101-104
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    High efficiency cell geometry (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A new silicon solar cell is described which has an array of small-area conduction paths to transport current directly through the wafer to metal electrodes on the back. This design eliminates grid shadowing and many of the other losses inherent in conventional cells. Early experimental units without texturing or antireflection coatings show 13.3% efficiency under air-mass-one illumination insolation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 97-100
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    Design considerations for the Tandem Junction Solar Cell (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Structure and operation of the tandem junction cell (TJC) are described. The impact of using only back contacts is discussed. A model is presented which explains operation of the TJC in terms of transistor action. The model is applied to predict TJC performance as a function of physical parameters.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 79-85
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    Open-circuit voltage improvements in low-resistivity solar cells (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Mechanisms limiting the open-circuit voltage in 0.1 ohm-cm solar cells were investigated. It was found that a rather complicated multistep diffusion process could produce cells with significantly improved voltages. The voltage capabilities of various laboratory cells were compared independent of their absorption and collection efficiencies. This was accomplished by comparing the cells on the basis of their saturation currents or, equivalently, comparing their voltage outputs at a constant current-density level. The results show that for both the Lewis diffused emitter cell and the Spire ion-implanted emitter cell the base component of the saturation current is voltage controlling. The evidence for the University of Florida cells, although not very conclusive, suggests emitter control of the voltage in this device. The data suggest further that the critical voltage-limiting parameter for the Lewis cell is the electron mobility in the cell base.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage, 1979; p 61-70
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    Limiting process in shallow junction solar cells (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: In extending the violet and nonreflective cell technology to lower resistivities, several processes limiting output power were encountered. The most important was the dark diffusion current due to recombination at the front grid contacts. After removal of this problem by reduction of the silicon metal contact area (to 0.14 percent of the total area), the electric field enhanced junction recombination current J sub r was the main limitation. Alteration of the diffusion profile to reduce the junction field is shown to be an effective means of influencing J sub r. The remaining problems are the bulk recombination in the n+ layer and the surface recombination at the oxide-silicon interface; both of these problems are aggravated by band-narrowing resulting from heavy doping in the diffused layer. Experimental evidence for the main limitations is shown, where increased diffusion temperature is seen to reduce both the influence of the front grid contacts and the junction electric field by increasing the junction depth. The potential for further significant improvement in efficiency appears to be high.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 35-36
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    Solar photovoltaic research and development program of the Air Force Aero Propulsion Laboratory (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Progress is reported in the following areas: laser weapon effects, solar silicon solar cell concepts, and high voltage hardened, high power system technology. Emphasis is placed on solar cells with increased energy conversion efficiency and radiation resistance characteristics for application to satellite power systems.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage, 1979; p 5-8
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    Helical grip for the cable cars of San Francisco (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A helical cable car grip to minimize high maintenance costs of San Francisco's cable car operation is presented. The grip establishes a rolling contact between the cable and grip to reduce sliding friction and associated cable wear. The design, development, and testing of the helical cable car grip are described.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 83-93
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    Space Shuttle Orbiter payload bay door mechanisms (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The opening, closing, and latching of the first large clamshell door to operate in space presented some unusual challenges for the mechanism designer of the Space Shuttle Program. The requirements, hardware configuration, design trade-offs, and qualification testing in process to meet the challenge and to make the system operational for the Shuttle orbiter's approaching first orbital flight are described.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 261-269
