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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Manufacturing Oxide Dispersion Strengthened (ODS) steel plate via cold spray and friction stir processing

Oxide dispersion strengthened (ODS) steels, traditionally fabricated by ball milling and conventional powder metallurgy techniques to achieve bulk form, followed by intricate rolling and thermal treatment steps to achieve plate or sheet form. Here, we present a novel processing route that combines cold spray (CS) with friction stir processing (FSP) to manufacture ODS steel plate directly from gas atomization reaction synthesis (GARS)-prepared powder, thus no rolling steps involved. Microstructural and mechanical characterizations were performed to assess the quality and properties of the resulting ODS steel plate. Our findings demonstrate that the slightly porous CS deposited layer was fully consolidated after FSP, yielding a fully dense ODS steel plate that exhibited a favorable tradeoff between strength and ductility upon extraction from the substrate. Furthermore, through microstructural analysis, we revealed the presence of an appreciable density (∼10 22 /m 3 ) of nano-sized oxide particles, with the majority being smaller than 5 nm via the combined CS + FSP fabrication route. This work serves as a first proof-of-concept demonstration of the manufacturing approach described herein, offering a possible alternative route for producing ODS steel plates.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Electrification and decarbonization of spent Li-ion batteries purification by using an electrochemical membrane reactor

The expanding electric vehicle market brings with it exponential growth in the use of lithium (Li)-ion batteries (LIB) for which a wave of spent LIB is expected to come within the next 5 to 10 years. Due to the economic and strategic value imbedded within the metals contained in LIB, different recycling technologies, including hydrometallurgy, pyrometallurgy and direct recycling, are under development. Being different from previous hydrometallurgical methods, which may have high chemical consumption and negative environmental impact, an electrochemical membrane reactor is designed and validated for the first time, to electrify and decarbonize the impurity removal process. This reactor electroplates copper (Cu) and electrochemically precipitates aluminum (Al) and iron (Fe) from simulated spent LIB leachates, by consuming only air, water, and electricity, and the impurities are reduced to <1 ppm. The purified leachate maintains 99.5 % of the nickel (Ni), 95.4 % of the cobalt (Co) and 99.14 % of manganese (Mn) from the original leachate solution, and then can be directly applied for cathode precursor synthesis. Additionally, the purification process doesn’t introduce extra impurity, and the reactor restoration process generates valuable by-product hydro sulfate (H2SO4). This electrochemical process can reduce the cost, because of the much less chemical consumption and the valuable by-product generation, and mitigates the waste emissions, because of no extra impurity introduced and no greenhouse gas (GHG) produced. In conclusion, the chemical precipitation method uses significant amount of NaOH, which induced GHG emission during the manufacturing process.

25 ENERGY STORAGE↗
DOE OSTI2022

Triplet Energy Transfer from Lead Halide Perovskite for Highly Selective Photocatalytic 2 + 2 Cycloaddition

Triplet excitons are generally confined within a semiconductor. Hence, solar energy utilization via direct triplet energy transfer (TET) from semiconductors is challenging. TET from lead halide perovskite semiconductors to nearby organic molecules has been illustrated with ultrafast spectroscopy. Direct utilization of solar energy, i.e., visible light, via TET for photocatalysis is an important route but has not yet been demonstrated with lead halide perovskite semiconductors. Here, we show that a photocatalytic reaction, focusing on a 2 + 2 cycloaddition reaction, can been successfully demonstrated via TET from lead halide perovskite nanocrystals (PNCs). In this work, the triplet excitons are shown to induce a highly diastereomeric syn-selective 2 + 2 cycloaddition starting from olefins. Such photocatalytic reactions probe the TET process previously only observed spectroscopically. Moreover, our observation demonstrates that bulk-like PNCs (size, >10 nm; PL = 530 nm), in addition to quantum-confined smaller PNCs, are also effective for TET. Our findings may render a new energy conversion pathway to employ PNCs via direct TET for photocatalytic organic synthesis.

14 SOLAR ENERGY↗
NASA NTRS1992

Damage-mitigating control of aerospace systems for high performance and extended life

The concept of damage-mitigating control is to minimize fatigue (as well as creep and corrosion) damage of critical components of mechanical structures while simultaneously maximizing the system dynamic performance. Given a dynamic model of the plant and the specifications for performance and stability robustness, the task is to synthesize a control law that would meet the system requirements and, at the same time, satisfy the constraints that are imposed by the material and structural properties of the critical components. The authors present the concept of damage-mitigating control systems design with the following objectives: (1) to achieve high performance with a prolonged life span; and (2) to systematically update the controller as the new technology of advanced materials evolves. The major challenge is to extract the information from the material properties and then utilize this information in a mathematical form so that it can be directly applied to robust control synthesis for mechanical systems. The basic concept of damage-mitigating control is illustrated using a relatively simplified model of a space shuttle main engine.

