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  • INSTRUMENTATION AND PHOTOGRAPHY
  • 1980-1984  (258)
  • 1975-1979
  • 1965-1969
  • 1945-1949
  • 1983  (258)
Collection
Keywords
Years
  • 1980-1984  (258)
  • 1975-1979
  • 1965-1969
  • 1945-1949
Year
  • 101
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    Spas color camera (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The procedures to be followed in assessing the performance of the MOS color camera are defined. Aspects considered include: horizontal and vertical resolution; value of the video signal; gray scale rendition; environmental (vibration and temperature) tests; signal to noise ratios; and white balance correction.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-171739 , NAS 1.26:171739 , ED-AX-316
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  • 102
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    Digital multishaker modal testing (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A review of several modal testing techniques is made, along with brief discussions of their advantages and limitations. A new technique is presented which overcomes many of the previous limitations. Several simulated experiments are included to verify the validity and accuracy of the new method. Conclusions are drawn from the simulation studies and recommendations for further work are presented. The complete computer code configured for the simulation study is presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-170951 , NAS 1.26:170951 , CAR-83-1
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  • 103
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    Self-correcting electronically scanned pressure sensor (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A multiple channel high data rate pressure sensing device is disclosed for use in wind tunnels, spacecraft, airborne, process control, automotive, etc., pressure measurements. Data rates in excess of 100,000 measurements per second are offered with inaccuracies from temperature shifts less than 0.25% (nominal) of full scale over a temperature span of 55 C. The device consists of thirty-two solid state sensors, signal multiplexing electronics to electronically address each sensor, and digital electronic circuitry to automatically correct the inherent thermal shift errors of the pressure sensors and their associated electronics.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 104
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    Ride quality meter (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A ride quality meter is disclosed that automatically transforms vibration and noise measurements into a single number index of passenger discomfort. The noise measurements are converted into a noise discomfort value. The vibrations are converted into single axis discomfort values which are then converted into a combined axis discomfort value. The combined axis discomfort value is corrected for time duration and then summed with the noise discomfort value to obtain a total discomfort value.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 105
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    Low energy electron magnetometer using a monoenergetic electron beam (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A low energy electron beam magnetometer utilizes near-monoenergetic electrons thereby reducing errors due to electron energy spread and electron nonuniform angular distribution. In a first embodiment, atoms in an atomic beam of an inert gas are excited to a Rydberg state and then electrons of near zero energy are detached from the Rydberg atoms. The near zero energy electrons are then accelerated by an electric field V(acc) to form the electron beam. In a second embodiment, a filament emits electrons into an electrostatic analyzer which selects electrons at a predetermined energy level within a very narrow range. These selected electrons make up the electron beam that is subjected to the magnetic field being measured.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 106
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    Inflatable device for installing strain gage bridges (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Methods and devices for installing in a tubular shaft multiple strain gages are disclosed with focus on a method and a device for pneumatically forcing strain gages into seated engagement with the internal surfaces of a tubular shaft in an installation of multiple strain gages in a tubular shaft. The strain gages or other electron devices are seated in a template-like component which is wrapped about a pneumatically expansible body. The component is inserted into a shaft and the body is pneumatically expanded after a suitable adhesive was applied to the surfaces.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 107
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    Proposed fast-response oxygen monitoring and control system for the Langley 8-foot high-temperature tunnel (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A fast-response oxygen monitoring and control system, based on a Y2O3-stabilized ZrO2 sensor, was developed and tested in the laboratory. The system is capable of maintaining oxygen concentration in the CH4-O2-air combustion product gases at 20.9 + or - 1.0 percent. If the oxygen concentration in the exhaust stream differs from that in normal air by 25 percent or more, an alarm signal is provided for automatic tunnel shutdown. The overall prototype system response time was reduced from about 1 sec in the original configuration to about 0.2 sec. The basis of operation and the results of laboratory tests of the system are described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TP-2218 , L-15666 , NAS 1.60:2218
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  • 108
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    A technique for dynamically calibrating pressure transducers at cryogenic temperatures (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A technique was developed for the calibration of dynamic pressure transducers at cryogenic temperatures. The calibration system utilizes an 8.9 Newton peak thrust shaker which oscillates a helium-filled bellows to generate a sinusoidal dynamic pressure to calibrate transducers immersed in a cryogenic environment. The system has a dynamic pressure measurement uncertainty of approximately 11% and is capable of producing peak-to-peak dynamic pressure amplitudes of 1.4 kPa over a frequency range of 40 to 100 hertz and a temperature range of 100 to 300 K. It provides an unprecedented capability of both static and dynamic calibration of pressure transducers from ambient to cryogenic temperature.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-85695 , NAS 1.15:85695
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  • 109
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    Video model deformation system for the National Transonic Facility (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A photogrammetric closed circuit television system to measure model deformation at the National Transonic Facility is described. The photogrammetric approach was chosen because of its inherent rapid data recording of the entire object field. Video cameras are used to acquire data instead of film cameras due to the inaccessibility of cameras which must be housed within the cryogenic, high pressure plenum of this facility. A rudimentary theory section is followed by a description of the video-based system and control measures required to protect cameras from the hostile environment. Preliminary results obtained with the same camera placement as planned for NTF are presented and plans for facility testing with a specially designed test wing are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NAS 1.15:85681 , NASA-TM-85681 , Ann. Meeting of the Virginia Acad. of Sci.; VA; United States
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  • 110
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    Laser diagnostic methods - A summary (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: This is a summary and discussion of the state of the art in the use of laser diagnostics in fluid and plasma dynamics. This will encompass: interferometry, scattering, spectroscopy, and velocimetry. Examples of such applications will be provided in the area of fluid dynamics of particle generation and breakup, analysis of three-dimensional density fields, and applications in combustion.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 83-1683
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  • 111
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    A miniature, directional surface-fence gage for three-dimensional turbulent boundary layer measurements (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A new miniature (3.175 mm overall diameter) surface-fence gage was developed to measure simultaneously the magnitude and direction of wall shear stress under three-dimensional turbulent boundary layers. Two fence elements were placed orthogonal to each other on the end surface of the gage. The gage was calibrated for its directional and magnitude sensitivities. It was then tested under an axisymmetric swirling boundary layer, subject to a sudden transverse strain. The advantage of the gage was demonstrated, and excellent agreement was obtained with the results from surface oil flow interferometry and velocity field measurements. The results also compared well with numerical computations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 83-1722
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  • 112
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    Simultaneous observation of rotational coherent Stokes Raman scattering and coherent anti-Stokes Raman scattering in air and nitrogen (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Rotational coherent Stokes Raman scattering (CSRS) and coherent anti-Stokes Raman scattering (CARS) in air and in nitrogen were observed simultaneously by using broadband generation and detection. In the broadband technique used, the entire CARS and CSRS spectrum was generated in a single laser pulse; the CSRS and CARS signals were dispersed by a spectrograph and detected simultaneously by an optical multichannel analyzer. A three-dimensional phase-matching geometry was used to achieve spatial resolution of the CSRS and CARS beams from the input beams. Under resonant conditions, similar experiments may provide a means of investigating the possible interaction between the CSRS and CARS processes in driving the rotational levels.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optics Letters (ISSN 0146-9592); 8; July 198
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  • 113
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    Laser microspeckle technique in displacement measurement near a crack tip (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The laser speckle method has been found quite useful in obtaining in-plane displacement measurements. It is especially useful if the displacement field in a small region can be effectively determined. By obtaining directly the speckle patterns at higher magnifications, a better distinction of the displacements in the vicinity of a crack tip is possible. In this short report some results are obtained and compared with those calculated from linear fracture mechanics and the finite element method for an aluminum crack.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Physics; 54; Apr. 198
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  • 114
