Application of vanadium incorporated phosphomolybdate supported on the modified kaolinin synthesis of diphenyl carbonate by oxidative carbonylation with phenol

Directory of Open Access Journals (Sweden)

Peng Meng

2017-01-01

Full Text Available Keggin-type molybdophosphoric acid, molybdophosphoric salt and vanadium incorporated molybdophosphoric salt supported on the modified kaolin (MK were investigated as redox co-catalysts for the oxidative carbonylation of phenol to diphenyl carbonate (DPC in the absence of solvent. The 20 wt.% of MnAMPV5 (one kind of vanadium incorporated molybdophosphoric salt loaded on MK showed the highest catalytic activity with the yield of 24.68% and a TON of 306, while the selectivity amounts to nearly 100% in all the carbonylation reactions. The catalysts were characterized by XRD, BET, XPS and H2-TPR. The reusability study showed that the catalysts were stable and active.

Vanadium - 1977

International Nuclear Information System (INIS)

Broderick, G.N.

1977-01-01

This report, with pertinent references, is a comprehensive description and analysis of the vanadium industry. Included is information on industry structure, size and organization; definitions, grades, and specifications; reserves and resources; geology; production and capacity; uses; technology; byproducts and coproducts; strategic considerations; economic and operating factors and problems; supply-demand relationships; and forecasts of supply and demand. Vanadium is used principally as an alloy in steel. Other important uses are in titanium alloys and in various chemical catalytic processes. The world supply of vanadium is sufficient to last far beyond the year 2000 at the present and projected rates of consumption. Almost all of the resources will economically yield vanadium only in conjunction with a coproduct

Physicochemical properties of vanadium impregnated Al-PILCs: Effect of vanadium source

Energy Technology Data Exchange (ETDEWEB)

Balci, Suna, E-mail: sunabalci@gazi.edu.tr; Tecimer, Aylin

2015-03-01

Graphical abstract: - Highlights: • Vanadium was incorporated into Al-PILC using NaVO{sub 3} or VOSO{sub 4}·3H{sub 2}O precursors by wet impregnation, washing after wet impregnation and impregnation from solution methods. • The layered structure of the supports was retained after the vanadium incorporation. • Incorporation took place both by settling and ion exchange mechanism with the treatment VOSO{sub 4}·3H{sub 2}O precursor while settling was dominant in the use of NaVO{sub 3} precursor. • Treatment with VOSO{sub 4}·3H{sub 2}O which was acidic in solution resulted in more structural deformation. • V{sub 2}O{sub 5} and VO{sub 2} were found as the major oxide forms on the impregnated samples. Loading of vanadyl sulfate hydrate (VOSO{sub 4}·H{sub 2}O) resulted in higher V/Si ratio. Most of the vanadium was bonded in +5 oxide form. • Changes in the FTIR signals after vanadium incorporation caused by Brønsted and Lewis sites, silanol, water and vanadium vibrations were occured. • Dehydroxylation of the structure took place around 300 °C. Samples obtained by impregnation and washing after wet impregnation methods resulted in similar mass losses and the wet impregnated sample showed the highest mass loss among the impregnated samples. - Summary: Clay from the Middle Anatolian previously pillared by Al{sub 13}-Keggin ions and then calcined at 300 °C (Al-PILC) was impregnated with aqueous solutions of vanadium precursors by impregnation from solution (I), wet impregnation (WI) and washing after wet impregnation (WWI) methods. The crystal and textural properties were evaluated by X-ray powder diffraction (XRD), nitrogen sorption and transmission electron microscopy (TEM) images. Vanadium incorporation into the Al-PILC resulted decreases in the basal spacing from 1.75 nm to 1.35 nm with the preserved typical layered structure. The use of sodium metavanadate (NaVO{sub 3}) as the source and the impregnation from solution as the incorporation method

Heterogeneous catalysis in the liquid-phase oxidation of olefins--3. The activity of supported vanadium-chromium binary oxide catalyst for the oxidation of cyclohexene

Energy Technology Data Exchange (ETDEWEB)

Takehira, K; Hayakawa, T; Ishikawa, T

1979-03-01

The activity of supported vanadium-chromium binary oxide catalyst for the oxidation of cyclohexene to 1-cyclohexenyl hydroperoxide, 2-cyclohexene-1-one, 2-cyclohexene-1-ol, and cyclohexene oxide was due to the interaction between the metal oxides and the carriers. The oxidation reaction was carried out in benzene at 60/sup 0/C for four hours with the binary oxide supported on (GAMMA)-alumina or silica; three series of catalysts were prepared by combining the vanadium and chromium oxide components with alumina hydrate or silica sol by a kneading method. The silica-supported catalysts had the greatest activity, the highest being the V/sub 2/O/sub 5//SiO/sub 2/ system, which lost its activity quickly during the reaction. This was followed in activity by the Cr/sub 2/O/sub 3//SiO/sub 2/ system, containing the chromium(V) species. The Cr/sub 2/O/sub 3//Al/sub 2/O/sub 3/ system also had high activity and the chromium(V) species. The vanadium and chromium metal ions are probably coordinated tetrahedrally on the support, and these complexes catalyze cyclohexene autoxidation by decomposing 1-cyclohexenyl hydroperoxide.

[Spectralsignatures of nickel and vanadium supported photocatalysts and their photocatalytic properties].

Science.gov (United States)

Hai, Feng; Zhang, Qian-Cheng; Wang, Zhi-Wei; Jian, Li

2011-04-01

Using SiO2, activated carbon (AC) and Al2O3 as supports, the supported photocatalysts Ni-V-O/SiO2, Ni-V-O/AC and Ni-V-O/Al2O3 were prepared by impregnation method, and their spectralsignatures were investigated. The carbonylation of methanol with CO2 under UV irradiation was used as a probe reaction to compare the photocatalytic performance of the prepared catalysts. Integrated with the testing results of carbonylation, the effects of different supports on selectivity for the carbonylation products of methyl formate (MF) and dimethyl carbonate (DMC) were discussed by pyridine-IR and UV-Vis techniques. XRD results showed that the particles of nickel and vanadium supported on SiO2 had the highest degree of dispersion. Results of pyridine-IR indicated that all catalysts retained Lewis acid sites. The acid strength was different from catalyst samples with different supports but with the same active components. The acid strengths could be arranged as follows: Ni-V-O/SiO2 > Ni-V-O/Al2 O3 > Ni-V-O/AC. Different acid strengths exhibited different influence on the selectivity of products MF and DMC of carbonylation. The surface acid strengths of catalysts were the major factor influencing the selectivity of carbonylation products.

Leaching characteristics of vanadium in mine tailings and soils near a vanadium titanomagnetite mining site

Energy Technology Data Exchange (ETDEWEB)

Yang, Jinyan; Tang, Ya; Yang, Kai [College of Architecture and Environment, Sichuan University, Chengdu 610065 (China); Rouff, Ashaki A. [School of Earth and Environmental Sciences, Queens College City University of New York, 65-30 Kissena Boulevard, Flushing, NY 11367 (United States); Elzinga, Evert J. [Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ (United States); Huang, Jen-How, E-mail: jen-how.huang@unibas.ch [Institute of Environmental Geosciences, University of Basel, CH-4056 Basel (Switzerland)

2014-01-15

Highlights: • Vanadium in the soil and mine tailings has low solubility. • The leachability of vanadium in the mine tailings is lower than in the soil. • Low risk of vanadium migrating from the soil and mine tailings into the surrounding environment. • Drought and rewetting increase vanadium release from the soil and mine tailings. • Soil leaching processes control vanadium transport in soils overlain with mine tailings. -- Abstract: A series of column leaching experiments were performed to understand the leaching behaviour and the potential environmental risk of vanadium in a Panzhihua soil and vanadium titanomagnetite mine tailings. Results from sequential extraction experiments indicated that the mobility of vanadium in both the soil and the mine tailings was low, with <1% of the total vanadium readily mobilised. Column experiments revealed that only <0.1% of vanadium in the soil and mine tailing was leachable. The vanadium concentrations in the soil leachates did not vary considerably, but decreased with the leachate volume in the mine tailing leachates. This suggests that there was a smaller pool of leachable vanadium in the mine tailings compared to that in the soil. Drought and rewetting increased the vanadium concentrations in the soil and mine tailing leachates from 20 μg L{sup −1} to 50–90 μg L{sup −1}, indicating the potential for high vanadium release following periods of drought. Experiments with soil columns overlain with 4, 8 and 20% volume mine tailings/volume soil exhibited very similar vanadium leaching behaviour. These results suggest that the transport of vanadium to the subsurface is controlled primarily by the leaching processes occurring in soils.

Supported Vanadium Oxide Catalysts: Quantitative Spectroscopy, Preferential Adsorption of V^4+/5+, and Al2O3 Coating of Zeolite Y

NARCIS (Netherlands)

Catana, Gabriela; Rao, R.R.; Weckhuysen, B.M.; Voort, Pascal van der; Vansant, Etienne; Schoonheydt, R.A.

1998-01-01

A series of supported vanadium oxide catalysts were prepared by the incipient wetness method as a function of the support composition (Al2O3, SiO2, and USY), the metal oxide loading (0-1 wt %), and the impregnation salt (vanadyl sulfate and ammonium vanadate). These catalysts have been studied by

Analysis of vanadium slags, roasted and leached products. Determination of contents of total vanadium, chromium, sodium, and soluble vanadium

International Nuclear Information System (INIS)

Hasek, Z.

1975-01-01

Accurate, rapid and simple methods were elaborated of determining total vanadium, chromium, and sodium in vanadium slags, and in roasted and leached products in one sample batch. The analysis was conducted in a teflon vial using inorganic acids. A method od determining soluble vanadium in similar materials was also elaborated and verified. (B.S.)

Vanadium alloys for the radiative divertor program of DIII-D

International Nuclear Information System (INIS)

Smith, J.P.; Johnson, W.R.; Stambaugh, R.D.; Trester, P.W.; Smith, D.; Bloom, E.

1995-10-01

Vanadium alloys provide an attractive solution for fusion power plants as they exhibit a potential for low environmental impact due to low level of activation from neutron fluence and a relatively short half-life. They also have attractive material properties for use in a reactor. General Atomics along with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL), has developed a plan to utilize vanadium alloys as part of the Radiative Divertor Project (RDP) modification for the DIII-D tokamak. The goal for using vanadium alloys is to provide a meaningful step towards developing advanced materials for fusion power applications by demonstrating the in-service behavior of a vanadium alloy (V-4Cr-4Ti) in a tokamak in conjunction with developing essential fabrication technology for the manufacture of full-scale vanadium alloy components. A phased approach towards utilizing vanadium in DIII-D is being used starting with small coupons and samples, advancing to a small component, and finally a portion of the new double-null, slotted divertor will be fabricated from vanadium alloy product forms. A major portion of the program is research and development to support fabrication and resolve key issues related to environmental effects

Thermodynamics of oxygen in solid solution in vanadium and niobium--vanadium alloys

International Nuclear Information System (INIS)

Steckel, G.L.

1977-01-01

A thermodynamic study was made of the vanadium-oxygen and niobium-vanadium-oxygen systems utilizing the solid state galvanic cell technique. Investigations were made with a ThO 2 /Y 2 O 3 electrolyte over the temperature ranges 700 to 1200 0 C (973 to 1473 K) for the binary system and 650 to 1150 0 C (923 to 1423 K) for the ternary system. The activity of oxygen in vanadium obeys Henry's law for the temperatures of this investigation for concentrations up to 3.2 at. percent oxygen. For higher concentrations the activity coefficient shows positive deviations from Henry's law. The terminal solubility of oxygen in vanadium was determined. The activity of oxygen in Nb--V alloys obeys Henry's law for the temperatures of this study for oxygen concentrations less than approximately 2 at. percent. For certain Nb/V ratios Henry's law is obeyed for concentrations as high as 6.5 at. percent oxygen. First order entropy and enthalpy interaction coefficients have been determined to describe the effect on the oxygen activity of niobium additions to vanadium-rich alloys with dilute oxygen concentrations. Niobium causes relatively small decreases in the oxygen activity of V-rich alloys and increases the oxygen solubility limit. Vanadium additions to Nb-rich alloys also increases the oxygen solubility and causes substantial decreases in the dilute solution oxygen activities. The change in the thermodynamic properties when molecular oxygen dissolves in vanadium and niobium--vanadium alloys and the equilibrium oxygen pressure over the binary and ternary systems were also determined

An extraction process to recover vanadium from low-grade vanadium-bearing titanomagnetite

Energy Technology Data Exchange (ETDEWEB)

Chen, Desheng; Zhao, Hongxin; Hu, Guoping [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Qi, Tao, E-mail: tqgreen@ipe.ac.cn [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yu, Hongdong; Zhang, Guozhi [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Wang, Lina, E-mail: linawang@ipe.ac.cn [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Wang, Weijing [National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Beijing 100190 (China); Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

2015-08-30

Highlights: • The leaching solution contains high concentration of acid, iron, impurities and lower vanadium. • 99.4% of vanadium and 4.2% of iron were extracted by three-stage extraction process. • 99.6% of vanadium and 5.4% of iron were stripped by three-stage stripping process. • The stripping solution contains 40.16 g/L V{sub 2}O{sub 5}, 0.691 g/L Fe, 0.007 g/L TiO{sub 2} and 0.247 g/L CaO. • The vanadium product of V{sub 2}O{sub 5} with purity of 99.12%, 0.026% Fe and well crystallized. - Abstract: An extraction process to recover vanadium from low-grade vanadium-bearing titanomagnetite was developed. In this study, a mixed solvent system of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) diluted with kerosene was used for the selective extraction of vanadium from a hydrochloric acid leaching solution that contained low vanadium concentration with high concentrations of iron and impurities of Ca, Mg, and Al. In the extraction process, the initial solution pH and the phase ratio had considerable functions in the extraction of vanadium from the hydrochloric acid leaching solution. Under optimal extraction conditions (i.e., 30–40 °C for 10 min, 1:3 phase ratio (O/A), 20% D2EHPA concentration (v/v), and 0–0.8 initial solution pH), 99.4% vanadium and only 4.2% iron were extracted by the three-stage counter-current extraction process. In the stripping process with H{sub 2}SO{sub 4} as the stripping agent and under optimal stripping conditions (i.e., 20% H{sub 2}SO{sub 4} concentration, 5:1 phase ratio (O/A), 20 min stripping time, and 40 °C stripping temperature), 99.6% vanadium and only 5.4% iron were stripped by the three-stage counter-current stripping process. The stripping solution contained 40.16 g/L V{sub 2}O{sub 5}, 0.691g/L Fe, 0.007 g/L TiO{sub 2}, 0.006 g/L SiO{sub 2} and 0.247 g/L CaO. A V{sub 2}O{sub 5} product with a purity of 99.12% V{sub 2}O{sub 5} and only 0.026% Fe was obtained after the oxidation, precipitation

Vanadium in South Africa

International Nuclear Information System (INIS)

Rohrman, B.

1985-01-01

This paper deals briefly with the history of vanadium and its uses, price movement, and world resources. It then describes the titanomagnetite ore of the Bushveld Complex, and the production of vanadium from this ore at Highveld Steel and Vanadium Corporation Limited, giving details of the various processes used, including the roast-leach, rotary-kiln, electric-smelting, shaking-ladle, and basic-oxygen-furnace operations. The paper concludes with a very brief account of the treatment of Highveld slags in Europe for the production of vanadium pentoxide and ferrovanadium

Characterization of vanadium flow battery

Energy Technology Data Exchange (ETDEWEB)

Bindner, H.; Ekman, C.; Gehrke, O.; Isleifsson, F.

2010-10-15

This report summarizes the work done at Risoe DTU testing a vanadium flow battery as part of the project 'Characterisation of Vanadium Batteries' (ForskEl project 6555) with the partners PA Energy A/S and OI Electric A/S under the Danish PSO energy research program. A 15kW/120kWh vanadium battery has been installed as part of the distributed energy systems experimental facility, SYSLAB, at Risoe DTU. A test programme has been carried out to get hands-on experience with the technology, to characterize the battery from a power system point of view and to assess it with respect to integration of wind energy in the Danish power system. The battery has been in operation for 18 months. During time of operation the battery has not shown signs of degradation of performance. It has a round-trip efficiency at full load of approximately 60% (depending on temperature and SOC). The sources of the losses are power conversion in cell stacks/electrolyte, power converter, and auxiliary power consumption from pumps and controller. The response time for the battery is limited at 20kW/s by the ramp rate of the power converter. The battery can thus provide power and frequency support for the power system. Vanadium battery is a potential technology for storage based services to the power system provided investment and O and M cost are low enough and long term operation is documented. (Author)

Optimal Location of Vanadium in Muscovite and Its Geometrical and Electronic Properties by DFT Calculation

Directory of Open Access Journals (Sweden)

Qiushi Zheng

2017-02-01

Full Text Available Vanadium-bearing muscovite is the most valuable component of stone coal, which is a unique source of vanadium manufacture in China. Numbers of experimental studies have been carried out to destroy the carrier muscovite’s structure for efficient extraction of vanadium. Hence, the vanadium location is necessary for exploring the essence of vanadium extraction. Although most infer that vanadium may substitute for trivalent aluminium (Al as the isomorphism in muscovite for the similar atomic radius, there is not enough experimental evidence and theoretical supports to accurately locate the vanadium site in muscovite. In this study, the muscovite model and optimal location of vanadium were calculated by density functional theory (DFT. We find that the vanadium prefers to substitute for the hexa-coordinated aluminum of muscovite for less deformation and lower substitution energy. Furthermore, the local geometry and relative electronic properties were calculated in detail. The basal theoretical research of muscovite contained with vanadium are reported for the first time. It will make a further influence on the technology development of vanadium extraction from stone coal.

Methanesulfonic acid solution as supporting electrolyte for zinc-vanadium redox battery

International Nuclear Information System (INIS)

Tang Chao; Zhou Debi

2012-01-01

Highlights: ► Methanesulfonic acid as supporting electrolyte for V(V)/V(IV) was discussed. ► V(V)/V(IV) concentration as high as 3 mol L −1 was obtained. ► A Zn-V battery was assembled. ► The assembled Zn-V battery has good cycle performance and high cell voltage. - Abstract: The present work was performed in order to evaluate methanesulfonic acid (MSA) as electrolyte medium for V(IV)/V(V) redox couple as positive species applied in redox flow battery (RFB). V-MSA solutions containing more than 3.0 mol L −1 vanadium ions were obtained. Conductivity and viscosity of 3.0 mol L −1 V(IV)/V(V) electrolyte were determined to be 0.10 cm s −1 and 12.37 mPa s respectively. Cyclic voltammetry was conducted to investigate the electrochemical behavior of V(IV)/V(V) redox couple. The diffusion coefficients of V(IV) on Pt electrode in 1.0, 2.0 and 3.0 mol L −1 V(IV)/V(V) electrolytes determined were 3.606 × 10 −6 , 1.813 × 10 −6 and 0.5244 × 10 −6 cm 2 s −1 , respectively. A Zn-V battery was assembled with V(IV)/V(V)-MSA positive species and Zn/Zn(II)-MSA negative species. The cell voltage in charged state was 1.9–2.0 V and discharge voltage reached up to 1.7 V. The average coulombic efficiency and energy efficiency of the assembled cell were 95.85% and 63.90% respectively and it showed a good cyclic charge–discharge performance, which indicates that MSA has a promise application prospect in vanadium redox battery.

Hydration effects on the molecular structure of silica-supported vanadium oxide catalysts: A combined IR, Raman, UV–vis and EXAFS study

NARCIS (Netherlands)

Keller, D.E.; Visser, T.; Soulimani, F.; Koningsberger, D.C.; Weckhuysen, B.M.

2007-01-01

The effect of hydration on the molecular structure of silica-supported vanadium oxide catalysts with loadings of 1–16 wt.% V has been systematically investigated by infrared, Raman, UV–vis and EXAFS spectroscopy. IR and Raman spectra recorded during hydration revealed the formation of V–OH groups,

Neurobehavioral and cytotoxic effects of vanadium during oligodendrocyte maturation: a protective role for erythropoietin.

Science.gov (United States)

Mustapha, Oluwaseun; Oke, Bankole; Offen, Nils; Sirén, Anna-Leena; Olopade, James

2014-07-01

Vanadium exposure has been known to lead to lipid peroxidation, demyelination and oligodendrocytes depletion. We investigated behaviour and glial reactions in juvenile mice after early neonatal exposure to vanadium, and examined the direct effects of vanadium in oligodendrocyte progenitor cultures from embryonic mice. Neonatal pups exposed to vanadium via lactation for 15 and 22 days all had lower body weights. Behavioural tests showed in most instances a reduction in locomotor activity and negative geotaxis. Brain analyses revealed astrocytic activation and demyelination in the vanadium exposed groups compared to the controls. In cell culture, exposure of oligodendrocytes to 300 μM sodium metavanadate significantly increased cell death. Expression of the oligodendrocyte specific proteins, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and oligodendrocyte specific protein (OSP/Claudin) were reduced upon vanadium treatment while simultaneous administration of erythropoietin (EPO; 4-12 U/ml) counteracted vanadium-toxicity. The data suggest that oligodendrocyte damage may explain the increased vulnerability of the juvenile brain to vanadium and support a potential for erythropoietin as a protective agent against vanadium-toxicity during perinatal brain development and maturation. Copyright © 2014 Elsevier B.V. All rights reserved.

Melting technique for vanadium containing steels

Energy Technology Data Exchange (ETDEWEB)

Grishanov, M P; Gutovskij, I B; Vakhrushev, A S

1980-04-28

To descrease cost price of high-quality vanadium steels a method of their melting in open-hearth furnaces with acid lining using slag-metal fraction of vanadium, which is loaded in the content of 2.1-4.7% of melting mass, is suggested. Introduction of slag-metal fraction of vanadium ensures the formation of slag with composition that guarantees the necessary content of vanadium in steel and does not require introduction of expensive vanadium-containing ferroalloys into the melt.

VANADIUM ALLOYS

Science.gov (United States)

Smith, K.F.; Van Thyne, R.J.

1959-05-12

This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

Sol-gel growth of vanadium dioxide

International Nuclear Information System (INIS)

Speck, K.R.

1990-01-01

This thesis examines the chemical reactivity of vanadium (IV) tetrakis(t-butoxide) as a precursor for the sol-gel synthesis of vanadium dioxide. Hydrolysis and condensation of the alkoxide was studied by FTIR spectroscopy. Chemical modification of the vanadium tetraalkoxide by alcohol interchange was studied using 51 V NMR and FTIR. Vanadium dioxide thin films and powders were made from vanadium tetrakis(t-butoxide) by standard sol-gel techniques. Post-deposition heating under nitrogen was necessary to transform amorphous gels into vanadium dioxide. Crystallization of films and powders was studied by FTIR, DSC, TGA, and XRD. Gel-derived vanadium dioxide films undergo a reversible semiconductor-to-metal phase transition near 68C, exhibiting characteristic resistive and spectral changes. The electrical resistance decreased by two to three orders of magnitude and the infrared transmission sharply dropped as the material was cycled through this thermally induced phase transition. The sol-gel method was also used to make doped vanadium dioxide films. Films were doped with tungsten and molybdenum ions to effectively lower the temperature at which the transition occurs

A method for recovery of iron, titanium, and vanadium from vanadium-bearing titanomagnetite

Science.gov (United States)

Zhang, Yi-min; Wang, Li-na; Chen, De-sheng; Wang, Wei-jing; Liu, Ya-hui; Zhao, Hong-xin; Qi, Tao

2018-02-01

An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures: low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.

Extraction-complexonometric determination of vanadium(4) in the presence of vanadium(3)

International Nuclear Information System (INIS)

Gordeeva, M.N.; Ryndina, A.M.; Stanevich, T.V.

1976-01-01

The extraction-complexonometric method has been investigated for determining vanadium(4) in the presence of vanadium (3) with high contents of these forms in the solution analyzed. The method of separation of V(4) and V(3) is based on extraction of the ion acetate of vanadium(4) with eriochrome red B(ERCB) and diphenyl quanidinium (DPG) by a mixture of chloroform and isoamyl alcohol (3:1). To control the content of V(4) and V(3) the method of reciprocal complexonometric titration is used (the titrating solution was a solution of thorium nitride, and xylenol orange was a solution of thorium nitride, and xylenol orange was used as metal indicator). Titration has been carried out in an acid solution at pH=2.8. The developed method has been applied to analysis of lithium-zinc spinels containing both forms of vanadium

Utilization of vanadium alloys in the DIII-D Radiative Divertor Program

International Nuclear Information System (INIS)

Smith, J.P.; Johnson, W.R.; Stambaugh, R.D.; Trester, P.W.; Smith, D.; Bloom, E.

1995-10-01

Vanadium alloys are attractive candidate structural materials for fusion power plants because of their potential for minimum environmental impact due to low neutron activation and rapid activation decay. They also possess favorable material properties for operation in a fusion environment. General Atomics (GA), in conjunction with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory (ORNL), has developed a plan for the utilization of vanadium alloys as part of the Radiative Divertor (RD) upgrade for the DIII-D tokamak. The plan will be carried out in conjunction with General Atomics and the Materials Program of the US Department of Energy (DOE). This application of a vanadium alloy will provide a meaningful step in the development of advanced materials for fusion power devices by: (1) developing necessary materials processing technology for the fabrication of large vanadium alloy components, and (2) demonstrating the in-service behavior of a vanadium alloy (V-4Cr-4Ti) in a tokamak environment. The program consists of three phases: first, small vanadium alloy coupon samples will be exposed in DIII-D at positions in the vessel floor and within the pumping plenum region of the existing divertor structure; second, a small vanadium alloy component will be installed in the existing divertor, and third, during the forthcoming Radiative Divertor modification, scheduled for completion in mid-1997, the upper section of the new double-null, slotted divertor will be fabricated from vanadium alloy product forms. This program also includes research and development (R and D) efforts to support fabrication development and to resolve key issues related to environmental effects

Utilization of vanadium alloys in the DIII-D radiative divertor program

International Nuclear Information System (INIS)

Smith, J.P.; Johnson, W.R.; Stambaugh, R.D.; Trester, P.W.; Smith, D.; Bloom, E.

1996-01-01

Vanadium alloys are attractive candidate structural materials for fusion power plants because of their potential for minimum environmental impact due to low neutron activation and rapid activation decay. They also possess favorable material properties for operation in a fusion environment. General Atomics in conjunction with Argonne National Laboratory and Oak Ridge National Laboratory has developed a plan for the utilization of vanadium alloys as part of the radiative divertor upgrade for the DIII-D tokamak. The plan will be carried out in conjunction with General Atomics and the Materials Program of the US Department of Energy. This application of a vanadium alloy will provide a meaningful step in the development of advanced materials for fusion power devices by: (1) developing necessary materials processing technology for the fabrication of large vanadium alloy components and (2) demonstrating the in-service behavior of a vanadium alloy (V-4Cr-4Ti) in a tokamak environment. The program consists of three phases: first, small vanadium alloy coupon samples will be exposed in DIII-D at positions in the vessel floor and within the pumping plenum region of the existing divertor structure; second, a small vanadium alloy component will be installed in the existing divertor, and third, during the forthcoming radiative divertor modification, scheduled for completion in mid-1997, the upper section of the new double-null, slotted divertor will be fabricated from vanadium alloy product forms. This program also includes research and development efforts to support fabrication development and to resolve key issues related to environmental effects. (orig.)

Dehydrogenation of Ethylbenzene with Carbon Dioxide as Soft Oxidant over Supported Vanadium-Antimony Oxide Catalyst

Energy Technology Data Exchange (ETDEWEB)

Hong, Do Young; Vislovskiy, Vladislav P.; Yoo, Jin S.; Chang, Jong San [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); Park, Sang Eon [Inha University, Incheon (Korea, Republic of); Park, Min Seok [Mongolia International University, Ulaanbaatar (Mongolia)

2005-11-15

This work presents that carbon dioxide, which is a main contributor to the global warming effect, could be utilized as a selective oxidant in the oxidative dehydrogenation of ethylbenzene. The dehydrogenation of ethylbenzene over alumina-supported vanadium-antimony oxide catalyst has been studied under different atmospheres such as inert nitrogen, steam, oxygen or carbon dioxide as diluent or oxidant. Among them, the addition of carbon dioxide gave the highest styrene yield (up to 82%) and styrene selectivity (up to 97%) along with stable activity. Carbon dioxide could play a beneficial role of a selective oxidant in the improvement of the catalytic behavior through the oxidative pathway.

Extraction of Vanadium from Vanadium Slag Via Non-salt Roasting and Ammonium Oxalate Leaching

Science.gov (United States)

Li, Meng; Du, Hao; Zheng, Shili; Wang, Shaona; Zhang, Yang; Liu, Biao; Dreisinger, David Bruce; Zhang, Yi

2017-10-01

A clean method featuring non-salt roasting followed by (NH4)2C2O4 leaching to recover vanadium from vanadium slag was proposed. The carcinogenic Cr6+ compounds and exhaust gases were avoided, and the water generated from vanadate precipitation may be recycled and reused in this new leaching process. The leaching residues may be easily used by a blast furnace. Moreover, (NH4)2C2O4 solution was used as a leaching medium to avoid expensive and complicated ammonium controlling operations as a result of the stability of (NH4)2C2O4 at a high temperature. The transformation mechanisms of vanadium- and chromium-bearing phases were systematically investigated by x-ray diffraction analysis and scanning electron microscopy with energy-disperse x-ray spectrometry, respectively. In addition, the effects of oxygen concentration, roasting temperature, and holding time on vanadium recovery were investigated. Finally, the effects of leaching variables on the vanadium leaching rate were also examined.

Effects of dietary vanadium in mallard ducks

Science.gov (United States)

White, D.H.; Dieter, M.P.

1978-01-01

Adult mallard ducks fed 0, 1, 10, or 100 ppm vanadyl sulfate in the diet were sacrificed after 12 wk on treatment; tissues were analyzed for vanadium. No birds died during the study and body weights did not change. Vanadium accumulated to higher concentrations in the bone and liver than in other tissues. Concentrations in bones of hens were five times those in bones of drakes, suggesting an interaction between vanadium and calcium mobilization in laying hens. Vanadium concentrations in most tissues were significantly correlated and increased with treatment level. Lipid metabolism was altered in laying hens fed 100 ppm vanadium. Very little vanadium accumulated in the eggs of laying hens.

Efficient Separation and Extraction of Vanadium and Chromium in High Chromium Vanadium Slag by Selective Two-Stage Roasting-Leaching

Science.gov (United States)

Wen, Jing; Jiang, Tao; Xu, Yingzhe; Liu, Jiayi; Xue, Xiangxin

2018-04-01

Vanadium and chromium are important rare metals, leading to a focus on high chromium vanadium slag (HCVS) as a potential raw material to extract vanadium and chromium in China. In this work, a novel method based on selective two-stage roasting-leaching was proposed to separate and extract vanadium and chromium efficiently in HCVS. XRD, FT-IR, and SEM were utilized to analyze the phase evolutions and microstructure during the whole process. Calcification roasting, which can calcify vanadium selectively using thermodynamics, was carried out in the first roasting stage to transfer vanadium into acid-soluble vanadate and leave chromium in the leaching residue as (Fe0.6Cr0.4)2O3 after H2SO4 leaching. When HCVS and CaO were mixed in the molar ratio CaO/V2O3 (n(CaO)/n(V2O3)) of 0.5 to 1.25, around 90 pct vanadium and less than 1 pct chromium were extracted in the first leaching liquid, thus achieving the separation of vanadium and chromium. In the second roasting stage, sodium salt, which combines with chromium easily, was added to the first leaching residue to extract chromium and 95.16 pct chromium was extracted under the optimal conditions. The total vanadium and chromium leaching rates were above 95 pct, achieving the efficient separation and extraction of vanadium and chromium. The established method provides a new technique to separate vanadium and chromium during roasting rather than in the liquid form, which is useful for the comprehensive application of HCVS.

Efficient Separation and Extraction of Vanadium and Chromium in High Chromium Vanadium Slag by Selective Two-Stage Roasting-Leaching

Science.gov (United States)

Wen, Jing; Jiang, Tao; Xu, Yingzhe; Liu, Jiayi; Xue, Xiangxin

2018-06-01

Vanadium and chromium are important rare metals, leading to a focus on high chromium vanadium slag (HCVS) as a potential raw material to extract vanadium and chromium in China. In this work, a novel method based on selective two-stage roasting-leaching was proposed to separate and extract vanadium and chromium efficiently in HCVS. XRD, FT-IR, and SEM were utilized to analyze the phase evolutions and microstructure during the whole process. Calcification roasting, which can calcify vanadium selectively using thermodynamics, was carried out in the first roasting stage to transfer vanadium into acid-soluble vanadate and leave chromium in the leaching residue as (Fe0.6Cr0.4)2O3 after H2SO4 leaching. When HCVS and CaO were mixed in the molar ratio CaO/V2O3 (n(CaO)/n(V2O3)) of 0.5 to 1.25, around 90 pct vanadium and less than 1 pct chromium were extracted in the first leaching liquid, thus achieving the separation of vanadium and chromium. In the second roasting stage, sodium salt, which combines with chromium easily, was added to the first leaching residue to extract chromium and 95.16 pct chromium was extracted under the optimal conditions. The total vanadium and chromium leaching rates were above 95 pct, achieving the efficient separation and extraction of vanadium and chromium. The established method provides a new technique to separate vanadium and chromium during roasting rather than in the liquid form, which is useful for the comprehensive application of HCVS.

Vanadium recycling in the United States in 2004

Science.gov (United States)

Goonan, Thomas G.

2011-01-01

As one of a series of reports that describe the recycling of metal commodities in the United States, this report discusses the flow of vanadium in the U.S. economy in 2004. This report includes a description of vanadium supply and demand in the United States and illustrates the extent of vanadium recycling and recycling trends. In 2004, apparent vanadium consumption, by end use, in the United States was 3,820 metric tons (t) in steelmaking and 232 t in manufacturing, of which 17 t was for the production of superalloys and 215 t was for the production of other alloys, cast iron, catalysts, and chemicals. Vanadium use in steel is almost entirely dissipative because recovery of vanadium from steel scrap is chemically impeded under the oxidizing conditions in steelmaking furnaces. The greatest amount of vanadium recycling is in the superalloy, other-alloy, and catalyst sectors of the vanadium market. Vanadium-bearing catalysts are associated with hydrocarbon recovery and refining in the oil industry. In 2004, 2,850 t of vanadium contained in alloy scrap and spent catalysts was recycled, which amounted to about 44 percent of U.S. domestic production. About 94 percent of vanadium use in the United States was dissipative (3,820 t in steel/4,050 t in steel+fabricated products).

Comparison of Ultrasound-Assisted and Regular Leaching of Vanadium and Chromium from Roasted High Chromium Vanadium Slag

Science.gov (United States)

Wen, Jing; Jiang, Tao; Gao, Huiyang; Liu, Yajing; Zheng, Xiaole; Xue, Xiangxin

2018-02-01

Ultrasound-assisted leaching (UAL) was used for vanadium and chromium leaching from roasted material obtained by the calcification roasting of high-chromium-vanadium slag. UAL was compared with regular leaching. The effect of the leaching time and temperature, acid concentration, and liquid-solid ratio on the vanadium and chromium leaching behaviors was investigated. The UAL mechanism was determined from particle-size-distribution and microstructure analyses. UAL decreased the reaction time and leaching temperature significantly. Furthermore, 96.67% vanadium and less than 1% chromium were leached at 60°C for 60 min with 20% H2SO4 at a liquid-solid ratio of 8, which was higher than the maximum vanadium leaching rate of 90.89% obtained using regular leaching at 80°C for 120 min. Ultrasonic waves broke and dispersed the solid sample because of ultrasonic cavitation, which increased the contact area of the roasted sample and the leaching medium, the solid-liquid mass transfer, and the vanadium leaching rate.

Fabrication of vanadium cans for neutron diffraction experiments

Energy Technology Data Exchange (ETDEWEB)

Chung, Chin man; Baik, Sung Hoon; Park, Sun Kyu

1999-12-01

The laser weld technique of vanadium developed to experiment for neutron diffraction of HANARO. The demands for this laser welding technique were applied to process control in vanadium film welding and to fabricate various sizing vanadium cans. The vanadium can had a advantage to have less coherent in neutron. KAERI developed the fabrication jig of 6-12 mm diameter cans using 0.125 mm vanadium thin film, and investigated the laser welding procedure for making the various diameter and length of vanadium cans using the fabricated jigs and Nd:YAG laser. (author)

Bioleaching of vanadium from barren stone coal and its effect on the transition of vanadium speciation and mineral phase

Science.gov (United States)

Wang, Xin; Lin, Hai; Dong, Ying-bo; Li, Gan-yu

2018-03-01

This study determined the optimal conditions required to obtain maximum vanadium extraction and examined the transition of mineral phases and vanadium speciation during the bioleaching process. Parameters including the initial pH value, initial Fe2+ concentration, solid load, and inoculum quantity were examined. The results revealed that 48.92wt% of the vanadium was extracted through bioleaching under optimal conditions. Comparatively, the chemical leaching yield (H2SO4, pH 2.0) showed a slower and milder increase in vanadium yield. The vanadium bioleaching yield was 35.11wt% greater than the chemical leaching yield. The Community Bureau of Reference (BCR) sequential extraction results revealed that 88.62wt% of vanadium existed in the residual fraction. The bacteria substantially changed the distribution of the vanadium speciation during the leaching process, and the residual fraction decreased to 48.44wt%. The X-ray diffraction (XRD) and Fourier transform infrared (FTIR) results provided evidence that the crystal lattice structure of muscovite was destroyed by the bacteria.

Recovery of vanadium oxide

International Nuclear Information System (INIS)

Bates, C.P.; Clark, N.E.

1985-01-01

This invention relates to the recovery of vanadium oxide from molten metal. The invention provides a method for recovering vanadium oxide from molten metal, which includes passing oxygen and at least one coolant gas or shroud into the molten metal by way of at least one elongate lance. The invention also provides an arrangement for the recovery of vanadium oxide from molten metal, which includes at least one elongate lance extending into the molten metal. The lance is provided with at least one elongate bore extending therethrough. Means are provided to allow at least oxygen and at least one coolant gas to pass through the lance and into the molten metal

Determination of vanadium

International Nuclear Information System (INIS)

Stepin, V.V.; Kurbatova, V.I.; Fedorova, N.D.

1980-01-01

Titrimetric and potentiometric methods of vanadium determination in ferrovanadium are developed. The essence of the titrimetric method using phenylanthranilic acid as indicator is in the following. Ferrovanadium weighed amount is dissolved in H 2 SO 4 , vanadium is oxidated by potassium permanganate to V(5) and is titrated by a solution of double salt of sulfuric Fe(2) and ammonium in the presence of indicator. Potentiometric titration is carried out using the same indicator [ru

Slag recycling of irradiated vanadium

International Nuclear Information System (INIS)

Gorman, P.K.

1995-01-01

An experimental inductoslag apparatus to recycle irradiated vanadium was fabricated and tested. An experimental electroslag apparatus was also used to test possible slags. The testing was carried out with slag materials that were fabricated along with impurity bearing vanadium samples. Results obtained include computer simulated thermochemical calculations and experimentally determined removal efficiencies of the transmutation impurities. Analyses of the samples before and after testing were carried out to determine if the slag did indeed remove the transmutation impurities from the irradiated vanadium

Methods for making lithium vanadium oxide electrode materials

Science.gov (United States)

Schutts, Scott M.; Kinney, Robert J.

2000-01-01

A method of making vanadium oxide formulations is presented. In one method of preparing lithium vanadium oxide for use as an electrode material, the method involves: admixing a particulate form of a lithium compound and a particulate form of a vanadium compound; jet milling the particulate admixture of the lithium and vanadium compounds; and heating the jet milled particulate admixture at a temperature below the melting temperature of the admixture to form lithium vanadium oxide.

Hysteresis Phenomena in Sulfur Dioxide Oxidation over Supported Vanadium Catalysts

DEFF Research Database (Denmark)

Masters, Stephen G.; Eriksen, Kim Michael; Fehrmann, Rasmus

1997-01-01

Catalyst deactivation and hysteresis behavior in industrial SO2-oxidation catalysts have been studied in the temperature region 350-480 C by combined in situ EPR spectroscopy and catalytic activity measurements. The feed gas composition simulated sulfuric acid synthesis gas and wet/dry de......NOx'ed flue gas. The vanadium (IV) compound K4(VO)3(SO4)5 precipitated during all the investigated conditions hence causing catalyst deactivation. Hysteresis behavior of both the catalytic activity and the V(IV) content was observed during reheating....

Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

Science.gov (United States)

Natalio, Filipe; André, Rute; Hartog, Aloysius F.; Stoll, Brigitte; Jochum, Klaus Peter; Wever, Ron; Tremel, Wolfgang

2012-08-01

Marine biofouling--the colonization of small marine microorganisms on surfaces that are directly exposed to seawater, such as ships' hulls--is an expensive problem that is currently without an environmentally compatible solution. Biofouling leads to increased hydrodynamic drag, which, in turn, causes increased fuel consumption and greenhouse gas emissions. Tributyltin-free antifouling coatings and paints based on metal complexes or biocides have been shown to efficiently prevent marine biofouling. However, these materials can damage the environment through metal leaching (for example, of copper and zinc) and bacteria resistance. Here, we show that vanadium pentoxide nanowires act like naturally occurring vanadium haloperoxidases to prevent marine biofouling. In the presence of bromide ions and hydrogen peroxide, the nanowires catalyse the oxidation of bromide ions to hypobromous acid (HOBr). Singlet molecular oxygen (1O2) is formed and this exerts strong antibacterial activity, which prevents marine biofouling without being toxic to marine biota. Vanadium pentoxide nanowires have the potential to be an alternative approach to conventional anti-biofouling agents.

Vanadium recycling for fusion reactors

International Nuclear Information System (INIS)

Dolan, T.J.; Butterworth, G.J.

1994-04-01

Very stringent purity specifications must be applied to low activation vanadium alloys, in order to meet recycling goals requiring low residual dose rates after 50--100 years. Methods of vanadium production and purification which might meet these limits are described. Following a suitable cooling period after their use, the vanadium alloy components can be melted in a controlled atmosphere to remove volatile radioisotopes. The aim of the melting and decontamination process will be the achievement of dose rates low enough for ''hands-on'' refabrication of new reactor components from the reclaimed metal. The processes required to permit hands-on recycling appear to be technically feasible, and demonstration experiments are recommended. Background information relevant to the use of vanadium alloys in fusion reactors, including health hazards, resources, and economics, is provided

Transient-response study of CO insertion into CHx surface intermediates on a vanadium-promoted rhodium catalyst

NARCIS (Netherlands)

Koerts, T.; Santen, van R.A.

1992-01-01

The rate of CO insertion into surface CHx species was investigated on silica-supported rhodium and rhodium-vanadium catalysts. Isotopically labelled 13CO was used in a transient kinetic experiment under steady-state conditions. A main conclusion is that vanadium promotion does not affect the rate of

Vanadium Transitions in the Spectrum of Arcturus

Science.gov (United States)

Wood, M. P.; Sneden, C.; Lawler, J. E.; Den Hartog, E. A.; Cowan, J. J.; Nave, G.

2018-02-01

We derive a new abundance for vanadium in the bright, mildly metal-poor red giant Arcturus. This star has an excellent high-resolution spectral atlas and well-understood atmospheric parameters, and it displays a rich set of neutral vanadium lines that are available for abundance extraction. We employ a newly recorded set of laboratory FTS spectra to investigate any potential discrepancies in previously reported V I log(gf) values near 900 nm. These new spectra support our earlier laboratory transition data and the calibration method utilized in that study. We then perform a synthetic spectrum analysis of weak V I features in Arcturus, deriving log ε(V) = 3.54 ± 0.01 (σ = 0.04) from 55 lines. There are no significant abundance trends with wavelength, line strength, or lower excitation energy.

Vacancy distribution in nonstoichiometric vanadium monoxide

International Nuclear Information System (INIS)

Gusev, A.I.; Davydov, D.A.; Valeeva, A.A.

2011-01-01

Graphical abstract: Display Omitted Research highlights: → A certain fraction of vanadium atoms in disordered cubic vanadium monoxide VO y and ordered tetragonal phase V 52 O 64 is located in tetrahedral positions of a basic cubic lattice. → These positions are never occupied by any atoms in other strongly nonstoichiometric carbides, nitrides and oxides. → Both disordered and ordered structures of vanadium monoxide are characterized by the presence of short-range order of displacements in the oxygen sublattice and short-range order of substitution in the metal sublattice. → The short-range order of displacement is caused by the local displacements of O atoms from V (t) atoms occupying tetrahedral positions. The short-range order of substitution appears because V (t) atoms in the tetrahedral positions are always in the environment of four vacancies □ of the vanadium sublattice. - Abstract: Structural vacancy distribution in the crystal lattice of the tetragonal V 52 O 64 superstructure which is formed on the basis of disordered superstoichiometric cubic vanadium monoxide VO y ≡V x O z is experimentally determined and the presence of significant local atomic displacements and large local microstrains in a crystal lattice of real ordered phase is established. It is shown that the relaxation of local microstrains takes place owing to the basic disordered cubic phase grain refinement and a formation of ordered phase domains. The ordered phase domains grow in the direction from the boundaries to the centre of grains of the disordered basic cubic phase. Isothermal evolution at 970 K of the average domain size in ordered VO 1.29 vanadium monoxide is established. It is shown that the short-range order presents in a metal sublattice of disordered cubic VO y vanadium monoxide. The character of the short-range order is such that vanadium atoms occupying tetrahedral positions are in the environment of four vacant sites of the vanadium sublattice. This means that the

Possible Cardiotoxic Effects of Vanadium

Directory of Open Access Journals (Sweden)

Parveen Parkash

1990-12-01

Full Text Available Vanadium, a ubiquitous element, is physiologically and pharmacologically an active substance and is present in most of mammalian tissues Jandhala and Horn, 1983. Large corpus of information exists on the mode of action of vanadium on cardiac muscles (Jandhala and Horn, 1983., Solaro et al, 1980, but the basis of pharma­cological lesion underlying its cardiac toxi­city is still poorly understood. Except for the solitary report of Lewis (1958 to best of our knowledge no information exists on the effect of vanadium on the functioning of heart as shown by electrocardiography.Large amounts of vanadium are relea­sed into atmosphere by combustion of fossil fuel (Vouk, 1979 and due to rapid indus­trialisation its environmental concentra­tion is reported to be increasing (Goldberg et al, 1974., Jaffe and Walters, 1977., Vouk, 1979. This necessitates the monitoring of its environmental and occupational hazards. In the present study cardiac side effects of vanadium, as revealed through ECG has been investigated in rabbits, since the electrocardiogram of rabbit resembles with of man in essential details (Weisborth et al, 1974.

Thermophysical data of liquid vanadium

International Nuclear Information System (INIS)

Pottlacher, G.; Huepf, T.; Wilthan, B.; Cagran, C.

2007-01-01

Although vanadium is commonly used as an additive in the steel production, literature data for thermophysical properties of vanadium around the melting point are sparse and show, where available a variation over a wide range. This manifests especially in the melting temperature (variation of ±30 K), heat of fusion, or specific enthalpy. This recent work presents the results of thermophysical measurements on vanadium including normal spectral emissivity at 684.5 nm. The aim was to obtain another full dataset of properties (enthalpy, heat of fusion, electrical resistivity, thermal conductivity, emissivity) of liquid vanadium to either confirm existing recommendations for certain properties or presenting newer measurements for comparison leading towards such recommendations. Summarizing, the following results for thermophysical properties at the melting point have been obtained: radiance temperature at melting (650 nm) T r,m = 1993 K, melting temperature T m = 2199 K, normal spectral emissivity at melting (684.5 nm) ε = 0.353. An observed feature of all measured data and results is, that a much better agreement with literature references exists for the liquid phase than in the solid state, thus we have restricted the presentation to liquid vanadium

Characterization of vanadium flow battery. Revised

Energy Technology Data Exchange (ETDEWEB)

Bindner, H.; Ekman, C.; Gehrke, O.; Isleifsson, F.

2011-02-15

This report summarizes the work done at Risoe-DTU testing a vanadium flow battery as part of the project ''Characterisation of Vanadium Batteries'' (ForskEl project 6555) with the partners PA Energy A/S and OI Electric A/S under the Danish PSO energy research program. A 15kW/120kWh vanadium battery has been installed as part of the distributed energy systems experimental facility, SYSLAB, at Risoe DTU. A test programme has been carried out to get hands-on experience with the technology, to characterize the battery from a power system point of view and to assess it with respect to integration of wind energy in the Danish power system. The battery has been in operation for 18 months. During time of operation the battery has not shown signs of degradation of performance. It has a round-trip efficiency at full load of approximately 60% (depending on temperature and SOC). The sources of the losses are power conversion in cell stacks/electrolyte, power converter, and auxiliary power consumption from pumps and controller. The efficiency was not influenced by the cycling of the battery. The response time for the battery is limited at 20kW/s by the ramp rate of the power converter. The battery can thus provide power and frequency support for the power system. The battery was operated together with a 11kW stall-regulated Gaia wind turbine to smooth the output of the wind turbine and during the tests the battery proved capable of firming the output of the wind turbine. Vanadium battery is a potential technology for storage based services to the power system provided investment and O and M cost are low enough and long term operation is documented. (Author)

Vanadium alloys for structural applications in fusion systems: A review of vanadium alloy mechanical and physical properties

Energy Technology Data Exchange (ETDEWEB)

Loomis, B.A.; Smith, D.L.

1991-12-16

The current knowledge is reviewed on (1) the effects of neutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling of vanadium-base alloys, (2) the compatibility of vanadium-base alloys with liquid lithium, water, and helium environments, and (3) the effects of hydrogen and helium on the physical and mechanical properties of vanadium alloys that are potential candidates for structural materials applications in fusion systems. Also, physical and mechanical properties issues are identified that have not been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion devices and/or in fusion reactors.

Vanadium alloys for structural applications in fusion systems: A review of vanadium alloy mechanical and physical properties

International Nuclear Information System (INIS)

Loomis, B.A.; Smith, D.L.

1991-01-01

The current knowledge is reviewed on (1) the effects of neutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling of vanadium-base alloys, (2) the compatibility of vanadium-base alloys with liquid lithium, water, and helium environments, and (3) the effects of hydrogen and helium on the physical and mechanical properties of vanadium alloys that are potential candidates for structural materials applications in fusion systems. Also, physical and mechanical properties issues are identified that have not been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion devices and/or in fusion reactors

Vanadium bioavailability in soils amended with blast furnace slag

Energy Technology Data Exchange (ETDEWEB)

Larsson, Maja A., E-mail: maja.larsson@slu.se [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Baken, Stijn, E-mail: stijn.baken@ees.kuleuven.be [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Smolders, Erik, E-mail: erik.smolders@ees.kuleuven.be [Department of Earth and Environmental Sciences, Leuven University, Kasteelpark Arenberg 20 bus 2459, 3001 Leuven (Belgium); Cubadda, Francesco, E-mail: francesco.cubadda@iss.it [Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161 (Italy); Gustafsson, Jon Petter, E-mail: jon-petter.gustafsson@slu.se [Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, 750 07 Uppsala (Sweden); Division of Land and Water Resources Engineering, KTH Royal Institute of Technology, Brinellvägen 28, 100 44 Stockholm (Sweden)

2015-10-15

Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg{sup −1}) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment.

Determination of Leachable Vanadium (V) in Sediment

African Journals Online (AJOL)

NICO

A method for speciation of vanadium in solid samples was developed for quantification of vanadium(+5) in solid samples of sediment Certified Reference Materials ... element in such environmental samples as soil, sediments and plants.3,4–5 Validation of the ... Sample Preparation for the Determination of. Vanadium(+5).

The role of phosphate additive in stabilization of sulphuric-acid-based vanadium(V) electrolyte for all-vanadium redox-flow batteries

Science.gov (United States)

Roznyatovskaya, Nataliya V.; Roznyatovsky, Vitaly A.; Höhne, Carl-Christoph; Fühl, Matthias; Gerber, Tobias; Küttinger, Michael; Noack, Jens; Fischer, Peter; Pinkwart, Karsten; Tübke, Jens

2017-09-01

Catholyte in all-vanadium redox-flow battery (VRFB) which consists of vanadium salts dissolved in sulphuric acid is known to be stabilized by phosphoric acid to slow down the thermal aging at temperatures higher than 40 °C. To reveal the role of phosphoric acid, the thermally-induced aggregation is investigated using variable-temperature 51V, 31P, 17O, 1H nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS). The results indicate that the thermal stabilization of vanadium(V) electrolyte is attained by the involvement of monomeric and dimeric vanadium(V) species in the reaction with phosphoric acid which is concurrent to the formation of neutral hydroxo-aqua vanadium(V) precipitation precursor. The dimers are stabilized by counter ions due to association reaction or if such stabilization is not possible, precipitation of vanadium pentoxide is favored. The evolution of particles size distributions at 50 °C in electrolyte samples containing 1.6 M vanadium and 4.0 M total sulphate and the pathways of precipitate formation are discussed. The optimal total phosphate concentration is found to be of 0.15 M. However, the induction time is assumed to be dependent not only on the total phosphate concentrations, but also on the ratio of total vanadium(V) to sulphate concentrations.

Evaluation of the nanomechanical properties of vanadium and native oxide vanadium thin films prepared by RF magnetron sputtering

International Nuclear Information System (INIS)

Mamun, M.A.; Zhang, K.; Baumgart, H.; Elmustafa, A.A.

2015-01-01

Graphical abstract: - Highlights: • V films of 50, 75, 100 nm thickness were deposited on Si by RF magnetron sputtering. • We studied structural/mechanical properties by XRD, FE-SEM, AFM, and nanoindentation. • The hardness increased from 9.0 to 14.0 GPa for 100 to 50 nm. • The modulus showed no correlation with thickness or native oxide formation. • Native oxide formation resulted in grain enlargement and roughness reduction. - Abstract: Polycrystalline vanadium thin films of 50, 75, and 100 nm thickness were deposited by magnetron sputtering of a vanadium metal target of 2 inch diameter with 99.9% purity on native oxide covered Si substrates. One set of the fabricated samples were kept in moisture free environment and the other set was exposed to ambient air at room temperature for a long period of time that resulted in formation of native oxide prior to testing. The crystal structure and phase purity of the vanadium and the oxidized vanadium thin films were characterized by X-ray diffraction (XRD). The XRD results yield a preferential (1 1 0), and (2 0 0) orientation of the polycrystalline V films and (0 0 4) vanadium oxide (V 3 O 7 ). The vanadium films thickness were verified using field emission scanning electron microscopy and the films surface morphologies were inspected using atomic force microscopy (AFM). AFM images reveal surface roughness was observed to increase with increasing film thickness and also subsequent to oxidation at room temperature. The nanomechanical properties were measured by nanoindentation to evaluate the modulus and hardness of the vanadium and the oxidized vanadium thin films. The elastic modulus of the vanadium and the oxidized vanadium films was estimated as 150 GPa at 30% film thickness and the elastic modulus of the bulk vanadium target is estimated as 135 GPa. The measured hardness of the vanadium films at 30% film thickness varies between 9 and 14 GPa for the 100 and 50 nm films, respectively, exhibiting size effects

Color and vanadium valency in V-doped ZrO2

International Nuclear Information System (INIS)

Ren, Feng; Ishida, Shingo; Takeuchi, Nobuyuki

1993-01-01

The distribution and chemical states of vanadium in V-doped ZrO 2 were studied to clarify the origin of the color of vanadium-zirconium yellow pigment in comparison with vanadium-tin yellow pigment. ESCA data and measurements of lattice constants of V-doped ZrO 2 revealed that vanadium was dissolved mainly as V 4+ substituting for Zr in ZrO 2 lattice, and its solubility limit was 0.5 wt% as V 2 O 5 . It was found that the yellow color of vanadium-zirconium yellow was produced predominantly by the dissolved vanadium and that the contribution of vanadium oxide on ZrO 2 grains to the yellow color was about 1.30 of that of the dissolved vanadium when compared on the basis of equimolar quantity of vanadium. Most of the undissolved vanadium oxide was in an amorphous or a poorly crystallized state

A new oxidimetric reagent: potassium dichromate in a strong phosphoric acid medium-VI Potentiometric titration of vanadium(III) alone and in mixture with vanadium(IV).

Science.gov (United States)

Rao, G G; Rao, P K

1966-09-01

Vanadium(III) can be titrated at room temperature with potassium dichromate in an 8-12M phosphoric acid medium. Two potential breaks are observed in 12M phosphoric add with 0.2N potassium dichromate, the first corresponding to the oxidation of vanadium(III) to vanadium(IV) and the second to the oxidation of vanadium(IV) to vanadium(V). In titrations with 0.05N dichromate only the first break in potential is clearly observed. The method has been extended to the titration of mixtures of vanadium(III) and vanadium(IV). Conditions have also been found for the visual titration of vanadium(III) using ferroln or barium diphenylamine sulphonate as indicator.

X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Hohn, Keith, L.

2006-01-09

Metal oxide nanocrystals offer significant potential for use as catalysts or catalyst supports due to their high surface areas and unique chemical properties that result from the high number of exposed corners and edges. However, little is known about the catalytic activity of these materials, especially as oxidation catalysts. This research focused on the preparation, characterization and use of vanadium-containing nanocrystals as selective oxidation catalysts. Three vanadium-containing nanocrystals were prepared using a modified sol-gel procedure: V/MgO, V/SiO2, and vanadium phosphate (VPO). These represent active oxidation catalysts for a number of industrially relevant reactions. The catalysts were characterized by x-ray diffraction and Raman, UV-VIS, infrared and x-ray absorption spectroscopies with the goal of determining the primary structural and chemical differences between nanocrystals and microcrystals. The catalytic activity of these catalysts was also studied in oxidative dehydrogenation of butane and methanol oxidation to formaldehyde. V/MgO nanocrystals were investigated for activity in oxidative dehydrogenation of butane and compared to conventional V/MgO catalysts. Characterization of V/MgO catalysts using Raman spectroscopy and x-ray absorption spectroscopy showed that both types of catalysts contained magnesium orthovanadate at vanadium loadings below 15 weight%, but above that loading, magnesium pyrovanadate may have been present. In general, MgO nanocrystals had roughly half the crystal size and double the surface area of the conventional MgO. In oxidative dehydrogenation of butane, nanocrystalline V/MgO gave higher selectivity to butene than conventional V/MgO at the same conversion. This difference was attributed to differences in vanadium domain size resulting from the higher surface areas of the nanocrystalline support, since characterization suggested that similar vanadium phases were present on both types of catalysts. Experiments in

A combined theoretical-experimental study of interactions between vanadium ions and Nafion membrane in all-vanadium redox flow batteries

Science.gov (United States)

Intan, Nadia N.; Klyukin, Konstantin; Zimudzi, Tawanda J.; Hickner, Michael A.; Alexandrov, Vitaly

2018-01-01

Vanadium redox flow batteries (VRFBs) are a promising solution for large-scale energy storage, but a number of problems still impede the deployment of long-lifetime VRFBs. One important aspect of efficient operation of VRFBs is understanding interactions between vanadium species and the membrane. Herein, we investigate the interactions between all four vanadium cations and Nafion membrane by a combination of infrared (IR) spectroscopy and density-functional-theory (DFT)-based static and molecular dynamics simulations. It is observed that vanadium species primarily lead to changes in the IR spectrum of Nafion in the SO3- spectral region which is attributed to the interaction between vanadium species and the SO3- exchange sites. DFT calculations of vanadium -Nafion complexes in the gas phase show that it is thermodynamically favorable for all vanadium cations to bind to SO3- via a contact pair mechanism. Car-Parrinello molecular dynamics-based metadynamics simulations of cation-Nafion systems in aqueous solution suggest that V2+ and V3+ species coordinate spontaneously to SO3-, which is not the case for VO2+ and VO2+ . The interaction behavior of the uncycled membrane determined in this study is used to explain the experimentally observed changes in the vibrational spectra, and is discussed in light of previous results on device-cycled membranes.

