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O'3-Na(x)VO2 system: a superstructure for Na(1/2)VO2.  

Science.gov (United States)

The electrochemical cycling in a sodium battery of the lamellar oxide NaVO(2) is reversible in the Na(x)VO(2) composition range 1/2 ? x ? 1. The complex electrochemical curve reveals the presence of several transitions taking place during deintercalation. With the help of in situ X-ray diffraction, we observed the structural transitions taking place between Na(2/3)VO(2) and Na(1/2)VO(2). The diffractograms show the presence of several monophasic domains separated by biphasic domains. All phases present a monoclinic distortion of the ?-NaFeO(2) structure in the composition range 1/2 ? x ? 2/3. Moreover the presence of a superstructure is evidenced for Na(1/2)VO(2). It is the first time that an ordered structure is reported at the Na(1/2)MO(2) composition with an O'3 oxygen stacking. A thorough investigation of electrochemically obtained O'3-Na(1/2)VO(2) was performed. The structure refinement reveals the existence of a sodium/vacancy ordering, with a peculiar arrangement of the V-V distances hinting at a pairing of vanadium atoms. Our first measurements of the physical properties of O'3-Na(1/2)VO(2) show a semiconductor behavior and a complex thermal dependence of the magnetic susceptibility related to the pairing of the vanadium atoms. PMID:23009092

Didier, Christophe; Guignard, Marie; Darriet, Jacques; Delmas, Claude

2012-10-15

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Interaction in the FeVO4-NaOH-NaCl-H2O system  

International Nuclear Information System (INIS)

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 ?=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

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The investigation on NaVO3-NaHCO3-H2O system  

International Nuclear Information System (INIS)

The solubility of sodium vanadate and sodium bicarbonate in the NaVO3-NaHCO3-H2O system has been investigated at 293-323 K. On the base of the obtained results a polythermal section of the system has been drawn. The change of mutual salt concentrations (in mol/dm3) with temperature has been described with appropriate mathematical equations. Also, the equations describing the dependence of density of the solutions on temperature, have been presented. (author). 9 refs, 1 fig., 1 tab

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Orbital polarization in LiVO$_2$ and NaTiO$_2$  

CERN Document Server

We present a band structure study of orbital polarization and ordering in the two-dimensional triangular lattice transition metal compounds LiVO_2 and NaTiO_2. It is found that while in NaTiO_2 the degeneracy of t_{2g} orbitals is lifted due to the trigonal symmetry of the crystal and the strong on cite Coulomb interaction, in LiVO_2 orbital degeneracy remains and orbital ordering corresponding to the trimerization of the two-dimensional lattice develops.

Ezhov, S Y; Pen, H F; Khomskii, D I; Sawatzky, G A

1997-01-01

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Photoluminescence properties of NaSr(P, V)O4:Eu3+ phosphors.  

Science.gov (United States)

Eu3+ activated NaSr(P,V)O4 phosphors have been synthesized using solid state reaction method and further characterized for their structure and optical properties using different techniques such as X-ray diffraction, scanning electron microscopy, photolumniscenec excitation, emission, and chromaticity coorrdinate analysis, etc. Material shows a broad excitation peak (monitored for lambda(ems) = 613 nm) lying in the 300-360 nm region and gives intense transitions (lambda(exc) = 320 nm) namely 5D0 --> 7F1 at 590 nm, 5D0 --> 7F2 at 613 nm, 5D0 --> 7F3 at 650 nm, and 5D0 --> 7F4 at 700 nm due to Eu3+ ion. Our results show that replacement of the PO4(3-) ions with isomorphic VO4(3-) ions improves the structural stability and the overall intensity of the emission. The maxium emission intensity is achieved for the NaSr(P0.4, V0.6)O4:Eu3+ phosphor. An estimated increase of an order is attained for the NaSr(P0.4, V0.6)O4:Eu3+ phosphor as compared to NaSrPO4:Eu3+ or NaSrVO4:Eu3+ phosphor. The chromaticity coordinate of the phosphor (0.68, 0.31) lies well within the red region and suggest that the material could be an alternative red phosphor for lighting and display applications. PMID:23882793

Lee, Dong Gi; Singh, S K; Moon, Chuer Hyun; Yi, Soung Soo; Jang, Kiwan; Shin, Dong-Soo; Jeong, Jung Hyun; Bae, Jong-Seong

2013-08-01

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Relação entre modificações cinemáticas da corrida e o tempo limite na vVO2máx / Relationship between running kinematic changes and time limit at vVO2max  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A corrida realizada na velocidade do consumo máximo de oxigênio (vVO2máx) pode ocasionar modificações nos parâmetros cinemáticos e assim, aumentar o custo energético ao longo do tempo. O objetivo do presente estudo foi analisar características cinemáticas da articulação do tornozelo e joelho durante [...] a corrida na vVO2máx e a relação entre modificações cinemáticas e o tempo limite na vVO2máx(Tlim). Onze voluntários ativos fisicamente foram submetidos a um teste incremental de corrida para determinar a vVO2máx e posteriormente, a um teste de velocidade constante na vVO2máx. As variáveis cinemáticas foram adquiridas através de filmagem bidimensional a 210Hz no plano sagital esquerdo, no estágio inicial e final da corrida. De todas as variáveis angulares analisadas, a máxima plantiflexão no balanço (p Abstract in english Exhaustive running at maximal oxygen uptake velocity (vVO2max) can alter running kinematic parameters and increase energy cost along the time. The aims of the present study were to compare characteristics of ankle and knee kinematics during running at vVO2max and to verify the relationship between c [...] hanges in kinematic variables and time limit (Tlim). Eleven male volunteers, recreational players of team sports, performed an incremental running test until volitional exhaustion to determine vVO2max and a constant velocity test at vVO2max. Subjects were filmed continuously from the left sagittal plane at 210 Hz for further kinematic analysis. The maximal plantar flexion during swing (p

Leonardo, De Lucca; Sebastião Iberes Lopes, Melo.

7

Comparison of the effect of VOSO4, Na3VO4 and NaVO3 on proliferation, viability and morphology of H35-19 rat hepatoma cell line.  

Science.gov (United States)

This study presents the investigation and comparison the influence of VOSO4 [V(IV)I, Na3VO4 and NaVO3 [V(V)] in the range of 0.5-20.0 microM on the rat hepatoma cell line H35-19. The cells were tested with crystal violet (N-hexamethylpararosaniline), and counted in a Bürker chamber to determine their rate of proliferation, while the survival level was established with neutral red and MTT [bromide 3-(4,5-dimetyltioazo-2)-2,5-diphenyl-tetrazole]. Parallel independent pathomorphological studies with electron microscopic examinations were done. We found progressive growth inhibition of rat hepatoma H35-19 cells within the range 0.5-20.0 concentrations of three vanadium salts. The most effective (and/or toxic) was NaVO3, whereas VOSO4 showed a relatively mild action. As compared with metavanadate or vanadyl sulphate and especially organic vanadium derivatives, previously studied by the same authors under similar experimental conditions, sodium orthovanadate showed an intermediate effect. Electron microscopic examinations confirmed these results. Vanadium salts in low concentration in medium (0.5 microM) were observed to normalize cell morphology. Higher doses of vanadium salts (greater than 2.5 or 5.0 microM) resulted in damaging cell organelles and the more cytotoxic the compounds seemed to be. PMID:17585542

Kordowiak, Anna M; Klein, Andrzej; Goc, Anna; Dabro?, Wojciech

2007-01-01

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Selective solution-phase synthesis of BiOCl, BiVO4 and ?-Bi2O3 nanocrystals in the reaction system of BiCl3-NH4VO3-NaOH  

International Nuclear Information System (INIS)

In this study, we demonstrate a straightforward solution-phase method for the selective synthesis of BiOCl, BiVO4 and ?-Bi2O3 nanocrystals by simply manipulating the reaction temperature and the BiCl3-to-NaOH mole ratio in the reaction system of BiCl3-NH4VO3-NaOH. The experimental results revealed that BiOCl, as the sole product, was prepared when designating the reaction temperature ranging from room temperature to 100 deg. C, regardless of the BiCl3-to-NaOH mole ratio; on the other hand, BiOCl, BiVO4, and ?-Bi2O3 nanocrystals could be selectively prepared at 140-180 deg. C, depending on the BiCl3-to-NaOH mole ratio in solution. Significantly, we first report on fabricating ?-Bi2O3 sample, the high-temperature cubic phase commonly stabilized at 730-824 deg. C, at the low reaction temperature of 140-180 deg. C under solution-phase synthetic conditions. In addition, the ?-Bi2O3 sample exhibits strong emission at room temperature. - Graphical abstract: In this study, we demonstrate a straightforward solution-phase method for the selective synthesis of BiOCl, BiVO4 and ?-Bi2O3 nanocrystals by simply manipulating the reaction temperature and the BiCl3-to-NaOH mole ratio in the reaction system of BiCl3-NH4VO3-NaOH4VO3-NaOH

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Graphene Quantum Dots Coated VO2 Arrays for Highly Durable Electrodes for Li and Na Ion Batteries.  

Science.gov (United States)

Nanoscale surface engineering is playing important role in enhancing the performance of battery electrode. VO2 is one of high-capacity but less-stable materials and has been used mostly in the form of powders for Li-ion battery cathode with mediocre performance. In this work, we design a new type of binder-free cathode by bottom-up growth of biface VO2 arrays directly on a graphene network for both high-performance Li-ion and Na-ion battery cathodes. More importantly, graphene quantum dots (GQDs) are coated onto the VO2 surfaces as a highly efficient surface "sensitizer" and protection to further boost the electrochemical properties. The integrated electrodes deliver a Na storage capacity of 306 mAh/g at 100 mA/g, and a capacity of more than 110 mAh/g after 1500 cycles at 18 A/g. Our result on Na-ion battery may pave the way to next generation postlithium batteries. PMID:25531798

Chao, Dongliang; Zhu, Changrong; Xia, Xinhui; Liu, Jilei; Zhang, Xiao; Wang, Jin; Liang, Pei; Lin, Jianyi; Zhang, Hua; Shen, Ze Xiang; Fan, Hong Jin

2015-01-14

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A study of optical properties of Sm3+ ions in ?-Na3Y(VO4)2 single crystals  

International Nuclear Information System (INIS)

Single crystals of ?-Sm3+:Na3Y(VO4)2 have been grown by the flux growth method. The absorption (300 K) fluorescence (4.2 and 300 K) and excitation (7 and 300 K) spectra as well as the fluorescence dynamics of the Sm3+-doped title crystals are presented and analyzed in detail. The energy transfer between Sm3+–Sm3+ as well as from VO43? to Sm3+ were studied in detail. A Judd–Ofelt intensity analysis of the absorption (300 K) spectrum has been applied for determination of ?? parameters which in turn have been used in calculation of the radiative transition probability factor (A), fluorescence branching ratios (?), natural (radiative) lifetime of the 4G(4)5/2 level of Sm3+ and emission cross-section (?em). For the first time very large lifetimes of the Sm3+ fluorescence level have been observed. -- Highlights: • Single crystals of Sm3+-doped ?-Na3Y(VO4)2 have been grown by the flux growth method. • The room and low-temperature spectroscopic properties of the single crystals were investigated. • The decay time of the fluorescence level are larger than those earlier reported for some Sm3+ doped vanadate materials. • Sm-doped ?-NYV crystal is a new promising luminescence materials

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Properties of the Na3VO4-HCl-H2O system in the dependence on acidity and concentration of the sodium vanadate solution  

International Nuclear Information System (INIS)

Concentration of free hydrogen ions and the composition of sediments emerging in the Na3VO4 solution by addition of Sm3+ ions were studied as influenced by acidity and concentration of the solution. The system was studied at five constant concentrations of vanadium (0.08, 0.12, 0.175, 0.22 and 0.32 g.ion/l) at different pH. Samarium vanadate was precipitated from the Na3VO4-HCl-H2O equilibrium system by equimolecular solutions of Sm(NO3)3 in the ratio 1:1. In the alkaline region the processes of protonization and dimerization in diluted sodium vanadate solutions were simultaneous. In more concentrated solutions these processes were separated, since the increase in V concentration promoted protonization rather than dimerization, especially in aklakine solutions

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-06-15

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

International Nuclear Information System (INIS)

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

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EVALUACIÓN DE ÍNDICES DE CONVERSIÓN ENERGÉTICA EN LA PRODUCCIÓN DE GAS COMBUSTIBLE A PARTIR DE BIOMASA / EVALUATION THE RATES OF ENERGY CONVERSIONINTHE PRODUCTIONOFBIOMASSFUELGAS / DETERMINAÇÃOTAXAS DE CONVERSÃO DE ENERGIA NA PRODUÇÃO DE GÁS COMBUSTÍVEL DE BIOMASSA  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in portuguese Os rácios de conversão de energia em gaseificação de biomassa, permite comparações entre gaseificadores e decidir melhor desempenho em um processo industrial. A pesquisa utilizou um tipo de reactor experimental Imbert7 KW, a biomassa de bagaço de cana, madeira e alfarrobeira. Elemental análises fora [...] m realizadas e proximal, e os cálculos de equilíbrio de massa térmica na conversão de taxas volumétricas de energia e de massa (I).Os valores caloríficos de cada gás de biomassa, a uma temperatura mínima de 850 º C e 1050 º C a operação do reactor era óptimo: 3679 kJ / kg de carvão de alfarroba, 4,603 madeira Kj / Kg e 5.009 kJ / kg de bagaço cana. Enquanto as taxas de utilização volumétricasforam: carvão Kj/Nm3 alfarroba 3.509,39, 3.804,39 e 4.847,83 Kj/Nm3 bagaço de madeira Kj/Nm3 cana. Concluímos eficiência gaseificador é de 70%, a taxa de conversão é adequada para estimar a massa calorífica do gás combustível produzido pode ser recuperado em um valor de aquecimento de combustão do gás de síntese é poder cerca de 10% aquecimento a gás e perdas de calor são 30%. Abstract in spanish Los índices de conversión energética en la gasificación de biomasa, permitecomparaciones entregasificadores y obtenerelmejor desempeño enun proceso industrial. Se utilizó un reactor de prueba tipo Imbert de 7 KW y biomasa debagazo de caña de azúcar,madera y árbol de algarrobo. Se realizaron análisis [...] elementales, proximalesy los balances másicos y térmicos en el cálculo de los índices de conversión de energía volumétrica y másica ().Los valores del poder calorífico del gas generado a una temperatura mínima de 850ºC y óptima de 1050ºC, en el reactor fueron: 3679 Kj/Kg de carbón de algarrobo, 4603 Kj/Kg de madera y 5009 Kj/Kg de bagazo de caña. Mientras los índices de aprovechamiento volumétrico fueron: 3509,39 Kj/Nm3decarbón de algarrobo, 3804,39 Kj/Nm3demadera y4847,83 Kj/Nm3debagazo de caña de azúcar. Se concluye que una eficacia del 70% en el gasificador, el índice de conversión es apropiado para estimar el poder calorífico,la masa del gas producido combustible puede ser recuperada en una combustión, el poder calorífico del gas de síntesis es aproximadamente el 10% del poder calorífico de la gasolina y las pérdidas de calor son del 30%. Abstract in english The energy conversion ratios in biomass gasification, allows comparisons between gasifiers and decide best performing one in an industrial process. The research used a test reactor type Imbert 7 KW, biomass sugarcane bagasse, wood and carob tree. Elemental and proximal analyzes were performed and th [...] ermal mass balance calculations involved in the conversion rates volumetric energy and mass (I). The calorific values of each biomass gas at a minimum temperature of 850ºC and 1050ºC optimum reactor operation where: 36779 kJ/kg of coal carob, 4603 kJ/kg of wood and 5009 kJ/kg of bagasse cane. While volumetric utilization rateswhere: 3509.39 of coal carob, 3804.39 Kj/Nm3 wood and 4847.83 Kj/Nm3 sugarcane bagasse. We conclude gasifies efficiency is 70%, the conversion rate is appropriate for estimating the calorific mass of the fuel gas produced can be recovered in a combustion heating value of the synthesis gas is about 10% power gas heating and heat losses are 30%.

GERARDO, CABRERA C.; SANTIAGO, MADRIÑAN M.; DEYANIRA, MUÑOZ M..

2013-12-01

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A study of optical properties of Sm{sup 3+} ions in ?-Na{sub 3}Y(VO{sub 4}){sub 2} single crystals  

Energy Technology Data Exchange (ETDEWEB)

Single crystals of ?-Sm{sup 3+}:Na{sub 3}Y(VO{sub 4}){sub 2} have been grown by the flux growth method. The absorption (300 K) fluorescence (4.2 and 300 K) and excitation (7 and 300 K) spectra as well as the fluorescence dynamics of the Sm{sup 3+}-doped title crystals are presented and analyzed in detail. The energy transfer between Sm{sup 3+}–Sm{sup 3+} as well as from VO{sub 4}{sup 3?} to Sm{sup 3+} were studied in detail. A Judd–Ofelt intensity analysis of the absorption (300 K) spectrum has been applied for determination of ?{sub ?} parameters which in turn have been used in calculation of the radiative transition probability factor (A), fluorescence branching ratios (?), natural (radiative) lifetime of the {sup 4}G(4){sub 5/2} level of Sm{sup 3+} and emission cross-section (?{sub em}). For the first time very large lifetimes of the Sm{sup 3+} fluorescence level have been observed. -- Highlights: • Single crystals of Sm{sup 3+}-doped ?-Na{sub 3}Y(VO{sub 4}){sub 2} have been grown by the flux growth method. • The room and low-temperature spectroscopic properties of the single crystals were investigated. • The decay time of the fluorescence level are larger than those earlier reported for some Sm{sup 3+} doped vanadate materials. • Sm-doped ?-NYV crystal is a new promising luminescence materials.

Sobczyk, Marcin, E-mail: marcin.sobczyk@chem.uni.wroc.pl; Szyma?ski, Damian

2013-10-15

16

??????????? ???????? ??????? ??????? ??? ???????? ?? ????????? VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

?? VoIP (Voice Over IP) ?????????? ??? ???????? ??? ?? ??????????? ???????????? ????? ?.? ??????????? ??????? ???? ??? IP ?????? ???? ????? ?? ?????????. ?????? ??? ???????? ???????????? ???? ? ?????? ??? ??????????? ????????? ??????? VoIP ??????????? ???????? (Sitel,Polycom) ???? ??? ?...

???????, ????????????

2011-01-01

17

Calefaccion centralizada por biomasa, Cuéllar  

Directory of Open Access Journals (Sweden)

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 económica respecto a otros combustibles tradicionales. Su gran contribución medioambiental a la producción de energía. además de las ventajas sociales como la creación de puestos de trabajo y desarrollo de actividades alternativas en zonas agrícolas y forestales, hacen que esta instalación sirva de modelo para su desarrollo en otras poblaciones con potencial de biomasa.

Verdú Pérez, Jesús

2001-10-01

18

Hydrothermal preparation of BiVO4 powders  

International Nuclear Information System (INIS)

Monoclinic bismuth vanadate (BiVO4) powders were prepared by a mild hydrothermal method, using an aqueous solution of bismuth nitrate and two different vanadium sources (V2O5 and NaVO3). The characterization of as-prepared BiVO4 was carried out by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The results revealed that in the present work the temperature of 200 and 140 deg. C are sufficient to prepare phase pure BiVO4 powders from V2O5 and NaVO3, respectively. The BiVO4 sample prepared from V2O5 consists of an agglomeration of small rod-like particles. When BiVO4 was prepared from NaVO3, monoclinic BiVO4 powder with a plate form is obtained

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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  

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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.

Fabiana Andrade Machado

2013-03-01

20

Three-dimensional framework of uranium-centered polyhedra with non-intersecting channels in the uranyl oxy-vanadates A2(UO 2) 3(VO 4) 2O ( A=Li, Na)  

Science.gov (United States)

The uranyl vanadates A2(UO 2) 3(VO 4) 2O ( A=Li, Na) have been synthesized by solid-state reaction and the structure of the Li compound was solved from single-crystal X-ray diffraction. The crystal structure is built from ?1[UO] chains of edge-shared U(2)O 7 pentagonal bipyramids alternatively parallel to a?- and b?-axis and further connected together to form a three-dimensional (3-D) arrangement. The perpendicular chains are hung on both sides of a sheet ?2[(UO)(VO)2] parallel to (001), formed by U(1)O 6 square bipyramids connected by VO 4 tetrahedra, and derived from the autunite-type sheet. The resulting 3-D framework creates non-intersecting channels running down the a?- and b?-axis formed by empty face-shared oxygen octahedra, the Li + ions are displaced from the center of the channels and occupy the middle of one edge of the common face. The peculiar position of the Li + ion together with the full occupancy explain the low conductivity of Li 2(UO 2) 3(VO 4) 2O compared with that of Na(UO 2) 4(VO 4) 3 containing the same type of channels half occupied by Na + ions in the octahedral sites. Crystallographic data for Li 2(UO 2) 3(VO 4) 2O: tetragonal, space group I41/ amd, a=7.3303(5) Å, c=24.653(3) Å, V=1324.7(2) Å3, Z=4, ?mes=5.32(2) g/cm 3, ?cal=5.36(3) g/cm 3, full-matrix least-squares refinement basis on F2 yielded, R1=0.032, wR2=0.085 for 37 refined parameters with 364 independent reflections with I?2?(I).

Obbade, S.; Duvieubourg, L.; Dion, C.; Abraham, F.

2007-03-01

 
 
 
 
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Inclusão do equivalente do lactato sanguíneo O2 na regressão de intensidade de exercício VO2 aumenta o gasto energético de corrida e diminui sua precisão / Inclusion of blood lactate O2 equivalent in the VO2 exercise intensity regression increases the energy cost of running and lowers its precision / La inclusión del equivalente del lactato sanguíneo O2 en la regresión de intensidad de ejercicio VO2 aumenta el gasto energético de la carrera y disminuye su precisión  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese INTRODUÇÃO E OBJETIVOS: Investigar se a inclusão do equivalente energético de lactato sanguíneo (LS) em intensidades submáximas alteraria o gasto energético de corrida (Gc) estimado para corrida supramáxima de alta intensidade assim como sua precisão MÉTODOS: O Gc foi determinado a partir da curva d [...] e regressão de velocidade do VO2. Para cada sujeito, uma regressão alternativa foi estabelecida em que energia equivalente a 3 ml de O2 kg-1?mM-1 de LS foi adicionada ao VO2. Testes t pareados, correlações pareadas e plotagem de Bland-Altman foram utilizados para investigar se os dois métodos representam os mesmos fenômenos. RESULTADOS: Os principais achados foram que o Gc previsto para intensidades supramáximas incluídos entre 110 e 160% ao correspondente ao pico de VO2 dos indivíduos aumentou significativamente quando as medidas de LS foram incluídas nas regressões. A inclusão das medidas de LS também aumentaram a imprecisão do Gc a 110, 120, 130, 150 e 160%. CONCLUSÃO: Nossos resultados indicam que a inclusão do equivalente do lactato de O2 na regressão de intensidade de VO2-exercício aumenta o gasto energético e diminui sua precisão. Abstract in spanish INTRODUCCIÓN Y OBJETIVOS: Investigar si la inclusión del equivalente energético de lactato sanguíneo (LS), en intensidades submáximas, modificaría el gasto energético de la carrera (Gc), estimado para carrera supramáxima de alta intensidad, así como su precisión. MÉTODOS: El Gc fue determinado a par [...] tir de la curva de regresión de velocidad del VO2. Para cada individuo, se estableció una regresión alternativa en la cual energía equivalente a 3 ml de O2 kg-1?mM-1 de LS fue adicionada al VO2. Pruebas t por pares, correlaciones por pares y plotaje de Bland-Altman fueron utilizados para investigar si los dos métodos representan los mismos fenómenos. RESULTADOS: Los hallazgos principales fueron que el Gc previsto para intensidades supramáximas, incluidos 110% y 160% de lo que corresponde al pico de VO2 de los individuos, aumentó significativamente cuando las medidas de LS fueron incluidas en las regresiones. La inclusión de las medidas de LS también aumentó la imprecisión del Gc a 110%, 120%, 130%, 150% y 160%. CONCLUSIÓN: Nuestros resultados indican que la inclusión del equivalente del lactato de O2, en la regresión de intensidad de VO2-ejercicio, aumenta el gasto energético y disminuye su precisión. Abstract in english INTRODUCTION AND OBJECTIVES: Investigate whether the inclusion of the blood lactate (BL) energy equivalent at submaximal intensities would change the energy cost of running (CR) predicted to supramaximal high-intensity running as well as its precision. METHODS: The CR was determined from the slope o [...] f the VO2-speed regression. For each subject an alternative regression was established where an energy equivalent of 3 ml O2 kg-1?mM-1 BL was added to the VO2. Paired t-tests, pairwise correlations and Bland-Altman plots were used to investigate whether the two methods represent the same phenomena. RESULTS: The main findings were that CR predicted to supramaximal intensities comprised between 110% and 160% of that corresponding to the individuals' peak VO2, increased significantly when the BL measurements were included in the regressions. The inclusion of BL measurements also increased the imprecision of the CR at 110%, 120%, 130%, 150% and 160%. CONCLUSIONS: Our results indicate that inclusion of lactate O2 equivalent in the VO2-exercise intensity regression increases the energy cost of running and lowers its precision.

Victor Machado, Reis; Diogo Roberto, Oliveira; André Luiz, Carneiro; Tiago Manuel, Barbosa.

2013-12-01

22

Na2[(VO)2(HPO4)2C2O4].2H2O: crystal structure determination from combined powder diffraction and solid-state NMR.  

Science.gov (United States)

The vanadyl oxalatophosphate Na2[(VO)2(HPO4)2C2O4].2H2O has been synthesized by hydrothermal treatment. Its structure has been determined and refined by combining X-ray powder diffraction and solid-state NMR techniques. It crystallizes with monoclinic symmetry in space group P2(1), a = 6.3534(1) A, b = 17.1614(3) A, c = 6.5632(1) A, beta = 106.597(1) degrees . The structure is related to that of (NH4)2[(VO)2(HPO4)2C2O4].5H2O, which was previously reported. The vanadium phosphate framework consists of infinite [(VO)(HPO4)] chains of corner-sharing vanadium octahedra and hydrogenophosphate tetrahedra. The oxalate groups ensure the connection between the chains to form a 2D structure. The sodium ions and the water molecules are located between the anionic [(VO)2(HPO4)2C2O4]2- layers. The thermal decomposition has been studied in situ by temperature-dependent X-ray diffraction and thermogravimetry. It takes place in three stages, where the first two correspond to water removal and the last to the decomposition of the oxalate group and water elimination, leading to the final product NaVOPO4. PMID:16842011

Colin, J F; Bataille, T; Ashbrook, S E; Audebrand, N; Le Pollès, L; Pivan, J Y; Le Fur, E

2006-07-24

23

Study of NaxVO2 layered oxides : electrochemistry, structure and physical properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis is about the study of the lamellar oxides NaxVO2. Several phases have been obtained with different stacking of the [VO2] sheets: O3-NaVO2, P'3-Na0.56VO2 and P2-Na0.73VO2. These three materials have been the subject of an electrochemical study in sodium batteries coupled with in situ X-ray diffraction in order to understand the structural transitions taking place as a function of the composition. A superstructure appears at Na1/2VO2 for the three stackings. This composition has bee...

Didier, Christophe

2013-01-01

24

VoIP Security  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VOIP or Voice Over Internet Protocol is a common term for phone service over IP based networks. There are much information about VoIP and some of how VoIP can be secured. There is however no standard for VoIP and no general solution for VoIP Security. The security in VoIP systems today are often non existing or in best case weak and often based on proprietary solutions. This master thesis investigates threats to VoIP system and describes existing alternatives for securing VoIP as it is today....

Fontanini, Piero

2008-01-01

25

Three-dimensional framework of uranium-centered polyhedra with non-intersecting channels in the uranyl oxy-vanadates A2(UO2)3(VO4)2O (A=Li, Na)  

International Nuclear Information System (INIS)

The uranyl vanadates A2(UO2)3(VO4)2O (A=Li, Na) have been synthesized by solid-state reaction and the structure of the Li compound was solved from single-crystal X-ray diffraction. The crystal structure is built from ?1[UO5]4- chains of edge-shared U(2)O7 pentagonal bipyramids alternatively parallel to a-vector- and b-vector-axis and further connected together to form a three-dimensional (3-D) arrangement. The perpendicular chains are hung on both sides of a sheet ?2[(UO2)(VO4)2]4- parallel to (001), formed by U(1)O6 square bipyramids connected by VO4 tetrahedra, and derived from the autunite-type sheet. The resulting 3-D framework creates non-intersecting channels running down the a-vector- and b-vector-axis formed by empty face-shared oxygen octahedra, the Li+ ions are displaced from the center of the channels and occupy the middle of one edge of the common face. The peculiar position of the Li+ ion together with the full occupancy explain the low conductivity of Li2(UO2)3(VO4)2O compared with that of Na(UO2)4(VO4)3 containing the same type of channels half occupied by Na+ ions in the octahedral sites. Crystallographn the octahedral sites. Crystallographic data for Li2(UO2)3(VO4)2O: tetragonal, space group I41/amd, a=7.3303(5)A, c=24.653(3)A, V=1324.7(2)A3, Z=4, ?mes=5.32(2)g/cm3, ?cal=5.36(3)g/cm3, full-matrix least-squares refinement basis on F2 yielded, R1=0.032, wR2=0.085 for 37 refined parameters with 364 independent reflections with I>=2?(I)

26

Programación por metas Energía alternativa mediante biomasa.  

Directory of Open Access Journals (Sweden)

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

Guerrero Casas, Flor María

2003-01-01

27

Multicomponent polyanions. 40. A potentiometric and 51V NMR study of equilibria in the H+-H2VO4--C2O42- system in 0.6 M Na(Cl) medium  

International Nuclear Information System (INIS)

The speciation in the H+-H2VO4--C2O42- system was determined from potentiometric (glass electrode) and 51V NMR measurements. The study was performed in 0.6 M Na(Cl) medium at 25deg C. The potentiometric data cover the range 2+]+]+)p(H2VO4-)q(C2O42-)r, having the (p,q,r) values (2,1,2) and (2,1,1) with lg ?2,1,2 = 17.11 ± 0.01 and lg ?=2,1,1 = 13.07 ± 0.02 explained all potentiometric and NMR data within the -lg[H+] range covered. The errors given are 3?. The equilibrium conditions are illustrated in distribution and predominance diagrams and possible structures discussed. (author)

28

Segurança e qualidade de serviço em redes VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

O mundo assistiu a uma revolução na telefonia com o aparecimento do VoIP, adoptado pelas organizações, que viram nesta tecnologia a oportunidade de minimizar os custos nas comunicações internas e externas. Apesar das vantagens que o VoIP apresenta, este também tem desvantagens relativas à segurança, apresentando maiores riscos comparativamente com a telefonia tradicional. O VoIP, embora seja uma tecnologia recente, tem implementado mecanismos que garantem a seguran?...

Correia, Joana Isabel Ferreira Leite Da Cunha

2011-01-01

29

Hydrothermal preparation of BiVO{sub 4} powders  

Energy Technology Data Exchange (ETDEWEB)

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

Liu Jingbing; Wang Hao; Wang Shu; Yan Hui

2003-11-15

30

Potencial de producción de biomasa en una población natural de la ostra crassostrea rhizophorae, en la laguna grande de obispo, Golfo de Cariaco, Venezuela / Biomass production potential in a natural population of the oyster crassostrea rhizophorae in laguna grande de obispo; Cariaco Gulf; Venezuela / Potencial de produção de biomassa na população natural da ostra crassostrea rhizophorae, na lagoa grande de obispo, Golfo de Cariaco, Venezuela  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in portuguese A ostra Crassostrea rhizophorae é um bivalves de interesse comercial, comum nas comunidades de manglares no oriente da Venezuela. Para avaliar o potencial de geração de biomassa da espécie se realizaram amostras mensais desde maio de 2002 até maio de 2003, em duas estações da população natural de La [...] guna Grande do Obispo, estado Sucre, Venezuela. Utilizando um desenho de amostras aleatório simples se determinou a abundância e a biomassa de bivalves fixados a raízes de Rhizophora manglae, estimando a produção secundária pelo método da taxa específica de crescimento. Determinou-se uma densidade média de 818,13ind/m² de raiz com biomassa média em peso seco de 662,39g/m², sem diferenças significativas entre estações nem meses. Utilizando um modelo de crescimento com parâmetros finais de L¥= 87,68 e K= 0,19/mês, se obteve uma produção secundária total de 2.355,546g/m²/ano, sendo o intervalo de tamanho 50,01-60,00mm o que aportou a maior quantidade (382,353g/m²/ano). A máxima produção se obteve em jan-fev de 2003 (243,906g/m²/ano) e a mínima em mai-jun de 2002 (100,80g/m²/ano). A produção por indivíduo foi de 43,283g/m²/ano com a mesma tendência temporal da total. Ainda que não se determinasse correlação dos incrementos de produção com a temperatura e salinidade, a maior produção ocorreu durante a época de surgência costeira na zona. A relação produção/biomassa foi de 3,55/ano, resultados que indicam que C. rhizophorae apresenta um grande potencial para atividades de aqüicultura na zona por sua reprodução continua e altas taxas de crescimento e produtividade. Abstract in spanish La ostra Crassostrea rhizophorae es un bivalvo de interés comercial, común en las comunidades de manglar en el oriente de Venezuela. Para evaluar el potencial de generación de biomasa de la especie se realizaron muestreos mensuales desde mayo 2002 hasta mayo 2003, en dos estaciones de la población n [...] atural de Laguna Grande del Obispo, estado Sucre, Venezuela. Utilizando un diseño de muestreo al azar simple se determinó la abundancia y la biomasa de bivalvos fijados a raíces de Rhizophora manglae, estimando la producción secundaria por el método de la tasa específica de crecimiento. Se determinó una densidad promedio de 818,13ind/m² de raíz con biomasa promedio en peso seco de 662,39g/m², sin diferencias significativas entre estaciones ni meses. Utilizando un modelo de crecimiento con parámetros finales de L¥= 87,68 y K= 0,19/mes, se obtuvo una producción secundaria total de 2355,546g/m²/año, siendo el intervalo de talla 50,01-60,00mm el que aportó la mayor cantidad (382,353g/m²/año). La máxima producción se obtuvo en ene-feb 2003 (243,906g/m²/año) y la mínima en may-jun 2002 (100,80g/m²/año). La producción por individuo fue de 43,283g/m²/año con la misma tendencia temporal de la total. Aunque no se determinó correlación de los incrementos de producción con la temperatura y salinidad, la mayor producción ocurre durante la época de surgencia costera en la zona. La relación producción/biomasa fue de 3,55/año, resultados que indican que C. rhizophorae presenta un gran potencial para actividades de acuicultura en la zona por su reproducción continua y altas tasas de crecimiento y productividad. Abstract in english The oyster Crassostrea rhizophorae is a bivalve of commercial interest, common in mangrove communities of eastern Venezuela. This study was conducted in order to evaluate the production of biomass of species in a natural population of Laguna Grande de Obispo, Cariaco Gulf, Venezuela. Monthly samplin [...] gs were carried out between May 2002 and May 2003 in two stations. Using a simple random sampling design, the abundance and biomass of bivalves fixed on mangrove roots Rhizophora manglae were determined, estimating the secondary production by the specific growth rate method. Mean density was 818.13ind/m² and mean biomass was 662.39g/m² of root, without sig

Antulio, Prieto; Andrés, Montes; Lilia J, Ruiz.

2008-10-08

31

VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 kom...

Partio, Satu

2012-01-01

32

?-Nb9VO25  

Directory of Open Access Journals (Sweden)

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

Rawia Nasri

2014-05-01

33

?-Nb9VO25.  

Science.gov (United States)

The title compound, nona-niobium vanadium penta-cosa-oxide, was prepared by a solid-state reaction at 1198?K. It is isotypic with Nb9AsO25, Nb9PO25 and Ta9VO25. The structure consists of NbO6 octa-hedra (one with 4/m.. and two with m.. symmetry) and VO4 tetra-hedra (-4.. symmetry) sharing corners and edges to form a three-dimensional framework. This framework can be considered as a junction between ribbons made up from NbO6 octa-hedra and chains of NbO6 octa-hedra and chains of VO4 tetra-hedra. The V site shows half-occupancy, hence one half of the VO4 tetra-hedra is unoccupied. The structural differences with ?-Nb9VO25, VOSO4, SbOPO4 and NbOPO4 oxides are discussed. PMID:24860297

Nasri, Rawia; Chérif, Saïda Fatma; Zid, Mohamed Faouzi; Driss, Ahmed

2014-05-01

34

Cambios en la biomasa de raíces y micorrizas arbusculares en cultivos itinerantes del Amazonas Venezolano / Changes in root biomass and arbuscular mycorrhizae in shifting crops of the Venezuelan Amazon / Mudanças na biomassa de raízes e micorrizas arbusculares em cultivos itinerantes do Amazonas Venezolano  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in portuguese A designação de biomassa a produção de raízes finas em plantas terrestres e a formação de associações simbióticas micorrízico arbusculares (MA) constituem adaptações de importância em condições de baixa fertilidade. Em um mosaico de agricultura itinerante, conformado por duas áreas de cultivo (parce [...] las), duas áreas de 2-4 e de 4-6 anos de abandono depois de ser cultivadas (pousios) e uma área de bosque chuvoso pouco perturbado, se compararam a biomassa de raízes finas (diâmetro Abstract in spanish La asignación de biomasa a la producción de raíces finas en plantas terrestres y la formación de asociaciones simbióticas micorrízico arbusculares (MA) constituyen de importantes adaptaciones en condiciones de baja fertilidad. En un mosaico de agricultura itinerante, conformado por dos áreas de cult [...] ivo (conucos), dos áreas de 2-4 y de 4-6 años de abandono después de ser cultivadas (barbechos) y un área de bosque lluvioso poco perturbado, se compararon la biomasa de raíces finas (diámetro Abstract in english The allocation of biomass to the production of fine roots in terrestrial plants and arbuscular mycorrhizal (AM) symbiotic partnerships are important adaptations under conditions of low fertility. In a mosaic of shifting cultivation, comprising two growing areas (conucos) and two 2-4 and 4-6 years de [...] serted areas after being cultivated (fallow), and a little disturbed rain forest area, differences in fine root biomass (diameter

Carolina, Kalinhoff; Alicia, Cáceres; Leonardo, Lugo.

2009-08-01

35

Cuantificación de ácidos grasos a partir de biomasa microalgal  

Directory of Open Access Journals (Sweden)

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

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

García Sánchez, J. L.

1993-12-01

36

La biomasa en la producción de electricidad en España  

Directory of Open Access Journals (Sweden)

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.

Espejo Marín, Cayetano

2005-06-01

37

Biomasa acústica y distribución del jurel Trachurus murphyien el Perú  

Directory of Open Access Journals (Sweden)

Full Text Available Se analizan los resultados de las evaluaciones hidroacústicas del recurso jurel Trachurus murphyi Nichols 1920 realizadas en aguas peruanas entre 1983 – 2012. Desde 1983 se incluyó al T. murphyicomo especie de estudio durante los cruceros de evaluación de recursos pelágicos ejecutados por el Instituto del Mar del Perú. Debido al énfasis en la estimación de biomasa de la anchoveta Engraulis ringens y de la sardina Sardinops sagax cuando esta última es más abundante, los cruceros se llevan a cabo durante el verano austral y las áreas de evaluación están circunscritas a las zonas más costeras hasta 100 mn, con sólo algunas exploraciones en otras estaciones y hasta 200 millas. El máximo valor de biomasa de 8.51 millones de toneladas de T. murphyien aguas peruanas estimado con las evaluaciones hidroacústicas fue encontrado durante el crucero realizado en otoño (marzo-mayo de 1983. En los años siguientes los estimados de biomasa acústica fluctuaron entre 180 mil toneladas en 1985 y otro máximo de 8.47 millones de toneladas en 1993, para luego disminuir gradualmente hasta un mínimo de 1239 t en 2010, con una ligera recuperación en los años 2011 y 2012. El área de distribución de T. murphyifue muy fluctuante en todo el periodo observado.

Marceliano Segura

2013-10-01

38

Actividad enzimática, degradación de residuos sólidos orgánicos y generación de biomasa útil del macromiceto grifola frondosa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Montoya Barreto, Sandra (2008) Actividad enzimática, degradación de residuos sólidos orgánicos y generación de biomasa útil del macromiceto grifola frondosa. Maestría thesis, Universidad Nacional de Colombia - Sede Manizales.

Montoya Barreto, Sandra

2008-01-01

39

Remoción y recuperación de cromo (III de soluciones acuosas por biomasa de sorgo  

Directory of Open Access Journals (Sweden)

Full Text Available En este trabajo se investigó la capacidad de la biomasa de ?desecho de sorgo? para remover y recuperar iones de cromo(III de soluciones acuosas, tanto en sistemas en lote como en flujo continuo. Los resultados muestran que los iones de cromo(III se unen preferentemente a la biomasa de sorgo a pH 4.5-5, después de 15 minutos de contacto, con una capacidad de saturación de aproximadamente 10 mg/g de biomasa seca. La biomasa inmovilizada fue capaz de remover y recuperar eficientemente iones de cromo(III en flujo continuo y en varios ciclos de remoción-recuperación.

I. Cano Rodr\\u00EDguez

2002-01-01

40

POTENCIALIDADES DE GENERACIÓN DE ELETRICIDAD A PARTIR DE BIOMASA  

Directory of Open Access Journals (Sweden)

Full Text Available La instalación de una destilería de etanol para la Generación de Energía Renovable Integrada a la Producción de Alimentos (GERIPA presenta muchas ventajas en comparación con las destilerías tradicionales. La biomasa constituye una de las principales fuentes de generación de energía limpia y barata, pasando de ser un subproducto a ser una salida fundamental del proceso productivo. En el trabajo se calcula la energía disponible en el bagazo y paja de caña y de sorgo, así como en el biogás obtenido, para producir vapor destinado a los procesos y a la producción de electricidad, utilizando un generador de vapor tradicional con eficiencia de 88%, y un turbogenerador de condensación y extracción con rendimiento de 70%. En particular, para el caso de una planta de este tipo productora de 125 000 L/día de etanol, la generación de electricidad a partir de la biomasa que esta industria produce, alcanza el valor 6,0 MW de potencia eléctrica a entregar al Sistema Energético Nacional. Constituye una fuente de desarrollo económico, social y estratégico, atendiendo al concepto de auto sostenibilidad dado en el Protocolo de Kyoto.

PEDRO A. RODRIGUEZ

2010-01-01

 
 
 
 
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Selective synthesis of tetragonal LaVO4 with different vanadium sources and its luminescence performance  

International Nuclear Information System (INIS)

Highlights: ? Pure tetragonal (t-) LaVO4 have been obtained with different vanadium sources. ? Different vanadium sources will bring different shapes of the obtained products. ? A common process of obtaining t-LaVO4 with any vanadium sources is proposed. ? A mechanism of selective synthesis of t-LaVO4 is put forward. ? Vanadium source will influence luminescent behavior of the obtained t-LaVO4:Eu. - Abstract: Pure tetragonal phase LaVO4 (t-LaVO4) was prepared through a simple solution method with different vanadium sources (V2O5, NH4VO3, NaVO3) in the absence of any templates or catalysts. The products were characterized by XRD, TEM, FT-IR and Raman spectroscopies. Effects of pH value, crystallization time, crystallization temperature and vanadium source on the structure and shape of LaVO4 were investigated. The results show that pure t-LaVO4 can be obtained in wide ranges of pH value and crystallization temperature with different vanadium sources as starting material. And vanadium source will affect morphology of the obtained products. Nanoparticles with a diameter of about 30 nm have been obtained. Nanorods with different sizes and aspect ratio have been produced. A process to produce t-LaVO4 was proposed and the process is thought to be feasible for any vanadium sources. A formation mechanism of t-LaVO4 was discussed. A dissoluble complex of La, V, O is presumed as a key factor for producing t-LaVO4 in this mechanism. Luminescence performances of the samples produced with different vanadium sources were also investigated.

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VoWiFi Roaming  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Freedom is human’s natural instinct, which was limited by Ethernet and Fixed Telephony Era. With the emergence of new technologies like wireless fidelity (WiFi) and voice over IP (VoIP) humans once again have freedom of movement; which at the very same time provides enough reasons to change the market dynamics of communication industry. The buzz of Voice over WiFi (VoWiFi) in recent years indicates that VoWiFi is shaping up as the next big challenge to traditional telephony, not only due to...

Muhammad Ali, Syed

2006-01-01

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Synthesis, characterization and catalytic activity of two novel cis-dioxovanadium(v) complexes: [VO2(L)] and [VO2(Hlox)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Dois novos complexos [VO2(L)] e [VO2(HLox)] foram sintetizados e caracterizados por espectroscopias no IV, UV-Vis e RMN, voltametria cíclica, análise elementar e difração de raios X. A síntese do ligante inédito H2Lox também é descrita. Os complexos 1 e 2 foram obtidos pela reação de [VO(acac)2] com [...] os respectivos ligantes HL e H2Lox. Alternativamente, 2 foi preparado a partir da reação de HL com [VO(acac)2] na presença de hidroxilamina, e através da reação de 1 com hidroxilamina. Dados cristalográficos mostram que 1 e 2 apresentam estruturas moleculares similares, onde o centro de vanádio(V) cis-dioxo encontra-se coordenado em um ambiente octaédrico distorcido formado pelos ligantes L- e HLox-, respectivamente. A atividade catalítica destes compostos foi avaliada na oxidação do cicloexano, utilizando H2O2 e t-BuOOH como oxidantes. Ambos apresentam seletividade > 70% para formação de cicloexilidroperóxido. Cálculos B3LYP/6-31G(d) foram empregados na otimização da geometria e para auxiliar na atribuição do espectro eletrônico. Abstract in english Two novel complexes, [VO2(L)] (1) and [VO2(HLox)] (2), were synthesized and characterized by IV, UV-Vis and NMR spectroscopy, cyclic voltammetry, elemental analysis and X-ray diffraction. The synthesis of a new ligand, H2Lox, is also described. Complexes 1 and 2 were obtained by the reaction of [VO( [...] acac)2] with the ligands HL and H2Lox, respectively. Alternatively, 2 was also obtained by the reaction of HL with [VO(acac)2] in the presence of hydroxylamine, and by the reaction of 1 with hydroxylamine. Crystallographic data show that complexes 1 and 2 have similar molecular structures, in which the cis-dioxovanadium(V) center is coordinated to L- or HLox-, respectively, in a distorted octahedral environment. The catalytic activity of these compounds towards cyclohexane oxidation was evaluated using H2O2 and t-BuOOH as oxidants. Both complexes presented > 70% selectivity for cyclohexylhydroperoxide formation. B3LYP/6-31G(d) calculations were used to confirm the geometry and to help assign the electronic spectra.

Natália M. L., Silva; Carlos B., Pinheiro; Eluzir P., Chacon; Jackson A. L. C., Resende; José Walkimar de M., Carneiro; Tatiana L., Fernández; Marciela, Scarpellini; Mauricio, Lanznaster.

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 i...

Ednez Romero, Anirebis Mart U.; Angel Leyva Gal\\u00E1n

2014-01-01

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 d...

Mendoza, Jorge M.; Bula, Antonio J.; Go?mez, Rafael D.; Corredor, Lesmes A.

2012-01-01

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CONTENIDO DE CARBONO Y NITRÓGENO DE LA BIOMASA MICROBIANA EN SUELOS DE LA HABANA  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Contenido de carbono y nitrógeno de la biomasa microbiana en suelos de La Habana. La presente investigación fue diseñada con el objetivo de calcular el carbono (C) y el nitrógeno (N) inmovilizado en la biomasa microbiana de cuatro suelos Ferralíticos Rojos de la Provincia de La Habana, Cuba, empleando la metodología de "fumigación extracción" en el año 2006. Se colectaron muestras de cuatro sitios (Bainoa, La Salud, Quivicán y Guanajay), los cuales mostraron diferencias en las carac...

Mez-jorrin, Lu U. Eds A. G. U. F.; Amalia Morales-Valdes; As-vega, Graciela Due U. F.; Ednez, Juana Mar U. Eda Dantin-mart U.; Vez-gonzalez, Nereida Ch U. E.; Maite Torres-Leblanch

2012-01-01

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Lo?pez Gonza?lez, Diego

2013-01-01

48

Estimación de biomasa por métodos alométricos, nutrimentos y carbono en plantaciones de palmito en Costa Rica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

El agroecosistema de palmito (Bactris gasipaes) es un sistema de producción sostenible en los trópicos húmedos. Los métodos alométricos permiten predecir la producción de biomasa en forma no destructiva en cualquier momento y a partir de este dato determinar las fases de crecimiento del cultivo, los componentes de la biomasa y los nutrimentos asociados a cada componente, así como el rendimiento económico esperado de una plantación. Los objetivos generales d...

