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  • Other Sources  (3,756)
  • INSTRUMENTATION AND PHOTOGRAPHY  (2,553)
  • FLUID MECHANICS  (1,203)
  • Cell & Developmental Biology
  • General Chemistry
  • 1970-1974  (3,753)
  • 1945-1949  (3)
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  • 1
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    In:  CASI
    Publication Date: 2006-05-07
    Description: A software/hardware system designed and developed to perform automated video imagery analysis is described. Major elements included in the analysis system are: (1) sampling oscilloscope; (2) programmable trigger unit; (3) central computer; and (4) software processing library. The function of the scope and trigger unit, in conjunction with the control computer, is to digitize the selected portion of the video image and store as amplitude and time data in computer memory. Evaluation of the video data, analogus to interpretation of a visual image, is accomplished by the processing software. It is indicated that this technique of video image analysis is applicable to a wide variety of nonaerospace applications involving video data and image analysis.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Chamber of Commerce Proc. of the 1st 1974 Technol. Transfer Conf.; p 181-188
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  • 2
    Publication Date: 2006-01-11
    Description: Problems of laboratory simulation of artificial earth satellite flight conditions in the ionosphere are examined, and a setup capable of reproducing the basic parameters of ion flows (with energies of 5-10 eV, energy spectrum width approximately 2x5 eV, and an intensity of 10 to the minus 8th power a/cm/2) past measurement instruments and satellite models is described. Possibilities for further improvement of the apparatus are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 282-291
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  • 3
    Publication Date: 2006-01-11
    Description: A real time, computerized, measurement method for the effective perceived noise level is reported that uses comparison of two sounds differing in level and frequency to obtain the noise intensity emitted by aircraft and to calculate human psychoacoustic annoyance reactions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: the 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 224-232
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  • 4
    Publication Date: 2006-01-11
    Description: An objective method and apparatus for noise control and acoustic diagnostics of motorcar engines are reported. The method and apparatus let us know whether the noisiness of the vehicle under test exceeds the admissible threshold levels given by appropriate standards and if so what is the main source of the excessive noise. The method consists in measuring both the overall noise level and the sound pressure levels in definite frequency bands while the engine speed is controlled as well and may be fixed at prescribed values. Whenever the individually adjusted threshold level has been exceeded in any frequency band, a self-sustaining control signal is sent.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics Vol. 1A (NASA-TT-F-15375); p 198-204
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  • 5
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    In:  CASI
    Publication Date: 2006-01-11
    Description: The principle types of silencers are discussed for gas dynamic noise of free steam and gas expansions, as well as the results of research in gas dynamics of jets and applied acoustics. Gas dynamic noise attenuation by means of the Coanda effect is due to fluid decompression in a Coanda ejector of the external type, where a structural change takes place in the acoustic frequency spectrum and in its direction, as well as a substantial decrease in the fluid's velocity, temperature and concentration. This process is continued in the second phase with absorption of the acoustic waves by means of an active structure.
    Keywords: FLUID MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 143-149
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  • 6
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    In:  CASI
    Publication Date: 2006-01-11
    Description: A seismic torsiometer is described which is based on the reception by a photosensitive transducer of a light flux modulated by a relative rotation of the optical axes of two polaroids. The torsional vibrations of the polaroid fixed to the shaft are transmitted to the other polaroid (which at the same time is the seismic mass of the apparatus) by means of elastic lamellas. The device can work as accelerometer, vibrometer or frequency meter, depending on the value of the ratio between the proper oscillation frequency of the seismic system and the measured vibration frequency.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 68-72
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  • 7
    Publication Date: 2006-01-11
    Description: The demands placed upon vibration and noise measuring instruments are discussed. The instruments that are now being manufactured in the RSR are described, as well as those that are being made ready for manufacture, namely: the VP-3 portable vibrometer, the N2103 precision electronic vibrometer, the N2103 B sonometric preamplifier, as well as vibration transducers of the electrodynamic and piezoelectric types.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 62-67
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  • 8
    Publication Date: 2006-01-11
    Description: After discussing the principal calibration methods for piezoelectric accelerometers, an experimental setup for accelerometer calibration by the reciprocity method is described It is shown how the use of a lock-in voltmeter eliminates errors due to viscous damping and electrical loading.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 55-61
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  • 9
    Publication Date: 2006-01-11
    Description: An absolute two-sided radiometer, designed on the principle of replacing absorbed radiant energy with electrical energy, is described. The sensitive element of the detector is a thermoelectric transducer of thermal flux. The fabrication technology, methods of measurement, technical characteristics, and general operation of the instrument are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Space Res. in the Ukraine, No. 3 (NASA-TT-F-15537); p 95-101
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  • 10
    Publication Date: 2011-08-16
    Description: A measurement system using a deceleration probe was designed for determining the local values of gas and liquid mass flux in various gas/liquid droplet sprayfields. The system was used to characterize two-phase flowfields generated by gas/liquid rocket-motor injectors. Measurements were made at static pressures up to 500 psia and injected mass flow ratios up to 20. The measurement system can also be used at higher pressures and in gas/solid flowfields.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 11
    Publication Date: 2011-08-16
    Description: The AEROS Neutral Atmosphere Temperature Experiment (NATE) is designed to measure the kinetic temperature of molecular nitrogen in the thermosphere. A quadrupole mass spectrometer tuned to N2 measures the N2 density variation in a small spherical antechamber having a knife-edged orifice which is exposed to the atmosphere at the outer surface of the spacecraft. The changing density of N2 due to the spinning motion of the spacecraft permits determination of the velocity distribution of the N2 from which the temperature is calculated. An alternate mode of operation of the instrument allows measurement of the other gases in the atmosphere as well as N2 permitting determination of the neutral particle composition of the atmosphere.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Zeitschrift fuer Geophysik; 40; 5, 19; 1974
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  • 12
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    Publication Date: 2011-08-16
    Description: A CO2 laser Doppler detection system has been developed to measure remotely the true airspeed of an aircraft. The system uses a 50-W sealed-off CO2 laser in a homodyne detection system employing a collinear optical telescope, a HgCdTe detector, and a frequency tracking loop. The system was successfully flight-tested on a NASA Convair 990 research aircraft during December 1971 and June 1972. The results indicate that an airspeed measurement under clear weather conditions is feasible up to an altitude of 3000 m with an error of less than 0.5%.-
