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  1. 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.

  2. 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.

  3. 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

    )(7) described here. This compound crystallizes in the tetragonal space group P4(3)2(1)2 (No. 96) with a = 9.540(3) Angstrom, c = 29.551(5) Angstrom at 20 degreesC and Z = 4. It contains a distorted VO6 octahedron with a short V-O bond of 1.552(6) Angstrom, a long one of 2.276(5) Angstrom trans to this, and four...... 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....

  4. Structure, Raman and infrared spectroscopic properties of new nonlinear optical material Na3VO2B6O11

    Science.gov (United States)

    Zhang, Ji; Dou, Renqin; Zhang, Deming; Zhang, Qingli; Yin, Shaotang

    2016-08-01

    In this paper we report on the structure of Na3VO2B6O11 (NVBO) single crystals which were investigated by XRD, polarized Raman spectra in the range from 10 to 1600 cm-1 and infrared spectrum (IR) in the range from 100 to 1600 cm-1. Factor group analysis has been used to study the full vibrational representation of the crystal. More than 120 phonon modes have been obtained, which are related to Bsbnd O and Vsbnd O vibration in the trigonal planar BO3 triangle groups and tetrahedral BO4/VO4 groups. The high frequency bands located at 1300-1415 cm-1 are assigned to stretching modes of the trigonal planar BO3 groups. Moreover, intense Raman modes located at 631 cm-1 is related to BO3 bending vibration as well. The weak band at 1158 cm-1 (A1 mode) and strong band at 431 cm-1 (A1 mode) are attributed to asymmetric stretching and bending vibration mode of tetrahedral BO4 groups respectively. The vibrational band at 765-738 cm-1 in the Raman spectra of NVBO crystal maybe related to the breathing vibration of the boroxol ring consisting of two BO4 tetrahedra. In addition, we assigned the intense band 900 (A1 mode) and 831 cm-1 (B2 mode) are relative to the v1 symmetric stretching vibration of VO4 tetrahedra. And the middle intense band at 382 (A1 mode) and 385 (A2 mode) are due to Osbnd Vsbnd O vibration in VO4 tetrahedra.

  5. 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.

  6. 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

  7. 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.

  8. Theoretical studies of the optical and EPR spectra for VO^{2+} in Na_3C_6H_5O_7·2H_2O single crystal

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    Ch.-Y. Li

    2015-06-01

    Full Text Available On the basis of the perturbation formulas for a d^1 configuration ion in a tetragonal crystal field, the three optical absorption bands and electron paramagnetic resonance (EPR parameters (g factors g_i and hyperfine structure constants A_i for i = || and ⊥, respectively of VO^{2+} in Na_3C_6H_5O_7·2H_2O (TSCD single crystals were studied using the perturbation theory method. By simulating the calculated optical and EPR spectra to the observed values, local structure parameters and negative signs of the hyperfine structure constants A_i of the octahedral (VO_6^{8-} cluster in TSCD single crystal can be obtained.

  9. 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.

  10. 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

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    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

  11. 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.

  12. Piloto de gasificador downdraft operado con biomasa

    OpenAIRE

    Cuba Arroyo, Carlos Guillermo

    2011-01-01

    En este Proyecto Final de Carrera se lleva a cabo la ingeniería básica de un piloto de gasificación de biomasa, en el contexto de la producción de energía eléctrica, a partir de fuentes renovables de energía. Primeramente se realiza un estudio bibliográfico y la revisión del estado actual de la tecnología de los gasificadores para detectar a los posibles fabricantes de este sistema. A nivel comercial y en Catalunya se ha detectado a uno solo, que es la empresa Logic-energy S...

  13. Cinética do VO2 durante o exercício realizado na potência crítica em ciclistas e indivíduos não-treinados no ciclismo

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    Renato Aparecido Corrêa Caritá

    2013-06-01

    Full Text Available O objetivo foi analisar a cinética do consumo de oxigênio (VO2 na potência crítica (PC, em indivíduos com diferentes níveis de aptidão aeróbia no ciclismo. Seis ciclistas treinados (GT e sete indivíduos não-treinados (GNT realizaram os seguintes protocolos em cicloergômetro: (a progressivo até a exaustão para determinação do VO2max e sua respectiva intensidade (IVO2max; (b três testes em cargas constantes até a exaustão a 95-110%IVO2max para determinação da PC; e (c um teste em carga constante até a exaustão a 100%PC. No exercício a 100%PC, o componente lento expresso em valor absoluto (GT: 342,4±165,8 ml.min-1 vs. GNT: 571,3±170,1 ml.min-1 e relativo ao aumento do VO2 em exercício (GT: 10,0±4,6% vs. GNT: 26,6±7,3% foram menores para GT. O VO2 ao final do exercício (GT: 89,8±8,4%VO2max vs. GNT: 97,4±2,8%VO2max foi significativamente menor no grupo GT (ρ = 0,045, sendo similar ao VO2max no grupo GNT. Portanto, o nível de aptidão aeróbia pode influenciar as respostas do VO2 ao exercício em PC.

  14. 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.

  15. 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

  16. 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). PMID:26044323

  17. Potencial generador de biomasa como fuente renovable a escala local

    OpenAIRE

    PERELLÓ GUARRO, PAULA ISABEL

    2013-01-01

    Gran parte de los residuos agrícolas y forestales pueden ser utilizados como biomasa. El aprovechamiento de estos recursos como fuente de energía renovable puede ser la solución a muchos de los problemas medioambientales y económicos que existen actualmente. El objeto del presente proyecto es realizar un inventario del potencial generador de biomasa como fuente renovable a escala local. El trabajo ha sido estructurado en dos grandes partes. La primera contiene, a modo de preliminares, aquello...

  18. Cinética do consumo de oxigênio e tempo limite na vvo2max: comparação entre homens e mulheres Oxygen uptake kinetics and threshold time at the vVO2max: tomparison between men and women

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    Paulo Henrique Silva Marques de Azevedo

    2010-08-01

    Full Text Available Foi investigada a influência do gênero no tempo limite (Tlim e na cinética do VO2 durante corrida na velocidade associada ao VO2max (vVO2max em nove homens e nove mulheres, todos adultos, jovens e sedentários, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolante, sendo um teste incremental para determinar VO2max (42,66 ± 4,50 vs. 32,92 ± 6,03mL.kg-1.min-1 e vVO2max (13.2 ± 1.5 vs. 10,3 ± 2,0km.h-1, respectivamente. Um segundo teste com carga constante na vVO2max até a exaustão. O Tlim e a cinética do VO2 foram determinados. Não houve diferença significante entre homens e mulheres para constante de tempo (τ (35,76 ± 21,03 vs. 36,5 ± 6,21s, respectivamente; P = 0,29; Tlim (308 ± 84,3 vs. 282,11 ± 57,19s, respectivamente; P = 0,68, tempo para atingir o VO2max (TAVO2max (164,48 ± 96,73 vs. 167,88 ± 28,59s, respectivamente; P = 0,29, tempo para atingir o VO2max em percentual do Tlim (%Tlim (50,24 ± 16,93 vs. 62,63 ± 16,60%, respectivamente; P = 0,19, tempo mantido no VO2max (TMVO2max (144,08 ± 42,55 vs. 114,23 ± 76,96s, respectivamente; P = 0,13. Estes resultados sugerem que a cinética do VO2 e o Tlim são similares entre homens e mulheres sedentários na vVO2max.The aim of this study was to investigate the influence of gender on Tthre and VO2 response during running exercise performed at vVO2max. Therefore, eighteen untrained individuals (9 male and 9 female with normal weight and aged between 20 - 30 years (VO2max = 42.66 ± 4.50 vs 32.92 ± 6.03 mL.kg-1.min-1 and vVO2max = 13.2 ± 1.5 vs 10.3 ± 2.0 km.h-1, for male and female, respectively were assessed. Subjects performed two exercise tests on treadmill. First one was an incremental test to determine VO2max, velocity at VO2max (vVO2max and second test was performed at steady velocity - vVO2max - until exhaustion. The threshold time (Tthre and VO2 kinetics response was determined. No significant differences were observed between men

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

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    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.

  20. Aprovechamiento energético de la biomasa

    OpenAIRE

    Velo García, Enrique

    2006-01-01

    A diferencia de otras fuentes potenciales de energía como el sol, el viento o el agua, la biomasa (cualquier tipo de materia orgánica cuyo origen inmediato sea un proceso biológico, vegetal o animal) presenta una gran diversidad de vías o procesos a partir de los cuales se puede obtener energía. Si a esta diversidad le añadimos la gran variedad de la materia orgánica en cuanto a orígenes, composición y modos de recolección y tratamiento, nos encontramos con un amplio y variado esc...

  1. 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...

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Existencias y tasas de incremento neto de la biomasa y del carbono en bosques primarios y secundarios de Colombia

    OpenAIRE

    Orrego Suaza, Sergio Alonso; Del Valle Arango, Jorge Ignacio

    2002-01-01

    En 33 parcelas permanentes de 1000 m2 (0,1 ha) en bosques primarios y 77 parcelas permanentes de 500 m (0,05 ha) en bosques secundarios, para un área de muestreo de 7,15 ha, se estimaron las existencias de biomasa y del carbono almacenado en los siguientes compartimientos: biomasa aérea, necromasa, biomasa subterránea y suelo. La biomasa aérea total viva en los bosques primarios promedió 246,542 t/ha, representada 92,42% por árboles y arbustos dicotiledóneos, 5,93% en palmas (3,58% la pa...

  8. VoIP

    OpenAIRE

    Partio, Satu

    2012-01-01

    Tässä työssä kerrotaan Internetin avulla toimivasta kommunikointitekniikasta VoIP:sta. Työn tarkoitus on kertoa miten VoIP toimii ja mihin sitä käytetään. Lisäksi perehdytään tarkemmin tekniikkaan, joka siihen liittyy. Työssä kerrotaan tekniikan eduista sekä ongelmista, kuten myös tietoturvan tarpeesta ja tarpeellisista suojauksista. Puhuminen Internet-protokollan avulla on ollut jo 30 vuotta sitten mahdollista ja tekniikan kehittyessä se tuli pikkuhiljaa arkipäivän kommunikointiratkaisuk...

  9. 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.

  10. 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

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    Matías Lopez

    2014-03-01

    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

  13. MOŽE LI BIOMASA POKRENUTI ENERGIJSKU TRANZICIJU U HRVATSKOJ I JUGOISTOČNOJ EUROPI?

    OpenAIRE

    Domac, Julije; Risović, Stjepan; Šegon, Velimir; Pentek, Tibor; Šafran, Branimir; Papa, Ivica

    2015-01-01

    Šumska biomasa predstavlja važan izvor energije, čijem bi se korištenju u budućnosti trebalo posvetiti znatno više pozornosti. Biomasa u svojim tradicionalnim oblicima je i dalje vrlo važan izvor energije u većini zemalje Jugoistočne Europe, te će u doglednoj budućnosti i dalje biti tako. Međutim, sve se više koristi ne samo za proizvodnju toplinske energije, već za proizvodnju električne i rashladne energije, i to se smatra kao važan dio energijske tranzicije koja je obećavajući model ...

  14. Accessing the VO with Python

    Science.gov (United States)

    Plante, R.; Fitzpatrick, M.; Graham, M.; Tody, D.; Young, W.

    2014-05-01

    We introduce two products for accessing the VO from Python: PyVO and VOClient. PyVO is built on the widely-used Astropy package and is well suited for integrating automated access to astronomical data into highly customizable scripts and applications for data analysis in Python. VOClient is built on a collection of C-libraries and is well suited for integrating with multi-language analysis packages. It also provides a framework for integrating legacy software into the Python environment. In this demo, we will run through several examples demonstrate basic data discovery and retrieval of data. This includes finding archives containing data of interest (VO registry), retrieving datasets (SIA, SSA), and exploring (Cone Search, SLAP). VOClient features some extended capabilities including the ability to communicate to other desktop applications from a script using the SAMP protocol.

  15. 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.

  16. 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

  17. VoIP security - attacks and solutions

    OpenAIRE

    Phithakkitnukoon, Santi; Dantu, Ram; Baatarjava, Enkh-Amgalan

    2008-01-01

    Voice over IP (VoIP) technology is being extensively and rapidly deployed. Flexibility and cost efficiency are the key factors luring enterprises to transition to VoIP. Some security problems may surface with the widespread deployment of VoIP. This article presents an overview of VoIP systems and its security issues. First, we briefly describe basic VoIP architecture and its fundamental differences compared to PSTN. Next, basic VoIP protocols used for signaling and media transport, as well as...

  18. 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.

  19. VoIP over WLAN

    OpenAIRE

    Nikkari, Joni

    2007-01-01

    Tässä opinnäytetyössä tutkitaan VoIP over WLAN -tekniikan mahdollisuuksia nykyaikaisessa käyttöympäristössä, sekä yritysmaailman että kotikäyttäjän näkökulmasta. Toimiakseen VoWLAN tarvitsee kaksi eri tekniikkaa: langattoman lähiverkon sekä WLAN-puhelimen, joka perustuu VoIP-tekniikkaan.; WLAN:ssa tietoliikenne kulkee normaalin kaapeloinnin sijasta radiotaajuuksia käyttämällä. Standardina toimii IEEE 802.11, joka määrittelee WLAN-verkkojen toiminnan. Standardia on kehitetty jatkuvasti, ja si...

  20. VO2(B conversion to VO2(A and VO2(M and their oxidation resistance and optical switching properties

    Directory of Open Access Journals (Sweden)

    Zhang Yifu

    2016-03-01

    Full Text Available Vanadium dioxide VO2 has been paid in recent years increasing attention because of its various applications, however, its oxidation resistance properties in air atmosphere have rarely been reported. Herein, VO2(B nanobelts were transformed into VO2(A and VO2(M nanobelts by hydrothermal route and calcination treatment, respectively. Then, we comparatively studied the oxidation resistance properties of VO2(B, VO2(A and VO2(M nanobelts in air atmosphere by thermo-gravimetric analysis and differential thermal analysis (TGA/DTA. It was found that the nanobelts had good thermal stability and oxidation resistance below 341 °C, 408 °C and 465 °C in air, respectively, indicating that they were stable in air at room temperature. The fierce oxidation of the nanobelts occurred at 426, 507 and 645 °C, respectively. The results showed that the VO2(M nanobelts had the best thermal stability and oxidation resistance among the others. Furthermore, the phase transition temperatures and optical switching properties of VO2(A and VO2(M were studied by differential scanning calorimetry (DSC and variable temperature infrared spectra. It was found that the VO2(A and VO2(M nanobelts had outstanding thermochromic character and optical switching properties.

  1. Estudio: cantidad y costes de aprovechamiento de la biomasa existente en el T.M. de Carcaixent y el estudio de viabilidad para la ejecución de una Planta de Biomasa

    OpenAIRE

    MARTÍNEZ ABARCA, MARÍA BELINDA

    2013-01-01

    El objetivo general que se plantea en el presente trabajo es la evaluación de la disponibilidad de recursos y determinar la cantidad de la biomasa extraíble procedentes de las plantaciones de naranjos y otros cultivos existentes en el Término Municipal de Carcaixent. Se pretende estudiar la viabilidad económica de la extracción de biomasa de zonas forestales, agrícolas y zonas verdes del municipio mediante tratamientos selvícolas adecuados. El aprovechamiento de estos res...

  2. Producción de ácido láctico a partir de biomasa de origen vegetal

    OpenAIRE

    Fernández Díez, Laura

    2014-01-01

    Se va a estudiar la conversión a ácido láctico de distintos tipos de biomasa, siendo necesario que la biomasa presente fructosa en su composición. Las biomasas que se utilizarán serán: sacarosa, melaza de caña, melaza de remolacha e inulina. Para ello se empleará una planta piloto con unas condiciones de trabajo de 400 ºC y 25 MPa, con un tiempo de residencia de 3 segundos, utilizando un catalizador con grupos hidroxilo. Una vez efectuada la reacción, los productos se llevarán a una cámara fl...

  3. 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

  4. 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.

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

    OpenAIRE

    Saldarriaga Elorza, Juan Fernando

    2015-01-01

    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 ...

  6. Factores de expansión de biomasa en comunidades forestales templadas del norte de Durango, México

    OpenAIRE

    Flor María Silva-Arredondo; José de Jesús Návar-Cháidez

    2010-01-01

    La biomasa forestal, por lo general, es cuantificada en kilogramos por árbol o en toneladas por hectárea de peso verde o de peso seco. En un bosque es un elemento ambiental clave para calcular los montos de carbono que puedan liberarse a la atmósfera o bien fijarse, cuando estos ecosistemas son manejados para mitigar los gases de efecto invernadero. El presente trabajo se llevó a cabo en el norte del estado de Durango, México, con el objetivo de estimar la biomasa arbórea aérea (M) y los fact...

  7. Speaker Recognition in the VoIP Environment

    OpenAIRE

    Remeš, Jan

    2014-01-01

    Tato práce popisuje použití systémů pro rozpoznávání mluvčího v~prostředí VoIP, úspěšnost systému a přístupy k jejímu zlepšení. Popisuje architekturu těchto systémů, metriky pro vyhodnocení jejich úspěšnosti a klíčové komponenty VoIP z hlediska rozpoznávání mluvčího. Je zde popsáno vytvoření simulace VoIP prostředí, úspěšnost systému je vyhodnocena na datech pocházejících z různých druhů VoIP prostředí a výsledky jsou demostrovány. Adaptace a kalibrace systému je provedena a jejich přínosy zh...

  8. 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

  9. ESTIMACIÓN DE LA BIOMASA FORESTAL PARA LAS ESPECIES QUERCUS ROTUNDIFOLIA Y QUERCUS SUBER BASADA EN IMÁGENES DEL SATÉLITE QUICKBIRD

    OpenAIRE

    Sousa, Adélia; Marques da Silva, José; Gonçalves, Ana Cristina; Mesquita, Paulo; Silva, Luis; Baptista, F.J.

    2013-01-01

    para una buena gestión. Actualmente las técnicas de inventario y monitoreo de biomasa forestal son usualmente lentas, muy trabajosas y de elevado coste, verificándose así la necesidad de desarrollar otras técnicas, que sean fiables y con costes relativamente reducidos. El objetivo de este estudio es desarrollar una metodología para estimar la biomasa forestal de las especies Quercus rotundifolia y Quercus suber basada en imágenes del satélite QuickBird. La estimación de la biomasa...

  10. Produccion de Biomasa de Scenedesmus Obliquus en diferentes medios de cultivo.

    Directory of Open Access Journals (Sweden)

    V. Martínez

    2005-01-01

    Full Text Available Los nutrientes son factores fundamentales que afectan el rendimiento de los cultivos de microalgas, de ahí la importancia de llevar a cabo estudios a escala de laboratorio con cepas de interés científico y comercial. El objetivo del trabajo fue investigar la producción de biomasa de Scenedesmus obliquus en diferentes medios de cultivo. Se utilizaron dos reactores tipo columnas de 2 L de capacidad empleando medio Extracto de Suelo, y medio Albañal Sintético respectivamente, a los cuales se les adicionó el inóculo del cultivo (1%, en la fase logarítmica de crecimiento. Para mantener agitado y homogéneo el sistema, se suministró aire a razón de 100 L/h, que fue medido con un regulador de flujo y se colocaron en un local cuya temperatura media era de 29,7 o C. Los reactores trabajaron en modo discontinuo (batch. Se mantuvieron con un régimen de luz/oscuridad de 8/16 horas durante 18 días. Para seguir el comportamiento del cultivo se determinó la Densidad óptica, la clorofila a, los sólidos suspendidos volátiles, se midió el pH y la producción de biomasa en el sistema. La velocidad de crecimiento específico fue ¿ = 0,16 d-1 para el cultivo en el medio Agar extracto de suelo y ¿ = 0,33 d-1 para el cultivo en medio Albañal sintético. El tiempo de duplicación fue de 4,33 d'-1 para el cultivo en medio AES y 2,10 d-1 para el medio de Albañal Sintético. Se alcanzaron los valores más altos en la producción de biomasa en el medio Albañal, lo que demostró un mejor desarrollo de la microalga investigada en este medio.

  11. VoIP Technology: Security Issues Analysis

    OpenAIRE

    Lazzez, Amor

    2013-01-01

    Voice over IP (VoIP) is the technology allowing voice and multimedia transmissions as data packets over a private or a public IP network. Thanks to the benefits that it may provide, the VoIP technology is increasingly attracting attention and interest in the industry. Actually, VoIP allows significant benefits for customers and communication services providers such as cost savings, rich media service, phone and service portability, mobility, and the integration with other applications. Nevert...

  12. Investigation of VoIP and implementation

    OpenAIRE

    Ede, Aghedo

    2011-01-01

    Voice over Internet Protocol (VoIP) is the technology used to transmit conversations digitally over the Internet. VoIP is being adopted globally and changing the landscape of telecommunications for businesses and consumers. This thesis describes the investigation of VoIP and how it compares to traditional phone systems, voice characteristics, implementation challenges, digital voice process, testing and result, the standards organizations promoting the technology, and what this means for us ...

  13. Respirómetro con biomasa fija sobre soporte permeable a gases.

    OpenAIRE

    Tejero Monzón, Juan Ignacio; Osa Olaizola, Juan José; Gómez Fuentes, Claudio

    1997-01-01

    Dispositivo para la realización de medidas respirométricas de líquidos que contengan materia orgánica, caracterizado por el empleo de membranas permeables a gases como soporte para la biomasa y como parte del sistema de oxigenación. La oxigenación se produce a través de la membrana directamente a la biopelícula adherida a la misma. La determinación de la tasa de respiración se realiza midiendo la cantidad de oxígeno que se transfiere a través de la membrana y corrigiendo el efecto del oxígeno...

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

    OpenAIRE

    Julián Rodrigo Quintero González; Laura Estefanía Quintero González

    2015-01-01

    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 posibil...

  15. VoIP网络浅析

    Institute of Scientific and Technical Information of China (English)

    蔡云刚

    2009-01-01

    IP网上语音(VoIP)网络已逐步得到了广泛地应用,但随之而来的安全性问题也越来越突出,本文介绍了VoIP网络系统构成、工作原理及其主要的协议体系结构,对VoIP网络存在的安全隐患进行了分析,并给出了加强VoIP网络安全性的建议.

  16. Security in VoIP

    OpenAIRE

    Floriana GEREA

    2012-01-01

    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 ot...

  17. Polynuclear complexes with bridging pyrophosphate ligands: synthesis and characterisation of {[(bipy)Cu(H2O)(mu-P2O7)Na2(H2O)6] x 4H2O}, {[(bipy)Zn-(H2O)(mu-P2O7)Zn(bipy)]2 x 14H2O} and {[(bipy)(VO)2]2(mu-P2O7)] x 5H2O}.

    Science.gov (United States)

    Doyle, Robert P; Nieuwenhuyzen, Mark; Kruger, Paul E

    2005-12-01

    The reaction in water of M(II) ions (M = Cu, 1; Zn, 2; VO, 3) with 2,2'-bipyridine (bipy) followed by Na4P2O7 leads to the formation of three new complexes which feature the pyrophosphate anion, P2O7(4-), as a bridging ligand. Single crystal X-ray diffraction revealed 1 to be {[(bipy)Cu(H2O)(micro-P2O7)Na2(H2O)6] x 4H2O}, and 2 as a tetranuclear Zn(II) complex, {[(bipy)Zn(H2O)(micro-P2O7)Zn(bipy)]2 x 14H2O}. The structure of 1 consists of a mononuclear [(bipy)Cu(H2O)(P2O7)]2- unit that links via a pyrophosphate bridge to two Na atoms. The hydrated six-coordinate Na atoms themselves join together through bridging water molecules to generate a 2D Na-water sheet. The structure of 2 consists of a tetranuclear Zn(II) cluster (dimer-of-dimers) with two pyrophosphate ligands bridging between four metal centres. Adjacent clusters interact through face-to-face pi-pi interactions via the bipy ligands to yield a 2D sheet. Adjacent sheets pack in register to create channels, which are filled by the water molecules of crystallisation. An intricate 2D H-bonded water network separates adjacent sheets and encapsulates the tetranuclear clusters. Aspects of the pyrophosphate coordination modes in 1 and 2 are of structural relevance to those found within the inorganic pyrophosphatases. Compound 3, {[(bipy)(VO)2]2(micro-P2O7)] x 5H2O}, was isolated as an insoluble lime-green powder. Its dinuclear structure was elucidated from elemental and thermal analysis, magnetic susceptibility measurement and IR spectroscopy. The latter displayed characteristic bridging pyrophosphate and signature V=O stretches, which were corroborated by contrast to the IR spectra of 1 and 2 and through comparison with those found in the structurally characterised dinuclear complex, {[(bipy)Cu(H2O)]2(micro-P2O7) x 7H2O}, 4. PMID:16471055

  18. 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

  19. Technology and Product of VoIP%VoIP技术与产品

    Institute of Scientific and Technical Information of China (English)

    张瑞斌; 梁柏青

    2000-01-01

    介绍了VoIP技术及VoIP系统相关技术、协议标准,突出阐述了IP网络电话的产品类型、产品功能及应用,提出对VoIP技术和产品发展的几点看法,介绍了信令网关在VoIP网络中的应用及作用,指出企业内部的VoIP应用的情况.

  20. VoIP技术与校园网%VoIP Technology and School Network

    Institute of Scientific and Technical Information of China (English)

    戴国梁; 程线

    2005-01-01

    VoIP技术的先进技术模式出发,分析了教育城域网VoIP应用和VoIP语音系统的现存问题,探究了VoIP技术的出现对现有的校园网络的影响,阐述了VoIP技术在校园网络体系中技术功能强大,兼容性好,服务灵活的特性,并提出了教育城域网连接方案.

  1. VoIP to the Rescue

    Science.gov (United States)

    Milner, Jacob

    2005-01-01

    Voice over Internet Protocol (VoIP) is everywhere. The technology lets users make and receive phone calls over the Internet, transporting voice traffic alongside data traffic such as instant messages (IMs) and e-mail. While the number of consumer customers using VoIP increases every week, the technology is finding its way into K-12 education as…

  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. 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.

  4. 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

  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. VoIP in Jabber Client

    OpenAIRE

    Kulička, Vojtěch

    2011-01-01

    Práce se zabývá možnostmi implementace VoIP do existujícího XMPP programu se sdílenou tabulí. Analyzuje možnosti využití současných technologií pro podporu VoIP.  Cílem je nahrazení stávajících komunikačních knihoven klienta za telepathy. Dále také přidání VoIP.

  7. 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.

  8. 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。

  9. Single crystalline VO2 nanosheets: A cathode material for sodium-ion batteries with high rate cycling performance

    Science.gov (United States)

    Wang, Wei; Jiang, Bo; Hu, Liwen; Lin, Zheshuai; Hou, Jungang; Jiao, Shuqiang

    2014-03-01

    In recent years, with the growing demands for large-scale applications of rechargeable batteries, the eco-friendly sodium-ion batteries with low price and high charge-discharge rates have attracted much attention. In this work, using a simple hydrothermal process, we successfully synthesize single crystalline VO2 parallel ultrathin nanosheets for the cathode material in sodium-ion batteries. Combined the XRD, XPS, electrochemical measurements with the first-principles simulations, the charge-discharge performance and the mechanism of Na insertion and extraction into/from the VO2 structure have systematically studied. The results reveal that the NaxVO2 products possess semiconductor properties and the interlayer distance almost keeps constant during charge and discharge process, which is beneficial to the transmission of Na ions. The charge and discharge process occurs between Na0.3VO2 and NaVO2. Even at a large current density of 500 mA g-1, the discharge capacity can still keep at 108 mAh g-1. As a cathode material for sodium-ion batteries, the results are outstanding and provide a possibility of large-scale applications for rechargeable sodium-ion batteries.

  10. 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.

  11. 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.

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

    OpenAIRE

    TALAL AL-KHAROBI; Mohmmed Abduallah Al-Mehdhar

    2012-01-01

    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 ...

  14. VoIP technology comes of age.

    Science.gov (United States)

    2008-04-01

    Cabling specialist Connectix examines the growing potential for healthcare sector use of VoIP technology and highlights the importance of correct cabling infrastructure as a carrier of both voice and high-speed data traffic. PMID:18494421

  15. Security Issues in VoIP Based on H.323

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-feng; DENG Ze; LI Xing

    2004-01-01

    We first discusses some threats to VoIP system and H.323 architectures designed for VoIP communications on security point of view. Continues with presenting security requirements of VoIP, and explaining the essential security constraints surrounding a successful VoIP deployment. Finally, suggests some strategies to implement the security and encryption functions of VoIP system based on H.323.

  16. Integrating Existing Software Toolkits into VO System

    OpenAIRE

    Cui, Chenzhou; Zhao, Yongheng; Wang, Xiaoqian; Sang, Jian; Luo, Ze

    2004-01-01

    Virtual Observatory (VO) is a collection of interoperating data archives and software tools. Taking advantages of the latest information technologies, it aims to provide a data-intensively online research environment for astronomers all around the world. A large number of high-qualified astronomical software packages and libraries are powerful and easy of use, and have been widely used by astronomers for many years. Integrating those toolkits into the VO system is a necessary and important ta...

