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At least 703 records · Page 39

TBC costing

Procedures to be used in determining the cost of producing and installing a parabolic dish collector in annual production volumes of 10,000, 50,000, 100,000, and 1,000,000 units include (1) evaluating each individual part for material cost and for the type and number of operations required to work the raw material into the finished part; (2) costing labor, burden, tooling, gaging, machinery, and equipment; (3) estimating facilities requirements for each production volume; and (4) considering suggestions for design and material alterations that could result in cost reduction.

Kaminski, H. L.↗

Materials properties numerical database system established and operational at CINDAS/Purdue University

A computerized comprehensive numerical database system on the mechanical, thermophysical, electronic, electrical, magnetic, optical, and other properties of various types of technologically important materials such as metals, alloys, composites, dielectrics, polymers, and ceramics has been established and operational at the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) of Purdue University. This is an on-line, interactive, menu-driven, user-friendly database system. Users can easily search, retrieve, and manipulate the data from the database system without learning special query language, special commands, standardized names of materials, properties, variables, etc. It enables both the direct mode of search/retrieval of data for specified materials, properties, independent variables, etc., and the inverted mode of search/retrieval of candidate materials that meet a set of specified requirements (which is the computer-aided materials selection). It enables also tabular and graphical displays and on-line data manipulations such as units conversion, variables transformation, statistical analysis, etc., of the retrieved data. The development, content, accessibility, etc., of the database system are presented and discussed.

Ho, C. Y.↗

Problem of nature of inert gases in lunar surface material

The origin of isotopes of inert gases in lunar surface material was investigated from the standpoint of the isotopic two-component status of inert gases in the solar system. Helium and neon represent the solar wind component, while krypton and xenon are planetary gases. Type A gases are trapped by the material of the regolith in the early stages of the existence of the solar system and were brought to the lunar surface together with dust. The material of the regolith therefore cannot be considered as the product of the erosion of the crystalline rocks of the moon and in this sense are extralunar. The regolith material containing type A gases must be identified with the high temperature minerals of the carbonaceous chondrites.

Levskiy, L. K.↗

Friction and wear of carbon-graphite materials for high-energy brakes

Caliper type brake simulation experiments were conducted on seven different carbon graphite materials formulations against a steel disk material and against a carbon graphite disk material. The effects of binder level, boron carbide (B4C) additions, SiC additions, graphite fiber additions, and graphite cloth reinforcement on friction and wear behavior were investigated. Reductions in binder level, additions of B4C, and additions of SiC each resulted in increased wear. The wear rate was not affected by the addition of graphite fibers. Transition to severe wear and high friction was observed in the case of graphite-cloth-reinforced carbon sliding against a disk of similar composition. The transition was related to the disruption of a continuous graphite shear film that must form on the sliding surfaces if low wear is to occur.

Bill, R. C.↗

The structure and properties of rapidly solidified high alloy aluminum materials

A series of 2024 type aluminum alloys modified by additions of 1 to 2% Li were studied to determine the role of the Cu:Li and the (Cu + Mg):Li ratios on resultant strength, ductility, notch-tensile behavior, and crack propagation rates. Ultrasonically gas atomized powders with quench rates of 10 to 100 thousand degrees/s were atomized in an argon atmosphere, producing yields of powder such that almost 100% was finer than 250 microns. The powders are free of gases and porosity, are quite spherical, have few satellites (adhering fine powder particles) and are of uniform microstructure. Strength properties are such that yield strength is 20% greater than for lithium-free 2024 ingot alloy, tensile strength is 10% greater than that of 2024 ingot material, and ductilities are comparable. In terms of specific strength and specific modulus, these RS 2024-Li alloys are significantly better than IM 2024.

