Search results for " vanadium"
showing 6 items of 16 documents
Beta decay half-lives of neutron rich Ti–Co isotopes around
1999
Abstract The neutron-rich 57 – 59 Ti, 59 – 62 V, 61 – 64 Cr, 63 – 66 Mn, 65 – 68 Fe, 67 – 70 Co have been produced at GANIL via interactions of a 60.4 MeV/u 86 Kr 34+ with a 58 Ni target. They have been separated by the doubly achromatic spectrometer LISE3. Beta-decay half-lives have been determined for all produced nuclei, and subsequent γ -rays have been observed for the most efficiently produced nuclei. The measured half-lives of vanadium and chromium isotopes are compared to QRPA calculations using ground states deformations from the FRDM or ETFSI models. In an astrophysical context, the short half-lives of 58 Ti and 64 Cr indicate that these nuclei are potential r-process progenitors, …
Vanadium dioxide and gold nanocomposite films for glazing application
2009
Vanadium dioxide is a material with great potential as an intelligent glazing material. The technology is based on a metal to semiconductor transition (MST) where there is an associated structural change from the higher temperature rutile structure to the lower temperature monoclinic structure. This structural transition results in significant changes in optical properties and electrical conductivity. Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised, to produce thin films of gold nano-particle vanadium dioxide nanocomposites. Good surface coverage is observed comparable to that of APCVD processes and a variety of different film thickn…
Investigation on lithium/polymer electrolyte interface for high performance lithium rechargeable batteries
1997
Abstract Performance data of several linear and cross-linked polymer electrolytes are reported and the electrochemical criteria for the selection of electrolytes to be used in electric vehicle lithium metal batteries are discussed. Further, laboratory lithium cells with LiMn2O4 composite cathode were tested to ascertain the effective viability of these polymer in solid-state batteries and preliminary results are reported. This study clearly demonstrates the importance of a broad-based electrochemical characterization in selecting an electrolyte for lithium metal batteries.
Naturally Occurring Oxazole Structural Units as Ligands of Vanadium Catalysts for Ethylene-Norbornene (Co)polymerization
2021
1,3-Oxazole and 4,5-dihydro-1,3-oxazole are common structural motifs in naturally occurring peptides. A series of vanadium complexes were synthesized using VCl3(THF)3 and methyl substituted (4,5-dihydro-1,3-oxazol-2-yl)-1,3-oxazoles as ligands and analyzed using NMR and MS methods. The complexes were found to be active catalysts both in ethylene polymerization and ethylene-norbornene copolymerization. The position of methyl substituent in the ligand has considerable impact on the performance of (co)polymerization reaction, as well as on the microstructure, and thus physical properties of the obtained copolymers.
Rainwater-induced leaching of selenium, arsenic and vanadium from Etnean volcanic soils
2009
Active volcanoes emit considerable amounts of contaminants such as As, Se and V. Mount Etna is the biggest volcano of Europe and an excellent geochemical site to study water-soil processes. Due to its volcanic activity, the rainwater has a strong compositional gradient, both in time and space. At present, the behaviour of trace elements in the soils around Mt Etna is poorly understood. To determine the influence of the rainwater pH on the potential mobilization of geogenic pollutants, batch experiments have been performed with synthetic rainwater for 25 soils collected along the flanks of the volcano. Our results show that: i) The maximum concentrations in the leaching solutions are higher …
Silica powder obtained by sol-gel method as a support of organometallic vanadium catalyst for ethylene polymerization
2004
Sol-gel technique was employed to obtain the silica-type powder, which after modification procedure was applied as asupport of organometallic catalytic system for ethylene polymerization. The powder product was synthesized using hydrolysis and condensation of TEOS, catalyzed by ammonia. Obtained material and a reference support (commercial silica Davisil) were characterized to determine their particle size distributions, BET surface area, pore volume and diameter. Gas-phase adsorption of vanadium catalyst on analyzed support materials as well as adsorption from the solution in hexane were carried out. Both carrier materials were thermally pretreated prior catalytic systems syntheses and the…