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  1. System Ca3(VO4)2-Na3VO4-LaVO4

    Using the method of x-ray phase analysis, the phase equilibria in the system Ca3(VO4)2-Na3VO4-LaVO4 were studied. An extensive solid solution in calcium orthovanadate bounded by the compositions Ca3(VO4)2-Ca9La(VO4)7-Ca10Na(VO4)7-Ca8.5Na1.75La0.75(V)4)7 was found. The unit cell parameters of whitlockite vanadates increase with a rise in the sodium or lanthanum concentration. Ferroelectric phase transitions in Ca3-3xLa2x(VO4)2 vanadates were studied using thermal analysis, electrical conductivity measurements, and dielectric constant measurements

  2. Phases of variable composition in the Ca3(VO4)2-NdVO4 - Na3VO4 system

    Phase equilibriums in the Ca3(VO4)2 - NdVO4-Na3VO4 system are studied. Formation of variable composition phases on the base of calcium orthovanadate is established. The field of variable composition phase is placed inside of Ca3(VO4)2 - Ca9Nd□(VO4)7 - Ca10Na(VO4)7 - Ca8NdNa2(VO4)7 (Z = 6) quadrangle. Boundary compositions are determined by structure of low temperature modification of Ca3(VO4)2 (Z = 21, sp. gr. R3c). The degree of Ca(4) positions occupancy has influence on phase transition temperature, ionic conductivity and parameters of IR- and CS-spectra. Considerable growth of the conductivity higher than 650 K on the calcium ions is explained by order-disorder transformation associated with disproportional of structural vacancies (□) on different cation positions

  3. Interaction in the FeVO4-NaOH-NaCl-H2O system

    The solubility in the FeVO4-NaOH-NaCl-H2O system is studied using the saturation method at 22+-0.5 deg C and constant ionic force μ=1.0. The existence of the basic mixed sodium and iron (3) ortho- vanadates of the composition: Na4Fe9(OH)4(VO4)9xnH2O, NaFeOHVO4xnH2O, Na2Fe(OH)2VO4xnH2O is established. Conditions of their preparation and the results of IR spectroscopic study of the salts are presented

  4. Solubility in the NH4Cl-NaVO3-NH4VO3-NaCl-H2O system

    Solubility of salts in reciprocal system NH4Cl-NaVO3-NH4VO3-NaCl-H2O at 20 deg C was studied by the method of isothermal saturation using the chemical and X-ray phase analyses, the system solubility diagram being plotted. The diagram contains separate fields of salts crystallization, limited by five branches, and two ternary points. The ratio of the salts crystallization surface areas is approximately equal to 90000:10000:3:1 (NH4VO3:NaVO3:NaCl:NH4Cl), i.e. above 90% of crystallization field is occupied by ammonium vanadate, featuring the lowest solubility

  5. Sodium calcium orthovanadate, NaCa4(VO4)3.

    Ben Yahia, Hamdi; Gaudin, Etienne; Darriet, Jacques

    2005-07-01

    Single crystals of sodium tetracalcium trivanadium dodecaoxide were prepared by melting a powder sample of NaCa4(VO4)3 at 1673 K, followed by slow cooling to room temperature. The compound crystallizes in the Pnma space group and is isostructural with the mineral silicocarnotite, Ca5(PO4)2SiO4. The structure is composed of isolated VO4 tetrahedra linked by sodium and calcium cations disordered over eight- and seven-coordinated sites. PMID:15997052

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

    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.

  7. System Na3VO4-Na4V2O7-Na2WO4

    State diagrams of sodium-orthovanadate-sodium tungstate, sodium pyrovanadatesodium tungstate systems and crystallization surface of sodiumorthovanadate-sodium pyrovanadate-sodium tungstate system were studied. Na5VWO8 compound forms in sodium orthovanadate-sodium tungstate system in solid state. Congruently melting Na6V2WO11 compound forms in sodium pyrovanadate-sodium tungstate system. Liquidus diagram of sodium orthovanadate-sodium pyrovanadate-sodium tungstate system was constructed. Compositions and melting points of ternary eutectic points were determined. 4 refs.; 3 figs.; 3 tabs

  8. High-temperature Raman spectroscopic study of vanadoborate Na3VO2B6O11

    Ji, Zhang; De-Ming, Zhang; Qing-Li, Zhang; Shao-Tang, Yin

    2016-03-01

    Raman spectra of a vanadoborate (Na3VO2B6O11) crystal from room temperature up to the melting point have been recorded. The main internal vibrational modes of the crystal have been assigned. It was found that all the Raman bands exhibit decreases in frequency and the widths of the Raman bands increase with the increase of temperature. However, no phase transition was observed under 525 °C. The micro-structure of its melt was studied by quantum chemistry ab initio calculation. The continuous three-dimensional network of the crystal collapsed and transformed into VO4 and VBO6 clusters during the melting process with an isomerization reaction from four-coordinated boron to a three-coordinated species. Project supported by the National Natural Science Foundation of China (Grant Nos. 51302268 and 51102239) and the Natural Science Foundation of Anhui Province, China (Grant No. KJ2015A339).

  9. Biomasa en Chile

    Nilsson Cifuentes, Gabriel; Rodríguez Monroy, Carlos

    2012-01-01

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

  10. Ponašanje potrošača suhog voća na tržištu grada Zagreba

    Cerjak, Marija; Tomić, Marina

    2014-01-01

    Cilj ovog istraživanja je bio utvrditi najvažnija obilježja kupnje i potrošnje suhog voća na tržištu grada Zagreba. U anketnom ispitivanju je sudjelovalo 120 ispitanika. Rezultati istraživanja su pokazali da se suho voće relativno rijetko koristi u prehrani. U potrošnji suhog voća dominiraju grožđice i suhe šljive. Najčešći motivi za konzumaciju suhog voća su pozitivan utjecaj na probavu kao i dobar okus suhog voća. S druge strane, cijena kao najvažnije obilježje u kupnji suhog voća predstavl...

  11. Hot corrosion behaviour of Fe-Al based intermetallic in molten NaVO3 salt

    The hot corrosion of sprayed Fe-40 (at.%)Al intermetallic alloy with additions of boron and alumina whiskers in molten NaVO3 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 Al2O3 oxide scale, which made the diffusion of both reducing and oxidizing species through the scale to the alloy or scale surfaces more difficult. Equivalent electric model used to simulate the EIS data showed that a finite length Warburg diffusion could properly characterize the diffusion process, which confirmed the formation of a compact corrosion product scales containing rich aluminium oxide. Thus, the corrosion process was under diffusion control of aggressive ions through the formed scale. The electrochemical study was complemented by scanning electronic microscopy characterization and micro chemical analysis.

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

    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.

  13. A novel orange-red emitting NaCaVO4:Sm3+ phosphor for solid state lighting

    Biswas, Pankaj; Kumar, Vinay; Ntwaeaborwa, O. M.; Swart, H. C.

    2016-05-01

    The samarium doped NaCaVO4 phosphor was synthesized by the combustion method. The X-ray powder diffraction (XRD) analysis confirmed that the phosphor powder crystallized as orthorhombic structure belonging to space group Cmcm. From Williamson-Hall analysis the grain size and microstrain in the powder was estimated. The Fourier- transform infrared (FT-IR) studies further validated the formation of vanadate phase of the phosphor. Photoluminescence (PL) study revealed that the phosphor could be efficiently excited by UV-VIS from 200 nm to 500 nm. The 565 nm, 602 nm, 648 nm and 713 nm emissions were ascribed to 4G5/2 to 6HJ (J = 5/2, 7/2, 9/2 and 11/2) transitions of the Sm3+ ion. The present material may be explored as a novel phosphor to be excited by UV light emitting diodes (LEDs) chips for solid-state lighting and display applications.

