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  • General Chemistry  (9,374)
  • INSTRUMENTATION AND PHOTOGRAPHY  (3,829)
  • Cell & Developmental Biology  (3,632)
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  • 1
    Publication Date: 2006-02-14
    Description: The use of laser holography for measuring the distortion of antennas under space simulation conditions is described. The subject is the so-called double exposure procedure which allows to measure the distortion in the order of 1 to 30/micrometers + or - 0.5 per hologramme of an area of 4 m diameter max. The method of holography takes into account the constraints of the space simulation facility. The test method, the test set up and the constraints by the space simulation facility are described. The results of the performed tests are presented and compared with the theoretical predictions. The test on the K-Band Antenna e.g., showed a distortion of approximately 140/micrometers + or - 5/micrometers measured during the cool down from -10 C to -120 C.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center 13th Space Simulation Conf.; p 309-319
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  • 2
    Publication Date: 2006-02-14
    Description: Conventional schemes for digitizing large volumes of photographic data are far too costly and time consuming to encourage the undertaking of the ambitious projects using traditional technology. There is a distinct need for fast digitizing systems such as could be derived from development of large format, optically multiplexed CCD systems designed to address these problems. The use of CCD chips for data handling and the capability of using polaroids in the optical path for reduced light scattering are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 419-427
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  • 3
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Parameters of the UK 1.2 meter Schmidt telescope are described. Plates taken with this instrument are in two categories, those for systematic sky surveys and those taken at the request of research users. A collaborative project with the European Southern Observatory was undertaken to obtain a two-color survey of the sky south of -20 deg declination to complement the Palomar survey. A near infrared survey of the Galactic Plane and the Megallanic Clouds is being done. The area south of -20 deg and the zone between 0 deg and -15 deg are also being surveyed. Pending a decision on survey parameters, all available A quality prism plates are being retained to form a basis for systematic survey. Nearly half the plates taken on a service basis for the UK astronomical community are to fulfill nonsurvey requests. Plates taken for surveys which are not of A grade quality are also made available for research purposes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 379-385
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  • 4
    Publication Date: 2006-02-14
    Description: Some software facilities used mainly for information retrieval and analysis at the Padova-Asiago Observatory are discussed. These facilities help guest and resident astronomers to make easier the preparation of plate measurements. The problems connected with the creation, use and management of a data base in a scientific (astronomical) environment are reviewed on the basis of the experience gathered during the last three years. The development plan of the user session environment and its possible applications in a computer network are briefly sketched.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 361-369
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  • 5
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    In:  CASI
    Publication Date: 2006-02-14
    Description: A 256 diode-array will be installed as detector on the ESO OPTRONICS S-3000 measuring machine in order to increase the acquisition rate. A high intensity LED will be used as light source in a pulse mode. The data will be stored on a random access mass storage device as density values for later education. The scanning time for a 30 cm x 30 cm plate with a step size of 10 micron will be less than 10 hours while the dynamic range of the data is expected to be 2.5 density units with an offset of at least 1 unit.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 317-328
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  • 6
    Publication Date: 2006-02-14
    Description: The design and performance of the automated photographic measuring facility at Cambridge is described. It consists of a precision laser scanning microdensitometer connected to a series of computers that process the data on-line. Plates up to 350 mm square can be measured. The microdensitometer samples the plate to 12 bit accuracy at a speed of 230,000 samples/second. The positional accuracy is better than a micron. Other features include platen rotation and automatic focus.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 277-288
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  • 7
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    In:  CASI
    Publication Date: 2006-02-14
    Description: The expected performance of the Minnesota automated dual-plate scanner (APS) is discussed with regard to photometry, position measurement accuracy, and ability to classify images. In addition, a fast algorithm for calculating image parameters is described.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 267-276
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  • 8
    Publication Date: 2006-02-14
    Description: Various aspects of the performance of the PDS 1010A microdensitometer are described. The primary points in an upgrade propsal for the unit are outlined. Photometric instabilities in the PDS are mentioned.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 129-134
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  • 9
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Minor modifications of electronic components in the PDS 1010A microdensitometer are discussed. The operational requirements and performance limitations of the PDS are noted. Replacement of the photomultiplier and front-end analog circuitry significantly improved the photometric performance of the PDS. The improvement in density repeatability is marked, and the permissible density slew speed is greatly increased.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 121-128
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  • 10
    Publication Date: 2006-02-14
    Description: High Altitude Observatory HAO microdensitometer undergoes monthly testing to assure its consistent performance. These tests check positional and photometric stability at the 10 micron aperture level. The HAO test procedure is designed to run without operator intervention following initial configuration of the microdensitometer for each subprocedure. Specialized test software is resident in the PDP 8. The operator selects the proper subprocedure by entering commands. Once computer control is established, it is not relinquished until the test is complete.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Astron. Microdensitometry Conf.; p 19-34
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  • 11
    Publication Date: 2006-02-14
    Description: A number of diagnostic tests are developed for the Photometric Data System PDS 2020G microdensitometer to monitor its performance and to isolate various electromechanical problems. A number of tests which help to diagnose problems with the photometer, positional accuracy and data collection are described. The tests include: (1) scanning a razor blade edge to study the response of the photometer and zero point losses in the coordinate system, (2) scanning a long straight line to evaluate the drunkness of the stage motions, (3) scanning photometric step wedge calibrations to study the response of the photometer, and (4) measurement of a series of high signal to noise plates of the same region of the sky to evaluate the overall performance of the microdensitometer. A variety of electronic tests to isolate electromechanical problems are also performed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 3-18
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  • 12
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    In:  CASI
    Publication Date: 2006-02-14
    Description: The behavior of ruled and holographic gratings with various coatings after extended exposure to the space environments was examined. The coatings and differentiating between the influences of vacuum and solar illumination were examined. In the past, several ruled and holographic gratings with various coatings were successfully flown on rocket experiments. Future utilizations of such gratings are considered for the Space Telescope and for various Spacelab projects under development. The techniques which is used to replicate gratings can also be used to obtain a wide range of lightweight optical components, including sophisticated aspherical, highly polished mirrors.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 163-164
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  • 13
    Publication Date: 2006-02-14
    Description: Electro-optic holographic recording systems were developed. The spaceworthiness of electro-optic crystals for use in ultrahigh capacity space data storage and retrieval systems are examined. The crystals for this experiment are included with the various electro-optical components of LDEF experiment. The effects of long-duration exposure on active optical system components is investigated. The concept of data storage in an optical-phase holographic memory is illustrated.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 152-153
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  • 14
    Publication Date: 2006-02-14
    Description: The specific scientific objectives of this experiment are to measure the spatial distribution, size, velocity, radiance, and composition of microparticles in near-Earth space. The technological objectives are to measure erosion rates resulting from microparticle impacts and to evaluate thin-foil meteor 'bumpers'. The combinations of sensitivity and reliability in this experiment will provide up to 1000 impacts per month for laboratory analysis and will extend current sensitivity limits by 5 orders of magnitude in mass.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 117-120
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  • 15
    Publication Date: 2006-02-14
