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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Contrast analysis in two-beam laser interference lithography

Interference lithography enables large area, sub-µm, periodic patterning without photomasks or projection lithography tools. We show that optical contrast, which is the fundamental design variable of interference lithography, enforces coupled constraints on source coherence, beam pointing stability, field size, polarization state, and the intensity balance between beams. The analysis enables selection and alignment tolerance of components to meet a specific design requirement. In particular, the analysis reveals that grating beam splitters are significantly less sensitive to beam pointing and polarization misalignment than plate beam splitters.

Miller, David B. (ORCID:0000000207755284)↗
DOE OSTI2014

Definition of Capabilities Needed for a Single Event Effects Test Facility

The Federal Aviation Administration (FAA) is contemplating new regulations mandating testing of the vulnerability of flight-critical avionics to single event effects (SEE). A limited number of high-energy neutron test facilities currently serve the SEE industrial and institutional research community. The FAA recognizes that existing facilities have insufficient test capacity to meet new demand from such mandates; it desires more flexible irradiation capabilities to test complete, large systems and would like capabilities to address greater concerns for thermal neutrons. For this reason, the FAA funded this study by Spallation Neutron Source (SNS) staff with the ultimate aim of developing options for SEE test facilities using high-energy neutrons at the SNS complex. After an investigation of current SEE test practices and assessment of future testing requirements, three concepts were identified covering a range of test functionality, neutron flux levels, and fidelity to the atmospheric neutron spectrum. The costs and times required to complete each facility were also estimated. SEE testing is generally performed by accelerating the event rate to a point where the effects are still dominated by single events and double event causes of failures are negligible. In practice, acceleration factors of as high as 10 6 are applicable for component testing, whereas for systems testing acceleration factors of 10 4 seem to be the upper limit. It is strongly desirable that the irradiation facility be tunable over a large range of high-energy neutron fluxes of 10 2 - 10 4 n/cm²/s for systems testing and from 10 4 - 10 7 n/cm²/s for components testing. The most capable, most flexible, and highest-test-capacity option is a new stand-alone target station named the High-Energy neutron Test Station (HETS). It is also the most expensive option, with a cost to complete of approximately $100 million. Dual test enclosures would allow for simultaneous testing activity effectively doubling overall test capacity per HETS operating hour. Using about 1 kilowatt (kW) of proton power extracted from the accelerator before injection in the accumulator ring, its operation would be unnoticeable by neutron scattering users at the SNS target station. The H beam laser stripping technique would allow for control of beam power on the HETS target independent from power delivered to the SNS. Large systems with frontal areas of up to 1 x 2 m² could be accommodated with integral high-energy flux values (above 10 megaelectron-volt, or MeV) to at most 10 4 n/cm²/s; components could also be tested with flux levels to at most 10 7 n/cm²/s on beam sizes of up to 0.2 x 0.2 m². Selectable moderating material and neutron filters would allow tailoring of the neutron spectrum to user demands; charged particle deflectors could be switched to allow or deflect protons, pions, and muons. It is estimated that HETS would take 5 years to complete after award of contract, including engineering design and construction. Commissioning would take at least another 6 months. Interference with SNS principal operations was not considered in the construction time estimate; connection of the proton transport line and tunnel from the accelerator high energy beam transport (HEBT) and construction around existing site utilities would require careful planning and coordination with beam operations at the SNS. A high-energy (HE) neutron test facility using an available beam line on the SNS target station is a technically and financially attractive option. Inspired by the new ChipIR instrument on the ISIS TS 2 spallation source in the UK, a similar facility could be placed on an unused beam line in the SNS instrument hall [e.g., on beam line 8 (both A and B channels would be needed) or on beam line 10]. The performance would approach that of an HETS (~80%), but it would be operationally more limited, with only a single user at a time. Space is more limited, so the maximum system size would be about half of that in an HETS. Flexibility to tailor the spectrum would be somewhat more limited. While this concept was not as fully developed and characterized, preliminary work indicates very high HE flux levels should be possible, with ample thermal neutrons as well. Flux control would be more difficult than at HETS because proton power on target be whatever the SNS was operating at for neutron scattering. Neutron attenuation devices would have to be employed with as-yet undetermined control resolution. However, no new buildings would be needed, and the necessary utilities are already present in the SNS Experiment Hall. The estimated cost for a beam line option is around $15 million; the time to complete would be 3 years after award of contract, plus at least 6 months for commissioning. Interference of construction activities with SNS operations should be negligible. This option would require negotiation with the Department of Energy Basic Energy Sciences (BES) office -- the primary stakeholder of SNS -- for an application outside the usual scope of neutron scattering sciences. Furthermore, these presently open beam lines are highly desirable locations for proposed neutron scattering instruments and obtaining one of them for an SEE test facility will come only with persuasive and timely arguments to SNS leadership and the DOE BES. The third option is a tunnel extension/target cave facility providing the most basic system-level irradiation capability with minimal flexibility. Again not as well developed a concept as HETS, it would use a laser-stripping technique like an HETS, redirecting protons to a tunnel similar to the initial HETS proton transport tunnel. Indeed, this concept is intended to be upgradable to a full HETS facility. Only a small fraction of a watt of proton power would be used in this basic configuration, though. An uncooled target and primitive shielding arrangement would provide beam on modestly sized systems that must be placed in close proximity to the target. The neutron fluence would be less uniform over the system than with the HETS or the beam line option. A data acquisition room and support area would be located on the ground level; access to the target cave would be via elevator and/or stairway. As a result of the required excavation, new tunnel construction, shielding, data acquisition building, utilities, and other items, the estimated cost is $30 million. The time to complete is expected be more than 3 years; here again construction interference with SNS operations has not been accounted for, but it could have a significant impact.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Component Test Facility (Comtest) Phase 1 Engineering For 760°C (1400°F) Advanced Ultrasupercritical (A-USC) Steam Generator Development

