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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

SiC compatibility

SiC is a relatively chemically stable ceramic that has potential use in the extreme environments present in nuclear reactors. Reactions with high temperature steam, He, hydrothermal, molten salts, and liquid metals are some of the possible environments that SiC could be exposed to. While it is very stable in air, aqueous environments and very low oxygen partial pressures can lead to SiC recession. Generally, SiC does not react with the FliNaK or FliBe molten salts, or liquid metals, however contaminants in these working fluids leached from other materials can cause reaction layers to occur. Most of these systems require additional testing under neutron irradiation to determine if there are any combined effects.

Mouche, Peter↗
DOE OSTI2023

Chemical Recycling Processes of Waste Polyethylene Terephthalate Using Solid Catalysts

Polyethylene terephthalate (PET) is a non-degradable single-use plastic and a major component of plastic waste in landfills. Chemical recycling is one of the most widely adopted methods to transform post-consumer PET into PET's building block chemicals. Non-catalytic depolymerization of PET is very slow and requires high temperatures and/or pressures. Recent advancements in the field of material science and catalysis have delivered several innovative strategies to promote PET depolymerization under mild reaction conditions. Particularly, heterogeneous catalysts assisted depolymerization of post-consumer PET to monomers and other value-added chemicals is the most industrially compatible method. Here, this review includes current progresses on the heterogeneously catalyzed chemical recycling of PET. It describes four key pathways for PET depolymerization including, glycolysis, pyrolysis, alcoholysis, and reductive depolymerization. The catalyst function, active sites and structure-activity correlations are briefly outlined in each section. An outlook for future development is also presented.

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

NCAP: Noncanonical Amino Acid Parameterization Software for CHARMM Potentials

Noncanonical Amino Acids (NCAAs) provide numerous avenues for introduction of novel functionality to peptides and proteins. NCAAs can be incorporated through solid phase synthesis or genetic code expansion in conjugation with heterologous expression of the encoded protein modification. Due to the difficulty of synthesis, wide chemical space and lack of empirically resolved structures modeling the effects of NCAA mutation is critical for rational protein design. To evaluate the structural and functional perturbations NCAAs introduce we utilize molecular potentials that describe the forces in protein structure. Most potentials such as CHARMM are designed to model canonical residues but can be parameterized in include novel NCAAs. Here, in this work, we introduce NCAP a software package to generate CHARMM compatible parameters from quantum chemical calculation. Unlike currently available tools NCAP is designed to recognize NCAA structure and automatically bridge the gap between DFT calculations and potential parameters. For our software we discuss workflow, validation against canonical parameter sets and comparison to published NCAA-protein structures.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1994

Martian carbonates in ALH 84001: Textural, elemental, and stable isotopic compositional evidence on their formation

Martian orthopyroxenite ALH 84001 is unusual compared to other martian meteorites in its abundance of Mg-Fe-Ca carbonites. Becasue textural evidence indicates that these carbonates are undoubtedly of martian origin, we have undertaken stable isotopic studies to elucidate their origin by evaluating whether they represent primordial martian C that was outgassing from the mantle of Mars, or volatile additions to the ALH 84001 protolith that equilibrated with the martian atmosphere. If precipitation occurred in a closed system then the isotopic results are compatible with the observed chemical zonation. A unique temperature of formation can be calculated using the difference in C-13 and O-18 between the Fe and Mg carbonates, assuming that precipitation occurred at a constant temperature. Precipitation of approximately one-half of the CO2 reservoir at 320 C can account for the observed values, with the original CO2 reservoir having a delta C-13 of approximately 45% and delta O-18 of approximately 22%. If carbonate precipitated in equilibrium with a large isotopically homogeneous CO2 reservoir (open system), isotopic differences must be attributed to a change in temperature of at least several hundreds of degrees. This temperature change is compatible with a calculated range of temperatures based on carbonate geothermometry. Clearly, carbonate in ALH 84001 is in delta O-18 disequilibrium with orthopyroxene groundmass. Most likely, the carbonate precipitated from a fluid that equilibrated with the martian atmosphere. The deposits or fluids in equilibrium with these deposits were remobilized in the crust producing the carbonate in ALH 84001. This observation establishes a link for the first time between the atmospheric and lithospheric C and O pools that reside on Mars.

