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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Large enhancement of ferroelectric properties of perovskite oxides via nitrogen incorporation

Perovskite oxides have a wide variety of physical properties that make them promising candidates for versatile technological applications including nonvolatile memory and logic devices. Chemical tuning of those properties has been achieved, to the greatest extent, by cation-site substitution, while anion substitution is much less explored due to the difficulty in synthesizing high-quality, mixed-anion compounds. Here, nitrogen-incorporated BaTiO3 thin films have been synthesized by reactive pulsed-laser deposition in a nitrogen growth atmosphere. The enhanced hybridization between titanium and nitrogen induces a large ferroelectric polarization of 70 μC/cm2 and high Curie temperature of ~1213 K, which are ~2.8 times larger and ~810 K higher than in bulk BaTiO3, respectively. These results suggest great potential for anion-substituted perovskite oxides in producing emergent functionalities and device applications.

Wang, Tao↗
DOE OSTI2024

Transcriptomic Analysis of Arachidonic Acid Pathway Genes Provides Mechanistic Insight into Multi-Organ Inflammatory and Vascular Diseases

Arachidonic acid (AA) metabolites have been associated with several diseases across various organ systems, including the cardiovascular, pulmonary, and renal systems. Lipid mediators generated from AA oxidation have been studied to control macrophages, T-cells, cytokines, and fibroblasts, and regulate inflammatory mediators that induce vascular remodeling and dysfunction. AA is metabolized by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) to generate anti-inflammatory, pro-inflammatory, and pro-resolutory oxidized lipids. As comorbid states such as diabetes, hypertension, and obesity become more prevalent in cardiovascular disease, studying the expression of AA pathway genes and their association with these diseases can provide unique pathophysiological insights. In addition, the AA pathway of oxidized lipids exhibits diverse functions across different organ systems, where a lipid can be both anti-inflammatory and pro-inflammatory depending on the location of metabolic activity. Therefore, we aimed to characterize the gene expression of these lipid enzymes and receptors throughout multi-organ diseases via a transcriptomic meta-analysis using the Gene Expression Omnibus (GEO) Database. In our study, we found that distinct AA pathways were expressed in various comorbid conditions, especially those with prominent inflammatory risk factors. Comorbidities, such as hypertension, diabetes, and obesity appeared to contribute to elevated expression of pro-inflammatory lipid mediator genes. Our results demonstrate that expression of inflammatory AA pathway genes may potentiate and attenuate disease; therefore, we suggest further exploration of these pathways as therapeutic targets to improve outcomes.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Doubly-Charged Negative Ions as Novel Tunable Catalysts: Graphene and Fullerene Molecules Versus Atomic Metals

The fundamental mechanism underlying negative-ion catalysis involves bond-strength breaking in the transition state (TS). Doubly-charged atomic/molecular anions are proposed as novel dynamic tunable catalysts, as demonstrated in water oxidation into peroxide. Density Functional Theory TS calculations have found a tunable energy activation barrier reduction ranging from 0.030 eV to 2.070 eV, with Si 2– , Pu 2– , Pa 2– and Sn 2– being the best catalysts; the radioactive elements usher in new application opportunities. C 60 2– significantly reduces the standard C 60 – TS energy barrier, while graphene increases it, behaving like cationic systems. According to their reaction barrier reduction efficiency, variation across charge states and systems, rank-ordered catalysts reveal their tunable and wide applications, ranging from water purification to biocompatible antiviral and antibacterial sanitation systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Applications of Decellularized Plant Tissues in Regenerative Medicine and Tissue Engineering