Ares, Adri U. E. N.; Jimmy Boniche; Pablo Quesada, Jos U. E.; Russell Yost; Eloy Molina; Smyth, Thomas J.

2002-01-01

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Accessing the VO with Python  

Science.gov (United States)

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.

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

2014-05-01

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Electron Paramagnetic Resonance Studies of Cu2+ and VO2+ Spin Probes in RO-Li2O-Na2O-K2O-B2O3 (R = Zn, Mg, Sr and Ba Glass Systems  

Directory of Open Access Journals (Sweden)

Full Text Available Mixed alkali and alkaline earth oxide glasses of RO-Li2O-Na2O-K2O-B2O3(R = Zn, Mg, Sr and Ba system were studied by electron paramagnetic resonance (EPR and optical absorption spectroscopy. Cu2+ and VO2+ ions were used as the spin probes. The glasses containing 1 mole% of Cu2+ and 2mole% of VO2+ were prepared by the melt quenching method. X-ray diffraction studies of the samples did not reveal crystalline phases. EPR measurements were made at X-band frequencies with 100 kHz field modulation, at 310 K. Optical spectra were recorded in the wavelength range 300 nm - 800 nm. From the EPR spectra the spin-Hamiltonian parameters were evaluated. The spin-Hamiltonian parameter values in the case of Cu2+ indicated that the ground state of Cu2+ was orbital (2B1g and the site symmetry around Cu2+ is tetragonally distorted octahedral. The variation of gll and All with the alkaline earth oxide (RO composition was found to be non-linear which may be due to the change in the ligand field strength at the site of Cu2+ ions. From the spin-Hamiltonian parameters of VO2+, it was observed that the vanadyl ions exist as VO2+ ions in octahedral coordination with tetragonal compression and have C4V symmetry with ground state dxy. Tetragonality (?gll/?g of V4+ ion sites exhibited non-linear variation with RO content, which indicated change in the ligand field at the site of V4+. A broad optical absorption band was observed in the glass containing Cu2+ ions corresponding to the 2B1g ? 2B2g transition. From the EPR and optical data the bond parameters were evaluated. In the case of VO2+ ions, the covalency rates were estimated.

Abdul Hameed

2012-01-01

51

Integrating Existing Software Toolkits into VO System  

CERN Document Server

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 task for the VO developers. VO architecture greatly depends on Grid and Web services, consequently the general VO integration route is "Java Ready - Grid Ready - VO Ready". In the paper, we discuss the importance of VO integration for existing toolkits and discuss the possible solutions. We introduce two efforts in the field from China-VO project, "gImageMagick" and " Galactic abundance gradients statistical research under grid environment". We also discuss what additional work should be done to convert Grid service to VO s...

Cui, C; Wang, X; Sang, J; Luo, Z; Cui, Chenzhou; Zhao, Yongheng; Wang, Xiaoqian; Sang, Jian; Luo, Ze

2004-01-01

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Integrating existing software toolkits into VO system  

Science.gov (United States)

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 task for the VO developers. VO architecture greatly depends on Grid and Web services, consequently the general VO integration route is "Java Ready - Grid Ready - VO Ready". In the paper, we discuss the importance of VO integration for existing toolkits and discuss the possible solutions. We introduce two efforts in the field from China-VO project, "gImageMagick" and "Galactic abundance gradients statistical research under grid environment". We also discuss what additional work should be done to convert Grid service to VO service.

Cui, Chenzhou; Zhao, Yong-Heng; Wang, Xiaoqian; Sang, Jian; Luo, Ze

2004-09-01

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VO for Education: Archive Prototype  

Science.gov (United States)

The number of remote control telescopes dedicated to education is increasing in many countries, leading to correspondingly larger and larger amount of stored educational data that are usually available only to local observers. Here we present the project for a new infrastructure that will allow teachers using educational telescopes to archive their data and easily publish them within the Virtual Observatory (VO) avoiding the complexity of professional tools. Students and teachers anywhere will be able to access these data with obvious benefits for the realization of grander scale collaborative projects. Educational VO data will also be an important resource for teachers not having direct access to any educational telescopes. We will use the educational telescope at our observatory in Trieste as a prototype for the future VO educational data archive resource. The publishing infrastructure will include: user authentication, content and curation validation, data validation and ingestion, VO compliant resource generation. All of these parts will be performed by means of server side applications accessible through a web graphical user interface (web GUI). Apart from user registration, that will be validated by a natural person responsible for the archive (after having verified the reliability of the user and inspected one or more test files), all the subsequent steps will be automated. This means that at the very first data submission through the webGUI, a complete resource including archive and published VO service will be generated, ready to be registered to the VO. The efforts required to the registered user will consist only in describing herself/himself at registration step and submitting the data she/he selects for publishing after each observation sessions. The infrastructure will be file format independent and the underlying data model will use a minimal set of standard VO keywords, some of which will be specific for outreach and education, possibly including VO field identification (astronomy, planetary science, solar physics). The VO published resource description will be suggested such as to allow selective access to educational data by VO aware tools, differentiating them from professional data while treating them with the same procedures, protocols and tools. The whole system will be very flexible, scalable and with the objective to leave as less work as possible to humans.

Ramella, M.; Iafrate, G.; De Marco, M.; Molinaro, M.; Knapic, C.; Smareglia, R.; Cepparo, F.

2014-05-01

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VoIP security - attacks and solutions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

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VO2máx estimado e sua velocidade correspondente predizem o desempenho de corredores amadores / Estimated VO2max and its corresponding velocity predict performance of amateur runners  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Observa-se, nos últimos anos, um importante crescimento do número de praticantes de corrida com proporcional aumento da adesão destes às provas de rua. Nesta população, a identificação dos determinantes do desempenho parece ser necessária para otimização do tempo dedicado ao treinamento. O objetivo [...] do estudo foi estabelecer a associação do consumo máximo de oxigênio (VO2máx) estimado, da velocidade crítica (VC) e da velocidade do VO2máx (V VO2máx), com os desempenhos nas provas de 3,6 km em subida e 10 e 21,1 km no plano. Doze corredores amadores (9 homens) com 36 ± 5 anos de idade foram submetidos a quatro testes: 1 e 5 km de corrida, no plano; 3,6 km de corrida, com inclinação (?8%); e um teste para determinação indireta do VO2máx. A VC foi determinada através da relação linear entre a distância e o tempo de corrida dos dois primeiros testes. Os sujeitos participaram de duas provas oficiais de 10 km e 21,1 km. A V VO2máx foi estimada a partir do VO2máx, através de equações metabólicas. O VO2máx apresentou a melhor associação com o desempenho da corrida em 10 e 21,1 km no plano. Já na subida, a V VO2máx apresentou melhor associação. Considerando todas as provas, a variável com maior média associativa foi o VO2máx (0,91±0,07), seguido do V VO2máx (0,90±0,04) e VC (0,87±0,06), respectivamente. Este estudo demonstrou elevadas associações entre variáveis fisiológicas estabelecidas por métodos indiretos, de baixo investimento e alta praticidade, com o desempenho da corrida em 10 e 21,1 km, no plano, e 3,6 km, em subida. Abstract in english In recent years, there has been a substantial increase in the number of runners, with a proportional increase in their involvement in amateur street competition. Identification of the determinants of performance in this population appears necessary for optimization of time devoted to training. The o [...] bjective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max), critical velocity (CV) and VO2max velocity (V VO2max) and athletic performance in the 3.6 km (uphill) and 10 and 21.1 km (flatland) events. Twelve amateur runners (nine male), mean age 36 ± 5 years underwent five tests: 1 and 5 km race on level ground, 3.6 km race with slope (?8%), and indirect VO2max measurement. CV was determined from the linear relationship between distance and run time on the first two tests. The subjects then took part in two official 10 km and 21.1 km (half marathon) races. V VO2max was calculated from the VO2max through a metabolic equation. VO2max showed the best association with running performance in the 10 and 21.1 km events. For the uphill race, V VO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.91±0.07), followed by V VO2max (0.90±0.04) and VC (0.87±0.06). This study showed strong associations between physiological variables established by low-cost, user-friendly indirect methods and running performance in the 10 and 21.1 km (flatland) and 3.6 km (uphill) running events.

Tony Meireles, Santos; Allan Inoue, Rodrigues; Camila Coelho, Greco; Alan Lima, Marques; Bruno Souza, Terra; Bruno Ribeiro Ramalho, Oliveira.

56

???????? ?????????? ????????? ???????????? (QoS) ?? ????????? Voice Over IP (VoIP) ???? ???????????? ??????????? ??????????? ?????????  

Digital Repository Infrastructure Vision for European Research (DRIVER)

?????? ??? ???????? ???????????? ???????? ???? ? ?????? ??? ?????????? ??? ?????????? ??? ???????? ???????????? (QoS – Quality of Service) ??? ????????? VoIP ???? ??? ???????? ??????????? ??????????? ?????????.

????????, ??????

2009-01-01

57

Optimización del proceso de bioadsorción de Cr (VI) mediante biomasa Opuntia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

En este estudio se presentan las condiciones óptimas de operación para la eliminación de cromo hexavalente en disoluciones acuosas con bajas concentraciones, mediante el empleo de biomasa Opuntia protonada (ectodermis). La bioadsorción de Cr (VI) depende en gran medida del pH, consiguiéndose la mayor eliminación a pH 2. La optimización del proceso indica, que a temperatura ambiente, la dosis más efectiva de biomasa es 1 g/L y una concentración metálica inicial de 30 mg/L. Los result...

Avile?s Gonza?lez, Mari?a Dolores; Angosto, J. M.; Ferna?ndez Lo?pez, Jose? Antonio

2013-01-01

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ESTIMACIÓN DE BIOMASA Y CARBONO EN UN BOSQUE DE Abies religiosa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se generaron dos ecuaciones para determinar biomasa y carbono en Abies religiosa (H.B.K.) Schl. et Cham. Tales ecuaciones son de la forma Y = b Xk, donde Y es el contenido de biomasa o de carbono, y X el diámetro normal (DN). Para estimar los valores b y k del modelo se utilizaron datos de 26 árboles de un área en aprovechamiento forestal, con diámetro normal entre 6.5 y 79 cm del predio -El Innominado- en San Felipe Hidalgo Nanacamilpa, Tlaxcala, México. A cada árbol se le determinó l...

Hernandez, Dulce Ma Avenda U. F. O.; Miguel Acosta Mireles; Fernando Carrillo Anzures; Etchevers Barra, Jorge D.

2009-01-01

59

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish 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 cuadran [...] tes/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 se deba a que las hojas del manglar tuvieron porcentaje más alto de epífitas. Por otro lado, T. testudinum tuvo mayor biomasa que Syringodium filiforme Kütz en la laguna arrecifal. Abstract in english The biomass and productivity of a seagrass community are useful for determining the ecological status of the coast. Leaf biomass and shoot density in beds of Thalassia testudinum Banks & Sol. ex K. D. Koenig, were compared for two environments in the Mexican Caribbean coast (N= 6 quadrants/site) in [...] November 1998. Shoot and leaf biomass values were lower in the mangrove-associated meadow than in the reef lagoon meadow. This could be related to the higher percentage of epiphytes on mangrove leaves. In addition, T. testudinum had more biomass than Syringodium filiforme Kütz in the reef lagoon.

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

2000-06-01

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Rosales Loaiza Nestor Luis; Bermúdez José Luis; Moronta Reyna; Morales Ever Darío

2007-01-01

 
 
 
 
61

Performance Evaluation for VoIP on Campus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The VoIP Campus implementation is to make the existing VoIP technology become more beneficial for campus stake holder. This VoIP on Campus (VoC) technology make use of a web server, facilitating users to carry out VoIP registration, get and changing account, and also to see others who have register and active in this VoIP network. Basically, this VoC infrastructure uses asterisk as VoIP server and playVoIP as web server interface, those programs included in a server computer. Furthermore, ...

Rendy Munadi; Iman Hedi Santoso; Asep Mulyana

2013-01-01

62

Performance of VoIP on HSDPA  

DEFF Research Database (Denmark)

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.

Wang, Bang; Pedersen, Klaus I.

2005-01-01

63

Investigation of VoIP and implementation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Ede, Aghedo

2011-01-01

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VoIP Technology: Security Issues Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ap...

Lazzez, Amor

2013-01-01

65

VoIP-tuki Android-käyttöjärjestelmässä  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This bachelor’s thesis was commissioned by Neusoft Mobile Solutions Ltd. Neusoft Mobile Solutions Ltd. has a GSMA accredited RCS Neusoft Silta application which was meant to be expanded with an IP-based VoIP call support. The aim of this thesis was to explore how VoIP is supported in Android based operation systems and in which way the Neusoft Silta Android application can be expanded to support IP-based VoIP calls. During this thesis a simplified version of a VoIP application was made...

Ahvenlampi, Juha

2013-01-01

66

Investigation of the KAlO2+KOH-KVO3-K2SO4-H2O and NaAlO2+NaOH-NaVO3-Na2SO4-H2O systems at 45 deg C  

International Nuclear Information System (INIS)

Solubility of four-component system (KAlO2+KOH)-KVO3-K2SO4-H2O at 45 deg C has been studied and solubility diagram is built. The complex compoUnd prepared K2Ox2Al2O3xSO3x6H2O is very stable and exists in Al2O3 concentration limits from 1.17 to 2.07%. In a similar system with sodium salts the central part of the diagram is occupied by the complex 2.5 Na2OxAl2O3xSO3x5.5H2O and thus the system differs from potassium complex. Sodium complex is soluble in hot mineral acids, which testifies to a stronger bond of components inside potassium complex

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Hydrothermal Synthesis and Photocatalytic Properties of Cu-doped BiVO4 Microsheets  

Directory of Open Access Journals (Sweden)

Full Text Available Using Bi(NO33·5H2O, NaVO3 and Cu(NO32·3H2O as raw materials, Cu-doped BiVO4 microsheets were synthesized by ultrasonic-hydrothermal process with cetyltrimethyl ammonium bromide (CTAB as template. The as-prepared samples were investigated by XRD, XPS, SEM, HRTEM, UV-Vis and BET tests. The results reveal that uniform and well crystallized Cu/BiVO4 microsheets in monoclinic crystal structure, with length of 1.0–2.0 ?m, width of 0.5–2.0 ?m and thickness of 200–300 nm, could be obtained via an ultrasonic-hydrothermal route assisted by 2.0 g CTAB. Compared with BiVO4 particles, Cu/BiVO4 nanosheets show a little red shift in the absorption band, resulting in a narrowed band gap (<2.4 eV. For 5.0wt% Cu/ BiVO4 microsheet, its photodegradation rate constant K is5.89 ×10–2 /min and the best photocatalytic activity is found with a 100% degradation of methylene blue (MB with 10 mg/L concentration under visible-light irradiation for 60 min.

LIU Guo-Cong, JING Zhen, ZHANG Xi-Bing, LI Xian-Feng, LIU Hong

2013-03-01

68

Evaluación de los pretratamientos con ácido sulfúrico diluido y AFEX en la biomasa lignocelulósica del tipo pasto gigante “Pennisetum Sp”  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mateus Fontecha, Lady (2011) Evaluación de los pretratamientos con ácido sulfúrico diluido y AFEX en la biomasa lignocelulósica del tipo pasto gigante “Pennisetum Sp”. Maestría thesis, Universidad Nacional de Colombia..

Mateus Fontecha, Lady

2011-01-01

69

Áhættugreining fyrir VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The goal of this thesis was to perform a risk analysis on a VoIP system for service providers. Main threats of the system were analysed and subsequently each threat was briefly introduced. Assets of the system were analysed, for the risk analysis, and probability of threat and impact of threat estimated (On the scale from low-immense). Next the risk analysis was performed, in software called RM-Studio, and the results analysed. Equivalent analysis was performed for the PSTN system for comp...

Knútur Birgir Otterstedt 1984

2011-01-01

70

Biomasa fúngica y bacteriana como indicadoras del secuestro de C en suelos de sabanas sustituidos por pinares en Uverito, Venezuela  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cualquier transformación de un ecosistema natural a un sistema agrícola o forestal conduce a una modificación importante no sólo del pool del carbono total, sino también del carbono asociado con la biomasa microbiana. Su cuantificación es importante en la determinación del impacto de las prácticas agrícolas y el cambio de uso de la tierra sobre la calidad del suelo. El objetivo de este estudio fue determinar, a través del método de inhibición selectiva, la biomasa fúngica y bacte...

Magalis Zabala; Yrma Gómez

2010-01-01

71

VoIP to the Rescue  

Science.gov (United States)

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…

Milner, Jacob

2005-01-01

72

Langattomuus osana yrityksen VoIP-järjestelmää  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tämän opinnäytetyön tavoitteena on löytää sopivin ratkaisumalli, jolla siirtyminen kiinteästä VoIP:sta mobiilimpaan ympäristöön A-lehdet Oy:ssä voidaan toteuttaa. Opinnäytetyön tarkoituksena on tutkia VoIP-tekniikka yleensä sekä langattoman siirtotien tuomia haasteita tekniikalle. Tutkimusympäristönä on A-lehtikonsernin verkkoinfrastruktuuri sekä käyttäjäkunta. Työtä varten tehtiin käyttäjätutkimuksia eri käyttäjäryhmille ja näiden pohjalta tutkittiin, mis...

Lerkki, Ella

2010-01-01

73

Synthesis models in the VO framework  

CERN Document Server

The theory interest group in the International Virtual Observatory Alliance (IVOA) has the goal of ensuring that theoretical data and services are taken into account in the IVOA standards process. In this poster we present some of the efforts carried out by this group to include evolutionary synthesis models in the VO framework. In particular we present the VO tool PGos3, developed by the INAOE (Mexico) and the Spanish Virtual Observatory which includes most of public SSP models in the VO framework (e.g. VOSpec). We also describe the problems related with the inclusion of synthesis models in the VO framework and we try to encourage people to define the way in which synthesis models should be described. This issue has implications not only for the inclusion of synthesis models in the the VO framework but also for a proper usage of synthesis models.

Cerviño, M; Terlevich, R; Rodrigo-Blanco, C; Luridiana, V; López, A; Solano, E

2007-01-01

74

Viabilidad de la integración de una planta de gasificación de biomasa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

[ES] En esta Tesis Doctoral se ha presentado un nuevo modelo de gestión de subproductos del olivar (restos de poda y orujo húmedo y graso o alperujo) basado en la tecnología de gasificación de biomasa, el cual supone un cambio en relación al actual sistema en el cual los restos de poda son eliminados mediante fragmentación mecánica o quema a cielo abierto, y el orujo es trasladado hasta las extractoras de aceite de orujo u orujeras, incurriendo por ello los agricultores en sendos...

La-cal-herrera, Jose?-antonio

2013-01-01

75

Variación de la riqueza específica y producción aérea de biomasa en pastizales semiáridos  

Digital Repository Infrastructure Vision for European Research (DRIVER)

[ES]Se estudia la producción de biomasa aérea neta, la proporción de las familias botánicas en la comunidad (gramíneas, leguminosas y otras familias), la riqueza específica y la diversidad de pastizales semiáridos en zonas de dehesa del centro-oeste peninsular. Se considera la influencia del gradiente topográfico de ladera, substrato, tipo de vegetación arbórea, altitud y características edáficas. Entre las variables edáficas se consideran pH, contenido en nitrógeno, carbono, po...

Pe?rez Corona, M. E.; Va?zquez Aldana, Beatriz R.; Garci?a Ciudad, A.; Garci?a Criado, B.

1996-01-01

76

Evaluación de la Biomasa Microbiana en el Proceso de Recuperación de Suelos  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La biomasa microbiana (BM) es una fracción orgánica relativamente lábil controlada por factores ambientales y otros relacionados con la producción y el manejo. El objetivo de este trabajo fue estudiar la dinámica de la BM en suelos sometidos a una enmienda orgánica (reservas y deyecciones animales) y su posterior evolución bajo pasturas de alfalfa. Se establecieron cinco tratamientos: testigo, parcela con aportes orgánicos y tres tratamientos con pasturas base de alfalfa en diferentes...

Toniutti, M. A.; Fornasero, L. V.; Tenorio, D.; Mollo, J.

2009-01-01

77

Acumulación de biomasa y nutrimentos en plantaciones de palmito en Guápiles, Costa Rica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se cuantificó la producción de biomasa y nutrimentos en 2 plantaciones de pejibaye para palmito (Bactris gasipaes Kunth) de 4 y 8 años, mediante la estimación mensual del peso seco de palmitos cosechados y sus residuos (hojas, cáscaras, rebrotes), durante un período de 52 semanas consecutivas en Guápiles, Costa Rica. Adicionalmente, se determinó la extracción de N, P, K, Ca y Mg en todos los componentes de la planta en cada muestreo mensual. También se rea...

Eloy Molina; Alfredo Alvarado; Jimmy Boniche; Smyth, Thomas J.

2002-01-01

78

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Ednez, V. Mart U.; A. Pell\\u00F3n; Rez, E. P. U. E.; Correa, O.; Escobedo, R.; Madruga, Y.; A. O\\u00F1a; Arencibia, R.

2005-01-01

79

TERTIARY EDUCATION IN THE KNOWLEDGE-BASED SOCIETY / Terciárne vzdelávanie vo vedomostnej spolo?nosti  

Directory of Open Access Journals (Sweden)

Full Text Available The statement describes basic knowledge focused on the tertiary education in the knowledge-based society with positive and negative implications of transnational education.V príspevku sa uvádzajú základné poznatky o terciárnom vzdelávaní vo vedomostnej spolo?nosti s osobitným zrete?om na pozitívne a negatívne dôsledky transnárodného vzdelávania.

Poláková Helena

2008-03-01

80

CONTENIDO DE CARBONO Y NITRÓGENO DE LA BIOMASA MICROBIANA EN SUELOS DE LA HABANA  

Directory of Open Access Journals (Sweden)

Full Text Available Contenido de carbono y nitrógeno de la biomasa microbiana en suelos de La Habana. La presente investigación fue diseñada con el objetivo de calcular el carbono (C y el nitrógeno (N inmovilizado en la biomasa microbiana de cuatro suelos Ferralíticos Rojos de la Provincia de La Habana, Cuba, empleando la metodología de "fumigación extracción" en el año 2006. Se colectaron muestras de cuatro sitios (Bainoa, La Salud, Quivicán y Guanajay, los cuales mostraron diferencias en las características físico - químicas, incluyendo diferencias en contenido de materia orgánica entre 2,8 y 5%. La sensibilidad de las metodologías empleadas fue valorada utilizando el error estándar de las medias como parámetro estadístico. Los niveles de C inmovilizados en la biomasa microbiana en los suelos estudiados, variaron entre 289 y 425 ug/g de suelo y tuvieron una correlación altamente signifi cativa con el contenido de materia orgánica del suelo. Los contenidos de N inmovilizados variaron entre 62 y 90 ug/g de suelo y se observó también una correlación signifi cativa entre este parámetro y el contenido de nitrógeno total. El error estándar de la media para las determinaciones del C microbiano varió entre 2 y 16 y fueron ligeramente superiores a lo hallado en reportes anteriores; mientras que los errores observados en las determinaciones del N microbiano se mantuvieron entre los rangos considerados adecuados. Finalmente la metodología fue adaptada a las condiciones del laboratorio.

Lu\\u00EDs A. G\\u00F3mez-Jorrin

2012-01-01

 
 
 
 
81

Formation of solid solutions in the pseudobinary TiO-VO system  

International Nuclear Information System (INIS)

The results of the synthesis of solid solutions in the TiO-VO pseudo-binary system are presented. The boundaries of the mutual solubility of titanium and vanadium monooxides of compositions close to the stoichiometric at the synthesis temperature of 1250 deg C have been established. On the TiO and, the boundary of the solubility attains 9.6 at. %, and on the VO end, is not lower than 5.2 at. %. All the synthesized solid solutions have an imperfect NaCl type structure and can be regarded as substitutional solid solutions

82

Biomasa acumulada e indicadores de calidad nutritiva en cebadilla chaqueña (Bromus auleticus Trinius ex Nees)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish Bromus auleticus (cebadilla chaqueña) es considerada uno de los recursos forrajeros más promisorios del Cono Sur. Presenta variación entre poblaciones que ha sido determinada para diversos caracteres vegetativos, lo cual podría traducirse en diferencias de producción y calidad de forraje. El objetiv [...] o del presente estudio fue evaluar dos procedencias de cebadilla chaqueña (Argentina y Uruguay) para biomasa acumulada e indicadores de calidad nutritiva en dos períodos del año (verano-otoño y otoño-primavera). Se compararon cinco clones uruguayos (U) y cinco argentinos (A), dispuestos al azar en surcos distanciados a 1 m entre sí, con 10 plantas cada uno. Se determinó biomasa acumulada por planta (B) y calidad, midiendo Fibra Detergente Neutra (FDN), Proteína Bruta (PB) y Digestibilidad de la Materia Seca (DMS) en dos momentos del año. En general, la biomasa fue de baja calidad debido al momento en que se realizaron los cortes, lo que limita el alcance de los resultados. Sin embargo, las diferencias observadas entre los clones en este estado de desarrollo podrían indicar la existencia de variación entre genotipos de cebadilla chaqueña U y A en biomasa y calidad nutritiva. En biomasa acumulada no se observó efecto significativo de origen. En todas las variables de calidad evaluadas en verano-otoño, se encontraron diferencias significativas entre orígenes. En otoñoprimavera, las diferencias entre orígenes fueron significativas para DMS. Los clones U presentaron mayor PB, menor FDN y mayor DMS. Dentro de cada origen, los argentinos presentaron menos diferencias que los uruguayos, tanto en biomasa acumulada como en calidad. Para ninguno de los clones A o U se encontró coincidencia entre mayor biomasa y mayor calidad. Abstract in english Bromus auleticus (“chaqueña” bromegrass) may be considered as one of the most valuable forage species for the Southern Cone. This species shows variation among populations, determined in diverse vegetative characters, which could result in differences in production and forage quality. The objective [...] of this study was to evaluate two origins of Bromus auleticus (Argentina and Uruguay) for characters of biomass accumulated and quality in two periods of the year (Summer-Autumn and Autumn-Spring). Five Uruguayan (U) and Argentine (A) clones were compared, it were randomly arranged in rows spaced one meter of each other, with 10 plants each one. Biomass accumulated per plant (B) and biomass quality were determined in two times of the year measuring neutral detergent fiber (NDF), crude protein (CP) and dry mater digestibility (DMD). In general, quality of biomass was poor due to time cuttings, limiting the scope of the results. However, differences between the clones in this stage of development could be indicating the presence of variation among genotypes of “chaqueña” prairie grass U and A in biomass and nutritional quality. Significant effect of origin for B was not observed. In all biomass quality variables evaluated in Summer-Autumn, significant differences between origins were found. In Autumn-Spring, differences between origins were significant in DMD. U clones showed more CP, less NDF and higher DMD. Within each origin, A showed less differences than U both in B and quality. Concerning A or U clones, no coincidence between high biomass and high quality was found.

E.G.R, Bustamante; M.A, Ruiz; E, Morici; F.J, Babinec; A.B, Pordomingo.

2012-12-01

83

Security in VoIP  

Directory of Open Access Journals (Sweden)

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.

Floriana GEREA

2012-04-01

84

Siirtyminen perinteisestä puhelinvaihdejärjestelmästä ?VoIP-järjestelmään  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transition from a traditional telephone exchange system to a VoIP-system The subject of this thesis is a transition from a traditional telephone exchange system to a Voice ?over Internet Protocol system (VoIP). The thesis has been completed as a project for Fujitsu ?Services Oy. The baseline has been the transition of a Finnish municipality from traditional ?telephone exchange system to the VoIP system. The writer of the thesis was as in internship at ?Fujitsu productizing and tes...

Ahonen, Pasi

2009-01-01

85

Comprehensive Comparison of VoIP SIP Protocol Problems and Cisco VoIP System  

Directory of Open Access Journals (Sweden)

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

TALAL AL-KHAROBI

2012-08-01

86

Implementasi VoIP Pada PT. Bank Sumut Medan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Teknologi VoIP (Voice over Internet Protocol) diperkenalkan setelah internet mulai berkembang sekitar tahun 1995. Teknologi VoIP sangat baik untuk digunakan dikarenakan biaya penggunaan VoIP yang murah. Layanan VoIP merupakan salah satu teknologi untuk melewatkan suatu sinyal suara melalui jaringan paket Internet protocol (IP). Oleh karena itu teknologi VoIP juga dapat menggunakan teknologi komunikasi data internet, seperti VSAT (Very Small Aperture Terminal). Dengan menggunakan teknologi jar...

Alexander A. P. S

2011-01-01

87

Formation of mesoporous heterostructured BiVO?/Bi?S? hollow discoids with enhanced photoactivity.  

Science.gov (United States)

Semiconductor heterostructures are of great interest in a wide range of applications. In this work, we design and synthesize a novel heteronanostructure with controlled relative composition, i.e., BiVO4/Bi2S3 hollow discoid-like particles with mesoporous shell. The synthesis involves a facile anion exchange process by reacting pre-synthesized BiVO4 discoid-like particles with Na2S in an aqueous solution. Benefiting from the unique structural features and the formation of heterostructure, the as-prepared BiVO4/Bi2S3 hollow discoids exhibit significantly enhanced photoelectrochemical current response and photocatalytic activity for reduction of Cr(VI) under visible-light illumination. PMID:24821565

Gao, Xuehui; Wu, Hao Bin; Zheng, Lingxia; Zhong, Yijun; Hu, Yong; Lou, Xiong Wen David

2014-06-01

88

Comprehensive Comparison of VoIP SIP Protocol Problems and Cisco VoIP System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 wit...

TALAL AL-KHAROBI; Mohmmed Abduallah Al-Mehdhar

2012-01-01

89

Performance Evaluation for VoIP on Campus  

Directory of Open Access Journals (Sweden)

Full Text Available The VoIP Campus implementation is to make the existing VoIP technology become more beneficial for campus stake holder. This VoIP on Campus (VoC technology make use of a web server, facilitating users to carry out VoIP registration, get and changing account, and also to see others who have register and active in this VoIP network. Basically, this VoC infrastructure uses asterisk as VoIP server and playVoIP as web server interface, those programs included in a server computer. Furthermore, the server interconnected with several servers, such as, PBX, SMS gateway, ENUM server, softphone and smartphone. At this moment, VoC network serve locally, but next time it will be developed so that it could be served in public network, and further VoC network could be connected to VoIP Rakyat, the biggest VoIP network in Indonesia. In this research, VoC network have been tested for several QoS parameters, such as throughput, delay, jitter, packet loss, and MOS. Average value for each parameter, are : 27 kbps throughput, 20.08 ms delay, 3.54 ms jitter, 0.08% packet loss, and 3.3 MOS. Those results  indicates that VoC network have a good performance.  

Rendy Munadi

2013-09-01

90

VoIP technology comes of age.  

Science.gov (United States)

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

2008-04-01

91

Nanostructured WO3 /BiVO4 photoanodes for efficient photoelectrochemical water splitting.  

Science.gov (United States)

Nanostructured photoanodes based on well-separated and vertically oriented WO3 nanorods capped with extremely thin BiVO4 absorber layers are fabricated by the combination of Glancing Angle Deposition and normal physical sputtering techniques. The optimized WO3 -NRs/BiVO4 photoanode modified with Co-Pi oxygen evolution co-catalyst shows remarkably stable photocurrents of 3.2 and 5.1 mA/cm(2) at 1.23 V versus a reversible hydrogen electrode in a stable Na2 SO4 electrolyte under simulated solar light at the standard 1 Sun and concentrated 2 Suns illumination, respectively. The photocurrent enhancement is attributed to the faster charge separation in the electronically thin BiVO4 layer and significantly reduced charge recombination. The enhanced light trapping in the nanostructured WO3 -NRs/BiVO4 photoanode effectively increases the optical thickness of the BiVO4 layer and results in efficient absorption of the incident light. PMID:24863862

Pihosh, Yuriy; Turkevych, Ivan; Mawatari, Kazuma; Asai, Tomohiro; Hisatomi, Takashi; Uemura, Jin; Tosa, Masahiro; Shimamura, Kiyoshi; Kubota, Jun; Domen, Kazunari; Kitamori, Takehiko

2014-09-24

92

What are suspicious VoIP delays?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Mazurczyk, Wojciech; Cabaj, Krzysztof; Szczypiorski, Krzysztof

2010-01-01

93

A Comprehensive Secure VoIP Solution  

Directory of Open Access Journals (Sweden)

Full Text Available VoIP represents the future of digital voice communications and many carriers are preparing for the VoIP revolution. However, a number of outstanding issues need to be settled. The most important are security, compression, packet size optimization, quality of service and performance in heterogeneous networks. We have addressed all of these issues [2, 3, 4, 5] and here we summarize our key findings in each of these areas.

Ashraf D. Elbayoumy

2007-09-01

94

A Comprehensive Secure VoIP Solution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VoIP represents the future of digital voice communications and many carriers are preparing for the VoIP revolution. However, a number of outstanding issues need to be settled. The most important are security, compression, packet size optimization, quality of service and performance in heterogeneous networks. We have addressed all of these issues [2, 3, 4, 5] and here we summarize our key findings in each of these areas.

Elbayoumy, Ashraf D.; Simon Shepherd

2007-01-01

95

LACK - a VoIP Steganographic Method  

CERN Document Server

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

Mazurczyk, Wojciech

2008-01-01

96

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

Directory of Open Access Journals (Sweden)

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.

V. Mart\\u00EDnez

2005-01-01

97

Recuperación de la biomasa mediante la sucesión secundaria, Cordillera Central de los Andes, Colombia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish En bosques secundarios premontanos tropicales es escasa la información sobre el tiempo requerido para recuperar la biomasa aérea y subterránea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubrían estadios serales de 3 a 36 años y est [...] imamos la biomasa de las plantas y de las raíces gruesas con ecuaciones locales. Así como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. También se calculó la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa aérea viva por hectárea (Bav) y la de las raíces gruesas por hectárea (Brg). Modelamos la Bav y Brg en función de la edad mediante la ecuación de von Bertalanfy con asíntotas de 247t/ha (Bav) y 66t/ha (Brg) resultantes de la medición de 33 parcelas de 0.1ha en los bosques primarios. Con la razón Brg/Bav=f(t) estimamos 87 años para que los bosques secundarios recuperen la Bav existente en los primarios y 217 años para recuperar la Brg. La tasa máxima de crecimiento instantáneo de la Bav fue 6.95t/ha/año a los 10 años y la tasa media máxima de crecimiento 6.26t/ha/año a los 17 años. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanzó 4.57t/ha/año y la relativa 10% anual. La razón Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 años (25%), luego disminuye hasta 25 años (18%) para luego incrementar hasta 26.7 Abstract in english Biomass recovery through secondary succession in the Cordillera Central de los Andes, Colombia. Estimations on biomass recovery rates by secondary tropical forests are needed to understand the complex tropical succession, and their importance on CO2 capture, to offset the warming of the planet. We c [...] onducted the study in the Porce River Canyon between 550 and 1 700m.a.s.l. covering tropical and premontane moist belts. We established 33 temporary plots of 50mx20m in secondary forests, including fallows to succesional forests, and ranging between 3 and 36 years old; we measured the diameter at breast height (D) of all woody plants with D?5cm. In each one of these plots we established five 10mx10m subplots, in which we measured the diameter betweem 1cm?D

Jorge Ignacio, del Valle; Héctor Iván, Restrepo; Mónica María, Londoño.

1337-13-01

98

Biomasa y composición nutricional de la asociación Cenchrus ciliaris - Gliricidia sepium al establecimiento  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se asoció Cenchrus ciliaris (Cc) y Gliricidia sepium (Gs) para evaluar la producción de biomasa y la composición química de los forrajes en la fase de establecimiento, en el estado de Morelos, México, en condiciones de trópico seco. Se empleó un análisis de varianza con diseño en bloques al azar, en donde T1 fue pasto solo, T2 Cc más Gs con 5,000 plantas ha-1 y el T3 Cs más Gs con 14,285 plantas ha-1. Se midió la producción de forraje individual y asociado con materia seca (t MS/...

Valle, J. L.; Palma, J. M.; Sangines, G. L.

2004-01-01

99

Flujos de biomasa y estructura de un ecosistema de surgencia tropical en La Guajira, Caribe colombiano  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La Guajira es un ecosistema de surgencia explotado en la costa del Caribe colombiano. Con el propósito de integrar la información disponible sobre el sistema se construyó un modelo trófico de 27 grupos funcionales usando el programa Ecopath 5.0 Beta. Se obtuvo una base cuantitativa para compararlo con otros sistemas de surgencia. La Guajira presenta una biomasa total de 68 t/km²/año, la producción primaria neta del sistema es de 1 248.51 t/km²/año y las transferencias totales del sis...

Maria Isabel Criales-Hernández; Garci?a, Camilo B.; Matthias Wolff

2006-01-01

100

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Ismael Acosta; María de Guadalupe Moctezuma-Zárate; Ca?rdenas, Juan F.; Conrado Gutiérrez

2007-01-01

 
 
 
 
101

VoIP:n tietoturva ja soveltuvuus julkishallintoon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VoIP or internet calls is a modern phoning technology. With VoIP it is possible to transfer voice and video in real-time through internet. VoIP is based on common and well established IP technology, where the information travels over the net-work in the form of IP packets. VoIP is fast becoming more general in companies, in government and among consumers. The benefits of the VoIP technology are low cost and flexibility. Since the use of VoIP has became more general, its security has also bec...

Viitala, Juha

2007-01-01

102

Security in VoIP-Current Situation and Necessary Development  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays, VoIP is getting more and more popular. It helps company to reduce cost, extends service to remote area, produce more service opportunities, etc. Besides these advantages, VoIP also put forward security problems. In this paper, we introduce the popular protocols in VoIP and their security mechanisms, by introducing threats to VoIP, we point out the vulnerabilities with the security mechanisms of each VoIP protocol, and give recommendation for each VoIP protocol. In the conclusion par...

Gao, Li Li

2006-01-01

103

BIOMASA Y RENDIMIENTO DE FRIJOL CON POTENCIAL EJOTERO EN UNICULTIVO Y ASOCIADO CON GIRASOL  

Directory of Open Access Journals (Sweden)

Full Text Available El objetivo del presente estudio fue estimar la producción de biomasa, rendimiento y algunos de sus componentes de dos cultivares de frijol (Phaseolus vulgaris L. con potencial ejotero ('Acerado' y 'Criollo', en unicultivo y asociado con dos cultivares de girasol (Helianthus annuus L. ('Sunbright' y 'Victoria'. El estudio se realizó durante el ciclo primavera verano 2006 bajo condiciones de temporal en Tenancingo, Méx. Las variables evaluadas fueron: índice de área foliar (IAF, tasa de asimilación neta (TAN, biomasa total (BT, diámetro de vaina (DV, longitud de vaina (LV, número de vainas·m-2 (NV y rendimiento de vaina·m-2 (RV; las cuales fueron analizadas en arreglo factorial, bajo un diseño de bloques completos al azar con cuatro repeticiones. Para estimar el grado de asociación, entre las variables estudiadas y el rendimiento de vainas, se realizó un análisis de correlación lineal simple. En el factor cultivares se detectaron diferencias estadísticas significativas para la TAN y DV; para el factor sistemas de siembra hubo diferencias significativas para BT, DV, NV y RV. La interacción cultivares * sistema de siembra fue significativa en todas las variables, excepto en la TAN. En ese sentido, las asociaciones 'Criollo' + 'Sunbright', 'Acerado' + 'Victoria' y 'Acerado' en unicultivo, presentaron el mayor RV. Las variables IAF, BT y NV se correlacionaron positiva y significativamente con el rendimiento de vaina. Los resultados indican que 'Criollo' y 'Acerado', asociados con 'Sunbright' y 'Victoria', respectivamente, responden positivamente a la asociación, constituyendo una buena opción para los productores de la región de Tenancingo, México.

J. Gardu\\u00F1o-Gonz\\u00E1lez

2009-01-01

104

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

Directory of Open Access Journals (Sweden)

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

Jorge M Mendoza

2012-01-01

105

CONCENTRACIÓN DE CARBONO EN LA BIOMASA AÉREA DEL MATORRAL ESPINOSO TAMAULIPECO  

Directory of Open Access Journals (Sweden)

Full Text Available Se determinó la concentración de carbono por unidad de biomasa base peso seco de 10 especies del matorral espinoso tamaulipeco y para cada uno de sus componentes (tallo, ramas, ramillas, hojas y corteza. La concentración de carbono expresado como porcentaje de la biomasa, se hizo con el equipo Solids TOC Analyzer, que determina la concentración de carbono en muestras sólidas a través de combustión completa. Mediante un ANAVA no se encontraron diferencias en la concentración promedio de carbono de las especies (P>0.05; esta concentración varió de 44.25 a 47.08 % con una media general de 45.4±1.32 %; Cordia boissieri (44.25±1.52 % y Acacia farnesiana (44.52±1.37 % son las especies que resultaron con los valores de concentración de carbono menores, y Forestiera angustifolia (47.08±1.27 % con el más alto. El componente corteza de Cordia boissieri obtuvo el menor porcentaje de concentración de carbono (39.62±0.70 %, y las hojas de Acacia schaffneri el mayor (50.14±1.21 %; la interacción de ambos factores resultó significativa (P<0.0001.

Jos\\u00E9 I. Yerena-Yamallel

2011-01-01

106

Rapid microwave-assisted synthesis of phase controlled BiVO4 nanocrystals and research on photocatalytic properties under visible light irradiation  

International Nuclear Information System (INIS)

Pure tetragonal and monoclinic phases BiVO4 were prepared from aqueous Bi (NO3)3 and NaVO3 solutions by a rapid microwave-assisted method that employed accurate controlling of microwave irradiation time and power. The highly crystalline phase converted irreversibly from tetragonal to monoclinic BiVO4 with gradually elongated irradiation time gradually, which is further proved by X-ray diffraction, UV-vis and Raman measurements. These variations of phase structures led to different photocatalytic properties under visible light

107

Rapid microwave-assisted synthesis of phase controlled BiVO{sub 4} nanocrystals and research on photocatalytic properties under visible light irradiation  

Energy Technology Data Exchange (ETDEWEB)

Pure tetragonal and monoclinic phases BiVO{sub 4} were prepared from aqueous Bi (NO{sub 3}){sub 3} and NaVO{sub 3} solutions by a rapid microwave-assisted method that employed accurate controlling of microwave irradiation time and power. The highly crystalline phase converted irreversibly from tetragonal to monoclinic BiVO{sub 4} with gradually elongated irradiation time gradually, which is further proved by X-ray diffraction, UV-vis and Raman measurements. These variations of phase structures led to different photocatalytic properties under visible light.

Zhang Huiming; Liu Jingbing, E-mail: liujingbing@bjut.edu.cn; Wang Hao; Zhang Wenxiong; Yan Hui [Beijing University of Technology, College of Materials Science and Engineering (China)

2008-05-15

108

The VO2 slow component in swimming.  

Science.gov (United States)

All studies on the oxygen uptake (VO2) slow component have been carried out for the sporting disciplines of cycling or running, but never for swimming. Considering that front crawl swimming is a sport discipline that is fundamentally different from both running and cycling, the aim of this study was to verify whether this slow component also appears in swimming. Six elite pentathletes were tested in a swimming flume while front crawl swimming to exhaustion. Swimming velocity for the slow component test was determined as v50% delta = CV + [vVO2peak - CV)/2], where CV is the critical velocity and vVO2peak the lowest velocity at which peak VO2 occurred. To set the subject's CV, expressed as the slope of a straight line that describes the correlation between swimming distance and time, the record times over three swimming distances were recorded in a 50 m swimming pool. The vVO2peak was measured by means of an incremental test in the swimming flume. Gas exchange was measured by means of a telemetric metabolimeter (K4 RQ, Cosmed, Italy) that was connected to a snorkel. The slow component was found in all subjects, with a mean (SD) value of 239 (194) mlO2.min-1. Therefore, although front crawl swimming is fundamentally different from both running and cycling, it appears that it also incurs a VO2 slow component. The origin of this phenomenon, however, is even more uncertain than for the other sport disciplines. PMID:11394260

Demarie, S; Sardella, F; Billat, V; Magini, W; Faina, M

2001-01-01

109

Holistic VoIP Intrusion Detection and Prevention System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VoIP security is crucial for current and future networks and services. The rapid shift from a closed and confined telephony towards an all IP network supporting end to end VoIP services provides major challenges to the security plane. Faced with multiple attack vectors, new and comprehensive defensive security solutions for VoIP must emerge from the research community. This paper describes a multilayer intrusion detection and prevention system architecture for VoIP infrastructures. The key co...

Nassar, Mohamed; Niccolini, Saverio; State, Radu; Ewald, Thilo

2007-01-01

110

Middleware for Data Visualization in VO-enabled Data Archives  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a middleware for visualization and exploration of complex datasets in a VO framework, that performs interaction between data archives and existing VO client applications using PLASTIC. It comprises: (1) PLASTIC-enabled Java control applet, integrated into archive web-pages and interacting with VO applications; (2) cross-browser compatible JavaScript part managing PLASTIC-aware VO Clients (launch, data manipulation) by means of Java LiveConnect. This (or similar) s...

Zolotukhin, Ivan; Chilingarian, Igor

2007-01-01

111

Vertailussa VoIP- ja GSM- järjestelmä  

Digital Repository Infrastructure Vision for European Research (DRIVER)

GSM (Global System for Mobile Communications) is a cellural system which is used worldwide. Radiolinja company got the the first GSM-licence in Finland in 1990. GSM cellural is very popular communication system. Even more popular than landline net Internet and technological development and also VoIP (Voice over Internet Protocol) has evolved quickly. VoIP makes possible to send real-time voice-messaging and video over the public Internet or another network which use IP-protocol. Consumers...

Kopsala, Laura

2013-01-01

112

From VO2(B) to VO2(R): Theoretical structures of VO2 polymorphs and in situ electron microscopy  

Science.gov (United States)

The intermediate steps of the phase transition between the metastable monoclinic VO2(B) phase and the stable tetragonal rutile VO2(R) phase have been studied by in situ electron microscopy. A crystallographic interpretation based on the static concentration waves theory is proposed: as temperature increases, the long-range order in the complex monoclinic VO2(B) phase is lost and gradually a first intermediate ill crystallized phase with a drastically reduced symmetry is formed as evidenced from the diffraction patterns. Next, a new tetragonal phase is generated that corresponds to a state where some of the vanadium atoms are now in a disordered state. When annealing inside the microscope, this phase grows out into a superstructure, with coexistence of two possible orientation variants. In all these phases the VO6 octahedra remain virtually parallel, but for the final transition around 450°C into the rutile stable phase, half of the octahedra have to reorient; the transition therefore has the aspects of a reconstructive one as is evident from the in situ experiment.

Leroux, Ch.; Nihoul, G.; van Tendeloo, G.

1998-03-01

113

Estimación de la biomasa aérea de seis leguminosas leñosas del Chaco Árido (Argentina)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish La posibilidad de contar con estimaciones confiables de la biomasa aérea de la vegetación leñosa resulta imprescindible para el manejo productivo, la conservación o la restauración de los ecosistemas de bosque. Sin embargo, no siempre se dispone de técnicas relativamente sencillas y no destructivas. [...] Este trabajo presenta modelos de regresión para estimar la biomasa aérea total de seis especies arbustivas y arbóreas de la familia Fabaceae, nativas del Chaco Árido (Prosopis flexuosa, Geoffroea decorticans, Cercidium praecox, Acacia furcatispina, Mimoziganthus carinatus y Prosopis torquata). Los modelos incluyeron distintas combinaciones del diámetro a la base (DAB) y la altura de los individuos. Todos ellos predijeron aceptablemente la biomasa por especie, si bien el de regresión lineal que utiliza el DAB² como variable independiente presentó el mejor ajuste. Las especies fueron agrupadas según sus rasgos comunes en: monopódicas de madera dura, multitallares de madera extremadamente pesada, monopódica de madera excesivamente pesada y monopódica y multitallar de madera extremadamente pesada y para cada uno de los grupos se generó una ecuación. Abstract in english Reliable estimates of biomass for the vegetation of the Arid Chaco forest is critical for its management, conservation or restoration. However, simple and non destructive techniques are not largely available. This study provides regression models aimed at estimating the aerial biomass of native shru [...] b and tree species from the Arid Chaco, belonging to the Fabaceae family (Prosopis flexuosa, Geoffroea decorticans, Cercidium praecox, Acacia furcatispina, Mimoziganthus carinatus and Prosopis torquata). An additional objective was to explore the feasibility of using a single equation for several species. The wood density differed significantly between species. Linear and nonlinear regression models of aerial biomass were adjusted for species, with different combinations of base diameter (DAB) and height as independent variables. The models properly predicted the biomass by species, the most appropriate being the linear regression model using DAB² as an independent variable. To establish differences in the behavior of species and, more precisely, in the ratio between total dry weight and DAB, the slope homogeneity was analyzed using a regression model with auxiliary variables. Taking into account the results obtained and the basic wood density and morphological growth structure, four groups of species have been postulated, and it was feasible to apply a single equation per group. The proposed groups are: (1) monopodial hardwood (Geoffroea decorticans and Cercidium praecox), (2) multi-stem shrubs of extremely heavy wood (Acacia furcatispina and Mimoziganthus carinatus), (3) monopodial of very heavy wood (Prosopis flexuosa) and (4) monopodial and multi-stem of extremely heavy wood (Prosopis torquata).

