Roedderite A new mineral from the Indarch meteorite.
Chemical and mineralogical composition of roedderite found in Indarch meteorite, presenting electron probe analysis and X-ray diffraction pattern optical data
MINERALOGY↗
SEARCH · Engineering Papers
Results for “electronics analysis”
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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Progress in developing high energy nozzle beams.
Electron beam analysis of skimmer influence on nozzle beam formation
RAREFIED GAS DYNAMICS↗
Weight Saving Technology
The airplane shown below is the Beech Super King Air, an executive transport built by Beech Aircraft corporation, Wichita, Kansas. Its development was aided by the NASA computer program known as NASTRAN(Registered TradeMark) (NASA Structural Analysis), which electronically analyzes a computerized design and predicts how it will react to many different conditions of stress and strain. In this instance the program was employed in analysis of the airplane's structure and engine mounts. NASTRAN was similarly used in development of other Beech planes, such as the T-34C military trainer and the new single-engine Skipper light-plane, which is making its debut this year. At its Boulder, Colorado facility, Beech has used NASTRAN in analysis of fuel tanks for space vehicles. The company reports it has achieved cost savings and improved its design/analysis capabilities through use of the NASA program. NASTRAN and other government-generated computer programs are made available to industry through NASA's Computer Software Management and Information Center (COSMIC)(Registered TradeMark) at the University of Georgia.
Source record↗
Numerical analysis of atomic density distribution in arc driven negative ion sources
The purpose of this study is to calculate atomic (H{sup 0}) density distribution in JAEA 10 ampere negative ion source. A collisional radiative model is developed for the calculation of the H{sup 0} density distribution. The non-equilibrium feature of the electron energy distribution function (EEDF), which mainly determines the H{sup 0} production rate, is included by substituting the EEDF calculated from 3D electron transport analysis. In this paper, the H{sup 0} production rate, the ionization rate, and the density distribution in the source chamber are calculated. In the region where high energy electrons exist, the H{sup 0} production and the ionization are enhanced. The calculated H{sup 0} density distribution without the effect of the H{sup 0} transport is relatively small in the upper region. In the next step, the effect should be taken into account to obtain more realistic H{sup 0} distribution.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Optical and chemical analysis of iron in Luna 20 plagioclase.
Review of analytical data on the iron content of Luna 20 anorthitic plagioclase, obtained by a highly sensitive technique for measuring polarized absorption related to crystal-field splittings and by automated electron microprobe analysis of oriented single crystals. The iron content is found to range from a few hundredths to a few tenths of a weight per cent from crystal to crystal. The optical and chemical properties of the iron appear to be caused by postcrystallization migration and exsolution. Postcrystallization effects may obscure evidence of the original oxidation state and iron concentration of these crystals.
Bell, P. M.↗
Analysis of Phase Separation in Czochralski Grown Single Crystal Ilmenite
Ilmenite (FeTiOs) is a wide bandgap semiconductor with an energy gap of 2.58 eV. Ilmenite has properties suited for radiation tolerant applications, as well as a variety of other electronic applications. Single crystal ilmenite has been grown from the melt using the Czochralski method. Growth conditions have a profound effect on the microstructure of the samples. Here we present data from a variety of analytical techniques which indicate that some grown crystals exhibit distinct phase separation during growth. This phase separation is apparent for both post-growth annealed and unannealed samples. Under optical microscopy, there appear two distinct areas forming a matrix with an array of dots on order of 5 pm diameter. While appearing bright in the optical micrograph, atomic force microscope (AFM) shows the dots to be shallow pits on the surface. Magnetic force microscope (MFM) shows the dots to be magnetic. Phase identification via electron microprobe analysis (EMPA) indicates two major phases in the unannealed samples and four in the annealed samples, where the dots appear to be almost pure iron. This is consistent with micrographs taken with a scanning probe microscope used in the magnetic force mode. Samples that do not exhibit the phase separation have little or no discernible magnetic structure detectable by the MFM.