Romanek, C. S.↗
DOE OSTI2026

Solvent selection for a biomass-to-bioproduct pipeline through integrated reductive catalytic fractionation and microbial funneling

The growing significance of lignin-first biorefineries, which focus on upgrading the aromatics resulting from lignin depolymerization, presents opportunities for bioproduct synthesis using microbial strains capable of funneling a diverse array of phenolics into a single commodity chemical. In this study, we evaluated a biomass-to-bioproduct pipeline involving the reductive catalytic fractionation (RCF) of poplar biomass followed by biological funneling with a Novosphingobium aromaticivorans strain that produces 2-pyrone-4,6-dicarboxylic acid (PDC), a potential bioplastic precursor. Considering the impact of solvent on RCF reactor operating pressure, and the potential inhibitory effects of solvent on downstream microbial funneling, we performed an analysis of six pure solvents, namely methanol, ethanol, isopropanol, isobutanol, 1,4-dioxane and ethylene glycol, and different variations of their aqueous mixtures comprising 5 to 50 vol% water. For each pure solvent and solvent/water system, we measured phenolic monomer yields in the RCF process and PDC yields from the phenolic monomers. We then developed correlation models that relate phenolic monomer yields from RCF-derived samples to Hansen solubility parameters to determine solvent descriptors that contribute to high yields. Furthermore, we developed an integrated biorefinery system to estimate the minimum selling price (MSP) of PDC and the associated carbon footprint to identify solvent systems with better costs and sustainability metrics. These analyses resulted in the 50 vol% methanol/water system being identified as optimal because it reduces RCF reactor pressure and is compatible with microbial funneling with N. aromaticivorans. This solvent system produced 63 g PDC per kg biomass (264 g PDC per kg lignin) from 85 g phenolic monomers per kg biomass at a reduced reactor pressure of 48 bar (reduced by 26% compared to our previous poplar-to-PDC pipeline). The MSP for this system is $\$$13.98 per kg of purified PDC (carbon footprint of 1.47 kg CO 2 e per kg), which is about 24% lower than a previously described poplar-to-PDC pipeline and 46% lower than a lignin-to-PDC pipeline that used pure methanol as the solvent. The results from this study illustrate improvements that can be made in lignocellulosic biorefineries that are compatible with the hybrid chemical and biological processes needed to gain value from lignin.

Sripada, Sarada [Great Lakes Bioenergy Research Ce↗
DOE OSTI2022

Lignin-based jet fuel and its blending effect with conventional jet fuel

Sustainable aviation fuels (SAFs) must demonstrate specific physical and chemical properties as well as material compatibility (i.e., seal swell) to be used as an aviation turbine fuel. Several alternative jet fuels incorporated in ASTM D7566 are comprised mainly of n/iso-alkanes and can only be blended up to 50 vol% due to material compatibility and density issues. Prior work illustrated the ability of cycloalkanes to replace aromatics’s role in material compatibility. Here, we report the first archival documentation of a feedstock and chemical process to yield a product composition able to complement existing SAF ASTM D7566 annexes. A lignin-based jet fuel (LJF) blend components is generated and composed of mostly C7-C18 mono, di, and tri-cycloalkanes. The neat LJF was blended with conventional jet fuel at 10 vol% (LJF blend) to simulate an ASTM “Fast Track” evaluation process. Fuel properties that are critical to engine operability (ATSM D4054 Tier 3 & 4) were either predicted or experimental tested based on the volume availability. All LJF blend’s critical properties fall within the experience range of conventional jet fuel, with o-ring swelling exceeding the typical range of conventional fuels. Here, these results in total support the potential use of this LJF pathway to complement other SAF pathways and achieve 100% drop-in SAF.

