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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Supporting flight data analysis for Space Shuttle Orbiter experiments at NASA Ames Research Center

The space shuttle orbiter experiments program is responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The infrared imagery of shuttle (IRIS), catalytic surface effects, and tile gap heating experiments sponsored by Ames Research Center are part of this program. The software required to process the flight data which support these experiments is described. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques provide information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third shuttle mission.

Green, M. J.↗
NASA NTRS1983

Supporting flight data analysis for Space Shuttle Orbiter Experiments at NASA Ames Research Center

The Space Shuttle Orbiter Experiments program in responsible for collecting flight data to extend the research and technology base for future aerospace vehicle design. The Infrared Imagery of Shuttle (IRIS), Catalytic Surface Effects, and Tile Gap Heating experiments sponsored by Ames Research Center are part of this program. The paper describes the software required to process the flight data which support these experiments. In addition, data analysis techniques, developed in support of the IRIS experiment, are discussed. Using the flight data base, the techniques have provided information useful in analyzing and correcting problems with the experiment, and in interpreting the IRIS image obtained during the entry of the third Shuttle mission.

Green, M. J.↗
NASA NTRS1983

Orbiter windward surface entry Heating: Post-orbital flight test program update

Correlations of orbiter windward surface entry heating data from the first five flights are presented with emphasis on boundary layer transition and the effects of catalytic recombination. Results show that a single roughness boundary layer transition correlation developed for spherical element trips works well for the orbiter tile system. Also, an engineering approach for predicting heating in nonequilibrium flow conditions shows good agreement with the flight test data in the time period of significant heating. The results of these correlations, when used to predict orbiter heating for a high cross mission, indicate that the thermal protection system on the windward surface will perform successfully in such a mission.

Harthun, M. H.↗
NASA NTRS1993

Test model designs for advanced refractory ceramic materials

The next generation of space vehicles will be subjected to severe aerothermal loads and will require an improved thermal protection system (TPS) and other advanced vehicle components. In order to ensure the satisfactory performance system (TPS) and other advanced vehicle materials and components, testing is to be performed in environments similar to space flight. The design and fabrication of the test models should be fairly simple but still accomplish test objectives. In the Advanced Refractory Ceramic Materials test series, the models and model holders will need to withstand the required heat fluxes of 340 to 817 W/sq cm or surface temperatures in the range of 2700 K to 3000 K. The model holders should provide one dimensional (1-D) heat transfer to the samples and the appropriate flow field without compromising the primary test objectives. The optical properties such as the effective emissivity, catalytic efficiency coefficients, thermal properties, and mass loss measurements are also taken into consideration in the design process. Therefore, it is the intent of this paper to demonstrate the design schemes for different models and model holders that would accommodate these test requirements and ensure the safe operation in a typical arc jet facility.

Tran, Huy Kim↗
DOE OSTI2023

The NO reduction by CO over NiO x /CeO 2 catalysts with a fixed Ni surface density: pretreatment effects on the catalyst structure and catalytic activity

NiO x /CeO 2 catalysts have shown promising results in various catalytic reactions, including the NO reduction by CO. Here, in this study, we investigated the effect of oxidation and reduction treatments on the NO reduction by CO over pretreated NiO x /CeO 2 catalysts. A series of oxidized and reduced supported NiO x catalysts were synthesized in two steps: (1) the pretreatment of CeO 2 supports at different temperatures (400, 500, and 700 °C) under oxidizing and reducing conditions and (2) the synthesis of NiO x /CeO 2 catalysts by an incipient wetness impregnation method (IWI) with a fixed surface density of 5.3 Ni per nm 2 under specific conditions (oxidation/reduction) applied during the CeO 2 treatment. The prepared catalysts were characterized via BET, ICP/OES, Raman, XPS, and XRD to understand their physicochemical properties. The results showed that as the pretreatment temperature increased, the physicochemical properties of NiO x /CeO 2 catalysts were changed: a decreased specific surface area (SSA), decreased oxygen vacancy/defect sites, and an increased crystallite size. The oxidized NiO x /CeO 2 catalyst at a lower pretreatment temperature displayed a better catalytic activity, indicating that the physicochemical properties of the catalysts were key factors in enhancing the catalytic activity. To understand the intermediate species and reaction mechanism during the NO reduction by CO, an in situ DRIFTS study was performed and a possible reaction mechanism was also discussed.