Grant, N. J.↗

Design of Amphoteric Refraction Models Using WAVICA and RAYICA

The phenomenon of refraction of light is due to refractive index mismatches in two different media. However, to achieve this effect, a finite reflection loss is inevitable. A recent finding presented a unique type of interface, ferroelastic materials, that enables refraction without any reflection for either an electron or a light beam. This property is called total refraction. The same type of interface that yields total refraction can also yield amphoteric refraction, where the index of refraction can be either positive or negative depending on the incident angle. This interface could potentially be used to steer light without reflections which could have major applications in high power optics. My goal this summer is to first familiarize myself with the Mathematica software, especially the Wavica and Rayica packages. I will then model the amphoteric refraction by either modifying the Wavica and Rayica packages or using the built-in functions in these packages.

Su, Richard↗

Preparation and Thermoelectric Properties of IR(sub x)Co(sub 1-x)Sb(sub 2) Alloys

The preparation and characterization of the binary arsenopyrite compounds CoSb2 and IrSb2 and IrxCo1-xSb2 alloys is reported. Single crystals of CoSb2 were grown by the vertical gradient freeze technique from solution rich in antimony. Polycrystalline samples of IrSb2 and IrxCo1-xSb2 alloys were prepared by hot-pressing of prereacted elemental powders. Samples were investigated by X-ray diffractometry, microprobe analysis and density measurements. It was found that a range of solid solution exist in the system IrxCo1-xSb2 for 0.1<x<0.8. Samples were also characterized by high temperature electrical resistivity, Seebeck coefficient and thermal conductivity measurements. All materials have p-type conductivity and are semiconductors. A band gap of about 0.98 eV was calculated for IrSb2. Preliminary measurements of the thermoelectric properties of these materials showed that their potential for thermoelectric applications is limited.

Thermoelectric Properties↗

Rhenium-osmium and samarium-neodymium isotopic systematics of the Stillwater complex

The role of magma mixing in the formation of strategic platinum-group element ore deposits is examined using isotopic data from the Stillwater Complex, Montana. Nd and Os isotopic data show that the intrusion formed from at least two distinct magmas: ultramafic (U-type) affinity magmas and anorthositic (A-type) affinity magmas. The U-type magmas formed from a lithospheric mantle source containing recycled crustal materials and the A-type magmas originated either by crustal contamination of basaltic magmas or by partial melting of basalt in the lower crust. The results also suggest that the platinum-group element ore deposits were derived from A-type magmas which were injected into the U-type magma chamber at several stages during the development of the ultramafic series.

Lambert, David D.↗

Ultra-Low Heat-Leak, High-Temperature Superconducting Current Leads for Space Applications

NASA Goddard Space Flight Center has a need for current leads used in an adiabatic demagnetization refrigerator (ADR) for space applications. These leads must comply with stringent requirements such as a heat leak of approximately 100 W or less while conducting up to 10 A of electric current, from more than 90 K down to 10 K. Additionally, a length constraint of < 300 mm length and < 50 mm diameter is to be maintained. The need for these current leads was addressed by developing a superconducting hybrid lead. This hybrid lead comprises two different high-temperature superconducting (HTS) conductors bonded together at a thermally and electrically determined optimum point along the length of the current lead. By taking advantage of material properties of each conductor type, employing advanced fabrication techniques, and taking advantage of novel insulation materials, the company was able to develop and fabricate the lightweight, low heat-leak leads currently to NASA's specs.

Rey, Christopher M.↗

Thermoelectric Skutterudite Compositions and Methods for Producing the Same

Compositions related to skutterudite-based thermoelectric materials are disclosed. Such compositions can result in materials that have enhanced ZT values relative to one or more bulk materials from which the compositions are derived. Thermoelectric materials such as n-type and p-type skutterudites with high thermoelectric figures-of-merit can include materials with filler atoms and/or materials formed by compacting particles (e.g., nanoparticles) into a material with a plurality of grains each having a portion having a skutterudite-based structure. Methods of forming thermoelectric skutterudites, which can include the use of hot press processes to consolidate particles, are also disclosed. The particles to be consolidated can be derived from (e.g., grinded from), skutterudite-based bulk materials, elemental materials, other non-Skutterudite-based materials, or combinations of such materials.