  14. Properties of La(Y)(NO3)3-Na3VO4 solutions and their botton phase composition

    Properties of a series of solutions La(Y)(NO3)3-Na3VO4 with a constant concentration of lanthanum (yttrium) nitrate and variable concentration of sodium vanadate, chemical and phase compositions of the bottom phases, formed both in eqUilibrium and nonequilibrium conditions at pHsub(Nasub(3)VOsub(4))=12.8(1) and 9.8(2), have been studied using the methods of PMR, DTA, IR spectroscopy, X-ray diffraction, crystallooptical and chemical analyses. It has been established that in series 1 normal lanthanum (yttrium) orthovanadate is formed. In series 2 in a nonequilibrium mixture of solutions dipolyvanadate of La(Y) together with acid salt of orthovanadic acid are formed, and in an equilibrium one-dipolyvanadate and normal salt of orthovanadic acid. The change in the bottom phase composition with time takes place at the expense of the acid salt dissolution and hydrolysis of cations with the subsequent deposition of normal salt of orthovanadic acid

  15. 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

    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

  16. Piloto de gasificador downdraft operado con biomasa

    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...

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

    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

  18. 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

    Fabrizio Caputo; Camila Coelho Greco; Benedito Sérgio Denadai

    2005-01-01

    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 ...

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

    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...

  20. Technologie VoIP

    Stieranka, Michal

    2007-01-01

    Práce nabízí principy moderních telekomunikačních technologií, zejména se zaměřuje na technologii VoIP (Voice over IP), neboli na Internetovou telefonii. První dvě části se soustředí na popis klasických telekomunikačních a datových technologií. Čtenář tak získá či si prohloubí znalosti principů klasické telefonie, seznámí se zde například s funkcí telefonních ústředen a telefonních linek, s různými technologiemi přenosu hlasu po pevných linkách apod. Dále čtenář získá nezbytný základ principů...

  1. Ciclos integrales de biomasa y desarrollo local. Experiencias aplicadas

    Rodrigo Alfonso, Carles; Delgado Franco, Xavi

    2015-01-01

    Históricamente, la gestión de la biomasa ha constituido una fuente básica de energía y ha contribuido a generar empleo y actividad económica. La difusión los combustibles fósiles y la ampliación de la red eléctrica restringieron el uso de la biomasa (fundamentalmente leña). En otros contextos territoriales este uso se mantuvo y se vio acompañado de importantes innovaciones tecnológicas.Las problemáticas asociadas al consumo de combustibles fósiles han propiciado en la última década un auge de...

  2. 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

    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

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

    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.

  4. Aprovechamiento energético de la biomasa

    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...

  5. Proyecto de una central eléctrica de biomasa

    Valentín Botija, Sergio

    2011-01-01

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

  6. Enriquecimiento de biomasa de levadura con micronutrientes esenciales

    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.

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

    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.

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

    Andro Pavuna; Dragutin Ivanec

    2012-01-01

    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 ko...

  9. Importancia energética y ambiental de la biomasa en colombia

    2011-01-01

    Entiéndase por energía de la biomasa aquélla que se origina al procesar parcial o totalmente cualquier sustancia o materia originada a través del proceso de fotosíntesis de los vegetales. Luego comprende especies y microespecies que cumplen para el hombre y el ecosistema una función especial ligada a factores climáticos, geomorfológicos y socioeconómicos. Antes de la aparición de los combustibles fósiles (otra forma concentrada de biomasa) y de la electricidad, la biomasa constituía la princi...

  10. Measurement and modeling for vanadium extraction from the (NaVO3 + H2SO4 + H2O) system by primary amine N1923

    Highlights: • LLE data for vanadium extraction by primary amine N1923 were obtained. • Three extraction reactions were determined with the slope method. • Thermodynamic equilibrium constants and new Pitzer parameters were regressed. • The prediction performance of this new model was discussed and verified. - Abstract: In this work, the solvent extraction of vanadium by using the primary amine N1923 as extractant was studied. Within different vanadium concentration ranges, the extraction reactions were determined using the slope method at T = 298.15 K based on the vanadium phase diagram. The slopes (the stoichiometric ratio) were determined as 5/3, 1 and 11/3 for (RNH2)5/3H3VO4,(RNH2)H3V3O9 and (RNH2)11/3H6V10O28, respectively. The thermodynamic model was established through regression of the experimental results with the Pitzer equation for both aqueous and organic phases by the General Algebraic Modelling System (GAMS). Three different sets of parameters and chemical equilibrium constants K were determined, which corresponded to the three extraction reactions. The orders of the lnK values are V10>V3>V1 (organic V species), and the distribution coefficients (DV) are DV1>DV3>DV10. The new model was applied to predict the regularities of extraction yield along with different initial conditions, and the results agree well with the experimental values

  11. Glavni karakteristiki na igraornite podracja

    Janevski, Vladimir

    2010-01-01

    koga stanuva zbor za igraornite podracja vo taa smisla se misli i na etnografskite karakteristiki vo Makedonija. Vo Makedonija postojat pet igraorni podracja i toa: Zapadnoto igraorno podracje, Jugozapadnoto igraorno podracje, juznoto igraorno podracje, Istocnoto igraorno podracje i severnoto igraorno podracje.

  12. Pishanite i vizuelnite izvori za tradicionalnite igra za krajot na XlX i pochetokot na XX vek

    Janevski, Vladimir

    2011-01-01

    Najranite podatoci vo literaturata koi se odnesuvaat direktno na tradicionalnoto igranje, formata, oblikot, stilot i repertoarot, poteknuvaat od krajot na XlX i pochetokot XX vek. Naporedno so literaturnite izvori se pojavuvaat i prvite vizuelni izvori vo Makedonija

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

    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.

  14. VoIP

    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...

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

    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...

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

    Fabiana Andrade Machado

    2013-03-01

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

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

    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.

  18. On vanadium(5) alcoholates. Behavior of VO2Cl to organic solvents

    By means of exchange reaction between VOCl3 and NaOR VO(OR)3 (R = Et, i - Pr) is prepared. It is shown that the interaction is complicated by the formation of alkoxychlorides, which are successfully destructed by the introduction of NaOR excess. For the synthesis of VO(OMe)3 the reaction of VO(OEt)3 reesterification by methyl alcohol is used. VO(OR)3 prepared is characterized by the data of IR spectroscopy, mass-spectrometry, X-ray phase analysis. Existence of dimeric molecules in gaseous phase is ascertained. The study of VO2Cl exchange reaction has shown that alcoholates of the series VO2(OR) can not be synthesized by the method, since in case of VO2Cl contact with alcohol alkoxyl is substituted for one oxogroup with the formation of VO(OR)2Cl. Solvolysis processes take place also in case of VO2Cl interaction with other oxygen-containing organic solvents

  19. Biomasa de Cornops aquaticum (Orthoptera: Acrididae) en humedales del nordeste de Argentina

    Luciana Irene Gallardo; María Celeste Franceschini; Alicia Susana Guadalupe Poi; María Laura De Wysiecki

    2015-01-01

    La estimación de la biomasa en las poblaciones de insectos, es un factor clave para cuantificar los recursos disponibles y los flujos de energía en las redes tróficas de los ecosistemas. Cornops aquaticum es un herbívoro común en las plantas de Eichhornia en los humedales del nordeste de Argentina. Nuestro objetivo fue analizar la variación de su biomasa en relación a las distintas categorías de edades de la población de este acridio, en dos plantas huésped: Eichhornia azurea y Eichhornia cra...

