Search NASA⌕ Search

SEARCH · Search NASA

Results for “combustion synthesis”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Proceedings for the Workshop on Applied Nuclear Data Activities 2024

The Workshop for Applied Nuclear Data Activities (WANDA) is designed to increase communication among nuclear data (ND) users in multidisciplinary federal programs, ND producers, ND funders, and other ND experts. It also presents an opportunity to cross-pollinate ideas as well as introduce ND gaps identified by federal programs to ND experts and ND capabilities to the various federal ND users. WANDA 2024 included five technical sessions, three of which focused on Fusion Energy Sciences (FES)—FES Fusion Neutronics, FES Tritium Production, and FES Material Damage—and two stand-alone sessions—Isotopes and Targetry for Nuclear Data and Uncertainty Quantification. The FES sessions successfully brought new voices to the WANDA discussions, expanding the application space in which nuclear data are critical. FES programs need accurate nuclear data with realistic uncertainty quantification to properly estimate, for example, shielding, activation, tritium production, helium production, structural material integrity, and superconducting magnet operation. This includes a variety of projectile (neutrons, photons, charged particles) and target atoms. One of the action items common to all the FES sessions was a need to perform sensitivity studies to identify the prioritization of nuclear data needs. The Isotopes and Targetry session highlighted the many capabilities available to produce high-quality targets for nuclear data measurements, including 3D printing with spherical powders, combustion synthesis coupled with spin coating & electrospraying, inkjet printing, and isotopic doping. These new methods open doors for more accurate measurement, but it was also stressed that sample characterization following any method of fabrication is of the highest importance to accurately interpret nuclear data measurement results that used that sample. The Uncertainty Quantification (UQ) session was broken into two categories: nuclear data uncertainty quantification and the use of that uncertainty quantification. Thematic to the UQ session was the loss of information when going from nuclear data measurement, to evaluation, to evaluated file, and finally to neutron transport calculations. Current evaluated ND libraries typically only contain covariances, which assume that the probability distributions are Gaussian. Beyond being a simplified assumption for many evaluations, this can lead to negative values on many observables when attempting to sample the covariance. The covariance format, however, is very efficient in that a simple set of linear equations can transform uncertainty from parameters or cross sections to the application of interest. Focused collaboration is needed between nuclear data evaluators and nuclear data users to ensure that needs are being met.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Microwave-assisted dehydrogenation of fossil fuels using iron-based alumina nanocomposites

Hydrogen is mainly produced via steam reforming of methane and gasification of coal, with enormous CO 2 emissions in both cases. Microwave-assisted thermocatalytic decomposition (pyrolysis) is of interest as a method for hydrogen production from fossil fuels with no CO 2 emissions. For successful implementation of this technology, it is necessary to develop decomposition catalysts that are also good microwave absorbers and can be produced from inexpensive materials via a robust synthetic route. Recently, iron-based alumina nanocomposites, fabricated by solution combustion synthesis (SCS), have shown promising microwave-absorbing and catalytic properties in the pyrolysis of plastics. The reported project explored the feasibilities of improving such catalysts and using them for the microwave-assisted pyrolysis of liquid fossil fuels, viz., diesel fuel, gasoline, and crude oil. The research focused on how SCS parameters affect the material properties and pyrolysis performance.

02 PETROLEUM↗
DOE OSTI2026

Single-crystal NMC622 from combustion-assisted solid-state synthesis: Tunable particle size, voltage-dependent stability, and Li-ion diffusion

Cost-effective and scalable synthesis of single-crystal lithium–metal-oxide cathodes with controlled size and morphology remains challenging for advancing high-performance lithium-ion batteries. Here, we demonstrate a solution combustion–assisted solid-state method for producing single-crystal NMC622 with tunable particle size at various lithium stoichiometries. Structural and electronic characteristics were probed using synchrotron-XANES, EXAFS, XRD and XPS, confirming well-defined coordination environments and phase purity up to Li ≈ 1.3. The electrochemical behavior of LixNMC (x = 1.0 and 1.3) single crystals was evaluated across 2.8–4.3 V and 2.8–4.7 V windows to elucidate the effects of lithium content and operating voltage. At 2.8–4.3V, Li1.3NMC exhibits higher initial capacity due to its larger lithium inventory, while Li1.0NMC shows superior long-term retention driven by its larger crystal size and reduced structural distortion. Increasing the cutoff voltage to 4.7 V enhances the initial capacity of both compositions by 17–25%, but long-term capacity retention ultimately converges to values comparable to those at 4.3 V due to voltage-induced degradation, where Li+ diffusion constant remains lying ranging from 10−12 –10−11 cm2s−1. Overall, this study establishes a scalable combustion-assisted route for synthesizing tunable single-crystal NMC622 and highlights the interplay between lithium stoichiometry, particle size, and voltage window in governing cathode stability.

