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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Characterization and Potential Remediation Approaches for Vadose Zone Contamination at Hanford 241-SX Tank Farm - 13235

Unplanned releases of radioactive and hazardous wastes have occurred at the 241-SX Tank Farm on the U.S. Department of Energy Hanford Site in southeast Washington State. Interim and long-term mitigation efforts are currently under evaluation for 241-SX Tank Farm. Two contiguous interim surface barriers have been designed for deployment at 241-SX Tank Farm to reduce future moisture infiltration; however, construction of the surface barriers has been deferred to allow testing of alternative technologies for soil moisture reduction and possibly contaminant source term reduction. Previous tests performed by other organizations at the Hanford Site have demonstrated that: vadose zone desiccation using large diameter (greater than 4 inch) boreholes is feasible; under certain circumstances, mobile contaminants may be removed in addition to water vapor; and small diameter (approximately 2 inch) boreholes (such as those placed by the direct push hydraulic hammer) can be used to perform vapor extractions. Evaluation of the previous work combined with laboratory test results have led to the design of a field proof-of-principle test to remove water and possibly mobile contaminants at greater depths, using small boreholes placed with the direct push unit. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Clean Cities 2015 Annual Metrics Report

The U.S. Department of Energy's (DOE's) Clean Cities program advances the nation's economic, environmental, and energy security by supporting local actions to cut petroleum use and greenhouse gas (GHG) emissions in transportation. A national network of nearly 100 Clean Cities coalitions, whose territory covers 80% of the U.S. population, brings together stakeholders in the public and private sectors to deploy alternative and renewable fuels, idle-reduction (IR) measures, fuel economy improvements, and new transportation technologies as they emerge. Each year, DOE asks Clean Cities coordinators to submit annual reports of their activities and accomplishments for the previous calendar year. Progress reports and information are submitted online as a function of the Alternative Fuels Data Center (AFDC) at the National Renewable Energy Laboratory (NREL). Coordinators report a range of information that characterize the membership, funding, projects, and activities of their coalitions. They also document activities in their region related to the development of refueling/charging infrastructure, sales of alternative fuels; deployment of alternative fuel vehicles (AFVs), plug-in electric vehicles (PEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); idle reduction initiatives; fuel economy improvement activities; and programs to reduce vehicle miles traveled (VMT). NREL analyzes the data and translates them into petroleum-use and GHG emission reduction impacts, which are summarized in this report.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2014

Building Partnerships to Cut Petroleum Use in Transportation (Brochure)

The U.S. Department of Energy's Clean Cities initiative advances the nation's economic, environmental, and energy security by supporting local actions to cut petroleum use in transportation. Clean Cities accomplishes this work through the activities of nearly 100 local coalitions. These coalitions provide resources and technical assistance in the deployment of alternative and renewable fuels, idle-reduction measures, fuel economy improvements, and new transportation technologies as they emerge.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2019

Clean Cities Coalitions: Advancing Affordable, Domestic Transportation Fuels and Technologies Across the Country

This fact sheet provides an overview of the U.S. Department of Energy's (DOE's) Vehicle Technologies Office Clean Cities coalitions, which advance affordable, domestic transportation fuels and technologies nationwide. Nearly 100 coalitions serve as the foundation of Clean Cities, working in communities across the country to help local decision makers and fleets understand and implement alternative and renewable fuels, idle-reduction measures, fuel economy improvements, new mobility choices, and emerging transportation technologies. At the national level, VTO develops and promotes publications, tools, and other unique resources to support coordinators. At the local level, coalitions leverage these resources to create networks of stakeholders.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

Activating Single‐Atom Ni Site via First‐Shell Si Modulation Boosts Oxygen Reduction Reaction

Abstract Atomically dispersed nitrogen‐coordinated 3d transition‐metal site on carbon support (M‐NC) are promising alternatives to Pt group metal‐based catalysts toward oxygen reduction reaction (ORR). However, despite the excellent activities of most of M‐NC catalysts, such as Fe‐NC, Co‐NC et al., their durability is far from satisfactory due to Fenton reaction. Herein, this work reports a novel Si‐doped Ni‐NC catalyst (Ni‐SiNC) that possesses high activity and excellent stability. X‐ray absorption fine structure and aberration‐corrected transmission electron microscopy uncover that the single‐atom Ni site is coordinated with one Si atom and three N atoms, constructing Ni‐Si 1 N 3 moiety. The Ni‐SiNC catalyst exhibits a half‐wave potential (E 1/2 ) of 0.866 V versus RHE, with a distinguished long‐term durability in alkaline media of only 10 mV negative shift in E 1/2 after 35 000 cycles, which is also validated in Zn‐air battery. Density functional theory calculations reveal that the Ni‐Si 1 N 3 moiety facilitates ORR kinetics through optimizing the adsorption of intermediates.