    Description: One of the principal advantages of electrography when compared to photography is the nearly linear relationship between source intensity versus resulting image density. This property allows for simplified and more accurate photometric calibration and permits a certain degree of extrapolation of the calibration to beyond the limits of the faintest photoelectric standard on an exposure. The desires to extract quantitative photometric information from electrographic (or photographic) negatives and to convert this information into a digital format for computer analysis or enhancement led to the widespread use of scanning microdensitometers to perform this A-to-D conversion. Therefore it is of vital importance to understand and, if practical, to avoid any nonlinearities which may be introduced during microdensitometry of electrographic emulsions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 429-431
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  • 16
    Publication Date: 2006-02-14
    Description: The scanning of a direct plate with the automatic plate measuring machine which results in the automated selection and description of images is described. The selection of QSO candidates based on color-color diagrams constructed from the APM image data and the analysis of APM raster data for QSOs selected visually from objective prism plates are also discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 417-418
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  • 17
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    In:  CASI
    Publication Date: 2006-02-14
    Description: The fundamental limitations of microdensitometers are reviewed and the design of a high microdensitometer described. The system will digitize to 16 bits in transmission at a speed of 100 kHz using a laser beam moving over the emulsion. Other features are automatic platen rotation and autofocus. The cost will be of order $200,000.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 333-341
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  • 18
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    In:  CASI
    Publication Date: 2006-02-14
    Description: A new photographic measuring machine is under construction at the Paris Observatory. The amount of transmitted light is measured by a linear array of 1024 photodiodes. Carriage control, data acquisition and on line processing are performed by microprocessors, a S.E.L. 32/27 computer, and an AP 120-B Array Processor. It is expected that a Schmidt telescope plate of size 360 mm square will be scanned in one hour with pixel size of ten microns.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 329-332
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  • 19
    Publication Date: 2006-02-14
    Description: A diode-array based image digitizer manufactured by the Eikonix Corp. was tested to see if it can be adapted to the exacting requirements of astronomical densitometry. As the device is presently configured, a dynamic range of 400:1 can be achieved routinely, with a positional accuracy of 2 microns or better. An area of 2048 X 2048 pixels can be scanned in about 5 minutes. Preliminary tests indicate that several relatively simple enhancements can improve both the photometric and the positional accuracy of the device.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 307-315
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  • 20
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Motivations for construction of a next generation microdensitometer (NGM) are presented and their effect on the NGM design is discussed. A prototype of such an engine has been constructed at KPNO. Its design and performance is reviewed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 291-305
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  • 21
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    In:  CASI
    Publication Date: 2006-02-14
    Description: The motivations for constructing a special purpose built microdensitometer are explored. The salient points of some of the microdensitometers are described and the advantages and disadvantages of the system in comparison to a PDS machine are outlined. The principal gain is in speed though at the expense of loss in dynamic range. The effects on the astronomical results are demonstrated. The astronomical results already obtained with these machines and from ongoing projects are described. It is shown that there is a large class of important astronomical problems which can be tackled by these machines but which are not feasibile on the PDS because of the speed of the machine.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 209-228
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  • 22
    Publication Date: 2006-02-14
    Description: The necessity to incorporate several hardware changes to optimize the Yale PDS 2020G microdensitometer for photometric and astrometric research are discussed. The properties of a new high speed photometer and a positional calibration system are described. The new photometer incorporates a high speed logarithmic analog to digital converter with more than 10 times the resolution of the former system and a cycle time of approximately 50 usec. The positional calibration system monitors the drunkenness of the stages with respect to fixed index lines and enables the correction of the +/- 5 micro stage errors to an accuracy of better than 1 micro.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 151-161
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  • 23
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    In:  CASI
    Publication Date: 2006-02-14
    Description: The astrometric and photometric performance of the PDS 1010A microdensitometer are discussed, including the tests used for checking it. The instrument was shown to satisfy operational requirements for photometric measurements of astronomical plates with respect to dynamic range and stability.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 89-95
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  • 24
    Publication Date: 2006-02-14
    Description: The results of several parametric studies carried out on the Marshall Space Flight Center (MSFC) Photometric Data System PDS-10 microdensitometer are summarized for the purposes of documenting the operation and limitations of the system for inhouse research and to provide a bench mark for comparison with other microdensitometers. The results are grouped into four general areas. These are: (1) system overall stability to drift, (2) photometric linearity and noise, (3) reproducibility, and (4) scanning performance. Test data taken in order to evaluate the interdependency of scan speed, noise and position are included. Shown also are results of tests for system stability, reproducibility, stray light and PMT settling time.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Marshall Space Flight Center Astron. Microdensitometry Conf.; p 71-88
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  • 25
    Publication Date: 2006-02-14
    Description: The performance of densitometers used for photometric data reduction of high dynamic range electrographic plate material is analyzed. Densitometer repeatability is tested by comparing two scans of one plate. Internal densitometer errors are examined by constructing histograms of digitized densities and finding inoperative bits and differential nonlinearity in the analog to digital converter. Such problems appear common to the four densitometers used in this investigation and introduce systematic algorithm dependent errors in the results. Strategies to improve densitometer performance are suggested.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 45-58
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  • 26
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Various perturbations which occurred during the operation of a PDS 2020 GM microdensitometer are reviewed. The effects of elevated temperature, vibration, transient electrical noise, and photometric perturbations are briefly discussed. Sample astronomical results from the PDS 2020 GM unit are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 97-106
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  • 27
    Publication Date: 2006-02-14
    Description: Digitizing flatfield images produces conditions in the Photometric Data System PDS which cause the measured density to drift by as much as .1 DN during a 10 minute interval. The drift occurs when the PDS, set up in equilibrium at fog level, subsequently scans a reasonably dense region for periods of longer than a few minutes. The drift is manifested primarily as a positive shift in density that is approximately the same for all densities. If the fog level is assumed to be in fact constant and is monitored during scans of flat fields, the PDS drift may be removed by subtracting the difference between the observed fog level and its assumed constant value for each pixel. This function is then smoothed and subtracted, as a function of scan line, from the measured density. The fog level is then adjusted to a standard value by adding a constant. The result is a flattened scan with PDS drift removed to the accuracy within which the fog level drift matches the drift at other levels.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Astron. Microdensitometry Conf.; p 59-69
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  • 28
    Publication Date: 2006-02-14
    Description: The photometric and positional accuracy of a microdensitometer is examined. A calibrating plate with different density areas available is used to determine photometric accuracy. Position accuracy is evaluated by multiple scans of sharp edges and analyzed statistically.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 35-43
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  • 29
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    In:  CASI
    Publication Date: 2006-02-14
    Description: Many of the passive experiments flying on LDEF will be significantly enhanced if data are available postflight to indicate the temperature time histories of test materials and other specimens exposed in the experiments. The baseline LDEF approach was to provide postflight calculated temperature histories of experiment boundaries and solar flux data for the mission, which can in turn be used by each investigator to calculate the temperature time histories for critical experiment components. Without in-flight temperature measurements, a substantial uncertainty will exist in the calculated temperatures. The data measured by the themal measurement system (THERM) will significantly improve postflight knowledge of temperatures experienced by LDEF experiments. The THERM data will also be valuable in validating the LDEF thermal design concept and in providing better design data for experimenters on future LDEF missions. The objectives of this experiment are to determine the history of the interior average temperatures of the LDEF for the total orbital mission and to measure the temperatures of selected components and thermal boundary conditions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Long Duration Exposure Facility (LDEF); p 78-81
