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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
NASA NTRS1986

Brown dwarfs and Jovian planets: A comparison

The recent detection of a subluminous companion to the M dwarf star VB8 has renewed interest in the characteristics of objects spanning the mass range from Jupiter to hydrogen burning stars. Atmospheric and interior models were constructed for objects in this mass regime, up to 30 Jupiter masses, with emphasis on understanding the relationship of brown dwarfs such as the VB8 companion to the better-studied Jovian planets. The atmospheric model solves the equation of radiative transfer assuming frequency dependent molecular opacity sources H2, He, H2O, CO, and CH4 which are important by virtue of the high cosmic abundance of their constituent atoms. Condensation of cosmochemically important materials, iron and silicates, in the atmosphere is possible, and the effect of such grains as opacity sources is assessed. The luminosity of the object is presumed due to degenerate cooling following a collapse phase and possibly deuterium burning and an interior model is constructed using as an outer boundary condition the temperature and pressure level at which the atmosphere becomes convective. The interior model is analogous to Jupiter, with a large liquid metallic-hydrogen core and a thinner molecular-hydrogen envelope. The oxidation state of carbon in the outer envelope of a brown dwarf of similar age to Jupiter is a function of the object's mass. This makes the wavelength dependence of the atmospheric opacity sensitive to the carbon to oxygen ratio, since the abundance of the primary source of molecular opacity, H2O, decreases as more oxygen is tied up as CO.

Lunine, J. I.↗
NASA NTRS1946

The synthesis and purification of aromatic hydrocarbons V : 1-ethyl-3-methylbenzene

The method used for the synthesis and purification of an 8-gallon quantity of 1-ethyl-3-methylbenzene from m-creosol consists in obtaining m-methylcyclohexanone from m-creosol by hydrogenation followed by oxidation, condensation of the ketone with ethylmagnesium bromide, dehydration of the tertiary alcohol obtained, and the dehydration of the olefins to 1-ethyl-3-methylbenzene. A yield of 28 percent of the theoretical was obtained from 98 percent commercial m-creosol. The physical properties of the 1-ethyl-3-methylbenzene are compared with selected values from the literature.

Ebersole, Earl R↗
NASA NTRS1997

Development of High Temperature Gas Sensor Technology

The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

Hunter, Gary W.↗
NASA NTRS1998

Microfabricated Chemical Sensors for Safety and Emission Control Applications

Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

Hunter, G. W.↗
NASA NTRS2001

Innovative Method for Developing a Helium Pressurant Tank Suitable for the Upper Stage Flight Experiment

The AFRL USFE project is an experimental test bed for new propulsion technologies. It will utilize ambient temperature fuel and oxidizers (Kerosene and Hydrogen peroxide). The system is pressure fed, not pump fed, and will utilize a helium pressurant tank to drive the system. Mr. DeLay has developed a method for cost effectively producing a unique, large pressurant tank that is not commercially available. The pressure vessel is a layered composite structure with an electroformed metallic permeation barrier. The design/process is scalable and easily adaptable to different configurations with minimal cost in tooling development 1/3 scale tanks have already been fabricated and are scheduled for testing. The full-scale pressure vessel (50" diameter) design will be refined based on the performance of the sub-scale tank. The pressure vessels have been designed to operate at 6,000 psi. a PV/W of 1.92 million is anticipated.

DeLay, Tom K.↗
NASA NTRS2005

Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors; 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity; 3) The development of high temperature semiconductors, especially silicon carbide. This presentation discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

Hunter, Gary W.↗
NASA NTRS2006

Early Validation Analyses of Atmospheric Profiles from EOS MLS on the Aura Satellite

We present results of early validation studies using retrieved atmospheric profiles from the Earth Observing System Microwave Limb Sounder (MLS) instrument on the Aura satellite. 'Global' results are presented for MLS measurements of atmospheric temperature, ozone, water vapor, hydrogen chloride, nitrous oxide, nitric acid, and carbon monoxide, with a focus on the January-March 2005 time period. These global comparisons are made using long-standing global satellites and meteorological datasets, as well as some measurements from more recently launched satellites. Comparisons of MLS data with measurements from the Ft. Sumner, NM, September 2004 balloon flights are also presented. Overall, good agreeement is obtained, often within 5% to 10%, but we point out certain issues to resolve and some larger systematic differences; some artifacts in the first publicly released MLS (version 1.5) dataset are noted.We comment briefly on future plans for validation and software improvements.

