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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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This data set contains openly-documented, machine readable digital research data corresponding to figures published in K.E. Thome et al., 'High Confinement Mode and Edge Localized Mode Characteristics in a Near-Unity Aspect Ratio Tokamak,' Phys. Rev. Lett. 116, 175001 (2016).
This data set contains openly-documented, machine readable digital research data corresponding to figures published in K.E. Thome et al., 'H-mode Plasmas at Very Low Aspect Ratio on the Pegasus Toroidal Experiment,' Nucl. Fusion 57, 022018 (2017).
This public data set contains openly-documented, machine readable digital research data published in M.W. Bongard, et al., 'On Virial Analysis at Low Aspect Ratio,' Phys. Plasmas 23, 072508 (2016).
This public data set contains openly-documented, machine readable digital research data corresponding to figures published in M.G. Burke et. al., 'Continuous, Edge Localized Ion Heating During Non-Solenoidal Plasma Startup and Sustainment in a Low Aspect Ratio Tokamak,' Nucl. Fusion 57, 076010 (2017).
A total of 35 Superconducting SSR2 spoke cavities will be installed in the PIP II SRF linac at Fermilab and a total of 8 prototype SSR2 cavities will be manufactured for the prototype cryomodule. In this paper, the mechanical design and fabrication aspects of the prototype jacketed SSR2 cavity will be presented. RF and mechanical design activities were conducted in parallel directly on the jacketed cavity in order to minimize the number of design iterations. Also, the lessons learned from other spoke cavities experiences (i.e. SSR1 at Fermilab and ESS double spoke at IPNO) were considered since the early stage of the design.
Climate change [i.e., high atmospheric carbon dioxide (CO 2 ) concentrations (≥400 ppm); increasing air temperatures (2-4°C or greater); significant and/or abrupt changes in daily, seasonal, and inter-annual temperature; changes in the wet/dry cycles; intensive rainfall and/or heavy storms; extended periods of drought; extreme frost; heat waves and increased fire frequency] is and will significantly affect soil properties and fertility, water resources, food quantity and quality, and environmental quality. Biotic processes that consume atmospheric CO 2 and create organic carbon (C) that is either reprocessed to CO 2 or stored in soils, are the subject of active current investigations with great concern over the influence of climate change. In addition, abiotic C cycling and its influence on the inorganic C pool in soils is a fundamental global process in which acidic atmospheric CO 2 participates in the weathering of carbonate and silicate minerals, ultimately delivering bicarbonate and Ca 2 + or other cations that precipitate in the form of carbonates in soils or are transported to the rivers, lakes, and oceans. Soil responses to climate change will be complex, and there are many uncertainties and unresolved issues. The objective of the review is to initiate and further stimulate a discussion about some important and challenging aspects of climate-change effects on soils, such as accelerated weathering of soil minerals and resulting C and elemental fluxes in and out of soils, soil/geo-engineering methods used to increase C sequestration in soils, soil organic matter (SOM) protection, transformation and mineralization, and SOM temperature sensitivity. This review reports recent discoveries and identifies key research needs required to understand the effects of climate change on soils.
Life extension of the existing nuclear reactors imposes accumulated damages, such as higher fluences and longer period of corrosion, to structural materials, which would result in significant challenges to the traditional reactor materials such as type 304 and 316 stainless steels. Advanced alloys with superior radiation resistance will increase safety margins, design flexibility, and economics for not only the life extension of the existing fleet but also new builds with advanced reactor designs. The Electric Power Research Institute (EPRI) teamed up with Department of Energy (DOE) to initiate the Advanced Radiation Resistant Materials (ARRM) program, aiming to develop and test degradation resistant alloys from current commercial alloy specifications by 2021 to a new advanced alloy with superior degradation resistance in light water reactor (LWR)-relevant environments by 2024. Corrosion resistance in water environment is one of the fundamental properties required for LWR core internal materials. High-temperature steam oxidation tests are not only an accelerated life testing method to uncover potential failure modes in a short period of time, but also an approach to evaluate materials’ resistance to accidental scenarios. Coupons, prepared from fourteen candidate alloys that were selected under the ARRM program, were exposed to 1 bar full steam with ~10 part-per-billion oxygen content at 600 and 650°C for up to 5,000 h, which were weighed at 500-h intervals. Ni-base superalloys are an important class of alloys for reactor applications. Alloys 690, 725, and X- 750 were three of the selected Ni-base superalloys exposed to the steam tests. This report summarizes the metallurgical aspects, such as alloy thermodynamics and the nature of the oxides and the diffusivities of primary elements, and their effects on oxidation behavior of the three alloys. In addition to monitoring mass change, microstructures of the 5000h-exposed samples of alloys 690, 725, and X-750 were characterized using scanning and transmission electron microscopy and energy dispersive x-ray spectroscopy. Together with thermodynamic calculations, the scale constitution and its exfoliation behavior were discussed. Based on experimental and theoretical values, a new model was proposed to quantitatively estimate the metal thickness loss of the alloys. Alloy X-750 was found to have the best resistance to steam oxidation with the least metal thickness loss (<1 μm), which were slightly superior to alloy 690. Alloy 725 exhibited the worst resistance to steam oxidation with the greatest metal thickness loss, e.g., ~2.5 μm at 650°C, which is nearly three times of the metal thickness losses of alloys 690 and X-750 at 650°C. The greatest metal thickness loss of alloy 725 might be attributable to its high Mo content. Photos of the fracture toughness tested samples of eight alloys are presented, which will be correlated with their fracture toughness results and planned tensile test results to select representative alloy samples for detailed microstructural characterization to reveal their microstructure and properties relationships.
