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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Photocatalytic Transfer Hydrogenation in Water: Insight into Mechanism and Catalyst Speciation

Organometallic catalysts with strong metal-to-ligand charge-transfer (MLCT) optical transitions and reactive metal-hydride bonds provide opportunities for new excited-state reactivity. Toward this end, we have investigated photoinduced transfer hydrogenation reactions for a series of Cp*IrH complexes with functionalized bipyridyl ligands. Overcoming the baseline reactivity of this class of catalyst toward hydrogen evolution in aqueous media presents a major challenge for focusing this photochemical reactivity into desired transformations of more complex organic substrates. In this work, a photochemically induced aqueous ketone reduction catalyzed by [Cp*Ir(bpy)H][Cl] is reported and benchmarked to the competing hydrogen evolution reaction (HER). A detailed mechanistic study is conducted of the reduction of cyclohexanone with sodium formate delivering the reducing equivalent. Examining the kinetic profile of the cyclohexanone reduction revealed an unexpected induction period, suggesting a more complex underlying reaction mechanism where product selectivity was not simply a function of direct competition from a common excited-state reactive intermediate. The reaction kinetics were analyzed by variable time normalization analysis (VTNA), and the catalyst resting state was interrogated through operando light-emitting diode (LED) illumination H-1 NMR spectroscopy. Overall, these and other mechanistic studies provide insight into a photochemical reaction pathway to ketone reduction that is distinct from that previously reported for HER.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2016

Experimental Simulations of Lunar Magma Ocean Crystallization: The Plot (But Not the Crust) Thickens

Numerical models of differentiation of a global-scale lunar magma ocean (LMO) have raised as many questions as they have answered. Recent orbital missions and sample studies have provided new context for a large range of lithologies, from the comparatively magnesian "purest anorthosite" reported by to Si-rich domes and spinel-rich clasts with widespread areal distributions. In addition, the GRAIL mission provided strong constraints on lunar crustal density and average thickness. Can this increasingly complex geology be accounted for via the formation and evolution of the LMO? We have in recent years been conducting extensive sets of petrologic experiments designed to fully simulate LMO crystallization, which had not been attempted previously. Here we review the key results from these experiments, which show that LMO differentiation is more complex than initial models suggested. Several important features expected from LMO crystallization models have yet to be reproduced experimentally; combined modelling and experimental work by our group is ongoing.

Draper, D. S.↗
DOE OSTI2024

Alloying effects on deformation induced microstructure evolution in copper

In this work, we investigated the effects of alloying elements on plastic deformation and microstructure evolution in polycrystalline copper (Cu) and Cu alloyed with 1 wt. % lead (Cu-1 %Pb). These materials were selected due to the size mismatch between Cu and Pb, with the latter forming precipitates at grain boundaries. Multi-modal characterization techniques, including neutron diffraction, electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM), along with finite element simulations were employed to study the deformation behavior across multiple length scales. While both Cu and Cu-1%Pb exhibited similar macroscale response and final deformation textures, both dislocation line profile analysis and TEM revealed increased dislocation density in deformed Cu-1%Pb specimens. The presence of lead precipitates also significantly affected local plastic deformation during compression, with their influence diminishing with increasing strain. These results demonstrate the complex relationships between alloying elements, plastic deformation, microstructural evolution, and material behavior under load. The insights gained from this multi-scale and multi-technique approach contribute to the fundamental understanding of microstructural evolution in immiscible alloys and are valuable for tailoring the properties of structural materials for specific engineering applications.

36 MATERIALS SCIENCE↗
NASA NTRS2022

Structural and chemical complexity of minerals: An update

The complexities of chemical composition and crystal structure are fundamental characteristics of minerals that have high relevance to the understanding of their stability, occurrence and evolution. This review summarises recent developments in the field of mineral complexity and outlines possible directions for its future elaboration. The database of structural and chemical complexity parameters of minerals is updated by H-correction of structures with unknown H positions and the inclusion of new data. The revised average complexity values (arithmetic means) for all minerals are 3.54(2) bits/atom and 345(10) bits/cell (based upon 4443 structure reports). The distributions of atomic information amounts, chemIG and strIG, versus the number of mineral species fit the normal modes, whereas the distributions of total complexities, chemIG,total and strIG,total, along with numbers of atoms per formula and per unit cell are log normal. The three most complex mineral species known today are ewingite, morrisonite and ilmajokite, all either discovered or structurally characterised within the last five years. The most important complexity-generating mechanisms in minerals are: (1) the presence of isolated large clusters; (2) the presence of large clusters linked together to form three-dimensional frameworks; (3) formation of complex three-dimensional modular frameworks; (4) formation of complex modular layers; (5) high hydration state in salts with complex heteropolyhedral units; and (6) formation of ordered superstructures of relatively simple structure types. The relations between symmetry and complexity are considered. The analysis of temporal dynamics of mineralogical discoveries since 1875 with the step of 25 years show the increasing chemical and structural complexities of human knowledge of the mineral kingdom in the history of mineralogy. In the Earth’s history, both diversity and complexity of minerals experience dramatic increases associated with the formation of Earth’s continental crust, initiation of plate tectonics and the Great Oxidation event.