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  • 30
    Publication Date: 2011-08-18
    Description: Previously cited in issue 5, p. 642, Accession no. A83-16486
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal (ISSN 0001-1452); 22; 1115-112
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  • 31
    Publication Date: 2011-08-18
    Description: The design of a high spectral resolution, lambda/delta lambda being approximately 1200 IR, sounder capable of increasing the vertical resolution of atmospheric temperature profiles and achieving a rms accuracy of approximately 1.5 K is discussed. This sounder permits improved determination of meteorological parameters on cloudiness, surface temperature, and air-surface interactions. A set of channels from the high J lines in the R branch of the 4.3-micron CO2 band complemented by a larger set of window, humidity, and temperature channels in the 3.7-, 6.3-, 9-, and 15-micron regions is used. Design and simulation studies show that such a sounder is within the present state of the art.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 979-989
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  • 32
    Publication Date: 2011-08-18
    Description: This paper presents the conceptual design of an instrument, called the solar disk sextant, to be used in space to measure the shape and the size of the sun and their variations. The instrumental parameters required to produce sufficient sensitivity to address the problems of solar oblateness, solar pulsations, and global size changes of climatic importance are given.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1235-123
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  • 33
    Publication Date: 2011-08-18
    Description: Previously cited in issue 05, p. 643, Accession no. A83-16685
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal (ISSN 0001-1452); 22; 557-559
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  • 34
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    Publication Date: 2011-08-18
    Description: A simple and inexpensive thermal diffusivity apparatus is described for measurement up to 1600 K. The novel features of apparatus include a light pipe, a long furnace, and a differential thermocouple. A low heat-load sample holder for clamping the sample in a vertical position is also described. The results of measurements on AXM-5Q graphite are reported.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 55; 235-237
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  • 35
    Publication Date: 2011-08-19
    Description: A wave sensor, consisting of parallel, evenly spaced capacitance wires, whose output is the sum of the water surface deflections at the wires, has been built and tested in a wave tank. The probe output simulates Bragg scattering of electromagnetic waves from a water surface with waves; it can be used to simulate electromagnetic probing of the sea surface by radar. The study establishes that the wave probe, called the 'Harp' for short, will simulate Bragg scattering and that it can also be used to study nonlinear wave processes.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Atmospheric and Oceanic Technology (ISSN 0739-0572); 1; 358-371
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  • 36
    Publication Date: 2011-08-19
    Description: The standard balloon-borne radiosonde employed for synoptic meteorology provides vertical profiles of temperature, pressure, and humidity as a function of elapsed time. These parameters are used in the hypsometric equation to calculate the geopotential altitude at each sampling point during the balloon's flight. It is important that the vertical location information be accurate. The present investigation was conducted with the objective to evaluate the altitude determination accuracy of the standard radiosonde throughout the entire balloon profile. The tests included two other commercially available pressure sensors to see if they could provide improved accuracy in the stratosphere. The pressure-measuring performance of standard baroswitches, premium baroswitches, and hypsometers in balloon-borne sondes was correlated with tracking radars. It was found that the standard and premium baroswitches perform well up to about 25 km altitude, while hypsometers provide more reliable data above 25 km.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Atmospheric and Oceanic Technology (ISSN 0739-0572); 1; 321-327
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  • 37
    Publication Date: 2011-08-19
    Description: This paper presents an algorithm for azimuth correlation of synthetic aperture radar (SAR) data with extraordinarily large-range migration which cannot be accommodated by the existing frequency domain interpolation approach used in current Seasat SAR processing. A mathematical model is provided for the SAR range-correlated point-target response both in the spatial and frequency domains. A simple and efficient processing algorithm derived from the exact two-dimensional correlation algorithm is given. This algorithm enables azimuth correlation by two cascaded one-dimensional correlation steps. The first step is to transform the range-correlated SAR data into the frequency domain in azimuth, followed by a newly developed range convolution filter to correct the range-dispersed spectrum of the range-correlated point-target response (RCPTR). The second step is the frequency-domain range migration correction approach for the azimuth compression. Simulation results provided here indicate that this processing algorithm yields a satisfactory compressed impulse response for SAR data with large-range migration whereas previous methods were subject to a broadening of the impulse response along range.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-22; 592-597
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  • 38
    Publication Date: 2011-08-18
    Description: The laser-induced fluorescence (LIF) of green plants was evaluated as a means of remotely detecting plant stress and determining plant type. Corn and soybeans were used as representatives of monocots and dicots, respectively, in these studies. The fluorescence spectra of several plant pigments was excited with a nitrogen laser emitting at 337 nm. Intact leaves from corn and soybeans also fluoresced using the nitrogen laser. The two plant species exhibited fluorescence spectra which had three maxima in common at 440, 690, and 740 nm. However, the relative intensities of these maxima were distinctly different for the two species. Soybeans had an additional slight maxima at 525 nm. Potassium deficiency in corn caused an increase in fluorescence at 690 and 740 nm. Simulated water stress in soybeans resulted in increased fluorescence at 440, 525, 690, and 740 nm. The inhibition of photosynthesis in soybeans by 3-(3-4-dichlorophenyl)-1-1-dimethyl urea (DCMU) gave incresed fluorescence primarily at 690 and 740 nm. Chlorosis as occurring in senescent soybean leaves caused a decrease in fluorescence at 690 and 740 nm. These studies indicate that LIF measurements of plants offer the potential for remotely detecting certain types of stress condition and also for differentiating plant species.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 134-142
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  • 39
    Publication Date: 2011-08-19
    Description: The balloon-borne microwave limb sounder (BMLS) measures atmospheric thermal emission from millimeter wavelength spectral lines to determine vertical profiles of stratospheric species. The instrument flown to date operates at 205 GHz to measure ClO, O3, and H2O2. A 63 GHz radiometer will be added to test the technique for determining tangent point pressure from the MLS experiment on the upper atmosphere research satellite (UARS). Many additional species could also be measured by the BMLS. A radiometer at 270 GHz would provide measurements of HO2, NO2, HNO3, N2O, O-16O-18O-16, and HCN. With this addition, the BMLS can test the current theory of O3 photochemical balance in the upper stratosphere.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Quantitative Spectroscopy and Radiative Transfer (ISSN 0022-4073); 32; 407-433
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  • 40
    Publication Date: 2011-08-19
    Description: The present cryogenic blackbody reference, or 'cold load', for mm-wavelength radiation has an emissivity of more than 0.99 over a two-octave wavelength range and can be used as a calibrating standard for sensitive IR photometers. The transmittance spectrum obtained indicates that wave impedance and index do not vary significantly over the 80-360 GHz range.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: International Journal of Infrared and Millimeter Waves (ISSN 0195-9271); 5; 1507-151
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  • 41
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    Publication Date: 2011-08-19
    Description: This paper discusses the measurement and comparison of particle size and velocity measurements in sprays. The general nature of sprays and the development of standard, consistent research sprays are described. The instruments considered in this paper are: pulsed laser photography, holography, television, and cinematography; laser anemometry and interferometry using visibility, peak amplitude, and intensity ratioing; and laser diffraction. Calibration is by graticule, reticle, powders with known size distributions in liquid cells, monosize sprays, and, eventually, standard sprays. Statistical analyses including spatial and temporal long-time averaging as well as high-frequency response time histories with conditional sampling are examined. Previous attempts at comparing instruments, the making of simultaneous or consecutive measurements with similar types and different types of imaging, interferometric, and diffraction instruments are reviewed. A program of calibration and experiments for comparing and assessing different instruments is presented.