36 MATERIALS SCIENCE↗
NASA NTRS1973

Equilibrium concentrations of N2H4 and its decomposition products at elevated temperatures and pressures

Liquid hydrazine is considered as a convenient source of hydrogen rather than just as a rocket fuel. For such purposes, the hydrogen is usually obtained by passing the hydrazine through a heated catalytic bed. One convenient measure of the effectiveness of a catalytic decomposition device as a whole is to compare the quantity of hydrogen produced with the equilibrium concentration of the gaseous species N2H4, NH3, N3, and H2 which would exist at the temperature and pressure found in various parts of the device. Calculations of the concentrations were carried out and are reported here. Following presentation of the results in both tabular and graphical forms is a comparison between the computed equilibrium concentrations and available experimental data.

Smetana, F. O.↗
DOE OSTI2026

Mitigation of polysulfide shuttle effect in Li-S batteries through catalytic disproportionation reaction

Polysulfides are poorly retained within porous cathodes and readily diffuse into the electrolyte over time, leading to the well-known shuttle effect that undermines the reversibility of Li-S batteries. Here, in this study, we demonstrate that catalytic disproportionation of polysulfides provides an effective pathway to suppress this process by rapidly converting dissolved species into solid sulfur and sulfides, thereby preventing their migration into the electrolyte. Fundamentally, the sluggish kinetics of sulfur redox reactions are responsible for the accumulation and redistribution of soluble polysulfides in the bulk electrolyte. By accelerating these kinetics, catalyzed disproportionation not only confines sulfur within the conductive cathode matrix but also promotes the homogeneous precipitation of Li₂S₂/Li₂S, which enhances electrochemical reversibility and cycling stability. Using nitrogen-doped carbon (NC800) as a model catalyst, we reveal its ability to drive a pseudo-16-electron reduction pathway, leading to a single dominant Li₂S product and uniform deposition within the porous framework. In contrast, a non-catalytic carbon (KB) yields multiple polysulfide intermediates and heterogeneous deposition. The mechanistic insights provided here highlight the pivotal role of catalytic disproportionation in reshaping sulfur redox pathways and offer a rational strategy for mitigating polysulfide shuttling in practical Li-S pouch cells.

25 ENERGY STORAGE↗
DOE OSTI2022

Adsorption and Catalytic Activity of Gold Nanoparticles in Mesoporous Silica: Effect of Pore Size and Dispersion Salinity

The assembled state of nanoparticles (NPs) within porous matrices plays a governing role in directing their biological, electronic, and catalytic properties. However, the effects of the spatial confinement and environmental factors, such as salinity, on the NP assemblies within the pores are poorly understood. In this study, we use adsorption isotherms, spectrophotometry, and small-angle neutron scattering to develop a better understanding of the effect of spatial confinement on the assembled state and catalytic performance of gold (Au) NPs in propylamine-functionalized SBA-15 and MCM-41 mesoporous silica materials (mSiO 2 ). We carry out a detailed investigation of the effect of pore diameter and ionic strength on the packing and spatial distribution of AuNPs within mSiO 2 to get a comprehensive insight into the structure, functioning, and activity of these NPs. We demonstrate the ability of the adsorbed AuNPs to withstand aggregation under high salinity conditions. We attribute the observed preservation of the adsorbed state of AuNPs to the strong electrostatic attraction between oppositely charged pore walls and AuNPs. The preservation of the structure allows the AuNPs to retain their catalytic activity for a model reaction in high salinity aqueous solution, here, the reduction of p-nitrophenol to p-aminophenol, which otherwise is significantly diminished due to bulk aggregation of the AuNPs. This fundamental study demonstrates the critical role of confinement and dispersion salinity on the adsorption and catalytic performance of NPs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Elucidation of Ce/Zr ratio effects on the physical properties and catalytic performance of CuO x /Ce y Zr 1− y O 2 catalysts