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Dec. 197
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  • 13
    Publication Date: 2011-08-16
    Description: Preliminary data are given for the SAS-2 high energy galactic gamma ray observation. These data include both latitude and longitude distributions. The longitude distribution shows a high density region. The latitude distributions toward the center and the anti-center are markedly different, the former showing a two-component structure of half-widths of approximately 3 and 6 deg. The energy spectrum in the range 35 to 200 MeV is hard, consistent with cosmic ray interactions with interstellar matter, including neutral pions decay and emission from energetic electron interactions. The data is consistent with an interpretation in terms of the confinement of the cosmic rays in the spiral arms.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: ESRO The Context and Status of Gamma Ray Astronomy; p 201-204
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  • 14
    Publication Date: 2011-08-16
    Description: Description of a diagnostic technique for determining the unsteady character of turbulent boundary-layer separation. The technique uses thin platinum films mounted flush with the model surface. Voltages from these films provide measurements related to the flow character above the film. For illustration, results obtained by this technique are presented for the interaction of a hypersonic shock wave and a turbulent boundary layer, with and without separation.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Oct. 197
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  • 15
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: The performances of a wedge-type gas-sampling probe and pitot probes are compared in applications to flowfield profile studies. The flow structure data obtained by these techniques are found to agree well in flow regions with and without significant gradients. The wedge-type probe showed a good service life and allowed a substantial reduction of the sampling time. The wedge probe design is discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal; 12; Sept
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  • 16
    Publication Date: 2011-08-16
    Description: We present a new technique for the correction of atmospheric distortion in telescope images. Most of this distortion arises from a random phase variation of the incoming light across the telescope aperture. This variation limits the resolving power of even large telescopes to about one arc second. If the sharpness of the images is defined in a suitable way, this sharpness is maximized only when the phase distortion of the incoming light is zero. We present computer simulations of a simple feedback system in which active optical elements, set to maximize the sharpness, correct most of the atmospheric distortion. Photon statistics set the limiting magnitude of the object for which a practical feedback system can work. Details in a sixth magnitude object smaller than 0.1 sec of arc should be resolvable. The system can be conveniently employed within existing telescopes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Society of America; vol. 64
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  • 17
    Publication Date: 2011-08-16
    Keywords: FLUID MECHANICS
    Type: Journal of Fluid Mechanics; 65; Aug. 12
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  • 18
    Publication Date: 2011-08-16
    Description: A systematic performance analysis of aplanatic Cassegrainian telescopes has been accomplished by means of a ray trace program. The results indicate that the available field angle for a given geometric spot size is, to a very close approximation, a function of the relative back focal distance only. Image curvatures, as computed by third-order theory and by the ray trace program, were found to be in very close agreement. Image curvature is plotted as a function of the ray height ratio for a wide range of secondary magnification.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Sept
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  • 19
    Publication Date: 2011-08-16
    Description: Software application or development in optical image digital data processing requires a fast, good quality, yet inexpensive hard copy of processed images. To achieve this, a Cambo camera with an f 2.8/150-mm Xenotar lens in a Copal shutter having a Graflok back for 4 x 5 Polaroid type 57 pack-film has been interfaced to an existing Adage, AGT-30/Electro-Mechanical Research, EMR 6050 graphic computer system. Time-lapse photography in conjunction with a log to linear voltage transformation has resulted in an interactive system capable of producing a hard copy in 54 sec. The interactive aspect of the system lies in a Tektronix 4002 graphic computer terminal and its associated hard copy unit.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Sept
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  • 20
    Publication Date: 2011-08-16
    Description: The early and intermediate development of a highly accelerated (or decelerated) turbulent boundary layer is analyzed. For sufficiently large accelerations (or pressure gradients) and for total normal strains which are not excessive, the equation for the Reynolds shear stress simplifies to give a stress that remains approximately constant as it is convected along streamlines. The theoretical results for the evolution of the mean velocity in favourable and adverse pressure gradients agree well with experiment for the cases considered. A calculation which includes mass injection at the wall is also given.
    Keywords: FLUID MECHANICS
    Type: Journal of Fluid Mechanics; 64; July 24
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  • 21
    Publication Date: 2011-08-16
    Description: An interferometric device designed to be located in the focal plane of a large astronomical telescope is presented. The prime application is for the forthcoming large space telescope. The device is to perform interferometry on the optical wavefront arising from a single star after it has propagated through the telescope. The concept of a focal plane figure sensor has been experimentally verified by fabricating and testing an operating laboratory breadboard figure sensor. A set of linear independent control equations are derived that define the operations for utilizing a focal plane figure sensor in the control loops for the positioning of the secondary mirror and for the active control of the primary mirror optical figure. A number of scientific experiments that could be performed with the interferometer are also briefly discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Aug. 197
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  • 22
    Publication Date: 2011-08-16
    Description: The Raman scattering technique was applied to measure the local static temperature and gas number density over a sharp-edge flat-plate model in a Mach 5 nozzle of the Langley nozzle test chamber with air as the test gas. The angle of attack varied from -5 to 15 deg, and the stagnation temperature varied from 317 to 442 K, with stagnation pressures ranging from 170 kN to 2.8 MN/sq m. The measured values of static temperature and density ranged from 60 to 100 K and from 0.03 to 0.8 kg/cu m, respectively. A comparison with calculated values based on static pressure measurements along the model shows that the Raman scattering technique is a viable measurement method in applications to high-speed three-dimensional flows.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal; 12; Aug. 197
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  • 23
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    Publication Date: 2011-08-16
    Description: The first part of the present theory is devoted to the derivation of a Fokker-Planck equation. The eddies smaller than the hydrodynamic scale of the diffusion cloud form a diffusivity, while the inhomogeneous, bigger eddies give rise to a nonuniform migratory drift. This introduces an eddy-induced shear which reflects on the large-scale diffusion. The eddy-induced shear does not require the presence of a permanent wind shear and is intrinsic to the diffusion. Secondly, a transport theory of diffusivity is developed by the method of repeated-cascade and is based upon a relaxation of a chain of memories with decreasing information. The full range of diffusion consists of inertia, composite, and shear subranges, for which variance and eddy diffusivities are predicted. The coefficients are evaluated. Comparison with experiments in the upper atmosphere and oceans is made.
