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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Estimates of Optimal Operating Conditions for Hydrogen-Oxygen Cesium-Seeded Magnetohydrodynamic Power Generator

The value of percent seed, oxygen to fuel ratio, combustion pressure, Mach number, and magnetic field strength which maximize either the electrical conductivity or power density at the entrance of an MHD power generator was obtained. The working fluid is the combustion product of H2 and O2 seeded with CsOH. The ideal theoretical segmented Faraday generator along with an empirical form found from correlating the data of many experimenters working with generators of different sizes, electrode configurations, and working fluids, are investigated. The conductivity and power densities optimize at a seed fraction of 3.5 mole percent and an oxygen to hydrogen weight ratio of 7.5. The optimum values of combustion pressure and Mach number depend on the operating magnetic field strength.

Smith, J. M.↗
NASA NTRS2008

MISSE Results Used for RF Plasma Ground Testing-To-Space-Exposure Correlation for Coated Kapton

The ability to predict the durability of materials in the low Earth orbit (LEO) environment by exposing them in ground-based facilities is important because one can achieve test results sooner, expose more types of materials, and do it much more cost effectively than to test them in flight. However, flight experiments to determine the durability of groups or classes of materials that behave similarly are needed in order to provide correlations of how much time in ground-based facilities represents certain durations in LEO for the material type of interest. An experiment was designed and flown on the Materials International Space Station Experiment (MISSE) 2 (3.95 yr in LEO) and MISSE 4 (1.04 yr in LEO) in order to develop this type of correlation between ground-based RF plasma exposure and LEO exposure for coated Kapton. The experiment consisted of a sample of Kapton H (DuPont) polyimide coated with 1300 of silicon dioxide by Sheldahl, Inc. The samples were exposed to atomic oxygen in a radio frequency (RF) generated atomic oxygen plasma. Mass change was measured for the samples and then the same samples were exposed in flight on MISSE and the mass change was again recorded post-flight. After documentation, the samples were exposed again in the ground-based RF plasma in order to determine if the erosion would be the same as it had been in the same facility pre-flight which would indicate whether or not the sample had been damaged during flight and if the defects on the surface were those that were there preflight. The slopes of the mass change versus fluence plots were then used to develop a correlation factor that can be used to help predict the durability of coated Kapton in ground-based isotropic atomic oxygen plasma systems. This paper describes the experiment and presents the correlation factor results.

Miller, Sharon K. R.↗
DOE OSTI2019

Signatures of Biologically Driven Hemicellulose Modification Quantified by Analytical Pyrolysis Coupled with Multidimensional Gas Chromatography Mass Spectrometry

Biomass storage operation is one major source of feedstock quality variability that impacts on downstream preprocessing, feeding, handling and conversion into biofuels, chemicals and products. In field Ccorn stover biomass bales undergoes degradation and cell wall components modification resulting from microbial biological heating occurring during storage. A molecular characterization of the modification was achieved to unveil and understand the changes of structural cell wall modification in corn stover samples by conducting low temperature (400°C) pyrolysis, comparing samples that were mildly biologicallyun heated to those that had been subjected to microbial severe biological heating (~60°C). Pyrolysis of the samples originating from biomass that had been heated during storage generated small oxygenates such as furfural, 5-methylfurfural and 2-(5H)-furanone with efficiencies that were as much as ten times greater than those measured for the mildly unheated samples. Most of the compounds having enhanced efficiencies were C5 oxygenates, suggesting that the pyrolysis products may be formed from hemicellulosic precursor polymers in the corn stover. The findings suggest that microbial heating may be disrupting the cell wall structure, fragmenting the hemicellulose or cellulose chains, generating more polymer termini that have higher efficiency for generating the oxygenates at lower temperatures. Pyrolysis variability with temperature may be a beneficial strategy for improved biomass cell wall characterization, and for guiding control strategies for enhanced control over product distributions , providing insights to understand and manage the feedstock variability as well as to inform harvest and storage best management practices.

