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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 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

THE EVOLUTION OF THE DUSTY TORUS COVERING FACTOR IN QUASARS

We have assembled a large sample of 5996 quasars at 2.0 {<=} z {<=} 2.4 (high-z) or 0.7 {<=} z {<=} 1.1 (low-z) from the Sloan Digital Sky Survey (SDSS) ninth and seventh data release and quasar catalogs. The spectral energy distributions of quasars were constructed by collecting WISE, UKIDSS, and GALEX photometric data in addition to SDSS data, from which the IR luminosity at 1-7 {mu}m and bolometric luminosity at 1100 A-1 {mu}m were calculated. A red tail is clearly seen in the distribution of the spectral index over 1100 A-1 {mu}m for both the high-z and low-z sources; this tail is likely due to red or reddened quasars. The covering factor (CF) of the dusty torus is estimated as the ratio of the IR luminosity to the bolometric luminosity. We find significant anti-correlations between the CF and the bolometric luminosity, in both the high-z and low-z quasars; however, these two groups follow different tracks. At overlapping bolometric luminosities, the CF of high-z quasars is systematically larger than those of low-z quasars, implying an evolution of the CF with redshift.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

Characterization of a high-temperature superconducting conductor on round core cables in magnetic fields up to 20 T

The next generation of high-ï¬eld magnets that will operate at magnetic ï¬elds substantially above 20 T, or at temperatures substantially above 4.2 K, requires high-temperature superconductors (HTS). Conductor on round core (CORC) cables, in which RE-Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (RE = rare earth) (REBCO) coated conductors are wound in a helical fashion on a flexible core, are a practical and versatile HTS cable option for low-inductance, high-field magnets. We performed the first tests of CORC magnet cables in liquid helium in magnetic fields of up to 20 T. A record critical current I{sub c} of 5021 A was measured at 4.2 K and 19 T. In a cable with an outer diameter of 7.5 mm, this value corresponds to an engineering current density J{sub e} of 114 A mm{sup -2} , the highest J{sub e} ever reported for a superconducting cable at such high magnetic fields. Additionally, the first magnet wound from an HTS cable was constructed from a 6 m-long CORC cable. The 12-turn, double-layer magnet had an inner diameter of 9 cm and was tested in a magnetic field of 20 T, at which it had an I{sub c} of 1966 A. The cables were quenched repetitively without degradation during the measurements, demonstrating the feasibility of HTS CORC cables for use in high-field magnet applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Cosmic bubble and domain wall instabilities III: the role of oscillons in three-dimensional bubble collisions

We study collisions between pairs of bubbles nucleated in an ambient false vacuum. For the first time, we include the effects of small initial (quantum) fluctuations around the instanton profiles describing the most likely initial bubble profile. Past studies of this problem neglect these fluctuations and work under the assumption that the collisions posess an exact SO(2,1) symmetry. We use three-dimensional lattice simulations to demonstrate that for double-well potentials, small initial perturbations to this symmetry can be amplified as the system evolves. Initially the amplification is well-described by linear perturbation theory around the SO(2,1) background, but the onset of strong nonlinearities amongst the fluctuations quickly leads to a drastic breaking of the original SO(2,1) symmetry and the production of oscillons in the collision region. We explore several single-field models, and we find it is hard to both realize inflation inside of a bubble and produce oscillons in a collision. Finally, we extend our results to a simple two-field model. The additional freedom allowed by the second field allows us to construct viable inflationary models that allow oscillon production in collisions. The breaking of the SO(2,1) symmetry allows for a new class of observational signatures from bubble collisions that do not posess azimuthal symmetry, including the production of gravitational waves which cannot be supported by an SO(2,1) spacetime.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

