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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 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Fundamental Corrosion Studies in High-Temperature Molten Salt Systems for Next Generation Concentrated Solar Power Systems

The objective of this project is to increase Concentrated Solar Power (CSP) system lifetime through characterization of corrosion mechanisms in heat transfer systems and identification of materials and corrosion resistance methods applicable at temperatures above 850°C. Coupling of experimental methods with thermodynamic and kinetic modeling has given greater insight into the corrosion phenomena and enabled modeling of the corrosion in molten chloride heat transfer systems. The project has been identified the selective oxidation of Cr along the grain boundaries of high Cr content alloys as the principle corrosion mechanisms occurring in CSP systems. The corrosion rate was also found to be mass transfer limited by diffusion of chromium chlorides along the grain boundaries. It was shown that the corrosion could be increased by adding naturally convective flow to mechanism using a thermosiphon. A reaction mechanism has been proposed for selective oxidation of Cr that is driven by the electrochemical potential difference between the Ni crucible for immersion testing and the alloy coupon. This driving force will be similar to the differences caused by having varying Ni content or Cr content throughout a heat transfer system. It could also mimic the differences in electrochemical potential between various parts of the system that are at different temperatures. The reaction mechanism consists of an initiation step due to system impurities and a set of propagation steps that results in formation of a NiCr alloy at the crucible that drives corrosion and selective oxidation of Cr from the alloy. The presences of chromium chlorides in the salt are also essential to the corrosion mechanism to transport the Cr. The formation of a NiCr alloy on the crucible surface with no contact between the alloy coupons and the crucible provides support to this mechanism of having corrosion reactions occurring at both the alloy and the crucible. The thermodynamics of this reaction mechanism have been modeled and were shown to be galvanic. A corrosion model has been developed based on this mechanism and has been implemented in CFD so that it can be used to predict corrosion in a wide variety of system geometries. The model was validated using the thermosiphon data and dimensionless analysis. The corrosion rates of the samples were modeled to within 10% percent of the experimental values. The model has been extended to include the effect of Mg corrosion inhibitor on the corrosion rate in the system. The use of Mg as a metallic corrosion inhibitor has been demonstrated as a method to reduce the corrosion rate of alloys in molten chlorides to below 15 microns per year. Mg is an effective corrosion inhibitor at concentrations as low as 0.3 mol%. Corrosion potential monitoring experiments have shown that the Mg lowers the corrosion potential for the alloy below the equilibrium potential for Cr oxidation and thus prevents corrosion. Experiments have been performed on the ability of Mg to inhibit corrosion in realistic environments that include lower purity salts and welded and stressed alloys. The results have shown that for all these scenarios the corrosion can be reduced to meet the DOE targets. The electrochemical monitoring of Mg for process control has also been demonstrated.

14 SOLAR ENERGY↗
DOE OSTI2014

Leveraging a Fundamental Understanding of Fracture Flow, Dynamic Permeability Enhancement, and Induced Seismicity to Improve Geothermal Energy Production

This project focused on assessment and discovery of fluid-rock interaction in geothermal reservoirs. We accomplished work in four main areas: 1) fracture formation and the relationship between fluid flow and shear failure, 2) assessment of fracture geometry and fluid permeability using novel acoustic measurements, 3) an improved understanding of how drilling, injection and geothermal production influence local seismicity, and 4) development of process based models for using induced seismicity to assess the critical stress-state in Earth’s crust. The majority of the work involved laboratory experiments and analysis of laboratory and numerical results. We created shear fractures under true triaxial stresses designed to mimic the stress state of a geothermal reservoir and we measured fracture permeability as a function of stress state and fluid pressure under these conditions. Our work shows that fracture permeability can be altered by transient changes in stress and fluid flow. We find that fluid pressure has an unexpectedly larger impact on permeability than does applied stress and we interpret that result in terms of fracture contact area and the law of effective stress. We employ elastic waves to image fractures in the lab and develop the theory to apply our work to geothermal reservoir scale. Our work documents changes in elastic wave speed prior to earthquake-like failure in the lab and we show how the frequency magnitude distribution of microseismic lab earthquakes can be used to assess the critical stress state around faults prior to failure.

