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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 1,117 records · Page 62
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Recent Developments at the U.S. Navy Wave Energy Test Site.

The U.S. Navy’s Wave Energy Test Site (WETS) in Hawaii has hosted two wave energy conversion (WEC) devices since its June 2015 commissioning – the Fred. Olsen BOLT Lifesaver and the Northwest Energy Innovations (NWEI) Azura – each for two deployments. Several additional devices will be tested in the coming years, beginning with the Ocean Energy device in summer 2019. The Hawaii Natural Energy Institute (HNEI) provides research and logistics support to WETS. We will provide an overview of three major activities that we have recently undertaken in this capacity. First, we will discuss results from a project in which modifications were made to the hull and float of the Azura, aimed at improving power performance for a second WETS deployment. Second, HNEI undertook a redeployment of Lifesaver beginning in October 2018, with the dual intent of achieving improvements in reliability and power performance, while also conducting an important demonstration of the use of wave power for non-grid applications. HNEI partnered with the University of Washington to integrate their Adaptable Monitoring Package (AMP) into the hull of BOLT Lifesaver. Included for this deployment was a subsea inductive charging capability from WiBotic, Inc.. These systems are powered entirely by electricity generated by the Lifesaver itself. Finally, HNEI has undertaken design improvements for the deeper berth moorings at WETS, with principal engineering guidance from DNV GL. This has included extensive numerical analysis of strength and fatigue aimed at establishing moorings that can persist for as long as possible. The resulting design will be discussed.

Wave energy conversion devices, Alternative market↗
NASA NTRS2022

AMD Radeon e9173 Low Power PCIE GPU Single Event Effects Test Report

The AMD Radeon Embedded e9170 Graphics Processing Unit (GPU), notably the e9173 Peripheral Component Interconnect Express (PCIE) variant, is of interest to Artemis generation programs with requirements for graphics rendering, compute, artificial intelligence (Ai) with a constraints-requiring piece-part procurement and power consumption of less than 50W. In addition to collecting heavy ion data on this device, a secondary purpose of this test campaign was to validate video capture hardware and software workflows used with GPU, microprocessor and system-on-chip device testing. Five (5) test patterns from the NEPP Processor Enclave (NPE) test suite were used with the e9173. The test patterns covered the operating system’s (OS) idle contribution towards the cross section, matrix math using tensorflow-rocm, two artificial intelligence models developed at NASA GSFC, and an industry standard GPU benchmarking application called Mesa GLXGears.

NASA Technical Memorandum (TM) test report for pos↗
NASA NTRS2012

NASA Flexible Screen Propellant Management Device (PMD) Demonstration With Cryogenic Liquid

While evaluating various options for liquid methane and liquid oxygen propellant management for lunar missions, Innovative Engineering Solutions (IES) conceived the flexible screen device as a potential simple alternative to conventional propellant management devices (PMD). An apparatus was designed and fabricated to test flexible screen devices in liquid nitrogen. After resolution of a number of issues (discussed in detail in the paper), a fine mesh screen (325 by 2300 wires per inch) spring return assembly was successfully tested. No significant degradation in the screen bubble point was observed either due to the screen stretching process or due to cyclic fatigue during testing. An estimated 30 to 50 deflection cycles, and approximately 3 to 5 thermal cycles, were performed on the final screen specimen, prior to and between formally recorded testing. These cycles included some "abusive" pressure cycling, where gas or liquid was driven through the screen at rates that produced differential pressures across the screen of several times the bubble point pressure. No obvious performance degradation or other changes were observed over the duration of testing. In summary, it is felt by the author that these simple tests validated the feasibility of the flexible screen PMD concept for use with cryogenic propellants.

Wollen, Mark↗
DOE OSTI2014

Development and Testing of an Integrated Sandia Cooler Thermoelectric Device (SCTD).

This report describes a FY14 effort to develop an integrated Sandia Cooler T hermoelectric D evice (SCTD) . The project included a review of feasible thermoelectric (TE) cooling applications, baseline performance testing of an existing TE device, analysis and design development of an integrated SCTD assembly, and performance measurement and validation of the integrated SCTD prototype.

Johnson, Terry A.↗
DOE OSTI2023

Validating a Tethered Balloon System and Optical Technologies for Marine Wildlife Detection and Tracking

The interactions between marine wildlife and marine energy devices are not well understood, leading to regulatory delays for device deployments and testing. Technologies that enable marine wildlife observations can help to fill data gaps and reduce uncertainties about animal–device interactions. A validation test conducted in Galveston Bay near La Porte, Texas, in December 2022 used a technology package consisting of a tethered balloon system and three independent sensor systems, including three-band visible, eight-band multispectral, and single-band thermal to detect three marine-mammal-shaped surrogates. The field campaign aimed to provide an initial step to evaluating the use of the TBS and the effectiveness of the sensor suite for marine wildlife observations and detection. From 2 December to 7 December 2022, 6 flights were conducted under varying altitudes and environmental conditions resulting in the collection of 5454 images. A subset of the images was classified and analyzed with two collection criteria including Beaufort wind force scale and TBS altitude to assess a range of observations of a surrogate from near-shore to offshore based on pixel count. The results of this validation test demonstrate the potential for using TBSs and imaging sensors for marine wildlife observations and offer valuable information for further development and application of this technology for marine energy and other blue economy sectors.

