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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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11 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

The Mars Environmental Compatibility Assessment MECA Abrasion Tool

The Mars Environmental Compatibility Assessment (MECA) experiment, an instrument suite to be flown on Mars Surveyor 2001, will include a tool for doing simple mineralogical scratch and streak tests on particles from the Martian regolith. The Abrasion Tool will be applied to particles that adhere to highly polished substrates of various hardnesses. Granular soil components will be subjected to a compressive force of about 3 N using a leaf spring. The spring will be applied with a paraffin actuator capable of a 0.76 mm throw to achieve a maximum displacement of about 7.5 mm at the tip of the tool. The pressure per grain will be dependent on the grain size, the number of grains that adhere to the substrate and the number of grains in compression. The pressure per particle is expected to be on the order of 100 MPa - 1 GPa. The MECA sample wheel containing the substrates will be rotated after the particles are placed in compression to produce scratches or pits. A primary goal of the Abrasion Tool is to identify quartz (Mohs' hardness = 7) using substrates of varying hardnesses. Quartz is considered hazardous to future human explorers of Mars because it can cause silicosis of the lungs if it is of respirable size. It is also hazardous to machinery, structures, and space suits because of its ability to abrade and scratch surfaces. Since large quantities of minerals harder than quartz are not expected, any scratches produced on polished quartz substrates might be reasonably attributed to quartz particles, although there may be minerals such as impact metamorphic diamond in the soils. Careful calibration of the tool will be necessary to ensure that grains are not overloaded; for example, a steel ball pressed into glass will produce a Hertzian fracture, even though it is softer than glass. Other minerals, such as magnetite (Mohs'hardness = 6.5) have been shown to scratch glass ceramics such as Zerodur (Mohs' hardness = 6.5). Thus, minerals can be differentiated: note that regardless of the mineral species, if any particle is harder than 6.5 it will certainly be an interesting discovery for both planetary geology and human exploration concerns. The scratches will be identified using the 6X optical microscope and profiled with the atomic force microscope included in the MECA instrument suite. Analysis of the scratch morphology will yield evidence concerning the shape of the particle responsible for producing each scratch. For example, angular grains should leave vertical cracks with microconchoidal lateral chipping, while rounded grains might leave chattermarks, or nested partial Hertzian cracks. Particle shape can thus be inferred from these indentation modes, as well as material hardness. In addition, particle size information may also be available if pits caused by rolling particles can be identified. Converse to scratching, the minerals may be crushed at their contact points, and be smeared onto the target substrates to leave what geologists refer to as "streaks". These are coldwelded trails of mineral material that have structure and color indicative of mineral composition. The AFM will determine the morphology of these streaks, while the microscope will ascertain the color. On the harder substrates, we might expect streaking to dominate; on the softer substrates, scratching may dominate. Progressions of material interactions across the substrate selection will be a valuable source of data for mineral discrimination. It should also be noted that many minerals have coatings (such as iron oxides), and these will have to be differentiated from the host mineral grains; laboratory tests will establish the effects of such coatings on the scratch results. Finally, we note that the microscope will provide corroborative data regarding likely mineral species by grain shapes, fracture patterns, surface textures, colr, and UV fluorescence reactions.