    Keywords: FLUID MECHANICS
    Type: Zeitschrift fuer Naturforschung; vol. 29a
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  • 24
    Publication Date: 2011-08-16
    Description: Determination of the properties of the system transfer function of the vertical-velocity propeller anemometer. A treatment of this problem is presented which is based on an analysis of estimates of the system transfer function derived from estimates of spectra calculated from time histories of indicated vertical velocity and on estimates of the associated input Eulerian vertical-velocity frequency spectra based on the hypothesis that instrument degradation of the Fourier components occurs in the inertial subrange.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Boundary-Layer Meteorology; 6; May-June
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  • 25
    Publication Date: 2011-08-16
    Description: The error minimization method proposed by Nachtsheim and Swigert (1965) to satisfy the asymptotic boundary conditions of boundary layer equations is proved to be equivalent to imposing the condition of fastest decay. As a consequence, a uniqueness problem is not arising in the solutions of boundary layer equations obtained by their method.
    Keywords: FLUID MECHANICS
    Type: Computers and Fluids; 2; Mar. 197
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  • 26
    Publication Date: 2011-08-16
    Description: In one attempt to produce a simple inexpensive nozzle, a 2-in. diam plate with 37 holes was investigated (Stadler, 1960), anticipating that the small jets emanating from the plate would combine to form a uniform stream. This experiment was unsuccessful because a uniform flow was not established until the flow had progressed many nozzle diameters downstream. However, an extension of this concept to a much larger number of very small jets, viz., a porous plate, did provide a method for producing a uniform, low Reynolds number jet almost immediately downstream of the nozzle (Greene, 1973). The method is described and some typical jet velocity profiles for nozzle Reynolds numbers from 50 to 1000 are given.
    Keywords: FLUID MECHANICS
    Type: Journal of Spacecraft and Rockets; 11; Aug. 197
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  • 27
    Publication Date: 2011-08-16
    Description: An upconverter has been used to convert infrared photons from astronomical sources to higher frequency quanta that were detected with a pulse-counting photomultiplier photometer. It is pointed out that these observations represent the first successful astronomical demonstration of infrared upconversion. Upconversion is carried out in an optically nonlinear medium, which in the upconverter described is a lithium iodate crystal. A 0.6943-micrometer high peak power ruby laser pump was developed for the demonstration.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nature; 249; June 14
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  • 28
    Publication Date: 2011-08-16
    Description: The autoranging scanning system discussed combines in a unique way four different methods for removing noise. The system employs a narrow-band amplifier. Other noise reduction methods make use of digital summation, convolution numbers, and the coaddition of scans. The system was designed to digitize the output of an infrared spectrometer and to record it on magnetic tape. Light passes through a mechanical light chopper and the spectrometer optics, and falls on the PbS cell to produce a signal which is amplified by the first preamplifier.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 45; July 197
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  • 29
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    Publication Date: 2011-08-16
    Description: Some recent developments in coherent optical processing are described in this paper. Specifically, the use of one or more elementary gratings to perform useful processing operations and computer-generated spatial filters to obtain generalized transforms are discussed. Applications incorporating nonlinear optical elements and optical feedback into the processing system are also presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering; 13; May-June
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  • 30
    Publication Date: 2011-08-16
    Description: Equations for the fluctuation correlation in an incompressible shear flow are derived on the basis of kinetic theory, utilizing the two-point distribution function which obeys the BBGKY hierarchy equation truncated with the hypothesis of 'ternary' molecular chaos. The step from the molecular to the hydrodynamic description is accomplished by a moment expansion which is a two-point version of the thirteen-moment method, and which leads to a series of correlation equations, viz., the two-point counterparts of the continuity equation, the Navier-Stokes equation, etc. For almost parallel shearing flows the two-point equation is separable and reduces to two Orr-Sommerfeld equations with different physical implications.
    Keywords: FLUID MECHANICS
    Type: Physics of Fluids; 17; Jan. 197
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  • 31
    Publication Date: 2011-08-16
    Description: Measurements taken in a Mach-2.9 turbulent boundary layer are shown to demonstrate the ability of a laser velocimeter to measure the turbulence transport properties of high-speed compressible flows. This demonstrated ability, combined with the nonperturbing quality and relative insensitivity to environmental conditions of the laser velocimeter, opens the way to compressible flow measurements never considered possible with more conventional measurement techniques.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal; 12; May 1974
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  • 32
    Publication Date: 2011-08-16
    Description: Description of techniques for detecting and reducing to negligible values beam-radiation reflection and scattering in high vacuum target chambers used in beam foil experiments. It is suggested that all target chambers be checked in the manner described in order to discover and reduce intensity variations that may not be obvious on the usual beam-foil decay curves.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; June 197
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  • 33
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    Publication Date: 2011-08-16
    Description: The equations of motion governing steady, inviscid flow are of a mixed type, that is, hyperbolic in the supersonic region and elliptic in the subsonic region. These mathematical difficulties may be removed by using the so-called time-dependent method, where the governing equations become hyperbolic everywhere. The steady-state solution may be obtained as the asymptotic solution for large time. The object of this research was to develop a production type computer program capable of solving converging, converging-diverging, and plug two-dimensional nozzle flows in computational times of 1 min or less on a CDC 6600 computer.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Apr. 197
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  • 34
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    Publication Date: 2011-08-16
    Description: When making photographs in X rays or gamma rays with a multiple-pinhole camera, the individual images of an extended object such as the sun may be allowed to overlap. Then the situation is in many ways analogous to that in a multiplexing device such as a Fourier spectroscope. Some advantages and problems arising with such use of the camera are discussed, and expressions are derived to describe the relative efficacy of three exposure/postprocessing schemes using multiple-pinhole cameras.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Physics; 45; Apr. 197
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  • 35
    Publication Date: 2011-08-16
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Microbiology; 27; Jan. 197
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  • 36
    Publication Date: 2011-08-16
    Description: A technique is described for measuring heat transfer gaps from neutron radiographs. The method involves scanning the radiograph negative with a recording microdensitometer to obtain a trace of the optical density variation across the diameter of the capsule. The optical density change representing the gap is measured from the microdensitometer trace and related to the physical measurement. Heat transfer gaps from 0.061 to 0.178 cm have been determined by this technique and agree with preassembly physical measurements to plus or minus 0.005 cm.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Materials Evaluation; 32; Mar. 197
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  • 37
    Publication Date: 2011-08-16
    Description: The design and construction is described of a package of X-ray telescopes launched in the NASA satellite Copernicus (OAO-3), which began stellar observations in September 1972. It contains three grazing incidence reflectors covering a range of wavelengths from 0.3 to 8 nm, and having a combined collecting area of 40.9 sq cm, with angular resolutions up to 1 minute of arc. This is believed to be the first satellite application of such reflectors in stellar X-ray astronomy. A collimated detector of wavelengths 0.1-0.3 nm has a 17.8 sq cm collecting area. A visible light star tracker detects package misalignment if this should occur.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Physics; vol. 7
