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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 199 records · Page 11

Effect of Thermomechanical Processing on the Microstructure, Properties, and Work Behavior of a Ti50.5 Ni29.5 Pt20 High-Temperature Shape Memory Alloy

TiNiPt shape memory alloys are particularly promising for use as solid state actuators in environments up to 300 C, due to a reasonable balance of properties, including acceptable work output. However, one of the challenges to commercializing a viable high-temperature shape memory alloy (HTSMA) is to establish the appropriate primary and secondary processing techniques for fabrication of the material in a required product form such as rod and wire. Consequently, a Ti(50.5)Ni(29.5)Pt20 alloy was processed using several techniques including single-pass high-temperature extrusion, multiple-pass high-temperature extrusion, and cold drawing to produce bar stock, thin rod, and fine wire, respectively. The effects of heat treatment on the hardness, grain size, room temperature tensile properties, and transformation temperatures of hot- and cold-worked material were examined. Basic tensile properties as a function of temperature and the strain-temperature response of the alloy under constant load, for the determination of work output, were also investigated for various forms of the Ti(50.5)Ni(29.5)Pt20 alloy, including fine wire.

Noebe, Ronald↗

Microgravity Effects on Nonequilibrium Melt Processing of Neodymium Titanate: Thermophysical Properties, Atomic Structure, Glass Formation and Crystallization

The relationships between materials processing and structure can vary between terrestrial and reduced gravity environments. As one case study, we compare the nonequilibrium melt processing of a rare-earth titanate, nominally 83TiO 2 -17Nd 2 O 3 , and the structure of its glassy and crystalline products. Density and thermal expansion for the liquid, supercooled liquid, and glass are measured over 300–1850 °C using the Electrostatic Levitation Furnace (ELF) in microgravity, and two replicate density measurements were reproducible to within 0.4%. Cooling rates in ELF are 40–110 °C s −1 lower than those in a terrestrial aerodynamic levitator due to the absence of forced convection. X-ray/neutron total scattering and Raman spectroscopy indicate that glasses processed on Earth and in microgravity exhibit similar atomic structures, with only subtle differences that are consistent with compositional variations of ~2 mol. % Nd 2 O 3 . The glass atomic network contains a mixture of corner- and edge-sharing Ti-O polyhedra, and the fraction of edge-sharing arrangements decreases with increasing Nd 2 O 3 content. X-ray tomography and electron microscopy of crystalline products reveal substantial differences in microstructure, grain size, and crystalline phases, which arise from differences in the melt processes.

thermophysical properties↗

Effect of processing variables on the thermophysical properties of polybenzimidazole foams

The relationships are described among prepolymer purity, processing parameters, and additives to the thermophysical and chemical properties of polybenzimidazole foams in the density range from 24 to 80 kg/cu m. Foam properties are shown to be affected by differences in prepolymer purity, curing schedule, and the presence of additives in the foam. High-temperature compressive properties were improved by postcuring at 527 C. Surfactant additives were found to improve uniformity of cell size. Foams were characterized according to high-temperature mechanical properties, density, porosity, thermal diffusivity, thermal conductivity, and specific heat.

Kourtides, D. A.↗

Process feasibility study in support of silicon material, task 1

Analyses of process system properties were continued for materials involved in the alternate processes under consideration for semiconductor silicon. Primary efforts centered on physical and thermodynamic property data for dichlorosilane. The following property data are reported for dichlorosilane which is involved in processing operations for solar cell grade silicon: critical temperature, critical pressure, critical volume, critical density, acentric factor, vapor pressure, heat of vaporization, gas heat capacity, liquid heat capacity and density. Work was initiated on the assembly of a system to prepare binary gas mixtures of known proportions and to measure the thermal conductivity of these mixtures between 30 and 350 C. The binary gas mixtures include silicon source material such as silanes and halogenated silanes which are used in the production of semiconductor silicon.