Ren, Zhifeng↗

An Overview of Materials Structures for Extreme Environments Efforts for 2015 SBIR Phases I and II

Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for Agency projects. This report highlights innovative SBIR 2015 Phase I and II projects that specifically address areas in Materials and Structures for Extreme Environments, one of six core competencies at NASA Glenn Research Center. Each article describes an innovation, defines its technical objective, and highlights NASA applications as well as commercial and industrial applications. Ten technologies are featured: metamaterials-inspired aerospace structures, metallic joining to advanced ceramic composites, multifunctional polyolefin matrix composite structures, integrated reacting fluid dynamics and predictive materials degradation models for propulsion system conditions, lightweight inflatable structural airlock (LISA), copolymer materials for fused deposition modeling 3-D printing of nonstandard plastics, Type II strained layer superlattice materials development for space-based focal plane array applications, hydrogenous polymer-regolith composites for radiation-shielding materials, a ceramic matrix composite environmental barrier coating durability model, and advanced composite truss printing for large solar array structures. This report serves as an opportunity for NASA engineers, researchers, program managers, and other personnel to learn about innovations in this technology area as well as possibilities for collaboration with innovative small businesses that could benefit NASA programs and projects.

integrated reacting fluid dynamics and predictive ↗

Evaluation and comparison of alternative designs for water/solid-waste processing systems for spacecraft

Promising candidate designs currently being considered for the management of spacecraft solid waste and waste-water materials were assessed. The candidate processes were: (1) the radioisotope thermal energy evaporation/incinerator process; (2) the dry incineration process; and (3) the wet oxidation process. The types of spacecraft waste materials that were included in the base-line computational input to the candidate systems were feces, urine residues, trash and waste-water concentrates. The performance characteristics and system requirements for each candidate process to handle this input and produce the specified acceptable output (i.e., potable water, a storable dry ash, and vapor phase products that can be handled by a spacecraft atmosphere control system) were estimated and compared. Recommendations are presented.

Spurlock, J. M.↗

The effect of resin toughness and modulus on compressive failure modes of quasi-isotropic graphite/epoxy laminates

Compressive failure mechanisms in quasi-isotropic graphite/epoxy laminates were characterized for both unnotched and notched specimens and also following damage by impact. Two types of fibers (Thornel 300 and 700) and four resin systems (Narmco 5208, American Cyanamid BP907, and Union Carbide 4901/MDA and 4901/mPDA) were studied. For all material combinations, failure of unnotched specimens was initiated by kinking of fibers in the 0-degree plies. A major difference was observed, however, in the mode of failure propagation after the 0-degree ply failure. The strength of quasi-isotropic laminates in general increased with increasing resin tensile modulus. The laminates made with Thornel 700 fibers exhibited slightly lower compressive strengths than did the laminates made with Thornel 300 fibers. The notch sensitivity as measured by the hole strength was lowest for the BP907 resin and highest for the 5208 resin. For the materials studied, however, the type of fiber had no effect on the notch sensitivity.

Sohi, M. M.↗

The effect of resin toughness and modulus on compressive failure modes of quasi-isotropic graphite/epoxy laminates

Compressive failure mechanisms in quasi-isotropic graphite/epoxy laminates were characterized for both unnotched and notched specimens and also following damage by impact. Two types of fibers (Thornel 300 and 700) and four resin systems (Narmco 5208, American Cyanamid BP907, and Union Carbide 4901/MDA and 4901/mPDA) were studied. For all material combinations, failure of unnotched specimens was initiated by kinking of fibers in the 0-degree plies. A major difference was observed, however, in the mode of failure propagation after the 0-degree ply failure. The strength of quasi-isotropic laminates in general increased with increasing resin tensile modulus. The laminates made with Thornel 700 fibers exhibited slightly lower compressive strengths than did the laminates made with Thornel 300 fibers. The notch sensitivity as measured by the hole strength was lowest for the BP907 resin and highest for the 5208 resin. For the materials studied, however, the type of fiber had no effect on the notch sensitivity.