  17. Magnetic Irreversibility in VO2/Ni Bilayers

    Science.gov (United States)

    de La Venta, Jose; Lauzier, Josh; Sutton, Logan

    The temperature dependence of the coercivity and magnetization of VO2/Ni bilayers was studied. VO2 exhibits a well-known Structural Phase Transition (SPT) at 330-340 K, from a low temperature monoclinic (M) to a high temperature rutile (R) structure. The SPT of VO2 induces an inverse magnetoelastic effect that strongly modifies the coercivity and magnetization of the Ni films. In addition, the growth conditions allow tuning of the magnetic properties. Ni films deposited on top of VO2 (M) show an irreversible change in the coercivity after the first cycle through the high temperature phase, with a corresponding change in the surface morphology of VO2. On the other hand, the Ni films grown on top of VO2 (R) do not show this irreversibility. These results indicate that properties of magnetic films are strongly affected by the strain induced by materials that undergo SPT and that it is possible to control the magnetic properties by tuning the growth conditions.

  18. 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.

  19. 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.

  20. El potencial de la biomasa en España. Condicionantes para su desarrollo y viabilidad económica

    OpenAIRE

    Gregorio, Marga de

    2012-01-01

    El sector español de la biomasa es tremendamente amplio y heterogéneo, al ser un sector muy vinculado a otros sectores productivos profundamente arraigados en nuestro país, como son el agrícola, el forestal y el ganadero. La cercanía a estos sectores, y en general al medio rural, lo convierten en un sector que despierta gran interés entre los agricultores, los propietarios forestales, los ganaderos y entre los empresarios que gestionan explotaciones agroindustriales, agroganaderas, al...

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

    OpenAIRE

    Carlos Francisco González Hernández; Manuel de Jesús Sol Hernández; Miguel Ángel Franco Nava

    2014-01-01

    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. ...

  2. Estudio de enzimas oxidorreductasas en la transformación de biomasa lignocelulósica en biocombustibles

    OpenAIRE

    Moreno García, Antonio David

    2013-01-01

    NOTA 520 8 La transformación de la biomasa lignocelulósica mediante procesos bioquímicos consta de una etapa de pretratamiento, una etapa de hidrólisis enzimática y una etapa de fermentación. El material pretratado completo (MPC) normalmente es filtrado y lavado para obtener la fracción de residuos sólidos insolubles (RSI) rica en celulosa y lignina. Esta lignina residual supone una barrera para la hidrólisis enzimática de la celulosa y un proceso de deslignificación podría mejorar los proc...

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

    OpenAIRE

    T. E. Ruiz; Castillo, E.; J. Alonso; G. Febles

    2006-01-01

    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 bio...

  4. Densidad y biomasa de Pterois volitans/miles (Teleostei: Scorpaenidae) en arrecifes del litoral oeste de La Habana, Cuba

    OpenAIRE

    García-Rodríguez, Alain; Chevalier Monteagudo, Pedro P.; Cabrera Sansón, Erlán; Caballero Aragón, Hansel; Luis Hernández López, Jorge

    2015-01-01

    El pez león (Pterois volitans/miles) es la primera especie (s) de pez arrecifal del Indo- Pacífico que invade el Atl{ntico Occidental, constituyendo una de las invasiones de peces marinos m{s r{pida de la historia. El objetivo fue determinar la densidad y biomasa de las poblaciones del pez león y sus posibles variaciones temporales y espaciales en arrecifes del oeste de La Habana, Cuba. Los muestreos fueron realizados mediante censos visuales con buceo autónomo en los períodos ...

  5. Aplicación integral en construcción de materiales eco-eficientes con incorporación de cenizas de biomasa

    OpenAIRE

    Jiménez Serrano, Ivelisse

    2016-01-01

    El empleo de biomasa como combustible para la generación de bio-energía va en aumento en la actualidad, debido a su impacto medioambiental nulo en cuanto a las emisiones de CO2. Por lo tanto la generación de cenizas de biomasa, residuo de la producción de esta energía, constituye un problema medioambiental con un claro impacto social y económico. Este tipo de ceniza tiene contenidos en óxidos que la hacen atractiva para su empleo como sustituto parcial del cemento Portland, lo cual proporcion...

  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. Efecto del pretatamiento de biomasa procedente de un hábitat eutrofizado sobre la bioadsorción de metales pesados

    OpenAIRE

    Lezcano Valverde, José María

    2008-01-01

    Una vez analizado, en líneas generales, el estado actual de la investigación realizada en el área de bioadsorción, queda patente la existencia de diversos aspectos menos estudiados tales como, por ejemplo, la utilización de biomasas heterogéneas en lugar de biomasas uniespecíficas.. Otros aspectos relativamente poco estudiados, según la bibliografía, han sido los sistemas multimetálicos a pesar de ser lo más habitual en efluentes industriales. Por último, en el caso del pretratamiento de la b...

  8. Modelos para la estimación del carbono en la biomasa de los sistemas forestales : influencia de la selvicultura en los socks de carbono

    OpenAIRE

    Ruiz-Peinado Gertrudix, Ricardo

    2013-01-01

    Es ampliamente conocido y reconocido que los bosques tienen un papel fundamental en la mitigación del cambio climático. Funcionan como almacenes de carbono fijando el carbono que captan de la atmósfera en sus estructuras, conformando biomasa viva. El carbono de esta biomasa, una vez que esta muere, puede pasar de nuevo a la atmósfera o puede seguir almacenado durante años formando parte de productos forestales (madera, corcho, etc.) o en el suelo tras la descomposición de la materia orgánica....

  9. El proceso de quema de biomasa de bosque tropical y de sabanas en la Amazonia Brasilera : experiencias de monitoreo con datos ópticos y de microondas

    OpenAIRE

    dos Santos, Joáo Roberto; Pardi Lacruz, María Silvia; Spinelli de Araujo, Luciana; Magalháes Xaud, Harón Abrahim

    1998-01-01

    El presente trabajo muestra experiencias en el uso de imágenes multisensores (TM/Landsat y JERS-1) para el inventario de biomasa de formaciones forestales y de sabanas, y como herramienta del monitoreo de las quemas que ocurren en estos tipos de vegetación en la región Amazónica. Se describen procedimientos metodológicos de adquisición de datos de biomasa vegetal de porte forestal y de las sabanas. Estos datos son relacionados con las informaciones espectro-texturales de las imágenes de...

  10. Análisis de la viabilidad de una peletizadora de biomasa forestal en la Reserva de la Biosfera de la Sierra del Rincón (Madrid)

    OpenAIRE

    Romero-Calcerrada, Raúl; Manzano-Chicote, Ignacio; Novillo, Carlos J.

    2014-01-01

    En este trabajo se plantea como objetivo el análisis del aprovechamiento de biomasa forestal en la las Reservas de Biosfera (RB) de la Sierra del Rincón (Comunidad de Madrid), determinando la biomasa forestal disponible como materia prima para una planta peletizadora en La Hiruela bajo cuatro escenarios y aplicado sobre distintas áreas de aprovechamiento. Esta metodología se fundamenta en datos del Tercer Inventario Forestal Nacional, el mapa forestal, la Zonificación de la RB, un Modelo Digi...

  11. VoIP:n tietoturva ja soveltuvuus julkishallintoon

    OpenAIRE

    Viitala, Juha

    2007-01-01

    VoIP eli internet-puhelut on nykyaikainen puhelintekniikka. VoIP:n avulla voidaan siirtää ääntä ja videokuvaa reaaliaikaisesti internetin välityksellä. VoIP perustuu yleiseen ja hyväksi todettuun IP-tekniikkaan, jossa tieto kulkee verkossa IP-paketteina. VoIP on yleistymässä nopeasti niin yrityksissä, julkishallinnossa kuin kuluttajienkin keskuudessa. VoIP-tekniikan etuina ovat sen edullisuus ja joustavuus. VoIP:n käytön yleistymisen myötä sen tietoturva on noussut puheenaiheeksi. Koska int...

  12. 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.

  13. 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.

  14. VoIP - new way of communication

    OpenAIRE

    Černý, Jan

    2011-01-01

    The subject of this bachelor thesis is IP telephony as a new way of communication capable of replacing the current analogue telephony adequately. The aim is to introduce the VoIP environment, principles and also its real use. The thesis is divided into three parts. The first part is focused on the above mentioned environment as well as on used layers and protocols of OSI and TCP/IP models. The second part looks into the VoIP technology itself, from voice digitalization to voice transfer using...

  15. Understanding VoIP from Backbone Measurements

    OpenAIRE

    Birke, Robert Rene' Maria; Petracca, Michele; Mellia, Marco

    2007-01-01

    VoIP has widely been addressed as the technology that will change the Telecommunication model opening the path for convergence. Still today this revolution is far from being complete, since the majority of telephone calls are originated by circuit-oriented networks. In this paper for the first time to the best of our knowledge, we present a large dataset of measurements collected from the FastWeb backbone, which is one of the first worldwide Telecom operator to offer VoIP and high-speed data ...

  16. Synthesis and Electrochemical Properties of Nano-VO2 (B).

    Science.gov (United States)

    Yang, Yun; Lu, Yong; Wang, Wei; Feng, Chuanqi; Yang, Shuijin

    2016-03-01

    The nano-VO2 (B) has been self-assembly synthesized by hydrothermal method using different templates, which may give them some interesting properties. The as-prepared samples were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the samples were investigated. The results show that the hexadecyltrimethyl ammonium bromide (CTAB) (soft template) was used to obtain the VO2 (B1) nanobelts. The flake graphite (hard template) was taken to get the VO2 (B2) nanosheets. The VO2 (B1) nanobelts have higher initial capacity to compare with VO2 (B2). But the VO2 (B2) nanosheets showed better cycling performance than that of VO2 (B1) nanobelts. The nano VO2 (B2) is a promising anode material for lithium ion battery application. PMID:27455666

  17. 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.)

  18. 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.

  19. Euro-VO-Coordination of virtual observatory activities in Europe

    Science.gov (United States)

    Genova, Françoise; Allen, Mark G.; Arviset, Christophe; Lawrence, Andy; Pasian, Fabio; Solano, Enrique; Wambsganss, Joachim

    2015-06-01

    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 summarises 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 initiatives, documenting the added-value of European coordination. Finally, the current status and next steps of Euro-VO are briefly addressed.

  20. How To: Be VoIP-Savvy

    Science.gov (United States)

    Branzburg, Jeffrey

    2005-01-01

    Cablevision, Comcast, Verizon, and many other high-speed broadband Internet providers are now also offering telephone services through "Voice over Internet Protocol" (VoIP). This technology sends ordinary telephone calls over the Internet rather than over telephone lines. While impractical without the use of a broadband Internet connection, with…

  1. Is VoIP Worth It?

    Science.gov (United States)

    Schaffhauser, Dian

    2008-01-01

    School districts have by and large had great results implementing VoIP, which has become the conduit for delivering expanded functionality, achieving greater internal control, and gaining freedom from onerous monthly phone bills. But demonstrating a financial return on what is a substantial investment can be an elusive effort. The goal of…

  2. VoIP in a Campus Environment

    Science.gov (United States)

    Young, Dan

    2005-01-01

    Internet Protocol (IP) Telephony, or voice-over IP (VoIP), has proved to be a wise decision for many organizations. This technology crosses the boundaries of public and private networks, enterprise and residential markets, voice and data technologies, as well as local and long-distance services. The convergence of voice and data into a single,…

  3. Estimación de biomasa residual mediante imágenes de satélite y trabajo de campo: Modelización del potencial energético de los bosques turolenses

    OpenAIRE

    García Martín, Alberto; Riva Fernández, Juan de la; Royo Herrer, Francisco Javier

    2010-01-01

    La utilización de biomasa residual forestal como recurso energético está por debajo de los objetivos fijados en materia de energías renovables dada la inexistencia de una metodología para evaluar la cantidad de residuos en una región. Esta investigación desarrolla una metodología para estimar esta biomasa a escala regional a partir del uso de teledetección y SIG. Para ello, se calcula la biomasa residual (tons/ha) en las parcelas del Segundo Inventario Forestal Nacional de la provincia de Ter...

  4. 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.

  5. 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.

  6. 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.

  7. Effect of buffer layer on thermochromic performances of VO2 films fabricated by magnetron sputtering

    Science.gov (United States)

    Zhu, Benqin; Tao, Haizheng; Zhao, Xiujian

    2016-03-01

    As a well-developed industrial fabricating method, magnetron sputtering technique has its distinct advantages for the large-scale production. In order to investigate the effect of buffer layer on the formation and thermochromic performances of VO2 films, using RF magnetron sputtering method, we fabricated three kinds of buffer layers SiO2, TiO2 and SnO2 on soda lime float-glass. Then according to the reactive DC magnetron sputtering method, VO2 films were deposited. Due to the restriction of heat treatment temperature when using soda lime float-glass as substrates, dense rutile phase TiO2 cannot be formed, leading to the formation of vanadium oxide compounds containing Na ions. When using SnO2 as buffer layer, we found that relatively high pure VO2 can be deposited more easily. In addition, compared with the effect of SiO2 buffer layer, we observed an enhanced visible transparency, a decreased infrared emissivity, which should be mainly originated from the modified morphology and/or the hetero-structured VO2/SnO2 interface.

  8. 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.

  9. Using VoIP to compete.

    Science.gov (United States)

    Werbach, Kevin

    2005-09-01

    Internet telephony, or VoIP, is rapidly replacing the conventional kind. This year, for the first time, U.S. companies bought more new Internet-phone connections than standard lines. The major driver behind this change is cost. But VoIP isn't just a new technology for making old-fashioned calls cheaper, says consultant Kevin Werbach. It is fundamentally changing how companies use voice communications. What makes VoIP so powerful is that it turns voice into digital data packets that can be stored, copied, combined with other data, and distributed to virtually any device that connects to the Internet. And it makes it simple to provide all the functionality of a corporate phone-call features, directories, security-to anyone anywhere there's broadband access. That fosters new kinds of businesses such as virtual call centers, where widely dispersed agents work at all hours from their homes. The most successful early adopters, says Werbach, will focus more on achieving business objectives than on saving money. They will also consider how to push VoIP capabilities out to the extended organization, making use of everyone as a resource. Deployment may be incremental, but companies should be thinking about where VoIP could take them. Executives should ask what they could do if, on demand, they could bring all their employees, customers, suppliers, and partners together in a virtual room, with shared access to every modern communications and computing channel. They should take a fresh look at their business processes to find points at which richer and more customizable communications could eliminate bottlenecks and enhance quality. The important dividing line won't be between those who deploy Vol P and those who don't, or even between early adopters and laggards. It will be between those who see Vol P as just a new way to do the same old things and those who use itto rethink their entire businesses. PMID:16171218

  10. 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.

  11. 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

  12. 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...

  13. MGCP在VoIP中的应用及优势

    Institute of Scientific and Technical Information of China (English)

    胡冯梅; 张春红; 于斌

    2005-01-01

    VoIP是IP网络之上的语音传输技术,基于软交换的VoIP不仅提供语音业务,还通过各种协议和设备给用户提供综合的数据业务.本文简单介绍了VoIP的主要协议之一媒体网关控制协议MGCP、当前广泛采用H.323的VoIP体系结构,以及采用MGCP的VoIP体系结构,详细分析了采用MGCP的VoIP体系结构较之H.323的VoIP体系所具有的优势.

  14. Electrical oscillation in Pt/VO2 bilayer strips

    International Nuclear Information System (INIS)

    We report on the observation of stable electrical oscillation in Pt/vanadium dioxide (VO2) bilayer strips, in which the Pt overlayer serves the dual purposes of heating up the VO2 and weakening the electric field in the VO2 layer. Systematic measurements in an ultrahigh vacuum nanoprobe system show that the oscillation frequency increases with the bias current and/or with decreasing device dimension. In contrast to most VO2-based oscillators reported to date, which are electrically triggered, current-induced Joule heating in the Pt overlayer is found to play a dominant role in the generation of oscillation in Pt/VO2 bilayers. A simple model involving thermally triggered transition of VO2 on a heat sink is able to account for the experimental observations. The results in this work provide an alternative view of the triggering mechanism in VO2-based oscillators

  15. Analysis and Test of VoIP Voice Quality%VoIP话音质量分析与测试

    Institute of Scientific and Technical Information of China (English)

    刘石峰; 孙悦

    2008-01-01

    随着VoIP发展的日趋成熟,VoIP单凭粗放低价进行市场竞争日趋艰难,更多人把关注点投向VolP服务质量.首先从VoIP的传输层面和业务层面分析影响VoIP话音质量的主要因素,然后提出相应的应对方法,最后提出测试与评估VoIP话音质量的指标体系以及测试方法.

  16. VoIP原理介绍及组网技术%Theory and Networking Technique of VoIP

    Institute of Scientific and Technical Information of China (English)

    黄旭升; 黄旭光

    2004-01-01

    主要介绍 VoIP的原理,以及相关的 H.323协议族,重点阐述了 VoIP的呼叫过程及 VoIP的网络规划,同时对 VoIP的服务及话音质量的控制及实现作出进一步的论述.最后结合相关产品说明 VoIP具体实现的方法.

  17. 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

  18. Modular VO oriented Java EE service deployer

    Science.gov (United States)

    Molinaro, Marco; Cepparo, Francesco; De Marco, Marco; Knapic, Cristina; Apollo, Pietro; Smareglia, Riccardo

    2014-07-01

    The International Virtual Observatory Alliance (IVOA) has produced many standards and recommendations whose aim is to generate an architecture that starts from astrophysical resources, in a general sense, and ends up in deployed consumable services (that are themselves astrophysical resources). Focusing on the Data Access Layer (DAL) system architecture, that these standards define, in the last years a web based application has been developed and maintained at INAF-OATs IA2 (Italian National institute for Astrophysics - Astronomical Observatory of Trieste, Italian center of Astronomical Archives) to try to deploy and manage multiple VO (Virtual Observatory) services in a uniform way: VO-Dance. However a set of criticalities have arisen since when the VO-Dance idea has been produced, plus some major changes underwent and are undergoing at the IVOA DAL layer (and related standards): this urged IA2 to identify a new solution for its own service layer. Keeping on the basic ideas from VO-Dance (simple service configuration, service instantiation at call time and modularity) while switching to different software technologies (e.g. dismissing Java Reflection in favour of Enterprise Java Bean, EJB, based solution), the new solution has been sketched out and tested for feasibility. Here we present the results originating from this test study. The main constraints for this new project come from various fields. A better homogenized solution rising from IVOA DAL standards: for example the new DALI (Data Access Layer Interface) specification that acts as a common interface system for previous and oncoming access protocols. The need for a modular system where each component is based upon a single VO specification allowing services to rely on common capabilities instead of homogenizing them inside service components directly. The search for a scalable system that takes advantage from distributed systems. The constraints find answer in the adopted solutions hereafter sketched. The

  19. Study on VoIP Network Information Security%VoIP网络信息安全研究

    Institute of Scientific and Technical Information of China (English)

    张琳琳; 梁冰; 李梦

    2009-01-01

    VoIP是基于分组交换的话音传输技术,与基于电路交换的传统电话架构有很大的不同,导致了VoIP网络特有的安全问题.另外,VoIP网络的实时性要求高,由于IP网络服务自身的特性以及各种安全策略的应用.给VoIP网络的性能和服务质量提出了挑战.对VoIP网络存在的安全威胁及各种安全措施进行分析,并对VoIP系统的部署和VoIP管理政策的制定提出建议.

  20. 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.

  1. 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.

  2. Bezpečnost VoIP protokolů

    OpenAIRE

    František NOVOTNÝ

    2010-01-01

    Předložená bakalářská práce je zaměřena na bezpečnost protokolu VoIP (Voice over Internet Protocol). Nejdříve jsou představeny nejpoužívanější transportní a signalizační protokoly, které jsou využity v této technologii. Práce je zaměřena na dva rozšířené protokoly SIP (Session Initiation Protocol), IAX (Inter-Asterisk eXchange Protocol) a open source Asterisk, který je úzce spjatý s užíváním těchto protokolů. V další části jsou popsány možné útoky, hrozby a metody, které jsou schopny zajistit...

  3. 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...

  4. Cloudspace: virtual environments in the VO

    Science.gov (United States)

    Graham, M. J.; Williams, R. D.

    2008-08-01

    The grid community is moving towards providing on-demand computing in the form of virtual workspaces - abstracted execution environments that are dynamically made available to authorized clients. In part this is a reaction to market forces represented by such commercial initiatives as Amazon EC2 and in part a solution to hot service deployment. One danger, though, is that a multiplicity of implementations will lead to a lack of interoperability. Such a concern in the VO regarding distributed data storage led to the development of VOSpace, a lightweight abstraction layer that sits on top of existing storage solutions such as SRB. In this paper, we introduce Cloudspace, a resource-oriented extension of VOSpace, that incorporates UWS, the VO pattern for managing asynchronous services, to form a natural habitat for virtual environments in the VO. A notable feature of the Cloudspace concept is that distributed data and computing can be managed seamlessly through a single mechanism thus making the astronomer's life easier as we move into a new era of sophisticated computational astronomy.

  5. VO Compliant Visualization of Theoretical Data

    Science.gov (United States)

    Molinaro, M.; Manzato, P.; Pasian, F.; Becciani, U.; Costa, A.; Massimino, P.; Grillo, A.; Comparato, M.; Cassisi, S.; Pietrinferni, A.; Gheller, C.; Brunino, R.

    2010-12-01

    In the painstaking effort aimed at defining standards for the inclusion of theoretical data in the VO by testing the compliance of as many simulation services as possible, some updates delivered by the Italian Theoretical Virtual Observatory (ITVO) project are presented. They include cosmological simulated data archive s and services (at Trieste and Catania Astronomical Observatories and at the CINECA supercomputing centre in Bologna) and stellar simulations data archive s and services (BaSTI, a Bag of Stellar Tracks and Isochrones, maintained at the Teramo Astronomical Observatory). Following an upgrade in BaSTI database and a new Web service endpoint for VisIVOweb in Trieste some improvements in data visualization are presented: from new plots for BaSTI tracks emphasizing star evolution’s key points to their comparison with observational data, from direct 3D visualization of galaxy clusters to their direct online data manipulation server side using the VO-compliant VisIVOWeb service. Finally we present a new unique Web portal for the ITVO project under VObs.it, the Italian effort in the VO world, that collects all information regarding the various tokens of this theoretical virtual observatory project that are spread all over Italy.

  6. ESA Science Archives and associated VO activities

    Science.gov (United States)

    Arviset, Christophe; Baines, Deborah; Barbarisi, Isa; Castellanos, Javier; Cheek, Neil; Costa, Hugo; Fajersztejn, Nicolas; Gonzalez, Juan; Fernandez, Monica; Laruelo, Andrea; Leon, Ignacio; Ortiz, Inaki; Osuna, Pedro; Salgado, Jesus; Tapiador, Daniel

    ESA's European Space Astronomy Centre (ESAC), near Madrid, Spain, hosts most of ESA space based missions' scientific archives, in planetary (Mars Express, Venus Express, Rosetta, Huygens, Giotto, Smart-1, all in ESA Planetary Science Archive), in astronomy (XMM-Newton, Herschel, ISO, Integral, Exosat, Planck) and in solar physics (Soho). All these science archives are operated by a dedicated Science Archives and Virtual Observatory Team (SAT) at ESAC, enabling common and efficient design, development, operations and maintenance of the archives software systems. This also ensures long term preservation and availability of such science archives, as a sustainable service to the science community. ESA space science data can be accessed through powerful and user friendly user interface, as well as from machine scriptable interface and through VO interfaces. Virtual Observatory activities are also fully part of ESA archiving strategy and ESA is a very ac-tive partner in VO initiatives in Europe through Euro-VO AIDA and EuroPlanet and worldwide through the IVOA (International Virtual Observatory Alliance) and the IPDA (International Planetary Data Alliance).

  7. 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.

  8. Facile synthesis and high activity of novel BiVO4/FeVO4 heterojunction photocatalyst for degradation of metronidazole

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • BiVO4/FeVO4 was synthesized by a facile one-step hydrothermal method. • BiVO4/FeVO4 displays superior photocatalytic activity. • The photocatalytic mechanism were discussed in detail. - Abstract: The novel BiVO4/FeVO4 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 BiVO4 and FeVO4, indicating that a heterojunction between BiVO4 and FeVO4 was formed during the hydrothermal reaction. In addition, the photodegradation activity of metronidazole (MNZ) was used as a measurement for photocatalytic performance of BiVO4, FeVO4 and BiVO4/FeVO4 heterojunction photocatalyst. It indicated that under visible light irradiation the photocatalytic activity of BiVO4/FeVO4 heterojunction photocatalyst was very effective, and moreover, much higher than the single BiVO4 or single FeVO4. 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. Urchin-like m-LaVO4 and m-LaVO4/Ag microspheres: Synthesis and characterization

    International Nuclear Information System (INIS)

    The semiconductor nanostructures decorated with noble metals have attracted increasing attention due to their interesting physical and chemical properties. In this work, urchin-like monoclinic (m-) LaVO4 microspheres were prepared by a hydrothermal method and used as a template to fabricate Ag nanoparticle-decorated m-LaVO4 composites. The morphology and structure were characterized by transmission electron microscope, high-resolution transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray. It was found that Ag nanoparticles with narrow size distribution were uniformly loaded on urchin-like m-LaVO4 microspheres, and the resulted composite microspheres showed distinct surface plasmon absorption band compared to pure m-LaVO4 microspheres. Photocatalytic activities of as-prepared samples were examined by studying the degradation of methyl orange solutions under visible-light irradiation (> 400 nm). Results clearly showed that urchin-like m-LaVO4/Ag microspheres possess much higher photocatalytic activity than pure m-LaVO4 microspheres and P25. - Highlights: • m-LaVO4/Ag composites microspheres were fabricated by a hydrothermal method. • m-LaVO4 microspheres show higher photocatalytic activity than m-LaVO4 microspheres. • m-LaVO4/Ag microspheres exhibit a good stability

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

    OpenAIRE

    Jorge M Mendoza; Antonio J Bula; Rafael D Gómez; Lesmes A. Corredor

    2012-01-01

    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 (hidroge...

  12. Variabilidad del estado trófico y la biomasa del fitoplancton de Bahía Concepción, Golfo de California (1997-1999)

    OpenAIRE

    López Cortés, David J.; Ismael Gárate Lizárraga; José J. Bustillos Guzmán; Rosalba Alonso Rodríguez; Iban Murillo Murillo

    2003-01-01

    Con el propósito de determinar la variación de la biomasa del fitoplancton (clorofila a) y el estado trófico de Bahía Concepción ubicada en la parte central oeste del Golfo de California, se realizó un estudio hidro-biológico durante el período de 1997 a 1999. Se determinó la temperatura, la concentración del oxígeno disuelto y de nutrientes inorgánicos (nitrato, nitrito, fosfato y silicato), y la biomasa fitoplanctónica (clorofila a). Las condiciones hidrográficas muestran un período de mezc...

  13. Posibilidades técnicas del uso de biomasa no alimentaria para la obtención de energía en España

    OpenAIRE

    Fuertes Sánchez, Alicia

    2009-01-01

    gías renovables dentro de la producción de energía primaria aumentará en los próximos años. La biomasa es una fuente de energía renovable, esta engloba un grupo de productos energéticos y materias primas que se originan a partir de materia orgánica formada por vía biológica. Dentro del consumo de energía primaria en Europa, en el año 2003 las energías renovables representaron un 6% del total según datos de Eurostat. Dentro de este 6%, un 4% corresponde a biomasa seguida de la energía hidráuli...

  14. Deployment of VoIP Technology: QoS Concerns

    OpenAIRE

    Lazzez, Amor; Slimani, Thabet

    2013-01-01

    Voice over IP (VoIP) is an emerging communication service allowing voice transmission over a private or a public IP network. VoIP allows significant benefits for customers and service providers including cost savings, phone and service portability, mobility, and the integration with other applications. Nevertheless, the deployment of the VoIP technology encounters many challenges such as interoperability issues, security issues, and QoS concerns. Among these disadvantages, QoS issues are cons...

  15. Integrating legacy software toolkits into China-VO system

    Science.gov (United States)

    Wang, Xiao-Qian, Cui, Chen-Zhou, Zhao, Yong-Heng

    2005-12-01

    Virtual Observatory (VO) is a collection of data-archives and software toolkits. It aims to provide astronomers research resources with uniformed interfaces, using advanced information technologies. In this article, we discuss the necessaries and feasibilities of integrating legacy software toolkits into China-VO system at first; then analyse granularity about integrating. Three general integrating methods are given in detail. At last, we introduce an instance of integrating "Image Magick" - an software for image processing and discuss more about VO integration.

