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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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The shear punch testing of irradiated and control MA956 (FeCrAl) Alloy from the NSUF-ATR-UCSB irradiation is presented. This is the first data taken on a new shear punch fixture design to test three 1.5mm punches from each 8mm x 0.5mm Disc Multipurpose Coupon (DMC). Samples were irradiated to 6.1dpa at a temperature of 315°C and 6.2 dpa at 400°C.
A novel combination of diagnostics is being used to research the physics of detonator initiation. The explosive PETN (Pentaerythritol tetranitrate) commonly used in detonators, is also a piezo-electric material that, when sufficiently shocked, emits an electromagnetic field in the radio frequency (RF) range, along crystal fracture planes. In an effort to capture this RF signal, a new diagnostic was created. A copper foil, used as an RF antenna, was wrapped around a foam fixture encompassing a PETN pellet. Rogowski coils were used to obtain the change in current with respect to time (di/dt) the detonator circuit, in and polyvinylidene difluoride (PVDF) stress sensors were used to capture shockwave arrival time. The goal of these experiments is to use these diagnostics to study the reaction response of a PETN pellet of known particle size to shock loading with various diagnostics including an antenna to capture RF emissions. Our hypothesis is that RF feedback may signify the rate of deflagration to detonation transition (DDT) or lack thereof. The new diagnostics and methods will be used to determine the timing of start of current, bridge burst, detonator breakout timing and RF generated from detonation. These data will be compared to those of currently used diagnostics in order to validate the accuracy of these new methods. Future experiments will incorporate other methods of validation including dynamic radiography, optical initiation and use of magnetic field sensors.
To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. The hazard presented by liquid fuels, such as gasoline and diesel, results from the spillage of these liquids and subsequent ignition of vapors, causing a fire or explosion. Facilities that maintain liquid-fueled vehicles and implement appropriate safety measures are protected with ventilation systems designed to capture liquid fuel vapors at or near floor level. To minimize the potential for ignition in the event of a spill, receptacles, electrical fixtures, and hot-work operations, such as welding, are located outside of these areas. Compressed natural gas (CNG) is composed of methane with slight amounts of heavier simple hydrocarbons. Maintenance facilities that maintain CNG vehicles indoors must be protected against fire and explosion. However, the means of ensuring safety are different from those employed for liquid fuels because of the gaseous nature of methane and the fact that it is lighter than air. Because CNG is lighter than air, a release will rise to the ceiling of the maintenance facility and quickly dissipate rather than remaining at or near floor level like liquid fuel vapors. Although some of the means of protection for CNG vehicle maintenance facilities are similar to those used for liquid-fueled vehicles (ventilation and elimination of ignition sources), the types and placement of the protection equipment are different because of the behavior of the different fuels. The nature of gaseous methane may also require additional safeguards, such as combustible gas detectors and control systems, or specialized space heating, which are not needed in facilities servicing liquid-fuel vehicles. This handbook covers maintenance facilities that service CNG-fueled vehicles. Although similar requirements are mandated for liquefied natural gas (LNG) or liquefied petroleum gas (LPG) fueled vehicles, LNG and LPG are not covered in this handbook.
Under certain environmental conditions, polyvinyl toluene (PVT) plastic scintillator has been observed to undergo internal fogging. This document reports on a study of acoustic techniques to determine whether they can provide a diagnostic for the fogging of PVT. Different ultrasound techniques were employed for detecting the level of internal fogging in PVT, including wave velocity measurements, attenuation, nonlinear acoustics, and acoustic microscopy. The results indicate that there are linear relations between the wave velocity and wave attenuation with the level of internal fogging. The effects of fogging on ultrasound wave attenuation is further verified by acoustic microscopy imaging, where regions with fog in the specimen demonstration higher levels of attenuation compared to clear regions. Results from the nonlinear ultrasound measurements were inconclusive due to high sensitivities to transducer coupling and fixture variabilities.
