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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 271 records · Page 15
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NASA NTRS1979

Charge injection device as a candidate sensor for stellar tracking

Charge transfer devices (CTDs) are superior to the image dissector as stellar tracking sensors, considering their low voltage requirements, insensitivity to magnetic fields, good linearity, and low weight and power. An analysis of one type of CTD, called the charge injection device (CID), revealed an X-Y addressing capability which provides exceptional flexibility in array readout and results in enhanced S/N capability, a surface channel device which produces a larger dynamic range of operation, and exceptional and unique tolerance to optical overloads. A 128 row by 128 column CID array processed on silicon was evaluated in a cooled breadboard camera, and measured results indicate projected performance parameters of a large area CID array as follows: 20 micron square sensing site, noise not greater than 25 carriers per pixel, quantum yield of approximately 40% from 0.4 to 1.0 micron, and cooling requirements on the order of 0 degrees C.

Jones, C. S., Jr.↗
NASA NTRS1999

TurboBrayton Cryocooler: A Flight Worthy and Promising Future

A new development in cryocooler technology, a reverse TurboBrayton cycle cryocooler, developed by Creare, Inc. of Hanover, NH, has now been flight tested. This cooler provides high reliability and long life. With no linear moving components common in current flight cryocoolers, the TurboBrayton cooler requires no active control systems to provide a vibration-free signature. The cooler provides first stage cooling for advanced cryogenic systems and serves as a direct replacement for stored cryogen systems with a longer lifetime. Following a successful flight on STS-95, a TurboBrayton cryocooler will be flown on Hubble Space Telescope (HST) in 2000 to provide renewed refrigeration capability for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). The TurboBrayton cycle cooler is a promising technology already being considered for additional flight programs such as Next Generation Space Telescope (NGST) and Constellation X. These future missions require an advanced generation of the cooler that is currently under development to provide cooling at 10K and less. This paper presents an overview of the current generation cooler with recent flight test results and details the current plans and development progress on the next generation TurboBrayton technology for future missions.

Gibbon, Judith A.↗
DOE OSTI2021

Implosion dynamics of triple-nozzle gas-puff z pinches on COBRA

Experiments on the 1-MA, 220-ns COBRA generator at Cornell University were conducted to provide detailed measurements of structured cylindrical gas-puff z pinches. In the experiments, a 7 cm diameter triple-nozzle gas valve assembly with concentric outer and inner annular nozzles and a central gas jet initialize the z-pinch load with various working gases, radial density profiles, and externally applied axial magnetic fields. Planar laser-induced fluorescence provides a measure of the initial neutral gas density of the load, while three-frame laser shearing interferometry and multi-frame extreme ultraviolet (XUV) cameras reveal the formation and propagation of a magneto-Rayleigh–Taylor (MRT) unstable shock layer. Implosion trajectories are compared to simple, experimentally informed models and found to be in good agreement. Differences in the structure of the accelerating plasma sheath and evolution of the MRT instability are observed for different gas species and axial magnetic field strengths, correlating with differences in pinch uniformity and x-ray emission. Here, the average instability growth is compared to linear MRT theory predictions using the instantaneous acceleration of the best-fit implosion models and characteristic instability wavelength, with the effective Atwood number and seed perturbation size as fit parameters. For high density argon center jets, ionization prior to the arrival of the imploding plasma sheath suggests a heating mechanism consistent with photoionization by XUV self-emission.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

TomocuPy – efficient GPU-based tomographic reconstruction with asynchronous data processing

