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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 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Benchmarking embedded chain breaking in quantum annealing*

Quantum annealing solves combinatorial optimization problems by finding the energetic ground states of an embedded Hamiltonian. However, quantum annealing dynamics under the embedded Hamiltonian may violate the principles of adiabatic evolution and generate excitations that correspond to errors in the computed solution. Here we empirically benchmark the probability of chain breaks and identify sweet spots for solving a suite of embedded Hamiltonians. We further correlate the physical location of chain breaks in the quantum annealing hardware with the underlying embedding technique and use these localized rates in a tailored post-processing strategies. Our results demonstrate how to use characterization of the quantum annealing hardware to tune the embedded Hamiltonian and remove computational errors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Dynamical phase transition in a strongly hybridized phonon-triplon chain

In this article, we study a dimerized spin-1/2 chain, such as CuGeO 3 , hosting triplon excitations coupled to optical phonons under weak terahertz laser driving. Both phonons and triplons weakly lose energy into the surrounding baths, forming a non-equilibrium steady state. In the strong phonon-triplon coupling regime, phonons near the two-triplon continuum hybridize strongly with triplons. Using mean-field Lindblad dynamics, we show that strong hybridization induces sharp first-order phase transitions—either single or simultaneous double—in the emission spectrum, mainly due to nonlinearities in the chain and the instantaneous breaking of spatial inversion symmetry, as captured by the phonon displacement. Using mean-field Floquet analysis of harmonic modes in both sectors, we analytically confirm the existence of these phase transitions. Furthermore, we map the complete steady-state phase diagram by varying key control parameters and provide experimentally relevant parameters for observing these transitions in laser-driven CuGeO 3 .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

From Stress Chains to Acoustic Emission

A numerical scheme using the combined finite-discrete element method is employed to study a model of an earthquake system comprising a granular layer embedded in a formation. When the formation is driven so as to shear the granular layer, a system of stress chains emerges. The stress chains endow the layer with resistance to shear and on failure launch broadcasts into the formation. Furthermore, these broadcasts, received as acoustic emission, provide a remote monitor of the state of the granular layer of the earthquake system.

58 GEOSCIENCES↗
DOE OSTI2020

Superdiffusion from Emergent Classical Solitons in Quantum Spin Chains

Finite-temperature spin transport in the quantum Heisenberg spin chain is known to be superdiffusive, and has been conjectured to lie in the Kardar-Parisi-Zhang (KPZ) universality class. Using a kinetic theory of transport, we compute the KPZ coupling strength for the Heisenberg chain as a function of temperature, directly from microscopics; the results agree well with density-matrix renormalization group simulations. Here, we establish a rigorous quantum-classical correspondence between the “giant quasiparticles” that govern superdiffusion and solitons in the classical continuous Landau-Lifshitz ferromagnet. We conclude that KPZ universality has the same origin in classical and quantum integrable isotropic magnets: a finite-temperature gas of low-energy classical solitons.

1-dimensional spin chains↗
DOE OSTI2021

Phenomenology of Spectral Functions in Disordered Spin Chains at Infinite Temperature

Studies of disordered spin chains have recently experienced a renewed interest, inspired by the question to which extent the exact numerical calculations comply with the existence of a many-body localization phase transition. For the paradigmatic random field Heisenberg spin chains, many intriguing features were observed when the disorder is considerable compared to the spin interaction strength. Here, we introduce a phenomenological theory that may explain some of those features. The theory is based on the proximity to the noninteracting limit, in which the system is an Anderson insulator. Taking the spin imbalance as an exemplary observable, we demonstrate that the proximity to the local integrals of motion of the Anderson insulator determines the dynamics of the observable at infinite temperature. In finite interacting systems our theory quantitatively describes its integrated spectral function for a wide range of disorders.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Probabilistic Power Consumption Modeling for Commercial Buildings Using Logistic Regression Markov Chain

The total energy consumed by buildings takes up to 40% of U.S. energy use, in which a large portion is contributed by commercial buildings. Building performance optimization is desirable but requires accurate building models with uncertainties taken into account. This paper proposes a novel probabilistic modeling method using Logistic Regression Markov Chain (LRMC). The LRMC model enhances the performance of traditional Markov Chain (MC) models by adopting time-variant transition matrices calibrated using logistic regression with exogenous inputs. Compared with existing building models, the proposed model produces accurate multi-step modeling results with full probability distribution. The proposed probabilistic building model is tested using actual commercial building measurements and modeling performance is evaluated with two probabilisitc metrics. The results show that the LRMC model has higher accuracy than traditional MC model and Logistic Regression (LR) model in that it yields lower error scores under both evaluation metrics.

