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An analysis and evaluation was made of the operating parameters of the shuttle electrical power distribution circuit under load conditions encountered during a normal Sortie 2 Mission with emphasis on main periods of liftoff and landing.
The ERDA/LeRC Photovoltaic Systems Test Facility (STF) provides a vital support function to the overall ERDA National Solar Photovoltaic Program. It allows preliminary investigation and checkout of components, subsystems, and complete photovoltaic systems before installation in actual service. The STF can also be used to determine optimum system configurations and operating modes. A facility description is presented, taking into account the solar cell array, the energy storage equipment, the power conditioning equipment, electric utility distribution network and loads, and instrumentation and data acquisition systems. Safety procedures which have been set up for maintenance and inspection of the solar array are discussed. Attention is also given to a number of investigations regarding the effect of environmental factors on solar cell array operation.
Some results for the bivariate normal distribution analysis are presented. Computer programs for conditional normal probabilities, marginal probabilities, as well as joint probabilities for rectangular regions are given: routines for computing fractile points and distribution functions are also presented. Some examples from a closed circuit television experiment are included.
The survey measured, over virtually the entire galactic plane, the distribution and basic physical conditions of the coolest dust component of the interstellar medium. The instrument designed for observations of extended, low surface brightness continuum emission consisted of a balloon borne, gyro stablized, 1.2 m Cassegrain telescope and a liquid cooled photometer. The design, integration, tests, and flight operation of the survey are presented.
A model has been developed to test the hypothesis that the observed seasonal and latitudinal distribution of water on Mars is controlled by the sublimation and condensation of surface ice deposits in the Arctic and Antarctic, and the meridional transport of water vapor. Besides reproducing the observed water vapor distribution, the model correctly reproduces the presence of a large permanent ice cap in the Arctic and not in the Antarctic. No permanent ice reservoirs are predicted in the temperate or equatorial zones. Wintertime ice deposits in the Arctic are shown to be the source of the large water vapor abundances observed in the Arctic summertime, and the moderate water vapor abundances in the northern temperate region. Model calculations suggest that a year without dust storms results in very little change in the water vapor distribution. The current water distribution appears to be the equilibrium distribution for present atmospheric conditions.
The relativistic cyclotron resonance condition for right-handed extraordinary mode waves defines an ellipse in velocity space. The position of the center and size of the semiminor axis of this ellipse are functions of the plasma frequency, gyrofrequency, wave frequency, and wave normal angle. The effect of varying these parameters on the position and size of the resonance contour is analyzed. The results show that as the wave normal angle decreases, the semiminor axis increases in size and as the plasma frequency to gyrofrequency ratio decreases, the minimum energy for resonating electrons decreases and the maximum wave normal angle allowed by the resonance condition increases. Also, as the wave frequency to gyrofrequency ratio increases, the center of the resonance ellipse moves away from the origin. The relativistic resonance condition and the electron distribution in velocity space obtained by the S3-3 satellite are used to calculate numerically growth rates for the terrestrial auroral kilometric radiation. It is shown that the loss cone region of the electron distribution can give rise to growth rates for the extraordinary mode that are sufficiently large to account for the observed radio emission intensities.
This study has examined the level of transonic maneuver performance that can be achieved by the use of three-dimensional transonic theory. The FLO-27 code of Jameson and Caughey (1977) was used to lower maneuver drag by the reduction of shock strength on the wing upper surface. A design procedure was used to provide a set of guidelines for the iterative application of FLO-27 during the wing design process. The fighter configuration utilized had a leading-edge sweep of 45 deg and an aspect ratio of 3.28. Tests were conducted at Mach numbers from 0.60 to 0.95 and angles of attack from -5 to 18 deg. The accurate prediction of wing shock systems required the inclusion of fuselage effects in the theory. The FLO-27 code gave a reasonable estimate of the experimental wing pressure distributions at transonic maneuver conditions in the region of the wing where the flow was attached. For Mach numbers between 0.60 and 0.95 and lift coefficients near 0.9, a wing designed by the use of FLO-27 showed substantially lower drag than an empirically developed, supercritical maneuver wing and a maneuver wing designed primarily by two-dimensional transonic theory. For some maneuver conditions, the drag of the two-dimensional design was somewhat lower.