09 BIOMASS FUELS↗
DOE OSTI2021

Upgrade of the Materials Analysis Particle Probe (MAPP-U) to decipher the impact of lithium-based surfaces on NSTX-U plasma behavior

Understanding the plasma wall interaction (PWI) remains a critical issue for the feasibility of thermonuclear magnetic fusion energy solutions. Key issues with PWI mechanisms in fusion tokamak reactors include: evolution of surface chemistry and its role on hydrogen retention. In particular how low-Z coatings such as lithium can impact the behavior of plasma at the edge and in the core. PMI (plasma-material interactions) are particularly important for strategies that involve low-recycling regimes and the use of lithium PFS (plasma-facing surfaces) to attain them, as in the case of NSTX-U. Recent reports have indicated the importance of access to the evolving plasma-facing surface during and in-between plasma discharges. Changes in surface chemistry and morphology due to ion bombardment and the difficulty of diagnosing plasma-facing surfaces, especially reactive surfaces, complicate the development of a predictive understanding of the wall and its interaction with the plasma. Consequently, this impairs the ability to design advanced PFC materials for future plasma-burning fusion reactors and appropriate PMI code validation. The Materials Analysis Particle Probe (MAPP) is an established and on-going PMI probe diagnostic system compatible with the highly chemically reactive system of lithium and boron coatings adopted by the NSTX-U research program. MAPP is the first PMI diagnostic to capture the surface physics and chemistry in-vacuo in a fusion tokamak system and correlate this data to controlled plasma shots. Currently MAPP captures this information at a fixed radial location at the NSTX-U outboard divertor region. The MAPP diagnostic has enabled understanding of the near-surface and surface chemistry of complex evolving lithiated and borated carbon-based PFC surfaces retention and transport of hydrogen. Coupled to atomistic simulations in collaboration with P. Krstic of Stony Brook U. MAPP has been very successful in achieving high-impact scientific research in its current grant period evidenced by two invited review articles and over 20 peer-reviewed manuscripts and over 40 contributed and invited presentations at both national and international conferences.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1973

Apollo experience report: Potable water system

A description of the design and function of the Apollo potable water system is presented. The command module potable water is supplied as a byproduct of the fuel cells. The cells, located in the service module, function primarily to supply electrical energy to the spacecraft. The source of the lunar module potable water is three tanks, which are filled before lift-off. The technique of supplying the water in each of these cases and the problems associated with materials compatibility are described. The chemical and microbiological quality of the water is reviewed, as are efforts to maintain the water in a microbially safe condition for drinking and food mixing.

Sauer, R. L.↗
NASA NTRS1979

Silicon material task - Low cost solar array project /JPL/DOE/

The paper describes the silicon material task of the low-cost solar array project, which has the objective of establishing a silicon production capability equivalent to 500 mW per year at a price less than 10 dollars/kg (1975 dollars) in 1986. The task program is divided into four phases: technical feasibility, scale-up studies (the present phase), experimental process system development units, and implementation of large-scale production plants, and it involves the development of processes for two groups of materials, that is, semiconductor grade and solar cell grade. In addition, the effects of impurities on solar cell performance are being investigated. Attention is given to problem areas of the task program, such as environmental protection, material compatibility between the reacting chemicals and materials of construction of the equipment, and waste disposal.

Lutwack, R.↗
NASA NTRS2001

Degradation Of Environmental Barrier Coatings (EBC) Due To Chemical and Thermal Expansion Incompatibility

Current environmental barrier coatings (EBCs) consist of multiple layers, with each layer having unique properties to meet the various requirements for successful EBCs. As a result, chemical and thermal expansion compatibility between layers becomes an important issue to maintaining durability. Key constituents in current EBCs are mullite (3Al2O3-2SiO2), BSAS (BaO(1-x)-SrO(x)-Al2O3-2SiO2), and YSZ (ZrO2-8 wt.% Y2O3). The mullite-BSAS combination appears benign although significant diffusion occurs. Mullite-YSZ and BSAS-YSZ combinations do not react up to 1500 C. Thermally grown SiO2- BSAS and mullite-BSAS-YSZ combinations are most detrimental, forming low melting glasses. Thermal expansion mismatch between YSZ and mullite or BSAS causes severe cracking and delamination.