Fast 3D data analysis and steering of a tomographic experiment by changing environmental conditions or acquisition parameters require fast, close to real-time, 3D reconstruction of large data volumes. Here a performance-optimized TomocuPy package is presented as a GPU alternative to the commonly used central processing unit (CPU) based TomoPy package for tomographic reconstruction. TomocuPy utilizes modern hardware capabilities to organize a 3D asynchronous reconstruction involving parallel read/write operations with storage drives, CPU–GPU data transfers, and GPU computations. In the asynchronous reconstruction, all the operations are timely overlapped to almost fully hide all data management time. Since most cameras work with less than 16-bit digital output, the memory usage and processing speed are furthermore optimized by using 16-bit floating-point arithmetic. As a result, 3D reconstruction with TomocuPy became 20–30 times faster than its multi-threaded CPU equivalent. Full reconstruction (including read/write operations and methods initialization) of a 2048 3 tomographic volume takes less than 7 s on a single Nvidia Tesla A100 and PCIe 4.0 NVMe SSD, and scales almost linearly increasing the data size. To simplify operation at synchrotron beamlines, TomocuPy provides an easy-to-use command-line interface. Efficacy of the package was demonstrated during a tomographic experiment on gas-hydrate formation in porous samples, where a steering option was implemented as a lens-changing mechanism for zooming to regions of interest.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1975

Initial results from the S-056 X-ray telescope on Skylab

The S-056 instrument on Skylab-ATM consists of a glancing incidence X-ray telescope with a camera, five X-ray filters, and two small proportional counters to monitor X-rays from the whole sun in the wavelength range from 2 to 18 A. The telescope reflectivity and filter transmissions limit the photographs to the wavelength ranges from 6 to 18 A and from 27 to 37 A. Hence, the instrument is most useful for the study of active regions and solar activity. Active regions usually have bright cores which often appear as linear features straddling the magnetic field neutral line. A large loop appearing on the west limb in connection with prominence activity on Aug. 13, 1973, was analyzed using proportional counter data and photographs. Crude spectral analysis indicates the loop temperature reached 6 million K and the density was enhanced to a few times that obtained from quiet coronal models. Over a hundred solar flares were photographed during the three Skylab missions. Illustrative examples are discussed for solar flares and other transient coronal phenomena.

Mckenzie, D. L.↗
NASA NTRS1985

The Nagoya cosmic-ray muon spectrometer 3, part 4: Track reconstruction method

One of the greatest problems in measuring particle trajectories with an optical or visual detector system, is the reconstruction of trajectories in real space from their recorded images. In the Nagoya cosmic-ray muon spectrometer, muon tracks are detected by wide gap spark chambers and their images are recorded on the photographic film through an optical system of 10 mirrors and two cameras. For the spatial reconstruction, 42 parameters of the optical system should be known to determine the configuration of this system. It is almost impossible to measure this many parameters directly with usual techniques. In order to solve this problem, the inverse transformation method was applied. In this method, all the optical parameters are determined from the locations of fiducial marks in real space and the locations of their images on the photographic film by the non-linear least square fitting.

Shibata, S.↗
NASA NTRS2019

Principal Component Analysis of Up-The-Ramp Sampled Infrared Array Data

We describe the results of principal component analysis (PCA) of up-the-ramp sampled infrared (IR) array data from the Hubble Space Telescope wide field camera 3 (WFC3 IR), James Webb Space Telescope NIRSpec, and prototype Wide Field Infrared Survey Telescope’s wide field instrument detectors. These systems use, respectively, Teledyne H1R, H2RG, and H4RG-10 near-IR detector arrays with a variety of IR array controllers. The PCA shows that the Legendre polynomials approximate the principal components of these systems (i.e., they roughly diagonalize the covariance matrix). In contrast to the monomial basis that is widely used for polynomial fitting and linearization today, the Legendre polynomials are an orthonormal basis. They provide a quantifiable, compact, and (nearly) linearly uncorrelated representation of the information content of the data. By fitting a few Legendre polynomials, nearly all of the meaningful information in representative WFC3 astronomical datacubes can be condensed from 15 up-the-ramp samples down to 6 compressible Legendre coefficients per pixel. The higher order coefficients contain time domain information that is lost when one projects up-the-ramp sampled datacubes onto two-dimensional images by fitting a straight line, even if the data are linearized before fitting the line. Going forward, we believe that this time domain information is potentially important for disentangling the various nonlinearities that can affect IR array observations, i.e., inherent pixel nonlinearity, persistence, burn in, brighter-fatter effect, (potentially) nonlinear interpixel capacitance, and perhaps others.