  16. Direct synthesis of thermochromic VO2 through hydrothermal reaction

    Science.gov (United States)

    Alie, David; Gedvilas, Lynn; Wang, Zhiwei; Tenent, Robert; Engtrakul, Chaiwat; Yan, Yanfa; Shaheen, Sean E.; Dillon, Anne C.; Ban, Chunmei

    2014-04-01

    Thermochromic VO2 was directly synthesized using hydrothermal techniques. The effects of formation conditions on the structure and morphology of the final product were studied through X-ray diffraction (XRD), and scanning electron microscopy (SEM). Unique hollow sphere morphology was observed for the synthesized VO2 powders. Ex-situ XRD studies after heat treatment confirmed the thermal stability of the VO2 structure. Thermochromic properties, as a consequence of the reversible structural transformation between monoclinic VO2 and tetragonal phases, were observed by Fourier transform infrared spectroscopy (FTIR).

  17. Security Research on VoIP with Watermarking

    Science.gov (United States)

    Hu, Dong; Lee, Ping

    2008-11-01

    With the wide application of VoIP, many problems have occurred. One of the problems is security. The problems with securing VoIP systems, insufficient standardization and lack of security mechanisms emerged the need for new approaches and solutions. In this paper, we propose a new security architecture for VoIP which is based on digital watermarking which is a new, flexible and powerful technology that is increasingly gaining more and more attentions. Besides known applications e.g. to solve copyright protection problems, we propose to use digital watermarking to secure not only transmitted audio but also signaling protocol that VoIP is based on.

  18. Investigation and Examination Method Research on VoIP%VoIP调查取证方法研究

    Institute of Scientific and Technical Information of China (English)

    高洪涛

    2010-01-01

    随着VoIP获得越来越多用户的青睐,许多有关的犯罪活动浮出水面.本文从VoIP基本结构入手,分析了当前VoIP的工作原理和存在的漏洞,进而提出了涉VoIP案件的调查取证方法,对涉VoIP案件的主机、运营商服务器、任意号修改软件等进行了实际分析,为公安实践中应对涉VoIP案件的调查取证工作提供参考.

  19. 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.

  20. VoIP中的关键技术研究%Study on Key Technologies of VoIP

    Institute of Scientific and Technical Information of China (English)

    刘煜禹; 姜国兴; 刘永智

    2007-01-01

    文章介绍了VoIP的基本概念和原理,重点阐述了VoIP的几个关键技术:信令技术、编码技术、静音检测技术、实时传输技术,以及QoS保障技术.分析了现存的问题和VoIP的发展前景.

  1. VO-compliant workflows and science gateways

    Science.gov (United States)

    Castelli, G.; Taffoni, G.; Sciacca, E.; Becciani, U.; Costa, A.; Krokos, M.; Pasian, F.; Vuerli, C.

    2015-06-01

    Workflow and science gateway technologies have been adopted by scientific communities as a valuable tool to carry out complex experiments. They offer the possibility to perform computations for data analysis and simulations, whereas hiding details of the complex infrastructures underneath. There are many workflow management systems covering a large variety of generic services coordinating execution of workflows. In this paper we describe our experiences in creating workflows oriented science gateways based on gUSE/WS-PGRADE technology and in particular we discuss the efforts devoted to develop a VO-compliant web environment.

  2. 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.

  3. The overview of the VoIP technology and application%VoIP技术及其应用

    Institute of Scientific and Technical Information of China (English)

    顾亚平

    2002-01-01

    文章叙述了语音在互联网络上传输VoIP(Voice over IP network)的关键技术、国际标准以及VoIP的应用和发展状况.文章对VoIP的技术体系结构进行了的详细阐述,重点介绍了语音在IP网络上传输时的技术难题和保证VoIP语音通讯质量QoS(Quality of Service)的关键技术.

  4. Bioadsorción de Cadmio (II en Solución Acuosa por Biomasas Fúngicas Biosorption of Cadmium (II in Aqueous Solutions by Fungal Biomass

    Directory of Open Access Journals (Sweden)

    Ismael Acosta

    2007-01-01

    Full Text Available Se determinó la bioadsorción de Cadmio (II en solución por la biomasa celular de quince hongos, por el método colorimétrico de la ditizona. La biomasa de Mucor rouxii IM-80 fue más eficiente en la remoción de Cadmio (II en solución (8.2 mg/g seguida de M. rouxii mutante (7.1 mg/g, A. flavus I (5.9 mg/g y Helminthosporium sp (5.4 mg/g. Para la biomasa de M. rouxii-IM-80, la mayor bioadsorción fue a pH= 5.0-6.0, a 28ºC durante 40 horas con 1.0 mg/200 mL de concentración inicial de Cadmio (II y 80 mg/200 mL de biomasa celular. Se concluye que algunas biomasas fúngicas remueven eficientemente Cadmio (II en solución y pueden utilizarse para descontaminar nichos acuáticos contaminados con este metalThe biosorption of dissolved Cadmium (II using cellular biomass of 15 fungi, using a dithizone colorimetric method, was determined. The Mucor rouxii IM-80 biomass was more efficient in removing Cadmium (II from solution (8.2 mg/g, followed by the M. rouxii mutant (7.1 mg/g, Aspergillus flavus I (5.9 mg/g and Helminthosporium sp (5.4 mg/g biomasses. The highest biosorption for M. rouxii IM-80 was at pH 5.0-6.0, at 28ºC for 40 h employing 1.0 mg/200mL of Cadmium (II as initial concentration, and 80 mg/200 mL of fungal biomass. It was concluded that some fungal biomass efficiently removed Cadmium (II from solution and could be used for decontamination of aquatic habitats polluted with this metal

  5. 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.

  6. Orbitally driven trimerization in LiVO2 and LiVS2: a ``partial Mott transition''

    Science.gov (United States)

    Wu, Hua; Khomskii, D. I.

    2011-03-01

    Layered triangular-lattice transition-metal compounds often display interesting magnetic and electronic properties. Here we studied the formation of the trimerized spin-singlet state of the V3+ (S = 1) in vanadates Li VO2 and Li VS2 and their electronic structure with a special orbital order, using constrained LSDA+ U calculations combined with lattice optimization. The obtained results show that the trimerization distortion in Li VO2 increases as the effective U decreases, and the calculated distortion of ~ 0.3 AA at the small U = 1 eV agrees well with the experiments, indicating that Li VO2 is close to a metal-insulator transition. The corresponding distortion in Li VS2 is even stronger, being ~ 0.4 AA at the U = 1 eV, which is due to enhanced electron delocalization via increased V-S covalency, in spite of a lattice expansion. This agrees with the experimental finding that Li VS2 has a metal-insulator transition. The calculated energy gain associated with the trimerization well accounts for the observed structural phase transition temperature in Li VO2 and Li VS2 . We conclude that the trimerization in Li VO2 and Li VS2 is due to a partial delocalization of the orbitally ordered electrons---a ``partial Mott transition,'' occurring not in the whole system but in small clusters (here in trimers). This situation is contrasted with that in Na VO2 , which is further away from the localized-itinerant crossover and thus remains insulating with different orbital ordering.

  7. Discussion on Application of VoIP Technology in School Network%初探VoIP技术在校园网络体系中的应用

    Institute of Scientific and Technical Information of China (English)

    戴国梁; 程线

    2005-01-01

    文中从VoIP技术的先进技术模式出发,分析教育城域网VoIP应用和VoIP语音系统的优缺点,探究VoIP技术的出现对现有的校园网络的影响,进而分析VoIP技术在校园网络体系中的应用.

  8. 初探VoIP技术在校园网络体系中的应用%On Application of VoIP Technology in School Network

    Institute of Scientific and Technical Information of China (English)

    汤志刚

    2005-01-01

    本文就从VoIP技术的先进技术模式出发,分析教育城域网VoIP应用和VoIP语音系统的优缺点,探究VoIP技术的出现对现有的校园网络的影响,进而分析VoIP技术在校园网络体系中的应用.

  9. On Application of VoIP Technology in School Network%VoIP技术在校园网络体系中的应用

    Institute of Scientific and Technical Information of China (English)

    戴国梁; 程线

    2005-01-01

    本文就从VoIP技术的先进技术模式出发,分析教育城域网VoIP应用和VoIP语音系统的优缺点,探究VoIP技术的出现对现有的校园网络的影响,进而分析VoIP技术在校园网络体系中的应用.

  10. Monitorování provozu VoIP pomocí technologie OnePK

    OpenAIRE

    Spišiak, Matej

    2014-01-01

    Tato bakalářská práce se zabývá novou proprietární technologií od Cisco Systems zvanou OnePK (One Platform Kit). Soustřeďuje se na možnosti použití v oblasti zberu statistických dat o VoIP provozu. Používá DataPath service set, ktorý zabezpečuje sběr paketů ze síťových zařízení firmy Cisco. DataPath service set posílá pakety na vstup aplikace, která tvoří VoIP statistiku z příchozích SIP paketů. Tato aplikace a provedené testy na technologii OnePK jsou výsledky této práce....

  11. 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. PMID:18552104

  12. 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.

  13. Regulatory legacy, VoIP adoption and investment incentives

    OpenAIRE

    Paul de Bijl; Peitz, M.

    2010-01-01

    Access regulation has been designed for PSTN and the liberalization of the PSTN market. This paper explores the effects of the regulation on consumers’ adoption of a new technology in the form of VoIP. It also discusses the link between access regulation and the incentives to invest in VoIP.

  14. Using VO Concept for Managing Dynamic Security Associations

    NARCIS (Netherlands)

    Y. Demchenko; L. Gommans; C.T.A.M. de Laat

    2006-01-01

    This research paper presents results of the analysis how the Virtual Organisation (VO) concept can be used for managing dynamic security associations in collaborative applications and for complex resource provisioning. The paper provides an overview of the current practice in VO management at the or

  15. Microstructures and thermochromic characteristics of VO2/AZO composite films

    Science.gov (United States)

    Xiao, Han; Li, Yi; Yuan, Wenrui; Fang, Baoying; Wang, Xiaohua; Hao, Rulong; Wu, Zhengyi; Xu, Tingting; Jiang, Wei; Chen, Peizu

    2016-05-01

    A vanadium dioxide (VO2) thin film was fabricated on a ZnO doped with Al (AZO) conductive glass by magnetron sputtering at room temperature followed by annealing under air atmosphere. The microstructures and optical properties of the thin film were studied. The results showed that the VO2/AZO composite film was poly-crystalline and the AZO layer did not change the preferred growth orientation of VO2. Compared to the VO2 film fabricated on soda-lime glass substrate through the same process and condition, the phase transition temperature of the VO2/AZO composite film was decreased by about 25 °C, thermal hysteresis width narrowed to 6 °C, the visible light transmittance was over 50%, the infrared transmittances before and after phase transition were 21% and 55%, respectively at 1500 nm.

  16. 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.

  17. 基于WLAN中的VoIP的安全技术%Based on the WLAN VoIP Security Technology

    Institute of Scientific and Technical Information of China (English)

    王硕

    2012-01-01

    With the popularity of WLAN technology and the rapid development of VoIP,Both fusion technologies have attracted much attention,While the VoIP security technology applications in WLAN has become the focus of the industry.This paper focuses on the analysis of the VoIP security technology in the WLAN superiority,And to a certain extent to protect their QoS requirements,In order to further prove the feasibility and safety of WLAN+VoIP fusion.%随着WLAN技术的普及以及VoIP的迅速发展,两者融合技术备受关注,而将VoIP安全技术应用在WLAN中成为业界关注的焦点.本文着重分析在WLAN中VoIP安全技术设置,并在一定程度上保障其QoS要求,从而进一步证明了WLAN+VoIP融合的安全性及可行性.

  18. VoIP应用模式的7分法%The Newest Classification of VoIP Application Models

    Institute of Scientific and Technical Information of China (English)

    焦大光; 王延青

    2009-01-01

    随着VoIP产业的迅猛发展,传统的对VoIP应用模式的3类分类法,即PC-PC、PC-Phone、Phone-Phone分类法,已经无法跟上VoIP产业发展的步伐.文中根据VOIP应用所具有的呼叫对称和设备透明两个特性,对VoIP应用模式进行了重新分类,提出了7类分类法.在此基础上,对这7种应用模式的经济性进行了对比分析,并将这7种应用模式与VoIP产业发展的三个阶段进行关联.

  19. Design of VoIP comprehensive experimental platform%VoIP综合实验平台设计

    Institute of Scientific and Technical Information of China (English)

    卢燕飞; 刘云

    2010-01-01

    在IP网络中实现话音通信所采用的技术统称为VoIP.介绍了VoIP技术的主要特点,利用Cisco语音网络设备及相关软件设计了VoIP应用的综合实验平台,详细叙述了实验平台应用的基本原理和实验内容.该实验平台町以提供VoIP中的典型应用方式,同时还可以实现VoIP的多种呼叫控制及服务质量控制.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. SIP-CCME cooperation in multimedia VoIP network

    Science.gov (United States)

    Grądkowska, Magdalena; Popiel, Piotr; Sobańska, Katarzyna

    2006-10-01

    VoIP is a fast-developing technology which allows making telephone calls using a data network like the Internet. VoIP converts the voice signal from the telephone into a digital signal that travels over the Internet and then converts it back at the other end so that speaking to anyone with a regular phone number is possible. VoIP may also enable the direct calls from a computer with the use of a conventional telephone or a microphone. Some services using VoIP may only allow you to call other people using the same VoIP service, but others may allow you to call anyone who has a telephone number. First condition is a broadband Internet connection for VoIP technology to work. There are two major advantages of VOIP: lower cost and increased functionality. In the paper the integration of two networks, one with a CCME based installation and the other with a full Asterisk/SIP voicemail deployment is presented. The goal was to allow dialing between VoIP's telephony from different networks and evaluate a quality of connection with the use of certain codecs.

  5. 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.

  6. Analysis of data communications security for VoIP protocols

    OpenAIRE

    Boongerd, Sanhawad; Lindstein, Fredrik

    2012-01-01

    Voice over IP (VoIP) is a relatively new technology that enables voice calls over data networks.With VoIP it is possible to lower expenses, and increase functionality and flexibility. FromSwedish Armed Forces point of view, the security issue is of great importance, why the focus inthis report is on the security aspect of the two most common open-source VoIP-protocols H.323and SIP, some of the most common attacks, and counter-measures for those attacks.Because of the level of complexity with ...

  7. Access Regulation and the Adoption of VoIP

    OpenAIRE

    Paul de Bijl; Peitz, M.

    2008-01-01

    In this paper, we analyze the effect of access regulation and retail price regulation of PSTN networks on the adoption of a new technology in the form of VoIP. The introduction of packet-switched telephony in the form of VoIP raises concerns about current regulatory practice of access, which has been designed for traditional telephony on PSTN networks. In particular, we show that with endogenous consumer choice between PSTN and VoIP telephony, higher prices for terminating access to the PSTN ...

  8. 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。

  9. On Application of VoIP Technology in City Education Network%VoIP技术在教育城域网体系中的应用

    Institute of Scientific and Technical Information of China (English)

    戴国梁; 程线

    2005-01-01

    VoIP技术的先进技术模式出发,分析教育城域网VoIP应用和VoIP语音系统的现存问题,探究了VoIP技术的出现对现有的校园网络的影响,进而分析VoIP技术在校园网络体系中的应用.阐明了VoIP技术功能强大,只需加入相应的软件,就可以灵活地提供各种服务功能.

  10. 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.

  11. 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

  12. Cambio en el PSI y la RAS de un suelo y su influencia en la actividad biológica y la biomasa microbiana

    OpenAIRE

    Gasca Valderrama, Cesar Augusto

    2010-01-01

    Con el objetivo de evaluar los cambios en el PSI, la RAS y su influencia en la actividad y biomasa mircrobiana del suelo, se aplicaron diversos tratamientos con 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 diseño en bloques completos al azar con cuatro tratamientos y tres repeticiones, y se evaluaron las propiedades del suelo: Actividad biológic...

  13. Estimación de biomasa fitoplanctónica, derivada de datos de satélite, frente a Baja California Sur

    OpenAIRE

    Saúl Álvarez Borrego; Eduardo Santamaría del Ángel; Iriana Leticia Zuria Jordan; Frank E. Müller Karger

    1995-01-01

    Se utilizaron todas las estimaciones disponibles de la concentración de pigmentos fotosintéticos derivadas de datos generados por el sensor Coastal Zone Color Scanner (CZCS) en el periodo 19781986, para interpretar las variaciones espaciales y temporales de la biomasa de fítoplancton, en un transecto de punta San Hipólito (27”N, ll4”30’0) a cabo Corrientes (20”3O’N, 105”30’0), frente al sur de Baja California, México. Las mayores concentraciones de pigmentos fotosintéticos se presentaron cerc...

  14. Cuantificación de biomasa y carbono en bosques nativos de Prosopis caldenia (Burkart) en la Pampa semiárida, Argentina.

    OpenAIRE

    Risio Allione, Lucía

    2012-01-01

    Los bosques del sur-oeste de la pampa Argentina están dominados por caldén (Prosopis caldenia). En la actualidad resta el 18 % de su superficie original. Existen iniciativas que reconocen a los bosques su rol de oferentes de servicios ambientales pero para alcanzar esta recompensa económica es necesario cuantificar la cantidad de carbono almacenado en ellos. En este trabajo se desarrolló un modelo de estimación de biomasa para caldén a partir de 38 árboles apeados y seccionados. Se ajustó un ...

  15. Análisis de la situación actual del aprovechamiento de la biomasa para producción de electricidad en España

    OpenAIRE

    Varela Antón, Daniel

    2013-01-01

    La actual situación de crisis mundial unido al aumento de precio de los combustibles tradicionales y los efectos sobre el clima que estos suponen, crean la necesidad en la sociedad moderna de encontrar nuevas fuentes de abastecimiento energético. En este proyecto se pretende dar a conocer las tecnologías actuales para la producción eléctrica mediante el empleo de la biomasa en sus diferentes formas, sin olvidar algunas otras aplicaciones como la generación térmica y la automoci...

  16. Uso de la biomasa como fuente de energía para el secado agroindustrial del café: estudio de caso

    OpenAIRE

    Luis Zamora González; Bienvenido Sarría López; Yusleidis Cisnero Reyna

    2005-01-01

    El trabajo trata sobre el análisis de siete variantes de calentamiento del aire que se emplea en el proceso de secado del café, teniendo en cuenta los aspectos térmicos, hidrodinámicos, energéticos, exergéticos y económicos, con la singularidad de que la biomasa se quema en un Horno de Capa Cónica Deslizante (HCCD). Se concluye que la variante número seis reúne las condiciones más atractivas para su utilización en el proceso de calentamiento del aire, utilizado en el secado del café,...

  17. Modelización de la producción de biomasa de Eucalyptus nitens (Deane & Maiden) Maiden en corta rotación para cultivo energético

    OpenAIRE

    González-García, M

    2016-01-01

    La biomasa forestal es una fuente de energía renovable cuyo uso genera beneficios de tipo ambiental, económico y social. En los últimos años el cultivo de Eucalyptus nitens (Deane & Maiden) Maiden para producción de biomasa se han extendido por el Noroeste de España. Los objetivos de esta Tesis Doctoral se centran en la modelización forestal de plantaciones energéticas de esta especie con el fin de estimar su productividad y proporcionar las herramientas para optimizar la producc...

  18. Zn2(OH)3VO3∶Eu3+纳米晶的水热合成及发光性能%Hydrothermal Synthesis and Luminescence Properties of Zn2(OH)3VO3 ∶ Eu3+ Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    寇俊娇; 刘连利; 王莉丽; 侯冰; 王绘; 李万鑫

    2015-01-01

    NaVO3、Zn(NC3)2·6H2O为原料,采用水热法合成了铕离子掺杂Zn2 (OH)3 VO3纳米晶体.运用X射线粉末衍射、扫描电子显微镜、荧光测试仪对纳米晶进行了表征,研究了水乙醇体系不同pH值对产物晶相、微观形貌及荧光性能的影响.在溶剂体系pH值为7~10时,得到片状的Zn2 (OH)3 VO3,而在pH值为4~6和11~12时得到Zn3 (OH)2V2O7·2H2O,表明强酸性和强碱性的溶剂体系都不太适合Zn2 (OH)3 VO3的合成,而最佳的合成体系为中性偏碱性;荧光测试表明在pH=10的水乙醇体系下合成的Zn2(OH)3VO3∶8%Eu3+纳米片的荧光性能最好,其中发射主峰位于612 nm处.

  19. The realization of signaling proxy in VoIP%信令代理在VoIP中的实现

    Institute of Scientific and Technical Information of China (English)

    周荣; 郑建彬

    2006-01-01

    VoIP技术发展至今,安全和资源浪费已经成为其发展的瓶颈,将信令代理应用到VoIP中可以很好地解决这个问题.并分析了当前VoIP存在的诸多不足,提出了基于信令代理的解决方案,并详细地介绍了其原理、结构和实现的算法.

  20. 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.

  1. VoIP现状及安全性研究

    Institute of Scientific and Technical Information of China (English)

    高大鹏; 乔立龙; 王伟

    2009-01-01

    VoIP技术是把标准的电话信号变成压缩的数据包,接着通过Ethernet局域网进行传输或通过IsP的数据网络在全球范围内传输,而不是通过传统的电话线传输.导致了VOIP网络特有的安全问题.另外,VOIP网络的实时性要求高,给VoIP网络的性能和服务质量提出了挑战.本文对VoIP网络存在的安全威胁及各种安全措施进行分析,并对VOIP系统的部署和VoIP管理政策的制定提出建议.

  2. 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,

  3. ANALISIS KORELASI FAKTOR PERILAKU KONSUMEN TERHADAP KEPUTUSAN PENGGUNAAN TEKNOLOGI KOMUNIKASI VoIP

    OpenAIRE

    Budi Yulianto

    2014-01-01

    The advancement of communication technology that is combined with computer and the Internet brings Internet Telephony or VoIP (Voice over Internet Protocol). Through VoIP technology, the cost of telecommunications in particular for international direct dialing (IDD) can be reduced. This research analyzes the growth rate of VoIP users, the correlation of the consumer behavior towards using VoIP, and cost comparisons of using telecommunication services between VoIP and other operato...

  4. A European Perspective of VoIP in Market Competition

    OpenAIRE

    FEIJÓO GONZÁLEZ Claudio; GOMEZ-BARROSO Jose-Luis; ROJO-ALONSO David

    2008-01-01

    The debate on the future of VoIP (Voice over Internet Protocol) is not new. For some time now this technological innovation has been considered one of main drivers for reshaping the telecommunications industry. Such is the case that even former Federal Communications Commission Chairman, Michael Powell, said at the Davos World Economic Forum (Switzerland, January 2004) that VoIP ¿is probably the most significant paradigm shift in the entire history of modern communications, since the inventio...

  5. Mathematical Representation of VoIP Connection Delay

    Directory of Open Access Journals (Sweden)

    M. Halas

    2007-09-01

    Full Text Available The main topic of this article is to define mathematical formulation of VoIP connection delay model. It handles about all partial delay components, the mechanism of their generation, facilities and their mathematical formulation. Thereafter based on mathematical formulation of all partial delay components, the final mathematical model of whole VoIP call delay is created. In conclusion of this article the results of the designed mathematical model are compared with the experimentally gained results.

  6. 漫谈VoIP技术及应用

    Institute of Scientific and Technical Information of China (English)

    李冬芬

    2005-01-01

    本文介绍了VoIP的基本原理和系统组成,重点阐述了VoIP的几个关键技术:信令技术、编码技术、实时传输技术、服务质量(Qos)保证技术以及网络传输技术。最后

  7. Future of VoIP over Wireless in Economic Downturn

    OpenAIRE

    Mehdi, Ghazzal

    2009-01-01

    Voice over IP (VoIP) and wireless are revolutionary technologies by all means of modern time which change the attributes of communications dramatically. VoIP has been established as potential alternative to tradition public switched telephone network (PSTN) technology whereas Wireless communication is the most widely used access method where fixed or remote access to network resources is important. Since both technologies have shown their existence in today’s market individually, merger of th...

  8. Implementasi Server VoIP Berbasis SIP Pada LAN Nirkabel

    OpenAIRE

    Mohammad Shoffa Al Arofat; Nurdin Bahtiar; Ragil Saputra

    2013-01-01

    Voice over Internet Protocol (VoIP) merupakan teknologi yang memungkinkan percakapan suara jarak jauh melalui protokol internet. Dalam telekomunikasi, diperlukan teknologi pensinyalan yang berguna untuk membangun, mengawasi, dan melepas hubungan antara dua titik. Salah satu teknologi pensinyalan yang banyak digunakan untuk VoIP adalah Session Initiation Protocol, dengan implementasinya yang berupa perangkat lunak Open SIP Server. Selain pensinyalan, ada beberapa parameter yang perlu diperhati...

  9. Two-dimensional VO2 photonic crystal selective emitter

    International Nuclear Information System (INIS)

    The design and simulation of a two-dimensional (2D) photonic crystal (PhC) selective emitter made of vanadium dioxide (VO2), a type metal oxide with a high temperature resistance, are reported. Spectral emission characteristics of the 2D VO2 PhCs were investigated using the finite difference time domain (FDTD) method. The PhC consists of a periodic array of cylindrical air microcavities. The influences of the geometric characteristic parameters are discussed. The influences of the radius and depth on the emission of the 2D VO2 PhC can be explained based on the coupled-mode theory. The emissivities at wavelengths below the cut-off wavelength were enhanced by increasing the depth. When the depth was much larger than the radius, the cut-off wavelength increased with the radius. The effect of the period on the emissivity at wavelengths less than the period was highly influenced by the diffraction modes. The designed 2D VO2 PhC emitter exhibited a selective emission that was well-matched with InGaAs cells. The spectral emissivities within the convertible wavelength range of the InGaAs cells reached 0.95, and the emissivities for non-convertible wavelengths were less than 0.3. - Highlights: • The lattice structure of metal phase VO2 does not change with temperature. • The influences of scales on the emission of a 2D VO2 PhC are discussed. • A 2D VO2 photonic crystal emitter matched well with InGaAs cell is designed. • The matched VO2 PhC emitter can highly improve the TPV system efficiency

  10. VoIP原理及其在无线局域网中的QoS保障%VoIP principle and application in wireless LAN

    Institute of Scientific and Technical Information of China (English)

    孟川杰; 黄宏光; 王韬; 陈洪; 王凤兰

    2006-01-01

    VoIP技术现正成为一项构建语音网络的重要技术.本文介绍了VoIP的基本原理,以及VoIP在无线局域网中的应用,分析了无线VoIP业务质量中的问题及解决方法.通过某VoIP无线局域网实例说明了WLAN VoIP的结构和配置,并结合VoIP话音质量评价标准,从无线VoIP传送话音所存在的问题出发,着重探讨了解决这些问题的方法.

  11. VoIP Network Simulation Based on the Packet Tracer%基于Packet Tracer的VoIP网络仿真

    Institute of Scientific and Technical Information of China (English)

    窦如林; 施卫娟; 王少平

    2012-01-01

    介绍VoIP工作原理,通过Packet Tracer仿真软件构建VoIP通信网络,对网络中的设备进行配置,实现VoIP通信过程,并对数据传输进行协议分析,为VoIP实验教学提供一种廉价、高效的解决方案。%This paper elaborates on the working principles of VoIP.The Packet Tracer simulation software is employed to build VoIP communication network and manage the configuration of network equipments.The VoIP communication process is implemented and the protocol analysis in data transport is made so as to provide a cheap,efficient solution to VoIP experiment teaching.

  12. The preparation of a plasmonically resonant VO2 thermochromic pigment

    Science.gov (United States)

    Bai, Huaping; Cortie, Michael B.; Maaroof, Abbas I.; Dowd, Annette; Kealley, Catherine; Smith, Geoffrey B.

    2009-02-01

    Vanadium dioxide (VO2) undergoes a reversible metal-insulator transition, normally at ~68 °C. While the properties of continuous semi-transparent coatings of VO2 are well known, there is far less information available concerning the potential use of discrete VO2 nanoparticles as a thermochromic pigment in opaque coatings. Individual VO2 nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO2 nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO2 powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties.

  13. VoIP Technology and Network Communication%VoIP技术与网络通迅

    Institute of Scientific and Technical Information of China (English)

    孔令旭; 梁福元; 曾玲宏; 王坤

    2010-01-01

    VoIP(Voice over Internet Protocol)是利用 IP 网络传送语音信息的一种通信技术,本文简要介绍了VOIP的基本原理、技术优势和实现方式,详细论述了VOIP的关键技术、产品类型和部署方案,对企业构建VOIP通迅网有一定的指导意义.

  14. 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.

  15. 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.)

  16. 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。

  17. 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

  18. VoIP安全问题及对策研究%Research on Security Problem and Solutions of VoIP

    Institute of Scientific and Technical Information of China (English)

    魏建行; 李超; 张彬

    2006-01-01

    作为一种基于IP网络的新兴应用技术,VoIP继承了IP数据网络的若干安全漏洞.通过分析VoIP原理及协议体系,讨论了VoIP系统的安全隐患,并提出相应的防范对策.