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    Evaluation of a virtual phase charged-coupled device as an imaging X-ray spectrometer (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The X-ray response of an 800 x 800 Texas Instruments virtual phase charge-coupled device (CCD) has been measured in the range 1-8 keV. In the single-photon counting mode, excellent energy resolution (approximately 250 eV FWHM is found for single-pixel Fe-55 X-ray events at a spatial resolution of 15 microns. The detector quantum efficiency for all events is 65% at 2.3 keV (S K line) and approximately 34% at 5.9 keV (Mn K line from Fe-55). The CCD response is linear in energy to a few percent over the 1-8 keV energy range. These results demonstrate that virtual phase CCDs are superior imaging X-ray spectrometers with applications for X-ray astronomy and laboratory plasma research.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 54; Feb. 198
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  • 115
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    Thin film strain gage development program (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Sputtered thin-film dynamic strain gages of 2 millimeter (0.08 in) gage length and 10 micrometer (0.0004 in) thickness were fabricated on turbojet engine blades and tested in a simulated compressor environment. Four designs were developed, two for service to 600 K (600 F) and two for service to 900 K (1200 F). The program included a detailed study of guidelines for formulating strain-gage alloys to achieve superior dynamic and static gage performance. The tests included gage factor, fatigue, temperature cycling, spin to 100,000 G, and erosion. Since the installations are 30 times thinner than conventional wire strain gage installations, and any alteration of the aerodynamic, thermal, or structural performance of the blade is correspondingly reduced, dynamic strain measurement accuracy higher than that attained with conventional gages is expected. The low profile and good adherence of the thin film elements is expected to result in improved durability over conventional gage elements in engine tests.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-174707 , NAS 1.26:174707 , PWA-5628-69
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  • 116
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    Apparatus for continuous, fast, and precise measurements of position and velocity of a small spherical particle (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The position and velocity of optically levitated glass spheres (radii 10-20 microns) movng in a gas are measured accurately, rapidly, and continuously using a high-speed rotating polygon mirror. The experimental technique developed here has repeatable position accuracies better than 20 microns. Each measurement takes less than 1 microsec and can be repeated every 100 microsec. The position of the levitated glass spheres can be manipulated accurately by modulating the laser power with an acoustic optic modulator. The technique provides a fast and accurate method to study general particle dynamics in a fluid.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 54; 1643-164
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  • 117
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    Accuracy of relative positioning by interferometry with GPS Double-blind test results (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: MITES (Miniature Interferometer Terminals for Earth Surveying) observations conducted on December 17 and 29, 1980, are analyzed. It is noted that the time span of the observations used on each day was 78 minutes, during which five satellites were always above 20 deg elevation. The observations are analyzed to determine the intersite position vectors by means of the algorithm described by Couselman and Gourevitch (1981). The average of the MITES results from the two days is presented. The rms differences between the two determinations of the components of the three vectors, which were about 65, 92, and 124 m long, were 8 mm for the north, 3 mm for the east, and 6 mm for the vertical. It is concluded that, at least for short distances, relative positioning by interferometry with GPS can be done reliably with subcentimeter accuracy.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 118
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    X-ray spectrographs using radial groove gratings (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A high efficiency spectrograph design for the EUV and soft X rays is presented. This grazing incidence system uses a plane surface reflection grating with rulings that are radial, like the spokes of a wheel. The grating is placed in a beam of light that is converging to a focus. The single reflection off the grating is in the conical diffraction mount ensuring maximum performance from the system. Aberrations and performance levels are discussed. The gratings can be manufactured with existing ruling engines. Sample applications to an X-ray monochromator and an EUV stellar spectrograph are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 22; 3971-397
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  • 119
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    Dynamic gas temperature measurement system, volume 1 (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A gas temperature measurement system with compensated frequency response of 1 kHz and capability to operate in the exhaust of a gas turbine engine combustor was developed. A review of available technologies which could attain this objective was done. The most promising method was identified as a two wire thermocouple, with a compensation method based on the responses of the two different diameter thermocouples to the fluctuating gas temperature field. In a detailed design of the probe, transient conduction effects were identified as significant. A compensation scheme was derived to include the effects of gas convection and wire conduction. The two wire thermocouple concept was tested in a laboratory burner exhaust to temperatures of about 3000 F and in a gas turbine engine to combustor exhaust temperatures of about 2400 F. Uncompensated and compensated waveforms and compensation spectra are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-168267-VOL-1 , NAS 1.26:168267-VOL-1 , PWA/GPD-FR-17145-VOL-1
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  • 120
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    Techniques for avoiding discrimination errors in the dynamic sampling of condensable vapors (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: In the mass spectrometric sampling of dynamic systems, measurements of the relative concentrations of condensable and noncondensable vapors can be significantly distorted if some subtle, but important, instrumental factors are overlooked. Even with in situ measurements, the condensables are readily lost to the container walls, and the noncondensables can persist within the vacuum chamber and yield a disproportionately high output signal. Where single pulses of vapor are sampled this source of error is avoided by gating either the mass spectrometer ""on'' or the data acquisition instrumentation ""on'' only during the very brief time-window when the initial vapor cloud emanating directly from the vapor source passes through the ionizer. Instrumentation for these techniques is detailed and its effectiveness is demonstrated by comparing gated and nongated spectra obtained from the pulsed-laser vaporization of several materials.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-85886 , A-9511 , NAS 1.15:85886
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  • 121
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    A helium-3 cooled bolometer system for one millimeter continuum observations (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A new, 1-mm-continuum, bolometer detector system has been constructed employing internal adsorption pumping of He-3 to reach an operating temperature close to 0.4 K. The system spectral bandwidth is 800 to 1200 microns. Although the system was originally designed to be used on the 5-m Hale telescope, it has also been successfully used on the 4-m Anglo-Australian telescope and on the 10-m dish at Owens Valley, California. At the 5-m Hale telescope, the system has a full width-half maximum (FWHM) beam size of 55 sec and an instantaneous noise-equivalent flux density of 6 Jy/square root of (Hz)/ in good weather.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 4; May 1983
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  • 122
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    A sea surface height estimator using synthetic aperture radar complex imagery (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A method is developed for estimating the sea surface height using the complex imagery from synthetic aperture radar (SAR). Algorithms are developed for the envelope and phase demodulation, regression, and filtering of the SAR complex imagery and are applied to simulated and actual satellite radar SEASAT-SAR data. A simulation of a simplified stationary scene is utilized in order to establish tentative sufficient conditions on large-scale SAR and sampling parameters for the accurate estimation of the scale structure's height. It is shown that the algorithm accurately estimated a long wavelength low-amplitude sea height structure present in the SEASAT-SAR data, which was determined to be consistent with observations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Journal of Oceanic Engineering; OE-8; Apr. 198
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  • 123
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    High throughput non-dispersive hard X-ray spectrograph with angular resolution for cosmic bursts, transients, and sources (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An instrument concept which offers high throughput nondispersive spectroscopy in the 35-150 keV band for measuring line intensities and widths of faint supernovae is described. The design is based on existing xenon filled, two-dimensional, position sensitive, multiwired proportional counters. Effective detector areas of 1000 sq cm are readily achievable, and expansion to 10,000 sq cm per unit is feasible. Either single-unit or array operation to provide all-sky coverage with one arcmin resolution is possible. The instrument could be used to record gamma ray bursts and would have the capability of distinguishing particle events. Observations could also be made of X ray cyclotron lines and the Ti-44 lines expected to issue from a supernova explosion.
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  • 124
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    Gamma ray detection with long NaI/Tl/ scintillator bars (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Test measurements with a prototype NaI(Tl) scintillator for energy, position, and timing measurements in gamma ray astronomy are reported. The scintillator bar is 100 x 5 x 5 cu cm in size, and allows detection of the arrival times and pulse heights of signals from two photomultiplier tubes, one at each end of the bar. Data is gathered on the energy loss, linear position, and time-of-flight of gamma ray interactions within the bar over an energy range of 0.5-20 MeV. A mean attenuation coefficient of 0.015/cm has been determined, as have a FWHM resolution of 5 cm, 9.4%, and 10 nsec at an energy of 0.662 MeV. At 1.25 MeV the timing resolution was 6 nsec, and at 6.13 MeV the spatial resolution was 2.2 cm. The instrument is a prototype of a Compton scatter telescope being constructed for two balloon flights, one each in the Northern and Southern Hemispheres, in 1984.