Kuhlman, K. R.↗
NASA NTRS1999

The Mars Environmental Compatibility Assessment (MECA) Abrasion Tool

The Mars Environmental Compatibility Assessment (MECA) experiment, an instrument suite to be flown on Mars Surveyor 2001, will include a tool for doing simple mineralogical scratch and streak tests on particles from the Martian regolith. The Abrasion Tool will be applied to particles that adhere themselves to highly polished substrates of various hardnesses. Granular soil components will be subjected to a compressive force of about 3 N using a leaf spring. The spring will be applied with a paraffin actuator capable of a 0.76 mm throw to achieve a maximum displacement of about 7.5 mm at the tip of the tool. The pressure per grain will be dependent on the grain size, the number of grains that adhere to the substrate and the number of grains in compression. The pressure per particle is expected to be on the order of 100 MPa - 1 GPa. The MECA sample wheel containing the substrates will be rotated after the particles are placed in compression to produce scratches or pits. A primary goal of the Abrasion Tool is to identify quartz (Mohs' hardness = 7) using substrates of varying hardnesses. Quartz is considered hazardous to future human explorers of Mars because it can cause silicosis of the lungs if it is of respirable size. It is also hazardous to machinery, structures, and space suits because of its ability to abrade and scratch surfaces. Since large quantities of minerals harder than quartz are not expected, any scratches produced on polished quartz substrates might be reasonably attributed to quartz particles, although there may be minerals such as impact metamorphic diamond in the soils. Careful calibration of the tool will be necessary to ensure that grains are not overloaded; for example, a steel ball pressed into glass will produce a Hertzian fracture, even though it is softer than glass. Other minerals, such as magnetite (Mohs' hardness = 6.5) have been shown to scratch glass ceramics such as Zerodur (Mohs' hardness = 6.5). Thus, minerals can be differentiated: note that regardless of the mineral species, if any particle is harder than 6.5 it will certainly be an interesting discovery for both planetary geology and human exploration concerns. The scratches will be identified using the 6X optical microscope and profiled with the atomic force microscope included in the MECA instrument suite. Analysis of the scratch morphology will yield evidence concerning the shape of the particle responsible for producing each scratch. For example, angular grains should leave vertical cracks with microconchoidal lateral chipping, while rounded grains might leave chatter marks, or nested partial Hertzian cracks. Particle shape can thus be inferred from these indentation modes, as well as material hardness. In addition, particle size information may also be available if pits caused by rolling particles can be identified. Converse to scratching, the minerals may be crushed at their contact points, and be smeared onto the target substrates to leave what geologists refer to as "streaks". These are cold-welded trails of mineral material that have structure and color indicative of mineral composition. The AFM will determine the morphology of these streaks, while the microscope will ascertain the color. On the harder substrates, we might expect streaking to dominate; on the softer substrates, scratching may dominate. Progressions of material interactions across the substrate selection will be a valuable source of data for mineral discrimination. It should also be noted that many minerals have coatings (such as iron oxides), and these will have to be differentiated from the host mineral grains; laboratory tests will establish the effects of such coatings on the scratch results. Finally, we note that the microscope will provide corroborative data regarding likely mineral species by grain shapes, fracture patterns, surface textures, color, and UV fluorescence reactions. Additional information is contained in the original extended abstract.

Kuhlman, K. R.↗
NASA NTRS1984

The chemical kinetics and thermodynamics of sodium species in oxygen-rich hydrogen flames

Results are presented which, it is claimed, lead to a correction of previous misconceptions over the relative importance and kinetics of NaO2. It is shown that its rapid conversion to NaO and NaOH is such that it can severely perturb the NaOH/Na ratio and produce significant concentration overshoots over that predicted from the balance of the reaction of Na with H2O. This becomes increasingly the case in flames of large O2 concentrations and temperatures below 2500 K; and the corresponding large rate constants for the termolecular formation of the other alkali peroxides imply that similar considerations will be necessary for them. Depending on the rate constants for the exothermic conversions of MO2 to MO or MOH, the steady-state concentrations of MO2 could be more or less significant than for sodium. Owing to numerous reactions that produce these conversions, the MOH species will probably be the dominant species in all cases in oxygen-rich hydrogen or hydrocarbon flames, with MO concentrations at not greater than 1 percent of the bound metal.

Hynes, A. J.↗
NASA NTRS2000

Efficient, environmentally acceptable method for waterproofing insulation material