Rauscher, Bernard J.↗
NASA NTRS2001

Simulation of MEMS for the Next Generation Space Telescope

The NASA Goddard Space Flight Center (GSFC) is developing optical micro-electromechanical system (MEMS) components for potential application in Next Generation Space Telescope (NGST) science instruments. In this work, we present an overview of the electro-mechanical simulation of three MEMS components for NGST, which include a reflective micro-mirror array and transmissive microshutter array for aperture control for a near infrared (NIR) multi-object spectrometer and a large aperture MEMS Fabry-Perot tunable filter for a NIR wide field camera. In all cases the device must operate at cryogenic temperatures with low power consumption and low, complementary metal oxide semiconductor (CMOS) compatible, voltages. The goal of our simulation efforts is to adequately predict both the performance and the reliability of the devices during ground handling, launch, and operation to prevent failures late in the development process and during flight. This goal requires detailed modeling and validation of complex electro-thermal-mechanical interactions and very large non-linear deformations, often involving surface contact. Various parameters such as spatial dimensions and device response are often difficult to measure reliably at these small scales. In addition, these devices are fabricated from a wide variety of materials including surface micro-machined aluminum, reactive ion etched (RIE) silicon nitride, and deep reactive ion etched (DRIE) bulk single crystal silicon. The above broad set of conditions combine to be a formidable challenge for space flight qualification analysis. These simulations represent NASA/GSFC's first attempts at implementing a comprehensive strategy to address complex MEMS structures.

Mott, Brent↗
NASA NTRS2004

Measurements of Infrared and Acoustic Source Distributions in Jet Plumes

The aim of this investigation was to use the linear phased array (LPA) microphones and infrared (IR) imaging to study the effects of advanced nozzle-mixing techniques on jet noise reduction. Several full-scale engine nozzles were tested at varying power cycles with the linear phased array setup parallel to the jet axis. The array consisted of 16 sparsely distributed microphones. The phased array microphone measurements were taken at a distance of 51.0 ft (15.5 m) from the jet axis, and the results were used to obtain relative overall sound pressure levels from one nozzle design to the other. The IR imaging system was used to acquire real-time dynamic thermal patterns of the exhaust jet from the nozzles tested. The IR camera measured the IR radiation from the nozzle exit to a distance of six fan diameters (X/D(sub FAN) = 6), along the jet plume axis. The images confirmed the expected jet plume mixing intensity, and the phased array results showed the differences in sound pressure level with respect to nozzle configurations. The results show the effects of changes in configurations to the exit nozzles on both the flows mixing patterns and radiant energy dissipation patterns. By comparing the results from these two measurements, a relationship between noise reduction and core/bypass flow mixing is demonstrated.

Agboola, Femi A.↗
NASA NTRS2004

Arrays of Bolometers for Far-infrared and Submillimeter Astronomy

We describe 12 x 32 arrays of semiconducting cryogenic bolometers designed for use in far-infrared and submillimeter cameras. These 12 x 32 arrays are constructed from 1 x 32 monolithic pop-up detectors developed at NASA Goddard Space Flight Center. The pop-up technology allows the construction of large arrays with high filling factors that provide efficient use of space in the focal planes of far-infrared and submillimeter astronomical instruments. This directly leads to a significant decrease in observing time. The prototype array is currently operating in SHARC II, a facility instrument in use at the Caltech Submillimeter Observatory (CSO). The elements of this array employ a bismuth absorber coating and quarter wave backshort to optimize the bolometer absorption for a passband centered at 350 microns. However, this resonant structure also provides good bolometer performance at 450 and 850 microns, the two additional SHARC II passbands. A second array is to be installed in the High-resolution Airborne Widebandwidth Camera (HAWC), a far-infrared imaging camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). This array is currently in the final stage of construction, and its completion is expected in early 2004. HAWC is scheduled for commissioning in 2005. The HAWC array employs titanium-gold absorbers and is optimized for uniform absorption from 40 to 300 microns to accommodate all four of its far-infrared passbands. We describe the details of the array construction including the mechanical design and electrical characterization of the constituent linear arrays, comparing the SHARC II and HAWC cases. We also summarize the overall characteristics of the final two-dimensional arrays. Finally, we show examples of array performance in the form of images obtained with SHARC II.