Lee, Kang N.↗
NASA NTRS2006

Explosive Event in MON-3 Oxidizer System Resulting from Pressure Transducer Failure

In 2003, a Druck(Registered Trademark) pressure transducer failed catastrophically in a test system circulating nitrogen tetroxide at NASA Johnson Space Center White Sands Test Facility. The cause of the explosion was not immediately obvious since the wetted areas of the pressure transducer were constructed of materials compatible with nitrogen tetroxide. Chemical analysis of the resulting residue and a materials analysis of the diaphragm and its weld zones were used to determine the chain of events that led to the catastrophic failure. Due to excessive dynamic pressure loading in the test system, the diaphragm in the pressure transducer suffered cyclic failure and allowed the silicon oil located behind the isolation diaphragm to mix with the nitrogen tetroxide. The reaction between these two chemicals formed a combination of 2,4-di and 2,4,6-trinitrophenol, which are shock sensitive explosives that caused the failure of the pressure transducer. Further research indicated numerous manufacturers offer similar pressure transducers with silicone oil separated from the test fluid by a thin stainless steel isolation diaphragm. Caution must be exercised when purchasing a pressure transducer for a particular system to avoid costly failures and test system contamination.

Baker, David L.↗
NASA NTRS2004

Fabrication of Channels for Nanobiotechnological Devices

A method, now undergoing development, of forming nanochannels in planar substrates is intended to enable the fabrication of advanced fluidic devices that could be integrated with complementary metal oxide semiconductor (CMOS) electronic circuits. Such integral combinations of fluidic and electronic components ("laboratory-on-a-chip" devices) could be used, for example, to detect individual molecules of deoxyribonucleic acid (DNA) and proteins. The width of a channel in such a device would be chosen so that molecules of the species of interest would move along the channel in single file. In this method, the fabrication of channels includes the use of such CMOS-compatible processes as chemical-mechanical polishing and oxide deposition. The layout of the channels in the substrate plane is determined by a single photolithographic process, but it is not a nanoscale lithographic process, and this process is not relied upon to define the thickness and width of the channels. Stating it from a slightly different perspective, unlike in the prior fabrication of electronic and fluidic devices involving the use of lithography to define microscale features, this process does not include the use of lithography to define nanoscale features. It is this aspect of the method that enables simplification of the process and, hence, a decrease in cost.

Lee, Choonsup↗
NASA NTRS2002

High-Performance, Space-Storable, Bi-Propellant Program Status

Bipropellant propulsion systems currently represent the largest bus subsystem for many missions. These missions range from low Earth orbit satellite to geosynchronous communications and planetary exploration. The payoff of high performance bipropellant systems is illustrated by the fact that Aerojet Redmond has qualified a commercial NTO/MMH engine based on the high Isp technology recently delivered by this program. They are now qualifying a NTO/hydrazine version of this engine. The advanced rhenium thrust chambers recently provided by this program have raised the performance of earth storable propellants from 315 sec to 328 sec of specific impulse. The recently introduced rhenium technology is the first new technology introduced to satellite propulsion in 30 years. Typically, the lead time required to develop and qualify new chemical thruster technology is not compatible with program development schedules. These technology development programs must be supported by a long term, Base R&T Program, if the technology s to be matured. This technology program then addresses the need for high performance, storable, on-board chemical propulsion for planetary rendezvous and descent/ascent. The primary NASA customer for this technology is Space Science, which identifies this need for such programs as Mars Surface Return, Titan Explorer, Neptune Orbiter, and Europa Lander. High performance (390 sec) chemical propulsion is estimated to add 105% payload to the Mars Sample Return mission or alternatively reduce the launch mass by 33%. In many cases, the use of existing (flight heritage) propellant technology is accommodated by reducing mission objectives and/or increasing enroute travel times sacrificing the science value per unit cost of the program. Therefore, a high performance storable thruster utilizing fluorinated oxidizers with hydrazine is being developed.