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

    Amengual Romaní, Carmen; Triguero Gil, Álvaro

    2013-01-01

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

  1. Calefaccion centralizada por biomasa, Cuéllar

    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

  2. VO Tools variety is the spice of VO life

    Osuna, P.

    2009-07-01

    The VO realm allows building of different clients to support the already vast amount of available data, for discovery, analysis, exploitation, mining, etc. The presence of an increasing amount of clients giving service to the VO community has been seen by some to be an added problem to the promotion of the VO. However, in real daily world IT activities, we find fair competing applications here and there, in an ever improving synergy that allows growing and perfecting. In this paper, we make a parallelism of some usual daily IT activities with VO ones, and we emphasize how different applications implement the same standards, both in our daily computer based activities and in the VO, and how this benefits evolution in the field.

  3. Právo na internet

    Lexová, Alžběta

    2013-01-01

    The Internet is one of the phenomenons of our time. As of speed and reach it surpasses all media on the world and unlike every other medium it actively engages all people to the process of creating the news. Basic attributes of the Internet make it a power standing above states -- it crosses national borders and doesn't have any direct owner -- and at the same time these attributes make it a power that is practically almost unregulatable. The Internet is regulated on a national level, but the...

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

    Martha Angélica Gutiérrez-Aguirre; María Gabriela de la Fuente-Betancourt; Adrián Cervantes-Martínez

    2000-01-01

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

  5. Estimación de la biomasa arbórea de "Eucalyptus globulus" y "Pinus pinaster" en Galicia

    Álvarez González, Juan Gabriel; Balboa Murias, M.; Merino, Agustín; Rodríguez Soalleiro, Roque

    2012-01-01

    En este trabajo se ha caracterizado la acumulación de biomasa arbórea en masas adultas de Eucalyptus globulus y Pinus pinaster en Galicia. Diferentes intereses industriales, energéticos y ambientales han motivado que en los últimos años el análisis de las distintas posibilidades de aprovechamiento de la biomasa forestal esté adquiriendo un creciente protagonismo, por lo que la cuantificación de la biomasa arbórea de estos sistemas forestales constituye un primer paso f...

  6. Gevaar VoIP voor telecomsector overdreven

    Deventer, M.O. van; Wegberg,M.,van

    2004-01-01

    Het is een hype Voice-over-IP (VoIP) voor te stellen als een ontwrichtende technologie die de telecomindustrie ingrijpend zal veranderen. Maar hoe ontwrichtend is VoIP eigenlijk? Oskar van Deventer en Marc van Wegberg analyseren drie vormen van VoIP en laten zien dat alleen ‘VoIP-chat’ potentieel een bedreiging is voor telefoniebedrijven.

  7. Accessing the VO with Python

    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.

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

    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

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

    Matías Lopez

    2014-01-01

    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

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

    Anirebis Martínez Romero; Angel Leyva Galán

    2014-01-01

    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 nec...

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

    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 ...

  12. VoIP security - attacks and solutions

    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...

  13. Modelos matemáticos y experimentales sobre el secado de biomasa

    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.

  14. VoIP Forensic Analyzer

    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.

  15. 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

    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

  16. VoIP over WLAN

    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...

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

    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.

  18. Speaker Recognition in the VoIP Environment

    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...

  19. 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

    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...

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

    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...

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

    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

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

    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 ...

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

    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...

  4. El ictioplancton y la biomasa del zooplancton en aguas del sur de Galicia, en abril de 1987.

    Rodríguez, J. M.; Pérez-de-Rubín-y-Feigl, J. (Juan)

    1991-01-01

    En este trabajo se describen la cmposición específica del ictioplancton larvario, los modelos de distribución de la biomasa zooplanctónica, del ictioplancton en general, del caso particular de los huevos y larvas de Maurolicus muelleri y las relaciones entre las abundancias del ictioplancton y de la biomasa zooplanctónica, en aguas del sur de Galicia, en abril de 1987. Finalmente, de la sardina (Sardina pilchardus) realizamos un estudio comparado del tamaño de sus huevos. La comunidad ictiopl...

  5. Sistemas de aprovechamiento de biomasa en Castilla y León : las experiencias en curso

    Tolosana Esteban, Eduardo; Ambrosio Torrijos, Y.; Laina Relaño, Rubén

    2008-01-01

    Se han realizado siete experiencias de aprovechamientos de biomasa en montes de Castilla y León y Andalucía financiadas por la Fundación Centro de Servicios y Promoción Forestal y de su Industria de Castilla y León (CESEFOR): tres en cortas selectivas de Quercus pyrenaica Willd. y Pinus sylvestris L. con saca de árbol completo con astillado o triturado fijo; dos en cortas a hecho de chopo y otra en pino silvestre con saca de restos y astillado o triturado fijo en ca...

  6. La biomasa en la producción de electricidad en España

    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.

  7. Evaluation of Voice over MPLS (VoMPLS) compared to Voice over IP (VoIP)

    Fjellskål, Edward Bjarte; Solberg, Stig

    2002-01-01

    This thesis is an evaluation of VoMPLS as it is presented in the VoMPLS Implementation Agreement from the MPLS Forum. The thesis evaluates VoMPLS and comparisons are made to VoIP. It is a theoretical study and no testing has been carried out. The object is to highlight theoretical aspects of VoMPLS, discuss and present a conclusion. This thesis also highlights the evolution from ATM to MPLS in UMTS networks, and looks into how VoMPLS can be used in UMTS. The necessary backgr...

  8. K vlivu velkomoravského práva na raně středověké české právo

    Havlíková, Lubomíra

    Nitra : Filozofická fakulta Univerzity Konštantína Filozofa - Ústav pre výskum kultúrneho dedičstva Konštantína a Metoda, 2008 - (Michalov, J.; Hetényi, M.; Ivanič, P.; Taneski, Z.), s. 22-32 ISBN 978-80-8094-455-1 Institutional research plan: CEZ:AV0Z90920516 Keywords : Great Moravian law * Czech law * influences Subject RIV: AB - History

  9. Performance of VoIP on HSDPA

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

    2005-01-01

    This paper provides packet scheduler design and performance simulations for running VoIP services over high-speed downlink packet access (HSDPA) in WCDMA. The main challenge of supporting VoIP service on HSDPA is the tight delay requirement combined with the small VoIP packet size. A packet...... 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 of...... proportional fair scheduling. For proportional fair scheduling with code-multiplexing of 4-users, the downlink VoIP cell capacity on HSDPA is found to be in the range 72-104 users depending on whether the delay budget for the Node-B scheduling and user reception equals 80 ms or 150 ms, respectively....

  10. VoIP Technology: Security Issues Analysis

    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...

  11. Investigation of VoIP and implementation

    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 ...

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

    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

  13. VoIP网络浅析

    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.

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

    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...

  15. Security in VoIP

    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...

  16. 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}.

    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

  17. Securing VoIP keeping your VoIP network safe

    (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

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

    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.

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

    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.

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

    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.