Vaporization study on vanadium monoxide and two-phase mixture of vanadium and vanadium monoxide by mass-spectrometric method

International Nuclear Information System (INIS)

Banchorndhevakul, W.; Matsui, Tsuneo; Naito, Keiji

1986-01-01

The vapor pressures over single phase vanadium monoxide VO 1.022 (s) and the two-phase mixture of vanadium metal (β phase) and vanadium monoxide were measured by mass-spectrometric method in the temperature range of 1,803 ∼ 1,990 and 1,703 ∼ 1,884 K, respectively. The main gas species over both systems were found to be VO(g) and V(g). The vapor pressure of VO(g) over the two-phase mixture of V(s) and VO(s) was a little lower than that over single phase VO(s). The vapor pressure of V(g) over the two-phase mixture was nearly equal to that over single phase. From the vapor pressure data, the enthalpies of vaporization, the enthalpies of formation for VO(g) and V(g) and the dissociation energy of VO(g) were determined. The oxygen partial pressure was calculated as a function of temperature from the vapor pressures of VO(g) and V(g), from which the partial molar enthalpies and entropies of oxygen in both systems were obtained. (author)

Effective Recovery of Vanadium from Oil Refinery Waste into Vanadium-Based Metal-Organic Frameworks.

Science.gov (United States)

Zhan, Guowu; Ng, Wei Cheng; Lin, Wenlin Yvonne; Koh, Shin Nuo; Wang, Chi-Hwa

2018-03-06

Carbon black waste, an oil refinery waste, contains a high concentration of vanadium(V) leftover from the processing of crude oil. For the sake of environmental sustainability, it is therefore of interest to recover the vanadium as useful products instead of disposing of it. In this work, V was recovered in the form of vanadium-based metal-organic frameworks (V-MOFs) via a novel pathway by using the leaching solution of carbon black waste instead of commercially available vanadium chemicals. Two different types of V-MOFs with high levels of crystallinity and phase purity were fabricated in very high yields (>98%) based on a coordination modulation method. The V-MOFs exhibited well-defined and controlled shapes such as nanofibers (length: > 10 μm) and nanorods (length: ∼270 nm). Furthermore, the V-MOFs showed high catalytic activities for the oxidation of benzyl alcohol to benzaldehyde, indicating the strong potential of the waste-derived V-MOFs in catalysis applications. Overall, our work offers a green synthesis pathway for the preparation of V-MOFs by using heavy metals of industrial waste as the metal source.

Effect of substrate temperature on thermochromic vanadium dioxide thin films sputtered from vanadium target

Science.gov (United States)

Madiba, I. G.; Kotsedi, L.; Ngom, B. D.; Khanyile, B. S.; Maaza, M.

2018-05-01

Vanadium dioxide films have been known as the most promising thermochromic thin films for smart windows which self-control the solar radiation and heat transfer for energy saving, comfort in houses and automotives. Such an attractive technological application is due to the fact that vanadium dioxide crystals exhibit a fast semiconductor-to-metal phase transition at a transition temperature Tc of about 68 °C, together with sharp optical changes from high transmitive to high reflective coatings in the IR spectral region. The phase transition has been associated with the nature of the microstructure, stoichiometry and stresses related to the oxide. This study reports on the effect of the crystallographic quality controlled by the substrate temperature on the thermochromic properties of vanadium dioxide thin films synthesized by reactive radio frequency inverted cylindrical magnetron sputtering from vanadium target. The reports results are based on X-ray diffraction, Atomic force microscopy, and UV-Visible spectrophotometer. The average crystalline grain size of VO2 increases with the substrate temperature, inducing stress related phenomena within the films.

Peculiarities of powder metallurgy of vanadium and its alloys

International Nuclear Information System (INIS)

Radomysel'skij, I.D.; Solntsev, V.P.; Evtushenko, O.V.

1987-01-01

Literature data on preparation of vanadium powder and powder materials on the vanadium base are generalized. Application of powder metallurgy engineering, allowing simulaneously to introduce practically any strengthening and solid-lubricating components as well as to alloy vanadium, permits undoubtedly to develop composite materials on the vanadium base

Reaction between vanadium trichloride oxide and hydrogen sulfide

International Nuclear Information System (INIS)

Yajima, Akimasa; Matsuzaki, Ryoko; Saeki, Yuzo

1978-01-01

The details of the reaction between vanadium trichloride oxide and hydrogen sulfide were examined at 20 and 60 0 C. The main products by the reaction were vanadium dichloride oxide, sulfur, and hydrogen chloride. In addition to these products, small amounts of vanadium trichloride, vanadium tetrachloride, disulfur dichloride, and sulfur dioxide were formed. The formations of the above-mentioned reaction products can be explained as follows: The first stage is the reaction between vanadium trichloride oxide and hydrogen sulfide, 2VOCl 3 (l) + H 2 S(g)→2VOCl 2 (s) + S(s) + 2HCl(g). Then the resulting sulfur reacts with the unreacted vanadium trichloride oxide, 2VOCl 3 (l) + 2S(s)→2VOCl 2 (s) + S 2 Cl 2 (l). The resulting disulfur dichloride subsequently reacts with the unreacted vanadium trichloride oxide, 2VOCl 3 (l) + S 2 Cl 2 (l)→2VCl 4 (l) + S(s) + SO 2 (g). The resulting vanadium tetrachloride reacts with the sulfur formed during the reaction, 2VCl 4 (l) + 2S(s)→2VCl 3 (s) + S 2 Cl 2 (l), and also reacts with hydrogen sulfide, 2VCl 4 (l) + H 2 S(g)→2VCl 3 (s) + S(s) + 2HCl(g). (auth.)

Roasting and leaching behaviors of vanadium and chromium in calcification roasting-acid leaching of high-chromium vanadium slag

Science.gov (United States)

Wen, Jing; Jiang, Tao; Zhou, Mi; Gao, Hui-yang; Liu, Jia-yi; Xue, Xiang-xin

2018-05-01

Calcification roasting-acid leaching of high-chromium vanadium slag (HCVS) was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium. The effects of the purity of CaO, molar ratio between CaO and V2O5 ( n(CaO)/ n(V2O5)), roasting temperature, holding time, and the heating rate used in the oxidation-calcification processes were investigated. The roasting process and mechanism were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry-differential scanning calorimetry (TG-DSC). The results show that most of vanadium reacted with CaO to generate calcium vanadates and transferred into the leaching liquid, whereas almost all of the chromium remained in the leaching residue in the form of (Fe0.6Cr0.4)2O3. Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with CaO. Moreover, CaO was more likely to combine with vanadium, as further confirmed by thermodynamic analysis. When the HCVS with CaO added in an n(CaO)/ n(V2O5) ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min, the leaching ratios of vanadium and chromium reached 91.14% and 0.49%, respectively; thus, efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium. Furthermore, the oxidation and calcification reactions of the spinel phases occurred at 592 and 630°C for n(CaO)/ n(V2O5) ratios of 0.5 and 5, respectively.

Local structure of vanadium in doped LiFePO4

International Nuclear Information System (INIS)

Zhao, Ting; Xu, Wei; Ye, Qing; Cheng, Jie; Zhao, Haifeng; Chu, Wangsheng; Wu, Ziyu; Univ. of Science and Technology of China, Hefei; Xia, Dingguo

2010-01-01

LiFePO 4 composites with 5 at.% vanadium doping are prepared by solid state reactions. X-ray absorption fine-structure spectroscopy is used as a novel technique to identify vanadium sites. Both experimental analyses and theoretical simulations show that vanadium does not enter into the LiFePO 4 crystal lattice. When the vanadium concentration is lower then 1 at.%, the dopant remains insoluble. Thus, a single-phase vanadium-doped LiFePO4 cannot be formed and the improved electrochemical properties of vanadium doped LiFePO 4 previously reported cannot be associated with crystal structure changes of the LiFePO 4 via vanadium doping. (orig.)

Stress induced reorientation of vanadium hydride

International Nuclear Information System (INIS)

Beardsley, M.B.

1977-10-01

The critical stress for the reorientation of vanadium hydride was determined for the temperature range 180 0 to 280 0 K using flat tensile samples containing 50 to 500 ppM hydrogen by weight. The critical stress was observed to vary from a half to a third of the macroscopic yield stress of pure vanadium over the temperature range. The vanadium hydride could not be stress induced to precipitate above its stress-free precipitation temperature by uniaxial tensile stresses or triaxial tensile stresses induced by a notch

Chemistry related to the procurement of vanadium alloys

International Nuclear Information System (INIS)

Smith, H.M.; Chung H.M.; Tsai, H.C.

1997-01-01

Evaluation of trace element concentrations in vanadium alloys is important to characterize the low-activation characteristics and possible effects of trace elements on the properties. Detailed chemical analysis of several vanadium and vanadium alloy heats procured for the Argonne vanadium alloy development program were analyzed by Johnson-Matthey (UK) as part of a joint activity to evaluate trace element effects on the performance characteristics. These heats were produced by normal production practices for high grade vanadium. The analyses include approximately 60 elements analyzed in most cases by glow-discharge mass spectrometry. Values for molybdenum and niobium, which are critical for low-activation alloys, ranged from 0.4 to 60 wppm for the nine heats

Chemistry related to the procurement of vanadium alloys

Energy Technology Data Exchange (ETDEWEB)

Smith, H.M.; Chung H.M.; Tsai, H.C. [Argonne National Lab., IL (United States)

1997-08-01

Evaluation of trace element concentrations in vanadium alloys is important to characterize the low-activation characteristics and possible effects of trace elements on the properties. Detailed chemical analysis of several vanadium and vanadium alloy heats procured for the Argonne vanadium alloy development program were analyzed by Johnson-Matthey (UK) as part of a joint activity to evaluate trace element effects on the performance characteristics. These heats were produced by normal production practices for high grade vanadium. The analyses include approximately 60 elements analyzed in most cases by glow-discharge mass spectrometry. Values for molybdenum and niobium, which are critical for low-activation alloys, ranged from 0.4 to 60 wppm for the nine heats.

Exploring electrolyte preference of vanadium nitride supercapacitor electrodes

Energy Technology Data Exchange (ETDEWEB)

Wang, Bo; Chen, Zhaohui; Lu, Gang [Department of Electrical Engineering and Automation, Luoyang Institute of Science and Technology, Luoyang 471023 (China); Wang, Tianhu [School of Electrical Information and Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Ge, Yunwang, E-mail: ywgelit@126.com [Department of Electrical Engineering and Automation, Luoyang Institute of Science and Technology, Luoyang 471023 (China)

2016-04-15

Highlights: • Hierarchical VN nanostructures were prepared on graphite foam. • Electrolyte preference of VN supercapacitor electrodes was explored. • VN showed better capacitive property in organic and alkaline electrolytes than LiCl. - Abstract: Vanadium nitride hierarchical nanostructures were prepared through an ammonia annealing procedure utilizing vanadium pentoxide nanostructures grown on graphite foam. The electrochemical properties of hierarchical vanadium nitride was tested in aqueous and organic electrolytes. As a result, the vanadium nitride showed better capacitive energy storage property in organic and alkaline electrolytes. This work provides insight into the charge storage process of vanadium nitride and our findings can shed light on other transition metal nitride-based electrochemical energy storage systems.

Complexation of vanadium with amidoxime and carboxyl groups. Uncovering the competitive role of vanadium in uranium extraction from seawater

Energy Technology Data Exchange (ETDEWEB)

Wang, Cong-Zhi; Wu, Qun-Yan; Lan, Jian-Hui; Shi, Wei-Qun [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics; Chai, Zhi-Fang [Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics; Soochow Univ., Suzhou (China). School of Radiological and Interdisciplinary Sciences (RAD-X); Wu, Guo-Zhong [Chinese Academy of Sciences, Shanghai (China). Shanghai Inst. of Applied Physics

2017-09-01

At present, amidoxime-based adsorbents are considered to be the most promising materials for extraction of uranium from seawater. However, the high concentrations of transition metals especially vanadium strongly compete with uranium in the sequestration process, which is extremely limited the commercial use of amidoxime-based adsorbents. In this work, the coordination modes, bonding nature, and stabilities of possible vanadium(IV) (VO{sup 2+}) and (V) (VO{sub 2}{sup +}, VO{sup 3+}, V{sup 5+}) complexes with amidoximate (AO{sup -}), carboxyl (Ac{sup -}), glutarimidedioximate (HA{sup -}) and deprotonated glutarimidedioximate (A{sup 2-}) on single and double alkyl chains (R=C{sub 13}H{sub 26}) are systematically explored by quantum chemical calculations. Different from the uranyl (UO{sub 2}{sup 2+}) complexes, the AO{sup -} groups of the vanadium(IV) and (V) complexes prefer to coordinate as monodentate and chelate ligands, while few species with AO{sup -} groups in η{sup 2}-binding mode have been observed in the vanadium complexes. Besides, the vanadium complexes are predicted to have obvious covalent metal-ligand bonds. According to thermodynamic stability analysis, all the vanadium complexes with AO{sup -}, Ac{sup -}, HA{sup -} and A{sup 2-} ligands on double alkyl chains are found to be more stable than corresponding complexes with ligands on a single chain. The synergistic effect of the amidoxime and carboxyl groups can be observed in most of VO{sub 2}{sup +} and VO{sup 3+} complexes with mixed ligands (AO{sup -}/Ac{sup -}). The vanadium(IV) and (V) complexes are more stable than the corresponding uranyl complexes, and the adsorption capability of the amidoxime-based adsorbents toward vanadium(V) ions decrease in the order of VO{sub 2}{sup +}>VO{sup 3+}> V{sup 5+}. The dioxovanadium cation VO{sub 2}{sup +} is predicted to form multinuclear vanadium complex in the sequestration process, possibly resulting in higher stable VO{sub 2}{sup +} complexes. Therefore

Enrichment, Distribution of Vanadium-Containing Protein in Vanadium-Enriched Sea Cucumber Apostichopus japonicus and the Ameliorative Effect on Insulin Resistance.

Science.gov (United States)

Liu, Yanjun; Zhou, Qingxin; Zhao, Yanlei; Wang, Yiming; Wang, Yuming; Wang, Jingfeng; Xu, Jie; Xue, Changhu

2016-05-01

Sea cucumbers are a potential source of natural organic vanadium that may improve insulin resistance. In this work, vanadium was accumulated rapidly in blood, body wall, and intestine by sea cucumber Apostichopus japonicus. Furthermore, water-soluble vanadium-containing proteins, the main form of the organic vanadium, were tentatively accumulated and isolated by a bioaccumulation experiment. It was also designed to evaluate the beneficial effect of vanadium-containing proteins (VCPs) from sea cucumber rich in vanadium on the development of hyperglycemia and insulin resistance in C57BL/6J mice fed with a high-fat high-sucrose diet (HFSD). HFSD mice treated with VCPs significantly decreased fasting blood glucose, serum insulin, and HOMA-IR values as compared to HFSD mice, respectively. Serum adiponectin, resistin, TNF-α, and leptin levels in insulin-resistant mice were dramatically reduced by a VCP supplement. These results show an ameliorative effect on insulin resistance by treatment with VCPs. Such compound seems to be a valuable therapy to achieve and/or maintain glycemic control and therapeutic agents in the treatment arsenal for insulin resistance and type 2 diabetes.

Vanadium and affective disorders

International Nuclear Information System (INIS)

Naylor, G.J.

1985-01-01

The oxidation reduction state of vanadium will influence its inhibitory effect, and it has been suggested that the control of this oxidation reduction could be a physiological means of controlling Na-K ATPase and hence membrane transport. However, there is no general agreement on this. For such a hypothesis to be true, tissue concentrations of vanadium would need to be sufficient to cause inhibition of Na-K ATPase. There has been considerable variation in the concentration of vanadium reported to be present in human blood and plasma - e.g., 8.4 μmoleliter, 0.11 μmoleliter, 0.04 μmoleliter and 0.0006-0.018 μmliter. Methods of assay have varied, even including enzymic methods, but the two major methods now used are neutron activation analysis and atomic absorption spectrophotometry using an electrical flameless atomizer. Using neutron activation analysis, difficulties arise from the short half-ife of V 52 (3.76 min) and for the need to separate Na 24 and Cl 36 from the sample since their radiation interfere with those from V 52 . Results from preirradiation separation agree well with those from atomic absorption spectrophotometry, but those from postirradiation separation are usually much lower. Though there is no agreement on the physiological role of vanadium there is evidence that it plays a part in the etiology of manic-depressive psychosis

Determination of vanadium (4) and (5) in the presence of both

International Nuclear Information System (INIS)

Malyuta, V.F.; Solomatin, V.T.; Berezhnoj, A.I.

1983-01-01

A study was made on the possibility of vanadium (4) and (5) determination in the presence of both by titration with ferrocene in aqueous solutions. 5-6 M H 2 SO 4 is the optimal medium for vanadium (5) titration. Vanadium (4) is titrated in the mixture of 2-2.5 M H 2 SO 4 and 8-10 M H 3 PO 4 . The method for vanadium (4) and (5) determination in vanadium catalysts was developed. Vanadium (5) is titrated amperometrically or potentiometrically by propanol solution of ferrocence in H 2 SO 4 . Concentrated H 3 PO 4 is added and the summary vanadium (4) is titrated. The relative standard deviations for 0.04-2% vanadium (4) content and 0.3-4% vanadium (5) content equal 0.06-0.03 and 0.05-0.02, respectively

Transformation and precipitation in vanadium treated steels

Science.gov (United States)

Vassiliou, Andreas D.

A series of carbon manganese steels containing varying amounts of carbon, vanadium and nitrogen was investigated in relation to the solubility of VC and VN in austenite, the grain coarsening characteristics of austenite, the tempering of martensite and other structures, the transformation during continuous cooling, the effect of vanadium addition and increasing nitrogen content on the thermo-mechanical processing of austenite, and the transformation of various morphologies of austenite to ferrite.The sites for preferential nucleation and growth of ferrite were identified and the effect of ferrite grain size inhomogeneity was investigated with a view to minimising it.The C/N ratio in the V(CN) precipitates was largely controlled by C/N ratio in the steel and it was also influenced by the austenitising treatment. As expected, the solubility of VN was less than that of VC.A systematic investigation of austenitising time and temperature on the grain coarsening characteristics was carried out showing the effects of vanadium, carbon and nitrogen. It was tentatively suggested that C-C and N-N clustering in the vanadium free steels controlled the grain growth whereas in the presence of vanadium, it was shown that VN and VC pinned the austenite grain boundaries and restricted grain growth. However coarsening or solution of VC and VN allowed the grain bondaries to migrate and grain coarsening occurred. The grain coarsening temperature was controlled predominantly by VN, whilst the VC dissolved frequently below the grain coarsening temperature.In the as quenched martensite, increasing nitrogen progressively increased the as quenched hardness, and the hardness also greatly increased with increasing carbon and vanadium added together. Examining the precipitation strengthening in tempered martensite showed that in the absence of vanadium, martensite softened progressively with increasing temperature and time. Vanadium additions increased the hardness level during low temperature

Phonon dispersion in vanadium

International Nuclear Information System (INIS)

Ivanov, A.S.; Rumiantsev, A.Yu.

1999-01-01

Complete text of publication follows. Phonon dispersion curves in Vanadium metal are investigated by neutron inelastic scattering using three-axis spectrometers. Due to extremely low coherent scattering amplitude of neutrons in natural isotope mixture of vanadium the phonon frequencies could be determined in the energy range below about 15 meV. Several phonon groups were measured with the polarised neutron scattering set-up. It is demonstrated that the intensity of coherent inelastic scattering observed in the non-spin-flip channel vanishes in the spin-flip channel. The phonon density of states is measured on a single crystal keeping the momentum transfer equal to a vector of reciprocal lattice where the coherent inelastic scattering is suppressed. Phonon dispersion curves in vanadium, as measured by neutron and earlier by X-ray scattering, are described in frames of a charge-fluctuation model involving monopolar and dipolar degrees of freedom. The model parameters are compared for different transition metals with body-centred cubic-structure. (author)

Low activation vanadium alloys

International Nuclear Information System (INIS)

Witzenburg, W. van.

1991-01-01

The properties and general characteristics of vanadium-base alloys are reviewed in terms of the materials requirements for fusion reactor first wall and blanket structures. In this review attention is focussed on radiation response including induced radioactivity, mechanical properties, compatibility with potential coolants, physical and thermal properties, fabricability and resources. Where possible, properties are compared to those of other leading candidate structural materials, e.g. austenitic and ferritic/martensitic steels. Vanadium alloys appear to offer advantages in the areas of long-term activation, mechanical properties at temperatures above 600 deg C, radiation resistance and thermo-hydraulic design, due to superior physical and thermal properties. They also have a potential for higher temperature operation in liquid lithium systems. Disadvantages are associated with their ability to retain high concentrations of hydrogen isotopes, higher cost, more difficult fabrication and welding. A particular concern regarding use of vanadium alloys relates their reactivity with non-metallic elements, such as oxygen and nitrogen. (author). 33 refs.; 2 figs.; 2 tabs

Pepspectives of chlorine application in metallurgy of vanadium

International Nuclear Information System (INIS)

Korshunov, B.G.; Kutsenko, S.A.

1983-01-01

The most expedient variants of reprocessing of vanadium technical oxide (5), ferrovanadium and converter slags by chlorine technology with production of pure metal are considered. It is shown that production of vanadium by the way of electro- or metallothermal reduction of chlorides provides more plastic metal in comparison with reduction from oxides. The methods of production of VOCl 3 , VCl 4 and vanadium lowest chlorides are considered. Necessity of expansion of production of vanadium chlorine derivatives is dictated as well by their increasing application in different areas of national economy, in particular, as catalysts in organic synthesis

Aqueous vanadium ion dynamics relevant to bioinorganic chemistry: A review.

Science.gov (United States)

Kustin, Kenneth

2015-06-01

Aqueous solutions of the four highest vanadium oxidation states exhibit four diverse colors, which only hint at the diverse reactions that these ions can undergo. Cationic vanadium ions form complexes with ligands; anionic vanadium ions form complexes with ligands and self-react to form isopolyanions. All vanadium species undergo oxidation-reduction reactions. With a few exceptions, elucidation of the dynamics of these reactions awaited the development of fast reaction techniques before the kinetics of elementary ligation, condensation, reduction, and oxidation of the aqueous vanadium ions could be investigated. As the biological roles played by endogenous and therapeutic vanadium expand, it is appropriate to bring the results of the diverse kinetics studies under one umbrella. To achieve this goal this review presents a systematic examination of elementary aqueous vanadium ion dynamics. Copyright © 2014 Elsevier Inc. All rights reserved.

Structural and silver/vanadium ratio effects on silver vanadium phosphorous oxide solution formation kinetics: impact on battery electrochemistry.

Science.gov (United States)

Bock, David C; Takeuchi, Kenneth J; Marschilok, Amy C; Takeuchi, Esther S

2015-01-21

The detailed understanding of non-faradaic parasitic reactions which diminish battery calendar life is essential to the development of effective batteries for use in long life applications. The dissolution of cathode materials including manganese, cobalt and vanadium oxides in battery systems has been identified as a battery failure mechanism, yet detailed dissolution studies including kinetic analysis are absent from the literature. The results presented here provide a framework for the quantitative and kinetic analyses of the dissolution of cathode materials which will aid the broader community in more fully understanding this battery failure mechanism. In this study, the dissolution of silver vanadium oxide, representing the primary battery powering implantable cardioverter defibrillators (ICD), is compared with the dissolution of silver vanadium phosphorous oxide (Ag(w)VxPyOz) materials which were targeted as alternatives to minimize solubility. This study contains the first kinetic analyses of silver and vanadium solution formation from Ag0.48VOPO4·1.9H2O and Ag2VP2O8, in a non-aqueous battery electrolyte. The kinetic results are compared with those of Ag2VO2PO4 and Ag2V4O11 to probe the relationships among crystal structure, stoichiometry, and solubility. For vanadium, significant dissolution was observed for Ag2V4O11 as well as for the phosphate oxide Ag0.49VOPO4·1.9H2O, which may involve structural water or the existence of multiple vanadium oxidation states. Notably, the materials from the SVPO family with the lowest vanadium solubility are Ag2VO2PO4 and Ag2VP2O8. The low concentrations and solution rates coupled with their electrochemical performance make these materials interesting alternatives to Ag2V4O11 for the ICD application.

Creep and creep rupture properties of unalloyed vanadium and solid-solution-strengthened vanadium-base alloys

International Nuclear Information System (INIS)

Kainuma, T.; Iwao, N.; Suzuki, T.; Watanabe, R.

1982-01-01

The creep and creep rupture properties of vanadium and vanadium-base alloys were studied at 700 and 1000 0 C. The alloys were vanadium-base binary alloys containing about 5 - 21 at.% Al, Ti, Nb, Ta, Cr, Mo or Fe, three V-20wt.%Nb-base ternary alloys containing 5 or 10 wt.% Al, Cr or Mo, V-10wt.%Ta-10wt.%Al and V-25wt.%Cr-0.8wt.%Zr. The creep rupture stress of the binary alloys, except the V-Al and V-Ti alloys, increased linearly with increasing concentration of the alloying elements. The V-Nb alloy had the best properties with respect to the rupture stress and creep rate at 700 0 C and the rupture stress at 1000 0 C, but the V-Mo alloy appeared likely to have better creep properties at longer times and higher temperatures. Of the five ternary alloys, V-20wt.%Nb-5wt.%Cr and V-20wt.%Nb-10wt.%Mo showed the best creep properties. The creep properties of these two alloys were compared with those of other vanadium alloys and of type 316 stainless steel. (Auth.)

Manufacturing development of low activation vanadium alloys

International Nuclear Information System (INIS)

Smith, J.P.; Johnson, W.R.; Baxi, C.B.

1996-10-01

General Atomics is developing manufacturing methods for vanadium alloys as part of a program to encourage the development of low activation alloys for fusion use. The culmination of the program is the fabrication and installation of a vanadium alloy structure in the DIII-D tokamak as part of the Radiative Divertor modification. Water-cooled vanadium alloy components will comprise a portion of the new upper divertor structure. The first step, procuring the material for this program has been completed. The largest heat of vanadium alloy made to date, 1200 kg of V-4Cr-4Ti, has been produced and is being converted into various product forms. Results of many tests on the material during the manufacturing process are reported. Research into potential fabrication methods has been and continues to be performed along with the assessment of manufacturing processes particularly in the area of joining. Joining of vanadium alloys has been identified as the most critical fabrication issue for their use in the Radiative Divertor Program. Joining processes under evaluation include resistance seam, electrodischarge (stud), friction and electron beam welding. Results of welding tests are reported. Metallography and mechanical tests are used to evaluate the weld samples. The need for a protective atmosphere during different welding processes is also being determined. General Atomics has also designed, manufactured, and will be testing a helium-cooled, high heat flux component to assess the use of helium cooled vanadium alloy components for advanced tokamak systems. The component is made from vanadium alloy tubing, machined to enhance the heat transfer characteristics, and joined to end flanges to allow connection to the helium supply. Results are reported

Mineralogy and geochemistry of vanadium in the Colorado Plateau

Science.gov (United States)

Weeks, A.D.

1961-01-01

The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

Vanadium bioavailability and toxicity to soil microorganisms and plants.

Science.gov (United States)

Larsson, Maja A; Baken, Stijn; Gustafsson, Jon Petter; Hadialhejazi, Golshid; Smolders, Erik

2013-10-01

Vanadium, V, is a redox-sensitive metal that in solution, under aerobic conditions, prevails as the oxyanion vanadate(V). There is little known regarding vanadium toxicity to soil biota, and the present study was set up to determine the toxicity of added vanadate to soil organisms and to investigate the relationship between toxicity and vanadium sorption in soils. Five soils with contrasting properties were spiked with 7 different doses (3.2-3200 mg V kg(-1)) of dissolved vanadate, and toxicity was measured with 2 microbial and 3 plant assays. The median effective concentration (EC50) thresholds of the microbial assays ranged from 28 mg added V kg(-1) to 690 mg added V kg(-1), and the EC50s in the plant assays ranged from 18 mg added V kg(-1) to 510 mg added V kg(-1). The lower thresholds were in the concentration range of the background vanadium in the untreated control soils (15-58 mg V kg(-1)). The vanadium toxicity to plants decreased with a stronger soil vanadium sorption strength. The EC50 values for plants expressed on a soil solution basis ranged from 0.8 mg V L(-1) to 15 mg V L(-1) and were less variable among soils than corresponding values based on total vanadium in soil. It is concluded that sorption decreases the toxicity of added vanadate and that soil solution vanadium is a more robust measure to determine critical vanadium concentrations across soils. © 2013 SETAC.

Optical spectra of vanadium (5, 4) compounds during extraction by di-2-ethylhexylphosphoric acid

International Nuclear Information System (INIS)

Kurbatova, L.D.; Medvedeva, N.I.

2000-01-01

Optical spectra of vanadium (5, 4) complexes with HDEHP are studied using literature data on quantum-chemical calculations of vanadium (5) and vanadium (4) oxides. Extraction of vanadium is conducted by undiluted HDEHP from sulfuric acid solutions. Absorption electron spectra (AES) of vanadium (5), vanadium (4) and vanadium (5, 4) compounds are presented. In AES of vanadium (5, 4) four absorption bands at 24000, 17000, 14500 and 13500 cm -1 appear. Comparison with spectra of vanadium (5) and vanadium (4) shows that band 17000 cm -1 which appears only during mutual extraction of vanadium (5) and vanadium (4) is caused by transitions appearing between filled and empty levels of d-zone broadened by vanadium (5) and vanadium (4) interaction [ru

Determination of Leachable Vanadium (V) in Sediment

African Journals Online (AJOL)

NICO

A method for speciation of vanadium in solid samples was developed for quantification of ... Experimental ... Sediments for Trace Metals), obtained from the National Research ... Determination of vanadium is not a simple task using ET-AAS.

Effect of vanadium compounds on acid phosphatase activity.

Science.gov (United States)

Vescina, C M; Sálice, V C; Cortizo, A M; Etcheverry, S B

1996-01-01

The direct effect of different vanadium compounds on acid phosphatase (ACP) activity was investigated. Vanadate and vanadyl but not pervanadate inhibited the wheat germ ACP activity. These vanadium derivatives did not alter the fibroblast Swiss 3T3 soluble fraction ACP activity. Using inhibitors of tyrosine phosphatases (PTPases), the wheat germ ACP was partially characterized as a PTPase. This study suggests that the inhibitory ability of different vanadium derivatives to modulate ACP activity seems to depend on the geometry around the vanadium atom more than on the oxidation state. Our results indicate a correlation between the PTPase activity and the sensitivity to vanadate and vanadyl cation.

Topotactic synthesis of vanadium nitride solid foams

International Nuclear Information System (INIS)

Oyama, S.T.; Kapoor, R.; Oyama, H.T.; Hofmann, D.J.; Matijevic, E.

1993-01-01

Vanadium nitride has been synthesized with a surface area of 120 m 2 g -1 by temperature programmed nitridation of a foam-like vanadium oxide (35 m 2 g -1 ), precipitated from vanadate solutions. The nitridation reaction was established to be topotactic and pseudomorphous by x-ray powder diffraction and scanning electron microscopy. The crystallographic relationship between the nitride and oxide was {200}//{001}. The effect of precursor geometry on the product size and shape was investigated by employing vanadium oxide solids of different morphologies

Recycling of Ammonia Wastewater During Vanadium Extraction from Shale

Science.gov (United States)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-03-01

In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4 + is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia wastewater leaching and crystallization during vanadium extraction from shale. The effects of the NH4 + concentration, temperature, time and liquid-to-solid ratio on the leaching efficiencies of vanadium, aluminum and potassium were investigated, and the results showed that 93.2% of vanadium, 86.3% of aluminum and 96.8% of potassium can be leached from sulfation-roasted shale. Subsequently, 80.6% of NH4 + was separated from the leaching solution via cooling crystallization. Vanadium was recovered via a combined method of solvent extraction, precipitation and calcination. Therefore, ammonia wastewater was successfully recycled during vanadium extraction from shale.

Nickel and vanadium extraction from the Syrian petroleum coke

International Nuclear Information System (INIS)

Shlewit, H.; Alibrahim, M.

2007-01-01

Syrian petroleum coke samples were characterized and submitted for salt-roasting treatment in electric furnace to evaluate the convenience of this procedure for the extraction of the vanadium, nickel and sulfur from coke. Both solution and solid residue remaining after salt roasting were separated by filtration and were analyzed for vanadium, nickel and sulfur. The solution was analyzed by UV-Visible spectroscopy for vanadium and nickel and gravimetrically for sulfur. The solid residue and the untreated samples of petroleum coke were analyzed by XRF spectrometry. Results showed that more than 90% of sulfur and 60% of vanadium could be extracted by salt roasting treatment. An alternative procedure has been suggested, in which, more than 80% of sulfur and small percentage of vanadium can be leached by 0.75 M of Na 2 CO 3 solution at 70-80 Co. Vanadium was selectively extracted by DEHPA/TBP from the loaded leached solution. The extraction procedure flowsheet was also suggested. (authors)

Vanadium Compounds as PTP Inhibitors

Directory of Open Access Journals (Sweden)

Elsa Irving

2017-12-01

Full Text Available Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs and protein tyrosine phosphatases (PTPs. Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

Vanadium extraction from slimes by the lime-bicarbonate method

International Nuclear Information System (INIS)

Lishchenko, T.V.; Vdovina, L.V.; Slobodchikova, R.I.

1978-01-01

Some main parameters of the lime-bicarbonate method of extracting vanadium from residues obtained in washing waters of mazut boilers on thermal stations have been determined. To study the process of vanadium extraction during caking of the residues with lime and subsequent leaching of water-soluble vanadium, a ''Minsk-22'' computer has been used for computation. Analysis of the equation derived has shown that a change in temperature of vanadium leaching, density of pulp, and a kind of heating of the charge affect the process only slightly. It has also been shown that the calcination temperature is expedient to be kept above 850 deg C and consumption temperature is expedient to be kept above 85O deg C and consumption of lime must not exceed 20% of the residues weight. Bicarbonate consumption exerts a decisive influence on completeness of vanadium extraction and must be increased up to >35%; duration of leaching should be raised up to 30-45 minutes. With increasing calcination temperature the duration of leaching decreases. When temperature and duration of calcination increase, the formation of water-soluble vanadium intensifies. With the aid of optimization program seven variants have been chosen, which ensure vanadium extraction into solution by 95-100%

Sensitivity Calculation of Vanadium Self-Powered Neutron Detector

International Nuclear Information System (INIS)

Cha, Kyoon Ho

2011-01-01

Self-powered neutron detector (SPND) is being widely used to monitor the reactor core of the nuclear power plants. The SPND contains a neutron-sensitive metallic emitter surrounded by a ceramic insulator. Currently, the rhodium SPND has been used in many nuclear power plants. The lifetime of rhodium is too short (about 3∼5 years) to operate the nuclear power plant economically. The vanadium (V) SPND is also primarily sensitive to neutrons like rhodium, but is a somewhat slower reaction time as that of a rhodium SPND. The benefit of vanadium over rhodium is its low depletion rate, which is a factor of 7 times less than that of rhodium. For this reason, a vanadium SPND has been being developed to replace the rhodium SPND which is used in OPR1000. Some Monte Carlo simulations were accomplished to calculate the initial sensitivity of vanadium emitter material and alumina (Al 2 O 3 ) insulator with a cylindrical geometry. An MCNP-X code was used to simulate some factors (neutron self shielding factor and electron escape probability from the emitter) necessary to calculate the sensitivity of vanadium detector. The simulation results were compared with some theoretical and experimental values. The method presented here can be used to analyze the optimum design of the vanadium SPND

Effect of vanadium compounds on acid phosphatase activity

OpenAIRE

Vescina, Cecilia M.; Sálice, Viviana C.; Cortizo, Ana María; Etcheverry, Susana B.

1996-01-01

The direct effect of different vanadium compounds on acid phosphatase (ACP) activity was investigated. Vanadate and vanadyl but not pervanadate inhibited the wheat germ ACP activity. These vanadium derivatives did not alter the fibroblast Swiss 3T3 soluble fraction ACP activity. Using inhibitors of tyrosine phosphatases (PTPases), the wheat germ ACP was partially characterized as a PTPase. This study suggests that the inhibitory ability of different vanadium derivatives to modulate ACP activi...

Vanadium carbide coatings: deposition process and properties

International Nuclear Information System (INIS)

Borisova, A.; Borisov, Y.; Shavlovsky, E.; Mits, I.; Castermans, L.; Jongbloed, R.

2001-01-01

Vanadium carbide coatings on carbon and alloyed steels were produced by the method of diffusion saturation from the borax melt. Thickness of the vanadium carbide layer was 5-15 μm, depending upon the steel grade and diffusion saturation parameters. Microhardness was 20000-28000 MPa and wear resistance of the coatings under conditions of end face friction without lubrication against a mating body of WC-2Co was 15-20 times as high as that of boride coatings. Vanadium carbide coatings can operate in air at a temperature of up to 400 o C. They improve fatigue strength of carbon steels and decrease the rate of corrosion in sea and fresh water and in acid solutions. The use of vanadium carbide coatings for hardening of various types of tools, including cutting tools, allows their service life to be extended by a factor of 3 to 30. (author)

Ion-exchange preparation of high-purity vanadium acid from industrial liquors

International Nuclear Information System (INIS)

Sajdakhmedov, U.A.; Arslanov, Sh.S.; Vulikh, A.I.

1994-01-01

The results of investigations on production of special-purity vanadium acid and vanadium oxide directly from process solutions (technical grade liquors) using ionites are presented. Potentiality of thorough purification of vanadium(5) oxide, when producing vanadium acid on the KU-2 cationite with subsequent purification on anionite, is shown. On the basis of the results obtained a principle flowsheet of ion-exchange production of high-purity vanadium(5) oxide from industrial liquors has been developed. 2 refs.; 1 fig.; 4 tabs

Vanadium research recharged

International Nuclear Information System (INIS)

Luntz, Stephen

2011-01-01

US President Barack Obama has described Maria Skyllas-Kazacos’ research as “one of the coolest things I’ve ever said out loud”. Vanadium redox batteries could be electricity’s ultimate storage mechanism.

Low-temperature direct synthesis of mesoporous vanadium nitrides for electrochemical capacitors

Energy Technology Data Exchange (ETDEWEB)

Lee, Hae-Min [Institute of NT-IT Fusion Technology, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon 16499 (Korea, Republic of); Jeong, Gyoung Hwa [Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Banyeon 100, Ulsan 44919 (Korea, Republic of); Kim, Sang-Wook [Department of Molecular Science and Technology, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon 16499 (Korea, Republic of); Kim, Chang-Koo, E-mail: changkoo@ajou.ac.kr [Department of Chemical Engineering and Department of Energy Systems Research, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon 16499 (Korea, Republic of)

2017-04-01

Highlights: • Vanadium nitrides were directly synthesized by a one-step chemical precipitation method. • This method was carried out at a low temperature of 70 °C. • Vanadium nitrides had a specific capacitance of 598 F/g. • The equivalent series resistance of the vanadium nitride electrode was 1.42 Ω after 5000 cycles. - Abstract: Mesoporous vanadium nitrides are directly synthesized by a one-step chemical precipitation method at a low temperature (70 °C). Structural and morphological analyses reveal that vanadium nitride consist of long and slender nanowhiskers, and mesopores with diameters of 2–5 nm. Compositional analysis confirms the presence of vanadium in the VN structure, along with oxidized vanadium. The cyclic voltammetry and charge-discharge tests indicate that the obtained material stores charges via a combination of electric double-layer capacitance and pseudocapacitance mechanisms. The vanadium nitride electrode exhibits a specific capacitance of 598 F/g at a current density of 4 A/g. After 5000 charge-discharge cycles, the electrode has an equivalent series resistance of 1.42 Ω and retains 83% of its initial specific capacitance. This direct low-temperature synthesis of mesoporous vanadium nitrides is a simple and promising method to achieve high specific capacitance and low equivalent series resistance for electrochemical capacitor applications.

Fatigue of vanadium--hydrogen alloys

International Nuclear Information System (INIS)

Lee, K.S.; Stoloff, N.S.

1975-01-01

Hydrogen contents near and above the room temperature solubility limit increase the high cycle fatigue life but decrease low cycle life of polycrystalline vanadium. Changes in endurance limit with hydrides may be a consequence of decreased cyclic strain hardening coefficient, n'. 132 ppM hydrogen in solution has only a slightly beneficial effect on stress controlled fatigue life and essentially no effect on low cycle fatigue life. Unalloyed vanadium exhibits profuse striations, while hydrides produce cleavage cracks in fatigued samples. 10 fig

Oxidative dehydrogenation of ethane over vanadium supported on mesoporous materials of M41S family

Czech Academy of Sciences Publication Activity Database

Čapek, J.; Adam, J.; Grygar, Tomáš; Bulánek, R.; Vradman, L.; Košová-Kučerová, G.; Čičmanec, P.; Knotek, P.

2008-01-01

Roč. 342, 1-2 (2008), s. 99-106 ISSN 0926-860X Grant - others:GA ČR(CZ) GP104/07/P038 Program:GP Institutional research plan: CEZ:AV0Z40320502 Keywords : oxidative dehydrogenation * ethane * vanadium * mesoporous materials Subject RIV: CA - Inorganic Chemistry Impact factor: 3.190, year: 2008

Oxidative Stress as a Mechanism Involved in Kidney Damage After Subchronic Exposure to Vanadium Inhalation and Oral Sweetened Beverages in a Mouse Model.

Science.gov (United States)

Espinosa-Zurutuza, Maribel; González-Villalva, Adriana; Albarrán-Alonso, Juan Carlos; Colín-Barenque, Laura; Bizarro-Nevares, Patricia; Rojas-Lemus, Marcela; López-Valdéz, Nelly; Fortoul, Teresa I

Kidney diseases have notably increased in the last few years. This is partially explained by the increase in metabolic syndrome, diabetes, and systemic blood hypertension. However, there is a segment of the population that has neither of the previous risk factors, yet suffers kidney damage. Exposure to atmospheric pollutants has been suggested as a possible risk factor. Air-suspended particles carry on their surface a variety of fuel combustion-related residues such as metals, and vanadium is one of these. Vanadium might produce oxidative stress resulting in the damage of some organs such as the kidney. Additionally, in countries like Mexico, the ingestion of sweetened beverages is a major issue; whether these beverages alone are responsible for direct kidney damage or whether their ingestion promotes the progression of an existing renal damage generates controversy. In this study, we report the combined effect of vanadium inhalation and sweetened beverages ingestion in a mouse model. Forty CD-1 male mice were distributed in 4 groups: control, vanadium inhalation, 30% sucrose in drinking water, and vanadium inhalation plus sucrose 30% in drinking water. Our results support that vanadium inhalation and the ingestion of 30% sucrose induce functional and histological kidney damage and an increase in oxidative stress biomarkers, which were higher in the combined effect of vanadium plus 30% sucrose. The results also support that the ingestion of 30% sucrose alone without hyperglycemia also produces kidney damage.

Determination of Vanadium Binding Mode on Seawater-Contacted Polyamidoxime Adsorbents

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhicheng [Lawrence Berkeley National Laboratory (LBNL); Rao, Linfeng [Lawrence Berkeley National Laboratory (LBNL); Abney, Carter W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryantsev, Vyacheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Aleksandr [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-09-01

Adsorbents developed for the recovery of uranium from seawater display poor selectivity over other transition metals present in the ocean, with vanadium particularly problematic. To improve selectivity, an indispensable step is the positive identification of metal binding environments following actual seawater deployment. In this work we apply x-ray absorption fine structure (XAFS) spectroscopy to directly investigate the vanadium binding environment on seawater-deployed polyamidoxime adsorbents. Comparison of the x-ray absorption near edge spectra (XANES) reveal marked similarities to recently a reported non-oxido vanadium (V) structure formed upon binding with cyclic imidedioxime, a byproduct of generating amidoxime functionalities. Density functional theory (DFT) calculations provided a series of putative vanadium binding environments for both vanadium (IV) and vanadium (V) oxidation states, and with both amidoxime and cyclic imidedioxime. Fits of the extended XAFS (EXAFS) data confirmed vanadium (V) is bound exclusively by the cyclic imidedioxime moiety in a 1:2 metal:ligand fashion, though a modest structural distortion is also observed compared to crystal structure data and computationally optimized geometries which is attributed to morphology effects from the polymer graft chain and the absence of crystal packing interactions. These results demonstrate that improved selectivity for uranium over vanadium can be achieved by suppressing the formation of cyclic imidedioxime during preparation of polyamidoxime adsorbents for seawater uranium recovery.

Vanadium dioxide formed by the sol-gel process

International Nuclear Information System (INIS)

Potember, R.S.; Speck, K.R.; Hu, H.S.

1990-01-01

This patent describes a process for the deposition of a crystalline vanadium dioxide thin film. It comprises: providing a solution comprising a vanadium tetraalkoxide and solvent; allowing hydrolysis and condensation reactions to progressively form a homogeneous sol from the solution, applying a coating of the sol to the substrate; allowing a gel to form from the sol on the substrate by evaporating the solvent; dehydrating the gel by heat treatment under an inert atmosphere to form the crystalline vanadium dioxide film

Experimental method for investigating helium effects in irradiated vanadium

International Nuclear Information System (INIS)

Smith, D.L.; Matsui, H.; Greenwood, L.; Loomis, B.

1987-10-01

Analyses have been performed which indicate that an effective method for experimentally investigating helium effects in neutron irradiated vanadium base alloys can be developed. The experimental procedure involves only modest modifications to existing procedures currently used for irradiation testing of vanadium-base alloys in the FFTF reactor. Helium is generated in the vanadium alloy by decay of tritium which is either preinjected or generated within the test capsule. Calculations indicate that nearly constant He/dpa ratios of desired magnitude can be attained by proper selection of experimental parameters. The proposed method could have a major impact on the development of vanadium base alloys for fusion reactor applications. 8 refs., 4 figs

Vanadium-base alloys for fusion reactor applications

International Nuclear Information System (INIS)

Smith, D.L.; Loomis, B.A.; Diercks, D.R.

1984-10-01

Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined

Vanadium-base alloys for fusion reactor applications

Energy Technology Data Exchange (ETDEWEB)

Smith, D.L.; Loomis, B.A.; Diercks, D.R.

1984-10-01

Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined.

Geochemistry of vanadium in an epigenetic, sandstone-hosted vanadium- uranium deposit, Henry Basin, Utah

Science.gov (United States)

Wanty, R.B.; Goldhaber, M.B.; Northrop, H.R.

1990-01-01

The epigenetic Tony M vanadium-uranium orebody in south-central Utah is hosted in fluvial sandstones of the Morrison Formation (Upper Jurassic). Measurements of the relative amounts of V+3 and V +4 in ore minerals show that V+3 is more abundant. Thermodynamic calculations show that vanadium was more likely transported to the site of mineralization as V+4. The ore formed as V+4 was reduced by hydrogen sulfide, followed by hydrolysis and precipitation of V+3 in oxide minerals or chlorite. Uranium was transported as uranyl ion (U+6), or some complex thereof, and reduced by hydrogen sulfide, forming coffinite. Detrital organic matter in the rocks served as the carbon source for sulfate-reducing bacteria. Vanadium most likely was derived from the dissolution of iron-titanium oxides. Uranium probably was derived from the overlying Brushy Basin Member of the Morrison Formation. Previous studies have shown that the ore formed at the density-stratified interface between a basinal brine and dilute meteoric water. The mineralization processes described above occurred within the mixing zone between these two fluids. -from Authors

Effect of drying method on properties of vanadium-molybdenum oxide catalysts

International Nuclear Information System (INIS)

Gorshkova, T.P.; Savchenko, L.A.; Tarasova, D.V.; Tret'yakov, Yu.D.; Olen'kova, I.P.; Nikoro, T.A.; Maksimov, N.G.

1981-01-01

Effect of drying method of molybdenum and vanadium salt solutions on physicochemical and catalytical properties of vanadium-molybdenum catalysts is studied. It is shown that the drying method of solutions determines the completeness of vanadium binding into oxide vanadium-molybdenum compounds and thus effects the activity and selectivity of catalysts in acrolein oxidation into acrylic acid. Besides the drying method determines the porous structure of catalysts [ru

Recent progress on gas tungsten arc welding of vanadium alloys

Energy Technology Data Exchange (ETDEWEB)

King, J.F.; Grossbeck, M.L.; Goodwin, G.M.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

1997-04-01

This is a progress report on a continuing research project to acquire a fundamental understanding of the metallurgical processes in the welding of vanadium alloys. It also has the goal of developing techniques for welding structural vanadium alloys. The alloy V-4Cr-4Ti is used as a representative alloy of the group; it is also the prime candidate vanadium alloy for the U.S. Fusion Program at the present time. However, other alloys of this class were used in the research as necessary. The present work focuses on recent findings of hydrogen embrittlement found in vanadium alloy welds. It was concluded that the atmosphere in the inert gas glove box was insufficient for welding 6mm thick vanadium alloy plates.

Absorption of hydrogen by vanadium-palladium alloys

International Nuclear Information System (INIS)

Artman, D.; Lynch, J.F.; Flanagan, T.B.

1976-01-01

Pressure composition isotherms (273-373 K) have been determined for the absorption of hydrogen by a series of six palladium alloys (f.c.c) in the composition range from 1 to 8 at.% vanadium. At a given hydrogen content, the equilibrium hydrogen pressure progressively increases with vanadium content. Thermodynamic parameters for the absorption of hydrogen are reported at infinite dilution of hydrogen and for the formation of the nonstoichiometric hydride from the hydrogen-saturated alloy. The relative, partial molar enthalpy of solution of hydrogen at infinite dilution increases slightly with vanadium content. The presence of vanadium, which absorbs hydrogen itself in its normal b.c.c. structure, greatly inhibits the ability of palladium to absorb hydrogen. For example, the isobaric solubility of hydrogen (1 atm, 298K) decreases from H/Pd=0.7 (palladium) to 0.024 (V(6%)-Pd). The lattice expansion due to the presence of interstitial hydrogen has been determined by X-ray diffraction. From these data it can be concluded that the formation of two non-stoichiometric hydride phases does not occur at vanadium contents greater that 5 at.% (298 K). Electrical resistance has been measured as a function of the hydrogen content of the alloys. The electrical resistance increases more markedly with hydrogen content for these alloys than for any of the palladium alloys previously examined. (Auth.)

Acute toxicity of vanadium to the threespine stickleback, Gasterosteus aculeatus

Energy Technology Data Exchange (ETDEWEB)

Gravenmier, J.J.; Johnston, D.W.; Arnold, W.R. [Blasland Bouck & Lee Inc, Petaluma, CA (US)

2005-02-15

Vanadium is widely distributed, occurring in many types of minerals, coal, and petroleum. Anthropogenic sources of vanadium originate from the production, processing, and wastes of these materials. The aquatic toxicity of vanadium to fish species is not well characterized. This study focused on the three-spined stickleback, Gasterosteus aculeatus, a small and widely distributed euryhaline species of fish. The three-spined stickleback is used as an effluent-monitoring species in both Canada and the United States. Five 96-h static renewal acute toxicity tests were performed in moderately hard water with adult fish. The geometric mean and range of the five 96-h LC{sup 50}s based on measured concentrations of total vanadium in the test solution were 3.17 and 2.35-4.07 mg V/L, respectively. A conservative estimation of a safe concentration of vanadium that would not affect survival of adult three-spined sticklebacks over a 96-h exposure period in moderately hard water is approximately 0.30 mg V/L. A comparison with other fish species previously tested suggests that the three-spined stickleback is intermediate in sensitivity to vanadium. Information reported from this study may be useful in effluent toxicity identification evaluations and ecological risk assessments related to vanadium.

TiAl doping by vanadium: ab initio study

International Nuclear Information System (INIS)

Smirnova, E.A.; Isaev, Eh.I.; Vekilov, Yu.Kh.

2004-01-01

Tetragonality degree in TiAl and vanadium doping effect on it were studied using the methods of calculation based on approximation of coherent potential and ab initio pseudopotentials. It is shown that vanadium substitution for Ti sublattice atoms entails increase in tetragonality degree but with substitution of the atoms in aluminium sublattice the tetragonality of the TiAl:V alloy decreases and at the content of vanadium about 8 at. % the lattice becomes actually cubical. In its turn, it may result in increase in TiAl ductility, the alloy being brittle at low temperatures [ru

Effects of hydrogen on fatigue of vanadium and niobium. Annual report

International Nuclear Information System (INIS)

Stoloff, N.S.; Chung, D.W.

1977-01-01

The fatigue behavior of unalloyed vanadium and niobium as well as their alloys with hydrogen is described. The response of vanadium-hydrogen alloys to cyclic loading is shown to depend markedly upon the presence or absence of notches, the hydrogen level, method of test, and frequency. In general, hydrides improve high cycle life of unnotched alloys, but are detrimental in the presence of a notch. Low test frequencies also lead to reduced fatigue lives. Stress-assisted hydride growth in previously hydrided alloys has been noted both in fatigue and in delayed failure experiments. Unalloyed vanadium and solid solution vanadium-hydrogen alloys do not undergo delayed failure. Preliminary tests on unalloyed niobium and several niobium-vanadium alloys reveal improvements in stress-controlled fatigue life and decreased low cycle life, in agreement with previous observations on vanadium-hydrogen alloys

Vanadium supply and demand outlook. Final report

International Nuclear Information System (INIS)

1978-01-01

A review has been made of the reserves and resources for vanadium minerals in the United States and foreign countries. Foreign sources are presently used to provide a substantial part of national demand because of price advantages. There are so many functioning foreign sources for vanadium that it is difficult to conceive of circumstances that would shut all of them off. The basis for the national stockpile is described. A recommendation is made to add the 65V-35Al alloy as a component of the stockpile for titanium alloy production in a national emergency. Estimated consumption growth rates to 1990 vary from one to five percent per year depending on the end product involved. Fission reactor use of vanadium-base alloys has not developed because of technical problems. In the chemical field, a slow steady growth of five to six percent per year is projected. Technical preferences for vanadium in various steel applications will continue although other alloying alternatives are generally available. Overall environmental effects do not appear to be a serious industrial problem

The vanadium/oxygen system in the analysis of sodium for oxygen

International Nuclear Information System (INIS)

Walker, J.A.J.; Price, W.B.

1981-05-01

An investigation of the V-O-Na system at 1023 K is described for oxygen in sodium contents of 5 to 25 ppm. Electron spectroscopy combined with depth profiling is used to determine the vanadium/oxygen ratios inwards from the surface of vanadium foil and these ratios are compared with theoretical predictions. The validity of the vanadium wire technique as an analytical method is examined and a model for the vanadium oxidation is suggested. (author)

Process of coke less without waste treatment of direct vanadium allowing steel melting

International Nuclear Information System (INIS)

Lisienko, V.G.; Droujinina, O.G.; Morozova, V.A.; Ladigina, N.V.; Yusfin, Yu.S.; Parenkev, A.E.

2003-01-01

The development of new methods of steel production are now conducted with the purpose of energy consumption and harmful emissions reduction. The choice of technology and equipment in this case plays a marginal role. It is well known that vanadium alloying steel has increased service properties. The known classical scheme of vanadium steel melting is very power-intensive, as includes such power-intensive processes as blast furnace process and chemical processing of vanadium slag therewith sintering and by-product coke processes are accompanied by significant harmful emissions. In so doing the vanadium losses may run to 60%. In view of requests of environment protection and economical efficiency the new process of coke less without wastes processing of vanadium-bearing raw material with direct vanadium allowing of steel - LP-process is developed. Its purpose is the melting on the basis of vanadium-bearing titanomagnetite of vanadium allowing steel with increase of vanadium concentration in steel and diminution of vanadium losses without application coke and natural gas with use of any coals and carbon-bearing wastes. LP-process consists of three aggregates and corresponding processes: process of liquid-phase reduction, process of vanadium-bearing pellets metallization in the shaft furnace, and process of alloying steel melting in the arc electric furnace. The obtained results have shown, that the LP-process is more energy saving on a comparison with other methods of vanadium allowing steel production. (Original)

TEM investigation of ductile iron alloyed with vanadium.

Science.gov (United States)

Dymek, S; Blicharski, M; Morgiel, J; Fraś, E

2010-03-01

This article presents results of the processing and microstructure evolution of ductile cast iron, modified by an addition of vanadium. The ductile iron was austenitized closed to the solidus (1095 degrees C) for 100 h, cooled down to 640 degrees C and held on at this temperature for 16 h. The heat treatment led to the dissolution of primary vanadium-rich carbides and their subsequent re-precipitation in a more dispersed form. The result of mechanical tests indicated that addition of vanadium and an appropriate heat treatment makes age hardening of ductile iron feasible. The precipitation processes as well as the effect of Si content on the alloy microstructure were examined by scanning and transmission electron microscopy. It was shown that adjacent to uniformly spread out vanadium-rich carbides with an average size of 50 nm, a dispersoid composed of extremely small approximately 1 nm precipitates was also revealed.

A novel comprehensive utilization of vanadium slag: As gamma ray shielding material

Energy Technology Data Exchange (ETDEWEB)

Dong, Mengge [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Liaoning Key Laboratory of Metallurgical Resources Recycling Science, Shenyang 110004 (China); Xue, Xiangxin, E-mail: xuexx@mail.neu.edu.cn [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Liaoning Key Laboratory of Metallurgical Resources Recycling Science, Shenyang 110004 (China); Yang, He; Liu, Dong [School of Metallurgy, Northeastern University, Shenyang 110004 (China); Liaoning Key Laboratory of Metallurgical Resources Recycling Science, Shenyang 110004 (China); Wang, Chao [Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Zhefu [Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2016-11-15

Highlights: • A novel comprehensive utilization method for vanadium slag is proposed. • Shielding properties of vanadium slag are better than ordinary concrete. • HVL of vanadium slag is between Lead and concrete to shield {sup 60}Co gamma ray. • HVL of composite is higher than concrete when adding amount of vanadium slag is 900. • Composite can be used as injecting mortar for cracks developed in concrete shields. - Abstract: New exploration of vanadium slag as gamma ray shielding material was proposed, the shielding properties of vanadium slag was higher than concrete when the energy of photons was in 0.0001 MeV–100000 MeV. Vanadium slag/epoxy resin composites were prepared, shielding and material properties of materials were tested by {sup 60}Co gamma ray, simultaneous DSC-TGA, electronic universal testing machine and scanning electron microscopy, respectively. The results showed that the shielding properties of composite would be better with the increase of vanadium slag addition amount. The HVL (half value layer thickness) of vanadium slag was between Lead and concrete while composite was higher than concrete when the addition amount of vanadium slag was 900 used as material to shield {sup 60}Co gamma ray, also the resistance temperature of composite was about 215 °C and the bending strength was over 10 MPa. The composites could be used as injecting mortar for cracks developed in biological concrete shields, coating for the floor of the nuclear facilities, and shielding materials by itself.

Hydrometallurgic treatment of a mineral containing uranium, vanadium and phosphorus

International Nuclear Information System (INIS)

Echenique, Patricia; Fruchtenicht, Fernando; Gil, Daniel; Vigo, Daniel; Bouza, Angel; Vert, Gabriela; Becquart, Elena

1987-01-01

A preliminary study of a mineral has been made towards the hydrometallurgy separation of uranium, vanadium and phosphorus. After the ore dressing, work on sulfuric acid with oxidation leaching has been made, to get the uranium, vanadium and phosphorus in solution. For the separation and purification of these elements, two alternative solvent extraction methods have been tested. One of them has been the extraction of uranium and vanadium and a selective stripping of both elements. The second one has been the selective extraction of uranium and vanadium at different aqueous solutions pH. In both methods, the same reagent has been used: di(2-ethylhexyl) phosphoric acid, kerosene as diluent with two different synergistic agents: TOPO (tri-n-octyl phosphine oxide) and TBP (tri-n-butyl phosphate). Batch studies have been made to determine the equilibrium isotherms for uranium and vanadium. A continuous countercurrent simulation method has been used to get the best phase ratio and to test different stripping agents. For the first method, an important loss of uranium and vanadium at the feed solution conditioning for the extraction step has been observed. For the second method, a good recovery of uranium has been reached, but there has been losses of vanadium in pH adjustment. Nevertheless, among these processes, the last seems to work better in this mineral hydrometallurgy. (Author) [es

Oxidation of methyl heterocyclic compounds on vanadium oxide catalysts

International Nuclear Information System (INIS)

Shimanskaya, M.V.; Lejtis, L.A.; Iovel', I.G.; Gol'dberg, Yu.Sh.; Skolmejstere, R.A.; Golender, L.O.

