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Sample records for na biomasa vo

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

    DEFF Research Database (Denmark)

    Karydis, D.A.; Boghosian, S.

    2002-01-01

    Red-brown crystals of a new mixed alkali oxo sulfato vanadium(V) compound Na2K6(VO)(2)(SO4)(7), suitable for X-ray determination, have been obtained from the catalytically important binary molten salt system M2S2O7-V2O5 (M = 80% K and 20% Na). By slow cooling of a mixture with the mole fraction X-V2O5 = 0.24 from 325 degreesC, i.e., just below the liquidus temperature, to the solidus temperature of around 300 degreesC, a dark reddish amorphous phase was obtained containing crystals of the earlier described V(V)-V(IV) mixed valence compound K-6(VO)(4)(SO4)(8) and Na2K6-(VO)(2)(SO4)(7) described here. This compound crystallizes in the tetragonal space group P4(3)2(1)2 (No. 96) with a = 9.540(3) Angstrom, c = 29.551(5) Angstrom at 20 degreesC and Z = 4. It contains a distorted VO6 octahedron with a short V-O bond of 1.552(6) Angstrom, a long one of 2.276(5) Angstrom trans to this, and four equatorial V-O bonds in the range 1.881(6)-1.960-(6) A. The deformation of the VO6 octahedron is less pronounced compared tothat of the known oxo sulfato V(V) compounds. Each VO3+ group is coordinated to five sulfate groups of which two are unidentately coordinated and three are bidentate bridging to neighboring VO3+ groups. The length of the S-O bonds in the S-O-V bridges of the two unidentately coordinated sulfato groups are 1.551(6) Angstrom and 1.568(6) Angstrom, respectively, which are unusually long compared to our earlier measurements of sulfate groups in other V(111), V(IV), and V(V) compounds.

  2. AC conductivity and dielectric behavior of polyaniline/sodium metavenadate (PANI/NaVO3) composites

    International Nuclear Information System (INIS)

    The conducting polyaniline/sodium metavenadate (PANI/NaVO3) composites were synthesized by single step in situ polymerization technique by placing finely grinded powder of NaVO3 during the polymerization of aniline. The formation of mixed phases of the polymer together with the conducting emeraldine salt phase was confirmed by spectroscopic techniques like FTIR. SEM images indicated a systematic morphological variation of particles aggregated in the composite matrix as compared to the pristine PANI. AC conductivity and dielectric behavior of these composites were investigated in the frequency range 50 Hz to 5 MHz. It is found that AC conductivity obeyed the power law index and the variation of conductivity with wt% of NaVO3 could be related to conductivity relaxation phenomenon. These composites have shown high dielectric constant, which is related to polarization. It is seen that both dielectric constant and dielectric loss decrease with increase in frequency. Variations in measured parameters of AC response with increasing frequency of these composites are found to follow systematic trends that are similar to those observed with temperature and doping.

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

    DEFF Research Database (Denmark)

    Karydis, D.A.; Boghosian, S.; Nielsen, Kurt; Eriksen, Kim Michael; Fehrmann, Rasmus

    2002-01-01

    Red-brown crystals of a new mixed alkali oxo sulfato vanadium(V) compound Na2K6(VO)(2)(SO4)(7), suitable for X-ray determination, have been obtained from the catalytically important binary molten salt system M2S2O7-V2O5 (M = 80% K and 20% Na). By slow cooling of a mixture with the mole fraction X-V2O5 = 0.24 from 325 degreesC, i.e., just below the liquidus temperature, to the solidus temperature of around 300 degreesC, a dark reddish amorphous phase was obtained containing crystals of the earlie...

  4. Successive orbital ordering transitions in NaVO_2

    Energy Technology Data Exchange (ETDEWEB)

    Klimczuk, Tomasz W [Los Alamos National Laboratory; Mcqueen, T [PRINCETON U.; Stephens, P W [STONY BROOK U.; Huang, Q [NIST CENTER FOR NEUTRON; Ronning, Filip [Los Alamos National Laboratory; Cava, R [PRINCETON U.

    2008-01-01

    Temperature-dependent dc susceptibility, heat capacity, and x-ray and neutron diffraction measurements on powder samples of the layered triangular-lattice material NaY02 reveal two successive phase transitions. At high temperature the structure is rhomobohedral, with all six inplane V-V distances equivalent. At T = 98K, the system undergoes a second order phase transition to a monoclinic intermediate temperature phase in which the in-plane Y -Y distances separate into four short and two long bonds, corresponding to orbital ordering of one electron per y3+. Below T 93K, there is a first order phase transition to a low temperature monoclinic phase, in which there are four long and two short in-plane Y -Y distances, consistent with orbital ordering of two electrons per y 3+ on a triangular lattice. Long range magnetic ordering of 0.98(2),uB per y 3 + (3d2) sets in at the T 93K structural transition. The low temperature structure ofNa Y02 displays orbital ordering that, although predicted by first principle calculations, has not previously been observed in this class of materials.

  5. Neutron and X-ray diffraction studies on the high temperature phase of Mn{sub 3}(VO{sub 4}){sub 2}, the new isostructural compound NaMn{sub 4}(VO{sub 4}){sub 3} and their mixed crystals Na{sub x}Mn{sub 4.5-x/2}(VO{sub 4}){sub 3} (0{<=}x{<=}1)

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Oliver [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany); Haberkorn, Robert [Universitaet des Saarlandes, Anorganische Festkoerperchemie, Am Markt, Zeile 3, 66125 Saarbruecken (Germany); Springborg, Michael [Universitaet des Saarlandes, Physikalische und Theoretische Chemie, Campus B2 2, 66123 Saarbruecken (Germany); Beck, Horst Philipp, E-mail: hp.beck@mx.uni-saarland.de [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany)

    2012-10-15

    This paper presents a detailed structure analysis (combined Rietveld analysis of X-ray and neutron powder diffraction data as well as quantum mechanical calculations) of the high temperature phase of Mn{sub 3}(VO{sub 4}){sub 2} (space group I4 Macron 2d). Special attention is directed to the analysis of the local coordination around Mn{sup 2+} ions or vacancies within a stella quadrangula configuration of anions. Furthermore, the new compound NaMn{sub 4}(VO{sub 4}){sub 3} is described as well as a range of mixed crystals between NaMn{sub 4}(VO{sub 4}){sub 3} and Mn{sub 3}(VO{sub 4}){sub 2} (described by the formula Na{sub x}Mn{sub 4.5-x/2}(VO{sub 4}){sub 3}, 0{<=}x{<=}1) which were synthesized by a solid state route. All compounds were shown to be isostructural to the high temperature phase Mn{sub 3}(VO{sub 4}){sub 2}. - Graphical abstract: The crystal structure of the new compound NaMn{sub 4}(VO{sub 4}){sub 3}. Highlights: Black-Right-Pointing-Pointer We present neutron and X-ray diffraction studies on high temperature-Mn{sub 3}(VO{sub 4}){sub 2}. Black-Right-Pointing-Pointer Structural details of partly filled stellae quadrangulae positions are discussed. Black-Right-Pointing-Pointer Refined structural parameters and theoretical calculations are compared. Black-Right-Pointing-Pointer We investigate the mixed crystal system Mn{sub 3}(VO{sub 4}){sub 2}-NaMn{sub 4}(VO{sub 4}){sub 3}.

  6. Neutron and X-ray diffraction studies on the high temperature phase of Mn3(VO4)2, the new isostructural compound NaMn4(VO4)3 and their mixed crystals NaxMn4.5?x/2(VO4)3 (0?x?1)

    International Nuclear Information System (INIS)

    This paper presents a detailed structure analysis (combined Rietveld analysis of X-ray and neutron powder diffraction data as well as quantum mechanical calculations) of the high temperature phase of Mn3(VO4)2 (space group I4¯2d). Special attention is directed to the analysis of the local coordination around Mn2+ ions or vacancies within a stella quadrangula configuration of anions. Furthermore, the new compound NaMn4(VO4)3 is described as well as a range of mixed crystals between NaMn4(VO4)3 and Mn3(VO4)2 (described by the formula NaxMn4.5-x/2(VO4)3, 0?x?1) which were synthesized by a solid state route. All compounds were shown to be isostructural to the high temperature phase Mn3(VO4)2. - Graphical abstract: The crystal structure of the new compound NaMn4(VO4)3. Highlights: ? We present neutron and X-ray diffraction studies on high temperature-Mn3(VO4)2. ? Structural details of partly filled stellae quadrangulae positions are discussed. ? Refined structural parameters and theoretical calculations are compared. ? We investigate the mixed crystal system Mn3(VO4)2–NaMn4(VO4)3.

  7. Tunable emission, energy transfer and charge compensation in Sr3(VO4)2:Sm(3+),P(5+),Na(+) phosphor.

    Science.gov (United States)

    Cao, Renping; Peng, Dedong; Xu, Haidong; Jiang, Shenhua; Fu, Ting; Luo, Wenjie; Luo, Zhiyang

    2015-11-01

    A series of Sr3(VO4)2:Sm(3+),P(5+),Na(+) phosphors are synthesized by using solid-state reaction method in air. The strongest emission band peaking at ?600nm is assigned to the (4)G5/2?(6)H7/2 transition of Sm(3+) ion, and the strong excitation peak at ?402nm due to (6)H5/2?(4)F7/2 transition indicates that these phosphors can be excited by near ultraviolet light emitting diode chip. Energy transfer (ET) between VO4(3-) group and Sm(3+) ion can be observed. Sr3(VO4)2:Sm(3+) phosphor with excitation 320nm exhibits a systematically varied hues from green to yellow by changing Sm(3+) ion concentration from 0 to 6mol%. The luminous mechanism of Sr3(VO4)2:Sm(3+) phosphor is explained by using the energy level diagrams of VO4(3-) group and Sm(3+) ion. The luminescence properties of Sr3(VO4)2:Sm(3+) phosphor can be improved and tuned by codoping the P(5+) and Na(+) ions due to ET and charge compensation. Lifetimes of Sr2.925Sm0.05(VO4)2, Sr2.925Sm0.05(V0.9P0.1O4)2, and Sr2.9Na0.05Sm0.05(V0.9P0.1O4)2 phosphors are 1.208, 1.219, and 0.796ms, respectively. The experiment results are helpful to adjust the luminescence properties of Sm(3+)-doped other phosphors. PMID:26067936

  8. Cinética do VO2 durante o exercício realizado na potência crítica em ciclistas e indivíduos não-treinados no ciclismo / VO2 Kinetics during exercise performed at critical power in cyclists and untrained individuals

    Scientific Electronic Library Online (English)

    Renato Aparecido Corrêa, Caritá; Camila Coelho, Greco; Dalton Müller, Pessôa Filho.

    2013-06-01

    Full Text Available O objetivo foi analisar a cinética do consumo de oxigênio (VO2) na potência crítica (PC), em indivíduos com diferentes níveis de aptidão aeróbia no ciclismo. Seis ciclistas treinados (GT) e sete indivíduos não-treinados (GNT) realizaram os seguintes protocolos em cicloergômetro: (a) progressivo até [...] a exaustão para determinação do VO2max e sua respectiva intensidade (IVO2max); (b) três testes em cargas constantes até a exaustão a 95-110%IVO2max para determinação da PC; e (c) um teste em carga constante até a exaustão a 100%PC. No exercício a 100%PC, o componente lento expresso em valor absoluto (GT: 342,4±165,8 ml.min-1 vs. GNT: 571,3±170,1 ml.min-1) e relativo ao aumento do VO2 em exercício (GT: 10,0±4,6% vs. GNT: 26,6±7,3%) foram menores para GT. O VO2 ao final do exercício (GT: 89,8±8,4%VO2max vs. GNT: 97,4±2,8%VO2max) foi significativamente menor no grupo GT (? = 0,045), sendo similar ao VO2max no grupo GNT. Portanto, o nível de aptidão aeróbia pode influenciar as respostas do VO2 ao exercício em PC. Abstract in english The objective was to analyze the oxygen uptake (VO2) kinetics during exercise performed at critical power (CP) in subjects with different aerobic status in cycling. Six trained cyclists (GT) and seven non-trained subjects (GNT) underwent to the following protocols in cyclergometer: (a) incremental t [...] o exhaustion to determine VO2max and its respective workload (IVO2max); b) three square-wave tests to exhaustion at 95-110% IVO2max to determine CP, and; (c) one square-wave test to exhaustion at 100%CP. During the exercise at CP the slow component expressed as absolute value (GT: 342.4±165.8 ml.min-1 vs. GNT: 571.3±170.1 ml.min-1) and as the relative contribution to the increase of VO2 during exercise (GT: 10.0±4.6% vs. GNT: 26.6±7.3%) were lower for trained subjects. The VO2 at the end of the exercise at PC (GT: 89.8±8.4%VO2max vs. GNT: 97.4±2.8%VO2max) was significantly lower in GT (? = 0.045), and similar to VO2max in GNT. Therefore, the aerobic level might influence the VO2 responses to exercise at PC.

  9. 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)

    Leonardo, De Lucca; Sebastião Iberes Lopes, Melo.

    Full Text Available 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

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

    OpenAIRE

    Fabrizio Caputo; Camila Coelho Greco; Benedito Sérgio Denadai

    2005-01-01

    OBJETIVO: Determinar os efeitos do estado e especificidade de treinamento aeróbio na relação entre o percentual do consumo máximo de oxigênio (%VO2max) e o percentual da frequência cardíaca máxima (%FCmax) durante o exercício incremental realizado no cicloergômetro. MÉTODOS: Sete corredores, 9 ciclistas, 11 triatletas e 12 sedentários, todos do sexo masculino e aparentemente saudáveis, foram submetidos a um teste incremental até a exaustão no cicloergômetro. Regressões lineares entre %VO2max ...

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

    International Nuclear Information System (INIS)

    The hot corrosion of sprayed Fe-40 (at.%)Al intermetallic alloy with additions of boron and alumina whiskers in molten NaVO3 at 700 deg. C has been evaluated by potentiodynamic polarization curves and electrochemical impedance spectroscopy, EIS, techniques. For short exposure times, the corrosion mechanism under these conditions was observed to be controlled by an activation process, whereas for longer exposure times, the corrosion process was under diffusion control due to the growing of an Al2O3 oxide scale, which made the diffusion of both reducing and oxidizing species through the scale to the alloy or scale surfaces more difficult. Equivalent electric model used to simulate the EIS data showed that a finite length Warburg diffusion could properly characterize the diffusion process, which confirmed the formation of a compact corrosion product scales containing rich aluminium oxide. Thus, the corrosion process was under diffusion control of aggressive ions through the formed scale. The electrochemical study was complemented by scanning electronic microscopy characterization and micro chemical analysis.

  12. Reprodutibilidade do VO2Máx estimado na corrida pela frequência cardíaca e consumo de oxigênio de reserva / Reliability of VO2Max estimated in treadmill running by heart rate reserve and power output

    Scientific Electronic Library Online (English)

    Tony Meireles, Santos; Bruno Ferreira, Viana; Alberto Souza, Sá Filho.

    2012-03-01

    Full Text Available Objetivou-se comparar os efeitos de utilização da frequência cardíaca máxima medida (FCpico) vs. predita (FC Predita) na estimativa do VO2Máx em esteira pelo método de FC e VO2 de reserva. Dezoito homens (27,5 ± 7,1 anos, 73,7 ± 12,6 kg, 174,8 ± 10,2 cm) realizaram na primeira visita um teste progre [...] ssivo máximo para determinar a FCpico. Nas duas visitas seguintes foram realizados os testes aeróbios submáximos em esteira com estágio de 6 min a 75% da FC de reserva. O VO2Máx foi estimado pelo uso conjunto das equações de FC, VO2 de reserva e equação de corrida do ACSM. Não foi observada diferença significativa (teste t) entre as estimativas de VO2Máx a partir da FCpredita e FCpico. O coeficiente de correlação intraclasse e erro típico da medida utilizando FCpredita e FCpico foram 0,89, 2,43 mL.kg-1.min-1 (5%) e 0,83, 2,43 mL.kg-1.min-1 (4,9%), respectivamente. O uso da abordagem estimada para determinação da FC máxima mostrou-se adequado para a determinação do VO2Máx com um pequeno erro típico da medida. Abstract in english The objective was to determine the reliability of the VO2Max estimate on a treadmill using the measured (HRpeak) vs. the predicted (HRpredicted) maximum heart rate (HR). Eighteen men (27.5 ± 7.1 years, 73.7± 12.6 kg, 174.8 ± 10.2 cm) performed, in the first visit, a progressive test to determine the [...] HRpeak. In the two following visits, submaximal aerobic tests were performed on a treadmill with a 6 min at 75% HR reserve. VO2Max was estimated by means of the equations of HR, VO2 reserve and the ACSM running equation. The intraclass correlation coefficient and the typical error of measurement using HRPredicted and HRpeak were 0.89, 2.43 ml.kg-1.min-1 (5%) and 0.83, 2.43 mL.kg-1.min-1 (4.9%), respectively. There was no significant difference (t test) between the estimates of VO2Max from the HRpeak and HRpredicted. The use of the HRpredicted was considered appropriate for VO2Max estimation, with a small typical error of measurement.

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

    Scientific Electronic Library Online (English)

    Fabrizio, Caputo; Camila Coelho, Greco; Benedito Sérgio, Denadai.

    2005-01-01

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

  14. Near-infrared downconversion through host sensitized energy transfer in Yb3+-doped Na2YMg2(VO4)3

    Science.gov (United States)

    Li, Yong; Wei, Xiantao; Chen, Hongmei; Pan, Yan; Ji, Yuexia

    2015-12-01

    Host sensitized near-infrared emitting phosphor Na2YMg2(VO4)3:Yb3+ was fabricated by a sol-gel method. Efficient broad emission is observed under ultraviolet excitation ranging from 240 nm to -400 nm and this luminescence originates from ligand-metal charge transfer of 2p of O2- to 3d of V5+. Under excitation of ultraviolet light in the broad absorption band, intense near-infrared emission of Yb3+ around 974 nm is observed for Yb3+-doped Na2YMg2(VO4)3. Through study of photoluminescence spectra, fluorescence decay curves and concentration-dependent luminescence, mechanism of energy transfer from VO4 group to Yb3+ was proposed to rationalize the downconversion process. This phosphor with performance of ultra-violet to near-infrared downconversion could have potential application in improving efficiency of silicon-based solar cell.

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

    Scientific Electronic Library Online (English)

    Paulo Henrique Silva Marques de, Azevedo; João Carlos de, Oliveira; Herbert Gustavo, Simões; Vilmar, Baldissera; Sérgio Eduardo de Andrade, Perez.

    2010-08-01

    Full Text Available Foi investigada a influência do gênero no tempo limite (Tlim) e na cinética do VO2 durante corrida na velocidade associada ao VO2max (vVO2max) em nove homens e nove mulheres, todos adultos, jovens e sedentários, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolan [...] te, sendo um teste incremental para determinar VO2max (42,66 ± 4,50 vs. 32,92 ± 6,03mL.kg-1.min-1) e vVO2max (13.2 ± 1.5 vs. 10,3 ± 2,0km.h-1), respectivamente. Um segundo teste com carga constante na vVO2max até a exaustão. O Tlim e a cinética do VO2 foram determinados. Não houve diferença significante entre homens e mulheres para constante de tempo (?) (35,76 ± 21,03 vs. 36,5 ± 6,21s, respectivamente; P = 0,29); Tlim (308 ± 84,3 vs. 282,11 ± 57,19s, respectivamente; P = 0,68), tempo para atingir o VO2max (TAVO2max) (164,48 ± 96,73 vs. 167,88 ± 28,59s, respectivamente; P = 0,29), tempo para atingir o VO2max em percentual do Tlim (%Tlim) (50,24 ± 16,93 vs. 62,63 ± 16,60%, respectivamente; P = 0,19), tempo mantido no VO2max (TMVO2max) (144,08 ± 42,55 vs. 114,23 ± 76,96s, respectivamente; P = 0,13). Estes resultados sugerem que a cinética do VO2 e o Tlim são similares entre homens e mulheres sedentários na vVO2max. Abstract in english The aim of this study was to investigate the influence of gender on Tthre and VO2 response during running exercise performed at vVO2max. Therefore, eighteen untrained individuals (9 male and 9 female) with normal weight and aged between 20 - 30 years (VO2max = 42.66 ± 4.50 vs 32.92 ± 6.03 mL.kg-1.mi [...] n-1 and vVO2max = 13.2 ± 1.5 vs 10.3 ± 2.0 km.h-1, for male and female, respectively) were assessed. Subjects performed two exercise tests on treadmill. First one was an incremental test to determine VO2max, velocity at VO2max (vVO2max) and second test was performed at steady velocity - vVO2max - until exhaustion. The threshold time (Tthre) and VO2 kinetics response was determined. No significant differences were observed between men and women for time constant (?) (35.76 ± 21.03 vs 36.5 ± 6.21s, respectively; P = 0.29); Tthre (308 ± 84.3 vs 282.11 ± 57.19s, respectively; P = 0.68), time to achieve VO2max (TAVO2max) (164.48 ± 96.73 vs 167.88 ± 28.59s, respectively; P = 0.29), time to achieve VO2max in Tthre percentage (%Tthre) (50.24 ± 16.93 vs 62.63 ± 16.60%, respectively; P = 0.19); time maintained at VO2max (TMVO2max) (144.08 ± 42.55 vs 114.23 ± 76.96s, respectively; P = 0.13). These results suggest that the VO2 kinetics response and Tthre is similar between untrained men and women at the vVO2max.

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

    OpenAIRE

    Paulo Henrique Silva Marques Azevedo; João Carlos de Oliveira; Herbert Gustavo Simões; Vilmar Baldissera; Sérgio Eduardo de Andrade Perez

    2010-01-01

    Foi investigada a influência do gênero no tempo limite (Tlim) e na cinética do VO2 durante corrida na velocidade associada ao VO2max (vVO2max) em nove homens e nove mulheres, todos adultos, jovens e sedentários, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolante, sendo um teste incremental para determinar VO2max (42,66 ± 4,50 vs. 32,92 ± 6,03mL.kg-1.min-1) e vVO2max (13.2 ± 1.5 vs. 10,3 ± 2,0km.h-1), respectivamente. Um segundo teste com carga constante...

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

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos Silva

    1999-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Victor Machado Reis

    2013-12-01

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

  19. 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)

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

    2013-12-01

    Full Text Available 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%.

  20. Calefaccion centralizada por biomasa, Cuéllar

    Directory of Open Access Journals (Sweden)

    Verdú Pérez, Jesús

    2001-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2013-03-01

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

  2. 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

    Scientific Electronic Library Online (English)

    Fabiana Andrade, Machado; Benedito Sérgio, Denadai.

    2013-03-01

    Full Text Available O consumo máximo de oxigênio (VO2máx) é a quantidade máxima de energia que pode ser produzida pelo metabolismo aeróbio em determinada unidade de tempo, podendo ser determinado direta ou indiretamente através de equações preditivas. O objetivo deste trabalho foi elaborar uma equação preditiva específ [...] ica 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. Abstract in english 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.

  3. 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)

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

    2013-12-01

    Full Text Available INTRODUÇÃO E OBJETIVOS: Investigar se a inclusão do equivalente energético de lactato sanguíneo (LS) em intensidades submáximas alteraria o gasto energético de corrida (Gc) estimado para corrida supramáxima de alta intensidade assim como sua precisão MÉTODOS: O Gc foi determinado a partir da curva 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.

  4. VoIP Security

    OpenAIRE

    Fontanini, Piero

    2008-01-01

    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....

  5. 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)

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

    2008-10-08

    Full Text Available 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 significant differences between stations and months. Using a gr

  6. Benefícios do Uso do VoIP: um estudo de caso na GMBenefits from the VOIP Use: a case study at GMBeneficios del Uso del VoIP: un estudio de caso en la GM

    Directory of Open Access Journals (Sweden)

    FEITERA, Carlos Henrique

    2006-05-01

    Full Text Available RESUMOEste artigo traz uma visão do que é o VoIP, assim como suas principais aplicações, os fatores que as empresas buscam para minimizar custos em telefonia, as vantagens e desvantagens, a agregação de novas tecnologias, como WI-FI e o VOIP, e o futuro da telefonia no Brasil.Serão analisadas as diferenças entre Telefonia IP e VOIP paralelamente, e será tratada como base e estudo de caso a empresa General Motors do Brasil. O objetivo é mostrar o conteúdo que envolve essa inovadora tecnologia. Podemos dizer que a vontade de abordar esse tema foi despertada não somente por ser uma tecnologia inovadora que vem substituindo a telefonia convencional reduzindo os custos das empresas e trocando serviços e equipamentos obsoletos por uma série de novos serviços e oferecendo muitos recursos e benefícios, mas nos chamou a atenção também pelo fato de ser uma tecnologia que está revolucionando o mercado de telecomunicações, já que as empresas de telefonia prestadoras de serviços consomem uma boa parte da renda das empresas e pessoas, e também por exigir, nesse período de transição, muita habilidade em adequar as necessidades do cliente ao uso dessas ferramentas.ABSTRACTThis article brings a vision about Voip, as well as itself main applications, the factors with that the companies search to decrease costs in telephony, the advantages and disadvantages, aggregation of new technologies as wi-fi to the VOIP and the future of the telephony in Brazil. The differences between Telephony IP and VOIP will be analyzed parallel, and will be showed with as base study case of the General Motors. Our objective for this subject is to show the content that involves this fantastic technology. We can say that will to approach this subject it was influenced not only by being an innovative technology that comes substituting the conventional telephony, reducing the costs of the companies, and changing to services and obsolete equipments for a series of new services offering many resources and benefits, but it also called-us the attention for the fact being a technology whom making a revolution in telecommunications market where the rendering companies of telephony of services consumes a good part of the income of the companies and people, and also for This article brings a vision about VOIP, as well as its main applications, the factors with that the companies search to decrease costs in telephony, the advantages and disadvantages, aggregation of new technologies as wi-fi to the VOIP and the future of the telephony in Brazil. The differences between Telephony IP and VOIP will be analyzed in parallel, and will be showed having as base a case study of the General Motors. Our objective for this subject is to show the content that involves this fantastic technology. We can say that the will to approach this subject was influenced not only by being an innovative technology that comes to substitute the conventional telephony, reducing the costs of the companies, and changing services and obsolete equipment for a series of new services offering many resources and benefits, but it also called us the attention for the fact that this is a technology making a revolution in telecommunications market where the rendering companies of telephone services consumes a good part of the income of the companies and people, and also for demanding in this period of transition a great deal of ability to adequate the necessities of the customer to use of these tools and resources.RESUMENEste artículo aporta una visión de lo que es el VoIP, sus principales aplicaciones, los factores que las empresas buscan para minimizar costos en telefonía, las ventajas y desventajas, el agregado de nuevas tecnologías, como WI-FI y el VOIP y el futuro de la telefonía en Brasil.Se analizarán las diferencias entre Telefonía IP y VOIP y se tratará como base y estudio de caso la empresa General Motors de Brasil. La finalidad es mostrar el contenido que comprende esta innovadora tecnología. Podemos decir que el interés en este tema surgió prim

  7. Solid Biomass Consumption in Households and Greenhouse Gas Emission Reduction in Latvia / CIET?S Biomasas PAT?RI?Š un SILTUMN?CEFEKTA G?ZU Emisiju SAMAZIN?ŠANAS PERSPEKT?VA Latvijas M?JSAIMNIEC?B?S

    Science.gov (United States)

    Kudrenickis, I.; Klavs, G.

    2013-12-01

    Utilisation of biomass is an important factor in reducing emission of greenhouse gases (GHG); at the same time, high efficiency of biomass combustion technologies is to be ensured to minimise the methane (CH4) emission thus achieving the most efficient reduction in the total GHG emission. The authors analyse the GHG emission breakdown in Latvia among the sectors not included in the EU Emissions Trading Scheme (ETS), and, in the context of emission reduction, evaluate the energy supply in the Latvian household sector, the types of combustion technologies and the used fuels. The trend is considered for the CH4 emission factor during 1990-2010 in the household sector of EU countries, and the numerical index is calculated which illustrates decoupling the consumption of biomass fuel from CH4 emission. To evaluate the perspective of CH4 emission reduction in the Latvian household sector, two scenarios are investigated for efficiency improvement as related to the central heating equipment based on wood fuel. Biomasas izmantošana ir viens no principi?lajiem virzieniem siltumn?cefekta g?zu (SEG) emisiju samazin?šan?. Maksim?la SEG emisiju samazin?juma pan?kšanai ir nepieciešams nodrošin?t biomasas sadedzin?šanas iek?rtu augstu efektivit?ti, lai minimiz?tu ar biomasas kurin?m? pat?ri?u saist?to met?na (CH4) emisiju pieaugumu. Autori raksturo Eiropas Savien?bas (ES) Emisiju kvotu tirdzniec?bas sist?mas (ETS) un taj? neietilpstošo sektoru (ne-ETS) noz?mi Latvijas SEG emisiju veidošan?, SEG emisiju relat?vo sadal?jumu atbilstoši daž?diem ne- ETS sektoriem un SEG emisiju samazin?šanas kontekst? analiz? Latvijas m?jsaimniec?bu sektora energoapg?di, pat?r?to kurin?mo un izmantot?s kurin?m? sadedzin?šanas tehnolo?ijas. Rakst? ir demonstr?ta SEG emisiju inventariz?cij? pielietot? CH4 emisiju specifisk? faktora m?jsaimniec?bu sektora koksnes kurin?majam skaitlisko v?rt?bu dinamika 1990-2010 gados daž?d?s ES valst?s. Sal?dzinot kurin?m? pat?ri?a un CH4 emisiju apjoma izmai?as, ir apr??in?ts skaitliskais r?d?t?js, kas raksturo biomasas kurin?m? pat?ri?a un CH4 emisiju "atsaisti" ES valst?s analiz?jam? laika posm?. Lai kvantitat?vi nov?rt?tu CH4 emisiju samazin?šanas perspekt?vu Latvijas m?jsaimniec?bu sektor?, autori analiz? divus att?st?bas scen?rijus, kas paredz daž?dus m?jsaimniec?bu centr?laj? apkur? izmantoto koksnes sadedzin?šanas iek?rtu efektivit?tes pieaugumus.

  8. ECUACIONES ALOMÉTRICAS PARA ESTIMAR BIOMASA Y CARBONO EN Quercus magnoliaefolia

    Directory of Open Access Journals (Sweden)

    Jesús D. Gómez-Díaz

    2011-01-01

    Full Text Available 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 * DAP2.9334 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<0.001. Adicionalmente, se estimó la biomasa mediante una regresión lineal múltiple que consideró el área basal (AB, la densidad específica de la madera (DEM y la altura de los árboles (H. Una alta proporción de la varianza de la biomasa fue explicada solamente por el área basal. La DEM y H no incrementaron significativamente la precisión de los modelos. El porcentaje promedio de carbono en los árboles de Q. magnoliaefolia fue de 47.14 con valores de 46.29 % para el fuste, 46.83 % para las ramas y 48.31 % para el follaje. La proporción promedio de los componentes de la especie estudiada fue de 2.5 % para el fuste, 27.8 % para las ramas y 9.6 % para el follaje.

  9. Utjecaj alkohola na u?inak u zadatku sljepo?e zbog nepažnje u simuliranoj situaciji vožnje automobila

    Directory of Open Access Journals (Sweden)

    Andro Pavuna

    2012-05-01

    Full Text Available Akutna konzumacija etilnoga alkohola štetno utje?e na brojne vidne funkcije. U ovom smo se istraživanju usredoto?ili na specifi?ne procese vidne percepcije i pažnje te utjecaj relativno niskih razina alkohola na njih. U istraživanju je sudjelovalo 47 studenata raznih fakulteta Sveu?ilišta u Zagrebu. Sudionici u eksperimentalnoj skupini (N=22 konzumirali su alkoholni koktel stopostotnoga naran?inog soka i votke kako bi dostigli ciljanu razinu alkohola u krvi od 0.8 g/kg, dok su sudionici u kontrolnoj skupini (N=25 konzumirali placebo – samo naran?in sok sa snažnom aromom etilnoga alkohola. Nakon konzumacije pi?a sudionici su rješavali zadatak vidne percepcije i pažnje koji se sastojao od kratkoga video-isje?ka koji prikazuje režiranu realnu prometnu situaciju u kojoj jedno vozilo slijedi drugo s centralnim zadatkom brojanja paljenja ''štop'' svjetala na vozilu koje se kre?e ispred njega, te percepcije zna?ajnih objekata i detalja iz okoline poput dje?jih kolica, djeteta koje prelazi cestu, prometnih zakova i sl. Provedenim je istraživanjem utvr?eno kako sudionici pod utjecajem alkohola postižu statisti?ki zna?ajno slabiji rezultat u zadatku vidne percepcije od sudionika koji nisu pod utjecajem alkohola. Dobiven je umjereni efekt u kumulativnom zadatku vidne percepcije i pažnje, te nezna?ajan, ali jasan trend štetnoga utjecaja alkohola na pojedine zadatke vidne percepcije i pažnje.

  10. Latest VO developments at Paris VO Data Center

    Science.gov (United States)

    Le Sidaner, P.; Dubernet, M.-L.; Simon, G.; Aboudarham, J.; Baillard, A.; Barache, C.; Boone, F.; Chilingarian, I.; Dantel-Fort, M.; Desert, J. M.; Didelon, P.; Egret, D.; Guibert, J.; Hebrard, G.; Lainey, V.; Magnard, F.; Marmo, C.; Martin, J. M.; Pelat, D.; Renié, C.; Sarkissian, A.; Schneider, J.; Theureau, G.; Vachier, F.

    2006-06-01

    Paris VO Data Center aims at providing VO access to its databases ressources, at participating to international standards developments, at implementing VO compliant simulation codes and data visualisation and analysis softwares. We will present some of the latest VO developments involving ressources from Paris VO Data Center, i.e, the first simple spectra access for data of the Nançay radiotelescope observatory, a validator for Simple Spectra Access protocols and its implementation tools, a Cone-search access to the exoplanet catalog, a pipeline for images processing to make them "science-ready" in vo-format, implementation of Simple Image Access using Geographic Information System in databases. Developments involving other ressources may be found in their own contributions to this meeting.

  11. Latest VO development at VO-Paris Data Centre

    Science.gov (United States)

    Le Sidaner, P.; Dubernet, M.-L.; Simon, G.; Aboudarham, J.; Baillard, A.; Barache, C.; Boone, F.; Chilingarian, I.; Dantel-Fort, M.; Didelon, P.; Egret, D.; Guibert, J.; Hebrard, G.; Lainey, V.; Magnard, F.; Marmo, C.; Martin, J. M.; Normand, J.; Pelat, D.; Renié, C.; Sarkissian, A.; Savalle, R.; Shih, A.; Schneider, J.; Theureau, G.; Vachier, F.

    2007-07-01

    VO-Paris Data Center aims at providing VO access to its databases resources, at participating to the development of interoperability standards, at implementing VO-compliant simulation codes and data visualization and analysis software. We will present some of the latest VO development involving resources from Paris VO Data Center, i.e, the first simple spectral access for data of the Nancay radio-telescope, a validator for Simple Spectra Access protocols and its implementation tools, a Cone-search access to the exoplanet catalog, a pipeline for image processing to make them "science-ready" and converting into VO-format, implementation of Simple Image Access using Geographic Information System in databases. Developments involving other resources may be found in their own contributions to this meeting.

  12. EFECTO DEL CARBONATO DE POTASIO EN LA EVOLUCIÓN DE LOS GRUPOS FUNCIONALES DE LOS BIOCRUDOS DE CONVERSIÓN HIDROTÉRMICA DE BIOMASA LIGNOCELULÓSICA ALREDEDOR DEL PUNTO CRÍTICO DEL AGUA / POTASSIUM CARBONATE EFFECT ON BIOCRUDE FUNCTIONAL GROUPS EVOLVING FROM LIGNOCELLULOSIC BIOMASS UNDERGOING HYDROTHERMAL CONVERSION CLOSE TO THE CRITICAL POINT OF WATER / EFEITO DO CARBONATO DE POTÁSSIO NA FORMAÇÃO DOS GRUPOS FUNCIONAIS DOS BIOPETRÓLEOS OBTIDOS POR CONVERSÃO HIDROTÉRMICA DE BIOMASSA LENHOCELULÓSICA PRÓXIMO DO PONTO CRÍTICO DA ÁGUA

    Scientific Electronic Library Online (English)

    Alejandro A, Castro; Andrés, Anzola; Iván, Cagua; Luis I, Rodríguez; Yazmín, Agámez; Orlando, Hernández; José de J, Díaz.

    2008-08-01

    Full Text Available Um tipo de biomassa pobre em lenhina, do género Pennisetum, foi submetido ao processo de conversão hidrotérmica na presença de carbonato de potássio como catalisador. As reacções foram conduzidas em condições próximas do ponto crítico da água. Os produtos de reacção não aquosos (biopetróleo) foram s [...] eparados por decantação e analisados por espectroscopia de infravermelho. Os biopetróleos obtidos contêm compostos com funcionalidades aromáticas, olefínicas, hidroxiladas, éteres e, no caso do biopetróleo obtido sob condição subcrítica, funções carbonilo. A fracção gasosa e a quantidade de biopetróleo aumentam na presença de carbonato de potássio. Abstract in spanish Un tipo de biomasa pobre en lignina, del género Pennisetum, fue sometida al proceso de conversión hidrotérmica en presencia de carbonato de potasio como catalizador. Las reacciones se llevaron a cabo en ambientes cercanos al punto crítico del agua. Los productos de reacción no acuosos (biocrudo) se [...] separaron por decantación y se analizaron por espectrometría infrarroja. Los biocrudos obtenidos contienen compuestos con funcionalidades aromáticas, olefínicas, hidroxiladas, éteres, y para el caso del biocrudo obtenido bajo la condición subcrítica funciones carbonilo. La fracción gaseosa y el biocrudo aumentan en presencia del carbonato de potasio. Abstract in english A type of poor-lignin biomass (Pennisetum sp.) was hydrothermally converted in the presence of potassium carbonate as catalyst. The reactions were carried out close to the critical point of the water. The non-aqueous (biocrude) reaction products were separated by decantation and were analyzed by inf [...] rared spectrometry. The biocrude products so obtained contained compounds having aromatic, olephinic, hydroxylated and ether functionalities; sub-critical biocrude had carbonyl functions. The gaseous and biocrude fractions increased in the presence of potassium carbonate.

  13. 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)

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

    2009-08-01

    Full Text Available 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

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

    Directory of Open Access Journals (Sweden)

    Pedro A. Rodr\\u00EDguez

    2007-01-01

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

  15. La biomasa en la producción de electricidad en España

    Directory of Open Access Journals (Sweden)

    Espejo Marín, Cayetano

    2005-06-01

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

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

  16. VoWiFi Roaming

    OpenAIRE

    Muhammad Ali, Syed

    2006-01-01

    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 c...

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

    Scientific Electronic Library Online (English)

    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.

    Full Text Available 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.

  18. 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)

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

    Full Text Available 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.

  19. 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

    Directory of Open Access Journals (Sweden)

    Lizet Marina NAVA URREGO

    2014-01-01

    Full Text Available 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 biomasa 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/m 3 d; las cargas orgánicas superficiales oscilaron entre 1.56 - 1.80 g DQO/m 2 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 concen - tración 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/m 2 y 5.45 gST/m 2 . En cada reactor se realizaron cuatro perfiles para evaluar la capacidad de los microorganismos para degradar el tipo sustrato al que fueron ex - puestos 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

  20. Biomasa de rotíferos de dos embalses con diferentes estados tróficos (Antioquia, Colombia y su relación con algunas variables limnológicas

    Directory of Open Access Journals (Sweden)

    Silvia L Villabona-González

    2014-12-01

    Full Text Available 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 temperatura, 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.

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

    Directory of Open Access Journals (Sweden)

    Lizet Rodr\\u00EDguez-Mach\\u00EDn

    2014-01-01

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

  2. Investigation of VoIP and implementation

    OpenAIRE

    Ede, Aghedo

    2011-01-01

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

  3. VoIP Technology: Security Issues Analysis

    OpenAIRE

    Lazzez, Amor

    2013-01-01

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

  4. VO2 films as active infrared shutters

    OpenAIRE

    Johansson, Daniel

    2006-01-01

    An active optical shutter for infrared light (3-5 ?m) has been designed, exploiting the phase transition in thermochromic vanadium dioxide (VO2). A spin coating processing route for VO2 films has been adapted to manufacture reproducible depositions onto sapphire (Al2O3) substrates. The VO2 films have been characterized by X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR), showing 55 % transmittance in the open mode and 0.1 % in the closed mode. The VO2 film temperature determin...

  5. New phases in the system LiMnVO4-Mn3(VO4)2

    International Nuclear Information System (INIS)

    The synthesis of orthorhombic Mn3(VO4)2 via a simple solid state route as well as the description of a new tetragonal high temperature phase are reported in this paper. Additionally, the system LiMnVO4-Mn3(VO4)2 (=Mn1.5VO4), described by the formula LixMn1.5-x/2VO4, is investigated in detail, showing that substitution of one Mn2+ in Mn1.5VO4 by two Li+ ions favors the formation of the tetragonal high temperature phase for x?0.22. This substitution is facilitated by the statistical half occupancy of the 4b site by Mn2+ in tetragonal Mn1.5VO4, whereas additional crystallographic sites would have to be occupied in the orthorhombic phase. The inverse substitution of Li by Mn in orthorhombic LiMnVO4 is also shown to be possible in the range 0.72?x?1. For 0.22?x?0.72, there is a large miscibility gap with a two phase mixture of the tetragonal Mn1.5VO4 type and orthorhombic LiMnVO4 type phases. - Graphical Abstract: The unusual coordination of Mn in the form of a stella quadrangula with the surrounding vanadate groups. Highlights: ? First synthesis of orthorhombic Mn3(VO4)2 via a simple solid state route. ? The crystal chemistry of the phases involved is rather complicated and it depends on the amount of Li that is incorporated. ? System LiMnVO4-Mn3(VO4)2 (=Mn1.5VO4), described by the formula LixMn1.5-x/2VO4, is investigated in detail.

  6. Selective Synthesis of Mesoporous and Nanorod CeVO4 without Template

    International Nuclear Information System (INIS)

    A simple and efficient method has been established for the selective synthesis of mesoporous and nanorod CeVO4 with different precursors by sonochemical method. CeVO4 nanorod can be simply synthesized by ultrasound irradiation of Ce(NO3)3 and NH4VO3 in aqueous solution without any surfactant or template. While mesoporous CeVO4 with high specific surface area can be prepared with Ce(NO3)3, V2O5 and NaOH in the same way. Mesoporous CeVO4 has a specific surface area of 122 m2 g-1 and an average pore size of 5.2 nm; CeVO4 nanorods have a diameter of about 5 nm, and a length of 100-150 nm. The ultrasound irradiation and ammonia in the reactive solution are two key factors in the formation of such rod-like products. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) and differential thermal analyses (DTA), UV/vis absorption spectroscopy and Brunauer-Emmett-Teller (BET) were applied for characterization of the as-prepared products

  7. Securing VoIP keeping your VoIP network safe

    CERN Document Server

    (Bud) Bates, Regis J Jr

    2015-01-01

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

  8. Graphene quantum dot sensitized leaf-like InVO4/BiVO4 nanostructure: a novel ternary heterostructured QD-RGO/InVO4/BiVO4 composite with enhanced visible-light photocatalytic activity.

    Science.gov (United States)

    Lin, Xue; Wang, Yushuang; Zheng, Jia; Liu, Chang; Yang, Yang; Che, Guangbo

    2015-11-28

    Leaf-like InVO4/BiVO4 nanostructures with sizes of 2-5 ?m were synthesized by a simple hydrothermal method. Graphene quantum dots (QD-RGO) were then deposited onto the surfaces of the leaf-like InVO4/BiVO4 crystals through a facile deposition-precipitation technique. Under visible light irradiation (? > 420 nm), the QD-RGO/InVO4/BiVO4 photocatalyst degraded rhodamine B (Rh B) efficiently and displayed a much higher photocatalytic activity than pure BiVO4, InVO4, RGO/InVO4, RGO/BiVO4 or an InVO4/BiVO4 hybrid. The InVO4/BiVO4 photocatalyst with 3 wt% of QD-RGO exhibited the highest photocatalytic efficiency. The quenching effects of different scavengers demonstrated that O2?(-) played a major role in Rh B degradation. It was elucidated that the excellent photocatalytic activity of QD-RGO/InVO4/BiVO4 for the degradation of Rh B under visible light (? > 420 nm) can be ascribed to the extended absorption in the visible light region resulting from the QD-RGO loading, the high specific surface area, and the efficient separation of photogenerated electrons and holes through the QD-RGO/InVO4/BiVO4 heterostructure. PMID:26486959

  9. Optical Properties of Thermochromic VO2 Nanoparticles

    Science.gov (United States)

    Laaksonen, Katri; Li, S.-Y.; Puisto, S. R.; Niklasson, G. A.; Ala-Nissilä, T.; Nieminen, R. M.

    Thermochromic VO2 undergoes metal-insulator transition at temperatures relatively near room temperature. The transition affects its optical properties especially at the near infrared (NIR) wavelengths. Consequently, thin films of VO2 have been proposed for energy-saving applications such as window coatings. At high temperatures, metal VO2 has high reflectivity of NIR light which is absorbed or transmitted at low temperatures. However, if used as nanoparticles instead of thin films, the optical properties of the high-temperature metal VO2 are significantly different. Metal nanoparticles show strong surface plasmon resonance absorption which for VO2 is at NIR wavelengths changing the high reflectivity of NIR light in thin films to absorption in nanoparticles.

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

    Directory of Open Access Journals (Sweden)

    Martha Angélica Gutiérrez-Aguirre

    2000-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Wendy Zumbado-Rivera

    2006-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Luciana Irene Gallardo

    2015-03-01

    Full Text Available La estimación de la biomasa en las poblaciones de insectos, es un factor clave para cuantificar los recursos disponibles y los flujos de energía en las redes tróficas de los ecosistemas. Cornops aquaticum es un herbívoro común en las plantas de Eichhornia en los humedales del nordeste de Argentina. Nuestro objetivo fue analizar la variación de su biomasa en relación a las distintas categorías de edades de la población de este acridio, en dos plantas huésped: Eichhornia azurea y Eichhornia crassipes. Para ello, se realizaron muestreos estándar de las poblaciones de C. aquaticum con una red entomológica de 70cm de diámetro, en dos humedales con E. azurea y E. crassipes en las provincias de Corrientes y Chaco; además, se obtuvo el peso seco de los individuos (de manera directa e indirecta y, se propuso un modelo de regresión para estimar la biomasa de C. aquaticum de manera indirecta a partir de una medida de dimensión lineal (longitud del fémur posterior. Un total de 2 307 individuos fueron recolectados y separados en distintas categorías de edades; se obtuvo su abundancia y distintas medidas de dimensión lineal. El modelo propuesto fue lnPS=lna+b*lnH (donde PS=peso seco, a y b son constantes y H=longitud del fémur posterior (R²=0.97. Las variaciones en la biomasa de las poblaciones de C. aquaticum se debieron a la abundancia relativa de cada categoría de edad y al peso seco individual de estos acridios. No hubo diferencias significativas entre la biomasa de las poblaciones de C. aquaticum obtenida por los métodos directo e indirecto en las praderas flotantes de E. azurea y E. crassipes. Este modelo facilita el cálculo de la biomasa individual y poblacional de C. aquaticum y acelera el procesamiento de un gran número de muestras. Finalmente, los valores altos de biomasa poblacional e individual de las categorías de edades (especialmente en adultos enfatizan la importancia de C. aquaticum como consumidor y como recurso para los depredadores en las redes alimenticias de las praderas flotantes de Eichhornia.

  13. Security in VoIP

    Directory of Open Access Journals (Sweden)

    Floriana GEREA

    2012-04-01

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

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

    Directory of Open Access Journals (Sweden)

    TALAL AL-KHAROBI

    2012-08-01

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

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

    OpenAIRE

    TALAL AL-KHAROBI; Mohmmed Abduallah Al-Mehdhar

    2012-01-01

    Voice over IP (VoIP), use of the packet switched internet for telephony, has improved substantially in the past few years. On the other hand, VoIP has many challenges that do not exist in the public switched telephone network (PSTN), a circuit switched system. VoIP is an application running on the internet, and therefore inherits the internet’s security issues. It is important to realise that VoIP is a relatively young technology, and with any new technology, security typically improves with ...

  16. Performance Evaluation for VoIP on Campus

    Directory of Open Access Journals (Sweden)

    Rendy Munadi

    2013-09-01

    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.  

  17. A Comprehensive Secure VoIP Solution

    OpenAIRE

    Ashraf D. Elbayoumy; Simon Shepherd

    2007-01-01

    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.

