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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Repair strategy for fused silica wedged focus lens with high-density filamentary damage

The National Ignition Facility (NIF) is intentionally operated with the final fused silica glass (SiO2) optics exposed to fluences and intensities with the potential to induce damage that will grow with additional laser exposure. Therefore, the NIF operates a recycle loop to refurbish final optics by mitigating any initiated surface damage to arrest its growth. However, the morphology of filamentary damage, caused by local self-focusing in the bulk of a silica optic, adds complexity to optics mitigation and provides a limitation to optic reusability. Here, we evaluate techniques for mitigating isolated and clustered filamentary damage. Optical microscopy before and after installation on NIF was used to determine the efficacy of filamentary mitigation after a series of high fluence and intensity laser exposures. The challenges and success rate of the methods are compared for various filamentary damage mitigation strategies.

National Ignition Facility↗
DOE OSTI2025

Discovery of an autoinhibited conformation in mesotrypsin reveals a strategy for selective serine protease inhibition

Selective inhibition of the more than 100 S1 family serine proteases is a long-standing challenge due to their active site similarity. Mesotrypsin, implicated in cancer progression, exemplifies these difficulties; no current inhibitors achieve selectivity over other human trypsins. We found an unexpected autoinhibited conformation of mesotrypsin via x-ray crystallography, revealing a cryptic pocket adjacent to the active site. Using high-throughput virtual screening targeting this cryptic pocket, we identified a conformationally selective small-molecule inhibitor that stabilizes the inactive state of mesotrypsin. This inhibitor demonstrates selectivity for mesotrypsin over other trypsins. Our findings challenge the accepted view of digestive trypsins as constitutively active enzymes lacking potential for allosteric regulation. Furthermore, analyses of other structures suggest that dynamic sampling of closed states with analogous allosteric cryptic pockets appears widespread among S1 serine proteases. These observations point to a potentially generalizable strategy to achieve selective inhibition, offering broad implications for drug development targeting serine proteases in cancer and other diseases.

Coban, Matt↗
DOE OSTI2024

Time-resolved multi-omics reveals diverse metabolic strategies of Salmonella during diet-induced inflammation

With a rise in antibiotic resistance and chronic infection, the metabolic response of Salmonella enterica serovar Typhimurium to various dietary conditions over time remains an understudied avenue for novel, targeted therapeutics. Elucidating how enteric pathogens respond to dietary variation not only helps us decipher the metabolic strategies leveraged for expansion but also assists in proposing targets for therapeutic interventions. In this study, we use a multi-omics approach to identify the metabolic response of Salmonella enterica serovar Typhimurium in mice on both a fibrous diet and high-fat diet over time. When comparing Salmonella gene expression between diets, we found a preferential use of respiratory electron acceptors consistent with increased inflammation in high-fat diet mice. Looking at the high-fat diet over the course of infection, we noticed heterogeneity in samples based on Salmonella ribosomal activity, which is separated into three infection phases: early, peak, and late. We identified key respiratory, carbon, and pathogenesis gene expressions descriptive of each phase. Surprisingly, we identified genes associated with host cell entry expressed throughout infection, suggesting subpopulations of Salmonella or stress-induced dysregulation. Collectively, these results highlight not only the sensitivity of Salmonella to its environment but also identify phase-specific genes that may be used as therapeutic targets to reduce infection.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

An Acid-Free, Temperature-Based Cation Contamination Removal Strategy for PEM Water Electrolysis

It is widely understood that the durability and reliability of polymer electrolyte membrane (PEM) water electrolyzers are heavily dependent on feedwater purity, with cation contaminants that originate from incomplete water purification and balance of plant materials significantly harming electrolyzer performance. However, contamination remains a challenge and a common cause of failure at the stack level, indicating the need for strategies to recover the performance of contaminated cells. In this study, we investigate the effects of temperature on the uptake, electrochemical impacts, and removal of contaminant calcium and iron cations. Lower operating temperatures increase the sensitivity of the cell performance to contaminant cations, while also decreasing cation uptake and promoting contaminant removal. Computational charge transfer modelling shows that lower temperature increases the concentration of contaminant at the cathode and facilitates their removal from the cell. By testing single cells under scenarios designed to mimic stack temperature dynamics, we investigate low-temperature operation as an approach to stack-relevant contaminant recovery. Together, these results demonstrate that the low-temperature recovery approach is a promising approach for acid-free contamination recovery for PEM water electrolysis to promote stack reliability and durability.