Roy, Subrata C [Jackson State University]↗
DOE OSTI2023

Internal combustion engine as a chemical reactor to produce synthesis gas from hydrocarbon feeds

An internal combustion engine is operated at fuel-rich conditions by adjusting one or more operating parameters such as, for example, a throttle, an ignition timing, a load coupled to the engine, a fuel pressure, power to a supercharger, and power to a preheater to maintain a specified engine speed and a temperature of an exhaust gas. Operating the engine under these conditions allows the engine to function as a reformer producing a synthesis gas comprising hydrogen and carbon monoxide.

Carpenter, III, John Reeves↗
DOE OSTI2021

Combustion in the ZrF 4 -Mg-Si and ZrF 4 -Al-Si systems for preparation of zirconium silicides

The exothermic reactions in the ZrF 4 –Mg-Si and ZrF 4 -Al-Si systems are investigated by a fast temperature recording (thermocouple) technique, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). A quenching method is used to arrest the combustion process and conduct a layer-by-layer analysis of the products by x-ray diffraction (XRD) and electron microscopy. Two seemingly similar reactive systems exhibited considerably different combustion characteristics, composition, and morphology. Based on these investigations, we propose and discuss phase formation mechanisms at the early stages for each system. Three different pathways involving the reaction of ZrF 4 with other reagents and the Mg 2 Si intermediate are identified to occur in the ZrF 4 –Mg-Si system. Contrary to the complex mechanism in the ZrF 4 –Mg-Si system, the early stage of the combustion process for the ZrF 4 -Al-Si system involves the interaction of ZrF 4 with Al-Si eutectic melt. The exothermic reaction between reduced solid Zr and Si melt is the primary heat-generating step for both systems in spite of substantial differences in the early stages of the reactions. The silicon content in the reactive mixtures governs the phase composition of products. The ZrSi 2 phase, with a high growth rate, forms first on the Zr particle surfaces and then grows by a reactive diffusion mechanism. The ZrSi 2+ Zr reaction produces silicon-lean phases (e.g., ZrSi) when the silicon supply is limited. The combustion temperature also has a considerable influence on the phase compositions of the products. High combustion temperature in the ZrF 4 +2Mg+Si mixture enables the formation of multiphase products (α-ZrSi and β-ZrSi), whereas the relatively lower temperatures in the 3ZrF 4 +4Al+3Si mixture yields a single-phase α-ZrSi. As a result, lower combustion temperatures also make the ZrF 4 -Al-Si system more advantageous for the preparation of zirconium silicides.

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

Combustion-assisted ink-jet printing of nuclear targets

Advances in target fabrication are critical to high-precision measurements in nuclear physics. This work details the preparation of patterned CeO 2 and ThO 2 architectures and thin-film targets via ink-jet deposition of combustible solutions. The produced targets were characterized by scanning electron microscopy (SEM), and by alpha-particle spectroscopy for radioactive targets to determine densities. Ink jet printing of the targets, used both ethanol and 2-methoxyethanol as solvents, with cerium or thorium nitrate as the oxidizer and acetylacetone as the fuel. Additionally, we found that the distance between each droplet dispersion (step size) played the most significant role in determining the final pattern uniformity and thickness. A 50 μm step size leads to relatively thick targets with a density of 350 μg/cm 2 . Significant overlap in droplet sizes leads to a heterogeneous target with an undesirable cracked surface structure. In contrast, 150 μm spacing yields thinner (20 μg/cm 2 ) patterned structures with excellent surface coverage. This method of Ink-jet printing provides a straightforward, scalable, and high-efficiency pathway to prepare custom made, high-quality targets for nuclear physics experiments.