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  • 125
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    Projection moire for remote contour analysis (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Remote projection and viewing of moire contours are examined analytically for a system employing separate projection and viewing optics, with specific attention paid to the practical limitations imposed by the optical systems. It is found that planar contours are possible only when the optics are telecentric (exit pupil at infinity) but that the requirement for spatial separability of the contour fringes from extraneous fringes is independent of the specific optics and is a function only of the angle separating the two optic axes. In the nontelecentric case, the contour separation near the object is unchanged from that of the telecentric case, although the contours are distorted into low-eccentricity (near-circular) ellipses. Furthermore, the minimum contour spacing is directly related to the depth of focus through the resolution of the optics.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Society of America; vol. 73
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  • 126
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    Coherent scattering of a spherical wave from an irregular surface (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The scattering of a spherical wave from a rough surface using the Kirchhoff approximation is considered. An expression representing the measured coherent scattering coefficient is derived. It is shown that the sphericity of the wavefront and the antenna pattern can become an important factor in the interpretation of ground-based measurements. The condition under which the coherent scattering-coefficient expression reduces to that corresponding to a plane wave incidence is given. The condition under which the result reduces to the standard image solution is also derived. In general, the consideration of antenna pattern and sphericity is unimportant unless the surface-height standard deviation is small, i.e., unless the coherent scattering component is significant. An application of the derived coherent backscattering coefficient together with the existing incoherent scattering coefficient to interpret measurements from concrete and asphalt surfaces is shown.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AD-A135765 , IEEE Transactions on Antennas and Propagation; AP-31; Jan. 198
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  • 127
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    Errors in scatterometer-radiometer wind measurement due to rain (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The behavior of radiometer corrections for the scatterometer is investigated by simulating simple situations using footprint sizes comparable with those used in the SEASAT-1 experiment and also actual footprints and rain rates from a hurricane observed by the SEASAT-1 system. The effects on correction due to attenuation and wind speed gradients are examined independently and jointly. It is shown that the error in the wind-speed estimate can be as large as 200% at higher wind speeds. The worst error occurs when the scatterometer footprint overlaps two or more radiometer footprints and the attenuation in the scatterometer footprint differs greatly from those in parts of the radiometer footprints. This problem could be overcome by using a true radiometer-scatterometer system having identical coincident footprints comparable in size with typical rain cells.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Journal of Oceanic Engineering; OE-8; Jan. 198
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  • 128
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    Numerical simulation of a disk-shaped electron accelerating electrostatic probe (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: This paper presents a method utilizing the numerical plasma simulation particle-in-cell technique for studying electron accelerating probe characteristics. A probe configuration other than the commonly used plane, cylindrical, or spherical case will be studied; the probe configuration used is that of a disk. Cylindrical geometry is used in the simulation model. One of the advantages of a numerical simulation is the ease with which the details of the system can be examined. Therefore, in addition to the current-voltage characteristics of the static probe, other results are presented such as the time evolution of the plasma properties and studies of the sheath region surrounding the probe.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Physics; 54; Feb. 198
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  • 129
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    Design and development of a fast ion mass spectrometer (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Two Fast Ion Mass Spectrometers (FIMS A and FIMS B) were developed. The design, development, construction, calibration, integration, and flight of these instruments, along with early results from the data analysis efforts are summarized. A medium energy ion mass spectrometer that covers mass velocity space with significantly higher time resolution, improved mass resolution, (particularly for heavier ions), and wider energy range than existing instruments had achieved was completed. The initial design consisted of a dual channel cylindrical electrostatic analyzer followed by a dual channel cylindrical velocity filter. The gain versus count rate characteristics of the high current channel electron multipliers (CEM's), which were chosen for ion detection, revealed a systematic behavior that can be used as a criterion for selection of CEM's for long counting lifetimes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-169988 , NAS 1.26:169988
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  • 130
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    Remote sensing of sediment and chlorophyll with the test-bed aircraft multispectral scanner (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An instrument known as the test-bed aircraft multispectral scanner (TBAMS) was used in a research flight over the entrance to the Chesapeake Bay. Upwelled radiances from the TBAMS data were correlated with the water parameters, particularly sediment and chlorophyll a. Several algorithms were demonstrated for monitoring sediment and chlorophyll, with a three-band ratio being the best. The primary advantage of the three-band ratio was found to be its apparent insensitivity to atmospheric and Sun-angle variations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-84590 , L-15572 , NAS 1.15:84590
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    The state-of-the-art of cryogenic thermometry and signal conditioners and their potential for standardized space hardware (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The possibility of standard low temperature detector(s) for use in upcoming cryogenically cooled satellite and Space Shuttle payloads were investigated. These payloads operate from .3 kelvin to 300 kelvin. Standard detectors were selected and matching signal conditioning equipment compatible with the selected detector, typical spacecraft voltages, typical spacecraft telemetry systems, and the radiation encountered by a typical Earth orbiting spacecraft. Work statements to better define and advance detector performance were presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-166451 , NAS 1.26:166451
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  • 132
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    A balloon-borne instrument for high-resolution astrophysical spectroscopy in the 20-8000 keV energy range (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Low Energy Gamma ray Spectrometer (LEGS) is designed to perform fine energy resolution measurements of astrophysical sources. The instrument is configured for a particular balloon flight with either of two sets of high purity germanium detectors. In one configuration, the instrument uses an array of three coaxial detectors (effective volume equal to or approximately 230 cubic cm) inside an NaI (T1) shield and collimator (field of view equal to or approximately 16 deg FWHM) and operates in the 80 to 8000 keV energy range. In the other configuration, three planar detectors (effective area equal to or approximately square cm) surrounded by a combination of passive Fe and active NaI for shielding and collimation (field of view equal to or approximately 5 deg x 10 deg FWHM) are optimized for the 20 to 200 keV energy range. In a typical one day balloon flight, LEGS sensitivity limit (3 sigma) for narrow line features is less than or approximately .0008 ph/cm/s square (coaxial array: 80 to 2000 keV) and less than or approximately .0003 ph/square cm/s (planar array: 50 to 150 keV).
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-85011 , NAS 1.15:85011
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  • 133
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    Nimbus-6 and -7 Earth Radiation Budget (ERB) sensor details and component tests (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Construction details and operating characteristics are described for the thermopile (used in the solar and fixed-Earth channels) and the pyroelectric detector (used in the Earth-scanning channels) carried on the Nimbus 6 and the Nimbus 7 satellites for gathering Earth radiation budget data. Properties of the black coating for the detectors, and sensor testing and calibration are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-83906 , NAS 1.15:83906 , G-82F2002
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  • 134
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    Halogen Occultation Experiment (HALOE) gas cell life test program (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Halogen Occultation Experiment (HALOE) will use gas filter correlation radiometry to measure the atmospheric concentration profiles of HCl, HF, NO, and CH4 from the Upper Atmosphere Research Satellite. The need to contain the gases for the gas filter measurements has resulted in the development of gas cells and the need for a life test program to demonstrate that the gas cells will perform their functions for extended periods (several years) of time. This report describes the tests in the life test program, the test apparatus used, and the analysis techniques developed. The report also presents data obtained during the first 14 months of the test program.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-84640 , L-15581 , NAS 1.15:84640
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  • 135
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    Vibration isolation and pressure compensation apparatus for sensitive instrumentation (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: A system for attenuating the inherent vibration associated with a mechanical refrigeration unit employed to cryogenically cool sensitive instruments used in measuring chemical constituents of the atmosphere is described. A modular system including an instrument housing and a reaction bracket with a refrigerator unit floated there between comprise the instrumentation system. A pair of evacuated bellows that "float' refrigerator unit and provide pressure compensation at all levels of pressure from seal level to the vacuum of space. Vibration isolators and when needed provide additional vibration damping for the refrigerator unit. A flexible thermal strap (20 K) serves to provide essentially vibration free thermal contact between cold tip of the refrigerator unit and the instrument component mounted on the IDL mount. Another flexible strap (77 K) serves to provide vibration free thermal contact between the TDL mount thermal shroud and a thermal shroud disposed about the thermal shaft.
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  • 136
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    Instrumental effects on the temperature and density derived from the light ion mass spectrometer (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An expression for the flux into a retarding potential analyzer (RPA) is derived which takes into account the instrumental effect of a dependence on energy of the solid angle of the acceptance cone. A second instrumental effect of a limited bandpass is briefly discussed. Using the (LIMS) instrument on SCATHA, it is shown that temperatures and densities derived without considering the effect of the solid angle dependence on energy will be too low, dramatically so for E(t) E(1), where E(1) is the e folding distance of the solid angle dependence and E(t) is the thermal energy of the plasma. For E(t) E(1), there is effectively no impact on the derived temperatures and densities if the solid angle effect is ignored.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-82536 , NAS 1.15:82536
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  • 137
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    The development of a power spectral density processor for C and L band airborne radar scatterometer sensor systems (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: A real-time signal processor was developed for the NASA/JSC L-and C-band airborne radar scatterometer sensor systems. The purpose of the effort was to reduce ground data processing costs. Conversion of two quadrature channels of data (like and cross polarized) was made to obtain Power Spectral Density (PSD) values. A chirp-z transform (CZT) approach was used to filter the Doppler return signal and improved high frequency and angular resolution was realized. The processors have been tested with record signals and excellent results were obtained. CZT filtering can be readily applied to scatterometers operating at other wavelengths by altering the sample frequency. The design of the hardware and software and the results of the performance tests are described in detail.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-171668 , NAS 1.26:171668 , LEMSCO-19158
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  • 138
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    Handbook on COMTAL's Image Processing System (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: An image processing system is the combination of an image processor with other control and display devices plus the necessary software needed to produce an interactive capability to analyze and enhance image data. Such an image processing system installed at NASA Langley Research Center, Instrument Research Division, Acoustics and Vibration Instrumentation Section (AVIS) is described. Although much of the information contained herein can be found in the other references, it is hoped that this single handbook will give the user better access, in concise form, to pertinent information and usage of the image processing system.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-85671 , NAS 1.15:85671
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  • 139
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    Degassifying and mixing apparatus for liquids (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: An apparatus for degassing a liquid comprises a containment vessel a liquid pump and a header assembly (12) within the containment vessel in a volume above the reservoir of the liquid. The pump draws from this reservoir and outputs to the header assembly, the latter being constructed to return the liquid to the reservoir in the form of a number of stacked, vertically spaced, concentric, conical cascades via orifices. A vacuum source provides a partial vacuum in the containment vessel to enhance the degassing process.