Building modeling↗
DOE OSTI2018

Regional Manufacturing Cost Structures and Supply Chain Considerations for Medium Voltage Silicon Carbide Power Applications

Bottoms-up cost analysis has been a mainstay of commoditized industry and manufacturing processes for years, however a holistic objective supply chain analysis to inform research and investment in the development of early stage technologies has not. The potential for rapid adoption of wide bandgap (WBG) semiconductors, specifically silicon carbide (SiC), highlights a need to understand the drivers of location-specific manufacturing cost, global supply chains, and plant location decisions. Further, ongoing research and investment, necessitates analytical analysis to help inform the roadmap of SiC technologies. In collaboration with PowerAmerica the project explores the bottoms-up cost analysis of wafers, devices, modules, and motor drives at the anticipated manufacturing levels. Leveraging these models, it outlines how the cost reduction potential of proposed research advances can be quantified.

42 ENGINEERING↗
DOE OSTI2022

Challenges in Markov Chain Monte Carlo for Bayesian Neural Networks

Markov chain Monte Carlo (MCMC) methods have not been broadly adopted in Bayesian neural networks (BNNs). This paper initially reviews the main challenges in sampling from the parameter posterior of a neural network via MCMC. Such challenges culminate to lack of convergence to the parameter posterior. Nevertheless, this paper shows that a nonconverged Markov chain, generated via MCMC sampling from the parameter space of a neural network, can yield via Bayesian marginalization a valuable posterior predictive distribution of the output of the neural network. Further, classification examples based on multilayer perceptrons showcase highly accurate posterior predictive distributions. The postulate of limited scope for MCMC developments in BNNs is partially valid; an asymptotically exact parameter posterior seems less plausible, yet an accurate posterior predictive distribution is a tenable research avenue.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

Crystal Structures of the Tetratricopeptide Repeat Domains of Kinesin Light Chains: Insight into Cargo Recognition Mechanisms

Kinesin-1 transports various cargos along the axon by interacting with the cargos through its light chain subunit. Kinesin light chains (KLC) utilize its tetratricopeptide repeat (TPR) domain to interact with over 10 different cargos. Despite a high sequence identity between their TPR domains (87%), KLC1 and KLC2 isoforms exhibit differential binding properties towards some cargos. We determined the structures of human KLC1 and KLC2 tetratricopeptide repeat (TPR) domains using X-ray crystallography and investigated the different mechanisms by which KLCs interact with their cargos. Using isothermal titration calorimetry, we attributed the specific interaction between KLC1 and JNK-interacting protein 1 (JIP1) cargo to residue N343 in the fourth TRP repeat. Structurally, the N343 residue is adjacent to other asparagines and lysines, creating a positively charged polar patch within the groove of the TPR domain. Whereas, KLC2 with the corresponding residue S328 did not interact with JIP1. Based on these finding, we propose that N343 of KLC1 can form 'a carboxylate clamp' with its neighboring asparagine to interact with JIP1, similar to that of HSP70/HSP90 organizing protein-1's (HOP1) interaction with heat shock proteins. For the binding of cargos shared by KLC1 and KLC2, we propose a different site located within the groove but not involving N343. We further propose a third binding site on KLC1 which involves a stretch of polar residues along the inter-TPR loops that may form a network of hydrogen bonds to JIP3 and JIP4. Together, these results provide structural insights into possible mechanisms of interaction between KLC TPR domains and various cargo proteins.

08 HYDROGEN↗
DOE OSTI2013

U.S. Offshore Wind Manufacturing and Supply Chain Development

The objective of the report is to provide an assessment of the domestic supply chain and manufacturing infrastructure supporting the U.S. offshore wind market. The report provides baseline information and develops a strategy for future development of the supply chain required to support projected offshore wind deployment levels.

17 WIND ENERGY↗
DOE OSTI2013

Supply Chain and Blade Manufacturing Considerations in the Global Wind Industry (Presentation)

This briefing provides an overview of supply chain developments in the global wind industry and a detailed assessment of blade manufacturing considerations for U.S. end-markets. The report discusses the international trade flows of wind power equipment, blade manufacturing and logistical costs, and qualitative issues that often influence factory location decisions. To help guide policy and research and development strategy decisions, this report offers a comprehensive perspective of both quantitative and qualitative factors that affect selected supply chain developments in the growing wind power industry.

17 WIND ENERGY↗
DOE OSTI2016

Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

This study identifies key opportunities in the carbon fiber supply chain where the United States Department of Energy's Office of Energy Efficiency and Renewable Energy resources and investments can help the United States achieve or maintain a competitive advantage. The report focuses on four application areas--wind energy, aerospace, automotive, and pressure vessels--that top the list of industries using carbon fiber and carbon fiber reinforced polymers and are also particularly relevant to EERE's mission. For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components, all contributing to a competitiveness assessment that addresses the United States' role in future industry growth. This report was prepared by researchers at Oak Ridge National Laboratory and the University of Tennessee for the Clean Energy Manufacturing Analysis Center.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Walk the Talk: How PNNL is developing a Supply Chain Security Culture

For the past decade, a team at the Pacific Northwest National Laboratory (PNNL) has engaged industry to “go beyond compliance” in controlling and securing their supply chains to ensure their goods are not diverted to nuclear weapons programs. This work has focused on dual-use industries that manufacture products that can be used in both commercial applications and in the development of a nuclear weapon. The team encourages industry to self-regulate to reduce proliferation risks. As part of that work, PNNL interviewed numerous companies about their compliance practices in order to understand their business and to build awareness around best practices to ensure security of goods and information along their supply chains. As a result, PNNL has identified seven indicators that a company can adopt as part of their commitment to nonproliferation ideals.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2014