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  • 38
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    Publication Date: 2011-08-16
    Description: An instrument was designed and built that measures the light scattered at several angles in the forward direction simultaneously. The instrument relies on an optical multiplexing technique for frequency encoding of the different channels suitable for detection by a single photodetector. A Mie theory computer program was used to calculate the theoretical volume scattering function for a suspension of polystyrene latex spheres. The agreement between the theoretical and experimental volume scattering functions is taken as a verification of the calibration technique used.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Mar. 197
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  • 39
    Publication Date: 2011-08-16
    Description: Test flow velocities from 5 to 7 km/sec were generated in a 6-in. expansion tube using helium, argon, air, and CO2 test gases. Pitot pressure profiles across the flow at the test section are presented for the four test gases, and measured flow quantities are compared to computer predicted values. Comparison of predicted and measured flow quantities suggests the expansion to be near thermochemical equilibrium for all test gases and implies the existence of a totally reflected shock at the secondary diaphragm. Argon, air, and CO2 flows were observed to attenuate while traversing the acceleration section, whereas no attenuation was observed for helium.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Apr. 197
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  • 40
    Publication Date: 2011-08-16
    Description: A simple but useful formula describing the effect of electron gun pulse width on the time of flight (TOF) spectra measured in translational spectroscopy experiments is developed. An approximately monoenergetic pulsed electrostatically focused electron beam traverses a scattering cell filled with a Maxwellian gas. Inelastic electron collisions with the gas produce metastable particles, ions, scattered electrons, and photons which then pass through a collimating slit system at right angles to the electron beam. TOF techniques are used to separate the photon signal from the metastable particle signal and to measure the TOF distribution of the metastable species.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 45; Feb. 197
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  • 41
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    Publication Date: 2011-08-16
    Description: An optical displacement sensor is described in which only a pair of large-diameter fibers is used rather than a branched bundle of many small-diameter fibers. The basic idea of the two-fiber sensor is that the axes of the fibers are at an angle to one another at the sensor face, rather than parallel as is the case for the many-fiber configuration. The sensitivity of this two-fiber sensor is approximately the same as the most sensitive configuration of the many-fiber sensor.-
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 45; Feb. 197
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  • 42
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    Publication Date: 2011-08-16
    Description: Two configurations of an automatic bidirectional, fringe-counting corner-cube interferometer are compared. They differ only in the method of quadrature phase introduction. The one using polarization coding has good phase stability at optical path differences as large as 955 mm, the one using adjacent beams has such poor phase stability as to render it useless at path differences greater than 700 mm. A useful well-defined alignment procedure is given for the corner-cube interferometer.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments; 45; Feb. 197
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  • 43
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    Publication Date: 2011-08-16
    Description: The structure of a cylindrical blast wave with ionization at non-LTE conditions was calculated using equations previously developed by Wu and Fu (1970). The degree of ionization was predicted by a modified Saha equation. Temperature profiles show that the temperature at non-LTE conditions is lower than at LTE near the shock front. This corresponds to a higher degree of ionization for the non-LTE limit, which indicates that the neutral gas absorption is much more efficient at non-LTE than at the LTE limit. The decaying velocity under non-LTE is approximately 15% less than under LTE.
    Keywords: FLUID MECHANICS
    Type: Physical Society of Japan; vol. 36
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  • 44
    Publication Date: 2011-08-16
    Description: The application of holography to thermal stress studies is discussed. Interference fringes as produced by holograms and their interpretation are reviewed in relation to workpiece displacement. Three potential mechanisms are given to explain thermal displacement as detected by holographic methods. Results of some thermal stressing studies are reported, including tests on a live rocket motor.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Materials Evaluation; 32; Mar. 197
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  • 45
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: A nonlinear sonic system is described that includes a delay line. Short-lived pulses with a high repetition frequency circulate through the system. The analysis was carried out by defining the reflection factor at the load and then dividing the input pulse according to duration into sections of appropriate width. The response was determined for each section, the response to the whole pulse being given by the sum of the responses at the sections. This makes it possible to broach the synthesis of a sonic system that will give an output pulse of the desired form.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 177-182
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  • 46
    Publication Date: 2011-08-16
    Description: Thermoelectrets of polymers with stable surface charge on either side have been found to attract ions and charged particles to their surfaces. To assess their applicability to the control of atmospheric contamination, polytetraethylene (teflon) electrets are exposed to vapors coming from volatile mixtures over periods up to 90 min. Use is made of mass spectrometry for the analysis of teflon electret characteristics. It is found that even small quantities of the liquids in the mixture gives its characteristic mass spectra and that the peak height represents a measure for the quantity of the material collected over the electret surface, with the collected quantity being proportional to the duration of exposure.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Environmental Letters; 7; 3, 19; 1974
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  • 47
    Publication Date: 2011-08-16
    Description: A gamma-ray spectrometer has been flown on the Apollo 15 and 16 spacecraft to determine the lunar-surface composition and measure the cosmic gamma-ray flux. The instrument included a NaI(Tl) scintillation crystal coupled to a 7.6-cm photomultiplier tube, a plastic mantle for anti-coincidence rejection of charged particles, and 511 channels of analysis. Boom-mounted operation permitted a significant reduction in the background. The data were transmitted on an event-by-event basis. About 22% of the lunar surface was mapped and spectra of the cosmic gamma-ray flux over an energy range of 0.065-27.5 MeV have been obtained.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Nuclear Instruments and Methods; 118; 1974
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  • 48
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    Publication Date: 2011-08-16
    Description: A spark-chamber track-finding program has been written. The accuracy of the location of the track is good, and if the chamber contains many spurious sparks the computation time is much less than the time used by a least-squares fit routine. Multiple tracks can be found and interaction vertices can thereby be determined.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 49
    Publication Date: 2011-08-16
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Microbiology; 28; Sept
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  • 50
    Publication Date: 2011-08-16
    Description: The selection of the optimum frequency for a measuring generator for determining the value of the hydrophysical parameter with a given degree of accuracy is discussed. Methods from information theory for measuring generators are described. Conversion of the frequency of generators into digital form by means of statistical averaging is also described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Automation of the Collection and Analysis of Sci. Inform. in the Probl. of the Interaction of the Atmosphere and Ocean (NASA-TT-F-801); p 80-84
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  • 51
    Publication Date: 2011-08-16