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  • 140
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    Instrument for determining coincidence and elapse time between independent sources of random sequential events (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An instrument that receives pulses from a primary external source and one or more secondary external sources and determines when there is coincidence between the primary and one of the secondary sources is described. The instrument generates a finite time window (coincidence aperture) during which coincidence is defined to have occurred. The time intervals between coincidence apertures in which coincidences occur are measured.
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  • 141
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    Method and apparatus for supercooling and solidifying substances (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: An enclosure provides a containerless environment in which a sample specimen is positioned. The specimen is heated in the containerless environment, and the specimen melt is dropped through the tube in which it cools by radiation. The tube is alternatively backfilled with an inert gas whereby the specimen melt cools by both radiation and convection during its free fall. During the free fall, the sample is in a containerless, low-gravity environment which enhances supercooling in the sample and prevents sedimentation and thermal convection influences. The sample continues to supercool until nucleation occurs which is detected by silicon photovoltaic detectors. The sample solidifies after nucleation and becomes completely solid before entering the detachable catcher. The amount of supercooling of the specimen can be measured by knowing the cooling ratio and determining the time for nucleation to occur.
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  • 142
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    Bench cooling the Thematic Mapper (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The present investigation is concerned with the bench cooling system which was developed in conjunction with the Thematic Mapper (TM), a second-generation earth resources sensor. A small, permanently evacuated dewar, which is carried into space with the instrument, is employed to provide thermal isolation for bench cooling IR detectors of many space-borne instruments. This approach has, however, a number of disadvantages. The system designed for cooling the TM makes, therefore, use of a new approach, involving a temporarily evacuated, take-apart dewar in combination with a temperature-controlled Joule-Thomson cryostat.
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  • 143
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    In-flight radiometric calibration of advanced remote sensing systems (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Several methods for the in-flight calibration of advanced remote sensing systems are reviewed. Pre-flight and in-flight detector-based calibration are discussed. Calibration by reference to instrumented ground targets is suggested for current systems. Preliminary data are presented on the accuracy and sensitivity required of measurements of ground targets and the atmosphere between the targets and the sensor to achieve an uncertainty in absolute terms of less than + or - 3 percent in the calibration of Landsat-4 systems.
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  • 144
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    Exact modeling of lineshape and wavenumber variations for off-axis detectors in Fourier transform spectrometers (FTS) sensor systems (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The utilization of detector arrays in the focal planes of FTS sensor systems allows simultaneous spectral and spatial measurements. However, spectral lineshapes and wavenumber locations depend upon the size and location of the detector elements with respect to the Haidinger fringe pattern of the FTS sensor. These spectral distortions can be generalized as a shift and shape change of the FTS sensor lineshape. Depending on the distortions that can be tolerated, a degree of field-widening can be obtained for a given Haidinger fringe pattern. An exact model for predicting the FTS lineshape distortions is presented. The model is applied to several contemporary applications in order to quantify the magnitude of distortions to be expected.
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  • 145
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    Radiometer requirements for Earth-observation systems using large space antennas (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Requirements are defined for Earth observation microwave radiometry for the decade of the 1990's by using large space antenna (LSA) systems with apertures in the range from 50 to 200 m. General Earth observation needs, specific measurement requirements, orbit mission guidelines and constraints, and general radiometer requirements are defined. General Earth observation needs are derived from NASA's basic space science program. Specific measurands include soil moisture, sea surface temperature, salinity, water roughness, ice boundaries, and water pollutants. Measurements are required with spatial resolution from 10 to 1 km and with temporal resolution from 3 days to 1 day. The primary orbit altitude and inclination ranges are 450 to 2200 km and 60 to 98 deg, respectively. Contiguous large scale coverage of several land and ocean areas over the globe dictates large (several hundred kilometers) swaths. Radiometer measurements are made in the bandwidth range from 1 to 37 GHz, preferably with dual polarization radiometers with a minimum of 90 percent beam efficiency. Reflector surface, root mean square deviation tolerances are in the wavelength range from 1/30 to 1/100.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-RP-1101 , L-15429 , NAS 1.61:1101
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  • 146
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    Experimental study using Nearfield Acoustical Holography of sound transmission fuselage sidewall structures (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: This project involves the development of the Nearfield Acoustic Holography (NAH) technique (in particular its extension from single frequency to wideband noise measurement) and its application in a detailed study of the noise radiation characteristics of several samples of aircraft sidewall panels. With the extensive amount of information provided by the NAH technique, the properties of the sound field radiated by the panels may be correlated with their structure, mounting, and excitation (single frequency or wideband, spatially correlated or uncorrelated, structure-borne). The work accomplished at the beginning of this grant period included: (1) Calibration of the 256 microphone array and test of its accuracy. (2) extension of the facility to permit measurements on wideband noise sources. The extensions incuded the addition of high-speed data acquisition hardware and an array processor, and the development of new software. (3) Installation of motion picture graphics for correlating panel motion with structure, mounting, radiation, etc. (4) Development of new holographic data processing techniques.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-173639 , NAS 1.26:173639
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  • 147
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    NSI-1 Squib adapter development and final test report for usage on space shuttle gas sampler valve/bottle assembly 3270 (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The possibility of utilizing the NSI-1 squib in place cartridge assembly 2270 for the function of both events required for the Space Shuttle Gas Sampler Valve/Bottle Assembly 3270 was determined. Additionally, it was a requirement that the closure disk of the NSI-1 squib and explosive residue therefrom be retained from the valve cavity in so far as possible to prevent any significant particulate from scratching the valve bore and causing sample leakage following the postfire 2 event.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-171735 , NAS 1.26:171735 , ER-2273-8
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  • 148
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    Resolution of vertical mixing-ratio profiles of atmospheric constituents retrieved from solar spectra (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The relationship between the uncertainty and the resolution of the mixing-ratio profiles of absorbing gases retrieved from simulated occultation data has been investigated by analyzing sets of absorber amounts, corresponding to a constituent with a constant vertical mixing-ratio profile, along atmospheric paths observed by instruments at 0, 30, and 500 km. The vertical resolution below the instrument is limited by the number of observations and the SNR; it degrades exponentially with height and is independent of the instrument altitude; it is nearly 50 times better than the resolution obtainable above the instrument. An estimate of the resolution obtained by analyzing line shapes is included for comparison.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 22; Oct. 1
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  • 149
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    Proposal for the measuring molecular velocity vector with single-pulse coherent Raman spectroscopy (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Methods for simultaneous measurements of more than one flow velocity component using coherent Raman spectroscopy are proposed. It is demonstrated that using a kilowatt broad-band probe pulse (3-30 GHz) along with a megawatt narrow-band pump pulse (approximately 100 MHz), coherent Raman signal resulting from a single laser pulse is sufficient to produce a high-resolution Raman spectrum for a velocity measurement.
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    Type: Applied Physics B - Photophysics and Laser Chemistry (ISSN 0721-7269); B 32; Sept
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  • 150
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    An extensometer for axial strain measurement at high temperature (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Most existing strain measuring instruments, important for the investigation of the mechanical behavior of metals at high temperature, have temperature, strain range, and size limitations. In this short note the authors give the design and construction of an extensometer with sufficient dynamic range and good stability over long periods of time, for measuring the longitudinal strain of plane specimens from 0.001 to 0.1 at temperatures up to 800 C.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Mechanics of Materials (ISSN 0167-6636); 2; Aug. 198
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  • 151
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    Effects of photon noise on speckle image reconstruction with the Knox-Thompson algorithm (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: An analysis of the effects of photon noise on astronomical speckle image reconstruction using the Knox-Thompson algorithm is presented. It is shown that the quantities resulting from the speckle average arre biased, but that the biases are easily estimated and compensated. Calculations are also made of the convergence rate for the speckle average as a function of the source brightness. An illustration of the effects of photon noise on the image recovery process is included.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optics Communications (ISSN 0030-4018); 47; Aug. 15
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  • 152
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    Particle-sampling statistics in laser anemometers Sample-and-hold systems and saturable systems (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The effect of the data-processing system on the particle statistics obtained with laser anemometry of flows containing suspended particles is examined. Attention is given to the sample and hold processor, a pseudo-analog device which retains the last measurement until a new measurement is made, followed by time-averaging of the data. The second system considered features a dead time, i.e., a saturable system with a significant reset time with storage in a data buffer. It is noted that the saturable system operates independent of the particle arrival rate. The probabilities of a particle arrival in a given time period are calculated for both processing systems. It is shown that the system outputs are dependent on the mean particle flow rate, the flow correlation time, and the flow statistics, indicating that the particle density affects both systems. The results are significant for instances of good correlation between the particle density and velocity, such as occurs near the edge of a jet.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 133; Aug. 198
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  • 153
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    The High Spectral Resolution Lidar (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The High Spectral Resolution Lidar (HSRL) system was developed for the remote measurement of atmospheric optical properties. Measurements are obtained by the separation of the backscattered signal into aerosol and molecular channels using a high spectral resolution Fabry-Perot optical interferometer to separate the aerosol contributions to backscatter near the laser wavelength from the Doppler-shifted molecular component of the backscatter. The transmitter consists of an optically pumped pulsed dye laser of the oscillator-amplifier design which emits at 467.88 nm, with a bandwidth of less than 0.3 pm. The transmitter and receiver share a common Schmidt-Cassegrain telescope, although they do not share the same field stop, but rather two conjugate stops. The HSRL system uses a computer-controlled dual-channel photon-counting data acquisition system providing for stable measurements at very low power levels and an excellent dynamic range. The system has been used to obtain airborne measurements of height profiles of aerosol and molecular backscatter cross sections.