Ray, Asok↗
NASA NTRS2013

Investigation of Truncated Waveguides

The design, fabrication, and performance of truncated circular and square waveguide cross-sections are presented. An emphasis is placed upon numerical and experimental validation of simple analytical formulae that describe the propagation properties of these structures. A test component, a 90-degree phase shifter, was fabricated and tested at 30 GHz. The concepts explored can be directly applied in the design, synthesis and optimization of components in the microwave to sub-millimeter wavebands.

Lourie, Nathan P.↗
NASA NTRSDate not supplied

Isolation Standard Measures: A Set of Validated and Feasible Measurements Ensuring Comparability Across Isolation and Confinement Studies

Isolation and confinement studies have been essential to the preparation of crewed long-duration space missions, acting as analogues that facilitate the study of psychological and physiological responses to isolation and confinement. They also serve as opportunities for the development, testing, and validation of countermeasures and coping methods to handle the challenges that arise in such scenarios. Due to the small sample sizes in combination with high inter-individual variability, single isolation campaigns are not always sufficient for obtaining statistically significant scientific findings. To address this issue and improve comparability between different studies, the need for standardized measures to be collected in all future isolation and confinement studies was identified. Additionally, these measures should also be shown to be generally valid, reliable, feasible and acceptable in analogue and spaceflight environments. Standard measures in isolation and confinement studies allow for more direct comparisons of results and synthesis of data across isolation and confinement studies as well as provide an important step toward standard measures in spaceflight. An international expert group with representatives from different space agencies worldwide was brought together to define a core set of standard measures for isolation and confinement studies. This paper provides an overview of the expert group’s recommendations for international standard measures for future isolation and confinement studies, along with subsequent updates coordinated by the International Countermeasures Working Group (ICMWG), which was established as a sub-Working Group under the International Space Life Sciences Working Group (ISLSWG). Additional experts were consulted by the ICMWG partner agencies as required. The collection of the described set of isolation standard measures will provide data on the following parameters: sleep, mood, psychological state, psychophysiology, cognitive performance, stress and the immune system, general health and well-being, team measures, nutritional measures, and environmental conditions. For each measure, recommendations were made about duration and frequency of administration, along with specific implementation recommendations in relation to the duration of the isolation study. The set of isolation standard measures will be reassessed every two years at a minimum to ensure they are up to date and reflect the current state-of-the-art.

Isolation↗
DOE OSTI2023

Synthesis of PHI-type zeolite harmotome using barium as an inorganic structure-directing agent inspired from natural mineral compositions

Zeolites are nanoporous aluminosilicates widely used as commercial adsorbents, heterogeneous catalysts, and ion-exchange materials due to their unique porosity, acidity, and thermal stability. The vast majority of synthetically-realized zeolite structures are prepared under hydrothermal conditions in alkaline media, and often in the presence of an organic structure-directing agent that facilitates the crystallization of diverse porous networks. Due to economic and environmental disadvantages of organic-based syntheses, it is often desirable to produce zeolites in organic-free media using alkali metal ions as the most commonly employed inorganic structure-directing agents (ISDAs). Here, in this study, we were inspired by the elemental compositions of natural zeolite minerals to examine the use of an alkaline earth metal ion as the ISDA to prepare zeolites with the PHI framework type. Two natural minerals exhibiting this crystal structure are phillipsite and harmotome. Both structures contain sodium and potassium as extra-framework cations, but only harmotome contains barium cations. Here we examined how the combination of alkali and alkaline earth ISDAs promote the formation of PHI-type zeolites. Our findings reveal that each isostructure is prepared under different synthesis conditions where simply adding barium to a growth mixture does not always lead to harmotome formation. Harmotome is formed in more dilute and alkaline growth media; however, time-resolved analyses of zeolite crystallization reveal that harmotome can be synthesized at low temperatures (ca. 65 °C) with rates that are 5-times faster than syntheses of phillipsite. This seemingly indicates that barium reduces the energetic barrier for PHI-type zeolite nucleation in ways that are not fully understood. Moreover, harmotome crystals exhibit an average particle size of ca. 60 nm, which is nearly 40-fold smaller than phillipsite crystals prepared under similar conditions. Collectively, these findings identify routes to control crystallization of PHI-type zeolites and may provide a broader strategy for using the composition of natural zeolite minerals to optimize the preparation of synthetic analogues.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Influence of “Non-Interacting” Flux Concentration in Metallic Flux Growth Synthesis