Although cerium oxide (CeO 2 ) is widely used as a catalyst support, its limited defect sites and surface oxygen vacancy/mobility should be improved. The incorporation of zirconium (Zr) in the cerium (Ce) lattice is shown to increase the number of oxygen vacancies and improve catalytic activity. Using a fixed surface density (SD) of copper (∼2.3 Cu atoms per nm 2 ) as a surface species, the role of the support (Ce y Zr 1−y O 2 (y = 1.0, 0.9, 0.6, 0.5, and 0.0)) and defect site effects in the CO oxidation reaction was investigated. Spectroscopic (e.g., Raman, XRD, XPS) and microscopic (e.g., SEM-EDX, HR-TEM) characterization techniques were applied to evaluate the defect sites, crystallite size, lattice parameters, chemical composition, oxidation states of elements and microstructure of the catalysts. Here, the CO oxidation reaction with varied CO : O 2 ratios (1 : 5, 1 : 1, and 1 : 0.5 (stoichiometric)) was used as a model reaction to describe the relationship between the structure and the catalytic performance of each catalyst. Based on the characterization results of Ce y Zr 1−y O 2 materials, the addition of Zr causes physical and chemical changes to the overall material. The inclusion of Zr into the structure of CeO 2 decreased the overall lattice parameter of the catalyst and increased the number of defect sites. The prepared catalysts were able to reach complete CO conversion (∼100%) at low temperature conditions (<200 °C), each showing varied reaction activity. The difference in CO oxidation activity was then analyzed and related to the structure, wherein Cu loading, surface oxygen vacancies, reduction–oxidation ability, CuO x –support interaction and oxygen mobility in the catalyst were the crucial descriptors.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Catalytic Resonance Theory: Turnover Efficiency and the Resonance Frequency

Programmable catalysts exhibiting forced oscillation in the free energy of reacting surface species were simulated to understand the general mechanisms leading to efficient use of the input energy. Catalytic ratchets with either positive or negative adsorbate scaling exhibited oscillation conditions of both high and low turnover efficiency, yielding catalytic turnover frequencies either close to or significantly lower than the applied catalyst oscillation frequency, respectively. The “effective rate”, defined as the product of the catalytic turnover frequency and the turnover efficiency (ηTOE), was limited via two catalytic mechanisms: a leaky catalytic ratchet existed when molecules repeatedly traversed backward through the catalytic transition state upon catalyst oscillation, while a catalytic ratchet with low surface participation exhibited reduced formation of a gas-phase final product due to low surface product coverage. Furthermore, a single applied frequency yielding a maximum effective catalytic rate defined as the “resonance frequency” provided maximum combined benefit for catalytic rate and efficiency.

25 ENERGY STORAGE↗
DOE OSTI2022

The effect of silica oxide support on the catalytic activity of nickel-molybdenum bimetallic catalyst toward ethanol steam reforming for hydrogen production

This work investigates the effects of molybdenum promoter and silica oxide (SiO 2 ) support morphology on the ethanol steam reforming (ESR) performance of Nickel-Molybdenum (NiMo) bimetallic catalysts. Ordered mesoporous SiO 2 (SBA-15) and commercial SiO 2 supports were used as the oxide support materials. The synthesized catalysts were prepared via the wet impregnation method and characterized via XRD, H 2 -TPR, BET, FTIR, and Raman techniques. This study shows that NiMo bimetallic catalyst supported on SBA-15 has superior catalytic activity and better coking resistance at an intermediate temperature of 600 ⁰C than commercial SiO 2 supported catalysts. The presence of a uniform mesoporous structure of SBA-15 with an average pore diameter of ~ 2 nm can obstruct the carbon formation, leading to improved coking resistance. The catalytic enhancement of NiMo bimetallic catalysts toward ESR can also be linked to the ability of Mo promoter in enhancing the interaction between NiMo nanoparticles and SiO 2 support materials and restraining agglomeration of Ni nanoparticles, which results in further improvement of NiMo nanoparticle dispersion and inhibit its sintering. The NiMo bimetallic catalysts supported on SBA-15 illustrated the high H 2 yield of ~ 54% and carbon conversion of ~ 89% with the excellent stability for ESR performed at 600 ⁰C and the steam-to-carbon ratio of 2 over 65 hours.