  18. LA BIOMASA MICROBIANA EN SUELOS DE MONTAÑA CON DIFERENTES USOS: UN ESTUDIO DE LABORATORIO

    Directory of Open Access Journals (Sweden)

    A. Cruz Ruiz

    2012-01-01

    Full Text Available El uso agrícola de los suelos del Parque Nacional Nevado de Toluca (PNTT, conlleva prácticas como la utilización creciente de agroquímicos. Para investigar el efecto de la aplicación de fertilizantes nitrogenados y biocidas de uso generalizado en la zona de estudio sobre la biomasa microbiana y la mineralización del carbono (C, se realizó una incubación de suelos del PNNT con diferentes usos: bosque (bajo la copa de oyamel (Abies religiosa, destinados al pastoreo (pradera y cultivado con maíz. Con los siguientes tratamientos: sulfato deamonio (585.36 kg ha-1, urea (250 kg ha-1, 2, 4-D (1 L ha-1, captan (2 kg ha-1 y suelos sin aplicación. La mineralización del C, el nitrógeno de la biomasa microbiana (NBM y el carbono de la biomasa microbiana (CBM se midieron a los 56 días de incubación. Los resultados mostraron que el cambio de uso de suelo de bosque a cultivo disminuye la biomasa microbiana, la proporción de CBM y NBM en los suelos de cultivo fue menor en más del 55% en comparación con los suelos de bosque. Los tratamientos 2, 4-D y captan dieron lugar al decremento significativo del CBM en los suelos de bosque, hasta en un 40 %, con respecto al suelo sin aplicación. La aplicación de captan favoreció el incremento del CBM en los suelos de pradera y cultivo. El NBM aumentó en los tres suelos con diferente uso al aplicar urea. La adición de sulfato de amonio, urea, 2, 4-D amina o captan causa efectos diferenciados en los suelos de bosque, pradera y cultivo indicando que el impacto de los biocidas y fertilizantes está relacionado con la degradación de los mismos.

  19. Scalable architecture for VoIP privacy

    Science.gov (United States)

    Medvinsky, Alexander

    2001-07-01

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

  20. PRODUCCIÓN DE BIOMASA DE Artemia franciscana Kellogg 1906 UTILIZANDO DIFERENTES DIETAS

    Directory of Open Access Journals (Sweden)

    Rosario Cisneros

    2009-01-01

    Full Text Available 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 del 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 %.

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

    Directory of Open Access Journals (Sweden)

    Floriberto Solis-Mendoza

    2012-01-01

    Full Text Available Se estudió el efecto del suelo contaminado con plomo en el híbrido experimental de calabacita (Cucurbita pepo L. denominado 'Termo'. Se cultivó calabacita en bolsas negras de polietileno, a cielo abierto. Se evaluaron las variables distribución de la producción de biomasa, altura de planta, contenido de clorofila y acumulación de plomo en raíz, tallo, hoja, flor y fruto. Los tratamientos fueron 0, 65, 300 y 1000 ppm de plomo aplicado al suelo a través de Pb(NO32. Se utilizó un diseño experimental de bloques completos al azar con seis repeticiones, y la unidad experimental fue una bolsa negra de polietileno con dos plantas. Las evaluaciones se hicieron 50 días después del trasplante para altura de planta y contenido de clorofila, y a los 52 días para peso fresco, peso seco y acumulación de plomo. Se observó que la altura de planta fue significativamente menor cuando se aplicó plomo a cualquier dosis. También se observó que la mayor acumulación de biomasa en raíz y tallo fue producida con la dosis 300 ppm y en fruto con 65 ppm de plomo, en tanto que la biomasa total y las unidades SPAD (clorofila no resultaron afectadas. De las estructuras comestibles, la flor presentó una mayor acumulación del metal que el fruto. A bajas dosis de plomo, la flor fue la estructura que más lo acumuló. Esto sugiere que es conveniente evaluar el contenido de metales pesados en productos agrícolas para consumo humano, aun cuando provengan de suelos contaminados sin intención.

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

    KAUST Repository

    Schuster, Cosima B.

    2013-08-01

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

  3. Electron paramagnetic resonance and optical absorption study of VO2+-doped sodium zinc sulfate tetrahydrate single crystals

    International Nuclear Information System (INIS)

    Single-crystal electron paramagnetic resonance (EPR) studies of VO2+ doped in sodium zinc sulfate tetrahydrate (Na2Zn(SO4)2·4H2O) have been carried out at room temperature. The results show the presence of three magnetically inequivalent VO2+ sites with different populations. The VO2+ impurity ions take up substitutional positions in the host lattice replacing Zn2+ ions. The angular variation of EPR spectra in three mutually orthogonal planes, bc, a*c and ba*, are used to determine the spin-Hamiltonian parameters. The optical absorption spectrum of VO2+ ions doped in the crystal lattice is also recorded at room temperature in the wavelength range 325-1100 nm. This is utilized to study the energy level structure of the VO2+ ion. By correlating the EPR and optical data, various molecular orbital coefficients of the VO2+ ion with its ligands are evaluated and the nature of bonding in the crystal is discussed.

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

    Scientific Electronic Library Online (English)

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

    2012-12-01

    Full Text Available 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.

  5. The Vanadium(V) Oxoazides [VO(N3)3], [(bipy)VO(N3)3], and [VO(N3)5](2-).

    Science.gov (United States)

    Haiges, Ralf; Vasiliu, Monica; Dixon, David A; Christe, Karl O

    2015-07-27

    Vanadium(V) oxoazide [VO(N3)3] was prepared through a fluoride-azide exchange reaction between [VOF3] and Me3SiN3 in acetonitrile solution. When the highly impact- and friction-sensitive compound [VO(N3)3] was reacted with 2,2?-bipyridine, the adduct [(bipy)VO(N3)3] was isolated. The reaction of [VO(N3)3] with [PPh4]N3 resulted in the formation and isolation of the salt [PPh4]2[VO(N3)5]. The adduct [(bipy)VO(N3)3] and the salt [PPh4]23[VO(N3)5] were characterized by vibrational spectroscopy and single-crystal X-ray structure determination, making these compounds the first structurally characterized vanadium(V) azides. PMID:26072899

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

    Scientific Electronic Library Online (English)

    Marcos David, Silva-Cavalcante; Renata Gonçalves, Silva; Rodrigo Poles, Urso; Rogério Carvalho, Silva; Carlos Rafaell, Correia-Oliveira; Victor Gustavo Ferreira, Santos; Adriano Eduardo, Lima-Silva; Rômulo, Bertuzzi.

    2013-06-01

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

  7. Understanding VoIP from Backbone Measurements

    OpenAIRE

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

    2007-01-01

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

  8. A low cost preparation of VO2 thin films with improved thermochromic properties from a solution-based process

    International Nuclear Information System (INIS)

    This paper describes a solution-based route to synthesize vanadium dioxide (VO2) thermochromic thin films on glass substrate by spin-coating technology followed by nitrogen-annealing with vanadium pentoxide (V2O5) and oxalic acid (H2C2O4) as source material, which is fairly economical and practical. Surface morphologies indicate that the films obtained by this method are homogeneous and particulate, irregular prisms emerge as the annealing temperatures increase. X-ray diffractions show that films annealed at relatively low temperature are pure monoclinic phase with a preferred orientation of (011). NaV4O7 and NaV6O15 form along with raising the heating temperatures. VO2 films obtained exhibit excellent visible transparency and switching property at near-infrared wavelengths across the metal–semiconductor transition. Transmittance change at ? = 2000 nm of VO2 thin film annealed at 450 °C attains as high as 41.5% and its solar modulation efficiency reaches up to 8.8%. The W-doped VO2 film at a doping level of 1 at.% exhibits a thermochromic switch at 37 °C with a narrow hysteresis, which will greatly favor the practical application of VO2-based smart windows. - Highlights: ? Vanadium dioxide thermochromic film was prepared via a solution-based deposition. ? Tungsten doping reduced the phase transition temperature to 37 °C. ? Tungsten doping narrowed the transmittance hysteresis loop. ? Our results will propel the application to vanadium dioxide-based smart windows

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

    Science.gov (United States)

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

    2015-06-01

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

  10. Visible light driven photocatalysis and antibacterial activity of AgVO3 and Ag/AgVO3 nanowires

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Ag/AgVO3 and pure AgVO3 nanowires synthesized by sonochemical process. • Characterization done using XRD, SEM, TEM, EDX and BET analysis. • Visible light degradation of RhB by Ag/AgVO3 within 45 min. • Antibacterial activity of Ag/AgVO3 demonstrated. - Abstract: Ag/AgVO3 nanowires and AgVO3 nanorods were synthesized in aqueous media via a facile sonochemical route. The as-synthesized products were characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area analysis, scanning electron microscopy together with an energy dispersion X-ray spectrum analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results revealed that inert atmosphere promotes the formation of Ag/AgVO3 nanowires. The photocatalytic studies revealed that the Ag/AgVO3 nanowires exhibited complete photocatalytic degradation of Rhodamine B within 45 min under visible light irradiation. The antibacterial activity of Ag/AgVO3 nanowires was tested against Escherechia coli and Bacillus subtilis. The minimum growth inhibitory concentration value was found to be 50 and 10 folds lower than for the antibiotic ciprofloxacin for E. coli and B. subtilis, respectively. The antibacterial properties of the ?-AgVO3 nanorods prove that in case of the Ag dispersed Ag/AgVO3 nanowires, the enhanced antibacterial action is also due to contribution from the AgVO3 support

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Berlanga-Labari, C.

    2008-08-01

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

    La combustión de biomasa, especialmente de paja de cereal, genera un ambiente muy corrosivo, particularmente, cerca de los tubos sobrecalentadores. El cloro es el principal agente corrosivo en las plantas de biomasa. Este trabajo se centra en comprobar el comportamiento de ocho aleaciones comerciales en una ambiente de combustión de biomasa. Los materiales estudiados han sido las siguientes: AISI 347 CG (1.4550, AISI 347 FG (1.4550, AISI 316LN (1.4910, ESSHETE 1250 (1.4982, AC 66 (1.4877, X20CrMoV12:1 (1.4922 y AISI 347 recubiertos con Inconel 625 e Inconel 686. Los ensayos se han realizado en la caldera de la planta de biomasa de Sangüesa (Navarra, España durante 8.000 y 15.000 h a una temperatura de 500-550 °C. Los resultados indican un buen comportamiento de los aceros inoxidables austeníticos y de las aleaciones de Inconel, mientras que el del acero martensítico no ha sido aceptable. Se ha propuesto el mecanismo conocido como “oxidación activa” para interpretar el comportamiento a la corrosión de estos materiales en estos medios.

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

    Scientific Electronic Library Online (English)

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

    2011-09-01

    Full Text Available 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

  14. Transformación de biomasa en biocombustibles de segunda generación / From biomass to second generation biofuels

    Scientific Electronic Library Online (English)

    Laura, Faba; Eva, Díaz; Salvador, Ordóñez.

    2014-11-01

    Full Text Available El agotamiento de las materias primas no renovables, así como la creciente conciencia ambiental ha motivado la valorización de la biomasa para la producción de energía. Aunque los primeros esfuerzos se centraron en el desarrollo de los biocombustibles de primera generación -según la materia prima co [...] n que se producen-, la tendencia actual es hacia la investigación en los biocombustibles de segunda generación, que permiten la transformación de la biomasa lignocelulósica (obtenida a partir de residuos forestales o de cultivos, maderas de bajo precio o serrín) en energía. La transformación de la madera en biocombustibles puede llevarse a cabo por vías biológicas o químicas. Entre las rutas químicas, hay tres posibilidades principales: gasificación, pirólisis o hidrólisis. Este trabajo tiene como objetivo hacer una revisión de las posibilidades para obtener biocombustibles de segunda generación mediante procesos químicos hidrolíticos, que implica varios pasos: pretratamiento de la biomasa (que puede ser físico o químico), hidrólisis de la biomasa, deshidratación de los azúcares, condensación aldólica e hidrogenación/deshidratación completa para obtener los alcanos lineales (biodiesel). Abstract in english The depletion of the non-renewable raw materials as petroleum, coal or natural gas as well as the increasing environmental conscience has motivated the valorization of biomass for energy production. Although the first efforts were focused on the development of the first generation biofuels -accordin [...] g to the raw material-, nowadays the research is focused on the second generation biofuels, which allows the transformation of lignocellulosic biomass (from forest or crops wastes, low-priced woods or sawdust) into energy. The transformation of wood into biofuels can be carried out by biological or chemical means. Among the chemical routes, there are three main possibilities: gasification, pyrolisis or hydrolysis. This paper aims to review the technological advances to obtain biofuels by the third route, since it allows using the most abundant forms of biomass, cellulose and hemicelluloses. This chemical process involves several steps: pretreatment of the biomass (by physical or chemical route), hydrolysis of the biomass, dehydration of sugars, aldolization and hydrogenation/dehydration until n-alcanes (biofuels) are achieved.

  15. Similar foliage area but contrasting foliage biomass between young beech and spruce stands / Porovnate?ná plocha avšak kontrastná biomasa asimila?ných orgánov medzi mladými porastmi buka a smreka

    Directory of Open Access Journals (Sweden)

    Konôpka Bohdan

    2014-12-01

    Full Text Available Výskum sa zameral na mladé porasty buka lesného (Fagus sylvatica a smreka oby?ajného (Picea abies rovnakého veku (12 rokov, ve?mi podobných dimenzií stromov, rastúcich na totožnom stanovišti. Na základe odberu vzorníkov celých stromov (všetky ?asti okrem jemných kore?ov sme skonštruovali alometrické vz?ahy pre stromové komponenty. Ako nezávislá premenná sa použila hrúbka na báze kme?a (d0. Modely vyjadrili nielen biomasu konárov, kme?a, hrubých kore?ov a asimila?ných orgánov, ale aj plochu asimila?ných orgánov a špecifickú listovú plochu (specific leaf area; SLA. Zistili sme, že základné morfologické vlastnosti asimila?ných orgánov varírovali pri obidvoch drevinách pozd?ž vertikálneho profilu koruny. V prípade smreka sa zistili odlišné hodnoty plochy ihlíc a SLA medzi jednotlivými ro?níkmi ihlíc. Na úrovni stromu mali buky ove?a viac biomasy drevných ?astí ako smreky, opa?ná situácia bola pri asimila?ných orgánoch. Preto hodnoty podielu medzi biomasou asimila?ných orgánov a celkovou biomasou stromu, ako aj pomeru medzi plochou asimila?ných orgánov a celkovou biomasou stromu boli výrazne vyššie pri smreku než buku. Na úrovni porastu mala smre?ina vyššie hodnoty indexu listovej plochy, t. j. LAI (18,64 m2.m?2 v porovnaní s bu?inou (12,77 m2.m?2. Kým biomasa asimila?ných orgánov bola 4,6-krát vä?šia v smrekovom než v bukovom poraste, biomasa drevných ?asti bola porovnate?ná v obidvoch porastoch. Tieto kontrasty nazna?ujú výrazne odlišnú rastovú stratégiu, resp. alokáciu biomasy medzi bu?inami a smre?inami v mladých štádiách

  16. Service Improvements for a VoIP Provider

    OpenAIRE

    LI, ZHANG

    2009-01-01

    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...

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

    CERN Document Server

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

    2015-01-01

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

  18. Formation and photodepletion of cluster ion-messenger atom complexes in a cold ion trap: Infrared spectroscopy of VO+, VO2+, and VO3+

    Science.gov (United States)

    Brümmer, Mathias; Kaposta, Cristina; Santambrogio, Gabriele; Asmis, Knut R.

    2003-12-01

    A novel experimental technique is described in which radiation from a free electron laser is used to measure infrared spectra of gas-phase cluster ions via vibrational predissociation of the corresponding ion-messenger atom complexes. The weakly bound complexes are formed in a temperature-controllable, radio frequency ion trap. This technique is applied to the study of the vibrational spectroscopy of the monovanadium oxide cluster cations VO+, VO2+, and VO3+.

  19. Formation and photodepletion of cluster ion-messenger atom complexes in a cold ion trap: Infrared spectroscopy of VO+, VO2+, and VO3+

    International Nuclear Information System (INIS)

    A novel experimental technique is described in which radiation from a free electron laser is used to measure infrared spectra of gas-phase cluster ions via vibrational predissociation of the corresponding ion-messenger atom complexes. The weakly bound complexes are formed in a temperature-controllable, radio frequency ion trap. This technique is applied to the study of the vibrational spectroscopy of the monovanadium oxide cluster cations VO+, VO2+, and VO3+

  20. Biomassa de rotíferos em ambientes dulcícolas: Revisão de métodos e fatores influentes / Rotifer biomass in freshwater environments: Review of methods and influencing factors / Biomasa de rotíferos en ambientes dulciacuícolas: Revisión de métodos y factores influyentes

    Scientific Electronic Library Online (English)

    Dayane, Christian Rossa; Claudia, Costa Bonecker; Leandro, Junio Fulone.

    2007-04-01

    Full Text Available A biomassa de uma comunidade aquática fornece informações quantitativas da matéria orgânica disponível nos diferentes níveis tróficos. As dificuldades metodológicas para se estimar a biomassa zooplanctônica explicam os poucos estudos existentes, principalmente no Brasil. Neste estudo objetiva-se des [...] crever as metodologias mais utilizadas na estimativa da biomassa de rotíferos, analisar suas vantagems e desvantagems, comparar resultados obtidos com cada técnica, e investigar alguns fatores que influenciam sua biomassa. A estimativa mais utilizada é a determinação do volume, a partir de dimensões lineares. Estudos apontam que os valores estimados da biomassa de rotíferos podem variar de acordo com as metodologias de amostragem, preservação dos indivíduos, características limnológicas dos ambientes e genotípicas dos indivíduos, predação, disponibilidade de alimento, além da sazonalidade. Todos esses fatores evidenciam a necessidade de se estimar a biomassa ao invés da utilização de equações já descritas na literatura, bem como a importância de se descrever detalhadamente a metodologia utilizada em cada amostragem, e algumas características limnológicas dos ambientes estudados. Abstract in spanish La biomasa de una comunidad acuática provee información cuantitativa de la materia orgánica disponible en los diferentes niveles tróficos. Las dificultades metodologías en la estimación de la biomasa zooplanctónica explican los pocos estudios existentes, principalmente en Brasil. Se describen los mé [...] todos más utilizados en la estimación de la biomasa de rotíferos, se analizan sus ventajas y desventajas, se comparan los resultados obtenidos con cada técnica, y se discuten algunos factores que influyen en su biomasa. El método más utilizado es la determinación del biovolumen, obtenido a partir de las dimensiones lineales de los rotíferos. La mayor parte de los estudios sugieren que la biomasa de rotíferos varía de acuerdo con los métodos de muestreo, la conservación de los individuos, la depredación y la disponibilidad de alimentos, además de la estacionalidad. Todos estos factores evidencian la necesidad de estimar la biomasa en lugar de utilizar ecuaciones ya descritas en la literatura, así como la importancia de describir el método utilizado en cada muestreo y algunas características limnológicas de los ambientes estudiados. Abstract in english The biomass of an aquatic community provides quantitative information from available organic matter in different trophic levels. The methodological difficulties in estimating zooplankton biomass explain the scarcity of existing studies, particularly in Brazil. The most used methodologies for rotifer [...] biomass estimation are described and their advantages and disadvantages analyzed. Results obtained with the different techniques are compared and some factors influencing the biomass are discussed. The most commonly used methodology is the biovolume, calculated from rotifer linear dimensions. Studies point out that rotifers biomass vary according to sampling methodologies, individual preservation, environments limnological characteristics, individual genotypical characteristics, predation, food resource availability and seasonality. All these factors emphasize the importance of estimating biomass instead of using equations already described in the literature, as well as the importance to describe in detail the methodology employed in each sampling and some limnological features of the studied environments.

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

    Scientific Electronic Library Online (English)

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

    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. 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.

  2. El cultivo y el agua de riego sobre el carbono de la biomasa microbiana

    Scientific Electronic Library Online (English)

    Magaly, Ruiz; Jorge, Paolini.

    2004-04-01

    Full Text Available En este estudio se determinó el carbono de la biomasa microbiana en ocho suelos cultivados con caña de azúcar y banano, regados con aguas de distinto origen (residuales, de pozo, de lago), y en dos suelos bajo vegetación natural (suelos testigo), localizados todos en la Cuenca del Lago de Valencia. [...] El carbono de la biomasa microbiana (C-BM) se determinó por el método de la respiración inducida por sustrato. Los valores obtenidos variaron entre 206 y 1.553 µg C-BM g-1 suelo, siendo más altos en los suelos testigos y en los suelos lacustrinos sembrados con caña de azúcar bajo riego con aguas residuales industriales y domésticas. Los valores del C-BM resultaron superiores en los suelos bajo banano (P Abstract in english In the present study, soil microbial biomass carbon (MBC) was determined in eight soils located in the Valencia Lake basin, cultivated with sugarcane or banana and irrigated with waters of different composition or origin (waste-, ground- and lake-water), and in two soils under natural vegetation (co [...] ntrol soils). MBC was estimated by substrate induced respiration method. MBC varied between 206 and 1.553 µg microbial C g-1 soil. Highest values occurred in control soils and in the lacustrine soil cultivated with sugar cane and irrigated with waste waters. The values of MBC were higher in the alluvial soils cultivated with sugarcane than in the alluvial soils cultivated with banana (P

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

    Directory of Open Access Journals (Sweden)

    J. Garduño-González

    2009-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Jorge M Mendoza

    2012-01-01

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

  5. REMOCIÓN DE PLOMO Y NÍQUEL EN SOLUCIONES ACUOSAS USANDO BIOMASAS LIGNOCELULÓSICAS: UNA REVISIÓN

    Directory of Open Access Journals (Sweden)

    Edgar Quiñones

    2013-12-01

    Full Text Available En la presente revisión, se identifican los bioadsorbentes extraídos de biomasas residuales utilizadas en la remoción de dos metales pesados, que presenta una amplia toxicidad para el ambiente: plomo y níquel. Se evalúa la capacidad de remoción de los mismos, destacando aquellos en los que se han obtenido altos porcentajes de remoción, mostrando la cinética aplicada en estos experimentos. Se encontró, que los bioadsorbentes más usados incluyen residuos de madera, cáscaras de frutos secos, residuos de cereales y cítricos. Para la remoción de plomo (II, el bagazo de caña de azúcar, con una capacidad de remoción de 333mg/g y para el níquel (II, la corteza de Acacia, con una capacidad de remoción de 294,1mg/g, han sido los bioadsorbentes con mayor eficiencia de remoción. Se encuentra que, en la mayoría de los experimentos, la cinética del proceso de adsorción es regida por la ecuación cinética de pseudo-segundo orden. Se recomienda el diseño de plantas piloto para la remoción de iones metálicos con las biomasas que mostraron mayor capacidad de adsorción, con el fin de que estos procesos puedan ser llevados a escala industrial.

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

    OpenAIRE

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

    2005-01-01

    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 ...

  7. Modular VO oriented Java EE service deployer

    Science.gov (United States)

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

    2014-07-01

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

  8. Vplyv pesticídov na spolo?enstvo aktinomycét vo vysokohorskej pôde.

    Czech Academy of Sciences Publication Activity Database

    Selešiová, Z.; Javoreková, S.; Krišt?fek, Václav; Chro?áková, Alica

    Bratislava : Vydavate?stvo Univerzity Komenského, 2010, s. 120-127. ISBN 978-80-223-2796-1. [Život v pôde /11./. Bratislava (SK), 26.01.2010-27.01.2010] R&D Projects: GA MŠk LC06066 Grant ostatní: SAV(SK) 1/0404/09; SAV(SK) 3/6228/08 Institutional research plan: CEZ:AV0Z60660521 Keywords : pesticides * actinomycetes * grassland Subject RIV: EH - Ecology, Behaviour

  9. Jestonija vo vneshnej politike Rossijskoj Federacii: prognoz na srednesrochnuju perspektivu

    Directory of Open Access Journals (Sweden)

    Lanko D. A.

    2014-02-01

    Full Text Available This article shows why the non-existent political dialogue between Russia and Estonia will hardly develop in the next five years and why Estonia can lose its significance for the Russian foreign policy rhetoric and Russian mass media. This conclusion is drawn from a medium-term forecast about the changing role of Estonia in Russian foreign policy. The forecast is based on the scenario methodology, which suggests that the modern means of political forecasting make it possible to make conclusions not about the future states of political phenomena, but rather about the trends of current states, which are called scenarios. The article describes the four possible scenarios of changes in the role of Estonia in Russian foreign policy that are evaluated from the perspective of the development of Russian-Estonian relations and factors affecting the probability of each scenario. It is shown that any change in the role of Estonia in Russian foreign policy depends not only on the specific actions of the Estonian elite, for example their readiness to change their position on the participation of Russian-speaking population in the democratic decision-making process or the evaluation of controversial events of the past, but also on the meaning that will be attached to these actions by the Russian elite.

  10. Steganography of VoIP streams

    CERN Document Server

    Mazurczyk, Wojciech

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2006-12-01

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

  12. Secure Session Mobility for VoIP

    OpenAIRE

    Dzaferagic, Samir

    2008-01-01

    High data rate wireless packet data networks have made real-time IP based services available through mobile devices. At the same time, differences in the characteristics of radio technologies (802.11/WiFi and 3G networks) make seamless handoff across heterogeneous wireless networks difficult. Despite this, many believe that the ultimate goal of next generation networks (often referred to as the fourth generation) is to allow convergence of such dissimilar heterogeneous networks. Supporting vo...

  13. What are suspicious VoIP delays?

    CERN Document Server

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    2010-01-01

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

  14. Cloudspace: virtual environments in the VO

    Science.gov (United States)

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

    2008-08-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-01-15

    In this paper, a simple, safe and cost-saving precipitation-peptization method was proposed to prepare VO2 sol by using inorganic VOSO4-NH3?H2O-H2O2 reactants system in air under room temperature. In this process, VOSO4 was firstly precipitated to form VO(OH)2, then monometallic species of VO(O2)(OH)(-) were formed through the coordination between VO(OH)2 and H2O2. The rearrangement of VO(O2)(OH)(-) in a nonplanar pattern and intermolecular condensation reactions result in multinuclear species. Finally, VO2 sol is prepared through the condensation reactions between the multinuclear species. After drying the obtained sol at 40°C, VO2 xerogel exhibiting monoclinic crystal structure with the space group of C2/m was prepared. The crystal structure of VO2 nanoparticles was transferred to monoclinic crystal structure with the space group of P21/c (VO2(M)) by annealing the xerogel at 550°C. Both XRD and TEM analysis indicated that the nanoparticles possess good crystallinity with crystallite size of 34.5nm as estimated by Scherrer's method. These results suggest that the VO2 sol has been prepared successfully through the proposed simple method. PMID:26433476

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

    Scientific Electronic Library Online (English)

    María del Rosario, Iglesias; Alicia Haydée, Barchuk.

    2010-04-01

    Full Text Available 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).

  18. Proceso de gasificación de biomasa: una revisión de estudios teórico- experimentales / Biomass gasification process: theoretical and experimental studies a review

    Scientific Electronic Library Online (English)

    Juan, Pérez; David, Borge; John, Agudelo.

    2010-03-01

    Full Text Available La situación energética y medioambiental mundial hace que la generación de energía mediante sistemas basados en energías renovables tome cada vez una mayor relevancia. Estos sistemas tienen una doble ventaja ya que posibilitan la diversificación energética y reducen la dependencia del petróleo a la [...] vez que se disminuyen las emisiones globales de CO2. La biomasa es uno de los recursos energéticos con mayor potencial tanto en países desarrollados como emergentes pero sigue sin sufrir el desarrollo esperado. La gasificación de biomasa es uno de los sistemas con gran potencial ya que permite la generación tanto de energía térmica como eléctrica, mediante tecnologías de bajo costo como los gasificadores de lecho fijo (potencias medias- bajas), o reactores de lecho fluidizado con tecnología más exigente y con mayor capacidad de generación. La transformación de la biomasa en un combustible gaseoso, aprovechable en motores de combustión interna alternativos o en turbinas de gas como combustible, exige que la biomasa atraviese varios procesos termoquímicos, compuestos por reacciones endotérmicas (secado, devolatilización y reducción) y exotérmicas (oxidación de volátiles y carbón). La selección de un gasificador requiere conocer las propiedades de la biomasa, mientras que el diseño del mismo exige conocer el fenómeno termoquímico por completo. El objetivo de este trabajo es presentar una revisión actualizada de los diferentes planteamientos tanto teóricos como experimentales desarrollados para estudiar el proceso de gasificación de biomasa, tanto en lecho fijo como en lecho fluidizado, con miras a diseñar gasificadores de biomasa. Abstract in english Each day the energy systems relying on renewable resources are more relevant in the world energy politics due to the fossil energy and environmental crisis. These systems increase energy resources of countries, reduce the oil dependency, and diminish CO2 global emissions. Biomass is one of the renew [...] able resources with higher potential in developing and developed countries. Biomass gasification has huge possibilities to be developed. Such as fixed bed gasifiers, or fluidized bed reactors with more technology demanding and more power capacity. Biomass transformation in a gaseous fuel to be used in a reciprocating internal combustion engine or gas turbines requires that biomass passes through several thermochemical stages. Endothermic reactions (drying, pyrolysis and reduction) and exothermic process (volatiles and carbon oxidation). To select a specific gasifier it is necessary to know biomass properties (chemical and physical), whereas to design a reactor it is necessary to know and understand the complete phenomena. The aim of this work is to show an actualized review about different theoretical and experimental approaches to study biomass gaification process in fixed and fluidized bed reactors in order to design biomass gasifiers.

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

    Directory of Open Access Journals (Sweden)

    Ismael Acosta

    2007-01-01

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

  20. 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)

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

    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 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

  1. VoIP Networks Monitoring and Intrusion Detection

    OpenAIRE

    Nassar, Mohamed

    2009-01-01

    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...

  2. Deployment of VoIP Technology: QoS Concerns

    OpenAIRE

    Lazzez, Amor; Slimani, Thabet

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Rosales Loaiza Nestor Luis

    2007-07-01

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

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

    Directory of Open Access Journals (Sweden)

    TATIANA RODRIGUEZ CHAPARRO

    2010-01-01

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

  5. Evidence of field-induced nucleation switching in opal: VO2 composites and VO2 films

    Science.gov (United States)

    Pevtsov, A. B.; Medvedev, A. V.; Kurdyukov, D. A.; Il'Inskaya, N. D.; Golubev, V. G.; Karpov, V. G.

    2012-01-01

    We show that electrical switching in opal-VO2 composites is governed by the electric field rather than voltage or current. This makes it similar to switching in chalcogenide glasses with the underlying mechanism identified as the field induced nucleation. However, the observed bias dependence of switching delay time is found to be noticeably different from that of standard VO2 films on “smooth” substrates. This difference is attributed to the disorder effects in polycrystalline structures. The model of field induced nucleation is shown to apply when properly modified to account for that disorder.

  6. Audio Codecs in VoIPv6: A Performance Analysis

    OpenAIRE

    Monjur Ahmed; Mohammad Sarwar Hossain Mollah

    2014-01-01

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

  7. The Astrophysical Virtual Observatory to EURO-VO Transition

    CERN Document Server

    Padovani, P

    2005-01-01

    The Astrophysical Virtual Observatory (AVO) initiative, jointly funded by the European Commission and six European organisations, had the task of creating the foundations of a regional scale infrastructure by conducting a research and demonstration programme on the VO scientific requirements and necessary technologies. The AVO project is now formally concluded. I highlight AVO's main achievements and then describe its successor, the EURO-VO project. With its three new interlinked structures, the Data Centre Alliance, the Facility Centre, and the Technology Centre, the EURO-VO is the logical next step for the deployment of an operational VO in Europe.

  8. Reservorios de biomasa aérea y de carbono en los manglares del golfo de Urabá (Caribe colombiano

    Directory of Open Access Journals (Sweden)

    Juan F Blanco-Libreros

    2015-12-01

    Full Text Available Los manglares son los principales reservorios de biomasa aérea (BA y carbono (C sobre el suelo entre los ecosistemas marino-costeros tropicales. A partir de datos estructurales de campo y de ecuaciones alométricas publicadas, se estiman los reservorios de BA y C en la vegetación de las cuatro áreas de manglar más extensas del golfo de Urabá. Los manglares del delta del río Atrato mostraron los mayores reservorios de BA y C (165 y 83 t/ha, respectivamente concentrados en árboles de Rhizophora mangle, al igual que los de la ensenada de Rionegro (115 y 58 t/ha, respectivamente. En el costado suroriental del Golfo, los mayores valores se obtuvieron en los manglares de Puerto César-Punta Coquito (85 y 43 t/ha, respectivamente, y por último los de Turbo (76 y 38 t C/ha, respectivamente, ambos dominados por Avicennia germinans. En Turbo predominaron árboles de R. mangle y Laguncularia racemosa de diámetros < 5 cm, reflejo de la fuerte intervención antrópica y los reservorios de BA y C son menores que los de Puerto César-Punta Coquito, más alejado de la cabecera urbana. Los reservorios de biomasa de los manglares del Golfo se encuentran dentro del rango observado en todo el mundo, pero los del delta del río Atrato se acercan más al límite superior registrado. Los manglares mejor conservados del golfo de Urabá son reservorios importantes de C en la BA. La magnitud del reservorio está inversamente relacionada con la distancia a los dos principales centros poblados.

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

    Directory of Open Access Journals (Sweden)

    Duque Escobar Santiago R.

    2000-06-01

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

  10. Nanometer scale electronic reconstruction at the interface between LaVO3 and LaVO4

    OpenAIRE

    Kourkoutis, L. Fitting; Hotta, Y.; Susaki, T.; Hwang, H. Y.; Muller, D. A.

    2007-01-01

    Electrons at interfaces, driven to minimize their free energy, are distributed differently than in bulk. This can be dramatic at interfaces involving heterovalent compounds. Here we profile an abrupt interface between V 3d2 LaVO3 and V 3d0 LaVO4 using electron energy loss spectroscopy. Although no bulk phase of LaVOx with a V 3d1 configuration exists, we find a nanometer-wide region of V 3d1 at the LaVO3/LaVO4 interface, rather than a mixture of V 3d0 and V 3d2. The two-dime...

  11. 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)

    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

    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 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

  12. 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

  13. Phase-Dependent Enhancement of the Green-Emitting Upconversion Fluorescence in LaVO4:Yb(3+), Er(3+).

    Science.gov (United States)

    Zhang, Feng; Li, Guoqiang; Zhang, Weifeng; Yan, Yu Li

    2015-08-01

    The phase-dependent upconversion luminescence properties of LaVO4:Er(3+) were studied to provide new insights into the design of new upconversion materials with high efficiency. Er(3+)-, Yb(3+)/Er(3+)-doped t-LaVO4 microcrystals were successfully synthesized by the disodium ethylenediaminetetraacetic acid (Na2EDTA)-assisted hydrothermal method. X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, luminescence spectroscopy, and thermogravimetric analysis (TGA) were used to characterize the samples. The results indicated that t-LaVO4 presents sheaf-like morphology, and the possible formation mechanism for these sheaves was proposed on the basis of time-dependent experiments. Furthermore, the phase-dependence (i.e., monoclinic- and tetragonal-type) upconversion luminescence properties were systematically studied, and the upconversion mechanisms were proposed according to spectral, pump power, and the concentration of Yb(3+) dependence analyses. It is worthwhile pointing out that the Er(3+)-doped t-LaVO4 exhibits a brighter green emission, which is approximately 10 times that of m-LaVO4:Er(3+) using a continuous 980 nm laser diode as the excitation source. This remarkable improvement was rationally analyzed on the basis of the composition, crystal structures, Raman spectra, morphology, and size. The comparative experiments suggest that the local structure of Er(3+) was considered as an important reason for the higher fluorescence intensity of t-LaVO4:Er(3+), which was also confirmed by the results of density functional theory (DFT) calculations. PMID:26203901

  14. Synthesis of a new vanadyl(IV) complex with trehalose (TreVO): insulin-mimetic activities in osteoblast-like cells in culture.

    Science.gov (United States)

    Barrio, Daniel A; Williams, Patricia A M; Cortizo, Ana M; Etcheverry, Susana B

    2003-04-01

    Vanadium compounds show interesting biological and pharmacological properties. Some of them display insulin-mimetic effects and others produce anti-tumor actions. The bioactivity of vanadium is present in inorganic species like the vanadyl(IV) cation or vanadate(V) anion. Nevertheless, the development of new vanadium derivatives with organic ligands which improve the beneficial actions and decrease the toxic effects is of great interest. On the other hand, the mechanisms involved in vanadium bioactivity are still poorly understood. A new vanadium complex of the vanadyl(IV) cation with the disaccharide trehalose (TreVO), Na(6)[VO(Tre)(2)].4H(2)O, here reported, shows interesting insulin-mimetic properties in two osteoblast cell lines, a normal one (MC3T3E1) and a tumoral one (UMR106). The complex affected the proliferation of both cell lines in a different manner. On tumoral cells, TreVO caused a weak stimulation of growth at 5 microM but it inhibited cell proliferation in a dose-response manner between 50 and 100 microM. TreVO significantly inhibited UMR106 differentiation (15-25% of basal) in the range 5-100 microM. On normal osteoblasts, TreVO behaved as a mitogen at 5-25 microM. Different inhibitors of the MAPK pathway blocked this effect. At higher concentrations (75-100 microM), the complex was a weak inhibitor of the MC3T3E1 proliferation. Besides, TreVO enhanced glucose consumption by a mechanism independent of the PI3-kinase activation. In both cell lines, TreVO stimulated the ERK phosphorylation in a dose- and time-dependent manner. Different inhibitors (PD98059, wortmannin, vitamins C and E) partially decreased this effect, which was totally inhibited by their combination. These results suggest that TreVO could be a potential candidate for therapeutic treatments. PMID:12761667

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

    Directory of Open Access Journals (Sweden)

    Ronaldo Nascimento Maciel

    2011-07-01

    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.

  16. Evolution of the spectral weight in the Mott-Hubbard series SrVO3-CaVO3-LaVO3-YVO3

    International Nuclear Information System (INIS)

    The Mott-Hubbard series SrVO3-CaVO3-LaVO3-YVO3 present a distinct metal-insulator transition. The microscopic origin of this transition can be related to the correlation effects in the electronic structure. The valence band photoemission results show very interesting trends across these Mott-Hubbard series. These results suggest that the O 2p states play an important role in the Mott-Hubbard transition. Some of the changes in the spectra are unexpected and cannot be explained by the current Mott-Hubbard theories (author)

  17. VO-compliant workflows and science gateways

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

    Wade, Phil; Wakelam, Mathew

    2008-05-01

    Phil Wade, sales and marketing director, and Mathew Wakelam, VoIP product manager, at alarm and communication specialist Static Systems Group, discuss wireless VoLP's potential in healthcare establishments and examine how, in particular, the technology can be successfully integrated with nurse call systems. PMID:18552104

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

    Scientific Electronic Library Online (English)

    Paulo Roberto, Santos-Silva; Alfredo José, Fonseca; Anita Weigand de, Castro; Júlia Maria D' Andréa, Greve; Arnaldo José, Hernandez.

    Full Text Available OBJETIVO: Determinar o grau de reprodutibilidade do consumo máximo de oxigênio (VO2max) em jogadores de futebol utilizando o protocolo de Heck modificado. MÉTODOS: Foram avaliados por duas vezes, com intervalo de 15 dias entre os testes, 11 futebolistas masculinos. Todos eram de alto nível, treinava [...] m em média 10 horas por semana subdivididos em treinamentos físicos, técnicos, táticos e jogos competitivos, totalizando cinco vezes por semana e na fase em que foram avaliados se encontravam em pleno período competitivo realizando um jogo por semana. Os futebolistas foram avaliados em esteira ergométrica (1,2 km.h-1) a cada dois minutos e inclinação fixa durante o teste em 3%. O VO2max foi medido diretamente utilizando analisador metabólico de análise de gases expirados respiração-a-respiração. RESULTADOS: A velocidade máxima de corrida e o VO2max atingido nos dois testes foram respectivamente: (15,6 ± 1,1 vs. 15,7 ± 1,2 km.h-1; [p = 0,78]) e (54,5 ± 3,9 vs. 55,2 ± 4,4 ml.kg-1.min-1; [P = 0,88]). Houve correlação significante e alta do VO2max entre os dois testes após 15 dias de intervalo [r = 0,97; P Abstract in english OBJECTIVE: To determine the degree of reproducibility of maximum oxygen consumption (VO2max) among soccer players, using a modified Heck protocol. METHODS: 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance leve [...] l; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3% during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. RESULTS: The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 ± 1.1 vs. 15.7 ± 1.2 km.h-1; [P = .78]) and (54.5 ± 3.9 vs. 55.2 ± 4.4 ml.kg-1.min-1; [P = .88]). There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P

  20. Distribución de biomasa de Barleria lupulina Lindl. en respuesta a tres regímenes de riego Biomass distribution of Barleria lupulina Lindl. in response to three watering regimes

    OpenAIRE

    Paz, V; Vera, A.; Páez, A.

    2003-01-01

    Barleria lupulina es un planta con propiedades medicinales potenciales, cuya acumulación de fitomasa, a nivel de sus órganos, ha sido poco investigada. Se determinó la distribución de biomasa de B. lupulina Lindl. en respuesta a tres regímenes de riego. Se diseñaron, por triplicado, tres tratamientos de riego: cada 2 (RI), 5 (RII) y 15 (RIII) días. Se realizaron mediciones del contenido relativo de agua (CRA), el potencial hídrico, y determinaciones de área foliar y biomasa seca a los seis me...

  1. LA SUSTITUCIÓN DE LA SABANA NATIVA POR PLANTACIONES DE PINO Y LA VARIABILIDAD TEMPORAL EN LA BIOMASA MICROBIANA Y LA MINERALIZACIÓN DEL CARBONO Y NITRÓGENO EN EL SUELO

    Directory of Open Access Journals (Sweden)

    Yrma G\\u00F3mez

    2010-01-01

    biomasa microbiana presente en la plantación de pino, así como la menor actividad ineralizadora del C y el N en esta plantación, sugieren, que una mayor preservación de estos nutrientes ocurre en pinares; lo cual favorece la calidad del suelo. La dinámica temporal de la biomasa microbiana en la sabana nativa y en la plantación de pino no está acoplada a la variación temporal de la mineralización del C y el N de estos sistemas.

  2. Validade preditiva da medida e estimativas do VO2máx no desempenho de Mountain Bikers / Predictive validity of VO2máx measurement and estimates in Mountain Bikers' performance / Validez predictiva de la medida y estimativas del VO2máx en el desempeño de Mountain Bikers

    Scientific Electronic Library Online (English)

    Fernanda, Mainardi; Allan, Inoue; Fernando Augusto de Saboia, Pompeu; Tony Meireles, Santos.

    2015-02-01

    Full Text Available INTRODUÇÃO: considerando o racional para a utilização das equações preditivas na estimativa do VO2máx em atletas, nenhum estudo estabeleceu sua validade para o desempenho no mountain bike cross-country (XCO). OBJETIVO: comparar diferentes estratégias de determinação do VO2máx, de forma direta ou in [...] direta, para a predição do desempenho em uma prova real e outra simulada. MÉTODOS: 20 atletas de XCO do sexo masculino (31,6 ± 6,8 anos; 68,1 ± 6,5 kg; 175,5 ± 5,7cm; 64,9 ± 4,4 mL. kg-1.min-1), foram submetidos a três sessões experimentais. A primeira visita consistiu na estratificação de risco, avaliação antropométrica e teste progressivo máximo. Na segunda, foi realizada a prova simulada e, na terceira, foi realizada a competição de XCO. RESULTADOS: a correlação entre a prova simulada e as equações preditivas do VO2máx de forma absoluta alcançaram relação quase perfeita (r ? 0,9). As correlações entre a competição real e as estimativas de VO2máx relativizadas à massa corporal alcançaram resultados classificados como muito altos (r = 0,7-0,89). As associações entre a medida direta do VO2máx e a simulação apresentaram uma classificação baixa para valores relativos à massa corporal (r = 0,10, IC95% -0,35 a 0,51). Para o desempenho real, a classificação foi moderada (r = 0,48, IC95% 0,009 a 0,78). CONCLUSÃO: o presente estudo foi o primeiro a demonstrar a validade preditiva das estimativas do VO2máx para o desempenho simulado e real de MTB. Em complemento, confirmou a baixa validade preditiva da medida direta do VO2máx para o mesmo propósito. Abstract in spanish INTRODUCCIÓN: considerando el racional para el uso de las ecuaciones predictivas en la estimativa del VO2máx en atletas de ciclismo, ningún estudio estableció su validez predictiva para el desempeño en el mountain bike cross-country (XCO). OBJETIVO: comparar diferentes estrategias de determinación [...] del VO2máx, de forma directa o indirecta, para la predicción del desempeño en una prueba real y otra simulada. MÉTODOS: veinte atletas de XCO del sexo masculino (31,6 ± 6,8 años; 68,1 ± 6,5 kg; 175,5 ± 5,7cm; 64,9 ± 4,4 mL. kg-1.min-1), fueron sometidos a tres sesiones experimentales. La primera visita consistió en la estratificación de riesgo, evaluación antropométrica y test progresivo máximo. En la segunda, fue realizada la prueba simulada y en la tercera fue realizada la competición de XCO. RESULTADOS: la correlación entre la prueba simulada y las ecuaciones predictivas del VO2máx de forma absoluta alcanzaron relación casi perfecta (r ? 0,9). Las correlaciones entre la competición real y las estimativas de VO2máx relativizada a la masa corporal alcanzaron resultados clasificados como muy grande (r = 0,7-0,89). Las asociaciones entre la medida directa del VO2máx y la simulación presentaron clasificación pequeña para valores relativos a masa corporal (r = 0,10, IC95% -0,35 a 0,51). Para el desempeño real, la clasificación fue moderada (r = 0,48, IC95% 0,009 a 0,78). CONCLUSIÓN: el presente estudio fue el primero en demostrar la validez predictiva de las estimativas del VO2máx para el desempeño simulado y real de MTB. En complemento, confirmó la baja validez predictiva de la medida directa del VO2máx para el mismo propósito. Abstract in english INTRODUCTION: considering the rationale for the use of predictive equations to estimate VO2max in athletes, no study has established its validity for performance in mountain bike cross-country (XCO). OBJECTIVE: the aim was to compare different strategies for determining VO2max, directly or indirect [...] ly, for predicting performance in a simulated and in a real competition. METHODS: 20 XCO male athletes (31.6 ± 6.8 anos; 68.1 ± 6.5 kg; 175.5 ± 5.7cm; VO2max 64.9 ± 4.4 mL. kg-1.min-1), were submitted to three experimental sessions. In the first visit, there were risk stratification, anthropometric evaluation and maximum progressive test. In the second, a simulated race was performed and, in the third s

  3. Control de una planta prototipo de gasificación de biomasa mediante redes neuronales

    Scientific Electronic Library Online (English)

    Carlos A., Forero Núñez; José U., Castellanos Contreras; Fabio E., Sierra Vargas.

    Full Text Available Los sistemas de gasificación de Biomasa son una alternativa para emplear residuos agroindustriales y generar un combustible gaseoso; sin embargo, estos procesos no lineales se ven afectados por las características típicas del material y por la variación en las temperaturas al interior del equipo, po [...] r lo tanto se requieren sistemas de control para alcanzar estados estables en el tiempo. Este trabajo analiza el desempeño de un control mediante redes neuronales aplicado a un gasificador de lecho fijo corriente descendente cuando se emplean cascaras de coco o cuesco de palma. Los resultados indican que el uso del sistema de control en el equipo, alimentado con cascaras de coco, permite aumentar las temperaturas en el reactor de 600°C a 800°C en la zona de inyección, superando así el problema derivado de la baja transferencia de energía por conducción a través del sistema. Cuando se emplea el control en la gasificación de cuesco, la temperatura promedio se mantuvo constante en 790°C, el CO presente en el gas estuvo alrededor de 10% mientras que el CO2 disminuyó a 4%. La aplicación de un sistema de control mediante redes neuronales es una gran alternativa puesto que se puede entrenar para cada tipo de biomasa mejorando la estabilidad del sistema y produciendo un gas de síntesis con menor contenido de CO2. Esto para un país con gran diversidad de recursos agroindustriales abre la posibilidad de usar estos subproductos en la generación de energía a partir de fuentes renovables. Abstract in english The gasification power systems are a remarkable alternative because they can use agro-industrial wastes to produce clean syngas; although, the differences between the biomass properties and the inner temperatures throughout the equipment make compulsory the use of control systems to achieve stable s [...] tates. This work aims to analyze the effect of applying a Neural Network Control System on a Downdraft fixed bed gasifier fed with Coconut shells and Oil Palm shells. Results show that the use of the control system on the equipment fed with coconut shells increased the maximum temperature at the air injection zone from 600°C to 800°C, which overcomes the problems found by the low thermal conductivity of the coconut shells. With the control system and the equipment fed with oil palm shells, the maximum temperature was 790°C; the CO in the syngas was stable at 10%, whereas the CO2 decreased to 4%. The Neural Network control system is useful because this can be trained for each biomass, resulting on stable temperatures and low CO2 syngas. This improves the chances of producing energy from renewable resources in a country with a lot of agro-industrial byproducts like Colombia.

