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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 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

EDRIXS: An open source toolkit for simulating spectra of resonant inelastic x-ray scattering

Resonant inelastic x-ray scattering (RIXS) has become a very powerful experimental technique to probe a broad range of intrinsic elementary excitations, for example, from low energy phonons and (bi-)magnons to high energy d-d, charge-transfer and plasmon excitations in strongly correlated electronic systems. Due to the complexity of the RIXS cross-section and strong core-hole effects, theoretical simulation of the experimental RIXS spectra is still a difficult task which hampers the understanding of RIXS spectra and the development of the RIXS technique. In this work, we present an open source toolkit (dubbed EDRIXS) to facilitate the simulations of RIXS spectra of strongly correlated materials based on exact diagonalization (ED) of certain model Hamiltonians. The model Hamiltonian can be from a single atom, small cluster or Anderson impurity model, with model parameters from density functional theory plus Wannier90 or dynamical mean-field theory calculations. The spectra of x-ray absorption spectroscopy (XAS) and RIXS are then calculated using Krylov subspace techniques. This toolkit contains highly efficient ED, XAS and RIXS solvers written in modern Fortran 90 language and a convenient Python library used to prepare inputs and set up calculations. We first give a short introduction to RIXS spectroscopy, and then we discuss the implementation details of this toolkit. Lastly, we show three examples to demonstrate its usage.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

GenASiS Basics: Object-oriented utilitarian functionality for large-scale physics simulations (Version 3)

GenASiS Basics provides Fortran 2003 classes furnishing extensible object-oriented utilitarian functionality for large-scale physics simulations on distributed memory supercomputers. This functionality includes physical units and constants; display to the screen or standard output device; message passing; I/O to disk; and runtime parameter management and usage statistics. This revision – Version 3 of Basics – includes a significant name change, some minor additions to functionality, and a major addition to functionality: infrastructure facilitating the offloading of computational kernels to devices such as GPUs.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Simulating low-energy neutrino interactions with MARLEY

Monte Carlo event generators are a critical tool for the interpretation of data obtained by neutrino experiments. Several modern event generators are available which are well-suited to the GeV energy scale used in studies of accelerator neutrinos. However, theoretical modeling differences make their immediate application to lower energies difficult. In this paper, I present a new event generator, MARLEY, which is designed to better address the simulation needs of the low-energy (tens of MeV and below) neutrino community. The code is written in C++14 with an optional interface to the popular ROOT data analysis framework. The current release of MARLEY (version 1.2.0) emphasizes simulations of the reaction 40 Ar ( ν e , e − ) 40 K ⁎ but is extensible to other channels with suitable user input. This paper provides detailed documentation of MARLEY's implementation and usage, including guidance on how generated events may be analyzed and how MARLEY may be interfaced with external codes such as Geant4. Further information about MARLEY is available on the official website at http://www.marleygen.org. Program title:MARLEY 1.2.0 CPC Library link to program files:https://doi.org/10.17632/4v7zxnc8j3.1 Developer's respository link:http://github.com/MARLEY-MC/marley Code Ocean capsule:https://codeocean.com/capsule/9868179 Licensing provisions: GNU General Public License 3.0 Programming language: C++14 External routines/libraries used: GNU Scientific Library [1,2] (required), ROOT [3,4] (optional) Nature of problem: Simulation of neutrino-nucleus scattering events at energies of tens-of-MeV and below Solution method: Initial two-to-two scattering kinematics are sampled using the allowed approximation differential cross section and tables of precomputed nuclear matrix elements. Subsequent de-excitations of the remnant nucleus are simulated using a Monte Carlo implementation of the Hauser-Feshbach statistical model and tabulated γ-ray decay schemes for discrete nuclear levels. Additional comments including restrictions and unusual features: Input data are provided with the code that are suitable for producing simulations of the charged-current reaction 40 Ar ( ν e , e − ) 40 K ⁎ , coherent elastic neutrino-nucleus scattering on spin-zero target nuclei, and neutrino-electron elastic scattering on any atomic target. Preparation of new reaction input files (whose format is documented in Appendix B) would enable other reaction channels and nuclear targets to be handled by the existing code framework. Although there is no maximum neutrino energy enforced by the code itself, realistic neutrino-nucleus scattering events may be generated up to roughly 50 MeV. Above this energy, the effects of forbidden nuclear transitions, which are neglected in the current treatment of the cross sections (see section 2.1), become increasingly important.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