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  • 154
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    High-resolution lidar system for measuring the spatial and temporal structure of the mesospheric sodium layer (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The design of a high-resolution tunable-dye laser-based lidar system for the study of the mesospheric sodium layer is presented and results of sodium measurements are indicated. The lidar system comprises a tunable flashlamp-pumped dye laser operating at the sodium D2 resonance line at 589.0 nm with a pulse width of 2 microsec FWHM and pulse frequency of 10 Hz and a telescope with a 1.22=m diameter Fresnel lens. Sodium profiles are obtained from the integration of 100 to 250 laser shots, with spatial and temporal resolution enhanced by two-dimensional filtering techniques. Measurements obtained over a 9-hour nighttime period illustrate the highly dynamic nature of the sodium layer, which was observed with a spatial resolution of 2 km and temporal resolution of 30 min. Observations made with a steerable apparatus have confirmed a presunrise enhancement of over 100 percent in sodium column abundance.
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  • 155
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    Tunable laser heterodyne spectrometer measurements of atmospheric species (1983)
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    Publication Date: 2019-06-28
    Description: It is pointed out that spectroscopic measurements conducted with the aid of tunable laser heterodyne spectrometers in the 3-30 micron range of the electromagnetic spectrum have the potential to measure the vertical profiles of tenuous gas molecules in the atmosphere with ultra high spectral resolution and great sensitivity. Programs related to the realization of this potential have been conducted for some time, and a Laser Heterodyne Spectrometer (LHS) experiment was developed. The present investigation has the objective to provide an overview of the LHS concept for measuring the vertical profiles of tenuous gas molecules in the upper atmosphere from space and airborne platforms, and to discuss the sensitivity ranges for this technique.
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  • 156
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    Remote measurement of trace gases with the JPL laser absorption spectrometer (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Extensive data from large regions are needed as a basis for the study of anthropogenic trace gases in the troposphere. The need arises, therefore, for an instrument which is capable to monitor rapidly the atmosphere in a region. The present investigation is concerned with the results of efforts to develop an instrument which is capable of remotely measuring gases in the troposphere. The Laser Absorption Spectrometer (LAS) was designed for use in aircraft, and was employed to measure tropospheric ozone distribution since 1977. Attention is given to a description of the LAS instrument, the theoretical basis of instrument operation, LAS measurement programs, the results of the LAS development program, and future work.
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  • 157
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    The Mount Wilson magnetograph (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: In the summer of 1957, an instrument quite similar to the prototype solar magnetograph described by Babcock (1953) was installed at the 150-foot tower telescope at the Mount Wilson Observatory, and daily magnetograph observations of the full disk of the sun were started. During the following years, the instrument was modified and improved on several occasions. The present investigation is concerned with the present state of the magnetograph, which was largely rebuilt during 1981. Attention is given to the spectrograph entrance slit, the diffraction grating, the exit slit, the employed microprocessor, the setup procedure, the magnetic signal, the Doppler signal, and a solar magnetogram.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Solar Physics (ISSN 0038-0938); 87; Aug. 198
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  • 158
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    Laser-induced fluorescence spectroscopy for combustion diagnostics (1983)
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    Publication Date: 2019-06-28
    Description: The types of spectroscopic and collisional measurements that are needed to develop laser-induced fluorescence as a diagnostic technique are discussed, with emphasis placed on combustion measurements. The spectroscopic measurements under collision-free conditions include production of radicals, excitation scan studies, lifetime measurements, and fluorescence scans. The collisional studies discussed here are quenching, energy transfer, and polarization phenomena. The results of recent laboratory experiments are presented.
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    Type: AD-A135307 , Optical Engineering (ISSN 0091-3286); 22; Sept
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  • 159
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    Improved fabrication techniques for infrared bolometers (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Ion implantation and sputter metallization are used to produce ohmic electrical contacts to Ge:Ga chips. The method is shown to give a high yield of small monolithic bolometers with very little low-frequency noise. It is noted that when one of the chips is used as the thermometric element of a composite bolometer it must be bonded to a dielectric substrate. The thermal resistance of the conventional epoxy bond is measured and found to be undesirably large. A procedure for soldering the chip to a metallized portion of the substrate in such a way as to reduce this resistance is outlined. An evaluation is made of the contribution of the metal film absorber to the heat capacity of a composite bolometer. It is found that the heat capacity of a NiCr absorber at 1.3 K can dominate the bolometer performance. A Bi absorber possesses significantly lower heat capacity. A low-temperature blackbody calibrator is built to measure the optical responsivity of bolometers. A composite bolometer system with a throughput of approximately 0.1 sr sq cm is constructed using the new techniques. The noise in this bolometer is white above 2.5 Hz and is slightly below the value predicted by thermodynamic equilibrium theory.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 4; Sept
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    Comparison of several techniques to obtain multiple-look SAR imagery (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: In order to improve image interpretability when SAR imagery is contaminated by coherent speckle noise, multiple look images are often generated. The performance levels of techniques for the generation of such multiple look imagery are presently assessed, with attention to the detailed impulse responses and signal-to-speckle noise ratios obtainable. The speckle-reduction technique considered are those of the discrete mixed integrator and the image domain filter. It is found that, by using several types of image domain filters, the signal-to-speckle noise ratio can be improved over the conventional discrete mixed integrator method's results while maintaining the equivalent rectangular resolution constant.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: (ISSN 0196-2892)
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  • 161
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    Laser-induced fluorescence technique for velocity field measurements in subsonic gas flows (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A nonintrusive optical technique is reported for multiple-point velocity measurements in subsonic flows. The technique is based on the detection of fluorescence from a Doppler-shifted absorption line of seeded iodine molecules excited at a laser frequency fixed in the wing of the line. Counterpropagating laser sheets are used to illuminate the flow, in the present case a nitrogen round jet, thereby eliminating the need for an unshifted reference signal. The fluorescence is detected simultaneously at 10,000 points in a plane of the flow using a 100 x 100 element photodiode-array camera. The velocity at each point is computed from four successive camera frames, each recorded with a different beam direction. The measured mean velocities between 5 and 50 m/sec agree well with data from the literature.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optics Letters (ISSN 0146-9592); 8; Sept
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  • 162
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    Aircraft-borne lightning sensor (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: An instrument is described that has been used to measure the spatial and temporal distributions of lightning strokes as seen from a high-altitude aircraft platform. It consists of two separate sensors. One has a lens, selectable filters, and a 50 x 50 element array of photodiodes. The second has an identical lens, filters, and a single detector that covers the same total field of view.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering (ISSN 0091-3286); 22; July-Aug
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  • 163
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    Calibration of long wavelength Exotech model 20C spectroradiometer (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Rockwell Associates, Inc. Opt. Radiation Detectors and Devices, Pt. 1; p 141-148
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  • 164
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    Mosaic Infrared Sensor for Space Astronomy (MIRSSA) (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: The development of mosaic infrared detector/focal plane arrays for space astronomy is reported. The Mosaic IR Sensor for Space Astronomy (MIRSSA) Program is an effort to develop PV HgCdTe detector arrays with the spectral response of up to 5 micron and silicon CCDs for low temperature applications. Desired background-limited performance (BLIP) for space applications requires an extremely high R sub A product which can be achieved by selecting the detector materials and the operating temperature. The parameters were determined by measurement of HgCdTe PV detector arrays at various temperatures in the SW and MW spectral bands. It is demonstrated that high performance PV HgCdTe detectors can be fabricated for low temperature applications.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-176154 , NAS 1.26:176154 , H-8407-07
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  • 165