An Advanced Cooling Device for Concentrated Photovoltaic Systems

Concentrated photovoltaics (CPV) have the potential to significantly enhance the energy conversion utilization of solar panels and reduce solar generation costs, making them a crucial area of advancement in solar power generation technology. However, the concentration of sunlight can lead to overheating of solar panels, resulting in a notable reduction in both the efficiency of solar power generation and the lifespan of the panels. This challenge remains the predominant technical hurdle that hinders the application of concentrated photovoltaic power generation technology. In this study, we propose a new cooling method for concentrated photovoltaic power generation systems via an integrated approach of incorporating Phase-Change Thermal Storage (PCTS) and Thermoelectric Generator (TEG) technology. This new method not only enhances the overall system's electricity generation efficiency but also effectively resolves the technical challenge of concentrated photovoltaic panel overheating issues, ensuring the continuity of concentrated photovoltaic power generation and extending the lifespan of solar panels and their components. In order to make full use of the wasted heat generated by photovoltaic power generation and effectively improve the power generation efficiency of the system, this work developed a phase change heat storage device based on a phase change material. This device uses the temperature difference between day and night to recover wasted heat from photovoltaic power generation. Through integration with the thermoelectric power generation system, thermal energy can be converted into electrical energy. In addition, the Peltier effect of thermoelectric materials is used to construct a photovoltaic panel overheating protection system, which significantly improves the reliability and service life of the system.

14 SOLAR ENERGY↗
DOE OSTI2021

Qualification of 3-D Printed Mortar With Electrical Conductivity Measurements

Additive manufacturing (AM) or 3D printing of concrete allows for construction of arbitrary shape structures without a mold. Since reproducibility of 3D printed concrete is lower than that of conventional fabrication, each 3D printed structure should be monitored for proper curing. Conventional qualification of concrete is based on several tests, including destructive compressive strength measurements. Because a structure is 3-D printed layer-by-layer, the surfaces of AM concrete structures have significant surface roughness. This limits the applicability of conventional nondestructive testing methods. We investigated qualification of 3D printed mortar by monitoring curing with nondestructive electrical conductivity measurements. Bulk resistance of concrete was extracted from electrochemical impedance spectroscopy (EIS measurements made using custom flexible self-adhesive electrodes, which contour to rough surfaces. We show that bulk resistivity of concrete increases linearly with time. This allows for developing a calibration curve for compressive strength lookup from nondestructive electrical conductivity measurements. Conductivity measurements also allow for estimation of formation factor, which is an indicator of mortar permeability.

36 MATERIALS SCIENCE↗
DOE OSTI2021

A multiresolution adaptive wavelet method for nonlinear partial differential equations

We report the multiscale complexity of modern problems in computational science and engineering can prohibit the use of traditional numerical methods in multi-dimensional simulations. Therefore, novel algorithms are required in these situations to solve partial differential equations (PDEs) with features evolving on a wide range of spatial and temporal scales. To meet these challenges, we present a multiresolution wavelet algorithm to solve PDEs with significant data compression and explicit error control. We discretize in space by projecting fields and spatial derivative operators onto wavelet basis functions. We provide error estimates for the wavelet representation of fields and their derivatives. Then, our estimates are used to construct a sparse multiresolution discretization which guarantees the prescribed accuracy. Additionally, we embed a predictor-corrector procedure within the temporal integration to dynamically adapt the computational grid and maintain the accuracy of the solution of the PDE as it evolves. We present examples to highlight the accuracy and adaptivity of our approach.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

How to GAN Higher Jet Resolution

QCD-jets at the LHC are described by simple physics principles. We show how super-resolution generative networks can learn the underlying structures and use them to improve the resolution of jet images. We test this approach on massless QCD-jets and on fat top-jets and find that the network reproduces their main features even without training on pure samples. In addition, we show how a slim network architecture can be constructed once we have control of the full network performance.

Baldi, Pierre↗
DOE OSTI2013

Exposure Evaluation for Benzene, Lead and Noise in Vehicle and Equipment Repair Shops