15 GEOTHERMAL ENERGY↗
DOE OSTI2019

Cosmological Probes of Fundamental Physics (Final Report)

This report summarizes the research performed by Hirata’s group under award # DE-SC0006624, which contains both theoretical and observational parts. The theoretical part includes studies of the physics of the reionization era, the period in cosmic history when the first stars and galaxies emitted ultraviolet radiation and turned the intergalactic medium from neutral to ionized. We investigated the ways in which future observations of this era using the 21 cm line of hydrogen could probe inflation (through the effects of gravitational waves on the statistics of this line) and primordial magnetic fields. We also investigated how the physics of the reionization era could impact measurements of the Lyman-α forest using current (BOSS/eBOSS) and near-future (DESI) instruments. It also included a detailed study of sterile neutrinos as a dark matter candidate, including the early Universe modeling required to predict the distribution of sterile neutrinos on small scales. The observational arm of the project included preparations for ground- and space-based dark energy surveys (including PFS and WFIRST), as well as measurements of the growth of structure from the Sloan Digital Sky Survey.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Neutrinoless Double-Beta Decay Searches and Other Fundamental Physics Measurements with Ultra-Low Background Enriched-Germanium Detector Arrays

This award funded research on the MAJORANA DEMONSTRATOR neutrinoless double-beta decay search. The project encompassed three major goals and objectives. The first was construction and commissioning of the MAJORANA DEMONSTRATOR. My group members played a significant role in the project’s successful construction and commissioning. The second major objective was the MAJORANA DEMONSTRATOR data analysis and related activities, in which my group played a leading role in the collaboration. In addition to coordinating the entire analysis, my group was responsible for the development of several of the primary analysis parameters, as well as many lower-level components. This effort brought to fruition a number of important publications, including the release of the MAJORANA DEMONSTRATOR’s first limits on neutrinoless double beta decay and its measurements of its background levels. The third goal was to perform auxiliary background studies and future detector R&D with a local HPGe detector test stand. The test stand was constructed and operated, and is ready to be used for subsequent R&D under the purview of the MAJORANA DEMONSTRATOR’s follow-on experiment, LEGEND.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2019

Performance Assurance Planning: Continuous Design-Level Performance of Each Energy Conservation Measure in a Utility Energy Service Contract is Fundamental to Achieving Projected Results

An energy savings performance contract energy sales agreement (ESPC ESA) is a project structure, similar to a power purchase agreement, that uses the multiyear ESPC authority to implement renewable energy projects (referred to as ESA energy conservation measures [ECMs]) on federal buildings or land. The ESA ECM is initially privately owned for tax-incentive purposes, and the federal agency purchases the electricity it produces. An ESPC ESA is one of the most cost-effective methods for implementing on-site distributed energy projects at civilian federal agency sites.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Fundamental Properties of Confined Enzymes

We recently developed an enzymatically active, ultra-thin, nano-stabilized liquid membrane for CO 2 separation from a mixture of gases, which was recognized by an international R&D 100 Award in 2015. The separation membrane is an approximately 18-nm thick water layer stabilized by capillary condensation within a hydrophilic mesoporous silica film and embedded with the metallo-enzyme carbonic anhydrase. The enzyme speeds CO 2 uptake and release from the membrane by catalyzing the rapid inter-conversion of carbon dioxide and water to bicarbonate and a proton. The membrane separates CO 2 from 1:1 gas mixtures at a rate of 2600 GPU with CO 2 /N 2 and CO 2 /H 2 selectivities exceeding 788 and 1500, the highest combined flux and selectivity yet reported. That membrane performance exceeds, for the first time, the U.S. Department of Energy standards for CO 2 capture technology. CO 2 flux depends sensitively on nanopore surface chemistry in the active region. To understand that dependence, we applied molecular simulations to interrogate enzyme behavior in the presence of varied surface chemistries. The results indicate that a polar surface chemistry within the membrane nanopores prevents aggregation of enzymes that would otherwise occur in both bulk liquid solution and non-polar nanopores. Additionally, the enzyme active site maintains a stable structure, even when the overall protein structure deforms within the nanopores. In summary, confinement in the ultra-thin layer of water within mesoporous silica nanopores facilitates a 15x higher enzyme concentration than in bulk conditions, without affecting the structure of the enzyme active site, when the nanopore surfaces are covered with polar functional groups. Thus, confinement of the carbonic enzymes in the membrane water-filled nanopores facilitates higher rates of CO 2 uptake and release than achievable in bulk solutions.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Advancement of Supercritical Carbon Dioxide Technology through Round Robin Testing and Fundamental Modeling

