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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Amorphous transparent conducting oxides in context: Work function survey, trends, and facile modification

The work functions of various amorphous and crystalline transparent conducting oxides (TCO5) were measured using Kelvin probe. The films, made by pulsed laser deposition, exhibited varying work functions dependent on the composition and deposition parameters. Tin oxide showed the largest work functions of the oxides measured, while zinc oxide showed the lowest. Binary and ternary combinations of the basis TCOs showed intermediate work functions dependent on the endpoint components. Amorphous TCO5, important in OPV and other technological applications, exhibited similar work functions to their crystalline counterparts. UV/ozone treatment of TCOs temporarily increased the work function, consistent with proposed defect mechanisms associated with near-surface changes in carrier content and Fermi level. Finally, a method for facile adjustment of the work function of commercial TCOs by atomic layer deposition (ALD) capping layers was presented, illustrated by the growth of zinc oxide layers on commercial crystalline ITO films.

Yeh, T. C.↗
DOE OSTI2016

Work stealing for GPU-accelerated parallel programs in a global address space framework

Task parallelism is an attractive approach to automatically load balance the computation in a parallel system and adapt to dynamism exhibited by parallel systems. Exploiting task parallelism through work stealing has been extensively studied in shared and distributed-memory contexts. In this paper, we study the design of a system that uses work stealing for dynamic load balancing of task-parallel programs executed on hybrid distributed-memory CPU-graphics processing unit (GPU) systems in a global-address space framework. We take into account the unique nature of the accelerator model employed by GPUs, the significant performance difference between GPU and CPU execution as a function of problem size, and the distinct CPU and GPU memory domains. We consider various alternatives in designing a distributed work stealing algorithm for CPU-GPU systems, while taking into account the impact of task distribution and data movement overheads. These strategies are evaluated using microbenchmarks that capture various execution configurations as well as the state-of-the-art CCSD(T) application module from the computational chemistry domain

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Work Function Modification via Combined Charge-Based Through-Space Interaction and Surface Interaction

Work function modification of electrodes is an important factor to achieve high performance in organic electronics. However, a clear explanation of the origin of work function modification has remained elusive. Here, it is investigated how the work function of electrodes is affected by the charge-based through-space interaction with the well-known surface interaction. The studies reveal that the formation of a surface dipole leads to a work function shift, even when the work function modifying layer and substrate are separated. A work function shift is also demonstrated by electrophoretic deposition of ionic polyelectrolytes while the same polyelectrolytes do not cause any work function shift when they are spin cast. More noteworthy is that a neutral (nonionic) polymer which has no specific surface-interacting functional groups can induce work function shift of its substrate by a charge-based through-space interaction when deposited by electrospraying. These results provide a more comprehensive understanding of work function modification and motivate the design and selection of a wide range of effective work function modifying layers for organic electronics.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Working Party on International Nuclear Data Evaluation Cooperation (WPEC)

The OECD Nuclear Energy Agency (NEA) organizes cooperation between the major nuclear data evaluation projects in the world. The NEA Working Party on International Nuclear Data Evaluation Cooperation (WPEC) was established to promote the exchange of information on nuclear data evaluation, measurement, nuclear model calculation, validation, and related topics, and to provide a framework for cooperative activities between the participating projects. The working party assesses nuclear data improvement needs and addresses these needs by initiating joint activities in the framework of dedicated WPEC subgroups. Studies recently completed comprise a number of works related to nuclear data covariance and associated processing issues, as well as more specific studies related to the resonance parameter representation in the unresolved resonance region, the gamma production from fission product capture reactions, the {sup 235}U capture cross section, the EXFOR database, and the improvement of nuclear data for advanced reactor systems. Ongoing activities focus on the evaluation of {sup 239}Pu in the resonance region, scattering angular distribution in the fast energy range, and reporting/usage of experimental data for evaluation in the resolved resonance region. New activities include two subgroups on improved fission product yield evaluation methodologies and on modern nuclear database structures. Future activities under discussion include a pilot project for a Collaborative International Evaluated Library Organization (CIELO) and methods to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data. In addition to the above mentioned short-term task-oriented subgroups, WPEC also hosts a longer-term subgroup charged with reviewing and compiling the most important nuclear data requirements in a high priority request list (HPRL)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Are You Philanthropy-Ready? How to Work with Foundations on Mission-Aligned Community Solar

Community solar is emerging as a popular way to deliver a range of economic and social benefits that go beyond clean energy. The US Department of Energy (DOE) has set a goal for America to deploy enough community solar projects to power the equivalent of five million households by 2025 and create $1 billion in energy bill savings. To reach the goal, DOE has created the Community Power Accelerator, as part of the National Community Solar Partnership (NCSP). The Accelerator is an online ecosystem bringing together developers, lenders, foundations, community organizations, and other stakeholders to support the deployment of mission-aligned community solar. The Accelerator is especially focused on projects that deliver "meaningful benefits" to customers and communities, including: access by low- to moderate-income households; greater bill savings; resilience and grid benefits; community ownership; and local workforce development. Many philanthropic organizations are looking at community solar as a way to capture these benefits in their grant-making and investment programs, while also reducing pollution and promoting environmental justice. To help community-based organizations (CBOs), non-profit organizations, and mission-aligned developers seeking philanthropic support, Berkeley Lab and the National Renewable Energy Lab prepared Are You Philanthropy-Ready? How to Work with Foundations on Mission-Aligned Community Solar. The guide provides an overview of how foundations work, gives tips on what they seek in a fundable project, and provides guidance on crafting effective proposals. In short, this guide aims to help the fund-seeker become philanthropy-ready.