New observations of the 3000 A bump in quasars are presented and some simple considerations regarding its physical origin are addressed. Absolute spectrophotometry of 30 quasars with redshifts between 0.53 and 0.70 was obtained with the multichannel spectrometer on the 5 m Hale telescope with a rest wavelength coverage of 2000-5000 A. The continuum observations are well represented by a single power law plus a smooth, broad bump and superposed Fe II multiplets. The strength of the bump correlates fairly well with that of H-beta but poorly with those of the Mg II and Fe II lines. Models consisting of a power law and optically thick hydrogen continua with temperatures of about 12,000 K, and Balmer-edge optical depths equal to three fit the observed energy distributions well. The physical conditions and continuum emission of a dense slab of hydrogen heated by gamma rays are analyzed.
Supercritical technology has been applied to the design of a forward-swept-wing fighter configuration, and an assessment has been made of the relative performance of forward versus aft sweep. The wing and canard for this forward-swept wing configuration were designed for transonic maneuver by the use of a transonic computational analysis method and a transonic design procedure. The computational method calculates the transonic flow over a canard-wing-fuselage combination so that the strong transonic induced-flow effects of the canard on the wing are taken into account. A model of this configuration was constructed and was tested in the Langley 16-Foot Transonic Tunnel. The transonic theory gave a reasonably good estimate of the wing pressure distributions at transonic maneuver conditions. Comparison of this configuration with an equivalent aft-swept wing configuration showed that, at a Mach number of 0.9 and a lift coefficient of 0.9, the two configurations have essentially the same drag. This forward-swept wing configuration was also found to have very good maneuver performance relative to the Rockwell International HiMAT highly-maneuverable aircraft configuration.
Following the solar proton event (SPE) of July 13, 1982, an increase in the strength of nitric oxide Gamma bands was observed in spectral scans of the atmospheric albedo made by the solar backscattered ultraviolet instrument on Nimbus 7. Analysis of the (10), (01), and (02) Gamma band strengths allow an estimate to be made of the cumulative amount of nitric oxide above an altitude of 50 km. An increase in nitric oxide in southern hemisphere high latitudes following the SPE amounting to about 5 x 10 to the 14th molecules per sq cm above an altitude of approximately 50 km is observed. The observed increase persists until the middle of September. A similar increase is not observed in the northern hemisphere, indicating that under summer conditions the mesospheric/thermospheric NO distribution returns to normal within a few days after the end of an SPE.
A transonic computational analysis method and a transonic design procedure have been used to design the wing and the canard of a forward-swept-wing fighter configuration for good transonic maneuver performance. A model of this configuration was tested in the Langley 16-Foot Transonic Tunnel. Oil-flow photographs were obtained to examine the wind flow patterns at Mach numbers from 0.60 to 0.90. The transonic theory gave a reasonably good estimate of the wing pressure distributions at transonic maneuver conditions. Comparison of the forward-swept-wing configuration with an equivalent aft-swept-wing-configuration showed that, at a Mach number of 0.90 and a lift coefficient of 0.9, the two configurations have the same trimmed drag. The forward-swept wing configuration was also found to have trimmed drag levels at transonic maneuver conditions which are comparable to those of the HiMAT (highly maneuverable aircraft technology) configuration and the X-29 forward-swept-wing research configuration. The configuration of this study was also tested with a forebody strake.
Scattering parameters for ensembles of aspherical ice and liquid hydrometeors were calculated at Psi = 50 deg for frequencies of 37.0, 50.3, and 85.6 GHz. Hydrometeors were assumed to be oblate spheroids whose semiminor axes were aligned at Psi = 0 deg. The angle of 50 deg is determined by the viewing angle of recent satellite-borne radiometers. Backscattering phase functions and extinction coefficients at Psi = 0 deg were also computed at 18.0, 37.0, and 85.6 GHz to provide information for future nadir scanning radars. The hydrometeors were assumed to be characterized by Marshall-Palmer (1948) size distributions. The extended boundary condition method was used to calculate the extinction and backscattering coefficients as well as the albedo for single scattering and the asymmetry factor of the phase function. Results are fitted to simple functions of the rainfall rate. Some comparisons intended to illustrate the differences and similarities of these results with those obtained from equal volume spheres are also presented.
