Photon-coupled isolation switch Final report, 1 Jan. 1966 - 31 Mar. 1968
Electro-optic techniques for developing miniature photon-coupled integrated circuit
Bonin, E. L.↗
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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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Investigation of laser dynamics, modulation and control by means of intra-cavity time varying perturbation Quarterly status report, 1 Nov. 1969 - 31 Jan. 1970
Tunable optical sources obtained by means of nonlinear optical techniques
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Investigation of laser dynamics, modulation and control by means of intra-cavity time varying perturbation Quarterly status report, 1 Feb. - 30 Apr. 1970
Tunable optical sources by means of nonlinear optical techniques
Harris, S. E.↗
Mineralogy of the lunar clinopyroxenes, augite and pigeonite
Apollo 11 lunar rocks and fines, examining clinopyroxenes augite and pigeonite by single crystal X ray diffraction microprobe optical and electron optical techniques
Bence, A. E.↗
Study of rectangular-guide-like structures for millimeter wave transmission
Effects of surface roughness on conduction losses at millimeter wavelengths determined by optical techniques and resonator quality factors
Tischer, F. J.↗
Research in space physics at the University of Iowa
Satellite observations, radio-astronomical and optical techniques, and problems in plasma physics associated with effects of energetic particles in outer space
Van Allen, J. A.↗
Characteristics of the optical radiation from Kaufman thrusters
The optical radiation from plasma discharges of electron-bombardment mercury-ion thrusters was investigated. Spectrographic measurements indicated that the discharge was composed primarily of mercury atoms and singly charged ions. Excitation spectra of doubly charged mercury ions was measured to obtain the fraction of such ions in the discharge. Accomplishments of spectroscopic measurements of a hollow cathode thruster included the identification of two diagnostic lines in the mercury spectrum and the interpretation of the spectral amplitudes in terms of a superposition of primary and Maxwellian electron distributions. Potential application of optical techniques to thruster control applications was also suggested by the measurements.
Milder, N. L.↗
A multiple-beam spherical reflector antenna
A spherical reflector with multiple feeds is considered for application in communications satellite systems. Data are presented which show that spherical reflectors possessing relatively high gain (40 db) and very small phase path error are feasible. A design of a spherical reflector utilizing corrugated horn feeds is considered. Radiation patterns are computed using the physical-optics technique. The designed antenna is approximately 60 lambda in diameter. Calculations performed for this antenna with three beams indicate that each beam has a gain of about 42 db, a beamwidth of 1.4 deg, and sidelobes that can be expected to be at least 28 db down. These results indicate that the feature of low sidelobes makes the spherical reflector a consideration for a multiple-beam communications satellite antenna.
Woo, R.↗
Whitecap coverage from aerial photography
A program for determining the feasibility of deriving sea surface wind speeds by remotely sensing ocean surface radiances in the nonglitter regions is discussed. With a knowledge of the duration and geographical extent of the wind field, information about the conventional sea state may be derived. The use of optical techniques for determining sea state has obvious limitations. For example, such means can be used only in daylight and only when a clear path of sight is available between the sensor and the surface. However, sensors and vehicles capable of providing the data needed for such techniques are planned for the near future; therefore, a secondary or backup capability can be provided with little added effort. The information currently being sought regarding white water coverage is also of direct interest to those working with passive microwave systems, the study of energy transfer between winds and ocean currents, the aerial estimation of wind speeds, and many others.
Austin, R. W.↗
Study of a comet rendezvous mission. Volume 2: Appendices
Appendices to the comet Encke rendezvous mission consider relative positions of comet, earth and sun; viewing condition for Encke; detection of Taurid meteor streams; ephemeris of comet Encke; microwave and optical techniques in rendezvous mission; approach instruments; electrostatic equilibrium of ion engine spacecraft; comet flyby data for rendezvous spacecraft assembly; observations of P/Encke extracted from a compilation; and summary of technical innovations.