In situ experiments probing the mechanisms of flux growth synthesis above 1100 °C, though challenging, enable direct observation of synthetic pathways, products, and metastable phases. In this study, in situ powder X-ray diffraction of flux growth synthesis up to 1200 °C was employed to investigate the role of Sn flux in the synthesis of praseodymium cobalt germanides. We demonstrate that metallic fluxes, with minimal incorporation into the target compounds, significantly influence the reaction products of flux growth synthesis of intermetallic compounds. Furthermore, the validation of in situ experiments with bulk synthesis is also presented.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Selective CW Laser Synthesis of MoS2 and Mixture of MoS2 and MoO2 from (NH4)2MoS4 Film

Very recently, the synthesis of 2D MoS2 and WS2 through pulsed laser-directed thermolysis can achieve wafer-scale and large-area structures, in ambient conditions. In this paper, we report the synthesis of MoS2 and MoS2 oxides from (NH4)2MoS4 film using a visible continuous-wave (CW) laser at 532 nm, instead of the infrared pulsed laser for the laser-directed thermolysis. The (NH4)2MoS4 film is prepared by dissolving its crystal powder in DI water, sonicating the solution, and dip-coating onto a glass slide. We observed a laser intensity threshold for the laser synthesis of MoS2, however, it occurred in a narrow laser intensity range. Above that range, a mixture of MoS2 and MoO2 is formed, which can be used for a memristor device, as demonstrated by other research groups. We did not observe a mixture of MoS2 and MoO3 in the laser thermolysis of (NH4)2MoS4. The laser synthesis of MoS2 in a line pattern is also achieved through laser scanning. Due to of the ease of CW beam steering and the fine control of laser intensities, this study can lead toward the CW laser-directed thermolysis of (NH4)2MoS4 film for the fast, non-vacuum, patternable, and wafer-scale synthesis of 2D MoS2.

(NH4)2MoS4↗
NASA NTRS1986

The integrated manual and automatic control of complex flight systems

The topics of research in this program include pilot/vehicle analysis techniques, identification of pilot dynamics, and control and display synthesis techniques for optimizing aircraft handling qualities. The project activities are discussed. The current technical activity is directed at extending and validating the active display synthesis procedure, and the pilot/vehicle analysis of the NLR rate-command flight configurations in the landing task. Two papers published by the researchers are attached as appendices.

Schmidt, D. K.↗
NASA NTRS2001

Mechanistic Studies of Combustion and Structure Formation During Synthesis of Advanced Materials

Combustion in a variety of heterogeneous systems, leading to the synthesis of advanced materials, is characterized by high temperatures (2000-3500 K) and heating rates (up to 10(exp 6) K/s) at and ahead of the reaction front. These high temperatures generate liquids and gases which are subject to gravity-driven flow. The removal of such gravitational effects is likely to provide increased control of the reaction front, with a consequent improvement in control of the microstructure of the synthesized products. Thus, microgravity (mu-g) experiments lead to major advances in the understanding of fundamental aspects of combustion and structure formation under the extreme conditions of the combustion synthesis (CS) wave. In addition, the specific features of microgravity environment allow one to produce unique materials, which cannot be obtained under terrestrial conditions. The current research is a logic continuation of our previous work on investigations of the fundamental phenomena of combustion and structure formation that occur at the high temperatures achieved in a CS wave. Our research is being conducted in three main directions: 1) Microstructural Transformations during Combustion Synthesis of Metal-Ceramic Composites. The studies are devoted to the investigation of particle growth during CS of intermetallic-ceramic composites, synthesized from nickel, aluminum, titanium, and boron metal reactants. To determine the mechanisms of particle growth, the investigation varies the relative amount of components in the initial mixture to yield combustion wave products with different ratios of solid and liquid phases, under 1g and mu-g conditions; 2) Mechanisms of Heat Transfer during Reactions in Heterogeneous Media. Specifically, new phenomena of gasless combustion wave propagation in heterogeneous media with porosity higher than that achievable in normal gravity conditions, are being studied. Two types of mixtures are investigated: clad powders, where contact between reactants occurs within each particle, and mixtures of elemental powders, where interparticle contacts are important for the reaction; and 3) Mechanistic Studies of Phase Separation in Combustion of Thermite Systems. Studies are devoted to experiments on thermite systems (metal oxide-reducing metal) where phase separation processes occur to produce alloys with tailored compositions and properties. The separation may be either gravity-driven or due to surface forces, and systematic studies to elucidate the true mechanism are being conducted. The knowledge obtained will be used to find the most promising ways of controlling the microstructure and properties of combustion-synthesized materials. Low-gravity experiments are essential to create idealized an environment for insights into the physics and chemistry of advanced material synthesis processes.