An exposure assessment was performed at the equipment and vehicle maintenance repair shops operating at the U. S. Department of Energy Hanford site, in Richland, Washington. The maintenance shops repair and maintain vehicles and equipment used in support of the Hanford cleanup mission. There are three general mechanic shops and one auto body repair shop. The mechanics work on heavy equipment used in construction, cranes, commercial motor vehicles, passenger-type vehicles in addition to air compressors, generators, and farm equipment. Services include part fabrication, installation of equipment, repair and maintenance work in the engine compartment, and tire and brake services. Work performed at the auto body shop includes painting and surface preparation which involves applying body filler and sanding. 8-hour time-weighted-average samples were collected for benzene and noise exposure and task-based samples were collected for lead dust work activities involving painted metal surfaces. Benzene samples were obtained using 3M™ 3520 sampling badges and were analyzed for additional volatile organic compounds. These compounds were selected based on material safety data sheet information for the aerosol products used by the mechanics for each day of sampling. The compounds included acetone, ethyl ether, toluene, xylene, VM&P naphtha, methyl ethyl ketone, and trichloroethylene. Laboratory data for benzene, VM&P naphtha, methyl ethyl ketone and trichloroethylene were all below the reporting detection limit. Airborne concentrations for acetone, ethyl ether, toluene and xylene were all less than 10% of their occupational exposure limit. The task-based samples obtained for lead dusts were submitted for a metal scan analysis to identify other metals that might be present. Laboratory results for lead dusts were all below the reporting detection limit and airborne concentration for the other metals observed in the samples were less than 10% of the occupational exposure limit. Noise dosimetry sampling was performed on a random basis and was representative of the different work activities within the four shops. Twenty three percent of the noise samples exceeded the occupational exposure limit of 85 decibels for an 8-hour time-weightedaverage. Work activities where noise levels were higher included use of impact wrenches and grinding wheels.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Deep Borehole Field Test Requirements and Controlled Assumptions.

This document presents design requirements and controlled assumptions intended for use in the engineering development and testing of: 1) prototype packages for radioactive waste disposal in deep boreholes; 2) a waste package surface handling system; and 3) a subsurface system for emplacing and retrieving packages in deep boreholes. Engineering development and testing is being performed as part of the Deep Borehole Field Test (DBFT; SNL 2014a). This document presents parallel sets of requirements for a waste disposal system and for the DBFT, showing the close relationship. In addition to design, it will also inform planning for drilling, construction, and scientific characterization activities for the DBFT. The information presented here follows typical preparations for engineering design. It includes functional and operating requirements for handling and emplacement/retrieval equipment, waste package design and emplacement requirements, borehole construction requirements, sealing requirements, and performance criteria. Assumptions are included where they could impact engineering design. Design solutions are avoided in the requirements discussion. Deep Borehole Field Test Requirements and Controlled Assumptions July 21, 2015 iv ACKNOWLEDGEMENTS This set of requirements and assumptions has benefited greatly from reviews by Gordon Appel, Geoff Freeze, Kris Kuhlman, Bob MacKinnon, Steve Pye, David Sassani, Dave Sevougian, and Jiann Su.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

BER-Myriant Succinic Acid Biorefinery

Myriant Corporation (Myriant) has successfully produced the bioproduct succinic acid by the fermentation of glucose at a commercial scale operation in Lake Providence, Louisiana. The MySAB facility (Myriant Succinic Acid Biorefinery) came on stream in May 2013 and has been producing product since then. The MySAB facility is a demonstration-scale plant, capable of utilizing sorghum grits and commercially available dextrose, to ferment glucose into succinic acid. A downstream processing train has demonstrated the ability to produce an industrial, a standard and a polymer grade product. It consists of cell separation, membrane filtration, continuous chromatography, polishing to remove ionic and color bodies impurities, and final evaporation and crystallization. A by-product of the process is ammonium sulfate which is sold as a liquid fertilizer product. Since 2007 when development work began in the Woburn, Massachusetts R&D laboratories, the succinic acid bio-process has evolved through: Process development (microbiology, fermentation, and downstream) – R&D development laboratories; Piloting efforts at Fermic S.A. de C.V., Mexico City, Mexico – upstream and downstream processes; Design, construction, commissioning, and commercial production operations at the MySAB facility Additionally, Myriant became a wholly-owned subsidiary of the PTT Global Chemical Plc., Thailand, in late 2015, their investment into and support of Myriant goes back to 2011. The support of PTT Global Chemical Plc. helped to improve the upstream and downstream processes, and produce significant metric ton quantities of high quality bio-based succinic acid. The product has gone into a number of commercial markets worldwide for customer applications, development and production. The experience base gained via operations at the MySAB facility since May 2013, along with continued R&D development efforts involving Microbiology, Fermentation, and Downstream processes, at both the Woburn, Massachusetts and PTT Global Chemical Plc. Thailand laboratories, positions the company well for future production at the plant and commercialization of new bio-based products. This will be especially important and valuable as the green chemistry business climate continues to take root and flourish.