08 HYDROGEN↗
DOE OSTI2025

Compatibilization Strategy and Mechanism for Co-stabilizing Commingled Plastics and Pyrolyzed Rubber in Asphalt

Hot mix asphalt mixture is considered the ideal approach to reuse waste plastics in high-value applications because of its very high amount of usage in highway construction. However, the differences in polarity and density between polymers and asphalt lead to polymer coalescence and therefore the poor storage stability of modified asphalt. These challenges are exalted when recycling commingled plastics. This study introduced an innovative compatibilization strategy and mechanism for co-stabilizing commingled plastics and pyrolyzed rubber in asphalt. Commingled plastics were first grafted with maleic anhydride for surface activation, followed by reactive kneading with pyrolyzed rubber and crosslinking agent to form an integrated thermoplastic elastomer (ITPE) for asphalt modification. The mechanical, thermal, and interfacial behaviors of the ITPE were evaluated through tensile testing, thermogravimetric analysis, and scanning electron microscopy. The storage stability and rheological properties of the modified binder blends were evaluated through the cigar tube test and dynamic shear rheometer testing. Results demonstrated a successful formation of imide bonds in the ITPE, which can improve the strength, ductility, and thermal stability of rubber–plastic composites. Appropriate utilization of crosslinking agents can improve both rutting and fatigue resistance of ITPE-modified asphalt with good storage stability because of the co-existence of rigid plastic and soft rubbery regimes and the formation of a crosslink network. Furthermore, excessive content of crosslinker led to severe phase separation and reduced storage stability of modified binder blends. Extra crosslinker tended to float in asphalt because of its low density and caused an excessive formation of the crosslink network in the top section of the asphalt.

asphalt binder modifiers↗
DOE OSTI2026

Off-gas capture: a promising strategy for removal and recovery of toxic bioproducts in aerobic fermentation

In many bioprocesses, maximum achievable titers are limited below economically viable levels by toxic accumulation of the primary end-product. To combat end-product inhibition, a variety of in situ product removal technologies have been developed to selectively remove or partition toxic bioproducts, thereby prolonging fermentation and improving overall process efficiency. Use of an in situ organic overlay to partition toxic hydrophobic products is a commonly employed approach, but this technique occupies valuable space in the fermentor, imposes replacement costs for unrecovered solvent, and increases downstream separation due to formation of stable emulsions. In addition, for many volatile hydrophobic products produced under aerobic conditions—including medium-chain alcohols, esters, monoterpenes, and other aviation fuel precursors—a significant fraction of the product is volatilized to the fermentor off-gas and must be recovered separately to maximize product yield. To address these challenges, we explore the viability of leveraging existing aeration energy to fully strip and recover volatile products from the fermentor off-gas. We compare two strategies of in situ product removal—liquid–liquid extraction and direct recovery from fermentation off-gas—for the production and recovery of intermediates used to generate isoprene and DMCO (1,4-dimethylcyclooctane), a high-performance jet fuel. We evaluate product toxicity, solvent toxicity, solvent partitioning, and the impact of aeration and internal overlay configurations on product volatilization rates. We then optimize product recovery from fermentor off-gas via condensation in chilled solvent, achieving 84% capture efficiency. In addition to greatly simplifying downstream processing, relying on aeration for product volatilization in the absence of an internal overlay enables continuous removal of toxic fermentation products up to maximum isoprenol titers of 20.4 g/L, the highest reported to date.

isoprene↗
DOE OSTI2026

Data for "Examining Organic Acid Production Potential and Growth-Coupled Strategies in Issatchenkia orientalis Using Constraint-Based Modeling"

Growth-coupling product formation can facilitate strain stability by aligning industrial objectives with biological fitness. Organic acids make up many building block chemicals that can be produced from sugars obtainable from renewable biomass. Issatchenkia orientalis is a yeast strain tolerant to acidic conditions and is thus a promising host for industrial production of organic acids. Here, we use constraint-based methods to assess the potential of computationally designing growth-coupled production strains for I. orientalis that produce 22 different organic acids under aerobic or microaerobic conditions. We explore native and engineered pathways using glucose or xylose as the carbon substrates as proxy constituents of hydrolyzed biomass. We identified growth-coupled production strategies for 37 of the substrate-product pairs, with 15 pairs achieving production for any growth rate. We systematically assess the strain design solutions and categorize the underlying principles involved.

