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1

System Ca3(VO4)2-Na3VO4-LaVO4  

International Nuclear Information System (INIS)

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

2

Phase composition of Na3VO4-Ca3(VO4)2-Ni3(VO4)2 system  

International Nuclear Information System (INIS)

The phase composition of the system of Na3VO4-Ca3(VO4)2-Ni(VO4)2 in a subsolidus region has been studied by the X-ray phase analysis. The region of the existence of the phase of variable composition with a garnet structure containing in a cation sublattice sodium, calcium and nickel has been found. Due to the fact that no equilibrium is observed between Na3VO4 and Ni3(VO4)2, the phase diagram is characterized, along with quazibinary cross sections and regions of three-phase equilibrium, by lines of three-phase equilibrium and regions of four-phase coexistence of the components

3

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

International Nuclear Information System (INIS)

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

4

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

CERN Document Server

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

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

1997-01-01

5

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

DEFF Research Database (Denmark)

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.

Karydis, D.A.; Boghosian, S.

2002-01-01

6

Successive orbital ordering transitions in NaVO_2  

Energy Technology Data Exchange (ETDEWEB)

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.

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

7

Thermogravimetric study of the 800 degree C reaction of zirconia stabilizing oxides with SO3-NaVO3  

International Nuclear Information System (INIS)

In this paper a thermogravimetric study is made of the reaction of the zirconia stabilizing oxides, In2O3, Sc2O3, Y2O3, and MgO, with molten NaVO3 at 800 degrees C under SO3 partial pressures of 10+2 to 10- 3 Pa. The melt composition is determined by: 2NaVO3 + SO3 right-reversible V2O5 + Na2SO4. No reaction of In2O3 was found at SO3 partial pressures up to 5 x 10+1 Pa where the reaction, In2O3 + V2O5 = 2InVO4, commenced. Reaction of Sc2O3 occurred at about 5 x 10- 1 Pa of SO3 with ScVO4 formed. Reaction of Y2O3 and MgO with the NaVO3 melt began, on the other hand, at SO3 partial pressures too low to be measured (- 3 Pa). In2O3 and (Sc)2O3 are thus potentially superior to Y2O3 and MgO as stabilizers for hot corrosion resistant zirconia thermal barrier coatings. Certain other information concerning the thermochemistry of the SO3-NaVO3 system was also revealed

8

Synthesis and characterization of the crystal structure and magnetic properties of the ternary manganese vanadate NaMnVO4.  

Science.gov (United States)

A new ternary manganese vanadate, NaMnVO(4), was synthesized by solid state reaction route, and its crystal structure and magnetic properties were characterized by X-ray diffraction, magnetic susceptibility and specific heat measurements, and by density functional calculations. NaMnVO(4) crystallizes in the maricite-type structure with space group Pnma, a = 9.563(1) A, b = 6.882(1) A, c = 5.316(1) A, and Z = 4. NaMnVO(4) contains MnO(4) chains made up of edge-sharing MnO(6) octahedra, and these chains are interlinked by VO(4) tetrahedra. The magnetic susceptibility has a broad maximum at T(max) = 24 K and follows the Curie-Weiss behavior above 70 K with ? = -62 K. NaMnVO(4) undergoes a three-dimensional antiferromagnetic ordering at T(N) = 11.8 K. The spin exchanges of NaMnVO(4) are dominated by the intrachain antiferromagnetic exchange, and the interchain spin exchanges are spin-frustrated. The most probable magnetic structure of the ordered magnetic state below T(N) was predicted on the basis of the extracted spin exchanges. PMID:20731409

Ben Yahia, Hamdi; Gaudin, Etienne; Boulahya, Khalid; Darriet, Jacques; Son, Won-Joon; Whangbo, Myung-Hwan

2010-09-20

9

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)

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}.

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

10

Vanadates of calcium and strontium in the systems NaVO3-CaCl2-MaOH-H2O, NaVO3-Sr(NO3)2-NaOH-H2O  

International Nuclear Information System (INIS)

Using pH potentiometry NaVO3 interaction with NaOH in aqueous solutions in the presence of calcium or strontium salts is investigated. Solid phases are identified by chemical and X-ray phase analyses. It is stated that SrOxV2O5x4H2O, 2CaOxV2O5x2H2O, 2SrOxV2O5x1.5H2O, 3.5CaOxV2O5, 3.5SrOxV2O5 are difficultly soluble interaction products

11

AgNa(VO2F2)2: a trioxovanadium fluoride with unconventional electrochemical properties.  

Science.gov (United States)

We present structural and electrochemical analyses of a new double-wolframite compound: AgNa(VO2F2)2 or SSVOF. SSVOF is fully ordered and displays electrochemical characteristics that give insight into electrode design for energy storage beyond lithium-ion chemistries. The compound contains trioxovanadium fluoride octahedra that combine to form one-dimensional chain-like basic building units, characteristic of wolframite (NaWO4). The 1D chains are stacked to create 2D layers; the cations Ag(+) and Na(+) lie between these layers. The vanadium oxide-fluoride octahedra are ordered by the use of cations (Ag(+), Na(+)) that differ in polarizability. In the case of sodium-ion batteries, thermodynamically, the use of a sodium anode introduces a 300 mV loss in overall cell voltage as compared to a lithium anode; however, this can be counter-balanced by introduction of fluoride into the framework to raise the reduction potentials via an inductive effect. This allows sodium-ion batteries to have comparable voltages to lithium systems. With SSVOF as a baseline compound, we have identified new materials design rules for emerging sodium-ion systems that do not apply to lithium-ion systems. These strategies can be applied broadly to provide materials of interest for fundamental structural chemistry and appreciable voltages for sodium-ion electrochemistry. PMID:23796147

Donakowski, Martin D; Görne, Arno; Vaughey, John T; Poeppelmeier, Kenneth R

2013-07-01

12

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

2013-06-01

13

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

14

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

Scientific Electronic Library Online (English)

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

Leonardo, De Lucca; Sebastião Iberes Lopes, Melo.

15

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.

16

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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

2012-03-01

17

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

International Nuclear Information System (INIS)

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

18

Thermogravimetric study of the 800[degree]C reaction of zirconia stabilizing oxides with SO[sub 3]-NaVO[sub 3  

Energy Technology Data Exchange (ETDEWEB)

In this paper a thermogravimetric study is made of the reaction of the zirconia stabilizing oxides, In[sub 2]O[sub 3], Sc[sub 2]O[sub 3], Y[sub 2]O[sub 3], and MgO, with molten NaVO[sub 3] at 800[degrees]C under SO[sub 3] partial pressures of 10[sup +2] to 10[sup [minus] 3] Pa. The melt composition is determined by: 2NaVO[sub 3] + SO[sub 3] [r reversible] V[sub 2]O[sub 5] + Na[sub 2]SO[sub 4]. No reaction of In[sub 2]O[sub 3] was found at SO[sub 3] partial pressures up to 5 [times] 10[sup +1] Pa where the reaction, In[sub 2]O[sub 3] + V[sub 2]O[sub 5] = 2InVO[sub 4], commenced. Reaction of Sc[sub 2]O[sub 3] occurred at about 5 [times] 10[sup [minus] 1] Pa of SO[sub 3] with ScVO[sub 4] formed. Reaction of Y[sub 2]O[sub 3] and MgO with the NaVO[sub 3] melt began, on the other hand, at SO[sub 3] partial pressures too low to be measured ([lt]10[sup [minus] 3] Pa). In[sub 2]O[sub 3] and (Sc)[sub 2]O[sub 3] are thus potentially superior to Y[sub 2]O[sub 3] and MgO as stabilizers for hot corrosion resistant zirconia thermal barrier coatings. Certain other information concerning the thermochemistry of the SO[sub 3]-NaVO[sub 3] system was also revealed.

Jones, R.L. (Naval Research Lab., Washington, DC (United States). Chemistry Div.)

1992-10-01

19

Synthesis and crystal structure of sodium and calcium double mixed ortho-pyrovanadate of Na3Ca2(VO4)(V2O7) composition  

International Nuclear Information System (INIS)

Na3Ca2(VO4)(V2O7) double vanadate is prepared in Na2O-CaO-V2O5 system at 600 deg C. Monoclinic cell parameters are: a=23.791(4), b=8.706(2), c=10.891(2), ?=109.74(1), z=8, sp. gr. C2/c, ?calc=2.989(3) g/cm3. X-ray diffraction analysis of compound (CAD-4, ?Mo, anisotropic least square method, R=0.034, Rw=0.036) is carried out. Structure skeleton is built of V2O74--, VO43--groups and polyhedrons of three type calcium atoms, connected with them: Ca(1)O8 (tetragonal antiprism), Ca(2)O6 and Ca(3)O6 (octahedrons of different distortion degree). Sodium atoms (coordination number Na(1)6, CNNa(2)7, CNNa(3)6) occupy skeleton vacancies

20

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-06-15

 
 
 
 
21

Resonant soft x-ray emission spectroscopy of V2O3, VO2 and NaV2O5  

International Nuclear Information System (INIS)

Resonant soft X-ray emission (RSXE) spectra of V2O3, VO2 and NaV2O5 were recorded for a series of excitation energies at resonances of the V L- and O K-absorption band. The V L- and O K-emission in these vanadium oxide bands possess considerable overlap. By resonant excitation we can tune the energy to the absorption thresholds, thereby eliminating this overlap. Hereby we obtain the V 3d and O 2p projected density-of-states of the valence band. Resonant inelastic X-ray scattering (RIXS) is found to be weak in V2O3, which we explain as being due to its metallic character at room temperature. Vanadium dioxide (VO2), semiconducting at room temperature, shows considerable RIXS features only at the O K-emission band. Distinct RIXS structures are visible in the RSXE spectra of the insulator NaV2O5. In the emission spectra excited at the V L-thresholds of this ternary vanadium oxide, dexcitations of the V dxy subband at an energy loss of -1:7 eV are observed. Our observation, that RIXS is stronger for insulators than for metals, should be taken advantage of for studying insulator-to-metal transitions in vanadium compounds in the future

22

Calefaccion centralizada por biomasa, Cuéllar  

Directory of Open Access Journals (Sweden)

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

Verdú Pérez, Jesús

2001-10-01

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

Scientific Electronic Library Online (English)

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

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

2013-12-01

24

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

Scientific Electronic Library Online (English)

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

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

25

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

Fabiana Andrade, Machado; Benedito Sérgio, Denadai.

26

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

International Nuclear Information System (INIS)

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

27

Programación por metas Energía alternativa mediante biomasa.  

Directory of Open Access Journals (Sweden)

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

Guerrero Casas, Flor María

2003-01-01

28

Resonant soft x-ray emission spectroscopy of V{sub 2}O{sub 3}, VO{sub 2} and NaV{sub 2}O{sub 5}  

Energy Technology Data Exchange (ETDEWEB)

Resonant soft X-ray emission (RSXE) spectra of V2O3, VO2 and NaV2O5 were recorded for a series of excitation energies at resonances of the V L- and O K-absorption band. The V L- and O K-emission in these vanadium oxide bands possess considerable overlap. By resonant excitation we can tune the energy to the absorption thresholds, thereby eliminating this overlap. Hereby we obtain the V 3d and O 2p projected density-of-states of the valence band. Resonant inelastic X-ray scattering (RIXS) is found to be weak in V2O3, which we explain as being due to its metallic character at room temperature. Vanadium dioxide (VO2), semiconducting at room temperature, shows considerable RIXS features only at the O K-emission band. Distinct RIXS structures are visible in the RSXE spectra of the insulator NaV2O5. In the emission spectra excited at the V L-thresholds of this ternary vanadium oxide, dexcitations of the V dxy subband at an energy loss of -1:7 eV are observed. Our observation, that RIXS is stronger for insulators than for metals, should be taken advantage of for studying insulator-to-metal transitions in vanadium compounds in the future.

Schmitt, T.; Duda, L.-C.; Augustsson, A.; Guo, J.-H.; Nordgren, J.; Downes, J.E.; McGuinness, C.; Smith, K.E.; Dhalenne, G.; Revcolevschi, A.; Klemm, M.; Horn, S.

2004-03-03

29

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)

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

FEITERA, Carlos Henrique

2006-05-01

30

PRETRATAMIENTOS DE LA CELULOSA Y BIOMASA PARA LA SACARIFICACIÓN  

Directory of Open Access Journals (Sweden)

Full Text Available La biomasa celulósica se ha vuelto un producto interesante para ser aprovechada como materia prima en la fabricación de biocombustibles, especialmente el etanol. El paso crítico en su conversión a etanol, implica la degradación de los polisacáridos a azúcares fermentables, en un proceso denominado sacarificación. La celulosa, el componente principal de la biomasa, es un polisacárido de difícil degradación en condiciones de tratamiento moderadas. Las investigaciones más recientes en el campo de los biorecursos, se han enfocado hacia el desarrollo de ciertos pretratamientos de la biomasa o la celulosa bajo los cuales se logra que estos materiales sean de más fácil degradación a azúcares fermentables. El presente artículo resume los resultados más sobresalientes, sin ser exhaustivos, de los pretaratimentos de la celulosa y la biomasa para su conversión a productos fermentables por la ruta etanólica.

ANDERSON GUARNIZO FRANCO

2009-01-01

31

Evaluación de la biomasa como recurso energético renovable en Cataluña  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Marti?nez Lozano, Sergio

2009-01-01

32

Degradación enzimática de la biomasa del Onopordum nervosumBois  

Digital Repository Infrastructure Vision for European Research (DRIVER)

En el presente trabajo se estudia la hidrolisis enzimatica de la celulosa de Onopodrum nervosum Boiss, utilizando un complejo enzimatico obtenido a partir de Trichoderma longibrachiatum QM9414. Se ha evaluado la efectividad de distintos pretratamientos (quimicos, fisicos y biologicos) sobr el rendimiento de la hidrolisis de la biomasa de O. nervosum. Este estudio ha incluido tanto el seguimiento de las alteraciones que experimentan los distintos componentes mayoritarios de la biomasa lignocel...

Negro A?lvarez, Mari?a Jose?

1991-01-01

33

PRETRATAMIENTOS DE LA CELULOSA Y BIOMASA PARA LA SACARIFICACIÓN  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La biomasa celulósica se ha vuelto un producto interesante para ser aprovechada como materia prima en la fabricación de biocombustibles, especialmente el etanol. El paso crítico en su conversión a etanol, implica la degradación de los polisacáridos a azúcares fermentables, en un proceso denominado sacarificación. La celulosa, el componente principal de la biomasa, es un polisacárido de difícil degradación en condiciones de tratamiento moderadas. Las investigaciones más recientes e...

ANDERSON GUARNIZO FRANCO; Pes, Pedro Nel Martu Cdnez Yu C.; Nchez, Hoover Albeiro Valencia Su C.

2009-01-01

34

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

Scientific Electronic Library Online (English)

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

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

2008-10-08

35

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

Directory of Open Access Journals (Sweden)

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.

Andro Pavuna

2012-05-01

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Science with VO tools: the AstroGrid VO Desktop  

Science.gov (United States)

We introduce a general range of science drivers for using the Virtual Observatory (VO) and identify some common aspects to these as well as the advantages of VO data access. We then illustrate the use of existing VO tools to tackle multi wavelength science problems. We demonstrate the ease of multi mission data access using the VOExplorer resource browser, as provided by AstroGrid (http://www.astrogrid.org) and show how to pass the various results into any VO enabled tool such as TopCat for catalogue correlation. VOExplorer offers a powerful data-centric visualisation for browsing and filtering the entire VO registry using an iTunes type interface. This allows the user to bookmark their own personalised lists of resources and to run tasks on the selected resources as desired. We introduce an example of how more advanced querying can be performed to access existing X-ray cluster of galaxies catalogues and then select extended only X-ray sources as candidate clusters of galaxies in the 2XMMi catalogue. Finally we introduce scripted access to VO resources using python with AstroGrid and demonstrate how the user can pass on the results of such a search and correlate with e.g. optical datasets such as Sloan. Hence we illustrate the power of enabling large scale data mining of multi wavelength resources in an easily reproducible way using the VO.

Tedds, J. A.

2009-07-01

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Generación eléctrica a partir de biomasa en una destilería diversificada  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Rodru Edguez, Pedro A.; Rregui, Lourdes Zumalacu E.; Geraldo Lombardi; Rez, Osney Pu E.

2007-01-01

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POTENCIALIDADES DE GENERACIÓN DE ELETRICIDAD A PARTIR DE BIOMASA  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La instalación de una destilería de etanol para la Generación de Energía Renovable Integrada a la Producción de Alimentos (GERIPA) presenta muchas ventajas en comparación con las destilerías tradicionales. La biomasa constituye una de las principales fuentes de generación de energía limpia y barata, pasando de ser un subproducto a ser una salida fundamental del proceso productivo. En el trabajo se calcula la energía disponible en el bagazo y paja de caña y de sorgo, así como en el...

OSNEY PEREZ; Zumalacarregui, Lourdes M.; ALDO OMETTO; GERALDO LOMBARDI; Rodriguez, Pedro A.

2010-01-01

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Accessing the VO with Python  

Science.gov (United States)

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

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

2014-05-01

40

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

Scientific Electronic Library Online (English)

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

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

 
 
 
 
41

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

Scientific Electronic Library Online (English)

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

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

2009-08-01

42

VO for Education: Archive Prototype  

Science.gov (United States)

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

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

2014-05-01

43

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

Scientific Electronic Library Online (English)

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

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

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Neutron diffraction studies of CeVO4,PrVO4, and ScVO4  

International Nuclear Information System (INIS)

High resolution neutron powder diffraction studies (T = 300 K) have been carried out on CeVO4, PrVO4, and ScVO4. Bond distance determinations show that although the rare earth ion size varies over a wide range, the characteristic V-O distance remains the same. The rare-earth-oxygen distances, however, approach an isotropic configuration with increasing rare earth ion size

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Neutron diffraction studies of CeVO/sub 4/,PrVO/sub 4/, and ScVO/sub 4/  

Energy Technology Data Exchange (ETDEWEB)

High resolution neutron powder diffraction studies (T = 300 K) have been carried out on CeVO/sub 4/, PrVO/sub 4/, and ScVO/sub 4/. Bond distance determinations show that although the rare earth ion size varies over a wide range, the characteristic V-O distance remains the same. The rare-earth-oxygen distances, however, approach an isotropic configuration with increasing rare earth ion size.

Faber, J. Jr.; Aldred, A.T.

1982-01-01

46

Vo?by 2012  

Directory of Open Access Journals (Sweden)

Full Text Available Vážení a milí, priatelia a priate?ky,žijeme v postmodernej dobe, v ktorej sa dá zdôvodni?, ale aj spochybni? prakticky všetko.Aj preto je nám jasné, že môžete vznies? sto argumentov proti nasej kandidatúre i proti tomu, že sme sa ocitli práve na listine tohto politického subjektu. A budete ma? svojím spôsobom pravdu. Ubezpe?ujeme Vás, že tých „100 argumentov proti“ sme zvažovali i my, ale napokon prevážilo tých 101 za. Vlastne sme mali len dve iné možnosti: nekandidova? vôbec, alebo sa pokúša? dosta? na kandidátku niektorej zo strán. Málokedy za uplynulých 22 rokov bolo u nás znechutenie politikou, sklamanie a nutkanie rezignova? silnejšie, ako práve teraz. Ale práve preto sa nám zdá, že je potrebné nerezignova? a prekona? prirodzený odpor k tomuto kroku.

MikulᚠHuba

2011-12-01

47

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

Scientific Electronic Library Online (English)

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

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

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 probablem...

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

2000-01-01

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Performance of VoIP on HSDPA  

DEFF Research Database (Denmark)

This paper provides packet scheduler design and performance simulations for running VoIP services over high-speed downlink packet access (HSDPA) in WCDMA. The main challenge of supporting VoIP service on HSDPA is the tight delay requirement combined with the small VoIP packet size. A packet scheduler design incorporating VoIP packet aggregation and user multiplexing is proposed and the VoIP capacity is studied for a macro-cellular environment. Results are obtained for different delay budgets and packet scheduling settings, using either blind round robin or a slightly modified version of proportional fair scheduling. For proportional fair scheduling with code-multiplexing of 4-users, the downlink VoIP cell capacity on HSDPA is found to be in the range 72-104 users depending on whether the delay budget for the Node-B scheduling and user reception equals 80 ms or 150 ms, respectively.

Wang, Bang; Pedersen, Klaus I.

2005-01-01

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Alonso Aguado, Antonio

2014-01-01

51

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

Directory of Open Access Journals (Sweden)

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

Anirebis Mart\\u00EDnez Romero

2014-01-01

52

Obtención de etanol a partir de biomasa lignocelulósica  

Directory of Open Access Journals (Sweden)

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

Mabel Vi\\u00F1als-Verde

2012-01-01

53

Optical Properties of Thermochromic VO2 Nanoparticles  

Science.gov (United States)

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.

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

54

A Planetary Science VO prototype  

Science.gov (United States)

The goal of the JRA4 Work Package of Europlanet-RI was to set the basis for a European Virtual Observatory in Planetary Science. The objective in this first step was to save time during searches in big archives and small databases, as well as to facilitate data access and visualization. The system is based on a new access protocol based on TAP, a specific client to query the available services, and intensive recycling of tools developed for the Astronomy VO. Some new databases were also produced in the EuroPlaNet-RI framework and are available in this context. This system should be extensible to all fields of Planetary Science, and open to external data providers.

Erard, S.; Le Sidaner, P.; Berthier, J.; Cecconi, B.; Henry, F.; Lamy, L.; Chauvin, C.; Savalle, R.; Jacquey, C.; André, N.; Schmitt, B.

