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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

US Navy superconductivity program

Both the new high temperature superconductors (HTS) and the low temperature superconductors (LTS) are important components of the Navy's total plan to integrate superconductivity into field operational systems. Fundamental research is an important component of the total Navy program and focuses on the HTS materials. Power applications (ship propulsion) use LTS materials while space applications (millimeter wave electronics) use HTS materials. The Space Experiment to be conducted at NRL will involve space flight testing of HTS devices built by industry and will demonstrate the ability to engineer and space qualify these devices for systems use. Another important component of the Navy's effort is the development of Superconducting Quantum Interference Device (SQUID) magnetometers. This program will use LTS materials initially, but plans to implement HTS materials as soon as possible. Hybrid HTS/LTS systems are probable in many applications. A review of the status of the Navy's HTS materials research is given as well as an update on the Navy's development efforts in superconductivity.

Gubser, Donald U.↗
NASA NTRS1993

Germanium Resistance Thermometer For Subkelvin Temperatures

Improved germanium resistance thermometer measures temperatures as small as 0.01 K accurately. Design provides large area for electrical connections (to reduce electrical gradients and increase sensitivity to changes in temperatures) and large heat sink (to minimize resistance heating). Gold pads on top and bottom of germanium crystal distribute electrical current and flow of heat nearly uniformly across crystal. Less expensive than magnetic thermometers or superconducting quantum interference devices (SQUID's) otherwise used.

Castles, Stephen H.↗
NASA NTRS1993

Sandwich-Geometry YBa(2)Cu(3)O(7-delta)/Au/Nb SNS Devices

Superconductor/normal-conductor/superconductor (SNS) devices in which electronically active layers consist of high-temperature superconductor YBa(2)Cu(3)O(7-delta), normal conductor Au, and conventional superconductor Nb, fabricated in sandwich geometry. Devices and processes by which fabricated are part of continuing effort to develop SNS microbridges for use in superconducting quantum interference devices (SQUIDS's) or as mixers or local oscillators operating at frequencies of hundreds of gigahertz. Results show promise for manufacture of practical devices.

Foote, Marc C.↗
NASA NTRS1993

Powering the superwind in NGC 253

NGC 253 is a prototypical moderate nuclear starburst galaxy. It is a barred SBc spiral galaxy at a distance of approximately 3 Mpc and can be studied on scales down to 15 pc in the optical and near IR. It is a bright IRAS source with a flux of 1000 Jy at 60 microns and a FIR luminosity of 3 x 10(exp 10) solar luminosity. It has a strong Br(gamma) emission line, a signature of ongoing massive star formation and deep CO absorption bands, which are indicative of the dominance of red supergiants in the near IR. It contains a population of compact radio sources, similar to those seen in M82. Optical spectra show that the nucleus is heavily reddened, with a Balmer decrement of approximately 30. NGC 253 possesses a 'superwind,' seen both in x-ray emission and in optical line emission. Nuclear ejection was first suggested to explain the kinematics of the nuclear region. We have obtained J, H, and K images of the entire galaxy at 1.3 arcsec/pixel (18 pc/pixel) using the superconducting quantum interference device (SQUID) on the KPNO 1.3 m. We have constructed a mosaic of 180 s exposures which traces the galaxy over much of its optical extent. The data were shifted, rotated, magnified, and calibrated following normal practice.

Watson, Alan↗
NASA NTRS1993

Concept for a high-resolution thermometer utilizing the temperature dependence of the magnetic penetration depth

A thermometer using the temperature dependence of the magnetic penetration depth in superconductors is described which has the potential for temperature resolution, when using a dc SQUID readout, on the order of 1 pK. One such device has been fabricated and characterized to demonstrate proof of concept. It consists of primary and secondary coils of NbTi wire wound on a copper toroidal core on which a thin layer of In (Tc = 3.4 K) has been deposited. The temperature dependence of the mutual inductance, M(T), or self-inductance, is used to detect changes in temperature. Measurements of M(T) have been made with an ac excitation of the primary for various frequencies and peak magnetic field strengths. Estimates of ultimate temperature resolution are given.

