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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Interconnection tabs in a nine-solar-cell array have been soldered simultaneously with radiant heat. Cells and tabs are held in position for soldering by sandwiching them between compliant silicone-rubber vacuum platen and transparent polyimide sealing membrane. Heat lamps warm cells, producing smooth, flat solder joints of high quality.
Projection of one drawing on another with projected image adjusted to have same scale as other drawing permits quick comparisons of such features as relative sizes of parts and clearance or interferences in assemblies. Technique uses standard overhead projector and transparency of one drawing to project an enlarged image, the scale of which matches scale of second drawings. Image may be traced directly onto copy of second drawing.
Ampoule charge heating system exploits spectral properties of blackbody radiation and ampoule material transparency to heat charge to high temperature. Cooling gas prevents softening of outside wall of ampoule. Use of proposed method may be limited by tendency of silica (or any other viteous material) to devitrify on prolonged exposure to temperatures near softening point.
A review of techniques for obtaining contour information from stereo pairs is given. Photogrammetric principles including a description of stereoscopic vision are presented. The use of conventional contour generation methods, such as the photogrammetric plotting technique, electronic correlator, and digital correlator are described. Coherent optical techniques for contour generation are discussed and compared to the electronic correlator. The optical techniques are divided into two categories: (1) image plane operation and (2) frequency plane operation. The description of image plane correlators are further divided into three categories: (1) image to image correlator, (2) interferometric correlator, and (3) positive negative transparencies. The frequency plane correlators are divided into two categories: (1) correlation of Fourier transforms, and (2) filtering techniques.
The primary features of the overall study are encompassed and an evaluation of an automation system is presented. Objectives of the study are described, methods of evaluation are summarized and conclusions about the system's feasibility are presented. Also included is a brief history of fingerprint automation activities within the FBI, the organization of the FBI, a bibliography of documents and records, a data dictionary and a reference set of all of the transparencies presented throughout the study.
The III-V semiconductor materials system that was selected for continued cascade cell development was the AlGaAs cell on GaAs cell structure. The tunnel junction used as transparent ohmic contact between the top cell and the bottom cell continued to be the central difficulty in achieving the program objective of 25 percent AMO efficiency at 25 C. During the tunnel junction and top cell developments it became apparent that the AlGaAs cell has potential for independent development as a single junction converter and is a logical extension of the present GaAs heteroface technology.
A decomposition of the molecular energy is presented that is motivated by the atom superposition and electron delocalization physical model of chemical binding. The energy appears in physically transparent form consisting of a classical electrostatic interaction, a zero order two electron exchange interaction, a relaxation energy, and the atomic energies. Detailed formulae are derived in zero and first order of approximation. The formulation extends beyond first order to any chosen level of approximation leading, in principle, to the exact energy. The structure of this energy decomposition lends itself to the fullest utilization of the solutions to the atomic sub problems to simplify the calculation of the molecular energy. If nonlinear relaxation effects remain minor, the molecular energy calculation requires at most the calculation of two center, two electron integrals. This scheme thus affords the prospects of substantially reducing the computational effort required for the calculation of molecular energies.
With the interpretation of isochromatic and isoclinic fringes in transparent, birefringent, orthotropic composites established, efforts were in progress to determine the individual values of the principal stresses or strains. Several methods utilize the photoelastic results only partially and rely on numerical procedures. Others attempt to obtain the required information based entirely on experimental data. The classical oblique incidence technique as applied to transversely isotropic birefringent composites, is presented. The proposed extension is verified by applying it to the problem of an orthotropic half-plane subjected to an edge-load.
Rocket borne probes and incoherent scatter radar were demonstrated to be effective methods of studying the structure of midlatitude sporadic E layers. Layers are formed when metal ions are converged vertically in a wind shear to produce a local enhancement of electron density. Rocket and radar observations show that the layers may occassionally have complex structure produced by an unstable wind shear. The partial transparency to radio waves of sporadic E layers is shown to be due to localized regions of high electron density.
A fluorescence radiation converter is described which includes a substantially undoped optically transparent substrate and a waveshifter coating deposited on at least one portion of the substrate for absorption of radiation and conversion of fluorescent radiation. The coating is formed to substantially 1000 g/liter of a solvent, 70 to 200 g/liter of an organic polymer, and 0.2 to 25 g/liter of at least one organic fluorescent dye. The incoming incident radiation impinges on the coating. Radiation is absorbed by the fluorescent dye and is re-emitted as a longer wavelength radiation. Radiation is trapped within the substrate and is totally internally reflected by the boundary surface. Emitted radiation leaves the substrate ends to be detected.