1985-01-01

Data on vapor-phase oxidation of methyl derivatives of thiophene, Δ 2 - thiazo line, pyridine, pyrazine and pyramidine on oxide vanadium-molybdenum catalysts to corresponding heterylaldehydes are generalized. The dependence of catalytic properties of oxide vanadium-molybdenum systems in oxidation reactions of methylheterocyclic compounds on V:Mo ratio in the catalyst is revealed. It is shown that heterocyclic compounds are coordinated by a heteroatom on Lewis centres of V-Mo-O-catalyst primarily with partially reduced vanadium ions

Vanadium and titanium determination by resorcinalhydrazide of salicylic acid

Energy Technology Data Exchange (ETDEWEB)

Karpova, O I; Pilipenko, A T; Lukachina, V V [AN Ukrainskoj SSR, Kiev. Inst. Kolloidnoj Khimii i Khimii Vody

1979-02-01

The complexing of titanium and vanadium with resorcinalhydrazyl of salicylic acid (RHSA) in water-organic media is studied. Titanium (4) forms a complex at pH 0.8-1.8, vanadium - at pH 2.5-5.6, and at pH 7.6-9.8. The complexes are well extracted by polar and nonpolar solvents from acid solutions. The techniques are developed for the determination of titanium and vanadium by the RHSA agent in nickel alloys.

Comparison of damage microstructures in neutron-irradiated vanadium and iron

International Nuclear Information System (INIS)

Horton, L.L.; Farrell, K.

1983-01-01

The cavity morphology and dislocation loop geometry in bcc vanadium are compared with the previously reported observations for neutron-irradiated iron. The specimens were vanadium (V) with 100 wppM of interstitial impurities and vanadium with boron carbide additions (V-B 4 C) which were irradiated to approx. 1 dpa in the same Oak Ridge Research Reactor capsules as the iron specimens

U.S. Contribution 1994 Summary Report Task T12: Compatibility and irradiation testing of vanadium alloys

International Nuclear Information System (INIS)

Smith, D.L.

1995-03-01

Vanadium alloys exhibit important advantages as a candidate structural material for fusion first wall/blanket applications. These advantages include fabricability, favorable safety and environmental features, high temperature and high wall load capability, and long lifetime under irradiation. Vanadium alloys with (3-5)% chromium and (3-5)% titanium appear to offer the best combination of properties for first wall/blanket applications. A V-4Cr-4Ti alloy is recommended as the reference composition for the ITER application. This report provides a summary of the R ampersand D conducted during 1994 in support of the ITER Engineering Design Activity. Progress is reported for Vanadium Alloy Production, Welding, Physical Properties, Baseline Mechanical Properties, Corrosion/Compatibility, Neutron Irradiation Effects, Helium Transmutation Effects on Irradiated Alloys, and the Status of Irradiation Experiments. Separate abstracts have been prepared for individual reports from this publication

U.S. Contribution 1994 Summary Report Task T12: Compatibility and irradiation testing of vanadium alloys

Energy Technology Data Exchange (ETDEWEB)

Smith, D.L. [comp.

1995-03-01

Vanadium alloys exhibit important advantages as a candidate structural material for fusion first wall/blanket applications. These advantages include fabricability, favorable safety and environmental features, high temperature and high wall load capability, and long lifetime under irradiation. Vanadium alloys with (3-5)% chromium and (3-5)% titanium appear to offer the best combination of properties for first wall/blanket applications. A V-4Cr-4Ti alloy is recommended as the reference composition for the ITER application. This report provides a summary of the R&D conducted during 1994 in support of the ITER Engineering Design Activity. Progress is reported for Vanadium Alloy Production, Welding, Physical Properties, Baseline Mechanical Properties, Corrosion/Compatibility, Neutron Irradiation Effects, Helium Transmutation Effects on Irradiated Alloys, and the Status of Irradiation Experiments. Separate abstracts have been prepared for individual reports from this publication.

Low-temperature direct synthesis of mesoporous vanadium nitrides for electrochemical capacitors

Science.gov (United States)

Lee, Hae-Min; Jeong, Gyoung Hwa; Kim, Sang-Wook; Kim, Chang-Koo

2017-04-01

Mesoporous vanadium nitrides are directly synthesized by a one-step chemical precipitation method at a low temperature (70 °C). Structural and morphological analyses reveal that vanadium nitride consist of long and slender nanowhiskers, and mesopores with diameters of 2-5 nm. Compositional analysis confirms the presence of vanadium in the VN structure, along with oxidized vanadium. The cyclic voltammetry and charge-discharge tests indicate that the obtained material stores charges via a combination of electric double-layer capacitance and pseudocapacitance mechanisms. The vanadium nitride electrode exhibits a specific capacitance of 598 F/g at a current density of 4 A/g. After 5000 charge-discharge cycles, the electrode has an equivalent series resistance of 1.42 Ω and retains 83% of its initial specific capacitance. This direct low-temperature synthesis of mesoporous vanadium nitrides is a simple and promising method to achieve high specific capacitance and low equivalent series resistance for electrochemical capacitor applications.

Complexing of vanadium(3) with chromotropic acid derivatives

International Nuclear Information System (INIS)

Babenko, N.L.; Busev, A.I.; Sukhorukova, N.V.; Frolova, O.S.

1976-01-01

A spectrophotometric study has been made of the complex formation of vanadium (3) with arsenazo(1), arsenazo(3) and some monosubstituted derivatives of chromotropic acid and sulphanylamides. In acid medium vanadium (3) reacts with each of these reagents to produce a 1:1 complex. Optimum conditions of the complex formation was found. The effect of H + on the complex formation of vanadium (3) with chromotropic acid derivatives was established. It was found by the graphical method that the formation of the complex is accompanied by the elimination of one proton. Patterns were found of the influence of the nature of substituents in the organic compound on the ionization constants of acid groups and stability of complexes. Molar extinction coefficients, equilibrium constants of the formation reactions and instability constants for the complexes were calculated. The structure of complexes was suggested. Similar behaviour of all the reagents was established in the complex formation with vanadium (3)

Nanostructured Electrocatalysts for All-Vanadium Redox Flow Batteries.

Science.gov (United States)

Park, Minjoon; Ryu, Jaechan; Cho, Jaephil

2015-10-01

Vanadium redox reactions have been considered as a key factor affecting the energy efficiency of the all-vanadium redox flow batteries (VRFBs). This redox reaction determines the reaction kinetics of whole cells. However, poor kinetic reversibility and catalytic activity towards the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples on the commonly used carbon substrate limit broader applications of VRFBs. Consequently, modified carbon substrates have been extensively investigated to improve vanadium redox reactions. In this Focus Review, recent progress on metal- and carbon-based nanomaterials as an electrocatalyst for VRFBs is discussed in detail, without the intention to provide a comprehensive review on the whole components of the system. Instead, the focus is mainly placed on the redox chemistry of vanadium ions at a surface of various metals, different dimensional carbons, nitrogen-doped carbon nanostructures, and metal-carbon composites. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tackling capacity fading in vanadium flow batteries with amphoteric membranes

Science.gov (United States)

Oldenburg, Fabio J.; Schmidt, Thomas J.; Gubler, Lorenz

2017-11-01

Capacity fading and poor electrolyte utilization caused by electrolyte imbalance effects are major drawbacks for the commercialization of vanadium flow batteries (VFB). The influence of membrane type (cationic, anionic, amphoteric) on these effects is studied by determining the excess and net flux of each vanadium ion in an operating VFB assembled with a cation exchange membrane (CEM), Nafion® NR212, an anion exchange membrane (AEM), Fumatech FAP-450, and an amphoteric ion exchange membrane (AIEM) synthesized in-house. It is shown that the net vanadium flux, accompanied by water transport, is directed towards the positive side for the CEM and towards the negative side for the AEM. The content of cation and anion exchange groups in the AIEM is adjusted via radiation grafting to balance the vanadium flux between the two electrolyte sides. With the AIEM the net vanadium flux is significantly reduced and capacity fading due to electrolyte imbalances can be largely eliminated. The membrane's influence on electrolyte imbalance effects is characterized and quantified in one single charge-discharge cycle by analyzing the content of the four different vanadium species in the two electrolytes. The experimental data recorded herewith conclusively explains the electrolyte composition after 80 cycles.

Vanadium bioavailability and toxicity to soil microorganisms and plants

OpenAIRE

Larsson, Maja A; Baken, Stijn; Gustafsson, Jon Petter; Hadialhejazi, Golshid; Smolders, Erik

2013-01-01

Vanadium, V, is a redox-sensitive metal that in solution, under aerobic conditions, prevails as the oxyanion vanadate(V). There is little known regarding vanadium toxicity to soil biota, and the present study was set up to determine the toxicity of added vanadate to soil organisms and to investigate the relationship between toxicity and vanadium sorption in soils. Five soils with contrasting properties were spiked with 7 different doses (3.2-3200mgVkg(-1)) of dissolved vanadate, and toxicity ...

Study on the poisoning effect-of non-vanadium catalysts by potassium

Science.gov (United States)

Zeng, Huanmu; Liu, Ying; Yu, Xiaowei; Lin, Yasi

2018-02-01

The poisoning effect of catalyst by alkali metals is one of the problems in the selective catalytic reduction (SCR) of NO by NH3. Serious deactivation by alkali poisoning have been proved to take place in the commercial vanadium catalyst. Recently, non-vanadium catalysts such as copper oxides, manganese oxides, chromium oxides and cerium oxides have attracted special attentions in SCR application. However, their tolerance in the presence of alkali metals is still doubtful. In this paper, copper oxides, manganese oxides, chromium oxides and cerium oxides supported on TiO2 nanoparticle was prepared by impregnating method. Potassium nitrate was chosen as the precursor of poisoner. Catalytic activities of these catalysts were evaluated before and after the addition of potassium. Some characterization methods including X-ray diffraction and temperature programmed desorption was utilized to reveal the main reason of alkali deactivation.

Effectively suppressing vanadium permeation in vanadium redox flow battery application with modified Nafion membrane with nacre-like nanoarchitectures

Science.gov (United States)

Zhang, Lesi; Ling, Ling; Xiao, Min; Han, Dongmei; Wang, Shuanjin; Meng, Yuezhong

2017-06-01

A novel self-assembled composite membrane, Nafion-[PDDA/ZrP]n with nacre-like nanostructures was successfully fabricated by a layer-by-layer (LbL) method and used as proton exchange membrane for vanadium redox flow battery applications. Poly(diallyldimethylammonium chloride) (PDDA) with positive charges and zirconium phosphate (ZrP) nanosheets with negative charges can form ultra-thin nacre-like nanostructure on the surface of Nafion membrane via the ionic crosslinking of tightly folded macromolecules. The lamellar structure of ZrP nanosheets and Donnan exclusion effect of PDDA can greatly decrease the vanadium ion permeability and improve the selectivity of proton conductivity. The fabricated Nafion-[PDDA/ZrP]4 membrane shows two orders of magnitude lower vanadium ion permeability (1.05 × 10-6 cm2 min-1) and 12 times higher ion selectivity than those of pristine Nafion membrane at room temperature. Consequently, the performance of vanadium redox flow batteries (VRFBs) assembled with Nafion-[PDDA/ZrP]3 membrane achieved a highly coulombic efficiency (CE) and energy efficiency (EE) together with a very slow self-discharge rate. When comparing with pristine Nafion VRFB, the CE and EE values of Nafion-[PDDA/ZrP]3 VRFB are 10% and 7% higher at 30 mA cm-2, respectively.

Thermal conductivity of high purity vanadium

International Nuclear Information System (INIS)

Jung, W.D.

1975-01-01

The thermal conductivity, Seebeck coefficient, and electrical resistivity of four high-purity vanadium samples were measured over the temperature range 5 to 300 0 K. The highest purity sample had a resistance ratio (rho 273 /rho 4 . 2 ) of 1524. The highest purity sample had a thermal conductivity maximum of 920 W/mK at 9 0 K and had a thermal conductivity of 35 W/mK at room temperature. At low temperatures, the thermal resistivity was limited by the scattering of electrons by impurities and phonons. The thermal resistivity of vanadium departed from Matthiessen's rule at low temperatures. The electrical resistivity and Seebeck coefficient of high purity vanadium showed no anomalous behavior above 130 0 K. The intrinsic electrical resistivity at low temperatures was due primarily to interband scattering of electrons. The Seebeck coefficient was positive from 10 to 240 0 K and had a maximum which was dependent upon sample purity

Fundamental aspects of alluminothermic reduction of vanadium pentoxide

International Nuclear Information System (INIS)

Mourao, M.B.; Capocchi, J.D.T.

1982-01-01

The aluminothermic process for the reduction of vanadium pentoxide is considered. Its thermochemistry features are presented, as well as the heat transfer and the rate phenomena concerning such a reaction system. It is pointed out also the effect of the process parameters on the recovery of metallic vanadium. (Author) [pt

Vanadium Recovery from Oil Fly Ash by Carbon Removal and Roast-Leach Process

Science.gov (United States)

Jung, Myungwon; Mishra, Brajendra

2018-02-01

This research mainly focuses on the recovery of vanadium from oil fly ash by carbon removal and the roast-leach process. The oil fly ash contained about 85% unburned carbon and 2.2% vanadium by weight. A vanadium-enriched product was obtained after carbon removal, and the vanadium content of this product was 19% by weight. Next, the vanadium-enriched product was roasted with sodium carbonate to convert vanadium oxides to water-soluble sodium metavanadate. The roasted sample was leached with water at 60°C, and the extraction percentage of vanadium was about 92% by weight. Several analytical techniques, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES), x-ray fluorescence (XRF), and thermogravimetric and differential thermal analysis (TG-DTA), were utilized for sample analyses. Thermodynamic modeling was also conducted with HSC chemistry software to explain the experimental results.

Temperature dependence of the damage microstructures in neutron-irradiated vanadium

International Nuclear Information System (INIS)

Horton, L.L.; Farrell, K.

1983-01-01

Vanadium and vanadium with boron carbide additions (V-B 4 C) were irradiated to approx. 1 dpa in the Oak Ridge Research Reactor at controlled temperatures ranging from 455 to 925 K. The V-B 4 C alloy was enriched in 10 B, which produced approx. 3900 at. ppM helium. In the vanadium specimens, the dislocation microstructures varied from clusters of small ( . The V-B 4 C specimens contained only tangled dislocation segments. Cavities were observed in all specimens. The cavity concentration decrease and the average diameter increased with increasing irradiation temperature. At 725 K, the maximum swelling was observed in both the vanadium (0.1%) and V-B 4 C (1.4%). At comparable temperatures the cavities in the V-B 4 C specimens were smaller and more numerous than those in the vanadium specimens. Helium bubbles were found on the grain boundaries in all of the V-B 4 specimens

Vanadium Extraction from Shale via Sulfuric Acid Baking and Leaching

Science.gov (United States)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-01-01

Fluorides are widely used to improve vanadium extraction from shale in China. Sulfuric acid baking-leaching (SABL) was investigated as a means of recovering vanadium which does not require the use of fluorides and avoids the productions of harmful fluoride-containing wastewater. Various effective factors were systematically studied and the experimental results showed that 90.1% vanadium could be leached from the shale. On the basis of phase transformations and structural changes after baking the shale, a mechanism of vanadium extraction from shale via SABL was proposed. The mechanism can be described as: (1) sulfuric acid diffusion into particles; (2) the formation of concentrated sulfuric acid media in the particles after water evaporation; (3) hydroxyl groups in the muscovite were removed and transient state [SO4 2-] was generated; and (4) the metals in the muscovite were sulfated by active [SO4 2-] and the vanadium was released. Thermodynamics modeling confirmed this mechanism.

Directed synthesis of bio-inorganic vanadium oxide composites using genetically modified filamentous phage

International Nuclear Information System (INIS)

Mueller, Michael; Baik, Seungyun; Jeon, Hojeong; Kim, Yuchan; Kim, Jungtae; Kim, Young Jun

2015-01-01

Highlights: • Phage is an excellent seeding for bio-templates for environmentally benign vanadium oxide nanocomposite synthesis. • The synthesized bio-inorganic vanadium oxide showed photodegradation activities. • The fabricated wt phage/vanadium oxide composite exhibited bundle-like structure. • The fabricated RSTB-phage/vanadium oxide composite exhibited a ball with a fiber-like nanostructure. • The virus/vanadium oxide composite could be applied in photocatalysts, sensors and nanoelectronic applications. - Abstract: The growth of crystalline vanadium oxide using a filamentous bacteriophage template was investigated using sequential incubation in a V 2 O 5 precursor. Using the genetic modification of the bacteriophage, we displayed two cysteines that constrained the RSTB-1 peptide on the major coat protein P8, resulting in vanadium oxide crystallization. The phage-driven vanadium oxide crystals with different topologies, microstructures, photodegradation and vanadium oxide composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz microbalance and dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). Non-specific electrostatic attraction between a wild-type phage (wt-phage) and vanadium cations in the V 2 O 5 precursor caused phage agglomeration and fiber formation along the length of the viral scaffold. As a result, the addition of recombinant phage (re-phage) in V 2 O 5 precursors formed heterogeneous structures, which led to efficient condensation of vanadium oxide crystal formation in lines, shown by QCM-D analysis. Furthermore, re-phage/V x O x composites showed significantly enhanced photodegradation activities compared with the synthesized wt-phage-V 2 O 5 composite under illumination. This study demonstrates that peptide-mediated vanadium oxide mineralization is governed by a complicated interplay of peptide sequence, local structure, kinetics and the presence of a mineralizing

Highly stable pyridinium-functionalized cross-linked anion exchange membranes for all vanadium redox flow batteries

Science.gov (United States)

Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

2016-11-01

It has recently been demonstrated that the use of anion exchange membranes (AEMs) in vanadium redox flow batteries (VRFBs) can reduce the migration of vanadium ions through the membrane due to the Donnan exclusion effect among the positively charged functional groups and vanadium ions. However, AEMs are plagued by low chemical stability in harsh chemical environments. Here we propose and fabricate a pyridinium-functionalized cross-linked AEM for VRFBs. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. Therefore, the membrane exhibits littler decay in a harsh environment for 20 days during the course of an ex situ immersion test. A cycling test also demonstrates that the VRFB assembled with the membrane enable to retain 80% of the initial discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle-1. Meanwhile, the membrane also shows a low vanadium permeability and a reasonably high conductivity in supporting electrolytes. Hence, all the measurements and performance tests reported in this work suggest that the membrane is a promising AEM for redox flow batteries to achieve excellent cycling stability and superior cell performance.

Calculations of oscillation spectra of disordered interstitial solid solutions of vanadium-oxygen system

International Nuclear Information System (INIS)

Danilkin, S.A.

1978-01-01

The frequency spectra calculation of disordered solid interstitial solutions of a vanadium-oxygen system for oxygen concentration of 5.9% and 15.8% (V 16 O and V 16 O 3 ) is carried out. The axially-symmetric model of crystal lattice dinamics with consideration of vanadium-oxygen and vanadium-vanadium interactions up to the second coordination sphere is used. On the whole, the obtained spectra are in qualitative agreement with experiment and reflect correctly all the changes in frequency spectra of pure vanadium on doping with oxygen

Spectrophotometric determination of vanadium in environmental and biological samples

International Nuclear Information System (INIS)

Rekha, D.; Krishnapriya, B.; Subrahmanyam, P.; Reddyprasad, P.; Dilip Kumar, J.; Chiranjeevi, P.

2007-01-01

The method is based on oxidation of p-nitro aniline by vanadium (V) followed by coupling reaction with N-(1-naphthalene-1-y1)ethane-1, 2-diaminedihydrochloride (NEDA) in basic medium of pH 8 to give purple colored derivative. The derivative having an λ max 525nm is stable for 10 days. Beer's law is obeyed for vanadium (V) in the concentration range of 0.03-4.5 μg ml -1 . The proposed method was successfully applied to the analysis of vanadium in environmental and biological samples. (author)

Iron diminishes the in vitro biological effect of vanadium.

Science.gov (United States)

Mechanistic pathways underlying inflammatory injury following exposures to vanadium-containing compounds are not defined. We tested the postulate that the in vitro biological effect of vanadium results from its impact on iron homeostasis. Human bronchial epithelial (HBE) cells ex...

Amphoteric Ion-Exchange Membranes with Significantly Improved Vanadium Barrier Properties for All-Vanadium Redox Flow Batteries.

Science.gov (United States)

Nibel, Olga; Rojek, Tomasz; Schmidt, Thomas J; Gubler, Lorenz

2017-07-10

All-vanadium redox flow batteries (VRBs) have attracted considerable interest as promising energy-storage devices that can allow the efficient utilization of renewable energy sources. The membrane, which separates the porous electrodes in a redox flow cell, is one of the key components in VRBs. High rates of crossover of vanadium ions and water through the membrane impair the efficiency and capacity of a VRB. Thus, membranes with low permeation rate of vanadium species and water are required, also characterized by low resistance and stability in the VRB environment. Here, we present a new design concept for amphoteric ion-exchange membranes, based on radiation-induced grafting of vinylpyridine into an ethylene tetrafluoroethylene base film and a two-step functionalization to introduce cationic and anionic exchange sites, respectively. During long-term cycling, redox flow cells containing these membranes showed higher efficiency, less pronounced electrolyte imbalance, and significantly reduced capacity decay compared to the cells with the benchmark material Nafion 117. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The structural studies of vanadium substituted lithium-bismuth-boro-tellurite glass

Science.gov (United States)

Madhu, A.; Eraiah, B.

2018-05-01

The structural studies of vanadium substituted lithium-bismuth-boro-tellurite glass is successfully prepared and certain analysis like XRD,FTIR,DTA/TGA with density, molar volume are done. The amorphous phase has been identified based on X-ray diffraction analysis. The vanadium oxide plays the role as a glass-modifier and influences on BO3 ↔ BO4 conversion. The observed nonlinear variation in Tg with vanadium oxide increase, it reflects structural changes. The nonlinear variation of density and molar volume can be attributed to vanadium oxide incorporation have increased the number of Non-bridging oxygen (NBO'S).

Ferrocenometric deterrination of vanadium and iron in the presence of each other

International Nuclear Information System (INIS)

Malyuta, V.F.; Solomatin, V.T.; Nemodruk, A.A.

1983-01-01

Real redox potentials have been measured for the V(4)/V(3), Fe(3)/Fe(2) and Fec + /Fec systems in HCl-H 3 PO 4 and H 2 SO 4 -H 3 PO 4 aqueous solutions. The mechanism is suggested for the reduction of vanadium (4) with ferrocene in the presence of iron (3). The possibility has been shown of differential titration of vanadium (4) and iron (3) by ferrocene in the presence of each other in aqueous solutions. A procedure of determining vanadium in steel and a procedure of determining vanadium and iron in ferrovanadium, vanadium slags and cobalt-based alloys have been worked out by the method of potentiometric and amperometric titration with ferrocene solution

Positron lifetime in vanadium oxide bronzes

International Nuclear Information System (INIS)

Dryzek, J.; Dryzek, E.

2003-01-01

The positron lifetime (PL) and Doppler broadening (DB) of annihilation line measurements have been performed in vanadium oxide bronzes M x V 2 O 5 . The dependence of these annihilation characteristics on the kind and concentration of the metal M donor has been observed. In the PL spectrum only one lifetime component has been detected in all studied bronzes. The results indicate the positron localization in the structural tunnels present in the crystalline lattice of the vanadium oxide bronzes. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Vanadium alloys for fusion reactor applications

International Nuclear Information System (INIS)

Mattas, R.F.; Loomis, B.A.; Smith, D.L.

1992-01-01

This paper reports that fusion reactors will produce a severe operating environment for structural materials. The material should have good mechanical strength and ductility to high temperature, be corrosion resistant to the local environment, have attractive thermophysical properties to accommodate high heat loads, and be resistant to neutron damage. Vanadium alloys are being developed for such applications, and they exhibit desirable properties in many areas Recent progress in vanadium alloy development indicates good strength and ductility to 700 degrees C, minimal degradation by neutron irradiation, and reduced radioactivity compared with other candidate alloy systems

Compatibility of niobium, titanium, and vanadium metals with LMFBR cladding

International Nuclear Information System (INIS)

Wilson, C.N.

1975-10-01

A series of laboratory capsule annealing experiments were conducted to assess the compatibility of niobium, vanadium, and titanium with 316 stainless steel cladding in the temperature range of 700 to 800 0 C. Niobium, vanadium, and titanium are cantidate oxygen absorber materials for control of oxygen chemistry in LMFBR fuel pins. Capsule examination indicated good compatibility between niobium and 316 stainless steel at 800 0 C. Potential compatibility problems between cladding and vanadium or titanium were indicated at 800 0 C under reducing conditions. In the presence of Pu/sub 0.25/U/sub 0.75/O/sub 1.98/ fuel (Δanti G 02 congruent to -160 kcal/mole) no reaction was observed between vanadium or titanium and cladding at 800 0 C

Directed synthesis of bio-inorganic vanadium oxide composites using genetically modified filamentous phage

Energy Technology Data Exchange (ETDEWEB)

Mueller, Michael; Baik, Seungyun [Environmental Safety Group, Korea Institute of Science and Technology Europe (KIST-Europe) Forschungsgesellschaft mbH, Campus E 7 1, Saarbruecken (Germany); Jeon, Hojeong; Kim, Yuchan [Center for Biomaterials, Biomedical Research Institute Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, Jungtae [Environmental Safety Group, Korea Institute of Science and Technology Europe (KIST-Europe) Forschungsgesellschaft mbH, Campus E 7 1, Saarbruecken (Germany); Kim, Young Jun, E-mail: youngjunkim@kist-europe.de [Environmental Safety Group, Korea Institute of Science and Technology Europe (KIST-Europe) Forschungsgesellschaft mbH, Campus E 7 1, Saarbruecken (Germany)

2015-05-15

Highlights: • Phage is an excellent seeding for bio-templates for environmentally benign vanadium oxide nanocomposite synthesis. • The synthesized bio-inorganic vanadium oxide showed photodegradation activities. • The fabricated wt phage/vanadium oxide composite exhibited bundle-like structure. • The fabricated RSTB-phage/vanadium oxide composite exhibited a ball with a fiber-like nanostructure. • The virus/vanadium oxide composite could be applied in photocatalysts, sensors and nanoelectronic applications. - Abstract: The growth of crystalline vanadium oxide using a filamentous bacteriophage template was investigated using sequential incubation in a V{sub 2}O{sub 5} precursor. Using the genetic modification of the bacteriophage, we displayed two cysteines that constrained the RSTB-1 peptide on the major coat protein P8, resulting in vanadium oxide crystallization. The phage-driven vanadium oxide crystals with different topologies, microstructures, photodegradation and vanadium oxide composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz microbalance and dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). Non-specific electrostatic attraction between a wild-type phage (wt-phage) and vanadium cations in the V{sub 2}O{sub 5} precursor caused phage agglomeration and fiber formation along the length of the viral scaffold. As a result, the addition of recombinant phage (re-phage) in V{sub 2}O{sub 5} precursors formed heterogeneous structures, which led to efficient condensation of vanadium oxide crystal formation in lines, shown by QCM-D analysis. Furthermore, re-phage/V{sub x}O{sub x} composites showed significantly enhanced photodegradation activities compared with the synthesized wt-phage-V{sub 2}O{sub 5} composite under illumination. This study demonstrates that peptide-mediated vanadium oxide mineralization is governed by a complicated interplay of peptide sequence, local structure

mu(2)-Oxido bridged dinuclear vanadium(V) complex: synthesis and characterization

Czech Academy of Sciences Publication Activity Database

Ghorbani, M.; Khalaji, A.D.; Feizi, N.; Akbari, A.; Eigner, Václav; Dušek, Michal

2017-01-01

Roč. 1130, Feb (2017), s. 442-446 ISSN 0022-2860 R&D Projects: GA ČR(CZ) GA15-12653S; GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : vanadium(V) complex * Schiff base * dinuclear * octahedral Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 1.753, year: 2016

Application of vanadium alloys to a fusion reactor blanket

Energy Technology Data Exchange (ETDEWEB)

Bethin, J.; Tobin, A. (Grumman Aerospace Corp., Bethpage, NY (USA). Research and Development Center)

1984-05-01

Vanadium and vanadium alloys are of interest in fusion reactor blanket applications due to their low induced radioactivity and outstanding elevated temperature mechanical properties during neutron irradiation. The major limitation to the use of vanadium is its sensitivity to oxygen impurities in the blanket environment, leading to oxygen embrittlement. A quantitative analysis was performed of the interaction of gaseous impurities in a helium coolant with vanadium and the V-15Cr-5Ti alloy under conditions expected in a fusion reactor blanket. It was shown that the use of unalloyed V would impose severe restrictions on the helium gas cleanup system due to excessive oxygen buildup and embrittlement of the metal. However, internal oxidation effects and the possibly lower terminal oxygen solubility in the alloy would impose much less severe cleanup constraints. It is suggested that V-15Cr-5Ti is a promising candidate for certain blanket applications and deserves further consideration.

The bioinorganic electrochemistry of vanadium-penicillamine complexes

International Nuclear Information System (INIS)

Bagal, U.A.; Riechel, T.L.

1989-01-01

Vanadium (V) has been found to inhibit (Na + , K + )-ATPase in the sodium pump reaction in erythrocytes. Glutathione has been suggested as the reducing agent that reverses the effect by reducing vanadium to the (IV) oxidation state. Penicillamine is being studied as a model for glutathione since both have sulfhydryl groups which are involved in redox and coordination chemistry. The electrochemistry in DMSO of penicillamine, its carboxylic ester, and their VO 2 + complexes are discussed in this paper

Preparation of silica nanocomposite anion-exchange membranes with low vanadium-ion crossover for vanadium redox flow batteries

International Nuclear Information System (INIS)

Leung, P.K.; Xu, Q.; Zhao, T.S.; Zeng, L.; Zhang, C.

2013-01-01

Highlights: • The permeability of vanadium ions through the silica nanocomposite AEM (SNAEM) is ten times lower than that for Nafion 115. • The rates of self-discharge and capacity fading of the VRFB are substantially reduced with the use of the SNAEM. • The Coulombic and energy efficiencies are as high as 92% and 73%, respectively, at 40 mA cm −2 . -- Abstract: Crossover of vanadium ions through the membranes of all-vanadium redox flow batteries (VRFB) is an issue that limits the performance of this type of flow battery. This paper reports on the preparation of a sol–gel derived silica nanocomposite anion exchange membrane (AEM) for VRFBs. The EDS and FT-IR characterizations confirm the presence and the uniformity of the silica nanoparticles formed in the membrane via an in situ sol–gel process. The properties of the obtained membrane, including the ion-exchange capacity, the area resistance, and the water uptake, are evaluated and compared to the pristine AEM and the Nafion cation exchange membrane (CEM). The experimental results show that the permeability of the vanadium ions through the silica nanocomposite AEM is about 20% lower than that of the pristine AEM, and one order of magnitude lower than that of the Nafion CEM. As a result, the rates of self-discharge and the capacity fading of the VRFB are substantially reduced. The Coulombic and energy efficiencies at a current density of 40 mA cm −2 are, respectively, as high as 92% and 73%

77 FR 51825 - Ferrovanadium and Nitrided Vanadium From Russia

Science.gov (United States)

2012-08-27

... Nitrided Vanadium From Russia Determination On the basis of the record \\1\\ developed in the subject five... order on ferrovanadium and nitrided vanadium from Russia would not be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably foreseeable time. \\1...

Electrochemical Oscillation of Vanadium Ions in Anolyte

Directory of Open Access Journals (Sweden)

Hao Peng

2017-08-01

Full Text Available Periodic electrochemical oscillation of the anolyte was reported for the first time in a simulated charging process of the vanadium redox flow batteries. The electrochemical oscillation could be explained in terms of the competition between the growth and the chemical dissolution of V2O5 film. Also, the oscillation phenomenon was possible to regular extra power consumption. The results of this paper might enable new methods to improve the charge efficiency and energy saving for vanadium redox flow batteries.

Temperature dependence of the damage microstructures in neutron-irradiated vanadium

Energy Technology Data Exchange (ETDEWEB)

Horton, L.L.; Farrell, K.

1983-01-01

Vanadium and vanadium with boron carbide additions (V-B/sub 4/C) were irradiated to approx. 1 dpa in the Oak Ridge Research Reactor at controlled temperatures ranging from 455 to 925 K. The V-B/sub 4/C alloy was enriched in /sup 10/B, which produced approx. 3900 at. ppM helium. In the vanadium specimens, the dislocation microstructures varied from clusters of small (< 50 nm diam) dislocation loops (455 to 625 K) to larger, homogeneously distributed loops at higher temperatures. Their Burgers vectors were a/2<111>. The V-B/sub 4/C specimens contained only tangled dislocation segments. Cavities were observed in all specimens. The cavity concentration decrease and the average diameter increased with increasing irradiation temperature. At 725 K, the maximum swelling was observed in both the vanadium (0.1%) and V-B/sub 4/C (1.4%). At comparable temperatures the cavities in the V-B/sub 4/C specimens were smaller and more numerous than those in the vanadium specimens. Helium bubbles were found on the grain boundaries in all of the V-B/sub 4/ specimens.

A Disposable Alkaline Phosphatase-Based Biosensor for Vanadium Chronoamperometric Determination

Directory of Open Access Journals (Sweden)

Ana Lorena Alvarado-Gámez

2014-02-01

Full Text Available A chronoamperometric method for vanadium ion determination, based on the inhibition of the enzyme alkaline phosphatase, is reported. Screen-printed carbon electrodes modified with gold nanoparticles were used as transducers for the immobilization of the enzyme. The enzymatic activity over 4-nitrophenyl phosphate sodium salt is affected by vanadium ions, which results in a decrease in the chronoamperometric current registered. The developed method has a detection limit of 0.39 ± 0.06 µM, a repeatability of 7.7% (n = 4 and a reproducibility of 8% (n = 3. A study of the possible interferences shows that the presence of Mo(VI, Cr(III, Ca(II and W(VI, may affect vanadium determination at concentration higher than 1.0 mM. The method was successfully applied to the determination of vanadium in spiked tap water.

Hydrogen release from vanadium alloy V-4Cr-4Ti

International Nuclear Information System (INIS)

Klepikov, A.Kh; Kulsartov, T.V.; Chikhray, E.V.; Romanenko, O.G.; Tazhibaeva, I.L.; Shestakov, V.P.

1999-01-01

The experiments on hydrogen loading of vanadium alloy with the following thermodesorption spectroscopy (TDS) measurements were carried out with the sample of the V-4Cr-4Ti vanadium alloy (Russia production). Hydrogen solubility was calculated from experimental TDS curves, obtained after equilibrium loading of the sample at the temperatures 673, 773, 873, 973, and 1073 K. The range of loading pressures was 10-100 Pa. The experiments carried out had an objective to determine the regimes (loading time, temperatures and pressures) for the experiment on in-pile loading of the vanadium alloy. (author)

Processing, characterization, and bactericidal activity of undoped and silver-doped vanadium oxides

Energy Technology Data Exchange (ETDEWEB)

Tousley, M.E.; Wren, A.W.; Towler, M.R. [Inamori School of Engineering, Alfred University, Alfred, NY 14803 (United States); Mellott, N.P., E-mail: mellott@alfred.edu [Inamori School of Engineering, Alfred University, Alfred, NY 14803 (United States)

2012-12-14

Vanadium oxide (V) and silver-doped vanadium oxide (Ag-V) powders were prepared via sol-gel processing. Structural evolution and bactericidal activity was examined as a function of temperature ranging from 250, 350, 450 and 550 Degree-Sign C. Powders were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy. Results from all techniques showed vanadium pentoxide (V{sub 2}O{sub 5}) is the predominant phase regardless of heat treatment temperature or the addition of silver (Ag). XRD analysis suggests Ag is present as AgCl in samples heat treated to 250, 350, and 450 Degree-Sign C and as AgV{sub 6}O{sub 15} at 550 Degree-Sign C. Bactericidal activity was evaluated against Escherichia coli using the agar disk diffusion method considering both Ag-V and undoped, V powders. While the addition of Ag significantly increased bactericidal properties, the specific Ag valency, or crystal structure and morphology formed at higher temperatures, had little effect on functionality. -- Highlights: Black-Right-Pointing-Pointer Vanadium and silver-doped vanadium oxide powders were prepared via sol-gel. Black-Right-Pointing-Pointer Powders were characterized using advanced, complementary structural techniques. Black-Right-Pointing-Pointer Bactericidal activity was evaluated against E. coli. Black-Right-Pointing-Pointer Both vanadium and silver doped vanadium oxide show bactericidal activity.

Intercalation compounds of vanadium(5) phosphates with glycerol

International Nuclear Information System (INIS)

Yakovleva, T.N.; Vykhodtseva, K.I.; Tarasova, D.V.; Soderzhinova, M.M.

1997-01-01

Interaction products of glycerol aqueous solutions with vanadium(5) phosphates were investigated by the methods of ESR, X-ray phase and thermal analyses. It is shown that glycerol molecules enter the interlayer space of VOPO 4 · 2H 2 O lattice with formation of disordered intercalated compounds with glycerol on the basis of partially reduced vanadium phosphate form when using α-VOPO 4 . 16 refs., 4 figs., 1 tab

Vanadium, rubidium and potassium in Octopus vulgaris (Mollusca: Cephalopoda

Directory of Open Access Journals (Sweden)

Sónia Seixas

2005-06-01

Full Text Available The levels of vanadium, rubidium and potassium were determined in Octopus vulgaris caught during commercial fishing activities at three locations (Cascais, Santa Luzia and Viana do Castelo in Portugal in autumn and spring. We determined the concentration of these elements in digestive gland, branchial heart, gills, mantle and arms in males and females. At least five males and five females were assessed for each season/location combination. Elemental concentrations were determined by Particle Induced X-ray Emission (PIXE. Vanadium was detectable only in digestive gland and branchial heart samples. Its concentration was not correlated with total weight, total length or mantle length. There were no differences in concentrations of V, Rb and K between sexes. There were significant differences in vanadium concentrations in branchial hearts in autumn between samples from Viana do Castelo and those from the other two sites. We found a significant positive relationship between the concentration of vanadium and those of potassium and rubidium in branchial hearts. Branchial hearts appear to play an important role in decontamination of V.

The Balance of Titanium and Vanadium in the Blast Furnace with the Use of Sinter Containing a Titanium-Vanadium-Magnetite Concentrate

Directory of Open Access Journals (Sweden)

Budzik, R.

2007-01-01

Full Text Available The investigation concerned the use of sinter containing a titanium-vanadium-magnetite concentrate for the production of pig iron. Sinter containing 0,46 to 0,51 % TiO2 and 0,056 to 0,060 % vanadium was used for pig iron production in the blast furnace. Introducing 200 kg of this concentrate to the1 Mg sinter mix did not cause any deterioration of sinter quality.

Preparation Of Pure Vanadium Pentoxide From Red Cake

International Nuclear Information System (INIS)

ZAREH, M.M.; EL-HAZEK, M.N; BU ZAID, A.H.M; MOHAMED, H.S.

2010-01-01

The red cake, extracted from petroleum ash by acid leaching, contains some impurities such as iron, nickel, zinc, Cr and Cu. For purification the red cake, vanadium in the red cake was taken into solution by treating the red cake with soda ash solution at 90 o C, S /L 1/10 and leaching time of 6 h. The obtained leaching efficiency of vanadium reached 99 %. The solution was clarified by filtration and slurred with solid ammonium sulphate (50g/l) and ammonium chloride (50 g/l). The pH of the slurry was kept at 8-9 by adding ammonium hydroxide. Ammonium metavanadate was crystallized from the slurry at room temperature and during the crystallization step, the slurry was kept under mild agitation. The reaction between the sodium vanadate and ammonium sulphate led to the formation of ammonium metavanadate (AMV) 98.35 % (atomic adsorption techniques). The AMV crystals were separated from the residual liquor by filtration, washed with 5% ammonium chloride solution then dried at 100 o C. Over 98.35 % of the vanadium contained in the red cake was recovered by this way as AMV. Thermal decomposition of AMV at 350 o C 1 h yielded 99.32 % pure vanadium pentoxide.

Magnetic and luminescent properties of vanadium-doped ZnSe crystals

Energy Technology Data Exchange (ETDEWEB)

Radevici, Ivan, E-mail: ivarad@utu.fi [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., MD-2009 Chisinau (Moldova, Republic of); Nedeoglo, Natalia; Sushkevich, Konstantin [Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., MD-2009 Chisinau (Moldova, Republic of); Huhtinen, Hannu [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Nedeoglo, Dmitrii [Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., MD-2009 Chisinau (Moldova, Republic of); Paturi, Petriina [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)

2016-12-15

Magnetic and photoluminescence properties of vanadium-doped ZnSe crystals with impurity concentrations varied by changing the V amount in the source material from 0.03 to 0.30 at% are studied in 5–300 K temperature range. Investigation of magnetic properties shows that the studied concentrations of vanadium impurity that should not disturb crystal lattice are insignificant for observing ferromagnetic behaviour even at low temperatures. The contribution of V impurity to edge emission and its influence on infra-red emission are discussed. Similarities of magnetic and luminescent properties induced by vanadium and other transition metal impurities are discussed.

Interaction of titanium and vanadium with carbon dioxide under heating

International Nuclear Information System (INIS)

Vlasyuk, R.Z.; Kurovskij, V.Ya.; Lyapunov, V.P.; Radomysel'skij, I.D.

1986-01-01

The methods of gravitmetric and X-ray phase analysis as well as analysis of composition of gases in the heating chamber have been used to investigate the mechanism of titanium and vanadium interaction with carbon dioxide in the 300-1000 deg C temperature range. The analogy of mechanisms of the interaction of titanium and vanadium with carbon dioxide in oxides production on the metal surface with subsequent carbidizing treatment at temperatures above 800 deg C is shown. Temperature limits of material operation on the base of titanium or vanadium in carbon dioxide must not exceed 400 or 600 deg C, respectively

Quantitative LIBS analysis of vanadium in samples of hexagonal mesoporous silica catalysts.

Science.gov (United States)

Pouzar, Miloslav; Kratochvíl, Tomás; Capek, Libor; Smoláková, Lucie; Cernohorský, Tomás; Krejcová, Anna; Hromádko, Ludek

2011-02-15

The method for the analysis of vanadium in hexagonal mesoporous silica (V-HMS) catalysts using Laser Induced Breakdown Spectrometry (LIBS) was suggested. Commercially available LIBS spectrometer was calibrated with the aid of authentic V-HMS samples previously analyzed by ICP OES after microwave digestion. Deposition of the sample on the surface of adhesive tape was adopted as a sample preparation method. Strong matrix effect connected with the catalyst preparation technique (1st vanadium added in the process of HMS synthesis, 2nd already synthesised silica matrix was impregnated by vanadium) was observed. The concentration range of V in the set of nine calibration standards was 1.3-4.5% (w/w). Limit of detection was 0.13% (w/w) and it was calculated as a triple standard deviation from five replicated determinations of vanadium in the real sample with a very low vanadium concentration. Comparable results of LIBS and ED XRF were obtained if the same set of standards was used for calibration of both methods and vanadium was measured in the same type of real samples. LIBS calibration constructed using V-HMS-impregnated samples failed for measuring of V-HMS-synthesized samples. LIBS measurements seem to be strongly influenced with different chemical forms of vanadium in impregnated and synthesised samples. The combination of LIBS and ED XRF is able to provide new information about measured samples (in our case for example about procedure of catalyst preparation). Copyright © 2010 Elsevier B.V. All rights reserved.

Vanadium in organic fossils as determined by nuclear-physical methods of analysis

International Nuclear Information System (INIS)

Nadirov, N.N.; Solodukhin, V.P.

1998-01-01

Results are presented of several year investigation to study possibilities of the NPMA for the determination of vanadium in organic fossils and applications of these methods to scientific and practical tasks. For these purposes, various versions of activation analysis (AA), X-ray fluorescence analysis (XRFA), electron spin resonance (ESR) spectroscopy and atomic emission with inductively coupled plasma spectroscopy (AES-ICP). Advantages and pitfalls of individual methods are discussed. The techniques developed can be used for estimation and calculation of stocks of vanadium in organic fossils at the territories of Kazakstan, Tatarstan and along the Volga-river. Analysis results helped in discovering new, industrially important deposits of this valuable metal. Quantitative determination of vanadium was carried out at different stages of technological processes of its extraction from high-viscous oils and oil-bitumen rocks. Results of analyses allowed to reveal the most effective versions of technologies of demetallization of these fossils. Content of vanadium was also studied in different locations of high-viscous oil deposits being explored by the method of inside-stratum burning. Results of analyses showed that the concentration of vanadium in oil decreases considerably with increasing temperature, that is, a considerable part of vanadium (up to 60 percent) may be lost irretrievably. Thus, for the exploration of these deposits a method of vapor-thermal influence onto the stratum was recommended, by using of which the loss of vanadium is insignificant

Development of vanadium base alloys for fusion first-wall/blanket applications

International Nuclear Information System (INIS)

Smith, D.L.; Chung, H.M.; Loomis, B.A.; Matsui, H.; Votinov, S.; VanWitzenburg, W.

1994-01-01

Vanadium alloys have been identified as a leading candidate material for fusion first-wall/blanket applications. Certain vanadium alloys exhibit favorable safety and environmental characteristics, good fabricability, high temperature and heat load capability, good compatibility with liquid metals and resistance to irradiation damage effects. The current focus is on vanadium alloys with (3-5)% Cr and (3-5)% Ti with a V-4Cr-4Ti alloy as the leading candidate. Preliminary results indicate that the crack-growth rates of certain alloys are not highly sensitive to irradiation. Results from the Dynamic Helium Charging Experiment (DHCE) which simulates fusion relevant helium/dpa ratios are similar to results from neutron irradiated material. This paper presents an overview of the recent results on the development of vanadium alloys for fusion first wall/blanket applications

Neurotoxic profiles of vanadium when administered at the onset of ...

African Journals Online (AJOL)

Pups exposed to vanadium showed reduced upper body strength which was protected by administration of vit E. Routine histology with Haematoxylin and Eosin revealed increased necrotic neurons of the medulla in vanadium exposed rats. Cresyl Violet stain showed depletion of the external granular layer of the ...

Annealing of radiation-induced defects in vanadium and vanadium-titanium alloys

International Nuclear Information System (INIS)

Leguey, T.

1996-01-01

The annealing of defects induced by electron irradiation up to a dose of 6.10 21 m -2 at T<293 K has been investigated in single-crystals of pure vanadium and in vanadium-titanium alloys with compositions 0.3, 1 and 5 at.% Ti using positron annihilation spectroscopy. The recovery of the positron annihilation parameters in V single-crystals indicates that the defect annealing takes place in the temperature range 410-470 K without formation of microvoids for the present irradiation conditions. For the alloys the recovery onset is shifted to 460 K, the width of the annealing stage is gradually broadened with increasing Ti content, and microvoids are formed for annealing temperatures at the end of the recovery stage. The results show that the vacancy release from vacancy-interstitial impurity pairs and subsequent recombination with interstitial loops is the mechanism of the recovery in pure V. For V-Ti alloys, vacancy-Ti-interstitial impurity complexes and vacancy-Ti pairs appear to be the defects responsible for the positron trapping. The broadening of the recovery stage with increasing Ti content indicates that solute Ti is a very effective trap for vacancies in V. (orig.)

Swelling and tensile properties of neutron-irradiated vanadium alloys

International Nuclear Information System (INIS)

Loomis, B.A.; Smith, D.L.

1990-07-01

Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600 degree C to neutron fluences ranging from 0.3 to 1.9 x 10 27 neutrons/m 2 (17 to 114 atom displacements per atom [dpa])

Effect of organic additives on positive electrolyte for vanadium redox battery

International Nuclear Information System (INIS)

Li Sha; Huang Kelong; Liu Suqin; Fang Dong; Wu Xiongwei; Lu Dan; Wu Tao

2011-01-01

Highlights: → Four organics as electrolyte additives of vanadium redox battery. → Changes are examined in the electrochemical properties of vanadium redox battery. → D-sorbitol is a suitable additive to the electrolyte for the vanadium redox battery. → The mechanism of improvement is discussed in detail. - Abstract: Fructose, mannitol, glucose, D-sorbitol are explored as additives in electrolyte for vanadium redox battery (VRB), respectively. The effects of additives on electrolyte are studied by cyclic voltammetry (CV), charge-discharge technique, electrochemical impedance spectroscopy (EIS) and Raman spectroscopy. The results indicate that the vanadium redox cell using the electrolyte with the additive of D-sorbitol exhibits the best electrochemical performance (the energy efficiency 81.8%). The EIS results indicate that the electrochemical activity of the electrolyte is improved by adding D-sorbitol, which can be interpreted as the increase of available (-OH) groups providing active sites for electron transfer. The Raman spectra show that VO 2+ ions take part in forming a complex with the D-sorbitol, which not only improve solubility of V(V) electrolyte, but also provide more activity sites for the V(IV)/V(V) redox reaction.

Effect of organic additives on positive electrolyte for vanadium redox battery

Energy Technology Data Exchange (ETDEWEB)

Li Sha [Department of Functional Materials and Chemistry, School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Huang Kelong, E-mail: lisha_csu@163.com [Department of Functional Materials and Chemistry, School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Liu Suqin; Fang Dong; Wu Xiongwei; Lu Dan; Wu Tao [Department of Functional Materials and Chemistry, School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

2011-06-30

Highlights: > Four organics as electrolyte additives of vanadium redox battery. > Changes are examined in the electrochemical properties of vanadium redox battery. > D-sorbitol is a suitable additive to the electrolyte for the vanadium redox battery. > The mechanism of improvement is discussed in detail. - Abstract: Fructose, mannitol, glucose, D-sorbitol are explored as additives in electrolyte for vanadium redox battery (VRB), respectively. The effects of additives on electrolyte are studied by cyclic voltammetry (CV), charge-discharge technique, electrochemical impedance spectroscopy (EIS) and Raman spectroscopy. The results indicate that the vanadium redox cell using the electrolyte with the additive of D-sorbitol exhibits the best electrochemical performance (the energy efficiency 81.8%). The EIS results indicate that the electrochemical activity of the electrolyte is improved by adding D-sorbitol, which can be interpreted as the increase of available (-OH) groups providing active sites for electron transfer. The Raman spectra show that VO{sup 2+} ions take part in forming a complex with the D-sorbitol, which not only improve solubility of V(V) electrolyte, but also provide more activity sites for the V(IV)/V(V) redox reaction.

Hydrogen Production by Steam Reforming of Natural Gas Over Vanadium-Nickel-Alumina Catalysts.

Science.gov (United States)

Yoo, Jaekyeong; Park, Seungwon; Song, Ji Hwan; Song, In Kyu

2018-09-01

A series of vanadium-nickel-alumina (xVNA) catalysts were prepared by a single-step sol-gel method with a variation of vanadium content (x, wt%) for use in the hydrogen production by steam reforming of natural gas. The effect of vanadium content on the physicochemical properties and catalytic activities of xVNA catalysts in the steam reforming of natural gas was investigated. It was found that natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to vanadium content. It was also revealed that natural gas conversion and hydrogen yield increased with decreasing nickel crystallite size.

Effect of vanadium contamination on the framework and micropore structure of ultra stable Y-zeolite.

Science.gov (United States)

Etim, U J; Xu, B; Ullah, Rooh; Yan, Z

2016-02-01

Y-zeolites are the main component of fluid catalytic cracking (FCC) catalyst for conversion of crude petroleum to products of high demand including transportation fuel. We investigated effects of vanadium which is present as one of the impurities in FCC feedstock on the framework and micropore structure of ultra-stable (US) Y-zeolite. The zeolite samples were prepared and characterized using standard techniques including: (1) X-ray diffraction, (2) N2 adsorption employing non local density functional theory method, NLDFT, (3) Transmittance and Pyridine FTIR, (4) Transmittance electron microscopy (TEM), and (5) (27)Al and (29)Si MAS-NMR. Results revealed that in the presence of steam, vanadium caused excessive evolution of non inter-crystalline mesopores and structural damage. The evolved mesopore size averaged about 25.0nm at 0.5wt.% vanadium loading, far larger than mesopore size in zeolitic materials with improved hydrothermal stability and performance for FCC catalyst. A mechanism of mesopore formation based on accelerated dealumination has been proposed and discussed. Vanadium immobilization experiments conducted to mitigate vanadium migration into the framework clearly showed vanadium is mobile at reaction conditions. From the results, interaction of vanadium with the passivator limits and decreases mobility and activity of vanadium into inner cavities of the zeolite capable of causing huge structure breakdown and acid sites destruction. This study therefore deepens insight into the causes of alteration in activity and selectivity of vanadium contaminated catalyst and hints on a possible mechanism of passivation in vanadium passivated FCC catalyst. Copyright © 2015 Elsevier Inc. All rights reserved.

Biodiesel production over copper vanadium phosphate

International Nuclear Information System (INIS)

Chen, Lei; Yin, Ping; Liu, Xiguang; Yang, Lixia; Yu, Zhongxi; Guo, Xin; Xin, Xinquan

2011-01-01

In the present study, copper vanadium phosphate (CuVOP) with three-dimensional network structure was synthesized by hydrothermal method, and was characterized by Infrared spectrum (IR), elemental analysis (EA), EDXRF (energy dispersive X ray fluorescence) etc. Moreover, soybean oil was used as feedstock for producing biodiesel, and biodiesel was produced by CuVOP-catalyzed transesterification process. Response surface methodology was employed to statistically evaluate and optimize the conditions for the maximum conversion to biodiesel, and the effects of amount of catalyst, ratio of methanol to oil, reaction time and reaction temperature were investigated by the 2 4 full-factorial central composite design. The maximum conversion is obtained at amount of catalyst of 1.5%, methanol/oil molar ratio of 6.75, reaction temperature of 65 o C and reaction time of 5 h. Copper vanadium phosphate CuVOP resulted very active in the transesterification reaction for biodiesel production. -- Research highlights: → Copper vanadium phosphate CuVOP with three-dimensional network structure was prepared successfully. Moreover, for the transesterification reaction of soybean oil with methanol under atmospheric pressure, CuVOP had higher catalytic activity and the effects of production conditions such as amount of catalysts etc. were analyzed by response surface methodology.

Vanadium-Catalyzed Enantioselective Desymmetrization of meso-Secondary Allylic Alcohols and Homoallylic Alcohols

OpenAIRE

Li, Zhi; Zhang, Wei; Hisashi Yamamoto, H.

2008-01-01

Vanadium-catalyzed epoxidation has extended substrate scope. In addition to various bis-allylic alcohols, bis-homoallylic alcohols can also be desymmetrized using our Vanadium-Bis-hydroxamic acid complexes.

Strategies for enhancing electrochemical activity of carbon-based electrodes for all-vanadium redox flow batteries

International Nuclear Information System (INIS)

Flox, Cristina; Skoumal, Marcel; Rubio-Garcia, Javier; Andreu, Teresa; Morante, Juan Ramón

2013-01-01

Highlights: ► Improved reactions at the positive electrode in all-vanadium redox flow batteries. ► Graphene-derived and PAN-modified electrodes have been successfully prepared. ► Modification with bimetallic CuPt 3 nanocubes yielded the best catalytic behavior. ► N and O-containing groups enhances the vanadium flow battery performance. - Abstract: Two strategies for improving the electroactivity towards VO 2+ /VO 2 + redox pair, the limiting process in all-vanadium redox flow batteries (VFBs), were presented. CuPt 3 nanoparticles supported onto graphene substrate and nitrogen and oxygen polyacrylonitrile (PAN)-functionalized electrodes materials have been evaluated. The morphology, composition, electrochemical properties of all electrodes prepared was characterized with field emission-scanning electrode microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and cell charge–discharge test. The presence of the CuPt 3 nanocubes and nitrogen and oxygen functionalities enhance the electrocatalytic activity of the electrodes materials accelerating the oxygen and electron transfer processes. The battery performance was also evaluated using PAN-functionalized electrodes exhibiting a high of energy efficiency of 84% (at current density 20 mA cm −2 ) up to 30th cycle, indicating a promising alternative for improving the VFB

Vanadium determination in raw materials and products of aluminium production using pulse polarography

International Nuclear Information System (INIS)

Grigor'eva, M.F.; Bal'de, I.; Markovich, I.A.

1992-01-01

Possibility of using differential pulse polarography (DPP) for determination of vanadium in raw materials and products of aluminium production was studied. Ammonium-cheoride buffer solution with pH 9-10, aqueous solution of mixture of sodium carbonate and borax (1:3) and rhodanide-acefic acid solutions (1:1) were tested as a background. Current-voltage curves of vanadium reduction were plotted and peak potentials on DPP were determined against the background of chosen electrolytes. Effect of parameters, providing the maximal height of DPP peak, on the height of measured signal, was studied. Rhodanide background was chosen for polarographic determination of vanadium, because the detection limit of vanadium was the lowest against this background. Pulse polarography enafles to determine vanadium in products of aluminium production in amounts from 1x10 -4 to 0.01 % and more

Concentration of vanadium in crude oil and water using inductively-coupled plasma spectrometry

International Nuclear Information System (INIS)

Amin, Y.M.; Hassan, M.A.; Junkin, K.; Mahat, R.H.; Raphie, B.

1991-01-01

Vanadium is a trace element that is usually associated to crude oil and its products. In this study the concentration of vanadium in a few samples of local crude oil, sea and river water were determined using inductively-coupled plasma spectrometry (ICP). It is hoped that the concentration of vanadium in water can be used to indicate the possible extent of oil contamination

A nuclear on-line sensor for continuous control of vanadium content in oil pipelines

International Nuclear Information System (INIS)

Rizk, R.A.M.

1989-01-01

Trace amounts of vanadium in crude oil and in heavy distillate fuels are very harmful due to their corrosive action. Thus the necessity arises for continuous control of the vanadium content in oil pipelines. Moreover, the development of a nuclear on-line sensor that can continuously analyze the vanadium content in oil pipelines may lead to a better control of processing operations. In this paper a feasibility study for on-line analysis of vanadium in crude oil by means of neutron activation analysis is presented. (author)

The Influence of Vanadium on Ferrite and Bainite Formation in a Medium Carbon Steel

Science.gov (United States)

Sourmail, T.; Garcia-Mateo, C.; Caballero, F. G.; Cazottes, S.; Epicier, T.; Danoix, F.; Milbourn, D.

2017-09-01

The influence of vanadium additions on transformation kinetics has been investigated in a medium carbon forging steel. Using dilatometry to track transformation during continuous cooling or isothermal transformation, the impact of vanadium on both ferrite-pearlite and bainite has been quantified. Transmission electron microscopy and atom probe tomography have been used to establish whether vanadium was present in solid solution, or as clusters and precipitates. The results show that vanadium in solid solution has a pronounced retarding influence on ferrite-pearlite formation and that, unlike in the case of niobium, this effect can be exploited even during relatively slow cooling. The influence on bainite transformation was found to depend on temperature; an explanation in terms of the effect of vanadium on heterogeneous nucleation is tentatively proposed.

Study on wear resistance of vanadium alloying compacted/vermicular graphite cast iron

International Nuclear Information System (INIS)

Park, Yoon Woo

1987-01-01

Wear resistance of the Compacted/Vermicular graphite cast irons was studied by changing the vanadium content in the cast irons. The results obtained in this work are summarized as follows. 1. When the same amount of vanadium was added to the flake graphite cast iron, spheroidal graphitecast iron and Compacted/Vermicular graphite cast iron, spheroidal graphite cast iron and Compacted/Vermicular graphite cast iron wear resistance decreased in following sequence, that is, flake graphite cast iron> spheroidal graphite cast iron>Compacted/Vermicular graphite cast iron. 2. Addition of vanadium to the Compacted/Vermicular cast iron leaded to a remarkable increase in hardness because it made the amount of pearlite in matrix increase. 3. Addition of vanadium to the compacted/Vermicular graphite cast iron significantly enhanced wear resistance and the maximum resistance was achieved at about 0.36% vanadium. 4. The maximum amount of wear apppeared at sliding speed of about 1.4m/sec and wear mode was considered to be oxidation abrasion from the observation of wear tracks. (Author)

Electrochemical behaviour of a vanadium anode in phosphoric acid and phosphate solutions

International Nuclear Information System (INIS)

Alonzo, V.; Darchen, A.; Fur, E. Le; Pivan, J.Y.