María del Rosario, Iglesias; Alicia Haydée, Barchuk.

2010-04-01

114

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

Directory of Open Access Journals (Sweden)

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

Ismael Acosta

2007-01-01

115

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish 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 metal Abstract in english The 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

Ismael, Acosta; María de Guadalupe, Moctezuma-Zárate; Juan F, Cárdenas; Conrado, Gutiérrez.

116

Ferroelectric solid solutions in the Ca3(VO4)2-BiVO4 system  

International Nuclear Information System (INIS)

The existence of a Ca3(VO4)2-based Ca21-1.5xBix(VO4)14 (0 ? x 3(VO4)2 - BiVO4 system is shown. A second-order ferroelectric phase transition in the solid solution is discovered. As the bismuth concentration increases, the phase transition temperature is depressed from 1383 K (for x = 0) to 1003 K (x = 2.52) and the ionic conductivity decreases. The maximal second harmonic generation signal is observed for the x = 2 composition. The structure is solved for the x 0.66, 1.66, 2, and 2.52 phases using the Rietveld technique

117

Is VoIP Worth It?  

Science.gov (United States)

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…

Schaffhauser, Dian

2008-01-01

118

How To: Be VoIP-Savvy  

Science.gov (United States)

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…

Branzburg, Jeffrey

2005-01-01

119

VoIP in a Campus Environment  

Science.gov (United States)

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,…

Young, Dan

2005-01-01

120

VoIP-järjestelmän pilotointi tuotantoympäristössa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Opinnäytetyön tavoitteena oli suunnitella ja toteuttaa Voice over IP -järjestelmä Päijät-Hämeen koulutuskonsernin verkkoon. Tässä opinnäytetyössä keskitytään toteutetun järjestelmän ohjelmistopuoleen. VoIP-pilotista tehtiin kolme eri opinnäytetyötä, joista kaksi muuta käsittelivät järjestelmän verkkototeutusta sekä kustannuslaskelmien tekemistä ja käyttöönoton mahdollisuuksien kartoittamista. Työn tilaajana toimi Päijät-Hämeen koulutuskonserni, jonka puhelinve...

Jortikka, Mika

2007-01-01

 
 
 
 
121

¿Controla la biomasa de pastos marinos la densidad de los peracáridos (Crustacea: Peracarida) en lagunas tropicales?  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish Se analizó la variación en tiempo y espacio de los crustáceos peracáridos que habitan las praderas de Ruppia maritima del sistema lagunar de Alvarado, Veracruz, Golfo de México. El muestreo de esta asociación de crustáceos se realizó de diciembre de 1992 a noviembre de 1994. Los organismos se obtuvi [...] eron de 108 muestras recolectadas en seis sitios con R. maritima. La asociación de crustáceos incluyó 11 especies. Ocho especies en Amphipoda (Hourstonius laguna, Cerapus benthophilus, Apocorophium louisianum, Grandidierella bonnieroides, Leptocheirus rhizophorae, Gammarus mucronatus, Melita longisetosa y Haustorius sp.), una en Isopoda (Cassidinidea ovalis) y dos en Tanaidacea (Discapseudes holthuisi and Leptochelia savignyi). La taxocenosis, la densidad y la biomasa de estos organismos mostraron pulsos estacionales relacionados positivamente con la variación de la biomasa de R. maritima, la salinidad, los afluentes epicontinentales y las bocas de comunicación. Las especies C. ovalis, G. mucronatus, A. louisianum y D. holthuisi fueron componentes dominantes en la asociación de peracáridos. Abstract in english Does sea-grass biomass control the density of peracarids (Crustacea: Peracarida) in tropical lagoons? We analyzed the time-space variation of the peracarid crustaceans that inhabit seagrasses of the Alvarado Lagoon System, Veracruz, Gulf of Mexico. The organisms were collected from 108 samples in si [...] x sites with Ruppia maritima beds (December 1992 to November 1994). The assemblage was composed of 11 species. Eight species of Amphipoda (Hourstonius laguna, Cerapus benthophilus, Apocorophium louisianum, Grandidierella bonnieroides, Leptocheirus rhizophorae, Gammarus mucronatus, Melita longisetosa and Haustorius sp.), one of Isopoda (Cassidinidea ovalis) and two of Tanaidacea (Discapseudes holthuisi and Leptochelia savignyi) were identified. Taxocoenosis, density and biomass of peracarids showed seasonal pulses related to R. maritima biomass, salinity variation, epicontinental affluent and inlets. The species C. ovalis, G. mucronatus, A. louisianum and D. holthuisi were dominant. Rev. Biol. Trop. 55 (1): 43-53. Epub 2007 March. 31.

Ignacio, Winfield; Sergio, Cházaro-Olvera; Fernando, Álvarez.

2007-03-01

122

Análisis Exergético de la Gasificación de Biomasa / Exergy Analysis of Biomass Gasification  

Scientific Electronic Library Online (English)

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

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

123

¿Controla la biomasa de pastos marinos la densidad de los peracáridos (Crustacea: Peracarida en lagunas tropicales?  

Directory of Open Access Journals (Sweden)

Full Text Available Se analizó la variación en tiempo y espacio de los crustáceos peracáridos que habitan las praderas de Ruppia maritima del sistema lagunar de Alvarado, Veracruz, Golfo de México. El muestreo de esta asociación de crustáceos se realizó de diciembre de 1992 a noviembre de 1994. Los organismos se obtuvieron de 108 muestras recolectadas en seis sitios con R. maritima. La asociación de crustáceos incluyó 11 especies. Ocho especies en Amphipoda (Hourstonius laguna, Cerapus benthophilus, Apocorophium louisianum, Grandidierella bonnieroides, Leptocheirus rhizophorae, Gammarus mucronatus, Melita longisetosa y Haustorius sp., una en Isopoda (Cassidinidea ovalis y dos en Tanaidacea (Discapseudes holthuisi and Leptochelia savignyi. La taxocenosis, la densidad y la biomasa de estos organismos mostraron pulsos estacionales relacionados positivamente con la variación de la biomasa de R. maritima, la salinidad, los afluentes epicontinentales y las bocas de comunicación. Las especies C. ovalis, G. mucronatus, A. louisianum y D. holthuisi fueron componentes dominantes en la asociación de peracáridos.Does sea-grass biomass control the density of peracarids (Crustacea: Peracarida in tropical lagoons? We analyzed the time-space variation of the peracarid crustaceans that inhabit seagrasses of the Alvarado Lagoon System, Veracruz, Gulf of Mexico. The organisms were collected from 108 samples in six sites with Ruppia maritima beds (December 1992 to November 1994. The assemblage was composed of 11 species. Eight species of Amphipoda (Hourstonius laguna, Cerapus benthophilus, Apocorophium louisianum, Grandidierella bonnieroides, Leptocheirus rhizophorae, Gammarus mucronatus, Melita longisetosa and Haustorius sp., one of Isopoda (Cassidinidea ovalis and two of Tanaidacea (Discapseudes holthuisi and Leptochelia savignyi were identified. Taxocoenosis, density and biomass of peracarids showed seasonal pulses related to R. maritima biomass, salinity variation, epicontinental affluent and inlets. The species C. ovalis, G. mucronatus, A. louisianum and D. holthuisi were dominant. Rev. Biol. Trop. 55 (1: 43-53. Epub 2007 March. 31.

Ignacio Winfield

2007-03-01

124

Service Improvements for a VoIP Provider  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis project is on helping a Voice over Internet Protocol (VoIP) service provider by improving server side of Opticall AB's Dial over Data solution. Nowadays, VoIP is becoming more and more popular. People use VoIP to call their family and friends every day. It is cheap, especially when users are abroad, because that they do need to pay any roaming fee. Many companies also like their employees to use VoIP, not only because the cost of calling is cheap, but using VoIP means that the com...

Li, Zhang

2009-01-01

125

Using VoIP to compete.  

Science.gov (United States)

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

Werbach, Kevin

2005-09-01

126

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

Directory of Open Access Journals (Sweden)

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 cm y diferente ubicación radial de los substratos. Los factores que tienen mayor efecto sobre la productividad y biomasa fitoperifítica son los períodos hidrológicos, los días de colonización de los substratos y la profundidad. La productividad y biomsa fitoperifítica de los lagos está relacionada con la mineralización de las aguas, el transporte de nutrientes de los afluentes, los macrófitos, el bosque inundable, la descomposición de la materia orgánica y la recirculación de nutrientes en la columna de agua.

Duque Escobar Santiago R.

2000-06-01

127

Suš?estvitel'nye s rasšireniem osnovy -ov- vo množestvennom ?isle v serbskom literaturnom jazyke  

Digital Repository Infrastructure Vision for European Research (DRIVER)

V nastojaš?ej rabote avtor sdelal popytku vyjavit', kakie suš?estvitel'nye v serbskom literaturnom jazyke rasširjajut osnovu morfemoj -ov- vo množestvennom ?isle, a takže rassmotret' vse faktory i obstojatel'stva, vlijajuš?ie na dannyj process. V rabote takže govoritsja o tom, v kakih pozicijah vystupaet morf -ov-, a v kakih - allomorf -ev-. Po analogii s suš?estvitel'nymi na ? (kotoryh v praslavjanskom jazyke bylo nemnogo) v istorii serbskogo...

Nikoli? Miroslav B.

2013-01-01

128

Slovenské parlamentné vo?by 2010: nacionálna agenda na ústupe?  

Directory of Open Access Journals (Sweden)

Full Text Available The 2010 Slovak Parliamentary Elections: National Agenda on Retreat? In the Slovak parliamentary elections of 2010, the reformist centre-right parties defeated the left-nationalist coalition government led by Robert Fico. The election results brought some other surprises – the Movement for a Democratic Slovakia and its leader, three-times Prime Minister Vladimír Me?iar, as well as the Party of Hungarian Coalition were eliminated from the national parliament. Moreover, the election outcome of the radical right-wing Slovak National Party declined significantly. On the other hand, two new parties entered parliament. All in all, the election outcomes show the weakening of the nationalist agenda and the nationalist vote. The paper examines why this has happened and raises the question of to what extent it is sustainable.

Olga Gyarfášová

2011-04-01

129

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 id...

Anna Myrna Jaguaribe de Lima; Daniele Vanusca Gomes Silva; Alexandre Oscar Soares de Souza

2005-01-01

130

Modular VO oriented Java EE service deployer  

Science.gov (United States)

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 development of the new system using Java Enterprise technologies can better benefit from existing libraries to build up the single tokens implementing the IVOA standards. Each component can be built from single standards and each deployed service (i.e. service components instantiations) can consume the other components' exposed methods and services without the need of homogenizing them in dedicated libraries. Scalability can be achieved in an easier way by deploying components or sets of services on a distributed environment and using JNDI (Java Naming and Directory Interface) and RMI (Remote Method Invocation) technologies. Single service configuration will not be significantly different from the VO-Dance solution given that Java class instantiation that benefited from Java Reflection will only be moved to Java EJB pooling (and not, e.g. embedded in bundles for subsequent deployment).

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

2014-07-01

131

Producción de enzimas celulolíticas a partir de cultivos de trichoderma sp. con biomasa lignocelulósica / production of cellulolitic enzymes using trichoderma sp. with Lignocelulosic biomass  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Suesca Díaz, Adriana (2012) Producción de enzimas celulolíticas a partir de cultivos de trichoderma sp. con biomasa lignocelulósica / production of cellulolitic enzymes using trichoderma sp. with Lignocelulosic biomass. Maestría thesis, Universidad Nacional de Colombia.

Suesca Di?az, Adriana

2012-01-01

132

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Navajas Martínez, Víctor Manuel (2011) Efecto de la fertilización sobre la producción de biomasa y la absorción de nutrientes en Brachiaria decumbens y Brachiaria híbrido Mulato. Maestría thesis, Universidad Nacional de Colombia.

Navajas Marti?nez, Vi?ctor Manuel

2011-01-01

133

Conversión de biomasa recalcitrante originada en la producción de etanol a partir de la planta de banano y su fruto en combustibles mediante procesos de pirolisis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Giraldo Rivera, Oscar Darío (2012) Conversión de biomasa recalcitrante originada en la producción de etanol a partir de la planta de banano y su fruto en combustibles mediante procesos de pirolisis. Maestría thesis, Universidad Nacional de Colombia, Sede Medellìn.

Giraldo Rivera, Oscar Dari?o

2012-01-01

134

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

La generación de ecuaciones alométricas es importante para determinar la biomasa y el carbono en las especies arbóreas. Esta información es útil en los estudios de cambio climático. En el presente estudio se generaron ecuaciones alométricas para dos especies de importancia ecológica en el bosque mesófilo de montaña: Clethra mexicana DC y Alnus arguta (Schltdl) Spach. Las ecuaciones que se determinaron son de la forma Y= bXk; donde: Y= contenido de biomasa o de carbono (kg); y X= di?...

Miguel Acosta Mireles; Fernando Carrillo Anzures; Raúl Gilberto Gómez Villegas

2011-01-01

135

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Con el objetivo de proporcionar herramientas que mejoren el diseño de los sistemas de gasificación/combustión de biomasa, y los modelos cinético-químicos de dichos procesos, se presenta un estudio de la cinética química asociada al proceso de devolatilización de biomasa mediante pruebas de termogravimetría utilizando tamaños de partícula que varían de 2 a 19 mm, y tasas de calentamiento de 10, 15 y 20 K/min. El desarrollo de este trabajo se justifica debido a que no hay resultados...

Melgar, Andr U. C. S.; DAVID BORGE; Rez, Juan F. P. U. C.

2008-01-01

136

Theoretical study of the new compound VO2 (D)  

International Nuclear Information System (INIS)

The structural feature and the electronic properties of the newly synthesized compound VO2 (D) are theoretically studied. Our calculations reveal that all of the V ions in VO2 (D) form two types of chains. One of the chains contributes to the electronic states near the Fermi level, but the other one almost does not yet. Such discrepancy is attributed to the different strength of the V-O bonds belonging to the different chains. Furthermore, it is found that one type of the V-V chains characters the antiferromagnetic feature, whereas the other one is almost non-magnetic. So, the compound VO2 (D) is of one-dimensional antiferromagnetic ordering. In addition, we propose that the structural transition from VO2 (D) to the rutile-type VO2 (R) is driven by three vibrational modes. The transition temperature is estimated to be about 600 K, being consistent with experiment. -- Highlights: ? The structure and the electronic properties of VO2 (D) are theoretically revealed. ? It is found that the compound VO2 (D) is of one-dimensional antiferromagnetic ordering. ? The transition from VO2 (D) to VO2 (R) is driven by three vibrational modes.

137

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

Science.gov (United States)

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 ?m 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.

Yamin, Tony; Havdala, Tal; Sharoni, Amos

2014-12-01

138

Simulink based VoIP Analysis  

CERN Document Server

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.

Singh, Hardeep; Mian, M

2010-01-01

139

Steganography of VoIP Streams  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper concerns 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. The first one is network steganography solution which exploits free/unused protocols' fields and is known for IP, UDP or TCP protocols but has never been applied to RTP (Real-Time Transport Protocol) and RTCP (Rea...

Mazurczyk, Wojciech; Szczypiorski, Krzysztof

2008-01-01

140

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

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo deste estudo foi verificar e quantificar a magnitude do componente lento do consumo de oxigênio (CL em crianças submetidas a exercícios de corrida em esteira rolante, com cargas constantes de intensidade acima do limiar de lactato (75%D, utilizando para isso dois modelos de análise: a modelo matemático com três termos exponenciais; e b modelo deltaVO2 6-3min. Participaram do estudo oito crianças do sexo masculino (11,92 ± 0,63 anos; 44,06 ± 13,01kg; 146,63 ± 7,25cm; e níveis de maturação sexual 1 e 2, aparentemente saudáveis, não treinadas, que realizaram em diferentes dias: 1 teste incremental na esteira rolante para a determinação do consumo de oxigênio de pico (VO2pico e do limiar de lactato (LL; e 2 dois testes de carga constante em esteira rolante durante seis minutos na intensidade de 75%delta [75%delta = LL + 0,75 x (VO2pico - LL]. Para determinação do CL utilizaram-se: a modelo matemático de três termos (Exp3; e b a diferença no VO2 entre o sexto e o terceiro minuto de exercício (deltaVO2 6-3min. O CL foi expresso em valores absolutos (ml/min e também como a contribuição percentual do CL para o aumento do VO2 no final do exercício (%CL. O CL determinado pelo modelo Exp3 (129,69 ± 75,71ml/min e 8,4 ± 2,92% foi significantemente maior do que o obtido pelo modelo deltaVO2 6-3min (68,69 ± 102,54ml/min e 3,6 ± 7,34%. Portanto, os valores de CL obtidos em crianças durante o exercício de corrida realizado no domínio pesado (75%delta são dependentes do modelo de análise (Exp3 x deltaVO2 6-3min.El objetivo de este estudio ha sido el de verificar y cuantificar la magnitud del componente lento del consumo de oxígeno (CL en niños, sometidos a ejercicios de carrera en cinta rodante, con cargas constantes de intensidad por encima del límite de lactato (75%delta, utilizando para esto dos modelos de análisis: a modelo matemático con tres términos exponenciales; y b modelo deltaVO2 6-3 min. Participaron del estudio 8 niños del sexo masculino (11,92 ± 0,63 años; 44,06 ± 13,01 kg; 146,63 ± 7,25 cm; y niveles de madurez sexual 1 y 2, aparentemente saludables, no entrenados, que realizaron en diferentes días: 1 Test incremental en la cinta rodante para determinar el consumo de oxígeno de pico (VO2pico y del límite de lactato (LL; y 2 Dos tests de carga constante en cinta rodante durante seis minutos a intensidad de 75%delta [75%delta = LL + 0,75 x (VO2pico - LL]. Para determinar el CL usamos: a modelo matemático de tres términos (Exp3; y b la diferencia en el VO2 entre el sexto y el tercer minuto de ejercicio (deltaVO2 6-3 min. El CL fue expresado en valores absolutos (ml/min y también como contribución porcentual de CL para el aumento de VO2 al final del ejercicio (%CL. El CL determinado por el modelo Exp3 (129,69 ± 75,71 ml/min y 8,4 ± 2,92% fue significativamente mayor al que fue obtenido por el modelo deltaVO2 6-3 min (68,69 ± 102,54 ml/min y 3,6 ± 7,34%. Por tanto, los valores de CL obtenidos en niños durante el ejercicio de carrera realizado en dominio pesado (75%delta son dependientes del modelo de análisis (Exp3 x deltaVO2 6-3 min.The purpose of this study was to identify and quantify the magnitude of the slow component of VO2 (SC in children during running exercise, performed at heavy intensity domain (75%delta, using two different mathematical models: a three-exponential model and; b deltaVO2 6-3 min. Eight healthy male children (11.92 ± 0.63 years; 44.06 ± 13.01 kg; 146.63 ± 7.25 cm; and sexual maturity levels 1 and 2, not trained, performed in different days the following tests: 1 incremental running treadmill test to determine the peak oxygen uptake (VO2peak and the lactate threshold (LT; and 2 two transitions from baseline to 75%delta [75%D = LT + 0.75 x (VO2 peak - LT] for six minutes on treadmill. The SC was deter mined by two models: a three-exponential model (Exp3; and b the VO2 difference between the sixth and the third exercise minute (deltaVO2 6-3min. The SC was expressed as the absolute (ml/min and percent contribution

Fabiana Andrade Machado

2006-12-01

 
 
 
 
141

What are suspicious VoIP delays?  

CERN Document Server

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...

Mazurczyk, Wojciech; Szczypiorski, Krzysztof

2010-01-01

142

PRODUCCIÓN DE BIOMASA Y EXOPOLISACÁRIDOS DE Grifóla frondosa BAJO CULTIVO SUMERGIDO UTILIZANDO FUENTES DE CARBONO NO CONVENCIONALES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Grifóla frondosa es un hongo Basidiomycete comestible y medicinal que produce polisacáridos tipo glucanos (?-1,6 y ?-1,3) con actividad antitumoral e inmunomoduladora. Para el presente trabajo, el objetivo fue evaluar la incidencia de diferentes fuentes de carbono (FC) en la producción de biomasa y exopolisacári-dos (EPS), bajo condiciones de cultivo sumergido, utilizando un diseño estadístico factorial con dos factores: fuente de carbono (FC(1-7)) y medio (MB y MS). La máxim...

Paula Zapata; Diego Rojas; Carlos Fernández; David Ramírez; Gloria Restrepo; Viviana Orjuela; Marcela Arroyave; Tatiana Gómez; Lucía Atehortüa

2007-01-01

143

Utilización del medio de cultivo UIT-A en la obtención de biomasa para la identificación bioquímica micobacteriana  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se compara el medio de cultivo sólido UIT-A con el Lowenstein Jensen, para la obtención de biomasa en el montaje del test bioquímico de identificación de micobacterias "no tuberculosas" (MNT), con el objetivo de valorar la posibilidad de utilización como medio de cultivo para el montaje y análisis de dichas pruebas bioquímicas. Los resultados obtenidos en los 2 medios de cultivo utilizados fueron iguales, por lo que se recomienda el uso del medio de cultivo UIT-A fundamentalmente para ...

Mederos Cuervo, Lilian M.; CARIDAD FERRA SALAZAR; Valdivia, Jose A.

1995-01-01

144

Efeito do tempo de intervalo da amostra ventilatória na variabilidade do consumo máximo de oxigênio (VO2 máx em jogadores de futebol profissional Effect of time intervals of ventilatory sampling in the variability of maximum oxygen uptake in professional soccer players  

Directory of Open Access Journals (Sweden)

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 The purpose of this investigation was to verify the impact of seven ventilatory time intervals on the maximum oxygen uptake (VO2 max in professional soccer players. Eighteen male soccer players aged 24.4 ± 4 (18-31, weight 72.5 ± 5.9 kg (62-83 and height 176.5 ± 7 cm (164-188 were submitted to a maximum exercise test on treadmill, using the continuous protocol. The heart rate response was recorded by means of computerized ECG with 12 leads, simultaneously. The respiratory exchange ratio, carbon dioxide production, oxygen uptake and pulmonary ventilation were calculated by means of the spirometric computerized system. The results of this study demonstrated that there was significant variability (p < 0.05 in VO2 max only when it was compared instantaneously and by breath-by-breath response, in relation to other intervals analyzed (10, 20, 30, 40, 50 and 60 seconds, respectively. In conclusion, the authors observed that VO2 max increases were proportional to those found in the ventilatory sample intervals during the progressive intensity exercise. However, the higher time interval underestimated its increase. Thus, the authors suggest that the investigator should utilize mean intervals in a range between 10 and 60 seconds, since no significant statistic difference was verified among these intervals.

Paulo Roberto Santos Silva

1999-04-01

145

EFECTO DEL VERMIABONO EN CRECIMIENTO Y ACUMULACIÓN DE BIOMASA EN Aeschynomene americana L. EN BANCOS DE MINERÍA A CIELO ABIERTO  

Directory of Open Access Journals (Sweden)

instauraron parcelas de 1 m2 a las que se les adicionó 1 kg m-2 de vermiabono (compost de lombriz Eisenia foetida y se compararon con un testigo al cual no se le aplicó vermiabono. Después de un ciclo de cultivo se observó que no existieron diferencias en la sobrevivencia de las plantas (10 y 16%, pero sí en la tasa de crecimiento, debido a que las plantas tratadas con vermiabono lograron alturas ocho veces mayores que el tratamiento testigo. Esta diferencia también se observó en la acumulación de biomasa al final del ciclo de vida de la planta (120 días, puesto que las plantas tratadas acumularon 21.7 g m-2 de materia seca; de los cuales 7 g m-2 se destinaron a la producción del fruto, en contraste con las plantas del tratamiento testigo que acumularon 1.5 g m-2 de biomasa y sólo 0.2 g m-2 se asignaron a los frutos, por lo que estas plantas no produjeron semillas. Las plantas tratadas con vermiabono formaron menos raíz respecto a la biomasa total en comparación con el tratamiento testigo, por lo cual se concluye que la aplicación de compost de lombriz promueve el desarrollo de A. americana hasta formar semillas.

Rosa de Lourdes Romo Campos

2009-01-01

146

Deployment of VoIP Technology: QoS Concerns  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, Q...

Lazzez, Amor; Slimani, Thabet

2013-01-01

147

VoIP Networks Monitoring and Intrusion Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Voice over IP (VoIP) has become a major paradigm for providing flexible telecommunication services and reducing operational costs. The large-scale deployment of VoIP has been leveraged by the high-speed broadband access to the Internet and the standardization of dedicated protocols. However, VoIP faces multiple security issues including vulnerabilities inherited from the IP layer as well as specific ones. Our objective is to design, implement and validate new models and architectures for perf...

Nassar, Mohamed

2009-01-01

148

Intrusion detection mechanisms for VoIP applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VoIP applications are emerging today as an important component in business and communication industry. In this paper, we address the intrusion detection and prevention in VoIP networks and describe how a conceptual solution based on the Bayes inference approach can be used to reinforce the existent security mechanisms. Our approach is based on network monitoring and analyzing of the VoIP-specific traffic. We give a detailed example on attack detection using the SIP signaling...

Nassar, Mohamed; State, Radu; Festor, Olivier

2006-01-01

149

Voice-over-Internet protocol (VoIP) Curriculum Module  

Science.gov (United States)

This curriculum module, created by Dr. Mona Cherri at North Lake College and published by the Convergence Technology Center, presents this module of information about Voice-over-Internet protocol (VoIP) for telecommunications technology and information systems courses. Here, Dr. Cherri has broken the material into five parts: Background Information, VoIP versus public switched telephone networks (PSTNs), VoIP Applications and Services, References, and Useful URLs.

Cherri, Mona

2008-10-27

150

Efeito do tempo de intervalo da amostra ventilatória na variabilidade do consumo máximo de oxigênio (VO2 máx) em jogadores de futebol profissional / Effect of time intervals of ventilatory sampling in the variability of maximum oxygen uptake in professional soccer players  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 Abstract in english The purpose of this investigation was to verify the impact of seven ventilatory time intervals on the maximum oxygen uptake (VO2 max) in professional soccer players. Eighteen male soccer players aged 24.4 ± 4 (18-31), weight 72.5 ± 5.9 kg (62-83) and height 176.5 ± 7 cm (164-188) were submitted to a [...] maximum exercise test on treadmill, using the continuous protocol. The heart rate response was recorded by means of computerized ECG with 12 leads, simultaneously. The respiratory exchange ratio, carbon dioxide production, oxygen uptake and pulmonary ventilation were calculated by means of the spirometric computerized system. The results of this study demonstrated that there was significant variability (p

Paulo Roberto Santos, Silva; Angela, Romano; Ana Maria, Visconti; Alberto Alves de Azevedo, Teixeira; Carla Dal Maso Nunes, Roxo; Gilberto da Silva, Machado; Luciana Collet Winther, Rebello; Jorge Mendes de, Sousa.

1999-04-01

151

Low temperature deposition of VO2 thin films  

International Nuclear Information System (INIS)

VO2 thin films have been deposited by a variety of techniques such as thermal oxidation, reactive evaporation, and magnetron or ion beam sputtering. These methods routinely require deposition temperatures in excess of 400 degree C in order to promote crystallization of the VO2 phase. We report on a technique, employing low energy ion bombardment of reactively evaporated VO2, which promotes crystallization of the VO2 phase at temperatures as low as 300 degree C. Properties of films deposited at these unusually low substrate temperatures will be discussed

152

Direct synthesis of thermochromic VO2 through hydrothermal reaction  

Science.gov (United States)

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).

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

2014-04-01

153

PyVO: Python access to the Virtual Observatory  

Science.gov (United States)

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

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

2014-02-01

154

Photoemission study of TiO2/VO2 interfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2006-01-01

155

Assessing the security of VoIP Services  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VoIP networks are in a major deployment phase and are becoming widely spread out due to their extended functionality and cost efficiency. Meanwhile, as VoIP traffic is transported over the Internet, it is the target of a range of attacks that can jeopardize its proper functionality. In this paper we describe our work in a VoIP specific security assessment framework. Such an assessment is automated with integrated discovery actions, data management and security attacks allowing to perform VoIP...

Abdelnur, Humberto; State, Radu; Chrisment, Isabelle; Popi, Cristian

2007-01-01

156

Security Research on VoIP with Watermarking  

Science.gov (United States)

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.

Hu, Dong; Lee, Ping

2008-11-01

157

Evaluation of VoIP Security for Mobile Devices  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Nakarmi, Prajwol Kumar

2011-01-01

158

VoIP eli IP-puhe : SIP-protokolla  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One of the reasons moving to the VoIP is sustenance expenses of the old telenetwork. One network is enough for VoIP and other IP-traffic (Internet). It’s also easy to develop new features and applications for VoIP. VoIP is used in free services in the Internet (Skype), in commercial use (teleoperators) and as internal communications tool within corporations and organizations. There are several kind of operators in the industry. Standardizing organizations develop protocols and standards...

Seppa?nen, Pietari

2014-01-01

159

Velocidad de acumulación de biomasa en la dosificación de la fertirrigación ecológica del tomate en organopónico  

Directory of Open Access Journals (Sweden)

Full Text Available En condiciones de organopónico, fueron determinadas las curvas de materia seca sobre biomasa aérea total, por períodos de crecimiento definidos en el cultivo de tomate Vita, tomándose como criterio para determinar la dosis más oportuna de aplicación de Fitomás E. en la fertirrigación. Se utilizaron dos tratamientos del biofertilizante y un tratamiento testigo, los cuales mostraron diferencia significativa desde los primeros períodos de crecimiento. La curva de materia seca, de mejor resultado en la dosis de fertilizante fue comparada con un modelo teórico generado para estimar la acumulación diaria de materia seca, teniendo en cuenta las proporciones referidas al período de crecimiento, además los datos observados y los estimados fueron relacionados mediante una regresión lineal cuya ecuación resultó altamente significativa (R2=0.99, P< 0.01, por lo que puede señalarse que la función logística que simula la acumulación de materia seca es válida. Fueron evaluados además, los rendimientos frescos de los frutos y algunos aspectos de la calidad interna, coincidiendo con igual tendencia a la mantenida en la materia seca foliar.

Carmen Duarte D\\u00EDaz

2009-01-01

160

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

Directory of Open Access Journals (Sweden)

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

Jos\\u00E9 C. Villar

2008-01-01

 
 
 
 
161

Analisis Kualitas Layanan Sistem Telepon VoIP Memanfaatkan Jaringan WiFi USU  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Saat ini sistem komunikasi dengan mengunakan VoIP seringkali menjadi alternatif dalam berkomunikasi. Salah satu software pilihan untuk layanan komunikasi VoIP adalah Softphone X-lite dan Softphone Zoiper. Pada Tugas Akhir ini dilakukan analisis implementasi aplikasi VoIP memanfaatkan jaringan WiFi USU. Pada penelitian ini diamati layanan VoIP menggunakan Softphone VoIP selama 4 (empat) hari untuk mengamati kualitas VoIP yang dihasilkan berupa jitter, packet loss, delay dan throughput. ...

Anwar, Hawira

2014-01-01

162

Electrochemical activation of graphite felt electrode for VO2+/VO2+ redox couple application  

International Nuclear Information System (INIS)

In this work, the electrochemical activation of graphite felt electrode for vanadium redox flow battery (VRB) was studied. Graphite felt (GF) electrode was oxidized at a range of electrochemical oxidation degrees in H2SO4 solution. The electrochemical performance of the treaded GF was discussed, and the law of the surface properties of GF which changed along with the electrochemical oxidation degree was proposed. The structure, composition, surface tension and electrochemical properties of the oxidized GF (OGF) were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurements, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The GF oxidized at 560–840 mAh g?1 exhibited the best activity toward VO2+/VO2+ redox reaction, according with the highest C-OH and COOH content (ca. 34%) on its surface. The mechanisms of VO2+/VO2+ redox reaction on OGF were also discussed. VRB single cell with pristine GF and OGF as the electrode were test at various charge–discharge current densities, respectively. The columbic efficiency (CE), voltage efficiency (VE) and energy efficiency (EE) of the cell using OGF electrode are much higher than the cell using pristine GF, suggested that the electro-oxidation method is a promising technology for the activation of GF electrode

163

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste estudo foi verificar e quantificar a magnitude do componente lento do consumo de oxigênio (CL) em crianças submetidas a exercícios de corrida em esteira rolante, com cargas constantes de intensidade acima do limiar de lactato (75%D), utilizando para isso dois modelos de análise: a) [...] modelo matemático com três termos exponenciais; e b) modelo deltaVO2 6-3min. Participaram do estudo oito crianças do sexo masculino (11,92 ± 0,63 anos; 44,06 ± 13,01kg; 146,63 ± 7,25cm; e níveis de maturação sexual 1 e 2), aparentemente saudáveis, não treinadas, que realizaram em diferentes dias: 1) teste incremental na esteira rolante para a determinação do consumo de oxigênio de pico (VO2pico) e do limiar de lactato (LL); e 2) dois testes de carga constante em esteira rolante durante seis minutos na intensidade de 75%delta [75%delta = LL + 0,75 x (VO2pico - LL)]. Para determinação do CL utilizaram-se: a) modelo matemático de três termos (Exp3); e b) a diferença no VO2 entre o sexto e o terceiro minuto de exercício (deltaVO2 6-3min). O CL foi expresso em valores absolutos (ml/min) e também como a contribuição percentual do CL para o aumento do VO2 no final do exercício (%CL). O CL determinado pelo modelo Exp3 (129,69 ± 75,71ml/min e 8,4 ± 2,92%) foi significantemente maior do que o obtido pelo modelo deltaVO2 6-3min (68,69 ± 102,54ml/min e 3,6 ± 7,34%). Portanto, os valores de CL obtidos em crianças durante o exercício de corrida realizado no domínio pesado (75%delta) são dependentes do modelo de análise (Exp3 x deltaVO2 6-3min). Abstract in spanish El objetivo de este estudio ha sido el de verificar y cuantificar la magnitud del componente lento del consumo de oxígeno (CL) en niños, sometidos a ejercicios de carrera en cinta rodante, con cargas constantes de intensidad por encima del límite de lactato (75%delta), utilizando para esto dos model [...] os de análisis: a) modelo matemático con tres términos exponenciales; y b) modelo deltaVO2 6-3 min. Participaron del estudio 8 niños del sexo masculino (11,92 ± 0,63 años; 44,06 ± 13,01 kg; 146,63 ± 7,25 cm; y niveles de madurez sexual 1 y 2), aparentemente saludables, no entrenados, que realizaron en diferentes días: 1) Test incremental en la cinta rodante para determinar el consumo de oxígeno de pico (VO2pico) y del límite de lactato (LL); y 2) Dos tests de carga constante en cinta rodante durante seis minutos a intensidad de 75%delta [75%delta = LL + 0,75 x (VO2pico - LL)]. Para determinar el CL usamos: a) modelo matemático de tres términos (Exp3); y b) la diferencia en el VO2 entre el sexto y el tercer minuto de ejercicio (deltaVO2 6-3 min). El CL fue expresado en valores absolutos (ml/min) y también como contribución porcentual de CL para el aumento de VO2 al final del ejercicio (%CL). El CL determinado por el modelo Exp3 (129,69 ± 75,71 ml/min y 8,4 ± 2,92%) fue significativamente mayor al que fue obtenido por el modelo deltaVO2 6-3 min (68,69 ± 102,54 ml/min y 3,6 ± 7,34%). Por tanto, los valores de CL obtenidos en niños durante el ejercicio de carrera realizado en dominio pesado (75%delta) son dependientes del modelo de análisis (Exp3 x deltaVO2 6-3 min). Abstract in english The purpose of this study was to identify and quantify the magnitude of the slow component of VO2 (SC) in children during running exercise, performed at heavy intensity domain (75%delta), using two different mathematical models: a) three-exponential model and; b) deltaVO2 6-3 min. Eight healthy male [...] children (11.92 ± 0.63 years; 44.06 ± 13.01 kg; 146.63 ± 7.25 cm; and sexual maturity levels 1 and 2), not trained, performed in different days the following tests: 1) incremental running treadmill test to determine the peak oxygen uptake (VO2peak) and the lactate threshold (LT); and 2) two transitions from baseline to 75%delta [75%D = LT + 0.75 x (VO2 peak - LT)] for six minutes on treadmill. The SC was deter mined by two models: a) three-exponential m

Fabiana Andrade, Machado; Luiz Guilherme Antonacci, Guglielmo; Camila Coelho, Greco; Benedito Sérgio, Denadai.

2006-12-01

164

Preparation and crystal structure of a new bismuth vanadate, Bi3.33(VO4)2O2  

International Nuclear Information System (INIS)

Graphical abstract: Crystal structure of Bi3.33(VO4)2O2. Solid lines indicate the unit cell. Highlights: ? We can prepare a new bismuth vanadate, Bi3.33(VO4)2O2 by hydrothermal reaction using a hydrated sodium bismuthate. ? We clarify that the crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO4 tetrahedra. ? This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation. -- Abstract: Single crystals of a new bismuth vanadate, Bi3.33(VO4)2O2 was prepared by hydrothermal reaction using a hydrated sodium bismuthate, NaBiO3.nH2O as one of the starting compounds. The crystal structure was determined by using single crystal X-ray diffraction data. This compound crystallizes in the triclinic space group P1-bar (no. 2) with a = 7.114(1), b = 7.844(2), c = 9.372(2) A, ? = 106.090(7), ? = 94.468(7) and ? = 112.506(8)o, Z = 2 and the final R factors are R1 = 0.052 and wR2 = 0.14 for 2085 unique reflections. The crystal structure is composed by four bismuth atoms with the coordination number of 6 or 8 and two VO4 tetrahedra, and one of four bismuth atoms is statistically distributed in the splitting sites with the distance of 0.83 A. This compound exhibited photocatalytic behavior for decomposition of phenol under visible light irradiation and its activity was less than that of monoclinic BiVO4.

165

Hydrothermal synthesis and electrochemical characterization of VO{sub 2} (B) with controlled crystal structures  

Energy Technology Data Exchange (ETDEWEB)

Three different VO{sub 2} (B) nanostructures, including urchin-like VO{sub 2} (B), VO{sub 2} (B) honeycombs and VO{sub 2} (B) nanorods have been successfully fabricated through hydrothermal process by adjusting the concentrations of the oxalic acid. The microstructure and morphology of the VO{sub 2} nanostructures were evaluated by using X-ray diffraction and scanning and transmission electron microscopies. Electrochemical properties measurements of urchin-like VO{sub 2} (B) and VO{sub 2} (B) honeycombs showed excellent cycling performance, especially the urchin-like VO{sub 2} (B) exhibited higher discharge capacity and better capacity retention.

Jiang Wentao; Ni Juan [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Yu Ke, E-mail: yk5188@263.net [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Zhu Ziqiang [Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China)

2011-02-01

166

INFLUÊNCIA DO GÊNERO NOS TESTES DE VO2MÁX E RAST EM ATLETAS DE ATLETISMO  

Directory of Open Access Journals (Sweden)

Full Text Available A manutenção de níveis ótimos de potência muscular e a recuperação rápida são imprescindíveis para o bomdesempenho no atletismo. O objetivo do estudo foi de comparar entre os gêneros a média dos escores deVO2máx e do RAST e correlacionar os níveis de VO2 máx e o índice de fadiga com os níveis de potênciamáxima e média. A amostra foi constituída de n=24 atletas com 16.3±2.51 anos, sendo n=12 do GêneroMasculino (GM e n=12 do Gênero Feminino (GF. Considerou os níveis significativos p<0,05. Foramobtidos os seguintes resultados no RAST; Potência Máxima (GM e (GF 434.6±122.7 Watts e 293.8±66.2Watts (p=0.03; Potência Média 367±101.9 Watts; 226.6±53.0 Watts (p=0.02 e na Potência Mínima302.5±80.2 Watts e 237.2±206.6 Watts (p=0.00. Nos valores relativos, (GM e (GF a Potência Máxima foide 7.05±1.70 Watts/Kg e 5.49±1.22 Watts/Kg (p=0.02; Potência Média 5.95±1.36 Watts/Kg e 4.22±0.99Watts/Kg (p=0,01; Potência Mínima 4.89±1.07 Watts/Kg e 3.06±1.27 Watts/Kg (p=0,01. No VO2máx o(GM (GF obtiveram 41.1±6.2 ml.(kg.min-¹ e 32.6±6.4 ml.(kg.min-¹ (p=0.00. Encontrou uma correlaçãono VO2máx e Potência Máxima (r= 0.6744 / p= 0.01, VO2máx e a Potência Média (r= 0.8227 / p= 0.00,Potência Máxima e o Índice de Fadiga (r= 0.7326 / p= 0.00. Conclui-se que as diferenças significativasencontradas nos valores de potências máxima, média e mínima (Watts (Watts/Kg, ratificam estudosanteriores. A correlação do VO2máx e a potência média, apontam para uma possível relação direta, fato que,se confirmado, pode ajudar a entender resultados de atletas de vários níveis.

Ronaldo Nascimento Maciel

2011-07-01

167

Photoemission study of TiO2/VO2 interfaces  

CERN Document Server

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 both TiO$_2$ and SrTiO$_3$ are band insulators with $d^0$ electronic configurations and both VO$_2$ and LaTiO$_3$ are Mott insulators with $d^1$ electronic configurations. We discuss possible origins of this difference and suggest the importance of the polarity discontinuity of the interfaces. Stronger incoherent part was observed in r-TiO$_2$/VO$_2$ than in a-TiO$_2$/VO$_2$, suggesting Ti-V atomic diffusion due to the higher deposition temperature for r-TiO$_2$/VO$_2$.

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

2006-01-01

168

Adapting Legacy Phone Systems to VoIP  

Science.gov (United States)

Created and presented by Vincente D'Ingianni, Director of Professional Services at Binary Systems, Inc., this PowerPoint demonstration covers how to adapt a Legacy phone system to Voice-over-Internet Protocol (VoIP). In the demonstration, D'Ingianni covers VoIP gateways, Bandwidth, Softswitches, and carriers.

Dã¢ââingianni, Vincente

2008-10-27

169

Asterisk VoIP-puhelinjärjestelmät : käyttöympäristöjen vaikutus konfigurointiin  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tämä opinnäytetyö käsittelee tietoverkkoja hyödyntäviä ohjelmistopohjaisia puhelinjärjestelmiä. Järjestelmiin viitataan käsitteellä: VoIP-puhelinjärjestelmät (Voice over Internet Protocol), jossa ensimmäisellä osalla tarkoitetaan digitaalisen äänen reaaliaikaista siirtämistä IP-protokollaa tukevan verkon välityksellä. Tarkoituksena on tutkia kuinka käyttöympäristöjen vaatimukset vaikuttavat Asterisk-ohjelmistolla toteutetun VoIP-puhelinjärjestelmän konfiguroin...

Paukkunen, Niko

2010-01-01

170

VoIP makes voice heard--functionality is up.  

Science.gov (United States)

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

Wade, Phil; Wakelam, Mathew

2008-05-01

171

Flexible thermochromic window based on hybridized VO2/graphene.  

Science.gov (United States)

Large-scale integration of vanadium dioxide (VO2) on mechanically flexible substrates is critical to the realization of flexible smart window films that can respond to environmental temperatures to modulate light transmittance. Until now, the formation of highly crystalline and stoichiometric VO2 on flexible substrate has not been demonstrated due to the high-temperature condition for VO2 growth. Here, we demonstrate a VO2-based thermochromic film with unprecedented mechanical flexibility by employing graphene as a versatile platform for VO2. The graphene effectively functions as an atomically thin, flexible, yet robust support which enables the formation of stoichiometric VO2 crystals with temperature-driven phase transition characteristics. The graphene-supported VO2 was capable of being transferred to a plastic substrate, forming a new type of flexible thermochromic film. The flexible VO2 films were then integrated into the mock-up house, exhibiting its efficient operation to reduce the in-house temperature under infrared irradiation. These results provide important progress for the fabrication of flexible thermochromic films for energy-saving windows. PMID:23758656

Kim, Hyeongkeun; Kim, Yena; Kim, Keun Soo; Jeong, Hu Young; Jang, A-Rang; Han, Seung Ho; Yoon, Dae Ho; Suh, Kwang S; Shin, Hyeon Suk; Kim, TaeYoung; Yang, Woo Seok

2013-07-23

172

VO2(B) nanospheres: Hydrothermal synthesis and electrochemical properties  

International Nuclear Information System (INIS)

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.

173

Partición de biomasa aérea en procedencias de Pinus greggii plantadas en el sur de México / Aboveground biomass allocation of Pinus greggii provenances planted in southern México  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish La asignación de biomasa en los órganos del árbol puede ser influenciada por factores climáticos y edafológicos, competencia lumínica, y por diferencias genéticas de los árboles. El objetivo fue estimar los componentes de biomasa aérea en 13 procedencias mexicanas de Pinus greggii Engelm. plantadas [...] en 1997 en el sur de México. Se utilizaron datos de biomasa obtenidos en 2011 de 106 muestras aleatorias de ramas, 60 árboles medidos en pie y datos generales de la plantación establecida bajo un diseño experimental de bloques al azar. Se encontraron diferencias significativas (P ? 0.05) entre procedencias en acumulación de biomasa en acículas y madera con corteza. La mayor biomasa foliar fue para las procedencias del centro del país, El Piñón y Molango (5.1 t ha-1), mientras que la procedencia norteña, Los Lirios, acumuló la mayor cantidad de biomasa en madera con corteza (19.4 t ha-1). No hubo diferencias en biomasa de ramas cuyo promedio fue de 9.5 t ha-1, ni en la biomasa aérea total acumulada que fue de 25.6 t ha-1, en árboles de 14 años de edad para todas las procedencias. La biomasa se distribuyó 52.0, 33.6 y 14.4 % para madera con corteza, ramas y follaje, respectivamente. Abstract in english Biomass allocation on the tree may be influenced by climate, soil conditions, light competition and genetic differences among trees. Aboveg-round biomass components were estimated in 13 Mexican provenances of Pinus greggii Engelm. planted in 1997 in Southern México. Biomass data were collected in 20 [...] 11 from 106 random samples of branches and 60 standing trees. Data sampling was distributed under a randomized block design. Significant differences (P ? 0.05) among provenances in biomass accumulation of needles and wood + bark were found. The highest leaf biomass accumulation was for provenances from Central México, El Piñón y Molango (5.1 t ha-1). Among the northern provenances, Los Lirios accumulated the highest biomass in wood + bark (19.4 t ha-1). No differences among provenances were found in branch biomass, with an average of 9.5 t ha-1, and neither in total accumulated biomass which was 25.6 t ha-1, for 14 year-old trees. Total biomass was distributed 52.0, 33.6 and 14.4 % for wood + bark, branches and leaves, respectively.

Daniel E., Villegas-Jiménez; Gerardo, Rodríguez-Ortiz; Vicente A., Velasco-Velasco; Judith, Ruiz-Luna; José C., Carrillo-Rodríguez; Susana E., Ramírez-Sánchez.