14 SOLAR ENERGY↗
DOE OSTI2018

The Challenge and Promise of Remote Work: A Brief Study of Remote Work and Best Practices

Due to the shift in labor market from manufacturing and construction to service-based (Statistics 2016); the commoditization of high-bandwidth communication tools; advancements in management techniques; a dearth of trained knowledge workers within a geographic region; and a growing demand for flexible scheduling options, organizations are embracing and encouraging the growing distributed workforce. These workers are actual employees, not contractors; they may work independently or as part of a team; they have direct organizational supervision; and they work in a variety of virtual arrangements. This informal field study looks at several organizations that support the remote work model from the perspective of individual employees and presents several technologies, tools, and policies that can serve to maintain company culture and otherwise close the gap between onsite and remote workers.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Toward Design Rules of Metal–Organic Frameworks for Adsorption Cooling: Effect of Topology on the Ethanol Working Capacity

Using combined experimental and computational approaches, we studied the adsorption behavior of ethanol in a series of metal-organic frameworks (MOFs) with similar building blocks but different topologies and tested their performance as adsorption coolers. Here, we analyzed the relationship between the MOF structures and their ethanol working capacities under different working conditions. Molecular-level insights into the microscopic adsorption behavior were also gained from atomistic simulations. Based on the structure-property relationships that we found, we selected another MOF (MOF-525) for study, and our experiments and simulations both showed superior ethanol working capacity for this MOF, which verified our design rules.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Hot-worked microstructure and hot workability of cold-work tool steels

Highlights: • Hot compression tests were conducted for D2 and an 8% Cr steel. • Processing maps were constructed for the evaluation of their hot workability. • They had similar hot workability concerning the flow instability. • The 8% Cr steel exhibited a larger resistance to dynamic recrystallization. - Abstract: The hot workability of two cold-work tool steels were evaluated and compared. A D2 and an advanced alloy based on 8% Cr steels (TDx) were deformed at high temperatures between 900 and 1100 °C with strain rates 0.001–10 s{sup − 1} via hot compression test. From the flow curves, processing maps were constructed based on the dynamic material model. The deformed microstructures were observed and compared in various scales with respect to the deformation conditions. Although the two alloys exhibited a large similarity in the flow instability consideration of the processing map, their behavior in microstructure evolution was different. While both alloys exhibited a tendency of strain localization in the conditions of instability, the efficiency of power dissipation in the processing maps showed an intricate correlation with the progress of dynamic recrystallization and carbide precipitation. TDx showed a distinctive behavior of carbide precipitation and a larger resistance to dynamic recrystallization, which implied a requirement on more delicate control of hot working conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Precursor Evolution and Stress Corrosion Cracking Initiation of Cold-Worked Alloy 690 in Simulated Pressurized Water Reactor Primary Water

Stress corrosion crack initiation of two thermally-treated, cold-worked (CW) alloy 690 (UNS N06690) materials was investigated in 360oC simulated PWR primary water using constant load tensile (CLT) tests and blunt notch compact tension (BNCT) tests equipped with direct current potential drop (DCPD) for in-situ detection of cracking. SCC initiation was not detected by DCPD for either the 21% or 31%CW CLT specimens loaded at their yield stress after ~9,220 hours, however intergranular (IG) precursor damage and isolated surface cracks were observed on the specimens. The two 31%CW BNCT specimens loaded at moderate stress intensity after several cyclic loading ramps showed DCPD-indicated crack initiation after 10,400 hours of exposure at constant stress intensity, which was resulted from significant growth of IG cracks. The 21%CW BNCT specimens only exhibited isolated small IG surface cracks and showed no apparent DCPD change throughout the test. Post-test cross-section examinations revealed many grain boundary (GB) nano-cavities in the bulk of all the CLT and BNCT specimens particularly for the 31%CW materials. Cavities were also found along GBs extending to the surface suggesting an important role in crack nucleation. This paper provides an overview of the evolution of GB cavities and discusses their effects on crack initiation in CW alloy 690.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2016

State of practice and emerging application of analytical techniques of nuclear forensic analysis: highlights from the 4th Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group (ITWG)