Wilkins, R.↗
Coherent and spontaneous emission in the quantum free electron laser
We present an analysis of quantum free electron laser (QFEL) dynamics including the effects of spontaneous emission. The effects of spontaneous emission are undesirable for coherent short-wave generation using FELs and have been shown in previous studies to limit the capabilities of classical self amplified spontaneous emission (SASE)-FELs at short wavelengths {approx}1 A due to growth of electron beam energy spread. As one of the attractive features of the QFEL is its potential as a relatively compact coherent x-ray source, it is important to understand the role of spontaneous emission, but to date there has not been a model which is capable of consistently describing the dynamics of both coherent FEL emission and incoherent spontaneous emission. In this paper, we present such a model, and use it to show that the limitations imposed by spontaneous emission on coherent FEL operation are significantly different in the quantum regime to those in the classical regime. An example set of parameters constituting a QFEL using electron and laser parameters which satisfy the condition for neglect of spontaneous emission during coherent QFEL emission is presented.
43 PARTICLE ACCELERATORS↗
Total Dose Survivability of Hubble Electronic Components
A total dose analysis for exposure of electronic parts at the box level is presented for the Hubble Space Telescope. This was done using solid angle sectoring/3-dimensional ray trace and Monte Carlo radiation transport simulations. Results are discussed in terms of parts that are potential total dose concerns.
Monte Carlo radiation transport simulation↗
Superparamagnetic Properties and Significant Applications of Iron Oxide Nanoparticles for Astonishing Efficacy—a Review
This paper reviewed the comprehensive literature survey on the physical, chemical, and the catalytic properties and applications of iron oxide nanoparticles. In recent years, iron oxide has made a versatile progress due to its outstanding magnetic property. The average crystallite size was reported in previous literatures in the range of 10–45 nm using Scherrer’s formula. The powder morphology was found to deliberate quasi-spherical and predominantly spherical shape. The specific surface area as measured by N{sub 2} adsorption BET isotherm was reported in the range of 17.6–26.21 m{sup 2}/g. Depending on the synthesis pathway there was, an inverse or normal spinel structure could be achieved. X-ray diffraction analysis revealed the crystallite size in the range between 8 and 42 nm. Fourier transform infrared spectroscopy reported the changes in functional group, stretching vibrations in the iron oxide nanoparticles. Scanning electron microscopy analysis showed most of Fe{sub 3}O{sub 4} nanoparticles were in spherical morphology with the particle size range between 10 and 26 nm. Vibrating sample magnetometer reported the magnetization value for Fe{sub 3}O{sub 4} nanoparticles.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Cu-Ga-Se Thin Films Prepared by a Combination of Electrodeposition and Evaporation Techniques
Cu-Ga-Se thin films were prepared using a combination of electrodeposition and evaporation techniques. A Cu-Se/Mo/glass precursor thin film was first prepared by galvanostatic electrodeposition. On top of this film three different thicknesses of Ga were deposited by evaporation. The Cu-Ga-Se thin films were formed by annealing the Ga/Cu-Se/Mo/glass thin film configuration in a tubular chamber with Se powder, at different temperatures. Thin films were characterized by X-ray diffraction (XRD), photocurrent spectroscopy (PS), inductively coupled plasma (ICP) analysis, and scanning electron microscopy (SEM). The detailed analysis from X-ray reveals that after annealing at 550 C the CuGaSe{sub 2} phase is formed when the thickness of Ga is 0.25 {mu}m, however at 0.5 {mu}m and 1.0 {mu}m Ga the formation of CuGa{sub 3}Se{sub 5} and CuGa{sub 5}Se{sub 8} phases is observed respectively. Band gap values were obtained using photocurrent spectroscopy.
14 SOLAR ENERGY↗
Surface defects on the Gd{sub 2}Zr{sub 2}O{sub 7} oxide films grown on textured NiW technical substrates by chemical solution method
Epitaxial growth of oxide thin films has attracted much interest because of their broad applications in various fields. In this study, we investigated the microstructure of textured Gd{sub 2}Zr{sub 2}O{sub 7} films grown on (001)〈100〉 orientated NiW alloy substrates by a chemical solution deposition (CSD) method. The aging effect of precursor solution on defect formation was thoroughly investigated. A slight difference was observed between the as-obtained and aged precursor solutions with respect to the phase purity and global texture of films prepared using these solutions. However, the surface morphologies are different, i.e., some regular-shaped regions (mainly hexagonal or dodecagonal) were observed on the film prepared using the as-obtained precursor, whereas the film prepared using the aged precursor exhibits a homogeneous structure. Electron backscatter diffraction and scanning electron microscopy analyses showed that the Gd{sub 2}Zr{sub 2}O{sub 7} grains present within the regular-shaped regions are polycrystalline, whereas those present in the surrounding are epitaxial. Some polycrystalline regions ranging from several micrometers to several tens of micrometers grew across the NiW grain boundaries underneath. To understand this phenomenon, the properties of the precursors and corresponding xerogel were studied by Fourier transform infrared spectroscopy and coupled thermogravimetry/differential thermal analysis. The results showed that both the solutions mainly contain small Gd−Zr−O clusters obtained by the reaction of zirconium acetylacetonate with propionic acid during the precursor synthesis. The regular-shaped regions were probably formed by large Gd−Zr−O frameworks with a metastable structure in the solution with limited aging time. This study demonstrates the importance of the precise control of chemical reaction path to enhance the stability and homogeneity of the precursors of the CSD route. - Highlights: •We investigate microstructure of Gd{sub 2}Zr{sub 2}O{sub 7} films grown by a chemical solution route. •The aging effect of precursor solution on formation of surface defect was thoroughly studied. •Gd−Zr−O clusters are present in the precursor solutions.