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

    OpenAIRE

    E. J. Aguirre-Ezkauriatza; A. Ram\\u00EDrez-Medrano; J. M. Aguilar-Y\\u00E1\\u00F1ez; M. M. \\u00C1lvarez

    2009-01-01

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

  5. 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)

    Rosa de Lourdes Romo Campos

    2009-01-01

    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.

  6. The Effect of Habitual Smoking on VO2max

    Science.gov (United States)

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

    2008-01-01

    VO2max is associated with many factors, including age, gender, physical activity, and body composition. It is popularly believed that habitual smoking lowers aerobic fitness. PURPOSE: to determine the effect of habitual smoking on VO2max after controlling for age, gender, activity and BMI. METHODS: 2374 men and 375 women employed at the NASA/Johnson Space Center were measured for VO2max by indirect calorimetry (RER>=1.1), activity by the 11 point (0-10) NASA Physical Activity Status Scale (PASS), BMI and smoking pack-yrs (packs day*y of smoking). Age was recorded in years and gender was coded as M=1, W=0. Pack.y was made a categorical variable consisting of four levels as follows: Never Smoked (0), Light (1-10), Regular (11-20), Heavy (>20). Group differences were verified by ANOVA. A General Linear Models (GLM) was used to develop two models to examine the relationship of smoking behavior on VO2max. GLM #1(without smoking) determined the combined effects of age, gender, PASS and BMI on VO2max. GLM #2 (with smoking) determined the added effects of smoking (pack.y groupings) on VO2max after controlling for age, gender, PASS and BMI. Constant errors (CE) were calculated to compare the accuracy of the two models for estimating the VO2max of the smoking subgroups. RESULTS: ANOVA affirmed the mean VO2max of each pack.y grouping decreased significantly (psmoking exposure increased. GLM #1 showed that age, gender, PASS and BMI were independently related with VO2max (R2 = 0.642, SEE = 4.90, pSmoked, the effects on VO2max from Light and Regular smoking habits were -0.83 and -0.85 ml.kg- 1.min-1 respectively (peffect of Heavy smoking on VO2max was -2.56 ml.kg- 1.min-1 (psmoking group in GLM #2 was smaller than the CE s of the smoking group counterparts in GLM #1. CONCLUSIONS: After accounting for the effects of gender, age, PASS and BMI the effect of habitual smoking on reducing VO2max is minimal, about 0.85 ml/kg/min, until the habit exceeds 20 pack.y at which point an additional decrease of 1.71 ml/kg/min is noted. Adding pack.y data improves the accuracy of predicting the VO2max of smokers.

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

    Directory of Open Access Journals (Sweden)

    José C. Villar

    2008-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jorge Ignacio del Valle

    2011-09-01

    Full Text Available 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 estimamos 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 26.7Biomass 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 conducted 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<5cm of all woody plants. We estimated the biomass of pastures by harvesting 54 plots of 2mx2m, and of shrubs in the fallows by harvesting the biomass in 18 plots of 5mx2m. We modeled Bav (above ground live biomass of woody plants and Brg (coarse root biomass as a function of succesional age (t with the growth model of von Bertalanffy, using 247t/ha and 66t/ha as asymptote, respectively. Besides, we modeled the ratios brg/bav=f(D and Brg/Bav=f(t. The model estimated that 87 years are required to recover the existing Bav of primary forests through secondary succession, and 217 years for the Brg of the primary forest. The maximum instantaneous growth rate of the Bav was 6.95 t/ha/yr at age 10. The maximum average growth rate of the Bav was 6.26 t/ha/yr at age 17. The weighted average of the absolute growth rate of the Bav reached 4.57t/ha/yr and the relative growth rate 10% annually. The ratio brg/bav decreases with increasing D. The ratio Brg/Bav initially increases very rapidly until age 5 (25%, then decreases to reach 25 years (18% and increases afterwards until the ratio reaches the asymptote (26.7%. Rev. Biol. Trop. 59 (3:1337-1358. Epub 2011 September 01.

  9. 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).

  10. The VO-5 blower for coal industry and agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Raskin, I.A.; Ivanov, S.K.; Karminskii, V.N.

    1984-01-01

    This article discusses design and performance testing of the VO-5 blower developed by the im. Vakhrushev electromechanical plant in Tomsk. The VO-5 is used at working places where explosion-proof housing is unnecessary. In comparison to the SVM-5M2 blower the VO-5 weighs 30% less and is 0.74% more efficient. The VO-5 with a rated power of 5.5 kW and capacity of 3.1 m/SUP/3/s produces a pressure of 125 daPa. The VO-5 weighs 125 kg, is 660 mm high and 595 mm wide. The designed mean-time-between-failures is 4,500 h (in comparison to 3,000 h of the SVM-5M2 blower), the actual mean-time-between-failures is more than 10,000 h. Noise level of the VO-5 is relatively low and does not exceed 85 dB. Aerodynamic characteristics of the VO-5 and the SVM-5M2 are given in a diagram.

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

    Science.gov (United States)

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

    2012-09-01

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

  12. The VO-Neural project: recent developments and some applications

    CERN Document Server

    Brescia, M; d'Angelo, G; D'Abrusco, R; Deniskina, N; Garofalo, M; Laurino, O; Longo, G; Nocella, A; Skordovski, B

    2008-01-01

    VO-Neural is the natural evolution of the Astroneural project which was started in 1994 with the aim to implement a suite of neural tools for data mining in astronomical massive data sets. At a difference with its ancestor, which was implemented under Matlab, VO-Neural is written in C++, object oriented, and it is specifically tailored to work in distributed computing architectures. We discuss the current status of implementation of VO-Neural, present an application to the classification of Active Galactic Nuclei, and outline the ongoing work to improve the functionalities of the package.

  13. K3VO2(V2As2O12

    Directory of Open Access Journals (Sweden)

    Ahmed Driss

    2009-05-01

    Full Text Available A new potassium vanadium arsenate, tripotassium trivanadium bis(arsenate hexaoxide, K3VO2(V2As2O12, was synthesized by a solid-state reaction at 743?K. The structure is built up from VO5 pyramids, VO4 tetrahedra (.m. symmetry and AsO4 tetrahedra linked together by corner-sharing to form a three-dimensional framework. The two crystallographically independent K+ cations, one of which has .m. symmetry, are located in the interconnected tunnels running along the a and b directions.

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

    Science.gov (United States)

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

    2010-01-01

    Maximal oxygen consumption (VO2max) is the "gold standard" by which to assess functional capacity; however, it is effort dependent. VO2@RER1.0 is defined when VO2 = VCO2. Between December 22, 1997 and November 9, 2004, 305 pediatric subjects underwent cycle ergometer cardiopulmonary exercise testing, exercised to exhaustion, and reached a peak respiratory exchange ratio > or = 1.10. Group 1 subjects achieved a peak VO2 > or = 80% of predicted VO2max; group 2 subjects achieved a peak VO2 VO2max; and group 3 subjects achieved a peak VO2 between 61 and 79% of predicted VO2max. Linear regression analysis was performed for VO2@RER1.0 as a function of predicted VO2 for group 1 subjects. A -2 SD regression line and equation was created. VO2@RER1.0 data from groups 2 and 3 were plotted onto the normative graph. Contingency table and relative-risk analysis showed that an abnormal VO2@RER1.0 predicted an abnormal peak VO2(positive-predictive value 83%, negative-predictive value 85%, sensitivity 84%, and specificity 84%). VO2@RER1.0 is a highly sensitive, specific, and predictive submaximal index of functional capacity. This submaximal index is easy to identify without subjectivity. This index may aid in the evaluation of subjects who cannot exercise to maximal parameters. PMID:19812880

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

    Science.gov (United States)

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

    2015-09-01

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

  16. Audio CAPTCHA for SIP-Based VoIP

    Science.gov (United States)

    Soupionis, Yannis; Tountas, George; Gritzalis, Dimitris

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

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

    Science.gov (United States)

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

    2015-06-01

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

  18. The Astrophysical Virtual Observatory to EURO-VO Transition

    OpenAIRE

    PADOVANI, P

    2005-01-01

    The Astrophysical Virtual Observatory (AVO) initiative, jointly funded by the European Commission and six European organisations, had the task of creating the foundations of a regional scale infrastructure by conducting a research and demonstration programme on the VO scientific requirements and necessary technologies. The AVO project is now formally concluded. I highlight AVO's main achievements and then describe its successor, the EURO-VO project. With its three new interl...

  19. Stredoveké mestské opevnenia na Slovensku

    Directory of Open Access Journals (Sweden)

    Alexandra Škrinárová

    2013-12-01

    Full Text Available Stredoveké mestské opevnenia patria k najvýznamnejším a najstarším pamiatkam historických miest. Aj napriek svojmu torzálnemu stavu zachovania sú zdrojom poznania a charakteristickým prvkom stredovekého urbanizmu. Plnia dôležitú úlohu vo fonde nášho kultúrneho dedi?stva ale doposia? im u nás nebola venovaná systematická pozornos?. Príspevok sa venuje predmetu a cie?om výskumu stredovekých mestských opevnení, sú?asnému stavu ich poznania a ?iastkovým výsledkom na príklade opevnenia v meste Sabinov.

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

    Scientific Electronic Library Online (English)

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

    2014-03-01

    Full Text Available En este artículo se discute la relación existente entre la enfermedad pulmonar obstructiva crónica (EPOC) y el humo de biomasa. Más de la mitad de la población utiliza biomasa como combustible principal, sobre todo en áreas rurales y en países en vías de desarrollo donde su uso llega hasta el 80%. 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

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

    Scientific Electronic Library Online (English)

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

    2014-01-01

    Full Text Available En este artículo se discute la relación existente entre la enfermedad pulmonar obstructiva crónica (EPOC) y el humo de biomasa. Más de la mitad de la población utiliza biomasa como combustible principal, sobre todo en áreas rurales y en países en vías de desarrollo donde su uso llega hasta el 80%. 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

  2. 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)

    Magalis, Zabala; Yrma, Gómez.

    2010-09-01

    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 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.

  3. 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)

    Ángel Canales-Gutiérrez

    2010-01-01

    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.

  4. 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)

    Marisol GALLEGOS-GARCÍA

    2010-01-01

    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.

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

    CERN Document Server

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

    2014-01-01

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

  6. Influência do estado nutricional e do VO2max nos níveis de adiponectina em homens acima de 35 anos

    Directory of Open Access Journals (Sweden)

    Eduardo Camillo Martinez

    2011-06-01

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

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

    OpenAIRE

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

    2008-01-01

    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 vi...

  8. VoLTE performance in railway scenarios

    DEFF Research Database (Denmark)

    Sniady, Aleksander; SØnderskov, Morten

    2015-01-01

    GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services. Examples of Railway Emergency Call and One-to-One Call are provided. Service performance, in terms of call setup times and voice transmission quality, is analyzed in simulation scenarios modelling two railway scenarios in Denmark.

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

    Directory of Open Access Journals (Sweden)

    Torrente Trujillo Armando

    2011-03-01

    Full Text Available

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

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

  10. Análisis de biomasa del vuelo de un rodal adulto de Pinus radiata Analysis of aboveground biomass in a mature stand of Pinus radiata

    Directory of Open Access Journals (Sweden)

    CLAUDIO MUÑOZ RIVEROS

    2005-12-01

    Full Text Available Se realizó un estudio de biomasa en árboles de Pinus radiata D. Don de 42 años, obtenidos de un rodal ubicado entre las ciudades de Santa Juana y Nacimiento, VIII Región, Chile. El rodal se diferenció en tres clases de copa: dominante, codominante e intermedio. En cada clase de copa se obtuvieron valores de biomasa para cada componente (madera, corteza, ramas, ramillas y acículas; la madera resultó ser el componente que más aportó a la biomasa total sobre el suelo (88,9%, seguido de la corteza (8,2% y ramas (1,5%. Con los valores de biomasa obtenidos, se ajustaron funciones de biomasa por componente, relacionando estos valores con variables del árbol; el dap (diámetro a la altura del pecho y el dbc (diámetro en la base de la copa viva fueron las variables que mostraron mayor correlación con los valores de biomasa por componente y menores errores de estimación.A study of biomass in Pinus radiata D. Don with 42 years old was made, the trees were obtained of a stand placed between the cities of Santa Juana and Nacimiento, VIII Region, Chile. Three classes of top were differentiated in the stand: dominant, codominant and intermediate. The value of the mass for each component (wood, bark, branches, branchlets and needle was obtained from each class of top; the wood resulted as the most important component in the total biomass of the tree (88.9%, then the bark (8.2% and branches (1.5%. Obtained the values of biomass, the function of biomass for each component was obtained, related this values with the variables of the tree; the variables that showed greater correlation with the values of biomass by component and minors estimation errors are dbh (breast height diameter and dbc (base of live crown diameter.

  11. Determinación de las reservas de carbono de la biomasa aérea, en diferentes sistemas de uso de la tierra en San Martín, Perú

    Directory of Open Access Journals (Sweden)

    Tatiana Lapeyre

    2004-01-01

    Full Text Available Se determinó la biomasa aérea en diferentes sistemas de uso de la tierra en la región de San Martín-Perú, con la finalidad de conocer el potencial de captura de carbono. Los sistemas de uso de la tierra evaluados fueron: Bosque primario, Bosque secundario de diferentes edades, sistemas agrícolas locales maíz (Zea maiz, arroz (Oriza Sativa, pastos (Brachiaria y sistemas agroforestales con café (Coffea arabica bajo sombra y cacao (Cacao sp.. También se comparó este potencial con otros sistemas de uso de la tierra de otras regiones del Perú y se monitoreó la pérdida de reservas de carbono después del corte de la foresta y su reemplazo por cultivos. En cada uno de éstos sistemas se establecieron al azar cinco transectos donde se evaluó la biomasa arbórea. Dentro de éstos transectos se establecieron cuadrados también al azar para cuantificar la biomasa herbácea y la biomasa de hojarasca. El carbono total en el bosque primario fue de 485 tm C ha-1, superando ampliamente las reservas del bosque secundario de 50 años y de bosque descremado de 20 años. Con relación al bosque primario se observa una reducción de reservas en más de 50% del bosque secundario de 50 años (234 tm C ha-1. El bosque descremado de 20 años perdió más del 80% de reservas (62 tm C ha-1. El nivel de reservas de carbono en la biomasa de hojarasca de los sistemas boscosos, no es significativo al compararlo con el total de las reservas de carbono de la biomasa aérea; sin embargo si es significativo para sistemas agroforestales. Los sistemas agroforestales secuestraron entre 19 a 47 tm C ha-1, dependiendo de la cantidad de especies forestales, tipo de cultivo, edad y tipo de suelo y recuperan el potencial de captura en forma productiva. Los sistemas agrícolas capturaron poco C (5 tm C ha-1, además generan fugas de gases efecto invernadero (GEI cuando se usan agroquímicos y quema de rastrojos, entre otros.

  12. 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)

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

    2005-06-01

    Full Text Available A importância das qualidades morfofuncionais na melhora do rendimento nos esportes aumentou o interesse no aprimoramento dos níveis de aptidão física dos atletas. No entanto, há poucos estudos sobre as variáveis fisiológicas do futsal disponíveis na literatura científica mundial. Dessa forma, o 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 measurement, the computerized ergospirometric system was us

  13. Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition

    International Nuclear Information System (INIS)

    Highlights: • Vanadium dioxide was successfully synthesized by pulsed laser deposition method on mica. • The morphology evolution within the samples is characterized by a change from isolated and less-percolating (0 1 1) VO2 crystallites to a percolating granular configuration. • Without any post annealing, the films exhibit a textured nature with a VO2 (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio RS/RM through the SMT at T ? 68 °C of the order of 104 and a narrow ?7 °C hysteresis. - Abstract: VO2 thin films have been deposited by pulsed laser deposition on Zinnwaldite Mica substrates. The crystal structure, chemical composition, morphology were determined and the semiconductor/metal transition (SMT) properties of the deposited films were investigated. Without any post annealing, the films exhibit a textured nature with a VO2 (0 1 1) preferred crystallographic orientation and an elevated thermal variation of the electric resistance ratio RS/RM through the SMT at T ? 68 °C of the order of 104 and a narrow ?7 °C hysteresis. In addition, the growth of the VO2 crystallites seem to be governed likely by a Volmer-Weber or Stranski-Krastanov mechanisms and certainly not a Frank-van Der Merwe process

  14. Structural characterization of PrVO3 epitaxial thin films

    CERN Document Server

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

    2014-01-01

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

  15. 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)

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

    Full Text Available 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.

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

    OpenAIRE

    Bereka Shewara, Jemil

    2012-01-01

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

  17. Urchin-like m-LaVO{sub 4} and m-LaVO{sub 4}/Ag microspheres: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Limiao, E-mail: chenlimiao@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Wu, Min; Wang, Dan; Zhou, Le; Yu, Na; Zhang, Peisen; Huang, Jianhan [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Liu, Xiaohe, E-mail: liuxh@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Qiu, Guanzhou [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China)

    2014-12-15

    The semiconductor nanostructures decorated with noble metals have attracted increasing attention due to their interesting physical and chemical properties. In this work, urchin-like monoclinic (m-) LaVO{sub 4} microspheres were prepared by a hydrothermal method and used as a template to fabricate Ag nanoparticle-decorated m-LaVO{sub 4} composites. The morphology and structure were characterized by transmission electron microscope, high-resolution transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray. It was found that Ag nanoparticles with narrow size distribution were uniformly loaded on urchin-like m-LaVO{sub 4} microspheres, and the resulted composite microspheres showed distinct surface plasmon absorption band compared to pure m-LaVO{sub 4} microspheres. Photocatalytic activities of as-prepared samples were examined by studying the degradation of methyl orange solutions under visible-light irradiation (> 400 nm). Results clearly showed that urchin-like m-LaVO{sub 4}/Ag microspheres possess much higher photocatalytic activity than pure m-LaVO{sub 4} microspheres and P25. - Highlights: • m-LaVO{sub 4}/Ag composites microspheres were fabricated by a hydrothermal method. • m-LaVO{sub 4} microspheres show higher photocatalytic activity than m-LaVO{sub 4} microspheres. • m-LaVO{sub 4}/Ag microspheres exhibit a good stability.

  18. Epitaxial Growth of VO$_{2}$ by Periodic Annealing

    OpenAIRE

    Tashman, J. W.; Lee, J.H.; Paik, H; Moyer, J. A.; Misra, R.; Mundy, J. A.; Spila, T.; Merz, T. A.; Schubert, J.; Muller, D. A.; Schiffer, P.; D. G. Schlom

    2013-01-01

    We report the growth of ultrathin VO$_{2}$ films on rutile TiO$_{2}$ (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$_{2}$ via solid-phase epitaxy. Significant metal-insulator transitions were observed in films as thin as 2.3 nm, where a resistance change {\\Delta}R/R of 25 was measured. Low angle annular dark field scanning transmission electron ...

  19. Infrared-sensitive electrochromic device based on VO2

    Science.gov (United States)

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

    2013-10-01

    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.

  20. Metodología de diseño e implementación de soluciones voIP

    Directory of Open Access Journals (Sweden)

    Wilson A. Bulla B.

    2012-12-01

    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.

  1. Lightweight security mechanism for PSTN-VoIP cooperation

    CERN Document Server

    Mazurczyk, W; Mazurczyk, Wojciech; Kotulski, Zbigniew

    2006-01-01

    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.

  2. Caracterización del bagazo de caña como biomasa vegetal / Characterization of the cane bagasse like vegetable biomass

    Scientific Electronic Library Online (English)

    Enma M., Manals-Cutiño; Margarita, Penedo-Medina; Dolores, Salas-Tort.

    2015-08-01

    Full Text Available Este trabajo tiene como finalidad evaluar propiedades físicas y químicas de diferentes clases de tamaño de muestras de bagazo de caña, como parte del estudio de descomposición térmica de las mismas. Para la realización del análisis granulométrico del bagazo de caña se estudiaron dos muestras; obteni [...] éndose una distribución muy variada, desde un fino polvo hasta partículas irregulares de gran tamaño, las mayores acumulaciones fueron obtenidas para partículas menores de 0,5 mm y hasta 1mm de diámetro. En este estudio se desarrollaron dos métodos: el Método Diferencial y el Método Acumulativo, obteniéndose diámetros promedio de las muestras aproximadamente iguales por ambos métodos, de manera que el diámetro promedio del bagazo de caña en general es de 0,453 mm. Aplicando la metodología experimental y en las instalaciones adecuadas se evaluaron las propiedades químicas de la biomasa estudiada: carbono fijo, volátiles, cenizas, humedad. Luego se determinó la influencia del tamaño de las partículas en las propiedades del bagazo de caña obteniéndose que para la humedad y el carbono fijo no existe una tendencia definida en estos parámetros. En el caso del contenido de volátiles existe una tendencia al aumento de este contenido con el aumento del diámetro de las partículas, ocurriendo lo contrario para el contenido de cenizas. Se obtuvo una diferencia estadísticamente significativa entre la media de cada uno de estos parámetros entre un nivel de Dpi y otro, excepto para el caso del carbono fijo. Abstract in english In this work were evaluated physical and chemical properties of different classes of size of samples of bagasse cane, like part of the study of thermal decomposition of the same ones. Two samples were studied; being obtained a very varied distribution, from a fine powder until irregular particles of [...] great size, the biggest accumulations were obtained for particles smaller than 0,5mm and up to 1mm of diameter. In this study two methods were developed: the Differential Method and the Accumulative Method, being obtained diameters average of the approximately same samples by both methods, so that the diameter average of the bagasse cane in general is of 0,453mm. Applying the experimental methodology and in the appropriate facilities the chemical properties of the studied biomass were evaluated: fixed, volatile, ashy carbon, humidity. Then the influence of the size of the particles was determined in the properties of the cane trash being obtained that for the humidity and the fixed carbon doesn't exist a tendency defined in these parameters. In the case of the content of volatile a tendency exists to the increase of this content with the increase of the diameter of the particles, happening the opposite for the content of ashy. A difference was obtained statistically significant among the stocking of each one of these parameters among a level of Dpi and other, except for the case of the fixed carbon.

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

    Science.gov (United States)

    Zwiren, Linda D.; And Others

    1991-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Juanita Y. Concha

    2007-01-01

    Full Text Available 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 establecieron aleatoriamente cinco cuadrantes de 100 m2 cada uno, evaluándose la biomasa vegetal total existente. Para evaluar la ecuación alométrica del cacao se muestrearon 7 plantas cuyas edades variaron de 01 hasta 22 años. Loas resultados en captura de carbono en cada sistema agroforestal varían desde 26.2 t C ha-1para el sistema de Pachiza de 5 años hasta 45.07 t C ha-1del sistema agroforestal de Pachiza de 12 años; Así mismo, la captura de carbono en biomasa arbórea de los árboles vivos, osciló desde 12.09 t ha-1 hasta 35.5 t ha-1, seguido por la biomasa de hojarasca que presentaron valores desde 4 t ha-1 hasta 9.97 t ha-1; mientras la biomasa de árboles muertos en pie y caídos muertos presentaron valores muy variables y bajos. Los sistemas agroforestales de 12 y 20 años representan el 66.7% de los sistemas que presentan reservas de carbono por encima de los 40 t C ha-1; mientras que los sistemas de 5 años se encuentran con reservas de carbono por debajo de los 30 t C ha-1. Los sistemas agroforestales de 5 años ubicados en Juanjui y Pachiza presentaron el mayor flujo de carbono anual, generando el mayor beneficio económico con créditos por CO2 equivalente

  5. Microstructure of orientation controlled VO2 thin films via ZnO buffer

    International Nuclear Information System (INIS)

    B-axis preferential oriented VO2 thin films were prepared on glass substrates via ZnO buffers by pulsed laser deposition. In order to explore the relationship between the VO2 and ZnO layers, cross-sectional images of the orientation-controlled VO2 thin films were examined using a transmission electron microscope (TEM). As revealed by the TEM images, for the VO2 thin films deposited on a relatively thick ZnO buffer (? 70 nm), an interface layer was formed between the VO2 and ZnO layers. The interface layer was identified as V3O5 based on X-ray photoelectron spectra (XPS) and high resolution TEM images. For the VO2 thin films deposited on a 5-nm thick ZnO buffer, only a b-axis oriented VO2 layer was observed. The b-axis oriented VO2 layer displayed a columnar structure, and the layer thickness was occupied by one grain. However, TEM images of the thicker VO2 thin films (? 90 nm) deposited on 5-nm ZnO buffer revealed a VO2 (111) facet on the grain and amorphous residues of VO2. These results indicated that the grains of VO2 grew from the interface with the ZnO buffer, and the grain growth was slower than the speed of deposition. - Highlights: ? B-axis oriented VO2 thin films were prepared on glass on ZnO buffer layers. ? Transmission electron microscopy confirms the formation of an interface layer. ? X-ray photoelectron spectroscopy data reveal a V3O5 interface layer. ? VO2 (111) facet on grains and amorphous residues of VO2 were observed. ? The grain growth was slower than the rate of deposition

  6. 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)

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

    2011-07-01

    Full Text Available 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.

  7. Direct and continuous synthesis of VO2 nanoparticles

    Science.gov (United States)

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

    2015-11-01

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

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

    Index Scriptorium Estoniae

    Brodneva, Jevgenia

    2003-01-01

    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..."

  9. Upcoming Features of SPLAT-VO in Astroinformatics.

    Czech Academy of Sciences Publication Activity Database

    Šaloun, P.; Andreši?, D.; Škoda, Petr; Zelinka, I.

    Vol. 210. Cham : Springer, 2013, s. 475-486 ISBN 978-3-319-00541-6. ISSN 2194-5357. [Nostradamus 2013. Ostrava (CZ), 03.06.2013-05.06.2013] R&D Projects: GA ?R GA13-08195S Institutional support: RVO:67985815 Keywords : SPLAT-VO * spectrum analysis * SAMP Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-01

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

  11. 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)

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

    2008-06-01

    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 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 (

  12. Current Status of VO Compliant Data Service in Japanese Virtual Observatory

    Science.gov (United States)

    Shirasaki, Y.; Komiya, Y.; Ohishi, M.; Mizumoto, Y.; Ishihara, Y.; Tsutsumi, J.; Hiyama, T.; Nakamoto, H.; Sakamoto, M.

    2012-09-01

    In these years, standards to build a Virtual Observatory (VO) data service have been established with the efforts in the International Virtual Observatory Alliance (IVOA). We applied these newly established standards (SSAP, TAP) to our VO service toolkit which was developed to implement earlier VO standards SIAP and (deprecated) SkyNode. The toolkit can be easily installed and provides a GUI interface to construct and manage VO service. In this paper, we describes the architecture of our toolkit and how it is used to start hosting VO service.

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

    OpenAIRE

    Zhang, Ge

    2010-01-01

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

  14. 76 FR 59916 - Interconnected VoIP Service; Wireless E911 Location Accuracy Requirements; E911 Requirements for...

    Science.gov (United States)

    2011-09-28

    ...interconnected VoIP service providers to automatically...regulations to VoIP services that are not fully...limitations for use in next generation public safety applications...for nomadic VoIP services; and consider extending...providers of over-the-top VoIP...

  15. Synthesis of novel photocatalytic RGO-InVO{sub 4} nanocomposites with visible light photoactivity

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jianfeng; Li, Xianfu [Department of Materials Science, Fudan University, Shanghai, 200433 (China); Huang, Weishi; Li, Na [Center of Special Materials and Technology, Fudan University, Shanghai, 200433 (China); Ye, Mingxin, E-mail: mxye@fudan.edu.cn [Department of Materials Science, Fudan University, Shanghai, 200433 (China); Center of Special Materials and Technology, Fudan University, Shanghai, 200433 (China)

    2013-09-01

    Graphical abstract: A facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO{sub 4}) photocatalysts is reported. The visible light response and adsorption ability of RGO-InVO{sub 4} nanocomposites is greatly improved, which can effectively remove methyl orange and Cr (VI) from water. - Highlights: • Supramolecular photocatalyst of RGO-InVO{sub 4} was achieved. • Reduction of GO and preparation of RGO-InVO{sub 4} was simultaneous. • The prepared RGO-InVO{sub 4} shows high photocatalytic activity and adsorption capacity under visible light. • In situ growth of uniform InVO{sub 4} particles on RGO sheets is facile and efficient - Abstract: In this study, we report a facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO{sub 4}) photocatalysts. A wide range of characterization techniques, such as Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, Thermogravimetric analysis and Transmission electron microscopy were applied to characterize the obtained composites. The results indicated that the composites consist of uniformly dispersed InVO{sub 4} nanocrystals on RGO sheets. Visible light responses of RGO-InVO{sub 4} nanocomposites are greatly improved as compared with the bulk InVO{sub 4}. The as-prepared RGO-InVO{sub 4} nanocomposites can effectively remove methyl orange and Cr (VI) from water under visible light irradiation, which can be used as novel photocatalysts for environmental protection.

  16. Synthesis of novel photocatalytic RGO-InVO4 nanocomposites with visible light photoactivity

    International Nuclear Information System (INIS)

    Graphical abstract: A facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO4) photocatalysts is reported. The visible light response and adsorption ability of RGO-InVO4 nanocomposites is greatly improved, which can effectively remove methyl orange and Cr (VI) from water. - Highlights: • Supramolecular photocatalyst of RGO-InVO4 was achieved. • Reduction of GO and preparation of RGO-InVO4 was simultaneous. • The prepared RGO-InVO4 shows high photocatalytic activity and adsorption capacity under visible light. • In situ growth of uniform InVO4 particles on RGO sheets is facile and efficient - Abstract: In this study, we report a facile method for preparation of reduced graphene oxide (RGO) sheets supported indium vanadate (InVO4) photocatalysts. A wide range of characterization techniques, such as Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, Thermogravimetric analysis and Transmission electron microscopy were applied to characterize the obtained composites. The results indicated that the composites consist of uniformly dispersed InVO4 nanocrystals on RGO sheets. Visible light responses of RGO-InVO4 nanocomposites are greatly improved as compared with the bulk InVO4. The as-prepared RGO-InVO4 nanocomposites can effectively remove methyl orange and Cr (VI) from water under visible light irradiation, which can be used as novel photocatalysts for environmental protection

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

    Science.gov (United States)

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

    2016-01-01

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

  18. Synthesis, characterization and catalytic activity of two novel cis - dioxovanadium(V) complexes: [VO2(L)] and [VO2(HLox)

    International Nuclear Information System (INIS)

    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. (author)

  19. Ecuaciones de biomasa aérea para Quercus laurina y Q. crassifolia en Oaxaca / Aerial biomass equations for Quercus laurina and Q. crassifolia in Oaxaca

    Scientific Electronic Library Online (English)

    Faustino, Ruiz-Aquino; Juan Ignacio, Valdez-Hernández; Filemón, Manzano-Méndez; Gerardo, Rodríguez-Ortiz; Angélica, Romero-Manzanares; Martha Elena, Fuentes-López.

    2014-08-01

    Full Text Available La estimación de la biomasa arbórea es un medio para determinar los montos existentes de carbono orgánico en cada uno de los componentes del árbol. Los estudios sobre biomasa aérea para especies del género Quercus son escasos en México, aun cuando el país es considerado un centro de distribución. El [...] objetivo del presente trabajo fue generar ecuaciones alométricas para estimar la biomasa aérea de árboles de Quercus laurina Humb. & Bonpl. y Q. crassifolia Humb. & Bonpl., en un bosque de la comunidad de Ixtlán de Juárez, Oaxaca, México. Se muestrearon 16 árboles por cada especie, distribuidos en seis categorías diamétricas y se determinó la biomasa en fuste con corteza, ramas y follaje. Se evaluaron diferentes modelos de regresión con base en la bondad de ajuste y validez de sus indicadores estadísticos. Se eligió la ecuación exponencial de la forma Biomasa = e[-?o+?1 ln(DN2xAT)], para calcular la biomasa (kg) en función al diámetro normal (DN, cm) y altura total (AT, m) de los árboles. La biomasa aérea total se estimó en 100,15 Mg ha-1 para Q. laurina y 129,97 Mg ha-1 para Q. crassifolia. La distribución proporcional de biomasa por compartimento de Q. laurina fue 82,9%; 14,9% y 2,2% para fustes, ramas y follaje, respectivamente, mientras que para Q. crassifolia la distribución fue 82,3%; 16,0% y 1,7%; en el mismo orden. Abstract in english Estimating tree biomass is a means to determine the existing amounts of organic carbon in each of the tree components. Studies of biomass for Quercus species are scarce in Mexico, even though the country is considered a distribution center. The aim of this study was to generate allometric equations [...] for estimating aboveground biomass of trees Quercus laurina Humb. & Bonpl. and Q crassifolia Humb. & Bonpl., in a forest community of Ixtlán de Juárez, Oaxaca, México. Sixteen trees were sampled per species, distributed in six diameter categories and biomass was determined in stem bark, branches and foliage. Different regression models were evaluated based on fitness and validity of their statistical indicators. An exponential equation was chosen in the form of Biomasa = e[-?o+?1 ln(DN2xAT)], to calculate the biomass (kg) within a normal diameter (DN, cm) and total height (AT, m) of the trees. The total aboveground biomass was estimated at 100,15 Mg ha-1 for Q. laurina and 129,97 Mg ha-1 for Q. crassifolia. The proportional distribution of biomass per component of Q. laurina was 82,9%; 14,9% and 2,2% for stems, branches and foliage, respectively, while for Q. crassifolia the distribution was 82,3%; 16,0% and 1,7% in the same order.

  20. Relação entre a variabilidade da frequência cardíaca e VO 2pico em mulheres ativas / Relationship between heart rate variability and VO 2peak in active women / Relación entre la variabilidad de la frecuencia cardíaca y VO 2pico en mujeres activas

    Scientific Electronic Library Online (English)

    Nayara Yamada, Tamburús; Ana Cristina Silva, Rebelo; Marcelo de Castro, César; Aparecida Maria, Catai; Anielle Cristhine de Medeiros, Takahashi; Carolina Pieroni, Andrade; Alberto, Porta; Ester da, Silva.

    2014-10-01

    Full Text Available OBJETIVO: Ava+liar a associação entre os índices da variabilidade da frequência cardíaca (VFC) e a aptidão cardiorrespiratória. MÉTODOS: Sessenta e duas mulheres (idade 22,1 ± 3,3 anos) foram divididas em quatro grupos: treinamento aeróbio (AER, n = 15), treinamento de força (FOR, n = 13), tre [...] inamento combinado (aeróbio e força) (AER+FOR, n = 15) e controle (C, n = 19). O teste cardiopulmonar foi realizado para avaliar a aptidão cardiorrespiratória a partir do consumo de oxigênio pico (VO2pico). A FC foi coletada em repouso na postura supina. A VFC foi analisada a partir de métodos lineares e não lineares. RESULTADOS: Os grupos AER e AER+FOR apresentaram maiores índices da VFC (lineares e não lineares) indicadores da modulação vagal e menores índices da VFC indicadores da modulação simpática, em relação ao grupo C. Os grupos AER e AER+FOR apresentaram maior complexidade e menor regularidade dos intervalos RR e maior VO2pico em relação aos grupos FOR e C. O VO2pico apresentou correlação com os índices da VFC. CONCLUSÃO: Este estudo mostrou que o treinamento físico aeróbio e combinado contribuíram significativamente para maior modulação autônoma da FC e aptidão cardiorrespiratória. A modulação autônoma da FC, avaliada a partir de métodos lineares e não lineares, está associada ao maior consumo de oxigênio. Abstract in spanish OBJETIVO: Evaluar la asociación entre los índices de variabilidad de la frecuencia cardíaca (VFC) y la aptitud cardiorrespiratoria. MÉTODOS: Sesenta y dos mujeres (edad 22,1 ± 3,3 años) fueron divididas en cuatro grupos: entrenamiento aeróbico (AER, n = 15), entrenamiento de fuerza (FOR, n = 1 [...] 3), entrenamiento combinado (aeróbico y fuerza) (AER+FOR, n = 15) y control (C, n = 19). El test cardiopulmonar fue realizado para evaluar la aptitud cardiorrespiratoria a partir del consumo de oxígeno pico (VO2pico). La FC fue colectada en reposo en la postura supina. La VFC fue analizada a partir de métodos lineales y no lineales. RESULTADOS: Los grupos AER y AER+FOR presentaron mayores índices de VFC (lineales y no lineales) indicadores de la modulación vagal y menores índices de VFC indicadores de la modulación simpática, en relación al grupo C. Los grupos AER y AER+FOR presentaron mayor complejidad y menor regularidad de los intervalos RR y mayor VO2pico en relación a los grupos FOR y C. O VO2pico presentó correlación con los índices de VFC. CONCLUSIÓN: Este estudio mostró que el entrenamiento físico aeróbico y combinado contribuyeron significativamente para mayor modulación autónoma de FC y aptitud cardiorrespiratoria. La modulación autónoma de FC, evaluada a partir de métodos lineales y no lineales, está asociada al mayor consumo de oxígeno. Abstract in english OBJECTIVE: To evaluate the associations between heart rate variability (HRV) with cardiorespiratory fitness. METHODS: Sixty-two women (aged 22.1 ± 3.3) were divided into four groups: aerobic training (AER, n = 15), strength training (STR, n = 13), combined aerobic and strength training (AER+ST [...] R, n = 15) and controls (C, n = 19). Cardiopulmonary exercise testing was performed to measure cardiorespiratory fitness by assessing peak oxygen consumption (VO2peak). The HR was recorded at rest in the supine position. The HRV was analyzed by linear and nonlinear methods. RESULTS: The AER and AER+STR groups had higher vagal HRV (linear and nonlinear) indicators of vagal modulation and lower indices of HRV indicators of sympathetic modulation, compared to group C. The AER and AER+STR groups showed greater complexity and lower regularity of R-R intervals and higher peak compared to STR and C groups. The VO2peak was correlated with HRV indices. CONCLUSION: This study showed that aerobic and combined exercise significantly contributed to greater autonomic modulation of HR and cardiorespiratory fitness. The autonomic HR modulation, assessed by linear and nonlinear methods, was associated with a greater oxygen consumption.

  1. 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)

    Anirebis, Martínez Romero; Angel, Leyva Galán.

    2014-03-01

    Full Text Available La biomasa es el resultado de la transformación de la energía solar en energía química. El hombre a través de la historia la ha utilizado no solo para su alimentación sino también para la alimentación de sus animales. Los avances de la ciencia promovieron el desarrollo agrario basado en la 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.

  2. Structural and morphology comparison between m-LaVO4 and LaVO3 compounds prepared by sol-gel acrylamide polymerization and solid state reaction

    International Nuclear Information System (INIS)

    We contrast the production of LaVO3 polycrystalline samples obtained by reduction of m-LaVO4 prepared by sol-gel acrylamide polymerization (SGAP) and solid state reaction (SSR). For SGAP the formation of m-LaVO4 occurs at 400 deg. C, for SSR at 1400 deg. C. For m-LaVO4-SGAP we observe a homogeneous morphology with needle-shaped grains of 50 nm average size. The SSR presents a broader size distribution in the micrometer range. Both m-LaVO4 samples were reduced into LaVO3 using a Zr rod at 850 deg. C in vacuum. LaVO3-SGAP presents a homogeneous grain distribution with an average size of 745 nm. LaVO3-SSR has an average size of 3.45 ?m. The stoichiometry of all compounds was confirmed by energy dispersive X-ray spectroscopy. X-ray powder diffraction and transmission electron microscopy give crystal structures in agreement with those reported in the literature.

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

    Directory of Open Access Journals (Sweden)

    Romero, L.

    2011-02-01

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

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

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

    Directory of Open Access Journals (Sweden)

    María J Gualtieri A

    2007-12-01

    Full Text Available 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 propósito 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 animalThe 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

  5. Evaluación de desempeño de VoIP en redes MANET / Performance evaluation of VoIP in MANET

    Scientific Electronic Library Online (English)

    Patricia, Sing-Borrajo.

    2014-06-01

    Full Text Available Las redes MANET constituyen una opción atractiva para soluciones de VoIP en escenarios que se caracterizan por la movilidad de los nodos y donde no exista una infraestructura previamente creada. Sin embargo, el soporte de servicios de voz enfrenta desafíos más rigurosos en redes MANET que los que ap [...] arecen en otras redes. La dinámica con que cambia la topología causa que algunos parámetros importantes para medir la calidad como el retardo, la pérdida de paquetes y la variación del retardo se vean muy afectados. En este trabajo se mide mediante simulación el impacto que tienen las métricas: número de saltos, carga de tráfico, densidad de los nodos y número de interrupciones de ruta en el desempeño de aplicaciones de VoIP en redes MANET. Con los resultados obtenidos se ha podido comprobar que las métricas estudiadas tienen un comportamiento más inestable en MANET que en otras redes también candidatas a soportar servicios móviles, sin embargo, existe mucha expectativa con la posibilidad de utilizar estas tecnologías (VoIP y MANET) para ofrecer telefonía móvil de bajo costo gracias a la facilidad de despliegue y a la sencillez de su infraestructura. Abstract in english MANET networks are an attractive option for VoIP solutions in scenarios that are characterized by the mobility of nodes and where there is not a previously established infrastructure. However, the voice support faces more rigorous challenges in MANET networks than those of others networks. The dynam [...] ic with which topology changes affects important parameters to measure quality such as delay, packet loss and delay variation. In this work we measured the impact of metrics such as hop count, traffic load, node density and number of route breaks have over the performance of VoIP applications in MANET through simulation. Such simulations have allowed the comparison of the behavior of three important routing protocols. From the results reached, it has been shown that the studied metrics have a more unstable behavior in MANET than in other networks that are also candidates to carry mobile services. However, there is a lot of expectation with the possibility of using these technologies (VoIP and MANET) to provide lowcost mobile telephony due to the ease of deployment and simplicity of its infrastructure.

  6. Electrocaloric effect of metal-insulator transition in VO2

    International Nuclear Information System (INIS)

    The electrocaloric effect was observed in association with an electric-field induced metal-insulator transition in VO2 using a calorimetric measurement under an applied voltage. For a VO2 plate with a 0.4?mm thickness located in the center of a capacitor-like structure, the metal-insulator transition was manipulated by applying a few volts. The occurrence of a transition in such a thick sample with relatively low voltage indicates that a surface charge accumulation mechanism is effective. The isothermal entropy change reached 94?J kg?1 K?1, while the adiabatic temperature change was calculated as ?3.8?K under a voltage change of 0–3?V. The large entropy change is attributed to correlation of the complex freedom among spin, charge, and lattice

  7. Epitaxial growth of VO{sub 2} by periodic annealing

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  8. Epitaxial growth of VO2 by periodic annealing

    Science.gov (United States)

    Tashman, J. W.; Lee, J. H.; Paik, H.; Moyer, J. A.; Misra, R.; Mundy, J. A.; Spila, T.; Merz, T. A.; Schubert, J.; Muller, D. A.; Schiffer, P.; Schlom, D. G.

    2014-02-01

    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.

  9. 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

  10. Measurement and analysis of VoIP server performance

    OpenAIRE

    Wang, Yusong Carl

    2008-01-01

    Voice over IP (VoIP) and Instant Messaging (IM) are rapidly changing our daily communication landscape. SIP and IM protocols are two of the most widely deployed protocols for these applications. However, there are still many practical challenges toward implementing SIP and IM in commercial products, and their performances in real large-scale systems have yet to be understood and optimized. In this project, we applied two open source benchmark tools, J absimul and SIPp, to investigate the perf...

  11. Charging of SAML-based federated VoIP services

    OpenAIRE

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

    2010-01-01

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

  12. Ferroelectricity from spin supercurrents in LiCuVO4

    OpenAIRE

    Mourigal, M.; Enderle, M.; Kremer, R. K.; Law, J. M.; Fåk, B.

    2011-01-01

    We have studied the magnetic structure of the ferroelectric frustrated spin-1/2 chain material LiCuVO4 in applied electric and magnetic fields using polarized neutrons. A symmetry and mean-field analysis of the data rules out the presence of static Dzyaloshinskii-Moriya interaction, while exchange striction is shown to be negligible by our specific-heat measurements. The experimentally observed magnetoelectric coupling is in excellent agreement with the predictions of a pure...

  13. Magnetism in Ni2FeVO6-?

    International Nuclear Information System (INIS)

    The temperature dependence of magnetization M(T) of new polycrystalline ilmenite Ni2FeVO6-? shows remarkable singularities which can be interpreted as a result of coexistence of three magnetic phases in its magnetic structure. A fit of the dependences following four different models, each of which a combination of three functions of chosen type, to the M(T) experimental dependence has been made. ((orig.))

  14. Implementation of Cloud Computing into VoIP

    OpenAIRE

    Floriana GEREA

    2012-01-01

    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 solu...

  15. Implementation of Cloud Computing into VoIP

    Directory of Open Access Journals (Sweden)

    Floriana GEREA

    2012-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Sandra Merayo

    2010-06-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Sánchez O. M.

    2004-04-01

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

  18. Facile synthesis, phase transition, optical switching and oxidation resistance properties of belt-like VO2(A) and VO2(M) with a rectangular cross section

    International Nuclear Information System (INIS)

    Highlights: ? Belt-like VO2(A) with a rectangular cross section was synthesized. ? The formation mechanism of belt-like VO2(A) was proposed. ? Belt-like VO2(M) was prepared by the irreversible transformation of VO2(A). ? VO2(A) and VO2(M) can be used as the optical switching materials. ? VO2(A) and VO2(M) have good oxidation resistance below 400 °C in air. -- Abstract: Belt-like VO2(A) with a rectangular cross section (VA-RCS) was successfully synthesized using V2O5, H2C2O4·2H2O and H2O as the starting materials by a facile hydrothermal approach. Some synthetic parameters, such as, the reaction time, reaction temperature and concentration of H2C2O4·2H2O, were systematically investigated to control the fabrication of belt-like VA-RCS. The formation mechanism of belt-like VA-RCS was proposed. Subsequently, belt-like VO2(M) with a rectangular cross section (VM-RCS) was prepared by the irreversible transformation of VA-RCS at 700 °C for 2 h under the inert atmosphere. The phase transition temperature (Tc) of VA-RCS and VM-RCS was evaluated by DSC test. The optical switching properties of VA-RCS and VM-RCS were studied by the variable-temperature infrared spectra, and it was found that the as-obtained VA-RCS and VM-RCS could be used as the optical switching materials. Furthermore, the oxidation resistance properties of VA-RCS and VM-RCS were investigated by TGA, indicating that they have good thermal stability and oxidation resistance below 400 °C in air.

  19. Accuracy of peak VO2 assessments in career firefighters

    Directory of Open Access Journals (Sweden)

    Hong OiSaeng

    2011-09-01

    Full Text Available Abstract Background Sudden cardiac death is the leading cause of on-duty death in United States firefighters. Accurately assessing cardiopulmonary capacity is critical to preventing, or reducing, cardiovascular events in this population. Methods A total of 83 male firefighters performed Wellness-Fitness Initiative (WFI maximal exercise treadmill tests and direct peak VO2 assessments to volitional fatigue. Of the 83, 63 completed WFI sub-maximal exercise treadmill tests for comparison to directly measured peak VO2 and historical estimations. Results Maximal heart rates were overestimated by the traditional 220-age equation by about 5 beats per minute (p 2 was overestimated by the WFI maximal exercise treadmill and the historical WFI sub-maximal estimation by ~ 1MET and ~ 2 METs, respectively (p 2 when compared to directly measured peak VO2. Conclusion Accurate assessment of cardiopulmonary capacity is critical in determining appropriate duty assignments, and identification of potential cardiovascular problems, for firefighters. Estimation of cardiopulmonary fitness improves using the revised 2008 WFI sub-maximal equation.

  20. 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

    Directory of Open Access Journals (Sweden)

    Luis Villalobos

    2013-01-01

    Full Text Available 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, respectivamente. 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, respectiva- mente; 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.

  1. Biomasa acumulada e intercambio gaseoso en maíz proveniente de semilla de diferente tamaño bajo humedad favorable y restringida: (con 3 tablas)

    Scientific Electronic Library Online (English)

    José Alberto, López-Santillán; Sergio, Castro-Nava; Carlos, Trejo-López; Ma. Del Carmen, Mendoza-Castillo; Joaquín, Ortiz-Cereceres.

    2004-12-01

    Full Text Available Se evaluó la velocidad de germinación y el crecimiento de plántulas de maíz provenientes de semilla de dos diferentes tamaños para determinarlas diferencias en la producción de biomasa durante la etapa vegetativa y estimar los efectos de una condición diferente de disponibilidad de humedad sobre el [...] estatus fisiológico de la plántula. Una mayor cantidad de biomasa en el endospermo y en el embrión de las semillas permitió una mayor disponibilidad de reservas durante la etapa posterior a la germinación y anterior a la emergencia, dando como resultado un mayor vigor inicial en las plántulas evaluadas, y en consecuencia una mayor acumulación de biomasa, tanto radical como aérea, durante la etapa vegetativa. La presencia de una restricción de humedad durante la germinación y la etapa vegetativa de estas plantas provocó un decremento de 72.6% en la acumulación de biomasa en la parte aérea, tanto en plantas provenientes de semilla grande como chica, como consecuencia de una disminución de diversos procesos fisiológicos como son la conductancia estomática, transpiración y tasa fotosintética. Abstract in english The germination speed and seedling growth of maize seed of two different sizes was evaluated. To determine the differences in the biomass production during the vegetative stage from different seed size, considering the effects of humidity on seedling physiological status. A larger amount of biomass [...] in endosperm and embryo allowed greater availability of reserves during the later stage of the germination; previous to emergency resulting in a high seedling vigor and a most accumulation of as much radical biomass as aerial during the vegetative stage, the water restriction during the germination and the vegetative stage of these plants caused a decrement of 72,6% in the aerial biomass accumulation in big and small seed plants, due to a diminution from diverse physiological processes such as stomatic conductance, transpiration and photosynthetic rate.