The Babcock & Wilcox Company (B&W) performed a Pre-Front End Engineering Design (Pre-FEED) of an A-USC steam superheater for a proposed component test program achieving 760°C (1400°F) steam temperature. This would lead to follow-on work in a Phase 2 and Phase 3 that would involve detail design, manufacturing, construction and operation of the ComTest. Phase 1 results have provided the engineering data necessary for proceeding to the next phase of ComTest. The steam generator superheater would subsequently supply the steam to an A-USC prototype intermediate pressure steam turbine. The ComTest program is important in that it will place functioning A-USC components in operation and in coordinated boiler and turbine service. It is also important to introduce the power plant operation and maintenance personnel to the level of skills required and provide the first background experience with hands-on training. The project will provide a means to exercise the complete supply chain events required in order to practice and perfect the process for A-USC power plant design, supply, manufacture, construction, commissioning, operation and maintenance. Representative participants will then be able to transfer knowledge and recommendations to the industry. ComTest is conceived in the manner of using a separate standalone plant facility that will not jeopardize the host facility or suffer from conflicting requirements in the host plant’s mission that could sacrifice the nickel alloy components and not achieve the testing goals. ComTest will utilize smaller quantities of the expensive materials and reduce the risk in the first operational practice for A-USC technology in the United States. Components at suitable scale in ComTest provide more assurance before putting them into practice in the full size A-USC demonstration plant.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2016

Affordable Hybrid Heat Pump Clothes Dryer

This project was successful in demonstrating the feasibility of a step change in residential clothes dryer energy efficiency by demonstrating heat pump technology capable of 50% energy savings over conventional standard-size electric dryers with comparable drying times. A prototype system was designed from off-the-shelf components that can meet the project’s efficiency goals and are affordable. An experimental prototype system was built based on the design that reached 50% energy savings. Improvements have been identified that will reduce drying times of over 60 minutes to reach the goal of 40 minutes. Nevertheless, the prototype represents a step change in efficiency over heat pump dryers recently introduced to the U.S. market, with 30% improvement in energy efficiency at comparable drying times.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Status update on the US ODS development program

Three papers are attached highlighting some recent progress in the development and testing of Oxide Dispersion Strengthened ferritic steels in tube and plate form. Aydogan et al. (2016) and Alam et al. (2016) papers summarize testing and characterization that has been performed on plate and tube materials. In the Alam et al. paper it was noted that after cross-rolling plate material of 14YWT, microcracks were formed. This resulted from an (001) texture in the plane normal to the plate causing cracking microcracking within that plane. Such microcracking affects low temperature tensile properties up to 200C. It was not seen in tube material produced by hydrostatic extrusion. In the Aydogan et al. (2016) paper characterization was performed on tubes produced from the ODS material, 14YWT. Tubes were formed through hydrostatic extrusion of plate material and hydrostatic extrusion of spray formed tubes. It was noted that strong texture on {001}<110> was formed in the plate material while shear deformation during hot extrusion produced a strong <111> ll ND texture component. In the Aydogan et al. (2017) paper detailed analysis was performed on the change in oxide size with ion irradiation to doses >500 dpa at 450C. The results show strong stability for the 2-4 nm oxide particles with a reduction in size ~25% after 270 dpa and an increase in density.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1973

Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept

A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

Taylor, M. F.↗
NASA NTRS1977

Characteristics of southern hemisphere 200-mbar flow as determined from satellite data

Characteristics of southern hemisphere (SH) 200-mbar flow are examined by using geopotential height fields constructed with the aid of a satellite-based thermal structure. Similar northern hemisphere (NH) satellite-based fields are developed in order to make interhemispheric comparisons. Results indicate that both zonal and meridional components of the SH eddy kinetic energy are as large as their NH counterparts. The SH flow is in general more dependent on transient eddies, especially with regard to the meridional flow. In winter the difference in standing eddy magnitude is apparent only in the north-south component. In summer both zonal and meridional components have smaller standing eddy contributions in the SH. The meridional spectra show a preference for intermediate size (k = 4, 5) transient waves. Ratios of zonal to meridional energies indicate that, especially at intermediate wavelengths, the SH waves are 'more meridional' than those in the NH.

Adler, R. F.↗
NASA NTRS1982

Martian dust mantling and surface composition - Interpretation of thermophysical properties

The goal of the study presented here is to use the diurnal variation of the differences in the brightness temperatures between each of the four surface-sensing IRTM (infrared thermal mapper) wavelength bands to separate the average grain size determined by the thermal inertia into the surface block population and the inertia of the fine component. It is noted that the thermal emissivity of the surface can also be determined and that this in turn can be used to estimate compositional variations. What is more, the atmospheric dust content can be estimated and used to infer sources and sinks of airborne dust. Owing to the number of unknowns, observations at more than one time of day are necessary to determine each of these parameters independently. The data discussed here were obtained by the IRTM, which had five thermal channels centered at 7, 9, 11, 15, and 20 microns and one channel that measured solar reflectance for from 0.3 to 3.0 microns.

Christensen, P. R.↗
NASA NTRS1988

Catalog of open clusters and associated interstellar matter

The Catalog of Open Clusters and Associated Interstellar Matter summarizes observations of 128 open clusters and their associated ionized, atomic, and molecular iinterstellar matter. Cluster sizes, distances, radial velocities, ages, and masses, and the radial velocities and masses of associated interstellar medium components, are given. The database contains information from approximately 400 references published in the scientific literature before 1988.

Leisawitz, David↗
NASA NTRS1994

VLSI technology for smaller, cheaper, faster return link systems

Very Large Scale Integration (VLSI) Application-specific Integrated Circuit (ASIC) technology has enabled substantially smaller, cheaper, and more capable telemetry data systems. However, the rapid growth in available ASIC fabrication densities has far outpaced the application of this technology to telemetry systems. Available densities have grown by well over an order magnitude since NASA's Goddard Space Flight Center (GSFC) first began developing ASIC's for ground telemetry systems in 1985. To take advantage of these higher integration levels, a new generation of ASIC's for return link telemetry processing is under development. These new submicron devices are designed to further reduce the cost and size of NASA return link processing systems while improving performance. This paper describes these highly integrated processing components.

Nanzetta, Kathy↗
NASA NTRS2004

Design Space Issues for Intrinsic Evolvable Hardware

This paper discusses the problem of increased programming time for intrinsic evolvable hardware (EM) as the complexity of the circuit grows. As the circuit becomes more complex, then more components will be required and a longer programming string, L, is required. We develop equations for the size of the population, n, and the number of generations required for the population to converge, based on L. Our analytical results show that even though the design search space grows as 2L (assuming a binary programming string), the number of circuit evaluations, n*ngen, only grows as O(Lg3), or slightly less than O(L). This makes evolvable techniques a good tool for exploring large design spaces. The major hurdle for intrinsic EHW is evaluation time for each possible circuit. The evaluation time involves downloading the bit string to the device, updating the device configuration, measuring the output and then transferring the output data to the control processor. Each of these steps must be done for each member of the population. The processing time of the computer becomes negligible since the selection/crossover/mutation steps are only done once per generation. Evaluation time presently limits intrinsic evolvable hardware techniques to designing only small or medium-sized circuits. To evolve large or complicated circuits, several researchers have proposed using hierarchical design or reuse techniques where submodules are combined together to form complex circuits. However, these practical approaches limit the search space of available designs and preclude utilizing parasitic coupling or other effects within the programmable device. The practical approaches also raise the issue of why intrinsic EHW techniques do not easily apply to large design spaces, since the analytical results show only an O(L) complexity growth.

