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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 1,441 records · Page 80
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

High-throughput screening of the ReFRAME, Pandemic Box, and COVID Box drug repurposing libraries against SARS-CoV-2 nsp15 endoribonuclease to identify small-molecule inhibitors of viral activity

SARS-CoV-2 has caused a global pandemic, and has taken over 1.7 million lives as of mid-December, 2020. Although great progress has been made in the development of effective countermeasures, with several pharmaceutical companies approved or poised to deliver vaccines to market, there is still an unmet need of essential antiviral drugs with therapeutic impact for the treatment of moderate-to-severe COVID-19. Towards this goal, a high-throughput assay was used to screen SARS-CoV-2 nsp15 uracil-dependent endonuclease (endoU) function against 13 thousand compounds from drug and lead repurposing compound libraries. While over 80% of initial hit compounds were pan-assay inhibitory compounds, three hits were confirmed as nsp15 endoU inhibitors in the 1–20 μM range in vitro. Furthermore, Exebryl-1, a ß-amyloid anti-aggregation molecule for Alzheimer’s therapy, was shown to have antiviral activity between 10 to 66 μM, in Vero 76, Caco-2, and Calu-3 cells. Although the inhibitory concentrations determined for Exebryl-1 exceed those recommended for therapeutic intervention, our findings show great promise for further optimization of Exebryl-1 as an nsp15 endoU inhibitor and as a SARS-CoV-2 antiviral.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Identifying key determinants and dynamics of SARS-CoV-2/ACE2 tight interaction

SARS-CoV-2 virus, the causative agent of Covid-19, has fired up a global pandemic. The virus interacts with the human receptor angiotensin-converting enzyme 2 (ACE2) for an invasion via receptor binding domain (RBD) on its spike protein. To provide a deeper understanding of this interaction, we performed microsecond simulations of the RBD-ACE2 complex for SARS-CoV-2 and compared it with the closely related SARS-CoV discovered in 2003. We show residues in the RBD of SARS-CoV-2 that were mutated from SARS-CoV, collectively help make the RBD anchor much stronger to the N-terminal part of ACE2 than the corresponding residues on RBD of SARS-CoV. This would result in a reduced dissociation rate of SARS-CoV-2 from human receptor protein compared to SARS-CoV. The phenomenon was consistently observed in simulations beyond 500 ns and was reproducible across different force fields. Altogether, our study adds more insight into the critical dynamics of the key residues at the virus spike and human receptor binding interface and potentially aids the development of diagnostics and therapeutics to combat the pandemic efficiently.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Fluorescent Crimean-Congo hemorrhagic fever virus illuminates tissue tropism patterns and identifies early mononuclear phagocytic cell targets in Ifnar -/- mice

Crimean-Congo hemorrhagic fever virus (CCHFV, order Bunyavirales, family Nairoviridae, genus Orthonairovirus) is the tick-borne etiological agent of Crimean-Congo hemorrhagic fever (CCHF) in humans. Animals are generally susceptible to CCHFV infection but refractory to disease. Small animal models are limited to interferon-deficient mice, that develop acute fatal disease following infection. Here, using a ZsGreen1- (ZsG) expressing reporter virus (CCHFV/ZsG), we examine tissue tropism and dissemination of virus in interferon-α/β receptor knock-out (Ifnar -/- ) mice. We demonstrate that CCHFV/ZsG retains in vivo pathogenicity comparable to wild-type virus. Interestingly, despite high levels of viral RNA in all organs assessed, 2 distribution patterns of infection were observed by both fluorescence and immunohistochemistry (IHC), corresponding to the permissiveness of organ tissues. To further investigate viral dissemination and to temporally define cellular targets of CCHFV in vivo, mice were serially euthanized at different stages of disease. Flow cytometry was used to characterize CCHFV-associated alterations in hematopoietic cell populations and to classify infected cells in the blood, lymph node, spleen, and liver. ZsG signal indicated that mononuclear phagocytic cells in the lymphatic tissues were early targets of infection; in latestage infection, overall, the highest levels of signal were detected in the liver, and ZsG was found in both antigen-presenting and lymphocyte cell populations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Improved Calculation of the Young’s Modulus of Rectangular Prisms from Their Resonant Frequency Overtones by Identifying Appropriate Shear Constants