Techniques were developed to measure properties at sub-grain scales using depleted Uranium Oxide (d-UO2) samples heat-treated to obtain different grain sizes and oxygen stoichiometries, through three main tasks: 1) sample processing and characterization, 2) microscale and conventional testing and 3) modeling. Grain size and crystallography were characterized using Scanning Electron Microscopy (SEM), in conjunction with Electron Backscattering Diffraction (EBSD) and Electron Channeling Contrast Imaging (ECCI). Grains were then carefully selected based on their crystallographic orientations to perform ex-situ micromechanical tests with samples machined via Focused Ion Beam (FIB), with emphasis on micro-cantilever bending. These experiments were performed under controlled atmospheres, to insure stoichiometry control, at temperatures up to 700 °C and allowed measurements involving elastic (effective Young’s modulus), plastic (critical resolved shear stresses) and creep (creep strain rates) behavior. Conventional compression experiments were performed simultaneously to compare with the ex-situ measurements and study potential size effects. Modeling was implemented using anisotropic elasticity and inelastic constitutive relations for plasticity and creep based on kinematics and kinetics of dislocation glide that account for the effects of crystal orientation, and stress. The models will be calibrated and validated using the experimental data. This project provided insight on correlations among stoichiometry, crystallography and mechanical behavior in advanced oxide fuels, provided valuable experimental data to validate and calibrate mesoscale fuel performance codes and also a framework to measure sub-grain scale mechanical properties that should be suitable for use with irradiated samples due to small volumes required. The goals and metrics of the ongoing study of thermo-mechanical behavior in depleted uranium dioxide (d-UO 2 ) outlined in this project have been concluded successfully, resulting in: 1) the successful fabrication, processing, and characterization of large-grained samples with various orientations (up to and including single crystals) having stoichiometric and hyper-stoichiometric O/U ratios; 2) formulation, calibration, and validation of a crystal plasticity constitutive model to describe the creep deformation of UO 2 at the sub-grain length scale (single crystal level) at intermediate temperatures; 3) the successful calibration of a crystal plasticity constitutive model to describe the elasto-plastic deformation of microcantilever beams, also at moderate temperatures. Samples were prepared from natural uranium oxide powder of production-quality provided by Areva. The powder was pressed in a die to a pressure of 100 MPa to produce green pellets with no sintering aids, lubricants, or any other additives. The green pellets were then heated up to 1700 °C under ultra-high purity argon atmosphere (~1 ppm O2). The atmosphere was then changed to 79% Argon, 21% O 2 and the temperature was held at 1700 °C for 2 hours to sinter the pellets under oxidative conditions [1] that are known to increase grain growth kinetics in UO 2 [2]. Samples were then cooled down under Ar-4%H2 atmosphere to reduce the samples back to stoichiometric UO 2 . For macro-scale procedures, testing of UO 2 samples with large grains was performed at 1200 °C using a modified load frame capable of applying dead-weight loads to ensure constant stress conditions, while displacement of the sample produced by the applied load was measured with high precision micrometers to obtain strains. Stress steps were used during testing and the strains were monitored to measured creep strain rates under steady state for each level of stress used, so that stress exponents could be obtained. The results of the mechanical testing, along with sample geometry and crystal orientation of the grains in the samples, as well as post-test sample characterization were used to formulate a viscoplastic model to account for steady state (stage II) creep behavior, along with basic assumptions from crystal plasticity and kinematic constraints due to testing fixtures. In the micro-scale, testing of microcantilever beams at temperatures ranging from 25 to 570 °C was performed in-situ with a scanning electron microscope with a special attachment to apply load and measure displacement while the samples were at temperature. The load-displacement curves obtained showed linear behavior before fracture for all temperatures attempted except 570 °C, where clear deviations from non-linearity were observed before fracture. These deviations were consistently observed for all samples tested for a given orientation. A viscoplastic model was used to account for the presence of inelastic strain, along with basic assumptions from crystal plasticity and beam theory. These models were kept as simple as possible, and results from tests performed in a set of samples with a given crystal orientation were used to calibrate the material constants for the model, while results from a different sample set were then used for validation, thus satisfying the conditions of all main tasks within the parameters of this project. Details of these efforts are outlined in this report.