Shirron, P. J.↗
NASA NTRS1993

Comparative magnetic and thermoanalytical study of two enstatite chondrites: Adhi Kot and Atlanta

With allowance for the discussion of classification of enstatite chondrites and their relation to aubrites, the obtained magnetic and thermoanalytical data is submitted to be considered as additive arguments. Our study covered the Adhi Kot (EH4) and Atlanta (EL6). meteorites belonging to two distinct groups of enstatite chondrites. Applying AF demagnetization the intensity of natural remanent magnetization (NRM) was measured and the mean magnetic susceptibility of the samples was determined. The differential thermal (DTA) and thermogravimetric (TG) curves were obtained for meteorites under study. For measurements of the intensity of NRM, a superconducting cryomagnetometer SQUID (2 G Enterprise, USA), while magnetic susceptibility Kappabridge KLY-2 (Czechoslovakia) were used. The abbreviated magnetic data sheets are given. The values 786 x 10(exp -4)A/mkg and 196.1 x 10(exp -4)A/mkg were obtained as NRM intensities for Atlanta and Adhi Kot respectively, while 17.4 x 10(exp -6) SIu/kg and 43.4 x 10(exp -6) SIu/kg for their susceptibilities. Both meteorites proved to be strongly magnetized. The demagnetization down to 3.2 percent of NMR was received for Atlanta at AF field intensity of 250 Oe. For Adhi Kot at this level rested 13.2 percent of NRM intensity, this sample being demagnetized without change of direction till 750 Oe field. The demagnetization curves are similar to those obtained for Abee (EL4) chondrite by Sugiura and Strangway. Against Abee the Adhi Kot exhibited a little bit steeper downfall, and in both cases dominate one component of magnetization. The DTA and TG curves were obtained with Rigaku-Denki thermoanalytical instrument. The DTA curves exhibit striking similarity in their shape and relatively close temperature values for various features. The same is valid for TG curves. The higher values for TG for Adhi Kot express its higher content of oxydable (Fe, Ni) whose oxidation in air is reached at 1000-1200 C.

Krol, Elizabeth↗
NASA NTRS1993

Software quality: Process or people

This paper will present data related to software development processes and personnel involvement from the perspective of software quality assurance. We examine eight years of data collected from six projects. Data collected varied by project but usually included defect and fault density with limited use of code metrics, schedule adherence, and budget growth information. The data are a blend of AFSCP 800-14 and suggested productivity measures in Software Metrics: A Practioner's Guide to Improved Product Development. A software quality assurance database tool, SQUID, was used to store and tabulate the data.

Palmer, Regina↗
NASA NTRS1995

Progress of applied superconductivity research at Materials Research Laboratories, ITRI (Taiwan)

A status report based on the applied high temperature superconductivity (HTS) research at Materials Research Laboratories (MRL), Industrial Technology Research Institute (ITRI) is given. The aim is to develop fabrication technologies for the high-TC materials appropriate to the industrial application requirements. To date, the majorities of works have been undertaken in the areas of new materials, wires/tapes with long length, prototypes of magnets, large-area thin films, SQUID's and microwave applications.

Liu, R. S.↗
NASA NTRS1995

Superconductivity in Russia: Update and prospects

The research projects and new technological developments that have occured in Russia are highlighted in this document. Some of the research discussed includes: x-ray structure analysis of YBCO superconducting single crystals and accompanying phase transformations; the role of electron-electron interaction in High Temperature Superconductors (HTSC); the formation of Cooper pairs in crystals; the synthesis and research on a new family of superconductors based on complex copper and mercury oxides (HgBa2CuO4 + alpha and HgBa2CaCu2O6 + alpha); methods for the extraction of higher (up to C200) fullerenes and metalfullerenides has been developed; and process of production of Josephson junctions and development of SQUID's.

Ozhogin, V.↗
NASA NTRS1995

Processing and property evaluation of metal matrix superconducting materials

Metal - superconductor (YBCO) systems have been prepared and characterized by resistivity, ac susceptibility and dc SQUID magnetic moment measurements. The silver composites showed superconducting transition for all the composites processed and the superconducting transition temperature tends to depend upon the concentration of the silver in the composite. Aluminum composites showed an unusual resistivity results with two transitions around 90 K and 120 K. The superconducting property of silver composites can be explained qualitatively in terms of the proximity theory that has been suggested for the low temperature superconductors.