  1. VoIP to the Rescue

    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. Tunable VO2/Au hyperbolic metamaterial

    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.

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

    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...

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

    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...

  5. Security in VoIP

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

    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

  7. VoIP in Jabber Client

    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.

  8. Evaluación de la biomasa como recurso energético renovable en Cataluña

    Martínez Lozano, Sergio

    2009-01-01

    El objetivo principal es la evaluación de la biomasa como recurso energético renovable en Cataluña. Su alcance requiere el estudio de diversas temáticas, desarrolladas en los doce capítulos que componen el documento.El Capítulo 1 describe los objetivos de la tesis. El Capítulo 2 describe los motivos que justifican la valorización energética del recurso biomasa. El Capítulo 3 presenta la metodología general utilizada. El Capítulo 4 realiza un análisis multicriterio del aprovechamiento energéti...

  9. Condicionantes económicos del aprovechamiento de biomasa forestal con fines energéticos. Una revisión de las estimaciones para el norte de España

    2013-01-01

    Este artículo presenta una revisión de los estudios y ensayos disponibles sobre los costes de producción de biomasa forestal en el norte de España, particularmente, los de la denominada biomasa forestal primaria residual. Se analiza el papel de la biomasa en la economía forestal, así como las características de la oferta y la demanda del incipiente mercado ligado al aprovechamiento energético de este tipo de biomasa. Se discuten los principales factores determi-nantes de sus costes de producc...

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

    张婷; 余骏华; 戴国华

    2016-01-01

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

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

    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.

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

    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 ...

  13. VoIP technology comes of age.

    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

  14. Integrating Existing Software Toolkits into VO System

    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...

  15. Magnetic Irreversibility in VO2/Ni Bilayers

    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.

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

    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.

  17. Scalable architecture for VoIP privacy

    Medvinsky, Alexander

    2001-07-01

    An access network for Voice over IP (VoIP) clients (e.g. DOCSIS-based HFC network) often provides a privacy service. However, such a privacy service is limited only to that access network. When VoIP packets are carried over an open IP network or over a network with some connections to the Internet, it is desirable to provide an end-to-end privacy service where each VoIP packet is encrypted at the source and decrypted at the terminating endpoint. Clearly, public key encryption cannot be applied to each voice packet; the performance would be unacceptable regardless of the choice of a public key algorithm. The only alternative is for the two VoIP endpoints to negotiate a shared symmetric key. Since VoIP connections are established only for duration of a phone call, the end-to-end key negotiation needs to occur during each call setup. And it should not noticeably delay the call setup phase. In order to provide end-to-end privacy, it is not sufficient to encrypt all messages between the two endpoints. It is important that the two endpoints authenticate each other - validate each other's identity. Without authentication an adversary might trick two VoIP clients to negotiate keys with her and then sit in the middle of their conversation and record each VoIP packet, before forwarding it to the intended destination. However, direct authentication of the two VoIP endpoints is not always possible in telephony networks - in particular when caller ID blocking services are enabled. To support such anonymity services, it may be sufficient to authenticate not the identity of the caller but the fact that it is a valid subscriber and that all subsequent signaling and voice traffic will be coming from the same source. The PacketCable specifications provide an example of a VoIP architecture with end-to-end privacy that meets the above stated criteria. This paper describes the PacketCable end-to-end privacy approach and suggests additional mechanisms that may be used to further

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

    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.

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

    TATIANA RODRIGUEZ CHAPARRO

    2010-01-01

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

  20. VoIP:n tietoturva ja soveltuvuus julkishallintoon

    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...

  1. VoIP - new way of communication

    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...

  2. Understanding VoIP from Backbone Measurements

    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 ...

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

    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....

  4. 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

    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...

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

    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...

  6. Viabilidad de una planta de biomasa forestal para la producción de energía eléctrica

    Alonso Aguado, Antonio

    2014-01-01

    Este Proyecto estudia la implantación de una central termoeléctrica para la generación de energía en la provincia de Orense. Se trata de una instalación que hace uso de biomasa forestal con el fin de producir energía eléctrica renovable de una manera responsable. En primer lugar se estudia en profundidad la disponibilidad de la biomasa presente en la región que dará lugar al emplazamiento de la instalación, en pos de una posterior toma de decisión acerca del correcto dimensionamiento de la p...

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

    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...

  8. Digestión anaerobia y efecto del pretratamiento con microondas sobre la biomasa algal procedente de lagunas de alta carga

    Cordón Casero, Sabina

    2011-01-01

    Las lagunas de alta carga son un sistema de depuración de las aguas residuales basado en la relación simbiótica entre microorganismos que degradan la materia orgánica y microalgas que aportan oxígeno y nutrientes. El efluente de este tipo de lagunas contiene una gran concentración de materia en suspensión, formada principalmente por biomasa algal. Durante la última década, ha habido un creciente interés en la investigación del potencial energético de los cultivos de biomasa algal, para la ...

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

    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...

  10. Conversión hidrotérmica suscritica de residuos orgánicos y biomasa. mecanismos de reacción

    Castro Vega, Alejandro Amadeus; Rodríguez Varela, Luis Ignacio; Díaz Velásquez, José de Jesús

    2010-01-01

    La conversión hidrotérmica es un procedimiento que emula el proceso natural de conversión de la materia orgánica en un biocrudo con propiedades fisicoquímicas similares a las del petróleo. La transformación artificial de biomasa requiere conocer previamente las rutas de reacción y productos prevalentes. En la conversión de celulosa, el principal componente de la biomasa, se presenta despolimerización por hidrólisis y se obtienen oli- gosacaridos, los cuales presentan deshidratación y condens...

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

    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...

  12. DISTRIBUCIÓN DE BIOMASA Y ACUMULACIÓN DE PLOMO EN CALABACITA (Cucurbita pepo L.) CULTIVADA EN SUELO CONTAMINADO

    Floriberto Solis-Mendoza; Jaime Sahagún-Castellanos; Clemente Villanueva-Verduzco; María Teresa Colinas-León; María del Rosario García-Mateos

    2012-01-01

    Se estudió el efecto del suelo contaminado con plomo en el híbrido experimental de calabacita (Cucurbita pepo L.) denominado 'Termo'. Se cultivó calabacita en bolsas negras de polietileno, a cielo abierto. Se evaluaron las variables distribución de la producción de biomasa, altura de planta, contenido de clorofila y acumulación de plomo en raíz, tallo, hoja, flor y fruto. Los tratamientos fueron 0, 65, 300 y 1000 ppm de plomo aplicado al suelo a través de Pb(NO3)2. Se utilizó un diseño experi...

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

    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. ...

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

    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...

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

    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...

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

    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 ...

  17. Electrochemical catalytic activity of tungsten trioxide- modified graphite felt toward VO2+/VO2+ redox reaction

    A novel graphite felt electrode modified with tungsten trioxide (WO3) was developed to improve the electrochemical performance of graphite felt toward the VO2+/VO2+ redox pair. WO3 was prepared using a hydrothermal method, and the morphology of WO3 structures was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical property of WO3-modified graphite felt toward VO2+/VO2+ was carefully characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The hydrogen-vanadium redox flow battery (H-VRFB) test indicates that single cells using 1.1 mg cm−2 WO3-modified graphite felt exhibited excellent performance at 70 mA cm−2, and the corresponding coulombic, voltage, and energy efficiencies were 99.1%, 88.66% and 87.86%, respectively

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

    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.