A process of waterproofing alumina-rich or silica-rich fibrous thermal insulation material, the process including the steps of: (a) providing an alumina-rich or a silica-rich fibrous material; (b) providing a waterproofing solution including: (1) a carrier solvent selected from the group consisting of aliphatic alcohols having from 1C to 6C, water, and mixtures thereof; and (2) an alkoxysilane defined by the formula R.sub.4-x -Si-(O-R').sub.x where x is 1-3 and R is selected from the group consisting of alkyl groups having from 1C to 10C, hydrogen, or fluorocarbon groups having from 1F to 15F; and where O-R' is an alkoxy group having from 1C to 5C, or a mixture of alkoxysilanes defined by the above formula R.sub.4-x -Si-(O-R').sub.x ; and optionally (3) modifiers including acids, such as acetic acid or nitric acid, or bases, such as ammonium hydroxide, RNH.sub.2, R.sub.2 NH, or R.sub.3 N, or MOH, where R is selected from the group consisting of alkyl groups having from 1C to 10C or hydrogen, and where M=Na, Li, or K; (c) contacting the fibrous material with the waterproofing solution for a sufficient amount of time to waterproof the fibrous material; and (d) curing the coated fibrous material to render it sufficiently waterproof. A chemical solution for waterproofing alumina-rich or silica-rich fibrous thermal insulation materials, the solution including: (a) a carrier solvent selected from the group consisting of aliphatic alcohols having from 1C to 6C, water, and mixtures thereof; and (b) an alkoxysilane defined by the formula R.sub.4-x -Si-(O-R').sub.x where x is 1-3 and R is selected from the group consisting of alkyl groups having from 1C to 10C, hydrogen, or fluorocarbon groups having from 1F to 15F; and where O-R' is an alkoxy group having from 1C to 5C, or a mixture of alkoxysilanes defined by the above formula R.sub.4-x -Si-(O-R').sub.x ; and optionally (c) modifiers including acids, such as acetic acid or nitric acid, or bases, such as ammonium hydroxide, RNH.sub.2, R.sub.2 NH, or R.sub.3 N, or MOH, where R is selected from the group consisting of alkyl groups having from 1C to 10C or hydrogen, and where M=Na, Li, or K.

Blohowiak, Kay Y.↗
NASA NTRS2010

Evidence for Interlayer Collapse of Nontronite on Mars from Laboratory Visible and Near-IR Reflective Spectra

Dioctahedral smectites (e.g., nontronite and montmorillionite) are interpreted to occupy the optical surface of Mars at a number of locations on the basis of spectral features derived from interlayer H2O and MOH (M=Fe(3+)2, Fe(3+)Al, Al2, etc.) as observed by orbiting MRO-CRISM and MEx-OMEGA hyperspectral imaging spectrometers. At wavelengths shorter than approximately 2.7 micrometers, the strongest bands from interlayer H2O occur at approximately 1.4 and 1.9 micrometers from 2v1 and v1+v2, respectively, where v1 and v2 are the fundamental stretching and bending vibrations of the H2O molecule. Smectite MOH vibrations occur near 1.4 micrometers (stretching overtone) and in the region between 2.1 and 2.7 micrometers (stretching + bending combination). Because interlayer H2O can exchange with the martian environment, a number of studies have examined the strength of the interlayer H2O spectral features under Mars-like environmental conditions. The relationship between spectral properties and the underlying crystal structure of the smectites was not determined, and the extent of interlayer H2O removal was not established. We report combined visible and near-IR (VNIR), Mossbauer (MB), and powder X-ray diffraction (XRD) data for samples of the Fe-bearing smectite nontronite where the interlayer was collapsed by complete removal of interlayer H2O.

Morris, Richard V.↗
NASA NTRS1981

Abradable dual-density ceramic turbine seal system

A plasma sprayed dual density ceramic abradable seal system for direct application to the HPT seal shroud of small gas turbine engines. The system concept is based on the thermal barrier coating and depends upon an additional layer of modified density ceramic material adjacent to the gas flow path to provide the desired abradability. This is achieved by codeposition of inert fillers with yttria stabilized zirconia (YSZ) to interrupt the continuity of the zirconia struture. The investigation of a variety of candidate fillers, with hardness values as low as 2 on Moh's scale, led to the conclusion that solid filler materials in combination with a YSZ matrix, regardless of their hardness values, have a propensity for compacting rather than shearing as originally expected. The observed compaction is accompanied by high energy dissipation in the rub interaction, usually resulting in the adhesive transfer of blade material to the stationary seal member. Two YSZ based coating systems which incorported hollow alumino silicate spheres as density reducing agents were surveyed over the entire range of compositions from 100 percent filler to 100 percent YSZ. Abradability and erosion characteristics were determined, hardness and permeability characterized, and engine experience acquired with several system configurations.

Clingman, D. L.↗
NASA NTRS1985

'Diamondlike' carbon films - Optical absorption, dielectric properties, and hardness dependence on deposition parameters

An RF plasma deposition system was used to prepare amorphous 'diamondlike' carbon films. The source gases for the RF system include methane, ethylene, propane, and propylene, and the parameters varied were power, dc substrate bias, and postdeposition anneal temperature. Films were deposited on various substrates. The main diagnostics were optical absorption in the visible and in the infrared, admittance as a function of frequency, hardness, and Auger and ESCA spectroscopy. Band gap is found to depend strongly on RF power level and band gaps up to 2.7 eV and hardness up to 7 Mohs were found. There appears to be an inverse relationship between hardness and optical band gap.