Young’s modulus is an important parameter for characterizing the strength of, and wave propagation through, a given material. This study improves the estimation of Young’s modulus using the impulse excitation technique based on an experimental analysis of 19 borosilicate glass bars. Analysis of the frequency equations relating Young’s modulus to the out-of-plane and in-plane flexural resonant frequencies of rectangular prisms has been conducted for both the fundamental frequency and its overtones at higher orders of vibration. Furthermore, the Young’s moduli of three novaculite rocks with various porosities were then measured up to the seventh order of vibration to validate the optimum shear constant equation for estimating Young’s modulus. Young’s modulus was found to be nearly frequency independent for these rock samples.

Impulse excitation↗
DOE OSTI2019

Path-seq identifies an essential mycolate remodeling program for mycobacterial host adaptation

The success of Mycobacterium tuberculosis (MTB) stems from its ability to remain hidden from the immune system within macrophages. Here, we report a new technology (Path-seq) to sequence miniscule amounts of MTB transcripts within up to million-fold excess host RNA. Using Path-seq and regulatory network analyses, we have discovered a novel transcriptional program for in vivo mycobacterial cell wall remodeling when the pathogen infects alveolar macrophages in mice. We have discovered that MadR transcriptionally modulates two mycolic acid desaturases desA1/desA2 to initially promote cell wall remodeling upon in vitro macrophage infection and, subsequently, reduces mycolate biosynthesis upon entering dormancy. We demonstrate that disrupting MadR program is lethal to diverse mycobacteria making this evolutionarily conserved regulator a prime antitubercular target for both early and late stages of infection

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Towards a study protocol: A data-driven workflow to identify error sources in direct ink write mechatronics

Abstract Using Direct Ink Write (DIW) technology in a rapid and large-scale production requires reliable quality control for printed parts. Data streams generated during printing, such as print mechatronics, are massive and diverse which impedes extracting insights. In our study protocol approach, we developed a data-driven workflow to understand the behavior of sensor-measured X- and Y- axes positional errors with process parameters, such as print velocity and velocity control. We uncovered patterns showing that instantaneous changes in the velocity, when the build platform accelerates and decelerates, largely influence the positional errors, especially in the X- axis due to the hardware architecture. Since DIW systems share similar mechatronic inputs and outputs, our study protocol approach is broadly applicable and scalable across multiple systems. Graphical abstract

36 MATERIALS SCIENCE↗
DOE OSTI2019

Identifying Muon Neutrino Charged-Current Interactions in the MicroBooNE Detector

The MicroBooNE experiment is a short-baseline neutrino experiment at the Fermi National Accelerator Laboratory (FNAL) in the US, receiving a highly pure muon neutrino beam from the Booster Neutrino Beam (BNB) and taking data since October 2015. The main physics goal of MicroBooNE is to clarify the nature of the low-energy excess of electron-like events observed by the MiniBooNE Cherenkov detector, which due to its detector technology is unable to resolve whether the observed excess shower-like events are due to electrons or photons. Instead, MicrooBooNE employs cutting-edge liquid argon time projection chamber (LArTPC) technology, which offers excellent spatial and calorimetric resolution, which makes it possible to reconstruct complex neutrino interactions and to efficiently distinguish different final state particle types. This thesis presents a fully-automated event selection of interactions of the types ν μ +Ar → μ - + X and ν μ + Ar → μ - + p + X developed using the Pandora multi-algorithm approach to pattern recognition for LArTPC experiments. The analysis in this work is performed on a subset of the MicroBooNE Run 1 dataset corresponding to 4.52 × 10 19 protons on target acquired by the MicroBooNE detector between February and October 2016. The analysis quantifies the main signal and background interaction channels that produce a reconstructed neutrino interaction with one and two particles in the final state, and quantifies the extent to which different aspects of the Pandora reconstruction affect the selection performance. MicroBooNE is a surface detector, and therefore cosmic-ray tracks are the main observed background. A direction fitting procedure has been implemented in this analysis to formulate directional probabilities, using the Bethe equation and the high-resolution calorimetric information of MicroBooNE, to reduce this cosmic-ray background. This functionality is used to enhance the efficiency of the Pandora cosmic ray tagging logic, and the impact of this procedure on the reconstruction and event selection performance is analysed. The result of this study is two fully-automated selections of ν μ +Ar → μ - + X (57.91% pure) and ν μ + Ar → μ - + p + X (78.30% pure) with efficiencies of 64.35% and 62.65%, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Factorial experiment to identify two-way interactions between temperature, harvesting period, hydraulic retention time, and light intensity that influence the biomass productivity and phosphorus removal efficiency of a microalgae–bacteria biofilm

