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Showing 1 to 15 of 15 for “"SPEX"”.
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Determination of Phase Fraction, Lattice Parameters and Crystallite Size in Mechanically Alloyed Fe-Ni Powders
… Pure Fe-Ni samples were ball milled in a SPEX 8000 shaker mill at liquid nitrogen temperature. X-ray diffractometry was used to determine the phase fractions of the bcc and fcc phases in the alloys and to determine the lattice parameters and crystallite size. The main objective of this …
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Synthesis and Characterization of Aluminum-Carbon Nanotube Composite by Cryogenic Milling
… ranging between six and 90 minutes using a SPEX 6870 Freezer/Mill. Composition and properties of the Al-CNT composite was studied using X-ray diffraction, optical microscopy, nanoindentation, scanning electron microscopy (SEM), Raman spectroscopy, and laser diffraction particle size analysis.
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Near-Infrared Spectroscopy of Near-Earth Asteroids: 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan
… (LXD) spectra of these four asteroids with SpeX mode. The measured spectra wavelength ranged from 1.67-4.2 μm, which includes the 3-μm feature attributed to water/hydroxyl. The 3μm spectral feature was found on Florence, but not on 2004 BL86; meanwhile, the Ganymed and Magellan results were …
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Analysis of Crystalline Phasesby X-Ray Diffraction Effect of Sample Grinding
… (63 micron) sieve. The samples were ground in a Spex Mixer Mill from 5 to 60 minutes, packed into side drift plates, and analyzed using a Philips x-ray diffractometer. The computer software programs, Jade and Micro-ID, were used to analyze the XRD data.</p> <p>The highest intensity peak of …
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Distribution of olivine and pyroxene in S-type asteroids throughout the inner main belt
… and Binzel, 2002) and using the low-resolution SpeX spectrograph (Rayner, 2003) at NASA's Infrared Telescope Facility (IRTF). Here we present a methodology for calculating the location of the 1-micron band center wavelength and BAR with appropriate 1- sigma uncertainties. This method was used to …
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Processing, Microstructural And Mechanical Characterization Of Mechanically Alloyed Al-al2o3 Nanocomposites
… which was achieved on milling for 24 h in a SPEX mill or 100 h in a Fritsch Pulverisette planetary ball mill. The powders were consolidated in two stages: pre-compaction at room temperature followed by vacuum hot pressing (VHP) or hot isostatic pressing (HIP) techniques to a fully dense …
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Structural Evolution In Mechanically Alloyed Fe-based Powder Systems
… were subjected to mechanical alloying in a SPEX 8000 mixer mill. X-ray diffraction technique was employed to study the phase evolution, crystallite size, lattice strain and also to determine the crystal structure(s) of the phases. Depending on the milling time, formation of supersaturated …
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Microstructural And Mechanical Characterization Of Al-al2o3 Nanocomposites Synthesized By High-energy Milling
… with a ball-to-powder weight ratio of 10:1 in a SPEX mill. The uniform distribution of Al2O3 in the Al matrix was confirmed by characterizing these nanocomposite powders by scanning electron microscopy and X-ray mapping. The energy dispersive spectroscopy and X-ray diffraction techniques were …
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Modeling and Synthesis of a Piezoelectric Ceramic-Reinforced Metal Matrix Composite
… powders were combined stoichiometrically in a SPEX milling vial utilizing a charge ratio of 4:1 and subsequently milled for 24 hours. Separate composite powder samples were then annealed in a hydrogen tube furnace at 400°C, 500°C, and 600°C for one and five hours at each temperature. X-ray …
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On a Bimodal Distribution of Grain Size in Mechanically Alloyed Bulk Tungsten Heavy Alloys
… W and Ni powders were mechanically alloyed in a SPEX mill with WC grinding media for durations ranging from 5 to 50 hours, then compacted samples were sintered in hydrogen to generate bulk tungsten heavy alloys with 2, 4 and 6 wt.% Ni. Evidence of a bimodal grain size distribution was seen in …
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The Effect of Milling Time on the Structure and the Properties of Mechanically Alloyed High Carbon Iron-Carbon Alloys
… 6.67 wt.% pre-milled graphite were milled in a SPEX mill with tungsten milling media for up to 100h. The milled powders were then cold-compacted and pressure-less sintered between 900°C and 1200°C for 1h and 5h followed by furnace cooling. Milled powders and sintered samples were characterized …
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Microstructural Engineering of Titanium-Cellulose Nanocrystals Alloys via Mechanical Alloying and Powder Processing
… cost of production. Vibrational milling using a SPEX 8000M mill was used to mechanically alloy titanium powder with varying concentrations of CNCs. Additionally, the milling time was varied. This process showed that varying the concentrations of CNCs between 0.5% - 2% by weight did not noticeably …
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Tracing meteorite source regions through asteroid spectroscopy
… (RELAB) database and the NEO data from the SpeX instrument on the NASA Infrared Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-micron and 2-micron geometric band centers and their …
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Rhenium, osmium and iridium diborides by mechanochemistry: Synthesis, structure, thermal stability and mechanical properties
… crystalline Re and amorphous B powders in the SPEX 8000 high energy ball mill for 80 hours. The formation of boron and perrhenic acids are also reported after ReB2 powder was exposed to the moist air environment for a twelve month period of time. Hexagonal osmium diboride (h-OsB2), a …
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All-electron GW calculations for perovskite transition metal oxides
Ever since the middle of the 1920s, when compounds from the perovskite structure family played a key role in the groundbreaking work of Goldschmidt on material synthesis, perovskite transition-metal oxides (TMOs) have repeatedly stimulated new activities in fundamental research as well as in the …