2006-01-01

Anodic polarisation of a vanadium electrode has been studied in H 3 PO 4 solutions and some phosphate solutions: LiH 2 PO 4 , NaH 2 PO 4 , KH 2 PO 4 and NH 4 H 2 PO 4 . The anodic behaviour of a vanadium electrode showed similarities in weak concentrated H 3 PO 4 , in LiH 2 PO 4 and NaH 2 PO 4 solutions: the polarisation curve exhibited a current peak followed by current oscillations and then a current plateau. Concentrated H 3 PO 4 , 1 M KH 2 PO 4 and NH 4 H 2 PO 4 solutions involved vanadium passivation with a very slight current density plateau. Yellow compound identified to VOPO 4 .2H 2 O was obtained after controlled potential oxidation of vanadium in 5-10 M H 3 PO 4 . Green products were obtained in 1 M phosphate solutions and in 1-3 M H 3 PO 4 on vanadium anode after controlled potential electrolysis. All these vanadophosphate compounds contained the monovalent cation which was present in the solution

Adsorption Behavior of Vanadium in Presence of alumina with Emphasize on Triple Layer Model Simulation

International Nuclear Information System (INIS)

El-Sayed, A.A.

2006-01-01

Adsorption behavior of vanadium in alumina colloidal solution as simulation for soil-water and/or sediment - water system was investigated. factors affecting this behavior including Ph, humic acid and alumina concentrations were studied. Three stages of vanadium adsorption on alumina were approved due to Ph changes. The first is increasing adsorption with increasing Ph, in the range 1-3. the second is decreasing adsorption with increasing Ph in the range 6-10. the third is constant adsorption at 100% adsorption in Ph range 3-8 at 10 g/l concentration of alumina. However, at 0.2 g/l, the maximum adsorption of vanadium became less than 100%.The effect of humic acid on the adsorption behavior of vanadium (V) was studied and compared with that of vanadium (IV) . Adsorption behaviors were studied at concentration 4.1 E-4 M for vanadium at 0.1 M ionic strength. Triple layer model was used for simulation of vanadium adsorption behavior in presence of alumina under the same working conditions. the results showed good validation and verification to the data practically found. speciation of vanadium in both homogenous and heterogeneous systems was also studied theoretically so as to verify the most abundant elemental species and its impact on the environment

A comparative assessment of the acute inhalation toxicity of vanadium compounds.

Science.gov (United States)

Rajendran, N; Seagrave, J C; Plunkett, L M; MacGregor, J A

2016-11-01

Vanadium compounds have become important in industrial processes, resulting in workplace exposure potential and are present in ambient air as a result of fossil fuel combustion. A series of acute nose-only inhalation toxicity studies was conducted in both rats and mice in order to obtain comparative data on the acute toxicity potential of compounds used commercially. V 2 O 3 , V 2 O 4 , and V 2 O 5 , which have different oxidation states (+3, +4, +5, respectively), were delivered as micronized powders; the highly water-soluble and hygroscopic VOSO 4 (+4) could not be micronized and was instead delivered as a liquid aerosol from an aqueous solution. V 2 O 5 was the most acutely toxic micronized powder in both species. Despite its lower overall percentage vanadium content, a liquid aerosol of VOSO 4 was more toxic than the V 2 O 5 particles in mice, but not in rats. These data suggest that an interaction of characteristics, i.e., bioavailability, solubility and oxidation state, as well as species sensitivity, likely affect the toxicity potential of vanadium compounds. Based on clinical observations and gross necropsy findings, the lung appeared to be the target organ for all compounds. The level of hazard posed will depend on the specific chemical form of the vanadium. Future work to define the inhalation toxicity potential of vanadium compounds of various oxidation states after repeated exposures will be important in understanding how the physico-chemical and biological characteristics of specific vanadium compounds interact to affect toxicity potential and the potential risks posed to human health.

Novel hybrid materials based on the vanadium oxide nanobelts

Energy Technology Data Exchange (ETDEWEB)

Zabrodina, G.S., E-mail: kudgs@mail.ru [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation); Makarov, S.G.; Kremlev, K.V. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation); Yunin, P.A.; Gusev, S.A. [Institute for Physics of Microstructures Russian Academy of Sciences, Nizhny Novgorod 603087 (Russian Federation); Kaverin, B.S.; Kaverina, L.B. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Ketkov, S.Yu. [G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, Nizhny Novgorod 603950 (Russian Federation)

2016-04-15

Graphical abstract: - Highlights: • Flat and curved vanadium oxide nanobelts have been synthesized. • Hybrid material was prepared via decoration of flexible nanobelts with zinc phthalocyanine. • Investigations of the thermal stability, morphologies and structures were carried out. - Abstract: Novel hybrid materials based on zinc phthalocyanine and nanostructured vanadium oxides have attracted extensive attention for the development of academic research and innovative industrial applications such as flexible electronics, optical sensors and heterogeneous catalysts. Vanadium oxides nanobelts were synthesized via a hydrothermal treatment V{sub 2}O{sub 5}·nH{sub 2}O gel with surfactants (TBAB, CTAB) used as structure-directing agents, where CTAB – cetyltrimethylammonium bromide, TBAB – tetrabutylammonium bromide. Hybrid materials were prepared decoration of (CTA){sub 0.33}V{sub 2}O{sub 5} flexible nanobelts with cationic zinc phthalocyanine by the ion-exchange route. Investigations of the thermal stability, morphologies and structures of the (CTA){sub 0.33}V{sub 2}O{sub 5}, (TBA){sub 0.16}V{sub 2}O{sub 5} nanobelts and zinc phthalocyanine exchange product were carried out. The hybrid materials based on the nanostructured vanadium oxide and zinc phthalocyanine were tested as photocatalysts for oxidation of citronellol and 2-mercaptoethanol by dioxygen.

Effect of neutron irradiation on vanadium alloys

International Nuclear Information System (INIS)

Braski, D.N.

1986-01-01

Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600 0 C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520 0 C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys

Effect of neutron irradiation on vanadium alloys

Energy Technology Data Exchange (ETDEWEB)

Braski, D.N.

1986-01-01

Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600/sup 0/C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520/sup 0/C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys.

Determination of vanadium in Syrian commercial and raffinate phosphoric acid

International Nuclear Information System (INIS)

Al-Merey, R.

2002-04-01

This study presents two methods for vanadium determination in Syrian commercial phosphoric acid. The vanadium (V) in the oxidized commercial phosphoric acid by ammonium persulfate solution is extracted from 5-M hydrochloride acid medium using N-benzoyl-N-phenyl hydroxyl amine (BPHA) in chloroform as an extracting solution. The first method, the extract vanadium as VOL 2 Cl is changed to V 2 O 3 L 4 complex by the addition of benzimidazole in 1-butanol to the violet organic layer. The absorbance is then measured at 440 nm (the molar absorptivity was found to be 3865 M -1 cm -1 ), where Beer law is applicable up to 36-μg ml -1 . the accuracy, precision and detection limit were found to be 3.7%, 77 ppb and 37 ppb, respectively. the second method, the organic layer is heated to evaporate chloroform, the residue is digested using 20% ammonium persulfate and 2-M sulfuric acid solutions. The vanadium concentration is measured spectrophotometrically by oxidizing gallic acid with persulfate (S 2 O 8 2- ) anion in phosphoric acid medium, where the vanadium (V) acts as a catalyst in the oxidation reaction. This method has a high sensitivity (∼10 -12 ) with accuracy and precision 5% and 0.621 ppb, respectively. Also Beer law at λ m ax=415 nm (ε=∼2 x 10 6 M -1 ) is applicable in the range 2.58-33.3 ppb. (author)

Liquid structure of vanadium tetrachloride from neutron diffraction study

International Nuclear Information System (INIS)

Gopala Rao, R.V.; Satpathy, B.M.

1982-01-01

Assuming the separation of the intermolecular scattering function into the radial and angular parts and using Egelstaff et al's orientational model for tetrachlorides, the structure of liquid vanadium tetrachloride has been studied. It has been observed that such a separation is approximate for this liquid and the introduction of a third correction term is required to account for the molecular structure function. The chlorine-chlorine partial structure and effective angle-averaged intermolecular chlorine-chlorine potential in the liquid has been evaluated. Without taking the third correction term, introduced to generate theoretically the molecular structure function, the centre structure function has been obtained in an approximate way from the experimentally observed molecular structure function and from it the centre radial distribution function, centre direct correlation function and the angle-averaged vanadium-vanadium effective potential has been evaluated. (author)

Investigation on the fates of vanadium and nickel during co-gasification of petroleum coke with biomass.

Science.gov (United States)

Li, Jiazhou; Wang, Xiaoyu; Wang, Bing; Zhao, Jiantao; Fang, Yitian

2018-06-01

This study investigates the volatilization behaviors and mineral transformation of vanadium and nickel during co-gasification of petroleum coke with biomass. Moreover, the evolution of occurrence modes of vanadium and nickel was also determined by the method of sequential chemical extraction. The results show that the volatilities of vanadium and nickel in petroleum coke have a certain level of growth with an increase in the temperature. With the addition of biomass, their volatilities both show an obvious decrease. Organic matter and stable forms are the dominant chemical forms of vanadium and nickel. After gasification, organic-bound vanadium and nickel decompose completely and convert into other chemical forms. The crystalline phases of vanadium trioxide, coulsonite, nickel sulfide, and elemental nickel are clearly present in petroleum coke and biomass gasification ashes. When the addition of biomass reaches 60 wt%, the diffraction peaks of orthovanadate are found while that of vanadium trioxide disappear. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electromigration of hydrogen and deuterium in vanadium and niobium by a resistance method

International Nuclear Information System (INIS)

Peterson, D.T.; Jensen, C.L.

1978-01-01

The electric mobility of hydrogen and deuterium has been measured at 30 0 C in niobium (Cb) and vanadium by a resistance method. The electric mobility was found to be 5.7 x 10 -4 cm 2 /V-s for hydrogen and 2.8 x 10 -4 for deuterium in niobium. In vanadium the electric mobilities were 2.3 x 10 -3 and 1.3 x 10 -3 cm 2 /V-s for hydrogen and deuterium, respectively. The effective charges calculated using reported diffusion coefficients are positive and are slightly greater for deuterium than for hydrogen in both vanadium and niobium. The resistivity increase due to the hydrogen isotopes in vanadium and niobium was also measured. Hydrogen was found to contribute 0.65 μ ohm-cm/at. % and deuterium 0.58 μ ohm-cm/at. % to the resistivity of niobium. In vanadium, the solute resistivities were found to be 0.98 μ ohm-cm/at. % and 0.90 μ ohm-cm/at. % for hydrogen and deuterium, respectively

Nitridation of vanadium by ion beam irradiation

International Nuclear Information System (INIS)

Kiuchi, Masato; Chayahara, Akiyoshi; Kinomura, Atsushi; Ensinger, Wolfgang

1994-01-01

The nitridation of vanadium by ion beam irradiation is studied by the ion implantation method and the dynamic mixing method. The nitrogen ion implantation was carried out into deposited V(110) films. Using both methods, three phases are formed, i.e. α-V, β-V 2 N, and δ-VN. Which phases are formed is related to the implantation dose or the arrival ratio. The orientation of the VN films produced by the dynamic ion beam mixing method is (100) and that of the VN films produced by the ion implantation method is (111). The nitridation of vanadium is also discussed in comparison with that of titanium and chromium. ((orig.))

Enrichment of valuable elements from vanadium slag using superconducting HGMS technology

Energy Technology Data Exchange (ETDEWEB)

He, Sai; Yang, Chang Qiao; Li, Su Qin; Zhang, Chang Quan [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing (China)

2017-03-15

Vanadium slags is a kind of vanadiferous solid waste from steelmaking process. It not only occupies land, pollutes environment, but also leads to waste of resources. Based on the difference of magnetic susceptibility of different particles caused by their chemical and physical properties from vanadium slag, a new technology, superconducting high gradient magnetic separation was investigated for separation and extraction of valuable substances from vanadium slag. The magnetic concentrate was obtained under optimal parameters, i.e., a particle size -200 mesh, a magnetic flux density of 0.8 T, a slurry concentration of 5 g/L, an amount of steel wools of 25 g and a slurry flow velocity of 2 L/min. The content of Fe{sub 2}O{sub 3} in concentrate could be increased from 39.6% to 55.0% and V2O5 from 2.5% to 4.0%, respectively. The recovery rate is up to 42.9%, and the vanadium slag has been effectively reused.

Impurity states of vanadium in cadmium and zinc tellurides

International Nuclear Information System (INIS)

Gnatenko, Yu.P.; Farina, I.A.

1996-01-01

Low-temperature optical (4.5 K) and photoelectrical properties of CdTe and ZnTe crystals doped by vanadium are invetigated. The energies of carrier transition to valence and conduction bands, Mott-Habbard energy for 3d 3 -ion vanadium in both crystals are determined. The resonance of the excited 4 T l ( 4 P)-state of V 2+ -ion with the conduction band of CdTe crystal is found. 8 bibl.; 4 figs

Effects of vanadium on population growth and Na-K-ATPase activity of the brackish water hydroid Cordylophora caspia

Energy Technology Data Exchange (ETDEWEB)

Ringelband, U.; Karbe, L. [Institut fuer Hydrobiologie und Fischereiwissenschaft, Hamburg (Germany)

1996-07-01

Vanadium, a relatively abundant heavy metal, enters the environment naturally through rock weathering. A large fraction of vanadium input is of human origin. The combustion of petroleum- and coal-products, which contain relatively high concentrations of vanadium, is one of the most important sources of the enrichment of vanadium in the environment. As it is used as an alloy, and vanadium rich iron-ores of various origin are used in steel production, the residual slag-stones of the steel industry can contain considerable vanadium concentrations. Wherever slag-stones serve as a cheap and convenient material in riverbank reinforcement, vanadium can leach into the aquatic environment. Vanadium is regarded as an essential trace element for higher animals. Cantley et al. indicated a regulatory function of vanadate in vivo. Although considerable information is available on the toxic effects of vanadium on humans, very little is known about the toxicity of vanadium towards aquatic organisms, especially invertebrates. Bell and Sargent have shown an inhibition of Na-K-ATPase activity in gills of the eel Anguilla anguilla. Holleland and Towle have demonstrated the inhibition of Na-K-ATPase activity in the gills of the shore crab Carcinus maenas. The aim of this study was to determine the toxicity of vanadium towards the brackish water hydroid Cordylophora caspia. Hydroids are known to be particularly sensitive to heavy metals and their asexual reproduction can be used in a well-established population growth test. Furthermore, the effects of vanadium on Na-K-ATPase activity in hydroids were studied in in vivo experiments, wherein the animals were exposed to sublethal concentrations of vanadium. In addition, the inhibition of Na-K-ATPase was measured in vitro, by adding vanadium to a microsomal preparation. 16 refs., 4 figs.

76 FR 78888 - Final Results of Expedited Sunset Review: Ferrovanadium and Nitrided Vanadium From Russia

Science.gov (United States)

2011-12-20

... Sunset Review: Ferrovanadium and Nitrided Vanadium From Russia AGENCY: Import Administration... and nitrided vanadium from the Russian Federation (Russia), pursuant to section 751(c) of the Tariff... vanadium from Russia, pursuant to section 751(c) of the Act. See Initiation of Five-Year (``Sunset...

Fragility–structure–conductivity relations in vanadium tellurite glass

DEFF Research Database (Denmark)

Kjeldsen, Jonas; Yue, Yuanzheng; Rodrigues, Ana Candida Martins

the ability to intercalate lithium-ions, it is a candidate as cathode material. Here, we investigate the correlation between liquid fragility, structure and electronic conductivity in a series of vanadium-tellurite glasses with varying vanadium concentration. We measure dynamic and thermodynamic fragility...... the number of bonding and non-bonding oxygen atoms per network former, while we use IS and ESR to determine the electronic conductivity and the valence states of the system. We correlate the changes in local atomic structures as determined by NMR to the observed changes in macroscopic properties. Since...

Determination of titanium and vanadium in aqueous solutions by potentiometric titration

International Nuclear Information System (INIS)

Sibirkin, A.A.; Elliev, Yu.E.

1996-01-01

Possibility of titanium and vanadium determination at their combined presence by bichromatometric chromometric titration with potentiometric indication of end point is shown. The technique is developed which allows to determine titanium and vanadium with relative standard derivation ±2% in amounts not less than 50 and 100 mg respectively

The determination of vanadium in brines by atomic absorption spectroscopy

Science.gov (United States)

Crump-Wiesner, Hans J.; Feltz, H.R.; Purdy, W.C.

1971-01-01

A standard addition method is described for the determination of vanadium in brines by atomic absorption spectroscopy with a nitrous oxide-acetylene flame. Sample pH is adjusted to 1.0 with concentrated hydrochloric acid and the vanadium is directly extracted with 5% cupferron in methyl isobutyl ketone (MIBK). The ketone layer is then aspirated into the flame and the recorded absorption values are plotted as a function of the concentration of the added metal. As little as 2.5 ??g l-1 of vanadium can be detected under the conditions of the procedure. Tungsten and tin interfere when present in excess of 5 and 10 ??g ml-1, respectively. The concentrations of the two interfering ions normally found in brines are well below interference levels. ?? 1971.

Influence of intoxication with vanadium compounds on the intestinal absorption of calcium in the rat

International Nuclear Information System (INIS)

Witkowska, D.; Oledzka, R.; Pietrzyk, B.

1986-01-01

Calcium is transferred to the plasma after absorption from the gastrointestinal tract and by resorption from the bone. It is recognized that many environmental poisons, e.g. heavy metal, pesticides etc. cause alterations in calcium homeosthasis in human beings and experimental animals. Although vanadium is not considered to be as important a health hazard to man as lead or cadmium it must be nevertheless regarded as a dangerous pollutant. There exists an obvious risk of pollution by and poisoning due to the high vanadium content of crude oil and the industrial use of vanadium as a steel additive. The toxic effects of this element and its compounds in many biological systems have been reviewed in detail but little is known about vanadium influence on calcium metabolism. The present study was undertaken to determine the effect of various treatments with vanadium compounds, containing vanadium as VO 2+ (VOSO 4 ) and VO 3 (NaVO 3 ) ions, exert on calcium transport through the rat duodenum

Vanadium contents in Kazakhstan fossils hydrocarbons by data of nuclear-physical analysis methods

International Nuclear Information System (INIS)

Nadirov, N.K.; Solodukhin, V.P.

1998-01-01

Investigation of nuclear physical methods possibilities of vanadium determination analysis in organic fossils and an application of these methods for solution of scientific and practical tasks are presented. Vanadium contents in high viscous petroleums and petroleum bituminous rock of different deposits of Western Kazakhstan and carbonaceous shales of Dzhangariya are studied. Presented data evidence that organic fossils of numerous deposits of Kazakhstan have industrial interest because of high vanadium concentration in its contents

Characterization of vanadium-doped mesoporous titania and its adsorption of gaseous benzene

Energy Technology Data Exchange (ETDEWEB)

Nguyen-Phan, Thuy-Duong; Song, Myoung Bock; Yun, Hyunran; Kim, Eui Jung; Oh, Eun-Suok [School of Chemical Engineering and Bioengineering, University of Ulsan, Mugeo-dong, Nam-gu, Ulsan 680-749 (Korea, Republic of); Shin, Eun Woo, E-mail: ewshin@mail.ulsan.ac.kr [School of Chemical Engineering and Bioengineering, University of Ulsan, Mugeo-dong, Nam-gu, Ulsan 680-749 (Korea, Republic of)

2011-01-01

A series of vanadium-doped mesoporous titania with different metal contents was synthesized in the study via a sol-gel process with the assistance of a dodecylamine surfactant. The existence of vanadium ions not only suppressed crystallization and sintering but also enhanced the porosity of the mesoporous TiO{sub 2}. Varying the vanadium concentration led to significant changes in the chemical oxidation state of each component. The presence of metal dopants significantly improved the removal efficiency of benzene and the doping the titania with 5 mol% vanadium removed the most benzene, regardless of the adsorption temperature. The adsorption behavior was elucidated by the specific surface area, the interactions between surface hydroxyl groups and the {pi}-electrons of benzene, and the formation of {sigma}-bonding and d-{pi}* back-donation between the adsorbent and organic compounds.

Why Antidiabetic Vanadium Complexes are Not in the Pipeline of "Big Pharma" Drug Research? A Critical Review.

Science.gov (United States)

Scior, Thomas; Guevara-Garcia, Jose Antonio; Do, Quoc-Tuan; Bernard, Philippe; Laufer, Stefan

2016-01-01

Public academic research sites, private institutions as well as small companies have made substantial contributions to the ongoing development of antidiabetic vanadium compounds. But why is this endeavor not echoed by the globally operating pharmaceutical companies, also known as "Big Pharma"? Intriguingly, today's clinical practice is in great need to improve or replace insulin treatment against Diabetes Mellitus (DM). Insulin is the mainstay therapeutically and economically. So, why do those companies develop potential antidiabetic drug candidates without vanadium (vanadium- free)? We gathered information about physicochemical and pharmacological properties of known vanadium-containing antidiabetic compounds from the specialized literature, and converted the data into explanations (arguments, the "pros and cons") about the underpinnings of antidiabetic vanadium. Some discoveries were embedded in chronological order while seminal reviews of the last decade about the Medicinal chemistry of vanadium and its history were also listed for further understanding. In particular, the concepts of so-called "noncomplexed or free" vanadium species (i.e. inorganic oxido-coordinated species) and "biogenic speciation" of antidiabetic vanadium complexes were found critical and subsequently documented in more details to answer the question.

Gastroprotective effect of vanadium in rats - the roles of gastric acid ...

African Journals Online (AJOL)

Stimulation with histamine caused significant increases in gastric output by 187.72%, 57.40% and 78.69% in control, 50 and 200 ppm V respectively and was significantly reduced in the vanadium treated groups. A significant decrease in H+K+ ATPase (proton) pump activities of the vanadium exposed groups compared ...

Effect of vanadium on germination and seedling growth of lettuce (Lactuca sativa L. C. V. salad bowl)

Energy Technology Data Exchange (ETDEWEB)

Lepp, N.W.

1977-01-01

The effect of vanadium, applied as VOSO/sub 4/, on germination and subsequent seedling growth of Lettuce has been studied. No differences in germination were observed at any of the applied vanadium concentrations, when compared to a vanadium-free control. Subsequent seedling growth, however, was significantly inhibited by all vanadium treatments. Reductions in shoot growth, root growth and fresh weight were apparent. Similar, but less dramatic effects were observed when 3 day old seedlings were transferred to vanadium enriched media. 13 references, 2 tables.

Vanadium based materials as electrode materials for high performance supercapacitors

Science.gov (United States)

Yan, Yan; Li, Bing; Guo, Wei; Pang, Huan; Xue, Huaiguo

2016-10-01

As a kind of supercapacitors, pseudocapacitors have attracted wide attention in recent years. The capacitance of the electrochemical capacitors based on pseudocapacitance arises mainly from redox reactions between electrolytes and active materials. These materials usually have several oxidation states for oxidation and reduction. Many research teams have focused on the development of an alternative material for electrochemical capacitors. Many transition metal oxides have been shown to be suitable as electrode materials of electrochemical capacitors. Among them, vanadium based materials are being developed for this purpose. Vanadium based materials are known as one of the best active materials for high power/energy density electrochemical capacitors due to its outstanding specific capacitance and long cycle life, high conductivity and good electrochemical reversibility. There are different kinds of synthetic methods such as sol-gel hydrothermal/solvothermal method, template method, electrospinning method, atomic layer deposition, and electrodeposition method that have been successfully applied to prepare vanadium based electrode materials. In our review, we give an overall summary and evaluation of the recent progress in the research of vanadium based materials for electrochemical capacitors that include synthesis methods, the electrochemical performances of the electrode materials and the devices.

3D-printed conductive static mixers enable all-vanadium redox flow battery using slurry electrodes

Science.gov (United States)

Percin, Korcan; Rommerskirchen, Alexandra; Sengpiel, Robert; Gendel, Youri; Wessling, Matthias

2018-03-01

State-of-the-art all-vanadium redox flow batteries employ porous carbonaceous materials as electrodes. The battery cells possess non-scalable fixed electrodes inserted into a cell stack. In contrast, a conductive particle network dispersed in the electrolyte, known as slurry electrode, may be beneficial for a scalable redox flow battery. In this work, slurry electrodes are successfully introduced to an all-vanadium redox flow battery. Activated carbon and graphite powder particles are dispersed up to 20 wt% in the vanadium electrolyte and charge-discharge behavior is inspected via polarization studies. Graphite powder slurry is superior over activated carbon with a polarization behavior closer to the standard graphite felt electrodes. 3D-printed conductive static mixers introduced to the slurry channel improve the charge transfer via intensified slurry mixing and increased surface area. Consequently, a significant increase in the coulombic efficiency up to 95% and energy efficiency up to 65% is obtained. Our results show that slurry electrodes supported by conductive static mixers can be competitive to state-of-the-art electrodes yielding an additional degree of freedom in battery design. Research into carbon properties (particle size, internal surface area, pore size distribution) tailored to the electrolyte system and optimization of the mixer geometry may yield even better battery properties.

Analysis of soil reference materials for vanadium(+5) species by electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Mandiwana, Khakhathi L.; Panichev, Nikolay

2010-01-01

Solid Certified Reference Materials (CRMs) with known vanadium(+5) content are currently not commercially available. Because of this, vanadium species have been determined in solid CRMs of soil, viz. CRM023-50, CRM024-50, CRM049-50, SQC001 and SQC0012. These CRMs are certified with only total vanadium content. Vanadium(+5) was extracted from soil reference materials with 0.1 M Na 2 CO 3 . The quantification of V(+5) was carried out by electrothermal atomic absorption spectrometry (ET-AAS). The concentration of V(+5) in the analyzed CRMs was found to be ranging between 3.60 and 86.0 μg g -1 . It was also found that SQC001 contains approximately 88% of vanadium as V(+5) species. Statistical evaluation of the results of the two methods by paired t-test was in good agreement at 95% level of confidence.

Ab initio Investigation of Helium in Vanadium Oxide Nanoclusters

Science.gov (United States)

Danielson, Thomas; Tea, Eric; Hin, Celine

Nanostructured ferritic alloys (NFAs) are strong candidate materials for the next generation of fission reactors and future fusion reactors. They are characterized by a large number density of oxide nanoclusters dispersed throughout a BCC iron matrix, where current oxide nanoclusters are primarily comprised of Y-Ti-O compounds. The oxide nanoclusters provide the alloy with high resistance to neutron irradiation, high yield strength and high creep strength at the elevated temperatures of a reactor environment. In addition, the oxide nanoclusters serve as trapping sites for transmutation product helium providing substantially increased resistance to catastrophic cracking and embrittlement. Although the mechanical properties and radiation resistance of the existing NFAs is promising, the problem of forming large scale reactor components continues to present a formidable challenge due to the high hardness and unpredictable fracture behavior of the alloys. An alternative alloy has been previously proposed and fabricated where vanadium is added in order to form vanadium oxide nanoclusters that serve as deflection sites for crack propagation. Although experiments have shown evidence that the fracture behavior of the alloys is improved, it is unknown whether or not the vanadium oxide nanoclusters are effective trapping sites for helium. We present results obtained using density functional theory investigating the thermodynamic stability of helium with the vanadium oxide matrix to make a comparison of trapping effectiveness to traditional Y-Ti-O compounds.

Modeling of ion transport through a porous separator in vanadium redox flow batteries

Science.gov (United States)

Zhou, X. L.; Zhao, T. S.; An, L.; Zeng, Y. K.; Wei, L.

2016-09-01

In this work, we develop a two-dimensional, transient model to investigate the mechanisms of ion-transport through a porous separator in VRFBs and their effects on battery performance. Commercial-available separators with pore sizes of around 45 nm are particularly investigated and effects of key separator design parameters and operation modes are explored. We reveal that: i) the transport mechanism of vanadium-ion crossover through available separators is predominated by convection; ii) reducing the pore size below 15 nm effectively minimizes the convection-driven vanadium-ion crossover, while further reduction in migration- and diffusion-driven vanadium-ion crossover can be achieved only when the pore size is reduced to the level close to the sizes of vanadium ions; and iii) operation modes that can affect the pressure at the separator/electrode interface, such as the electrolyte flow rate, exert a significant influence on the vanadium-ion crossover rate through the available separators, indicating that it is critically important to equalize the pressure on each half-cell of a power pack in practical applications.

Technical assessment of vanadium-base alloys for fusion reactor applications

International Nuclear Information System (INIS)

Gold, R.E.; Harrod, D.L.; Ammon, R.L.; Buckman, R.W. Jr.; Svedberg, R.C.

1978-01-01

A large data base has been compiled on vanadium-base alloys but the data base on any one alloy is quite limited. Great flexibility exists in the composition-microstructure-property relationship and this facilitates alloy optimization to meet diverse property requirements. Tensile properties and creep properties of existing alloys exceed likely requirements. Fatigue strength, including crack growth rate, is probably the most critical material property but no data exists for vanadium alloys. Swelling and irradiated ductility behavior look promising but require further evaluation. Vanadium alloy-liquid metal compatibility, particularly interstitial mass transfer, may be equally as critical as fatigue behavior; viability cannot be established with the existing data base. Fabricability must be given early consideration in alloys selection to guard against potentially serious problems in subsequent scale-up and production

Fluorine doped vanadium dioxide thin films for smart windows

International Nuclear Information System (INIS)

Kiri, Pragna; Warwick, Michael E.A.; Ridley, Ian; Binions, Russell

2011-01-01

Thermochromic fluorine doped thin films of vanadium dioxide were deposited from the aerosol assisted chemical vapour deposition reaction of vanadyl acetylacetonate, ethanol and trifluoroacetic acid on glass substrates. The films were characterised with scanning electron microscopy, variable temperature Raman spectroscopy and variable temperature UV/Vis spectroscopy. The incorporation of fluorine in the films led to an increase in the visible transmittance of the films whilst retaining the thermochromic properties. This approach shows promise for improving the aesthetic properties of vanadium dioxide thin films.

Vanadium(IV)-stimulated hydrolysis of 2,3-diphosphoglycerate.

Science.gov (United States)

Stankiewicz, P J

1989-05-01

Vanadium(IV) stimulates the hydrolysis of 2,3-diphosphoglycerate at 23 degrees C. The pH optimum is 5.0. Reactions were analyzed by enzymatic and phosphate release assays. The products of 2,3-diphosphoglycerate hydrolysis are inorganic phosphate and 3-phosphoglycerate. The reaction is inhibited by high concentrations of 2,3-diphosphoglycerate and an equation has been formulated that describes the kinetic constants for this reaction at pH 7. The possible relevance of the reaction to the therapeutic lowering by vanadium(IV) of red cell 2,3-diphosphoglycerate in sickle-cell disease is discussed.

Measurement of secondary gamma-ray production cross sections of vanadium induced by D-T neutrons

International Nuclear Information System (INIS)

Kondo, Tetsuo; Murata, Isao; Takahashi, Akito

1999-01-01

The secondary gamma-ray production cross sections of vanadium induced by D-T neutrons have been measured. The experimental values were compared with the theoretical calculation results by SINCROS-II and the evaluation result based on experimental data compiled by Simakov. The calculation results supported our data, while Simakov's evaluation did not agree with the present result very well. (author)

Sex-based differences in lymphocyte proliferation in the spleen after vanadium inhalation.

Science.gov (United States)

Rodriguez-Lara, Vianey; Muñiz-Rivera Cambas, Angelica; González Villalva, Adriana; Fortoul, Teresa I

2016-07-01

Vanadium (V) is a transition metal often adhered to particulate matter and released into the atmosphere as vanadium pentoxide (V2O5) by the burning of fossil fuels. This air pollutant causes adverse effects in the immune system. Lymphocytosis and splenomegaly have been reported with increased white pulp in mice after V inhalation. The effect of V on the immune system as related to sex has been poorly investigated. This study sought to determine if V inhalation (a) produced lymphoproliferation that could explain the changes previously observed in the spleen and in peripheral blood lymphocyte counts and (b) whether any observed effects differed due to gender. Immunohistochemical analyses of Ki-67, a specific proliferation marker, was made in the spleens of CD-1 male and female mice exposed for 1 h, twice a week, over a 12-week period to V2O5 (at 1.4 mg V2O5/m(3)) by whole-body inhalation; similar analyses were performed on spleens of control mice exposed to vehicle (filtered air). The results showed that in male mice there was a significant increase in percentage of Ki-67 immunopositive lymphocytes starting from the second week and until the end of the exposure. The Ki-67 signal was cytoplasmic and nuclear in the exposed males, while in controls the signal was only nuclear. In female mice, V inhalation singificantly increased the percentage of proliferating lymphocytes only after 1 week of exposure. Ki-67 signal was observed only in the nucleus of lymphocytes from the control and exposed females. The results here help to explain the splenomegaly and lymphocytosis observed previously in male mice and support the lymphoproliferative effect induced by V. Lastly, the finding that there was a sex difference in the effect of vanadium on lymphocyte proliferation suggests a role for sex hormones in potential protection against V immunotoxicity; however, further studies are needed to support this hypothesis.

A simple spectrophotometric determination of trace amounts of vanadium using thionin

Directory of Open Access Journals (Sweden)

Tom Cherian

2005-12-01

Full Text Available A simple and sensitive spectrophotometric method has been developed for the determination of trace amounts of vanadium using thionin as a chromogenic reagent. The proposed method is based on the reaction of vanadium(V with potassium iodide in acid medium to liberate iodine, which bleaches the violet colour of thionin and is measured at 600 nm. This decrease in absorbance is directly proportional to the vanadium(V concentration and obeys Beer's law in the range of 0.2-10 μgmL-1 of V(V. The molar absorptivity, Sandell's sensitivity, detection limit and quantitation limit of the method were found to be 2.298 x 104 Lmol-1cm-1, 0.52 x 10-2 μgcm-2, 0.035 μgmL-1 and 0.11 μgmL-1, respectively. The optimum reaction conditions and other analytical conditions were evaluated. The effect of interfering ions on the determination is described. The developed method has been successfully applied to the analysis of the vanadium in synthetic and alloy samples.

Transport of vanadium (V in saturated porous media: effects of pH, ionic-strength and clay mineral

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Yulu Wang

2016-10-01

Full Text Available Vanadium, a hazardous pollutant, has been frequently detected in soil and groundwater, however, its transport behavior in porous media were not clearly understood. In this study, the effects of solution pH, ionic strength (IS and the effect of clay mineral on the transport of vanadium in saturated porous media were investigated. Laboratory experiments using a series of columns packed with quartz sand were carried out to explore the retention and transport of vanadium with a range of ionic-strength (0.001–0.1 M and pH (4–8 and two different types of clay minerals montmorillonite and kaolinite. Results of the breakthrough experiments showed that vanadium was highly mobile in the saturated porous media. The increase in pH rendered a higher transport of vanadium in saturated porous media. The study also indicated an easier transfer of vanadium with an increase in IS. Montmorillonite enhanced the mobility of vanadium in the column when compared to kaolinite. A mathematical model based on advection-dispersion equation coupled with equilibrium and kinetic reactions was used to describe the retention and transport of vanadium in the columns very well.

Insulin and vanadium protect against osteoarthritis development secondary to diabetes mellitus in rats.

Science.gov (United States)

El Karib, Abbas O; Al-Ani, Bahjat; Al-Hashem, Fahaid; Dallak, Mohammad; Bin-Jaliah, Ismaeel; El-Gamal, Basiouny; Bashir, Salah O; Eid, Refaat A; Haidara, Mohamed A

2016-07-01

Diabetic complications such as cardiovascular disease and osteoarthritis (OA) are among the common public health problems. The effect of insulin on OA secondary to diabetes has not been investigated before in animal models. Therefore, we sought to determine whether insulin and the insulin-mimicking agent, vanadium can protect from developing OA in diabetic rats. Type 1 diabetes mellitus (T1DM) was induced in Sprague-Dawley rats and treated with insulin and/or vanadium. Tissues harvested from the articular cartilage of the knee joint were examined by scanning electron microscopy, and blood samples were assayed for oxidative stress and inflammatory biomarkers. Eight weeks following the induction of diabetes, a profound damage to the knee joint compared to the control non-diabetic group was observed. Treatment of diabetic rats with insulin and/or vanadium differentially protected from diabetes-induced cartilage damage and deteriorated fibrils of collagen fibers. The relative biological potencies were insulin + vanadium > insulin > vanadium. Furthermore, there was about 2- to 5-fold increase in TNF-α (from 31.02 ± 1.92 to 60.5 ± 1.18 pg/ml, p 1) and IL-6 (from 64.67 ± 8.16 to 338.0 ± 38.9 pg/ml, p 1) cytokines and free radicals measured as TBARS (from 3.21 ± 0.37 to 11.48 ± 1.5 µM, p 1) in the diabetic group, which was significantly reduced with insulin and or vanadium. Meanwhile, SOD decreased (from 17.79 ± 8.9 to 8.250.29, p 1) and was increased with insulin and vanadium. The relative potencies of the treating agents on inflammatory and oxidative stress biomarkers were insulin + vanadium > insulin > vanadium. The present study demonstrates that co-administration of insulin and vanadium to T1DM rats protect against diabetes-induced OA possibly by lowering biomarkers of inflammation and oxidative stress.

Hydrogen release from irradiated vanadium alloy V-4Cr-4Ti

Energy Technology Data Exchange (ETDEWEB)

Klepikov, A.Kh. E-mail: klepikov@ietp.alma-ata.su; Romanenko, O.G.; Chikhray, Y.V.; Tazhibaeva, I.L.; Shestakov, V.P.; Longhurst, G.R. E-mail: gxl@inel.gov

2000-11-01

The present work is an attempt to obtain data concerning the influence of neutron and {gamma} irradiation upon hydrogen retention in V-4Cr-4Ti vanadium alloy. The experiments on in-pile loading of vanadium alloy specimens at the neutron flux density 10{sup 14} n/cm{sup 2} s, hydrogen pressure of 80 Pa, and temperatures of 563, 613 and 773 K were carried out using the IVG.1M reactor of the Kazakhstan National Nuclear Center. A preliminary set of loading/degassing experiments with non-irradiated material has been carried out to obtain data on hydrogen interaction with vanadium alloy. The, data presented in this work are related both to non-irradiated and irradiated samples.

Hydrogen release from irradiated vanadium alloy V-4Cr-4Ti

International Nuclear Information System (INIS)

Klepikov, A.Kh.; Romanenko, O.G.; Chikhray, Y.V.; Tazhibaeva, I.L.; Shestakov, V.P.; Longhurst, G.R.

2000-01-01

The present work is an attempt to obtain data concerning the influence of neutron and γ irradiation upon hydrogen retention in V-4Cr-4Ti vanadium alloy. The experiments on in-pile loading of vanadium alloy specimens at the neutron flux density 10 14 n/cm 2 s, hydrogen pressure of 80 Pa, and temperatures of 563, 613 and 773 K were carried out using the IVG.1M reactor of the Kazakhstan National Nuclear Center. A preliminary set of loading/degassing experiments with non-irradiated material has been carried out to obtain data on hydrogen interaction with vanadium alloy. The, data presented in this work are related both to non-irradiated and irradiated samples

Distributions of traces of metals on sorption from solutions of vanadium(V)

International Nuclear Information System (INIS)

Evseeva, N.K.; Turnaov, A.N.; Telegin, G.F.; Kremenskaya, I.N.

1983-01-01

A study is made of the distributions of traces of metals between aqueous solutions of vanadium(V) and a solid reagent made by introducing di-2-ethylhexylphosphoric acid into an inert matrix: a nonionic macroporous copolymer of polystyrene with divinyl benzene (wofatit Y 29). As regards degree of extraction, the trace components fall in the series zinc > cadmium > manganese > copper > cobalt, which resemble the extractability series. The vanadium content of the solution and the concentrations of the trace components have virtually no effect on the sorption. The process is effective in concentrating trace components from solutions containing vanadium(V)

Distribution of microimpurities of metals at their sorption from vanadium (5) solutions

International Nuclear Information System (INIS)

Evseeva, N.K.; Turanov, A.N.; Telegin, G.F.; Kremenskaya, I.N.

1983-01-01

Distribution of metal microimpurities (Zn, Mn, Cu, Co, Fe) between aqueous solutions of vanadium (5) and solid extracting agent, prepared by means of introduction of di-2-ethylhexylphosphoric acid into inert matrix-nonionogeneous macropore copolymer of polystyrene with divinylbenzene (vofatit Y-29), has been studied. Accroding to the degree of extraction the microimpurities are arranged in the series: zinc > cadmium > manganese > copper > cobalt, which is similar to the series of extractability. Vanadium content in solution and concentration of microimpurities practically does not affect the sorption. It has been established that the process is effective for microimpurities concentration from solutions containing vanadium (5)

Distribution of microimpurities of metals at their sorption from vanadium (5) solutions

Energy Technology Data Exchange (ETDEWEB)

Evseeva, N.K.; Turanov, A.N.; Telegin, G.F.; Kremenskaya, I.N.

1983-01-01

Distribution of metal microimpurities (Zn, Mn, Cu, Co, Fe) between aqueous solutions of vanadium (5) and solid extracting agent, prepared by means of introduction of di-2-ethylhexylphosphoric acid into inert matrix-nonionogeneous macropore copolymer of polystyrene with divinylbenzene (vofatit Y-29), has been studied. According to the degree of extraction the microimpurities are arranged in the series: zinc > cadmium > manganese > copper > cobalt, which is similar to the series of extractability. Vanadium content in solution and concentration of microimpurities practically does not affect the sorption. It has been established that the process is effective for microimpurities concentration from solutions containing vanadium (5).

Vanadium century record from Caribbean reef corals: A tracer of oil pollution in Panama

International Nuclear Information System (INIS)

Guzman, H.M.; Jarvis, K.E.

1996-01-01

The Caribbean region is potentially one of the largest oil-producing areas in the world, and contamination by petroleum is threatening the marine environment. Vanadium (V), an abundant element in crude oils, was used as proxy tracer of oil pollution along the Caribbean coast of Panama. We develop a century chronology based on the concentration of vanadium (using ICP-MS) incorporated into annual growth bands of coral skeletons. The chronology for vanadium showed a relatively clear pattern where background seawater concentrations were observed in the early history of the corals followed by an increase after 1962, the initiation of a refinery operation. The vanadium chronology suggests that a major degradation process in the coastal zone could have started around the 1960s, but we were unable to confirm such an assumption due to the lack of long-term ecological and pollution data. The gradual increase of vanadium into the marine environment might be used as a pointer to oil pollution. 46 refs, 4 figs, 1 tab

Confirmation of vanadium complex formation using electrospray mass spectrometry and determination of vanadium speciation by sample stacking capillary electrophoresis

International Nuclear Information System (INIS)

Chen Zuliang; Owens, Gary; Naidu, Ravendra

2007-01-01

Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time. Electrospray mass spectrometry (ES-MS) was used to confirm the formation of [VO 2 (HEDTA)] 2- and [VO(HEDTA)] 1- in solution. An electrolyte containing 25 mM phosphate, 0.25 mM tetradecyltrimethylammonium bromide (TTAB) at pH 5.5 was optimum for the separation of these anionic vanadium complexes. Sample stacking techniques, including large-volume sample stacking (LVSS) and field-amplified sample injection (FASI), were tested to improve the sensitivity. Best sensitivity was obtained using FASI, with detection limits of 0.001 μM, equivalent to 0.4 μg L -1 , for [VO 2 (HEDTA)] 2- and 0.01 μM, equivalent to 3.4 μg L -1 for [VO(HEDTA)] 1- . The utility of the method for the speciation of V(IV) and V(V) was demonstrated using ground water samples

The Influence of Vanadium Microalloying on the Production of Thin Slab Casting and Direct Rolled Steel Strip

Science.gov (United States)

Li, Yu; Milbourn, David

Vanadium microalloying is highly effective in high strength strip steels produced by thin slab casting and direct rolled process. Because of the high solubility of V(C,N) in austenite, vanadium is likely to remain in solution during casting, equalisation and rolling. Vanadium microalloyed steels have better hot ductility and are less prone to transverse cracking than niobium containing steels. Despite a coarse as-cast austenite grain size before rolling, significant grain refinement can be achieved in vanadium microalloyed steels by repeated recrystallization during rolling, resulting in a fine uniform ferrite microstructure in final strip. Almost all vanadium present in microalloyed steels is available to precipitate in ferrite as very fine particles, contributing to precipitation strengthening. Vanadium microalloyed steels show less sensitivity to rolling process variables and exhibit excellent combination of strength and toughness.

Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid-base properties on the oxidation of isopropanol

Directory of Open Access Journals (Sweden)

D. M. Meira

2006-09-01

Full Text Available Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450°C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene.

Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid base properties on the oxidation of isopropanol

Energy Technology Data Exchange (ETDEWEB)

Meira, D.M.; Cortez, G.G. [Faculdade de Engenharia Quimica de Lorena, Lorena, SP (Brazil). Dept. de Engenharia Quimica. Lab. de Catalise II]. E-mail: cortez@dequi.faenquil.br; Monteiro, W.R.; Rodrigues, J.A.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Combustao e Propulsao]. E-mail: jajr@lcp.inpe.br

2006-07-15

Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K{sub 2}CO{sub 3} as precipitant. The decomposition of these hydrotalcite precursors at 450 deg C yielded homogeneous MgyAlOx mixed oxides that contain the Al{sup +3} cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR) and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V{sup +5} decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene. (author)

Vanadium and heat treatments effect on elastic characteristics of niobium

International Nuclear Information System (INIS)

Vasil'eva, E.V.; Tret'yakov, V.I.; Prokoshkin, D.A.; Pustovalov, V.A.

1975-01-01

The effect of vanadium content and of heat treatment conditions on the elastic properties of niobium at temperatures of 20 to 800 deg C was studied. Nb-V alloys were produced by binary vacuum remelting. The Nb-V alloys have been then subjected to thermal treatment. The total degree of deformation amounts to about 95%. The specimens were tested with a view to determine their microhardness, specific electric resistance, elasticity limit and modulus of elasticity. The elastic limit of niobium rises when alloyed with vanadium. With the increase of vanadium content the elastic limit of the alloy becomes greater. Pre-crystallization annealing at 600 - 700 deg C considerably increases the elastic limit, which is explained by development of the thermally activated processes leading to a decrease of dislocation mobility and thereby to a strengthening of the alloy

Interaction of titanium and vanadium with carbon dioxide in heating

International Nuclear Information System (INIS)

Vlasyuk, R.Z.; Kurovskii, V.Y.; Lyapunov, A.P.; Radomysel'skii, I.D.

1986-01-01

To obtain prediction data on the change in properties of titaniumand vanadium-base powder metallurgy materials operating in a carbon dioxide atmosphere, and also to clarify the mechanism of their interaction with the gas in this work, gravimetric investigations of specimens heated at temperatures of 300-1000 C and an x-ray diffraction analysis of their surface were made and the composition of the gas in the heating chamber was studied. The results of the investigations indicate a similarity between the mechanisms of interaction of titanium and vanadium with carbon dioxide including the formation of oxides on the surface of the metal with subsequent carbidization at temperatures above 800 C. On the basis of the data obtained, it may be concluded that the operating temperature limits of titanium- or vanadium-base materials in carbon dioxide must not exceed 400 and 600 C, respectively

Investigation of structural, morphological and electrical properties of APCVD vanadium oxide thin films

International Nuclear Information System (INIS)

Papadimitropoulos, Georgios; Trantalidis, Stelios; Tsiatouras, Athanasios; Vasilopoulou, Maria; Davazoglou, Dimitrios; Kostis, Ioannis

2015-01-01

Vanadium oxide films were chemically vapor deposited (CVD) on oxidized Si substrates covered with CVD tungsten (W) thin films and on glass substrates covered with indium tin oxide (ITO) films, using vanadium(V) oxy-tri-isopropoxide (C 9 H 21 O 4 V) vapors. X-ray diffraction (XRD) measurements showed that the deposited films were composed of a mixture of vanadium oxides; the composition was determined mainly by the deposition temperature and less by the precursor temperature. At temperatures up to 450 C the films were mostly composed by monoclinic VO 2 . Other peaks corresponding to various vanadium oxides were also observed. X-ray microanalysis confirmed the composition of the films. The surface morphology was studied with atomic force microscopy (AFM) and scanning electron microscopy (SEM). These measurements revealed that the morphology strongly depends on the used substrate and the deposition conditions. The well-known metal-insulator transition was observed near 75 C for films mostly composed by monoclinic VO 2 . Films deposited at 450 C exhibited two transitions one near 50 C and the other near 60 C possibly related to the presence of other vanadium phases or of important stresses in them. Finally, the vanadium oxide thin films exhibited significant sensory capabilities decreasing their resistance in the presence of hydrogen gas with response times in the order of a few seconds and working temperature at 40 C. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Influence of vanadium doping on the electrochemical behaviour of MnO{sub 2} rutile; Influence du dopage par le vanadium sur le comportement electrochimique de MnO{sub 2} rutile

Energy Technology Data Exchange (ETDEWEB)

Delmas, C. [Centre National de la Recherche Scientifique (CNRS), 33 - Pessac (France). Institut de Chimie de la Matiere Condensee de Bordeaux; Capitaine, F.; Majastre [Bollore Technologies, 29 - Quimper (France); Baudry, P. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches

1996-12-31

Vanadium doped manganese bi-oxide has been obtained from a solution containing both cations. The X-ray diffraction of this material indicates a rutile-type phase but the enlargement of some lines supports the existence of several lattice defects. Also the particle size of the doped material is significantly smaller than the one of the non-doped material obtained in the same conditions. The presence of pentavalent vanadium inside the lattice leads to a small amount of trivalent manganese. Electron microscopy shows the existence of defects which have a tendency of becoming well-ordered and to stabilize a sur-structure. At ambient temperature, the electrochemical behaviour of doped manganese bi-oxide is greatly improved when compared to the non-doped phase. This behaviour is due to the presence of numerous lattice defects and to the smaller size of crystallites. In polymer batteries, the behaviour is similar the one of the non-doped material for which the kinetics performances are improved by the cycling at 100 deg. C. Abstract only. (J.S.)

Influence of vanadium doping on the electrochemical behaviour of MnO{sub 2} rutile; Influence du dopage par le vanadium sur le comportement electrochimique de MnO{sub 2} rutile

Energy Technology Data Exchange (ETDEWEB)

Delmas, C [Centre National de la Recherche Scientifique (CNRS), 33 - Pessac (France). Institut de Chimie de la Matiere Condensee de Bordeaux; Capitaine, F; Majastre, [Bollore Technologies, 29 - Quimper (France); Baudry, P [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches

1997-12-31

Vanadium doped manganese bi-oxide has been obtained from a solution containing both cations. The X-ray diffraction of this material indicates a rutile-type phase but the enlargement of some lines supports the existence of several lattice defects. Also the particle size of the doped material is significantly smaller than the one of the non-doped material obtained in the same conditions. The presence of pentavalent vanadium inside the lattice leads to a small amount of trivalent manganese. Electron microscopy shows the existence of defects which have a tendency of becoming well-ordered and to stabilize a sur-structure. At ambient temperature, the electrochemical behaviour of doped manganese bi-oxide is greatly improved when compared to the non-doped phase. This behaviour is due to the presence of numerous lattice defects and to the smaller size of crystallites. In polymer batteries, the behaviour is similar the one of the non-doped material for which the kinetics performances are improved by the cycling at 100 deg. C. Abstract only. (J.S.)

Tritium removal using vanadium hydride

International Nuclear Information System (INIS)

Hill, F.B.; Wong, Y.W.; Chan, Y.N.

1978-01-01

The results of an initial examination of the feasibility of separation of tritium from gaseous protium-tritium mixtures using vanadium hydride in cyclic processes is reported. Interest was drawn to the vanadium-hydrogen system because of the so-called inverse isotope effect exhibited by this system. Thus the tritide is more stable than the protide, a fact which makes the system attractive for removal of tritium from a mixture in which the light isotope predominates. The initial results of three phases of the research program are reported, dealing with studies of the equilibrium and kinetics properties of isotope exchange, development of an equilibrium theory of isotope separation via heatless adsorption, and experiments on the performance of a single heatless adsorption stage. In the equilibrium and kinetics studies, measurements were made of pressure-composition isotherms, the HT--H 2 separation factors and rates of HT--H 2 exchange. This information was used to evaluate constants in the theory and to understand the performance of the heatless adsorption experiments. A recently developed equilibrium theory of heatless adsorption was applied to the HT--H 2 separation using vanadium hydride. Using the theory it was predicted that no separation would occur by pressure cycling wholly within the β phase but that separation would occur by cycling between the β and γ phases and using high purge-to-feed ratios. Heatless adsorption experiments conducted within the β phase led to inverse separations rather than no separation. A kinetic isotope effect may be responsible. Cycling between the β and γ phases led to separation but not to the predicted complete removal of HT from the product stream, possibly because of finite rates of exchange. Further experimental and theoretical work is suggested which may ultimately make possible assessment of the feasibility and practicability of hydrogen isotope separation by this approach

NEXAFS characterization and reactivity studies of bimetallic vanadium molybdenum oxynitride hydrotreating catalysts

Energy Technology Data Exchange (ETDEWEB)

Kapoor, R.; Oyama, S.T. [Virginia Polytechnic Inst., Blacksburg, VA (United States); Fruehberger, B.; Chen, J.G. [Exxon Research and Engineering Company, Annandale, NJ (United States)

1997-02-27

The surface and bulk compositions of vanadium molybdenum oxynitride (V{sub 2}MoO{sub 1.7}N{sub 2.4}), prepared by temperature-programmed reaction (TPR) of vanadium molybdenum oxide (V{sub 2}MoO{sub 8}) with ammonia, have been characterized using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NEXAFS data were recorded at the K-edges of nitrogen and oxygen, the L-edge of vanadium, and the M-edge of molybdenum. The nitrogen K-edge region of V-Mo oxynitride shows the characteristic NEXAFS features of early-transition-metal nitrides, although these features are different from those of either VN or Mo{sub 2}N. Furthermore, comparison of the electron yield and fluorescence yield measurements also reveals that the oxidation state is different for vanadium near the surface region and for vanadium in the bulk, which is estimated to be 2.8 {+-} 0.3 and 3.8 {+-} 0.3, respectively. The oxidation state of bulk molybdenum is also estimated to be 4.4 {+-} 0.3. The X-ray diffraction pattern shows that the bulk phase of the bimetallic oxide is different from the pure monometallic oxide phases but the oxynitride has a cubic structure that resembles the pure vanadium and molybdenum nitride phases. The V-Mo oxide as prepared shows a preferential orientation of [001] crystallographic planes which is lost during the nitridation process. This shows that the solid state transformation V{sub 2}MoO{sub 8} {yields} V{sub 2}MoO{sub 1.7}N{sub 2.4} is not topotactic. 27 refs., 8 figs., 1 tab.

The use of vanadium as a scattering standard for pulsed source neutron spectrometers

International Nuclear Information System (INIS)

Mayers, J.

1983-06-01

The Gaussian approximation for multiphonon cross-sections has been used in a calculation of the variation of vanadium cross-sections with incident neutron energy. The results show that vanadium behaves as an elastic scatterer to within a few percent on pulsed neutron spectrometers with incident neutron energies up to 1 eV. There is a calculated anisotropy in the scattering of 8%. It is found that the scattering properties of vanadium at 77K and 293K differ by a maximum of 1% except for neutron energies < 15 meV. (author)

Improving methane gas sensing properties of multi-walled carbonnanotubes by vanadium oxide filling

CSIR Research Space (South Africa)

Chimowa, George

2017-08-01

Full Text Available Manipulation of electrical properties and hence gas sensing properties of multi-walled carbon nanotubes (MWNTs) by filling the inner wall with vanadium oxide is presented. Using a simple capillary technique, MWNTs are filled with vanadium metal...

Antimicrobial activity of aroylhydrazone-based oxido vanadium(v) complexes: in vitro and in silico studies

Czech Academy of Sciences Publication Activity Database

Ebrahimipour, S.Y.; Sheikhshoaie, I.; Simpson, J.; Ebrahimnejad, H.; Dušek, Michal; Kharazmi, N.; Eigner, Václav

2016-01-01

Roč. 40, č. 3 (2016), s. 2401-2412 ISSN 1144-0546 R&D Projects: GA ČR GA15-12653S; GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : Schiff bases * oxido-vanadium complexes * antimictobial activity * crystal structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.269, year: 2016

Some Ternary Phenylmethoxybis(tetrazolium) Complexes of Vanadium(IV,V) and Their Constants of Association

OpenAIRE

Gavazov, Kiril Blazhev; Racheva, Petya Vasileva; Lekova, Vanya Dimitrova; Dimitrov, Atanas Nikolov; Türkyilmaz, Murat; Genç, Fatma

2012-01-01

Several liquid-liquid extraction systems containing vanadium {vanadium(IV) or vanadium(V)}, azoderivative of resorcinol {ADR: 4-(2-pyridylazo)-resorcinol (PAR) or 4-(2-thiazolylazo)-resorcinol (TAR)} and (phenylmethoxibis)tetrazolium salts {MBT: 3,3'-(3,3'-dimetoxy-4,4'-biphenylene)-bis(2,5-diphenyl-2H-tetrazolium) chloride (Blue Tetrazolium, BT) or 3,3'-(3,3'-dimetoxy-4,4'-biphenylene)-bis[2,5-di(4-nitrophenyl)-2H-tetrazolium] chloride (Tetranitroblue Tetrazolium, TNBT)} were studied. The op...

Atomic layer deposition of VO{sub 2} films with Tetrakis-dimethyl-amino vanadium (IV) as vanadium precursor

Energy Technology Data Exchange (ETDEWEB)

Lv, Xinrui [Key Laboratory of Inorganic Coating Materials CAS, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Cao, Yunzhen, E-mail: yzhcao@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials CAS, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); Yan, Lu; Li, Ying; Song, Lixin [Key Laboratory of Inorganic Coating Materials CAS, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

2017-02-28

Highlights: • VO{sub 2} film was easily deposited by ALD using novel vanadium precursor V(NMe{sub 2}){sub 4}. • Deposition and annealing condition were systematically investigated. • Comparable transition properties of VO{sub 2} film on resistance and spectral transmittance were studied. - Abstract: VO{sub 2} thin films have been grown on Si(100) (VO{sub 2}/Si) and fused silica substrates (VO{sub 2}/SiO{sub 2}) by atomic layer deposition (ALD) using tetrakis-dimethyl-amino vanadium (IV) (TDMAV) as a novel vanadium precursor and water as reactant gas. The quartz crystal microbalance (QCM) measurement was performed to study the ALD process of VO{sub 2} thin film deposition, and a constant growth rate of about 0.95 Å/cycle was obtained at the temperature range of 150–200 °C. XRD measurement was performed to study the influence of deposition temperature and post-annealing condition on the crystallization of VO{sub 2} films, which indicated that the films deposited between 150 and 200 °C showed well crystallinity after annealing at 475 °C for 100 min in Ar atmosphere. XPS measurement verified that the vanadium oxidation state was 4+ for both as-deposited film and post-annealed VO{sub 2}/Si film. AFM was applied to study the surface morphology of VO{sub 2}/Si films, which showed a dense polycrystalline film with roughness of about 1 nm. The resistance of VO{sub 2}/Si films deposited between 150 °C and 200 °C as a function of temperature showed similar semiconductor-to-metal transition (SMT) characters with the transition temperature for heating branch (T{sub c,h}) of about 72 °C, a hysteresis width of about 10 °C and the resistance change of two orders of magnitude. The increase of T{sub c,h} compared with the bulk VO{sub 2} (68 °C) may be attributed to the tensile stress along the c-axis in the film. Transmittance measurement of VO{sub 2}/SiO{sub 2} films showed typical thermochromic property with a NIR switching efficiency of above 50% at 2 μm across

The electron distribution in vanadium

International Nuclear Information System (INIS)

Weiss, R.J.