Founded in 1996 upon the initiative of the “Group of 8” governments (G8), the Nuclear Forensics International Technical Working Group (ITWG) is an ad hoc organization of official nuclear forensics practitioners (scientists, law enforcement, and regulators) that can be called upon to provide technical assistance to the global community in the event of a seizure of nuclear or radiological materials. The ITWG is supported by and is affiliated with roughly 40 countries and international partner organizations including the International Atomic Energy Agency (IAEA), EURATOM, INTERPOL, EUROPOL, and the United Nations Interregional Crime and Justice Research Institute (UNICRI). Besides providing a network of nuclear forensics laboratories that are able to assist law enforcement during a nuclear smuggling event, the ITWG is also committed to the advancement of the science of nuclear forensic analysis, largely through participation in periodic table top and Collaborative Materials Exercises (CMXs). Exercise scenarios use “real world” samples with realistic forensics investigation time constraints and reporting requirements. These exercises are designed to promote best practices in the field and test, evaluate, and improve new technical capabilities, methods and techniques in order to advance the science of nuclear forensics. The ITWG recently completed its fourth CMX in the 20 year history of the organization. This was also the largest materials exercise to date, with participating laboratories from 16 countries or organizations. Three samples of low enriched uranium were shipped to these laboratories as part of an illicit trafficking scenario, for which each laboratory was asked to conduct nuclear forensic analyses in support of a fictitious criminal investigation. An objective review of the State Of Practice and Art of international nuclear forensic analysis based upon the outcome of this most recent exercise is provided.

ITWG CMX-4↗
DOE OSTI2020

Uncovering Uranium Isotopic Heterogeneity of Fuel Pellets from the Fifth Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group

In 2017, the Nuclear Forensics International Technical Working Group (ITWG) organized their fifth 37 Collaborative Materials Exercise (CMX-5). The exercise samples were two uranium dioxide fuel pellets 38 manufactured from the same starting materials by different processes to have similar bulk isotopic 39 composition, but different spatial uranium isotopic distributions. Sets of identical materials were sent to 40 all participating laboratories, who then utilized their existing nuclear forensic capabilities to 41 independently analyse fuel pellets and identify similarities and differences of the materials’ 42 characteristics. The analytical methods used to probe the fuel pellets included ex situ, such as sectioning 43 or breaking up the pellets and analyzing dissolved pieces using inductively coupled plasma mass 44 spectrometry (ICP-MS), analyzing particles collected from intact or fragmented pellets by secondary ion 45 mass spectrometry (SIMS), as well as in situ methods, such as laser ablation coupled with ICP-MS, 46 autoradiography and nanoSIMS. In this paper we present the results of these independent analyses and 47 compare the capabilities of those nuclear forensic analytical methods to uncover details of the isotopic 48 heterogeneity of uranium fuel pellets.

Nuclear Forensic Analysis of Uranium Fuel Pellets,↗
DOE OSTI2021

Overcoming Barriers to Radiopharmaceutical Therapy (RPT): An Overview From the NRG-NCI Working Group on Dosimetry of Radiopharmaceutical Therapy

Radiopharmaceutical therapy (RPT) continues to demonstrate tremendous potential in improving the therapeutic gains in radiation therapy by specifically delivering radiation to tumors that can be well assessed in terms of dosimetry and imaging. Dosimetry in external beam radiation therapy is standard practice. This is not the case, however, in RPT. This NRG (acronym formed from the first letter of the 3 original groups: National Surgical Adjuvant Breast and Bowel Project, the Radiation Therapy Oncology Group, and the Gynecologic Oncology Group)-National Cancer Institute Working Group review describes some of the challenges to improving RPT. The main priorities for advancing the field include (1) developing and adopting best practice guidelines for incorporating patient-specific dosimetry for RPT that can be used at both large clinics with substantial resources and more modest clinics that have limited resources, (2) establishing and improving strategies for introducing new radiopharmaceuticals for clinical investigation, (3) developing approaches to address the radiophobia that is associated with the administration of radioactivity for cancer therapy, and (4) solving the financial and logistical issues of expertise and training in the developing field of RPT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Solid-liquid work of adhesion of coarse-grained models of n-hexane on graphene layers derived from the conditional reversible work method

We address the question of how reducing the number of degrees of freedom modifies the interfacial thermodynamic properties of heterogeneous solid-liquid systems. We consider the example of n-hexane interacting with multi-layer graphene which we model both with fully atomistic and coarse-grained (CG) models. The CG models are obtained by means of the conditional reversible work (CRW) method. The interfacial thermodynamics of these models is characterized by the solid-liquid work of adhesion W{sub SL} calculated by means of the dry-surface methodology through molecular dynamics simulations. We find that the CRW potentials lead to values of W{sub SL} that are larger than the atomistic ones. Clear understanding of the relationship between the structure of n-hexane in the vicinity of the surface and W{sub SL} is elucidated through a detailed study of the energy and entropy components of W{sub SL}. We highlight the crucial role played by the solid-liquid energy fluctuations. Our approach suggests that CG potentials should be designed in such a way that they preserve the range of solid-liquid interaction energies, but also their fluctuations in order to preserve the reference atomistic value of W{sub SL}. Our study thus opens perspectives into deriving CG interaction potentials that preserve the thermodynamics of solid-liquid contacts and will find application in studies that intend to address materials driven by interfaces.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