09 BIOMASS FUELS↗
NASA NTRS1997

Electrolysis Performance Improvement Concept Study (EPICS) Flight Experiment-Reflight

The Electrolysis Performance Improvement Concept Study (EPICS) is a flight experiment to demonstrate and validate in a microgravity environment the Static Feed Electrolyzer (SFE) concept which was selected for the use aboard the International Space Station (ISS) for oxygen (O2) generation. It also is to investigate the impact of microgravity on electrochemical cell performance. Electrochemical cells are important to the space program because they provide an efficient means of generating O2 and hydrogen (H2) in space. Oxygen and H2 are essential not only for the survival of humans in space but also for the efficient and economical operation of various space systems. Electrochemical cells can reduce the mass, volume and logistical penalties associated with resupply and storage by generating and/or consuming these gases in space. An initial flight of the EPICS was conducted aboard STS-69 from September 7 to 8, 1995. A temperature sensor characteristics shift and a missing line of software code resulted in only partial success of this initial flight. Based on the review and recommendations of a National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) review team a reflight activity was initiated to obtain the remaining desired results, not achieved during the initial flight.

Schubert, F. H.↗
DOE OSTI2020

Synergistic catalysis by Mn promoted ceria for molecular oxygen assisted epoxidation

Mesoporous manganese doped cerium oxide catalysts were prepared by an inverse micelle method with different manganese loadings. These materials exhibited superior activity for epoxidation of alkenes with molecular oxygen. Highest active 10MnCe material showed an activity of 80 % conversion and >99 % selectivity for cyclooctene epoxidation. The fluorite crystal structure which facilitates the high oxygen mobility, low temperature reducibility, homogeneous distribution of manganese on ceria, nanoparticle nature, higher number of oxygen vacancies, low valent states of manganese and cerium, and the ability to generate reactive oxygen species of the manganese doped cerium oxide could be correlated to the high catalytic activity. The reaction followed first order kinetics with a rate constant of 0.31 h –1 at 100 °C, and the activation energy turned out to be 10.5 kJ/mol. In conclusion, the mechanistic study revealed that the reaction proceeds via a unique mechanism which involves in situ generated superoxide and singlet oxygen species..

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

The Reactivity of Polyethylene Microplastics in Water under Low Oxygen Conditions Using Radiation Chemistry

Polyethylene (PE) is an intensely utilized polymer, which has consequently led to it becoming a common environmental contaminant. PE and other plastic waste are known to be highly persistent in surface waters; however, chemical and physical changes do take place over time, dependent mostly on highly variable natural conditions, such as oxygen (O2) availability. Gamma radiation was used to generate reactive oxygen species, namely hydroxyl radicals, in initially aerated aqueous solutions to simulate the natural weathering of microplastics in waters where there are fluctuations and often depletions in dissolved O2. The headspace of the irradiated PE-containing solutions was probed for the formation of degradation products using solid-phase microextraction (SPME) fibers in combination with gas chromatography mass spectrometry (GCMS). The major species detected were n-dodecane, with trace levels of tridecane, 2-dodecanone, and hexadecane, which were believed to be predominately adsorbed in the PE microplastics in excess of their aqueous solubility limits. Surface characterization by Raman spectroscopy and light and dark field microscopy indicated no change in the chemical composition of the irradiated PE microplastics under low O2 to anaerobic conditions. However, morphological changes were observed, indicating radical combination reactions.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
NASA NTRS2016

Generation of High Pressure Oxygen via Electrochemical Pumping in a Multi-stage Electrolysis Stack

An oxygen pump can produce high-purity high-pressure oxygen. Oxygen ions (O.sup.2-) are electrochemically pumped through a multi-stage electrolysis stack of cells. Each cell includes an oxygen-ion conducting solid-state electrolyte between cathode and anode sides. Oxygen dissociates into the ions at the cathode side. The ions migrate across the electrolyte and recombine at the anode side. An insulator is between adjacent cells to electrically isolate each individual cell. Each cell receives a similar volt potential. Recombined oxygen from a previous stage can diffuse through the insulator to reach the cathode side of the next stage. Each successive stage similarly incrementally pressurizes the oxygen to produce a final elevated pressure.