complexity↗
NASA NTRS2003

Interstellar Precursors of Meteoritic Organics

The organic inventory initially available to protostellar disks is the first step on the long chemical path to the development of Life. The early earth may have obtained most its volatile material from the arrival of meteorites and comets at its surface. Determining the most likely distribution of meteoritic and cometary organic molecules that could seed primitive planets is a major goal since it sets the initial conditions for, at least part of, the phase of prebiotic chemical evolution. Observations and measurements of the chemical composition of primitive Solar System organics, and of dense molecular clouds, should allow the construction of coherent theoretical picture of the development of organic complexity from interstellar biogenic material to the beginning of prebiotic evolution.

Charnley, S. B.↗
NASA NTRS1981

Mission operations computing systems evolution

As part of its preparation for the operational Shuttle era, the Goddard Space Flight Center (GSFC) is currently replacing most of the mission operations computing complexes that have supported near-earth space missions since the late 1960's. Major associated systems include the Metric Data Facility (MDF) which preprocesses, stores, and forwards all near-earth satellite tracking data; the Orbit Computation System (OCS) which determines related production orbit and attitude information; the Flight Dynamics System (FDS) which formulates spacecraft attitude and orbit maneuvers; and the Command Management System (CMS) which handles mission planning, scheduling, and command generation and integration. Management issues and experiences for the resultant replacement process are driven by a wide range of possible future mission requirements, flight-critical system aspects, complex internal system interfaces, extensive existing applications software, and phasing to optimize systems evolution.

Kurzhals, P. R.↗
NASA NTRS1991

Microwave simulations of a tropical rainfall system with a three-dimensional cloud model

A three-dinensional cloud model-microwave radiative transfer model combination is used to study the relations among the precipitation and other microphysical characteristics of a tropical oceanic squall line and the upwelling radiance at pertinent microwave frequencies. Complex brightness temperature-rain rate relations are evident at the full horizontal resolution (1.5 km) of the models, with spatial averaging producing smoother, shifter relations in most cases. Nonprecipitating cloud water is shown to be important in understanding the resulting distribution of brightness temperature. At the mature stage, convective portions of the cloud system are shown to produce different brightness temperature relations than the stratiform portion, primarily related to the distribution of cloud water. The evolution of the convective system from a small convective complex through its mature stage and the beginning of its dissipation also is shown to result in a variation of brightness temperature-rain relations, related to the distribution of cloud water and the evolution of ice in the precipitating system. The results of the study point to the need to take into account the evolution of nonprecipitating cloud water and precipitation-sized ice in the retrieval of rain from passive microwave space observations. This effect is evident for both the life cycle of individual convective elements and the life cycle of the convective system as a whole.

Adler, Robert A.↗
DOE OSTI2022

Comparative genomic and transcriptomic analyses of trans-kingdom pathogen Fusarium solani species complex reveal degrees of compartmentalization

Background: The Fusarium solani species complex (FSSC) comprises fungal pathogens responsible for mortality in a diverse range of animals and plants, but their genome diversity and transcriptome responses in animal pathogenicity remain to be elucidated. We sequenced, assembled and annotated six chromosome-level FSSC clade 3 genomes of aquatic animal and plant host origins. We established a pathosystem and investigated the expression data of F. falciforme and F. keratoplasticum in Chinese softshell turtle (Pelodiscus sinensis) host. Results: Comparative analyses between the FSSC genomes revealed a spectrum of conservation patterns in chromosomes categorised into three compartments: core, fast-core (FC), and lineage-specific (LS). LS chromosomes contribute to variations in genomes size, with up to 42.2% of variations between F. vanettenii strains. Each chromosome compartment varied in structural architectures, with FC and LS chromosomes contain higher proportions of repetitive elements with genes enriched in functions related to pathogenicity and niche expansion. We identified differences in both selection in the coding sequences and DNA methylation levels between genome features and chromosome compartments which suggest a multi-speed evolution that can be traced back to the last common ancestor of Fusarium. We further demonstrated that F. falciforme and F. keratoplasticum are opportunistic pathogens by inoculating P. sinensis eggs and identified differentially expressed genes also associated with plant pathogenicity. These included the most upregulated genes encoding the CFEM (Common in Fungal Extracellular Membrane) domain. Conclusions: The high-quality genome assemblies provided new insights into the evolution of FSSC chromosomes, which also serve as a resource for studies of fungal genome evolution and pathogenesis. This study also establishes an animal model for fungal pathogens of trans-kingdom hosts.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Programmable Catalyst Structures via Adsorbate-Induced Adatom Assembly