Rotating algae biofilm reactors (RABRs) can reduce energy requirements for wastewater reclamation but require further optimization for implementation at water resource recovery facilities (WRRF). Optimizing RABR operation is challenging because conditions at WRRF change frequently, and disregarding interaction terms related to these changes can produce incorrect conclusions about RABR behavior. This study evaluated the two-way interaction and main effects of four factors on the biomass productivity and phosphorus removal efficiency of a microalgae-bacteria biofilm grown in municipal anaerobic digester centrate, with factor levels and operating conditions selected to mimic a pilot RABR at a WRRF in Utah. Two-way interactions harvesting period*light intensity (LI), harvesting period*temperature, and LI*hydraulic retention time (HRT) had significant effects on biomass productivity: at high temperature and low LI, highest biomass productivity was achieved with a 14-day harvesting period, but at medium temperature and high LI, highest biomass productivity was achieved with a 7-day harvesting period. At high HRT, highest biomass productivity occurred at low LI, but at low HRT, highest biomass productivity occurred at high LI. Phosphorus removal was strongly influenced by LI and occurred most rapidly during the first 2 days HRT, which suggests precipitation contributed significantly to phosphorus removal. These observations provide insight for further RABR optimization.

09 BIOMASS FUELS↗
DOE OSTI2016

Identifying Isotropic Events using an Improved Regional Moment Tensor Inversion Technique

Research was carried out investigating the feasibility of using a regional distance seismic waveform moment tensor inverse procedure to estimate source parameters of nuclear explosions and to use the source inversion results to develop a source-type discrimination capability. The results of the research indicate that it is possible to robustly determine the seismic moment tensor of nuclear explosions, and when compared to natural seismicity in the context of the a Hudson et al. (1989) source-type diagram they are found to separate from populations of earthquakes and underground cavity collapse seismic sources.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2017

Issues Identified During September 2016 IBM OpenMP 4.5 Hackathon

In September, 2016 IBM hosted an OpenMP 4.5 Hackathon at the TJ Watson Research Center. Teams from LLNL, ORNL, SNL, LANL, and LBNL attended the event. As with the 2015 hackathon, IBM produced an extremely useful and successful event with unmatched support from compiler team, applications staff, and facilities. Approximately 24 IBM staff supported 4-day hackathon and spent significant time 4-6 weeks out to prepare environment and become familiar with apps. This hackathon was also the first event to feature LLVM & XL C/C++ and Fortran compilers. This report records many of the issues encountered by the LLNL teams during the hackathon.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

Annual Report, Fall 2016: Identifying Cost Effective Tank Waste Characterization Approaches

This report documents the activities that were performed during the second year of a project undertaken to improve the cost effectiveness and timeliness of SRNL’s tank closure characterization practices. The activities performed during the first year of the project were previously reported in SRNL-STI-2015-00144. The scope of the second year activities was divided into the following three primary tasks: 1) develop a technical basis and strategy for improving the cost effectiveness and schedule of SRNL’s tank closure characterization program; 2) initiate the design and assembly of a new waste removal system for improving the throughput and reducing the personnel dose associated with extraction chromatography radiochemical separations; and 3) develop and perform feasibility testing of three alternative radiochemical separation protocols holding promise for improving high resource demand/time consuming tank closure sample analysis methods.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Development of Geomechanical Screening Tools to Identify Risk: An Experimental and Modeling Approach for Secure CO 2 Storage Final Technical Report