2013-09-01

55

Hydrothermal Synthesis and Photocatalytic Properties of Cu-doped BiVO4 Microsheets  

Directory of Open Access Journals (Sweden)

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

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

2013-03-01

56

Comprehensive Comparison of VoIP SIP Protocol Problems and Cisco VoIP System  

Directory of Open Access Journals (Sweden)

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

TALAL AL-KHAROBI

2012-08-01

57

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

58

LACK - a VoIP Steganographic Method  

CERN Document Server

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

Mazurczyk, Wojciech

2008-01-01

59

The Armenian Virtual Observatory, ArVO  

Science.gov (United States)

The Armenian Virtual Observatory (ArVO) is a project of the Byurakan Astrophysical Observatory (BAO) aimed at construction of a modern system for astronomical data archiving, extraction, acquisition, reduction, use and publication. ArVO is based on the Digitized First Byurakan Survey (DFBS) and is the Armenian contribution to the International Virtual Observatories Alliance (IVOA). ArVO's main goal is to create an interoperability data system for Armenian astronomy based on the Armenian and world astronomy resources and according to IVOA standards. Beside the DFBS, ArVO will combine all other Byurakan archival data and modern observations from the 2.6m telescope. ArVO includes also some science projects, such as the development of an automatic identification procedure using the low-dispersion spectra and all other available databases, and optical identification of X-ray, IR and radio sources; development of an automatic search procedure for modeled objects, and automatic search for new bright AGN in the DFBS. ArVO web page is available at http://www.aras.am/arvo.htm.

Mickaelian, A. M.

2006-07-01

60

Towards a VO compliant ESO science archive  

Science.gov (United States)

Data centres have a major role in the Virtual Observatory (VO), as they are the primary source of astronomical data. The VO cannot (and does not) dictate how a data centre handles its own archive. However, ‘VO-layer’ is needed to ‘translate’ any locally defined parameter to the standard (i.e., International Virtual Observatory Alliance compliant) ones. The longer term vision of the VO is also to hide away any observatory/telescope/instrument specific detail and work in astronomical units, for example, ‘wavelength range’ and not grism or filter name. Data providers are then advised to systematically collect metadata (‘data about data’) about the curation process, assign unique identifiers, describe the general content (e.g., physical coverage) of a collection, and provide interface and capability parameters of public services. Finally, the VO will work at its best with high-level (‘science-ready’) data, so that the VO user is spared as much as possible any complex and time consuming data reduction. Data centres should then make an effort to provide such data.

Padovani, Paolo

2007-08-01

 
 
 
 
61

Performance Evaluation for VoIP on Campus  

Directory of Open Access Journals (Sweden)

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

Rendy Munadi

2013-09-01

62

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

International Nuclear Information System (INIS)

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

63

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: Spanish Abstract in spanish La biomasa y productividad de una comunidad de pastos marinos es útil para determinar el estado ecológico de la costa. Se comparó la biomasa foliar y la densidad de vainas en praderas de Thalassia testudinum Banks & Sol. ex K. D. Koenig, en dos ambientes de la costa del Caribe mexicano (N= 6 cuadran [...] tes/sitio) en Noviembre de 1998. Los valores de vainas y biomasa foliar fueron más bajos en la pradera asociada al manglar, que en la pradera establecida en una laguna arrecifal. Esto probablemente se deba a que las hojas del manglar tuvieron porcentaje más alto de epífitas. Por otro lado, T. testudinum tuvo mayor biomasa que Syringodium filiforme Kütz en la laguna arrecifal. Abstract in english The biomass and productivity of a seagrass community are useful for determining the ecological status of the coast. Leaf biomass and shoot density in beds of Thalassia testudinum Banks & Sol. ex K. D. Koenig, were compared for two environments in the Mexican Caribbean coast (N= 6 quadrants/site) in [...] November 1998. Shoot and leaf biomass values were lower in the mangrove-associated meadow than in the reef lagoon meadow. This could be related to the higher percentage of epiphytes on mangrove leaves. In addition, T. testudinum had more biomass than Syringodium filiforme Kütz in the reef lagoon.

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

2000-06-01

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

Science.gov (United States)

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

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

2014-06-01

65

Nanostructured WO3 /BiVO4 photoanodes for efficient photoelectrochemical water splitting.  

Science.gov (United States)

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

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

2014-09-24

66

Drowning in Data : VO to the rescue  

CERN Document Server

Astronomical datasets are growing in size and diversity, posing severe technical problems. At the same time scientific goals increasingly require the analysis of very large amounts of data, and data from multiple archives. The Virtual Observatory (VO) initiative aims to make multiwavelength science and large database science as seamless as possible. It can be seen as the latest stage of a long term trend towards standardisation and collectivisation in astronomy. Within this inevitable trend, we can avoid the high energy style of building large fixed hierarchical teams, and keep the individualist style of astronomical research, if the VO is used to build a facility class data infrastructure. I describe how the VO works and how it may change in the Web 2.0 era.

Lawrence, A

2009-01-01

67

Ca3(VO4)2-LaVO4 cation conductors  

International Nuclear Information System (INIS)

Electric conductivity, ionic numbers of transfer, phase transitions of vanadates Ca3-xLa2x/3(VO4)2, where 0 ? x ? 1 were studied experimentally. It was ascertained that the compounds are solid electrolytes in terms of calcium ions. At low temperatures the value of calcium conductivity is the maximum one in the vanadates Ca2La2/2(VO4)2 featuring palmierite structure, at high temperatures - in ?'-Ca3(VO4)2 vanadate with a whitlockite-like structure. Mechanisms of calcium ion transfer are discussed

68

COMPUTER SIMULATION IN THE ELECTRONICS EDUCATION FOCUSED TO INCREASE THE SPECIAL HIGH SCHOOL STUDENTS MOTIVATION II. / Po?íta?ové modelovanie vo výu?be elektroniky zamerané na zvýšenie motivácie žiakov SOŠ II  

Directory of Open Access Journals (Sweden)

Full Text Available The authors interpret the particular results of their research in this contribution. It is focused to the impact of computer model on education. Anticipated result is the higher efficiency of special education here. This aim is achieved by application of motivation relations in coherence with exploitation easy reached free software. At the same time here is the latest technology, based on the computer design of circuits, applied here.Tento príspevok je pokra?ovaním prvej ?asti, ktorá bola zameraná na zvýšenie motivácie prostredníctvom bezplatne získate?ného softvéruzo siete internet. Obsahom druhej ?asti príspevku je súbor ukážok jednosmernej, striedavej a transiert analýzy elektronických obvodov.

ArpᚠJúlius

2008-02-01

69

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

Science.gov (United States)

VO2 max is the maximum amount of oxygen a person can consume and the value does not change despite an increase in workload. There is lack of data evaluating the impact of factors, which could affect VO2 max measurement, particularly in Indian population. The objectives of the present study were (i) to estimate VO2 max in a young healthy Indian population and to compare it with available prediction equations for Indian population (ii) to correlate time to achieve VO2 max with the relative VO2 max (iii) to assess the factors affecting the time to achieve VO2 max measurement (body composition and physical activity level). Twenty healthy adult males (18-30 years) underwent detailed anthropometry, physical activity level and modified Bruce protocol for VO2 max assessment. Breath by breath VO2, VCO2, oxygen saturation, heart rate, blood pressure were measured continuously and following exercise protocol. There was an internal validity between the estimated VO2 max and the maximum heart rate (MHR) (r = 0.51, P < 0.05). Respiratory rate and tidal volume significantly correlated with VO2 max P < 0.01). Linear regression analysis indicated physical activity level (PAL) was a strong predictor of time to reach VO2 max. Out of the 3 prediction equations computed to estimate VO2 max, 2 equations significantly overestimated VO2 max. In Conclusion, physical activity level emerged to be a strong predictor of time to VO2 max. Time to achieve VO2 max is an important factor to be considered when determining VO2 max. There was an overestimation in the VO2 max values derived from predicted equations. PMID:24617157

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

2013-01-01

70

Enhanced luminescence by charge compensation in red-emitting Eu3+-activated Ca3Sr3(VO4)4  

International Nuclear Information System (INIS)

The effects of charge compensation on the luminescence behavior of a red-emitting phosphor, Ca3Sr3(VO4)4:Eu3+, were investigated. It has been observed that charge compensated by monovalent ions, especially Na+, shows greatly enhanced red emission under ultraviolet excitation. It is found that Na2CO3 addition acts as a fluxing agent and plays a role in charge compensation, which clearly improves the emission intensity of Eu3+-activated Ca3Sr3(VO4)4. Enhanced emission intensity of the corresponding charge compensated phosphors under ultraviolet radiation may find application in the production of red phosphors for white light-emitting diodes.

71

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Garci?a Morales, Jose? Luis; Romero, L. I.; Sales, D.

2008-01-01

72

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 co...

Eric Wong-González; Patricia Esquivel-Rodríguez; Wendy Zumbado-Rivera

2006-01-01

73

From hollow olive-shaped BiVO4 to n-p core-shell BiVO4@Bi2O3 microspheres: controlled synthesis and enhanced visible-light-responsive photocatalytic properties.  

Science.gov (United States)

In this study, hollow olive-shaped BiVO(4) and n-p core-shell BiVO(4)@Bi(2)O(3) microspheres were synthesized by a novel sodium bis(2-ethylhexyl)sulfosuccinate (AOT)-assisted mixed solvothermal route and a thermal solution of NaOH etching process under hydrothermal conditions for the first time, respectively. The as-obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, Brunauer-Emmett-Teller surface area, and UV-vis diffuse-reflectance spectroscopy in detail. The influence of AOT and solvent ratios on the final products was studied. On the basis of SEM observations and XRD analyses of the samples synthesized at different reaction stages, the formation mechanism of hollow olive-shaped BiVO(4) microspheres was proposed. The photocatalytic activities of hollow olive-shaped BiVO(4) and core-shell BiVO(4)@Bi(2)O(3) microspheres were evaluated on the degradation of rhodamine B under visible-light irradiation (? > 400 nm). The results indicated that core-shell BiVO(4)@Bi(2)O(3) exhibited much higher photocatalytic activities than pure olive-shaped BiVO(4). The mechanism of enhanced photocatalytic activity of core-shell BiVO(4)@Bi(2)O(3) microspheres was discussed on the basis of the calculated energy band positions as well. The present study provides a new strategy to enhancing the photocatalytic activity of visible-light-responsive Bi-based photocatalysts by p-n heterojunction. PMID:21171642

Guan, Mei-Li; Ma, De-Kun; Hu, Sheng-Wei; Chen, Yan-Jun; Huang, Shao-Ming

2011-02-01

74

Asignación de biomasa y rendimiento de girasol con relación al nitrógeno y densidad de población  

Directory of Open Access Journals (Sweden)

Full Text Available Se realizó un estudio con girasol (Helianthus annuus L., bajo condiciones de temporal, en Montecillo, México, para determinar el efecto de la aplicación de 0 y 100 kg de N ha-1 y 57 000 (80*25 cm y 114 000 (40*25 cm plantas ha-1 sobre la producción de biomasa, su distribución en la planta, el rendimiento y sus componentes. El N y 100 kg ha-1 de P2O5 se aplicaron a todo el experimento al momento de la siembra. El diseño experimental fue en bloques completos al azar con arreglo en parcelas divididas y cuatro repeticiones. El N y el aumento en densidad de población no afectaron la distribución (% de materia seca en los órganos de la planta. Por otra parte, la acumulación de materia seca (g m-2 en cada estructura de la planta se incrementó al aplicar N y con el uso de poblaciones altas. Esto condujo a una mayor producción de biomasa, rendimiento y un número más alto de semillas m-2 (NSMC. El NSMC fue el componente de mayor correlación con el rendimiento. El peso de 100 semillas (P100S no registró cambios significativos por efecto de los tratamientos. Además, al combinar el N con densidad alta, se logró una mayor producción de biomasa y rendimiento.

Ricardo Vega Mu\\u00F1oz

2001-01-01

75

Biomasa e índices fisiológicos en chile morrón cultivado en altas densidades  

Directory of Open Access Journals (Sweden)

Full Text Available Se estudió la acumulación y distribución de biomasa y su relación con algunos indicadores de eficiencia fisiológica en chile morrón (Capsicum annum L. cv. ?Ariane?, cultivado en invernadero e hidroponía en distintas condiciones de manejo. Se manejaron tres densidades de población: 8 y 14 plantas/m2 despuntadas por encima de la tercera y cuarta bifurcación respectivamente (D8 y D14, y un testigo a 3.3 plantas/m2 sin despunte. Se hicieron cuatro muestreos: en transplante, amarre del primer fruto (40 días después del transplante [ddt], crecimiento de los primeros frutos (70 ddt, y al final de la cosecha (158 ddt. La tasa de fotosíntesis se midió en hojas bien iluminadas con un analizador de gases al infrarrojo, en cuatro ocasiones (a los 40, 54, 68 y 82 ddt. Después de los 40 ddt, el testigo acumuló más biomasa por planta que las otras densidades de población, debido a su mayor área foliar. Sin embargo, por tener mayor densidad, D8 y D14 produjeron mayores índices de área foliar, lo que se correlacionó directamente con mayores cantidades de biomasa y rendimiento de frutos/m2. La tasa de fotosíntesis se incrementó durante el crecimiento de los primeros frutos en alrededor de 65 % (de 12 a 20 µmol CO2 m-2 s-1.

Nicacio Cruz-Huerta

2005-01-01

76

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

Directory of Open Access Journals (Sweden)

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.

Floriberto Solis-Mendoza

2012-01-01

77

Using VoIP to compete.  

Science.gov (United States)

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

Werbach, Kevin

2005-09-01

78

Middleware for Data Visualization in VO-enabled Data Archives  

Science.gov (United States)

We present middleware for visualization and exploration of complex datasets in a VO framework, that performs interaction between data archives and existing VO client applications using PLASTIC. It comprises: (1) PLASTIC-enabled Java control applet, integrated into archive web-pages and interacting with VO applications; (2) cross-browser compatible JavaScript part managing PLASTIC-aware VO Clients (launch, data manipulation) by means of Java LiveConnect. This (or similar) solution is an essential for the new generation VO-enabled data archives providing access to complex observational and theoretical datasets (3D-spectroscopy, N-body simulations, etc.) through web-interface. Thanks to PLASTIC capabilities it is possible to start all necessary client software with a single-click in the archive query result page in a web-browser. This simplifies the scientific usage of the VO resources and makes it easy even for users with no experience in the VO technologies.

Zolotukhin, I.; Chilingarian, I.

2008-08-01

79

Middleware for Data Visualization in VO-enabled Data Archives  

CERN Document Server

We present a middleware for visualization and exploration of complex datasets in a VO framework, that performs interaction between data archives and existing VO client applications using PLASTIC. It comprises: (1) PLASTIC-enabled Java control applet, integrated into archive web-pages and interacting with VO applications; (2) cross-browser compatible JavaScript part managing PLASTIC-aware VO Clients (launch, data manipulation) by means of Java LiveConnect. This (or similar) solution is an essential for the new generation VO-enabled data archives providing access to complex observational and theoretical datasets (3D-spectroscopy, N-body simulations, etc.) through web-interface. Thanks to PLASTIC capabilities it is possible to start all necessary client software with a single-click in the archive query result page in a web-browser. This simplifies the scientific usage of the VO resources and makes it easy even for users with no experience in the VO technologies.

Zolotukhin, Ivan

2007-01-01

80

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

Scientific Electronic Library Online (English)

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

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

2012-12-01

 
 
 
 
81

Modular VO oriented Java EE service deployer  

Science.gov (United States)

The International Virtual Observatory Alliance (IVOA) has produced many standards and recommendations whose aim is to generate an architecture that starts from astrophysical resources, in a general sense, and ends up in deployed consumable services (that are themselves astrophysical resources). Focusing on the Data Access Layer (DAL) system architecture, that these standards define, in the last years a web based application has been developed and maintained at INAF-OATs IA2 (Italian National institute for Astrophysics - Astronomical Observatory of Trieste, Italian center of Astronomical Archives) to try to deploy and manage multiple VO (Virtual Observatory) services in a uniform way: VO-Dance. However a set of criticalities have arisen since when the VO-Dance idea has been produced, plus some major changes underwent and are undergoing at the IVOA DAL layer (and related standards): this urged IA2 to identify a new solution for its own service layer. Keeping on the basic ideas from VO-Dance (simple service configuration, service instantiation at call time and modularity) while switching to different software technologies (e.g. dismissing Java Reflection in favour of Enterprise Java Bean, EJB, based solution), the new solution has been sketched out and tested for feasibility. Here we present the results originating from this test study. The main constraints for this new project come from various fields. A better homogenized solution rising from IVOA DAL standards: for example the new DALI (Data Access Layer Interface) specification that acts as a common interface system for previous and oncoming access protocols. The need for a modular system where each component is based upon a single VO specification allowing services to rely on common capabilities instead of homogenizing them inside service components directly. The search for a scalable system that takes advantage from distributed systems. The constraints find answer in the adopted solutions hereafter sketched. The development of the new system using Java Enterprise technologies can better benefit from existing libraries to build up the single tokens implementing the IVOA standards. Each component can be built from single standards and each deployed service (i.e. service components instantiations) can consume the other components' exposed methods and services without the need of homogenizing them in dedicated libraries. Scalability can be achieved in an easier way by deploying components or sets of services on a distributed environment and using JNDI (Java Naming and Directory Interface) and RMI (Remote Method Invocation) technologies. Single service configuration will not be significantly different from the VO-Dance solution given that Java class instantiation that benefited from Java Reflection will only be moved to Java EJB pooling (and not, e.g. embedded in bundles for subsequent deployment).

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

2014-07-01

82

Reduced monoclinic BiVO? for improved photoelectrochemical oxidation of water under visible light.  

Science.gov (United States)

A monoclinic BiVO4 film was grown on a transparent conducting substrate for photoelectrochemical oxidation of water. A photocurrent up to 2.3 mA cm(-2) under visible light (? > 420 nm) was achieved after treating the sample simply by electrochemical reduction followed by NaBH4. The high photocurrent is believed to be due to the improved carrier separation and transportation as a result of increased donor density. PMID:24718651

Qin, Dong-Dong; Wang, Ting; Song, Yu-Min; Tao, Chun-Lan

2014-06-01

83

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

Directory of Open Access Journals (Sweden)

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

Marcos David Silva-Cavalcante

2013-01-01

84

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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

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

85

Steganography of VoIP streams  

CERN Document Server

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.

Mazurczyk, Wojciech

2008-01-01

86

VOSA: A VO Spectral Energy Distribution Analyzer  

Science.gov (United States)

VOSA (VO Sed Analyzer)1 is a public web-tool developed by the Spanish Virtual Observatory2, and designed to help astronomers to build and analyze Spectral Energy Distributions (SEDs) for many objects at the same time (tested for ˜2000 objects), combining user inputs with Virtual Observatory data. VOSA offers different workflows for stars (and brown dwarfs) and galaxies given that the physics involved is different in many aspects and, thus, the relevant VO , theoretical models, etc are also different. VOSA is in operation since 2008 (Bayo et al. 2008) although several important improvements have been done since then and will be done in the future (mostly taking into account user requests). It has proved to be a useful tool with more than 200 users analyzing more than 165.000 objects (only last year) and around 35 published papers making use of VOSA.

Rodrigo, C.; Bayo, A.; Solano, E.; Barrado y Navascués, D.

2014-05-01

87

Drowning in Data : VO to the rescue  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Astronomical datasets are growing in size and diversity, posing severe technical problems. At the same time scientific goals increasingly require the analysis of very large amounts of data, and data from multiple archives. The Virtual Observatory (VO) initiative aims to make multiwavelength science and large database science as seamless as possible. It can be seen as the latest stage of a long term trend towards standardisation and collectivisation in astronomy. Within this ...

Lawrence, A.

2009-01-01

88

What are suspicious VoIP delays?  

CERN Document Server

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

Mazurczyk, Wojciech; Szczypiorski, Krzysztof

2010-01-01

89

Status of VO-Theory Standards and Implementations at VO-Paris Data Centre  

Science.gov (United States)

Along with the new generation of instruments in astronomy, initiatives in the VO community have been focusing more and more on theoretical standards. Indeed, a scientific return of large observational facilities will only be possible if the community has access to state of the art simulation codes and simulation results. As a first step, the VO-Theory Interest Group at IVOA has developed a data model (SimDM) that can describe any kind of simulations for diffusion in a VO context. Current developments aim at extending the Theory architecture adding a semantic layer to enhance SimDM as well as a simulation data access layer to easily and universally access theoretical data. All is designed with interoperability in mind.

Languignon, D.; Petit, F. L.; Moreau, N.; Ooghe, B.; Zwölf, C. M.; Alimi, J.; Meliani, Z.; Hennebelle, P.; Rasera, Y.; Roy, F.

2012-09-01

90

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

Directory of Open Access Journals (Sweden)

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

V. Mart\\u00EDnez

2005-01-01

91

Efecto de la aplicación de hojarasca de mucuna sobre densidad y biomasa de lombrices de tierra  

Directory of Open Access Journals (Sweden)

como ingenieros del ecosistema han mostrado ser una herramienta viable. La Mucuna pruriens var. Utilis (mucuna, leguminosa utilizada en los campos agrícolas tropicales, se usó en este experimento, en dos cantidades, 1.5 y 4.5 kg m-2, en forma de hojarasca, como fuente de materia orgánica fresca, con el fin de incrementar la abundancia de las lombrices de tierra in situ durante un año. Esta hojarasca se aplicó de tres formas: en la superficie, en el interior, y en la superficie y en el interior en un campo de maíz de 30 x 37 m, generando tres tratamientos con 1.5 kg m-2, tres tratamientos con 4.5 kg m-2 y dos testigos: parcelas sin mucuna, un testigo con laboreo y otro testigo sin laboreo; se constituyeron los ocho tratamientos evaluados, mismos que contaron con tres repeticiones, distribuyéndose en bloques al azar en el área experimental. Después de un año de experimentación, en las parcelas donde se adicionó la mucuna se registró la mayor densidad (99.2 ± 44.6 individuos m-2 y biomasas (10.6 ± 5.6 g m-2 de lombrices en cuadrantes donde la Mucuna se aplicó en la superficie, en cantidad de 4.5 kg m-2. Se obtuvo también la mayor producción de maíz (70.3 ± 22.6 g individuos m-2, P < 0.05. El efecto de esta leguminosa no se apreció sobre la especie cosmopolita endogea Polypheretima elongata, la cual presentó su mayor biomasa en los cuadrantes sin mucura (16.8 ± 10.2 g m-2, P < 0.05. Se observó el efecto del laboreo sobre esta lombriz, registrándose la menor biomasa en los cuadrantes sin mucuna y con laboreo (3 ± 0.4 g m-2.