47 OTHER INSTRUMENTATION↗
NASA NTRS1980

Comparison of several inflow control devices for flight simulation of fan tone noise using a JT15D-1 engine

The paper describes the tests of four devices intended to reduce inflow disturbances and turbulences using a JT15D-1 turbofan engine. The tests were made to simulate the in-flight fan tone noise; the inflow control devices (ICD's) consisted of honeycomb/screen structures mounted over the engine inlet. The ICD's ranged from 1.6 to 4 fan diameters in size, and were made with several fabrication methods. All the ICD's significantly reduced the BPF tone in the far-field directivity patterns, but the smallest ICD's introduced propagating modes which could be recognized by additional lobes in the patterns. The JT15D-1 engine had a tone source which generated a strong propagating mode at fan speeds corresponding to 'approach' power and higher. Data from a typical transducer showed that the unsteady inflow distortion modes were eliminated or reduced when either of the ICD's was installed.

Mcardie, J. G.↗
DOE OSTI2013

Electroluminescence and Transmission Electron Microscopy Characterization of Reverse-Biased AlGaN/GaN Devices

Reverse-bias stress testing has been applied to a large set of more than 50 AlGaN/GaN high electron mobility transistors, which were fabricated using the same process but with different values of the AlN mole fraction and the AlGaN barrier-layer thickness, as well as different substrates (SiC and sapphire). Two sets of devices having different defect types and densities, related to the different growth conditions and the choice of nucleation layer, were also compared. When subjected to gate drain (or gate-to-drain and source short-circuited) reverse-bias testing, all devices presented the same time-dependent failure mode, consisting of a significant increase in the gate leakage current. This failure mechanism occurred abruptly during step-stress experiments when a certain negative gate voltage, or critical voltage, was exceeded or, during constant voltage tests, at a certain time, defined as time to breakdown. Electroluminescence (EL) microscopy was systematically used to identify localized damaged areas that induced an increase of gate reverse current. This current increase was correlated with the increase of EL intensity, and significant EL emission during tests occurred only when the critical voltage was exceeded. Focused-ion-beam milling produced cross-sectional samples suitable for electron microscopy observation at the sites of failure points previously identified by EL microscopy. In highdefectivity devices, V-defects were identified that were associated with initially high gate leakage current and corresponding to EL spots already present in untreated devices. Conversely, identification of defects induced by reverse-bias testing proved to be extremely difficult, and only nanometer-size cracks or defect chains, extending vertically from the gate edges through the AlGaN/GaN heterojunction, were found. No signs of metal/semiconductor interdiffusion or extended defective areas were visible.

Cullen, David A↗
DOE OSTI2012

Improved Production and Separation Technologies for Non-standard PET Radionuclides

Brief summary of activity issues, concerns, successes: Project 1 is completed. We have optimized plating parameters with the new target bodies and slanted target plating system. The target station has been mounted on the end of the beamline, service lines have been Installed to allow for helium and water cooling. We have routinely produced copper-64 using the new slanted target system in conjunction with our automated system. In project 2, we successfully fabricated and tested microfluidic extraction devices made out of two organic solvent-resistant polymers, thiolene and SIFEL. Initially, we developed analytical and computational models to describe the extraction process, and used the model to design the microfluidic devices. Then we optimized the microfabrication procedures to manufacture microreactors, followed by optimization of the operational parameters to obtain a stable aqueous-organic interface, which is critical for efficient extraction. When we tested the thiolene devices for extraction of copper-64, we observed very low extraction efficiencies (less than 5%) due to adhesion of copper to thiolene. However, we observed very high extraction efficiencies with SIFEL devices (greater than 95%), which are due to the high interfacial area for extraction and shorter diffusion lengths.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2024

Catalyst-Specific Accelerated Stress Tests in Proton Exchange Membrane Low-Temperature Electrolysis for Intermittent Operation

Device-level stress tests are developed that focus on anode catalyst layer degradation and future anticipated operating conditions, including intermittent load and reduced platinum group metal content. Square-wave cycles with an upper load limit of 2.5 A cm -2 are utilized to screen commercial iridium (Ir) materials. Performance losses are primarily due to decreasing kinetics and are accompanied by catalyst migration into the membrane, worsening catalyst/ionomer integration, and weakening of the catalyst/membrane interface. For ruthenium-containing catalysts, the in situ performances are higher but durabilities lower than Ir baselines, and any performance advantage is lost within the test. Increased loss is likely due to the higher dissolution rate; microscopy confirmed greater degrees of ruthenium migration. For Ir metal or mixed oxides, ex situ activity improvements generally did not translate to in situ performance. The durability, however, is significantly lower and the loss rate increased from 3 (oxide) to 9 (metal) μ V cycle -1 . These results are consistent with historical findings in literature, rationalize the continued use of iridium oxide as a baseline catalyst, and demonstrate that traditional catalyst development approaches may not improve device-level durability when focused on low-cost applications. A shift in focus may therefore be more effective at improving catalyst utilization and lessening load requirements.

