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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Applying a polysaccharide lyase from Stenotrophomonas maltophilia to disrupt alginate exopolysaccharide produced by Pseudomonas aeruginosa clinical isolates

Pseudomonas aeruginosa is considered one of the most challenging, drug-resistant, opportunistic pathogens partly due to its ability to synthesize robust biofilms. Biofilm is a mixture of extracellular polymeric substances (EPS) that encapsulates microbial cells, leading to immune evasion, antibiotic resistance, and thus higher risk of infection. In the cystic fibrosis lung environment, P. aeruginosa undergoes a mucoid transition, defined by overproduction of the exopolysaccharide alginate. Alginate encapsulation results in bacterial resistance to antibiotics and the host immune system. Given its role in airway inflammation and chronic infection, alginate is an obvious target to improve treatment for P. aeruginosa infection. Previously, we demonstrated polysaccharide lyase Smlt1473 from Stenotrophomonas maltophilia strain k279a can catalyze the degradation of multiple polyuronides in vitro, including D-mannuronic acid (poly-ManA). Poly-ManA is a major constituent of P. aeruginosa alginate, suggesting that Smlt1473 could have potential application against multidrug-resistant P. aeruginosa and perhaps other microbes with related biofilm composition. In this study, we demonstrate that Smlt1473 can inhibit and degrade alginate from P. aeruginosa. Additionally, we show that tested P. aeruginosa strains are dominant in acetylated alginate and that all but one have similar M-to-G ratios. These results indicate that variation in enzyme efficacy among the isolates is not primarily due to differences in total EPS or alginate chemical composition. Overall, these results demonstrate Smlt1473 can inhibit and degrade P. aeruginosa alginate and suggest that other factors including rate of EPS production, alginate sequence/chain length, or non-EPS components may explain differences in enzyme efficacy.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Mutagenesis of Human Cytomegalovirus Glycoprotein L Disproportionately Disrupts gH/gL/gO over gH/gL/pUL128-131

Herein, cell-free and cell-to-cell spread of herpesviruses involves a core fusion apparatus comprised of the fusion protein glycoprotein B (gB) and the regulatory factor gH/gL. The human cytomegalovirus (HCMV) gH/gL/gO and gH/gL/pUL128-131 facilitate spread in different cell types. The gO and pUL128-131 components bind distinct receptors, but how the gH/gL portions of the complexes functionally compare is not understood. We previously characterized a panel of gL mutants by transient expression and showed that many were impaired for gH/gL-gB-dependent cell-cell fusion but were still able to form gH/gL/pUL128-131 and induce receptor interference. Here, the gL mutants were engineered into the HCMV BAC clones TB40/e-BAC4 (TB), TR, and Merlin (ME), which differ in their utilization of the two complexes for entry and spread. Several of the gL mutations disproportionately impacted gH/gL/gO-dependent entry and spread over gH/gL/pUL128-131 processes. The effects of some mutants could be explained by impaired gH/gL/gO assembly, but other mutants impacted gH/gL/gO function. Soluble gH/gL/gO containing the L201 mutant failed to block HCMV infection despite unimpaired binding to PDGFRα, indicating the existence of other important gH/gL/gO receptors. Another mutant (L139) enhanced the gH/gL/gO-dependent cell-free spread of TR, suggesting a “hyperactive” gH/gL/gO. Recently published crystallography and cryo-electron microscopy studies suggest structural conservation of the gH/gL underlying gH/gL/gO and gH/gL/pUL128-131. However, our data suggest important differences in the gH/gL of the two complexes and support a model in which gH/gL/gO can provide an activation signal for gB.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Taking the Air Out of Respiratory Pandemics: An R&D Effort for Developing New, Far Less Disruptive and Frightening Protective Measures to Extinguish Airborne Pathogen Outbreaks

This short concept article discusses four specific ways to eradicate respiratory pandemics once and for all. These include: Protecting the nose, mouth, throat and lungs; New hygiene regimens; Clearing the air; and Biophysical interventions. Technical breakthoughs in all four of these areas would not only protect people from life-threatening pathogens, but also take the dread out of respiratory disease outbreaks.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Housing Stability Index: Measuring the risk of housing disruption during the COVID-19 pandemic

The Housing Stability Index (HSI) quantifies the decreased stability of housing (renter or owner occupied) across the United States due to missed or deferred housing payments (rent or mortgage payments) or serious delinquency. This is done through calculating the ratio of the near real-time percentage of occupied housing units not at risk of eviction or foreclosure to the baseline percentage of occupied housing units not at risk by county. For purposes of this index, “at risk” indicates a higher percentage of residents unable to make rent or mortgage payments. An HSI value of 1 indicates no additional housing instability (above housing instability before the start of the COVID-19 pandemic) due to COVID-19 while declining values indicate increasing housing instability. Argonne also created two sub-indices, Owner-Occupied Housing Units at Risk and Renter Occupied Housing Units at Risk, to differentiate risk between homeowners and renters.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Implementation of Disruptive Designs for Gas Turbine Components Utilizing Additive Manufacturing

Electron beam melting (EBM) is an additive manufacturing process used to print metallic components with complex geometries for aerospace applications. A preheating characteristic enables this technology to avoid large accumulation of residual stress during printing. However, cracking mechanisms particularly in Ni-based superalloys are associated with not only residual stress but also with microstructure (i.e., solidification morphology, transient evolution of γ'). Siemens is committed to AM technology for gas turbine applications. The ability to novel predictive designs of turbine blades would reduce process development time and allow acquisition of key microstructure and performance data early in a design campaign. Siemens initiated a project to establish the design rules for the fabrication of non-printable Nibased superalloys. This phase 1 program demonstrates the feasibility for virtual fabrication of the actual blade geometries through EBM process.