09 BIOMASS FUELS↗
DOE OSTI2019

The Potential Role of Concentrating Solar Power within the Context of DOE's 2030 Solar Cost Targets

To continue the momentum for cost reduction in solar technologies, DOE recently established 2030 cost targets for that would make solar one of the lowest-cost sources of new electricity in the United States. The potential impacts of achieving the 2030 cost targets for solar photovoltaics (PV) were recently explored in a related publication, which found significant potential for solar PV deployment and generation, particularly when coupled with low-cost storage. Building on this previous report, the present analysis evaluates the potential impacts of simultaneously achieving the 2030 cost targets for both PV and concentrating solar power with thermal energy storage (CSP-TES) systems in the contiguous United States, with a detailed evaluation of the role that CSP-TES plays in realizing those impacts. The evolution of the contiguous U.S. electricity system is evaluated with NREL's Renewable Energy Deployment System (ReEDS) model, which has been specifically designed to represent the time and locational value of renewable generation technologies in the U.S. power system. This analysis suggests achievement of the SunShot cost targets for CSP-TES might lead to dramatic growth in CSP-TES capacity, with accelerated deployment after the 2030 target is achieved. Based on our representation of the 2030 cost targets in ReEDS, economically-competitive CSP-TES could primarily be deployed in a dispatch able, high-capacity factor configuration, which allows it to provide valuable services to the power sector and results in a generation profile for CSP-TES that is complementary to that of variable PV. Aggressive cost reductions for CSP-TES could also make such a configuration economically competitive across the contiguous United States, which is a a result that warrants additional analysis in terms of potential siting, permitting, regulatory, and construction challenges in these new regions and markets. The modeled capacity expansion of both CSP-TES and PV in our scenarios that achieve the 2030 cost targets requires most growth in transmission capacity at a pace that is consistent with historical buildout rates, and could result in reduced electricity prices and power system costs, water usage, and air emissions. Finally, sensitivity analysis suggests that the cumulative capacity and geographic extent of CSP-TES deployment in our low-cost solar scenarios is highly sensitive to the post-2030 cost reductions for CSP-TES and future price of natural gas, and that significant competition exists among renewable energy and energy storage technologies, assuming aggressive cost reductions for each. For example, significant competition between CSP-TES and PV with battery storage indicates the similar role that these systems play in capacity planning and grid operations, as well as the fact that low-cost battery storage would help improve the capacity value of low-cost PV into the future.

14 SOLAR ENERGY↗
DOE OSTI2025

Methods in PES-Learn: Direct-Fit Machine Learning of Born–Oppenheimer Potential Energy Surfaces

The release of PES-L EARN version 1.0 as an open-source software package for the automatic construction of machine learning models of semi-global molecular potential energy surfaces (PESs) is presented. Improvements to PES-L EARN ’s interoperability are stressed with new Python API that simplifies workflows for PES construction via interaction with QCSchema input and output infrastructure. In addition, a new machine learning method is introduced to PES-L EARN : kernel ridge regression (KRR). The capabilities of KRR are emphasized with examination of select semi-global PESs. All machine learning methods available in PES-L EARN are benchmarked with benzene and ethanol datasets from the rMD17 database to illustrate PES-L EARN ’s performance ability. Fitting performance and timings are assessed for both systems. Finally, the ability to predict gradients with neural network models is presented and benchmarked with ethanol and benzene. PES-L EARN is an active project and welcomes community suggestions and contributions.

kernel ridge regression↗
DOE OSTI2024

Lifting MGARD: Construction of (pre)wavelets on the interval using polynomial predictors of arbitrary order

MGARD (MultiGrid Adaptive Reduction of Data) is an algorithm for compressing and refactoring scientific data, based on the theory of multigrid methods. The core algorithm is built around stable multilevel decompositions of conforming piecewise linear $C^0$ finite element spaces, enabling accurate error control in various norms and derived quantities of interest. In this work, we extend this construction to arbitrary order Lagrange finite elements $\mathbb{Q}_p$, $p \geq 0$, and propose a reformulation of the algorithm as a lifting scheme with polynomial predictors of arbitrary order. Additionally, a new formulation using a compactly supported wavelet basis is discussed, and an explicit construction of the proposed wavelet transform for uniform dyadic grids is described.