1978-01-01

It is shown that the apparent discrepancy for b.c.c. vanadium metal between the charge density and small momentum density anisotropies can be resolved by contracting the 3d triply-degenerate radial wavefunctions which point towards the nearest neighbours and expanding the 3d doubly-degenerate radial wave-functions which point towards the second-nearest neighbours. (author)

The preparation of titanium-vanadium carbide/nickel cermets. Technical report

International Nuclear Information System (INIS)

Precht, W.; Sprissler, B.

1976-01-01

Titanium/vanadium alloy carbide rods were prepared by a zone melting procedure. Wetting studies were carried out using sections of the fused rods and candidate matrix material. It was established that nickel exhibits excellent wetting of (Ti, V) C, and accordingly cermet blends were prepared and liquid phase sintered. Processing parameters are discussed as well as their effect on the final microstructure. Alternate methods for cermet preparation are offered which use as received titanium carbide and vanadium carbide powders

Use of imidazole 4,5-dicarboxylic acid in vanadium speciation

International Nuclear Information System (INIS)

Banerjee, D.; Mondal, B.C.; Das, D.; Das, A.K.

2003-01-01

A new resin has been synthesized by fictionalization of polystyrene-divinylbenzene (8 %) with imidazole 4,5-dicarboxylic acid through -N=N- bonding. The resulting resin has been characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy, hydrogen ion capacity and metal ion capacity. The speciation study of vanadium has been studied by using this resin and the maximum exchange capacity was found to be 0.45 mmol g -1 for V 4+ and that for V 5+ was 1.57 mmol g -1 at pH 3 for both. The eluents malonic acid and sodium hydroxide have been used for the selective separation of vanadium(IV) and vanadium(V) species respectively. The effects of diverse ions on the sorption and recovery of each species have been studied. Finally, the developed method has been applied for the speciation and determination of these two species in natural water samples. (author)

Vanadium oxide nanotubes as cathode material for Mg-ion batteries

DEFF Research Database (Denmark)

Christensen, Christian Kolle; Sørensen, Daniel Risskov; Bøjesen, Espen Drath

Vanadium oxide compounds as cathode material for secondary Li-ion batteries gained interest in the 1970’s due to high specific capacity (>250mAh/g), but showed substantial capacity fading.1 Developments in the control of nanostructured morphologies have led to more advanced materials, and recently...... vanadium oxide nanotubes (VOx-NT) were shown to perform well as a cathode material for Mg-ion batteries.2 The VOx-NTs are easily prepared via a hydrothermal process to form multiwalled scrolls of VO layer with primary amines interlayer spacer molecules.3 The tunable and relative large layer spacing 1-3 nm...... synchrotron powder X-ray diffraction measured during battery operation. These results indicate Mg-intercalation in the multiwalled VOx-NTs occurs within the space between the individual vanadium oxide layers while the underlying VOx frameworks constructing the walls are affected only to a minor degree...

Structure and function of vanadium haloperoxidases

NARCIS (Netherlands)

Wever, R.; Michibata, H.

2012-01-01

Vanadium haloperoxidases contain the bare metal oxide vanadate as a prosthetic group and differ strongly from the heme peroxidases in substrate specificity and molecular properties. The substrates of these enzymes are limited to halides and sulfides, which in the presence of hydrogen peroxide are

Fundamental irradiation studies on vanadium alloys

International Nuclear Information System (INIS)

Loomis, B.A.; Garner, F.A.; Ermi, A.M.

1985-05-01

A joint experiment on the irradiation response of simple vanadium alloys has been initiated under the auspices of the DAFS and BES progams. Specimen fabrication is nearly complete and the alloys are expected to be irradiated in lithium in FFTF-MOTA Cycles 7 and 8

Confirmation of vanadium complex formation using electrospray mass spectrometry and determination of vanadium speciation by sample stacking capillary electrophoresis

Energy Technology Data Exchange (ETDEWEB)

Chen Zuliang [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia)]. E-mail: zuliang.chen@unisa.edu.au; Owens, Gary [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravendra [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC for Contamination Assessment and Remediation of Environments, Mawson Lakes Boulevard, Mawson Lakes, SA 5095 (Australia)

2007-02-28

Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time. Electrospray mass spectrometry (ES-MS) was used to confirm the formation of [VO{sub 2}(HEDTA)]{sup 2-} and [VO(HEDTA)]{sup 1-} in solution. An electrolyte containing 25 mM phosphate, 0.25 mM tetradecyltrimethylammonium bromide (TTAB) at pH 5.5 was optimum for the separation of these anionic vanadium complexes. Sample stacking techniques, including large-volume sample stacking (LVSS) and field-amplified sample injection (FASI), were tested to improve the sensitivity. Best sensitivity was obtained using FASI, with detection limits of 0.001 {mu}M, equivalent to 0.4 {mu}g L{sup -1}, for [VO{sub 2}(HEDTA)]{sup 2-} and 0.01 {mu}M, equivalent to 3.4 {mu}g L{sup -1} for [VO(HEDTA)]{sup 1-}. The utility of the method for the speciation of V(IV) and V(V) was demonstrated using ground water samples.

Nature of active vanadium nanospecies in MCM-41 type catalysts for olefins oxidation

Energy Technology Data Exchange (ETDEWEB)

Chanquía, Corina M., E-mail: cchanquia@cab.cnea.gov.ar [Centro Atómico Bariloche, Comisión Nacional de Energía Atómica (CAB-CNEA). Av. Bustillo 9500, R8402AGP, San Carlos de Bariloche, Río Negro (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Avenida Rivadavia 1917, C1033AAJ, Ciudad Autónoma de Buenos Aires (Argentina); Cánepa, Analía L. [Centro de Investigación y Tecnología Química (CITeQ), Universidad Tecnológica Nacional, Facultad Regional Córdoba (UTN-FRC), Maestro López esq. Cruz Roja Argentina, Ciudad Universitaria, 5016, Córdoba Capital (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Avenida Rivadavia 1917, C1033AAJ, Ciudad Autónoma de Buenos Aires (Argentina); Winkler, Elin L. [Centro Atómico Bariloche, Comisión Nacional de Energía Atómica (CAB-CNEA). Av. Bustillo 9500, R8402AGP, San Carlos de Bariloche, Río Negro (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Avenida Rivadavia 1917, C1033AAJ, Ciudad Autónoma de Buenos Aires (Argentina); and others

2016-06-01

A multi-technique physicochemical investigation including UV–Vis-DRS, Raman spectroscopy, XPS, ESR and FTIRS with pyridine adsorption was performed to analyze the nature of different vanadium nanospecies present on MCM-41 type catalysts. By employing a direct hydrothermal synthesis, vanadium species were incorporated into siliceous structure mainly as tetrahedrally coordinated isolated V{sup δ+} ions, which would be located inside the wall and on the wall surface of the mesoporous channels. The coexistence of both vanadium oxidation states V{sup 4+} and V{sup 5+} was also revealed. Acidity measurements permitted to infer about the majority presence of Lewis acid sites, which increase with vanadium content. The catalytic performance of these materials was evaluated in the reaction of α-pinene oxidation with H{sub 2}O{sub 2}. The highest intrinsic activity of the sample with lower V loading was attributed to the high dispersion and efficiency of the isolated V{sup δ+} species that actuate as active sites. A mixture of reaction products arising from competitive processes of epoxidation and allylic oxidation was found. - Highlights: • Nature of vanadium nanospecies in mesoporous silicates was investigated. • From hydrothermal sol–gel synthesis, isolated V{sup δ+} sites were mainly generated. • The coexistence of both vanadium oxidation states V{sup 4+} and V{sup 5+} was revealed. • The catalytic performance was evaluated in α-pinene oxidation with H{sub 2}O{sub 2}. • The high catalytic activity is attributed to high dispersion of isolated V{sup δ+} ions.

Coupled Membrane Transport Parameters for Ionic Species in All-Vanadium Redox Flow Batteries

International Nuclear Information System (INIS)

Ashraf Gandomi, Yasser; Aaron, D.S.; Mench, M.M.

2016-01-01

Highlights: • Real-time crossover of vanadium species was investigated with a novel system. • Concentration and electrostatic potential gradient-induced crossover was separated. • Interaction coefficients were introduced to account for state of charge dependence. • Electric-field-induced crossover is asymmetric for charge and discharge processes. • Net vanadium crossover is from negative to positive half-cell at open-circuit. - Abstract: One of the major sources of capacity loss in all-vanadium redox flow batteries (VRFBs) is the undesired transport of active vanadium species across the ion-exchange membrane, generically termed crossover. In this work, a novel system has been designed and built to investigate the concentration- and electrostatic potential gradient-driven crossover for all vanadium species through the membrane in real-time. For this study, a perfluorosulphonic acid membrane separator (Nafion ® 117) was used. The test system utilizes ultraviolet/visible (UV/Vis) spectroscopy to differentiate vanadium ion species and separates contributions to crossover stemming from concentration and electrostatic potential gradients. It is shown that the rate of species transport through the ion-exchange membrane is state of charge dependent and, as a result, interaction coefficients have been deduced which can be used to better estimate expected crossover over a range of operating conditions. The electric field was shown to increase the negative-to-positive transport of V(II)/V(III) and suppress the positive-to-negative transport of V(IV)/V(V) during discharge, with an inverse trend during charging conditions. Electric-field-induced transport coefficients were deduced directly from experimental data.

Vanadium in fuel oil - a new solution

Energy Technology Data Exchange (ETDEWEB)

Czech, N. [Siemens, Muelheim (Germany); Finckh, H. [Siemens, Erlangen (Germany)

1998-11-01

Hot corrosion of the hot-gas-path components due to vanadium contamination is one of the hazards associated with heavy residual oil combustion in heavy-duty gas turbines. This economically attractive oil combustion process has benefited from the recently developed vanadium inhibition technique, which is currently being tested at the Valladolid 220 MWe combined cycle plant in Mexico. The method uses atomization of a dilute aqueous solution of Epsom salt (MgSO{sub 7},7H{sub 2}O) into very small droplets which are then injected onto the flame where intensive mixing takes place. The successful use of this new technique promises extended operating periods between cleanup operations, and cost reductions from the use of inexpensive materials, as well as the ability to operate advanced gas turbines on difficult fuels, not previously feasible. (UK)

Microadditions of boron and vanadium in ADI

Directory of Open Access Journals (Sweden)

Rzychoń T.

2007-01-01

Full Text Available In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI. Melts were conducted with iron-nickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.

Di-4-octylphenylphosphoric acid as extractant : extraction of vanadium (IV) and beryllium

International Nuclear Information System (INIS)

Gajankush, R.B.

1976-01-01

The extraction of vanadium and beryllium has been studied using di-4-octylphenyl phosphoric acid (DOPPA) as metal extractant. The factors which affect the extraction have been studied in detail. An attempt has been made to clarify the mechanism of extraction and compare the results with those reported for di-2-ethylhexyl phosphoric acid (DEHPA). In the case of vanadium it was found that vanadium (IV) is more suitable for extraction. Synergistic extractionwas observed in the presence of neutral organophosphorous compounds like tri-n-butyl phosphate (TBP), dibutyl butyl phosphate (DBBP) and tri-n-octyl phosphine oxide (TOPO). The possibility of separating vanadium and uranium when they are present together in leach solutions has also been studied. The extraction of beryllium was found to be a slow process. The factors controlling the rate as well as the extent of extraction have been investigated. However, the results showed that in both respects DOPPA is better than DEHPA which was earlier studied by other authors. The separation of aluminium from beryllium has also been studied. (author)

Anthropogenic vanadium emissions to air and ambient air concentrations in North-West Europe

NARCIS (Netherlands)

Visschedijk, A.H.J.; Denier van der Gon, H.A.C.; Hulskotte, J.H.J.; Quass, U.

2013-01-01

An inventory of Vanadium emissions for North-West Europe for the year 2005 was made based on an identification of the major sources. The inventory covers Belgium, Germany, Denmark, France, United Kingdom, Luxembourg, Netherlands and the OSPAR region of the North Sea. Vanadium emission were

Critical V2O5/TeO2 Ratio Inducing Abrupt Property Changes in Vanadium Tellurite Glasses.

Science.gov (United States)

Kjeldsen, Jonas; Rodrigues, Ana C M; Mossin, Susanne; Yue, Yuanzheng

2014-12-26

Transition metal containing glasses have unique electrical properties and are therefore often used for electrochemical applications, such as in batteries. Among oxide glasses, vanadium tellurite glasses exhibit the highest electronic conductivity and thus the high potential for applications. In this work, we investigate how the dynamic and physical properties vary with composition in the vanadium tellurite system. The results show that there exists a critical V(2)O(5) concentration of 45 mol %, above which the local structure is subjected to a drastic change with increasing V(2)O(5), leading to abrupt changes in both hardness and liquid fragility. Electronic conductivity does not follow the expected correlation to the valence state of the vanadium as predicted by the Mott-Austin equation but shows a linear correlation to the mean distance between vanadium ions. These findings could contribute to designing optimum vanadium tellurite compositions for electrochemical devices. The work gives insight into the mechanism of electron conduction in the vanadium tellurite systems.

Luminescent Eu3+-doped transparent alumina ceramics with high hardness

Czech Academy of Sciences Publication Activity Database

Drdlíková, K.; Klement, R.; Hadraba, Hynek; Drdlík, D.; Galusek, D.; Maca, K.

2017-01-01

Roč. 37, č. 14 (2017), s. 4271-4277 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) LQ1601; GA ČR(CZ) GA15-06390S Institutional support: RVO:68081723 Keywords : Aluminia * Europium * Photoluminescence (PL) spectra * Submicrocrystalline powders Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass OBOR OECD: Ceramic s Impact factor: 3.411, year: 2016

Improved capacitance characteristics of electrospun ACFs by pore size control and vanadium catalyst.

Science.gov (United States)

Im, Ji Sun; Woo, Sang-Wook; Jung, Min-Jung; Lee, Young-Seak

2008-11-01

Nano-sized carbon fibers were prepared by using electrospinning, and their electrochemical properties were investigated as a possible electrode material for use as an electric double-layer capacitor (EDLC). To improve the electrode capacitance of EDLC, we implemented a three-step optimization. First, metal catalyst was introduced into the carbon fibers due to the excellent conductivity of metal. Vanadium pentoxide was used because it could be converted to vanadium for improved conductivity as the pore structure develops during the carbonization step. Vanadium catalyst was well dispersed in the carbon fibers, improving the capacitance of the electrode. Second, pore-size development was manipulated to obtain small mesopore sizes ranging from 2 to 5 nm. Through chemical activation, carbon fibers with controlled pore sizes were prepared with a high specific surface and pore volume, and their pore structure was investigated by using a BET apparatus. Finally, polyacrylonitrile was used as a carbon precursor to enrich for nitrogen content in the final product because nitrogen is known to improve electrode capacitance. Ultimately, the electrospun activated carbon fibers containing vanadium show improved functionality in charge/discharge, cyclic voltammetry, and specific capacitance compared with other samples because of an optimal combination of vanadium, nitrogen, and fixed pore structures.

Structural, physical and electrochemical characteristics of a vanadium oxysulfide, a cathode material for lithium batteries

Science.gov (United States)

Ouvrard, G.; Tchangbédji, G.; Deniard, P.; Prouzet, E.

A vanadium oxysulfide is obtained by a reaction between water solutions of a vanadyl salt and sodium sulfide at room temperature. After drying under mild conditions, the formulation of this phase is V 2O 3S·3H 2O. Thermogravimetric analyses show that it is not possible to remove completely water without losing sulfur. This is in agreement with proton nuclear magnetic resonance experiments which prove that water molecules are tightly bonded to vanadium. Magnetic susceptibility and X-ray absorption spectroscopy measurements allow to define the oxidation states of vanadium and sulfur, (IV) and (-II) respectively. From extended X-ray absorption fine structure spectroscopy at the vanadium K edge and infrared spectroscopy, the local structure around vanadium can be defined as a distorted octahedron, with a vanadyl bond and an opposite sulfur atom. Magnetic susceptibility and X-ray absorption spectroscopy measurements on chemically lithiated compounds show a complex charge transfer from lithium to the host structure upon lithium intercalation. If it appears that vanadium atoms are reduced, a possible role of sulfur atoms in the redox process has to be considered. Cycling tests of lithium batteries whose positive consists of oxysulfide are promising with 70 cycles under a regime of {C}/{8}, without noticeable loss in capacity of 120 Ah/kg.

Fluorometric determination of vanadium (V) by utilizing its catalytic effect on the oxidation of o-aminophenol by chlorate

Energy Technology Data Exchange (ETDEWEB)

Hiraki, K; Shimizu, N; Nishikawa, Y [Kinki Univ., Higashi-Osaka, Osaka (Japan). Faculty of Science and Technology; Shigematsu, T

1981-12-01

The oxidation of o-aminophenol by chlorate ion takes place in acidic milieu and is catalyzed by a trace amount of vanadium (V). Vanadium (V) oxidizes o-aminophenol to 2-amino-3-phenoxazone, then the vanadium (IV) produced is reoxidized to vanadium (V) by the sodium chlorate. Further oxidation of o-aminophenol proceeds by repetition of these reactions. The oxidation product (2-amino-3-phenoxazone) gives an intense fluorescence; under optimum conditions, the fluorescence intensity is proportional to the concentration of vanadium. The most suitable concentration of o-aminophenol and sodium chlorate for the determination of vanadium (V) were found to be 0.02 M and 2 x 10/sup -4/ M, respectively. From 0.1 ppm to 5 ppm of vanadium (V) can be determined under the optimum conditions; reaction temperature 50/sup 0/C, reaction time 2 h, and at pH 2 +- 0.2. If the reaction time is increased to 3 h at 55/sup 0/C, the method may be extended from 2 ppb to 15 ppb of vanadium. Interferences of diverse ions were tested, among which Fe (III) and Mn (VII) caused positive errors, and Cr (VI), Mo (VI) negative errors if present in 40 fold w/w ratio to V (V).

Oxygen segregation and its impact on the absorption of hydrogen in vanadium; Einfluss der Sauerstoffsegregation auf die Absorption von Wasserstoff in Vanadium

Energy Technology Data Exchange (ETDEWEB)

Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

1998-12-31

The impact of the dissolved oxygen on the hydrogen absorption in vanadium was analysed with an UHV apparatus. The vanadium specimen with an oxygen content of 230 ppm was treated by a variety of heat treatments. The depth distributions of the induced concentrations of segregated oxygen in the specimen were analysed by SIMS. It was found that the amount of segregated oxygen increases with rising final temperature and tempering period. In a further experiment, the specimen was exposed after each segregation process to a H{sub 2}-pressure of 2.2 x 10{sup -4} Pa for a period of 1800 sec. The hydrogen amounts absorbed in the specimen were determined by thermal desorption mass spectrometry (TDMS). It was found that segregation of oxygen close to the surface of the specimen likewise hampers the absorption of hydrogen. (orig./CB) [Deutsch] Der Einfluss des im Volumen geloesten Sauerstoffs auf die Wasserstoff-Absorption in Vanadium wurde in einer UHV-Apparatur untersucht. Zunaechst wurde die V-Probe mit einem Sauerstoffgehalt von 230 ppm unterschiedlichen thermischen Behandlungen ausgesetzt. Die sich einstellenden Konzentrationstiefenverteilungen des an der Oberflaeche segregierten Sauerstoffs wurden anschliessend mit SIMS untersucht. Dabei nimmt die Menge des segregierten Sauerstoffs mit der Hoehe der Endtemperatur sowie der Temperzeit zu. In einem weiteren Experiment wurde die Probe nach jeder Segregationsprozedur fuer eine Zeit von 1800 sec einem H{sub 2}-Druck von 2.2 x 10{sup -4} Pa ausgesetzt. Die Mengen des dabei aufgenommenen Wasserstoffs wurden mit Hilfe der thermischen Desorptions-Massenspektrometrie TDMS bestimmt. Dabei zeigt sich, dass auch die Segregation von Sauerstoff im oberflaechennahen Bereich die Wasserstoffaufnahme in Vanadium behindert. (orig.)

Bipolar resistive switching in room temperature grown disordered vanadium oxide thin-film devices

Science.gov (United States)

Wong, Franklin J.; Sriram, Tirunelveli S.; Smith, Brian R.; Ramanathan, Shriram

2013-09-01

We demonstrate bipolar switching with high OFF/ON resistance ratios (>104) in Pt/vanadium oxide/Cu structures deposited entirely at room temperature. The SET (RESET) process occurs when negative (positive) bias is applied to the top Cu electrode. The vanadium oxide (VOx) films are amorphous and close to the vanadium pentoxide stoichiometry. We also investigated Cu/VOx/W structures, reversing the position of the Cu electrode, and found the same polarity dependence with respect to the top and bottom electrodes, which suggests that the bipolar nature is linked to the VOx layer itself. Bipolar switching can be observed at 100 °C, indicating that it not due to a temperature-induced metal-insulator transition of a vanadium dioxide second phase. We discuss how ionic drift can lead to the bipolar electrical behavior of our junctions, similar to those observed in devices based on several other defective oxides. Such low-temperature processed oxide switches could be of relevance to back-end or package integration processing schemes.

Investigation of possible application of the chromazole KS reagent to the analytical chemistry of vanadium

International Nuclear Information System (INIS)

Gordeeva, M.N.; Fedorova, L.N.; Basargin, N.N.; Rozovskij, Yu.G.

1978-01-01

Complex formation of vanadium (4) with chromazole KS has been investigated by the spectrophotometric method. It has been found that two complex compounds are formed: Me:R=1:1 (pH=4.0) and Me:R=1:2 (pH=6.2). The chemistry of the interaction of vanadium (4) with chromazole KS has been studied. A method of the photometric determination of vanadium (4) in standard steels and optical glasses has been developed

Study of propane partial oxidation on vanadium-containing catalysts

Energy Technology Data Exchange (ETDEWEB)

Komashko, G.A.; Khalamejda, S.V.; Zazhigalov, V.A. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Fizicheskoj Khimii

1998-12-31

The present results indicate that maximum selectivity to acrylic acid can be reached over V-P-Zr-O catalysts. When the hydrocarbon concentration is 5.1 vol.% the selectivity is about 30% at quite high paraffin conversion. Conclusively, some explanations to the observed facts can be given. The V-P-O catalyst promotion with lanthanum by means of mechanochemical treatment is distinguished by the additive uniform spreading all over the matrix surface. Such twophase system is highly active in propane conversion (lanthanum oxide) and further oxidation of the desired products. The similar properties are attributed to V-P-Bi-La-O catalyst. Bismuth, tellurium and zirconium additives having clearly defined acidic properties provoke the surface acidity strengthening and make easier desorption of the acidic product (acrylic acid) from the surface lowering its further oxidation. Additionally, since bismuth and zirconium are able to form phosphates and, according to, to create space limitations for the paraffin molecule movement out of the active group boundaries, this can be one more support in favour of the selectivity increase. With this point of view very interesting results were obtained. It has been shown that the more limited the size of the vanadium unit, the higher the selectivity is. Monoclinic phase AV{sub 2}P{sub 2}O{sub 10} which consists in clusters of four vanadium atoms is sensibly more reactive than the orthorhombic phase consists in V{sub {infinity}} infinite chains. (orig.)

Simple Sensitive Spectrophotometric Determination of Vanadium in Biological and Environmental Samples

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B. Krishna Priya

2006-01-01

Full Text Available Novel, rapid, highly sensitive and selective spectrophotometric method for the determination of traces of vanadium (V in environmental and biological samples, pharmaceutical and steel samples was studied. The method is based on oxidation of 2,4- dinitro phenyl hydrazine(2,4-DNPH by vanadium (V followed by coupling reaction with N-(1-naphthalene-1-ylethane-1,2-diamine-dihydrochloride (NEDA in acidic medium to give red colored derivative or on oxidation of 4-Amino Pyridine by vanadium (V followed by coupling reaction with NEDA in basic medium to give pink colored derivative. The red colored derivative having an λmax 495 nm which is stable for 8 days and the pink colored derivative with 525 nm is stable for more than 7 days at 350C. Beer's law is obeyed for vanadium (V in the concentration range of 0.02 - 3.5 μg mL–1 (red derivative and 0.03 – 4.5 μg mL–1 (pink derivative at the wave length of maximum absorption. The optimum reaction conditions and other analytical parameters were investigated to enhance the sensitivity of the present method. The detailed study of various interferences made the method more selective. The proposed method was successfully applied to the analysis of vanadium in natural water samples, plant material, soil samples, synthetic mixtures, pharmaceutical samples and biological samples. The results obtained were agreed with the reported methods at the 95 % confidence level. The performance of proposed method was evaluated in terms of Student's t-test and Variance ratio f-test which indicates the significance of proposed method over reported method.

Determination of factor of hydrogen permeation reduction (PRF) for different protective coatings over vanadium

International Nuclear Information System (INIS)

Afanasyev, S.; Kulsartov, T.; Shestakov, V.; Chikhray, Y.; Smith, D.

2002-01-01

Selection of structural materials for liquid-metal system as well as for another system and constructions of nuclear energy plants must be carried out and based on specified demands depending on conditions of these materials functioning. Specific demand is its compatibility with liquid metals. Design of reactors with liquid-metal coolant (Li, PbLi 17 ) which reproduces tritium arise additional demand to structural materials. This demand is a creation of structural material or protective barrier with minimum acceptable value of tritium permeation through itself or with maximum permeation reduction factor (PRF). Vanadium and vanadium alloys are supposed to be use as a blanket structural material in such nuclear energy plants. Worked out at first stage of studies vanadium coatings should have stability of its characteristics at temperature 800 deg. C under influence of hydrogen. Given work shows the experimental results on testing of protective coatings over vanadium: glass-ceramic coating and CaO-base coating. PRF for every coating and its changes depending on thermo-capacity of vanadium sample with coating was determined by method of hydrogen permeation. The results of experiments would be used at the development of cooling loops of reactor core protection with liquid-metal coolant

Effect of vanadium doping on structural and magnetic properties of defective nano-nickel ferrite

Science.gov (United States)

Heiba, Zein K.; Mohamed, Mohamed Bakr; Wahba, Adel Maher; Almalowi, M. I.

2018-04-01

Nano-nickel ferrites defected by vanadium doping (NiV x Fe2-1.67 x O4, 0 ≤ x ≤ 0.25) were prepared using a simple sol gel method. Rietveld analysis revealed a nonmonotonic change in lattice parameter, oxygen parameter and magnetization upon doping with vanadium. Cation distributions suggested from either Rietveld analysis or from experimental magnetic moments were in a good agreement. For low doping values ( x = 0.05), vanadium was residing mainly in octahedral sites, while for samples with vanadium content ( x ≥ 0.1) a significant part of vanadium ions resided at tetrahedral sites; a result which has been confirmed by the analysis of Fourier-transform infrared (FTIR) spectrums obtained for the samples. The transmission electron microscope (TEM) image showed fine spherical particles with size of ˜ 11 nm. All samples showed a superparamagnetic nature with a nonmonotonic change of either magnetization ( M S) or coercivity (H C) with the content of nonmagnetic V5+. The cation occupancies indicated presence of an enormous number of vacancies through doping with high valence cation V5+, making present samples potential electrodes for Li- or Na-ion batteries.

Real-time monitoring of capacity loss for vanadium redox flow battery

Science.gov (United States)

Wei, Zhongbao; Bhattarai, Arjun; Zou, Changfu; Meng, Shujuan; Lim, Tuti Mariana; Skyllas-Kazacos, Maria

2018-06-01

The long-term operation of the vanadium redox flow battery is accompanied by ion diffusion across the separator and side reactions, which can lead to electrolyte imbalance and capacity loss. The accurate online monitoring of capacity loss is therefore valuable for the reliable and efficient operation of vanadium redox flow battery system. In this paper, a model-based online monitoring method is proposed to detect capacity loss in the vanadium redox flow battery in real time. A first-order equivalent circuit model is built to capture the dynamics of the vanadium redox flow battery. The model parameters are online identified from the onboard measureable signals with the recursive least squares, in seeking to keep a high modeling accuracy and robustness under a wide range of working scenarios. Based on the online adapted model, an observer is designed with the extended Kalman Filter to keep tracking both the capacity and state of charge of the battery in real time. Experiments are conducted on a lab-scale battery system. Results suggest that the online adapted model is able to simulate the battery behavior with high accuracy. The capacity loss as well as the state of charge can be estimated accurately in a real-time manner.

Vanadium Mining and Cattle Health : Sentinel studies, epidemiological and veterinary public health issues

NARCIS (Netherlands)

Gummow, B.

2005-01-01

The thesis covers a field outbreak investigation into the cause and pathogenesis of "illthrift" on a dairy farm that was due to vanadium exposure, it examines methods of treating vanadium poisoning in cattle using an experimental study, looks at the use of cattle as sentinels for detecting and

Vanadium Doped Tungsten Oxide Material - Electrical Physical and Sensing Properties

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Shishkin N. Y.

2008-05-01

Full Text Available The electrical physical and sensing (to VOCs and inorganic gases properties of vanadium doped tungsten oxide in the regions of phase transition temperature were investigated. Vanadium oxide (II dimerization was observed in the doped material, corresponding to new phase transition. The extreme sensitivity and selectivity to chemically active gases and vapors in small concentrations: CO, NOx, NH3 acetone, ethanol near phase transitions temperature was found. Sensor elements were manufactured for the quantitative detection (close to 1 ppm of alcohol and ammonia.

Partial molar volumes of hydrogen and deuterium in niobium and vanadium

International Nuclear Information System (INIS)

Herro, H.M.

1979-01-01

Lattice dilation studies and direct pressure experiments gave comparable values for the partial molar volumes of hydrogen and deuterium in niobium and vanadium. Small isotope effects in the partial molar volume of hydrogen were measured in both metals by the differential isotope method. Hydrogen had a larger partial molar volume than deuterium in niobium, but the reverse was true in vanadium. The isotope effect measured in niobium can be represented as being due to the larger amplitude of vibration of the hydrogen atom than the deuterium atom in the metal lattice. Since hydrogen has a larger mean displacement from the equilibrium position than does deuterium, the average force hydrogen exerts on the metal atoms is greater than the force deuterium exerts. The isotope effect in vanadium is likely a result of anharmonic effects in the lattice and local vibrational modes

The oxidation of organic additives in the positive vanadium electrolyte and its effect on the performance of vanadium redox flow battery

Science.gov (United States)

Nguyen, Tam D.; Whitehead, Adam; Scherer, Günther G.; Wai, Nyunt; Oo, Moe O.; Bhattarai, Arjun; Chandra, Ghimire P.; Xu, Zhichuan J.

2016-12-01

Despite many desirable properties, the vanadium redox flow battery is limited, in the maximum operation temperature that can be continuously endured, before precipitation begins in the positive electrolyte. Many additives have been proposed to improve the thermal stability of the charged positive electrolyte. However, we have found that the apparent stability, revealed in laboratory testing, is often simply an artifact of the test method and arises from the oxidation of the additive, with corresponding partial reduction of V(V) to V(IV). This does not improve the stability of the electrolyte in an operating system. Here, we examined the oxidation of some typical organic additives with carboxyl, alcohol, and multi-functional groups, in sulfuric acid solutions containing V(V). The UV-vis measurements and titration results showed that many compounds reduced the state-of-charge (SOC) of vanadium electrolyte, for example, by 27.8, 88.5, and 81.9% with the addition of 1%wt of EDTA disodium salt, pyrogallol, and ascorbic acid, respectively. The cell cycling also indicated the effect of organic additives on the cell performance, with significant reduction in the usable charge capacity. In addition, a standard screening method for thermally stable additives was introduced, to quickly screen suitable additives for the positive vanadium electrolyte.

On the superconductivity of vanadium based alloys

International Nuclear Information System (INIS)

Brouers, F.; Rest, J. Van der

1984-01-01

The electron density of states of solid solutions of vanadium based transition metal alloys V 90 X 10 is computed with the aim of calculating the superconducting transition temperature using the McMillan formula. As observed experimentally for X on the left hand side of V in the periodic table, one obtains an increase of Tc while for X on the right hand side of V the critical temperature decreases. The detailed comparison with experiments indicate that when the bandwidths of the two constituents are different, one cannot neglect the variation of the electron-phonon interactions. Another important conclusion is that for alloys which are in the split-band limit like VAu, VPd and VPt, the agreement with experimental data can be obtained only by assuming that these alloys have a short-range order favouring clusters of pure vanadium. (Author) [pt

Determination of micro amounts of vanadium by oxidative coupling of α-naphthol and p-phenylenediamine

International Nuclear Information System (INIS)

Hainberger, S.J.; Damasceno, R.N.

1975-01-01

A sensitive determination of vanadium is described. In the presence of the necessary amount of potassium chlorate and small amounts of vanadium, α-naphthol and p-phenylenediamine react to yield a dyestuff, which exhibits an absorption maximum at 345 nm. The Lambert-Beer law is followed at 0.008-0.12 μg vanadium per ml. The molar extinction amounts to 54 x 10 4 .mol -1 The removal of the interfering cations is described. (author)

Development of cloud point extraction - UV-visible spectrophotometric method for vanadium (V) determination in hydrogeochemical samples

International Nuclear Information System (INIS)

Durani, Smeer; Mathur, Neerja; Chowdary, G.S.

2007-01-01

The cloud point extraction behavior (CPE) of vanadium (V) using 5,7 dibromo 8-hydroxyquinoline (DBHQ) and triton X 100 was investigated. Vanadium (V) was extracted with 4 ml of 0.5 mg/ml DBHQ and 6 ml of 8% (V/V) triton X 100 at the pH 3.7. A few hydrogeochemical samples were analysed for vanadium using the above method. (author)

Hydrogen in niobium, tantalum, and vanadium: Structures, phase diagrams, and morphologies

International Nuclear Information System (INIS)

Schober, T.

1978-07-01

The paper discusses basic aspects of the reactions between the metals niobium, tantalum, vanadium, and hydrogen or deuterium. After an introduction to problems of preparation experimental technqiues for the investigation of hydrides are presented. The possible hydride structures are discussed. With vanadium, there are great differences between the structures of hydrides and deuterides. Detailed mention is also made of recent measurements of the NGH, TaH, VH, and VD phase diagrams. (orig./WBU) [de

Investigation of vanadium and nitride alloys thin layers deposited by PVD

Directory of Open Access Journals (Sweden)

Nouveau C.

2012-06-01

Full Text Available In this work we present the technique of magnetron vapor deposition and the effect of several deposition parameters on the structural and morphological properties of prepared thin films. It was noted that the deposition time has an effect on the crystallinity, mechanical properties such as residual stress, roughness surface and the layer composition from target products. Studies were carried out on layers of vanadium (V and the nitride vanadium (VN.

Synthesis of nanoparticles of vanadium carbide in the ferrite of nodular cast iron

CERN Document Server

Fras, E; Guzik, E; Lopez, H

2005-01-01

The synthesis method of nanoparticles of vanadium carbide in nodular cast iron is presented. After introduction of this method, the nanoparticles with 10-70 nm of diameter was obtained in the ferrite. The diffraction investigations confirmed that these particles are vanadium carbides of type V/sub 3/C/sub 4/.

Species transport mechanisms governing capacity loss in vanadium flow batteries: Comparing Nafion® and sulfonated Radel membranes

International Nuclear Information System (INIS)

Agar, Ertan; Knehr, K.W.; Chen, D.; Hickner, M.A.; Kumbur, E.C.

2013-01-01

Highlights: • Species transport mechanisms are investigated in Nafion ® and s-Radel for VRFBs. • Unlike diffusion in Nafion ® , crossover in s-Radel is dominated by convection. • In particular, electro-osmotic convection is the dominant mode in s-Radel. • Change in direction of convection causes a lower crossover in s-Radel. • Hydraulic and electrokinetic permeability are as important as vanadium permeability. -- Abstract: In this study, a 2-D, transient vanadium redox flow battery (VRFB) model was used to investigate and compare the ion transport mechanisms responsible for vanadium crossover in Nafion ® 117 and sulfonated Radel (s-Radel) membranes. Specifically, the model was used to distinguish the relative contribution of diffusion, migration, osmotic and electro-osmotic convection to the net vanadium crossover in Nafion ® and s-Radel. Model simulations indicate that diffusion is the dominant mode of vanadium transport in Nafion ® , whereas convection dominates the vanadium transport through s-Radel due to the lower vanadium permeability, and thus diffusivity of s-Radel. Among the convective transport modes, electro-osmotic convection (i.e., electro-osmotic drag) is found to govern the species crossover in s-Radel due to its higher fixed acid concentration and corresponding free ions in the membrane. Simulations also show that vanadium crossover in s-Radel changes direction during charge and discharge due to the change in the direction of electro-osmotic convection. This reversal in the direction of crossover during charge and discharge is found to result in significantly lower “net” crossover for s-Radel when compared to Nafion ® . Comparison of these two membranes also provides guidance for minimizing crossover in VRFB systems and underscores the importance of measuring the hydraulic and the electro-kinetic permeability of a membrane in addition to vanadium diffusion characteristics, when evaluating new membranes for VRFB applications

The Vanadium Window with special reference to Joseph and James Flannery's contribution to the American steel and radium industries

International Nuclear Information System (INIS)

Lubenau, J. O.; Mould, R. F.

2008-01-01

The discovery of vanadium is described and the founding of the American Vanadium Company by Joseph Flannery (1867-1920) and its headquarters building in Pittsburgh in which was the stained glass window depicting the origin of the name Vanadium. Company orders for vanadium steel were obtained for the Panama canal and from Henry Ford. When his sister was diagnosed with cancer, Joseph Flannery withdrew from his vanadium interests and founded the Standard Chemical and Radium Chemical Companies which were the major suppliers of radium in the USA in the 1920s (before the Union Minicre du Haut Katanga commenced its commercial operations), processed from American mined carnotite in Colorado and Utah. Significant contributions to these enterprises involving vanadium and radium were also made by Joseph's elder brother, James Flannery (1848-1920). (author)

Optical and electrochromic properties of sol-gel deposited Ti- doped vanadium oxide films

International Nuclear Information System (INIS)

Oezer, N.; Sabuncu, S.

1997-01-01

Because of the yellowish color, vanadium oxide films in the as deposited state is not as favorable as transparent coatings for most elector chromic devices. an interesting possibility to alter the yellowish colours is the doping with other non-absorbing metal oxides. Ti doped vanadium oxide films with various amounts of titanium were synthesized and investigated as transparent counter electrodes for electrochromic transmissive device application. Electrochromic titanium doped vanadium pentoxide (V sub 2 O 5) coatings were prepared by the sol-gel dip coating technique. The coating solutions were synthesized from vanadium tri(isopropoxide) precursors. X-ray diffraction (XRD) studies showed that the sol-gel deposited doped films heat treated at temperatures below 350 degree centigrade, were amorphous, whereas hose heat treated at higher temperatures were slight y crystalline. The optical and electrochemical properties of the Ti doped vanadium oxide films has been investigated in 0.1 m LiClO sub 4 propylene carbonate solution color changes by dropping were noted for all investigated films exhibits good electrochemical cycling (CV) measurements also showed that Ti doped V sub 2 O sub 5 films exhibits good electrochemical cycling reversibility, 'in situ' optical measurement revealed that those films exhibits good electrochemical cycling the spectra range 300 < lambda < 800 nm and change color between yellow and light green. The change in visible transmittance was 25 % for 5% Ti doped film. (author)

Particle fracture and plastic deformation in vanadium pentoxide

Indian Academy of Sciences (India)

Particle fracture and plastic deformation in vanadium pentoxide powders induced by high energy vibrational ball-mill ... Keywords. X-ray diffraction; ball-milling; plastic deformation; microstrain. ... Bulletin of Materials Science | News.

Thermodynamic considerations for the use of vanadium alloys with ceramic breeder materials

International Nuclear Information System (INIS)

Johnson, C.E.; Johnson, I.; Kopasz, J.P.

1995-01-01

Fusion energy is considered to be an attractive energy form because of its minimal environmental impact. In order to maintain this favorable status, every effort needs to be made to use low activation materials wherever possible. The tritium breeder blanket is a focal point of system design engineers who must design environmentally attractive blankets through the use of low activation materials. Of the several candidate lithium-containing ceramics being considered for use in the breeder blanket, Li 2 O, Li 2 TiO 3 , are attractive choices because of their low activation. Also, low activation materials like the vanadium alloys are being considered for use as structural materials in the blanket. The suitability of vanadium alloys for containment of lithium ceramics is the subject of this study. Thermodynamic evaluations are being used to estimate the compatibility and stability of candidate ceramic breeder materials (Li 2 O, Li 2 TiO 3 , and Li 2 ZrO 3 ) with vanadium and vanadium alloys. This thermodynamic evaluation will focus first on solid-solid interactions. As a tritium breeding blanket will use a purge gas for tritium recovery, gas-solid systems will also receive attention

Effect of vanadium application on the paddy rice

Energy Technology Data Exchange (ETDEWEB)

Chiu, T F

1953-01-01

The height, the root length and the weight of rice seedlings were increased by the application of ammonium vanadate. The nitrogen contents of seedlings were generally increased in proportion to the amounts of vanadate applied. Carbon contents of seedlings, however, show little difference. The best result was obtained when V/sub 2/O/sub 3/ 150 ppm was applied, but more than 500 ppm was toxic to rice seedlings, and at 1000 ppm all rice seedlings were killed. N, P, and K fertilizers were added to the rice after transplantation from the nursery, but vanadium was omitted. Little difference was found in growth and yield of the rice plants. Vanadium absorbed by younger rice seedlings has little influence on the latter growth and yields of rice plants.

Improved activation cross sections for vanadium and titanium

International Nuclear Information System (INIS)

Muir, D.W.; Arthur, E.D.

1983-01-01

Vanadium alloys such as V-20Ti and V-Cr-Ti are attractive candidates for use as structural materials in fusion-reactor blankets. The virtual absence of long-lived activation products in these alloys suggest the possibility of reprocessing on an intermediate time scale. We have employed the modern Hauser-Feshbach nuclear-model code GNASH to calculate cross sections for neutron-activation reactions in 50 V and 51 V, to allow a more accurate assessment of induced radioactivity in vanadium alloys. In addition, cross sections are calculated for the reactions 46 Ti(n,2n) and 45 Ti(n,2n) in order to estimate the production of 44 Ti, a 1.2-MeV gamma-ray source with a half-life of 47 years

The electrical properties of semiconducting vanadium phosphate glasses

International Nuclear Information System (INIS)

Moridi, G.R.; Hogarth, C.A.; Hekmat Shooar, N.H.

1984-01-01

Vanadium phosphate glasses are a group of oxide glasses which show the semiconducting behaviour. In contrast to the conventional glasses, the conduction mechanism in these glasses is electronic, rather than being ionic. Since 1954, when the first paper appeared on the semiconducting properties of these glasses, much work has been carried out on transition-metal-oxide glasses in general, and vanadium phosphate glasses in particular. The mechanism of conduction is basicaly due to the transport of electrons between the transition-metal ions in different valency states. In the present paper, we have reviewed the previous works on the electrical characteristics of P 2 O 5 -V 2 O 5 glasses and also discussed the current theoretical ideas relevant for the interpretation of the experimental data

Work function in niobium, tantalum and vanadium hydrides

International Nuclear Information System (INIS)

Kucherov, Ya.R.; Markin, V.Ya.; Savin, V.I.; Topil'skij, N.D.

1978-01-01

The concentration dependences of the work function of electrons in hydrides of Nb, Ta and V are presented. The work function of electrons was studied at room temperature by the contact Kelvin potential difference method to an accuracy of +-0.02 eV. The effect of hydrogen on the work function variations in the systems investigated has been analyzed. It is shown that a higher hydrogen concentration in solid solutions based on the Nb-H and Ta-H systems increases the effective total positive dipole moment, whereby the work function decreases. The abnormal changes in the work function in the region of solid solutions of hydrogen in vanadium seem to be due to the specific electronic structure of vanadium and its interaction with hydrogen

Determination of vanadium in high grade carbons by radioanalytical methods

International Nuclear Information System (INIS)

Jinno, K.; Sato, M.; Amemiya, S.; Katoh, T.

1980-01-01

The present work deals with the determination of vanadium in high grade carbons by three radioanalytical methods, viz. thermal neutron activation analysis with an accelerator, thermal neutron activation analysis with a reactor and proton induced X-ray emission analysis with an accelerator. It is shown that thermal neutron activation with an accelerator is more convenient for the rapid and non-destructive analysis of ppm-level vanadium in bulk carbons than thermal neutron activation analysis with a reactor. Proton-induced X-ray emission is less useful for the analysis of bulk samples. (author)

One-step hydrothermal synthesis of hexangular starfruit-like vanadium oxide for high power aqueous supercapacitors

Science.gov (United States)

Shao, Jie; Li, Xinyong; Qu, Qunting; Zheng, Honghe

2012-12-01

Homogenous hexangular starfruit-like vanadium oxide was prepared for the first time by a one-step hydrothermal method. The assembly process of hexangular starfruit-like structure was observed from TEM images. The electrochemical performance of starfruit-like vanadium oxide was examined by cyclic voltammetry and galvanostatic charge/discharge. The obtained starfruit-like vanadium oxide exhibits a high power capability (19 Wh kg-1 at the specific power of 3.4 kW kg-1) and good cycling stability for supercapacitors application.

EFFECT OF VANADIUM ON THE DEACTIVATION OF FCC CATALYSTS

Directory of Open Access Journals (Sweden)

Roncolatto R.E

1998-01-01

Full Text Available This work provides concrete evidence that vanadium causes the destruction of the zeolite in the FCC catalysts by a mechanism of acid attack or solid-solid transformation, as well as additional dealumination of the zeolite framework in the presence of steam and at high temperature. While these effects resulted in the reduction in crystallinity (zeolite Y content, specific area and unit cell size of the Y zeolite as the amount of vanadium in the catalysts increased, the reduction in activity was the most pronounced. The differences in these behaviors were interpreted and the model can be used for better catalyst formulation or screening.

Preliminary studies of vanadium-base alloys intended for use in fabrication of cans for fast reactors; Etudes preliminaires sur les alliages a base de vanadium envisages pour la fabrication de gaines de reacteurs rapides

Energy Technology Data Exchange (ETDEWEB)

Conte, M [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1967-03-15

Preliminary research has been carried out on a series of vanadium-based alloys: V, 0.5 per cent Si; V, 5 per cent Ca; V, 5 per cent Mo; V, 5 per cent Nb; V, 2 per cent Zr; V, 20 per cent Ti; V, 10 per cent Al; V, 10 per cent Sn and v, 10 per cent Ti liable to be used as canning material in fast reactors. The transformation by forging at about 1000 deg. C and rolling between 200 deg. C and room temperature is satisfactory for all types of alloys except V with 10 per cent Sn and V with 10 per cent Al. The mechanical properties deduced from tensile strength tests carried out on alloy samples annealed 1 hour at 1050 deg. C in a vacuum show that, generally speaking, the addition elements lead to an improvement in these properties as compared to those of pure vanadium. After undergoing corrosion tests in a liquid sodium loop purified by a cold trap, the alloys become brittle at room temperature. Only the vanadium containing 20 per cent Ti keeps its plastic properties. These alloys are covered by a layer of vanadium carbide VC. After undergoing treatment in a liquid sodium loop purified by a hot trap, all the alloys keep their good mechanical characteristics. The surface layer with which they are covered is composed of two vanadium carbides VC and {sub {gamma}}VC, and a vanadium sub-oxide VO{sub 0.9}. (author) [French] Des etudes preliminaires ont ete faites sur une serie d'alliages a base de vanadium: V-0,5 pour cent Si, V-5 pour cent Ca, V-5 pour cent Mo, V-5 pour cent Nb, V-2 pour cent Zr, V-20 pour cent Ti, V-10 pour cent Al, V-10 pour cent Sn et V-10 pour cent Ti susceptibles d'etre utilises comme materiau de gainage pour les reacteurs rapides. La transformation par forgeage a 1000 deg. C environ et laminage entre 200 deg. C et la temperature ambiante est satisfaisante pour toutes les nuances d'alliage sauf le V-10 pour cent Sn et le V-10 pour cent Al. Les proprietes mecaniques deduites des essais de traction realises sur des eprouvettes d'alliages recuits 1 heure a

On change of vanadium carbide state during 20Kh3MVF steel heat treatment

International Nuclear Information System (INIS)

Gitgarts, M.I.; Maksimenko, V.N.

1975-01-01

The Xray diffraction study of vanadium carbide MC has been made in the steel-20KH3MVF quenched from 970 and 1040 deg and tempered at 660 deg for 210 hrs. It has been found that the constant of the MC crystal lattice regularly varies with the temperature of isothermal hold-up. In the steel tempered after quenching two vanadium carbides of different content could co-exist simultaneously: carbide formed in the quenching process and carbide formed during tempering. The discovered effect of the temperature dependence of the MC content is, evidently, inherent also to other steels containing vanadium

Determination of trace vanadium using its catalytic effect on the oxidation of gallic acid by bromate

International Nuclear Information System (INIS)

Yamane, Takeshi; Fukasawa, Tsutomu

1976-01-01

The oxidation of gallic acid by bromate with trace vanadium as catalyst was followed spectrophotometrically by measurements of absorbance change at 420 nm. The reaction rate was obtained graphically from the absorbance vs. time curve in the range of about 15 to 40 min. reaction time. The reaction rate was proportional to the concentration of vanadium(V) in the range 0--120 ng (under the conditions of 5.3x10 -3 M gallic acid, 6.0x10 -3 M potassium bromate, pH 3.8) and 0--30 ng (1.1x10 -2 M gallic acid, 2.7x10 -2 M potassium bromate, pH 3.8). Using this relationship, the concentration of vanadium as low as 0.1 ng/ml can be determined. The relative standard deviations at 50 ng and 20 ng of vanadium were 3.5% (n=14) and 4.0% (n=10), respectively. Iron(III) interfered seriously even when present in 20 times the amounts of vanadium. Up to 60 times, W(VI), Mo(VI) and iodide did not interfere. Many of the other ions examined were found to have no effect or slight effect even when present in 1000 times the amounts of vanadium. Other factors affecting the reaction rate were also studied. (auth.)

Annealing of neutron-irradiated vanadium containing oxygen

International Nuclear Information System (INIS)

Foster, R.E.

1979-01-01

A study to clarify the role of interstitial oxygen in irradiated vanadium by measuring the activation energy of the 0.2 T/sub m/ recovery stage in well-characterized samples, where T/sub m/ is the melting temperature in degrees Kelvin, is described

Novel Vanadium-Loaded Ordered Collagen Scaffold Promotes Osteochondral Differentiation of Bone Marrow Progenitor Cells

Directory of Open Access Journals (Sweden)

Ana M. Cortizo

2016-01-01

Full Text Available Bone and cartilage regeneration can be improved by designing a functionalized biomaterial that includes bioactive drugs in a biocompatible and biodegradable scaffold. Based on our previous studies, we designed a vanadium-loaded collagen scaffold for osteochondral tissue engineering. Collagen-vanadium loaded scaffolds were characterized by SEM, FTIR, and permeability studies. Rat bone marrow progenitor cells were plated on collagen or vanadium-loaded membranes to evaluate differences in cell attachment, growth and osteogenic or chondrocytic differentiation. The potential cytotoxicity of the scaffolds was assessed by the MTT assay and by evaluation of morphological changes in cultured RAW 264.7 macrophages. Our results show that loading of VOAsc did not alter the grooved ordered structure of the collagen membrane although it increased membrane permeability, suggesting a more open structure. The VOAsc was released to the media, suggesting diffusion-controlled drug release. Vanadium-loaded membranes proved to be a better substratum than C0 for all evaluated aspects of BMPC biocompatibility (adhesion, growth, and osteoblastic and chondrocytic differentiation. In addition, there was no detectable effect of collagen or vanadium-loaded scaffolds on macrophage viability or cytotoxicity. Based on these findings, we have developed a new ordered collagen scaffold loaded with VOAsc that shows potential for osteochondral tissue engineering.

Pre-Concentration of Vanadium from Stone Coal by Gravity Using Fine Mineral Spiral

Directory of Open Access Journals (Sweden)

Xin Liu

2016-08-01

Full Text Available Due to the low grade of V2O5 in stone coal, the existing vanadium extraction technologies face challenges in terms of large handling capacity, high acid consumption and production cost. The pre-concentration of vanadium from stone coal before the extraction process is an effective method to reduce cost. In this study, detailed mineral characterization of stone coal was investigated. It has been confirmed that the vanadium mainly occurs in muscovite and illite. A significant demand for an effective pre-concentration process with simple manipulation for discarding quartz and other gangue minerals is expected. Based on the mineralogical study, a new vanadium pre-concentration process using a fine mineral spiral was investigated. The experimental results showed that the separation process, which was comprised of a rougher and scavenger, could efficiently discard quartz, pyrite and apatite. A final concentrate with V2O5 grade of 1.02% and recovery of 89.6% could be obtained, with 26.9% of the raw ore being discarded as final tailings.

Partial Oxidation of n-Butane over a Sol-Gel Prepared Vanadium Phosphorous Oxide

Directory of Open Access Journals (Sweden)

Juan M. Salazar

2013-01-01

Full Text Available Vanadium phosphorous oxide (VPO is traditionally manufactured from solid vanadium oxides by synthesizing VOHPO4∙0.5H2O (the precursor followed by in situ activation to produce (VO2P2O7 (the active phase. This paper discusses an alternative synthesis method based on sol-gel techniques. Vanadium (V triisopropoxide oxide was reacted with ortho-phosphoric acid in an aprotic solvent. The products were dried at high pressure in an autoclave with a controlled excess of solvent. This procedure produced a gel of VOPO4 with interlayer entrapped molecules. The surface area of the obtained materials was between 50 and 120 m2/g. Alcohol produced by the alkoxide hydrolysis reduced the vanadium during the drying step, thus VOPO4 was converted to the precursor. This procedure yielded non-agglomerated platelets, which were dehydrated and evaluated in a butane-air mixture. Catalysts were significantly more selective than the traditionally prepared materials with similar intrinsic activity. It is suggested that the small crystallite size obtained increased their selectivity towards maleic anhydride.

Electrodeposition of Vanadium Oxides at Room Temperature as Cathodes in Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Michalis Rasoulis

2017-07-01

Full Text Available Electrodeposition of vanadium pentoxide coatings was performed at room temperature and a short growth period of 15 min based on an alkaline solution of methanol and vanadyl (III acetyl acetonate. All samples were characterized by X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The current density and electrolyte concentration were found to affect the characteristics of the as-grown coatings presenting enhanced crystallinity and porous structure at the highest values employed in both cases. The as-grown vanadium pentoxide at current density of 1.3 mA·cm−2 and electrolyte concentration of 0.5 M indicated the easiest charge transfer of Li+ across the vanadium pentoxide/electrolyte interface presenting a specific discharge capacity of 417 mAh·g−1, excellent capacitance retention of 95%, and coulombic efficiency of 94% after 1000 continuous Li+ intercalation/deintercalation scans. One may then suggest that this route is promising to prepare large area vanadium pentoxide electrodes with excellent stability and efficiency at very mild conditions.

Influence of titanium and vanadium on the hydrogen transport through amorphous alumina films

Energy Technology Data Exchange (ETDEWEB)

Palsson, G.K. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Wang, Y.T. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Azofeifa, D. [Centro de Investigacion en Ciencia e Ingenieria de Materiales and Escuela de Fisica, Universidad de Costa Rica, San Jose (Costa Rica); Raanaei, H. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden); Department of Physics, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Sahlberg, M. [Department of Materials Chemistry, Uppsala University, Box 538, S-751 21 Uppsala (Sweden); Hjoervarsson, B. [Department of Physics, Uppsala University, Box 530, S-751 21 Uppsala (Sweden)

2010-04-02

The influence of titanium and vanadium on the hydrogen transport rate through thin amorphous alumina films is addressed. Only small changes in the transport rate are observed when the Al{sub 2}O{sub 3} are covered with titanium or vanadium. This is in stark contrast to results with a Pd overlayer, which enhances the transport by an order of magnitude. Similarly, when titanium is embedded into the alumina the transport rate is faster than for the covered case but still slower than the undoped reference. Embedding vanadium in the alumina does not yield an increase in uptake rate compared to the vanadium covered oxide layers. These results add to the understanding of the hydrogen uptake of oxidized metals, especially the alanates, where the addition of titanium has been found to significantly enhance the rate of hydrogen uptake. The current findings eliminate two possible routes for the catalysis of alanates by Ti, namely dissociation and effective diffusion short-cuts formed by Ti. Finally, no photocatalytic enhancement was noticed on the titanium covered samples.

Enhancing the Electronic Conductivity of Vanadium-tellurite Glasses by Tuning the Redox State

DEFF Research Database (Denmark)

Kjeldsen, Jonas; Yue, Yuanzheng

Transition metal oxides are used in a variety of electronic purposes, e.g., vanadium tellurite as cathode material in high-power demanding batteries. By tuning the redox state of vanadium, it is possible to achieve a lower internal resistance within the entire battery unit, thus a higher capacity....... In this work we vary the redox state of a given vanadium tellurite system by performing post heat-treatment in controlled atmosphere. This process is in theory not limited only to varying electronic conductivity, but also varying the glass structure, and hence, changing properties of the glasses, e.g, thermal...... and mechanical properties. Finally we give insight into the relation between the redox state and electronic conductivity....

Electronic properties and reactivity of vanadium complexes of bipyridine and cyanometallates

International Nuclear Information System (INIS)

Lellis, F.T.P.

1988-01-01

This work deals with the chemistry of two types of vanadium compounds. The first one consists of polymeric pigments containing vanadium (III) ions and hexacyanoferrate (II) or substituted pentacyanoferrate (II) complexes. A series of 14 complexes were isolated in solid state, exhibiting the following composition V sub(4) [ Fe (CN) sub(4) ]. 16H sub(2)O or V [ Fe (CN) sub(5) L ]. 4H sub(2)O (L imidazole, pyridine and pyrazine derivatives). These complexes exhibit strong absorption bands in the visible-uv region, ascribed to intervalence transfer transitions. The infrared spectra were assigned, showing a linear correlation of the CN stretching frequencies with the sup(13)C NMR chemical shifts of the cyanide ligands in the complexes. The second system which has been investigated consists of a series of substituted species with vanadium (II) and (III) ions with 2,2 bypyridine ligands, formulated as [V (bipy) 3 - n (H sub(2)O) 6-2n ] sup(2+) and [ Cl (bipy)nVOV(bipy)nCl] sup(4)+ (n= 1-3) respectively. The electronic spectra of these complexes were assigned in parallel with magnetic and vibrational studies. Resonance Raman spectra of the vanadium (II) complexes exhibited strong enhancement of the bipyridine vibrational modes. In contrast, the vibrational modes of the V (III)-O-V(III) chromophore were preferentialy enhanced in the dimeric species. (author)

Self-assembling Synthesis of Vanadium Oxide Nanotubes and Simple Determination of the Content of Ⅴ(Ⅳ)

Institute of Scientific and Technical Information of China (English)

MAI Li-qiang; CHEN Wen; XU Qing; ZHU Quan-yao; HAN Chun-hua; PENG Jun-feng

2003-01-01

High-yielding low-cost vanadium oxide nanotubes were prepared by the hydrothermal self-assembling process from vanadium pentoxide and organic molecules as structure-directing templates. Moreover, a new method was discovered for determining the content of V (Ⅳ) in vanadium oxide nanotubes by thermogravimetric analysis ( TGA ). This method is simple, precise and feasible and can be extended to determine the content of low oxidation state in the other transition metal oxide nanomaterials.

Performance Modeling of a Vanadium Redox Flow Battery during Discharging

International Nuclear Information System (INIS)

Yang, W.W.; He, Y.L.; Li, Y.S.

