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  1. Ulogata na endoetelin-1 vo razvojot na dijabeticna nefropatija inducirana so streptozocin

    Directory of Open Access Journals (Sweden)

    Jasmina Trojacanec

    2006-06-01

    Full Text Available Dijabeticnata nefropatija pretstavuva edna od hronicnite mikrovaskularni komplikacii na dijabetot, so multifaktorijalna i ne do kraj rasvetlena etiopatogeneza. So ogled na toa sto kaj pacientite so dijabet, osobeno kaj onie so dijabeticna nefropatija, se najdeni zgolemeni vrednosti na endotelin-1, se pretpostavuva deka istiot moze da ima znacajna uloga vo razvojot na dijabeticnata nefropatija. Osnovna cel na nasata studija bese da se detektiraat promenite vo plazmatskoto nivo na endotelin-1 po eksperimentalno induciran dijabet, i dijabeticna nefropatija kaj staorci so streptozocin. So ogled na dobro poznatite efekti na AKE-inhibitorite, vo ovaa studija go ispituvavme i vlijanieto na enalapril (AKE inhibitor na plazmatskite koncentracii na endotelin-1, kako i negovite efekti vo tretmanot na dijabeti~na nefropatija. Ednokratnata i.p. administracija na streptozocin (STZ predizvika signifikantno zgolemuvanje na plazmatskite koncentracii na endotelin-1, proprateni so jasno izrazeni simptomi i znaci na dijabeticna nefropatija (mikroalbuminurija, zgolemeni urinarni vrednosti na N-acetyl-fl-D-glucosamidase, zgolemeni serumski koncentracii na urea, poliurija. Cetiri nedelniot tretman so enalapril dovede do signifikantno namaluvanje na plazmatskite koncentracii na endotelin-1 i do podobruvanje na simtomite i znacite na dijabeticnata nefropatija. Dobienite rezultati potvrduvaat deka endotelin-1 moze da ima znacajna uloga vo razvojot i progresijata na dijabeticnata nefropatija, a AKE inhibitorite, odnosno enalapril, mozat da ja ublazat i usporat progresijata na dijabeticnata nefropatija

  2. PRODUCCIÓN DE PROTEÍNA Y BIOMASA PROBIÓTICA DE Lactobacillus casei LIOFILIZADAS A PARTIR DE SUERO DE LECHE DE CABRA

    OpenAIRE

    E. J. Aguirre-Ezkauriatza; Ramírez-Medrano, A.; Aguilar-Yáñez, J. M.; M. M. Álvarez

    2009-01-01

    En este trabajo se documenta la factibilidad técnica de obtención de dos productos de valor agregado a partir de suero de leche de cabra: (a) proteína liofilizada y (b) biomasa probiótica liofilizada de Lactobacillus casei. Se presentan resultados de experimentos de ultrafiltración de suero de leche de cabra (SLC), del cual se retiene proteína con una alta relación proteína/lactosa. En su forma liofilizada, esta proteína presentó características de solubilidad superiores a productos comercial...

  3. Nov način simuliranja občutka vožnje

    OpenAIRE

    ZAJC, MATIC

    2015-01-01

    To diplomsko delo predstavlja nov način simuliranja občutka vožnje. V ta namen na trgu obstajajo različni simulatorji. Tem je skupno, da za generiranje sile uporabljajo gravitacijo, kar za seboj prinese številne omejitve, predvsem pri simuliranju dolgotrajnih pospeškov. Naš način simuliranja občutka vožnje pa deluje na principu generiranje sile na glavo uporabnika s pomočjo aktuatorjev. V prvem delu si bomo na kratko ogledali zgodovino razvoja simulatorjev. Simulatorji so bili v zadnjih de...

  4. Crystal structure and spectroscopic properties of Na2K6(VO)(2)(SO4)7

    DEFF Research Database (Denmark)

    Karydis, D.A.; Boghosian, S.; Nielsen, Kurt;

    2002-01-01

    Red-brown crystals of a new mixed alkali oxo sulfato vanadium(V) compound Na2K6(VO)(2)(SO4)(7), suitable for X-ray determination, have been obtained from the catalytically important binary molten salt system M2S2O7-V2O5 (M = 80% K and 20% Na). By slow cooling of a mixture with the mole fraction X...... equatorial V-O bonds in the range 1.881(6)-1.960-(6) A. The deformation of the VO6 octahedron is less pronounced compared to that of the known oxo sulfato V(V) compounds. Each VO3+ group is coordinated to five sulfate groups of which two are unidentately coordinated and three are bidentate bridging...... to neighboring VO3+ groups. The length of the S-O bonds in the S-O-V bridges of the two unidentately coordinated sulfato groups are 1.551(6) Angstrom and 1.568(6) Angstrom, respectively, which are unusually long compared to our earlier measurements of sulfate groups in other V(111), V(IV), and V(V) compounds....

  5. Thermodynamic analysis on the direct preparation of metallic vanadium from NaVO3 by molten salt electrolysis☆

    Institute of Scientific and Technical Information of China (English)

    Wei Weng; Mingyong Wang; Xuzhong Gong; Zhi Wang; Zhancheng Guo

    2016-01-01

    A novel and environmentally friendly route to directly prepare metallic vanadium from NaVO3 by molten salt electrolysis is proposed. The feasibility about the direct electro-reduction of NaVO3 to metallic vanadi-um is analyzed based on the thermodynamic calculations and experimental verifications. The theoretical decomposition voltage of NaVO3 to metallic vanadium is only 0.47 V at 800 °C and much lower than that of the alkali and alkali earth metal chloride salts. The value is slightly higher than that of low-valence vanadium oxides such as V2O3, V3O5 and VO. However, the low-valence vanadium oxides can be further electro-reduced to metallic vanadium thermodynamically. The thermodynamic analysis is verified by the experimental results. The direct preparation of metallic vanadium from NaVO3 by molten salt electrolysis is feasible.

  6. The alluaudite-type crystal structures of Na2(Fe/Co2Co(VO43 and Ag2(Fe/Co2Co(VO43

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    Mohammed Hadouchi

    2016-07-01

    Full Text Available Single crystals of the title compounds, disodium di(cobalt/iron cobalt tris(orthovanadate, Na2(Fe/Co2Co(VO43, and disilver di(cobalt/iron cobalt tris(orthovanadate, Ag2(Fe/Co2Co(VO43, were grown from a melt consisting of stoichiometric mixtures of three metallic cation precursors and vanadium pentoxide. The difficulty to distinguish between cobalt and iron by using X-ray diffraction alone forced us to explore several models, assuming an oxidation state of +II for Co and +III for Fe and a partial cationic disorder in the Wyckoff site 8f containing a mixture of Co and Fe with a statistical distribution for the Na compound and an occupancy ratio of 0.4875:0.5125 (Co:Fe for the Ag compound. The alluaudite-type structure is made up from [10-1] chains of [(Co,Fe2O10] double octahedra linked by highly distorted [CoO6] octahedra via a common edge. The chains are linked through VO4 tetrahedra, forming polyhedral sheets perpendicular to [010]. The stacking of the sheets defines two types of channels parallel to [001] where the Na+ cations (both with full occupancy or Ag+ cations (one with occupancy 0.97 are located.

  7. Biomasa en Chile

    OpenAIRE

    Nilsson Cifuentes, Gabriel; Rodríguez Monroy, Carlos

    2012-01-01

    El artículo presenta el desarrollo de la biomasa en Chile, dentro del complejo marco energético existente en el país, el cual, aún no logra potenciar e incentivar el desarrollo de energías renovables y depende fuertemente de los combustibles fósiles, acrecentando el riesgo latente de sufrir una crisis energética, en el mediano plazo, producto de la paulatina incorporación de nuevas centrales generadoras de energías, que satisfagan la creciente demanda energética pronosticada. Este ar...

  8. EIS Evaluation of Fe, Cr, and Ni in NaVO3 at 700°C

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    O. Sotelo-Mazón

    2014-01-01

    Full Text Available Due to the depletion of high-grade fuels and for economic reasons, use of residual fuel oil in energy generation systems is a common practice. Residual fuel oil contains sodium, vanadium, and sulphur as impurities, as well as NaCl contamination. Metallic dissolution caused by molten vanadates has been classically considered the main corrosion process involved in the degradation of alloys exposed to the combustion products of heavy fuel oils. Iron and nickel base alloys are the commercial alloys commonly used for the high temperature applications, for example, manufacture of components used in aggressive environments of gas turbines, steam boilers, and so forth. Therefore, because the main constituents of these materials are Fe, Cr, and Ni, where Cr is the element responsible for providing the corrosion resistance, in this study the electrochemical performance of Fe, Cr, and Ni in NaVO3 at 700°C in static air for 100 hours was evaluated.

  9. The alluaudite-type crystal structures of Na2(Fe/Co)2Co(VO4)3 and Ag2(Fe/Co)2Co(VO4)3

    Science.gov (United States)

    Hadouchi, Mohammed; Assani, Abderrazzak; Saadi, Mohamed; El Ammari, Lahcen

    2016-01-01

    Single crystals of the title compounds, disodium di(cobalt/iron) cobalt tris­(orthovanadate), Na2(Fe/Co)2Co(VO4)3, and disilver di(cobalt/iron) cobalt tris­(orthovanadate), Ag2(Fe/Co)2Co(VO4)3, were grown from a melt consisting of stoichiometric mixtures of three metallic cation precursors and vanadium pentoxide. The difficulty to distinguish between cobalt and iron by using X-ray diffraction alone forced us to explore several models, assuming an oxidation state of +II for Co and +III for Fe and a partial cationic disorder in the Wyckoff site 8f containing a mixture of Co and Fe with a statistical distribution for the Na compound and an occupancy ratio of 0.4875:0.5125 (Co:Fe) for the Ag compound. The alluaudite-type structure is made up from [10-1] chains of [(Co,Fe)2O10] double octa­hedra linked by highly distorted [CoO6] octa­hedra via a common edge. The chains are linked through VO4 tetra­hedra, forming polyhedral sheets perpendicular to [010]. The stacking of the sheets defines two types of channels parallel to [001] where the Na+ cations (both with full occupancy) or Ag+ cations (one with occupancy 0.97) are located. PMID:27555954

  10. Inclusão do equivalente energético do lactato na regressão VO2-intensidade em corrida horizontal e inclinada (10,5%

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    Victor Machado REIS

    Full Text Available Resumo O estudo teve por objetivo analisar o efeito da adição do equivalente energético do lactato sanguíneo com a medida de VO2 durante a corrida em esteira horizontal (0% e inclinada (10,5%, como forma de estimativa do custo energético da corrida. Treze corredores de meia e longa distância (idade 28,1 ± 4,2 anos; estatura 1,75 ± 0,07 m; massa corporal 65,2 ± 4,9 kg; VO2max 70,3 ± 4,9 ml·kg-1·min-1 cumpriram dois testes em esteira rolante (0% e 10,5% que incluíram vários estágios em intensidade constante. Foram calculadas para cada atleta as regressões VO2-velocidade, bem como regressões alternativas com a adição de um equivalente energético de 3 ml O2 Eq·kg-1·mM [La-] às medições de VO2. Não se verificou interação significativa entre a adição do equivalente do lactato e a inclinação da esteira. A ANOVA indicou um efeito significativo da adição do equivalente do lactato na inclinação da reta de regressão e na estimativa do custo energético. Os tamanhos do efeito obtidos indicam que este efeito é mais forte na corrida horizontal. Estes resultados sugerem que em testes laboratoriais com corredores treinados se deverá considerar a adição dos valores de VO2 com os equivalentes energéticos do lactato.

  11. Hot corrosion behaviour of Fe-Al based intermetallic in molten NaVO{sub 3} salt

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Medina, M.A. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, C.P. 07730 Mexico, D.F. (Mexico)], E-mail: maespin@imp.mx; Carbajal-De la Torre, G. [Facultad de Ingenieria Mecanica, UMSNH, Santiago Tapia 403 Col. Centro, C.P. 58098 Morelia, Michoacan (Mexico); Liu, H.B. [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, C.P. 07730 Mexico, D.F. (Mexico); Martinez-Villafane, A. [CIMAV, Complejo Industrial Chihuahua, Chihuahua (Mexico); Gonzalez-Rodriguez, J.G. [CIMAV, Complejo Industrial Chihuahua, Chihuahua (Mexico); UAEM-CIICAP, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos (Mexico)

    2009-06-15

    The hot corrosion of sprayed Fe-40 (at.%)Al intermetallic alloy with additions of boron and alumina whiskers in molten NaVO{sub 3} at 700 deg. C has been evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy, EIS, techniques. For short exposure times, the corrosion mechanism under these conditions was observed to be controlled by an activation process, whereas for longer exposure times, the corrosion process was under diffusion control due to the growing of an Al{sub 2}O{sub 3} oxide scale, which made the diffusion of both reducing and oxidizing species through the scale to the alloy or scale surfaces more difficult. Equivalent electric model used to simulate the EIS data showed that a finite length Warburg diffusion could properly characterize the diffusion process, which confirmed the formation of a compact corrosion product scales containing rich aluminium oxide. Thus, the corrosion process was under diffusion control of aggressive ions through the formed scale. The electrochemical study was complemented by scanning electronic microscopy characterization and micro chemical analysis.

  12. Experimental investigation of the EPR parameters and molecular orbital bonding coefficients for VO{sup 2+} ion in NaH{sub 2}PO{sub 4}·2H{sub 2}O single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kalfaoğlu, Emel [Ondokuz Mayıs University, Faculty of Sciences, Department of Physics, 55139 Kurupelit-Samsun (Turkey); Karabulut, Bünyamin, E-mail: bbulut@omu.edu.tr [Ondokuz Mayıs University, Faculty of Engineering, Department of Computer Engineering, 55139 Kurupelit-Samsun (Turkey)

    2016-09-15

    Electron paramagnetic resonance (EPR) spectra of VO{sup 2+} ions in NaH{sub 2}PO{sub 4}·2H{sub 2}O single crystal have been studied. The spin-Hamiltonian parameters and molecular orbital bonding coefficients were calculated. The angular variation of the EPR spectra shows two different VO{sup 2+} complexes. These are located in different chemical environment and each environment contains four magnetically inequivalent VO{sup 2+} sites. The crystal field around VO{sup 2+} ion is approximately axially symmetric since a strong V=O bond distorts the crystal lattice. Spin Hamiltonian parameters and molecular orbital bonding coefficients were calculated from the EPR data and the nature of bonding in the complex was discussed together.

  13. Experimental investigation of the EPR parameters and molecular orbital bonding coefficients for VO2+ ion in NaH2PO4·2H2O single crystals

    Science.gov (United States)

    Kalfaoğlu, Emel; Karabulut, Bünyamin

    2016-09-01

    Electron paramagnetic resonance (EPR) spectra of VO2+ ions in NaH2PO4·2H2O single crystal have been studied. The spin-Hamiltonian parameters and molecular orbital bonding coefficients were calculated. The angular variation of the EPR spectra shows two different VO2+ complexes. These are located in different chemical environment and each environment contains four magnetically inequivalent VO2+ sites. The crystal field around VO2+ ion is approximately axially symmetric since a strong V=O bond distorts the crystal lattice. Spin Hamiltonian parameters and molecular orbital bonding coefficients were calculated from the EPR data and the nature of bonding in the complex was discussed together.

  14. Efeitos do estado e especificidade do treinamento aeróbio na relação %VO2max versus %FCmax durante o ciclismo Effects of the state and specificity of aerobic training on the %VO2max versus %HRmax ratio during cycling

    Directory of Open Access Journals (Sweden)

    Fabrizio Caputo

    2005-01-01

    Full Text Available OBJETIVO: Determinar os efeitos do estado e especificidade de treinamento aeróbio na relação entre o percentual do consumo máximo de oxigênio (%VO2max e o percentual da frequência cardíaca máxima (%FCmax durante o exercício incremental realizado no cicloergômetro. MÉTODOS: Sete corredores, 9 ciclistas, 11 triatletas e 12 sedentários, todos do sexo masculino e aparentemente saudáveis, foram submetidos a um teste incremental até a exaustão no cicloergômetro. Regressões lineares entre %VO2max e %FCmax foram determinadas para cada indivíduo. Com base nessas regressões, foram calculados %FCmax correspondentes a determinados %VO2max (50, 60, 70, 80 e 90% de cada participante. RESULTADOS: Não foram encontradas diferenças significantes entre todos os grupos nos %FCmax para cada um dos %VO2max avaliados. Analisando-se os voluntários como um único grupo, as médias dos %FCmax correspondentes a 50, 60, 70, 80 e 90% %VO2max foram 67, 73, 80, 87, e 93%, respectivamente. CONCLUSÃO: Nos grupos analisados, a relação entre o %VO2max e %FCmax durante o exercício incremental no ciclismo não é dependente do estado e especificidade do treinamento aeróbio.OBJECTIVE: To determine the effects of the status and specificity of exercise training in the ratio between maximum oxygen consumption (%VO2max and the percentage of maximal heart rate (%HRmax during incremental exercise on a cycle ergometer. METHODS: Seven runners, 9 cyclists, 11 triathletes, and 12 sedentary individuals, all male and apparently healthy, underwent exhaustive incremental exercise on cycle ergometers. Linear regressions between %VO2max x %HRmax were determined for each individual. Based on these regressions, %HRmax was assessed corresponding to a determined %VO2max (50, 60, 70, 80, and 90% from each participant. RESULTS: Significant differences were not found between the groups in %HRmax for each of the %VO2max assessed. Analyzing the volunteers as a single group, the

  15. Crystal structure of (Na0.70(Na0.70,Mn0.30(Fe3+,Fe2+2Fe2+(VO43, a sodium-, iron- and manganese-based vanadate with the alluaudite-type structure

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    Elhassan Benhsina

    2016-02-01

    Full Text Available The title compound, sodium (sodium,manganese triiron(II,III tris[vanadate(V], (Na0.70(Na0.70,Mn0.30(Fe3+,Fe2+2Fe2+(VO43, was prepared by solid-state reactions. It crystallizes in an alluaudite-like structure, characterized by a partial cationic disorder. In the structure, four of the 12 sites in the asymmetric unit are located on special positions, three on a twofold rotation axis (Wyckoff position 4e and one on an inversion centre (4b. Two sites on the twofold rotation axis are entirely filled by Fe2+ and V5+, whereas the third site has a partial occupancy of 70% by Na+. The site on the inversion centre is occupied by Na+ and Mn2+ cations in a 0.7:0.3 ratio. The remaining Fe2+ and Fe3+ atoms are statistically distributed on a general position. The three-dimensional framework of this structure is made up of kinked chains of edge-sharing [FeO6] octahedra stacked parallel to [10-1]. These chains are held together by VO4 tetrahedral groups, forming polyhedral sheets perpendicular to [010]. Within this framework, two types of channels extending along [001] are present. One is occupied by (Na+/Mn2+ while the second is partially occupied by Na+. The mixed site containing (Na+/Mn2+ has an octahedral coordination sphere, while the Na+ cations in the second channel are coordinated by eight O atoms.

  16. A detailed study of the dehydration process in synthetic strelkinite, Na[(UO{sub 2})(VO{sub 4})] . nH{sub 2}O (n = 0, 1, 2)

    Energy Technology Data Exchange (ETDEWEB)

    Suleimanov, Evgeny V.; Somov, Nikolay V.; Chuprunov, Evgeny V.; Mayatskikh, Ekaterina F. [Nizhny Novgorod State Univ. (Russian Federation); Depmeier, Wulf [Kiel Univ. (Germany). Inst. fuer Geowissenschaften; Alekseev, Evgeny V. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energie- und Klimaforschung (IEK-6)

    2012-11-01

    Synthetic strelkinite Na[(UO{sub 2})(VO{sub 4})] . nH{sub 2}O (n = 0, 1, 2) was systematically investigated by single crystal X-ray diffraction and thermoanalytical methods. The anhydrous form and two hydrates were isolated as single crystals and the structures of these phases solved: Na[(UO{sub 2})(VO{sub 4})], monoclinic, P2{sub 1}/c, a = 6.0205(1) Aa, b = 8.3365(1) Aa, c = 10.4164(2) Aa, {beta} = 100.466(2) , V = 514.10(1) Aa{sup 3}, R{sub 1} = 0.0337; Na[(UO{sub 2})(VO{sub 4})] . H{sub 2}O, monoclinic, P2{sub 1}/c, a = 7.722(2) Aa, b = 8.512(1) Aa, c = 10.480(4) Aa, {beta} = 113.18(3) , V = 633.3(3) Aa{sup 3}, R{sub 1} = 0.1658; Na[(UO{sub 2})(VO{sub 4})] . 2 H{sub 2}O, monoclinic, P2{sub 1}/n, a = 16.2399(5) Aa, b = 8.2844(2) Aa, c = 10.5011(2) Aa, {beta} = 97.644(2) , V = 1400.24(6) Aa{sup 3}, R{sub 1} = 0.0776. A possible mechanism of the structural transformation processes during dehydration is proposed based on the structures of the anhydrous phase and the hydrates. (orig.)

  17. RELACIÓN BIOMASA DE RAÍZ/BIOMASA TOTAL DE SOJA (Glycine max EN DOS SISTEMAS DE LABRANZA

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    Mónica Beatriz Barrios

    2014-06-01

    Full Text Available La soja es el principal cultivo en Argentina debido a su adaptación a los suelos, la incorporación de tecnología con el empleo de la siembra directa y el precio del mercado internacional. Las propiedades físicas, químicas y biológicas de cada suelo se ven modificadas por el tipo de sistema de laboreo empleado. El entorno generado por la labranza altera el crecimiento y el equilibrio funcional de los cultivos herbáceos. En el año 2006, se instaló un ensayo en el Partido de Ezeiza (Pampa Ondulada, con el objetivo de evaluar los efectos del sistema de laboreo en el equilibrio funcional entre biomasa de raíces/biomasa total en soja (Glycine max durante la campaña 2012/2013. Se utilizó un diseño de bloques completos al azar con dos tratamientos que consistieron en: labranza convencional (LC y siembra directa (SD, con cuatro repeticiones. Se midió: peso de biomasa aérea, área foliar, rendimiento en grano, peso de raíces de 0-10 y 10-20 cm de profundidad, y se calculó biomasa total y la relación biomasa de raíces/biomasa total. El peso de raíces se determinó con el método del cilindro, el área foliar con el paquete estadístico Iproplus y el rendimiento con el cuadrado de corte. Los datos obtenidos fueron sometidos a análisis de varianza y las medias de los tratamientos fueron comparadas según Tukey (P < 0.05. El efecto del sistema de labranza generó diferentes respuestas en función de la variable evaluada y la fecha de muestreo. LC resultó significativamente superior (P < 0.05 respecto a SD en biomasa total y biomasa aérea en las etapas fenológicas R3 y R5; biomasa de raíces en R1 y R3; IAF en R2, R3 y R5. El rendimiento en grano fue mayor en LC respecto de SD, sin embargo el sistema de labranza no afectó la relación biomasa de raíz/biomasa total.

  18. Polymorphism of NaVO2F2: a P2₁/c superstructure with pseudosymmetry of P2₁/m in the subcell.

    Science.gov (United States)

    Yu, Zi-Qun; Wang, Jing-Quan; Huang, Ya-Xi; Botis, Sanda M; Pan, Yuanming; Mi, Jin-Xiao

    2015-06-01

    The ADDSYM routine in the program PLATON [Spek (2015). Acta Cryst. C71, 9-18] has helped researchers to avoid structures of (metal-)organic compounds being reported in an unnecessarily low symmetry space group. However, determination of the correct space group may get more complicated in cases of pseudosymmetric inorganic compounds. One example is NaVO2F2, which was reported [Crosnier-Lopez et al. (1994). Eur. J. Solid State Inorg. Chem. 31, 957-965] in the acentric space group P2₁ based on properties but flagged by ADDSYM as (pseudo)centrosymmetric P2₁/m within default distance tolerances. Herein a systematic investigation reveals that NaVO2F2 exists in at least four polymorphs: P2₁, (I), P2₁/m, (II), P2₁/c, (III), and one or more low-temperature ones. The new centrosymmetric modification, (III), with the space group P2₁/c has a similar atomic packing geometry to phase (I), except for having a doubled c axis. The double-cell of phase (III) arises from atomic shifts from the glide plane c at (x, ¼, z). With increasing temperature, the number of observed reflections decreases. The odd l reflections gradually become weaker and, correspondingly, all atoms shift towards the glide plane, resulting in a gradual second-order transformation of (III) into high-temperature phase (II) (P2₁/m) at below 493 K. At least one first-order enantiotropic phase transition was observed below 139 K from both the single-crystal X-ray diffraction and the differential scanning calorimetry analyses. Periodic first-principles calculations within density functional theory show that both P2₁/c superstructure (III) and P2₁ substructure (I) are more stable than P2₁/m structure (II), and that P2₁/c superstructure (III) is more stable that P2₁ substructure (I).

  19. Selección de una levadura para la producción de biomasa: crecimiento en suero de queso

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    Wendy Zumbado-Rivera

    2006-01-01

    Full Text Available El presente proyecto se realizó con el objetivo de recomendar una especie de levadura para la producción de biomasa, utilizando como sustrato el suero de leche del proceso de elaboración de queso blanco tipo Turrialba. Se compararon las especies Kluyveromyces marxianus, Candida kefyr y Saccharomyces cerevisiae por medio de su crecimiento en un sistema de fermentación por lotes. Se determinó el tiempo de fermentación, la productividad total y el contenido de proteína de la biomasa. Al comparar la variación en el tiempo según la levadura utilizada, se obtuvo diferencias significativas (p ≤ 0,05. Las levaduras K. marxianus y C. kefyr presentaron un tiempo de 19 y 18 horas, respectivamente y S. cerevisiae, un tiempo de 24 horas. Con respecto a la productividad total de biomasa, la especie K. marxianus presentó un valor de 0,22 g/lxh, resultando significativamente diferente (p ≤ 0,05 a las especies C. kefyr y S. cerevisiae, para las cuales se obtuvieron productividades de 0,14 y 0,13 g/lxh. La variación en el contenido de proteína de acuerdo con la levadura utilizada no resultó significativo (p ≥ 0,05. Para la especie K. marxianus se obtuvo un contenido de proteína de 32%, 34% para C. kefyr y 35% para S. cerevisiae. Se seleccionó la especie de levadura Kluyveromyces marxianus para la producción de proteína unicelular, por presentar un menor tiempo de fermentación, mayor productividad e igual contenido proteico de la biomasa que las otras levaduras, además de facilidades de utilización

  20. Componentes químicos y biomasa de Ulva fasciata (Chlorophyta) en la costa Norte de la Ciudad de La Habana, Cuba

    OpenAIRE

    Mercedes Cano Mallo; Jhoana Díaz Larrea; Olga Valdés Iglesias; Isabel Bustio

    2007-01-01

    El objetivo de este trabajo fue determinar el porcentaje de los componentes químicos (proteínas, carbohidratos, fibra, lípidos, cenizas y la relación proteína:carbohidratos) y la biomasa de Ulva fasciata Delile (Chlorophyta), en un sector de la costa Norte de la Ciudad de La Habana entre los ríos Quibú y Jaimanitas. Se evaluó la variación espacial y temporal de los componentes entre mayo de 1998 y julio de 1999 y la biomasa entre febrero de 1999 y enero del 2001. Se escogieron para realizar l...

  1. A phase-transfer assisted solvo-thermal strategy for low-temperature synthesis of Na3(VO1-xPO4)2F1+2x cathodes for sodium-ion batteries.

    Science.gov (United States)

    Zhao, Junmei; Mu, Linqin; Qi, Yuruo; Hu, Yong-Sheng; Liu, Huizhou; Dai, Sheng

    2015-04-28

    We demonstrate that a series of high-performance cathode materials, sodium vanadium polyanionic compounds, Na3(VO1-xPO4)2F1+2x (x = 0, 0.5 and 1), can be synthesized by a phase-transfer assisted solvo-thermal strategy at a rather low temperature (80-140 °C) in one simple step, exhibiting a high Na storage capacity of ca. 120 mA h g(-1) and excellent cycling performance. This study makes a significant step to extend this strategy to the synthesis of functional materials from simple binary to complex multicomponent compounds.

  2. Enriquecimiento de biomasa de levadura con micronutrientes esenciales

    OpenAIRE

    2008-01-01

    Se estudian las potencialidades de enriquecimiento de la biomasa de levaduras GRAS a partir de medios de cultivo ricos en micronutrientes de interés, básicamente, cromo y selenio. La levadura tiene la propiedad de incorporar a su biomasa cantidades elevadas de componentes del medio aún cuando no se utilicen metabólicamente. Las dietas diarias actuales, incluso en los países desarrollados, son regularmente deficitarias en Se y Cr, elementos esenciales para el comportamiento metabólico estable....

  3. Hydrothermal preparation of BiVO{sub 4} powders

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jingbing; Wang Hao; Wang Shu; Yan Hui

    2003-11-15

    Monoclinic bismuth vanadate (BiVO{sub 4}) powders were prepared by a mild hydrothermal method, using an aqueous solution of bismuth nitrate and two different vanadium sources (V{sub 2}O{sub 5} and NaVO{sub 3}). The characterization of as-prepared BiVO{sub 4} was carried out by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The results revealed that in the present work the temperature of 200 and 140 deg. C are sufficient to prepare phase pure BiVO{sub 4} powders from V{sub 2}O{sub 5} and NaVO{sub 3}, respectively. The BiVO{sub 4} sample prepared from V{sub 2}O{sub 5} consists of an agglomeration of small rod-like particles. When BiVO{sub 4} was prepared from NaVO{sub 3}, monoclinic BiVO{sub 4} powder with a plate form is obtained.

  4. Efeito do tempo de intervalo da amostra ventilatória na variabilidade do consumo máximo de oxigênio (VO2 máx em jogadores de futebol profissional

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos Silva

    1999-04-01

    Full Text Available O propósito deste estudo foi verificar, em futebolistas profissionais, o impacto de sete intervalos de tempo sobre a variável fisiológica consumo máximo de oxigênio (VO2 máx. Dezoito jogadores de futebol com média de idade de 24 ± 4 anos (18-31, peso de 72,5 ± 5,9kg (62-83 e estatura de 176,5 ± 7,0cm (164-188 foram submetidos a teste ergométrico máximo em esteira rolante, utilizando-se protocolo escalonado contínuo. A resposta de freqüência cardíaca (FC foi registrada por meio de um eletrocardiógrafo computadorizado de 12 derivações simultâneas. A ventilação pulmonar (V E, o consumo de oxigênio (VO2, a produção de dióxido de carbono (VCO2 e a razão de troca respiratória (RER foram calculadas a partir de valores medidos por um sistema espirométrico computadorizado. Os resultados deste estudo demonstraram que houve variabilidade significante do VO2 máx (p < 0,05 somente quando se comparou a resposta instantânea respiração-a-respiração (breath-by-breath em relação aos outros intervalos de tempos analisados (10, 20, 30, 40, 50 e 60 segundos, respectivamente. Concluindo, durante o exercício de intensidade progressiva, observou-se que o aumento do VO2 foi proporcional à diminuição do intervalo de tempo da coleta ventilatória. O tempo de intervalo maior subestimou esse aumento. Assim, sugere-se que o avaliador utilize intervalos médios na faixa de tempo entre 10 e 60 segundos, pois não foi verificada diferença estatística significante entre esses intervalos.

  5. Proyecto de una central eléctrica de biomasa

    OpenAIRE

    Valentín Botija, Sergio

    2011-01-01

    El presente Proyecto de fin de carrera pretende dar una respuesta técnica a la necesidad de abastecimiento e independencia energética mediante una solución basada en las energías renovables y en combustibles vegetales, en concreto aquella basada en la biomasa; así como profundizar en el conocimiento de las mismas y realizar un estudio de viabilidad de estas técnicas en una zona determinada de Castilla-La Mancha. De modo, que mediante este PFC se trata de analizar la viabilidad técnica y econó...

  6. Handleiding benchmark VO

    NARCIS (Netherlands)

    Blank, j.l.t.

    2008-01-01

    OnderzoeksrapportenArchiefTechniek, Bestuur en Management> Over faculteit> Afdelingen> Innovation Systems> IPSE> Onderzoek> Publicaties> Onderzoeksrapporten> Handleiding benchmark VO Handleiding benchmark VO 25 november 2008 door IPSE Studies Door J.L.T. Blank. Handleiding voor het lezen van de i

  7. Crystal structure of (Na0.70)(Na0.70,Mn0.30)(Fe3+,Fe2+)2Fe2+(VO4)3, a sodium-, iron- and manganese-based vanadate with the alluaudite-type structure

    Science.gov (United States)

    Benhsina, Elhassan; Assani, Abderrazzak; Saadi, Mohamed; El Ammari, Lahcen

    2016-01-01

    The title compound, sodium (sodium,manganese) triiron(II,III) tris[vana­date(V)], (Na0.70)(Na0.70,Mn0.30)(Fe3+,Fe2+)2Fe2+(VO4)3, was prepared by solid-state reactions. It crystallizes in an alluaudite-like structure, characterized by a partial cationic disorder. In the structure, four of the 12 sites in the asymmetric unit are located on special positions, three on a twofold rotation axis (Wyckoff position 4e) and one on an inversion centre (4b). Two sites on the twofold rotation axis are entirely filled by Fe2+ and V5+, whereas the third site has a partial occupancy of 70% by Na+. The site on the inversion centre is occupied by Na+ and Mn2+ cations in a 0.7:0.3 ratio. The remaining Fe2+ and Fe3+ atoms are statistically distributed on a general position. The three-dimensional framework of this structure is made up of kinked chains of edge-sharing [FeO6] octa­hedra stacked parallel to [10-1]. These chains are held together by VO4 tetra­hedral groups, forming polyhedral sheets perpendicular to [010]. Within this framework, two types of channels extending along [001] are present. One is occupied by (Na+/Mn2+) while the second is partially occupied by Na+. The mixed site containing (Na+/Mn2+) has an octa­hedral coordination sphere, while the Na+ cations in the second channel are coordinated by eight O atoms. PMID:26958392

  8. A three-dimensional structure of vanadium malonate: synthesis, characterization and X-ray structure of [Na 2VO(C 3H 2O 4) 2(H 2O) 2] n

    Science.gov (United States)

    Zhang, Quan-Zheng; Lu, Can-Zhong; Yang, Wen-Bin; Chen, Shu-Mei; Yu, Ya-Qin

    2004-05-01

    A three-dimensional structure [Na 2VO(C 3H 2O 4) 2(H 2O) 2] n was synthesized from the aqueous solution of V 2O 5, malonic acid and HCl. The compound crystallizes in orthorhombic system, space group C222 1 with a=7.2472(9) Å, b=15.9465(2) Å, c=10.3672(1) Å, V=1198.1(3) Å 3, Z=4, and R1=0.0242 for 1027 observed reflections. Single crystal X-ray diffraction reveals that the vanadium atom is coordinated by six oxygen atoms in an octahedral geometry. It is more interesting that one sodium ion is coordinated by two μ 3-OH 2 and six carboxyl oxygen atoms, which exhibits an unusual coordination mode. The malonato-vanadium units are linked up by two sodium ions to an extended network

  9. VO2 pico e inclinação VE/VCO2 na era dos betabloqueadores na insuficiência cardíaca: uma experiência brasileira Peak VO2 and VE/VCO2 slope in betablockers era in patients with heart failure: a brazilian experience

    Directory of Open Access Journals (Sweden)

    Guilherme Veiga Guimarães

    2008-07-01

    Full Text Available FUNDAMENTO: Estudos têm demonstrado que o consumo de oxigênio de pico (VO2 pico e a inclinação VE/VCO2 são preditores de sobrevida em pacientes com insuficiência cardíaca (IC. Entretanto, com a adição do betabloqueador no tratamento da IC, os valores de prognóstico do VO2 pico e da Inclinação VE/VCO2 não estão totalmente estabelecidos. OBJETIVO: Avaliar o efeito dos betabloqueadores no valor de prognóstico do VO2 pico e da inclinação VE/VCO2 em pacientes com IC. MÉTODOS: Estudamos 391 pacientes com insuficiência cardíaca, com idade de 49 ± 14 anos e fração de ejeção do ventrículo esquerdo de 38 ± 10%. Total de pacientes que usavam (grupo I - GI e não usavam (grupo II - GII betabloqueadores: 229 e 162, respectivamente. Todos os pacientes foram submetidos a teste de esforço cardiopulmonar, em esteira, usando o protocolo de Naughton. RESULTADOS: O VO2 pico 16 ml.kg-1.min-1 categorizaram pacientes com melhor prognóstico em médio prazo. A faixa do VO2 pico entre > 10 e BACKGROUND: Studies have demonstrated that peak oxygen consumption (peak VO2 and the VE/VCO2 slope are predictors of survival in patients with heart failure (HF. However, with the advent of betablockers in the treatment of HF, the prognostic values of peak VO2 and VE/VCO2 slope have not been fully established. OBJECTIVE: To evaluate the effect of betablocker use on the prognostic value of peak VO2 and VE/VCO2 slope in patients with HF. METHODS: We studied 391 patients with heart failure, aged 49 ± 14 years and presenting a left ventricular ejection fraction of 38 ± 10%. The total number of patients that used (Group I - GI or did not use (Group II - GII betablockers was 229 and 162, respectively. All patients were submitted to a cardiopulmonary stress test on a treadmill, using the Naughton protocol. RESULTS: A peak VO2 16 ml.kg-1.min-1 categorizes patients with a better mid-term prognosis. Peak VO2 values between > 10 and < 16 ml.kg-1.min-1 indicated

  10. Enriquecimiento de biomasa de levadura con micronutrientes esenciales

    Directory of Open Access Journals (Sweden)

    Miguel A. Otero

    2008-01-01

    Full Text Available Se estudian las potencialidades de enriquecimiento de la biomasa de levaduras GRAS a partir de medios de cultivo ricos en micronutrientes de interés, básicamente, cromo y selenio. La levadura tiene la propiedad de incorporar a su biomasa cantidades elevadas de componentes del medio aún cuando no se utilicen metabólicamente. Las dietas diarias actuales, incluso en los países desarrollados, son regularmente deficitarias en Se y Cr, elementos esenciales para el comportamiento metabólico estable. El Cr es un componente del Factor de Tolerancia a la Glucosa (GTF que facilita las funciones de la insulina. Por medio de las técnicas del batch incrementado se puede llegar a concentraciones de Cr y Se de hasta 1000 ppm. Los productos puede ser empleado en la prevención y profilaxis de la Diabetes mellitus, en su variante senil, en tanto que el Se juega un rol antioxidante primordial.

  11. BIOMASA EN PLANTACIONES DE Eucalyptus viminalis Labill. DE LA PROVINCIA DE BUENOS AIRES, ARGENTINA

    Directory of Open Access Journals (Sweden)

    Paula Ferrere

    2008-01-01

    Full Text Available El presente trabajo se desarrolló en el oeste de la provincia de Buenos Aires, Argentina con el objetivo de ajustar funciones de biomasa de árboles individuales y determinar la biomasa en diferentes compartimientos de la planta y el sotobosque. Se identificaron rodales de Eucalyptus viminalis Labill. cuyas edades oscilaron entre 4 y 14 años. Se apearon 21 árboles con diámetros entre 9,2 y 32,5 cm. Se desarrollaron regresiones simples y múltiples y se estimó el volumen, la biomasa en ramas, hojas y fuste. Las ecuaciones de volumen de mejor comportamiento son basadas en modelos lineales en su forma normal, y el modelo más adecuado fue el que incorporó al d2 (R2 = 0,92. Para la estimación de la biomasa en hojas, ramas, copa y fuste se recomienda los modelos ln-ln que consideran el d y h o solo el d. El componente de la biomasa en hojas presentó una estimación más débil. La distribución de la biomasa en los individuos sigue el patrón de desarrollo que se encuentra en la bibliografía. La proporción de la biomasa en la copa disminuye con la edad, contrariamente a lo sucedido con el fuste.

  12. Solid Biomass Consumption in Households and Greenhouse Gas Emission Reduction in Latvia / CIETĀS Biomasas PATĒRIŅŠ un SILTUMNĪCEFEKTA GĀZU Emisiju SAMAZINĀŠANAS PERSPEKTĪVA Latvijas MĀJSAIMNIECĪBĀS

    Science.gov (United States)

    Kudrenickis, I.; Klavs, G.

    2013-12-01

    Utilisation of biomass is an important factor in reducing emission of greenhouse gases (GHG); at the same time, high efficiency of biomass combustion technologies is to be ensured to minimise the methane (CH4) emission thus achieving the most efficient reduction in the total GHG emission. The authors analyse the GHG emission breakdown in Latvia among the sectors not included in the EU Emissions Trading Scheme (ETS), and, in the context of emission reduction, evaluate the energy supply in the Latvian household sector, the types of combustion technologies and the used fuels. The trend is considered for the CH4 emission factor during 1990-2010 in the household sector of EU countries, and the numerical index is calculated which illustrates decoupling the consumption of biomass fuel from CH4 emission. To evaluate the perspective of CH4 emission reduction in the Latvian household sector, two scenarios are investigated for efficiency improvement as related to the central heating equipment based on wood fuel. Biomasas izmantošana ir viens no principiālajiem virzieniem siltumnīcefekta gāzu (SEG) emisiju samazināšanā. Maksimāla SEG emisiju samazinājuma panākšanai ir nepieciešams nodrošināt biomasas sadedzināšanas iekārtu augstu efektivitāti, lai minimizētu ar biomasas kurināmā patēriņu saistīto metāna (CH4) emisiju pieaugumu. Autori raksturo Eiropas Savienības (ES) Emisiju kvotu tirdzniecības sistēmas (ETS) un tajā neietilpstošo sektoru (ne-ETS) nozīmi Latvijas SEG emisiju veidošanā, SEG emisiju relatīvo sadalījumu atbilstoši dažādiem ne- ETS sektoriem un SEG emisiju samazināšanas kontekstā analizē Latvijas mājsaimniecību sektora energoapgādi, patērēto kurināmo un izmantotās kurināmā sadedzināšanas tehnoloģijas. Rakstā ir demonstrēta SEG emisiju inventarizācijā pielietotā CH4 emisiju specifiskā faktora mājsaimniecību sektora koksnes kurināmajam skaitlisko vērtību dinamika 1990-2010 gados dažādās ES valst

  13. PARTICIÓN DE LA BIOMASA AÉREA EN TRES ESPECIES ARBÓREAS TROPICALES

    OpenAIRE

    Martín Aquino-Ramírez; Alejandro Velázquez-Martínez; Juan F. Castellanos-Bolaños; Héctor De los Santos-Posadas; Jorge D. Etchevers-Barra

    2015-01-01

    El conocimiento de los almacenes de carbono en bosques es fundamental para generar inventarios de este elemento cercanos a la realidad. Para ello es necesario tener estimaciones de la biomasa de los árboles. Las ecuaciones alométricas permiten estimar la biomasa y su distribución en ecosistemas forestales. El objetivo del presente estudio fue desarrollar ecuaciones para estimar la biomasa aérea total y de los componentes estructurales, en árboles de la región fisiográfica de la Sierra M...

  14. Utjecaj alkohola na učinak u zadatku sljepoće zbog nepažnje u simuliranoj situaciji vožnje automobila

    Directory of Open Access Journals (Sweden)

    Andro Pavuna

    2012-05-01

    Full Text Available Akutna konzumacija etilnoga alkohola štetno utječe na brojne vidne funkcije. U ovom smo se istraživanju usredotočili na specifične procese vidne percepcije i pažnje te utjecaj relativno niskih razina alkohola na njih. U istraživanju je sudjelovalo 47 studenata raznih fakulteta Sveučilišta u Zagrebu. Sudionici u eksperimentalnoj skupini (N=22 konzumirali su alkoholni koktel stopostotnoga narančinog soka i votke kako bi dostigli ciljanu razinu alkohola u krvi od 0.8 g/kg, dok su sudionici u kontrolnoj skupini (N=25 konzumirali placebo – samo narančin sok sa snažnom aromom etilnoga alkohola. Nakon konzumacije pića sudionici su rješavali zadatak vidne percepcije i pažnje koji se sastojao od kratkoga video-isječka koji prikazuje režiranu realnu prometnu situaciju u kojoj jedno vozilo slijedi drugo s centralnim zadatkom brojanja paljenja ''štop'' svjetala na vozilu koje se kreće ispred njega, te percepcije značajnih objekata i detalja iz okoline poput dječjih kolica, djeteta koje prelazi cestu, prometnih zakova i sl. Provedenim je istraživanjem utvrđeno kako sudionici pod utjecajem alkohola postižu statistički značajno slabiji rezultat u zadatku vidne percepcije od sudionika koji nisu pod utjecajem alkohola. Dobiven je umjereni efekt u kumulativnom zadatku vidne percepcije i pažnje, te neznačajan, ali jasan trend štetnoga utjecaja alkohola na pojedine zadatke vidne percepcije i pažnje.

  15. Caracterização e quantificação dos processos erosivos de uma voçoroca na bacia do Riacho Manoel Félix no Complexo Metamórfico do Bação, Quadrilátero Ferrífero - MG.

    OpenAIRE

    Drumond, Flávio Nasser

    2015-01-01

    Programa de Pós-Graduação em Evolução Crustal e Recursos Naturais. Departamento de Geologia. Escola de Minas, Universidade Federal de Ouro Preto. Neste trabalho procurou-se compreender e quantificar os processos erosivos na bacia do riacho Manoel Felix, no distrito de São Gonçalo do Bação, em Itabirito (MG). Na região ocorre o gnaisse Funil, unidade pertencente ao Complexo Bação (Quadrilátero Ferrífero), que se encontra intensamente degradado pela erosão por voçorocas. Na bacia, com relevo...

  16. Predição da potência aeróbia (VO2máx de crianças e adolescentes em teste incremental na esteira rolante Prediction of aerobic power (VO2max of children and adolescents during an incremental treadmill test

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2013-03-01

    Full Text Available O consumo máximo de oxigênio (VO2máx é a quantidade máxima de energia que pode ser produzida pelo metabolismo aeróbio em determinada unidade de tempo, podendo ser determinado direta ou indiretamente através de equações preditivas. O objetivo deste trabalho foi elaborar uma equação preditiva específica para determinar o VO2máx de meninos de 10 a 16 anos. Quarenta e dois meninos realizaram teste ergoespirométrico de corrida em esteira rolante com velocidade inicial de 9 km/h até exaustão voluntária. Através da regressão linear múltipla foi possível desenvolver a seguinte equação para a determinação indireta do VO2máx: VO2máx (ml/min = -1574,06 + (141,38 x Vpico + (48,34 * Massa corporal, com erro padrão de estimativa = 191,5 ml/min (4,10 ml/kg/min e o coeficiente de determinação = 0,934. Sugerimos que esta é uma fórmula adequada para predizer o VO2máx para esta população.The maximal oxygen uptake (VO2max is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO2max: VO2max (ml/min = -1574.06 + (141.38 x Vpeak + (48.34 * Body mass, with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

  17. Calefaccion centralizada por biomasa, Cuéllar

    Directory of Open Access Journals (Sweden)

    Verdú Pérez, Jesús

    2001-10-01

    Full Text Available A plant of municipal central heating feeded with residual biomass, has been created in Cuéllar (Segovia, Spain, in order to demostrate its technical viability and to make more confortable the life of village inhabitants. Those residual biomass used as combustible, comes from the pine seeds, the key industry in the area. The calorific energy generated by combustion of those pine seeds, serves to heat the water to be send later through different pipes crossing the village. So, heating services and sanitary hot water are used according to the moment of the year. The study of the operative plant, allow us to discern the more adecuated operation parameters. reaching a total thermical yield of 60%. So its technical and economical viability concerning other traditional combustibles, its big environmental contribution to the production of energy, in addition to the social advantages -1ike the creation of new working jobs and the development of alternative activities in agricultura1 and forest areas- have contributed to present this plant as a model to be extended to other areas with potential biomass.Con el fin de demostrar su viabilidad técnica y económica y dar servicio a los habitantes de la localidad, se ha instalado en Cuéllar (Segovia, España, una planta de calefacción municipal alimentada con biomasa residual. Como combustible utiliza los residuos biomásicos procedentes de la industria piñonera de la zona. La energía calorífica generada por el proceso de combustión de éstos, calienta agua que es distribuida a través de un circuito de tuberías aisladas a través de la ciudad. Se proporcionan así los servicios de calefacción y agua caliente sanitaria según la época del año. El estudio de la operación de la planta, ha permitido caracterizar los parámetros de funcionamiento más adecuados. habiéndose obtenido un rendimiento térmico total de la instalación del 60%. quedando justificada su viabilidad técnica y econ

  18. LA BIOMASA DE LOS CULTIVOS EN EL AGROECOSISTEMA. SUS BENEFICIOS AGROECOLÓGICOS

    Directory of Open Access Journals (Sweden)

    Anirebis Martínez Romero

    2014-01-01

    Full Text Available La biomasa es el resultado de la transformación de la energía solar en energía química. El hombre a través de la historia la ha utilizado no solo para su alimentación sino también para la alimentación de sus animales. Los avances de la ciencia promovieron el desarrollo agrario basado en la revolución verde, la cual solo promueve la producción de alimentos ya sea de uso humano o animal, marginando la importancia de la biomasa como enriquecedor del recurso suelo al disponerse de los insumos necesarios para sustituir su fertilidad natural. En la actualidad la producción y conservación de la biomasa de cualquier cultivo cobra una importancia trascendente; porque ello contribuye, además, a la protección medioambiental a través de la captura de carbono. El presente trabajo tuvo como objetivo demostrar la importancia que proporciona la biomasa generalmente no alimenticia para los humanos, a fin de emplearla no solo como alimento animal, sino también como enriquecedora del recurso natural suelo. Las investigaciones realizadas en Cuba sobre el tema es pobre, aun cuando en la actualidad resulta de gran importancia encontrar variantes que permitan profundizar en la producción de biomasa en su relación con el medio ambiente. Finalmente se exponen los resultados preliminares sobre producción de biomasa a partir de la agrobiodiversidad presente en los escenarios productivos, a la vez que se reflexiona sobre la importancia del tema para futuras investigaciones.

  19. Implantación central de biomasa forestal y aprovechamiento de las masas forestales

    OpenAIRE

    Amengual Romaní, Carmen; Triguero Gil, Álvaro

    2013-01-01

    Se estudia la implantación de una central de biomasa en Cataluña, como alternativa energética renovable. Se trata de una instalación industrial diseñada para generar energía a partir de recursos biológicos. Aunque esta sea una tecnología en vías de desarrollo, las perspectivas de futuro son prometedoras. En la primera parte del proyecto, estudiaremos en profundidad el concepto de biomasa, incluyendo una recopilación de datos sobre los tipos que existen, las formas de conversión en energía,...

  20. Modelación cinética de pirólisis de biomasa

    OpenAIRE

    Monroy Peña, Camilo Antonio

    2013-01-01

    La pirolisis de biomasa es un proceso de conversión termoquímica de importancia industrial y ecológica. Por tanto se requiere encontrar un modelo cinético de pirolisis de biomasa que permita un adecuado modelamiento, diseño, optimización y operación de reactores industriales. En el presente trabajo se realizó un estudio de la descomposición térmica de cuesco de palma y de sus componentes separados vía enzimática, para no afectar las características estructurares y químicas de l...

  1. Shape controlled synthesis and tribological properties of CeVO4 nanoparticles as lubricating additive

    Institute of Scientific and Technical Information of China (English)

    LIU Fengzhen; SHAO Xin; YIN Yibin; ZHAO Limin; SHAO Zhuwei; LIU Xuehua; MENG Xianhua

    2011-01-01

    Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4· 12H2O and Ce(NO3)3·6H2O.The resulting products were characterized by X-ray powder diffraction (XRD),electron microscopy (SEM) and other techniques.On the basis of the experimental results,CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solution had an important effect on the crystal structure and morphology of CeVO4 nanoparticles.Furthermore,the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester.The results indicated that the wear resistance was improved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.

  2. MODELOS PREDICTIVOS DE BIOMASA AÉREA DE Eucalyptus grandis PARA EL NORESTE DE ARGENTINA

    Directory of Open Access Journals (Sweden)

    Rosa Angela Winck

    2015-01-01

    Full Text Available Diferentes intereses industriales, energéticos y ambientales han motivado el análisis de las distintas posibilidades de aprovechamiento de la biomasa forestal, este tema está adquiriendo un creciente protagonismo, por lo que la cuantificación de la biomasa aérea de estos sistemas forestales constituye un primer paso fundamental e ineludible. El objetivo de este trabajo fue desarrollar modelos que permitan estimar la biomasa de los diferentes compartimentos aéreos de Eucalyptus grandis . Para ello se emplearon datos de 41 árboles provenientes de rodales de diferentes edades, entre 4 y 32 años, ubicados en la región NE de Argentina. Se tomaron 23 individuos ubicados en la Zona Norte y Alta de Misiones (zona 1 y 18 en el Sur de Misiones y NE de Corrientes (zona 2. Se determinó la biomasa de hojas, ramas menores a 5 cm, ramas mayores a 5 cm, total de ramas, fuste y biomasa total del árbol. Para el ajuste de modelos se tomaron diversas variables independientes, el diámetro a la altura de pecho (dap, la altura total del árbol (h, el producto (dap 2 *h y la variable “ dummy” (zona. Para el caso de la biomasa de ramas y de hojas, debido a que no se lograron resultados satisfactorios con el empleo de estas variables, se examinaron modelos que adicionaban índice de sitio, factor de espaciamiento, diámetro en la base de la copa verde (dbcv, altura hasta la base de la copa verde (hbcv, longitud de copa verde (lcv, el área transversal de albura en la base de copa verde (g Alb bcv y diferentes combinaciones de estas variables. Los modelos fueron seleccionados en base al coeficiente de determinación y el error cuadrático medio. Para la biomasa de ramas menores a 5 cm, ramas mayores a 5 cm, total de ramas, fuste y total, los mejores modelos fueron los que incorporaron como variables regresoras, el diámetro a la altura de pecho, la altura total del árbol y la variable “ dummy” (zona. Para la biomasa de hojas, las variables, edad,

  3. Biomasa y densidad de dos especies de pastos marinos en el sur de Quintana Roo, México

    OpenAIRE

    2015-01-01

    La biomasa y productividad de una comunidad de pastos marinos es útil para determinar el estado ecológico de la costa. Se comparó la biomasa foliar y la densidad de vainas en praderas de Thalassia testudinum Banks & Sol. ex K. D . Koenig, en dos ambientes de la costa del Caribe mexicano eN= 6 cuadrantes/sitio) en Noviembre de 1998. Los valores de vainas y biomasa foliar fueron más bajos en la pradera asociada al manglar, que en la pradera establecida en una laguna arrecifal. Esto probablement...

  4. Inclusão do equivalente do lactato sanguíneo O2 na regressão de intensidade de exercício VO2 aumenta o gasto energético de corrida e diminui sua precisão

    Directory of Open Access Journals (Sweden)

    Victor Machado Reis

    2013-12-01

    Full Text Available INTRODUÇÃO E OBJETIVOS: Investigar se a inclusão do equivalente energético de lactato sanguíneo (LS em intensidades submáximas alteraria o gasto energético de corrida (Gc estimado para corrida supramáxima de alta intensidade assim como sua precisão MÉTODOS: O Gc foi determinado a partir da curva de regressão de velocidade do VO2. Para cada sujeito, uma regressão alternativa foi estabelecida em que energia equivalente a 3 ml de O2 kg-1∙mM-1 de LS foi adicionada ao VO2. Testes t pareados, correlações pareadas e plotagem de Bland-Altman foram utilizados para investigar se os dois métodos representam os mesmos fenômenos. RESULTADOS: Os principais achados foram que o Gc previsto para intensidades supramáximas incluídos entre 110 e 160% ao correspondente ao pico de VO2 dos indivíduos aumentou significativamente quando as medidas de LS foram incluídas nas regressões. A inclusão das medidas de LS também aumentaram a imprecisão do Gc a 110, 120, 130, 150 e 160%. CONCLUSÃO: Nossos resultados indicam que a inclusão do equivalente do lactato de O2 na regressão de intensidade de VO2-exercício aumenta o gasto energético e diminui sua precisão.

  5. Enfermedad pulmonar obstructiva crónica por exposición al humo de biomasa

    Directory of Open Access Journals (Sweden)

    Matías Lopez

    Full Text Available En este artículo se discute la relación existente entre la enfermedad pulmonar obstructiva crónica (EPOC y el humo de biomasa. Más de la mitad de la población utiliza biomasa como combustible principal, sobre todo en áreas rurales y en países en vías de desarrollo donde su uso llega hasta el 80%. La inhalación del humo de biomasa crea un estado inflamatorio crónico, que se acompaña de una activación de metaloproteinasas y una reducción de la movilidad mucociliar. Esto podría explicar la gran asociación existente entre la exposición a biomasa y EPOC, revelada por estudios observacionales y epidemiológicos provenientes de países en vías de desarrollo y de países desarrollados. En esta revisión exploramos también las diferencias entre la EPOC causada por tabaco y por biomasa, y encontramos que, a pesar de las diferencias fisiopatológicas, la mayoría de las características clínicas, calidad de vida y mortalidad fueron parecidas. En los últimos diez años se han realizado intervenciones para disminuir la exposición a biomasa mediante el uso de cocinas mejoradas y combustibles limpios, sin embargo, estas estrategias todavía no han sido exitosas debido a su incapacidad para reducir los niveles de contaminación a niveles recomendados por la Organización Mundial de la Salud, y por su falta de uso. Por lo tanto, hay una necesidad urgente de ensayos de campo aleatorios, cuidadosamente realizados, para determinar la verdadera gama de reducciones de contaminación potencialmente alcanzables, la probabilidad de su uso y los beneficios a largo plazo en la reducción de la gran carga mundial de EPOC

  6. Efecto de la concentración de linóculo y la melaza como suplemento de la vinaza de destilería para la producción de biomasa de Candida utilis nativa

    Directory of Open Access Journals (Sweden)

    Lady Cajo

    2011-01-01

    Full Text Available La vinaza es un residuo de las destilerías de alcohol, rico en materia orgánica y sales minerales, cuyo aprovechamiento está limitado y finalmente es vertido al alcantarillado, ocasionando contaminación, no obstante, puede constituir un sustrato par a la producción de biomasa de levaduras, utilizadas en la alimentación animal. En la presente investigación se determinó el efecto de la concentración del inóculo y la melaza como suplemento de la vinaza, para la producción de biomasa de Candida utilis nativa. Las levaduras se aislaron de panca de Zea mays L. “maíz” en agar Sabouraud glucosado, identificando el 40.23 % como C. utilis. Luego, se cultivaron en vinaza con 30 g/L de melaza, a 28 ºC, durante 24 horas, se pesó la biomasa y se seleccionó C. utilis MKJ12, debido a que alcanzó el mayor valor de 7.667 g/L. Esta levadura en concentraciones de 25, 50 y 75 mL/L de inóculo se cultivó en biorreactores tipo tanque, en lote discontinuo, conteniendo 300 mL de vinaza con 10, 30, y 50 g/L de melaza, con flujo de aire descendente (1vvm, y una incubación a 28 ºC, durante 20 horas. Con 50 mL/L de inóculo y 50 g/L de melaza se determinó el menor tiempo de generación (2.88 h y los mayores valores en el número de generaciones (6.95, tasa específica de crecimien to (0.35 h - 1 , peso de biomasa (11.78 g/L y proteína (40.15 %. Se demostró la factibilidad de la producción de biomasa de C. utilis con 5 mL/L de inóculo en vinaza suplementada con melaza.

  7. Modelos matemáticos y experimentales sobre el secado de biomasa

    Directory of Open Access Journals (Sweden)

    Jorge Armando Villalba Vidales

    2015-01-01

    Full Text Available El secado de biomasa como proceso previo a la combustión se ha convertido en la actualidad en un factor decisivo para mejorar la eficiencia de dichos procesos en los sectores industrial y residencial. Debido a la creciente importancia de este proceso, los investigadores han desarrollado una gran cantidad de modelos, tanto teóricos como experimentales, que buscan predecir la cinética de secado de diferentes tipos de biomasa. Si bien se han logrado grandes avances en el desarrollo de modelos, aún no existe un modelo unificado que permita predecir los perfiles de temperatura y humedad para diversos materiales. Dichas dificultades se generan fundamentalmente por la amplia diversidad de biomateriales y las grandes diferencias entre los procesos existentes. El propósito de este artículo es brindar una panorámica sobre el estado del arte relativo a modelos, tanto matemáticos como experimentales, utilizados en la actualidad para simular procesos de secado de la biomasa. Asimismo, proponer los elementos fundamentales que deberá poseer un modelo de secado unificado.

  8. VoIP Forensic Analyzer

    Directory of Open Access Journals (Sweden)

    M Mohemmed Sha

    2016-01-01

    Full Text Available People have been utilizing Voice over Internet Protocol (VoIP in most of the conventional communication facilities which has been of assistance in the enormous attenuation of operating costs, as well as the promotion of next- generation communication services-based IP. As an intimidating upshot, cyber criminals have correspondingly started interjecting the environment and creating new challenges for the law enforcement system in any Country. This paper presents an idea of a framework for the forensic analysis of the VoIP traffic over the network. This forensic activity includes spotting and scrutinizing the network patterns of VoIP-SIP stream, which is used to initiate a session for the communication, and regenerate the content from VoIP-RTP stream, which is employed to convey the data. Proposed network forensic investigation framework also accentuates on developing an efficient packet restructuring algorithm for tracing the depraved users involved in a conversation. Network forensics is the basis of proposed work, and performs packet level surveillance of VoIP followed by reconstruction of original malicious content or network session between users for their prosecution in the court.

  9. VOSA: A VO SED Analyzer

    Science.gov (United States)

    Rodrigo, C.; Bayo, A.; Solano, E.

    2017-03-01

    VOSA (VO Sed Analyzer, http://svo2.cab.inta-csic.es/theory/vosa) is a public web-tool developed by the Spanish Virtual Observatory (http://svo.cab.inta-csic.es/) and designed to help users to (1) build Spectral Energy Distributions (SEDs) combining private photometric measurements with data available in VO services, (2) obtain relevant properties of these objects (distance, extinction, etc) from VO catalogs, (3) analyze them comparing observed photometry with synthetic photometry from different collections of theoretical models or observational templates, using different techniques (chi-square minimization, Bayesian analysis) to estimate physical parameters of the observed objects (teff, logg, metallicity, stellar radius/distance ratio, infrared excess, etc), and use these results to (4) estimate masses and ages via interpolation of collections of isochrones and evolutionary tracks from the VO. In particular, VOSA offers the advantage of deriving physical parameters using all the available photometric information instead of a restricted subset of colors. The results can be downloaded in different formats or sent to other VO tools using SAMP. We have upgraded VOSA to provide access to Gaia photometry and give a homogeneous estimation of the physical parameters of thousands of objects at a time. This upgrade has required the implementation of a new computation paradigm, including a distributed environment, the capability of submitting and processing jobs in an asynchronous way, the use of parallelized computing to speed up processes (˜ ten times faster) and a new design of the web interface.

  10. EVALUACIÓN DEL CONTENIDO DE NUTRIENTES Y PRODUCCIÓN DE BIOMASA EN CEPAS DE LEVADURA COLOMBIANAS Y COMERCIALES EVALUATION OF THE NUTRIENT CONTENT AND BIOMASS PRODUCTION IN COLOMBIAN AND COMMERCIAL YEAST STRAINS

    Directory of Open Access Journals (Sweden)

    Nohora Patricia Manovacía Moreno

    2008-12-01

    Full Text Available En el presente estudio se evaluó la producción de biomasa, el contenido de algunos nutrientes (selenio, carbohidratos totales y proteína microbiana y el consumo de sustrato de cepas de levaduras comerciales y nativas pertenecientes al Banco de Germoplasma de la Nación Colombiana, manejado por la Corporación Colombiana de Investigación Agropecuaria, CORPOICA. Inicialmente se determinó el crecimiento de tres levaduras nativas seleccionadas al azar bajo diferentes condiciones de pH, temperatura y tiempo de fermentación usando un medio líquido de extracto de malta. Dentro de estas condiciones, las mejores respuestas se observaron a pH de 4,5, 25 °C y 24 horas de fermentación. Usando estas condiciones se evaluaron 100 accesiones de levaduras nativas y 4 comerciales por su producción de biomasa, contenido de selenio, carbohidratos totales y proteína microbiana y consumo de sustratos. De acuerdo con estas variables y un análisis de conglomerados fue posible agrupar las levaduras en grupos homogéneos. Hubo elevada variabilidad en la producción de biomasa entre las 104 cepas evaluadas, probablemente debido a la variabilidad biológica existente en la población estudiada. Los rendimientos de biomasa variaron entre 0,101 y 0,480 g de biomasa g-1 de azúcar consumido y las velocidades de producción de biomasa oscilaron entre 0,040 y 0,185 g L-1 h-1. El consumo promedio de nutrientes (g de nutrientes consumidos/ g de nutrientes disponibles fue de 91,6% en el caso de los carbohidratos y de 17,8% en el caso de la proteína. Se identificaron diez cepas de superior crecimiento y contenido de nutrientes, cuyo potencial prebiótico y probiótico será evaluado en futuros ensayos In vivo.In the present study biomass production and nutrient (selenium, total carbohydrate and microbial protein were evaluated in both commercial and native yeast isolates from the Colombian Germplasm Bank managed by the Colombian Corporation of Agricultural Research

  11. Efecto de nutrientes sobre la producción de biomasa del hongo medicinal Ganoderma lucidum

    Directory of Open Access Journals (Sweden)

    Ana María Torres López

    2011-04-01

    Full Text Available  Effect of nutrients in the biomass production of the medicinal mushroom Ganoderma lucidum Título corto: Efecto de nutrientes sobre la producción de G. lucidumResumen El hongo Ganoderma lucidum, en los constituyentes de su biomasa, tiene compuestos con propiedades benéficas para la salud; es por esto que el conocimiento de las condiciones nutricionales adecuadas para su crecimiento permitirá su producción industrial y a bajo costo. En este trabajo se evaluó a nivel de matraz el efecto de la relación C/N, y la presencia de diferentes fuentes de carbono, nitrógeno y micronutrientes sobre la producción de biomasa. Empleando glucosa y peptona como fuentes de carbono y nitrógeno, respectivamente, se encontró una relación C/N óptima de 16,7:1 para la cual la máxima producción de biomasa fue de 25 g/L. Manteniendo esta relación C/N, y sustituyendo la glucosa por lactosa o harina de cebada y la peptona por extracto de levadura, la producción de biomasa se incrementó a 35 g/L. En presencia de harina de cebada la adición al medio de cultivo de sales de Mg y K, y de tiamina, no generó un mayor incremento en la producción de biomasa. La producción de biomasa de G. lucidum se ve favorecida por la presencia en el medio de cultivo de relaciones C/N cercanas a las reportadas conforme a la composición típica de los hongos, así como por la presencia de sustratos complejos como la harina de cebada que le aportan además de la fuente de carbono micronutrientes necesarios para su desarrollo. Palabras clave: harina de cebada, relación C/N, micronutrientes, fuentes de carbono, fuentes de nitrógeno.  AbstractGanoderma lucidum fungus has some biomass components with beneficial health properties. The knowledge about its nutritionals requirements for growing will favor its industrial production at lower cost. In this work, the effect of C/N ratio, the presence of different carbon, nitrogen and micronutrients sources, on fungal biomass

  12. Cuantificación de ácidos grasos a partir de biomasa microalgal

    Directory of Open Access Journals (Sweden)

    García Sánchez, J. L.

    1993-12-01

    Full Text Available Long chain polyunsaturated fatty acids are focusing the interest of researchers as long as analytical techniques are being improved. The Lepage and Roy direct transesterification method is being widely used to measure fatty acid content of microalgae which are proposed as potential sources of these products. In this paper, the physical state of the biomass to be analyzed is studied. Comparison has been stated between lyophilized biomass and wet biomass just harvested. Furthermore, the amount of sample and the number of methyl ester extractions have also been studied. From the statistical analysis carried out, wet biomass to fatty acid determination and the adequate range of sample are proposed. Three methyl ester extractions improve the resolution of GC analysis.

    El interés creciente por los ácidos grasos poliinsaturados de cadena larga viene favorecido por la mejora de las técnicas de análisis. La metodología de transesterificación directa propuesta por Lepage y Roy está siendo ampliamente utilizada para la determinación del contenido en ácidos grasos de microalgas, consideradas como potenciales fuentes de estos productos. En el presente trabajo, se analiza la influencia del estado físico de la biomasa analizada, seca, normalmente por liofilización, o húmeda recién cosechada del cultivo. Asimismo, se analiza el efecto de la cantidad de biomasa empleada y del número de extracciones de los esteres metílicos obtenidos. Del estudio estadístico realizado se pone de manifiesto la importancia del estado físico de la muestra, aconsejándose el uso de biomasa directamente obtenida del cultivo. Se proponen los intervalos de cantidad de biomasa para metilación, así como la conveniencia de realizar tres extracciones previas a la inyección en el cromatógrafo, que favorece la resolución del análisis.

  13. La biomasa en la producción de electricidad en España

    Directory of Open Access Journals (Sweden)

    Espejo Marín, Cayetano

    2005-06-01

    Full Text Available The generation of electricity using biomass began in Spain in the mid-1990s. In this paper, we examine the combustible products used in the generation of this type of electricity, the legal framework protecting its production, the evolution of the installed power and its territorial distribution, the environmental impact of biomass as a renewable energy, the energy policy supporting this technology and the problems for the development of biomass as a energy source in Spain.

    [es] La producción de electricidad con biomasa comienza su desarrollo en España a mediados de los años noventa. En este artículo se analizan los productos combustibles de biomasa destinados a la generación de electricidad, el marco legal que protege esta producción, la evolución de la potencia instalada y su distribución territorial, el impacto ambiental de la biomasa como energía renovable, la política energética de apoyo a esta tecnología, y los problemas para el desarrollo de la biomasa como fuente energética en España. [fr] La biomasse dans la production d´électricité en Espagne. La production d'électricité avec biomasse commence son développement en Espagne vers le milieu des années quatre-vingt-dix. Dans cet article nous analysons les produits combustibles de biomasse destines à engendrer de l'électricité, le cadre légal qui protégé cette production, l'évolution de la puissance installée, la répercussion de l'environnement de la biomasse comme énergie renouvelable, la politique énergétique de soutien à cette technologie et les problèmes pour le développement de la biomasse comme source énergétique en Espagne.