The development of biomaterials capable of supporting complex tissue growth remains a central challenge in regenerative medicine and tissue engineering, particularly in replicating the structural, mechanical, and transport functions of native extracellular matrices. While decellularized animal tissues have demonstrated significant success as scaffolds for tissue engineering, they are still constrained by cost, immunogenicity, and ethical concerns. In recent years, decellularized plant tissues have emerged as a compelling alternative scaffold platform due to their inherent vascular architectures, ethical sourcing, tunable mechanical properties, cytocompatibility, and sustainability. This review summarizes current strategies for the decellularization of plant tissues, including chemical, enzymatic, and physical approaches, and discusses how these methods preserve plant cell wall structure while removing immunogenic components. Advances in surface loading and functionalization, including protein coatings, oxidation, nanoparticle incorporation, peptide conjugation, and bioactive molecule loading, have further enhanced cell adhesion, differentiation, biodegradability, and immunomodulation. Recent applications of decellularized plant scaffolds in cardiac, skeletal muscle, bone, nerve, and wound healing contexts are reviewed, highlighting proof-of-concept successes and remaining challenges. Beyond therapeutic applications, plant-derived scaffolds have also enabled physiologically relevant in vitro models for vascular biology, mechanotransduction, cancer, metabolic tissues, and drug response studies. Collectively, these advances position decellularized plant tissues as versatile, low-cost, and ethically favorable biomaterials with growing relevance for both regenerative medicine and tissue modeling.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1975

SSME-HAS dynamic load simulators

The space shuttle main engine propellant valve actuators (SSME) were designed to simulate the loads reflected into the SSME by the chamber coolant valve, the fuel preburner, and the oxidizer. The design, and functional description are included along with a list of the drawings. The load fixture control transform, friction torque, and flow calculations are reported.

Source record↗
NASA NTRS1977

Photochemistry of nitrogen in the Martian atmosphere

Models are developed for the photochemistry of a CO2-H2O-N2 atmosphere on Mars. Estimates are given for the concentrations of N, NO, NO2, NO3, N2O5, HNO2, HNO3, and N2O as a function of altitude. Nitric oxide is the most abundant form of odd nitrogen, present with a mixing ratio relative to CO2 of the order of 1 hundred-millionth. Deposition rates for nitrite and nitrate minerals could be as large as 300,000 N equivalent atoms per sq cm/sec under present conditions and may have been higher in the past.

Yung, Y. L.↗
NASA NTRS1977

Odd nitrogen in the mesosphere and thermosphere - Its chemistry and transport

The atomic nitrogen in the thermosphere, which is produced either in its ground term or in a highly reactive metastable term, reacts with molecular oxygen to form nitric oxide and atomic oxygen. However, nitric oxide is destroyed in reactions with atomic nitrogen in which molecular nitrogen and atomic oxygen is formed. Adopted reactions and rate coefficients for odd nitrogen chemistry are listed in a table. An analysis is conducted of the temperature distribution below 150 km and its effect on the odd nitrogen chemistry. The latitudinal distribution of nitric oxide is discussed. Satellite measurements have shown that nitric oxide concentrations at high latitudes are highly variable in both time and space. Their average concentrations are 3-4 times higher than at mid-latitudes. The measured variation of nitric oxide density as a function of latitude is shown in a graph.

Rusch, D. W.↗
NASA NTRS1986

Evolution of thiol protective systems in prokaryotes

Biological thiols are essential elements in most aspects of cell function but undergo rapid oxidation to disulfides in the presence of oxygen. The evolution of systems to protect against such oxygen toxicity was essential to the emergence of aerobic life. The protection system used by eukaryotes is based upon glutathione (GSH) and GSH-dependent enzymes but many bacteria lack GSH and apparently use other mechanisms. The objective of this research is to elaborate the thiol protective mechanisms employed by prokaryotes of widely divergent evolutionary origin and to understand why GSH became the central thiol employed in essentially all higher organisms. Thiol-selective fluorescent labeling and HPLC analysis has been used to determine key monothiol components.

Fahey, R. C.↗
NASA NTRS1986

Scandium oxide antireflection coatings for superluminescent LEDs

For an employment of laser diodes as superluminescent LEDs (SLDs) or amplifiers, the facets of the diodes must be coated with antireflection films. In the work reported, scandium oxide was evaporated from an e-beam source onto Supersil II fused silica substrates. The obtained samples were used for measurements of absorption and reflectivity. Results of index measurements on e-beam evaporated films are presented. It is shown that excellent coatings with reflectivities of 0.00025 can be obtained using these films. Attention is given to the refractive indices for scandium oxide films as a function of wavelength, the power output vs current for laser before coating and after coating with Sc2O3.