  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. The Core Network Solution Based on VoLTE%VoLTE的核心网解决方案

    Institute of Scientific and Technical Information of China (English)

    于艳丽; 张艳

    2014-01-01

    进入2013年,全球LTE商用网络数量出现快速增长,伴随着移动通信核心网向全网IP化及扁平化推进,以及VoLTE技术的成熟和商用,基于IMS系统控制的VoLTE技术将作为LTE网络支持语音业务的主要应对策略。如何保证话音质量,不影响客户体验?如何最小化核心网的升级改造投资?如何平滑升级到支持VoLTE的核心网?本文将围绕上述问题展开讨论。%The global number of LTE network grows rapidly in 2013, with the evolution of mobile core network to the entire IP and flattening network. VoLTE based on the IMS system control will become the main strategy of LTE supporting voice business for the maturity of VoLTE technology. How to ensure the quality of voice not to affect the customer experience? How to minimize the core network upgrading investment? How upgrade to the core network supporting VoLTE smoothly? This article will discuss the above problems.

  1. 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.

  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. 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.

  4. 公用信道技术在VoIP中的应用

    Institute of Scientific and Technical Information of China (English)

    畅健

    2008-01-01

    随着Internet的发展,VoIP获得了广泛应用.目前的VoIP有多种协议,但是传统VoIP服务器只能够支持单一的协议,不同VoIP协议的互通问题始终是VoIP发展中的核心问题.本文基于公用信道思想,介绍了一种使用多协议的voIP技术.

  5. 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...

  6. Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition

    International Nuclear Information System (INIS)

    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) VO2 crystallites to a percolating granular configuration. • 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. - Abstract: 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

  7. Thermochromic characteristics of Ti-doped VO2 thin film

    Science.gov (United States)

    Lee, Hwasoo; Ko, Kyung Hyun; Choi, Jun Oh

    2014-03-01

    Utilizing metal-to-insulator transition (MIT) properties of V-oxide film, stable VO2 phase is necessary. In sputtering deposition of VO2, simple target preparation and high deposition rate are recommendable. For this, VO2 film was deposited on quartz substrate by RF magnetron sputter system under low working pressure using V2O5 target. Due to the lower sputtering yield of oxygen compared to vanadium, oxygen ion contents is usually deficient from that of target. So, the reduction of V ions was a result of charge compensation with the oxygen ions. Under lower working pressure, deposition rate become higher so that this deficiency is getting larger to cause further reduction to destabilize VO2. Preventing this, titanium oxide co-deposition was suggested to enrich oxygen source. When TiO2 was used, Ti ion has stable +4 charge state so that extra oxygen sputtered prevents V ion reduction below +4 state. But, in case of TiO, Ti ions were oxidized from +2 to +3 and +4 state and V ions with less oxidation potential should be reduced to +3 or so. Pure VO2 film had MIT at 66°C and large resistivity ratio of 4 orders of magnitude from 30°C to 90°C. Under low working pressure, (V2O5 + TiO2) system yield fairly good films, while films with poor or absence of MIT were produced with TiO case.

  8. Direct synthesis of thermochromic VO{sub 2} through hydrothermal reaction

    Energy Technology Data Exchange (ETDEWEB)

    Alie, David [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States); University of Denver, 2199 South High Street, Denver, CO (United States); Gedvilas, Lynn [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States); Wang, Zhiwei [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States); The University of Toledo, Toledo, OH 43606 (United States); Tenent, Robert; Engtrakul, Chaiwat [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States); Yan, Yanfa [The University of Toledo, Toledo, OH 43606 (United States); Shaheen, Sean E. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States); University of Denver, 2199 South High Street, Denver, CO (United States); Dillon, Anne C. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States); Ban, Chunmei, E-mail: chunmei.ban@nrel.gov [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO (United States)

    2014-04-01

    Thermochromic VO{sub 2} was directly synthesized using hydrothermal techniques. The effects of formation conditions on the structure and morphology of the final product were studied through X-ray diffraction (XRD), and scanning electron microscopy (SEM). Unique hollow sphere morphology was observed for the synthesized VO{sub 2} powders. Ex-situ XRD studies after heat treatment confirmed the thermal stability of the VO{sub 2} structure. Thermochromic properties, as a consequence of the reversible structural transformation between monoclinic VO{sub 2} and tetragonal phases, were observed by Fourier transform infrared spectroscopy (FTIR). - Graphical abstract: Thermochromic VO{sub 2} crystals with hollow spherical and asterisk shape were directly synthesized using hydrothermal techniques. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies confirmed the thermal stability and the reversible thermochromic properties of the VO{sub 2} structure. - Highlights: • One-step synthesis of thermochromic VO{sub 2} monoclinic phase, and VO{sub 2} (A and B phases) using hydrothermal technique. VO{sub 2} (A), VO{sub 2} (B). • Identification of the relationship between synthesis conditions and the morphology/structure of the final products. • Formation of VO{sub 2} monoclinic phase with an interesting hollow sphere shape. • Demonstration of superior thermal stability of the VO{sub 2} monoclinic phase. • Characterizing the thermochromic properties of VO{sub 2} monoclinic phase.

  9. Chloroform fumigation-extraction labile C pool (microbial biomass C "plus" shows high correlation to microbial biomass C in Argentinian and Brazilian soils Alta correlación entre el "pool" de carbono lábil por fumigación con cloroformo-extracción (carbono de biomasa microbiana plus y carbono de biomasa microbiana en suelos de Argentina y Brasil

    Directory of Open Access Journals (Sweden)

    Helvécio De-Polli

    2007-07-01

    Full Text Available Chloroform fumigation-incubation and chloroform fumigation-extraction approaches have significantly contributed to assess soil microbial biomass. Some controversy is found in the literature about the suggestion to calculate microbial biomass carbon (MBC without the subtraction of the un-fumigated control, in opposition to the originally proposed method that requires such subtraction. Some authors consider the non-subtraction proceeding as a more robust method. Nevertheless, values obtained without subtraction of a control include other labile organic fractions of soil carbon besides microbial biomass. Therefore, due to the usefulness of this measurement we consider more appropriate to call it as chloroform-fumigation labile C pool or microbial biomass carbon "plus" (MBC PLUS. We used a vast series of data from soils of Argentina and Brazil under different management situations to verify whether MBC correlates to MBC PLUS. There was a significant statistical correlation between values of MBC obtained by fumigation-extraction method and the corresponding MBC PLUS. The MBC PLUS performed as well as MBC as an indicator to differentiate soil managements and their impact on soil quality.Los métodos de fumigación-incubación y fumigación extracción han contribuido significativamente a las determinaciones de biomasa microbiana del suelo. En la literatura se encuentran algunas controversias acerca de la sugerencia de calcular el carbono de biomasa microbiana (CBM sin la sustracción del control no fumigado, en oposición a las metodologías tradicionales que requieren de dicha sustracción. Algunos autores mencionan que el hecho de no realizar la sustracción hace al procedimiento más robusto. Sin embargo, los valores obtenidos sin la sustracción del control incluyen otras fracciones lábiles del carbono, además de la biomasa microbiana. Debido a lo útil que resulta esta medida consideramos adecuado llamarla "pool" de carbono lábil por fumigaci

  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. 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.

  12. 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.

  13. 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.

  14. 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

  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. Design and implementation of SIP VoIP Adapter

    OpenAIRE

    Guixà Ibàñez, Adrià

    2009-01-01

    Projecte fet en col.laboració amb École Central d'Eléctronique de Paris The SIP VoIP Adapter is a Java application that is able to establish a SIP communication acting as a User Agent, which uses an external device as a sound device, to play and acquire the audio from the call established through Asterisk PBX. The SIP VoIP Adapter has been also implemented to be able to use and independent audio data codecs for both audio communications, the RTP communications between SIP clien...

  17. Phase Transformation of VO2 Nanoparticles Assisted by Microwave Heating

    Directory of Open Access Journals (Sweden)

    Phatcharee Phoempoon

    2014-01-01

    Full Text Available The microwave assisted synthesis nowadays attracts a great deal of attention. Monoclinic phase VO2 (M was prepared from NH4VO3 and H2C2O4·2H2O by a rapid microwave assisted technique. The synthesis parameters, microwave irradiation time, microwave power, and calcinations temperature were systematically varied and their influences on the structure and morphology were evaluated. The microwave power level has been carried out in range 180–600 W. TEM analysis demonstrated nanosized samples. The structural and morphological properties were measured using XRD, TEM, and thermal analyses. The variations of vanadium phase led to thermochromic properties.

  18. 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...

  19. Pressure-induced phase transitions and metallization in VO2

    OpenAIRE

    Bai, Ligang; Li, Quan; Corr, Serena A; Meng, Yue; Park, Changyong; Sinogeikin, Stanislav V.; Ko, Changhyun; Wu, Junqiao; Shen, Guoyin

    2015-01-01

    We report the results of pressure-induced phase transitions and metallization in VO2 based on synchrotron x-ray diffraction, electrical resistivity, and Raman spectroscopy. Our isothermal compression experiments at room temperature and 383 K show that the room temperature monoclinic phase (M1,P21/c) and the high-temperature rutile phase (R,P42/mnm) of VO2 undergo phase transitions to a distorted M1 monoclinic phase (M1′,P21/c) above 13.0 GPa and to an orthorhombic phase (CaCl2-like, Pnnm) abo...

  20. Utjecaj modifikacije karbamid-formaldehidne smole s utekućenim drvom na svojstva ploča iverica

    OpenAIRE

    Antonović, Alan; Jambreković, Vladimir; Kljak, Jaroslav; ŠPANIĆ, NIKOLA; Medved , Sergej

    2010-01-01

    U drvnim kompozitnim materijalima od usitnjenog drva „bezvrijedna“ se biomasa i ostaci nakon uporabe pretvaraju u vrijedan materijal. Problem primjene ostalih nužnih sintetičkih kemijskih komponenata, osobito ljepila koja su esencijalne nedrvne komponente u proizvodnji drvnih kompozita (uglavnom naftni derivati), već je odavno predmetom znanstvenih istraživanja koja daju pozitivne rezultate. Vezano za navedenu problematiku, brojna su istraživanja usmjerena na utekućenje drva i primjenu utekuć...

  1. JEDNA METODA OSTVARIVANJA POZIVA TEMELJENA NA ODREĐENOM SUSTAVU OTVORENOG KODA TELEFONSKE CENTRALE

    OpenAIRE

    Bilas, Tihi; Batoš, Vedran; Nemčić, Boris

    2010-01-01

    U radu su prikazani trendovi razvoja i implementacije VoIP nasuprot tradicionalnoj tehnologiji. Poseban naglasak dan je na statistike nekih europskih država, povećanje broja korisnika VoIP usluge i predviđanja razvoja spomenutoga u bliskoj budućnosti. Također je prikazana primjena sustava otvorenoga koda pri ostvarivanju telefonskih poziva. Na temelju analize postojećeg sustava, standardnih procedura i raspoložive tehnologije, predložena je jedna metoda ostvarivanja poziva temeljena na određe...

  2. 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.

  3. 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

  4. 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.

  5. A low cost preparation of VO{sub 2} thin films with improved thermochromic properties from a solution-based process

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Lili [Key Laboratory of Renewable Energy and Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Miao, Lei, E-mail: miaolei@ms.giec.ac.cn [Key Laboratory of Renewable Energy and Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Tanemura, Sakae, E-mail: fwhy7074@mb.infoweb.ne.jp [Key Laboratory of Renewable Energy and Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China); Powder Technology PJ Lab., Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587 (Japan); Zhou, Jianhua; Chen, Lihua; Xiao, Xiudi; Xu, Gang [Key Laboratory of Renewable Energy and Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2013-09-30

    This paper describes a solution-based route to synthesize vanadium dioxide (VO{sub 2}) thermochromic thin films on glass substrate by spin-coating technology followed by nitrogen-annealing with vanadium pentoxide (V{sub 2}O{sub 5}) and oxalic acid (H{sub 2}C{sub 2}O{sub 4}) as source material, which is fairly economical and practical. Surface morphologies indicate that the films obtained by this method are homogeneous and particulate, irregular prisms emerge as the annealing temperatures increase. X-ray diffractions show that films annealed at relatively low temperature are pure monoclinic phase with a preferred orientation of (011). NaV{sub 4}O{sub 7} and NaV{sub 6}O{sub 15} form along with raising the heating temperatures. VO{sub 2} films obtained exhibit excellent visible transparency and switching property at near-infrared wavelengths across the metal–semiconductor transition. Transmittance change at λ = 2000 nm of VO{sub 2} thin film annealed at 450 °C attains as high as 41.5% and its solar modulation efficiency reaches up to 8.8%. The W-doped VO{sub 2} film at a doping level of 1 at.% exhibits a thermochromic switch at 37 °C with a narrow hysteresis, which will greatly favor the practical application of VO{sub 2}-based smart windows. - Highlights: ► Vanadium dioxide thermochromic film was prepared via a solution-based deposition. ► Tungsten doping reduced the phase transition temperature to 37 °C. ► Tungsten doping narrowed the transmittance hysteresis loop. ► Our results will propel the application to vanadium dioxide-based smart windows.

  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. VoIP Client for Multi-core Server Enhancing Quality of Real Time Service Delivery

    OpenAIRE

    Bereka Shewara, Jemil

    2012-01-01

    Voice over Internet Protocol (VoIP) is a fast growing service in communication technology. Due to the cost-effectiveness, many organizations have been deploying VoIP technology for their teleconferencing and video conferencing services. In recent decades, various types of client and server applications have been developed, and different application protocols have been standardized. However, most of VoIP applications were developed for single core architecture. The increasing demand of VoIP se...

  8. Development and Performance Analysis of a Lossless Data Reduction Algorithm for VoIP

    OpenAIRE

    Syed Misbahuddin; Noureddine Boulejfen

    2014-01-01

    VoIP (Voice Over IP) is becoming an alternative way of voice communications over the Internet. To better utilize voice call bandwidth, some standard compression algorithms are applied in VoIP systems. However, these algorithms affect the voice quality with high compression ratios. This paper presents a lossless data reduction technique to improve VoIP data transfer rate over the IP network. The proposed algorithm exploits the data redundancies in digitized VFs (Voice Frames) generated by VoIP...

  9. An Analysis for Anonymity and Unlinkability for a VoIP Conversation

    OpenAIRE

    Zhang, Ge

    2010-01-01

    International audience With the growth of its popularity, VoIP is increasingly popular nowadays. Similarly to other Internet applications, VoIP users may desire to be unlinkable with their participated VoIP session records for privacy issues. In this paper, we explore the Items of Interests (IOIs) from anonymisation aspects based on a simplified VoIP model and analyse the potential links between them. We address possible methods to break the links. Finally, we also discuss requirements for...

  10. TCD-VoIP, a Research Database of Degraded Speech for Assessing Quality in VoIP Applications

    OpenAIRE

    Hines, Andrew; HARTE, NAOMI; Gillen, Eoin

    2015-01-01

    There are many types of degradation which can occur in Voice over IP calls. Degradations which occur independently of the codec, hardware, or network in use are the focus of this paper. The development of new quality metrics for modern communication systems depends heavily on the availability of suitable test and development data with subjective quality scores. A new dataset of VoIP degradations (TCD-VoIP) has been created and is presented in this paper. The dataset contains speech samples wi...

  11. Lokace volajícího při tísňových hovorech VoIP

    OpenAIRE

    Mrník, Martin

    2013-01-01

    Táto diplomová práca sa zaoberá problematikou určovania polohy volajúceho na tiesňovú linku so zameraním na hovory prenášane VoIP protokolom. Obsahuje všeobecne popísané hlavné aktívne a pasívne metódy, ktoré možno pre geolokáciu použiť, a vysvetľuje ich funkciu. V práci je analyzované zastúpenie jednotlivých VoIP klientov a popísaný spôsob fungovania programu Skype. Ťažiskovou témou práce je vytvorenie aplikácie na geolokáciu volajúceho pomocou analýzy VoIP prenosu. Aplikácia vyčítava IP adr...

  12. 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…

  13. 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

  14. Direct and continuous synthesis of VO2 nanoparticles

    Science.gov (United States)

    Powell, M. J.; Marchand, P.; Denis, C. J.; Bear, J. C.; Darr, J. A.; Parkin, I. P.

    2015-11-01

    Monoclinic VO2 nanoparticles are of interest due to the material's thermochromic properties, however, direct synthesis routes to VO2 nanoparticles are often inaccessible due to the high synthesis temperatures or long reaction times required. Herein, we present a two-step synthesis route for the preparation of monoclinic VO2 nanoparticles using Continuous Hydrothermal Flow Synthesis (CHFS) followed by a short post heat treatment step. A range of particle sizes, dependent on synthesis conditions, were produced from 50 to 200 nm by varying reaction temperatures and the residence times in the process. The nanoparticles were characterised by powder X-ray diffraction, Raman and UV/Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The nanoparticles were highly crystalline with rod and sphere-like morphologies present in TEM micrographs, with the size of both the rod and spherical particles being highly dependent on both reaction temperature and residence time. SEM micrographs showed the surface of the powders produced from the CHFS process to be highly uniform. The samples were given a short post synthesis heat treatment to ensure that they were phase pure monoclinic VO2, which led to them exhibiting a large and reversible switch in optical properties (at near-IR wavelengths), which suggests that if such materials can be incorporated into coatings or in composites, they could be used for fenestration in architectural applications.

  15. Modelado de capacidades VoIP en redes corporativas

    OpenAIRE

    Cuesta Puebla, Miguel de la

    2011-01-01

    En este proyecto realizaremos un estudio sobre un proyecto solicitado por una empresa que está interesada en ampliar la red orientando el estudio de las condiciones de calidad del servicio telefónico con tecnología VoIP cuando se amplía la red de datos.

  16. Multi-VO support in IHEP's distributed computing environment

    Science.gov (United States)

    Yan, T.; Suo, B.; Zhao, X. H.; Zhang, X. M.; Ma, Z. T.; Yan, X. F.; Lin, T.; Deng, Z. Y.; Li, W. D.; Belov, S.; Pelevanyuk, I.; Zhemchugov, A.; Cai, H.

    2015-12-01

    Inspired by the success of BESDIRAC, the distributed computing environment based on DIRAC for BESIII experiment, several other experiments operated by Institute of High Energy Physics (IHEP), such as Circular Electron Positron Collider (CEPC), Jiangmen Underground Neutrino Observatory (JUNO), Large High Altitude Air Shower Observatory (LHAASO) and Hard X-ray Modulation Telescope (HXMT) etc, are willing to use DIRAC to integrate the geographically distributed computing resources available by their collaborations. In order to minimize manpower and hardware cost, we extended the BESDIRAC platform to support multi-VO scenario, instead of setting up a self-contained distributed computing environment for each VO. This makes DIRAC as a service for the community of those experiments. To support multi-VO, the system architecture of BESDIRAC is adjusted for scalability. The VOMS and DIRAC servers are reconfigured to manage users and groups belong to several VOs. A lightweight storage resource manager StoRM is employed as the central SE to integrate local and grid data. A frontend system is designed for user's massive job splitting, submission and management, with plugins to support new VOs. A monitoring and accounting system is also considered to easy the system administration and VO related resources usage accounting.

  17. The Research and Application of VoIP Traffic Detection Technology%VoIP流量监测技术的研究与应用

    Institute of Scientific and Technical Information of China (English)

    万兵; 杨阳

    2010-01-01

    目前用于VoIP的流量监测技术主要是基于SIP协议或者H.323协议,其对标准VoIP流量的监测率较高,但是对目前所存在的各种非法VoIP业务的监测能力欠佳.文章提出了一种基于协议分析、端口匹配、深度净荷匹配来监测VoIP流量的综合方法,并运用于实际的VoIP监控系统当中,通过在电信现场环境下的验证,最终表明该方法对VoIP流量的监测准确率较高.

  18. VoIP市场及监控技术的发展%Analysis of Development of VoIP Market and Control Technology

    Institute of Scientific and Technical Information of China (English)

    刘金媛

    2007-01-01

    近几年,VoIP的发展受到了全球关注,很多国家的电信管制机构从国家安全的角度出发,出台了对VoIP执法监听的要求.另外,基础运营商为避免受到VoIP的冲击,也希望对自身网络上的VoIP实现封堵等功能,进而带动了VoIP监控技术的发展.本文对目前VoIP监控设备产品的功能和系统部署方式做了介绍.

  19. VoLTE Customer Perception Improvement and Optimization Method Analysis%提升VoLTE客户感知的优化分析方法浅析

    Institute of Scientific and Technical Information of China (English)

    黄冰柏; 程佳鸣; 林永兴; 黄洁

    2016-01-01

    阐述了Vo LT E网络架构和关键指标体系,研究了Vo LT E端到端分析方法,从主动分析和被动改进两方面入手,提出了六元六域四环分析法,实现了VoLTE客户感知的提升,为VoLTE端到端优化分析提供了方向。%With the VoLTE network architecture and key index system illustrated, the paper studied the end-to-end analysis method. And by active analysis and passive improvement, the paper proposed the six-meta-six-core-four-circle analysis method, improved customer perception, and showed the direction for VoLTE end-to-end analysis optimization.

  20. 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.

  1. The ROI of VoIP: Everybody Says VoIP Saves Big Bucks. But Does It?

    Science.gov (United States)

    Villano, Matt

    2006-01-01

    Advocates of Voice over Internet Protocol (VoIP) say it saves money on long distance calls by sending them over the Internet, improves communication by eliminating the Private Branch Exchange (PBX), and offers a host of neat features such as call forwarding, e-mail accessible voicemail, and more. When it comes to measuring the dollars-and-cents…

  2. 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.

  3. VoIP技术及其在宽带IP网的应用%VoIP Technology and Its Application in Broadband IP Network

    Institute of Scientific and Technical Information of China (English)

    占亿民; 林宝成

    2002-01-01

    本文系统介绍了VoIP信令、语音压缩编码、静音检测、回声消除、IP语音传输和QoS保证等VoIP核心技术,阐述了宽带IP网技术及其承载实时多媒体业务的优势,探讨了VoIP在宽带IP网的多种应用模式,并介绍了VoIP在南京宽带IP网的开发和应用.

  4. VoIP Regulatory Action and Points to Consider of FCC%美国对VoIP监管实践与启示

    Institute of Scientific and Technical Information of China (English)

    杨然

    2005-01-01

    介绍美国FCC针对VoIP监管的最新实践,分析FCC对VoIP所采取的政策和决策的依据及未来管制趋势.从FCC对VoIP的监管实践看,美国对VoIP并不是不管制或者只是"轻管制",除了保证正常的市场竞争秩序外,在与国家安全相关的问题上,则采取非常严格和谨慎的态度.

  5. Variabilidad de estado trófico y la biomasa fitoplanctónica en Bahía Concepción, Golfo de California (1997-1999)

    OpenAIRE

    López Cortés, David J.; Gárate Lizárraga, Ismael; José J. Bustillos Guzmán; Alonso Rodríguez, Rosalba; Murillo Murillo, I.

    2003-01-01

    Con el propósito de determinar la variación de la biomasa del fitoplancton (clorofila a) y el estado trófico de Bahía Concepción ubicada en la parte central oeste del Golfo de California, se realizó un estudio hidro-biológico durante el período de 1997 a 1999. Se determinó la temperatura, la concentración del oxígeno disuelto y de nutrientes inorgánicos (nitrato, nitrito, fosfato y silicato), y la biomasa fitoplanctónica (clorofila a). Las condiciones hidrográficas muestran un período de mezc...

  6. Synthesis, characterization and photocatalytic activities of rare earth-loaded BiVO4 catalysts

    International Nuclear Information System (INIS)

    The BiVO4-based photocatalysts loaded with rare earth (RE=Ho, Sm, Yb, Eu, Gd, Nd, Ce and La) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), nitrogen adsorption for the BET specific surface area and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were evaluated by decolorization of methylene blue (MB) under visible light irradiation. The results of XRD, SEM and XPS analysis deduced that the rare earth ions were present as RE2O3 in the samples. The DRS analysis showed the shift in the absorbption edge from the UV to the visible range: Ho3+-BiVO4 3+-BiVO4 3+-BiVO4 3+-BiVO4 3+-BiVO4 3+-BiVO4 3+-BiVO4 3+-BiVO4 4. Gd3+-BiVO4 had the highest photocatalytic activity among all the RE3+-BiVO4 catalysts. The optimal Gd content was 8 at% under visible light irradiation. This beneficial effect was attributed to the specific electron structure characteristics of gadolinium and the increasing in the separation efficiency of the electron-hole pairs. On the contrast, the other rare earth ions had the detrimental effect on the photocatalytic decolorization of MB.

  7. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2peak)

    Science.gov (United States)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  8. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

    Science.gov (United States)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  9. 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.

  10. 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.

  11. 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.

  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. 基于 SIP 的 P2P VoIP技术研究%Research on P2 P VoIP Technology Based on SIP

    Institute of Scientific and Technical Information of China (English)

    杜经纬

    2015-01-01

    随着三网融合的推进,将会给VoIP带来广阔的发展空间。针对目前常用的VoIP系统存在的网络开销高、呼叫接通率低、信令过于复杂等问题,在对SIP协议在P2P网络环境下实现VoIP的关键技术进行认真分析的基础上,提出了基于SIP的P2P VoIP。通过给出基于SIP的P2P VoIP的基本体系结构,分析了该系统中对等点的发现、用户注册及离线、呼叫建立等功能的实现方法,最后提出了基于SIP的P2P VoIP系统还应该考虑的一些问题。%With the progress in the convergence of the telecommunication, internet and broadcasting networks, VoIP will be presented with broad space for development.However, existing VoIP systems usually suffer from high network overhead, low call completing rate, complex signaling, etc.To solve these problems, this paper, based on a thorough analysis of key technologists involved in VoIP using SIP protocol in the P2P network scenario, proposed the SIP-based P2P VoIP system.By introducing the basic architecture of the SIP-based P2P VoIP system, this paper also analyzes the implementation of functions including peer discovery, user registration and getting offline and call establishment, and points out some questions that should be considered in this system.

  16. VoIP 技术在企业级网络体系中的应用

    Institute of Scientific and Technical Information of China (English)

    张大伟

    2007-01-01

    本文就从VoIP 的先进技术模式出发,分析了企业级网络体系中VoIP的应用以及VoIP 语音系统的特点, 探究了VoIP 技术对企业网络的影响,概述了企业级VoIP体系的建设方案.

  17. 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.

  18. 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.

  19. VO2 thermochromic smart window for energy savings and generation

    Science.gov (United States)

    Zhou, Jiadong; Gao, Yanfeng; Zhang, Zongtao; Luo, Hongjie; Cao, Chuanxiang; Chen, Zhang; Dai, Lei; Liu, Xinling

    2013-01-01

    The ability to achieve energy saving in architectures and optimal solar energy utilisation affects the sustainable development of the human race. Traditional smart windows and solar cells cannot be combined into one device for energy saving and electricity generation. A VO2 film can respond to the environmental temperature to intelligently regulate infrared transmittance while maintaining visible transparency, and can be applied as a thermochromic smart window. Herein, we report for the first time a novel VO2-based smart window that partially utilises light scattering to solar cells around the glass panel for electricity generation. This smart window combines energy-saving and generation in one device, and offers potential to intelligently regulate and utilise solar radiation in an efficient manner. PMID:24157625

  20. 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

  1. 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。

  2. 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

  3. 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

  4. Thermochromic light scattering from particulate VO2 layers

    OpenAIRE

    Montero, José; Ji, Yu-Xia; Granqvist, Claes G.; Niklasson, Gunnar A.

    2016-01-01

    Particulate layers of thermochromic (TC) VO2 were made by reactive DC magnetron sputtering of vanadium onto In2O3: Sn-coated glass. The deposits were characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. Specular and diffuse optical transmittance and reflectance were recorded in the 300-2500-nm wavelength range and displayed pronounced TC effects. These properties could be reconciled with a semi-quantitative model based on Lorentz-Mie theory applied to...

  5. VO2 thermochromic smart window for energy savings and generation

    OpenAIRE

    Jiadong Zhou; Yanfeng Gao; Zongtao Zhang; Hongjie Luo; Chuanxiang Cao; Zhang Chen; Lei Dai; Xinling Liu

    2013-01-01

    The ability to achieve energy saving in architectures and optimal solar energy utilisation affects the sustainable development of the human race. Traditional smart windows and solar cells cannot be combined into one device for energy saving and electricity generation. A VO2 film can respond to the environmental temperature to intelligently regulate infrared transmittance while maintaining visible transparency, and can be applied as a thermochromic smart window. Herein, we report for the first...

  6. 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。

  7. Charging of SAML-based federated VoIP services

    OpenAIRE

    Lutz, D J; Lamp, D; Mandic, P; Hecht, F.; Stiller, B.

    2010-01-01

    Whilst SAML-based federations are most often used by academic and semi-commercial institutions that focus only on attribute-based authentication, we foresee a growing interest for service providers providing charged services. Since more and more academic and semi-commercial federation participants offer Voice-over-IP (VoIP) services, this type of service provides an entry point into identity federation based payment. Therefore, this paper describes an approach on how to h...