Li, K. Y.↗

Simulating the Surface of Venus on Earth

The growing interest in comparative climatology among the terrestrial planets, the explosion of planets being discovered around other stars and the exciting results of recent orbital and remote observations of Venus provide evidence for a growing case to better understand Earths sister planet. The surface of Venus is quite unlike Earths surface conditions, and in fact is rather extreme. Science, technology, and planetary mission communities have a growing interest in the unique physiochemical properties and processes that occur under extreme temperature and pressure conditions in exotic and even hostile chemical environments such as Venus. The steadily growing catalog of exoplanets likely contains many examples of bodies with environments dramatically different than the surface of the Earth. Understanding these properties and processes will help us under-stand the history and present day state of inhospitable and even inaccessible regions of the Earth as well as other solar or extrasolar planets. Additionally, Venus and Saturn targets are prioritized in the current Planetary Decadal Survey, with reference missions that include in-situ investigations of these challenging environments. The fact that two of the five recent Discovery mission proposals selected by NASA for further development are Venus-focused adds additional priority and even urgency to laboratory-based extreme environment investigations. In addition to the importance of science-focused investigations, there is a current and future need for understanding the behavior of advanced technologies and materials in these extreme environments. The materials of course make up instruments and systems in missions and ultimately the success of planetary missions is dependent upon performance testing of instruments and systems in conditions that closely approximate those of the target. Until very recently, there was limited ability to accurately simulate Venus surface-like conditions, especially in vessels large enough to accommodate full-size instruments and components. This gap in capability is being addressed by NASA Glenn's Extreme Environment Rig, called GEER, located in Cleveland, Ohio. This large chamber allows for engineering tests of newly-developed as well as heritage instruments, while simultaneously affording opportunities for geochemical and materials-based science investigations.

Simulation↗

Uranus

The present publication discusses Uranus and its interior, atmosphere, rings, satellites, and magnetosphere. Attention is given to photochemistry and vertical mixing, spectroscopy and chemistry of the Uranian atmosphere, the thermal structure and energy balance of Uranian atmospheric dynamics and circulations, and clouds and aerosols in the Uranian atmosphere. Topics considered include particle properties and processes in Uranus' rings, the origin and properties of the Uranian satellites, the geology and cratering of the Uranian satellites, and the planet's magnetic field and magnetospheric configuration. Also addressed are wave-particle interactions in the Uranian magnetosphere, the magnetic field and magnetospheric configuration of Uranus, the plasma environment of Uranus, and Uranus as a radio source.

Bergstralh, Jay T.↗

Soft computing in design and manufacturing of advanced materials

The potential of fuzzy sets and neural networks, often referred to as soft computing, for aiding in all aspects of manufacturing of advanced materials like ceramics is addressed. In design and manufacturing of advanced materials, it is desirable to find which of the many processing variables contribute most to the desired properties of the material. There is also interest in real time quality control of parameters that govern material properties during processing stages. The concepts of fuzzy sets and neural networks are briefly introduced and it is shown how they can be used in the design and manufacturing processes. These two computational methods are alternatives to other methods such as the Taguchi method. The two methods are demonstrated by using data collected at NASA Lewis Research Center. Future research directions are also discussed.

Cios, Krzysztof J.↗

Microstructural and Mechanical Property Characterization of Shear Formed Aerospace Aluminum Alloys

Advanced manufacturing processes such as near-net-shape forming can reduce production costs and increase the reliability of launch vehicle and airframe structural components through the reduction of material scrap and part count and the minimization of joints. The current research is an investigation of the processing-microstructure-property relationships for shear formed cylinders of the Al-Cu-Li-Mg-Ag alloy 2195 for space applications and the Al-Cu-Mg-Ag alloy C415 for airframe applications. Cylinders which had undergone various amounts of shear-forming strain were studied to correlate the grain structure, texture, and mechanical properties developed during and after shear forming.

Troeger, Lillianne P.↗

Bringing Research to New Heights: How CASEI Integrates Data Curation, Discovery, and Education in Earth and Atmospheric Science

A challenging aspect of any project is finding all the relevant data and information needed to address the research objective. Searching for data and its contextual metadata can become overwhelming for both undergraduate and graduate students, potentially hindering their work and affecting the scientific discoveries that could be made in the long run. To ease this, the NASA Airborne Data Management Group (ADMG), part of the Interagency Implementation and Advanced Concepts Team (IMPACT), has developed the new Catalog of Archived Suborbital Earth science Investigations (CASEI). CASEI includes a web portal that users, be they professionals or students, can use to search, browse, discover, and locate relevant observations associated with NASA’s airborne and field campaigns. Users are able to query data in a variety of ways (via keywords, locations, timeframe, etc) from one online portal, minimizing the amount of time needed to search. CASEI also allows access to key contextual metadata and data from a wide array of Earth and Atmospheric Science topics such as aerosols and boundary layer processes, as well as ice and glacial properties or processes. Users are able to access the data via DOI links to data set landing pages. This presentation will demonstrate how CASEI can be used for classwork and student research. Teachers can provide CASEI to their students as a tool for their studies, or use it to find data themselves while constructing their curriculums. Additionally, users can leverage CASEI to learn about NASA’s Earth and Atmospheric Science research efforts and to find data relevant for assignments or other research projects. The metadata in CASEI has been carefully curated, and highlights important information about the campaigns and their data. Students can explore and learn about the scientific objectives of the campaigns, as well as descriptions of the campaign’s best research days. Having access to contextual metadata in an easy to understand way can help plant the seeds of new ideas in students at any point in their academic journey. From class projects to theses/dissertations and other research, CASEI is a valuable emerging tool for data discovery, giving access to all users and guiding researchers to NASA’s unique airborne data to answer the burning Earth Science questions of our time.