Growing interest in supercritical carbon dioxide (sCO 2 ) cycles for advanced reactors is driving the need for corrosion data on candidate plant materials. The sCO 2 Brayton cycle is being considered for power conversion systems for a number of nuclear reactor concepts including the sodium fast reactor, fluoride salt-cooled high temperature reactor, high temperature gas reactor, and several types of small modular reactors. Multiple organizations have developed test facilities to address the corrosion data knowledge gap in high temperature, high pressure sCO 2 environments but, to date, there has been no formal test program among these organizations to validate the consistency of the data they produce. A demonstration of comparable and reproducible results enables a coordinated effort to explore the sCO 2 parameter space relevant to advanced reactor technology. This proposal establishes a round robin test plan for sCO 2 corrosion testing and the organization of a sCO 2 Materials Group to guide future materials testing directions. Furthermore, this proposal outlines efforts to elucidate the mechanisms of sCO 2 corrosion by performing identical tests in supercritical steam, testing model alloys with various composition and environmental conditions, accompanied by modeling efforts to study rate controlling mechanisms of corrosion and to help understanding the effects of impurities.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Fundamental Forces, Lasting Impressions: Historical Documentation of the Sigma Press Building (TA-3-35) Volume 1

The US Department of Energy, National Nuclear Security Administration, Los Alamos Field Office (Field Office) has prepared final documentation for the resolution of adverse effects to Building 35 in Technical Area (TA) 3 at Los Alamos National Laboratory (LANL or the Laboratory). This documentation is being submitted to the New Mexico State Historic Preservation Officer (SHPO). TA-3-35, a Cold War-era press building, was determined eligible for listing in the National Register of Historic Places (Register) in the report Pressing Matters: An Evaluation of the Cold War Buildings at the Sigma Complex (LA-UR-15-28961). This report also identified Building TA-3-35 as excess property to be decontaminated, decommissioned, and demolished by the LANL Footprint Reduction Program in Fiscal Year 2016, an adverse effect requiring mitigation. The SHPO concurred with the both the eligibility determination of, and adverse impact to, Building TA-3-35 on February 29, 2016.

42 ENGINEERING↗
DOE OSTI2019

Build and test a novel low heat leak fundamental power coupler

Fermi National Accelerator Laboratory and Euclid Techlabs propose to build and test prototypes of a new RF power coupler. The prototype solves reliability problems associated with present power couplers, which may lead to increased up-time of national laboratory accelerators for scientific users, as well as encourage development of industrial, medical, and security accelerator applications. The goal of the proposed project is to build and test a prototype of a proprietary coupler developed by Fermilab. The prototype will permit evaluation of reliability and low cryogenic heat leak in subsequent testing under a follow-on to this pilot program. The prototype design will be fabricated at Euclid Techlabs and tested at Fermilab using existing 1.3 GHz RF infrastructure.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Fundamental Science of Doping and Defects in Ga 2 O 3 for Next Generation Power Semiconductors

The aim and scope of this project was the development of a capability to prepare high-quality, epitaxial beta gallium oxide films by oxide reactive molecular-beam epitaxy. The purpose was to demonstrate that beta gallium oxide could be grown by such a method using Sandia’s existing oxide molecular-beam epitaxy instrument. The key activity in this project was the installation of a gallium oxide capability on the Sandia instrument. This required the acquisition of several custom items for the instrument, including: a gallium effusion cell, appropriate cell power supplies and temperature controllers, a shutter to block beam flux, installation of an existing ozone generator with a directed gas nozzle and controlled leak valve, and re-routing the chilled water system to accommodate the cell. In addition, beta gallium oxide single crystals were acquired and their surfaces characterized by reflection high energy electron diffraction.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Fundamental Piezotronic and Piezo-phototronic Effects in Nanowires

The piezo-phototronic effect is about the use of the piezoelectric potential created inside some materials for enhancing the charge carrier generation or separation at the metal-semiconductor contact or p-n junction. We demonstrate the impact of the piezo-phototronic effect on the photon sensitivity for a ZnO-CdS core-shell micro/nanowire based visible and UVsensor. CdS nanowire arrays were grown on the surface of a ZnO micro/nanowire to form a ZnO-CdS core-shell nanostructure by a facile hydrothermal method. With the two ends of a ZnO-CdS wire bonded on a polymer substrate, a flexible photodetector was fabricated, which is sensitive simultaneously to both green light (548 nm) and UV light (372 nm). The photocurrent and sensitivity of the ZnO_CdS wire photodetector is 103 times higher than that of CdS nanoribbon, and the responsivity (11 A W -1 , 548 nm, at 2 V bias) is nearly 100 times higher than that of ZnSe-nanobelt-based blue/UV-light sensor (0.12 AW -1 , 400 nm, at 30 V bias). Moreover, the performance of the ZnO-CdS wire photodetector upon illumination of visible and UV light can be both further enhanced for more than 10 times with the participation of the piezo-phototronic effect when the device is subjected to a -0.31% compressive strain. This investigation extends the application of the piezo-phototronic effect in a wide spectrum photon detector.