25 ENERGY STORAGE↗
DOE OSTI2022

Effect of Macro- and Microstructures on Catalytic Hydrogenolysis of Polyolefins

Here, polyethylenes of varying molecular weight and branch density, as well as polypropylenes of varying molecular weight and tacticity, were catalytically converted to lower-molecular-weight liquid products to showcase how these various properties in a mixed waste plastic stream could affect the final product. A Pt nanoparticle on a strontium titanate nanocuboid (Pt/STO) catalyst was used under solvent-free conditions in the presence of 170 psi of H 2 at 300 °C for hydrogenolysis. The initial molecular weight of polyethylene was found to have a moderate effect on the yield to the final product (ranging from 55 wt% for M n ~ 7600 Da to 67 wt% for M n ~ 50,950 Da). The microstructure, defined as the length and density of branches in a polymer, of higher-molecular-weight polymers was the dominant factor in determining the yield (ranging from 67 wt% for M n ~ 50,950 Da for linear low-density polyethylene (LLDPE) with C 2 branches to 97 wt% for M n ~ 38,850 Da for LLDPE with C 6 branches). The same products (M n = C 29 –C 46 , Ð = 1.1–1.6) and distribution of undesired light gases (C 1 –C 4 ≈ 90 mol%, C 5 –C 8 ≈ 10 mol%) are obtained from conversions of PE of varying molecular weight. The tacticity of polypropylene at a given molecular weight had a significant effect on the molecular weight of the final product, while not strongly affecting conversion. Hydrogenolysis of isotactic polypropylene (iPP) produced ≈C 18 with a wider polydispersity (Ð ~ 1.4) compared to the narrow ≈C 64 (Ð ~ 1.0) and ≈C 54 (Ð ~ 1.0) products from atactic (aPP) and syndiotactic (sPP) polypropylene, respectively. The stereochemistry of the methyl groups dictates the shape and structure of the polymer in the melt, which in turn affects how the hydrocarbon chain interacts with the catalyst surface, thereby impacting the number of C–C scissions. These results show how various characteristics such as the molecular weight and structure of a waste plastic stream could affect the final product.

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

Catalytic Autoxidation for Depolymerization of Multilayer Plastic Films

Recycling multilayer plastic films is challenged by a diversity of polymers, prompting development of new recycling methods. For the depolymerization of mixed polymers like those in multilayer films, metal-catalyzed autoxidation offers a versatile chemical recycling method to deconstruct multiple polymers to useful oxygenates. Here, we demonstrate that catalytic autoxidation is effective for depolymerizing multilayer films across diverse chemistries. We investigated conditions for a model polyethylene substrate using a Co, Mn, and Br cocatalyst system, achieving full carbon closure with oxygenated small molecules contributing up to 48 mol% carbon. Subsequently, we characterized product distributions for several common polymers used in multilayer films using high-resolution mass spectrometry (HRMS) and developed analytical methods to quantify the resulting complex product streams. Optimized conditions for polyethylene were applied to 11 multilayer plastic films containing 10 different polymers, including films with nonpolymeric potential disrupters like aluminum foil and titanium dioxide, showing that catalytic autoxidation is effective across a broad range of polymer types and is resistant to disrupters and additives. The generation of CO 2 in these reactions overall suggests that both reaction engineering and modifications to the reaction conditions will be required to achieve higher yields of soluble oxygenated products.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Effect of alkali metal addition on catalytic performance of Ag/ZrO 2 /SBA-16 catalyst for single-step conversion of ethanol to butadiene