  14. Valorización de Biomasa de origen vegetal mediante procesos térmicos y termoquímicos.

    OpenAIRE

    López González, Diego

    2013-01-01

    En particular, esta Tesis Doctoral tiene como objetivo la evaluación de los principales procesos de conversión termoquímica de biomasa, principalmente pirólisis, combustión y gasificación, mediante el sistema experimental de termobalanza acoplada a un espectrómetro de masas. Adicionalmente, se estudió la degradación de fluidos de intercambio de calor en su aplicación en plantas termosolares de concentración. Los procesos de conversión termoquímica de biomasa son los procesos más interesan...

  15. Reserva de carbono en biomasa forestal y suelos minerales en el Parque Nacional Malinche (México)

    OpenAIRE

    María Eugenia Valdez Pérez; Gandhi González Guerrero; Rafael Morales Ibarra; Rut Yadira Bolaños Suárez

    2016-01-01

    Las áreas naturales protegidas representan una de las estrategias para la mitigación del cambio climático. El objetivo de esta investigación consistió en estimar el contenido de carbono en biomasa forestal en suelos minerales y calcular las pérdidas de carbono por cambios de uso del suelo en el Parque Nacional Malinche (PNM). La superficie de bosque del PNM es de 17.496,34 ha y almacena 1.544.377,66 mg en bosque y 4.148.985,97 mg en suelos. Para estimar el contenido de biomasa forestal se apl...

  16. Avances en el modelado de la combustión de biomasa en spouted bed cónico

    OpenAIRE

    Saldarriaga Elorza, Juan Fernando

    2016-01-01

    290 p. En aras del desarrollo de un modelo riguroso para la combustión de biomasa vegetal en lecho en surtidor, en este Trabajo se ha avanzado en cuatro pilares fundamentales cuya implementación en el futuro permitirá desarrollar una herramienta que simule el comportamiento en la cámara de combustión de distintas formas de biomasa vegetal. Esta herramienta facilitará la labor de diseño de futuras plantas y permitirá evaluar y adaptar el funcionamiento de las mismas a cada alimentación, lo ...

  17. Hidrodinámica y Combustión de Biomasa Vegetal Residual en Spouted Bed Cónico

    OpenAIRE

    Achutegui Narbona, Aitor

    2014-01-01

    En este trabajo se ha analizado la fluidodinámica de diferentes biomasas en spouted bed ademas de la combustión de algunas de ellas. La fluidodínamica también se ha efectuado con diferentes dispositivos internos

  18. 不同晶型BiVO_4微球的制备及其对光催化性能的影响%Synthesis and photocatalytic activities of BiVO_4 microspheres with different crystalline forms

    Institute of Scientific and Technical Information of China (English)

    朱振峰; 杜娟; 李军奇; 张艳丽; 刘佃光; 于红光

    2011-01-01

    以Bi(NO3)3、NH4VO3为原料,NaOH为pH调节剂,采用微波水热法在180℃制备了BiVO4微球,分析了不同煅烧温度对晶型、形貌的影响,并进一步探讨了BiVO4晶型与其光催化性能的关系。采用XRD、SEM和UV-Vis吸收光谱对产品进行了分析表征,并以光催化降解亚甲基蓝为模型反应研究BiVO4的光催化性能。结果表明所制备的BiVO4微球是四方相结构,球的直径在1~3μm之间,将其在500℃煅烧后发生晶型转变,600℃煅烧可得到纯单斜相BiVO4微球,且具有良好的可见光催化活性。而且,不同晶型的BiVO4影响亚甲基蓝的降解效果。%Bismuth vanadate(BiVO4) microspheres were prepared with Bi(NO3)3 and NH4VO3 as starting materials and with NaOH to adjust pH through the microwave hydrothermal method at 180℃.The effect of different calcination temperatures on the crystalline phase and morphology was investigated,and the relationship between crystalline phase of BiVO4 and its photocatalytic performance was further studied.The as-prepared BiVO4 samples were characterized by XRD,SEM and UV-Vis.The photocatalytic activity of the BiVO4 microspheres was determined by degradation of methylene blue molecules under visible light irradiation.The results indicated that the crystalline phase of as-prepared BiVO4 microspheres was tetragonal phase,and the diameter of microspheres was 1-3μm.It is found that the phase transition had undergone after being calcined at 500℃,and monoclinic scheelite BiVO4 microspheres obtained by being calcined at 600℃ had the excellent visible-light photocatalysis.Besides,BiVO4 with different crystalline forms can affect the degradation of methylene blue molecules.

  19. Programación por metas Energía alternativa mediante biomasa.

    Directory of Open Access Journals (Sweden)

    Guerrero Casas, Flor María

    2003-01-01

    Full Text Available En este trabajo se presenta un modelo multicriterio de localización de centrales de generación de energía eléctrica mediante biomasa. Los objetivos considerados son: (1 minimizar el coste total de la operación, (2 maximizar la producción de electricidad obtenida, (3 maximizar la distancia entre plantas, (4 maximizar la aceptación social y (5 establecer las plantas o ampliaciones en aquellos lugares donde exista una mayor predisposición por parte de las administraciones locales. Finalmente, se concluye con una aplicación práctica mediante programación por metas ponderadas para la región andaluza, considerando los residuos procedentes del olivar como fuente de energía.

  20. COMPONENŢA AMINOACIZILOR DIN BIOMASA ALGEI CIANOFITE NOSTOC GELATINOSUM (SCHOUSB ELENK.

    Directory of Open Access Journals (Sweden)

    Sergiu DOBROJAN

    2016-02-01

    Full Text Available În articol este analizată componenţa aminoacizilor din biomasa algei cianofite Nostoc gelatinosum (Schousb Elenk. colectate de pe mediul nutritiv Drew. Din grupa aminoacizilor esenţiali în biomasa algei Nostoc gelatinosum (Schousb Elenk. se conţine în cantităţi majore leucina (2,142±0,06 mg/100 mg, treonina (1,188±0,02 mg/100 mg şi valina (1,085±0,03 mg/100 mg. Din aminoacizii neesenţiali predomină acidul aspartic (4,523±0,11 mg/100 mg şi acidul glutamic (2,774±0,07 mg/100 mg. Alga Nostoc gelatinosum (Schousb Elenk. are un conţinut bogat de aminoacizi şi poate servi ca sursă pentru vaste domenii de aplicare.THE AMINO ACIDS COMPOSITION OF THE BLUE-GREEN ALGANOSTOC GELATINOSUM (SCHOUSB ELENKThis article presents the amino acid content of the blue-green alga Nostoc gelatinosum (Schousb Elenk. collected from the Drew nutritive medium. From the essential amino group in Nostoc gelatinosum (Schousb Elenk. biomass, major amounts are contained leucine (2,142 ± 0,06 mg/100 mg, threonine (1,188 ± 0,02 mg/100 mg and valine (1,085 ± 0,03 mg/100 mg. From nonessential amino acids predominates aspartic acid (4,523 ± 0,11 mg/100 mg and glutamic acid (2,774 ± 0.07 mg/100 mg. The alga Nostoc gelatinosum (Schousb Elenk. has a high content of amino acids and can serve as a source for vast areas of application. 

  1. Securing VoIP keeping your VoIP network safe

    CERN Document Server

    (Bud) Bates, Regis J Jr

    2015-01-01

    Securing VoIP: Keeping Your VoIP Network Safe will show you how to take the initiative to prevent hackers from recording and exploiting your company's secrets. Drawing upon years of practical experience and using numerous examples and case studies, technology guru Bud Bates discusses the business realities that necessitate VoIP system security and the threats to VoIP over both wire and wireless networks. He also provides essential guidance on how to conduct system security audits and how to integrate your existing IT security plan with your VoIP system and security plans, helping you prevent

  2. Performance of VoIP on HSDPA

    DEFF Research Database (Denmark)

    Wang, Bang; Pedersen, Klaus I.; Kolding, Troels E.

    2005-01-01

    scheduler design incorporating VoIP packet aggregation and user multiplexing is proposed and the VoIP capacity is studied for a macro-cellular environment. Results are obtained for different delay budgets and packet scheduling settings, using either blind round robin or a slightly modified version...

  3. β-Nb9VO25

    Directory of Open Access Journals (Sweden)

    Rawia Nasri

    2014-05-01

    Full Text Available The title compound, nonaniobium vanadium pentacosaoxide, was prepared by a solid-state reaction at 1198 K. It is isotypic with Nb9AsO25, Nb9PO25 and Ta9VO25. The structure consists of NbO6 octahedra (one with 4/m.. and two with m.. symmetry and VO4 tetrahedra (-4.. symmetry sharing corners and edges to form a three-dimensional framework. This framework can be considered as a junction between ribbons made up from NbO6 octahedra and chains of NbO6 octahedra and chains of VO4 tetrahedra. The V site shows half-occupancy, hence one half of the VO4 tetrahedra is unoccupied. The structural differences with α-Nb9VO25, VOSO4, SbOPO4 and NbOPO4 oxides are discussed.

  4. Tunable VO2/Au hyperbolic metamaterial

    Science.gov (United States)

    Prayakarao, S.; Mendoza, B.; Devine, A.; Kyaw, C.; van Dover, R. B.; Liberman, V.; Noginov, M. A.

    2016-08-01

    Vanadium dioxide (VO2) is known to have a semiconductor-to-metal phase transition at ˜68 °C. Therefore, it can be used as a tunable component of an active metamaterial. The lamellar metamaterial studied in this work is composed of subwavelength VO2 and Au layers and is designed to undergo a temperature controlled transition from the optical hyperbolic phase to the metallic phase. VO2 films and VO2/Au lamellar metamaterial stacks have been fabricated and studied in electrical conductivity and optical (transmission and reflection) experiments. The observed temperature-dependent changes in the reflection and transmission spectra of the metamaterials and VO2 thin films are in a good qualitative agreement with theoretical predictions. The demonstrated optical hyperbolic-to-metallic phase transition is a unique physical phenomenon with the potential to enable advanced control of light-matter interactions.

  5. Security in VoIP

    Directory of Open Access Journals (Sweden)

    Floriana GEREA

    2012-04-01

    Full Text Available VoIP relies on packet switching, similar to the way that e-mails are sent over the Internet. The technology breaks down a voice call into bite-size information packets. Instead of keeping the switch open all the time, the information is sent and received as needed, allowing excess line capacity to be used to carry other data. When the voice data arrives at its destination, it's reassembled into a voice call. As voice over IP services grow in popularity, the potential for viruses, worms and other security threats aimed at the technology also will grow. The current paper's purpose is presenting several security solutions and applying them to integrated systems at an economical and social level.

  6. Creative MuVo2

    Institute of Scientific and Technical Information of China (English)

    zdwei

    2004-01-01

    苹果(Apple)与创新(Creative),这两大巨擘在MP3播放器上的造诣可谓各有千秋,前者推出的iPod系列在外形上独领风骚,而后者推出的NOMAND系列则在间效上无人能比。就在苹果最新型iPod3排山倒海般的宣传攻势下,创新也推出了一款以曼妙身材和相对低廉价格为主打的1.5GB硬盘式MP3播放器——NOMAND MuVo2。

  7. Biorefinery Technologies for Biomass Conversion Into Chemicals and Fuels Towards Zero Emissions (Review) / Nulles Emisiju Princips Biomasas Konversijas Tehnoloģijās Aizstājot Fosilos Resursus (Pārskata Raksts)

    Science.gov (United States)

    Gravitis, J.; Abolins, J.

    2013-10-01

    Exhausting of world resources, increasing pollution, and climate change are compelling the shift of the world economy from continuous growth to a kind of economy based on integration of technologies into zero emissions production systems. Transition from non-renewable fossil resources to renewable resources provided by solar radiation and the current processes in biosphere is seen in the bio-refinery approach - replacing crude oil refineries by biomass refineries. Biotechnology and nano-technologies are getting accepted as important players along with conventional biomass refinery technologies. Systems design is a significant element in the integration of bio-refinery technologies in clusters. A number of case-studies, steam explosion auto-hydrolysis (SEA) in particular, are reviewed to demonstrate conversion of biomass into value-added chemicals and fuels. Analysis of energy flows is made as part of modelling the SEA processes, the eMergy (energy memory) approach and sustainability indices being applied to assess environmental impacts. Resursu izsīkums, vides piesārņojums un globāla mēroga klimatiskās izmaiņas ir civilizācijas izdzīvošanai būtiski faktori, kas virza pasaules ekonomikas pārmaiņas, atsakoties no nepārtrauktas izaugsmes idejas par labu tādai ekonomikai, kas balstās uz atjaunojošamies resursiem un dažādu tehnoloģiju integrācijemisiju principam atbilstošās ražošanas sistēmās. Saules radiācijas ierosinātajos planētas biosfērā notiekošajos procesos radīto organisko vielu pārstrādes kompleksi, kas operē ievērojot sabalansētu nulles emisiju principu, tiek uzlūkoti kā tās ekonomiskās (ražošanas) struktūras, kurām jānodrošina pāreja uz atjaunojošos resursu izmantošanu, aizstājot esošās fosilo resursu (naftas, ogļu) pārstrādes rūpnīcas. Līdzās jau apgūtajām biomasas rafinēšanas tehnoloģijām svarīga un pieaugoša loma ekonomiskās sistēmas resursu bāzes nomaiņā ir bio- un nanotehnolo

  8. VO2 max in an Indian population: a study to understand the role of factors determining VO2 max.

    Science.gov (United States)

    Nitin, Y M; Sucharita, S; Madhura, M; Thomas, T; Sandhya, T A

    2013-01-01

    VO2 max is the maximum amount of oxygen a person can consume and the value does not change despite an increase in workload. There is lack of data evaluating the impact of factors, which could affect VO2 max measurement, particularly in Indian population. The objectives of the present study were (i) to estimate VO2 max in a young healthy Indian population and to compare it with available prediction equations for Indian population (ii) to correlate time to achieve VO2 max with the relative VO2 max (iii) to assess the factors affecting the time to achieve VO2 max measurement (body composition and physical activity level). Twenty healthy adult males (18-30 years) underwent detailed anthropometry, physical activity level and modified Bruce protocol for VO2 max assessment. Breath by breath VO2, VCO2, oxygen saturation, heart rate, blood pressure were measured continuously and following exercise protocol. There was an internal validity between the estimated VO2 max and the maximum heart rate (MHR) (r = 0.51, P VO2 max P VO2 max. Out of the 3 prediction equations computed to estimate VO2 max, 2 equations significantly overestimated VO2 max. In Conclusion, physical activity level emerged to be a strong predictor of time to VO2 max. Time to achieve VO2 max is an important factor to be considered when determining VO2 max. There was an overestimation in the VO2 max values derived from predicted equations.

  9. Comprehensive Comparison of VoIP SIP Protocol Problems and Cisco VoIP System

    Directory of Open Access Journals (Sweden)

    TALAL AL-KHAROBI

    2012-08-01

    Full Text Available Voice over IP (VoIP, use of the packet switched internet for telephony, has improved substantially in the past few years. On the other hand, VoIP has many challenges that do not exist in the public switched telephone network (PSTN, a circuit switched system. VoIP is an application running on the internet, and therefore inherits the internet’s security issues. It is important to realise that VoIP is a relatively young technology, and with any new technology, security typically improves with maturity. This paper provides a comprehensive comparison of a VoIP SIP protocol and CISCO VoIP system. The comparison involves the investigation of the vulnerabilities that target both systems and how secure each system is. With this comparison we present our conclusion on which system is more secure.

  10. VoLTE国际漫游方案分析%VoLTE Roaming Solution Analysis

    Institute of Scientific and Technical Information of China (English)

    张婷; 余骏华; 戴国华

    2016-01-01

    This paper introduced VoLTE roaming standard procedure and commercialization state. It compared LBO and S8HR roaming architecture and their speciifc requirements on mobile device. This paper also analyzed network selecting and registration procedure of mobile device while deploying VoLTE roaming. At last, it proposed commercializing VoLTE roaming solutions for service providers.%介绍了VoLTE国际漫游标准化进程以及运营商商用状况,对LBO和S8HR漫游架构进行对比分析,并研究不同漫游架构对移动终端的特殊要求以及终端Vo LT E漫游时的开机选网和注册流程,最后提出了运营商Vo LT E漫游商用建议。

  11. BIOSORCIÓN DE Cd, Pb y Zn POR BIOMASA PRETRATADA DE ALGAS ROJAS, CÁSCARA DE NARANJA Y TUNA

    Directory of Open Access Journals (Sweden)

    Lissette Vizcaíno Mendoza

    2015-01-01

    Full Text Available Debido a su movilidad en los ecosistemas y a su toxicidad para las formas superiores de vida,los metales pesados Cd, Pb y Zn son priorizados como unos de los contaminantes inorgánicosmás importantes debido al alto riesgo que representan para el medio ambiente. Con el objeto dedisminuir su concentración se diseñó un sistema para evaluar su remoción empleando biomasade algas rojas, cáscaras de naranja (Citrus sp. y tuna guajira (Opuntia sp.. Se estudió la influenciadel pretratamiento y el empaquetamiento mediante ensayos tipo batch, en los que se emplearonsoluciones de sodio y calcio. Se obtuvo como resultado una mayor capacidad de sorción de lasalgas modificadas con NaOH 0.1 N y de la naranja y la tuna con modificación sucesiva con NaOH yCaCl20.2 M, y una afección poco significativa (≤1% del proceso de sorción al empacar la biomasael placas planas de tul poliéster. La eficiencia de remoción se determinó mediante un reactor deflujo continuo de columna fija con un volumen líquido de 400 mL, 75 g de biomasa y tiemposde retención promedio de 1 y 2 h. Los resultados mostraron una eficiencia similar de las tresbiomasas para remover Cd y Pb, con promedios superiores al 95%, mientras que el Zn se removiócon mejor eficiencia (62% al emplear tuna modificada como sorbente. Finalmente, el materialse calcinó a 700 °C con lo que se obtuvo una ceniza estable frente a soluciones ácidas, lo cualgarantiza la captura de los metales removidos.

  12. VoIP挺进移动领域%VoIP Enters the Mobile Communication Field

    Institute of Scientific and Technical Information of China (English)

    王俊莲

    2006-01-01

    随着VoIP在全球的迅速发展,其对固定话音业务的侵蚀已经有目共睹.现在,VoIP已经不再局限于固定宽带领域,无线和移动领域成为VoIP的下一个目标市场.随着技术与终端等的逐渐成熟,VoIP对移动领域的威胁将日益明显.

  13. [VO2 max, a true exercise test].

    Science.gov (United States)

    Saunier, Carole

    2013-01-01

    VO2 max is nowadays an essential examination performed in the monitoring of heart failure. The nurse has a role to play during the test and in supporting the patient, although this test remains highly technical and complex.

  14. ESTUDIOS TOXICOLOGICOS COMO HERRAMIENTA PARA EVALUAR EL DESEMPENO DE UN REACTOR ANAEROBIO DE BIOMASA INMOVILIZADA

    Directory of Open Access Journals (Sweden)

    TATIANA RODRIGUEZ CHAPARRO

    2010-01-01

    Full Text Available Los efluentes de la Industria de Papel y Celulosa son usualmente tóxicos y mutagénicos. Esa característica se deriva principalmente por la presencia de compuestos xenobióticos formados durante el proceso. Los parámetros globales para el análisis de la calidad del agua como, demanda química de oxigeno, carbón orgánico total, entre otros, no permiten identificar si el potencial toxicológico es remediado después de los tratamientos. El objetivo de este trabajo fue evaluar el desempeño de un reactor anaerobio horizontal de biomasa inmovilizada (RAHBI tratando un efluente real de blanqueamiento de celulosa Kraft, por medio de ensayos de toxicidad (Daphnia similis Ceriodaphnia silvestrii , mutagenicidad y citotoxicidad (Allium cepa L. . Los resultados mostraron alta sensibilidad de todos los organismos estudiados y buena capacidad del reactor anaerobio para remover compuestos que ejercen efectos tóxicos y mutagénicos. Los bioensayos estudiados representan una alternativa interesante para el análisis de la calidad del agua y para la evaluación del desempeño de tratamientos.

  15. Obtención de etanol a partir de biomasa lignocelulósica

    Directory of Open Access Journals (Sweden)

    Mabel Viñals-Verde

    2012-01-01

    Full Text Available Se muestra el estado de la literatura en cuanto a la obtención de etanol a partir de hidrolizados lignocelulósicos, una alternativa muy estudiada en la actualidad en el mundo con vistas a disminuir el costo del etanol combustible. Se reportan los materiales lignocelulósicos que están en estudio siendo el bagazo de caña de azúcar y los derivados del maíz los más utilizados. Se presentan los métodos de pre-tratamiento, purificación del hidrolizado, fraccionamiento de la celulosa, obtención de microorganismos geneticamente modificados y producción a nivel de planta piloto e industrial. Los métodos de pretratamiento por explosión por vapor y de purificación por "overliming" son los más estudiados con resultados satisfactorios. Entre los métodos de fraccionamiento de la celulosa, la sacarificación y fermentación simultáneas (SSF se reporta como el proceso más novedoso y eficiente para la obtención de etanol a partir de biomasa aunque a nivel de planta piloto e industrial se continúa trabajando con el sistema de hidrólisis ácida. Se muestran algunos resultados obtenidos con microorganismos genéticamente modificados como la levadura Saccharomyces y la bacteria Escherichia coli.

  16. Perspectivas del potencial energético de la biomasa en el marco global y latinoamericano

    Directory of Open Access Journals (Sweden)

    Julián Rodrigo Quintero González

    2015-06-01

    Full Text Available El calentamiento global y los cambios climáticos que éste conlleva han fomentado desde hace algunos años la exploración de otros tipos de obtención energética para disminuir el uso del combustible fósil, siendo éste último uno de los principales causantes de dicho problema ambiental. El presente artículo expone algunas investigaciones recientes sobre la bioenergía u obtención de energía a partir de biomasa, considerada como energía limpia. Se abarcan temáticas como la bioenergía y sus posibilidades desde el punto de vista energético, teniendo en cuenta las expectativas de producción según su potencial o productividad energética, además del aporte que este tipo de tecnología hace a la disminución de la huella ecológica.

  17. LACK - a VoIP Steganographic Method

    CERN Document Server

    Mazurczyk, Wojciech

    2008-01-01

    The paper presents a new steganographic method called LACK (Lost Audio PaCKets Steganography) which is intended mainly for VoIP. The method is presented in a broader context of network steganography and of VoIP steganography in particular. The analytical results presented in the paper concern the influence of LACK's hidden data insertion procedure on the method's impact on quality of voice transmission and its resistance to steganalysis.

  18. 网络融合下的VoIP与IMS

    Institute of Scientific and Technical Information of China (English)

    叶华

    2007-01-01

    文章分析了VoIP的含义、分类,归纳总结了VoIP的网络能力,并在展望IMS发展趋势的基础上,提出了网络融合下IMS与VoIP的关系,认为IMS具备了VoIP成熟发展的网络条件,将会促进VoIP走向成熟阶段.

  19. Reações entre caolim, virus de influenza suína e inibidor de clara de ôvo da hemoaglutinação de vírus Reactions involving kaolin, swine influenza virus, and egg-whiteinhibidor of virus hemagglutination

    Directory of Open Access Journals (Sweden)

    Frank Lanni

    1952-03-01

    Full Text Available O caolim adsorve a atividade inibitória mais ràpidamente que o nitrogênio total da clara de ôvo bruta e menos ràpidamente que o nitrogênio total das preparações semipurificadas de inibidor. A adsorção do inibidor é reversível. O tratamento de preparações semipurificadas pelo vírus ativo da influenza suína causa um ligeiro aumento da adsorção da atividade e do nitrogênio total. O vírus ativo combina-se no frigorífico com o caolim que adsorveu o inibidor e pode ser em grande parte recuperado à temperatura ambiente. Uma quantidade menor de vírus é fixada pelo caolim não tratado. O aquecimento do vírus durante 30 minutos a 53°C aumenta sua adorção pelo caolim.Kaolin adsorbs inhibitory activity more rapidly than total nitrogen from crude egg-white and less rapidly than total nitrogen from semipurified inhibitor preparations. The adsorption of inhibitoris reversible. Treatment of semipurified preparations with active swine influenza virus causes a slight increase in the adsorption of activity and total nitrogen. Active virus combines with inhibitor-coated kaolin in the cold and can be recovered in great part at room temperature. A smaller amount of virus is bound by untreated kaolin. Heating the virus for 30 minutes at 53°C increases its adsortion by kaolin.

  20. Lattice relaxation and ferromagnetic character of (LaVO3)m/SrVO3superlattices

    Science.gov (United States)

    Schuster, Cosima; Lüders, Ulrike; Frésard, Raymond; Schwingenschlögl, Udo

    2013-08-01

    The experimental observation that vanadate superlattices (LaVO3)m/SrVO3 show ferromagnetism up to room temperature (Lüders U. et al., Phys. Rev. B, 80 (2009) 241102(R)) is investigated by means of density functional theory, and the band structure for m = 5 and 6 is calculated. A buckling of the interface VO2 layers is found in both cases, but subtle differences in bond length lead to very different properties for even and odd values of m: in the even case, the two interface VO2 layers effectively decouple from the adjacent LaO layers due to a strong bond length enhancement. This results into a local inversion of the orbital occupancy and to the confinement of the charge carriers. In the odd case, the amplitude of the bond length variation is smaller, so that the charge carriers spill into the deeper-lying VO2 layers, and spin-polarised interfaces are obtained.

  1. Vanadium dioxide - Reduced graphene oxide composite as cathode materials for rechargeable Li and Na batteries

    Science.gov (United States)

    Mahadi, Nurulhuda Binti; Park, Jae-Sang; Park, Jae-Ho; Chung, Kyung Yoon; Yi, Su Youl; Sun, Yang-Kook; Myung, Seung-Taek

    2016-09-01

    In this study, a metastable form of vanadium dioxide, denoted as VO2(B), has been successfully synthesized under solvothermal condition. However, the as-received VO2(B) suffers from fast capacity fading and poor high-rate performance. In order to overcome these problems, the as-received VO2(B) is solvothermally treated with reduced graphene oxide (rGO) to produce VO2(B)/rGO composite. As a result, the resulting electric conductivity of the VO2(B)/rGO composite is improved to ∼10-4 cm S-1 (from ∼10-7 S cm-1 for the as-received VO2(B)). Electrochemical data of the VO2(B)/rGO composite, tested in both Li and Na cells, shows markedly enhanced electrochemical performance compared to bare VO2(B). The effect of electro-conducting rGO is more evident at high rates.

  2. Effect of Preparation Parameters on Photoactivity of BiVO4 by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Qingyun Chen

    2012-01-01

    Full Text Available Bismuth vanadate (BiVO4 was synthesized from a mixture of aqueous Bi(NO33 and NH4VO3 solutions by using hydrothermal method. Via conducting the orthogonal experiments and single-factor experiments, the best synthetic parameters were determined. The physical and photophysical properties of the as-obtained samples were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and UV-Vis diffusion reflectance spectroscopy (UV-Vis. The result showed that the best experimental parameters of monoclinic BiVO4 were pH=7, T=195 °C, and    t=6 h. The catalytic performance of BiVO4 was evaluated by reducing carbon dioxide to methane under visible light irradiation. It was found that the methane production reached 145 μg/g-cat after 5 h irradiation with the catalyst dosage of 0.15 g in 200 mL mixed solution of 0.1 M NaOH and 0.1 M Na2SO3.

  3. Estudio de la logística de una planta de biomasa para abastecer de energía térmica a la Universidad de Valladolid.

    OpenAIRE

    González Iturralde, Ana

    2014-01-01

    El presente proyecto estudia el vector logístico de la instalación de una central térmica y una red de calor (District heating) utilizando una de las energías “verdes” que el Gobierno ha estado fomentando los últimos años: la biomasa. Esta planta, alimentada con distintos tipos de biomasa, va a dar servicio térmico a 31 edificios de la zona norte del municipio de Valladolid, pertenecientes tanto a la Universidad de Valladolid (UVa), al Ayuntamiento y a la Junta de Castilla y Le...

  4. Distribución de la biomasa y densidad de raíces finas en una gradiente sucesional de bosques en la Zona Norte de Costa Rica

    OpenAIRE

    Jiménez-Rodríguez, César; Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Forestal; Cartago, Costa Rica; Arias-Aguilar, Dagoberto; Instituto Tecnológico de Costa Rica, Escuela de Ingeniería Forestal; Cartago, Costa Rica

    2012-01-01

    En este estudio se evaluó la distribución de la biomasa radical, el índice de área radical (RAI) y la densidad longitudinal (RLD) de raíces finas (< 5 mm) en una gradiente sucesional de bosques húmedos tropicales en la zona de Florencia de San Carlos, Costa Rica. La variación de estos parámetros se evaluó en función de la profundidad del suelo y del estado sucesional.La biomasa radical, al igual que el RAI y el RLD, disminuyen conforme aumenta la profundidad en el perfil y coincide con los...

  5. Relaciones entre biomasa, tasa de crecimiento, respiración y respiración potencial en el crustáceo "Artemia salina"

    OpenAIRE

    Martínez, I. (Izaskun)

    2007-01-01

    Programa de Doctorado en Oceanografía [ES] El metabolismo respiratorio y la biomasa del zooplancton son parámetros clave para el entendimiento del flujo de energía, abundancia de la población, estructura de la comunidad, así como otras variables de comunidades planctónicas marinas. La actividad respiratoria del transporte de electrones del zooplancton (ETS) mide la respiración potencial (Ф) y es una aproximación para el consumo de oxígeno en la respiración y la biomasa. No e...

  6. Simulación en código Matlab de un reactor para la gasificación de biomasa en lecho fluidizado burbujeante

    OpenAIRE

    Tosina Fernández, Sergio

    2013-01-01

    Este proyecto simula un reactor unidimensional para la gasificación de biomasa supuesto en régimen estacionario, isotérmico y adiabático, con un esquema simplificado de reacciones, en el que se recogen la teoría hidrodinámica de las “Dos Fases” y distintas correlaciones y parámetros que proceden de ensayos y simulaciones de los últimos cincuenta años, aproximadamente. En los primeros capítulos del proyecto se sientan las bases y conceptos relacionados con la biomasa para una...

  7. Právo na život

    OpenAIRE

    DIVIŠOVÁ, Petra

    2011-01-01

    My baccalaureate work deals with the issue of right of life. From the very outset of the existence of mankind the human race has been concerned with the question of right over life and death and in the 21st century the mankind has not yet managed to solve this dilemma in a satisfying way. Right of life poses a basic human right which is the pre-requisition of all other values. The objective of this work has been to find out whether it represents a truly universal right or whether there are ex...

  8. Microstructure and thermochromic properties of VO{sub X}-WO{sub X}-VO{sub X} ceramic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Khamseh, S.; Ghahari, M. [Institute for Color Science and Technology, Department of Nanomaterial and Nanocoatings, Tehran (Iran, Islamic Republic of); Araghi, H. [Islamic Azad University, Department of Materials Engineering, Science and Research Branch, Tehran (Iran, Islamic Republic of); Faghihi Sani, M.A. [Sharif University of Technology, Department of Materials Science and Engineering, Tehran (Iran, Islamic Republic of)

    2016-03-15

    W-doped VO{sub 2} films have been synthesized via oxygen annealing of V-W-V (vanadium-tungsten-vanadium) multilayered films. The effects of middle layer's thickness of V-W-V multilayered film on structure and properties of VO{sub X}-WO{sub X}-VO{sub X} ceramic thin films were investigated. The as-deposited V-W-V multilayered film showed amorphous-like structure when mixed structure of VO{sub 2} (M) and VO{sub 2} (B) was formed in VO{sub X}-WO{sub X}-VO{sub X} ceramic thin films. Tungsten content of VO{sub X}-WO{sub X}-VO{sub X} ceramic thin films increased with increasing middle layer's thickness. With increasing middle layer's thickness, room temperature square resistance (R{sub sq}) of VO{sub X}-WO{sub X}-VO{sub X} ceramic thin films increased from 65 to 86 kΩ/sq. The VO{sub X}-WO{sub X}-VO{sub X} ceramic thin film with the thinnest middle layer showed significant SMT (semiconductor-metal transition) when SMT became negligible on increasing middle layer's thickness. (orig.)

  9. Generación eléctrica a partir de biomasa en una destilería diversificada

    Directory of Open Access Journals (Sweden)

    Pedro A. Rodríguez

    2007-01-01

    Full Text Available La instalación de una destilería de etanol diversificada, como una vía de generación de energía renovable integrada a la producción de alimentos, muestra relevantes ventajas en comparación con las destilerías tradicionales. En particular, para el caso de una planta de producción de etanol de este tipo, de 1200 hL/d, la generación de electricidad, con la biomasa que esta industria genera, alcanza el valor de 15,92 MW de potencia eléctrica excedente para el Sistema Electroenergético Nacional. Constituye un polo de desarrollo económico, social y estratégico, atendiendo al concepto de autosustentación dado por el Protocolo de Kyoto. El concepto de diversificación alcanza a todo el sector productivo. En las destilerías tradicionales la diversificación es incipiente. La biomasa constituye una de las principales fuentes de generación de energía limpia y barata, pasando de ser un subproducto, a un eslabón fundamental del proceso productivo.

  10. Reserva de carbono en biomasa forestal y suelos minerales en el Parque Nacional Malinche (México

    Directory of Open Access Journals (Sweden)

    María Eugenia Valdez Pérez

    2016-01-01

    Full Text Available Las áreas naturales protegidas representan una de las estrategias para la mitigación del cambio climático. El objetivo de esta investigación consistió en estimar el contenido de carbono en biomasa forestal en suelos minerales y calcular las pérdidas de carbono por cambios de uso del suelo en el Parque Nacional Malinche (PNM. La superficie de bosque del PNM es de 17.496,34 ha y almacena 1.544.377,66 mg en bosque y 4.148.985,97 mg en suelos. Para estimar el contenido de biomasa forestal se aplicaron ecuaciones alométricas y se trabajó con la cartografía del Instituto Nacional de Estadística y Geografía (INEGI en el análisis espacio-temporal de los cambios de uso de suelo. Para el carbono en suelos se aplicaron los valores del Panel Intergubernamental de Cambio Climático (IPCC.

  11. Effect of nonstoichiometry on Raman scattering of VO2 films

    Institute of Scientific and Technical Information of China (English)

    Yuan Hong-Tao; Feng Ke-Cheng; Wang Xue-Jin; Li Chao; He Chen-Juan; Nie Yu-Xin

    2004-01-01

    @@ We report on Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 films, compared with the stoichiometry VO2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO2 films is discussed.

  12. Caracterización química de biomasa y su relación con el poder calorífico

    OpenAIRE

    Álvarez Rodríguez, Ana

    2013-01-01

    Caracterización química, por el método tradicional de extracción, de 9 biomasas lignocelulósicas procedentes de cultivos de vid y olivo y estudio de su relación con el poder calorífico superior.

  13. Lessons Learned in Building VO Resources: Binding Together Several VO Standards into an Operational Service

    Science.gov (United States)

    Chilingarian, I.; Bonnarel, F.; Louys, M.; Le Sidaner, P.

    2012-09-01

    The International Virtual Observatory Alliance (IVOA) developed numerous interoperability standards during the last several years. Most of them are quite simple to implement from the technical point of view and even contain “SIMPLE” in the title. Does it mean that it is also simple to build a working VO resource using those standards? Yes and no. “Yes” because the standards are indeed simple, and “no” because usually one needs to implement a lot more than it was thought in the beginning of the project so the time management of the team becomes difficult. In our presentation we will start with a basic case of a simple spectral data collection. Then we will describe several examples of “small” technologically advanced VO resources built in CDS and VO-Paris and will show that many standards are hidden from managers' eyes at the initial stage of the project development. The projects will be: (1) the GalMer database providing access to the results of numerical simulations of galaxy interactions; (2) the full spectrum fitting service that allows one to extract internal kinematics and stellar populations from spectra of galaxies available in the VO. We conclude that: (a) with the existing set of IVOA standards one can already build very advanced VO-enabled archives and tools useful for scientists; (b) managers have to be very careful when estimating the project development timelines for VO-enabled resources.

  14. Influencia de la aplicación de vinaza en actividad y biomasa microbiana en un Entic Dystropept y un Fluventic haplustoll del Valle del Cauca, Colombia

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Montenegro Gómez

    2009-01-01

    Full Text Available Con la aplicación de vinaza, residuo de la producción de alcohol carburante a partir de la caña de azúcar, se evaluó el efecto sobre la actividad y biomasa microbiana del suelo y el suministro de K+ al cultivo de maíz dulce (Zea Mays en un Entic Dystropept y un Fluventic Haplustoll del Valle del Cauca, Colombia. Se utilizó un diseño completamente al azar con cuatro tratamientos y cinco repeticiones: T1 (100% requerimiento de K+ con KCl, T2 (100% requerimiento de K+ con vinaza, T3 (50% requerimiento de K+ con KCl +50% con vinaza y T4 (25% requerimiento de K+ con KCl +75% con vinaza. Se estimó biomasa microbiana por el método de fumigación-extracción. Se realizó análisis de varianza, prueba de comparación de medias, regresiones y correlaciones (SAS. Se presentaron diferencias significativas en la actividad y biomasa microbiana por época de muestreo y entre los diferentes muestreos; al final del cultivo el Entic Dystropept presentó el contenido más alto de biomasa microbiana-C en el T2, mientras que en el Fluventic Haplustoll fue en el T1. El menor qCO2 fue para el T2 del Entic Distropept y T1 del Fluventic Haplustoll, estos tratamientos presentaron mayor acumulación de biomasa en cada suelo respectivamente T2 (30 450 kg ha-1 y T1 (21 015.6 kg ha-1.

  15. Empleo de la relación residuo producto para la estimación de biomasa cañera potencial. Caso de estudio

    Directory of Open Access Journals (Sweden)

    Lizet Rodríguez-Machín

    2014-01-01

    Full Text Available El panorama energético de la biomasa va tomando un mayor auge ante el vaticinado agotamiento de los combustibles fósiles, el impacto ambiental que representa y la seguridad energética asociada. El presente trabajo se desarrolla en la Unidad Empresarial de Base (UEB Héctor Rodríguez. Esta unidad emplea el bagazo obtenido en el proceso industrial de producción de azúcar para la generación de calor y de electricidad sin estimar adecuadamente su potencial. El propósito de esta investigación es aplicar las ecuaciones matemáticas para la estimación de la biomasa herbácea potencial al caso de la biomasa cañera (bagazo y conocer su disponibilidad con fines energéticos. Se aplicó el método de evaluación con relación residuo producto (RRP, el valor calculado está dentro del rango de los reportados en la literatura, pero fue preciso emplear el RRP calculado para el país por ser este más representativo que el calculado para la UEB. Se estimó que la biomasa potencial en central azucarero entre 2007 y 2012 fue de 98 856 t de bagazo. El potencial bruto máximo fue de 3 222 MW-h/día, lo cual permite establecer el límite superior a alcanzar en cuanto a potencial de biomasa se refiere en el proceso industrial pero no tiene en cuenta la totalidad de la caña producida en el proceso agrícola.

  16. Variación anual de la biomasa de Nymphoides fallax Ornduff (Menyanthaceae en la Laguna de Tecocomulco, Hidalgo, México

    Directory of Open Access Journals (Sweden)

    Agustin Quiroz-Flores

    2015-07-01

    Full Text Available Durante un ciclo anual se cuantificó la variación en la estratifi cación vertical de la biomasa deNymphoides fallaxy se analizaron las variables físicas y químicas del agua y sedimentos de la laguna de Tecocomulco, Hidalgo. La producción anual neta de N. fallax fue de 3 070.1 g PS m2. En el mes de junio la biomasa alcanzó su máximo (958.4 g PS m2 . La contribución de biomasa foliar de N. fallax a la proporción total de biomasa representa el 10%, la de peciolos alcanza el 40% y la contribución de biomasa subterránea equivale en ocasiones a más del 50%. El nivel de fósforo en los sedimentos se encuentra por arriba de la cantidad necesaria para sostener la producción vegetal (= 0.04%. Por los resultados obtenidos en este estudio, se puede señalar que en aquellas zonas ribereñas de la laguna en donde los agricultores han construido bordos, se propicia que durante la época de lluvias la columna de agua cambie bruscamente sus dimensiones pasando de 10 cm hasta alcanzar los 75 cm de profundidad y se eleven los niveles de fósforo en agua y sedimentos, lo que a su vez induce queNymphoides fallaxse vea estresada, y en un caso extremo, temporalmente sea sustituida por aquellas especies mejor adaptadas a las nuevas condiciones físicas y químicas del medio.

  17. Euro-VO - Coordination of Virtual Observatory activities in Europe

    CERN Document Server

    Genova, Francoise; Arviset, Christophe; Lawrence, Andy; Pasian, Fabio; Solano, Enrique; Wambsganss, Joachim

    2015-01-01

    The European Virtual Observatory Euro-VO has been coordinating European VO activities through a series of projects co-funded by the European Commission over the last 15 years. The bulk of VO work in Europe is ensured by the national VO initiatives and those of intergovernmental agencies. VO activities at the European level coordinate the work in support of the three "pillars" of the Virtual Observatory: support to the scientific community, take-up by the data providers, and technological activities. Several Euro-VO projects have also provided direct support to selected developments and prototyping. This paper explains the methodology used by Euro-VO over the years. It summarizes the activities which were performed and their evolutions at different stages of the development of the VO, explains the Euro-VO role with respect to the international and national levels of VO activities, details the lessons learnt for best practices for the coordination of the VO building blocks, and the liaison with other European i...

  18. Factores del manejo para estabilizar la producción de biomasa con leguminosas en el trópico

    Directory of Open Access Journals (Sweden)

    T. E. Ruiz

    2006-01-01

    Full Text Available Este material tiene como objetivo abundar acerca de aquellos factores del manejo que conduzcan a estabilizar la producción de biomasa en sistemas ganaderos en el trópico. Es obvio que los sistemas mejorados y bien manejados de pasturas de gramíneas y leguminosas, en cualquiera de sus alternativas, son opciones para lograr la sostenibilidad. Una concepción más amplia y profunda es la relativa a los estudios de pasturas mixtas; éstos, deben tener un enfoque más biológico por lo que, además de considerar el ambiente en el cual se desarrollan y crecen, hay que incluir la forma en que los componentes vegetales se manifiestan en las especies implicadas del agroecosistema. Aquí no podemos olvidar el efecto del animal. Los problemas asociados con la persistencia se reconocen cada vez más como una preocupación real. Los diversos factores que controlan la permanencia de las especies forrajeras se agrupan en aquellos que pueden ser manejados y controlados por el productor, así como en los que éste no puede intervenir. Es por ello que las producciones animales y de otro tipo, derivados de estos sistemas, varían positivamente en el tiempo, en la medida en que se va consolidando la relación suelo /planta /animal. De esta correspondencia no puede quedar excluido el papel interactuante y modificador del hombre con los elementos antes señalados. La producción de biomasa es una actividad multidisciplinaria; de ahí que el éxito de su funcionamiento esté condicionado al conocimiento de las interacciones entre sus componentes, así como entre éstos y el medio ambiente, lo cual permitirá la generación de estrategias de manejo acordes con la ecología que conduzcan a mejorar la productividad y la sostenibilidad del agroecosistema. Por tanto, la producción de biomasa constituye un elemento determinante en el éxito y la eficiencia de los sistemas con leguminosas.

  19. Revisión sobre la corrosión de tubos sobrecalentadores en plantas de biomasa

    Directory of Open Access Journals (Sweden)

    Berlanga-Labari, C.

    2006-08-01

    Full Text Available The design of new biomass-fired power plants with increased steam temperature raises concerns of high-temperature corrosion. The high potassium and chlorine contents in many biomasses, specially in wheat straw, are potentially harmful elements with regard to corrosion. Chlorine may cause accelerated corrosion resulting in increased oxidation, metal wastage, internal attack, void formations, and loose non-adherent scales. The most severe corrosion problems in biomass-fired systems are expected to occur due to Cl-rich deposits formed on superheater tubes. In the first part of this revision the corrosion mechanism proposed are described in function of the conditions and compounds involved. The second part is focused on the behaviour of the materials tested so far in the boiler and in the laboratory. First the traditional commercial alloys are studied and secondly the new alloys and the coatings

    En el diseño de plantas de biomasa es muy importante tener en cuenta la temperatura del vapor para no tener problemas de corrosión. Esto, es debido al alto contenido de potasio y cloro que tienen la mayoría de los biocombustibles y, en especial, la paja de cereal. El objetivo de esta revisión es condensar el conocimiento actual sobre la corrosión de los sobrecalentadores a altas temperaturas provocada por compuestos clorados en plantas de biomasa. El cloro puede causar corrosión acelerada debido a la pérdida de metal del sobrecalentador, ataque interno y formación de capas de óxidos no adherentes. Los problemas de corrosión más severos en una caldera de biomasa se producen en los depósitos formados sobre los tubos sobrecalentadores. En la primera parte de esta revisión, se describen los mecanismos de corrosión propuestos en función de las condiciones de trabajo predominantes en la caldera. La segunda parte, se centra en revisar los estudios realizados para comprobar el comportamiento de los materiales mediante ensayos realizados en la

  20. 解密家用VoIP

    Institute of Scientific and Technical Information of China (English)

    陈荆花

    2006-01-01

    对一个计算机从业者,人们经常期望他了解所有VoIP技术——如同期望他能恢复硬盘、杀除病毒、组建家庭网络、让用不同语言写的程序兼容运行等等。而事实上,尽管一位计算机从业者可能读过许多行业杂志,或在实验室研究过Asterisk(开放源代码的软件VoIP PBX系统)和SIP网关之类的东西,但真正要在家庭动手实践时,那些理论不一定能解决问题。

  1. Simulink based VoIP Analysis

    CERN Document Server

    Singh, Hardeep; Mian, M

    2010-01-01

    Voice communication over internet not be possible without a reliable data network, this was first available when distributed network topologies were used in conjunction with data packets. Early network used single centre node network in which a single workstation (Server) is responsible for the communication. This posed problems as if there was a fault with the centre node, (workstation) nothing would work. This problem was solved by the distributed system in which reliability increases by spreading the load between many nodes. The idea of packet switching & distributed network were combined, this combination were increased reliability, speed & responsible for voice communication over internet, Voice-over-IP (VoIP)These data packets travel through a packet-switched network such as the Internet and arrive at their destination where they are decompressed using a compatible Codec (audio coder/decoder) and converted back to analogue audio. This paper deals with the Simulink architecture for VoIP network.

  2. Steganography of VoIP streams

    CERN Document Server

    Mazurczyk, Wojciech

    2008-01-01

    In this paper, we circumscribe available steganographic techniques that can be used for creating covert channels for VoIP (Voice over Internet Protocol) streams. Apart from characterizing existing steganographic methods we provide new insights by presenting two new techniques. First one is network steganography solution and exploits free/unused fields of the RTCP (Real-Time Control Protocol) and RTP (Real-Time Transport Protocol) protocols. The second method provides hybrid storage-timing covert channel by utilizing delayed audio packets. The results of the experiment, that was performed, regardless of steganalysis, to estimate a total amount of data that can be covertly transferred in VoIP RTP stream during the typical call, are also included in this article.

  3. Gallinaza: Un residual avícola como fuente alternativa de nutrientes para producción de biomasa microalgal

    Directory of Open Access Journals (Sweden)

    Rosales Loaiza Nestor Luis

    2007-07-01

    Full Text Available La gallinaza puede ser usada como una fuente alternativa de nutrientes para el cultivo de microalgas, proveyendo de biomasa microalgal utilizable como producto final. El objetivo de este trabajo fue evaluar el efecto de la fracción soluble de gallinaza (FSG a tres diferentes concentraciones (6, 18 y 36% sobre el crecimiento, la producción de pigmentos y proteínas de la microalga marina Chroomonas sp. y de la microalga de agua dulce Chlorella sorokiniana. La FSG no biodegradada mostró un efecto letal sobre el crecimiento de ambas microalgas. La FSG tratada aeróbicamente mejoró el crecimiento de Chroomonas sp. a 18% con 131,37 ±13,66 x106 cel mL-1, y a 36% para C. sorokiniana de 228,64 ±4,90 x106 cel mL-1 (p

  4. IMPLEMENTACION DE PROCESOS DE CO-COMBUSTION DE CARBON Y BIOMASA EN CHILE: ESTUDIO DE FACTIBILIDAD TECNICA Y ECONOMICA

    OpenAIRE

    GARCIA CARMONA, XIMENA ANDREA

    2009-01-01

    Se ha estudiado la co-combustión de carbón con biomasa como alternativa para la generación de electricidad en Chile. El trabajo fue abordado desde dos ámbitos: a) el del diagnóstico, estudio y análisis (fase analítica) y b) el ámbito de la experimentación (fase tecnológica). Como resultados del primer enfoque, se presentan los estudios realizados, que incluyen una prospección completa de la situación actual chilena en cuanto a termogeneración eléctrica a partir de carbón. A partir...

  5. Valorización energética de la biomasa : aplicación en industrias del sector agroalimentario

    OpenAIRE

    García Morales, José Luis; Romero, L. I.; Sales, D.

    2008-01-01

    La utilización de la biomasa proveniente del sector agroalimentario como una fuente de energía renovable es de gran interés en la actualidad. Ésta puede generar energía, a través de procesos tanto termoquímicos como bioquímicos, susceptible de utilizarse en forma de calor, energía mecánica o electricidad, y en diferentes estados de agregación: sólida, líquida o gas. La Digestión Anaerobia de vertidos de destilerías vínicas es un ejemplo idóneo de los procesos bioquímicos de conversión de l...

  6. Lattice relaxation and ferromagnetic character of (LaVO3) m/SrVO3superlattices

    KAUST Repository

    Schuster, Cosima B.

    2013-08-01

    The experimental observation that vanadate superlattices (LaVO 3)m/SrVO3 show ferromagnetism up to room temperature (Lüders U. et al., Phys. Rev. B, 80 (2009) 241102(R)) is investigated by means of density functional theory, and the band structure for m = 5 and 6 is calculated. A buckling of the interface VO2 layers is found in both cases, but subtle differences in bond length lead to very different properties for even and odd values of m: in the even case, the two interface VO2 layers effectively decouple from the adjacent LaO layers due to a strong bond length enhancement. This results into a local inversion of the orbital occupancy and to the confinement of the charge carriers. In the odd case, the amplitude of the bond length variation is smaller, so that the charge carriers spill into the deeper-lying VO2 layers, and spin-polarised interfaces are obtained. © Copyright EPLA, 2013.

  7. What are suspicious VoIP delays?

    CERN Document Server

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    2010-01-01

    Voice over IP (VoIP) is unquestionably the most popular real-time service in IP networks today. Recent studies have shown that it is also a suitable carrier for information hiding. Hidden communication may pose security concerns as it can lead to confidential information leakage. In VoIP, RTP (Real-time Transport Protocol) in particular, which provides the means for the successful transport of voice packets through IP networks, is suitable for steganographic purposes. It is characterised by a high packet rate compared to other protocols used in IP telephony, resulting in a potentially high steganographic bandwidth. The modification of an RTP packet stream provides many opportunities for hidden communication as the packets may be delayed, reordered or intentionally lost. In this paper, to enable the detection of steganographic exchanges in VoIP, we examined real RTP traffic traces to answer the questions, what do the "normal" delays in RTP packet streams look like? and, is it possible to detect the use of know...

  8. Facile synthesis and high activity of novel BiVO{sub 4}/FeVO{sub 4} heterojunction photocatalyst for degradation of metronidazole

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jinhai [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); School of Chemical Engineering, Guizhou University of Engineering Science, Bijie 551700 (China); Zhao, Wei; Guo, Yang; Wei, Zhongbo; Han, Mengshu [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); He, Huan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); School of Public Health, University of Illinois at Chicago, Chicago, IL 60631 (United States); Yang, Shaogui [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824 (United States); Sun, Cheng, E-mail: envidean@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China)

    2015-10-01

    Graphical abstract: - Highlights: • BiVO{sub 4}/FeVO{sub 4} was synthesized by a facile one-step hydrothermal method. • BiVO{sub 4}/FeVO{sub 4} displays superior photocatalytic activity. • The photocatalytic mechanism were discussed in detail. - Abstract: The novel BiVO{sub 4}/FeVO{sub 4} heterojunction photocatalyst was successfully synthesized by a facile hydrothermal method firstly. The physical and chemical properties of as-prepared samples were characterized based upon XRD, XPS, BET, SEM, EDS, TEM, UV–vis DRS and fluorescence spectrum techniques. The TEM images showed a clear interface between BiVO{sub 4} and FeVO{sub 4}, indicating that a heterojunction between BiVO{sub 4} and FeVO{sub 4} was formed during the hydrothermal reaction. In addition, the photodegradation activity of metronidazole (MNZ) was used as a measurement for photocatalytic performance of BiVO{sub 4}, FeVO{sub 4} and BiVO{sub 4}/FeVO{sub 4} heterojunction photocatalyst. It indicated that under visible light irradiation the photocatalytic activity of BiVO{sub 4}/FeVO{sub 4} heterojunction photocatalyst was very effective, and moreover, much higher than the single BiVO{sub 4} or single FeVO{sub 4}. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation of the electronic structure, and the experimental results.

  9. A novel inorganic precipitation-peptization method for VO2 sol and VO2 nanoparticles preparation: Synthesis, characterization and mechanism.

    Science.gov (United States)

    Li, Yao; Jiang, Peng; Xiang, Wei; Ran, Fanyong; Cao, Wenbin

    2016-01-15

    In this paper, a simple, safe and cost-saving precipitation-peptization method was proposed to prepare VO2 sol by using inorganic VOSO4-NH3⋅H2O-H2O2 reactants system in air under room temperature. In this process, VOSO4 was firstly precipitated to form VO(OH)2, then monometallic species of VO(O2)(OH)(-) were formed through the coordination between VO(OH)2 and H2O2. The rearrangement of VO(O2)(OH)(-) in a nonplanar pattern and intermolecular condensation reactions result in multinuclear species. Finally, VO2 sol is prepared through the condensation reactions between the multinuclear species. After drying the obtained sol at 40°C, VO2 xerogel exhibiting monoclinic crystal structure with the space group of C2/m was prepared. The crystal structure of VO2 nanoparticles was transferred to monoclinic crystal structure with the space group of P21/c (VO2(M)) by annealing the xerogel at 550°C. Both XRD and TEM analysis indicated that the nanoparticles possess good crystallinity with crystallite size of 34.5nm as estimated by Scherrer's method. These results suggest that the VO2 sol has been prepared successfully through the proposed simple method.

  10. UPORABA TEHNOLOGIJE VOIP NA MOBILNIH NAPRAVAH SYMBIAN

    OpenAIRE

    Uršič, Tine

    2013-01-01

    V sklopu diplomskega dela smo razvili aplikacijo, katere cilj je nižanje stroškov klicev s pomočjo tehnologije VoIP. Ta za komunikacijo uporablja protokol IP in zaobide potrebo po navadnih in dražjih GSM klicih. V času načrtovanja aplikacije je bilo okolje Symbian najbolj razširjena mobilna platforma za dovolj zmogljive, t.i. »pametne telefone«, ki lahko poganjajo VoIP aplikacije. Izbrali smo skupek knjižnic, poimenovanih Qt, ki omogočajo enostavno prenosljivost na druge platforme. Podr...

  11. Validade preditiva da medida e estimativas do VO2máx no desempenho de Mountain Bikers

    Directory of Open Access Journals (Sweden)

    Fernanda Mainardi

    2015-02-01

    Full Text Available INTRODUÇÃO: considerando o racional para a utilização das equações preditivas na estimativa do VO2máxem atletas, nenhum estudo estabeleceu sua validade para o desempenho no mountain bike cross-country(XCO.OBJETIVO: comparar diferentes estratégias de determinação do VO2máx, de forma direta ou indireta, para a predição do desempenho em uma prova real e outra simulada.MÉTODOS: 20 atletas de XCO do sexo masculino (31,6 ± 6,8 anos; 68,1 ± 6,5 kg; 175,5 ± 5,7cm; 64,9 ± 4,4 mL. kg-1.min-1, foram submetidos a três sessões experimentais. A primeira visita consistiu na estratificação de risco, avaliação antropométrica e teste progressivo máximo. Na segunda, foi realizada a prova simulada e, na terceira, foi realizada a competição de XCO.RESULTADOS: a correlação entre a prova simulada e as equações preditivas do VO2máx de forma absoluta alcançaram relação quase perfeita (r ≥ 0,9. As correlações entre a competição real e as estimativas de VO2máx relativizadas à massa corporal alcançaram resultados classificados como muito altos (r = 0,7-0,89. As associações entre a medida direta do VO2máx e a simulação apresentaram uma classificação baixa para valores relativos à massa corporal (r = 0,10, IC95%-0,35 a 0,51. Para o desempenho real, a classificação foi moderada (r = 0,48, IC95% 0,009 a 0,78.CONCLUSÃO: o presente estudo foi o primeiro a demonstrar a validade preditiva das estimativas do VO2máx para o desempenho simulado e real de MTB. Em complemento, confirmou a baixa validade preditiva da medida direta do VO2máx para o mesmo propósito.

  12. PyVO: Python access to the Virtual Observatory

    Science.gov (United States)

    Graham, Matthew; Plante, Ray; Tody, Doug; Fitzpatrick, Mike

    2014-02-01

    PyVO provides access to remote data and services of the Virtual observatory (VO) using Python. It allows archive searches for data of a particular type or related to a particular topic and query submissions to obtain data to a particular archive to download selected data products. PyVO supports querying the VAO registry; simple data access services (DAL) to access images (SIA), source catalog records (Cone Search), spectra (SSA), and spectral line emission/absorption data (SLAP); and object name resolution (for converting names of objects in the sky into positions). PyVO requires both AstroPy and NumPy.

  13. Determinación de la biomasa en procesos biológicos.II Métodos aplicados al tratamiento biológico de aguas residuales

    OpenAIRE

    Arnáiz Franco, Carmen; Isac Oria, Laura; Lebrato Martínez, Julián

    2000-01-01

    Artículo original escaneado para el Repositorio (archivo delegado) La concentración y la actividad de la biomasa son dos parámetros de gran importancia para el diseño y control de los procesos biológicos. En la depuración biológica de aguas residuales, la determinación del peso seco es una medida muy usada para la caracterización de la biomasa. Sin embargo, este parámetro no es suficiente para describir la actividad bilológica. Son necesarios, por tanto, otros métodos analíticos para una m...

  14. Identificación del mecanismo de solvatación de biomasa lignocelulósica con líquidos iónicos

    OpenAIRE

    Acosta Zamora, Edison Andres

    2014-01-01

    Se realizo un estudio sobre la reacción de solvatación y recuperación de polímeros estructurales de biomasa lignocelulósica con líquido iónico cloruro de 1-butil-3 metil-imidazolio. Se utilizo raquis de plátano como biomasa, la cual fue caracterizada mediante protocolos NREL y mediante un diseño factorial se evalúo los factores más influyentes del proceso y las mejores condiciones de temperatura, tiempo de reacción y carga de sólidos para la recuperación de celulosa, hemicelulosa y lignina, l...

  15. Optimización mediante técnicas de teoría gris de la combustión de biomasa en un drop furnace

    OpenAIRE

    Arce Fariña, Maria Elena

    2013-01-01

    El creciente desarrollo que ha experimentado el mercado de la biomasa conlleva que la investigación (I+D) se enfoque en la selección de las condiciones óptimas de combustión de los biocombustibles. La complejidad del proceso de combustión de biomasa, en el que existen parámetros divergentes, hace necesario el uso de métodos de análisis avanzados. Así, en esta investigación se propone un nuevo método multi-objetivo de selección de condiciones óptimas de combustión, basado en la combinación del...

  16. 基于SIP的VoIP安全问题研究%Research of VoIP Security Based on SIP

    Institute of Scientific and Technical Information of China (English)

    洪亮

    2013-01-01

    当前,基于SIP的VoIP运用越来越广泛.本文介绍了基于SIP协议的VoIP工作原理,重点分析了基于SIP协议的VoIP所面临的安全威胁,并对可用于SIP协议的各种安全机制进行了研究.

  17. La掺杂BiVO4微米球的水热合成和光催化性能%Hydrothermal synthesis and photocatalytic properties of La­doped BiVO4 microspheres

    Institute of Scientific and Technical Information of China (English)

    刘国聪; 金真; 张喜斌; 李险峰; 刘鸿

    2013-01-01

    Using Bi(NO3)3∙5H2O, NaVO3 and La(NO3)3∙5H2O as raw materials, La­doped BiVO4 microspheres were characterized and analyzed by hydrothermal process with glucose as the template. The as­prepared samples were investigated by XRD, XPS, SEM, FTIR, UV­Vis, BET and photocatalysis techniques. The results reveal that uniform, well crystallized and microspherical La/BiVO4 monoclinic crystal with the diameter range of 2−9 µm, which is self­assembled by lots of nanoparticles with the size of 30−65 nm, can be obtained via a hydrothermal route assisted by 2.0 g glucose. Compared with BiVO4 irregular particles, La/BiVO4 microspheres show a little red shift in the absorption band, resulting in a narrowed band gap (<2.4 eV). For 2.0%La/BiVO4 (mass fraction) microspheres, its photodegradation rate constant k is 5.63×10−2 min−1 and the best photocatalytic activity is found with a 100% degradation of methylene blue (MB) with a concentration of 10 mg/L under visible­light irradiation for 60 min.%  以Bi(NO3)3∙5H2O、NaVO3和La(NO3)3∙5H2O为原料,以葡萄糖为结构导向剂,通过水热法制备La掺杂BiVO4微米球。采用XRD、XPS、SEM、FTIR、UV­Vis、BET、光催化技术等对产品进行了表征和分析。结果表明,采用葡萄糖(2.0 g)辅助水热法能合成结晶度高且形貌规整的单斜白钨矿La/BiVO4微米球,微米球直径范围为2~9µm,均由尺寸为30~65 nm纳米颗粒自组装而成。相比BiVO4块状颗粒,球状La/BiVO4的紫外−可见光吸收边发生了稍许红移,具有较小的能带隙(<2.4 eV),其中,2.0%La/BiVO4(质量分数)微米球表现出最高的光催化活性,其速度常数k为5.63×10−2 min−1,可见光照射10 mg/L亚甲基蓝溶液60 min时的光解率达100%。

  18. Study of Thermal properties of VO2 and multilayer VO2 thin films for application in Thermal Switches

    Science.gov (United States)

    Zhu, Gaohua

    Ultrafast nature of the phase transition near room temperature in VO2 makes it attractive material for applications in electronics and optical devices however utilization of corresponding drastic change in thermo-physical properties are rarely reported. In this study we investigate thermal and electronic properties of VO2 thin films on various substrates across the transition temperature to seek possibility of utilizing VO2 based thermal switches for applications in thermal devices. In addition, the interfacial heat transfer in VO2/metal multilayer thin film is mediated by phonons at low temperature, and when temperature is elevated beyond phase transition temperature, the interface thermal conductance is mediated mainly by both phons and electrons. VO2-multilayers approach is studied to utilize the switching interface thermal conductance in order to obtain higher thermal conductivity switch ratio than what can be achieved in intrinsic VO2. Thermal conductivities and interface thermal conductance of VO2 and VO2 multilayer thin films are measured using the time-domain thermoreflectance (TDTR) method. We will discuss interplay of phononic and electronic component to thermal conductivity in the light of Wiedemann-Franz law across the metal to insulator state of VO2 films.

  19. BiVO(4)/CuWO(4) heterojunction photoanodes for efficient solar driven water oxidation.

    Science.gov (United States)

    Pilli, Satyananda Kishore; Deutsch, Todd G; Furtak, Thomas E; Brown, Logan D; Turner, John A; Herring, Andrew M

    2013-03-07

    BiVO(4)/CuWO(4) heterojunction electrodes were prepared using spray deposition of a highly porous bismuth vanadate film onto the surface of an electrodeposited three dimensional network connected copper tungstate. Bilayer BiVO(4)/CuWO(4)/fluorine doped tin oxide glass (FTO) electrodes demonstrated higher photocurrent magnitudes than either with BiVO(4)/FTO or CuWO(4)/FTO electrodes in 1.0 M Na(2)SO(4) electrolyte buffered at pH 7. The photocurrent is enhanced by the formation of the heterojunction that aids charge carrier collection brought about by the band edge offsets. When the pH 7 buffered electrolytes contained 1.0 M bicarbonate is employed instead of 1.0 M sulfate, the charge transfer resistance was decreased. This led to nearly 1.8 times the photocurrent density at 1.0 V vs. Ag/AgCl. The photocurrent was stable over 24 hours in bicarbonate electrolyte.

  20. Blind source computer device identification from recorded VoIP calls for forensic investigation.

    Science.gov (United States)

    Jahanirad, Mehdi; Anuar, Nor Badrul; Wahab, Ainuddin Wahid Abdul

    2017-03-01

    The VoIP services provide fertile ground for criminal activity, thus identifying the transmitting computer devices from recorded VoIP call may help the forensic investigator to reveal useful information. It also proves the authenticity of the call recording submitted to the court as evidence. This paper extended the previous study on the use of recorded VoIP call for blind source computer device identification. Although initial results were promising but theoretical reasoning for this is yet to be found. The study suggested computing entropy of mel-frequency cepstrum coefficients (entropy-MFCC) from near-silent segments as an intrinsic feature set that captures the device response function due to the tolerances in the electronic components of individual computer devices. By applying the supervised learning techniques of naïve Bayesian, linear logistic regression, neural networks and support vector machines to the entropy-MFCC features, state-of-the-art identification accuracy of near 99.9% has been achieved on different sets of computer devices for both call recording and microphone recording scenarios. Furthermore, unsupervised learning techniques, including simple k-means, expectation-maximization and density-based spatial clustering of applications with noise (DBSCAN) provided promising results for call recording dataset by assigning the majority of instances to their correct clusters.

  1. VoIP makes voice heard--functionality is up.

    Science.gov (United States)

    Wade, Phil; Wakelam, Mathew

    2008-05-01

    Phil Wade, sales and marketing director, and Mathew Wakelam, VoIP product manager, at alarm and communication specialist Static Systems Group, discuss wireless VoLP's potential in healthcare establishments and examine how, in particular, the technology can be successfully integrated with nurse call systems.

  2. Influencia de la aplicación de vinaza en actividad y biomasa microbiana en un Entic Dystropept y un Fluventic haplustoll del Valle del Cauca, Colombia

    Directory of Open Access Journals (Sweden)

    Bonilla Correa Carmen Rosa

    2009-03-01

    Full Text Available Con la aplicación de vinaza, residuo de la producción de alcohol carburante a partir de la caña de azúcar, se evaluó el efecto sobre la actividad y biomasa microbiana del suelo y el suministro de K+ al cultivo de maíz dulce (Zea Mays en un Entic Dystropept y un Fluventic Haplustoll del Valle del Cauca, Colombia. Se utilizó un diseño completamente al azar con cuatro tratamientos y cinco repeticiones: T1 (100% requerimiento de K+ con KCl, T2 (100% requerimiento de K+ con vinaza, T3 (50% requerimiento de K+ con KCl +50% con vinaza y T4 (25% requerimiento de K+ con KCl +75% con vinaza. Se estimó biomasa microbiana por el método de fumigación-extracción. Se realizó análisis de varianza, prueba de comparación de medias, regresiones y correlaciones (SAS. Se presentaron diferencias significativas en la actividad y biomasa microbiana por época de muestreo y entre los diferentes muestreos; al final del cultivo el Entic Dystropept presentó el contenido más alto de biomasa microbiana-C en el T2, mientras que en el Fluventic Haplustoll fue en el T1. El menor qCO2 fue para el T2 del Entic Distropept y T1 del Fluventic Haplustoll, estos tratamientos presentaron mayor acumulación de biomasa en cada suelo respectivamente T2 (30 450 kg ha-1 y T1 (21 015.6 kg ha-1.

  3. Implementation of a Prototype VoIP System

    Institute of Scientific and Technical Information of China (English)

    刘喜成; 李仲同

    2000-01-01

    VoIP (Voice over IP) is a rapidly growing area with great market potential. To promote it for both commercial and research purposes, a prototype VoIP system based on state-of-the-art Motorola communication techniques has been developed. It is a gateway system integrating a PBX and a VoIP module. All com ponents that H.323 defines to support VoIP are implemented in the VoIP module, though in a simplified manner. As an embedded system, the system features real timeness and task distributiveness. A number of additional techniques are used to improve the performance, including noise suppression, zero copy, and buffer structure optimization. When refined in interoperability, the system will also readily serve as a product.

  4. Fabrication and Characterization of Nanocrystalline VO2 Thin Films

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-Chen; YI Xin-Jian; LAI Jian-Jun; LI Yi

    2005-01-01

    @@ Nanocrystalline VO2 films with phase transition temperature 34℃ have been fabricated on Si3N4-film-coated silicon and quartz substrates by argon-annealing films of metastable VO2(B). The original VO2(B) films are obtained by ion beam sputtering in an argon-oxygen atmosphere at 200 ℃. The nanocrystalline VO2 films exhibit strong changes in electrical and optical properties when a phase transition is completed. The phase transition temperature in the as-fabricated samples is about 34 ℃, which is smaller in comparison with 68 ℃ in the singlecrystalline VO2 material. A lower phase transition temperature is favorable for device applications such as smart window coating and low power consumption optical switching.