Chuss, D. T.↗
NASA NTRS1990

Deep narrow band imagery of the diffuse ISM in M33

Very deep narrow band images were obtained for several fields in the local group spiral galaxy M33 using a wide field reimaging Charge Coupled Device (CCD) camera on the 1.5 m telescope at Palomar Observatory. The reimaging system uses a 306 mm collimator and a 58 mm camera lens to put a 16 minute by 16 minute field onto a Texas Instruments 800 x 800 pixel CCD at a resolution of 1.2 arcseconds pixel (-1). The overall system is f/1.65. Images were obtained in the light of H alpha (S II) lambda lambda 6717, 6731, (O III) lambda 5007, and line-free continuum bands 100A wide, centered at 6450A and 5100A. Assuming a distance of 600 kpc to M33 (Humphreys 1980, Ap. J., 241, 587), this corresponds to a linear scale of 3.5 pc pixel (-1), and a field size of 2.8 kpc x 2.8 kpc. Researchers discuss the H alpha imagery of a field centered approx. equal to 8 minutes NE of the nucleus, including the supergiant HII region complex NGC 604. Two 2000 second H alpha images and two 300 second red continuum images were obtained of two slightly offset fields. The fields were offset to allow for discrimination between real emission and possible artifacts in the images. All images were resampled to align them with one of the H alpha frames. The continuum images were normalized to the line images using the results of aperture photometry on a grid of stars in the field, then the rescaled continuum data were directly subtracted from the line data.

Hester, J. Jeff↗
NASA NTRS2002

Hubble Space Telescope Pointing Performance Due to Micro-Dynamic Disturbances from the NICMOS Cryogenic Cooler

The Vibration Admittance Test (VET) was performed to measure the emitted disturbances of the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Cryogenic Cooler (NCC) in preparation for NCC installation onboard the Hubble Space Telescope (HST) during Servicing Mission 3B (SM3B). Details of the VET ground-test are described, including facility characteristics, sensor complement and configuration, NCC suspension, and background noise measurements. Kinematic equations used to compute NCC mass center displacements and accelerations from raw measurements are presented, and dynamic equations of motion for the NCC VET system are developed and verified using modal test data. A MIMO linear frequency-domain analysis method is used to compute NCC-induced loads and HST boresight jitter from VET measurements. These results are verified by a nonlinear time-domain analysis approach using a high-fidelity structural dynamics and pointing control simulation for HST. NCC emitted acceleration levels not exceeding 35 micro-g rms were measured in the VET and analysis methods herein predict 3.1 milli-areseconds rms jitter for HST on-orbit. Because the NCC is predicted to become the predominant disturbance source for HST, VET results indicate that HST will continue to meet the 7 milli-arcsecond pointing stability mission requirement in the post-SM3B era.

Clapp, Brian R.↗
NASA NTRS2010

Multiple Velocity Profile Measurements in Hypersonic Flows Using Sequentially-Imaged Fluorescence Tagging