Cree successfully executed an 18-month Product Development research program which yielded significant advancements in solid-state luminaire efficacy, optics design, color tunability, and light utilization. The synergistic development of these technologies was intended to result in ultra-high efficacy luminaires with superior beam definition over conventional fixtures, leading to higher spatial light utilization based on application needs. In addition, program-derived technologies are expected to directly benefit automated dimming which reduces time-averaged lighting energy consumption. Program innovations were made in the areas of: light engines; low-profile modular optical designs; ultra-compact color sensors; and low-cost scene sensors for accurate occupancy detection in challenging application settings. Cree’s DOE-supported work in these technology focus areas will set the stage for further development toward productization at Cree.
This set of benchmark subcritical multiplicity experiments was conducted at the ISSA experiment center of Lawrence Livermore National Laboratory. The purpose of these subcritical experiments, as described in the ISSA final design report, was to measure fission neutrons by collecting time-tagged data corresponding to a maximum multiplication of approximately 20. The fission source for this experiment was Materials Test Reactor (MTR)-type highly enriched uranium fuel assembly, which is composed of nineteen fuel plates. One, two, four, six and nine ISSA fuel assemblies were closely packed and loaded inside a support fixture assembly and immersed in water. Four 3 He proportional counters were placed around the fuel assemblies, and list-mode experimental data was taken. Additionally, efficiency calibration measurements with calibrated neutron sources were conducted. The LLNL developed codes BIGFIT and OSANTI RESTART will be used to evaluate the measured data and calculate the experimental multiplication.
Oak Ridge National Laboratory’s (ORNL) Manufacturing Demonstration Facility (MDF) worked with Diversified Tooling Group (DTG) in phase I of this technical collaboration to determine the feasibility of using additive manufacturing to produce automotive tooling using polymer Big Area Additive Manufacturing (BAAM) systems and will potentially work with DTG in phase II on metal BAAM systems. The following phase I goals in polymer BAAM were met: a polymer sheet metal check fixture and a polymer foundry casting pattern were completed and shipped to DTG.
The Main Injector ILA Lambertson magnet uses an 18 inch tapered flange from EVAC. The flange resembles the flange on drawing MD-331910, Flange Weldment MIR Lambertson. Please note that these flanges are heavy. A PALD, portable automotive lifting device, i.e engine hoist, is required as well as the associated lifting fixture, to install the mating flange. The following are the steps to install the EVAC seal drawing MA331512, T/S Conventional Magnet MIR Lambertson Magnet Aluminum Knife Edge Seal.
With current lithium ion batteries optimized for performance under relatively low charge rate conditions, implementation of XFC has been hindered by drawbacks including Li plating, kinetic polarization, and heat dissipation. This project will utilize model-informed design of 3-D hierarchical electrodes to tune key XFC related variables like 1) bulk porosity/tortuosity 2) vertical pore diameter, spacing, and lattice 3) crystallographic orientation of graphite particles relative to exposed surfaces 4) interfacial chemistry of the graphite surfaces through "artificial sEr formation using ALD 5) current collector surface roughness (aspect ratio, roughness factor, etc.). A key aspect of implementing novel electrodes is characterizing them in relevant settings. For this project, ultimately led out of University of Michigan by Neil Dasgupta, that includes both coin cell and 2+ Ah pouch cell testing, as well as comparison testing against baselines. Sandia National Labs will be conducting detailed cell characterization on iterative versions/improvements of the model-based hierarchical electrodes, as well as COTS cells for baseline comparisons. Key metrics include performance under fast charge conditions, as well as the absence or degree of lithium plating. Sandia will use their unique high precision cycling and rapid EIS capabilities to accurately characterize performance and any lithium plating during 6C charging and beyond, coupling electrochemical observations with cell teardown. Sandia will also design custom fixturing to cool cells during rapid charge, to decouple any kinetic effects brought about by cell heating and allow comparisons between different cells and charge rates. Using these techniques, Sandia will assess HOH electrodes from the University of Michigan, as well as aiding in iterative model and electrode design.
The testing of block shear joints to determine ultimate shear strength and modulus is described by the ASTM D905 standard. However, ASTM D905 is not directly applicable for High Explosive (HE) joints, as it requires large masses of HE and the mechanical testing fixture may damage the HE. We have developed capabilities at LLNL to measure the shear strength of adhesive-bonded HE joints.