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    An imaging gas scintillation proportional counter for use in X-ray astronomy (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: An imaging gas scintillation proportional counter (GSPC) has been constructed for use in X-ray astronomy. The IGSPC consists of a gas scintillation proportional counter (GSPC) with a 1 micron polypropylene window coupled to a multiwire proportional counter (MWPC) via a calcium fluoride window. The MWPC, filled with a mixture of argon, methane, and tetrakis (dimethylamino) ethylene, detects the UV photons emitted by the xenon gas in the GSPC. The measured energy resolution is 17.0 percent (fwhm) and 8.0 percent (fwhm) at 1.5 keV and 5.9 keV, respectively. The measured position resolution is 1.9 mm (fwhm) and 0.9 mm (fwhm) at 1.5 and 5.9 keV, respectively. Possible astrophysical observations which can be performed with an IGSPC at the focal plane of a grazing incidence telescope are also discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nuclear Instruments and Methods (ISSN 0167-5087); 213; 397-410
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  • 166
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    Tape/head interface study (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: Existing high energy tapes, high track density heads, and transport guidance techniques were evaluated and characterized to enable these technologies to be employed in future spacecraft recorders with high confidence. The results of these study efforts demonstrated tracking accuracy tape and head density that will support spacecraft recorders with data rates of a minimum of 150 Mbps and storage capacities ranging from 10 to the 10th to 10 to the 11th bits. Seven high energy tapes of either .25 in width, 1.00 in width, or both, were tested. All tapes were tested at the same speed (30 ips) and the same packing density (33 KBI). The performance of all 1 in tapes was considered superior.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-170594 , NAS 1.26:170594
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  • 167
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    High density tape/head interface study (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: The high energy (H sub c approximately or = to 650 oersteds) tapes and high track density (84 tracks per inch) heads investigated had, as its goal, the definition of optimum combinations of head and tape, including the control required of their interfacial dynamics that would enable the manufacture of high rate (150 Mbps) digital tape recorders for unattended space flight.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-170592 , NAS 1.26:170592 , O-911010
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  • 168
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    Performance of an airborne imaging 92/183 GHz radiometer during the Bering Sea Marginal Ice Zone Experiment (MIZEX-WEST) (1983)
    In:  Other Sources
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    Publication Date: 2019-07-27
    Description: An airborne imaging 92/183 GHz radiometer was recently flown onboard NASA's Convair 990 research aircraft during the February 1983 Bering Sea Marginal Ice Zone Experiment (MIZEX-WEST). The 92 GHz portion of the radiometer was used to gather ice signature data and to generate real-time millimeter wave images of the marginal ice zone. Dry atmospheric conditions in the Arctic resulted in good surface ice signature data for the 183 GHz double sideband (DSB) channel situated + or - 8.75 GHz away from the water vapor absorption line. The radiometer's beam scanner imaged the marginal ice zone over a + or - 45 degrees swath angle about the aircraft nadir position. The aircraft altitude was 30,000 feet (9.20 km) maximum and 3,000 feet (0.92 km) minimum during the various data runs. Calculations of the minimum detectable target (ice) size for the radiometer as a function of aircraft altitude were performed. In addition, the change in the atmospheric attenuation at 92 GHz under varying weather conditions was incorporated into the target size calculations. A radiometric image of surface ice at 92 GHz in the marginal ice zone is included.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Millimeter wave technology II; August 23, 24, 1983; San Diego, CA
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  • 169
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    Monolithic lead salt-silicon focal plane development (1983)
    In:  Other Sources
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    Publication Date: 2019-07-27
    Description: This paper is a summary of work done in the development of monolithic lead salt-silicon infrared focal plane technology. The photoconductive detector materials, PbS and PbSe are chemically deposited onto premetallized silicon MOSFET integrated circuit wafers. A variety of structures based on an implanted PMOS process were fabricated and evaluated. Operational results of an eight-element PbS array multiplexed on-chip are presented along with radiometric measurements on other integrated PbS-silicon MOSFET structures. PbS imagery is shown using one element of a 20-element array integrated on-chip.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Technical issues in infrared detectors and arrays; April 5, 6, 1983; Arlington, VA
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  • 170
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    A tunable coherent CO2 lidar for measurements of atmospheric aerosol backscatter and attenuation (1983)
    In:  Other Sources
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    Publication Date: 2019-07-27
    Description: A coherent laser radar system using a grating-tunable, injection-locked TEA-CO2 transmitter is being used to measure the altitude dependence of atmospheric aerosol backscatter and attenuation at a variety of CO2 laser wavelengths in the 9-11 micron region. Injection control of the TEA-CO2 laser allows one to obtain Single-Longitudinal-Mode (SLM) pulses which will follow the frequency of the injected radiation if the TEA laser cavity length is adjusted so that a cavity resonance is in proximity with the injected signal frequency, and if various additional conditions are satisfied. Requirements for generation of SLM pulses in this manner from a TEA CO2 laser with an unstable resonator cavity will be discussed. Procedures used for quantitative range-gated measurements of aerosol backscatter and attenuation will also be discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Coherent infrared radar systems and applications II; April 7, 8, 1983; Arlington, VA
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  • 171
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    Short wavelength infrared hybrid focal plane arrays (1983)
    In:  Other Sources
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    Publication Date: 2019-07-27
    Description: The employment of area focal plane arrays (FPA) has made it possible to obtain second generation infrared imaging systems with high resolution and sensitivity. The Short Wavelength Infrared (SWIR) region (1-2.5 microns) is of importance for imaging objects at high temperature and under conditions of reflected sunlight. The present investigation is concerned with electrooptical characterization results for 32 x 32 SWIR detector arrays and FPAs which are suitable for use in a prototype imaging spectrometer. The employed detector material is Hg(1-x)Cd(x)Te grown by liquid phase epitaxy on a CdTe transparent substrate. Attention is given to details of processing, the design of the detector array, the multiplexer, the fabrication of the hybrid FPA, and aspects of performance.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Technical issues in infrared detectors and arrays; April 5, 6, 1983; Arlington, VA
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  • 172
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    Overview of remote sensing field research - Requirements and status (1983)
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    Publication Date: 2019-06-28
    Description: The history of the development of remote sensing is briefly discussed, taking into account the study of the optical spectral properties of plants in the early 1950s, the concept of 'spectral signature', the multispectral scanner, and the Thematic Mapper scanner. The present state of development of remote sensing is examined. It is found that the requirements for field measurements for remote sensing field research are the same as the requirements envisioned in the 1960s. However, improved models for predicting scene reflectance and considerable field experience have clarified the aims and procedures. Information related to the status of optical measurements for crops and soils research is presented.
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  • 173
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    Microwave holographic surface measurement of the Tidbinbilla 64-m antenna (1983)
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    Publication Date: 2019-06-28
    Description: The use of a holographic technique for accurately measuring the surface figure of the Tidbinbilla (Canberra, Australia) 64-m antenna is described. Described by Bennet et al. (1976) and Scott and Ryle (1977), the technique consists of measuring the complex far-field response of the antenna at a single frequency using a terrestrial, satellite-borne or celestial radiation source of small angular diameter. This two-dimensional pattern is then Fourier transformed to yield the complex illumination function across the antenna aperture; antenna surface deviations are manifested as phase fluctuations in this function. The speed and low cost of using the technique are real advantages where observing schedules with the telescopes are heavily subscribed. For the 64-m antenna, the unweighted rms surface deviation is found to be about 1.8 mm; when weighted by the radial amplitude taper it is about 1.1 mm. Two earlier estimates by other methods had yielded tolerances of about 1.2 mm rms and 1.1 mm rms. It is planned to use the technique to survey the 22-m antennas of the Australian Telescope accurate to approximately 0.1 mm rms near 10 Ghz.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Astronomical Society of Australia, Proceedings (ISSN 0066-9997); 5; 2 19
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  • 174
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    Fiber optics for astronomical spectroscopy - The Medusa Spectrograph (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: An instrument has been built to obtain simultaneous spectra of 32 objects in the field of view of the Steward Observatory 2.3 m telescope. Short lengths of optical fiber are used to bring light from galaxy images at the focus of the telescope into a line at the spectrograph slit. This multi-fiber aperture plate instrument has been dubbed the Medusa Spectrograph. The Medusa is now producing spectra of about 100 galaxies per clear night. An optimized version of the instrument called the MX Spectrometer is being constructed to record spectra at a higher rate. This new instrument will have remotely positioned fibers under computer control. A Charge Coupled Device will be used as the spectrograph detector to allow sky subtraction, give increased dynamic range and provide more accurate wavelength calibration. Transmission characteristics of some commercial fibers are discussed, and the microlens optics used to match the telescope and the spectrograph to the fibers to avoid focal ratio degradation are described.