Nitric-oxide planar laser-induced fluorescence (NO PLIF) was used to perform velocity measurements in hypersonic flows by generating multiple tagged lines which fluoresce as they convect downstream. For each laser pulse, a single interline, progressive scan intensified CCD (charge-coupled device) camera was used to obtain two sequential images of the NO molecules that had been tagged by the laser. The CCD configuration allowed for sub-microsecond acquisition of both images, resulting in sub-microsecond temporal resolution as well as sub-mm spatial resolution (0.5-mm horizontal, 0.7-mm vertical). Determination of axial velocity was made by application of a cross-correlation analysis of the horizontal shift of individual tagged lines. A numerical study of measured velocity error due to a uniform and linearly-varying collisional rate distribution was performed. Quantification of systematic errors, the contribution of gating/exposure duration errors, and the influence of collision rate on temporal uncertainty were made. Quantification of the spatial uncertainty depended upon the signal-to-noise ratio of the acquired profiles. This velocity measurement technique has been demonstrated for two hypersonic flow experiments: (1) a reaction control system (RCS) jet on an Orion Crew Exploration Vehicle (CEV) wind tunnel model and (2) a 10-degree half-angle wedge containing a 2-mm tall, 4-mm wide cylindrical boundary layer trip. The experiments were performed at the NASA Langley Research Center's 31-Inch Mach 10 Air Tunnel.

Bathel, Brett F.↗
NASA NTRS2018

Rayleigh Scattering Density Measurements from Ultrafast Lasers in High-Pressure, Cryogenic Wind Tunnels

The Rayleigh scattering signal from femtosecond laser pulses is examined for its utility at making instantaneous density measurements in the NASA Langley 0.3-m Transonic Cryogenic Tunnel. An electron-multiplying CCD camera is used to visualize Rayleigh scattering signal taken concurrently with velocity measurements utilizing the femtosecond laser tagging velocimetry technique (FLEET). The results indicate a strong potential for making instantaneous measurements. Viable single-shot images are obtained over the full operational envelope of the facility, and shot-to-shot variations are found to be on average 6 percent (at 95 percent confidence level) and tend to decrease as the facility density is increased. The Rayleigh scattering signals observed before the optical focus exhibit a characteristically linear dependence on the mass-density of the gas, while signals after the focus exhibit a nonlinear (sublinear) density dependence, indicative of stronger absorption at higher densities. The measured Rayleigh scattering signals compare favorably to theoretical assessments made at the tunnel operating conditions.

Burns, Ross A.↗
DOE OSTI2021

Measurement of Deformation Heterogeneity During Shale Swelling Using Digital Image Correlation

Abstract Rock-fluid interactions in shale formations are one of the main sources of wellbore instability issues and inadequate stimulation performance. For better planning of fracturing operations and optimizing production from these reservoirs, it is important to understand the mechanisms behind these interactions. These issues are especially prevalent in clay-rich shales, such as Tuscaloosa Marine Shale, which is the subject of this study. Conventional techniques to quantify these shale-fluid interactions comprise of measuring swelling in powdered rock grains or measurement of deformation in the whole pieces of the core using a linear variable differential transformer and strain gages. However, the contribution from individual laminae to overall deformation cannot be evaluated using these methods. In this study, we developed an experimental setup to evaluate the spatial deformation in shale during interaction with water using digital image correlation (DIC). Deformation of two shale samples, with 34 wt% to 51 wt% clay content, was studied. White paint was used to generate a random speckle pattern on the specimen and then immersed in deionized water. The deformation process was captured using a digital camera and images were analyzed using DIC to quantify the deformation. The implementation of the DIC technique enables the visualization and quantification of spatial deformation in the specimen during interacting with water. The results show the localization of large strains in select laminations. The results provide a better understanding of shale deformation when interacting with water in comparison to traditional measurements that can provide only an average strain value.

Energy & Fuels↗
NASA NTRS2000

Phase Shift Interferometer and Growth Set Up to Step Pattern Formation During Growth From Solutions. Influence of the Oscillatory solution Flow on Stability