Atmospheric retrievals↗
NASA NTRS2009

Design and Activation of a LOX/GH Chemical Steam Generator

The purpose of this paper is to give a detailed description of the design and activation of the LOX/GH fueled chemical steam generator installed in Cell 2 of the E3 test facility at Stennis Space Center, MS (SSC). The steam generator uses a liquid oxygen oxidizer with gaseous hydrogen fuel. The combustion products are then quenched with water to create steam at pressures from 150 to 450 psig at temperatures from 350 to 750 deg F (from saturation to piping temperature limits).

Saunders, G. P.↗
NASA NTRS2023

Design of a Minimal di-Nickel Hydrogenase Peptide

The most ancient processes for energy production in the evolution of life involve the reversible oxidation of molecular hydrogen by hydrogenase. Extant hydrogenase enzymes are complex, comprising hundreds of amino acids and multiple cofactors. We designed a 13 amino acid nickel-binding peptide capable of robustly producing molecular hydrogen from protons under a wide variety of conditions. The peptide forms a di-nickel cluster structurally analogous to a Ni-Fe cluster in [NiFe]-hydrogenase and the Ni-Ni cluster in acetyl-CoA synthase (ACS), two ancient, extant proteins central to metabolism. These experimental results clearly demonstrate that modern enzymes, despite their enormous complexity, likely evolved from simple peptide precursors on early Earth. One Sentence Summary: Small metal-binding peptides were the likely precursors of modern enzymes.

Joshua A. Mancini↗
NASA NTRS2023

Development of Directed Energy Deposited NASA HR-1 to Optimize Properties for Liquid Rocket Engine Applications

Metal additive manufacturing (AM) processes have been demonstrated to be effective at reducing costs and lead times associated with fabrication of complex propulsion component designs. Laser powder directed energy deposition (LP-DED) is a metal AM technology that has effectively been used to produce a variety of parts for liquid rocket engine applications. The LP-DED technology has enabled new designs and materials for these applications. The National Aeronautics and Space Administration (NASA) has identified the need to develop and advance new materials in unique engine applications such as hydrogen environments. One such metal alloy being developed for these applications is NASA HR-1. A high-strength Fe-Ni based superalloy, NASA HR-1 was designed to resist high pressure hydrogen environment embrittlement, oxidation, and corrosion. Enabled by LP-DED, NASA HR-1 has completed build and heat treatment optimization, characterization, mechanical and thermophysical testing, and hot-fire testing to demonstrate its capability as an alloy used in liquid rocket engine applications. The evolution of the alloy through material characterization analysis and mechanical testing results from development and optimization efforts will be presented.