Ladany, I.↗
NASA NTRS1992

Development of an optical flameout detection system for High Temperature Wind Tunnels

This paper outlines the design and development of a flameout detection system for future use in the 8-Foot High Temperature Wind Tunnel (8' HTT) at the NASA Langley Research Center. The proposed system is required to function reliably in an oxidizing environment with pressures up to 28 MPa (4,000 psi), survive temperatures reaching 1700 C (3100 F), and respond with a shut-down signal upon flameout in less than 100 milliseconds. The 7-Inch High Temperature Pilot Tunnel (7" HTT), a one-twelfth scale version of the 8' HTT, was used to develop a prototype system and to obtain data on the spectral content of the flame during combustion. The design and development of the spectral data acquisition system for the 7" HTT is presented here.

Borg, Stephen E.↗
NASA NTRS1995

Plume particle collection and sizing from static firing of solid rocket motors

A unique dart system has been designed and built at the NASA Marshall Space Flight Center to collect aluminum oxide plume particles from the plumes of large scale solid rocket motors, such as the space shuttle RSRM. The capability of this system to collect clean samples from both the vertically fired MNASA (18.3% scaled version of the RSRM) motors and the horizontally fired RSRM motor has been demonstrated. The particle mass averaged diameters, d43, measured from the samples for the different motors, ranged from 8 to 11 mu m and were independent of the dart collection surface and the motor burn time. The measured results agreed well with those calculated using the industry standard Hermsen's correlation within the standard deviation of the correlation . For each of the samples analyzed from both MNASA and RSRM motors, the distribution of the cumulative mass fraction of the plume oxide particles as a function of the particle diameter was best described by a monomodal log-normal distribution with a standard deviation of 0.13 - 0.15. This distribution agreed well with the theoretical prediction by Salita using the OD3P code for the RSRM motor at the nozzle exit plane.

Sambamurthi, Jay K.↗
NASA NTRS2003

Microbial Fossils Detected in Desert Varnish

Mars Global Surveyor Thermal Emission Spectrometer data indicate regions with significant levels of hematite (_Fe2O3). Fe-oxides, like hematite, can form as aqueous mineral precipitates and as such may preserve microscopic fossils or other biosignatures. Several potential terrestrial analogues to martian hematite like hydrothermal vents have preserved microfossils. Microbial fossilization in Fe-oxides is often a function of biomineralization. For example, goethite (FeO2H) encrustation of fungal mycelia from the mid-Tertiary preserved fungal morphologies such that their genera could be determined.

Flood, B. E.↗
NASA NTRS2005

Using Remote Sensing Data to Evaluate Surface Soil Properties in Alabama Ultisols

Evaluation of surface soil properties via remote sensing could facilitate soil survey mapping, erosion prediction and allocation of agrochemicals for precision management. The objective of this study was to evaluate the relationship between soil spectral signature and surface soil properties in conventionally managed row crop systems. High-resolution RS data were acquired over bare fields in the Coastal Plain, Appalachian Plateau, and Ridge and Valley provinces of Alabama using the Airborne Terrestrial Applications Sensor multispectral scanner. Soils ranged from sandy Kandiudults to fine textured Rhodudults. Surface soil samples (0-1 cm) were collected from 163 sampling points for soil organic carbon, particle size distribution, and citrate dithionite extractable iron content. Surface roughness, soil water content, and crusting were also measured during sampling. Two methods of analysis were evaluated: 1) multiple linear regression using common spectral band ratios, and 2) partial least squares regression. Our data show that thermal infrared spectra are highly, linearly related to soil organic carbon, sand and clay content. Soil organic carbon content was the most difficult to quantify in these highly weathered systems, where soil organic carbon was generally less than 1.2%. Estimates of sand and clay content were best using partial least squares regression at the Valley site, explaining 42-59% of the variability. In the Coastal Plain, sandy surfaces prone to crusting limited estimates of sand and clay content via partial least squares and regression with common band ratios. Estimates of iron oxide content were a function of mineralogy and best accomplished using specific band ratios, with regression explaining 36-65% of the variability at the Valley and Coastal Plain sites, respectively.