  2. 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)

  3. Prior Knowledge of Trial Number Influences the Incidence of Plateau at VO2max

    OpenAIRE

    Gordon, Dan; Caddy, Oliver; Merzbach, Viviane; Gernigon, Marie; Baker, James; Scruton, Adrian; Keiller, Don; Barnes, Richard

    2015-01-01

    The purpose of this study was to assess the VO2max plateau response at VO2max during a series of pre-determined trials. METHODS: Ten male well-trained athletes (age, 23.0 ± 3.2; height, 183.3 ± 5.5 cm; mass 77.5 ± 11.1 Kg; VO2max 66.5 ± 5.0 ml.kg-1,min-1), but who were VO2max testing naïve and with prior-knowledge of trial number completed four incremental tests to volitional exhaustion, separated by ~72-h for the determination of VO2max and gas exchange threshold. Throughout all trials VO2ma...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-13

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

  5. Carbon quantum dots coated BiVO4 inverse opals for enhanced photoelectrochemical hydrogen generation

    Science.gov (United States)

    Nan, Feng; Kang, Zhenhui; Wang, Junling; Shen, Mingrong; Fang, Liang

    2015-04-01

    Carbon quantum dots (CQDs) coated BiVO4 inverse opal (io-BiVO4) structure that shows dramatic improvement of photoelectrochemical hydrogen generation has been fabricated using electrodeposition with a template. The io-BiVO4 maximizes photon trapping through slow light effect, while maintaining adequate surface area for effective redox reactions. CQDs are then incorporated to the io-BiVO4 to further improve the photoconversion efficiency. Due to the strong visible light absorption property of CQDs and enhanced separation of the photoexcited electrons, the CQDs coated io-BiVO4 exhibit a maximum photo-to-hydrogen conversion efficiency of 0.35%, which is 6 times higher than that of the pure BiVO4 thin films. This work is a good example of designing composite photoelectrode by combining quantum dots and photonic crystal.

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

    Directory of Open Access Journals (Sweden)

    Yusleydi Enamorado Horrutiner

    2011-01-01

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

  7. VoIP Server HW/SW Codesign for Multicore Computing

    OpenAIRE

    Iqbal, Arshad

    2012-01-01

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

  8. VoIP Technology: Investigation of QoS and Security Issues

    OpenAIRE

    Amor Lazzez

    2014-01-01

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

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

    Science.gov (United States)

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

    2006-01-01

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

  10. Peer-to-Peer VoIP Communications Using Anonymisation Overlay Networks

    OpenAIRE

    Zhang, Ge; Fischer-Hübner, Simone

    2010-01-01

    Nowadays, Voice over Internet Protocol (VoIP) which enables voice conversation remotely over packet switched networks gains much attentions for its low costs and flexible services. However, VoIP calling anonymity, particularly to withhold "who called whom", is difficult to achieve since VoIP infrastructures are usually deployed in an open networking environment (e.g., the Internet). Our work studies an anonymisation overlay network (AON) based solution to prevent surveillance from external at...

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

    OpenAIRE

    Arjona, Andres

    2009-01-01

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

  12. Processing Facilitation Strategies in OV and VO Languages: A Corpus Study

    OpenAIRE

    Luis Pastor; Itziar Laka

    2013-01-01

    The present corpus study aimed to examine whether Basque (OV) resorts more often than Spanish (VO) to certain grammatical operations, in order to minimize the number of arguments to be processed before the verb. Ueno & Polinsky (2009) argue that VO/OV languages use certain grammatical resources with different frequencies in order to facilitate real-time processing. They observe that both OV and VO languages in their sample (Japanese, Turkish and Spanish) have a similar frequency of use of su...

  13. Validity of 20-MST for predicting VO2max of adult Singaporean athletes.

    OpenAIRE

    Sproule, J; Kunalan, C; M. Mcneill; Wright, H

    1993-01-01

    This investigation compared the results of direct and indirect measurements of maximum oxygen uptake (VO2max) of an Asian population. Twenty subjects (16 male, 4 female), all of whom were physical education students, were assessed directly using laboratory treadmill running to determine VO2max. The indirect estimation of VO2max was obtained using a modified form of the Leger and Lambert 20-m multistage shuttle run test (20-MST). Heart rates were recorded throughout both tests. Pearson product...

  14. A regression equation for the estimation of VO2max in Nepalese male adults

    OpenAIRE

    Pinaki Chatterjee; Alok K. Banerjee; Paulomi Das; Parimal Debnath

    2010-01-01

    The purpose of the study was to validate the applicability of 20-meter multi stage shuttle run test in Nepalese male College students. 40 Nepalese students were recruited for the study. Direct estimation of cardiorespiratory endurance (VO2max) comprised treadmill exercise followed by expired gas analysis by scholander micro-gas analyzer whereas VO2max was indirectly predicted by the 20-meter multistage shuttle run test. The difference between the mean (SD) VO2max values of direct measurement ...

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

    OpenAIRE

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

    2014-01-01

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

  16. Thermochromic CeO 2-VO 2 bilayers: Role of ceria coating in optical switching properties

    Science.gov (United States)

    Saitzek, Sébastien; Guinneton, Frédéric; Sauques, Laurent; Aguir, Khalifa; Gavarri, Jean-Raymond

    2007-11-01

    Bilayers of thermochromic vanadium dioxide (VO2) and cerium dioxide (CeO2) were elaborated by RF sputtering. The VO2 phase was first deposited on an amorphous substrate. Then a ceria layer was deposited on the VO2 film with variable thicknesses (from 20 to 160 nm). These systems of CeO2-VO2 bilayers present interesting optoelectronic properties, with a thermochromic transition at 68 °C due to the insulator-metal transition of VO2 phase, active in the infrared wavelength range. The bilayers were then characterized by X-ray diffraction, atomic force microscopy and Fourier Transform Infrared (FTIR) spectroscopy. For infrared radiations having long wavelengths (10 ?m and above), the optical properties (reflectance, emissivity) of CeO2-VO2 bilayers are independent of ceria thickness up to 160 nm. For shorter wavelengths (5 ?m), the optical reflectance and emissivity of VO2 are strongly attenuated by ceria layer, and this attenuation increases with thickness. For a fixed temperature, the apparent temperature determined by a thermal camera depends on ceria thickness. This shows that ceria can be used to control the apparent surface temperature of VO2. In the case of thin ceria layers, we show that ceria insures a good chemical protection of VO2.

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

    OpenAIRE

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

    2013-01-01

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

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

    KAUST Repository

    Christopoulos, Stavros Richard G

    2014-12-07

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

  19. 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.)

  20. EPR study of VO2+ doped glycine zinc sulphate single crystal

    Science.gov (United States)

    Prabakaran, R.; Subramanian, P.

    2015-06-01

    Single crystals Of GZS:VO2+ were grown by slow evaporation of solvent at room temperature. The EPR study was carried out at room temperature. Single crystal rotations in each of the three mutually orthogonal planes indicate single site occupation of VO2+ in the lattice. g and A tensors were calculated from the recorded EPR spectra. The principal values of g and A indicates existence of rhombic symmetry around the VO2+ ion. From the direction cosines of the g and A tensors, the locations of VO2+ in the lattice have been identified as substitutional site.

  1. 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.

  2. Time limit at VO2max velocity in elite crawl swimmers

    OpenAIRE

    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

    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...

  3. nc-VO2/Al2O3 nanocomposite films prepared by dual target magnetron sputtering

    International Nuclear Information System (INIS)

    A dual target magnetron sputtering system was used to synthesize nanocomposite films with VO2 nanocrystals embedded in Al2O3 matrix. Glancing incidence X-ray diffraction and high-resolution transmission electron microscopy reveal the formation of VO2 nanocrystallites with monoclinic structure. X-ray photoemission analysis confirmed that oxide particles predominantly possess VO2 stoichiometry. Valence band spectra acquired below and above transition temperature demonstrate that embedded VO2 particles exhibit a first-order monoclinic-to-tetragonal phase transition, however the band shape in a metallic state exhibits feature that is not characteristic for bulk material

  4. 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)

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

    2007-12-01

    Full Text Available 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

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

  6. Forest biomass variation in Southernmost Brazil: the impact of Araucaria trees / Variación de la biomasa forestal en el sur de Brasil: impacto de los árboles de Araucaria

    Scientific Electronic Library Online (English)

    Milena Fermina, Rosenfield; Alexandre F., Souza.

    2014-03-01

    Full Text Available Una variedad de factores ambientales y bióticos determinan el crecimiento de la vegetación y afectan la acumulación de biomasa vegetal. Desde la temperatura hasta la composición de especies, en los ecosistemas forestales el almacenamiento de la biomasa aérea se ve influenciada por una serie de varia [...] bles, razón por la cual generalmente presenta una alta variabilidad espacial. De acuerdo a esto, el objetivo del estudio es analizar las variables que afectan la biomasa área (en Inglés, aboveground forest biomass - AGB) en los bosques húmedos subtropicales del sur de Brasil y analizar su distribución espacial. Para el estudio se utilizaron los datos de un inventario forestal realizado en el estado de Rio Grande del Sur, sur de Brasil. Se evaluaron bosques de hoja ancha (Broadleaf forests) y bosques mixtos de hoja ancha y coníferas (Mixed Coniferous-Broadleaf forests). Además, se tomaron muestras de 38 parcelas de 1 ha y para la estimación de la biomasa se incluyeron todos los árboles con DAP ?9.5cm. Los valores para la biomasa aérea se obtuvieron con ecuaciones alométricas publicadas. Las variables ambientales y bióticas (altitud, precipitación, temperatura, suelo, densidad de los troncos y diversidad de especies) se obtuvieron de la literatura o se han calculado a partir del conjunto de datos. Para el conjunto de datos, el AGB medio fue 195.2Mg/ha. Las estimaciones difieren entre los bosques de hoja ancha y los bosques mixtos de hoja ancha y coníferas: el AGB promedio fue menor en los bosques de hoja ancha (AGB BF=118.9Mg/ha) en comparación con los bosques mixtos (AGB MF=250.3Mg/ha). Hubo una alta variabilidad espacial y local en la base de datos, incluso dentro de los tipos de bosques. Esta condición es normal en los bosques tropicales y por lo general se atribuye a la presencia de grandes árboles. La regresión múltiple fue influenciada principalmente por la altitud y explicó 50.7% de la variación en AGB. La densidad, diversidad y materia orgánica también influyeron en la variación de biomasa. Los resultados mostraron una relación positiva entre la biomasa sobre el suelo y la altitud. Por lo tanto, los valores más altos de AGB se encuentran en altitudes mayores y se someten a temperaturas más bajas y un clima más húmedo. Parece que hay una importante contribución de las coníferas Araucaria angustifolia en las parcelas de bosques mixto, ya que tienen una biomasa significativamente mayor que las especies de angiospermas. En Brasil, esta especie en peligro de extinción es parte de un bosque de gran diversidad (Bosque de Araucaria) y tiene el potencial de almacenamiento de la biomasa. Los resultados del presente estudio muestran la variabilidad espacial y local de la biomasa aérea en los bosques subtropicales, destacan la importancia de estos ecosistemas en el almacenamiento global del carbono, y estimulan la mejora de futuras estimaciones de biomasa. Abstract in english A variety of environmental and biotic factors determine vegetation growth and affect plant biomass accumulation. From temperature to species composition, aboveground biomass storage in forest ecosystems is influenced by a number of variables and usually presents a high spatial variability. With this [...] focus, the aim of the study was to evaluate the variables affecting live aboveground forest biomass (AGB) in Subtropical Moist Forests of Southern Brazil, and to analyze the spatial distribution of biomass estimates. Data from a forest inventory performed in the State of Rio Grande do Sul, Southern Brazil, was used in the present study. Thirty-eight 1-ha plots were sampled and all trees with DBH ?9.5cm were included for biomass estimation. Values for aboveground biomass were obtained using published allometric equations. Environmental and biotic variables (elevation, rainfall, temperature, soils, stem density and species diversity) were obtained from the literature or calculated from the dataset. For the total dataset, mean AGB was 195.2Mg/ha. Estimates differed between Broadleaf and Mixed Co

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

    Directory of Open Access Journals (Sweden)

    Shu Wei-Chou

    2013-06-01

    Full Text Available One of the most relevant measures for climate change mitigation is the conservation and regeneration of forests in our countries. The amount of stored carbon in the forest biomass becomes a relevant variable for public policy. The present article analyses the association of some dasometric variables, easily obtained, with tree biomass with the purpose of indirectly estimating it, given that direct measurement of tree biomass is a complex and very expensive task. The general objective of this study was to analyze the pattern shown by dasometric variables, easily obtained, with tree biomass to estimate it by using data from two tropical forests in Costa Rica, with the purpose of analyzing its potential general application in tropical forests in the entire country. The bibliographic review helped to identify four possible models which estimate biomass in tropical forests. 907 trees were used with diameter at breast height (dbh greater than 10 cm in two tropical forests in Costa Rica (Corcovado National Park at the SW of the country, and Fila Carbón at the SE part, Caribbean slope, generating a biomass estimate as precise as possible. Dasometric variables (wood density, total height and dbh were used to analyze their relationship with biomass with the objective of finding a model that could predict it. The final model uses, as independent variables, dbh and density. Dbh has a high correlation with tree total height, which is very difficult to obtain in the field, therefore it was not used. The variable density is very important as it varies between trees having the same structure but of different species. To estimate the model, a segmented regression technique was used as well as weighted mean squares to solve for heteroscedasticity. The final model met all statistical assumptions for a linear model according to the residual and parametric analysis. The determination coefficient resulted in 0,992. As a conclusion, the study proposes a methodological approach to estimate forest biomass, which is very useful to support decision-making on carbon storage in tropical forests. Biomass determination in the field in future plots is going to help the calibration of this approach to estimate biomass stored in tropical forests.Una de las medidas más relevantes para la mitigación del cambio climático es la conservación y regeneración del bosque en nuestros países.  La cantidad de carbono que se almacena en la biomasa arbórea pasa a ser una medida relevante para la política pública. El presente trabajo analiza la asociación que tienen algunas variables dasométricas, fácilmente medibles, asociadas a la biomasa, con el propósito de estimarla indirectamente, dado que la medición directa de la biomasa arbórea es un trabajo complejo y tiene un costo muy elevado.  El objetivo general del estudio fue hacer un análisis del comportamiento de las variables dasométricas fácilmente medibles para predecir biomasa arbórea con datos de dos bosques tropicales de Costa Rica, con el propósito de analizar su posible aplicación generalizada en los bosques tropicales de todo el país. Mediante una revisión bibliográfica, se determinaron cuatro posibles modelos que estiman biomasa en bosques tropicales. Se evaluaron 907 árboles con diámetro a la altura de pecho (dap mayor a 10 cm en dos bosques tropicales de Costa Rica (Parque Nacional Corcovado en el suroeste y Fila Carbón en el sureste, vertiente del Caribe, generando una estimación de biomasa lo más precisa posible. Se realizó un análisis de las variables de los árboles (densidad específica de la madera, altura total y dap y su biomasa, con el fin de desarrollar el modelo que facilitara la predicción de esta. El modelo final utiliza como variables independientes el dap y la densidad.  Con el dap se da el hecho de que existe una alta correlación con la altura total, la cual es muy difícil de obtener en el campo, de modo que se decidió no utilizarla. La variable densidad es importante, ya que dos árboles con la misma estructura pero distinta densid

  8. VoIP Technology: Investigation of QoS and Security Issues

    Directory of Open Access Journals (Sweden)

    Amor Lazzez

    2014-06-01

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

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

    Directory of Open Access Journals (Sweden)

    David Irwin

    2012-09-01

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

  10. TAPAS, a VO archive at the IRAM 30-m telescope

    Science.gov (United States)

    Leon, Stephane; Espigares, Victor; Ruíz, José Enrique; Verdes-Montenegro, Lourdes; Mauersberger, Rainer; Brunswig, Walter; Kramer, Carsten; Santander-Vela, Juan de Dios; Wiesemeyer, Helmut

    2012-07-01

    Astronomical observatories are today generating increasingly large volumes of data. For an efficient use of them, databases have been built following the standards proposed by the International Virtual Observatory Alliance (IVOA), providing a common protocol to query them and make them interoperable. The IRAM 30-m radio telescope, located in Sierra Nevada (Granada, Spain) is a millimeter wavelength telescope with a constantly renewed, extensive choice of instruments, and capable of covering the frequency range between 80 and 370 GHz. It is continuously producing a large amount of data thanks to the more than 200 scientific projects observed each year. The TAPAS archive at the IRAM 30-m telescope is aimed to provide public access to the headers describing the observations performed with the telescope, according to a defined data policy, making as well the technical data available to the IRAM staff members. A special emphasis has been made to make it Virtual Observatory (VO) compliant, and to offer a VO compliant web interface allowing to make the information available to the scientific community. TAPAS is built using the Django Python framework on top of a relational MySQL database, and is fully integrated with the telescope control system. The TAPAS data model (DM) is based on the Radio Astronomical DAta Model for Single dish radio telescopes (RADAMS), to allow for easy integration into the VO infrastructure. A metadata modeling layer is used by the data-filler to allow an implementation free from assumptions about the control system and the underlying database. TAPAS and its public web interface ( http://tapas.iram.es ) provides a scalable system that can evolve with new instruments and observing modes. A meta description of the DM has been introduced in TAPAS in order to both avoid undesired coupling between the code and the DM and to provide a better management of the archive. A subset of the header data stored in TAPAS will be made available at the CDS.

  11. Analysis of VoIP Traffic with Multiple Packet Transfer

    Directory of Open Access Journals (Sweden)

    Tara Chand, Vishal Srivastava

    2012-06-01

    Full Text Available Voice over Internet Protocol (VoIP is a form of voice communication. Today Wireless LANs are providing a cost effective alternative for the voice communication. Initially the wireless access protocols are not suitable for the voice communication. Subsequently, new techniques are developed for the real time voice communication. In voice communication the delay is an important factor. In this paper a new technique is proposed for the voice over IEEE 802.11 WLANs. The proposed technique is compared with Modified ICF

  12. Content Delivery System for Optimal VoD Streaming

    OpenAIRE

    Gramatikov, Sasho; Jaureguizar Núñez, Fernando; Cabrera Quesada, Julian; García Santos, Narciso

    2011-01-01

    The demand of video contents has rapidly increased in the past years as a result of the wide deployment of IPTV and the variety of services offered by the network operators. One of the services that has especially become attractive to the customers is real-time video on demand (VoD) because it offers an immediate streaming of a large variety of video contents. The price that the operators have to pay for this convenience is the increased traffic in the networks, which are becoming more conges...

  13. Zircon to monazite phase transition in CeVO4

    OpenAIRE

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

    2011-01-01

    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 obser...

  14. Comprehensive picture of VO2 from band theory

    KAUST Repository

    Zhu, Zhiyong

    2012-08-28

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

  15. Caracterización de aerosoles por quema de biomasa en el sureste de México / Characterization of biomass burning aerosols over southeast Mexico

    Scientific Electronic Library Online (English)

    Virginia Edith, Cortés-Hernández; Javier, Aparicio.

    2014-02-01

    Full Text Available La caracterización de los aerosoles atmosféricos es de gran importancia en los procesos de transferencia radiativa en la atmósfera y el balance de radiación del sistema climático. En este trabajo se presentan algunas propiedades físicas que forman parte de la caracterización óptica y radiativa de lo [...] s aerosoles atmosféricos registrados en dos sitios de monitoreo pertenecientes a la red AERONET, ubicados al sureste de México, durante el periodo 2005-2007. La ubicación de los dos sitios de monitoreo correspondió a la región de mayor quema de biomasa por incendios forestales durante el año 2005. La caracterización de los aerosoles atmosféricos consideró cuatro casos de estudio: 1) 23 de abril de 2005, en Tenosique, Tabasco; 2) 27 de abril de 2005; 3) 8 de mayo de 2006, y 4) 24 de mayo de 2007, en Tuxtla Gutiérrez, Chiapas. Los resultados muestran altos valores del espesor óptico del aerosol (? > 1.4), altos valores del coeficiente de Ångström (? > 0.8), modos finos de acumulación del aerosol (r Abstract in english Characterization of aerosols is important for the atmospheric radiative process and the radiation budget of the climate system. This study presents some physical properties forming part of the optical and radiative characterization of atmospheric aerosols measured in two monitoring sites from the AE [...] RONET network located in Southeastern Mexico during 2005-2007. The location of both sites corresponded to the region of high biomass burning activity during 2005. Characterization of aerosols considered four study cases: 1) April 23, 2005 in Tenosique, Tabasco, 2) April 27, 2005, 3) May 8, 2006 and 4) May 24, 2007 in Tuxtla Gutierrez, Chiapas. Results show values of high atmospheric optical depth (? > 1.4), fine accumulation mode particles (r

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

    Scientific Electronic Library Online (English)

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

    2011-12-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Zvezdana Rajkovaca

    2005-12-01

    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.

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

    OpenAIRE

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

    2013-01-01

    Aim: The purpose of this study was to assess the indirect calculation of VO2max using ACSM’s equation for Bruce protocol in athletes of different sports and to compare with the directly measured; secondly to develop regression models predicting VO2 max in athletes.

  19. The VO-5 fan for the coal industry and for agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Raskin, I.A.; Ivanov, S.K.; Karminskiy, V.N.

    1984-01-01

    The characteristics, description and results of tests of the VO-5 fan are cited. It has a diameter of 5.00 meters and is designed for use on the surface of mines and for drying grain in grain storage facilities. Series production of the VO-5 began in 1982.

  20. Modelos de biomasa aérea y foliar en una plantación de pino de rápido crecimiento en Oaxaca / Above-ground and needle biomass models on a fast-growing pine plantation in Oaxaca

    Scientific Electronic Library Online (English)

    Gerardo, Rodríguez-Ortiz; Héctor M., De Los Santos-Posadas; Víctor A., González-Hernández; Arnulfo, Aldrete; Armando, Gómez-Guerrero; Aurelio M., Fierros-González.

    Full Text Available El vigor de un árbol se puede evaluar a partir del follaje, que si bien representa de 4% a 6% de la biomasa total del árbol, es el componente principal para los procesos fisiológicos. El objetivo de este estudio fue estimar la biomasa de acículas en ramas individuales y árbol completo, y ajustar mod [...] elos de partición de biomasa aérea en árboles plantados de Pinus patula Schl. et Cham. La biomasa de acículas por rama se estimó con un modelo lineal, que empleó área basal de rama viva, altura de rama y el seccionamiento de copa como variables independientes. La biomasa de los componentes aéreos se estimó con coeficientes de determinación de 0,86; 0,92 y 0,88; para madera con corteza, ramas y acículas, respectivamente. Para madera con corteza se utilizó el diámetro normal (DN) y altura de árbol (AT) en un modelo lineal; la biomasa de ramas y follaje con ecuaciones no lineales que se basaron en el diámetro de copa viva (DCV) y área de copa para ramas; y DCV y AT para la biomasa de follaje. La biomasa total aérea por árbol se estimó con un R² = 0,87; utilizando DN y AT. La biomasa a una edad de 14 años se distribuyó en 92,9%; 4,7% y 2,4% para madera, ramas y follaje, respectivamente. Abstract in english A forest tree health can be accurately assessed by evaluating foliage biomass; even when it represents only 4% to 6% of the total tree biomass, it is the main driver of every major physiological processes. This research was mainly focused on estimating accurately needle biomass at branch and tree le [...] vel on fast growing trees of Pinus patula Schl. et Cham. Needle biomass per branch was estimated with a linear model, which used live branch basal area, live branch height, and crown section like independent variables. Above ground components were estimated with determination coefficients of 0,86, 0,92 and 0,88 for wood with bark, branches and needles. For the wood with bark model, diameter at breast height (DBH) and total tree height (HT) were used in a linear structure; total branch biomass was fitted with a non-linear model, using live crown diameter (LCD) and crown area (CA) while total needle biomass used LCD and HT on a non-linear model. The aboveground total biomass per tree was estimated with R² = 0.87, using DBH and HT. At 14 years old, biomass partition was estimated to be 92,9%, 4,7% and 2,4% for wood with bark, branches and needles, respectively.

  1. 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)

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

    2014-12-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2014-06-01

    Single-crystalline vanadium dioxide (VO2) nanostructures have attracted an intense research interest recently because of their unique single-domain metal-insulator phase transition property. Synthesis of these nanostructures in the past was limited in density, alignment, or single-crystallinity. The assembly of VO2 nanowires (NWs) is desirable for a ``bottom-up'' approach to the engineering of intricate structures using nanoscale building blocks. Here, we report the successful synthesis of horizontally aligned VO2 NWs with a dense growth mode in the [1-100]quartz direction of a polished x-cut quartz surface using a simple vapor transport method. Our strategy of controlled growth of VO2 NWs promisingly paves the way for designing novel metal-insulator transition devices based on VO2 NWs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-28

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

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

    Science.gov (United States)

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

    2014-09-01

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

  5. Estimación de biomasa y carbono en dos especies arboreas en La Sierra Nevada, México / Estimation of biomass and carbon in two arboreal species in the Sierra Nevada, Mexico

    Scientific Electronic Library Online (English)

    Fernando, Carrillo Anzúres; Miguel, Acosta Mireles; Eulogio, Flores Ayala; Juana Eliud, Juárez Bravo; Eunice, Bonilla Padilla.

    2014-08-01

    Full Text Available Se generaron dos ecuaciones para determinar biomasa y carbono en Pinus montezumae y Alnus jorullensis H. B. K. ssp. jorullensis especies de importancia ecológica de los bosques de la Sierra Nevada en el Estado de México. Las ecuaciones que se determinaron son de la forma Y= bXk, donde Y es el conten [...] ido de biomasa o de carbono (kg) y X el diámetro normal (DN) en cm. Para estimar los valores b y k del modelo para cada especie, se utilizaron 15 árboles de Pinus montezumae y 16 de Alnus jorullensis ssp. jorullensis. En Pinus montezumae el mayor porcentaje de biomasa 77.07 % se estimó en el fuste incluido el tocón, mientras que en las ramas y el follaje presentó 8.45 y 9.01%, respectivamente, con la biomasa y el DN de los árboles se obtuvo el ajuste de los parámetros b y k del modelo propuesto (B= 0.013 DN3.0462) con una R²= 0.9909. Para el caso de Alnus jorullensis ssp. jorullensis de la misma forma el mayor porcentaje de biomasa 63.77% se estimó en el fuste incluido el tocón, mientras que en las ramas y el follaje presentó 20.99 y 11.46%, respectivamente; con la biomasa y el DN de los árboles se obtuvo el ajuste de los parámetros b y k del modelo propuesto (B= 0.0195 DN2.7519) con una R²= 0.9311. Después de analizar el contenido de carbono en las muestra de cada especie, se ajustaron las ecuaciones para Pinus montezumae C= 0.0065DN3.0484, con una R²= 0.9914, mientras que para Alnus jorullensis ssp. jorullensis C= 0.009DN2.7522con una R²= 0.9313. Abstract in english Two equations were generated for determining the biomass and carbon in Pinus montezumae and Alnus jorullensis HBK ssp. jorullensis of ecological important species of the forests of the Sierra Nevada in the State of Mexico. The equations were determined are of the form Y= bXk, where Y is the biomass [...] content or carbon (kg) and X normal diameter (DN) in cm. For estimating the model and k values for each species, Pinus montezumae 15 trees and 16 Alnus jorullensis ssp. jorullensis were used. In Pinus montezumae the highest percentage of biomass was estimated at 77.07% including the stem stump, while the branches and foliage showed 8.45 and 9.01%, respectively, biomass and DN trees the adjustment is obtained by k parameters of the proposed model (B= 0.013 DN3.0462) with R²= 0.9909. For the case of Alnus jorullensis ssp. jorullensis the same as the highest percentage of biomass was estimated at 63.77% including the stem stump, while the branches and foliage showed 20.99 and 11.46%, respectively; with biomass and tree DN setting the parameters of the proposed model by k (B= 0.0195 DN2.7519) with R²= 0.9311 was obtained. After analyzing the carbon content in the sample of each species, the equations for Pinus montezumae C= 0.0065DN3.0484, with R²= 0.9914, while for Alnus jorullensis ssp jorullensis was adjusted. C= 0.009DN2.7522 con an R²= 0.9313.

  6. Individual plant and population biomass of dominant shrubs in Patagonian grazed fields / Biomasa individual y poblacional de arbustos dominantes en estepas patagónicas pastoreadas

    Scientific Electronic Library Online (English)

    Gastón R, Oñatibia; Martín R, Aguiar; Pablo A, Cipriotti; Fernando, Troiano.

    2010-12-01

    Full Text Available La estimación de la biomasa aérea de la vegetación es clave para llevar a cabo estudios de Ecología de Poblaciones, de Comunidades y de Ecosistemas. En sistemas dominados o codominados por leñosas, esta estimación es dificultosa, y es importante contar con métodos rápidos y no destructivos. En este [...] estudio describimos cómo se distribuye la biomasa aérea en distintos componentes (i.e., leño, hojas) y cómo cambia con el tamaño de arbusto para las tres especies dominantes de arbustos del Distrito Occidental de la estepa Patagónica. Además, describimos la estructura poblacional de tamaños de las tres especies en campos pastoreados y estimamos su contribución a la abundancia y la biomasa total a través de un método no destructivo. Desarrollamos ecuaciones alométricas para estimar la biomasa de los componentes aéreos de los individuos de arbustos a partir de descriptores estructurales (i.e., diámetros y altura de la copa). La variable que mejor predijo la biomasa aérea en las tres especies de arbustos fue la suma de la altura y el diámetro promedio (entre el diámetro mayor y el perpendicular) de la copa. Los modelos alométricos explicaron para cada especie más de 83% de la variabilidad de la biomasa aérea individual. En el nivel de individuo, las especies tuvieron distinta proporción de leño, hojas y distinto peso específico del leño. El aumento del tamaño individual de los arbustos fue acompañado por cambios en las proporciones de hojas/leño y en algunos casos por el porcentaje de copa muerta. En el nivel de población, las tres especies difirieron en la distribución de tamaños en pastizales pastoreados. La perspectiva poblacional utilizada para el desarrollo de los modelos alométricos es clave para estudiar los procesos demográficos que explican las respuestas de las comunidades y los ecosistemas áridos a los principales cambios ambientales y de uso. Abstract in english Estimating aboveground biomass of vegetation is essential for population, community and ecosystem studies. In systems dominated or co-dominated by woody species, biomass estimation is difficult, and rapid and non-destructive methods are needed. In this study, we describe biomass distribution in diff [...] erent components (i.e., wood, leaves) and how this changes with shrub size for the three dominant species of shrubs in the Occidental District of the Patagonian steppe. We also describe the population size structure of the three species in grazed fields and estimate their contribution to total abundance and biomass through a non-destructive method. We developed allometric equations to estimate aboveground biomass components of individual shrubs from structural descriptors (i.e., diameter and height of the crown), sampling individual plants of different sizes. The variable that best predicted biomass of the three species was the sum of the height and the average diameter of the crown (calculated with the largest diameter and its perpendicular). Allometric models for each species explained more than 83% of the variability of individual aboveground biomass. At the individual level, species had different proportions of wood, leaves and specific wood weight. Increasing shrub size was accompanied by changes in the proportion of leaves to wood, and in some cases, the percentage of dead crown. At the population level, the three species differed in size distribution in moderately grazed fields. Development of allometric models from a population perspective is important to study demographic processes that drive community and ecosystem responses to environmental and land-use changes.

  7. Estimación de biomasa aérea en plantaciones de Cedrela odorata L. y Swietenia macrophylla King / Aerial biomass estimation in Cedrela odorata L. and Swietenia macrophylla King plantations

    Scientific Electronic Library Online (English)

    Agustín, Rueda Sánchez; Agustín, Gallegos Rodríguez; Diego, González Eguiarte; J. Ariel, Ruiz Corral; Juan de Dios, Benavides Solorio; Eduardo, López Alcocer; Miguel, Acosta Mireles.

    2014-10-01

    Full Text Available Se evaluaron las capacidades de producción de biomasa y de captura de carbono en plantaciones de Cedrela odorata y Swietenia macrophylla con 12 años en el estado de Jalisco. En campo fueron seleccionados y derribados 15 árboles de cada especie para determinar la biomasa y el carbono en el estrato aé [...] reo; se tomaron muestras del fuste, de las ramas (brazuelo y leña) y del follaje de cada individuo para conocer su peso fresco; en el laboratorio se secaron para obtener el peso seco y con estos datos se calculó la biomasa total de cada ejemplar a partir de la relación peso seco: peso fresco. Para realizar las estimaciones se ajustaron ecuaciones de regresión tipo polinomial y potencial, el diámetro normal y la altura fueron las variables independientes. Al peso seco de cada componente del árbol se le aplicó un índice de captura de carbono de 0.4269 y con ello se obtuvo el potencial de captura de carbono atmosférico. Para C. odorata el total de biomasa promedio por espécimen fue de 34 kg, en la que se distribuye 75 % de la biomasa en el fuste, 11 % en el brazuelo, 9 % en ramas (leña) y 5 % en el follaje. Para S. macrophylla el total de biomasa promedio por espécimen fue de 26 kg, del cual 47 % se distribuye en el fuste, 19 % en el brazuelo, 23 % en ramas y 10 % en el follaje. Abstract in english This study was conducted with the aim of assessing the ability of biomass production and carbon sequestration by plantations of Cedrela odorata and Swietenia macrophylla in a plantation established 12 years ago in the state of Jalisco, Mexico. At Costa de Jalisco Experimental Site of the Instituto N [...] acional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP) and 15 trees of each species were selected and felled and the biomass and carbon in the aerial stratum were determined. Samples were taken from the stem, branches (twigs and firewood) and foliage of each of the selected trees and fresh weight was determined in the field from both species; the samples were dried in a laboratory to obtain the dry weight and estimate the total biomass of each tree using the ratio dry weight: fresh weight of samples. To estimate the biomass and carbon and polynomial regression equations were fit; the independent variables were normal diameter and tree height. To the dry weight of each tree component was applied a carbon sequestration index of 0.4269, thereby determining the potential for atmospheric carbon sequestration. For C. odorata, the total average biomass per tree was 34 kg, 75 % of which belongs to the biomass in the stem, 11 % in the trunk, 9 % in branches (wood) and 5 % in foliage. For S. macrophylla, the total average biomass per tree was 26 kg, which are distributed as 47 % in the stem, 19 % in the trunk, 23 % in branches and 10 % in the foliage.

  8. AstroStat-A VO tool for statistical analysis

    Science.gov (United States)

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

    2015-06-01

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

  9. AstroStat - A VO Tool for Statistical Analysis

    CERN Document Server

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-01

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

  11. Prepaid and Postpaid VoIP Service Enhancements and Hybrid Network Performance Measurement

    Directory of Open Access Journals (Sweden)

    Mohd Nazri Ismail

    2006-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-28

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

  13. 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)

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

    2008-09-01

    Full Text Available 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.

  14. Carbono almacenado en la biomasa aérea de plantaciones de araucaria (Araucaria angustifolia -Bert.- O. Ktze) / Aboveground carbon stocks in plantations of araucariaç (Araucaria angustifolia -Bert.- O. Ktze)

    Scientific Electronic Library Online (English)

    José D, Vega; Rodolfo, Martiarena.

    2010-06-01

    Full Text Available En este trabajo se estima el carbono aéreo almacenado en plantaciones de Araucaria angustifolia (Bert.) O. Ktze de diferentes edades, localizadas en el norte de la provincia de Misiones. Se determina la biomasa aérea por muestreo destructivo de árboles de 1, 2, 3, 6, 20, 30 y 40 años de edad, se aju [...] stan ecuaciones para estimar el peso seco de los restantes árboles de la parcela y se calcula la biomasa y el carbono en la totalidad de la plantación de cada una de las edades. El carbono almacenado en la biomasa aérea es de 0,04; 0,31; 1,3; 21,9; 56,2; 60,5 y 92,2 Mg.ha-1 para las edades de 1, 2, 3, 6, 20, 30 y 40 años respectivamente. Abstract in english This work estimated the aboveground carbon stock in plantations of Araucaria angustifolia -Bert.- O. Ktze of different ages, located in the north of the province of Misiones. The aboveground biomass was determined by destructive sampling of trees of 1, 2, 3, 6, 20, 30 and 40 years of age, equations [...] were adjusted to estimate the dry weight of the remaining trees of the plot and biomass and carbon were calculated in the whole plantation of exemplars of all the ages mentioned. The carbon of the total aboveground biomass is 0,04; 0,31; 1,3; 21,9; 56,2; 60,5 and 92,2 Mg.ha-1 for tree ages 1, 2, 3, 6, 20, 30 and 40, respectively.

  15. 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)

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

    1999-12-01

    Full Text Available 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.

  16. 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)

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

    2009-08-01

    Full Text Available 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.

  17. Effects of training on muscle O2 transport at VO2max

    Science.gov (United States)

    Roca, J.; Agusti, A. G.; Alonso, A.; Poole, D. C.; Viegas, C.; Barbera, J. A.; Rodriguez-Roisin, R.; Ferrer, A.; Wagner, P. D.

    1992-01-01

    To quantify the relative contributions of convective and peripheral diffusive components of O2 transport to the increase in leg O2 uptake (VO2leg) at maximum O2 uptake (VO2max) after 9 wk of endurance training, 12 sedentary subjects (age 21.8 +/- 3.4 yr, VO2max 36.9 +/- 5.9 ml.min-1.kg-1) were studied. VO2max, leg blood flow (Qleg), and arterial and femoral venous PO2, and thus VO2leg, were measured while the subjects breathed room air, 15% O2, and 12% O2. The sequence of the three inspirates was balanced. After training, VO2max and VO2leg increased at each inspired O2 concentration [FIO2; mean over the 3 FIO2 values 25.2 +/- 17.8 and 36.5 +/- 33% (SD), respectively]. Before training, VO2leg and mean capillary PO2 were linearly related through the origin during hypoxia but not during room air breathing, suggesting that, at 21% O2, VO2max was not limited by O2 supply. After training, VO2leg and mean capillary PO2 at each FIO2 fell along a straight line with zero intercept, just as in athletes (Roca et al. J. Appl. Physiol. 67: 291-299, 1989). Calculated muscle O2 diffusing capacity (DO2) rose 34% while Qleg increased 19%. The relatively greater rise in DO2 increased the DO2/Qleg, which led to 9.9% greater O2 extraction. By numerical analysis, the increase in Qleg alone (constant DO2) would have raised VO2leg by 35 ml/min (mean), but that of DO2 (constant Qleg) would have increased VO2leg by 85 ml/min, more than twice as much. The sum of these individual effects (120 ml/min) was less (P = 0.013) than the observed rise of 164 ml/min (mean). This synergism (explained by the increase in DO2/Qleg) seems to be an important contribution to increases in VO2max with training.

  18. 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

    Directory of Open Access Journals (Sweden)

    Eduardo P. Pérez

    2005-11-01

    Full Text Available 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 variaciones 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 capturaA 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 abundance (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

  19. 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)

    Eduardo P., Pérez.

    2005-11-01

    Full Text Available 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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Science.gov (United States)

    Yu, Jianqiang; Zhang, Yan; Kudo, Akihiko

    2009-02-01

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

  2. Electrochemical properties of VO-flyash composite for lithium polymer battery

    Science.gov (United States)

    Kim, Jong-Uk; Gu, Hal-Bon

    A VO-flyash composite electrode for a lithium/polymer battery (LPB) was developed. We investigated XRD diffraction and electrochemical properties of vanadium oxide (VO)-flyash composite with polyvinylidene (PVDF)/polyacrylonitrile (PAN)-based polymer electrolyte as a function of mixing ratio. The discharge capacity of VO-flyash with 50 wt.% V 2O 5 in PVDF-PAN-PC 5EC 5iClO 4 electrolyte was 150 and 128 mAh/g at 1 and 10 cycles, respectively. The discharge capacity of VO-flyash with 85 wt.% V 2O 5 was 195 mAh/g at 10 cycles. The capacity retention of VO-flyash anode with 3 wt.% V 2O 5 was higher than that of VO-flyash cathode with 85 wt.% V 2O 5. The VO-flyash with 3 wt.% V 2O 5 composite anode in PVDF/PAN-based electrolyte shows good capacity with cycling.

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

    International Nuclear Information System (INIS)

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

  4. STRU?NO VO?ENJE: PODRU?JE RADA PROFESIONALNIH SUPERVIZORA?

    Directory of Open Access Journals (Sweden)

    Louis van Kessel

    2007-01-01

    Full Text Available Stru?no vo?enje je podru?je koje se vrlo dinami?no razvija. Oblici njegove pojavnosti mnogo su raznolikiji od aktivnosti koje se provode u okviru profesionalne supervizije iako ona ima odre?ena obilježja »stru?nog vo?enja«. Premda se podrijetlo i razvoj stru?nog vo?enja i supervizije razlikuju, ti su koncepti i njihova primjena me?usobno povezani. Profesionalni supervizori moraju imati jasnu sliku o podru?ju stru?nog vo?enja kako bi mogli redefinirati svoju poziciju u okviru današnje supervizije. Zbog toga moraju prou?avati razvoj stru?nog vo?enja. U ?lanku je prikazano kako se pojam stru?nog vo?enja pojavio u anglosaksonskom govornom podru?ju. ?lanak može poslužiti prakti?arima kao informativni vodi? i kao temelj za daljnja prou?avanja radi usporedbe stru?nog vo?enja i profesionalne supervizije te da bi se moglo to?nije odrediti po ?emu su te dvije aktivnosti razli?ite i sli?ne.

  5. Effects of erythrocyte infusion on VO2max at high altitude

    DEFF Research Database (Denmark)

    Young, Jette Feveile; Sawka, M N

    1996-01-01

    This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P <0.01) arterial hematocrit, hemoglobin concentration, and arterial O2 content in the erythrocyte-infused subjects. By HA9, there were no longer any differences in hematocrit, hemoglobin concentration, or arterial O2 content between groups. No change in VO2max occurred between HA1 and HA9 for either group. Thus, despite increasing arterial O2-carrying capacity, autologous erythrocyte infusion did not ameliorate the decrement in VO2max at 4,300-m altitude.

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

    Science.gov (United States)

    Molinaro, Marco; Knapic, Cristina; Smareglia, Riccardo

    2012-09-01

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

  7. 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 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

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

    Directory of Open Access Journals (Sweden)

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

    2012-10-01

    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%.

  9. A structured approach to VO reconfigurations through Policies

    Directory of Open Access Journals (Sweden)

    Stephan Reiff-Marganiec

    2012-04-01

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

  10. A structured approach to VO reconfigurations through Policies

    CERN Document Server

    Reiff-Marganiec, Stephan

    2012-01-01

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

  11. Spin polarized HSE hybrid functional calculations of VO2

    International Nuclear Information System (INIS)

    We study the rutile (R) and monoclinic (M1) phases of the prototypical compound VO2 by first principles calculations based on density functional theory, employing the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional. Our results show that the HSE lowest-energy solutions for both the low-temperature M1 phase and the high-temperature R phase, which are obtained upon inclusion of spin polarization, are at odds with experimental observations. For the M1 phase the groundstate is (but should not be) magnetic, while the groundstate of the R phase, which is also spin-polarized, is not (but should be) metallic. The energy difference between the low-temperature and high-temperature phases is also in strong discrepancy with the experimental latent heat.

  12. Zircon to monazite phase transition in CeVO4

    CERN Document Server

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

    2011-01-01

    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.

  13. Performability Aspects of the Atlas Vo; Using Lmbench Suite

    CERN Document Server

    Georgatos, Fotis; Kouretis, John

    2008-01-01

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

  14. Active terahertz nanoantennas based on VO2 phase transition.

    Science.gov (United States)

    Seo, Minah; Kyoung, Jisoo; Park, Hyeongryeol; Koo, Sukmo; Kim, Hyun-sun; Bernien, Hannes; Kim, Bong Jun; Choe, Jong Ho; Ahn, Yeong Hwan; Kim, Hyun-Tak; Park, Namkyoo; Park, Q-Han; Ahn, Kwangjun; Kim, Dai-sik

    2010-06-01

    Unusual performances of metamaterials such as negative index of refraction, memory effect, and cloaking originate from the resonance features of the metallic composite atom(1-6). Indeed, control of metamaterial properties by changing dielectric environments of thin films below the metallic resonators has been demonstrated(7-11). However, the dynamic control ranges are still limited to less than a factor of 10,(7-11) with the applicable bandwidth defined by the sharp resonance features. Here, we present ultra-broad-band metamaterial thin film with colossal dynamic control range, fulfilling present day research demands. Hybridized with thin VO(2) (vanadium dioxide) (12-18) films, nanoresonator supercell arrays designed for one decade of spectral width in terahertz frequency region show an unprecedented extinction ratio of over 10000 when the underlying thin film experiences a phase transition. Our nanoresonator approach realizes the full potential of the thin film technology for long wavelength applications. PMID:20469898

  15. Orbital-assisted metal-insulator transition in VO$_{2}$

    CERN Document Server

    Haverkort, M W; Tanaka, A; Reichelt, W; Streltsov, S V; Korotin, M A; Anisimov, V I; Hsieh, H H; Lin, H J; Chen, C T; Khomskii, D I; Tjeng, L H

    2005-01-01

    We found direct experimental evidence for an orbital switching in the V 3d states across the metal-insulator transition in VO$_{2}$. We have used soft-x-ray absorption spectroscopy at the V $L_{2,3}$ edges as a sensitive local probe, and have determined quantitatively the orbital polarizations. These results strongly suggest that, in going from the metallic to the insulating state, the orbital occupation changes in a manner that charge fluctuations and effective band widths are reduced, that the system becomes more 1-dimensional and more susceptible to a Peierls-like transition, and that the required massive orbital switching can only be made if the system is close to a Mott insulating regime.

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

    Directory of Open Access Journals (Sweden)

    Jesús Adolfo Anaya Acevedo

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Miriam Rosero G

    2013-04-01

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

  18. Evaluación agronómica y nutricional del pasto Ryegrass perenne tetraploide (Lolium perenne producido en lecherías de las zonas altas de Costa Rica. I. Producción de biomasa y fenología

    Directory of Open Access Journals (Sweden)

    Luis Villalobos

    2010-01-01

    3090 msnm, provincia de Cartago. La disponibilidad de materia seca pre y pos-pastoreo, el aprovechamiento por hectárea y su porcentaje de utilización promedio para todas las fincas fueron 4110, 2276 y 1833 kg.ha-1 por corte y 44,82%, respectivamente. La edad fenológica y la relación hoja: tallo promedio de las pasturas de ryegrass perenne fueron 2,84 hojas verdes por rebrote, 56:44. Asimismo, la composición promedio de la pradera fue 76,09% ryegrass, 13,76% otras gramíneas (principalmente pasto kikuyo, 6,02% trébol, 1,25% malezas y 2,88% material senescente, respectivamente. La mayor producción de biomasa durante marzo y abril puede conservarse para utilizarse durante las épocas críticas de disponibilidad de forraje o cuando por razones climatológicas se reduce el número de horas efectivas de pastoreo. La evaluación de la edad fenológica en que se pastorea el pasto ryegrass perenne, indica que las fincas en la zona de estudio utilizan esta gramínea en un estado en el que sus reservas de carbohidratos se han recuperado, lo que permite obtener una producción de biomasa y valor nutricional adecuados para satisfacer las necesidades del ganado lechero de la zona.

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

    Directory of Open Access Journals (Sweden)

    Fausto Alexander Gamboa

    2012-05-01

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

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

    OpenAIRE

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

    2006-01-01

    Voice over Internet Protocol (VoIP) is becoming a reality in many organizations. The potential for mobility in voice over wi-fi networks will derive demand for the technology. Wireless VoIP is poised to rival VoIP as an alternative telephony tool. Internet has been used to transport data in the form of packet. In the past, Internet did not support any kind of sophisticated quality of service (QoS) mechanism. Although the type of service (TOS) field in the Internet protocol (IP) header has be...

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

    OpenAIRE

    Kashif Nisar; Abas Md Said,; Halabi Hasbullah

    2011-01-01

    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...

  2. Surface versus bulk characterization of the electronic inhomogeneity in a VO_{2} film

    OpenAIRE

    Chang, Y. J.; Yang, J.S.; Kim, Y. S.; Kim, D. H.; Noh, T. W.; Kim, D.-W.; Oh, E.; Kahng, B.; Chung, J. -S.