14 SOLAR ENERGY↗
DOE OSTI2019

Fundamental Understanding of Methane-Carbon Dioxide-Water (CH 4 -CO 2 -H 2 O) Interactions in Shale Nanopores under Reservoir Conditions (Quarterly Report)

Shale is characterized by the predominant presence of nanometer-scale (1-100 nm) pores. The behavior of fluids in those pores directly controls shale gas storage and release in shale matrix and ultimately the wellbore production in unconventional reservoirs. Recently, it has been recognized that a fluid confined in nanopores can behave dramatically differently from the corresponding bulk phase due to nanopore confinement (Wang, 2014). CO 2 and H 2 O, either preexisting or introduced, are two major components that coexist with shale gas (predominately CH 4 ) during hydrofracturing and gas extraction.

58 GEOSCIENCES↗
DOE OSTI2019

Cosmological Probes of Fundamental Physics

The Lyman-alpha forest is a key probe of the expansion history and of structure formation in the Universe at intermediate redshifts (2<z<5). This report describes two investigations into astrophysical systematic errors in the Lyman-alpha forest: reionization imprints (which affect the broadband power spectrum) and streaming velocities (which affect the baryon-acoustic oscillation feature).

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Fundamentals of Nuclear Security Culture [PowerPoint]

We examine the following topics: Nuclear and Radiological Security Culture; Threats and consequences ; The Human Factor; Legal and Regulatory Basis for Security Culture; Security Culture basic concepts; Systematic SC program; Enhancing SC; and, Situational Awareness. We will discuss these aspects and conduct exercises to apply them

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2020

Fundamental problems in astroparticle physics and cosmology (Final Technical Report)

In the standard cosmological model, structure forms when gas cools and condenses to the center of dark matter halos. The onset of structure is governed by rapid star formation and subsequent evolution of the first massive stars. One of the endpoints of stellar evolution is the formation of a black hole. We showed that all black hole merger events must occur after the universe is about 85 million years old. This prediction is important because it means that if a future experiment makes a detection of a black hole merger event at an earlier time then our understanding of cosmology and the onset of structure formation is not fully developed. In addition, we explored dark matter models that have either self-interactions or experience decays. In the first case, self-interactions may lead to the formation of a thick disk that can be co-planar to the Galactic disc due to correlations in angular momentum between dark matter and baryons that are predicted by tidal torque theory. We showed that for heavy dark matter particles, either the self interaction may not be strong enough to solve the small scale structure motivation or a dark disc cannot be present in the Milky Way. In the second-case, we showed that if dark matter experiences decays into two particles, one of which behaves like radiation, then it is possible to relieve the tension that exists between measurements of the local expansion rate. Finally, we developed methods on how to distinguish gamma-ray excesses from promising dark matter targets as compared to conventional astrophysical sources. This is an important toolset that is applicable to any suspected dark matter source.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Fundamental Science and Technology of Flash Processing Robustness for Advanced High Strength Steels (AHSS)

“Flash processed” low carbon steel sheets were characterized using in-situ IR imaging, ex-situ dome deformation testing and microscopy. Due to flash processing set-up, cooling water flow and steam interfered with robust infrared temperature measurements. Though preliminary, rapidly heating the steel sheet to greater than 1170°C and then water quenching a few seconds later can result in through thickness microstructural gradients, where the center is harder than the exterior surfaces. This microstructural configuration sometimes results in a dome displacement ~75% relative to that observed in the more ductile as-received material. The presence of aluminum nitride (AlN) inclusions was confirmed, a likely byproduct from a de-oxidization reaction, and may reduce dome displacement (similar to strain to failure) significantly. Based on thermodynamic calculations, a high flash processing temperature (>1170°C) is recommended to dissolve these AlN inclusions in the austenite phase.

36 MATERIALS SCIENCE↗