Schneider, Steven J.↗
NASA NTRS1976

A versatile system for biological and soil chemical tests on a planetary landing craft. I - Scientific objectives

We describe an approach for the remote detection and characterization of life in planetary soil samples. A mass spectrometer is used as the central sensor to monitor changes in the gas phase in eleven test cells filled with soil. Many biological assays, ranging from general 'in situ' assays to specific metabolic processes (such as photosynthesis, respiration, denitrification, etc.) can be performed by appropriate additions to the test cell via attached preloaded injector capsules. The system is also compatible with a number of chemical assays such as the analysis of atmospheric composition (both chemical and isotopic), the status of soil water, and the determination of compounds of carbon, nitrogen and sulfur in the soil.

Radmer, R. J.↗
NASA NTRS1989

Theoretical analysis of compatibility of several reinforcement materials with NiAl and FeAl matrices

Several potential reinforcement materials were assessed for their chemical, coefficient of thermal expansion (CTE), and mechanical compatibility with the intermetallic matrices based on NiAl and FeAl. Among the ceramic reinforcement materials, Al2O3, TiC, and TiB2, appear to be the optimum choices for NiAl and FeAl matrices. However, the problem of CTE mismatch with the matrix needs to be solved for these three reinforcement materials. Beryllium-rich intermetallic compounds can be considered as potential reinforcement materials provided suitable reaction barrier coatings can be developed for these. Based on preliminary thermodynamic calculations, Sc2O3 and TiC appear to be suitable as reaction barrier coatings for the beryllides. Several reaction barrier coatings are also suggested for the currently available SiC fibers.

Misra, Ajay K.↗
DOE OSTI2026

Impact of Salt Chemistry and Interlayer Architecture on Solid Electrolyte Interphase Composition and Performance

Reversible lithium metal anodes require interphases that are chemically stable, mechanically robust, and compatible with scalable processing. Here, we use slot-die-coated, salt-rich PEO interlayers to design SEI nanolayers on Cu current collectors and isolate how salt anion chemistry controls interphase composition and lithium plating/stripping behavior in architectures relevant to Li plating and anode-free cells. Mesoscale modeling shows that dendrite initiation at SEI defects is governed by a tradeoff among interphase thickness, ionic conductivity, and stiffness through defect-driven current focusing, motivating controlled formation from thin precursor layers. Using UHV-transferred XPS and ToF-SIMS depth profiling after controlled Li deposition, we find that fluorinated sulfonylimide salts (LiTFSI, LiFSI) form mixed inorganic/organic interphases containing LiF and PEO-derived alkoxides, with LiFSI producing a more LiF-dominant Li-facing surface than LiTFSI under identical conditions. In contrast, LiNO 3 -containing interlayers yield a comparatively thick nitrate-derived interphase that reduces upon Li contact to an N-rich inorganic layer (Li–N/N 3− , LiN x O y ). In Cu| |Li cells, these designed interlayers reduce interfacial resistance and improve Coulombic efficiency (CE) and critical current density (CCD) relative to uncoated controls, with LiFSI- and LiNO 3 -based interlayers providing the highest CE/CCD. Overall, the results demonstrate a manufacturing-relevant approach to engineer SEI nanolayers by salt chemistry, providing pathways to improve reversible lithium metal anodes while reducing reliance on LiTFSI.

anion chemistry↗
DOE OSTI2022

Number of surface sites and turnover frequencies for oxide catalysts

Unlike for metal catalysts where selective chemisorption probes (H 2 , O 2 , CO and N 2 O) have been successfully applied to count the number of active surface sites and allow determination of TOF values, the analogous situation for oxide catalysts has developed very slowly. The reason for the sluggish development of selective chemisorption probes for oxides is that the same chemisorption probes that work well with metals aren’t compatible with oxides since these chemical probes weakly adsorb on oxides. Methanol, however, is a very reactive molecule that has been found to readily chemisorb on oxides and allows for quantitative determination of the number of active surface sites (Ns). Here, in this mini-review, the determination of the number of active sites by methanol chemisorption is reviewed with examples for pure oxides (one-component oxides), supported oxides (submonolayer, monolayer and above monolayer) and bulk mixed oxides (surface enriched oxide present in submonolayer, monolayer and in excess of monolayer coverages).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