    2007-01-01

    We investigated the inhomogeneous electronic properties at the surface and interior of VO_{2} thin films that exhibit a strong first-order metal-insulator transition (MIT). Using the crystal structural change that accompanies a VO_{2} MIT, we used bulk-sensitive X-ray diffraction (XRD) measurements to estimate the fraction of metallic volume p^{XRD} in our VO_{2} film. The temperature dependence of the p$^{XRD}$ was very closely correlated with the dc conductivity near the M...

  3. Study on the QoE for VoIP Networks

    OpenAIRE

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

    2014-01-01

    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...

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

    OpenAIRE

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

    2013-01-01

    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...

  5. Physical origins of ON-OFF switching in ReRAM via VO based conducting channels

    Science.gov (United States)

    Kamiya, Katsumasa; Yang, Moon Young; Park, Seong-Geon; Magyari-Köpe, Blanka; Nishi, Yoshio; Niwa, Masaaki; Shiraishi, Kenji

    2013-12-01

    We study the ON-OFF switching mechanism of ReRAM via oxygen vacancy (VO) based conducting channels using first-principles calculations. We find cohesion-dispersion transition of VO upon carrier injection and removal is a strong driving force in the ON-OFF switching in binary-oxide-based ReRAMs. The physical origins of the transition is the formation of bonding-like hybridized orbitals of VO defect levels, whose occupation can be controlled by changing system Fermi level by applying a voltage.

  6. VO2max Trainability and High Intensity Interval Training in Humans: A Meta-Analysis

    OpenAIRE

    Bacon, Andrew P.; Carter, Rickey E; Ogle, Eric A.; Joyner, Michael J.

    2013-01-01

    Endurance exercise training studies frequently show modest changes in VO2max with training and very limited responses in some subjects. By contrast, studies using interval training (IT) or combined IT and continuous training (CT) have reported mean increases in VO2max of up to ?1.0 L · min?1. This raises questions about the role of exercise intensity and the trainability of VO2max. To address this topic we analyzed IT and IT/CT studies published in English from 1965–2012. Inclusion criteria w...

  7. Predictability of VO2 max from submaximal cycle ergometer and bench stepping tests.

    OpenAIRE

    Fitchett, M A

    1985-01-01

    The predictability of the maximal oxygen uptake (VO2 max) was studied using progressive and steady state protocols for cycle ergometry and bench stepping. The subjects were 12 healthy men, 23-58 years old. Prediction of VO2 max was made by extrapolation of the heart rate and O2 uptake at several sub-maximal work-loads using the least squares regression technique. The four sub-maximal procedures underestimated the measured VO2 max by between 0.13-0.55 l.min-1. The differences between the measu...

  8. 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)

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

    2014-09-01

    Full Text Available 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.

  9. Vplyv herbicídu Gesagard a fungicídu Fundazol na spolo?enstvo streptomycét vo vysokohorskej pôde.

    Czech Academy of Sciences Publication Activity Database

    Selešiová, Z.; Javoreková, S.; Krišt?fek, Václav; Chro?áková, Alica

    2010-01-01

    Ro?. 9, ?. 1 (2010), s. 13-19. ISSN 1336-1120 R&D Projects: GA MŠk LC06066 Grant ostatní: SAV(SK) VEGA 1/0404/09; SAV(SK) KEGA 3/6228/08 Institutional research plan: CEZ:AV0Z60660521 Keywords : pesticides * streptomycetes * grassland Subject RIV: EH - Ecology, Behaviour

  10. Podnikový dizajn vo verejnej správe na príklade švaj?iarskeho kantónu Luzern

    OpenAIRE

    Misun, Juraj; Hudakova, Ivana

    2011-01-01

    Corporate Design is the most visible Instrument of the Corporate Identity. Besides it Corporate Identity affects the Corporate Image also with the Corporate Communication and with the Corporate Behavior. Despite of its Name, delimit it to Usage in the Commerce Sphere, the Corporate Design is used in advanced Countries also by the Government Institutions, and also by the third Sector. A good Example is the Swiss Canton Lucerne.

  11. Determinants of peak VO2 in heart transplant recipients / Determinantes do pico de VO2 em transplantados cardíacos

    Scientific Electronic Library Online (English)

    Vitor Oliveira, Carvalho; Guilherme Veiga, Guimarães; Marcelo Luiz, Campos-Vieira; Aparecida Maria, Catai; Vagner, Oliveira-Carvalho; Silvia Moreira, Ayub-Ferreira; Edimar Alcides, Bocchi.

    2015-02-01

    Full Text Available Objetivo: Estabelecer os determinantes do VO2 pico em transplantados de coração. Métodos: Avaliação do paciente foi realizada em dois dias consecutivos. No primeiro dia, os pacientes realizaram a avaliação da variabilidade da frequência cardíaca seguida de um teste de esforço cardiopulmonar. No seg [...] undo dia, os pacientes realizaram ecocardiografia de repouso. Os transplantados foram elegíveis se estivessem em uma condição estável e sem qualquer evidência de rejeição diagnosticada por biópsia endomiocárdica. Pacientes com marca-passo, limitações funcionais não cardiovasculares, tais como osteoartrite e doença pulmonar obstrutiva crônica foram excluídos deste estudo. Resultados: Sessenta pacientes (68% do sexo masculino, 48 anos e 64 meses após o transplante cardíaco) foram avaliados. A análise multivariada selecionou as seguintes variáveis: sexo (P=0,001), idade (P=0,049), Índice de Massa Corporal (P=0,005), frequência cardíaca de reserva (P Abstract in english Objective: To establish the determinants of the peak VO2 in heart transplant recipients. Methods: Patient's assessment was performed in two consecutive days. In the first day, patients performed the heart rate variability assessment followed by a cardiopulmonary exercise test. In the second day, pa [...] tients performed a resting echocardiography. Heart transplant recipients were eligible if they were in a stable condition and without any evidence of tissue rejection diagnosed by endomyocardial biopsy. Patients with pacemaker, noncardiovascular functional limitations such as osteoarthritis and chronic obstructive pulmonary disease were excluded from this study. Results: Sixty patients (68% male, 48 years and 64 months following heart transplantation) were assessed. Multivariate analysis selected the following variables: receptor's gender (P=0.001), receptor age (P=0.049), receptor Body Mass Index (P=0.005), heart rate reserve (P

  12. Electrochemical behavior of [(Mn(Bpy))(VO3)2]?(H2O)1.24 and [(Mn(Bpy)0.5)(VO3)2]?(H2O)0.62 inorganic–organic Brannerites in lithium and sodium cells

    International Nuclear Information System (INIS)

    The performance of MnV2O6 (MnV) and its [(Mn(Bpy))(VO3)2]?(H2O)1.16 (MnBpy) and [(Mn(Bpy)0.5)(VO3)2]?(H2O)0.62(MnBpy0.5) hybrid derivative compounds was investigated against sodium and lithium counter electrodes. For MnV2O6 stable capacities of 850 mAh/g were achieved in lithium cells, the best value reported so far. The whole capacity is ascribed to a conversion reaction in which the amorphization of the compounds takes place. No significant differences in the capacities for the inorganic compound and the hybrid ones were observed. Interestingly, the potential hysteresis decreases in the hybrid compounds. The difference between Li and Na cell capacity most probably comes from the difference of standard potential of the two redox couples Li+/Li and Na+/Na of about ca. 0.3 V leading to an incomplete conversion reaction and thus lowers capacity in the case of Na cells. The Raman and IR ex-situ experiments after cycling indicate that the bipyridine organic ligands are completely decomposed during the electrochemical testing. The IR studies in MnV inorganic and MnBpy and MnBpy0.5 hybrid electrodes after the electrochemical cycling, suggest that the SEI formation and bipyridine degradation give rise to different aliphatic compounds. - Graphical abstract: The electrochemical performance of [(Mn(Bpy))(VO3)2]?(H2O)1.16 and [(Mn(Bpy)0.5)(VO3)2]?(H2O)0.62 against sodium and lithium counter electrodes give rise to the structural collapse of the initial compounds. The IR and Raman studies show that the Bpy organic ligand is completely decomposed during the during the electrochemical testing. However, after the amorphization stable capacities as high as 850 mAh/g for lithium cells were achieved. - Highlights: • We test the lithium and sodium insertion in hybrid brannerites. • Capacities as large as 850 mAh/g were obtained for the Li cells. • The capacity and good cycling is ascribed to a conversion reaction of the electrodes. • The Bpy molecule of the hybrid compounds is degraded during the first reduction. • The decomposition products of the Bpy ligand reduce the potential hysteresis

  13. Electrochemical behavior of [(Mn(Bpy))(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 1.24} and [(Mn(Bpy){sub 0.5})(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 0.62} inorganic–organic Brannerites in lithium and sodium cells

    Energy Technology Data Exchange (ETDEWEB)

    Fernández de Luis, Roberto, E-mail: roberto.fernandez@ehu.es [Departamento de Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain); Ponrouch, Alexandre, E-mail: aponrouch@icmab.es [Institut de Ciència de Materials de Barcelona (CSIC) Campus UAB, E-08193, Bellaterra, Catalonia (Spain); Rosa Palacín, M., E-mail: rosa.palacin@icmab.es [Institut de Ciència de Materials de Barcelona (CSIC) Campus UAB, E-08193, Bellaterra, Catalonia (Spain); Karmele Urtiaga, M., E-mail: karmele.urtiaga@ehu.es [Departamento de Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain); Arriortua, María I., E-mail: maribel.arriortua@ehu.es [Departamento de Mineralogía y Petrología, Facultad de Ciencia y Tecnología, Universidad del País Vasco, UPV/EHU, Apdo. 644, E-48080 Bilbao (Spain)

    2014-04-01

    The performance of MnV{sub 2}O{sub 6} (MnV) and its [(Mn(Bpy))(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 1.16} (MnBpy) and [(Mn(Bpy){sub 0.5})(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 0.62}(MnBpy0.5) hybrid derivative compounds was investigated against sodium and lithium counter electrodes. For MnV{sub 2}O{sub 6} stable capacities of 850 mAh/g were achieved in lithium cells, the best value reported so far. The whole capacity is ascribed to a conversion reaction in which the amorphization of the compounds takes place. No significant differences in the capacities for the inorganic compound and the hybrid ones were observed. Interestingly, the potential hysteresis decreases in the hybrid compounds. The difference between Li and Na cell capacity most probably comes from the difference of standard potential of the two redox couples Li{sup +}/Li and Na{sup +}/Na of about ca. 0.3 V leading to an incomplete conversion reaction and thus lowers capacity in the case of Na cells. The Raman and IR ex-situ experiments after cycling indicate that the bipyridine organic ligands are completely decomposed during the electrochemical testing. The IR studies in MnV inorganic and MnBpy and MnBpy0.5 hybrid electrodes after the electrochemical cycling, suggest that the SEI formation and bipyridine degradation give rise to different aliphatic compounds. - Graphical abstract: The electrochemical performance of [(Mn(Bpy))(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 1.16} and [(Mn(Bpy){sub 0.5})(VO{sub 3}){sub 2}]?(H{sub 2}O){sub 0.62} against sodium and lithium counter electrodes give rise to the structural collapse of the initial compounds. The IR and Raman studies show that the Bpy organic ligand is completely decomposed during the during the electrochemical testing. However, after the amorphization stable capacities as high as 850 mAh/g for lithium cells were achieved. - Highlights: • We test the lithium and sodium insertion in hybrid brannerites. • Capacities as large as 850 mAh/g were obtained for the Li cells. • The capacity and good cycling is ascribed to a conversion reaction of the electrodes. • The Bpy molecule of the hybrid compounds is degraded during the first reduction. • The decomposition products of the Bpy ligand reduce the potential hysteresis.

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

    DEFF Research Database (Denmark)

    Dencker, Magnus; Hermansen, Bianca

    2011-01-01

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

  15. Diode-pumped efficient Yb:YGdVO4 thin-disk laser

    International Nuclear Information System (INIS)

    We report for the first time a continuous wave Yb0.06:Y0.32Gd0.62VO4 (Yb:YGdVO4) laser, based on the 2F5/2 – 2F7/2 transition. The free running Yb:YGdVO4 thin-disk laser oscillation takes place at many different wavelengths, covering a wide range of 1037.0 – 1042.2, 1028.4 – 1040.2, and 1021.9 – 1031.2 nm, for transmissions 0.5%, 1.0%, and 2.0%, respectively. As in the case of the 0.2 mm thick a-cut Yb:YGdVO4 the most efficient laser operation was achieved employing the coupler of 0.5%, producing a maximum output power of 2.25 W which gives an optical-to-optical efficiency of 21.2%, the slope efficiency being 37.3%

  16. Phase Transition in strongly-correlated VO2: Time-domain Assignment of Cause and Effect

    Science.gov (United States)

    Cavalleri, A.; Dekorsy, Th.; Chong, H. H.; Kieffer, J. C.; Schoenlein, R. W.

    We establish time-domain hierarchy between structural and electronic effects in the strongly correlated system VO2. The insulator-to-metal transition is driven directly by structural change rather than by electron-electron correlations.

  17. Phase Transition in strongly-correlated VO2: Time-domainAssignment of Cause and Effect

    Energy Technology Data Exchange (ETDEWEB)

    Cavalleri, A.; Dekorsy, Th.; Chong, H.H.; Kieffer, J.C.; Schoenlein, R.W.

    2004-07-22

    We establish time-domain hierarchy between structural andelectronic effects in the strongly correlated system VO2. Theinsulator-to-metal transition is driven directly by structural changerather than by electron-electron correlations.

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

    Directory of Open Access Journals (Sweden)

    Miloševi? Sanja

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Valerie R. Watzlaf

    2012-06-01

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

  20. Influence of thermal boundary conditions on the current-driven resistive transition in VO2 microbridges

    Science.gov (United States)

    Manca, Nicola; Kanki, Teruo; Tanaka, Hidekazu; Marré, Daniele; Pellegrino, Luca

    2015-10-01

    We investigate the resistive switching behaviour of VO2 microbridges under current bias as a function of temperature and thermal coupling with the heat bath. Upon increasing the electrical current bias, the formation of the metallic phase can progress smoothly or through sharp jumps. The magnitude and threshold current values of these sharp resistance drops show random behaviour and are dramatically influenced by thermal dissipation conditions. Our results also evidence how the propagation of the metallic phase induced by electrical current in VO2, and thus the shape of the resulting high-conductivity path, are not predictable. We discuss the origin of the switching events through a simple electro-thermal model based on the domain structure of VO2 films that can be useful to improve the stability and controllability of future VO2-based devices.

  1. Synthesis and characterization of VO2+ doped ZnO-CdS composite nanopowder

    Science.gov (United States)

    Thirumala Rao, G.; Babu, B.; Joyce Stella, R.; Pushpa Manjari, V.; Venkata Reddy, Ch.; Shim, Jaesool; Ravikumar, R. V. S. S. N.

    2015-02-01

    VO2+ doped ZnO-CdS composite nanopowder has been synthesized by chemical precipitation method. The prepared sample has been characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, photoluminescence (PL), optical absorption and EPR spectroscopy. From XRD pattern, average crystallite size is about 18 nm. SEM and TEM images showed sphere like structures. FT-IR spectrum indicates the presence of fundamental modes of ZnO, CdS and other functional groups. The PL spectrum of VO2+ doped ZnO-CdS composite nanopowder exhibits UV, blue and green emissions. Optical and EPR studies revealed the tetragonal compressed octahedral site symmetry for VO2+ ions. The bonding between VO2+ and its ligands is ionic.

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

    International Nuclear Information System (INIS)

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

  3. A new three-dimensional vanadium selenite, (VO)(2)(SeO3)(3), with isolated and edge-shared VO6 octahedra

    OpenAIRE

    Halasyamani, PS; O'Hare, D.

    1997-01-01

    Single crystals of (VO)2(SeO3)3 have been prepared from SeO2 and V2O5. The crystal structure has been determined by single-crystal X-ray diffraction. Crystal data: (VO)2(SeO3)3, Mr = 514.75; monoclinic, space group P21a (No. 14); cell parameters a = 9.151(1) Å, b = 6.353(1) Å, c = 14.992(1)Å, ? = 93.538(5)°, and Z = 4. The structure consists of VO6 octahedra and SeO3 groups. The vanadium octahedra either are edge-sharing and form [V2O6.66]3.33- groups or are corner-linked through an [SeO3/2]+...

  4. Prior Knowledge of Trial Number Influences the Incidence of Plateau at VO2max

    Directory of Open Access Journals (Sweden)

    Dan Gordon

    2015-01-01

    Full Text Available The purpose of this study was to assess the VO2max plateau response at VO2max during a series of pre-determined trials. METHODS: Ten male well-trained athletes (age, 23.0 ± 3.2; height, 183.3 ± 5.5 cm; mass 77.5 ± 11.1 Kg; VO2max 66.5 ± 5.0 ml.kg-1,min-1, but who were VO2max testing naïve and with prior-knowledge of trial number completed four incremental tests to volitional exhaustion, separated by ~72-h for the determination of VO2max and gas exchange threshold. Throughout all trials VO2max was recorded on a breath-by-breath basis using a pre-calibrated metabolic cart, using a plateau criterion of ? VO2 ?1.5 ml.kg-1.min-1 over the final 2 consecutive 30 s sampling periods. A significant difference was observed between trial-1 and trial-4 for plateau incidence (p = 0.0285 rising from 20% in trial-1 to a 70% response rate in trial-4. Furthermore a significant difference was observed for VO2dif (difference between criterion value and ? VO2 in trial-1, 1.02 ± 1.69 ml.kg-1.min-1 (p = 0.038, with non-significant differences observed for all other trials, despite a non-significant difference for VO2max across all trials (p > 0.05. Finally, a significant difference was observed for effort perception (RPE at volitional exhaustion between trial-1 (17.7 ± 1.3 and trial-4 (19.0 ± 1.4 (p = 0.0052. These data indicate that prior-knowledge of trial number can influence the manifestation of the VO2 plateau in a group of well-trained male athletes, thereby suggesting that a form of effort control is established in order to preserve the finite anaerobic capacity.

  5. Selective synthesis of monoclinic and tetragonal phase LaVO4 nanorods via oxides-hydrothermal route

    International Nuclear Information System (INIS)

    Pure monoclinic (m-) and tetragonal (t-) LaVO4 nanorods are successfully obtained via a facile oxides-hydrothermal method, in which V2O5 and La2O3 bulk powders are directly utilized as precursors without pretreatment. It is found that ethylenediamine tetraacetic disodium salt (EDTA) is a key factor for synthesizing t-LaVO4. The as-obtained products are characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and selected area electron diffraction (SAED). The FTIR spectra of VO4 around 800 cm-1 are suggested as an effective auxiliary means to identify the crystal phase of LaVO4. UV-Visible spectra of LaVO4 nanomaterials are obvious blue shift compared with the bulk m-LaVO4 materials. The different photoluminescent properties of Eu3+ doped m- and t-LaVO4 are demonstrated. A dissolution-precipitation mechanism is mainly responsible for the anisotropic morphology and phase control evolution of the LaVO4 nanocrystals. The oxides-hydrothermal system is also applicable to prepare other pure LnVO4 (Ln3+: Nd3+, Y3+, Sm3+) and doped LnVO4 nanomaterials

  6. Performance Study of Objective Speech Quality Measurement for Modern Wireless-VoIP Communications

    OpenAIRE

    Falk, Tiago H.; Wai-Yip Chan

    2009-01-01

    Wireless-VoIP communications introduce perceptual degradations that are not present with traditional VoIP communications. This paper investigates the effects of such degradations on the performance of three state-of-the-art standard objective quality measurement algorithms—PESQ, P.563, and an “extended” E-model. The comparative study suggests that measurement performance is significantly affected by acoustic background noise type and level as well as speech codec and packet ...

  7. Managing Risks at Runtime in VoIP Networks and Services

    OpenAIRE

    Dabbebi, Oussema; Badonnel, Remi; Festor, Olivier

    2010-01-01

    IP telephony is less confined than traditional PSTN telephony. As a consequence, it is more exposed to security attacks. These attacks are specific to VoIP protocols such as SPIT, or are inherited from the IP layer such as ARP poisoning. Protection mechanisms are often available, but they may seriously impact on the quality of service of such critical environments. We propose to exploit and automate risk management methods and techniques for VoIP infrastructures. Our objective is to dynamical...

  8. Cardiac output distribution in miniature swine during locomotory exercise to VO/sub 3max/

    International Nuclear Information System (INIS)

    Distribution of cardiac output (CO) was studied in miniature swine (22 +/- 1 kg) during level treadmill exercise up to the speed (17.7 km/hr) that elicited maximal oxygen consumption (VO/sub 2max/) (60 +/- 4 m1/min/kg). COs and tissue blood flows (BFs) were measured with the radiolabelled microsphere technique. CO increased from a preexercise value of 2.1 +/- 0.5 1/min up to 9.9 +/- 0.5 1/min at VO/sub 2max/. In preexercise standing 43% of CO went to skeletal muscle, which comprised 36 +/- 1% of body mass, 42% to viscera (12 +/- 1% mass), 5% to brain, heart, and lungs (2% +/- 0.1% mass), and 10% to skin and skeleton (35 +/- 2% mass). Preexercise could not be considered resting because of the animals' excitability. Skeletal muscle BF increased progressively with speed up to VO/sub 2max/, both in absolute terms and in percent CO. At VO/sub 2max/, 88% of CO went to muscle, 3% to viscera, 8% to brain, heart and lungs, and 1% to skin and skeleton. Thus, at VO/sub 2max/ only 4% of CO went to the inactive tissues, which constituted 47% of body mass. In 2 pigs that ran at speeds above 17 km/hr, total muscle BF leveled off at VO/sub 2max/. These findings demonstrate that muscle BF progressively increases up to VO/sub 2max/, and that VO2 levels off at the same intensity as muscle flow

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

    OpenAIRE

    Kinjal Shah; Satya Prakash Ghrera; Alok Thaker

    2012-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

  11. Prepaid and Postpaid VoIP Service Enhancements and Hybrid Network Performance Measurement

    OpenAIRE

    Mohd Nazri Ismail; Asaad Abusin

    2006-01-01

    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 r...

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

    OpenAIRE

    Mariana Gerber; Kerry-Lynn Thomson; Tian Gerber

    2013-01-01

    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 increase Information Security insurance premiums in the near future. Due to the dynamic nature of the technology, regulatory and legislative concerns such as lawful interception of communications and privacy m...

  13. Magnetic field dependence of the cooperative Jahn-Teller distortion in DyVO4

    International Nuclear Information System (INIS)

    The Jahn-Teller induced orthorhombic distortion in DyVO4 has been determined as a function of temperature and magnetic field up to 13 T by measurement of splitting of Esub(g) phonon modes of the tetragonal phase. The results are not well predicted by molecular field theory, reinforcing the conclusion from other experiments that short-range interactions are dominant in DyVO4. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Slack, Jonathan

    2013-05-14

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

  15. The relationship between speed and aerobic endurance (vo2max) in prepubertal children

    OpenAIRE

    Tar?k Sevindi; Selçuk Özda?; Çetin Yaman; Recep Kürkçü; Hale Hazar; Fatih Hazar

    2009-01-01

    The aim of this study was to determine the relationship between speed and aerobic endurance (VO2max) in prepubertal children. A total of twenty-three prepubertal children (age 11.44±0.72y); thirteen boys and ten prepubertal girls took part in this study. Each subject performed 20 m sprint test and 20m Shuttle Run Test. The relationship between speed and VO2max was analyzed by Spearman Correlation Test (p

  16. Slow component of VO2 kinetics: Mechanistic bases and practical applications

    DEFF Research Database (Denmark)

    Jones, Andrew M; Grassi, Bruno

    2011-01-01

    The V¿O2 slow component, a slowly-developing increase in V¿O2 during constant-work-rate (CWR) exercise performed above the lactate threshold, represents a progressive loss of skeletal muscle contractile efficiency and is associated with the fatigue process. This brief review outlines the current state of knowledge concerning the mechanistic bases of the V¿O2 slow component and describes practical interventions which can attenuate the slow componentand thus enhance exercise tolerance. There is strong evidence that, during CWR exercise, the development of the V¿O2 slow component is associated with the progressive recruitment of additional (type II) muscle fibers that are presumed to have lower efficiency. Recent studies, however, indicate that muscle efficiency is also lowered (resulting in a 'mirror-image'V¿O2 slow component) during fatiguing, high-intensity exercise in which additional fiber recruitment is unlikely or impossible. Therefore, it appears that muscle fatigue underpins the V¿O2 slow component, although the greater fatigue-sensitivity of recruited type II fibers might still play a crucial role in the loss of muscle efficiency in both situations.Several interventions can reduce the magnitude of the V¿O2slow component and these are typically associated with an enhanced exercise tolerance. These include endurance training, inspiratory muscle training, priming exercise, dietary nitrate supplementation, and the inspiration of hyperoxic gas. All of these interventions reduce muscle fatigue development either by improving muscle oxidative capacity and thus metabolic stability and/or by enhancing bulk muscle O2 delivery or local QO2-to- V¿O2 matching. Future honing of these interventions to maximize their impact on the V¿O2slow component might improve sports performance in athletes and exercise tolerance in the elderly or in patient populations.

  17. EPR and UV/VIS spectroscopic investigations of VO2+ complexes and compounds formed in alkali pyrosulfates

    DEFF Research Database (Denmark)

    Rasmussen, SØren Birk; Eriksen, Kim Michael

    2002-01-01

    The catalytically important molten salt-gas system M2S2O7-M2SO4-V2O5/SO2(g) (M = Na. K, Rb, Cs) has been investigated by X- and Q-band EPR spectroscopy. In order to obtain information about the V(IV) complex formation in the melts, samples rather dilute in V2O5 were quenched from the molten state at 450-460degreesC to 0degreesC. EPR spectra of the quenched samples were recorded on samples with alkali to vanadium (M/V) ratios 40, 80 and 160. The spectra show that two V(IV) complexes dominate in the melt regardless of the type of alkali metal ion. In systems with low activity of sulfate a paramagnetic V(IV) complex with g(parallel to) = 1.915, g(perpendicular to) = 1,978 and line widths 5-15 Gauss is observed. In systems saturated with M2SO4 the obtained EPR spectra show a paramagnetic complex with the g-tensors g(parallel to) = 1.930, g(perpendicular to) = 1.980 and line widths 20-60 Gauss. These results fit very well with the assumption that the species VO(SO4)(2)(2-) and SO42- are in equilibrium with VO(SO4)(3)(4-). It has also been shown for the system M2S2O7-M2SO4(sat)-V2O5/SO42-(g) that the line widths in the system increase with higher cation radius, and depend linearly on the volume fraction of the sample occupied by the cation. This indicates that spin-spin relaxation effects are the major contribution to line broadening. Combining information from UV/VIS and EPR spectra shows that the VO2+ unit in the molten salt solvent exhibits electronic properties close to aqueous solutions of V(IV).

  18. Mobile telephones: a comparison of radiated power between 3G VoIP calls and 3G VoCS calls.

    Science.gov (United States)

    Jovanovic, Dragan; Bragard, Guillaume; Picard, Dominique; Chauvin, Sébastien

    2015-01-01

    The purpose of this study is to assess the mean RF power radiated by mobile telephones during voice calls in 3G VoIP (Voice over Internet Protocol) using an application well known to mobile Internet users, and to compare it with the mean power radiated during voice calls in 3G VoCS (Voice over Circuit Switch) on a traditional network. Knowing that the specific absorption rate (SAR) is proportional to the mean radiated power, the user's exposure could be clearly identified at the same time. Three 3G (High Speed Packet Access) smartphones from three different manufacturers, all dual-band for GSM (900?MHz, 1800?MHz) and dual-band for UMTS (900?MHz, 1950?MHz), were used between 28 July and 04 August 2011 in Paris (France) to make 220 two-minute calls on a mobile telephone network with national coverage. The places where the calls were made were selected in such a way as to describe the whole range of usage situations of the mobile telephone. The measuring equipment, called "SYRPOM", recorded the radiation power levels and the frequency bands used during the calls with a sampling rate of 20,000 per second. In the framework of this study, the mean normalised power radiated by a telephone in 3G VoIP calls was evaluated at 0.75% maximum power of the smartphone, compared with 0.22% in 3G VoCS calls. The very low average power levels associated with use of 3G devices with VoIP or VoCS support the view that RF exposure resulting from their use is far from exceeding the basic restrictions of current exposure limits in terms of SAR. PMID:25352159

  19. Equações para a previsão da potência aeróbia (VO2 de jovens adultos brasileiros Equations for predicting aerobic power (VO2 of young Brazilian adults

    Directory of Open Access Journals (Sweden)

    Paula Magrani

    2010-06-01

    Full Text Available FUNDAMENTO: O VO2 pode ser previsto, com base em parâmetros antropométricos e fisiológicos, para determinadas populações. OBJETIVO: Propor modelos preditivos do VO2 submáximo e máximo para jovens adultos brasileiros. MÉTODOS: Os 137 voluntários (92 homens foram submetidos ao teste progressivo de esforço máximo (GXT no ciclo ergômetro (Monark®, Br. Medidas de trocas gasosas e ventilatórias foram realizadas em circuito aberto (Aerosport® TEEM 100, EUA. Em outro grupo, 13 voluntários foram submetidos ao GXT e a um teste de onda quadrada (SWT, para avaliar a validade externa das fórmulas do ACSM, de Neder et al e do nomograma de Åstrand-Ryhming. Adotou-se o delineamento experimental de validação cruzada e o nível de significância de p BACKGROUND: VO2 may be predicted with base on anthropometric and physiological parameters for determined populations. OBJECTIVE: To propose models for submaximal and maximal VO2 prediction in young Brazilian adults. METHODS: A total of 137 volunteers (92 men underwent graded maximal exercise test (GXT in a cycle ergometer (MonarkTM, Br. Gas exchange and respiratory measurements were performed in an open circuit (AerosportTM TEEM 100, USA. In another group, 13 volunteers underwent GXT and a square wave test (SWT in order to evaluate the external validity of Neder et al's formula, ACSM's formula, and of Åstrand-Ryhming nomogram. The study design chosen was a cross-validation and the significance level was set at p < 0.05. RESULTS: For men during submaximal exercises, a mathematical model was deduced with base on workload, body mass, and age, which explained 89% of the VO2 variation, with SEE (standard error of the estimate = 0.33 l.min-1. For the maximum load in the male group, another model with the same variables explained 71% of VO2 variation, with SEE = 0.40 l.min-1. For women, 93% of VO2 variation could be explained, with SEE = 0.17 l.min-1, both in submaximal and maximal exercise, with only one equation by use e of the same independent variables. CONCLUSION: The models derived in the present study proved to be accurate to predict submaximal and maximal VO2 in young Brazilian adults. (Arq Bras Cardiol. 2010; [online]. ahead print, PP.0-0

  20. 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)

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

    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 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.

  1. The performance model of dynamic virtual organization (VO) formations within grid computing context

    International Nuclear Information System (INIS)

    Grid computing aims to enable 'resource sharing and coordinated problem solving in dynamic, multi-institutional virtual organizations (VOs)'. Within the grid computing context, successful dynamic VO formations mean a number of individuals and institutions associated with certain resources join together and form new VOs in order to effectively execute tasks within given time steps. To date, while the concept of VOs has been accepted, few research has been done on the impact of effective dynamic virtual organization formations. In this paper, we develop a performance model of dynamic VOs formation and analyze the effect of different complex organizational structures and their various statistic parameter properties on dynamic VO formations from three aspects: (1) the probability of a successful VO formation under different organizational structures and statistic parameters change, e.g. average degree; (2) the effect of task complexity on dynamic VO formations; (3) the impact of network scales on dynamic VO formations. The experimental results show that the proposed model can be used to understand the dynamic VO formation performance of the simulated organizations. The work provides a good path to understand how to effectively schedule and utilize resources based on the complex grid network and therefore improve the overall performance within grid environment.

  2. On-line Monitoring of VoIP Quality Using IPFIX

    Directory of Open Access Journals (Sweden)

    Petr Matousek

    2014-01-01

    Full Text Available The main goal of VoIP services is to provide a reliable and high-quality voice transmission over packet networks. In order to prove the quality of VoIP transmission, several approaches were designed. In our approach, we are concerned about on-line monitoring of RTP and RTCP traffic. Based on these data, we are able to compute main VoIP quality metrics including jitter, delay, packet loss, and finally R-factor and MOS values. This technique of VoIP quality measuring can be directly incorporated into IPFIX monitoring framework where an IPFIX probe analyses RTP/RTCP packets, computes VoIP quality metrics, and adds these metrics into extended IPFIX flow records. Then, these extended data are stored in a central IPFIX monitoring system called collector where can be used for monitoring purposes. This paper presents a functional implementation of IPFIX plugin for VoIP quality measurement and compares the results with results obtained by other tools.

  3. VoIP over Multiple IEEE 802.11 Wireless LANs

    CERN Document Server

    Chan, A

    2007-01-01

    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 and 10.34 sessions per AP, respectively. This paper investigates several solutions to improve the VoIP capacity. Based on a conflict graph model, we propose a clique-analytical call-admission scheme, which increases the VoIP capacity by 52% and 37% in 802.11b and 802.11g respectively. If all the three orthogonal frequency channels available in 11b and 11g are used, the capacity can be nearly tripled by the call-admission scheme. This paper also proposes for the first time the use of coarse-grained time-division multiple access (CoTDMA) in ...

  4. Single crystal and magnetic structures of maricite-type AgMnVO4

    Science.gov (United States)

    Ben Yahia, Hamdi; Shikano, Masahiro; Gaudin, Etienne; Avdeev, Maxim; Ling, Chris D.

    2015-01-01

    Single crystals of the ternary manganese vanadate AgMnVO4, were grown using AgVO3 flux. The structure was determined from single crystal X-ray diffraction data. The magnetic structure and properties of AgMnVO4 were characterized by magnetic susceptibility, specific heat, and low-temperature neutron powder diffraction measurements. AgMnVO4 crystallizes in the maricite-type structure with space group Pnma, a=9.5393(12), b=6.8132(9), c=5.3315(7) Å and Z=4. AgMnVO4 contains MnO4 chains made up of edge-sharing MnO6 octahedra, and these chains are interlinked by the VO4 and AgO4 tetrahedra. The specific heat measurements indicate a 3D-antiferromagnetic ordering at ~12.1 K and the neutron powder diffraction measurements at 5 K show that the Mn2+magnetic moments are antiferromagnetically coupled within the chains which are antiferromagnetically coupled to each other.

  5. Microemulsion-mediated hydrothermal synthesis and characterization of zircon-type LaVO4 nanowires

    International Nuclear Information System (INIS)

    The zircon-type tetragonal (t-) LaVO4 nanowires were controlled synthesized by a new approach, a microemulsion-mediated hydrothermal method, in which the aqueous cores of sodium dodecyl sulfate (SDS)/cyclohexane/n-hexanol/water microemulsion were used as constrained microreactors for a controlled growth of t-LaVO4 nanocrystals under hydrothermal conditions. The microemulsion exists stably just at room temperature and not under hydrothermal conditions, in addition, the as-obtained nanowires are much larger than the microemulsion droplets, so that the microemulsion does not simply act as a template, but rather directs crystal growth into nanowires presumably by interacting with the surface of the growing crystal. A series of experimental results indicated that several experimental parameters, such as the SDS concentration, the species and content of the cosurfactant play important roles in the morphological control of the t-LaVO4 nanocrystals. Possible formation mechanism of t-LaVO4 nanowires is also discussed. - Graphical abstract: The zircon-type tetragonal (t-) LaVO4 nanowires were controlled synthesized by a microemulsion-mediated hydrothermal method, in which the aqueous cores of SDS/cyclohexane/n-hexanol/water microemulsion were used as constrained microreactors for a controlled growth of t-LaVO4 nanocrystals under hydrothermal conditions

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

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per

    2011-01-01

    Abstract Objective. Aerobic fitness, defined as maximum oxygen uptake (VO(2PEAK)), and body fat measurements represent two known risk factors for disease. The purpose of this study was to investigate the relationship between VO(2PEAK) and body fat measurements in young children at a population-based level. Methods. Cross-sectional study of 225 children (128 boys and 97 girls) aged 8-11 years, recruited from a population-based cohort. Total lean body mass (LBM), total fat mass (TBF), and abdominal fat mass (AFM) were measured by dual-energy x-ray absorptiometry. Body fat was also calculated as a percentage of body mass (BF%) and body fat distribution as AFM/TBF. VO(2PEAK) was assessed by indirect calorimetry during maximal exercise test. Results. Significant relationships existed between body fat measurements and VO(2PEAK) in both boys and girls, with Pearson correlation coefficients for absolute values of VO(2PEAK) (0.22-0.36, P<0.05), and for VO(2PEAK) scaled by body mass (-0.38 - -0.70, P

  7. First-principles study of multiferroic material PbVO3 under uniaxial pressure

    Science.gov (United States)

    Ming, Xing; Hu, Fang; Du, Fei; Wei, Ying-Jin; Chen, Gang

    2015-09-01

    First-principles calculations are performed to simulate the tetragonal multiferroic material PbVO3 under uniaxial pressure. A first-order tetragonal to cubic structural phase transition takes place under uniaxial pressure of 1.2 GPa, which is accompanied by abruptly changes of the structural parameters, lattice volume, and atomic displacements. Comparative electronic structure calculations are performed for PbVO3 with the generalised gradient approximation (GGA) and the B3LYP hybrid functional. The hybrid functional drastically improves the band gap of the ground state of PbVO3. The GGA and the B3LYP hybrid functional predict contradictory electronic structures for the high pressure cubic phase of PbVO3. The results of the B3LYP hybrid functional calculation disprove the metallisation of PbVO3 under uniaxial pressure. The insulating electronic structure reproduced with B3LYP is consistent with recent experimental observations of semiconducting behaviour for the high pressure cubic phase of PbVO3.

  8. Chapter 18: Web-based Tools - NED VO Services

    Science.gov (United States)

    Mazzarella, J. M.; NED Team

    The NASA/IPAC Extragalactic Database (NED) is a thematic, web-based research facility in widespread use by scientists, educators, space missions, and observatory operations for observation planning, data analysis, discovery, and publication of research about objects beyond our Milky Way galaxy. NED is a portal into a systematic fusion of data from hundreds of sky surveys and tens of thousands of research publications. The contents and services span the entire electromagnetic spectrum from gamma rays through radio frequencies, and are continuously updated to reflect the current literature and releases of large-scale sky survey catalogs. NED has been on the Internet since 1990, growing in content, automation and services with the evolution of information technology. NED is the world's largest database of crossidentified extragalactic objects. As of December 2006, the system contains approximately 10 million objects and 15 million multi-wavelength cross-IDs. Over 4 thousand catalogs and published lists covering the entire electromagnetic spectrum have had their objects cross-identified or associated, with fundamental data parameters federated for convenient queries and retrieval. This chapter describes the interoperability of NED services with other components of the Virtual Observatory (VO). Section 1 is a brief overview of the primary NED web services. Section 2 provides a tutorial for using NED services currently available through the NVO Registry. The "name resolver" provides VO portals and related internet services with celestial coordinates for objects specified by catalog identifier (name); any alias can be queried because this service is based on the source cross-IDs established by NED. All major services have been updated to provide output in VOTable (XML) format that can be accessed directly from the NED web interface or using the NVO registry. These include access to images via SIAP, Cone- Search queries, and services providing fundamental, multi-wavelength extragalactic data such as positions, redshifts, photometry and spectral energy distributions (SEDs), and sizes (all with references and uncertainties when available). Section 3 summarizes the advantages of accessing the NED "name resolver" and other NED services via the web to replace the legacy "server mode" custom data structure previously available through a function library provided only in the C programming language. Section 4 illustrates visualization via VOPlot of an SED and the spatial distribution of sources from a NED All-Sky (By Parameters) query. Section 5 describes the new NED Spectral Archive, illustrating how VOTables are being used to standardize the data and metadata as well as the physical units of spectra made available by authors of journal articles and producers of major survey archives; quick-look spectral analysis through convenient interoperability with the SpecView (STScI) Java applet is also shown. Section 6 closes with a summary of the capabilities described herein, which greatly simplify interoperability of NED with other components of the VO, enabling new opportunities for discovery, visualization, and analysis of multiwavelength data.

  9. 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)

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

    2010-12-01

    Full Text Available 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.

  10. 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)

    Marceliano, Segura; Aníbal, Aliaga.

    2013-09-01

    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. 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.

  11. Factores de expansión de biomasa en comunidades forestales templadas del norte de Durango, México / Biomass expansion factors in temperate forest communities of north Durango

    Scientific Electronic Library Online (English)

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

    2010-06-01

    Full Text Available La biomasa forestal, por lo general, es cuantificada en kilogramos por árbol o en toneladas por hectárea de peso verde o de peso seco. En un bosque es un elemento ambiental clave para calcular los montos de carbono que puedan liberarse a la atmósfera o bien fijarse, cuando estos ecosistemas son mane [...] jados para mitigar los gases de efecto invernadero. El presente trabajo se llevó a cabo en el norte del estado de Durango, México, con el objetivo de estimar la biomasa arbórea aérea (M) y los factores de expansión de biomasa (FEB) mediante ecuaciones alométricas para los diferentes componentes que provienen de inventarios forestales. Los datos de campo y de laboratorio que se registraron fueron peso verde y peso seco de las ramas y del fuste. La estimación de M se realizó mediante dos procedimientos: 1) con ecuaciones alométricas utilizando el diámetro normal como variable independiente y 2) con la ecuación clásica de física que considera el volumen y la densidad básica de la madera. Habiendo calculado M y los volúmenes por hectárea (ERH) de los inventarios forestales convencionales, se obtuvieron los valores de FEB. Los resultados mostraron diferencias en los métodos para conocer M y, por consiguiente los FEB; el primero parece más sensible y ofrece una mejor representación del fenómeno que el segundo. Los FEB son dependientes de la altura promedio del rodal y de la densidad de la madera; los derivados de los datos de inventario, se distribuyen de forma normal. Abstract in english Forest biomass is generally quantified in kilograms of green or dry weight per tree or in tons per area. It is an environmental key element to assess the carbon amounts that can go to the atmosphere or be fixed when these ecosystems are managed to mitigate the greenhouse-effect gases. This research [...] was conducted in northern Mexico in order to assess the biomass components and biomass expansion factors, with the use of alometric component equations and the classical physics equation that uses wood specific gravity applied to forest inventory data. Field and laboratory recorded data consisted on fresh and oven dried weight of stem and branch components. Biomass estimations were conducted following two procedures: 1) using an alometric equation that feeds with normal diameter and 2) employing the wood specific gravity times volume. Once biomass was estimated at the stand level it was divided by stand volume derived from inventory data to calculate the biomass expansion factors. The results showed differences in methods of estimating biomass and therefore in expansion factors as well. Biomass expansion factors are dependent on the mean top height of trees and wood specific gravity. These parameters are normally distributed for the inventory data utilized.

  12. Conversion efficiency of photosynthetically active radiation intercepted in biomass in stands of black wattle in Brazil / Eficiencia de conversión de la radiación fotosintéticamente activa interceptada en biomasa en rodales de acacia negra en Brasil

    Scientific Electronic Library Online (English)

    Alexandre, Behling; Carlos Roberto, Sanquetta; Ana Paula, Dalla Corte; Braulio, Caron; Augusto Arlindo, Simon; Marcos, Behling; Denise, Schmidt.

    Full Text Available El rendimiento en biomasa es una función de la eficiencia de conversión de radiación fotosintéticamente activa interceptada en fotoasimilados y varía, dependiendo de las condiciones en que se cultiva una planta. Este estudio cuantificó la eficiencia de conversión de la radiación solar interceptada p [...] or la biomasa fotosintéticamente activa (?b) en rodales acacia negra (Acacia mearnsii). Se realizó un estudio en rodales de 1-7 años de edad en dos sitios (para abarcar el ciclo completo de cultivo de la especie), en que se determinaron la radiación fotosintéticamente activa interceptada (PARI), el índice de área foliar, el coeficiente de extinción de la luz y el rendimiento de biomasa. Se propuso un sistema de ecuaciones que expresó como la radiación fotosintética es interceptada y los asimilados se convierten. El sistema de ecuaciones estima el rendimiento de biomasa y al mismo tiempo predice la partición de la biomasa dentro del árbol. El rendimiento en biomasa de acacia negra se relacionó linealmente con RFAi y la ?b de la biomasa total de acacia negra fue 0,0021 kg MJ"¹. Abstract in english Biomass yield is a function of the conversion efficiency of photosynthetically active radiation intercepted in photoassimilates and varies depending on the conditions in which a plant is grown. Thus, this study sought to quantify the conversion efficiency of solar radiation intercepted by photosynth [...] etically active biomass (?b) in black wattle stands (Acacia mearnsii De Wild.). A study was therefore conducted in 1-7 year-old stands of the species in two sites (to span one plantation cycle), in which intercepted photosynthetically active radiation (PARi), leaf area index, light extinction coefficient and biomass yield were determined. A system of equations is proposed, therefore, as photosynthetic radiation is intercepted and assimilates are converted, the system of equations estimates biomass yield, and at the same time predicts the biomass partition within the tree. The biomass yield of black wattle was linearly related to PARi and the ?b of the total biomass of black wattle is 0.0021 kg MJ-1.

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

    Scientific Electronic Library Online (English)

    Eduardo Camillo, Martinez; Macos de Sá Rego, Fortes; Luiz Antônio dos, Anjos.

    2011-06-01

    Full Text Available FUNDAMENTO: A adiponectina é considerada importante fator na patogênese das doenças cardiovasculares e metabólicas, por suas propriedades antiaterogênicas e antiinflamatórias. Poucos estudos, entretanto, sugerem a existência de relação direta entre os níveis de adiponectina e os níveis de condiciona [...] mento cardiorrespiratório e atividade física. OBJETIVO: Verificar a influência do estado nutricional e do condicionamento cardiorrespiratório nos níveis plasmáticos de adiponectina em homens adultos. MÉTODOS: Foram avaliados 250 sujeitos, homens, todos militares da ativa do Exército Brasileiro (42,6 ± 4,8 anos). Foram mensurados os níveis plasmáticos de adiponectina, massa corporal, estatura, circunferência da cintura (CC), percentual de gordura por pesagem hidrostática e VO2max por ergoespirometria. Um questionário foi utilizado para obter as características do treinamento físico realizado pelos sujeitos. RESULTADOS: Na amostra, 121 (48%) sujeitos apresentaram sobrepeso e 36 (14%) eram obesos. Ainda, 66 sujeitos (27%) apresentaram percentual de gordura maior que 25% e 26.7% apresentaram CC > 94 cm. Sujeitos com sobrepeso e obesidade apresentaram valores significativamente menores de adiponectina em relação aqueles com estado nutricional normal. Sujeitos no mais alto tercil de VO2max apresentaram níveis de adiponectina mais altos que os demais. Os níveis de adiponectina estiveram positivamente correlacionados com o tempo total de treinamento físico semanal e com o VO2max e inversamente correlacionados com os valores de massa corporal, IMC e CC. A correlação dos níveis de adiponectina e do VO2max não permaneceu significante após controlada pelo IMC e CC. CONCLUSÃO: Sujeitos com melhor condicionamento cardiorrespiratório e com estado nutricional normal parecem apresentar níveis mais saudáveis de adiponectina. Abstract in spanish FUNDAMENTO: La adiponectina es considerada un importante factor en la patogénesis de las enfermedades cardiovasculares y metabólicas, por sus propiedades antiaterogénicas y antiinflamatorias. Sin embargo, hay pocos estudios que sugieran la existencia de una relación directa entre los niveles de adip [...] onectina y los niveles de condicionamiento cardiorrespiratorio y la actividad física. OBJETIVO: Verificar la influencia del estado nutricional y del condicionamiento cardiorrespiratorio en los niveles plasmáticos de adiponectina en hombres adultos. MÉTODOS: Se evaluaron 250 individuos hombres, todos militares en activo del Ejército Brasileño (42.6 ± 4.8 años). Se midieron los niveles plasmáticos de adiponectina, masa corporal, altura, circunferencia de la cintura (CC), porcentaje de grasa corporal por peso hidrostático y condicionamiento cardiorespiratorio por ergoespirometria. Un cuestionario se usó para obtener las características del entrenamiento físico realizado por los individuos. RESULTADOS: En la muestra, 121 (48%), de los individuos presentaron sobrepeso y 36 (14%) eran obesos. Además, 66 individuos (27%), presentaron un porcentaje de grasa corporal mayor que el 25%, y el 26,7% presentaron CC > 94 cm. Los individuos con sobrepeso y obesidad presentaron valores significativamente menores de adiponectina con relación a los que tenían un estado nutricional normal. Los individuos con el más elevado tercil de condicionamiento cardiorespiratorio, presentaron niveles de adiponectina más altos que los demás. Los niveles de adiponectina quedaron positivamente correlacionados con el tiempo total de entrenamiento físico semanal y con el condicionamiento cardiorespiratorio, e inversamente correlacionados con los valores de masa corporal, IMC y CC. La correlación de los niveles de adiponectina y del condicionamiento cardiorespiratorio no permanecieron significativos después del control del IMC y CC. CONCLUSIÓN: Los individuos con un mejor condicionamiento cardiorrespiratorio y con un estado nutricional normal parecen presentar niveles más sanos de adiponectina. Abstract in english BACKGROUND: Adiponectin is consid

  14. Selective synthesis and visible-light photocatalytic activities of BiVO4 with different crystalline phases

    International Nuclear Information System (INIS)

    Tetragonal and monoclinic bismuth vanadate (BiVO4) powders were selectively synthesized by aqueous processes. The characterizations of the as-prepared BiVO4 powders were carried out by X-ray diffraction, nitrogen adsorption, scanning electron microscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic activities of different BiVO4 samples were determined by degradation of methylene blue solution under visible-light irradiation (? > 420 nm) and compared with that of TiO2 (Degussa P25). The band gaps of the as-prepared BiVO4 were determined from UV-vis diffuse reflectance spectra. It was found that monoclinic BiVO4 with a band gap of 2.34 eV showed higher photocatalytic activity than that of tetragonal BiVO4 with a band gap of 3.11 eV

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

    Science.gov (United States)

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

    2015-08-28

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

  16. 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)

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

    2012-04-01

    Full Text Available 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.