2013-12-01

174

Flujos de biomasa y estructura de un ecosistema de surgencia tropical en La Guajira, Caribe colombiano  

Directory of Open Access Journals (Sweden)

Full Text Available La Guajira es un ecosistema de surgencia explotado en la costa del Caribe colombiano. Con el propósito de integrar la información disponible sobre el sistema se construyó un modelo trófico de 27 grupos funcionales usando el programa Ecopath 5.0 Beta. Se obtuvo una base cuantitativa para compararlo con otros sistemas de surgencia. La Guajira presenta una biomasa total de 68 t/km²/año, la producción primaria neta del sistema es de 1 248.51 t/km²/año y las transferencias totales del sistema son de 3 275 t/km²/año, lo que indica un ecosistema con una surgencia moderada comparada con otros sitios. Las mayores transferencias de energía se dan del nivel trófico I-II (68.93 %, aunque existe una importante proporción de flujos al detritus (32 %. Los resultados en los atributos de madurez del sistema sugieren que La Guajira es un ecosistema inmaduro debido a que la relación P/R excede a 1 y está en desarrollo debido a la baja ascendencia (33.7 % y alta capacidad de desarrollo (66.3 % como ocurre con otras surgencias donde se presentan valores de ascendencia entre 20 % y 35 %. Aunque los datos básicos de entrada en el modelo fueron buenos, gracias a las investigaciones que se han elaborado entre 1995 y 2000, existen algunos grupos donde no se encuentra aún información adecuada; especialmente en los valores de biomasa del fitoplancton, invertebrados, bagres, peces depredadores pelágicos, así como estimaciones de producción en invertebrados, peces depredadores pelágicos y peces pequeños pelágicos. No existe una cuantificación de las poblaciones de mamíferos y aves en el área de estudio, los cuales constituyen depredadores superiores y hacen parte esencial en sistemas de surgenciaBiomass flow and structure of a tropical upwelling ecosystem in La Guajira, Colombian Caribbean. La Guajira is an exploited tropical upwelling ecosystem in the Colombian Caribbean coast. A trophic model of 27 functional groups was constructed using the ECOPATH 5.0 Beta software to integrate the available information on the ecosystem. The model allowed a comparison with other trophic flow models of upwelling ecosystems. Total system biomass (68 t/km²/year, net system production (1248.5 t/km²/year, and total system throughput (3 275 t/km²/year make La Guajira moderate when compared with other systems. The largest amount of energy throughput is achieved from trophic level I to II (68.93 %, although an important proportion of the total flow originates from detritus (32 %. The production/respiration ratio exceeds 1, suggesting that La Guajira is an immature ecosystem and is in development, as determined by its low ascendency (33.7 % and high development capacity (66.3 %, similar to other upwellings that have values of ascendency between 20 % and 35 %. Although the basic input data were good and covered 1995 to 2000, appropriate information is still not available on some trophic groups such as biomass (for phytoplankton, invertebrates, catfishes and pelagic predator fishes, secondary production data (invertebrates, pelagic predator fishes, and small pelagic fishes, and seabird and mammal populations, which are top trophic levels and an essential part of upwelling ecosystems. Rev. Biol. Trop. 54 (4: 1257-1282. Epub 2006 Dec. 15

Maria Isabel Criales-Hernández

2006-12-01

175

Flujos de biomasa y estructura de un ecosistema de surgencia tropical en La Guajira, Caribe colombiano  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish La Guajira es un ecosistema de surgencia explotado en la costa del Caribe colombiano. Con el propósito de integrar la información disponible sobre el sistema se construyó un modelo trófico de 27 grupos funcionales usando el programa Ecopath 5.0 Beta. Se obtuvo una base cuantitativa para compararlo c [...] on otros sistemas de surgencia. La Guajira presenta una biomasa total de 68 t/km²/año, la producción primaria neta del sistema es de 1 248.51 t/km²/año y las transferencias totales del sistema son de 3 275 t/km²/año, lo que indica un ecosistema con una surgencia moderada comparada con otros sitios. Las mayores transferencias de energía se dan del nivel trófico I-II (68.93 %), aunque existe una importante proporción de flujos al detritus (32 %). Los resultados en los atributos de madurez del sistema sugieren que La Guajira es un ecosistema inmaduro debido a que la relación P/R excede a 1 y está en desarrollo debido a la baja ascendencia (33.7 %) y alta capacidad de desarrollo (66.3 %) como ocurre con otras surgencias donde se presentan valores de ascendencia entre 20 % y 35 %. Aunque los datos básicos de entrada en el modelo fueron buenos, gracias a las investigaciones que se han elaborado entre 1995 y 2000, existen algunos grupos donde no se encuentra aún información adecuada; especialmente en los valores de biomasa del fitoplancton, invertebrados, bagres, peces depredadores pelágicos, así como estimaciones de producción en invertebrados, peces depredadores pelágicos y peces pequeños pelágicos. No existe una cuantificación de las poblaciones de mamíferos y aves en el área de estudio, los cuales constituyen depredadores superiores y hacen parte esencial en sistemas de surgencia Abstract in english Biomass flow and structure of a tropical upwelling ecosystem in La Guajira, Colombian Caribbean. La Guajira is an exploited tropical upwelling ecosystem in the Colombian Caribbean coast. A trophic model of 27 functional groups was constructed using the ECOPATH 5.0 Beta software to integrate the avai [...] lable information on the ecosystem. The model allowed a comparison with other trophic flow models of upwelling ecosystems. Total system biomass (68 t/km²/year), net system production (1248.5 t/km²/year), and total system throughput (3 275 t/km²/year) make La Guajira moderate when compared with other systems. The largest amount of energy throughput is achieved from trophic level I to II (68.93 %), although an important proportion of the total flow originates from detritus (32 %). The production/respiration ratio exceeds 1, suggesting that La Guajira is an immature ecosystem and is in development, as determined by its low ascendency (33.7 %) and high development capacity (66.3 %), similar to other upwellings that have values of ascendency between 20 % and 35 %. Although the basic input data were good and covered 1995 to 2000, appropriate information is still not available on some trophic groups such as biomass (for phytoplankton, invertebrates, catfishes and pelagic predator fishes), secondary production data (invertebrates, pelagic predator fishes, and small pelagic fishes), and seabird and mammal populations, which are top trophic levels and an essential part of upwelling ecosystems. Rev. Biol. Trop. 54 (4): 1257-1282. Epub 2006 Dec. 15

Maria Isabel, Criales-Hernández; Camilo, B. García; Matthias, Wolff.

1257-12-01

176

Fitoplancton de un embalse tropical hipereutrófico (Pao-Cachinche, Venezuela): abundancia, biomasa y producción primaria  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in portuguese A abundância, biomassa e produção primária do fitoplâncton foram estimadas em duas localidades do lago da represa Pao-Cachinche (Venezuela). O lago recebe tributários com altas concentrações de nutrientes, provenientes de águas domésticas sem tratamento prévio e de granjas avícolas e suínas que o ro [...] deiam. As médias de abundância e biomassa fitoplanctônicas foram 86,1·10(9) células·m-2 e 92,1mg chl-a·m-2, respectivamente. A proporção de cianobactérias foi superior ao 75% do fitoplâncton total. A produção primária bruta variou entre 456 e 6.816 mg C·m-2·d-1, a qual pode ser considerada elevada. O lago da represa pode ser considerado hipereutrófico, devido a suas altas concentrações de nutrientes e a sua elevada produtividade biológica. A entrada de nutrientes, o auto-bloqueio de luz das algas, o lavado de células e o tratamento com agentes químicos foram os responsáveis das variações do fitoplâncton neste lagos. Abstract in spanish La abundancia, biomasa y producción primaria del fitoplancton fueron estimadas en dos localidades del embalse Pao-Cachinche (Venezuela). El embalse recibe tributarios con altas concentraciones de nutrientes, provenientes de aguas domésticas sin tratamiento previo y de granjas avícolas y porcinas que [...] lo rodean. Los promedios de abundancia y biomasa fitoplanctónicas fueron 86,1·10(9) células·m-2 y 92,1mg chl-a·m-2, respectivamente. La proporción de cianobacterias fue superior al 75% del fitoplancton total. La producción primaria bruta varió entre 456 y 6816mg C·m-2·d-1, la cual puede ser considerada elevada. El embalse puede ser considerado hipereutrófico, debido a sus altas concentraciones de nutrientes y a su elevada productividad biológica. La entrada de nutrientes, el autosombreo de las algas, el lavado de células y el tratamiento con agentes químicos fueron los responsables de las variaciones del fitoplancton en este embalse. Abstract in english Phytoplankton abundance, biomass and primary production were estimated at two localities in the Pao-Cachinche reservoir (Venezuela). The reservoir receives tributaries with large amounts of nutrients from wastewater and from neighboring pig and poultry farms. Mean phytoplankton abundance and biomass [...] were 86.1·10(9) cells·m-2 and 92.1mg chl-a·m-2, respectively. Cyanobacteria accounted for more than 75% of total phytoplankton. Gross primary production ranged between 456 and 6816mg C·m-2·d-1, which can be considered as high. Pao-Cachinche reservoir can be considered as hypereutrophic, due to the high level of nutrients and biological productivity. Nutrient input, algal self-shade, flushing of cells and treatment with chemical compounds were responsible for phytoplankton fluctuations in this reservoir.

Ernesto J, González; Mario, Ortaz; Carlos, Peñaherrera; María L., Matos.

2004-10-01

177

USO DE LA LEVADURA TORULA (TORULOPSIS UTILIS) EN LA OBTENCIÓN DE BIOMASA DE ARTEMIA  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Se llevaron a cabo estudios para determinar la factibiíidad del uso de la levadura torula (Torulopsis utilis), como fuente de alimento en cultivos intensivos de Artemia. Se alcanzaron rendimientos máximos de biomasa de 5.14 g/l y 8.43 mm de largo medio total en la variante de mejores resultados. Con [...] centraciones de levadura de 1 g/l/día en el período inicial de 6 días pueden considerarse adecuadas para el crecimiento de la Artemia, mientras que concentraciones de 3.5 y 7 g/l/día son excesivas. A partir del séptimo día 3 g/l/día constituye una concentración apropiada de alimento mientras que 1 g/l/día es insuficiente para obtener un crecimiento satisfactorio en esta etapa. Las ecuaciones de crecimiento para este cultivo en las condiciones descritas son las siguientes: variante de 1 g/l/día, L = -0.5214 + 0.4837 T; variante de 3 g/l/día, L = -1.1707 + 0.738 T. Abstract in english Studies were carried out to determine the possibilities of use torula yeast (Torulopsis utilis), as a source of feed in intensive cultured Artemia, Maximum biomass yields of 5.14 g/l and 8.43 mm of average total length were obtained for the treatment with the best results. Yeast concentration of 1 g [...] /l/day in the initial 6 days period, can be considered adequate for Artemia growth while the concentration of 1 g/l/day is insufficient to obtain a satisfactory growth. The growth equations in the described culture conditions were as follow: treatment 1 g/l/day, L= -0.5214 + 0.4837 T; treatment 3 g/l/day, L = -1.1707 + 0.738 T.

Rafael, Tizol Correa.

1994-12-01

178

Orientated Langmuir-Blodgett assembly of VO(2) nanowires.  

Science.gov (United States)

We report Langmuir-Blodgett (LB) based assembly of vanadium dioxide (VO(2)) nanowires. VO(2) nanowires were functionalized with stearic acid (SA) and cetyltrimethylammonium bromide (CTAB) and then spread on the surface in an aqueous phase in a LB trough. Surface pressure-area (pi-A) isotherms were recorded on the LB trough and show hysteretic behavior. Scanning electron microscopy investigations of morphology and alignment of the VO(2) nanowire films transferred at different points on the pi-A curve demonstrate that with increasing surface pressure there is a transition from well-separated domains of nanowires to compact and locally ordered nanowire monolayers, while aggregates of raftlike nanowire structures remain after expansion. Interestingly, X-ray diffraction studies show that VO(2) nanowire LB films exhibit (00l) crystal plane orientation, which is attributed to preferential coordination of SA and CTAB-SA complex to (001) surface of VO(2) nanowires thereby driving this orientation. PMID:19119872

Mai, Liqiang; Gu, Yanhui; Han, Chunhua; Hu, Bin; Chen, Wen; Zhang, Pengchao; Xu, Lin; Guo, Wanli; Dai, Ying

2009-02-01

179

Enfermedad pulmonar obstructiva crónica por exposición al humo de biomasa / Chronic obstructive pulmonary disease by biomass smoke exposure  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: Spanish Abstract in spanish 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%. L [...] a 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 Abstract in english In this article, the relationship between chronic obstructive pulmonary disease (COPD) and biomass smoke will be discussed. More than half of the world population uses biomass for fuel, especially in rural areas and in developing countries where usage reaches 80%. Biomass smoke inhalation creates an [...] inflammatory chronic state, which is accompanied by metalloproteinases activation and mucociliary mobility reduction. This could explain the existing association between biomass exposure and COPD, revealed by observational and epidemiological studies from developing and developed countries. In this review, the differences between COPD caused by tobacco and biomass were explored. It was found that despite the pathophysiological differences, most of the clinical characteristics, quality of life and mortality were similar. In the last ten years there have been interventions to reduce the biomass smoke exposure by using improved stoves and cleaner fuels. However, these strategies have not yet been successful due to inability to reduce contamination levels to those recommended by the World Health Organization as well as due to the lack of use. Therefore, there is an urgent need for carefully conducted, randomized field trials to determine the actual range of potentially reachable contamination reductions, the probability of use and the long term benefits of reducing the global burden of COPD

Matías, Lopez; Nicole, Mongilardi; William, Checkley.

2014-03-01

180

Enfermedad pulmonar obstructiva crónica por exposición al humo de biomasa / Chronic obstructive pulmonary disease by biomass smoke exposure  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish 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%. L [...] a 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 Abstract in english In this article, the relationship between chronic obstructive pulmonary disease (COPD) and biomass smoke will be discussed. More than half of the world population uses biomass for fuel, especially in rural areas and in developing countries where usage reaches 80%. Biomass smoke inhalation creates an [...] inflammatory chronic state, which is accompanied by metalloproteinases activation and mucociliary mobility reduction. This could explain the existing association between biomass exposure and COPD, revealed by observational and epidemiological studies from developing and developed countries. In this review, the differences between COPD caused by tobacco and biomass were explored. It was found that despite the pathophysiological differences, most of the clinical characteristics, quality of life and mortality were similar. In the last ten years there have been interventions to reduce the biomass smoke exposure by using improved stoves and cleaner fuels. However, these strategies have not yet been successful due to inability to reduce contamination levels to those recommended by the World Health Organization as well as due to the lack of use. Therefore, there is an urgent need for carefully conducted, randomized field trials to determine the actual range of potentially reachable contamination reductions, the probability of use and the long term benefits of reducing the global burden of COPD

Matías, Lopez; Nicole, Mongilardi; William, Checkley.

2014-01-01

 
 
 
 
181

Biomasa fúngica y bacteriana como indicadoras del secuestro de C en suelos de sabanas sustituidos por pinares en Uverito, Venezuela  

Directory of Open Access Journals (Sweden)

Full Text Available Cualquier transformación de un ecosistema natural a un sistema agrícola o forestal conduce a una modificación importante no sólo del pool del carbono total, sino también del carbono asociado con la biomasa microbiana. Su cuantificación es importante en la determinación del impacto de las prácticas agrícolas y el cambio de uso de la tierra sobre la calidad del suelo. El objetivo de este estudio fue determinar, a través del método de inhibición selectiva, la biomasa fúngica y bacteriana y la relación (H:B en suelos de sabana nativa sustituidos por pinares (Pinus caribaea var. hondurensis, para establecer si éstos parámetros son indicadores sensibles de cambios en el contenido de carbono en suelos de Uverito, Venezuela. La relación de aditividad del inhibidor (RAI y la inhibición total por efecto combinado del inhibidor (ITC se llevaron a cabo para determinar, si los inhibidores microbianos tuvieron actividad sobre otros organismos para los cuales éstos no estaban destinados. La cuantificación de la biomasa fúngica y bacteriana se llevó a cabo mediante el uso de la cycloheximida como inhibidor fúngico, y la estreptomicina y el cloranfenicol como inhibidores bacterianos. Esta investigación evidencia que este cambio de uso de la tierra ejerció un efecto significativo sobre la biomasa microbiana del suelo, y muestra que en el sistema de pinares existe una dominancia del componente fúngico, en contraste con la sabana nativa, en la cual domina la biomasa bacteriana. La sustitución de la sabana nativa por plantaciones de pino en Uverito, promueve un mayor secuestro del carbono en el suelo. Los valores de la relación de aditividad del inhibidor (RAI tanto para la sabana nativa como para el sistema de pinares, resultaron ambos >1.0. La inhibición total combinada (ITC resultó menor en el sistema de pinares; a partir de lo cual, es posible inferir que una elevada proporción de la biomasa microbiana fue afectada por la combinación de los inhibidores.Fungal and bacterial biomass as indicators of soil C sequestration in savannas soils substituted by pine plantations. A transformation of any natural ecosystem to an agricultural or forest system leads to an important soil modification, not only in the total carbon pool, but also in the carbon associated to the microbial biomass. This way, carbon quantification on soil quality is important for the determination of impacts of agricultural practices and land use changes. The aim of this study was to the determine, through the selective inhibition technique, the fungal and bacterial biomass, and fungal-to-bacterial ratio (F:B in pine plantations (Pinus caribaea var. hondurensis, to establish if these parameters are sensible indicators of changes in the carbon content in Uverito soils (Venezuela. Furthermore, the inhibitor additivity ratio (IAR and total combined inhibition (TCI were carried out to determine if the antibiotics caused non-target inhibition. The quantification of fungal and bacterial biomass was carried out by using of cyloheximide as fungal inhibitor, and streptomycin and chloranphenicol as specific bacterial inhibitors. This research evidences that this land use change exerted a significant effect on soil microbial biomass, and shows that in pine plantations there is a dominance of the fungal component, in contrast to the native savanna, in which the bacterial biomass dominates. The substitution of native savanna by pine plantation in Uverito promotes a major soil carbon sequestration. The values of the inhibitor additivity ratio (IAR as for native savanna as pine system, were both>1.0. The total combined inhibition (TCI was smaller in the pine systems, from which it is possible to infer that a high proportion of microbial biomass was affected by the combination of the inhibitors. Rev. Biol. Trop. 58 (3: 977-989. Epub 2010 September 01.

Magalis Zabala

2010-09-01

182

Biomasa fúngica y bacteriana como indicadoras del secuestro de C en suelos de sabanas sustituidos por pinares en Uverito, Venezuela  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish Cualquier transformación de un ecosistema natural a un sistema agrícola o forestal conduce a una modificación importante no sólo del pool del carbono total, sino también del carbono asociado con la biomasa microbiana. Su cuantificación es importante en la determinación del impacto de las prácticas a [...] grícolas y el cambio de uso de la tierra sobre la calidad del suelo. El objetivo de este estudio fue determinar, a través del método de inhibición selectiva, la biomasa fúngica y bacteriana y la relación (H:B) en suelos de sabana nativa sustituidos por pinares (Pinus caribaea var. hondurensis), para establecer si éstos parámetros son indicadores sensibles de cambios en el contenido de carbono en suelos de Uverito, Venezuela. La relación de aditividad del inhibidor (RAI) y la inhibición total por efecto combinado del inhibidor (ITC) se llevaron a cabo para determinar, si los inhibidores microbianos tuvieron actividad sobre otros organismos para los cuales éstos no estaban destinados. La cuantificación de la biomasa fúngica y bacteriana se llevó a cabo mediante el uso de la cycloheximida como inhibidor fúngico, y la estreptomicina y el cloranfenicol como inhibidores bacterianos. Esta investigación evidencia que este cambio de uso de la tierra ejerció un efecto significativo sobre la biomasa microbiana del suelo, y muestra que en el sistema de pinares existe una dominancia del componente fúngico, en contraste con la sabana nativa, en la cual domina la biomasa bacteriana. La sustitución de la sabana nativa por plantaciones de pino en Uverito, promueve un mayor secuestro del carbono en el suelo. Los valores de la relación de aditividad del inhibidor (RAI) tanto para la sabana nativa como para el sistema de pinares, resultaron ambos >1.0. La inhibición total combinada (ITC) resultó menor en el sistema de pinares; a partir de lo cual, es posible inferir que una elevada proporción de la biomasa microbiana fue afectada por la combinación de los inhibidores. Abstract in english Fungal and bacterial biomass as indicators of soil C sequestration in savannas soils substituted by pine plantations. A transformation of any natural ecosystem to an agricultural or forest system leads to an important soil modification, not only in the total carbon pool, but also in the carbon assoc [...] iated to the microbial biomass. This way, carbon quantification on soil quality is important for the determination of impacts of agricultural practices and land use changes. The aim of this study was to the determine, through the selective inhibition technique, the fungal and bacterial biomass, and fungal-to-bacterial ratio (F:B) in pine plantations (Pinus caribaea var. hondurensis), to establish if these parameters are sensible indicators of changes in the carbon content in Uverito soils (Venezuela). Furthermore, the inhibitor additivity ratio (IAR) and total combined inhibition (TCI) were carried out to determine if the antibiotics caused non-target inhibition. The quantification of fungal and bacterial biomass was carried out by using of cyloheximide as fungal inhibitor, and streptomycin and chloranphenicol as specific bacterial inhibitors. This research evidences that this land use change exerted a significant effect on soil microbial biomass, and shows that in pine plantations there is a dominance of the fungal component, in contrast to the native savanna, in which the bacterial biomass dominates. The substitution of native savanna by pine plantation in Uverito promotes a major soil carbon sequestration. The values of the inhibitor additivity ratio (IAR) as for native savanna as pine system, were both>1.0. The total combined inhibition (TCI) was smaller in the pine systems, from which it is possible to infer that a high proportion of microbial biomass was affected by the combination of the inhibitors. Rev. Biol. Trop. 58 (3): 977-989. Epub 2010 September 01.

Magalis, Zabala; Yrma, Gómez.

2010-09-01

183

COMPETENCIA POR SUSTRATO DURANTE EL DESARROLLO DE BIOMASA SULFATORREDUCTORA A PARTIR DE UN LODO METANOGÉNICO EN UN REACTOR UASB  

Directory of Open Access Journals (Sweden)

Full Text Available En este trabajo se estudió la competencia entre microorganismos metanogénicos y sulfatorreductores utilizando un reactor anaerobio de lecho de lodo granular con flujo ascendente (UASB a escala laboratorio, el cual fue usado para el enriquecimiento de biomasa sulfatorreductora a partir de un lodo granular de origen metanogénico. El reactor se alimentó con una mezcla de etanol y acetato, la carga orgánica se incrementó de 0.5 a 2 g de demanda química de oxígeno (DQO/L-d a pH de 7.0. El consumo de DQO fue mayor a 90 % y la alcalinidad producida por la oxidación del sustrato incrementó el pH en el efluente hasta 8.0. A partir de los 50 días de operación, el reactor se alimentó con lactato y sulfato para promover la sulfatorreducción. La carga orgánica se aumentó de 1 a 3 g DQO/L-d con una relación DQO/Sulfato de 0.67 a un tiempo de retención hidráulico de un día. A los 194 días de operación del reactor el máximo consumo de DQO y sulfato obtenido fue de 94 y 22 %, respectivamente. La concentración total del sulfuro alcanzada fue de 310 mg S2-/L y la actividad sulfatorreductora de la biomasa fue de 0.29 g DQO-H2S/g SSV-d, lo que mostró el desarrollo de biomasa sulfatorreductora. La actividad metanogénica que se obtuvo fue de 0.35 g DQO-CH4/g SSV-d, estos resultados mostraron que los organismos metanogénicos no fueron desplazados por las bacterias sulfatorreductoras, coexistiendo ambos tipos de microorganismos en el lodo granular anaerobio al final de la operación del reactor.

Marisol GALLEGOS-GARC\\u00CDA

2010-01-01

184

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

Directory of Open Access Journals (Sweden)

Full Text Available Uno de los mayores problemas que enfrenta la ciudad de Puno es la presencia de la lenteja de agua (Lemna gibba en la bahía interior del Lago Titicaca, debido al proceso de eutrofización que sufre a causa del mal tratamiento de las aguas residuales de la ciudad de Puno. Muchas de las estrategias planteadas hasta ahora no han dado resultados positivos en la reducción de la biomasa de Lemna gibba, debido a que estos planes están direccionados a la exterminación de este organismo. En lugar de ello se debe pensar en la forma más sostenible de hacer uso de la lenteja. Es por eso que los objetivos fueron: (a estimar la biomasa (kg/m² de lenteja de agua de la bahía interior del lago Titicaca y, (b plantear una estrategia de manejo de la lenteja de agua de la bahía interior del lago Titicaca. El promedio de la biomasa de la lenteja de agua en la bahía interior fue de 6.94 kg/m², mientras que los promedios de pH y temperatura del agua fueron de 6.3 y 13.8°C, respectivamente. Esto prueba la eficacia de este organismo para crecer en condiciones difíciles (además hay altos niveles de N, P y metales pesados, por lo que su manejo puede ser una alternativa para disminuir el proceso de eutrofización del lago. Las estrategias de manejo de lenteja estuvieron enmarcadas dentro de un plano social, económico y ambiental, lo que permite su sostenibilidad en beneficio de la población de Puno y del ecosistema del lago Titicaca.

\\u00C1ngel Canales-Guti\\u00E9rrez

2010-01-01

185

Composición de la biomasa en una asociación de pasto señal con clitoria pastoreada a diferentes asignaciones de forraje  

Directory of Open Access Journals (Sweden)

Full Text Available La asociación forrajera gramínea-leguminosa ha mostrado respuestas favorables bajo pastoreo; sin embargo, es necesario evaluar su comportamiento en diferentes condiciones de manejo. El objetivo del estudio fue determinar la biomasa presente y su composición, en una pradera de pasto señal asociado con clitoria en trópico seco, pastoreada a asignaciones de forraje de: 2.5, 4.0, 5.5 y 7.0 kg MS por 100 kg -1 PV día -1 . La unidad experimental consistió en una pradera de 400m 2 . Se utilizaron como defoliadores, becerros en pastoreo rotacional con 3 días de ocupación y 42 de des canso, en la época de lluvias. Las variables evaluadas fueron: biomasa total y sus componentes: pasto señal, clitoria, otras especies, hoja, tallo, vaina, y material vivo y material muerto. La distribución de los tratamientos en campo fue en un diseño de bloques al a zar con cuatro repeticiones. Las alturas de gramínea y leguminosa, se modificaron por la asignación de forraje ( P <0.05. Pastorear a una asignación de 2.5 kg MS por 100 kg -1 PV d -1 , produjo más baja cantidad de biomasa ( P <0.05 antes y después del pastoreo. El pasto señal y sus componentes estructurales fueron afectados por la asignación de forraje, pero no clitoria. Una asignación de 4.0 kg MS por 100 kg -1 PV d -1 es una opción para el mejor desempeño de esta asociación, permite conservar ambos componentes en comparación con la asignación de 5.5 y 7.0 kg MS por 100 kg -1 PV d -1 ; además, aporta mayor cantidad de hoja y material vivo de señal, similar a las asignaciones mayores.

R\\u00E9gulo Jim\\u00E9nez Guill\\u00E9n

2013-01-01

186

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Rrez, U. C. Ngel Canales-guti U. E.

2010-01-01

187

Composición de la biomasa en una asociación de pasto señal con clitoria pastoreada a diferentes asignaciones de forraje  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La asociación forrajera gramínea-leguminosa ha mostrado respuestas favorables bajo pastoreo; sin embargo, es necesario evaluar su comportamiento en diferentes condiciones de manejo. El objetivo del estudio fue determinar la biomasa presente y su composición, en una pradera de pasto señal asociado con clitoria en trópico seco, pastoreada a asignaciones de forraje de: 2.5, 4.0, 5.5 y 7.0 kg MS por 100 kg -1 PV día -1 . La unidad experimental consistió en una pradera de 400m 2 . Se utiliz...

R\\u00E9gulo Jim\\u00E9nez Guill\\u00E9n; Raymundo Quero Carrillo, Adri U. E. N.; Rez, Jorge P. U. E. Rez P. U. E.; Ndez, Pedro Arturo Mart U. Ednez Hern U. E.; Ndez Garay, Alfonso Hern U. E.; Jorge Leonardo Tovar Salinas; Claudia Isabel Hidalgo Moreno; Ndez, Sa U. Fal Rojas Hern U. E.

2013-01-01

188

Reinvestigation of the synthesis of LiFeVO4  

International Nuclear Information System (INIS)

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 ? = 110.489o) and ?-Fe2O3 (R-3c, a = 5.035 A, c = 13.75 A).

189

Lessons learnt in building VO resources: binding together several VO standards into an operational service  

CERN Document Server

The International Virtual Observatory Alliance (IVOA) developed numerous interoperability standards during the last several years. Most of them are quite simple to implement from the technical point of view and even contain "SIMPLE" in the title. Does it mean that it is also simple to build a working VO resource using those standards? Yes and no. "Yes" because the standards are indeed simple, and "no" because usually one needs to implement a lot more than it was thought in the beginning of the project so the time management of the team becomes difficult. In our presentation we will start with a basic case of a simple spectral data collection. Then we will describe several examples of small" technologically advanced VO resources built in CDS and VO-Paris and will show that many standards are hidden from managers' eyes at the initial stage of the project development. The projects will be: (1) the GalMer database providing access to the results of numerical simulations of galaxy interactions; (2) the full spectr...

Chilingarian, Igor; Louys, Mireille; Sidaner, Pierre Le

2011-01-01

190

VoIP emergency calling foundations and practice  

CERN Document Server

This book provides a comprehensive view of the emerging standards for VoIP emergency calling from an International perspective In this book, the authors provide a treatment of the VoIP emergency calling process that is both comprehensive, looking at all aspects of emergency calling, and practical, providing technical details on how such functions can be implemented. In addition, the authors describe the standardization efforts of the Internet Engineering Task Force who are currently working to improve the situation for VoIP emergency calls. The book provides an overview of emergency c

Wolf, Karl Heinz

2010-01-01

191

VoIP Malware: Attack Tool & Attack Scenarios  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Nassar, Mohamed; State, Radu; Festor, Olivier

2009-01-01

192

Analysis of data communications security for VoIP protocols  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Boongerd, Sanhawad; Lindstein, Fredrik

2012-01-01

193

GIPSY 3D: Analysis, Visualization and VO Tools for Datacubes  

Science.gov (United States)

The scientific goals of the AMIGA project are based on the analysis of a significant amount of spectroscopic 3D data. In order to perform this work we present an initiative to develop a new VO compliant package, including present core applications and tasks offered by the Groningen Image Processing System (GIPSY), and new ones based on use cases elaborated in collaboration with advanced users. One of the main goals is to provide local interoperability between GIPSY and other VO software. The connectivity with the Virtual Observatory environment will provide general access to 3D data VO archives and services, maximizing the potential for scientific discovery.

Ruíz, J. E.; Santander-Vela, J. D.; Espigares, V.; Verdes-Montenegro, L.; van der Hulst, J. M.

2009-09-01

194

GIPSY 3D: Analysis, visualization and VO-Tools  

Science.gov (United States)

The scientific goals of the AMIGA project are based on the analysis of a significant amount of spectroscopic 3D data. In order to perform this work we present an initiative to develop a new VO compliant package, including present core applications and tasks offered by the Groningen Image Processing System (GIPSY), and new ones based on use cases elaborated in collaboration with advanced users. One of the main goals is to provide local interoperability between GIPSY (visualization and data analysis) and other VO software. The connectivity with the Virtual Observatory environment will provide general access to 3D data VO archives and services, maximizing the potential for scientific discovery.

Ruíz, J. E.; Santander-Vela, J. D.; Espigares, V.; Verdes-Montenegro, L.; van der Hulst, J. M.

2009-07-01

195

Gipsy 3D: Analysis, Visualization and Vo-Tools  

CERN Document Server

The scientific goals of the AMIGA project are based on the analysis of a significant amount of spectroscopic 3D data. In order to perform this work we present an initiative to develop a new VO compliant package, including present core applications and tasks offered by the Groningen Image Processing System (GIPSY), and new ones based on use cases elaborated in collaboration with ad- vanced users. One of the main goals is to provide local interoperability between GIPSY (visualization and data analysis) and other VO software. The connectivity with the Virtual Observatory environment will provide general access to 3D data VO archives and services, maximizing the potential for scientific discovery.

Ruiz, J E; Espigares, V; Verdes-Montenegro, L; Van der Hulst, J M

2009-01-01

196

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

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

Muñoz V. Rosa Elvira

2005-03-01

197

Efecto del brasinoesteroide y densidad de población en la acumulación de biomasa y rendimiento de ayocote (Phaseolus coccineus L.  

Directory of Open Access Journals (Sweden)

Full Text Available Se estudió el efecto del regulador de crecimiento brasinoesteroide en la acumulación de materia seca y en el rendimiento de grano de ayocote (Phaseolus coccineus L. variedad Blanco Tlaxcala. La siembra se realizó el 3 de mayo del 2000 bajo condiciones de temporal en Tetelco, Tláhuac, D. F., México. Las densidades de siembra estudiadas fueron 60, 75, 90 105 y 120 mil plantas por hectárea. Se aplicaron 40 mg·ha-1 del brasinoesteroide (solución cuya concentración fue 1 mg·ml-1 en tres partes: 10 mg·ha-1 a los 30 días después de la siembra (dds, 10 mg·ha-1 a los 60 dds y 20 mg·ha-1 90 dds. El brasinoesteroide incrementó la biomasa total y por órganos en la mayoría de las densidades en estudio. En densidades de 105 y 120 mil plantas por hectárea el incremento de biomasa total se triplicó en comparación con las demás densidades. El brasinoesteroide incrementó el rendimiento en un 68 % en la densidad de 90 mil plantas por hectárea

M. L. P. Vargas-V\\u00E1zquez

2005-01-01

198

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

Directory of Open Access Journals (Sweden)

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

M. Garc\\u00EDa-Ulloa

2006-01-01

199

Density functional theory study of rutile VO2 surfaces  

CERN Document Server

We present the results of a density functional theory (DFT) investigation of the surfaces of rutile-like vanadium dioxide, VO2(R). We calculate the surface energies of low Miller index planes, and find that the most stable surface orientation is the (110). The equilibrium morphology of a VO2(R) particle has an acicular shape, laterally confined by (110) planes and topped by (011) planes. The redox properties of the (110) surface are investigated by calculating the relative surface free energies of the non-stoichiometric compositions as a function of oxygen chemical potential. It is found that the VO2(110) surface is oxidized with respect to the stoichiometric composition, not only at ambient conditions but also at the more reducing conditions under which bulk VO2 is stable in comparison with bulk V2O5. The adsorbed oxygen forms surface vanadyl species much more favorably than surface peroxo species.

Mellan, Thomas A

2012-01-01

200

Audio CAPTCHA for SIP-Based VoIP  

Science.gov (United States)

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.

Soupionis, Yannis; Tountas, George; Gritzalis, Dimitris

 
 
 
 
201

Disordered LiZnVO4 with a phenacite structure  

Directory of Open Access Journals (Sweden)

Full Text Available Single crystals of lithium zinc vanadate, LiZnVO4, were grown by the flux method. The structural type of this vanadate is characterized by a three-dimensional arrangement of tetrahedra sharing apices in an LiZnVO4 network. This arrangement contains three different tetrahedra, namely one [VO4] and two disordered mixed-site [Li/ZnO4] tetrahedra. The resulting lattice gives rise to hexagonal channels running along the [0001] direction. Both sites in the mixed-site [Li/ZnO4] tetrahedra are occupied by a statistical mixture of lithium and zinc with a 1:1 ratio. Therefore, LiZnVO4 appears to be the first vanadate known to crystallize with a disordered phenacite structure. Moreover, the resulting values of calculated bond valences (Li = 1.083, Zn = 2.062 and V = 5.185 tend to confirm the structural model.

Mohamed Azrour

2010-05-01

202

[Spectral analysis and band gap of RbVO3].  

Science.gov (United States)

In the present paper, RbVO3 was prepared by wet chemistry synthesis from hybrid precursor. The structure of RbVO3 was characterized by X-ray diffraction (XRD) pattern and FTIR spectra. Photoluminescent (PL) properties were investigated by UV-Vis absorption spectrum and PL spectrum. In addition, the band gap of RbVO3 was calculated by using the CASTEP code with density-functional theory (DFT) method. The results indicated that RbVO3 could emit intense green-white fluorescence with peak wavelength at 525 nm and the color coordinates was (0.318 0, 0.430 9) under UV excitation at 357 nm. It was demonstrated that the theoretical result of band gap, which is 2.67 eV, agreed well with the experiment. PMID:21322231

Li, Jie; Zhou, He-Feng; Liu, Xu-Guang; Xu, Bing-She

2010-12-01

203

Electrical and Seebeck effect measurements in Nb doped VO2  

International Nuclear Information System (INIS)

The resistance of pure and Nb doped VO2 and the Seebeck coefficient of Nb doped VO2 have been measured in the temperature range of 78 to 360 K. A simple analysis of the results shows that above 140 K and below the transition temperature the effective density of states in the conduction band of VO2 is of the order of (but larger than) one state per vanadium atom. This high effective density of states is consistent with the large effective mass (and low mobility) of electrons in this material. It is shown also that in this range, the temperature dependence of the electronic mobility in VO2 is Tsup(-?) where ? > approximately 2. Additional results are discussed in the text. (author)

204

Mathematical Representation of VoIP Connection Delay  

Directory of Open Access Journals (Sweden)

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.

M. Halas

2007-09-01

205

VoIP Operators : From a Carrier Point of View  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Voice over Internet Protocol (VoIP) is a service that has recently gained a lot of attention from the telecommunications (telecom) world since both Internet service providers (ISPs) and telecommunications operators have realized the important advantages that it can offer. Although traditional telephony is well established both in the telecom world and in our daily lives, VoIP is now competing with it by offering cost savings, simplicity, and introducing new ways of communicating. Internet ser...

Sidiropoulou, Christina

2011-01-01

206

Phase Transformation of VO2 Nanoparticles Assisted by Microwave Heating  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The microwave assisted synthesis nowadays attracts a great deal of attention. Monoclinic phase VO2 (M) was prepared from NH4VO3 and H2C2O4 · 2H2O by a rapid microwave assisted technique. The synthesis parameters, microwave irradiation time, microwave power, and calcinations temperature were systematically varied and their influences on the structure and morphology were evaluated. The microwave power level has been carried out in range 180–600?W. TEM analysis demonstrated nanosized sample...

Phatcharee Phoempoon; Lek. Sikong

2014-01-01

207

Fair Scheduling for Delay-Sensitive VoIP Traffic  

Science.gov (United States)

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.

Ahmed, Shawish; Jiang, Xiaohong; Horiguchi, Susumu

208

Audio Codecs in VoIPv6: A Performance Analysis  

Directory of Open Access Journals (Sweden)

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.

Monjur Ahmed

2014-04-01

209

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

Directory of Open Access Journals (Sweden)

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

ANDR\\u00C9S MELGAR

2008-01-01

210

Synthesis and properties of solid solutions with perovskite structure in the SrVO3-EuVO3 system  

International Nuclear Information System (INIS)

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

211

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

Directory of Open Access Journals (Sweden)

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 de la correlación entre los tests de medida directa e indirecta del VO2max, en jugadores de futsal. Fueron analizados 13 jugadores de futsal, con edades de entre 18,6 ± 1,9 años, altura igual a 177,1 ± 3,5 cm, peso de 68,5 ± 9,5 kg, índice de masa corporal (IMC de 21,7 ± 2,3 kg/m². Para la medida directa del VO2max fué utilizado el sistema ergoespirométrico computadorizado (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota para mensura indirecta del VO2max fué realizado el test de campo de 3200m. El análisis estatístico fué elaborado a través del test t-Student para las muestras pareadas y por el coeficiente de correlación de Pearson. Los valores de VO2max obtenidos en el test de medida directa no presentaron diferencias significativas en relación a la medida indirecta (62,8 ± 10,1 vs. 58,5 ± 8,5 ml/kg/min, respectivamente. Cuando correlacionamos los valores de VO2max obtenidos en ambos tests, observamos una fuerte correlación (r = 0,72. En conclusión, los tests de medida indirecta presentaron buena aceptación para los atletas de futsal, teniendo en vista la alta correlación con los tests de medida directa, el bajo costo de su aplicación y el apercibimiento de las informaciones importantes que puedem auxiliar la prescrición de el no acompañamiento del entrenamiento.The importance of the morphofunctional qualities to greater efficiency in sports has increased the interest on the improvement on the physical fitness levels of athletes. However, not many studies on the physiological variables of indoor soccer are available in the world scientific literature. Thus, the objective of this work was to verify the existence of correlation between the direct and indirect VO2max measurement tests in indoor soccer players. Thirteen indoor soccer players with age of 18.6 ± 1.9 years, height of 177.1 ± 3.5 cm, weight of 68.5 ± 9.5 kg and body mass index (BMI of 21.7 ± 2.3 kg/m² were analyzed. For the direct VO2max measurement, the computerized ergospirometric system was used (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota and for the in

Anna Myrna Jaguaribe de Lima

2005-06-01

212

PRODUCCIÓN DE BIOMASA Y EXOPOLISACÁRIDOS DE Grifóla frondosa BAJO CULTIVO SUMERGIDO UTILIZANDO FUENTES DE CARBONO NO CONVENCIONALES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Grifóla frondosa es un hongo Basidiomycete comestible y medicinal que produce polisacáridos tipo glucanos (?-1,6 y ?-1,3) con actividad antitumoral e inmunomoduladora. Para el presente trabajo, el objetivo fue evaluar la incidencia de diferentes fuentes de carbono (FC) en la producción de biomasa y [...] exopolisacári-dos (EPS), bajo condiciones de cultivo sumergido, utilizando un diseño estadístico factorial con dos factores: fuente de carbono (FC(1-7)) y medio (MB y MS). La máxima producción de biomasa micelial (21,10 ± 0,82) g/l y la máxima producción de EPS (6,53 ± 0,14) g/l se logró utilizando el medio MB suplementado con FC4. Además de lo anterior, se logró desarrollar un medio de cultivo que cumple con el objetivo de disminuir costos, de Col $18.455 a $656 por litro de medio, produciendo (14,14 ± 0,82) g/l de biomasa y (5,16 ± 0,14) g/l de EPS, utilizando el medio MS suplementando con FC4. Estos resultados abren nuevas alternativas y posibilidades en nuestro país para el desarrollo de productos a partir de esta especie con costos que estén al alcance de la población. Abstract in english Grifóla frondosa is a Basidiomycete fungus edible and medicinal, it produces polysaccharides such a glucans (?-1,6 and ?-1,3) with anti-tumor and inmuno-stimulating activity. For this work, the aim was evaluate the incidence of different carbon sources (FC) in biomass and exo-polymer (EPS) productio [...] n, under submerged culture conditions, by using a factorial statistical design with two factors: carbon source (FC(1-7)) and medium (MB and MS). The maximal yield of mycelial biomass (21,10 ± 0,82) g/l and the maximal yield in EPS (6,53 ± 0,14) g/l was achieved by using the MB medium supplemented with FC4. Besides, it was possible to develop a medium that fulfills the objective of reducing costs from $18.455 to $656 Colombian pesos for each liter of medium used, which produces (14,14 ± 0,82) g/l of biomass and (5,16 ± 0,14) g/l of EPS, using the MS medium supplemented with FC4. This result opens new alternatives and possibilities in our country for developing products of this species with cost that can be reached by population.

Paula, Zapata; Diego, Rojas; Carlos, Fernández; David, Ramírez; Gloria, Restrepo; Viviana, Orjuela; Marcela, Arroyave; Tatiana, Gómez; Lucía, Atehortüa.

2007-06-01

213

VO2 kinetics and metabolic contributions whilst swimming at 95, 100, and 105% of the velocity at VO2max.  

Science.gov (United States)

A bioenergetical analysis of swimming at intensities near competitive distances is inexistent. It was aimed to compare the transient VO2 kinetics responses and metabolic contributions whilst swimming at different velocities around VO2max. 12 trained male swimmers performed (i) an incremental protocol to determine the velocity at VO2max (vVO2max) and (ii) three square wave exercises from rest to 95, 100, and 105% of vVO2max. VO2 was directly measured using a telemetric portable gas analyser and its kinetics analysed through a double-exponential model. Metabolic contributions were assessed through the sum of three energy components. No differences were observed in the fast component response (?1--15, 18, and 16 s, A1--36, 34, and 37 mL · kg(-1) · min (-1), and Gain--32, 29, and 30 mL · min (-1) at 95, 100, and 105% of the vVO2max, resp.) but A2 was higher in 95 and 100% compared to 105% intensity (480.76 ± 247.01, 452.18 ± 217.04, and 147.04 ± 60.40 mL · min (-1), resp.). The aerobic energy contribution increased with the time sustained (83 ± 5, 74 ± 6, and 59 ± 7% for 95, 100, and 105%, resp.). The adjustment of the cardiovascular and/or pulmonary systems that determine O2 delivery and diffusion to the exercising muscles did not change with changing intensity, with the exception of VO2 slow component kinetics metabolic profiles. PMID:25045690

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

2014-01-01

214

Ternary complex formation between VO(IV)-picolinic acid or VO(IV)-6-methylpicolinic acid and small blood serum bioligands  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to assess the role of the low molecular mass bioligands of blood serum in vanadium binding, a study was made of the interactions of the complexes formed in the VO(IV)–picolinic acid and VO(IV)–6-methylpicolinic acid systems with various low molecular mass constituents of blood serum, such as oxalate, lactate, citrate and phosphate. The speciation of VO(IV) in these ternary systems and also in the binary VO(IV)–picolinic acid and VO(IV)–6-methylpicolinic acid systems was studi...

Kiss, Erzse?bet; Garribba, Eugenio; Micera, Giovanni; Kiss, Tama?s; Sakurai, Hiromu

2000-01-01

215

Neutron diffraction study of YVO3, NdVO3, and TbVO3  

CERN Document Server

The structural and magnetic properties of YVO3, NdVO3 and TbVO3 were investigated by single-crystal and powder neutron diffraction. YVO3 shows a structural phase transition at 200 K from an orthorhombic structure with the space group Pbnm to a monoclinic one with the space group P21/b. But supplementary high-resolution synchrotron diffraction experiments showed that the monoclinic distortion is extremely small. A group theoretical analysis shows that this magnetic state in the monoclinic phase is incompatible with the lattice structure, unless terms of higher than bilinear order in the spin operators are incorporated in the spin Hamiltonian. This observation is discussed in the light of recent theories invoking unusual many-body correlations between the vanadium t2g orbitals. A structural phase transition back to the orthorhombic space group Pbnm is observed upon cooling below 77 K. This transition is accompanied by a rearrangement of the magnetic structure into a mode compatible with the lattice structure. T...

Reehuis, M; Pattison, P; Ouladdiaf, B; Rheinstädter, M C; Ohl, M; Regnault, L P; Miyasaka, M; Tokura, Y; Keimer, B

2006-01-01

216

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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 obje [...] tivo 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. Abstract in spanish 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. D [...] e esta forma, el objetivo del estudio fué verificar la existencia de la correlación entre los tests de medida directa e indirecta del VO2max, en jugadores de futsal. Fueron analizados 13 jugadores de futsal, con edades de entre 18,6 ± 1,9 años, altura igual a 177,1 ± 3,5 cm, peso de 68,5 ± 9,5 kg, índice de masa corporal (IMC) de 21,7 ± 2,3 kg/m². Para la medida directa del VO2max fué utilizado el sistema ergoespirométrico computadorizado (VO-2000, Aerosport, Medgraphics, St. Paul, Minnesota) para mensura indirecta del VO2max fué realizado el test de campo de 3200m. El análisis estatístico fué elaborado a través del test t-Student para las muestras pareadas y por el coeficiente de correlación de Pearson. Los valores de VO2max obtenidos en el test de medida directa no presentaron diferencias significativas en relación a la medida indirecta (62,8 ± 10,1 vs. 58,5 ± 8,5 ml/kg/min, respectivamente). Cuando correlacionamos los valores de VO2max obtenidos en ambos tests, observamos una fuerte correlación (r = 0,72). En conclusión, los tests de medida indirecta presentaron buena aceptación para los atletas de futsal, teniendo en vista la alta correlación con los tests de medida directa, el bajo costo de su aplicación y el apercibimiento de las informaciones importantes que puedem auxiliar la prescrición de el no acompañamiento del entrenamiento. Abstract in english The importance of the morphofunctional qualities to greater efficiency in sports has increased the interest on the improvement on the physical fitness levels of athletes. However, not many studies on the physiological variables of indoor soccer are available in the world scientific literature. Thus, [...] the objective of this work was to verify the existence of correlation between the direct and indirect VO2max measurement tests in indoor soccer players. Thirteen indoor soccer players with age of 18.6 ± 1.9 years, height of 177.1 ± 3.5 cm, weight of 68.5 ± 9.5 kg and body mass index (BMI) of 21.7 ± 2.3 kg/m² were analyzed. For the direct VO2max

Anna Myrna Jaguaribe de, Lima; Daniele Vanusca Gomes, Silva; Alexandre Oscar Soares de, Souza.