Setlock, John A↗
NASA NTRS2016

Game Changing Development Program - Next Generation Life Support Project: Oxygen Recovery From Carbon Dioxide Using Ion Exchange Membrane Electrolysis Technology

This report summarizes the Phase I research and development work performed during the March 13, 2015 to July 13, 2016 period. The proposal for this work was submitted in response to NASA Research Announcement NNH14ZOA001N, "Space Technology Research, Development, Demonstration, and Infusion 2014 (SpaceTech-REDDI-2014)," Appendix 14GCD-C2 "Game Changing Development Program, Advanced Oxygen Recovery for Spacecraft Life Support Systems Appendix" The Task Agreement for this Phase I work is Document Control Number: GCDP-02-TA-15015. The objective of the Phase I project was to demonstrate in laboratories two Engineering Development Units (EDU) that perform critical functions of the low temperature carbon dioxide electrolysis and the catalytic conversion of carbon monoxide into carbon and carbon dioxide. The low temperature carbon dioxide electrolysis EDU was built by the University of Delaware with Dr. Feng Jiao as the principal investigator in charge of this EDU development (under NASA Contract NNC15CA04C). The carbon monoxide catalytic conversion EDU was built by the NASA Glenn Research Center with Kenneth Burke as the principal investigator and overall project leader for the development of both EDUs. Both EDUs were successfully developed and demonstrated the critical functions for each process. The carbon dioxide electrolysis EDU was delivered to the NASA Johnson Space Center and the carbon monoxide catalytic conversion EDU was delivered to the NASA Marshall Spaceflight Center.

Oxygen Recovery↗
NASA NTRS2017

Generation of High Pressure Oxygen via Electrochemical Pumping in a Multi-Stage Electrolysis Stack

An oxygen pump can produce high-purity high-pressure oxygen. Oxygen ions (O(2-)) are electrochemically pumped through a multi-stage electrolysis stack of cells. Each cell includes an oxygen-ion conducting solid-state electrolyte between cathode and anode sides. Oxygen dissociates into the ions at the cathode side. The ions migrate across the electrolyte and recombine at the anode side. An insulator is between adjacent cells to electrically isolate each individual cell. Each cell receives a similar volt potential. Recombined oxygen from a previous stage can diffuse through the insulator to reach the cathode side of the next stage. Each successive stage similarly incrementally pressurizes the oxygen to produce a final elevated pressure.

Setlock, John A↗
NASA NTRSDate not supplied

Advanced Alkaline Reversible Cell (AARC) for Production of Hydrogen and Oxygen from ISRU-Generated Water – ACO

NASA needs energy storage for lunar applications where night lasts up to 354 hours. Reversible fuel cell systems are potentially well-suited for long-duration storage but must have high reliability to last the 4-year maintenance cycle. Moving parts (compressors and blowers) are the primary limitation for high reliability fuel cell systems. Further, H2 and O2 have numerous ISRU applications, including propellant, life support, and chemical processes.

Paul Matter↗
DOE OSTI2023

Counterintuitive Catalytic Reactivity of the Aluminum Oxide “Passivation” Shell of Aluminum Nanoparticles Facilitating the Thermal Decomposition of exo -Tetrahydrodicyclopentadiene (JP-10)

High energy density aluminum nanoparticles (AlNP) have been at the center of attention as additives to hydrocarbon jet fuels like exo-tetrahydrodicyclopentadiene (JP-10, C 10 H 16 ) aiming at a superior performance of volume-limited air-breathing propulsion systems. However, a fundamental understanding of the ignition and combustion chemistry of JP-10 in presence of AlNPs has been elusive. Exploiting an isomer-selective comprehensive identification of the decomposition products in a newly designed high temperature chemical microreactor coupled to vacuum ultraviolet photoionization, we reveal an active low temperature heterogeneous surface chemistry commencing at 650 K involving the alumina (Al 2 O 3 ) shell. Contrary to textbook knowledge of an “inactive alumina surface”, this unconventional reactivity, where oxygen is transferred from alumina to JP-10, leads to generating cyclic, oxygenated organics like phenol (C 6 H 5 OH) and 2,4-cyclopentadiene-1-one (C 5 H 4 O) - key tracers of an alumina-mediated interfacial chemistry. Furthermore, this counterintuitive reactivity transforms our knowledge on the (catalytic) processes of alumina-coated AlNPs on the molecular level.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2015