The electronic structure and geometric configuration of oxide-supported metal ions are important coordination properties that can be related to catalytic activity and stability. Herein, we interrogate the coordination environment of mononuclear Pd ions supported on ceria using CO adsorption, infrared vibrational spectroscopy, and DFT modeling. We observed the 15 h continuous co-evolution of a palladium- (2167 cm -1 ) and cerium-carbonyl (2177 cm -1 ) complex by monitoring the $\nu$(CO) infrared region. The slow CO adsorption kinetics were caused by the reactive ligand exchange between an oxygen atom of the support and the CO adsorbate to yield an oxygen vacancy and adsorbed CO 2 . We hypothesize that the co-evolved cerium-carbonyl complex was formed upon CO adsorption at or adjacent to this oxygen vacancy. Our hypothesis was experimentally supported by a dramatic attenuation of the cerium carbonyl signal upon pre-adsorption of water through an apparent competitive adsorption mechanism. The attenuation was also accompanied by a 6 cm -1 redshift of the palladium carbonyl band (2161 cm -1 ) attributed to hydrogen bonding between the carbonyl and a nearby hydroxyl. Characteristic n(CO) stretch frequencies catalogued through CO adsorption onto single crystal ceria by Wöll et al.1 led us to index the cerium carbonyl to the {100} nanofacet of the polycrystalline ceria support. It follows from the observed co-evolution of the two carbonyl complexes that Pd was also adsorbed at the {100} nanofacet. Redeployment of a previously developed DFT model by Ivanova-Shor et al.2 featuring square-planar coordination of Pd2+ at the {100} nanofacet (O 4 Pd) of a Ce 21 O 42 nanoparticle model qualitatively reproduced several experimental observations.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Spatio-temporal evolution of femtosecond laser pulses in dielectric multi-layers controlling the damage behavior

When designing femtosecond laser mirrors, one tries to minimize the peak intensity within the high-index layers to increase the laser-induced damage threshold. Typically, the optimization procedure utilizes the electric field distribution in the layer stack generated by monochromatic irradiation. Furthermore, this approach is sufficient for certain structures like high-reflectors based on quarter-wave films. More complex structures require to take into account the exact evolution of the pulse parameters such as peak intensity and duration within the multi-layer system. We exemplify this by discussing a merit function that can be included in femtosecond optics design.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Binding of the substrate analog methanol in the oxygen-evolving complex of photosystem II in the D1-N87A genetic variant of cyanobacteria

The solar water-splitting protein complex, photosystem II (PSII), catalyzes one of the most energetically demanding reactions in nature by using light energy to drive a catalyst capable of oxidizing water. The water oxidation reaction is catalyzed at the Mn 4 Ca-oxo cluster in the oxygen-evolving complex (OEC), which cycles through five light-driven S-state intermediates (S 0 –S 4 ). A detailed mechanism of the reaction remains elusive as it requires knowledge of the delivery and binding of substrate water in the higher S-state intermediates. In this paper, we use two-dimensional (2D) hyperfine sublevel correlation spectroscopy, in conjunction with quantum mechanics/molecular mechanics (QM/MM) and density functional theory (DFT), to probe the binding of the substrate analog, methanol, in the S 2 state of the D1-N87A variant of PSII from Synechocystis sp. PCC 6803. The results indicate that the size and specificity of the “narrow” channel is altered in D1-N87A PSII, allowing for the binding of deprotonated 13 C-labeled methanol at the Mn4(IV) ion of the catalytic cluster in the S 2 state. This has important implications on the mechanistic models for water oxidation in PSII.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2002

Rapid Modeling and Analysis Tools: Evolution, Status, Needs and Directions

Advanced aerospace systems are becoming increasingly more complex, and customers are demanding lower cost, higher performance, and high reliability. Increased demands are placed on the design engineers to collaborate and integrate design needs and objectives early in the design process to minimize risks that may occur later in the design development stage. High performance systems require better understanding of system sensitivities much earlier in the design process to meet these goals. The knowledge, skills, intuition, and experience of an individual design engineer will need to be extended significantly for the next generation of aerospace system designs. Then a collaborative effort involving the designer, rapid and reliable analysis tools and virtual experts will result in advanced aerospace systems that are safe, reliable, and efficient. This paper discusses the evolution, status, needs and directions for rapid modeling and analysis tools for structural analysis. First, the evolution of computerized design and analysis tools is briefly described. Next, the status of representative design and analysis tools is described along with a brief statement on their functionality. Then technology advancements to achieve rapid modeling and analysis are identified. Finally, potential future directions including possible prototype configurations are proposed.