42 ENGINEERING↗
DOE OSTI2021

A laser inverse Compton scattering diagnostic to study runaway electron dynamics during tokamak disruptions

Both technical and simulation progress has been made toward implementing a laser inverse Compton scattering diagnostic on the DIII-D tokamak. This is a novel diagnostic which uses a short (sub-ns) pulse laser together with a fast (sub-ns) gated x-ray detector to measure relativistic electrons inside a tokamak plasma. The study of these relativistic electrons is important to make sure they can be removed from any tokamak-based power reactor, as they could damage vessel walls and cooling lines. This diagnostic is completely new for magnetic fusion research and has never been implemented before on a tokamak. It is found that good signals and radial profiles could be obtained with an optimized high-energy (7 Joule) laser. Using a standard off-the-shelf Nd:YAG (0.7 Joule) laser would give some signals above the noise but no ability to measure the relativistic electron radial profile.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

RePOWERD: Restoration of Power Outage from Wide-area Severe Weather Disruptions

The purpose of the RePOWERD project is to develop a probabilistic and a simulation based power restoration forecasting model for tropical storms based on geographic utility service areas, impacts to energy infrastructures and transportation networks, time-varying customer outage number, crew information (i.e., crew size, crew staging requirements), and utility restoration plans. Energy infrastructure is a critical lifeline essential for the United States’ national and economic security. Like other critical infrastructures, this infrastructure is aging and is at a high risk of damages from extreme weather events. Based on the number of reported outages in EAGLE-I during 2020 and 2021, it is evident that the current energy infrastructure is not equipped to handle extreme event impacts and will contribute to significant outages. From a resilience perspective, it is essential to forecast restoration time in the event of a severe weather induced power outage to assist the US Department of Energy, emergency managers, and first responders with resource planning. This project contributes to this crucial need. This report details the models, that were developed in this pilot study, to determine the rate of restoration and estimated time of restoration (ETR) during tropical storm events within counties and utility service areas based on damage to energy infrastructures and total number of customers experiencing outages.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Territorial Economic Impact Index: Measuring the ongoing effects of long-term disruptions to Pacific Island Territories

The Territorial Economic Impact Index (TEII) estimates the change in overall territory-level economic activity during the COVID-19 pandemic relative to January 2020. It shows which Pacific Island Territories may be more susceptible to large reductions in economic activity compared to normal conditions by looking at which industries make up each territory’s economy and then tracking monthly changes in industry employment at the U.S. national level. Economic activity in the TEII is measured by the total value added of all industries within the territory. Territories with economic activities dominated by industries experiencing rising unemployment can expect larger direct impacts to their local economies, particularly if the industries account for a large portion of the economic output of that county. Results are available for all three Pacific Island Territories: American Samoa, Guam, and the Commonwealth of the Northern Mariana Islands.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2023

Coherent Wavelength Switched Co-Packaged Optics to Disrupt Datacenters/HPC (AKA "QRock") (Final Report)

This project resulted in multiple first-of-a-kind demonstrations, including two generations of transmitters, a receiver, and a complete coherent link. The transmitter architecture, based on EAMs to generate QPSK modulation was first demonstrated in InP, which has limitations for scaling up to chips with multiple channels for full WDM architectures, and implementing the densities and level of integration needed to implement co-packaging with electronics. Our work resulted in the first demonstration of this architecture on a Si platform compatible with copackaging, and our working prototypes illustrated the potential of the approach. The link demonstration was also the first coherent optical link realized in a multi-micron waveguide platform. For the transmitters, integrating efficient III-V EAM devices into the large waveguide Si platform simultaneously enables significant reduction in driver power consumption while minimizing optical losses in routing and fiber coupling. On the receiver side, optical coupling and propagation losses are also minimized in the multi-micron platform, reducing required laser optical power which improves link energy efficiency. The measurement results presented in the final report demonstrate that we achieved the speed objectives for the program (112Gb/s: 56Gbaud QPSK), albeit at a higher BER than targeted. The report provides assessments of the low-powercoherent link architecture and associated components developed under the program from both technological and commercial viewpoints.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Disruptive Technology for Carbon Negative Commodity Chemicals

This project was designed to develop an economically attractive process for the carbon negative production of the commodity biochemical succinic acid. To compete against petroleum derived biochemicals, the process must deliver high raw material conversion efficiency and high volumetric productivity to reduce both recurring and capital-related costs, respectively. The proposed process introduces additional electrons sourced from hydrogen into the biosynthetic pathway so that the carbon from two CO2 molecules can be combined with each glucose to significantly increase succinic acid yields. The process also uses ultrafiltration to continuously remove the product from the bioreactor to avoid product inhibition and extend the productive life of the cell extract. Genetic deletions and specific enzyme removal during extract preparation more efficiently direct both atomic and electronic resources toward product formation. A preliminary technoeconomic analysis indicates that these process innovations made possible by cell-free production will enable large scale production with attractive ROI and profitability. This two-year project provided some 29 distinct insights, analytical advances, and process improvements that resulted in a demonstration of process feasibility. However, an estimated two to three years of additional development will be required to achieve convincing pilot scale demonstrations that will motivate large scale investments.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Two-stage Stochastic Generalized Disjunctive Programming (GDP) Model for Proactive Planning and Reactive Operations of Resilient Power Systems under Disruptions

In this work, we propose a Generalized Disjunctive Programming (GDP) model that optimizes both long-term capacity planning (such as the number and size of dispatchable/renewable generators, batteries, and transmission lines) and hourly operation (such as on/off schedules of dispatchable generators, power output from each generator, and power flow) to maximize power system reliability while minimizing total cost and CO2 emissions.

Cho, Seolhee↗