    Description: A technique is discussed for photographic reduction of blurring which utilizes only a single photograph. No special equipment which is not available in practically any photographic laboratory is required to carry out the technique.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Space Iconics (NASA-TT-F-798); p 67-74
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  • 52
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    Publication Date: 2011-08-16
    Description: Photography and photochemical processing of the film in spacecraft phototelevision systems involve several aspects which require an approach to selection of the handling process which differs from that used under ground conditions, different processing technology, and different construction of the instrument for carrying out the processing. Soviet processing techniques and equipment are described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Space Iconics (NASA-TT-F-798); p 59-66
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  • 53
    Publication Date: 2011-08-16
    Description: A multi-slit shadow direction sensor of jalousie type (JDS) was developed to provide a simple, highly reliable tracking system to guide a rotating mirror toward the sun so that the reflected light would illuminate the input slit of a photoelectric spectrometer. The operating principle and stability are considered as well as determination of initial signal level at the output of each photosensor. A procedure is recommended for calculation of a JDS. Both one- and two-coordinate sun direction sensors are described and considered for use in the tracking system of a photoelectric spectrometer.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Equipment for Space Res. (NASA-TT-F-785); p 65-87
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  • 54
    Publication Date: 2011-08-16
    Description: When photographic equipment is miniaturized, in order to conserve weight and size for spacecraft use, by using wide angle, short focus lenses, a band-type central between-the-lens shutter must be used. The rectangular slot shape was the form with the highest optical efficiency. To overcome the problem of burrs caused in the punching out of the slots in a carbon steel band, a shape limited by arcs with radius equal to half the slot width is preferred.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Equipment for Space Res. (NASA-TT-F-785); p 42-47
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  • 55
    facet.materialart.
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    Publication Date: 2016-03-07
    Description: Geoscience instrumentation systems are considered along with questions of geoscience environment, signal processing, data processing, and design problems. Instrument platforms are examined, taking into account ground platforms, airborne platforms, ocean platforms, and space platforms. In situ and laboratory sensors described include acoustic wave sensors, age sensors, atmospheric constituent sensors, biological sensors, cloud particle sensors, electric field sensors, electromagnetic field sensors, precision geodetic sensors, gravity sensors, ground constituent sensors, horizon sensors, humidity sensors, ion and electron sensors, magnetic field sensors, tide sensors, and wind sensors. Remote sensors are discussed, giving attention to sensing techniques, acoustic echo-sounders, gamma ray sensors, optical sensors, radar sensors, and microwave radiometric sensors.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 56
    Publication Date: 2011-08-16
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Oct. 197
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  • 57
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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  • 58
    Publication Date: 2011-08-16
    Description: A previous theory which did not require a usual closure assumption required three or more initial spectra. By allowing a simple physical assumption (a modification of Kovasznay's (1948) hypothesis), the required number of spectra is reduced to two. Agreement with experiment is good.
    Keywords: FLUID MECHANICS
    Type: Physics of Fluids; 17; Mar. 197
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  • 59
    Publication Date: 2011-08-16
    Description: The Skylab S-193 altimeter experiment utilizes a 10- and 100-ns pulse length, 13.9-GHz earth-pointed radar system to obtain earth-surface backscatter measurements from the Skylab spacecraft. Objectives of the experiment are to obtain precision measurements of surface profile for uses in geodesy, oceanography, and earth physics, and to measure radar-signal characteristics from an earth-orbit geometry to provide design information for future radar remote-sensors. The technical approach is that of measuring the power impulse response of the scattering surface. The hardware is designed to operate in five modes: waveform or impulse-response measurement and altitude determination; radar cross-section experiment; signal correlation experiment; 10-nsec pulse-compression evaluation; and nadir-seeker experiment.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE; vol. 62
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  • 60
    Publication Date: 2011-08-16
    Description: The possibility of applying the principles of holography and optical data processing in the control of self-propelled space vehicles is considered. Various methods of controlling space vehicles are described: (1) by the results of comparing the image with the standard hologram; (2) by holographic images transmitted over moon earth communications channels; and (3) on the basis of using autotelevision cameras with a three dimensional screen. Procedures are presented for obtaining the standard holograms. The structural organization of the microprogrammed automaton controlling the movement of the space vehicle is also presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 111-142
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  • 61
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    Publication Date: 2011-08-16
    Description: Methods for predicting erosion resulting from repeated localized impulsive loadings, such a impacts from droplets or in cavitation flow from microjets and bubbles, are examined. The parameters which determine the adequacy of a component to resist the loads put upon it are identified. The development of erosion rate models is discussed. The expected accuracy of the prediction and the sources of error are analyzed.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failure; p 107-114
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  • 62
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: To study cavitation inception in polymer solutions, a blow-down water tunnel with short running times was used. Tests were made using 1/4 and 1/2 inch diameter models of hemispherical-nose cylinders. To accurately detect the inception of cavitation, a reliable technique was developed using a continuously operating He-Ne gas laser. The laser beam was adjusted to grazing incidence with the model at the minimum pressure point where cavitation inception was to be expected. A sensitive photocell was placed at ninety degrees to detect the beam. As incipient cavitation occurred, the bubbles caused scattering of the laser beam which was picked up by the photocell. Static pressure near the model in the working section of the tunnel was measured using a solid-state pressure pick-up. The signals from the photocell and the pressure pick-up were recorded on an oscillograph. Velocity field visualization was achieved using one microsecond duration light pulses scattered by small polystryrene latex spheres in the flow.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 100-106
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  • 63
    Publication Date: 2011-08-16
    Description: The effects of cavitating flow on the polymeric additives used in functional fluids are described. A comparison of thermal and mechanical stability tests for these polymer solutions show distinct differences in the machanism of the polymer degradation. The thermal degradation tests appear to cause an unzippering or depolymerization type of reaction in which there is no particular selectivity based on molecular weight. The mechanical degradation of these fluids appears to be based on molecular weight. Measurements of molecular weight distributions during mechanical degradation show that for a given level of intensity only molecules above a certain minimum size are degraded. The effects of ultrasonic radiation on polymer degradation are reported. Tests were conducted to demonstrate the mechanism of mechanical polymer degradiation in an orifice. A more severe test than the orifice test in which two tapered roller bearings loaded against each other produce the mechanical breakdown is discussed.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 88-99
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  • 64
    Publication Date: 2011-08-16
    Description: A numerical analysis of the pressure distribution of a lubricant in contact with a rough surface was conducted. The magnitude of the pressures was determined by their root mean square value for the contact of two dimensional cylinders. The pressure was found to vary in the following manner: (1) the location in the contact, (2) the spectrum or frequency content of the surface roughness, (3) the mean plateau film thickness, and (4) the root mean square value of the surface roughness. Mathematical models are developed to show the relationships of the parameters.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 62-73