additive manufacturing↗
NASA NTRS2010

RESOLVE's Field Demonstration on Mauna Kea, Hawaii 2010

In cooperation with the Canadian Space Agency, and the Northern Centre for Advanced Technology, Inc., NASA has undertaken the In-Situ Resource Utilization (ISRU) project called RESOLVE (Regolith and Environment Science & Oxygen and Lunar Volatile Extraction). This project is an Earth-based lunar precursor demonstration of a system that could be sent to explore permanently shadowed polar lunar craters, where it would drill into regolith, quantify the volatiles that are present, and extract oxygen by hydrogen reduction of iron oxides. The resulting water could be electrolyzed into oxygen to support exploration and hydrogen, which would be recycled through the process. The RESOLVE chemical processing system was mounted on a Canadian Space Agency mobility chasis and successfully demonstrated on Hawaii's Mauna Kea volcano in February 2010. The RESOLVE unit is the initial prototype of a robotic prospecting mission to the Moon. RESOLVE is designed to go to the poles of the Moon to "ground truth" the form and concentration of the hydrogen/water/hydroxyl that has been seen from orbit (M3, Lunar Prospector and LRO) and to test technologies to extract oxygen from the lunar regolith. RESOLVE has the ability to capture a one-meter core sample of lunar regolith and heat it to determine the volatiles that may be released and then demonstrate the production of oxygen from minerals found in the regolith. The RESOLVE project, which is led by KSC, is a multi-center and multi-organizational effort that includes representatives from KSC, JSC, GRC, the Canadian Space Agency, and the Northern Center for Advanced Technology (NORCAT). This paper details the results obtained from four days of lunar analog testing that included gas chromatograph analysis for volatile components, remote control of chemistry and drilling operations via satalite communications, and real-time water quantification using a novel capacitance measurement technique.

Captain, Janine↗
NASA NTRS2012

Method to Improve Indium Bump Bonding via Indium Oxide Removal Using a Multi-Step Plasma Process

A process for removing indium oxide from indium bumps in a flip-chip structure to reduce contact resistance, by a multi-step plasma treatment. A first plasma treatment of the indium bumps with an argon, methane and hydrogen plasma reduces indium oxide, and a second plasma treatment with an argon and hydrogen plasma removes residual organics. The multi-step plasma process for removing indium oxide from the indium bumps is more effective in reducing the oxide, and yet does not require the use of halogens, does not change the bump morphology, does not attack the bond pad material or under-bump metallization layers, and creates no new mechanisms for open circuits.

Greer, H. Frank↗
NASA NTRS1979

Recycling plant, human and animal wastes to plant nutrients in a closed ecological system

The essential minerals for plant growth are nitrogen, phosphorous, potassium (macronutrients), calcium, magnesium, sulfur (secondary nutrients), iron, manganese, boron, copper, zinc, chlorine, sodium, and molybdenum (micronutrients). The first step in recycling wastes will undoubtedly be oxidation of carbon and hydrogen to CO2 and H2O. Transformation of minerals to plant nutrients depends upon the mode of oxidation to define the state of the nutrients. For the purpose of illustrating the type of processing required, ash and off-gas compositions of an incineration process were assumed and subsequent processing requirements were identified. Several processing schemes are described for separating out sodium chloride from the ash, leading to reformulation of a nutrient solution which should be acceptable to plants.

Meissner, H. P.↗
NASA NTRS1997

SiC-Based Gas Sensors

Electronic grade Silicon Carbide (SiC) is a ceramic material which can operate as a semiconductor at temperatures above 600 C. Recently, SiC semiconductors have been used in Schottky diode gas sensor structures. These sensors have been shown to be functional at temperatures significantly above the normal operating range of Si-based devices. SiC sensor operation at these higher temperatures allows detection of gases such as hydrocarbons which are not detectable at lower temperatures. This paper discusses the development of SiC-based Schottky diode gas sensors for the detection of hydrogen, hydrocarbons, and nitrogen oxides (NO(x)). Sensor designs for these applications are discussed. High sensitivity is observed for the hydrogen and hydrocarbon sensors using Pd on SiC Schottky diodes while the NO(x) sensors are still under development. A prototype sensor package has been fabricated which allows high temperature operation in a room temperature ambient by minimizing heat loss to that ambient. It is concluded that SiC-based gas sensors have considerable potential in a variety of gas sensing applications.