Esperanza Huerta

2005-01-01

92

Asignación de biomasa y rendimiento de girasol con relación al nitrógeno y densidad de población  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se realizó un estudio con girasol (Helianthus annuus L.), bajo condiciones de temporal, en Montecillo, México, para determinar el efecto de la aplicación de 0 y 100 kg de N ha-1 y 57 000 (80*25 cm) y 114 000 (40*25 cm) plantas ha-1 sobre la producción de biomasa, su distribución en la planta, el rendimiento y sus componentes. El N y 100 kg ha-1 de P2O5 se aplicaron a todo el experimento al momento de la siembra. El diseño experimental fue en ...

Oz, Ricardo Vega Muu F.; Alberto Escalante Estrada, J.; Nchez Garcu Eda, Prometeo Su E.; Carlos Ramu00EDrez Ayala; Ernesto Cuenca Adame

2001-01-01

93

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

Scientific Electronic Library Online (English)

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

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

1337-13-01

94

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

Scientific Electronic Library Online (English)

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

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

95

RESERVAS DE BIOMASA DE ÁRBOLES DISPERSOS EN POTREROS Y MITIGACIÓN AL CAMBIO CLIMÁTICO  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ubicadas 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 val...

Mario Chacu00F3n-Leu00F3n; Celia Alice Harvey

2013-01-01

96

Magnetoelastic effects in rare-earth vanadates YbVO4 and HoVO4  

Science.gov (United States)

Magnetoelastic anomalies in the thermal expansion and Young modulus, as well as the ? E-effect in rare-earth vanadates RVO4 ( R = Ho, Yb), are investigated experimentally and theoretically. A considerable softening of the Young modulus is observed for HoVO4 and YbVO4 at T Young modulus of an isotropic polycrystal from various elastic modes have been averaged. For the Yb vanadate, considerable magnetoelastic anomalies in the thermal expansion along the tetragonal a and c axes have been discovered. The magnetoelastic contributions are used for determining completely symmetric magnetoelastic coefficients; the role of the completely symmetric quadrupole constant for magnetoelastic effects is analyzed.

Kazei, Z. A.; Chanieva, R. I.

2006-02-01

97

Deployment of VoIP Technology: QoS Concerns  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Lazzez, Amor; Slimani, Thabet

2013-01-01

98

The Na2O-CaO-V2O5 system with 0-50 mol. % V2O5  

International Nuclear Information System (INIS)

The data on binary and ternary oxide compounds related to the Na2O-CaO-V2O5 system in the area of Na2O-NaV3-Ca(VO3)2-CaO are studied. Formation of sodium vanadates NaVO3, Na5V3O10, Na3VO4 and calcium vanadates Ca(VO3)2, Ca2V2O7, Ca3(VO4)2, Ca7V4O17, binary vanadates Na2Ca(VO3)4, Na3Ca2V3O11, NaCaVO4, NaCa4(VO4)2 and solid solution on the ?-Ca3(VO4)2 basis is confirmed. Formation of Ca4V2O9, Ca5V2O10, Na2CaV2O7 and Na4C12(V2O7)7 is not confirmed. Formation of the binary pyrovanadate of the Na2Ca-(V2O7)4 composition is established. The IR-spectra are studied for five vanadates. Elementary three-component systems in the area under consideration are identified and the phase diagram for subsolidus temperatures is plotted

99

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se determinó la bioadsorción de Cadmio (II) en solución por la biomasa celular de quince hongos, por el método colorimétrico de la ditizona. La biomasa de Mucor rouxii IM-80 fue más eficiente en la remoción de Cadmio (II) en solución (8.2 mg/g) seguida de M. rouxii mutante (7.1 mg/g), A. flavus I (5.9 mg/g) y Helminthosporium sp (5.4 mg/g). Para la biomasa de M. rouxii-IM-80, la mayor bioadsorción fue a pH= 5.0-6.0, a 28ºC durante 40 horas con 1.0 mg/200 mL de concentración inicial...

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

2007-01-01

100

PyVO: Python access to the Virtual Observatory  

Science.gov (United States)

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

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

2014-02-01

 
 
 
 
101

Direct synthesis of thermochromic VO2 through hydrothermal reaction  

Science.gov (United States)

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

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

2014-04-01

102

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

103

Biomasa aérea, cantidad y calidad de semilla de Melinis repens (Willd. Zizka, en Aguascalientes, México  

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manualmente forraje y semilla. Se determinó la producción de forraje, producción de espiguillas y número de semillas por metro cuadrado. Se valoró la viabilidad, germinación y latencia de la semilla a diferentes tiempos después de la cosecha. La producción de biomasa aérea difirió (P<0.05 con promedios de 2913 a 1736 kg MS ha-1 en 2008 y de 1488 a 707 kg MS ha-1 en 2009 (menos lluvioso, con mayor producción en Calvillo. La producción de semillas varió (P<0.05 de 1,239 a 2,401 semillas m2 en 2008 y de 1,452 a 3,906 semillas m2 en 2009. La viabilidad en la semilla fue de 32 a 54 %, sin diferencias significativas. Calvillo presentó mayor germinación (25 %, la cual fue aumentando y a los 18 meses casi toda la semilla viable germinó (43 %. En El Llano la germinación fue menor (2 % debido a la latencia, con poco aumento aún después de 24 meses, llegando a 15 %. Este pasto presentó niveles altos de producción de biomasa aérea y semilla, lo que puede favorecer su capacidad invasora, aunque también puede ser una ventaja para la conservación de suelos. La semilla presentó mayor producción y latencia en condiciones de escasez de agua.

Abraham D\\u00EDaz Romo

2012-01-01

104

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

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

J. Gardu\\u00F1o-Gonz\\u00E1lez

2009-01-01

105

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

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

Jorge M Mendoza

2012-01-01

106

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

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Full Text Available Los sistemas de gasificación de Biomasa son una alternativa para emplear residuos agroindustriales y generar un combustible ga- seoso; 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, por 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 descenden- te 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.

Carlos A. Forero N\\u00FA\\u00F1ez

2013-01-01

107

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish 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

Magaly, Ruiz; Jorge, Paolini.

2004-04-01

108

CONCENTRACIÓN DE CARBONO EN LA BIOMASA AÉREA DEL MATORRAL ESPINOSO TAMAULIPECO  

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

Jos\\u00E9 I. Yerena-Yamallel

2011-01-01

109

Electronic structure of the band-filling-controlled CaVO3 and LaVO3 compounds  

International Nuclear Information System (INIS)

We studied the electronic structure of the band-filling CaVO3 and LaVO3 compounds. The experimental techniques were photoemission (PES) and x-ray absorption (XAS) spectroscopy. The experimental results were analyzed using an extended cluster model. The ground states of CaVO3 and LaVO3 are highly covalent and contain a considerable 3dn+1L contribution. The CaVO3 compound is in the charge transfer regime (? 3 material is in the intermediate regime (? ? U). The spectral weight distributions reveal that CaVO3 is a coherent metal and that LaVO3 is a p-d insulator. The photoemission of CaVO3 shows the coherent peak (3d1C) and the incoherent feature (3d1L). The spectrum of insulating LaVO3 presents only the incoherent structure (3d2L), whereas the coherent peak is replaced by the Mott-Hubbard screening (3d2D). This transfer of spectral weight is responsible for the opening of the experimental bandgap. The incoherent feature contains a considerable O 2p character and cannot be attributed to the lower Hubbard band. Further, the relative V 3d-O 2p cross section helps to explain the photon energy dependence of the PES spectra. The addition spectra of both CaVO3 and LaVO3 are dominated by the 3dn+1 final state configuration. The distribution of spectral weightn. The distribution of spectral weight is mainly dictated by intra-atomic exchange and crystal field splittings. The coherent contribution is less important than in photoemission, and is greatly diminished in the O 1s x-ray absorption spectra.

110

The Effect of Habitual Smoking on VO2max  

Science.gov (United States)

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 (psmokers.

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

2008-01-01

111

Photoemission study of TiO2/VO2 interfaces  

CERN Document Server

We have measured photoemission spectra of two kinds of TiO$_2$-capped VO$_2$ thin films, namely, that with rutile-type TiO$_2$ (r-TiO$_2$/VO$_2$) and that with amorphous TiO$_2$ (a-TiO$_2$/VO$_2$) capping layers. Below the Metal-insulator transition temperature of the VO$_2$ thin films, $\\sim 300$ K, metallic states were not observed for the interfaces with TiO$_2$, in contrast with the interfaces between the band insulator SrTiO$_3$ and the Mott insulator LaTiO$_3$ in spite of the fact that both TiO$_2$ and SrTiO$_3$ are band insulators with $d^0$ electronic configurations and both VO$_2$ and LaTiO$_3$ are Mott insulators with $d^1$ electronic configurations. We discuss possible origins of this difference and suggest the importance of the polarity discontinuity of the interfaces. Stronger incoherent part was observed in r-TiO$_2$/VO$_2$ than in a-TiO$_2$/VO$_2$, suggesting Ti-V atomic diffusion due to the higher deposition temperature for r-TiO$_2$/VO$_2$.

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

2006-01-01

112

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  

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Full Text Available O propósito deste estudo foi verificar, em futebolistas profissionais, o impacto de sete intervalos de tempo sobre a variável fisiológica consumo máximo de oxigênio (VO2 máx. Dezoito jogadores de futebol com média de idade de 24 ± 4 anos (18-31, peso de 72,5 ± 5,9kg (62-83 e estatura de 176,5 ± 7,0cm (164-188 foram submetidos a teste ergométrico máximo em esteira rolante, utilizando-se protocolo escalonado contínuo. A resposta de freqüência cardíaca (FC foi registrada por meio de um eletrocardiógrafo computadorizado de 12 derivações simultâneas. A ventilação pulmonar (V E, o consumo de oxigênio (VO2, a produção de dióxido de carbono (VCO2 e a razão de troca respiratória (RER foram calculadas a partir de valores medidos por um sistema espirométrico computadorizado. Os resultados deste estudo demonstraram que houve variabilidade significante do VO2 máx (p The purpose of this investigation was to verify the impact of seven ventilatory time intervals on the maximum oxygen uptake (VO2 max in professional soccer players. Eighteen male soccer players aged 24.4 ± 4 (18-31, weight 72.5 ± 5.9 kg (62-83 and height 176.5 ± 7 cm (164-188 were submitted to a maximum exercise test on treadmill, using the continuous protocol. The heart rate response was recorded by means of computerized ECG with 12 leads, simultaneously. The respiratory exchange ratio, carbon dioxide production, oxygen uptake and pulmonary ventilation were calculated by means of the spirometric computerized system. The results of this study demonstrated that there was significant variability (p < 0.05 in VO2 max only when it was compared instantaneously and by breath-by-breath response, in relation to other intervals analyzed (10, 20, 30, 40, 50 and 60 seconds, respectively. In conclusion, the authors observed that VO2 max increases were proportional to those found in the ventilatory sample intervals during the progressive intensity exercise. However, the higher time interval underestimated its increase. Thus, the authors suggest that the investigator should utilize mean intervals in a range between 10 and 60 seconds, since no significant statistic difference was verified among these intervals.

Paulo Roberto Santos Silva

1999-04-01

113

Revisión sobre la corrosión de tubos sobrecalentadores en plantas de biomasa  

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

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

Berlanga-Labari, C.

2006-08-01

114

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

Scientific Electronic Library Online (English)

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

María del Rosario, Iglesias; Alicia Haydée, Barchuk.

2010-04-01

115

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)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish 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.

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

116

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)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish 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.

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

2010-03-01

117

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

Scientific Electronic Library Online (English)

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

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

118

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Se determinó la bioadsorción de Cadmio (II) en solución por la biomasa celular de quince hongos, por el método colorimétrico de la ditizona. La biomasa de Mucor rouxii IM-80 fue más eficiente en la remoción de Cadmio (II) en solución (8.2 mg/g) seguida de M. rouxii mutante (7.1 mg/g), A. flavus I (5 [...] .9 mg/g) y Helminthosporium sp (5.4 mg/g). Para la biomasa de M. rouxii-IM-80, la mayor bioadsorción fue a pH= 5.0-6.0, a 28ºC durante 40 horas con 1.0 mg/200 mL de concentración inicial de Cadmio (II) y 80 mg/200 mL de biomasa celular. Se concluye que algunas biomasas fúngicas remueven eficientemente Cadmio (II) en solución y pueden utilizarse para descontaminar nichos acuáticos contaminados con este metal Abstract in english The biosorption of dissolved Cadmium (II) using cellular biomass of 15 fungi, using a dithizone colorimetric method, was determined. The Mucor rouxii IM-80 biomass was more efficient in removing Cadmium (II) from solution (8.2 mg/g), followed by the M. rouxii mutant (7.1 mg/g), Aspergillus flavus I [...] (5.9 mg/g) and Helminthosporium sp (5.4 mg/g) biomasses. The highest biosorption for M. rouxii IM-80 was at pH 5.0-6.0, at 28ºC for 40 h employing 1.0 mg/200mL of Cadmium (II) as initial concentration, and 80 mg/200 mL of fungal biomass. It was concluded that some fungal biomass efficiently removed Cadmium (II) from solution and could be used for decontamination of aquatic habitats polluted with this metal

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

119

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

Directory of Open Access Journals (Sweden)

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.

TATIANA RODRIGUEZ CHAPARRO

2010-01-01

120

The Effect of Habitual Smoking on VO2max  

Science.gov (United States)

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.

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

2008-01-01

 
 
 
 
121

The Effect of Habitual Smoking on VO2max  

Science.gov (United States)

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

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

2008-01-01

122

Nanoscale Thermal Mapping of VO2  

Science.gov (United States)

We present a method for nanoscale thermal imaging of insulating thin films. We image the local temperature of the metal-insulator transition in a VO2 film, and investigate the role of Joule heating in two-terminal geometry. By sweeping the voltage applied to a conducting atomic force microscope tip in contact mode, we locally trigger and detect the transition to the metallic phase. By fitting the Poole-Frenkel conduction regime immediately preceding the transition, we extract the local temperature. Finally, we find grains displaying two electronic transitions, consistent with a locally stable intermediate insulating phase.[4pt] We acknowledge financial support from Harvard's Nanoscale Science and Engineering Center, funded by NSF grant PHY 01-17795 and the Sloan Fellowship. Adam Pivonka acknowledges the support of the New York Community Trust--George Merck Fund. Magdalena Huefner acknowledges the support of the Deutsche Forschungsgemeinschaft (HU 1960/11).

Pivonka, Adam; Huefner, Magdalena; Ko, Changhyun; Frenzel, Alex; O'Connor, Kevin; Ramanathan, Shriram; Hudson, Eric; Hoffman, Jennifer

2013-03-01

123

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

Directory of Open Access Journals (Sweden)

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

Ignacio Winfield

2007-03-01

124

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

Scientific Electronic Library Online (English)

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

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

125

Origins of superior symmetrical doping ability of monoclinic BiVO4  

Science.gov (United States)

Application of semiconductors for functional devices depends critically on their dopability. However, there are strong doping bottlenecks for wide-band-gap semiconductors -- symmetrical doping is usually difficult, which severely restrict their potential applications. Here, we report superior symmetrical doping properties, i.e., n-type and p-type, of monoclinic BiVO4 by first-principles density-functional theory calculation. Our results reveal that without external doping, BiVO4 with moderate n-type and p-type conductivities can be obtained. However, doping of Sr, Ca, Na, and K atoms under oxygen-rich growth conditions can lead to outstanding p-type conductivity, whereas doping of Mo and W under oxygen-poor growth conditions can result in excellent n-type conductivity. We find that Bi 6s state is responsible for the good p-type doping and the presence of V 3d state is responsible for the good n-type doping. Furthermore, the Bi 6s and V 3d states are also responsible for producing very dispersive valence and conduction band edges, leading to small electron and hole effective masses. The superior symmetrical doping properties and high carrier mobility make BiVO4 a promising candidate for electronic and optoelectronic device applications.

Yan, Yanfa; Yin, Wan-Jian; Wei, Su-Huai; Al-Jassim, Mowafak; Turner, John

2011-03-01

126

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

CERN Document Server

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

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

2011-01-01

127

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).

128

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)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese 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

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

129

Gipsy 3D: Analysis, Visualization and Vo-Tools  

CERN Document Server

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

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

2009-01-01

130

The VO-Neural project: recent developments and some applications  

CERN Document Server

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.

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

2008-01-01

131

The Effect of Habitual Smoking on VO2max  

Science.gov (United States)

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 (psignificant (R2 change = 0.7%, p<0.01). Post hoc analysis showed that compared to Never Smoked, the effects on VO2max from Light and Regular smoking habits were -0.83 and -0.85 ml.kg- 1.min-1 respectively (p<0.05). The effect of Heavy smoking on VO2max was -2.56 ml.kg- 1.min-1 (p<0.001). The CE s of each smoking 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.

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

2008-01-01

132

Thermochromic VO2 nanorods and other vanadium oxides nanostructures  

International Nuclear Information System (INIS)

Thermochromic VO2 nanorods were prepared via thermal conversion of the metastable VO2-B phase synthesized by hydrothermal methods. We observe an increased thermochromic transition temperature to ?75-80 deg. C by variable-temperature infrared spectroscopy. Nano- and sub-micron structures of other vanadium oxides (V3O7 (NH4)0.5V2O5, and V2O5) were obtained simply by varying the starting materials in the hydrothermal synthesis. We also obtained nanostructures of the high temperature tetragonal rutile phase of VO2 by thermolysis of single-source vanadium (IV) precursors

133

Controlled synthesis of VO2(R), VO2(B), and V2O3 vanadium-oxide nanowires  

International Nuclear Information System (INIS)

Vanadium-oxide nanowires (NWs) V2O5, VO2(R), VO2(B), and V2O3 are deposited on a substrate to study their field-emission properties. V2O5 NWs are prepared by thermal evaporation via vapor transport of a vanadium-oxide complex under mild conditions. Films of VO2 and V2O3 wires are subsequently prepared by reducing V2O5 one-dimensional nanocrystals at 450 °C with hydrogen gas. The composition of the flowing H2/Ar mixture and the duration of reduction are utilized to control the formation of VO2(R) or VO2(B) NWs. The crystallinity and morphology of products as prepared are characterized using several techniques, including powder X-ray diffraction, a scanning electron microscope, and a transmission electron microscope. The field-emission properties of the vanadium-oxide NWs as prepared exhibit a turn-on field of 4.56–7.65 V/?m and an emission current density up to 3.68–8.36 mA/cm2. These features indicate that vanadium-oxide NWs have potential FE emitter applications.Graphical AbstractV2O5, VO2(R), VO2(B), and V2O3 NWs were synthesized via thermal evaporation and controlled reduction process. Field-emission properties of these NWs exhibited turn-on fields of 4–8 V/?m, an emission cu

134

Depressed phase transition in solution-grown VO2 nanostructures.  

Science.gov (United States)

The first-order metal-insulator phase transition in VO(2) is characterized by an ultrafast several-orders-of-magnitude change in electrical conductivity and optical transmittance, which makes this material an attractive candidate for the fabrication of optical limiting elements, thermochromic coatings, and Mott field-effect transistors. Here, we demonstrate that the phase-transition temperature and hysteresis can be tuned by scaling VO(2) to nanoscale dimensions. A simple hydrothermal protocol yields anisotropic free-standing single-crystalline VO(2) nanostructures with a phase-transition temperature depressed to as low as 32 degrees C from 67 degrees C in the bulk. The observations here point to the importance of carefully controlling the stoichiometry and dimensions of VO(2) nanostructures to tune the phase transition in this system. PMID:19505072

Whittaker, Luisa; Jaye, Cherno; Fu, Zugen; Fischer, Daniel A; Banerjee, Sarbajit

2009-07-01

135

Density functional theory study of rutile VO2 surfaces  

CERN Document Server

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

Mellan, Thomas A

2012-01-01

136

Monitoring Architecture for Lawful Interception in VoIP Networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lawful Interception is one of the main provisions needed for the security agencies to monitor a suspect or deal with criminal activities. The implementation of this was easy in the traditional telephone networks, because of its centralized administration. However this has become a tedious job with the emergence of VoIP technologies where voice traffic is carried over IP. In this paper, we discuss the challenges and propose a monitoring architecture for Lawful Interception on VoIP networks bas...