  8. VoIP模拟电话适配器

    Institute of Scientific and Technical Information of China (English)

    JD.2415

    2005-01-01

    PMC-Sierra公司推出VoIP模拟电话适配器(ATA)平台.作为其住宅用户端设备(CPE)整体解决方案系列中的第一个方案,将为业界带来更佳的VOIP通话质量。该解决方案包括。

  9. 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.

  10. Accuracy of the VO2peak prediction equation in firefighters

    OpenAIRE

    Klaren, Rachel E; Horn, Gavin P.; Fernhall, Bo; Motl, Robert W.

    2014-01-01

    Background A leading contributing factor to firefighter injury and death is lack of fitness. Therefore, the Fire Service Joint Labor Management Wellness-Fitness Initiative (WFI) was established that includes a focus on providing fitness assessments to all fire service personnel. The current fitness assessment includes a submaximal exercise test protocol and associated prediction equation to predict individual VO2peak as a measure of fitness. There is limited information on the accuracy, preci...

  11. 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.

  12. 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.

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    Bharathi Rajeswaran

    2016-03-01

    Full Text Available 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.

  15. Indirect estimation of VO2max in athletes by ACSM’s equation: valid or not?

    Science.gov (United States)

    Koutlianos, N; Dimitros, E; Metaxas, T; Cansiz, M; Deligiannis, AS; Kouidi, E

    2013-01-01

    Aim: The purpose of this study was to assess the indirect calculation of VO2max using ACSM’s equation for Bruce protocol in athletes of different sports and to compare with the directly measured; secondly to develop regression models predicting VO2 max in athletes. Methods: Fifty five male athletes of national and international level (mean age 28.3 ± 5.6 yrs) performed graded exercise test with direct measurement of VO2 through ergospirometric device. Moreover, 3 equations were used for the indirect calculation of VO2max: a) VO2max= (0.2 · Speed) + (0.9 · Speed · Grade) + 3.5 (ACSM running equation), b) regression analysis model using enter method and c) stepwise method based on the measured data of VO2. Age, BMI, speed, grade and exercise time were used as independent variables. Results: Regression analysis using enter method yielded the equation (R=.64, standard error of estimation [SEE] = 6.11): VO2max (ml·kg-1·min-1) = 58.443 - (0.215 · age) - (0.632 · BMI) - (68.639 · grade) + (1.579 · time) while stepwise method (R = .61, SEE = 6.18) led to: VO2max (ml·kg-1·min-1) = 33.971 - (0.291 · age) + (1.481 · time). The calculated values of VO2max from these regression models did not differ significantly from the measured VO2max (p>.05). On the contrary, VO2max calculated from the ACSM’s running equation was significantly higher from the actually measured value by 14.6% (p <.05). Conclusions: In conclusion, it seems that ACSM’s equation is not capable of accurately predicting VO2max in athletes aged 18-37 years using Bruce protocol. Only the regression models were correlated moderately with the actually measured values of VO2max. PMID:24376318

  16. Detection and Control of Illegal VoIP Traffic%非法VoIP行为检测与管控方法的实现

    Institute of Scientific and Technical Information of China (English)

    苏娜; 刘一蓉; 郭昕; 魏明

    2010-01-01

    由于IP网络的开放性和自由性,以及VoIP接入技术的简单易行,非法VoIP业务的管控工作具有重要意义.对VoIP业务监控主要可通过实时监测并分析网络协议,结合流量分析技术的方法,对采集采的流量进行VoIP业务的连接控制协议分析和数据流分析,检测出所有的VoIP业务流量,并判断是否合法.

  17. Monitoring technology and realization of VoIP flow rate%VoIP流量的监测技术与实现

    Institute of Scientific and Technical Information of China (English)

    殷文珊

    2007-01-01

    近几年来,随着VoIP技术的成熟和实现成本的降低,VoIP业务的提供在全球成为热点.目前监测VoIP流量的监测方法主要有信令流监测和媒体流监测两种,论文通过分析其监测原理,总结出监测VoIP流量的实现方法,即将二者监测出来的并集作为VoIP监测的最后结果,这样,一方面保证了比较高的监测率,另一方面又能提供详细的统计信息.

  18. 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.

  19. VoIP技术安全问题分析及增强研究%VoIP technology security problem analysis and enhancement research

    Institute of Scientific and Technical Information of China (English)

    李晨

    2006-01-01

    目前,基于IP网络的话音传输技术(VoIP)已经发展成为一种专门的通信技术,随着它的广泛应用,其所存在的安全问题日益引起人们的关注.本文从VoIP技术现有的安全机制入手,结合IP网络及VoIP的具体业务,对该技术在安全方面存在的漏洞与不足进行了较为详细、全面地说明.并在文章的后半部分对几种用于增强VoIP安全性的技术进行了总结,对VoIP系统的安全性建设提出了建议.

  20. Hydrothermal Synthesis and Crystal Structure of a Three-dimensional Compound {Mn(H2O)4(VO)2(PO4)2}n

    Institute of Scientific and Technical Information of China (English)

    WU Yang; JIANG Xiao-Yu; ZHANG Quan-Zheng; CHEN Li-Juan; YU Ya-Qin; CHEN Shu-Mei; HE Xiang; YANG Wen-Bin; LU Can-Zhong

    2005-01-01

    The title compound, {Mn(H2O)4(VO)2(PO4)2}n 1, was synthesized by the hydrothermal reaction of Mn(Oac)2, Na2VO3 and H3PO4 in aqueous solution and its crystal structure was determined by X-ray single-crystal analysis. Crystallographic data for 1: H4MnO14P2V2, tetragonal system, space group I4/mmm, a = 6.251(3), c = 13.410(9) (A), Mr = 446.79, V = 524.0(5) (A)3, Z = 2, F(000) = 434, μ = 3.320 mm-1, Dc = 2.832 g/cm3, the final R = 0.0577 for 163 observed reflections (I > 2σ(I)). X-ray crystal structure analysis shows that the vanadium phosphorous oxide layers are further connected by MnII(H2O)4 cations to form a three-dimensional network.

  1. Optical properties and electronic band structure of BiMg2PO6, BiMg2VO6, BiMg2VO6:Pr3+ and BiMg2VO6:Eu3+

    Science.gov (United States)

    Barros, A.; Deloncle, R.; Deschamp, J.; Boutinaud, P.; Chadeyron, G.; Mahiou, R.; Cavalli, E.; Brik, M. G.

    2014-08-01

    The luminescence properties of the yellow pigment BiMg2VO6 are revisited and those of BiMg2PO6, BiMg2VO6:Pr3+ and BiMg2VO6:Eu3+ are described. It is shown that the undoped systems exhibit broad band emission in the green or orange spectral regions, but only upon UV or near UV excitation. In contradiction with a previous report, we found that the blue, host absorbed, photons are lost non-radiatively and do not contribute to the luminescence processes in BiMg2VO6. To understand these experimental results, the optical properties of BiMg2VO6 and BiMg2PO6 are theoretically analysed on the basis of electronic structure diagrams calculated by the DFT method. It is found that the optical transitions are mostly localised within [VO4]3- units or non-regular Bi3+ ions and occur in the UV or near UV regions. The luminescence of the trivalent lanthanide dopants is weak (Eu3+) or unobserved (Pr3+) in BiMg2VO6 which is explained by inefficient energy migration in the host lattice to the impurity sites.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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. PMID:27603090

  7. 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.

  8. 关于典型VoIP安全隐患的分析

    Institute of Scientific and Technical Information of China (English)

    张铁君; 张慧博

    2009-01-01

    随着VoIP(网络电话)技术的不断普及,对网络运营商、设备制造商以及用户而言,除性能改善、成本降低以及强大的技术支持外,VoIP的安全更是不容忽视的问题.本文根据目前VoIP的应用现状,着重分析了VoIP的几种典型安全隐患,为企业用户制定VoIP安全策略,顺利部署自己的VoIP提供参考.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Hydrothermal Synthesis and Structure Analysis of Indium Vanadate (InVO4)

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In this article, hydrothermal process is applied to synthesize nanometer InVO4.Influences of different experimental conditions (including mixing ratio of raw materials, reaction temperature, reaction time and so on) upon the synthetic products' purity and crystallite size are discussed to determine the best synthetic condition. The structure of nanometer InVO4 is analyzed,which helps to further understand the structure characteristics of InVO4 synthesized by applying hydrothermal process and lays foundation for further research.

  14. Effect of Oxide Buffer Layer on the Thermochromic Properties of VO2 Thin Films

    Science.gov (United States)

    Koo, Hyun; Xu, Lu; Ko, Kyeong-Eun; Ahn, Seunghyun; Chang, Se-Hong; Park, Chan

    2013-12-01

    VO2 thin films were deposited on soda lime glass substrates with ZnO, TiO2, SnO2, and CeO2 thin films applied as buffer layers between the VO2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO2 film. Buffer layers with thicknesses over 50 nm were found to affect the formation of VO2 film, which was confirmed by XRD spectra. By using ZnO, TiO2, and SnO2 buffer layers, monoclinic VO2 (VO2(M)) film was successfully fabricated on soda lime glass at 370 °C. On the contrary, films of VO2(B), which is known to have no phase transition near room temperature, were formed rather than VO2(M) when the film was deposited on CeO2 buffer layer at the same film deposition temperature. The excellent thermochromic properties of the films deposited on ZnO, TiO2, and SnO2 buffer layers were confirmed from the temperature dependence of electrical resistivity from room temperature to 80 °C. Especially, due to the tendency of ZnO thin film to grow with a high degree of preferred orientation on soda lime glass at low temperature, the VO2 film deposited on ZnO buffer layer exhibits the best thermochromic properties compared to those on other buffer layer materials used in this study. These results suggest that deposition of VO2 films on soda lime glass at low temperature with excellent thermochromic properties can be achieved by considering the buffer layer material having structural similarity with VO2. Moreover, the degree of crystallization of buffer layer is also related with that of VO2 film, and thus ZnO can be one of the most effective buffer layer materials.

  15. VoIP协议简介与SIP设计原理

    Institute of Scientific and Technical Information of China (English)

    魏楠

    2010-01-01

    VoIP是一种应用于Internet网络上的语音通信业务.VoIP有很多重要协议,例如H.323、MGCP、H.248、SIP等.本文列举了各种VoIP协议的使用特点,并着重阐述了SIP协议.最后给出了一个设计实例说明.

  16. Comparative Study of VoIP over WiMax and WiFi

    OpenAIRE

    M Atif Qureshi; Arjumand Younus; Muhammad Saeed; Farhan Ahmed Sidiqui; Nasir Touheed; M Shahid Qureshi

    2011-01-01

    VoIP is a technology in great demand these days. Its interactive nature makes it very appealing for users and today it is one of the most dominant technologies for communication. With the growth over wireless networks the option to have voice communication over wireless has been considered - the choices are VoIP over WiFi or VoIP over WiMax. This paper studies and compares the two options and summarizes the results.

  17. VoIP Server HW/SW Codesign for Multicore Computing

    OpenAIRE

    Iqbal, Arshad

    2012-01-01

    Modern technologies are growing and Voice over Internet Protocol (VoIP) technology is able to function in heterogeneous networks. VoIP gained wide popularity because it offers cheap calling rates compared to traditional telephone system and the number of VoIP subscribers has increased significantly in recent years. End users need reliable and acceptable call quality in real time communication with best Quality of Service (QoS). Server complexity is increasing to handle all client requests sim...

  18. A study of mobile VoIP performance in wireless broadband networks

    OpenAIRE

    Arjona, Andres

    2009-01-01

    Voice service is to date still the killer mobile service and the main source for operator revenue for years to come. Additionally, voice service will evolve from circuit switched technologies towards packet based Voice over IP (VoIP). However, using VoIP over wireless networks different from 3GPP cellular technologies makes it also a disruptive technology in the traditional telecommunication sector. The focus of this dissertation is on determining mobile VoIP performance in different wir...

  19. CDMA网VoIP带宽算法及影响因素分析

    Institute of Scientific and Technical Information of China (English)

    谢玉生

    2015-01-01

    研究了CDMA网VoIP媒体带宽和信令带宽的算法,对影响媒体带宽6种因素逐一进行分析.另外结合天津电信CDMA核心网络,分析VoIP话务量折合带宽的算法以及VoIP媒体带宽的3种统计方法.

  20. Impact of VoIP and QoS on Open and Distance Learning

    Science.gov (United States)

    Saxena, P. C.; Jasola, Sanjay; Sharma, Ramesh C.

    2006-01-01

    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…

  1. VoIP Technology: Investigation of QoS and Security Issues

    OpenAIRE

    Amor Lazzez

    2014-01-01

    Voice over IP (VoIP) is the technology allowing voice traffic transmission as data packets over a private or a public IP network. VoIP allows significant benefits for customers and communication services providers. The main are cost savings, rich media service, phone and service portability and mobility, and the integration with other applications. Nevertheless, the deployment of the VoIP technology encounters many challenges such as architecture complexity, interoperability problems, QoS co...

  2. Feasibility study of VoIP integration into the MYSEA environment

    OpenAIRE

    Tse, Lily.

    2005-01-01

    Voice over Internet Protocol (VoIP) is becoming popular due to its low cost and the management advantages it offers over traditional PSTN phone systems. VoIP is widely implemented with H.323 and Session Initiation Protocol (SIP) standards. However, both protocols are poorly designed for networks with common security solutions such as firewalls and Network Address Translation (NAT). This project is a feasibility study of SIP-based VoIP integration into the Monterey Security Architecture (M...

  3. A Study of VO2 Max and Body Fat Percentage in Female Athletes

    OpenAIRE

    Shete, Anjali N.; Bute, Smita S; P R Deshmukh

    2014-01-01

    Introduction: Aerobic capacity of athletes is an important element of success in sports achievements. It is generally considered the best indicator of cardio respiratory endurance and athletic fitness. Body fat percentage affects VO2 max and thus the cardiovascular status of the athletes. The present study was undertaken to assess the VO2 max and body fat percentage in athletes. The secondary objective of the study was to study the relationship between VO2 max and body fat percentage.

  4. Phase coexistence in the metal-insulator transition of a VO2 thin film

    International Nuclear Information System (INIS)

    Vanadium dioxide (VO2) shows a metal-insulator transition (MIT) near room temperature, accompanied by an abrupt resistivity change. Since the MIT of VO2 is known to be a first order phase transition, it is valuable to check metallic and insulating phase segregation during the MIT process. We deposited (100)-oriented epitaxial VO2 thin films on R-cut sapphire substrates. From the scanning tunneling spectroscopy (STS) spectra, we could distinguish metallic and insulating regions by probing the band gap. Optical spectroscopic analysis also supported the view that the MIT in VO2 occurs through metal and insulator phase coexistence

  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. Oxygen pressure dependent VO{sub 2} crystal film preparation and the interfacial epitaxial growth study

    Energy Technology Data Exchange (ETDEWEB)

    Fan, L.L.; Wu, Y.F. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029 (China); Si, C. [Institute of High Energy Physics, Chinese Academy of Science, Beijing, 100049 (China); Zou, C.W., E-mail: czou@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029 (China); Qi, Z.M.; Li, L.B.; Pan, G.Q. [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029 (China); Wu, Z.Y., E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029 (China); Institute of High Energy Physics, Chinese Academy of Science, Beijing, 100049 (China)

    2012-07-31

    High quality VO{sub 2} crystal films have been prepared on sapphire substrates by pulsed laser deposition method and the effects of oxygen pressure on the crystal phase structure are investigated. Results indicate that the phases and microstructures of VO{sub 2} films are strongly sensitive to oxygen pressure. High oxygen pressure tends to form coarse B-VO{sub 2} nanocrystals while low pressure favors a flat M1-VO{sub 2} film epitaxial growth. X-ray diffraction {phi}-scan patterns confirm the [020] epitaxial growth orientation of the M1-VO{sub 2} film and the in-plane lattice epitaxial relationship at the interface is also examined. Raman spectra indicate that M1-VO{sub 2} phase has much stronger Raman scattering modes than B-VO{sub 2}, and the clear phonon modes further confirm the idea stoichiometry of VO{sub 2} crystal film. Infrared transmittance spectra as the function of temperature are recorded and the results show that M1-VO{sub 2} crystal films undergo a distinct infrared transmittance variation across metal insulator transition boundary, while B-VO{sub 2} exhibits negligible thermochromic switching properties in the temperature range concerned. The pronounced phase transition behavior of the M1-VO{sub 2} crystal film makes it a promising candidate for optical filter/switch and smart window applications in the future. - Highlights: Black-Right-Pointing-Pointer High quality VO{sub 2} films with different phase structures were obtained by PLD method. Black-Right-Pointing-Pointer High oxygen pressure tends to form B-VO{sub 2} while low pressure favors M1-VO{sub 2} film. Black-Right-Pointing-Pointer {phi}-scan XRD confirms the [020] epitaxial growth orientation of the M1-VO{sub 2} film. Black-Right-Pointing-Pointer The epitaxial relationship is explained based on domain matching theory. Black-Right-Pointing-Pointer M1-VO2 film shows excellent optical property in infrared range.

  7. 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.

  8. 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.

  9. 索菲亚无线VoIP终端概念模型

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    日本索菲亚系统公司推出了无线VoIP终端概念模型“Sandgate VoIP Phone(SGVP)”。该产品具备IEEE802.11b/g无线LAN功能,采用“Windows CE”操作系统。其通过与VoIP软件配合,可用作无线VoIP终端,插上CF卡型PHS卡,还可当作PHS手机使用,被称之为“混合移动终端”。

  10. Quality of Service challenges for Voice over Internet Protocol (VoIP) within the wireless environment

    OpenAIRE

    Peart, Amanda; Adda, Mo

    2008-01-01

    Voice over Internet Protocol (VoIP) is a rapidly growing user technology. Uptake in VoIP technology has significantly increased, especially more recently with the home user moving VoIP away from business dominance. The general population have become accustom to the excellent Quality of Service (QoS) that is now expected from the telecommunications industry both within the landline and mobile infrastructures. QoS within VoIP poses many challenges to be able to compete with the traditional tele...

  11. IAX-Based Peer-to-Peer VoIP Architecture

    OpenAIRE

    Lazzez, Amor; Fredj, Ouissem Ben; Slimani, Thabet

    2013-01-01

    Nowadays, Voice over IP (VoIP) constitutes a privileged field of service innovation. One benefit of the VoIP technology is that it may be deployed using a centralized or a distributed architecture. One of the most efficient approaches used in the deployment of centralized VoIP systems is based on the use of IAX (Inter-Asterisk Exchange), an open-source signaling/data exchange protocol. Even though they are currently widely used, client-server VoIP systems suffer from many weaknesses such as t...

  12. 安全防范措施堵住VoIP安全漏洞

    Institute of Scientific and Technical Information of China (English)

    张美; 叶雷

    2007-01-01

    VoIP存在很多安全隐患,面临很多安全威胁,但是这不是说VoIP的安全性就不可救药,实际上随着安全事件的屡次发生,众多VoIP厂商也在不断的实践中积累着经验,通过一些措施来更大限度的保障VoIP的安全。

  13. Modified Secret Sharing over a Single Path in VoIP with Reliable Data Delivery

    OpenAIRE

    K. Maheswari; Punithavalli, M.

    2012-01-01

    Abstract Voice over Internet Protocol (VoIP) is a new fancy and up growing technology. A major change in telecommunication industry is VoIP. The transmission of Real time voice data is not as easy as ordinary text data. The real time voice transmission faces lot of difficulties. It suffers from packet loss, delay, quality and security. These factors will affects and degrade the performance and quality of a VoIP. This paper addresses the security and packet delivery ratio of a VoIP using modif...

  14. Optimization of thermochromic VO2-based structures with tunable thermal emissivity

    International Nuclear Information System (INIS)

    In this paper we design and simulate VO2/metal multilayers to obtain a large tunability of the thermal emissivity of IR filters in the typical MWIR window of many infrared cameras. The multilayer structure is optimized to realise a low-emissivity filter at high temperatures useful for military purposes. The values of tunability found for VO2/metal multilayers are larger than the value for a single thick layer of VO2. Innovative SiO2/VO2 synthetic opals are also investigated to enhance the optical tunability by combining the properties of a 3D periodic structure and the specific optical properties of vanadium dioxide.

  15. RGO/InVO4 hollowed-out nanofibers: Electrospinning synthesis and its application in photocatalysis

    Science.gov (United States)

    Ma, Dong; Zhang, Yanxiang; Gao, Mengchun; Xin, Yanjun; Wu, Juan; Bao, Nan

    2015-10-01

    A composite of reduced graphene oxide (RGO) and InVO4 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 InVO4 to crystallize and protect the RGO from oxidation. The InVO4 in the composite illustrated a hollowed-out fibrous morphology and orthorhombic phase, and RGO nanosheets were nested in the InVO4 nanofibers. The hybrid RGO could produce more hydroxyl groups and a higher oxygen vacancy density on the surface of RGO/InVO4 composite. Compared with pure InVO4, the light absorption range of the as-prepared RGO/InVO4 composite was expanded. In Rh B degradation, the RGO/InVO4 hybrid nanofibers displayed a higher photocatalytic activity than pure InVO4 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 O2 molecule to facilitate the generation of •O2- and •OH for the photodegradation process of Rh B.

  16. Infrared characteristics of VO2 thin films for smart window and laser protection applications

    International Nuclear Information System (INIS)

    Vanadium dioxide (VO2) films with a low semiconductor-to-metal transition temperature of 45 °C were fabricated through direct current magnetron sputtering followed by a post-annealing. Atomic force microscopy measurements show that the VO2 grain size is about one hundred of nanometers. Infrared (IR) characteristic is well investigated by applying a He-Ne laser power intensity measurement, and the result reveals that the VO2 film exhibits excellent IR switching property. Furthermore, solar smart window and laser protection experiments demonstrate that the obtained VO2 thin film is a promising material for the application in related fields.

  17. 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.

  18. 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.

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

    OpenAIRE

    Ryan Ari Setyawan

    2015-01-01

    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 ...

  20. Analysis of applying softswitch technology in VoIP%软交换技术在VoIP中的应用分析

    Institute of Scientific and Technical Information of China (English)

    姚玉坤; 刘合武

    2006-01-01

    针对目前我国的主要组网协议H.323的VoIP应用网络作了介绍.分析了网关分离模型,对基于软交换技术的下一代网络体系结构作了说明.最后分析了在该网络体系的VoIP应用实现,并阐述了基于软交换技术的VoIP所具有的优势.

  1. 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.

  2. Giant magnetocaloric effect in antiferromagnetic DyVO4 compound

    Science.gov (United States)

    Midya, A.; Khan, N.; Bhoi, D.; Mandal, P.

    2014-09-01

    We have investigated the magnetic and magnetocaloric properties of DyVO4 by magnetization and heat capacity measurements. χ(T) shows antiferromagnetic to paramagnetic transition at TNDy~3.5 K. The compound undergoes a metamagnetic transition and exhibits a huge entropy change. The maximum values of magnetic entropy change (ΔSM), adiabatic temperature change (ΔTad) and refrigerant capacity (RC) reach 26 J kg-1 K-1, 17 K, and 526 J kg-1, respectively for a field change of 0-8 T. Moreover, the material is highly insulating and exhibits no thermal and field hysteresis, satisfying the necessary conditions for a good magnetic refrigerant material.

  3. Thermochromic light scattering from particulate VO2 layers

    Science.gov (United States)

    Montero, José; Ji, Yu-Xia; Granqvist, Claes G.; Niklasson, Gunnar A.

    2016-02-01

    Particulate layers of thermochromic (TC) VO2 were made by reactive DC magnetron sputtering of vanadium onto In2O3:Sn-coated glass. The deposits were characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. Specular and diffuse optical transmittance and reflectance were recorded in the 300-2500-nm wavelength range and displayed pronounced TC effects. These properties could be reconciled with a semi-quantitative model based on Lorentz-Mie theory applied to the distribution of particle sizes and accounting for particle shapes by the Grenfell-Warren approach with equal-volume-to-area spheres.

  4. 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.

  5. Performance analysis and usability in secure VoIP systems

    OpenAIRE

    Pereira, Raquel Sofia Lima

    2015-01-01

    Dissertação de mestrado integrado em Engenharia de Telecomunicações e Informática A tecnologia VoIP (Voice over Internet Protocol) encontra-se num elevado crescimento, que não se encontra ligado à segurança, ou pelo menos são poucos os que se preocupam com isso. Para que seja garantida a confidencialidade, a autenticidade, a integridade e a disponibilidade, considerou-se que a aplicação dos protocolos TLS (Transport Layer Security) e IPSec (IP Security) são atualmente as princi...

  6. 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...

  7. 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.

  8. VoIP Technology: Investigation of QoS and Security Issues

    Directory of Open Access Journals (Sweden)

    Amor Lazzez

    2014-06-01

    Full Text Available Voice over IP (VoIP is the technology allowing voice traffic transmission as data packets over a private or a public IP network. VoIP allows significant benefits for customers and communication services providers. The main are cost savings, rich media service, phone and service portability and mobility, and the integration with other applications. Nevertheless, the deployment of the VoIP technology encounters many challenges such as architecture complexity, interoperability problems, QoS concerns, and security issues. Due to the inability of the IP networking technology to support the stringent QoS constraints of voice traffic, and the incapability of traditional security mechanisms to adequately protect VoIP systems from recent intelligent attacks, QoS and security issues are considered as the most serious challenges for successful deployment of the VoIP technology. The aim of this paper is to carry out a deep analysis of the security issues and QoS concerns of the VoIP technology. Firstly, we present a brief overview about the VoIP technology. Then, we discuss the QoS problems encountering the deployment of the VoIP technology. The presented discussion mainly address the QoS issues related to the use of the IP networking technology, the QoS concerns related to voice clarity, and the QoS mechanisms proposed to support voice traffic QoS constraints. After that, we investigate the security issues of the VoIP technology. The presented investigation mainly address the vulnerabilities and security attacks of VoIP systems, as well as the countermeasures that should be considered to help the deployment of secured VoIP systems.

  9. 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.

  10. Estimación de biomasa y carbono en dos especies de bosque mesófilo de montaña Biomass and carbon assessment in two tree species in a cloudy forest

    Directory of Open Access Journals (Sweden)

    Miguel Acosta Mireles

    2011-08-01

    Full Text Available La generación de ecuaciones alométricas es importante para determinar la biomasa y el carbono en las especies arbóreas. Esta información es útil en los estudios de cambio climático. En el presente estudio se generaron ecuaciones alométricas para dos especies de importancia ecológica en el bosque mesófilo de montaña: Clethra mexicana DC y Alnus arguta (Schltdl Spach. Las ecuaciones que se determinaron son de la forma Y= bXk; donde: Y= contenido de biomasa o de carbono (kg; y X= diámetro normal (DN en centímetros. Para estimar los valores b y k del modelo para cada especie, se realizó un muestreo de quince árboles de Clethra mexicana y 22 de Alnus arguta. En Clethra mexicana el mayor porcentaje de biomasa 45.2 % se encontró en el fuste incluido el tocón, mientras que en las ramas y el follaje estaba 36.3% y 18.6%, respectivamente. Con la biomasa y el DN de los árboles se determinaron los parámetros b y k del modelo propuesto (B= 0.4632 DN1.8168, R²= 0.946. Para Alnus arguta el mayor porcentaje de biomasa (60.6%, se encontró en el fuste incluido el tocón, mientras que en las ramas y el follaje presentó 27.4 y 12%, respectivamente. Al igual que el caso anterior con la biomasa y el DN, se obtuvieron los parámetros b y k del modelo propuesto (B= 0.1649 DN2.2755, R²= 0.968. Después de analizar el contenido de carbono en las muestra de cada especie, se ajustaron las ecuaciones para Clethra mexicana C= 22.49DN1.8168, con R²= 0.946, mientras que para Alnus arguta C= 0.0809DN2.2782 con R²= 0.968.The generation of allometric equations is important to determine biomass and carbon in tree species. This information is useful in climate change studies. In this paper, allometric equations were generated for two species of ecological importance in the cloud forest: Clethra mexicana DC and Alnus arguta (Schltdl Spach. Equations determined are of the form Y= bXk; where: Y= biomass or carbon content (kg; and X= normal diameter (ND in

  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. 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.

  13. Riadenie nákladov na IS/ICT vo vybranej spoločnosti

    OpenAIRE

    Gazda, Štefan

    2013-01-01

    The thesis is focused on IS/ICT cost management. The purpose of this thesis is to create an IS/ICT cost model based on the principles of managerial method ABC (Activity Based Costing) for business informatics of selected company. The theoretical part is focused on costs in IS/ICT, their classification and management, with the analyze of the reasons for continuous growth of IS/ICT cost management. A significant part of this section is a characteristic of ABC method and a description of differe...

  14. Právo na vzdělání

    OpenAIRE

    NESVAČILOVÁ, Iva

    2013-01-01

    The thesis deals with the right to education, it's historical conception up to the current suggested reform of the tertiary education. The main aim of the thesis is to map attitudes of specialists and students to education and the educational reform. In the thesis I applied my mind to the rate of awareness of fees at universities in the Ceske Budejovice region. The bachelor thesis is divided in two parts. The one is theoretical and the second is practical. The basic terms which are connected ...