2005-06-01

217

Raman studies of Eu3+ doped GdVO4  

International Nuclear Information System (INIS)

Full text: Eu3+ doped GdVO4 nanoparticles are used as red-emitting materials in many optical applications. It crystallizes in tetragonal system with space group I41/ amd. It composes of a VO43- tetrahedron, in which V ion is tetrahedrally co-ordinated with O ions, and a distorted dodecahedron (eightfold coordination), in which Gd ion is linked to eight O ions. There are not many reports on relationships between luminescence and vibrational modes of V-O, Gd-O. In this paper, Raman studies of Eu3+ doped GdVO4 nanoparticles prepared by urea hydrolysis in ethylene glycol medium and subsequently heat-treated at 500 and 900 deg C are reported. The particle sizes of 500 and 900 deg C pure GdVO4 samples, as determined from XRD studies are 47 and 90 nm respectively. Raman spectra of pure-GdVO4 and Eu3+ doped GdVO4 nanoparticles heat treated at 500 and 900 deg C are shown. Pure GdVO4 heated at 500 deg C shows intense peaks at 110, 123, 153, 245, 260, 381, 437 and 477 cm-1. While the peaks at 153, 243, 260 and 381 cm-1 correspond to B1g, Eg, B2g and A1g modes, the origin of peaks at 110 and 123 cm-1 is not very clear. When heated at 900 deg C the peak at ? 110 cm-1 disappears, indicating that this may be related to nano-size effects. In 500 and 900 deg C Eu3+ doped GdVO4 samples, the peaks at 153 and 437 cm-1 becomes weaker as Eu3+ concentration increases. Additional peaks around 190-202 cm-1 appears to be related to the luminescence due to Eu3+, as the peak intensity increases with increase in Eu3+ concentration from 2 to 5 at. %. Further addition of Eu3+ it results in a decrease in intensity, and may be attributed to the concentration-quenching effects

218

NVO LITE - Harnessing the VO for Education  

Science.gov (United States)

Spectroscopy is probably the most important tool used by astronomers to disentangle the nature of the universe. However, it is one of the most challenging subjects for undergraduates to understand. Students often seem baffled by the connection between a spectrum seen visually as a color band and the same spectrum plotted graphically as intensity versus wavelength or frequency. Because of this, we are currently developing a suite of spectroscopic tools for astronomy education as part of Project LITE (Light Inquiry Through Experiments). We are also assessing the effectiveness of these tools in improving conceptual understanding of spectral phenomena by undergraduates taking introductory astronomy courses. Project LITE includes take-home laboratory materials and experiments that are integrated with web-based software. A core software application - the Spectrum Explorer (SPEX) - makes possible the creation and analysis of spectra using drawing, blackbody, power law and other tools. The first release of SPEX runs as a Java applet. It is being extended to act as a client of the Spectrum Services of the Virtual Observatory and run as an application under Java Web Start. This development will help enable students to work with the VO catalogues that include the full range of spectra of essentially all known types of astronomical objects. Students will then be able to perform undergraduate astronomy exercises (such as the Hubble law and spectral classification) using real data. They will also be put in a position to be able to carry out original research of their own. SPEX (along with many other applets about both the physical and perceptual nature of light) can be found at the LITE web site http://lite.bu.edu. Project LITE is supported by NSF Grant #DUE-0125992. E. W. is supported by a NASA Graduate Student Research Fellowship, NASA Grant number NGT5-60482.

Brecher, K.; Weeks, E.; Carr, P.

2004-12-01

219

Proposal of Secure VoIP System Using Attribute Certificate  

Science.gov (United States)

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.

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

220

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-06-15

 
 
 
 
221

Efecto de nutrientes sobre la producción de biomasa del hongo medicinal Ganoderma lucidum / Effect of nutrients in the biomass production of the medicinal mushroom Ganoderma lucidum  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish 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 niv [...] el 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. Abstract in english Ganoderma 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 micronutrien [...] ts sources, on fungal biomass production, were evaluated. Using glucose and peptone as carbon and nitrogen sources, respectively, an optimal C/N ratio of 16,7:1 was found, for which the maximal biomass production was 25 g/L. Replacing glucose by lactose or barley flour and peptone by yeast extract at the same C/N ratio, the biomass production was enhanced to 35 g/L. With barley flour in the culture medium, the presence of Mg and K salts and thiamine did not turn out into a major increase of biomass. The G. lucidum biomass production is promoted by C/N ratios in the culture medium nearly equivalent to that found in the fungus, as well as the presence of complex substrates as barley flour which, additionally, contributes with important micronutrients along with the carbon source.

Ana María, Torres López; Juan Carlos, Quintero Díaz; Lucía, Atehortua Garcés.

2011-07-01

222

La biomasa de los cultivos en el oecosistema. Sus beneficios agroecológicos / The biomass of the cultivations in the agroecosistema. Its benefits agroecological  

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish 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 revolució [...] n 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; por que 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. Abstract in english Biomass is the result of the transformation of solar energy into chemical energy. The man throughout history has used not only for food but also for feeding their animals. The progress of science promoted agricultural development based on the green revolution, which only promotes the production of e [...] ither food or feed, marginalizing the importance of biomass as enriching the soil resources available inputs needed to replace their fertility natural. At present the production and preservation of any crop biomass becomes transcendent importance, because it also contributes to environmental protection through carbon sequestration. This study aimed to show the importance of providing non-food biomass generally for humans to use it not only as animal feed but also as a natural resource rich soil. Research in Cuba on the subject is poor, even though today is very important to find alternatives to deepen in the production of biomass in relation to the environment. Finally, we present preliminary results on the production of biomass from agricultural biodiversity present in production scenarios, while reflecting on the important question for future research.

Anirebis, Martínez Romero; Angel, Leyva Galán.

2014-03-01

223

Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition  

Science.gov (United States)

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.

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

2014-09-01

224

A VO-driven Astronomical Data Grid in China  

CERN Document Server

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

Cui, Chenzhou; Yang, Yang; Zhao, Yongheng

2010-01-01

225

Electrical conduction in PrVO/sub 4/ single crystal  

Energy Technology Data Exchange (ETDEWEB)

In this paper studies on electrical conductivity and dielectric constant of PrVO/sub 4/ single crystal above room temperature, i.e. 300 to 1000 K, are reported. Single crystals of PrVO/sub 4/ were grown by the flux method. Details about the crystal growth and identification are given elsewhere. The single crystals of PrVO/sub 4/ have a light green colour. The two probe method was used for the electrical conductivity measurements because, due to the small size of the crystal, the four-probe method could not be used. The measurements were made perpendicular to the c axis. The dielectric constant was calculated by measuring capacitance of the capacitor formed with the crystal as a dielectric medium. The measurement of capacitance was taken by a Ruttonsaw Simpson Universal LCR Bridge model 90I India. Experimental details are given. Results are given and discussed.

Yadava, Y.P.; Singh, R.A. (Gorakhpur Univ. (India). Dept. of Physics); Wanklyn, B.M. (Oxford Univ. (UK). Clarendon Lab.)

1985-02-01

226

Speciation in the aqueous H+/H2VO4-/H2O2/picolinate system relevant to diabetes research.  

Science.gov (United States)

A detailed study of the quaternary aqueous H+/H2VO4-/H2O2/picolinate (Pi-) system has been performed at 25 degrees C in 0.150 M Na(Cl) medium using quantitative 51 V NMR (500 MHz) and potentiometric data (glass electrode). In the ternary H+/H2VO4-/Pi- system, six complexes have been found in the pH region 1-10. In the quaternary H+/H2VO4-/H2O2/Pi- system, eight additional complexes have been found. Generally, equilibria are fast in both systems. The rate of peroxide decomposition depends on the species in solution. Chemical shifts, compositions and formation constants for the species are given. Equilibrium conditions and the fit of the model to the experimental data are illustrated in distribution diagrams. Possible formation of mixed ligand species with imidazole, lactic acid and citric acid have been investigated and ruled out under the same experimental conditions. Structural proposals are given, based on 1)C NMR data and available crystal structures. PMID:15252549

Andersson, Ingegärd; Gorzsás, András; Pettersson, Lage

2004-02-01

227

Componente lento da cinética do VO2: determinantes fisiológicos e implicações para o desempenho em exercícios aeróbios / Slow component of VO2 kinetics: physiological determinants and implications for performance in aerobic exercises  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A cinética do consumo de oxigênio (VO2) e a resposta do lactato sanguíneo durante o exercício de carga constante em diferentes intensidades permitem caracterizar os domínios moderado, pesado e severo do exercício. Em exercício de intensidade constante, o perfil da resposta do VO2, analisada por ajus [...] tes exponenciais, apresenta as fases cardiodinâmica, fundamental e lenta. A ocorrência do componente lento (CL) tem sido associada a fatores como recrutamento de fibras do tipo II e acúmulo de metabólitos, como lactato, íons H+, fosfato inorgânico e ADP. O CL expressa uma redução da eficiência muscular e tem sido associado à menor tolerância de exercícios aeróbios de intensidade alta. O presente estudo teve por objetivo detalhar a fundamentação teórica sobre sua ocorrência, a influência na tolerância ao exercício, bem como prover os diferentes procedimentos adotados em sua quantificação. Abstract in english Oxygen uptake (VO2) kinetics and blood lactate response during constant workload exercise at different intensities allow characterizing the moderate, heavy and severe exercise domains. In constant-intensity exercise, the VO2 response profile, analyzed by exponential fits, shows the cardiodynamic, fu [...] ndamental and slow phases. The occurrence of the slow component (SC) has been associated with factors such as the recruitment of type II fibers and the accumulation of metabolites such as lactate, ions H+, inorganic phosphate and adenosine diphosphate. The SC expresses a reduction of muscular efficiency and has been associated with lower tolerance to high-intensity aerobic exercise. The present study aimed to detail the theoretical framework of its occurrence and its influence on exercise tolerance, as well as providing the different procedures used in its quantification.

Renato Aparecido Correa, Carita; Dalton Muller, Pessoa Filho; Luis Fabiano, Barbosa; Camila Coelho, Greco.

228

Influence of Prior Exercise on VO2 Kinetics Subsequent Exhaustive Rowing Performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercise time during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderate exercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longer exercise time ...

Sousa, Ana; Ribeiro, Joa?o; Sousa, Marisa; Vilas-boas, Joa?o Paulo; Fernandes, Ricardo J.

2014-01-01

229

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Bereka Shewara, Jemil

2012-01-01

230

Análisis de la biomasa de raíces en diferentes tipos de bosques: Avances en la evaluación de Pinus radiata en Chile Root biomass analysis in different forest types: research advances in the Chilean radiata pine forest  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se evaluó la biomasa de raíces en la especie Pinus radiata (D. Don) en dos condiciones de sitio diferentes en Chile central, utilizando el índice raíz/vástago (proporción de raíces respecto de la biomasa aérea). Además, se analizó literatura referida a la proporción de sistemas radicales con el propósito de inferir el efecto de especies y medio ambiente sobre el desarrollo de raíces. Se cosecharon 27 individuos de Pinus radiata de diferentes edades en un rango de 3 hasta 23 años...

Javier Guerra, C.; Jorge Gayoso, A.; Juan Schlatter, V.; Roberto Nespolo, R.

2005-01-01

231

Acumulación y distribución de biomasa en Leucaena leucocephala (lam) de Wit., durante la fase de establecimiento. I. Repartición de biomasa / Accumulation and distribution of biomass in Leucaena leucocephala (Lam.) de wit during the phase of establishment. II. Repartitioning of biomass  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish En el presente estudio se comparó el patrón de acumulación de biomasa aérea y radical durante los primeros 110 días después de la germinación (DDG), en tres líneas de Leucaena leucocephala (CIAT 7984, 9438, 18477). El cv. Perú se utilizó como testigo con fines de comparación. El experimento se llevó [...] a cabo en condiciones de invernadero, cultivándose las plantas en tubos de PVC de 1 m de alto por 0.20 m de ancho. El diseño del experimento fue un completamente aleatorizado, en un arreglo factorial de 4 líneas x 5 cosechas (15, 30, 45, 60 y 110 DDG) x 5 repeticiones. Los datos fueron analizados por vía no paramétrica. Para estimar el patrón de acumulación y distribución de biomasa se midió en cada cosecha el peso seco acumulado de hojas (MSh), tallos (MSt) y raíces (MSr). A los 110 DDG, todas las líneas en general destinaron una mayor proporción de asimilados en producir hojas a expensa de tallos y raíces. La MSh no fue diferente (P Abstract in english In the present study, dry matter accumulation and the pattern of distribution between aerial and bellow-ground biomass were studied in three accessions (CIAT 7984, 9438, 18477) of Leucaena leucocephala during 110 days after germination (DAG). Cv. Perú was used as a control plant. The experiment was [...] carried out under glasshouse conditions, where plants were grown in PVC pots (1 m height x 0.20 m diameter). A completed randomized designed was used, in a factorial arrangement of 4 plant materials x 5 harvests (ie. 15, 30, 45, 60 and 110 DAG) x 5 replicates. To estimate biomass accumulation and assimilates distribution within the plant, harvests of individual plants were performed and the dry weight of leaf (LDM), stems (SDM) and root (DMR) at different depths was recorded. Initially, all accessions diverted a high proportion of the available energy in producing root biomass, while by the end of the establishment period relatively more photosynthetic material was used to increase leaf and stem biomass. The MSh was not different (P

Eunice, Guevara; Orlando, Guenni.

2004-04-01

232

Phase Transformation of VO2 Nanoparticles Assisted by Microwave Heating  

Science.gov (United States)

The microwave assisted synthesis nowadays attracts a great deal of attention. Monoclinic phase VO2 (M) was prepared from NH4VO3 and H2C2O4 · 2H2O by a rapid microwave assisted technique. The synthesis parameters, microwave irradiation time, microwave power, and calcinations temperature were systematically varied and their influences on the structure and morphology were evaluated. The microwave power level has been carried out in range 180–600?W. TEM analysis demonstrated nanosized samples. The structural and morphological properties were measured using XRD, TEM, and thermal analyses. The variations of vanadium phase led to thermochromic properties. PMID:24688438

Sikong, Lek.

2014-01-01

233

Metodología de diseño e implementación de soluciones voIP  

Directory of Open Access Journals (Sweden)

Full Text Available El presente documento ilustra metodológicamente el diseño y la implementación de una solución VoIP, la cual integra la planta análoga (PBX con el modulo de PBX del Elastix (IP-PBX, por medio de un Gateway de VoIP. Con el producto de esta investigación, desarrollada por el grupo INTEGRA, se permite el uso de nuevos servicios enfocados en el óptimo uso de las redes (telefonía y datos usando servicios adicionales, como son: servidor de fax, servidor de mensajería instantánea, control y reporte detallado de llamadas, grabaciones y servicios adicionales como la recepción de fax y buzón de mensajes al correo electrónico como archivos adjuntos.

Wilson A. Bulla B.

2012-12-01

234

Lightweight security mechanism for PSTN-VoIP cooperation  

CERN Document Server

In this paper we describe a new, lightweight security mechanism for PSTN-VoIP cooperation that is based on two information hiding techniques: digital watermarking and steganography. Proposed scheme is especially suitable for PSTN-IP-PSTN (toll-by-passing) scenario which nowadays is very popular application of IP Telephony systems. With the use of this mechanism we authenticate end-to-end transmitted voice between PSTN users. Additionally we improve IP part traffic security (both media stream and VoIP signalling messages). Exemplary scenario is presented for SIP signalling protocol along with SIP-T extension and H.248/Megaco protocol.

Mazurczyk, W; Mazurczyk, Wojciech; Kotulski, Zbigniew

2006-01-01

235

Infrared-sensitive electrochromic device based on VO2  

Science.gov (United States)

The field-effect transistor (FET) provides an electrical switching function of current flowing through a channel surface by external voltage. Here, we report on a field-effect device that enables electrical switching of optical transmittance as well as conventional electrical current. We investigated optical properties of vanadium dioxide (VO2) thin film under the presence of electric field generated at the interface between VO2 and ionic liquid in a FET geometry, and found that the device exhibits clear electrochromic effect with large ON/OFF contrast only in the infrared region, potentially beneficial for energy-saving smart window applications as a voltage-tunable transparent heat-cutting filter.

Nakano, M.; Shibuya, K.; Ogawa, N.; Hatano, T.; Kawasaki, M.; Iwasa, Y.; Tokura, Y.

2013-10-01

236

Speciation in the aqueous H+/H2VO4-/H2O2/citrate system of biomedical interest.  

Science.gov (United States)

The speciation in the quaternary aqueous H+/H2VO4-/H2O2/citrate (Cit3-) and H+/H2VO4-/Cit3-/L-(+)-lactate (Lac-) systems has been determined at 25 degrees C in the physiological medium of 0.150 M Na(Cl). A combination of 51V NMR integral intensities and chemical shift (Bruker AMX500) as well as potentiometric data (glass electrode) have been collected and evaluated with the computer program LAKE, which is able to treat multimethod data simultaneously. The pKa-values for citric acid have been determined as 2.94, 4.34 and 5.61. Altogether six vanadate-citrate species have been found in the ternary H+/H2VO4-/Cit3- system in the pH region 2-10, only two of which are mononuclear. Reduction of vanadium(V) becomes more pronounced at pH decomposition of peroxide in acidic solutions limited the final model to pH > 4. In the quaternary H+/H2VO4-/Cit3-/Lac- system, two mixed-ligand species have been determined, with the compositions V2CitLac2- and V2CitLac3- (pKa = 5.0). To our knowledge, this is the first time such complexes have been reported for vanadium(V). 51V NMR chemical shifts, compositions and formation constants are given, and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data. When suitable, structural proposals are given, based on 13C NMR measurements and available literature data of related compounds. PMID:15349160

Gorzsás, András; Getty, Kendra; Andersson, Ingegärd; Pettersson, Lage

2004-09-21

237

Potentiometric parameters of a PVC-NaV6O15 - graphite electrode  

International Nuclear Information System (INIS)

The behavior of the film electrodes on the base of polyvinyl chloride (PVC), modified by bronze of the NaV6O15 (Na0.33V2O5) composition is studied. The electrodes are selective to the pentavalent vanadium ions in acid and neutral media. It is shown, that the sensitive area of concentrations is within the frames of 10-2-10-5 M. The potential dependence on concentration is subjected to the Hernst equation with the 59.4±0.8 mV/pc angular coefficient corresponding to the VO2+ ? VO2+ single electron transition by ph 1.5-2.0 (cation function). Dependence of the potential on concentration, corresponding to the VO3- ? VO2+ transition (anion function), the angular coefficient -58.0±0.7 mV/pc, is observed by ph 5.0-6.0

238

Alterações na produção de compostos fenólicos em culturas de células de Vitis vinifera eliciadas por Phaeomoniella chlamydospora  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A esca é uma doença que afecta plantas da espécie Vitis vinifera levando a importantes perdas na produção de vinho. O fungo Phaeomoniella chlamydospora (PC) é frequentemente associado a plantas de videira com esca e declínio das vinhas. Informação sobre a interacção deste fungo com a esca e declínio das vinhas ainda é escassa. Para estudar mecanismos de defesa da videira ao fungo PC utilizamos culturas in vitro de Vitis vinifera cv. Vinhão (Vv) eliciadas com biomasa autoclava...

Lima, M. R. M.; Guimara?es, Orlando; Ferreres, Federico; Dias, Alberto Carlos Pires

2004-01-01

239

Producción de biomasa de Saccharomyces cerevisiae y Candida utilis usando residuos de pulpa de Coffea arabica L  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Los avances en biotecnología industrial ofrecen oportunidades potenciales para la utilización económica de residuos agro-industriales tales como la pulpa de café, material mucilaginoso, fibroso (producto secundario) obtenido durante el proceso húmedo o seco del beneficio de las cerezas de café. El p [...] ropósito de este trabajo fue utilizar los residuos de la pulpa de café, rico en materia orgánica, como sustrato para la producción de biomasa de levaduras por procesos de fermentación aeróbica. Los residuos de café se sometieron a hidrólisis con una solución de ácido sulfúrico al 2%, en una relación 10:1 (líquido:sólido), con un tamaño de partícula ? 2 mm., operando a presión atmosférica, ebullición a reflujo, durante 4 horas. El extracto ácido se filtró y se ajustó a pH 4,5 y luego se esterilizó a 120 ºC por 15 minutos. La fermentación se realizó con Saccharomyces cerevisiae y Candida utilis, medio de producción extracto de café enriquecido con sales nutritivas. Se formularon diferentes medios de producción (1,2,3 y 4), siendo el N°3, enriquecido con extracto de café hidrolizado, 1L; urea, 3g/L; fosfato ácido de potasio, 2g/L; extracto de malta, 1,3g/L y melaza, 30g/L, el cual aportó los mejores resultados. El tiempo total de fermentación fue de 8 horas. Se obtuvo 10g/L de biomasa con un incremento proteico de 7,39 a 42,5%. Se puede concluir que la pulpa de café constituye un sustrato adecuado para obtener biomasa o proteína unicelular, que podría ser destinada como suplemento en formulaciones para alimentación animal Abstract in english The advances in industrial biotechnology offer potential opportunities for the economic use of agro-industrial remainders such as the coffee pulp, mucilagenous, fibrous material (secondary product) obtained during the humid or dry process of the benefit of the coffee cherries. The intention of this [...] work was to use the remainders of the pulp of coffee, rich in organic matter, like substrate for the production of biomass of leavenings by processes of aerobic fermentation. The coffee remainders were put under hydrolysis with a sulfuric acid solution to 2%, in a 10:1 relation (liquid: solid), with a size of particle ? 2 mm, operating to atmospheric pressure, boiling to ebb tide, during 4 hours. The acid extract filtered and it adjusted to pH 4,5 and then it sterilize to 120 ºC by 15 minutes. The fermentation was made with Saccharomyces cerevisiae and Candida utilis, the production means: extract of coffee enriched with nutritious salts. Different means from production were formulated (1,2,3 and 4), being the N°3, enriched with extract of hydrolyzed coffee, 1L; urea, 3g/L; acid potassium phosphate, 2g/L; extract of Malta, 1,3g/L and molasses, 30g/L, which contributed the best results. The total time of fermentation was of 8 hours. 10g/L of biomass with a protein increase from 7.39 to 42.5% was obtained. It is possible to be concluded that the coffee pulp constitutes an suitable substrate to obtain biomass or unicellular protein, that could be destined like supplement in formulations for feeding animal

María J, Gualtieri A; Carolina, Villalta R; Lorena E, Díaz T; Gerardo, Medina; Elisa, Lapenna; María E, Rondón.

2007-12-01

240

Eliminación de cadmio (II) en agua mediante el uso de biomasa de pomelo (Citrus paradisi L.) en estado natural y protonado : Isotermas y cinética de adsorción  

Digital Repository Infrastructure Vision for European Research (DRIVER)

El presente Trabajo Fin de Máster tiene como objetivo principal, realizar estudio más exhaustivo de la capacidad de adsorción de polvo de pomelo como extractante natural y de bajo coste, siendo este un residuo de la industria alimentaria, para la eliminación de cadmio (II) en disolución acuosa. Para ello emplearemos una biomasa de pomelo en su forma natural y tratada con ácido sulfúrico, denominada forma protonada. En este contexto, se plantean los siguientes objetivos: 1.Descrip...

Esteban Cruz, Gine?s

2013-01-01

 
 
 
 
241

Determinación de carbono orgánico total presente en el suelo y la biomasa de los páramos de las comunidades de chimborazo y shobol llinllin en Ecuador  

Digital Repository Infrastructure Vision for European Research (DRIVER)

En la determinación del contenido de carbono orgánico total presente en el suelo y la biomasa (cobertura vegetal) de los páramos de las comunidades de Chimborazo, con 210ha de páramo cuya ubicación es 746667UTM-9825400UTM, y Shobol Llinllín, con 350 ha de páramo, 754680UTM–9854678UTM, pertenecientes a San Juan en Ecuador, se seleccionaron 9 puntos de muestreo de acuerdo a la variación, características y altitud del suelo, repartidos para este estudio en tres pisos altitudinales com...

Echeverri?a, M.; Recalde, C.; Alvarez, G.; Inga, C.; Cunalata, C.

2013-01-01

242

Determinación de las reservas de carbono en la biomasa aérea de sistemas agroforestales de theobroma cacao l. en el departamento de San Martìn, Perú  

Digital Repository Infrastructure Vision for European Research (DRIVER)

En este estudio se evaluó la biomasa aérea en seis diferentes sistemas agroforestales de cacao (Theobroma cacao L.) asociado con especies forestales maderables y frutales; con el propósito de conocer el potencial de captura de carbono por cada sistema. El estudio se realizó en dos diferentes sitios ubicados en la región San Martín (provincias de San Martín y Mariscal Cáceres). Los sistemas agroforestales estimados presentaron edades de 5, 12 y 20 años. En cada sistema se ...

Concha, Juanita Y.; Alegre, Julio C.; Vicente Pocomucha

2007-01-01

243

Efeito de diferentes misturas de substratos orgânicos na biomassa e no óleo essencial de Thymus zygis / Effect of different mixtures of organic substrates on the biomass and essential oil of Thymus zygis  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: Portuguese Abstract in portuguese Neste ensaio avaliou-se o efeito de diferentes misturas de substrato comercial e vermicomposto na produção de biomassa, composição química e rendimento dos óleos essenciais de Thymus zygis. Utilizaram-se 5 substratos resultantes da mistura de um vermicomposto (V) com um substrato orgânico comercial [...] (O), em cinco proporções diferentes (v/v): V100 (100%V); VO75-25 (75%V+25%O); VO50 -50 (50%V+50%O); VO 25-75 (25%V + 75%O) e O100 (100%O). A inclusão do vermicomposto no substrato não melhorou a produção de biomassa. Na modalidade O100 produziu-se mais biomassa, tendo sido na modalidade VO25-75 onde se obteve o valor mais baixo. Na modalidade V100 todas as plantas secaram tendo-se ainda apresentado nesta modalidade o valor mais elevado de pH e de densidade real e inversamente o menor valor de espaço poroso total. Os monoterpenos oxigenados predominaram nos óleos extraídos das plantas nas modalidades O100 e VO25-75, contrariamente ao que se verificou para os monoterpenos não oxigenados tendo estes predominado nas modalidades VO75-25 e VO50-50. A concentração de timol foi elevada nas misturas testadas, em particular na modalidade VO25-75. Abstract in english In this trial we evaluated the effect of different mixtures of organic growing media substratum and vermicompost and their physical properties on biomass, chemical composition and yield of essential oils of Thymus zygis. Five treatments were established based on two types of organic materials (O, co [...] mmercial growing media, and V, vermicompost). The following proportions were studied (v/v): V100 (100%V); VO75-25 (75%V+25%O); VO50-50 (50%V+50%O); VO 25-75 (25%V+75%O) and O100 (100%O). The inclusion of vermicompost did not improve biomass production. The treatment O100 produced more biomass and the lowest was obtained in VO25-75. On V100 treatment all plants were dead and also have showed the highest pH and particle density and conversely presented the lowest value of total pore space. Oxygenated monoterpenes predominated in the oils extracted from plants in O100 and VO25-75, contrary to what was found for non-oxygenated monoterpenes having these prevailed in VO75-25 and VO50-50. The concentration of thymol was high in the mixtures tested, particularly in VO25-75.

Nelson, Lourenço; Susana A., Dandlen; Maria G., Miguel; Ana, Figueiredo; José, Barroso; Luis, Pedro; Luísa, Coelho; Mário, Reis; Pedro J., Correia.

2011-07-01

244

BIOMASA, DENSIDAD Y COMPOSICION ZOOPLANCTONICA DE LA BAHIA DE MOCHIMA, VENEZUELA Zooplankton biomass, density and composition in Mochima Bay, Venezuela  

Directory of Open Access Journals (Sweden)

Full Text Available La biomasa, densidad y composición del zooplancton de la bahía de Mochima fueron estudiadas durante 1998. Las muestras fueron recolectadas mensualmente en la entrada de la bahía (estación A y en la parte interna (estación B entre enero y diciembre de 1998. En cada estación se realizaron calados oblicuos con una malla estándar de 300 micras y 0,25 m de diámetro de boca a 0-5 y 10-15 m y a una velocidad de dos nudos durante 10 min. El índice de surgencia se calculó a partir de los datos de vientos. Se midió salinidad, temperatura del agua, concentración de oxígeno disuelto, concentración de clorofila a, biomasa y densidad del zooplancton; además se identificaron los organismos, en lo posible hasta especie. Los perfiles de temperatura mostraron un mayor tiempo de permanencia de aguas cálidas superficiales en la estación más interna. Los valores más altos de densidad zooplanctónica (4066 ind/m³ se registraron en el período febrero - mayo y luego los valores fueron relativamente bajos (Zooplankton biomass, density and composition were studied in Mochima Bay during 1998. Samples were collected at monthly intervals at stations located at the mouth and the interior of the bay from January to December 1998. At each station, samples were collected in the intervals 0-5 and 10-15 m with a Standard net of 300 µm and 0,25 m Ø at a speed of two knots during ten minutes. Wind data was used to calculate the upwelling index. Salinity, water temperature, concentration of dissolved oxygen and chlorophyll a (chl a, and zooplankton biomass and density were measured at the two stations. Also, the organisms were identified to group level. Temperature profiles showed a greater residence time for warm waters in the internal part of the bay than in the external one. Higher zooplankton density values (4066 ind/m³ were found during the period February - May. Values were relatively low (< 200 ind/m³ in June and July for both stations. They were also low for the external station in the period October - December. The highest zooplankton density was measured in the layer 10-15m in the internal station. Dominance pattern was similar for both stations. Eighteen zooplankton groups were identified. The order of importance of the groups in terms of relative abundance was copepods, apendiculates, balanid nauplii and cladocerans. The latter dominated from July to September (warm-water period at the internal station. The variation in zooplankton density and composition reflected a strong influence of the upwelling index and of water temperature.

Brightdoom Márquez-Rojas

2008-06-01

245

BIOMASA, DENSIDAD Y COMPOSICION ZOOPLANCTONICA DE LA BAHIA DE MOCHIMA, VENEZUELA / Zooplankton biomass, density and composition in Mochima Bay, Venezuela  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish La biomasa, densidad y composición del zooplancton de la bahía de Mochima fueron estudiadas durante 1998. Las muestras fueron recolectadas mensualmente en la entrada de la bahía (estación A) y en la parte interna (estación B) entre enero y diciembre de 1998. En cada estación se realizaron calados ob [...] licuos con una malla estándar de 300 micras y 0,25 m de diámetro de boca a 0-5 y 10-15 m y a una velocidad de dos nudos durante 10 min. El índice de surgencia se calculó a partir de los datos de vientos. Se midió salinidad, temperatura del agua, concentración de oxígeno disuelto, concentración de clorofila a, biomasa y densidad del zooplancton; además se identificaron los organismos, en lo posible hasta especie. Los perfiles de temperatura mostraron un mayor tiempo de permanencia de aguas cálidas superficiales en la estación más interna. Los valores más altos de densidad zooplanctónica (4066 ind/m³) se registraron en el período febrero - mayo y luego los valores fueron relativamente bajos ( Abstract in english Zooplankton biomass, density and composition were studied in Mochima Bay during 1998. Samples were collected at monthly intervals at stations located at the mouth and the interior of the bay from January to December 1998. At each station, samples were collected in the intervals 0-5 and 10-15 m with [...] a Standard net of 300 µm and 0,25 m Ø at a speed of two knots during ten minutes. Wind data was used to calculate the upwelling index. Salinity, water temperature, concentration of dissolved oxygen and chlorophyll a (chl a), and zooplankton biomass and density were measured at the two stations. Also, the organisms were identified to group level. Temperature profiles showed a greater residence time for warm waters in the internal part of the bay than in the external one. Higher zooplankton density values (4066 ind/m³) were found during the period February - May. Values were relatively low (

Brightdoom, Márquez-Rojas; Baumar, Marín; J.R, Díaz-Ramos; Luis, Troccoli.

2008-06-01

246

Variaciones de abundancia y biomasa del zooplancton en un embalse tropical oligo-mesotrófico del norte de Venezuela  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish La abundancia del zooplancton en los embalses está determinada principalmente por la velocidad y el contenido del agua, pero se sabe relativamente poco sobre los embalses tropicales. Se estudió la distribución temporal y espacial de la abundancia y la biomasa del zooplancton en el eje longitudinal d [...] el embalse de Clavellinos, en el norte de Venezuela, entre octubre 2006 y septiembre 2007. El zooplancton fue recolectado en el estrato oxigenado con una red de plancton. Un total de 16 taxones fueron identificados: Copepoda, Cladocera, Rotifera, Ostracoda y Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida) dominó la comunidad, mientras que los rotíferos fueron los más diversos, con 10 especies. La abundancia del zooplancton varió de 31 a 101ind/l en E1, 36 a 84ind/l en E2, y, de 30 a 250ind/L en el E3. La biomasa varió de 97,4 a 1406.3?g/l en E1, 108,5 a 397.2?g/l en E2, y de 25,9 a 763.9?g/l en el E3. Esta comunidad de zooplancton pareci? responder a las variaciones ambientales en el embalse, m?s que a las variaciones en la disponibilidad de recursos. Abstract in english Variations of zooplankton abundance and biomass in a tropical oligo-mesotrophic reservoir in Northern Venezuela. Zooplankton abundance in reservoirs is mainly determined by the speed and content of the water, but relatively little is known regarding tropical reservoirs. We studied the seasonal and s [...] patial distribution of zooplankton abundance and biomass along the longitudinal axis of Clavellinos reservoir, northern Venezuela, from October 2006 to September 2007. Zooplankton was collected from the oxygenated layer using a plankton net. A total of 16 taxa were identified: Copepoda, Cladocera, Rotifera, Ostracoda and Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida) dominated the community, while rotifers were the most diverse, with 10 species. Zooplankton abundance varied from 31 to 101ind/L in E1, 36 to 84ind/L in E2, and, from 30 to 250ind/L in E3. Biomass varied from 97.4 to 1406.3?g/l in E1, 108.5 to 397.2?g/l in E2, and from 25.9 to 763.9?g/l in E3. This zooplankton community seems to respond to environmental variations in the reservoir, rather than to variations in resource availability. Rev. Biol. Trop. 58 (2): 603-619. Epub 2010 June 02.

Sandra, Merayo; Ernesto J, González.

2010-06-01

247

Variaciones de abundancia y biomasa del zooplancton en un embalse tropical oligo-mesotrófico del norte de Venezuela  

Directory of Open Access Journals (Sweden)

Full Text Available La abundancia del zooplancton en los embalses está determinada principalmente por la velocidad y el contenido del agua, pero se sabe relativamente poco sobre los embalses tropicales. Se estudió la distribución temporal y espacial de la abundancia y la biomasa del zooplancton en el eje longitudinal del embalse de Clavellinos, en el norte de Venezuela, entre octubre 2006 y septiembre 2007. El zooplancton fue recolectado en el estrato oxigenado con una red de plancton. Un total de 16 taxones fueron identificados: Copepoda, Cladocera, Rotifera, Ostracoda y Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida dominó la comunidad, mientras que los rotíferos fueron los más diversos, con 10 especies. La abundancia del zooplancton varió de 31 a 101ind/l en E1, 36 a 84ind/l en E2, y, de 30 a 250ind/L en el E3. La biomasa varió de 97,4 a 1406.3?g/l en E1, 108,5 a 397.2?g/l en E2, y de 25,9 a 763.9?g/l en el E3. Esta comunidad de zooplancton pareci? responder a las variaciones ambientales en el embalse, m?s que a las variaciones en la disponibilidad de recursos.Variations of zooplankton abundance and biomass in a tropical oligo-mesotrophic reservoir in Northern Venezuela. Zooplankton abundance in reservoirs is mainly determined by the speed and content of the water, but relatively little is known regarding tropical reservoirs. We studied the seasonal and spatial distribution of zooplankton abundance and biomass along the longitudinal axis of Clavellinos reservoir, northern Venezuela, from October 2006 to September 2007. Zooplankton was collected from the oxygenated layer using a plankton net. A total of 16 taxa were identified: Copepoda, Cladocera, Rotifera, Ostracoda and Diptera. Thermocyclops decipiens (Copepoda, Cyclopoida dominated the community, while rotifers were the most diverse, with 10 species. Zooplankton abundance varied from 31 to 101ind/L in E1, 36 to 84ind/L in E2, and, from 30 to 250ind/L in E3. Biomass varied from 97.4 to 1406.3?g/l in E1, 108.5 to 397.2?g/l in E2, and from 25.9 to 763.9?g/l in E3. This zooplankton community seems to respond to environmental variations in the reservoir, rather than to variations in resource availability. Rev. Biol. Trop. 58 (2: 603-619. Epub 2010 June 02.

Sandra Merayo

2010-06-01

248

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

Directory of Open Access Journals (Sweden)

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

Sánchez O. M.

2004-04-01

249

TRENDS IN THE EDUCATIONAL ACHIEVEMENT OF SLOVAK STUDENTS IN PHYSICS IN THE TIMSS STUDY / Trendy vo vzdelávacích výsledkoch žiakov Slovenskej republiky z fyziky vo výskume TIMSS  

Directory of Open Access Journals (Sweden)

Full Text Available Physics is one of the Science topics, which is included to research area in the TIMSS study. The educational achievement in Physics is measured in international comparison. We present the Physics characteristics as the research area based on the content and cognitive dimension. We analyzed the trends in educational achievement between 1995 - 1999 - 2003. The article brings the findings about the overall results, the differences between boys and girls. We publish the comparison on the international level - comparison the Slovak results and ten other countries in the Europe, which had been participating in all cycles of the TIMSS study. We analyzed the student aspiration to education level as one of the factor, what has the influence on educational achievement.Fyzika patrí medzi prírodovedné predmety, ktoré tvoria výskumnú doménu medzinárodnej štúdie TIMSS. V medzinárodnom kontexte sa meria úrove? vzdelávacích výsledkov žiakov z fyziky. V ?lánku uvádzame charakteristiku fyziky ako výskumnej oblasti z poh?adu požiadaviek na hodnotenie vedomostí a zru?ností žiakov pod?a obsahovej a kognitívnej dimenzie. Prezentujeme výsledky analýzy trendov vo vzdelávacích výsledkoch žiakov z fyziky medzi rokmi 1995 – 1999 – 2003 pod?a vybraných aspektov. Uvádzame zistenia o celkových vzdelávacích výsledkoch žiakov z fyziky, o rozdieloch medzi výkonmi chlapcov a diev?at. Prezentujeme komparáciu výsledkov na medzinárodnej úrovni – porovnanie výsledkov žiakov z fyziky na Slovensku s výsledkami žiakov v desiatich vybraných európskych krajinách, ktoré sa opakovane zú?astnili výskumu TIMSS. Z faktorov pôsobiacich na vzdelávacie výsledky sme analyzovali vplyv ašpirácie žiakov k vzdelaniu, typu školy a najvyššie dosiahnutého vzdelania rodi?ov.

Kuraj Jozef

2010-10-01

250

Transport and Magnetic Properties of MgFeVO4  

Science.gov (United States)

A new spinel compound, MgFeVO4, was prepared by solid-state reactions. On the basis of the Mössbauer spectrum, it can be deduced that both Fe and V in MgFeVO4 are trivalent. Structure refinements based on X-ray and neutron diffraction data indicated that V3+ ions are likely to occupy the octahedral site, whereas Fe3+ and Mg2+ ions take both octahedral and tetrahedral sites. The formula of the compound can be represented as (Mg1-xFex)[MgxFe1-xV]O4 (x=0.638). The transport measurements indicate that MgFeVO4 is an n-type semiconductor with the hopping mechanism below 170 K and thermally activated mechanism at high temperatures. The DC and AC magnetic data show the antiferromagnetic interactions and spin glass behavior in MgFeVO4. The time-dependent magnetic relaxation and the exchange bias effect related to the spin glass phase are also analyzed. The curve fittings give long flipping times and large n values, indicating that strongly interacting clusters rather than individual spins are the predominant spin glass features.

Zhang, Xue; Kuang, Xiao-Jun; Wang, Yong-Gang; Wang, Xiao-Ming; Wang, Chun-Hai; Zhang, Yan; Chen, Chinping; Jing, Xi-Ping

2013-02-01

251

"Kogda emotsii vo mne bezuderzhno põlajut..." : [luuletused] / Jevgenia Brodneva  

Index Scriptorium Estoniae

Sisu: "Kogda emotsii vo mne bezuderzhno põlajut..." ; "Võ menja nikogda ne vstretite..." ; "Kogda nastupit vremja rasstavanja..." ; "Prosti za lozh i za obidu..." ; "Ja v plenu svoihh sobstvennõhh tshuvstv..." ; "Ot nego nelzja otkazatsja..." ; "Mne b rukoi do tebja dotjanutsja..." ; "Ja potshti, ja potshti v tebja vljublena..." ; "Ja po tebe skutshaju..."

Brodneva, Jevgenia

2003-01-01

252

Modelado de capacidades VoIP en redes corporativas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Cuesta Puebla, Miguel La

2011-01-01

253

Improving Quality of VoIP over WiMAX  

Directory of Open Access Journals (Sweden)

Full Text Available Real-time services such as VoIP are becoming popular and are major revenue earners for network service providers. These services are no longer confined to the wired domain and are being extended over wireless networks. Although some of the existing wireless technologies can support some low-bandwidth applications, the bandwidth demands of many multimedia applications exceed the capacity of these technologies. The IEEE 802.16-based WiMAX promises to be one of the wireless access technologies capable of supporting very high bandwidth applications. In this paper, we exploit the rich set of flexible features offered at the medium access control (MAC layer of WiMAX for the construction and transmission of MAC protocol data units (MPDUs for supporting multiple VoIP streams. We discuss the quality of VoIP calls, usually given by R-score, with respect to the delay and loss of packets. We analysis the quality of service (QoS on long distance data transfer between two locations with VoIP over WiMAX will be performed. Performance of selected parameters will be done using the network simulator, OPNET Modeler 14.5 [1,2].

M.A. Mohamed

2012-05-01

254

VoIP Security Syllabus and Course Outline  

Science.gov (United States)

The Center for Systems Security and Information Assurance (CSSIA) provides this zip file containing a syllabus and course outline for a VoIP security course. The syllabus document describes course objectives, structure and the intended student audience. The course outline provides information on several learning modules that would be suitable for such a course.

2013-07-29

255

Covert Channels in SIP for VoIP Signalling  

Science.gov (United States)

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

Mazurczyk, Wojciech; Szczypiorski, Krzysztof

256

Covert Channels in SIP for VoIP signalling  

CERN Document Server

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

Mazurczyk, Wojciech

2008-01-01

257

Synthesis and characterization of FeVO4 nanoparticles  

International Nuclear Information System (INIS)

Highlights: ? Simple co-precipitation method were employed for the synthesis of FeVO4. ? The calcination temperature and the reaction time were optimized. ? The effect of surfactants on the structural, morphological and magnetic properties was studied. ? The shape of the particles changes due to the effect of surfactant. ? Enhancement of magnetic orderings on the addition of surfactant. -- Abstract: Iron vanadate (FeVO4) nanoparticles were synthesized by simple co-precipitation method using various surfactants such as ethylene glycol, polyethylene glycol 200 and polyethylene glycol 400 as the structure directing agents. Systematic investigations on the structural, morphological and magnetic properties of the materials have been studied. The lattice constants of the triclinic structure of FeVO4 were calculated from the X-ray diffraction (XRD) analyses. The average grain size was estimated to be around 35 nm, which increased with increasing the calcination temperature. The stretching and bending vibrations of Fe-O were evaluated from the FT-IR spectra. Using VSM magnetometer, magnetic property was investigated through magnetic susceptibility and magnetization measurements. FeVO4 exhibits two magnetic ordering temperatures at T ? 20 K and 14 K, which is due to two different chemical environments of Fe ligands such as octahedral FeO6 and trigonal bipyramidal FeO5 in a six-column doubly bent chain, respectively.

258

Solutions to performance problems in VoIP over a 802.11 wireless LAN  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Voice over Internet Protocol (VoIP) over a wireless local area network (WLAN) is poised to become an important Internet application. However, two major technical problems that stand in the way are: 1) low VoIP capacity in WLAN and 2) unacceptable VoIP performance in the presence of coexisting traffic from other applications. With each VoIP stream typically requiring less than 10 kb/s, an 802.11b WLAN operated at 11 Mb/ s could in principle support more than 500 VoIP sessions. In actuality, no...

Wang, W.; Liew, Sc; Li, Vok

2005-01-01

259

Validade de equações de predição em estimar o VO2max de brasileiros jovens a partir do desempenho em corrida de 1.600m / Predictive equations validity in estimating the VO2max of young Brazilians from performance in a 1600 m run  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste estudo foi analisar a validade da equação proposta por Cureton et al. (1995) "VO2peak = -8.41 (MRW) + 0.34 (MRW)2 + 0.21 (Age x Gender) -0.84 (BMI) + 108.94" em estimar o VO2max de brasileiros jovens a partir de um teste de 1.600 metros, e sugerir uma equação de predição que seja es [...] pecífica para essa população. Participaram do estudo 30 homens fisicamente ativos (23 ± 3,1anos; 74,8 ± 5,8kg; 1,78 ± 0,05m; 49,8 ± 6,5mL.kg-¹.min-1) que foram submetidos a um teste incremental máximo (TI) em esteira e um teste de desempenho em corrida de 1.600 metros. Os indivíduos foram divididos em dois grupos: G1 - para gerar uma equação de predição específica para VO2max de brasileiros jovens e G2 - para aplicar ambas as equações a fim de analisar suas validades. Diferenças estatisticamente significativas foram observadas entre o VO2max determinado diretamente no TI (50,1 ± 7,1mL.kg-¹.min-¹) e os valores de VO2max obtidos pela equação proposta por Cureton et al. (44,2 ± 6,5mL.kg-¹.min-¹) com baixa correlação entre elas (r = 0,21). A relação entre VO2max e velocidade em corrida de 1.600m obtidos no G1 resultou na seguinte equação de predição: (VO2max = 0,177 * 1.600Vm(m.min-1) + 8,101). Quando essa nova equação foi aplicada nos participantes do G2, o VO2max predito (50,1 ± 7,2mL.kg-¹.min-¹) não diferiu do VO2max determinado diretamente (50,1 ± 7,1mL.kg-¹.min-¹) com alta correlação entre eles (r = 0,81). Assim, concluímos que a equação de Cureton et al. (1995), elaborada a partir de resultados de amostra norte-americana, subestimou o VO2max de brasileiros jovens e fisicamente ativos. Por outro lado, a equação proposta no presente estudo se mostrou válida para estimar o VO2max através do teste de desempenho de 1.600 metros para a população estudada. Abstract in english The aim of the present study was to analyze the validity of predictive equation proposed by Cureton et al. (1995) for VO2peak = -8.41 (MRW) + 0.34 (MRW) 2 + 0.21 (Age x Gender) -0.84 (BMI) + 108.94" on estimating the VO2max of young Brazilians from a 1600-m running performance, and to suggest a pred [...] ictive equation specific for this population. 30 physically active young men (23±3.1age; 74.8±5.8kg; 1.78±0.05m; 49.8±6.5mL.kg-¹.min-1) who were submitted to an incremental exercise test (IT) on treadmill until exhaustion with gas analysis participated in this study. Subjects also performed a 1600-m running track test as fast as possible. The volunteers were randomly sorted in two groups: G1 - to generate a specific predictive equation for VO2max, and G2 - to apply both predictive equations (actual and from Cureton et al.) to evaluate their validity on estimating VO2max in a Brazilian population sample. Significant differences were observed between VO2max directly identified on IT through gas analysis (50.1±7.1 mL.kg-¹.min-¹) in relation to the results obtained by the predictive equation proposed by Cureton et al. (1995) (44.2±6.5mL.kg-¹.min-¹) with a weak relationship between them (r = 0.21). The relationship between the VO2max on IT and the running velocity on 1600-m as obtained for G1 resulted in the following predictive equation: (VO2max = 0.177*1600Vm(m.min-1) + 8,101). When this new equation was applied on the participants of G2, the predicted VO2max (50.1±7.2mL.kg-¹.min-¹) did not differ from VO2max determined directly on IT (50.1±7.1mL.kg-¹.min-¹) with a high correlation between them (r = 0.81). Thus, it was concluded that the Cureton et al. predictive equation developed with a North Americanpopulation sample as grounding, underestimated the VO2max of physically active young Brazilians. On the other hand, the predictive equation proposed on the present study was considered valid for this purpose through the 1600-m running performance for our participants.

Jeeser Alves de, Almeida; Carmen S. G., Campbell; Emerson, Pardono; Rafael da Costa, Sotero; Guilherme, Magalhães; Herbert Gustavo, Simões.