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  • 42
    Publication Date: 2011-08-19
    Description: Nearly shot-noise limited detection of OH using the technique of laser-induced fluorescence is reported. A LIDAR configuration is used to excite fluoresence in a large volume and a narrow-bandwidth interference filter provides spectral discrimination. This arrangement alleviates the effect of ozone interference and facilitates image processing at relatively close distances. The detection limit is determined mainly by the short-noise of the solar background. Ground-based measurements in Dearborn indicate a detection limit of better than 1 x 10 to the 6th power OH/cubic cm over a forty-minute acquisition period. Under favorable conditions, a comparable detection limit was also observed for airborne measurements.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 4076-408
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  • 43
    Publication Date: 2011-08-19
    Description: The response characteristics of laser diffraction particle sizing instruments were studied theoretically and experimentally. In particular, the extent of optical sample volume and the effects of receiving lens properties were investigated in detail. The experimental work was performed with a particle size analyzer using a calibration reticle containing a two-dimensional array of opaque circular disks on a glass substrate. The calibration slide simulated the forward-scattering characteristics of a Rosin-Rammler droplet size distribution. The reticle was analyzed with collection lenses of 63 mm, 100 mm, and 300 mm focal lengths using scattering inversion software that determined best-fit Rosin-Rammler size distribution parameters. The data differed from the predicted response for the reticle by about 10 percent. A set of calibration factor for the detector elements was determined that corrected for the nonideal response of the instrument. The response of the instrument was also measured as a function of reticle position, and the results confirmed a theoretical optical sample volume model presented here.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering (ISSN 0091-3286); 23; 610-619
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  • 44
    Publication Date: 2011-08-18
    Description: An analysis method for Fourier transform spectroscopy is summarized with applications to various types of distortion in atmospheric absorption spectra. This analysis method includes the fast Fourier transform method for simulating the interferometric spectrum and the nonlinear least-squares method for retrieving the information from a measured spectrum. It is shown that spectral distortions can be simulated quite well and that the correct information can be retrieved from a distorted spectrum by this analysis technique.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 2604-261
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  • 45
    Publication Date: 2011-08-18
    Description: Sampling generally causes the response of a digital imaging system to be locally shift-variant and not directly amenable to Modulation Transfer Function (MTF) analysis. However, this paper demonstrates that a meaningful system response can be calculated by averaging over an ensemble of point-source system inputs to yield an MTF which accounts for the combined effects of image formation, sampling, and image reconstruction. As an illustration, the MTF of the Landsat MSS system is analyzed to reveal an average effective instantaneous field of view which is significantly larger than the commonly accepted value, particularly in the along-track direction where undersampling contributes markedly to an MTF reduction and resultant increase in image blur.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 2572-258
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  • 46
    Publication Date: 2011-08-18
    Description: Tests have been made of a nondispersive spectroscopic X-ray detector which operates by measuring the temperature rise following absorption of a single photon. Thermal pulses from 6-keV X-rays have been observed, and the different amplitudes resulting from Mn K-alpha and K-beta events have been resolved. This device was assembled to make quantitative tests of theoretical calculations of the properties of such detectors, and its high heat capacity does not allow it to attain the very high resolution predicted for detectors made by more sophisticated, but still straightforward, techniques. Both the measured resolution of 270-eV full width at half maximum and the absolute amplitude of the response are consistent with predictions. Nonthermal effects in the thermistor limit the precision of this comparison to about 30 percent.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Physics (ISSN 0021-8979); 56; 1263-126
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  • 47
    Publication Date: 2011-08-18
    Description: Sensitive thermal detectors should be useful for measuring very small energy pulses, such as those produced by the absorption of X-ray photons. The measurement uncertainty can be very small, making the technique promising for high resolution nondispersive X-ray spectroscopy. The limits to the energy resolution of such thermal detectors are derived and used to find the resolution to be expected for a detector suitable for X-ray spectroscopy in the 100 eV to 10,000 eV range. If there is no noise in the thermalization of the X-ray, resolution better than 1 eV full width at half maximum is possible for detectors operating at 0.1 K. Energy loss in the conversion of the photon energy to heat is a potential problem. The loss mechanisms may include emission of photons or electrons, or the trapping of energy in long lived metastable states. Fluctuations in the phonon spectrum could also limit the resolution if phonon relaxation times are very long. Conceptual solutions are given for each of these possible problems.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Applied Physics (ISSN 0021-8979); 56; 1257-126
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  • 48
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    Publication Date: 2011-08-18
    Description: A large-aperture interferometer was devised by adding a local-reference-beam-generating optical system to a schlieren system. Two versions of the interferometer are demonstrated, one employing 12.7 cm (5 in.) diameter schlieren optics, the other employing 30.48 cm (12 in.) diameter parabolic mirrors in an off-axis system. In the latter configuration a cylindrical lens is introduced near the light source to correct for astigmatism. A zone plate is a satisfactory decollimating element in the reference-beam arm of the interferometer. Attempts to increase the flux and uniformity of irradiance in the reference beam by using a diffuser are discussed. Previously announced in STAR as N83-13979
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1467-147
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  • 49
    Publication Date: 2011-08-18
    Description: A pulsed CO2 lidar was used to study statistical properties of signal returns from various rough surfaces at distances near 2 km. These included natural in situ topographic materials as well as man-made hard targets. Three lidar configurations were used: heterodyne detection with single temporal mode transmitter pulses, and direct detection with single and multiple temporal mode pulses. The significant differences in signal return statistics, due largely to speckle effects, are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1412-141
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  • 50
    Publication Date: 2011-08-18
    Description: This paper illustrates a method for calibrating seven-hole probes to measure local total and static pressures and relative flow angles of up to 70 degrees in subsonic compressible flows. The method of Latin Squares was used to statistically sample a large and otherwise unmanageable data set, thereby reducing to a minimum the number of data points required to construct a polynomial curve fit to the data. Calibration produces three-variable third order polynomials which permit all of the desired flow properties to be found explicitly from probe measured pressures. This method determines the flow angles to within 2 degrees and Mach number to within 0.04 with 95 percent certainty.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Experiments in Fluids (ISSN 0723-4864); 2; 2, 19; 95-103
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  • 51
    Publication Date: 2011-08-18
    Description: The stratospheric mixing ratio of nitric oxide at an altitude of 36 km has been measured using a balloon-borne tunable diode laser (TDL) instrument operating in the 5.2-micron wavelength region. Currently the instrument operates with two TDLs, and the capability exists to measure four stratospheric species simultaneously: NO, NO2, O3, and H2O. During the NO measurements reported here, the second TDL operating near 6.2 microns was used to monitor water vapor concentration in the vicinity of the gondola by observing the 1889.57 per cm line absorption in the reference channel path length (1 m).