Performance of accident-tolerant fuel candidates must be assessed during the pellet-cladding mechanical interaction (PCMI) phase of a design-basis reactivity-initiated accident (RIA). Therefore, in this report, we describe Fiscal Year (FY) 2019 research activities on the development of separate-effects testing for ATF cladding candidate iron-chromium-aluminum (FeCrAl) tube specimens under loading conditions comparable to the PCMI. The first section of this report provides modified-burst test (MBT) results of unirradiated FeCrAl tubes at various pressurization-rates and an RIA-relevant temperature (275°C). The failure strain of FeCrAl was observed and calculated using a high-speed digital-image correlation (DIC) technique developed recently under the Department of Energy (DOE)’s Advanced Fuel Campaign (AFC). To overcome the complexities of performing MBT in a hot-cell environment on irradiated samples, a “plane-strain tension” (PST) test was proposed as an alternative methodology for PCMI testing. The relevance of the PST test as an alternative to MBT for irradiated specimens was explicated using the data available in the literature. The design of hot-cell compatible PST fixtures and a specific holder for PST hot-cell specimen machining were developed.
The Pascua Yaqui Tribe has the goal of reducing energy use and costs in its government facilities and housing. In a proactive effort to meet the Tribe's needs an energy audit was performed to accomplish the following goals: Develop an energy efficiency implementation strategy. Prepare an energy audit to identify cost-effective energy efficiency opportunities. Plan and conduct a level II energy audit in tribal government buildings and tribal housing. The audit encompassed four tribal government buildings and a group of residential structures. The purpose of this project was to assess the various facilities energy use in order to inform a means to lower annual consumption. An evaluation of each facility's historical energy and major energy-consuming equipment was performed, and energy conservation measures (ECM's) were identified. An average of 4 ECM's where recommended for each facility. If each facility's recommended ECM's are implemented, the average calculated yearly benefits to the government and residential buildings would result in a 48.3% reduction in electrical energy/costs savings and a 14.4% reduction in natural gas energy/costs savings. Recommended projects for implementation include: Interior Lighting Upgrade, Exterior Lighting Upgrade, Solar Pool Covers, Retro-Commissioning, Low Volt Fixtures, Plug Load Management System, Occupancy Sensor Control, and Solar PV for government/casino buildings and appliance, window, HVAC, Weather Stripping, and water heaters replacement in residences.
Drivers used to operate light-emitting diode (LED) loads form an integral part of the solid-state lighting (SSL) system. While understanding of LED failure modes such as luminous flux depreciation and chromaticity shifts has increased greatly over the past five years, there is still much uncertainty about general failure modes in SSL drivers due to the almost infinite variety of driver typologies. This report, which is the third in a series of three reports on driver robustness, summarizes overall findings from up to 7,500 hours of accelerated stress testing (AST) on two-stage SSL drivers that could be used to operate troffers and similar fixtures. The earlier reports in this series provided initial AST results for both single-channel and multichannel drivers and an interim update on the performance of multichannel drivers in AST.
This project supports the goals of the Energy Policy for the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) through the implementation of an energy efficiency measure (LED lighting retrofit) and construction of a fixed rack (stationary) ground-mounted solar photovoltaic (PV) array energy generation system. The project objective was to eliminate the net demand for grid-based utility energy at two tribal facilities: the CTUIR Field Station and the Public Transit Center (consisting of bus barn and maintenance shop buildings). A total of 332 lighting fixtures were retrofitted with high efficiency LEDs at the three buildings within the project scope. The solar PV array constructed adjacent to the Field Station (46330 Timine Way, Pendleton, OR 97801) has a nameplate capacity of 97.98 kW DC . The project was managed by staff from the CTUIR Energy & Environmental Sciences Program within the Department of Natural Resources and the final budget was $\$ $288,206. Data was collected during a 12 month monitoring period following construction of the aptly named Ántukš–Tín̓qapapt Solar PV Array and assessed to determine project results. During this time, the solar PV system generated 125,580 kWh of energy according to SolrenView solar PV system monitoring service. In contrast, the total realized utility energy and cost savings due to the project were estimated by comparing 24 months of consecutive utility billing data. Results of this comparison indicate that grid-based utility energy demand was reduced by 121,280 kWh, or roughly 80% of the total electricity consumed by both facilities. The cost savings associated with this energy demand reduction were $\$ $11,104 and a payback period of 5.7 years was estimated for recovering the CTUIR’s investment. However, it should be noted that these figures are not representative of the savings that could be obtained under normal, error-free (i.e. faultless) conditions. Several undesirable events occurred during the 12 month monitoring and evaluation period, the effects of which were quantified using available data so that results under a “Faultless Scenario” could be estimated. Annual energy and cost savings estimated for the Faultless Scenario were approximately 166,289 kWh and $\$ $15,225, respectively. These figures should prove to be more representative of the long-term average annual results achieved in response to the project and suggest a payback period closer to 4.5 years for the CTUIR.