2010-02-01

260

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Shen, Charles; Schulzrinne, Henning

2008-01-01

 
 
 
 
261

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

Directory of Open Access Journals (Sweden)

Full Text Available COMPENDIO los usos evaluados fueron pastizal, cafetal y bosque secundario (Vereda Villa del Rosario, Aprox. 3º 33' 16â€? Latitud Norte y 76º 36' 01â€? Longitud Oeste, altitud 1.500 a 1.820m., precipitación 960 a 1.050 mm/año, 19.8 a 21.2º C con la metodología TSBF. Se implementaron tres monolitos por uso y cada uno se subdividió en cuatro estratos (hojarasca, 0-10 cm, 10-20 cm, y 20-30 cm, las variables densidad y biomasa por parcela y estrato se examinaron a través de ANOVAS y Post-Anovas. En abundancia la supremacía fue de hormigas (25584 ejemplares, miriápodos (4808 ejemplares y lombrices (1984 ejemplares, la diferencia significativa la marcaron los miriápodos (F=4.84, P=0.014 asociados con bosque y cafetal con sombrío. En biomasa los grupos más importantes fueron miriápodos (701.05 g m-2, 58.71%, lombrices (90.64 g m-2; 7.59%, chisas (27.07 g m-2; 2.26% hor­migas (20.90 g m-2; 1.75% y arañas (15.71 g m-2 ; 1.31%, con diferencias significativas en hormigas (F=4.17, P=0.024 y arañas (F=3.43, P=0.4024; También hubo diferencias estadísticas significativas en la densidad y biomasa de macroinvertebrados y los estratos de los monolitos, los resultados indican que estos organismos expresan en su población y biomasa respuestas ambientales asociadas más con la estructura del agroecosistema que con la variación química, física o microbiológica del hábitat; se recomienda discriminar taxonómicamente los grupos funcionales y ampliar los muestreos a la temporada seca. Palabras clave: uso del suelo, macroinvertebrados edáficos, densidad, abundancia, agroecosistemas, Andes colombianos. ABSTRACT Abundance and biomass of soil macroinvertabrates during the rainy season in three land use systems in the Colombian Andes. Using the TSBF methodology, three land use systems—pastures, coffee plantation, and secondary forest— were evaluated in the rural community of Villa del Rosario, located in the municipality of Cali, Valle del Cauca, Colombia . This community is located at approximately 3º 33' 16 N and 76º 36' 01 W, with an altitude of 1.500-1.820 m above sea level, an annual precipitation of 960-1.050 mm, and temperatures ranging from 19.8 to 21.2º C. Three monoliths were used per land use system, each one subdivided into four strata (fallen leaves and 0-10 cm, 10-20 cm, and 20-30 cm in depth. The variables for density and biomass per plot and stratum were submitted to ANOVA and post-ANOVA comparison. Among macroin­vertebrates found, ants outnumbered the others by far with 25.584 individuals, followed by myriapods with 4808 individuals, and earthworms with 1984. A significant difference was found in the case of myriapods (F=4.84, P=0.014 in association with forest and coffee plantation under shade. In terms of biomass, the most important groups found were myriapods (701.05 g m-2, 58.71%, earthworms (90.64 g m-2, 7.59%, grubs (27.07 g m-2, 2.26%, ants (20.90 g m-2, 1.75%, and spiders (15.71 g m-2, 1.31%. Significant differences were found in the case of ants (F=4.17, P=0.024 and spiders (F=3.43, P=0.4024. Significant statistical differences were also found for density and biomass of macroinvertebrates and monolith strata. Results indicated that the environmental response of these organisms in terms of population and biomass is more associated to agroecosystem structure than to chemical, physical, or microbiological variation of the habitat. Functional groups should be taxonomically differentiated and samplings should be extended to the dry season. Key words: land use, soil macroinvertebrates, density, agroecosystems, Colombian Andes, biomass.

Pardo Luis C

2006-03-01

262

Conversión hidrotérmica subcrítica de residuos orgánicos y biomasa: Mecanismos de reacción / Subcritical hydrothermal conversion of organic wastes and biomass: Reaction pathways  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish La conversión hidrotérmica es un procedimiento que emula el proceso natural de conversión de la materia orgánica en un biocrudo con propiedades físico-químicas similares a las del petróleo. La transformación artificial de biomasa requiere conocer previamente las rutas de reacción y productos prevale [...] ntes. En la conversión de celulosa, el principal componente de la biomasa, se presenta despolimerización por hidrólisis y se obtienen oligosacáridos, los cuales presentan deshidratación y condensación retro-aldol, para transformarse en furfurales y ácidos carboxílicos. Otros componentes de la biomasa como lignina, proteínas y ésteres grasos, presentan rutas de reacción en las que coexisten la hidrólisis y la pirólisis. Dada la presencia de carbohidratos en la biomasa, los principales productos de su conversión hidrotérmica subcrítica y de sus residuos serán análogos a los que presenta la celulosa. Dichas sustancias tienen un valor agregado que supera considerablemente los costos de adquisición de la materia prima. Al representar en un gráfico las relaciones molares O/C, H/C de los principales productos de conversión hidrotérmica de biomasa reportados en la literatura, se evidencia que la trayectoria de evolución para los productos de conversión hacia biocrudos se traslapa con la evolución geológica de los combustibles fósiles. Abstract in english Hydrothermal conversion is a procedure which emulates organic matter’s natural conversion into bio-crude having physical and chemical properties analogous to petroleum. The artificial transformation of biomass requires previous knowledge of the main reaction routes and product availability. The main [...] component of biomass (depolymerisation by hydrolysis) is presented in hydrothermal cellulose conversion, producing oligosaccharides which exhibit dehydration and retro-aldol condensation reactions for transforming into furfurals and carboxylic acids. Other biomass components (such as lignin, proteins, and fat esters) present both hydrolysis and pyrolysis reaction routes. As long as biomass mainly contains carbohydrates, subcritical hydrothermal conversion products and their wastes will be fundamentally analogous to those displaying cellulose. These substances have added-value by far surpassing raw material’s acquisition cost. When the main hydrothermal conversion products’ O/C, H/C molar ratios as reported in literature are plotted, an evolutionary trajectory for conversion products appears to be closely or even overlapped with fossil fuels’ geological evolution.

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

2007-04-01

263

Biosorption of Pb (II) by Agave tequilana Weber (agave azul) biomass / Biosorpción de Pb (II) por biomasa de Agave tequilana Weber (agave azul)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish En este estudio, la biomasa producida de los residuos industriales y el desecho agrícola del Agave tequilana Weber (Agave azul) generados en la producción de tequila, demostró un alto potencial para la remoción de Pb (II) de soluciones acuosas. La capacidad de biosorción de la biomasa de las hojas d [...] e Agave azul fue evaluada en experimentos en lote. Estos experimentos incluyeron perfil de pH, dependencia del tiempo y la determinación de la capacidad de adsorción. Los experimentos de dependencia del tiempo indicaron que la adsorción de los iones de Pb(II) por la biomasa de Agave azul fue dependiente del tiempo. Las isotermas de Freundlich y Langmuir fueron usadas para describir la biosorción del Pb (II) sobre la biomasa de las hojas del Agave azul a 298 K y un pH de 5.0. El coeficiente de correlación para la isoterma de Freundlich fue más alto que el respectivo coeficiente para la isoterma de Langmuir, indicando que solo el modelo de Freundlich describe los datos obtenidos. La máxima capacidad (K F) fue 105.52 10-2 moles/g para Pb (II). La capacidad de adsorción mostrada por la biomasa del Agave azul fue más alta que el valor promedio de los valores reportados en la literatura. Abstract in english In this study, the biomass produced from the industrial residues and agricultural waste of Agave tequilana Weber (Agave azul) generated in the production of tequila, demonstrated a high potential for Pb (II) removal from aqueous solution. The biosorption capacity of Agave azul leaves biomass was eva [...] luated in batch experiments. These experiments included pH profile, time dependence, and the determination of adsorption capacity. Time profile experiments indicated that the adsorption of Pb ions by Agave azul biomass was time-dependent. Freundlich and Langmuir isotherms were used to describe the biosorption of Pb (II) onto the Agave azul leaves biomass at 298 K and pH 5.0. The correlation coefficient for the Freundlich isotherm was much higher than the coefficient for the Langmuir isotherm, indicating that only the Freundlich models fits the data. The maximum capacity (K F) was 105.52 10-2 mole/g for Pb (II). The adsorption capacity showed by Agave azul biomass was higher than the average values reported in the literature.

J, Romero-González; F, Parra-Vargas; I, Cano-Rodríguez; E, Rodríguez; J, Ríos-Arana; R, Fuentes-Hernández; J, Ramírez-Flores.

2007-12-01

264

Structural and thermal studies on Pu(VO3)4  

International Nuclear Information System (INIS)

An hitherto unknown metavanadate of plutonium with composition Pu(VO3)4 was synthesized by heating appropriate amounts of pre-dried PuO2 and V2O5 at 640 deg C for 48 h. The brownish product obtained was characterized by Rietveld refinement of powder XRD data and thermogravimetric analysis. Structural analyses revealed that, Pu(VO3)4 crystallizes in tetragonal (space group: I41/a) lattice with unit cell parameters: a = 8.4582(3) and c = 28.683(2) and Z = 8. The crystal structure of Pu(VO3)4 is isostructural to Th(VO3)4 and Np(VO3)4. TG curve of Pu(VO3)4 did not show any weight change up to 1000 deg C. DTA peaks at 665 and 575 deg C correspond to the melting and crystallization of Pu(VO3)4. (author)

265

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

Science.gov (United States)

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

Villano, Matt

2006-01-01

266

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

Science.gov (United States)

Nitrogen-doped graphene sheets (NGS), synthesized by annealing graphite oxide (GO) with urea at 700-1050 °C, were studied as positive electrodes in a vanadium redox flow battery. The NGS, in particular annealed at 900 °C, exhibited excellent catalytic performance in terms of electron transfer (ET) resistance (4.74 ± 0.51 and 7.27 ± 0.42 ? for the anodic process and cathodic process, respectively) and reversibility (?E = 100 mV, Ipa/Ipc = 1.38 at a scan rate of 50 mV s(-1)). Detailed research confirms that not the nitrogen doping level but the nitrogen type in the graphene sheets determines the catalytic activity. Among four types of nitrogen species doped into the graphene lattice including pyridinic-N, pyrrolic-N, quaternary nitrogen, and oxidic-N, quaternary nitrogen is verified as a catalytic active center for the [VO](2+)/[VO2](+) couple reaction. A mechanism is proposed to explain the electrocatalytic performance of NGS for the [VO](2+)/[VO2](+) couple reaction. The possible formation of a N-V transitional bonding state, which facilitates the ET between the outer electrode and reactant ions, is a key step for its high catalytic activity. PMID:23647240

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

2013-06-25

267

E-LEARNING SOLUTIONS IN EDUCATION OF PEDAGOGIC EMPLOYEES / E-learningové riešenia vo vzdelávaní pedagogických zamestnancov  

Directory of Open Access Journals (Sweden)

Full Text Available According to the requirements on qualitative forms and methods of education, Methodical-pedagogical centre, has prepared a project supporting teaching with use of modern educaton methods with sponzorship from ESF For providing such an extensive project the Methodical-pedagogical centre used e-learning environment. The first part of article emphasizes the importance of teachers education in the new socio-economical conditions. It defines the needs of teachers in the field of using ICT during the education process. It describes forms and methods suitable for gaining new competencies. The second part of the article gives us the information abouth e-learning portal of the project „Functional literacy of teachers in information technologies - use of ICT in subjects". The modules are using the different possibilities of MOODLE interface. Author evaluates the interest of teachers for e-learning and the feedback from lectu-trers. The third part of the article presents first experience of using videoconference in the field of education of teachers, on example of a conference aimed to use of ICT in the work of elementary and high school teachers (in the preparation for teaching and also in the teaching process itself.Na základe potreby zvyšovania k?ú?ových kompetencií pedagogických zamestnancov bol s finan?nou podporou ESF pripravený projekt na podporu vyu?ovania s využitím moderných vyu?ovacích metód. Na zabezpe?enie rozsiahleho projektu v oblasti využívania informa?ných technológií a na zvýšenie efektívnosti vzdelávania pedagogických zamestnancov využilo Metodicko-pedagogické centrum v Tren?íne e-learningové prostredie. Príspevok v prvej ?asti poukazuje na význam vzdelávania u?ite?ov v nových spolo?ensko-eko-nomických podmienkach. Definuje potreby u?ite?ov v oblasti využívania IKT na vyu?ovaní a predstavuje formy a metódy vhodné na získanie nových kompetencií. V druhej ?asti príspevku je predstavený e-learningový portál projektu Funk?ná gramotnos? u?ite?ov v informa?ných technológiách - využitie IKT vo vyu?ovacích predmetoch. Jednotlivé vzdelávacie moduly rozli?nou mierou využívajú možnosti prostredia MOODLE. Autor vyhodnocuje záujem pedagógov o e-learningové vzdelávanie a skúsenosti lektorov zo vzdelávania. V tretej ?asti príspevku sú predstavené prvé skúsenosti využitia videokonferencie v oblasti vzdelávania pedagógov na príklade konferencie zameranej na využívanie informa?ných technológií v práci pedagógov základných a stredných škôl - v príprave na vyu?ovanie i vo vlastnom vyu?ovacom procese.

Jakubeková Miroslava

2008-06-01

268

Hydrothermal synthesis, dimension evolution and luminescence properties of tetragonal LaVO4:Ln (Ln = Eu3+, Dy3+, Sm3+) nanocrystals.  

Science.gov (United States)

Well-defined 1D and 3D t-LaVO(4):Ln (Ln = Eu(3+), Dy(3+), Sm(3+)) nanocrystals with regular and uniform shapes were synthesized through a simple hydrothermal route assisted by disodium ethylenediaminetetraacetic acid (Na(2)EDTA). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), as well as kinetic decay curves were employed to characterize the samples. The results show that the reaction time, pH value of the initial solution, and Na(2)EDTA/La(3+) molar ratio all have an important influence on the dimension and shapes of the final products. By introducing the "splitting mechanism" to the dimension and morphology evolution process from one-dimensional (1D) to three-dimensional (3D) t-LaVO(4) crystals, the nucleation and crystal growth processes were well demonstrated. The Ln(3+) ions doped t-LaVO(4) samples exhibit respective bright red, blue-white and orange luminescence of Eu(3+), Dy(3+), and Sm(3+) under ultraviolet excitation, and have potential application in the fields of colour display, UV laser and biomedicine. The results not only expand the knowledge of the properties of lanthanide orthovanadates luminescence, but also contribute to the principles of the crystal growth and dimension transition of this kind of inorganic material. PMID:21927748

He, Fei; Yang, Piaoping; Wang, Dong; Niu, Na; Gai, Shili; Li, Xingbo; Zhang, Milin

2011-11-01

269

Biomasa de rotíferos de dos embalses con diferentes estados tróficos (Antioquia, Colombia) y su relación con algunas variables limnológicas / Rotifer biomass of two reservoirs with different trophic states (Antioquia, Colombia) and its relationship with some limnological variables  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Se evaluó la variación de la biomasa de rotíferos en los ejes longitudinal y vertical de la zona fótica de los embalses La Fe y Riogrande II (Antioquia), Colombia, con diferentes estados tróficos, durante los periodos de alta y baja precipitación. Además, se analizó su relación con las variables tem [...] peratura, oxígeno disuelto, pH, transparencia, nutrientes y con la biomasa fitoplanctónica. La biomasa de rotíferos fue dominada por Asplanchna girodi De Geurne 1888, en los dos embalses y fue significativamente mayor en el embalse de menor trofía. Aunque la biomasa de rotíferos no mostró un gradiente longitudinal significativo, sí presentó zonación vertical dentro de la zona fótica, con mayor biomasa en el 10 y 1% de incidencia lumínica. Los patrones de variación de la biomasa total de rotíferos y de las especies dominantes estuvieron determinados principalmente por el ingreso de sólidos suspendidos en el embalse de mayor trofía y por la biomasa y la densidad del fitoplancton en el embalse con menos nutrientes. A diferencia de lo esperado, la biomasa de los rotíferos no fue favorecida por condiciones de mayor estado trófico, ya que el factor preponderante sobre la expresión de biomasa fue la calidad de los recursos alimenticios en cada embalse. Abstract in english Rotifers biomass was evaluated across longitudinal and vertical axes of the photic zone in the La Fe y Riogrande II reservoirs (Antioquia), Colombia, with different trophic states during periods of high and low precipitation. IN addition, its relationship with temperature, dissolved oxygen, pH, tran [...] sparency, nutrient availability, and phytoplankton biomass was analyzed. In both reservoirs, rotifer biomass was dominated by Asplanchna girodi De Geurne, 1888, and it was significantly higher in the reservoir with a lower trophic state. Even though rotifers biomass did not exhibit a longitudinal gradient, a vertical zonation in the photic zone was documented, with the greatest biomass at 10% and 1% of light intensity. Patterns of variation in total rotifer biomass and in dominant species biomass appear to be determined primarily by the entry of suspended solids into the reservoir with the higher trophic state, and by phytoplankton biomass and density in the reservoir with lower nutrient levels. Contrary to expectations, rotifer biomass was not favored by increasing trophic state. The most important factor determining rotifer biomass was the quality of food resources in each reservoir.

Silvia L, Villabona-González; Robinson F, Buitrago-Amariles; John J, Ramírez-Restrepo; Jaime A, Palacio-Baena.

2014-12-01

270

VO Activities at the Harvard-Smithsonian CfA  

Science.gov (United States)

This paper summarizes the VO activities at the Harvard-Smithsonian Center for Astrophysics (CfA). Cfa has expertise covering virtually all branches of observational astronomy and of astrophysical research, as well as data and information management (the Chandra X-ray Center - CXC, and the Astrophysical Data System - ADS). At CfA, we have a leading role in the US National Virtual Observatory (NVO) team for the development of the VO Data Model(s), in collaboration with the European Astrophysical Virtual Observatory (AVO). To this end, we are validating our design with a local prototype, which will federate the CfA data archives, starting with the X-ray (Chandra) and optical (Telescope Data Center - TDC) archives.

Fabbiano, Giuseppina

271

VoIP over WMN: Effect of packet aggregation  

Directory of Open Access Journals (Sweden)

Full Text Available VoIP services are getting more and more popular day by day. In order to meet the users demand for such services irrespective of users location requires wide area wireless coverage .To this extent,wireless mesh networks have been considered as practical and inexpensive solution .In order to improve the performance of VoIP services, techniques like packet aggregation are done . This paper focuses on finding the effect of packet aggregation on various parameters like aggregation delay, end to end delay and MOS etc. Results obtained through simulations done on Qualnet Simulator concludes that packet aggregation is justified upto a certain extent only as after that most of the users get dissatisfied.

Khyati Marwah,

2011-06-01

272

Epitaxial growth of VO2 by periodic annealing  

International Nuclear Information System (INIS)

We report the growth of ultrathin VO2 films on rutile TiO2 (001) substrates via reactive molecular-beam epitaxy. The films were formed by the cyclical deposition of amorphous vanadium and its subsequent oxidation and transformation to VO2 via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3?nm, where a resistance change ?R/R of 25 was measured. Low angle annular dark field scanning transmission electron microscopy was used in conjunction with electron energy loss spectroscopy to study the film/substrate interface and revealed the vanadium to be tetravalent and the titanium interdiffusion to be limited to 1.6?nm

273

Federating Catalogs and Interfacing Them with Archives: A VO Prototype  

Science.gov (United States)

A common scientific requirement is to perform a joint query on two or more remote catalogs, then use the resulting combined catalog as input to query an archive or catalog. We have developed techniques which enable the routine federation of several of the largest astrometric and photometric catalogs from either in-house or remote copies, and use this federated output to query the several archives of spectral and imaging data which we either manage or maintain local copies of. Allowing the federation of arbitrary sections of large catalogs, with user defined match criteria; and then allowing this result to be used to query several large archives of spectral and imaging data (also subject to user constraints) is a key goal of all VO projects. The problems we have solved in developing our methods will also have to be addressed by any VO project which delivers similar capabilities.

Mink, D. J.; Kurtz, M. J.

274

Epitaxial growth of VO{sub 2} by periodic annealing  

Energy Technology Data Exchange (ETDEWEB)

We report the growth of ultrathin VO{sub 2} films on rutile TiO{sub 2} (001) substrates via reactive molecular-beam epitaxy. The films were formed by the cyclical deposition of amorphous vanadium and its subsequent oxidation and transformation to VO{sub 2} via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3?nm, where a resistance change ?R/R of 25 was measured. Low angle annular dark field scanning transmission electron microscopy was used in conjunction with electron energy loss spectroscopy to study the film/substrate interface and revealed the vanadium to be tetravalent and the titanium interdiffusion to be limited to 1.6?nm.

Tashman, J. W.; Paik, H.; Merz, T. A. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Lee, J. H. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Moyer, J. A.; Schiffer, P. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Misra, R. [Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Mundy, J. A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Spila, T. [Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Schubert, J. [Peter Grünberg Institute, PGI 9-IT, JARA-FIT, Research Centre Jülich, D-52425 Jülich (Germany); Muller, D. A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States); Schlom, D. G., E-mail: schlom@cornell.edu [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States)

2014-02-10

275

Gate-tunable gigantic lattice deformation in VO2  

Science.gov (United States)

We examined the impact of electric field on crystal lattice of vanadium dioxide (VO2) in a field-effect transistor geometry by in-situ synchrotron x-ray diffraction measurements. Whereas the c-axis lattice parameter of VO2 decreases through the thermally induced insulator-to-metal phase transition, the gate-induced metallization was found to result in a significant increase of the c-axis length by almost 1% from that of the thermally stabilized insulating state. We also found that this gate-induced gigantic lattice deformation occurs even at the thermally stabilized metallic state, enabling dynamic control of c-axis lattice parameter by more than 1% at room temperature.

Okuyama, D.; Nakano, M.; Takeshita, S.; Ohsumi, H.; Tardif, S.; Shibuya, K.; Hatano, T.; Yumoto, H.; Koyama, T.; Ohashi, H.; Takata, M.; Kawasaki, M.; Arima, T.; Tokura, Y.; Iwasa, Y.

2014-01-01

276

Gate-tunable gigantic lattice deformation in VO2  

International Nuclear Information System (INIS)

We examined the impact of electric field on crystal lattice of vanadium dioxide (VO2) in a field-effect transistor geometry by in-situ synchrotron x-ray diffraction measurements. Whereas the c-axis lattice parameter of VO2 decreases through the thermally induced insulator-to-metal phase transition, the gate-induced metallization was found to result in a significant increase of the c-axis length by almost 1% from that of the thermally stabilized insulating state. We also found that this gate-induced gigantic lattice deformation occurs even at the thermally stabilized metallic state, enabling dynamic control of c-axis lattice parameter by more than 1% at room temperature

277

Preparation of VO2 nanowires and their electric characterization  

International Nuclear Information System (INIS)

Large-scale VO2 nanowires have been synthesized by two-step method. First, we have been obtained (NH4)0.5V2O5 nanowire precursors by hydrothermal treatment of ammonium metavanadate solution at 170 deg. C. Secondly, the precursors have been sealed in quartz tube in vacuum and annealed to form VO2 nanowires at 570 deg. C. Scanning electron microscope and transmission electron microscope analysis show that the nanowires have self-assembling nanostructure with the diameter of about 80-200 nm, length up to125 ?m. Electrical transport measurements show that it is semiconductor with conduction activate energy of 0.128 eV. A metal-semiconductor transition can be observed around 341 K

278

Structural and physical properties of BiVO3  

International Nuclear Information System (INIS)

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

279

VO2 thermochromic smart window for energy savings and generation  

Science.gov (United States)

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

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

2013-10-01

280

PRELIMINARY ANALYSIS OF BIOMASS POTENTIALLY USEFUL FOR PRODUCING BIODIESEL / ANALISIS PRELIMINAR DE BIOMASA POTENCIALMENTE ÚTIL PARA PRODUCIR BIODIESEL  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish Considerando que el biodiesel se está convirtiendo en una solución viable para algunos problemas energéticos y medioambientales, la investigación de materias primas para su producción es un tema de creciente interés. Este estudio presenta los resultados de una investigación dedicada al análisis prel [...] iminar de varias especies vegetales (biomasa), potencialmente útiles para producir biodiesel. La zona de bioprospección es una región de la costa pacifica colombiana. Las especies promisorias recolectadas fueron sometidas a diferentes pruebas normalizadas ASTM para definir propiedades que faciliten su evaluación. Algunas de las especies fueron sometidas a un proceso de transesterificación. Adicionalmente, se realiza una comparación entre las propiedades termo-físicas de los biodiesel y las propiedades del diesel comercial. Las pruebas de rendimiento de estos biocombustibles en los motores de encendido por compresión, particularmente la eficiencia, el consumo y la potencia a diferentes RPM del motor, se presentan en este trabajo. Abstract in english Given that biodiesel is emerging as a viable solution for some energy and environmental problems, research on raw materials appropriate for its production is a matter of growing interest. In this study we present the results of research devoted to preliminary analysis on several vegetable (biomass) [...] species potentially useful for producing biodiesel. The bioprospection zone is a region on the Colombian Pacific coast. The candidate species collected underwent different standardized ASTM tests in order for us to define properties that facilitate their evaluation. Some of the species underwent a transesterification process. Comparisons between the thermo-physical properties of the biofuels obtained and the properties of commercial diesel were carried out. Also, performance tests for these biofuels were conducted in compression ignition engines, particularly evaluating efficiency, fuel consumption, and potency at different RPMs.

GERARDO, CABRERA CIFUENTES; JUAN CARLOS, BURBANO JARAMILLO; JOSÉ ISIDRO, GARCIA MELO.

2011-12-01

 
 
 
 
281

Biomasa, rendimiento, eficiencia en el uso del agua y de la radiación solar del agrosistema girasol-frijol  

Directory of Open Access Journals (Sweden)

Full Text Available El estudio se realizó durante el verano de 2002 Los tratamientos consistieron en la siembra en unicultivo y combinación de frijol Canario 107, Bayomex (hábito de crecimiento determinado, Michoacán (hábito de crecimiento indeterminado y girasol cv. Victoria. La siembra se realizó el 25 de mayo de 2002 a la densidad de población de 4.2 y 8.3 plantas m-2 de girasol y frijol, respectivamente, en un suelo de textura arcillosa, con un pH de 7.8 y se fertilizó con 100-100-00 de NPK. El diseño experimental fue bloques al azar con cuatro repeticiones. El sistema de siembra no afectó la fenología, el requerimiento térmico y la evapotranspiración de ambos cultivos. Las unidades calor (UC y la evapotranspiración (ETc de los cultivos de la siembra a la madurez fisiológica fueron 1521 UC y 279.6 mm para el cv. Victoria, 658 UC y 201.3 mm para Canario 107, 811 UC y 213.7 mm para Bayomex y 1041 UC y 241.7 mm para Michoacán. El agrosistema combinado de girasol y frijol fue más eficiente en el uso de los insumos para la producción agrícola. La combinación de girasol Victoria y frijol Michoacán mostró la eficiencia en el uso del agua (EUA y eficiencia en el uso de la radiación (EUR más alta y, en consecuencia, una mayor producción de biomasa y rendimiento. El uso equivalente de la tierra (UET para el rendimiento de semilla obtenido con la combinación de Victoria más Canario 107, Victoria más Michoacán y Victoria más Bayomex fue de 1.6, 1.9 y 3.0, respectivamente, y muestra una ventaja en el rendimiento de los cultivos combinados sobre los unicultivos de 60, 90 y 200%, respectivamente.

Edgar J. Morales-Rosales

2006-01-01

282

Implementation of Cloud Computing into VoIP  

Directory of Open Access Journals (Sweden)

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

Floriana GEREA

2012-08-01

283

Lightweight security mechanism for PSTN-VoIP cooperation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we describe a new, lightweight security mechanism for PSTN-VoIP cooperation that is based on two information hiding techniques: digital watermarking and steganography. Proposed scheme is especially suitable for PSTN-IP-PSTN (toll-by-passing) scenario which nowadays is very popular application of IP Telephony systems. With the use of this mechanism we authenticate end-to-end transmitted voice between PSTN users. Additionally we improve IP part traffic security (...

Mazurczyk, Wojciech; Kotulski, Zbigniew

2006-01-01

284

Integrating VoIP systems with computer applictions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This diploma thesis discusses the interconnection of two systems that were strictly separated until emergence of recent technologies which enable coexis- tence of voice and data in the same network. These technologies bring two completely separate worlds of telephony networks and data networks closer together and they go under a common name of Voice over IP technologies or simply VoIP. This most often results in computer applications which use call control mechanisms and...

Tis?ler, Marko

2010-01-01

285

VO2: A Novel View from Band Theory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New calculations for vanadium dioxide, one of the most controversely discussed materials for decades, reveal that band theory as based on density functional theory is well capable of correctly describing the electronic and magnetic properties of the metallic as well as both the insulating M1 and M2 phases. Considerable progress in the understanding of the physics of VO2 is achieved by the use of the recently developed hybrid functionals, which include part of the electron-el...

Eyert, V.

2011-01-01

286

Novas arquiteturas Web para aplicações VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The appearance of cheap audio and video devices and the fact that they are already included in almost all computers, added to the availability of higher speed Internet connections, have increased the interest in the creation of a system capable of establishing calls in this network (VoIP). Lately, the number of applications that are being migrated from desktop to browsers have increased and so, Google decided to create a technology proposal to allow browsers native access to micro...

Silva, Andre? Manuel Rodrigues Da

2013-01-01

287

Structure of dibismuth vanadate Bi2VO5.5  

International Nuclear Information System (INIS)

Bi2VO5.5, Mr = 556.9, orthorhombic, Aba2, A = 5.598 (2), b = 15.292 (9), c = 5.532 (2) A, V = 473.6 A3, Z = 4, Dm = 7.6, Dx = 7.808 Mg m-3, ?(Mo K?) = 0.71069 A, ? = 75.75 mm- 1, F(000) = 932, T = 293 K, R = 0.038 for 396 unique observed reflections. Owing to a very short Bi-O bond (1.89 A), the structure may be described by alternating Bi2O2.75 0.5+ layers of very irregular corner-sharing BiO4 tetrahedra and by VO2.75 0.5- layers of distorted corner-sharing VO6 octahedra. This structure is slightly different from that of well known oxides of the Aurivillius family and especially of Bi2XO6 compounds (X = Mo, W) containing Bi2O22+ layers of edge-sharing BiO4 square pyramids. (orig.)

288

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish La generación de ecuaciones alométricas es importante para determinar la biomasa y el carbono en las especies arbóreas. Esta información es útil en los estudios de cambio climático. En el presente estudio se generaron ecuaciones alométricas para dos especies de importancia ecológica en el bosque mes [...] ófilo de montaña: Clethra mexicana DC y Alnus arguta (Schltdl) Spach. Las ecuaciones que se determinaron son de la forma Y= bXk; donde: Y= contenido de biomasa o de carbono (kg); y X= diámetro normal (DN) en centímetros. Para estimar los valores b y k del modelo para cada especie, se realizó un muestreo de quince árboles de Clethra mexicana y 22 de Alnus arguta. En Clethra mexicana el mayor porcentaje de biomasa 45.2 % se encontró en el fuste incluido el tocón, mientras que en las ramas y el follaje estaba 36.3% y 18.6%, respectivamente. Con la biomasa y el DN de los árboles se determinaron los parámetros b y k del modelo propuesto (B= 0.4632 DN1.8168, R²= 0.946). Para Alnus arguta el mayor porcentaje de biomasa (60.6%), se encontró en el fuste incluido el tocón, mientras que en las ramas y el follaje presentó 27.4 y 12%, respectivamente. Al igual que el caso anterior con la biomasa y el DN, se obtuvieron los parámetros b y k del modelo propuesto (B= 0.1649 DN2.2755, R²= 0.968). Después de analizar el contenido de carbono en las muestra de cada especie, se ajustaron las ecuaciones para Clethra mexicana C= 22.49DN1.8168, con R²= 0.946, mientras que para Alnus arguta C= 0.0809DN2.2782 con R²= 0.968. Abstract in english The generation of allometric equations is important to determine biomass and carbon in tree species. This information is useful in climate change studies. In this paper, allometric equations were generated for two species of ecological importance in the cloud forest: Clethra mexicana DC and Alnus ar [...] guta (Schltdl) Spach. Equations determined are of the form Y= bXk; where: Y= biomass or carbon content (kg); and X= normal diameter (ND) in centimeters. To estimate model values of b and k for each species, a sampling was performed in fifteen Clethra mexicana and 22 of Alnus arguta trees. In Clethra mexicana the highest percentage of biomass 45.2% was found in the trunk including the stump, while branches and foliage had 36.3% and 18.6% respectively. With the biomass and ND of the tress, b and k parameters were determined from the proposed model (B= 0.4632 DN1.8168, R²= 0.946). For Alnus arguta the highest percentage of biomass (60.6%) was found in the trunk including the stump, while branches and foliage had 27.4 and 12% respectively. Like the previous case with biomass and ND, b and k parameters were obtained from the proposed model (B= 0.1649 DN2.2755, R²= 0.968). After analyzing carbon content in each species samples, equations were adjusted for Clethra mexicana C= 22.49DN1.8168, with R²= 0.946, whereas for Alnus arguta C= 0.0809DN2.2782 with R² = 0.968.

Miguel, Acosta Mireles; Fernando, Carrillo Anzures; Raúl Gilberto, Gómez Villegas.

2011-08-01

289

Producción de biomasa de Artemia franciscana Kellogg 1906 utilizando diferentes dietas / Biomass production of Artemia franciscana Kellogg 1906 using different diets  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish Se realizó el cultivo semiintensivo de Artemia franciscana, cepa Perú, utilizando diferentes dietas en base a microalgas e insumos alimenticios que forman parte de algunos ingredientes que se utilizan para preparar alimento formulado de peces y crustáceos, con el fin de determinar la factibilidad de [...] l uso de estos para la obtención de biomasa de adultos. El estudio se ejecutó en base a un diseño experimental completamente aleatorio con 7 tratamientos y 3 réplicas cada uno, aplicándose a los datos obtenidos un Análisis de Varianza de una vía (ANOVA) y la prueba de Tukey para establecer diferencias significativas entre los tratamientos. Los resultados del análisis próximal de las dietas, mostraron que la harina de soya presentó la cantidad de proteínas requerida por A. franciscana durante su crecimiento (34.33 %), igualmente con esta dieta se obtuvo la mejor tasa de crecimiento (0.19), biomasa más alta (113.33 g) y el mejor Factor de Conversión Alimenticia (1.4). Así mismo la biomasa de A. franciscana producida con harina de soya, presentó un nivel de proteínas adecuado para la maduración de reproductores de crustáceos (53.38 %). Abstract in english Artemia franciscana, Peru strain, was cultured under different diets-based in microalgae and nutritious inputs with the aim to determine the feasibility to produce adult Artemia biomass. A completely randomized design experiment was carried out, with seven treatments and three replications each one. [...] One way variance analysis (ANOVA) and the Turkey test were used to analyze the data to establish significant differences among treatments. The results of biochemical analysis showed that soya bean diet fulfilled the protein content needed for a proper growth of A. fransiscana. This diet also showed the best growth rate (0.19), highest biomass production (113.13 g), best food conversion ratio (1.4) and a protein content suited for crustacean broodstock maturation (53.38%).

Rosario, Cisneros; Enrique, Vinatea.

2009-12-01

290

Relative Aerial Biomass Yield of Intercroped Alfalfa with Winter Forage Cereals Rendimiento Relativo de Biomasa Aérea en Intercultivos de Alfalfa con Cereales Forrajeros de Invierno  

Directory of Open Access Journals (Sweden)

Full Text Available In the tropical regions of the world, intercropping is mostly associated with food grain production, whereas it is receiving increased attention in temperate regions as a means of efficient forage production. The aim of this work was to determine the relative yield of aerial biomass in alfalfa or lucerne (Medicago sativa L. and winter forage cereals intercrops. These were done in eight systems resulting from the combination of species sown at different dates. The biomass was measured in three situations: alfalfa and cereal sole-crop and alfalfa-cereal intercrops, the relative biomass yields were calculated by the relative yield index (RYI. The field experiment was conducted as a bifactorial array in a randomized complete block design of two replicates. The alfalfa-cereal intercrops provided RYI values ranging from 0.71 to 0.83. This showed that it is possible to produce, in the same area, between 71 and 83% of the biomass that both crops would produce in separate ones.En las regiones tropicales del mundo, el intercultivo está asociado con la producción de granos para la alimentación, mientras que en áreas templadas recibe mayor atención como medio de producción eficiente de forraje. El objetivo de este experimento fue determinar el rendimiento relativo de biomasa aérea en intercultivos de alfalfa (Medicago sativa L. y cereales forrajeros de invierno. Se establecieron ocho sistemas producto de la combinación con especies de cereales con distintas fechas de siembra. Las mediciones de biomasa se realizaron en tres situaciones: monocultivo de alfalfa, monocultivo de cereales e intercultivo de alfalfa-cereal, calculándose el rendimiento relativo del intercultivo (RRI. Se empleó un diseño con arreglo bifactorial y dos repeticiones en bloques completos al azar. Los intercultivos de alfalfa-cereal generaron valores de RRI entre 0,71 y 0,83, lo que indicó que en una misma superficie es posible producir entre el 71 y 83% de la biomasa que ambos cultivos producirían en superficies separadas.

Telmo Pereyra

2008-09-01

291

Dioxodichlorovanadate [VO2Cl2]-; preparation, vibrational spectrum, and crystal structure of [Ph3PMe][VO2Cl2  

International Nuclear Information System (INIS)

The title compound was obtained from VO2Cl and [Ph3PMe]Cl in CH2Cl2 solution in form of orange crystals. Its crystal structure was determined with X-ray diffraction data and was refined to a residual index of R = 5.6% (2124 observed, independent reflexions). [Ph3PMe][VO2Cl2] crystallizes in the rhombic space group P212121 = D24 with four formula units in the unit cell. The low symmetry of the space group causes chirality of the cation. The complex anion is in good agreement with Csub(2v) symmetry; it is isoelectronic with CrO2Cl2. The vibrational spectrum (IR, Raman) was recorded and assigned. (author)

292

Electrospun carbon nanofibres as electrode materials toward VO2+/VO2+ redox couple for vanadium flow battery  

Science.gov (United States)

Polyacrylonitrile (PAN) carbon nanofibres with diameters of 100-200 nm have been developed by electrospinning and subsequent carbonization process. The composition, structure, electrical conductivity, and electrochemical properties of the carbon nanofibres as electrode materials for vanadium flow battery (VFB) have been characterized. It is found that with the increasing of carbonization temperature, the electrochemical activity of carbon nanofibres toward VO2+/VO2+ redox couple is enhanced greatly. Particularly, the 1000 °C-carbonized nanofibres show excellent performance. The good behavior of the nanofibres carbonized at high temperature may attribute to the conversion of fibers inner-structure and the improvement of electrical conductivity. Compared with the traditional carbon fibers (TCFs), electrospun carbon nanofibres (ECNFs) carbonized at temperature of 1000 °C exhibit higher activity toward the vanadium reaction, presenting considerable potential for electrode application in VFB.

Wei, Guanjie; Liu, Jianguo; Zhao, Huan; Yan, Chuanwei

2013-11-01

293

Building a VO-compliant Radio Astronomical DAta Model for Single-dish radio telescopes (RADAMS)  

CERN Document Server

The Virtual Observatory (VO) is becoming the de-facto standard for astronomical data publication. However, the number of radio astronomical archives is still low in general, and even lower is the number of radio astronomical data available through the VO. In order to facilitate the building of new radio astronomical archives, easing at the same time their interoperability with VO framework, we have developed a VO-compliant data model which provides interoperable data semantics for radio data. That model, which we call the Radio Astronomical DAta Model for Single-dish (RADAMS) has been built using standards of (and recommendations from) the International Virtual Observatory Alliance (IVOA). This article describes the RADAMS and its components, including archived entities and their relationships to VO metadata. We show that by using IVOA principles and concepts, the effort needed for both the development of the archives and their VO compatibility has been lowered, and the joint development of two radio astronom...

Santander-Vela, J D; Leon, S; Espigares, V; Ruiz, J E; Verdes-Montenegro, L; Solano, E

2012-01-01

294

A importância do limiar anaeróbio e do consumo máximo de oxigênio (VO2 máx.) em jogadores de futebol / The importance of the anaerobic threshold and maximum oxygen uptake (VO2 PEAK) for soccer players  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo deste estudo foi fazer uma abordagem sobre a importância do limiar anaeróbio (LA) e o consumo máximo de oxigênio (VO2máx.) em jogadores de futebol e comparar os resultados encontrados em nossos futebolistas com os da literatura especializada. Foram avaliados 18 jogadores de futebol profis [...] sional, com média de idade de 24 ± 4 anos, peso de 72,5 ± 5,9kg; estatura de 176,5 ± 7,0cm e superfície corpórea de 1,91 ± 0,15m². Todos os atletas foram avaliados após um período de dois meses de treinamentos. Os futebolistas foram submetidos a teste máximo em esteira ergométrica, utilizando-se protocolo escalonado e contínuo. A resposta de freqüência cardíaca (FC) foi registrada por meio de um eletrocardiógrafo (HeartWare) de 12 derivações simultâneas e, a pressão arterial (PA), por meio de método auscultatório. 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 avaliados por método espirométrico computadorizado respiração-a-respiração (MedGraphics Corporation [MGC]). Os seguintes resultados foram verificados: no (LA): [FC = 173,6 ± 8,6bpm; VO2 = 55,78 ± 5,93ml.kg.-1.min-1; velocidade = 14,6 ± 1,0km.h-1]; no exercício máximo [FC = 189,5 ± 11,4bpm; V E = 134,1 ± 15,9L.min-1; VO2máx. = 63,75 ± 4,93ml.kg.-1.min-1; velocidade = 17,8 ± 1,0km.h-1; Borg = 18,3 ± 1,3 pontos]. Concluindo: Os resultados, comparados com os da literatura especializada na modalidade futebol, demonstraram que os índices de LA e VO2máx. foram semelhantes e, até mesmo, superiores a vários de estudos publicados sobre essas duas variáveis em jogadores de futebol profissional. Entretanto, considerando as posições dos jogadores, não há um consenso definido sobre os índices mais adequados de LA e VO2máx. em futebolistas, mas, sim, sugestões. Abstract in english The aim of this study was to make an approach on the importance of the anaerobic threshold (AT) and the peak oxygen uptake in soccer players, and compare the results found in players to those existing in the specialized literature. An evaluation was made in 18 professional soccer players aged 24 ± 4 [...] ; weight 72.5 ± 5.9 kg; height 176.5 ± 7.0 cm, and body surface 1.91 ± 0.15 m². Every athlete was evaluated after a 2 month training period. The soccer players were submitted to a maximum exercise test on treadmill, using incremental continuous protocol. The heart rate (HR) was recorded by means of an electrocardiograph (HeartWare) with 12 simultaneous leads and the arterial blood pressure (BP) by auscultation method. The pulmonary ventilation (V E), the oxygen uptake (VO2), the carbon dioxide production (VCO2) and the respiratory exchange rate (RER) were evaluated by means of the breath-by-breath spirometric computerized method (MedGraphics Corporation-MGC). The following results were verified in the AT: HR = 173.6 ± 8.6 bpm; VO2 = 55.78 ± 5.93 mlO2.kg-1.min-1; running velocity = 14.6 ± 1.0 km.h-1; maximum exercise: HR = 189.5 ± 11.4 bpm; V E = 134.1 ± 15.9 L.min-1; VO2 peak = 63.75 ± 4.93 mlO2.kg-1.min-1; maximum velocity = 17.8 ± 1.0 km.h-1; Borg scale = 18.3 ± 1.3 points. In conclusion, the results, when compared to those of specialized literature, proved the rate of AT and VO2 peak to be similar and even superior to several results published about such two variables in professional soccer players. Considering, however, the players' position, there is no definite consensus on the most adequate AT rates and VO2 peak in soccer players, but only suggestions.

Paulo Roberto Santos, Silva; Angela, Romano; Alberto Azevedo Alves, Teixeira; Ana Maria, Visconti; Carla Dal Maso Nunes, Roxo; Gilberto Silva, Machado; José Roberto Rivelino, Vidal; Luís Antonio, Inarra.

1999-12-01

295

Evaluación de dos métodos para la estimación de biomasa arbórea a través de datos LANDSAT TM en Jusnajab La Laguna, Chiapas, México: estudio de caso  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Se evaluaron dos métodos para estimar biomasa arbórea con apoyo en sensores remotos (LANDSATTM). El primer método se realizó con base en una clasificación supervisada multiespectral con seis bandas Se utilizaron tipos de vegetación identificados a partir de la composición de biomasa de los géneros d [...] ominantes y de la altura promedio estimada del dosel habiéndose distinguido ocho clases de vegetación. Se obtuvo una biomasa total de 1 073 x 10³t (902 x 10³t a 1220 x 10³t). En el segundo método se utilizaron índices diferenciados de vegetación (NDVI) de las bandas TM4/TM3; TM4/TM5 y TM4/TM7. Se aplicó un modelo de regresión que relaciona la biomasa promedio con los valores digitales (VD) de los NDVI. El modelo exponencial fue el de mejor ajuste para los tres NDVI con una p ? 0.01 Los valores de los NVDI fueron TM4/TM3: R²=0.611; TM4/TM5: R²=0.671 y TM4/TM7: R²=0.676. La biomasa total estimada con cada NDVI fue de 1 164 x 10³t (490 x 10³t a 2 409 x 10³) para TM4/TM3; de 515 x 10³1 (331 x 10³t a 757 x 10³t) para TM4/TM5 y de 726 x 10ª t (398 x 10³1 a 1 210 x 10³1) para TM4/TM7. El resultado de la biomasa total calculada por el método de clasificación multiespectral, comparado con los valores estimados por el método de ordenamiento exponencial, mostró mayor similitud con el valor máximo del NDVI que relaciona las bandas TM4/TM7 (de mayor ajuste estadístico) y con el valor promedio del NDVI TM4/TM3 (de menor ajuste estadístico). Utilizando el NDVI TM4/TM5, todos los valores de biomasa resultaron más bajos. De este estudio se concluye que es posible asociar razonablemente la biomasa de vegetación arbolada de pino-encino y reservorios de carbono con los índices de vegetación A través del uso de sensores remotos se podrían predecir cambios de biomasa en escalas temporales y espaciales. Abstract in english Two approaches to estimate arboreal biomass with remote sensing (LANDSAT TM) are evaluated In the first approach a multi-spectral supervised classification with six bands was applied The classification of the vegetation types is based on biomass composition of the dominant tree species and canopy he [...] ight. Eight vegetation types could be distinguished. According to this approach the total tree biomass amounted to 1 073 x 10³ t (902 to 1 220 x 10³t). In the second approach a Normal Differentiated Vegetation Index (NDVI) of the band combinations TM4/TM3, TM4/TM5 and TM4/TM7 was used, A regression equation was developed to relate arboreal biomass with NDVI. Using these equations, the total biomass was estimated at 1 164 x 10³ T (490 to 2 409 x 10³T) for TM4/TM3; at 515 x 10³t (331 to 757 x 10³t) for TM4/TM5 and 726 x 10³t (398 to 1 210 x 10³t) for TM4/TM7. The average biomass estimation of the NDVI using TM4rTM3 is similar to the estimation using the classification approach, but the 95% confidence Interval is wider. Meanwhile, the biomass estimation of the NDVI using TM4/TMI5 and TM4/TM7 was lower than the biomass estimation from the classification approach, but both showed a narrow 95% confidence interval. The results of this study Indicate that it is possible to estimate within a reasonable confidence interval the tree biomass of pine-oak forest using an ordination approach with NDVI As such, remote sensing could be used to estimate temporal and spatial changes in aboveground biomass.

Jorge, Escandón Calderón; Ben H. J. de, Jong; Susana, Ochoa Gaona; Ignacio, March Mifsut; Miguel Angel, Castillo.

1999-12-01

296

VoIP Technology: Investigation of QoS and Security Issues  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Amor Lazzez

2014-01-01

297

Evaluación de la capacidad de redes 802.11e transportando VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Estudio de la capacidad VoIP en redes WLAN IEEE 802.11 con simulación de resultados mediante software Scilab. En este trabajo se desarrollan y modelan las conclusiones obtenidas en el artículo 'Capacity Evaluation of VoIP in IEEE 802.11e WLAN Environment', obteniendo capacidad y rendimiento de cada uno de los códecs más utilizados en VoIP (G.711, G.729 y G.723.1).

Sa?nchez Torres, Pedro

2012-01-01

298

Impact of VoIP and QoS on Open and Distance Learning  

Science.gov (United States)

Voice over Internet Protocol (VoIP) is becoming a reality in many organizations. The potential for mobility in voice over wi-fi networks will derive demand for the technology. Wireless VoIP is poised to rival VoIP as an alternative telephony tool. Internet has been used to transport data in the form of packet. In the past, Internet did not support…

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

2006-01-01

299

Comparative Study of VoIP over WiMax and WiFi  

Directory of Open Access Journals (Sweden)

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

M Atif Qureshi

2011-05-01

300

Effects of aluminum substitution on photocatalytic property of BiVO4 under visible light irradiation  

International Nuclear Information System (INIS)

Graphical abstract: Visible-light-driven Al/BiVO4 photocatalyst was prepared by a hydrothermal process. After introducing Al, the BiVO4 particles retain monoclinic scheelite structures and the ability of visible light absorption is enhanced. XPS and FTIR results reveal that the Al ions influence the local structure of the BiVO4. The photocatalytic experiments demonstrate that the Al species incorporation can effectively enhance the photocatalytic activity of BiVO4 due to the existence of distorted VO43? tetrahedron and the stronger optical absorption intensity. Highlights: ? The visible-light-driven Al/BiVO4 photocatalysts are first prepared in our study. ? It is found that Al is introduced into the BiVO4 lattice successfully. ? The Al-doped BiVO4 shows a far higher photocatalytic activity than undoped BiVO4. ? One of the reason for the higher activity is the distorted VO43? tetrahedron. ? Another reason for the higher activity is the strong optical absorption intensity. -- Abstract: Novel visible-light-driven Al/BiVO4 photocatalysts were synthesized via a facile hydrothermal method for the first time. The samples were characterized by X-ray diffraction, N2-sorption, UV–vis diffuse reflectance spectra, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier transformed infrared spectra and X-ray photoelectron spectroscopy. The photocatalytic activity of the samples was evaluated by the decomposition of methylene blue under visible light irradiation (400 nm 4. The results revealed that the introduction of Al can improve photocatalytic performance greatly and different concentration of Al resulted in different photocatalytic activity. The highest activity is obtained by the sample with a doping concentration of 12 at%. The reason for the enhanced photocatalytic activities of Al/BiVO4 samples was also discussed in this paper.