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1140-114
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  • 52
    Publication Date: 2016-06-07
    Description: To facilitate the navigation of spacecraft to the outer planets, Jupiter and beyond, the JPL-NASA Deep Space Network (DSN) has implemented three ensembles of atomic clocks at widely separated locations. These clocks must be maintained, synchronized, to with a few parts in 10 to the 13th power of each other and, the entire group must be maintained, to a lesser degree, in synchronism with Coordinated Universal Time (UTC)NBS/USNO. Over the last 1 1/2 years the DSN has been using Global Positioning Satellites (GPS) and Very Long Baseline Interferometry (VLBI) technology to perform these critical Frequency and Time (F&T) synchronization tasks. A year of F&T synchronization data collected from the intercomparison of 3 sets of cesium and hydrogen maser driven clock ensembles through the use of GPS and VLBI techniques are covered. Also covered, are some of the problems met and limitations of these two techniques at their present level of technology.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the 16th Ann. Precise Time and Time Interval (PTTI) Appl. and Planning Meeting; p 447-465
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  • 53
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    Publication Date: 2016-06-07
    Description: The Fluids Experiment Apparatus FEA is a modular zero gravity chemistry/physics laboratory to support fundamental space processing research. It can be used to conduct basic and applied process or product experiments in general liquid chemistry, crystal growth, fluid mechanics, thermodynamics, and cell culturing. The various FEA subsystems are readily configured to perform a wide range of investigations.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Marshall Space Flight Center 2nd Symp. on Space Industrialization; p 333-341
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  • 54
    Publication Date: 2016-06-07
    Description: A demonstration test of burner liner strain measurements using resistance strain gages as well as a feasibility test of an optical speckle technique for strain measurement are presented. The strain gage results are reported. Ten Kanthal A-1 wire strain gages were used for low cycle fatigue strain measurements to 950 K and .002 apparent strain on a JT12D burner can in a high pressure (10 atmospheres) burner test. The procedure for use of the strain gages involved extensive precalibration and postcalibration to correct for cooling rate dependence, drift, and temperature effects. Results were repeatable within + or - .0002 to .0006 strain, with best results during fast decels from 950 K. The results agreed with analytical prediction based on an axisymmetric burner model, and results indicated a non-uniform circumferential distribution of axial strain, suggesting temperature streaking.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Lewis Research Center Turbine Engine Hot Section Technology, 1984; 16 p
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  • 55
    Publication Date: 2016-06-07
    Description: Laser anemometers are being developed for use in the turbine facilities at Lewis that are involved in the Turbine Engine Hot Section Technology Program. The status of the program is given along with some results accomplished since 1983.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Turbine Engine Hot Section Technology, 1984; 11 p
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  • 56
    Publication Date: 2016-06-07
    Description: The TRAK Systems' GOES Satellite Synchronized Time Code Generator is described. TRAK Systems has developed this timing instrument to supply improved accuracy over most existing GOES receiver clocks. A classical time code generator is integrated with a GOES receiver.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the 16th Ann. Precise Time and Time Interval (PTTI) Appl. and Planning Meeting; p 411-418
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  • 57
    Publication Date: 2016-06-07
    Description: Work on an innovative design for miniature rubidium frequency standards has reached the pre-production demonstration stage at Litton Guidance and Control Systems. Pre-production units were built and tested under contract to the Rome Air Development Center of the U.S. Air Force Systems Command. The units, which are designed for use in tactical military applications, feature fast warm-up, low power consumption, and vibration insensitivity. The output stability under vibration is maintained without the need for external shock-mounts. The design objectives and test results are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the 16th Ann. Precise Time and Time Interval (PTTI) Appl. and Planning Meeting; p 143-155
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  • 58
    Publication Date: 2016-06-07
    Description: The on-oribt operational performance of the frequency standards on the Global Positioning System (GPS) 1 to 10 NAVSTAR satellites are discussed. The history of the Rb frequency standards showing the improvements incorporated at various stages of the program and the corresponding results are presented. Also presented is the operational history of the NAVSTAR cesium frequency standards. The frequency standards configuration data presented covers the chronology of events from the concept validation satellites, NAVSTAR 1 to 10, starting in 1978 to the present, including the configurations of clocks to be used on the GPS Production Program. Data are presented showing the results of long-term laboratory testing of a production Rb frequency standard with the necessary data taken to calculate Delta F, drift, time error, and Allan variance.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center Proc. of the 16th Ann. Precise Time and Time Interval (PTTI) Appl. and Planning Meeting; p 127-141
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  • 59
    Publication Date: 2016-06-07
    Description: The mechanisms of the instrument pointing system (IPS) are described. Particular emphasis is placed on the actuators which are necessary for operating the IPS. The actuators are described as follows: (1) two linear actuators that clamp the gimbals down during ascent and descent; (2) two linear actuators that attach the payload to the IPS during the mission, and release it into the payload clamps; (3) one rotational actuator that opens and closes the payload clamps; and (4) three identical drive units that represent the three orthogonal gimbal axes and are the prime movers for pointing. Design features, manufacturing problems, test performance, and results are presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center The 18th Aerospace Mech. Symp.; p 15-28
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  • 60
    Publication Date: 2014-09-27
    Description: In order to utilize the quantitative accuracy built into the Thematic Mapper effectively, more attention must be paid to calibration before launch, changes of calibration before launch, changes of calibration with time in orbit, and atmospheric interference with the measurements, especially in the 450 to 520 nanometer band. Recent experience with the Coastal Zone Color Scanner (CZCS) program has led to procedures wherein Rayleigh correction factors can be generated utilizing simultaneous surface truth data that empirically give correct upwelled surface radiances. Instruments, such as the CZCS, have shown that calibration changes first, and to the largest degree, at the shorter wave lengths, with lesser changes as wave length increases. These techniques are utilized to calculate a Rayleigh correction factor that, together with geometric terms, will give an accurate correction for this portion of the atmospheric contribution to the signal.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Goddard Space Flight Center LANDSAT-4 Sci. Invest. Summ., Including Dec. 1983 Workshop Results, Vol. 2; p 20
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  • 61
    Publication Date: 2014-09-17
    Description: Relative spectral response data for the LANDSAT-4 and LANDSAT-4 backup multispectral scanner subsystems (MSS), the protoflight and flight models are presented and compared to similar data for the LANDSAT 1, 2 and 3 scanners. Channel (six channels per band) outputs for soil and soybean targets were simulated and compared within each band and between scanners. The principal differences between the spectral responses of the LANDSAT-4 scanners and previous scanners are discussed. The simulated LANDSAT-4 scanner outputs were 3 to 10 percent lower in the red band and 3 to 11 percent higher in the first near-IR band than previous scanners for the soybeans targets. The LANDSAT-4 scanners were generally more uniform from channel to channel within bands than previous scanners. In the upper-band edge of the red band of the protoflight scanner, one channel was markedly different (12 nm) from the rest. For a soybeans target, this nonuniformity resulted in a within-band difference of 6.2 percent in simulated outputs between channels.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: LANDSAT-4 Sci. Invest. Summ., Including Dec. 1983 Workshop Results, Vol. 2; p 73-75
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  • 62
    Publication Date: 2014-09-10
    Description: Eight water vapor radiometers (WVRs) were constructed as research and development tools to support the Advanced System Programs in the Deep Space Network and the Crustal Dynamics Project. These instruments are intended to operate at the stations of the Deep Space Network (DSN), various radio observatories, and obile facilities that participate in very long baseline interferometric (VLBI) experiments. It is expected that the WVRs will operate in a wide range of meteorological conditions. Several algorithms are discussed that are used to estimate the line-of-sight path delay due to water vapor and columnar liquid water rom the observed microwave brightness temperatures provided by the WVRs. In particular, systematic effects due to site and seasonal variations are examined. The accuracy of the estimation as indicated by a simulation calculation is approximately 0.3 cm for a noiseless WVR in clear and moderately cloudy weather. With a realistic noise model of WVR behavior, the inversion accuracy is approximately 0.6 cm.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Telecommun. and Data Acquisiton Rept.; p 12-26
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  • 63
    Publication Date: 2014-09-10
    Description: A water vapor radiometer is used to estimate the columnar content of atmospheric water vapor or equivalently the line-of-sight path delay due to water vapor. Two measurement channels are used in order to separate the effects of the liquid and vapor phases of water. The efficiency of the path delay or columnar vapor estimate is dependent on the choice of on-line frequency channel. Previous analysis of this problem has suggested frequencies from 20.3 to 21 GHz. The frequency that yields the minimum error in the inversion algorithm is shown here to be both site and season dependent. Hence, the concept of an optimum frequency must represent an averaging process over the entire range of meteorological conditions that is expected. For a range of sites and condition representing a cross section of the continental United States the optimum on-line frequency seems to be 20.6 GHz.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Telecommun. and Data Acquisition Rept.; p 1-11
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  • 64
    Publication Date: 2014-09-11
    Description: Time interval error (TIE) is the error of a clock at time t after it is synchronized and syntonized at time zero. Previous simulations of Flicker FM noise yielded a mean-square TIE proportional to sq t. It is shown that the order of growth is actually sq t log t. The earlier sq t result is explained and a modified version of the Barnes-Jarvis simulation algorithm is given.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Telecommun. and Data Acquisition Rept.; p 126-135
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  • 65
    Publication Date: 2014-09-11
    Description: The application of a sensitive hydrogen gas detector led to the observation of a significant increase in the efficiency of atom production of a magnetically enhanced dissociator. An increase of about 7000% in the production of atoms in the hyperfine state desired for maser operation is observed at certain values of the applied magnetic field. A preliminary test of the dissociator in the maser led to an observed increase of 6.18 dB in the maser power.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: The Telecommun. and Data Acquisition Rept.; p 19-23
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  • 66
    Publication Date: 2011-08-19
    Description: The development of solid-state sensor technology for multispectral linear array (MLA) instruments is described. A buttable four-spectral-band linear-format CCD and a buttable two-spectral band linear-format short-wave IR CCD have been designed, and first samples have been demonstrated. In addition, first-sample four-band interference filters have been fabricated, and hybrid packaging technology is being developed. Based on this development work, the design and construction of focal planes for a Shuttle sortie MLA instrument have begun. This work involves a visible and near-IR focal plane with 2048 pixels x 4 spectral bands and a short-wave IR focal plane with 1024 pixels x 2 spectral bands.