A zoom stereoscope was used to interpret aerial color photographs of the Finger Lakes region near Bath, New York, and areas of conifers were delineated on acetate sheets. Scale was determined for each photograph and units were converted to acres. Photographically enlarged positive transparencies of imagery from LANDSAT bands 5,6, and 7 for the southern portion of the study area were placed in a cold additive viewer and registered with each other to provide a composite image. A green filter was used on band 5, blue on band 6, and red on band 7. Conifers appeared at dark, reddish purple. Average was determined using a grid. Results show that the total confer stands within 50 miles of Bath is approximately 176,000 acres of which 60,000 acres are in Pennsylvania. The study was conducted to determine the feasibility of locating a particleboard manufacturing firm in the Southern Tier.
The meeting gave PTTI managers, systems engineers, and program planners a transparent view of the state-of-the-art, an opportunity to express needs, a view of important future trends, and a review of relevant past accomplishments. The PTTI users were provided with new and useful applications, procedures, and techniques. Emphasis is placed on military applications and avionics.
An imaging system comprises a multi-channel matrix array of CCD devices wherein a number of sensor cells (pixels) in each channel are subdivided and operated in discrete intercoupled groups of subarrays with a readout CCD shift register terminating each end of the channels. Clock voltages, applied to the subarrays, selectively cause charge signal flow in each subarray in either direction independent of the other subarrays. By selective application of four phase clock voltages, either one, two or all three of the sections subarray sections cause charge signal flow in one direction, while the remainder cause charge signal flow in the opposite direction. This creates a form of selective electronic exposure control which provides an effective variable time delay and integration of three, six or nine sensor cells or integration stages. The device is constructed on a semiconductor sustrate with a buried channel and is adapted for front surface imaging through transparent doped tin oxide gates.
Digitally processed Seasat synthetic aperture radar (SAR) imagery of the Denver, Colorado area was examined to assess its potential for mapping urban land cover and the compatibility of SAR derived classes with those described in the U.S. Geological Survey classification system. The entire scene was interpreted to generate a small-scale land cover map. In addition, six subscene enlargements representative of urban land cover categories extant in the area were used as test sites for detailed analysis of land cover types. Two distinct approaches were employed and compared in examining the imagery - a visual interpretation of black-and-white positive transparencies and an automated-machine/visual interpretation. The latter used the Image 100 interactive image analysis system to generate land cover classes by density level slicing of the image frequency histogram.
A profile of the average normal optical depth for Saturn's rings between 1.22 and 2.35 Saturn radii is examined. In the A and B rings, horizontal inhomogeneities make these values deceptive. A thinner component of the B ring with an optical depth below 0.08 covers up to 4% of its surface area. In the A ring, the more transparent component covers more than 7% of its area and has an optical depth greater than 0.10. These thinner parts of the rings would rarely be apparent from earth based observations. The particles of the C ring are larger than 15 microns and differ from those of the B and A rings. The C ring is either homogeneous with high albedo and forward scattering phase functions, or shows a gradient in albedo with distance from Saturn. Polarimetry of Saturn's ring provides only an upper limit (below 15%) which is consistent with ground-based predictions. Polarization in the outer A ring is negative.
Two excellent low-resolution spectra show an absorption line of equivalent width 3 A, near 1391 A, in the typical DA (hydrogen atmosphere) white dwarf 40 Eri B. The line is confirmed by a high-resolution spectrum and is the first seen in any DA star. Ultraviolet fluxes and the profile of Lyman-alpha confirm an effective temperature near 17,000 K. If the line is Si IV, it requires a temperature near 40,000 K. Unattractive possibilities are a hot circumstellar absorbing envelope dependent on accretion from companions, or formation at large optical depth in a transparent atmosphere with high Si/H. A suggestion that H2 should be considered leads to the possible interpretation as the (0, 5) transition of the Lyman band, formed at small optical depth. The band should be stronger in cooler DAs.
Upper limits on the number of fast electrons streaming through and escaping from a plasma whose electrons have been heated to approximately 100 billion K and confined by a collisionless ion-acoustic thermal conduction front are determined. It is shown that such a front is fairly transparent to fast electrons with velocities much larger than the thermal velocity because the anisotropic ion-acoustic waves cannot scatter them, making them collisionless on a scale much larger than the thickness of the front. The collisionless analog of the collisional thermoelectric field is derived self-consistently and shown to offer a significant impediment to fast electrons because they must climb over a larger potential barrier than in the collisional case. The only factors limiting the escape of electrons able to surmount this barrier are their rate of production and the requirement that they carry less heat flux than the maximum heat flux allowable. The rate of production is determined for the case of a Maxwellian whose tail is being filled collisionally.
Timings of occultation events observed at Perth, Australia during the appulse of Uranus to SAO 158687 are presented. In addition to pre- and post-appulse observations of the alpha ring, a search of the data confirms events by the '4', '5', and '6' rings on the pre-appulse side of Venus, and the '5' and beta rings on the post-appulse side. A table of other suspected events obtained from a statistical search of the data down to the same level of significance as the '4', '5', and '6' events is presented. A fairly strong 'event', so far unconfirmed, is noted near the 5:1 Miranda resonance orbit. Examination of the light curves at high time resolution indicates that the alpha ring was, during this aspect, about 10 km in radial extent and about 50% transparent.