Hereford, James↗
NASA NTRS2004

Integrity of Ceramic Parts Predicted When Loads and Temperatures Fluctuate Over Time

Brittle materials are being used, and being considered for use, for a wide variety of high performance applications that operate in harsh environments, including static and rotating turbine parts for unmanned aerial vehicles, auxiliary power units, and distributed power generation. Other applications include thermal protection systems, dental prosthetics, fuel cells, oxygen transport membranes, radomes, and microelectromechanical systems (MEMS). In order for these high-technology ceramics to be used successfully for structural applications that push the envelope of materials capabilities, design engineers must consider that brittle materials are designed and analyzed differently than metallic materials. Unlike ductile metals, brittle materials display a stochastic strength response because of the combination of low fracture toughness and the random nature of the size, orientation, and distribution of inherent microscopic flaws. This plus the fact that the strength of a component under load may degrade over time because of slow crack growth means that a probabilistic-based life-prediction methodology must be used when the tradeoffs of failure probability, performance, and useful life are being optimized. The CARES/Life code (which was developed at the NASA Glenn Research Center) predicts the probability of ceramic components failing from spontaneous catastrophic rupture when these components are subjected to multiaxial loading and slow crack growth conditions. Enhancements to CARES/Life now allow for the component survival probability to be calculated when loading and temperature vary over time.

Nemeth, Noel N.↗
NASA NTRS1995

(abstract) Vibration Damping of the Cassini Spacecraft Structure

Cassini will be protected during launch ascent through the atmosphere by a lightweight aluminum payload fairing (PLF). As a result of the extreme noise levels generated by the powerful Titan IV at liftoff, and the acoustic transparency of the PLF, Cassini is predicted to experience severe acoustic levels. Furthermore, the high acoustic levels, coupled with the size and configuration of the spacecraft, will induce intense random vibration on the structure and critical spacecraft components. Efforts to mitigate the vibroacoustic environment by modifying the spacecraft structure were pursued. Preliminary studies indicated that a structural damping treatment using viscoelastic materials (VEMs) represented a viable technique of reducing vibration with minimum impact on weight, cost, and redesign. Tuned Vibration Absorbers (TVAs) - compact, single degree-of-freedom mechanical oscillators in which a VEM serves as the spring and damping element - will be used also. The operating principles, design, and installation of the TVAs are described, the test program is outlined, and test results are presented which show that significant vibration attenuation was achieved.

vibroacoustic environment↗
NASA NTRS2006

Observing Ice in Clouds from Space

There are many satellite observations of cloud top properties and the liquid and rain content of clouds, however, we do not yet quantitatively understand the processes that control the water budget of the upper troposphere where ice is the predominant phase, and how these processes are linked to precipitation processes and the radiative energy budget. The ice in clouds in the upper troposphere either melts into rain or is detrained, and persists, as cirrus clouds affecting the hydrological and energy cycle, respectively. Fully modeling the Earth's climate and improving weather and climate forecasts requires accurate satellite measurements of various cloud properties at the temporal and spatial scales of cloud processes. These properties include cloud horizontal and vertical structure, cloud water content and some measure of particle sizes and shapes. The uncertainty in knowledge of these ice characteristics is reflected in the large discrepancies in model simulations of the upper tropospheric water budget. Model simulations are sensitive to the partition of ice between precipitation and outflow processes, i.e., to the parameterization of ice clouds and ice processes. One barrier to achieving accurate global ice cloud properties is the lack of adequate observations at millimeter and submillimeter wavelengths (183-874 GHz). Recent advances in instrumentation have allowed for the development and implementation of an airborne submillimeter-wave radiometer. The brightness temperatures at these frequencies are especially sensitive to cirrus ice particle sizes (because they are comparable to the wavelength). This allows for more accurate ice water path estimates when multiple channels are used to probe into the cloud layers. Further, submillimeter wavelengths offer simplicity in the retrieval algorithms because they do not probe into the liquid and near surface portions of clouds, thus requiring only one term of the radiative transfer equation (ice scattering) to relate brightness temperatures to ice. The next step is a satellite mission designed to acquire global Earth radiance measurements in the submillimeter-wave region, thus bridging the measurement gap between microwave sounders and shorter-wavelength infrared and visible sensors. This presentation provides scientific justification and an approach to measuring ice water path and particle size from a satellite platform that spans a range encompassing both the hydrologically active and radiatively active components of cloud systems.