De-noising drift chambers in CLAS12 using convolutional auto encoders

Modern Nuclear Physics experimental setups run experiments with higher beam intensity resulting in increased noise in detector components used for particle track reconstruction. Increased uncorrelated signals (noise) result in decreased particle reconstruction efficiency. In this paper, we investigate the usage of Machine Learning, specifically Convolutional Neural Network Auto-Encoders (CAE), for de-noising raw hits from drift chambers in the CLAS12 detector. To the best of our knowledge, this is the first time CAE is employed to perform such an operation in this field. During the de-noising phase, it is important to remove as much noise as possible while retaining the valid hits to avoid losing crucial information about the experiment. Here, we show that using CAE, it is possible to remove noise hits while retaining up to 94% of valid tracks for a beam current of 110nA while for lower beam currents (45-55nA), we get up to 98% efficiency. Studies on experimental conditions with increasing noise show that CAE performs better than conventional tracking algorithms in isolating hits belonging to tracks. Specifically, the de-noising algorithm results in tracking efficiency improvements greater than 15%, in real data production procedures with nominal conditions, and up to two times better efficiency in synthetically generated data with high luminosity conditions (90-110nA), indicating that machine learning can lead to significantly shorter times for conducting physics experiments.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

GenASiS Basics: Object-oriented utilitarian functionality for large-scale physics simulations (Version 4)

GenASiS Basics provides modern Fortran classes furnishing extensible object-oriented utilitarian functionality for large-scale physics simulations on distributed memory supercomputers. This functionality includes physical units and constants; display to the screen or standard output device; message passing; I/O to disk; and runtime parameter management and usage statistics. Herein, this revision—Version 4 of Basics—includes a name change and additions to functionality, including the facilitation of direct communication between GPUs.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

Fantômas unconfined: global QCD fits with Bézier parameterizations

Fantômas is a C++ toolkit for exploring the parametrization dependence of parton distribution functions (PDFs) and other correlator functions in quantum chromodynamics (QCD). Fantômas facilitates the generation of adaptable polynomial parametrizations for PDFs, called metamorphs, to find best-fit PDF solutions and quantify the epistemic uncertainty associated with the parametrizations during their fitting. The method employs Bézier curves as universal approximators for a variety of PDF shapes. Integrated into the xFitter framework for the global QCD analysis, Fantômas provides a foundation for general models of PDFs, while reducing the computational time compared to the approaches utilizing traditional polynomial parametrizations as well as providing an interpretable alternative to neural-network-based models. This paper outlines the structure and practical usage of the Fantômas toolkit, including its inputs, outputs, and implementation within xFitter. It also provides a practical example of using Fantômas for uncertainty quantification as well as the combination of PDF fits into a single ensemble.

Bézier curves↗
DOE OSTI2024

Challenges in the mechanical recycling and upcycling of mixed postconsumer recovered plastics (PCR): A review

The presence of chemically different and compositionally varying plastics in mixed postconsumer recovered plastic (PCR) presents daunting barriers to recycling and upcycling efforts. This review systematically outlines how different processing techniques and characterization methods can be implemented to improve PCR's mechanical recycling and upcycling processes. The review further addresses the recycling challenges in the processing of mixed plastics from PCR and how their mechanical properties can be enhanced by making use of different types of compatibilizers such as copolymers, Janus nanoparticles as well as different approaches such as solid-state pulverization and microfibrillarization. In addition, the state-of-the-art applications of recycled plastics usage in automotive and construction are reviewed.

Compatibilization↗
DOE OSTI2020

Quantifying cover crop effects on soil health and productivity

The dataset presented here supports the research paper entitled “A calculator to quantify cover crop effects on soil health and productivity”. Soil health (sometimes used synonymously with soil quality) is a concept that describes soil as a living system to sustain plants, animals, and human. Soil physical, chemical, and biological properties, along with their interactions, are required to quantify soil health. The use of cover crops in agricultural rotations may enhance soil health, yet there has been little progress in understanding how external factors such as climate, soil type, and agronomic practices affect soil and cash crop responses. In response, this dataset compiles measurements from 281 studies and provides an analysis of field-measured changes in 38 soil health indicators due to cover crop usage. Environmental and background indicators were also compiled to assess how climatic and management practices affect soil and cash crop responses to cover crops, with specific categories including climate type (tropical, arid, temperate, and continental), soil texture (coarse, medium, and fine), cover crop type (legume, grass, multi-species mixture, and other), and cash crop type (corn, soybean, wheat, vegetable, corn-soybean rotation, corn-soybean-wheat rotation, and other). An unbalanced analysis of variation was used to determine the hierarchy of most to least important factors that affected responsiveness of each soil health indicator. Based on the hierarchy structure, a soil health calculator was then developed to quantify the response of 13 parameters – erosion, runoff, weed suppression, soil aggregate stability, leaching, infiltration, microbial biomass carbon, soil bulk density, soil organic carbon, soil nitrogen, microbial biomass nitrogen, cash crop yield, and saturated hydraulic conductivity – to cover crops. The presented data in the calculator report the mean change in parameter values based on all combinations of climate, soil texture, cover crop type, and cash crop type.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Fused ring non-fullerene acceptors with benzothiophene dioxide end groups and their side chain effect investigations