  5. Improving the electrocatalytic performance of carbon nanotubes for VO2+/VO2+ redox reaction by KOH activation

    Science.gov (United States)

    Dai, Lei; Jiang, Yingqiao; Meng, Wei; Zhou, Huizhu; Wang, Ling; He, Zhangxing

    2017-04-01

    In this paper, carbon nanotubes (CNTs) was activated by KOH treatment at high temperature and investigated as catalyst for VO2+/VO2+ redox reaction for vanadium redox flow battery (VRFB). X-ray photoelectron spectroscopy results suggest that the oxygen-containing groups can be introduced on CNTs by KOH activation. The mass transfer of vanadium ions can be accelerated by chemical etching by KOH activation and improved wettability due to the introduction of hydrophilic groups. The electrochemical properties of VO2+/VO2+ redox reaction can be enhanced by introduced oxygen-containing groups as active sites. The sample treated at 900 °C with KOH/CNTs mass ratio of 3:1 (CNTs-3) exhibits the highest electrocatalytic activity for VO2+/VO2+ redox reaction. The cell using CNTs-3 as positive catalyst demonstrates the smallest electrochemical polarization, the highest capacity and efficiency among the samples. Using KOH-activated CNTs-3 can increase the average energy efficiency of the cell by 4.4%. This work suggests that KOH-activated CNTs is a low-cost, efficient and promising catalyst for VO2+/VO2+ redox reaction for VRFB system.

  6. FCC's Latest Action on VoIP Regulation%FCC关于VoIP管制的最新行动

    Institute of Scientific and Technical Information of China (English)

    张杰

    2005-01-01

    美国对VoIP管制问题的争论一直没有停止,从FCC最近一些行动来看,FCC试图通过911服务、执法侦听业务、税收等手段,加强对VoIP的监管力度.FCC进一步明确了VoIP的通信辅助执法法案(CALEA)的要求,重新提议对VoIP征税,但是,由于技术上的局限性,FCC也不得不延长对VoIP业务提供商的“紧急服务要求”期限.

  7. The Effect of Habitual Smoking on VO2max

    Science.gov (United States)

    Wier, Larry T.; Suminski, Richard R.; Poston, Walker S.; Randles, Anthony M.; Arenare, Brian; Jackson, Andrew S.

    2008-01-01

    VO2max is associated with many factors, including age, gender, physical activity, and body composition. It is popularly believed that habitual smoking lowers aerobic fitness. PURPOSE: to determine the effect of habitual smoking on VO2max after controlling for age, gender, activity and BMI. METHODS: 2374 men and 375 women employed at the NASA/Johnson Space Center were measured for VO2max by indirect calorimetry (RER>=1.1), activity by the 11 point (0-10) NASA Physical Activity Status Scale (PASS), BMI and smoking pack-yrs (packs day*y of smoking). Age was recorded in years and gender was coded as M=1, W=0. Pack.y was made a categorical variable consisting of four levels as follows: Never Smoked (0), Light (1-10), Regular (11-20), Heavy (>20). Group differences were verified by ANOVA. A General Linear Models (GLM) was used to develop two models to examine the relationship of smoking behavior on VO2max. GLM #1(without smoking) determined the combined effects of age, gender, PASS and BMI on VO2max. GLM #2 (with smoking) determined the added effects of smoking (pack.y groupings) on VO2max after controlling for age, gender, PASS and BMI. Constant errors (CE) were calculated to compare the accuracy of the two models for estimating the VO2max of the smoking subgroups. RESULTS: ANOVA affirmed the mean VO2max of each pack.y grouping decreased significantly (psmoking exposure increased. GLM #1 showed that age, gender, PASS and BMI were independently related with VO2max (R2 = 0.642, SEE = 4.90, pSmoked, the effects on VO2max from Light and Regular smoking habits were -0.83 and -0.85 ml.kg- 1.min-1 respectively (psmoking on VO2max was -2.56 ml.kg- 1.min-1 (psmoking group in GLM #2 was smaller than the CE s of the smoking group counterparts in GLM #1. CONCLUSIONS: After accounting for the effects of gender, age, PASS and BMI the effect of habitual smoking on reducing VO2max is minimal, about 0.85 ml/kg/min, until the habit exceeds 20 pack.y at which point an additional decrease

  8. Data access service of China-VO

    Science.gov (United States)

    Sang, Jian; Zhao, Yong-Heng; Cui, Chen-Zhou

    2004-09-01

    With the development of technologies and the implementation of large quantity of astronomical observation projects, astronomy faces data avalanche and has entered an information era. A basic aim of the Virtual Observatory is to provide uniform access to highly distributed, complicated, huge astronomical datasets, and to realize federation of global astronomical data resources, so that astronomers can obtain required data efficiently and conveniently for their research. China Virtual Observatory (China-VO) project designs and implements astronomical data access services based on Grid technology, and provides uniform interface to Grid client application. In this paper, we introduce the data access service toolkit development using Globus Toolkit, the Grid services encapsulation of catalogs according to the latest astronomical data standards recommended by International Virtual Observatory Alliance, the implements of catalog Cone Search access service. Furthermore, we also introduce how to construct other Grid services using above data access services.

  9. Factors determining the time course of VO2(max) decay during bedrest: implications for VO2(max) limitation.

    Science.gov (United States)

    Capelli, C; Antonutto, G; Kenfack, M Azabji; Cautero, M; Lador, F; Moia, C; Tam, E; Ferretti, G

    2006-09-01

    The aim of this study was to characterize the time course of maximal oxygen consumption VO2(max) changes during bedrests longer than 30 days, on the hypothesis that the decrease in VO2(max) tends to asymptote. On a total of 26 subjects who participated in one of three bedrest campaigns without countermeasures, lasting 14, 42 and 90 days, respectively, VO2(max) maximal cardiac output (Qmax) and maximal systemic O2 delivery (QaO2max) were measured. After all periods of HDT, VO2max, Qmax, and QaO2max were significantly lower than before. The VO2max decreased less than qmax after the two shortest bedrests, but its per cent decay was about 10% larger than that of Qmax after 90-day bedrest. The VO2max decrease after 90-day bedrest was larger than after 42- and 14-day bedrests, where it was similar. The Qmax and QaO2max declines after 90-day bedrest was equal to those after 14- and 42-day bedrest. The average daily rates of the VO2max, Qmax, and QaO2max decay during bedrest were less if the bedrest duration were longer, with the exception of that of VO2max in the longest bedrest. The asymptotic VO2max decay demonstrates the possibility that humans could keep working effectively even after an extremely long time in microgravity. Two components in the VO2max decrease were identified, which we postulate were related to cardiovascular deconditioning and to impairment of peripheral gas exchanges due to a possible muscle function deterioration.

  10. Integrating the IA2 Astronomical Archive in the VO: The VO-Dance Engine

    Science.gov (United States)

    Molinaro, M.; Laurino, O.; Smareglia, R.

    2012-09-01

    Virtual Observatory (VO) protocols and standards are getting mature and the astronomical community asks for astrophysical data to be easily reachable. This means data centers have to intensify their efforts to provide the data they manage not only through proprietary portals and services but also through interoperable resources developed on the basis of the IVOA (International Virtual Observatory Alliance) recommendations. Here we present the work and ideas developed at the IA2 (Italian Astronomical Archive) data center hosted by the INAF-OATs (Italian Institute for Astrophysics - Trieste Astronomical Observatory) to reach this goal. The core point is the development of an application that from existing DB and archive structures can translate their content to VO compliant resources: VO-Dance (written in Java). This application, in turn, relies on a database (potentially DBMS independent) to store the translation layer information of each resource and auxiliary content (UCDs, field names, authorizations, policies, etc.). The last token is an administrative interface (currently developed using the Django python framework) to allow the data center administrators to set up and maintain resources. This deployment, platform independent, with database and administrative interface highly customizable, means the package, when stable and easily distributable, can be also used by single astronomers or groups to set up their own resources from their public datasets.

  11. [Effect of 4 weeks of training on the limit time at VO2 max].

    Science.gov (United States)

    Heubert, Richard; Bocquet, Valéry; Koralsztein, Jean Pierre; Billat, Véronique

    2003-10-01

    The purpose of this study was to examine the effect of 4 weeks training in running on the time spent at VO2max (tlim VO2max). Eight athletes carried out, before and after an aerobic training, an incremental and five exhaustive tests at 90, 95, 100, 115% vVO2max and at the critical power at VO2max (CV'; slope of the linear relation between the tlim VO2max and the distance limit at VO2max). This training did not significantly improve VO2max (p = 0.17) or tlim VO2max (p = 0.72). However, the "tlim VO2max-intensity" curve was shifted toward the right, meaning that the athlete had to run at a higher intensity after training to obtain the same tlim VO2max. Tlim VO2max at CV' before training was significantly higher than tlim VO2max at 90, 95, 100, and 115% vVO2max (p max; p = 0.9). In conclusion, in spite of the shift of the "tlim VO2max-intensity" curve, tlim VO2max was not significantly increased by this training. Furthermore, CV' allowed subjects to spend the longest time of exercise at VO2max during a continuous exercise with constant speed, but CV', expressed in % vVO2max, did not improve with this training.

  12. Leg strength and the VO2 max of older men.

    Science.gov (United States)

    Lovell, D; Cuneo, R; Delphinus, E; Gass, G

    2011-04-01

    The purpose of the study was to determine if leg strength limits VO2 max and the ability to reach a plateau during VO2 max test in older men during cycle ergometry. Men aged 70-80 years were randomly selected into a strength training (ST, n=12) 3 times weekly for 16 weeks, followed by 4 weeks detraining or a non-training control group (C, n=12). Leg strength and VO2 max were assessed every 4 weeks for 20 weeks; body composition and cardiac function were assessed before and after 16 weeks training and after 4 weeks detraining. Leg strength, upper leg muscle mass (ULMM), arterial-venous O2 difference (a-v O2 difference) and VO2 max increased in the ST group (95±0.6%, 7±0.7%. 6.2±0.5% and 8±0.8%, respectively; PVO2 max and a-v O2 difference returned to pre-training levels. There was no change in the ability of the participants to reach a plateau during VO2 max testing over the 20-week study. These findings indicate that leg strength may not limit either VO2 max or the ability to plateau during VO2 max tests in older men during cycle ergometry.

  13. Polymorphism of Ag{sub 3}VO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Dinnebier, R.E.; Jansen, M. [Max-Planck-Inst. for Solid State Research, Stuttgart (Germany); Reichert, H. [Max-Planck-Inst. for Metal Research, Stuttgart (Germany); Kowalevsky, A.

    2007-07-01

    The polymorphism of Ag{sub 3}VO{sub 4} was investigated with temperature dependent synchrotron powder diffraction, and differential scanning calorimetry in the temperature range 295 K {<=} T {<=} 893 K. Three crystal structures of Ag{sub 3}VO{sub 4} were identified and determined from powder diffraction data: a-Ag{sub 3}VO{sub 4} (T = 295 K, C2/c, a = 10.2672(2) Aa, b = 4.9814(1) Aa, c = 10.2240(2) Aa, {beta} = 116.0(1) , V = 470.0(2) Aa{sup 3}), {beta}-Ag{sub 3}VO{sub 4} (T = 423 K, I anti 42m, a = 4.9968(1) Aa, c = 9.6911(3) Aa, V = 241.97(1) Aa{sup 3}), and {gamma}-Ag{sub 3}VO{sub 4} (T = 703 K, Fm anti 3m, a = 7.8386(1) Aa, V = 481.62(1) Aa{sup 3}). The crystal structures of all three phases of Ag{sub 3}VO{sub 4} can be described as cubic closed packed arrangements of [VO{sub 4}]{sup 3-} anions with the silver cations occupying all octahedral and tetrahedral voids. (orig.)

  14. Epitaxial Ni/VO2 heterostructures on Si (001)

    Science.gov (United States)

    Singamaneni, Srinivasa Rao; Foley, Gabrielle; Prater, John; Narayan, Jay

    VO2 is a strongly correlated oxide, undergoes a first order metal-insulator (MIT) well above the room temperature 340K. Previous works have shown that the stress associated with structural changes across MIT, VO2 can produce significant changes in magnetic properties of over layer ferromagnetic films such as Ni. This control of the magnetic properties could be very important to many technological applications. However, the current use of r-sapphire as substrate can be restrictive in the microelectronics industry. The previous works focused their studies on polycrystalline Ni and VO2 films, which do not allow the precise controlling of the associated properties due to poor reproducibility of polycrystalline films. We have investigated the magnetic and electronic properties of Ni/VO2 films when epitaxially integrated on Si (001) by pulsed laser deposition using domain matching epitaxy paradigm. Ni was grown both in nanoscale islands and layered form. The XRD results showed that the Ni, VO2and YSZ layers were grown epitaxially in single out of plane orientations. We found that the hysteresis in resistance vs. temperature curves in VO2 thin films was retained even when it is in close proximity with the Ni layer which helped confirm that VO2 layer preserves its characteristic features, revealed the fingerprint magnetic features of Ni layer. We will present and discuss our comprehensive experimental findings.

  15. Biosorción de iones cobre con biomasa de algas y orujos deshidratados

    Directory of Open Access Journals (Sweden)

    Romero, L.

    2011-02-01

    Full Text Available They were carried out experiments of biosorption batch and in continuous to remove copper from aqueous solutions using as adsorbent green algae and olive residues under virgins conditions and chemically activated. The results of batch biosorption indicate that the algae present mayor elimination capacities than the waste of olives, with uptakes of copper of the order of 96 % using activated algae with dissolution of Na2SO4 under the optimum conditions. The results of the columns tests show that the virgin algae permits the removal of more copper ions than the activate algae, with removal efficiency of 98 % during the firth 20 min, a breakthrough time of 240 min and a saturation at time of 600 min. In the second cycle the regenerated biomass showed a best performance indicating that they can be used for another biosorption cycle.

    Se realizaron experimentos de biosorción batch y en continuo para remover cobre desde soluciones acuosas usando como adsorbentes algas verdes y residuos de aceituna en condiciones vírgenes y activadas químicamente. Los resultados de la biosorción a escala batch indican que las algas presentan mayor capacidad de eliminación que los orujos, alcanzándose captaciones de cobre del orden de 96 % con algas activadas con disoluciones de Na2SO4 bajo condiciones óptimas de las variables estudiadas. Los resultados de los ensayos en columna muestran que las algas vírgenes captan más iones cobre que las activadas con Na2SO4, con eficacias de eliminación del 98 % durante los primeros 20 min, con un tiempo de ruptura de 240 min y una saturación a los 600 min. Al ser sometidas a un segundo ciclo de biosorción, las algas regeneradas muestran un mejor rendimiento lo que indica que pueden ser usadas en otro ciclo de eliminación.

  16. Productividad y biomasa fitoperifítica en los Lagos Tarapoto y Yahuarcaca, Amazonas, Colombia Productividad y biomasa fitoperifítica en los lagos Yahuarcaca y Tarapoto (Amazonas - Colombia

    Directory of Open Access Journals (Sweden)

    Duque Escobar Santiago R.

    2000-06-01

    Full Text Available In the littoral zone, near of the matrix the macrophytes, main for Paspalum spp the lake Yahuarcaca and Tarapoto; the floodplain of the Amazon River-Colombia, through were designed system of artificial substratum, using slips and rods we quantify the productivity primary phytoperiphyton for clorophyl a, through method espectrophotometric and the biomass for ash free dry weight; in three periods hidrology low water, filling water and high water; for two, four and eigh day the colonization; four deep levels and radial position the substratum. The factors that has mayor effect over the primary productivity and the biomass phytoperiphytic are the hidrobiology periods, the colonization of the substratum and deep. The productivity and biomass from the lake is reationship with the mineralization of the water, with the tramsportation of nutrients of afluents, macrophytes, the flood forest, decomposition and the recirculation of nutrients in the water column.En la zona litorial, cerca de la matriz de macrófitas conformadas principalmente por Paspalum spp de los lagos Yahuarcaca y Tarapoto, del plano de inundación del Río Amazonas-Colombia, mediante el diseño de un sistema de substratos artificiales, utilizando láminas portaobjetos y tubos de vidrio, se cuantificó la productividad primaria fitoperifítica por clorofila a, mediante el método espectrofotométrico y la biomasa por peso seco libre de cenizas (PSLC, en tres períodos hidrológicos, aguas bajas, ascenso y altas o desborde; a los 2, 4 y 8 días de colonización; cuatro niveles de profundidad (cada 10

  17. Auvi PHIP100多功能VoIP电话

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    VoIP电话已经算得上是一片风靡,推出相关服务的运营商也是越来越多,但工作在这一网络下的电话却又是“年年岁岁花相似”。好在Auvi最新推出的PHIP 100多功能VoIP电话让我们有了新鲜的感觉。除去和普通VoIP电话相去不远的听筒。

  18. Improvement on QoS of VoIP

    Institute of Scientific and Technical Information of China (English)

    HUANGYongfeng; LIXing; RUANFang

    2003-01-01

    This paper first introduces some factors affecting QoS of VoIP System, and presents some strategies to improve VoIP speech quality. Studies are concentrated on an adaptive algorithms based on IP telephony gateway, which includes adopting buffer to smooth the jitter, low bit rate redundancy packet sending mechanism to recover the packet loss, a delay and loss measurement mechanism based on RTP (Real-time transmit protocol), and an adaptive scheme algorithm according to the loss ratio and end to end delay. Finally, the results of testing have denoted that these adaptive mechanisms applied in gateway can improve greatly QoS of VoIP.

  19. Estimación de Iluminación en un Fotobiorreactor Productor de Biomasa a Partir de Microalgas

    Directory of Open Access Journals (Sweden)

    Carlos Francisco González Hernández

    2014-01-01

    Full Text Available En el presente trabajo se realizó el análisis de iluminación artificial para un fotobiorreactor productor de biomasa a partir de microalgas, el cual fue diseñado previamente con fines en aplicación para la producción de biocombustibles. En el análisis, se utilizó como herramienta la técnica de contornos o también conocida como método de superficie de respuesta, para lo cual se establecieron 132 puntos de intensidad luminosa distribuidos de forma simétrica a diferentes alturas del contenedor. Se realizaron dos bioensayos uno con la iluminación en la parte inferior del recipiente usando Diodos Emisores de Luz (LED’s, por sus siglas en inglés y el otro adicionando 3 lámparas fluorescentes más, situadas periféricamente a la mitad de la altura total del fotobiorreactor. Los resultados de las mediciones muestran una mejoría en el sistema de iluminac ión que favorece la reproducción continua de las microalgas, cuando se utilizó la combinación de luz emitida por LED’s y por lámparas fluorescentes. Esta combinación de sistemas de iluminación generó las condiciones para poder realizar las funciones metabólicas de las microalgas, quienes necesitan en promedio 2500 lx de forma homogénea.

  20. Enterprise VoIP System Construction with TrixBox%用TrixBox构建企业VoIP系统

    Institute of Scientific and Technical Information of China (English)

    王爱民

    2009-01-01

    VoIP(Voice over Internet Protocol)是一种以IP电话为主,并推出相应的增值业务的技术.通过对VoIP系统的分析,介绍了如何利用开源软件Trixbox来构建一个企业内部的VoIP通信网络.从而实现将数据网与电话网二网合一,不仅极大的提高企业内部协同工作的效率,而且节省大量的费用.

  1. Secuestro de carbono en la biomasa aérea de un sistema agrosilvopastoril de Cocos nucifera, Leucaena leucocephala Var. Cunningham y Pennisetum purpureum Cuba CT-115

    OpenAIRE

    J. M. Anguiano; Aguirre, J.; Palma, J.M. (José Manuel)

    2013-01-01

    Con el objetivo de estimar el secuestro de carbono en la biomasa aérea de un sistema agrosilvopastoril (sasp) compuesto por cocotero (Cocos nucifera), Leucaena leucocephala Var. Cunningham sembrada en alta densidad y Pennisetum purpureum Cuba CT-115, se llevó a cabo un estudio en un suelo con textura franco arcillo- arenosa. Se utilizó un diseño en bloques al azar con arreglo en parcelas divididas con cuatro tratamientos 0, 40, 60 y 80 mil árboles de leucaena ha-1 y tres repeticiones; la eval...

  2. EVALUACIÓN DE LA BIOMASA Y MANEJO DE Lemna gibba (LENTEJA DE AGUA) EN LA BAHÍA INTERIOR DEL LAGO TITICACA, PUNO

    OpenAIRE

    Canales-Gutiérrez, Ángel; Facultad de Ciencias Biológicas UNA PUNO (Perú).

    2010-01-01

    Uno de los mayores problemas que enfrenta la ciudad de Puno es la presencia de la lenteja de agua (Lemna gibba) en la bahía interior del Lago Titicaca, debido al proceso de eutrofización que sufre a causa del mal tratamiento de las aguas residuales de la ciudad de Puno. Muchas de las estrategias planteadas hasta ahora no han dado resultados positivos en la reducción de la biomasa de Lemna gibba, debido a que estos planes están direccionados a la exterminación de este organismo. En lugar de el...

  3. NUEVAS PERSPECTIVAS PARA EL ESTUDIO DE LA ASIGNACIÓN DE BIOMASA Y SU RELACIÓN CON EL FUNCIONAMIENTO DE PLANTAS EN ECOSISTEMAS NEOTROPICALES

    Directory of Open Access Journals (Sweden)

    IVÁN DARÍO CAMARGO RODRÍGUEZ

    2006-01-01

    Full Text Available Cómo responden las plantas a la variabilidad en la disponibilidad de los recursos abióticos, es un tema central en estudios de fisiología ecológica. Varios modelos de partición óptima han sugerido un balance funcional en la biomasa asignada al vástago y la raíz con la siguiente predicción: "las plantas cambiarían su asignación de biomasa hacia el vástago si la ganancia de carbono de la parte aérea de la planta es afectada por un nivel bajo de recursos sobre el suelo, tal como luz o CO2. Igualmente, las plantas cambiarían su asignación hacia la raíz si el nivel de los recursos del suelo es bajo, tal como nutrientes y agua". Estos cambios en la asignación pueden ser con- siderados como adaptativos, ya que permiten a la planta capturar más de aquel recurso que limita fuertemente su crecimiento. En este trabajo, discutimos algunos esquemas metodológicos que a través de la descripción y análisis de la asignación de biomasa pretenden probar dicha predicción. Enfatizamos que la conclusión extraída en contra o a favor de la predicción se fundamenta en la interpretación del término plasticidad, conllevando recientemente al uso de metodologías que sugieren que la predicción no se cumple en respuesta a la disponibilidad de algunos recursos. Proponemos la utilización de un protocolo de investigación para estudiar los patrones de asignación de biomasa y sugerimos una metodología para cuantificar la plasticidad de diferentes genotipos desde un punto de vista discreto.

  4. Estudio de la oxidación a elevada temperatura de ocho aleaciones en atmósferas de combustión de biomasa

    Directory of Open Access Journals (Sweden)

    Berlanga-Labari, C.

    2008-08-01

    Full Text Available The combustion of biomass, especially wheat straw, generates very corrosive media particularly near the superheater tubes. Chlorine is known to be the main corrosive agent in biomass-fired plants. This paper focuses on the study of the corrosivity of such environments composed of gases and ashes, at high temperature, on eight commercial alloys with different chromium and nickel contents. These have been: AISI 347 CG (1.4550, AISI 347 FG(1.4550, AISI 316LN (1.4910, ESSHETE 1250 (1.4982, AC 66 (1.4877, X20CrMoV12:1 (1.4922 and AISI 347 coated with Inconel 625 and Inconel 686. Corrosion tests in the boiler have been performed during 8.000 h and 15.000 h at temperatures between 500 °C y 550 °C in the biomass plant of Sangüesa (Navarra, Spain. Experimental results showed an unacceptable behaviour far the martensitic steel, acceptable far the austenitics and good far the inconels. The appearance of the corrosion attack was also investigated to obtain understanding of the corrosion mechanism. The corrosion mechanism by molten salts has been rejected. The active oxidation corrosion mechanism has been proposed as the most probable in order to interpretate the corrosion behaviour of these materials in these environments.

    La combustión de biomasa, especialmente de paja de cereal, genera un ambiente muy corrosivo, particularmente, cerca de los tubos sobrecalentadores. El cloro es el principal agente corrosivo en las plantas de biomasa. Este trabajo se centra en comprobar el comportamiento de ocho aleaciones comerciales en una ambiente de combustión de biomasa. Los materiales estudiados han sido las siguientes: AISI 347 CG (1.4550, AISI 347 FG (1.4550, AISI 316LN (1.4910, ESSHETE 1250 (1.4982, AC 66 (1.4877, X20CrMoV12:1 (1.4922 y AISI 347 recubiertos con Inconel 625 e Inconel 686. Los ensayos se han realizado en la caldera de la planta de biomasa de Sangüesa (Navarra, España durante 8.000 y 15.000 h a una temperatura de 500-550 °C. Los

  5. Crecimiento, Abundancia Y Biomasa De Poecilia reticulata En El Lago Urbano Del Parque Tezozomoc De La Ciudad De México

    OpenAIRE

    2006-01-01

    Los lagos urbanos tienen importancia estética, recreativa, cultural y biológica por albergar organismos generalmente alóctonos, como aves, reptiles, insectos y peces, en particular poecilidos, los cuales son muy tolerantes y se reproducen con facilidad. Por lo anterior, el objetivo de este trabajo fue: determinar la variación en la abundancia y biomasa de Poecilia reticulata en el lago del parque Tezozomoc, así como obtener la ecuación de crecimiento. Se realizaron muestreos mensuales de juli...

  6. LA BIOMASA COMO ALTERNATIVA AL PETRÓLEO PARA LA OBTENCIÓN DE PRODUCTOS QUÍMICOS: ACETONA Y ETANOL COMO MOLÉCULAS PLATAFORMA

    OpenAIRE

    Jorge Quesada; Laura Faba; Eva Díaz; Salvador Ordóñez

    2014-01-01

    En este trabajo se pretende reflejar el potencial de la biomasa como materia prima para la obtención de productos químicos de elevado valor añadido, integrando su viabilidad económica y técnica dentro del concepto de biorefinería. Considerando el gran número de trabajos existentes acerca de la obtención de biocombustibles, se hace hincapié en el aprovechamiento de los subproductos de estos procesos, abordando la transformación de dos de las moléculas plataforma de mayor proyección: el etanol ...

  7. Estudio teórico de la combustión de pellets de biomasa procedente de la caña de azúcar

    OpenAIRE

    David Verdecia Torres; Idalberto Macías Socarrás; Benjamín Gabriel Gaskins Espinosa

    2012-01-01

    En el siguiente trabajo se examina la cinética química de la combustión de pellets de biomasa cañera, se obtiene el tiempo de combustión en función de la etapa controlante del proceso de combustión según el modelo de núcleo sin reaccionar, además se realiza un diseño de experimento para determinar los modelos matemáticos teóricos para modelar el proceso de combustión.

  8. BiVO4 nanoparticles: Preparation, characterization and photocatalytic activity

    Directory of Open Access Journals (Sweden)

    Venkataraman Sivakumar

    2015-12-01

    Full Text Available Bismuth vanadate (BiVO4 nanoparticles were synthesized by a simple thermal decomposition method. The synthesized bismuth vanadate nanoparticles were characterized by X-ray diffraction analysis, it is found that the synthesized sample belongs to monoclinic BiVO4. Fourier transform infrared spectroscopy confirms the formation of Bi-O bond in the sample. Ultraviolet–Visible (DRS-UV–Visible spectroscopy and photoluminescence spectroscopy reveal the optical property of the BiVO4 nanoparticles. The morphology was identified by both scanning electron microscopy and high-resolution transmission electron microscopy. Further, the photocatalytic activity of BiVO4 nanoparticles was investigated by photodegradation of methylene blue as a model organic pollutant.

  9. Audio CAPTCHA for SIP-Based VoIP

    Science.gov (United States)

    Soupionis, Yannis; Tountas, George; Gritzalis, Dimitris

    Voice over IP (VoIP) introduces new ways of communication, while utilizing existing data networks to provide inexpensive voice communications worldwide as a promising alternative to the traditional PSTN telephony. SPam over Internet Telephony (SPIT) is one potential source of future annoyance in VoIP. A common way to launch a SPIT attack is the use of an automated procedure (bot), which generates calls and produces audio advertisements. In this paper, our goal is to design appropriate CAPTCHA to fight such bots. We focus on and develop audio CAPTCHA, as the audio format is more suitable for VoIP environments and we implement it in a SIP-based VoIP environment. Furthermore, we suggest and evaluate the specific attributes that audio CAPTCHA should incorporate in order to be effective, and test it against an open source bot implementation.

  10. Auvi PHIP 100多功能VoIP电话

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    VoIP风暴冲击下,现在商务办公的通信模式已经发生了显著的变化,越来越多专为VoIP技术研发的新通信设备更是升温了这场封杀传统电话的“颜色革命”。Auvi PHIP100多功能VoIP电话是一款使用无线技术的VoIP电话,不同之处在于它非常在意对影像效果——附带的底座上有一个高清晰的摄像头,

  11. Estimativa das contribuições dos sistemas anaeróbio lático e alático durante exercícios de cargas constantes em intensidades abaixo do VO2max Estimation of contributions of the anaerobic lactic and alactic systems during constant-load exercises at intensities below the VO2max

    Directory of Open Access Journals (Sweden)

    Marcos David Silva-Cavalcante

    2013-01-01

    Full Text Available O objetivo do estudo foi estimar as contribuições do metabolismo anaeróbio lático (MAL e alático (MAA em intensidades abaixo do consumo máximo de oxigênio (VO2max. Dez homens (23 ± 4 anos, 176,4 ± 6,8 cm, 72,4 ± 8,2 kg, 12,0 ± 4,5 % de gordura corporal realizaram um teste progressivo até a exaustão voluntária para identificação do VO2max, da potência correspondente ao VO2max (WVO2max e do segundo limiar ventilatório (LV2. Na segunda e na terceira visita foram realizados seis testes de cargas constantes (três testes por sessão com intensidades abaixo do VO2max. Houve uma predominância do MAL sobre o MAA durante os exercícios submáximos a partir da intensidade correspondente ao LV2, sendo significativamente maior em 90% VO2max (p The purpose this study was that estimated contributions of the anaerobic lactic (MAL and alactic (MAA metabolism during constant load exercises at intensities below the maximal oxygen capacity uptake (VO2max. Ten males (23 ± 4 years, 176.4 ± 6.8 cm, 72.4 ± 8.2 kg, 12.0 ± 4.5 % of fat body performed in the first visit a progressive test until exhaustion to identification of VO2max, power output corresponding to the VO2max (WVO2max and second ventilatory threshold (LV2. On the second and third visit, the participants performed six constant workload tests (3 per session with intensities below VO2max. There was a predominance of MAL about MAA during the exercises sub-maximal from intensity corresponding to the LV2, being significantly higher at 90% VO2max (p < 0.05. Thus, these results may help coaches to implement training loads appropriate to their athletes, according to the metabolic demand of the competition.

  12. Caracterización de la distribución de la biomasa y densidad de raíces finas en un gradiente sucesional de bosques en la Zona Norte de Costa Rica.

    OpenAIRE

    Jiménez-Rodríguez, César

    2004-01-01

    Informe Final de Proyecto de Investigación. En este estudio se evaluó la distribución de la biomasa radical, el índice de área radical (RAI) y la densidad longitudinal (RLD) de raíces finas (< 5 mm) en una gradiente sucesional de bosques húmedos tropicales en la zona de Florencia de San Carlos, Costa Rica. La variación de estos parámetros se evaluaron en función de la profundidad del suelo y del estado sucesional. La biomasa radical al igual que el RAI y el RLD disminuyen conforme aumenta ...

  13. Crystal structure and electrical properties of K 3Bi 2(VO 4) 3, a new potassium bismuth vanadate

    Science.gov (United States)

    Debreuille-Gresse, M. F.; Abraham, F.

    1987-12-01

    K 3Bi 2(VO 4) 3 crystallizes in the space group {C2}/{c}, a = 13.957(4), b = 13.858(4), c = 7.095(2) Å, β = 112.80(3)°, Z = 4. The crystal structure was determined from single-crystal intensity data obtained by means of an automated four-circle diffractometer and refined to the conventional values R = 0.050 and Rw = 0.059 for 1498 observed reflections. The structure is characterized by a three-dimensional network of Bi 2O 10 units and VO 4 tetrahedra. A Bi 2O 10 unit is formed by two BiO 6 octahedra sharing an edge. K + ions occupy three different crystallographic sites. One of them has a high thermal vibration which could reflect ionic mobility. The ionic conductivity highly increases at 790 K. DSC measurements show a reversible transition at this temperature. One K atom, and only one, can be substituted by one Na atom to give NaK 2Bi 2(VO 4) 3; this substitution improves the conductivity.

  14. Fair Scheduling for Delay-Sensitive VoIP Traffic

    Science.gov (United States)

    Ahmed, Shawish; Jiang, Xiaohong; Horiguchi, Susumu

    With the wide expansion of voice services over the IP networks (VoIP), the volume of this delay sensitive traffic is steadily growing. The current packet schedulers for IP networks meet the delay constraint of VoIP traffic by simply assigning its packets the highest priority. This technique is acceptable as long as the amount of VoIP traffic is relatively very small compared to other non-voice traffic. With the notable expansion of VoIP applications, however, the current packet schedulers will significantly sacrifice the fairness deserved by the non-voice traffic. In this paper, we extend the conventional Deficit Round-Robin (DRR) scheduler by including a packet classifier, a Token Bucket and a resource reservation scheme and propose an integrated packet scheduler architecture for the growing VoIP traffic. We demonstrate through both theoretical analysis and extensive simulation that the new architecture makes it possible for us to significantly improve the fairness to non-voice traffic while still meeting the tight delay requirement of VoIP applications.

  15. 基于MANET的VoIP系统研究%Research on the VoIP System based on MANET

    Institute of Scientific and Technical Information of China (English)

    俞凡

    2006-01-01

    由于MANET自组织、无中心等特点,传统的VoIP体系结构不能直接应用在MANET之上,这就要求对传统VoIP系统进行一定的改造,使之能够适应MANET环境.本文提出将P2P的簇状组网结构引入SIP,从而可以在MANET上构建基于SIP的可灵活扩展的VoIP通信系统,分析了在该架构中的主要操作的典型工作机制,采用本方案的VoIP系统既可以适应MANET环境的需求,又可以与现有的SIP系统无缝通信.本文最后展望了未来的研究方向.

  16. Polycrystalline VO{sub 2} thin films via femtosecond laser processing of amorphous VO{sub x}

    Energy Technology Data Exchange (ETDEWEB)

    Charipar, N.A.; Kim, H.; Charipar, K.M.; Mathews, S.A.; Pique, A. [Naval Research Laboratory, Materials Science and Technology Division, Washington, DC (United States); Breckenfeld, E. [National Research Council Fellow at the Naval Research Laboratory, Washington, DC (United States)

    2016-05-15

    Femtosecond laser processing of pulsed laser-deposited amorphous vanadium oxide thin films was investigated. Polycrystalline VO{sub 2} thin films were achieved by femtosecond laser processing in air at room temperature. The electrical transport properties, crystal structure, surface morphology, and optical properties were characterized. The laser-processed films exhibited a metal-insulator phase transition characteristic of VO{sub 2}, thus presenting a pathway for the growth of crystalline vanadium dioxide films on low-temperature substrates. (orig.)

  17. 基于DPI技术的VoIP流量识别%VoIP Traffic Identification Based on DPI Technology

    Institute of Scientific and Technical Information of China (English)

    肖玲玲; 高林; 张扬

    2013-01-01

    As the openness and freedom of the IP network, and the ease of use of the VoIP technology, in the telecommunica-tions market there are a lot illegal VOIP business, the operators lack effective regulatory program on the network traffic, the con-sequences are the loss of legitimate traffic carriers and the lower profits. This paper focuses on the VoIP traffic detection method using DPI technology, deeply analyses various popular software applications based on VoIP protocol, design and implement a net-work traffic detection and identification system that can meet the VoIP network traffic identification and records.%由于IP网络的开放性和自由性,VoIP接入技术的简单易行,在电信市场中存在着大量非法的VOIP业务,网络运营商对网络流量缺少有效的监管方案,结果是合法运营商的话务量流失,利润下降。该文重点研究了运用DPI技术检测VoIP流量的方法,深入分析了各种基于VoIP协议流行的应用软件,设计和实现了一个网络流量检测识别系统,能够满足对VoIP网络流量的识别和记录。

  18. Template-Engaged In Situ Synthesis of Carbon-Doped Monoclinic Mesoporous BiVO4: Photocatalytic Treatment of Rhodamine B

    Science.gov (United States)

    Yao, Mingming; Gan, Lihua; Liu, Mingxian; Tripathi, Pranav K.; Liu, Yafei; Hu, Zhonghua

    2015-06-01

    In this paper, carbon-doped monoclinic scheelite mesoporous bismuth vanadate was synthesized through template-engaged in situ method. The bismuth nitrate pentahydrate and ammonia metavanadate were used as bismuth and vanadium precursors, respectively, glucose as carbon source, and mesoporous SiO2 aerogel as a hard template. Carbon-doped monoclinic mesoporous BiVO4 were obtained by heat treatment of BiVO4/glucose/template to carbonize glucose and form monoclinic crystal, followed by etching with NaOH solution to remove the SiO2 template. The samples were characterized by x-ray diffraction, N2 adsorption and desorption, UV-visible spectroscopy, Energy dispersive spectrometry, Raman spectroscopy, and Transmission electron microscopy. It was found that the sample with a carbon content of 0.5 wt.% possesses a specific surface area of 10.2 m2/g and has mesoporous structure with the most probable pore size of 13.9 nm. The band gap of carbon-doped monoclinic mesoporous BiVO4 was estimated to be 2.33 eV, indicating the superior photocatalytic activity under visible light. The photocatalytic efficiency of carbon-doped monoclinic mesoporous BiVO4 for the degradation of Rhodamine B under visible light (λ > 400 nm) in 120 min reaches 98.7%, Besides, the carbon-doped monoclinic mesoporous BiVO4 photocatalyst still showed high stability: 85% for Rhodamine B degradation after ten recycles.

  19. VO-Dance an IVOA tools to easy publish data into VO and it's extension on planetology request

    Science.gov (United States)

    Smareglia, R.; Capria, M. T.; Molinaro, M.

    2012-09-01

    Data publishing through the self standing portals can be joined to VO resource publishing, i.e. astronomical resources deployed through VO compliant services. Since the IVOA (International Virtual Observatory Alliance) provides many protocols and standards for the various data flavors (images, spectra, catalogues … ), and since the data center has as a goal to grow up in number of hosted archives and services providing, the idea arose to find a way to easily deploy and maintain VO resources. VO-Dance is a java web application developed at IA2 that addresses this idea creating, in a dynamical way, VO resources out of database tables or views. It is structured to be potentially DBMS and platform independent and consists of 3 main tokens, an internal DB to store resources description and model metadata information, a restful web application to deploy the resources to the VO community. It's extension to planetology request is under study to best effort INAF software development and archive efficiency.

  20. Correlação entre as medidas direta e indireta do VO2max em atletas de futsal Correlación entre las medidas directa e indirecta del VO2max en atletas de futsal Correlation between direct and indirect VO2max measurements in indoor soccer players

    Directory of Open Access Journals (Sweden)

    Anna Myrna Jaguaribe de Lima

    2005-06-01

    Full Text Available A importância das qualidades morfofuncionais na melhora do rendimento nos esportes aumentou o interesse no aprimoramento dos níveis de aptidão física dos atletas. No entanto, há poucos estudos sobre as variáveis fisiológicas do futsal disponíveis na literatura científica mundial. Dessa forma, o objetivo deste estudo foi verificar a existência de correlação entre os testes de medida direta e indireta do VO2max, em jogadores de futsal. Foram analisados 13 jogadores de futsal, com idade de 18,6 ± 1,9 anos, altura igual a 177,1 ± 3,5cm, peso de 68,5 ± 9,5kg, índice de massa corporal (IMC de 21,7 ± 2,3kg/m². Para medida direta do VO2max foi utilizado o sistema ergoespirométrico computadorizado (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota e para mensuração indireta do VO2max foi realizado o teste de campo de 3.200m. A análise estatística foi elaborada através do teste t de Student para amostras pareadas e pelo coeficiente de correlação de Pearson. Os valores de VO2max obtidos no teste de medida direta não apresentaram diferenças significativas em relação à medida indireta (62,8 ± 10,1 vs. 58,5 ± 8,5ml/kg/min, respectivamente. Quando correlacionados os valores de VO2max obtidos em ambos os testes, observou-se forte correlação (r = 0,72. Em conclusão, os testes de medida indireta apresentam boa aceitação para os atletas de futsal, tendo em vista a alta correlação com os testes de medida direta, o baixo custo de sua aplicação e o fornecimento de informações importantes que podem auxiliar na prescrição e no acompanhamento do treinamento.La importância de las cualidades morfo-funcionales en la mejora del rendimiento en los deportes aumentó el interes en el acondicionamiento de los niveles de aptitud física de los atletas. En tanto, hay pocos estudios sobre las variables fisiológicas del futsal disponibles en la literatura mundial. De esta forma, el objetivo del estudio fué verificar la existencia

  1. Efectos de vinazas sobre bacterias rizosféricas y en la actividad-CO2 y biomasa-C microbiana de un suelo Pachic Haplustoll

    Directory of Open Access Journals (Sweden)

    Miriam Rosero G

    2013-04-01

    Full Text Available En condiciones de casa de malla de la Universidad Nacional de Colombia sede Palmira se estudió los efectos de la aplicación de vinaza, un subproducto de la industria de alcohol carburante, sobre las bacterias rizosféricas Pseudomonas fluorescens y Bacillus subtilis promotoras de crecimiento, la actividad-CO2, biomasa microbiana-C y el cociente metabólico-qCO2 en un suelo Pachic Haplustoll y su relación con el rendimiento de habichuela (Phaseolus vulgaris L.. Se utilizó un diseño completamente al azar con siete tratamientos y cinco repeticiones. Los tratamientos se seleccionaron con base en los requerimientos de K del cultivo (150 kg/ha K2O utilizando como fuentes KCl y vinaza solos y en mezclas. Los tratamientos evaluados y la época de muestreo influyeron (P < 0.05 en la actividad y biomasa microbiana. Los menores valores de estas variables se presentaron en la época de floración del cultivo cuando la demanda de nutrientes es alta. La mezcla en partes iguales de vinaza y KCl favorece la mayor producción de habichuela sin afectar la actividad microbiana; el cociente metabólico indicó estabilidad del sistema en el tiempo y las bacterias rizosféricas presentaron el mejor crecimiento en la mezcla 75% de potasio como vinaza y 25% como KCl.

  2. Spectroscopic Analysis in the Virtual Observatory Environment with SPLAT-VO

    CERN Document Server

    Skoda, Petr; Neves, Margarida Castro; Andresic, David; Jenness, Tim

    2014-01-01

    SPLAT-VO is a powerful graphical tool for displaying, comparing, modifying and analyzing astronomical spectra, as well as searching and retrieving spectra from services around the world using Virtual Observatory (VO) protocols and services. The development of SPLAT-VO started in 1999, as part of the Starlink StarJava initiative, sometime before that of the VO, so initial support for the VO was necessarily added once VO standards and services became available. Further developments were supported by the Joint Astronomy Centre, Hawaii until 2009. Since end of 2011 development of SPLAT-VO has been continued by the German Astrophysical Virtual Observatory, and the Astronomical Institute of the Academy of Sciences of the Czech Republic. From this time several new features have been added, including support for the latest VO protocols, along with new visualization and spectra storing capabilities. This paper presents the history of SPLAT-VO, it's capabilities, recent additions and future plans, as well as a discussi...

  3. Consideraciones sobre la producción de etanol a partir de la biomasa lignocelulósica

    Directory of Open Access Journals (Sweden)

    José C. Villar

    2008-01-01

    Full Text Available En los últimos años, como consecuencia del aumento de los precios del petróleo y las exigencias ecológicas, ha crecido el interés por la producción de bioetanol como combustible de vehículos automotores. En Brasil y EEUU, los principales productores, se estima una producción por cada país en el 2006 de alrededor de los 19 mil millones de litros. Brasil planea aumentar la producción hasta 26.5 mil millones en el 2016 mientras que para esa misma fecha EEUU pretende alcanzar los 45,4 mil millones de litros. Las materias primas más empleadas son maíz y caña de azúcar. Sería de interés incluir entre éstas a la biomasa lignocelulósica que se obtiene como subproductos agrícolas y forestales (pajas de cereales, bagazo, aserrín y virutas de madera que no son aptos para el consumo humano y por su composición química son susceptibles de ser sacarificados por hidrólisis química o enzimática. Se analizan críticamente las posibles vías para desarrollar la producción de alcohol a partir de estos materiales, en especial la vía química, cuya perspectiva de éxito se encuentra estrechamente vinculada al desarrollo de reactores continuos. De esta manera, se pueden intensificar las condiciones de reacción que permitan incrementar la productividad del proceso, mediante la obtención de los máximos rendimientos de azúcares con el empleo de los menores volúmenes del equipamiento, sin descuidar la disminución de la concentración de sustancias inhibidoras de la fermentación en el sistema.

  4. A VoIP Privacy Mechanism and its Application in VoIP Peering for Voice Service Provider Topology and Identity Hiding

    CERN Document Server

    Shen, Charles

    2008-01-01

    Voice Service Providers (VSPs) participating in VoIP peering frequently want to withhold their identity and related privacy-sensitive information from other parties during the VoIP communication. A number of existing documents on VoIP privacy exist, but most of them focus on end user privacy. By summarizing and extending existing work, we present a unified privacy mechanism for both VoIP users and service providers. We also show a case study on how VSPs can use this mechanism for identity and topology hiding in VoIP peering.

  5. Electronic structure and insulating gap in epitaxial VO2 polymorphs

    Directory of Open Access Journals (Sweden)

    Shinbuhm Lee

    2015-12-01

    Full Text Available Determining the origin of the insulating gap in the monoclinic V O2(M1 is a long-standing issue. The difficulty of this study arises from the simultaneous occurrence of structural and electronic transitions upon thermal cycling. Here, we compare the electronic structure of the M1 phase with that of single crystalline insulating V O2(A and V O2(B thin films to better understand the insulating phase of VO2. As these A and B phases do not undergo a structural transition upon thermal cycling, we comparatively study the origin of the gap opening in the insulating VO2 phases. By x-ray absorption and optical spectroscopy, we find that the shift of unoccupied t2g orbitals away from the Fermi level is a common feature, which plays an important role for the insulating behavior in VO2 polymorphs. The distinct splitting of the half-filled t2g orbital is observed only in the M1 phase, widening the bandgap up to ∼0.6 eV. Our approach of comparing all three insulating VO2 phases provides insight into a better understanding of the electronic structure and the origin of the insulating gap in VO2.

  6. Biology of VO2 max: looking under the physiology lamp.

    Science.gov (United States)

    Lundby, C; Montero, D; Joyner, M

    2016-11-07

    In this review, we argue that several key features of maximal oxygen uptake (VO2 max) should underpin discussions about the biological and reductionist determinants of its interindividual variability: (i) training-induced increases in VO2 max are largely facilitated by expansion of red blood cell volume and an associated improvement in stroke volume, which also adapts independent of changes in red blood cell volume. These general concepts are also informed by cross-sectional studies in athletes that have very high values for VO2 max. Therefore, (ii) variations in VO2 max improvements with exercise training are also likely related to variations in these physiological determinants. (iii) All previously untrained individuals will respond to endurance exercise training in terms of improvements in VO2 max provided the stimulus exceeds a certain volume and/or intensity. Thus, genetic analysis and/or reductionist studies performed to understand or predict such variations might focus specifically on DNA variants or other molecular phenomena of relevance to these physiological pathways.

  7. Proposal of Secure VoIP System Using Attribute Certificate

    Science.gov (United States)

    Kim, Jin-Mook; Jeong, Young-Ae; Hong, Seong-Sik

    VoIP is a service that changes the analogue audio signal into a digital signal and then transfers the audio information to the users after configuring it as a packet; and it has an advantage of lower price than the existing voice call service and better extensibility. However, VoIP service has a system structure that, compared to the existing PSTN (Public Switched Telephone Network), has poor call quality and is vulnerable in the security aspect. To make up these problems, TLS service was introduced to enhance the security. In practical system, however, since QoS problem occurs, it is necessary to develop the VoIP security system that can satisfy QoS at the same time in the security aspect. In this paper, a user authentication VoIP system that can provide a service according to the security and the user through providing a differential service according to the approach of the users by adding AA server at the step of configuring the existing VoIP session is suggested. It was found that the proposed system of this study provides a quicker QoS than the TLS-added system at a similar level of security. Also, it is able to provide a variety of additional services by the different users.

  8. Structural characterization of PrVO3 epitaxial thin films

    CERN Document Server

    Copie, O; Boullay, P; Morales, M; Pautrat, A; David, A; Mercey, B; Pravarthana, D; Infante, I C; Janolin, P -E; Prellier, W

    2014-01-01

    Rare earth perovskite oxides constitute a wide family of materials presenting functional proper- ties strongly coupled to their crystalline structure. Here, we report on the experimental results on epitaxial PrVO3 deposited on SrTiO3 single crystal substrates by pulsed laser deposition. By com- bining advanced structural characterization tools, we have observed that the PVO unrelaxed film structure grown on STO, is characterized by two kinds of oriented domains whose epitaxial relations are: (i) PrVO3[110]o//SrTiO3[001]c and PrVO3[001]o//SrTiO3[100]c, (ii) PrVO3[110]o//SrTiO3[001]c and PrVO3[001]o//SrTiO3[010]c. We have also measured reciprocal space maps. From these results, we have determined that the PVO film epitaxy on STO imposes a lowering of the PVO structure symmetry from orthorhombic (Pbnm) to monoclinic (P21/m). We show, the nominal strain induced by the substrate being constant, that the obtained film structure depends on both growth oxygen and temperature. Thus, by finely controlling the depositio...

  9. Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition

    Science.gov (United States)

    Mathevula, L.; Ngom, B. D.; Kotsedi, L.; Sechogela, P.; Doyle, T. B.; Ghouti, M.; Maaza, M.

    2014-09-01

    VO2 thin films have been deposited by pulsed laser deposition on Zinnwaldite Mica substrates. The crystal structure, chemical composition, morphology were determined and the semiconductor/metal transition (SMT) properties of the deposited films were investigated. Without any post annealing, the films exhibit a textured nature with a VO2 (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio RS/RM through the SMT at T ≈ 68 °C of the order of 104 and a narrow ∼7 °C hysteresis. In addition, the growth of the VO2 crystallites seem to be governed likely by a Volmer-Weber or Stranski-Krastanov mechanisms and certainly not a Frank-van Der Merwe process.

  10. A VO-driven Astronomical Data Grid in China

    CERN Document Server

    Cui, Chenzhou; Yang, Yang; Zhao, Yongheng

    2010-01-01

    With the implementation of many ambitious observation projects, including LAMOST, FAST, and Antarctic observatory at Doom A, observational astronomy in China is stepping into a brand new era with emerging data avalanche. In the era of e-Science, both these ambitious projects and traditional astronomy research need much powerful data management, sharing and interoperability. Based on data-grid concept, taking advantages of IVOA interoperability technologies, China-VO is developing a VO-driven astronomical data grid environment to enable multi-wavelength science and large database science. In the paper, latest progress and data flow of the LAMOST, architecture of the data grid, and its supports to the VO are discussed.

  11. The NOAO NVO Portal: Client-Side VO

    Science.gov (United States)

    Gasson, D.; Fuentes, E.; Miller, C. J.

    2007-10-01

    The NOAO National Virtual Observatory (NVO) portal is a recently deployed web application for one-stop discovery, analysis, and access to VO-compliant imaging data and services. The NOAO NVO portal utilizes Simple Image Access Protocol (SIAP) services provided by some astronomical archives. The portal also utilizes a number of SOAP-based VO web services (WESIX, Sesame, etc). We discuss the design decisions and technology choices that were made in the NOAO NVO portal code to facilitate the use of IVOA standards and VO data/services. This includes a new Virtual Observatory library written for Ruby: an interpreted scripting language for quick and easy object-oriented programming. We provide an overview of VORuby and how it is utilized in the NOAO NVO Portal.

  12. VoLTE异厂家组网方案研究%VoLTE Different Manufacturers Network Scheme

    Institute of Scientific and Technical Information of China (English)

    杨健; 于富东

    2016-01-01

    VoLTE是LTE(Long Term Evolution)语音业务的目标方案,需要IMS(IP Multimedia Subsystem)系统提供业务支撑,VoLTE核心网的单厂家组网方案,短时期内满足了呼叫业务的端到端测试,但也容易受单个厂家的技术限制.从现有VoLTE单厂家单域组网的实际情况出发,分析IMS核心网网元异厂家设备间组网方案的可行性,并提出多种组网方案的分析和建议.综合无线系统、HSS/HLR(Home Subscriber Server/Home Location Register)、分组域等因素的影响,分业务区引入不同厂家VoLTE IMS设备组网,在控制网络建设投资的前提下,既能保证新技术和新业务的快速上线,也能为网络的安全性、扩展性带来保障.对VoLTE的扩大部署及各运营商的实际网络建设提供指导意见.

  13. VO2 Reserve vs. Heart Rate Reserve During Moderate Intensity Treadmill Exercise.

    Science.gov (United States)

    Solheim, Tanner J; Keller, Brad G; Fountaine, Charles J

    VO2 and heart rate (HR) are widely used when determining appropriate training intensities for clinical, healthy, and athletic populations. It has been shown that if the % reserve (%R) is used, rather than % of max, HR and VO2 can be used interchangeably to accurately prescribe exercise intensities. Thus, heart rate reserve (HRR) can be prescribed if VO2 reserve (VO2R) is known. Therefore, the purpose of this study was to compare VO2 R and HRR during moderate intensity exercise (50%R). Physically active college students performed a maximal treadmill test to exhaustion. During which VO2 and HR were monitored to determine max values. Upon completion of the maximal test, calculations were made to determine the % grade expected to yield approximately 50% of the subjects VO2R. Subjects then returned to complete the submaximal test (50%R) at least two days later. The %VO2R and %HRR were calculated and compared to the predicted value as well as to each other. Statistical analysis revealed that VO2 at 50%R was significantly greater than the actual VO2 achieved, p VO2 could be more accurately predicted than HR during moderate intensity exercise. The weak correlation between VO2R and HRR indicates that caution should be used when relying on a HR to determine VO2.

  14. Providing VoD Streaming Using P2P Networks

    Science.gov (United States)

    Pedro Muñoz-Gea, Juan; Malgosa-Sanahuja, Josemaria; Manzanares-Lopez, Pilar; Carlos Sanchez-Aarnoutse, Juan

    Overlays and P2P systems, initially developed to support IP multicast and file-sharing, have moved beyond that functionality. They are also proving to be key technologies for the delivery of video streaming. Recently, there have been a number of successful deployments for "live" P2P streaming. However, the question remains open whether similar P2P technologies can be used to provide VoD (Video-On-Demand) services. A P2P VoD service is more challenging to design than a P2P live streaming system because the system should allow users arriving at arbitrary times to watch (arbitrary parts of) the video.

  15. Update of the China-VO AstroCloud

    CERN Document Server

    Cui, Chenzhou; Xiao, Jian; He, Boliang; Li, Changhua; Fan, Dongwei; Wang, Chuanjun; Hong, Zhi; Li, Shanshan; Mi, Linying; Wan, Wanghui; Cao, Zihuang; Wang, Jiawei; Yin, Shucheng; Fan, Yufeng; Wang, Jianguo; Yang, Sisi; Ling, Yin; Zhang, Hailong; Chen, Junyi; Liu, Liang; Chen, Xiao

    2016-01-01

    As the cyber-infrastructure for Astronomical research from Chinese Virtual Observatory (China-VO) project, AstroCloud has been archived solid progresses during the last one year. Proposal management system and data access system are re-designed. Several new sub-systems are developed, including China-VO PaperData, AstroCloud Statics and Public channel. More data sets and application environments are integrated into the platform. LAMOST DR1, the largest astronomical spectrum archive was released to the public using the platform. The latest progresses will be introduced.

  16. UTN VoIP test bed (Voice over Internet Protocol)

    OpenAIRE

    Clérigo, Patricia; Mercado, Gustavo; Lima, Armando; Gosetto, Gerardo

    2009-01-01

    La tecnología Voice over IP permite transmitir paquetes de voz usando los protocolos de Internet. Esto es el basamento de la convergencia de video, voz y datos en una sola red y bajo el mismo protocolo; metodología que promete confiabilidad, accesibilidad y por sobre todo bajos costos. La UTN VoIP es un servicio de Telefonía que usa los protocolos VoIP de Internet y es montado sobre la Red Universitaria Tecnológica II. Cuando esté implementada conectará todas las Facultades Regionales y la Un...

  17. Preparation and crystal structure of a new bismuth vanadate, Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, N., E-mail: kumada@yamanashi.ac.jp [Department of Research Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Miyamae-cho 7-32, Kofu 400-8511 Japan (Japan); Takei, T.; Haramoto, R.; Yonesaki, Y.; Dong, Q.; Kinomura, N. [Department of Research Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Miyamae-cho 7-32, Kofu 400-8511 Japan (Japan); Nishimoto, S.; Kameshima, Y.; Miyake, M. [Department of Material and Energy Science, Graduate School of Environmental Science, Okayama University, Tsusima-Naka 3-3-1, Okayama 700-8530 Japan (Japan)

    2011-06-15

    Graphical abstract: Crystal structure of Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2}. Solid lines indicate the unit cell. Highlights: {yields} We can prepare a new bismuth vanadate, Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2} by hydrothermal reaction using a hydrated sodium bismuthate. {yields} We clarify that the crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO{sub 4} tetrahedra. {yields} This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation. -- Abstract: Single crystals of a new bismuth vanadate, Bi{sub 3.33}(VO{sub 4}){sub 2}O{sub 2} was prepared by hydrothermal reaction using a hydrated sodium bismuthate, NaBiO{sub 3}.nH{sub 2}O as one of the starting compounds. The crystal structure was determined by using single crystal X-ray diffraction data. This compound crystallizes in the triclinic space group P1{sup -bar} (no. 2) with a = 7.114(1), b = 7.844(2), c = 9.372(2) A, {alpha} = 106.090(7), {beta} = 94.468(7) and {gamma} = 112.506(8){sup o}, Z = 2 and the final R factors are R1 = 0.052 and wR2 = 0.14 for 2085 unique reflections. The crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO{sub 4} tetrahedra, and one of four bismuth atoms is statistically distributed in the splitting sites with the distance of 0.83 A. This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation and its activity was less than that of monoclinic BiVO{sub 4}.

  18. Effect of butyrate on aromatase cytochrome P450 levels in HT29, DLD-1 and LoVo colon cancer cells.

    Science.gov (United States)

    Rawłuszko, Agnieszka Anna; Sławek, Sylwia; Gollogly, Armin; Szkudelska, Katarzyna; Jagodziński, Paweł Piotr

    2012-03-01

    Epidemiological studies suggest that colonic production of butyrate and estrogen may be involved in human susceptibility to colorectal cancer (CRC). Estrone (E1) can be produced by the aromatase pathway during the conversion of androstenedione (A) to E1. Therefore, we studied the effect of sodium butyrate (NaBu) on the CYP19A1 transcript and protein levels and on the conversion of A to E1 in HT29, DLD-1 and LoVo CRC cells. We found that NaBu significantly downregulated CYP19A1 transcript and protein levels, a phenomenon that was associated with reduced conversion of A to E1 in HT29, DLD-1 and LoVo cells. Our studies demonstrated that, although butyrate exhibited a protective role in CRC development, this compound may reduce aromatase activity and the production of E1 in colon cancer cells.

  19. VoIP Leads the Revolution of Enterprise Communication%VoIP引领企业通信革命

    Institute of Scientific and Technical Information of China (English)

    殷康

    2005-01-01

    20年前,有谁能想到互联网会对人类社会产生如此深远的影响?今天网络也能“说”会“道”。Skype瞬间风靡全球,Google.com、AT&T、YahooBB也在企图迎合VoIP带来的沟通方式革命。互联网终端的普及带来了IP化通信,也催生了VoIP应用的热潮。当目前媒体和公众舆论集中于大众VoIP热潮的时候,实际上,新一轮企业通信革命在企业网络之中正悄悄地进行。

  20. 无线通信环境下VoIP的应用%VoIP Application in Wireless Environment

    Institute of Scientific and Technical Information of China (English)

    李明; 吴燕玲

    2006-01-01

    目前,随着无线通信技术GPRS(General Packet Radio Service)和IEEE802.11 WLAN(WirelessLocal Area Networks)的应用越来越普及,如何将VoIP和无线通信技术有效地结合起来成为了下一代的无线网络的研究方向了.阐述了在无线广域网和无线局域网上VoIP的应用,并且展望了下一代的互连网协议IPv6在VoIP中的应用.

  1. Data of evolutionary structure change: 1CPDA-2VO2X [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1CPDA-2VO2X 1CPD 2VO2 A X LVHVASVEKGRSYEDFQK---VYNAIALKLREDDEYDNY...IGYGPVLVRLAWHISGTWDKHDNTGGSYGGTYRFKKEFNDPSNAGLQNGFKFLEPIHKEFPWISSGDLFSLGGVTAVQEMQGPKIPWRCGRVDTPEDTTPDNGRLPDA...GFIAEKR-------CAPLMLRLAAHSAGTFDKGTKTGGPF-GTIKHPAELAHSANNGLDIAVRLLEPLKAEFPILSYADFYQLAGVVAVEVTGGPEVPFHPGREDKP--EPPPEGRLPDA...ID> 0 1CPD A 1CPDA 1 1CPD A 1CPDA

  2. Optimización del medio de cultivo QBP para la producción de biomasa del consorcio BIOYAF

    Directory of Open Access Journals (Sweden)

    Yaima Barrios San Martín

    2014-06-01

    Full Text Available Título en inglés: Optimization of culture media QBP to the production of biomass of consortium BIOYAF Título corto: Optimización de un medio de cultivoResumen: La optimización de los medios de cultivo con fines industriales en la mayoría de los casos ha sido efectuada mediante procedimientos empíricos de ensayo y error. Empleando diversos métodos estadísticos es probable que el medio de cultivo original pueda ser optimizado, en muchos casos es posible obtener un medio que no solo sea más productivo, sino de menor o igual costo que el original. Se optimizó el medio de cultivo QBP para el crecimiento de las cepas del consorcio bacteriano BIOYAF capaz de degradar hidrocarburos del petróleo, empleando un Diseño de Factor Categórico Individual para determinar el tiempo de trabajo, un Diseño Factorial (24 para determinar los rangos de trabajo de concentración de los nutrientes y un Diseño de Superficie de Respuesta para optimizar las concentraciones. Las variables de respuesta de evaluación de los experimentos fueron masa húmeda, masa (UDO, conteo de viables, conductividad, pH y tensión superficial. El tiempo óptimo para el crecimiento de las cepas del consorcio BIOYAF es de seis horas. El medio de cultivo QBP con concentraciones óptimas de fosfato de amonio (3,19 g.l-1, sulfato de magnesio (0,04 g.l-1, levadura (3,77 g.l-1 y sacarosa (47,89 g.l-1 permite que la producción de biomasa aumente de 1,540 UDO a 3,082 UDO.Palabras clave: superficie de respuesta, consorcio bacteriano, crecimiento óptimo.Abstract: The optimization of culture media with industrial purposes, in most cases, has been made through empirical trial and error procedures. Using different statistical methods original culture media can be optimized, in many cases, it is possible to obtain a more productive media, at the same cost as the original one. The culture media QBP was optimized for the growth of the bacterial consortium BIOYAF, which can degrade

  3. Desarrollo de una tecnología para la producción a pequeña escala de la biomasa del hongo ostra (Pleurotus ostreatus)

    OpenAIRE

    2014-01-01

    En este trabajo se presenta el diseño tecnológico de una planta para la producción a pequeña escala de biomasa del hongo ostra (Pleurotus ostreatus) donde se introduce la modelaicón matemática en la etapa de fermentación. Se seleccionó la cepa ceba-gliie-po-010106 de P. ostreatus, asilada de la Sierra Norte ecuatoriana, la que presenta una velocidad promedio de crecimiento igual a 0.584 mm/h en un medio rico. El residuo de fréjol aportó los mejores resultados, con una bioconversión promedio d...

  4. HIDRÓLISIS ÁCIDA DE CELULOSA Y BIOMASA LIGNOCELULÓSICA ASISTIDA CON LÍQUIDOS IÓNICOS

    OpenAIRE

    Silvia Morales de la Rosa

    2015-01-01

    Los procesos de hidrólisis de biomasa lignocelulósica suelen utilizar enzimas para romper las moléculas de polisacáridos y producir azucares. Junto con la optimización y mejora de los procesos de hidrólisis enzimática, existe también gran interés en el desarrollo de vías alternativas de transformación mediante procesos de hidrólisis química. Uno de los cuellos de botella más importantes de comercialización de bioetanol lignocelulósico es el descubrimiento de una hidrólisis rentable de la celu...

  5. Modelado y simulación del proceso de pirolisis rápida de biomasa en un reactor de lecho fluidizado

    OpenAIRE

    Blanco Leal, Luz Adriana

    2014-01-01

    Resumen: En este trabajo se desarrolló un modelo matemático de base fenomenológica para el proceso de pirólisis rápida de biomasa en lecho fluidizado burbujeante. El modelo fue desarrollado en estado transitorio, es unidimensional y está basado en la teoría de las dos fases. Se empleó un mecanismo de reacción semi-global en dos etapas considerando la formación primaria de productos y las reacciones secundarias de los vapores. Además, se plantearon balances de población para la distribución d...

  6. Componente lento do VO2 em crianças durante exercício pesado de corrida: análise com base em diferentes modelos matemáticos Componente lento de VO2 en niños durante ejercicio arduo de carrera: análisis con base en diferentes modelos matemáticos Slow component of VO2 in children during running exercise performed at heavy intensity domain: analysis with different mathematical models

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2006-12-01

    Full Text Available O objetivo deste estudo foi verificar e quantificar a magnitude do componente lento do consumo de oxigênio (CL em crianças submetidas a exercícios de corrida em esteira rolante, com cargas constantes de intensidade acima do limiar de lactato (75%D, utilizando para isso dois modelos de análise: a modelo matemático com três termos exponenciais; e b modelo deltaVO2 6-3min. Participaram do estudo oito crianças do sexo masculino (11,92 ± 0,63 anos; 44,06 ± 13,01kg; 146,63 ± 7,25cm; e níveis de maturação sexual 1 e 2, aparentemente saudáveis, não treinadas, que realizaram em diferentes dias: 1 teste incremental na esteira rolante para a determinação do consumo de oxigênio de pico (VO2pico e do limiar de lactato (LL; e 2 dois testes de carga constante em esteira rolante durante seis minutos na intensidade de 75%delta [75%delta = LL + 0,75 x (VO2pico - LL]. Para determinação do CL utilizaram-se: a modelo matemático de três termos (Exp3; e b a diferença no VO2 entre o sexto e o terceiro minuto de exercício (deltaVO2 6-3min. O CL foi expresso em valores absolutos (ml/min e também como a contribuição percentual do CL para o aumento do VO2 no final do exercício (%CL. O CL determinado pelo modelo Exp3 (129,69 ± 75,71ml/min e 8,4 ± 2,92% foi significantemente maior do que o obtido pelo modelo deltaVO2 6-3min (68,69 ± 102,54ml/min e 3,6 ± 7,34%. Portanto, os valores de CL obtidos em crianças durante o exercício de corrida realizado no domínio pesado (75%delta são dependentes do modelo de análise (Exp3 x deltaVO2 6-3min.El objetivo de este estudio ha sido el de verificar y cuantificar la magnitud del componente lento del consumo de oxígeno (CL en niños, sometidos a ejercicios de carrera en cinta rodante, con cargas constantes de intensidad por encima del límite de lactato (75%delta, utilizando para esto dos modelos de análisis: a modelo matemático con tres términos exponenciales; y b modelo deltaVO2 6-3 min

  7. Mediated proton transport through Nafion 117 membranes imbibed with varying concentrations of aqueous VOSO4 (VO2+) and NH4VO3 (VO2+) in 2 M H2SO4

    Science.gov (United States)

    Suarez, Sophia; Paterno, Domenec

    2016-11-01

    We performed an extensive study on Nafion 117 membrane imbibed with various concentrations of aqueous ammonium metavanadate (NH4VO3), and vanadyl sulfate (VOSO4), in 2 M H2SO4 over the temperature range of 20-100 °C, using 1H NMR and AC Impedance spectroscopies. The objective was to determine the effect of the tetravalent (VO2+) and pentavalent (VO2+) vanadium ions on the proton transport of Nafion 117.1H NMR chemical shift and linewidth data show greater short-range proton transport for the VO2+ imbibed membranes compared with the VO2+. However, the local environments seem to differ in that while the data for VO2+ imbibed membranes seem to follow more the trends observed for water hydrated Nafion 117, those for the VO2+ followed the trend of its aqueous bulk vanadium solvents, indicating that viscosity plays a larger role for the VO2+ imbibed membranes compared to the VO2+.

  8. Efecto de la depuración en la biomasa del caracol Pomacea patula [Baker, 1922] usando el índice de condición

    Directory of Open Access Journals (Sweden)

    M. García-Ulloa

    2006-01-01

    Full Text Available La depuración de organismos acuáticos en cultivo es una práctica común. El tiempo de exposición de los animales al agua tratada es uno de los factores más importantes para su eficiencia, pudiendo afectar su biomasa. Se evaluó el efecto de la depuración en adultos de Pomacea patula mediante la aplicación del índice de condición (IC, bajo condiciones de laboratorio. Caracoles adultos obtenidos en cultivo se mantuvieron en peceras (Grupo 1 expuestos a un flujo de agua constante, tratada con radiación ultravioleta y limpieza diaria y en condiciones normales de mantenimiento (Grupo 2, con 5 réplicas por grupo. Se obtuvo el peso húmedo y longitud total individualmente, al inicio y después de una depuración de 10 días. El valor promedio del coeficiente de correlación (animales iniciales y de los Grupos 1 y 2 fue mayor a 0.90. El IC entre el valor inicial (771.81 ± 40.41 y los Grupos 1 y 2 (763.527 ± 25.24 y 765.465 ± 38.59, respectivamente, no mostró diferencias significativas (P > 0.05 al final del experimento. Los resultados sugieren que el proceso de depuración usado no afectó la biomasa de adultos de P. patula. El IC se mostró como una herramienta práctica de evaluación sin considerar la diferencia inicial de tallas de caracoles adultos

  9. Efecto de lixiviados del raquis de plátano sobre la actividad y biomasa microbiana en floración y cosecha del tomate

    Directory of Open Access Journals (Sweden)

    Muñoz V. Rosa Elvira

    2005-03-01

    Full Text Available Se utilizaron cinco tratamientos: el testigo (T0 y cuatro concentraciones de lixiviados (T1= 100%, T2= 75%, T3= 50% y T4= 25% aplicados 15, 30 y 60 días después del trasplante. La actividad microbiana se determinó con la metodología del CAB y la biomasa microbiana con el método de fumigación-extracción. En la actividad microbiana se encontraron diferencias significativas entre los tratamientos, presentando la aplicación del lixiviado a la menor concentración (25% la mayor actividad (56.76 mgCO2g suelo-1. La actividad fue mayor en floración en todos los tratamientos. Para biomasa microbiana no se presentaron diferencias significativas entre los tratamientos ni entre épocas. ABSTRACT The effect of leaching from rachis on soil microbial biomass and activity during tomato flowering and harvesting period. Field trail comprised five treatments of different leaching concentrations (T0= test, T1= 100%, T2= 75%, T3=50%, and T4=25% sprinkled on soil 15, 30 and 60 days after tomato transplanting. Microbial activity was measured with CAB method and microbial biomass was recorded with fumigation - extraction method. The average microbial activity with sprinking of 25% of leaching was higher (56.76 mgCO2g suelo-1. No significant difference in order to treatments and periods in microbial biomass were observed. These observations showed leaching sprinkling in low concentration influence en microbial activity for the conditions of this experiment. Key words: Soil biology, biomass, leaching, Lycopersicum sculentun.