Chemistry↗
DOE OSTI2021

Clean Cities Coalitions: Advancing Affordable, Domestic Transportation Fuels and Technologies Across the Country

This fact sheet provides an overview of the U.S. Department of Energy's (DOE's) Office of Energy Efficiency and Renewable Energy's Vehicle Technologies Office Clean Cities coalitions, which advance affordable, domestic transportation fuels and technologies nationwide. Nearly 100 coalitions serve as the foundation of Clean Cities, working in communities across the country to help local decision makers and fleets understand and implement alternative and renewable fuels, idle-reduction measures, fuel economy improvements, new mobility choices, and emerging transportation technologies. At the national level, VTO develops and promotes publications, tools, and other unique resources to support coordinators. At the local level, coalitions leverage these resources to create networks of stakeholders.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Clean Cities Coalitions: Advancing Affordable, Domestic Transportation Fuels and Technologies Across the Country

This fact sheet provides an overview of the U.S. Department of Energy's (DOE's) Office of Energy Efficiency and Renewable Energy's Vehicle Technologies Office Clean Cities coalitions, which advance affordable, domestic transportation fuels and technologies nationwide. Nearly 100 coalitions serve as the foundation of Clean Cities, working in communities across the country to help local decision makers and fleets understand and implement alternative and renewable fuels, idle-reduction measures, fuel economy improvements, new mobility choices, and emerging transportation technologies. At the national level, VTO develops and promotes publications, tools, and other unique resources to support coordinators. At the local level, coalitions leverage these resources to create networks of stakeholders.

47 OTHER INSTRUMENTATION↗
DOE OSTI2012

Impact of using linear optimization models in dose planning for HDR brachytherapy

Purpose: Dose plans generated with optimization models hitherto used in high-dose-rate (HDR) brachytherapy have shown a tendency to yield longer dwell times than manually optimized plans. Concern has been raised for the corresponding undesired hot spots, and various methods to mitigate these have been developed. The hypotheses upon this work is based are (a) that one cause for the long dwell times is the use of objective functions comprising simple linear penalties and (b) that alternative penalties, as these are piecewise linear, would lead to reduced length of individual dwell times. Methods: The characteristics of the linear penalties and the piecewise linear penalties are analyzed mathematically. Experimental comparisons between the two types of penalties are carried out retrospectively for a set of prostate cancer patients. Results: When the two types of penalties are compared, significant changes can be seen in the dwell times, while most dose-volume parameters do not differ significantly. On average, total dwell times were reduced by 4.2%, with a reduction of maximum dwell times by 25%, when the alternative penalties were used. Conclusions: The use of linear penalties in optimization models for HDR brachytherapy is one cause for the undesired long dwell times that arise in mathematically optimized plans. By introducing alternative penalties, a significant reduction in dwell times can be achieved for HDR brachytherapy dose plans. Although various measures for mitigating the long dwell times are already available, the observation that linear penalties contribute to their appearance is of fundamental interest.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Mechanism of N 2 Reduction Catalyzed by Fe-Nitrogenase Involves Reductive Elimination of H 2

Of the three forms of nitrogenase (Mo-nitrogenase, V-nitrogenase, and Fe-nitrogenase), Fe-nitrogenase has the poorest ratio of N 2 reduction relative to H 2 evolution. Current work on the Mo-nitrogenase has revealed that reductive elimination of two bridging Fe–H–Fe hydrides on the active site FeMo-cofactor to yield H 2 is a key feature in the N 2 reduction mechanism. The N 2 reduction mechanism for the Fe-nitrogenase active site FeFe-cofactor was unknown. Here, we have purified both component proteins of the Fe-nitrogenase system, the electron-delivery Fe protein (AnfH) plus the catalytic FeFe protein (AnfDGK), and established its mechanism of N 2 reduction. Inductively coupled plasma optical emission spectroscopy and mass spectrometry illustrate that the FeFe protein component does not contain significant amounts of Mo or V, thus ruling out a requirement of these metals for N 2 reduction. The fully functioning Fe-nitrogenase system was found to have specific activities for N 2 reduction (1 atm) of 181 ± 5 nmol NH 3 min –1 mg –1 FeFe protein, for proton reduction (in the absence of N 2 ) of 1085 ± 41 nmol H 2 min –1 mg –1 FeFe protein, and for acetylene reduction (0.3 atm) of 306 ± 3 nmol C 2 H 4 min –1 mg –1 FeFe protein. Under turnover conditions, N 2 reduction is inhibited by H 2 and the enzyme catalyzes the formation of HD when presented with N 2 and D 2 . These observations are explained by the accumulation of four reducing equivalents as two metal-bound hydrides and two protons at the FeFe-cofactor, with activation for N 2 reduction occurring by reductive elimination of H 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Photonuclear Contributions to SNS Pulse Shapes