The development of small molecule-based non-fullerene acceptors (NF-SMAs) greatly advanced the performances of polymer solar cells (PSCs) in recent years. As the foreseeability of commercializing this technology in the future, interest in reducing the materials cost is rising. To this end, efforts have been made in this work on exploring the usage of commercially available chemical segment of benzothiophene dioxide (BC) in constructing efficient NF-SMAs. Thus, we designed and synthesized two BC-based NF-SMAs, which showed high power conversion efficiency (PCE) of 7.59% also by device engineering and side chain engineering. Our work revealed the full potential of using BC end groups in constructing high-performance NF-SMAs and demonstrated the application of side chain engineering in tuning material properties and performances.

36 MATERIALS SCIENCE↗
DOE OSTI2024

The role of the iron and steel sector in achieving net zero U.S. CO 2 emissions by 2050

The U.S. steel sector is a hard-to-abate sector because of its heavy dependence on fossil fuels and its high capital requirements. In 2015, the sector was one of the major carbon emitters, contributing 10 % of the U.S. industrial CO 2 emissions. The ability to decarbonize the U.S. iron and steel sector directly affects the ability of the U.S. to achieve economy-wide net zero CO 2 by 2050. In this paper, we use the Global Change Analysis Model (GCAM) to analyze different U.S. steel sector decarbonization pathways under varying technology, policy, and demand futures. These pathways provide insights on how various low-carbon steelmaking technologies such as those using carbon capture and storage (CCS), hydrogen, or scrap could help reduce U.S. steel emissions by mid-century. In our primary decarbonization pathway, we find that nearly all of the conventional fossil-based steelmaking capacity is fully integrated with CCS by 2050. However, without CCS availability, almost all of the conventional fossil-based steelmaking is phased-out by 2050 and is replaced by hydrogen-based production. Scrap-based production continues to remain vital across both of these decarbonization pathways. Furthermore, we find that demand reduction could help reduce the required levels of CCS and hydrogen-based production in the decarbonization pathways. Implementation of advanced energy efficiency measures could help substantially reduce the sector's energy usage. Finally, we observe that addressing the embodied carbon transfer associated with steel imports will be crucial for fully decarbonizing the U.S. steel sector.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Climate mitigation’s impact on global and regional electric power sector water use in the 21st Century

Over the course of this coming century, global electricity use is expected to grow at least five fold and if stringent greenhouse gas emissions controls are in place the growth could be more than seven fold from current levels. Given that the electric power sector represents the second largest anthropogenic use of water and given growing concerns about the nature and extent of future water scarcity driven by population growth and a changing climate, significant concern has been expressed about the electricity sector’s use of water going forward. In this paper, the authors demonstrate that an often overlooked but absolutely critical issue that needs to be taken into account in discussions about the sustainability of the electric sector’s water use going forward is the tremendous turn over in electricity capital stock that will occur over the course of this century; i.e., in the scenarios examined here more than 80% of global electricity production in the year 2050 is from facilities that have not yet been built. The authors show that because of the large scale changes in the global electricity system, the water withdrawal intensity of electricity production is likely to drop precipitously with the result being relatively constant water withdrawals over the course of the century even in the face of the large growth in electricity usage. The ability to cost effectively reduce the water intensity of power plants with carbon dioxide capture and storage systems in particular is key to constraining overall global water use.

carbon dioxide capture and storage↗
DOE OSTI2011

Assessing the cumulative effects of projects using geographic information systems

Systems that allow users to store and retrieve spatial data, provide for analyses of spatial data, and offer highly detailed display of spatial data are referred to as geographic information systems, or more typically, GIS. Since their initial usage in the 1960s, GISs have evolved as a means of assembling and analyzing diverse data pertaining to specific geographical areas, with spatial locations of the data serving as the organizational basis for the information systems. The structure of GISs is built around spatial identifiers and the methods used to encode data for storage and manipulation. This paper examines how GIS has been used in typical environmental assessment, its use for cumulative impact assessment, and explores litigation that occurred in the United States Federal court system where GIS was used in some aspect of cumulative effects. The paper also summarizes fifteen case studies that range from area wide transportation planning to wildlife and habitat impacts, and draws together a few lessons learned from this review of literature and litigation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Knowledge, data and interests: Challenges in participation of diverse stakeholders in HIA