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    Tests of a protective shell passive release mechanism for hypersonic wind-tunnel models (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A protective shell mechanism for wind tunnel models was developed and tested. The mechanism is passive in operation, reliable, and imposes no new structural design changes for wind tunnel models. Methods of predicting the release time and the measured loads associated with the release of the shell are given. The mechanism was tested in a series of wind tunnel tests to validate the removal process and measure the pressure loads on the model. The protective shell can be used for wind tunnel models that require a step input of heating and loading such as a thin skin heat transfer model. The mechanism may have other potential applications.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 167-181
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    Reliability breakthrough: An antenna deployment/positioning mechanism with electrical and mechanical redundancy (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An Antenna Positioner Mechanism (APM) was developed for deployment of an antenna reflector and for fine granularity closed loop tracking of the antenna in response to RF beacon error signals. By utilizing permanent magnet stepper motors, spur gearheads, irreversible single threat worm/wheel assemblies and a miter gear differential, full electrical and mechanical redundancy was realized. Two versions of this design were generated: one is a weight-optimized design with a clutch for overload protection and one is a more rugged unit without a clutch.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 137-149
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    Load proportional safety brake (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: This brake is a self-energizing mechanical friction brake and is intended for use in a rotary drive system. It incorporates a torque sensor which cuts power to the power unit on any overload condition. The brake is capable of driving against an opposing load or driving, paying-out, an aiding load in either direction of rotation. The brake also acts as a no-back device when torque is applied to the output shaft. The advantages of using this type of device are: (1) low frictional drag when driving; (2) smooth paying-out of an aiding load with no runaway danger; (3) energy absorption proportional to load; (4) no-back activates within a few degrees of output shaft rotation and resets automatically; and (5) built-in overload protection.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 95-110
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    A two-axis pointing system for an orbiting astronomical instrument (1979)
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    Publication Date: 2016-06-07
    Description: The system described was built for incorporation into a solar flare X-ray instrument due to be orbited as one of a number of instruments on the NASA Solar Maximum Mission (SMM) satellite in late 1979. It enables the instrument to be rotated about 2 mutually perpendicular axes in 5 arc-second steps within a range of 7 arc-minutes, thus giving the instrument the capability to map areas of the sun.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 27-38
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    Automatic in-orbit assembly of large space structures (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The automated assembly of a large number of components required for the on-orbit erection of large tetrahedral space platforms is described. The assembly machine is a huge jig in which a multitude of mechanisms must operated continuously in the thermo vacuum environment of space and under the control of computers programmed to command every step of each motion. The concepts are presented to determine the most reliable solution. Continuous operation of mechanisms in space presents many unresolved problems, with regard to lubrication of unprotected devices, such as chain drives, which must maintain reasonable positioning tolerances.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 283-291
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    IUSThrust Vector Control (TVC) servo system (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The IUS TVC SERVO SYSTEM which consists of four electrically redundant electromechanical actuators, four potentiometer assemblies, and two controllers to provide movable nozzle control on both IUS solid rocket motors is developed. An overview of the more severe IUS TVC servo system design requirements, the system and component designs, and test data acquired on a preliminary development unit is presented. Attention is focused on the unique methods of sensing movable nozzle position and providing for redundant position locks.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 271-281
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    Payload installation and deployment aid for Space Shuttle Orbiter spacecraft remote manipulator system (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An aid concept known as the PIDA (Payload Installation and Deployment Aid) is presented as a way to assist the RMS (Remote Manipulator System) by relaxing the accuracy required during payload handling in the payload bay. The aid concept was designed and developed to move payloads through a prescribed path between the confined quarters of the payload bay and a position outside the critical maneuvering area of the Orbiter. A description of the design requirements and the modes of operation of the various functions of the deployment and the docking mechanisms are covered.