Thin-film resistance gages were used to measure cylinder surface heat-transfer rates in the near wake of the Aeroassist Flight Experiment vehicle configuration, while surface-streamline directions were ascertained by the oil-flow techniques under the same configuration and test conditions. Both heat transfer distributions and flow over the entire cylinder surface were influenced by impingement of that portion of the free shear layer originating at the forebody shoulder in the upper symmetry plane. Heating rate distributions predicted with a Navier-Stokes solver computer code were in general agreement with measurements.
An evaluation of single-cycle and multiple-cycle proof testing (MCPT) strategies for SSME components is described. Data for initial sizes and shapes of actual SSME hardware defects are analyzed statistically. Closed-form estimates of the J-integral for surface flaws are derived with a modified reference stress method. The results of load- and displacement-controlled stable crack growth tests on thin IN-718 plates with deep surface flaws are summarized. A J-resistance curve for the surface-cracked configuration is developed and compared with data from thick compact tension specimens. The potential for further crack growth during large unload/reload cycles is discussed, highlighting conflicting data in the literature. A simple model for ductile crack growth during MCPT based on the J-resistance curve is used to study the potential effects of key variables. The projected changes in the crack size distribution during MCPT depend on the interactions between several key parameters, including the number of proof cycles, the nature of the resistance curve, the initial crack size distribution, the component boundary conditions (load vs. displacement control), and the magnitude of the applied load or displacement. The relative advantages of single-cycle and multiple-cycle proof testing appear to be specific, therefore, to individual component geometry, material, and loading.
The nature and the spatial distribution of cumuli within an unforced cumulus cloud field are investigated. The thermodynamic effects of convection are quantified as functions of changes of convective available potential energy (CAPE) induced by the convective overturning, and the time rate of change of CAPE is parameterized in terms of a kernel of influence or stabilization function. A three-dimensional cloud model is used to infer and quantify stabilization functions by performing single-cloud experiments. On the basis of the results obtained, a new hypothesis with respect to the spatial distribution of cumuli is postulated, which states that, under completely homogeneous external conditions and assuming a spatially random distribution of cloud-triggering mechanisms, the spatial distribution of cumuli in the resulting cloud field must be regular, as opposed to either random or clustered, because cumulus clouds tend to reduce the available energy for convection, thereby inhibiting further convection nearby.
The effect of a prior stretching of an aluminum alloy Al-5.3Cu-1.4Li-0.4Ag-0.4Mg-0.17Zr (in wt pct) on the microstructure that develops during aging of this alloy was investigated by comparing TEM and SAD observations and hardness curves with results for the unstretched alloy. The results suggest that stretching introduces a significant number of dislocations which may act as vacanacy sinks by sweeping vacancies away and thereby decreasing the vacancy concentration available for influencing the natural aging response. In the stretched and near-peak aged condition, a fine homogeneous distribution of T1, theta-prime, and S-prime phases were observed in an alpha solid solution matrix. Upon overaging, virtually all of the theta-prime and most of the S-prime phases were found to dissolve, leaving behind a microstructure of T1 precipitates.
Fractional cloudiness influences the planetary boundary layer (PBL) by controlling the cloud-top radiative cooling rate, and regulating the buoyant production and consumption of turbulence kinetic energy. Betts, Hanson, and Albrecht have modeled partly cloudy PBLs by assuming a single family of convective circulations. The same idealized model has been used in observational studies, based on conditional sampling and/or joint distribution functions, by Lenschow, Albrecht, and others. This approach is extended. None of these authors has proposed a method to determine the fractional area covered by rising motion; finding such a method was a key objective of the present study.
The CELSS Breadboard Project is described, noting that it was initiated to study aspects of a CELSS for long-term space missions. Topics for extensive investigation included air and water regeneration, engineering control, and food production. The many options available for growing food crops in commercial plant growth chambers were investigated and the best of this information was translated to the Biomass Production Chamber (BPC). The chamber contains 20 sq m of crop growing area under 96 400 W HPS lamps; sixteen 0.25 sq m plant growth trays used on each of four growing shelves for a total of 64 trays; and one 256-L nutrient solution reservoir with the appropriate continuous-flow, thin-film plumbing for each shelf. A heating, ventilating, and air-conditioning system maintains atmospheric conditions and serves to distribute oxygen and carbon dioxide and maintain pressure at 12 mm of water. The control and monitoring subsystem, which uses a programmable logic controller, manages the BPC subsystems.