Stakeholder participation is considered an integral part of HIA. However, the challenges that participation implies in a multi-disciplinary and multi-ethnic society are less studied. This paper presents the manifestations of the multiplicity of sectors and population groups in HIA and discusses the challenges that such diversity imposes. Specifically, there is no common ground between participants, as their positions entail contradictory knowledge regarding the current situation, reliance on distinct data and conflicting interests. This entails usage of multiple professional and ethnic languages, disagreements regarding the definition of health and prioritizing health issues in HIA, and divergent perceptions of risk. These differences between participants are embedded culturally, socially, individually and, maybe most importantly, professionally. This complex picture of diverse stakeholder attributes is grounded in a case study of stakeholder participation in HIA, regarding zoning of a hazardous industry site in Israel. The implication is that participatory HIAs should address the multiplicity of stakeholders and types of knowledge, data and interests in a more comprehensive way. - Highlights: Black-Right-Pointing-Pointer This paper analyses challenges in participation of diverse stakeholders in HIA. Black-Right-Pointing-Pointer The multiplicity of disciplines and population groups raises fundamental challenges. Black-Right-Pointing-Pointer Stakeholders possess distinct and often contradictory knowledge, data and interests. Black-Right-Pointing-Pointer They speak different languages, and differ on approaches to health and risk perceptions. Black-Right-Pointing-Pointer Substantial amendments to diverse participation are needed, in HIA and generally.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Baseline effects on carbon footprints of biofuels: The case of wood

As biofuel usage has boomed over the past decade, so has research and regulatory interest in its carbon accounting. This paper examines one aspect of that carbon accounting: the baseline, i.e. the reference case against which other conditions or changes can be compared. A literature search and analysis identified four baseline types: no baseline; reference point; marginal fossil fuel; and biomass opportunity cost. The fourth one, biomass opportunity cost, is defined in more detail, because this is not done elsewhere in the literature. The four baselines are then applied to the carbon footprint of a wood-fired power plant. The footprint of the resulting wood-fired electricity varies dramatically, according to the type of baseline. Baseline type is also found to be the footprint's most significant sensitivity. Other significant sensitivities are: efficiency of the power plant; the growth (or re-growth) rate of the forest that supplies the wood; and the residue fraction of the wood. Length of the policy horizon is also an important factor in determining the footprint. The paper concludes that because of their significance and variability, baseline choices should be made very explicit in biofuel carbon footprints. - Highlights: Black-Right-Pointing-Pointer Four baseline types for biofuel footprinting are identified. Black-Right-Pointing-Pointer One type, 'biomass opportunity cost', is defined mathematically and graphically. Black-Right-Pointing-Pointer Choice of baseline can dramatically affect the footprint result. Black-Right-Pointing-Pointer The 'no baseline' approach is not acceptable. Black-Right-Pointing-Pointer Choice between the other three baselines depends on the question being addressed.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Addressing trend-related changes within cumulative effects studies in water resources planning

Summarized herein are 28 case studies wherein trend-related causative physical, social, or institutional changes were connected to consequential changes in runoff, water quality, and riparian and aquatic ecological features. The reviewed cases were systematically evaluated relative to their identified environmental effects; usage of analytical frameworks, and appropriate models, methods, and technologies; and the attention given to mitigation and/or management of the resultant causative and consequential changes. These changes also represent important considerations in project design and operation, and in cumulative effects studies associated therewith. The cases were grouped into five categories: institutional changes associated with legislation and policies (seven cases); physical changes from land use changes in urbanizing watersheds (eight cases); physical changes from land use changes and development projects in watersheds (four cases); physical, institutional, and social changes from land use and related policy changes in river basins (three cases); and multiple changes within a comprehensive study of land use and policy changes in the Willamette River Basin in Oregon (six cases). A tabulation of 110 models, methods and technologies used in the studies is also presented. General observations from this review were that the features were unique for each case; the consequential changes were logically based on the causative changes; the analytical frameworks provided relevant structures for the studies, and the identified methods and technologies were pertinent for addressing both the causative and consequential changes. One key lesson was that the cases provide useful, “real-world” illustrations of the importance of addressing trend-related changes in cumulative effects studies within water resources planning. Accordingly, they could be used as an “initial tool kit” for addressing trend-related changes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

A state-impact-state methodology for assessing environmental impact in land use planning

