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Showing 1 to 20 of 29 for “"boron carbide"”.
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Processing of nano-sized boron carbide powder
Recent studies indicate B4C nanopowder may provide additional advantages without loss of established properties. In this study, preliminary forms of graphite-coated B4C nanopowders on the order of 20-40 nm with various additives were sintered and analyzed. Methanol washing was performed on the …
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The Electroanalytical Utility of Boron Carbide Electrodes
Made available in DSpace on 2014-12-09T17:35:49Z (GMT). No. of bitstreams: 1 6801706.pdf: 2579901 bytes, checksum: 825e55b8f5b0f623d2393fa4662c140c (MD5) Previous issue date: 1967
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The Transmission of Neutrons in Boron Carbide Spheres
Made available in DSpace on 2017-07-06T18:56:17Z (GMT). No. of bitstreams: 3 Shaban_Yasser_R_MS.pdf: 38862818 bytes, checksum: 9247f708e35d8b79fb4c8937914af4af (MD5) Shaban_Yasser_R_MS_ABS.pdf: 520862 bytes, checksum: 25257165f92de5f7e5c3da7861dba74b (MD5) license.txt: 4813 bytes, checksum: …
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Processability of Nickel-Boron Nanolayer Coated Boron Carbide
This dissertation work focuses on the processability improvement of B4C, especially the compaction and sintering improvement of B4C by applying a Ni-B nanolayer coating on individual B4C particles. A modified electroless coating procedure was proposed and employed to coat nanometer Ni-B layer onto …
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Silane Surface Modification of Boron Carbide in Epoxy Composites
Boron carbide (BC) is used as a radiation absorber in the nuclear industry and particle physics experimentation. BC parts are generally manufactured through a sintering process, which limits the size and shape of components and imparts high cost. On the other hand, a polymeric matrix composite …
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Processing and characterization of boron carbide-hafnium diboride ceramics
… nuclear reactor components. The effectiveness of boron carbide and carbon as HfB₂ sintering additives was systematically evaluated. In the first stage of the research, boron carbide and carbon additives were found to improve the densification behavior of milled HfB₂ powder in part by removing …
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The Formation and Reactivity of BORON CARBIDE and related materials
The formation of boron carbide, (CBC)+B110C;(B4C) is re-viewed with special reference to newer production methods and fabrication techniques. Its crystal structure and the nature of its bonding are discussed in relation to those of other borides and carbides. Information so far available on the …
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Amorphous hydrogenated boron carbide for solid-state direct-conversion thermal neutron detection
Amorphous hydrogenated boron carbide (a-BC:H) is one of a very limited number of neutron-sensitive materials. It has been studied over the last three decades for solid-state thermal neutron detection due to its high resistivity, moderate bandgap, high neutron absorption cross-section, and high …
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The Bulk and Interfacial Electronic and Chemical Structure of Amorphous Hydrogenated Boron Carbide
… interface and bulk of amorphous hydrogenated boron carbide (a-BxC:Hy), is of interest in neutron detection and microelectronics. This dissertation investigates the chemical and electronic structure of semiconducting thin-film a-BxC:Hy grown by plasma enhanced chemical vapor deposition (PECVD) …
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I. Electrochemistry of Mercuric Sulfide Coated Electrodes. Ii. Electrochemical Behavior of Boron Carbide
Made available in DSpace on 2014-12-09T17:36:10Z (GMT). No. of bitstreams: 1 6910655.pdf: 2877976 bytes, checksum: 12f898780d546a2d74e7fda316f11f12 (MD5) Previous issue date: 1968
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Plasma-enhanced molecular layer deposition (PEMLD) of boron carbide dielectrics from carboranes for interconnect and patterning applications
… molecular layer deposition (PEMLD) process for boron carbide from carboranes. This novel method will allow for the deposition of thin films of boron carbide with molecular-level control. Boron carbide, which lies outside the silicon class of materials, has appealing chemical, mechanical, …
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Ab initio calculations of mechanical, thermodynamic and electronic structure properties of mullite, Iota-alumina and boron carbide
… compared it with those of α-Al₂O₃ and γ-Al₂O₃. Boron carbide (B₄C) undergoes an amorphization under high velocity impacts. The mechanism of amorphization is not clear. Ab initio methods are used to carry out largescale uniaxial compression simulations on two polytypes of stoichiometric boron …
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Radiation shielding calculations by means of MCNPX
… materials such as iron, paraffin wax containing boron carbide for the attenuation of neutrons, and lastly, lead as an outer photon shield layer. The thickness of lead necessary to attenuate photons transmitted from the neutron capture reactions and those from the decay of the residual nuclei was …
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Nuclear reaction analysis cross-sections measurements for Boron and Carbon.
… for selected light elements such as Boron and Carbon for the database at Radiation Utilisation Group of Necsa. Deuteron-fnduced and "He-induced reactions were performed at the 4MV Van de Graaff accelerator at detection angles of 0= 150cand 135° for incident beam energies between 1.8 …
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Investigation of electrophoretic deposition as a fabrication technique for high performance composites
… for experiment parameters. Two sample materials, boron carbide and silicon dioxide, are deposited within and on commercially available porous stainless steel filter discs using constant voltage DC EPD. Surfaces are characterized using a scanning electron microscope (SEM) and energetic dispersive …
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Implementation of Solution and Solid Sate Nuclear Magnetic Resonance (NMR) Spectroscopic Techniques for Quantitative and Qualitative Analysis of Molecular Species
… using a solution state quantitative boron nuclear magnetic resonance (11B qNMR) method is presented. The method was validated according to International Conference on Harmonization (ICH) guidelines. Therefore, several analytical performance parameters were discussed such as limit of …
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Solid fuel ramjet infrared signature
… HTPB, and HTPB with aluminum, silicon, boron carbide, and/or magnesium. They were tested at chamber pressures of 80-170 psia and with equivalence ratios between 0.3 and 1.4. With the plume emissivity set to 1.0, plume irradiance was found to increase approximately with the second power …
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Electronic Structure of Three Center Two Electron Bonds in Boron Rich Materials: A Study of Molecules, Crystals, and Amorphous Solids using the ab initio Orthogonalized Linear Combination of Atomic Orbitals Method
… that isomers of carborane, α and β rhombohedral boron, α and β tetragonal boron, γ boron, and boron carbide tend to form icosahedral structures. If the icosahedra were formed with pure boron, it has been demonstrated that there is an insufficient number of electrons to populate all the molecular …
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Transport Characteristics of Amorphous Semiconductors in the Dilute Carrier Regime: A Variable Range Hopping Treatment
… and apply it to a specific case of amorphous boron carbide, where positional disorder is introduced by incorporating random shifts in the positions and orientations of icosahedral clusters of boron and carbon atoms in an initially pristine rhombohedral arrangement of icosahedra. We find the …
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COLD SPRAYED COATINGS WITH DUAL NANOPARTICLE REINFORCEMENTS FOR WEAR AND CORROSION PROTECTION
… substrate as a cold sprayed coating. Using nano-boron carbide (nB4C) and boron nitride nanoplatelets (BNNP) at various combinations up to 2 vol%, an increase of 11.59% in hardness from the control was achieved. Wear testing of each coating was performed, but most of the tests drove through the …
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