Bioproducts↗
DOE OSTI2025

Data Repository for Multi-Objective Urban Observational Strategies: A risk-based framework for expanding flood sensor networks.

These data support the manuscript "Multi-Objective Urban Observational Strategies: A risk-based framework for expanding flood sensor networks." These data are generated to allow water managers to reason about optimal locations to expand a flood observation system from multiple perspectives, specifically focusing on flood hazards, and population exposure to flooding. The data included are a) a shapefile of individual sensor locations b) a shapefile of river reach catchments, c) raster of FEMA flood likelihood layers d) shapefile of population locations and population socioeconomic characteristics. The code is written in R and includes all files necessary to generate the figures for the associated manuscript. Interactive maps of the final calculated maps of hazard, vulnerability, exposure, and risk are also included as html files.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Analysis strategy for ultrafast X-ray photon correlation spectroscopy

We explain an analysis strategy for ultrafast X-ray photon correlation spectroscopy, a technique enabled by X-ray free electron lasers to probe nano- and atomic-scale dynamics in complex systems on nanosecond timescales or faster. Central to the technique is the methodology for extracting contrast in coherent X-ray diffraction patterns, known as speckle patterns. Guided by simulations, we analyze common challenges and examine errors encountered in contrast extraction. A method for accurately determining contrast amid shot noise across a wide range of count rates is presented.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Space charge dominated momentum spread and compensation strategies in the post-linac section of Proton Improvement Plan-II at Fermilab

The upcoming Proton Improvement Plan-II (PIP-II), designated for enhancements to the Fermilab accelerator complex, features a new 800 MeV superconducting linac and a Beam Transfer Line (BTL) to transport the beam to the existing Booster synchrotron. To mitigate the space charge tune shift associated with a high intensity accumulated beam, the low emittance linac beam is used to paint the ring phase space both transversely and longitudinally. To prevent losses caused by particles injected outside the rf separatrix while painting longitudinal phase space, the momentum spread of the incoming beam should not exceed 2.1 x 10^-4. Detailed simulations showed that due to space charge, the rms momentum spread increases to 4 x 10^-4 while it is transported in the BTL --about twice the allowable limit. In this paper, we outline a mitigation strategy involving a debuncher cavity. We discuss location, operating frequency, and gap voltage under both nominal and perturbed beam conditions, specifically accounting for momentum jitter. The impact of cavity misalignments is also assessed. The paper concludes by recommending an optimized configuration.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Ion Trapping Studies and Mitigation Strategies for the EIC ERL-Based Strong Hadron Cooler

An Energy Recovery Linac based strong hadron cooler was previously considered for the Electron-Ion Collider. The required electron beam parameters for variable-energy strong hadron cooling place significant constraints on ion trapping and collective effects. This paper presents initial studies of these constraints through a combination of analytical modelling and numerical simulations of ion production, trapping behaviour, and mitigation strategies. A multi-bunch tracking framework based on ELEGANT with the ionEffects module is used to simulate machine operation over millisecond time scales, corresponding to more than 3 × 10^5 electron bunches. The simulations include modelling of ionisation processes together with transverse electron–ion dynamics, allowing the evolution and accumulation of ions to be investigated. Analytical expressions based on Gaussian beam distributions are used to estimate ion trapping conditions and benchmark the simulation results. A bi-periodic bunch spacing scheme is also investigated as a possible mitigation method by detuning the ion oscillation frequency. These studies provide an initial assessment of ion trapping in the strong hadron cooler and demonstrate possible approaches for reducing beam–ion effects.