CeO2↗
DOE OSTI2019

Rotating Detonation Combustion for Gas Turbines: Modeling and System Synthesis to Exceed 65% Efficiency Goal (Phase II)

As of May 2019, all RDE test hardware and test operations were completed for this program. Over 700 hot fire tests were conducted at 4 facilities with 7 RDE assemblies, with the data available for future analysis. In particular, measured static and dynamic pressure and computational fluid dynamics (CFD) provided basis for pressure gain combustion (PGC) analysis of the Engineering Scale RDE. It was demonstrated via measurements and CFD that a carefully designed diffuser can recover some total pressure of the highly oscillatory RDE exhaust. In general, the isolator/injector is largest contributor of pressure losses; however a low loss design was demonstrated that improves significantly on previous natural-gas/air RDEs. Also, a tailored injector and mixing technique was demonstrated that allowed NG-air RDE operation with overall equivalence ratio of less than 0.6. CFD models by AR, the UofM and Purdue University were extensively used throughout the program to refine diffuser design for improved pressure recovery, to simulate injection and mixing, to estimate turbine interaction, to estimate combustor pressure gain anchored with test data and to provide input to other design and analytical tasks. CFD analyses were completed for many of the configurations tested at Purdue with the 13.4” RDE including the shark fin and low area ratio isolators. Results were compared favorably to available hot fire test particle image velocimetry (PIV) measurements and wave speeds. The results of these CFD analyses suggest a modest pressure gain of 33% with a sufficiently low area ratio isolator. A thermodynamic power plant system model was set up which utilizes an RDE combustor. The performance of the RDE combustor module was scaled based on measurements from the Engineering Scale RDE tests with low loss injector and tailored fuel flow. This combined model indicates potential for significant plant efficiency improvement. The successful tailored fuel injection test result with lower than .6 equivalence ratio has implication that a power plant can use a RDE combustor configuration where all the air flows through the combustion zone thereby not requiring a bypass mixer. In this configuration, the results of the natural gas combined cycle (NGCC) plant system indicate net efficiency of 66.4%.

02 PETROLEUM↗
DOE OSTI2025

Fabrication, oxidation, and combustion of nanoscale magnesium diboride and tetraboride

The difficult ignition of boron decreases the combustion efficiency of boron-loaded, fuel-rich propellants. One approach to solving this problem involves the use of magnesium diboride (MgB2), which ignites easier than boron. Magnesium tetraboride (MgB4) offers greater energy density owing to its higher boron content. However, the effect of B/Mg ratio on the ignition and combustion is unknown. Additionally, while nanoscale MgB₂ particles and quasi-2D structures were recently recognized as promising energetic additives, the oxidation and combustion properties of nanoscale MgB₄ have not been explored. The objectives of the present work included synthesis, purification, and high-energy ball milling of MgB2 and MgB4 powders as well as investigation of their thermal decomposition, oxidation, and combustion. The MgB2 and MgB4 powders were fabricated by combustion synthesis in the chemical oven mode and by heating Mg/B mixtures in a tube furnace. The latter method was superior in the synthesis of MgB4. Oxide impurities in the synthesized powders were removed by acid leaching. Nanoscale powders were obtained by high-energy ball milling. Thermal decomposition and oxidation of the obtained MgB₂ and MgB₄ powders were investigated by conducting non-isothermal thermogravimetric analysis (TGA) at temperatures up to 1550 °C in argon and oxygen flows. Combustion of B, MgB₂, and MgB₄ powders with oxygen at atmospheric pressure was studied in a windowed chamber using laser ignition and high-speed video recording. The TGA has shown multi-step decomposition of both magnesium borides in an argon environment. The maximum oxidation rate of MgB4 in oxygen was observed at a much lower temperature than in the case of MgB2. In the combustion experiments, both magnesium borides burned much faster than submicron boron. Ball milling of the borides further increased their burning rates. It has been concluded that nanoscale magnesium tetraboride is a promising ingredient for fuel-rich propellants owing to its high energy density, efficient oxidation, and rapid combustion.

Molina, Andre [The University of Texas at El Paso]↗
DOE OSTI2025

Fabrication and characterization of nanoscale magnesium diboride and tetraboride for propulsion and hydrogen storage applications