Varma, A.↗
NASA NTRS1990

Feasibility study of a synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas

Surface errors on parabolic reflector antennas degrade the overall performance of the antenna. Space antenna structures are difficult to build, deploy and control. They must maintain a nearly perfect parabolic shape in a harsh environment and must be lightweight. Electromagnetic compensation for surface errors in large space reflector antennas can be used to supplement mechanical compensation. Electromagnetic compensation for surface errors in large space reflector antennas has been the topic of several research studies. Most of these studies try to correct the focal plane fields of the reflector near the focal point and, hence, compensate for the distortions over the whole radiation pattern. An alternative approach to electromagnetic compensation is presented. The proposed technique uses pattern synthesis to compensate for the surface errors. The pattern synthesis approach uses a localized algorithm in which pattern corrections are directed specifically towards portions of the pattern requiring improvement. The pattern synthesis technique does not require knowledge of the reflector surface. It uses radiation pattern data to perform the compensation.

Stutzman, W. L.↗
NASA NTRS1992

A pattern synthesis technique for array feeds to improve radiation performance of large distorted reflector antennas

Technologies exist for construction of antennas with adaptive surfaces that can compensate for many of the larger distortions caused by thermal and gravitational forces. However, as the frequency and size of the reflectors increase, the subtle surface errors become significant and degrade the overall electromagnetic performance. Electronic compensation through an adaptive feed array offers a means for mitigation of surface distortion effects. A pattern synthesis approach for electromagnetic compensation of surface error is presented. The pattern synthesis approach uses a localized algorithm in which pattern corrections are directed toward specific portions of the pattern requiring improvement. The pattern synthesis technique uses radiation pattern data to perform the compensation.

Smith, William T.↗
DOE OSTI2026

In-Situ Ligand-Induced Chirality Transfer in Emissive CdSe Nanoplatelets

Terminating semiconductor nanocrystals with chiral organic ligands can induce chiroptical properties that combine the chiral character of the ligands with the strong and tunable optical properties of the nanocrystal. However, the synthesis of such chiral-modified nanocrystals is currently limited by solvent incompatibility between polar chiral ligands and nonpolar traditional ligands, as well as by ligand dissolution behavior that ultimately compromises nanocrystal quality and the degree to which chiroptical properties can be manipulated. In this work, we demonstrate a single-step synthesis of chiral cadmium selenide (CdSe) nanoplatelets (NPLs) that eliminates the need for postsynthetic ligand exchange in aqueous solvents, resulting in highly emissive chiral CdSe NPLs. By directly incorporating chiral aminodecanoic acid ligands during synthesis, we achieve in situ ligand binding and chirality transfer to CdSe NPLs. This approach produces CdSe NPLs with high photoluminescence quantum efficiencies of 50% and circular dichroism dissymmetry factors (gCD) on the order of 10 –4 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1989

Some acyclic analogues of nucleotides and their template-directed reactions

Bismonophosphoimidazolides of acyclic analogues of guanosine IV and adenosine V were synthesized. They undergo oligomerization in the presence of complementary polynucleotide templates. Details of their synthesis and their subsequent template- and nontemplate-directed reactions are described, and their possible relevance to the origin of life is discussed.

Tohidi, Mahrokh↗
NASA NTRS1989

Feasibility study of a synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas

Surface errors on parabolic reflector antennas degrade the overall performance of the antenna. The errors are in the form of roughness on the surface, distortions in the shape, or structural design details. They cause amplitude and phase errors in the aperture field which lower the gain, raise the sidelobes, and fill in the nulls. These are major problems in large space reflector antennas. Planned mobile satellite communications systems having limited signal margin need high gain from the space reflectors. Future multiple beam antenna systems requiring spatial isolation to allow frequency reuse could be rendered useless if high sidelobes are present. High sidelobes are also responsible for noise. Ways of compensating for surface errors by pattern synthesis using an array of feed antennas are examined. Pattern corrections are directed specifically toward portions of the pattern requiring improvements. The pattern synthesis does not require knowledge of the surface errors. Both the amplitude and phase of the high side lobes caused by the distortion are required.

Stutzman, W. L.↗
NASA NTRS1985

Alternative approximation concepts for space frame synthesis

A structural synthesis methodology for the minimum mass design of 3-dimensionall frame-truss structures under multiple static loading conditions and subject to limits on displacements, rotations, stresses, local buckling, and element cross-sectional dimensions is presented. A variety of approximation concept options are employed to yield near optimum designs after no more than 10 structural analyses. Available options include: (A) formulation of the nonlinear mathematcal programming problem in either reciprocal section property (RSP) or cross-sectional dimension (CSD) space; (B) two alternative approximate problem structures in each design space; and (C) three distinct assumptions about element end-force variations. Fixed element, design element linking, and temporary constraint deletion features are also included. The solution of each approximate problem, in either its primal or dual form, is obtained using CONMIN, a feasible directions program. The frame-truss synthesis methodology is implemented in the COMPASS computer program and is used to solve a variety of problems. These problems were chosen so that, in addition to exercising the various approximation concepts options, the results could be compared with previously published work.

Lust, R. V.↗