Hahn, H. Thomas↗

Exploration of crustal/mantle material for the earth and moon using reflectance spectroscopy

Near-infrared reflectance spectra have been acquired (1) for Moses Rock diatreme in SE Utah using an airborne imaging spectrometer (AIS) and (2) for small areas in and around the large lunar impact crater Copernicus using a spectrometer on earth-based telescopes. The high spectral resolution and precision of these data allow several mineral components of surface material to be identified and analyzed in a spatial context. The derived mineralogical information is used to address specific geological problems. For the terrestrial study the distribution of the measured abundance of mantle derived ultramafic microbreccia across Moses Rock dike indicates that flow stabilized into a few channels during the violent eruption. For the lunar study the variety of rock types identified in crustal material of deep-seated origin is distinct from the dominant rock types sampled from the upper lunar crust and suggests a complex crustal evolution.

Pieters, Carle M.↗

Friction and wear of carbon-graphite materials for high energy brakes

Caliper-type brakes simulation experiments were conducted on seven different carbon-graphite material formulations against a steel disk material and against a carbon-graphite disk material. The effects of binder level, boron carbide (B4C) additions, graphite fiber additions, and graphite cloth reinforcement on friction and wear behavior were investigated. Reductions in binder level and additions of B4C each resulted in increased wear. The wear rate was not affected by the addition of graphite fibers. Transition to severe wear and high friction was observed in the case of graphite-cloth-reinforced carbon sliding against a disk of similar composition. This transition was related to the disruption of a continuous graphite shear film that must form on the sliding surfaces if low wear is to occur. The exposure of the fiber structure of the cloth constituent is believed to play a role in the shear film disruption.

Bill, R. C.↗

Nano-casted Metal Oxide Aerogels as Dual Purpose Structural Components for Space Exploration

NASA missions and space exploration rely on strong, ultra lightweight materials. Such materials are needed for building up past and present space vehicles such as the Sojourner Rover (1997) or the two MERs (2003), but also for a number of components and/or systems including thermal insulators, Solar Sails, Rigid Aeroshells, and Ballutes. The purpose of my internship here at Glenn Research Center is to make dual purpose materials; materials that in addition to being lightweight have electronic, photophysical and magnetic properties and, therefore, act as electronic components and sensors as well as structural components. One type of ultra lightweight material of great interest is aerogels, which have densities ranging from 0.003 g/cc to 0.8 g/cc . However, aerogels are extremely fragile and, as a result, have limited practical applications. Recently, Glenn Research Center has developed a process of nano-casting polymers onto the inorganic network of silica-based aerogels increasing the strength 300 fold while only increasing the density 3 fold. By combining the process of nano-casting polymers with inorganic oxide networks other than silica, we are actively pursuing lightweight dual purpose materials. To date, thirty different inorganic oxide aerogels have been prepared using either standard sol-gel chemistry or a non-alkoxide method involving metal chloride precursors and an epoxide; epichlorohydrin, propylene oxide or trimethylene oxide, as proton scavengers. More importantly, preliminary investigations show that the residual surface hydroxyl groups on each of these inorganic oxide aerogels can be successfully crosslinked with urethane. In addition to characterizing physical and mechanical properties such as density, strength and flexibility, each of these metal oxide aerogels are being characterized for thermal and electronic conductivity and magnetic and optical properties.

Vassilaras, Plousia E.↗

Electron mobility in n-type Hg(1-x)Cd(x)Te and Hg(1-x)Zn(x)Te alloys

Calculations of electron mobility in n-type mercury cadmium telluride (MCT), a candidate material for IR detectors, and n-type mercury zinc telluride (MZT) are compared. It is found that electron mobilities in MCT and MZT are nearly the same for equivalent energy gaps. The results are also found to compare will with experimental data. Directions of future research are briefly discussed.

Patterson, J. D.↗