Bosch Reactor Development for High Percentage Oxygen Recovery from Carbon Dioxide

This next Generation Life Support Project entails the development and demonstration of Bosch reaction technologies to improve oxygen recovery from metabolically generated oxygen and/or space environments. A primary focus was placed on alternate carbon formation reactor concepts to improve useful catalyst life for space vehicle applications, and make use of in situ catalyst resources for non-terrestrial surface missions. Current state-of-the-art oxygen recovery systems onboard the International Space Station are able to effectively recover approximately 45 percent of the oxygen consumed by humans and exhausted in the form of carbon dioxide (CO2). Excess CO2 is vented overboard and the oxygen contained in the molecules is lost. For long-duration missions beyond the reaches of Earth for resupply, it will be necessary to recover greater amounts of constituents such as oxygen that are necessary for sustaining life. Bosch technologies theoretically recover 100 percent of the oxygen from CO2, producing pure carbon as the sole waste product. Challenges with this technology revolve around the carbon product fouling catalyst materials, drastically limiting catalyst life. This project successfully demonstrated techniques to extend catalyst surface area exposure times to improve catalyst life for vehicle applications, and demonstrated the use of Martian and lunar regolith as viable catalyst Bosch Reactor Development for High Percentage Oxygen Recovery From Carbon Dioxide materials for surface missions. The Bosch process generates carbon nanotube formation within the regolith, which has been shown to improve mechanical properties of building materials. Production of bricks from post reaction regolith for building and radiation shielding applications were also explored.

Howard, David↗
DOE OSTI2020

Detailed Characterization of an Annealed Reduced Graphene Oxide Catalyst for Selective Peroxide Formation Activity

Recently, electrochemical hydrogen peroxide (H 2 O 2 ) generation from oxygen molecules has been extensively studied. Thus far, the best peroxide activity under alkaline conditions has been reported at the surface of a mild reduced graphene oxide annealed at 600 °C (mrGO-600). However, the detailed material information, such as chemical functionality and structural morphology, is unknown, which results in ambiguous debates on its catalytic active sites. Therefore, to solve this problem, we intensively characterize the structure of mrGO-600 to clarify the origin of its catalytic activity. Various characterizations, including X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, near-edge X-ray absorption fine spectroscopy, and high-resolution transmittance electron microscopy coupled with in situ infrared spectroelecrochemistry, reveal that the annealing process generates not only various hole edge defects that are related to the ring ether group but also numerous point defects that result in a small-sized disconnected graphitic carbon region. These defects are believed to form a unique atomic level configuration in mrGO-600, which enables it to facilitate high peroxide-generated activity from oxygen molecules in an alkaline electrolyte.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Circumventing Radical Generation on Fe–V Atomic Pair Catalyst for Robust Oxygen Reduction and Zinc–Air Batteries

Iron–nitrogen–carbon (Fe–N–C) catalysts are considered the most active platinum-free alternative for oxygen reduction reaction (ORR), yet the generated reactive oxygen species (ROS) from general mechanistic pathway rapidly impair the ORR activity and stability of Fe–N–C. Herein, we establish and report an ORR pathway-switching strategy to circumvent ROS generation and fundamentally improve the activity and stability of Fe–N–C via DFT guided catalyst design. The constructed Fe–V atomic pair catalyst (Fe 1 V 1 -NC) with N 2 Fe-N 2 -VN 2 configuration enables side-on adsorption of O 2 and subsequent direct-breaking of the O═O bond to form O*, thereby avoiding the formation of ROS radicals. Importantly, there is intersite electron interaction between FeN 4 and VN 4 , which further boosts the ORR activity. Consequently, Fe 1 V 1 -NC exhibits outstanding ORR activity with onset and half-wave (E 1/2 ) potentials at 1.02 and 0.89 V versus RHE, respectively, in 0.1 M KOH. Record-high stability is achieved on Fe 1 V 1 -NC with a minimal decay in E 1/2 by 16 mV over 50000 cycles, surpassing Fe–N–C counterpart and most of the catalysts reported to date. The Fe 1 V 1 -NC-based zinc-air battery reported here demonstrates exceptional durability up to 400 h at 10 mA·cm −2 . This work identifies the intrinsic correlation between ORR pathway, activity, and stability, advancing development of stable catalytic systems.

