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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Photonic methods and technologies for monitoring the ocean and atmosphere

In this paper, we review photonic methods and technologies that are promising for monitoring the ocean and atmosphere and have been implemented mainly in recent years at the Institute of Automation and Control Processes, Far Eastern Branch, Russian Academy of Sciences. We present results of lidar studies that have made it possible to understand key features of ocean – atmosphere interaction processes under continent – ocean transition conditions, which determine specific features of the atmospheric aerosol distribution, small gaseous components of the atmosphere and its optical characteristics. We consider methods and tools for combined optical and laser fluorescence monitoring of the ocean surface. Particular attention is paid to results of research on remote methods and tools for real-time laser-induced and laser fluorescence environmental monitoring of the ocean, including specialised fibre-optic probes and mobile underwater robotic systems. We present results of the development and investigation of highly sensitive, noise-proof fibre-optic hydro- and seismic/acoustic sensors for remote monitoring of the ocean and robotic systems for underwater laser protection of marine vessels, hydraulic structures and oceanographic instruments against the negative impact of biofouling. (invited paper)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Revealing symmetry-broken superconducting configurations by density functional theory

A coherent theory for the superconductivity of both conventional and unconventional superconductors is currently lacking. Here we show that superconductivity arises from the formation of a symmetry-broken superconducting configuration (SCC) due to atomic perturbation of the normal conducting configuration (NCC). This electron–phonon interaction creates straight one-dimensional tunnels (SODTs) for charge density of electrons and/or holes as revealed by the calculations based on density functional theory (DFT). The SODTs act as resistance-free superhighways and are correlated to the Cooper pairs in the Bardeen–Cooper–Schrieffer (BCS) theory. The formation of SODTs implies that the electron–phonon interaction in the BCS theory can be represented by the difference in charge densities between SCC and NCC predicted by DFT. The present work highlights that in conventional superconductors, SODTs are embedded within the bulk materials and are easily destroyed by phonon vibrations, resulting in a low critical superconducting temperature (T C ). Conversely, in unconventional superconductors such as YBa 2 Cu 3 O 7 (YBCO 7 ), SODTs are protected by a layered pontoon structure with very weak bonding to the bulk materials, maintaining SODTs’ stability at higher temperatures and leading to a much higher T C . The present approach is validated for 14 conventional superconductors of 18 pure elements and MgB 2 examined in this work, including the presently predicted superconductivity in Cu, Ag, Au, Sb, Bi, and MgB 2 at 0 K and 0 GPa, and one unconventional superconductor of YBCO 7 . Our discovery indicates that DFT can be a practical tool for predicting superconductors, enabling a systematic search for new superconducting materials in the future.

36 MATERIALS SCIENCE↗
NASA NTRS1971

A guide to onboard checkout. Volume 6: Structures/mechanics

The structures and mechanical subsystem of a space station are considered. The subsystem includes basic structure (pressurization, equipment support, meteoroid protection, radiators, insulation, and docking interfaces), the docking mechanisms, spacecraft access (hatches, airlocks, and view ports), and antenna deployment mechanisms. Checkout is discussed in terms of reliability, failure analysis, and maintenance.

Source record↗
NASA NTRS1973

Rotor burst protection program: Statistics on aircraft gas turbine engine failures that occurred in commercial aviation during 1971

A program to develop criteria for the design of devices that will be used on aircraft to protect passengers and the aircraft structure from the lethal and devastating fragments generated by the disintegration of a gas turbine engine rotor is discussed. Statistics on gas rotor turbine failures that have occurred in commercial aviation in 1971 are presented. It is shown that 124 rotor failures occurred and 35 of these were uncontained. This figure is considered significantly high to justify continuation of the development program.

Delucia, R. A.↗
NASA NTRS1979

Summary report of the Lightning and Static Electricity Committee

Lightning protection technology as applied to aviation and identifying these technology needs are presented. The flight areas of technical needs include; (1) the need for In-Flight data on lightning electrical parameters; (2) technology base and guidelines for protection of advanced systems and structures; (3) improved laboratory test techniques; (4) analysis techniques for predicting induced effects; (5) lightning strike incident data from General Aviation; (6) lightning detection systems; (7) obtain pilot reports of lightning strikes; and (8) better training in lightning awareness. The nature of each problem, timeliness, impact of solutions, degree of effort required, and the roles of government and industry in achieving solutions are discussed.

Plumer, J. A.↗
NASA NTRS1979

Lightning hazards overview: Aviation requirements and interests

A ten-year history of USAF lightning incidents is presented along with a discussion of the problems posed by lightning to current aircraft, and the hazards it constitutes to the electrical and electronic subsystems of new technology aircraft. Lightning technical protection technical needs, both engineering and operational, include: (1) in-flight data on lightning electrical parameters; (2) tech base and guidelines for protection of advanced systems and structures; (3) improved laboratory test techniques; (4) analysis techniques for predicting induced effects; (5) lightning strike incident data from general aviation; (6) lightning detection systems; (7) pilot reports on lightning strikes; and (8) better training in lightning awareness.