2015-01-01

A two-dimensional quasi-steady-state model is presented to simulate coupled mass-species-charge transfer and electrochemical reactions in all vanadium redox flow battery. Emphasis is located on examining the influences of applied current density, initial vanadium concentration, initial acid concentration and electrolyte flow rate on overpotentials in both electrodes, ohmic loss in electrolyte phase as well as battery discharging voltage. It is indicated that overpotential in negative electrode is the dominant factor causing the loss of battery discharging voltage at relatively lower or higher state of charge, while ohmic loss in electrolyte phase is dominant when discharging at moderate state of charge. Increasing initial vanadium concentration, the battery discharging voltage is significantly increased due to the reduced overpotentials in both electrodes. With the increase in initial acid concentration, the battery discharging voltage is also obviously increased because of increased open circuit voltage and decreased ohmic loss in electrolyte phase. As the electrolyte flow rate increases, the total discharging time is extended due to the retarded concentration polarization and the battery discharging voltage is obviously increased at lower state of charge

Determination of vanadium in sea water by graphite furnace atomic absorption spectrometry with a tube coated with pyrolytic graphite

International Nuclear Information System (INIS)

Shimizu, Tokuo; Sakai, Kaoru

1981-01-01

The trace amount of vanadium in sea water was determined by graphite furnace atomic absorption spectrometry with a tube coated with pyrolytic graphite. To correct the background absorption, a deuterium lamp with a higher-brilliant thermal cathode was used. The sensitivity for vanadium increased 10 -- 20 fold by the use of the tube coated with pyrolytic graphite, and the utility lifetime of the tube was greatly extended. Vanadium(V) - 4-(2-pyridylazo)resorcinol (PAR) complexes were extracted into chloroform as an ion-pair with benzyldimethyltetradecylammonium (Zephiramine) cation alternatively. The sample of sea water, which was made to 0.1 N in sulfuric acid and 0.1% in hydrogen peroxide, was loaded onto the column of Dowex 1-X 4 resin (SO 4 2- -form). Vanadium was then eluted from the resin with 1 N sulfuric acid-0.1% hydrogen peroxide or 1 N hydrochloric acid-0.1% hydrogen peroxide evaporated to dry. After dissolution of the elute in 0.2 N nitric acid, vanadium was extracted. Secondly, the sample of sea water was adjusted to pH 5.0, and loaded onto the column of Chelex-100 resin. Vanadium was eluted from the resin with 2 N ammonia. The above two methods took much time, but the coprecipitation method was not so and recommended for the determination of vanadium in sea water. Vanadium was coprecipitated with iron(III) hydroxide-hydrous titanium(IV) oxide at pH 6.0. The precipitate was digested with nitric acid-hydrogen peroxide. The solution was diluted to 50 ml with water. The resulting solutions were employed to determine the vanadium concentration by the graphite furnace atomic absorption measurement. The trace amounts of vanadium in various kinds of the coastal sea water were determined by the coprecipitation method. (author)

Determination of Leachable Vanadium (V) in Sediment

African Journals Online (AJOL)

NICO

KEYWORDS. Certified reference materials, vanadium(+5) speciation, electrothermal atomic absorption spectrometry. 1. Introduction. The measurement of the chemical species of elements, instead of the total element concentration, has become an irreversible trend in analytical chemistry.1–2 The motivation lies in the fact.

Synthesis and characterization of new vanadium salcylaldoxime ...

African Journals Online (AJOL)

ilyasblk

The elemental microanalysis and mass spectra (electrospray method) were carried out ... The 51V NMR spectra were measured in D2O or in DMSO-d6, using VOCl as the .... These signals are in the range reported for the vanadium atoms in a ...

Structural and thermal properties of vanadium tellurite glasses

Science.gov (United States)

Kaur, Rajinder; Kaur, Ramandeep; Khanna, Atul; González, Fernando

2018-04-01

V2O5-TeO2 glasses containing 10 to 50 mol% V2O5 were prepared by melt quenching and characterized by X-ray diffraction (XRD), density, Differential Scanning Calorimetry (DSC) and Raman studies.XRD confirmed the amorphous nature of vanadium tellurite samples. The density of the glasses decreases and the molar volume increases on increasing the concentration of V2O5. The thermal properties, such as glass transition temperature Tg, crystallization temperature Tc, and the melting temperature Tm were measured. Tg decreases from a value of 288°C to 232°C. The changes in Tg were correlated with the number of bonds per unit volume, and the average stretching force constant. Raman spectra were used to elucidate the short-range structure of vanadium tellurite glasses.

Analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates

Energy Technology Data Exchange (ETDEWEB)

Gautier, Romain [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France); Centre Nationale de la Recherche Scientifique (CNRS), Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes (France); Fourre, Yoann; Furet, Eric; Gautier, Regis; Le Fur, Eric [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France)

2015-04-15

An approach is presented that enables the analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates. A comparison of previously reported vanadium phosphates reveals two modes of intercalation: (i) 3d transition metal ions intercalated between VOPO{sub 4} layers and (ii) alkali/alkaline earth metal ions between VOPO{sub 4}.H{sub 2}O layers. Both intercalations were investigated using DFT calculations in order to understand the relative shifts of the vanadium phosphate layers. These calculations in addition to an analysis of the stacking sequences in previously reported materials enable the prediction of the crystal structures of M{sub x}(VOPO{sub 4}).yH{sub 2}O (M = Cs{sup +}, Cd{sup 2+} and Sn{sup 2+}). Experimental realization and structural determination of Cd(VOPO{sub 4}){sub 2}.4H{sub 2}O by single-crystal X-ray diffraction confirmed the predicted stacking sequences. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Intercalation compounds of vanadium pentoxide hydrated with metalporphyrins and lanthanide ions

International Nuclear Information System (INIS)

Oliveira, Herenilton Paulino

1994-01-01

The lamellar structure of the vanadium pentoxide matrix allows the intercalation of organic molecules, ions and conductor polymers. It is important to emphasize that the vanadium oxide matrix is an intrinsic semiconductor and presents electrochromic properties. In the beginning of this work the method of synthesis and the electrochemical and electrochromic properties were extensively explored. The effect of alkaline metal and lanthanide ions on the structure of vanadium oxide matrix was studied by X-ray and infrared spectroscopy. Moreover, the influence of those ions in the electrochemical, spectro electrochemical and magnetic properties were studied. Finally, some intercalation compounds containing porphyrins were prepared and characterized by elemental analysis, X-ray diffraction, and electronic, vibrational, Moessbauer and X-ray fluorescence spectroscopy. The electrochemical and spectro electrochemical properties were investigated. And the performance of an iron porphyrin based intercalation compound as catalyst for molecular oxygen reduction was evaluated using the rotating ring-disc electrode technique. (author)

Sulfonated graphene oxide/nafion composite membrane for vanadium redox flow battery.

Science.gov (United States)

Kim, Byung Guk; Han, Tae Hee; Cho, Chang Gi

2014-12-01

Nafion is the most frequently used as the membrane material due to its good proton conductivity, and excellent chemical and mechanical stabilities. But it is known to have poor barrier property due to its well-developed water channels. In order to overcome this drawback, graphene oxide (GO) derivatives were introduced for Nafion composite membranes. Sulfonated graphene oxide (sGO) was prepared from GO. Both sGO and GO were treated each with phenyl isocyanate and transformed into corresponding isGO and iGO in order to promote miscibility with Nafion. Then composite membranes were obtained, and the adaptability as a membrane for vanadium redox flow battery (VRFB) was investigated in terms of proton conductivity and vanadium permeability. Compared to a pristine Nafion, proton conductivities of both isGO/Nafion and iGO/Nafion membranes showed less temperature sensitivity. Both membranes also showed quite lower vanadium permeability at room temperature. Selectivity of the membrane was the highest for isGO/Nafion and the lowest for the pristine Nafion.

Effect of vanadium on plant growth and its accumulation in plant tissues

Directory of Open Access Journals (Sweden)

Narumol Vachirapatama

2011-06-01

Full Text Available Hydroponic experiments were conducted to investigate vanadium uptake by Chinese green mustard and tomato plantsand its effect on their growth. Twenty-eight (Chinese green mustard and 79 days (tomato after germination, the plants wereexposed for a further seven days to a solution containing six different concentrations of ammonium metavanadate (0-80 mg/lNH4VO3. The vanadium accumulated in the plant tissues were determined by ion-interaction high performance liquid chromatography,with confirmation by magnetic sector ICP-MS.The results indicated that nutrient solution containing more than 40 mg/l NH4VO3 affected plant growth for bothChinese green mustard and tomato plant. Chinese green mustard grown in the solution containing NH4VO3 at the concentrationsof 40 and 80 mg/l had stem length, number of leaves, dry weight of leaf, stem and root significantly lower than those ofplants grown in the solution containing 0-20 mg/l NH4VO3. Tomato plants were observed to wilt after four days in contactwith the nutrient solutions containing 40 and 80 mg/l NH4VO3. As the vanadium concentrations increased, a resultantdecrease in the stem length, root fresh weight, and fruit fresh weight were noted. The accumulation of vanadium was higher inthe root compared with leaf, stem, or fruit. Measured levels of vanadium, from a nutrient solution containing 40 mg/l NH4VO3,were 328, 340, and 9.66x103 g/g in the leaf, stem and root for Chinese green mustard, and 4.04 and 4.01x103 g/g in the fruitand roots for tomato plants, respectively.

Study of sulfur and vanadium in heavy petroleum products

Energy Technology Data Exchange (ETDEWEB)

Novelli, J.M.

1982-10-01

Sulfur compounds in heavy oil fractions (>450/sup 0/C) are studied in the first part of this work. After chemical oxidation by metachloroperbenzoic acid to obtain sulfones, sulfur compounds are analyzed by infrared spectroscopy for their qualitative and quantitative repartition. The method can be applied for the study of sulfur containing molecules before and after structural modifications of petroleum fractions by any chemical refining processes. In a second part vanadium is characterized in asphalt by physicochemical and chemical methods. 80% of the vanadium in a Boscan asphalt is under the form of porphyrins. Different associations are evidenced in petroleum fractions and metalloporphyrins, but the liaison between the vanadyl group and heterocondensate from asphalts is the more frequent.

Studies in transition metal chemistry ; V. Soluble Ziegler-type catalysts based on vanadium, part 1

NARCIS (Netherlands)

Liefde Meijer, H.J. de; Hurk, J.W.G. van den; Kerk, G.J.M. van der

1966-01-01

Experiments are described aiming at a simplification of the catalyst system originally consisting of a mixture of tetraphenyltin, aluminium bromide and vanadium tetrachloride (or vanadium oxytrichloride). It is shown that tetraphenyltin merely acts as a phenylating agent for the aluminium bromide

In situ self-sacrificed template synthesis of vanadium nitride/nitrogen-doped graphene nanocomposites for electrochemical capacitors.

Science.gov (United States)

Liu, Hong-Hui; Zhang, Hong-Ling; Xu, Hong-Bin; Lou, Tai-Ping; Sui, Zhi-Tong; Zhang, Yi

2018-03-15

Vanadium nitride and graphene have been widely used as pseudo-capacitive and electric double-layer capacitor electrode materials for electrochemical capacitors, respectively. However, the poor cycling stability of vanadium nitride and the low capacitance of graphene impeded their practical applications. Herein, we demonstrated an in situ self-sacrificed template method for the synthesis of vanadium nitride/nitrogen-doped graphene (VN/NGr) nanocomposites by the pyrolysis of a mixture of dicyandiamide, glucose, and NH 4 VO 3 . Vanadium nitride nanoparticles of the size in the range of 2 to 7 nm were uniformly embedded into the nitrogen-doped graphene skeleton. Furthermore, the VN/NGr nanocomposites with a high specific surface area and pore volume showed a high specific capacitance of 255 F g -1 at 10 mV s -1 , and an excellent cycling stability (94% capacitance retention after 2000 cycles). The excellent capacitive properties were ascribed to the excellent conductivity of nitrogen-doped graphene, high surface area, high pore volume, and the synergistic effect between vanadium nitride and nitrogen-doped graphene.

Thermodynamic considerations for the use of vanadium alloys with ceramic breeder materials

Energy Technology Data Exchange (ETDEWEB)

Johnson, C.E.; Johnson, I.; Kopasz, J.P.

1995-12-31

Fusion energy is considered to be an attractive energy form because of its minimal environmental impact. In order to maintain this favorable status, every effort needs to be made to use low activation materials wherever possible. The tritium breeder blanket is a focal point of system design engineers who must design environmentally attractive blankets through the use of low activation materials. Of the several candidate lithium-containing ceramics being considered for use in the breeder blanket, Li{sub 2}O, Li{sub 2}TiO{sub 3}, are attractive choices because of their low activation. Also, low activation materials like the vanadium alloys are being considered for use as structural materials in the blanket. The suitability of vanadium alloys for containment of lithium ceramics is the subject of this study. Thermodynamic evaluations are being used to estimate the compatibility and stability of candidate ceramic breeder materials (Li{sub 2}O, Li{sub 2}TiO{sub 3}, and Li{sub 2}ZrO{sub 3}) with vanadium and vanadium alloys. This thermodynamic evaluation will focus first on solid-solid interactions. As a tritium breeding blanket will use a purge gas for tritium recovery, gas-solid systems will also receive attention.

Coulter dispersant as positive electrolyte additive for the vanadium redox flow battery

International Nuclear Information System (INIS)

Chang Fang; Hu Changwei; Liu Xiaojiang; Liu Lian; Zhang Jianwen

2012-01-01

Coulter dispersants were investigated as the additive into the positive electrolyte (more than 1.8 M vanadium ions) of vanadium redox flow battery (VRB). The electrolyte stability tests showed that, at 45, 50 and 60 °C, the addition of 0.050–0.10 w/w Coulter dispersant IIIA (mainly containing coconut oil amine adduct with 15 ethylene oxide groups) into the positive electrolyte of VRB could significantly delay the time of precipitate formation from 1.8–12.3 h to 30.3 h ∼ 19.3 days. Moreover, the trace amount of Coulter dispersant IIIA as the additive can enhance the electrolyte stability without changing the valence state of vanadium ions, reducing the reversibility of the redox reactions and incurring other side reactions at the electrode. Using the Coulter IIIA dispersant as the additive also improved the energy efficiency of the VRB. The UV–vis spectra confirmed that the trace amount of Coulter IIIA dispersant did not chemically react with V(V) to form new substances. The synergy of Coulombic repulsion and steric hindrance between the macromolecular cationic surfactant additive and the solution reduced the aggregation of vanadium ions into V 2 O 5 and increased the supersaturation of V 2 O 5 crystal in the solution.

Vanadium extraction by combined process of lixiviation and toasting

International Nuclear Information System (INIS)

Coral, Aldo

1992-01-01

Combinated toasting and leaching processes were applied at laboratory level to vanadiferous ore from Puyango deposit in order to evaluate different rates. Before leaching, a pretreatment consisting in toasting at open atmosphere was given to the ore. Both raw and toasted ore were later washed in organic solvents. In reason of mineralogical and petrographic characteristics of the ore, only alcaline leaching was tested under different pressure temperature and pH conditions of leaching solution (pH=9.8) in order to optimize time and efficiency of each individual process. Four different unitary alcaline leaching processes were studied: MECHANICAL STIRRING, PNEUMATIC STIRRING, LEACHING IN AUTOCLAVE AND LEACHING IN COLUMNS. For these four processes were obtained recovery rates (in percentage) of 18.63 and 87.82; 17.03 and 82.57; 60.42 and 99.55; 2.5 and 30.10; respectively from raw and pre-toasted ore. After filtration, vanadium was extracted from enriched solutions by using liquid resin ALAMINE 336, selective for vanadium at pH=2.8. Vanadium was later discharged with a Sodium Carbonate solution (10 per cent) and finally precipitated as the commercial compound Ammonium Vanadate, NH4VO3. Nuclear techniques as X-ray fluorescence and Atomic Absorption spectroscopy were used for analysis all over the investigation

Bronsted acid site number evaluation using isopropylamine decomposition on Y-zeolite contaminated with vanadium in a simultaneous DSC-TGA analyzer

International Nuclear Information System (INIS)

Osorio Perez, Yonnathan; Forero, Liliam Alexandra Palomeque; Torres, Diana Vanessa Cristiano; Trujillo, Carlos Alexander

2008-01-01

Acid-site catalyzed decomposition of isopropylamine was followed in a simultaneous DSC-TGA analyzer. USY zeolite samples with and without vanadium were studied. Results show that acid sites number decreases linearly with vanadium concentration in zeolite indicating that vanadium neutralizes acid sites on catalyst and the metal is able to move on the surface of the solid. The neutralizing species probably contain only one vanadium atom. The reaction enthalpy plus desorption heat of the products show that vanadium preferentially neutralizes the strongest acid sites on the zeolite. The application of the simultaneous DSC-TGA technique to quantify Bronsted acid sites on solids by this reaction is novel

Examination of Amine-Functionalised Anion-Exchange Membranes for Possible Use in the All-Vanadium Redox Flow Battery

International Nuclear Information System (INIS)

Mallinson, Sarah L.; Varcoe, John R.; Slade, Robert C.T.

2014-01-01

The applicability of amine-functionalised anion-exchange membranes (AEMs) for use in the all-vanadium redox flow battery has been studied. A selection of radiation-grafted aminated membranes functionalised with dimethylamine, trimethylamine or diazabicyclo(2,2,2)octane were extensively tested. The success of each grafting process was confirmed by Raman and infrared spectroscopies, titrimetry and ionic conductivity measurements. The amine-functionalised membranes were found to have poor thermo-oxidative stability and high vanadium cation permeabilities. The results highlight the importance of balancing ionic conductivity with vanadium cation permeability and indicate that amine-based functional groups may not be suitably stable for the membranes to remain true AEMs when in use in the all-vanadium redox flow battery

Modulatory role of vanadium on trace element profile in diethylnitrosamine-induced rat hepatocarcinogenesis

Science.gov (United States)

Chakraborty, A.; Selvaraj, S.; Sudarshan, M.; Dutta, R. K.; Ghugre, S. S.; Chintalapudi, S. N.

2000-09-01

Particle-induced X-ray emission (PIXE) analysis was employed in the present study to investigate the chemopreventive potential of vanadium in influencing trace elemental profile and antioxidant status in chemical carcinogenesis. The elements with Z=15-40 were studied. Data reveal remarkable alterations in elemental composition in the hepatic tissue of diethylnitrosamine (DENA)-induced Sprague-Dawley male rats (intraperitoneal (ip) dose: 200 mg/kg body weight) after four weeks of induction. Several elements like Mn, Cu, Zn, Rb showed large depletion while other elements like Fe, Ca, K, Br showed large enhancement in comparison to that of the normal control animals. These elements compete for binding sites in the cell, change its enzymatic activity and exert direct or indirect action on the carcinogenic process. Supplementary vanadium (0.5 ppm ad libitum in drinking water) has shown effective modulation by alteration in the concentration of trace elements in the tumorigenic tissue ( Pcomposition, antioxidant status in the initiation phase of carcinogenesis and the period of exposure to vanadium. The possibility of selecting vanadium as a therapeutic agent for chemoprevention is discussed in the light of its influence in maintaining trace elemental homeostasis, a parameter of importance in cancer prevention research.

Ethylenediamine-functionalized graphene oxide incorporated acid-base ion exchange membranes for vanadium redox flow battery

International Nuclear Information System (INIS)

Liu, Shuai; Li, Dan; Wang, Lihua; Yang, Haijun; Han, Xutong; Liu, Biqian

2017-01-01

Highlights: • Ethylenediamine functionalized graphene oxide. • Layered structure of functionalized graphene oxide block vanadium ions crossover. • Protonated N-containing groups suppress vanadium ions permeation. • Ion transport channels are narrowed by electrostatic interactions. • Vanadium crossover decreased due to enhanced Donnan effect and special structure. - Abstract: As a promising large-scale energy storage battery, vanadium redox flow battery (VRFB) is urgently needed to develop cost-effective membranes with excellent performance. Novel acid-base ion exchange membranes (IEMs) are fabricated based on sulfonated poly(ether ether ketone) (SPEEK) matrix and modified graphene oxide (GO) by solution blending. N-based functionalized graphene oxide (GO-NH 2 ) is fabricated by grafting ethylenediamine onto the edge of GO via a facile method. On one hand, the impermeable layered structures effectively block ion transport pathway to restrain vanadium ions crossover. On the other hand, acid-base pairs form between −SO 3 − groups and N-based groups on the edge of GO nanosheets, which not only suppress vanadium ions contamination but also provide a narrow pathway for proton migration. The structure is beneficial for achieving an intrinsic balance between conductivity and permeability. By altering amounts of GO-NH 2 , a sequence of acid-base IEMs are characterized in detail. The single cells assembled with acid-base IEMs show self-discharge time for 160 h, capacity retention 92% after 100 cycle, coulombic efficiency 97.2% and energy efficiency 89.5%. All data indicate that acid-base IEMs have promising prospects for VRFB applications.

Study using macroscopic autoradiography of the distribution of vanadium 48 in the rat and mouse

International Nuclear Information System (INIS)

Serhrouchni, M.

1982-07-01

Study of vanadium 48 distribution in the laboratory animal by macroscopic autoradiography. Vanadium 48 bioavailability is zero after oral administration and good after pulmonary administration. It is distributed throughout the body with a particular affinity for bone and teeth. Study of perinatal metabolism [fr

Electrochemistry of vanadium(II and the electrodeposition of aluminum-vanadium alloys in the aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt

Directory of Open Access Journals (Sweden)

Tsuda T.

2003-01-01

Full Text Available The electrochemical behavior of vanadium(II was examined in the 66.7-33.3 mole percent aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt containing dissolved VCl2 at 353 K. Voltammetry experiments revealed that V(II could be electrochemically oxidized to V(III and V(IV. However at slow scan rates the V(II/V(III electrode reaction is complicated by the rapid precipitation of V(III as VCl3. The reduction of V(II occurs at potentials considerably negative of the Al(III/Al electrode reaction, and Al-V alloys cannot be electrodeposited from this melt. However electrodeposition experiments conducted in VCl2-saturated melt containing the additive, 1-ethyl-3-methylimidazolium tetrafluoroborate, resulted in Al-V alloys. The vanadium content of these alloys increased with increasing cathodic current density or more negative applied potentials. X-ray analysis of Al-V alloys that were electrodeposited on a rotating copper wire substrate indicated that these alloys did not form or contain an intermetallic compound, but were non-equilibrium or metastable solid solutions. The chloride-pitting corrosion properties of these alloys were examined in aqueous NaCl by using potentiodynamic polarization techniques. Alloys containing ~10 a/o vanadium exhibited a pitting potential that was 0.3 V positive of that for pure aluminum.

Low Permeable Hydrocarbon Polymer Electrolyte Membrane for Vanadium Redox Flow Battery.

Science.gov (United States)

Jung, Ho-Young; Moon, Geon-O; Jung, Seunghun; Kim, Hee Tak; Kim, Sang-Chai; Roh, Sung-Hee

2017-04-01

Polymer electrolyte membrane (PEM) confirms the life span of vanadium redox flow battery (VRFB). Products from Dupont, Nafion membrane, is mainly used for PEM in VRFB. However, permeation of vanadium ion occurs because of Nafion’s high permeability. Therefore, the efficiency of VRFB decreases and the prices becomes higher, which hinders VRFB’s commercialization. In order to solve this problem, poly(phenylene oxide) (PPO) is sulfonated for the preparation of low-priced hydrocarbon polymer electrolyte membrane. sPPO membrane is characterized by fundamental properties and VRFB cell test.

One-step preparation and photocatalytic performance of vanadium doped TiO2 coatings

International Nuclear Information System (INIS)

Vasilić, R.; Stojadinović, S.; Radić, N.; Stefanov, P.; Dohčević-Mitrović, Z.; Grbić, B.

2015-01-01

In this paper, we have investigated one-step preparation of vanadium doped TiO 2 coatings formed by plasma electrolytic oxidation (PEO) of titanium in electrolyte containing 10 g/L Na 3 PO 4 ·12H 2 O + 0.5 g/L NH 4 VO 3 . The morphology, phase structure, and elemental composition of the formed coatings were characterized by atomic force microscopy (AFM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) techniques. Ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS) was employed to evaluate the band gap energy of obtained coatings. Vanadium doped TiO 2 coatings are partly crystallized and mainly composed of anatase phase TiO 2 , with up to about 2 wt% of vanadium present in the surface layer of the oxide. The valence band photoelectron spectra and UV–Vis DRS showed that vanadium doped TiO 2 coatings exhibit notable red shift with respect to the pure TiO 2 coatings. The photocatalytic activity was evaluated by monitoring the degradation of methyl orange under simulated sunlight conditions. Photocatalytic activity of vanadium doped TiO 2 coatings increases with PEO time. Prolonged PEO times result in higher roughness of obtained coatings, thus increasing surface area available for methyl orange degradation. Vanadium doped TiO 2 coatings obtained after 180 s of PEO time exhibit the best photocatalytic activity and about 67% of methyl orange is degraded after 12 h of irradiation under simulated sunlight. - Highlights: • One-step preparation of V-doped TiO 2 coatings in 10 g/L Na 3 PO 4 ·12H 2 O + 0.5 g/L NH 4 VO 3 . • Properties of obtained coatings strongly depend on microdischarge characteristics. • Band gap of V-doped TiO 2 coatings is shifted towards red side of the spectrum. • V-doped TiO 2 coatings have better photocatalytic activity than pure TiO 2 . • After 12 h of simulated sunlight irradiation, 67% of methyl orange was decomposed

Multi-physics Model for the Aging Prediction of a Vanadium Redox Flow Battery System

International Nuclear Information System (INIS)

Merei, Ghada; Adler, Sophie; Magnor, Dirk; Sauer, Dirk Uwe

2015-01-01

Highlights: • Present a multi-physics model of vanadium redox-flow battery. • This model is essential for aging prediction. • It is applicable for VRB system of different power and capacity ratings. • Good results comparing with current research in this field. - Abstract: The all-vanadium redox-flow battery is an attractive candidate to compensate the fluctuations of non-dispatchable renewable energy generation. While several models for vanadium redox batteries have been described yet, no model has been published, which is adequate for the aging prediction. Therefore, the present paper presents a multi-physics model which determines all parameters that are essential for an aging prediction. In a following paper, the corresponding aging model of vanadium redox flow battery (VRB) is described. The model combines existing models for the mechanical losses and temperature development with new approaches for the batteries side reactions. The model was implemented in Matlab/Simulink. The modeling results presented in the paper prove to be consistent with the experimental results of other research groups

Investigation into cobalt, copper and vanadium complexes with phenylbenzimidazolylazoketoxime and o-phenanthroline

Energy Technology Data Exchange (ETDEWEB)

Dubinina, L F; Lipunova, G N; Medvedeva, L I; Mertsalov, S L [Ural' skij Politekhnicheskij Inst., Sverdlovsk (USSR)

1983-01-01

Complex formation of phenylbenzimidozolylazoketoxime (PhBAKO) with Co(2), Cu(2) and V(5) ions in aqueous-ethanol medium at different pH values, is investigated. In aqueous-ethanol medium PhBAKO forms coloured complexes. Reagent has a low selectivity under these conditions. It is found that the addition of phenanthroline not only increases the contrast of the reaction but considerably increases its selectivity. The optimum range of pH value of complex formation for vanadium is 6.0-8.2. A high selectivity of PhBAKO and the contrast nature of complex formation reaction of the reagent with cobalt copper and vanadium ions, different stability of complexes in the acidic medium have permitted to develop the photometric method of determination of these elements in natural waters in the case of their mutual presence. The limit of vanadium detection is 0.01 ..mu..g/ml.

Graphite furnace atomic absorption spectrometric determination of vanadium after cloud point extraction in the presence of graphene oxide

Science.gov (United States)

López-García, Ignacio; Marín-Hernández, Juan José; Hernández-Córdoba, Manuel

2018-05-01

Vanadium (V) and vanadium (IV) in the presence of a small concentration of graphene oxide (0.05 mg mL-1) are quantitatively transferred to the coacervate obtained with Triton X-114 in a cloud point microextraction process. The surfactant-rich phase is directly injected into the graphite atomizer of an atomic absorption spectrometer. Using a 10-mL aliquot sample and 150 μL of a 15% Triton X-114 solution, the enrichment factor for the analyte is 103, which results in a detection limit of 0.02 μg L-1 vanadium. The separation of V(V) and V(IV) using an ion-exchanger allows speciation of the element at low concentrations. Data for seven reference water samples with certified vanadium contents confirm the reliability of the procedure. Several beer samples are also analyzed, those supplied as canned drinks showing low levels of tetravalent vanadium.

In-Plane Impedance Spectroscopy measurements in Vanadium Dioxide thin films

Science.gov (United States)

Ramirez, Juan; Patino, Edgar; Schmidt, Rainer; Sharoni, Amos; Gomez, Maria; Schuller, Ivan

2012-02-01

In plane Impedance Spectroscopy measurements have been done in Vanadium Dioxide thin films in the range of 100 Hz to 1 MHz. Our measurements allows distinguishing between the resistive and capacitive response of the Vanadium Dioxide films across the metal-insulator transition. A non ideal RC behavior was found in our thin films from room temperature up to 334 K. Around the MIT, an increase of the total capacitance is observed. A capacitor-network model is able to reproduce the capacitance changes across the MIT. Above the MIT, the system behaves like a metal as expected, and a modified equivalent circuit is necessary to describe the impedance data adequately.

Spectrophotometric determination of catecholamine using vanadium and eriochrome cyanine r

International Nuclear Information System (INIS)

Nagaraja, Padmarajaiah; Shrestha, Ashwinee Kumar; Shivakumar, Anantharaman; Al-Tayar, Naef Ghallab Saeed; Gowda, Avinask K.

2011-01-01

highly sensitive spectrophotometric method for the analysis of catecholamine drugs; L-dopa and methyldopa, is described. The analysis is based on the reaction of drug molecules with vanadium (V) which is reduced to vanadium (IV) and form complex with eriochrome cyanine R to give products having maximum absorbance (λ max ) at 565 nm. Beer's law is obeyed in the range 0.028-0.84 and 0.099-0.996 μg mL -1 for L-dopa and methyldopa, respectively. The statistical analysis as well as comparison with reported methods demonstrated high precision and accuracy of the proposed method. The method was successfully applied in the analysis of pharmaceutical preparations. (author)

Critical safety features of the vanadium redox flow battery

Science.gov (United States)

Whitehead, A. H.; Rabbow, T. J.; Trampert, M.; Pokorny, P.

2017-05-01

In this work the behaviour of the vanadium redox flow battery is examined under a variety of short-circuit conditions (e.g. with and without the pumps stopping as a result of the short). In contrast to other battery types, only a small proportion of the electroactive material, in a flow battery, is held between the electrodes at any given time. Therefore, together with the relatively low energy density of the vanadium electrolyte, the immediate release of energy, which occurs as a result of electrical shorting, is somewhat limited. The high heat capacity of the aqueous electrolyte is also beneficial in limiting the temperature rise. It will be seen that the flow battery is therefore considerably safer than other battery types, in this respect.

Determination of hafnium, molybdenum, and vanadium in niobium and niobium-based alloys by atomic absorption spectrometry

International Nuclear Information System (INIS)

Ide, Kunikazu; Kobayashi, Takeshi; Sudo, Emiko.

1985-01-01

The analytical procedure is as follows: Weigh 1 g of a sample and put it into a 100 cm 3 PTFE beaker. Add 5 ml of distilled water and 5 ml of hydrofluoric acid, and then heat the solution on a hot plate, adding 3 ml of nitric acid dropwise. Dilute the solution to 100 cm 3 with distilled water. When hafnium is determined, add 2 g of diammonium titanium hexafluoride ((NH 4 ) 2 TiF 6 )) before dilution. Working standard solutions are prepared by adding the stock standard solutions of hafnium, molybdenum, and vanadium into niobium solutions. When hafnium is determined, add 2 g of (NH 4 ) 2 TiF 6 and the alloying elements in amounts corresponding to those in sample solutions into the working standard solutions. The tolerable amounts of hydrofluoric acid were 2.9 M, 2.1 M, and 3.1 M and those of nitric acid were 1.0 M, 1.6 M, and 1.6 M for hafnium, molybdenum, and vanadium, respectively. It was found that (NH 4 ) 2 TiF 6 greatly increased the sensitivity for hafnium determination. Niobium showed minus effect for hafnium and plus effect for molybdenum and vanadium. The atomic absorption of molybdenum and vanadium were not influenced by the presence of 20 % of each alloying element, while the atomic absorption of hafnium was given plus effect by 20 % of zirconium, iron, cobalt, nickel, manganese, chromium or vanadium and minus effect by 20 % tungsten. The analytical values of hafnium, molybdenum, and vanadium in niobium-based alloys by this method showed a good agreement with those by X-ray fluorescence analysis. The lower limits of determination (S/N=2) were 0.05, 0.001, and 0.002 % and the relative standard deviation were 3, 1, and 1.5 % for hafnium, molybdenum, and vanadium, respectively. (author)

A Contemporary Treatment Approach to Both Diabetes and Depression by Cordyceps sinensis, Rich in Vanadium

Directory of Open Access Journals (Sweden)

Jian-You Guo

2010-01-01

Full Text Available Diabetes mellitus is accompanied by hormonal and neurochemical changes that can be associated with anxiety and depression. Both diabetes and depression negatively interact, in that depression leads to poor metabolic control and hyperglycemia exacerbates depression. We hypothesize one novel vanadium complex of vanadium-enriched Cordyceps sinensis (VECS, which is beneficial in preventing depression in diabetes, and influences the long-term course of glycemic control. Vanadium compounds have the ability to imitate the action of insulin, and this mimicry may have further favorable effects on the level of treatment satisfaction and mood. C. sinensis has an antidepressant-like activity, and attenuates the diabetes-induced increase in blood glucose concentrations. We suggest that the VECS may be a potential strategy for contemporary treatment of depression and diabetes through the co-effect of C. sinensis and vanadium. The validity of the hypothesis can most simply be tested by examining blood glucose levels, and swimming and climbing behavior in streptozotocin-induced hyperglycemic rats.

Balancing Osmotic Pressure of Electrolytes for Nanoporous Membrane Vanadium Redox Flow Battery with a Draw Solute.

Science.gov (United States)

Yan, Ligen; Li, Dan; Li, Shuaiqiang; Xu, Zhi; Dong, Junhang; Jing, Wenheng; Xing, Weihong

2016-12-28

Vanadium redox flow batteries with nanoporous membranes (VRFBNM) have been demonstrated to be good energy storage devices. Yet the capacity decay due to permeation of vanadium and water makes their commercialization very difficult. Inspired by the forward osmosis (FO) mechanism, the VRFBNM battery capacity decrease was alleviated by adding a soluble draw solute (e.g., 2-methylimidazole) into the catholyte, which can counterbalance the osmotic pressure between the positive and negative half-cell. No change of the electrolyte volume has been observed after VRFBNM being operated for 55 h, revealing that the permeation of water and vanadium ions was effectively limited. Consequently, the Coulombic efficiency (CE) of nanoporous TiO 2 vanadium redox flow battery (VRFB) was enhanced from 93.5% to 95.3%, meanwhile, its capacity decay was significantly suppressed from 60.7% to 27.5% upon the addition of soluble draw solute. Moreover, the energy capacity of the VRFBNM was noticeably improved from 297.0 to 406.4 mAh remarkably. These results indicate balancing the osmotic pressure via the addition of draw solute can restrict pressure-dependent vanadium permeation and it can be established as a promising method for up-scaling VRFBNM application.

Nickel and vanadium in air particulates at Dhahran (Saudi Arabia) during and after the Kuwait oil fires

Science.gov (United States)

Sadiq, M.; Mian, A. A.

Air particulates, both the total suspended (TSP) and inhalable (PM 10, smaller than 10 microns in size), were collected during and after the Kuwait oil fires (from March 1991 to July 1992) using Hi-Vol samplers. These samples were wet-digested at 120°C in an aqua regia and perchloric acids mixture for 3 h. Air particulate samples collected in 1982 at the same location were prepared similarly. Concentrations of nickel and vanadium were determined in the aliquot samples using an inductively coupled argon plasma analyser (ICAP). The monthly mean concentrations of nickel and vanadium, on volume basis, increased rapidly from March to June and decreased sharply during July-August in 1991. The minimum mean concentrations of these elements were found in the particulate samples collected in December 1991 which gradually increased through May 1992. Like 1991, nickel and vanadium concentrations in the air particulates spiked in June and decreased again in July 1992. This distribution pattern of nickel and vanadium concentrations was similar to that of the predominant wind from the north (Kuwait). In general, concentrations of these elements were higher in the air particulates collected during April-July 1991 as compared with those collected in 1992 during the same period. The TSPs contained higher concentrations of nickel and vanadium than those found in the PM 10 samples. However, this trend was reversed when concentrations of nickel and vanadium, on were expressed on particulate weight basis. The monthly mean concentrations of nickel and vanadium, on weight basis, decreased gradually through 1991 and increased slightly from March to July 1992. Concentrations of these elements were significantly higher in the air particulate samples collected in 1991 than those samples collected during 1982 at the same location. The data of this study suggest a contribution of the Kuwait oil fires in elevating nickel and vanadium concentrations in the air particulates at Dhahran during

Singlet oxygenation in microemulsion catalysed by vanadium chloroperoxidase

NARCIS (Netherlands)

Renirie, R.; Pierlot, C.; Wever, R.; Aubry, J.-M.

2009-01-01

Non-ionic microemulsions compatible with the enzyme vanadium chloroperoxidase were designed to perform singlet oxygenation of apolar substrates. The media were based on mono- and polydisperse ethoxylated fatty alcohols (CiEj). octane and aqueous buffer. "Fish" diagrams were determined to identify

Sulfonated Poly(Ether Ether Ketone)/Functionalized Carbon Nanotube Composite Membrane for Vanadium Redox Flow Battery Applications

International Nuclear Information System (INIS)

Jia, Chuankun; Cheng, Yuanhang; Ling, Xiao; Wei, Guanjie; Liu, Jianguo; Yan, Chuanwei

2015-01-01

A novel sulfonated poly(ether ether ketone) (SPEEK) membrane embedded with the short-carboxylic multi-walled carbon nanotube (we name it as SPEEK/SCCT membrane) for vanadium redox flow battery (VRB) has been prepared with low capacity loss, low cost and high energy efficiency. The mechanical strength, vanadium ions permeability and performance of the membrane in the VRB single cell were characterized. Results showed that the SPEEK/SCCT membrane possessed low permeability of vanadium ions, accompanied by higher mechanical strength than the Nafion 212 membrane. The VRB single cell with SPEEK/SCCT membrane showed 7% higher coulombic efficiency (CE), 6% higher energy efficiency (EE) but lower capacity loss in comparison with the one with Nafion 212. The good cell performance, low capacity loss and high vanadium ions barrier properties of the blend membrane is of significant interest for VRB applications

77 FR 54897 - Ferrovanadium and Nitrided Vanadium from the Russian Federation: Revocation of Antidumping Duty...

Science.gov (United States)

2012-09-06

... foreseeable time.\\5\\ \\5\\ See ITC Final and Ferrovanadium and Nitrided Vanadium From Russia: Investigation No... nitrided vanadium from the Russian Federation (Russia) would not be likely to lead to continuation or... foreseeable time,\\1\\ the Department of Commerce (the Department) is publishing this notice of revocation of...

Hydrogen adsorption on activated carbon nanotubes with an atomic-sized vanadium catalyst investigated by electrical resistance measurements

International Nuclear Information System (INIS)

Im, Ji Sun; Yun, Jumi; Kang, Seok Chang; Lee, Sung Kyu; Lee, Young-Seak

2012-01-01

Activated multi-walled carbon nanotubes were prepared with appended vanadium as a hydrogen storage medium. The pore structure was significantly improved by an activation process that was studied using Raman spectroscopy, field emission transmission electron microscopy and pore analysis techniques. X-ray photoelectron spectroscopy and X-ray diffraction results reveal that the vanadium catalyst was introduced into the carbon nanotubes in controlled proportions, forming V 8 C 7 . The improved pore structure functioned as a path through the carbon nanotubes that encouraged hydrogen molecule adsorption, and the introduced vanadium catalyst led to high levels of hydrogen storage through the dissociation of hydrogen molecules via the spill-over phenomenon. The hydrogen storage behavior was investigated by electrical resistance measurements for the hydrogen adsorbed on a prepared sample. The proposed mechanism of hydrogen storage suggests that the vanadium catalyst increases not only the amount of hydrogen that is stored but also the speed at which it is stored. A hydrogen storage capacity of 2.26 wt.% was achieved with the activation effects and the vanadium catalyst at 30 °C and 10 MPa.

Oxidation phase growth diagram of vanadium oxides film fabricated by rapid thermal annealing

Institute of Scientific and Technical Information of China (English)

Tamura KOZO; Zheng-cao LI; Yu-quan WANG; Jie NI; Yin HU; Zheng-jun ZHANG

2009-01-01

Thermal evaporation deposited vanadium oxide films were annealed in air by rapid thermal annealing (RTP). By adjusting the annealing temperature and time, a series of vanadium oxide films with various oxidation phases and surface morphologies were fabricated, and an oxidation phase growth diagram was established. It was observed that different oxidation phases appear at a limited and continuous annealing condition range, and the morphologic changes are related to the oxidation process.

Benchmark experiment on vanadium assembly with D-T neutrons. Leakage neutron spectrum measurement

Energy Technology Data Exchange (ETDEWEB)

Kokooo; Murata, I.; Nakano, D.; Takahashi, A. [Osaka Univ., Suita (Japan); Maekawa, F.; Ikeda, Y.

1998-03-01

The fusion neutronics benchmark experiments have been done for vanadium and vanadium alloy by using the slab assembly and time-of-flight (TOF) method. The leakage neutron spectra were measured from 50 keV to 15 MeV and comparison were done with MCNP-4A calculations which was made by using evaluated nuclear data of JENDL-3.2, JENDL-Fusion File and FENDL/E-1.0. (author)

Determination of total vanadium and vanadium(V) in groundwater from Mt. Etna and estimate of daily intake of vanadium(V) through drinking water.

Science.gov (United States)

Arena, Giovanni; Copat, Chiara; Dimartino, Angela; Grasso, Alfina; Fallico, Roberto; Sciacca, Salvatore; Fiore, Maria; Ferrante, Margherita

2015-06-01

Vanadium(V) can be found in natural waters in the form of V(IV) and V(V) species, which have different biological properties and toxicity. The purpose of this study was to determine the concentrations of total V and V(V) in groundwater from the area of Mt. Etna and to assess the estimated daily intake (EDI) of V(V) of adults and children through drinking water. Water was sampled monthly at 21 sites in 2011. Total vanadium was determined by inductively coupled plasma-mass spectrometry (ICP-MS) and speciation by ion chromatography-ICP-MS (IC-ICP-MS). The concentration of V(V) species ranged from 62.8 to 98.9% of total V, with significantly higher concentrations in samples from the S/SW slope of Mt. Etna. The annual mean concentrations of total V exceeded the Italian legal limit of 140 μg/L at four sites on the S/SW slope. In the absence of thresholds for V(V) intake, only the Environmental Protection Agency (EPA) has calculated a reference dose. Children's EDI of V(V) at the sites with the higher V concentrations exceeded EPA thresholds (9 μg/kg/day). In particular, we found in Camporotondo, Mascalucia, Ragalna and San Pietro Clarenza sites children's EDIs of 11, 9.3, 11 and 9.9, respectively. The EDI of V(V) was significantly higher than the literature range (0.09-0.34 μg/kg/day).

Lithium insertion in sputtered vanadium oxide film

DEFF Research Database (Denmark)

West, K.; Zachau-Christiansen, B.; Skaarup, S.V.

1992-01-01

were oxygen deficient compared to V2O5. Films prepared in pure argon were reduced to V(4) or lower. The vanadium oxide films were tested in solid-state lithium cells. Films sputtered in oxygen showed electrochemical properties similar to crystalline V2O5. The main differences are a decreased capacity...

Vanadium induces dopaminergic neurotoxicity via protein kinase Cdelta dependent oxidative signaling mechanisms: Relevance to etiopathogenesis of Parkinson's disease

International Nuclear Information System (INIS)

Afeseh Ngwa, Hilary; Kanthasamy, Arthi; Anantharam, Vellareddy; Song, Chunjuan; Witte, Travis; Houk, Robert; Kanthasamy, Anumantha G.

2009-01-01

Environmental exposure to neurotoxic metals through various sources including exposure to welding fumes has been linked to an increased incidence of Parkinson's disease (PD). Welding fumes contain many different metals including vanadium typically present as particulates containing vanadium pentoxide (V 2 O 5 ). However, possible neurotoxic effects of this metal oxide on dopaminergic neuronal cells are not well studied. In the present study, we characterized vanadium-induced oxidative stress-dependent cellular events in cell culture models of PD. V 2 O 5 was neurotoxic to dopaminergic neuronal cells including primary nigral dopaminergic neurons and the EC 50 was determined to be 37 μM in N27 dopaminergic neuronal cell model. The neurotoxic effect was accompanied by a time-dependent uptake of vanadium and upregulation of metal transporter proteins Tf and DMT1 in N27 cells. Additionally, vanadium resulted in a threefold increase in reactive oxygen species generation, followed by release of mitochondrial cytochrome c into cytoplasm and subsequent activation of caspase-9 (> fourfold) and caspase-3 (> ninefold). Interestingly, vanadium exposure induced proteolytic cleavage of native protein kinase Cdelta (PKCδ, 72-74 kDa) to yield a 41 kDa catalytically active fragment resulting in a persistent increase in PKCδ kinase activity. Co-treatment with pan-caspase inhibitor Z-VAD-FMK significantly blocked vanadium-induced PKCδ proteolytic activation, indicating that caspases mediate PKCδ cleavage. Also, co-treatment with Z-VAD-FMK almost completely inhibited V 2 O 5 -induced DNA fragmentation. Furthermore, PKCδ knockdown using siRNA protected N27 cells from V 2 O 5 -induced apoptotic cell death. Collectively, these results demonstrate that vanadium can exert neurotoxic effects in dopaminergic neuronal cells via caspase-3-dependent PKCδ cleavage, suggesting that metal exposure may promote nigral dopaminergic degeneration.

Rutile vanadium antimonates. A new class of catalysts for selective reduction of NO with ammonia

Energy Technology Data Exchange (ETDEWEB)

Brazdil, James F.; Ebner, Ann M.; Cavalcanti, Fernando A.P. [BP Chemicals Inc., Cleveland, OH (United States)

1997-12-31

This paper describes a new class of vanadium containing oxide catalysts that are active and selective for the selective catalytic reduction of NO with ammonia. Vanadium antimony oxide based catalysts were found to be effective in the conversion of NO with little or no ammonia slippage when tested using gas mixtures containing between 300 and 700ppm NO. X-ray diffraction analyses of the catalysts show that the dominant phase present in the catalyst is vanadium antimonate having a defect rutile crystal structure. The catalysts are active and selective in the ranges of 400-460C and gas hourly space velocities of 3000-8000h{sup -1}

Gas-phase complexes formed between amidoxime ligands and vanadium or iron investigated using electrospray ionization mass spectrometry.

Science.gov (United States)

Mustapha, Adetayo M; Pasilis, Sofie P

2016-08-15

Amidoxime-functionalized sorbents can be used to extract uranium from seawater. Iron(III) and vanadium(V) may compete with uranium for adsorption sites. We use 2,6-dihydroxyiminopiperidine (DHIP) and N(1) ,N(5) -dihydroxypentanediimidamide (DHPD) to model amidoxime functional groups and characterize the vanadium(V) and iron(III) complexes with these ligands. We also examine the effect of iron(III) and vanadium(V) on uranyl(VI) complexation by DHIP and DHPD. The experiments were carried out in positive ion mode using a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. The effect on the mass spectra of changes in ligand, metal:ligand mole ratio, and pH was examined. Iron(III) formed a 1:2 metal:ligand complex with DHIP at all metal:ligand mole ratios and pH values investigated; it formed both 1:2 and 1:3 metal:ligand complexes with DHPD. Vanadium(V) formed 1:1 and 1:2 metal:ligand complexes with DHIP. A 1:2 metal:ligand complex was formed with DHPD at all vanadium(V):DHPD mole ratios investigated. Changes in solution pH did not affect the ions observed. The relative binding affinities of the metal ions towards DHIP followed the order iron(III) > vanadium(V) > uranyl(VI). This study presents a first look at the gas-phase vanadium(V)- and iron(III)-DHIP and -DHPD complexes using electrospray ionization mass spectrometry. These metals form stronger complexes with amidoxime ligands than uranyl(VI), and will affect uranyl(VI) adsorption to amidoxime-based sorbents. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Inverted organic solar cells with solvothermal synthesized vanadium-doped TiO2 thin films as efficient electron transport layer

Institute of Scientific and Technical Information of China (English)

Mehdi Ahmadi; Sajjad Rashidi Dafeh; Samaneh Ghazanfarpour; Mohammad Khanzadeh

2017-01-01

We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly (3-hexylthiophene) P3HT:[6-6] phenyl-(6) butyric acid methyl ester (PCBM).1％ vanadium-doped TiO2 nanoparticles were synthesized via the solvothermal method.Crystalline structure,morphology,and optical properties of pure and vanadium-doped TiO2 thin films were studied by different techniques such as x-ray diffraction,scanning electron microscopy,transmittance electron microscopy,and UV-visible transmission spectrum.The doctor blade method which is compatible with roll-2-roll printing was used for deposition of pure and vanadium-doped TiO2 thin films with thicknesses of 30 nm and 60 nm.The final results revealed that the best thickness of TiO2 thin films for our fabricated cells was 30 nm.The cell with vanadium-doped TiO2 thin film showed slightly higher power conversion efficiency and great Jsc of 10.7 mA/cm2 compared with its pure counterpart.In the cells using 60 nm pure and vanadium-doped TiO2 layers,the cell using the doped layer showed much higher efficiency.It is remarkable that the extemal quantum efficiency of vanadium-doped TiO2 thin film was better in all wavelengths.

Efficient Solar Energy Storage Using A TiO2/WO3 Tandem Photoelectrode in An All-vanadium Photoelectrochemical Cell

International Nuclear Information System (INIS)

Liu, Dong; Wei, Zi; Hsu, Chia-jen; Shen, Yi; Liu, Fuqiang

2014-01-01

Using a photoelectrochemical (PEC) cell to convert solar energy to either electricity or chemical fuels has attracted much attention in the last four decades. However, two major obstacles that hinder wide-spread application of this approach lie in the relatively wide bandgap of chemically stable semiconducotrs, e.g., TiO 2 , and the rapid recombination of photogenerated charge carriers once they are generated within the semiconductors. We reported herein a method that utilized vanadium redox pairs, which are commonly used in vanadium redox-flow batteries (VRB), to mitigate charge carrier recombination and thus to improve photoresponse in regenerative solar energy storage for the first time. The results showed significant improvement in photocurrent during photo-charging of the all-vanadium PEC storage cell with the addition of a very low morlarity of vanadium redox species (0.01 M) to the acid electrolytes. Additonally, the photocurrent was almost doubled even with a TiO 2 electrode when two vanadium redox species were used in a full-cell configuration instead of a half-cell setup. To further enhance the light absorption, a TiO 2 /WO 3 tandem electrode was studied and compared to the TiO 2 electrode in various vanadium redox electrolytes. The tandem electrode showed higher photoresponse in all electrolytes investigated. Furthermore, the important role of vanadium redox species and WO 3 have been discussed

Modulatory role of vanadium on trace element profile in diethylnitrosamine-induced rat hepatocarcinogenesis

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, A.; Selvaraj, S.; Sudarshan, M.; Dutta, R.K.; Ghugre, S.S.; Chintalapudi, S.N. E-mail: snc@iuccal.ernet.insnc@gamma.iuc.res.in

2000-09-01

Particle-induced X-ray emission (PIXE) analysis was employed in the present study to investigate the chemopreventive potential of vanadium in influencing trace elemental profile and antioxidant status in chemical carcinogenesis. The elements with Z=15-40 were studied. Data reveal remarkable alterations in elemental composition in the hepatic tissue of diethylnitrosamine (DENA)-induced Sprague-Dawley male rats (intraperitoneal (ip) dose: 200 mg/kg body weight) after four weeks of induction. Several elements like Mn, Cu, Zn, Rb showed large depletion while other elements like Fe, Ca, K, Br showed large enhancement in comparison to that of the normal control animals. These elements compete for binding sites in the cell, change its enzymatic activity and exert direct or indirect action on the carcinogenic process. Supplementary vanadium (0.5 ppm ad libitum in drinking water) has shown effective modulation by alteration in the concentration of trace elements in the tumorigenic tissue (P<0.001-0.005). Data reflect a definite correlation between elemental composition, antioxidant status in the initiation phase of carcinogenesis and the period of exposure to vanadium. The possibility of selecting vanadium as a therapeutic agent for chemoprevention is discussed in the light of its influence in maintaining trace elemental homeostasis, a parameter of importance in cancer prevention research.

Simultaneous determination of a binary mixture: kinetic method for determination of uranium and vanadium

International Nuclear Information System (INIS)

Jianhua, W.; Ronghuan, H.

1993-01-01

A kinetic method for simultaneous determination of a binary mixture is proposed, and a procedure for simultaneous determination of uranium (IV) and vanadium (IV) is established based on their inductive effect on chromium (VI)-iodide redox reaction in a weak acidic medium. The reaction was monitored by FIA-spectrophotometry using the I 3 - -starch complex as indicator. The calibration graphs are linear for uranium (IV) and vanadium (IV) within the range of 0 ∼ 3.6 μg/ml and 0 ∼ 2.5 μg/ml respectively. Most foreign ions, except for iron (II) and antimony (III), do not interfere with the determination. The uranium and vanadium content in different samples was determined, and the results were satisfactory. (author). 2 tabs., 2 figs., 9 refs

Vanadium Influence on Iron Based Intermetallic Phases in AlSi6Cu4 Alloy

Directory of Open Access Journals (Sweden)

Bolibruchová D.

2014-10-01

Full Text Available Negative effect of iron in Al-Si alloys mostly refers with iron based intermetallic phases, especially Al5FeSi phases. These phases are present in platelet-like forms, which sharp edges are considered as main cracks initiators and also as contributors of porosity formation. In recent times, addition of some elements, for example Mn, Co, Cr, Ni, V, is used to reduce influence of iron. Influence of vanadium in aluminium AlSi6Cu4 alloy with intentionally increased iron content is presented in this article. Vanadium amount has been graduated and chemical composition of alloy has been analysed by spectral analysis. Vanadium influence on microstructural changes was evaluated by microstructural analysis and some of intermetallic particles were reviewed by EDX analysis.

Atomic absorption determination of vanadium in products of metallurgical production and mineral feed stock

International Nuclear Information System (INIS)

Polikarpova, N.V.; Panteleeva, E.Yu.

1983-01-01

Rapid and selective method of atomic absorption determination of vanadium in metallurgical process products and numerical feed stock is suggested. Buffering mixture of aluminium and phosphoric acid is used to suppress the effect of sample composition on the value of vanadium atomic absorption. The concentration of buffer components can vary from 400 up to 2000 μg/ml Al and from 2 up to 5% vol. H 3 PO 4 . The suggested mixture completely eli-- minates the strong chromium effect. The developed method was used for analyzing steels, alloys based on Mo, Ni, Ti, Cr, as well as titanium magnetite ores and concentrates. The method enables to determine from 0.05 up to 10% vanadium with 0.05-0.01 relative standard deviation, respectively

Extraction and separation of molybdenum and vanadium from acidic and alkaline media using tertiary and quaternary amines

International Nuclear Information System (INIS)

Stas, J.; Dahdouh, A.; Rizkallah, I.

2010-01-01

The extraction of vanadium and molybdenum from alkaline leaching solutions coming from the leaching of fly ash of fired electrical power stations by tri-n dodecylamine (TDA) and metyl trioctyl ammonium chloride (QA) in the presence of octanol-2 as modifier in kerosene has been investigated. Some parameters influencing the extraction process have been studied (agitation time, octanol-2 percentage in the organic phase, pH of the aqueous phase, concentration of TDA and QA, concentration of vanadium in the aqueous phase and temperature). It has been shown that the extraction capacity of both V and Mo by TDA increases by decreasing the pH of the aqueous phase and reaches a maximum extraction at pH=2. The concentration of TDA plays an important role on the separation selectivity between these two elements, where the selectivity of Mo vs V (S M o, v=[Mo] o rg/[V] o rg) increases with the decrease of TDA concentration to reach a maximum selectivity value of S M o, v = 0.37 for [TDA]=1.5 M. It has been also shown that, whatever vanadium concentration in the aqueous phase, molybdenum will be first extracted, then the remaining free TDA will be occupied by vanadium. Concerning the quaternary amine QA, the pH value of the aqueous phase plays an important role in the separation process between vanadium and molybdenum, where the value of the selectivity of V vs Mo (S v , Mo=[V] o rg/[Mo] o rg) is maximal for pH>8 and the pH=8.5 is the best value which permit a good separation between these two elements at QA concentration equal to 6%, especially at high vanadium concentration. It is very important to note that for low vanadium concentration and at pH=1.5 the value of the selectivity of Mo vs V (S M o,v) increases with increasing Mo concentration in the aqueous phase which enable us the separation between these two elements under these experimental conditions, where Mo will be much more extracted than vanadium. The stripping of vanadium and molybdenum from the loaded organic

Solution XAS Analysis for Exploring the Active Species in Homogeneous Vanadium Complex Catalysis

Science.gov (United States)

Nomura, Kotohiro; Mitsudome, Takato; Tsutsumi, Ken; Yamazoe, Seiji

2018-06-01

Selected examples in V K-edge X-ray Absorption Near Edge Structure (XANES) analysis of a series of vanadium complexes containing imido ligands (possessing metal-nitrogen double bond) in toluene solution have been introduced, and their pre-edge and the edge were affected by their structures and nature of ligands. Selected results in exploring the oxidation states of the active species in ethylene dimerization/polymerization using homogeneous vanadium catalysts [consisting of (imido)vanadium(V) complexes and Al cocatalysts] by X-ray absorption spectroscopy (XAS) analyses have been introduced. It has been demonstrated that the method should provide more clear information concerning the active species in situ, especially by combination with the other methods (NMR and ESR spectra, X-ray crystallographic analysis, and reaction chemistry), and should be powerful tool for study of catalysis mechanism as well as for the structural analysis in solution.

The effect of transition metals additions on the temperature coefficient of linear expansion of titanium and vanadium

International Nuclear Information System (INIS)

Lesnaya, M.I.; Volokitin, G.G.; Kashchuk, V.A.

1976-01-01

Results are reported of an experimental research into the influence of small additions of α-transition metals on the temperature coefficient of linear expansion of titanium and vanadium. Using the configuration model of substance as the basis, expeained are the lowering of the critical liquefaction temperature or the melting point of vanadium and the raising of it, as caused by the addition of metals of the 6 group of the periodic chart and by the addition of metals of the 8 group, respectively, and also a shift in the temperature of the polymorphic α-β-transformation of titanium. Suggested as the best alloying metal for vanadium are tungsten and tantalum; for titaniums is vanadium whose admixtures lower the melting point and shift the polymorphic transformation temperature by as much as 100 to 120 degrees

Decomposition of hydrogen peroxide on nickel oxide - vanadium pentoxide catalysts and the effect of ionizing radiation on them

International Nuclear Information System (INIS)

Mucka, V.

1984-01-01

Some physico-chemical and catalytic properties of nickel oxide-vanadium pentoxide two-component catalysts were studied over the entire concentration range of the components, using the decomposition of hydrogen peroxide in an aqueous solution as the test reaction. The two oxides were found to affect each other; this was shown by the dependences of the specific surface area, the V 4+ ion concentration, and the catalyst activity on the system composition. At low vanadium pentoxide concentrations (up to 15 mol%) the reaction took place on nickel oxide modified with vanadium pentoxide, whereas in the region of higher vanadium pentoxide concentrations the decomposition of the peroxide was catalyzed primarily in the homogeneous phase by vanadium(V) peroxide ions; in a sample with 30 mol% V 2 O 5 , trivalent vanadium also played a part. With catalysts obtained by mere mechanical mixing of the two oxides, a modified activity was observed in the region of high excess of nickel oxide. The activity of catalyst, particularly pure nickel oxide, was increased by its partial reduction and decreased by its exposure to gamma radiation if the dose was higher than 10 5 Gy. The effects observed are interpreted in terms of the concept of bivalent catalytic centres. (author)

Effect of nitrogen concentration on temperature dependent mechanical properties of vanadium

International Nuclear Information System (INIS)

Carlson, O.N.; Rehbein, D.K.