Rao, Appajosula S.↗
NASA NTRS1995

High-performance passive microwave survey on Josephson Junctions

The quasi-optical generations of images of objects with their internal structure in millimeter (MM) and submillimeter (SMM) bands is one of prime problems of modern radioelectronics. The main advantage of passive MM imaging systems in comparison with visible and infrared (IR) systems is small attenuation of signals in fog, cloud, smoke, dust and other obscurants. However, at a panoramic scanning of space the observation time lengthens and thereby the information processing rate becomes restricted so that single-channel system cannot image in real time. Therefore we must use many radiometers in parallel to reduce the observation time. Such system must contain receiving sensors as pixels in multibeam antenna. The use of Josephson Junctions (JJ) for this purpose together with the cryoelectronic devices like GaAs FET (field effect transistors) or SQUIDS for signal amplifications after JJ is of particular interest in this case.

Denisov, A. G.↗
NASA NTRS1996

Design of a Superconducting Magnetic Suspension System for a Liquid Helium Flow Experiment

We discuss a preliminary design for a superconducting magnetic suspension system for measurement of drag on rotationally symmetric bodies in liquid helium. Superconducting materials are a natural choice for liquid helium studies, since temperatures are well below most critical temperatures, so that the resulting heat load is negligible. Also, due to its diamagnetic properties, a superconducting model (for example made or coated with Nb) is inherently stable against disturbances. Issues which we consider include model placement during initial cool-down, maintaining placement during anticipated drag and lift forces, and force measurement. This later can be achieved by a passive technique, where the body is allowed to deflect under the influence of drag from its neutral position. The resulting shift in flux is detected via a superconducting pickup coil. The pickup coil may be connected either to a SQUID, or a secondary loop wound around a Hall probe. Both options are discussed. The objective of this work is to gain a better understanding of the nature of turbulent fields in normal and superfluid helium for potential application to problems in classical high Reynolds number turbulence.

Smith, Michael R.↗
NASA NTRS1997

Dynamics of Superfluid Helium in Low-Gravity

This report summarizes the work performed under a contract entitled 'Dynamics of Superfluid Helium in Low Gravity'. This project performed verification tests, over a wide range of accelerations of two Computational Fluid Dynamics (CFD) codes of which one incorporates the two-fluid model of superfluid helium (SFHe). Helium was first liquefied in 1908 and not until the 1930s were the properties of helium below 2.2 K observed sufficiently to realize that it did not obey the ordinary physical laws of physics as applied to ordinary liquids. The term superfluidity became associated with these unique observations. The low temperature of SFHe and it's temperature unifonrmity have made it a significant cryogenic coolant for use in space applications in astronomical observations with infrared sensors and in low temperature physics. Superfluid helium has been used in instruments such as the Shuttle Infrared Astronomy Telescope (IRT), the Infrared Astronomy Satellite (IRAS), the Cosmic Background Observatory (COBE), and the Infrared Satellite Observatory (ISO). It is also used in the Space Infrared Telescope (SIRTF), Relativity Mission Satellite formally called Gravity Probe-B (GP-B), and the Test of the Equivalence Principle (STEP) presently under development. For GP-B and STEP, the use of SFHE is used to cool Superconducting Quantum Interference Detectors (SQUIDS) among other parts of the instruments. The Superfluid Helium On-Orbit Transfer (SHOOT) experiment flown in the Shuttle studied the behavior of SFHE. This experiment attempted to get low-gravity slosh data, however, the main emphasis was to study the low-gravity transfer of SFHE from tank to tank. These instruments carried tanks of SFHE of a few hundred liters to 2500 liters. The capability of modeling the behavior of SFHE is important to spacecraft control engineers who must design systems that can overcome disturbances created by the movement of the fluid. In addition instruments such as GP-B and STEP are very sensitive to quasi-steady changes in the mass distribution of the liquid. The CFD codes were used to model the fluid's dynamic motion. Tests in one-g were performed with the main emphasis on being able to compute the actual damping of the fluid. A series of flights on the NASA Lewis reduced gravity DC-9 aircraft were performed with the Jet Propulsion Laboratory (JPL) Low Temperature Flight Facility and a superfluid Test Cell. The data at approximately 0.04g, lg and 2g were used to determine if correct fundamental frequencies can be predicted based on the acceleration field. Tests in zero gravity were performed to evaluate zero gravity motion.