Natarajan, V.↗
NASA NTRSDate not supplied

Removing Contamination from Genesis Sapphire Collectors by Polishing

The Genesis Solar Wind Sample Re-turn Mission used a variety of materials as solar wind (SW) collectors. “Sapphire”, which is single crystal corundum, was ~6.7% of the collector material flown. But, a much higher percentage of Genesis sapphire collectors (SAP) survived the crash of the sample-return capsule as SAP is chemically inert, physically tough, and hard (MOHS 9, by definition). In fact, 39 sapphire fragments of bulk SW collector having areas ≥60 sq mm are available in JSC’s Genesis online catalog, whereas only 1 similarly sized silicon fragment is available (accessed 1/1/2020). In spite of the ease of accessing larger fragments, sapphire has not been popular among Genesis re-searchers because it is an electrical insulator (making SIMS more difficult) and its chemical inertness, high melting point and high hardness precludes the use of many mass-spectroscopic techniques. Recently, as alternative techniques for measuring Genesis samples are developed (e.g., synchrotron TXRF, INAA, laser ablation mass spectroscopy), more researchers are choosing to analyze sapphire. Thus, a number of researchers are actively studying how to best remove contamination from the Genesis sapphire surfaces. This report extends the task in Schmeling et al. that used polishing compounds to remove contamination from Genesis sapphire and focuses on contaminants (welded silicon, aluminum) that current chemical methods find recalcitrant.

M. Schmeling↗
NASA NTRS2024

Removing Contamination From Genesis Sapphire Collectors By Polishing

The Array Collectors of the Genesis spacecraft collected bulk solar wind (SW), as well as three subsets of SW (fast, slow, and coronal mass ejection) in a variety of materials. In all cases the SW implant peaked within < 0.2 microns of the surface. So, when the sample return capsule crashed on landing, cleaning the surfaces for analysis became an extremely difficult, but imperative, task. One collector material was “sapphire”, commercial single crystal corundum. Only ~7.7% of the Genesis Array collectors were sapphire (SAP) but a much higher percentage survived the crash. In fact, surviving bulk SW sapphire collectors have an average area ~10x that of their silicon counterparts since SAP is physically tough, and hard (MOHS 9, by definition) as well as is chemically inert. So, SAP is a good candidate for analytical techniques for measuring SW that require clean areas larger than a millimeter; e.g., synchrotron TXRF and INAA. It is also possible to measure SW in SAP using laser ablation and secondary ion mass spectrometry (SIMS) and, recently, more researchers are choosing to analyze sapphire. Thus, removing surface contamination from SAP could enable many research projects. This report extends the task presented in Schmeling et al. ([4]) that used polishing compounds to remove contamination from Genesis sapphire. It focuses on how polishing with their two top candidates (colloidal silica and cerium oxide) affects the SW layer in SAP.

Genesis solar wind↗
NASA NTRS1991

Higher-order harmonics in electromagnetic scattering from a nonlinear anisotropic cylinder

The general solution of the scattering of harmonic signals, by a medium which has nonlinear constitutive relations, contains higher harmonics. The scattering amplitude consists of the linear component and additional correction terms that depend on the amplitude of the incident wave. In this paper, we examine the effects of nonlinearities on the field components and on the radar cross section at the second and third harmonics.

Hasan, Moh'd A.↗
NASA NTRS2012

Enhanced project management tool

A system for managing a project that includes multiple tasks and a plurality of workers. Input information includes characterizations based upon a human model, a team model and a product model. Periodic reports, such as one or more of a monthly report, a task plan report, a schedule report, a budget report and a risk management report, are generated and made available for display or further analysis or collection into a customized report template. An extensible database allows searching for information based upon context and upon content. Seven different types of project risks are addressed, including non-availability of required skill mix of workers. The system can be configured to exchange data and results with corresponding portions of similar project analyses, and to provide user-specific access to specified information.

Maluf, David A.↗