Karpagavinayagam, Balamurugan; State, Radu; Festor, Olivier

2007-01-01

137

Enhanced optical response of hybridized VO2/graphene films  

Science.gov (United States)

Application of graphene as transparent electrodes is an active research area due to its excellent electrical and optical properties. Vanadium dioxide (VO2) is an attractive material since it is a thermochromic material that undergoes a structural phase transition when heat is applied. The phase transition results in the change of electrical and optical characteristics. We report optical characteristics of hybrid materials of graphene and VO2. We observed a 12% improvement in infrared transmittance with VO2 films deposited on graphene sapphire substrates compared to that of bare sapphire substrates. We also found that the phase transition temperature decreases as the number of graphene layers on the substrates increases. In the case of VO2 films on the substrate that was coated with four layers of graphene, the mean phase transition temperature was lowered to ~56 °C.Application of graphene as transparent electrodes is an active research area due to its excellent electrical and optical properties. Vanadium dioxide (VO2) is an attractive material since it is a thermochromic material that undergoes a structural phase transition when heat is applied. The phase transition results in the change of electrical and optical characteristics. We report optical characteristics of hybrid materials of graphene and VO2. We observed a 12% improvement in infrared transmittance with VO2 films deposited on graphene sapphire substrates compared to that of bare sapphire substrates. We also found that the phase transition temperature decreases as the number of graphene layers on the substrates increases. In the case of VO2 films on the substrate that was coated with four layers of graphene, the mean phase transition temperature was lowered to ~56 °C. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34054f

Kim, Hyeongkeun; Kim, Yena; Kim, Taeyoung; Jang, A.-Rang; Jeong, Hu Young; Han, Seung Ho; Yoon, Dae Ho; Shin, Hyeon Suk; Bae, Dong Jae; Kim, Keun Soo; Yang, Woo Seok

2013-03-01

138

Producción de biomasa y utilización de Leucaena leucocephala fertilizada y pastoreada por ovinos  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Un experimento de campo fue realizado en la sección de ovinos de la Facultad de Agronomía de la Universidad Central de Venezuela, ubicado en Maracay, estado Aragua para evaluar el efecto de la fertilización con S, Cu y Zn sobre la producción de biomasa Leucaena leucocephala y su utilización por ovin [...] os a pastoreo. Se utilizó una asociación de la leguminosa sembrada en hileras sencillas de 1 x 4 m, en un potrero de Cynodon plectostachyous. Se usó un diseño de bloques al azar con tres repeticiones, utilizando ocho tratamientos que incluyeron un testigo negativo (sin fertilización), un testigo positivo (S, Cu y Zn) y los seis restantes con un elemento faltante. Se hicieron cuatro muestreos destructivos y no destructivos; los primeros se realizaron sobre 10 plantas, evaluando altura promedio, número de ramas, longitud de tallos con Ø 6 mm, número de hojas, longitud de hojas, materia seca de hojas (MSH), materia seca de tallos con Ø 6 mm (MST>) para generar ecuaciones de regresión y estimar la producción de biomasa. Para los muestreos no destructivos, se evaluaron las mismas variables mencionadas anteriormente con excepción de las de materia seca. Hubo diferencias (P y la participación de la MST0,05). La utilización de L. leucocephala no fue afectada (P>0,05) por los tratamientos. Los resultados indican que bajo estas condiciones, la aplicación de S de L. leucocephala aumenta la producción de biomasa, pero no afecta su utilización por ovinos a pastoreo. Abstract in english A field experiment was carried out in the Sheep Section of the Faculty of Agronomy of the Central University of Venezuela, located in Maracay, Aragua state to evaluate the effect of the fertilization of Leucaena leucocephala on the biomass production and its utilization for grazing sheep. An associa [...] tion of the legume already sown in single rows of 1x4 m, on a pasture of Cynodon plectostachyous, was used. An aleatory block design was used with three repetitions, including a negative control (without fertilization) and a positive control (S, Cu, and Zn) and the six remaining treatments with a missing element. Four destructive and non destructive samplings were made; the first was made on 10 plants, evaluating height, number of branches, length of branches Ø 6 mm, number of leaves, length of leaves, dry matter of leaves, dry matter of branches Ø 6 mm. For the non destructive samplings, except for dry matter, the same variables were evaluated. There were differences (P and the % of participation of the MST 0.05). The utilization of the L. leucocephala was not affected (P>0.05) by the treatments. The results indicated that under these conditions, the fertilization of L. leucocephala increased the biomass production, but it did not affect its utilization by grazing sheep.

Selina, Camacaro; Wilfre, Machado.

139

Audio Codecs in VoIPv6: A Performance Analysis  

Directory of Open Access Journals (Sweden)

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

Monjur Ahmed

2014-04-01

140

The preparation of a plasmonically resonant VO2 thermochromic pigment  

International Nuclear Information System (INIS)

Vanadium dioxide (VO2) undergoes a reversible metal-insulator transition, normally at ?68 0C. While the properties of continuous semi-transparent coatings of VO2 are well known, there is far less information available concerning the potential use of discrete VO2 nanoparticles as a thermochromic pigment in opaque coatings. Individual VO2 nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO2 nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO2 powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties.

 
 
 
 
141

The preparation of a plasmonically resonant VO2 thermochromic pigment.  

Science.gov (United States)

Vanadium dioxide (VO(2)) undergoes a reversible metal-insulator transition, normally at approximately 68 degrees C. While the properties of continuous semi-transparent coatings of VO(2) are well known, there is far less information available concerning the potential use of discrete VO(2) nanoparticles as a thermochromic pigment in opaque coatings. Individual VO(2) nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO(2) nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO(2) powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties. PMID:19417455

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

2009-02-25

142

Sustitución de una caldera de gasóleo por una caldera de biomasa en el hogar de la tercera edad de Villamuriel de Cerrato  

Digital Repository Infrastructure Vision for European Research (DRIVER)

El presente proyecto tiene por objetivo la sustitución de la actual caldera de gasóleo por una nueva caldera de biomasa en el “Hogar de la Tercera Edad” de la localidad de Villamuriel de Cerrato (Palencia). Con ello se pretende, tanto modernizar la actual sala de calderas adaptándola al uso de biomasa y renovando los equipos obsoletos, como adaptar el edificio a la normativa vigente, cumpliendo con las exigencias establecidas por el nuevo Código Técnico de la Edificaci...

Franco Valderra?bano, Elena; Fuente Paz, Rube?n

2013-01-01

143

Conversión hidrotérmica suscritica de residuos orgánicos y biomasa. Mecanismos de reacción Subcritical hydrothermal conversion of organic wastes and biomass. Reaction pathways  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

144

Variables de influencia en la productividad de biomasa de matorral en la mancomunidad de El Alto Jarama-Atazar  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La situación energética actual, caracterizada por la búsqueda de nuevas fuentes de energía, sustitutivas de los combustibles fósiles tradicionales y menos agresivas con el medio ambiente, ha hecho necesaria la puesta en marcha de políticas y acuerdos a nivel mundial, que buscan reducir la contaminación y fomentar las energías renovables. La biomasa, recurso renovable perteneciente a cada país y con un poder calorífico suficientemente alto como para emplearse energéticamente, surge ...

Sa?nchez France?s, R.; Ordax Castro, C.; Quijano Pedrosa, A.

2008-01-01

145

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Alfonso Solar, David

2013-01-01

146

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Gallego Cipre?s, Oscar

2013-01-01

147

Carbono en biomasa microbiana y carbono soluble como indicadores de calidad de Vertisoles cultivados con caña azucarera  

Digital Repository Infrastructure Vision for European Research (DRIVER)

El objetivo del presente estudio fue identificar propiedades biológicas, químicas y físicas del suelo, como el carbono de la biomasa microbiana (Cbio), el carbono orgánico soluble (COS), el pH, la materia orgánica (MO), la capacidad de intercambio catiónico (CIC) y la densidad parente (Dap), como indicadores de calidad del cambio de uso del suelo de selva a cultivo de caña de azúcar en la Chontalpa, Tabasco. Se muestreó un Vertisol de selva y cuatro Vertisoles cultivados con caña de...

Liliana Armida-Alcudia; David Espinosa-Victoria; Pez, David J. Palma-lu F.; Arturo Galvis-Spinola; Sergio Salgado-Garcu00EDa

2005-01-01

148

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Yusleidis Cisnero Reyna; Pez, Bienvenido Sarru Eda Lu F.; Lez, Luis Zamora Gonzu E.

2005-01-01

149

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

Science.gov (United States)

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

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

2014-01-01

150

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

Directory of Open Access Journals (Sweden)

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

Rosa de Lourdes Romo Campos

2009-01-01

151

Neutron diffraction study of YVO3, NdVO3, and TbVO3  

CERN Document Server

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

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

2006-01-01

152

THE E-LEARNIG MODUL OF HEALTH EDUCATION / E-learningový modul vzdelávania vo výchove k zdraviu  

Directory of Open Access Journals (Sweden)

Full Text Available The Learning Management System Moodle is favorite learning environment in the high schools and universities. This is our contribution to new learning technologies in nursing education. We used e-learning portal Constantine the Philosopher University in Nitra and made e-learning course health education. This course we made in the project E-learnig Modul of Health Education with subsidy The Cultural and Educational Grant Agency at the Ministry of Education, Slovak Republic. The E-learning Modul of Health Education contain these courses: Health education - M. Líšková, Education in the nursing work-1. Nádaská, Nursing in community health care - M. Boledovi?ová, Oncological education - Z. Schmidtové, Surgical nursing - J. Mesárošová, Psychiatrical nursing -D. Zrubcová, Neurological nursing - A. Solgajová.Learning Management System Moodle je výu?bové prostredie, ktoré má najmä na vysokých školách výraznú ob?ubu a dáva predpoklady na jeho použitie vo vzdelávaní sestier. V projekte E-learningový modul vzdelávania vo výchove k zdraviu pre bakalárske štúdium ošetrovate?stva, ktorý bol podporený Kultúrnou a eduka?nou grantovou agentúrou Ministerstva školstva SR (KEGA, sme využili e-learningový vzdelávací portál Univerzity Konštantína Filozofa v Nitre. E-learningový modul vzdelávania vo výchove k zdraviu obsahuje nasledovné kurzy: Výchova k zdraviu - M. Líšková, Eduka?ná ?innos? sestry -1. Nádaská, Ošetrovate?stvo v komunite a primárnej zdravotnej starostlivosti - M. Boledovi?ová, Ošetrovate?stvo vo vybraných odboroch so zameraním na onkologickú výchovu - Z. Schmidtové, Ošetrovate?stvo - M. Líšková, Chirurgické ošetrovate?stvo - J. Mesárošová, Psychiatrické ošetrovate?stvo - D. Trubcové, Neurologické ošetrovate?stvo - A. Solgajová.

Líšková Miroslava

2008-10-01

153

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

Directory of Open Access Journals (Sweden)

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

Jos\\u00E9 C. Villar

2008-01-01

154

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

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

Carlos Francisco Gonz\\u00E1lez Hern\\u00E1ndez

2014-01-01

155

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

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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.

Jorge Ignacio del Valle

2011-09-01

156

Spectroscopic Analysis in the Virtual Observatory Environment with SPLAT-VO  

CERN Document Server

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...

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

2014-01-01

157

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

CERN Document Server

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

Shen, Charles

2008-01-01

158

The Effect of Habitual Smoking on VO2max  

Science.gov (United States)

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 (p<0.01) as the level of smoking exposure increased. GLM #1 showed that age, gender, PASS and BMI were independently related with VO2max (R2 = 0.642, SEE = 4.90, p<0.001). The added pack.y variables in GLM #2 were statistically significant (R2 change = 0.7%, p<0.01). Post hoc analysis showed that compared to Never Smoked, the effects on VO2max from Light and Regular smoking habits were -0.83 and -0.85 ml.kg- 1.min-1 respectively (p<0.05). The effect of Heavy smoking on VO2max was -2.56 ml.kg- 1.min-1 (p<0.001). The CE s of each smoking 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.

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

2008-01-01

159

Structural characterization of PrVO3 epitaxial thin films  

CERN Document Server

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...

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

160

One-step hydrothermal conversion of VO2(B) into W-doped VO2(M) and its phase transition and optical switching properties  

Science.gov (United States)

W-doped monoclinic vanadium dioxide VO2(M) nanobelts have been transformed from VO2(B) nanobelts in the presence of tungstic acid by a facile one-step hydrothermal route for the first time. The as-prepared samples were characterized by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and variable-temperature infrared spectroscopy (IR). The results show that W atoms are doped into the crystal lattice of VO2(M) matrix, and the morphology and size of the as-obtained VO2(M) nanobelts are dependent on that of the precursor VO2(B). The phase transition temperature (Tc) of W-doped VO2(M) can be tuned by W doping. The variable-temperature IR reveals that the as-synthesized W-doped VO2(M) nanobelts have outstanding thermochromic characters and optical switching properties.

Zhang, Yifu; Zhang, Xiongzhi; Huang, Yu; Huang, Chi; Niu, Fei; Meng, Changgong; Tan, Xiaoyu

2014-02-01

 
 
 
 
161

POSSIBILITIES AND NECESSITIES OF INNOVATION IN TEACHING / Možnosti a potreby inovácií vo vyu?ovaní  

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Full Text Available Author deals with actual questions of teaching process and didactics. He indicates the possibilities and the need of changes in the educational process. These changes relate to contentual, but also processual aspects of educational process dominated by innovative educational methods and approaches. This report presents a complex view of innovation in education.Príspevok sa zaoberá aktuálnymi otázkami vyu?ovacieho procesu a didaktiky a nazna?uje možnosti a potreby zmien vo výchovno-vzdelávacom procese. Zmeny sa týkajú nielen obsahových, ale aj procesuálnych stránok vyu?ovacieho procesu, v ktorom musia prevláda? inovatívne vyu?ovacie metódy a prístupy. Príspevok podáva komplexnejší poh?ad na inovácie vo vyu?ovaní.

Petlák Erich

2008-11-01

162

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

Scientific Electronic Library Online (English)

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

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

1257-12-01

163

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

Directory of Open Access Journals (Sweden)

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

Maria Isabel Criales-Hernández

2006-12-01

164

Phase relation of system LiVO3-NiO and some properties of LiNiVO4  

International Nuclear Information System (INIS)

The phase equilibrium relationship of the system LiVO3-NiO in the three component system Li2O-NiO-V2O5 was investigated by means of high and normal temperature X-ray diffraction techniques, thermogravimetric analysis, and differential thermal analysis. The phase diagram of the system LiVO3-NiO was constructed in the temperature range between 5000 and 15500C. The successive processes in air from a mixture of Li2CO3, NiO, and V2O5 to a spinel type compound LiNiVO4 proceeded through the formation of both LiNi(VO3)3 and LiVO3. The lattice constant of LiNiVO4 at 10000C worked out at 8.220 +- 0.001 A, whereas it was 8.217 A at 7000C. About the change in the lattice constant it appeared that the cation arrangement in LiNiVO4 is (Ni sub(x)V sub(1-x))sup( i v)(LiNi sub(1-x)V sub(x))sup( v i)O4 (1>x>0.15), so that the change may be caused by an increase in the concentration of Ni2+ ion in the tetrahedral sites. However, local occupancy of Li+ in the four coordination positions and oxygen deficiency at high temperature are also possible, so that these may leave problems to be solved in future. For LiNiVO4 the electric conductivities over the temperature range from 2500 to 10500C and the thermoelectromotive forces at about 9000C were measured. Activation energies 1.48 eV above 8100C and 0.557 eV below 8100C came out from the electric conductivity measurements. Oxygen partial pressure dependence of the electric conductivity of LiNiVO4 was examined over the range 6 x 10-5 to 1 atm of P sub(O2). No correlation was gained in the P sub(O2) ranges 6 x 10-5 to 4 x 10-3 and 1 x 10-1 to 1 atm, but the electric conductivity was in proportion to P sub(O2)sup(-0.23) over P sub(O2) 4 x 10-3 to 1 x 10-1 atm. (author)

165

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

Scientific Electronic Library Online (English)

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

Rafael, Tizol Correa.

166

Intestinal absorption and secretion of radioactive vanadium (48VO-3) in rats and effect of Al(OH)3  

International Nuclear Information System (INIS)

Sprague-Dawley rats (180-300 g) were fasted overnight and gavaged with 5 ?mol Na3VO4 in 1.0 ml 0.9% NaCl containing 1 ?Ci 48V. Control animals (n = 12) simultaneously received 1.0 ml diluent and experimental animals (n = 12) received 1 ml Al(OH)3. Diluent and Al(OH)3 were then given daily for 4 d. Urine and feces were collected separately each day. In control animals total 48V recovery (stool and urine) over 4 d was 86.6 +/- 2.4% of the administered dose. Although Al(OH)3 insignificantly increased total 48V recovery (93.6 +/- 3.2%), it markedly increased excretion of 48V in the stool as compared to the urine (control:stool, 69.1 +/- 1.8%; urine, 12.5 +/- 1.3%; Al(OH)3:stool, 85.7 +/- 1.5%; urine, 7.9 +/- 1.8%). Animals were then sacrificed and tissue uptake of tracer measured. The pattern of unexcreted 48V in tissues of both groups was kidney > bone > liver > intestine > muscle, but the tissue levels were uniformly higher in controls than in Al(OH)3-treated animals. The ability of Al(OH)3 to remove endogenous VO-3 was also examined. 48V was injected ip (n = 20). Half of the animals received diluent and half received 1.0 ml Al(OH)3 by gavage daily for 4 d. There were no differences in the pattern of 48V tissue distribution and excretion. It is concluded that Al(OH)3 may prevent tissue accumulation of VO-3 from dietary sources by reducing intestinal VO-3 absorption

167

Spectroscopic characteristics of GdVO4: Dy3+ crystal  

Science.gov (United States)

Room temperature optical absorption, emission spectrum of GdVO4: Dy3+ crystal grown by Czochralski (CZ) method were measured and analyzed. Spectral parameters were calculated in the framework of the Judd-Ofelt theory. The GdVO4: Dy3+ crystal showed two intense and relatively broad absorption bands in UV wavelength range centered at 390 and 453 nm and two prominent emission peaks located at blue 485 and yellow 575 nm. The corresponding absorption and emission cross sections were estimated and the luminescence decay curve was analyzed. Optical spectroscopy investigations indicate that GdVO4: Dy3+ crystal would be a promising blue and yellow solid state laser material.

Ning, Kaijie; He, Xiaoming; Zhang, Lianhan; Liu, Youchen; Yin, Jigang; Zhang, Peixing; Chen, Guangzhu; Wang, Xiangyong; Chen, Zhe; Shi, Chunjun; Hong, Jiaqi; Hang, Yin

2014-11-01

168

A VO-driven Astronomical Data Grid in China  

CERN Document Server

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

Cui, Chenzhou; Yang, Yang; Zhao, Yongheng

2010-01-01

169

Thermochromic VO2 on Zinnwaldite Mica by pulsed laser deposition  

Science.gov (United States)

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

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

2014-09-01

170

Optical response of multilayer thermochromic VO2-based structures  

Science.gov (United States)

We considered the emissivity properties of VO2 thin films as a function of temperature through several simulations, considering different substrates and multilayer structures. Formulating the concept of emissivity tunability is introduced and we found that a large difference in emissivity, below and above the transition temperature, can be obtained which may be used for the design of medium-wave infrared (3 to 5 ?m) filters. Specifically, we optimized a multilayer structure, to function as a low-emissivity filter, at high temperature for the reduction of infrared signature. The values of emissivity changes, found for a VO2/metal multilayer, are larger than the value of a single layer of VO2.

Li Voti, Roberto; Larciprete, Maria Cristina; Leahu, Grigore; Sibilia, Concita; Bertolotti, Mario

2012-01-01

171

Solution-processed phase-change VO(2) metamaterials from colloidal vanadium oxide (VO(x)) nanocrystals.  

Science.gov (United States)

We demonstrate thermally switchable VO2 metamaterials fabricated using solution-processable colloidal nanocrystals (NCs). Vanadium oxide (VOx) NCs are synthesized through a nonhydrolytic reaction and deposited from stable colloidal dispersions to form NC thin films. Rapid thermal annealing transforms the VOx NC thin films into monoclinic, nanocrystalline VO2 thin films that show a sharp, reversible metal-insulator phase transition. Introduction of precise concentrations of tungsten dopings into the colloidal VOx NCs enables the still sharp phase transition of the VO2 thin films to be tuned to lower temperatures as the doping level increases. We fabricate "smart", differentially doped, multilayered VO2 films to program the phase and therefore the metal-insulator behavior of constituent vertically structured layers with temperature. With increasing temperature, we tailored the optical response of multilayered films in the near-IR and IR regions from that of a strong light absorber, in a metal-insulator structure, to that of a Drude-like reflector, characteristic of a pure metallic structure. We demonstrate that nanocrystal-based nanoimprinting can be employed to pattern multilayered subwavelength nanostructures, such as three-dimensional VO2 nanopillar arrays, that exhibit plasmonic dipolar responses tunable with a temperature change. PMID:24377298

Paik, Taejong; Hong, Sung-Hoon; Gaulding, E Ashley; Caglayan, Humeyra; Gordon, Thomas R; Engheta, Nader; Kagan, Cherie R; Murray, Christopher B

2014-01-28

172

Providing VoD Streaming Using P2P Networks  

Science.gov (United States)

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

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

173

Infrared-sensitive electrochromic device based on VO2  

Science.gov (United States)

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

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

2013-10-01

174

Phase transformation of VO2 nanoparticles assisted by microwave heating.  

Science.gov (United States)

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

Phoempoon, Phatcharee; Sikong, Lek

2014-01-01

175

Metodología de diseño e implementación de soluciones voIP  

Directory of Open Access Journals (Sweden)

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

Wilson A. Bulla B.

2012-12-01

176

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: Spanish Abstract in spanish En este artículo se discute la relación existente entre la enfermedad pulmonar obstructiva crónica (EPOC) y el humo de biomasa. Más de la mitad de la población utiliza biomasa como combustible principal, sobre todo en áreas rurales y en países en vías de desarrollo donde su uso llega hasta el 80%. L [...] a inhalación del humo de biomasa crea un estado inflamatorio crónico, que se acompaña de una activación de metaloproteinasas y una reducción de la movilidad mucociliar. Esto podría explicar la gran asociación existente entre la exposición a biomasa y EPOC, revelada por estudios observacionales y epidemiológicos provenientes de países en vías de desarrollo y de países desarrollados. En esta revisión exploramos también las diferencias entre la EPOC causada por tabaco y por biomasa, y encontramos que, a pesar de las diferencias fisiopatológicas, la mayoría de las características clínicas, calidad de vida y mortalidad fueron parecidas. En los últimos diez años se han realizado intervenciones para disminuir la exposición a biomasa mediante el uso de cocinas mejoradas y combustibles limpios, sin embargo, estas estrategias todavía no han sido exitosas debido a su incapacidad para reducir los niveles de contaminación a niveles recomendados por la Organización Mundial de la Salud, y por su falta de uso. Por lo tanto, hay una necesidad urgente de ensayos de campo aleatorios, cuidadosamente realizados, para determinar la verdadera gama de reducciones de contaminación potencialmente alcanzables, la probabilidad de su uso y los beneficios a largo plazo en la reducción de la gran carga mundial de EPOC Abstract in english In this article, the relationship between chronic obstructive pulmonary disease (COPD) and biomass smoke will be discussed. More than half of the world population uses biomass for fuel, especially in rural areas and in developing countries where usage reaches 80%. Biomass smoke inhalation creates an [...] inflammatory chronic state, which is accompanied by metalloproteinases activation and mucociliary mobility reduction. This could explain the existing association between biomass exposure and COPD, revealed by observational and epidemiological studies from developing and developed countries. In this review, the differences between COPD caused by tobacco and biomass were explored. It was found that despite the pathophysiological differences, most of the clinical characteristics, quality of life and mortality were similar. In the last ten years there have been interventions to reduce the biomass smoke exposure by using improved stoves and cleaner fuels. However, these strategies have not yet been successful due to inability to reduce contamination levels to those recommended by the World Health Organization as well as due to the lack of use. Therefore, there is an urgent need for carefully conducted, randomized field trials to determine the actual range of potentially reachable contamination reductions, the probability of use and the long term benefits of reducing the global burden of COPD

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

2014-03-01

177

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

Scientific Electronic Library Online (English)

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

Magalis, Zabala; Yrma, Gómez.