 
 
 
 
301

Kualitas Percakapan Pada Jaringan VoIP Dengan Protokol SIP Menggunakan Metode Kualitatif Dan Kuantitatif  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Voice Over Internet Protocol (VoIP) adalah salah satu contoh perkembangan teknologi komunikasi dan informasi saat ini. VoIP merupakan suatu teknologi yang memberikan kemudahan bertelepon melalui internet. Namun yang menjadi masalah dalam penggunaan teknologi ini adalah banyaknya persepsi masyarakat yang menyatakan bahwa kualitas suara pada percakapan VoIP masih tergolong buruk. Hal ini banyak disebabkan oleh penggunaan codec yang tidak sesuai dengan kapasitas jaringan dan masalah pada jaringa...

Tanaka, Rudy

2010-01-01

302

A study of mobile VoIP performance in wireless broadband networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Arjona, Andres

2009-01-01

303

Synthesis, characterization and photocatalytic activities of rare earth-loaded BiVO{sub 4} catalysts  

Energy Technology Data Exchange (ETDEWEB)

The BiVO{sub 4}-based photocatalysts loaded with rare earth (RE=Ho, Sm, Yb, Eu, Gd, Nd, Ce and La) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), nitrogen adsorption for the BET specific surface area and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were evaluated by decolorization of methylene blue (MB) under visible light irradiation. The results of XRD, SEM and XPS analysis deduced that the rare earth ions were present as RE{sub 2}O{sub 3} in the samples. The DRS analysis showed the shift in the absorbption edge from the UV to the visible range: Ho{sup 3+}-BiVO{sub 4} < Sm{sup 3+}-BiVO{sub 4} < Yb{sup 3+}-BiVO{sub 4} < Eu{sup 3+}-BiVO{sub 4} < Gd{sup 3+}-BiVO{sub 4} < Nd{sup 3+}-BiVO{sub 4} < La{sup 3+}-BiVO{sub 4} < Ce{sup 3+}-BiVO{sub 4} < BiVO{sub 4.} Gd{sup 3+}-BiVO{sub 4} had the highest photocatalytic activity among all the RE{sup 3+}-BiVO{sub 4} catalysts. The optimal Gd content was 8 at% under visible light irradiation. This beneficial effect was attributed to the specific electron structure characteristics of gadolinium and the increasing in the separation efficiency of the electron-hole pairs. On the contrast, the other rare earth ions had the detrimental effect on the photocatalytic decolorization of MB.

Xu Hui [College of the Environment, Jiangsu University, Zhenjiang 212013 (China); College of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Wu Chundu, E-mail: wucd@ujs.edu.cn [College of the Environment, Jiangsu University, Zhenjiang 212013 (China); Yangzhou College of Environment and Resource, Yangzhou 225117 (China); Li Huaming [College of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Chu Jinyu [College of the Environment, Jiangsu University, Zhenjiang 212013 (China); Sun Guangsong; Xu Yuanguo; Yan Yongsheng [College of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

2009-11-15

304

Comparative Study of VoIP over WiMax and WiFi  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

305

Optimization of thermochromic VO2-based structures with tunable thermal emissivity  

International Nuclear Information System (INIS)

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

306

Active Timing Based Approach for Tracking Anonymous Peer-to-peer Network in VoIP  

Directory of Open Access Journals (Sweden)

Full Text Available Peer-to-peer VoIP calls are popular due to theirlow cost and convenience. When these calls are encrypted andanonymized the network becomes a secured one. Tracing of theanonymous VoIP call users are important and the tracedinformation about them should be sent to the server to knowhow long the users are in communication.The key challenge in tracking encrypted VoIP calls acrossanonymous communication system is to identify the correlationbetween the VoIP flows of the caller and the callee. Since all thetraffic of the peer-to-peer VoIP calls are encrypted, the best wayto track anonymous VoIP calls across the internet is using theActive timing based correlation. It is done by embedding aunique watermark into the inter-packet timing domain. Theanalysis shows that it only takes several milliseconds timeadjustment to make normal VoIP flows highly unique and theembedded delay value could be preserved across the low latencyanonymizing network. In this proposal, tracking of anonymousVoIP calls across internet was successfully achieved by usingactive time based correlation method and the resultsdemonstrate that tracing of anonymous peer-to-peer VoIP callson the internet is feasible and low latency anonymizing networksare susceptible to timing attacks.

Karthikeyan.C

2013-01-01

307

VoIP over Multiple IEEE 802.11 Wireless LANs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Prior work indicates that 802.11 is extremely inefficient for VoIP transport. Only 12 and 60 VoIP sessions can be supported in an 802.11b and an 802.11g WLAN, respectively. This paper shows that the bad news does not stop there. When there are multiple WLANs in the vicinity of each other, the already-low VoIP capacity can be further eroded in a significant manner. For example, in a 5-by-5, 25-cell multi-WLAN network, the VoIP capacities for 802.11b and 802.11g are only 1.63 ...

Chan, A.; Liew, S. C.

2007-01-01

308

Active Timing Based Approach for Tracking Anonymous Peer-to-peer Network in VoIP  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Peer-to-peer VoIP calls are popular due to theirlow cost and convenience. When these calls are encrypted andanonymized the network becomes a secured one. Tracing of theanonymous VoIP call users are important and the tracedinformation about them should be sent to the server to knowhow long the users are in communication.The key challenge in tracking encrypted VoIP calls acrossanonymous communication system is to identify the correlationbetween the VoIP flows of the caller and the callee. Since...

Karthikeyan.C; Karthikeyan.V; Jerin Sajeev.C.R,; Merlin Moses.M,

2013-01-01

309

IAX-Based Peer-to-Peer VoIP Architecture  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

310

Temperature-agile and structure-tunable optical properties of VO2/Ag thin films  

International Nuclear Information System (INIS)

By integrating together VO2's unique near-room-temperature (RT) semiconductor-metal (S-M) phase transition with a thin silver (Ag) layer's plasmonic properties, VO2/Ag multilayers could present a much enhanced optical transmission change when increasing the temperature from RT to over VO2's S-M phase-transition temperature. Changing VO2 and Ag layer thicknesses can also significantly tune their transmission and absorption properties, which could lead to a few useful designs in optoelectronic and energy-saving industries. (orig.)

311

Time limit at VO2max velocity in elite crawl swimmers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

he purpose of this study is to assess, with elite crawl swimmers, the time limit at the minimum velocity corresponding to maximal oxygen consumption (TLim-vVO2max), and to characterize its main determinants. Eight subjects performed an incremental test for vVO2max assessment and, forty-eight hours later, an all-out swim at vVO2max until exhaustion. VO2 was directly measured using a telemetric portable gas analyzer and a visual pacer was used to help the swimmers keeping the predetermined velo...

Ricardo Fernandes; Kari Keskinen; Paulo Colaço; Ana Querido; Leandro Machado; Pedro Morais; Daniel Novais; Daniel Marinho; João Paulo Vilas Boas Soares Campos

2008-01-01

312

Adsorption-controlled growth of BiVO4 by molecular-beam epitaxy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Single-phase epitaxial films of the monoclinic polymorph of BiVO4 were synthesized by reactive molecular-beam epitaxy under adsorption-controlled conditions. The BiVO4 films were grown on (001) yttria-stabilized cubic zirconia (YSZ) substrates. Four-circle x-ray diffraction, scanning transmission electron microscopy (STEM), and Raman spectroscopy confirm the epitaxial growth of monoclinic BiVO4 with an atomically abrupt interface and orientation relationship (001)BiVO4 ? (001)YSZ with [100]...

Stoughton, S.; Showak, M.; Mao, Q.; Koirala, P.; Hillsberry, D. A.; Sallis, S.; Kourkoutis, L. F.; Nguyen, K.; Piper, L. F. J.; Tenne, D. A.; Podraza, N. J.; Muller, D. A.; Adamo, C.; Schlom, D. G.

2013-01-01

313

Un modelo simple para describir la dinámica de la biomasa del camarón nailon Heterocarpus reedi en Coquimbo, Chile / A simple model for describing the biomass dynamics of the nylon shrimp Heterocarpus reedi at Coquimbo, Chile  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish RESUMEN. Entre septiembre de 1997 y agosto de 2000 se realizó un seguimiento diario de la dinámica espacial y temporal de la CPUE (ton·lance-1) de camarón nailon por parte de la flota arrastrera con puerto base en Coquimbo. Se construyó un modelo de remoción de biomasa modificado para explicar las v [...] ariaciones temporales de la CPUE basado en los conceptos de abundancia (biomasa total poblacional) y disponibilidad (biomasa que puede ser potencialmente capturada). Ambas cantidades fueron calculadas por ecuaciones, cuyas diferencias (positivas o negativas) indicaron los cambios en la disponibilidad de la biomasa a través del tiempo y el reclutamiento (magnitud y temporalidad). El modelo modificado indicó dos períodos anuales de distinta longitud en la disponibilidad de biomasa al arte de pesca. También indicó una tasa de reducción más acelerada para la biomasa que para la CPUE. Los resultados pueden influir en la determinación de la época óptima para la realización de las evaluaciones directas del recurso con fines de determinar cuotas de captura Abstract in english A daily record of space/time dynamics was carried out on CPUE (ton·trawl-1) for the nylon shrimp trawl fishery based at Coquimbo, Chile, between September 1997 and August 2000. A modified biomass depletion model was constructed to analyze the temporal variations in CPUE based on the concepts of abun [...] dance (total population biomass) and availability (potential biomass capture). Both quantities were calculated by equations whose differences (positive and negative) indicated the changes in availability of biomass over time, as well as recruitmernt (magnitude and seasonality). The modified model suggested there were two periods annually, of different lengths, and different biomasses available with the fishing gear. The model also indicated a more rapid rate of reduction in biomass than did the CPUE. The results could influence the determination of the best season for carrying out direct resource evaluations aimed at determining catch quotas

Eduardo P., Pérez.

2005-11-01

314

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-01-01

315

Método basado en teledetección para estimar la emisión de gases efecto invernadero por quema de biomasa A remote sensing method to estimate greenhouse gas emissions from biomass burning  

Directory of Open Access Journals (Sweden)

Full Text Available La quema de biomasa es una fuente importante de gases efecto invernadero en países en vías de desarrollo. En Colombia, el cambio de uso del suelo, la silvicultura y el sector agropecuario superan el 50% de las emisiones totales de efecto invernadero. El fuego se utiliza con frecuencia como un mecanismo para cambiar el uso del suelo. Los Llanos orientales y la Amazonía colombiana están sometidos todos los años a la quema de biomasa, especialmente entre enero y marzo. Los estudios en la distribución espacial y temporal de las emisiones son importantes de cara a los informes en el ámbito nacional. Este artículo de revisión describe el método para hacer estas estimaciones utilizando teledetección y algunos de los resultados disponibles para Colombia.Biomass burning is a major source of greenhouse gas emissions in developing countries. In Colombia, land use change, forestry and agriculture are responsible for more than 50% of the total greenhouse gas emissions. Fire is commonly used as a mechanism for land use change. In Colombia the Llanos Orientales and the Amazonia are subject to biomass burning every year during the dry season, especially from January to March. Studies of the spatial and temporal distribution of emissions are required for emissions report at a national level. The goal of this state of the art article is to describe a method to estimate emissions with a remote sensing approach and to present some of the variables already measured in Colombia.

Jesús Adolfo Anaya Acevedo

2011-01-01

316

Efecto del estrés hídrico simulado y la inoculación con esporas de Glomus mosseae sobre el crecimiento y la partición de biomasa en avena  

Directory of Open Access Journals (Sweden)

Full Text Available El estrés hídrico limita el rendimiento de las plantas. La micorriza favorece el crecimiento y confiere resistencia a la sequía. El objetivo de este trabajo fue estudiar el efecto del estrés hídrico moderado sobre la micorrización, el crecimiento y la partición de biomasa en plantas de avena (Avena sativa L. inoculadas con esporas de Glomus mosseae, a diferentes profundidades. Se sembró avena en sustrato estéril sin esporas y con 100 esporas a 4, 8 ó 12 cm de profundidad. La mitad de las plantas se sometieron a estrés moderado. Se determinó: área foliar, peso seco de parte aérea y raíz, porcentaje de colonización y dependencia micorrícica. Después de 60 días de la siembra, el porcentaje de colonización en las plantas regadas e inoculadas a 4 y 8 cm de profundidad y en las estresadas, a 4 cm de profundidad, fue de 25%, mientras que en el resto de los tratamientos fue significativamente menor. La biomasa seca aérea y de raíz fue significativamente mayor en las plantas estresadas inoculadas, a 8 y a 12 cm de profundidad, comparadas con las del tratamiento testigo. La arquitectura de las raíces estresadas se modificó con la inoculación: mostraron una menor longitud y un aumento significativo de las raíces laterales. Las plantas estresadas presentaron mayor dependencia micorrícica, comparadas con las no estresadas. Según estos resultados, la inoculación con esporas de G. mosseae fue una estrategia favorable para soportar situaciones de estrés hídrico y la ubicación del inóculo fue un factor determinante en la respuesta de la planta.

M. F. Ruscitti

2007-01-01

317

VoIP Technology: Investigation of QoS and Security Issues  

Directory of Open Access Journals (Sweden)

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

Amor Lazzez

2014-06-01

318

Influence of inoculum on growth and retention of the biomass in anaerobic filters / Influencia del inoculo sobre el crecimiento y la retención de biomasa en filtros anaerobios  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish En este estudio se evaluaron dos filtros anaerobios de igual configuración en escala de laboratorio y usando cáscara de coco como material de soporte, para el tratamiento de las aguas residuales del proceso de extracción de almidón de yuca. Considerando que en el área de estudio el inóculo disponibl [...] e en cantidad suficiente es el estiércol de vaca, se usó este inóculo solo (Reactor R1) y combinado con lodo granular en una proporción 1:1 (Reactor R2). Se evaluó la influencia del inóculo sobre el desempeño de los filtros anaerobios, sobre la adaptación de la biomasa al sustrato y sobre el crecimiento prevalente en el material de soporte. Ambos reactores mostraron potencial para el tratamiento de estas aguas residuales, con un Tiempo de Retención Hidráulico (TRH) de aproximadamente 12 horas, Carga Orgánica Volumétrica (COV) de 7.0 kg DQO/m3*d y un Índice Buffer (IB) entre 0.20 y 0.35. El incremento hasta de 50% en la Actividad Metanogénica Específica (AME) al final del arranque en ambos reactores, confirmó la adecuada adaptación de la biomasa al sustrato como resultado del control de la capacidad buffer; adicionalmente, los mayores valores de AME en el R2 mostraron que la mezcla de estiércol de vaca con lodo granular mejoró la producción de metano y la eficiencia del proceso. Se encontró que la biomasa ocluida tuvo mayor actividad que la biomasa adherida, indicando que el medio de soporte favoreció el desarrollo de una mayor proporción de biomasa activa en los intersticios del material de soporte. Abstract in english In this study we evaluated, on bench scale, two anaerobic filters of equal configuration and using coconut shell as support material, for the treatment of the wastewater generated in cassava's starch extraction process. Considering that in the study area the inoculum available in enough quantity is [...] cow manure, this inoculum was used alone (Reactor 1) and mixed with granular sludge in a ratio of 1:1 (Reactor 2). The influence of inoculum was evaluated in the performance of the anaerobic filters as well as in the biomass adaptation to the substrate and the prevalent growth on support material. Both reactors showed potential for the treatment of this type of wastewater, with a Hydraulic Retention Time (HRT) of 12 hours, an average Organic Loading Rate (OLR) of 7.0 kg COD/m3*d and a Buffer Index (BI) that varied from 0.20 to 0.35. The increase up to 50% in the Specific Methanogenic Activity (SMA) at the end of the start-up in both reactors, confirmed the adequate biomass adaptation to the substrate as a result of the control of buffer capacity, and the higher values in the R2, showed that cow manure mixed with granular sludge improved methane production and process efficiency. It was found that the occluded biomass had greater activity than the attached one; this showed that the support material allowed the development of a greater proportion of active biomass within the interstices.

Patricia, Torres-Lozada; Andrea, Pérez-Vidal.

2014-09-01

319

?-K(VO2)2(PO4)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new vanadium oxide, potassium bis(dioxovanadyl) phosphate, ?-K(VO2)2(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, a...

Safa Ezzine Yahmed; Meriem Ayed; Mohamed Faouzi Zid; Ahmed Driss

2013-01-01

320

?-K(VO2)2(PO4)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new vanadium oxide, potassium bis­(dioxovanad­yl) phosphate, ?-K(VO2)2(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.

Ezzine Yahmed, Safa; Ayed, Meriem; Zid, Mohamed Faouzi; Driss, Ahmed

2012-01-01

 
 
 
 
321

β-K(VO2)2(PO4)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new vanadium oxide, potassium bis(dioxovanadyl) phosphate, ?-K(VO2)2(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 number...

Safa Ezzine Yahmed; Meriem Ayed; Mohamed Faouzi Zid; Ahmed Driss

2013-01-01

322

Comprehensive picture of VO2 from band theory  

Science.gov (United States)

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

Zhu, Zhiyong; Schwingenschlögl, Udo

2012-08-01

323

VoIP Steganography and Its Detection - A Survey  

CERN Document Server

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

Mazurczyk, Wojciech

2012-01-01

324

Bulk and electrochemical properties of BiVO4  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1992-01-01

325

Comprehensive picture of VO2 from band theory  

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

Zhu, Zhiyong

2012-08-28

326

Spin-singlet state in Sb2VO5  

International Nuclear Information System (INIS)

We have measured the high-field magnetization of a quasi-one dimensional S=1/2 chain compound Sb2VO5, which was proposed as a new candidate of the inorganic spin-Peierls (SP) system. The magnetization measured at 4.2 K exhibits a clear inflection at around 23 T, indicating obviously the excitation from a spin singlet ground state to a triplet state. Absence of anomalies in specific heat and X-ray diffraction points to no SP transition, and the analysis of the susceptibility suggests that this compound is an alternating spin chain system.

327

Textured metastable VO2 (B) thin films on SrTiO3 substrates with significantly enhanced conductivity  

International Nuclear Information System (INIS)

Textured metastable VO2 (B) thin films with a layered structure were grown on SrTiO3 (001) by pulsed laser deposition. The X-ray diffraction and transmission electron microscopy results indicate that VO2 (B) films exhibit c-axis out-of-plane, while the films have 4 possible in-plane matching relations. In addition, a small amount of VO2 (M) phase can co-grow in the VO2 (B) phase when the film thickness exceeds a threshold. The thick VO2 films on STO exhibit a sharp metal-insulator transition with an increase of electrical conductivity in two orders of magnitude. This study may provide an alternative approach to enhance the performance of insulating VO2 (B) based batteries with increased electrical conductivity by incorporating VO2 (M) phase in the VO2 (B) phase layered network

328

Semiconductor to metal transition characteristics of VO2 thin films grown epitaxially on Si (001)  

Science.gov (United States)

We report semiconductor to metal transition (SMT) characteristics of vanadium dioxide (VO2) grown epitaxially on Si (001) at 500 °C. The epitaxial integration with Si (001) was achieved by using epitaxial tetragonal yttria-stabilized zirconia (YSZ) as an intermediate buffer layer, which was grown in situ. From x-ray (?-2? and ?-scan) and electron diffraction studies, we established that VO2 and YSZ grow in (020) and (001) orientations, respectively, on Si (001) substrate and epitaxial relationship was established to be "VO2[001] or VO2[100]"//YSZ[110]//Si [100] and VO2(010)//YSZ(001)//Si(001). VO2/YSZ/Si(001) heterostructures showed approximately three orders of magnitude reversible change in resistivity and hysteresis of ˜6 K upon traversing the transition temperature. A 10 °C increase in the SMT temperature of these VO2 films, compared to the value reported for bulk VO2, has been explained on the basis of uniaxial stress along the c-axis, which can stabilize the covalent monoclinic phase up to higher temperatures. A correlation between in-plane orientations of the film and the transition width has also been suggested, which is consistent with our previously published thermodynamic model.

Gupta, A.; Aggarwal, R.; Gupta, P.; Dutta, T.; Narayan, Roger J.; Narayan, J.

2009-09-01

329

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

Directory of Open Access Journals (Sweden)

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

Kashif Nisar

2011-02-01

330

VoIP: A Corporate Governance Approach to Avoid the Risk of Civil Liability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Since the deregulation of Voice over Internet Protocol (VoIP) in 2005, many South African organizations are now attempting to leverage its cost saving and competitive values. However it has been recently cited that VoIP is one of the greatest new risks to business. This risk is cited to i...

Mariana Gerber; Kerry-Lynn Thomson; Tian Gerber

2013-01-01

331

MAXIMAL OXIGEN UPTAKE (VO2 MAX AS THE INDICATOR OF PHYSICAL WORKING CAPACITY IN SPORTSMEN  

Directory of Open Access Journals (Sweden)

Full Text Available The term “aerobic capacity” represents the sum of aerobic metabolic processes in human organism. It is the basis of the physical working capacity. Value of the maximal oxygen uptake (VO2max is the best indicator for the aerobic capacity evaluation.The purpose of this study was to check the possibility of using VO2max as the indicator of aerobic capacity in sportsmen and to check differences in VO2max values in regard to non-sportsmen.The goals were: 1.Analyses of the VO2max values in sportsmen of various sports 2. Comparison of values of sportsmen with the values of non-sportsmen.This study included 67 sportsmen (rowers, football players and judoists and 28 nonsportsmen. VO2max was measured by using a direct method.The results obtained show statistically higher VO2max values in rowers (4,52 L/min - 55,8 mL/kg/min in regard to football players (4,2 L/min – 53,6 mL/kg/min, judoists (3,58 L/min - 47,2 mL/ kg/min and non-sportsmen (3,28 L/min – 42,3 mL/kg/min. Successful rowing requires high anaerobic capacity and, therefore, high VO2max.These results show higher values of VO2max in sportsmen in regard to non-sportsmen, which is the result of training only.

Zvezdana Rajkovaca

2005-12-01

332

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

Science.gov (United States)

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

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

2007-01-01

333

Localization of 3d electrons in VO2+Ar solid solutions  

International Nuclear Information System (INIS)

Electroconductivity ?, transmission spectra t, light reflection R and optical conductivity ?sub(opt) in the temperature range T from 77.8 to 400 K for VO2 samples and VO2+Ar solid solutions on their base are measured. Preparation of the latter has been realized by the ion implantation method in the implantation dose range from 0 to 6.1016 cm-2. At implantation doses higher than 1016 cm-2 the transition into isolator state at high T, has been found, the transformation of R and ?sub(opt) spectra in the process of this transition is analogous to their variation at ''temperature'' phase transition metal-isolator in VO2 crystals. The found effect is related to increase of average distances between lattice atoms of VO2 in the VO2+Ar system leading to 3d-electron localization or Mott transition into isolator state. Discussion of 3d-electron properties in VO2 is presented and considerations on the character of conformity of isolator state in the VO2+Ar system to isolator state in low-temperature monoclinic VO2 crystal phase are set forth

334

Effects of porous nano-structure on the metal–insulator transition in VO2 films  

International Nuclear Information System (INIS)

Graphical abstract: The picture shows the morphology and hysteresis loop of porous VO2 film: porous nano-structure with small nanoparticles is obtained, transition temperature is reduced to 56 °C and hysteresis width is increased to 36 °C. Highlights: ? VO2 films with small nanoparticles and homogeneous pores are obtained. ? Tt of porous nano-structure VO2 film is reduced to 56 °C and ?T is increased to 36 °C. ? Systematic study of CTAB concentration on morphology and MIT properties of the VO2 films is conducted. - Abstract: In this work, we confirmed experimentally that the porous nano-structure of vanadium dioxide (VO2) films had significant effects on the features of the metal–insulator transition. Porous VO2 films had been synthesized on mica substrates via a simple solution process with inorganic precursor and cetyltrimethyl ammonium bromide (CTAB). SEM images showed a combination of homogenously distributed pores and VO2 nanoparticles. Metal to insulator transition (MIT) characteristics measurements revealed that, the porous nano-structure VO2 films had low transition temperature, wide hysteresis width and gentle slopes of hysteresis loop. Morphologies and MIT characteristics of the films could be controlled by simply varying CTAB concentration, which is of great importance in achieving practical applications.

335

Adsorption-controlled growth of BiVO4 by molecular-beam epitaxy  

Directory of Open Access Journals (Sweden)

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

S. Stoughton

2013-10-01

336

Wavelength-Tunable Infrared Metamaterial by Tailoring Magnetic Resonance Condition with VO2 Phase Transition  

CERN Document Server

In this work, we report the design of a wavelength-tunable infrared metamaterial by exciting magnetic resonance with phase transition of vanadium dioxide (VO2). Numerical simulation shows a broad absorption peak at the wavelength of 10.9 um when VO2 is a metal, but it shifts to 15.1 um when VO2 changes to dielectric phase below its phase transition temperature of 68degC. The large tunability of 38.5% in the resonance wavelength stems from the different excitation conditions of magnetic resonance assisted by plasmon in metallic VO2 but optical phonons in dielectric VO2. The physical mechanism is elucidated with the aid of electromagnetic field distribution at the resonance wavelengths. A hybrid magnetic resonance mode due to plasmon-phonon coupling is also discussed. The results here would be beneficial for active control in novel electronic, optical and thermal devices.

Wang, Hao; Wang, Liping

2014-01-01

337

Crystal structures and transition mechanism of VO2(A)  

International Nuclear Information System (INIS)

Structures of VO2(A) have been redetermined by single-crystal diffractometry for low- (LTP) and high-temperature (HTP) phases at 298 and 473 K, respectively. The LTP adopts the tetragonal system P4/ncc with a = 8.4403(9) angstrom, c = 7.666(1) angstrom, and Z = 16, whereas the HTP adopts the body-centered tetragonal system I4/m with a = 8.476(2) angstrom, c = 3.824(2) angstrom, and Z = 8. The refinements led to R/Rw = 0.031/0.032 for LTP and 0.012/0.033 for HTP. The structures of both phases consist of edge-sharing VO6 octahedra and exhibit quite similar oxygen frameworks. Through the transition the V4+-V4+ bonding in LTP with a distance of 2.7695(8) angstrom is dissociated in HTP to a distance of 3.0794(3) angstrom. The transition occurs with cooperative movements of the V atoms, namely, a rotation around the c axis and a shift along the c axis. Strangely, twinning is induced on the LTP to HTP transition but disappears on the reverse transition

338

Cation self-diffusion in disordered VO/sub x/  

International Nuclear Information System (INIS)

Diffusion of 48V in disordered VO/sub x/ crystals was measured by a serial sectioning technique as a function of temperature (1100-15000C) over the entire homogeneity range (0.75 0C. The Arrhenius parameters vary significantly as the composition varies from the metal-rich to metal-deficient regime; the activation energy for diffusion decreases from approx.71 kcal/mole to approx.48 kcal/mole, and the frequency factor decreases by nearly two orders of magnitude, from approx.5 cm2/sec to approx.0.05 cm2/sec. The decrease in the Arrehenius parameters appears to be abrupt near the stoichiometric composition. The cation diffusivity increases by nearly an order of magnitude at 15000C and by nearly two orders of magnitude at 11000C over the composition range, indicating a nonideal behavior and strong defect-defect interactions. It is concluded that the significant difference in the cation self-diffusion behavior of the metal-rich and the metal-deficient VO/sub x/ may be attributed to the significant differences in the defect structures of the two regimes

339

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-05-25

340

76 FR 59916 - Interconnected VoIP Service; Wireless E911 Location Accuracy Requirements; E911 Requirements for...  

Science.gov (United States)

...05-196; FCC 11-107] Interconnected VoIP Service; Wireless E911 Location Accuracy...rules requiring providers of interconnected VoIP service to supply E911 capabilities to...service. The rules adopted in the 2005 VoIP 911 Order apply only to providers of...

2011-09-28

 
 
 
 
341

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

Directory of Open Access Journals (Sweden)

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

César A García-Ubaque

2013-01-01

342

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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish 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 m [...] ateriales más adecuados para utilizar como combustible alternativo. El sector ladrillero tiene una gran demanda energética para sus procesos de secado y cocción y el uso de combustibles alternativos a partir de biomasa permite obtener reducciones importantes en emisiones atmosféricas y no afecta las condiciones técnicas del proceso de producción de ladrillos. La biomasa con mejor desempeño, tanto en las variables energéticas como ambientales evaluadas, fue el aserrín. Abstract in english This study compared the energy and environmental performance of fuels from two types of pelleted biomass: wood waste from pruning and waste from furniture production, mainly sawdust. Wood residues biomass is one of the most suitable materials for using as an alternative fuel. The brick manufacture s [...] ector has a high energy demand for its drying and firing processes and the use of alternative fuels from biomass allows significant reductions in emissions and does not affect the technical conditions of the process of brick production. The biomass with better performance was sawdust, which presented the optimum energy and environmental variables.

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

343

Prepaid and Postpaid VoIP Service Enhancements and Hybrid Network Performance Measurement  

Directory of Open Access Journals (Sweden)

Full Text Available This study focuses on prepaid and postpaid VoIP technology service enhancement. The aims are to i merge wireless technology in rural areas with wired technologies and services in urban areas. It intends to investigate the minimum requirement needs by wireless and wired technology in using of telco connectivity. It is also to define which technology will achieve a low operating cost and good performance. In addition, the most apparent benefit of implementing prepaid/postpaid VoIP network in rural areas is that to achieve a robust fault tolerance and load-balancing voice traffic between urban and rural areas. ii Merging of WAP and VoIP network to provide Information-on-Demand (IoD services to prepaid and postpaid VoIP users. It is to provide value added services for prepaid and postpaid VoIP users. WAP and other similar technologies will continue to play an important role in the development of Information-on-Demand (IoD services in future. In addition, the most apparent benefit of implementing WAP technology with prepaid/postpaid VoIP network architecture is that to achieve WAP enabled mobile to access this facility during travelling, meeting, seminar and conference. Integration of WAP technology with prepaid/postpaid VoIP network architecture can achieve efficiency end-to-end information services between service providers (ISPs/ITSPs and WAP mobile phone users. Therefore, prepaid and postpaid VoIP service enhancement can improve and obtain high efficiency network, technical, business and customer-care aspects in contributing the robust prepaid/postpaid VoIP network architecture for prepaid/postpaid VoIP users.

Mohd Nazri Ismail

2006-01-01

344

Estimación de la biomasa foliar de Prosopis flexuosa mediante relaciones alométricas / Estimation of leaf biomass in Prosopis flexuosa by means of allometric relationships  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish La estimación alométrica de la biomasa foliar arbórea es necesaria para determinar la producción primaria y para analizar algunas de las interacciones ecológicas entre los árboles y los demás componentes de la vegetación. El objetivo del trabajo fue ajustar y seleccionar modelos para estimar la biom [...] asa foliar de Prosopis flexuosa a partir de variables dendrométricas. Se apearon seis árboles, se midió su diámetro y se calculó el área de albura de muestras transversales de leño, en cuatro niveles: en los órdenes de ramificación dentro de la copa viva (ramas secundarias, terciarias y cuaternarias agrupadas), en el extremo distal de las ramas primarias y en los extremos distal y basal del fuste. Se recolectaron las hojas correspondientes a cada nivel y se obtuvo el peso seco. El área de albura fue la mejor variable predictora de biomasa foliar, aunque el diámetro tuvo buen ajuste en ramas dentro de la copa viva y en ramas primarias. Los modelos calculados con variables de fuste tuvieron menor ajuste. Se concluye que para la estimación no destructiva de la biomasa foliar de plantas adultas de Prosopis flexuosa es recomendable utilizar el modelo basado en el diámetro distal de las ramas primarias. Abstract in english The estimation of leaf biomass, usually performed by alometric relations, is important for the interpretation of primary production and for the assessment of ecological interactions between trees and the rest of the components in a wood vegetation. The goal for the present work was to adjust and to [...] select allometric models for the estimation of leaf biomass Prosopis flexuosa based on dendrometric variables. Six trees were surveyed. The diameter and sapwood area of transversal samples of wood were determined at four different levels: in the orders of ramification within living crown (secondary, tertiary and quaternary grouped branches), at the distal portions of primary branches and in the apical and basal portions of bole. The leaves were collected according to each level and dry mass was obtained. The sapwood area was the best predictor of leaf biomass, although diameter provided accurate estimations within crown and at the distal portions of primary branches. The models based on trunk dimensions were less precise. It is concluded that the obtained regression model based on the diameter of the distal portions of primary branches can be applied for the non-destructive estimation of leaf biomass in Prosopis flexuosa adult trees.

M., Ledesma; C.A., Carranza; M., Balzarini.

2010-12-01

345

Biomasa acústica y distribución del jurel Trachurus murphyi en el Perú / Acoustic biomass and distribution of Jack mackerel Trachurus murphyi in Peru  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish Se analizan los resultados de las evaluaciones hidroacústicas del recurso jurel Trachurus murphyi Nichols 1920 realizadas en aguas peruanas entre 1983 - 2012. Desde 1983 se incluyó al T. murphyi como especie de estudio durante los cruceros de evaluación de recursos pelágicos ejecutados por el Instit [...] uto del Mar del Perú. Debido al énfasis en la estimación de biomasa de la anchoveta Engraulis ringens y de la sardina Sardinops sagax cuando esta última es más abundante, los cruceros se llevan a cabo durante el verano austral y las áreas de evaluación están circunscritas a las zonas más costeras hasta 100 mn, con sólo algunas exploraciones en otras estaciones y hasta 200 millas. El máximo valor de biomasa de 8.51 millones de toneladas de T. murphyi en aguas peruanas estimado con las evaluaciones hidroacústicas fue encontrado durante el crucero realizado en otoño (marzo-mayo) de 1983. En los años siguientes los estimados de biomasa acústica fluctuaron entre 180 mil toneladas en 1985 y otro máximo de 8.47 millones de toneladas en 1993, para luego disminuir gradualmente hasta un mínimo de 1239 t en 2010, con una ligera recuperación en los años 2011 y 2012. El área de distribución de T. murphyi fue muy fluctuante en todo el periodo observado. Abstract in english This paper analyzes the results of acoustic stock assessment surveys for Jack mackerel Trachurus murphy Nichols 1920 conducted in Peruvian waters between 1983 and 2012. Since 1983 Jack mackerel T. murphyi was included as a target species to be assessed during the pelagic stock assessment surveys exe [...] cuted by the Peruvian Institute of Marine Research. Due to the emphasis on the assessment of anchovy Engraulis ringens and sardine Sardinops sagax when this species was abundant, these surveys usually took place during the austral summer and only covered the first 100 nautical miles from the coast, and only occasional surveys were conducted in other seasons or surveyed as far as 200 nm offshore. A maximum biomass of 8.51 million t of T. murphyi in Peruvian waters estimated through acoustics during a survey carried out in autumn (March-May) 1983. In the following years acoustic biomass estimates ranged between 180 thousand t in 1985 and another maximum of 8.47 million t in 1993, to then decreased gradually to a minimum of 1239 t in 2010, with a slight recovery in 2011 and 2012. The areas of ??distribution of T. murphyi have been fluctuating markedly throughout the observed period.

Marceliano, Segura; Aníbal, Aliaga.

2013-09-01

346

Relative Aerial Biomass Yield of Intercroped Alfalfa with Winter Forage Cereals / Rendimiento Relativo de Biomasa Aérea en Intercultivos de Alfalfa con Cereales Forrajeros de Invierno  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish En las regiones tropicales del mundo, el intercultivo está asociado con la producción de granos para la alimentación, mientras que en áreas templadas recibe mayor atención como medio de producción eficiente de forraje. El objetivo de este experimento fue determinar el rendimiento relativo de biomasa [...] aérea en intercultivos de alfalfa (Medicago sativa L.) y cereales forrajeros de invierno. Se establecieron ocho sistemas producto de la combinación con especies de cereales con distintas fechas de siembra. Las mediciones de biomasa se realizaron en tres situaciones: monocultivo de alfalfa, monocultivo de cereales e intercultivo de alfalfa-cereal, calculándose el rendimiento relativo del intercultivo (RRI). Se empleó un diseño con arreglo bifactorial y dos repeticiones en bloques completos al azar. Los intercultivos de alfalfa-cereal generaron valores de RRI entre 0,71 y 0,83, lo que indicó que en una misma superficie es posible producir entre el 71 y 83% de la biomasa que ambos cultivos producirían en superficies separadas. Abstract in english In the tropical regions of the world, intercropping is mostly associated with food grain production, whereas it is receiving increased attention in temperate regions as a means of efficient forage production. The aim of this work was to determine the relative yield of aerial biomass in alfalfa or lu [...] cerne (Medicago sativa L.) and winter forage cereals intercrops. These were done in eight systems resulting from the combination of species sown at different dates. The biomass was measured in three situations: alfalfa and cereal sole-crop and alfalfa-cereal intercrops, the relative biomass yields were calculated by the relative yield index (RYI). The field experiment was conducted as a bifactorial array in a randomized complete block design of two replicates. The alfalfa-cereal intercrops provided RYI values ranging from 0.71 to 0.83. This showed that it is possible to produce, in the same area, between 71 and 83% of the biomass that both crops would produce in separate ones.

Telmo, Pereyra; Héctor, Pagliaricci; Alfredo, Ohanian.

2008-09-01

347

Solid-state transformation of single precursor vanadium complex nanostructures to V?O? and VO?: catalytic activity of V?O? for oxidative coupling of 2-naphthol.  

Science.gov (United States)

A vanadium complex, [(C5H5N)2V2O3·H2O], of different morphologies has been obtained via a modified hydrothermal procedure using pyridine and VOSO4 salt as the starting material. The evolved [(C5H5N)2V2O3·H2O] nanobelts are of 50-200 nm in width and of a length up to several millimeters. At higher temperatures (600 °C), the solid [(C5H5N)2V2O3·H2O] nanostructures are converted to vanadium pentoxide (V2O5) and vanadium dioxide (VO2) when heated in air and nitrogen atmosphere, respectively. During growth, the mechanism of the evolution of octahedra, truncated octahedra, and hollow truncated octahedra of [(C5H5N)2V2O3·H2O] are reported for the first time. These types of well-structured morphology are also isolated while V2O5 and VO2 are evolved. The as-grown belt-like and octahedral morphologies of [(C5H5N)2V2O3·H2O] are retained during the solid-state transformation, suggesting a route to evolve crystalline nanomaterials. Again, the morphological evolution of the [(C5H5N)2V2O3·H2O] nanostructures has been examined to be pyridine and precursor vanadyl sulfate (VS) concentration dependent. Thus, we are able to isolate truncated octahedra as an intermediate during the formation of [(C5H5N)2V2O3·H2O] nanobelts and nanoflowers with a high pyridine (Py) concentration. Interestingly, longer reaction times successively featured the transformation of truncated octahedra into nanobelts. Nanobelt evolution is not observed at low pyridine concentrations. However, the formation of octahedral morphology takes place at low pyridine concentration. All of the nanostructures were critically examined and characterized thoroughly by various physical techniques to ascertain their purity, structure and composition. An interesting, thermodynamically stable, single crystalline product from DMF soluble [(C5H5N)2V2O3·H2O] has been characterized, which indirectly supports the composition of [(C5H5N)2V2O3·H2O]. Selectively, vanadium pentoxide nanobelts have been found to be an efficient catalyst for the oxidative coupling of 2-naphthol to binaphthols under a molecular oxygen atmosphere. PMID:25486444

Pradhan, Mukul; Roy, Anindita; Sinha, Arun Kumar; Sahoo, Ramkrishna; Deb, Dibakar; Pal, Tarasankar

2015-01-28

348

Variação diurna e resposta da cinética do VO2 de ciclistas durante exercício muito intenso / Diurnal variation and Vo2 kinetic response of cyclists during heavy exercis e  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo do presente estudo foi avaliar a influência da hora do dia nos parâmetros da cinética do consumo de oxigênio de ciclistas durante exercício muito intenso. Nove voluntários do sexo masculino realizaram exercícios de carga constante às 08:00, 13:00 e 18:00 h, em dias diferentes. Estes exerc [...] ícios foram realizados duas vezes em cada visita, com um intervalo de 1 h entre eles. A intensidade usada foi de 75%? (75% da diferença entre o VO2 no limiar de lactato e o VO2max. A amplitude do componente primário do VO2 (2597 ± 273 ml.min-1, 2513 ± 268 ml.min-1 e 2609 ± 370 ml.min-1), a constante de tempo do componente primário do VO2 (19.3 ± 2.5 s, 18.4 ± 3.0 s e 19.7 ± 3.9 s), o componente lento do VO2 (735 ± 81 ml.min-1, 764 ± 99 ml.min-1 e 680 ± 121 ml.min-1) e o tempo de resposta média (51.8 ± 4.2 s, 51.2 ± 4.2 s e 51.4 ± 3.4 s) não apresentaram diferenças significativas entre os diferentes horários do dia (08:00, 13:00 e 18:00 h), assim como os demais parâmetros da cinética do VO2. Estes resultados sugerem que a resposta da cinética do VO2 de ciclistas durante exercício muito intenso (75%?) não é influenciada pela hora do dia. Abstract in english The objective of the present study was to evaluate the influence of the time of day on the parameters of oxygen uptake kinetics of trained cyclists during high intensity exercise. Nine male volunteers repeated bouts at constant loads at 08:00, 13:00 and 18:00 h on different days. These exercise bout [...] s were performed twice on each occasion, with an interval of 1 h between them. The load intensity used was 75%? (75% of the difference between the VO2 at the lactate threshold and the VO2max). The primary VO2 amplitude (2597 ± 273 ml.min-1, 2513 ± 268 ml.min-1 and 2609 ± 370 ml.min-1), the primary VO2 time constant (19.3 ± 2.5 s, 18.4 ± 3.0 s and 19.7 ± 3.9 s), the VO2 slow component (735 ± 81 ml.min-1, 764 ± 99 ml.min-1 and 680 ± 121 ml.min-1) and the mean response time (51.8 ± 4.2 s, 51.2 ± 4.2 s and 51.4 ± 3.4 s) did not present significant differences at the different times (08:00, 13:00 and 18:00 h), neither did the other parameters of the VO2 kinetics. These results suggest that the response of the VO2 kinetics of cyclists exercising at high intensity (75%?) is not influenced by the time of day.

Marcos G., Santana; Sergio, Tufik; Giselle S., Passos; Donald M., Santee; Benedito S., Denadai; Marco T., Mello.

2008-06-01

349

Aerobic Fitness Level Typical of Elite Athletes is not Associated With Even Faster VO2 Kinetics During Cycling Exercise  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study was to address the question if the VO2 kinetics is further improved as the aerobic training status increases from trained to elite level athletes. Maximal oxygen uptake (VO2max), work-rate associated to VO2max (IVO2max) and VO2 kinetics of moderate (Mod) and maximal exercise (Max) were determined in fifty- five subjects. Then, they were assigned into three groups: low (LF), intermediate (IF) and high (HF) aerobic fitness level. In average, the VO2max of LF, IF and HF gro...

Figueira, Tiago R.; Fabrizio Caputo; Machado, Carlos E. P.; Denadai, Benedito S.

2008-01-01

350

Facile fabrication of an efficient BiVO4 thin film electrode for water splitting under visible light irradiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An efficient BiVO4 thin film electrode for overall water splitting was prepared by dipping an F-doped SnO2 (FTO) substrate electrode in an aqueous nitric acid solution of Bi(NO3)3 and NH4VO3, and subsequently calcining it. X-ray diffraction of the BiVO4 thin film revealed that a photocatalytically active phase of scheelite-monoclinic BiVO4 was obtained. Scanning electron microscopy images showed that the surface of an FTO substrate was uniformly coated with the BiVO4 film with 300–400 nm o...

Jia, Qingxin; Iwashina, Katsuya; Kudo, Akihiko

2012-01-01

351

Producción de biomasa de la microalga Scenedesmus sp. utilizando aguas residuales de pescadería / Biomass production of microalga Scenedesmus sp. with wastewater from fishery  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Las microalgas representan una alternativa para el tratamiento de aguas residuales por su capacidad de remoción de nutrientes y alto valor comercial de la biomasa producida. Se evaluó el crecimiento, remoción de nutrientes y materia orgánica de la microalga Scenedesmus sp. en aguas residuales deriva [...] das de restos de pescadería. Se utilizaron cultivos discontinuos en tanques a cielo abierto con 150L, aireación constante y en condiciones no controladas de fotoperiodo y temperatura. Se evaluó el crecimiento de la microalga mediante recuento celular, peso seco y contenido de pigmentos, realizando la recolección de la misma en fase estacionaria mediante sedimentación natural, y efectuando análisis fisicoquímicos a la biomasa secada al sol. La microalga creció en agua residual a cielo abierto, reportando eficiencias de remoción de 94,44% (23,80mg/L) para nitrógeno amoniacal, de 77,54% (7,04mg/L) para fosfatos y de 35,59% (26,09mg/L) para materia orgánica. La biomasa seca resultó ser un componente de alto contenido proteico (24,41%), fibroso (10,04%), con niveles de grasa (2,47%) y minerales (23,52%) adecuados para complementar la nutrición animal. Estos resultados demostraron que Scenedesmus puede ser utilizada para el tratamiento de aguas residuales con la producción de una biomasa de valor agregado. Abstract in english The microalgae represent an alternative for the treatment of wastewater for his capacity of removal of nutrients and high commercial value of produced biomass. There was evaluated the growth, removal of nutrients and organic matter of Microalgae Scenedesmus sp. in wastewater derived from remains of [...] fish. Discontinuous cultures were in use in tanks to sky opened with 150L, constant aeration and in conditions no controlled of photoperiod and temperature. The growth of microalgae we evaluated by means of cell counting, dry weight and content of pigments, realizing the compilation of the same one in stationary phase by means of natural sedimentation, and effecting physicochemical analyses to the biomass dried to the sun. The microalgae grew in wastewater to opened sky, reporting efficiencies of removal of 94.44% (23.80 mg/L) for ammonia nitrogen, 77.54% (7.04 mg/L) for phosphates and 35.59 % (26.09 mg/L) for organic matter. The dry biomass recollected was a component of high contained protein (24,41%), fibrous (10,04%), with levels of fats (2,47%) and mineral (23,52%) adapted to complement the animal nutrition. These results showed that Scenedesmus can be used for the treatment of wastewater by production of a biomass of added value.

Charity E, Andrade R; Alexandra L, Vera B; Carmen H, Cárdenas L; Ever D, Morales A.

2009-08-01

352

Modelo dinámico de crecimiento de la biomasa para Mytilus chilensis en sistemas de cultivo en líneas / Dynamic biomass growth model for Mytilus chilensis in longline culture systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Este estudio propone un modelo de crecimiento dinámico de la biomasa para el bivalvo Mytilus chilensis, en sistemas de cultivos en línea. El modelo propuesto determina la biomasa a través del peso medio total y el número de choritos por metro lineal en la cuerda de engorda, calibrado usando datos re [...] ales. El peso medio se determina a través del modelo de von Bertalanffy modificado que incorpora la disponibilidad de alimento del ambiente y el ciclo reproductivo a través del Índice de Rendimiento Productivo, el que corresponde al cociente entre el peso en carne y el peso total. Por lo anterior, el peso medio está determinado por la disponibilidad de alimento y el crecimiento biológico de la especie. El modelo supone que el número de individuos de choritos por metro en la cuerda es el resultado tanto de la competencia intraespecífica entre individuos de M. chilensis como de la interespecífica con individuos del mitílido Aulacomya atra por el espacio disponible en la misma cuerda. Para modelar la competencia por el espacio disponible se utilizó la tasa de crecimiento, la superficie ocupada por los individuos y el porcentaje de presencia de M. chilensis y de A. atra. El estudio se realizó en la cuenca de Rilán, isla de Chiloé, sur de Chile, por un periodo de 18 meses. Se obtuvo un R² ajustado = 0,98, 0,93, y 0,94 para la variación del tamaño, de la densidad lineal y la biomasa, respectivamente, lo que indica que el modelo propuesto puede ser utilizado para predecir la biomasa en el tiempo. Abstract in english A dynamic biomass growth model for the mussel Mytilus chilensis in longline culture systems in proposed. This model determines the biomass by estimating the average weight and the number of mussels per meter of seeded rope, using real data. The average weight is estimated using the von Bertalanffy m [...] odel modified to incorporate the availability of food in the environment and the reproductive cycle given by the Meat Yield Index, which is the quotient between the meat weight and the total weight. Therefore, the average weight is determined by the availability of food and the biological growth of the species. The model assumes that the number of mussel individuals per meter in the rope is the result of both the species intraspecific competition among M. chilensis individuals and the interspecific competition with individuals of the mytilid Aulacomya atra for the available space in the same seeded rope. The growth rate, the occupied surface and the presence percentage of M. chilensis and A. atra were used to model the competition for the available space. The study was performed at the Rilán basin in the Chiloé Island, southern Chile, during an 18-month period. The results obtained were an R² adjusted = 0.98, 0.93, and 0.94 for the variation in size, lineal density and biomass, respectively, which indicate that the proposed dynamic model can be used to predict the biomass over time.