Frank, David J.↗
NASA NTRS1996

Development of a High-Resolution, Single-Photon X-Ray Detector

Research on the development of a low-temperature, magnetic bolometer for x-ray detection is reported. The principal accomplishments during the first phase of this research are as follows. (1) We have constructed SQUID magnetometers and detected both 122 keV and 6 keV x-rays in relatively larger metallic samples with high quantum efficiency. (2) The magnetic properties of a metal sample with localized paramagnetic spins have been measured and found to agree with theoretical expectations. (3) The size of the magnetic response of the sample to x-rays is in agreement with predictions based on the properties of the sample and sensitivity of the magnetometer, supporting the prediction that a resolution of 1 eV at 10 keV should be achievable.

Seidel, George M.↗
NASA NTRS1960

Preliminary Investigation of a Paraglider

A preliminary investigation of the aerodynamic and control characteristics of a flexible glider similar to a parachute in construction has been made at the Langley Research Center to evaluate its capabilities as a reentry glider. Preliminary weight estimates of the proposed vehicle indicate that such a structure can be made with extremely low wing loading. Maximum temperatures during the reentry maneuver might be held as low as about 1,500 F. The results of wind-tunnel and free-glide tests show that the glider when constructed of nonporous material performed extremely well at subsonic speeds and could be flown at angles of attack from about 200 to 900. At supersonic speeds the wing showed none of the unfavorable tendencies exhibited by conventional parachutes at these speeds, such as squidding and breathing. Several methods of packing and deploying the glider have been successfully demonstrated. The results of this study indicate that this flexible-lifting-surface concept may provide a lightweight controllable paraglider for manned space vehicles.

Rogallo, Francis M.↗
NASA NTRS1997

High Resolution X-Ray Spectroscopy Using Microcalorimeters

During the past 13 years high resolution X ray spectrometers have been developed that use cryogenically cooled microcalorimeters. These devices have inherently high signal-to-noise by operating at temperatures below 0.1 K and can achieve an energy resolution of < 10 eV over the 0.1-10 keV band. Existing devices use doped semiconductor thermometers and typically employ HgTe absorbers. The energy resolution depends on achieving a low heat capacity for the device. For soft X ray applications a relatively thin absorber (approximately 1 micrometer) may be used and an energy resolution of approximately 7 eV has been achieved. For applications up to approximately 10 keV an absorber thickness of approximately 10 micrometer is required and the energy resolution is typically approximately 12 eV. Improvements to the energy resolution in this energy band could be achieved if the problems of thermalizing X rays in low heat capacity superconductors can be overcome. The recent work on transition edge thermometers by Irwin et nl. looks particularly promising because of the higher sensitivity achievable from a sharp superconducting transition. The relatively low impedance of such a device permits the use of a low noise SQUID amplifier for readout. This would also significantly reduce the cryogen heat load compared with JFETs required by higher impedance semiconductor thermometers.

Kelley, R. L.↗
NASA NTRS2000

The Fast Alternative Cryogenic Experiment Testbed

One of the challenges in the area of cryogenics for space exploration in the next millennium is providing the capability for inexpensive, frequent, access to space. Faced with this challenge during the International Space Station (ISS) build era, when other Space Shuttle manifesting opportunities are unavailable, a "proof of concept" cryostat has been developed to demonstrate the ability to accommodate low temperature science investigations within the constraints of the Hitchhiker siderail carrier. The Hitchhiker siderail carrier is available on a "mass available" basis during the ISS build era. In fact, several hitchhiker payloads flew with the deployment of the Unity module. Hitchhiker siderail carrier payloads have historically flown an average of about four times a year. A hybrid Solid Neon - Superfluid Helium cryostat has been developed with Janis Research Company to accommodate instruments of 16.5 cm diameter and 30 cm. length. This hybrid approach was taken in part to provide adequate on-orbit lifetime for instruments with high (conducted) heat loads from the instrumentation wiring. Mass, volume, lifetime and the launch hold scenario were all design drivers. In addition, with Ball Aerospace and Technologies Corporation, a multichannel VME architecture Germanium Resistance Thermometer (GRT) readout and heater control servo system has been developed. In a flight system, the cryostat and electronics payloads would be umbilically attached in a paired Hitchhiker siderail mount, and permit on-orbit command and telemetry capability. The results of performance tests of both the cryostat, and a helium sample instrument will be presented. The instrument features a self contained, miniaturized, nano-Kelvin resolution High Resolution Thermometer (HRT). This high level of thermal resolution is achieved through the utilization of a dc Superconducting Quantum Interference Device (SQUID). Although developed for the Low Temperature Microgravity Fundamental Physics investigator community, many design features are applicable in fields such as infrared and x-ray astronomy.

Nash, Alfred↗