2010-09-01

178

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish En este artículo se discute la relación existente entre la enfermedad pulmonar obstructiva crónica (EPOC) y el humo de biomasa. Más de la mitad de la población utiliza biomasa como combustible principal, sobre todo en áreas rurales y en países en vías de desarrollo donde su uso llega hasta el 80%. L [...] a inhalación del humo de biomasa crea un estado inflamatorio crónico, que se acompaña de una activación de metaloproteinasas y una reducción de la movilidad mucociliar. Esto podría explicar la gran asociación existente entre la exposición a biomasa y EPOC, revelada por estudios observacionales y epidemiológicos provenientes de países en vías de desarrollo y de países desarrollados. En esta revisión exploramos también las diferencias entre la EPOC causada por tabaco y por biomasa, y encontramos que, a pesar de las diferencias fisiopatológicas, la mayoría de las características clínicas, calidad de vida y mortalidad fueron parecidas. En los últimos diez años se han realizado intervenciones para disminuir la exposición a biomasa mediante el uso de cocinas mejoradas y combustibles limpios, sin embargo, estas estrategias todavía no han sido exitosas debido a su incapacidad para reducir los niveles de contaminación a niveles recomendados por la Organización Mundial de la Salud, y por su falta de uso. Por lo tanto, hay una necesidad urgente de ensayos de campo aleatorios, cuidadosamente realizados, para determinar la verdadera gama de reducciones de contaminación potencialmente alcanzables, la probabilidad de su uso y los beneficios a largo plazo en la reducción de la gran carga mundial de EPOC Abstract in english In this article, the relationship between chronic obstructive pulmonary disease (COPD) and biomass smoke will be discussed. More than half of the world population uses biomass for fuel, especially in rural areas and in developing countries where usage reaches 80%. Biomass smoke inhalation creates an [...] inflammatory chronic state, which is accompanied by metalloproteinases activation and mucociliary mobility reduction. This could explain the existing association between biomass exposure and COPD, revealed by observational and epidemiological studies from developing and developed countries. In this review, the differences between COPD caused by tobacco and biomass were explored. It was found that despite the pathophysiological differences, most of the clinical characteristics, quality of life and mortality were similar. In the last ten years there have been interventions to reduce the biomass smoke exposure by using improved stoves and cleaner fuels. However, these strategies have not yet been successful due to inability to reduce contamination levels to those recommended by the World Health Organization as well as due to the lack of use. Therefore, there is an urgent need for carefully conducted, randomized field trials to determine the actual range of potentially reachable contamination reductions, the probability of use and the long term benefits of reducing the global burden of COPD

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

2014-01-01

179

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

Directory of Open Access Journals (Sweden)

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

Marisol GALLEGOS-GARC\\u00CDA

2010-01-01

180

New refinement of the room-temperature structure of LiCuVO sub 4  

Energy Technology Data Exchange (ETDEWEB)

Lithium copper(II) vanadate, M{sub r}=207.43, orthorhombic, Imma, a=5.662(1), b=5.809(1), c=8.758(2) A, V=288.0(2) A{sup 3}, Z=4, D{sub x}=4.78 Mg m{sup -3}, Mo K{alpha}, {lambda}=0.71069 A, {mu}=10.4 mm{sup -1}, F(000)=348, R=0.040 for 461 unique reflections. The sample was prepared by hydrothermal growth (T=919 K, P=190 MPa, 48 h) of 1.5 g of a powder of LiCuVO{sub 4} in 1.65 cm{sup 3} of 0.1 M NaF aqueous solution. LiCuVO{sub 4} is an orthorhombic distortion of the cubic spinel structure, with V{sup 5+} on tetrahedral sites and Li{sup +} and Cu{sup 2+} distributed in an ordered way on the octahedral sites. This leads to edge-sharing chains of Li{sup +} and Cu{sup 2+} octahedra running along (100) and (010), respectively. (orig.).

Lafontaine, M.A.; Leblanc, M.; Ferey, G. (Le Mans Univ., 72 (France). Lab. de Fluorures)

1989-08-15

 
 
 
 
181

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

Directory of Open Access Journals (Sweden)

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

LILIAN M. MEDEROS CUERVO

1995-12-01

182

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Ru00E9gulo Jimu00E9nez Guillu00E9n; Raymundo Quero Carrillo, Adriu E. N.; Rez, Jorge Pu E. Rez Pu E.; Ndez, Pedro Arturo Martu Ednez Hernu E.; Ndez Garay, Alfonso Hernu E.; Jorge Leonardo Tovar Salinas; Claudia Isabel Hidalgo Moreno; Ndez, Sau Fal Rojas Hernu E.

2013-01-01

183

Bu? zmenou, ktorú chceš vo svete vidie?  

Directory of Open Access Journals (Sweden)

Full Text Available „Reklama primäla týchto ?udí nahá?a? sa za autami a šatami, ktoré nepotrebujú. Generácie pracujú v zamestnaniach, ktoré neznášajú, len aby si mohli kúpi? to, ?o v skuto?nosti nepotrebujú. A tak sme sa ocitli v situácii, ke? nevlastníme veci, ale veci vlastnia nás“,  (Klub bitkárov, 1999.Od úsvitu ?udstva je každá spolo?nos? charakteristická aplikovaním jedine?nej stratégie prežitia vzh?adom na okolité prostredie a okolité spolo?nosti. Tieto stratégie sa líšia predovšetkým svojím dosahom na životné prostredie a na ?udí, ktorí v ?om žijú. Hlavne za obdobie posledných 10 000 rokov, teda približne od dôb prvej domestikácie rastlín a zvierat, sa ve?a stratégií uberalo nie ve?mi priaznivým smerom, ?o dokazujú nelichotivé štatistiky ?udských obetí a vy?erpaných ekosystémov. Žia?, tento trend sa neustále stup?uje a jeho najvä?ším vyvrcholením je práve sú?asnos?. Ak sa bavíme o nejakom civiliza?nom pokroku a neustálom rozvoji, toto je potom jeho temná stránka, ktorá je ale ?asto ignorovaná a prehliadaná. ?o teda urobi? pre to, aby bol vývoj udržate?ný?

Peter Ma?o

2011-12-01

184

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

Science.gov (United States)

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…

Zwiren, Linda D.; And Others

1991-01-01

185

Fabrication and Electrical Properties of Pure VO2 Phase Films  

CERN Document Server

We have grown VO2 thin films by laser ablation for electronic device applications. In obtaining the thin films of the pure VO2 phase, oxygen partial pressure is a critical parameter because vanadium oxides have several phases with the oxygen concentration. It is found that the pure VO2 films are grown on Al2O3 substrate in the narrow ranges of 55-60 mTorr in an Ar+10% O2 ambient, and that the mixed phase films are synthesized when the deposition pressure slightly deviates from the optimum pressure. The (100) oriented VO2 films undergo an abrupt metal-insulator transition (MIT) with resistance change of an order of 104 at 338K. In the films of mixed phases, the small change of the resistance is observed at the same temperature. The polycrystalline films are grown on SiO2/Si substrate, and undergo a broaden MIT of the resistance. This may be attributed to mixed phases generated in the films because of a coarse interface states. Furthermore, the abrupt MIT and collective current motion appearing in metal are obs...

Chae, B G; Kim, H T; Maeng, S Y; Kang, K Y

2003-01-01

186

Optical diffraction in ordered VO2 nanoparticle arrays  

Science.gov (United States)

The potential of oxide electronic materials as multifunctional building blocks is one of the driving concepts of the field. In this presentation, we show how nanostructured particle arrays with long-range order can be used to modulate an optical response through exploiting the metal-insulator transition of vanadium dioxide. Arrays of VO2 nanoparticles with long-range order were fabricated by pulsed laser deposition in an arbitrary pattern defined by focused ion-beam lithography. The interaction of light with the nanoparticles is controlled by the nanoparticle size, spacing and geometrical arrangement and by switching between the metallic and semiconducting phases of VO2. In addition to the near-infrared surface plasmon response observed in previous VO2 studies, the VO2 nanoparticle arrays exhibit size-dependent optical resonances in the visible region that likewise show an enhanced optical contrast between the semiconducting and metallic phases. The collective optical response as a function of temperature gives rise to an enhanced scattering state during the evolving phase transition, while the incoherent coupling between the nanoparticles produces an order-disorder-order transition.

Lopez, Rene; Feldman, Leonard; Haglund, Richard

2006-03-01

187

Resonantly pumped room temperature Ho:LuVO4 laser.  

Science.gov (United States)

Spectroscopic characterization of a Ho:LuVO4 crystal grown by the Czochralski method has been performed, including the absorption and emission spectra. We demonstrate a 2 ?m room temperature Ho:LuVO4 laser, resonantly pumped by a 1.94 ?m Tm:YAP laser. By use of an output coupler with T=10% transmission, the Ho:LuVO4 laser generated continuous-wave output power of 2.5 W at 2074.18 nm, with a beam quality factor of Mx2=My2=1.3, for a total incident pump power of 19.4 W. The slope efficiency with respect to the pump power was 17.6%, and the optical-to-optical efficiency was 12.9%. Moreover, we obtained a Ho:LuVO4 laser that operated at 2073.77 and 2055.27 nm, by using different output couplers with transmissions of T=15 and 30%. PMID:25361346

Yao, B Q; Cui, Z; Duan, X M; Du, Y Q; Han, L; Shen, Y J

2014-11-01

188

Improving Quality of VoIP over WiMAX  

Directory of Open Access Journals (Sweden)

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

M.A. Mohamed

2012-05-01

189

Synthesis and characterization of FeVO4 nanoparticles  

International Nuclear Information System (INIS)

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

190

Matching of Male and Female Subjects Using VO2 Max.  

Science.gov (United States)

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

Cureton, Kirk J.

1981-01-01

191

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

Index Scriptorium Estoniae

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

Brodneva, Jevgenia

2003-01-01

192

Structure and magnetism of epitaxial PrVO3 films.  

Science.gov (United States)

The interplay between charge, spin, orbital and lattice degrees of freedom in transition metal oxides has motivated extensive research aiming to understand the coupling phenomena in these multifunctional materials. Among them, rare earth vanadates are Mott insulators characterized by spin and orbital orderings strongly influenced by lattice distortions. Using epitaxial strain as a means to tailor the unit cell deformation, we report here on the first thin films of PrVO3 grown on (001)-oriented SrTiO3 substrate by pulsed laser deposition. An extensive structural characterization of the PrVO3 films, combining x-ray diffraction and high-resolution transmission electron microscopy studies, reveals the presence of oriented domains and a unit cell deformation tailored by the growth conditions. We have also investigated the physical properties of the PrVO3 films. We show that, while PrVO3 exhibits an insulating character, magnetic measurements indicate low-temperature hard-ferromagnetic behavior below 80 K. We discuss these properties in view of the thin-film structure. PMID:24214665

Copie, O; Rotella, H; Boullay, P; Morales, M; Pautrat, A; Janolin, P-E; Infante, I C; Pravathana, D; Lüders, U; Prellier, W

2013-12-11

193

Size-dependent optical properties of VO2 nanoparticle arrays  

Science.gov (United States)

Arrays of vanadium oxide nanoparticles with long-range order have been fabricated by pulsed laser deposition in an arbitrary pattern defined by focused ion-beam lithography. Interaction of light with the nanoparticles is controlled by the geometrical arrangement as well as by the differing optical properties displayed by the metallic and semiconducting phases of VO2. Contrary to previous VO2 studies, we observe that the optical contrast between the semiconducting and metallic phases is dramatically enhanced in the visible region, presenting size-dependent optical resonances and size dependent transition temperatures. The collective optical response as a function of temperature presents an enhanced scattering state during the evolving phase transition. The effects appear to arise because of the underlying VO2 mesoscale optical properties, the heterogeneous nucleation behind the phase transition and the incoherent coupling between the nanoparticles undergoing an order-disorder-order transition. Arrays such as this open up new opportunities to study surface plasmon interactions for nanoparticles in close proximity, with the added advantage that the interaction can be switched on by the thermally driven metal-semiconductor phase transition in VO2. This research was supported by the NSF-NIRT program (DMR0210785).

Lopez, Rene

2005-03-01

194

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-06-15

195

Structural aspects of calcium ion transport in Ca3(VO4)2 and Ca3-xNd2x/3(VO4)2 solid solutions  

International Nuclear Information System (INIS)

Experimental data on electric conductivity dependence on temperature in the range of 750-1400 K for Ca3(VO4)2, Ca9Nd(VO4)7 and solid solutions Ca3-xNd2x/3(VO4)2 (0?x?3/7) are presented. It is ascertained that conductivity value in the solid solutions decreases essentially with increase in neodymium concentration. In Ca3(VO4)2 and Ca9Nd(VO4)7 phase transitions at 1383 and 1198 K have been detected. On the basis of the experimental data on conductivity and analysis of polyhedrons of whitlockite-like structure of Ca3(VO4)2 possible ways of calcium cations movement in the structure are discussed and substantiated

196

Thermal and luminescent properties in samples of the Ca3(VO4)2-M3(VO4)2 binary system, where M - Sr, Ba  

International Nuclear Information System (INIS)

A study into the thermal properties of binary systems of Ca3(VO4)2-M3(VO4)2 has shown that the Ca3(VO4)2-Sr3(VO4)2 system is characterized by a peritectic dissociation of the solid solutions at 1480 deg C, whereas that in the Ca3(VO4)2 system occurs at the melting point (1290 deg C). It has been established that activation of the solid solutions through replacement of calcium and strontium or barium orthovanadates by samarium or neodymium permits luminescence yield to be increased 1.1-2.5 times in comparison with Ca3(VO4)2-Sm3+(Nd3+)

197

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

Directory of Open Access Journals (Sweden)

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

Muñoz V. Rosa Elvira

2005-03-01

198

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)

199

The incidence of V?O2 plateau at V?O2max in a cardiac-diseased population.  

Science.gov (United States)

We sought to determine the incidence of V?O(2) plateau at V?O(2)max in a cardiovascular-diseased (CVD) population using 4 different sampling intervals (15-breath moving average, 15?s, 30?s, and 60?s) and 3 different V?O(2) plateau criteria (?50?mL?·?min(-1), ?80?mL?·?min(-1), and ?150?mL?·?min(-1)). A total of 69 people (62 ± 10 yrs.) with recently diagnosed CVD performed a maximal exercise test (10:07 ± 2:24?min) on a treadmill. The test was classified as maximal (n = 57, 2?430 ± 605?mL?·?min(-1)) if self-terminated due to fatigue or classified as symptom-limited (n = 12, 1?683 ± 438?mL?·?min(-1)) if symptoms presented. Chi-square analysis revealed a significant (p statistics: [?50?mL?·?min(-1) (Cramer's V = 0.548, p applied. Based on our findings we recommend a15 breath moving average and V?O(2) plateau criterion of ?50?mL?·?min(-1). PMID:23945973

Nolan, P B; Maddison, R; Dalleck, L

2014-02-01

200

Synthesis, characterisation and catalytic potential of hydrazonato-vanadium(V) model complexes with [VO]3+ and [VO2]+ cores.  

Science.gov (United States)

Reaction between [VO(acac)2] and H2L (H2L are the hydrazones H2sal-nah I or H2sal-fah II; sal = salicylaldehyde, nah = nicotinic acid hydrazide and fah = 2-furoic acid hydrazide) in methanol leads to the formation of oxovanadium(IV) complexes [VOL.H2O](H2L = I: 1, H2L = II: 4). Aerial oxidation of the methanolic solutions of 1 and 4 yields the dinuclear oxo-bridged monooxovanadium(V) complexes [{VOL}2mu-O](H2L = I: 2, H2L = II: 5). These dinuclear complexes slowly convert, in excess methanol, to [VO(OMe)(MeOH)L](H(2)L = I: 9, H(2)L = II: 10), the crystal and molecular structures of which have been determined, confirming the ONO binding mode of the dianionic ligands in their enolate form. Reaction of aqueous K[VO3] with the ligands at pH ca. 7.5 results in the formation of [K(H2O)][VO2L](H2L = I: 3, H2L = II: 6). Treatment of 3 and 6 with H2O2 yields (unstable) oxoperoxovanadium(v) complexes K[VO(O2)L], the formation of which has been monitored spectrophotometrically. Acidification of methanolic solutions of 3 and 6 with HCl affords oxohydroxo complexes, while the neutral complexes [VO2(Hsal-nah)] 7 and [VO2(Hsal-fah)] 8 were isolated on treatment of aqueous solutions of 3 and 6 with HClO4. These complexes slowly transform into 9 and 10 in methanol, as confirmed by 1H, 13C and 51V NMR. The anionic complexes 3 and 6 catalyse the oxidative bromination of salicylaldehyde in water in the presence of H2O2/KBr to 5-bromosalicylaldehyde and 3,5-dibromosalicylaldehyde, a reaction similar to that exhibited by vanadate-dependent haloperoxidases. They are also catalytically active for the oxidation of benzene to phenol and phenol to catechol and p-hydroquinone. PMID:15672198

Maurya, Mannar R; Agarwal, Shalu; Bader, Cerstin; Ebel, Martin; Rehder, Dieter

2005-02-01

 
 
 
 
201

Research on optical property of phase transition PcNi/VO{sub 2} films  

Energy Technology Data Exchange (ETDEWEB)

Highly oriented VO{sub 2} thin films were deposited on sapphire substrate and PcNi thin films were spin coated onto VO{sub 2} thin films. The microstructure of VO{sub 2} thin films were studied with XRD. The phase transition was observed and the change in the optical properties of the PcNi/VO{sub 2} multilayer-films were investigated. It was found that the mid-infrared transmittance of the complex films from 1.5 to 5.5 {mu}m wavelength was raised with PcNi film coating. The thermochromism of PcNi/VO{sub 2} films was not changed compared with VO{sub 2} films and the transition temperature was same to that of VO{sub 2}.

Yuan, H.T. [Department of Physics, Changchun University of Science and Technology, Changchun 130022 (China) and Institute of Physics, Chinese Academy of Science, Beijing 100080 (China)]. E-mail: laogun505@sina.com; Feng, K.C. [Department of Physics, Changchun University of Science and Technology, Changchun 130022 (China); Wang, X.J. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China); He, C.J. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China); Li, D.H. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China); Nie, Y.X. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China); Feng, K.A. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China)

2005-04-30

202

Research on optical property of phase transition PcNi/VO 2 films  

Science.gov (United States)

Highly oriented VO 2 thin films were deposited on sapphire substrate and PcNi thin films were spin coated onto VO 2 thin films. The microstructure of VO 2 thin films were studied with XRD. The phase transition was observed and the change in the optical properties of the PcNi/VO 2 multilayer-films were investigated. It was found that the mid-infrared transmittance of the complex films from 1.5 to 5.5 ?m wavelength was raised with PcNi film coating. The thermochromism of PcNi/VO 2 films was not changed compared with VO 2 films and the transition temperature was same to that of VO 2.

Yuan, H. T.; Feng, K. C.; Wang, X. J.; He, C. J.; Li, D. H.; Nie, Y. X.; Feng, K. A.

2005-04-01

203

Research on optical property of phase transition PcNi/VO2 films  

International Nuclear Information System (INIS)

Highly oriented VO2 thin films were deposited on sapphire substrate and PcNi thin films were spin coated onto VO2 thin films. The microstructure of VO2 thin films were studied with XRD. The phase transition was observed and the change in the optical properties of the PcNi/VO2 multilayer-films were investigated. It was found that the mid-infrared transmittance of the complex films from 1.5 to 5.5 ?m wavelength was raised with PcNi film coating. The thermochromism of PcNi/VO2 films was not changed compared with VO2 films and the transition temperature was same to that of VO2

204

Porous peanut-like Bi2O3-BiVO4 composites with heterojunctions: one-step synthesis and their photocatalytic properties.  

Science.gov (United States)

For the first time, porous peanut-like Bi(2)O(3)-BiVO(4) composites with heterojunctions have been synthesized by a one-step mixed solvothermal method with the assistance of a l-lysine template. A mixture of ethylene glycol (EG) and H(2)O (volume ratio of EG-H(2)O = 3:1) is used as the solvent. Unlike the traditional methods, no concentrated HNO(3) and/or NaOH are involved in diluting Bi and V sources in the adopted approach. The as-synthesized peanut-like samples are rough and porous on the surface and to some extent are interior-hollow. The degradation of methylene blue (MB) is employed to evaluate the photocatalytic activity of the Bi(2)O(3)-BiVO(4) composite. It is observed that the composite performs much better than Bi(2)O(3) and BiVO(4), plausibly due to heterojunctions formed between Bi(2)O(3) and BiVO(4). To investigate the relationship between structure and performance, the as-synthesized samples are characterized by XRD, XPS, SEM, TEM (HRTEM), UV-vis DRS, PL and nitrogen adsorption-desorption methods. Additionally, a possible growth mechanism of this hollow peanut-like structure and the separation process of photogenerated electron-hole pairs on the heterojunctions have been discussed. PMID:22751937

Chen, Lang; Zhang, Qiang; Huang, Rui; Yin, Shuang-Feng; Luo, Sheng-Lian; Au, Chak-Tong

2012-08-21

205

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

Scientific Electronic Library Online (English)

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

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

2010-02-01

206

Gate-tunable gigantic lattice deformation in VO2  

International Nuclear Information System (INIS)

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

207

CAN WE CONFIDENTLY STUDY VO2 KINETICS IN YOUNG PEOPLE?  

Directory of Open Access Journals (Sweden)

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

Samantha G. Fawkner

2007-09-01

208

Structural and physical properties of BiVO3  

International Nuclear Information System (INIS)

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

209

Validity of 3 protocols for verifying VO2 max.  