  10. Análisis Exergético de la Gasificación de Biomasa Exergy Analysis of Biomass Gasification

    Directory of Open Access Journals (Sweden)

    Jorge M Mendoza

    2012-01-01

    Full Text Available El objetivo de este estudio fue realizar el análisis exergético de la gasificación de biomasa residual con la finalidad de obtener energía útil. Se desarrolló un modelo para la gasificación de biomasa basado en el equilibrio químico de las reacciones. Este modelo permite predecir la evolución de la composición del gas de síntesis en función de la temperatura, las presiones y la composición elemental de los residuos del proceso de extracción de aceite de palma y orujo de lavado de uva (hidrogeno, oxigeno, carbono y nitrógeno, como también hacer un análisis exergético. Se encontró que independiente del agente gasificante, la concentración de monóxido de carbono e hidrógeno tienden a incrementar significativamente a altas presiones y elevadas temperaturas. Además, se muestra que la eficiencia exergética incrementa con la temperatura y disminuye con el aumento de la relación aire/combustible.This paper shows the exergy analysis applied to the gasification process of residual biomass with the purpose of obtaining useful energy. A model for the biomass gasification based on chemical equilibrium of the reactions is proposed. The model allows predicting the syngas composition as a function of temperature, pressure and ultimate analysis of palm oil and grapevine pruning waste (determining hydrogen, oxygen, carbon and nitrogen. It was found that the carbon monoxide and hydrogen concentration significantly increase at high pressure and temperature independently of the gasifying agent. Furthermore, it was also noticed that the exergy efficiency increases as temperature increases, and decreases as the relative fuel/air ratio increases.

  11. Estimation of VO2 Max: A Comparative Analysis of Five Exercise Tests.

    Science.gov (United States)

    Zwiren, Linda D.; And Others

    1991-01-01

    Thirty-eight healthy females measured maximal oxygen uptake (VO2max) on the cycle ergometer and treadmill to compare five exercise tests (run, walk, step, and two tests using heart-rate response on the bicycle ergometer) in predicting VO2max. Results indicate that walk and run tests are satisfactory predictors of VO2max in 30- to 39-year-old…

  12. File list: DNS.Dig.10.AllAg.LoVo [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Dig.10.AllAg.LoVo hg19 DNase-seq Digestive tract LoVo ERX306455,ERX306454,ERX30...6458,ERX306459,ERX306456,ERX306457 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Dig.10.AllAg.LoVo.bed ...

  13. Covert Channels in SIP for VoIP Signalling

    Science.gov (United States)

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for typical IP telephony call.

  14. Covert Channels in SIP for VoIP signalling

    CERN Document Server

    Mazurczyk, Wojciech

    2008-01-01

    In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for typical IP telephony call.

  15. Bulk and electrochemical properties of BiVO4

    NARCIS (Netherlands)

    Vinke, I.C.; Diepgrond, J.; Boukamp, B.A.; Vries, de K.J.; Burggraaf, A.J.

    1992-01-01

    The mixed (oxygen ionic-electronic) conductor bismuth vanadate (BiVO4) was studied with respect to its electrochemical properties. The ionic transference numbers, measured by the concentration cell method in the temperature range of 800 to 1000 K, vary from 0.7 to 0.3. The total conductivity of this

  16. Matching of Male and Female Subjects Using VO2 Max.

    Science.gov (United States)

    Cureton, Kirk J.

    1981-01-01

    The increasing use of various VO2 max expressions as test measures is a problem because the magnitude of sex difference varies considerably with each expression. A valid match of male and female test subjects would consider physical activity history and the amount of endurance exercise done in the previous year. (Author/FG)

  17. Validity of 3 protocols for verifying VO2 max.

    Science.gov (United States)

    Kirkeberg, J M; Dalleck, L C; Kamphoff, C S; Pettitt, R W

    2011-04-01

    The verification bout has emerged as a technique for confirming 'true' VO2 max; however, validity during a single visit is unknown. We evaluated 3 different GXT durations with severe intensity verification bouts. On 3 separate days, in counterbalanced order, 12 recreational-trained men completed short (9±1 min), middle (11±1 min), and long (13±2 min) duration GXTs followed by exhaustive, sine wave verification bouts during the same visit. Intensities for verification were set at speeds equivalent to 2-stages minus end-GXT speed. No differences (pVO2 max (mL/kg/min) were observed between short (49.1), middle (48.2), and long (48.8) protocols. In addition, no differences in verification bout duration occurred between protocols (3±1 min). Validity of VO2 max was strongest for the middle duration protocol (ICC α=0.97; typical error=1 mL/kg/min; CV=2%). A small, but significantly higher HR (max) (∼1-2 bpm) was observed for the long protocol. Maximum respiratory exchange ratios were inconsistent (ICC α ranged 0.58-0.68). Our findings indicate GXT-verification bout testing during a single visit is a valid means of measuring 'true' VO2 max. The 10 min target for GXT duration was the optimum.

  18. VO2 prediction and cardiorespiratory responses during underwater treadmill exercise.

    Science.gov (United States)

    Greene, Nicholas P; Greene, Elizabeth S; Carbuhn, Aaron F; Green, John S; Crouse, Stephen F

    2011-06-01

    We compared cardiorespiratory responses to exercise on an underwater treadmill (UTM) and land treadmill (LTM) and derived an equation to estimate oxygen consumption (VO2) during UTM exercise. Fifty-five men and women completed one LTM and five UTM exercise sessions on separate days. The UTM sessions consisted of chest-deep immersion, with 0, 25, 50, 75, and 100% water-jet resistance. All session treadmill velocities increased every 3 min from 53.6 to 187.8 m x min(-1). Cardiorespiratory responses were similar between LTM and UTM when jet resistance for UTM was 50%. Using multiple regression analysis, weight-relative VO2 could be estimated as: VO2 (mLO2 c kg(-1) x min(-1)) = 0.19248 x height (cm) + 0.17422 x jet resistance (% max) + 0.14092 x velocity (m x min(-1)) -0.12794 x weight (kg)-27.82849, R2 = .82. Our data indicate that similar LTM and UTM cardiorespiratory responses are achievable, and we provide a reasonable estimate of UTM VO2.

  19. Visible light driven photocatalysis and antibacterial activity of AgVO{sub 3} and Ag/AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anamika [Department of Life Sciences, University of Mumbai, Santacruz (E), Mumbai 400 098 (India); Dutta, Dimple P., E-mail: dimpled@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Ballal, A. [Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Fulekar, M.H. [School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar 382 030, Gujarat (India)

    2014-03-01

    Graphical abstract: - Highlights: • Ag/AgVO{sub 3} and pure AgVO{sub 3} nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO{sub 3} within 45 min. • Antibacterial activity of Ag/AgVO{sub 3} demonstrated. - Abstract: Ag/AgVO{sub 3} nanowires and AgVO{sub 3} nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO{sub 3} nanowires. The photocatalytic studies revealed that the Ag/AgVO{sub 3} nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO{sub 3} nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the β-AgVO{sub 3} nanorods prove that in case of the Ag dispersed Ag/AgVO{sub 3} nanowires, the enhanced antibacterial action is also due to contribution from the AgVO{sub 3} support.

  20. Identifying the active site in nitrogen-doped graphene for the VO2+/VO2(+) redox reaction.

    Science.gov (United States)

    Jin, Jutao; Fu, Xiaogang; Liu, Qiao; Liu, Yanru; Wei, Zhiyang; Niu, Kexing; Zhang, Junyan

    2013-06-25

    Nitrogen-doped graphene sheets (NGS), synthesized by annealing graphite oxide (GO) with urea at 700-1050 °C, were studied as positive electrodes in a vanadium redox flow battery. The NGS, in particular annealed at 900 °C, exhibited excellent catalytic performance in terms of electron transfer (ET) resistance (4.74 ± 0.51 and 7.27 ± 0.42 Ω for the anodic process and cathodic process, respectively) and reversibility (ΔE = 100 mV, Ipa/Ipc = 1.38 at a scan rate of 50 mV s(-1)). Detailed research confirms that not the nitrogen doping level but the nitrogen type in the graphene sheets determines the catalytic activity. Among four types of nitrogen species doped into the graphene lattice including pyridinic-N, pyrrolic-N, quaternary nitrogen, and oxidic-N, quaternary nitrogen is verified as a catalytic active center for the [VO](2+)/[VO2](+) couple reaction. A mechanism is proposed to explain the electrocatalytic performance of NGS for the [VO](2+)/[VO2](+) couple reaction. The possible formation of a N-V transitional bonding state, which facilitates the ET between the outer electrode and reactant ions, is a key step for its high catalytic activity.

  1. Similar foliage area but contrasting foliage biomass between young beech and spruce stands / Porovnateľná plocha avšak kontrastná biomasa asimilačných orgánov medzi mladými porastmi buka a smreka

    Directory of Open Access Journals (Sweden)

    Konôpka Bohdan

    2014-12-01

    Full Text Available Výskum sa zameral na mladé porasty buka lesného (Fagus sylvatica a smreka obyčajného (Picea abies rovnakého veku (12 rokov, veľmi podobných dimenzií stromov, rastúcich na totožnom stanovišti. Na základe odberu vzorníkov celých stromov (všetky časti okrem jemných koreňov sme skonštruovali alometrické vzťahy pre stromové komponenty. Ako nezávislá premenná sa použila hrúbka na báze kmeňa (d0. Modely vyjadrili nielen biomasu konárov, kmeňa, hrubých koreňov a asimilačných orgánov, ale aj plochu asimilačných orgánov a špecifickú listovú plochu (specific leaf area; SLA. Zistili sme, že základné morfologické vlastnosti asimilačných orgánov varírovali pri obidvoch drevinách pozdĺž vertikálneho profilu koruny. V prípade smreka sa zistili odlišné hodnoty plochy ihlíc a SLA medzi jednotlivými ročníkmi ihlíc. Na úrovni stromu mali buky oveľa viac biomasy drevných častí ako smreky, opačná situácia bola pri asimilačných orgánoch. Preto hodnoty podielu medzi biomasou asimilačných orgánov a celkovou biomasou stromu, ako aj pomeru medzi plochou asimilačných orgánov a celkovou biomasou stromu boli výrazne vyššie pri smreku než buku. Na úrovni porastu mala smrečina vyššie hodnoty indexu listovej plochy, t. j. LAI (18,64 m2.m−2 v porovnaní s bučinou (12,77 m2.m−2. Kým biomasa asimilačných orgánov bola 4,6-krát väčšia v smrekovom než v bukovom poraste, biomasa drevných časti bola porovnateľná v obidvoch porastoch. Tieto kontrasty naznačujú výrazne odlišnú rastovú stratégiu, resp. alokáciu biomasy medzi bučinami a smrečinami v mladých štádiách

  2. 基于IMS的VoLTE计费研究%Research on IMS Based on VoLTE Charging

    Institute of Scientific and Technical Information of China (English)

    赵文贤; 黄琳; 马千里

    2015-01-01

    基于IMS的VoLTE(Voice over LTE)语音解决方案,已成为业界公认的LTE网络语音解决方案的主要发展方向。该方案可在实现LTE网络下提供高质量的音视频通话的同时提供高速率的数据业务。对基于IMS的VoLTE语音计费时如何实现IMS域和EPC域计费的关联进行了研究,提出了根据IMS APN标识关联EPC网络和通过PCRF传递IMS计费标识与P-GW计费标识进行关联的2种方法,从而使VoLTE语音产生的流量不进行计费;对当VoLTE语音发生SRVCC切换时如何避免IMS域和CS域语音重复计费进行了研究,提出了根据STN-SR和related-ICID进行话单过滤的2种方法,从而过滤掉CS重复话单。%VoLTE solution based on IMS has become the main development direction of LTE VoIP solutions. The scheme can be realized in the LTE network to provide the high quality of audio and video cal s while provide high rate data business. It studies how to realize the correlation of IMS domain and EPC domain during voice based on IMS charging, provides two methods of associat-ing EPC network according to IMS APN identifier and through the PCRF IMS charging logo and P-GW identification for correla-tion, to avoid the charging of the traffic of VoLTE. It also studies how to avoid the IMS domain and CS domain voice repeat bil-ing when current voice SRVCC switching occurs, and put forward two methods on filtering bil according to the STN-SR and related-ICID, so as to filter out the repeated bil ed in CS.

  3. Enhanced charge separation and oxidation kinetics of BiVO4 photoanode by double layer structure

    Science.gov (United States)

    Yang, Lin; Xiong, Yuli; Dong, Hongmei; Peng, Huarong; Zhang, Yunhuai; Xiao, Peng

    2017-03-01

    Monoclinic bismuth vanadate (BiVO4) is a promising semiconductor for photoelectrochemical water splitting. Here, we developed a facile fabrication of BiVO4 double layer photoanode on the fluorine-doped tin oxide substrate by electrodeposition. The BiVO4 double layer photoanode is composed by a dense BiVO4 film as the inner layer and a nanoporous BiVO4 film as the outer layer. Compared to the BiVO4 single layer photoanode, the optimized BiVO4 double layer photoanode produced a much higher photocurrent of 1.15 mA/cm2 at 0.6 V vs. Ag/AgCl under AM 1.5G (100 mW/cm2) illumination. The results of the photoelectric conversion kinetics for different samples revealed that the charge separation and oxidation kinetics efficiencies for the BiVO4 double layer are 47.2% and 51.6% at 0.6 V vs. Ag/AgCl, while the values for BiVO4 single layer are 32.3% and 35.8%, respectively. The improved photoelectrochemical performance for BiVO4 double layer is mainly ascribed to the decrease of defect state at the interface after inserting a dense BiVO4 as an inner layer to prevent the recombination of photogenerated electron-hole pairs.

  4. Bioadsorción de Cromo (VI en Solución Acuosa por la Biomasa Celular de Cryptococcus neoformans y Helminthosporium sp Biosorption of Chromium (VI from Aqueous Solutions by Fungal Biomass of Cryptococcus neoformans and Helminthosporium sp

    Directory of Open Access Journals (Sweden)

    I. Acosta

    2005-01-01

    Full Text Available Se determinó la bioadsorción de Cromo (VI en solución por la biomasa celular de la levadura capsulada Cryptococcus neoformans y del hongo micelial Helminthosporium sp, por el método colorimétrico de la difenilcarbazida. La biomasa de C. neoformans fue más eficiente en la remoción de Cromo (VI en solución (98% que la de Helminthosporium sp (65%. La mayor bioadsorción para C. neoformans fue a pH=2.0 +/- 0.2, mientras que para Helminthosporium sp fue a pH=4.0 +/- 0.2, ambas a 28oC durante 24 horas con 0.2 mg/L de biomasa celular. Se concluye que las biomasas fúngicas remueven eficientemente Cromo (VI en solución y pueden utilizarse para descontaminar nichos acuáticos contaminados con este metal.A determination was made on the biosorption of dissolved Chromium (VI using cellular biomass of the encapsulated yeast Cryptococcus neoformans and the mycelial fungus Helminthosporium sp. using a diphenylcarbazide colorimetric method. The C. neoformans biomass was more efficient in removing Chromium (VI from solution (98% than the Helminthosporium sp. (65%. The highest biosorption for C. neoformans was at pH 2.0 + 0.02, while for Helminthosporium sp this occurred at pH 4.0 + 0.2 , both at 28°C for 24 h employing 0.2 mg/L of cellular biomass. It is concluded that the fungal biomasses efficiently removed Chromium (VI from solution and could be used for decontamination of aquatic habitats polluted with this metal.

  5. ESTUDIO CINÉTICO DEL PROCESO DE DEVOLATILIZACIÓN DE BIOMASA LIGNOCELULÓSICA MEDIANTE ANÁLISIS TERMOGRAVIMÉTRICO PARA TAMAÑOS DE PARTÍCULA DE 2 A 19 mm

    Directory of Open Access Journals (Sweden)

    ANDRÉS MELGAR

    2008-01-01

    Full Text Available Con el objetivo de proporcionar herramientas que mejoren el diseño de los sistemas de gasificación/combustión de biomasa, y los modelos cinético-químicos de dichos procesos, se presenta un estudio de la cinética química asociada al proceso de devolatilización de biomasa mediante pruebas de termogravimetría utilizando tamaños de partícula que varían de 2 a 19 mm, y tasas de calentamiento de 10, 15 y 20 K/min. El desarrollo de este trabajo se justifica debido a que no hay resultados disponibles en la bibliografía que estudien tamaños superiores a 1 mm. Mediante el ajuste de los puntos experimentales utilizando un modelo de primer orden se determinan los parámetros de las constantes cinéticas (forma de Arrhenius. El estudio muestra que la energía de activación es directamente proporcional a la tasa de calentamiento y al tamaño de partícula, se comprueba que el proceso de descomposición térmica de la biomasa se da a temperaturas más altas con el aumento del tamaño de las partículas, debido a la importancia que toman los procesos de transferencia calor y masa. Los parámetros cinéticos calculados pueden ser utilizados en los modelos dimensionales del proceso de gasificación-combustión de biomasa, considerando el tamaño de las partículas intrínseco en la cinética.

  6. Aprovechamiento de Biomasa Peletizada en el Sector Ladrillero en Bogotá-Colombia: Análisis Energético y Ambiental Use of Pelleted Biomass in the Brick Industry in Bogota-Colombia: Energy and Environmental Analysis

    Directory of Open Access Journals (Sweden)

    César A García-Ubaque

    2013-01-01

    Full Text Available En este estudio se compara el desempeño energético y ambiental del uso de combustibles a partir de dos tipos de biomasas peletizadas: residuos de madera, provenientes de podas y residuos de la producción de muebles, principalmente aserrín. La biomasa proveniente de residuos de madera es uno de los materiales más adecuados para utilizar como combustible alternativo. El sector ladrillero tiene una gran demanda energética para sus procesos de secado y cocción y el uso de combustibles alternativos a partir de biomasa permite obtener reducciones importantes en emisiones atmosféricas y no afecta las condiciones técnicas del proceso de producción de ladrillos. La biomasa con mejor desempeño, tanto en las variables energéticas como ambientales evaluadas, fue el aserrín.This study compared the energy and environmental performance of fuels from two types of pelleted biomass: wood waste from pruning and waste from furniture production, mainly sawdust. Wood residues biomass is one of the most suitable materials for using as an alternative fuel. The brick manufacture sector has a high energy demand for its drying and firing processes and the use of alternative fuels from biomass allows significant reductions in emissions and does not affect the technical conditions of the process of brick production. The biomass with better performance was sawdust, which presented the optimum energy and environmental variables.

  7. Bulk and electrochemical properties of BiVO[sub 4

    Energy Technology Data Exchange (ETDEWEB)

    Vinke, I.C.; Diepgrond, J.; Boukamp, B.A.; Vries, K.J. de; Burggraaf, A.J. (Lab. for Inorganic Chemistry, Materials Science and Catalysis, Univ. of Twente, Enschede (Netherlands))

    1992-09-01

    The mixed (oxygen ionic-electronic) conductor bismuth vanadate (BiVO[sub 4]) was studied with respect to its electrochemical properties. The ionic transference numbers, measured by the concentration cell method in the temperature range of 800 to 1000 K, vary from 0.7 to 0.3. The total conductivity of this ceramic material is one order of magnitude lower than found for cubic yttria-stabilized zirconia (YSZ). The activation enthalpy for the electronic conductivity is high (193 kJ/mol) compared to the ionic conductivity (71 kJ/mol). The P[sub O2] dependency of the conductivity data in combination with the Seebeck measurements showed electrons to be the majority charge carriers, indicating that BiVO[sub 4] is an n-type mixed conductor. (orig.).

  8. VoIP市场及应用面面观

    Institute of Scientific and Technical Information of China (English)

    科胜讯系统公司

    2004-01-01

    网络语音协议(Voice over Internet Protocol,VoIP)是一套可以利用网络协议(Internet Protocol)传递语音信号的技术。一般而言,语音信息的传送是利用不连续的数字封包,而非公众交换电话网络(public switched telephone network,PSTN)上传统的线路约定(circuit-committed)的通信协议方式。VoIP与网络电话(Internet telephony)最主要的优势在于减免支付像传统电话服务的长途通话费用。

  9. Structural and physical properties of BiVO3

    Science.gov (United States)

    Singh, M. P.; Razavi, F. S.

    2014-03-01

    We report the phase stabilization and properties of BiVO3 (BVO) thin films, grown on (001) SrTiO3 and LaAlO3, using the pulsed laser deposition technique. Bi and V are in 3+ oxidation states as measured by using x-ray photoelectrons spectroscopy. BVO exhibits a Curie-Weiss paramagnetic behaviour and about -26 K Weiss temperature. This demonstrates the presence of a strong correlation effect due to the spin fluctuation. Additionally, these films exhibit a semiconducting behaviour owing to the thermally activated conduction process. A plausible explanation of the observed properties is presented by comparing with the closely related LaVO3 and other orthovanadates.

  10. Structural and physical properties of BiVO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M. P., E-mail: mangala.singh@gmail.com; Razavi, F. S., E-mail: mangala.singh@gmail.com [Department of Physics, Brock University, 500 Glenridge Avenue, St Catharines, Ontario, L2S 3A1 (Canada)

    2014-03-31

    We report the phase stabilization and properties of BiVO{sub 3} (BVO) thin films, grown on (001) SrTiO{sub 3} and LaAlO{sub 3}, using the pulsed laser deposition technique. Bi and V are in 3+ oxidation states as measured by using x-ray photoelectrons spectroscopy. BVO exhibits a Curie-Weiss paramagnetic behaviour and about −26 K Weiss temperature. This demonstrates the presence of a strong correlation effect due to the spin fluctuation. Additionally, these films exhibit a semiconducting behaviour owing to the thermally activated conduction process. A plausible explanation of the observed properties is presented by comparing with the closely related LaVO{sub 3} and other orthovanadates.

  11. CAN WE CONFIDENTLY STUDY VO2 KINETICS IN YOUNG PEOPLE?

    Directory of Open Access Journals (Sweden)

    Samantha G. Fawkner

    2007-09-01

    Full Text Available The study of VO2 kinetics offers the potential to non-invasively examine the cardiorespiratory and metabolic response to dynamic exercise and limitations to every day physical activity. Its non-invasive nature makes it hugely attractive for use with young people, both healthy and those with disease, and yet the literature, whilst growing with respect to adults, remains confined to a cluster of studies with these special populations. It is most likely that this is partly due to the methodological difficulties involved in studying VO2 kinetics in young people which are not present, or present to a lesser degree, with adults. This article reviews these methodological issues, and explains the main procedures that might be used to overcome them

  12. Cambios en el porcentaje de sodio intercambiable (PSI y la relación de absorción de sodio (RAS de un suelo y su influencia en la actividad y biomasa microbiana

    Directory of Open Access Journals (Sweden)

    Torrente Trujillo Armando

    2011-03-01

    Full Text Available

    Con el objetivo de evaluar los cambios en el PSI, la RAS y su influencia en la actividad y  biomasa  microbiana  del suelo,  se aplicaron  diversas  concentraciones  de vinaza  como enmienda procedente de la industria de alcohol carburante, sobre un suelo afectado por sodicidad con severas limitaciones en las condiciones físicas, químicas y biológicas. Se aplicó un diseño en bloques completos al azar que incluye cuatro tratamientos y tres repeticiones, y muestreos de suelo al inicio y final del proceso a tres profundidades (0-20, 20-40 y 40-60 cm, cuyas variables de respuesta a medir fueron  la respiración, C- biomasa microbiana, MO%, pH, CIC, CE, RAS y PSI. La actividad biológica (CO2 y el C-biomasa microbiana mostraron

    incrementos significativos en el rango ideal para el establecimento del cultivo de caña.

  13. Cambios en el porcentaje de sodio intercambiable (PSI y la relación de absorción de sodio (RAS de un suelo y su influencia en la actividad y biomasa microbiana

    Directory of Open Access Journals (Sweden)

    Cesar A Gasca

    2011-01-01

    Full Text Available Con el objetivo de evaluar los cambios en el PSI, la RAS y su influencia en la actividad y biomasa microbiana del suelo, se aplicaron diversas concentraciones de vinaza como enmienda procedente de la industria de alcohol carburante, sobre un suelo afectado por sodicidad con severas limitaciones en las condiciones físicas, químicas y biológicas. Se aplicó un diseño en bloques completos al azar que incluye cuatro tratamientos y tres repeticiones, y muestreos de suelo al inicio y final del proceso a tres profundidades (0-20, 20-40 y 40-60 cm, cuyas variables de respuesta a medir fueron la respiración, C- biomasa microbiana, MO%, pH, CIC, CE, RAS y PSI. La actividad biológica (CO2 y el C-biomasa microbiana mostraron incrementos significativos en el rango ideal para el establecimento del cultivo de caña.

  14. Equation for estimating tree biomass in tropical forests of Costa Rica Ecuación para estimar la biomasa arbórea en los bosques tropicales de Costa Rica

    Directory of Open Access Journals (Sweden)

    Shu Wei-Chou

    2013-06-01

    methodological approach to estimate forest biomass, which is very useful to support decision-making on carbon storage in tropical forests. Biomass determination in the field in future plots is going to help the calibration of this approach to estimate biomass stored in tropical forests.Una de las medidas más relevantes para la mitigación del cambio climático es la conservación y regeneración del bosque en nuestros países.  La cantidad de carbono que se almacena en la biomasa arbórea pasa a ser una medida relevante para la política pública. El presente trabajo analiza la asociación que tienen algunas variables dasométricas, fácilmente medibles, asociadas a la biomasa, con el propósito de estimarla indirectamente, dado que la medición directa de la biomasa arbórea es un trabajo complejo y tiene un costo muy elevado.  El objetivo general del estudio fue hacer un análisis del comportamiento de las variables dasométricas fácilmente medibles para predecir biomasa arbórea con datos de dos bosques tropicales de Costa Rica, con el propósito de analizar su posible aplicación generalizada en los bosques tropicales de todo el país. Mediante una revisión bibliográfica, se determinaron cuatro posibles modelos que estiman biomasa en bosques tropicales. Se evaluaron 907 árboles con diámetro a la altura de pecho (dap mayor a 10 cm en dos bosques tropicales de Costa Rica (Parque Nacional Corcovado en el suroeste y Fila Carbón en el sureste, vertiente del Caribe, generando una estimación de biomasa lo más precisa posible. Se realizó un análisis de las variables de los árboles (densidad específica de la madera, altura total y dap y su biomasa, con el fin de desarrollar el modelo que facilitara la predicción de esta. El modelo final utiliza como variables independientes el dap y la densidad.  Con el dap se da el hecho de que existe una alta correlación con la altura total, la cual es muy difícil de obtener en el campo, de modo que se decidió no utilizarla. La

  15. SIP协议在VoIP中的应用

    Institute of Scientific and Technical Information of China (English)

    卢茵; 黄本雄

    2007-01-01

    SIP协议是NGN中的重要协议,越来越得到业界的重视。本文简单介绍了VoIP和SIP协议的含义,并从背景、功能、主要消息这几个方面对SIP协议的工作原理进行了介绍,分析了SIP呼叫建立的流程。

  16. Implementation of Cloud Computing into VoIP

    Directory of Open Access Journals (Sweden)

    Floriana GEREA

    2012-08-01

    Full Text Available This article defines Cloud Computing and highlights key concepts, the benefits of using virtualization, its weaknesses and ways of combining it with classical VoIP technologies applied to large scale businesses. The analysis takes into consideration management strategies and resources for better customer orientation and risk management all for sustaining the Service Level Agreement (SLA. An important issue in cloud computing can be security and for this reason there are several security solution presented.

  17. Extending Tactical Fleet Communications Through VoIP

    Science.gov (United States)

    2014-09-01

    Information Assurance Certification and Accreditation Process (DIACAP) Package and DIACAP Scorecard can help ensure a DOD organization’s VoIP system...standard used to compress the signal for transmission. As with any compression technology, codec standards must balance a tradeoff between payload...46]. EIA-530 is a Telecommunications Industry Association standard for balanced serial interfaces typically using a 25-pin, “D-type,” connector that

  18. VoIP系统中的回声分析

    Institute of Scientific and Technical Information of China (English)

    耿洁

    2008-01-01

    文章首先叙述了回声的产生过程以及影响声音质量的因素,然后分析了回声消除器和抑制器解决回声的原理.最后得出结论.利用VoIP性能管理的架构来解决回声问题是可行的.

  19. Vođena tkivna regeneracija u rekonstraktivnoj parodontnoj kirurgiji

    OpenAIRE

    Jorgić-Srdjak, Ksenija; Plančak, Darije; Potočki-Tukša, Karmen

    1996-01-01

    Glavni cilj parodontne terapije jest potpuna regeneracija izgubljenih potpornih tkiva zuba. Uobičajenom konzervativnom i kirurškom terapijom nastaje apikalna proliferacija i migracija epitela uzduž korijenske površine. Tako stvoren dugi spojni epitel isključuje regeneraciju ostalih tkiva potpornih parodontnih struktura, u prvome redu kosti i periodontnog ligamenta. Koncepcija vođene tkivne regeneracije (Guided Tissue Regeneration - GTR) podrazumijeva da se zaustavi ili spriječi apikalna p...

  20. In situ high-pressure synchrotron X-ray diffraction study of the structural stability in NdVO{sub 4} and LaVO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Física Aplicada-ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain); Popescu, C. [CELLS-ALBA Synchrotron Light Facility, Cerdanyola, 08290 Barcelona (Spain); Achary, S.N.; Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Bettinelli, M. [Luminiscent Materials Laboratory, DB and INSTM, Università di Verona, Strada Le Grazie 15, I-37134 Verona (Italy)

    2014-02-01

    Highlights: • NdVO{sub 4} and LaVO{sub 4} were studied under high pressure using synchrotron powder XRD. • Both compounds exhibit first-order phase transitions. • In NdVO{sub 4} the transition involves a symmetry breaking and in LaVO{sub 4} is isomorphic. • The crystal structures of the high-pressure phases are assigned. • Axial and bulk compressibilities are determined. - Abstract: Room-temperature angle-dispersive X-ray diffraction measurements on zircon-type NdVO{sub 4} and monazite-type LaVO{sub 4} were performed in a diamond-anvil cell up to 12 GPa. In NdVO{sub 4}, we found evidence for a non-reversible pressure-induced structural phase transition from zircon to a monazite-type structure at 6.5 GPa. Monazite-type LaVO{sub 4} also exhibits a phase transition but at 8.6 GPa. In this case the transition is reversible and isomorphic. In both compounds the pressure induced transitions involve a large volume collapse. Finally, the equations of state and axial compressibilities for the low-pressure phases are also determined.

  1. Crystal structure and electrical properties of K/sub 3/Bi/sub 2/(VO/sub 4/)/sub 3/, a new potassium bismuth vanadate

    Energy Technology Data Exchange (ETDEWEB)

    Debreuille-Gresse, M.F.; Abraham, F.

    1987-12-01

    K/sub 3/Bi/sub 2/(VO/sub 4/)/sub 3/ crystallizes in the space group C2/c, a = 13.957(4), b = 13.858(4), c = 7.095(2) A, ..beta.. = 112.80(3)/sup 0/, Z = 4. The crystal structure was determined from single-crystal intensity data obtained by means of an automated four-circle diffractometer and refined to the conventional values R = 0.050 and R/sub w/ = 0.059 for 1498 observed reflections. The structure is characterized by a three-dimensional network of Bi/sub 2/O/sub 10/ units and VO/sub 4/ tetrahedra. A Bi/sub 2/O/sub 10/ unit is formed by two BiO/sub 6/ octahedra sharing an edge. K/sup +/ ions occupy three different crystallographic sites. One of them has a high thermal vibration which could reflect ionic mobility. The ionic conductivity highly increases at 790 K. DSC measurements show a reversible transition at this temperature. One K atom, and only one, can be substituted by one Na atom to give NaK/sub 2/Bi/sub 2/(VO/sub 4/)/sub 3/; this substitution improves the conductivity.

  2. Synthesis and photocatalytic properties of InVO4 sol containing nanocrystals by mild hydrothermal processing

    Institute of Scientific and Technical Information of China (English)

    FANG Hai-bo; XU Ming-xia; GE Lei; HE Zhi-yuan

    2006-01-01

    The precursor precipitation of InVO4 was synthesized by co-precipitation using indium trichloride (InCl3),ammonium metavanadate (NH4VO3) and ammonia (NH3-H2O) as raw materials. The InVO4 sols with orthorhombic phase were obtained by hydrothermal treatment (the precursor precipitation solution at 423 K,for 4 h). The precursor and sol of InVO4 were characterized by X-ray diffraction (XRD),Fourier Transform Infra-red spectra (FT-IR),scanning electron microscopy (SEM) measurements. The XRD patterns indicate that the InVO4 precursor is amorphous phase,InVO4 sol contains orthorhombic InVO4 nanocrystals. The results also reveal that the pH value of the reaction mixture and reaction temperature play important roles to the target phase. InVO4-TiO2 thin films on glass slides were prepared by the dip-coating method from the composite sol. The photocatalytic properties of the InVO4-TiO2 thin films were investigated by the photocatalytic degradation of methyl orange solution. The results indicate that it has better photocatalytic activities than pure TiO2 thin films or pure InVO4 thin films with UV light.

  3. Effect of W addition on the electrical switching of VO2 thin films

    Science.gov (United States)

    Rajeswaran, Bharathi; Umarji, Arun M.

    2016-03-01

    Vanadium Oxide has been a frontrunner in the field of oxide electronics because of its metal-insulator transition (MIT). The interplay of different structures of VO2 has played a crucial role in deciding the magnitude of the first order MIT. Substitution doping has been found to introduce different polymorphs of VO2. Hence the role of substitution doping in stabilizing the competing phases of VO2 in the thin film form remains underexplored. Consequently there have been reports both discounting and approving such a stabilization of competing phases in VO2. It is reported in the literature that the bandwidth of the hysteresis and transition temperature of VO2 can be tuned by substitutional doping of VO2 with W. In this work, we have adopted a novel technique called, Ultrasonic Nebulized Spray Pyrolysis of Aqueous Combustion Mixture (UNSPACM) to deposit VO2 and W- doped VO2 as thin films. XRD and Raman spectroscopy were used to investigate the role of tungsten on the structure of VO2 thin films. Morphology of the thin films was found to be consisting of globular and porous nanoparticles of size ˜ 20nm. Transition temperature decreased with the addition of W. We found that for 2.0 at % W doping in VO2, the transition temperature has reduced from 68 o C to 25 o C. It is noted that W-doping in the process of reducing the transition temperature, alters the local structure and also increases room temperature carrier concentration.

  4. Oxidizing annealing effects on VO{sub 2} films with different microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Yan-Kun, E-mail: douyankun3@163.com; Li, Jing-Bo, E-mail: lijb@bit.edu.cn; Cao, Mao-Sheng, E-mail: caomaosheng@bit.edu.cn; Su, De-Zhi, E-mail: sudezhihefish@126.com; Rehman, Fida, E-mail: fida_ph@yahoo.com; Zhang, Jia-Song, E-mail: zhangjiasong@126.com; Jin, Hai-Bo, E-mail: hbjin@bit.edu.cn

    2015-08-01

    Vanadium dioxide (VO{sub 2}) films have been prepared by direct-current magnetron sputter deposition on m-, a-, and r-plane sapphire substrates. The obtained VO{sub 2} films display different microstructures depending on the orientation of sapphire substrates, i.e. mixed microstructure of striped grains and equiaxed grains on m-sapphire, big equiaxed grains on a-sapphire and fine-grained microstructure on r-sapphire. The VO{sub 2} films were treated by the processes of oxidation in air. The electric resistance and infrared transmittance of the oxidized films were characterized to examine performance characteristics of VO{sub 2} films with different microstructures in oxidation environment. The oxidized VO{sub 2} films on m-sapphire exhibit better electrical performance than the other two films. After air oxidization for 600 s at 450 °C, the VO{sub 2} films on m-sapphire show a resistance change of 4 orders of magnitude over the semiconductor-to-metal transition. The oxidized VO{sub 2} films on a-sapphire have the highest optical modulation efficiency in infrared region compared to other samples. The different performance characteristics of VO{sub 2} films are understood in terms of microstructures, i.e. grain size, grain shape, and oxygen vacancies. The findings reveal the correlation of microstructures and performances of VO{sub 2} films, and provide useful knowledge for the design of VO{sub 2} materials to different applications.

  5. Synthesis and modification of FeVO4 as novel anode for lithium-ion batteries

    Science.gov (United States)

    Liu, Xiaolin; Cao, Yuancheng; Zheng, Hao; Chen, Xiao; Feng, Chuanqi

    2017-02-01

    FeVO4 and FeVO4/graphene nanorods were synthesized successfully by combining a facile hydrothermal and heat treatment method. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and transmission electron microscopy (TEM) techniques. The content of graphene in FeVO4/graphene was determined by thermogravimetric analysis (TG). The electrochemical properties of the samples were also investigated by battery testing system. The results showed that the FeVO4 formed were taken on morphology of nanorods with the length between 0.5 and 1 μm and the diameter in range of 50 to 100 nm. Besides, the size of FeVO4/graphene was smaller than that of pure FeVO4. The content of graphene in composite was about 25.0% by weight. The reversible discharge capacities of FeVO4 and FeVO4/graphene were 405.2 mAh g-1 and 1046.5 mAh g-1 separately after 100 cycles at the current density of 100 mAh g-1 in the voltage range of 0.01-3 V. The reasons for the FeVO4/graphene composite to behave outstanding electrochemical properties were also discussed. The FeVO4/graphene composite can be a novel and promising anode material for lithium ion battery application.

  6. VO2@RER1.0: a novel submaximal cardiopulmonary exercise index.

    Science.gov (United States)

    Chin, Clifford; Kazmucha, Jeffrey; Kim, Nancy; Suryani, Reny; Olson, Inger

    2010-01-01

    Maximal oxygen consumption (VO2max) is the "gold standard" by which to assess functional capacity; however, it is effort dependent. VO2@RER1.0 is defined when VO2 = VCO2. Between December 22, 1997 and November 9, 2004, 305 pediatric subjects underwent cycle ergometer cardiopulmonary exercise testing, exercised to exhaustion, and reached a peak respiratory exchange ratio > or = 1.10. Group 1 subjects achieved a peak VO2 > or = 80% of predicted VO2max; group 2 subjects achieved a peak VO2 equation was created. VO2@RER1.0 data from groups 2 and 3 were plotted onto the normative graph. Contingency table and relative-risk analysis showed that an abnormal VO2@RER1.0 predicted an abnormal peak VO2(positive-predictive value 83%, negative-predictive value 85%, sensitivity 84%, and specificity 84%). VO2@RER1.0 is a highly sensitive, specific, and predictive submaximal index of functional capacity. This submaximal index is easy to identify without subjectivity. This index may aid in the evaluation of subjects who cannot exercise to maximal parameters.

  7. Efecto de fertilización nitrogenada en la producción de biomasa y calidad de aceite esencial en Lippia alba (Miller, Pronto alivio.

    Directory of Open Access Journals (Sweden)

    Sánchez O. M.

    2004-04-01

    Full Text Available En el Campo Experimental de la Universidad Nacional de Colombia sede Palmira (CEUNP se realizó un ensayo para evaluar el efecto de la fertilización nitrogenada, aplicando dos fuentes (gallinaza y urea en dos niveles (50 y 100 kg/ha de nitrógeno y dos frecuencias de corte (dos y cuatro meses. En el lote experimental se situaron 15 parcelas, en un diseño de bloques completos al azar, con cinco tratamientos y tres repeticiones. Para el análisis de la información se utilizó el programa estadístico SAS. El máximo rendimiento de biomasa y aceites esenciales se obtuvo con la aplicación de 100 kg/ha de nitrógeno en forma de urea y la frecuencia de corte cada dos meses. Los niveles de extracción de Lippia alba en nitrógeno variaron entre 79.7 y 128.5; fósforo entre 24.5 y 30.5; potasio entre 114.6 y 138.8 y calcio entre 100 y 150 kg/ha. El aceite esencial estuvo compuesto mayoritariamente por carvona y limoneno. Palabras claves: Fertilización nitrogenada, Lippia alba, Rendimientos biomasa, aceites esenciales, pronto alivio. ABSTRACT Nitrogenous fertilization effects in the Lippia alba production and quality. In the Experimental Center of the National University of Colombia-Palmira (CEUNP a experiment was realized to evaluate the effect of the nitrogenous fertilization, using two sources (gallinaza and urea at two levels (50 and 100 kg/ha of nitrogen and two cutting frequencies (each two and four months. In the experimental area 15 plots were planted, in a randomized Complete Blocks design random (RCBD with five treatments and three repetitions to measure the following variables: production of fresh matter, content of dry matter, nutrients extraction and content of essential oils. The analysis of variance used the statistical program SAS. The maximum yield of biomass and essential was obtained oils combining the fertilization with 100 kg/ha of nitrogen as urea and the cutting frequency every of two months. The levels of nutrients

  8. Experimental numerical study utilizing CFD in a stratified gasifier operating with biomass; Estudio numerico experimental de un gasificador estratificado que opera con biomasa, utilizando CFD

    Energy Technology Data Exchange (ETDEWEB)

    Rogel Ramirez, Alejandro

    2007-07-01

    The central idea behind this work is the developing of a numeric-experimental model, useful to optimize the biomass stratified gasifier design. Firstly, model validation will be carried up by comparison with reference experimental data available. This study describes a 1-D + 2-D numerical model used to simulate the gasification of pine wood pellets in a stratified downdraft gasifier whereby Eulerian conservation equations are solved for particle and gas phase components, velocities and specific enthalpies. The model takes into account the biomass particle process such as heating up, drying, primary pyrolysis of biomass, secondary pyrolysis of tar, homogeneous reactions and heterogeneous combustion/gasification reactions, and particle size change. This CFD model can be used to predict temperature profiles, gas composition, producer gas lower heating value, and carbon conversion efficiency, and the reactor performance when operating parameters and feed properties are changed. The standard {kappa}-{epsilon} and RNG {kappa}-{epsilon} models were used to simulate the turbulent flow conditions. [Spanish] La idea central del presente trabajo es el desarrollo de un modelo numerico- experimental, para optimizar el diseno de gasificadores estratificados de biomasa. Primeramente, el modelo sera validado utilizando datos experimentales disponibles en la literatura. Este estudio describe un modelo numerico 1-D+2-D, utilizado para simular la gasificacion de 'pelets' de madera de pino en un gasificador estratificado de flujos paralelos, en el que se resuelven ecuaciones de conservacion Eulerianas para los componentes de la fase gaseosa, la fase solida, velocidades y entalpias especificas. El modelo considera procesos como: calentamiento, secado de la biomasa, pirolisis primaria de la madera, pirolisis secundaria de los alquitranes, reacciones homogeneas, reacciones heterogeneas de combustion/gasificacion y cambio en el tamano de la particula. Este modelo CFD puede ser

  9. WO3/W:BiVO4/BiVO4 graded photoabsorber electrode for enhanced photoelectrocatalytic solar light driven water oxidation.

    Science.gov (United States)

    Choi, Junghyun; Sudhagar, Pitchaimuthu; Kim, Joo Hyun; Kwon, Jiseok; Kim, Jeonghyun; Terashima, Chiaki; Fujishima, Akira; Song, Taeseup; Paik, Ungyu

    2017-02-08

    We demonstrate the dual advantages of graded photoabsorbers in mesoporous metal oxide-based hetero interfacial photoanodes in improving photogenerated charge carrier (e(-)/h(+)) separation for the solar light-driven water-oxidation process. The pre-deposition of sol-gel-derived, tungsten-doped bismuth vanadate (W:BiVO4) onto a primary BiVO4 water oxidation layer forms graded interfaces, which facilitate charge transfer from the primary photoabsorber to the charge transport layer, thereby superseding the thickness-controlled charge recombination at the BiVO4 water oxidation catalyst. As a result, the WO3/BiVO4 hetero photoanode containing the photoactive W:BiVO4 interfacial layer showed 130% higher photocurrent than that of the interfacial layer-free hetero photoelectrode owing to the enhanced charge separation led water oxidation process.

  10. VoIP体系在移动设备上的Java实现%Realization of VoIP System on Mobile Devices at the Java

    Institute of Scientific and Technical Information of China (English)

    宋敦波; 卢如海

    2009-01-01

    VoIP是通过分组交换网来执行语音数据传输的一种技术.会议初始协议(SIP)是一种基于应用层的信令控制协议,由于具有简单、灵活和良好扩展的体系结构,将其融入数字语音通信技术中,建立基于SIP的VoIP网络,将会成为下一代VoIP技术的发展趋势之一.为此,在基于SIP协议的VoIP网络实现模型基础上,文章阐述了SIP在VoIP网络中的实现原理,以及SIP对整个对话的控制过程.

  11. 中兴:企业VoIP解决方案%ZTE: the Enterprise VoIP Solution

    Institute of Scientific and Technical Information of China (English)

    罗和谭

    2005-01-01

    VoIP其全称为:Voice Over Internet Protocol,又称IP电话或者网络电话。IP电话是目前Internet应用领域的一个热门话题,IP电话利用因特网实时传送数字话音信号,实现长途或市内通话的一种先进的通信方式。

  12. Synthesis, surface and optical properties of Ag{sub 2}Cu(VO{sub 3}){sub 4} and Cu(VO{sub 3}){sub 2} vanadates

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Xuebin [Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116 (China); Wan, Yingpeng; Li, Yuze [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Lin [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2016-04-15

    Graphical abstract: - Highlights: • The well-developed Ag{sub 2}Cu(VO{sub 3}){sub 4} and Cu(VO{sub 3}){sub 2} were developed. • The vanadates show typical indirect allowed transitions narrow band energy. • Ag{sub 2}Cu(VO{sub 3}){sub 4} and Cu(VO{sub 3}){sub 2} present photocatalytic activity driven by visible-light. • Photocatalysis was discussed on the band energy and positions. - Abstract: Ag{sub 2}Cu(VO{sub 3}){sub 4} and Cu(VO{sub 3}){sub 2} were prepared via the sol–gel chemical synthesis. The phase formation was confirmed by X-ray powder polycrystalline diffraction (XRD) measurements. The surface properties were measured with the scanning electron microscope (SEM), energy dispersive spectra (EDS), transmission electron microscopy (TEM), and nitrogen adsorption–desorption isotherms. The optical properties and the band-gap structures were investigated. The vanadates have efficient optical absorption in the UV to visible wavelength region with an indirect allowed transition. Ag{sub 2}Cu(VO{sub 3}){sub 4} has smaller band gap (1.85 eV) than that of Cu(VO{sub 3}){sub 2} (2.03 eV). The narrowed band gap is due to the hybridization between the Ag-4d and O-2p in the valence band. The photocatalysis was investigated by photodegradation of methylene blue (MB) solutions excited by the light with wavelength longer than 420 nm. Correspondingly Ag{sub 2}Cu(VO{sub 3}){sub 4} has more efficient photocatalytic activity on MB photodegradation than that of Cu(VO{sub 3}){sub 2}. The photocatalytic mechanisms were suggested according to the band positions and the trapping experiments.

  13. Novel cathode materials LixNa2-xV2O6 (x = 2, 1.4, 1, 0) for high-performance lithium-ion batteries

    Science.gov (United States)

    Li, Kaiqi; Cao, Liufei; Huang, Zheng; Chen, Liang; Chen, Zhongxue; Fu, Chaopeng

    2017-03-01

    In this work, sodium doped LiVO3 cathode is proposed to achieve enhanced cycling performance for lithium ion battery (LIB) application. LixNa2-xV2O6 (x = 2, 1.4, 1, 0) compounds have been prepared and characterized, and X-ray diffraction patterns confirmed the successful Na doping with various amounts in the LiVO3. The electrochemical performances of the various Na doped compounds LiVO3, Li1.4Na0.6V2O6, LiNaV2O6, and NaVO3 are evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results reveal that Na-doping amount strongly affects the electrochemical performance, and LiNaV2O6 (x = 1) is considered as the optimized Na doped compound for LIB cathodes. The LiNaV2O6 cathode displays enhanced cycling and rate performances as a specific capacity of 193 mAh g-1 at 0.5 C after 100 cycles is delivered. The enhanced performance is explained that the doping of Na can provide good channels and increase Li+ diffusion coefficient for lithium ion intercalation/deintercalation.

  14. Carbon quantum dots coated BiVO{sub 4} inverse opals for enhanced photoelectrochemical hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Feng; Shen, Mingrong; Fang, Liang, E-mail: zhkang@suda.edu.cn, E-mail: lfang@suda.edu.cn [College of Physics, Optoelectronics and Energy and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn, E-mail: lfang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Wang, Junling [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-04-13

    Carbon quantum dots (CQDs) coated BiVO{sub 4} inverse opal (io-BiVO{sub 4}) structure that shows dramatic improvement of photoelectrochemical hydrogen generation has been fabricated using electrodeposition with a template. The io-BiVO{sub 4} maximizes photon trapping through slow light effect, while maintaining adequate surface area for effective redox reactions. CQDs are then incorporated to the io-BiVO{sub 4} to further improve the photoconversion efficiency. Due to the strong visible light absorption property of CQDs and enhanced separation of the photoexcited electrons, the CQDs coated io-BiVO{sub 4} exhibit a maximum photo-to-hydrogen conversion efficiency of 0.35%, which is 6 times higher than that of the pure BiVO{sub 4} thin films. This work is a good example of designing composite photoelectrode by combining quantum dots and photonic crystal.

  15. In situ Raman spectroscopy study of metal-enhanced hydrogenation and dehydrogenation of VO2

    Science.gov (United States)

    Wu, Hao; Fu, Qiang; Bao, Xinhe

    2016-11-01

    Vanadium dioxide (VO2) has a phase transition from insulator to metal at 340 K, and this transition can be strongly modified by hydrogenation. In this work, two dimensional (2D) VO2 sheets have been grown on Si(1 1 1) surfaces through chemical vapor deposition, and metal (Au, Pt) thin films were deposited on VO2 surfaces by sputtering. The hydrogenation and dehydrogenation of VO2 and metal-decorated VO2 structures in H2 and in air were in situ studied by Raman. We found that hydrogenation and dehydrogenation temperatures have been significantly decreased with the VO2 surface decorated by Au and Pt. The enhanced hydrogenation and dehydrogenation reactions can be attributed to catalytic dissociation of H2 and O2 molecules on metal surfaces and subsequent spillover of dissociated H and O atoms to the oxide surfaces.

  16. Insights into Stabilization of the 99TcVO Core for Synthesis of 99TcVO Compounds

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Donna; Burton-Pye, Benjamin P.; Lukens, Wayne W.; Howell, Robertha C.; Francesconi, Lynn C.

    2014-01-01

    Synthesis of technetium-99 (99Tc; t1/2: 2.1 105 years, max: 253 keV) materials is of importance in studies of the nuclear fuel cycle where Tc is a major fission product (6percent thermal yield from 235U and 239Pu), in understanding radioactive tank waste composition, and in identifying 99mTc compounds for nuclear medicine imaging. One of the most useful synthetic starting materials, (NBu4)TcOCl4, is susceptible to disproportionation in water to form TcO4 and TcIV species, especially TcO2 2H2O. This unwanted reaction is especially problematic when working with ligands bearing hard donor atoms, such as oxygen, where the stability with the soft TcV=O3+ core may be low. Polyoxometalates (POMs) are such ligands. They possess defect sites with four hard oxygen atoms and show low (ca. 108) stability constants with transition metals. Tc complexes of POMs are molecular-level models for Tc metal oxide solid-state materials and can provide information on coordination and redox environments of metal oxides that stabilize low-valent Tc. In order to synthesize pure Tc POM complexes [TcVO(1-P2W17O61)]7 (TcVO-1) and [TcVO(2-P2W17O61)]7 (TcVO-2) from (NBu4)TcOCl4, we have identified strategies that minimize formation of TcIV species and optimize the formation of pure TcV species. The parameters that we consider are the amount of ethylene glycol, which is employed as a transfer ligand to prevent hydrolysis of (NBu4)TcOCl4, and the precipitating agent. The TcIV species that contaminates the non-optimized syntheses is likely a TcIV -oxido-bridged dimer [TcIV-(-O)2-TcIV]. We also employ a novel procedure where the 2 ligand is photoactivated and reduced (in the presence of a sacrificial electron donor) to subsequently reduce TcVIIO4 to an isolatable TcVO-2 product that is remarkably free of TcIV.

  17. Secuestro de carbono en la biomasa aérea de un sistema agrosilvopastoril de Cocos nucifera, Leucaena leucocephala Var. Cunningham y Pennisetum purpureum Cuba CT-115

    Directory of Open Access Journals (Sweden)

    J. M. Anguiano

    2013-01-01

    Full Text Available Con el objetivo de estimar el secuestro de carbono en la biomasa aérea de un sistema agrosilvopastoril (sasp compuesto por cocotero (Cocos nucifera, Leucaena leucocephala Var. Cunningham sembrada en alta densidad y Pennisetum purpureum Cuba CT-115, se llevó a cabo un estudio en un suelo con textura franco arcillo- arenosa. Se utilizó un diseño en bloques al azar con arreglo en parcelas divididas con cuatro tratamientos 0, 40, 60 y 80 mil árboles de leucaena ha-1 y tres repeticiones; la evaluación duró desde su establecimiento hasta 340 días de edad. Los resultados muestran diferencia estadística (P<0.001 en el secuestro de carbono con 101.19d, 109.73c, 122.00b y 128.62a t C+ha-1año-1 para los sasp de 0, 40, 60 y 80 mil plantas de leucaena ha-1, respectivamente. El mayor aporte de secuestro de carbono lo realizó el cocotero que aportó del 60 al 80% del total del sasp y existió una relación inversa de secuestro de carbono de la gramínea al incrementar la densidad de la leguminosa. El tratamiento que incorpora la siembra en alta densidad de la leguminosa arbórea logró un mayor secuestro de carbono.

  18. LA BIOMASA COMO ALTERNATIVA AL PETRÓLEO PARA LA OBTENCIÓN DE PRODUCTOS QUÍMICOS: ACETONA Y ETANOL COMO MOLÉCULAS PLATAFORMA

    Directory of Open Access Journals (Sweden)

    Jorge Quesada

    2014-01-01

    Full Text Available En este trabajo se pretende reflejar el potencial de la biomasa como materia prima para la obtención de productos químicos de elevado valor añadido, integrando su viabilidad económica y técnica dentro del concepto de biorefinería. Considerando el gran número de trabajos existentes acerca de la obtención de biocombustibles, se hace hincapié en el aprovechamiento de los subproductos de estos procesos, abordando la transformación de dos de las moléculas plataforma de mayor proyección: el etanol y la acetona. Si bien gran parte de los procesos químicos que se exponen no son novedosos, la necesidad de sustituir el petróleo por una materia prima renovable ha impulsado de nuevo su estudio y la optimización de los parámetros que actualmente limitan su implantación en la industria, desarrollando nuevos catalizadores y estudiando la influencia de diferentes condiciones de reacción.

  19. Abundancia y biomasa de macroinvertebrados edáficos en la temporada lluviosa, en tres usos de la tierra, en los Andes colombianos

    Directory of Open Access Journals (Sweden)

    Pardo Luis C

    2006-03-01

    Full Text Available COMPENDIO los usos evaluados fueron pastizal, cafetal y bosque secundario (Vereda Villa del Rosario, Aprox. 3º 33' 16â€? Latitud Norte y 76º 36' 01â€? Longitud Oeste, altitud 1.500 a 1.820m., precipitación 960 a 1.050 mm/año, 19.8 a 21.2º C con la metodología TSBF. Se implementaron tres monolitos por uso y cada uno se subdividió en cuatro estratos (hojarasca, 0-10 cm, 10-20 cm, y 20-30 cm, las variables densidad y biomasa por parcela y estrato se examinaron a través de ANOVAS y Post-Anovas. En abundancia la supremacía fue de hormigas (25584 ejemplares, miriápodos (4808 ejemplares y lombrices (1984 ejemplares, la diferencia significativa la marcaron los miriápodos (F=4.84, P=0.014 asociados con bosque y cafetal con sombrío. En biomasa los grupos más importantes fueron miriápodos (701.05 g m-2, 58.71%, lombrices (90.64 g m-2; 7.59%, chisas (27.07 g m-2; 2.26% hor­migas (20.90 g m-2; 1.75% y arañas (15.71 g m-2 ; 1.31%, con diferencias significativas en hormigas (F=4.17, P=0.024 y arañas (F=3.43, P=0.4024; También hubo diferencias estadísticas significativas en la densidad y biomasa de macroinvertebrados y los estratos de los monolitos, los resultados indican que estos organismos expresan en su población y biomasa respuestas ambientales asociadas más con la estructura del agroecosistema que con la variación química, física o microbiológica del hábitat; se recomienda discriminar taxonómicamente los grupos funcionales y ampliar los muestreos a la temporada seca. Palabras clave: uso del suelo, macroinvertebrados edáficos, densidad, abundancia, agroecosistemas, Andes colombianos. ABSTRACT Abundance and biomass of soil macroinvertabrates during the rainy season in three land use systems in the Colombian Andes. Using the TSBF methodology, three land use systems—pastures, coffee plantation, and secondary forest— were evaluated in the rural community of Villa del Rosario, located in the

  20. EFECTO DEL ÁCIDO SALICÍLICO EN EL CRECIMIENTO DE LA RAÍZ Y BIOMASA TOTAL DE PLÁNTULAS DE TRIGO

    Directory of Open Access Journals (Sweden)

    Cesar J. Tucuch Haas

    2015-03-01

    Full Text Available Se reportan los resultados de dos experimentos independientes para evaluar el efecto del ácido salicílico (AS en plántulas de trigo (Triticum aestivum L.. Las plántulas de ambos experimentos se germinaron y crecieron en agrolita contenida en tubos de PVC y en condiciones de cielo abierto bajo un diseño experimental completamente al azar con 8 repeticiones por tratamiento, las plántulas se asperjaron durante 5 días con 1 y 0.1 µM de AS o agua como control. Diez días después fueron cosechadas y realizadas las mediciones. Los resultados señalan que el AS favoreció significativamente el peso fresco de la raíz, así como la altura y el peso fresco de la biomasa total, en comparación con el control. El mejor tratamiento para estimular el crecimiento de plántulas de trigo fue el de 1µM de AS.

  1. The metropolitan VoD system based on ethernet/SCM PON

    Science.gov (United States)

    Ji, Wei; Yang, Hongliang; Feng, Dejun; Liu, Yang; Sun, Jande

    2008-11-01

    VoD is a very attractive service which used for entertainment, education and other purposes. In this paper, we present an evolution method that integrates the EPON and SCM-PON by WDM technology to provide high dedicated bandwidth for the metropolitan VoD services. Using DVB, IPTV protocol, unicasting and broadcasting method to maximize the system throughput and by numerical analysis, the hybrid PON system can implement the metropolitan VoD services.

  2. Enhancement in Photoelectrochemical Efficiency by Fabrication of BiVO4@MWCNT Nanocomposites

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2011-01-01

    Full Text Available An enormous enhancement in the photo-to-current conversion efficiency over the nanocomposite material composed by BiVO4 on the surface of MWCNTs, with respect to electrode of pure BiVO4, was observed. The heterojunction formed between MWCNTs and nano-BiVO4 is beneficial for the separation of photogenerated electrons and holes, resulting in more electrons that are able to transport efficiently to the surface and therefore enhance the photoefficiency.

  3. Monitoring changes in VO2max via the Polar FT40 in female collegiate soccer players.

    Science.gov (United States)

    Esco, Michael R; Snarr, Ronald L; Williford, Hank N

    2014-01-01

    This study was conducted to determine if the Polar FT40 could accurately track changes in maximal oxygen consumption (VO2max) in a group of female soccer players. Predicted VO2max (pVO2max) via the Polar FT40 and observed VO2max (aVO2max) from a maximal exercise test on a treadmill were determined for members of a collegiate soccer team (n = 20) before and following an 8-week endurance training protocol. Predicted (VO2max and aVO2max measures were compared at baseline and within 1 week post-training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference in aVO2max (pre = 43.6 ± 2.4 ml · kg · min(-1), post = 46.2 ± 2.4 ml · kg · min(-1), P < 0.001) and pVO2max (pre = 47.3 ± 5.3 ml · kg · min(-1), post = 49.7 ± 6.2 ml · kg · min(-1), P = 0.009) following training. However, predicted values were significantly greater at each time point compared to observed values (P < 0.001 at pre and P = 0.008 at post). Furthermore, there was a weak correlation between the change in aVO2max and the change in pVO2max (r = 0.18, P = 0.45). The Polar FT40 does not appear to be a valid method for predicting changes in individual VO2max following 8 weeks of endurance training in female collegiate soccer players.

  4. Solvothermal synthesis of Bi2O3/BiVO4 heterojunction with enhanced visible-light photocatalytic performances

    Science.gov (United States)

    Ying, Wu; Jing, Wang; Yunfang, Huang; Yuelin, Wei; Zhixian, Sun; Xuanqing, Zheng; Chengkun, Zhang; Ningling, Zhou; Leqing, Fan; Jihuai, Wu

    2016-08-01

    Novel, three-dimensional, flower-like Bi2O3/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solution of NaOH etching process. The as-obtained samples were fully characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Brunauer-Emmett-Teller surface area, and UV—vis diffuse-reflectance spectroscopy in detail. The crystallinity, microstructure, specific surface area, optical property and photocatalytic activity of samples greatly changed depending on solvothermal reaction time. The photocatalytic activities of samples were evaluated on the degradation of methyl orange (MO) under visible-light irradiation. The Bi2O3/BiVO4 exhibited much higher photocatalytic activities than pure BiVO4 and conventional TiO2 (P25). The result revealed that the three-dimensional heterojunction played a critical role in the separation of the electron and hole pairs and enhancement of the interfacial charge transfer efficiency, which was responsible for the enhanced photocatalytic activity. Project supported by the National Natural Science Foundation of China (Nos. 61306077, 21301060), the Fundamental Research Funds for the Central Universities (Nos. JB-ZR1109, JB-ZR1212), the National Science Foundation of Quanzhou City (No. 2014Z108), the Promotion Program for Young and Middle-aged Teachers in Science and Technology Research of Huaqiao University (No. ZQN-PY207), Discipline Innovation Team Project of Huaqiao University (No. 201320), and the Instrumental Analysis Center Huaqiao University.

  5. Selective synthesis and growth mechanism of CeVO4 nanoparticals via hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    LIU Fengzhen; SHAO Xin; YIN Yibin; ZHAO Limin; SUN Qiaozhen; SHAO Zhuwei; LIU Xuehua; MENG Xianhua

    2011-01-01

    Selective-controlled structure and shape of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). The influence of hydrothermal temperature, precursor solution concentration on the crystal and morphology of products were further studied. The results showed that the as-synthesized products exhibited pure single-crystal CeVO4 nanoparticles with tetragonal structure. The hydrothermal temperature and precursor solution concentration had important effects on the formation of CeVO4 nanoparticles. Furthermore, the growth mechanism of CeVO4 nanoparticles was explained with Ostwald ripening mechanism.

  6. QoS-guaranteed burst transmission for VoIP service over optical burst switching networks

    Science.gov (United States)

    Tachibana, Takuji; Kasahara, Shoji

    2007-08-01

    We propose a burst transmission method that guarantees the voice over Internet protocol (VoIP) service. The proposed method consists of three techniques: round-robin burst assembly with slotted scheduling, priority control with void filling, and hop-based preemption. Each technique is utilized so that the burst loss probability and the burst transmission delay satisfy VoIP quality of service (QoS). We evaluate by simulation the performance of the proposed method in NSFNET with 14 nodes. Numerical examples show that our proposed method is effective for guaranteeing the VoIP QoS while accommodating a large number of VoIP users.

  7. 基于EV-DO的VoIP QoS研究

    Institute of Scientific and Technical Information of China (English)

    肖清华; 李静

    2009-01-01

    为了对基于EV-DO的VoIP QoS有一个定性的了解,文章首先给出了基于EV-DO的QoS架构,提供了EV-DO为VoIP定制的QoS参数,而后在此基础上阐述了在EV-DO网络中实现VoIP端到端的QoS保证的技术方式,对今后顺利实现VoIP应用有着很好的指导意义.

  8. Fe2O3-Modified Porous BiVO4 Nanoplates with Enhanced Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    Ping Cai; Shu-Mei Zhou; De-Kun Ma; Shen-Nan Liu; Wei Chen; Shao-Ming Huang

    2015-01-01

    As BiVO4 is one of the most popular visible-light-responding photocatalysts, it has been widely used for visible-light-driven water splitting and environmental purification. However, the typical photocatalytic activity of unmodified BiVO4 for the degradation of organic pollutants is still not impressive. To address this limitation, we studied Fe2O3-modified porous BiVO4 nanoplates. Compared with unmodified BiVO4, the Fe2O3-modified porous BiVO4 nanoplates showed significantly enhanced photocatalytic activities in decomposing both dye and colorless pollutant models, such as rhodamine B (RhB) and phenol, respectively. The pseudo-first-order reaction rate constants for the degradation of RhB and phenol on Fe2O3-modified BiVO4 porous nanoplates are 27 and 31 times larger than that of pristine BiVO4, respectively. We also found that the Fe2O3 may act as an efficient non-precious metal co-catalyst, which is responsible for the excellent photocatalytic activity of Fe2O3/BiVO4. Graphical Abstract Fe2O3, as a cheap and efficient co-catalyst, could greatly enhance the photocatalytic activity of BiVO4 porous nanoplates in decomposing organic pollutants.

  9. VV and VO2 defects in silicon studied with hybrid density functional theory

    KAUST Repository

    Christopoulos, Stavros Richard G

    2014-12-07

    The formation of VO (A-center), VV and VO2 defects in irradiated Czochralski-grown silicon (Si) is of technological importance. Recent theoretical studies have examined the formation and charge states of the A-center in detail. Here we use density functional theory employing hybrid functionals to analyze the formation of VV and VO2 defects. The formation energy as a function of the Fermi energy is calculated for all possible charge states. For the VV and VO2 defects double negatively charged and neutral states dominate, respectively.

  10. Effects of body mass on exercise efficiency and VO2 during steady-state cycling.

    Science.gov (United States)

    Berry, M J; Storsteen, J A; Woodard, C M

    1993-09-01

    Oxygen uptake (VO2) and exercise efficiency during cycle ergometer exercise are considered to be independent of body mass. To determine the validity of this assumption, 50 females ranging in body mass from 41.5-98.9 kg exercised on a cycle ergometer with no load at 60 rpm and at 25, 50, 75, and 100 W at 60 and 90 rpm. Gross VO2 and efficiency, net VO2 and efficiency, work VO2 and efficiency, and delta efficiency were computed. Gross and net VO2 were significantly and positively correlated with body mass at all work rates and pedal frequencies. Gross efficiency was significantly and negatively correlated with body mass at all work rates and pedal frequencies. Work VO2 and body mass were not significantly correlated. The correlations between work and delta efficiency and body mass were not significant. Since body mass was found to be significantly correlated with gross VO2, the following equation was developed using stepwise multiple regression to predict gross VO2: VO2 (ml.min-1) = 10.9 (work rate, W) + 8.2 (pedal rate, rpm) + 8.3 (body mass, kg) - 559.6. These data suggest that body mass should be considered when estimating the oxygen uptake during cycle ergometer exercise.

  11. n-VO2/p-GaN based nitride-oxide heterostructure with various thickness of VO2 layer grown by MBE

    Science.gov (United States)

    Wang, Minhuan; Bian, Jiming; Sun, Hongjun; Liu, Weifeng; Zhang, Yuzhi; Luo, Yingmin

    2016-12-01

    High quality VO2 films with precisely controlled thickness were grown on p-GaN/sapphire substrates by oxide molecular beam epitaxy (O-MBE). Results indicated that a distinct reversible semiconductor-to-metal (SMT) phase transition was observed for all the samples in the temperature dependent electrical resistance measurement, and the influence of VO2 layer thickness on the SMT properties of the as-grown n-VO2/p-GaN based nitride-oxide heterostructure was investigated. Meanwhile, the clear rectifying transport characteristics originated from the n-VO2/p-GaN interface were demonstrated before and after SMT of the VO2 over layer, which were attributed to the p-n junction behavior and Schottky contact character, respectively. Moreover, the X-ray photoelectron spectroscopy (XPS) analyses confirmed the valence state of vanadium (V) in VO2 films was principally composed of V4+ with trace amount of V5+. The design and modulation of the n-VO2/p-GaN based heterostructure devices will benefit significantly from these achievements.

  12. 终端VoLTE与RCS融合方案研究%Research on Integration Scheme of VoLTE and RCS on Terminals

    Institute of Scientific and Technical Information of China (English)

    张达; 张婷; 戴国华

    2014-01-01

    介绍了VoLTE和RCS的发展历程,VoLTE与RCS融合是必然趋势,但在此过程中一些关键问题仍未达成一致,不同终端厂家在APN配置、协议栈架构、业务融合等方面实现迥异。通过对VoLTE与RCS融合关键问题进行详细分析,提出了终端VoLTE与RCS融合解决方案的建议。%The development history of VoLTE and RCS is introduced and the integration of them is the inevitable trend. Some critical problems still exist during the integration. Manufacturers behave differently in APN configuration, protocol stack architecture and business integration. By analyzing the key problems for the integration of VoLTE and RCS in detail, the integration solution of VoLTE and RCS on terminals is put forward.