  19. How To: Be VoIP-Savvy

    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…

  20. Is VoIP Worth It?

    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…

  1. VoIP in a Campus Environment

    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,…

  2. Polycrystalline VO2 thin films via femtosecond laser processing of amorphous VO x

    Charipar, N. A.; Kim, H.; Breckenfeld, E.; Charipar, K. M.; Mathews, S. A.; Piqué, A.

    2016-05-01

    Femtosecond laser processing of pulsed laser-deposited amorphous vanadium oxide thin films was investigated. Polycrystalline VO2 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 VO2, thus presenting a pathway for the growth of crystalline vanadium dioxide films on low-temperature substrates.

  3. Using VoIP to compete.

    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

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

    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.

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

    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...

  6. Epitaxial stabilization and phase instability of VO2 polymorphs.

    Lee, Shinbuhm; Ivanov, Ilia N; Keum, Jong K; Lee, Ho Nyung

    2016-01-01

    The VO2 polymorphs, i.e., VO2(A), VO2(B), VO2(M1) and VO2(R), have a wide spectrum of functionalities useful for many potential applications in information and energy technologies. However, synthesis of phase pure materials, especially in thin film forms, has been a challenging task due to the fact that the VO2 polymorphs are closely related to each other in a thermodynamic framework. Here, we report epitaxial stabilization of the VO2 polymorphs to synthesize high quality single crystalline thin films and study the phase stability of these metastable materials. We selectively deposit all the phases on various perovskite substrates with different crystallographic orientations. By investigating the phase instability, phonon modes and transport behaviours, not only do we find distinctively contrasting physical properties of the VO2 polymorphs, but that the polymorphs can be on the verge of phase transitions when heated as low as ~400 °C. Our successful epitaxy of both VO2(A) and VO2(B) phases, which are rarely studied due to the lack of phase pure materials, will open the door to the fundamental studies of VO2 polymorphs for potential applications in advanced electronic and energy devices. PMID:26787259

  7. MGCP在VoIP中的应用及优势

    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.

  8. Electrical oscillation in Pt/VO2 bilayer strips

    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

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

    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.

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

    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.

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

    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...

  12. Modular VO oriented Java EE service deployer

    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

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

    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.

  14. Patterning of epitaxial VO2 microstructures by a high-temperature lift-off process

    The growing field of oxide-electronics demands adequate fabrication methods that do not impair the material’s beneficial properties. To this end, we present a modified lift-off lithography method replacing the conventional polymer mask with an AlOx based mask. It can sustain the high-temperature and reactive gasses conditions commonly needed for oxide deposition, and is effectively wet-etched in dilute NaOH solutions. Here we demonstrate patterning of VO2 films. With its metal–insulator transition (MIT) near room temperature, it is attractive for various applications including sensors and transistors. But patterning is challenging since its properties are very sensitive to fabrication processes. We demonstrate patterning of 3 μm wide VO2 electrodes and show they preserve the MIT magnitude and epitaxial growth of the non-patterned films. Some thinning of the VO2 is also observed. This process can be useful for patterning other materials that require harsh deposition conditions, and are resilient to low NaOH concentrations. (paper)

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

    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.

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

    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.

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

    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.

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

    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

  19. Korišćenje satelitskih snimaka za vođenje radne karte / Use of satellite images in situation map design

    Miodrag D. Regodić

    2010-01-01

    Radna karta je nezaobilazan činilac pri neprekidnom praćenju situacije i donošenju odluka u svim periodima pripreme, vođenja i otklanjanja posledica ratovanja. Zato je neophodno da sadržaj radne karte omogući vizuelno jasan, pravovremen, tačan i proveren pregled situacije. Do podataka za radnu kartu dolazi se pomoću svih načina i sredstava za izviđanje i snimanje stanja i rasporeda snaga sukobljenih strana. Svi načini i sredstva za prikupljanje podataka za vođenje radne karte su značajni, jer...

  20. Steganography of VoIP streams

    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. Simulink based VoIP Analysis

    Singh, Hardeep; Mian, M

    2010-01-01

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

  2. Bezpečnost VoIP protokolů

    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. Realizace VoIP ústředny Asterisk

    Schön, Martin

    2011-01-01

    Bakalářská práce je rozdělena na dvě části, teoretickou a praktickou. V teoretické jsou rozebírány signalizační protokoly, protokol RTP pro přenos dat, VoIP ústředna Asterisk a jejich možnosti zabezpečení. V praktické části je popsána instalace ústředny Asterisk, provedena ukázka přesměrování hovorů. Ústředna byla spojena s adresářovým serverem LDAP pro správu uživatelů a Ejabberd pro zasílání textových zpráv protokolem XMPP. Dále byl nakonfigurován překlad SIP-SKYPE s využítím SiSky brány a ...

  4. Structural characterization of FeVO4 synthesized by co-precipitation method

    Bera, Ganesh; Sinha, Sourav; Rambabu, P.; Das, P.; Gupta, A. K.; Turpu, G. R.

    2016-05-01

    A Low temperature method for synthesizing triclinic FeVO4 nanoparticles is manifested through co-precipitation method. Three precursor materials taken for the synthesis are Iron Nitrate, Ammonium Metavanadate and NaOH along with DI water. The attained precipitate was dried at 100°C for overnight and calcined at different temperatures ranging from 400°C - 650°C. The achieved powdered materials are studied through X - ray diffraction and found to be in pure single phase of P-1 space group symmetry. The crystallite size measured through Scherrer's method is in found to be in the range of 40-60 nm. Raman spectroscopic studies were carried out at room temperature. Raman spectra is in agreement with the reported structural data of FeVO4.

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

    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.

  6. VoIP Regulation in Canada

    Marcel Boyer; Catherine Mercier

    2005-01-01

    The CRTC recently released Regulatory Framework for Voice Communication Services using Internet Protocol (Decision 2005-28), Telecom Decision CRTC 2005-28, setting out the details of the appropriate regulatory regime applicable to the provision of VoIP services. We present a brief overview of Decision 2005-28, we then consider the positions of incumbents and competitors, and finally we comment on the above interventions in light of the economic theory of regulation and the theory of strategic...

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

    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

  8. What are suspicious VoIP delays?

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    2010-01-01

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

  9. Cloudspace: virtual environments in the VO

    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.

  10. ESA Science Archives and associated VO activities

    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).

  11. UPORABA TEHNOLOGIJE VOIP NA MOBILNIH NAPRAVAH SYMBIAN

    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...

  12. Urchin-like m-LaVO4 and m-LaVO4/Ag microspheres: Synthesis and characterization

    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

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

    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

  14. Integrating legacy software toolkits into China-VO system

    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.

  15. Deployment of VoIP Technology: QoS Concerns

    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...

  16. Audio Codecs in VoIPv6: A Performance Analysis

    Monjur Ahmed; Mohammad Sarwar Hossain Mollah

    2014-01-01

    Audio communications in IP based networks have been revolutionized by the introduction of VoIP applications. High cost-efficiency has made VoIP to be the communication means in today’s world; and this trend is anticipated to be continued on an ongoing basis. The performance of VoIP significantly depends on the efficiency of the audio codecs used in any communication scenario which make the study on the performance issues of audio codecs in VoIP applications worth investigating. IPv6 is the ne...