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  • 65
    Publication Date: 2011-08-16
    Description: The effects of cavitation flow on piston type, positive displacement, hydraulic pumps are discussed. The operating principles of the pump and the components which are most subject to erosion effects are described. The mechanisms of cavitation phenomena are identified from photographic records. Curves are developed to show the solubility of air in water, oil-water emulsion, and industrial hydraulic oil.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 48-53
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  • 66
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: The problem of failures caused by cavitation erosion are discussed. The concepts of intensity of erosion, erosion strength, and the time dependence of erosion rate are analyzed. The relation of these parameters to system variables such as pressure and velocity, and to the properties of materials are investigated. Using several examples of actual cavitation erosion, methods of prevention and their limitations are examined.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 39-47
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  • 67
    Publication Date: 2011-08-16
    Description: Theories of cavitation damage mechanisms are discussed. Photographic evidence has shown that the actual collapse of bubbles near a symmetry-destroying feature such as a nearby wall results in a toroidal-like collapse, with the final generation of a liquid microjet oriented toward the wall. Numerical analyses indicate that the shock wave intensity emitted during collapse is not likely to be strong enough to be damaging to most materials. It has been determined that actual damage is usually a result of a combination of impact effect of the microjet and the shock wave pressures generated by bubble rebounds.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 31-35
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  • 68
    Publication Date: 2011-08-16
    Description: Methods for determining the correlations of erosion resistance and mechanical properties of materials are discussed. The most common method of testing cavitation erosion resistance of materials is the vibratory cavitation probe. The instrument and its operation are described. The use of the whirling arm device is considered as a second method. Metallographic investigations of the earliest stages of cavitation erosion damage of metallic materials was conducted. The materials show plastic deformation occurring during the incubation period and increasing until cracks form and metal fragments are lost. The parameters of the work done to cause material fractures are identified. The reactions obtained with specific materials are reported.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 23-30
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  • 69
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: The dependence of erosion rates on the ambient temperature of water is discussed. The assumption that the gas inside the bubble is compressed adiabatically during collapse gives better agreement with experiments than the assumption that the gas is isothermally compressed. Acoustic impedance is an important liquid parameter that governs the erosion intensity in vibratory devices. The investigation reveals that the major physical properties of liquids governing the intensity of erosion include density, sound speed, surface tension, vapor pressure, gas content, and nuclei distribution.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 13-22
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  • 70
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: The role of cavitation in mechanical failure is discussed. Some of the most common types of material damage associated with the presence of cavitation are surface material removal, delamination and structural vibration. This occurs in external flows such as on propellers, hydrofoils, and high speed non-lifting surfaces. In internal flows, pipe bends, inlets, constructions, pumps and turbines are typical. Nominally nonflowing liquids are also susceptible in, for example, strong acoustic fields and high energy particle detectors. For flowing systems, Bernoulli's equation shows how a local pressure is reduced as the fluid's velocity is increased. At sufficiently high velocities, a tension can actually develop and this has, in fact, been demonstrated experimentally. Once the pressure is reduced below the fluid vapor pressure a vapor cavity can be nucleated. Various aspects of this process are simply shown by considering the flow over a lifting surface.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 3-12
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  • 71
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    Publication Date: 2011-08-16
    Description: The design and construction of an ultrasonic frequency electronic power generator are discussed. The principle design elements of the generator are illustrated. The generator provides an inductive load with an output power of two kilowatts and a variable output frequency in the fifteen to thirty KiloHertz range. The method of conducting the tests and the results obtained with selected materials are analyzed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 33-39
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  • 72
    Publication Date: 2011-08-16
    Description: The development of methods for the nondestructive study of concrete structures is discussed. The nondestructive test procedure is based on the method of ultrasonic pulse transmission through the material. The measurements indicate that the elastic properties of concrete or other heterogeneous materials are a function of the rate of ultrasonic propagation. Diagrams of the test equipment are provided. Mathematical models are included to support the theoretical aspects.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 27-32
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  • 73
    Publication Date: 2011-08-16
    Description: A method of studying thin plate vibrations with the aid of a laser beam is discussed. Through a suitable combination of time-average holographic interferometry, real-time holographic interferometry, and heterodyne optical detection, it is possible to obtain complete information on the vibration parameters of modes, amplitudes, frequencies, and phases. The method has the advantage of three dimensional global observation, noncontact, and high precision measurements.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 7-14
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  • 74
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    Publication Date: 2011-08-16
    Description: The development of a system of ultrasonic holography is discussed. The limitations of the acousto-optical transformers, the scanning method, and the Pohlman cell are analyzed. The application of the free liquid surface deformation method is emphasized. The test equipment required for the liquid surface deformation method is described. An illustration of a typical test installation is provided.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 1-6
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  • 75
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    Publication Date: 2011-08-16
    Description: Holography with standing surface plasma waves, where both reference and object beams propagate in opposite directions, has been investigated using an Al reflection grating coated with evaporated As2S3 layers. The image, which appears only for p-polarization and at certain critical angles, is enhanced by the Lippman-Bragg effect and by an increase in intensity over ordinary holography approximately equal to the absolute value of the real part of the dielectric constant for Al. Also considered is holography with object light alone in photoresist layers, using the beam-splitting properties of the grating.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optics Communications; 12; Dec. 197
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  • 76
    Publication Date: 2011-08-16
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Vacuum Science and Technology; 11; Sept
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  • 77
    Publication Date: 2011-08-16
    Description: Comparison of lidar and in situ measurements of stratospheric aerosol profiles obtained by backscattered ruby laser light and by direct in situ sampling over Laramie, Wyoming, on two nights in mid-September 1972. The lidar backscattering and the particle number density profiles correlated well. Based on these initial comparative experiments, the ground-based lidar coupled with temperature soundings appears to be a possible method for determining the relative aerosol profile under given stratospheric loading conditions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Oct. 197
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  • 78
    Publication Date: 2011-08-16