  15. 基于第三方攻击的VoIP并联控制技术%The Research of VoIP Parallel Control Technology Based on Third-Party Attack

    Institute of Scientific and Technical Information of China (English)

    缪正洁

    2007-01-01

    随着VoIP的普及,对VoIP监测的需求愈加迫切,目前,传统的VoIP控制方式已无法满足现实的需要.文章简单介绍了VoIP基础,分析了VoIP信令流与媒体流交互的过程及VoIP传统的串联控制方式.在此基础上,分析和研究基于第三方攻击的VoIP并联控制方式,最后给出了并联控制方式下的VoIP控制系统模型及其在实际系统中的应用.

  16. 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

  17. AstroStat-A VO tool for statistical analysis

    Science.gov (United States)

    Kembhavi, A. K.; Mahabal, A. A.; Kale, T.; Jagade, S.; Vibhute, A.; Garg, P.; Vaghmare, K.; Navelkar, S.; Agrawal, T.; Chattopadhyay, A.; Nandrekar, D.; Shaikh, M.

    2015-06-01

    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 analyses are 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 them.

  18. What governs skeletal muscle VO2max? New evidence.

    Science.gov (United States)

    Richardson, R S

    2000-01-01

    Recent investigations into the determinants of skeletal muscle maximal oxygen consumption (VO2) have provided further evidence regarding the role of O2 supply and demand in governing exercise metabolism. Specifically, four studies utilizing both animal and human exercise models are highlighted here: 1) the role of the diffusive O2 component was examined in the exercising canine gastrocnemius muscle by a rightward shift in the O2 dissociation curve while maintaining O2 delivery constant; 2) the role of peripheral and central components was examined by studying the human quadriceps muscle, already recognized to have a very high mass specific O2 delivery, under conditions of increased (hyperoxia) and reduced O2 availability (hypoxia); 3) the role of intracellular PO2 in the progressive increase in lactate efflux from skeletal muscle from submaximal to maximal effort; and finally 4) the role of intracellular PO2 itself as a determinant of maximal mitochondrial O2 consumption. In summary, these investigations illustrate 1) the importance of the diffusion gradient from blood to muscle cell; 2) illustrate that even in functionally isolated trained skeletal muscle the highest recorded metabolic rates can be increased by increasing O2 supply; 3) that a constant intracellular PO2 during graded exercise is therefore unrelated to increasing lactate efflux; and 4) that only in hyperoxia does trained human skeletal muscle approaching very high mitochondrial metabolic limits, as shown by a disproportionate increase in intracellular PO2 for the recorded change in VO2max. PMID:10647536

  19. 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)

  20. 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 ...

  1. Pressure-induced phase transitions and metallization in VO2

    Science.gov (United States)

    Bai, Ligang; Li, Quan; Corr, Serena A.; Meng, Yue; Park, Changyong; Sinogeikin, Stanislav V.; Ko, Changhyun; Wu, Junqiao; Shen, Guoyin

    2015-03-01

    We report the results of pressure-induced phase transitions and metallization in VO2 based on synchrotron x-ray diffraction, electrical resistivity, and Raman spectroscopy. Our isothermal compression experiments at room temperature and 383 K show that the room temperature monoclinic phase (M 1 ,P 21/c ) and the high-temperature rutile phase (R ,P 42/m n m ) of VO2 undergo phase transitions to a distorted M 1 monoclinic phase (M 1' ,P 21/c ) above 13.0 GPa and to an orthorhombic phase (CaCl2-like, P n n m ) above 13.7 GPa, respectively. Upon further compression, both high-pressure phases transform into a new phase (phase X ) above 34.3 and 38.3 GPa at room temperature and 383 K, respectively. The room temperature M 1 -M 1' phase transition structurally resembles the R -CaCl2 phase transition at 383 K, suggesting a second-order displacive type of transition. Contrary to previous studies, our electrical resistivity results, Raman measurements, as well as ab initio calculations indicate that the new phase X , rather than the M 1' phase, is responsible for the metallization under pressure. The metallization mechanism is discussed based on the proposed crystal structure.

  2. Estudio de centrales de biomasa a pequeña escala como fuente de energía en las zonas rurales de la región de Göttingen (Alemania)

    OpenAIRE

    Veinat Grimalt, Francisca

    2013-01-01

    Las plantas de digestión anaerobia de biomasa se presentan como una buena opción tanto para la valorización económica de purines como para la obtención de energía a partir de fuentes renovables produciendo biogás. Dicha producción se puede mejorar mediante la co-digestión de los purines con cosustratos agrícolas o agroindustriales. A partir de las anteriores premisas se ha desarrollado en la región alemana de Göttingen los denominados pueblos bioenergéticos. Los cuales con recursos locale...

  3. 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

    OpenAIRE

    Torrente Trujillo Armando; Gasca Cesar A.; Menjivar Juan Carlos

    2011-01-01

    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 ...

  4. 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.

  5. 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

  6. Estado del Arte del Uso del Gas de Gasificación Termoquímica de Biomasa(GG), en Motores de Combustión Interna Alternativos

    OpenAIRE

    Fonseca Gonzalez, Natalia Elizabeth

    2003-01-01

    El presente trabajo, desarrollado en el marco del Convenio de Cooperación educativa entre la ETSII - UPM y el Ciemat, se realiza con el fin de determinar líneas futuras de investigación y/o aplicación de la tecnología de gasificación termoquímica de biomasa integrada a motores de combustión interna alternativos (MCIA) para generación de potencia, motivados por la necesidad de reducir las emisiones contaminantes, aumentar el uso de las fuentes renovables de energía, reducir la dependencia econ...

  7. Efecto de la fertilización sobre la producción de biomasa y la absorción de nutrientes en Brachiaria decumbens y Brachiaria híbrido Mulato

    OpenAIRE

    Navajas Martínez, Víctor Manuel

    2011-01-01

    Los suelos utilizados para la actividad ganadera generalmente son de baja fertilidad y alta acidez, lo cual genera bajas productividades. Existen cultivares de pasto Brachiaria que se adaptan a dichas condiciones adversas, pero se desconoce su comportamiento en condiciones agroecológicas de Barrancabermeja, Santander. El objetivo de esta investigación fue evaluar el efecto de la fertilización sobre la producción de biomasa y la absorción de nutrientes por los pastos Brachiaria decumbens y ...

  8. Rendimiento de biomasa y aceite esencial de quimiotipos de Lippia alba (Mill.) N. E. Brown en respuesta a las prácticas agronómicas, y sus propiedades farmacológicas

    OpenAIRE

    Blanco, Marcos

    2014-01-01

    Esta tesis estudia experimentalmente la respuesta de plantas cultivadas pertenecientes a cuatro quimiotipos de Lippia alba (carvona, dihidrocarvona, citral y linalol) ante la implementación de distintas técnicas de manejo agronómico. Se analizó la incidencia de la distancia de plantación y época de corte de la planta sobre el rendimiento de biomasa, de droga cruda (hoja seca) y aceite esencial en los diferentes quimiotipos evaluados. El rendimiento de droga cruda no fue afectado por las difer...

  9. Valorización de derivados de biomasa: producción de levulinato de etilo con bajo impacto ambiental empleando un heteropoliácido de estuctura Preyssler

    OpenAIRE

    Pasquale, Gustavo Antonio; Ruiz, Diego Manuel; Sathicq, Ángel Gabriel; Baronetti, Graciela T.; Gustavo P. Romanelli

    2015-01-01

    El ácido levulínico (LA), derivado de la catálisis ácida de la biomasa lignocelulósica, uno de los pilares del top-twelve building blocks, es potencialmente una molécula versátil para la síntesis de sustancias químicas para aplicaciones como aditivos de combustibles, precursores de polímeros y resinas. Por ejemplo, el levulinato de etilo (EL), obtenido por esterificación del LA con etanol, puede utilizarse como un aditivo en combustibles.Por otro lado, los procesos catalíticos utilizando hete...

  10. Obtención de un hidrolizado detoxificado a partir de biomasa lignocelulósica de Panicum maximum para su uso como sustrato en la fermentación alcohólica

    OpenAIRE

    Castillo Saldarriaga, Carlos Rafael

    2014-01-01

    El objetivo de esta investigación fue estudiar el efecto de una alta concentración de sólidos en la etapa de pretratamiento e hidrólisis enzimática empleando como materia prima biomasa lignocelulósica de Panicum maximum. Posteriormente, se evaluaron dos tratamientos de detoxificación de hidrolizados con el objetivo de ser usados como sustrato para la producción de etanol. Como pretratamiento se seleccionó ácido sulfúrico diluido. Las condiciones de pretratamiento evaluadas fueron: concentraci...

  11. The Effect of Aging on Relationships between Lean Body Mass and VO2max in Rowers

    Science.gov (United States)

    Kim, Chul-Ho

    2016-01-01

    Aging is associated with a fall in maximal aerobic capacity as well as with a decline in lean body mass. The purpose of the study was to investigate the influence of aging on the relationship between aerobic capacity and lean body mass in subjects that chronically train both their upper and lower bodies. Eleven older rowers (58±5 yrs) and 11 younger rowers (27±4 yrs) participated in the study. Prior to the VO2max testing, subjects underwent a dual energy X-ray absorptiometry scan to estimate total lean body mass. Subsequently, VO2max was quantified during a maximal exercise test on a rowing ergometer as well as a semi-recumbent cycle ergometer. The test protocol included a pre-exercise stage followed by incremental exercise until VO2max was reached. The order of exercise modes was randomized and there was a wash-out period between the two tests. Oxygen uptake was obtained via a breath-by-breath metabolic cart (Vmax™ Encore, San Diego, CA). Rowing VO2max was higher than cycling VO2max in both groups (p0.05), however, older subjects still demonstrated a lower rowing VO2max relative to younger subjects (p<0.05). Muscle mass is associated with the VO2max obtained, however, it appears that VO2max in older subjects may be less influenced by muscle mass than in younger subjects. PMID:27479009

  12. Submaximal Treadmill Exercise Test to Predict VO[subscript 2]max in Fit Adults

    Science.gov (United States)

    Vehrs, Pat R.; George, James D.; Fellingham, Gilbert W.; Plowman, Sharon A.; Dustman-Allen, Kymberli

    2007-01-01

    This study was designed to develop a single-stage submaximal treadmill jogging (TMJ) test to predict VO[subscript 2]max in fit adults. Participants (N = 400; men = 250 and women = 150), ages 18 to 40 years, successfully completed a maximal graded exercise test (GXT) at 1 of 3 laboratories to determine VO[subscript 2]max. The TMJ test was completed…

  13. 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.

  14. Occurrence of Siliceous Impact Melt in Netschaëvo IIE? A FIB-TEM Study

    Science.gov (United States)

    Hamann, C.; Van Roosbroek, N.; Greshake, A.; Pittarello, L.; Hecht, L.; Debaille, V.; Wirth, R.; Claeys, Ph.

    2015-07-01

    A silicate inclusion in a sample of the Netschaëvo IIE iron meteorite was studied with FIB-TEM. We present petrographic features indicating that this inclusion is quenched impact melt and suggest that Netschaëvo is an impact melt breccia.

  15. 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. PMID:26851474

  16. Synthesis and physicochemical investigation of CsUO2(VO3)3

    International Nuclear Information System (INIS)

    Compound CsUO2(VO3)3 is prepared by reaction in solid phase. Polymorphic transformation and properties of the compound are studied using the methods of high-temperature X-ray diffraction, IR spectroscopy and thermal analysis. Formation enthalpy of α-CsUO2(VO3)3 is determined by the method of adiabatic reaction calorimetry

  17. Pt/VO{sub 2} double-layered films combining thermochromic properties with low emissivity

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Litao; Du, Jing; Zhang, Zongtao [Research Center for Industrial Ceramics, Shanghai Institute of Ceramics (SIC), Chinese Academy of Sciences (CAS), Dingxi 1295, Changning, Shanghai 200050 (China); Graduate University of Chinese Academy of Sciences, Yuquanlu 19, Beijing 100049 (China); Gao, Yanfeng; Luo, Hongjie [Research Center for Industrial Ceramics, Shanghai Institute of Ceramics (SIC), Chinese Academy of Sciences (CAS), Dingxi 1295, Changning, Shanghai 200050 (China); Chen, Zhang [Research Center for Industrial Ceramics, Shanghai Institute of Ceramics (SIC), Chinese Academy of Sciences (CAS), Dingxi 1295, Changning, Shanghai 200050 (China); School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi' an 710021 (China)

    2010-12-15

    This study involves the optical properties of Pt/VO{sub 2} composite films, with a Pt top layer and a VO{sub 2} bottom layer. VO{sub 2} and Pt films were grown on fused silica substrates by polymer-assisted deposition and sputtering, respectively. These Pt/VO{sub 2} films were characterized by scanning electron microscopy, UV-visible-NIR spectrophotometry, Fourier transform infrared spectrometry, four-point probe and Raman spectroscopy. The results indicate that these Pt/VO{sub 2} films can enhance the infrared reflectivity while retaining their thermochromic properties. Although the visible transmittance is depressed by these Pt layers, the addition of antireflection coatings boosts the transmittance from 25.1% to 37.9% at 0.55 {mu}m. In addition, the semiconductor-metal (S-M) transition temperatures of Pt/VO{sub 2} films shift to lower temperatures in the heating semicycle (T{sub c,h}), from 67.8 C for a pure VO{sub 2} film to 58.5 C for a VO{sub 2} film covered with a 9 nm Pt layer. This work provides an important prototype structure for the development of new smart windows that combine thermochromic properties with low emissivity. (author)

  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. 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...

  20. The Effect of Aging on Relationships between Lean Body Mass and VO2max in Rowers.

    Science.gov (United States)

    Kim, Chul-Ho; Wheatley, Courtney M; Behnia, Mehrdad; Johnson, Bruce D

    2016-01-01

    Aging is associated with a fall in maximal aerobic capacity as well as with a decline in lean body mass. The purpose of the study was to investigate the influence of aging on the relationship between aerobic capacity and lean body mass in subjects that chronically train both their upper and lower bodies. Eleven older rowers (58±5 yrs) and 11 younger rowers (27±4 yrs) participated in the study. Prior to the VO2max testing, subjects underwent a dual energy X-ray absorptiometry scan to estimate total lean body mass. Subsequently, VO2max was quantified during a maximal exercise test on a rowing ergometer as well as a semi-recumbent cycle ergometer. The test protocol included a pre-exercise stage followed by incremental exercise until VO2max was reached. The order of exercise modes was randomized and there was a wash-out period between the two tests. Oxygen uptake was obtained via a breath-by-breath metabolic cart (Vmax™ Encore, San Diego, CA). Rowing VO2max was higher than cycling VO2max in both groups (prowing (p0.05), however, older subjects still demonstrated a lower rowing VO2max relative to younger subjects (p<0.05). Muscle mass is associated with the VO2max obtained, however, it appears that VO2max in older subjects may be less influenced by muscle mass than in younger subjects. PMID:27479009

  1. 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.

  2. Diseño y contraste de nuevos modelos de estimación del potencial energético de biomasa forestal en el Territorio de Bizkaia mediante técnicas de análisis estadístico espacial usando herramientas GIS con datos LiDAR

    OpenAIRE

    Torre Tojal, Leyre

    2016-01-01

    RESUMEN: El objetivo de esta tesis doctoral es desarrollar un modelo que permita estimar la biomasa aérea para la especie Pinus radiata en la comarca de Arratia-Nervión, (Bizkaia), a partir del uso exclusivo de los datos del vuelo LiDAR realizado por Gobierno Vasco en 2012. En el proceso, se han utilizado los datos de campo del Inventario Forestal Nacional 4 como base para estimar la biomasa de contraste. Partiendo de las nubes de puntos LiDAR y tras su procesado, se han calculado diversa...

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

    Science.gov (United States)

    Sousa, Ana C.; Vilas-Boas, João P.; Fernandes, Ricardo J.

    2014-01-01

    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. PMID:25045690

  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. 热致变色材料VO2的掺杂改性研究%THE STUDY ON MODIFICATION OF THERMOCHROMIC MATERIAL VO2

    Institute of Scientific and Technical Information of China (English)

    刘友文; 曾元媛; 沈毅

    2011-01-01

    VO2 is an excellent thermochromic material, in the heat electric switches, optical storage media and laser protective aspects have a broad prospect. So, people have a lot of work to study the thermochromic property of VO2, and doping is an effective method to improve the thermochromic. The paper reviews some research of doping VO2, and the future development trend is also put forward.%二氧化钒(VO2)是一种性能优异的热致变色材料,在热电开关、光存储介质和激光保护等方面有广泛的应用前景,因此,人们做了许多工作来研究VO2>的热致变色性能,而用离子掺杂是一种提高其热致变色性能的有效手段.本文综述了目前国内外一些掺杂VO2的研究成果,并对其发展趋势进行了简要分析.

  6. Microstructures and thermochromic properties of tungsten doped vanadium oxide film prepared by using VO{sub X}-W-VO{sub X} sandwich structure

    Energy Technology Data Exchange (ETDEWEB)

    Luo Zhenfei, E-mail: zhfluo@yahoo.com.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Wu Zhiming, E-mail: zmwu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China); Xu Xiangdong; Du Mingjun; Wang Tao; Jiang Yadong [State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054 (China)

    2011-05-25

    Tungsten doped vanadium oxide (VO{sub X}) thin films were prepared by oxygen annealing VO{sub X}-W-VO{sub X} sandwich layers. X-ray photoelectron spectroscopy, X-ray diffraction and field emission scanning electron microscope were employed to characterize the compositions, crystal structures and surface morphologies, respectively. It was demonstrated that sandwich structure suppressed the crystallization of VO{sub X}, and that V{sup 5+} was reduced by diffused W atom to V{sup 4+}. The results of surface morphologies indicated that the grain arrangement of W doped vanadium dioxide film exhibited some regular patterns compared with the random grain distribution of undoped film. Electrical measurements showed that the square resistance of V{sub 2}O{sub 5} film and semiconductor-metal transition temperature of VO{sub 2}-V{sub 2}O{sub 5} film decreased obviously after W doping. In addition, thermal hysteresis loop was observed in W doped V{sub 2}O{sub 5} film with thick W middle layer. The investigation of optical properties indicated that the optical band gap of W doped V{sub 2}O{sub 5} film decreased with the increase of thickness of W middle layer, and the optical switching performance in the near-infrared range of VO{sub 2}-V{sub 2}O{sub 5} slightly weakened after W doping.

  7. Silica-shell encapsulation and adhesion of VO2 nanowires to glass substrates: integrating solution-derived VO2 nanowires within thermally responsive coatings

    Science.gov (United States)

    Pelcher, Kate E.; Crawley, Matthew R.; Banerjee, Sarbajit

    2014-09-01

    The binary vanadium oxide VO2 undergoes a reversible insulator—metal phase transition in response to increasing temperature accompanied by an orders of magnitude alteration of optical transmittance; the low-temperature monoclinic phase of VO2 is infrared-transmissive, whereas the high-temperature rutile phase is infrared-reflective. This remarkable property portends applications in thermally responsive spectral mirrors that can modulate infrared transmittance as a function of temperature. Using a modified Stöber process, we demonstrate the constitution of conformal SiO2 shells around the VO2 nanowires. The SiO2 shells enhance the robustness of the VO2 nanowires towards thermal oxidation; the thickness of the shells is observed to depend on the reaction time. Notably, the deposition of conformal shells does not deleteriously impact the metal—insulator transitions of the VO2 nanowire cores. A modification of this approach allows for the VO2 nanowires to be embedded within a SiO2 matrix bonded to glass. The applied coatings are strongly adhered to glass as evaluated using standardized ASTM methods. The coatings exhibit promising thermochromic response and attenuate transmission of near-infrared radiation with increasing temperature.

  8. 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.

  9. 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.

  10. 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.

  11. Selective growth of single phase VO{sub 2}(A, B, and M) polymorph thin films

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Amar; Saha, Surajit [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Rotella, Helene [NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Pal, Banabir [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India); Kalon, Gopinadhan; Mathew, Sinu; Motapothula, Mallikarjuna; Dykas, Michal [NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Yang, Ping [Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Okunishi, Eiji [Electron Optics Division, JEOL Ltd., Tokyo 196-8558 (Japan); Sarma, D. D. [Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012 (India); Council of Scientific and Industrial Research-Network of Institutes for Solar Energy (CSIR-NISE), New Delhi 110001 (India); Venkatesan, T., E-mail: venky@nus.edu.sg [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); NUSNNI-NanoCore, National University of Singapore, Singapore 117576 (Singapore); Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore)

    2015-02-01

    We demonstrate the growth of high quality single phase films of VO{sub 2}(A, B, and M) on SrTiO{sub 3} 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 VO{sub 2} and their electronic properties are investigated. VO{sub 2}(A) phase is insulating VO{sub 2}(B) phase is semi-metallic, and VO{sub 2}(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 (hetero)structures promising new device functionalities.

  12. Crystal Structure and Spectroscopic Properties of CsVO2SO4

    DEFF Research Database (Denmark)

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

    2004-01-01

    in the orthorhombic space group Pbca with a = 6.6688(13) Angstrom, b = 10.048(2) Angstrom, and c = 17.680(4) Angstrom at 20 degreesC and Z = 8. It contains a coordination sphere with a short V-O bond of 1.595(2) Angstrom and trans to this the closest VO distance at 3.4 Angstrom and four equatorial V-O bonds...... 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...

  13. Evaluating the perceived voice quality on VoIP network using interpolated FIR filter algorithm

    Science.gov (United States)

    Pal Singh, Harjit; Singh, Sarabjeet; Sarin, R. K.; Singh, Jasvir

    2012-10-01

    Voice over Internet Protocol (VoIP) is a popular communication service nowadays. VoIP reduces the cost of call transmission by passing voice and video packets through the available bandwidth for data packets through Internet protocol. The quality of the VoIP signal is degraded due to the various network impairments. The proposed scheme, interpolated finite impulse response, is implemented as post-processor after decoding the signal in VoIP system. The performance of the proposed scheme is evaluated for various network conditions. The results of the proposed scheme are measured with the objective measurement methods for signal quality evaluation. The performance of the proposed system is compared with the existing techniques for quality improvement in VoIP system. The results show much improvement in speech quality with the proposed scheme in comparison to other similar schemes.

  14. VoIP网络电话技术及其应用%VOIP Network Telephony and Its Application

    Institute of Scientific and Technical Information of China (English)

    魏迎春; 高电波; 王利群

    2003-01-01

    介绍了VoIP网络电话出现的背景产生及优势;讨论了VoIP通信网络的体系结构;研究了局域网PBX的体系结构及特征;分析了VoIP网络电话的信令协议;介绍了VoIP网络电话技术的应用及其特点.

  15. Time to Exhaustion at the VO2max Velocity in Swimming: A Review

    Science.gov (United States)

    Fernandes, Ricardo J.; Vilas-Boas, J. Paulo

    2012-01-01

    The aim of this study was to present a review on the time to exhaustion at the minimum swimming velocity corresponding to maximal oxygen consumption (TLim-vVO2max). This parameter is critical both for the aerobic power and the lactate tolerance bioenergetical training intensity zones, being fundamental to characterize it, and to point out its main determinants. The few number of studies conducted in this topic observed that swimmers were able to maintain an exercise intensity corresponding to maximal aerobic power during 215 to 260 s (elite swimmers), 230 to 260 s (high level swimmers) and 310 to 325 s (low level swimmers), and no differences between genders were reported. TLim-vVO2max main bioenergetic and functional determinants were swimming economy and VO2 slow component (direct relationship), and vVO2max, velocity at anaerobic threshold and blood lactate production (inverse relationship); when more homogeneous groups of swimmers were analysed, the inverse correlation value between TLim-vVO2max and vVO2max was not so evident. In general, TLim-vVO2max was not related to VO2max. TLim-vVO2max seems also to be influenced by stroking parameters, with a direct relationship to stroke length and stroke index, and an inverse correlation with stroke rate. Assessing TLim-vVO2max, together with the anaerobic threshold and the biomechanical general parameters, will allow a larger spectrum of testing protocols application, helping to build more objective and efficient training programs. PMID:23486651

  16. Preparation and thermochromic properties of Ce-doped VO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Song, Linwei [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Zhang, Yubo [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Sichuan Engineering Technical College, Deyang 618000 (China); Huang, Wanxia, E-mail: huangwanxiascu@yahoo.com.cn [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China); Shi, Qiwu; Li, Danxia; Zhang, Yang; Xu, Yuanjie [College of Materials Science and Engineering, Sichuan University, Chengdu 610064 (China)

    2013-06-01

    Graphical abstract: This effect of doping concentration on the phase transition temperature of VO{sub 2} films demonstrates that the phase transition temperature is decreasing along with the increase of the Ce dopant concentrations. After doping Ce, the transition temperature of VO{sub 2} film changes appreciably. Highlights: ► Ce-doped VO{sub 2} films were prepared on muscovite substrate by inorganic sol–gel method for the first time. ► The cerium existing in the VO{sub 2} films in the form of Ce{sup 4+} and Ce{sup 3+} was substituted for part of V atoms in the lattice. ► Ce doping could remarkably reduce the particle size of the Ce-doped films compared with undoped films. ► The phase transition temperature of Ce-doped VO{sub 2} films decreased appreciably with maintaining high-quality phase transition. - Abstract: Mixture of cerium (III) nitrate hexahydrate and vanadium pentaoxide powder were used as precursor to prepare Ce-doped VO{sub 2} films on the muscovite substrate by inorganic sol–gel method. SEM, XRD and XPS were used to investigate the morphologies and structures of VO{sub 2} films. The results show that the VO{sub 2} films grow on the muscovite substrate with preferred orientated (0 1 1) plane and the Ce exists in the form of Ce{sup 4+} and Ce{sup 3+} replacing part of V atoms in the lattice. The infrared transmittance change was measured from room temperature to the temperature above the metal–insulator transition. The films have excellent thermochromic performance. The metal–insulator transition temperature of VO{sub 2} films changes appreciably with Ce doped, which decreases by 4.5 °C per 1 at.% doping. Furthermore, Ce doping could remarkably reduce the particle size of VO{sub 2} films.

  17. VO2 Off Transient Kinetics in Extreme Intensity Swimming

    Science.gov (United States)

    Sousa, Ana; Figueiredo, Pedro; Keskinen, Kari L.; Rodríguez, Ferran A.; Machado, Leandro; Vilas-Boas, João P.; Fernandes, Ricardo J.

    2011-01-01

    Inconsistencies about dynamic asymmetry between the on- and off- transient responses in oxygen uptake are found in the literature. Therefore, the purpose of this study was to characterize the oxygen uptake off-transient kinetics during a maximal 200-m front crawl effort, as examining the degree to which the on/off regularity of the oxygen uptake kinetics response was preserved. Eight high level male swimmers performed a 200-m front crawl at maximal speed during which oxygen uptake was directly measured through breath-by-breath oxymetry (averaged every 5 s). This apparatus was connected to the swimmer by a low hydrodynamic resistance respiratory snorkel and valve system. Results: The on- and off-transient phases were symmetrical in shape (mirror image) once they were adequately fitted by a single-exponential regression models, and no slow component for the oxygen uptake response was developed. Mean (± SD) peak oxygen uptake was 69.0 (± 6.3) mL·kg-1·min-1, significantly correlated with time constant of the off- transient period (r = 0.76, p < 0.05) but not with any of the other oxygen off-transient kinetic parameters studied. A direct relationship between time constant of the off-transient period and mean swimming speed of the 200-m (r = 0.77, p < 0.05), and with the amplitude of the fast component of the effort period (r = 0.72, p < 0.05) were observed. The mean amplitude and time constant of the off-transient period values were significantly greater than the respective on- transient. In conclusion, although an asymmetry between the on- and off kinetic parameters was verified, both the 200-m effort and the respectively recovery period were better characterized by a single exponential regression model. Key points The VO2 slow component was not observed in the recovery period of swimming extreme efforts; The on and off transient periods were better fitted by a single exponential function, and so, these effort and recovery periods of swimming extreme efforts are

  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. Performability Aspects of the Atlas Vo; Using Lmbench Suite

    CERN Document Server

    Georgatos, Fotis; Kouretis, John

    2008-01-01

    The ATLAS Virtual Organization is grid's largest Virtual Organization which is currently in full production stage. Hereby a case is being made that a user working within that VO is going to face a wide spectrum of different systems, whose heterogeneity is enough to count as "orders of magnitude" according to a number of metrics; including integer/float operations, memory throughput (STREAM) and communication latencies. Furthermore, the spread of performance does not appear to follow any known distribution pattern, which is demonstrated in graphs produced during May 2007 measurements. It is implied that the current practice where either "all-WNs-are-equal" or, the alternative of SPEC-based rating used by LCG/EGEE is an oversimplification which is inappropriate and expensive from an operational point of view, therefore new techniques are needed for optimal grid resources allocation.