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  • 67
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    Publication Date: 2011-08-19
    Description: Current science projections for future earth-imaging instruments indicate the need for as many as 25 spectral bands, with bandwidths as narrow as 20 nanometers. The desire for a multiplicity of bands has led researchers to study various spectrally dispersive instrument designs as a means of providing the desired future capability. These instrument designs, however, are costly, complex, and of high technical risk. This paper describes a 'multiband selection device' containing several spectral filters that can be placed at the exit faces of a broadband multiport beam splitter and thereby provide a multiplicity of spectral bands with a high degree of spatial coregistration while utilizing state-of-the-art linear array detectors. Fabrication of the multiband selection device has been successfully accomplished, and the design and test results are described.
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  • 68
    Publication Date: 2011-08-19
    Description: A high precision Fizeau type, laser interferometer dilatometer system has been developed for low expansion composite materials. The strain resolution is about 1 microstrain. The system is automated to operate over a large temperature range and record data during the test in real time. A technique has been developed to reduce the fringe data in real time to length changes. The dilatometer system is described and thermal expansion measurements for several fiber-reinforced and particle filled composites are presented.
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  • 69
    Publication Date: 2011-08-19
    Description: The present paper provides a description of recent and continuing work related to the development of tracking systems possessing artificial intelligence. It is pointed out that artificial intelligence is being used to provide trackers with the abilities to sense environmental changes which can affect tracker performance, to optimize tracker performance in a changing environment, and to report on the accuracy and stability of the pointing data. The implementation of artificial intelligence in tracking systems is based on the use of adaptive algorithms which correct for tracking errors by applying polynomial corrections to raw tracking output data. The basic operation of a centroid tracking system is discussed, taking into account the limitations on accuracy and stability which exist in the absence of intelligence. Attention is given to the correction method and the implementation of artificial intelligence to improve tracking.
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  • 70
    Publication Date: 2011-08-19
    Description: An optical imager, called the Scanning Imaging Spectroradiometer (SIS), was built for NASA in the early 1970's. Later, the Solidstate Array Spectroradiometer (SAS) was developed on the basis on a substitution of a Charge Injection Device (CID) array for the vidicon of the SIS. The Advanced Solidstate Array Spectroradiometer (ASAS) represents an improvement of the SAS. ASAS is a solidstate multispectral optical imaging radiometer which is currently the most versatile instrument of its type in the visible part of the spectrum. The instrument is capable of absolute radiometric measurements in all of its 32 bands. ASAS can be easily mounted in small aircraft as well as high altitude craft such as the U-2, taking into account also the possibility of a use in the Space Shuttle. The instrument consists of three separate subsystems. Attention is given to the optics, the detector array, data storage, data retrieval, and system performance.
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  • 71
    Publication Date: 2011-08-19
    Description: The NASA Imaging Spectrometer program has the objective to develop the next generation of earth remote sensing systems. One part of the program is concerned with the production of advanced short-wavelength mercury cadmium telluride (HgCdTe) hybrid focal plane arrays (FPAs). These arrays are needed for several instruments, including the Shuttle Imaging Spectrometer (SIS), which requires a mosaic of six 64 x 64-element arrays with a cutoff wavelength of 2.5 microns. A device description is provided and the test results are considered. The Airborne Imaging Spectrometer (AIS) is discussed, taking into account an instrument description, focal plane requirements, and AIS results.
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  • 72
    Publication Date: 2011-08-19
    Description: The development and current status of InSb line arrays for astronomy are reviewed. Instrument concepts are currently being developed for an infrared instrument for NASA's Space Telescope which would use such detectors for both spectroscopy and imaging. Preliminary performance measurements are given for a simple pushbroom camera, using a 128-element line array, designed for operation on the 24-inch Cassegrain telescope at the JPL Table Mountain Observatory. The design and construction of the camera are described.
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  • 73
    Publication Date: 2011-08-19
    Description: Since the first introduction of charge-coupled devices (CCDs) in 1970, CCDs have been considered for applications related to memories, logic circuits, and the detection of visible radiation. It is pointed out, however, that the mass market orientation of CCD development has left largely untapped the enormous potential of these devices for advanced scientific instrumentation. The present paper has, therefore, the objective to introduce the CCD characteristics to the scientific community, taking into account prospects for further improvement. Attention is given to evaluation criteria, a summary of current CCDs, CCD performance characteristics, absolute calibration tools, quantum efficiency, aspects of charge collection, charge transfer efficiency, read noise, and predictions regarding the characteristics of the next generation of silicon scientific CCD imagers.
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  • 74
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    Publication Date: 2011-08-19
    Description: Small, compact, and rugged IF spectrometers are needed in high resolution heterodyne receivers designed for a new generation of space-borne telescopes planned for the next decade. Acousto-optic Spectrometers (AOS) promise to provide the necessary bandwidth and resolution in a package which is compact, power efficient, and ruggedized for space applications. Sensitivity, linearity, and stability are the primary goals of an astronomical receiver and these features must be demonstrated in order for an AOS to be accepted in place of more conventional RF or digital technology.