    Description: A technique is described for use in the fabrication of glancing incidence telescopes which operate at large grazing angles (i.e., 8 to 15 degrees). Precision conic section plunge laps are used in a controlled grinding procedure to initially generate imaging surfaces which have a minimum of subsurface damage. A numerically controlled Moore Number 3 Measuring Machine is used throughout the fabrication procedure. Surface geometry accuracies on the order of one-tenth micron have been achieved.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering; 13; Mar
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  • 79
    Publication Date: 2012-05-22
    Description: The development of flight test instrumentation systems based on specific requirements for the flight tests is discussed. The factors which influence the instrumentation system design are described. The use of a measurements list as a device for determining flight test requirements is explained. A block diagram of a typical flight test instrumentation system is provided. The effects of factors such as cost, schedule, personnel, accuracy, environmental qualifications, and reliability are analyzed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AGARD AGARD Flight Test Instrumentation Ser., Vol. 1; 9 p
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  • 80
    Publication Date: 2011-08-16
    Description: A simple method for detecting bacteria, based on the time of hydrogen evolution, was developed and tested against various members of the Enterobacteriaceae group. The test system consisted of (1) two electrodes, platinum and a reference electrode, (2) a buffer amplifier, and (3) a strip-chart recorder. Hydrogen evolution was measured by an increase in voltage in the negative (cathodic) direction. A linear relationship was established between inoculum size and the time hydrogen was detected (lag period). Lag times ranged from 1 h for 1 million cells/ml to 7 h for 1 cell/ml. For each 10-fold decrease in inoculum, length of the lag period increased 60 to 70 min. Based on the linear relationship between inoculum and lag period, these results indicate the potential application of the hydrogen-sensing method for rapidly detecting coliforms and other gas-producing microorganisms in a variety of clinical, food, and other samples.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Microbiology; 27; May 1974
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  • 81
    Publication Date: 2011-08-16
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Oct. 197
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  • 82
    Publication Date: 2011-08-16
    Description: The feasibility of performing Raman and laser velocimeter measurements simultaneously is demonstrated, and it is shown that the background radiation associated with the Mie scattering and large particulate concentrations does not saturate or distort the relatively weak rotational Raman signals. Under stringent conditions of low static gas densities and large particulate concentrations, Raman density and temperature measurements agree to within plus or minus 5% of the calculated values.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal; 12; Oct. 197
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  • 83
    Publication Date: 2011-08-16
    Description: The behavior of the unsteady laminar boundary layer induced by the incident shock wave passing over a flat plate mounted in a shock tube has been experimentally studied for shock speeds ranging from 2.35 to 7.34 km/sec by measuring unsteady heat transfer rates to the plate using thin-film heat-flux gages. Theoretical heat-transfer rates were predicted from analytical solutions in the literature which describe the unsteady flat plate boundary layer development for equilibrium real-gas flows. Experimental results obtained for both air and nitrogen were found to be in good agreement with the theoretical predictions.
    Keywords: FLUID MECHANICS
    Type: Physics of Fluids; 17; May 1974
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  • 84
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    Publication Date: 2011-08-16
    Description: The present work describes a scheme for a noise suppression system to be used with an afocal coherent optical data processor. The noise averaging scheme is based on the simple principle of moving input and output film planes together during exposure; the noise pattern remains stationary while the desired (filtered) image moves through it. The noise suppression system consists of a drive motor, right-angle gear box, reversing gear assemblage, right-angle gear drive, and micrometer adjusting translation tables. The device was tested by using a Sayce target containing fundamental spatial frequencies from 5 lines/mm to 100 lines/mm as the input signal. The output was photographed on Pan-X 35-mm film with and without the noise suppression system in operation. Microdensitometer scans of the exposed output film show that without noise averaging, resolution is good to about 80 lines/mm, while with noise averaging, it is good to about 35 lines/mm. A brief analysis of errors in the mechanical parts of the system reponsible for the upper limit of resolution is presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Oct. 197
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  • 85
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    Publication Date: 2011-08-16
    Description: An X-band radar capable of continuously variable transmitted pulse durations down to 1 nsec is being flown to investigate the interaction of radar altimeter signals with the sea surface. There is good agreement between the observed radar altimeter leading edge rise time for a 1-nsec transmitted pulse and the rise time predicted from the radar parameters and the sea state determined by a laser profilometer. Using a threshold tracker on 29-pulse averages for a transmitted pulse of 24 nsec, it was found that the range noise varied linearly with the power level of the threshold over a considerable range. The altimeter range quantization was 9.35 cm, and a minimum range noise of 3.9 cm was obtained. A comparison of pulse-to-pulse correlation observed in the radar data with that predicted by a Monte Carlo simulation is used to obtain a measure of sea surface scatterer motion.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Radio Science; 9; Aug
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  • 86
    Publication Date: 2011-08-16
    Description: The device described consists of two distinct parts: (1) The sound pickup system consisting of the wide-frequency band condenser microphone which contains in the same assembly the frequency-modulated oscillator and the output stage. Being transistorized and small, this system can be easily moved, so that sounds can be picked up even in places that are difficult to reach with larger devices. (2) The receiving and recording part is separate and can be at a great distance from the sound pickup system. This part contains a 72 MHz input stage, a frequency changer that gives an intermediate frequency of 30 MHz and a multichannel analyzer coupled to an oscilloscope and a recorder.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 67-70
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  • 87
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-16
    Description: The characteristics of an ultrasonic generator with magnetostrictive amplifiers are described. The generator was designed to supply an output power of about 400 watts at a consumption of about 1 kilowatt. The generator produces sound waves in the frequency range of 18 to 30 KHz. The circuit design is described and examples of the construction are illustrated. The generator is used to study different industrial processes such as the effect of ultrasonic radiation of the emulsification of liquids, the dispersion of solids, and ultrasonic filtration.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 40-52
    Format: text
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  • 88
    Publication Date: 2011-08-16
    Description: A commercial quadrupole mass spectrometer (residual gas analyzer, RGA) system has been modified to operate at large separations of its electronics console and sensing head. The methods implemented have made practical applications, as well as operation, of such a system possible for the first time. This advance was stimulated by a need for placing sensors at remote (45 or 60 m) chamber locations for space simulation testing of orbital flight spacecraft. Emphasis is placed on instrument functional requirements and describing the hardware changes and adjustment techniques necessary to assure operation at the extended cable lengths.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Spectroscopy; 28; Mar
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  • 89
    Publication Date: 2011-08-16
    Description: Description of a new method of writing the conservation equations of gasdynamics in curvilinear coordinates which eliminates undifferentiated terms. It is thus possible to readily apply difference schemes derived for Cartesian coordinates which conserve mass, momentum, and energy in the total flow field. The method is derived for orthogonal coordinates, and then extended to cover the most general class of coordinate transformations, using general tensor analysis. Several special features of the equations are discussed.