education↗

Process feasibility study in support of silicon material task 1

Process system properties are analyzed for materials involved in the alternate processes under consideration for solar cell grade silicon. The following property data are reported for trichlorosilane: critical constants, vapor pressure, heat of vaporization, gas heat capacity, liquid heat capacity, density, surface tension, viscosity, thermal conductivity, heat of formation, and Gibb's free energy of formation. Work continued on the measurement of gas viscosity values of silicon source materials. Gas phase viscosity values for silicon tetrafluoride between 40 C and 200 C were experimentally determined. Major efforts were expended on completion of the preliminary economic analysis of the silane process. Cost, sensitivity and profitability analysis results are presented based on a preliminary process design of a plant to produce 1,000 metric tons/year of silicon by the revised process.

Li, K. Y.↗

Applying state diagrams to food processing and development

The physical state of food components affects their properties during processing, storage, and consumption. Removal of water by evaporation or by freezing often results in formation of an amorphous state (Parks et al., 1928; Troy and Sharp, 1930; Kauzmann, 1948; Bushill et al., 1965; White and Cakebread, 1966; Slade and Levine, 1991). Amorphous foods are also produced from carbohydrate melts by rapid cooling after extrusion or in the manufacturing of hard sugar candies and coatings (Herrington and Branfield, 1984). Formation of the amorphous state and its relation to equilibrium conditions are shown in Fig. 1 [see text]. The most important change, characteristic of the amorphous state, is noticed at the glass transition temperature (Tg), which involves transition from a solid "glassy" to a liquid-like "rubbery" state. The main consequence of glass transition is an increase of molecular mobility and free volume above Tg, which may result in physical and physico-chemical deteriorative changes (White and Cakebread, 1966; Slade and Levine, 1991). We have conducted studies on phase transitions of amorphous food materials and related Tg to composition, viscosity, stickiness, collapse, recrystallization, and ice formation. We have also proposed that some diffusion-limited deteriorative reactions are controlled by the physical state in the vicinity of Tg (Roos and Karel, 1990, 1991a, b, c). The results are summarized in this article, with state diagrams based on experimental and calculated data to characterize the relevant water content, temperature, and time-dependent phenomena of amorphous food components.

Non-NASA Center↗

Preparation and metallurgical properties of low gravity processed immiscible materials

Initial experiments conducted during the Apollo 14 mission demonstrated that unique dispersions of immiscible materials could be obtained by processing in a low gravity environment. Subsequently, seven metallic systems have been processed in three NASA facilities: the drop tower at MSFC, the M-512 facility on board a KC-135 aircraft and the M-518 furnace on board Skylab. All couples were solidified from the liquid while in a low gravity environment, with one gravity processed specimens as controls. Metallographic examination demonstrated that the specimens processed in a low gravity environment exhibited a more uniform dispersion and microstructure than the one gravity processed controls.

Reger, J. L.↗

Phenylethynyl Containing Imide Oligomers

As part of a program to develop high performance/high temperature adhesives and composite matrices for a Mach 2.4 high speed civil transport, imide oligomers containing phenylethynyl groups were investigated. Phenylethynyl groups were placed on the ends of oligomers of different molecular weights (1250, 2500 and 5000 g/mol), pendent along the backbone of oligomers and both pendent and terminal on oligomers. Many different compositions of phenylethynyl containing imide oligomers had been previously prepared and evaluated before selecting the composition based upon 3,3'.4,4'-biphenyltetracarboxcylic dianhydride (BPDA), 3.4'-oxydianiline (3,4'-ODA) and 1,3-bis(3-aminophenoxy)benzene (APB) for extensive work. 4-Phenylethynylphthalic anhydride (PEPA) was used to place phenylethynyl groups on the ends of the oligomers and 3,5-diamino-4'-phenylethynylbenzophenone (DPEB) was used to introduce pendent phenylethynyl groups along the oligomeric backbone. Upon heating above 300 C, the phenylethynyl groups react to provide chain extension, branching and cross linking. Several of these materials exhibited excellent properties as adhesives and composite matrices. The chemistry, processability and properties of the oligomers, the cured polymers, bonded specimens and composites from phenylethynyl containing oligomers are presented.