  17. Evaluation of VoIP Security for Mobile Devices

    Nakarmi, Prajwol Kumar

    2011-01-01

    Market research reports by In-Stat, Gartner, and the Swedish Post and Telecom Agency (PTS) reveal a growing worldwide demand for Voice over IP (VoIP) and smartphones. This trend is expected to continue over the coming years and there is wide scope for mobile VoIP solutions. Nevertheless, with this growth in VoIP adoption come challenges related with quality of service and security. Most consumer VoIP solution, even in PCs, analog telephony adapters, and home gateways, do not yet support media...

  18. Direct synthesis of thermochromic VO2 through hydrothermal reaction

    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).

  19. Security Research on VoIP with Watermarking

    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.

  20. Photoemission study of TiO2/VO2 interfaces

    Maekawa, K; Takizawa, M.; Wadati, H.; Yoshida, T.; Fujimori, A.; Kumigashira, H.; Oshima, M.; Muraoka, Y.; Nagao, Y.; Hiroi, Z.

    2006-01-01

    We have measured photoemission spectra of two kinds of TiO$_2$-capped VO$_2$ thin films, namely, that with rutile-type TiO$_2$ (r-TiO$_2$/VO$_2$) and that with amorphous TiO$_2$ (a-TiO$_2$/VO$_2$) capping layers. Below the Metal-insulator transition temperature of the VO$_2$ thin films, $\\sim 300$ K, metallic states were not observed for the interfaces with TiO$_2$, in contrast with the interfaces between the band insulator SrTiO$_3$ and the Mott insulator LaTiO$_3$ in spite of the fact that ...

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

    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.

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

    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.

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

    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.

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

    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.

  5. Temeljna načela timskog rada

    Nikić, Mijo

    2004-01-01

    U članku su – interdisciplinarnim pristupom – obrađena temeljna načela timskog rada. Analizirane su zapreke i kočnice timskog rada, kompetencije potrebne za uspješno djelovanje radnog tima, motiviranje osoba u timskom radu te glavne oznake uspješnog vođe timskog rada. Doneseni su i savjeti sv. Petra apostola vođama Crkve, koji se mogu primijeniti na vođe bilo kojeg timskog rada. Ideje izložene u ovom članku trebale bi pomoći da više vrednujemo timski rad i postanemo što svjesniji dinamike i p...

  6. β-K(VO22(PO4

    Safa Ezzine Yahmed

    2013-01-01

    Full Text Available A new vanadium oxide, potassium bis(dioxovanadyl phosphate, β-K(VO22(PO4, has been synthesized by a solid-state reaction. In the title compound, the [V2PO8] framework is built up from infinite pyramidal [V2O8]∞ and [VPO7]∞ chains linked together by V—O—P bridges, leading to a three-dimensional framework which delimits two types of intersecting tunnels running along [100] and [010] in which the four unique K+ ions, showing coordination numbers of nine and ten, are located.

  7. VO-compliant workflows and science gateways

    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.

  8. The Effect of Habitual Smoking on VO2max

    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 (pBMI were independently related with VO2max (R2 = 0.642, SEE = 4.90, pBMI 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 of 1.71 ml/kg/min is noted. Adding pack.y data improves the accuracy of predicting the VO2max of smokers.

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

    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...

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

    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...

  11. 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

    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.

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

    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.

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

    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.

  14. Monitorování provozu VoIP pomocí technologie OnePK

    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....

  15. Regulatory legacy, VoIP adoption and investment incentives

    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.

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

    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

  17. VO2(B) nanospheres: Hydrothermal synthesis and electrochemical properties

    Monodisperse VO2(B) nanospheres with an average size of 100 nm were synthesized by hydrothermal method. Experiments showed that the surfactant octadecyl-amine played an important role during the formation of the nanospheres, and possible mechanism was suggested. Moreover, the potential uses of VO2 nanospheres were primarily probed as electrodes for lithium-ion batteries.

  18. Implementation of a Prototype VoIP System

    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.

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

    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.

  20. Fabrication of VO2-based multilayer structure with variable emittance

    Highlights: • Multilayer structures consisted of VO2 layer, HfO2 layer and Ag layer. • Influence of VO2 and HfO2 layer thickness on the emittance variability was studied. • Emittance variation of 0.55 and transition temperature (Tc) of 58 °C was obtained. • Multilayer structures with W-doped VO2 film were deposited. • Influence of W doping concentration on emittance variability was investigated. - Abstract: VO2 film holds promise for smart radiation device (SRD) use because of its infrared reflection change through the semiconductor-to-metal transition (SMT). In present study, a multilayer structure which consisted of VO2 layer, HfO2 layer and Ag layer was fabricated to achieve variable emittance based on the principle of reflection filter and SMT of VO2. It was found that with optimal 50 nm-thick VO2 layer, emittance of the multilayer structure could reversibly change from 0.13 at 30 °C to 0.68 at 80 °C with emittance variability of 0.55. Emittance hysteresis loop with transition temperature (Tc) of 58 °C and narrow width of 4 °C was obtained. Finally, multilayer structures with W-doped VO2 films were deposited and transition temperature decreased from 58 to 5 °C as W doping concentration increased from 0% to 3%, with Tc decreasing efficiency of −17.2 °C/at%. However, W doping also led to increased low temperature infrared absorption of VO2 film, which resulted in decreased emittance variability for the multilayer structure, from 0.55 to 0.37 as the W doping concentration in VO2 layer increase from 0% to 3%

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

    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.

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

    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.

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

    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.

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

    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. Reactive evaporation of anomalous blue VO2

    Thin films of vanadium dioxide exhibit a thermally induced semiconductor-to-metal phase transition near 670 C. In most deposition conditions, the transition is accompanied by large changes in optical properties at infrared wavelengths, but with only slight visible contrast. Recently, reactive evaporation at high temperatures and in stringent process conditions of so-called blue VO2 has been reported [G. A. Nyberg and R. A. Buhrman, J. Vac. Sci. Technol. A 2, 301 (1984)]. These films exhibit a striking blue-to-red transition in transmitted light. In this paper, a new technique for thin-film growth of anomalous vanadium dioxide will be presented. The primary steps in the process are the reactive evaporation of vanadium oxide at ambient temperature followed by anneal in flowing oxygen. Optical and microstructural data for material deposited on sapphire and fused quartz substrates will be compared to standard vanadium oxide

  6. Reinvestigation of the synthesis of LiFeVO4

    Highlights: → We reinvestigated the synthesis of the LiFeVO4 compound. → We demonstrate that the recently reported LiFeVO4 phase is not a pure phase. → We proved by Rietveld refinement that LiFeVO4 is a mixture ofLiVO3 and Fe2O3. → We noticed some attempts to fraud (modification of the powder pattern) . - Abstract: The synthesis of LiFeVO4 composition has been performed in air starting from Li2CO3, Fe2O3, and V2O5 and using the standard solid-state reaction route reported by Refs. . Identical X-ray diffraction pattern has been obtained, however our careful analysis with MDI Jade 5.0 software does not agree with previously reported pure LiFeVO4 samples. The powder pattern has been perfectly indexed using the single crystal data of LiVO3 (C2/c, a = 10.16718 A, b = 8.415725 A, c = 5.884155 A and β = 110.489o) and α-Fe2O3 (R-3c, a = 5.035 A, c = 13.75 A).

  7. SIP-CCME cooperation in multimedia VoIP network

    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.

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

    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.

  9. Analysis of data communications security for VoIP protocols

    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 ...

  10. Access Regulation and the Adoption of VoIP

    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 ...

  11. Improvement on QoS of VoIP

    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.