  13. Octasic采用专有技术提供VoP整体解决方案%Octasic supplies VoP solution with specific technology

    Institute of Scientific and Technical Information of China (English)

    穆强

    2003-01-01

    @@ "VoP市场正在面临着这样一个事实--Cisco最近宣布它所销售的IP电话已经超过了100万部;所有主要的PBX供应商都在主推IP PBX产品;美国主要的基于语音服务的电信运营商,如MCI和Sprint最近也宣布了将其网络架构向VoP转型的庞大计划;同时基于VoP技术的3G网络也正在建设之中.而在亚洲和中国,通信设备制造商在发展VoP产品方面看上去比其他地区的同业者走得更快."加拿大Octasic公司CEO Michel Laurence对VoP市场的前景表现出十分乐观的态度.作为一家专业的VoP硅解决方案及技术服务提供商,Octasic也正在致力于对VoP市场的深入开发与有效覆盖.

  14. VoSeq: a voucher and DNA sequence web application.

    Directory of Open Access Journals (Sweden)

    Carlos Peña

    Full Text Available There is an ever growing number of molecular phylogenetic studies published, due to, in part, the advent of new techniques that allow cheap and quick DNA sequencing. Hence, the demand for relational databases with which to manage and annotate the amassing DNA sequences, genes, voucher specimens and associated biological data is increasing. In addition, a user-friendly interface is necessary for easy integration and management of the data stored in the database back-end. Available databases allow management of a wide variety of biological data. However, most database systems are not specifically constructed with the aim of being an organizational tool for researchers working in phylogenetic inference. We here report a new software facilitating easy management of voucher and sequence data, consisting of a relational database as back-end for a graphic user interface accessed via a web browser. The application, VoSeq, includes tools for creating molecular datasets of DNA or amino acid sequences ready to be used in commonly used phylogenetic software such as RAxML, TNT, MrBayes and PAUP, as well as for creating tables ready for publishing. It also has inbuilt BLAST capabilities against all DNA sequences stored in VoSeq as well as sequences in NCBI GenBank. By using mash-ups and calls to web services, VoSeq allows easy integration with public services such as Yahoo! Maps, Flickr, Encyclopedia of Life (EOL and GBIF (by generating data-dumps that can be processed with GBIF's Integrated Publishing Toolkit.

  15. Application technology of VoIP on 3G mobile network%VoIP在第三代移动网络中的应用技术

    Institute of Scientific and Technical Information of China (English)

    苏苇; 毛红艳

    2007-01-01

    发展移动网络中信5P23 VoIP技术的主要目的,一是为了节省带宽,提高频谱利用率;二是为了提供话音和数据统一的接口和平台.VoIP在有着广阔发展前景的同时,也面临着一些挑战,首先介绍了VoIP在GPRS、UMTS中的应用框架和关键技术,其次讨论了它的QoS问题.

  16. Bulk and electrochemical properties of BiVO4

    OpenAIRE

    Vinke, I.C.; Diepgrond, J. (Jan); Boukamp, B.A.; De, Vries, J.A.; Burggraaf, A.J.

    1992-01-01

    The mixed (oxygen ionic-electronic) conductor bismuth vanadate (BiVO4) was studied with respect to its electrochemical properties. The ionic transference numbers, measured by the concentration cell method in the temperature range of 800 to 1000 K, vary from 0.7 to 0.3. The total conductivity of this ceramic material isone order of magnitude lower than found for cubic yttria-stabilized zirconia (YSZ). The activation enthalpy for the electronic conductivity is high (193 kJ/mol) compared to the ...

  17. Creative MuVo2 FM 5GB

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    可存储多达2500首歌曲Creative MuVo2 FM 5GB设计轻巧简洁;尺寸只有67×665×20mm.内置了完备的FM收音/录音和语音录音功能.并设计了全新的摇杆按键,也是即插即用的大容量U盘,更具有高达98dB的信噪比,可更换式充电锂电池,

  18. VoCS : Sistema de almacenamiento voluntario en la nube

    OpenAIRE

    Schiavón Raineri, Ignacio Nicolás

    2012-01-01

    La computación en la nube responde a las necesidades del aumento de dispositivos conectados a Internet y el creciente volumen de datos manejados, ofreciendo acceso ubicuo y transparente a la información de forma segura. Esto ha tenido como consecuencia la apertura del mercado, ofreciendo muchas aplicaciones basadas en la nube como SkyDrive, Google Drive o Dropbox. VoCS (Volunteer Cloud Storage) es un sistema de almacenamiento voluntario en la nube de código abierto y seguro, que pretende ofre...

  19. VoIP Steganography and Its Detection - A Survey

    CERN Document Server

    Mazurczyk, Wojciech

    2012-01-01

    Steganography is an ancient art that encompasses various techniques of information hiding, the aim of which is to secret information into a carrier message. Steganographic methods are usually aimed at hiding the very existence of the communication. Due to the rise in popularity of IP telephony, together with the large volume of data and variety of protocols involved, it is currently attracting the attention of the research community as a perfect carrier for steganographic purposes. This paper is a survey of the existing VoIP steganography (steganophony) methods and their countermeasures.

  20. A distributed infrastructure for publishing VO services: an implementation

    Science.gov (United States)

    Cepparo, Francesco; Scagnetto, Ivan; Molinaro, Marco; Smareglia, Riccardo

    2016-07-01

    This contribution describes both the design and the implementation details of a new solution for publishing VO services, enlightening its maintainable, distributed, modular and scalable architecture. Indeed, the new publisher is multithreaded and multiprocess. Multiple instances of the modules can run on different machines to ensure high performance and high availability, and this will be true both for the interface modules of the services and the back end data access ones. The system uses message passing to let its components communicate through an AMQP message broker that can itself be distributed to provide better scalability and availability.

  1. Comprehensive picture of VO2 from band theory

    KAUST Repository

    Zhu, Zhiyong

    2012-08-28

    The structural, electronic, and magnetic features of the metal-insulator transition from the tetragonal rutile (R) to the monoclinic (M1) phase of VO2 are well reproduced by band theory using the modified Becke-Johnson exchange potential. Based on this description, we identify a tendency for monoclinic charge ordering in the R phase due to electronic correlations as the origin of the phase transition. Whereas, the structural changes are crucial for the gap opening in the M1 phase, spin degeneracy in both phases is stabilized by correlation-induced delocalization of the V3d electrons.

  2. Extraction Of Electronic Evidence From VoIP: Identification & Analysis Of Digital Speech

    Directory of Open Access Journals (Sweden)

    David Irwin

    2012-09-01

    Full Text Available The Voice over Internet Protocol (VoIP is increasing in popularity as a cost effective and efficient means of making telephone calls via the Internet. However, VoIP may also be an attractive method of communication to criminals as their true identity may be hidden and voice and video communications are encrypted as they are deployed across the Internet. This produces in a new set of challenges for forensic analysts compared with traditional wire-tapping of the Public Switched Telephone Network (PSTN infrastructure, which is not applicable to VoIP. Therefore, other methods of recovering electronic evidence from VoIP are required.  This research investigates the analysis and recovery of digitised human, which persists in computer memory after a VoIP call.This paper proposes a proof of concept how remnants of digitised human speech from a VoIP call may be identified within a forensic memory capture based on how the human voice is detected via a microphone and encoded to a digital format using the sound card of your personal computer. This digital format is unencrypted whist processed in Random Access Memory (RAM before it is passed to the VoIP application for encryption and  transmission over the Internet. Similarly, an incoming encrypted VoIP call is decrypted by the VoIP application and passes through RAM unencrypted in order to be played via the speaker output.A series of controlled tests were undertaken whereby RAM captures were analysed for remnants of digital speech after a VoIP audio call with known conversation. The identification and analysis of digital speech from RAM attempts to construct an automatic process for the identification and subsequent reconstruction of the audio content of a VoIP call.

  3. Caracterización de la biomasa inactiva de Aspergillus niger O-5 como sorbente de Pb (II

    Directory of Open Access Journals (Sweden)

    Yusleydi Enamorado Horrutiner

    2011-01-01

    Full Text Available The inactive biomass of fungus Aspergillus niger O-5 obtained in Cuba was characterized as sorbent of Pb2+ by several structural analysis and others techniques. In addition, the biomass was studied for the separation / preconcentration of Pb2+ from aqueous solution. The maximum biosorption capacity was obtained for the contact time of 30 min and pH 5. The kinetic of sorption process occurred according to the model of Ho. The Freundlich or Langmuir models suitably described the experimental adsorption isotherms. The biomass can be used as sorbent for Pb2+ with a maximum capacity of 4.7 - 6.2 mg g-1. The pretreatment with NaOH solution improved its sorption capacity.

  4. Synthesis and characterization of Pt/AgVO{sub 3} nanowires for degradation of atrazine using visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Malkhasian, Aramice Y.S., E-mail: amalkhasian10@gmail.com

    2015-11-15

    A hydrothermal method was used to prepare β-AgVO{sub 3} nanowire, a photo-assisted deposition (PAD) method was used to prepare Pt/β-AgVO{sub 3} nanowires. β-AgVO{sub 3} and Pt/β-AgVO{sub 3} nanowires were characterized using XRD, BET, UV–Vis spectroscopy, Pl, TEM, and XPS techniques. The results reveal that platinum was present as platinum metal and it is well dispersed on the surface of β-AgVO{sub 3} nanowire. The photocatalytic degradation of atrazine under visible light irradiation was used to measure the photocatalytic performance of the β-AgVO{sub 3} and Pt/β-AgVO{sub 3} nanowires. The photocatalytic activity of Pt/β-AgVO{sub 3} nanowires have higher photocatalytic activity than β-AgVO{sub 3} nanowire. The reason for the high photocatalytic activity of Pt/β-AgVO{sub 3} nanowires may be due to the synergic effect between Pt and β-AgVO{sub 3}. - Highlights: • Pt/β-AgVO{sub 3} nanowires were successfully prepared. • By control weight percent of Pt photocatalytic activity can be controlled. • Pt/β-AgVO{sub 3} can complete oxidation of atrazine under visible light irradiation.

  5. Curvilinear VO(2):power output relationship in a ramp test in professional cyclists: possible association with blood hemoglobin concentration.

    Science.gov (United States)

    Lucía, Alejandro; Hoyos, Jesús; Santalla, Alfredo; Pérez, Margarita; Chicharro, José L

    2002-02-01

    The purpose of this study was to determine (1) if there exists an additional, nonlinear increase (DeltaVO(2)) in the oxygen uptake observed (VO2 (obs)) at the maximal power output reached during a ramp cycle ergometer test and that expected (VO2 (exp)) from the linear relationship between VO(2) and power output below the lactate threshold (LT) in professional riders, and (2) the relationship between DeltaVO(2) and possible explanatory mechanisms. Each of 12 professional cyclists (25 +/- 1 years; VO(2 max): 71.3 +/- 1.2 ml x kg(-1) x min(-1)) performed a ramp test until exhaustion (power output increases of 25 W x min(-1)) during which several gas-exchange and blood variables were measured (including lactate, HCO(3)(-) and K(+)). VO(2) was linearly related to power output until the LT in all subjects. Afterward, a nonlinear deflection was observed in the VO(2):power output relationship (DeltaVO(2) = 2492 +/- 55 ml x min(-1) and p < 0.05 for VO2 (obs) vs. VO2 (exp)). A significant negative correlation was encountered between DeltaVO(2) and resting hemoglobin levels before the tests (r = 20.61; p < 0.05). In conclusion, professional cyclists exhibit an attenuation of the VO(2) rise above the LT.

  6. DynAstVO : the Europlanet orbital asteroid database

    Science.gov (United States)

    Desmars, Josselin; Thuillot, William; Hestroffer, Daniel J.; David, Pedro

    2016-10-01

    DynAstVO is a new orbital database dedicated to Near Earth Asteroid orbits, developed within the Europlanet 2020 RI framework.It provides parameters of asteroid orbits: orbital elements, observational information, minimum distance with Earth and planets, ephemeris and in particular, orbit uncertainty and associated covariance matrix.This database is updated daily on the basis of the Minor Planet Electronic Circulars.Orbit determination and improvement is computed as soon as new observations are available or an object is discovered.This database conforms to EPN-TAP environment (Erard et al. 2015, A&C 7) and is accessible through VO protocols or classical web access. Auxiliary data such as SPICE kernels for their ephemerides are provided.Finally, we present a comparison with other classical databases such as Astorb or MPCORB.Acknowledgements: This work is done in the framework of Europlanet 2020 RI which has received fundingfrom the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.

  7. Molecular Beam Optical Zeeman Spectroscopy of Vanadium Monoxide, VO

    Science.gov (United States)

    Nguyen, Trung; Zhang, Ruohan; Steimle, Timothy

    2016-06-01

    Like almost all astronomical studies, exoplanet investigations are observational endeavors that rely primarily on remote spectroscopic sensing to infer the physical properties of planets. Most exoplanet related information is inferred from to temporal variation of luminosity of the parent star. An effective method of monitoring this variation is via Magnetic Doppler Imaging (MDI), which uses optical polarimetry of paramagnetic molecules or atoms. One promising paramagnetic stellar absorption is the near infrared spectrum of VO. With this in mind, we have begun a project to record and analyze the field-free and Zeeman spectrum of the band. A cold (approx. 20 K) beam of VO was probed with a single frequency laser and detected using laser induced fluorescence. The determined spectral parameters will be discussed and compared to those extracted from the analysis of a hot spectrum. Supported by the National Science Foundation under the Grant No. CHE-1265885. O. Kochukhov, N. Rusomarov, J. A. Valenti, H. C. Stempels, F. Snik, M. Rodenhuis, N. Piskunov, V. Makaganiuk, C. U. Keller and C. M. Johns-Krull, Astron. Astrophys. 574 (Pt. 2), A79/71-A79/12 (2015). S. V. Berdyugina, Astron. Soc. Pac. Conf. Ser. 437 (Solar Polarization 6), 219-235 (2011). S. V. Berdyugina, P. A. Braun, D. M. Fluri and S. K. Solanki, Astron. Astrophys. 444 (3), 947-960 (2005). A. S. C. Cheung, P. G. Hajigeorgiou, G. Huang, S. Z. Huang and A. J. Merer, J. Mol. Spectrosc. 163 (2), 443-458 (1994)

  8. Mel-cepstrum-based steganalysis for VoIP steganography

    Science.gov (United States)

    Kraetzer, Christian; Dittmann, Jana

    2007-02-01

    Steganography and steganalysis in VoIP applications are important research topics as speech data is an appropriate cover to hide messages or comprehensive documents. In our paper we introduce a Mel-cepstrum based analysis known from speaker and speech recognition to perform a detection of embedded hidden messages. In particular we combine known and established audio steganalysis features with the features derived from Melcepstrum based analysis for an investigation on the improvement of the detection performance. Our main focus considers the application environment of VoIP-steganography scenarios. The evaluation of the enhanced feature space is performed for classical steganographic as well as for watermarking algorithms. With this strategy we show how general forensic approaches can detect information hiding techniques in the field of hidden communication as well as for DRM applications. For the later the detection of the presence of a potential watermark in a specific feature space can lead to new attacks or to a better design of the watermarking pattern. Following that the usefulness of Mel-cepstrum domain based features for detection is discussed in detail.

  9. AstroStat - A VO Tool for Statistical Analysis

    CERN Document Server

    Kembhavi, Ajit K; Kale, Tejas; Jagade, Santosh; Vibhute, Ajay; Garg, Prerak; Vaghmare, Kaustubh; Navelkar, Sharmad; Agrawal, Tushar; Nandrekar, Deoyani; Shaikh, Mohasin

    2015-01-01

    AstroStat is an easy-to-use tool for performing statistical analysis on data. It has been designed to be compatible with Virtual Observatory (VO) standards thus enabling it to become an integral part of the currently available collection of VO tools. A user can load data in a variety of formats into AstroStat and perform various statistical tests using a menu driven interface. Behind the scenes, all analysis is done using the public domain statistical software - R and the output returned is presented in a neatly formatted form to the user. The analyses performable include exploratory tests, visualizations, distribution fitting, correlation & causation, hypothesis testing, multivariate analysis and clustering. The tool is available in two versions with identical interface and features - as a web service that can be run using any standard browser and as an offline application. AstroStat will provide an easy-to-use interface which can allow for both fetching data and performing power statistical analysis on ...

  10. 基于WLAN的VoIP终端移动性管理研究%Research on Terminal Mobility Management for VoIP Based on WLAN

    Institute of Scientific and Technical Information of China (English)

    蒋青; 鲁艳

    2007-01-01

    目前,随着WLAN的发展,VoIP(Voice over Internet Protocol)技术在其中的应用也越来越广泛.但VoWLAN仍然面临着移动终端切换时延过长、话音容量低、安全隐患以及QoS保证等技术上的挑战.文章简要介绍了VoIP技术,重点研究了VoWLAN终端的移动性管理,在现有支持移动性管理协议的基础上,融合各层协议提出了一种改进的移动性管理新方案.

  11. Lotus tenuis Seedling Establishment and Biomass Production in Flooding Pampa Grasslands (Buenos Aires , Argentina Establecimiento de Plántulas y Producción de Biomasa de Lotus tenuis en Pastizales de la Pampa Deprimida (Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    Osvaldo R Vignolio

    2011-03-01

    Full Text Available Biomass and plant density of Lotus tenuis Waldst. & Kit. ex Willd. have been reported in decreasing in grasslands and pastures. Our objective was to determine if L. tenuis biomass and plant density can be increased in grassland through seed addition. Two separated experiments under cattle grazing exclusion were conducted in three paddocks of a Flooding Pampa grassland. The first experiment was from autumn 2004 to autumn 2006 and the second from autumn 2005 to autumn 2007. Different L. tenuis seed additions (0, 57, 229, 917 and 1833 seeds m-² were broadcast into experimental plots. In the second experiment, besides seed additions there was a reseeding of approximately 900 seed m-² from seed rain produced by plants of grassland. Seed density explained the 81% and 19% of the variation in seedling density and L. tenuis biomass, respectively. Seedling emergence occurred mainly between autumn and early spring, while seedling mortality was mainly between late spring and early summer. Lotus tenuis adult plant density and biomass production increased with seed additions. Total biomass production in the plant community varied between 589.94 ± 26.89 and 1042.44 ± 54.39 g m-² yr-1 and the differences were principally attributed to precipitations. Lotus tenuis biomass contribution was of approximately 10%. The results suggest that L. tenuis seedling and plant establishment and biomass production can be increased through seed addition and/or seed rain through grazing exclusion during reproductive period.En pastizales y pasturas ha sido documentada la reducción de la densidad de plantas y de la biomasa de Lotus tenuis Waldst. & Kit. ex Willd. Nuestro objetivo fue determinar si su densidad de plantas y su producción de biomasa pueden ser incrementadas en un pastizal mediante la adición de semillas. Dos experimentos sin pastoreo fueron realizados en tres potreros de un pastizal de la Pampa Deprimida. El primer experimento fue realizado entre otoño 2004

  12. Effect of Toe Clips During Bicycle Ergometry on VO2 max.

    Science.gov (United States)

    Moffat, Roger S.; Sparling, Phillip B.

    1985-01-01

    Eight men participated in three randomized maximal oxygen uptake tests to investigate the hypothesis that the use of toe clips on bicycle ergometers produced a higher VO2 max. No significant difference in mean VO2 max or performance time was observed. (Author/MT)

  13. Body fat, abdominal fat and body fat distribution related to VO(2PEAK) in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per; Karlsson, Magnus K

    2011-01-01

    as a percentage of body mass (BF%) and body fat distribution as AFM/TBF. VO(2PEAK) was assessed by indirect calorimetry during maximal exercise test. Results. Significant relationships existed between body fat measurements and VO(2PEAK) in both boys and girls, with Pearson correlation coefficients for absolute...

  14. On Tuning the Knobs of Distribution-Based Methods for Detecting VoIP Covert Channels

    Science.gov (United States)

    2012-01-04

    for use, because of the high bandwidth provided by the channels. However, Huang et al. [16] present a VoIP covert channel using steganography that...approximation theory. In Proc. of 49th IEEE FOCS, 2008. [16] Y F Huang, S Tang, and J Yuan. Steganography in inactive frames of VoIP streams encoded by

  15. Epitaxial growth of higher transition-temperature VO2 films on AlN/Si

    Directory of Open Access Journals (Sweden)

    Tetiana Slusar

    2016-02-01

    Full Text Available We report the epitaxial growth and the mechanism of a higher temperature insulator-to-metal-transition (IMT of vanadium dioxide (VO2 thin films synthesized on aluminum nitride (AlN/Si (111 substrates by a pulsed-laser-deposition method; the IMT temperature is TIMT ≈ 350 K. X-ray diffractometer and high resolution transmission electron microscope data show that the epitaxial relationship of VO2 and AlN is VO2 (010 ‖ AlN (0001 with VO2 [101] ‖   AlN   [ 2 1 ̄ 1 ̄ 0 ] zone axes, which results in a substrate-induced tensile strain along the in-plane a and c axes of the insulating monoclinic VO2. This strain stabilizes the insulating phase of VO2 and raises TIMT for 10 K higher than TIMT single crystal ≈ 340 K in a bulk VO2 single crystal. Near TIMT, a resistance change of about four orders is observed in a thick film of ∼130 nm. The VO2/AlN/Si heterostructures are promising for the development of integrated IMT-Si technology, including thermal switchers, transistors, and other applications.

  16. Crystal Structure and Spectroscopic Properties of CsVO2SO4

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Boghosian, S.; Nielsen, Kurt;

    2004-01-01

    in the range 1.725(1)-1.984(2) Angstrom. The deformation of the VO6 octahedron is thus much more pronounced compared to other known oxo sulfato V(V) compounds, and the coordination polyhedron of V(V) should be regarded as a tetragonal pyramid with the vanadium atom in the center. Each VO2+ group is coordinated...

  17. Infrared Thermochromic Properties of VO2 Thin Films Prepared through Aqueous Sol-gel Process

    Institute of Scientific and Technical Information of China (English)

    LIU Dongqing; CHENG Haifeng; ZHENG Wenwei; ZHANG Chaoyang

    2012-01-01

    The stoichiometric vanadium(Ⅳ) oxide thin films were obtained by controlling the temperature,time and pressure of annealing.The thermochromic phase transition and the IR thermochromic property of 400 nm and 900 nm VO2 thin films in the 7.5 μm-14 μm region were discussed.The derived VO2 thin film samples were characterized by Raman,XRD,XPS,AFM,SEM,and DSC.The resistance and infrared emissivity of VO2 thin films under different temperature were measured,and the thermal images of films were obtained using infrared imager.The results show that the VO2 thin film annealed at 550 ℃ for 10 hours through aqueous sol-gel process is pure and uniform.The 900 nm VO2 thin film exhibits better IR thermochromic property than the 400 nm VO2 thin film.The resistance of 900 nm VO2 film can change by 4orders of magnitude and the emissivity can change by 0.6 during the phase transition,suggesting the outstanding IR thermochromic property.The derived VO2 thin film can control its infrared radiation intensity and lower its apparent temperature actively when the real temperature increases,which may be applied in the field of energy saving,thermal control and camouflage.

  18. Non-Exercise Estimation of VO[subscript 2]max Using the International Physical Activity Questionnaire

    Science.gov (United States)

    Schembre, Susan M.; Riebe, Deborah A.

    2011-01-01

    Non-exercise equations developed from self-reported physical activity can estimate maximal oxygen uptake (VO[subscript 2]max) as well as sub-maximal exercise testing. The International Physical Activity Questionnaire is the most widely used and validated self-report measure of physical activity. This study aimed to develop and test a VO[subscript…

  19. Removing the thermal component from heart rate provides an accurate VO2 estimation in forest work.

    Science.gov (United States)

    Dubé, Philippe-Antoine; Imbeau, Daniel; Dubeau, Denise; Lebel, Luc; Kolus, Ahmet

    2016-05-01

    Heart rate (HR) was monitored continuously in 41 forest workers performing brushcutting or tree planting work. 10-min seated rest periods were imposed during the workday to estimate the HR thermal component (ΔHRT) per Vogt et al. (1970, 1973). VO2 was measured using a portable gas analyzer during a morning submaximal step-test conducted at the work site, during a work bout over the course of the day (range: 9-74 min), and during an ensuing 10-min rest pause taken at the worksite. The VO2 estimated, from measured HR and from corrected HR (thermal component removed), were compared to VO2 measured during work and rest. Varied levels of HR thermal component (ΔHRTavg range: 0-38 bpm) originating from a wide range of ambient thermal conditions, thermal clothing insulation worn, and physical load exerted during work were observed. Using raw HR significantly overestimated measured work VO2 by 30% on average (range: 1%-64%). 74% of VO2 prediction error variance was explained by the HR thermal component. VO2 estimated from corrected HR, was not statistically different from measured VO2. Work VO2 can be estimated accurately in the presence of thermal stress using Vogt et al.'s method, which can be implemented easily by the practitioner with inexpensive instruments.

  20. Nanostructured MoS2/BiVO4 Composites for Energy Storage Applications

    Science.gov (United States)

    Arora, Yukti; Shah, Amit P.; Battu, Shateesh; Maliakkal, Carina B.; Haram, Santosh; Bhattacharya, Arnab; Khushalani, Deepa

    2016-11-01

    We report the optimized synthesis and electrochemical characterization of a composite of few-layered nanostructured MoS2 along with an electroactive metal oxide BiVO4. In comparison to pristine BiVO4, and a composite of graphene/BiVO4, the MoS2/BiVO4 nanocomposite provides impressive values of charge storage with longer discharge times and improved cycling stability. Specific capacitance values of 610 Fg‑1 (170 mAhg‑1) at 1 Ag‑1 and 166 Fg‑1 (46 mAhg‑1) at 10 Ag‑1 were obtained for just 2.5 wt% MoS2 loaded BiVO4. The results suggest that the explicitly synthesized small lateral-dimensioned MoS2 particles provide a notable capacitive component that helps augment the specific capacitance. We discuss the optimized synthesis of monoclinic BiVO4, and few-layered nanostructured MoS2. We report the discharge capacities and cycling performance of the MoS2/BiVO4 nanocomposite using an aqueous electrolyte. The data obtained shows the MoS2/BiVO4 nanocomposite to be a promising candidate for supercapacitor energy storage applications.

  1. VoIP interconnection ; between Internet, Cable, Mobile and Fixed Worlds

    NARCIS (Netherlands)

    Deventer, M.O. van; Keesmaat, I.

    2005-01-01

    Four worlds on their own that hardly interconnect; All use SIP, but differently - Internet world - Mobile world - Cable world - Fixed world - At most, only basic voice service will interoperate between those worlds In recent years, VoIP/multimedia services (VoIP: Voice over Internet Protocol) have d

  2. Investigation of VO-Zni native donor complex in MBE grown bulk ZnO

    Science.gov (United States)

    Asghar, M.; Mahmood, K.; Ferguson, I. T.; Raja, M. Yasin A.; Xie, Y. H.; Tsu, R.; Hasan, M.-A.

    2013-10-01

    In this paper, we have experimentally investigated the theoretical predictions of VO-Zni to be a native donor in ZnO. Intrinsically zinc-rich n-type ZnO thin films having ND ˜ 6.23 × 1018 cm-3 grown by molecular beam epitaxy on Si (0 0 1) substrate were annealed in oxygen environment at 500-800 °C, keeping a step of 100 °C for 1 h, each. Room temperature Hall measurements demonstrated that free donor (VO-Zni) concentration decreased exponentially and Arrhenius plot yielded activation energy to be 1.2 ± 0.01 eV. This value is in agreement with theoretically reported activation energy of VO-Zni donor complex in ZnO. We argue; this observation can be explained by two-step process: (i) incoming oxygen fills VO of VO-Zni complex leaving behind Zni; (ii) Zni releases its energy and moves to a lower energy state with respect to the conduction band minima and/or occupies an inactive location. Consequently, Zni-VO complex loses its donor role in the lattice. Our experimental data supported theoretical predictions of VO-Zni to be a native donor. Results from photoluminescence spectroscopy carried out on Zn-rich ZnO additionally justify the existence of VO-Zni complex.

  3. A Voice Priority Queue (VPQ Fair Scheduler for the VoIP over WLANs

    Directory of Open Access Journals (Sweden)

    Kashif Nisar

    2011-02-01

    Full Text Available Transmission of VoIP over packet switching networks is one of the rapidly emerging real-time Internet Protocol. The real-time application of the Voice over Internet Protocol (VoIP is growing rapidly for it is more flexible than the traditional Public Switched Telephone Networks systems (PSTN. Meanwhile, the VoIP deployment on Wireless Local Area Networks (WLANs, which is based on IEEE 802.11 standards, is increasing. Currently, many schedulers have been introduced such as Weighted Fair Queueing (WFQ, Strict Priority (SP General processor sharing (GPS, Deficit Round Robin (DRR, andContention-Aware Temporally fair Scheduling (CATS. Unfortunately, the current scheduling techniques have some drawbacks on real-time applications and therefore will not be able to handle the VoIP packetsin a proper way. The objective of this research is to propose a new scheduler system model for the VoIP application named Voice Priority Queue (VPQ scheduler. The scheduler system model is to ensureefficiency by producing a higher throughput and fairness for VoIP packets. In this paper, only the First Stage of the VPQ packet scheduler and its algorithm are presented. Simulation topologies for VoIP traffic were implemented and analyzed using the Network Simulator (NS-2. The results show that this method can achieve a better and more accurate VoIP quality throughput and fairness index.

  4. VO2 Kinetics and Metabolic Contributions Whilst Swimming at 95, 100, and 105% of the Velocity at VO2 max

    Directory of Open Access Journals (Sweden)

    Ana C. Sousa

    2014-01-01

    Full Text Available A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transient VO2 kinetics responses and metabolic contributions whilst swimming at different velocities around VO2max⁡. 12 trained male swimmers performed (i an incremental protocol to determine the velocity at VO2max⁡ (vVO2max⁡ and (ii three square wave exercises from rest to 95, 100, and 105% of vVO2max⁡. VO2 was directly measured using a telemetric portable gas analyser and its kinetics analysed through a double-exponential model. Metabolic contributions were assessed through the sum of three energy components. No differences were observed in the fast component response (τ1—15, 18, and 16 s, A1—36, 34, and 37 mL·kg-1·min⁡-1, and Gain—32, 29, and 30 mL·min⁡-1 at 95, 100, and 105% of the vVO2max⁡, resp. but A2 was higher in 95 and 100% compared to 105% intensity (480.76 ± 247.01, 452.18 ± 217.04, and 147.04 ± 60.40 mL·min⁡-1, resp.. The aerobic energy contribution increased with the time sustained (83 ± 5, 74 ± 6, and 59 ± 7% for 95, 100, and 105%, resp.. The adjustment of the cardiovascular and/or pulmonary systems that determine O2 delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception of VO2 slow component kinetics metabolic profiles.

  5. Biomasa microbiana y actividad ureasa del suelo en una pradera permanente pastoreada de Chile Soil microbial biomass and urease activity in a grazed permanent pasture from Chile

    Directory of Open Access Journals (Sweden)

    Pedro Antonio Núñez Ramos

    2012-12-01

    Full Text Available En los sistemas de pasturas; la productividad de la pradera puede estar influenciada por el manejo; debido a su impacto sobre los microorganismos del suelo y el reciclaje de nutrientes. El objetivo de este trabajo fue evaluar la biomasa microbiana (BM del suelo asociada al nitrógeno (BMN; carbono (BMC y la actividad ureasa (AU en una pradera permanente del sur de Chile. Entre la primavera de 2005 y el invierno de 2006 fueron evaluados dos sistemas de pastoreo: pastoreo intenso (PI; pastoreo suave (PS y un tratamiento control (C. El diseño fue en bloques al azar con tres repeticiones. En relación a los valores promedios medidos de las variables en pre y post pastoreo; se produjo un incremento en los contenidos de CB en un 21,8 y 8,6% para PI y PS; mientras que en el control fue sólo de 1,9%. Los contenidos de NB también fueron incrementados en un 16 y 19% para PI y PS; respectivamente en comparación con el control (4%. La actividad ureasa aumentó en 13 y 27% para PI y PS; respectivamente en comparación con el control (5%. El pastoreo; produce un flujo más alto de residuos orgánicos en el suelo; lo que estimula la actividad de la biomasa microbiana y; por tanto; aumentó la AU y los contenidos de CB y NB. Esto sugiere que; en los sistemas de pastoreo; se mejora la fertilidad biológica de los suelos y la disponibilidad de nutrientes.In pasture systems, management practices can affect pasture productivity differently due to their impact on soil microorganisms and nutrient cycling. The objective of this study was to evaluate the relationship between soil microbial biomass (MB nitrogen (MBN, carbon (MBC and urease activity (UA in a permanent pasture in southern Chile. Two grazing systems were evaluated between spring 2005 and winter 2006 : heavy grazing (HG, light grazing (LG and a control treatment (C. Treatments were arranged in a randomized block design with three replications. Concerning the average values of the variables measured at

  6. DESEMPEÑO PRODUCTIVO DE POLLOS DE ENGORDE SUPLEMENTADOS CON BIOMASA DE Saccharomyces cerevisiae DERIVADA DE LA FERMENTACIÓN DE RESIDUOS DE BANANO

    Directory of Open Access Journals (Sweden)

    N. M. Medina

    2014-01-01

    Full Text Available El objetivo de esta investigación fue evaluar el efecto de la inclusión de diferentes ni-veles de biomasa de levaduras, producidos al fermentar hidrolizados de residuos de laindustria bananera, sobre los parámetros zootécnicos de pollos de engorde, evaluandoademás el impacto económico de su uso en las dietas. Se utilizaron 210 pollos de en-gorde de un día de edad, distribuidos completamente al azar en cinco tratamientos,en una relación de seis réplicas por tratamiento y siete pollos por réplica. El periodoexperimental comprendió 42 días; el alimento y el agua se dispensaron a voluntad. Lasdietas experimentales fueron: T1- Control negativo sin levadura, T2- Control positivocon levadura comercial a razón de 1,5 kg ton-1de alimento, T3- Levadura experimentala razón de 0,5 kg ton-1de la dieta, T4-Levadura experimental a razón de 1,0 kg ton-1de la dieta y T5- Levadura experimental a razón de 1,5 kg ton-1de la dieta. Se observómayor consumo de acumulado alimento en el tratamiento 4 (1kg ton-1de levadura conrespecto a los demás tratamientos evaluados. No hubo diferencias significativas (P>0.05en las otras variables evaluadas en el estudio. Se constató beneficio económico con el usodel tratamiento 4 pues se obtuvieron mejores retornos (precio de venta del pollo – costode la alimentación que fueron mayores a los observados en los tratamientos 1, 2, 3 y 5en 153, 82, 62 y 161 pesos($ ave-1, respectivamente.

  7. A new non-exercise-based Vo2max prediction equation for aerobically trained men.

    Science.gov (United States)

    Malek, Moh H; Housh, Terry J; Berger, Dale E; Coburn, Jared W; Beck, Travis W

    2005-08-01

    The purposes of the present study were to (a) modify previously published Vo(2)max equations using the constant error (CE = mean difference between actual and predicted Vo(2)max) values from Malek et al. (28); (b) cross-validate the modified equations to determine their accuracy for estimating Vo(2)max in aerobically trained men; (c) derive a new non- exercise-based equation for estimating Vo(2)max in aerobically trained men if the modified equations are not found to be accurate; and (d) cross-validate the new Vo(2)max equation using the predicted residual sum of squares (PRESS) statistic and an independent sample of aerobically trained men. One hundred and fifty-two aerobically trained men (Vo(2)max mean +/- SD = 4,154 +/- 629 ml.min(-1)) performed a maximal incremental test on a cycle ergometer to determine actual Vo(2)max. An aerobically trained man was defined as someone who had participated in continuous aerobic exercise 3 or more sessions per week for a minimum of 1 hour per session for at least the past 18 months. Nine previously published Vo(2)max equations were modified for use with aerobically trained men. The predicted Vo(2)max values from the 9 modified equations were compared to actual Vo(2)max by examining the CE, standard error of estimate (SEE), validity coefficient (r), and total error (TE). Cross-validation of the modified non-exercise-based equations on a random subsample of 50 subjects resulted in a %TE > or = 13% of the mean of actual Vo(2)max. Therefore, the following non-exercise-based Vo(2)max equation was derived from a random subsample of 112 subjects: Vo(2)max (ml.min(-1)) = 27.387(weight in kg) + 26.634(height in cm) - 27.572(age in years) + 26.161(h.wk(-1) of training) + 114.904(intensity of training using the Borg 6-20 scale) + 506.752(natural log of years of training) - 4,609.791 (R = 0.82, R(2) adjusted = 0.65, and SEE = 378 ml.min(-1)). Cross-validation of this equation on the remaining sample of 40 subjects resulted in a %TE of 10

  8. Influence of Heat Treatment on Photocatalytic Performance of BiVO4 Synthesized by Hydrothermal Method

    Science.gov (United States)

    Shen, Yi; Wang, Xiaomin; Zuo, Guifu; Li, Fengfeng; Meng, Yanzhi

    2016-10-01

    Monoclinic BiVO4 photocatalyst was successfully synthesized by hydrothermal method under appropriate temperature. The photocatalytic performance of BiVO4 was improved by calcining at appropriate temperature. The structural and morphological properties of the synthesized BiVO4 photocatalysts were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. It is confirmed that the photocatalytic activity of the prepared catalysts was evaluated by the photodegradation of RhB under visible-light irradiation. BiVO4 calcined under appropriate temperature exhibited higher photocatalytic activity than uncalcined BiVO4 under visible light irradiation because calcination might effectively increases the purity of monoclinic bismuth vanadate.

  9. Hydrothermal growth of VO2 nanoplate thermochromic films on glass with high visible transmittance

    Science.gov (United States)

    Zhang, Jiasong; Li, Jingbo; Chen, Pengwan; Rehman, Fida; Jiang, Yijie; Cao, Maosheng; Zhao, Yongjie; Jin, Haibo

    2016-06-01

    The preparation of thermochromic vanadium dioxide (VO2) films in an economical way is of interest to realizing the application of smart windows. Here, we reported a successful preparation of self-assembly VO2 nanoplate films on TiO2-buffered glass by a facile hydrothermal process. The VO2 films composed of triangle-shaped plates standing on substrates exhibit a self-generated porous structure, which favors the transmission of solar light. The porosity of films is easily controlled by changing the concentration of precursor solutions. Excellent thermochromic properties are observed with visible light transmittance as high as 70.3% and solar modulating efficiency up to 9.3% in a VO2 film with porosity of ~35.9%. This work demonstrates a promising technique to promote the commercial utilization of VO2 in smart windows.

  10. Study on VUV and UV Excitation Spectrum of GdVO4∶Eu3+

    Institute of Scientific and Technical Information of China (English)

    张庆礼; 郑丽秋; 郭常新; 施朝淑; 魏亚光; 戚泽明

    2001-01-01

    The photoluminescence spectra and excitation spectra in the vacuum ultraviolet (VUV) and ultraviolet (UV) spectra region of GdVO4∶Eu3+ were reported. The excitation and emission spectra indicate that GdVO4∶Eu3+ is a highly efficient phosphor for the excitation in the VUV and UV spectrum region. The excitation band in the VUV and UV spectrum region of 60~350 nm consists mainly of the absorption of host, which has obvious absorption of 4fn-15d of Eu3+ and Gd3+. In GdVO4∶Eu3+, there is the energy transfer: VO43-→Eu3+, Gd3+→Eu3+ and Gd3+→VO43-→Eu3+. Through the last two procedures, maybe the quantum cutting of Gd3+-Eu3+ occurs.

  11. Adsorption-controlled growth of BiVO4 by molecular-beam epitaxy

    Directory of Open Access Journals (Sweden)

    S. Stoughton

    2013-10-01

    Full Text Available Single-phase epitaxial films of the monoclinic polymorph of BiVO4 were synthesized by reactive molecular-beam epitaxy under adsorption-controlled conditions. The BiVO4 films were grown on (001 yttria-stabilized cubic zirconia (YSZ substrates. Four-circle x-ray diffraction, scanning transmission electron microscopy (STEM, and Raman spectroscopy confirm the epitaxial growth of monoclinic BiVO4 with an atomically abrupt interface and orientation relationship (001BiVO4 ∥ (001YSZ with [100]BiVO4 ∥ [100]YSZ. Spectroscopic ellipsometry, STEM electron energy loss spectroscopy (STEM-EELS, and x-ray absorption spectroscopy indicate that the films have a direct band gap of 2.5 ± 0.1 eV.

  12. Selective growth of single phase VO2(A, B, and M polymorph thin films

    Directory of Open Access Journals (Sweden)

    Amar Srivastava

    2015-02-01

    Full Text Available We demonstrate the growth of high quality single phase films of VO2(A, B, and M on SrTiO3 substrate by controlling the vanadium arrival rate (laser frequency and oxidation of the V atoms. A phase diagram has been developed (oxygen pressure versus laser frequency for various phases of VO2 and their electronic properties are investigated. VO2(A phase is insulating VO2(B phase is semi-metallic, and VO2(M phase exhibits a metal-insulator transition, corroborated by photo-electron spectroscopic studies. The ability to control the growth of various polymorphs opens up the possibility for novel (heterostructures promising new device functionalities.

  13. Voltage switching of a VO{sub 2} memory metasurface using ionic gel

    Energy Technology Data Exchange (ETDEWEB)

    Goldflam, M. D.; Liu, M. K.; Chapler, B. C.; Stinson, H. T.; Sternbach, A. J.; McLeod, A. S.; Basov, D. N., E-mail: dbasov@physics.ucsd.edu [Department of Physics, The University of California at San Diego, La Jolla, California 92093 (United States); Zhang, J. D.; Geng, K. [Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Royal, M.; Jokerst, N. M.; Smith, D. R. [Center for Metamaterials and Integrated Plasmonics, Pratt School of Engineering, Duke University, Durham, North Carolina 27708 (United States); Kim, Bong-Jun [Metal-Insulator Transition Creative Research Center, ETRI, Daejeon 305-350 (Korea, Republic of); Averitt, R. D. [Department of Physics, The University of California at San Diego, La Jolla, California 92093 (United States); Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Kim, H-T. [Metal-Insulator Transition Creative Research Center, ETRI, Daejeon 305-350 (Korea, Republic of); School of Advanced Device Technology, University of Science and Technology, Daejeon 305-333 (Korea, Republic of)

    2014-07-28

    We demonstrate an electrolyte-based voltage tunable vanadium dioxide (VO{sub 2}) memory metasurface. Large spatial scale, low voltage, non-volatile switching of terahertz (THz) metasurface resonances is achieved through voltage application using an ionic gel to drive the insulator-to-metal transition in an underlying VO{sub 2} layer. Positive and negative voltage application can selectively tune the metasurface resonance into the “off” or “on” state by pushing the VO{sub 2} into a more conductive or insulating regime respectively. Compared to graphene based control devices, the relatively long saturation time of resonance modification in VO{sub 2} based devices suggests that this voltage-induced switching originates primarily from electrochemical effects related to oxygen migration across the electrolyte–VO{sub 2} interface.

  14. Research on VoWLAN Terminal Based on FPGA%一种基于FPGA的VoWLAN终端研究

    Institute of Scientific and Technical Information of China (English)

    陶怡栋; 杜永文

    2011-01-01

    In this paper, the design based on Field Programmable Gate Array (FPGA) of wireless IP phone which can work in Wireless Fidelity (Wi-Fi) environment is proposed. The research includes designing Wi-Fi module, transplanting oRi200 soft core processor in FPGA using System-on-a-Programmable-Chip (SOPC) technology, transplanting embedded Linux operating system on OR1200, and finally designing the VolP application software.%在分析现有网络电话终端实现方式的基础上,提出了一种基于现场可编程门阵列(FPGA)且具有无线保真(wi—Fi)功能的无线网络电话终端(VoWLAN终端,基于无线局域网的语音通信终端)的设计方案。主要研究内容包括设计w1-Fi通信模块,利用可编程片上系统(sOPc)技术在FPGA上移植ORl200软核处理器,将嵌入式Linux操作系统移植到ORl200软核处理器上,最后设计出VoIP应用软件。

  15. Producción de biomasa verde y calidad de aceites esenciales de palmarosa (Cymbopogon martini Roxb. con aplicación de fertilizantes de síntesis y orgánicos

    Directory of Open Access Journals (Sweden)

    Javier Alberto Pinzón-Torres

    2014-12-01

    Full Text Available El uso de fertilizantes minerales en cultivos de Cymbopogon martini Roxb. (Palmarosa con el fin de incrementar la biomasa y el rendimiento de aceite esencial (AE es una práctica cada vez más frecuente. Este aceite es rico en geraniol y acetato de geranilo, moléculas con alto valor en las industrias de productos cosméticos y farmacéutica. Las plantas fueron obtenidas del Centro Nacional de Investigación Agroindustrial de Plantas Aromaticas y Medicinales de la Universidad Industrial de Santander (UIS (Cenivam (07° 08' 31.68"N, 73° 07' 06.14O; 988 m.s.n.m., Santander, Colombia. El objetivo del estudio fue evaluar la productividad de biomasa y analizar la calidad y el rendimiento de los aceites esenciales (AE de este cultivo con la aplicación de tres tipos de fertilizantes químico: Nutrimon® 14-14-14, NPK granulado (10% N, 14% P2O5 , 14% K2O, en dosis de 2, 4 y 6 g/planta, más un tratamiento con 400 g de un fertilizante orgánico,. Se utilizó un diseño de bloques completos al azar, con trece tratamientos y tres cosechas de tres plantas cada una como repeticiones. Los datos fueron sometidos a análisis de variancia con comparación de las medias por la prueba de Tukey a 5% de probabilidad. No se observaron correlaciones entre biomasa y rendimiento del AE en función del tipo del fertilizante aplicado, lo que sugirió que los tratamientos que incrementaron la producción de biomasa no necesariamente representaron mayor rendimiento del AE y viceversa. Se encontró que los fertilizantes orgánicos son ideales para este cultivo, ya que favorecieron rendimientos relativamente altos en aceite, con altos porcentajes de geraniol y acetato de geranilo.

  16. Abundancia y biomasa de organismos edáficos en tres usos del terreno en el altiplano de Pasto, Colombia Abundance and biomass of soil organisms in three land use systems in the high plateau of Pasto, Colombia

    Directory of Open Access Journals (Sweden)

    Jorge H. Castro P.

    Full Text Available La investigación se realizó en la vereda Cruz de Amarillo, municipio de Pasto (1º 7' norte y 77º 17´ oeste, 2.850 msnm, 12º C y humedad relativa del 83%. Se seleccionaron tres usos del terreno: praderas de Lollium multiflorum (ryegrass y Pennisetum clandestinum (kikuyo y un bosque secundario. En cada uno se trazó una línea recta y se tomaron ocho muestras, separadas 10 m, cada 15 días. El muestreo se hizo siguiendo la metodología del Tropical Soil Biology and Fertility Programe (TSBF. La fauna se recolectó manualmente y posteriormente se hizo el conteo y la valoración de la biomasa; los organismos se identificaron hasta nivel de familia y en algunos casos sólo hasta orden. También se determinó humedad gravimétrica, porosidad y contenido de materia orgánica. Los datos se analizaron de acuerdo con un diseño de bloques completos al azar. La pradera de L. multiflorum y el bosque secundario presentaron los mayores valores de abundancia de lombrices (5.648 y 4.864 ind m-2 y biomasa (141.3 y 670.7 g.p.f.m-2. En la pradera de P. clandestinum abundaron los ácaros (2.768 ind m-2 con una biomasa de 0.22 g. p. f m-2. En todos los usos del suelo la mayor abundancia de organismos y biomasa se presentó en la profundidad de 0 - 10 cm.At the county of Cruz de Amarillo, municipality of Pasto, Colombia , located al 2850 masl, a field study to determine the numbers of organisms and its biomass was carried out. Three land use systems were selected: prairie with the grass Lolium multiflorum (Ryegrass, pasture with Pennisetum clandestinum (kikuyu and secondary forest. The prairie of .L multiflorum and the secondary forest showed the highest values of abundance of earth worms (5648 and 4864 ind m-2, respectively. Biomass was 141.3 and 670.7 gpfm-2 for L. multiflorum and P. clandestinum, respectively. Mites were abundant (2768 ind m-2 with a biomass of 0.22 gpfm-2. At all land use systems, the highest abundance of organisms and biomass at 2 depth of

  17. Influencia de la proporción agua de mar y bicarbonato en la producción de biomasa de Spirulina sp. con iluminación de diodo emisor de luz

    Directory of Open Access Journals (Sweden)

    Víctor Vasquez-Villalobos

    2014-01-01

    Full Text Available Se estudió la influencia de las variables proporción agua de mar (% y concentración de bicarbonato en laproducción de biomasa deSpirulinasp., utilizándose un Diseño Compuesto Central Rotacional (DCCR paraevaluar las regiones óptimas de producción de biomasa (φ, fase de adaptación (λ velocidad específica decrecimiento (μ y tiempo de generación (G, empleándose en cada ensayo el modelo matemático de Gompertz.Se obtuvo el mayor valor de biomasa (φ log N/N0: 0,928 a las168,8 horas en un medio de cultivo con pH de8,8±0,1; a temperatura de 25ºC; con salinidad de 1,2% y 1,6g/L de bicarbonato. El menor valor de φ fue de0,45±0,01; obtenidocoincidentemente en las repeticiones del punto central, utilizando una salinidad de 0,7% y3,0g/L de bicarbonato en un medio con pH de 9,1±0,4 a 25ºC; lo que demuestra la importancia de la salinidadaportada por volumen de agua de mar en relación al bicarbonato, en la producción de biomasa deSpirulina. Lailuminación fue de 2,7±1,2 klx, proporcionada por un Diodo Emisor de Luz Blanca (DELB por 12 horascontinuas y con una inyección de 0,86±0,09 L/s de aire por fotobiorreactor de 200 mL de capacidad.Solamente los valores de φ se ajustaron adecuadamente a la Superficie de Respuesta con un R2de 0,99 para unmodelo matemático cuadrático y p<0,05, con un error absoluto medio de 2,4%.

  18. Plan técnico de mejoras en el rendimiento de la planta de biomasa para generación eléctrica; térmica AFAP S.A Villacañas (Toledo)

    OpenAIRE

    Paton Mancebo, Angel Hilario

    2014-01-01

    La planta Térmica AFAP S.A se dedica a la generación eléctrica procedente de la combustión de principalmente Biomasa forestal (madera de pino principalmente) y algo de residuos maderables de las fabricas de puertas que existen la localidad de Villacañas, municipio donde se encuentra ubicada dicha planta. El objeto de este proyecto es la mejora en el rendimiento y rentabilidad de dicha planta enfocado en varías líneas: -infraestructuras en la planta: instalación de Nave de almacenamiento para ...

  19. Photocatalytic and photoelectrochemical water oxidation over metal-doped monoclinic BiVO(4) photoanodes.

    Science.gov (United States)

    Parmar, Kanak Pal Singh; Kang, Hyun Joon; Bist, Amita; Dua, Piyush; Jang, Jum Suk; Lee, Jae Sung

    2012-10-01

    The visible-light-induced water oxidation ability of metal-ion-doped BiVO(4) was investigated and of 12 metal ion dopants tested, only W and Mo dramatically enhanced the water photo-oxidation activity of bare BiVO(4); Mo had the highest improvement by a factor of about six. Thus, BiVO(4) and W- or Mo-doped (2 atom %) BiVO(4) photoanodes about 1 μm thick were fabricated onto transparent conducting substrate by a metal-organic decomposition/spin-coating method. Under simulated one sun (air mass 1.5G, 100 mW cm(-2)) and at 1.23 V versus a reversible hydrogen electrode, the highest photocurrent density (J(PH)) of about 2.38 mA cm(-2) was achieved for Mo doping followed by W doping (J(PH) ≈ 1.98 mA cm(-2)), whereas undoped BiVO(4) gave a J(PH) value of about 0.42 mA cm(-2). The photoelectrochemical water oxidation activity of W- and Mo-doped BiVO(4) photoanodes corresponded to the incident photon to current conversion efficiency of about 35 and 40 % respectively. Electrochemical impedance spectroscopy and Mott-Schottky analysis indicated a positive flat band shift of about 30 mV, a carrier concentration 1.6-2 times higher, and a charge-transfer resistance reduced by 3-4-fold for W- or Mo-doped BiVO(4) relative to undoped BiVO(4). Electronic structure calculations revealed that both W and Mo were shallow donors and Mo doping generated superior conductivity to W doping. The photo-oxidation activity of water on BiVO(4) photoanodes (undopedphotocatalytic and photoelectrochemical water oxidation activity of monoclinic BiVO(4) by drastically reducing its charge-transfer resistance and thereby minimizing photoexcited electron-hole pair recombination.

  20. Synthesis and visible-light photocatalytic activity of NdVO{sub 4} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jing [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Chongqing University of Science and Technology, Chongqing 401331 (China); Hu Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Liu Gaobin [Department of Applied Physics, Chongqing University, Chongqing 400044 (China); Liu Hong; Du Guojun [State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Zhang Yan [Department of Applied Physics, Chongqing University, Chongqing 400044 (China)

    2011-07-28

    Graphical abstract: NdVO{sub 4} nanowires are synthesized by a simple composite molten salt method. The effective light absorption and photodegradation are found. Highlights: > We report the fabrication, characterization and photocatalytic activity of NdVO{sub 4} nanowires synthesized by the composite molten salt method. > The NdVO{sub 4} nanowires show effective light absorption and high catalytic degradation activity to Rhodamine B. > The electron density states of the NdVO{sub 4} were calculated with the Vienna ab initio simulation package, which explains the light absorption and photodegradation properties. - Abstract: NdVO{sub 4} nanowires are synthesized by a simple composite molten salt method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrum, energy dispersive spectrometry and UV-vis spectrum are used to characterize the structure, morphology and composition of the sample. The results show that the product is of tetragonal phase NdVO{sub 4} nanowires which are connected together in bases, rooted in one center, with typical diameters of 100 nm and lengths up to 3 {mu}m. The UV-vis spectrum shows that NdVO{sub 4} nanowires have four strong absorption peaks from the UV to near infrared region. The photocatalytic degradation of Rhodamine B (RhB) and methyl orange under visible light irradiation using the NdVO{sub 4} nanowires are also investigated. Excellent catalytic degradation activity of RhB observed suggests possible applications for organic pollutant treatment under visible light irradiation. The electron density states of the NdVO{sub 4} were calculated with the Vienna ab initio simulation package. The results of these simulations were used to form a description of the observed light absorption and photodegradation properties of NdVO{sub 4} nanowires.

  1. VO{sub 2} (A): Reinvestigation of crystal structure, phase transition and crystal growth mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Rao Popuri, Srinivasa [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France); National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Plautius Andronescu Str. No. 1, 300224 Timisoara (Romania); Artemenko, Alla [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France); Labrugere, Christine [CeCaMA, University of Bordeaux 1, ICMCB, 87 Avenue du Dr. A. Schweitzer, F-33608 Pessac (France); Miclau, Marinela [National Institute for Research and Development in Electrochemistry and Condensed Matter, Timisoara, Plautius Andronescu Str. No. 1, 300224 Timisoara (Romania); Villesuzanne, Antoine [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France); Pollet, Michaël, E-mail: pollet@icmcb-bordeaux.cnrs.fr [ICMCB, CNRS, UPR 9048, F-33608 Pessac (France); University of Bordeaux, ICMCB, UPR 9048, F-33608 Pessac (France)

    2014-05-01

    Well crystallized VO{sub 2} (A) microrods were grown via a single step hydrothermal reaction in the presence of V{sub 2}O{sub 5} and oxalic acid. With the advantage of high crystalline samples, we propose P4/ncc as an appropriate space group at room temperature. From morphological studies, we found that the oriented attachment and layer by layer growth mechanisms are responsible for the formation of VO{sub 2} (A) micro rods. The structural and electronic transitions in VO{sub 2} (A) are strongly first order in nature, and a marked difference between the structural transition temperatures and electronic transitions temperature was evidenced. The reversible intra- (LTP-A to HTP-A) and irreversible inter- (HTP-A to VO{sub 2} (M1)) structural phase transformations were studied by in-situ powder X-ray diffraction. Attempts to increase the size of the VO{sub 2} (A) microrods are presented and the possible formation steps for the flower-like morphologies of VO{sub 2} (M1) are described. - Graphical abstract: Using a single step and template free hydrothermal synthesis, well crystallized VO{sub 2} (A) microrods were prepared and the P4/ncc space group was assigned to the room temperature crystal structure. Reversible and irreversible phase transitions among different VO{sub 2} polymorphs were identified and their progressive nature was highlighted. Attempts to increase the microrods size, involving layer by layer formation mechanisms, are presented. - Highlights: • Highly crystallized VO{sub 2} (A) microrods were grown via a single step hydrothermal process. • The P4/ncc space group was determined for VO{sub 2} (A) at room temperature. • The electronic structure and progressive nature of the structural phase transition were investigated. • A weak coupling between structural and electronic phase transitions was identified. • Different crystallite morphologies were discussed in relation with growth mechanisms.

  2. Why is VO2 max after altitude acclimatization still reduced despite normalization of arterial O2 content?

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Radegran, G

    2003-01-01

    Acute hypoxia (AH) reduces maximal O2 consumption (VO2 max), but after acclimatization, and despite increases in both hemoglobin concentration and arterial O2 saturation that can normalize arterial O2 concentration ([O2]), VO2 max remains low. To determine why, seven lowlanders were studied at VO2...

  3. VoIP的发展及其应用

    Institute of Scientific and Technical Information of China (English)

    白华斌; 李哲

    2009-01-01

    VoIP即Voice Over IP,是把话音或传真转换成数据,然后与数据一起共享同一个IP网络(Internet互联网)。由于话音和传真在Internet上免费搭乘了“顺风车”,所以点对点(网关一一网关)国际或国内长途通讯是完全免费的。IP网络可以是Internet、IPLC(国际专线)、无线网络等,只要是采用IP协议(Internet Protocol)就可以了。

  4. A structured approach to VO reconfigurations through Policies

    Directory of Open Access Journals (Sweden)

    Stephan Reiff-Marganiec

    2012-04-01

    Full Text Available One of the strength of Virtual Organisations is their ability to dynamically and rapidly adapt in response to changing environmental conditions. Dynamic adaptability has been studied in other system areas as well and system management through policies has crystallized itself as a very prominent solution in system and network administration. However, these areas are often concerned with very low-level technical aspects. Previous work on the APPEL policy language has been aimed at dynamically adapting system behaviour to satisfy end-user demands and – as part of STPOWLA – APPEL was used to adapt workflow instances at runtime. In this paper we explore how the ideas of APPEL and STPOWLA can be extended from workflows to the wider scope of Virtual Organisations. We will use a Travel Booking VO as example.

  5. A structured approach to VO reconfigurations through Policies

    CERN Document Server

    Reiff-Marganiec, Stephan

    2012-01-01

    One of the strength of Virtual Organisations is their ability to dynamically and rapidly adapt in response to changing environmental conditions. Dynamic adaptability has been studied in other system areas as well and system management through policies has crystallized itself as a very prominent solution in system and network administration. However, these areas are often concerned with very low-level technical aspects. Previous work on the APPEL policy language has been aimed at dynamically adapting system behaviour to satisfy end-user demands and - as part of STPOWLA - APPEL was used to adapt workflow instances at runtime. In this paper we explore how the ideas of APPEL and STPOWLA can be extended from workflows to the wider scope of Virtual Organisations. We will use a Travel Booking VO as example.

  6. WE-MQS-VoIP Priority: An enhanced LTE Downlink Scheduler for voice services with the integration of VoIP priority mode

    Directory of Open Access Journals (Sweden)

    Duy-Huy Nguyen

    2016-07-01

    Full Text Available The Long Term Evolution (LTE is a high data rates and fully All-IP network. It is developed to support well to multimedia services such as Video, VoIP, Gaming, etc. So that, the real-time services such as VoIP, video, etc. need to be optimized. Nevertheless, the deployment of such live stream services having many challenges. Scheduling and allocating radio resource are very important in LTE network, especially with multimedia services such as VoIP. When voice service transmitted over LTE network, it is affected by many network impairments where there are three main factors including packet loss, delay, and jitter. This study proposes a new scheduler which is based on VoIP priority mode,Wideband (WB E-model, QoS- and Channel-Aware (called WE-MQS-VoIP Priority scheduler for voice services in LTE downlink direction. The proposed scheduling scheme is built based on the WB E-model and Maximum Queue Size (MQS. In addition, we integrate the VoIP priority mode into our scheduling scheme. Since the proposed scheduler considers the VoIP priority mode and user perception, thus, it improves significantly the system performance. The results demonstrate that the proposed scheduler not only meets QoS demands of voice calls but also outperforms Modified Largest Weighted Delay First (M-LWDF in terms of delay, Packet Loss Rate (PLR for all number of user (NU and excepting NU equals 30, respectively. For Fairness Index (FI, cell throughput, and Spectral Efficiency (SE, the difference among the packet schedulers is not significant. The performance evaluation is compared in terms of Delay, PLR, Throughput, FI, and SE.

  7. Efficient solar-driven water splitting by nanocone BiVO4-perovskite tandem cells

    Science.gov (United States)

    Qiu, Yongcai; Liu, Wei; Chen, Wei; Chen, Wei; Zhou, Guangmin; Hsu, Po-Chun; Zhang, Rufan; Liang, Zheng; Fan, Shoushan; Zhang, Yuegang; Cui, Yi

    2016-01-01

    Bismuth vanadate (BiVO4) has been widely regarded as a promising photoanode material for photoelectrochemical (PEC) water splitting because of its low cost, its high stability against photocorrosion, and its relatively narrow band gap of 2.4 eV. However, the achieved performance of the BiVO4 photoanode remains unsatisfactory to date because its short carrier diffusion length restricts the total thickness of the BiVO4 film required for sufficient light absorption. We addressed the issue by deposition of nanoporous Mo-doped BiVO4 (Mo:BiVO4) on an engineered cone-shaped nanostructure, in which the Mo:BiVO4 layer with a larger effective thickness maintains highly efficient charge separation and high light absorption capability, which can be further enhanced by multiple light scattering in the nanocone structure. As a result, the nanocone/Mo:BiVO4/Fe(Ni)OOH photoanode exhibits a high water-splitting photocurrent of 5.82 ± 0.36 mA cm−2 at 1.23 V versus the reversible hydrogen electrode under 1-sun illumination. We also demonstrate that the PEC cell in tandem with a single perovskite solar cell exhibits unassisted water splitting with a solar-to-hydrogen conversion efficiency of up to 6.2%. PMID:27386565

  8. Efficient solar-driven water splitting by nanocone BiVO4-perovskite tandem cells.

    Science.gov (United States)

    Qiu, Yongcai; Liu, Wei; Chen, Wei; Chen, Wei; Zhou, Guangmin; Hsu, Po-Chun; Zhang, Rufan; Liang, Zheng; Fan, Shoushan; Zhang, Yuegang; Cui, Yi

    2016-06-01

    Bismuth vanadate (BiVO4) has been widely regarded as a promising photoanode material for photoelectrochemical (PEC) water splitting because of its low cost, its high stability against photocorrosion, and its relatively narrow band gap of 2.4 eV. However, the achieved performance of the BiVO4 photoanode remains unsatisfactory to date because its short carrier diffusion length restricts the total thickness of the BiVO4 film required for sufficient light absorption. We addressed the issue by deposition of nanoporous Mo-doped BiVO4 (Mo:BiVO4) on an engineered cone-shaped nanostructure, in which the Mo:BiVO4 layer with a larger effective thickness maintains highly efficient charge separation and high light absorption capability, which can be further enhanced by multiple light scattering in the nanocone structure. As a result, the nanocone/Mo:BiVO4/Fe(Ni)OOH photoanode exhibits a high water-splitting photocurrent of 5.82 ± 0.36 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode under 1-sun illumination. We also demonstrate that the PEC cell in tandem with a single perovskite solar cell exhibits unassisted water splitting with a solar-to-hydrogen conversion efficiency of up to 6.2%.

  9. Synthesis and photocatalytic performances of BiVO 4 by ammonia co-precipitation process

    Science.gov (United States)

    Yu, Jianqiang; Zhang, Yan; Kudo, Akihiko

    2009-02-01

    This paper reports the preparation and photocatalytic performance of Bismuth vanadate (BiVO 4) by a facile and inexpensive approach. An amorphous BiVO 4 was first prepared by a co-precipitation process from aqueous solutions of Bi(NO 3) 3 and NH 4VO 3 using ammonia. Followed by heating treatment at various temperatures, the amorphous phase converted to crystalline BiVO 4 with a structure between monoclinic and tetragonal scheelite. The crystallization of BiVO 4 occurred at about 523 K, while the nanocrystalline BiVO 4 were formed with a heat-treatment of lower than 673 K. However, when the heat-treatment was carried out at 773 K, the accumulation of nanocrystals to bulk particles was observed. The photocatalytic performances of the materials were investigated by O 2 evolution under visible-light, and MB decomposition under solar simulator. The results demonstrated that the crystalline structure is still the vital factor for the activities of both reactions. However, the crystallinity of BiVO 4 gives a major influence on the activity of O 2 evolution, whereas the surface area, plays an important role for photocatalytic MB decomposition.

  10. A theoretical analysis of factors determining VO2 MAX at sea level and altitude.

    Science.gov (United States)

    Wagner, P D

    1996-12-01

    When maximal VO2 (VO2 MAX) is limited by O2 supply, it is generally thought that cardiac output (QT) is mostly responsible, but other O2 transport conductances [ventilation (VA); [Hb]; pulmonary (DLO2) and muscle (DMO2) diffusion capacities] may also influence VO2 MAX. A numerical analysis interactively linking the lungs, circulation and muscles was designed to compare the influences of each conductance component on VO2 MAX at three altitudes: PB = 760, 464 and 253 Torr. For any given set of conductances the analysis simultaneously solved six equations for alveolar, arterial, and venous PO2 and PcO2. The equations represent pulmonary mass balance, pulmonary diffusion, and muscle diffusion for both gases. At PB = 760, [Hb], DLO2 and DMO2 were as influential as QT in limiting VO2 MAX. With increasing altitude, the influence of QT and [Hb] fell while that of VA, DLO2 and DMO2 progressively increased until at PB = 253, VO2 MAX was independent of QT and [Hb]. Neither the fall in maximal QT nor rise in [Hb] with chronic hypoxia therefore appear to affect VO2 MAX. However, high values of ventilation, DLO2 and DMO2 appear to be advantageous for exercise at altitude.

  11. VO2 max is associated with ACE genotype in postmenopausal women.

    Science.gov (United States)

    Hagberg, J M; Ferrell, R E; McCole, S D; Wilund, K R; Moore, G E

    1998-11-01

    Relationships have frequently been found between angiotensin-converting enzyme (ACE) genotype and various pathological and physiological cardiovascular outcomes and functions. Thus we sought to determine whether ACE genotype affected maximal O2 consumption (VO2 max) and maximal exercise hemodynamics in postmenopausal women with different habitual physical activity levels. Age, body composition, and habitual physical activity levels did not differ among ACE genotype groups. However, ACE insertion/insertion (II) genotype carriers had a 6.3 ml . kg-1 . min-1 higher VO2 max (P VO2 max (P VO2 max than the DD genotype group, but the difference was not significant. ACE genotype accounted for 12% of the variation in VO2 max among women after accounting for the effect of habitual physical activity levels. The entire difference in VO2 max among ACE genotype groups was the result of differences in maximal arteriovenous O2 difference (a-vDO2). ACE genotype accounted for 17% of the variation in maximal a-vDO2 in these women. Maximal cardiac output index did not differ whatsoever among ACE genotype groups. Thus it appears that ACE genotype accounts for a significant portion of the interindividual differences in VO2 max among these women. However, this difference is the result of genotype-dependent differences in maximal a-vDO2 and not of maximal stroke volume and maximal cardiac output.

  12. Is time limit at the minimum swimming velocity of VO2 max influenced by stroking parameters?

    Science.gov (United States)

    Fernandes, Ricardo J; Marinho, Daniel A; Barbosa, Tiago M; Vilas-Boas, J Paulo

    2006-08-01

    The aim of this study was to observe the relationship between time limit at the minimum velocity that elicits maximal oxygen consumption (TLim-v VO2 max) and stroke rate, stroke length, and stroke index. 13 men and 10 women, highly trained swimmers, performed an intermittent incremental test for v VO2 max assessment and an all-out swim to estimate TLim-v VO2 max. The mean +/- SD TLim-v VO2 max, v VO2 max, stroke rate, stroke length, and stroke index values were 233.36 +/- 53.92 sec., 1.40 +/- .06 meter/sec., 35.58 +/- 2.89 cycles/min., 2.39 +/- .22 meter/cycle, and 3.36 +/- .41 meter2/(cycle x sec.), respectively. The correlation between TLim-v VO2 max and stroke rate was -.51 (p VO2 max with stroke length (r = .52, p < .01) and stroke index (r = .45, p < .05). These results seem to suggest that technical skill is a key factor in typical efforts requiring prolonged aerobic power.

  13. Structure and stability of monazite- and zircon-type LaVO4 under hydrostatic pressure

    Science.gov (United States)

    Cheng, Xuerui; Guo, Dongjie; Feng, Shiquan; Yang, Kun; Wang, Yongqiang; Ren, Yufen; Song, Yang

    2015-11-01

    Pure monazite (m)- and zircon (t)-type LaVO4 and LaVO4:Eu3+ were successfully synthesized by a hydrothermal method. The high pressure behavior of m- and t-LaVO4 nanoparticles has been investigated using Raman scattering techniques at room temperature. Raman measurements reveal a slight change for m-LaVO4 at 11.2 GPa because of an isostructural phase transition. However, striking changes in Raman spectra indicate a pressure-induced irreversible phase transition from the zircon to monazite structure for t-LaVO4 at around 5.9 GPa. The evolution of the luminescence spectra of t-LaVO4:Eu3+ has also been studied during the pressure-induced phase transition. It is observed that pressure has a great influence on the fluorescence intensity and the energy levels, which allows a more in-depth understanding of the nature of the pressure-induced phase transition for t-LaVO4. This result further confirms the conclusion that zircon-type RVO4 compounds with larger rare-earth cations will experience zircon to monazite phase transition.