In this program we demonstrated three cost-effective and practical means for extracting light from an organic light emitting diode (OLED) based lighting fixture. Conventional OLEDs emit only 20% of the light produced in their active regions due to light trapping and losses of the light incident on metal contacts. Our methods for light extraction, that eliminate both of these substantial losses, include placement of a grid-mirror at the substrate side of top-emitting OLEDs, using an ultralow cost diffusing surface at the substrate side of top-emitting OLEDs, and employing high index of refraction sub-electrode microlens arrays (SEMLA). All of these methods result in light emission that is wavelength and viewing angle independent, does not interfere with the OLED structure itself, and is of potentially low cost. By combining the SEMLA solution with substrate outcoupling such as microlens arrays or index matching fluid, up to 70% of the light can be extracted from the OLEDs, thus meeting all of the program objectives. Furthermore, the solutions have been transferred to the industrial sector where efforts at commercialization are underway with the continued involvement of the inventors.
With current lithium ion batteries optimized for performance under relatively low charge rate conditions, implementation of XFC has been hindered by drawbacks including Li plating, kinetic polarization, and heat dissipation. This project will utilize model-informed design of 3-D hierarchical electrodes to tune key XFCrelated variables like 1) bulk porosity/tortuosity 2) vertical pore diameter, spacing, and lattice 3) crystallographic orientation of graphite particles relative to exposed surfaces 4) interfacial chemistry of the graphite surfaces through "artificial sEr' formation using ALD 5) current collector surface roughness (aspect ratio, roughness factor, etc.). A key aspect of implementing novel electrodes is characterizing them in relevant settings. For this project, ultimately led out of University of Michigan by Neil Dasgupta, that includes both coin cell and 2+ Ah pouch cell testing, as well as comparison testing against baselines. Sandia National Labs will be conducting detailed cell characterization on iterative versions/improvements of the model-based hierarchical electrodes, as well as COTS cells for baseline comparisons. Key metrics include performance under fast charge conditions, as well as the absence or degree of lithium plating. Sandia will use their unique high precision cycling and rapid EIS capabilities to accurately characterize performance and any lithium plating during 6C charging and beyond, coupling electrochemical observations with cell teardown. Sandia will also design custom fixturing to cool cells during rapid charge, to decouple any kinetic effects brought about by cell heating and allow comparisons between different cells and charge rates. Using these techniques, Sandia will assess HOH electrodes from the University of Michigan, as well as aiding in iterative model and electrode design.
Understanding the interfacial behavior of two materials sliding relative to each other is import ant in computational modeling and simulating impact or shock response of components, subsystems, and even full-scale systems. Although often considered as a constant for different applications, the coefficient of friction may be dependent on a number of factors such as normal force, roughness, material type, temperature, and sliding velocity. In this study, a new method based on a Kolsky tension bar with a custom-made friction fixture was developed for measurement of the dynamic friction coefficient between two metallic materials at high sliding velocities. In this new method, polyvinylidene fluoride (PVDF) thin film force sensors were used to measure the normal force, while a strain gage on the transmission bar was used to measure the friction force. As such, the dynamic friction coefficient is calculated with the normal and friction forces. The impact velocity can be varied to investigate the dependency of friction coefficient on impact velocity. To evaluate the technique, friction coefficients between 4340 steel and 7075-T6 we re measured at three different sliding velocities of 4, 8 and 11 m/s. Effects of surface roughness, normal force, and impact speed were also explored . Decreased static and kinetic friction coefficient s were observed when the normal force was increased at constant sliding velocity. With increasing velocity, the friction coefficient remained fairly constant for the three velocities studied. Higher friction coefficients were measured when the specimen roughness was increased.