08 HYDROGEN↗
DOE OSTI2019

Interaction of Water with Carbon Fiber Reinforced Polymer Laminates under Dynamic Loading Conditions

With the aim of simulating the real conditions during the navigation, in this framework, impact tests were performed by loading CFRP laminates immersed in the water from the front side. The specimens, made by vinyl ester matrix because of the lower moisture absorption compared to the other epoxy systems, are in the presence of the water to accurately simulate the incidental impact on the hull of the vessel, immersed or partially immersed, during the navigation. It can be caused by the ice in the Arctic Ocean, by a projectile due to a terroristic attack or by debris from an explosion. The results are compared with the ones obtained by loading the laminates in pure traditional impact tests in the air. The influence of the clamping device has been tested too. The exciting results obtained on carbon fiber laminates in the air (pure traditional impact tests), water-backed (with water on the back side) and waterfront (water only on the front side) conditions at room temperature are here reported and compared. They highlighted the critical role played by the complex fluid–structure interaction.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Reverse-Bias Resilience of Monolithic Perovskite/Silicon Tandem Solar Cells

Metal halide perovskites have rapidly enabled a range of high-performance photovoltaic technologies. However, catastrophic failure under reverse voltage bias hinders their commercialization. In this work, we demonstrate that by employing a monolithic perovskite/silicon tandem structure, the perovskite subcell can be effectively protected by the silicon subcell under reverse bias, owing to the low reverse-bias diode current of the silicon subcell. As a result, the tested perovskite/silicon tandem devices show superior reverse-bias resilience compared to perovskite single-junction devices in both long-term reverse voltage biasing tests at the single-cell level and partial shading tests at the module level. These results highlight that, compared to other perovskite technologies, monolithic perovskite/silicon tandems are at a higher technology readiness level in terms of tackling the reverse-bias and partial shading challenge, which is a considerable advantage towards commercialization.

commercialization↗
NASA NTRS1980

JANTX2N2219A dual transistor

Report describes effects of power and temperature overstress on Texas Instruments and National Semiconductor devices. Texas Instruments devices had only two failures in 2500 hours of testing. National Semiconductor devices reached 50% failure limit. No consistent failure mode was detected.

Source record↗
NASA NTRS1992

Control of unsteady separated flow associated with the dynamic stall of airfoils

The two principal objectives of this research were to achieve an improved understanding of the mechanisms involved in the onset and development of dynamic stall under compressible flow conditions, and to investigate the feasibility of employing adaptive airfoil geometry as an active flow control device in the dynamic stall engine. Presented here are the results of a quantitative (PDI) study of the compressibility effects on dynamic stall over the transiently pitching airfoil, as well as a discussion of a preliminary technique developed to measure the deformation produced by the adaptive geometry control device, and bench test results obtained using an airfoil equipped with the device.

Wilder, Michael C.↗
NASA NTRS2014

Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMDs), such as screen channel capillary liquid acquisition devices (LADs), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity these results to flow rate and tank internal pressure.

Liquid Oxygen↗
NASA NTRS2014

Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMD's), such as screen channel capillary liquid acquisition devices (LAD's), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity of these results to flow rate and tank internal pressure.

Microgravity↗
DOE OSTI2015

A novel tensile device for in situ scanning electron microscope mechanical testing

To facilitate the study of deformation mechanisms and mechanical properties of bulk materials with feature size of centimeter level, a novel tensile device compatible with scanning electron microscope (SEM) was designed and built. Integrating the servo motor and three-stage reducer, the device could realize quasistatic loading mode with a loading speed of 10 nm/s. The device also presents broad compatibility with various types of SEMs due to its miniaturized dimensions and larger volume–output load ratio compared with existing and commercial tensile instruments. A small lead precise ball screw with left- and right-hand thread was adopted to keep the center of the specimen remain stationary without moving during the tensile testing. A novel gripping method was carefully taken into account to guarantee the alignment issues. The closed-loop control mode of the tensile process was developed. The displacement resolution of 40 nm was tested to verify the driving performance of the device. Furthermore, correction method on testing displacement was investigated based on the calibration experiments of the load sensor and displacement sensor, and the comparison tests based on stress–strain curve were carried out between the self-made device and the commercial tensile instrument (Instron 3345) to verify the feasibility and universality of the correction method.

36 MATERIALS SCIENCE↗