  14. The influence of VO2(B nanobelts on thermal decomposition of ammonium perchlorate

    Directory of Open Access Journals (Sweden)

    Zhang Yifu

    2015-09-01

    Full Text Available The influence of vanadium dioxide VO2(B on thermal decomposition of ammonium perchlorate (AP has not been reported before. In this contribution, the effect of VO2(B nanobelts on the thermal decomposition of AP was investigated by the Thermo- Gravimetric Analysis and Differential Thermal Analysis (TG/DTA. VO2(B nanobelts were hydrothermally prepared using peroxovanadium (V complexes, ethanol and water as starting materials. The thermal decomposition temperatures of AP in the presence of I wt.%, 3 wt.% and 6 wt.% of as-obtained VO2VO2(B nanobelts had a great influence on the thermal decomposition temperature of AP Furthermore, the influence of the corresponding V2Os, which was obtained by thermal treatment of VO2(B nanobelts, on the thermal decomposition of AP was also investigated. The resufs showed that VO2(B nanobelts had a greater influence on the thermal decomposition temperature of AP than that of V2Os.

  15. BiVO{sub 4}-graphene catalyst and its high photocatalytic performance under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fu Yongsheng [Key Laboratory of Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Key Laboratory of Fine Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Sun Xiaoqiang, E-mail: xqsun@cczu.edu.cn [Key Laboratory of Fine Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Wang Xin, E-mail: wxin@public1.ptt.js.cn [Key Laboratory of Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Ministry of Education, Nanjing 210094 (China); Key Laboratory of Jiangsu Province for Chemical Pollution Control and Resources Reuse, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer A facile strategy is designed to deposit leaf-like BiVO{sub 4} lamellas on graphene sheet. Black-Right-Pointing-Pointer Graphene oxide is reduced to graphene in the hydrothermal reaction process. Black-Right-Pointing-Pointer BiVO{sub 4}-graphene system shows high catalytic effects under visible light irradiation. - Abstract: A BiVO{sub 4}-graphene photocatalyst was prepared by a facile one-step hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM) techniques. The results show that the graphene sheets in this catalyst are exfoliated and decorated by leaf-like BiVO{sub 4} lamellas. In comparison with the pure BiVO{sub 4} catalyst, the BiVO{sub 4}-graphene system reveals much higher photocatalytic activity for degradation of methyl orange (MO), methylene blue (MB), Rhodamine B (RhB) and active black BL-G in water under visible light irradiation due to the concerted effects of BiVO{sub 4} and graphene sheets or their integrated properties.

  16. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos Influencia del Estado Nutricional y del VO2max en los Niveles de Adiponectina en Hombres que superan los 35 Años Influence of nutritional status and VO2max on adiponectin levels in men older than 35 years

    Directory of Open Access Journals (Sweden)

    Eduardo Camillo Martinez

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condicionamento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adultos. MÉTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exército Brasileiro (42,6 ± 4,8 anos. Foram mensurados os níveis plasmáticos de adiponectina, massa corporal, estatura, circunferência da cintura (CC, percentual de gordura por pesagem hidrostática e VO2max por ergoespirometria. Um questionário foi utilizado para obter as características do treinamento físico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48% sujeitos apresentaram sobrepeso e 36 (14% eram obesos. Ainda, 66 sujeitos (27% apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relação aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram níveis de adiponectina mais altos que os demais. Os níveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento físico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlação dos níveis de adiponectina e do VO2max não permaneceu significante após controlada pelo IMC e CC. CONCLUSÃO: Sujeitos com melhor condicionamento cardiorrespiratório e com estado nutricional normal parecem apresentar níveis mais saudáveis de adiponectina.FUNDAMENTO: La adiponectina es considerada un importante factor en la patogénesis de las enfermedades

  17. BiVO4 photoanodes for water splitting with high injection efficiency, deposited by reactive magnetron co-sputtering

    OpenAIRE

    Haibo Gong; Norman Freudenberg; Man Nie; Roel van de Krol; Klaus Ellmer

    2016-01-01

    Photoactive bismuth vanadate (BiVO4) thin films were deposited by reactive co-magnetron sputtering from metallic Bi and V targets. The effects of the V-to-Bi ratio, molybdenum doping and post-annealing on the crystallographic and photoelectrochemical (PEC) properties of the BiVO4 films were investigated. Phase-pure monoclinic BiVO4 films, which are more photoactive than the tetragonal BiVO4 phase, were obtained under slightly vanadium-rich conditions. After annealing of the Mo-doped BiVO4 fil...

  18. REDUCCIÓN DE LA BIOMASA DEL PINO CARRASCO (PINUS HALEPENSIS EN UN ÁREA DEL SURESTE SEMIÁRIDO PENINSULAR COMO ESTRATEGIA PARA EVITAR EL ESTRÉS HÍDRICO

    Directory of Open Access Journals (Sweden)

    Francisco Belmonte Serrato

    2008-01-01

    Full Text Available En las épocas de fuertes sequías, la vegetación mediterránea sufre un estado de estrés hídrico prolongado que le obliga a adoptar diversas estrategias de supervivencia, entre las que fi guran, como último recurso, y antes de llegar a superar su capacidad de resilencia, la reducción de la biomasa de hojas. En este trabajo se pone de manifi esto como algunos ejemplares de Pinus halepensis existentes en el área de estudio (el campo experimental de El Ardal, Murcia, redujeron apreciablemente su biomasa aérea en respuesta a la sequía, que se manifestó en un importante aumento de la producción de hojarasca. La producción de hojarasca se relaciona además de con la precipitación registrada en el periodo de estudio, con la humedad del suelo, parámetro clave en la supervivencia de la vegetación en ambientes secos.

  19. Expression of VO2peak in Children and Youth, with Special Reference to Allometric Scaling.

    Science.gov (United States)

    Loftin, Mark; Sothern, Melinda; Abe, Takashi; Bonis, Marc

    2016-10-01

    The aim of this review was to highlight research that has focused on examining expressions of peak oxygen uptake (VO2peak) in children and youth, with special reference to allometric scaling. VO2peak is considered the highest VO2 during an increasing workload treadmill or bicycle ergometer test until volitional termination. We have reviewed scholarly works identified from PubMed, One Search, EBSCOhost and Google Scholar that examined VO2peak in absolute units (L·min(-1)), relative units [body mass, fat-free mass (FFM)], and allometric expressions [mass, height, lean body mass (LBM) or LBM of the legs raised to a power function] through July 2015. Often, the objective of measuring VO2peak is to evaluate cardiorespiratory function and fitness level. Since body size (body mass and height) frequently vary greatly in children and youth, expressing VO2peak in dimensionless units is often inappropriate for comparative or explanatory purposes. Consequently, expressing VO2peak in allometric units has gained increased research attention over the past 2 decades. In our review, scaling mass was the most frequent variable employed, with coefficients ranging from approximately 0.30 to over 1.0. The wide variance is probably due to several factors, including mass, height, LBM, sex, age, physical training, and small sample size. In summary, we recommend that since skeletal muscle is paramount for human locomotion, an allometric expression of VO2peak relative to LBM is the best expression of VO2peak in children and youth.

  20. Effects of high-intensity interval training on the VO2 response during severe exercise.

    Science.gov (United States)

    Duffield, Rob; Edge, Johann; Bishop, David

    2006-06-01

    This study examined the effect of high-intensity interval training on the VO2 response during severe, constant-load exercise. Prior to, and following training, 10 females (V O2 peak 37.4+/-6.0 mL kg-1 min-1) performed a graded exercise test to determine VO2 peak and lactate threshold (LT) and a 6 min cycle test (CT) at the pre-training VO2 peak intensity. Training involved high-intensity intervals (2 min work, 1 min rest) performed 3x week for 8 weeks. Breath-by-breath data from 0 to 6 min during the CT were smoothed using 5s averages and fit to a bi-exponential model starting from 20s. Training resulted in significant improvements in VO2 max (2.34+/-0.37-2.78+/-0.30 L min-1), power at VO2 max (170+/-26-204+/-25 W) and power at LT (113+/-17-136+/-20 W) (pVO2 response showed a significant increase in the amplitude of the primary phase (A1) (1396+/-103-1695+/-100 mL min-1; pVO2 (VO2 EE), with no difference (p>0.05) in the time constants of either phase or the amplitude of the slow component (318+/-67-380+/-48 mL; p=0.15). In conjunction, accumulated oxygen deficit (AOD) (43.7+/-9.8-17.2+/-2.8 mL O2 eq kg-1) and anaerobic contribution to the CT (19.4+/-4.4-7.2+/-1.2%) were significantly reduced. In contrast to previous moderate-intensity research, a high-intensity interval training program increased A1 and VO2 EE for the same absolute exercise intensity, decreasing the AOD during a severe-intensity CT.

  1. VO(2) based waveguide-mode plasmonic nano-gratings for optical switching.

    Science.gov (United States)

    Sharma, Yashna; Tiruveedhula, Veeranjaneya A; Muth, John F; Dhawan, Anuj

    2015-03-09

    In this paper, we present one dimensional plasmonic narrow groove nano-gratings, covered with a thin film of VO(2) (Vanadium Dioxide), as novel optical switches. These narrow groove gratings couple the incident optical radiation to plasmonic waveguide modes leading to high electromagnetic fields in the gaps between the nano-gratings. Since VO(2) changes from its semiconductor to its metallic phase on heating, on exposure to infra-red light, or on application of voltage, the optical properties of the underlying plasmonic grating also get altered during this phase transition, thereby resulting in significant switchability of the reflectance spectra. Moreover, as the phase transition in VO(2) can occur at femto-second time-scales, the VO(2)-coated plasmonic optical switch described in this paper can potentially be employed for ultrafast optical switching. We aim at maximizing this switchability, i.e., maximizing the differential reflectance (DR) between the two states (metallic and semiconductor) of this VO(2) coated nano-grating. Rigorous Coupled Wave Analysis (RCWA) reveals that the switching wavelengths - i.e., the wavelengths at which the values of the differential reflectance between VO(2) (S) and VO(2) (M) phases are maximum - can be tuned over a large spectral regime by varying the nano-grating parameters such as groove width, depth of the narrow groove, grating width, and thickness of the VO(2) layer. A comparison of the proposed ideal nano-gratings with various types of non-ideal nano-gratings - i.e., nano-gratings with non-parallel sidewalls - has also been carried out. It is found that significant switchability is also present for these non-ideal gratings that are easy to fabricate. Thus, we propose highly switchable and wide-spectra VO(2) based narrow groove nano-gratings that do not have a complex structure and can be easily fabricated.

  2. Energy star compliant voice over internet protocol (VoIP) telecommunications network including energy star compliant VoIP devices

    Energy Technology Data Exchange (ETDEWEB)

    Kouchri, Farrokh Mohammadzadeh

    2012-11-06

    A Voice over Internet Protocol (VoIP) communications system, a method of managing a communications network in such a system and a program product therefore. The system/network includes an ENERGY STAR (E-star) aware softswitch and E-star compliant communications devices at system endpoints. The E-star aware softswitch allows E-star compliant communications devices to enter and remain in power saving mode. The E-star aware softswitch spools messages and forwards only selected messages (e.g., calls) to the devices in power saving mode. When the E-star compliant communications devices exit power saving mode, the E-star aware softswitch forwards spooled messages.

  3. TRANSPORTE DE VOZ (VoIP SOBRE REDES IPv4 e IPv6

    Directory of Open Access Journals (Sweden)

    Fausto Alexander Gamboa

    2012-05-01

    Full Text Available El presente artículo tiene como finalidad evaluar el comportamiento de la VoIP en redes IPv6 y compararlo con IPv4, de igual manera presentar las arquitecturas que la soportan. Con el fin de que los resultados sean los más cercanos a la realidad, el artículo no solo se soporta en simulaciones si no en implementaciones reales. Dentro de las conclusiones más sobresalientes se encontró que la VoIP6 presenta mejor rendimiento ante el Jitter y el retardo que VoIPv4.

  4. Bismuth zinc vanadate, BiZn2VO6 : new crystal structure type and electronic structure.

    OpenAIRE

    Nunes, Sayonara Eliziario; Wang, Chun-Hai; So, Karwei; Evans, John S. O.; Evans, Ivana Radosavljevic

    2015-01-01

    We report a combined experimental and computational study of the crystal structure and electronic properties of bismuth zinc vanadate, BiZn2VO6, known for its visible light photocatalytic activity. The crystal structure has been solved from laboratory powder X-ray diffraction data using the repeated minimisations from random starting values method. BiZn2VO6 adopts a new structure type, based on the following building blocks: corner- and edge-sharing ZnO4 tetrahedra, ZnO6 octahedra and VO4 tet...

  5. Theoretical investigation of the optical and EPR parameters for VO 2+ion in some complexes

    Science.gov (United States)

    Kalfaoğlu, Emel; Karabulut, Bünyamin

    2012-04-01

    The molecular orbital coefficients and the EPR parameters of trisodium citrate dihydrate, sodium hydrogen oxalate monohydrate, potassium d-gluconate monohydrate and L-Alanine vanadyl complexes are calculated theoretically. Two d-d transition spectra and EPR parameters for the VO2+ complex are calculated theoretically by using crystal-field theory. The calculated g and A paramaters have indicated that paramagnetic center is axially symmetric. Having the relations of g∥A⊥ for VO2+ ions, it can be concluded that VO2+ ions are located in distorted octahedral sites (C4v) elongated along the z-axis and the ground state of the paramagnetic electron is dxy.

  6. Inhomogeneous electronic state near the insulator-to-metal transition in the correlated oxide VO2

    Science.gov (United States)

    Frenzel, A.; Qazilbash, M. M.; Brehm, M.; Chae, Byung-Gyu; Kim, Bong-Jun; Kim, Hyun-Tak; Balatsky, A. V.; Keilmann, F.; Basov, D. N.

    2009-09-01

    We investigate the percolative insulator-to-metal transition (IMT) in films of the correlated material vanadium dioxide (VO2) . Scattering-type scanning near-field infrared microscopy and atomic force microscopy were used to explore the relationship between the nucleation of metallic regions and the topography in insulating VO2 . We demonstrate that the IMT begins within 10 nm from grain boundaries and crevices by using mean curvature and statistical analysis. We also observe coexistence of insulating and metallic domains in a single crystalline grain that points to intrinsic inhomogeneity in VO2 due to competing electronic phases in the IMT regime.

  7. Dynamic Control of Light Emission Faster than the Lifetime Limit Using VO2 Phase-Change

    Science.gov (United States)

    2015-10-22

    stack is constructed in this way, there is a p phase shift in the effective optical path length when the VO2 is switched from the insulating to metallic...nm. For this particular geometry, the device is designed such that the emitter layer has a high magnetic LDOS when VO2 is in the insulating state, but...emitter. We leverage the ultrafast insulator -to-metal transition (IMT) of vanadium dioxide (VO2)2–4 as well as the symmetry difference in the

  8. ST-ECF Archive: a SIAP service in the path towards the VO

    Science.gov (United States)

    Sforna, D.; Micol, A.; Albrecht, R.

    2006-07-01

    In the following, we describe the current status of the ST-ECF Archive (the European HST Science Archive) and our roadmap to make it technically VO compliant and scientifically better characterised. The on-going plans for the Hubble Legacy Archive will be also mentioned. The roadmap includes a change of paradigm from products built on-the-fly upon request to the generation of a cache of products ready for exploitation. As a first step in offering cached products, we present a VO SIAP service for the HST preview images. Simple Image Access Protocol. For references on all VO standards see http://www.ivoa.net/Documents/latest/.

  9. Influence of prior exercise on VO2 kinetics subsequent exhaustive rowing performance.

    Science.gov (United States)

    Sousa, Ana; Ribeiro, João; Sousa, Marisa; Vilas-Boas, João Paulo; Fernandes, Ricardo J

    2014-01-01

    Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercise time during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderate exercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longer exercise time at VO2max. Six subjects (mean ± SD; age: 22.9±4.5 yr; height: 181.2±7.1 cm and body mass: 75.5±3.4 kg) completed square-wave transitions to 100% of VO2max from three different conditions: without prior exercise, with prior moderate and heavy exercise. VO2 was measured using a telemetric portable gas analyser (K4b(2), Cosmed, Rome, Italy) and the data were modelled using either mono or double exponential fittings. The use of prior moderate exercise resulted in a faster VO2 pulmonary kinetics response (τ1 = 13.41±3.96 s), an improved performance in the time to exhaustion (238.8±50.2 s) and similar blood lactate concentrations ([La(-)]) values (11.8±1.7 mmol.L(-1)) compared to the condition without prior exercise (16.0±5.56 s, 215.3±60.1 s and 10.7±1.2 mmol.L(-1), for τ1, time sustained at VO2max and [La(-)], respectively). Performance of prior heavy exercise, although useful in accelerating the VO2 pulmonary kinetics response during a subsequent time to exhaustion exercise (τ1 = 9.18±1.60 s), resulted in a shorter time sustained at VO2max (155.5±46.0 s), while [La(-)] was similar (13.5±1.7 mmol.L(-1)) compared to the other two conditions. Although both prior moderate and heavy exercise resulted in a faster pulmonary VO2 kinetics response, only prior moderate exercise lead to improved rowing performance.

  10. Research and Realization of the VoIP Traversing NAT Used by SBC%SBC助VoIP穿越NAT的设计与实现

    Institute of Scientific and Technical Information of China (English)

    陈惠红; 曾志文; 刘世明

    2008-01-01

    随着技术的成熟,VoIP技术以更加迅猛的势头得到发展和普及,但是在这个过程中也不可避免的碰到一些困难和问题,VoIP应用如何穿越NAT的问题就是其中之一.本文研究了NAT技术给VoIP服务带来的问题,并且就当前最佳的NAT穿透方案SBC进行探讨,然后在此基础上选择一个无须对现有设备进行任何改动SBC穿越NAT方案--Pinhole.研究SBC-Pinhole在典型的网络VoIP构架系统中的设计.SBC方案,是迄今为止,对FW/NAT问题解决最完善的方案,实施SBC针孔解决方案,可以协助VoIP信令与媒体流穿越穿越远端防火墙/NAT设备.所有经过SBC的信令和媒体流可以在系统侧和用户侧正确传输,而不需要对现有的FW/NAT设备做任何改变..

  11. Analisis Unjuk Kerja Aplikasi VoIP Call Android di Jaringan MANET [Performance Analysis of VoIP Call Application Android in MANET (Mobile Ad Hoc Network

    Directory of Open Access Journals (Sweden)

    Ryan Ari Setyawan

    2015-06-01

    Full Text Available Penelitian ini bertujuan menganalisis kinerja aplikasi  VoIP call android di jaringan MANET (mobile ad hoc network.  Hasil pengujian menunjukan bahwa aplikasi VoIP call android dapat digunakan di jaringan MANET. Delay yang dihasilkan paling besar di pengujian indoor dengan jarak 11-15 meter yakni sebesar 0,014624811 seconds. Packet loss yang dihasilkan pada range 1%-2% sedangkan standar packet loss yang ditetapkan oleh CISCO untuk layanan aplikasi VoIP adalah < 5%. Jitter yang dihasilkan yakni antara 0,01-0,06 seconds sedangkan standar yang ditetapkan oleh CISCO adalah ≤ 30 ms atau 0,03 seconds. Throughput yang dihasilkan pada proses pengujian yakni antar 161 kbps-481 kbps. *****This study aims to analyze the performance of VOIP call android application in the MANET (mobile ad hoc network. The results showed that VoIP applications could be implemented in MANET network. The highest  delay is produced in indoor testing  with distance of 11-15 meters,  which is equal to 0.014624811 seconds. Packet loss is generated in the range of 1% -2%, while packet loss standards set by Cisco for VoIP application services are <5%. The jitter is between 0.01 to 0.06 seconds, while the standard set by CISCO is ≤ 30 ms or 0.03 seconds. Throughput generated in the testing process is between 161 kbps-481 kbps.

  12. Elastic, electronic and magnetic properties of new oxide perovskite BaVO{sub 3}: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Bannikov, V.V., E-mail: bannikov@ihim.uran.ru

    2016-03-01

    The structural, elastic, magnetic properties, as well as electronic structure and chemical bonding picture of new oxide 3d{sup 1}-perovskite BaVO{sub 3}, recently synthesized, were systematically investigated involving the first-principles FLAPW-GGA calculations. The obtained results are discussed in comparison with available experimental data, as well as with those obtained before for isostructural and isoelectronic SrVO{sub 3} perovskite. - Highlights: • BaVO{sub 3} is more compressible, but stiffer with respect to shear than SrVO{sub 3}. • Maximal Young's modulus for BaVO{sub 3} is ∼303 GPa - in [111] direction. • BaVO{sub 3} is characterized with negative Cauchy pressure. • BaVO{sub 3} is so-called “exchange-enhanced” Pauli paramagnet.

  13. Comportamiento de la biomasa y de las tasas de crecimiento de dos variedades de lulo (Solanum quitoense Lam. en Pachavita, Boyacá

    Directory of Open Access Journals (Sweden)

    Pedro José Almanza-Merchán

    2016-01-01

    Full Text Available Se estudió la dinámica del crecimiento y desarrollo del fruto de dos variedades de lulo (chonto grueso y criollo bajo las condiciones del municipio de Pachavita (Boyacá. Se evaluaron la biomasa seca y las tasas de Crecimiento Absoluto (TAC y de Crecimiento Relativa (TRC. Los frutos de las dos variedades presentaron crecimiento tipo sigmoide simple, con tres fases que se describieron como: FI (división celular, FII (elongación celular y FIII (maduración. La variedad Chonto grueso mostró un incremento exponencial en la TAC, que abarcó la FI y parte de la FII, hasta los 78 días después de antesis (dda, cuando alcanzó su mayor valor, de 0,117 g/día, y una rápida ganancia de masa seca hasta este punto; luego disminuyó hasta la cosecha. La variedad Criollo mostró un aumento lento en la FI, que fue progresivo hasta llegar a su máximo valor a los 128 dda, acumulando 0,107 g/día, lo que implicó un aumento de tamaño más lento en el tiempo; demostrando mayor poder vertedero inicial en la variedad Chonto grueso, respecto a la variedad Criollo, en términos de materia seca. La TRC para la variedad Chonto grueso mostró una lenta disminución en la FI, reduciéndose drásticamente en la FII y lentamente en la FIII; en tanto que la variedad Criollo mostró un descenso gradual y constante hasta los 140 dda. Se estableció, para la variedad Chonto grueso en la FIII, y en general para la variedad Criollo, una baja tasa de variación del tamaño por unidad de tamaño inicial.

  14. Reproducibility of maximum aerobic power (VO2max among soccer players using a modified heck protocol Reprodutibilidade da potência aeróbia máxima (VO2max em jogadores de futebol utilizando o protocolo de heck modificado

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos-Silva

    2007-01-01

    Full Text Available OBJECTIVE: To determine the degree of reproducibility of maximum oxygen consumption (VO2max among soccer players, using a modified Heck protocol. METHODS: 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance level; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3% during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. RESULTS: The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 ± 1.1 vs. 15.7 ± 1.2 km.h-1; [P = .78] and (54.5 ± 3.9 vs. 55.2 ± 4.4 ml.kg-1.min-1; [P = .88]. There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P OBJETIVO: Determinar o grau de reprodutibilidade do consumo máximo de oxigênio (VO2max em jogadores de futebol utilizando o protocolo de Heck modificado. MÉTODOS: Foram avaliados por duas vezes, com intervalo de 15 dias entre os testes, 11 futebolistas masculinos. Todos eram de alto nível, treinavam em média 10 horas por semana subdivididos em treinamentos físicos, técnicos, táticos e jogos competitivos, totalizando cinco vezes por semana e na fase em que foram avaliados se encontravam em pleno período competitivo realizando um jogo por semana. Os futebolistas foram avaliados em esteira ergométrica (1,2 km.h-1 a cada dois minutos e inclinação fixa durante o teste em 3%. O VO2max foi medido diretamente utilizando analisador metabólico de análise de gases expirados respiração-a-respiração. RESULTADOS: A velocidade máxima de corrida e o VO2max atingido nos dois testes foram respectivamente: (15,6 ± 1

  15. Systems Analysis of the VoIP Based on P2P Overlay%基于P2P重叠网的VoIP系统实现

    Institute of Scientific and Technical Information of China (English)

    廖小成; 龙昭华; 杨令

    2007-01-01

    随着网络技术的日益发展和普及,VoIP(Voice Over Internet Protocol)应用增长迅速,出现了很多新的应用技术,其中最具有代表性的是P2P(Peer to Peer)重叠网的应用;能够将VoIP技术与P2P结合无疑是一种新的有价值的尝试.文中在分析了现有P2P通信机制的基础上,选用Chord协议并结合SIP协议实现一种基于P2P模式的VoIP系统.

  16. Chapter 29: Using an Existing Environment in the VO (IDL)

    Science.gov (United States)

    Miller, C. J.

    The local environment of a Brightest Cluster Galaxy (BCG) can provide insight into the (still not understood) formation process of the BCG itself. BCGs are the most massive galaxies in the Universe, and their formation and evolution are a popular and current research topic (Linden et al. 2006, Bernardi et al. 2006, Lauer et al. 2006). They have been studied for some time (Sandage 1972, Ostriker & Tremaine 1975, White 1976, Thuan & Romanishin 1981, Merritt 1985, Postman and Lauer 1995, among many others). Our goal in this chapter is to study how the local environment can affect the physical and measurable properties of BCGs. We will conduct an exploratory research exercise. In this chapter, we will show how the Virtual Observatory (VO) can be effectively utilized for doing modern scientific research on BCGs. We identify the scientific functionalities we need, the datasets we require, and the service locations in order to discover and access those data. This chapter utilizes IDL's VOlib, which is described in Chapter 24 of this book and is available at http://www.nvo.noao.edu. IDL provides the capability to perform the entire range of astronomical scientific analyses in one environment: from image reduction and analysis to complex catalog manipulations, statistics, and publication quality figures. At the 2005 and 2006 NVO Summer Schools, user statistics show that IDL was the most commonly used programming language by the students (nearly 3-to-1 over languages like IRAF, Perl, and Python). In this chapter we show how the integration of IDL to the VO through VOlib provides even greater capabilities and possibilities for conducting science in the era of the Virtual Observatory. The reader should familiarize themselves with the VOlib libraries before attempting the examples in this tutorial. We first build a research plan. We then discover the service URLs we will need to access the data. We then apply the necessary functions and tools to these data before we can do our

  17. Effect of variety and cane yield on sugarcane potential trash Efecto de las variedades y su rendimiento cultural en la biomasa residual potencial

    Directory of Open Access Journals (Sweden)

    Eduardo R. Romero

    , conservando el suelo y ofreciendo una posibilidad para la generación de energía. Una estimación del potencial de residuos disponible de la caña de azúcar cobra gran relevancia en el momento de definir estrategias de manejo. Se realizó un estudio para determinar la cantidad de biomasa residual disponible en los cañaverales en forma previa (SPT y posterior (SFT a la cosecha mecanizada en verde para las principales variedades cultivadas en la provincia de Tucumán (LCP 85-384, TUCCP 77-42, CP 65-357 y RA 87-3. Además, se estudió la relación entre SPT y SFT a fin de validar la precisión de SPT como predictor de SFT en el caso de la cosecha integral en verde. El incremento del SPT estuvo asociado al mayor rendimiento cultural/ha, registrándose valores del 6,9 a 16,0 t/ha de biomasa residual para rendimientos culturales de 32 a 104 t/ha. LCP 85-384 y CP 65-357 produjeron el mayor SPT, mientras que TUCCP 77-42 generó la menor cantidad para niveles similares de rendimiento cultural. La relación SPT/CY disminuyó y el promedio general fue del 16% del rendimiento cultural, aunque su uso para estimar SPT fue limitado, como señalan los bajos coeficientes de determinación. SPT predijo adecuadamente SFT para el caso de la cosecha integral en verde, y el primero puede ser estimado adecuadamente empleando el rendimiento cultural/ha.

  18. Efecto de la sequía en la producción de biomasa y grano de frijol Drought effect in bean biomass and grain production

    Directory of Open Access Journals (Sweden)

    Efraín Acosta-Díaz

    2011-04-01

    Full Text Available La sequía intermitente es el factor que más limita la producción de frijol (Phaseolus vulgaris L. bajo temporal en México. El objetivo fue determinar el efecto de la sequía sobre la acumulación de biomasa del vástago y el rendimiento de grano en variedades criollas e introducidas de frijol de temporal. Se establecieron dos experimentos, uno con 21 variedades nativas y otro con 15 variedades introducidas, de diferente hábito de crecimiento indeterminado, en la Unidad Académica La Ascensión de la Facultad de Agronomía de la Universidad Autónoma de Nuevo León, México en 2009. Los experimentos se condujeron bajo dos tratamientos de humedad del suelo: riego durante todo el ciclo y sequía. En el tratamiento de riego el suelo se mantuvo por encima de 60% de humedad aprovechable durante el ciclo del cultivo, mediante la precipitación y cuatro riegos de auxilio (dos antes y otros dos después de floración, mientras que en el tratamiento de sequía el riego se suspendió a partir del inicio de la floración. En los dos experimentos, bajo la condición de sequía la acumulación de biomasa del vástago y el rendimiento de grano fue significativamente inferior (p≤ 0.01 que en el tratamiento de riego. En general, el efecto del tratamiento de sequía sobre el peso seco del vástago fue mayor en las variedades nativas, mientras que el efecto sobre el rendimiento de grano fue mayor en las variedades introducidas. En sequía, las variedades de mayor rendimiento, fueron: nativas, Pinto-2, Pinto-1, Amarillo Mantequilla, Boleado, Bayo Blanco, Canelo y Quipincillo Rojo-1 e introducidas, Peruano, Flor de Mayo Media Oreja, Pinto-5 y Ojo de Cabra. De acuerdo con el índice de susceptibilidad a la sequía y la media geométrica, las variedades más eficientes para la producción de rendimiento de grano en ambas condiciones de humedad fueron: Pinto-2, Amarillo Mantequilla, Pinto-1, Boleado, Peruano, Flor de Mayo Media Oreja, Pinto-5 y Ojo de Cabra; sin

  19. Control of room-temperature defect-mediated ferromagnetism in VO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tsung-Han, E-mail: tyang3@ncsu.edu [NSF Center for Advanced Materials and Smart Structures, Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907 (United States); Nori, Sudhakar; Mal, Siddhartha; Narayan, Jagdish [NSF Center for Advanced Materials and Smart Structures, Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907 (United States)

    2011-09-15

    We report interesting ferromagnetic properties and their control in a vanadium-based oxide system driven by stoichiometric defects. Vanadium oxide (VO{sub 2}) thin films were grown on c-plane sapphire substrates by a pulsed laser deposition technique under different ambient conditions. The ferromagnetism of the epitaxial VO{sub 2} films can be switched on and off by altering the cooling ambient parameters. In addition, the saturated magnetic moments and coercivity of the VO{sub 2} films were found to be a function of the oxygen partial pressure during the growth process. The room-temperature ferromagnetic properties of VO{sub 2} films were correlated with the nature of the microstructure and the growth parameters. The origin of the induced magnetic properties are qualitatively understood to stem from intrinsic structural and stoichiometric defects.

  20. EVALUATION AND DEVELOPMENT OF THE VO2 OF ATHLETES THAT ATTEND A SOCCER SCHOOL

    Directory of Open Access Journals (Sweden)

    Felipe Bittencourt Oliveira

    2012-11-01

    Full Text Available The goal of this study was to identify the effects from technical and physical activities on the VO2, of male athletes aged 14 to 15, participants of a soccer school, in the municipality of Rio Pardo - RS. The semi-experimental research involved 10 male adolescents. For the VO2 evaluation the 12 minute Cooper test was used. Interval-training work was applied, at which the athletes exercised 75% of their maximum speed, in 60-meter runs. After training for two months (at least two sessions a week the Cooper post-test was applied to check the improvement of the VO2. As results of this study, we can draw the conclusion that all adolescents involved in this training showed considerable improvement in their maximum VO2, especially the 15-year-old teens, who managed to obtain a much higher percentage level.

  1. Photocatalytic C−H Activation of Hydrocarbons over VO@g‑C3N4

    Data.gov (United States)

    U.S. Environmental Protection Agency — A highly selective and sustainable method has been developed for the oxidation of methyl arenes and their analogues. The VO@g-C3N4 catalyst is very efficient in the...

  2. High performance of solvothermally prepared VO2(B as anode for aqueous rechargeable lithium batteries

    Directory of Open Access Journals (Sweden)

    Milošević Sanja

    2015-01-01

    Full Text Available The VO2 (B was synthesized via a simple solvothermal route at 160oC in ethanol. The initial discharge capacity of VO2 (B anode, in saturated aqueous solution of LiNO3, was 177 mAh g-1 at a current rate of 50 mA g-1. After 50 cycles capacity fade was 4%, but from 20th-50th cycle no capacity drop was observed. The VO2 (B has shown very good cyclability at current rate of even 1000 mA g-1 with initial discharge capacity of 92 mAh g-1. The excellent electrochemical performance of VO2 (B was attributed to the stability of micro-nano structures to repeated intercalation /deintercalation process, very good electronic conductivity as well as the very low charge transfer resistance in the aqueous electrolyte. [Projekat Ministarstva nauke Republike Srbije, br. III45014

  3. Comparison of intensities and rest periods for VO2max verification testing procedures.

    Science.gov (United States)

    Nolan, P B; Beaven, M L; Dalleck, L

    2014-11-01

    We sought to determine the incidence of 'true' VO2max confirmation with the verification procedure across different protocols. 12 active participants (men n=6, women n=6) performed in random order 4 different maximal graded exercises tests (GXT) and verification bout protocols on 4 separate days. Conditions for the rest period and verification bout intensity were: A - 105% intensity, 20 min rest; B - 105% intensity, 60 min rest; C - 115% intensity, 20 min rest; D - 115% intensity, 60 min rest. VO2max confirmation (difference between peak VO2 GXT and verification trialrest periods. We recommend the use of 105% of the maximal GXT workload and 20 min rest periods when using verification trials to confirm VO2max in normally active populations.

  4. VoIP for Telerehabilitation: A Pilot Usability Study for HIPAA Compliance

    Directory of Open Access Journals (Sweden)

    Valerie R. Watzlaf

    2012-06-01

    Full Text Available Consumer-based, free Voice and video over the Internet Protocol (VoIP software systems such as Skype and others are used by health care providers to deliver telerehabilitation and other health-related services to clients. Privacy and security applications as well as HIPAA compliance within these protocols have been questioned by practitioners, health information managers, and other healthcare entities. This pilot usability study examined whether four respondents who used the top three, free consumer-based, VoIP software systems perceived these VoIP technologies to be private, secure, and HIPAA compliant;  most did not.  While the pilot study limitations include the number of respondents and systems assessed, the protocol can be applied to future research and replicated for instructional purposes.  Recommendations are provided for VoIP companies, providers, and users. 

  5. 使VoIP用户体验超越QoS

    Institute of Scientific and Technical Information of China (English)

    Tom Flanagan; Debbie Greenstreet

    2006-01-01

    目前,大多数传统网络服务供应商才刚开始推出VoIP服务。在早期阶段,众多供应商仅提供简单的VoIP通信功能,而VoIP的管理功能最多也只能算作初级水平。一旦出了问题,供应商缺乏解决问题的工具和技能。即便是能与ILEC展开竞争的新一代VoIP服务供应商也难以快速明确问题的原因并解决问题。

  6. Selective Oxidation of Alcohols Using Photoactive VO@g‑C3N4

    Data.gov (United States)

    U.S. Environmental Protection Agency — A photoactive VO@g-C3N4 catalyst has been developed for the selective oxidation of alcohols to the corresponding aldehydes and ketones. The visible light mediated...

  7. Business Collaborations in Grids: The BREIN Architectural Principals and VO Model

    Science.gov (United States)

    Taylor, Steve; Surridge, Mike; Laria, Giuseppe; Ritrovato, Pierluigi; Schubert, Lutz

    We describe the business-oriented architectural principles of the EC FP7 project “BREIN” for service-based computing. The architecture is founded on principles of how real businesses interact to mutual benefit, and we show how these can be applied to SOA and Grid computing. We present building blocks that can be composed in many ways to produce different value systems and supply chains for the provision of computing services over the Internet. We also introduce the complementary BREIN VO concept, which is centric to, and managed by, a main contractor who bears the responsibility for the whole VO. The BREIN VO has an execution lifecycle for the creation and operation of the VO, and we have related this to an application-focused workflow involving steps that provide real end-user value. We show how this can be applied to an engineering simulation application and how the workflow can be adapted should the need arise.

  8. Electrical and Seebeck effect measurements in Nb doped VO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, B. (Technion-Israel Inst. of Tech., Haifa)

    1982-01-01

    The resistance of pure and Nb doped VO/sub 2/ and the Seebeck coefficient of Nb doped VO/sub 2/ have been measured in the temperature range of 78 to 360 K. A simple analysis of the results shows that above 140 K and below the transition temperature the effective density of states in the conduction band of VO/sub 2/ is of the order of (but larger than) one state per vanadium atom. This high effective density of states is consistent with the large effective mass (and low mobility) of electrons in this material. It is shown also that in this range, the temperature dependence of the electronic mobility in VO/sub 2/ is Tsup(-..gamma..) where ..gamma.. > approximately 2. Additional results are discussed in the text.

  9. Predictors of VO2Peak in children age 6- to 7-years-old

    DEFF Research Database (Denmark)

    Dencker, Magnus; Hermansen, Bianca; Bugge, Anna

    2011-01-01

    This study investigated the predictors of aerobic fitness (VO2PEAK) in young children on a population-base. Participants were 436 children (229 boys and 207 girls) aged 6.7 ± 0.4 yrs. VO2PEAK was measured during a maximal treadmill exercise test. Physical activity was assessed by accelerometers....... Total body fat and total fat free mass were estimated from skinfold measurements. Regression analyses indicated that significant predictors for VO2PEAK per kilogram body mass were total body fat, maximal heart rate, sex, and age. Physical activity explained an additional 4-7%. Further analyses showed...... the main contributing factors for absolute values of VO2PEAK were fat free mass, maximal heart rate, sex, and age. Physical activity explained an additional 3-6%....

  10. Video Conference Based on VoIP MCU Subsystem Design%基于VoIP视频会议的MCU子系统设计

    Institute of Scientific and Technical Information of China (English)

    周康; 雷建锋

    2012-01-01

    Based on the VoIP network phone concept as well as the video conference presentations, as well as the VoIP in video conference system has been widely used. MCU video conference is core component, it can be said to be a video conference in the brain, in a video conferencing system, MCU(multipoint control unit) the main function is to coordinate and control the plurality of terminal of video transmission. This article is from the video conference system is the core component of the MCU subsystem of. On the function of the MCU and MCU and VoIP signaling conversion to the design of the system. System in the VC+ + 6 development platform, using C/S mode.%通过对VoIP网络电话的概念以及视频会议的介绍,以及当今视频会议系统中VoIP被广泛应用.MCU是视频会议的核心组成部分,它可以说是视频会议的大脑,在视频会议系统中,MCU(多点控制单元)主要功能是协调及控制多个终端间的视讯传输.文章主要是从视频会议系统最核心的组成部分MCU子系统人手.对MCU功能以及MCU和VoIP信令转换方面来设计该系统.系统是在VC++6.0平台下开发,采用C/S模式实现的.

  11. Predicting maximal aerobic capacity (VO2max) from the critical velocity test in female collegiate rowers.

    Science.gov (United States)

    Kendall, Kristina L; Fukuda, David H; Smith, Abbie E; Cramer, Joel T; Stout, Jeffrey R

    2012-03-01

    The objective of this study was to examine the relationship between the critical velocity (CV) test and maximal oxygen consumption (VO2max) and develop a regression equation to predict VO2max based on the CV test in female collegiate rowers. Thirty-five female (mean ± SD; age, 19.38 ± 1.3 years; height, 170.27 ± 6.07 cm; body mass, 69.58 ± 0.3 1 kg) collegiate rowers performed 2 incremental VO2max tests to volitional exhaustion on a Concept II Model D rowing ergometer to determine VO2max. After a 72-hour rest period, each rower completed 4 time trials at varying distances for the determination of CV and anaerobic rowing capacity (ARC). A positive correlation was observed between CV and absolute VO2max (r = 0.775, p < 0.001) and ARC and absolute VO2max (r = 0.414, p = 0.040). Based on the significant correlation analysis, a linear regression equation was developed to predict the absolute VO2max from CV and ARC (absolute VO2max = 1.579[CV] + 0.008[ARC] - 3.838; standard error of the estimate [SEE] = 0.192 L·min(-1)). Cross validation analyses were performed using an independent sample of 10 rowers. There was no significant difference between the mean predicted VO2max (3.02 L·min(-1)) and the observed VO2max (3.10 L·min(-1)). The constant error, SEE and validity coefficient (r) were 0.076 L·min(-1), 0.144 L·min(-1), and 0.72, respectively. The total error value was 0.155 L·min(-1). The positive relationship between CV, ARC, and VO2max suggests that the CV test may be a practical alternative to measuring the maximal oxygen uptake in the absence of a metabolic cart. Additional studies are needed to validate the regression equation using a larger sample size and different populations (junior- and senior-level female rowers) and to determine the accuracy of the equation in tracking changes after a training intervention.

  12. Effect of Preparation Parameters on Photoactivity of BiVO4 by Hydrothermal Method

    OpenAIRE

    Qingyun Chen; Miao Zhou; Di Ma; Dengwei Jing

    2012-01-01

    Bismuth vanadate (BiVO4) was synthesized from a mixture of aqueous Bi(NO3)3 and NH4VO3 solutions by using hydrothermal method. Via conducting the orthogonal experiments and single-factor experiments, the best synthetic parameters were determined. The physical and photophysical properties of the as-obtained samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-Vis diffusion reflectance spectroscopy (UV-Vis). Th...

  13. Broadband terahertz generation using the semiconductor-metal transition in VO2

    Directory of Open Access Journals (Sweden)

    Nicholas A. Charipar

    2016-01-01

    Full Text Available We report the design, fabrication, and characterization of broadband terahertz emitters based on the semiconductor-metal transition in thin film VO2 (vanadium dioxide. With the appropriate geometry, picosecond electrical pulses are generated by illuminating 120 nm thick VO2 with 280 fs pulses from a femtosecond laser. These ultrafast electrical pulses are used to drive a simple dipole antenna, generating broadband terahertz radiation.

  14. Broadband terahertz generation using the semiconductor-metal transition in VO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Charipar, Nicholas A., E-mail: nicholas.charipar@nrl.navy.mil; Kim, Heungsoo; Mathews, Scott A.; Piqué, Alberto [Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC, 20375 (United States)

    2016-01-15

    We report the design, fabrication, and characterization of broadband terahertz emitters based on the semiconductor-metal transition in thin film VO{sub 2} (vanadium dioxide). With the appropriate geometry, picosecond electrical pulses are generated by illuminating 120 nm thick VO{sub 2} with 280 fs pulses from a femtosecond laser. These ultrafast electrical pulses are used to drive a simple dipole antenna, generating broadband terahertz radiation.

  15. Resistance modulation in VO2 nanowires induced by an electric field via air-gap gates

    Science.gov (United States)

    Kanki, Teruo; Chikanari, Masashi; Wei, Tingting; Tanaka, Hidekazu; The Institute of Scientific; Industrial Research Team

    Vanadium dioxide (VO2) shows huge resistance change with metal-insulator transition (MIT) at around room temperature. Controlling of the MIT by applying an electric field is a topical ongoing research toward the realization of Mott transistor. In this study, we have successfully switched channel resistance of VO2 nano-wire channels by a pure electrostatic field effect using a side-gate-type field-effect transistor (SG-FET) viaair gap and found that single crystalline VO2 nanowires and the channels with narrower width enhance transport modulation rate. The rate of change in resistance ((R0-R)/R, where R0 and R is the resistance of VO2 channel with off state and on state gate voltage (VG) , respectively) was 0.42 % at VG = 30 V in in-plane poly-crystalline VO2 channels on Al2O3(0001) substrates, while the rate in single crystalline channels on TiO2 (001) substrates was 3.84 %, which was 9 times higher than that using the poly-crystalline channels. With reducing wire width from 3000 nm to 400 nm of VO2 on TiO2 (001) substrate, furthermore, resistance modulation ratio enhanced from 0.67 % to 3.84 %. This change can not be explained by a simple free-electron model. In this presentation, we will compare the electronic properties between in-plane polycrystalline VO2 on Al2O3 (0001) and single crystalline VO2 on TiO2 (001) substrates, and show experimental data in detail..

  16. Size and composition-controlled fabrication of VO2 nanocrystals by terminated cluster growth

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Slack, Jonathan

    2013-05-14

    A physical vapor deposition-based route for the fabrication of VO2 nanoparticles is demonstrated, consisting of reactive sputtering and vapor condensation at elevated pressures. The oxidation of vanadium atoms is an efficient heterogeneous nucleation method, leading to high nanoparticle throughtput. Fine control of the nanoparticle size and composition is obtained. Post growth annealing leads to crystalline VO2 nanoparticles with optimum thermocromic and plasmonic properties.

  17. Influence of nitrate supplementation on VO(2) kinetics and endurance of elite cyclists

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Nyberg, Michael Permin; Bangsbo, Jens

    2013-01-01

    The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72¿±¿4¿mL O(2) /kg/min, mean¿±¿standard deviation) underwent testing for VO(2) kinetics (3¿×¿6¿min at 298¿±¿28¿W...

  18. Determining the role of TiO/VO in hot exoplanet atmospheres

    Science.gov (United States)

    Evans, Thomas

    2016-10-01

    The role of TiO and VO in ultra hot (>2000K) gas giant atmospheres is a major unresolved issue in the exoplanet field. At these temperatures, TiO and VO are known to be important absorbers in the atmospheres of M/L dwarfs and have been theorized to play an important role in irradiated gas giants. To date, however, TiO/VO has not been securely detected in a planetary atmosphere, despite numerous searches. One possibility is that the upper atmospheres of highly irradiated planets are typically depleted of TiO/VO by cold-trapping at lower altitudes or rain-out on the relatively cool nightside. Using WFC3 G141 and ground-based photometry, we have recently published a transmission spectrum for WASP-121b (T~2400K) showing new evidence for absorption by TiO/VO. Our observations also yielded a high confidence (5.4 sigma) detection of the 1.4 micron H2O absorption band. The TiO/VO claim, however, remains tentative, as it currently hinges upon broadband photometry measurements obtained from the ground at relatively low signal-to-noise. If TiO/VO is present it will have significant implications for the overall physics and chemistry of the atmosphere, including the likely production of a strong thermal inversion in the upper atmosphere. I will describe the follow-up observations we are currently pursuing in order to confirm or rule out TiO/VO in the atmosphere of WASP-121b and in doing so address a long-standing mystery of exoplanet atmospheres.

  19. Effects of muscle electrical stimulation on peak VO2 in cardiac transplant patients.

    Science.gov (United States)

    Vaquero, A F; Chicharro, J L; Gil, L; Ruiz, M P; Sánchez, V; Lucía, A; Urrea, S; Gómez, M A

    1998-07-01

    Peak oxygen consumption (peak VO2) has become a critical component in the evaluation of heart transplant recipients (HTR). In these patients, peak VO2 remains low after cardiac transplantation mainly because of persisting peripheral limitations in the working muscles. Muscular electrical stimulation, on the other hand, has been shown to enhance the oxidative capacity of healthy muscle. It was the purpose of our investigation to study the effects of ES on the peak VO2 of HTR. Fourteen (11 males and 3 females) HTR (age: 57+/-7yr, mean +/- SD; height: 163+/-7 cm, weight: 70.5+/-8.6 kg) were selected as subjects and each of them was randomly assigned to one of two groups: (a) group EXP (n = 7), receiving electrical stimulation on both quadriceps muscles during a period of 8 weeks, and (b) group CONT (n = 7), not receiving electrical stimulation. Before (PRE) and after (POST) the aforementioned 8-week period, respectively, all the subjects performed a cardiopulmonary exercise test (ramp protocol) on a cycle ergometer for peak VO2 determination. PRE values of peak VO2 were similar in both groups (17.1+/-2.0 vs 16.9+/-3.8ml x kg(-1) x min(-1) in EXP and CONT, respectively). However, peak values of VO2 significantly increased in EXP (p < 0.05) after the period of electrical stimulation (POST peak VO2: 18.7+/-2.0ml x kg(-1)), whereas no change was observed in CONT (POST peak VO2: 16.2+/-3.2 ml x kg(-1) x min(-1)). In conclusion, electrical stimulation could therefore be used to improve the functional capacity of HTR, and might be included in the rehabilitation programs of this population group.

  20. 采用STLC1502的小型VoIP用户网关设计

    Institute of Scientific and Technical Information of China (English)

    徐华根; 贺科峰

    2005-01-01

    STLC1502是基于ST公司的专用于开发VoIP相关产品的处理器.是集成了ARM7和D950的双核芯片。普通双音频电话机可通过以STLC1502为核心的VoIP小型用户网关接入Intrnet.实现IP电话呼叫。

  1. 关于VoIP基本安全策略的探讨%Research on Basic Security Strategy of VoIP

    Institute of Scientific and Technical Information of China (English)

    张铁君; 王志强; 徐丽娜; 朱梓豪

    2010-01-01

    为确保VoIP(Voice over Internet Protocol)系统的安全,针对基于互联网的IP(Internet Protocol)电话发展与普及过程出现的安全问题进行了讨论,并在分析现有网络业存在的安全威胁的基础上,对企业部署VoIP时可能出现的安全问题给出了相应的安全建议.

  2. In Situ Electrical Conductivity Study of FeVO4 Catalyst%FeVO4催化剂的原位电导研究

    Institute of Scientific and Technical Information of China (English)

    徐爱菊; 照日格图; 贾美林; 林勤

    2008-01-01

    采用盐类固体研磨法制备了FeVO4催化剂,用原位电导方法测定了 FeVO4催化剂在氧气+丙烷→氧气→丙烷连续变化气氛下的电导变化,确定其导电类型.以BET、XRD、H2-TPR等技术对催化剂进行表征,研究了其对丙烷氧化脱氢制丙烯反应的催化性能.

  3. A comparison of time to exhaustion at VO2 max in élite cyclists, kayak paddlers, swimmers and runners.

    Science.gov (United States)

    Billat, V; Faina, M; Sardella, F; Marini, C; Fanton, F; Lupo, S; Faccini, P; de Angelis, M; Koralsztein, J P; Dalmonte, A

    1996-02-01

    A recent study has shown the reproducibility of time to exhaustion (time limit: tlim) at the lowest velocity that elicits the maximal oxygen consumption (vVO2 max). The same study found an inverse relationship between this time to exhaustion at vVO2 max and vVO2 max among 38 élite long-distance runners (Billat et al. 1994b). The purpose of the present study was to compare the time to exhaustion at the power output (or velocity) at VO2 max for different values of VO2 max, depending on the type of exercise and not only on the aerobic capacity. The time of exhaustion at vVO2 max (tlim) has been measured among 41 élite (national level) sportsmen: 9 cyclists, 9 kayak paddlers, 9 swimmers and 14 runners using specific ergometers. Velocity or power at VO2 max (vVO2 max) was determined by continuous incremental testing. This protocol had steps of 2 min and increments of 50 W, 30 W, 0.05 m s-1 and 2 km-1 for cyclists, kayak paddlers, swimmers and runners, respectively. One week later, tlim was determined under the same conditions. After a warm-up of 10 min at 60% of their vVO2 max, subjects were concluded (in less than 45 s) to their vVO2 max and then had to sustain it as long as possible until exhaustion. Mean values of vVO2 max and tlim were respectively equal to 419 +/- 49 W (tlim = 222 +/- 91 s), 239 +/- 56 W (tlim = 376 +/- 134 s), 1.46 +/- 0.09 m s-1 (tlim = 287 +/- 160 s) and 22.4 +/- 0.8 km h-1 (tlim = 321 +/- 84 s), for cyclists, kayak paddlers, swimmers and runners. Time to exhaustion at vVO2 max was only significantly different between cycling and kayaking (ANOVA test, p < 0.05). Otherwise, VO2 max (expressed in ml min-1 kg-1) was significantly different between all sports except between cycling and running (p < 0.05). In this study, time to exhaustion at vVO2 max was also inversely related to VO2 max for the entire group of élite sportsmen (r = -0.320, p < 0.05, n = 41). The inverse relationship between VO2 max and tlim at vVO2 max has to be explained, it

  4. Influence of lattice distortion on phase transition properties of polycrystalline VO2 thin film

    Science.gov (United States)

    Lin, Tiegui; Wang, Langping; Wang, Xiaofeng; Zhang, Yufen; Yu, Yonghao

    2016-08-01

    In this work, high power impulse magnetron sputtering was used to control the lattice distortion in polycrystalline VO2 thin film. SEM images revealed that all the VO2 thin films had crystallite sizes of below 20 nm, and similar configurations. UV-vis-near IR transmittance spectra measured at different temperatures showed that most of the as-deposited films had a typical metal-insulator transition. Four-point probe resistivity results showed that the transition temperature of the films varied from 54.5 to 32 °C. The X-ray diffraction (XRD) patterns of the as-deposited films revealed that most were polycrystalline monoclinic VO2. The XRD results also confirmed that the lattice distortions in the as-deposited films were different, and the transition temperature decreased with the difference between the interplanar spacing of the as-deposited thin film and standard rutile VO2. Furthermore, a room temperature rutile VO2 thin film was successfully synthesized when this difference was small enough. Additionally, XRD patterns measured at varied temperatures revealed that the phase transition process of the polycrystalline VO2 thin film was a coordinative deformation between grains with different orientations. The main structural change during the phase transition was a gradual shift in interplanar spacing with temperature.

  5. Monoclinic BiVO{sub 4} with regular morphologies: Hydrothermal synthesis, characterization and photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Li Haibin [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)], E-mail: coastllee@hotmail.com; Liu Guocong [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Department of Chemistry, Yulin Normal University, Yulin 537000 (China); Duan Xuechen [School of Materials Science and Engineering, Central South University, Changsha 410083 (China)

    2009-05-15

    Monoclinic bismuth vanadate (BiVO{sub 4}) samples with regular morphologies were prepared by a facile hydrothermal process with Bi{sub 2}O{sub 3} and NH{sub 4}VO{sub 3} as starting materials. The physical and photophysical properties of the as-prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR), and UV-vis diffuse reflectance spectroscopy (UV-vis). It was found that cuboid-like, square plate-like and flower-like BiVO{sub 4} could be readily obtained by tailoring the pH values of the reaction suspensions in the presence of CTAB. Both pH value and CTAB played crucial roles in the morphology evolution of the as-prepared samples. The bandgaps (E{sub g}) of cuboid-like, square plate-like and flower-like BiVO{sub 4} were 2.39 eV, 2.40 eV and 2.46 eV, respectively. The photocatalytic performance of the as-prepared BiVO{sub 4} was much better than that of P25 for photodegradation of methyl orange under sunlight irradiation. The photocatalytic activities of BiVO{sub 4} samples were highly related to their crystallinities and shapes.

  6. Mechanochemical synthesis of nanostructured BiVO{sub 4} and investigations of related features

    Energy Technology Data Exchange (ETDEWEB)

    Venkatesan, R. [Nanoscience and Nanotechnology program, CINVESTAV-IPN, Zacatenco, Av IPN 2508, Col Zacatenco, D.F., C.P. 07360 (Mexico); Institute of Molecules and Materials of Le Mans (IMMM) UMR CNRS, Universite du Maine, 72085 Le Mans (France); Velumani, S., E-mail: velu@cinvestav.mx [Nanoscience and Nanotechnology program, CINVESTAV-IPN, Zacatenco, Av IPN 2508, Col Zacatenco, D.F., C.P. 07360 (Mexico); Department of Electrical Engineering (SEES), CINVESTAV-IPN, Zacatenco, Av IPN 2508, Col Zacatenco, D.F., C.P. 07360 (Mexico); Kassiba, A., E-mail: kassiba@univ-lemans.fr [Institute of Molecules and Materials of Le Mans (IMMM) UMR CNRS, Universite du Maine, 72085 Le Mans (France)

    2012-08-15

    Highly crystalline monoclinic bismuth vanadate (BiVO{sub 4}) nanopowders with crystallite sizes less than 50 nm were obtained by mechanical milling of a stoichiometric mixture of bismuth oxide (Bi{sub 2}O{sub 3}) and vanadium pentoxide (V{sub 2}O{sub 5}). Different synthesized batches were obtained by varying the preparation times and the number of the tungsten carbide balls (BPR) while keeping constant the jar rotation speed. Annealing treatments were performed on the obtained nanopowders in order to improve the crystalline order and the BiVO{sub 4} nanoparticles surface states. Characterizations methods, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) equipped with X-ray energy dispersive spectrometer (EDS), Raman spectrometry, FTIR and UV-Vis diffuse reflectance techniques were used to shed light on the structure, morphologies and composition of the obtained nanopowders. Even if monoclinic BiVO{sub 4} crystalline structure was stabilized in samples after appropriate annealing, shifts of Raman peak positions after such treatments revealed the occurrence of symmetry distortions in the local structure of the monoclinic phase. -- Graphical abstract: Art Work - BiVO{sub 4} Synthesis and Structures. Highlights: Black-Right-Pointing-Pointer Synthesis by ball-milling of original nanostructures of BiVO{sub 4}. Black-Right-Pointing-Pointer Stabilizing a monoclinic BiVO{sub 4} polytype with nanoparticle sizes about 20 nm. Black-Right-Pointing-Pointer Investigations of annealing effects on structures, vibration and optical features.

  7. Visible light photocatalytic activity of BiVO4 particles with different morphologies

    Science.gov (United States)

    Lin, Xue; Yu, Lili; Yan, Lina; Li, Hongji; Yan, Yongsheng; Liu, Chunbo; Zhai, Hongju

    2014-06-01

    Bismuth vanadate (BiVO4) particles with different morphologies were synthesized by a one-step hydrothermal process and their optical and photocatalytic properties were investigated. Their crystal structure and microstructures were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). XRD patterns demonstrate that the as-prepared samples are monoclinic cell. FESEM shows that BiVO4 crystals can be fabricated in different morphologies by simply manipulating the reaction parameters of hydrothermal process. The UV-visible diffuse reflectance spectra (UV-vis DRS) reveal that the band gaps of BiVO4 photocatalysts are about 2.07-2.21 eV. The as-prepared BiVO4 photocatalysts exhibit higher photocatalytic activities in the degradation of rhodamine B (Rh B) under visible light irradiation (λ > 420 nm) compared with traditional N-doped TiO2 (N-TiO2). Furthermore, wheat like BiVO4 sample reveals the highest photocatalytic activity. Up to 100% Rh B is decolorized after visible light irradiation for 180 min. The reason for the difference in the photocatalytic activities for BiVO4 samples obtained at different conditions were systematically studied based on their shape, size and the variation of local structure.

  8. Formation energies of intrinsic point defects in monoclinic VO2 studied by first-principles calculations

    Science.gov (United States)

    Cui, Yuanyuan; Liu, Bin; Chen, Lanli; Luo, Hongjie; Gao, Yanfeng

    2016-10-01

    VO2 is an attractive candidate for intelligent windows and thermal sensors. There are challenges for developing VO2-based devices, since the properties of monoclinic VO2 are very sensitive to its intrinsic point defects. In this work, the formation energies of the intrinsic point defects in monoclinic VO2 were studied through the first-principles calculations. Vacancies, interstitials, as well as antisites at various charge states were taken into consideration, and the finite-size supercell correction scheme was adopted as the charge correction scheme. Our calculation results show that the oxygen interstitial and oxygen vacancy are the most abundant intrinsic defects in the oxygen rich and oxygen deficient condition, respectively, indicating a consistency with the experimental results. The calculation results suggest that the oxygen interstitial or oxygen vacancy is correlated with the charge localization, which can introduce holes or electrons as free carriers and subsequently narrow the band gap of monoclinic VO2. These calculations and interpretations concerning the intrinsic point defects would be helpful for developing VO2-based devices through defect modifications.

  9. Soft-chemical synthesis and high-temperature electrochemical characteristics of VO2

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ke-chao; CAO Du-meng; LI Zhi-you

    2006-01-01

    VO2 powder was synthesized by a new soft-chemical method using formaldehyde as a reductant. The influences of pyrolysis temperature and time on the phase and morphology of grains were investigated by using thermal gravimeter/differential thermal analysis(TG/DTA), X-ray diffraction(XRD), Fourier transform infrared(FTIR) spectroscopy and scanning electron microscope(SEM). The positive electrode discharge performances of Li-B/LiCl-KCl/VO2 thermal battery at 500 ℃ were studied. The results show that the product is mainly non-crystal when the precursor of VO2 is heated below 300 ℃. VO2(B) appears and transits into VO2(R) irreversibly as the heating temperature rises. The open-circle voltage of VO2 is 2.6 V (vs Li-B), and the initial discharge voltage of 100 mA/cm2 at 500 ℃ is 2.52 V. The specific capacities of 100 mA/cm2 and 200 mA/cm2 at cut-off voltage of 1.4 V are 449 A·s/g and 539 A·s/g, respectively.

  10. Tailoring Multilayered BiVO4 Photoanodes by Pulsed Laser Deposition for Water Splitting.

    Science.gov (United States)

    Murcia-López, Sebastián; Fàbrega, Cristian; Monllor-Satoca, Damián; Hernández-Alonso, María D; Penelas-Pérez, Germán; Morata, Alex; Morante, Juan R; Andreu, Teresa

    2016-02-17

    Pulsed laser deposition (PLD) is proposed as promising technique for the fabrication of multilayered BiVO4-based photoanodes. For this purpose, bare BiVO4 films and two heterojunctions, BiVO4/SnO2 and BiVO4/WO3/SnO2, have been prepared using consecutive ablation of assorted targets in a single batch. The ease, high versatility and usefulness of this technique in engineering the internal configuration of the photoanode with stoichiometric target-to-substrate transfer are demonstrated. The obtained photocurrent densities are among the highest reported values for undoped BiVO4 without oxygen evolution catalysts (OEC). A detailed analysis of the influence of SnO2 and WO3 layers on the charge transport properties because of the changes at the internal FTO/semiconductor interface is performed through transient photocurrent measurements (TPC), showing that the BiVO4/WO3/SnO2 heterostructure attains a significant decrease in the internal losses and reaches high photocurrent values. This study is expected to open the door to the fabrication of other systems based on ternary (or even more complex) metal oxides as photoanodes for water splitting, which is a promising alternative for obtaining materials able to fulfill the different requierements in the development of more efficient systems for this process.

  11. Association of VO2 and VCO2 rate variability with serum glucose, insulin, and glucose intolerance.

    Science.gov (United States)

    Satué-Rodríguez, Julián; Méndez, José D

    2012-08-01

    Changes in the cellular metabolism assessed by the variability of oxygen consumption (VO(2) ) and carbon dioxide production (VCO(2) ) as well as the association of serum glucose and insulin to energy spectral density (ESD) of VO(2) and VCO(2) were evaluated. Ten nonglucose intolerant and 10 glucose intolerant subjects, aged 21-70 years, were included. Glucose and insulin concentrations and VO(2) and VCO(2) records were collected every 10 min during 3 h. ESD of VO(2) and VCO(2) was estimated and associated with glucose and insulin concentrations. Statistical significance in glucose levels, insulin, and ESD of VO(2) and VCO(2) among nonglucose intolerant subjects and glucose and insulin among glucose intolerance subjects at postload glucose (PLG) state compared with basal state was found. Moreover, glucose was significantly higher in glucose intolerance subjects than nonglucose intolerant subjects for basal and PLG states. These results show an increment in ESD of VO(2) and VCO(2) at PLG state among nonglucose intolerant subjects and suggest that their measurement may be a key indicator of the variability of cellular metabolic activity and contribute to confirm disturbances in glucose metabolism.

  12. Activation of peroxymonosulfate by BiVO4 under visible light for degradation of Rhodamine B

    Science.gov (United States)

    Liu, Yang; Guo, Hongguang; Zhang, Yongli; Tang, Weihong; Cheng, Xin; Liu, Hongwei

    2016-06-01

    A photocatalytic system involving visible light and BiVO4 (Vis/BiVO4) in the presence of peroxymonosulfate (PMS) has been developed to oxidize the target pollutant Rhodamine B (RhB) in aqueous solution. It was found that PMS could enhance the photocatalytic efficiency of BiVO4 and could be activated to promote the removal of RhB with sulfate radicals, hydroxyl radicals and superoxide radicals. Critical impacting factors in the Vis/BiVO4/PMS system were investigated concerning the influence of PMS concentration, solution pH, catalyst dosage, initial concentration of RhB and the presence of anions (Cl- and CO32-). In addition, by using isopropanol, tert-butanol, 1,4-benzoquinone and ethylenediamine tetraacetic acid disodium salt as probe compounds, the main active species were demonstrated including radSO4-, radOH and radO2- in the system, and a detail photocatalytic mechanism for the Vis/BiVO4/PMS system was proposed. Finally, up to 10 intermediate products of RhB were identified by GC/MS, included benzenoid organic compounds, organic acids and three nitrogenous organic compounds. This study provides a feasible way to degrade organic pollutants in wastewater using BiVO4 with PMS under visible light.

  13. Reversible phase modulation and hydrogen storage in multivalent VO2 epitaxial thin films

    Science.gov (United States)

    Yoon, Hyojin; Choi, Minseok; Lim, Tae-Won; Kwon, Hyunah; Ihm, Kyuwook; Kim, Jong Kyu; Choi, Si-Young; Son, Junwoo

    2016-10-01

    Hydrogen, the smallest and the lightest atomic element, is reversibly incorporated into interstitial sites in vanadium dioxide (VO2), a correlated oxide with a 3d1 electronic configuration, and induces electronic phase modulation. It is widely reported that low hydrogen concentrations stabilize the metallic phase, but the understanding of hydrogen in the high doping regime is limited. Here, we demonstrate that as many as two hydrogen atoms can be incorporated into each VO2 unit cell, and that hydrogen is reversibly absorbed into, and released from, VO2 without destroying its lattice framework. This hydrogenation process allows us to elucidate electronic phase modulation of vanadium oxyhydride, demonstrating two-step insulator (VO2)-metal (HxVO2)-insulator (HVO2) phase modulation during inter-integer d-band filling. Our finding suggests the possibility of reversible and dynamic control of topotactic phase modulation in VO2 and opens up the potential application in proton-based Mottronics and novel hydrogen storage.

  14. The Multimission Archive at the Space Telescope Science Institute in the context of VO activities

    CERN Document Server

    Kamp, I; Conti, A; Fraquelli, D; Kimball, T; Levay, K; Shiao, B; Smith, M; Somerville, R S; White, R L; Kamp, Inga; Thompson, Randall; Conti, Alberto; Fraquelli, Dorothy; Kimball, Tim; Levay, Karen; Shiao, Bernie; Smith, Myron; Somerville, Rachel; White, Richard L.

    2004-01-01

    In the past year, the Multimission Archive at the Space Telescope Science Institute (MAST) has taken major steps in making MAST's holdings available using VO-defined protocols and standards, and in implementing VO-based tools. For example, MAST has implemented the Simple Cone Search protocol, and all MAST mission searches may be returned in the VOTable format, allowing other archives to use MAST data for their VO applications. We have made many of our popular High Level Science Products available through Simple Image Access Protocol (SIAP), and are implementing the VO Simple Spectral Access Protocol (SSAP). The cross correlation of VizieR catalogs with MAST missions is now possible, and illustrates the integration of VO services into MAST. The user can easily display the results from searches within MAST using the plotting tool VOPlot. MAST also participates in the NVO registry service. Thus, the user can harvest MAST holdings simultaneously with data from many other surveys and missions through the VO DataSc...

  15. Controlled Synthesis and Photocatalytic Antifouling Properties of BiVO4 with Tunable Morphologies

    Science.gov (United States)

    Xiang, Zhenbo; Wang, Yi; Ju, Peng; Zhang, Dun

    2017-02-01

    Monoclinic BiVO4 with different nanostructures were prepared via a facile and rapid route by adding different surfactants. Ethylenediaminetetraacetic acid, polyvinylpyrrolidone, and sodium dodecyl sulfate surfactants were selected as morphology controlling agents. The crystal phase, morphology, and diffuse reflectance spectra of BiVO4 were characterized by x-ray diffraction, scanning electron microscopy, and UV-visible diffuse reflectance spectra techniques, respectively. The photocatalytic activities of BiVO4 were investigated by killing the typical marine fouling bacteria Pseudomonas aeruginosa ( P. aeruginosa) under visible light irradiation. BiVO4 with grape-like nanostructure exhibited the best photocatalytic bactericidal activity. The sterilization rate of P. aeruginosa could reach up to 99.9% in 120 min. The photocatalytic mechanism was studied by captive species trapping experiments. The result revealed that photogenerated hole (h+) is the main reactive specie for killing P. aeruginosa under visible light irradiation. In addition, after five recycles, BiVO4 does not exhibit significant loss of photocatalytic sterilization activity. The results confirm that the synthesized BiVO4 photocatalyst has long-time reusability and good photocatalytic stability.

  16. 基于3GPP R7 HSPA的VoIP技术

    Institute of Scientific and Technical Information of China (English)

    赵绍刚; 张炜

    2007-01-01

    基于HSPA的VoIP技术是目前3G研究一个热点问题,文章详细探讨了在3GPP R7 HSPA支持下的VoIP技术.研究结果表明,在同样端到端质量前提下,基于3GPP这个较高的VoIP频谱效率主要是因为3GPP在R5/R6/R7规范中对高级移动接收机算法和VoIP优化无线网络算法进行了优化.HSPA的VoIP频谱效率要高于基于电路交换的语音呼叫的频谱效率.研究还表明即使HSDPA没有软切换,HSPA的移动性解决方案仍然可以满足VoIP的需求.