Here, we describe how adding Na and K to a 4Ag/4ZrO 2 /SBA-16 catalyst enhances catalytic performance for single-bed conversion of ethanol to butadiene. While adding Na and K leads to a slight decrease in conversion (i.e., ~10% loss), the production of desired butadiene is significantly increased with up to 50% improvement in productivity for the 4Ag/4ZrO 2 /SBA-16 catalyst promoted with 0.5% Na. The reasons for this improvement are a beneficial decrease in Lewis acid site concentration and higher Ag dispersion when Na or K are added, which results in decreased activity involving ethanol dehydration to ethylene and diethyl ether. A remarkable butadiene selectivity of 75% was achieved while maintaining high conversion (i.e., 90%) with 0.5Na/4Ag/4ZrO 2 /SBA-16 catalyst. A 72-hour catalyst lifetime study shows that because of higher coke formation from polymerization of desired butadiene, catalyst deactivation occurs more rapidly with the 0.5Na/4Ag/4ZrO 2 /SBA-16 (55% loss in conversion) than with 4Ag/4ZrO 2 /SBA-16 (45% loss in conversion). However, this does not alter the advantageous effect of Na addition because the butadiene yield remained higher throughout the study period for 0.5Na/4Ag/4ZrO 2 /SBA-16. A key finding is that during the reaction, Na limits sintering of Ag particles and promotes selective coking of the acid sites responsible for ethylene and diethyl ether formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Performance of biochar assisted catalysts during hydroprocessing of non-edible vegetable oil: Effect of transition metal source on catalytic activity

Biochar-supported catalysts were developed from nickel (Ni) - and cobalt (Co)- nitrates and hydroxides and tested for the hydrotreatment of carinata oil. Nitrate-based (from water-soluble salts) and hydroxide-based (from water-insoluble salts) catalysts of Ni and Co were prepared via wetness impregnation and aqueous dispersion methods, respectively. The catalysts were characterized using various tools such as, confocal XRF, BET specific surface area analyzer, NH3-TPD, and SEM-EDS. Synchroton method showed nitrate-sourced metals were dispersed mostly in the pores while, the hydroxide-sourced metals were distributed mainly on the catalyst surface. C = C saturation and cracking of triglycerides, decarboxylation, and hydrogenation of aromatic structures appeared to be dominant on the hydroxides of transition metals, hence took place on catalyst surface. Methanation and dehydrogenation (thus aromatization), however, seemed to be a pore phenomenon, catalyzed more over nitrate-based catalysts. A reaction network was proposed based on chemical analysis of upgraded carinata oil and erucic acid model compound. Catalytic cracking followed by hydrotreatment performed better in terms of fuel properties than other approaches in this study.