    Keywords: STRUCTURAL MECHANICS
    Type: The 13th Aerospace Mech. Symp.; p 235-249
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    Magnetic spring in oscillating mirror linear scanner for satellite camera (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: One of the main difficulties encountered in the development of a multispectral scanner is the realization of an oscillating mechanical device. A magnetic device which is characterized by the absence of friction is presented. The main developments concern the analysis of magnetic forces. A preliminary project of a device which could be used in a satellite is presented.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 183-193
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    Simulation studies of multiple large wind turbine generators on a utility network (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The potential electrical problems that may be inherent in the inertia of clusters of wind turbine generators and an electric utility network were investigated. Preliminary and limited results of an analog simulation of two MOD-2 wind generators tied to an infinite bus indicate little interaction between the generators and between the generators and the bus. The system demonstrated transient stability for the conditions considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Large Wind Turbine Design Characteristics and R and D Requirements; p 375-384
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    The MOD-1 steel blade (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The design, development, fabrication, testing, and transport of two 100 foot metal blades for the MOD-1 WTS are summarized. Because the metal blade design was started late in the MOD-1 system development, many of the design requirements (allocations) were restrictive for the metal blade concept, particularly the maximum weight requirement. The design solutions required to achieve the weight goal resulted in a labor intensive (expensive) fabrication, particularly for a quantity of only two blades manufactured using minimal tooling.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 325-342
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    WTG Energy Systems' Rotor: Steel at 80 Feet (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The design, specifications, and performance of the 80 foot diameter fixed pitch rotor operating on the MP1-200 wind turbine generator installed as part of the Island of Cuttyhunk's electric power utility grid system are described. This synchronous generating system rated 200 kilowatts at 28 mph wind velocity, and produces constant 60 Hz, 480 VAC current at +/- 1 percent accuracy throughout the machine's operating range. Future R & D requirements and suggestions are included with cost data.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 285-292
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    Design, fabrication, and test of a steel spar wind turbine blade (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The design and fabrication of wind turbine blades based on 60 foot steel spars are discussed. Performance and blade load information is given and compared to analytical prediction. In addition, performance is compared to that of the original MOD-O aluminum blades. Costs for building the two blades are given, and a projection is made for the cost in mass production. Design improvements to reduce weight and improve fatigue life are suggested.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Large Wind Turbine Design Characteristics and R and D Requirements; p 267-284
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    Fabrication of extruded vertical axis turbine blades (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Important characteristics of the extruded aluminum blade for the Vertical Axis Wind Turbine are presented. Their weight, structural strength, shape, and maintainability are pointed out.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 193-204
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    Design Characteristics of the 224 kW Magdalen Islands VAWT (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The evolution of the main design features of the Magdalen Islands vertical axis wind turbine (VAWT) is described. The turbine has a rotor height of 120 ft (36.58 m) and diameter 80 ft (24.38 m). It was operated as a joint project between NRC and Hydro-Quebec in grid-coupled mode from July 1977 to July 1978 when the rotor was destroyed in an accident. The accident, although unfortunate, tested the basic integrity of the design in a gross overspeed condition, and the rotor is being rebuilt with minor modifications. Some directions for future VAWT research are suggested.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 143-154
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    The Danish large wind turbine program (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A brief description of the Danish wind energy program and its present status is given. Results and experiences from tests on the Gedser windmill (200 kW) are presented. The key results are presented from the preliminary design study and detailed design of two new WECS (630 kW each) is described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Large Wind Turbine Design Characteristics and R and D Requirements; p 103-120
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    Radiation effects in GaAs AMOS solar cells (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The results of radiation damage produced in AMOS (Antireflecting-Metal-Oxide-Semiconductor) cells with Sb2O3 interfacial oxide layers by 1-MeV electrons are presented. The degradation properties of the cells as a function of irradiation fluences were correlated with the changes in their spectral response, C-V, dark forward, and light I-V characteristics. The active n-type GaAs layers were grown by the OM-CVD technique, using sulfur doping in the range between 3 x 10 to the 15th power and 7 x 10 to the 16th power/cu cm. At a fluence of 10 to the 16th power e/sq cm, the low-doped samples showed I sub sc degradation of 8% and V sub oc degradation of 8%. The high-doped samples showed I sub sc and V sub oc degradation of 32% and 1%, respectively, while the fill factor remained relatively unchanged for both. AMOS cells with water vapor-grown interfacial layers showed no significant change in V sub oc.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Frequency and Radiation Damage, 1979; p 235-244