  17. Continuous tuning of W-doped VO{sub 2} optical properties for terahertz analog applications

    Energy Technology Data Exchange (ETDEWEB)

    Karaoglan-Bebek, G. [Department of Physics and Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Hoque, M. N. F.; Fan, Z.; Bernussi, A. A., E-mail: ayrton.bernussi@ttu.edu [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Holtz, M. [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)

    2014-11-17

    Vanadium dioxide (VO{sub 2}), with its characteristic metal-insulator phase transition, is a prospective active candidate to realize tunable optical devices operating at terahertz (THz) frequencies. However, the abrupt phase transition restricts its practical use in analog-like continuous applications. Incorporation of tungsten is a feasible approach to alter the phase transition properties of thin VO{sub 2} films. We show that amplitude THz modulation depth of ∼65%, characteristic phase transition temperature of ∼40 °C, and tuning range larger than 35 °C can be achieved with W-doped VO{sub 2} films grown on sapphire substrates. W-doped VO{sub 2} films can also be used to suppress Fabry-Perot resonances at THz frequencies but at temperatures much lower than that observed for undoped VO{sub 2} films. The gradual phase transition temperature window allows for precise control of the W-doped VO{sub 2} optical properties for future analog based THz devices.

  18. On-line Monitoring of VoIP Quality Using IPFIX

    Directory of Open Access Journals (Sweden)

    Petr Matousek

    2014-01-01

    Full Text Available The main goal of VoIP services is to provide a reliable and high-quality voice transmission over packet networks. In order to prove the quality of VoIP transmission, several approaches were designed. In our approach, we are concerned about on-line monitoring of RTP and RTCP traffic. Based on these data, we are able to compute main VoIP quality metrics including jitter, delay, packet loss, and finally R-factor and MOS values. This technique of VoIP quality measuring can be directly incorporated into IPFIX monitoring framework where an IPFIX probe analyses RTP/RTCP packets, computes VoIP quality metrics, and adds these metrics into extended IPFIX flow records. Then, these extended data are stored in a central IPFIX monitoring system called collector where can be used for monitoring purposes. This paper presents a functional implementation of IPFIX plugin for VoIP quality measurement and compares the results with results obtained by other tools.

  19. VO-KOREL: A Fourier disentangling service of Virtual Observatory

    CERN Document Server

    Škoda, Petr; Fuchs, Jan

    2011-01-01

    VO-KOREL is a web service exploiting the technology of Virtual Observatory for providing the astronomers with the intuitive graphical front-end and distributed computing back-end running the most recent version of Fourier disentangling code KOREL. The system integrates the ideas of the e-shop basket, conserving the privacy of every user by transfer encryption and access authentication, with features of laboratory notebook, allowing the easy housekeeping of both input parameters and final results, as well as it explores a newly emerging technology of cloud computing. While the web-based front-end allows the user to submit data and parameter files, edit parameters, manage a job list, resubmit or cancel running jobs and mainly watching the text and graphical results of a disentangling process, the main part of the back-end is a simple job queue submission system executing in parallel multiple instances of FORTRAN code KOREL. This may be easily extended for GRID-based deployment on massively parallel computing cl...

  20. The Gaia Archive at ESAC: a VO-inside archive

    Science.gov (United States)

    Gonzalez-Nunez, J.

    2015-12-01

    The ESDC (ESAC Science Data Center) is one of the active members of the IVOA (International Virtual Observatory Alliance) that have defined a set of standards, libraries and concepts that allows to create flexible,scalable and interoperable architectures on the data archives development. In the case of astronomy science that involves the use of big catalogues, as in Gaia or Euclid, TAP, UWS and VOSpace standards can be used to create an architecture that allows the explotation of this valuable data from the community. Also, new challenges arise like the implementation of the new paradigm "move code close to the data", what can be partially obtained by the extension of the protocols (TAP+, UWS+, etc) or the languages (ADQL). We explain how we have used VO standards and libraries for the Gaia Archive that, not only have producing an open and interoperable archive but, also, minimizing the developement on certain areas. Also we will explain how we have extended these protocols and the future plans.

  1. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos

    Directory of Open Access Journals (Sweden)

    Eduardo Camillo Martinez

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condicionamento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adultos. MÉTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exército Brasileiro (42,6 ± 4,8 anos. Foram mensurados os níveis plasmáticos de adiponectina, massa corporal, estatura, circunferência da cintura (CC, percentual de gordura por pesagem hidrostática e VO2max por ergoespirometria. Um questionário foi utilizado para obter as características do treinamento físico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48% sujeitos apresentaram sobrepeso e 36 (14% eram obesos. Ainda, 66 sujeitos (27% apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relação aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram níveis de adiponectina mais altos que os demais. Os níveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento físico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlação dos níveis de adiponectina e do VO2max não permaneceu significante após controlada pelo IMC e CC. CONCLUSÃO: Sujeitos com melhor condicionamento cardiorrespiratório e com estado nutricional normal parecem apresentar níveis mais saudáveis de adiponectina.

  2. Inoculación de Burkholderia cepacia y Gluconacetobacter diazotrophicus sobre la fenología y biomasa de Triticum aestivum var. Nana F2007 a 50% de fertilizante nitrogenado

    Directory of Open Access Journals (Sweden)

    Jesús Jaime Hernández-Escareño

    2015-01-01

    Full Text Available El aumento en el consumo de Triticum aestivum (trigo var Nana-F2007 requiere de la aplicación de fertilizante nitrogenado (FN, como NH4NO3 (nitrato de amonio, él que en exceso causa la pérdida de fertilidad del suelo. Una alternativa para reducir y optimizar la dosis de FN en T. aestivum, es inocular su semilla con géneros de bacterias promotoras del crecimiento vegetal endófitas (BPCVE. Se sugiere que cuando éstas invaden internamente su raíz inducen la síntesis de sustancias promotoras de crecimiento vegetal (SPCV, que mejoran la absorción radical del FN. El objetivo de esta investigación fue evaluar el efecto de inoculación de Burkholderia cepacia y Gluconacetobacter diazotrophicus en la fenología y biomasa de T. aestivum a dosis 50% del FN. En invernadero la semilla de trigo se trató con ambos géneros de BPCVE. Con las variables respuesta: fenología: altura de planta, longitud de raíz y biomasa peso fresco/seco total aéreo y radical a plántula y floración. Los resultados mostraron que B. cepacia en T. aestivum causó un incremento en su peso seco total (PST con 0,61 g, valor estadísticamente significativo comparado con los 0,53 g del PST del trigo control relativo (CR con el FN al 100%. La combinación B. cepacia.-G. diazotrophicus en T. aestivum incrementó su PST con 4,23g, valor estadísticamente significativo comparado con los 1,13 g de PST del T. aestivum (CR. Lo anterior sugiere que B. cepacia y G. diazotrophicus mediante SPCV ejercieron un efecto positivo en la fenología y biomasa de T. aestivum a la dosis 50% del FN para esta variedad.

  3. 基于Asterisk的VoIP软电话研究与仿真%Study and simulation of VoIP softphone based on Asterisk

    Institute of Scientific and Technical Information of China (English)

    蒋华; 曲艳博; 潘文吉; 杨磊; 王坤

    2015-01-01

    为了使用Linux开源系统作为VoIP服务器,可以将可运行在Linux等系统上的IP分组交换机产品Asterisk作为开源软交换平台通信的VoIP语音网关。本文将Asterisk与Linux操作系统结合在一起,采用源码方式安装Asterisk作为服务器,通过配置conf等文件来注册用户。然后通过软电话在Asterisk服务器上注册,并进行了测试,最后给出了实验仿真的结果。%To use open source system like Linux to be the VoIP server, one can apply Asterisk, which can be run on several systems such as Linux as IP packet switch components, as VoIP voice gateway in the open source softswitch platform communication. This paper combines Asterisk and Linux, fixes Asterisk as server by adopting source code mode and configures files as conf to register users. Then we register softphones on the Asterisk server, and do the test, finally we give the results of simulation experiments.

  4. Design on PCM Timeslot Switching between VoIP and 2-wire Telephone%VoIP与二线电话的PCM时隙交换设计

    Institute of Scientific and Technical Information of China (English)

    宋桂景; 班亚明

    2012-01-01

    针对不同网络间的话音通信设计需求,论述了利用内嵌语音网关模块在网络电话(Voice over Internet Protocol,VoIP)与二线模拟电话之间进行话音脉冲编码调制(PCM)时隙交换的设计方案,给出了硬件实现原理和软件设计流程,对话音通信中内VoIP模块性能、PCM信号接口电平的稳定性以及模块间串口包通信的可靠性进行了详细分析。%Aiming at different design requirements of voice communication between network, this paper discusses the design scheme of voice pulse coding modulation (PCM) timeslot switching between VoIP and 2-wire analog telephone by using in-line tone gateway module. It presents the hardware implementation principle and software design process and analyzes in detail the in-line VoIP module performance in voice communication, interface level stability of PCM signal and serial communication reliability between modules.

  5. 基于SIP的VoIP系统在MANET中的应用研究%Application research on SIP-based VoIP system over MANET

    Institute of Scientific and Technical Information of China (English)

    俞凡

    2007-01-01

    由于MANET具有自组织、无中心等特点,传统的VoIP体系结构不能直接应用在MANET之上,这就要求对传统VoIP系统进行一定的改造,使之能够适应MANET环境.文章提出将P2P的簇状组网结构引入SIP,从而实现在MANET上构建基于SIP的可灵活扩展的VoIP通信系统;分析了在该架构中主要操作的典型工作机制,采用本方案的VoIP系统既可以适应MANET环境的需求,又可以与现有的SIP系统无缝通信;最后,展望了其未来的研究方向.

  6. Enhanced electrochemical performance of orientated VO2(B) raft-like nanobelt arrays through direct lithiation for lithium ion batteries

    Science.gov (United States)

    Liu, Liang; Liu, Qiang; Zhao, Wen; Li, Guochun; Wang, Limei; Shi, Weidong; Chen, Long

    2017-02-01

    Lithiation modification of VO2(B) has been carried out by a facile hydrothermal process, and the compact and locally ordered VO2(B) raft-like nanobelt arrays have been prepared. The synthesis route provides a new approach to elaborate a VO2(B) nanostructure under a mild environment condition. It is found that the growth mechanism of VO2(B) raft-like nanobelt arrays is different from the traditional nucleation-growth process. A novel chemical lithiating-exfoliating-splitting model is proposed. Compared with the bulk counterpart, the lithiated VO2(B) raft-like nanobelt arrays as cathodes exhibit a higher discharge capacity and an enhanced high-rate performance owing to their increased structural anisotropy and decreased polarization. This work indicates that VO2(B) raft-like nanobelt arrays have great potential applications as cathode materials for lithium ion batteries.

  7. Surface-doping effect of InVO4 nanoribbons and the distinctive behavior as gas sensors.

    Science.gov (United States)

    Liu, Shanshan; Hu, Fei; Zhang, Jie; Tang, Hanxiao; Shao, Mingwang

    2013-04-24

    Indium vanadate (InVO4) gas sensors were fabricated by depositing InVO4 nanoribbons aqueous suspension onto ceramic substrates. Their resistances distinctively increased in the detection of ammonia and propylamine, indicating an n-to-p semiconductor transition. This novel phenomenon of the InVO4-based sensor may be ascribed to the surface doping effect: electrons were trapped by H2O and O2 and produced OH(-) and O2(-) on the InVO4 surface, which resulted in holes overcompensation in the InVO4 valence band. Moreover, the sufficiently large surface-to-volume ratio of these nanoribbons enables fast carrier transfer on the sensor surface. The InVO4 nanoribbons-based sensors had optimum performance at room temperature and enjoyed good restorability. They also had great response to a wide range of target gas concentration, with ultrahigh sensitivities up to 1100% for ammonia and 760% for propylamine.

  8. Selective synthesis and visible-light photocatalytic activities of BiVO{sub 4} with different crystalline phases

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xi [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China); Ai Zhihui [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China)]. E-mail: jennifer.ai@mail.ccnu.edu.cn; Jia Falong [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China); Zhang Lizhi [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China)]. E-mail: zhanglz@mail.ccnu.edu.cn; Fan Xiaoxing [Ecomaterials and Renewable Energy Research Center (ERERC), Department of Physics, Nanjing University, Nanjing 210093 (China); Zou Zhigang [Ecomaterials and Renewable Energy Research Center (ERERC), Department of Physics, Nanjing University, Nanjing 210093 (China)

    2007-05-15

    Tetragonal and monoclinic bismuth vanadate (BiVO{sub 4}) powders were selectively synthesized by aqueous processes. The characterizations of the as-prepared BiVO{sub 4} powders were carried out by X-ray diffraction, nitrogen adsorption, scanning electron microscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic activities of different BiVO{sub 4} samples were determined by degradation of methylene blue solution under visible-light irradiation ({lambda} > 420 nm) and compared with that of TiO{sub 2} (Degussa P25). The band gaps of the as-prepared BiVO{sub 4} were determined from UV-vis diffuse reflectance spectra. It was found that monoclinic BiVO{sub 4} with a band gap of 2.34 eV showed higher photocatalytic activity than that of tetragonal BiVO{sub 4} with a band gap of 3.11 eV.

  9. A simple and low-cost combustion method to prepare monoclinic VO2 with superior thermochromic properties

    Science.gov (United States)

    Cao, Ziyi; Xiao, Xiudi; Lu, Xuanming; Zhan, Yongjun; Cheng, Haoliang; Xu, Gang

    2016-12-01

    In this approach, the VO2 nanoparticles have been successfully fabricated via combusting the low-cost precursor solution consisted of NH4VO3, C2H6O2 and C2H5OH. By the XRD, TEM and XPS analysis, it can be found that the synthetic monoclinic VO2 is single crystal and no impurity is defined. After dispersing the VO2 nanoparticles into the polymer, the solar modulation of VO2-based composite film is up to 12.5% with luminous transmission and haze around 62.2% and 0.5%, respectively. In other words, the composite films show high performance of thermochromic properties. This could open an efficient way to fabricate low-cost and large-scale VO2 (M) nanoparticles and thermochromic films.

  10. Determinación de carbono orgánico total presente en el suelo y la biomasa de los páramos de las comunidades de chimborazo y shobol llinllin en Ecuador

    Directory of Open Access Journals (Sweden)

    M. Echeverría

    2013-01-01

    Full Text Available En la determinación del contenido de carbono orgánico total presente en el suelo y la biomasa (cobertura vegetal de los páramos de las comunidades de Chimborazo, con 210ha de páramo cuya ubicación es 746667UTM-9825400UTM, y Shobol Llinllín, con 350 ha de páramo, 754680UTM–9854678UTM, pertenecientes a San Juan en Ecuador, se seleccionaron 9 puntos de muestreo de acuerdo a la variación, características y altitud del suelo, repartidos para este estudio en tres pisos altitudinales comprendidos, para el páramo de la comunidad Chimborazo, entre 3600-3900 msnm y, en el caso de Shobol Llinllín, entre 3600-3950 msnm.

  11. Composición química de la biomasa residual de la planta de piña variedad MD2 proveniente de Guácimo, Limón

    OpenAIRE

    Irías, Andrea; Lutz, Giselle

    2015-01-01

    Se determinó durante el mes de febrero del año 2009, el contenido de humedad, ligninas, holocelulosa, nitrógeno y minerales (potasio, calcio, hierro, magnesio, sodio) en la biomasa residual de la planta de piña variedad MD2 de la región de Guácimo, mediante los métodos extracción con disolventes, Kjeldahl y espectrometría de absorción atómica. Se observaron diferencias en la composición química reportada para cultivos de otras regiones, lo cual debe ser tomado en cuenta para el aprovechamient...

  12. Evaluación de los pretratamientos con ácido sulfúrico diluido y AFEX en la biomasa lignocelulósica del tipo pasto gigante “Pennisetum Sp”

    OpenAIRE

    Mateus Fontecha, Lady

    2011-01-01

    El objetivo de esta investigación fue estudiar la efectividad del pretratamiento con ácido sulfúrico diluido y la explosión de fibras con solución de amoníaco (AFEX) sobre la biomasa lignocelulósica de Pennisetum sp en la hidrólisis de carbohidratos fermentables para la producción de etanol. En el pretratamiento con ácido sulfúrico se estudio el efecto de la temperatura (110, 130, 150, 170 y 190 °C) y la concentración del ácido [0,8; 1,2 y 2,0 % (p/p)], mientras que en el pretratamiento AFEX ...

  13. Dinámica de la Biomasa Microbiana y su Relación con la Respiración y el Nitrógeno del Suelo en Tierras Agrícolas en el Valle del Mantaro

    OpenAIRE

    Hinostroza, Amanda; Universidad Alas Peruanas; Malca, Julio; Universidad Alas Peruanas; Suárez, Luis; Universidad Alas Peruanas

    2016-01-01

    Se estudió el efecto del abonamiento orgánico con estiércol de ganado vacuno, ovino, de cuy, fertilización química y sin abonamiento sobre la variación del nitrógeno, variación de la biomasa microbiana del suelo y la respiración del suelo en cultivos de papa (Solanum tuberosum) y maíz (Zea mays) durante la campaña agrícola 2009 en cuatro localidades del valle del Mantaro: El Mantaro, Chupaca, Santa Ana y Huayao, bajo diseño experimental de bloques completamente aleatorios con arreglo factoria...

  14. Captura de CO2 en centrales termoeléctricas mediante combustión de carbón y biomasa en condiciones de oxicombustión

    OpenAIRE

    Riaza Benito, Juan

    2016-01-01

    El carbón es y va a seguir siendo uno de los principales recursos energéticos para la generación de energía eléctrica. Sin embargo, en la combustión del carbón se libera CO2, que es un gas de efecto invernadero y el principal causante del cambio climático. Una alternativa para la reducción parcial de emisiones de CO2 consiste en sustituir parte del carbón utilizado en la combustión por biomasa, cuyas emisiones se consideran neutras. Sin embargo, para reducir de forma importante las emisiones ...

  15. EFECTO DEL CARBONATO DE POTASIO EN LA EVOLUCIÓN DE LOS GRUPOS FUNCIONALES DE LOS BIOCRUDOS DE CONVERSIÓN HIDROTÉRMICA DE BIOMASA LIGNOCELULÓSICA ALREDEDOR DEL PUNTO CRÍTICO DEL AGUA

    Directory of Open Access Journals (Sweden)

    José Díaz

    2009-04-01

    Full Text Available Un tipo de biomasa pobre en lignina, del género Pennisetum fue sometida al proceso de conversión hidrotérmica en presencia de carbonato de potasio como catalizador. Las reacciones se llevaron a cabo en ambientes cercanos al punto crítico del agua. Los productos de reacción no acuosos (biocrudo se separaron por decantación y se analizaron por espectrometría infrarroja. Los biocrudos obtenidos contienen compuestos con funcionalidades aromáticas, olefínicas, hidroxiladas, éteres, y para el caso del biocrudo obtenido bajo la condición subcrítica funciones carbonilo. La fracción gaseosa y el biocrudo aumentan en presencia del carbonato de potasio.   

  16. Efficient High Power Ho,Tm:GdVO4 Laser

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-Zhu; ZHU Guo-Li; JU You-Lun; YAO Bao-Quan

    2011-01-01

    We report a 22.3 W cw diode-pumped cryogenic Ho(0.5at. %), Tm(at.5%):GdVC>4 laser at a wavelength of 2.05 fzm. It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm, both of which provide 42 W pump power near 802 nm. A cw output power of 22.3 W was obtained at the pump power of 51.0 W, corresponding to an optical-to-optical conversion efficiency of 43.7% when the ratio of the pump beam to oscillating laser beam in the crystal was ^1.33:1. The M2 factor was found to be 2.0 under an output power of 16.5 W.%@@ We report a 22.3 W ew diode-pumped cryogenic Ho(0.5at.%),Tm(at.5%):GdVO4 laser at a wavelength of 2.05μm.It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm,both of which provide 42W pump power near 802 nm.A cw output power of 22.3 W was obtained at the pump power of 51.0W,corresponding to an optical-to-optical conversion efficiency of 43.7%when the ratio of the pump beam to oscillating laser beam in the crystal was ~1.33:1.The M2 factor was found to be 2.0 under an output power of 16.5 W.

  17. VoIP attacks detection engine based on neural network

    Science.gov (United States)

    Safarik, Jakub; Slachta, Jiri

    2015-05-01

    The security is crucial for any system nowadays, especially communications. One of the most successful protocols in the field of communication over IP networks is Session Initiation Protocol. It is an open-source project used by different kinds of applications, both open-source and proprietary. High penetration and text-based principle made SIP number one target in IP telephony infrastructure, so security of SIP server is essential. To keep up with hackers and to detect potential malicious attacks, security administrator needs to monitor and evaluate SIP traffic in the network. But monitoring and following evaluation could easily overwhelm the security administrator in networks, typically in networks with a number of SIP servers, users and logically or geographically separated networks. The proposed solution lies in automatic attack detection systems. The article covers detection of VoIP attacks through a distributed network of nodes. Then the gathered data analyze aggregation server with artificial neural network. Artificial neural network means multilayer perceptron network trained with a set of collected attacks. Attack data could also be preprocessed and verified with a self-organizing map. The source data is detected by distributed network of detection nodes. Each node contains a honeypot application and traffic monitoring mechanism. Aggregation of data from each node creates an input for neural networks. The automatic classification on a centralized server with low false positive detection reduce the cost of attack detection resources. The detection system uses modular design for easy deployment in final infrastructure. The centralized server collects and process detected traffic. It also maintains all detection nodes.

  18. Interaction of VO2+ ion with human serum transferrin and albumin.

    Science.gov (United States)

    Sanna, Daniele; Garribba, Eugenio; Micera, Giovanni

    2009-04-01

    The complexation of VO(2+) ion with the high molecular mass components of the blood serum, human serum transferrin (hTf) and albumin (HSA), has been re-examined using EPR spectroscopy. In the case of transferrin, the results confirm those previously obtained, showing that VO(2+) ion occupies three different binding sites, A, B(1) and B(2), distinguishable in the X-band anisotropic spectrum recorded in D(2)O. With albumin the results show that a dinuclear complex (VO)(2)(d)HSA is formed in equimolar aqueous solutions or with an excess of protein; in the presence of an excess of VO(2+), the multinuclear complex (VO)(x)(m)HSA is the prevalent species, where x=5-6 indicates the equivalents of metal ion coordinated by HSA. The structure of the dinuclear species is discussed and the donor atoms involved in the metal coordination are proposed on the basis of the measured EPR parameters. Two different binding modes of albumin can be distinguished varying the pH, with only one species being present at the physiological value. The results show that the previously named "strong" site is not the N-terminal copper binding site, and some hypothesis on the metal coordination is discussed, with the (51)V A(z) values for the proposed donor sets obtained by DFT (density functional theory) calculations. Finally, preliminary results obtained in the ternary system VO(2+)/hTf/HSA are shown in order to determine the different binding strength of the two proteins. Due to the low VO(2+) concentration used, the recording of the EPR spectra through the repeated acquisition of the weak signals is essential to obtain a good signal to noise ratio in these systems.

  19. Effects of electrical stimulation on VO2 kinetics and delta efficiency in healthy young men

    Science.gov (United States)

    Perez, M; Lucia, A; Santalla, A; Chicharro, J

    2003-01-01

    Objective: To determine the effects of electrical stimulation (ES) on oxygen uptake (VO2) kinetics and delta efficiency (DE) during gradual exercise. The hypothesis was that ES would attenuate the VO2-workload relation and improve DE. Methods: Fifteen healthy, untrained men (mean (SD) age 22 (5) years) were selected. Ten were electrostimulated on both quadriceps muscles with a frequency of 45–60 Hz, with 12 seconds of stimulation followed by eight seconds recovery for a total of 30 minutes a day, three days a week for six weeks. The remaining five subjects were assigned to a control group. A standardised exercise test on a cycle ergometer (ramp protocol, workload increases of 20 W/min) was performed by each subject before and after the experimental period. The slope of the VO2-power output (W) relation (ΔVO2/ΔW) and DE were calculated in each subject at moderate to high intensities (above the ventilatory threshold—that is, from 50–60% to 100% VO2max). Results: The mean (SEM) values for ΔVO2/ΔW and DE had significantly decreased and increased respectively after the six week ES programme (p<0.05; 9.8 (0.2) v 8.6 (0.5) ml O2/W/min respectively and 27.7 (0.9) v 31.5 (1.4)% respectively). Conclusions: ES could be used as a supplementary tool to improve two of the main determinants of endurance capacity, namely VO2 kinetics and work efficiency. PMID:12663356

  20. VO2max trainability and high intensity interval training in humans: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Andrew P Bacon

    Full Text Available Endurance exercise training studies frequently show modest changes in VO2max with training and very limited responses in some subjects. By contrast, studies using interval training (IT or combined IT and continuous training (CT have reported mean increases in VO2max of up to ~1.0 L · min(-1. This raises questions about the role of exercise intensity and the trainability of VO2max. To address this topic we analyzed IT and IT/CT studies published in English from 1965-2012. Inclusion criteria were: 1≥ 3 healthy sedentary/recreationally active humans <45 yrs old, 2 training duration 6-13 weeks, 3 ≥ 3 days/week, 4 ≥ 10 minutes of high intensity work, 5 ≥ 1:1 work/rest ratio, and 6 results reported as mean ± SD or SE, ranges of change, or individual data. Due to heterogeneity (I(2 value of 70, statistical synthesis of the data used a random effects model. The summary statistic of interest was the change in VO2max. A total of 334 subjects (120 women from 37 studies were identified. Participants were grouped into 40 distinct training groups, so the unit of analysis was 40 rather than 37. An increase in VO2max of 0.51 L · min(-1 (95% CI: 0.43 to 0.60 L · min(-1 was observed. A subset of 9 studies, with 72 subjects, that featured longer intervals showed even larger (~0.8-0.9 L · min(-1 changes in VO2max with evidence of a marked response in all subjects. These results suggest that ideas about trainability and VO2max should be further evaluated with standardized IT or IT/CT training programs.

  1. Predicting VO2peak from Submaximal- and Peak Exercise Models: The HUNT 3 Fitness Study, Norway.

    Directory of Open Access Journals (Sweden)

    Henrik Loe

    Full Text Available Peak oxygen uptake (VO2peak is seldom assessed in health care settings although being inversely linked to cardiovascular risk and all-cause mortality. The aim of this study was to develop VO2peak prediction models for men and women based on directly measured VO2peak from a large healthy population.VO2peak prediction models based on submaximal- and peak performance treadmill work were derived from multiple regression analysis. 4637 healthy men and women aged 20-90 years were included. Data splitting was used to generate validation and cross-validation samples.The accuracy for the peak performance models were 10.5% (SEE = 4.63 mL⋅kg(-1⋅min(-1 and 11.5% (SEE = 4.11 mL⋅kg(-1⋅min(-1 for men and women, respectively, with 75% and 72% of the variance explained. For the submaximal performance models accuracy were 14.1% (SEE = 6.24 mL⋅kg(-1⋅min(-1 and 14.4% (SEE = 5.17 mL⋅kg(-1⋅min(-1 for men and women, respectively, with 55% and 56% of the variance explained. The validation and cross-validation samples displayed SEE and variance explained in agreement with the total sample. Cross-classification between measured and predicted VO2peak accurately classified 91% of the participants within the correct or nearest quintile of measured VO2peak.Judicious use of the exercise prediction models presented in this study offers valuable information in providing a fairly accurate assessment of VO2peak, which may be beneficial for risk stratification in health care settings.

  2. Photocatalytic Mineralization of Organic Acids over Visible-Light-Driven Au/BiVO4 Photocatalyst

    Directory of Open Access Journals (Sweden)

    Kanlaya Pingmuang

    2013-01-01

    Full Text Available Au/BiVO4 visible-light-driven photocatalysts were synthesized by coprecipitation method in the presence of sodium dodecyl benzene sulfonate (SDBS as a dispersant. Physical characterization of the obtained materials was carried out by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDX, UV-Vis diffuse reflectance spectroscopy (DRS and Brunauer, and Emmett and Teller (BET specific surface area measurement. Photocatalytic performances of the as-prepared Au/BiVO4 have also been evaluated via mineralizations of oxalic acid and malonic acid under visible light irradiation. XRD and SEM results indicated that Au/BiVO4 photocatalysts were of almost spherical particles with scheelite-monoclinic phase. Photocatalytic results showed that all Au/BiVO4 samples exhibited higher oxalic acid mineralization rate than that of pure BiVO4, probably due to a decrease of BiVO4 band gap energy and the presence of surface plasmon absorption upon loading BiVO4 with Au as evidenced from UV-Vis DRS results. The nominal Au loading amount of 0.25 mol% provided the highest pseudo-first-order rate constant of 0.0487 min−1 and 0.0082 min−1 for degradations of oxalic acid (C2 and malonic acid (C3, respectively. By considering structures of the two acids, lower pseudo-first-order rate constantly obtained in the case of malonic acid degradation was likely due to an increased complexity of the degradation mechanism of the longer chain acid.

  3. Plasma volume expansion does not increase maximal cardiac output or VO2 max in lowlanders acclimatized to altitude

    DEFF Research Database (Denmark)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert Christopher

    2004-01-01

    liter of 6% dextran 70 (BV = 6.32 +/- 0.34 liters). PV expansion had no effect on Qmax, maximal O2 consumption (VO2), and exercise capacity. Despite maximal systemic O2 transport being reduced 19% due to hemodilution after PV expansion, whole body VO2 was maintained by greater systemic O2 extraction (P...... VO2 during exercise regardless of PV. Pulmonary ventilation, gas exchange, and acid-base balance were essentially unaffected by PV expansion. Sea...

  4. A cost-effective method to fabricate VO{sub 2} (M) nanoparticles and films with excellent thermochromic properties

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hua [CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiao, Xiudi, E-mail: xiaoxd@ms.giec.ac.cn [CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Lu, Xuanming [CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chai, Guanqi; Sun, Yaoming; Zhan, Yongjun; Xu, Gang [CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2015-07-05

    Highlights: • Via solvent–thermal and pyrolysis method, VO{sub 2} (M) powder was synthesized in air. • Aiding by grinding, VO{sub 2} (M) nanoparticles with the size of 22 nm were obtained. • The VO{sub 2} films show great thermochromic properties with T{sub lum} = 62.1% and ΔT{sub sol} = 12.4%. • The haze is down to 1.9%, which is superior with films prepared by other methods. - Abstract: In this paper, high crystallinity and pure phase VO{sub 2} (M) powder is synthesized by a novel and facile method. Aiding by additional manual grinding and etching process, 22 nm high-quality VO{sub 2} (M) nanoparticles can be obtained. The structure and properties of the VO{sub 2} (M) particles were characterized by X-ray diffraction analysis, transmission electron microscopy, differential scanning calorimetry and UV–vis–NIR spectrophotometer. After mixing VO{sub 2} (M) nanoparticles with transparent polymer, thin films prepared by grinded VO{sub 2} nanoparticles show excellent thermochromic properties. The solar modulation ability is up to 12.4% with luminous transmittance of 62.7%. Moreover, The haze of films prepared by grinded VO{sub 2} (M) nanoparticles is down to 1.9%, which is far less than that of films prepared by original VO{sub 2} (Haze = 8.5%) and etched VO{sub 2} particles (Haze = 4.6%). Dramatical improvement of thermochromic property and definition indicate that it is a promising method to prepare large-scale VO{sub 2} nanoparticles and cost-effective smart window.

  5. Método basado en teledetección para estimar la emisión de gases efecto invernadero por quema de biomasa A remote sensing method to estimate greenhouse gas emissions from biomass burning

    Directory of Open Access Journals (Sweden)

    Jesús Adolfo Anaya Acevedo

    2011-01-01

    Full Text Available La quema de biomasa es una fuente importante de gases efecto invernadero en países en vías de desarrollo. En Colombia, el cambio de uso del suelo, la silvicultura y el sector agropecuario superan el 50% de las emisiones totales de efecto invernadero. El fuego se utiliza con frecuencia como un mecanismo para cambiar el uso del suelo. Los Llanos orientales y la Amazonía colombiana están sometidos todos los años a la quema de biomasa, especialmente entre enero y marzo. Los estudios en la distribución espacial y temporal de las emisiones son importantes de cara a los informes en el ámbito nacional. Este artículo de revisión describe el método para hacer estas estimaciones utilizando teledetección y algunos de los resultados disponibles para Colombia.Biomass burning is a major source of greenhouse gas emissions in developing countries. In Colombia, land use change, forestry and agriculture are responsible for more than 50% of the total greenhouse gas emissions. Fire is commonly used as a mechanism for land use change. In Colombia the Llanos Orientales and the Amazonia are subject to biomass burning every year during the dry season, especially from January to March. Studies of the spatial and temporal distribution of emissions are required for emissions report at a national level. The goal of this state of the art article is to describe a method to estimate emissions with a remote sensing approach and to present some of the variables already measured in Colombia.

  6. Evaluación de dos métodos para la estimación de biomasa arbórea a través de datos Landsat TM en Jusnajab La Laguna, Chiapas, México: estudio de caso

    Directory of Open Access Journals (Sweden)

    Jorge Escandón Calderón

    1999-01-01

    Full Text Available Se evaluaron dos métodos para estimar biomasa arbórea con apoyo en sensores remotos (LANDSAT TM. El primer método se realizó con base en una clasificación supervisada multiespectral con seis bandas Se utilizaron tipos de vegetación identificados a partir de la composición de biomasa de ¡os géneros dominantes y de la altura promedio estimada del dosel, habiéndose distinguido ocho clases de vegetación. Se obtuvo una biomasa total de 1 073 x 10 3t (902 x 10 3t a 1 220 x 10 3t En el segundo método se utilizaron índices diferenciados de vegetación (NDVI de las bandas TM4/TM3; TM4/TM5 y TM4/TM7. Se aplicó un modelo de regresión que relaciona la biomasa promedio con los valores digitales (VD de los NDVI. El modelo exponencial fue el de mejor ajuste para los tres NDVl con una p 0.01. Los valores de los NVDl fueron TM4/ TM3. R2=0 611, TM4/TM5. R2=0.671 y TM4/TM7: R2=0.676. La biomasa total estimada con cada NDVI fue de 1 164 x 10 3t (490 x 10 3t a 2 409 x 10 3t para TM4/TM3; de 515x10 3t (331 x 10 3 t a 757 x 1 0 3 t p a r a TM/TM5 y d e 726 x 1 0 3 t ( 3 9 8 x 1 0 3 t a 1 210 x 10 3t para TM4/TM7. El resultado de la biomasa total calculada por el método de clasificación multiespectral, comparado con los valores estimados por el método de ordenamiento exponencial, mostró mayor similitud con el valor máximo del NDVl que relaciona las bandas TM4/TM7 (de mayor ajuste estadístico y con el valor promedio del NDVl TM4/TM3 (de menor ajuste estadístico. Utilizando el NDVl TM4/TM5, todos los valores de biomasa resultaron más bajos. De este estudio se concluye que es posible asociar razonablemente la biomasa de vegetación arbolada de pino-encino y reservorios de carbono con los índices de vegetación. A través del uso de sensores remotos se podrían predecir cambios de biomasa en escalas temporales y espaciales.

  7. Enhanced photocatalytic performance of BiVO4 in aqueous AgNO3 solution under visible light irradiation

    Science.gov (United States)

    Huang, Chien-Kai; Wu, Tsunghsueh; Huang, Chang-Wei; Lai, Chi-Yung; Wu, Mei-Yao; Lin, Yang-Wei

    2017-03-01

    Monoclinic-phase bismuth vanadate (BiVO4) with a 2.468 eV band gap exhibited enhanced synergic photodegradation activity toward methylene blue (MB) when combined with silver ions (Ag+) in an aqueous solution under visible light irradiation. The mass ratio of AgNO3 to BiVO4 and the calcination temperature were discovered to considerably affect the degradation activity of BiVO4/Ag+. Superior photocatalytic performance was obtained when BiVO4 was mixed with 0.01%(w/v) AgNO3 solution, and complete degradation of MB was achieved after 25 min visible light irradiation, outperforming BiVO4 or AgNO3 solution alone. The enhanced photodegradation was investigated using systematic luminescence measurements, electrochemical impedance spectroscopy, and scavenger addition, after which a photocatalytic mechanism for MB degradation under visible light irradiation was identified that involved oxygen radicals and holes. This study also discovered the two dominating processes involved in enhancing the electron-hole separation efficiency and reducing their recombination rate, namely photoreduction of Ag+ and the formation of a BiVO4/Ag heterojunction. The synergic effect between BiVO4 and Ag+ was discovered to be unique. BiVO4/Ag+ was successfully used to degrade two other dyes and disinfect Escherichia Coli. A unique fluorescent technique using BiVO4 and a R6G solution to detect Ag+ ions in water was discovered.

  8. Effect of protocol on determination of velocity at VO2 max and on its time to exhaustion.

    Science.gov (United States)

    Billat, V L; Hill, D W; Pinoteau, J; Petit, B; Koralsztein, J P

    1996-01-01

    The velocity associated with the achievement of VO2 max during an incremental treadmill test (v VO2 max) has been reported to be an indicator of performance in middle distance running events. Previous study has shown the reproducibility of the time to exhaustion (time limit: tlim) at v VO2 max performed by well-trained males in the same condition at one week of interval (Billat et al., 1994b). It is essential in studies involving tlim at v VO2 max that the v VO2 max be precisely determined, or else the measured tlim will be meaningless. The purpose of this study was to examine the influence of the stage duration and velocity incrementation on the velocity at VO2 max and, consequently, on the two times to exhaustion (tlim) associated with the two v VO2 max generated by the two protocols. v VO2 max was determined in 15 trained male endurance athletes as the lowest speed at which VO2 max was attained in speed-incremented 0%-slope treadmill tests. For one test, increments were 1.0 km.h-1 and stages were 2 min in duration; for the other test, increments were 0.5 km.h-1 and stages were 1 min in duration. Results of paired means t-tests revealed no difference in v VO2 max obtained using the two protocols. v VO2 max was 20.7 +/- 1.0 km.h-1 with the 1.0 km.h-1 x 2 min protocol and 20.8 +/- 0.9 km.h-1 with the 0.5 km.h-1 x 1 min protocol. In addition, VO2, VCO2, VE, VE/VO2 and respiratory exchange ratio at the submaximal intensities that were common to both protocols (e.g., 17.0 km.h-1, 18.0 km.h-1, 19.0 km.h-1, 20.0 km.h-1) did not differ. Times to exhaustion at the two v VO2 max demonstrated a high degree of inter-individual variability (coefficients of variation were 35% and 45%) but did not differ (345 +/- 120 s versus 373 +/- 169 s). These results demonstrated that small changes in protocol have no significant impact on the value of v VO2 max and in consequence on tlim v VO2 max.

  9. 1D ZnO/BiVO4 heterojunction photoanodes for efficient photoelectrochemical water splitting.

    Science.gov (United States)

    Yan, Lu; Zhao, Wei; Liu, Zhifeng

    2016-07-28

    In this paper, a novel ZnO nanorods (NRs)/BiVO4 heterojunction has been successfully prepared as a photoanode for photoelectrochemical (PEC) water splitting. Firstly, ZnO NRs were synthesized by chemical bath deposition onto indium tin oxide (ITO) coated glass. Then BiVO4 was deposited by successive ionic layer adsorption and reaction (SILAR). The photocurrent density of ZnO NRs and the ZnO NRs/BiVO4 heterojunction photoanode was evaluated under light irradiation. And the value was up to 1.72 mA cm(-2) at 1.2 V vs. Ag/AgCl based on the ZnO NRs/BiVO4 photoanode in the electrolyte solution, which is higher than that of the pure ZnO NRs photoanode at the same potential. It is demonstrated that the presence of BiVO4 has played an important role in expanding the spectral response region and reducing the photogenerated charge recombination rate. This present work provides a simple synthesis route to construct a heterojunction which serves as a photoanode for PEC water splitting.

  10. VO 2+ ions in zinc lead borate glasses studied by EPR and optical absorption techniques

    Science.gov (United States)

    Prakash, P. Giri; Rao, J. Lakshmana

    2005-09-01

    Electron paramagnetic resonance (EPR) and optical absorption spectra of vanadyl ions in zinc lead borate (ZnO-PbO-B 2O 3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO 2+ ions. The values of spin-Hamiltonian parameters indicate that the VO 2+ ions in zinc lead borate glasses were present in octahedral sites with tetragonal compression and belong to C 4V symmetry. The spin-Hamiltonian parameters g and A are found to be independent of V 2O 5 content and temperature but changing with ZnO content. The decrease in Δ g∥/Δ g⊥ value with increase in ZnO content indicates that the symmetry around VO 2+ ions is more octahedral. The decrease in intensity of EPR signal above 10 mol% of V 2O 5 is attributed to a fall in the ratio of the number of V 4+ ions ( N4) to the number of V 5+ ions ( N5). The number of spins ( N) participating in resonance was calculated as a function of temperature for VO 2+ doped zinc lead borate glass sample and the activation energy was calculated. From the EPR data, the paramagnetic susceptibility was calculated at various temperatures and the Curie constant was evaluated from the 1/ χ- T graph. The optical absorption spectra show single absorption band due to VO 2+ ions in tetragonally distorted octahedral sites.

  11. Science with the Virtual Observatory: the AstroGrid VO Desktop

    CERN Document Server

    Tedds, Jonathan A

    2009-01-01

    We introduce a general range of science drivers for using the Virtual Observatory (VO) and identify some common aspects to these as well as the advantages of VO data access. We then illustrate the use of existing VO tools to tackle multi wavelength science problems. We demonstrate the ease of multi mission data access using the VOExplorer resource browser, as provided by AstroGrid (http://www.astrogrid.org) and show how to pass the various results into any VO enabled tool such as TopCat for catalogue correlation. VOExplorer offers a powerful data-centric visualisation for browsing and filtering the entire VO registry using an iTunes type interface. This allows the user to bookmark their own personalised lists of resources and to run tasks on the selected resources as desired. We introduce an example of how more advanced querying can be performed to access existing X-ray cluster of galaxies catalogues and then select extended only X-ray sources as candidate clusters of galaxies in the 2XMMi catalogue. Finally ...

  12. Effects of erythrocyte infusion on VO2max at high altitude

    DEFF Research Database (Denmark)

    Young, Jette Feveile; Sawka, M N; Muza, S R

    1996-01-01

    This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days...... of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control...... group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P

  13. VO{sub x} effectively doping CVD-graphene for transparent conductive films

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Qinghua; Shi, Liangjing [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zhang, Qinghong [State Key Laboratory of Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620 (China); Wang, Weiqi; Zheng, Huifeng [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Zhang, Yuzhi [The Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences,1295 Dingxi Road, Shanghai 200050 (China); Liu, Yangqiao, E-mail: yqliu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Sun, Jing, E-mail: jingsun@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2016-11-30

    Highlights: • Doping process operated easily. • Sheet resistance decreased efficiently after doping. • Sheet resistance of doped graphene is stable after exposed in the air. • Mechanism of doping process is studied. - Abstract: Chemical vapor deposition(CVD)-synthesized graphene is potentially an alternative for tin-doped indium oxide (ITO) transparent conductive films (TCFs), however its sheet resistance is still too high to meet many demands. Vanadium oxide has been widely applied as smart window materials, however, no study has been reported to use it as dopant to improve the conductivity of graphene TCFs. In this study, we firstly reported that VO{sub x} doping can effectively lower the sheet resistance of CVD-graphene films while keeping its good optical properties, whose transmittance is as high as 86–90%. The optimized VO{sub x}-doped graphene exhibits a sheet resistance as low as 176 Ω/□, which decreases by 56% compared to the undoped graphene films. The doping process is convenient, stable, economical and easy to operate. What is more, VO{sub x} can effectively increase the work function(WF) of the film, making it more appropriate for use in solar cells. The evolution of the VO{sub x} species annealed at different temperatures below 400 °C has been detailed studied for the first time, based on which the doping mechanism is proposed. The prepared VO{sub x} doped graphene is expected to be a promising candidate for transparent conductive film purposes.

  14. Preparation of BiVO4-Graphene Nanocomposites and Their Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Xuan Xu

    2014-01-01

    Full Text Available We prepared BiVO4-graphene nanocomposites by using a facile single-step method and characterized the material by x-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet-visible diffuse-reflection spectroscopy, and three-dimensional fluorescence spectroscopy. The results show that graphene oxide in the catalyst was thoroughly reduced. The BiVO4 is densely dispersed on the graphene sheets, which facilitates the transport of electrons photogenerated in BiVO4, thereby leading to an efficient separation of photogenerated carriers in the coupled graphene-nanocomposite system. For degradation of rhodamine B dye under visible-light irradiation, the photocatalytic activity of the synthesized nanocomposites was over ∼20% faster than for pure BiVO4 catalyst. To study the contribution of electrons and holes in the degradation reaction, silver nitrate and potassium sodium tartrate were added to the BiVO4-graphene photocatalytic reaction system as electron-trapping agent and hole-trapping agent, respectively. The results show that holes play the main role in the degradation of rhodamine B.

  15. PROPER CONDITIONS OF MESHING FOR Hy-Vo SILENT CHAIN AND SPROCKET

    Institute of Scientific and Technical Information of China (English)

    MENG Fanzhong; LI Chun; CHENG Yabing

    2007-01-01

    Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmission of the silent chain with more efficiency and less noise. Based on the study of the meshing theory of the Hy-Vo silent chain with the sprocket and the roll cutting machining principle of the sprocket with the hob, the proper conditions of the meshing for the Hy-Vo silent chain and the sprocket are put forward with the variable pitch characteristic of the Hy-Vo silent chain taken into consideration, and the proper meshing design method on the condition that the value of the link tooth pressure angle is unequal to the value of the sprocket tooth pressure angle is studied. Experiments show that this new design method is feasible. In addition, the design of the pitch, the sprocket tooth pressure angle and the fillet radius of the sprocket addendum circle arc studied. It is crucial for guiding the design of the hob which cuts the Hy-Vo silent chain sprocket.

  16. Steady exercise removes VO(2max) difference between mitochondrial genomic variants.

    Science.gov (United States)

    Marcuello, Ana; Martínez-Redondo, Diana; Dahmani, Yahya; Terreros, José L; Aragonés, Teresa; Casajús, José A; Echavarri, José M; Quílez, Julia; Montoya, Julio; López-Pérez, Manuel J; Díez-Sánchez, Carmen

    2009-09-01

    It has been clearly established that mitochondrial variants, among other potential factors, influence on VO(2max). With this study we sought to determine whether this genetic predisposition could be modified by steady exercise. Mitochondrial genetic variants were determined in 70 healthy controls (CON) and in 77 athletes who trained regularly (50 cyclists, aerobic training (AER), and 27 runners of 400m, anaerobic training (NoAER)). All of them were male Spanish Caucasian individuals. A maximum graded exercise test (GXT) in cycle-ergometer was performed to determine VO(2max) (mL kg(-1)min(-1)). Our results confirmed that, in CON, VO(2max) (P=0.007) was higher in Non-J than J individuals. Furthermore, we found that AER and NoAER showed, as it could be expected, higher VO(2max) than CON, but not differences between mitochondrial variants have been found. According with these findings, the influence of mitochondrial DNA (mtDNA) variants on VO(2max) has been confirmed, and a new conclusion has arisen: the steady exercise is able to remove this influence. The interest of these promising findings in muscular performance should be further explored, in particular, the understanding of potential applications in sport training and in muscle pathological syndromes.

  17. Photocatalytic perfermance of sandwich-like BiVO4 sheets by microwave assisted synthesis

    Science.gov (United States)

    Liu, Suqin; Tang, Huiling; Zhou, Huan; Dai, Gaopeng; Wang, Wanqiang

    2017-01-01

    Sandwich-like BiVO4 sheets were successfully synthesized in an aqueous solution containing bismuth nitrate, ammonium metavanadate and polyethylene glycol with a molecular weight of 10,000 (PEG-10000) using a facile microwave-assisted method. The as-prepared samples were characterized by scanning electron microscopy, N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy. The results show that the presence of PEG-10000 plays a critical role in the formation of BiVO4 sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO4 sheets exhibit a high activity for the degradation of methyl orange under visible light irradiation (λ ≥ 420 nm). The enhancement of photocatalytic activity of sandwich-like BiVO4 sheets can be attributed to its large surface area over the irregular BiVO4 particles.

  18. Application Oriented Flow Routing Algorithm for VoIP Overlay Networks

    Science.gov (United States)

    Wipusitwarakun, Komwut; Chimmanee, Sanon

    Overlay networks which are dynamically created over underlying IP networks are becoming widely used for delivering multimedia contents since they can provide several additional user-definable services. Multiple overlay paths between a source-destination overlay node pair are designed to improve service robustness against failures and bandwidth fluctuation of the underlying networks. Multimedia traffic can be distributed over those multiple paths in order to maximize paths' utilization and to increase application throughputs. Most of flow-based routing algorithms consider only common metrics such as paths' bandwidth or delay, which may be effective for data applications but not for real-time applications such as Voice over IP (VoIP), in which different levels of such performance metrics may give the same level of the performance experienced by end users. This paper focuses on such VoIP overlay networks and proposes a novel alternative path based flow routing algorithm using an application-specific traffic metric, i.e. “VoIP Path Capacity (VPCap), ” to calculate the maximum number of QoS satisfied VoIP flows which may be distributed over each available overlay path at a moment. The simulation results proved that more QoS-satisfied VoIP sessions can be established over the same multiple overlay paths, comparing to traditional approaches.

  19. Transmission of reactive pulsed laser deposited VO2 films in the THz domain

    Science.gov (United States)

    Émond, Nicolas; Hendaoui, Ali; Ibrahim, Akram; Al-Naib, Ibraheem; Ozaki, Tsuneyuki; Chaker, Mohamed

    2016-08-01

    This work reports on the characteristics of the insulator-to-metal transition (IMT) of reactive pulsed laser deposited vanadium dioxide (VO2) films in the terahertz (THz) frequency range, namely the transition temperature TIMT, the amplitude contrast of the THz transmission over the IMT ΔA, the transition sharpness ΔT and the hysteresis width ΔH. XRD analysis shows the sole formation of VO2 monoclinic structure with an enhancement of (011) preferential orientation when varying the O2 pressure (PO2) during the deposition process from 2 to 25 mTorr. THz transmission measurements as a function of temperature reveal that VO2 films obtained at low PO2 exhibit low TIMT, large ΔA, and narrow ΔH. Increasing PO2 results in VO2 films with higher TIMT, smaller ΔA, broader ΔH and asymmetric hysteresis loop. The good control of the VO2 IMT features in the THz domain could be further exploited for the development of advanced smart devices, such as ultrafast switches, modulators, memories and sensors.

  20. Thermochromic VO{sub 2} on Zinnwaldite Mica by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mathevula, L., E-mail: langu@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Ngom, B.D.; Kotsedi, L.; Sechogela, P. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Doyle, T.B. [Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa); School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4001 (South Africa); Ghouti, M.; Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Western Cape (South Africa)

    2014-09-30

    Highlights: • Vanadium dioxide was successfully synthesized by pulsed laser deposition method on mica. • The morphology evolution within the samples is characterized by a change from isolated and less-percolating (0 1 1) VO{sub 2} crystallites to a percolating granular configuration. • Without any post annealing, the films exhibit a textured nature with a VO{sub 2} (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio R{sub S}/R{sub M} through the SMT at T ≈ 68 °C of the order of 10{sup 4} and a narrow ∼7 °C hysteresis. - Abstract: VO{sub 2} thin films have been deposited by pulsed laser deposition on Zinnwaldite Mica substrates. The crystal structure, chemical composition, morphology were determined and the semiconductor/metal transition (SMT) properties of the deposited films were investigated. Without any post annealing, the films exhibit a textured nature with a VO{sub 2} (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio R{sub S}/R{sub M} through the SMT at T ≈ 68 °C of the order of 10{sup 4} and a narrow ∼7 °C hysteresis. In addition, the growth of the VO{sub 2} crystallites seem to be governed likely by a Volmer-Weber or Stranski-Krastanov mechanisms and certainly not a Frank-van Der Merwe process.

  1. Laminarin-induced apoptosis in human colon cancer LoVo cells.

    Science.gov (United States)

    Ji, Chen-Feng; Ji, Yu-Bin

    2014-05-01

    A number of scientific studies have revealed that laminarin has antitumor effects. Therefore, the aim of the present study was to investigate the apoptosis of LoVo cells and the underlying mechanisms induced by laminarin. LoVo cells were treated with various concentrations of laminarin and fluorescence-inverted microscopy was used to observe the morphology of LoVo cells treated with laminarin. In addition, western blotting was performed to analyze the expression levels of death receptor (DR)4, DR5, TNF-related apoptosis-inducing ligand (TRAIL), Fas-associated protein with death domain (FADD), caspase-8, caspase-3, Bid and tBid. Flow cytometry was conducted to analyze the expressions of Bcl-2 and Bax, and spectrophotometry was performed to quantify the activity of caspases-8, -3, -6 and -7. Following the treatment of LoVo cells with laminarin for 24 h, the expression levels of DR4, DR5, TRAIL, FADD, Bid, tBid and Bax were observed to be upregulated, whereas the expression levels of pro-caspase-8, pro-caspase-3 and Bcl-2 were downregulated. In addition, the activities of casapse-8, -3, -6 and -7 were observed to increase, which was a significant difference when compared with those of the control group. Therefore, laminarin is considered to induce the apoptosis of LoVo cells, which may occur via a DR pathway, suggesting that laminarin may be a potent agent for cancer treatment.

  2. ScVO4 under non-hydrostatic compression: a new metastable polymorph

    Science.gov (United States)

    Garg, Alka B.; Errandonea, D.; Rodríguez-Hernández, P.; Muñoz, A.

    2017-02-01

    The high-pressure (HP) behaviour of scandium vanadate (ScVO4) is investigated under non-hydrostatic compression. The compound is studied by means of synchrotron-based powder x-ray diffraction (XRD) and optical-absorption techniques. The occurrence of a non-reversible phase transition is detected. The transition is from the zircon structure to the fergusonite-type structure and takes place around 6 GPa with nearly 10% volume discontinuity. XRD measurements on the pressure cycled sample confirm for the first time that the fergusonite-type ScVO4 can be recovered as the metastable phase at ambient conditions. Raman spectroscopic measurements verify the metastable phase to be of a fergusonite-type phase. Theoretical calculations also corroborate the experimental findings. The fergusonite phase is found to be stiffer than the ambient-pressure zircon phase, as indicated by the observed experimental and theoretical bulk moduli. The optical properties and lattice-dynamics calculation of the fergusonite ScVO4 are discussed. At ambient pressure the band gap of the zircon (fergusonite)-type ScVO4 is 2.75 eV (2.3 eV). This fact suggests that the novel metastable polymorph of ScVO4 can have applications in green technologies; for instance, it can be used as photocatalytic material for hydrogen production by water splitting.

  3. Supercapacitors based on two dimensional VO2 nanosheet electrodes in organic gel electrolyte

    KAUST Repository

    Rakhi, R.B.

    2016-10-16

    VO2 is a low band-gap semiconductor with relatively high conductivity among transition metal oxides, which makes it an interesting material for supercapacitor electrode applications. The performance of VO2 as supercapacitor electrode in organic electrolytes has never been reported before. Herein, two-dimensional nanosheets of VO2 are prepared by the simultaneous solution reduction and exfoliation from bulk V2O5 powder by hydrothermal method. A specific capacitance of 405 Fg−1 is achieved for VO2 based supercapacitor in an organic electrolyte, in three electrode configuration. The symmetric capacitor based on VO2 nanosheet electrodes and the liquid organic electrolyte exhibits an energy density of 46 Wh kg−1 at a power density of 1.4 kW kg−1 at a constant current density of 1 Ag−1. Furthermore, flexible solid-state supercapacitors are fabricated using same electrode material and Alumina-silica based gel electrolyte. The solid-state device delivers a specific capacitance of 145 Fg−1 and a device capacitance of 36 Fg−1 at a discharge current density of 1 Ag−1. Series combination of three solid state capacitors is capable of lighting up a red LED for more than 1 minute.

  4. Synthesis of BiVO4 nanosheets-graphene composites toward improved visible light photoactivity

    Institute of Scientific and Technical Information of China (English)

    Qianqian Yu; Zi-Rong Tang; Yi-Jun Xua

    2014-01-01

    Two-dimensional (2-D) BiVO4 nanosheets-graphene (GR) composites with different weight addition ratios of GR have been prepared via a facile wet chemistry process. X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectra (XPS), UV-vis diffuse reflectance spectra (DRS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption, transient photocurrent response and photoluminescence (PL) spectra were employed to determine the properties of the samples. It is found that BiVO4 nanosheets could pave well on the surface of graphene sheets. BiVO4 nanosheets-GR composites with a proper addition amount of GR exhibited higher photocatalytic activity than bare BiVO4 nanosheets toward liquid-phase degradation of rhodamine B (RhB) and methyl orange (MO) under visible light irradiation. The enhancement of photocatalytic activities of BiVO4 nanosheets-GR composites can be attributed to the effective separation of photoexcited electron-hole pairs. This work not only provides a simple strategy for fabricating specific 2-D semiconductor-2-D GR composites, but also opens a new window of such 2-D semiconductor-2-D GR composites as visible light photocatalysts toward an improved visible light photoactivity in purifying polluted water resources.

  5. Concentration Dependence of VO2+ Crossover of Nafion for Vanadium Redox Flow Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, Jamie [University of Tennessee, Knoxville (UTK); Jones, Amanda [University of Tennessee, Knoxville (UTK); Zawodzinski, Thomas A [ORNL

    2013-01-01

    The VO2+ crossover, or permeability, through Nafion in a vanadium redox flow battery (VRFB) was monitored as a function of sulfuric acid concentration and VO2+ concentration. A vanadium rich solution was flowed on one side of the membrane through a flow field while symmetrically on the other side a blank or vanadium deficit solution was flowed. The blank solution was flowed through an electron paramagnetic resonance (EPR) cavity and the VO2+ concentration was determined from the intensity of the EPR signal. Concentration values were fit using a solution of Fick s law that allows for the effect of concentration change on the vanadium rich side. The fits resulted in permeability values of VO2+ ions across the membrane. Viscosity measurements of many VO2+ and H2SO4 solutions were made at 30 60 C. These viscosity values were then used to determine the effect of the viscosity of the flowing solution on the permeability of the ion. 2013 The Electrochemical Society. [DOI: 10.1149/2.004306jes] All rights reserved.

  6. The influence of charge transfers effects in monazite-type LaVO{sub 4} and perovskite-type LaVO{sub 3} prepared by sol-gel acrylamide polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Pérez, G., E-mail: guillermo.herrera@cimav.edu.mx [CONACYT Research Fellow. Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Jiménez-Mier, J. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, 04510 Mexico D. F (Mexico); Yang, W.-L. [The Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Reyes-Rojas, A.; Fuentes-Cobas, L.E. [Department of Physics of Materials Department. Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico)

    2016-08-15

    Highlights: • We elucidate the electronic structure through the vanadium L{sub 2,3} edge in LaVO{sub 4} by XAS. • The interpretation of XAS spectrum was performed by the multiplet calculation. • Our results suggest that LaVO{sub 4} can be considered in the charge transfer regime. - Abstract: Core-hole spectroscopy such as X-ray absorption spectroscopy (XAS) is useful to determine the electronic structure of strongly correlated and strongly hybridized compounds such as vanadates. Monazite-type LaVO{sub 4} and perovskite-type LaVO{sub 3} are good candidates to elucidate the electronic structure through the vanadium L{sub 2,3} edge. LaVO{sub 4} was prepared by sol-gel acrylamide polymerization and solid-state reaction. LaVO{sub 3} was obtained by reduction of LaVO{sub 4} using Zr as gatherer. Monoclinic crystal phase for LaVO{sub 4} and orthorhombic crystal phase for LaVO{sub 3} were confirmed by the Rietveld refinement of X-ray diffraction patterns. XAS comparison between Vanadium L{sub 2,3} edge confirms the presence of V{sup 5+} for the monazite and V{sup 3+} for the orthorhombic perovskite. Multiplet calculations including crystal field and charge transfer effects (CTM) were performed in order to elucidate the tetragonal (D{sub 4h} symmetry) parameters Dq, Ds and Dt, the charge transfer energy Δ, and d-d Coulomb repulsion energy U parameters. CTM confirms for LaVO{sub 3} the strong V 3d–O 2p hybridization with a significant contribution of covalent character due to the delocalization of 3d electrons. For LaVO{sub 4} this work suggest the reclassification of this band insulator as charge transfer insulator that shows a significant contribution of ionic character.

  7. Electrical and optical properties of VO2 thin films grown on various sapphire substrates by using RF sputtering deposition

    Science.gov (United States)

    Jung, Dae Ho; So, Hyeon Seob; Ko, Kun Hee; Park, Jun Woo; Lee, Hosun; Nguyen, Trang Thi Thu; Yoon, Seokhyun

    2016-12-01

    VO2 thin films were grown on a-, c-, m-, and r-plane sapphire and SiO2/Si substrates under identical conditions by using RF sputtering deposition from a VO2 target. The structural and the morphological properties of all VO2 films were investigated. The grain sizes of the VO2 films varied between 268 nm and 355 nm depending on the substrate's orientation. The electrical and the optical properties of all VO2 thin films were examined in detail. The metal-insulator transition temperature (TMI) varied with the substrate's orientation. The (200)/(bar 211 )-oriented VO2 films on the a-plane sapphire showed the lowest TMI of about 329.3 K (56.3 °C) while the (020)/(002)-VO2 films on the c-plane sapphire displayed the highest TMI of about 339.6 K (66.6 °C). The VO2 films showed reversible changes in the resistivity as large as 1.19 × 105 and a hysteresis of 2 K upon traversing the transition temperature. The variations observed in the TMI with respect to the substrate's orientation were due to changes in the lattice strain and the grain size distribution. Raman spectroscopy showed that metal (rutile) - insulator (monoclinic) transitions occurred via the M2 phase for VO2 films on the c-plane substrate rather than the direct M1 to rutile transition. The shifts in the phonon frequencies of the VO2 film grown on various sapphire substrates were explained in terms of the strain along the V-V atomic bond direction (cR). Our work shows a possible correlation between the transition parameters ( e.g., TMI, sharpness, and hysteresis width) and the width ( σ) of the grain size distribution. It also shows a possible correlation between the TMI and the resistivities at the insulating and the metallic phases for VO2 films grown on various sapphire substrates.

  8. Controlled synthesis of T-shaped BiVO{sub 4} and enhanced visible light responsive photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shuying; Yu, Chongfei; Li, Yukun [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China); Li, Yihui [School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Sun, Jianhui, E-mail: sunjh@htu.cn [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China); Geng, Xiaofei [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China)

    2014-03-15

    A novel T-shaped BiVO{sub 4} microcrystal photocatalyst was successfully synthesized by the hydrothermal method with the aid of a structure-directing surfactant SDBS in the present study. Having received well characterization with the aid of various techniques and the results showed that the SDBS greatly changed the microstructure of BiVO{sub 4}, which had a unique T shape and belonged to the monoclinic family. The fast exchange dynamics between the surfactants bound to the Bi{sup 3+} seed surface and the free VO{sub 3}{sup −} in the solution significantly increase the rate of heterogeneous nucleation. In addition, the photocatalytic activity of the prepared T-shaped BiVO{sub 4} was evaluated by the degradation of Methylene Blue solution under visible light irradiation, 17% and 47% higher decolorization rates than the commercial P25 and BiVO{sub 4} synthesized without SDBS, respectively. Meanwhile, it has been found that the degradation kinetics of MB fitted the pseudo-first-order kinetics and the T-shaped BiVO{sub 4} also displayed high photocatalytic performance for metronidazole degradation. -- Graphical abstract: H{sub 2}O{sub 2} molecules function as electron trapping reagent to react with e{sup −} to enhance the photocatalytic degradation efficiency of MB in the BiVO{sub 4}/H{sub 2}O{sub 2} system under visible light irradiation. Highlights: • T-shaped BiVO{sub 4} was synthesized using SDBS as a structure-directing surfactant. • SDBS greatly changed the microstructure of BiVO{sub 4}. • The T-shaped BiVO{sub 4} had a better visible-light photocatalytic activity. • Degradation kinetics of MB by BiVO{sub 4} fitted the pseudo-first-order kinetics.

  9. RGO/InVO{sub 4} hollowed-out nanofibers: Electrospinning synthesis and its application in photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Dong [Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); College of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China); Zhang, Yanxiang [College of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Gao, Mengchun, E-mail: mengchungao@outlook.com [Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); Xin, Yanjun; Wu, Juan [College of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China); Bao, Nan [College of Environmental Science and Engineering, Shandong University, Jinan 250100 (China)

    2015-10-30

    Graphical abstract: - Highlights: • RGO/InVO{sub 4} hollow-out nanofibers were obtained by electrospinning method. • The properties of InVO{sub 4} hollow-out nanofibers were deeply influenced by RGO. • RGO could reduce recombination of e{sup −}–h{sup +} pairs to improve photocatalytic activity. • Photo-induced h{sup +} and e{sup −} are the two main reactive species for RhB degradation. - Abstract: A composite of reduced graphene oxide (RGO) and InVO{sub 4} nanofiber was successfully synthesized by an electrospinning technique. The as-collected fibers were calcined at 420 °C in air and then calcined at 550 °C in nitrogen gas to remove polyvinyl pyrrolidone (PVP), which could enable InVO{sub 4} to crystallize and protect the RGO from oxidation. The InVO{sub 4} in the composite illustrated a hollowed-out fibrous morphology and orthorhombic phase, and RGO nanosheets were nested in the InVO{sub 4} nanofibers. The hybrid RGO could produce more hydroxyl groups and a higher oxygen vacancy density on the surface of RGO/InVO{sub 4} composite. Compared with pure InVO{sub 4}, the light absorption range of the as-prepared RGO/InVO{sub 4} composite was expanded. In Rh B degradation, the RGO/InVO{sub 4} hybrid nanofibers displayed a higher photocatalytic activity than pure InVO{sub 4} nanofibers. The enhanced photocatalytic activity might be ascribed to the role of RGO as an electron transporter and acceptor in the composite, which could effectively inhibit the charge recombination and facilitate the charge transfer. The exported electron could attack an O{sub 2} molecule to facilitate the generation of • O{sub 2}{sup −} and • OH for the photodegradation process of Rh B.

  10. Hongos micorrízicos arbusculares como agentes mitigadores del estrés salino por NaCl en plántulas de albahaca

    Directory of Open Access Journals (Sweden)

    Y. Milagro Agüero -Fernández

    2016-01-01

    Full Text Available En la naturaleza las plantas se encuentran expuestas a diversas condiciones de estrés que retardan su desarrollo y disminuyen su rendimiento. Uno de los problemas agrícolas más exte ndidos es la acumulación de sales en la superficie del suelo o la salinización del agua para riego . El objetivo del estudio fue eva luar un consorcio de hongos micorrízicos arbusculares (HMA de las especies Funneliformis mosseae y Claroideoglomus etunicatum inoculadas a la cubierta de la semillas como posibl es mitigadores del estrés por NaCl en plántulas de variedades de albahaca en la etapa de emergencia. Se utilizó un diseño completamente al azar con arreglo factorial. El factor 1 fueron tres variedades de albahaca (Nuffar, Genovese y Napoletano, el factor 2 fueron tres niveles de estrés salino (0, 50 y 100 mM de NaCl y el factor 3, los hongos micorrí zicos arbusculares ( 0 -control - y 1 g del inoculo con cuatro repeticiones de 30 semillas cada una. Se evaluó la composición química del sustrato y del inócul o utilizado s, la tasa y porcentaje de emergencia, altura de las plántula s, longitud de raíz, biomasa fresca de parte aérea y de raíz y porce ntaje de colonización. Los resultados mostraron que tanto el sustrato como el inóculo utilizados fueron adecuados para el desarrollo de las especies de HMA evaluadas y para la especie vegetal en estudio. Ninguna de las raíces de las plántulas de las variedades en estudio mostró presencia de vesículas, arbúsculos y/o hifas cenocíticas . T odas las variables presentaron val ores superiores en aquellas plántulas cuyas semillas se inocularon con HMA. Las variedades mostraron diferencias para las variables tasa y porcentaje de emergencia, altura de plántula , longitud de raíz y biomasa fresca de parte aérea, siendo N apoletano superior, mientras que Genovese mostr ó lo contrario. La s variables tasa y porcentaje de emergencia, altura de plántula, longitud de raíz y biomasa fresca de ra

  11. AgVO3 nanorods: Synthesis, characterization and visible light photocatalytic activity

    Science.gov (United States)

    Sivakumar, V.; Suresh, R.; Giribabu, K.; Narayanan, V.

    2015-01-01

    Large scale and high purity silver vanadate (AgVO3) nanorods were synthesized by thermal decomposition method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, Ultraviolet-Visible (DRS-UV-Visible) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize the structure, light absorption capacity and morphology of the as-synthesized sample. The photocatalytic activity of AgVO3 nanorods was examined by degradation of methylene blue (MB) as a model organic pollutant. The degradation efficiency is 85.02% in the 120 min visible light illumination. Further, the AgVO3 nanorods were used as a photocatalyst for industrial effluent. 95.4% degradation efficiency was obtained within the visible light irradiation of 120 min. The possible photocatalytic mechanism has also been proposed.

  12. Security Analysis System to Detect Threats on a SIP VoIP Infrasctructure Elements

    Directory of Open Access Journals (Sweden)

    Jiri Vychodil

    2011-01-01

    Full Text Available SIP PBX is definitely the alpha and omega of any IP telephony infrastructure and frequently also provides other services than those related to VoIP traffic. These exchanges are, however, very often the target of attacks by external actors. The article describes a system that was developed on VSB-TU Ostrava as a testing tool to verify if the target VoIP PBX is adequately secured and protected against any real threats. The system tests the SIP element for several usually occurring attacks and it compiles evaluation of its overall security on the basis of successfully or unsuccessfully penetrations. The article describes the applications and algorithms that are used by system and the conclusion consists recommendations and guidelines to ensure effective protection against VoIP PBX threats. The system is designed as an open-source web application, thus allowing independent access and is fully extensible to other test modules.