Short-pulsed sources like the Spallation Neutron Source (SNS) and ISIS produce bursts of neutron pulses at rates of 10-60 Hz, with sub-microsecond proton pulses impacting on high-Z target materials. Moderators are grouped around the target to receive the fast neutrons generated from spallation reactions to moderate them effciently to thermal and sub-thermal energies and to feed narrow neutron pulses to neutron scattering instruments. The scattering instruments use the neutrons as a probe for material investigations, and make use of time-of-flight (TOF) methods for resolving the neutron energy. The energy resolution of scattering instruments depends on the narrow time-structure of the neutron pulses, while neutrons in the long tail of the emission time distributions can degrade the instrument performance and add undesired background to measurements. The SNS neutronics team is investigating a possible source term impacting the background at short-pulsed spallation sources. The ISIS TS2 project claims to have significantly reduced neutron scattering instrument background levels by the elimination or reduction of iron shielding in the target-moderator-reflector assembly. An alternative hypothesis, also proposed by ISIS, suggests that this apparent reduction arises from moving beamline shielding away from the neutron guide channels, reducing albedo down the beamlines. In both hypotheses, the background neutrons in question are believed to be generated by photonuclear reactions. If the background neutrons are indeed generated via photonuclear channels, then they are generated in a time-dependent fashion, since most of the high-energy photons capable of inducing photonuclear production are gone within a few microseconds following the proton pulse. To evaluate this e ect, we have enabled photonuclear reactions in a series of studies for the SNS first target station (FTS) taking advantage of its Monte Carlo model. Using a mixture of ENDF/B VII.0 and TENDL-2014 photonuclear cross sections available and the CEM03 physics model within MCNPX 2.6.0 in the simulation, we are able to estimate the impact of photoneutron production on both overall neutron production and delayed neutron production. We find that a significant number of photon-induced neutrons are produced a few milliseconds after the proton pulse, following prompt gamma emission through the capture of neutrons in the slowing-down and thermalization processes. We name these "slowing-down delayed neutrons" to distinguish them from either "activation-delayed neutrons" or "beta-delayed neutrons." The beta-delayed and activation-delayed neutrons were not part of this study, and will be addressed elsewhere. While these other delayed neutron channels result in the time-independent (constant) production of fast neutrons outside of the prompt pulse, the slowing-down delayed neutrons also a ect the shape of the pulses. Although numerically insignificant in most cases, we describe a set of scenarios related to T0-chopper operation in which the slowing-down delayed neutrons may be important.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Temporal dynamics of CO 2 and CH 4 loss potentials in response to rapid hydrological shifts in tidal freshwater wetland soils

Earth System Models predict climate extremes that will impact regional and global hydrology. Aquatic-terrestrial transition zones like wetlands are subjected to the immediate consequence of climate change with shifts in the magnitude and dynamics of hydrologic flow. Such fluctuating hydrology can alter the nature and rate of biogeochemical transformations and significantly impact the carbon balance of the ecosystem. We tested the impacts of fluctuating hydrology and, specifically, the role of antecedent moisture conditions in determining the dominant carbon loss mechanisms in soils sampled from a tidal freshwater wetland system in the lower Columbia River, WA, USA. Our objective was to understand shifts in biogeochemical processes in response to changing soil moisture, based on soil respiration and methane production rates, and to elucidate such responses based on the observed electron acceptor and metabolite profiles under laboratory conditions. Metabolomics and biogeochemical process rates provided evidence that soil redox was the principal factor driving metabolic function. Fluctuating redox conditions altered terminal electron acceptor and donor availability and recovery strengths of their concentrations in soil such that a disproportionate release of carbon dioxide stemmed from alternative anaerobic degradation processes like sulfate and iron reduction compared to carbon loss due to methano genesis. Our results show that extended and short-term saturation created conditions conducive to increasing metabolite availability for anaerobic decomposition processes, with a significant lag in methanogenesis. In contrast,extended drying caused a cellular-level stress response and rapid recycling of alternate electron acceptors.