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Conical quadreflex antenna analytical study
A method for evaluating the performance of a four-reflection or quadreflex antenna is reported. Geometrical optics was used initially to determine the ideal feed pattern required to produce uniform illumination on the aperture of the conical reflector and the reverse problem of quickly finding the aperture illumination given an arbitrary feed pattern. The knowledge of the aperture illumination makes it possible to compute the antenna efficiency, which is useful for comparing antenna performance during tradeoff studies. Scattering calculations, using physical optics techniques, were then used to more accurately determine the performance of a specific design.
Cramer, P. W., Jr.↗
Basic failure mechanisms in advanced composites
The fundamental failure mechanisms which result from the interaction of thermal cycling and mechanical loading of carbon-epoxy composites were studied. This work was confined to epoxy resin uniderictionally reinforced with HTS carbon fibers, and consists of first identifying local fiber, matrix and interface failure mechanisms using the model composite specimen containing a small number of fibers so that optical techniques can be used for characterization. After the local fracture process has been established for both mechanical loading and thermal cycling, engineering composite properties and gross fracture modes are then examined to determine how the local events contribute to real composite performance. Flexural strength in high fiber content specimens shows an increase in strength with increased thermal cycling. Similar behavior is noted for 25 v/o material up to 200 cycles; however, there is a drastic reduction after 200 cycles indicating a major loss of integrity probably through the accumulation of local cleavage cracks in the tensile region.
Mazzio, V. F.↗
Spectral reflectance and emittance of particulate materials. I - Theory. II - Application and results
The sizes, shapes, and complex refractive indices of particles are calculated in a study of the IR spectral reflectance of a semiinfinite medium composed of irregular particles of different materials. Geometric optics techniques with corrections for additional absorption due to particle edges and asperities is used in scattering and absorption calculations for particles larger than the wavelength. A Lorentz-Lorenz model is used to derive the averaged complex index of the medium, assuming that its individual particles are ellipsoids. Experimental results obtained on a Michelson interferometer for the spectral emittance of particulate mineral materials are compared with theoretical results. Good agreement between the experimental and theoretical results suggests the applicability, in remote IR spectroscopy, of the theoretical concepts applied in this study.
Emslie, A. G.↗
Testing methods and techniques: A compilation
Mechanical testing techniques, electrical and electronics testing techniques, thermal testing techniques, and optical testing techniques are the subject of the compilation which provides technical information and illustrations of advanced testing devices. Patent information is included where applicable.
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Research in space physics at the University of Iowa
Various research projects in space physics are summarized. Emphasis is placed on: (1) the study of energetic particles in outer space and their relationships to electric, magnetic, and electromagnetic fields associated with the earth, the sun, the moon, the planets, and interplanetary medium; (2) observational work on satellites of the earth and the moon, and planetary and interplanetary spacecraft; (3) phenomenological analysis and interpretation; (4) observational work by ground based radio-astronomical and optical techniques; and (5) theoretical problems in plasma physics. Specific fields of current investigations are summarized.
Vanallen, J. A.↗
The stability of liquid dispersions in low gravity
The stability of three different dispersions of oil and water prepared on Skylab 4 is compared with the same dispersions made on earth. The stability of the emulsions has been studied by two independent optical techniques. An analysis of the data indicates that all the investigated emulsions were stable over a period of 10 hr, whereas the fluids separated completely on earth in 10 sec. This experiment indicates that the rate of coalescence in low gravity is at least 3 millionths times that on earth. A knowledge of the coalescence rate in low gravity is important in the solidification of immiscible alloys in space. The parameters obtained for this experiment are compared with those of liquid metals to determine if the same stability could be achieved with immiscible alloys.
Lacy, L. L.↗
Pressure-viscosity measurements for several lubricants to 550 meganewtons per square meter /80,000 PSI/ and 149 C /300 F/
The viscosities of a number of liquid lubricants and lubricant formulations, determined as function of pressure, temperature, and shear stress by means of a high-pressure capillary viscometer, are reviewed. Where possible, these results are compared with those obtained by other techniques (optical elastohydrodynamics, oscillating crystal, and low shear capillary viscometry).
Jones, W. R., Jr.↗