Science.gov (United States)

The verification bout has emerged as a technique for confirming 'true' VO2 max; however, validity during a single visit is unknown. We evaluated 3 different GXT durations with severe intensity verification bouts. On 3 separate days, in counterbalanced order, 12 recreational-trained men completed short (9±1 min), middle (11±1 min), and long (13±2 min) duration GXTs followed by exhaustive, sine wave verification bouts during the same visit. Intensities for verification were set at speeds equivalent to 2-stages minus end-GXT speed. No differences (pGXT-verification bout testing during a single visit is a valid means of measuring 'true' VO2 max. The 10 min target for GXT duration was the optimum. PMID:21271494

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

2011-04-01

210

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

211

VO2 thermochromic smart window for energy savings and generation  

Science.gov (United States)

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

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

2013-10-01

212

VO2 thermochromic smart window for energy savings and generation  

Science.gov (United States)

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

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

2013-01-01

213

Structural and physical properties of BiVO{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-03-31

214

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

Scientific Electronic Library Online (English)

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

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

2007-06-01

215

Remoción de Cromo (VI) en Solución Acuosa por la Biomasa Celular de Paecilomyces sp. / Removal of Chromium (VI) from Aqueous Solutions by Fungal Biomass of Paecilomyces sp.  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish El objetivo de este trabajo fue determinar la remoción de Cromo (VI) en solución por la biomasa celular del hongo contaminante ambiental Paecilomyces sp. por el método colorimétrico de la difenilcarbazida. La mayor bioadsorción fue a pH= 1.0±0.2, a 50ºC durante 16 horas con 7.2 mg/200 mL de concentr [...] ación inicial de Cromo (VI) y 80 mg/200 mL de biomasa celular. Se concluye que la biomasa fúngica remueve adecuadamente Cromo (VI) en solución y puede utilizarse para descontaminar nichos acuáticos contaminados, ya que 1 g de biomasa fúngica remueve 100 mg/200 mL del metal a las tres horas de incubación. Abstract in english The objective of this work was to determine the removal of Chromium (VI) on the Paecilomyces sp.; fungal biomass, spectrophotometrically using diphenylcarbazide as the complexing agent. The highest adsorption was obtained at pH= 1.0±0.2, at 50ºC after 16 hours of incubation, with 7.2 mg/200 mL of in [...] itial concentration of Chromium (VI) and 80 mg/200 mL of cellular biomass. It was concluded that application of this biomass on the removal of Cr (VI) in aqueous solutions can be used since 1 g of fungal biomass remove 100 mg/200 mL of this metal after three hours of incubation.

Ismael, Acosta; Juan F, Cárdenas; Diana, Alvarado-Hernández; María G, Moctezuma-Zárate.

216

Implementation of Cloud Computing into VoIP  

Directory of Open Access Journals (Sweden)

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

Floriana GEREA

2012-08-01

217

Measurement and analysis of VoIP server performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Wang, Yusong Carl

2008-01-01

218

Chapter 11: Web-based Tools - VO Region Inventory Service  

Science.gov (United States)

As the size and number of datasets available through the VO grows, it becomes increasingly critical to have services that aid in locating and characterizing data pertinent to a particular scientific problem. At the same time, this same increase makes that goal more and more difficult to achieve. With a small number of datasets, it is feasible to simply retrieve the data itself (as the NVO DataScope service does). At intermediate scales, "count" DBMS searches (searches of the actual datasets which return record counts rather than full data subsets) sent to each data provider will work. However, neither of these approaches scale as the number of datasets expands into the hundreds or thousands. Dealing with the same problem internally, IRSA developed a compact and extremely fast scheme for determining source counts for positional catalogs (and in some cases image metadata) over arbitrarily large regions for multiple catalogs in a fraction of a second. To show applicability to the VO in general, this service has been extended with indices for all 4000+ catalogs in CDS Vizier (essentially all published catalogs and source tables). In this chapter, we will briefly describe the architecture of this service, and then describe how this can be used in a distributed system to retrieve rapid inventories of all VO holdings in a way that places an insignificant load on any data supplier. Further, we show and this tool can be used in conjunction with VO Registries and catalog services to zero in on those datasets that are appropriate to the user's needs. The initial implementation of this service consolidates custom binary index file structures (external to any DBMS and therefore portable) at a single site to minimize search times and implements the search interface as a simple CGI program. However, the architecture is amenable to distribution. The next phase of development will focus on metadata harvesting from data archives through a standard program interface and distribution of the search processing across multiple service providers for redundancy and parallelization.

Good, J. C.

219

Synthesis and properties of the double perovskites La2NiVO6, La2CoVO6, and La2CoTiO6  

International Nuclear Information System (INIS)

The double perovskites La2CoVO6, La2CoTiO6, and La2NiVO6, are described. Rietveld fitting of neutron and powder X-ray diffraction data show La2NiVO6 and La2CoVO6 to have a disordered arrangement of B-cations whereas La2CoTiO6 shows ordering of the B-cations (with ?5% Co/Ti inversion). Curie-Weiss fits to the linear region of the 1/? plots reveal Weiss temperatures of -107, -34.8, and 16.3 K for La2CoVO6, La2CoTiO6, and La2NiVO6, respectively, and magnetic transitions are observed. La2CoTiO6 prepared by our method differs from material prepared by lower-temperature routes. A simple antiferromagnetic spin model is consistent with the data for La2CoTiO6. These compounds are semiconductors with bandgaps of 0.41 (La2CoVO6), 1.02 (La2CoTiO6) and 0.45 eV (La2NiVO6). - Graphical abstract: The antiferromagnetic structure of La2CoTiO6 as prepared by high-temperature routes with spins showing the P2/m' magnetic symmetry

220

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.

 
 
 
 
221

RELATIONSHIP BETWEEN %HEART RATE RESERVE AND %VO2 RESERVE DURING ELLIPTICAL CROSSTRAINER EXERCISE  

Directory of Open Access Journals (Sweden)

Full Text Available The primary purpose of the study was to determine the relationships between %HRR vs. %VO2R and %HRR vs. %VO2max during maximal elliptical crosstrainer (ECT exercise. A secondary aim was to compare the %HRR vs. %VO2R and %HRR vs. %VO2max relationships between maximal ECT and treadmill (TM exercise. Adult subjects (n = 48 completed a maximal exercise test on the ECT, with a subgroup (N = 24 also performing a maximal exercise test on the TM. Continuous HR and VO2 data were analyzed via linear regression to determine y-intercept and slope values for %HRR vs. %VO2R and %HRR vs. %VO2max. Student t-tests were used to determine whether the mean y-intercept and slope values differed from the line of identity (y-intercept = 0, slope = 1. For each group, both the y-intercept and slope for %HRR vs. %VO2R fit the line of identity. Conversely, for all groups both the y-intercept and slope for %HRR vs. %VO2max were significantly different (p 0.05 for either y-intercept (ECT = 0.3 vs. TM = -0.3, p = 0.435 or slope (ECT = 1.01 vs. TM = 1.00, p = 0.079 values. In agreement with previous research on TM and cycle exercise, it was found that %HRR is more closely aligned with %VO2R, rather than %VO2max during ECT exercise. Additionally, it was found that the regressions of %HRR vs. %VO2R and %HRR vs. %VO2max were equivalent between the ECT and TM

Lance C. Dalleck

2006-12-01

222

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

Science.gov (United States)

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

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

2013-11-01

223

Možnosti koriš?enja naravnih energetskih virov v Pomurju s poudarkom na ekonomski upravi?enosti rabe son?ne energije  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Namen magistrskega dela je predstavitev obnovljivih virov energije ter prikaz možnosti njihovega izkoriš?anja v Pomurju, pri ?emer je poudarek na energiji sonca. Osrednji cilj je finan?na analiza investicije izgradnje son?ne elektrarne in son?nih kolektorjev. Raziskava ja pokazala, da prihajajo obnovljivi oziroma naravni energetski viri v Pomurju vse bolj v ospredje. Pri tem so najbolj izkoriš?ene son?na energija, biomasa ter geotermalna energija, medtem ko sta vetrna energija zarad...

Madz?aric?, Karla

2013-01-01

224

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.

225

Determinants of time limit at velocity corresponding to VO2max in physically active individuals  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of the present study was to determine the relationship between time limit (Tlim at VO2Máx velocity (VVO2Máx and the variables VO2Máx, VVO2Máx, running economy (RE, ventilatory threshold (VT, strength test (9-10 maximum repetitions, velocity at maximal anaerobic running test (VMART, vertical jump test and body fat percentage. The sample was composed of 18 male volunteers, aged between 18 and 45 years old, non-athletes, but physically active. The study was carried out during fi ve visits, on non-consecutive days and at approximately the same time each day: visit 1 - signature of informed consent form, medical history, anthropometric assessment, aerobic power test and familiarization with Tlim test; visit 2 - RE test and Tlim test; visit 3 - familiarization with VMART test; visit 4 - familiarization with vertical jump and 9-10 maximum repetition tests and VMART test; visit 5 - vertical jump and 9-10 maximum repetition tests. Low (r = 0.220 to – 0.359 and non-significant correlations (p = 0.281 to 0.935 were observed between Tlim and the selected variables, characterizing the low predictive value of Tlim for the sample studied. Thus, and because of the considerable inter-individual variability in Tlim, no variable was identified that was capable of satisfactorily predicting Tlim. Resumo O objetivo do presente estudo foi determinar a relação do tempo limite (Tlim na velocidade do VO2Máx (VVO2Máx com as variáveis VO2Máx, VVO2Máx, economia de corrida (EC, limiar ventilatório (LV, força isotônica (determinada pelo teste de 9-10 RM, velocidade no teste máximo de corrida anaeróbica (VMART, impulsão vertical e percentual de gordura (%G . A amostra foi composta por 18 voluntários do sexo masculino, com idade entre 18 e 45 anos, não atletas, regularmente ativos. O estudo foi realizado em cinco visitas, em dias não consecutivos e aproximadamente no mesmo horário, compostas de: visita 1 - assinatura do termo de consentimento, anamnese, avaliação antropométrica, teste de potência aeróbia e familiarização ao teste de Tlim; visita 2 - teste de EC e teste de Tlim; visita 3 - familiarização ao teste de VMART; visita 4 - familiarização aos testes de impulsão vertical e 9-10 RM e teste de VMART; visita 5 - testes de impulsão vertical e 9-10 RM. Foram observadas correlações baixas (r = 0,220 a - 0,359 e não significativas (p = 0,281 a 0,935 entre Tlim e as diversas variáveis selecionadas, o que caracteriza uma baixa qualidade preditiva para o TLim na amostra estudada. Neste sentido e tendo em vista a considerável variabilidade inter-indivíduos do TLim, não foi encontrada uma variável que pudesse predizê-lo satisfatoriamente.

Jefferson da Silva Novaes

2008-01-01

226

Complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO22+ and VO2+ with O-(N-?-phenyl, 2-hydroxy-benzylideneimino)benzoic acid  

International Nuclear Information System (INIS)

The dissociation constants of o-(N-?-phenyl, 2-hydroxybenzylideneimino) benzoic acid (H2BB) and stability constants of its chelates with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO22+ and VO2+ have been determined in aqueous medium (? = 0.01 M, 0.05 M and 0.1 M NaClO4) using Calvin's extension of Bjerrum's method. ?Go, ?Ho and ?So of the chelates have been evaluated using Gibbs-Helmholtz equation. The electronic and IR spectra and magnetic moments indicate octahedral stereochemistry for VO2+, Co(II), Ni(II) and Cu(II) chelates. (author)

227

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

CERN Document Server

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

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

2012-01-01

228

Facile growth of thermochromic VO2 nanostructures with greatly varied phases and morphologies.  

Science.gov (United States)

We have successfully and reproducibly synthesized a variety of novel vanadium dioxide (VO2) nanostructures, including metastable monoclinic VO2(B) nanoneedles and nanocorals, orthorhombic VO2(O) nanoparticles, and monoclinic VO2(M) nanofacets by manipulating the aging time of a facile sol-gel approach and the subsequent postannealing conditions. We envision that this previously unreported highly controlled synthesis and the resulting distinct morphologies of VO2 will not only provide a promising route for reliably selecting the phase, size, and morphology of these nanostructures, as well as achieving a fundamental understanding of their unusual temperature-dependent optical transmittance, but also facilitate the synthesis of functional VO2 nanostructures for a number of novel applications. PMID:23418945

Wang, Ying-Ting; Chen, Chun-Hua

2013-03-01

229

Biomasa de Eucalyptus nitens de 4-7 años de edad en un rodal de la X Región, Chile Biomass of 4-7 year-old Eucalyptus nitens in a stand in the X Region, Chile  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se estimó la biomasa total de una plantación de Eucalyptus nitens en una secuencia de edad de 4 a 7 años, con fertilización (X Región, 41º01’S-73º27’O), en un suelo rojo arcilloso de la serie Crucero. La biomasa del bosque en las edades de 4, 5 y 7 años fue estimada a partir del respectivo árbol de diámetro medio cuadrático; a los 6 años fue interpolada. Se obtuvieron componentes de la copa, tronco y raíces; además se midió mantillo y hojarasca. La biomasa total del rodal a...

Edith Geldres; Víctor Gerding; Schlatter, Juan E.

2006-01-01

230

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

International Nuclear Information System (INIS)

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

231

Comparative Study of VoIP over WiMax and WiFi  

Directory of Open Access Journals (Sweden)

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

M Atif Qureshi

2011-05-01

232

Optimization of thermochromic VO2 based structures with tunable thermal emissivity  

Science.gov (United States)

In this paper, we design and simulate VO2/metal multilayers to obtain a large tunability of the thermal emissivity of infrared (IR) filters in the typical mid wave IR 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.

Voti, R. Li; Larciprete, M. C.; Leahu, G.; Sibilia, C.; Bertolotti, M.

2012-08-01

233

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

Science.gov (United States)

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

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

2013-12-01

234

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.)

235

Graphene wrapped BiVO4 photocatalyst and its enhanced performance under visible light irradiation  

Science.gov (United States)

Graphene wrapped BiVO4 (GW-BiVO4) photocatalyst is successfully synthesized via facile sol-gel method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy techniques. The morphology of GW-BiVO4 looks like a human embryo embedded inside the amniotic sac. The photocatalytic performance of GW-BiVO4 for the decolorization of methylene blue is investigated. GW-BiVO4 system reveals enhanced photocatalytic activity for degradation of methylene blue in water under visible light irradiation as compare to pure BiVO4 catalyst and BiVO4 decorated on graphene sheet (GD-BiVO4). The experimental result shows that the wrapping of the graphene sheets in this composite catalyst enhances the photocatalytic performance under visible light. This enhance activity is mainly attributed to the effective quenching of the photogenerated electron-hole pairs which confirmed by photoluminescence spectra. Trapping experiments of radicals and holes were performed to detect the reactive species generated in the photocatalytic system, experimental results found that the direct hole oxidation reaction is obviously dominant during the photocatalytic reactions on the GW-BiVO4 system.

Gawande, Sandeep B.; Thakare, Sanjay R.

2012-07-01

236

Adsorption-controlled growth of BiVO4 by molecular-beam epitaxy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

237

Efficient removal rhodamine B over hydrothermally synthesized fishbone like BiVO4  

International Nuclear Information System (INIS)

Graphical abstract: - Highlights: • Fishbone like BiVO4 product was synthesized through hydrothermal method. • BiVO4 sample was characterized by various characterization technologies. • Fishbone like BiVO4 presented outstanding photocatalytic performance. - Abstract: Fishbone like BiVO4 product has been successfully synthesized by a hydrothermal method without using any surfactant or template. The pH value was found to play an important role in the formation of this morphology. The band gap of the as-prepared fishbone like BiVO4 sample was estimated to be about 2.36 eV from the onset of UV–vis diffuse reflectance spectrum (UV–vis DRS) of the photocatalyst. The as-prepared fishbone like BiVO4 sample exhibited excellent visible-light-driven photocatalytic efficiency. Over this catalyst, the 100% degradation of rhodamine B (Rh B) (0.005 mmol L?1) was obtained after visible light irradiation (? > 420 nm) for 180 min. This is much higher than that of bulk BiVO4 sample prepared by solid-state reaction. The reason for the differences in the photocatalytic activities of fishbone like BiVO4 sample and bulk BiVO4 sample was further investigated

238

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

Science.gov (United States)

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

Huang, Zhangli; Chen, Sihai; Lv, Chaohong; Huang, Ying; Lai, Jianjun

2012-11-01

239

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.

240

[Study on spectral property of phase transition of PcNi-VO2 films].  

Science.gov (United States)

Highly oriented VO2 thin films were deposited on sapphire substrate and [C8H17O]8 PcNi thin films were spin-coated onto VO2 thin films. The microstructure of VO2 thin films was studied with XRD. The phase transition was observed and the change in the optical properties of the PcNi/VO2 multilayer-films were investigated with infrared spectrometer. It was found that the mid-infrared transmittance of the complex films in the wavelength range 1.5 to 5.5 mm raised with PcNi coating. The thermochromism of PcNi/VO2 films did not changed compared with VO2 films and the transition temperature was the same as that of VO2. It can be anticipated that the optical limiting property of PcNi/VO2 films will be superior to that of VO2 thin films or PcNi thin films. PMID:18306765

Yuan, Hong-tao; Feng, Ke-cheng; Zhang, Xian-hui

2007-10-01

 
 
 
 
241

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

Directory of Open Access Journals (Sweden)

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

Paulo Roberto Santos Silva

1999-12-01

242

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

Science.gov (United States)

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

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

2011-11-01

243

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish La biomasa es el resultado de la transformación de la energía solar en energía química. El hombre a través de la historia la ha utilizado no solo para su alimentación sino también para la alimentación de sus animales. Los avances de la ciencia promovieron el desarrollo agrario basado en la revolució [...] n verde, la cual solo promueve la producción de alimentos ya sea de uso humano o animal, marginando la importancia de la biomasa como enriquecedor del recurso suelo al disponerse de los insumos necesarios para sustituir su fertilidad natural. En la actualidad la producción y conservación de la biomasa de cualquier cultivo cobra una importancia trascendente; por que ello contribuye, además, a la protección medioambiental a través de la captura de carbono. El presente trabajo tuvo como objetivo demostrar la importancia que proporciona la biomasa generalmente no alimenticia para los humanos, a fin de emplearla no solo como alimento animal, sino también como enriquecedora del recurso natural suelo. Las investigaciones realizadas en Cuba sobre el tema es pobre, aun cuando en la actualidad resulta de gran importancia encontrar variantes que permitan profundizar en la producción de biomasa en su relación con el medio ambiente. Finalmente se exponen los resultados preliminares sobre producción de biomasa a partir de la agrobiodiversidad presente en los escenarios productivos, a la vez que se reflexiona sobre la importancia del tema para futuras investigaciones. Abstract in english Biomass is the result of the transformation of solar energy into chemical energy. The man throughout history has used not only for food but also for feeding their animals. The progress of science promoted agricultural development based on the green revolution, which only promotes the production of e [...] ither food or feed, marginalizing the importance of biomass as enriching the soil resources available inputs needed to replace their fertility natural. At present the production and preservation of any crop biomass becomes transcendent importance, because it also contributes to environmental protection through carbon sequestration. This study aimed to show the importance of providing non-food biomass generally for humans to use it not only as animal feed but also as a natural resource rich soil. Research in Cuba on the subject is poor, even though today is very important to find alternatives to deepen in the production of biomass in relation to the environment. Finally, we present preliminary results on the production of biomass from agricultural biodiversity present in production scenarios, while reflecting on the important question for future research.

Anirebis, Martínez Romero; Angel, Leyva Galán.

2014-03-01

244

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Cuba | Language: Spanish Abstract in spanish La biomasa es el resultado de la transformación de la energía solar en energía química. El hombre a través de la historia la ha utilizado no solo para su alimentación sino también para la alimentación de sus animales. Los avances de la ciencia promovieron el desarrollo agrario basado en la revolució [...] n verde, la cual solo promueve la producción de alimentos ya sea de uso humano o animal, marginando la importancia de la biomasa como enriquecedor del recurso suelo al disponerse de los insumos necesarios para sustituir su fertilidad natural. En la actualidad la producción y conservación de la biomasa de cualquier cultivo cobra una importancia trascendente; por que ello contribuye, además, a la protección medioambiental a través de la captura de carbono. El presente trabajo tuvo como objetivo demostrar la importancia que proporciona la biomasa generalmente no alimenticia para los humanos, a fin de emplearla no solo como alimento animal, sino también como enriquecedora del recurso natural suelo. Las investigaciones realizadas en Cuba sobre el tema es pobre, aun cuando en la actualidad resulta de gran importancia encontrar variantes que permitan profundizar en la producción de biomasa en su relación con el medio ambiente. Finalmente se exponen los resultados preliminares sobre producción de biomasa a partir de la agrobiodiversidad presente en los escenarios productivos, a la vez que se reflexiona sobre la importancia del tema para futuras investigaciones. Abstract in english Biomass is the result of the transformation of solar energy into chemical energy. The man throughout history has used not only for food but also for feeding their animals. The progress of science promoted agricultural development based on the green revolution, which only promotes the production of e [...] ither food or feed, marginalizing the importance of biomass as enriching the soil resources available inputs needed to replace their fertility natural. At present the production and preservation of any crop biomass becomes transcendent importance, because it also contributes to environmental protection through carbon sequestration. This study aimed to show the importance of providing non-food biomass generally for humans to use it not only as animal feed but also as a natural resource rich soil. Research in Cuba on the subject is poor, even though today is very important to find alternatives to deepen in the production of biomass in relation to the environment. Finally, we present preliminary results on the production of biomass from agricultural biodiversity present in production scenarios, while reflecting on the important question for future research.

Anirebis, Martínez Romero; Angel, Leyva Galán.

245

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

Science.gov (United States)

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.

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

246

The DaCHS Multi-protocol VO Server  

Science.gov (United States)

GAVO's Data Center Helper Suite (DaCHS) is a suite of tools for publishing data to the Virtual Observatory. It implements all major VO protocols (SCS, SIAP, SSAP, TAP, OAI-PMH). The integrated management and ingestion component allow defining metadata, structure, and services once and re-use the definition throughout the publication cycle from initial metadata aquisition to registry record generation. It has been driving GAVO's data center since 2008 and is now deployed in multiple locations around the globe. This poster briefly describes the design of the system as well as a bird's-eye view of data publishing with DaCHS.

Demleitner, M.