Ackerman, S.↗
NASA NTRS2010

NDARC - NASA Design and Analysis of Rotorcraft Validation and Demonstration

Validation and demonstration results from the development of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are presented. The principal tasks of NDARC are to design a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft chosen as NDARC development test cases are the UH-60A single main-rotor and tail-rotor helicopter, the CH-47D tandem helicopter, the XH-59A coaxial lift-offset helicopter, and the XV-15 tiltrotor. These aircraft were selected because flight performance data, a weight statement, detailed geometry information, and a correlated comprehensive analysis model are available for each. Validation consists of developing the NDARC models for these aircraft by using geometry and weight information, airframe wind tunnel test data, engine decks, rotor performance tests, and comprehensive analysis results; and then comparing the NDARC results for aircraft and component performance with flight test data. Based on the calibrated models, the capability of the code to size rotorcraft is explored.

Johnson, Wayne↗
NASA NTRS2011

Particle Trajectory and Icing Analysis of the E(sup 3) Turbofan Engine Using LEWICE3D Version 3

Particle trajectory and ice shape calculations were made for the Energy Efficient Engine (E(sup 3)) using the LEWICE3D Version 3 software. The particle trajectory and icing computations were performed using the new "block-to-block" collection efficiency method which has been incorporated into the LEWICE3D Version 3 software. The E(sup 3) was developed by NASA and GE in the early 1980 s as a technology demonstrator and is representative of a modern high bypass turbofan engine. The E(sup 3) flow field was calculated using the NASA Glenn ADPAC turbomachinery flow solver. Computations were performed for the low pressure compressor of the E(sup 3) for a Mach 0.8 cruise condition at 11,887 m assuming a standard warm day for three drop sizes and two drop distributions typically used in aircraft design and certification. Particle trajectory computations were made for water drop sizes of 5, 20, and 100 microns. Particle trajectory and ice shape predictions were made for a 20 micron Langmuir-D distribution and for a 92 mm Super-cooled Large Droplet (SLD) distribution with and without splashing effects for a Liquid Water Content (LWC) of 0.3 g/cu m and an icing time of 30 min. The E3 fan and spinner combination proved to be an effective ice removal mechanism as they removed greater than 36 percent of the mass entering the inlet for the icing cases. The maximum free stream catch fraction for the fan and spinner combination was 0.60 while that on the elements downstream of the fan was 0.03. The non-splashing trajectory and collection efficiency results showed that as drop size increased impingement rates increased on the spinner and fan leaving less mass to impinge on downstream components. The SLD splashing case yielded more mass downstream of the fan than the SLD non-splashing case due to mass being splashed from the upstream inlet lip, spinner and fan components. The ice shapes generated downstream of the fan were either small or nonexistent due to the small available mass and evaporation except for the 92 m SLD splashing case. Relatively large ice shapes were predicted for internal guide vane #1 and rotor #1 for the 92 m SLD splashing case due to re-impingement of splashed mass.

Bidwell, Colin S.↗
NASA NTRS2012

Evaluating Suit Fit Using Performance Degradation

The Mark III planetary technology demonstrator space suit can be tailored to an individual by swapping the modular components of the suit, such as the arms, legs, and gloves, as well as adding or removing sizing inserts in key areas. A method was sought to identify the transition from an ideal suit fit to a bad fit and how to quantify this breakdown using a metric of mobility-based human performance data. To this end, the degradation of the range of motion of the elbow and wrist of the suit as a function of suit sizing modifications was investigated to attempt to improve suit fit. The sizing range tested spanned optimal and poor fit and was adjusted incrementally in order to compare each joint angle across five different sizing configurations. Suited range of motion data were collected using a motion capture system for nine isolated and functional tasks utilizing the elbow and wrist joints. A total of four subjects were tested with motions involving both arms simultaneously as well as the right arm by itself. Findings indicated that no single joint drives the performance of the arm as a function of suit size; instead it is based on the interaction of multiple joints along a limb. To determine a size adjustment range where an individual can operate the suit at an acceptable level, a performance detriment limit was set. This user-selected limit reveals the task-dependent tolerance of the suit fit around optimal size. For example, the isolated joint motion indicated that the suit can deviate from optimal by as little as -0.6 in to -2.6 in before experiencing a 10% performance drop in the wrist or elbow joint. The study identified a preliminary method to quantify the impact of size on performance and developed a new way to gauge tolerances around optimal size.

Margerum, Sarah E.↗