The implementation of land use planning (LUP) has a large impact on environmental quality. There lacks a widely accepted and consolidated approach to assess the LUP environmental impact using Strategic Environmental Assessment (SEA). In this paper, we developed a state-impact-state (SIS) model employed in the LUP environmental impact assessment (LUPEA). With the usage of Matter-element (ME) and Extenics method, the methodology based on the SIS model was established and applied in the LUPEA of Zoucheng County, China. The results show that: (1) this methodology provides an intuitive and easy understanding logical model for both the theoretical analysis and application of LUPEA; (2) the spatial multi-temporal assessment from base year, near-future year to planning target year suggests the positive impact on the environmental quality in the whole County despite certain environmental degradation in some towns; (3) besides the spatial assessment, other achievements including the environmental elements influenced by land use and their weights, the identification of key indicators in LUPEA, and the appropriate environmental mitigation measures were obtained; and (4) this methodology can be used to achieve multi-temporal assessment of LUP environmental impact of County or Town level in other areas. - Highlights: • A State-Impact-State model for Land Use Planning Environmental Assessment (LUPEA). • Matter-element (ME) and Extenics methods were embedded in the LUPEA. • The model was applied to the LUPEA of Zoucheng County. • The assessment shows improving environment quality since 2000 in Zoucheng County. • The method provides a useful tool for the LUPEA in the county level.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Extending cost–benefit analysis for the sustainability impact of inter-urban Intelligent Transport Systems

The paper reports research involving three cost–benefit analyses performed on different ITS schemes (Active Traffic Management, Intelligent Speed Adaptation and the Automated Highway System) on one of the UK's busiest highways — the M42. The environmental scope of the assets involved is widened to take into account the possibility of new technology linked by ICT and located within multiple spatial regions. The areas focused on in the study were data centre energy emissions, the embedded emissions of the road-side infrastructure, vehicle tailpipe emissions, additional hardware required by the vehicles (if applicable) and safety, and all aspects of sustainability. Dual discounting is applied which aims to provide a separate discount rate for environmental elements. For ATM, despite the energy costs of the data centre, the initial implementation costs and mitigation costs of its embedded emissions, a high cost–benefit ratio of 5.89 is achieved, although the scheme becomes less effective later on its lifecycle due to rising costs of energy. ISA and AHS generate a negative result, mainly due to the cost of getting the vehicle on the road. In order to negate these costs, the pricing of the vehicle should be scaled depending upon the technology that is outfitted. Retrofitting on vehicles without the technology should be paid for by the driver. ATM will offset greenhouse gas emissions by 99 kt of CO{sub 2} equivalency over a 25 year lifespan. This reduction has taken into account the expected improvement in vehicle technology. AHS is anticipated to save 280 kt of CO{sub 2} equivalency over 15 years of operational usage. However, this offset is largely dependent on assumptions such as the level of market penetration. - Highlights: • Three cost–benefit analyses are applied to inter-urban intelligent transport. • For ATM, a high cost–benefit ratio of 5.89 is achieved. • ATM offsets greenhouse gas emissions by 99 kt of CO{sub 2} equivalency over 25 years. • ISA and AHS generate a negative result due to vehicle implementation costs. • AHS is anticipated to save 280 kt of CO{sub 2} equivalency over 15 years.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Life cycle thinking in impact assessment—Current practice and LCA gains

It has been advocated that life cycle thinking (LCT) should be applied in impact assessment (IA) to a greater extent, since some development proposals pose a risk of significant impacts throughout the interconnected activities of product systems. Multiple authors have proposed the usage of life cycle assessment (LCA) for such analytical advancement, but little to no research on this tool application has been founded in IA practice so far. The aim of this article is to elaborate further on the gains assigned to application of LCA. The research builds on a review of 85 Danish IA reports, which were analysed for analytical appropriateness and application of LCT. Through a focus on the non-technical summary, the conclusion and the use of specific search words, passages containing LCT were searched for in each IA report. These passages were then analysed with a generic framework. The results reveal that LCT is appropriate for most of the IAs, but that LCA is rarely applied to provide such a perspective. Without LCA, the IAs show mixed performance in regard to LCT. Most IAs do consider the product provision of development proposals, but they rarely relate impacts to this function explicitly. Many IAs do consider downstream impacts, but assessments of upstream, distant impacts are generally absent. It is concluded that multiple analytical gains can be attributed to greater application of LCA in IA practice, though some level of LCT already exists. - Highlights: • Life cycle thinking is appropriate across the types and topics of impact assessment. • Yet, life cycle assessment is rarely used for adding such perspective. • Impact assessment practice does apply some degree of life cycle thinking. • However, application of life cycle assessment could bring analytical gains.

54 ENVIRONMENTAL SCIENCES↗