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  • 175
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    A mercuric iodide detector system for X-ray astronomy. I - Design considerations and predictions of background and sensitivity (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Since the discovery of Sco X-1 initiated X-ray astronomy in 1962, this science has progressed in connection with the placement of X-ray photon detectors above the atmosphere by means of rockets, balloons, and satellites. In the last few years, studies have been conducted regarding the use of mercuric iodide (HgI2) as room temperature X-ray detector for applications in hard X-ray astronomy. These detectors combine a high quantum efficiency with good energy resolution. The sensitivity of an astronomical X-ray telescope is discussed, and a description is presented of a specific design accepted for the HDXT to be flown on Spacelab. Attention is given to predictions of the background counting rate of the detector assembly in this design, taking into account the results of a Monte Carlo simulation of the detector assembly in the radiation environment at balloon altitudes (40 km).
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nuclear Instruments and Methods (ISSN 0167-5087); 213; 133-144
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  • 176
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    High spectral resolution lidar to measure optical scattering properties of atmospheric aerosols. II - Calibration and data analysis (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The high spectral resolution lidar (HSRL) measures optical properties of atmospheric aerosols by interferometically separating the elastic aerosol backscatter from the Doppler broadened molecular contribution. Calibration and data analysis procedures developed for the HSRL are described. Data obtained during flight evaluation testing of the HSRL system are presented with estimates of uncertainties due to instrument calibration. HSRL measurements of the aerosol scattering cross section are compared with in situ integrating nephelometer measurements.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 22; 3725-373
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  • 177
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    Picosecond measurements using photoacoustic detection (1983)
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    Publication Date: 2019-06-28
    Description: A report is presented of experimental results on picosecond time-resolved photoacoustic measurements of excited-state lifetimes, cross sections, and polarization properties for organic dye molecules in solution, using a new technique in which the total photoacoustic impulse produced by two ultrashort optical pulses with variable time delay between them is detected. The picosecond photoacoustic detection technique reported here appears to be a promising new way to observe weak excited-state cross sections and to perform picosecond lifetime measurements in a large variety of weakly absorbing and/or nonfluorescing atomic and molecular systems.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Journal of Quantum Electronics (ISSN 0018-9197); QE-19; 1551-155
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  • 178
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    The pressure multiplier revisited (1983)
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    Publication Date: 2019-06-28
    Description: Pressure multipliers, which were originally intended to continuously sample an unknown pressure and increase it by a known factor, so that measurements could be conducted at low pressures with liquid-in-gas gauges, may be usefully applied to the increasing number of components available for use in molecular flow networks. An intriguing possibility involves the electric control of pressure multiplier gain by means of a piezoelectric valve.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Vacuum Science and Technology A (ISSN 0734-2101); 1; 1875-187
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  • 179
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    Performance and materials aspects of Ge:Be photoconductors (1983)
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    Publication Date: 2019-06-28
    Description: Ge:Be photoconductors have been developed for low photon background applications in the 30 - 50 micron wavelength region. These detectors provide higher responsivity and lower noise equivalent power (NEP) than the Ge:Ga detectors currently operating in this wavelength range. Beryllium-doped single crystals were grown by the Czochralski method from a carbon susceptor under a vacuum of approximately 10 to the -6th torr. An optimum detective quantum efficiency of 46 percent at a background flux of 1.5 x 10 to the 8th photons/second (7 x 10 to the -13th W is reported. Ge:Be detector performance is strongly influenced by the absolute concentrations and the concentration ratio of residual shallow donors and shallow acceptors.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 4; 945-954
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  • 180
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    Neutron-transmutation-doped germanium bolometers (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Six slices of ultra-pure germanium were irradiated with thermal neutron fluences between 7.5 x 10 to the 16th and 1.88 x 10 to the 18th per sq cm. After thermal annealing the resistivity was measured down to low temperatures (less than 4.2 K) and found to follow the relationship rho = rho sub 0 exp(Delta/T) in the hopping conduction regime. Also, several junction FETs were tested for noise performance at room temperature and in an insulating housing in a 4.2 K cryostat. These FETs will be used as first stage amplifiers for neutron-transmutation-doped germanium bolometers.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 4; 933-943
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  • 181
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    High spectral resolution lidar to measure optical scattering properties of atmospheric aerosols. I - Theory and instrumentation (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A high spectral resolution lidar technique to measure optical scattering properties of atmospheric aerosols is described. Light backscattered by the atmosphere from a narrowband optically pumped oscillator-amplifier dye laser is separated into its Doppler broadened molecular and elastically scattered aerosol components by a two-channel Fabry-Perot polyetalon interferometer. Aerosol optical properties, such as the backscatter ratio, optical depth, extinction cross section, scattering cross section, and the backscatter phase function, are derived from the two-channel measurements.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 22; 3716-372
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  • 182
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    Droplet sizes and velocities in vaporizing sprays (1983)
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    Publication Date: 2019-06-28
    Description: A pulse height laser Doppler anemometer particle sizing technique has been refined to permit simultaneous particle size and velocity measurements in sprays. The improvements include (1) the use of a specially tailored 'top hat' light distribution, to provide unambiguous particle diameter-signal amplitude relations, (2) the use of back scattered light collection, and (3) the utilization of Mie theory to compute the relations between signal amplitude and particle diameter, in the backscatter mode. Twin-fluid atomized kerosene sprays have been investigated using the new technique. In these sprays distributions have been mapped of mean droplet diameters, droplet size distributions, and the local correlations between droplet diameters and velocities. The data show the variation of spray structure with atomizer input parameters, the preferential vaporization of smaller droplets, and the differing trajectories of the large and small droplets.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Combustion and Flame (ISSN 0010-2180); 54; 15-22
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  • 183
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    A new thermal radiation detector using optical heterodyne detection of absorbed energy (1983)
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    Publication Date: 2019-06-28
    Description: The operating principles of a new kind of room-temperature thermal radiation detector are described. In this device modulated light heats a gas, either directly or by conduction from a thin absorbing membrane, and the resultant change in density of the gas is detected by optical heterodyning. The performance of a membrane device of this kind agrees well with the predictions of theory.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Infrared Physics (ISSN 0020-0891); 23; 177-182
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  • 184
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    Eddy current X-Y scanner system (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: The Nondestructive Evaluation Branch of the Materials and Processes Laboratory became aware of a need for a miniature, portable X-Y scanner capable of performing eddy current or other nondestructive testing scanning operations such as ultrasonic, or small areas of flat plate. The technical description and operational theory of the X-Y scanner system designed and built to fulfill this need are covered. The scanner was given limited testing and performs according to its design intent, which is to scan flat plate areas of approximately 412 sq cm (64 sq in) during each complete cycle of scanning.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-82513 , NAS 1.15:82513
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  • 185
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    Application of the Parker flash method to high temperature thermoelectrics (1983)
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    Publication Date: 2019-06-28
    Description: Mathematical aspects of thermal diffusivity measurements are reviewed and applied to develop an experimental setup at JPL. Certain approximations commonly appearing in the literature are examined in some detail and rejected based upon sensitive slope variations having significant impact on the results. The final mathematical formulation used was one developed by Parker et al. (1961), which evaluated the diffusivity in a way that could be simply evaluated by examining an oscilloscope trace. A computer algorithm was written to examine solution sensitivity to the number of terms taken in the infinite series. The mathematical technique is being used at JPL to evaluate diffusivities of graphite, Boron Carbon and Lanthanum Sulphur compounds in the temperature range of 300 K to 1200 K.
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  • 186
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    The use of heterodyne speckle photogrammetry to measure high-temperature strain distributions (1983)
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    Publication Date: 2019-06-28
    Description: Thermal and mechanical strains have been measured on samples of a common material used in jet engine burner liners, which were heated from room temperature to 870 C and cooled back to 220 C, in a laboratory furnace. The physical geometry of the sample surface was recorded to select temperatures by means of a set of twelve single-exposure specklegrams. Sequential pairs of specklegrams were compared in a heterodyne interferometer which allowed high-precision measurement of differential displacements. Good speckle correlation was observed between the first and last specklegrams also, which showed the durability of the surface microstructure, and permitted a check on accumulated errors. Agreement with calculated thermal expansion was to within a few hundred microstrain over a range of fourteen thousand.
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  • 187
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    Radar image registration and rectification (1983)
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    Publication Date: 2019-06-28
    Description: Two techniques for radar image registration and rectification are presented. In the registration method, a general 2-D polynomial transform is defined to accomplish the geometric mapping from one image into the other. The degree and coefficients of the polynomial are obtained using an a priori found tiepoint data set. In the second part of the paper, a rectification procedure is developed that models the distortion present in the radar image in terms of the radar sensor's platform parameters and the topographic variations of the imaged scene. This model, the ephemeris data and the digital topographic data are then used in rectifying the radar image. The two techniques are then used in registering and rectifying two examples of radar imagery. Each method is discussed as to its benefits, shortcomings and registration accuracy.