We have assembled an experimental setup based on Michelson interferometry with the growing crystal surface as one of the reflective surfaces. The crystallization part of the device allows optical monitoring of a face of a crystal growing at temperature stable within 0.05 C in a flow of solution of controlled direction and speed. The reference arm of the interferometer contains a liquid crystal element that allows controlled shifts of the phase of the interferograms. We employ an image-processing algorithm, which combines five images with a pi/2 phase difference between each pair of images. The images are transferred to a computer by a camera capable of capturing 60 frames per second. The device allows data collection on surface morphology and kinetics during the face layers growth over a relatively large area (approximately 4 sq. mm) in situ and in real time during growth. The estimated depth resolution of the phase shifting interferometry is approximately 50 Angstroms. The data will be analyzed in order to reveal and monitor step bunching during the growth process. The crystal chosen as a model for study in this work is KH2PO4 (KDP). This optically non-linear material is widely used in frequency doubling applications. There have been a number of studies of the kinetics of KDP crystallization that can serve as a benchmark for our investigations. However, so far, systematic quantitative characteristics of step interaction and bunching are missing. We intend to present our first quantitative results on the onset, initial stages and development of instabilities in moving step trains on vicinal crystal surfaces at varying supersaturation, flow rate, and flow direction. Behavior of a vicinal face growing from solution flowing normal to the steps and periodically changing its direction in time was considered theoretically. It was found that this oscillating flow reduces both stabilization and destabilization effects resulted from the unidirectional solution flow directed up the step stream and down the step stream. This reduction of stabilization and destabilization comes from effective mixing which entangles the phase shifts between the spatially periodic interface perturbation and the concentration wave induced by this perturbation. Numerical results and simplified mixing criterion will be discussed.

Chernov, Alex A.↗
NASA NTRS2001

Demonstration of Imaging Fourier Transform Spectrometer (FTS) Performance for Planetary and Geostationary Earth Observing

The combination of massively parallel spatial sampling and accurate spectral radiometry offered by imaging FTS makes it extremely attractive for earth and planetary remote sensing. We constructed a breadboard instrument to help assess the potential for planetary applications of small imaging FTS instruments in the 1 - 5 micrometer range. The results also support definition of the NASA Geostationary Imaging FTS (GIFTS) instrument that will make key meteorological and climate observations from geostationary earth orbit. The Planetary Imaging FTS (PIFTS) breadboard is based on a custom miniaturized Bomen interferometer that uses corner cube reflectors, a wishbone pivoting voice-coil delay scan mechanism, and a laser diode metrology system. The interferometer optical output is measured by a commercial infrared camera procured from Santa Barbara Focalplane. It uses an InSb 128x128 detector array that covers the entire FOV of the instrument when coupled with a 25 mm focal length commercial camera lens. With appropriate lenses and cold filters the instrument can be used from the visible to 5 micrometers. The delay scan is continuous, but slow, covering the maximum range of +/- 0.4 cm in 37.56 sec at a rate of 500 image frames per second. Image exposures are timed to be centered around predicted zero crossings. The design allows for prediction algorithms that account for the most recent fringe rate so that timing jitter produced by scan speed variations can be minimized. Response to a fixed source is linear with exposure time nearly to the point of saturation. Linearity with respect to input variations was demonstrated to within 0.16% using a 3-point blackbody calibration. Imaging of external complex scenes was carried out at low and high spectral resolution. These require full complex calibration to remove background contributions that vary dramatically over the instrument FOV. Testing is continuing to demonstrate the precise radiometric accuracy and noise characteristics.

Revercomb, Henry E.↗
NASA NTRS2004

Numerical and Experimental Dynamic Characteristics of Thin-Film Membranes

Presented is a total-Lagrangian displacement-based non-linear finite-element model of thin-film membranes for static and dynamic large-displacement analyses. The membrane theory fully accounts for geometric non-linearities. Fully non-linear static analysis followed by linear modal analysis is performed for an inflated circular cylindrical Kapton membrane tube under different pressures, and for a rectangular membrane under different tension loads at four comers. Finite element results show that shell modes dominate the dynamics of the inflated tube when the inflation pressure is low, and that vibration modes localized along four edges dominate the dynamics of the rectangular membrane. Numerical dynamic characteristics of the two membrane structures were experimentally verified using a Polytec PI PSV-200 scanning laser vibrometer and an EAGLE-500 8-camera motion analysis system.

Young, Leyland G.↗