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  • 75
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    In:  Other Sources
    Publication Date: 2011-08-18
    Description: An analytical method for determining the absorbed energy calibration of an IR bolometer from purely electrical measurements is presented. The technique is targeted at detectors with purely electrical nonlinearities. It is shown that the responsivity can be derived from the I-V plot if the limiting high-frequency impedance is measured. The electrical nonlinearity is then the difference between the impedance and the dc resistance. The model is used for designing a circuit for measuring the relative impedance parameters. The results are applicable to studies of IR sources and the detection of energy pulses with bolometers.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 3181-318
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  • 76
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    Publication Date: 2011-08-18
    Description: In this paper the viability of the solar disk sextant concept is evaluated, the optimum parameters required to carry out solar variability studies, which are the mission objectives, are derived. The experimental environment is first discussed, followed by the application of the finite Fourier transform definition (FFTD) to the detector array data. The requirements on the optical system are studied next. A computer program was carried out simulating solar edge data and FFTD. From this study, it is concluded that the required accuracy of measurement may be reached using currently available detector array technology, a focal ratio of the optical system in excess of 90, and an entrance aperture of 22 cm. The guidance error must be small enough to require no more than a correction rate of 0.1 arcsec/sec. All these conditions are well within current technology.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1226-122
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  • 77
    Publication Date: 2011-08-18
    Description: Previously cited in issue 05, p. 643, Accession no. A83-16688
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: AIAA Journal (ISSN 0001-1452); 22; 504-511
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  • 78
    Publication Date: 2011-08-18
    Description: Extensive calculations and simulations have shown that the instrumental background in a coaxial germanium photon detector flown at balloon altitudes or in space, can be substantially reduced by segmenting the outer contact. The contact is divided into horizontal strips around the side of the detector, giving it many characteristics similar to that of a stack of planar detectors. By choosing different segment coincidence requirements in different energy ranges, one can obtain a factor of approx. 2 increase in sensitivity to spectral lines between 40 keV and 1 MeV, compared with an unsegmented detector. The reverse electrode configuration (using n-type germanium), with the p contact outside, is preferred for this application due to its thin dead layer and resistance to radiation damage in space. A small two segment n type detector is being developed to serve as a prototype for larger multisegment devices. Results of this development effort and of detector tests are presented. Previously announced in STAR as N84-13039
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-31; 307-311
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  • 79
    Publication Date: 2011-08-18
    Description: A low-cost digital system based on an 8-bit Apple II microcomputer has been designed to provide on-line control, data acquisition, and evaluation of sound absorption measurements in gases. The measurements are conducted in a resonant tube, in which an acoustical standing wave is excited, the excitation removed, and the sound absorption evaluated from the free decay envelope. The free decay is initiated from the computer keyboard after the standing wave is established, and the microphone response signal is the source of the analog signal for the A/D converter. The acquisition software is written in ASSEMBLY language and the evaluation software in BASIC. This paper describes the acoustical measurement, hardware, software, and system performance and presents measurements of sound absorption in air as an example.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 55; 116-118
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  • 80
    Publication Date: 2011-08-18
    Description: A high-temperature Hall-effect apparatus is described which allows measurements up to temperatures greater than 1200 K using the van der Pauw method. The apparatus was designed for measurements on refractory materials having high charge carrier concentrations and generally low mobilities. Pressure contacts are applied to the samples. Consequently, special contacting methods, peculiar to a specific sample material, are not required. The apparatus has been semiautomated to facilitate measurements. Results are presented on n- and p-type silicon.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 55; 110-113
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  • 81
    Publication Date: 2011-08-19
    Description: CRUX is the first engineering flight experiment designed to test for the incidence of upsets in microcircuits by energetic particles. Harris HM 6504 4K x 1 static CMOS RAM's were used as the test device types in a 1.3 megabit memory which flew on two Shuttle flights. Ground (cyclotron) test information led to a prediction of about one error every 1000 days. No errors were experienced in 10 days of flight. While data were not in conflict with the error prediction and do support it, quantitative validation of the modeling for upsets is not statistically possible. Follow-on hardware (CRUX III) incorporates five different state-of-the-art microcircuits, and is scheduled for flight in October 1984.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-31; 1178-118
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  • 82
    Publication Date: 2011-08-19
    Description: A technique has been developed for fabricating electromagnetic induction coils in a reproducible manner. The process utilizes a split mandrel that can be disassembled to remove the mandrel from the coil. The technique has increased coil production rates by a factor of 8 over the freehand winding method. The success rate for producing a functional levitation coil has been increased from 50 percent to 95 percent. The levitation coil designed during this work has successfully levitated and melted a variety of alloys including Cu, Ag, Ag-Ni, Cu-Fe, Fe-C, and Nb-Ge. W was also levitated but not melted at temperatures as high as 2700 C. The highest sample melt temperature achieved was 2400 C for the Nb-Ge samples.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Review of Scientific Instruments (ISSN 0034-6748); 55; 1859-186
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  • 83
    Publication Date: 2011-08-19
    Description: Attention is given to 1.2 years of data from two Michelson-Gale long fluid tiltmeters, one long center pressure tiltmeter, and a shallow borehole tiltmeter, which have been in operation at Pinon Flat Observatory in Southern California. The most stable tilt record shows a secular rate of 0.28 microrad/a, which may be real. Comparisons undertaken among instruments have identified more and less successful measurement techniques. It is concluded that even the best existing sensors must be improved in order to measure continuous tectonic motions.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Geophysical Research Letters (ISSN 0094-8276); 11; 963-966
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  • 84
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: A disk-crack monitor is described that is suitable for use on the ground or in flight. The system consists of an engine-mounted eddy current sensor, a series capacitance in each leg of the sensor circuit, and a capacitance-conductance bridge followed by an oscilloscope capable of advanced signal processing. It was applied to the detection of service-induced cracks in the first-stage turbine wheel of a helicopter engine. A 3.5 mm long radial fatigue crack plus smaller cracks, all located in the blade root region of the wheel, were detected during engine test stand operation at ground idle speed and temperature. The calculation of the value of series capacitance is also presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Materials Evaluation (ISSN 0025-5327); 42; 1374-137
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  • 85
    Publication Date: 2011-08-19
    Description: A calibration procedure for diffraction-based particle-sizing instruments using multielement detectors is briefly reviewed. The effects of multiple scattering due to dense sprays on the calibration of these instruments are then examined over a range of sprays with Sauter mean diameters from 20 to 55 microns. An empirical scheme to correct for changes in calibration due to dense sprays or other scattering media is presented.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Optical Engineering (ISSN 0091-3286); 23; 626-630
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  • 86
    Publication Date: 2011-08-18
    Description: An attempt is made to develop a better mathematical description of optical scattering phenomena, in order to construct an optical scattering apparatus for reliable and routine measurements of roughness parameters without resorting to comparator standards. After a brief outline of optical scattering theory, a description is presented of an experimental instrument for measuring surface roughness which incorporates optical scattering principles. The instrument has a He-Ne laser which illuminates the test surface at a variable angle of incidence. Scattered light distribution is detected by an array of 87 fiber-optic sensors positioned in a rotating semicircular yoke. The output from the detector is digitized and analyzed in a laboratory computer. For a comparison with experimental data, theoretical distributions are calculated by substituting the roughness profiles into the operand of and integral equation for electromagnetic scattering developed by Beckmann and Spizzichino (1963). A schematic diagram of the instrument is provided and the general implications of the experimental results are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Journal of Research; 89; 3-16
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  • 87
    Publication Date: 2011-08-18
    Description: A study of a low-rate monochrome video compression system is presentd in this paper. This system is a conditional-replenishment coder that uses two-dimensional Walsh-transform coding within each video frame. The conditional-replenishment algorithm works by transmitting only the portions of an image that are changing in time. This system is augmented with a motn-prediction algorithm that measures spatial dispalcement parameters from frame to frame, and codes the data using these parameters. A comparison is made between the conditional-replenishment system with, and without, the motion-predictinalgorthm. Subsampling in time is ued to maintain the data rate rate at a fixed value. Average bit rates of 1 bit/picture element (pel) to 1/16 bit/pel are considered. The resultant performance of the compression simulations is presented in terms of the average frame rates produced.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: IEEE Transactions on Electromagnetic Compatibility (ISSN 0018-9375); EMC-26; 134-142