  20. 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.

  1. 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.

  2. 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%. PMID:27386565

  3. The VO-Dance web application at the IA2 data center

    Science.gov (United States)

    Molinaro, Marco; Knapic, Cristina; Smareglia, Riccardo

    2012-09-01

    Italian center for Astronomical Archives (IA2, http://ia2.oats.inaf.it) is a national infrastructure project of the Italian National Institute for Astrophysics (Istituto Nazionale di AstroFisica, INAF) that provides services for the astronomical community. Besides data hosting for the Large Binocular Telescope (LBT) Corporation, the Galileo National Telescope (Telescopio Nazionale Galileo, TNG) Consortium and other telescopes and instruments, IA2 offers proprietary and public data access through user portals (both developed and mirrored) and deploys resources complying the Virtual Observatory (VO) standards. Archiving systems and web interfaces are developed to be extremely flexible about adding new instruments from other telescopes. VO resources publishing, along with data access portals, implements the International Virtual Observatory Alliance (IVOA) protocols providing astronomers with new ways of analyzing data. Given the large variety of data flavours and IVOA standards, the need for tools to easily accomplish data ingestion and data publishing arises. This paper describes the VO-Dance tool, that IA2 started developing to address VO resources publishing in a dynamical way from already existent database tables or views. The tool consists in a Java web application, potentially DBMS and platform independent, that stores internally the services' metadata and information, exposes restful endpoints to accept VO queries for these services and dynamically translates calls to these endpoints to SQL queries coherent with the published table or view. In response to the call VO-Dance translates back the database answer in a VO compliant way.

  4. Terbium-Doped VO2 Thin Films: Reduced Phase Transition Temperature and Largely Enhanced Luminous Transmittance.

    Science.gov (United States)

    Wang, Ning; Duchamp, Martial; Dunin-Borkowski, Rafal E; Liu, Shiyu; Zeng, XianTing; Cao, Xun; Long, Yi

    2016-01-26

    Vanadium dioxide (VO2) is a well-known thermochromic material with large IR modulating ability, promising for energy-saving smart windows. The main drawbacks of VO2 are its high phase transition temperature (τ(c) = 68°C), low luminous transmission (T(lum)), and weak solar modulating ability (ΔT(sol)). In this paper, the terbium cation (Tb(3+)) doping was first reported to reduce τ(c) and increase T(lum) of VO2 thin films. Compared with pristine VO2, 2 at. % doping level gives both enhanced T(lum) and ΔT(sol) from 45.8% to 54.0% and 7.7% to 8.3%, respectively. The T(lum) increases with continuous Tb(3+) doping and reaches 79.4% at 6 at. % doping level, representing ∼73.4% relative increment compared with pure VO2. This has surpassed the best reported doped VO2 thin films. The enhanced thermochromic properties is meaningful for smart window applications of VO2 materials. PMID:26729057

  5. 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

  6. Preparation and characterization of fly ash cenospheres supported CuO–BiVO4 heterojunction composite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Novel CuO–BiVO4/FACs heterojunction composites have been synthesized. • CuO–BiVO4 are loaded on the surface of lightweight hollow microspheres. • The CuO–BiVO4/FACs exhibit enhanced absorption in the visible light region. • The CuO–BiVO4/FACs show efficient photocatalytic activities. • The composites are floatable and can be recovered easily. - Abstract: Novel fly ash cenospheres supported CuO–BiVO4 heterojunction composites (CuO–BiVO4/FACs) were prepared by modified metalorganic decomposition and impregnation methods. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectra (XPS), and UV–vis diffused reflectance spectroscopy (DRS) techniques. The XPS and SEM analyses indicated that Cu was present as CuO dispersed on the surface of BiVO4. The DRS spectra revealed that the composites had improved optical adsorption in the visible light region, and the composites exhibited enhanced photocatalytic activity for methylene blue (MB) degradation under visible light irradiation. It was found that the 5 wt% CuO-loaded composite showed the highest photocatalytic activity for MB dye wastewater treatment. FACs, a by-product generated in coal-firing power plants, were used as a low cost support which favored phase separation after the reaction owing to their low density

  7. 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.

  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. Transformiranje industrije kao odgovor na tranziciju gospodarstva - slučaj pekarske industrije u Rusiji

    OpenAIRE

    Smirnova, Maria; Rebiazina, Vera; Moreva, Irina

    2014-01-01

    Mnoga tranzicijska gospodarstva prošla su ili još uvijek prolaze značajne promjene. Ciljevi ovog rada jesu na primjeru pekarske industrije u Rusiji pružiti dublje razumijevanje i longitudinalnu perspektivu o tome kako se tranzicijski proces i institucionalne promjene u gospodarstvu odražavaju na napredak neke industrije. Promjene na razini industrije nisu vođene samo gospodarskom tranzicijom već i strateškim odlukama sudionika na tržištu. Te su odluke povezane s intenzitetom i prirodom natje...

  10. Validation of a Ramp Running Protocol for Determination of the True VO2max in Mice.

    Science.gov (United States)

    Ayachi, Mohamed; Niel, Romain; Momken, Iman; Billat, Véronique L; Mille-Hamard, Laurence

    2016-01-01

    In the field of comparative physiology, it remains to be established whether the concept of VO2max is valid in the mouse and, if so, how this value can be accurately determined. In humans, VO2max is generally considered to correspond to the plateau observed when VO2 no longer rises with an increase in workload. In contrast, the concept of VO2peak tends to be used in murine studies. The objectives of the present study were to determine whether (i) a continuous ramp protocol yielded a higher VO2peak than a stepwise, incremental protocol, and (ii) the VO2peak measured in the ramp protocol corresponded to VO2max. The three protocols (based on intensity-controlled treadmill running until exhaustion with eight female FVB/N mice) were performed in random order: (a) an incremental protocol that begins at 10 m.min(-1) speed and increases by 3 m.min(-1) every 3 min. (b) a ramp protocol with slow acceleration (3 m.min(-2)), and (c) a ramp protocol with fast acceleration (12 m.min(-2)). Each protocol was performed with two slopes (0 and 25°). Hence, each mouse performed six exercise tests. We found that the value of VO2peak was protocol-dependent (p 8 mmol.l(-1) and a respiratory exchange ratio >1). The total duration of the 3 m.min(-2) 0° ramp protocol was shorter than that of the incremental protocol. Taken as a whole, our results suggest that VO2max in the mouse is best determined by applying a ramp exercise protocol with slow acceleration and no treadmill slope. PMID:27621709

  11. Lithium-inserted vanadium dioxide (LixVO2) thin films

    Science.gov (United States)

    Khan, Mohammad S. R.

    1996-04-01

    Thermochromic switching between a low-temperature and high-temperature less transparent state is possible in thin films based on vanadium dioxide (VO2). The critical temperature Tc at which the transition takes place in VO2 is on the order of 68 degrees Celsius which can be depressed towards a comfortable temperature by several techniques, including dopants. Dopants can be inserted by electrochemical means. This work is an exploratory study of the electrochromism of LixVO2 with a view to 'smart window' applications. Thin films of LixVO2 (0 less than or equal to x less than or equal to 0.43) were made by reactive sputtering and annealing electrolyte of LiClO4 and propylene carbonate. A maximum lithium content of x equals 0.43 was accomplished. Optical spectral response at wavelength pertinent to solar radiation was reported. Lithium insertion increased the transmittance gradually and reversibly i.e. LixVO2 showed electrochromism and bleached under Li insertion. LixVO2 also showed thermochroism, although to a smaller degree than VO2 and was most transparent at low temperature. Temperature- dependent electrical conductivity and thermoelectric power measurements were also performed. A conductivity transition by approximately 3 orders of magnitude was seen at approximately 60 degrees Celsius in VO2. This transition decreased in proportion with the amount of Li intercalation and was less than one order of magnitude in Li0.43VO2. Lithiation also decreased Tc by a few degrees Celsius. The thermoelectric power showed a well defined increase when Tc was exceeded.

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

    Science.gov (United States)

    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.

  13. 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 (K4b2, 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. PMID:24404156

  14. DyVO4 thermal expansion anomalies caused by quadrupole ordering

    International Nuclear Information System (INIS)

    The experimental and theoretical studies on anomalies of the DyVO4 crystals thermal expansion, conditioned by ordering the Q2 quadrupole moments of the Dy3+ ion, are presented. The calculated curves sufficiently well describe the experiment both in the tetragonal and rhombic phases. The values of the complete quadrupole constant and magnetoelastic contribution to it are obtained for the DyVO4. It is noted, that the DyVO4 is the only crystal in the zircons family, for which the γ-symmetry quadrupole ordering is realized

  15. Probing electronic state at atomic scale on the surface of SrVO3 film

    Science.gov (United States)

    Okada, Yoshinori; Shimizu, Ryota; Shiraki, Susumu; Hitosugi, Taro

    2014-03-01

    Probing electronic structure of atomically well controlled surface of Perovskite-type 3d transition-metal oxides have been attracting much interest because of their intriguing emergent physical properties by heterostructure engineering. In this study, we have especially focused on SrVO3, where importance of correlation effects has been considered. We successfully obtained atomically flat surfaces of SrVO3, which gave us the great opportunity to visualize correlated electronic state at atomic scale by means of spectroscopic imaging scanning tunneling spectroscopy. Based on the experimental data, we discuss spectroscopic signature of many body effects on the surface of SrVO3 system.

  16. Synthesis and characterization of VO2-based thermochromic thin films for energy-efficient windows

    OpenAIRE

    Batista, C.; Ribeiro, R. M.; Teixeira, Vasco M. P.

    2011-01-01

    Thermochromic VO2 thin films have successfully been grown on SiO2-coated float glass by reactive DC and pulsed-DC magnetron sputtering. The influence of substitutional doping of V by higher valence cations, such as W, Mo, and Nb, and respective contents on the crystal structure of VO2 is evaluated. Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed. In summary, all the dopant elemen...

  17. VO2-based Thermochromic and Nanothermochromic Materials for Energy-Efficient Windows : Computational and Experimental Studies

    OpenAIRE

    Li, Shuyi

    2013-01-01

    VO2-based films are thermochromic and exhibit high or low infrared transmittance when the temperature is below or above a critical temperature. The thermochromic switching is passive and reversible, and therefore VO2 based films are promising for energy-efficient window appli­cations. However the practicaluse of VO2 for energy-efficient windows has long been hampered by low luminous transmittance and low solar energy transmittance modulation. The main goal of this dissertation work is to address ...

  18. Durability of VO 2 -based thin films at elevated temperature : Towards thermochromic fenestration

    OpenAIRE

    Ji, Yu-Xia; Niklasson, Gunnar A.; Granqvist, Claes-Göran

    2014-01-01

    An explorative study was performed on sputter-deposited thermochromic VO 2 films with top coatings of Al oxide and Al nitride. The films were exposed to dry air at a high temperature. Bare 80-nm-thick VO 2 films rapidly converted to non-thermochromic V 2 O 5 under the chosen conditions. Al oxide top coatings protected the underlying VO 2 films and, expectedly, increased film thickness yielded improved protection. Specifically, it was found that a 30-nm-thick sputter-deposited Al oxide top coa...

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

    OpenAIRE

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

    2016-01-01

    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...

  20. Impact of VoIP and QoS on Open and Distance Learning

    OpenAIRE

    JASOLA, Sanjay; Saxena, P.C.; Sharma, Ramesh C.

    2006-01-01

    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 be...

  1. VO2薄膜的制备工艺研究

    Institute of Scientific and Technical Information of China (English)

    卫红; 王小辉; 唐振方; 曹一鸣; 刘志宇

    2009-01-01

    采用射频磁控溅射沉积方法,在加热衬底上溅射制备高价态的五氧化二钒(V2O5)薄膜,再结合气氛退火工艺制备VO2薄膜.系统分析了不同溅射工艺参数和退火工艺参数对VO2薄膜结构与光电性能的影响,得到制备VO2薄膜的最佳工艺参数.

  2. User Access Control and Authentication System for VoIP Service in Mobile Communication Environments

    OpenAIRE

    Ho-Kyung Yang; Jeong-Kyung Moon; Cheol-Rim Choi; Hwang-Bin Ryou

    2014-01-01

    VoIP, which is used to transmit voice data on the Internet, is being welcomed as a replacement for the PSTN. In VoIP, voice data are converted to IP data and transmitted in an ordinary IP network. As a result, it is less expensive than the ordinary telephone network and has excellent scalability. With the increasing demand for VoIP services, problems are also occurring, namely, security vulnerabilities and degraded service quality. To address these issues, in this paper an AA (Attribute Autho...

  3. 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.

  4. 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.

  5. Equivalent circuit for VO2 phase change material film in reconfigurable frequency selective surfaces

    International Nuclear Information System (INIS)

    We developed equivalent circuits of phase change materials based on vanadium dioxide (VO2) thin films. These circuits are used to model VO2 thin films for reconfigurable frequency selective surfaces (FSSs). This is important as it provides a way for designing complex structures. A reconfigurable FSS filter using VO2 ON/OFF switches is designed demonstrating −60 dB isolation between the states. This filter is used to provide the transmission and reflection responses of the FSS in the frequency range of 0.1–0.6 THz. The comparison between equivalent circuit and full-wave simulation shows excellent agreement

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

    Directory of Open Access Journals (Sweden)

    Ana Sousa

    Full Text Available 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Vybrané aspekty významu hudby vo voľnom čase a jej pôsobenie na človeka

    OpenAIRE

    ŠUŤÁKOVÁ, Veronika

    2014-01-01

    This thesis deals about theme of music in leisure and its effects on humans. The first chapter is describing about music in history. The second chapter deals about the pop music, using music in leisure and about the media which are producing music and spreading it among the people. The last third chapter discusses about the effect of music on humans. Effects are noxious or therapeutic. In the practical part we were examining and describing the perception of healthy and unhealthy music by peop...

  12. 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

  13. 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. 

  14. 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...

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

    Science.gov (United States)

    Watzlaf, Valerie R.; Ondich, Briana

    2012-01-01

    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 clients/consumers. PMID:25945194

  16. Roles of grain boundaries on the semiconductor to metal phase transition of VO2 thin films

    International Nuclear Information System (INIS)

    Vanadium dioxide (VO2) thin films with controlled grain sizes are deposited on amorphous glass substrates by pulsed laser deposition. The grain boundaries (GBs) are found as the dominating defects in the thin films. The semiconductor to metal transition (SMT) properties of VO2 thin films are characterized and correlated to the GB density. The VO2 films with lower GB density exhibit a sharper SMT with a larger transition amplitude. A high resolution TEM study at GB area reveals the disordered atomic structures along the boundaries and the distorted crystal lattices near the boundaries. The VO2 SMT amplitude and sharpness could be directly related to these defects at and near the boundaries

  17. High-temperature behavior of vanadyl pyrophosphate (VO)2P2O7

    International Nuclear Information System (INIS)

    (VO)2P2O7 has been studied at high temperatures by in situ X-ray powder diffraction in an inert atmosphere. Lattice parameters indicate an anisotropic thermal expansion up to Tc=214-bar C, followed by an approximately isotropic expansion up to 490-bar C. It is proposed that Tc is the temperature of a second-order phase transition between the known room temperature form with space group Pca21 and a high-temperature form with space group Pcab. Above 490-bar C a minority phase develops in the sample that was identified as the V3+ containing compound V4(P2O7)3, while the anisotropic expansion along a suggests that stoichiometric (VO)2P2O7 transforms into (VO)2P2O7+x with interstitial oxygen located between the layers. With an onset at 706-bar C all of the (VO)2P2O7 transforms into VPO4

  18. 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...

  19. 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

    Abstract Objective. Aerobic fitness, defined as maximum oxygen uptake (VO(2PEAK)), and body fat measurements represent two known risk factors for disease. The purpose of this study was to investigate the relationship between VO(2PEAK) and body fat measurements in young children at a population......-based level. Methods. Cross-sectional study of 225 children (128 boys and 97 girls) aged 8-11 years, recruited from a population-based cohort. Total lean body mass (LBM), total fat mass (TBF), and abdominal fat mass (AFM) were measured by dual-energy x-ray absorptiometry. Body fat was also calculated...... 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...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Nanothermochromics with VO2-based core-shell structures : Calculated luminous and solar optical properties

    OpenAIRE

    Li, Shuyi; Niklasson, Gunnar A.; Granqvist, Claes-Göran

    2011-01-01

    Composites including VO2-based thermochromic nanoparticles are able to combine high luminous transmittance T-lum with a significant modulation of the solar energy transmittance Delta T-sol at a "critical" temperature in the vicinity of room temperature. Thus nanothermochromics is of much interest for energy efficient fenestration and offers advantages over thermochromic VO2-based thin films. This paper presents calculations based on effective medium theory applied to dilute suspensions of cor...

  7. Effect of Free Bandwidth on VoIP Performance in 802.11b WLAN Networks

    OpenAIRE

    Narbutt, Miroslaw; Davis, Mark

    2006-01-01

    In this paper we experimentally study the relationship between bandwidth utilization in the wireless LAN and the quality of VoIP calls transmitted over the wireless medium. Specifically we evaluate how the amount of free bandwidth decreases as the number of calls increases and how this influences transmission impairments (i.e. delay, loss and jitter) and thus degrades call quality. We show that the amount of free bandwidth is a good indicator for predicting VoIP call quality.

  8. Gauging VoIP Call Quality from 802.11 WLAN Resource Usage

    OpenAIRE

    Narbutt, Miroslaw; Davis, Mark

    2006-01-01

    In this paper we experimentally study the relationship between resource utilization in the wireless LAN and the quality of VoIP calls transmitted over the wireless medium. Specifically we evaluate how its overall capacity is shared between three basic MAC bandwidth components (load, access and free) as the number of VoIP calls increases and how it influences transmission impairments (delay, loss and jitter) and thus call quality. Resource utilization (under the MAC bandwidth components framew...

  9. QoS Analysis for Signaling in VoIP Client and Server Communication for Multicore

    OpenAIRE

    Adnan, Muhammad

    2012-01-01

    Due to the cost-effective solutions provided by Voice over Internet Protocol (VoIP) technology to enterprises and individuals, the growth has been significantly high in this area during the past and current decade. The growing demand has resulted in the escalating number of users who need secure, reliable and efficient communication systems. The deployment of multicore hardware has been solving the computational complexity problems. A multicore hardware/software model for VoIP is the key rese...

  10. VoIP Performance Analysis over IPv4 and IPv6

    OpenAIRE

    Monjur Ahmed; Alan T Litchfield; Shakil Ahmed; Adnan Mahmood; Md. Emran Hossain Meazi

    2014-01-01

    The advance of technology often requires the emergence of complementary technologies, of which the transition from IPv4 to IPv6 presents a significant example. The move of protocol has focussed attention on the level of performance for associated technologies. Among the many Internet applications, in contemporary digital communications, VoIP stands apart in importance. This paper presents a performance analysis of VoIP using IPv4 and IPv6. Using OPNET to simulate the protocols and to investig...

  11. A novel approach for security issues in VoIP networks in Virtualization with IVR

    OpenAIRE

    Kinjal Shah; Satya Prakash Ghrera; Alok Thaker

    2012-01-01

    VoIP (Voice over Internet Protocol) is a growing technology during last decade. It provides the audio, video streaming facility on successful implementation in the network. However, it provides the text transport facility over the network. Due to implementation of it the cost effective solution, it can be developed for the intercommunication among the employees of a prestigious organization. The proposed idea has been implemented on the audio streaming area of the VoIP technology. In the ...

  12. A Model for Emergency Service of VoIP Through Certification and Labeling

    OpenAIRE

    Douglas Sicker; Tom Lookabaugh

    2004-01-01

    Voice over Internet Protocol (VoIP) will transform many aspects of traditional telephony service including technology, the business models and the regulatory constructs that govern such service. This transformation is generating a host of technical, business, social and policy problems. The Federal Communications Commission (FCC) could attempt to mandate obligations or specific solutions to the policy issues around VoIP, but is instead looking first to industry initiatives focused on key func...

  13. SDN-Driven Multicast Streams with Adaptive Bitrates for VoIP Conferences

    OpenAIRE

    Al Hasrouty, Christelle; Autefage, Vincent; Olariu, Cristian; Magoni, Damien; Murphy, John

    2016-01-01

    Achieving high-quality voice conference calls over the Internet is a difficult task. Heterogeneous mobile devices and network dynamics must be properly managed by multiparty VoIP systems to ensure a good quality of experience. In this paper, we propose a multiparty VoIP system based on SDN technology that uses both multicast distribution and dynamic stream adaptation to optimize the conference call quality for each participant. We define a tree construction algorithm that includes two modes: ...

  14. Evaluation and Investigation of the Delay in VoIP Networks

    Directory of Open Access Journals (Sweden)

    V. Janata

    2011-06-01

    Full Text Available The paper is focused mainly on the delay problems, which considerably influence the final quality of connections in VoIP (Voice over IP networks. The paper provides a detailed exploration of the nature and mechanisms of the delay. The main purpose of the investigation was an attempt to formulate a mathematical model of delay in the VoIP network and its subsequent analysis by laboratory data.

  15. C4v Symmetry Crystal Field and Ground State Wavefunction of the VO2+ Ion

    Institute of Scientific and Technical Information of China (English)

    Ram Kripal; Santwana Shukla

    2009-01-01

    The spin-Hamiltonian parameters obtained from EPR studies of the VO2+ ion in different diamagnetic host lattices are used to estimate the ground state wavefunctions.These are of dxy type with admixture of the excited states dx2-y2,dyz and dxz.The hyperfine interaction parameter and Fermi contact term for the VO2+ doped crystals are determined using the coefficients of the ground state.The various parameters are correlated to the ligand properties of the complexes.

  16. Voltage-controlled switching and thermal effects in VO{sub 2} nano-gap junctions

    Energy Technology Data Exchange (ETDEWEB)

    Joushaghani, Arash; Jeong, Junho; Stewart Aitchison, J.; Poon, Joyce K. S. [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Paradis, Suzanne; Alain, David [Defence Research and Development Canada - Valcartier, 2459 Pie-XI Blvd. North, Quebec, Quebec G3J 1X5 (Canada)

    2014-06-02

    Voltage-controlled switching in lateral VO{sub 2} nano-gap junctions with different gap lengths and thermal properties was investigated. The effect of Joule heating on the phase transition was found to be strongly influenced by the device geometry, the contact material, and the current. Our results indicate that the VO{sub 2} phase transition was likely initiated electronically, which was sometimes followed by a secondary thermally induced transition.

  17. Voltage-controlled switching and thermal effects in VO2 nano-gap junctions

    International Nuclear Information System (INIS)

    Voltage-controlled switching in lateral VO2 nano-gap junctions with different gap lengths and thermal properties was investigated. The effect of Joule heating on the phase transition was found to be strongly influenced by the device geometry, the contact material, and the current. Our results indicate that the VO2 phase transition was likely initiated electronically, which was sometimes followed by a secondary thermally induced transition.

  18. 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...

  19. 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..

  20. Self-Assembly and Horizontal Orientation Growth of VO2 Nanowires

    OpenAIRE

    Chun Cheng; Hua Guo; Abbas Amini; Kai Liu; Deyi Fu; Jian Zou; Haisheng Song

    2014-01-01

    Single-crystalline vanadium dioxide (VO2) nanostructures have attracted an intense research interest recently because of their unique single-domain metal-insulator phase transition property. Synthesis of these nanostructures in the past was limited in density, alignment, or single-crystallinity. The assembly of VO2 nanowires (NWs) is desirable for a “bottom-up” approach to the engineering of intricate structures using nanoscale building blocks. Here, we report the successful synthesis of hori...

  1. Optimization of the annealing conditions for thin VO2 ALD films

    OpenAIRE

    Rampelberg, Geert; Schaekers, Marc; Deduytsche, Davy; De Schutter, Bob; Kittl, Jorge; Detavernier, Christophe

    2012-01-01

    Vanadium dioxide (VO2) is an intriguing material due to its semiconductor-metal transition (SMT). During this transition, which occurs near 67°C, electrical as well as optical properties change drastically. Possible applications include thermochromic windows, and memories or switches in micro- and optoelectronics. Although atomic layer deposition (ALD) is gaining importance for some of these applications, the growth of VO2 with this technique is not obvious, since in most cases V2O5 is obtain...

  2. Semiconductor-metal transition in thin VO2 films grown by ozone based atomic layer deposition

    OpenAIRE

    Rampelberg, Geert; Schaekers, Marc; Martens, Koen; Xie, Qi; Deduytsche, Davy; De Schutter, Bob; Blasco, Nicolas; Kittl, Jorge; Detavernier, Christophe

    2011-01-01

    Vanadium dioxide (VO2) has the interesting feature that it undergoes a reversible semiconductor-metal transition (SMT) when the temperature is varied near its transition temperature at 68°C.1 The variation in optical constants makes VO2 useful as a coating material for e.g. thermochromic windows,2 while the associated change in resistivity could be interesting for applications in microelectronics, e.g. for resistive switches and memories.3 Due to aggressive scaling and increasing integration ...

  3. Slowed Exercise-Onset Vo(2) Kinetics During Submaximal Endurance Exercise in Subjects With Multiple Sclerosis

    OpenAIRE

    Hansen, Dominique; Wens, Inez; KOSTEN, Lauren; Verboven, Kenneth; Eijnde, Bert O

    2013-01-01

    Background. Low physical activity levels in persons with multiple sclerosis (MS) may reduce skeletal muscle oxidative capacity. Rehabilitation strategies might be altered by a measure of capacity that did not require invasive techniques or maximal exercise testing. For this purpose, we measured exercise onset and offset oxygen uptake (Vo(2)) kinetics during endurance exercise. Objective. This study compared exercise-onset and -offset Vo(2) kinetics in mildly affected persons with MS with heal...

  4. 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.

  5. Li+ intercalation in isostructural Li2VO3 and Li2VO2 with O2- and mixed O2-/F- anions

    OpenAIRE

    Chen, R.; Ren, S.; Yavuz, M. (Murat); Guda, A.A.; Shapovalov, V.; Witter, R.; Fichtner, M.; Hahn, H.

    2015-01-01

    Mixed-anion materials for Li-ion batteries have been attracting attention in view of their tunable electrochemical properties. Herein, we compare two isostructural (Fm3m) model intercalation materials Li2VO3 and Li2VO2F with O2- and mixed O2-/F- anions, respectively. Synchrotron X-ray diffraction and pair distribution function data confirm large structural similarity over long-range and at the atomic scale for these materials. However, they show distinct electrochemical properties and kinetic...

  6. Modified Secret Sharing over a Single Path in VoIP with Reliable Data Delivery

    Directory of Open Access Journals (Sweden)

    K.Maheswari

    2012-01-01

    Full Text Available Abstract Voice over Internet Protocol (VoIP is a new fancy and up growing technology. A major change in telecommunication industry is VoIP. The transmission of Real time voice data is not as easy as ordinary text data. The real time voice transmission faces lot of difficulties. It suffers from packet loss, delay, quality and security. These factors will affects and degrade the performance and quality of a VoIP. This paper addresses the security and packet delivery ratio of a VoIP using modified secret sharing algorithm over a single path with reduced packet loss. The simulation results show that higher security and reduced packet loss is achieved in terms of end €“ to €“ end delay and packet delivery ratio. The user gets bad quality of VoIP at the receiver side. This makes the deployment of real time application a challenging task. To overcome these challenges in VoIP, several solutions have been reported already. The proper selection of active path in the routing protocol has a great impact in terms of packet delivery ratio and route discovery process. To provide end to end security between the source destination pair, the single path routing scheme is introduced.

  7. 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.

  8. Synthesis and characterization of VO2-based thermochromic thin films for energy-efficient windows

    Science.gov (United States)

    Batista, Carlos; Ribeiro, Ricardo M.; Teixeira, Vasco

    2011-12-01

    Thermochromic VO2 thin films have successfully been grown on SiO2-coated float glass by reactive DC and pulsed-DC magnetron sputtering. The influence of substitutional doping of V by higher valence cations, such as W, Mo, and Nb, and respective contents on the crystal structure of VO2 is evaluated. Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed. In summary, all the dopant elements--regardless of the concentration, within the studied range-- formed a solid solution with VO2, which was the only compound observed by X-ray diffractometry. Nb showed a clear detrimental effect on the crystal structure of VO2. The undoped films presented a marked thermochromic behavior, specially the one prepared by pulsed-DC sputtering. The dopants effectively decreased the transition of VO2 to the proximity of room temperature. However, the IR modulation efficiency is markedly affected as a consequence of the increased metallic character of the semiconducting phase. Tungsten proved to be the most effective element on the reduction of the semiconducting-metal transition temperature, while Mo and Nb showed similar results with the latter being detrimental to the thermochromism.