1979-01-01

The critical resolved shear stress and strain rate sensitivity of vanadium were determined for vanadium-nitrogen alloys over the temperature range of 77K to 400K for concentrations of 1 to 500 wt ppm nitrogen. The concentration dependence of the hardening rate agrees quite well with either the Fleischer or Labusch strengthening model but the combined temperature and concentration dependence follows more closely the form predicted by Ono and Sommer. The strain rate sensitivity exhibits a peak at 140K which decreases with increasing nitrogen content but above 250K there is a reversal in this effect. (orig.) [de

Supervanadophile: Complexation, preconcentration and transport studies of vanadium by octa functionalized calix [4] resorcinarene - hydroxamic acid

International Nuclear Information System (INIS)

Jain, V. K.; Pillai, S. G.; Gupte, H. S.

2008-01-01

A new octa functionalized calix[4] resorcinarene bearing eight hydroxamic acid groups has been synthesized and its analytical properties have been investigated. To elucidate the structure of the compound, elemental analysis, fourier transform infrared and 1 H NMR spectral data have been used. The compound showed high affinity and selectivity for vanadium(V) in presence of large quantities of associated metal ions. The complexation of vanadium(V) with octa functionalized calix[4] resorcinarene bearing eight hydroxamic acid has a 4:1 metal: ligand stoichiometry as evaluated by Job's plot. A spectrophotometric method is proposed for the extractive determination of vanadium(V) in an acidic medium in the presence of diversified matrix, and verified by inductively coupled plasma-atomic emission spectrometry. Under the optimum condition of acidity, solvent, interfering ions and octa functionalized calix[4] resorcinarene bearing eight hydroxamic acid concentration, the molar absorptivity of the complex is 5630 1 mol -1 cm -1 at 495 nm. The system obeys Beer's law over the range 0.125-8.75 μg ml -1 of vanadium(V) with Sandell sensitivity 0.009 μg cm -2 . The preconcentration factor and overall stability constant evaluated at 25 d eg C were 142 and 14.18, respectively. The complexation is characterized by favorable enthalpy and entropy changes. Liquid membrane transport studies of vanadium(V) were carried out from source to the receiving phase under controlled conditions and a mechanism for transport is suggested. To check the validity of the proposed method, vanadium is determined in environmental, biological samples and some standard reference materials from NIST and BCS

Muon diffusion and trapping studies in high purity vanadium

International Nuclear Information System (INIS)

Heffner, R.H.; Brown, J.A.; Hutson, R.L.; Leon, M.; Parkin, D.M.; Schillaci, M.E.; Gauster, W.B.; Carlson, O.N.; Rehbein, D.K.; Fiory, A.T.

1979-01-01

The authors present the results of a study of the effects of varying impurity concentration on the temperature dependence of the depolarization rate of positive muons implanted into vanadium. Data are reported for the most highly purified polycrystalline sample yet measured, and the same sample subsequently doped with about 500 ppm oxygen by weight. The data for the pure sample shows a low depolarization rate ( -1 ) at all temperatures measured, showing a broad minimum centered at approximately 35 K, followed by a sharp peak near 90 K and a rapid drop to negligible values at 200 K. The data is contrasted with previously published data on less pure samples, and calls into question previous interpretations of the behavior of the μ + at low temperatures in impure vanadium as one-phonon-assisted tunneling. (Auth.)

Muon diffusion and trapping studies in high purity vanadium

International Nuclear Information System (INIS)

Heffner, R.H.; Brown, J.A.; Hutson, R.L.; Leon, M.; Gauster, W.B.; Carlson, O.N.; Rehbein, D.K.; Fiory, A.T.

1978-01-01

The first results of a study of the effects of varying impurity concentration on the temperature dependence of the depolarization rate of positive muons implanted into vanadium are presented. Data are reported for the most highly purified polycrystalline sample yet measured, and the same sample subsequently doped with about 500 ppM oxygen by weight. The data for the pure sample shows a low depolarization rate ( -1 ) at all temperatures measured, showing a broad minimum centered at approx. 35 K, followed by a sharp peak near 90 K and a rapid drop to negligible values at 200 K. The data are contrasted with previously published data on less pure samples, and call into question previous interpretations of the behavior of the μ + at low temperatures in impure vanadium as one-phonon-assisted tunneling. 6 references

Positron annihilation in sodium and copper β-vanadium oxide bronzes

International Nuclear Information System (INIS)

Dryzek, J.; Rogowska, E.

1990-01-01

Studies of copper and sodium β-vanadium oxide bronzes are performed using positron annihilation measured with a long slit angular correlation apparatus. The dependences of peak coincidence rate on temperature (40 to 310deg C) are obtained for different concentrations of donor atoms in the case of copper vanadium oxide bronzes. A three-states model corresponding to the annihilation of positrons in donor atom sublattice is applied for the description of the experimental data. The creation enthalpy of vacancies for that sublattice is equal to (0.60 ± 0.01) eV for Na 0.33 V 2 O 5 and equal to (0.64 ± 0.01) eV for Cu x V 2 O 5 . (author)

Crystallisation behavior and electronic conductivity of vanadium tellurite glass-ceramics

DEFF Research Database (Denmark)

Kjeldsen, Jonas; Yue, Yuanzheng; Rodrigues, A.C.M.

2012-01-01

is synthesized via the melt quenching technique, and crystalline 2TeO2-V2O5 is obtained by further heat-treatment of the quenched glass. Both states are confirmed by x-ray diffraction, scanning electron microscopy and differential scanning calorimetry. The redox state of vanadium is controlled via the melting...... and the ability to intercalate lithium-ions, it is a candidate for usage as cathode material. In the present work, we optimize the electronic conductivity of the congruent 2TeO2-V2O5 composition by tuning both the redox state of the vanadium and the overall degree of crystallinity. Amorphous 2TeO2-V2O5...

Speciation of Chromium and Vanadium in Medicinal Plants

African Journals Online (AJOL)

NICOLAAS

lamps of vanadium and chromium operating at 318.4 nm and. 357.9 nm have .... Table 1 Results for the determination of Cr and V in soil (n = 6). [Cr(VI)]. Total [Cr] .... hydrogen storage: Attributes for near-term, early market PEM fuel cells, Curr.

Molecular cloning, homology modeling and site-directed mutagenesis of vanadium-dependent bromoperoxidase (GcVBPO1) from Gracilaria changii (Rhodophyta).

Science.gov (United States)

Baharum, H; Chu, W-C; Teo, S-S; Ng, K-Y; Rahim, R Abdul; Ho, C-L

2013-08-01

Vanadium-dependent haloperoxidases belong to a class of vanadium enzymes that may have potential industrial and pharmaceutical applications due to their high stability. In this study, the 5'-flanking genomic sequence and complete reading frame encoding vanadium-dependent bromoperoxidase (GcVBPO1) was cloned from the red seaweed, Fracilaria changii, and the recombinant protein was biochemically characterized. The deduced amino acid sequence of GcVBPO1 is 1818 nucleotides in length, sharing 49% identity with the vanadium-dependent bromoperoxidases from Corralina officinalis and Cor. pilulifera, respectively. The amino acid residues associated with the binding site of vanadate cofactor were found to be conserved. The Km value of recombinant GcVBPO1 for Br(-) was 4.69 mM, while its Vmax was 10.61 μkat mg(-1) at pH 7. Substitution of Arg(379) with His(379) in the recombinant protein caused a lower affinity for Br(-), while substitution of Arg(379) with Phe(379) not only increased its affinity for Br(-) but also enabled the mutant enzyme to oxidize Cl(-). The mutant Arg(379)Phe was also found to have a lower affinity for I(-), as compared to the wild-type GcVBPO1 and mutant Arg(379)His. In addition, the Arg(379)Phe mutant has a slightly higher affinity for H2O2 compared to the wild-type GcVBPO1. Multiple cis-acting regulatory elements associated with light response, hormone signaling, and meristem expression were detected at the 5'-flanking genomic sequence of GcVBPO1. The transcript abundance of GcVBPO1 was relatively higher in seaweed samples treated with 50 parts per thousand (ppt) artificial seawater (ASW) compared to those treated in 10 and 30 ppt ASW, in support of its role in the abiotic stress response of seaweed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of iron supply on toxic effects of manganese, molybdenum and vanadium on soybean, peas, and flax

Energy Technology Data Exchange (ETDEWEB)

Warington, K

1954-01-01

The investigations were carried out in nutrient solution with iron as ferric citrate and nitrogen in the form of nitrate. The addition of 2.5 ppm vanadium to plants in which iron chlorosis was already established, either by a lack of iron or by excess manganese, failed to counteract the condition, and caused toxic symptoms. The reduction of the standard iron supply to 1/2 or 1/3 accentuated the toxicity of 2.5 or 5 ppm V to soybean and flax, but a similar reduction in phosphorus had no influence. The toxicity to peas, however, was increased when the phosphorus was reduced to 1/10, provided the iron level was high (20 ppm Fe). Raising the iron supply to 20 or 30 ppm counteracted the toxicity of manganese (10 ppm), molybdenum (40 ppm) and vanadium (2.5 ppm), but the result was less marked when these three elements were combined. Iron supplied in successive, small doses proved less efficient in overcoming molybdenum or vanadium, but not manganese excess, than the same amount of iron supplied in fewer and larger quantities. Varying the iron supply had little effect when the concentration of the three elements was low. When increased iron supply had reduced the chlorosis caused by high manganese or vanadium, it also reduced the manganese and vanadium contents of the shoot (ppm/dm), but the molybdenum content was only lowered by high iron when given in non-toxic concentrations (0.1 ppm Mo) combined with excess manganese. Yield data for soybean and flax indicated an interaction between manganese with both molybdenum and vanadium if the iron supply was low, but none between molybdenum and vanadium. The effect of all three metals was additive in respect to iron.

Recovery of vanadium (V) from spent catalysts used in sulfuric acid production units by acid or alkaline leaching

International Nuclear Information System (INIS)

Abdulbaki, M.; Stas, J.; Shino, O.; Asaad, K.; Al-Kassemi, H.; Al-Qabani, F.

2008-01-01

The present paper, studies the recovery of vanadium from the spent catalyst by using acidic or alkaline leaching technique. The optimal conditions of spent catalyst leaching have been studied. It has been shown that 20%(w/w) of sulfuric acid is the most suitable for leaching process at 70 Centigrade. The precipitation of vanadium using some alkaline media (Na 2 CO 3 , (NH 4 )CO 3 and NH 4 OH) has been also studied, it has been shown that ammonium hydroxide was the best at 60 degree, and iron was co-precipitated with vanadium which pollute the obtained red cake. So it is necessary to use liquid-liquid extraction technique for the separation between vanadium and iron and to have iron free red cake. (author)

Investigation of local environments in Nafion-SiO(2) composite membranes used in vanadium redox flow batteries.

Science.gov (United States)

Vijayakumar, M; Schwenzer, Birgit; Kim, Soowhan; Yang, Zhenguo; Thevuthasan, S; Liu, Jun; Graff, Gordon L; Hu, Jianzhi

2012-04-01

Proton conducting polymer composite membranes are of technological interest in many energy devices such as fuel cells and redox flow batteries. In particular, polymer composite membranes, such as SiO(2) incorporated Nafion membranes, are recently reported as highly promising for the use in redox flow batteries. However, there is conflicting reports regarding the performance of this type of Nafion-SiO(2) composite membrane in the redox flow cell. This paper presents results of the analysis of the Nafion-SiO(2) composite membrane used in a vanadium redox flow battery by nuclear magnetic resonance (NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier Transform Infra Red (FTIR) spectroscopy, and ultraviolet-visible spectroscopy. The XPS study reveals the chemical identity and environment of vanadium cations accumulated at the surface. On the other hand, the (19)F and (29)Si NMR measurement explores the nature of the interaction between the silica particles, Nafion side chains and diffused vanadium cations. The (29)Si NMR shows that the silica particles interact via hydrogen bonds with the sulfonic groups of Nafion and the diffused vanadium cations. Based on these spectroscopic studies, the chemical environment of the silica particles inside the Nafion membrane and their interaction with diffusing vanadium cations during flow cell operations are discussed. This study discusses the origin of performance degradation of the Nafion-SiO(2) composite membrane materials in vanadium redox flow batteries. Copyright © 2011 Elsevier Inc. All rights reserved.

Thermal radiative near field transport between vanadium dioxide and silicon oxide across the metal insulator transition

Energy Technology Data Exchange (ETDEWEB)

Menges, F.; Spieser, M.; Riel, H.; Gotsmann, B., E-mail: bgo@zurich.ibm.com [IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Dittberner, M. [IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Photonics Laboratory, ETH Zurich, 8093 Zurich (Switzerland); Novotny, L. [Photonics Laboratory, ETH Zurich, 8093 Zurich (Switzerland); Passarello, D.; Parkin, S. S. P. [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States)

2016-04-25

The thermal radiative near field transport between vanadium dioxide and silicon oxide at submicron distances is expected to exhibit a strong dependence on the state of vanadium dioxide which undergoes a metal-insulator transition near room temperature. We report the measurement of near field thermal transport between a heated silicon oxide micro-sphere and a vanadium dioxide thin film on a titanium oxide (rutile) substrate. The temperatures of the 15 nm vanadium dioxide thin film varied to be below and above the metal-insulator-transition, and the sphere temperatures were varied in a range between 100 and 200 °C. The measurements were performed using a vacuum-based scanning thermal microscope with a cantilevered resistive thermal sensor. We observe a thermal conductivity per unit area between the sphere and the film with a distance dependence following a power law trend and a conductance contrast larger than 2 for the two different phase states of the film.

Statistical analysis on hollow and core-shell structured vanadium oxide microspheres as cathode materials for Lithium ion batteries

Directory of Open Access Journals (Sweden)

Xing Liang

2018-06-01

Full Text Available In this data, the statistical analyses of vanadium oxide microspheres cathode materials are presented for the research article entitled “Statistical analyses on hollow and core-shell structured vanadium oxides microspheres as cathode materials for Lithium ion batteries” (Liang et al., 2017 [1]. This article shows the statistical analyses on N2 adsorption-desorption isotherm and morphology vanadium oxide microspheres as cathode materials for LIBs. Keywords: Adsorption-desorption isotherm, Pore size distribution, SEM images, TEM images

Medium carbon vanadium steels for closed die forging

International Nuclear Information System (INIS)

Jeszensky, Gabor; Plaut, Ronald Lesley

1993-01-01

This work analyses the medium carbon micro alloyed vanadium potential for closed die forged production. The steels reach the mechanical resistance requests during cooling after forging, eliminating the subsequent thermal treatment. Those steels also present good fatigue resistance and machinability. The industrial scale experiments are also reported

The extraction of vanadium pentoxide from waste of titanium tetrachloride by various methods

Directory of Open Access Journals (Sweden)

Инна Михайловна Гунько

2015-04-01

Full Text Available In article the recovery possibility of vanadium pentoxide from wastes, formed as a result of purification from impurities of technical titanium tetrachloride is researched. The purification from impurities is realized by different methods – pulp of lower titanium chlorides, hydrocarbonic reducer and cascade-rectifying purification. Usage of these purification methods leads to formation of anthropogenic wastes. The researches is shown that processing of these wastes is reasonable for the purpose of vanadium pentoxide extraction

Study of hydrogen isotopes super permeation through vanadium membrane on 'Prometheus' setup

International Nuclear Information System (INIS)

Musyaev, R. K.; Yukhimchuk, A. A.; Lebedev, B. S.; Busnyuk, A. O.; Notkin, M. E.; Samartsev, A. A.; Livshits, A. I.

2008-01-01

To develop the membrane pumping technology by means of superpermeable membranes at RFNC-VNIIEF in the 'Prometheus' setup, the experiments on superpermeation of hydrogen isotopes through metal membranes were carried out. The experimental results on superpermeation of thermal atoms of hydrogen isotopes including tritium through a cylindrical vanadium membrane are presented. The possibility of effective pumping, compression and recuperation of hydrogen isotopes by means of superpermeable membrane was demonstrated. The evaluation of membrane pumping rates and asymmetry degree of pure vanadium membrane was given. The work was performed under the ISTC-2854 project. (authors)

Vanadium oxide thin films deposited on silicon dioxide buffer layers by magnetron sputtering

International Nuclear Information System (INIS)

Chen Sihai; Ma Hong; Wang Shuangbao; Shen Nan; Xiao Jing; Zhou Hao; Zhao Xiaomei; Li Yi; Yi Xinjian

2006-01-01

Thin films made by vanadium oxide have been obtained by direct current magnetron sputtering method on SiO 2 buffer layers. A detailed electrical and structural characterization has been performed on the deposited films by four-point probe method and scanning electron microscopy (SEM). At room temperature, the four-point probe measurement result presents the resistance of the film to be 25 kU/sheet. The temperature coefficient of resistance is - 2.0%/K. SEM image indicates that the vanadium oxide exhibits a submicrostructure with lamella size ranging from 60 nm to 300 nm. A 32 x 32-element test microbolometer was fabricated based on the deposited thin film. The infrared response testing showed that the response was 200 mV. The obtained results allow us to conclude that the vanadium oxide thin films on SiO 2 buffer layers is suitable for uncooled focal plane arrays applications

Study of vanadium-based chemical conversion coating on the corrosion resistance of magnesium alloy

International Nuclear Information System (INIS)

Yang, K.H.; Ger, M.D.; Hwu, W.H.; Sung, Y.; Liu, Y.C.

2007-01-01

In this study, magnesium alloy (AZ61) was immersed in vanadium containing bath with various conditions, such as the vanadium concentration, immersion time and bath temperature. The results indicate that increase of both vanadium concentration and immersion time produces a thicker conversion layer. However, when immersion time is too long, it will worsen the corrosion resistance due to the increasing of the crack density. The experimental parameter of bath temperature has no significant effect on corrosion resistance. Our results demonstrated that the better corrosion resistance coating can be obtained when the samples are submitted to an immersion in the conversion bath containing NaVO 3 with concentration of 30 g l -1 for 10 min at 80 deg. C. The presented conversion treatment has its potential to replace the chrome-based conversion coating treatment

Temperature fluctuation effect on microstructural evolution of vanadium

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Hideo; Ochiai, Kenso; Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

1996-04-01

To compare the damage structure of vanadium and it`s alloy by irradiation at a constant and fluctuating temperature, the microstructure of samples irradiated by heavy ion were observed by an electron microscope. Pure vanadium (99.9%) from China was used as samples. After preparing the samples for the electron microscope, they are covered with Zr and Ta film, vacuum sealed and annealed for 2h at 1323K. Then the samples were irradiated by 3 MeV Cu ion of 0.75-100 dpa at 473-873K. Temperature was changed from low to high (473K/673K, 473K/873K, 673K/873K). On the irradiation experiments at constant temperature, the density of dislocation decreased with increasing temperature, but, more than 773K, the density became very low and the needle precipitation grown to <100> and void were observed. On the irradiation experiment at 673K/873K, the density of number of precipitation and void were decreased. (S.Y.)

Corrosion of vanadium and V 3Ti 1Si in flowing lithium

International Nuclear Information System (INIS)

Konys, J.

1986-01-01

A pumped Li loop fabricated from a titanium stabilized Type 316 steel was designed and constructed. At temperatures of about 823 K, experiments over a duration of more than 7500 h were performed. A magnetic trap had to be incorporated just before the flowmeter to avoid the precipitation of magnetic particles. Therefore it was possible to investigate the influence of the magnetic trap on the corrosion behaviour of V in flowing Li. The results are as follows: - The corrosion rate of V is about 14 μm/year and independent of the nitrogen content of Li. The corrosion rate of V 3Ti 1Si depends on the N concentration of Li. At about 30 wppm N in Li a vanadium-titanium-nitride is formed at the surface of the specimens. Hence, a low rate of 4 μm/year can be stated. - Both materials pick-up more N than C from Li, pure vanadium double as much nitrogen as the alloy V 3Ti 1Si. - N diffuses into the bulk of both materials, whilst C is bound near the surface. The hardening at the surface is due to the up-take of N. - The vanadium-carbonitride-, respectively the vanadium-titanium-nitride-layers have a strong influence on the weight loss and the up-take of non-metals. - The magnetic trap reduces the weight loss of vanadium in a significant way. The positive influence of the magnetic trap is supposed to be due to the reduction of the nitrogen content of Li. - The corrosion rates of the alloy V 3Ti 1Si show, that the dissolution due to V loss does not affect the lifetime of the alloy. The comparison with steels and nickle-base-alloys demonstrates the advantages of this material. Nevertheless, the purification of the Li and the control of its nonmetal-levels is indispensable. (orig./HP) [de

Energy efficiency of neptunium redox battery in comparison with vanadium battery

International Nuclear Information System (INIS)

Yamamura, T.; Watanabe, N.; Shiokawa, Y.

2006-01-01

A neptunium ion possesses two isostructural and reversible redox couples (Np 3+ /Np 4+ and NpO 2 + /NpO 2 2+ ) and is therefore suitable as an active material for a redox-flow battery. Since the plastic formed carbon (PFC) is known to show the largest k values for Np(IV)/Np(III) and Np(V)/Np(VI) reactions among various carbon electrodes, a cell was constructed by using the PFC, with the circulation induced by bubbling gas through the electrolyte. In discharge experiments with a neptunium and a vanadium battery using the cell, the former showed a lower voltage loss which suggests a smaller reaction overvoltage. Because of the high radioactivity of the neptunium, it was difficult to obtain sufficient circulation required for the redox-flow battery, therefore a model for evaluating the energy efficiency of the redox-flow battery was developed. By using the known k values for neptunium and vanadium electrode reactions at PFC electrodes, the energy efficiency of the neptunium battery was calculated to be 99.1% at 70 mA cm -2 , which exceeds that of the vanadium battery by ca. 16%

Wet sample digestion for quantification of vanadium(V) in serum by electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Heinemann, G.; Vogt, W.; Jacob, K.

1999-01-01

Three types of pressure digestion systems used prior to the determination of the ultratrace element vanadium by electrothermal atomic absorption spectrometry were evaluated: The high-pressure ashing (HPA) system, the DAB III pressure digestion system and the pressurized microwave digestion (PMD) system. Complete sample digestion and no loss of graphite tube sensitivity as well as reliable vanadium values could only be achieved with HPA digests of freeze-dried serum. The mean recovery rate was 98% and no loss of tube sensitivity could be observed. Using non-lyophilized serum the mean recovery rate was 70%. The DAB III digestion system, vicarious for closed pressure digestion in steel bombs with an allowable temperature up to about 200C, cannot be recommended to mineralize human biological material for vanadium determinations, because the remaining not completely decomposed organic compounds extracted together with the vanadium-cupferron complex caused a marked carbon-buildup and formation of carbides in the graphite tube were found to change the shape of the absorption signals distinctly, and to decline the tube sensitivity strongly (about 25%) so that reliable results cannot be achieved. The recovery rate was too low in general (about 50%). In addition, a subsequent treatment of the DAB III digests with perchloric acid was unsuccessful. The PMD system proved to be not suited, because the samples became highly contaminated by vanadium possibly from the titan seal. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Corrosion resistance investigation of vanadium alloys in liquid lithium

Energy Technology Data Exchange (ETDEWEB)

Borovitskaya, I. V., E-mail: symp@imet.ac.ru [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation); Lyublinskiy, I. E. [JSC Red Star (Russian Federation); Bondarenko, G. G. [National Research University Higher School of Economics (Russian Federation); Paramonova, V. V. [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation); Korshunov, S. N.; Mansurova, A. N. [National Research Center Kurchatov Institute (Russian Federation); Lyakhovitskiy, M. M. [Russian Academy of Sciences, Baikov Institute of Metallurgy and Materials Science (Russian Federation); Zharkov, M. Yu. [JSC Red Star (Russian Federation)

2016-12-15

A major concern in using vanadium alloys for first wall/blanket systems in fusion reactors is their activity with regard to nonmetallic impurities in the coolants. This paper presents the results of studying the corrosion resistance in high-purity liquid lithium (with the nitrogen and carbon content of less than 10{sup –3} wt %) of vanadium and vanadium alloys (V–1.86Ga, V–3.4Ga–0.62Si, V–4.81Ti–4.82Cr) both in the initial state and preliminarily irradiated with Ar+ ions with energy of 20 keV to a dose of 10{sup 22} m{sup –2} at an irradiation temperature of ~400°C. The degree of corrosion was estimated by measuring the changes in the weight and microhardness. Corrosion tests were carried out under static isothermal conditions at a temperature of 600°C for 400 h. The identity of corrosion mechanisms of materials both irradiated with Ar ions and not irradiated, which consisted in an insignificant penetration of nitrogen into the materials and a substantial escape of oxygen from the materials, causing the formation of a zone with a reduced microhardness near the surface, was established. The influence of the corrosive action of lithium on the surface morphology of the materials under study was found, resulting in the manifestation of grain boundaries and slip lines on the sample surface, the latter being most clearly observed in the case of preliminary irradiation with Ar ions.

Tensile properties of commercially pure vanadium from room temperature to 1200 degree C

International Nuclear Information System (INIS)

Henshall, G.A.; Torres, S.G.

1993-12-01

The tensile properties of vanadium are sensitive to interstitial impurity content, on grain size and strain rate. Thus, it is problematic to use published tensile data for materials potentially varying in these quantities. This investigation was undertaken to fully characterize the tensile properties of the commercially pure vanadium used at Lawrence Livermore. Both sheet and rod stock were tested in vacuum from ambient temperature to 1200C at strain rates 6.67 x 10 -5 to 6.67 x 10 -2 s -1 . The results of these experiments show that vanadium behaves in a manner typical of many bcc metals containing interstitial impurities. Local peaks in yield stress and ultimate tensile stress vs temperature curves are observed at intermediate temperatures. Serrated yielding also is observed in some temperature ranges. Changes in strain rate within the quasi-static regime have a relatively small, predictable effect. The rod and sheet stock have similar properties, except that the lower yield stress of the rod is less than that of the sheet over most of the temperature range studied. No plateau in yield strength vs temperature curve was observed for the rod. In both forms, and for all temperatures, vanadium is ductile. The elongation to failure reaches a minimum of approximately 35% at a temperature of 500C and a maximum of approximately 140% at 1200C

Temperature Dependence of Uranium and Vanadium Adsorption on Amidoxime-Based Adsorbents in Natural Seawater

Energy Technology Data Exchange (ETDEWEB)

Kuo, Li-Jung [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Gill, Gary A. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Tsouris, Costas [Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Rao, Linfeng [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow ID 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow ID 83844 USA; Janke, Christopher J. [Oak Ridge National Laboratory, Oak Ridge TN 37831 USA; Strivens, Jonathan E. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Wood, Jordana R. [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; Schlafer, Nicholas [Marine Sciences Laboratory, Pacific Northwest National Laboratory, Sequim WA 98382 USA; D' Alessandro, Evan K. [Rosensteil School of Marine and Atmospheric Chemistry, University of Miami, Miami FL 33149 USA

2018-01-16

The apparent enthalpy and entropy of the complexation of uranium (VI) and vanadium (V) with amidoxime ligands grafted onto polyethylene fiber was determined using time series measurements of adsorption capacities in natural seawater at three different temperatures. The complexation of uranium was highly endothermic, while the complexation of vanadium showed minimal temperature sensitivity. Amidoxime-based polymeric adsorbents exhibit significantly increased uranium adsorption capacities and selectivity in warmer waters.

Six-coordinate oxo-vanadium(V) dimer complex with methoxy bridging: synthesis, crystal structure, biological activity and molecular docking

Czech Academy of Sciences Publication Activity Database

Heidari, F.; Fatemi, S.J.A.; Yousef Ebrahimipour, S.; Ebrahimnejad, H.; Castro, J.; Dušek, Michal; Eigner, Václav

2017-01-01

Roč. 76, Feb (2017), s. 1-4 ISSN 1387-7003 R&D Projects: GA MŠk(CZ) LO1603; GA ČR(CZ) GA14-03276S EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : oxo-vanadium(V) * Schiff base complex * antimicrobial activity * X-ray crystal structure Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.640, year: 2016

Isotope mixtures of hydrogen in vanadium

International Nuclear Information System (INIS)

Mecking-Schloetensack, P.

1982-03-01

The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

Vanadium levels in marine organisms of Onagawa Bay in Japan

International Nuclear Information System (INIS)

Fukushima, M.; Suzuki, H.; Saito, K.; Chatt, A.

2009-01-01

Vanadium in marine organisms from Onagawa Bay in Miyagi, Japan, was determined by an instrumental neutron activation analysis (INAA) method using anticoincidence gamma-ray spectrometry at the Dalhousie University SLOWPOKE-2 Reactor (DUSR) facility in Canada. Seaweeds, cultivated oysters, plankton, and four different species of sea squirt were collected from Onagawa Bay during 2005-2008. Vanadium levels around 20 μg g -1 (dry weight) were found in Japanese tangle and hijiki seaweeds. One species of sea squirt (Ciona savignyi) contained 160-500 ppm of V and it was highest among the four species of sea squirts studied. Protein-bound V species were separated by gel permeation chromatography (GPC) and the element determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). (author)

Recent Development of Nanocomposite Membranes for Vanadium Redox Flow Batteries

Directory of Open Access Journals (Sweden)

Sang-Ho Cha

2015-01-01

Full Text Available The vanadium redox flow battery (VRB has received considerable attention due to its long cycle life, flexible design, fast response time, deep-discharge capability, and low pollution emissions in large-scale energy storage. The key component of VRB is an ion exchange membrane that prevents cross mixing of the positive and negative electrolytes by separating two electrolyte solutions, while allowing the conduction of ions. This review summarizes efforts in developing nanocomposite membranes with reduced vanadium ion permeability and improved proton conductivity in order to achieve high performance and long life of VRB systems. Moreover, functionalized nanocomposite membranes will be reviewed for the development of next-generation materials to further improve the performance of VRB, focusing on their properties and performance of VRB.

Vanadia supported on zeolites for SCR of NO by ammonia

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Riisager, Anders; Fehrmann, Rasmus

2010-01-01

, acidity and micropore structure of the support. Apparently the support hosted the potassium oxide on the acid sites, thereby protecting the active vanadium species from poisoning. Zeolite based catalysts might therefore prove useful for SCR of NO in alkali-containing flue gases from, e.g. biomass fired...

The rapid spectrophotometric determination of vanadium in tool steel with 9(6-methyl-2-pyridyl)azo5

International Nuclear Information System (INIS)

Beaupre, P.W.; Holland, W.J.

1980-01-01

An extractive-spectrophotometric method for the determination of vanadium in tool steel is described. The only sample pretreatment required is dissolution. An average vanadium of 2.06% was obtained on a standard sample compared to the recommended value of 2.06%. (author)

Determination of vanadium in titanate-based ferroelectrics by INAA with discriminating gamma-ray spectrometry

Czech Academy of Sciences Publication Activity Database

Kameník, Jan; Dragounová, K.; Kučera, Jan; Bryknar, Z.; Trepakov, Vladimír; Strunga, Vladimír

2017-01-01

Roč. 311, č. 2 (2017), s. 1333-1338 ISSN 0236-5731. [1st International Conference on Radioanalytical and Nuclear chemistry (RANC). Budapest, 10.04.2016-15.04.2016] R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2015056 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : Titanate-based ferroelectrics * Vanadium * INAA * discriminating gamma-ray spectrometry Subject RIV: CB - Analytical Chemistry, Separation; BM - Solid Matter Physics ; Magnetism (FZU-D) OBOR OECD: Analytical chemistry; Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D) Impact factor: 1.282, year: 2016

Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

Energy Technology Data Exchange (ETDEWEB)

Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

1998-12-31

Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

Vanadium oxide thin films and fibers obtained by acetylacetonate sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Berezina, O.; Kirienko, D. [Department of Physical Engineering, Petrozavodsk State University, 185910 Petrozavodsk (Russian Federation); Pergament, A., E-mail: aperg@psu.karelia.ru [Department of Physical Engineering, Petrozavodsk State University, 185910 Petrozavodsk (Russian Federation); Stefanovich, G.; Velichko, A. [Department of Physical Engineering, Petrozavodsk State University, 185910 Petrozavodsk (Russian Federation); Zlomanov, V. [Department of Chemistry, Moscow State University, 119991 Moscow (Russian Federation)

2015-01-01

Vanadium oxide films and fibers have been fabricated by the acetylacetonate sol–gel method followed by annealing in wet nitrogen. The samples are characterized by X-ray diffraction and electrical conductivity measurements. The effects of a sol aging, the precursor decomposition and the gas atmosphere composition on the annealing process, structure and properties of the films are discussed. The two-stage temperature regime of annealing of amorphous films in wet nitrogen for formation of the well crystallized VO{sub 2} phase is chosen: 1) 25–550 °C and 2) 550–600 °C. The obtained films demonstrate the metal–insulator transition and electrical switching. Also, the effect of the polyvinylpyrrolidone additive concentration and electrospinning parameters on qualitative (absence of defects and gel drops) and quantitative (length and diameter) characteristics of vanadium oxide fibers is studied. - Highlights: • Vanadium oxide thin films and fibers are synthesized by sol–gel method. • The effect of annealing, atmosphere, time and electrospinning parameters is studied. • Produced VO{sub 2} structures exhibit metal–insulator transition and electrical switching.

Recovery of Vanadium from H2SO4-HF Acidic Leaching Solution of Black Shale by Solvent Extraction and Precipitation

Directory of Open Access Journals (Sweden)

Xingbin Li

2016-03-01

Full Text Available The recovery of vanadium from sulfuric and hydrofluoric mixed acid solutions generated by the direct leaching of black shale was investigated using solvent extraction and precipitation methods. The process consisted of reduction, solvent extraction, and stripping, followed by precipitation and calcination to yield vanadium pentoxide. The influence of various operating parameters on the extraction and recovery of vanadium was studied. Vanadium (IV was selectively extracted using a mixture of 10% (v/v di(2-ethylhexylphosphoric acid and 5% (v/v tri-n-butylphosphate in sulfonated kerosene. Using six extraction and five stripping stages, the extraction efficiency for vanadium was 96.7% and the stripping efficiency was 99.7%. V2O5 with a purity of 99.52% was obtained by oxidation of the loaded strip solution and precipitation of ammonium polyvanadate at pH 1.8 to 2.2, followed by calcination of the dried precipitate at 550 °C for 2 h. It was concluded that the combination of solvent extraction and precipitation is an efficient method for the recovery of vanadium from a multi-element leach solution generated from black shale.

Determination of macro nickel, vanadium and iron in crude oil and residues by derivative spectrophotometry

International Nuclear Information System (INIS)

Liu, W.; Wang, L.; Li, X.

1992-01-01

In this paper, a new method with derivative spectrophotometry and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol as the chromogenic reagent in buffer solution of different pH developed for determining micro amounts of nickel. Vanadium and iron in crude oil and residues is reported. Forth-, Second- and Third-, Fourth-order derivative spectrophotometry were applied to determine nickel, nickel and vanadium, nickel and iron in crude oil and residues, respectively. The derivative maximums chosen for the measurement were at 556 nm for nickel, 540 nm and 643 nm for nickel and vanadium, 524 nm and 604 nm for nickel and iron. Beer's law is valid for the range 1.0 x 10 -6 to 2.5 x 10 -5 M

Atmospheric pressure chemical vapour deposition of the nitrides and oxynitrides of vanadium, titanium and chromium

International Nuclear Information System (INIS)

Elwin, G.S.

1999-01-01

A study has been made into the atmospheric pressure chemical vapour deposition of nitrides and oxynitrides of vanadium, titanium and chromium. Vanadium tetrachloride, vanadium oxychloride, chromyl chloride and titanium tetrachloride have been used as precursors with ammonia, at different flow conditions and temperatures. Vanadium nitride, vanadium oxynitride, chromium oxynitride, titanium/vanadium nitride and titanium/chromium oxynitride have been deposited as thin films on glass. The APCVD reaction of VCl 4 and ammonia leads to films with general composition VN x O y . By raising the ammonia concentration so that it is in excess (0.42 dm 3 min -1 VCl 4 with 1.0 dm 3 min -1 NH 3 at 500 deg. C) a film has been deposited with the composition VN 0.8 O 0.2 . Further investigation discovered similar elemental compositions could be reached by deposition at 350 deg. C (0.42 dm 3 min -1 VCl 4 with 0.5 dm 3 min -1 NH 3 ), followed by annealing at 650 deg. C, and cooled under a flow of ammonia. Only films formed below 400 deg. C were found to contain carbon or chlorine ( 3 and ammonia also lead to films of composition VN x O y the oxygen to nitrogen ratios depending on the deposition conditions. The reaction Of VOCl 3 (0.42 dm 3 min -1 ) and ammonia (0.2 dm 3 min -1 ) at 500 deg. C lead to a film of composition VN 0. 47O 1.06 . The reaction of VOCl 3 (0.42 dm 3 min -1 ) and ammonia (0.5 dm 3 min -1 ) at 650 deg. C lead to a film of composition VN 0.63 O 0.41 . The reaction of chromyl chloride with excess ammonia led to the formation of chromium oxide (Cr 2 O 3 ) films. Mixed metal films were prepared from the reactions of vanadium tetrachloride, titanium tetrachloride and ammonia to prepare V x Ti y N z and chromyl chloride, titanium tetrachloride and ammonia to form TiCr x O y N z . Both reactions produced the intended mixed coating but it was found that the vanadium / titanium nitride contained around 10 % vanadium whatever the conditions used. Oxygen contamination

Theoretical Study of Terminal Vanadium(V Chalcogenido Complexes Bearing Chlorido and Methoxido Ligands

Directory of Open Access Journals (Sweden)

Samuel Tetteh

2017-01-01

Full Text Available Solvent (methanol coordinated vanadium(V chalcogenido complexes bearing chlorido and methoxido ligands have been studied computationally by means of density functional (DFT methods. The gas phase complexes were fully optimized using B3LYP/GEN functionals with 6-31+G⁎⁎ and LANL2DZ basis sets. The optimized complexes show distorted octahedral geometries around the central vanadium atom. The ligand pπ-vanadium dπ interactions were analyzed by natural bond order (NBO and natural population analyses (NPA. These results show strong stabilization of the V=O bond as was further confirmed by the analyses of the frontier molecular orbitals (FMOs. Second-order perturbation analyses also revealed substantial delocalization of lone pair electrons from the oxido ligand into vacant non-Lewis (Rydberg orbitals as compared to the sulfido and seleno analogues. These results show significant ligand-to-metal charge transfer (LMCT interactions. Full interaction map (FIM of the reference complex confirms hydrogen bond interactions involving the methanol (O-H and the chlorido ligand.

The toxicity of vanadium on gastrointestinal, urinary and reproductive system, and its influence on fertility and fetuses malformations

Directory of Open Access Journals (Sweden)

Aleksandra Wilk

2017-09-01

Additionally, this research identifies the doses of vanadium which lead to pathological alterations becoming visible within tissues. Moreover, this study includes information about the protective efficacy of some substances in view of the toxicity of vanadium.

Potentiometric titrations of molybdenum and vanadium in aqueous and mixed so lvents

International Nuclear Information System (INIS)

Das, S.K.; Dhaneshwar, R.G.

1990-01-01

Potentiometric titration method was developed for molybdenum, employing different electrode systems. Molybdenum(VI) is reduced to molybdenum(V) by ferrous solution in presence of phosphoric acid and then titrated with potassium dichromate. It was found that ferrous concentration should be five times more than molybdenum and phosphoric acid should be 1.0 ml for 0.1N titration and 0.5 ml for lower concentration titrations. The method is also applicable to vanadium titrations. Employing Au/SCE and Pt/SCE systems, it was observed that generally curve heights obtained for platinum electrode are higher than those for gold electrode. Also for both the electrode systems, the curve heights for vanadium titrations were found to be more than those for molybdenum. Lower limits of titrations for Au/SCE system are 0.01N for molybdenum and 0.0001N for vanadium, whereas for Pt/SCE system, the lower limits obtained were 0.01N for both molybdenum and vanadium titrations. In order to improve the sensitivities of the method, the bimetallic electrode systems Au/Pt and Pt/Au were employed. Au/Pt system was found to give better results than Pt/Au systems. Addition of organic solvent was found to have beneficial effects for titrations of 0.001N and below. Methanol was found to be a better solvent than ethanol. Molybdenum titrations, at 0.0001N level could be performed in methanol with Au/Pt system, which is to b e generally preferred than Pt/Au system. (author). 7 refs., 3 tabs

Removal and Adsorption of Vanadium and Boron by Some Egyptian Clay Sediments

International Nuclear Information System (INIS)

Mahdy, R.M.

2016-01-01

Due to the increase concerns of the environmental pollution problems, to have safer environment, it seems so important to propose an effective exploration of geological barriers, which are suitable for waste materials disposal. In fact, clay sediments play an essential role as natural adsorbents to immobilize nuclear elements contaminates such as uranium, vanadium and boron. In this study, the clay sediments was collected from either clay exploitation localities or from nearby radioactive mineralization provinces in Egypt. The obtained data clarifies that the adsorption of vanadium and boron by clay sediments were increased by increasing the initial concentration of vanadium and boron The adsorption maxima (B) for vanadium in kaolin samples namely Mossaba Salama, El Teah and EL Eessala reached 71.4, 66.7 and 47.6). On the other hand, the adsorption maxima (B) in bentonite samples namely North Coast – H ( El Sahel el shamaly) (high viscosity) followed by North Coast (El Sahel el shamaly) then North Coast (El Sahel el shamaly) (low viscosity) and finally Kasr El Sagha reached 135.1, 79.4, 61.5 and 47.6 respectively.The adsorption maxima for boron in kaolinite samples namely Mossaba Salama, El Teah and EL Eessala reached 47.5, 30.6 and 27.0 while in the bentonite samples it was arranged from Kaser El Sagha (35.7), North Coast (H) El Sahel el shamaly ( H) (32.3), North Coast (L) (27.9) ( El Sahel el shamaly L) to North Coast (El Sahel el shamaly) (3.5)

Formation of electrically insulating coatings on aluminided vanadium-base alloys in liquid lithium

International Nuclear Information System (INIS)

Park, J.H.; Dragel, G.

1993-01-01

Aluminide coatings were produced on vanadium and vanadium-base alloys by exposure of the materials to liquid lithium that contained 3-5 at.% dissolved aluminum in sealed capsules at temperatures between 775 and 880 degrees C. Reaction of the aluminide layer with dissolved nitrogen in liquid lithium provides a means of developing an in-situ electrical insulator coating on the surface of the alloys. The electrical resistivity of A1N coatings on aluminided V and V-20 wt.% Ti was determined in-situ

Locations of oxygen, nitrogen and carbon atoms in vanadium determined by neutron diffraction

International Nuclear Information System (INIS)

Hiraga, K.; Onozuka, T.; Hirabayashi, M.

1977-01-01

The occupation sites of oxygen, nitrogen, and carbon atoms dissolved interstitially in vanadium have been determined by means of neutron diffraction with use of single crystals of VOsub(0.032), VNsub(0.013) and VCsub(0.006). It is revealed that the interstitial atoms occupy, randomly, the octahedral sites in the b.c.c. host lattice of the three crystals. Neutron diffraction is advantageous for the present purpose, since the coherent scattering amplitudes of the solute atoms are much larger than that of the vanadium atom. (Auth.)

Raman and XPS characterization of vanadium oxide thin films with temperature

Energy Technology Data Exchange (ETDEWEB)

Ureña-Begara, Ferran, E-mail: ferran.urena@uclouvain.be [Université catholique de Louvain, Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Louvain-la-Neuve (Belgium); Crunteanu, Aurelian [XLIM Research Institute, UMR 7252, CNRS/Université de Limoges, Limoges (France); Raskin, Jean-Pierre [Université catholique de Louvain, Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Louvain-la-Neuve (Belgium)

2017-05-01

Highlights: • Comprehensive study of the oxidation of VO{sub 2} thin films from R.T. up to 550 °C. • Phase changes and mixed-valence vanadium oxides formed during the oxidation process. • Reported Raman and XPS signatures for each vanadium oxide. • Monitoring of the current and resistance evolution at the surface of the films. • Oxidation model describing the evolution of the vanadium oxides and phase changes. - Abstract: The oxidation mechanisms and the numerous phase transitions undergone by VO{sub 2} thin films deposited on SiO{sub 2}/Si and Al{sub 2}O{sub 3} substrates when heated from room temperature (R.T.) up to 550 °C in air are investigated by Raman and X-ray photoelectron spectroscopy. The results show that the films undergo several intermediate phase transitions between the initial VO{sub 2} monoclinic phase at R.T. and the final V{sub 2}O{sub 5} phase at 550 °C. The information about these intermediate phase transitions is scarce and their identification is important since they are often found during the synthesis of vanadium dioxide films. Significant changes in the film conductivity have also been observed to occur associated to the phase transitions. In this work, current and resistance measurements performed on the surface of the films are implemented in parallel with the Raman measurements to correlate the different phases with the conductivity of the films. A model to explain the oxidation mechanisms and phenomena occurring during the oxidation of the films is proposed. Peak frequencies, full-width half-maxima, binding energies and oxidation states from the Raman and X-ray photoelectron spectroscopy experiments are reported and analyzed for all the phases encountered in VO{sub 2} films prepared on SiO{sub 2}/Si and Al{sub 2}O{sub 3} substrates.

Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

International Nuclear Information System (INIS)

Schacht, L.; Navarrete, J.; Schacht, P.; Ramirez, M. A.

2010-01-01

V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

Influence of vanadium oxidation states on the performance of V-Mg-Al mixed-oxide catalysts for the oxidative dehydrogenation of propane

Energy Technology Data Exchange (ETDEWEB)

Schacht, L. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Ciencia de Materiales, Av. IPN s/n, Edificio 9, Col. Lindavista, 07738 Mexico D. F. (Mexico); Navarrete, J.; Schacht, P.; Ramirez, M. A., E-mail: pschacha@imp.m [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas No. 152, 07730 Mexico D. F. (Mexico)

2010-07-01

V-Mg-Al mixed-oxide catalysts for oxidative dehydrogenation of propane were prepared by thermal decomposition of Mg-Al-layered double hydroxides with vanadium interlayer doping. The obtained catalysts were tested for the oxidative dehydrogenation of propane, obtaining good results in catalytic activity (conversion 16.55 % and selectivity 99.97 %) Results indicated that catalytic performance of these materials depends on how vanadium is integrated in the layered structure, which is determined by the Mg/Al ratio. Vanadium interlayer doping modifies the oxidation state of vanadium and consequently catalytic properties. Surface properties were studied by X-ray photoelectron spectroscopic and diffuse reflectance, UV-visible spectroscopy, and temperature programmed reduction. The analyses provided information about the oxidation state, before and after the reaction. From these results, it is suggested that selectivity to propylene and catalytic activity depend mainly of vanadium oxidation state. (Author)

Spectrophotometric investigation of vanadium(4) complexing with monoamine complexones

International Nuclear Information System (INIS)

Merkulov, D.A.; Kornev, V.I.

1998-01-01

Interaction of vanadium(4) with iminodiacetic (H 2 Ida) and methyliminodiacetic (H 2 Mida) acids by μ = 0.1 (NaClO 4 ) and t = 20±2 deg C is studied through the spectrophotometric method. It is established that the process of complex formation in quasi-binary systems due to competitive effect of hydroxide ions depends to a large degree on the ligands concentration and properties. The VOIda, VO(OH)Ida - , VOMida, VO(OH)Mida - complexes are identified. The stability constants logarithms of these complexes are equal correspondingly to 9.81±0.02, 18.19±0.03, 10.15±0.03, 18.34±0.02. The results of the study on the VO 2+ -HIda and VO 2+ -H 2 Mida systems agree well with the regularities, identified by the study on the vanadium(4) complex formation with other complexones of the iminodiacetate series

Mechanisms of Vanadium Recovery from Stone Coal by Novel BaCO3/CaO Composite Additive Roasting and Acid Leaching Technology

Directory of Open Access Journals (Sweden)

Zhenlei Cai

2016-03-01

Full Text Available In this report, the vanadium recovery mechanisms by novel BaCO3/CaO composite additive roasting and acid leaching technology, including the phase transformations and the vanadium leaching kinetics, were studied. The purpose of this manuscript is to realize and improve the vanadium recovery from stone coal using BaCO3/CaO as the composite additive. The results indicated that during the composite additive BaCO3/CaO roasting process, the monoclinic crystalline structure of muscovite (K(Al,V2[Si3AlO10](OH2 was converted into the hexagonal crystalline structure of BaSi4O9 and the tetragonal crystalline structure of Gehlenite (Ca2Al2SiO7, which could, therefore, facilitate the release and extraction of vanadium. Vanadium in leaching residue was probably in the form of vanadate or pyrovanadate of barium and calcium, which were hardly extracted during the sulfuric acid leaching process. The vanadium leaching kinetic analysis indicated that the leaching process was controlled by the diffusion through a product layer. The apparent activation energy could be achieved as 46.51 kJ/mol. The reaction order with respect to the sulfuric acid concentration was 1.1059. The kinetic model of vanadium recovery from stone coal using novel composite additive BaCO3/CaO could be finally established.

Controlled synthesis and electrochemical properties of vanadium ...

Indian Academy of Sciences (India)

Vanadium oxides (V3O7·H2O and VO2) with different morphologies have been selectively synthesized ... appeared at around 68 ◦C. Furthermore, the electrochemical properties of V3O7·H2O nanobelts, VO2(B) .... morphologies of shape-controlled orthorhombic V3O7·H2O ..... condition, as shown in figures S14i and j.

One-step preparation and photocatalytic performance of vanadium doped TiO{sub 2} coatings

Energy Technology Data Exchange (ETDEWEB)

Vasilić, R., E-mail: rastko.vasilic@ff.bg.ac.rs [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Stojadinović, S. [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Radić, N. [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Stefanov, P. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Dohčević-Mitrović, Z. [University of Belgrade, Institute of Physics, Pregrevica 118, 11080 Belgrade (Serbia); Grbić, B. [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia)

2015-02-01

In this paper, we have investigated one-step preparation of vanadium doped TiO{sub 2} coatings formed by plasma electrolytic oxidation (PEO) of titanium in electrolyte containing 10 g/L Na{sub 3}PO{sub 4}·12H{sub 2}O + 0.5 g/L NH{sub 4}VO{sub 3}. The morphology, phase structure, and elemental composition of the formed coatings were characterized by atomic force microscopy (AFM), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) techniques. Ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS) was employed to evaluate the band gap energy of obtained coatings. Vanadium doped TiO{sub 2} coatings are partly crystallized and mainly composed of anatase phase TiO{sub 2}, with up to about 2 wt% of vanadium present in the surface layer of the oxide. The valence band photoelectron spectra and UV–Vis DRS showed that vanadium doped TiO{sub 2} coatings exhibit notable red shift with respect to the pure TiO{sub 2} coatings. The photocatalytic activity was evaluated by monitoring the degradation of methyl orange under simulated sunlight conditions. Photocatalytic activity of vanadium doped TiO{sub 2} coatings increases with PEO time. Prolonged PEO times result in higher roughness of obtained coatings, thus increasing surface area available for methyl orange degradation. Vanadium doped TiO{sub 2} coatings obtained after 180 s of PEO time exhibit the best photocatalytic activity and about 67% of methyl orange is degraded after 12 h of irradiation under simulated sunlight. - Highlights: • One-step preparation of V-doped TiO{sub 2} coatings in 10 g/L Na{sub 3}PO{sub 4}·12H{sub 2}O + 0.5 g/L NH{sub 4}VO{sub 3}. • Properties of obtained coatings strongly depend on microdischarge characteristics. • Band gap of V-doped TiO{sub 2} coatings is shifted towards red side of the spectrum. • V-doped TiO{sub 2} coatings have better photocatalytic activity than pure TiO{sub 2}. • After 12 h of simulated sunlight irradiation, 67% of

Preparation and characterization of phosphate glasses containing titanium and vanadium

Energy Technology Data Exchange (ETDEWEB)

Kaoua, S. [Laboratoire de Chimie du Solide, Faculte des Sciences Ain Chock, Casablanca (Morocco); Krimi, S. [Laboratoire de Chimie du Solide, Faculte des Sciences Ain Chock, Casablanca (Morocco)]. E-mail: krimisaida@yahoo.fr; El Jazouli, A. [Laboratoire de Chimie des Materiaux Solides, Faculte des Sciences Ben M' Sik, Casablanca (Morocco); Hlil, E.K. [Laboratoire de Cristallographie du CNRS, Grenoble (France)]. E-mail: hlil@grenoble.cnrs.fr; Waal, D. de [Department of Chemistry, University of Pretoria, 0002 Pretoria (South Africa)

2007-02-21

Na{sub 5-x}Ti{sub 1-x}V {sub x}(PO{sub 4}){sub 3} (0 {<=} x {<=} 1) phosphates glasses have been obtained in air by direct fusion of Na{sub 2}CO{sub 3}, TiO{sub 2}, V{sub 2}O{sub 5} and (NH{sub 4}){sub 2}HPO{sub 4}. Vitreous Na{sub 5}Ti(PO{sub 4}){sub 3} is colourless while the glasses containing vanadium are green, due to the reduction of V{sup 5+} to V{sup 4+}. Glass transition and crystallization temperatures (T {sub g}, T {sub c}) decrease when the amount of vanadium increases. EPR, Raman and UV-vis spectra have been investigated. The results are consistent with the presence of V{sup 4+} ions in distorted octahedra with very strong V-O bond.

Non-isothermal modelling of the all-vanadium redox flow battery

International Nuclear Information System (INIS)

Al-Fetlawi, H.; Shah, A.A.; Walsh, F.C.

2009-01-01

An non-isothermal model for the all-vanadium redox flow battery (RFB) is presented. The two-dimensional model is based on a comprehensive description of mass, charge, energy and momentum transport and conservation, and is combined with a global kinetic model for reactions involving vanadium species. Heat is generated as a result of activation losses, electrochemical reaction and ohmic resistance. Numerical simulations demonstrate the effects of changes in the operating temperature on performance. It is shown that variations in the electrolyte flow rate and the magnitude of the applied current substantially alter the charge/discharge characteristics, the temperature rise and the distribution of temperature. The influence of heat losses on the charge/discharge behaviour and temperature distribution is investigated. Conditions for localised heating and membrane degradation are discussed.

Additive for vanadium and sulfur oxide capture in catalytic cracking

International Nuclear Information System (INIS)

Chin, A.A.; Sapre, A.V.; Sarli, M.S.

1991-01-01

This patent describes a fluid catalytic cracking process in which a hydrocarbon feedstock. It comprises: a vanadium contaminant in an amount of a least 2 ppmw is cracked under fluid catalytic cracking conditions with a solid, particulate cracking catalyst to produce cracking products of lower molecular weight while depositing carbonaceous material on the particles of cracking catalyst, separating the particles of cracking catalyst from the cracking products in the disengaging zone and oxidatively regenerating the cracking catalyst by burning off the deposited carbonaceous material in a regeneration zone, the improvement comprising reducing the make-up rate of the cracking catalyst by contacting the cracking feed with a particulate additive composition for passivating the vanadium content of the feed, comprising an alkaline earth metal oxide and an alkaline earth metal spinel

Synthesis of vanadium trioxide

International Nuclear Information System (INIS)

Yankelevich, R.G.; Vinarov, I.V.; Sheka, I.A.; Pushek, N.G.

1976-01-01

There have been studied the conditions for production of vanadium trioxide in a single-stage process of V 2 O 5 reduction by gaseous ammonia. To determine the optimum conditions for V 2 O 5 reduction, there have been studied the temperature range of the reaction and the effect offered by the volumetric rate and time of ammonia injection. The following conditions have proved to be the optimum ones: temperature - 450 deg C, volumetric rate of NH 3 injection at a batch of 10 g - 4 l/h, time of recovery - 3 hours. In accordance with the adopted procedure there have been synthetized the samples containing 98 - 99% V 2 O 3 [ru

Long-term performance of the CANDU-type of vanadium self-powered neutron detectors in NRU

Energy Technology Data Exchange (ETDEWEB)

Leung, T.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]. E-mail: leungt@aecl.ca

2007-07-01

The CANDU-type of in-core vanadium self-powered neutron flux detectors have been installed in NRU to monitor the axial neutron flux distributions adjacent to the loop fuel test sites since 1996. This paper describes how the thermal neutron fluxes were measured at two monitoring sites, and presents a method of correcting the vanadium burn-up effect, which can be up to 2 to 3% per year, depending on the detector locations in the reactor. It also presents the results of measurements from neutron flux detectors that have operated for over eight-years in NRU. There is good agreement between the measured and simulated neutron fluxes, to within {+-} 6.5%, and the long-term performance of the CANDU-type of vanadium neutron flux detectors in NRU is satisfactory. (author)

Importance of Vanadium-Catalyzed Oxidation of SO2to SO3in Two-Stroke Marine Diesel Engines

DEFF Research Database (Denmark)

Colom, Juan M.; Alzueta, María U.; Christensen, Jakob Munkholt

2016-01-01

Low-speed marine diesel engines are mostly operated on heavy fuel oils, which have a high content of sulfur andash, including trace amounts of vanadium, nickel, and aluminum. In particular, vanadium oxides could catalyze in-cylinderoxidation of SO2 to SO3, promoting the formation of sulfuric acid...

Improving the submicro determination of vanadium in natural water using primary-secondary wavelength spectrophotometry

International Nuclear Information System (INIS)

Khongven Gao

1999-01-01

In acidic solution and in the presence of ammonium persulfate, the conventional reaction of vanadium(5) with gallic acid to form an orange complex has been used for the improvement of the determination of trace amounts of vanadium in water by the updated method named primary-secondary wavelength spectrophotometry. The results show that the analytical precision and accuracy were improved and gave higher determination sensitivity than ordinary spectrophotometry. The relative standard deviations were less than 5.6 % [ru

Proceedings of the 2. workshop on vanadium alloy development for fusion

International Nuclear Information System (INIS)

Osch, E.V. van

1996-10-01

From 20 to 22 May 1996 the Second IEA Vanadium Alloy Development for Fusion Workshop was held at the Netherlands Energy Research Foundation, ECN in Petten. Twenty three experts from the European Union, Japan, the Russian Federation and the United States exchanged results and analyses of completed experiments and discussed the program planning. The manufacturing of half-finished products and the optimization of subsequent heat treatments were presented and discussed in the first session. The problems and solutions to joining vanadium alloy half-finished products by welding and brazing have been addressed in another session. Corrosion and compatibility properties have been evaluated in a different session together with coating requirements. Several sessions were devoted to the effects of radiation on the mechanical properties, especially toughness, of vanadium alloys. Also the role of the transmutation product helium, in particular its introduction into specimens, was evaluated. The respective plans of the four parties for continuation of the ongoing research and development programs have been discussed with the emphasis on avoiding duplications in the area of radiation experiments. The critical issues were identified and the related priorities discussed in the time frame set by the schedule for the building of ITER test modules and with the long term DEMO requirements in mind. (orig.)

Proceedings of the 2. workshop on vanadium alloy development for fusion

Energy Technology Data Exchange (ETDEWEB)

Osch, E.V. van [ed.

1996-10-01

From 20 to 22 May 1996 the Second IEA Vanadium Alloy Development for Fusion Workshop was held at the Netherlands Energy Research Foundation, ECN in Petten. Twenty three experts from the European Union, Japan, the Russian Federation and the United States exchanged results and analyses of completed experiments and discussed the program planning. The manufacturing of half-finished products and the optimization of subsequent heat treatments were presented and discussed in the first session. The problems and solutions to joining vanadium alloy half-finished products by welding and brazing have been addressed in another session. Corrosion and compatibility properties have been evaluated in a different session together with coating requirements. Several sessions were devoted to the effects of radiation on the mechanical properties, especially toughness, of vanadium alloys. Also the role of the transmutation product helium, in particular its introduction into specimens, was evaluated. The respective plans of the four parties for continuation of the ongoing research and development programs have been discussed with the emphasis on avoiding duplications in the area of radiation experiments. The critical issues were identified and the related priorities discussed in the time frame set by the schedule for the building of ITER test modules and with the long term DEMO requirements in mind. (orig.).