2014-05-01

247

Giant magnetocaloric effect in antiferromagnetic DyVO4 compound  

Science.gov (United States)

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

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

2014-09-01

248

Water molecule adsorption properties on BiVO4 surface  

Science.gov (United States)

The behavior of water molecules on the (100) surface of BiVO4 has been investigated using first-principles molecular dynamics in view of the crucial role in photo catalytic activities under visible light irradiation. The simulations show that H2O molecules are adsorbed in a non-dissociated molecular form on the fivefold coordinated Bi site. The adsorption energy was estimated to be ~0.58 eV/molecule onto the Bi-exposing surface at 300 K. The band gap of the system shrinks slightly (by ~0.2 eV) upon water adsorption.

Oshikiri, M.; Boero, M.; Matsushita, A.; Ye, J.

2006-09-01

249

Bulk and electrochemical properties of BiVO4  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1992-01-01

250

Improving Quality of VoIP over WiMAX  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Real-time services such as VoIP are becoming popular and are major revenue earners for network service providers. These services are no longer confined to the wired domain and are being extended over wireless networks. Although some of the existing wireless technologies can support some low-bandwidth applications, the bandwidth demands of many multimedia applications exceed the capacity of these technologies. The IEEE 802.16-based WiMAX promises to be one of the wireless access technologies c...

Mohamed, M. A.; Zaki, F. W.; Mosbah, R. H.

2012-01-01

251

VoIP Steganography and Its Detection - A Survey  

CERN Document Server

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

Mazurczyk, Wojciech

2012-01-01

252

Analysis of VoIP Traffic with Multiple Packet Transfer  

Directory of Open Access Journals (Sweden)

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

Tara Chand, Vishal Srivastava

2012-06-01

253

IP Telephony Deploying VoIP Protocols and IMS Infrastructure  

CERN Document Server

All you need to know about deploying VoIP protocols in one comprehensive and highly practical reference - Now updated with coverage on SIP and the IMS infrastructure. This book provides a comprehensive and practical overview of the technology behind Internet Telephony (IP), providing essential information to Network Engineers, Designers, and Managers who need to understand the protocols. Furthermore, the author explores the issues involved in the migration of existing telephony infrastructure to an IP - based real time communication service. Assuming a working knowledge of IP and networking, i

Hersent, Olivier

2010-01-01

254

On optical bistability of VO2 films in selfabsorption range  

International Nuclear Information System (INIS)

Optical bistability (OB) on VO2 films in the region of a selfabsorption spectra at ?=1.3 ?m, at temperature of environment -20 - 50 deg C is observed. Films are grown up at the end of a quartz fibrons light quide by the method of pyrolysis of vanadium acetylacetonate. The fibrons - optical structure considered, based on vanadium dioxide films, possessing OB, is not at disadvantage in relation to the known materials with OB of a thermal rock by such parameters as threshold capacities and turn-off times

255

Comprehensive picture of VO2 from band theory  

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

Zhu, Zhiyong

2012-08-28

256

Dievo kaip t?vo ?vaizdis Kumrano raštuose  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dievo kaip T?vo ?vaizdis teologin?je literat?roje dažniausiai yra aptariamas pasiremiant Šventuoju Raštu. Kadangi Kumrano raštuose šia tema n?ra randama daug tiesiogini? teigini? ar aliuzij?, jie dažniausiai lieka šeš?lyje, kaip neteikiantys svarbios informacijos. Šis straipsnis kaip tik ir yra skirtas pristatyti ir aptarti visus iki šiol atrast? Kumrano rašt? tekstus, kuriuose tiesiogiai ar netiesiogiai kalbama apie Dievo t?vyst?. Visi tekstai suskirstyti ? tris grup...

Kasc?iukaitis, Arvydas

2010-01-01

257

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

Scientific Electronic Library Online (English)

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

Eunice, Guevara; Orlando, Guenni.

258

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

Directory of Open Access Journals (Sweden)

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

María J Gualtieri A

2007-12-01

259

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

Scientific Electronic Library Online (English)

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

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

260

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

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

Sánchez O. M.

2004-04-01

 
 
 
 
261

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

Scientific Electronic Library Online (English)

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

Sandra, Merayo; Ernesto J, González.

2010-06-01

262

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

Scientific Electronic Library Online (English)

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

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

2008-06-01

263

AEROBIC AND STRENGTH TRAINING RESPONSES IN THE VO2max  

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Full Text Available The strength training of produces improvements in the skeletal muscle as to the muscular hypertrophy, already the aerobic training produces an increase in him I number and in the size of the mitochondria. The objective was verifying the answers of the aerobic training and of force in the aerobic variables. The study was composed of 3 groups. The Aerobic Group (G1 that performed 6 weeks of training of aerobic, the Strength Group (G2 that did a program of 6 strength training weeks and the Group Control (GC. The evaluations of the study occurred in 2 moments: before of the training and in the week 6. We evaluate the VO2MAX, to mechanical power and the IErg. The G1 presented significant differences in all the variables analyzed, while the G2 presented significant difference in the VO2MÁX The study found an increase more marked in the aerobic instalments as answer of the aerobic training regarding the of force.

Pilar Sánchez Collado

2007-12-01

264

Cation self-diffusion in disordered VO/sub x/  

International Nuclear Information System (INIS)

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

265

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

Scientific Electronic Library Online (English)

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

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

2011-07-01

266

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

Scientific Electronic Library Online (English)

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

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

267

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  

Directory of Open Access Journals (Sweden)

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.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, commercial growing media, and V, vermicompost. The following proportions were studied (v/v: V100 (100%V; VO75-25 (75%V+25%O; VO50-50 (50%V+50%O; VO 25-75 (25%V+75%O and O100 (100%O. The inclusion of vermicompost did not improve biomass production. The treatment O100 produced more biomass and the lowest was obtained in VO25-75. On V100 treatment all plants were dead and also have showed the highest pH and particle density and conversely presented the lowest value of total pore space. Oxygenated monoterpenes predominated in the oils extracted from plants in O100 and VO25-75, contrary to what was found for non-oxygenated monoterpenes having these prevailed in VO75-25 and VO50-50. The concentration of thymol was high in the mixtures tested, particularly in VO25-75.

Nelson Lourenço

2011-07-01

268

PERSPECTIVAS DE OBTENCIÓN DE ENERGÍA RENOVABLE DE LA BIOMASA DEL ESTIÉRCOL DEL GANADO LECHERO EN LA REGIÓN CENTRO-SUR DE CHIHUAHUA  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Actualmente casi la totalidad de la energía es proporcionada por fuentes fósiles que incrementan las emisiones de gases invernadero contribuyendo al calentamiento global. Estas emisiones se pueden reducir con el uso de energía renovable producida a través de la biomasa como el estiércol del ganado. El estiércol es materia prima para la producción de electricidad y energía térmica. La digestión anaeróbica de los desechos puede reducir las emisiones por la captura de metano, un gas i...

Bertha Alicia Rivas Lucero; Iga Avila, Gabriel Zu Fau F.; Enz Solis, Jorge Iram Su E.; Sergio Guerrero Morales; Armando Segovia Lerma; Morales Morales, Hugo A.

2012-01-01

269

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Anguiano, J. M.; Aguirre, J.; Palma, J. M.

2013-01-01

270

Potentiometric parameters of a PVC-NaV6O15 - graphite electrode  

International Nuclear Information System (INIS)

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

271

Which Are The Best VO2 Sampling Intervals to Characterize Low to Severe Swimming Intensities?  

Science.gov (United States)

Cardiorespiratory response in swimming has been used to better understand aerobic performance, especially by assessing oxygen uptake (VO2). The current study aimed to compare different VO2 time-averaging intervals throughout low to severe swimming intensities, hypothesizing that VO2 values are similar for different time averages at low to moderate and heavy swimming intensities, but not for the severe domain. 20 male trained swimmers completed an incremental protocol of 7×200?m until exhaustion (0.05?m/s increments and 30?s intervals). VO2 was measured by a portable gas analyser connected to a snorkel system. 6 time average intervals (breath-by-breath, 5, 10, 15, 20 and 30?s) were compared for all the protocol steps. Breath-by-breath and 5?s average exhibited higher VO2 values than averages?10?s for all swimming intensities (P?0.02; partial ?(2)?0.28). VO2 values did not differ between 10, 15, 20 and 30?s averages throughout the incremental protocol (P>0.05; partial ?(2)?0.05). Furthermore, 10 and 15?s averages showed the lowest VO2 mean difference (0.19?mL(?·?)kg(-1?·?)min(-1)). For the 6 time average intervals analysed, 10 and 15?s averages were those that showed the lowest changes on VO2 values. We recommended the use of 10 and 15?s time averaging intervals to determine relevant respiratory gas exchange parameters along a large spectrum of swimming intensities. PMID:24892654

de Jesus, K; Guidetti, L; de Jesus, K; Vilas-Boas, J P; Baldari, C; Fernandes, R J

2014-11-01

272

A first transition series pseudotetrahedral oxynitride anion: synthesis and characterization of Ba(2)VO(3)N.  

Science.gov (United States)

Ammonolysis of reactive oxide precursors affords the vanadium(V) phase Ba(2)VO(3)N that is shown by X-ray and neutron powder diffraction and Raman spectroscopy to contain pseudotetrahedral VO(3)N(4-) anions. This is the first example of such species for the first transition series metals. PMID:11916418

Clarke, Simon J; Chalker, Paul R; Holman, Jasper; Michie, Charles W; Puyet, Matthieu; Rosseinsky, Matthew J

2002-04-01

273

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

Science.gov (United States)

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

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

2007-01-01

274

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

Science.gov (United States)

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

Schembre, Susan M.; Riebe, Deborah A.

2011-01-01

275

Effect of Toe Clips During Bicycle Ergometry on VO2 max.  

Science.gov (United States)

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

Moffat, Roger S.; Sparling, Phillip B.

1985-01-01

276

Switchable vanadium dioxide (VO2) metamaterials fabricated from tungsten doped vanadia-based colloidal nanocrystals  

Science.gov (United States)

We report the fabrication of thermochromic VO2-based metamaterials using solution-processable colloidal nanocrystals. Vanadium-based nanoparticles are prepared through a non-hydrolytic reaction, resulting in stable colloidal dispersions in solution. Thermochromic nanocrystalline VO2 thin-films are prepared via rapid thermal annealing of colloidal nanoparticles coated on a variety of substrates. Nanostructured VO2 can be patterned over large areas by nanoimprint lithography. Precise control of tungsten (W) doping concentration in colloidal nanoparticles enables tuning of the phase transition temperature of the nanocrystalline VO2 thin-films. W-doped VO2 films display a sharp temperature dependent phase transition, similar to the undoped VO2 film, but at lower temperatures tunable with the doping level. By sequential coating of doped VO2 with different doping concentrations, we fabricate ?smart? multi-layered VO2 films displaying multiple phase transition temperatures within a single structure, allowing for dynamic modulation of the metal-dielectric layered structure. The optical properties programmed into the layered structure are switchable with temperature, which provides additional degrees of freedom to design tunable optical metamaterials.

Paik, Taejong; Hong, Sung-Hoon; Gordon, Thomas; Gaulding, Ashley; Kagan, Cherie; Murray, Christopher

2013-03-01

277

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

International Nuclear Information System (INIS)

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

278

Adsorption-controlled growth of BiVO4 by molecular-beam epitaxy  

Science.gov (United States)

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

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

2013-10-01

279

Adsorption-controlled growth of BiVO4 by molecular-beam epitaxy  

Directory of Open Access Journals (Sweden)

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

S. Stoughton

2013-10-01

280

Synthesis and Characterization of Highly Visible―light Active Monoclinic Mesoporous BiVO4  

Directory of Open Access Journals (Sweden)

Full Text Available Ordered nanocrystalline mesoporous BiVO4 with pure phase was successfully synthesized at 550¡æ via nanocasting using cubic MCM―48 molecular sieves as hard template. The long―range ordered mesostructure was characterized by XRD, TEM, BET as well as UV―Vis spectrophotometer. Compared with the BiVO4 synthesized by conventional hydrothermal method, the nanocasting mesoporous BiVO4 has the average pore diameter of 16.8nm, pore volume of 0.1 cm3/g and specific surface area up to 22.9 m2/g. The structure decreases the recombination of optical excitation electrons and holes efficiently, so the mesoporous BiVO4 has an excellent photocatalytic activity in the visible light region. As a result, the photocatalytic efficiency of mesoporous BiVO4 for xanthate in 90min reaches 78%.

XIAO Qi, GAO Lan, ZHANG Xiang

2011-12-01

 
 
 
 
281

Preparation of Au-BiVO4 heterogeneous nanostructures as highly efficient visible-light photocatalysts.  

Science.gov (United States)

Au-BiVO(4) heterogeneous nanostructures have been successfully prepared through in situ growth of gold nanoparticles on BiVO(4) microtubes and nanosheets via a cysteine-linking strategy. The experimental results reveal that these Au-BiVO(4) heterogeneous nanostructures exhibit much higher visible-light photocatalytic activities than the individual BiVO(4) microtubes and nanosheets for both dye degradation and water oxidation. The enhanced photocatalytic efficiencies are attributed to the charge transfer from BiVO(4) to the attached gold nanoparticles as well as their surface plasmon resonance (SPR) absorption. These new heteronanostructures are expected to show considerable potential applications in solar-driven wastewater treatment and water splitting. PMID:22141400

Cao, Shao-Wen; Yin, Zhen; Barber, James; Boey, Freddy Y C; Loo, Say Chye Joachim; Xue, Can

2012-01-01

282

Synergistic effects of codopants on photocatalytic O2 evolution in BiVO4  

Science.gov (United States)

The electronic structures and related properties of N- and M (M = Cr, Mo) doped BiVO4 are investigated by means of first-principles calculations. The synergistic codoping effects of N and M on photocatalytic O2 evolution in BiVO4 are studied. Our results demonstrate that the band gap of N/Cr- and N/Mo-codoped BiVO4 are reduced by about 0.34 and 0.15 eV compared with undoped system, respectively, with the redox potential still locating at a level suitable for O2 evolution, which results in the response of visible light enhancement and the production of O2 evolution improvement of BiVO4 under visible light. The energy calculations indicate that the introduction of M in BiVO4 favors incorporation of N and the codoped material is more stable.

Lai, Kangrong; Zhu, Yingtao; Lu, Jibao; Dai, Ying; Huang, Baibiao

2013-10-01

283

Self-Assembly and Horizontal Orientation Growth of VO2 Nanowires  

Science.gov (United States)

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.

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

2014-06-01

284

Thermochromic properties of VO2 thin film on SiNx buffered glass substrate  

Science.gov (United States)

VO2 thin films were deposited on soda lime glass substrates with silicon nitride sodium-diffusion barrier layer as diffusion barrier, in order to investigate the effect of sodium ion diffusion on the formation of VO2. SiNx layers with thicknesses over 30 nm were found to successfully prevent sodium ion diffusion in VO2 thin film and also contribute to the formation of VO2 thin film, which was confirmed by XRD spectra and XPS measurements. The change of infrared transmittance at 2500 nm wavelength with temperature change from room temperature to 80 °C was increased significantly, and the optical hysteresis width of the sample decreased by almost 6 K as well. The results suggest that applying diffusion barrier can improve the thermochromic properties of the VO2 films for energy-saving smart coatings, and silicon nitride can be one of the effective materials to prevent sodium ion diffusion.

Koo, Hyun; You, HyunWoo; Ko, Kyeong-Eun; Kwon, O.-Jong; Chang, Se-Hong; Park, Chan

2013-07-01

285

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

CERN Document Server

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

Wang, Hao; Wang, Liping

2014-01-01

286

Doping properties of monoclinic BiVO4 studied by first-principles density-functional theory  

Science.gov (United States)

The intrinsic and extrinsic doping properties of BiVO4, i.e., the formation energies and transition energy levels of defects and impurities, have been studied systematically by first-principles density-functional theory. We find that for doping caused by intrinsic defects, O vacancies are shallow donors and Bi vacancies are shallow acceptors. However, these defects compensate each other and can only lead to moderate n-type and p-type conductivities at Bi-rich and O-rich growth conditions, respectively. To obtain BiVO4 with high n-type and p-type conductivities, which are required for forming Ohmic contacts, extrinsic doping using foreign impurities is necessary. Our results reveal that Sr, Ca, Na, and K atoms on Bi sites are very shallow acceptors and have rather low formation energies. The calculated Fermi-level pinning positions predict that doping of these impurities under oxygen-rich growth conditions should result in outstanding p-type conductivity. Substitutional Mo and W atoms on V sites are very shallow donors and have very low formation energies. Fermi-level pinning position calculations expect the doping of Mo and W under oxygen-poor growth conditions to produce excellent n-type conductivity. Also discussed is the dependence of formation energies and transition energies of defects on the atomic size and atomic chemical potential trends.

Yin, Wan-Jian; Wei, Su-Huai; Al-Jassim, Mowafak M.; Turner, John; Yan, Yanfa

2011-04-01

287

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

Directory of Open Access Journals (Sweden)

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

Pardo Luis C

2006-03-01

288

Carbono en biomasa microbiana y carbono soluble como indicadores de calidad de Vertisoles cultivados con caña azucarera  

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Full Text Available El objetivo del presente estudio fue identificar propiedades biológicas, químicas y físicas del suelo, como el carbono de la biomasa microbiana (Cbio, el carbono orgánico soluble (COS, el pH, la materia orgánica (MO, la capacidad de intercambio catiónico (CIC y la densidad parente (Dap, como indicadores de calidad del cambio de uso del suelo de selva a cultivo de caña de azúcar en la Chontalpa, Tabasco. Se muestreó un Vertisol de selva y cuatro Vertisoles cultivados con caña de azúcar durante cinco, 10 y 20 y más de 30 años. Se encontró que ocurren cambios significativos en las propiedades del suelo cuando una selva se transforma en suelo cultivado con caña de azúcar. El Cbio, el COS y la MO disminuyeron conforme aumentó el tiempo dedicado al cultivo. El cambio en las propiedades del suelo de los diferentes sitios se atribuye al manejo agrícola que año con año se lleva a cabo en el suelo, así como a la falta de prácticas agronómicas que contribuyan a conservar la fertilidad del suelo cañero.

Liliana Armida-Alcudia

2005-01-01

289

Prepaid and Postpaid VoIP Service Enhancements and Hybrid Network Performance Measurement  

Directory of Open Access Journals (Sweden)

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

Mohd Nazri Ismail

2006-01-01

290

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

291

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

Scientific Electronic Library Online (English)

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

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

292

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

Scientific Electronic Library Online (English)

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

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

293

Evaluation of the American College of Sports Medicine submaximal treadmill running test for predicting VO2max.  

Science.gov (United States)

The purpose of this study was to assess the validity of the American College of Sports Medicine's (ACSM's) submaximal treadmill running test in predicting VO2max. Twenty-one moderately well-trained men aged 18-34 years performed 1 maximal treadmill test to determine maximal oxygen uptake (M VO2max) and 2 submaximal treadmill tests using 4 stages of continuous submaximal exercise. Estimated VO2max was predicted by extrapolation to age-predicted maximal heart rate (HRmax) and calculated in 2 ways: using data from all submaximal stages between 110 b·min(-1) and 85% HRmax (P VO2max-All), and using data from the last 2 stages only (P VO2max-2). The measured VO2max was overestimated by 3% on average for the group but was not significantly different to predicted VO2max (1-way analysis of variance [ANOVA] p = 0.695; M VO2max = 53.01 ± 5.38; P VO2max-All = 54.27 ± 7.16; P VO2max-2 = 54.99 ± 7.69 ml·kg(-1)·min(-1)), although M VO2max was not overestimated in all the participants--it was underestimated in 30% of observations. Pearson's correlation, standard error of estimate (SEE), and total error (E) between measured and predicted VO2max were r = 0.646, 4.35, 4.08 ml·kg(-1)·min(-1) (P VO2max-All) and r = 0.642, 4.21, 3.98 ml·kg(-1)·min(-1) (P VO2max-2) indicating that the accuracy in prediction (error) was very similar whether using P VO2max-All or P VO2max-2, with up to 70% of the participants predicted scores within 1 SEE (?4 ml·kg(-1)·min(-1)) of M VO2max. In conclusion, the ACSM equation provides a reasonably good estimation of VO2max with no difference in predictive accuracy between P VO2max-2 and P VO2max-All, and hence, either approach may be equally useful in tracking an individual's aerobic fitness over time. However, if a precise knowledge of VO2max is required, then it is recommended that this be measured directly. PMID:22262016

Marsh, Clare E

2012-02-01

294

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)

Full Text Available SciELO Costa Rica | Language: English Abstract in spanish 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

Milena Fermina, Rosenfield; Alexandre F., Souza.

2014-03-01

295

¿Afectan los aclareos la acumulación de biomasa aérea en una plantación de Pinus patula? / Does thinning affect aboveground biomass acummulation in a Pinus patula plantation?  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish El aclareo puede modificar la distribución y cantidad de biomasa aérea en función del tiempo de respuesta y de las condiciones de crecimiento. En este estudio se analizó el efecto de aclareos en la distribución y contenido de biomasa aérea acumulada de Pinus patula mediante muestreos destructivos de [...] 30 árboles en 2009, después de estar sometidos a diferentes intensidades de aclareo desde el 2004, más un testigo intacto. La eliminación entre 40 y 69 % de la densidad inicial de plantación afectó significativamente (p ? 0.05) la cantidad y distribución de biomasa foliar y la cantidad de madera con corteza en el fuste a nivel de árbol individual (pero no por ha) en algunos componentes del árbol. Las intensidades altas de aclareo (65.3 y 68.7 %>) y las respectivas densidades residuales bajas generaron la mayor acumulación de biomasa foliar (5.4 kg árbol-1 y 8.0 t ha-1), que superaron (p?0.05) al testigo sin aclareo (1.5 kg árbol-1). En la biomasa de madera con corteza del fuste los árboles con aclareo también superaron (p?0.05) al testigo (98 fs. 35.3 kg árbol-1). Sin embargo, la acumulación de biomasa por unidad de superficie fue similar entre ambas condiciones, debido a la excesiva densidad residual del testigo; lo mismo ocurrió en la biomasa total de ramas y en la distribución en el fuste. Abstract in english Thinning may modify distribution and amount of aboveground biomass according to time of response and growth conditions. In this study, the effect of thinning on distribution and accumulated aboveground biomass content of Pinus patula was analyzed in 2009 through destructive samplings of 30 trees, af [...] ter having been subjected to different thinning intensities since 2004, plus an intact control. Elimination between 40 and 69 % of initial plantation density significantly affected (p?0.05) quantity and distribution of leaf biomass and the amount of timber with bark on the stem at individual tree level in some tree components (but not by ha). The high thinning intensity (65.3 and 68.7 %) and respective low residual density generated the largest accumulation of foliar biomass (5.4 kg tree-1 and 8.0 t ha-1), surpassing (p?0.05) the control without thinning (1.5 kg tree-1). In timber biomass with stem bark, trees with thinning also surpassed (p?0.05) the control (98 fs. 35.3 kg tree-1). However, biomass accumulation per unit was similar between both conditions, due to excessive residual density of the control; the same occurred in total branch biomass and in distribution on the stem.