    Keywords: FLUID MECHANICS
    Type: Journal of Computational Physics; 14; Feb. 197
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  • 90
    Publication Date: 2011-08-16
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; May 1974
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  • 91
    Publication Date: 2011-08-16
    Description: A laser has been combined with a mass spectrometer in a new configuration developed for studies of high-temperature materials. A vacuum-lock, solid-sample inlet is mounted at one end of a cylindrical, high-vacuum chamber one meter in length with a nude ion-source, time-of-flight mass spectrometer at the opposite end. The samples are positioned along the axis of the chamber at distances up to one meter from the ion source, and their surfaces are vaporized by a pulsed laser beam entering via windows on one side of the chamber. The instrumentation along with its capabilities is described, and results from laser-induced vaporization of several graphites are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Journal of Mass Spectrometry and Ion Physics; 13; 1974
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  • 92
    Publication Date: 2011-08-16
    Description: A two-channel spectrometer was calibrated in the wavelength region 1200-3400 A and flown on an Aerobee rocket to observe the stars alpha Lyr, eta UMa, and zeta Oph. Standard tungsten lamps provided the absolute calibration down to 2250 A, and a photodiode calibrated by the National Bureau of Standards was the reference at shorter wavelengths. The molecular branching-ratio technique of relative calibration using the gases CO, NO, and N2 was a check on the absolute calibration. The flux from eta UMa agrees with the prediction of a hydrogen line blanketed model atmosphere within 10% between 1700 and 3400 A and within 4% over most of this wavelength region.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Astronomy and Astrophysics; 30; 1, Ja; Jan. 197
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  • 93
    Publication Date: 2011-08-16
    Description: The purpose of the present note is to show that on a flat plate where both the wall temperature and mean wall pressure are constant, neither of the limitations of parallel flow or of unity for the turbulent Prandtl number are required in order for the Crocco solution to apply to the turbulent boundary-layer flow. It is shown herein that this result is subject to restrictions on the magnitude of pressure fluctuations. The same analysis is generalized to show that the compressible turbulent boundary layer on an isothermal swept flat plate is independent of the spanwise flow if the molecular Prandtl number is unity.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Feb. 197
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  • 94
    Publication Date: 2011-08-16
    Description: High-transmission, low-pass scatter filters for blocking at wavelengths from 3.5 to 50 microns and single-layer antireflection coatings for optical materials used in the 25- to 300-micron region of the spectrum are described. The application of both techniques to liquid-He-cooled filters permits the construction of efficient low-pass and medium-width bandpass filters for use throughout the far infrared.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics; 13; Feb. 197
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  • 95
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2012-05-22
    Description: The use of transducers in the measuring channels of flight test instrumentation systems is discussed. Emphasis is placed on transducers with an electrical output. The physical effects used for producing the electrical outputs are defined. Diagrams of the various types of transducers are included to show the operating principles.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AGARD AGARD Flight Test Instrumentation Ser., Vol. 1; 14 p
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  • 96
    Publication Date: 2016-06-07
    Description: Various methods presently used for the dissemination of time at several levels of precision are described along with future projects in the field. Different aspects of time coordination are reviewed and a list of future laboratories participating in a National Time Scale will be presented. A Brazilian Atomic Time Scale will be obtained from as many of these laboratories as possible. The problem of intercomparison between the Brazilian National Time Scale and the International one will be presented and probable solutions will be discussed. Needs related to the TV Line-10 method will be explained and comments will be made on the legal aspects of time dissemination throughout the country.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the Sixth Ann. Precise Time and Time Interval (PTTI) Planning Meeting; p 99-107
    Format: application/pdf
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  • 97
    Publication Date: 2016-06-07
    Description: The methods of synchronizing precision clocks will be reviewed placing particular attention to the simpler techniques, their accuracies, and the approximate cost of equipment. The more exotic methods of synchronization are discussed in lesser detail. The synchronization techniques that will be covered will include satellite dissemination, communication and navigation transmissions via VLF, LF, HF, UHF and microwave as well as commercial and armed forces television. Portable clock trips will also be discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the Sixth Ann. Precise Time and Time Interval (PTTI) Planning Meeting; p 29-37
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  • 98
    Publication Date: 2016-06-07
    Description: Between July 1973 and January 1974, three time transfer experiments using the Timation 2 satellite were conducted to measure time differences between the U.S. Naval Observatory and Australia. Statistical tests showed that the results are unaffected by the satellite's position with respect to the sunrise/sunset line or by its closest approach azimuth at the Australian station. Further tests revealed that forward predictions of time scale differences, based on the measurements, can be made with high confidence.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the Sixth Ann. Precise Time and Time Interval (PTTI) Planning Meeting; p 513-531
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  • 99
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2016-06-07
    Description: The basic time scales are presented: International Atomic Time, Universal Time, and Universal Time (Coordinated). These scales must be maintained in order to satisfy specific requirements. It is shown how they are obtained and made available at a very high level of precision.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the Sixth Ann. Precise Time and Time Interval (PTTI) Planning Meeting; p 17-26
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  • 100
    Publication Date: 2016-06-07
    Description: A treatment is given of relativistic clock synchronization effects due to the rotation of the earth. Unlike other approaches, the point of view of an earth fixed coordinate system is used which offers insight to many problems. An attempt is made to give the reader an intuitive grasp of the subject as well as to provide formulae for his use. Specific applications to global timekeeping, navigation, VLBI, relativistic clock experiments, and satellite clock synchronization are discussed. The question of whether atomic clocks are ideal clocks is also treated.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Its Proc. of the Sixth Ann. Precise Time and Time Interval (PTTI) Planning Meeting; p 395-424
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