36 MATERIALS SCIENCE↗
libwfa: Wavefunction analysis tools for excited and open‐shell electronic states
Abstract An open‐source software library for wavefunction analysis, libwfa, provides a comprehensive and flexible toolbox for post‐processing excited‐state calculations, featuring a hierarchy of interconnected visual and quantitative analysis methods. These tools afford compact graphical representations of various excited‐state processes, provide detailed insight into electronic structure, and are suitable for automated processing of large data sets. The analysis is based on reduced quantities, such as state and transition density matrices (DMs), and allows one to distill simple molecular orbital pictures of physical phenomena from intricate correlated wavefunctions. The implemented descriptors provide a rigorous link between many‐body wavefunctions and intuitive physical and chemical models, for example, exciton binding, double excitations, orbital relaxation, and polyradical character. A broad range of quantum‐chemical methods is interfaced with libwfa via a uniform interface layer in the form of DMs. This contribution reviews the structure of libwfa and highlights its capabilities by several representative use cases. This article is categorized under: Software > Quantum Chemistry Theoretical and Physical Chemistry > Spectroscopy
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Microstructure and Phase Composition of Ni-Based Alloy Obtained by High-Speed Direct Laser Deposition
Phase composition and structural features of nickel-based alloy EP741 obtained by high-speed direct laser deposition were discussed in the paper. The technology of high-speed direct laser deposition has been successfully applied during the formation of samples with the various operating parameters of the experimental device. The laser power was between 450 and 1200 W, the scanning speed was 1.2 mm/s, the powder feed rate was 45 g/min, and the laser beam diameter was 1.2 mm. The structure and phase composition of the initial material and as-deposited samples were studied using optical and scanning electron microscopy, x-ray analysis and transmission electron microscopy. The investigation has shown that spherical particles of powder (EP741) can be used to form products by additive manufacturing with the presence of additional heat treatment, since almost all the as-deposited samples obtained do not contain cracks, and large volume of pores was observed only in the sample obtained with the power of 450 W. In addition, the phase composition of the as-deposited samples showed a high content of precipitating phase Ni{sub 3}(Al, Ti) in matrix, which is coherent to the solid solution based on nickel. In theory, the presence of Ni{sub 3}(Al, Ti) phase corresponds to the heat-treated nickel-base alloy obtained by standard methods of processing.
36 MATERIALS SCIENCE↗
Effect of Preheating and Water Cooling on the Performance of Friction-Stir-Welded Aviation-Grade Aluminum Alloy Joints
This paper examined the effect of preheating and water cooling on the thermal, mechanical, metallurgical, and texture properties of friction-stir-welded AA6082. Joints are fabricated under different preheating (FSW-P) and water cooling (FSW-C) conditions. The experimental outcomes indicate that the preheating and water cooling enhance the mechanical properties of the joint. The maximum tensile strength of 295 MPa is obtained for FSW-P1. It is also observed that preheating has more impact on microhardness. Microstructural analysis using optical microscope and electron backscatter diffraction analysis indicated that FSW produced fine equiaxed grains in the nugget zone due to dynamic recrystallization. Texture analysis shows that finer grain grains are obtained under preheating and water cooling conditions. The minimum grain size of 5.3 µm is obtained under FSW-P1. X-ray diffraction analysis shows that Mg{sub 2}Si phase in nugget zone that is an indication of dissolution and formation of strengthening precipitates. Fracture analysis indicates that preheating also improves the ductility of the joint.