A Framework for Evaluating R&D Impacts and Supply Chain Dynamics Early in a Product Life Cycle. Looking inside the black box of innovation

This report provides a framework for evaluation of R&D investments aimed at speeding up the pace of innovation and strengthening domestic manufacturing and supply chains, which make up a portion of the investments of the U.S. Department of Energy's (DOEs) Office of Energy Efficiency and Renewable Energy (EERE). These investments focus on early phases of the product life cycle, characterized as extending from pre-product, late stage R&D, to initial product introduction and through to early market growth. The investments aim to provide support for additional technology, supply-chain, manufacturing, and early market development to enhance or create markets for clean energy technologies and strengthen the U.S. industry base.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2017

Supply Chain Sustainability Analysis of Renewable Hydrocarbon Fuels via Indirect Liquefaction, Fast Pyrolysis, and Hydrothermal Liquefaction: Update of the 2016 State-of-Technology Cases and Design Cases

This technical memorandum describes the supply chain sustainability analyses (SCSA) for the production of three renewable hydrocarbon transportation fuels: (1) renewable high octane gasoline (HOG) via indirect liquefaction (IDL) of woody lignocellulosic biomass; (2) renewable gasoline (RG) via fast pyrolysis of woody lignocellulosic biomass; and (3) renewable diesel via hydrothermal liquefaction of algae. This technical memorandum focuses on the 2016 State of Technology (SOT) technical, economic, and environmental performance of these three fuel production pathways, as well as the 2016 SOT woody feedstock blend production and the 2016 SOT for algae feedstock production. The results of these renewable hydrocarbon fuel pathways in these SCSA analyses update those for the respective 2015 SOT cases (Cai et al., 2016; Adom et al., 2016; Frank et al., 2016), and provide an opportunity to examine the impact of technology improvements of both biomass feedstock production and biofuel production that have been achieved since the 2015 SOTs on the sustainability performance of these renewable transportation fuels. Furthermore, they reflect updates to Argonne National Laboratory’s Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model, which was released in October 2016 (ANL, 2016). The 2015 SOT case was re-evaluated using this newly-released version, which includes updates to the production of natural gas, electricity, and liquid fuels that can influence biofuels’ supply chain greenhouse gas (GHG) (CO2, CH4, and N2O) emissions. These emissions and water consumption are the two sustainability metrics assessed in this analysis. The design cases (future target projections) for these three fuel production pathways were also re-evaluated using GREET 2016. In particular, the 2016 woody blend feedstock SOT was used in lieu of the previous design case woody blend feedstock, which utilized construction and demolition waste (INL, 2014). In the 2016 woody blend feedstock SOT, the construction and demolition waste was eliminated due to a lack of Renewable Identification Number (RINs) generation, and replaced with short rotation hybrid poplar in order to align with the woody feedstock blend that was chosen by the BETO Feedstock-Conversion Interface Consortium (FCIC) for the 2017 fast pyrolysis verification.

09 BIOMASS FUELS↗
DOE OSTI2020

Critical Material Supply Chain Analysis: Magnetocalorics

Understanding manufacturing cost and supply chain implications of technologies is critical to aid adoption of next-generation energy solutions, such as advanced heating ventilation and air conditioning (HVAC) equipment for building energy efficiency. This report provides insights into the market, regulatory, technology, and cost drivers most impacting the adoption of magnetocaloric refrigeration (MCR) systems in the U.S., with a focus on the rare earth materials requirements, manufacturing costs of key components, and detail on the supply chain of critical materials.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Battery Critical Materials Supply Chain Challenges and Opportunities: Results of the 2020 Request for Information (RFI) and Workshop

The purpose of this report is to outline and discuss the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE)’s findings related to EERE’s Request for Information (RFI) on Battery Critical Materials Supply Chain Research & Development (R&D) and the EERE R&D Battery Critical Materials Supply Chain Workshop. The United States has committed to achieving 50% or more reduction of greenhouse gas pollution by 2030, with a long-term goal to completely decarbonize the U.S. economy by 2050, and to limit global warming to 1.5 degrees Celsius (The White House, 2021a).

25 ENERGY STORAGE↗
DOE OSTI2022

Initial Heliostat Supply Chain Analysis

Globally, the growing demand for concentrating solar power (CSP) technologies, primarily for electricity generation plants has been met with supply chains primarily composed of plentiful commodity materials such as steel, aluminum, and glass. Often the majority of the commodity materials are sourced within the domestic market where generating plants are constructed. Although specialty components are required for CSP solar field components - including mirror panels used for heliostat applications - these specialty components constitute about 30-50% of total system installed costs. Only a few companies and countries, including the United States, have developed the capacity to supply such specialty components. This report is an initial assessment of the global and U.S. heliostat supply chain.

14 SOLAR ENERGY↗