Chen, Liang-Yu↗
NASA NTRS2017

The Effects of CDKN1a/p21 on Oxidative Stress and Mitochondrial Function During Long Duration Spaceflight

Spaceflight factors, such as microgravity and space radiation, are known to put astronauts at risk for negative effects to their tissue regeneration and degenerative conditions. On our previous spaceflight research, we found that long duration spaceflight produced increased oxidative stress and activation of the inflammatory response as a major contributor to physiological changes, including alterations to the cardiovascular and musculoskeletal systems, metabolism, and the liver. Proliferation, apoptosis, and ion-channel remodeling of vascular smooth muscle cells, as well as endothelial inflammation, and nitric oxide synthase-nitric oxide system regulation have been shown by spaceflight and simulated spaceflight projects. CDKN1ap21 is a regulatory gene for tissue regeneration and also plays an important role in upregulating oxidative stress caused by radiation. In further research, we have also determined CDKN1ap21 to be overexpressed during spaceflight. When knocked out in mice, however, it protects against unloading-induced changes to the morphology and physiology of carotid arteries. In this proposal, we seek to test a potential dietary countermeasure to down-regulate CDKN1ap21 in the mice and protect against oxidative stress in the rodents. Specifically, we will expose both Wildtype and CDKN1ap21-null mice to hydrogen peroxide to induce oxidative stress and observe the molecular mechanisms in which a dietary supplement protects vascular smooth muscle cells against the consequences of the apoptotic environment within Wildtype mice versus the, hypothetically, sound physiology of CDKN1ap21-null mice. The successful completion of this experiment will conclusively determine accuracy of a dietary supplement as a CDKN1ap21 suppressor. This will provide a new perspective on the problem of increased oxidative stress developing into cardiovascular disease as a result of long-term space flight. This research will address the Human Research Plan Roadmaps Risk of Cardiac Rhythm Problems including CV-8, the Risk of Cardiovascular Disease and Other Degenerative Tissue Effects from Radiation Exposure including Degen-6 and Degen-7, and the Risk of Adverse Health Event from Radiation Exposure including IM-8. Additionally, this research will address Space Biology Research Plans questions SBP CMB-1, SBP CMB-3, and SB AN-2.

Oxidative Stress↗
NASA NTRS2006

Hybrid Solid Oxide Fuel Cell/Gas Turbine System Design for High Altitude Long Endurance Aerospace Missions

A system level analysis, inclusive of mass, is carried out for a cryogenic hydrogen fueled hybrid solid oxide fuel cell and bottoming gas turbine (SOFC/GT) power system. The system is designed to provide primary or secondary electrical power for an unmanned aerial vehicle (UAV) over a high altitude, long endurance mission. The net power level and altitude are parametrically varied to examine their effect on total system mass. Some of the more important technology parameters, including turbomachinery efficiencies and the SOFC area specific resistance, are also studied for their effect on total system mass. Finally, two different solid oxide cell designs are compared to show the importance of the individual solid oxide cell design on the overall system. We show that for long mission durations of 10 days or more, the fuel mass savings resulting from the high efficiency of a SOFC/GT system more than offset the larger powerplant mass resulting from the low specific power of the SOFC/GT system. These missions therefore favor high efficiency, low power density systems, characteristics typical of fuel cell systems in general.

Himansu, Ananda↗
NASA NTRS1987

Effect of water on hydrogen permeability

Doping of hydrogen with CO and CO2 was developed to reduce hydrogen permeation in Stirling engines by forming a low permeability oxide coating on the inner surface of the heater head tubes. Although doping worked well, under certain circumstances the protective oxide could be chemically reduced by the hydrogen in the engine. Some oxygen is required in the hydrogen to prevent reduction. Eventually, all the oxygen in the hydrogen gas - whatever its source - shows up as water. This is the result of hydrogen reducing the CO, CO2, or the protective inner surface oxides. This water can condense in the engine system under the right conditions. If the concentration of water vapor is reduced to a low enough level, the hydrogen can chemically reduce the oxide coating, resulting in an increase in permeability. This work was done to define the minimum water content required to avoid this reduction in the oxide coating. The results of this testing show that a minimum of approximately 750 ppm water is required to prevent an increase in permeability of CG-27, a high temperature metal alloy selected for Stirling engine heater tubes.

Hulligan, David↗