36 MATERIALS SCIENCE↗
Study on dielectric behavior and harvesting properties of new Ba0.5Sr0.4Ca0.1TiO3/poly(ether imide) composite films
Highlights: • 1% Nb{sub 2}O{sub 5} doped Ba{sub 0.5}Sr{sub 0.4}Ca{sub 0.1}TiO{sub 3} particles (BST) were prepared and characterized. • BST/poly(ether imide) composite films were prepared. • The composite films were flexible and exhibited high thermal stability. • The dielectric constant values of the films increased by introducing BST particles. • The films exhibit the ability to generate electrical energy from mechanical one. - Abstract: Barium strontium titanate particles with composition of Ba{sub 0.5}Sr{sub 0.4}Ca{sub 0.1}TiO{sub 3} were prepared by sol-gel method and doped with 1% Nb{sub 2}O{sub 5}. Poly(ether imide) composite films were obtained by mixing particles into a poly(amic acid) solution and casting onto glass plates followed by thermal treatment. The films were investigated by Fourier transform of infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and broadband dielectric spectroscopy. They exhibited good thermal stability having the initial decomposition temperature above 773 K. The dielectric constant was in the range of 3.08–4.17 (room temperature and 1 kHz), and the dielectric loss maintained low values over a large interval of frequency and temperature. The subglass transitions γ and β, the α-relaxation corresponding to the glass transition and the conductivity process of the composite films were evidenced and correlated with the particle content. The ability to generate electrical energy on mechanical impulse was also evaluated.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
The impact of inverse photoemission spectroscopy measurements on regioregular poly(3-hexylthiophene) films
Inverse photoemission spectroscopy (IPES) enables the characterization of the density of states of unoccupied energy states above the Fermi level. However, due to the relatively high electron currents required to achieve useful signal to noise ratios, sample damage is a concern. Regioregular poly(3-hexylthiophene) (rr-P3HT) was used to systematically study the influence of electron radiation during IPES measurements on a prototypical conductive polymer. A series of IPES measurements exposing the samples to a range of electron fluxes was performed. An analysis of the electronic structure and the morphology showed that significant changes occurred in the investigated samples depending on the electron flux. X-ray diffraction results revealed that the root cause of the spectral changes is most likely related to crystallization of the film in an edge-on orientation. This was confirmed by Raman spectroscopy where both the C-C and C=C stretch modes shifted to lower frequencies after 5 IPES scans indicating a more ordered molecular structure. The observation of these stretch modes even after exposure to higher electron flux indicates that the main chemical structure of the P3HT molecules remains mostly intact during the IPES measurements. The absence of significant changes in C 1s and S 2p photoemission core level lines also confirmed this conclusion.
36 MATERIALS SCIENCE↗
The effects of carbonaceous inclusions and their distributions on dynamic failure processes in boron carbide ceramics
Commercially available boron carbide ceramics typically have heterogeneous microstructures that contain distributions of processing-induced inclusions. The inclusions that are rich in carbon (i.e., carbonaceous) govern the underlying mechanisms of brittle fracture through wing crack formation, and thus dictate the mechanical response of the ceramic. In this study, we investigate the dynamic failure of five boron carbide ceramic materials with different inclusion populations. All of the materials were prepared by hot-pressing; four of these boron carbides contained different sizes and concentrations of carbonaceous inclusions, while one contained no carbonaceous inclusions. The heterogeneity distributions were characterized in some detail for statistical analysis using scanning electron microscopy and quantitative image analysis. A modified compression Kolsky bar setup with in situ ultra-high-speed microscopic imaging (10 million frames per second) was then used to study the influence of the inclusion distributions on the dynamic failure processes in these materials, at nominal high strain rates of 10 2 -10 3 s -1 . The in situ ultra-high-speed microscopy highlighted the link between micro and macroscale failure processes and demonstrated that the carbonaceous inclusions are indeed the preferential sites for nucleation of wing cracks, as previously hypothesized based on post-mortem observations. The relative orientation of an inclusion with respect to the compression axis was shown to affect the likelihood that it would participate in crack nucleation. In conclusion, all of the ceramics were also found to have orientation-dependent peak compressive stress, regardless of the presence of carbonaceous inclusions, suggesting that grain orientation distributions are also important.
36 MATERIALS SCIENCE↗