Reshniak, Viktor [Oak Ridge National Laboratory (O↗
DOE OSTI2018

Molecular Models and Wave Function Definitions for Models A-G of the [2Fe]F Cluster in FeFe-hydrogenase Maturase Enzyme HydF

The dataset contains all relevant atomic positional coordinates for 2Fe-cluster models, and electronic wave function data (using formatted Gaussian checkpoint files) as described in the related publication (see citation below). The version 2.0 contains additional models for [2Fe-2S] cluster linked [2Fe]F constructs. The top folder contains "analysis.xlsx" electronic spreadsheet that summarizes all the numerical results for absolute and relative electronic energy values, internal coordinates, calculated and scaled vibrational frequencies for diatomic stretching modes. The details of developing scaled quantum forcefields as a function of level of theory and model composition are also given. The schematic structural definitions are given in the "models.pdf" file and keys for abbreviations are provided in "symbols.txt" file.

carbonyl stretching frequencies↗
DOE OSTI2018

Measurements of Scatter Peaks in 137 Cs and 60 Co Sources

Results from tests of radiation detection instruments with radionuclide identification capabilities will depend on the sources used for the tests. Radionuclide identification detectors are designed to measure photons and provide an identification of the source being measured. High-resolution spectra need to be acquired to determine all the observable peaks in the source spectra before testing these types of instruments. These peaks may be due to impurities and/or scatter peaks in the sources. This paper discusses the issues encountered with the response of a radioisotope identification device due to scatter peaks in one type of source used for testing. In addition, it provides spectra for different source types and source constructions to compare the differences in scatter, allowing for a better source type selection for instrument testing.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1972

Spacecraft charging at synchronous orbit.

Observation that ATS 5 can charge to potentials as high as 10,000 volts during eclipse, and as high as 200 volts in sunlight. This charging has been used to infer the presence of the plasmasphere at synchronous altitude in the midnight region, and its prompt disappearance when hot plasma is injected in association with substorms. Although injected plasma has a density of 1.0 per cu cm the remaining cold plasma (less than 50 eV) has a density of 0.01 per cu cm. A mathematical model of ATS 5 has been constructed that can be used to predict spacecraft potentials. In addition, parts of ATS 5 can charge to several hundred volts without affecting the overall spacecraft potential appreciably.

Deforest, S. E.↗
NASA NTRS1972

LSI computer design - SUMC/DV.

Advanced Technology Laboratories has designed, built, and tested the first CMOS general-purpose computer. The computer executes 32 instructions that are operation-code compatible with the IBM 360 and RCA Spectra 70 series of computers. The computer is supported by 2k words of main-memory LSI storage and a TTY peripheral for input and output operations. Additionally, a simulator, an assembler, and a loader have been constructed to provide software support to the hardware. This paper provides an overall picture of this computer project.

Clapp, W. A.↗
NASA NTRS1974

Neutral and ion exosphere models for lunar hydrogen and helium

A general neutral exosphere model, which includes density and temperature variations at the exobase, is applied to the moon to obtain surface and radial density distributions for H, H2, and He. It is assumed that the source for these constituents derives from accretion of solar wind ions. The surface distributions are determined by requiring that the sum of the neutral and solar wind ion fluxes for a given constituent vanish at all points on the surface. On this basis, maximum dayside surface densities for H, H2, and He and maximum nightside surface densities for H, H2, and He are obtained that are consistent with either measured values or upper limits. In addition, model ion density distributions for H2(+) and He(+) are constructed. This ion exosphere is produced by ionization of the neutral exosphere in the solar wind, which efficiently sweeps the ions past or onto the lunar surface. Saturated H2(+) and He(+) densities ranging from about .001 to .015 per cu cm and .00003 to .0004 per cu cm over 1.5 to 3 selenocentric radii on the dayside, respectively.

Hartle, R. E.↗