  17. 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)

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

    2013-12-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2013-03-01

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

  19. VO-KOREL: A Fourier disentangling service of Virtual Observatory

    CERN Document Server

    Škoda, Petr; Fuchs, Jan

    2011-01-01

    VO-KOREL is a web service exploiting the technology of Virtual Observatory for providing the astronomers with the intuitive graphical front-end and distributed computing back-end running the most recent version of Fourier disentangling code KOREL. The system integrates the ideas of the e-shop basket, conserving the privacy of every user by transfer encryption and access authentication, with features of laboratory notebook, allowing the easy housekeeping of both input parameters and final results, as well as it explores a newly emerging technology of cloud computing. While the web-based front-end allows the user to submit data and parameter files, edit parameters, manage a job list, resubmit or cancel running jobs and mainly watching the text and graphical results of a disentangling process, the main part of the back-end is a simple job queue submission system executing in parallel multiple instances of FORTRAN code KOREL. This may be easily extended for GRID-based deployment on massively parallel computing cl...

  20. Transport phenomena in SrVO3 thin films

    Science.gov (United States)

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

    2013-03-01

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

  1. Stream or Block Cipher for Securing VoIP?

    Directory of Open Access Journals (Sweden)

    Ashraf D. Elbayoumy

    2007-09-01

    Full Text Available When the network is homogeneous, choosing the cipher type for apacket telephony application is simple. It is clear that streamciphers perform better than block ciphers over landline,circuit-switched networks, since loss is negligible in thesenetworks but corruption is not. Likewise, it is also clear thatblock ciphers perform better than stream ciphers over landline,packet-switched networks, since corruption is negligible in thesenetworks but loss is not [9]. However, the choice of cipheris not so clear for a heterogeneous internetwork containing a mixof packet and circuit-switched networks. Additionally, this issuebecomes even more confounded when heterogeneous internetwork alsoconsists of wireless links. Existing encryption systems willdegrade performance in a heterogeneous internetwork because suchinternetworks have appreciable loss and corruption. Thus, theerror properties would degrade the subjective quality of thepacket telephony application. In this paper we present anexperimental results of comparing block and stream ciphers whenused to secure VoIP in terms of end-to-end delay and subjectivequality of perceived voice.We proposed a new technique, which provides automaticsynchronization of stream ciphers on a per packet basis, withoutthe overhead of an initialization vector in packet headers orwithout maintaining any state of past-encrypted data. We show thatthis technique mitigates the trade-off between subjective qualityand confidentiality.

  2. 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)

    Diego Mauricio, Yepes Maya; Farid, Chejne Janna.

    2012-12-01

    Full Text Available 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.

  3. Aspectos fisiológicos de estevia (Stevia rebaudiana Bertoni en el Caribe colombiano: I. Efecto de la radiación incidente sobre el área foliar y la distribución de biomasa

    Directory of Open Access Journals (Sweden)

    Jarma Alfredo

    2005-12-01

    Full Text Available

    Stevia rebaudiana Bertoni es uno de los 154 miembros del genero Stevia. El componente edulcorante de sus hojas se debe a glucosidos de diterpeno. Los principales glucosidos de esteviol son: esteviosido, rebaudiosido A, rebaudiosido C y dulcosido A. Este trabajo se realizo en Monteria (Colombia, con el proposito de evaluar el efecto de cuatro niveles de radiacion incidente sobre el comportamiento fisiologico de S. rebaudiana, bajo las condiciones ambientales delvalle del Sinu, en el Caribe colombiano. Se planteo un diseno completo al azar con arreglo factorial, en el que los factores fueron los porcentajes de la radiacion incidente en la region (19%, 24%, 56% y 100% y los genotipos de estevia ‘Morita 1’ y ‘Morita 2’. Los resultados indicaron que el area foliar de ‘Morita 2’ es superior a ‘Morita 1’, independientemente de la radiacion. Los altos niveles de radiacion incidente (100% y 56% registraron la mayor acumulacion de biomasa de las hojas, siendo superior en ‘Morita 2’. La mayor proporcion de la biomasa de las hojas, con respecto a la del tallo, en los primeros 60 d indica que la planta se dedico a fortalecer su aparato fotosintetico; luego, la migracion de fotoasimilados se hizo en mayor proporcion hacia los tallos, terminando con una tendencia estable hacia ambas demandas.

  4. Predicción del contenido intracelular de trehalosa en el proceso de producción de biomasa de Saccharomyces cerevisiae / Predicting trehalose cytoplasmic content during a Saccharomyces cerevisiae biomass production process

    Scientific Electronic Library Online (English)

    J. S., Aranda; A. I., Cabrera; J. I., Chairez.

    2008-04-01

    Full Text Available La trehalosa es un carbohidrato dimérico componente de la levadura de panificación Saccharomyces cerevisiae, y es considerado como indicador de la capacidad fermentativa y de la viabilidad de las células. En procesos de producción de levadura, se busca inducir una acumulación intracelular de trehalo [...] sa. Por ser un compuesto citoplásmico, la cuantificación de la trehalosa requiere de tomas de muestra y de métodos analíticos posteriores. Así, el conocimiento del contenido citoplásmico de trehalosa es siempre ulterior al desarrollo del proceso de producción de biomasa, y esto dificulta el ajuste en tiempo real de parámetros de operación para incrementar la cantidad de trehalosa en la biomasa. Por tanto, se requiere de alguna alternativa para estimación de la trehalosa intracelular en tiempo real. Este trabajo presenta una opción de predicción basada tanto en el metabolismo celular implicado durante la biosíntesis de trehalosa, como en un algoritmo de redes neuronales dinámicas para la estimación de la concentración intracelular del carbohidrato. Abstract in english Trehalose is a dimeric carbohydrate and yeast biomass component generally used as an indicator of good viability and fermentation capacity. Yeast biomass production processes aim at inducing an intracellular accumulation of trehalose. However, during a production process, the trehalose must be quant [...] ified by off-line analytical methods after sample taking because it is a cytoplasmic compound. Thus, knowing experimental measurements of yeast trehalose content is always delayed. As a result, not oportune actions can be implemented in order to lead the production process toward a high intracellular trehalose accumulation in the produced biomass. Therefore, an online estimation method to forecast real-time intracellular trehalose content in yeast is developed. It is based on the main metabolic events involved in trehalose biosynthesis, as well as on a differential neural network algorithm to estimate trehalose concentration in the cytoplasm.

  5. SIP Signalling and QoS for VoIP over IPv6 DVB-RCS Satellite Networks

    OpenAIRE

    ALI, M.; Liang, L.; Sun, Z.; Cruickshank, HS

    2009-01-01

    With the rapid development of the Internet, new technologies and applications are emerging. One of the important applications is voice over IP. Satellites are playing an important role to provide VoIP services with their global coverage and onboard processing ability over IP networks. Satellite network environment, generally characterized by large delay and erroneous link, is considered to be unfriendly to VoIP. The performance of VoIP is adversely influenced by these demerits. The performanc...

  6. Preparation, characterization and enhanced visible-light photocatalytic activities of BiPO4/BiVO4 composites

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • BiPO4/BiVO4 composites were successfully prepared by the hydrothermal method. • BiPO4/BiVO4 composites exhibited broad absorption in the visible region. • Visible-light photocatalytic activities of BiPO4/BiVO4 composites were enhanced. • P/V molar ratio and pH value of the reaction affect photocatalytic activity. • The mechanism of enhanced visible-light photocatalytic activities was discussed. - Abstract: BiPO4/BiVO4 composites with different P/V molar ratios were prepared by the hydrothermal method and the effect of pH values of hydrothermal reaction on photocatalytic activity of BiPO4/BiVO4 composite was investigated. The photocatalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectroscopy. The photocatalytic property of BiPO4/BiVO4 was evaluated by photocatalytic degradation of Methylene blue under visible light irradiation. The results showed that the photocatalytic activity of the composites was much higher than that of pure BiPO4 and BiVO4. The rate constant of Methylene blue degradation over BiPO4/BiVO4 (P/V molar ratio of 5:1 and hydrothermal reaction pH value of 1.5) is 1.7 times that of pure BiVO4. The photocatalytic activity enhancement of BiPO4/BiVO4 composite is closely related to the BiVO4 functioning as a sensitizer to adsorb visible light and the heterojunction of BiPO4/BiVO4 acting as an active center for hindering the rapid recombination of electron–hole pairs during the photocatalytic reaction

  7. Upconversion spectrum of Tm,Ho:GdVO4 pumped by pulse and CW laser at 800 nm

    International Nuclear Information System (INIS)

    The different upconversion dynamic processes in Tm,Ho:GdVO4 crystal pumped by 100 fs pulse laser and continue-wave diode laser at 800 nm are analyzed. A phonon-helped absorption theory is used to explain the different upconversion processes in Tm,Ho:YLF and Tm,Ho:GdVO4. In addition, the lifetime 16 ?s of Ho:5S2 level in GdVO4 is firstly measured

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

    International Nuclear Information System (INIS)

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

  9. 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)

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

    2014-04-01

    Full Text Available 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.

  10. Synthesis, characterization and catalytic activity of two novel cis - dioxovanadium(V) complexes: [VO{sub 2}(L)] and [VO{sub 2}(HLox)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natalia M.L.; Chacon, Eluzir P.; Resende, Jackson A.L.C.; Carneiro, Jose Walkimar de M.; Lanznaster, Mauricio, E-mail: mlanz@vm.uff.b [Universidade Federal Fluminense (IQ/UFF), Niteroi, RJ (Brazil). Inst. de Quimica; Pinheiro, Carlos B. [Universidade Federal de Minas Gerais (DF/UFMG), Belo Horizonte (Brazil). Dept. de Fisica; Fernandez, Tatiana L.; Scarpellini, Marciela [Universidade Federal do Rio de Janeiro (IQ/UFRJ), RJ (Brazil). Inst. de Quimica

    2011-07-01

    Two novel complexes, [VO{sub 2}(L)] (1) and [VO{sub 2}(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, H{sub 2}Lox, is also described. Complexes 1 and 2 were obtained by the reaction of [VO(acac){sub 2}] with the ligands HL and H{sub 2}Lox, 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{sup -}, respectively, in a distorted octahedral environment. The catalytic activity of these compounds towards cyclohexane oxidation was evaluated using H{sub 2}O{sub 2} 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. (author)

  11. Coupling effect between the structure and surface characteristics of electrospun carbon nanofibres on the electrochemical activity towards the VO2(+)/VO(2+) redox couple.

    Science.gov (United States)

    Wei, Guanjie; Gao, Zhenguo; Wei, Zengfu; Fan, Xinzhuang; Liu, Jianguo; Yan, Chuanwei

    2015-08-21

    In order to investigate the structure-function relationship of electrospun carbon nanofibres (ECNFs), polyacrylonitrile (PAN)-based electrospun carbon webs (ECWs) have been developed, consisting of ECNFs carbonized over the temperature range of 1000-1500 °C in a nitrogen atmosphere. The surface morphology, microstructure, composition, electrical conductivity and hydrophilicity of the ECNFs have been characterized. The electrochemical activity of the ECNFs towards the VO2(+)/VO(2+) redox reaction has been measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is worth noting that the electrochemical performance of the ECNFs decreases firstly and then rises gradually with the increase in carbonization temperature, and a carbonization temperature of about 1300 °C is the turning point. This unusual phenomenon might be attributed to the coupling effect between the surface and structure characteristics of the ECNFs towards the VO2(+)/VO(2+) redox couple. The surface composition plays a leading role in the electrochemical activity of ECNFs carbonized over the temperature range of 1000-1300 °C; however, the edge planes of graphite crystallites which form during the high temperature range from 1300-1500 °C then become the dominant factor. Therefore, the electrochemical activity decreases with the reduction of functional groups on the surface from carbonization at 1000-1300 °C, and then increases with the addition of the edge planes of graphite crystallites from carbonization at 1300-1500 °C. PMID:26194622

  12. Equações para a previsão da potência aeróbia (VO2) de jovens adultos brasileiros / Equations for predicting aerobic power (VO2) of young Brazilian adults

    Scientific Electronic Library Online (English)

    Paula, Magrani; Fernando Augusto Monteiro Saboia, Pompeu.

    2010-06-01

    Full Text Available FUNDAMENTO: O VO2 pode ser previsto, com base em parâmetros antropométricos e fisiológicos, para determinadas populações. OBJETIVO: Propor modelos preditivos do VO2 submáximo e máximo para jovens adultos brasileiros. MÉTODOS: Os 137 voluntários (92 homens) foram submetidos ao teste progressivo de es [...] forço máximo (GXT) no ciclo ergômetro (Monark®, Br). Medidas de trocas gasosas e ventilatórias foram realizadas em circuito aberto (Aerosport® TEEM 100, EUA). Em outro grupo, 13 voluntários foram submetidos ao GXT e a um teste de onda quadrada (SWT), para avaliar a validade externa das fórmulas do ACSM, de Neder et al e do nomograma de Åstrand-Ryhming. Adotou-se o delineamento experimental de validação cruzada e o nível de significância de p Abstract in english BACKGROUND: VO2 may be predicted with base on anthropometric and physiological parameters for determined populations. OBJECTIVE: To propose models for submaximal and maximal VO2 prediction in young Brazilian adults. METHODS: A total of 137 volunteers (92 men) underwent graded maximal exercise test ( [...] GXT) in a cycle ergometer (MonarkTM, Br). Gas exchange and respiratory measurements were performed in an open circuit (AerosportTM TEEM 100, USA). In another group, 13 volunteers underwent GXT and a square wave test (SWT) in order to evaluate the external validity of Neder et al's formula, ACSM's formula, and of Åstrand-Ryhming nomogram. The study design chosen was a cross-validation and the significance level was set at p

  13. In situ high-pressure synchrotron x-ray diffraction study of CeVO4 and TbVO4 up to 50 GPa

    CERN Document Server

    Errandonea, D; Achary, S N; Tyagi, A K; 10.1103/PhysRevB.84.024111

    2012-01-01

    Room temperature angle-dispersive x-ray diffraction measurements on zircon-type TbVO4 and CeVO4 were performed in a diamond-anvil cell up to 50 GPa using neon as pressure-transmitting medium. In TbVO4 we found at 6.4 GPa evidence of a non-reversible pressure-induced structural phase transition from zircon to a scheelite-type structure. A second transition to an M-fergusonite-type structure was found at 33.9 GPa, which is reversible. Zircon-type CeVO4 exhibits two pressure-induced transitions. First an irreversible transition to a monazite-type structure at 5.6 GPa and second at 14.7 GPa a reversible transition to an orthorhombic structure. No additional phase transitions or evidences of chemical decomposition are found in the experiments. The equations of state and axial compressibility for the different phases are also determined. Finally, the sequence of structural transitions and the compressibilities are discussed in comparison with other orhtovanadates and the influence of non-hydrostaticity commented.

  14. Preparation and characterizations of BiVO?/reduced graphene oxide nanocomposites with higher visible light reduction activities.

    Science.gov (United States)

    Wang, Aolan; Shen, Song; Zhao, Yibo; Wu, Wei

    2015-05-01

    Bismuth vanadate/reduced graphene oxide (BiVO4/RGO) composites were synthesized by one-step hydrothermal method with graphite oxide, Bi(NO3)3 and NH4VO3 as precursors. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis spectroscopy (UV), fluorescence spectroscopy (FL) and electrochemical impedance spectroscopy (EIS). The reduced graphene oxide sheets were decorated by butterfly-like BiVO4 lamellas. Such combination not only alleviated the agglomeration of BiVO4 particles but also restrained the restacking of reduced graphene oxide. A preliminary study on the photo-reductions of Cr (VI) and CO2 under the illumination of simulated sunlight with as-synthesized BiVO4/RGO nanocomposites as catalyst was carried out. The nanocomposites showed better photo-catalytic activity than the conventional BiVO4 particles. The photo-reduction efficiency of BiVO4/RGO nanocomposites increased about 50.1% and the ethanol yield improved about 15.4 ?mol/g-cat comparing with pure BiVO4. The enhancements of the photo-catalytic activities were attributed to the effective charge transfer of photo-generated electron from BiVO4 to RGO and improved absorption performance. PMID:25643960

  15. Resistance switching of epitaxial VO2/Al2O3 heterostructure at room temperature induced by organic liquids

    Science.gov (United States)

    Yang, Mengmeng; Yang, Yuanjun; Hong, Bin; Huang, Haoliang; Hu, Sixia; Dong, Yongqi; Wang, Haibo; He, Hao; Zhao, Jiyin; Liu, Xuguang; Luo, Zhenlin; Li, Xiaoguang; Zhang, Haibin; Gao, Chen

    2015-03-01

    We studied using organic liquids (cyclohexane, n-butanol, and ethylene glycol) to modulate the transport properties at room temperature of an epitaxial VO2 film on a VO2/Al2O3 heterostructure. The resistance of the VO2 film increased when coated with cyclohexane or n-butanol, with maximum changes of 31% and 3.8%, respectively. In contrast, it decreased when coated with ethylene glycol, with a maximum change of -7.7%. In all cases, the resistance recovered to its original value after removing the organic liquid. This organic-liquid-induced reversible resistance switching suggests that VO2 films can be used as organic molecular sensors.

  16. Estimation of VO2max from the ratio between HRmax and HRrest - the Heart Rate Ratio Method

    DEFF Research Database (Denmark)

    Uth, Niels; Sørensen, Henrik; Overgaard, Kristian; Pedersen, Preben K

    2004-01-01

    The effects of training and/or ageing upon maximal oxygen uptake ( VO(2max)) and heart rate values at rest (HR(rest)) and maximal exercise (HR(max)), respectively, suggest a relationship between VO(2max) and the HR(max)-to-HR(rest) ratio which may be of use for indirect testing of VO(2max). Fick principle calculations supplemented by literature data on maximum-to-rest ratios for stroke volume and the arterio-venous O(2) difference suggest that the conversion factor between mass-specific VO(2max)...

  17. Optical, electrical and visible light-photocatalytic properties of yttrium-substituted BiVO4 nanoparticles

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Y-substituted BiVO4 nanoparticles are synthesized by hydrothermal method. • 11.3% Y-substituted BiVO4 provides lowest charge transfer resistance. • 11.3% Y-substituted BiVO4 exhibits largest photocatalytic activity. - Abstract: Yttrium-substituted (11.3 and 30.7 at.%) BiVO4 and pristine BiVO4 nanoparticles were synthesized by hydrothermal method. They were characterized by high resolution scanning electron, field emission scanning electron, transmission electron and high resolution transmission electron microscopies, powder X-ray diffraction, and energy dispersive X-ray, Raman, UV–vis diffuse reflectance, photoluminescence and solid state impedance spectroscopies. Y-substitution favors transformation of monoclinic phase of BiVO4 to tetragonal phase. High Y-substitution increases the crystallite size as well as the band gap energy and enhances charger carrier recombination. The charge transfer resistance of 11.3% Y-substituted BiVO4 is much less than those of the others. The visible light photocatalytic activity of 11.3% Y-substituted BiVO4 nanoparticles is larger than the rest. The larger photocatalytic activity of 11.3% Y-substituted BiVO4 nanoparticles has been explained in terms of mean crystallite size, recombination of photoformed electron–hole pairs and charge transfer resistance

  18. Analysis of Secure Real Time Transport Protocol on VoIP over Wireless LAN in Campus Environment

    OpenAIRE

    Mohd Nazri Ismail

    2010-01-01

    In this research, we propose to implement Secure Real Time Transport Protocol (SRTP) on VoIP services in campus environment. Today, thedeployment of VoIP in campus environment over wireless local area network (WLAN) is not considered on security during communicationbetween two parties. Therefore, this study is to analyzed SRTP performance on different VoIP codec selection over wired. We have implemented a real VoIP network in University of Kuala Lumpur (UniKL), Malaysia. We use softphone as o...

  19. Enhanced visible-light-response photocatalytic degradation of methylene blue on Fe-loaded BiVO{sub 4} photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Chala, Sinaporn [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wetchakun, Khatcharin [Program of Physics, Faculty of Science, Ubon Ratchathani Rajabhat University, Ubon Ratchathani 34000 (Thailand); Phanichphant, Sukon [Materials Science Research Centre, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Inceesungvorn, Burapat [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wetchakun, Natda, E-mail: natda_we@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-06-01

    Highlights: • Fe-loaded BiVO{sub 4} particles were prepared by hydrothermal method. • Physicochemical properties played a significant role in photocatalytic process. • All Fe-loaded BiVO{sub 4} samples showed higher photocatalytic activity than pure BiVO{sub 4}. • The Fe{sup 3+} ions may improve the separation of photogenerated electrons and holes. - Abstract: Pure BiVO{sub 4} and nominal 0.5–5.0 mol% Fe-loaded BiVO{sub 4} samples were synthesized by hydrothermal method. All samples were characterized in order to obtain the correlation between structure and photocatalytic properties by X-ray diffraction, Brunauer, Emmett and Teller, UV–vis diffuse reflectance spectrophotometry, photoluminescence spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and inductively coupled plasma-optical emission spectroscopy. The structure of all samples was single-phase monoclinic scheelite. The absorption spectrum of 5.0 mol% Fe-loaded BiVO{sub 4} shifted to the visible region, suggesting the potential application of this material as a superior visible-light driven photocatalyst in comparison with pure BiVO{sub 4}. Photocatalytic activities of all photocatalyst samples were examined by studying the degradation of methylene blue under visible light irradiation. The results clearly showed that Fe-loaded BiVO{sub 4} sample exhibited remarkably higher activity than pure BiVO{sub 4}.

  20. Estimation of VO2max from the ratio between HRmax and HRrest - the Heart Rate Ratio Method.

    OpenAIRE

    Uth, Niels; Sørensen, Henrik; Overgaard, Kristian; Pedersen, Preben K

    2008-01-01

    The effects of training and/or ageing upon maximal oxygen uptake ( VO(2max)) and heart rate values at rest (HR(rest)) and maximal exercise (HR(max)), respectively, suggest a relationship between VO(2max) and the HR(max)-to-HR(rest) ratio which may be of use for indirect testing of VO(2max). Fick principle calculations supplemented by literature data on maximum-to-rest ratios for stroke volume and the arterio-venous O(2) difference suggest that the conversion factor between mass-specific VO(2m...

  1. Consumo Máximo de Oxígeno (Vo2max) para predecir riesgos Postoperatorios en Cirugía Abdominal Electiva

    Scientific Electronic Library Online (English)

    GA, Cabezas; LM, Meleán; HE, Torrealba.

    2001-07-01

    Full Text Available Cuando el consumo máximo de oxígeno (VO2max), se encuentra por debajo de cierto valor umbral (1 l/min o menos) los riesgos de complicaciones posoperatorias aumentan en pacientes sometidos a cirugía torácica. Esta relación no ha sido bien documentada en pacientes sometidos a cirugía abdominal. Realiz [...] amos un estudio prospectivo de tipo descriptivo sobre la capacidad que tiene el VO2max para predecir complicaciones posoperatorias, en 37 pacientes con cirugía abdominal electiva en el Hospital Vargas, Caracas y lo comparamos con la escala de medición de riesgo general, ASA y el Indice multifactorial de Goldman III. A todos los pacientes se les practicó evaluación clínica pre y posoperatoria y los exámenes paraclínicos requeridos. Las complicaciones fueron definidas previamente y los datos obtenidos, de exámenes clínicos diarios y de las historias: quirúrgicas, de anestesiología y del servicio. El VO2max fue obtenido con el método indirecto escalonado de Maneroet al validado en una población latinoamericana mediante mediciones directas de VO2max y es sencillo y de bajo costo. Asigna tres cargas sucesivas de trabajo sub máximo ( Abstract in english It has been shown a relationship between maximal oxygen uptake (VO2max), and the rise of postoperative complications in thoracic surgery but that relationship has not been well studied in abdominal surgery. We undertaken a prospective, descriptive study to define the VO2max capacity to predict post [...] surgical complications in 37 patients who underwent elective abdominal surgery at the Vargas, Hospital of Caracas and we compared with the American Society of Anesthesiologists (ASA) score and with Multifactorial Goldman score. VO2max was calculated by using Manero et al. indirect method obtained from a Latinoamerican population. It is an easy and inexpensive method that requires to perform three progressive sub maximal work loads (

  2. Efeito da intensidade do exercício de corrida intermitente 30s:15s no tempo de manutenção no ou próximo do VO2max Effect of intensity of intermittent running exercise 30s:15s at the time maintenance at or near VO2max

    Directory of Open Access Journals (Sweden)

    Rafael Alves de Aguiar

    2013-03-01

    Full Text Available O presente estudo comparou o tempo mantido acima de 90% (t90VO2max e de 95% VO2max (t95VO2max em três diferentes intensidades de exercício. Após a realização de um teste incremental para determinar o VO2max, oito estudantes de educação física ativos (23 ± 3 anos executaram três sessões de exercícios intermitentes (100, 110 e 120% da velocidade do VO2max (vVO2max com razão esforço:recuperação de 30s:15s. O t95VO2max foi significantemente maior em 110%vVO2max (EI110% (218,1 ± 81,6 s quando comparado a 100%vVO2max (EI100% (91,9 ± 75,2s e a 120%vVO2max (EI120% (126,3 ± 29,4 s, porém sem diferença entre EI100% e EI120%. O t90VO2max somente apresentou diferença significante entre EI110% e EI120%. Portanto, conclui-se que durante exercício intermitente com razão 30s:15s, a intensidade de 110%vVO2max apresenta-se mais adequada para manter o VO2 próximo ou no VO2max por um tempo maior.The present study compared the time maintained above 90% (t90VO2max or 95% VO2max (t95VO2max in three different exercise intensities. After performing an incremental test to determine VO2max, eight physical education active students (23 ± 3 years performed three intermittent exercise sessions (100, 110 e 120% velocity of VO2max (vVO2max with ratio effort:recovery of 30s:15s. The t95%VO2max was significantly higher at 110%vVO2max (EI110% (218.1 ± 81.6s compared to 100% vVO2max (EI100% (91.9 ± 75.2s and 120%vVO2max (EI120% (126.3 ± 29.4s, but without differences between EI100% and EI120%. The t90%vVO2max was significantly different only between EI110% and 120%. Therefore, we conclude that during intermittent exercise with ratio 30s:15s, the intensity of 110%vVO2max appears more appropriate to maintain VO2max for a longer time.

  3. Efeito da intensidade do exercício de corrida intermitente 30s:15s no tempo de manutenção no ou próximo do VO2max / Effect of intensity of intermittent running exercise 30s:15s at the time maintenance at or near VO2max

    Scientific Electronic Library Online (English)

    Rafael Alves de, Aguiar; Jardel, Schlickmann; Tiago, Turnes; Fabrizio, Caputo.

    2013-03-01

    Full Text Available O presente estudo comparou o tempo mantido acima de 90% (t90VO2max) e de 95% VO2max (t95VO2max) em três diferentes intensidades de exercício. Após a realização de um teste incremental para determinar o VO2max, oito estudantes de educação física ativos (23 ± 3 anos) executaram três sessões de exercíc [...] ios intermitentes (100, 110 e 120% da velocidade do VO2max (vVO2max)) com razão esforço:recuperação de 30s:15s. O t95VO2max foi significantemente maior em 110%vVO2max (EI110%) (218,1 ± 81,6 s) quando comparado a 100%vVO2max (EI100%) (91,9 ± 75,2s) e a 120%vVO2max (EI120%) (126,3 ± 29,4 s), porém sem diferença entre EI100% e EI120%. O t90VO2max somente apresentou diferença significante entre EI110% e EI120%. Portanto, conclui-se que durante exercício intermitente com razão 30s:15s, a intensidade de 110%vVO2max apresenta-se mais adequada para manter o VO2 próximo ou no VO2max por um tempo maior. Abstract in english The present study compared the time maintained above 90% (t90VO2max) or 95% VO2max (t95VO2max) in three different exercise intensities. After performing an incremental test to determine VO2max, eight physical education active students (23 ± 3 years) performed three intermittent exercise sessions (10 [...] 0, 110 e 120% velocity of VO2max (vVO2max)) with ratio effort:recovery of 30s:15s. The t95%VO2max was significantly higher at 110%vVO2max (EI110%) (218.1 ± 81.6s) compared to 100% vVO2max (EI100%) (91.9 ± 75.2s) and 120%vVO2max (EI120%) (126.3 ± 29.4s), but without differences between EI100% and EI120%. The t90%vVO2max was significantly different only between EI110% and 120%. Therefore, we conclude that during intermittent exercise with ratio 30s:15s, the intensity of 110%vVO2max appears more appropriate to maintain VO2max for a longer time.

  4. VoLTE Performance in Railway Scenarios : Investigating VoLTE as a Viable Replacement for GSM-R

    DEFF Research Database (Denmark)

    Sniady, Aleksander; SØnderskov, Morten

    2015-01-01

    GSM-Railways (GSM-R) is the current standard for railway voice and data communication. GSM-R provides railway specific voice services, such as Railway Emergency Call (REC). GSM-R provides also the European Train Control System (ETCS), which offers in-cab signaling and Automatic Train Protection (ATP). Despite these features and services, GSM-R has various major shortcomings. Therefore, alternative technologies are considered to replace GSM-R and become the next generation railway mobile communication network. 3GPP Long Term Evolution (LTE) is a likely candidate for GSM-R replacement. LTE is more efficient, flexible and offers much higher capacity, which allows the railway network to provide new communication-based applications for railways. Most of the research on LTE in railways has been focused on data-based railway applications (ETCS signaling and other). Nevertheless, voice communication is still a crucial service for railways. Regardless of its advantages, LTE can only become a railway communication technology if it provides voice communication fulfilling railway requirements. This paper presents how Voice over LTE (VoLTE) can be used to build railway communication services. Examples of Railway Emergency Call and One-to-One Call are provided. Service performance, in terms of call setup times and voice transmission quality, is analyzed in simulation scenarios modelling two railway scenarios in Denmark.

  5. Tarifas de biomasa aérea para abedul (Betula pubescens Ehrh.) y roble (Quercus robur L.) en el noroeste de España / Above-ground biomass equations for birch (Betula pubescens Ehrh.) and pedunculate oak (Quercus robur L.) in north western Spain

    Scientific Electronic Library Online (English)

    Esteban, Gómez-García; Felipe, Crecente-Campo; Ulises, Diéguez-Aranda.

    Full Text Available El objetivo de este trabajo fue el desarrollo de modelos de estimación de biomasa aérea para abedul (Betula pubescens Ehrh.) y roble (Quercus robur L.) en Galicia (noroeste de España). Para ello se emplearon datos obtenidos mediante el muestreo destructivo de 50 abedules y 50 robles, en los que se o [...] btuvo el peso seco de biomasa total y por fracciones: madera del fuste, corteza del fuste, ramas mayores de 2 cm, ramas de 0,5 cm a 2 cm, ramas menores de 0,5 cm, y hojas. En un primer paso se seleccionaron los modelos que presentaban el mejor ajuste para cada fracción de biomasa arbórea considerada. Posteriormente, y para asegurar la aditividad, se realizó un ajuste simultáneo de las ecuaciones de estimación de biomasa por fracciones junto con la de biomasa total, empleando el procedimiento estadístico denominado NSUR (Nonlinear Seemingly Unrelated Regressions). También fue necesario un ajuste ponderado para corregir la existencia de heterocedasticidad. El número de condición verificó que no existían problemas graves de multicolinealidad. Al final se obtuvo, para cada especie, un sistema de siete ecuaciones de estimación de biomasa aérea para las distintas fracciones y para la biomasa total. Estas ecuaciones explicaron como mínimo 79% de la variabilidad observada, y en el caso de las ecuaciones de biomasa total 98% para abedul y 97% para roble. Se recomienda la utilización de las ecuaciones desarrolladas en este estudio en sustitución de las ecuaciones de biomasa existentes para la región. Abstract in english The aim of this study was to develop models for above-ground biomass estimation for birch (Betula pubescens Ehrh.) and pedunculate oak (Quercus robur L.) in Galicia (northwest of Spain). Data from a destructive sampling of 50 birch trees and 50 pedunculate oak trees, that provided total dry biomass [...] weight and dry biomass weight by components: wood, bark, branches over 2 cm, branches between 0,5 cm and 2 cm, branches under 2 cm, and leaves, was used. Different models were fitted for each above-ground component and the best of them was chosen in a first step. All the models were refitted simultaneously by use of Nonlinear Seemingly Unrelated Regressions (NSUR) to ensure the additivity of the biomass equations. Weighted regression was necessary to correct the heterocedasticity of residuals. Not serious problems with multicollineality were observed. Finally, a system of seven equations for the different above-ground biomass components, and for the total biomass, was obtained for each species. These equations explained at least 79% of the observed variability. For total biomass the equations explained 98% and 97% of the observed variability for birch and oak, respectively. The developed biomass equations are recommended in substitution of the existing regional biomass equations.

  6. 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)

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

    2014-02-01

    Full Text Available 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 profiles 1 and 2 showed that a high COD removal occurred

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

    Directory of Open Access Journals (Sweden)

    Mariana Gerber

    2013-10-01

    Full Text Available 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 increase Information Security insurance premiums in the near future. Due to the dynamic nature of the technology, regulatory and legislative concerns such as lawful interception of communications and privacy may also contribute to business risk. VoIP consists of both direct communications (voice conversation and indirect communications (voice mails, emails and instant messaging. Due to this dual nature, complying with regulations such as the Regulation of Interception of Communications and Provision of Communication-Related Information Act (RICA should be considered. In order to leverage value from the VoIP implementation, an executive or SME owner should look to implement the technology with knowledge of the potential risk of civil liability. This is further highlighted by the King III Report which makes the Directors and CEO of an organisation ultimately responsible for IT Governance and Information Security Governance. The report goes further to say, any new technology, such as VoIP, should comply with all South African legislation and regulations. This responsibility encourages the practice of both due care and due diligence. However, recent trends exercised by Information Security professionals, responsible for drafting Information Security policies, often neglect the regulatory requirements and choose to only implement international best practices with no considerations to the risk of civil liability. Although these best practice frameworks may inadvertently comply with existing local legislation, a chance of an oversight is a possibility. Oversights may not only result in criminal sanctions but also civil action due to losses or damages suffered by a third party. Using both the identified regulations and relevant international best practices one may attempt to ensure good Governance with regards to VoIP’s dual nature. The aim is to aid executives and SME owners in mitigating the risk of civil liability to better leverage VoIP’s value by utilizing the proposed VoIP: Civil Liability Risk Table. This should aid in the exercise of due care and due diligence when implementing VoIP as a means of conducting business communication.

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

    Directory of Open Access Journals (Sweden)

    Tian Gerber

    2013-09-01

    Full Text Available 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 increase Information Security insurance premiums in the near future. Due to the dynamic nature of the technology, regulatory and legislative concerns such as lawful interception of communications and privacy may also contribute to business risk. VoIP consists of both direct communications (voice conversation and indirect communications (voice mails, emails and instant messaging. Due to this dual nature, complying with regulations such as the Regulation of Interception of Communications and Provision of Communication-Related Information Act (RICA should be considered. In order to leverage value from the VoIP implementation, an executive or SME owner should look to implement the technology with knowledge of the potential risk of civil liability. This is further highlighted by the King III Report which makes the Directors and CEO of an organisation ultimately responsible for IT Governance and Information Security Governance.  The report goes further to say, any new technology, such as VoIP, should comply with all South African legislation and regulations. This responsibility encourages the practice of both due care and due diligence. However, recent trends exercised by Information Security professionals, responsible for drafting Information Security policies, often neglect the regulatory requirements and choose to only implement international best practices with no considerations to the risk of civil liability. Although these best practice frameworks may inadvertently comply with existing local legislation, a chance of an oversight is a possibility. Oversights may not only result in criminal sanctions but also civil action due to losses or damages suffered by a third party. Using both the identified regulations and relevant international best practices one may attempt to ensure good Governance with regards to VoIP’s dual nature. The aim is to aid executives and SME owners in mitigating the risk of civil liability to better leverage VoIP’s value by utilizing the proposed VoIP: Civil Liability Risk Table. This should aid in the exercise of due care and due diligence when implementing VoIP as a means of conducting business communication.

  9. Influência do índice de massa corpórea, porcentagem de gordura corporal e idade da menarca sobre a capacidade aeróbia (VO2 máx) de alunas do ensino fundamental / Influence of body mass index, body fat percentage and age at menarche on aerobic capacity (VO2 max) of elementary school female students

    Scientific Electronic Library Online (English)

    Tiago Leoni, Capel; Mauro, Vaisberg; Maita Poli de, Araujo; Roberta Foster Leonidas de, Paiva; Juliana de Melo Batista dos, Santos; Zsuzsanna Ilona Katalin de Jarmy-Di, Bella.

    2014-02-01

    Full Text Available OBJETIVO: Identificar e relacionar a composição corporal, baseada na porcentagem de gordura corporal e o índice de massa corpórea (IMC), e a idade da menarca, com a capacidade aeróbia, utilizando-se os valores de VO2 máximo indireto, de estudantes do segundo ciclo do ensino fundamental. MÉTODOS [...] : Foram avaliadas 197 meninas com média de idade de 13,0±1,2 anos, estudantes de duas escolas estaduais de Atibaia-SP. Para estimar a porcentagem de gordura corporal, foi realizada uma avaliação de dobras cutâneas utilizando-se o protocolo de Slaughter para meninas adolescentes. Já o índice de massa corpórea (IMC), medido em quilogramas por metro quadrado (kg/m2), seguiu as recomendações da Organização Mundial da Saúde (OMS). Para a avaliação aeróbia, foi utilizado o teste de corrida proposto por Léger, determinando o volume de oxigênio máximo de forma indireta (VO2 máx). Para a análise estatística, foi utilizada a regressão linear de Pearson, o teste t de Student e a análise multivariada. RESULTADOS: 22,3% das meninas apresentaram sobrepeso e 3,5% obesidade, de acordo com o IMC. Na amostra estudada, 140 (71,1%) adolescentes relataram a ocorrência de menarca. A média de idade da menarca foi de 12,0±1,0 anos. A média de idade de menarca para o grupo com IMC normal foi significativamente maior (12,2±0,9 anos) do que nas estudantes com sobrepeso ou obesidade (11,6±1,0 anos). A média do VO2 máx indireto foi de 39,6±3,7 mL/kg/min, variando de 30,3 a 50,5 mL/kg/min. O avanço da idade cronológica e a precocidade da menarca correlacionaram-se positivamente com os menores valores de VO2 máx. CONCLUSÕES: Meninas com maiores valores de IMC e percentual de gordura corporal apresentaram menores valores de VO2 máx. A precocidade da menarca e o avanço da idade cronológica foram os fatores mais importantes para a redução da capacidade aeróbia. A idade da menarca foi mais elevada em meninas com IMC adequado quando comparadas com as meninas com sobrepeso ou obesidade. Abstract in english PURPOSE: To identify and relate body fat percentage (skin fold measures), body mass index (BMI) and age at menarcheto aerobic capacity using the indirect VO2 maximum value (VO2 max) of girls in the second cycle of primary school. METHODS: A total of 197 girls aged 13.0±1.2 years on average, st [...] udents from two public schools in the city of Atibaia in São Paulo, were evaluated. Anthropometric evaluation of skin folds was performed using the Slaughter protocol for teenage girls, and BMI (kg/m2) was based on "Z score" (graphic of percentile) according to WHO recommendations. The Léger protocol was used to determine VO2 max. Pearson linear regression and the Student t-test were used for statistical analysis. RESULTS: 22.3% of the girls were overweight and 3.5% were obese according to the classification proposed by the WHO; 140 (71.1%) girls reported menarche. The average age at menarche was 12.0±1.0 years and was significantly higher in the group with normal BMI (12.2±0.9 years) than in the overweight or obese groups (11.6±1.0 years). The average indirect VO2 max value was 39.6±3.7 mL/kg/min, ranging from 30.3 to 50.5 mL/kg/min. The advance of chronological age and early age at menarche were positively correlated with lower VO2 max values. CONCLUSIONS: This study showed that 25.8% of the girls had aBMI value above WHO recommendations. Girls with higher BMI and higher body fat percentage had lower VO2 max. The earlier age at menarche and the advance of chronological age were the most important factors for the reduction of aerobic capacity. The ageat menarche was higher in girls with adequate BMI compared tooverweight or obese girls.

  10. VoIP attacks detection engine based on neural network

    Science.gov (United States)

    Safarik, Jakub; Slachta, Jiri

    2015-05-01

    The security is crucial for any system nowadays, especially communications. One of the most successful protocols in the field of communication over IP networks is Session Initiation Protocol. It is an open-source project used by different kinds of applications, both open-source and proprietary. High penetration and text-based principle made SIP number one target in IP telephony infrastructure, so security of SIP server is essential. To keep up with hackers and to detect potential malicious attacks, security administrator needs to monitor and evaluate SIP traffic in the network. But monitoring and following evaluation could easily overwhelm the security administrator in networks, typically in networks with a number of SIP servers, users and logically or geographically separated networks. The proposed solution lies in automatic attack detection systems. The article covers detection of VoIP attacks through a distributed network of nodes. Then the gathered data analyze aggregation server with artificial neural network. Artificial neural network means multilayer perceptron network trained with a set of collected attacks. Attack data could also be preprocessed and verified with a self-organizing map. The source data is detected by distributed network of detection nodes. Each node contains a honeypot application and traffic monitoring mechanism. Aggregation of data from each node creates an input for neural networks. The automatic classification on a centralized server with low false positive detection reduce the cost of attack detection resources. The detection system uses modular design for easy deployment in final infrastructure. The centralized server collects and process detected traffic. It also maintains all detection nodes.

  11. Wavelength-tunable infrared metamaterial by tailoring magnetic resonance condition with VO2 phase transition

    Science.gov (United States)

    Wang, Hao; Yang, Yue; Wang, Liping

    2014-09-01

    In this work, we report the design of a wavelength-tunable infrared metamaterial by tailoring magnetic resonance condition with the phase transition of vanadium dioxide (VO2). Numerical simulation based on the finite-difference time-domain method shows a broad absorption peak at the wavelength of 10.9 ?m when VO2 is a metal, but it shifts to 15.1 ?m when VO2 changes to dielectric phase below its phase transition temperature of 68 °C. The large tunability of 38.5% in the resonance wavelength stems from the different excitation conditions of magnetic resonance mediated 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 the plasmon-phonon coupling is also discussed. The results here would be beneficial for active control of thermal radiation in novel electronic, optical, and thermal devices.

  12. Size Dependent Plasmonic Effect on BiVO4 Photoanodes for Solar Water Splitting

    Science.gov (United States)

    Zhang, Liwu; Herrmann, Lars O.; Baumberg, Jeremy J.

    2015-01-01

    Plasmonic nanostructures show great promise in enhancing the solar water splitting efficiency due to their ability to confine light to extremely small volumes inside semiconductors. While size plays a critical role in the plasmonic performance of Au nanoparticles (AuNPs), its influence on plasmon-assisted water splitting is still not fully understood. This holds especially true for low band gap semiconductors, for which interband excitations occur in wavelength regions that overlap with plasmonic resonances. Here, BiVO4 films are modified with AuNPs of diameters varying from 10 to 80?nm to study the size dependence of the plasmonic effect. Plasmon resonance energy transfer (PRET) is found to be the dominant effect in enhancing the water splitting efficiency of BiVO4. “Hot electron” injection effect is weak in the case of BiVO4/AuNP. This is attributed to the interband excitation of BiVO4, which is unfavourable for the hot electrons accumulation in BiVO4 conduction band. The resonant scattering effect also contributes to the enhanced water splitting efficiency for the larger diameter AuNPs. It is also for the first time found that higher PRET effect can be achieved at larger off-normal irradiation angle. PMID:26581942

  13. Evidence for a magnetic metallic R phase in Vanadium dioxide VO2

    Science.gov (United States)

    Xing, Hui; Taheri, Payam; Zhang, Peihong; Zeng, Hao

    2015-03-01

    Vanadium dioxide VO2 has garnered extensive research interests for over decades due to its metal-insulator transition (MIT) around 340 K (Ref. 1). Much is known for the physics behind the MIT (including a correlated structural transition and the involvement of several intermediate states). On the other hand, the magnetic property across the MIT is much less known. Although there are no fundamental arguments against the possibility of forming local magnetic moments in VO2. So far, only the M2 phase has been confirmed to possess local magnetic moments. However, our temperature-dependent magnetic susceptibility measurements of VO2 show a sudden jump at the MIT that cannot be attributed to a simple Pauli susceptibility from conducting electrons. In a recent paper2, we pointed out local magnetic moments may form in the metallic R phase. The formation of local moment would naturally explain the extremely high magnetic susceptibility of VO2 above the phase transition temperature. We further discuss the magnetoresistance (MR) measured across the MIT, which shows different magnitude and field dependence in M1 and R phase, including the MR in the metallic phase suppressed to lower temperature in a VO2 electric double layer transistor device using ionic liquid as gate dielectrics. 1. F. J. Morin, Phys. Rev. Lett. 3, 34 (1959). 2. Xun Yuan et al., Phys. Rev. B 86, 235103 (2012).

  14. Muscle oxygen desaturation is related to whole body VO2 during cross-country ski skating.

    Science.gov (United States)

    Im, J; Nioka, S; Chance, B; Rundell, K W

    2001-07-01

    Previous research has demonstrated that blood flow and subsequent O2 desaturation (OD) in exercising muscle is related to the static component during exercise. In speed skating, increased OD is dissociated from whole body VO2 and heart rate (HR) when the skater increases the static component by 'sitting low'. This phenomenon was evaluated in cross-country skiers by manipulating speed and incline during treadmill roller skiing. Eight male cross-country skiers (22.4 +/- 3.2 yrs old) randomly performed constant incline- and constant speed-based protocols in which increased load was manipulated in five 4min stages by treadmill incline or speed change, respectively. A strong relationship (r = 0.83) was observed between VO2 and % OD while blood volume change (deltaBV) was minimal. Unexpectedly, no HR/ VO2 or HR/OD shifts were observed between protocols. The % OD response, in relation to blood lactate values, during submaximal exercise was very similar to that of VO2. The lack of an observed greater desaturation at higher inclines suggests that the expected static load may be attenuated by an increased contribution of poling. The strong relationship of % OD to whole body VO2 may be attributed to O2 dissociation in the capillary bed of the muscle to meet aerobic energy demand and is independent of blood flow dynamics during cross-country ski skating. PMID:11510872

  15. Room-temperature ferromagnetism properties of monoclinic VO2 (M1) nanobelts

    International Nuclear Information System (INIS)

    Highlights: • The unusual room temperature ferromagnetism of the VO2(M1) nanobelts is found in magnetic measurement. • The oxygen vacancies induce the change of Bader charge of V atom from +2.34 to +1.84 (V+4 to V+3). • The ferromagnetic nature is a result of the oxygen vacancies based on the calculations by DFT. - Abstract: The magnetic properties of monoclinic VO2(M1) nanobelts synthesized by the hydrothermal method are investigated. The VO2(M1) nanobelts exhibit ferromagnetism at room temperature, which disagrees with previous literatures. The excessive oxygen vacancies induce the ferromagnetic nature of VO2(B) nanobelts, which is attributed to the fact that the Bader charge of V atom changes from +2.34 to +1.84 (V+4 to V+3) based on the calculations by using density functional theory (DFT). The calculations indicate that oxygen vacancy may induce the presence of V3+ atom, in agreement with experimental observations. The observed ferromagnetism should be a result of oxygen vacancies in VO2(M1) nanobelts

  16. Polarized spectroscopic properties of Er3+:Ca9Y(VO4)7 crystal

    International Nuclear Information System (INIS)

    An Er3+-doped Ca9Y(VO4)7 single crystal with dimensions of Ø 27×30 mm3 was grown successfully by Czochralski method. Its spectroscopic properties were investigated in detail. The absorption spectra show weak polarization effect, the absorption cross-sections at 801 nm are 6.36×10?21 cm2 and 9.24×10?21 cm2 for ?- and ?-polarization, respectively. The emission cross sections at 1533 nm are 9.43×10?21 cm2 for ?-polarization and 13.46×10?21 cm2 for ?-polarization. The fluorescence lifetime of the 4I13/2 manifold is 3.84 ms. When the population inversion parameter ??0.2, laser emission will be realized in the tuning range of 1575 to 1615 nm for ?-polarization. The results show that Er3+:Ca9Y(VO4)7 crystal is a promising laser material for producing 1.5 ?m laser. - Highlights: • Er3+:Ca9Y(VO4)7 crystal was grown successfully by the Czochralski method. • The spectral properties of the Er3+:Ca9Y(VO4)7 crystal was investigated. • Laser emission will be realized in the tuning range of 1505–1643 nm. • The results show that Er3+:Ca9Y( VO4)7 is a promising material for 1.5 ?m laser

  17. Proactive QoS Enhancement Technique for Efficient VoIP Performance over Wireless LAN and Cognitive Radio Network

    Directory of Open Access Journals (Sweden)

    Tamal Chakraborty

    2012-12-01

    Full Text Available VoIP over Wireless LANs is greatly affected bypath-loss, RF interference and other sources of signalattenuation in addition to network congestion. The primaryfactors involved in effective real-time communication,namely delay and loss, must be within certain controlledlimits in such a scenario. Wireless LAN Access Points must,therefore, act in tune with the codecs to ensure high qualityof the ongoing VoIP sessions. Further deployment of VoIPin opportunistic communication medium like cognitiveradio network requires thorough analysis of the factorsinvolved in design and implementation of such networksalong with modifications in VoIP parameters. In this paper,the various codec parameters are analyzed with respect towireless LAN access points. Thereafter, an optimizationalgorithm is developed based on proactive strategy to keeploss and latency within tolerable limits. The proposedalgorithm is hence implemented in the SIP enabled test-bedto provide optimum Voice over IP (VoIP performance. Theproactive strategy is further applied to study VoIPperformance over cognitive radio networks. A simulationmodel is developed for VoIP transmission in cognitive radionetworks with two scenarios where the primary and thesecondary user involve in VoIP transmission respectively.For each scenario, extensive analysis of both VoIP and CRNparameters is performed and an algorithm is proposedbased on codecs and active queues to ensure highthroughput of VoIP traffic with enhanced QoS. Resultsverify significant performance improvement in VoIP callquality under both wireless LAN and cognitive radionetwork environment. Simulation and measured resultshave also been included.