Corn, P. B.↗
NASA NTRS1980

Perspective on the results

The results of studies on the risk due to the use of carbon fibers in aircraft are assessed. Assumptions such as additional fire protection in the aircraft, new structural concepts, and the development of unique carbon composites are evaluated. Some findings from the national risk profile including equipment vulnerability and economic impact are discussed.

Huston, R. J.↗
NASA NTRS1980

Small Transport Aircraft Technology

The article surveys the results of the NASA-instituted Small Transport Aircraft Technology (STAT) research effort aimed at generating advanced technologies for application to new small, short haul transports having significantly better performance, efficiency, and environmental compatibility. Discussion covers fuselage designs and bonded aluminum-honeycomb wing construction which reduces the number of parts and fasteners, and gives a smoother outer contour. Topics discussed include: advanced aluminum alloys, composite primary structures, propellers, engine components, icing protection, avionics, flight controls, aerodynamics, and gust load alleviation.

Galloway, T. L.↗
NASA NTRS1980

The DOE photovoltaics program

As part of the National Solar Energy program, the US Department of Energy is now engaged in the development of technically feasible, low cost candidate component and system technologies to the point where technical readiness can be demonstrated by 1982. The overall strategy is to pursue parallel options that continue to show promise of meeting the program goals, thus increasing the probability that at least one technology will be successful. Included in technology development are both flat plate solar collectors and concentrator solar collectors, as well as the balance of system components, such as structures, power conditioning, power controls, protection, and storage. Generally, these last items are common to both flat plate and concentrator systems, but otherwise there is considerable disparity in design philosophy, photovoltaic cell requirements, and possible applications between the two systems. Objectives for research activities at NASA Lewis for stand alone applications, and at Sandia Laboratories where intermediate load center applications are addressed, are highlighted as well as college projects directed by Oak Ridge National Laboratory, and international applications managed by the Solar Energy Research Institute. Joint DOD/DOE effects for military applications are also summarized.

Ferber, R. R.↗
NASA NTRS1980

Pyrotechnic shock at the orbiter/external tank forward attachment

During the initial certification test of the forward structural attachment of the space shuttle orbiter to the external tank, pyrotechnic shock from actuation of the separation device resulted in structural failure of the thermal protection tiles surrounding the attachment. Because of the high shock associated with the separation bolt, the development of alternative low shock separation designs was initiated. Two concepts that incorporate a 5.08 centimeter frangible nut as the release device were developed and tested.

Rogers, W. F.↗
NASA NTRS1985

Telescoping Shield for Point-Focusing Solar Concentrators

Telescoping shield normally stowed around solar receiver protects heat engine and supporting structure from overheating when concentrator aimed few degrees away from line to Sun. When extended, shield intercepts off center concentrated solar radiation. Heat spread out over thermally conductive shield and reradiated diffusely not to cause structural damage.

Argoud, M.↗
NASA NTRS1987

Performance comparisons of maneuvering vehicles returning from orbit

In the present study of maneuvering reentry vehicles employing skipping and gliding flight paths, attention is given to aerodynamic heating pulses during longitudinal flight and lateral maneuvers. While skipping vehicles can achieve longer ranges than gliding ones, the deceleration loads can be an order of magnitude higher and involve heating rates 4-5 times higher, even for shallow entries, therefore requiring much heavier structural components and heavier thermal protection systems than gliders. A total lateral range of 8000 km is noted to be achievable by a gliding aerodynamic maneuver involving a 90-deg turn initiated at entry.

Tauber, Michael E.↗
NASA NTRS1988

NASA HOST project overview

NASA's Hot Section Technology, or 'HOST', program has developed improved analytical models for the aerothermal environment, thermomechanical loading, material behavior, structural response, and service life of aircraft gas turbine engines' hot section components. These models, in conjunction with sophisticated computer codes, can be used in design analyses of critical combustor and turbine elements. Toward these ends, efforts were undertaken in instrumentation, combustion, turbine heat transfer, structural analysis, fatigue/fracture, and surface protection. Attention is presently given to the organization of HOST activities and their specific subject matter.

Sokolowski, D. E.↗
NASA NTRS1988

Cryogenic Insulation System

This invention relates to reusable, low density, high temperature cryogenic foam insulation systems and the process for their manufacture. A pacing technology for liquid hydrogen fueled, high speed aircraft is the development of a fully reusable, flight weight cryogenic insulation system for propellant tank structures. In the invention cryogenic foam insulation is adhesively bonded to the outer wall of the fuel tank structure. The cryogenic insulation consists of square sheets fabricated from an array of abutting square blocks. Each block consists of a sheet of glass cloth adhesively bonded between two layers of polymethacrylimide foam. Each block is wrapped in a vapor impermeable membrane, such as Kapton(R) aluminum Kapton(R), to provide a vapor barrier. Very beneficial results can be obtained by employing the present invention in conjunction with fibrous insulation and an outer aeroshell, a hot fuselage structure with an internal thermal protection system.