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  • 188
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    Lead sulfide - Silicon MOSFET infrared focal plane development (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A process for directly integrating photoconductive lead sulfide (PbS) infrared detector material with silicon MOS integrated circuits has been developed primarily for application in long (greater than 10,000 detector elements) linear arrays for pushbroom scanning applications. The processing technology is based on the conventional PMOS and CMOS technologies with a variation in the metallization. Results and measurements on a fully integrated eight-element multiplexer are shown.
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  • 189
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    Calibration of a stack of NaI scintillators at the Berkeley Bevalac (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: An analysis of the carbon and argon data reveals that essentially all of the charge-changing fragmentation reactions within the stack can be identified and removed by imposing the simple criteria relating the observed energy deposition profiles to the expected Bragg curve depositions. It is noted that these criteria are even capable of identifying approximately one-third of the expected neutron-stripping interactions, which in these cases have anomalous deposition profiles. The contribution of mass error from uncertainty in delta E has an upper limit of 0.25 percent for Mn; this produces an associated mass error for the experiment of about 0.14 amu. It is believed that this uncertainty will change little with changing gamma. Residual errors in the mapping produce even smaller mass errors for lighter isotopes, whereas photoelectron fluctuations and delta-ray effects are approximately the same independent of the charge and energy deposition.
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  • 190
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    Calibration of an aerogel counter of index 1.1 at the Bevalac (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The counter, which is exposed to sea level muons and to a beam of relativistic Mn-55, is 6 cm thick and approximmately 60 cm in diameter; it is viewed by twelve 12.7-cm-diameter photomultipliers. It comprises a mosaic with 48 aerogel pieces whose refractive indices are approximately 1.1. It is pointed out that a relativistic muon produces typically 23 + or - 4 photo-electrons. The light yield, which is mapped as a function of position, has an r.m.s. variation of less than 1 percent per cm. An analysis of the light yield suggests that absorption is important at short wavelengths. The calibration reveals that the light yield and uniformity of the counter are sufficient to determine particle velocity in the gamma range from 2.4 to 3.1.
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  • 191
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    Flow velocity measurements with stimulated Rayleigh-Brillouin-gain spectroscopy (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Using stimulated Rayleigh-Brillouin-gain spectroscopy, velocity measurements in an atmospheric-pressure subsonic nitrogen flow with 10 percent uncertainty have been conducted. It is shown that the accuracy of the velocity measurements increases with gas pressure, making this spectroscopic technique ideal for measuring velocity and other parameters of high-pressure (greater than 1-atm) atomic or molecular flows.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optics Letters (ISSN 0146-9592); 8; 602-604
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  • 192
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    Analysis of strain gage reliability in F-100 jet engine testing at NASA Lewis Research Center (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A reliability analysis was performed on 64 strain gage systems mounted on the 3 rotor stages of the fan of a YF-100 engine. The strain gages were used in a 65 hour fan flutter research program which included about 5 hours of blade flutter. The analysis was part of a reliability improvement program. Eighty-four percent of the strain gages survived the test and performed satisfactorily. A post test analysis determined most failure causes. Five failures were caused by open circuits, three failed gages showed elevated circuit resistance, and one gage circuit was grounded. One failure was undetermined.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-83325 , NAS 1.15:83325
    Format: application/pdf
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  • 193
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    Dynamic-pressure measurements using an electronically scanned pressure module (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Frequency response was measured for different lengths and diameters of tubing between a sinusoidal pressure source and a pressure sensing module from an electronically scanned pressure measuring system. Measurements were made for straight runs of both steel and vinyl tubing. For steel tubing, measured results are compared with results calculated by using equations developed by Tijdeman and Bergh. Measurements were also made with a bend in the vinyl tubing at the module. In addition, measurements were made with two coils placed in the tubing near the middle of the run.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-TM-84650 , L-15583 , NAS 1.15:84650
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  • 194
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    Estimating time and time-lag in time-of-flight velocimetry (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Estimating time and time-lag in time-of-flight velocimeters is investigated. Statistics of a filtered Poisson point process is given. A Maximum Likelihood Estimator is compared with suboptimum estimators in terms of robustness. For a dominating background combined spatial and temporal processing can improve the robustness compared with purely temporal processing. Schemes for the spatial filters are given.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 22; 3637-364
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  • 195
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    Directional velocity analyzer for measuring electron distribution functions in plasmas (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A directional velocity analyzer has been developed for measuring electron distribution functions in plasmas. It contains a collimating aperture which selects particles from a narrow cone in velocity space and a retarding potential analyzer. The distribution function f(v, theta, phi) is obtained from a large number of analyzer traces taken at different angles theta, phi. In addition, the small analyzer can be moved in space and the measurements are time resolved so as to obtain the complete phase space information f(v,r,t). The large data flow of this seven-variable function is processed with a high-speed digital data-acquisition system. The new electron velocity analyzer is applicable over a wide parameter range in electron energies and densities. Various cases of anisotropic distributions such as beams, shells, tails, and drifts have been successfully investigated.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 54; 1302-131
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  • 196
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    Spatially and spectrally resolved multipoint coherent anti-Stokes Raman scattering from N2 and O2 flows (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Single-shot spectrally resolved broadband rotational coherent anti-Stokes Raman scattering (CARS) from multiple points along a line intersecting a flow has been observed for N2 and O2. A large-angle phase-matching configuration was used to achieve spatial resolution of 0.1 mm x 0.1 mm x 0.1 mm for each of 20 points in the interaction volume. Single-shot multipoint CARS of N2 at different temperatures and of several species in a coflowing jet was observed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optics Letters (ISSN 0146-9592); 8; 599-601
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  • 197
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    Automated control and data acquisition for a tunable diode laser heterodyne spectrometer (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: This paper describes the hardware and software design, development, and implementation of the control and data electronics of a laser heterodyne spectrometer instrument being built at NASA Langley Research Center for a technology demonstration. Functional partitioning, applied at all levels of hardware and software, has been found to provide expedient design, development, and testing of the instrument. The instrument is composed of distributed microprocessor-based units. A master/slave protocol is presented which can be simulated by a terminal for unit checkout. All but one of the units are implemented using a set of core boards, plus unique boards where necessary. This design has led to reduced hardware development, reduced parts inventory, and replication of software modules, while providing the flexibility needed for a development instrument. The development tools and documentation guidelines are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 83-2378
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  • 198
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    Infrared astronomical imaging using a microcomputer data system (1983)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A small, portable data-acquisition and display system with a unique coprocessor was designed and built to collect data from infrared array detectors for astronomical and laboratory use. The system consists of a microcomputer board, two 12-bit analog-to-digital data-acquisition boards, a color-graphics driver board, and two coprocessor boards. The coprocessors are arithmetic logic units designed to achieve the high computation rates necessary for real-time infrared background cancellation. The system can collect data from infrared detectors of 1 to 256 pixel elements with a computation rate of 768 kHz. The software for the system was designed to collect data in the system's background, while performing other tasks in the system's foreground. The data for the detector arrays is stored in block fashion to facilitate variable image size.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 83-2377
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  • 199
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    Constant-temperature hot-wire anemometer practice in supersonic flows. II - The inclined wire (1983)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: The performance of a constant-temperature inclined hot-wire in a supersonic flow is critically examined. It is shown that calibration techniques applicable to subsonic flow, such as the cosine cooling law cannot be used when the flow is supersonic. Calibration and measurement procedures appropriate to supersonic flow are suggested, together with the possible limits on their validity. Experimental results for different wires indicate that the sensitivities do not seem to depend on flow direction according to any simple correlation. When the sensitivity exhibits a strong dependence on flow direction, the wire should be discarded to avoid errors due to nonlinear effects.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 83-0508 , American Institute of Aeronautics and Astronautics, Aerospace Sciences Meeting; Jan 10, 1983 - Jan 13, 1983; Reno, NV
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  • 200
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    Laser holographic interferometry for an unsteady airfoil in dynamic stall (1983)
    In:  Other Sources
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    Publication Date: 2019-07-13
    Description: Laser holographic interferometry was used to study a two-dimensional NACA 0012 airfoil undergoing dynamic stall. The airfoil, fabricated from graphite fiber and epoxy, was tested at Mach numbers of 0.3 to 0.6, at Reynolds numbers of 500,000-2,000,000, at reduced frequencies of 0.015 to 0.15, and at mean angles of attack of 0-10 deg with amplitudes of 10 deg. Density and pressure fields were obtained from dual-plate interferograms. Double-pulse interferograms, which seemed to show the wake boundaries better, were also taken. Comparisons of pressures with orifice pressures were good for the attached flow cases. For the separated flow cases, which had a vortex enbedded in the flow, the comparisons were poor. Vortices, wake structures, and the dynamic stall process can be seen by holographic interferometry.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA PAPER 83-0388 , American Institute of Aeronautics and Astronautics, Aerospace Sciences Meeting; Jan 10, 1983 - Jan 13, 1983; Reno, NV
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