  18. Controlled synthesis of T-shaped BiVO4 and enhanced visible light responsive photocatalytic activity

    International Nuclear Information System (INIS)

    A novel T-shaped BiVO4 microcrystal photocatalyst was successfully synthesized by the hydrothermal method with the aid of a structure-directing surfactant SDBS in the present study. Having received well characterization with the aid of various techniques and the results showed that the SDBS greatly changed the microstructure of BiVO4, which had a unique T shape and belonged to the monoclinic family. The fast exchange dynamics between the surfactants bound to the Bi3+ seed surface and the free VO3? in the solution significantly increase the rate of heterogeneous nucleation. In addition, the photocatalytic activity of the prepared T-shaped BiVO4 was evaluated by the degradation of Methylene Blue solution under visible light irradiation, 17% and 47% higher decolorization rates than the commercial P25 and BiVO4 synthesized without SDBS, respectively. Meanwhile, it has been found that the degradation kinetics of MB fitted the pseudo-first-order kinetics and the T-shaped BiVO4 also displayed high photocatalytic performance for metronidazole degradation. -- Graphical abstract: H2O2 molecules function as electron trapping reagent to react with e? to enhance the photocatalytic degradation efficiency of MB in the BiVO4/H2O2 system under visible light irradiation. Highlights: • T-shaped BiVO4 was synthesized using SDBS as a structure-directing surfactant. • SDBS greatly changed the microstructure of BiVO4. • The T-shaped BiVO4 had a better visible-light photocatalytic activity. • Degradation kinetics of MB by BiVO4 fitted the pseudo-first-order kinetics

  19. Morphology-dependent photocatalytic removal of NO by hierarchical BiVO{sub 4} microboats and microspheres under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Zhihui, E-mail: jennifer.ai@mail.ccnu.edu.cn [Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079 (China); Lee, Shuncheng [Department of Civil and Structural Engineering, Research Center for Environmental Technology and Management, The Hong Kong Polytechnic University, Hong Kong (China)

    2013-09-01

    In this study, hierarchical monoclinic BiVO{sub 4} three-dimensional (3D) superstructures with two kinds of morphologies, namely BiVO{sub 4} microboats and BiVO{sub 4} 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 BiVO{sub 4} superstructures could be readily controlled with reaction time, which brought different morphologies to the final product. The as-prepared BiVO{sub 4} 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 BiVO{sub 4} 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 BiVO{sub 4} 3D catalysts can respond to visible light and their optical and photocatalytic properties are relevant to their morphologies. The BiVO{sub 4} microspheres showed superior photocatalytic activity on removal of gaseous NO compared to the BiVO{sub 4} microboats. The morphology-dependent photocatalytic property of the BiVO{sub 4} superstructures is discussed. This work suggests that the synthesized BiVO{sub 4} micropheres are promising photocatalyst for environmental remediation.

  20. Biomasa de Ulva spp. (Chlorophyta) en tres localidades del malecón de La Paz, Baja California Sur, México / Biomass of Ulva spp. (Chlorophyta) in three locations along the bayfront of La Paz, Baja California Sur, México

    Scientific Electronic Library Online (English)

    Ruth N, Aguila-Ramírez; Margarita, Casas-Valdez; Claudia J, Hernández-Guerrero; Alejandro, Marín-Álvarez.

    2005-07-01

    Full Text Available Se determinó la distribución, biomasa y potencial cosechable de Ulva spp. en tres localidades del malecón de La Paz, Baja California Sur, durante 2001 y 2002. Algunas especies de este género, antes en el género Enteromorpha, tienen una buena demanda en otros países para consumo humano. Se realizó un [...] muestreo sistemático utilizando como unidad de muestreo cuadros de 25 x 25 cm colocados cada 10 m a lo largo de transectos perpendiculares a la línea de costa trazados cada 40 m. En ambos años la mayor biomasa promedio se encontró en El Palmar. La mayor biomasa de Ulva spp. se registró durante mayo de 2001 y en febrero de 2002. La biomasa promedio fue de 351 g m-2 en 2001, mientras que en 2002 fue de 537 g m-2. Los máximos valores de biomasa cosechable se encontraron en El Kiwi en ambos años. El gran incremento en substrato que se presentó en 2002 podría explicar los altos volúmenes de cosecha estimados de 115 t húmedas. Recomendamos investigar si hay mercado para esta biomasa que permita su explotación sostenida Abstract in english Distribution and standing crop of Ulva spp. were measured in three localities along the bayfront of La Paz, Baja California Sur, during 2001 and 2002. Some species of Ulva, formerly in the genus Enteromorpha, are utilized in some countries for human consumption. We utilized a systematic sampling met [...] hod, using as sampling unit a 25 x 25 cm square placed every 10 m throughout transects perpendicular to the coastline which were drawn every 40 m. In both years the greatest average biomass was found at El Palmar. The largest biomass of Ulva spp. was recorded during May 2001 and February 2002. The average biomass was 351 g m-2 in 2001 and 537 g m-2 in 2002. The maximum values of the standing crop were found at El Kiwi in both years. The great increase in substratum in 2002 may explain the large volumes of the standing crop, estimated as 115 t wet. We recommend investigation to see if there is a market for this biomass leading to its sustainable exploitation

  1. 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)

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

    2012-12-01

    Full Text Available 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.

  2. Electrochemical reduction of sodium metavanadate in an equimolar KCl-NaCl melt

    International Nuclear Information System (INIS)

    Electrochemical reduction of sodium metavanadate in an equimolar KCl-NaCl melt and the effect of acid-base properties of the environment on this process are studied by a voltammetry method on a stationary platinum electrode. It is established that the limiting current of the NaVO3 electroreduction process has a kinetic nature. The process proceeds via an auto-inhibition scheme and its rate is controlled by an acid-base reaction conjugated with an irreversible charge transfer reaction. A substantial role of cationic composition of the melt is revealed experimentally. Following acidification of the KCl-NaCl- NaVO3 melt by Mg2+ (from MgCl2), the process passes from an irreversible kinetic regime into a reversible diffusion (quasi-diffusion) process. Values of stability constants for vanadates produced with the aid of acid-base titration of divanadium pentoxide by oxygen ions in experimental conditions are presented. These values are taken into account when calculating kinetic parameters of the NaVO3 electroreduction

  3. A acurácia da determinação do VO2max e do limiar anaeróbio La exactitud en la determinacion del VO2máx y del umbral anaerobico Accuracy of VO2max and anaerobic threshold determination

    OpenAIRE

    Paulo Cesar N Granja Filho; Fernando A. M. S. Pompeu; Alair Pedro Ribeiro de Souza e Silva

    2005-01-01

    São raros estudos que tratam da acurácia de parâmetros de trocas gasosas durante o esforço, com a população brasileira. OBJETIVO: Determinar a confiabilidade do consumo máximo de oxigênio (VO2max) e do limiar anaeróbio (LAn), assim como, a objetividade do segundo (LAn) em adultos jovens saudáveis. MÉTODOS: Foram aplicados dois testes de esforço máximo, a partir dos quais dois observadores independentes determinaram o LAn através do método de inspeção visual. Os dados foram tratados por meio d...

  4. Structural and morphology comparison between m-LaVO{sub 4} and LaVO{sub 3} compounds prepared by sol-gel acrylamide polymerization and solid state reaction

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, G. [Posgrado en Ciencias Quimicas, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, 70-360, 04510 Mexico D.F. (Mexico)], E-mail: guillermo.herrera@nucleares.unam.mx; Chavira, E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 70-360, 04510 Mexico D.F. (Mexico); Jimenez-Mier, J. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 70-543, 04510 Mexico D.F. (Mexico); Ordonez, A.; Fregoso-Israel, E.; Banos, L. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 70-360, 04510 Mexico D.F. (Mexico); Bucio, E. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 70-543, 04510 Mexico D.F. (Mexico); Guzman, J. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 70-360, 04510 Mexico D.F. (Mexico); Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Instituto Politecnico Nacional 11500 Mexico D.F. (Mexico); Novelo, O.; Flores, C. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 70-360, 04510 Mexico D.F. (Mexico)

    2009-06-24

    We contrast the production of LaVO{sub 3} polycrystalline samples obtained by reduction of m-LaVO{sub 4} prepared by sol-gel acrylamide polymerization (SGAP) and solid state reaction (SSR). For SGAP the formation of m-LaVO{sub 4} occurs at 400 deg. C, for SSR at 1400 deg. C. For m-LaVO{sub 4}-SGAP we observe a homogeneous morphology with needle-shaped grains of 50 nm average size. The SSR presents a broader size distribution in the micrometer range. Both m-LaVO{sub 4} samples were reduced into LaVO{sub 3} using a Zr rod at 850 deg. C in vacuum. LaVO{sub 3}-SGAP presents a homogeneous grain distribution with an average size of 745 nm. LaVO{sub 3}-SSR has an average size of 3.45 {mu}m. The stoichiometry of all compounds was confirmed by energy dispersive X-ray spectroscopy. X-ray powder diffraction and transmission electron microscopy give crystal structures in agreement with those reported in the literature.

  5. Teste de esforço cardioplumonar na avaliação de doenças musculares

    Directory of Open Access Journals (Sweden)

    SILVA HELGA C. ALMEIDA

    1998-01-01

    Full Text Available OBJETIVO: Analisar o teste de esforço cardiopulmonar (TECP no diagnóstico de miopatias. MÉTODOS: 27 pacientes com miopatia realizaram TECP (protocolo de bicicleta em rampa, máximo, interrompido por sintoma. RESULTADOS: Pacientes distróficos e pacientes com mitocondriopatias mostraram diferenças significativas em relação aos controles para as variáveis potência do trabalho desenvolvido (watt e pico do consumo de oxigênio (VO2 máx. Pacientes com mitocondriopatias mostraram diminuição significativa do limiar anaeróbio em relação aos controles, além de elevação dos valores do quociente respiratório (QR do pico do exercício em relação aos demais grupos. CONCLUSÕES: TECP pode ser útil na avaliação evolutiva do grau de limitação física dos pacientes com miopatia. As variáveis potência do trabalho desenvolvido, VO2 máx, limiar anaeróbio e QR do pico do exercício podem sugerir o diagnóstico de miopatia e seus subtipos, excluindo quadros psicológicos.

  6. Specificity of V·O2MAX and the ventilatory threshold in free swimming and cycle ergometry: comparison between triathletes and swimmers

    OpenAIRE

    Roels, B; Schmitt, L.; Libicz, S; Bentley, D; Richalet, J; Millet, G

    2005-01-01

    Objectives: To compare maximal heart rate (HRMAX), maximal oxygen consumption (V·O2MAX), and the ventilatory threshold (VT; %V·O2MAX) during cycle ergometry and free swimming between swimmers and triathletes.

  7. From V2O5 foam to VO2(B) nanoneedles

    International Nuclear Information System (INIS)

    Nanoneedles B phase VO2 with high crystallinity was hydrothermally synthesized from the foam prepared by mixing V2O5, aniline and H2O in the mol ratio 1:1:258. The samples have been characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction and thermal analysis. Regularly sized VO2(B) nanoneedles have the following dimensions: 0.5-5 ?m in length and about 50 nm in average diameter. According to transmission electron microscopy investigations, the V2O5 crystals resulting from the foam exhibit nanoparticles sizes between 50 and 100 nm. This way of synthesis provides a new simple and elegant route to elaborate the vanadium dioxide VO2(B) nanoneedles and V2O5 nanoparticles under soft conditions

  8. 3.3 ns Nd:LuVO4 micro-type laser

    International Nuclear Information System (INIS)

    With a compact resonator, continuous-wave (cw) and Q-switched laser performances of Nd:LuVO4 crystal was investigated. The maximum cw output power was 5.19 W. The shortest pulse width, largest pulse repetition rate, and largest pulse energy were measured to be 3.3 ns, 24.8 kHz, and 92.8 ?J, respectively, by using Cr4+:YAG crystals as the saturable absorbers. To our knowledge, this is the shortest passively Q-switched pulse width with Nd:LuVO4 as the laser crystal. From the satellite pulse, the lifetime of the lower laser energy level of Nd:LuVO4 was determined to be about 20 ns

  9. Epitaxial growth and characterization of CaVO3 thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liberati, Marco; Chopdekar, R.V.; Mehta, V.; Arenholz, E.; Suzuki, Y.

    2009-01-09

    Epitaxial thin films of CaVO{sub 3} were synthesized on SrTiO{sub 3}, LaAlO{sub 3} and (La{sub 0.27}Sr{sub 0.73})(Al{sub 0.65}Ta{sub 0.35})O{sub 3} substrates by pulsed laser deposition. All CaVO{sub 3} films, independent of epitaxial strain, exhibit metallic and Pauli paramagnetic behavior as CaVO{sub 3} single crystals. X-ray absorption measurements confirmed the 4+ valence state for Vanadium ions. With prolonged air exposure, an increasing amount of V{sup 3+} is detected and is attributed to oxygen loss in the near surface region of the films.

  10. Synthesis and characterization of the new mixed oxide NbVO5

    International Nuclear Information System (INIS)

    The mixed oxide NbVO5 has been synthesized for the first time following a procedure based on sol-gel methods. The results are compared with various attempts to obtain this compound by other procedures, which appear to be unsuccessful. NbVO5 is isostructural with TaVO5, both belonging to the structural family of the monophosphate tungsten bronzes (PO2)4(WO3)2m with a value of m=2, where single MO4 tetrahedra (M=P, V) are corner sharing with M'O6 octahedra (M'=W, Nb, Ta) determining pentagonal tunnels along [010] direction. The parameters of the orthorhombic cell are: a=11.8660(4), b=5.514(1) and c=6.915(2) A. A preliminary study of its IR spectroscopic features is also reported. 25 refs.; 3 figs.; 2 tabs

  11. Room-temperature methane activation by a bimetallic oxide cluster AlVO4+

    Science.gov (United States)

    Wang, Zhe-Chen; Wu, Xiao-Nan; Zhao, Yan-Xia; Ma, Jia-Bi; Ding, Xun-Lei; He, Sheng-Gui

    2010-04-01

    Gas-phase room-temperature methane activation by various clusters draws increasing attention. In this Letter, we produce a series of bimetallic oxide clusters which contain both main-group metal aluminum atoms and transition-metal vanadium atoms. We provide solid experimental and theoretical evidence that bimetallic AlVO4+ cluster can draw a hydrogen atom from methane to produce CH 3 at room temperature. The AlVO7+ cluster which can be considered as a system formed from Al 2O 3 + AlVO4+ does not break C-H bonds of methane. The results enrich the chemistry of gas phase methane activation and provide possible molecular level mechanism to couple with heterogeneous catalysis.

  12. Tunable subwavelength hot spot of dipole nanostructure based on VO2 phase transition.

    Science.gov (United States)

    Park, Jun-Bum; Lee, Il-Min; Lee, Seung-Yeol; Kim, Kyuho; Choi, Dawoon; Song, Eui Young; Lee, Byoungho

    2013-07-01

    We propose a novel approach to generate and tune a hot spot in a dipole nanostructure of vanadium dioxide (VO2) laid on a gold (Au) substrate. By inducing a phase transition of the VO2, the spatial and spectral distributions of the hot spot generated in the feed gap of the dipole can be tuned. Our numerical simulation based on a finite-element method shows a strong intensity enhancement difference and tunability near the wavelength of 678 nm, where the hot spot shows 172-fold intensity enhancement when VO2 is in the semiconductor phase. The physical mechanisms of forming the hot spots at the two-different phases are discussed. Based on our analysis, the effects of geometric parameters in our dipole structure are investigated with an aim of enhancing the intensity and the tunability. We hope that the proposed nanostructure opens up a practical approach for the tunable near-field nano-photonic devices. PMID:23842306

  13. Negative capacitance switching via VO2 band gap engineering driven by electric field

    International Nuclear Information System (INIS)

    We report the negative capacitance behavior of an energy band gap modulation quantum well with a sandwich VO2 layer structure. The phase transition is probed by measuring its capacitance. With the help of theoretical calculations, it shows that the negative capacitance changes of the quantum well device come from VO2 band gap by continuously tuning the temperature or voltage. Experiments reveal that as the current remains small enough, joule heating can be ignored, and the insulator-metal transition of VO2 can be induced by the electric field. Our results open up possibilities for functional devices with phase transitions induced by external electric fields other than the heating or electricity-heat transition

  14. Developing VoIP Honeypots: a Preliminary Investigation into Malfeasant Activity

    Directory of Open Access Journals (Sweden)

    Craig Valli

    2010-06-01

    Full Text Available 30 years ago PABX systems were compromised by hackers wanting to make long distance calls at some other entities expense. This activity faded as telephony became cheaper and PABX systems had countermeasures installed to overcome attacks. Now the world has moved onto the provision of telephony via broadband enabled Voice over Internet Protocol (VoIP with this service now being provided as a replacement for conventional fixed wire telephony by major telecommunication providers worldwide. Due to increasing bandwidth it is possible for systems to support multiple voice connections simultaneously. The networked nature of the Internet allows for attackers of these VoIP systems to enumerate and potentially attack and compromise a wide range of vulnerable systems. This paper is an outline of preliminary research into malfeasant VoIP activity on the Internet.

  15. Dimanganese(II hydroxide vanadate, Mn2(OH[VO4

    Directory of Open Access Journals (Sweden)

    Kewen Sun

    2014-07-01

    Full Text Available Dimanganese(II hydroxide vanadate was obtained from hydrothermal reactions. The crystal structure of the title compound is isotypic with that of Zn2(OH[VO4]. Three crystallographically independent Mn2+ ions are present, one (site symmetry .m. with a distorted trigonal-bipyramidal and two (site symmetries .m. and 1 with distorted octahedral coordination spheres. These polyhedra are linked through common edges, forming a corrugated layer-type of structure extending parallel to (100. A three-dimensional framework results via additional Mn—O—V—O—Mn connectivities involving the two different tetrahedral [VO4] units (each with point-group symmetry .m.. O—H...O hydrogen bonds (one bifurcated between the OH functions (both with point-group symmetry .m. and the [VO4] units complete this arrangement.

  16. Security Analysis System to Detect Threats on a SIP VoIP Infrasctructure Elements

    Directory of Open Access Journals (Sweden)

    Jiri Vychodil

    2011-01-01

    Full Text Available SIP PBX is definitely the alpha and omega of any IP telephony infrastructure and frequently also provides other services than those related to VoIP traffic. These exchanges are, however, very often the target of attacks by external actors. The article describes a system that was developed on VSB-TU Ostrava as a testing tool to verify if the target VoIP PBX is adequately secured and protected against any real threats. The system tests the SIP element for several usually occurring attacks and it compiles evaluation of its overall security on the basis of successfully or unsuccessfully penetrations. The article describes the applications and algorithms that are used by system and the conclusion consists recommendations and guidelines to ensure effective protection against VoIP PBX threats. The system is designed as an open-source web application, thus allowing independent access and is fully extensible to other test modules.

  17. Stress-induced domain dynamics and phase transitions in epitaxially grown VO2 nanowires

    International Nuclear Information System (INIS)

    We demonstrate that surface stresses in epitaxially grown VO2 nanowires (NWs) have a strong effect on the appearance and stability of intermediate insulating M2 phases, as well as the spatial distribution of insulating and metallic domains during structural phase transitions. During the transition from an insulating M1 phase to a metallic R phase, the coexistence of insulating M1 and M2 phases with the absence of a metallic R phase was observed at atmospheric pressure. In addition, we show that, for a VO2 NW without the presence of an epitaxial interface, surface stresses dominantly lead to spatially inhomogeneous phase transitions between insulating and metallic phases. In contrast, for a VO2 NW with the presence of an epitaxial interface, the strong epitaxial interface interaction leads to additional stresses resulting in uniformly alternating insulating and metallic domains along the NW length. (paper)

  18. Atomic and electronic structures of the SrVO3-LaAlO3 interface

    Science.gov (United States)

    Chi, Miaofang; Mizoguchi, Teruyasu; Martin, Lane W.; Bradley, John P.; Ikeno, Hidekazu; Ramesh, Ramamoorthy; Tanaka, Isao; Browning, Nigel

    2011-08-01

    The atomic and electronic structures at interfaces in thin films are typically different from the bulk and are vitally important in determining the physical properties of thin films. The interface between SrVO3, chosen as a prototype for vanadium-based perovskite materials in this work, and LaAlO3 substrate is investigated by scanning transmission electron microscopy, electron energy-loss spectroscopy, and theoretical multi-electron calculations. Extra electrons have been detected on the interface layer by comparing the energy-loss near-edge structures of V-L3,2 edges to those from the film far from the interface. Monochromated EELS and theoretical calculations for SrVO3, VO2, and V2O3 support this conclusion. The extra electrons appear to originate from a change in the local bonding configuration of V at the La-O terminated substrate surface as determined by Z-contrast imaging.

  19. Observation of insulating-insulating monoclinic structural transition in macro-sized VO2 single crystals

    International Nuclear Information System (INIS)

    VO2 single crystals with unprecedented quality, exhibiting a first-order metal-insulator transition (MIT) at 67.8 C and an insulator -insulator transition (IIT) at ?49 C, are grown using a self-flux evaporation method. Using synchrotron-based X-ray microdiffraction analysis, it is shown that the IIT is related to a structural phase transition (SPT) from the monoclinic M2 phase to the M1 phase upon heating while the MIT occurs together with a SPT of M1 to the rutile R phase. All previous reports have shown that VO2 exists in the M1 phase at room temperature in contrast to the M2 phase observed in this work. We suggest that internal strain inside single crystal VO2 may generate the previously unobserved IIT and the unusual room temperature structure. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. A viability analysis of a secure VoIP and instant messaging system on a Pocket PC platform

    OpenAIRE

    Aguirre Pastor, José Vicente; Álvarez Sánchez, Rafael Ignacio; Noguera, José; Tortosa Grau, Leandro; Zamora Gómez, Antonio

    2005-01-01

    We propose a secure full-duplex VoIP and instant messaging system on a Pocket PC platform, allowing for session key transport using a public-key protocol and encrypted text or voice communication using a private-key algorithm. The full-duplex VoIP scheme presents good performance for long duration communication over LAN networks.

  1. Combustion synthesis of Eu2+ and Dy3+ activated Sr3(VO4)2 phosphor for LEDs

    Indian Academy of Sciences (India)

    Roshani Singh; S J Dhoble

    2011-06-01

    Combustion synthesis and photoluminescence (PL) characterization of Sr3(VO4)2:Eu,Dy phosphors are presented in this paper. PL emission of Sr3(VO4)2:Eu phosphor shows green broad emission band centring at 511 nm and a red sharp band at 614 nm by excitation wavelength of 342 nm. The PL emission spectrum of Sr3(VO4)2:Dy phosphor exhibits an intense blue emission peak at 479 nm, yellow broad band centring at 573 nm and red band at 644 nm by the excitation wavelength of 426 nm in near visible blue region. The excitation wavelength of Eu (342 nm) and Dy (426 nm) activated Sr3(VO4)2 phosphor are well matched with the excitation of near UV excited solid state lighting and blue chip excitation of light emitting diodes, respectively. The effect of Eu2+ and Eu3+ ions concentration on the emission intensity of Sr3(VO4)2 was also investigated. The Sr3(VO4)2:Eu is a potential green and red emitting phosphor as well as Sr3(VO4)2:Dy is blue and yellow emitting phosphor for solid state lighting i.e. white LEDs. The XRD and SEM characteristics of Sr3(VO4)2 materials was also reported in this paper.

  2. Porous FeVO4 nanorods: synthesis, characterization, and gas-sensing properties toward volatile organic compounds

    International Nuclear Information System (INIS)

    This study reports a facile hydrothermal approach for the synthesis of shape-controlled FeVO4·1.1H2O nanorods and the subsequent conversion into FeVO4 nanorods upon calcination at 500 °C for 2 h. The lengths of the synthesized FeVO4 nanorods vary from 0.7–3.5 ?m, with the widths ranging from 70–270 nm. The proposed synthesis strategy does not involve the use of surfactants and requires only a very short reaction time, which is highly beneficial for the scale-up preparation. The anions of the Fe precursor are found to directly influence the shape and composition of the resultant hydrated FeVO4 products, due to the differences in their ionic strength and their abilities to intercalate into the layered structure of FeVO4·1.1H2O. The Cl? ions are particularly useful in limiting the growth of the nanorods in the lateral direction without being strongly intercalated into the layered structure. The porous FeVO4 nanorods exhibit higher selectivity and sensitivity toward n-butanol compared to FeVO4 nanoparticles, due to the high surface area and porosity. The findings demonstrate for the first time the potential of nanosized FeVO4 as a sensor material for the detection of volatile gases

  3. The identification of defect structures for oxygen pressure dependent VO2 crystal films

    International Nuclear Information System (INIS)

    Highlights: • The defect structures of vanadium dioxide (VO2) films are investigated using positron annihilation spectroscopy for the first time. • The concentration of vanadium vacancies is not dependent on oxygen pressure for the range studied. • It is proved indirectly that at higher oxygen pressures, the most probable point defects which have an effect on the transition properties are O-interstitials in VO2 films. • The variations of oxygen pressures are more probable to cause changes of the type or concentration of oxygen related defects (such as O-interstitials or O-vacancies) and further influence the transition characters. • VO2 films prepared by pulsed laser deposition (PLD) method keep a good preferred orientation after staying in air for six months. - Abstract: The defect structures of vanadium dioxide (VO2) films prepared at different oxygen pressures have been investigated using positron annihilation spectroscopy for the first time. It is found that the concentration of vanadium vacancies is not dependent on oxygen pressure for the range studied, implying that at high oxygen pressure, the point defects which have an effect on transition properties are O-interstitials. The variations of oxygen pressures are more probable to cause changes of the type or concentration of oxygen related defects (such as O-interstitials or O-vacancies) and further influence the transition characters. No matter what kind of the defects they are, the localized point defects have a great impact on the metal-insulator phase transition (MIT) process and the corresponding influence mechanisms are discussed. In addition, the stability of the VO2 films is also studied. The present results are valuable for the achievement of VO2-based devices

  4. Synthesis of water-soluble luminescent LaVO4:Ln3+ porous nanoparticles

    International Nuclear Information System (INIS)

    Water-soluble luminescent Eu3+ and Tb3+-doped LaVO4 porous nanoparticles were synthesized by co-precipitation method. X-ray diffraction (XRD), Field emission-transmission electron microscopy (FE-TEM), energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, UV/Vis absorption, and photoluminescence spectroscopic techniques were employed to characterize the structure and morphology of as-prepared products. The results of the XRD confirm the formation of well-crystallized LaVO4 phase with a tetragonal zircon structure. The TEM images illustrate that the as-formed Eu3+ and Tb3+-doped LaVO4 nanoparticles have irregular spherical shape, hairy nanoporous structures with an average particle size 50–130 nm. These nanoparticles were well-dispersed in polar and non-polar organic solvents to form clear colloidal solutions. The colloidal solutions of Eu3+ and Tb3+-doped zircon-type LaVO4 nanoparticles show the most dominant characteristic emissions (hypersensitive transitions) of Eu3+ at 615 nm (5D0 ? 7F2) and Tb3+ at 543 nm (5D4 ? 7F5), respectively, as the result of an energy transfer from the VO43? to luminescent metal ions activators. Compared with other-shape nanocrystals, the luminescence intensity of the irregular hairy spherical porous-like nanoparticles are obviously enhanced. It therefore, suggests that we could obtain function-improved materials by tailoring the size and shape of the LaVO4:Ln3+ nanostructures that are very suitable for use in biological applications, such as protein-labeling, drug delivery, and fluorescent bioprobes.

  5. Induction of cyto-protective autophagy by paramontroseite VO2 nanocrystals

    International Nuclear Information System (INIS)

    A variety of inorganic nanomaterials have been shown to induce autophagy, a cellular degradation process critical for the maintenance of cellular homeostasis. The overwhelming majority of autophagic responses elicited by nanomaterials were detrimental to cell fate and contributed to increased cell death. A widely held view is that the inorganic nanoparticles, when encapsulated and trapped by autophagosomes, may compromise the normal autophagic process due to the inability of the cells to degrade these materials and thus they manifest a detrimental effect on the well-being of a cell. Here we show that, contrary to this notion, nano-sized paramontroseite VO2 nanocrystals (P–VO2) induced cyto-protective, rather than death-promoting, autophagy in cultured HeLa cells. P–VO2 also caused up-regulation of heme oxygenase-1 (HO-1), a cellular protein with a demonstrated role in protecting cells against death under stress situations. The autophagy inhibitor 3-methyladenine significantly inhibited HO-1 up-regulation and increased the rate of cell death in cells treated with P–VO2, while the HO-1 inhibitor protoporphyrin IX zinc (II) (ZnPP) enhanced the occurrence of cell death in the P–VO2-treated cells while having no effect on the autophagic response induced by P–VO2. On the other hand, Y2O3 nanocrystals, a control nanomaterial, induced death-promoting autophagy without affecting the level of expression of HO-1, and the pro-death effect of the autophagy induced by Y2O3. Our results represent the first report on a novel nanomaterial-induced cyto-protective autophagy, probably through up-regulation of HO-1, and may point to new possibilities for exploiting nanomaterial-induced autophagy for therapeutic applications. (paper)

  6. Influences of chemical sympathectomy, demedullation, and hindlimb suspension on the VO2max of rats

    Science.gov (United States)

    Woodman, C. R.; Stump, C. S.; Sebastian, L. A.; Tipton, C. M.

    1992-01-01

    Results from previous studies have shown that the reduction in maximal oxygen consumption (VO2max) with simulated microgravity is attenuated in chemically sympathectomized rats. To determine the contributions of the catecholamines from the adrenal medulla in this process, investigations were conducted with 65 saline injected (SAL) and chemically sympathectomized (SX) female rats that were either surgically demedullated (DM), or intact (IN). Microgravity conditions were simulated by head-down suspension (HDS) while controls were assigned to individual cages (CC). The experimental period was 14 d. The rats were tested for VO2max, treadmill run time (RT), and submaximal mechanical efficiency (ME) prior to suspension and on days 7 and 14. Saline injected rats that had intact adrenal medullas (SAL-IN) exhibited significantly reduced measures of VO2max after 7 and 14 d by 15% and 21%, respectively. No significant reduction in VO2max was observed with HDS in the SX-IN animals. Sympathectomized rats that were demedullated (SX-DM) also exhibited a significant reduction in VO2max (12%). In addition, HDS was associated with a marked and significant reduction in RT in all groups. ME for submaximal exercise was significantly reduced after HDS in SAL-IN rats but not in the SX-IN rats. SX-DM rats experienced significant reductions in ME similar in magnitude to the SAL-IN rats. These results confirm that chemical sympathectomy attenuates the expected decrease in VO2max with HDS and suggests that circulating epinephrine contributes to this response.

  7. Physiological responses to interval training sessions at velocities associated with VO2max.

    Science.gov (United States)

    Rozenek, Ralph; Funato, Kazuo; Kubo, Junjiro; Hoshikawa, Masako; Matsuo, Akifumi

    2007-02-01

    Previous research has indicated that short-duration, high-intensity work intervals performed at velocities associated with maximal oxygen uptake (vVO2max) combined with active recovery intervals may be effective in eliciting improvements in endurance performance. This study was designed to characterize selected physiological responses to short-duration (work performed at velocities corresponding to 100% of vVO2max. Twelve men participated in 3 randomized trials consisting of treadmill running using work (W)/recovery (R) intervals of 15 seconds W/15 seconds R (15/15); 30 seconds W/15 seconds R (30/15); and 60 seconds W/15 seconds R (60/15). Work intervals were performed at 100% of vVO2max, whereas R intervals were performed at 50% of vVO2max. A fourth trial consisting of continuous work (C) at 100% of vVO2max was also performed. All subjects completed the 15/15 and 30/15 trials; however, only 5 of the 12 completed the 60/15 trial. The percentage of VO2max (mean +/- SD) during 15/15 (71.6 +/- 4.2%) was significantly lower (p 0.05) existed among 30/15 (11.5 +/- 1.8 mmol x L(-1)), 60/15 (12.5 +/- 1.8 mmol x L(-1)) or C (12.1 +/- 1.8 mmol x L(-1)). High intensity, short-duration 2:1 W/R intervals appear to produce responses that may benefit both aerobic and anaerobic energy system development. A 4:1 W/R ratio may be an upper limit for individuals in the initial phases of interval training. PMID:17313282

  8. Estimated VO2max and its corresponding velocity predict performance of amateur runners

    Directory of Open Access Journals (Sweden)

    Bruno Ribeiro Ramalho Oliveira

    2012-03-01

    Full Text Available 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 objective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max, critical velocity (CV and VO2max velocity (VVO2max 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. VVO2max 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, VVO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.91±0.07, followed by VVO2max (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.

  9. Estrategias de crecimiento y distribución de biomasa en Pinus pseudostrobus bajo diferentes condiciones de competencia / Growth strategies and biomass distribution in Pinus pseudostrobus under different conditions of competition

    Scientific Electronic Library Online (English)

    Víctor H., Cambrón Sandoval; Humberto, Suzán Azpiri; J. Jesús, Vargas Hernández; Nahum M., Sánchez Vargas; Cuauhtémoc, Sáenz-Romero.

    2013-03-01

    Full Text Available La intensidad de competencia en la que se desarrollan los individuos es un factor importante en la supervivencia, producción de biomasa y estrategia del crecimiento de la planta (arquitectura), características que interaccionan con su genotipo. En el presente estudio se evaluó el efecto de niveles d [...] e competencia en 13 familias juveniles de medios hermanos de Pinus pseudostrobus Lindl., sobre su supervivencia, producción y distribución de biomasa. Se compararon las condiciones: (I) baja densidad (0.25 x 0.12 m) con múltiples familias aleatorizadas (inter-familiar), (II) alta densidad (0.12 x 0.06 m) con grupos inter-familiares, y (III) alta densidad (0.12 x 0.06 m) con parcelas monofamiliares (intra-familiar), establecidas en un ensayo de jardín común bajo un diseño de parcelas divididas con cuatro repeticiones y cuatro individuos por familia. A 10 meses de establecido el ensayo se cosecharon dos repeticiones. Se detectaron diferencias entre condiciones de competencia (P ?0.05) para todas las variables evaluadas de producción, distribución de biomasa, supervivencia y arquitectura de crecimiento. A nivel de familia se identificaron estrategias en el crecimiento de los individuos semejantes a los tres comportamientos clásicos de arquetipos (de aislamiento, de competencia y de cultivo), así como genotipos que pudieron ajustar su crecimiento en función del ambiente de competencia. Los resultados obtenidos reflejan la importancia de la selección de ambientes y de genotipos para aumentar su adaptación y productividad en los programas de mejoramiento. Abstract in english Competition intensity at which individual plants grow is an important factor in their survival, biomass production and architecture; characteristics that interact with their genotype. In this study, we evaluated the effect of different levels of competition in 13 juvenile families of Pinus pseudostr [...] obus Lindl. half-siblings in terms of plant survival, growth and biomass distribution. The conditions compared were (I) randomized multiple families (inter-family) planted at low density (0.25 x 0.12 m), (II) inter-family groups at high density (0.12 x 0.06 m), and (III) single-family parcels (intra-family) at high density (0.12 x 0.06 m), established in a common garden test under a split plot design with four replicates and four plants per replicate. At 10 months of being established, two replicates were harvested. Differences were detected between competitive conditions for all measured variables on production, biomass distribution, survival and growth architecture (P ? 0.05). At family level we identified individual growth strategies which resemble the three classic ideotypes (isolation, competition and crop), as well as genotypes that adjusted their growth depending on the competitive environment. These results reflect the importance of environmental and genotype selection in order to increase adaptation and productivity at breeding programs.

  10. Evaluación agronómica y nutricional del pasto Ryegrass Perenne Tetraploide (Lolium perenne) producido en lecherías de las zonas altas de Costa Rica. I. Producción de biomasa y fenología

    Scientific Electronic Library Online (English)

    Luis, Villalobos; Jorge Ml, Sánchez.

    2010-06-01

    Full Text Available Se evaluó la producción de biomasa y la fenología del pasto ryegrass perenne tetraploide (Lolium perenne) a lo largo de un año en muestreos bimensuales, en 4 fincas comerciales de ganado lechero ubicadas en Chicuá de Oreamuno(latitud 09°59’, longitud 83°52’, altitud 3090 msnm), provincia de Cartago. [...] La disponibilidad de materia seca pre y pos-pastoreo, el aprovechamiento por hectárea y su porcentaje de utilización promedio para todas las fincas fueron 4110, 2276 y 1833 kg.ha-1 por corte y 44,82%, respectivamente. La edad fenológica y la relación hoja: tallo promedio de las pasturas de ryegrass perenne fueron 2,84 hojas verdes por rebrote, 56:44. Asimismo, la composición promedio de la pradera fue 76,09% ryegrass, 13,76% otras gramíneas (principalmente pasto kikuyo), 6,02% trébol, 1,25% malezas y 2,88% material senescente, respectivamente. La mayor producción de biomasa durante marzo y abril puede conservarse para utilizarse durante las épocas críticas de disponibilidad de forraje o cuando por razones climatológicas se reduce el número de horas efectivas de pastoreo. La evaluación de la edad fenológica en que se pastorea el pasto ryegrass perenne, indica que las fincas en la zona de estudio utilizan estagramínea en un estado en el que sus reservas de carbohidratos se han recuperado, lo que permite obtener una producción de biomasa y valor nutricional adecuados para satisfacer las necesidades del ganado lechero de la zona. Abstract in english Agronomic and nutritional evaluation of perennial tetraploid ryegrass-based pastures (Lolium perenne) in dairy farms in the highlands of Costa Rica. I. Dry matter yield and phenology. Dry matter yield and phenology of perennial tetraploid ryegrass (Lolium perenne)-based-pastures were evaluated in 4 [...] commercial dairy farms in the district of Chicuá, Oreamuno, Cartago (latitude 09°59’, longitude 83°52’, 3090 m of altitude) every two months during a one-year period. Average pre and postgrazing dry matter availability, utilization per hectare and percentage of utilization were 4110, 2276 and 1833 kg.ha-1 per grazing cycle and 44.82%, respectively. Average phenological stage and leaf:stem ratio were 2.84 green leaves per regrowth and 56:44. Botanical composition of ryegrass-based-pastures was 76.09% ryegrass, 13.76% other grazes (mainly kikuyu grass), 6.02% clover, 1.25% weeds and 2.88% senescent material, respectively. These pastures yield a surplus of DM during March and April, which can be conserved to be fed during the months of less pasture availability. Agronomic data show that the grazing system based on the leaf stage concept is a good tool for managing ryegrassbased-pastures in the highlands of Costa Rica.

  11. Tribological properties of self-lubricating NiAl/Mo-based composites containing AgVO3 nanowires

    International Nuclear Information System (INIS)

    Silver vanadate (AgVO3) nanowires were synthesized by hydrothermal method and self-lubricating NiAl/Mo-AgVO3 composites were fabricated by powder metallurgy technique. The composition and microstructure of NiAl/Mo-based composites were characterized and the tribological properties were investigated from room temperature to 900 °C. The results showed that NiAl/Mo-based composites were consisted of nanocrystalline B2 ordered NiAl matrix, Al2O3, Mo2C, metallic Ag and vanadium oxide phase. The appearance of metallic Ag and vanadium oxide phase can be attributed to the decomposition of AgVO3 during sintering. Wear testing results confirmed that NiAl/Mo-based composites have excellent tribological properties over a wide temperature range. For example, the friction coefficient and wear rate of NiAl/Mo-based composites containing AgVO3 were significantly lower than the composites containing only metallic Mo or AgVO3 lubricant when the temperature is above 300 °C, which can be attributed to the synergistic lubricating action of metallic Mo and AgVO3 lubricants. Furthermore, Raman results indicated that the composition on the worn surface of NiAl-based composites was self-adjusted after wear testing at different temperatures. For example, Ag3VO4 and Fe3O4 lubricants were responsible for the improvement of tribological properties at 500 °C, AgVO3, Ag3VO4 and molybdate for 700 °C, and AgVO3 and molybdate for 900 °C of NiAl-based composites with the addition of metallic Mo and AgVO3. - Highlights: • NiAl/Mo-AgVO3 nanocomposites were prepared by mechanical alloying and sintering. • AgVO3 decomposed to metallic Ag and vanadium oxide during the sintering process. • NiAl/Mo-AgVO3 exhibited superior tribological properties at a board temperature range. • Phase composition on the worn surface was varied with temperatures. • Self-adjusted action was responsible for the improvement of tribological properties

  12. Tribological properties of self-lubricating NiAl/Mo-based composites containing AgVO{sub 3} nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Eryong, E-mail: ley401@163.com [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Gao, Yimin, E-mail: ymgao@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Bai, Yaping, E-mail: jingpingxue2004@163.com [State Key Laboratory for Mechanical Behavior of Materials, School of Materials Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yi, Gewen, E-mail: gwyi@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Wenzhen, E-mail: Wzwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zeng, Zhixiang, E-mail: zengzhx@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Jia, Junhong, E-mail: jhjia@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-11-15

    Silver vanadate (AgVO{sub 3}) nanowires were synthesized by hydrothermal method and self-lubricating NiAl/Mo-AgVO{sub 3} composites were fabricated by powder metallurgy technique. The composition and microstructure of NiAl/Mo-based composites were characterized and the tribological properties were investigated from room temperature to 900 °C. The results showed that NiAl/Mo-based composites were consisted of nanocrystalline B2 ordered NiAl matrix, Al{sub 2}O{sub 3}, Mo{sub 2}C, metallic Ag and vanadium oxide phase. The appearance of metallic Ag and vanadium oxide phase can be attributed to the decomposition of AgVO{sub 3} during sintering. Wear testing results confirmed that NiAl/Mo-based composites have excellent tribological properties over a wide temperature range. For example, the friction coefficient and wear rate of NiAl/Mo-based composites containing AgVO{sub 3} were significantly lower than the composites containing only metallic Mo or AgVO{sub 3} lubricant when the temperature is above 300 °C, which can be attributed to the synergistic lubricating action of metallic Mo and AgVO{sub 3} lubricants. Furthermore, Raman results indicated that the composition on the worn surface of NiAl-based composites was self-adjusted after wear testing at different temperatures. For example, Ag{sub 3}VO{sub 4} and Fe{sub 3}O{sub 4} lubricants were responsible for the improvement of tribological properties at 500 °C, AgVO{sub 3}, Ag{sub 3}VO{sub 4} and molybdate for 700 °C, and AgVO{sub 3} and molybdate for 900 °C of NiAl-based composites with the addition of metallic Mo and AgVO{sub 3}. - Highlights: • NiAl/Mo-AgVO{sub 3} nanocomposites were prepared by mechanical alloying and sintering. • AgVO{sub 3} decomposed to metallic Ag and vanadium oxide during the sintering process. • NiAl/Mo-AgVO{sub 3} exhibited superior tribological properties at a board temperature range. • Phase composition on the worn surface was varied with temperatures. • Self-adjusted action was responsible for the improvement of tribological properties.

  13. VO-compliant libraries of high resolution spectra of cool stars

    Science.gov (United States)

    Montes, D.

    2008-10-01

    In this contribution we describe a Virtual Observatory (VO) compliant version of the libraries of high resolution spectra of cool stars described by Montes et al. (1997; 1998; and 1999). Since their publication the fully reduced spectra in FITS format have been available via ftp and in the World Wide Web. However, in the VO all the spectra will be accessible using a common web interface following the standards of the International Virtual Observatory Alliance (IVOA). These libraries include F, G, K and M field stars, from dwarfs to giants. The spectral coverage is from 3800 to 10000 Å, with spectral resolution ranging from 0.09 to 3.0 Å.

  14. Hydrogen Ordering and New Polymorph of Layered Perovskite Oxyhydrides: Sr2VO4-xHx

    CERN Document Server

    Bang, Joonho; Hiraka, Haruhiro; Fujisaki, Fumika; Otomo, Toshiya; Maki, Sachiko; Yamaura, Jun-ichi; Kumai, Reiji; Murakami, Youichi; Hosono, Hideo

    2014-01-01

    Compositionally tunable vanadium oxyhydrides Sr2VO4-xHx (x = 0 - 1) without considerable anion vacancy were synthesized by high-pressure solid state reaction. The crystal structures and their properties were characterized by powder neutron diffraction, synchrotron X-ray diffraction, thermal desorption spectroscopy, and first-principles density functional theory (DFT) calculations. The hydrogen anions selectively replaced equatorial oxygen sites in the VO6 layers via statistical substitution of hydrogen in the low x region (x 0.7. Based on the DFT calculations, the degree of oxygen/hydrogen anion ordering is strongly correlated with the bonding interaction between vanadium and the ligands.

  15. QAM Resource Allocation in Mixed-Format VoD Systems

    OpenAIRE

    Daniel Vivanco; Terry Shaw; David Reed; Jiong Gong; Jim Martin

    2007-01-01

    A Quadrature Amplitude Modulation (QAM) resource allocation algorithm for Video on Demand (VoD)traffic is presented. Based on stream encoding rates and available system capacity, the proposed on-line non-mixing algorithm will select the QAM modulator that maximizes system efficiency in a VoD service group. A ...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72¿±¿4¿mL O(2) /kg/min, mean¿±¿standard deviation) underwent testing for VO(2) kinetics (3¿×¿6¿min at 298¿±¿28¿W), endurance (120¿min preload followed by a 400-kcal time trial), and repeated sprint capacity (6¿×¿20¿s sprints, recovery 100¿s) during two 6-day periods in randomized order with a daily ingestion of ei...

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

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per; Karlsson, Magnus K; Lindén, Christian; Andersen, Lars Bo; Thorsson, Ola

    2011-01-01

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

  18. VoIP Performance Analysis over IPv4 and IPv6

    Directory of Open Access Journals (Sweden)

    Monjur Ahmed

    2014-10-01

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

  19. P2P assisted streaming for low popularity VoD contents

    OpenAIRE

    Gramatikov, Sasho; Jaureguizar Núñez, Fernando; Mishkovski, Igor; Cabrera Quesada, Julian; García Santos, Narciso

    2013-01-01

    The Video on Demand (VoD) service is becoming a dominant service in the telecommunication market due to the great convenience regarding the choice of content items and their independent viewing time. However, due to its high traffic demand nature, the VoD streaming systems are faced with the problem of huge amounts of traffic generated in the core of the network, especially for serving the requests for content items that are not in the top popularity range. Therefore, we propose a peer assist...

  20. Performance Study of Objective Speech Quality Measurement for Modern Wireless-VoIP Communications

    Directory of Open Access Journals (Sweden)

    Chan Wai-Yip

    2009-01-01

    Full Text Available Wireless-VoIP communications introduce perceptual degradations that are not present with traditional VoIP communications. This paper investigates the effects of such degradations on the performance of three state-of-the-art standard objective quality measurement algorithms—PESQ, P.563, and an "extended" E-model. The comparative study suggests that measurement performance is significantly affected by acoustic background noise type and level as well as speech codec and packet loss concealment strategy. On our data, PESQ attains superior overall performance and P.563 and E-model attain comparable performance figures.