4th quarter presentation for FY20 SDRD Annual Meeting to be held Sept. 23-24 on WebEx. Advanced Characterization of Spatial Aspects of Image System Blur, NLV-004-19, Year 2
When modeling thin structures, some analysts use shell elements. Others choose hex elements. Both element types have their advantages and disadvantages. This memo describes a weakness of using hex elements to model bending. Specifically, the accuracy degrades as the element aspect ratio increases. This study illustrates this effect for the mean quadrature and the selective deviatoric formulations. For the test case considered, the selective deviatoric formulation produces larger errors.
Plasma etching of semiconductors is an essential process in the production of microchips which enable nearly every aspect of modern life. Two frequencies of applied voltage are often used to provide control of both the ion fluxes and energy distribution.
Consumer demand for electricity has often been thought of as homogenous and inelastic. However, consumers may have preferences for their electricity consumption that they have been unable to realize due to the structures of electricity rates, and historic methods of regulation. As ratemaking becomes more dynamic, consumers will have a newfound ability to realize these preferences. This paper conducts a review of this issue through the lenses of utility regulation, neoclassical economics, and behavioral economics. It surveys what aspects of consumer preferences and behavior have been well established for the electricity sector and identifies gaps that could be filled by future research. This analysis has implications for stakeholders looking to understand how households will function in transactive and real time pricing environments.
I give an overview of (mostly my own) work on aspects of QCD dynamics in hadronic form factors at large momentum transfer. The topics include a discussion of basics of soft and hard mechanisms, QCD sum rule applications, and connection of form factors to generalized parton distributions.
Presentation for a seminar at Keio University on aspects of large- N f quantum field theories.
The goal of this work is to develop a wafer level copper electrochemical deposition process for high aspect ratio through silicon vias and test the reliability and functionality of TSVs for integration into MEMS applications.
Integrated PV technologies - such as agrivoltaics - have potential to address challenges associated with siting and land use for solar. This presentation provides an overview of agrivoltaic R&D activities in the United States and focuses on the non-technical aspects of implementation, specifically social considerations around collaboration, planning, and acceptance.
Presentation on computational aspects of National Transmission Planning Study supporting a panel discussion.
The presentation will provide an overview of automotive power electronics and electric machines thermal management systems that are typical for light-duty vehicles. Unique thermal and environmental aspects related to medium and heavy-duty vehicle applications will then be discussed. Finally, advanced thermal management and packaging technologies that could be evaluated and used in this project will be described.
: The present review describes the methodological aspects and prospects of the productionof Positron Emission Tomography (PET) radiometals in a liquid target using low-medium energymedical cyclotrons. The main objective of this review is to delineate and discuss the critical factorsinvolved in the liquid target production of radiometals, including type of salt solution, solutioncomposition, beam energy, beam current, the effect of irradiation duration (length of irradiation)and challenges posed by in-target chemistry in relation with irradiation parameters. We also summarizethe optimal parameters for the production of various radiometals in liquid targets. : Additionally, we discuss the future prospects of PET radiometals production in the liquid targetsfor academic research and clinical applications. Significant emphasis has been given to the productionof 68 Ga using liquid targets due to the growing demand for 68 Ga labeled PSMA vectors, [ 68 Ga]-Ga-DOTATATE, [ 68 Ga]Ga-DOTANOC and some upcoming 68 Ga labeled radiopharmaceuticals.Other PET radiometals included in the discussion are 86 Y, 63 Zn and 89 Zr.