José, Marambio; Sergio, Maturana; Bernardita, Campos.

2012-04-01

353

Producción de biomasa y costos de producción de pastos Estrella Africana (Cynodon nlemfuensis), kikuyo (Kikuyuocloa clandestina) y Ryegrass Perenne (Lolium perenne) en lecherías de Costa Rica  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish Se evaluó la producción de biomasa, los costos de producción y el costo del kilogramo de materia seca en los pastos kikuyo (Kikuyuocloa clandestina), ryegrass perenne (Lolium perenne) y estrella africana (Cynodon nlemfuensis), a lo largo de un año, en 8 fincas comerciales ubicadas en las provincias [...] de Cartago (2), San José (2) y Alajuela (4). La producción de biomasa promedio por ciclo para los 3 pastos fue de 3395 kg.ha-1 MS; la producción anual se ve influenciada por los días de recuperación de cada especie, mostrando valores de 40 170, 38 731 y 28 995 kg.ha-1 de MS para los pastos estrella africana, kikuyo y ryegrass perenne, espectivamente. La producción de biomasa varía durante el año y en las épocas de mayor producción de esa biomasa, los animales tienen un menor aprovechamiento de la pastura en términos porcentuales, debido a que la carga animal, los períodos de permanencia y las áreas de pastoreo no se ajustan a la disponibilidad de forraje. Los costos anuales de mano de obra, insumos y tierra promedio fueron de 72.433, 505.515 y 18.760 colones.ha-1, respectivamente; siendo los insumos el rubro con un peso relativo mayor en la estructura de costos de las fincas en pastoreo. Los costos del kg de MS producido y consumido, para los 3 pastos evaluados, fueron de 16,6 y 44,4 colones respectivamente, siendo el aprovechamiento que los animales hacen de las pasturas el determinante del costo del material consumido. Las fincas con mayor inversión anual en pasturas, mostraron un mayor retorno en kg.ha-1 leche. Abstract in english Dry matter yield and production costs in grazing systems on dairy farms of Costa Rica. Biomass production costs and dry matterkilogram cost were evaluated in kikuyu grass (Kikuyuocloa clandestina), perennial ryegrass (Lolium perenne) and African stargrass (Cynodon nlemfuensis), along one year, in 8 [...] dairy farms located in Cartago (2), San José (2) and Alajuela (4) provinces. Average dry matter yield per cycle was 3395 kg.ha-1 DM for the three grasses. Annual yield is influenced by the regrowth period of each species, with values of 40 170, 38 731 and 28 995 kg.ha-1 DM for African stargrass, kikuyu grass and perennial ryegrass, respectively. Biomass production varies during the year, and the utilization by cattle has a less utilization of these fields during the months of highest yield. Since the stocking rate, the occupational period and the grazing area are not adjusted an the basis of dry matter availability, dairy cattle has a lower utilization rate in the paddocks. Average costs for labor, agricultural inputs and land were (in Costa Rican currency) 72.433, 505.515 and 18.760 colones.ha-1, respectively. Inputs had the highest impact in the costs structure in grazing dairy farms. Costs for dry matter kilogram produced and consumed were 16.6 and 44.4 colones, respectively, for all 3 pastures; the cost of dry matter-kilogram consumed was affected by the rate of utilization in the grazing paddocks. Dairy farms with higher investment in pastures had a higher return in kg.ha-1 milk as well.

Luis, Villalobos; Jose, Arce; Rodolfo, WingChing.

2013-12-01

354

Ecuaciones alométricas para estimar biomasa y carbono en Quercus magnoliaefolia / Allometric equations for estimating the above-ground biomass and carbon in Quercus magnoliaefolia Née  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish En el ejido El Zapote de la Reserva de la Biosfera "Sierra de Huautla", estado de Morelos, México, se seleccionaron doce árboles de Quercus magnoliaefolia Née y se determinó su biomasa en la parte aérea. El modelo alométrico quedó expresado como: B = 0.0345 * DAP29334 en donde B es la biomasa (kg) y [...] DAP es el diámetro a la altura del pecho (cm), con un coeficiente de determinación (R²= 0.98; P Abstract in english At the El Zapote ejido in the "Sierra de Huautla" Biosphere Reserve in the state of Morelos, Mexico, twelve Quercus magnoliaefolia Née trees were selected and their above-ground biomass determined. The proposed allometric model was expressed as: B = 0.0345 * DBH2.9334, where B is biomass (kg) and DB [...] H is diameter at breast height (cm), with a coefficient of determination (R²= 0.98; PO.001). In addition, above-ground biomass was estimated by a multiple linear regression based on basal area (BA), specific gravity of wood (SGW) and tree height (H). A high proportion of the biomass variation was explained by basal area alone. SGW and H did not significantly increase the accuracy of the models. The average percentage of carbon in Q. magnoliaefolia trees was 47.14 with values of 46.29 % for the bole, 46.83 % for branches and 48.31 % for foliage. The average proportion of the components of the species studied was 62.5 % for the bole, 27.8 % for branches and 9.6 % for foliage.

Jesús D., Gómez-Díaz; Jorge D., Etchevers-Barra; Alejandro I., Monterrosos-Rivas; Julio, Campo-Alvez; Juan A., Tinoco-Rueda.

2011-08-01

355

Gasificación de biomasa residual en el sector floricultor, caso: Oriente Antioqueño / Gasification of waste biomass in the flower industry, case: Eastern Antioquia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Este artículo presenta los resultados de gasificación de una mezcla de 1/3 de cada especie de biomasa residual del cultivo de pompón, áster y hortensia con vapor de agua como agente gasificante, en un reactor a escala de laboratorio. La biomasa, como materia prima recibió un secado solar antes de in [...] iciar el proceso de gasificación, se realizó también un procedimiento de reducción de tamaño de partícula a fin de obtener geometrías acordes al proceso de gasificación, se caracterizó mediante el análisis próximo y último y se estableció como temperatura de operación del reactor un rango de 700 a 750°C. Como resultado, la composición del gas de síntesis producido fue analizada por cromatografía gaseosa y para el promedio de producción se obtienen: CH4 2,8 - 5%v, CO 9,3 - 22,2%v, H2 30,3 - 46,6%v. Abstract in english This paper presents the results of gasification of a mixture of 1/3 of each kind of residual biomass cultivation pompon, hydrangea and aster with steam as a gasifying agent in a laboratory scale reactor. The biomass feedstock received a solar drying before starting the gasification process, there wa [...] s also a method for particle size reduction to obtain consistent geometries with gasification process, was characterized by proximate and ultimate analysis and established as reactor operating temperature range of 700 to 750°C. As a result, the composition of the produced synthesis gas was analyzed by gas chromatography and the average yield obtained: CH4 2.8 to 5%v, CO 9.3 to 22.2%v, H2 30.3 to 46.6%v.

Diego Mauricio, Yepes Maya; Farid, Chejne Janna.

2012-12-01

356

Método basado en teledetección para estimar la emisión de gases efecto invernadero por quema de biomasa / A remote sensing method to estimate greenhouse gas emissions from biomass burning  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish La quema de biomasa es una fuente importante de gases efecto invernadero en países en vías de desarrollo. En Colombia, el cambio de uso del suelo, la silvicultura y el sector agropecuario superan el 50% de las emisiones totales de efecto invernadero. El fuego se utiliza con frecuencia como un mecani [...] smo para cambiar el uso del suelo. Los Llanos orientales y la Amazonía colombiana están sometidos todos los años a la quema de biomasa, especialmente entre enero y marzo. Los estudios en la distribución espacial y temporal de las emisiones son importantes de cara a los informes en el ámbito nacional. Este artículo de revisión describe el método para hacer estas estimaciones utilizando teledetección y algunos de los resultados disponibles para Colombia. Abstract in english Biomass burning is a major source of greenhouse gas emissions in developing countries. In Colombia, land use change, forestry and agriculture are responsible for more than 50% of the total greenhouse gas emissions. Fire is commonly used as a mechanism for land use change. In Colombia the Llanos Orie [...] ntales and the Amazonia are subject to biomass burning every year during the dry season, especially from January to March. Studies of the spatial and temporal distribution of emissions are required for emissions report at a national level. The goal of this state of the art article is to describe a method to estimate emissions with a remote sensing approach and to present some of the variables already measured in Colombia.

Jesús Adolfo, Anaya Acevedo; Emilio, Chuvieco Salinero; Alicia, Palacios-Orueta.

2011-01-01

357

Controlled synthesis of VO{sub 2}(R), VO{sub 2}(B), and V{sub 2}O{sub 3} vanadium-oxide nanowires  

Energy Technology Data Exchange (ETDEWEB)

Vanadium-oxide nanowires (NWs) V{sub 2}O{sub 5}, VO{sub 2}(R), VO{sub 2}(B), and V{sub 2}O{sub 3} are deposited on a substrate to study their field-emission properties. V{sub 2}O{sub 5} NWs are prepared by thermal evaporation via vapor transport of a vanadium-oxide complex under mild conditions. Films of VO{sub 2} and V{sub 2}O{sub 3} wires are subsequently prepared by reducing V{sub 2}O{sub 5} one-dimensional nanocrystals at 450 Degree-Sign C with hydrogen gas. The composition of the flowing H{sub 2}/Ar mixture and the duration of reduction are utilized to control the formation of VO{sub 2}(R) or VO{sub 2}(B) NWs. The crystallinity and morphology of products as prepared are characterized using several techniques, including powder X-ray diffraction, a scanning electron microscope, and a transmission electron microscope. The field-emission properties of the vanadium-oxide NWs as prepared exhibit a turn-on field of 4.56-7.65 V/{mu}m and an emission current density up to 3.68-8.36 mA/cm{sup 2}. These features indicate that vanadium-oxide NWs have potential FE emitter applications.Graphical AbstractV{sub 2}O{sub 5}, VO{sub 2}(R), VO{sub 2}(B), and V{sub 2}O{sub 3} NWs were synthesized via thermal evaporation and controlled reduction process. Field-emission properties of these NWs exhibited turn-on fields of 4-8 V/{mu}m, an emission current density up to 3.5 mA/cm{sup 2}.

Ke, Jhih-Syuan; Weng, Sheng-Feng; Wu, Ming-Cheng; Lee, Chi-Shen, E-mail: chishen@mail.nctu.edu.tw [National Chiao Tung University, Department of Applied Chemistry (China)

2013-07-15

358

Microstructure and Transport properties of epitaxial VO2 thin films on TiO2 substrates  

Science.gov (United States)

Vanadium oxides are paradigms of strongly correlated oxides and have attracted attention because of the metal insulator transitions (MIT) that several of the oxides and sub-oxides exhibit. In particular, VO2 has a metal--semiconductor transition at 340 K. This transition in VO2 combines the properties of a pure Mott Hubbard electronic transition with those of a Peierls structural transition. The Mott transition is responsible for the extreme speed of the optical switching that has been observed (faster than 100 fs). Understanding this transition and how to control it remains a challenge for both theory and experimental physics. We used a novel deposition technique, Reactive Bias Target Ion Beam Deposition, to grow 40 nm epitaxial VO2 thin films on rutile TiO2 substrates with various crystal orientations. X-ray diffraction (XRD) was used to explore the epitaxy of VO2 and we found that all VO2 thin films on TiO2 substrates showed tetragonal symmetry at room temperature due to the constrain from rutile substrates. We also characterized the metal-insulator transition of VO2 films as the function of the crystal orientation of rutile TiO2. We also characterized the anisotropy of VO2 thin films. In collaboration with Kevin West and Stuart Wolf, University of Virginia.

Lu, Jiwei

2008-10-01

359

Structural, photophysical and photocatalytic properties of novel Bi2AlVO7  

International Nuclear Information System (INIS)

Bi2AlVO7 was prepared by solid-state reaction technique for the first time and the structural and photocatalytic properties of Bi2AlVO7 and Bi2InTaO7 were investigated. The results showed that Bi2AlVO7 crystallized in the tetragonal crystal system with space group I4/mmm. In addition, the band gaps of Bi2AlVO7 and Bi2InTaO7 were estimated to be about 2.06 and 2.81 eV. The photocatalytic degradation of aqueous methylene blue (MB) dye with Bi2AlVO7 or Bi2InTaO7 as catalyst was investigated under visible light irradiation. Bi2AlVO7 showed higher photocatalytic activity compared with Bi2InTaO7 for photocatalytic degradation of MB under visible light irradiation. Complete removal of aqueous MB dye was realized after visible light irradiation for 160 min with Bi2AlVO7 as the photocatalyst. The reduction of the total organic carbon (TOC) and the formation of inorganic products, SO42- and NO3- revealed the continuous mineralization of aqueous MB dye during the photocatalytic process. The possible photocatalytic degradation pathway of aqueous MB dye was revealed under visible light irradiation.

360

Pacing strategy and VO2 kinetics during a 1500-m race.  

Science.gov (United States)

We investigated the oxygen uptake response (V.O (2)) to a 1500-m test conducted using a competition race strategy. On an outdoor track, eleven middle-distance runners performed a test to determine V.O (2max), velocity associated with V.O (2max) (v-V.O (2max)) and a supramaximal 1500-m running test (each test at least two days apart). V.O (2max) response was measured with the use of a miniaturised telemetric gas exchange system (Cosmed, K4, Roma, Italy). The 1500-m running test was performed at a mean velocity of 107. 6 + 2 % v-V.O (2max). The maximal value of oxygen uptake recorded during the 1500-m test (V.O (2peak)) was reached by subjects at 75.9 + 7.5 s (mean + SD) (i.e., 459 +/- 59 m). The time to reach V.O (2max) (TV.O (2peak)) and the start velocity (200- to 400-m after the onset of the 1500 m) expressed in % v-V.O (2max) were negatively and significantly correlated (p < 0.05), but our results indicate that a fast start does not necessarily induce a good performance. These results suggest that V.O (2max) is reached by all the subjects at the onset of a simulated 1500-m running event and are therefore in contrast with previous results obtained during treadmill running. PMID:17990206

Hanon, C; Leveque, J-M; Thomas, C; Vivier, L

2008-03-01

 
 
 
 
361

Reinvestigation of the synthesis of LiFeVO{sub 4}  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} We reinvestigated the synthesis of the LiFeVO{sub 4} compound. {yields} We demonstrate that the recently reported LiFeVO{sub 4} phase is not a pure phase. {yields} We proved by Rietveld refinement that LiFeVO{sub 4} is a mixture ofLiVO{sub 3} and Fe{sub 2}O{sub 3}. {yields} We noticed some attempts to fraud (modification of the powder pattern) . - Abstract: The synthesis of LiFeVO{sub 4} composition has been performed in air starting from Li{sub 2}CO{sub 3}, Fe{sub 2}O{sub 3}, and V{sub 2}O{sub 5} 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 LiFeVO{sub 4} samples. The powder pattern has been perfectly indexed using the single crystal data of LiVO{sub 3} (C2/c, a = 10.16718 A, b = 8.415725 A, c = 5.884155 A and {beta} = 110.489{sup o}) and {alpha}-Fe{sub 2}O{sub 3} (R-3c, a = 5.035 A, c = 13.75 A).

Yahia, Hamdi Ben, E-mail: benyahia.hamdi@aist.go.jp [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Shikano, Masahiro; Tatsumi, Kuniaki [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

2011-07-15

362

Handover Management for VoWLAN Based on Estimation of AP Queue Length and Frame Retries  

Science.gov (United States)

Switching a communication path from one Access Point (AP) to another in inter-domain WLANs is a critical challenge for delay-sensitive applications such as Voice over IP (VoIP) because communication quality during handover (HO) is more likely to be deteriorated. To maintain VoIP quality during HO, we need to solve many problems. In particular, in bi-directional communication such as VoIP, an AP becomes a bottleneck with the increase of VoIP calls. As a result, packets queued in the AP buffer may experience a large queuing delay or packet losses due to increase in queue length or buffer overflow, thereby causing the degradation of VoIP quality for the Mobile Nodes (MNs) side. To avoid this degradation, MNs need to appropriately and autonomously execute HO in response to the change in wireless network condition, i.e., the deterioration of wireless link quality and the congestion state at the AP. In this paper, we propose an HO decision strategy considering frame retries, AP queue length, and transmission rate at an MN for maintaining VoIP quality during HO. Through simulation experiments, we then show that our proposed method can maintain VoIP quality during HO by properly detecting the wireless network condition.

Niswar, Muhammad; Kashihara, Shigeru; Tsukamoto, Kazuya; Kadobayashi, Youki; Yamaguchi, Suguru

363

Experimental Analysis of VoIP over Wireless Local Area Networks  

Directory of Open Access Journals (Sweden)

Full Text Available

VoIP is a rapidly growing technology that enables the transport of voice over data networks such asthe public Internet. VoIP became a viable alternative to the public switched telephone networks (PSTNs. In parallel, a dramatic increase is happening in the deployment of Wireless Local Areas Networks (WLAN in buildings and corporate campuses. Nowadays, WLAN is mostly used for ordinary data services such as web browsing, file transfer and electronic mail. However, with the emerging usage of VoIP telephony, WLAN are sought to be used as an access infrastructure for enabling such applications. One of the issues of using VoIP over WLAN is the effects caused by users roaming within and between WLAN subnets during a VoIP session. The latency and the jitter are greatly impacted when the control of the mobile node is handed over from one access point (AP to another one. This poses a challenge to providing and preserving QoS for VoIP users in WLAN environments. In this paper, we propose to study and measure the effect of the handover for both intra and inter mobility for VoIP traffic.

Mohammed Boulmalf

2007-06-01

364

Study on the QoE for VoIP Networks  

Directory of Open Access Journals (Sweden)

Full Text Available In recent years, people are recognizing that the quality in VoIP application should be evaluated according to the QoE (Quality of Experience. The main goal of this paper is to analyze the different factors on the impact of voice quality for VoIP networks. Our contributions are thus threefold: First, we establish a new VoIP simulation platform. The network simulation software is WANem, the voice communication protocol is implemented by Open Phone. This simulation system is more ‘real’ than other researcher’s system. Secondly, we analyze the factors that affect the voice quality of VoIP networks. Thirdly, we use the VoIP networks simulation platform to test the network performance impact on the quality of voice service. Through the experiment result, we can conclude that in order to get the better voice quality, we use the iLBC codec when the VoIP network is exist packet loss. And use the AMR 12.2 kb/s when the VoIP network is exist time delay

Weiwei Zhang

2014-02-01

365

EPR and UV studies of VO2+ ions in potassium D-gluconate monohydrate single crystals  

International Nuclear Information System (INIS)

Electron paramagnetic resonance (EPR) of VO2+ doped potassium hydrogen D-gluconate single crystals and powder have been examined at room temperature. Single crystal rotations in each of the three mutually orthogonal crystalline planes namely ac, ba and ca indicate two different VO2+ complexes. Each complex is located in different chemical environments, each environment containing two magnetically inequivalent VO2+ sites in distinct orientations occupying substitutional positions in the lattice and showing a very large angular dependence. The powder spectrum also clearly indicates four different VO2+ complexes, confirming the single crystal analysis. Crystalline field around the VO2+ ion is nearly axial. The optical absorption spectrum of VO2+ ions in the crystal lattice is also studied at room temperature. The characteristic spectrum of the VO2+ ions has two absorption bonds. The bond positions are at 17 857 and 11 235 cm-1. Spin Hamiltonian parameters and molecular orbital coefficients are calculated from the EPR and the optical data, and results are discussed.

366

Size effects in the structural phase transition of VO2 nanoparticles studied by surface-enhanced Raman scattering  

Science.gov (United States)

We report the first experimental application of surface-enhanced Raman scattering (SERS) to the study of the structural phase transition of vanadium dioxide (VO2). Using arrays of gold-capped VO2 nanoparticles (Au+VO2 NPs) and a VO2 film covered with Au islands, we obtained the temperature evolution of the SERS intensity with respect to the amount of accessible material across the monoclinic-tetragonal-monoclinic transformation cycle of VO2. The smallest Au+VO2 NPs displayed the largest deviations from the bulk transition temperatures to complete the transformation, resulting in the widest thermal hysteresis, while the Au+VO2 film exhibited the narrowest hysteresis. The observed size dependence agrees qualitatively with the model of defect-induced nucleation of the VO2 transition, although the magnitude of the hysteresis width and its dependence on NP size were less pronounced than those in a previous study of elastic light scattering from bare VO2 NPs. The discrepancies may stem from the creation of extrinsic nucleation sites in the VO2 NPs during their high-temperature processing in the presence of the Au caps; alternatively, the hystereses of the structural and electronic transitions could each have a different dependence on size. Lastly, we correlate the size dependence of the VO2 SERS intensity with the scattering efficiency of the Au nanoparticles, within the framework of a modified Mie-theory calculation.

Donev, E. U.; Ziegler, J. I.; Haglund, R. F., Jr.; Feldman, L. C.

2009-12-01

367

Fabrication and efficient visible light-induced photocatalytic activity of Bi2WO6/BiVO4 heterojunction  

International Nuclear Information System (INIS)

The Bi2WO6/BiVO4 photocatalyst with heterojunction structure was synthesized. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicated that Bi2WO6 nanoplate was loaded on the BiVO4 surface. UV–vis diffusion absorption spectra (DRS) displayed no obvious difference between the band gap absorption edges of the BiVO4 and Bi2WO6/BiVO4. It was found that the phenol degradation rate with Bi2WO6/BiVO4 was 2.55 times as great as that with the BiVO4 under visible light (? > 400 nm) by the photocatalytic measurements. The enhanced photocatalytic performance of the Bi2WO6/BiVO4 sample was attributed to the improved separation efficiency of photogenerated hole–electron pairs generated by the heterojunction between Bi2WO6 and BiVO4. -- Highlights: ? The Bi2WO6/BiVO4 photocatalyst with heterojunction structure was synthesized. ? Bi2WO6/BiVO4 showed better photocatalytic performance than BiVO4 under visible light. ? The improved separation rate of h+ and e? leaded to the enhanced photocatalytic ability.

368

Morphology-dependent photocatalytic removal of NO by hierarchical BiVO4 microboats and microspheres under visible light  

International Nuclear Information System (INIS)

In this study, hierarchical monoclinic BiVO4 three-dimensional (3D) superstructures with two kinds of morphologies, namely BiVO4 microboats and BiVO4 microspheres, have been controllably synthesized by adjusting reaction time in the template-free hydrothermal process using ethylene glycol as solvent. The nucleation, growth, and self-assembly of the BiVO4 superstructures could be readily controlled with reaction time, which brought different morphologies to the final product. The as-prepared BiVO4 superstructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption experimentation, and UV-vis diffuse reflectance spectra (UV-vis DRS). The monoclinic 3D BiVO4 catalysts are composed of two-dimensional (2D) nanoplates which intercross with each other. Nanoplates were firstly formed by aggregation of primary nanocrystallites and then self-assembly converted to microboats and microspheres via the oriented attachment mechanism. The prepared BiVO4 3D catalysts can respond to visible light and their optical and photocatalytic properties are relevant to their morphologies. The BiVO4 microspheres showed superior photocatalytic activity on removal of gaseous NO compared to the BiVO4 microboats. The morphology-dependent photocatalytic property of the BiVO4 superstructures is discussed. This work suggests that the synthesized BiVO4 micropheres are promising photocatalyst for environmental remediation.

369

Ruminal degradation of aerial biomass and seeds of wild species of Lupinus / Degradación ruminal de semillas y biomasa aérea de especies silvestres de Lupinus  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish La degradación ruminal de la materia seca (DMS) y de la proteína cruda (DPC) en biomasa aérea durante la etapa de floración, y en las semillas de L. campestris, L. exaltatus, L. hintonii y L. montanus fue determinada mediante la técnica de la bolsa de nylon, con dos bovinos machos fistulados, en cin [...] co tiempos de incubación (3, 9, 12, 24 y 48 h), incluyendo una muestra de pasta de soya (PS). Los datos obtenidos se analizaron usando PROC MIXED de SAS para medidas repetidas. Los resultados mostraron interacción entre especie y tiempo de incubación para DMS y DPC de la biomasa aérea y semillas. Entre especies de lupino, alta DMS y DPC de las semillas se observó desde las 3 h de incubación. A las 48 h la DMS y DPC no mostró variación significativa entre especies. DMS fluctuó de 94,3 a 96,7% y la DPC de 98,9 a 99,2%. La tasa de degradación de la fracción insoluble de la MS (kd) en semillas de lupino varió de 6,3 a 8,1% h-1; y la fracción soluble (FS) de 42,3 a 57,3%; valor inferior al de PS. La DMS y DPC de la biomasa aérea mostró diferencias estadísticas significativas entre especies a las 48 h de incubación. L. hintonii con la menor DMS (69,6%) y DPC (88,9%). Para la DPC, L. campestris y L. montanus mostraron las menores kd y FS en biomasa aérea (kd de 5,4% h-1 en ambas y 35,4 y 37,2 para FS, respectivamente) y una alta DPC. Se concluye que las semillas y la biomasa aérea de las especies silvestres de lupino presentan alta degradabilidad de la MS y PC desde las 3 h de incubación, mostrando solo diferencias estadísticas significativas entre ellas a las 48 h para la DMS y DPC de la biomasa aérea (BA). L. campestris y L. exaltatus fueron las especies que mostraron la más alta DMS y DPC de la BA y la más baja de las semillas. Abstract in english Ruminal degradation of dry matter (DMD) and crude protein (CPD) for aerial biomass at the flowering stage and for the seeds of L. campestris, L. exaltatus, L. hintonii and L. montanus was determined using the nylon bag technique with two fistulated steers in five incubation times (3, 9, 12, 24 and 4 [...] 8 h), including a sample of soybean paste (SP). The data obtained were analyzed using PROC MIXED of SAS for repeated measures. The results showed interactions between species and incubation time for DMD and CPD. Among species of lupine, a high DMD and CPD of seeds were observed after three hours of incubation. At 48 h, DMD and CPD did not show significant variation between species: DMD ranged from 94.3% to 96.7% and CPD from 98.9 to 99.2%. The degradation rate of the insoluble fraction of the DM (kd) in lupine seeds ranged from 6.3 to 8.1% h-1, while that of the soluble fraction (SF) ranged from 42.3 to 57.3%, lower value that observed in SP. The DMD and CPD of aerial biomass showed statistically significant differences between species at 48 h of incubation. L. hintonii showed the lowest DMD (69.6%) and CPD (88.9%). L. montanus and L. campestris showed a lower SF and kd (kd of 5.4% h-1 in both, and 35.4 and 37.2 for SF, respectively) and high CPD of aerial biomass. It is concluded that the DM and CP of seeds and biomass of wild lupine were highly degradable as of 3 h of incubation. At 48 h, there were statistically significant differences between DMD and CPD of aboveground biomass (AGB). L. campestris and L. exaltatus showed the highest DMD and CPD of AGB and similar DMD and CPD of seeds.

Maricela, Pablo-Pérez; Luz del C, Lagunes-Espinoza; Jesús, Ramos-Juárez; Javier, López-Upton; Emilio M, Aranda-Ibáñez; Luis, Vargas-Villamil.

2014-04-01

370

Synthesis and photocatalytic performances of BiVO4 by ammonia co-precipitation process  

International Nuclear Information System (INIS)

This paper reports the preparation and photocatalytic performance of Bismuth vanadate (BiVO4) by a facile and inexpensive approach. An amorphous BiVO4 was first prepared by a co-precipitation process from aqueous solutions of Bi(NO3)3 and NH4VO3 using ammonia. Followed by heating treatment at various temperatures, the amorphous phase converted to crystalline BiVO4 with a structure between monoclinic and tetragonal scheelite. The crystallization of BiVO4 occurred at about 523 K, while the nanocrystalline BiVO4 were formed with a heat-treatment of lower than 673 K. However, when the heat-treatment was carried out at 773 K, the accumulation of nanocrystals to bulk particles was observed. The photocatalytic performances of the materials were investigated by O2 evolution under visible-light, and MB decomposition under solar simulator. The results demonstrated that the crystalline structure is still the vital factor for the activities of both reactions. However, the crystallinity of BiVO4 gives a major influence on the activity of O2 evolution, whereas the surface area, plays an important role for photocatalytic MB decomposition. - Abstract: BiVO4 was prepared by a co-precipitation process using aqueous ammonia solution, followed by heating treatment at various temperatures. The crystalline structure and crystallization process, and tructure and crystallization process, and their influences on photocatalytic O2 evolution and organic pollutants degradation were investigated. It demonstrated that the crystalline structure is still the vital factor for the activities of both reactions. However, the crystallinity of BiVO4 gives a major influence on the activity of O2 evolution, whereas the surface area, plays an important role for photocatalytic MB decomposition. Display Omitted

371

Preparation of Co-BiVO4 Photocatalyst and Its Application in the Photocatalytic Oxidative Thiophene  

Directory of Open Access Journals (Sweden)

Full Text Available The Co-BiVO4 photocatalyst was prepared by hydrothermal method and characterized by X-ray diffraction, scanning electron microscope, UV-Vis absorption spectroscope, and low-temperature N2 adsorption. The characterized results indicate that highly crystalline monoclinic scheelite structure of Co-BiVO4 is obtained at pH=7 and the Co dopant does not change the crystal phase of BiVO4. The Co-BiVO4 has a significant red-shift in the absorption band in the visible region, and its absorption intensity increases greatly for the doped catalyst compared with pure BiVO4. Low-temperature N2 adsorption result reveals that the pore size of the Cu-BiVO4(pH=7 mostly distributes at 2.67 nm. The desulfurization ability of Co-BiVO4 was researched by photocatalytic oxidation of thiophene in visible light. The results show that the Co-BiVO4 photocatalysts exhibit higher photocatalytic activities for degradation of thiophene under visible light irradiation. When pH value is 7.0 and the hydrothermal synthesize time is 8 h, the photocatalytic activities reach the maximum. Under the conditions of 150 mL/min air flow, 1.0 mg/L catalyst amount, and visible light irradiation for 3 h in 400 W xenon lamp light, the desulfurization rate by Co-BiVO4 at 600 mg/L initial concentration increases to 86%.

GAO Xiao-Ming, FU Feng, WU Yu-Fei, ZHANG Li-Ping, LI Wen-Hong

2012-10-01

372

Efficient High Power Ho,Tm:GdVO4 Laser  

International Nuclear Information System (INIS)

We report a 22.3 W cw diode-pumped cryogenic Ho(0.5at.%),Tm(at.5%):GdVO4 laser at a wavelength of 2.05 ?m. It is pumped by two fiber-coupled laser diodes with a fiber core diameter of 0.4 mm, both of which provide 42 W pump power near 802 nm. A cw output power of 22.3 W was obtained at the pump power of 51.0 W, corresponding to an optical-to-optical conversion efficiency of 43.7% when the ratio of the pump beam to oscillating laser beam in the crystal was ?1.33:1. The M2 factor was found to be 2.0 under an output power of 16.5 W. (fundamental areas of phenomenology(including applications))

373

Zircon to monazite phase transition in CeVO4  

CERN Document Server

X-ray diffraction and Raman-scattering measurements on cerium vanadate have been performed up to 12 and 16 GPa, respectively. Experiments reveal that at 5.3 GPa the onset of a pressure-induced irreversible phase transition from the zircon to the monazite structure. Beyond this pressure, diffraction peaks and Raman-active modes of the monazite phase are measured. The zircon to monazite transition in CeVO4 is distinctive among the other rare-earth orthovanadates. We also observed softening of external translational Eg and internal B2g bending modes. We attributed it to mechanical instabilities of zircon phase against the pressure-induced distortion. We additionally report lattice-dynamical and total-energy calculations which are in agreement with the experimental results. Finally, the effect of non-hydrostatic stresses on the structural sequence is studied and the equations of state of different phases are reported.

Panchal, V; Santamaria-Perez, D; Errandonea, D; Manjon, F J; Rodriguez-Hernandez, P; Munoz, A; Achary, S N; Tyagi, A K

2011-01-01

374

Influence of dimensionality on phase transition in VO2 nanocrystals  

Directory of Open Access Journals (Sweden)

Full Text Available Hydrothermally synthesized one-dimensional and two-dimensional nanocrystals of VO2 undergo phase transition around 65°C, where temperature and mechanism of phase transition are dependent on dimensionality of nanocrystals. Both nanocrystalline samples exhibit depression of phase transition temperature compared to the bulk material, the magnitude of which depends on the dimensionality of the nanocrystal. One-dimensional nanoribbons exhibit lower phase transition temperature and higher values of apparent activation energy than two-dimensional nanosheets. The phase transition exhibits as a complex process with somewhat lower value of enthalpy than the phase transition in the bulk, probably due to higher proportion of surface atoms in the nanocrystals. High values of apparent activation energy indicate that individual steps of the phase transition involve simultaneous movement of large groups of atoms, as expected for single-domain nanocrystalline materials. [Projekat Ministarstva nauke Republike Srbije, br. 142015

Blagojevi? V.A.

2013-01-01

375

N-type ferrimagnetism of SmVO3  

International Nuclear Information System (INIS)

DC and AC magnetizations of the perovskite ortho-vanadate compound SmVO3 with GdFeO3 structure were investigated by a SQUID magnetometer. The low field cooled magnetic susceptibility became negative between 68 and 122 K, and the negative remanent and spontaneous magnetizations were confirmed at 90 K with cooling fields below 10 kOe. These results are discussed on the basis of the molecular field theory for the N-type ferrimagnetism of V3+ magnetic moments. By the present analysis, the ferrimagnetic transition temperature of Tc=130 K, and the inter- and intra-sublattice exchange integrals of JAB/kB=-62.5 K, JAA/kB=-16.2 K and JBB/kB=-13.8 K were obtained

376

A structured approach to VO reconfigurations through Policies  

CERN Document Server

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

Reiff-Marganiec, Stephan

2012-01-01

377

Electrical control of terahertz nano antennas on VO2 thin film.  

Science.gov (United States)

We demonstrate an active metamaterial device that allows to electrically control terahertz transmission over more than one order of magnitude. Our device consists of a lithographically defined gold nano antenna array fabricated on a thin film of vanadium dioxide (VO(2)), a material that possesses an insulator to metal transition. The nano antennas let terahertz (THz) radiation funnel through when the VO(2) film is in the insulating state. By applying a dc-bias voltage through our device, the VO(2) becomes metallic. This electrically shorts the antennas and therefore switches off the transmission in two distinct regimes: reversible and irreversible switching. PMID:22108973

Jeong, Young-Gyun; Bernien, Hannes; Kyoung, Ji-Soo; Park, Hyeong-Ryeol; Kim, Hyun-Sun; Choi, Jae-Wook; Kim, Bong-Jun; Kim, Hyun-Tak; Ahn, Kwang Jun; Kim, Dai-Sik

2011-10-24

378

VO2+-hydroxyapatite complexes as models for vanadyl coordination to phosphate in bone  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe a 1D and 2D ESEEM investigation of VO2+ adsorbed on hydroxyapatite (HA) at different concentrations and compare with VO2+-triphosphate (TPH) complexes studied previously in detail, in an effort to provide more insight into the structure of VO2+coordination in bone. Structures of this interaction are important because of the role of bone in the long-term storage of administered vanadium, and the likely role of bone in the steady-state release of vanadium leading to the chronic insu...

Dikanov, Sergei A.; Liboiron, Barry D.; Orvig, Chris

2013-01-01

379

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

Science.gov (United States)

Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercise time during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderate exercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longer exercise time at VO2max. Six subjects (mean ± SD; age: 22.9±4.5 yr; height: 181.2±7.1 cm and body mass: 75.5±3.4 kg) completed square-wave transitions to 100% of VO2max from three different conditions: without prior exercise, with prior moderate and heavy exercise. VO2 was measured using a telemetric portable gas analyser (K4b(2), Cosmed, Rome, Italy) and the data were modelled using either mono or double exponential fittings. The use of prior moderate exercise resulted in a faster VO2 pulmonary kinetics response (?1?=?13.41±3.96 s), an improved performance in the time to exhaustion (238.8±50.2 s) and similar blood lactate concentrations ([La(-)]) values (11.8±1.7 mmol.L(-1)) compared to the condition without prior exercise (16.0±5.56 s, 215.3±60.1 s and 10.7±1.2 mmol.L(-1), for ?1, time sustained at VO2max and [La(-)], respectively). Performance of prior heavy exercise, although useful in accelerating the VO2 pulmonary kinetics response during a subsequent time to exhaustion exercise (?1?=?9.18±1.60 s), resulted in a shorter time sustained at VO2max (155.5±46.0 s), while [La(-)] was similar (13.5±1.7 mmol.L(-1)) compared to the other two conditions. Although both prior moderate and heavy exercise resulted in a faster pulmonary VO2 kinetics response, only prior moderate exercise lead to improved rowing performance. PMID:24404156

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

2014-01-01

380

Study on the QoE for VoIP Networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In recent years, people are recognizing that the quality in VoIP application should be evaluated according to the QoE (Quality of Experience). The main goal of this paper is to analyze the different factors on the impact of voice quality for VoIP networks. Our contributions are thus threefold: First, we establish a new VoIP simulation platform. The network simulation software is WANem, the voice communication protocol is implemented by Open Phone. This simulation system is more ‘real&rs...

Weiwei Zhang; Yongyu Chang; Yitong Liu; Atif Hameed; Yuan Tian

2014-01-01

 
 
 
 
381

VoIP Session Capacity Expansion with Packet Transmission Suppression Control in Wireless LAN  

Science.gov (United States)

This paper proposes a VoIP (Voice over Internet Protocol) session capacity expansion method that uses periodic packet transmission suppression control for wireless LANs. The proposed method expands the VoIP session capacity of an AP without critically degrading the QoS (Quality of Service) of all stations. Simulation results show the proposed method with 0.5% packet suppression control on each station expands a VoIP session capacity by up to 5% compared to a legacy method while satisfying required QoS for all stations.

Morioka, Yasufumi; Higashino, Takeshi; Tsukamoto, Katsutoshi; Komaki, Shozo

382

Performance Analysis of Statistical Distributions for VoIP over WiMAX Access Networks  

Directory of Open Access Journals (Sweden)

Full Text Available Statistical distributions are used to represent behavior of real VoIP traffic. This paper investigates the performance of VoIP traffic over WiMAX networks by examining statistical comparison of interarrival time distribution. The parameters are used to analyze the Quality of Service (QoS, like delay, jitter, throughput with respect to Voice Activity Detection (VAD or Silence Detection (SD in voice codec G.729. The simulation result indicates that the pareto distribution in interarrival time has a significant impact on the performance of VoIP in WiMAX network.

Gysberth Maurits Wattimena

2013-04-01

383

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transmission of VoIP over packet switching networks is one of the rapidly emerging real-time Internet Protocol. The real-time application of the Voice over Internet Protocol (VoIP) is growing rapidly for it is more flexible than the traditional Public Switched Telephone Networks systems (PSTN). Meanwhile, the VoIP deployment on Wireless Local Area Networks (WLANs), which is based on IEEE 802.11 standards, is increasing. Currently, many schedulers have been introduced such as Weighted Fair Que...

Kashif Nisar; Abas Md Said,; Halabi Hasbullah

2011-01-01

384

VoIP Performance with Aggressive AMC and SINR Feedback for WiMAX Downlink  

Science.gov (United States)

WiMAX system is based on OFDMA, and it is very suitable for VoIP traffic. At the same time, aggressive AMC and frame bundling are two important techniques to improve the performance of VoIP, and so they are applied to WiMAX system in this paper. The simulation results show that when the system is in short of bandwidth, these two techniques indeed reduce the PER and delay jitter of the VoIP users, and also enhance the spectrum efficiency.

Fan, Xiangning; Dengkui, Zhu

385

Labeled VoIP Data-set for Intrusion Detection Evaluation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VoIP has become a major application of multimedia communications over IP. Many initiatives around the world focus on the detection of attacks against VoIP services and infrastructures. Because of the lack of a common labeled data-set similarly to what is available in TCP/IP network-based intrusion detection, their results can not be compared. VoIP providers are not able to contribute their data because of user privacy agreements. In this paper, we propose a framework for customizing and gener...

Nassar, Mohamed; Radu, State; Festor, Olivier

2010-01-01

386

Epitaxial growth and characterization of CaVO3 thin films  

International Nuclear Information System (INIS)

Epitaxial thin films of CaVO3 were synthesized on SrTiO3, LaAlO3 and (La0.27Sr0.73)(Al0.65Ta0.35)O3 substrates by pulsed laser deposition. All CaVO3 films, independent of epitaxial strain, exhibit metallic and Pauli paramagnetic behavior as CaVO3 single crystals. X-ray absorption measurements confirmed the 4+ valence state for Vanadium ions. With prolonged air exposure, an increasing amount of V3+ is detected and is attributed to oxygen loss in the near surface region of the films.

387

Instantaneous Band Gap Collapse in Photoexcited Monoclinic VO2 due to Photocarrier Doping  

Science.gov (United States)

Using femtosecond time-resolved photoelectron spectroscopy we demonstrate that photoexcitation transforms monoclinic VO2 quasi-instantaneously into a metal. Thereby, we exclude an 80 fs structural bottleneck for the photoinduced electronic phase transition of VO2 . First-principles many-body perturbation theory calculations reveal a high sensitivity of the VO2 band gap to variations of the dynamically screened Coulomb interaction, supporting a fully electronically driven isostructural insulator-to-metal transition. We thus conclude that the ultrafast band structure renormalization is caused by photoexcitation of carriers from localized V 3 d valence states, strongly changing the screening before significant hot-carrier relaxation or ionic motion has occurred.

Wegkamp, Daniel; Herzog, Marc; Xian, Lede; Gatti, Matteo; Cudazzo, Pierluigi; McGahan, Christina L.; Marvel, Robert E.; Haglund, Richard F.; Rubio, Angel; Wolf, Martin; Stähler, Julia

2014-11-01

388

Comparación de un reactor de biomasa suspendida y un reactor de biomasa adherida para la biodegradación de compuestos tóxicos presentes en aguas residuales de refinerías de petróleo / Biodegradation of toxic compounds from oil refinery wastewater: comparison of two batch reactors with suspended and attached biomass  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Esta investigación comprende un estudio de tratamiento de aguas residuales de una refinería utilizando dos rectores biológicos discontinuos secuenciales (SBR, por sus siglas en inglés Sequencing Batch Reactor). El primero de ellos es un reactor de biomasa suspendida y el segundo es un reactor de bio [...] masa adherida, en el cual se utilizaron soportes plásticos tipo Kaldnes K1. Debido a la diversidad y complejidad de las aguas residuales de refinerías, fue necesario aclimatar los microorganismos utilizando la estrategia de eficiencias fijas para garantizar una buena degradación de los compuestos difícilmente biodegradables o recalcitrantes. Los reactores operaron durante 45 días empleando ciclos de 24 h (llenado, tiempo de reacción, sedimentación, vaciado y tiempo muerto). La carga orgánica volumétrica aplicada a los reactores varió entre 0.44 - 0.54 kg DQO/m³ d; las cargas orgánicas superficiales oscilaron entre 1.56 - 1.80 g DQO/m² d para el reactor de biomasa adherida. El desempeño de los reactores discontinuos secuenciales se evaluó mediante las eficiencias de remoción de DQO, COD y fenoles, obteniendo porcentajes de remoción de 75, 73 y 99 % en el reactor de biomasa suspendida, mientras que en el reactor de biomasa adherida se alcanzaron porcentajes de remoción de 77, 81 y 99 %, respectivamente. La concentración de sólidos suspendidos totales en el reactor de biomasa suspendida fue de aproximadamente 2200 mg SST/L mientras que en el reactor de biomasa adherida se registró entre 450 y 560 mg SST/L. La relación SSV/SST se mantuvo entre 0.8 y 1 en ambos reactores. La concentración de biomasa adherida a los soportes osciló entre 3.98 gST/m² y 5.45 gST/m². En cada reactor se realizaron cuatro perfiles para evaluar la capacidad de los microorganismos para degradar el tipo sustrato al que fueron expuestos en un tiempo determinado. En ambos reactores, los perfiles de degradación 1 y 2 mostraron que la máxima remoción de DQO se presentó durante la primera hora de reacción, mientras que para los perfiles 3 y 4 la máxima remoción se alcanzó después de la segunda hora. En el caso de los fenoles, en todos los perfiles se obtuvo una remoción de más del 98 % durante la primera hora de reacción, indicando que en ambos reactores la biomasa fue capaz de degradar los compuestos tóxicos presentes en las aguas desflemadas sin importar el tipo de aglomeración microbiana utilizada. Abstract in english This study deals with the treatment of an oil refinery's wastewater using two sequencing batch reactors. The first one was a suspended biomass reactor and the second was an attached biomass reactor with Kaldnes K1 carriers. Due to the diversity and complexity of the refinery wastewater, it was neces [...] sary to acclimate the microorganisms using fixed efficiency strategy to ensure a good degradation of the poorly biodegradable or recalcitrant compounds. The reactor operated for 45 days using 24 h cycles (filling, reaction time, settle, draw and idle). The volumetric organic loading applied to both reactors ranged between 0.44 and 0.54 kg COD/m³d; the surface loads ranged between 1.56 - 1.80 g COD/m² d for the attached biomass reactor. The performance of the sequencing batch reactors was assessed by the efficiency of COD removal, DOC and phenols content, obtaining final removal percentages of75, 73 and 99 % in the suspended biomass reactor, while the attached biomass reactor reached removal percentages of 77, 81 and 99 %, respectively. The total suspended solids concentration in the reactor suspended biomass was approximately 2200 mg TSS/L while in the attached biomass reactor was between 450 and SST 560 mg/L. The VSS/TSS ratio was 0.8 and 1 for both reactors. The concentrations of biomass attached ranging from 3.98 g/m² to 5.45 g/m². In each reactor were made four profiles for assessing the ability of microorganisms to degrade type substrate to which they were exposed in a given time. In both reactors, degradation pro

Lizet Marina, NAVA URREGO; Raquel, GASPERÍN SANCHÉZ; Alfonso, DURÁN MORENO.

2014-02-01

389

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

Energy Technology Data Exchange (ETDEWEB)

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

Kouchri, Farrokh Mohammadzadeh

2012-11-06

390

Biomasa de raíces en un bosque templado con y sin manejo forestal en Hidalgo, México / Root biomass in a temperate forest with and without forest management in Hidalgo, Mexico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish Las raíces son buenos indicadores funcionales del ecosistema ya que constituyen gran parte de la biomasa viva del suelo y ejercen un control sobre los procesos de pedogénesis, la producción de materia orgánica y la dinámica de los nutrientes. En este trabajo se comparó la biomasa de raíces gruesas y [...] finas entre un bosque conservado y un bosque con manejo forestal de corte selectivo. La biomasa promedio de raíces no difirió significativamente entre sitios (P = 0.185). La biomasa en el bosque con manejo forestal fue de 3.05 Mg·ha-1 (E. E. = 0.25) y de 3.39 Mg·ha-1 (E. E. = 0.24) en el bosque conservado. Las raíces finas ocuparon el mayor porcentaje de la biomasa en ambos tipos de bosque, aunque sus valores no difirieron significativamente entre sitios (P = 0.095). De acuerdo con los resultados, al parecer, el manejo forestal de tipo de corte selectivo mantiene las condiciones ambientales y en particular del suelo, lo que permite contener una biomasa similar a la de un bosque conservado bajo condiciones naturales. Abstract in english The effect of forest management on biodiversity and ecosystem processes has been little studied in Mexican temperate forests. In this way, roots are good functional indicators of an ecosystem because they constitute much of the living ground biomass and exert control over soil formation processes, o [...] rganic matter production and nutrient dynamics. This study compares coarse and fine root biomass from a protected forest and a managed area where there was selective logging during 2003 and 2004, resulting in the removal of 10 % of the trees. The average root biomass did not differ significantly between sites (P = 0.185). Root biomass in the managed forest was 3.05 Mg·ha¹ (S.E. = 0.25) and 3.39 Mg·ha-1 (S.E. = 0.24) in the preserved forest. Fine roots occupied the highest percentage of the biomass in both forest types, although their values did not differ significantly between sites (P = 0.095). As the results suggest, selective logging maintains environmental conditions, particularly those of the soil, which allows having similar biomass to that in the forest preserved under natural conditions.

Numa P., Pavón; Claudia E., Moreno; Aurelio, Ramírez-Bautista.

2012-12-01

391

Superionic conductors in the Bi2WO6 - Bi2VO5.5 system  

International Nuclear Information System (INIS)

Bi2VxW1-xO6-y ceramics are synthesized, and their structure and electrical properties are