  1. Audio Codecs Performance Analysis: Implementation of VoIP over IPv6 Protocol in Campus Network

    OpenAIRE

    Mohd Nazri Ismail

    2011-01-01

    In this research, we propose an architecturalsolution to implement voice over IP services over IPv6 incampus environment network. IPv6 is considered to bethe next-generation Internet protocol. Therefore, thisstudy is to analyze the VoIP performance and measureQuality of Service (QoS) delivered by IPv6. This studyfocuses on quality of voice such as packet loss, delay timeand jitter and CPU utilization IPv6 through soft phone.VoIP experiment will involve four types of codecs such asG.711, LPC, ...

  2. Structure and property of heteroepitaxial TiO sub 2 /VO sub 2 multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Chang, H.L.M.; Gao, Y.; Zhang, T.J.; Lam, D.J.

    1992-06-01

    Various types of TiO{sub 2}/VO{sub 2} multilayer structures have been prepared on sapphire substrates by a low-pressure metal-organic chemical vapor deposition process. X-ray diffraction and transmission electron microscopy techniques were used to study the crystallinity and epitaxial relationships of the deposited films. High resolution electron microscopy was used to examine the microstructure of the overlayers and interfaces. Electrical resistivity measurements were performed to investigate the metal-semiconductor phase transition of VO{sub 2} layers in multilayer structures.

  3. Structure and property of heteroepitaxial TiO{sub 2}/VO{sub 2} multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Chang, H.L.M.; Gao, Y.; Zhang, T.J.; Lam, D.J.

    1992-06-01

    Various types of TiO{sub 2}/VO{sub 2} multilayer structures have been prepared on sapphire substrates by a low-pressure metal-organic chemical vapor deposition process. X-ray diffraction and transmission electron microscopy techniques were used to study the crystallinity and epitaxial relationships of the deposited films. High resolution electron microscopy was used to examine the microstructure of the overlayers and interfaces. Electrical resistivity measurements were performed to investigate the metal-semiconductor phase transition of VO{sub 2} layers in multilayer structures.

  4. 532 nm continuous wave mode-locked Nd:GdVO4 laser with SESAM

    International Nuclear Information System (INIS)

    We obtain continuous wave mode-locked Nd:GdVO4-KTP laser with a SESAM. This is the first report of CW mode-locked Nd:GdVO4-KTP laser with a SESAM to our knowledge. 396 mw CW mode-locked pulse is achieved at the incident power of 7.653 W, with the repetition about 95 MHz. The pulse duration is assumed to be 5.5 ps, this is the shortest green pulse of 532 nm with SESAM

  5. VO2-like thermo-optical switching effect in one-dimensional nonlinear defective photonic crystals

    Science.gov (United States)

    Zhang, Juan; Zhang, Rongjun; Wang, Yang

    2015-06-01

    A new approach to achieve VO2-like thermo-optical switching in a one-dimensional photonic crystal by the combination of thermo-optical and optical Kerr effects was proposed and numerically demonstrated in this study. The switching temperature and the hysteresis width can be tuned in a wide temperature range. Steep transition, high optical contrast, and low pumping power can be achieved at the same time. This kind of one-dimensional photonic crystal-based bistable switch will be low-cost, easy-to-fabricate, and versatile in practical applications compared with traditional VO2-type one.

  6. Impact of growth temperature on the crystal habits, forms and structures of VO2 nanocrystals

    International Nuclear Information System (INIS)

    We investigated the impact of the process temperature on the habits, forms and crystal structure of VO2 nanocrystals grown by a vapor-transport method on (0001) quartz substrates. Four distinct growth regimes were discerned: orthorhombic nanowires, sheets, hemispheres, and nanowires with a monoclinic structure. The nanostructures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). I/V characterization of individual nanowires was enabled by Ti/Au contact formation via electron beam lithography and lift-off techniques. The expected metal-insulator transition (MIT) was found in monoclinic VO2 nanowires. (orig.)

  7. An Upgrade of Network Traffic Recognition System for SIP/VoIP Traffic Recognition

    OpenAIRE

    Hou, Jiaqi

    2009-01-01

    The purpose of this project is to update the tool of Network Traffic Recognition System (NTRS) which is proprietary software of Ericsson AB and Tsinghua University, and to implement the updated tool to finish SIP/VoIP traffic recognition. Basing on the original NTRS, I analyze the traffic recognition principal of NTRS, and redesign the structure and module of the tool according to characteristics of SIP/VoIP traffic, and then finally I program to achieve the upgrade. After the final test with...

  8. Understanding VoIP Internet Telephony and the Future Voice Network

    CERN Document Server

    Flanagan, William A

    2012-01-01

    Translates technical jargon into practical business communications solutions This book takes readers from traditional voice, fax, video, and data services delivered via separate platforms to a single, unified platform delivering all of these services seamlessly via the Internet. With its clear, jargon-free explanations, the author enables all readers to better understand and assess the growing number of voice over Internet protocol (VoIP) and unified communications (UC) products and services that are available for businesses. VoIP and Unified Communications is based on the author's careful rev

  9. High field magnetisation of the frustrated one dimensional quantum antiferromagnet LiCuVO4

    OpenAIRE

    Banks, M. G.; Heidrich-Meisner, F.; Honecker, A.; Rakoto, H.; Broto, J. -M.; Kremer, R. K.

    2006-01-01

    We have investigated the high field magnetisation of the frustrated one dimensional compound LiCuVO4. In zero field, LiCuVO4 undergoes long range antiferromagnetic order at T_{N} ~ 2.5 K with a broad short range Schottky type anomaly due to one dimensional correlations in the specific heat at 32 K. Application of a magnetic field induces a rich phase diagram. An anomaly in the derivative of the magnetisation with respect to the applied magnetic field is seen at ~ 7.5 T with ...

  10. Non-exercise estimation of VO2max using the International Physical Activity Questionnaire

    OpenAIRE

    Schembre, Susan M.; Riebe, Deborah A.

    2011-01-01

    Non-exercise equations developed from self-reported physical activity can estimate maximal oxygen uptake (VO2max) as well as submaximal exercise testing. The International Physical Activity Questionnaire (IPAQ) is the most widely used and validated self-report measure of physical activity. This study aimed to develop and test a VO2max estimation equation derived from the IPAQ-Short Form (IPAQ-S). College-aged males and females (n = 80) completed the IPAQ-S and performed a maximal exercise tes...

  11. Combination of vandetanib, radiotherapy, and irinotecan in the LoVo human colorectal cancer xenograft model.

    OpenAIRE

    Wachsberger, P; Burd, R; Ryan, A; Daskalakis, C; Dicker, AP

    2009-01-01

    PURPOSE: The tumor growth kinetics of the human LoVo colorectal xenograft model was assessed in response to vandetanib, an orally available receptor tyrosine kinase inhibitor, radiotherapy (RT), or irinotecan (CPT-11), as single therapies and in combination. METHODS AND MATERIALS: LoVo cells were injected subcutaneously into the right hind limb (5 x 10(6) cells in 100 microL phosphate-buffered saline) of athymic NCR NUM mice and tumors were grown to a volume of 200-300 mm(3) before treatment....

  12. Near field thermal memory based on radiative phase bistability of VO2

    Science.gov (United States)

    Dyakov, S. A.; Dai, J.; Yan, M.; Qiu, M.

    2015-08-01

    We report the concept of a near-field memory device based on the radiative bistability effect in the system of two closely separated parallel plates of SiO2 and VO2 which exchange heat by thermal radiation in vacuum. We demonstrate that the VO2 plate, having metal-insulator transition at 340 K, has two thermodynamical steady-states. One can switch between the states using an external laser impulse. We show that due to near-field photon tunneling between the plates, the switching time is found to be only 5?ms which is several orders lower than in case of far field.

  13. Dinámica, biomasa aérea y composición florística en parcelas permanentes Reserva Nacional Tambopata, Madre de Dios, Perú / Dynamics, aboveground biomass and composition on permanent plots, Tambopata National Reserve. Madre de Dios, Peru

    Scientific Electronic Library Online (English)

    Nadir C, Pallqui; Abel, Monteagudo; Oliver L, Phillips; Gabriela, Lopez-Gonzalez; Luciano, Cruz; Washington, Galiano; Wilfredo, Chavez; Rodolfo, Vasquez.

    2014-12-01

    Full Text Available En este estudio se evaluaron los cambios en la biomasa aérea almacenada y su dinámica en el tiempo en 9 parcelas permanentes pertenecientes a la red de parcelas de RAINFOR (Red Amazónica de Inventarios Forestales) ubicadas dentro del bosque húmedo tropical de la Reserva Nacional Tambopata en la llan [...] ura Amazónica. Se tomaron datos en campo con la metodología estandarizada RAINFOR. La biomasa se estimó usando la ecuación para bosques húmedos tropicales de Chave et al. (2005). La dinámica de la biomasa se analizó separándolos por periodos inter censales a partir del año 2003 hasta el 2011. Se registraron 64 familias, 219 géneros y 531 especies. La composición florística es muy similar en todas las parcelas excepto en la parcela de pantano. Son evidentes dos grupos ligeramente distintos y aparentemente relacionados a la edad de las antiguas terrazas fluviales de la zona. La tasa de mortalidad y reclutamiento de individuos presentan valores promedio de 2.12 ± 0.52% y 1.92 ± 0.49%, respectivamente. La tasa de reemplazo es 2.02% anual. La biomasa aérea almacenada fue de 296.2 ± 33.9 t ha-1 en promedio. La dinámica de la biomasa muestra una ganancia neta total de 1.96, 1.69 y -1.23 t ha-1 para cada periodo respectivamente. Antes de la sequía de 2010 se encontró un cambio en la biomasa de 1.88 t ha-1 año-1 y post sequía fue -0.18 t ha-1 año-1 en promedio, aunque la diferencia no fue significativa. El análisis demográfico sugiere un equilibrio dinámico en las parcelas. El balance negativo de biomasa observado para el periodo 2008 - 2011 puede deberse a la sequía del 2010, donde la mitad de las parcelas monitoreadas tuvieron una disminución en las ganancias netas de la biomasa por mortalidad de individuos afectando la composición florística selectivamente. Abstract in english In this study we evaluated the floristic composition and changes in stored biomass and dynamics over time in 9 permanent plots monitored by RAINFOR (Amazon Forest Inventory Network) and located in the lowland Amazon rainforest of the Tambopata National Reserve. Data were acquired in the field using [...] the standardized methodology of RAINFOR. The biomass was estimated using the equation for tropical moist forests of Chave et al. (2005). Biomass dynamics were analyzed, in three separated periods from 2003 to 2011. 64 families, 219 genera and 531 species were recorded. The tree floristic composition is very similar in all plots except for one swamp plot, although but it is also evident that two slightly different forest communities exist in the rest of landscape, apparently related to the age of the ancient river terraces in the area. Mortality and recruitment of individuals averaged 2.12 ± 0.52% and 1.92 ± 0.49%, respectively. The turnover rate is 2.02% per year. Aboveground biomass stored in these forests averages 296.2 ± 33.9 t ha-1. The biomass dynamics show a total net gain of 1.96, 1.69 and -1.23 t ha-1 for period respectively. Prior to the drought of 2010 a change in biomass was found 1.88 t ha-1 yr-1 and post drought was -0.18 t ha-1 yr-1 on average, though the difference is not significant. Demographic analysis suggests a dynamic equilibrium in the plots. The negative balance of biomass observed for the period 2008 - 2011 may be due to the drought of 2010, in which half of the monitored plots experienced negative net biomass change due to mortality of individuals selectively affecting the floristic composition.

  14. Efecto del NaCl en plántulas de curarí (Tabebuia serratifolia en condiciones de laboratorio

    Directory of Open Access Journals (Sweden)

    Maribel Ramírez

    2014-03-01

    Full Text Available El objetivo de este trabajo fue evaluar el efecto del cloruro de sodio (NaCl durante la germinación y el desarrollo inicial de las plántulas de curarí (Tabebuia serratifolia, en condiciones de laboratorio. Las semillas se colocaron en cinco concentraciones de NaCl: 2, 4, 6, 8 y 10 dS m-1, y en agua destilada (testigo, con una conductividad eléctrica entre 0,02 y 0,04 dS m-1. Se empleó un diseño experimental completamente al azar, con cinco repeticiones, y se aplicó un análisis de varianza. Se determinó el porcentaje de germinación (PG y la tasa de germinación (TG; y se midió la longitud del tallo (LT, la longitud de la raíz (LR, el área cotiledonal (AC, la biomasa fresca (BF y la biomasa seca (BS. La concentración de NaCl mostró efectos significativos para las variables PG, TG, BS, LT, LR y AC. Se obtuvo un 79,6 % de germinación y una TG de 1,66 días, cuando las semillas se sometieron a 6 dS m-1 de NaCl. Las concentraciones de 8 y 10 dS m-1 disminuyeron significativamente el PG, la LT y el AC de las plántulas, y retardaron la TG. Se concluye que las plántulas de curarí mostraron tolerancia a la condición salina del NaCl hasta 6 dS m-1, por lo que esta especie se puede utilizar con fines agroforestales en los sistemas de producción agropecuaria, así como en la recuperación de áreas que presenten problemas moderados de salinidad.

  15. Reservas de biomasa de árboles dispersos en potreros y mitigación al cambio climático / The contribution of dispersed trees in pastures for biomass reserve and climate change mitigati

    Scientific Electronic Library Online (English)

    Mario, Chacón-León; Celia Alice, Harvey.

    2013-06-01

    Full Text Available El presente estudio tuvo como objetivo determinar la contribución de los árboles en potreros a la mitigación al cambio climático mediante la estimación de las reservas de carbono in Costa Rica y Nicaragua. Entre los años 2002 y 2003, 17 783 árboles fueron inventariados en potreros de 59 fincas ubica [...] das en zonas de bosque tropical seco, húmedo y seco con transición a húmedo. El valor promedio de las reservas de biomasa de los árboles en los potreros fue de 10,7±1,1 Mg/ha con un valor mínimo de 5,3±1 Mg/ha en Rivas y un máximo de 13,5±3,5 Mg/ha en Matiguás. Existe relación entre la biomasa arriba del suelo de los potreros con la densidad árboles y el área basal, lo que permitió desarrollar ecuaciones simples para predecir dichos cambios. El diseño de políticas que incentiven la conservación y manejo de árboles en potreros, será un aspecto clave a ser incorporado dentro de las estrategias de cambio climático de los países. Abstract in english This study aimed to explore the contribution of trees in pastures to climate change mitigation by estimating tree biomass stocks (carbon) in Costa Rica and Nicaragua. Between 2002 and 2003, 17,783 trees were inventoried in pastures of 59 farms located in areas representing three life zones: tropical [...] dry forest, tropical wet forest and transition from tropical dry to tropical wet forest. The average value of biomass stocks of trees in pastures was 10.7 ± 1.1 Mg/ha with a minimum value of 5.3 ± 1 Mg/ha in Rivas and a maximum of 13.5 ± 3.5 Mg/ha in Matiguás. There is a relationship between aboveground biomass in the pastureland, tree density and basal area, which allows the development of simple equations. The design of policies that encourage the conservation and management of trees in pastures will be a key aspect to be incorporated into national climate change strategies.

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

    Directory of Open Access Journals (Sweden)

    Pedro Antonio Núñez Ramos

    2012-12-01

    Full Text Available En los sistemas de pasturas; la productividad de la pradera puede estar influenciada por el manejo; debido a su impacto sobre los microorganismos del suelo y el reciclaje de nutrientes. El objetivo de este trabajo fue evaluar la biomasa microbiana (BM del suelo asociada al nitrógeno (BMN; carbono (BMC y la actividad ureasa (AU en una pradera permanente del sur de Chile. Entre la primavera de 2005 y el invierno de 2006 fueron evaluados dos sistemas de pastoreo: pastoreo intenso (PI; pastoreo suave (PS y un tratamiento control (C. El diseño fue en bloques al azar con tres repeticiones. En relación a los valores promedios medidos de las variables en pre y post pastoreo; se produjo un incremento en los contenidos de CB en un 21,8 y 8,6% para PI y PS; mientras que en el control fue sólo de 1,9%. Los contenidos de NB también fueron incrementados en un 16 y 19% para PI y PS; respectivamente en comparación con el control (4%. La actividad ureasa aumentó en 13 y 27% para PI y PS; respectivamente en comparación con el control (5%. El pastoreo; produce un flujo más alto de residuos orgánicos en el suelo; lo que estimula la actividad de la biomasa microbiana y; por tanto; aumentó la AU y los contenidos de CB y NB. Esto sugiere que; en los sistemas de pastoreo; se mejora la fertilidad biológica de los suelos y la disponibilidad de nutrientes.In pasture systems, management practices can affect pasture productivity differently due to their impact on soil microorganisms and nutrient cycling. The objective of this study was to evaluate the relationship between soil microbial biomass (MB nitrogen (MBN, carbon (MBC and urease activity (UA in a permanent pasture in southern Chile. Two grazing systems were evaluated between spring 2005 and winter 2006 : heavy grazing (HG, light grazing (LG and a control treatment (C. Treatments were arranged in a randomized block design with three replications. Concerning the average values of the variables measured at the beginning and at the end of grazing, there was an increase in the content of BC of 21.8 and 8.6% for HG and LG, while the control was only 1.9%. BN contents were also increased by 16 and 19% for HG and LG, respectively, compared with the control (4%. The urease activity increased by 13 and 27% for HG and LG, respectively, compared with the control (5%. Grazing produced a higher flow of organic residues in the soil, stimulating microbial biomass and therefore increasing the UA and the BC and BN content. Thus, soil biological fertility and nutrient availability s increase under grazing systems.

  17. REMOCIÓN DE PLOMO Y NÍQUEL EN SOLUCIONES ACUOSAS USANDO BIOMASAS LIGNOCELULÓSICAS: UNA REVISIÓN / REMOVAL OF LEAD AND NICKEL IN AQUEOUS SOLUTIONS USING LIGNOCELLULOSIC BIOMASS: A REVIEW

    Scientific Electronic Library Online (English)

    Edgar, Quiñones; Candelaria, Tejada; Cesar, Arcia; Víctor, Ruiz.

    2013-12-30

    Full Text Available En la presente revisión, se identifican los bioadsorbentes extraídos de biomasas residuales utilizadas en la remoción de dos metales pesados, que presenta una amplia toxicidad para el ambiente: plomo y níquel. Se evalúa la capacidad de remoción de los mismos, destacando aquellos en los que se han ob [...] tenido altos porcentajes de remoción, mostrando la cinética aplicada en estos experimentos. Se encontró, que los bioadsorbentes más usados incluyen residuos de madera, cáscaras de frutos secos, residuos de cereales y cítricos. Para la remoción de plomo (II), el bagazo de caña de azúcar, con una capacidad de remoción de 333mg/g y para el níquel (II), la corteza de Acacia, con una capacidad de remoción de 294,1mg/g, han sido los bioadsorbentes con mayor eficiencia de remoción. Se encuentra que, en la mayoría de los experimentos, la cinética del proceso de adsorción es regida por la ecuación cinética de pseudo-segundo orden. Se recomienda el diseño de plantas piloto para la remoción de iones metálicos con las biomasas que mostraron mayor capacidad de adsorción, con el fin de que estos procesos puedan ser llevados a escala industrial. Abstract in english The present review identifies bioadsorbents, extracted from residual biomass used in the removal of two highly toxic heavy metals in the environment: lead and nickel. The ability of removal was evaluated, highlighting those which showed removal, presenting the kinetics applied in these experiments. [...] The bioadsorbente used include wood waste, nut shells, grain waste and citrus. It was found that for the removal of lead(II), the sugar cane bagasse with a removal capacity of 333mg/g and for nickel (II) acacia bark with a removal capacity of 294.1mg/g, stand out. These bioadsorbents are those reported with efficient removal ability. The kinetics of the adsorption process in most of the revised experiments is governed by the rate equation of pseudo-second order. A design of a pilot plant for removal of metal ions with biomasses with high adsorption capacity is recommended in order that these processes can be carried out in an industrial scale.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rogel Ramirez, Alejandro

    2007-07-01

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

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

    Scientific Electronic Library Online (English)

    Pedro Antonio, Núñez Ramos; Alejandra Antonia, Jara Castillo; Yessica, Sandoval Sandoval; Rolando, Demanet; María De La Luz, Mora.

    2012-12-01

    Full Text Available En los sistemas de pasturas; la productividad de la pradera puede estar influenciada por el manejo; debido a su impacto sobre los microorganismos del suelo y el reciclaje de nutrientes. El objetivo de este trabajo fue evaluar la biomasa microbiana (BM) del suelo asociada al nitrógeno (BMN); carbono [...] (BMC) y la actividad ureasa (AU) en una pradera permanente del sur de Chile. Entre la primavera de 2005 y el invierno de 2006 fueron evaluados dos sistemas de pastoreo: pastoreo intenso (PI); pastoreo suave (PS) y un tratamiento control (C). El diseño fue en bloques al azar con tres repeticiones. En relación a los valores promedios medidos de las variables en pre y post pastoreo; se produjo un incremento en los contenidos de CB en un 21,8 y 8,6% para PI y PS; mientras que en el control fue sólo de 1,9%. Los contenidos de NB también fueron incrementados en un 16 y 19% para PI y PS; respectivamente en comparación con el control (4%). La actividad ureasa aumentó en 13 y 27% para PI y PS; respectivamente en comparación con el control (5%). El pastoreo; produce un flujo más alto de residuos orgánicos en el suelo; lo que estimula la actividad de la biomasa microbiana y; por tanto; aumentó la AU y los contenidos de CB y NB. Esto sugiere que; en los sistemas de pastoreo; se mejora la fertilidad biológica de los suelos y la disponibilidad de nutrientes. Abstract in english In pasture systems, management practices can affect pasture productivity differently due to their impact on soil microorganisms and nutrient cycling. The objective of this study was to evaluate the relationship between soil microbial biomass (MB) nitrogen (MBN), carbon (MBC) and urease activity (UA) [...] in a permanent pasture in southern Chile. Two grazing systems were evaluated between spring 2005 and winter 2006 : heavy grazing (HG), light grazing (LG) and a control treatment (C). Treatments were arranged in a randomized block design with three replications. Concerning the average values of the variables measured at the beginning and at the end of grazing, there was an increase in the content of BC of 21.8 and 8.6% for HG and LG, while the control was only 1.9%. BN contents were also increased by 16 and 19% for HG and LG, respectively, compared with the control (4%). The urease activity increased by 13 and 27% for HG and LG, respectively, compared with the control (5%). Grazing produced a higher flow of organic residues in the soil, stimulating microbial biomass and therefore increasing the UA and the BC and BN content. Thus, soil biological fertility and nutrient availability s increase under grazing systems.

  20. Contenido de carbono y nitrógeno de la biomasa microbiana en suelos de La Habana / Microbial biomass carbon and nitrogen content in Havana Soil

    Scientific Electronic Library Online (English)

    Luís A., Gómez-Jorrin; Amalia, Morales-Valdes; Graciela, Dueñas-Vega; Juana María, Dantin-Martínez; Nereida, Chávez-Gonzalez; Maite, Torres-Leblanch.

    2012-06-01

    Full Text Available 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 muestra [...] s 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 ?g/g de suelo y tuvieron una correlación altamente significativa con el contenido de materia orgánica del suelo. Los contenidos de N inmovilizados variaron entre 62 y 90 ?g/g de suelo y se observó también una correlación significativa 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. Abstract in english This research was carried out to calculate the microbial biomass carbon and nitrogen content in Red Ferralitic Soils from the Havana province, using the “fumigation and extraction” method. For this work soil samples were taken from four different sites (Bainoa, La Salud, Quivicán and Guanajay) with [...] different physicalchemical characteristics, including organic matter content which ranged from 2.8 and 5%. The sensibility of the methods employed was asssessed using the mean standard error as statistical parameter. The C content in soil microbial biomass ranged from 289 and 425 ?g/g of soil (289 - 425 mg/kg of soil) and had it a significant correlation by soil organic matter content. On the other hand, N content in soil microbial biomass ranged from 62 and 90 ?g/g of soil (62-90 mg/kg of soil), and had it a significant correlation by soil nitrogen content. The mean standard error of microbial C determinations ranged from 2 and 16, being slightly superior to previous reports, while the mean standard error of the microbial N determinations were among adequate limits. Finally, this methodology was adapted to laboratory conditions.

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

    Scientific Electronic Library Online (English)

    I., Acosta; M. G., Moctezuma-Zárate; C., Gutiérrez; X., Rodríguez.

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

  2. Producción diferencial de biomasa en plántulas de Nothofagus pumilio bajo gradientes de luz y humedad del suelo Differential biomass productivity of Nothofagus pumilio seedlings under light and soil moisture gradients

    OpenAIRE

    Maria Vanessa Lencinas; Guillermo Martínez Pastur; Alicia Moretto; Emilce Gallo; Carlos Busso

    2007-01-01

    Las propuestas silviculturales disminuyen la apertura del dosel, estimulando el crecimiento de las plántulas al modificar la disponibilidad de luz y humedad del suelo. La supervivencia dependerá de su adaptación a estas nuevas condiciones ambientales. El objetivo fue evaluar la producción de biomasa de plántulas bajo gradientes de luz y humedad del suelo en condiciones controladas de luz, riego y temperatura. Se emplearon plántulas de 2-3 años en macetas bajo invernáculo, estudiándose tres ni...

  3. EVALUACIÓN DEL IMPACTO DE ACTIVIDADES ANTRÓPICAS EN EL ALMACENAMIENTO DE CARBONO EN BIOMASA VEGETAL EN ECOSISTEMAS DE ALTA MONTAÑA DE COLOMBIA / IMPACT ASSESSMENT OF ANTHROPIC ACTIVITIES ON CARBON IN PLANT BIOMASS STORAGE IN COLOMBIAN HIGH SIERRA ANDEAN ECOSYSTEMS

    Scientific Electronic Library Online (English)

    Alba M., Torres G.; Enrique J., Peña S.; Orlando, Zúñiga E.; Julián A., Peña O..

    2012-06-01

    Full Text Available Se evaluó el impacto, de las actividades antrópicas, sobre el almacenamiento de carbono en la biomasa vegetal, de bosques intervenidos y no intervenidos, mediante parcelas permanentes, en los ecosistemas de páramo y bosque alto andino, en el Parque Nacional Natural Chingaza y en el Parque Nacional N [...] atural Los Nevados, de Colombia. Se midió directamente, el carbono almacenado en biomasa de pastizales de páramo de forma indirecta, en biomasa de bosques, utilizando ecuaciones calibradas (metodología no destructiva) y se modelaron, ecuaciones de regresión estadística para estimar de forma indirecta, la biomasa de arbustos de páramo. Los resultados muestran que, los bosques altos andinos más conservados, tienen el mayor contenido de carbono, el cual se reduce drásticamente, debido a la fragmentación y la tala. Por consiguiente, es muy importante conservar el bosque alto andino, en el estado más natural posible, porque éste, es el bosque que posee, una mayor reserva de carbono. Abstract in english The impact of anthropic activities on carbon storage in plant biomass was evaluated in intervened and non-intervened forests through the establishment of permanent plots in the moor and Andean high forests in the Colombian Chingaza National Natural Park and in the Snow-covered Mountais National Natu [...] ral Park. . Carbon stored in plant biomass was measured directly in moor grasslands. Indirectly it was measured in forest biomass using calibrated equations (non-destructive methodology) and statistical regression equations were modeled to estimate indirectly the moor biomass. The results show that the most preserved high Andean forests have a higher carbon content which can be reduced drastically because of fragmentation and felling. Therefore, it is very important to maintain the high Andean forest in the most natural state possible, because this is the forest with the highest carbon reserve.

  4. Differences in evaluation of three different approaches in home range sizes of red deer Cervus elaphus in Western Carpathians / Rozdiely vo vyhodnotení ve?kosti domovských okrskov jele?a lesného Cervus elaphus v Západných Karpatoch tromi rôznymi prístupmi

    Directory of Open Access Journals (Sweden)

    Adam Alfadil Mohammed Abdelrahman

    2015-03-01

    Full Text Available Cie?om tohto príspevku bolo porovna? rozdiely v aplikácií troch rôznych prístupov k vyhodnocovaniu ve?kosti domovských okrskov vybraných sam?ích jedincov jele?a lesného (Cervus elaphus v Západných Karpatoch. Výskum bol vykonaný v Kremnických vrchoch, situovaných v centrálnej ?asti Slovenska na vzorke troch jedincov sledovaných VHF (Very High Frequency rádiotelemetriou. Údaje boli vyhodnocované v rámci troch sezón (zima, leto a ruja. Na odhad ve?kosti domovských okrskov boli použité tri metódy: Minimum Convex Polygon (MCP, Kernel Home Range (KHR and Local Convex Hull (LoCoH. Sezónne rozdiely vo ve?kosti domovských okrskov boli analyzované použitím analýzy variancie (ANOVA. Výsledky poukázali na rozdiely vo ve?kosti domovských okrskov a jadrových zón v populácii jelenej zveri. Migra?ný typ jedinca mal vä?ší okrsok v porovnaní s ostatnými, tento rozdiel však nebol štatisticky významný. Metóda LoCoH s použitím malej vzorky dát významne podhodnocuje odhady ve?kosti domovských okrskov.

  5. Synthesis and characterisation of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO22+ and VO2+ chelates with N-o-hydroxyacetophenone-imine-o-aminophenol

    International Nuclear Information System (INIS)

    Potentiometric studies on Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO22+ and VO2+ chelates with N-o-hydroxyacetophenoneimine-o-aminophenol(H2AP) have been carried out using Calvin's extension of Bjerrum's method in aqueous medium (?=0.1, 0.05 and 0.01M NaClO4) at 25, 35 and 45degC. Related thermodynamic parameters, e.g., 3?Go, ?Ho and ?So have been evaluated. Magnetic, conductance and spectral data of the solid chelates have been used to characterise them. (author)

  6. Relación entre la abundancia y biomasa de fitoplancton y bacterioplancton heterotrófico en aguas superficiales del Golfo de Arauco, Chile Relation between count and biomass of phytoplankton and heterotrophic bacterioplankton in superficial water of Arauco Gulf, Chile

    Directory of Open Access Journals (Sweden)

    Mireya Abarzúa R

    1995-01-01

    Full Text Available Se analiza la relación entre la abundancia (concentración de células y biomasa fitoplanctónica con la bacteriana, en la zona adyacente a la desembocadura del río Bío-Bío en el Golfo de Arauco, Chile. Para estimar la abundancia y biomasa bacteriana total, de bacterias heterótrofas aeróbicas recuperables y del fitoplancton, se realizaron muestreos en marzo (verano y agosto (invierno de 1991. Los resultados indican que la abundancia del fitoplancton presenta una correlación significativa con la abundancia y biomasa de bacterias heterotróficas, a diferencia de lo que ocurre con las mismas variables del total de bacterias. Se encontró una alta correlación de la abundancia de algas fitoplanctónicas y bacterias heterotróficas con la temperatura, parámetro que explica un alto porcentaje de las variaciones temporales observadasThis work analize the relationships between the standing crop and biomass of phytoplankton and bacteria in the zone of the Arauco Gulf, Chile. Samples were taken during the month of march (summer and august (winter of 1991. The number and biomass of total bacteria, of aerobic heterotrophic bacteria, and of the phytoplankton were studied. The results show that the number of phytoplankton has a positive correlation with the number and biomass of the heterotrophic bacteria, but not with the total bacteria. There is also a high correlation with temperature, justifying the temporal variations noted in the results

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

    Directory of Open Access Journals (Sweden)

    J. M. Anguiano

    2013-01-01

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

  8. Registro de la dinámica témporomandibular mediante ultrasonidos con ARCUSdigma de KaVo Registry of temporomandibular dynamics by means of ultrasounds with ARCUSdigma by KaVo

    Directory of Open Access Journals (Sweden)

    A Cárdenas Martos

    2003-06-01

    Full Text Available A lo largo del tiempo se han descrito distintos métodos para conocer y registrar la dinámica mandibular. En el presente trabajo exponemos un nuevo método basado en la emisión y recepción de ultrasonidos que nos va a permitir trabajar en tiempo real con reproducciones digitales de los movimientos que hace el paciente. Este sistema, recientemente creado por la empresa alemana KaVo, puede ser una gran ayuda, no tan solo para acelerar y mejorar el montaje y ajuste de modelos en articulador, sino para conocer en el momento, y antes de enfrentarse a un trabajo de restauración, las características de los movimientos mandibulares del paciente y poder dejarlo registrado en nuestra historia. Del mismo modo, esta posibilidad de trabajar con gráficos de movimiento mandibular en tiempo real tiene, a nuestra forma de ver, infinidad de posibilidades en el área de la educación, investigación ...etc. Por tanto, el primer paso es presentar y conocer las posibilidades del ARCUSdigma® de KaVo (KaVo elektrotechnisches, Werk, GMBH, Leutkirch,Germany.Throughout the time different methods have been described to know and to register temporomandibular dynamics. In the present work we expose a new method based on the emission and reception of ultrasounds that is going to allow us to work in real time with digital reproductions of the movements that the patient does. This system, recently created by the German company KaVo, can be a great aid, not so single to accelerate and to improve the assembly and adjustment of models in artieulator, but to know in the moment, and before facing a work of restoration, the characteristics of the patient jaw movements and to leave registe red it in our history. In the same way, this possibility of working with mandibular traffic diagrams in real time has, as we think, infinity of possibilities in the area of the education, investigation ... etc. Therefore, the first step is to present and to know ARCUSdigma® (KaVo elektrotechnisches, Werk, GMBH, leutkirch,Germany possibilities.

  9. Synthesis and electroactivity of hydrated and monoclinic rutile-type nanosized VO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Rojas, D.; Baudrin, E. [Laboratoire de Reactivite et Chimie des Solides, UMR CNRS 6007, Universite de Picardie Jules Verne, 33 rue St. Leu, 80039 Amiens CEDEX (France)

    2007-07-31

    Following recent works leading to the preparation of nanosized VO{sub 2}.H{sub 2}O and monoclinic rutile-type VO{sub 2}(M), we used a similar method to evaluate the electrochemical properties vs. lithium of such divided materials. Thus, we were able to control the morphologies of the pink VO{sub 2}.H{sub 2}O particles through a control of the temperature used during the hydrothermal treatment. Moreover, a careful treatment of these phases led to the formation of rutile-like VO{sub 2}(M) with 'dandelion' morphology. While previously reported inactive as bulk material, this phase reversibly reacts with lithium with a stable capacity of 120 mA h/g for a sample prepared at 340 C. Furthermore, the study of the hydrate shows an influence of the morphology on the electrochemical properties. This work thus clearly underlines the influence of texture on the lithium insertion properties capabilities. (author)

  10. Crystal Structure and Spectroscopic Characterization of K8(VO)2O(SO4)6:

    DEFF Research Database (Denmark)

    Rasmussen, SØren Birk; Rasmussen, Rikke Christina

    2003-01-01

    Red and yellow dichroistic crystals of a vanadium(V) compound, potassium (mu-oxo, di-mu-suifato)bis(oxodisulfato-vanadate), K-8(VO)(2)O(SO4)(6), have been obtained from the ternary catalytic model melt system K2S2O7-K2SO4-V2O5. By slow cooling of the melt from 420 to 355 degreesC, crystal growth occurred, using solid V2O5 crystals present in the melt as nucleation promoter. The compound crystallizes in the monoclinic space group P2(I) with a = 13.60(9) Angstrom, b = 13.93(9) Angstrom, c = 14.05(9) Angstrom, beta = 90.286(10)degrees, and Z = 2. It contains two VO6 octahedra linked together by a mu-oxo and two mu-sulfato bridges. Furthermore, each octahedron has two monodentate sulfate ligands, making the dimeric entity coordinatively saturated. IR spectroscopy shows bands arising from V-O-V and V=O stretches as well as splitting of sulfate bands due to the different degrees of freedom present for different conformations of sulfate ligands. The coordination of vanadium in K8(VO)20(SO4)6 is discussed in relationto the reaction mechanism Of SO2 oxidation catalysis.

  11. Thermal tuning of infrared resonant absorbers based on hybrid gold-VO2 nanostructures

    International Nuclear Information System (INIS)

    Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO2) nanostructure arrays. Absorption intensity is tuned from 90% to 20% and 96% to 32% using hybrid gold-VO2 nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO2 (68?°C). Phase change materials such as VO2 deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity

  12. Rod-like nanocrystalline B-VO{sub 2}: Hydrothermal synthesis, characterization and electrochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Soltane, L. [Laboratory of Condensed Matter Chemistry, IPEIT, University of Tunis 2, Jawaher Lel Nehru 1008, B.P. 229 Montfleury (Tunisia); Sediri, F., E-mail: faouzi.sediri@ipeit.rnu.tn [Laboratory of Condensed Matter Chemistry, IPEIT, University of Tunis 2, Jawaher Lel Nehru 1008, B.P. 229 Montfleury (Tunisia); Chemistry Department, Sciences Faculty of Tunis, Tunis El Manar University, 2092 El Manar (Tunisia)

    2014-05-01

    Graphical abstract: - Highlights: • Rod-like nanocrystalline VO{sub 2}(B) was prepared by hydrothermal process. • Reaction time on the morphology has been investigated. • CV has revealed reversible redox behavior with charge–discharge cycling. • Average coulombic efficiency is upper 98%. • Energy-related applications such as cathodes in lithium batteries. - Abstract: Rod-like nanocrystalline VO{sub 2}(B) has been successfully synthesized via a simple hydrothermal process by using V{sub 2}O{sub 5} as vanadium source and 4-butylaniline H{sub 3}C–(CH{sub 2}){sub 3}–(C{sub 6}H{sub 4})–HH{sub 2} as reducing and structure directing agent. The compounds were analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and UV–visible spectroscopy. The VO{sub 2}(B) nanorods are up to several micrometers in length and about 80 nm in thickness with a large optical band gap of ?2.709 eV. Thin films of VO{sub 2}(B) nanorods deposited on ITO substrates were electrochemically characterized by cyclic voltammetry. The voltammograms show reversible redox behavior with charge–discharge cycling process corresponding to the reversible lithium intercalation/deintercalation into the crystal lattice. The average coulombic efficiency to this redox processes is upper 98% during the electrochemistry measurements.

  13. Electronic structure and bond competition in the polar magnet PbVO$_3$

    OpenAIRE

    Singh, D.J.

    2005-01-01

    Density functional electronic structure studies of tetragonal PbVO$_3$ are reported. The results show a an important role for both Pb 6$p$ - O 2$p$ and V $d$ - O $p$ bonding, with an interplay between these. This is discussed in relation to the possibility of obtaining magnetoelectric behavior.

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

    Directory of Open Access Journals (Sweden)

    Sanjay JASOLA

    2006-07-01

    Full Text Available Voice over Internet Protocol (VoIP is becoming a reality in many organizations. The potential for mobility in voice over wi-fi networks will derive demand for the technology. Wireless VoIP is poised to rival VoIP as an alternative telephony tool. Internet has been used to transport data in the form of packet. In the past, Internet did not support any kind of sophisticated quality of service (QoS mechanism. Although the type of service (TOS field in the Internet protocol (IP header has been existing and has been allowing the differentiated treatment of packets, it was never really used on a large scale. The voice is sensitive to delay and jitter so bandwidth must be guaranteed while transporting it. With the extensive use of Internet for carrying voice, there is a need to add QoS functionality in it. QoS with reference to VoIP has been discussed in the paper. Limited bandwidth and network latency are the issues which need to be considered while using wireless LAN for packetized voice data. Efforts of standards like 802.11e which will take care of these issues, have also been explored. The impact of these technologies on distance education has also been explored in the paper.

  15. Thermal tuning of infrared resonant absorbers based on hybrid gold-VO{sub 2} nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kocer, Hasan [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States); Department of Electrical Engineering, Turkish Military Academy, 06654 Ankara (Turkey); Butun, Serkan; Aydin, Koray, E-mail: aydin@northwestern.edu [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States); Banar, Berker [Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States); Department of Electrical and Electronics Engineering, Bilkent University, 06800 Bilkent, Ankara (Turkey); Wang, Kevin; Wu, Junqiao [Department of Materials Science and Engineering, University of California Berkeley, Berkeley, California 94720 (United States); Tongay, Sefaatttin [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States)

    2015-04-20

    Resonant absorbers based on plasmonic materials, metamaterials, and thin films enable spectrally selective absorption filters, where absorption is maximized at the resonance wavelength. By controlling the geometrical parameters of nano/microstructures and materials' refractive indices, resonant absorbers are designed to operate at wide range of wavelengths for applications including absorption filters, thermal emitters, thermophotovoltaic devices, and sensors. However, once resonant absorbers are fabricated, it is rather challenging to control and tune the spectral absorption response. Here, we propose and demonstrate thermally tunable infrared resonant absorbers using hybrid gold-vanadium dioxide (VO{sub 2}) nanostructure arrays. Absorption intensity is tuned from 90% to 20% and 96% to 32% using hybrid gold-VO{sub 2} nanowire and nanodisc arrays, respectively, by heating up the absorbers above the phase transition temperature of VO{sub 2} (68?°C). Phase change materials such as VO{sub 2} deliver useful means of altering optical properties as a function of temperature. Absorbers with tunable spectral response can find applications in sensor and detector applications, in which external stimulus such as heat, electrical signal, or light results in a change in the absorption spectrum and intensity.

  16. Fabrication and characterization of electrospun orthorhombic InVO4 nanofibers

    Science.gov (United States)

    Song, Lingjun; Liu, Suwen; Lu, Qifang; Zhao, Gang

    2012-02-01

    The novel orthorhombic InVO4 nanofibers have been successfully synthesized by annealing electrospun precursor fibers. Citric acid was used as a ligand for it could react with metal salts to get a transparent homogeneous precursor solution and homogeneous precursor sol for electrospining. Polyvinyl pyrrolidone (PVP, K-30) was used as a binder and a structure guide reagent because it was one kind of water-soluble polymers. It is easy to gain one-dimensional materials while the viscosity of the citrate/PVP sol was suitable. The structure, morphology and photocatalytic properties of the nanofibers were characterized by X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electron microscopy (SEM) analysis, UV-vis spectrophotometer and fluorescence spectrophotometer. The nanofibers calcined at 700 °C were orthorhombic InVO4 with a width in the range of 30-100 nm and length in micron-grade. This one-dimensional pure orthorhombic InVO4 had the higher photocatalytic activity under visible light irradiation. The photo-degradation rate of nitrobenzene aqueous solution under visible light reached 69% after 6 h. It is obvious that the orthorhombic InVO4 nanofibers have a potential application in wastewater-treatment.

  17. Fabrication and characterization of electrospun orthorhombic InVO{sub 4} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Song Lingjun [Shandong Provincial Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics, Shandong Polytechnic University, Jinan 250353 (China); Liu Suwen, E-mail: liusw@spu.edu.cn [Shandong Provincial Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics, Shandong Polytechnic University, Jinan 250353 (China); Lu Qifang; Zhao Gang [Shandong Provincial Key Laboratory of Processing and Testing Technology of Glass and Functional Ceramics, Shandong Polytechnic University, Jinan 250353 (China)

    2012-02-01

    The novel orthorhombic InVO{sub 4} nanofibers have been successfully synthesized by annealing electrospun precursor fibers. Citric acid was used as a ligand for it could react with metal salts to get a transparent homogeneous precursor solution and homogeneous precursor sol for electrospining. Polyvinyl pyrrolidone (PVP, K-30) was used as a binder and a structure guide reagent because it was one kind of water-soluble polymers. It is easy to gain one-dimensional materials while the viscosity of the citrate/PVP sol was suitable. The structure, morphology and photocatalytic properties of the nanofibers were characterized by X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electron microscopy (SEM) analysis, UV-vis spectrophotometer and fluorescence spectrophotometer. The nanofibers calcined at 700 Degree-Sign C were orthorhombic InVO{sub 4} with a width in the range of 30-100 nm and length in micron-grade. This one-dimensional pure orthorhombic InVO{sub 4} had the higher photocatalytic activity under visible light irradiation. The photo-degradation rate of nitrobenzene aqueous solution under visible light reached 69% after 6 h. It is obvious that the orthorhombic InVO{sub 4} nanofibers have a potential application in wastewater-treatment.

  18. Observatory/data centre partnerships and the VO-centric archive: The JCMT Science Archive experience

    CERN Document Server

    Economou, Frossie; Jenness, Tim; Redman, Russell O; Goliath, Sharon; Dowler, Patrick; Currie, Malcolm J; Bell, Graham S; Graves, Sarah F; Ouellette, John; Johnstone, Doug; Schade, David; Chrysostomou, Antonio

    2014-01-01

    We present, as a case study, a description of the partnership between an observatory (JCMT) and a data centre (CADC) that led to the development of the JCMT Science Archive (JSA). The JSA is a successful example of a service designed to use Virtual Observatory (VO) technologies from the start. We describe the motivation, process and lessons learned from this approach.

  19. Non-Congruence of Thermally Induced Structural and Electronic Transitions in VO2

    Energy Technology Data Exchange (ETDEWEB)

    Nag, Joyeeta [Vanderbilt University; HaglundJr., Richard F [Vanderbilt University; Payzant, E Andrew [ORNL; More, Karren Leslie [ORNL

    2012-01-01

    The multifunctional properties of vanadium dioxide (VO2) arise from coupled first-order phase transitions: an insulator-to-metal transition (IMT) and a structural phase transition (SPT) from monoclinic to tetragonal. The characteristic signatures of the IMT and SPT are the hysteresis loops that track the phase transition from nucleation to stabilization of a new phase and back. A long-standing question about the mechanism of the VO2 phase transition is whether and how the almost-simultaneous electronic and structural transitions are related. Here we report independent measurements of the IMT and SPT hystereses in epitaxial VO2 films with differing morphologies. We show that, in both cases, the hystereses are not congruent, that the structural change requires more energy to reach completion. This result is independent of nanoscale morphology, so that the non- congruence is an intrinsic property of the VO2 phase transition. Our conclusion is supported by effective-medium calculations of the dielectric function incorporating the measured volume fractions of the monoclinic and tetragonal states. The results are consistent with the existence of an monoclinic correlated metallic state in which the electron- electron correlations characteristic of the monoclinic state begin to disappear before the transition to the tetragonal structural state.

  20. Influence of temperature on thermal properties of (Sm, Eu) VO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Parveen, Atahar, E-mail: ataharparveen@gmail.com [Department of Physics, Barkatullah University, Bhopal 462026 (India); Gaur, N.K. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

    2012-09-15

    The bulk modulus and thermal properties of orthovanadates SmVO{sub 3} and EuVO{sub 3} in the temperature range 5 K{<=}T{<=}300 K have been investigated using the Modified Rigid Ion Model (MRIM) by incorporating the effect of lattice distortions. The results on the specific heat, cohesive energy, molecular force constant, the reststrahlen frequency and the Gruneisen parameter following the temperature driven structural phase transitions are presented. Our results are in fair agreement with the available experimental data. The specific heat results can further be improved by including the spin and orbital ordering contributions to the specific heat. - Highlights: Black-Right-Pointing-Pointer Bulk modulus and thermal properties of SmVO{sub 3} and EuVO{sub 3} are computed using MRIM. Black-Right-Pointing-Pointer The structural phase transitions make their thermal properties very interesting. Black-Right-Pointing-Pointer Our results on specific heat are in good agreement with the experimental data.

  1. VO auger experience with large-scale simulations on the grid.

    Czech Academy of Sciences Publication Activity Database

    Chudoba, Ji?í

    Amsterdam : EGI.eu, 2013 - (Coelho, S.). s. 18-18 ISBN 978 90 816927 2 4. [EGI Community Forum. 08.04.2013-12.04.2013, Manchester] Institutional support: RVO:68378271 Keywords : auger Virtual Organisation (VO) * EGI grid resources Subject RIV: IN - Informatics, Computer Science

  2. High-pressure polymorphs of TbVO4: A Raman and ab initio study

    International Nuclear Information System (INIS)

    Highlights: •Three phase transitions are induced in zircon-type TbVO4 at 6.7, 26.7, and 34.4 GPa. •The proposed structural sequence is zircon-scheelite-fergusonite-orthorhombic Cmca. •Scheelite phase is metaestable after decompression. •The equation of states for all phases is reported. •Compressibility is enhanced in the Cmca phase due to f-electron delocalization. -- Abstract: Raman measurements on TbVO4 show the occurrence of three pressure-induced phase transitions. The first one, an irreversible transition from the zircon to the scheelite structure, occurs beyond 6.7 GPa. In addition, two reversible transformations take place at 26.7 and 34.4 GPa. The last transition was never reported before. The experimental findings are supported by structural and lattice-dynamics calculations that helped us to identify the post-scheelite phase as a monoclinic fergusonite structure. According to the calculations, the third transition involves a symmetry increase. An orthorhombic structure is proposed for the phase found above 34.4 GPa. The results have been compared with previous studies in TbVO4 and discussed in comparison with related compounds. The calculated equations of state are reported for the different polymorphs of TbVO4. A compressibility increase is caused by the third transition. It is associated to a bond-strength decrease, which is related to a coordination increase and a delocalization of Tb f-electrons

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