anaerobic respiration, tidal wetlands, methane pro↗
DOE OSTI2015

Clean Cities Now, Vol. 18, No. 2

This is version 18.2 of Clean Cities Now, the official biannual newsletter of the Clean Cities program. Clean Cities is an initiative designed to reduce petroleum consumption in the transportation sector by advancing the use of alternative and renewable fuels, fuel economy improvements, idle-reduction measures, and new technologies, as they emerge.

advanced vehicles↗
DOE OSTI2015

Clean Cities Now Vol. 19, No. 1

Now is the official bi-annual newsletter of Clean Cities, an initiative designed to reduce petroleum consumption in the transportation sector by advancing the use of alternative and renewable fuels, fuel economy improvements, idle-reduction measures, and new technologies, as they emerge.

advanced vehicles↗
DOE OSTI2015

Clean Cities Now Vol. 19, No. 2

Clean Cities Now is the official bi-annual newsletter of Clean Cities, an initiative designed to reduce petroleum consumption in the transportation sector by advancing the use of alternative and renewable fuels, fuel economy improvements, idle-reduction measures, and new technologies, as they emerge.

advanced vehicles↗
DOE OSTI2022

Atomically Dispersed Pentacoordinated‐Zirconium Catalyst with Axial Oxygen Ligand for Oxygen Reduction Reaction

Single-atom catalysts (SACs), as promising alternatives to Pt-based catalysts, suffer from the limited choice of center metals and low single-atom loading. Here, we report a pentacoordinated Zr-based SAC with nontrivial axial O ligands (denoted O-Zr-N-C) for oxygen reduction reaction (ORR). The O ligand downshifts the d-band center of Zr and confers Zr sites with stable local structure and proper adsorption capability for intermediates. Consequently, the ORR performance of O-Zr-N-C prominently surpasses that of commercial Pt/C, achieving a half-wave potential of 0.91 V vs. reversible hydrogen electrode and outstanding durability (92% current retention after 130-hour operation). Moreover, the Zr site shows good resistance towards aggregation, enabling the synthesis of Zr-based SAC with high loading (9.1 wt%). With the high-loading catalyst, the zinc-air battery (ZAB) delivers a record-high power density of 324 mW cm -2 among those of SAC-based ZABs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

State and Alternative Fuel Provider Fleets - Fleet Compliance Annual Report: Model Year 2015, Fiscal Year 2016

The U.S. Department of Energy (DOE) regulates covered state government and alternative fuel provider fleets, pursuant to the Energy Policy Act of 1992 (EPAct), as amended. Covered fleets may meet their EPAct requirements through one of two compliance methods: Standard Compliance or Alternative Compliance. For model year (MY) 2015, the compliance rate with this program for the more than 3011 reporting fleets was 100%. More than 294 fleets used Standard Compliance and exceeded their aggregate MY 2015 acquisition requirements by 8% through acquisitions alone. The seven covered fleets that used Alternative Compliance exceeded their aggregate MY 2015 petroleum use reduction requirements by 46%.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Clean Cities Coalitions: 2016 Activity Report

The U.S. Department of Energy's (DOE's) national network of Clean Cities Coalitions advance the nation's economic, environmental, and energy security by supporting local actions to promote the use of domestic fuels within transportation. The nearly 100 Clean Cities coalitions, whose territory covers 80% of the U.S. population, bring together stakeholders in the public and private sectors to use alternative and renewable fuels, idle-reduction (IR) measures, fuel economy improvements, and new transportation technologies as they emerge. To ensure success, coalitions leverage a robust set of expert resources and tools provided by national laboratories and DOE. Each year, Clean Cities coordinators submit annual reports of their activities and accomplishments for the previous calendar year. Data and information are submitted via an online tool that is maintained as part of the Alternative Fuels Data Center (AFDC) at the National Renewable Energy Laboratory (NREL). Coordinators submit a range of data that characterize the membership, funding, projects, and activities of their coalitions. They also submit data about sales of alternative fuels; use of alternative fuel vehicles (AFVs), plug-in electric vehicles (PEVs), and hybrid electric vehicles (HEVs); IR initiatives; fuel economy improvement activities; and programs to reduce vehicle miles traveled (VMT). NREL analyzes the submitted data to determine how broadly energy use in the U.S. has shifted due to coalition activities, which are summarized in this report.

2016 metrics↗