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    Radiation damage in high-voltage silicon solar cells (1979)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Three types of open circuit high voltage solar cells were tested to determine their performance after exposure to 1 MeV electron irradiations. The cells with a relatively deep n-type emitter were more susceptible to radiation damage than other high open circuit high voltage cells. The use of diffused or ion implanted junctions leads to open circuit high voltage cell designs that are less susceptible to radiation damage. These latter two types of cells show degradations that are typical of the 0.1 ohm-cm material from which they are fabricated. Furthermore, exposure to ionizing radiation causes oxide degradation and decreased cell performance in cells that depend on a charged oxide to achieve significant cell properties. Hence, the combination of a charged oxide and a relatively deep n-type emitter is not recommended for incorporation into a cell designed for use in the particulate radiation environment of space.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage, 1979; p 137-143
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    Unfolding the air vanes on a supersonic air-launched missile (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: ASALM (Advanced Strategic Air-Launched Missile) is a supersonic air vehicle designed to be air-launched from a carrier aircraft. The four aft aerodynamic control vanes are folded to maximize the number of missiles carried on-board. The unfolding (erection) system must be small, energetic, fast, and strong. The materials selected and problems that arose during development of the unfolding system are described.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 207-217
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  • 97
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    On the design of an adjustable high precision latching hinge (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The design and test details of a high precision hinge and locking mechanism created principally in support of the Lockheed space deployable Flexrib Parabolic Antenna concept are presented. These developed improvements in the detail design of ultra-precise rib hinge and contour adjustment mechanisms will allow radio frequency antenna reflectors to expand into the 15-50 meter diameter size class and to support the .013 mm. deployment repeatability tolerance required to support the 12+ GHz frequency range.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 127-136
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  • 98
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    Unknown
    A telescopic jib for continuous adjustment (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: For special space applications, e.g. for experiments distant from any orbital platforms or manipulators a new kind of jibs with extreme extension capacity has to be designed. Considering the requirements, the telescopic principle is found to be the most promising. For the choice of the stiff structure, design criteria are evaluated. Special effort deals with the drive system. An electromechanical system can satisfy the requirements. First results of the development of such a drive are presented. The most significant features are: A telescopic assembly of tubes which can be mutually moved by a short spindle in the center of the package. An elastically suspended screw is located at the bottom of each tube. For the jib extension, these screws will be linked with the spindle. The control of their sequence and the adjustment of tubes in mutual end positions are performed by latches. A functional model proved the basic idea.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 49-58
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  • 99
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    Unknown
    Development of the Trident 1 aerodynamic saike mechanism (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The Aerospike drag reduction mechanism was designed and developed for use on the Trident I submarine launched ballistic missile. This mechanism encounters a unique combination of environments necessitating unique design solutions to ensure satisfactory operation over its design life. The development of the Aerospike is reviewed emphasizing the unique and interesting problems encountered and their solutions.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 39-48
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  • 100
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    Gimbal bearing design considerations and friction control (1979)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The design considerations of bearing selection, bearing fits, bearing installation, and thermal control are discussed for a gimbal with a high stiffness, low friction torque requirement. Tradeoffs between a quad set of small diameter spread apart or a large diameter bearing pair resulted in a cleaner, lighter, stiffer unit with the latter selection. Bearing fits were designed to eliminate clearances with tolerances of .00127 mm 00005 in) on the bearing shafts and housings. The problems in metrology are discussed and a perferred technique for measurement of small cross-section bearings described. A technique for installation to assure proper seating of the bearing is offered. Where transient thermal conditions are involved, a method of controlling bearing friction by active control of bearing temperature gradients including the use of bearing unload test curves is described.
    Keywords: STRUCTURAL MECHANICS
    Type: NASA. Johnson Space Center The 13th Aerospace Mech. Symp.; p 71-81
    Format: application/pdf
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