  13. Self-assembly of highly crystalline spherical BiVO 4 in aqueous solutions

    Science.gov (United States)

    Yang, Tao; Xia, Dingguo

    2009-10-01

    Spherical bismuth vanadate particles are self-assembled from aqueous Bi(NO 3) 3 and NH 4VO 3 solutions by adjusting pH and tuning the amount of surfactant sodium dodecyl sulfate (SDS) via facile hydrothermal method. The BiVO 4 samples were characterized by X-ray diffraction (XRD) and the peaks suited well with the pure phase monoclinic scheelite BiVO 4. Field emission scanning electron microscopy (SEM) showed the average size of the spherical particles was 5 μm and the assembling stages in the hydrothermal synthesis process were recorded. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) revealed the nanoparticles were single crystal. FT-IR spectroscopy test results demonstrated there was no SDS left in the samples. The mechanism of the self-assembling has also been proposed.

  14. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode.

    Science.gov (United States)

    Zhou, Bin; Qu, Jiuhui; Zhao, Xu; Liu, Huijuan

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating. After annealation at 400, 500, and 600 degrees C, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry. The BiVO4 particles on the ITO glass surface had a monoclinic structure. The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV. In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichlorophenol and Bisphenol A degradation under visible light irradiation (lambda > 420 nm). Over 90% of the two organic pollutants were removed in 5 hr. A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  15. Effects of simulated weightlessness and sympathectomy on maximum VO2 of male rats

    Science.gov (United States)

    Woodman, C. R.; Stump, C. S.; Beaulieu, S. M.; Rahman, Z.; Sebastian, L. A.

    1989-01-01

    The effects of simulated weightlessness (hind-limb suspension) and chemical sympathectomy (by repeated injections with guanethidine sulfate) on the maximum oxygen consumption (VO2 max) of female rats were investigated in rats assigned for 14 days to one of three groups: a head-down hind-limb suspension, a horizontal suspension with hind limbs weight bearing, or the caged control. The VO2 max values were assessed by having rats run on a treadmill enclosed in an airtight chamber. The hind-limb-suspended sympathectomized rats were found to exhibit shorter run times and lower mechanical efficiencies, compared to their presuspension values or the values from saline-injected suspended controls. On the other hand, the suspended sympathectomized rats did not demonstrate a decrease in the VO2 max values that was observed in saline-injected controls.

  16. Field Effect and Strongly Localized Carriers in the Metal-Insulator Transition Material VO(2).

    Science.gov (United States)

    Martens, K; Jeong, J W; Aetukuri, N; Rettner, C; Shukla, N; Freeman, E; Esfahani, D N; Peeters, F M; Topuria, T; Rice, P M; Volodin, A; Douhard, B; Vandervorst, W; Samant, M G; Datta, S; Parkin, S S P

    2015-11-06

    The intrinsic field effect, the change in surface conductance with an applied transverse electric field, of prototypal strongly correlated VO(2) has remained elusive. Here we report its measurement enabled by epitaxial VO(2) and atomic layer deposited high-κ dielectrics. Oxygen migration, joule heating, and the linked field-induced phase transition are precluded. The field effect can be understood in terms of field-induced carriers with densities up to ∼5×10(13)  cm(-2) which are trongly localized, as shown by their low, thermally activated mobility (∼1×10(-3)  cm(2)/V s at 300 K). These carriers show behavior consistent with that of Holstein polarons and strongly impact the (opto)electronics of VO(2).

  17. VO2 thin films synthesis for collaborators and various applications.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Raegan Lynn [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Clem, Paul G. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2016-11-01

    Vanadium dioxide (VO2) is an attractive material for a variety of applications due to its metal-to-insulator transition (MIT) observed at modest temperatures. This transition takes VO2 from its low temperature insulating monoclinic phase to a high temperature (above 68°C) metallic rutile phase. This transition gives rise to a change in resistivity up to 5 orders of magnitude and a change in complex refractive index (especially at IR wavelengths), which is of interest for radar circuit protection and tunable control of infrared signature. Recently, collaborations have been initiated between CINT scientists and external university programs. The Enhanced Surveillance funds help fund this work which enabled synthesis of VO2 films for several collaborations with internal and external researchers.

  18. Ab initio calculations to support accurate modelling of the rovibronic spectroscopy calculations of vanadium monoxide (VO)

    CERN Document Server

    McKemmish, Laura K; Tennyson, Jonathan

    2016-01-01

    Accurate knowledge of the rovibronic near-infrared and visible spectra of vanadium monoxide (VO) is very important for studies of cool stellar and hot planetary atmospheres. Here, the required ab initio dipole moment and spin-orbit coupling curves for VO are produced. This data forms the basis of a new VO line list considering 13 different electronic states and containing over 277 million transitions. Open shell transition, metal diatomics are challenging species to model through ab initio quantum mechanics due to the large number of low-lying electronic states, significant spin-orbit coupling and strong static and dynamic electron correlation. Multi-reference configuration interaction methodologies using orbitals from a complete active space self-consistent-field (CASSCF) calculation are the standard technique for these systems. We use different state-specific or minimal-state CASSCF orbitals for each electronic state to maximise the calculation accuracy. The off-diagonal dipole moment controls the intensity...

  19. Fabrication and photoelectrocatalytic properties of nanocrystalline monoclinic BiVO4 thin-film electrode

    Institute of Scientific and Technical Information of China (English)

    Bin Zhou; Jiuhui Qu; Xu Zhao; Huijuan Liu

    2011-01-01

    Monoclinic bismuth vanadate (BiVO4) thin film was fabricated on indium-tin oxide glass from an amorphous heteronuclear complex via dip-coating.After annealation at 400, 500, and 600℃, the thin films were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectrophotometry.The BiVO4 particles on the ITO glass surface had a monoclinic structure.The UV-Visible diffuse reflection spectra showed the BiVO4 thin film had photoabsorption properties, with a band gap around 2.5 eV.In addition, the thin film showed high visible photocatalytic activities towards 2,4-dichiorophenol and Bisphenol A degradation under visible light irradiation (λ.> 420 nm).Over 90% of the two organic pollutants were removed in 5 hr.A possible degradation mechanism of 2,4-dichlorophenol were also studied.

  20. Direct observation of the M2 phase with its Mott transition in a VO2 film

    Science.gov (United States)

    Kim, Hoon; Slusar, Tetiana V.; Wulferding, Dirk; Yang, Ilkyu; Cho, Jin-Cheol; Lee, Minkyung; Choi, Hee Cheul; Jeong, Yoon Hee; Kim, Hyun-Tak; Kim, Jeehoon

    2016-12-01

    In VO2, the explicit origin of the insulator-to-metal transition is still disputable between Peierls and Mott insulators. Along with the controversy, its second monoclinic (M2) phase has received considerable attention due to the presence of electron correlation in undimerized vanadium ions. However, the origin of the M2 phase is still obscure. Here, we study a granular VO2 film using conductive atomic force microscopy and Raman scattering. Upon the structural transition from monoclinic to rutile, we observe directly an intermediate state showing the coexistence of monoclinic M1 and M2 phases. The conductivity near the grain boundary in this regime is six times larger than that of the grain core, producing a donut-like landscape. Our results reveal an intra-grain percolation process, indicating that VO2 with the M2 phase is a Mott insulator.

  1. Metal-insulator transition in nanocomposite VO{sub x} films formed by anodic electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Lok-kun; Lu, Jiwei; Zangari, Giovanni, E-mail: gz3e@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., Charlottesville, Virginia 22904 (United States); Hildebrand, Helga; Schmuki, Patrik [Department for Materials Science LKO, University of Erlangen-Nuremberg, Martensstr. 7, D-91058 Erlangen (Germany)

    2013-11-11

    The ability to grow VO{sub 2} films by electrochemical methods would open a low-cost, easily scalable production route to a number of electronic devices. We have synthesized VO{sub x} films by anodic electrodeposition of V{sub 2}O{sub 5}, followed by partial reduction by annealing in Ar. The resulting films are heterogeneous, consisting of various metallic/oxide phases and including regions with VO{sub 2} stoichiometry. A gradual metal insulator transition with a nearly two order of magnitude change in film resistance is observed between room temperature and 140 °C. In addition, the films exhibit a temperature coefficient of resistance of ∼ −2.4%/ °C from 20 to 140 °C.

  2. Negative capacitance switching via VO2 band gap engineering driven by electric field

    Science.gov (United States)

    He, Xinfeng; Xu, Jing; Xu, Xiaofeng; Gu, Congcong; Chen, Fei; Wu, Binhe; Wang, Chunrui; Xing, Huaizhong; Chen, Xiaoshuang; Chu, Junhao

    2015-03-01

    We report the negative capacitance behavior of an energy band gap modulation quantum well with a sandwich VO2 layer structure. The phase transition is probed by measuring its capacitance. With the help of theoretical calculations, it shows that the negative capacitance changes of the quantum well device come from VO2 band gap by continuously tuning the temperature or voltage. Experiments reveal that as the current remains small enough, joule heating can be ignored, and the insulator-metal transition of VO2 can be induced by the electric field. Our results open up possibilities for functional devices with phase transitions induced by external electric fields other than the heating or electricity-heat transition.

  3. Dy3+ activated LaVO4 films synthesized by precursors with different solution concentrations

    Institute of Scientific and Technical Information of China (English)

    WU Dandan; MA Yongqing; ZHANG Xian; QIAN Shibing; ZHENG Ganhong; WU Mingzai; LI Guang; SUN Zhaoqi

    2012-01-01

    Using different-solution-concentration precursors with citric acid as chelating agent and polyvinyl alcohol as dispersing media,Dy3+ activated LaVO4 films were deposited on indium tin oxide (ITO) substrates.The scanning electronic microscope (SEM) showed that the compact and crack-free LaVO4:Dy3+ film could be obtained at a suitable solution concentration.The deposited films could absorb the ultraviolet light below 400 nm and were transparent in the visible and infrared region as evidenced by the transmission spectra,and the photoluminescence spectra exhibited the characteristic emissions of Dy3+ peaking at 484 (blue) and 576 (yellow) nm due to the transitions of 4F9/2→6H15/2 and 4Fg/2→6H13/2,respectively.The potential application of LaVO4:Dy3+ film in the dye-sensitized solar cell (DSSC) was also discussed.

  4. 基于VoIP空管地空通信系统关键技术的研究%Based on the research of key technology VoIP for the ground-to-air communication systems

    Institute of Scientific and Technical Information of China (English)

    曾超平

    2015-01-01

    With the rapid development of computer technology and network technology, VoIP has become the way forward for voice communications. Achieved through VoIP telephone network and the Internet gateway network for voice communications, making telephone network and Internet network anywhere can communicate with the Internet. This paper first introduces the basic principles of VoIP technology, and then analyze the ATC system air-ground communications existing transmission network, and finally focus on VoIP applications in civil aviation air-ground pipe system communication.%随着计算机技术和网络技术的快速发展,VoIP成为语音通信的前进方向。通过VoIP网关实现电话网和Internet网络进行语音通信,使得电话网和Internet网在任何地方可以相互联网通信。文章首先介绍VoIP技术基本原理,然后再分析空管系统地空通信现有的传输网络,最后重点讨论VoIP在民航空管系统地空通信中的应用。

  5. Caracterização Hidrossedimentológica e dos Processos Evolutivos de Voçoroca em Área de Rochas Gináissicas do Alto Rio das Velhas (MG

    Directory of Open Access Journals (Sweden)

    Flávio Nasser Drumond

    2006-12-01

    Full Text Available Neste trabalho procurou-se caracterizar os processos erosivos e as taxas históricas de evolução de uma voçoroca em área de gnaisses do Complexo Bação, Quadrilátero Ferrífero (MG, na bacia do alto rio das Velhas. Na área predominam latossolos vermelho-amarelos, com horizontes superficiais areno-argilosos, pouco erodíveis, sobre saprolitos areno-siltosos, muito erodíveis. A evolução erosiva, avaliada por aerofotogrametria e em campo, indicou que a voçoroca, inicialmente de forma linear e de evolução lenta (entre 1951 e 1977, passou a adquirir forma mais anfiteátrica e a avançar mais rapidamente entre 1977 e 1986. Esta mudança pode ser explicada pela superação de um nível de base local (knickpoint. Entre 1986 e 2006, as taxas de avanço decresceram, possivelmente em função da diminuição da área de contribuição à montante. Os principais processos erosivos identificados na voçoroca foram: erosão hídrica superficial (laminar; em sulcos; em alcovas de regressão; e salpicamento; escorregamentos rotacionais que envolvem todo o talude; escorregamentos planares nos segmentos com rocha alterada; queda de blocos de solo; rastejos, nos sopés dos taludes com exfiltração do lençol freático, que podem resultar em pequenos escorregamentos rotacionais. Os processos de erosão são mais intensos no período chuvoso, mas os rastejos e pequenos escorregamentos são igualmente freqüentes na estiagem, quando o lençol freático atinge a cota máxima. O monitoramento hidrossedimentológico na voçoroca incluiu a coleta diária de dados: pluviométricos; de vazão na drenagem interna; de sedimentos transportados; e do nível do lençol freático. O transporte de sedimentos se correlaciona mais com os dados pluviométricos e menos com os dados de vazão, talvez porque nos meados do ano o fluxo de base, de menor erosividade, é mais intenso. Como os taludes mais ativos são aqueles sob exfiltração do lençol freático, a vo

  6. Wear Behavior of a NiCr/AgVO3 Self-Lubricating Composite

    Institute of Scientific and Technical Information of China (English)

    Wenting ZHANG; Lingzhong DU; Hao LAN; Chuanbing HUANG; Weigang ZHANG

    2013-01-01

    NiCr/AgVO3 self-lubricating composite was prepared by powder cold-pressed method with the NiCr alloy as the matrix and 10 wt.% additive of AgVO3 as solid lubricant.The AgVO3 additive powder was synthesized by the precipitation method which exhibits a melting point of 460 ℃.Microstructure,phase composition and thermal properties of the AgVO3 powder,as well as the composite of NiCr/AgVO3 were analyzed using scanning electron microscopy (SEM),transmission electron microscopy (TEM),X-ray diffraction (XRD) and differential scanning calorimeter (DSC).The friction and wear behavior of the specimens from room temperature (R.T.)to 800 ℃ was evaluated using a ball-on-disk tribometer and 3D white light interference (WLI).The results showed that the friction coefficient of this material under atmosphere decreases with temperature increasing from R.T.to 800 ℃.However,the wear rate firstly increases from R.T.to 200 ℃,almost remains stable from 200 ℃ to 600 ℃,and then decreases with further increasing the temperature up to 800 ℃.It is also found that the prepared composite materials show a better frictional behavior than NiCr alloy over the whole range of temperatures,which is mainly attributed to solid lubrication of AgVO3 exhibiting a lamella-slip structure at temperatures below 460 ℃ and forms liquid-film at elevated temperatures above the melting point.

  7. Markers of inflammation are inversely associated with VO2 max in asymptomatic men.

    Science.gov (United States)

    Kullo, Iftikhar J; Khaleghi, Mahyar; Hensrud, Donald D

    2007-04-01

    We investigated whether markers of inflammation, including a cytokine (IL-6), acute-phase reactants [C-reactive protein (CRP) and fibrinogen], and white blood cell (WBC) count are associated with maximal O(2) consumption (Vo(2 max)) in men without coronary heart disease (CHD). In asymptomatic men (n = 172, 51 +/- 9.3 yr old), Vo(2 max) was measured during a symptom-limited graded treadmill exercise test. Physical activity level was assessed by a standardized questionnaire. IL-6 and CRP were measured by immunoassays, fibrinogen by the Clauss method, and WBC count with a Coulter counter. IL-6 and CRP were logarithmically transformed to reduce skewness. Multivariable regression was used to assess whether markers of inflammation were associated with Vo(2 max) after adjustment for age, body mass index, CHD risk factors, and lifestyle variables (physical activity level, percent body fat, and alcohol intake). Vo(2 max) was 34.5 ml.kg(-1).min(-1) (SD 6.1). Log IL-6 (r = -0.38, P max). In separate multivariable linear regression models that adjusted for age, body mass index, CHD risk factors, and lifestyle variables, log IL-6 [beta-coeff = -1.66 +/- 0.63 (SE), P = 0.010], log CRP [beta-coeff = -0.99 +/- 0.33 (SE), P = 0.003], fibrinogen [beta-coeff = -1.51 +/- 0.44 (SE), P = 0.001], and WBC count [beta-coeff = -0.52 +/- 0.30 (SE), P = 0.088] were each inversely associated with Vo(2 max). In conclusion, higher circulating levels of IL-6, CRP, and fibrinogen are independently associated with lower Vo(2 max) in asymptomatic men.

  8. Induction of cyto-protective autophagy by paramontroseite VO2 nanocrystals

    Science.gov (United States)

    Zhou, Wei; Miao, Yanyan; Zhang, Yunjiao; Liu, Liang; Lin, Jun; Yang, James Y.; Xie, Yi; Wen, Longping

    2013-04-01

    A variety of inorganic nanomaterials have been shown to induce autophagy, a cellular degradation process critical for the maintenance of cellular homeostasis. The overwhelming majority of autophagic responses elicited by nanomaterials were detrimental to cell fate and contributed to increased cell death. A widely held view is that the inorganic nanoparticles, when encapsulated and trapped by autophagosomes, may compromise the normal autophagic process due to the inability of the cells to degrade these materials and thus they manifest a detrimental effect on the well-being of a cell. Here we show that, contrary to this notion, nano-sized paramontroseite VO2 nanocrystals (P-VO2) induced cyto-protective, rather than death-promoting, autophagy in cultured HeLa cells. P-VO2 also caused up-regulation of heme oxygenase-1 (HO-1), a cellular protein with a demonstrated role in protecting cells against death under stress situations. The autophagy inhibitor 3-methyladenine significantly inhibited HO-1 up-regulation and increased the rate of cell death in cells treated with P-VO2, while the HO-1 inhibitor protoporphyrin IX zinc (II) (ZnPP) enhanced the occurrence of cell death in the P-VO2-treated cells while having no effect on the autophagic response induced by P-VO2. On the other hand, Y2O3 nanocrystals, a control nanomaterial, induced death-promoting autophagy without affecting the level of expression of HO-1, and the pro-death effect of the autophagy induced by Y2O3. Our results represent the first report on a novel nanomaterial-induced cyto-protective autophagy, probably through up-regulation of HO-1, and may point to new possibilities for exploiting nanomaterial-induced autophagy for therapeutic applications.

  9. QoS technology of VoIP based on 3 G Mobile Communication%3G手机VoIP话音的QoS实现技术研究

    Institute of Scientific and Technical Information of China (English)

    梁鸿斌

    2014-01-01

    在对3 G手机VoIP话音QoS的主要实现技术进行分析的基础上,提出了3 G手机VoIP话音QoS新的实现技术。文中通过对实时传输控制协议( RTCP协议)的详细研究,同时根据3 G系统无线信道的具体特点,说明了实时传输控制协议运用于3 G手机VoIP话音的QoS控制中的缺陷,并阐述了相应的控制解决方法。在基于Android的3 G智能手机的VoIP客户端软件中,综合运用VoIP话音QoS的主要成熟实现技术,同时结合文中提出的VoIP话音QoS的解决思路,实现了对VoIP话音的QoS的控制。基于Android的3 G智能手机的VoIP客户端软件通过在不同的网络环境条件下的测试,VoIP话音质量良好,说明文中提出的3G手机VoIP话音QoS新的实现技术具有一定的实用价值。%On the basis of analyzing the main realization technology of 3G mobile phone VoIP voice of QoS, a new implementation technique of 3G mobile phone VoIP voice of QoS is proposed. After studying the RTCP(Real-time Transport Control Protocol) and the features of 3G wireless communication channel, the imperfection of the RTCP protocol applying to the VoIP QoS control over 3 G mobile communications is presented, and then the corresponding solution is described subsequently. Both of the mature QoS technol-ogy and the methods presented in this paper are applied to android client software running on 3 G cell-phone, and then the voice quality over different network conditions is tested. The test results show that the voice quality becomes better, which presents the new QoS technology of 3G VoIP mobile communication discussed in this thesis is practical.

  10. ITRG:VoIP未来三年将取代传统语音通讯

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    知名的市场研究单位ITRG(Info—Tech Research Group)日前表示,VoIP技术(Voice over Internet Protocol)将会迅速席卷通信市场,三年内会取代传统的电话语音通讯。目前,已有25%的中型企业已经采用VoIP,预计未来三年内更会提升到50%。

  11. Vertailussa VoIP- ja GSM- järjestelmä

    OpenAIRE

    Kopsala, Laura

    2013-01-01

    GSM on maailman laajuisesti käytetty matkapuhelinjärjestelmä. Suomessa ensimmäinen GSM-toimilupa myönnettin Radiolinjalle vuonna 1990. GSM matkapuhelinjärjestelmä on lisännyt suosiotaan ja järjestelmä on hyvin pitkälle syrjäyttänyt perinteiset lankapuhelinverkot. Suomessa on käytössä kaksi matkapuhelin taajuutta. Internetin ja tekniikan kehityksen myötä VoIP:sta eli Internet-puheesta on tullut varteen otettava vaihtoehto GSM-matkapuhelin järjestelmälle. VoIP mahdollistaa puheen ja videoku...

  12. Efficient, resonantly pumped, room-temperature Er3+:GdVO4 laser.

    Science.gov (United States)

    Ter-Gabrielyan, N; Fromzel, V; Ryba-Romanowski, W; Lukasiewicz, T; Dubinskii, M

    2012-04-01

    We report an efficient room-temperature operation of a resonantly pumped Er3+:GdVO4 laser at 1598.5 nm. The maximum continuous wave (CW) output power of 3.5 W with slope efficiency of 56% was achieved with resonant pumping by an Er-fiber laser at 1538.6 nm. With pumping by a commercial laser diode bar stack, a quasi-CW (QCW) output of 7.7 W and maximum slope efficiency of ~53% versus absorbed pump power were obtained. This is believed to be the first resonantly (in-band) pumped, room-temperature Er3+:GdVO4 laser.

  13. Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Fischer, Bernd M.; Thoman, Andreas

    2006-01-01

    We investigate the dielectric properties of a thin VO2 film in the terahertz frequency range in the vicinity of the semiconductor-metal phase transition. Phase-sensitive broadband spectroscopy in the frequency region below the phonon bands of VO2 gives insight into the conductive properties...... of the film during the phase transition. We compare our experimental data with models proposed for the evolution of the phase transition. The experimental data show that the phase transition occurs via the gradual growth of metallic domains in the film, and that the dielectric properties of the film...

  14. SIP协议在VoIP中的研究与实现

    Institute of Scientific and Technical Information of China (English)

    李难; 董德存

    2006-01-01

    SIP协议是VoIP体系中的重要协议,属于多媒体数据和控制体系。本文详细地介绍了SIP协议的体系结构、消息机制鬯苎鼍叫控制过程:算左此基础上提出了一种SIP协议栈的实现方案。该协议栈适用于VoIP电话系统,体现了SIP协议简练、开放、兼容、可扩展等特点。

  15. High-temperature heat capacity of orthovanadates Ce1- x Bi x VO4

    Science.gov (United States)

    Denisova, L. T.; Chumilina, L. G.; Belousova, N. V.; Denisov, V. M.

    2016-09-01

    Orthovanadates Ce1- x Bi x VO4 (1 ≥ x ≥ 0) have been produced by solid-phase synthesis from initial oxides CeO2, Bi2O3, and V2O5 upon step-by-step burning. The high-temperature heat capacity of Ce1- x Bi x VO4 has been measured by differential scanning calorimetry. The experimental data on C p = f(T) were used to calculate the thermodynamic properties (the enthalpy changes, the entropy changes, and the Gibbs energy).

  16. Frequency of the VO2max plateau phenomenon in world-class cyclists.

    Science.gov (United States)

    Lucía, A; Rabadán, M; Hoyos, J; Hernández-Capilla, M; Pérez, M; San Juan, A F; Earnest, C P; Chicharro, J L

    2006-12-01

    We aimed to determine the frequency of the VO2max plateau phenomenon in top-level male professional road cyclists (n = 38; VO2max [mean +/- SD]: 73.5 +/- 5.5 ml.kg(-1).min(-1)) and in healthy, sedentary male controls (n = 37; VO2max: 42.7 +/- 5.6 ml.kg(-1).min(-1)). All subjects performed a continuous incremental cycle-ergometer test of 1-min workloads until exhaustion. Power output was increased from a starting value of 25 W (cyclists) or 20 W (controls) at the rate of 25 W.min(-1) (cyclists) or 20 W.min(-1) (controls) until volitional exhaustion. We measured gas-exchange and heart rate (HR) throughout the test. Blood concentrations of lactate (BLa) were measured at end-exercise in both groups. We defined maximal exercise exertion as the attainment of a respiratory exchange rate (RER) >or= 1.1; HR > 95 % age-predicted maximum; and BLa > 8 mmo.l(-1). The VO2max plateau phenomenon was defined as an increase in two or more consecutive 1-min mean VO2 values of less than 1.5 ml.kg(-1).min(-1). Most cyclists met our criteria for maximal exercise effort (RER > 1.1, 100 %; 95 % predicted maximal HR [HRmax], 82 %; BLa > 8 mmol.l(-1), 84 %). However, the proportion of cyclists attaining a V.O (2max) plateau was considerably lower, i.e., 47 %. The majority of controls met the criteria for maximal exercise effort (RER > 1.1, 100 %; predicted HRmax, 68 %; BLa > 8 mmol. l(-1), 73 %), but the proportion of these subjects with a VO2max plateau was only 24 % (significantly lower proportion than in cyclists [p < 0.05]). Scientists should consider 1) if typical criteria of attainment of maximal effort are sufficiently stringent, especially in elite endurance athletes; and 2) whether those humans exhibiting the VO2max plateau phenomenon are those who perform an absolute maximum effort or there are additional distinctive features associated with this phenomenon.

  17. Performance Study of Objective Speech Quality Measurement for Modern Wireless-VoIP Communications

    Directory of Open Access Journals (Sweden)

    Chan Wai-Yip

    2009-01-01

    Full Text Available Wireless-VoIP communications introduce perceptual degradations that are not present with traditional VoIP communications. This paper investigates the effects of such degradations on the performance of three state-of-the-art standard objective quality measurement algorithms—PESQ, P.563, and an "extended" E-model. The comparative study suggests that measurement performance is significantly affected by acoustic background noise type and level as well as speech codec and packet loss concealment strategy. On our data, PESQ attains superior overall performance and P.563 and E-model attain comparable performance figures.

  18. Understanding VoIP Internet Telephony and the Future Voice Network

    CERN Document Server

    Flanagan, William A

    2012-01-01

    Translates technical jargon into practical business communications solutions This book takes readers from traditional voice, fax, video, and data services delivered via separate platforms to a single, unified platform delivering all of these services seamlessly via the Internet. With its clear, jargon-free explanations, the author enables all readers to better understand and assess the growing number of voice over Internet protocol (VoIP) and unified communications (UC) products and services that are available for businesses. VoIP and Unified Communications is based on the author's careful rev

  19. P2P assisted streaming for low popularity VoD contents

    OpenAIRE

    Gramatikov, Sasho; Jaureguizar Núñez, Fernando; Mishkovski, Igor; Cabrera Quesada, Julian; García Santos, Narciso

    2013-01-01

    The Video on Demand (VoD) service is becoming a dominant service in the telecommunication market due to the great convenience regarding the choice of content items and their independent viewing time. However, due to its high traffic demand nature, the VoD streaming systems are faced with the problem of huge amounts of traffic generated in the core of the network, especially for serving the requests for content items that are not in the top popularity range. Therefore, we propose a peer assist...

  20. Assessment of measurement properties of peak VO2 in children with pulmonary arterial hypertension

    Directory of Open Access Journals (Sweden)

    Cappelleri Joseph C

    2012-09-01

    Full Text Available Abstract Background The 6-minute walk test evaluates the effect of pharmacologic intervention in adults with pulmonary arterial hypertension (PAH but, for reasons of compliance or reliability, may not be appropriate for children at all ages. Thus, peak oxygen consumption (VO2, maximal exercise test was used instead in a pediatric PAH trial (STARTS-1 to evaluate pharmacologic intervention with sildenafil. This was the first large placebo-controlled trial to use the peak VO2 endpoint in this population. Our working hypothesis was that, as with other populations, percentage changes in peak VO2 in pediatric patients with PAH are reliable and are associated with changes in other clinical endpoints. Methods Using data from the subpopulation of 106 patients who were developmentally and physically able to perform exercise testing, all of whom were World Health Organization Functional Class (WHO FC I, II, or III, reliability was assessed using the intraclass correlation coefficient and Bland-Altman plot on screening and baseline data. Relationships between percentage change in peak VO2 from baseline to end of treatment and other endpoints were evaluated using correlation coefficients and regression analyses. Results The intraclass correlation was 0.79 between screening and baseline peak VO2, an agreement that was supported by the Bland-Altman plot. Percentage change in peak VO2 correlated well (r ≥0.40 and showed responsiveness to a physician global assessment of change and with change in WHO FC (for baseline classes I and III. Percentage change in peak VO2 did not correlate with change in the Family Cohesion of the Child Health Questionnaire (r = 0.04 or with a subject global assessment of change (r = 0.12. The latter may have been influenced by child and parental-proxy response and instrument administration. Conclusion In pediatric PAH patients who are developmentally and physically able to perform exercise testing, peak VO2 measurements

  1. 无线VoIP语音通信系统的设计实现

    Institute of Scientific and Technical Information of China (English)

    栾颖; 涂友斌; 宋铁成; 连平

    2008-01-01

    文章基于无线通信的复杂环境,设计并实现了一种无线VoIP语音通话系统.该系统通过改进传统VoIP通信系统网络架构,增加了SBC和WAC模块,同时应用SIP协议提供高质量的语音.经调试并试用,系统工作稳定,通话质量良好.

  2. Combustion synthesis of Eu2+ and Dy3+ activated Sr3(VO4)2 phosphor for LEDs

    Indian Academy of Sciences (India)

    Roshani Singh; S J Dhoble

    2011-06-01

    Combustion synthesis and photoluminescence (PL) characterization of Sr3(VO4)2:Eu,Dy phosphors are presented in this paper. PL emission of Sr3(VO4)2:Eu phosphor shows green broad emission band centring at 511 nm and a red sharp band at 614 nm by excitation wavelength of 342 nm. The PL emission spectrum of Sr3(VO4)2:Dy phosphor exhibits an intense blue emission peak at 479 nm, yellow broad band centring at 573 nm and red band at 644 nm by the excitation wavelength of 426 nm in near visible blue region. The excitation wavelength of Eu (342 nm) and Dy (426 nm) activated Sr3(VO4)2 phosphor are well matched with the excitation of near UV excited solid state lighting and blue chip excitation of light emitting diodes, respectively. The effect of Eu2+ and Eu3+ ions concentration on the emission intensity of Sr3(VO4)2 was also investigated. The Sr3(VO4)2:Eu is a potential green and red emitting phosphor as well as Sr3(VO4)2:Dy is blue and yellow emitting phosphor for solid state lighting i.e. white LEDs. The XRD and SEM characteristics of Sr3(VO4)2 materials was also reported in this paper.

  3. Voice over Internet Protocol (VoIP) Technology as a Global Learning Tool: Information Systems Success and Control Belief Perspectives

    Science.gov (United States)

    Chen, Charlie C.; Vannoy, Sandra

    2013-01-01

    Voice over Internet Protocol- (VoIP) enabled online learning service providers struggling with high attrition rates and low customer loyalty issues despite VoIP's high degree of system fit for online global learning applications. Effective solutions to this prevalent problem rely on the understanding of system quality, information quality, and…

  4. Estudio cinético del proceso de devolatilización de biomasa lignocelulósica mediante análisis termogravimétrico para tamaños de partícula de 2 a 19 mm

    OpenAIRE

    ANDRÉS MELGAR; DAVID BORGE; Juan F. Pérez

    2008-01-01

    Con el objetivo de proporcionar herramientas que mejoren el diseño de los sistemas de gasificación/combustión de biomasa, y los modelos cinético-químicos de dichos procesos, se presenta un estudio de la cinética química asociada al proceso de devolatilización de biomasa mediante pruebas de termogravimetría utilizando tamaños de partícula que varían de 2 a 19 mm, y tasas de calentamiento de 10, 15 y 20 K/min. El desarrollo de este trabajo se justifica debido a que no hay resultados disponibles...

  5. Balance sheet of the first year of O&M at the Ence biomass plant in Mérida; Balance del primer año de operación y mantenimiento de la planta de biomasa de Ence en Mérida

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-07-01

    Having received the Final Commissioning Protocol from the Ministry of Agriculture, Rural Development, Environment and Energy of the Extremadura Regional Government, Ence’s biomass generation plant in Mérida started to deliver energy to the electrical system in April 2014. With the construction and commissioning of the Sener turnkey project for the biomass plant having been completed, Ence - the engineering and technology group – set up the company Biomasa Mérida O&M S.L. to provide operation and maintenance works for the facility’s first two years of operation. Following signature of the provisional acceptance of the plant by Ence, Biomasa Mérida O&M S.L. accepted its mission and started work on 15 September 2014. (Author)

  6. QoS Management Mechanisms and Prototype System of VoIP%VoIP服务质量管理机制及原型系统

    Institute of Scientific and Technical Information of China (English)

    陈秀忠; 王春峰; 黄晓潞

    2003-01-01

    In this paper, we briefly introduce the architecture of VoIP application at the beginning. Then we focus on discussing QoS management mechanisms in data plane and control plane in detail. We explore the implementation of QoS management system by describing the prototype system QNet. At last, we discuss their future trends and present several issues remained to be studied by combining the experiences of our research.

  7. VoIP network Based on SIP and its intercommunication with the PSTN%基于SIP协议的VoIP及与PSTN的互通

    Institute of Scientific and Technical Information of China (English)

    吕海容; 师向群

    2007-01-01

    SIP协议具有简单、灵活的技术特点,成为下一代网络中语音信息传输的主要形式.研究基于SIP协议的VoIP体系结构,描述SIP消息结构、呼叫流程,针对基于SIP的VOIP与PSTN之间协议转换作了深度分析.

  8. IEEE802.11下VoIP的M-M-M机制%M-M-M Mechanism of VoIP In IEEE802.11

    Institute of Scientific and Technical Information of China (English)

    马圣政; 曾桂根

    2008-01-01

    根据M-M帧和普通多播帧的本质区别,建立在M-M基础上的M-M-M机制,按信道速率分类后再把下行语音帧聚合多播.分析表明,M-M-M机制进一步提高了VoWLAN的网络容量.

  9. Tribological properties of self-lubricating NiAl/Mo-based composites containing AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Eryong, E-mail: ley401@163.com [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Gao, Yimin, E-mail: ymgao@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Bai, Yaping, E-mail: jingpingxue2004@163.com [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yi, Gewen, E-mail: gwyi@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Wenzhen, E-mail: Wzwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zeng, Zhixiang, E-mail: zengzhx@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Jia, Junhong, E-mail: jhjia@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-11-15

    Silver vanadate (AgVO{sub 3}) nanowires were synthesized by hydrothermal method and self-lubricating NiAl/Mo-AgVO{sub 3} composites were fabricated by powder metallurgy technique. The composition and microstructure of NiAl/Mo-based composites were characterized and the tribological properties were investigated from room temperature to 900 °C. The results showed that NiAl/Mo-based composites were consisted of nanocrystalline B2 ordered NiAl matrix, Al{sub 2}O{sub 3}, Mo{sub 2}C, metallic Ag and vanadium oxide phase. The appearance of metallic Ag and vanadium oxide phase can be attributed to the decomposition of AgVO{sub 3} during sintering. Wear testing results confirmed that NiAl/Mo-based composites have excellent tribological properties over a wide temperature range. For example, the friction coefficient and wear rate of NiAl/Mo-based composites containing AgVO{sub 3} were significantly lower than the composites containing only metallic Mo or AgVO{sub 3} lubricant when the temperature is above 300 °C, which can be attributed to the synergistic lubricating action of metallic Mo and AgVO{sub 3} lubricants. Furthermore, Raman results indicated that the composition on the worn surface of NiAl-based composites was self-adjusted after wear testing at different temperatures. For example, Ag{sub 3}VO{sub 4} and Fe{sub 3}O{sub 4} lubricants were responsible for the improvement of tribological properties at 500 °C, AgVO{sub 3}, Ag{sub 3}VO{sub 4} and molybdate for 700 °C, and AgVO{sub 3} and molybdate for 900 °C of NiAl-based composites with the addition of metallic Mo and AgVO{sub 3}. - Highlights: • NiAl/Mo-AgVO{sub 3} nanocomposites were prepared by mechanical alloying and sintering. • AgVO{sub 3} decomposed to metallic Ag and vanadium oxide during the sintering process. • NiAl/Mo-AgVO{sub 3} exhibited superior tribological properties at a board temperature range. • Phase composition on the worn surface was varied with temperatures. • Self-adjusted action

  10. Synthesis and the enhanced visible-light-driven photocatalytic activity of BiVO4 nanocrystals coupled with Ag nanoparticles

    Science.gov (United States)

    Wang, W. Z.; Meng, Shan; Tan, Miao; Jia, L. J.; Zhou, Y. X.; Wu, Shuang; Huang, X. W.; Liang, Y. J.; Shi, H. L.

    2015-03-01

    BiVO4 nanocrystals coupled with Ag nanoparticles (Ag-BiVO4 heterogeneous nanostructures) have been prepared by a new strategy via combining a hydrothermal route with a polyol process, in which BiVO4 nanocrystals were first synthesized by a hydrothermal route, and then, Ag nanoparticles were grown on the surfaces of the presynthesized BiVO4 nanocrystals through a polyol process. The photocatalytic evaluations demonstrate that BiVO4 nanocrystals coupled with Ag nanoparticles exhibit the enhanced visible-light-driven photocatalytic activity for the degradation of methylene blue (MB) and rhodamine B (RhB). The energy alignment and diffuse reflectance property of Ag-BiVO4 heterogeneous nanostructures demonstrate that Ag nanoparticles attached on the surfaces of BiVO4 nanocrystals play double roles for the enhanced visible-light-driven photocatalytic activity. First, the Ag nanoparticles grown on the surfaces of BiVO4 nanocrystals may act as electron sinks to retard the recombination of the photogenerated electrons and holes in BiVO4 so as to improve the charge separation on its surfaces. Second, the Ag nanoparticles increase the visible light absorption of the Ag-BiVO4 photocatalyst due to surface plasmon resonance (SPR) of Ag nanoparticles. These double roles of Ag nanoparticles make Ag-BiVO4 heterogeneous nanostructures to exhibit the enhanced photocatalytic activity to decompose MB and RhB under visible light irradiation, compared to the pure BiVO4 nanocrystals. The enhanced photocatalytic activity is attributed to the charge transfer from BiVO4 to the attached Ag nanoparticles as well as SPR absorption of Ag nanoparticles. The present work not only provides an efficient route to enhance visible-light-driven photocatalytic activity of BiVO4, but also offers a new strategy for fabricating metal-semiconductor heterogeneous nanostructure photocatalysts, which are expected to show considerable potential applications in solar-driven wastewater treatment and water

  11. 基于FTO/VO2/FTO结构的VO2薄膜电压诱导相变光调制特性∗%Optical mo dulation characteristics of VO2 thin film due to electric field induced phase transition in the FTO/VO2/FTO structure

    Institute of Scientific and Technical Information of China (English)

    郝如龙; 方宝英; 王晓华; 肖寒; 李毅; 刘飞; 孙瑶; 唐佳茵; 陈培祖; 蒋蔚; 伍征义; 徐婷婷

    2015-01-01

    VO2 thin films have been studied for their semiconductor–metal reversible transition from the monoclinic to the rutile structure, where the electrical and optical properties undergo a drastic change by increasing the temperature or by applying a voltage. VO2 film is becoming a promising material for optical switch, optical storage, optical modulator, smart window, and micro-bolometer. The preparation procedures of the FTO/VO2/FTO structure in detail are as follows:First, the F-doped SnO2 conductive glass (FTO) substrates are cleaned sequentially in acetone, ethanol, and deionized water for 10 min using an ultrasonic cleaning equipment at a frequency of 20 kHz. When the FTO substrates was cleaned, they are dried with nitrogen. Second, the dried FTO substrates are placed in the chamber of a DC magnetron sputtering system equipped with a high-purity metal target of V (99.9%). After argon (99.999%) of 80 sccm flux was discharged with the current of 2 A and the voltage of 400 V for 2 min, the vanadium films are deposited on the FTO substrates. Third, the prepared vanadium films are annealed for different annealing time in an atmosphere composed of different proportions of nitrogen-oxygen. Then another layer thickness of 350 nm of FTO conductive film is deposited on the VO2 thin film by using the plasma enhanced chemical vapor deposition method. Finally, different sizes of the FTO/VO2/FTO structure are prepared by using photolithography and chemical etching processes. The effect of different annealing time and different proportions of nitrogen-oxygen atmosphere on the VO2 thin films has been studied. X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and spectrophotometer are then used to test and analyze the crystal structure, surface morphology, surface roughness, the relative content of the surface elements, and transmittance of the VO2/FTO composite films. Results show that a relatively

  12. E ectofGoldNanoparticlesonthePhotocatalytic and Photo electro chemical Performance of Au Mo dified BiVO4

    Institute of Scientific and Technical Information of China (English)

    Mingce Long; Jingjing Jiang; Yan Li; Ruqiong Cao; Liying Zhang; Weimin Cai

    2011-01-01

    An efficient visible light driven photocatalyst, gold nanoparticles (NPs) modified BiVO4 (Au/BiVO4), has been synthesized by deposition-precipitation with urea method. Au/BiVO4 exhibits enhanced pho-tocatalytic activity for phenol degradation underλ>400 nm irradiation but negligible activity underλ>535 nm, indicating that the surface plasmon resonance (SPR) effect is too weak for organic photodegradation. According to the photoelectrochemical results of the porous powder electrodes of BiVO4 and Au/BiVO4, the SPR effect of Au NPs has been assessed. The role of Au NPs as electron sinks or sources, which is controllable by incident photon energy and applied potentials, has been discussed.

  13. Effects of crystal orientation and ferroelastic domain structure on the photochemical reactivity of BiVO4 and related compounds

    Science.gov (United States)

    Munprom, Ratiporn

    Bismuth vanadate, BiVO4, has been recognized for its high efficiency as a photoanode for water splitting. However, its performance is limited by photogenerated electron--hole recombination. Thus, researchers have attempted to modify BiVO4 to improve its performance. One strategy to improve charge separation is to utilize an internal field arising from surface termination differences. Previous studies concentrated on polygonal single crystals of BiVO4, providing limited information about the orientation-reactivity relationship. The current research focuses on polycrystalline BiVO4, which makes it possible to study the photochemical reactivity of all possible orientations and determine the complete orientation dependence of the photochemical reactivity of BiVO4. (Abstract shortened by UMI.).

  14. Synthesis of BiVO4/TiO2 composites and evaluation of their photocatalytic activity under indoor illumination.

    Science.gov (United States)

    Longo, Giulia; Fresno, Fernando; Gross, Silvia; Štangar, Urška Lavrenčič

    2014-10-01

    BiVO4/TiO2 composites with different weight ratios have been prepared by coprecipitation-based reactions followed by either thermal or hydrothermal treatment with the aim of evaluating the TiO2 photosensitization by BiVO4. The obtained materials present in all cases the desired monoclinic phase of BiVO4 and anatase phase of TiO2. Visible light absorption increased with increasing amount of bismuth vanadate. XPS results reveal the surface enrichment of Ti with respect to the bulk composition in samples characterised by a higher content of BiVO4. The photocatalytic activity of the prepared materials was tested for the degradation of isopropanol in the gas phase under indoor illumination conditions. Although none of the composites was able to improve the activity of TiO2, the low BiVO4 containing samples appear as more suitable for further synthesis tuning.

  15. PI3K/Akt pathway involving into apoptosis and invasion in human colon cancer cells LoVo.

    Science.gov (United States)

    Jiang, Qun Guang; Li, Tai Yuan; Liu, Dong Ning; Zhang, Hai Tao

    2014-05-01

    In this study we determined the effects of Curcumin on human colon cancer cells line LoVo. We found that Curcumin significantly inhibited the proliferation, migration and invasion, and clone formation of LoVo cells in a dose-dependent manner. Curcumin also dose-dependently reduced the phosphorylation of proteins Akt and increased expression levels of the genes caspase-3, cytochrome-c, Bax mRNA in LoVo cells. In addition, Curcumin dose-dependently decreased gene Bcl-2 mRNA expression. Similar results were observed in LoVo cells treated with LY294002. These in vitro studies suggest that Curcumin may play its anti-cancer actions partly via suppressing PI3K/Akt signal pathway in LoVo cells.

  16. Preparation of BiVO4 and photocatalytic degradation of RhB under visible light%钒酸铋的制备及可见光降解罗丹明B的研究

    Institute of Scientific and Technical Information of China (English)

    刘利; 王亚飞; 崔文权; 梁英华; 王萌

    2013-01-01

    BiVO4 was synthesized via hydrothermal method,with Bi(NO3)3 and NH4VO3 as raw materials and with NaOH to adjust pH of the system.Crystal structure and optical absorption properties of the as-prepared material were characterized by XRD and UV-Vis.Taking rhodamine B as degradation objective,halogen lamp(λ >400 nm)as light source,the influences of hydrothermal temperature and time on the visible photocatalytic activity of BiVO4 were investigated.Results showed that the best preparation conditions were 200 ℃ and 8 h.Influences ofpH of rhodamine B solution and dosage of catalyst on degradation rate of rhodamine B were also investigated,and results showed that when pH was 3 and catalyst's dosage was 0.4 g(per 60 mL solution),the photocatalytic effect was the best,and the photocatalytic degradation rate could reach 97% after reaction for 2h.%以偏钒酸铵和碳酸铋为原料,用NaOH调节体系pH,水热法合成钒酸铋(BiVO4)光催化剂.利用XRD和UV-Vis漫反射对样品的晶型结构和光吸收特性进行表征分析.以罗丹明B为目标降解物,卤素灯(λ>400 nm)为光源,探讨水热温度、水热时间对合成BiVO4催化剂的可见光催化活性影响.结果表明,在水热温度为200℃、水热时间为8h的条件下合成的钒酸铋光解效率最高.实验还研究了罗丹明B水溶液pH、催化剂投加量对光催化罗丹明B降解率的影响.结果表明,在罗丹明B水溶液pH为3、初始质量浓度为10 mg/L、每60 mL溶液催化剂投加量为0.4 g时能达到较好的光催化效果,反应2h后降解率可达97%.

  17. A high blood lactate induced by heavy exercise does not affect the increase in submaximal VO2 with hyperoxia.

    Science.gov (United States)

    Favier, F B; Prieur, F; Grataloup, O; Busso, T; Castells, J; Denis, C; Geyssant, A; Benoit, H

    2005-05-01

    Few studies evidenced an enhancement in oxygen uptake (VO2) during submaximal exercise in hyperoxia. This O2 "overconsumption" seems to increase above the lactate threshold. The aim of this study was to determine whether the hyperoxia-induced enhancement in VO2 may be related to a higher metabolism of lactate. Nine healthy males (aged 23.1 years, mean VO2 max= 53.8 ml min-1 kg-1) were randomized to two series of exercise in either normoxia or hyperoxia corresponding to an inspired O2 fraction (FIO2) of 30%. Each series consisted of 6 min cycling at 50% VO2 max (Moderate1), 5 min cycling at 95%VO2 max (Near Max) and then 6 min at 50% VO2 max (Moderate2). In both series Near Max was performed in normoxia. VO2 was significantly greater under hyperoxia than in normoxia during Moderate1 (2192 +/- 189 vs. 2025 +/- 172 ml min-1) and during Moderate2 (2352 +/- 173 vs. 2180+ /- 193 ml min-1). However, the effect of the high FIO2 was not significantly different on VO2Moderate2 (+172+/-137 ml min-1 with [La] approximately 6 mmol l-1) compared to VO2Moderate1 (+166 +/- 133 ml min-1 with [La] approximately 2.4 mmol l-1). [La] at the onset of Moderate2 was not different between normoxia and hyperoxia (10.1 +/- 2.2 vs. 10.9 +/- 1.6 mmol l-1). The results show that VO2 is significantly increased during moderate exercise in hyperoxia. But this O2 overconsumption was not modified by a high [La] induced by a prior heavy exercise. It could be concluded that lactate accumulation is not directly responsible for the increase in O2 overconsumption with intensity during exercise in hyperoxia.

  18. Atomic layer deposition of VO2 films with Tetrakis-dimethyl-amino vanadium (IV) as vanadium precursor

    Science.gov (United States)

    Lv, Xinrui; Cao, Yunzhen; Yan, Lu; Li, Ying; Song, Lixin

    2017-02-01

    VO2 thin films have been grown on Si(100) (VO2/Si) and fused silica substrates (VO2/SiO2) 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 VO2 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 VO2 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 VO2/Si film. AFM was applied to study the surface morphology of VO2/Si films, which showed a dense polycrystalline film with roughness of about 1 nm. The resistance of VO2/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 (Tc,h) of about 72 °C, a hysteresis width of about 10 °C and the resistance change of two orders of magnitude. The increase of Tc,h compared with the bulk VO2 (68 °C) may be attributed to the tensile stress along the c-axis in the film. Transmittance measurement of VO2/SiO2 films showed typical thermochromic property with a NIR switching efficiency of above 50% at 2 μm across the transition.

  19. Crossvalidation of two heart rate-based equations for predicting VO2max in white and black men.

    Science.gov (United States)

    Esco, Michael R; Olson, Michele S; Williford, Henry N; Mugu, Emmanuel M; Bloomquist, Barbara E; McHugh, Aindrea N

    2012-07-01

    The purpose of this investigation was to crossvalidate 2 equations that use the ratio of maximal heart rate (HRmax) to resting HR (HRrest) for predicting maximal oxygen consumption (VO2max) in white and black men. One hundred and nine white (n = 51) and black (n = 58) men completed a maximal exercise test on a treadmill to determine VO2max. The HRrest and HRmax were used to predict VO2max via the HRindex and HRratio equations. Validity statistics were done to compare the criterion versus predicted VO2max values across the entire cohort and within each race separately. For the entire group, VO2max was significantly overestimated with the HRindex equation, but the HRratio equation yielded no significant difference compared with the criterion. In addition, there were no significant differences shown between VO2max and either HR-based prediction equation for the white subgroup. However, both equations significantly overestimated VO2max in the black group. Furthermore, large standard error of estimates (ranging from 6.92 to 7.90 ml·kg(-1)·min(-1)), total errors (ranging from 8.30 to 8.62 ml·kg(-1)·min(-1)), and limits of agreement (ranging from upper limits of 16.65 to lower limits of -18.25 ml·kg(-1)·min(-1)) were revealed when comparing the predicted to criterion VO2max for both the groups. Considering the results of this investigation, the HRratio and HRindex methods appear to crossvalidate and prove useful for estimating the mean VO2max in white men as a group but not for an age-matched group of black men. However, because of inflated values for error, caution should be exercised when using these methods to predict individual VO2max.

  20. Slow VO2 off-kinetics in skeletal muscle is associated with fast PCr off-kinetics--and inversely.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2013-09-01

    The computer model of the bioenergetic system in skeletal muscle, developed previously, was used to study the effect of the characteristic decay time of the parallel activation of oxidative phosphorylation [τ(OFF)] during muscle recovery on the muscle oxygen consumption rate (Vo2) and phosphocreatine (PCr) work-to-rest transition (off)-kinetics and on the relationship between the Vo2 and PCr rest-to-work transition (on)- and off-kinetics in moderate and heavy exercise. An increase in τ(OFF) slows down the initial phase of the muscle Vo2 off-kinetics and accelerates the PCr off-kinetics. As a result, the relationship between the initial phase of the Vo2 off-kinetics (lasting approximately 3-60 s in computer simulations) and the PCr off-kinetics is inverse: the slower the former, the faster the latter. A faster initial phase of the Vo2 off-kinetics is associated with a slower late phase of the Vo2 off-kinetics, and as a result, the integral of Vo2 above baseline during recovery, representing the oxygen debt, is identical in all cases [values of τ(OFF)] for a given PCr decrease. Depending on τ(OFF), the muscle Vo2 on-kinetics was either equally fast or slower than the Vo2 off-kinetics in moderate exercise and always slower in heavy exercise. PCr on-kinetics was always faster than PCr off-kinetics. This study clearly demonstrates that τ(OFF) has a pronounced impact on the mutual relations between the muscle Vo2 and PCr on- and off-kinetics.

  1. 广电行业VoIP业务发展分析%Analysis of Business Development in the VoIP Broadcast and Television Industry

    Institute of Scientific and Technical Information of China (English)

    艾迪

    2016-01-01

    During a strong promotion of triple network integration , the two-way business development between broadcast and television industry and telecommunications services will be done more deeply .Under this situa-tion, we are facing enormous pressure from our existing radio , television and data services which can not com-pete with telecommunications .We should , taking advantage of this triple network integration ( with the permis-sion of policies ) , accelerate the penetration of communications services , combine our practical situation in the wire network , choose our own developmental pathway , promote a transformation from the existing business model, carry out multimedia services, and integrate video, data, voice with other services.In this paper, we analyzed the VoIP mainstream protocols and current situation , and we proposed many business ideas to build the broadcasting industry , VoIP business systems , business scenarios , business development and implementa-tion, offering a platform to be discussed by people from the same industry .%三网融合推进广电和电信业务的双向化发展,在这种形势下,广电面临巨大的压力,以现有的数字电视、数据业务无法与电信抗衡,因此广电应借助三网融合之势(政策的准入)加快对通信业务的渗透,结合有线网络的实际情况,推动现有业务模式的转变,实现视频、数据、语音等多业务融合。阐述并分析了VoIP主流协议与广电VoIP业务的现状,对VoIP业务系统的规划建设、业务场景、业务发展、实施规划等提出了思路,期望在业内展开探讨。

  2. Min-By-Min Respiratory Exchange and Oxygen Uptake Kinetics During Steady-State Exercise in Subjects of High and Low Max VO2

    Science.gov (United States)

    Weltman, Arthur; Katch, Victor

    1976-01-01

    No statistically meaningful differences in steady-state vo2 uptake for high and low max vo2 groups was indicated in this study, but a clear tendency was observed for the high max vo2 group to reach the steady-state at a faster rate. (MB)

  3. Fabrication and characterization of electrospun orthorhombic InVO4 nanofibers

    Science.gov (United States)

    Song, Lingjun; Liu, Suwen; Lu, Qifang; Zhao, Gang

    2012-02-01

    The novel orthorhombic InVO4 nanofibers have been successfully synthesized by annealing electrospun precursor fibers. Citric acid was used as a ligand for it could react with metal salts to get a transparent homogeneous precursor solution and homogeneous precursor sol for electrospining. Polyvinyl pyrrolidone (PVP, K-30) was used as a binder and a structure guide reagent because it was one kind of water-soluble polymers. It is easy to gain one-dimensional materials while the viscosity of the citrate/PVP sol was suitable. The structure, morphology and photocatalytic properties of the nanofibers were characterized by X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electron microscopy (SEM) analysis, UV-vis spectrophotometer and fluorescence spectrophotometer. The nanofibers calcined at 700 °C were orthorhombic InVO4 with a width in the range of 30-100 nm and length in micron-grade. This one-dimensional pure orthorhombic InVO4 had the higher photocatalytic activity under visible light irradiation. The photo-degradation rate of nitrobenzene aqueous solution under visible light reached 69% after 6 h. It is obvious that the orthorhombic InVO4 nanofibers have a potential application in wastewater-treatment.

  4. High-pressure powder x-ray diffraction study of EuVO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Alka B. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India); Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Física Aplicada—ICMUV, MALTA Consolider Team, Universidad de Valencia, Edificio de Investigación, C/Dr. Moliner 50, Burjassot, 46100 Valencia (Spain)

    2015-03-15

    The high-pressure structural behavior of europium orthovanadate has been studied using in-situ, synchrotron based, high-pressure x-ray powder diffraction technique. Angle-dispersive x-ray diffraction measurements were carried out at room temperature up to 34.7 GPa using a diamond-anvil cell, extending the pressure range reported in previous experiments. We confirmed the occurrence of zircon–scheelite phase transition at 6.8 GPa and the coexistence of low- and high-pressure phases up to 10.1 GPa. In addition, clear evidence of a scheelite–fregusonite transition is found at 23.4 GPa. The fergusonite structure remains stable up to 34.7 GPa, the highest pressure reached in the present measurements. A partial decomposition of EuVO{sub 4} was also observed from 8.1 to 12.8 GPa; however, this fact did not preclude the identification of the different crystal structures of EuVO{sub 4}. The crystal structures of the different phases have been Rietveld refined and their equations of state (EOS) have been determined. The results are compared with the previous experimental data and theoretical calculations. - Graphical abstract: The high-pressure structural sequence of EuVO{sub 4}. - Highlights: • EuVO{sub 4} is studied under pressure up to 35 GPa using synchrotron XRD. • The zircón–scheelite–fergusonite structural sequence is observed. • Crystal structures are refined and equations of state determined.

  5. Growth and thermophysical properties of magneto-optical crystal TbVO4

    Science.gov (United States)

    Zhu, Yangyang; Tu, Heng; Jia, Lisha; Yue, Yinchao; Zhao, Ying; Hu, Zhanggui

    2017-03-01

    TbVO4 single crystal with high transmittance has been successfully grown by Czochralski method under highly pure nitrogen atmosphere, which could reduce the loss of growth crucible. The structure of as-grown crystal was verified by X-ray powder diffraction. The refraction indices measurement showed the crystal was an optical uniaxial crystal with large birefringence. The absorption coefficient was calculated taking account into transmittance and reflection, and the results indicated TbVO4 crystal had a low absorption at wavelength range of 440-1100 nm. Thermal properties of TbVO4 crystal were also measured. The specific heat is 0.472 J g-1 K-1 at room temperature. The thermal conductivities at room temperature are 7.216 W m-1 k-1 and 10.305 W m-1 k-1along the a and c directions respectively. XPS spectra showed there were two states of V which demonstrated oxygen vacancies existed in as-grown crystal. But Verdet constant of the crystal is about 60 rad T-1 m-1, and the figure of merit at 1064 nm is 28.9°/dB at 1.2 T, which is about twice than that of TGG. All the results indicate TbVO4 crystal is a candidate to the commercial magneto-optical material at visible and near-infrared regions.

  6. Impact of VoIP and QoS on Open and Distance Learning

    Directory of Open Access Journals (Sweden)

    Sanjay JASOLA

    2006-07-01

    Full Text Available Voice over Internet Protocol (VoIP is becoming a reality in many organizations. The potential for mobility in voice over wi-fi networks will derive demand for the technology. Wireless VoIP is poised to rival VoIP as an alternative telephony tool. Internet has been used to transport data in the form of packet. In the past, Internet did not support any kind of sophisticated quality of service (QoS mechanism. Although the type of service (TOS field in the Internet protocol (IP header has been existing and has been allowing the differentiated treatment of packets, it was never really used on a large scale. The voice is sensitive to delay and jitter so bandwidth must be guaranteed while transporting it. With the extensive use of Internet for carrying voice, there is a need to add QoS functionality in it. QoS with reference to VoIP has been discussed in the paper. Limited bandwidth and network latency are the issues which need to be considered while using wireless LAN for packetized voice data. Efforts of standards like 802.11e which will take care of these issues, have also been explored. The impact of these technologies on distance education has also been explored in the paper.

  7. Diode Stack End-Pumped Nd:GdVO4 Continuous Wave Slab Laser

    Institute of Scientific and Technical Information of China (English)

    ZHANG Heng-Li; ZHANG Huai-Jin; LI Dai-Jun; WANG Ji-Yang; SHI Peng; Haas Rüdiger; LI Hong-Xia; JIANG Min-Hua; DU Keming

    2005-01-01

    @@ We report a diode stack end-pumped Nd:GdVO4 slab laser with a near-diffraction-limited beam. The output power of 45.8 W at 1064nm is obtained under the pumping power of 147W, with the optical-optical conversion efficiency of 31.2%, and the slope efficiency is 39.6%.

  8. Structural and magnetic properties of quasi-one-dimensional doped LiCuVO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Abhishek [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221 005 (India); Kumari, Poonam; Das, A. [Solid State Physics Division, Bhaba Atomic Research Center, Mumbai (India); Dwivedi, G.D. [Department of Physics, Banaras Hindu University, Varanasi 221 005 (India); Shahi, P.; Shukla, K.K. [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221 005 (India); Ghosh, A.K. [Department of Physics, Banaras Hindu University, Varanasi 221 005 (India); Nigam, A.K. [Department of CMP and MS, Tata Institute of Fundamental Research, Mumbai 400 005 (India); Chattopadhyay, K.K. [Department of Physics, Jadavpur University, Kolkata 700032 (India); Chatterjee, Sandip, E-mail: schatterji.app@iitbhu.ac.in [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221 005 (India)

    2013-12-15

    The Neutron diffraction, X-ray photoemission and Magnetic properties of Zn, Co and Mn-doped LiCuVO{sub 4} were investigated. Both with Zn and Co doping the antiferromagnetic correlation increase. On the other hand Mn-doping induces the short range ferromagnetic ordering. Neutron diffraction study does not show any phase transition down to 5 K i.e., there is no indication of long range magnetic ordering. Neutron diffraction study also indicates that with Zn, Co and Mn doping the V–O lengths are changed. Maximum change in the V–O distances is observed for Mn-doped sample. On the other hand, X-ray photoemission spectroscopic data indicates Mn doping converts some Cu{sup 2+} ions into Cu{sup 3+} ions. - Graphical abstract: LiCuVO{sub 4} is a quasi-one-dimensional spin magnet. It shows antiferromagnetic ordering. It is observed when Mn is doped in the Cu site of LiCuVO{sub 4} a short range ferromagnetic ordering occurs. - Highlights: • LiCuVO{sub 4} is an one-dimensional spin chain system. • Mn ion is doped in Cu site to induce ferromagnetism. • Doping of Mn ion changes the Cu–O–Cu bond angle which in effect induces ferromagnetism.

  9. Investigation of Terahertz Emission from BiVO4 /Au Thin Film Interface

    NARCIS (Netherlands)

    Kumar, N.; Abdi, F.F.; Trzesniewski, B.; Smith, W.A.; Planken, P.C.M.; Adam, A.J.L.

    2015-01-01

    We demonstrate emission of terahertz pulses from a BiVO4/Au thin film interface, illuminated with femtosecond laser pulses. Based on the experimental observations, we propose that the most likely cause of the THz emission is the Photo-Dember effect caused by the standing wave intensity distribution

  10. Photocharged BiVO4 photoanodes for improved solar water splitting

    NARCIS (Netherlands)

    Trześniewski, B.J.; Smith, W.A.

    2015-01-01

    Bismuth vanadate (BiVO4) is a promising semiconductor material for the production of solar fuels via photoelectrochemical water splitting, however, it suffers from substantial recombination losses that limit its performance to well below its theoretical maximum. Here we demonstrate for the first tim

  11. Blocking Probability Based Hierarchical Storage Design in VoD Systems

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we discuss the relationship between the blocking probability and the configuration of storage hierarchy in a Video on Demand (VoD) server using the queueing model we propose. With this model , the optimal configuration of the storage system can be obtained.

  12. A comparative Raman study between YbVO3 and YVO3

    NARCIS (Netherlands)

    Jandl, S.; Nugroho, A.A.; Palstra, T.T.M.

    2010-01-01

    An orbital ordering effect is observed in YbVO3 around 170 K while the crystal structure is orthorhombic (space group pnma). A monoclinic transition has been reported below TN = 104 K, while according to recent specific heat measurements, it occurs at 170 K. The crystal structure of YVO3 at 300 K is

  13. VO2 Max in Variable Type Exercise Among Well-Trained Upper Body Athletes.

    Science.gov (United States)

    Seals, Douglas R.; Mullin, John P.

    1982-01-01

    The maximal oxygen consumption (VO2 max) of well-trained upper body athletes was compared to that of untrained individuals in four types of exercise: arm cranking, legs only cycling, graded treadmill running, and combined arm cranking and leg cycling. Results of the study showed that well-trained upper body athletes attained a significantly higher…

  14. Fabrication and characterization of electrospun orthorhombic InVO{sub 4} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Song Lingjun [Shandong Provincial Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics, Shandong Polytechnic University, Jinan 250353 (China); Liu Suwen, E-mail: liusw@spu.edu.cn [Shandong Provincial Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics, Shandong Polytechnic University, Jinan 250353 (China); Lu Qifang; Zhao Gang [Shandong Provincial Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics, Shandong Polytechnic University, Jinan 250353 (China)

    2012-02-01

    The novel orthorhombic InVO{sub 4} nanofibers have been successfully synthesized by annealing electrospun precursor fibers. Citric acid was used as a ligand for it could react with metal salts to get a transparent homogeneous precursor solution and homogeneous precursor sol for electrospining. Polyvinyl pyrrolidone (PVP, K-30) was used as a binder and a structure guide reagent because it was one kind of water-soluble polymers. It is easy to gain one-dimensional materials while the viscosity of the citrate/PVP sol was suitable. The structure, morphology and photocatalytic properties of the nanofibers were characterized by X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electron microscopy (SEM) analysis, UV-vis spectrophotometer and fluorescence spectrophotometer. The nanofibers calcined at 700 Degree-Sign C were orthorhombic InVO{sub 4} with a width in the range of 30-100 nm and length in micron-grade. This one-dimensional pure orthorhombic InVO{sub 4} had the higher photocatalytic activity under visible light irradiation. The photo-degradation rate of nitrobenzene aqueous solution under visible light reached 69% after 6 h. It is obvious that the orthorhombic InVO{sub 4} nanofibers have a potential application in wastewater-treatment.

  15. Ab initio study of metal-insulator transition in VO2

    Science.gov (United States)

    Zheng, Huihuo; Wagner, Lucas K.

    2013-03-01

    The structure distortion accompanied metal-insulator transition (MIT) of vanadium dioxide (VO2) at 340K has been a matter of ongoing controversy for near four decades. It is still unclear whether the nature of this transition is due to a Peierls instability, a Mott-Hubbard transition, or other physics. Most density functional theory based methods fail to describe the nature of the electronic state in this system, further complicating theoretical description of VO2. We will report on progress in applying the first principles diffusion quantum Monte Carlo method to the electronic structure of VO2 in the metallic and insulator phases. By examining the energetic properties, one particle reduced density matrix, as well as other static correlations in the two phases of the system, we will comment on which of the two common descriptions is a closer representation of the physical reality of VO2. This work was supported by the Strategic Research Initiatives project at Illinois(HZ) and NSF DMR 12-06242 (LKW).

  16. Observatory/data centre partnerships and the VO-centric archive: The JCMT Science Archive experience

    CERN Document Server

    Economou, Frossie; Jenness, Tim; Redman, Russell O; Goliath, Sharon; Dowler, Patrick; Currie, Malcolm J; Bell, Graham S; Graves, Sarah F; Ouellette, John; Johnstone, Doug; Schade, David; Chrysostomou, Antonio

    2014-01-01

    We present, as a case study, a description of the partnership between an observatory (JCMT) and a data centre (CADC) that led to the development of the JCMT Science Archive (JSA). The JSA is a successful example of a service designed to use Virtual Observatory (VO) technologies from the start. We describe the motivation, process and lessons learned from this approach.

  17. Wave-Vector Dependence of the Jahn-Teller Interactions in TmVO4

    DEFF Research Database (Denmark)

    Kjems, Jørgen; Hayes, W.; Smith, S. H.

    1975-01-01

    The resonant Jahn-Teller coupling of the B2g acoustic phonon and the Zeeman-split ground doublet in TmVO4 has been studied by inelastic neutron scattering. Tuning of the magnetic field provides a means for investigating the wave-vector dependence of the interactions. We find that the coupling is ...

  18. Insulator-to-metal transition in (R,Ca)VO(3)

    NARCIS (Netherlands)

    Sage, M. H.; Blake, G. R.; Palstra, T. T. M.

    2008-01-01

    We have carried out a comprehensive study of the transport and thermodynamic properties of R(1-x)Ca(x)VO(3) (R=Pr, Sm, and Y), obtaining detailed information on the nature of the insulator-metal transition induced by Ca doping. The behavior of the electronic term of the specific heat as a function o

  19. Phase transition and possible metallization in CeVO{sub 4} under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Alka B., E-mail: alkagarg@barc.gov.in [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India); Shanavas, K.V. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India); Wani, B.N. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India); Sharma, Surinder M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra (India)

    2013-07-15

    Phase stability of CeVO{sub 4} under pressure has been investigated using synchrotron based angle dispersive x-ray diffraction (ADXRD), electrical resistance and first principles calculations. The results indicate that the ambient zircon structure of the compound transforms to a low symmetry monoclinic monazite phase beyond 3.8 GPa with nearly 8.6% volume discontinuity. Beyond 11 GPa, the pattern could be fitted to a similar monazite structure which is about 12.7% denser and has a much larger monoclinic beta angle. On pressure release the first monoclinic phase is recovered. The electrical resistance data show a large drop in resistance with pressure indicating substantial narrowing down of the band gap. Electronic structure calculations support these observations and suggest possible pressure induced metallization in this material. - Pressure induced structural phase transition in CeVO{sub 4} as observed by x- ray diffraction (pressure vs. volume) and possible metallization in CeVO{sub 4} through electrical resistance and first principles electronic structure calculations. - Highlights: • Structural and electrical behavior of CeVO{sub 4} under pressure studied using x-ray diffraction and electrical resistance measurements and first principles calculations. • Two successive structural transitions confirmed by experiment and theory: zircon–monazite I–monazite II. • Band gap collapse and possible metallization is indicated by electrical resistance measurements and electronic structure calculations under pressure. • Novel observation of lower bulk modulus in the high pressure phase (both by experiment and calculations) explained through structural analysis.

  20. Individualized Math Problems in Logarithms. Oregon Vo-Tech Mathematics Problem Sets.

    Science.gov (United States)

    Cosler, Norma, Ed.

    THis is one of eighteen sets of individualized mathematics problems developed by the Oregon Vo-Tech Math Project. Each of these problem packages is organized around a mathematical topic and contains problems related to diverse vocations. Solutions are provided for all problems. This volume includes problems involving logarithms, exponents, and…