Fe-N-C↗
NASA NTRS1971

The development of a noncryogenic nitrogen/oxygen supply technique

A development program was conducted in two phases to define the characteristics and requirements of an electrochemical oxygen/nitrogen supply technique for space station application. In Phase 1, electrode formulations and structures suitable for use as anodes in an oxygen/nitrogen generator were experimentally investigated. A one-man model oxygen/nitrogen generator integrated with a space cabin atmosphere simulator was fabricated and successfully tested in Phase 2. Data from these tests were used to update a computer routine model of the cabin atmosphere control using the oxygen/nitrogen generator technique. A specification and preliminary design for a 12-man oxygen/ nitrogen generation system was prepared.

Greenough, B. M.↗
NASA NTRS1961

Performance of a Small Gas Generator Using Liquid Hydrogen and Liquid Oxygen

The performance and operating problems of a small hot-gas generator burning liquid hydrogen with liquid oxygen are presented. Two methods of ignition are discussed. Injector and combustion chamber design details based on rocket design criteria are also given. A carefully fabricated showerhead injector of simple design provided a gas generator that yielded combustion efficiencies of 93 and 96 percent.

Acker, Loren W.↗
DOE OSTI2020

Time- and strain-dependent nanoscale structural degradation in phase change epitaxial strontium ferrite films

Topotactic phase transition between metallic, perovskite SrFeO 3 and insulating, Brownmillerite SrFeO 2.5 has been extensively studied due to the potential applications in resistive switching devices for neuromorphic computing. However, its practical utilization as memristors has been hindered by the structural instability of SrFeO 3 , which is often ascribed to the generation of oxygen vacancies to form SrFeO 3-δ . Here we reveal the dominating defects generated in SrFeO 3 epitaxial thin films are atomic scale gaps as a result of interfacial strain. Our correlated time- and strain-dependent measurements show that tensile strained SrFeO 3 films form vertical, nanoscale gaps that are SrO-rich, which are accountable for the observed metal-to-insulator transition over time. While compressively strained or small lattice mismatched SrFeO 3 films mainly yield horizontal gaps with a smaller impact on the in-plane transport. The atomic scale origin of such defects and their impact on device performance need to be further understood in order to integrate phase change materials in oxide electronics.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Real-Time Identification of Oxygen Vacancy Centers in LiNbO 3 and SrTiO 3 during Irradiation with High Energy Particles

Oxygen vacancies are known to play a central role in the optoelectronic properties of oxide perovskites. A detailed description of the exact mechanisms by which oxygen vacancies govern such properties, however, is still quite incomplete. The unambiguous identification of oxygen vacancies has been a subject of intense discussion. Interest in oxygen vacancies is not purely academic. Precise control of oxygen vacancies has potential technological benefits in optoelectronic devices. In this review paper, we focus our attention on the generation of oxygen vacancies by irradiation with high energy particles. Irradiation constitutes an efficient and reliable strategy to introduce, monitor, and characterize oxygen vacancies. Unfortunately, this technique has been underexploited despite its demonstrated advantages. This review revisits the main experimental results that have been obtained for oxygen vacancy centers (a) under high energy electron irradiation (100 keV–1 MeV) in LiNbO 3 , and (b) during irradiation with high-energy heavy (1–20 MeV) ions in SrTiO 3 . In both cases, the experiments have used real-time and in situ optical detection. Moreover, the present paper discusses the obtained results in relation to present knowledge from both the experimental and theoretical perspectives. Our view is that a consistent picture is now emerging on the structure and relevant optical features (absorption and emission spectra) of these centers. One key aspect of the topic pertains to the generation of self-trapped electrons as small polarons by irradiation of the crystal lattice and their stabilization by oxygen vacancies. What has been learned by observing the interplay between polarons and vacancies has inspired new models for color centers in dielectric crystals, models which represent an advancement from the early models of color centers in alkali halides and simple oxides. The topic discussed in this review is particularly useful to better understand the complex effects of different types of radiation on the defect structure of those materials, therefore providing relevant clues for nuclear engineering applications.

36 MATERIALS SCIENCE↗