  12. VoIP Malware: Attack Tool & Attack Scenarios

    Nassar, Mohamed; State, Radu; Festor, Olivier

    2009-01-01

    With the appearance of new Internet services like Voice over IP and IP television, malwares are in the way to update and extend their targets. In this paper, we discuss the emergence of a new generation of malwares attacking VoIP infrastructures and services. Such malwares constitute a real threat to the currently deployed VoIP architectures without strong security measures in place. We present one implemented environment that can be used to evaluate such attacks. Our ``VoIP bots'' support a ...

  13. 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

    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.

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

    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.

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

    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...

  16. Audio CAPTCHA for SIP-Based VoIP

    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.

  17. VoIP现状及安全性研究

    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.

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

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

    2015-06-01

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

  19. Two-dimensional VO2 photonic crystal selective emitter

    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

  20. A European Perspective of VoIP in Market Competition

    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...

  1. Mathematical Representation of VoIP Connection Delay

    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.

  2. 漫谈VoIP技术及应用

    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

  3. Future of VoIP over Wireless in Economic Downturn

    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...

  4. Implementasi Server VoIP Berbasis SIP Pada LAN Nirkabel

    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...

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

    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

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

    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.

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

    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.

  8. The Euro-VO Registry, Re-engineering the Back-end

    Arviset, C.; Perdikeas, M.; Osuna, P.; Gonzalez, J.

    2015-09-01

    The Euro-VO Registry, located, developed and operated at ESAC, is one of the full searchable registries available worldwide, gathering information about all VO-compliant resources. The Euro-VO Registry serves as a registration point for European - and other countries- VO actors and data centres wishing to publish VO services. It harvests other registries to ensure its completeness so VO applications developers and VO users can use it to discover all VO resources, from Europe and from all other VO projects. The Euro-VO Registry provides as well a harvesting interface to other registries in the world to make sure the European VO services are also included in all other worldwide full registries. In particular, the new Euro-VO registry will be supporting the new RegTAP search interface for the relational registry allowing arbitrary ADQL queries against its contents over a compliant TAP service. The recently obsolete (for future developments) SOAP-based legacy search interface will also be supported for backwards compatibility purposes. Furthermore, in the context of the IVOA, some quality control and curation procedures for the registry resources are being defined. The Euro-VO Registry implements these procedures to ensure the high quality of the VO resources it references. This paper gives an overview of the recent development of the new Euro-VO Registry, together with its new curation facilities, both of which are being performed under a contract awarded to Neuropublic, under ESA special initiative to Greece.

  9. Audio Codecs in VoIPv6: A Performance Analysis

    Monjur Ahmed

    2014-04-01

    Full Text Available Audio communications in IP based networks have been revolutionized by the introduction of VoIP applications. High cost-efficiency has made VoIP to be the communication means in today’s world; and this trend is anticipated to be continued on an ongoing basis. The performance of VoIP significantly depends on the efficiency of the audio codecs used in any communication scenario which make the study on the performance issues of audio codecs in VoIP applications worth investigating. IPv6 is the new version of IP, which will gradually replace the current IPv4 as the transition from IPv4 to IPv6 is already in place. This demands the scrutiny of the audio codecs being used in IPv4 to be tested for their compatibility in IPv6 in terms of desired performance. This paper presents the study on the performance of selected audio codecs that are widely used in VoIPv4. G.711, G.729A and G.723.1 codecs were chosen for the study in VoIPv6 based scenarios presented in this paper. The selected audio codecs were applied in IPv6 based voice communication network scenarios to determine their performance efficiency by observing various QoS parameters. The study was done by means of simulation using OPNET.

  10. Fair Scheduling for Delay-Sensitive VoIP Traffic

    Ahmed, Shawish; Jiang, Xiaohong; Horiguchi, Susumu

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

  11. The preparation of a plasmonically resonant VO2 thermochromic pigment

    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.

  12. The preparation of a plasmonically resonant VO2 thermochromic pigment

    Vanadium dioxide (VO2) undergoes a reversible metal-insulator transition, normally at ∼68 0C. 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. Synthesis and properties of solid solutions with perovskite structure in the SrVO3-EuVO3 system

    Investigation results of solid solutions Srsub(1-x)Eusub(x)VOsub(3) where a noticeable presence of defects in anion sublattice are presented. Solid solutions shown, are obtained by sintering of strontium hypovanadate SrVO3 and europium orthovanadate EuVO3 in vacuum at 1673 K during 36 hours. Existence of Srsub(1-x)Eusub(x)VOsub(3) solid solutions with the perovskite structure of two types: cubic (03-EuVO3 system. It is shown that in Srsub(1-x)Eusub(x)VOsub(3) solid solutions, as well as in EuVO3, three-valent state of Eu is preserved. Transition from the metal conductivity character to the semiconductive one is carrierd out at xsub(k) approximately 0.75. Concentration and temperature dependences of specific electric resistance of solid solutions are presented

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

    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.

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

    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。

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

    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.

  17. 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

    César A García-Ubaque; Martha L Vaca-Bohórquez; Gabriel F Talero

    2013-01-01

    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 alternativo...

  18. Metodología para la Optimización del Aprovechamiento Energético de los Recursos de Biomasa. Aplicación a la Comunidad Valenciana.

    Alfonso Solar, David

    2013-01-01

    La masiva implementación de recursos energéticos distribuidos y renovables es la tendencia actual para incrementar la eficiencia, sostenibilidad y fiabilidad del suministro energético y la independencia de fuentes externas. La biomasa es un recurso renovable, distribuido y abundante en España, aunque en la actualidad su uso con fines energéticos es muy limitado y poco competitivo frente a otras fuentes de energía renovable. La implementación masiva de aplicaciones de biomasa...

  19. Componente 1: Apoyo en el desarrollo de energías renovables, eficiencia energética y bioenergía para la provincia de Buenos Aires: Estudio de la biomasa forestal y agroindustrial

    Carlos Pastor

    2010-01-01

    El presente informe tiene como objeto presentar varios tópicos vinculados a la biomasa forestal y forestoindustrial y su aprovechamiento energético en términos de sostenibilidad. Inicialmente, se presenta la caracterización de la biomasa como remanente de una actividad productiva; y la tipología, localización y volúmenes promedios potenciales de la misma en la Provincia de Buenos Aires, a los efectos de visualizar en tiempo y forma, las posibilidades bioenergéticas de esta fuente natural....

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

    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...

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

    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 ...

  2. Estudio de impacto ambiental de planta de tratamiento de biomasa para la producción de energía eléctrica en Garray (Soria)

    Gallego Ciprés, Oscar

    2013-01-01

    TRABAJO RECOMENDADO POR EL CENTRO Las necesidades energéticas de la economía actual implicarán la construcción, en los próximos años, de plantas para el aprovechamiento de la biomasa con fines energéticos. Los Graduados en Ingeniería Forestal: Industrias Forestales adquieren entre sus competencias formativas aquellas relacionadas con la xiloenergética, por ello, a través del presente TFG se aborda la redacción del Estudio de Impacto Ambiental de una planta de generación de energía eléctric...