  9. Synthesis and characterization of VO2-based thermochromic thin films for energy-efficient windows

    Directory of Open Access Journals (Sweden)

    Batista Carlos

    2011-01-01

    Full Text Available Abstract Thermochromic VO2 thin films have successfully been grown on SiO2-coated float glass by reactive DC and pulsed-DC magnetron sputtering. The influence of substitutional doping of V by higher valence cations, such as W, Mo, and Nb, and respective contents on the crystal structure of VO2 is evaluated. Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed. In summary, all the dopant elements--regardless of the concentration, within the studied range-- formed a solid solution with VO2, which was the only compound observed by X-ray diffractometry. Nb showed a clear detrimental effect on the crystal structure of VO2. The undoped films presented a marked thermochromic behavior, specially the one prepared by pulsed-DC sputtering. The dopants effectively decreased the transition of VO2 to the proximity of room temperature. However, the IR modulation efficiency is markedly affected as a consequence of the increased metallic character of the semiconducting phase. Tungsten proved to be the most effective element on the reduction of the semiconducting-metal transition temperature, while Mo and Nb showed similar results with the latter being detrimental to the thermochromism.

  10. 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.

  11. Properties of VO2 Films Sputter-Deposited from V2O5 Target

    Science.gov (United States)

    Tsai, Kuang-Yue; Chin, Tsung-Shune; Shieh, Han-Ping D.

    2003-07-01

    Rutile VO2 is a thermochromic material that exhibits a reversible metal-insulator phase transition upon thermal cycling. A new deposition process of rutile VO2 from a V2O5 target was developed using reactive oxygen instead of hydrogen. Adjusting the substrate temperature and the oxygen flow ratio changes the compositions and phases of the as-deposited films into rutile VO2 under optimum deposition conditions on the Si and thick glass substrates. Crystalline phases analyzed by X-ray diffraction shows the relationship among V4O9, V6O13, and VO2 films prepared under different deposition conditions. Analysis by AFM shows that VO2 films grown at higher substrate temperatures have larger grain size. The optical switching property of VO2 was measured at a wavelength of 1.5 μm and transition temperature around 45°C was also measured. Inhomogeneity and the strained structure of the film are suggested to be the reasons of transition temperature lower than typical reported value because the impurity in the target is too low to be detected quantatively by ICP.

  12. The preparation of a plasmonically resonant VO{sub 2} thermochromic pigment

    Energy Technology Data Exchange (ETDEWEB)

    Bai Huaping; Cortie, Michael B; Maaroof, Abbas I; Dowd, Annette; Kealley, Catherine; Smith, Geoffrey B [Institute for Nanoscale Technology, University of Technology Sydney, PO Box 123, Broadway, NSW 2007 (Australia)], E-mail: michael.cortie@uts.edu.au

    2009-02-25

    Vanadium dioxide (VO{sub 2}) undergoes a reversible metal-insulator transition, normally at {approx}68 {sup 0}C. While the properties of continuous semi-transparent coatings of VO{sub 2} are well known, there is far less information available concerning the potential use of discrete VO{sub 2} nanoparticles as a thermochromic pigment in opaque coatings. Individual VO{sub 2} nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO{sub 2} nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO{sub 2} powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties.

  13. 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.

  14. 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.

  15. 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...

  16. 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.

  17. 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.

  18. Transport phenomena in SrVO3 thin films

    Science.gov (United States)

    Gu, Man; Wolf, Stuart; Lu, Jiwei; University of Virginia Team

    2013-03-01

    Bulk SrVO3 (SVO) with a 3d1 electronic configuration has been found to exhibit metallic and Pauli paramagnetic behavior. We have obtained epitaxial SVO films grown on various substrates (STO, SLAO, LSAT and LAO) using a pulsed electron-beam deposition (PED) technique. The film transport properties were found to be strongly dependent on the substrate. A 40 nm SVO film deposited on an STO substrate exhibited metallic behavior with the electrical resistivity following a T2 law that corresponds to a Fermi liquid system, the resistance ratio R(300K)/R(2K) was ~ 1.66. Hall measurements showed that the mobility increased slightly as the temperature was decreased. A small positive out-of-plane magnetoresistance was observed, it was only 0.045% at 5 K and 7 Tesla. SVO films with the same thickness grown on SLAO, LSAT and LAO showed semiconducting behavior, the different transport properties in the SVO films could be attributed to the compressive film strain or the different film-substrate interfaces.

  19. Theory on photoemission and inverse photoemission spectra in VO2

    International Nuclear Information System (INIS)

    The photoemission (PES) and inverse photoemission (IPES) spectra in VO2 at temperatures above and below the metal-insulator transition (MIT) are discussed with a two-band Hubbard model. An abrupt change in the valence top character of the theoretical PES spectra at the MIT caused by a switching in the t2g orbital occupation in the ground state is found. In the insulating phase, the structure of the valence top is well described within a single-band Hubbard model, where only the d|| band participates. Since the ratio t/U∼0.2 is small, the structure of the spectrum extends to ∼1.5eV below the Fermi level. On the other hand, in the metallic phase, both the dparallel and π* bands are involved and the spectral weight is concentrated in the vicinity of the Fermi level within a range ∼0.5eV. Such a large spectral weight transfer is consistent with experiments. For the IPES spectra, a structure corresponding to the upper Hubbard band of the single-band Hubbard model is appeared at ∼1.5eV above the Fermi level in the insulating phase. However the structure is absent in the metallic phase

  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. 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...

  2. 利用VoIP技术建立石化企业内部电话系统%Petrochemical Corporations Use VoIP Technology to Establish Private Branch Exchange

    Institute of Scientific and Technical Information of China (English)

    许慕阳

    2010-01-01

    VoIP技术是一种利用网络传播语音、视频图像的技术,目前广泛应用于全球语音通话系统和企业电话交换系统.文章介绍了VoIP技术原理,以及VoIP核心技术IP-PBX的功能.提出了企业建立VoIP电话系统的两种备选方案,一是使用商业产品建立VoIP系统,二是使用开源技术建立VoIP系统,并阐述了企业应用这两种方案的具体技术手段.

  3. 浅析VoIP技术在甚高频地空通信系统中的应用%Analysis the Application of VoIP Technology in the VHF Communication System

    Institute of Scientific and Technical Information of China (English)

    封燕; 卢宇

    2014-01-01

    VoIP技术是利用IP网络来传递语音信号的一种技术,近年来得到了广泛的应用和发展。该文首先分析VoIP技术的出现对甚高频地空通信系统的影响,进而分析VoIP技术在甚高频地空通信系统的应用。%VoIP is a technology of using IP network to transmit voice signal .It has been developed and used widely in recent years.This paper firstly analyzes the VoIP impacts on VHF communication system,and analyzes the application of VoIP in the VHF communication system.

  4. 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.   

  5. Biomasa de la vegetación herbacea y leñosa pequeña y necromasa en el área de influencia de la central hidroeléctrica Porce II

    OpenAIRE

    Herrera Arango, María Alejandra

    2002-01-01

    Este trabajo se realizó en los bosques primarios y secundarios del área de influencia de la Central Hidroeléctrica Porce II, en el departamento de Antioquia, Colombia. La región se encuentra entre 925 y 1500 msnm, con una precipitación promedia anual de 3050 mm/año. Se cuantificó el aporte de la vegetación herbácea y leñosa pequeña (VH&LP) como parte de la biomasa aérea, así como el aporte de los detritos vegetales tanto en el suelo como el vuelo (hojarasca fina, detritos de madera gruesa y á...

  6. 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.

  7. 无机盐离子对多孔 VO 2薄膜微观形貌及热致相变性能的影响∗%The effects of different inorganic ions on the morphology and thermochromic properties of porous VO2 films

    Institute of Scientific and Technical Information of China (English)

    陈敏; 徐元杰; 黄婉霞; 王姗姗

    2014-01-01

    Porous vanadium dioxide films had been fabricated by adding the same main group and different radius inorganic ions Li+,Na+,K+,the same cycle and different valence inorganic ions Na+,Mg2+,Al3+on muscovite (001)substratum with the addition of surfactant cetyltrimethyl ammonium bromide (CTAB)by sol-gel meth-od.SEM and FT-IR were used to analyze the morphology and thermochromic properties of the films.The results reveal that different valence and size inorganic ions have great effects on grain size,morphology and thermo-chromic properties of porous VO2 films.%以云母(001)为衬底,采用无机溶胶-凝胶法,通过添加表面活性剂十二烷三甲基溴化铵(CTAB),以及加入同一元素族、不同粒径的无机盐离子 Li+、Na+、K+和同一周期、不同价态的 Na+、Mg2+、Al3+制备多孔 VO2薄膜。采用SEM、FT-IR等手段分析薄膜的微观形貌特征和热致相变性能。结果表明,不同化合价、不同粒径的无机盐离子对多孔VO2薄膜的颗粒尺寸分布、微观形貌以及热致相变性能产生影响。

  8. The role of cadence on the VO2 slow component in cycling and running in triathletes.

    Science.gov (United States)

    Billat, V L; Mille-Hamard, L; Petit, B; Koralsztein, J P

    1999-10-01

    The purpose of this study was to compare the effect of two different types of cyclic severe exercise (running and cycling) on the VO2 slow component. Moreover we examined the influence of cadence of exercise (freely chosen [FF] vs. low frequency [LF]) on the hypothesis that: 1) a stride frequency lower than optimal and 2) a pedalling frequency lower than FF one could induce a larger and/or lower VO2 slow component. Eight triathletes ran and cycled to exhaustion at a work-rate corresponding to the lactate threshold + 50% of the difference between the work-rate associated with VO2max and the lactate threshold (delta 50) at a freely chosen (FF) and low frequency (LF: - 10 % of FF). The time to exhaustion was not significantly different for both types of exercises and both cadences (13 min 39 s, 15 min 43 s, 13 min 32 s, 15 min 05 s for running at FF and LF and cycling at FF and LF, respectively). The amplitude of the VO2 slow component (i.e. difference between VO2 at the last and the 3rd min of the exercise) was significantly smaller during running compared with cycling, but there was no effect of cadence. Consequently, there was no relationship between the magnitude of the VO2 slow component and the time to fatigue for a severe exercise (r = 0.20, p = 0.27). However, time to fatigue was inversely correlated with the blood lactate concentration for both modes of exercise and both cadences (r = - 0.42, p = 0.01). In summary, these data demonstrate that: 1) in subjects well trained for both cycling and running, the amplitude of the VO2 slow component at fatigue was larger in cycling and that it was not significantly influenced by cadence; 2) the VO2 slow component was not correlated with the time to fatigue. If the nature of the linkage between the VO2 slow component and the fatigue process remains unclear, the type of contraction regimen depending on exercise biomechanic characteristics seems to be determinant in the VO2 slow component phenomenon for a same level of

  9. 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.

  10. Li(+) intercalation in isostructural Li2VO3 and Li2VO2F with O(2-) and mixed O(2-)/F(-) anions.

    Science.gov (United States)

    Chen, Ruiyong; Ren, Shuhua; Yavuz, Murat; Guda, Alexander A; Shapovalov, Viktor; Witter, Raiker; Fichtner, Maximilian; Hahn, Horst

    2015-07-14

    Mixed-anion materials for Li-ion batteries have been attracting attention in view of their tunable electrochemical properties. Herein, we compare two isostructural (Fm3̅m) model intercalation materials Li2VO3 and Li2VO2F with O(2-) and mixed O(2-)/F(-) anions, respectively. Synchrotron X-ray diffraction and pair distribution function data confirm large structural similarity over long-range and at the atomic scale for these materials. However, they show distinct electrochemical properties and kinetic behaviour arising from the different anion environments and the consequent difference in cationic electrostatic repulsion. In comparison with Li2VO3 with an active V(4+/5+) redox reaction, the material Li2VO2F with oxofluoro anions and the partial activity of V(3+/5+) redox reaction favor higher theoretical capacity (460 mA h g(-1)vs. 230 mA h g(-1)), higher voltage (2.5 V vs. 2.2 V), lower polarization (0.1 V vs. 0.3 V) and faster Li(+) chemical diffusion (∼10(-9) cm(2) s(-1)vs. ∼10(-11) cm(2) s(-1)). This work not only provides insights into the understanding of anion chemistry, but also suggests the rational design of new mixed-anion battery materials. PMID:26073634

  11. Hydrothermal synthesis of Mo-doped VO2/TiO2 composite nanocrystals with enhanced thermochromic performance.

    Science.gov (United States)

    Li, Dengbing; Li, Ming; Pan, Jing; Luo, Yuanyuan; Wu, Hao; Zhang, Yunxia; Li, Guanghai

    2014-05-14

    This paper reports a one-step TiO2 seed-assistant hydrothermal synthesis of Mo-doped VO2(M)/TiO2 composite nanocrystals. It was found that excess Mo doping can promote formation of the VO2(M) phase, and rutile TiO2 seed is beneficial to morphology control, size reduction, and infrared modulation of Mo-doped VO2(M) nanocrystals. The Mo-doped VO2 nanocrystals epitaxially grow on TiO2 seeds and have a quasi-spherical shape with size down to 20 nm and a nearly 35% infrared modulation near room temperature. The findings of this work demonstrate important progress in the near-room-temperature thermochromic performance of VO2(M) nanomaterials, which will find potential application in constructing VO2(M) nanocrystal-based smart window coatings. PMID:24734771

  12. Hydrogen-doping induced reduction in the phase transition temperature of VO2: a first-principles study.

    Science.gov (United States)

    Cui, Yuanyuan; Shi, Siqi; Chen, Lanli; Luo, Hongjie; Gao, Yanfeng

    2015-08-28

    VO2 is a promising thermochromic material that can intelligently control the transmittance of sunlight in the near-infrared region in response to temperature change, although the high phase transition temperature (Tc) of 340 K restricts its wide application. Our first-principles calculations show that hydrogen is an efficient dopant which can stabilize the metallic VO2 phase at ambient temperature through reducing Tc by 38 K/at% H. The reduction in Tc is coupled with the changes in atomic and electronic structures, i.e., the V-V chains feature the dimerization characteristics in H-doped VO2(R) and the V-O bonds become less ionic due to the formation of a typical H-O covalent bond. In addition, hydrogen-doped VO2 is more sensitive to external strain as compared with pure VO2, implying that Tc can be further regulated through a combination of H-doping and strain. PMID:26214593

  13. 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.

  14. Growth of b-axis oriented VO2 thin films on glass substrates using ZnO buffer layer

    International Nuclear Information System (INIS)

    VO2 thin films are grown on glass substrates by pulsed laser deposition using vanadium metal as a target. In this study, a ZnO thin film was used as a buffer layer for the growth of VO2 thin films on glass substrates. X-ray diffraction studies showed that the VO2 thin film had b-axis preferential orientation on a c-axis oriented ZnO buffer layer. The thickness of the ZnO buffer layer and the oxygen pressure during VO2 deposition were optimized to grow highly b-axis oriented VO2 thin films. The metal-insulator transition properties of the VO2 film samples were investigated in terms of infrared reflectance and electrical resistance with varying temperatures.

  15. VoIP技术的新发展及其在电力通信中的应用%New Development of VoIP and Its Application in Power Communication

    Institute of Scientific and Technical Information of China (English)

    衷宇清; 宗凌

    2005-01-01

    介绍了VoIP技术的工作原理和系统构成,阐述了H.323协议,并介绍了VoIP最新技术的发展,具体分析了IP电话的工作过程,最后根据广州电力通信网的结构,深入分析了VoIP的应用范围,采用UCD设备进行VoIP试验,达到了预期效果.

  16. Facile synthesis and photocatalytic activity of monoclinic BiVO4 micro/nanostructures with controllable morphologies

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Highlights: ► BiVO4 micro/nanostructures have been synthesized by a facile solvothermal method. ► The shapes of BiVO4 micro/nanostructures can be controlled by tuning the synthetic parameters. ► BiVO4 nanorods with rectangular cross sections exhibit improved photocatalytic activities. -- Abstract: Monoclinic BiVO4 (m-BiVO4) micro/nanostructures, such as nanorods, nanofibers, bundle-like nanostructures, and porous submicrometer-sized rods, have been successfully synthesized by a facile solvothermal method in an ethylene glycol–water–sodium oleate system. The morphologies and sizes of m-BiVO4 micro/nanostructures can be controlled by adjusting the synthetic parameters, such as the concentrations of sodium oleate and reaction time. Among them, the synthesized m-BiVO4 nanorods have rectangular cross sections, and can grow along the [0 0 1] direction, and are enclosed by well-defined facets, such as (0 0 2), (2 4 0), and (2¯10), which are distinct from that with circular cross sections. A crystallization-cleavage-disassembly process has been proposed for the formation of m-BiVO4 nanorods with rectangular cross sections. The photocatalytic activity of m-BiVO4 nanostructures is affected greatly by the sizes and shapes of m-BiVO4 nanostructures. Photocatalytic measurements show that the m-BiVO4 nanorods with rectangular cross sections exhibit higher photocatalytic activities of Rhodamine B in comparison with m-BiVO4 nanofibers with circular cross-sections and porous submicrometer-sized rods.

  17. 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.

  18. 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

  19. 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.

  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. Effects of O2 pressure on the oxidation of VO(x)/Pt(111).

    Science.gov (United States)

    Tang, Zhenyan; Wang, Shaolin; Zhang, Lihua; Ding, Ding; Chen, Mingshu; Wan, Huilin

    2013-08-01

    Vanadium oxide (VO(x)) has been extensively used in many oxidation and selective oxidation reactions. In this study, VO(x) thin films were prepared in an ultra-high vacuum (UHV) chamber by evaporating V onto a Pt(111) surface followed by subsequent oxidation at 623 K in 1 × 10(-7) Torr O2, and further oxidized in the 'high-pressure' reaction cell with 1 Torr O2. The film quality and structure were investigated by high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), low energy ion scattering spectroscopy (LEIS), Auger electron spectroscopy (AES), and in situ infrared reflection absorption spectroscopy (IRAS). On the Pt(111) surface, VO(x) forms isolated O=VO(x) (x = 0-3) species, surface two-dimensional (2D) (2 × 2)-V2O3 domains, a bi-layer structure with a (3√3 × 6) arrangement, and a complicated tri-layer structure as the coverage increases from submonolayer to multilayer. Under the UHV conditions, the oxidation state of V is mainly +3 and the stability was found to be surface V2O3 > bi-layer V2O3 > tri-layer one. After exposing to 0.3-1 Torr O2, VO(x) can be oxidized to higher oxidation states, mainly V2O5, as evidenced by the shifts of the core-level binding energies and presence of V=O. These results indicate that thorough oxidation of VO(x) requires sufficiently high O2 pressure, and that vanadium-based catalysts may possess higher oxidation states under most reaction conditions in the presence of O2. PMID:23665594

  2. 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.

  3. UPRAVLJANJE RIZIKOM NA VOĆARSKIM I VINOGRADARSKO-VINARSKIM GOSPODARSTVIMA SLAVONIJE I BARANJE

    OpenAIRE

    Njavro, Mario; Jakobović, Snježana; Budimir, Verica

    2005-01-01

    Rad prikazuje rezultate anketnog ispitivanja o percepcijama rizika i upravljanju rizikom na voćarskim i vinogradarsko-vinarskim gospodarstvima Slavonije i Baranje. Najvažniji izvor rizika je briga za zdravlje članova gospodarstva, a sljede klimatski čimbenici i skupina tržišnih rizika. Po važnosti strategija za upravljanje rizikom, na prvom je mjestu primjena odgovarajuće tehnologije proizvodnje. Zamjetan je jaz između ocjene važnosti poljoprivrednog osiguranja i njegove primjene na gospodars...

  4. A thermochromic low-emittance coating : Calculations for nanocomposites of In2O3:Sn and VO2

    OpenAIRE

    Li, Shuyi; Niklasson, Gunnar A.; Granqvist, Claes-Göran

    2011-01-01

    Calculations based on the Bruggeman effective medium theory were applied to thin films comprising a heavily doped wide band gap semiconductor (specifically In(2)O(3):Sn (ITO)) and VO(2). Films with similar to 20 vol. % of VO(2) can combine a 10% thermochromic modulation of the solar energy throughput with a luminous transmittance of 50%-60% and low thermal emittance. The maximum thermochromic modulation is similar to 13% and occurs at similar to 35 vol. % VO(2). Coatings of ITO-VO(2) are of i...

  5. An Efficient Scheduling Scheme to Enhance the Capacity of VoIP Services in Evolved UTRA Uplink

    Directory of Open Access Journals (Sweden)

    Kim Yong-Seok

    2008-01-01

    Full Text Available An efficient scheduling scheme is proposed to increase the available capacity of VoIP services over evolved UTRA uplink. On top of the advantages of persistent scheduling, the proposed scheme adaptively share the resources of two VoIP users to get early-termination gain of dynamic scheduler. Through system-level simulations, the performance of the proposed algorithm is evaluated in terms of the capacity enhancement of VoIP services. Comparisons with the original persistent scheduling and the HSUPA scheduler reveal that the proposed scheme increases the capacity of VoIP services up to 20%.

  6. Repeated Sprint Performance in Male and Female College Athletes Matched for VO2max Relative to Fat Free Mass

    OpenAIRE

    MAGEEAN, AMANDA L.; ALEXANDER, RYAN P.; MIER, CONSTANCE M.

    2011-01-01

    The purpose of this study was to examine gender differences in repeated sprint exercise (RSE) performance among male and female athletes matched for VO2max relative to FFM (VO2max FFM). Thirty nine male and female college athletes performed a graded exercise test for VO2max and hydrostatic weighing to determine FFM. From the results, 11 pairs of males and females matched for VO2max FFM (mean ± SD; 58.3 ± 4.3 and 58.9 ± 4.6 ml·kg FFM−1·min−1; men and women, respectively) were identified. On a ...

  7. Use of a Nonexercise Estimate for Prestroke Peak Vo2 During the Acute Stroke Hospital Stay

    Science.gov (United States)

    Mattlage, Anna E.; Redlin, Sara A.; Rosterman, Lee R.; Harn, Nick; Sisante, Jason-Flor V.; Abraham, Michael G.; Billinger, Sandra A.

    2016-01-01

    Purpose For individuals with acute stroke, it is difficult to conduct an exercise test to assess peak oxygen consumption (peak Vo2). Therefore, the purpose of this study was to use a clinically feasible tool for assessing prestroke peak Vo2 using a nonexercise estimation equation to test whether estimated prestroke peak Vo2 was related to the functional outcome measures at discharge from the hospital in individuals after an acute stroke. We hypothesized that the estimated prestroke peak Vo2 would be significantly related to discharge Physical Performance Test (PPT), 6-minute walk test (6MWT), and lower extremity Fugl-Meyer (LEFM) assessment. Methods Estimated prestroke peak Vo2 was calculated using a previously validated prediction equation using the following variables: body mass index, age, sex, resting heart rate, and a self-reported measure of physical activity. Outcome measures were assessed 4 days after enrollment or immediately before discharge (whichever occurred first). Results Thirty-four participants (mean age = 56.0, SD = 12.6 years; 20 men) with acute stroke were enrolled within 48 hours of admission. For all individuals, mean estimated prestroke peak Vo2 was 27.3 (SD = 7.4) mL·kg−1·min−1 and had a weak, nonsignificant relationship with the PPT (r = 0.19; P = .28), 6MWT (r = 0.10; P = .56), and LEFM (r = 0.32; P = .06). However, when considering sex, women, but not men, had a significant relationship with LEFM (r = 0.73; P = .005) and moderate but nonsignificant relationship with PPT (r = 0.53; P = .06) and 6MWT (r = 0.47; P = .10). Conclusions Within 48 hours of stroke admission, we were able to administer a nonexercise equation to estimate prestroke peak Vo2. For the entire sample, functional measures conducted at discharge were not related to estimated prestroke peak Vo2. However, when considering sex, the relationship between prestroke Vo2 and the functional measures was strengthened.

  8. High quality, hybrid-MBE growth of SrVO3 thin films

    Science.gov (United States)

    Moyer, Jarrett; Eaton, Craig; Engel-Herbert, Roman

    2013-03-01

    Vanadium-based transition metal oxides are an intriguing class of materials to study due to the metal-to-insulator (MIT) transitions that arise in many of the binary oxides (i.e. VO2, V2O3, V2O5) . The perovskite SrVO3 is metallic in bulk; however, it is possible to induce an MIT by modulating the bandwidth through strain or dimensional confinement. A mandatory requirement for controlling the electronic phase transition properties in material systems with strong correlation is the growth of high quality, stoichiometric thin films. This is demonstrated here with the growth of SrVO3 on LSAT (001) substrates using a hybrid-MBE technique, where the Sr is evaporated from an effusion cell and the V is provided through the metal-organic precursor vanadium oxo-tri-isopropoxide (VTIP). The structural properties of films with varying VTIP:Sr ratios are characterized by RHEED, XRD, AFM and TEM. These measurements demonstrate that SrVO3 can be grown with excellent structural quality, atomically flat surfaces and rocking curves of the same width as the substrate, accomplishing a necessary first step in controlling the MIT in SrVO3. This research is primarily supported by ONR Grant N00014-11-1-0665

  9. 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

  10. 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.

  11. 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.

  12. VO2+ 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-B2O3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in zinc lead borate glasses were present in octahedral sites with tetragonal compression and belong to C4V symmetry. The spin-Hamiltonian parameters g and A are found to be independent of V2O5 content and temperature but changing with ZnO content. The decrease in Deltag( parallel)/Deltag( perpendicular) value with increase in ZnO content indicates that the symmetry around VO2+ ions is more octahedral. The decrease in intensity of EPR signal above 10 mol% of V2O5 is attributed to a fall in the ratio of the number of V4+ ions (N4) to the number of V5+ ions (N5). The number of spins (N) participating in resonance was calculated as a function of temperature for VO2+ 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/chi-T graph. The optical absorption spectra show single absorption band due to VO2+ ions in tetragonally distorted octahedral sites. PMID:16043053

  13. First finding of impact melt in the IIE Netschaëvo meteorite

    Science.gov (United States)

    Roosbroek, N.; Pittarello, L.; Greshake, A.; Debaille, V.; Claeys, P.

    2016-02-01

    About half of the IIE nonmagmatic iron meteorites contain silicate inclusions with a primitive to differentiated nature. The presence of preserved chondrules has been reported for two IIE meteorites so far, Netschaëvo and Mont Dieu, which represent the most primitive silicate material within this group. In this study, silicate inclusions from two samples of Netschaëvo were examined. Both silicate inclusions are characterized by a porphyritic texture dominated by clusters of coarse-grained olivine and pyroxene, set in a fine-grained groundmass that consists of new crystals of olivine and a glassy appearing matrix. This texture does not correspond to the description of the previously examined pieces of Netschaëvo, which consist of primitive chondrule-bearing angular clasts. Detailed petrographic observations and geochemical analyses suggest that the investigated samples of Netschaëvo consist of quenched impact melt. This implies that Netschaëvo is a breccia containing metamorphosed and impact-melt rock (IMR) clasts and that collisions played a major role in the formation of the IIE group.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Ag-BiVO4催化剂的制备及其用于光催化氧化噻吩%Prepatation of Ag-BiVO4 Catalyst and Its Application to Photocatalytic Oxidative Desulfurization

    Institute of Scientific and Technical Information of China (English)

    高晓明; 付峰; 张理平; 武玉飞; 王静; 王继武

    2012-01-01

    采用水热法合成了可见光催化剂Ag - BiVO4,并对其进行了XRD和UV - Vis DRS表征.以噻吩的正辛烷溶液为含硫模型化合物溶液,考察了Ag - BiVO4催化剂前体的pH、Ag - BiVO4催化剂用量和空气流量等工艺条件对脱硫率的影响,研究了Ag - BiVO4催化剂光催化氧化噻吩的性能.表征结果显示,Ag的掺杂没有改变BiVO4的晶相,在Ag - BiVO4催化剂前体的pH为7的条件下制备的Ag - BiVO4催化剂(Ag - BiVO4 (pH=7))结晶度较好,吸收边带明显红移,禁带宽度窄于纯BiVO4.实验结果表明,Ag-BiVO4 (pH=7)催化剂活性最高,在空气流量为300 mL/min、Ag -BiVO4(pH=7)催化剂加入量为1.0 mg/L、400W金卤灯照射180 min的条件下,脱硫率可达95%.%Ag-BiVO4 photocataiysts were prepared by hydrothermal method and were characterized by means of UV-Vis DRS and XRD. The desulfurization activity of Ag-BiVO4 catalysts for thiophene in octane as model sulfur compounds was researched by photocatalytic oxidation under visible light. The effects of the precursor pH, Ag-BiVO4 catalyst dosage and air flux on the desulfurization rate were investigated. The results indicated that the Ag doping did not change the crystal phase of BiVO4, and the crystallinity of Ag-BiVO4 prepared with BiVO4 precursor pH 7 (Ag-BiVO4(pH=7)) was the best. Under the optimal conditions of air flux 300 mL/min, Ag-BiVO4(pH=7) catalyst dosage 1.0 mg/L and illumination time 180 min with 400 W metal halide light, the desulfurization rate could reach 95%. The Ag-BiVO4 catalyst had a significant red-shift in the absorption band in the visible region, and the width of its forbidden band was narrower than that of BiVO4.

  20. 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.