The extraction of vanadium (IV) from hydrochloric acid solutions by tricaprylmethylammonium chloride and trioctylamine

International Nuclear Information System (INIS)

Nakamura, Takato; Sato, Taichi

1980-01-01

The extraction of vanadium (IV) from hydrochloric acid solutions by tricaprylmethylammonium chloride (R 3 RNCl, Aliquat-336) and trioctylamine (R 3 N, TOA) in benzene has been investigated under various conditions. In addition, the extraction behaviour of vanadium into the organic phase has been examined by spectrophotometry and electron spin resonance (ESR) spectroscopy. From the distribution data, it is concluded that the extractions of vanadium (IV) from hydrochloric acid solutions by Aliquat-336 and TOA are expressed as VOCl 3 - (aq) + R 3 R'NCl(org) reversible R 3 R'NVOCl 3 (org) + Cl - (aq) and VOCl 2 (aq) + R 3 NHCl(org) reversible R 3 NHVOCl 3 (org) The electronic spectral and ESR results suggest that the complexes, R 3 R'NVOCl 3 and R 3 NH.VOCl 3 , formed in the organic phase are not always stable, but easily hydrolized or oxidized. (author)

Porphyrin doped vanadium pentoxide xerogel as electrode material

Energy Technology Data Exchange (ETDEWEB)

Anaissi, F.J.; Engelmann, F.M.; Araki, K.; Toma, H.E. [Sao Paulo Univ., SP (Brazil). Inst. de Quimica

2003-04-01

The lamellar composite material, VXG-TMPyP, obtained from the combination of cationic, water-soluble meso-(tetra-4-methyl-pyridinium)porphyrin (TMPyP) and vanadium pentoxide gel was investigated and employed as electrode modifying material. This material was isolated as a xerogel and characterized by X-ray diffraction, UV-Vis spectroscopy, cyclic voltammetry, spectro-electrochemistry and TG analysis. According to the X-ray diffraction data, the original VXG lamellar matrix framework is kept in the composite, evidencing a topotatic reaction. UV-Vis spectra indicated a strong interaction between VXG and TMPyP leading to the protonation of the porphyrin ring. In contrast with the vanadium oxide xerogel the new material is stable in water. The presence of the cationic porphyrin species in its structure turns it able to incorporate negatively charged ions, such as ferrocyanide and I{sup -}. The presence of the I{sub 2}/I{sup -} couple gives rise to a dramatic increase in the reversibility of the V{sup V/IV} process and in the charge capacity of the material. (authors)

Broad temperature adaptability of vanadium redox flow battery—Part 1: Electrolyte research

International Nuclear Information System (INIS)

Xiao, Shuibo; Yu, Lihong; Wu, Lantao; Liu, Le; Qiu, Xinping; Xi, Jingyu

2016-01-01

Highlights: • Impact of temperature (-35 °C-50 °C) on properties of VRFB electrolyte is studied. • V 2+ , V 3+ , V 3.5+ , V 4+ (VO 2+ ) and V 5+ (VO 2 + ) electrolytes are tested respectively. • V 2+ , V 3+ and V 3.5+ precipitates at low temperature can redissolve when temperature increases. • V 5+ precipitates at high temperature cannot redissolve when temperature decreases. • Conductivity and viscosity of the electrolytes are greatly affected by temperature. - Abstract: The broad temperature adaptability of vanadium redox flow battery (VRFB) is one of the key issues which affects the large-scale and safety application of VRFB. Typically, five types of vanadium electrolytes, namely V 2+ , V 3+ , V 3.5+ (V 3+ :VO 2+ = 1:1), V 4+ (VO 2+ ) and V 5+ (VO 2 + ), are the most common electrolytes' status existing in VRFB system. In this work, the physicochemical and electrochemical properties of these vanadium electrolytes are studied in detail at a broad temperature range (-35 °C–50 °C). The results show that all types of vanadium electrolytes are stable between -25 °C–30 °C. The temperature fluctuation will largely influence the conductivity and viscosity of the electrolytes. Besides, the electrochemical properties of the positive (VO 2+ ) and negative (V 3+ ) electrolytes are greatly affected by the temperature; and the charge transfer process fluctuates more greatly with the temperature variation than the charge diffusion process does. These results enable us to better and more comprehensively evaluate the performance of the electrolyte changing with the temperature, which will be beneficial for the rational choice of electrolyte for VRFB operation under various conditions.

Tight-binding study of the structural and magnetic properties of vanadium clusters

International Nuclear Information System (INIS)

Zhao Jijun; Lain, K.D.

1995-01-01

The structural and magnetic properties of small vanadium clusters are studied in the framework of tight-binding theory. According to parameters of the cluster dimer and bulk solid, we developed a tight-binding interatomic potential and calculated the bonding energies for the different possible structures to determine the ground state atomic configurations of the small vanadium clusters. The theoretical bonding energies for the vanadium clusters agree with the experiment much better than the simple droplet model. However, the calculated values for the clusters of odd atomic number are somewhat higher than the measured ones, corresponding to the pair occupation of delocalized 4s 1 electrons. Based on the optimized geometries, we study the magnetic properties of these clusters through a parametrized Hubbard Hamiltonian. We find the small V clusters of ground-state structures exhibit antiferromagnetic behavior while the alignment of local moments in the clusters with the unoptimized structures may show either ferromagnetic or antiferromagnetic characteristics. The average magnetic moments of the clusters decrease nonmonotonically as cluster size increases and the theoretical results are consistent with the upper limits obtained from a recent experiment. (orig.)

A novel magnesium-vanadium hydride synthesized by a gigapascal-high-pressure technique

Energy Technology Data Exchange (ETDEWEB)

Kyoi, Daisuke; Sato, Toyoto; Roennebro, Ewa; Tsuji, Yasufumi; Kitamura, Naoyuki; Ueda, Atsushi; Ito, Mikio; Katsuyama, Shigeru; Hara, Shigeta; Noreus, Dag; Sakai, Tetsuo

2004-07-28

A magnesium-based vanadium-doped hydride was prepared in a high-pressure anvil cell by reacting a MgH{sub 2}-25%V molar mixture at 8 GPa and 873 K. The new magnesium-vanadium hydride has a cubic F-centred substructure (a=4.721(1) Angst), with an additional superstructure, which could be described by a doubling of the cubic cell axis and a magnesium atom framework, including an ordered arrangement of both vanadium atoms and vacancies (a=9.437(3) Angst, space group Fm3-bar m (no. 225), Z=4, V=840.55 Angst{sup 3}). The metal atom structure is related to the Ca{sub 7}Ge type structure but the refined metal atom composition with vacancies on one of the magnesium sites corresponding to Mg{sub 6}V nearly in line with EDX analysis. The thermal properties of the new compound were also studied by TPD analysis and TG-DTA. The onset of the hydrogen desorption for the new Mg{sub 6}V hydride occurred at a 160 K lower temperature when compared to magnesium hydride at a heating rate of 10 K/min.

Preliminary environmental impact assessment for the final disposal of vanadium hazardous wastes

International Nuclear Information System (INIS)

Leyva Bombuse, D.; Peralta, J.L.; Gil Castillo, R.

2006-01-01

The aim of the present paper is the environmental impact assessment for the final management of vanadium wastes. The assessed practice is proposed as a final solution for a real problem in Cuba, related with the combustion fossil fuel burn in the electric generation. The study case, embrace the interim storage of hazardous wastes with high vanadium contents (5.08 T) and other heavy metals traces (Cr, Zn). According to the Cuban conditions (tacking into account the environmental regulations and infrastructure lack for the hazardous wastes disposal), it was decided the terrestrial dilution as a final disposal way. The environmental impact assessment methodology used, take into account, in the analyzed management practice, the actions, factors and environmental impacts. The positives and more relevant impacts were obtained for the socioeconomic means. The negative and irrelevant impacts were associated to the biotic and abiotic means. Socioeconomic factors were the most affected and the biotic and abiotic factors were less affected. The waste handling was the most relevant environmental action. According to the evaluated conditions, the obtained results showed that is feasible the terrestrial dilution as a sustainability way for the final disposal of vanadium hazardous wastes

Vanadium Effect on a Medium Carbon Forging Steel

Directory of Open Access Journals (Sweden)

Carlos Garcia-Mateo

2016-05-01

Full Text Available In the present work the influence of vanadium on the hardenability and the bainitic transformation of a medium carbon steel is analyzed. While V in solid solution enhances the former, it hardly affects bainitic transformation. The results also reveal an unexpected result, an increase of the prior austenite grain size as the V content increases.

Halofunctionalization of alkenes by vanadium chloroperoxidase from Curvularia inaequalis

NARCIS (Netherlands)

Dong, J.; Fernandez Fueyo, E.; Li, Jingbo; Guo, Zheng; Renirie, Rokus; Wever, Ron; Hollmann, F.

The vanadium-dependent chloroperoxidase from Curvularia inaequalis is a stable and efficient biocatalyst for the hydroxyhalogenation of a broad range of alkenes into halohydrins. Up to 1 200 000 TON with 69 s−1 TOF were observed for the biocatalyst. A bienzymatic cascade to yield epoxides as

Development of electrically insulating self-healing coatings in vanadium alloys for lithium fusion reactor

International Nuclear Information System (INIS)

1999-01-01

Problems on electrically insulating self-healing coatings (SHC) on vanadium alloys for lithium fusion reactor systems are considered. In particular, the SHC stability and radiation resistance in lithium and effect of magnetic field on the efficiency of the TNR lithium systems are studied. New technological methods for application of self-healing coatings and study on their properties are developed. The vanadium-lithium materials testing in pile loops for solution of the above problems under conditions of the lithium TNR is described [ru

Hugoniot measurements in vanadium using the LNL two-stage light-gas gun

International Nuclear Information System (INIS)

Gathers, G.R.; Mitchell, A.C.; Holmes, N.C.

1983-01-01

Hugoniot measurements on vanadium have been made using the LLNL two-stage light-gas gun. The direct collision method with electrical pins and a tantalum flyer accelerated to 6.28 km/s was used. Alt'shuler, et. al., have reported Hugoniot measurements in vanadium using explosives and the impedance match method. They reported a kink in the U/sub s/ - U/sub p/ relationship at 183 GPa, and attribute it to electronic transitions. The upper portion of their curve is based on a single point at 339 GPa. The present work was performed to further investigate the equation-of-state in the high-pressure range

Partial molar volumes of hydrogen and deuterium in niobium, vanadium, and tantalum

International Nuclear Information System (INIS)

Peterson, D.T.; Herro, H.M.

1983-01-01

The partial molar volumes of hydrogen and deuterium were measured in vanadium, niobium, and tantalum by a differential pressure technique. One-half of an electrolytically charged sample plat was compressed between hardened steel blocks in a hydraulic press. The activity of hydrogen in the hig pressure region was raised and caused hydrogen to diffuse into the low pressure region. The partia molar volume was calculated from the ratio of the hydrogen concentrations in the high and low pressure regions of the sample. Small isotope effects were found in the partial molar volume. Hydrogen had the larger volume in niobium and tantalum, but the reverse was true in vanadium

Determination of absolute oscillator strengths for doubly-ionized vanadium

International Nuclear Information System (INIS)

Goly, A.

1978-01-01

Oscillator strengths of thirty V III lines in the wavelength region from 2300A to 2600A were determined by the emission method using a modified wallstabilized cascade are operating at atmospheric pressure in helium with traces of VOCl 3 -vapour. The plasma radiation was analyzed by using a high dispersion grating spectrograph (0.7 A/mm) and Kodak IIaO-plates. Conventional techniques of intensity measurement were employed. Under the physical conditions created the helium plasma was found more or less distant from LTE, but for singly- and doubly-ionized vanadium according to Drawin's criteria, a Boltzmann distribution of level population can be assumed (and has been proved for VII). Measuring a set of intensities of V II lines (with different energies of upper levels) and using gf-values, obtained previously in an argon-vanadium plasma in LTE, excitation temperatures were determined from slopes of Boltzmann plots. (orig.) 891 WL [de

Effect of vanadium and yttrium doping on BSCCO superconductors

International Nuclear Information System (INIS)

Mohamed, S.B.; Halim, S.A.; Azhan, H.; Sidek, H.A.A; Tee, T.W.; Hassan, Z.A.

1999-01-01

The effect of vanadium and yttrium doping on the superconductivity is investigated. The doping was done on the calcium site ranging from x=0.00-0.10. The temperature dependence of electrical resistance and AC susceptibility measurements were made on these samples. The zero resistance for vanadium doped samples varied from 107 K (x = 0.00) to 68.5K (x = 0.10), whereas for yttrium doped samples it varied from 107 K (x = 0.00) to 54K (x 0.10). The volume fraction of the 2223 phase for both dopalit decreases witli increasing doping concentration. The nature of the temperature derivative of the resistance curves indicates the presence of a superconducting transition between grains coupled by weak links. The AC susceptibility data show enrichment of the volume fraction of the low Tc phase at higher compositions. The presence of low Tc phase (∼70 K) is visible in the susceptibility data. X-ray diffraction confirms the presence of mixed phases in the samples. (author)

The fabrication of a vanadium-stainless steel test section for MHD testing of insulator coatings in flowing lithium

International Nuclear Information System (INIS)

Reed, C.B.; Mattas, R.F.; Smith, D.L.; Chung, H.; Tsai, H.-C.; Morgan, G.D.; Wille, G.W.; Young, C.

1996-01-01

To test the magnetohydrodynamic (MHD) pressure drop reduction performance of candidate insulator coatings for the ITER Vanadium/Lithium Breeding Blanket, a test section comprised of a V- 4Cr-4Ti liner inside a stainless steel pipe was designed and fabricated. Theoretically, the MHD pressure drop reduction benefit resulting, from an electrically insulating coating on a vanadium- lined pipe is identical to the benefit derived from an insulated pipe fabricated of vanadium alone. A duplex test section design consisting of a V alloy liner encased in a SS pressure boundary provided protection for vanadium from atmospheric contamination during operation at high temperature and obviated any potential problems with vanadium welding while also minimizing the amount of V alloy material required. From the MHD and insulator coating- point of view, the test section outer SS wall and inner V alloy liner can be modeled simply as a wall having a sandwich construction. Two 52.3 mm OD x 2.9 m long V-alloy tubes were fabricated by Century Tubes from 64 mm x 200 mm x 1245 mm extrusions produced by Teledyne Wah Chang. The test section's duplex structure was subsequently fabricated at Century Tubes by drawing down a SS pipe (2 inch schedule 10) over one of the 53.2 mm diameter V tubes

Synthesis and infrared spectra of Vanadium (III) prussian blue complexes

International Nuclear Information System (INIS)

Toma, H.E.; Lellis, F.T.P.

1987-01-01

The synthesis and characterization of a series of polymeric pigments containing vanadium (III) and hexacryano or substituted pentacyanoferrate (II) complexes are studied. The role of the intervalence transfer interactions in the complexes is discussed. (M.J.C.) [pt

Effect of vanadium on the obtaining of the titanium dioxide by Sol-Gel Method

International Nuclear Information System (INIS)

Granado, S.R.; Silva, D.W.; Lopes, S.A.; Cavalheiro, A.A.

2011-01-01

The obtaining of transition metal modified titanium dioxide (TiO 2 ) can be a promising path to promote changes in crystal structure of anatase phase in order to displace the band gap toward frequencies near to visible region. The insertion of the heterovalent ions such as vanadium can be shift the titanium coordination number in the anatase matrix, leading to important changes in the photonic characteristics of the material. In Sol-Gel method, the presence of the non alkoxide precursors can affects the stability of the solution and the gelifying process, with consequences on the characteristics of the material. In this work, it was investigated the effect of 5mol% of vanadium by thermal analysis of the dried gel and XRD and adsorption isotherm in the samples obtained at different temperatures. The decomposition steps of the precursor were associated to phase formation in the material, leading to conclusion that the presence of vanadium affects the stability of anatase phase. (author)

A three-dimensional model for negative half cell of the vanadium redox flow battery

International Nuclear Information System (INIS)

Ma Xiangkun; Zhang Huamin; Xing Feng

2011-01-01

A stationary, isothermal, three-dimensional model for negative half cell of the vanadium redox flow battery is developed, which is based on the comprehensive conservation laws, such as charge, mass and momentum, together with a kinetic model for reaction involving vanadium species. The model is validated against the results calculated by the available two-dimensional model. With the given geometry of the negative half cell, the distributions of velocity, concentration, overpotential and transfer current density in the sections that are perpendicular and parallel to the applied current are studied. It is shown that the distribution of the electrolyte velocity in the electrode has significant impact on the distribution of concentration, overpotential and transfer current density. The lower velocity in the electrode will cause the higher overpotential, further result in the side reaction and corrosion of key materials locally. The development of the design of the vanadium redox flow battery is discussed, and the further research is proposed.

Effect of helium on the tensile properties of several vanadium alloys

International Nuclear Information System (INIS)

Braski, D.N.

1985-01-01

Specimens of three vanadium alloys were implanted with different levels of 3 He using the tritium trick and subsequently tensile tested at elevated temperatures. The V-15Cr-5Ti and V-3Ti-1Si specimens were embrittled by 3 He at a level of 150 at. ppm while the VANSTAR-7 specimens were not. The embrittlement appeared to be caused by extensive 3 He bubble networks and possibly precipitate particles on the grain boundaries; hopefully the bubble distribution can be changed (for better simulation) by altering parameters of the tritium trick. The results of the investigation also show that the embrittlement resistance of vanadium alloys can be improved by adjustment of their composition and/or microstructure. 1 reference, 4 figures, 1 table

Characteristics of Vanadium Doped And Bamboo Activated Carbon Coated LiFePO4 And Its Performance For Lithium Ion Battery Cathode

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Nofrijon Sofyan

2018-04-01

Full Text Available Vanadium doped and bamboo activated carbon coated lithium iron phosphate (LiFePO4 used for lithium ion battery cathode has been successfully prepared. Lithium iron phosphate was prepared through a wet chemical method followed by a hydrothermal process from the starting materials of LiOH, NH4H2PO4, and FeSO4.7H2O. The dopant variations of 0 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% of vanadium and a fixed 3 wt.% of bamboo activated carbon were carried out via a solid-state reaction process each by using NH4VO3 as a source of vanadium and carbon pyrolyzed from bamboo tree, respectively. The characterization was carried out using X-ray Diffraction (XRD for the phase formed and its crystal structure, Scanning Electron Microscope (SEM for the surface morphology, Electrochemical Impedance Spectroscopy (EIS for the conductivity, and battery analyzer for the performance of lithium ion battery cathode. The XRD results show that the phase formed has an olivine based structure with an orthorhombic space group. Morphology examination revealed that the particle agglomeration decreased with the increasing level of vanadium concentrations. Conductivity test showed that the impedance of solid electrolyte interface decreased with the increase of vanadium concentration indicated by increasing conductivity of 1.25 x 10-5 S/cm, 2.02 x 10-5 S/cm, 4.37 x 10-5 S/cm, and 5.69 x 10-5 S/cm, each for 0 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% vanadium, respectively. Vanadium doping and bamboo activated carbon coating are promising candidate for improving lithium ion battery cathode as the initial charge and discharge capacity at 0.5C for LiFePO4/C at 7 wt.% vanadium is in the range of 8.0 mAh/g.

The thermodynamic characteristics of the reaction between vanadium(5) and hydrogen peroxide in concentrated solutions of perchloric acid

International Nuclear Information System (INIS)

Vorob'ev, P.N.; Dmitrieva, N.G.; Poteshonkova, T.A.

2001-01-01

Stability constants of vanadium(5) complex with hydrogen peroxide and enthalpy of vanadium(5) complexing with hydrogen peroxide are determined at acidity of solution c(H + ) = 5.00 mol/l, temperature T = 298.15 K and values of ionic force: I = 5, 6 and 7. Standard thermodynamic characteristics of vanadium(5) peroxide complex formation were calculated. At zeroth ionic force the value of complexing enthalpy Δ r H 298.15 deg is equal to -48.59 ± 0.33 kJ/mol, standard enthalpy of peroxide vanadium(5) complex formation Δ f H 298.15 deg is equal to -895.49 ± 1.51 kJ/mol; Δ r G 298.15 deg = -36.51 kJ/mol, Δ r S 298.15 deg -40.51 J/(mol K). As it is shown by calculations, standard change in entropy of the reaction has a minus sign, that is unique to complexation with neutral ligand [ru

Friedel-Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery.

Science.gov (United States)

Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

2013-12-30

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel-Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion.

Extraction of bivalent vanadium as its pyridine thiocyanate complex and separation from uranium, titanium, chromium and aluminium

International Nuclear Information System (INIS)

Yatirajam, V.; Arya, S.P.

1975-01-01

A simple method is described for the extraction of V(II) as its pyridine thiocyanate complex. Vanadate is reduced to V(II) in 1 to 2 N sulphuric acid by zinc amalgam. Thiocyanate and pyridine are added, the solution is adjusted to pH 5.2 to 5.5 and the complex extracted with chloroform. The vanadium is back-extracted with peroxide solution. Zinc from the reductant accompanies the vanadium but alkali and alkaline earth metal ions, titanium, uranium, chromium and aluminium are separated, besides those ions reduced to the elements by zinc amalgam. The method takes about 20 min and is applicable to microgram as well as milligram amounts of vanadium. (author)

The influence of deposition temperature on vanadium dioxide thin films microstructure and physical properties

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Velaphi Msomi

2010-10-01

Full Text Available Vanadium dioxide thin films were successfully prepared on soda lime glass substrates using the optimised conditions for r.f-inverted cylindrical magnetron sputtering. The optimised deposition parameters were fixed and then a systematic study of the effect of deposition temperature, ranging from 450 °C to 550 °C, on the microstructure of thermochromic thin films was carried out. The deposited films were found to be well crystallised, showing strong texture corresponding to the (011 plane, indicating the presence of vanadium dioxide.

A lattice location study of oxygen in vanadium by 1-MeV deuteron channeling

International Nuclear Information System (INIS)

Takahashi, Junzo; Koiwa, Masahiro; Hirabayashi, Makoto; Yamaguchi, Sadae; Fujino, Yutaka.

1978-01-01

A direct determination of the lattice location of oxygen in vanadium single crystals has been made by means of ion channeling and the ion-induced nuclear reaction, 16 O(d, p) 17 O*. Channeling angular distribution measurements along principal axial and planar directions indicate that oxygen atoms occupy the octahedral interstices in vanadium. The shapes of the flux peaks observed for the [100], [110] and [111] directions have been compared with those of the theoretical curves calculated on the multiple strings model assuming statistical equilibrium. (author)

Combined effect of vanadium and nickel on lipid peroxidation and ...

African Journals Online (AJOL)

use

2011-12-12

Dec 12, 2011 ... to nickel led to a significant decrease (p < 0.001) in SOD, GST activities in liver and GSH content in ..... administration and GSH is oxidized to disulfide form .... Chasteen N (1983). The biochemistry of vanadium. Struct. Bond.

Synthesis, crystal structure, and spectroscopic characterization of two new binuclear complexes of manganese(II) and vanadium(V) with dipicolinate ligands containing 2-aminopyrimidinium as a counter cation

Czech Academy of Sciences Publication Activity Database

Tabatabaee, M.; Mahmoodikhah, H.; Ahadiat, G.; Dušek, Michal; Pojarová, Michaela

2013-01-01

Roč. 144, č. 5 (2013), s. 621-626 ISSN 0026-9247 R&D Projects: GA ČR(CZ) GAP204/11/0809 Institutional support: RVO:68378271 Keywords : manganese complex * vanadium complex * dipicolinic ligand * crystal structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.347, year: 2013

Fast Neutron Elastic and Inelastic Scattering of Vanadium

Energy Technology Data Exchange (ETDEWEB)

Holmqvist, B; Johansson, S G; Lodin, G; Wiedling, T

1969-11-15

Fast neutron scattering interactions with vanadium were studied using time-of-flight techniques at several energies in the interval 1.5 to 8.1 MeV. The experimental differential elastic scattering cross sections have been fitted to optical model calculations and the inelastic scattering cross sections have been compared with Hauser-Feshbach calculations, corrected for the fluctuation of compound-nuclear level widths.

Controlled synthesis and electrochemical properties of vanadium oxides with different nanostructures

International Nuclear Information System (INIS)

Zhang, Yifu; Zhou, Min; Huang, Chi; Chen, Chongxue; Cao, Yuliang; Fan, Meijuan; Li, Houbin; Liu, Xinghai; Xie, Guangyong

2012-01-01

Vanadium oxides (V 3 O 7 .H 2 O and VO 2 ) with different morphologies have been selectively synthesized by a facile hydrothermal approach using glucose as the reducing and structure-directing reagent. The as-obtained V 3 O 7 .H 2 O nanobelts have a length up to several tens of micrometers, width of about 60-150 nm and thickness of about 5-10 nm, while the as-prepared VO 2 (B) nanobelts have a length of about 1.0- 7 μm, width, 80-140 nm and thickness, 2-8 nm. It was found that the quantity of glucose, the reaction temperature and the reaction time had significant influence on the compositions and morphologies of final products. Vanadium oxides with different morphologies were easily synthesized by controlling the concentration of glucose. The formation mechanism was also briefly discussed, indicating that glucose played different roles in synthesizing various vanadium oxides. The phase transition from VO 2 (B) to VO 2 (M) were investigated and the phase transition temperature of the VO 2 (M) appeared at around 68 deg C. Furthermore, the electrochemical properties of V 3 O 7 .H 2 O nanobelts, VO 2 (B) nanobelts and VO 2 (B) nanosheets were investigated and they exhibited a high initial discharge capacity of 296, 247 and 227 mAh/g, respectively. (author)

Impurity content of reduced-activation ferritic steels and a vanadium alloy

International Nuclear Information System (INIS)

Klueh, R.L.; Grossbeck, M.L.; Bloom, E.E.

1997-01-01

Inductively coupled plasma mass spectrometry was used to analyze a reduced-activation ferritic/martensitic steel and a vanadium alloy for low-level impurities that would compromise the reduced-activation characteristics of these materials. The ferritic steel was from the 5-ton IEA heat of modified F82H, and the vanadium alloy was from a 500-kg heat of V-4Cr-4Ti. To compare techniques for analysis of low concentrations of impurities, the vanadium alloy was also examined by glow discharge mass spectrometry. Two other reduced-activation steels and two commercial ferritic steels were also analyzed to determine the difference in the level of the detrimental impurities in the IEA heat and steels for which no extra effort was made to restrict some of the tramp impurities. Silver, cobalt, molybdenum, and niobium proved to be the tramp impurities of most importance. The levels observed in these two materials produced with present technology exceeded the limits for low activation for either shallow land burial or recycling. The chemical analyses provide a benchmark for the improvement in production technology required to achieve reduced activation; they also provide a set of concentrations for calculating decay characteristics for reduced-activation materials. The results indicate the progress that has been made and give an indication of what must still be done before the reduced-activation criteria can be achieved

Effects of Vanadium Pentoxide on the Histological and Sperm ...

African Journals Online (AJOL)

The pharmacological effects of intraperitoneal administration of different doses of vanadium pentoxide (V2O5) on the histological and sperm parameters of male guinea pigs were investigated. Also investigated were the effects of oral pretreatment with different doses of vitamin E (a known protein kinase C inhibitor) on the ...

Determination of mercury and vanadium concentration in Johnius belangerii (C) fish in Musa estuary in Persian Gulf

International Nuclear Information System (INIS)

Fard, Neamat Jaafarzadeh Haghighi; Ravanbakhsh, Maryam; Ramezani, Zahra; Ahmadi, Mehdi; Angali, Kambiz Ahmadi; Javid, Ahmad Zare

2015-01-01

Highlights: • Hg & V in Johnius belangerii fish in Musa estuary, Persian Gulf was determined. • Significant reverse relationship was between concentrations of Hg & V. • Weight and length had significant direct relationship with Hg concentration. • Length had significant reverse relationship with V concentration. • Concentrations of Hg & V were higher than threshold limits. - Abstract: The main aim of this study was to determine the concentrations of mercury and vanadium in Johnius belangerii (C) fish in the Musa estuary. A total of 67 fishes were caught from the Musa estuary during five intervals of 15 days in the summer of 2013. After biometric measurements were conducted, the concentrations of mercury and vanadium were measured in the muscle tissue of fish using a direct method analyzer (DMA) and a graphite furnace atomic absorption spectrophotometer, respectively. The mean concentration of mercury and vanadium in the muscle tissue of fish was 3.154 ± 1.981 and 2.921 ± 0.873 mg/kg w.w, respectively. The generalized linear model (GLM) analysis showed a significantly positive relationship among mercury concentration, length, and weight (P = 0.000). In addition, there was a significantly negative relationship between vanadium concentration and fish length (P = 0.000). A reverse association was found between concentrations of mercury and vanadium. Mercury concentration exceeded the allowable standards of the Environmental Protection Agency (EPA), the World Health Organization (WHO), and the Food and Drug Administration (FDA) in J. belangerii (C)

Structural, optical and electrochemical properties of F-doped vanadium oxide transparent semiconducting thin films

Energy Technology Data Exchange (ETDEWEB)

Mousavi, M.; Khorrami, G.H. [University of Bojnord, Department of Physics, Faculty of Basic Science, Bojnord (Iran, Islamic Republic of); Kompany, A. [Ferdowsi University of Mashhad, Department of Physics, Mashhad (Iran, Islamic Republic of); Yazdi, S.T. [Payame Noor University (PNU), Department of Physics, Tehran (Iran, Islamic Republic of)

2017-12-15

In this study, F-doped vanadium oxide thin films with doping levels up to 60 at % were prepared by spray pyrolysis method on glass substrates. To measure the electrochemical properties, some films were deposited on fluorine-tin oxide coated glass substrates. The effect of F-doping on the structural, electrical, optical and electrochemical properties of vanadium oxide samples was investigated. The X-ray diffractographs analysis has shown that all the samples grow in tetragonal β-V{sub 2}O{sub 5} phase structure with the preferred orientation of [200]. The intensity of (200) peak belonging to β-V{sub 2}O{sub 5} phase was strongest in the undoped vanadium oxide film. The scanning electron microscopy images show that the samples have nanorod- and nanobelt-shaped structure. The size of the nanobelts in the F-doped vanadium oxide films is smaller than that in the pure sample and the width of the nanobelts increases from 30 to 70 nm with F concentration. With increasing F-doping level from 10 to 60 at %, the resistivity, the transparency and the optical band gap decrease from 111 to 20 Ω cm, 70 to 50% and 2.4 to 2.36 eV, respectively. The cyclic voltammogram (CV) results show that the undoped sample has the most extensive CV and by increasing F-doping level from 20 to 60 at %, the area of the CV is expanded. The anodic and cathodic peaks in F-doped samples are stronger. (orig.)

Kinetic and Mechanism Study of Vanadium Acid Leaching from Black Shale Using Microwave Heating Method

Science.gov (United States)

Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

2018-04-01

The leaching kinetics of the vanadium leaching process were investigated by the comparison of microwave heating and conventional heating methods. Microwave heating with CaF2 had a synergistic effect and improved the vanadium leaching efficiency. In contrast to conventional heating leaching, microwave heating accelerated the vanadium leaching rate by approximately 1-3% and by approximately 15% when CaF2 was also used. The kinetics analysis showed that the calculated activation energy decreased in the microwave heating method in the presence and absence of CaF2. The control procedure of leaching also changed from a chemical reaction control step to a mixed chemical diffusion control step upon the addition of CaF2. Microwave heating was shown to be suitable for leaching systems with diffusion or mixed chemical diffusion control steps when the target mineral does not have a microwave absorbing ability.

A vanadium alloy for the application in a liquid metal blanket of a fusion reactor

Science.gov (United States)

Borgstedt, H. U.; Grundmann, M.; Konys, J.; Perić, Z.

1988-07-01

The vanadium alloy V3Ti1Si has been corrosion tested in liquid lithium and the eutectic alloy Pb-17Li at 550°C. This alloy has a comparable corrosion resistance to the alloy V15Cr5Ti in lithium. In this molten metal it is superior to stainless steel AISI 316. In the Pb-17Li melt it is even superior to martensitic steels. The alloy has only a weak tendency to be dissolved. It is sensitive to an exchange of non-metallic elements, which causes the formation of a hardened surface layer. These chemical effects are influenced by the mass and surface ratios of the vanadium alloy to the molten metals and other structural materials. These ratios are unfavorable in the two test loops. The effects might be less pronounced in a vanadium alloy/liquid metal fusion reactor blanket.

Recovery of vanadium (V) from used catalysts in sulfuric acid production units by oxalic acid

International Nuclear Information System (INIS)

Abdulbaki, M.; Shino, O.

2009-07-01

Vanadium penta oxide (V 2 O 5 ), is used, in large quantities as a catalyst for the oxidation of SO 2 to SO 3 in sulfuric acid production units, during the oxidation process the level of the oxidation declines with the time because of catalyst poisoning. So the spent catalyst is usually through out in a specified special places by General Fertilizer Company which causes a pollution of the land. The present paper, studies the recovery of vanadium from the spent catalyst by using the oxalic acid. The optimal conditions of spent catalyst leaching have been studied. It has been shown that 2%(w/w) of oxalic acid is the most suitable for leaching process at 70 degree centigrade. The precipitation of vanadium using some alkaline media NH 4 OH has been also studied, it has been shown that ammonium hydroxide was the best at 50 degree centigrade. (author)

Kinetic and Mechanism Study of Vanadium Acid Leaching from Black Shale Using Microwave Heating Method

Science.gov (United States)

Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

2018-06-01

The leaching kinetics of the vanadium leaching process were investigated by the comparison of microwave heating and conventional heating methods. Microwave heating with CaF2 had a synergistic effect and improved the vanadium leaching efficiency. In contrast to conventional heating leaching, microwave heating accelerated the vanadium leaching rate by approximately 1-3% and by approximately 15% when CaF2 was also used. The kinetics analysis showed that the calculated activation energy decreased in the microwave heating method in the presence and absence of CaF2. The control procedure of leaching also changed from a chemical reaction control step to a mixed chemical diffusion control step upon the addition of CaF2. Microwave heating was shown to be suitable for leaching systems with diffusion or mixed chemical diffusion control steps when the target mineral does not have a microwave absorbing ability.

Electron paramagnetic resonance studies on conformation states and metal ion exchange properties of vanadium bromoperoxidase

International Nuclear Information System (INIS)

de Boer, E.; Boon, K.; Wever, R.

1988-01-01

An electron paramagnetic resonance (EPR) study was carried out to examine structural aspects of vanadium-containing bromoperoxidase from the brown seaweed Ascophyllum nodosum. At high pH, the reduced form of bromoperoxidase showed an apparently axially symmetric EPR signal with 16 hyperfine lines. When the pH was lowered, a new EPR spectrum was formed. When EPR spectra of the reduced enzyme were recorded in the pH range from 4.2 to 8.4, it appeared that these changes were linked to a functional group with an apparent pK/sub a/ of about 5.4. In D 2 O this value for the pK/sub a/ was 5.3. It is suggested that these effects arise from protonation of histidine or aspartate/glutamate residues near the metal ion. The values for the isotropic hyperfine coupling constant of the reduced enzyme at both high and low pH are also consistent with a ligand field containing nitrogen and/or oxygen donor atoms. When reduced bromoperoxidase was dissolved in D 2 O or H 2 17 O instead of H 2 16 O, vanadium (IV) hyperfine line widths were markedly affected, demonstrating that water is a ligand of the metal ion. Together with previous work these findings suggest that vanadium (IV) is not involved in catalytic turnover and confirm the model in which the vanadium (V) ion of the native enzyme only serves to bind both hydrogen peroxide and bromide. After excess vanadate was added to a homogeneous preparation of purified bromoperoxidase, the extent of vanadium bound to the protein increased from 0.5 to 1.1, with a concomitant enhancement of enzymic activity. Finally, it is demonstrated that both vanadate (VO 4 3- ) and molybdate (MoO 4 2- ) compete for the same site on apobromoperoxidase

Solution casting Nafion/polytetrafluoroethylene membrane for vanadium redox flow battery application

International Nuclear Information System (INIS)

Teng, Xiangguo; Sun, Cui; Dai, Jicui; Liu, Haiping; Su, Jing; Li, Faqiang

2013-01-01

Highlights: ► Nafion/polytetrafluoroethylene (PTFE) blend membranes were prepared by solution casting method. ► The blend membranes were tested for vanadium redox flow battery (VRB) application. ► The blend membranes show lower vanadium ion permeability than that of recast Nafion membrane. ► In VRB single cell test, the blend membrane shows superior performances than that of pure recast Nafion. -- Abstract: Solution casting method was adopted using Nafion and polytetrafluoroethylene (PTFE) solution to prepare Nafion/PTFE blend membranes for vanadium redox flow battery application. The physicochemical properties of the membranes were characterized by using water uptake, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal analysis (TA). The electrochemical properties of the membranes were examined by using electrochemical impedance spectroscopy (EIS) and single cell test. Despite the high miscibility of PTFE with Nafion, the addition of hydrophobic PTFE reduces the water uptake, ion exchange capacity (IEC) and conductivity of blend membranes. But PTFE can increase the crystallinity, thermal stability of Nafion/PTFE membranes and reduce the vanadium permeability. The blend membrane with PTFE (30 wt%, N 0.7 P 0.3 ) was chosen and investigated for VRB single cell test. The energy efficiency of this VRB with N 0.7 P 0.3 membrane was 85.1% at current density of 50 mA cm −2 , which was superior to that of recast Nafion (r-Nafion) membrane (80.5%). Self-discharge test shows that the decay of open circuit potential of N 0.7 P 0.3 membrane is much lower than that of r-Nafion membrane. More than 50 cycles charge–discharge test proved that the N 0.7 P 0.3 membrane possesses high stability in long time running. Chemical stabilities of the chosen N 0.7 P 0.3 membrane are further proved by soaking the membrane for 3 weeks in highly oxidative V(V) solution. All results suggest that the addition of PTFE is a simple and effective way to

A study of defect cluster formation in vanadium by heavy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Sekimura, Naoto; Shirao, Yasuyuki; Morishita, Kazunori [Tokyo Univ. (Japan)

1996-10-01

Formation of defect clusters in thin foils of vanadium was investigated by heavy ion irradiation. In the very thin region of the specimens less than 20 nm, vacancy clusters were formed under gold ion irradiation, while very few clusters were detected in the specimens irradiated with 200 and 400 keV self-ions up to 1 x 10{sup 16} ions/m{sup 2}. The density of vacancy clusters were found to be strongly dependent on ion energy. Only above the critical value of kinetic energy transfer density in vanadium, vacancy clusters are considered to be formed in the cascade damage from which interstitials can escape to the specimen surface in the very thin region. (author)

Thermal desorption of toluene from Vanadium-containing catalysts coated onto various carriers

Directory of Open Access Journals (Sweden)

Z. Zheksenbaeva

2012-12-01

Full Text Available The method temperature-programmed desorption has been studied the state of toluene on the surface-modified vanadium catalysts on different carriers. Among the investigated carriers the most active in the reaction of partial oxidation of toluene is anatase structural titanium dioxide. For the partial oxidation of toluene on modified vanadium-containing catalysts deposited on TiO2 was tested. It was found that on the catalyst 20%V2O5-5%MoO3-2%Sb2O3/TiO2 at a temperature of 673K, volume rate of 15 thousand hours-1 oxidation of toluene is 80% c yield of benzoic acid with a selectivity of  70% of 87.5%.

Influence of hydrogen on high cycle fatigue of polycrystalline vanadium

International Nuclear Information System (INIS)

Chung, D.W.; Lee, K.S.; Stoloff, N.S.

1977-02-01

The room temperature fatigue behavior of several polycrystalline V-H 2 alloys is described. Hydrogen extends the life of unnotched vanadium but has a deleterious effect in notched materials. Crack propagation data are correlated with tensile yield stress and cyclic strain hardening data

Roll-to-Roll Processing of Inverted Polymer Solar Cells using Hydrated Vanadium(VOxide as a PEDOT:PSS Replacement

Directory of Open Access Journals (Sweden)

Frederik C. Krebs

2011-01-01

Full Text Available The use of hydrated vanadium(Voxide as a replacement of the commonly employed hole transporting material PEDOT:PSS was explored in this work. Polymer solar cells were prepared by spin coating on glass. Polymer solar cells and modules comprising 16 serially connected cells were prepared using full roll-to-roll (R2R processing of all layers. The devices were prepared on flexible polyethyleneterphthalate (PET and had the structure PET/ITO/ZnO/P3HT:PCBM/V2O5·(H2On/Ag. The ITO and silver electrodes were processed and patterned by use of screen printing. The zinc oxide, P3HT:PCBM and vanadium(Voxide layers were processed by slot-die coating. The hydrated vanadium(Voxide layer was slot-die coated using an isopropanol solution of vanadyl-triisopropoxide (VTIP. Coating experiments were carried out to establish the critical thickness of the hydrated vanadium(Voxide layer by varying the concentration of the VTIP precursor over two orders of magnitude. Hydrated vanadium(Voxide layers were characterized by profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and grazing incidence wide angle X-ray scattering. The power conversion efficiency (PCE for completed modules was up to 0.18%, in contrast to single cells where efficiencies of 0.4% were achieved. Stability tests under indoor and outdoor conditions were accomplished over three weeks on a solar tracker.

Hysteresis phenomena at metal-semiconductor phase transformation in vanadium oxides

International Nuclear Information System (INIS)

Lanskaya, T.G.; Merkulov, I.A.; Chudnovski , F.A.

1978-01-01

The hysteresis phenomena during the metal-semiconductor phase transformation (MSPT) in vanadium oxides are investigated. It is shown experimentally that the hysteresis effects during MSPT in vanadium oxides are associated not only with the martensite nature of the transformation, but also with activation processes. It is shown that the hysteresis phenomena during MSPT may be described by the distribution function of microregions of the crystal in the phase transformation temperature T 0 and the coercive temperature Tsub(c). An experimental method for constructing this distribution function was worked out. An analysis of the experimental data shows that finely dispersed films are characterized by a wide range of values of T 0 and Tsub(c) (55 deg C 0 <65 deg C, 6 deg C< Tsub(c)<12 deg C). The peculiarities of the optical recording of information on monocrystal and finely dispersed films are considered

Phase equilibria in the niobium-vanadium-hydrogen system

Energy Technology Data Exchange (ETDEWEB)

Bethin, J. (Grumman Aerospace Corp., Bethpage, NY (USA)); Welch, D.O. (Brookhaven National Lab., Upton, NY (USA)); Pick, M.A. (Commission of the European Communities, Abingdon (UK). JET Joint Undertaking)

1990-01-01

The effect of vanadium additions to niobium on the metal-hydrogen phase equilibria has been studied. Measurements of the equilibrium H{sub 2}(D{sub 2}) pressure-composition-temperature isotherms for Nb{sub 1-x}V{sub x} alloys with 0{le}x<0.2 were used to determine the depression of the {alpha} - {alpha}' critical temperature with increasing vanadium concentration. A simple lattice-fluid model guided reduction of the data. Changes in the triple point temperature as well as the shift of the {zeta} {yields} {epsilon} phase transition were determined by differential scanning calorimetry measurements. A rapid overall depression was found, of the order of 7 K (at.% substituted V){sup -1}, for the metal-hydrogen (deuterium) phase boundary structure when compared with the Nb-H system in the hydrogen concentration range of interest. The results explain the enhanced terminal solubility of hydrogen in this system found previously by other authors. The changes in the phase equilibria are discussed in terms of the effect of hydrogen trapping and compared with the results of a cluster-variation calculation for random-field systems of previous authors, taking into account a distribution of H-site energies due to alloying. (author).

Vanadium(III)-l-cysteine enhances the sensitivity of murine breast adenocarcinoma cells to cyclophosphamide by promoting apoptosis and blocking angiogenesis.

Science.gov (United States)

Basu, Abhishek; Bhattacharjee, Arin; Baral, Rathindranath; Biswas, Jaydip; Samanta, Amalesh; Bhattacharya, Sudin

2017-05-01

Various epidemiological and preclinical studies have already established the cancer chemopreventive potential of vanadium-based compounds. In addition to its preventive efficacy, studies have also indicated the abilities of vanadium-based compounds to induce cell death selectively toward malignant cells. Therefore, the objective of the present investigation is to improve the therapeutic efficacy and toxicity profile of an alkylating agent, cyclophosphamide, by the concurrent use of an organovanadium complex, vanadium(III)-l-cysteine. In this study, vanadium(III)-l-cysteine (1 mg/kg body weight, per os) was administered alone as well as in combination with cyclophosphamide (25 mg/kg body weight, intraperitoneal) in concomitant and pretreatment schedule in mice bearing breast adenocarcinoma cells. The results showed that the combination treatment significantly decreased the tumor burden and enhanced survivability of tumor-bearing mice through generation of reactive oxygen species in tumor cells. These ultimately led to DNA damage, depolarization of mitochondrial membrane potential, and apoptosis in tumor cells. Further insight into the molecular pathway disclosed that the combination treatment caused upregulation of p53 and Bax and suppression of Bcl-2 followed by the activation of caspase cascade and poly (ADP-ribose) polymerase cleavage. Administration of vanadium(III)-l-cysteine also resulted in significant attenuation of peritoneal vasculature and sprouting of the blood vessels by decreasing the levels of vascular endothelial growth factor A and matrix metalloproteinase 9 in the ascites fluid of tumor-bearing mice. Furthermore, vanadium(III)-l-cysteine significantly attenuated cyclophosphamide-induced hematopoietic, hepatic, and genetic damages and provided additional survival advantages. Hence, this study suggested that vanadium(III)-l-cysteine may offer potential therapeutic benefit in combination with cyclophosphamide by augmenting anticancer efficacy and

Pore-Size-Tuned Graphene Oxide Frameworks as Ion-Selective and Protective Layers on Hydrocarbon Membranes for Vanadium Redox-Flow Batteries.

Science.gov (United States)

Kim, Soohyun; Choi, Junghoon; Choi, Chanyong; Heo, Jiyun; Kim, Dae Woo; Lee, Jang Yong; Hong, Young Taik; Jung, Hee-Tae; Kim, Hee-Tak

2018-05-07

The laminated structure of graphene oxide (GO) membranes provides exceptional ion-separation properties due to the regular interlayer spacing ( d) between laminate layers. However, a larger effective pore size of the laminate immersed in water (∼11.1 Å) than the hydrated diameter of vanadium ions (>6.0 Å) prevents its use in vanadium redox-flow batteries (VRFB). In this work, we report an ion-selective graphene oxide framework (GOF) with a d tuned by cross-linking the GO nanosheets. Its effective pore size (∼5.9 Å) excludes vanadium ions by size but allows proton conduction. The GOF membrane is employed as a protective layer to address the poor chemical stability of sulfonated poly(arylene ether sulfone) (SPAES) membranes against VO 2 + in VRFB. By effectively blocking vanadium ions, the GOF/SPAES membrane exhibits vanadium-ion permeability 4.2 times lower and a durability 5 times longer than that of the pristine SPAES membrane. Moreover, the VRFB with the GOF/SPAES membrane achieves an energy efficiency of 89% at 80 mA cm -2 and a capacity retention of 88% even after 400 cycles, far exceeding results for Nafion 115 and demonstrating its practical applicability for VRFB.

Effects of Vanadium Ions in Different Oxidation States on Myosin ATPase Extracted from the Solitary Ascidian, Halocynthia roretzi (Drasche) : Biochemistry

OpenAIRE

HITOSHI, MICHIBATA; YUTAKA, ZENKO; KENJI, YAMADA; MASATO, HASEGAWA; TATSURO, TERADA; TAKAHARU, NUMAKUANI; Biological Institute, Faculty of Science, Toyama University; Biological Institute, Faculty of Science, Toyama University; Biological Institute, Faculty of Science, Toyama University; Biological Institute, Faculty of Science, Toyama University; Department of Chemistry, Toyama College of Technology; Marine Biological Station, Tohoku University

1989-01-01

Some ascidians are known to accumulate vanadium ion within their tissues by 10^6-fold as that in sea water and store the metal ion in its reduced tetravalent and/or trivalent states. It is also well known that phosphoenzymes are inhibited by pentavalent vanadium ion over a range of 10nM to 1mM. In the present experiment we have therefore examined the effects of vanadium ions in different oxidation states on the activity of myosin ATPase extracted from the mantle of the ascidian, Halocynthia r...

Organometallic benzene-vanadium wire: A one-dimensional half-metallic ferromagnet

DEFF Research Database (Denmark)

Maslyuk, V.; Bagrets, A.; Meded, V.

2006-01-01

Using density functional theory we perform theoretical investigations of the electronic properties of a freestanding one-dimensional organometallic vanadium-benzene wire. This system represents the limiting case of multidecker V-n(C6H6)(n+1) clusters which can be synthesized with established meth...

Roll-to-Roll Processing of Inverted Polymer Solar Cells using Hydrated Vanadium(V)Oxide as a PEDOT:PSS Replacement

DEFF Research Database (Denmark)

Martinez, Nieves Espinosa; Dam, Henrik Friis; Tanenbaum, David M.

2011-01-01

roll-to-roll (R2R) processing of all layers. The devices were prepared on flexible polyethyleneterphthalate (PET) and had the structure PET/ITO/ZnO/P3HT:PCBM/V2O5·(H2O)n/Ag. The ITO and silver electrodes were processed and patterned by use of screen printing. The zinc oxide, P3HT:PCBM and vanadium(V)oxide......The use of hydrated vanadium(V)oxide as a replacement of the commonly employed hole transporting material PEDOT:PSS was explored in this work. Polymer solar cells were prepared by spin coating on glass. Polymer solar cells and modules comprising 16 serially connected cells were prepared using full...... layers were processed by slot-die coating. The hydrated vanadium(V)oxide layer was slot-die coated using an isopropanol solution of vanadyl-triisopropoxide (VTIP). Coating experiments were carried out to establish the critical thickness of the hydrated vanadium(V)oxide layer by varying the concentration...

Determination of vanadium

International Nuclear Information System (INIS)

Stepin, V.V.; Kurbatova, V.I.; Fedorova, N.D.

1980-01-01

Techniques of vanadium determination in steels and alloys are developed. Extraction-photometric method with N-phenyl-benzohydroxamic acid when V content is 0.005-0.5% is suggested. Molar coefficient of the complex quenching at lambdasub(max)=530 nm constitutes 5750. Optimum concentration is 15-150 μg per 25 ml of the solution, determination limit is 0.05 μg/ml. Chloroform is an extracting agent. A photometric method with acetohydrazide of anthranilic acid is suggested for the analysis of alloyed steels at V content 0.03-1%. The lower limit of V determination constitutes 0.64 μg/ml. Effect of Fe is removed using phosphoric acid. Amperometric method for steels and alloys at V content from 0.05 to 5% and for steels and alloys containing more than 3% W and Cr is also developed. The method is based on amperometric titration with solution of double sulfuric salt of Fe(2) and ammonium [ru

Dissimilar laser welding of AISI 316L stainless steel to Ti6–Al4–6V alloy via pure vanadium interlayer

Energy Technology Data Exchange (ETDEWEB)

Tomashchuk, I., E-mail: iryna.tomashchuk@u-bourgogne.fr; Grevey, D.; Sallamand, P.

2015-01-12

Successful continuous laser joining of AISI 316L stainless steel with Ti6Al4V titanium alloy through pure vanadium interlayer has been performed. Three welding configurations were tested: one-pass welding involving all three materials and two pass and double spot welding involving creation of two melted zones separated by remaining solid vanadium. For the most relevant welds, the investigation of microstructure, phase content and mechanical properties has been carried out. In case of formation of a single melted zone, the insertion of steel elements into V-based solid solution embrittles the weld. In case of creation of two separated melted zones, the mechanical resistance of the junction is determined by annealing of remaining vanadium interlayer, which can be witnessed by observing the increase of grain size and decrease of UTS. The two pass configuration allows attain highest mechanical resistance: 367 MPa or 92% of UTS of annealed vanadium. Double spot configuration produces excessive heat supply to vanadium interlayer, which results in important decrease of tensile strength down to 72% of UTS of annealed vanadium. It was found that undesirable σ phase which forms between Fe and V is not created during the laser welding process because of high cooling rates. However, the zones whose composition corresponds to σ homogeneity range are crack-susceptible, so the best choice is to reduce the V content in steel/vanadium melted zone below σ phase formation limit. In the same time, the proportion between V and Ti in Ti6Al4V/vanadium melted zones does not influence mechanical properties as these elements form ideal solid solution.

Effects of the d-donor level of vanadium on the properties of Zn{sub 1−x}V{sub x}O films

Energy Technology Data Exchange (ETDEWEB)

García-Hemme, E., E-mail: eric.garcia@ucm.es [Dpto. de Física Aplicada III (Electricidad y Electrónica), Univ. Complutense de Madrid, Madrid 28040 (Spain); CEI Campus Moncloa, UCM-UPM, Madrid 28040 (Spain); Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Yu, K. M. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States); Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Wahnon, P. [CEI Campus Moncloa, UCM-UPM, Madrid 28040 (Spain); Instituto de Energía Solar and Depto TFB, E.T.S.I. Telecomunicación, Univ. Politécnica de Madrid, Ciudad Universitaria, Madrid 28040 (Spain); González-Díaz, G. [Dpto. de Física Aplicada III (Electricidad y Electrónica), Univ. Complutense de Madrid, Madrid 28040 (Spain); CEI Campus Moncloa, UCM-UPM, Madrid 28040 (Spain); Walukiewicz, W. [Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

2015-05-04

We report the effect of d-levels of vanadium atoms on the electronic band structure of ZnO. Polycrystalline layers of Zn{sub 1−x}V{sub x}O with 0 ≤ x ≤ 0.08 were synthesized using magnetron sputtering technique. Electrical measurements show that electron concentration increases with vanadium up to x = 0.04 and then decreases and films become insulating for x > 0.06. Optical characterization reveals that the absorption edge shifts to higher energy, while the photoluminescence (PL) peak shows a shift to lower energy with increasing vanadium content. This unusual optical behavior can be explained by an anticrossing interaction between the vanadium d-levels and the conduction band (CB) of ZnO. The interaction results in an upward shift of unoccupied CB (E{sub +}) and the downward shift of the fully occupied E{sub −} band derived from the vanadium d-levels. The composition dependence of optical absorption edge (E{sub +}) and PL peak (E{sub −}) can be fitted using the Band Anticrossing model with the vanadium d-level located at 0.13 eV below CB of ZnO and a coupling constant of 0.65 eV.

Novel sulfonated poly (ether ether keton)/polyetherimide acid-base blend membranes for vanadium redox flow battery applications

International Nuclear Information System (INIS)

Liu, Shuai; Wang, Lihua; Ding, Yue; Liu, Biqian; Han, Xutong; Song, Yanlin

2014-01-01

Highlights: • SPEEK/PEI acid-base blend membranes are prepared for VRB applications. • The acid-base blend membranes have much lower vanadium ion permeability. • The energy efficiency of SPEEK/PEI maintain around 86.9% after 50 cycles. - Abstract: Novel acid-base blend membranes composed of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared for vanadium redox flow battery (VRB). The blend membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electronic microscopy (SEM). The ion exchange capacity (IEC), proton conductivity, water uptake, vanadium ion permeability and mechanical properties were measured. As a result, the acid-base blend membranes exhibit higher water uptake, IEC and lower vanadium ion permeability compared to Nafion117 membranes and all these properties decrease with the increase of PEI. In VRB single cell test, the VRB with blend membranes shows lower charge capacity loss, higher coulombic efficiency (CE) and energy efficiency (EE) than Nafion117 membrane. Furthermore, the acid-base blend membranes present stable performance up to 50 cycles with no significant decline in CE and EE. All experimental results indicate that the SPEEK/PEI (S/P) acid-base blend membranes show promising prospects for VRB

Friedel–Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK Membranes for a Vanadium/Air Redox Flow Battery

Directory of Open Access Journals (Sweden)

Géraldine Merle

2013-12-01

Full Text Available Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone (cSPEEK membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel–Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a crosslinking on the sulfonic acid groups; and (b crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion.

Friedel–Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery

Science.gov (United States)

Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

2014-01-01

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel–Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion. PMID:24957118

Role of vanadium carbide traps in reducing the hydrogen embrittlement susceptibility of high strength alloy steels. Final report

Energy Technology Data Exchange (ETDEWEB)

Spencer, G.L.; Duquette, D.J.

1998-08-01

High strength alloy steels typically used for gun steel were investigated to determine their susceptibility to hydrogen embrittlement. Although AISI grade 4340 was quite susceptible to hydrogen embrittlement, ASTM A723 steel, which has identical mechanical properties but slightly different chemistries, was not susceptible to hydrogen embrittlement when exposed to the same conditions. The degree of embrittlement was determined by conducting notched tensile testing on uncharged and cathodically charged specimens. Chemical composition was modified to isolate the effect of alloying elements on hydrogen embrittlement susceptibility. Two steels-Modified A723 (C increased from 0.32% to 0.40%) and Modified 4340 (V increased from 0 to O.12%) were tested. X-ray diffraction identified the presence of vanadium carbide, V{sub 4}C{sub 3}, in A-23 steels, and subsequent hydrogen extraction studies evaluated the trapping effect of vanadium carbide. Based on these tests, it was determined that adding vanadium carbide to 4340 significantly decreased hydrogen embrittlement susceptibility because vanadium carbide traps ties up diffusible hydrogen. The effectiveness of these traps is examined and discussed in this paper.

Damage production by fast electrons in dilute alloys of vanadium, niobium and molybdenum

International Nuclear Information System (INIS)

Jung, P.

1975-01-01

Vanadium, niobium and molybdenum samples containing about 300 ppm of zirconium were irradiated at helium temperature with electrons of energies between 0,6 and 3.1 MeV. The measured damage rates were analysed in terms of minimum threshold energy, damage function and resistivity per unit concentration of Frenkel pairs. For the minimum threshold energy T(Sub)d, values of 25+-2 eV (V) 28+-2 e V(Nb) and 34+-2 e V(Mo) were obtained. Pronounced differences between the displacement functions of molybdenum and that of niobium and vanadium are found which are explained by different stability of the defects during the irradiation at helium temperature

Anisotropic Born-Mayer potential in lattice dynamics of Vanadium

International Nuclear Information System (INIS)

Onwuagba, B.N.

1988-01-01

A microscopic theory of the lattice dynamics of the transition metal vanadium is developed based on the Animalu's transition metal model potential (TMMP). The Born-Mayer potential associated with the distribution of the transition metal d-electrons is treated as anisotropic. Good agreement with experimental phonon dispersion curves longitudinal branches in the [111] direction

Capacity Decay Mitigation by Asymmetric Positive/Negative Electrolyte Volumes in Vanadium Redox Flow Batteries.

Science.gov (United States)

Park, Jong Ho; Park, Jung Jin; Park, O Ok; Yang, Jung Hoon

2016-11-23

Capacity decay in vanadium redox flow batteries during charge-discharge cycling has become an important issue because it lowers the practical energy density of the battery. The battery capacity tends to drop rapidly within the first tens of cycles and then drops more gradually over subsequent cycles during long-term operation. This paper analyzes and discusses the reasons for this early capacity decay. The imbalanced crossover rate of vanadium species was found to remain high until the total difference in vanadium concentration between the positive and negative electrolytes reached almost 1 mol dm -3 . To minimize the initial crossover imbalance, we introduced an asymmetric volume ratio between the positive and negative electrolytes during cell operation. Changing this ratio significantly reduced the capacity fading rate of the battery during the early cycles and improved its capacity retention at steady state. As an example, the practical energy density of the battery increased from 15.5 to 25.2 Wh L -1 simply after reduction of the positive volume by 25 %. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Random quaternary ammonium Diels-Alder poly(phenylene) copolymers for improved vanadium redox flow batteries

Science.gov (United States)

Largier, Timothy D.; Cornelius, Chris J.

2017-06-01

This study analyzes the effect of quaternary ammonium homopolymer (AmPP) and ionic and non-ionic random unit copolymerization (AmPP-PP) of Diels-Alder poly(phenylene)s on electrochemical and transport properties, vanadium redox flow battery performance, and material stability. AmPP-PP materials were synthesized with IEC's up to 2.2 meq/g, displaying a carbonate form ion conductivity of 17.3 mS/cm and water uptake of 57.3%. Vanadium ion permeability studies revealed that the random copolymers possess superior charge carrier selectivity. For materials of comparable ion content, at 10 mA/cm2 the random copolymer displayed a 14% increase in coulombic efficiency (CE) corresponding to a 7% increase in energy efficiency. All quaternary ammonium materials displayed ex situ degradation in a 0.5 M V5+ + 5 M H2SO4 solution, with the rate of degradation appearing to increase with IEC. Preliminary studies reveal that the neutralizing counter-ion has a significant effect on VRB performance, proportional to changes in vanadium ion molecular diffusion.

Mechanism of Enhancing Extraction of Vanadium from Stone Coal by Roasting with MgO