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Showing 1 to 20 of 101 for “"borohydride"”.
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A comparison of conventional heating techniques and microwave irradiation for the desorption of lithium borohydride and lithium borohydride composites
The desorption of lithium borohydride and lithium borohyride composites was examined using both conventional heating techniques and microwave irradiation. LiBH4 was milled with TiH2 in various molar ratios in an argon atmosphere using both roller and planetary mill techniques. Thermo-gravimetric …
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Mechanisms In the Water Vapor Hydrolysis of Sodium Borohydride
… on demand. Chemical hydrides such as sodium borohydride (NaBH<sub>4</sub>), release hydrogen via exothermic reaction with water as follows: NaBH<sub>4</sub> + (2+x) H<sub>2</sub>O → 4H<sub>2</sub> + NaBO<sub>2</sub>·xH<sub>2</sub>O + heat. The gravimetric and volumetric capacities …
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Destabilization of lithium borohydride with additions of magnesium hydride
It has been shown that lithium borohydride can be destabilized with magnesium hydride additions for the purpose of reversibly hydrogen. In reactive composites of these hydrides alternative chemical pathways become available for dehydrogenation, which can modify both the thermodynamics and kinetics …
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The development of a membraneless direct borohydride alkaline fuel cell
… kinetics over other fuel cell types. The direct borohydride alkaline fuel cell (DBAFC), a derivative of the AFC, can provide increased power output and improved safety features afforded using borohydride in place of hydrogen gas. However, relatively little research has been conducted on DBAFC, …
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Chemical Vapor Deposition of Transition Metal Diborides From Borohydride Precursors
Both HfB2 and CrB2 depositions were highly conformal. For example, a 65 nm wide trench with a 19:1 depth-width aspect ratio was coated uniformly with HfB2. The coverage improved further when an additional flux of a growth suppressor was added during deposition. Super-conformal CrB2 films were …
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ASYMMETRIC REDUCTIONS BY CHIRAL LITHIUM-ALUMINUM HYDRIDE AND POTASSIUM-BOROHYDRIDE REAGENTS
<p>A chiral aminotriol, tris-{(S)-2-hydroxypropyl}amine (1) was synthesized from ammonia and three equivalents of (S)-propylene oxide. The triol was allowed to condense with boric acid to form a bicyclic borate {(S,S,S)-triisopropanolamine borate, 2} which was allowed to react with a suspension of …
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The reduction of organic halides and diazonium salts with sodium borohydride
Sodium borohydride in aqueous dimethylsulfoxide has been shown to be a good reducing agent for converting certain activated aromatic halo-compounds to their corresponding dehalogenated products. The order for ease of removal of the halogen is I>Br>Cl. The activating groups are those that are …
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Coinage metal complexes bearing mono-supported borohydride ligands based on scorpionate scaffolds
Singly supported borohydride ligands, in comparison to scorpionate ligands are scarcely reported within the chemical literature. This thesis looks at select examples of the coordination of such ligands and compares the different supporting scaffolds and structural motifs between these ligands. It …
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Design and performance of a prototype borohydride fuel cell and control system
A direct borohydride fuel cell stack with a novel integrated manifold, along with a control system, was designed, manufactured and studied. Two fuel cell stacks were built and demonstrated. The main objective was to build these stacks to achieve a power level of 100 watts. The control system was …
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Developing Core-Shell Borohydride Nanoarchitectures and Understanding their Structure-Hydrogen Release/Uptake Relationships
… with high density, compactness, and safety. Borohydrides have been extensively investigated as promising candidates for H2 storage; however, the high thermodynamic stability, sluggish H2 release kinetics, and limited H2 reversibility have hampered their practical use. Nanosizing is an …
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Modeling, Analysis and Design of a Regenerative Direct Sodium Borohydride Fuel Cell System
Made available in DSpace on 2017-07-06T18:49:05Z (GMT). No. of bitstreams: 3 Kopec_Grant_M_MS.pdf: 1152173 bytes, checksum: 5f5bc6bf0622231f46fd2c771854a96a (MD5) Kopec_Grant_M_MS_ABS.pdf: 7761 bytes, checksum: f26337585d3b36b9395648a055f107c8 (MD5) license.txt: 4813 bytes, checksum: …
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Volatile metal borohydride complexes: synthesis and characterization of new chemical vapor deposition precursors
The complex sodium methylborohydride, Na(H3BCH3), can be prepared in high yield (83%) by the addition of trimethylboroxine, (H3C)3B3O3, to sodium aluminum hydride, NaAlH4. The subsequent reaction of two equivalents of sodium methylborohydride with the alkaline earth bromides; MgBr2, CaBr2, SrBr2, …
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The sodium borohydride reduction of organic halides and related derivatives in aprotic solvents
Sodium borohydride reduces alkyl halides and their related tosylate derivatives in the order primary > secondary > tertiary, while the relative order of leaving-group ability is Ts⁻ ≥ I⁻ > Br⁻ > > Cl⁻. The yields obtained ranged from 90-100% for most simple, primary and secondary iodides, bromides, …
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Cathode Electrocatalyst Selection and Catalyst Deposition for a Direct Borohydride/Hydrogen Peroxide Fuel Cell
Made available in DSpace on 2017-07-06T18:48:17Z (GMT). No. of bitstreams: 3 Gu_Lifeng_MS.pdf: 1772067 bytes, checksum: 6152bb6d7c88011948e222d3fadd99f3 (MD5) Gu_Lifeng_MS_ABS.pdf: 57407 bytes, checksum: 8d4cb6c31a9f53ba045b5d7503558df2 (MD5) license.txt: 4813 bytes, checksum: …
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Design and Analysis of a Direct Borohydride Fuel Cell DC-DC Converter for Portable Applications
… with gaseous hydrogen as the fuel, the direct borohydride fuel cell (DBFC) is becoming an emerging type of fuel cell. Electrochemistry of DBFC is described in this thesis. V–I characteristics and the equivalent circuit of DBFC are tested and analyzed. A dc-dc boost converter is designed due to …
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Chemical Vapor Deposition of Metal Diboride and Metal Oxide Thin Films From Borohydride-Bonded Precursors
… from a recently developed highly volatile borohydride-bonded Mg precursor, by means of catalyst-enhanced chemical vapor deposition. The films are stoichiometric and highly crystallized, however, the lattice constants shift away from the MgB2 structure to the diboride structure of the …
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High coordination number compounds of thorium borohydride, and of calcium and strontium N,N-dimethylaminodiboranates
… center in this molecule is surrounded by six borohydride ligands. Four of these six borohydrides are coordinated in a tridentate κ3 fashion, and the other two BH4- groups bridge between neighboring Th centers in a bis(bidentate) κ2,κ2 fashion forming a polymeric structure, as determined by …
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The electrolysis of lithium alkyls and ethyl magnesium bromide in lithium borohydride-diethyl ether solutions
… with a simultaneous electrolysis of an alkali borohydride. The deposition of the free alkyl radical in the presence of the borohydride radical may result in a reaction between the two. The purpose of this investigation was to study the electrolysis of diethyl ether solutions of lithium methyl, …
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