Abstract: Boron-loaded propellants have the potential to dramatically increase the performance of solid fuel ramjets, ducted rockets, and hybrid rocket engines. However, difficult ignition of boron decreases the combustion efficiency of these propellants. One approach to solving this problem involves the use of magnesium diboride, MgB2, which ignites easier than boron. Magnesium tetraboride, MgB4, potentially offers greater energetic performance as B has a higher energy density than Mg. However, the effect of the higher boron/metal ratio on the ignition and combustion is unclear. Nanoscale MgB2 particles and quasi 2D structures are promising propellant ingredients, but the oxidation and combustion properties of nanoscale MgB4 remain unknown. Nanoscale magnesium borides are also of interest as precursors for the synthesis of magnesium borohydride, Mg(BH4)2, a promising hydrogen storage material, but hydrogenation of MgB4 has not been studied yet. The objectives of the present work included synthesis, purification, and high-energy ball milling of MgB2 and MgB4 powders as well as investigation of their hydrogen uptake, thermal decomposition, oxidation, and combustion. The powders were fabricated by combustion synthesis and by heating in a tube furnace. The latter method was superior in the synthesis of MgB4. Oxide impurities in the synthesized powders were removed by acid leaching. Nanoscale powders were obtained by ball-mill exfoliation. The hydrogen intake of the obtained magnesium borides was examined at 700 bar and 300 ℃ and did not reveal any advantage of MgB4 over MgB2. Their thermal decomposition and oxidation were investigated with thermogravimetric analysis (TGA), while their combustion was studied using laser ignition and high-speed video recording. TGA has confirmed prior observations of multistep decomposition of magnesium borides, where each step involves formation of a boride with a higher B/Mg ratio and evaporation of formed magnesium. The oxidation rates of the borides are much higher than that of boron at temperatures over 1200 °C for MgB2 and over 900 °C for MgB4. The burning rates of non-milled MgB₂ and MgB₄ powders were much higher than for the used submicron boron. Milling the MgB₂ and MgB₄ powders further increased their burning rates. The milled MgB4 burned 7.5 times faster than submicron boron.

Combustion of metals, Solid fuels, Propellants, Hy↗
DOE OSTI2023

Polynitrogen High Energy Density Materials Synthesized by Nonequilibrium Plasma

Metal pentazolate compounds that contain 5-nitrogen singly charged anion rings are an interesting class of materials from a thermodynamics perspective. These compounds are believed to be equilibrium phases only at extremely high pressures, and thus, they constitute exotic states of matter at ambient pressure and temperature. Moreover, the energy released by these pentazolate compounds upon relaxation to the equilibrium state at ambient conditions is in the range 1 to 10 MJ per kg, rivaling that of combustion reactions. The synthesis of pentazolates is not an easy task, and there are only two known methods, each of which has significant challenges. Here, the development of new scalable synthesis routes could enable the production of these exotic materials in sufficient quantity to explore their properties more widely beyond the context of explosives and propellants. In this Perspective, it is argued that nonequilibrium plasma is a promising reaction medium for the synthesis of metal pentazolate compounds, for example from the corresponding metal azide and N 2 gas activated by the discharge at low background temperature.

Chemical reactions↗
DOE OSTI2024

Scanning Mobility Particle Sizer (SMPS) Instrument Handbook

The Model 3936 Scanning Mobility Particle Spectrometer (SMPS) measures the size distribution of aerosols ranging from 10 nm up to 1000 nm. The SMPS uses a bipolar aerosol charger to keep particles within a known charge distribution. Charged particles are classified according to their electrical mobility, using a long-column differential mobility analyzer (DMA). Particle concentration is measured with a condensation particle counter (CPC). The SMPS is well-suited for applications including: nanoparticle research, atmospheric aerosol studies, pollution studies, smog chamber evaluations, engine exhaust and combustion studies, materials synthesis, filter efficiency testing, nucleation/condensation studies, and rapidly changing aerosol systems.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Fluidized-Bed Gasification of Coal-Biomass-Plastics for Hydrogen Production