CO 2 injection in the subsurface introduces additional complexity in terms of interactions of the reservoir host pore fluid with natural heterogeneity of hydro-mechanical properties of the rock. Natural heterogeneity of the reservoir rock and caprock formations includes spatial variation of hydro-mechanical properties as well as the presence of natural fractures. We developed a coupled mathematical modeling and experimental framework that takes into account the effect of rock heterogeneity on effective mechanical properties of the rock in contact with CO 2 . We performed accurate laboratory experiments to determine the changes in rock mechanical properties due to mineral dissolution in the presence of carbonic acid generated by CO 2 injection. A two-scale adaptive homogenization framework was then developed to consistently upscale petrophysical and geomechanical properties to the field scale. Further, we also developed high-fidelity, numerical solution schemes, non-linear and linear solvers and preconditioners to solve the coupled flow, reactive transport and geomechanical system. The numerical model was then used to study field scale CO 2 sequestration problems for the two selected field sites: (1) Frio formation and (2) Cranfield site. We also developed robust schemes for field data assimilation, model calibration such that the residual uncertainty at the end of the data assimilation procedures can be faithfully represented while taking into account the coupled geochemical and geomechanical processes.

42 ENGINEERING↗
DOE OSTI2018

A safety and licensing roadmap to identify the research and development gaps of commercial molten salt reactors

Molten salt reactors (MSRs) both inherently and through good design possess highly desirable safety attributes. Successful commercial deployment of MSRs is heavily dependent on establishing their safety characteristics in a well-coordinated licensing requirements program. The approach outlined is based on adapting the MSR licensing process to the current LWR–based NRC process that exists today, which has been the traditional approach used by new technologies such as the Pebble Bed Reactor licensing application, the Clinch River Breeder Reactor licensing application, and more recently the NuScale licensing application. NRC has recognized some of the unique passively safe aspects of advanced non-LWR reactors and has introduced an advanced reactor strategic plan which will address policy issues that need to be addressed to accommodate advanced reactor concepts within the existing regulatory framework. Examples of some of these policy issues are the use of functional containment, the use of mechanistic source terms, and more reliance on performance-based and risk-informed regulatory processes, such as the Licensing Modernization Project, which emphasizes the use of risk-informed processes to select licensing basis events, safety categorization of SSC, and well-defined defense-in-depth systems. Applying performance-based, risk-informed regulatory processes is, consequently, vital to substantially decreasing the cost, time, and uncertainty of commercial MSR reactor licensing while providing for the health and safety of the public and protecting the environment. This document is intended to provide a roadmap for the MSR licensing and safety activities necessary to provide a success path to commercialization.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2018

Low-GWP Refrigerant Evaluation in AC Systems for High Ambient Temperature Applications - Design and Simulation Practice to Identify Charge Reduction Opportunities for Residential AC/HP Units

Based on three 5-ton, single-speed heat pumps (HPs), using R-410A, which use the same compressor, indoor blower and outdoor fan, the DOE/ORNL Heat Pump Design Model was used to conduct comparative modelling study. Regarding charge reduction opportunities, in general, we recommend: 1. Downsizing the outdoor condenser will reduce the required system charge, i.e. using smaller tube diameters or fewer tubes; reducing the evaporator inner volume is less important; to offset the reduced condenser tube side surface area, one can increase the air side surface area (fin density) or condenser air flow rate via using a more efficient fan. 2. microchannel heat exchangers are most effective in reducing the required charge, by up to 60% in the condenser and evaporator. To develop low charge systems, one should at least use a microchannel heat exchanger as the outdoor condenser. 3. TXV systems are less sensitive to charge reduction. For the drop-in application, one can decrease the charge to minimize the liquid section in the condenser, at the expense of minor performance degradation; for example, when reducing the system charge by 15% (decrease the subcooling degree to 2R), the simulation results prove that the decrease is less than 3% in the EER and less than 6% in the capacity.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

In-situ method development to identify radiological contamination in soils

Currently, when sampling soils for radiological contamination, technicians dig holes, remove samples, transport the samples to a laboratory, analyze the samples in the laboratory, and then return the sample to the site or dispose of the sample. Rapid in-situ analysis could eliminate the need for 90% of laboratory analyses, reduce waste, and decrease cost. Increasing the number of sites analyzed per dollar spent would allow for more precisely defined contamination areas. This work builds on a method developed for the Savannah River Nuclear Solutions’ Environmental Compliance group to determine 137 Cs in fauna and technology developed for DOE’s Office of Nuclear Incident Response. The 137 Cs method previously developed is as accurate as the laboratory measurements and provides results in minimal time. We extended this method to other media (soils) and were able to report possible contamination levels within the measured volume.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