  3. Metodología didáctica para el análisis de datos cualitativos en investigaciones orientadas al aprovechamiento de biomasa

    Marín López, Angie; Hernández Rangel, Elybe; Flores Quintero, Jesús Enrique

    2015-01-01

    El objetivo de este artículo consiste en proponer una metodología para el abordaje cualitativo del proceso de organización e interpretación de datos, orientada a estudiantes y profesores que conforman el grupo de investigación “aprovechamiento energético de biomasa residual” de una universidad de Venezuela. La investigación se insertó dentro del paradigma cualitativo; la metodología se desarrolló mediante la formulación de procedimientos para tres etapas claves en el análisis de datos cualita...

  4. VALORIZACIÓN INTEGRAL DE LA BIOMASA LEÑOSA AGROFORESTAL A LO LARGO DEL GRADIENTE ALTITUDINAL EN CONDICIONES MEDITERRÁNEAS

    FERNÁNDEZ PURATICH, HARALD WILSON

    2013-01-01

    La biomasa leñosa como recurso material o bioenergético varía principalmente según especie, condiciones ambientales que influyen en su producción y dispersión en el territorio. La estimación de la disponibilidad y aptitud de este recurso es hoy en día crucial para el desarrollo sostenible del sector agroforestal y, en concreto, de la cadena de valor monte-industria-consumo. Debido a la dispersión de esta fuente de materia prima en el territorio y a los altos costes log...

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

    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

  6. Densidad y biomasa de macroinvertebrados acuáticos derivantes en una quebrada tropical de montaña (bogotá, colombia)

    2013-01-01

    Se estimó la variación en la densidad de deriva de macroinvertebrados acuáticos y suaporte de materia orgánica en términos de biomasa de diferentes estados inmadurose imagos, en un tramo de una quebrada tropical de montaña ubicada en los cerrosorientales de Bogotá – Colombia y durante eventos de altas y bajas precipitaciones.Se colectó un total de 96 taxones de los cuales el más abundante fue Simulium con194 individuos (abundancia total). La densidad de deriva al igual que el aporte debiomasa...

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

    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...

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

    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...

  9. Sistema de calefacción para unifamiliar mediante energías renovables (solar, biomasa y geotérmica)

    Úriz Larrea, Aitor

    2010-01-01

    Este proyecto fin de carrera tiene como objeto el diseñar y valorar la instalación de calefacción y agua caliente sanitaria a instalar en una vivienda unifamiliar adosada, situada en Artajona (Navarra), utilizando para ello estas energías renovables: solar térmica (con apoyo de caldera de gasoil), biomasa y bomba de calor geotérmica. Se proyectará la instalación para cada tipo de las energías mencionadas y se mostrarán las ventajas y desventajas de cada una.

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

    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,...

  11. Situación actual y perspectivas de futuro de la hibridación térmica solar con biomasa forestal en España

    Turrado Fernández, Sandra

    2014-01-01

    La actual preocupación por el cambio climático y por la necesidad de buscar alternativas sostenibles a los combustibles fósiles ha llevado a la Unión Europea al establecimiento de una serie de objetivos en materia de medio ambiente y energías renovables para el año 2020. La hibridación térmica solar con biomasa forestal se presenta como una tecnología con un papel importante en el cumplimiento de dichos objetivos, por lo que este estudio analizará las posibilidades de su implementación en Esp...

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

    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...

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

    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.

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

    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.

  15. Právo na asistovanou reprodukci jako základní lidské právo?

    Doležal, Adam; Doležal, Tomáš

    Bratislava: Wolters Kluwer, 2014 - (Humeník, I.; Szaniszló, I.; Zoláková, Z.), s. 10-26 ISBN 978-80-8168-035-9. [Reprodukčné zdravie ženy v centre záujmu - Právne, bioetické, medicínske a psychosociálne aspekty starostlivosti o ženské zdravie. Košice (SK), 10.04.2014-11.04.2014] R&D Projects: GA ČR GAP408/12/2564 Institutional support: RVO:68378122 Keywords : European Court of Human Rights * access to assisted reproduction * In Vitro Fertilization Subject RIV: AG - Legal Sciences

  16. Právo na informace jako základní lidské právo

    Kolman, Jiří

    Brno: Masarykova univerzita, 2015 - (Večeřa, M.; Stachoňová, M.; Hapla, M.), s. 154-164. (Scientia. Řada teoretická. 530). ISBN 978-80-210-8001-0. [Weyrův den právní teorie. Brno (CZ), 05.06.2015-] R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : right to information * basic human rights * freedom of information and institutions of the European Union * EU administrative law * democracy * public international law * diplomacy * supranacionalism * intergovernmentalism Subject RIV: AG - Legal Sciences

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

    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...

  18. 公用信道技术在VoIP中的应用

    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.

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

    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.

  20. Electronic structure and insulating gap in epitaxial VO2 polymorphs

    Shinbuhm Lee

    2015-12-01

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

  1. Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition

    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

  2. Structural characterization of PrVO3 epitaxial thin films

    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...

  3. Thermochromic characteristics of Ti-doped VO2 thin film

    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.

  4. Proposal of Secure VoIP System Using Attribute Certificate

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

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

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

    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.

  6. 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

    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

  7. La biomasa forestal aplicada a la obtención de energía térmica como base para el desarrollo rural de zonas desfavorecidas. Aplicación en el municipio de El Espinar, Segovia

    Vignote Peña, Santiago; Ambrosio Torrijos, Yolanda; Lozano Piedras, Rebeca; Martín Larrañaga, Marcos; Martinez Rojas, Isaac; Leite, Angelo

    2013-01-01

    Se describe una metodologia basada en el estudio de la oferta de biomasa forestal y la demanda energética de un determinado municipio, para buscar el mejor aprovechamiento energético termico que facilite el desarrollo de una determinada región

  8. Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition

    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.

  9. Successive phase transitions in the orthovanadate TmVO3

    Sarkar, Tapati; Ivanov, Sergey A.; Bazuev, G. V.; Nordblad, Per; Mathieu, Roland

    2015-09-01

    Synthesis and crystal structure, magnetization and heat capacity measurements of phase pure polycrystalline TmVO3 are reported. TmVO3 was stabilized in the orthorhombic structure by thermal treatment of the precursor TmVO4 in a reducing atmosphere. Magnetization and heat capacity measurements reveal the presence of several successive structural and magnetic phase transitions in this compound. At T = 108 K, the sample undergoes a transition from a paramagnetic state to an antiferromagnetic state, followed by a second transition at 78 K which is related to spin and orbital reorientation. The heat capacity measurements reveal the presence of a third transition in the paramagnetic state (at T = 175 K), which corresponds to a structural phase transition and orbital ordering. At low temperatures (~15 K) and weak fields, there is an anomaly in the magnetization, which may be associated with antiferromagnetic short range ordering of the Tm3+ ions.

  10. Successive phase transitions in the orthovanadate TmVO3

    Synthesis and crystal structure, magnetization and heat capacity measurements of phase pure polycrystalline TmVO3 are reported. TmVO3 was stabilized in the orthorhombic structure by thermal treatment of the precursor TmVO4 in a reducing atmosphere. Magnetization and heat capacity measurements reveal the presence of several successive structural and magnetic phase transitions in this compound. At T = 108 K, the sample undergoes a transition from a paramagnetic state to an antiferromagnetic state, followed by a second transition at 78 K which is related to spin and orbital reorientation. The heat capacity measurements reveal the presence of a third transition in the paramagnetic state (at T = 175 K), which corresponds to a structural phase transition and orbital ordering. At low temperatures (∼15 K) and weak fields, there is an anomaly in the magnetization, which may be associated with antiferromagnetic short range ordering of the Tm3+ ions. (paper)