Davis, Randall C.↗
NASA NTRS1991

Diffusion mechanisms in Ir-coated Re for high-temperature, radiation-cooled rocket thrusters

Materials used for radiation-cooled rocket thrusters must be capable of surviving under extreme conditions of high temperatures and oxidizing environments. Thruster chambers were developed using chemical-vapor-deposited (CVD) Re coated with CVD Ir on the inside surface which is exposed to hot combustion gases. Ir serves as an oxidation barrier protecting the Re which maintains structural integrity at high temperatures. In order to predict and extend the performance limits of these Ir-coated Re thrusters, the diffusion kinetics of CVD materials at temperature are studied. Thruster end ring sections were examined using electron microprobe analysis both before and after exposure to high temperature vacuum environments. The resulting elemental maps for Re, Ir, and Mo in the near-surface region allow identification of diffusion mechanisms operating at these temperatures. Line scans for Ir and Re were fit using a diffusion model to extract relevant diffusion constants. The fastest diffusion process is seen to be grain boundary diffusion with Re diffusing down grain boundaries in the Ir overlayer. The measured dependence of the diffusion rate on temperature will allow prediction of operating lifetimes for these thrusters.

Hamilton, J. C.↗
NASA NTRS1991

Thin coatings for protecting titanium aluminides in high-temperature oxidizing environments

Titanium aluminides have high specific strengths at high temperatures but are susceptible to environmental attack. Their use in many aerospace applications would require that they be protected with coatings that, for structural efficiency, must be thin. It is conceivable that acceptable coatings might be found in several oxide systems, and consequently, oxide coatings of many compositions were prepared from sol-gels for study. Response-surface methodology was used to refine coating compositions and factorial experiments were used to develop coating strategies. Oxygen permeability diagrams of two-layer coatings for several oxide systems, an analysis of multiple-layer coatings on rough and polished surfaces, and modeling of the oxidation weight gain are presented.

Wiedemann, K. E.↗
NASA NTRS1998

Reusable Cryogenic Tank VHM Using Fiber Optic Distributed Sensing Technology

The reusable oxygen and hydrogen tanks are key systems for both the X-33 (sub-scale, sub-orbital technology demonstrator) and the commercial Reusable Launch Vehicle (RLV). The backbone of the X-33 Reusable Cryogenic Tank Vehicle Health Management (VHM) system lies in the optical network of distributed strain temperature and hydrogen sensors. This network of fiber sensors will create a global strain and temperature map for monitoring the health of the tank structure, cryogenic insulation, and Thermal Protection System. Lockheed Martin (Sanders and LMMSS) and NASA Langley have developed this sensor technology for the X-33 and have addressed several technical issues such as fiber bonding and laser performance in this harsh environment.

Bodan-Sanders, Patricia↗
NASA NTRS1999

Collaborative Analysis Tool for Thermal Protection Systems for Single Stage to Orbit Launch Vehicles

Presented is a design tool and process that connects several disciplines which are needed in the complex and integrated design of high performance reusable single stage to orbit (SSTO) vehicles. Every system is linked to every other system and in the case of SSTO vehicles with air breathing propulsion, which is currently being studied by the National Aeronautics and Space Administration (NASA); the thermal protection system (TPS) is linked directly to almost every major system. The propulsion system pushes the vehicle to velocities on the order of 15 times the speed of sound in the atmosphere before pulling up to go to orbit which results high temperatures on the external surfaces of the vehicle. Thermal protection systems to maintain the structural integrity of the vehicle must be able to mitigate the heat transfer to the structure and be lightweight. Herein lies the interdependency, in that as the vehicle's speed increases, the TPS requirements are increased. And as TPS masses increase the effect on the propulsion system and all other systems is compounded. To adequately determine insulation masses for a vehicle such as the one described above, the aeroheating loads must be calculated and the TPS thicknesses must be calculated for the entire vehicle. To accomplish this an ascent or reentry trajectory is obtained using the computer code Program to Optimize Simulated Trajectories (POST). The trajectory is then used to calculate the convective heat rates on several locations on the vehicles using the Miniature Version of the JA70 Aerodynamic Heating Computer Program (MINIVER). Once the heat rates are defined for each body point on the vehicle, then insulation thickness that are required to maintain the vehicle within structural limits are calculated using Systems Improved Numerical Differencing Analyzer (SINDA) models. If the TPS masses are too heavy for the performance of the vehicle the process may be repeated altering the trajectory or some other input to reduce the TPS mass.

Alexander, Reginald Andrew↗