Hergenrother, P. M.↗

Regulatory gene networks and the properties of the developmental process

Genomic instructions for development are encoded in arrays of regulatory DNA. These specify large networks of interactions among genes producing transcription factors and signaling components. The architecture of such networks both explains and predicts developmental phenomenology. Although network analysis is yet in its early stages, some fundamental commonalities are already emerging. Two such are the use of multigenic feedback loops to ensure the progressivity of developmental regulatory states and the prevalence of repressive regulatory interactions in spatial control processes. Gene regulatory networks make it possible to explain the process of development in causal terms and eventually will enable the redesign of developmental regulatory circuitry to achieve different outcomes.

Non-NASA Center↗

Process Feasibility Study in Support of Silicon Material Task 1

Analysis of process system properties was continued for silicon source materials under consideration for producing silicon. The following property data are reported for dichlorosilane which is involved in processing operations for silicon: critical constants, vapor pressure, heat of vaporization, heat capacity, density, surface tension, thermal conductivity, heat of formation and Gibb's free energy of formation. The properties are reported as a function of temperature to permit rapid engineering usage. The preliminary economic analysis of the process is described. Cost analysis results for the process (case A-two deposition reactors and six electrolysis cells) are presented based on a preliminary process design of a plant to produce 1,000 metric tons/year of silicon. Fixed capital investment estimate for the plant is $12.47 million (1975 dollars) ($17.47 million, 1980 dollars). Product cost without profit is 8.63 $/kg of silicon (1975 dollars)(12.1 $/kg, 1980 dollars).

Li, K. Y.↗

3D Woven Mid-Density Carbon Phenolic (3MDCP) Full-Scale Heatshield Development for Mars Sample Return (MSR) Earth Entry System (EES)

The Mars Sample Return (MSR) mission will be returning samples of Martian soil to Earth. The samples will be returned in the Earth Entry System (EES). The EES capsule is protected by a new thermal protection system; the 3-Dimensionally Woven, Mid-Density, Carbon Phenolic (3MDCP) material which is derived from the Heatshield for Extreme Entry Environment Technology (HEEET). The baseline 3MDCP design is a single piece thermal protection system that avoids the manufacturing and certification challenges associated with a tiled configuration. A 3MDCP heatshield begins as a flat woven preform that is formed to the final heatshield shape and then infused with phenolic resin. A NASA Ames lead team, in collaboration with Spirit Textiles (formerly TEAM Inc.), Fiber Materials Inc. (FMI, a Spirit AeroSystems Company), and Kratos SRE, has been developing and demonstrating the processes to fabricate the 3MDCP heatshield and characterize the resulting properties. The process of forming the flat woven preform into the final heatshield shape, a sphere-cone geometry with a 52.5° cone angle, involves local but substantial movement of the yarns in the weave. This results in continuous fibers across the single piece heatshield, albeit with property variations between different regions of the heatshield. This presentation will provide a high-level status of 3MDCP development for the MSR EES heatshield. This will include an overview of the manufacturing processes with an emphasis on the impact of forming on fiber orientation, material properties, and performance. Results comparing preliminary formed and flat materials will be shown. Additionally, the presentation will layout the broader plan for property testing and tie-in to aerothermal performance.

Peter Edward Marshall↗

Potential for Remotely Sensed Soil Moisture Data in Hydrologic Modeling

Many hydrologic processes display a unique signature that is detectable with microwave remote sensing. These signatures are in the form of the spatial and temporal distributions of surface soil moisture and portray the spatial heterogeneity of hydrologic processes and properties that one encounters in drainage basins. The hydrologic processes that may be detected include ground water recharge and discharge zones, storm runoff contributing areas, regions of potential and less than potential ET, and information about the hydrologic properties of soils and heterogeneity of hydrologic parameters. Microwave remote sensing has the potential to detect these signatures within a basin in the form of volumetric soil moisture measurements in the top few cm. These signatures should provide information on how and where to apply soil physical parameters in distributed and lumped parameter models and how to subdivide drainage basins into hydrologically similar sub-basins.

Engman, Edwin T.↗