Coal is one of the most abundant fossil energy resources in the United States and in the world. The recoverable reserves in the United States are estimated to be about 252 billion tons – more than 350 years of supply at current rates of usage. However, the share of coal in total primary energy consumption in the US has been declining over the years. The decline of coal is mainly attributed to cheap natural gas and precipitous declines in the cost of electricity production from renewable technologies such as wind and solar. Coal can potentially be used if it is coupled with carbon-neutral feedstock such as biomass-agricultural residues, forest biomass, and forest residues. Co-gasification of coal and biomass can become a negative carbon emission technology if the carbon dioxide (CO 2 ) is captured and sequestered. Although the biomass gasification process has a lot of similarities to coal gasification, the large-scale adaptation of power production sourced from biomass has not come to fruition. The main reason is that the power production from biomass is still expensive when compared with natural gas or coal power technologies. To address the feedstock cost, one approach is to use low-cost feedstocks, such as municipal solid wastes (MSW) or plastics, for gasification. Gasification involves the partial oxidation of coal and/or biomass feedstocks to produce a combustible fuel called synthesis gas (syngas) which is composed of carbon monoxide (CO), hydrogen (H 2 ), CO 2 , methane (CH 4 ), nitrogen (N 2 ), water (H 2 O), and other compounds that might be considered as contaminants. Raw syngas from gasification must go through multiple steps to produce high-purity hydrogen. The specific steps depend upon the quality (gas composition, contaminants, and their concentration) and condition (pressure and temperature) of syngas. The long-term goal of the project was to utilize coal and plastics together with biomass to produce energy and fuels using a gasification platform while reducing greenhouse gas emissions. The main objective of this research was to examine gasification performance in a laboratory-scale fluidized-bed gasifier for hydrogen production. The specific objectives of the research were to: (i) study coal-plastic-biomass mixture flowability for consistent feeding in the gasifier; (ii) understand the gasification behavior of the mixture in steam and oxygen environments; (iii) perform thermal property characterization of ash and slag from the mixture feedstock and refractory-ash interface of the mixture under gasification conditions; and (iv) develop process models to determine the technology needed for syngas cleanup and contaminants. The study found that there was no apparent segregation when biomass, coal, and waste plastics were mixed together during feeding. Although there were differences in hydrogen production when individual feedstock were fed, the hydrogen concentration remained almost constant with various blends. Therefore, blending waste plastics with biomass and coal, which are all abundant, is a better approach for energy production. Results of the techno-economic analysis suggested that integration of advanced gasification (GTI’s R-GAS™) and syngas cleanup and conditioning technologies (RTI’s WDP and AFWGS) for clean hydrogen production resulted in substantial benefits, including significant capital cost and operating cost reductions. Advanced technologies resulted in 16% reduction in the hydrogen production cost (COH) from 2.94 $\$$/kg to 2.47 $\$$/g, with further scope for optimization and cost reduction. These advanced technologies also result in lower emissions, and improved energy efficiency.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2025

A Mössbauer Spectroscopy Investigation of Nickel‐Zinc Ferrites Synthesized by a Self‐Combustion Method for Soft Magnetic Core Applications

Soft ferrites are materials of interest for magnetic cores, as used for wireless charging transformers. Their low permeabilities, high resistivity, and magnetic polarization make them interesting for high-power electric vehicle charging and drive systems. The nickel-zinc-doped ferrites are of particular interest; however, the compositional space is quite large with respect to dopant concentrations, stoichiometric ratios and synthesis technique. Nickel-zinc spinel ferrites with varying nickel-zinc ratios prepared by a self-combustion reaction followed by heat treatment exhibit good crystallinity, and their low-temperature Mössbauer spectra show local magnetism and site occupation in agreement with materials prepared by solid-state reaction. Thus, the combustion synthesis method offers a facile tunability of compositions, which, combined with the possibility of rapid characterization of atomic-scale magnetism by Mössbauer spectroscopy, enables advances in the compositional and processing space at a fast pace. Low-temperature Mössbauer spectroscopy data for samples with increasing nickel content reveals a systematic increase in average hyperfine field (2.8 T/Ni) and decrease in average isomer shift (−0.036 mm/s/Ni) that can determine the nickel/zinc content, even in the absence of applied magnetic field data. Furthermore, a gradual evolution of color is also observed with increasing nickel content, albeit trends in color depend on sintering conditions.

Mössbauer spectroscopy↗
DOE OSTI2019

Environmentally benign synthesis of a PGM-free catalyst for low temperature CO oxidation

Dopants enhance the catalytic properties of ceria. However, conventional techniques for synthesizing doped ceria have limitations in terms of structural homogeneity, surface area, and catalytic activity of the resulting oxide. Use of toxic and corrosive chemicals presents further challenges. The sol-gel method described in this work provides a facile approach for incorporating high concentrations of dopants in a uniform, high surface area structure, yielding excellent catalytic activity. Addition of polyvinylpyrrolidone (PVP) complexing agent prevents the segregation of cerium and dopant atoms during synthesis. Surface areas up to 179 m 2 /g are achieved, which represents a substantial improvement over doped ceria produced through coprecipitation, solution combustion, or melt-synthesis methods. The resulting powders exhibit dramatically improved CO oxidation activity (T 90 = 132 °C for 3.2 wt% Cu-CeO 2 compared to 274 °C for a 2 wt% Pt-Al 2 O 3 reference catalyst). First principles calculations suggest a Mars Van Krevelen mechanism, which is facilitated by dopants causing oxygen vacancies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