Sullivan, Dana G.↗
NASA NTRS2005

Activation of nuclear transcription factor-kappaB in mouse brain induced by a simulated microgravity environment

Microgravity induces inflammatory responses and modulates immune functions that may increase oxidative stress. Exposure to a microgravity environment induces adverse neurological effects; however, there is little research exploring the etiology of these effects resulting from exposure to such an environment. It is also known that spaceflight is associated with increase in oxidative stress; however, this phenomenon has not been reproduced in land-based simulated microgravity models. In this study, an attempt has been made to show the induction of reactive oxygen species (ROS) in mice brain, using ground-based microgravity simulator. Increased ROS was observed in brain stem and frontal cortex with concomitant decrease in glutathione, on exposing mice to simulated microgravity for 7 d. Oxidative stress-induced activation of nuclear factor-kappaB was observed in all the regions of the brain. Moreover, mitogen-activated protein kinase kinase was phosphorylated equally in all regions of the brain exposed to simulated microgravity. These results suggest that exposure of brain to simulated microgravity can induce expression of certain transcription factors, and these have been earlier argued to be oxidative stress dependent.

Non-NASA Center↗
NASA NTRS2018

Simulated Space Radiation and Weightlessness: Vascular-Bone Coupling Mechanisms to Preserve Skeletal Health

We examined experimentally the effects of radiation and/or simulated weightlessness by hindlimb unloading on bone and blood vessel function either after a short period or at a later time after transient exposures in adult male, C57Bl6J mice. In sum, recent findings from our studies show that in the short term, ionizing radiation and simulate weightlessness cause greater deficits in blood vessels when combined compared to either challenge alone. In the long term, heavy ion radiation, but not unloading, can lead to persistent, adverse consequences for bone and vessel function, possibly due to oxidative stress-related pathways.

microgravity↗
NASA NTRS2017

Simulated Space Radiation and Weightlessness: Vascular-Bone Coupling Mechanisms to Preserve Skeletal Health

We examined experimentally the effects of radiation andor simulated weightlessness by hindlimb unloading on bone and blood vessel function either after a short period or at a later time after transient exposures in adult male, C57Bl6J mice. In sum, recent findings from our studies show that in the short term, ionizing radiation and simulate weightlessness cause greater deficits in blood vessels when combined compared to either challenge alone. In the long term, heavy ion radiation, but not unloading, can lead to persistent, adverse consequences for bone and vessel function, possibly due to oxidative stress-related pathways.

Microgravity↗
DOE OSTI2024

Photooxidation of Polyolefins to Produce Materials with In-Chain Ketones and Improved Materials Properties

Herein, we report a selective photooxidation of commodity postconsumer polyolefins to produce polymers with in-chain ketones. The reaction does not involve the use of catalyst, metals, or expensive oxidants, and selectively introduces ketone functional groups. Under mild and operationally simple conditions, yields up to 1.23 mol % of in-chain ketones were achieved. Installation of in-chain ketones resulted in materials with improved adhesion of the materials and miscibility of mixed plastics relative to the unfunctionalized plastics. The introduction of ketone groups into the polymer backbone allows these materials to react with diamines, forming dynamic covalent polyolefin networks. This strategy allows for the upcycling of mixed plastic waste into reprocessable materials with enhanced performance properties compared to polyolefin blends. Mechanistic studies support the involvement of photoexcited nitroaromatics in consecutive hydrogen and oxygen atom transfer reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1976

Advanced thermionic converter development

Recent progress at Thermo Electron in developing advanced thermionic converters is summarized with particular attention paid to the development of electrodes, diodes, and triodes. It is found that one class of materials (ZnO, BaO and SrO) provides interesting cesiated work functions (1.3-1.4 eV) without additional oxygen. The second class of materials studied (rare earth oxides and hexaborides) gives cesiated/oxygenated work functions of less than 1.2 eV. Five techniques of oxygen addition to thermionic converters are discussed. Vapor deposited tungsten oxide collector diodes and the reflux converter are considered.

Huffman, F. N.↗