Biochar catalysts↗
DOE OSTI2022

Dynamic, Adaptive, Systems and Materials: Complex, Simple and Emergent Behaviors

This program has been funded by DoE/BES for twenty years. It has moved into and out of various subjects as it has developed, but it has retained its focus on complexity and complex systems. The project has evolved in the following way: Self-Assembly and Biomimetic Self-Assembly: All self-assembling systems depend upon a minimum of two types of interaction: a repulsion and an attraction. For the familiar molecular systems, attractive interactions are typically hydrogen bonds and electrostatic interactions. Repulsive interactions include steric effects, hydrophobic effects (in biological systems), and charge-charge repulsion. We have expanded this repertoire to include surface interactions, magnetic interactions, and others. I list these systems in the order in which we have explored them: i) A key emphasis in current work is in understanding how the movement of ions in a magnetic field (the Lorentz effect) interacts with catalytic systems. We have demonstrated that an acceleration in rate of reduction of CO 2 to CO can be accomplished by applying an external magnetic field. This acceleration is largely due to the application of the Lorentz effect on mass transport at the catalyst’s surface. ii) We have also extensively explored the influence of electrostatics, as exhibited in self-assembling systems, by tribocharging. iii) Another key system involves surface tension effects; examples include interactions between heavy particles floating at a liquid-air interface, and interacting by changes in surface area; interactions of bubbles and bubble rafts, behaviors of bubble trains in microfluidic networks, and behaviors of microorganisms in constraining environments. iv) This work has intentionally de-emphasized biological systems; but it does include some work on protein-ligand interactions and interactions among microorganisms. v) We have also explored applications of some of these effects, these explorations include bubble rafts as diffraction gratings, exploration of the structures that can be obtained by tribocharging and uses of these structures in exploring nucleation and melting of crystals. vi) Although not a major focus of this work, several other topics have emerged and offer opportunities for future work. These include the behavior of bubble trains and bubble rafts in microfluidic systems. A particularly interesting example is the formation of bubble trains that repeat in the alteration of large and small bubbles according to rules we do not presently understand, but are uniquely large-period oscillating systems. These systems offer a new route into understanding the instabilities of the type represented by oscillations. vii) We have also begun exploratory projects on magnetic levitation (especially to determine molecular density), and information storage (in molecules). Magnetic Levitation: Self-assembling and biomimetic systems require both attraction and repulsion. We have used electrostatics (tribocharging), interfacial free-energies (surface tension and related forces) and others. Potential uses include reconfigurable diffraction gratings and liquid lenses; exploration of mechanisms in tribocharging; tunneling in EGaIn junctions; and bubble trains (especially in micro-fluidic systems). Examples of systems representing these topics is included in the following papers: Complexity: Disks rotating at a water-air interface; Benard-Marangoni effects; Vortex-Crystals from spinning magnetic disks (Marangoni effects); EGaIn Electrode to study quantum tunneling; Self-Assembly of electrostatically-charged metallic spheres (electrets); Dynamically reconfigurable lens; Using computational designs of ligands for enzymes; Electrostatic self-assembly by tribocharging; Monodisperse bubble trains in microchannel systems; Inverted dripping faucet; Flames; Printing of micro-organisms to regenerate the “ink” of printing device; Using micro-organisms to move loads (“microoxen”); Motion of bacterial swarms near surfaces; Making monodisperse particles in microfluidic systems; Coding/decoding of information stored in droplet trains in microfluidic networks; Magnetic levitation; and Information storage. i) Tribocharging. The change in focus of this work on electrets from the fundamentals of charging to applications of these materials in studying self-assembly using electrostatic interactions. ii) Bubbles in Microchannels. The realization that systems of bubbles in microchannels represented a major opportunity to study complexity in a very tractable system, and the development of a semi-quantitative theory of this subject. iii) Flames. The growth of “flames” remains an exploratory subject for the research, although their currently relatively little active work involving it ongoing. iv) Systems with Microorganisms. The removal of work in biological systems from this project. Based on work supported in this program, we now have a significant project on the development of microfluidic tools for studying C. elegans (a nematode), but this work was not appropriate for a program focused on complexity, and we developed separate support for it. (It is, however, an example of successful seeding of a new area by BES.) The work on electrets has gone through a period in which a part of the program was the subject of a MURI; the focus of this work was to develop materials that did not charge electrostatically on friction or contact. The MURI is now over, and the work on dynamic self-assembly (supported by BES) is the major focus. “Flames” has also enjoyed synergistic support, in terms of a project supported by DARPA on flame suppression (in the absence of extinguishing agents, using acoustic and electrostatic interactions). This work was helpful in understanding some of the basics of flames, but is entirely distinct from the BES focus in complexity. A growing interest is in the Lorentz effect. The Lorentz effect is the force exerted on charged particles (electrons, ions, charged molecules) when they move through a perpendicular magnetic field. The Lorentz effect is almost ubiquitous in modern technology: examples of applications include electric motors, dynamos, cathode ray tubes, many batteries, and most systems that control electrical currents with magnetic forces. We have begun to explore the Lorentz effect in electrochemical systems and heterogeneous catalytic systems involving charged organic species and inorganic ions. This work is still at an early stage, but initial studies that Lorentz effects can be large when ions move through magnetic fields, or magnetic fields move in the presence of ions.

36 MATERIALS SCIENCE↗