Knight, Norman F., Jr.↗
NASA NTRSDate not supplied

OSIRIS-APEX: an OSIRIS-REx Extended Mission to Apophis

Goal 1: Establish the processes that drive the evolution of small asteroids, including tidal effects from close encounters with terrestrial planets. Goal 2: Determine the characteristics of an S-complex object to establish the link with its parent-asteroid family and its dynamical evolution from main belt through multiple Earth encounters. Goal 3: Examine the properties of an S-complex, potentially hazardous asteroid (PHA) as an analog for other PHAs and to defend the planet.

Asteroids↗
DOE OSTI2025

A generalizable machine learning-assisted fast Fourier transform algorithm to simulate the large strain phenomena in polycrystalline materials

Machine learning methods have shown initial promise in constitutive modeling for single crystals or homogenized polycrystals, delivering notable computational efficiency. However, existing machine learning-based constitutive models often lack generalizability, limiting their application across diverse boundary value problems. This study introduces a thermodynamics-informed artificial neural network model to accelerate rate-tangent crystal plasticity fast Fourier transform simulations for cross-scale deformation behaviors of polycrystals under complex loading. Our model integrates microstructural variability and local interactions effectively. To address local effects in each grain, we employ K-means clustering to group Gauss points within the microstructure into clusters assumed to be in similar mechanical states. This approach, based on self-clustering analysis, extends model scope from macroscopic stress response to the granular level, capturing mechanical responses and orientation evolution across grains. This reduces the number of nonlinear problems to solve, with cluster responses propagated throughout each group. The thermodynamics-based artificial neural network-extracted features are further processed using local material state clusters to account for history-dependent deformation and evolving microstructures. Additionally, representative volume element simulations with rate-tangent crystal plasticity fast Fourier transform provide reliable datasets for model training. The proposed model demonstrates high efficiency, accuracy, self-consistency, and enhanced generalizability in predicting strain–stress responses and orientation evolution at both individual grain and aggregate scales under complex loading conditions, such as biaxial tension and arbitrary loading scenarios.

36 MATERIALS SCIENCE↗
NASA NTRS2011

Evolution of the Florida Launch Site Architecture: Embracing Multiple Customers, Enhancing Launch Opportunities

The impending conclusion of the Space Shuttle Program and the Constellation Program cancellation unveiled in the FY2011 President's budget created a large void for human spaceflight capability and specifically launch activity from the Florida launch Site (FlS). This void created an opportunity to re-architect the launch site to be more accommodating to the future NASA heavy lift and commercial space industry. The goal is to evolve the heritage capabilities into a more affordable and flexible launch complex. This case study will discuss the FlS architecture evolution from the trade studies to select primary launch site locations for future customers, to improving infrastructure; promoting environmental remediation/compliance; improving offline processing, manufacturing, & recovery; developing range interface and control services with the US Air Force, and developing modernization efforts for the launch Pad, Vehicle Assembly Building, Mobile launcher, and supporting infrastructure. The architecture studies will steer how to best invest limited modernization funding from initiatives like the 21 st elSe and other potential funding.

Colloredo, Scott↗
NASA NTRSDate not supplied

Human Interfaces and Management of Information (HIMI) Challenges for “In-time” Aviation Safety Management Systems (IASMS)

The envisioned transformation of the National Airspace System to integrate an In-time Aviation Safety Management System(IASMS)to assure safety in Advanced Air Mobility(AAM)brings unprecedented challenges to the design of human interfaces and management of safety information. Safety in design and operational safety assurance are critical factors for how humans will interact with increasingly autonomous systems. The IASMS Concept of Operations builds from traditional commercial operator safety management and scales in complexity to AAM. The transformative changes in future aviation systems pose potential new critical safety risks with novel types of aircraft and other vehicles having different performance capabilities, flying in increasingly complex airspace, and using adaptive contingencies to manage normal and non-normal operations. These changes compel development of new and emerging capabilities that enable innovative ways for humans to interact with data and manage information. In-creasing complexity of AAM corresponds with use of predictive modeling, data analytics, machine learning, and artificial intelligence to effectively address known hazards and emergent risks. The roles of humans will dynamically evolve in increments with this technological and operational evolution. The interfaces for how humans will interact with increasingly complex and assured systems designed to operate autonomously and how information will need to be presented are important challenges to be resolved.

Lawrence J Prinzel↗