Bi, R. [Lancaster University, Cockcroft Institute]↗
DOE OSTI2024

Space Charge Dominated Momentum Spread and Compensation Strategies in the Post-Linac Section of Proton Improvement Plan-II at Fermilab

The upcoming Proton Improvement Plan-II (PIP-II), designated for enhancements to the Fermilab accelerator complex, features a Beam Transfer Line (BTL) that channels the beam from the linac exit to the booster. In the absence of longitudinal focusing beyond the superconducting linac, the beam experiences an elevated momentum spread, primarily due to nonlinear space-charge forces, surpassing the allowable limit of 2.1e-4. This study presents a detailed examination of the space-charge-induced momentum spread and outlines mitigative strategies. The investigation includes the fine-tuning of a de-buncher cavity, analyzed in terms of operating frequency, longitudinal location, and gap voltage, under both standard and perturbed beam conditions—specifically accounting for momentum jitter and energy variation. The impact of buncher cavity misalignments on the beam's longitudinal phase space is also assessed. The paper concludes by recommending an optimized cavity configuration to effectively mitigate the observed increase in momentum spread along the BTL.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

North Birmingham Housing Energy Baseline and Upgrade Strategies [Slides]

The community of North Birmingham, Alabama, participated in the Communities LEAP pilot program. As part of this technical assistance pilot, residential buildings, energy efficiency, and electrification were analyzed. This slide deck details the baseline analysis of residential buildings in the community and potential upgrade strategies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Equitable Strategies for Residential Building Energy Efficiency and Electrification in San José, California

Hotter summers, heat waves, wildfires, and droughts are already affecting San Jose residents, with historically marginalized communities impacted first and worst. The City of San Jose has ambitious goals to make the city climate-neutral by 2030 and serve as an example for cities to accelerate climate action around the world. Electrifying and decarbonizing residential buildings are important priorities to achieve San Jose's plans to reach carbon neutrality while enabling residents to live the "Good Life 2.0" - a vision that aligns with community-identified priorities of safety, health, freedom, community, and positive experiences. This technical assistance built upon the Electrify San Jose: Framework for Existing Building Electrification to identify actionable strategies to make single- and multi-family buildings both energy-efficient and all-electric. This report is intended to provide the San Jose Climate Smart team and their partners with relevant data, insights, and actionable analysis to aid in-depth and nuanced engagements with key stakeholders. In particular, the findings in this report highlight opportunities and challenges for San Jose City Council, residents, building owners, developers, financial institutions, and utility partners instrumental in building support and earning buy-in for energy efficiency and electrification upgrades in existing buildings.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Equitable Strategies for Residential Building Energy Efficiency and Electrification in San José, California [Slides]

Hotter summers, heat waves, wildfires, and droughts are already affecting San Jose residents, with historically marginalized communities impacted first and worst. The City of San Jose has ambitious goals to make the city climate-neutral by 2030 and serve as an example for cities to accelerate climate action around the world. Electrifying and decarbonizing residential buildings are important priorities to achieve San Jose's plans to reach carbon neutrality while enabling residents to live the "Good Life 2.0" - a vision that aligns with community-identified priorities of safety, health, freedom, community, and positive experiences. This technical assistance built upon the Electrify San Jose: Framework for Existing Building Electrification to identify actionable strategies to make single- and multi-family buildings both energy-efficient and all-electric. This report is intended to provide the San Jose Climate Smart team and their partners with relevant data, insights, and actionable analysis to aid in-depth and nuanced engagements with key stakeholders. In particular, the findings in this report highlight opportunities and challenges for San Jose City Council, residents, building owners, developers, financial institutions, and utility partners instrumental in building support and earning buy-in for energy efficiency and electrification upgrades in existing buildings.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Distributed Energy, Utility Scale: 30 Proven Strategies to Increase VPP Enrollment [Slides]

After decades of low or declining growth in electricity demand, the U.S. now faces a significant near-term need for new generation capacity and transmission and distribution infrastructure. Virtual Power Plants (VPPs) can meet a large portion of the gap between electricity supply and growing demand, but only if deployed at an increased scale. This study provides 30 proven strategies for scaling VPPs through increased enrollment based on in-depth interviews with utilities and VPP solutions providers that have achieved considerable scale or rapid growth in program deployment. The study includes specific actions for regulators, utilities, and VPP solutions providers to increase VPP enrollment and deliver important customer and utility benefits.

24 POWER TRANSMISSION AND DISTRIBUTION↗