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  • 88
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    In:  Other Sources
    Publication Date: 2011-08-18
    Description: In this modification of the schlieren apparatus the knife-edge is replaced by a radial-rainbow filter with a transparent center and opaque surround. Consequently, refractive-index inhomogeneities in the test section appear varicolored, whereas uniformities appear white. The rainbow schlieren is simple, is easy to use, and accentuates detail regarding inhomogeneities more than the ordinary schlieren. The rainbow schlieren permits quantitative evaluation of certain refractive-index distributions, including turbulence, by simple calculations from observations of hue rather than irradiance.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 2449-246
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  • 89
    Publication Date: 2011-08-18
    Description: The linearity of an intensified silicon photodiode array multichannel detector is studied with coherent anti-Stokes Raman and other similar signals. Studies with diffuse and focused (spherically and cylindrically) signals resolved apparent saturation problems which limit the dynamic range of the detector. In addition, it has been shown that there is no short-range wavelength (473-532-nm) dependence on this saturation. Theoretical explanations for these phenomena are also included.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 2369-237
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  • 90
    Publication Date: 2011-08-18
    Description: The results of two computer simulations demonstrate the feasibility of using the nonoverlapping redundant array (NORA) to form three-dimensional images of objects with X-rays. Pinholes admit the X-rays to nonoverlapping points on a detector. The object is reconstructed in the analog mode by optical correlation and in the digital mode by tomographic computations. Trials were run with a stick-figure pyramid and extended objects with out-of-focus backgrounds. Substitution of spherical optical lenses for the pinholes increased the light transmission sufficiently that objects could be easily viewed in a dark room. Out-of-focus aberrations in tomographic reconstruction could be eliminated using Chang's (1976) algorithm.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 2239-224
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  • 91
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    Publication Date: 2011-08-18
    Description: The dual-beam diode laser spectrometer described by Jennings (1980) is adapted to use a 50-cm confocal etalon for frequency calibration. The collimated radiation from the laser is split at a wedged ZnSe window, and the reference beam is then focused at the midpoint of the etalon length. After the etalon, the reference beam is recollimated and continues its regular path to the monochromator and detectors. An aperture is placed before the etalon in order to limit the entrance beam diameter to approximately 5 mm. Both ends of the etalon are furnished with two-axis adjustments. Initial alignment is achieved using an He-Ne laser, and final optimization involves adjustment of the cavity length as well as the etalon pitch and yaw. The 50-cm confocal etalon produces fringes separated by 150 MHz (0.005/cm). With the aid of a CO2 laser, it is found to have fringe widths (FWHM) of 2 MHz. The confocal etalon makes it possible to improve the accuracy of relative frequency measurements in diode laser spectra and to check the spectral purity and stability of the laser during the recording of spectra.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1299-130
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  • 92
    Publication Date: 2011-08-18
    Description: In this paper the performance of a plausible configuration for the solar disk sextant, an instrument to be used to monitor the solar diameter, is evaluated. Overall system requirements are evaluated, and tolerable uncertainties are obtained. It is concluded that by using a beam splitting wedge, a folded optics design can be used to measure the solar diameter to an accuracy of 10 to the -6th, despite the greater aberrations present in such optical systems.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 1230-123
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  • 93
    Publication Date: 2011-08-18
    Description: A new type of bolometer detector for the millimeter and submillimeter spectral range is described. The bolometer is constructed of silicon using integrated circuit fabrication techniques. Ion implantation is used to give controlled resistance vs temperature properties as well as extremely low 1/f noise contacts. The devices have been tested between 4.2 and 0.3 K. The best electrical NEP measured is 4 x 10 to the -16th W/Hz to the 1/2 at 0.35 K between 1- and 10-Hz modulation frequency. This device had a detecting area of 0.25 sq cm and a time constant of 20 msec at a bath temperature of 0.35 K.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 910-914
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  • 94
    Publication Date: 2011-08-18
    Description: IR gas correlation spectroscopy is a sensitive technique for the measurement of small Doppler shifts in spectra. This technique also exhibits several important advantages over alternative methods in the remote sensing of stratospheric and mesospheric winds from spacecraft. Attention is presently given to laboratory tests demonstrating gas correlation spectroscopy's quantitative measurement of small Doppler shifts in spectra, whose close agreement with theoretical predictions suggests that measurements of the change in the radiant flux through a gas correlation spectrometer can be used to measure the relative velocity between gas and instrument for a moving parcel of gas.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 527
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  • 95
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    Publication Date: 2011-08-18
    Description: Aging tests for several batches of Kodak type 101 emulsion show that storage conditions significantly influence how well the film will maintain its sensitometric properties, with sensitivity and density increasing to a maximum during this period. Any further aging may result in higher fog levels and sensitivity loss. It is noted that storage in an environment free of photographically active compounds allows film property optimization, and that film batches with different sensitivities age differently. Emulsions with maximum 1700-A sensitivity are 2.5 times faster than those at the low end of the sensitivity scale. These sensitive emulsions exhibit significantly accelerated changes in aging properties. Their use in space applications requires careful consideration of time and temperature profiles, encouraging the use of less sensitive emulsions when the controllability of these factors is limited.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 589-596
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  • 96
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    Publication Date: 2011-08-18
    Description: A novel method is presented for the investigation of Fabry-Perot etalon defects, incorporating the effects of microsurface imperfection, bowing, and departure from parallelism, as well as the effect of finite aperture on the etalon, into the perturbation function. The tolerance imperfections of reflective layers can be incorporated into the transfer coefficients of a noncorrugated thin-film system, and any defect can be investigated either separately or in combination with others through the use of the appropriate analytical or numerical simulation of the corrugated function. In the context of numerical computation, the present method permits the simulation and evaluation of different specific situations. The expressions derived for the transfer coefficients of a corrugated, equidistant thin film system may be applicable to other branches of applied optics.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 621-627
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  • 97
    Publication Date: 2011-08-18
    Description: Theoretical expressions for Johnson noise and thermal noise in bolometers are considered, and optimization with respect to thermal conductivity and bias power is performed. Numerical approximations are given for the ultimate NEP of bolometers as a function of material parameters and compared with photon noise including photon correlations. A resonating capacitor is shown to improve the coupling to an amplifier, so that the amplifier need not limit performance even for very low temperature bolometers.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Applied Optics (ISSN 0003-6935); 23; 584-588
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  • 98
    Publication Date: 2016-06-07
    Description: Development of electrical resistance strain gages for static strain measurements of nickel or cobalt superalloy parts inside a gas turbine engine on a test stand was inititated. Measurements of this type are of great importance because without reliable knowledge of the stresses and strains which exist in specific components, it will be difficult to fully appreciate where improvements in design and materials can be implemented. The first part of this effort consists of a strain gage alloy development program which will be followed by an investigation of complete strain gage systems. Efforts to date are summarized.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Lewis Research Center Turbine Engine Hot Section Technology, 1984; 6 p
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  • 99
    Publication Date: 2016-06-07
    Description: Candidate concepts capable of generating dynamic temperatures were identified and analyzed for use in verifying experimentally the frequency response of the dynamic gas temperature measurement system. A rotating wheel concept and one other concept will be selected for this purpose. Modifications to the data reduction code algorithms developed were identified and evaluated to reduce substantially the data reduction execution time. These modifications will be incorporated in a new data reduction program to be written in FORTRAN IV.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA. Lewis Research Center Turbine Engine Hot Section Technology, 1984; 10 p
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  • 100
    Publication Date: 2016-06-07
    Description: There is a continuing interest and need for resistance strain gages capable of making static strain measurements on components located in the hot section of gas turbine engines. A paper by Tsen-tai Wu describes the development and evaluation of high temperature gauges fabricated from specially developed Fe-Cr-Al-V-Ti-Y alloy wire. Several of these gages and a quantity of P12-2 ceramic adhesive were purchased for evaluation. Nine members of the aircraft turbine engine community were invited to participate in an evaluation of these gages. Each participant was sent one strain gage, a small amount of ceramic adhesive, instructions for mounting the gage on a test beam, and a set of suggestions for the experiment. Data on gage factor variation with temperature, apparent strain, and drift are discussed.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: Turbine Engine Hot Section Technology, 1984; 8 p
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