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

2011-09-01

296

Zircon to monazite phase transition in CeVO4  

CERN Document Server

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

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

2011-01-01

297

Enhanced nuclear acoustic resonance in HoVO4  

International Nuclear Information System (INIS)

A strong resonant absorption is observed for longitudinal acoustic waves at 800 MHz, propagated along the [100] axis of a single crystal of the enhanced nuclear paramagnet HoVO4, in the presence of a magnetic field in the (001) plane. The strength of the resonant absorption is inversely proportional to the absolute temperature T, with a power attenuation coefficient of 4.5(2) x 102 T-1 m-1. From this and the measured velocity of 6.52(6) x 103m s-1, a rate of 10-3 T s-1 is deduced for the intrinsic direct spin-lattice relaxation process. This is orders of magnitude smaller than the Orbach rate (10+4 to 10+5 s-1 at T = 3 K), and slower than the measured rate at 0.2 K, that must therefore be attributed to the presence of paramagnetic impurities. (author)

298

Mössbauer and susceptibility studies of FeMoVO7  

Science.gov (United States)

The oxidic phase FeMoVO7 of the Fe2O3-V2O5-MoO3 system has been synthesized. Susceptibility measurements from 4.2 K to room temperature display an antiferromagnetic behaviour with an effective magnetic moment of 5.80 ? b . This value, and the measured Mössbauer isomer shift of 0.40±0.02 mm/s, are characteristic of high-spin Fe(III). The low T n value of 15 K suggests a weak interaction among the Fe-O polyhedra. The relative small QS=0.28±0.02 mm/s found in this compound shows that the Fe-O polyhedra symmetry is close to octahedral and almost undistorted.

Goya, G. F.; Mercader, R. C.; Vassallo, M. B.; Botto, I. L.; Sáez Puche, R.

1994-12-01

299

Influence of dimensionality on phase transition in VO2 nanocrystals  

Directory of Open Access Journals (Sweden)

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

Blagojevi? V.A.

2013-01-01

300

Active terahertz nanoantennas based on VO2 phase transition.  

Science.gov (United States)

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

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

 
 
 
 
301

Efficient High Power Ho,Tm:GdVO4 Laser  

International Nuclear Information System (INIS)

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

302

A structured approach to VO reconfigurations through Policies  

CERN Document Server

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

Reiff-Marganiec, Stephan

2012-01-01

303

Optimization of optical properties of thermochromic VO2 films  

International Nuclear Information System (INIS)

Vanadium dioxide shows a thermally induced semiconductor-metal phase transition at 68 C. Especially the related change in the optical properties enables many applications in infra-red light (IR)-switching or bolometric devices or as ''intelligent''energy conserving window coating. For certain applications the transition temperature has to be tuned and the transmittance in the visible and infra-red spectral range should be optimized. An appropriate way to achieve the required properties is doping. We studied a series of VO2 layers prepared by radio frequency sputtering and doped by an additional solid in the target or by a reactive gas used in the deposition process. The optical switching properties were evaluated from wavelength and temperature dependent transmission measurements. The crystal structure of the films was studied by X-ray diffraction (XRD) and the composition of the layers was determined by energy-dispersive X-ray analysis (EDX) and secondary ion mass spectroscopy (SIMS)

304

Shape controllable synthesis and luminescence properties of LuVO4:Ln3+ (Ln3+ = Eu, Sm, and Dy) nano/microstructure.  

Science.gov (United States)

The LuVO4:Ln3+ (Ln3+ = Eu, Dy, and Sm) nano/microcrystals with different shapes were synthesized through a simple hydrothermal route assisted by trisodium citrate (Na3Cit). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), and cathodoluminescence (CL) spectra were employed to characterize the samples. A series of controlled experiments indicate that the shape and size of as-prepared architectures can be tuned effectively by controlling the reaction conditions, such as vanadium sources, different organic additives, the content of organic additive trisodium citrate (Cit(3-)), and reaction time. It is found that Cit(3-) as a ligand and shape modifier has the dynamic effect by adjusting the growth rate of different facets under different experimental conditions, resulting in the formation of various geometries of the final products. The possible formation mechanisms for products with diverse architectures have been presented in detail. The Ln3+ ions doped LuVO4 sample exhibit respective bright red, orange and green-yellow luminescence of Eu3+, Sm3+, and Dy3+ under ultraviolet excitation and low-voltage electron beam excitation. The ability to generate LuVO4 nano/microstructures with diverse shapes, and multicolor emission provides a great opportunity for systematically evaluating their luminescence properties, as well as fully exploring their applications in many types of color display fields. PMID:23421218

Gao, Yu; Feng, Bin; Fang, Qinghong; Gong, Jian

2012-11-01

305

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-15

306

Inducing polarity in [VO3]nn- chain compounds using asymmetric hydrogen-bonding networks  

Science.gov (United States)

1,4-Bis(3-aminopropyl)piperazine, (R)-3-aminopiperidine and (S)-3-aminopiperidine were used in the syntheses of [C10H26N4][VO3]2·2H2O, [(R)-C5H14N2][VO3]2 and [(S)-C5H14N2][VO3]2, which all contain similar [VO3]nn- chains. Inversion symmetry within the 1,4-bis(3-aminopropyl)piperazine allows for crystallization of [C10H26N4][VO3]2·2H2O in a centrosymmetric space group, while the use of enantiomerically pure sources of either (R)-3-aminopiperidine or (S)-3-aminopiperidine forces crystallographic noncentrosymmetry. Moreover, asymmetry in the hydrogen-bonding networks between the metavanadate chains and either [(R)-3-aminopiperidineH2]2+ or [(S)-3-aminopiperidineH2]2+ cations directs alignment of the chains and crystallization in a polar space group (C2, no. 5). Component and net dipole moments were calculated using iterative-Hirshfeld partial atomic charges. [(R)-C5H14N2][VO3]2 and [(S)-C5H14N2][VO3]2 both display type 1 phase-matching capabilities and exhibit second harmonic generation activities of ˜140×?-SiO2.

Smith, Matthew D.; Blau, Samuel M.; Chang, Kelvin B.; Tran, Thanh Thao; Zeller, Matthias; Halasyamani, P. Shiv; Schrier, Joshua; Norquist, Alexander J.

2012-11-01

307

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

Science.gov (United States)

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

Lu, Jiwei

2008-10-01

308

BiVO4–graphene catalyst and its high photocatalytic performance under visible light irradiation  

International Nuclear Information System (INIS)

Highlights: ? A facile strategy is designed to deposit leaf-like BiVO4 lamellas on graphene sheet. ? Graphene oxide is reduced to graphene in the hydrothermal reaction process. ? BiVO4–graphene system shows high catalytic effects under visible light irradiation. - Abstract: A BiVO4–graphene photocatalyst was prepared by a facile one-step hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM) techniques. The results show that the graphene sheets in this catalyst are exfoliated and decorated by leaf-like BiVO4 lamellas. In comparison with the pure BiVO4 catalyst, the BiVO4–graphene system reveals much higher photocatalytic activity for degradation of methyl orange (MO), methylene blue (MB), Rhodamine B (RhB) and active black BL-G in water under visible light irradiation due to the concerted effects of BiVO4 and graphene sheets or their integrated properties.

309

Effects of erythrocyte infusion on VO2max at high altitude  

DEFF Research Database (Denmark)

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.

Young, Jette Feveile; Sawka, M N

1996-01-01

310

Coprecipitation synthesis and negative thermal expansion of NbVO5.  

Science.gov (United States)

We develop a coprecipitation synthesis route to prepare NbVO(5) with simple oxide Nb(2)O(5) and NH(4)VO(3) as starting materials. No metal alkoxide or organometallic substance was used in the process. Nano-crystal NbVO(5) was obtained by calcination of the coprecipitates at 550 °C for 2 h. DSC/TG and XRD investigations indicate that the target compound NbVO(5) is completely formed up to 504.5 °C and is thermally stable below 658 °C. Rietveld XRD refinements give an orthorhombic structure with space group Pnma and lattice parameters, a=11.8453(2), b=5.5126(3) and c=6.9212(2) Å, respectively. In particular, HTXRD determinations show a negative thermal expansion in NbVO(5) with a TEC of -6.63 × 10(-6) °C(-1) in the temperature range of RT-600 °C. This fact is ascribed to the tilting of NbO(6) octahedra and VO(4) tetrahedra in the flexible framework structure. The present synthesis route is facile and easy to be extended to prepare analogues such as TaVO(5), etc. PMID:21336369

Wang, Jinrui; Deng, Jinxia; Yu, Ranbo; Chen, Jun; Xing, Xianran

2011-04-01

311

Reinvestigation of the synthesis of LiFeVO{sub 4}  

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} We reinvestigated the synthesis of the LiFeVO{sub 4} compound. {yields} We demonstrate that the recently reported LiFeVO{sub 4} phase is not a pure phase. {yields} We proved by Rietveld refinement that LiFeVO{sub 4} is a mixture ofLiVO{sub 3} and Fe{sub 2}O{sub 3}. {yields} We noticed some attempts to fraud (modification of the powder pattern) . - Abstract: The synthesis of LiFeVO{sub 4} composition has been performed in air starting from Li{sub 2}CO{sub 3}, Fe{sub 2}O{sub 3}, and V{sub 2}O{sub 5} and using the standard solid-state reaction route reported by Refs. . Identical X-ray diffraction pattern has been obtained, however our careful analysis with MDI Jade 5.0 software does not agree with previously reported pure LiFeVO{sub 4} samples. The powder pattern has been perfectly indexed using the single crystal data of LiVO{sub 3} (C2/c, a = 10.16718 A, b = 8.415725 A, c = 5.884155 A and {beta} = 110.489{sup o}) and {alpha}-Fe{sub 2}O{sub 3} (R-3c, a = 5.035 A, c = 13.75 A).

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

2011-07-15

312

Size-dependent magnetic properties of VO2 nanocrystals dispersed in a silica matrix  

International Nuclear Information System (INIS)

Magnetic nanocrystalline VO2 particles have been successfully synthesized in a silica glass matrix by the sol-gel method at calcination temperatures of 700 0C and above. The presence of small quantities of diamagnetic V2O5 nanocrystals in glass samples calcined at ?800 0C has been confirmed. The thermal behavior of magnetization (zero-field-cooled and field-cooled) and magnetic hysteresis of VO2 nanocrystals in the 10-300 K temperature interval have demonstrated that the VO2 nanocrystals present in these glasses display superparamagnetic-ferromagnetic transition at low temperatures. X-band electron paramagnetic resonance (EPR) spectra of VO2 nanoparticles have depicted broad symmetric lines [?Hpp?104 mT at room temperature (RT) and 250 mT at liquid nitrogen temperature (LNT)]. The increase in EPR line intensity on going from RT to LNT suggests that VO2 nanocrystals have undergone ferromagnetic-like ordering in the temperature interval RT-77 K. The presence of small numbers of isolated VO2+ ions in the SiO2 matrix has also been confirmed from EPR studies. From EPR and optical spectral studies it has been shown that the VO2+ ion has square pyramidal conformation with tetragonal compression having C4v symmetry. It is established that the in-plane ? bonding and out-of-plane ? bonding are predominantly ionic in natding are predominantly ionic in nature

313

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Jia, Qingxin; Iwashina, Katsuya; Kudo, Akihiko

2012-01-01

314

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

Energy Technology Data Exchange (ETDEWEB)

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

Kouchri, Farrokh Mohammadzadeh

2012-11-06

315

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

Directory of Open Access Journals (Sweden)

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

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

2012-10-01

316

Estimated V(O2)max from the rockport walk test on a nonmotorized curved treadmill.  

Science.gov (United States)

The Rockport Walk Test (RWT) is a 1-mile walk used to estimate the maximal volume of oxygen uptake (V(O2)max). The purpose of this study was to validate the RWT on a nonmotorized curved treadmill (CT). Twenty-three healthy adults (10 females; 19-44 years old) participated. One trial of the RWT was performed on a measured indoor track (RWTO) and another on the CT (RWTC) on different days in randomized order. Heart rate (HR) and completion time were used to calculate V(O2)max using 6 different general and gender specific equations from previous research. Subjects also performed a treadmill graded exercise test (GXT), which was used as the criterion measure for V(O2)max. Completion times and HR between the 2 RWT were compared using dependent t-tests. Estimated V(O2)max values were compared between the RWTC, RWTO, and GXT through repeated measures analysis of variance, Pearson's correlations (r), and Bland-Altman's plots. There was no difference between completion times for the RWTO and RWTC but HRs were significantly higher with RWTC. When the same equation was applied to the RWTO and RWTC, there were no similar results. All V(O2)max estimations were different from observed V(O2)max except for the estimation from the relative general Kline et al. equation on the RWTO. Despite high correlations (r = 0.75-0.91), the RWTC underestimated V(O2)max. The RWTC underestimates V(O2)max but may be beneficial if a new equation were created specifically for the CT. With appropriate equations for the CT, the RWTC would provide an alternate form of V(O2)max testing. PMID:23478472

Seneli, Rhiannon M; Ebersole, Kyle T; O?Connor, Kristian M; Snyder, Ann C

2013-12-01

317

Lithium-inserted vanadium dioxide (LixVO2) thin films  

Science.gov (United States)

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

Khan, Mohammad S. R.

1996-04-01

318

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

Scientific Electronic Library Online (English)

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

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

2011-12-01

319

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

Directory of Open Access Journals (Sweden)

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

Edgar J. Morales-Rosales

2006-01-01

320

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

Scientific Electronic Library Online (English)

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

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

 
 
 
 
321

Fermi Surface of 3d^1 Perovskite CaVO3 Near the Mott Transition  

CERN Document Server

We present a detailed de Haas van Alphen effect study of the perovskite CaVO3, offering an unprecedented test of electronic structure calculations in a 3d transition metal oxide. Our experimental and calculated Fermi surfaces are in good agreement -- but only if we ignore large orthorhombic distortions of the cubic perovskite structure. Subtle discrepancies may shed light on an apparent conflict between the low energy properties of CaVO3, which are those of a simple metal, and high energy probes which reveal strong correlations that place CaVO3 on the verge of a metal-insulator transition.

Inoue, I H; Hase, I; Julian, S R

2002-01-01

322

An experimental analysis of Joost peer-to-peer VoD service  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Despite strong interest in peer-to-peer (P2P) Video-on-Demand (VoD) services, existing studies mostly focus on peer-to-peer or overlay protocol design based on simulations under various topological constraints. We believe experimental studies on a real-life P2P VoD system will provide valuable information to ISPs, network administrators, and content owners. In this paper we present a comprehensive analytical and experimental study on Joost, one of the first commercial P2P Vo...

Lei, Jun; Shi, Lei; Fu, Xiaoming

2009-01-01

323

Thin-film VO2 submillimeter-wave modulators and polarizers  

International Nuclear Information System (INIS)

Submillimeter-wave modulators and switchable polarizers have been fabricated from VO2 thin films deposited on sapphire substrates. By passing electric current pulses through elements made from these films, the films can be thermally cycled through the insulator-to-metal transition that occurs in VO2 at about 65 degreeC. In the insulating state, the films are found to have negligible effect on the transmission at submillimeter wavelengths, while above the phase transition the transmission is strongly reduced by the free-electron effects characteristic of a metal. Other possible applications of such switchable VO2 elements include variable bandpass filters and diffraction grating beam-steering devices

324

Optimal Streaming Protocol for VoD Using Clients' Residual Bandwidth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A true VoD system has tremendous demand in the market. The existing VoD system does not cater the needs and demands of the market. The major problem in the VoD system is serving of clients with expected QoS is difficult. In this paper, we proposed a protocol and algorithm that chains the proxy servers and subscribed clients. Our objective is to send one server stream and this stream should be served to N asynchronous clients. The server bandwidth is scarcity and on the client uplink bandwidth...

Ashok Kumar, R.; Hareesh, K.; Ganesan, K.; Manjaiah, D. H.

2010-01-01

325

Impact of VoIP and QoS on Open and Distance Learning  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2006-01-01

326

Hydrothermal synthesis of VO2 (B) nanostructures and application in aqueous Li-ion battery  

International Nuclear Information System (INIS)

VO2 (B), one of metastable phases of vanadium dioxide, should be a promising candidate cathode material to be applied in aqueous Li-ion battery owing to its proper electrode potential and layered structure. In this study, three different morphologies of the VO2 (B): nanorods, nanoflakes and nanoflowers were synthesized via one-step hydrothermal process. Electrochemical behaviors of the three samples were evaluated by cyclic voltammetry. The results showed that flower-like VO2 (B) had the best capacity retention behavior, and the largest Li-ion diffusion coefficient.

327

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

International Nuclear Information System (INIS)

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

328

Study on Thermochromic VO2 Films Grown on ZnO-Coated Glass Substrates for “Smart Windows”  

Science.gov (United States)

Vanadium dioxide (VO2) is one of the most attractive thermochromic materials, which show large changes in optical and electrical properties at the transition temperature (Tt) close to the atmospheric temperature (approximately 340 K). We already reported for VO2 deposition by rf magnetron sputtering using V2O3 or V2O5 targets that VO2 films thicker than 400 nm showed high thermochromic performance, whereas the VO2 films thinner than 200 nm did not show such performance because of their poor crystallinity and off-stoichiometry. In this study, very thin thermochromic VO2 films with thicknesses of about 50 nm were successfully deposited using highly -preferred oriented ZnO polycrystalline films as a buffer layer between the VO2 film and glass substrate (VO2/ZnO/glass) because of the heteroepitaxial growth of VO2 polycrystalline films. W-doped VO2 films were also deposited on the ZnO-coated glass substrates (ZnO/glass) by cosputtering. It was confirmed that W doping for thin VO2 films deposited on the ZnO/glass can decrease Tt systematically. Such very thin VO2 films should have high potential for application in “smart windows”.

Kato, Kazuhiro; Song, Pung Keun; Odaka, Hidehumi; Shigesato, Yuzo

2003-10-01

329

Vanadium oxide bronzes in Na2O - CaO - MO - V2O5 (M = Mg, Ni) systems  

International Nuclear Information System (INIS)

The equilibrium phase diagrams (pO2 = 21 kPa, subsolidus temperatures) of the Na2O - CaO - MgO - V2O5 and Na2O - CaO - NiO - V2O5 four-component systems were constructed in the fields of NaVO3 - Ca(VO3)2 - Mg2V2O7 - V2O5 and NaVO3 - Ca(VO3)2 - Ni3(VO4)2 - V2O5 accordingly. It was shown that formed oxide vanadium bronzes were present in the equilibrium with all (meta-, pyro-, and ortho-) nickel vanadates, with magnesium meta- and pyrovanadates and calcium metavanadate and they were free of Ca2V2O7 and Ca3(VO4)2. Constructed phase diagrams indicating the reactivity of complex oxide systems including oxide V2O5 may be physicochemical reason of some optimum technological parameters used in the vanadium separation from multicomponent raw material

330

Physiochemical studies on the composition and stability of the complexes of VO(II) and UO2(II) with L-lysinemono-hydrochloride  

International Nuclear Information System (INIS)

The VO(II) and UO2(II) form 1:1 and 1:2 complexes with L-lysine monohydrochloride [NH2(CH2)4 CH(NH2) COOH HCl]. Calvin and Melchior's extension of Bjerrum method as modified by Irving and Rossotti have been used for the determination of stability constant at 30 degC and 40 degC at a constant ionic strength (?=0.1M NaClO4). These values were further refined by 'Least Square Method' and 'Schroder's Convergence Formula'. The thermodynamic parameters DELTAG, DELTAH and DELTAS have been also evaluated and their importance in complexation has been discussed. (author)

331

In situ powder X-ray diffraction, synthesis, and magnetic properties of the defect zircon structure ScVO(4-x).  

Science.gov (United States)

We report the formation pathway of ScVO(4) zircon from ScVO(3) bixbyite with emphasis on the synthesis and stability of the novel intermediate defect zircon phase ScVO(4-x) (0.0 ScVO(3) to ScVO(4) involves two intermediates of composition ScVO(3.5+y) (0.00 ScVO(4-x). ScVO(4-x) crystallizes in the defect zircon structure in space group I4(1)/amd (141) with a = 6.77761(5) A and c = 6.14045(8) A. Oxygen defect concentrations in bulk ScVO(4-x) samples range from 0.0 ScVO(4-x) is compared with the fully oxidized zircon structure ScVO(4) using powder X-ray diffraction, neutron diffraction, and bulk magnetic susceptibility data as well as (45)Sc and (51)V solid state NMR spectroscopy. ScVO(4-x) can only be obtained by oxidation of ScVO(3) or ScVO(3.5+y) while the reduction of ScVO(4) does not yield the novel defect structure. Mechanistic insights into the oxidative formation of ScVO(4) via the defect structure are presented. PMID:19894769

Shafi, Shahid P; Kotyk, Matthew W; Cranswick, Lachlan M D; Michaelis, Vladimir K; Kroeker, Scott; Bieringer, Mario

2009-11-16

332

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

Scientific Electronic Library Online (English)

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

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

333

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)

Full Text Available SciELO Argentina | Language: English Abstract in spanish 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.

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

2010-12-01

334

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)

Full Text Available SciELO Argentina | Language: English Abstract in spanish 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.

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

335

Preparation of VO(HPO4)·O.5H2O and its transformation to the maleic anhydride catalyst (VO)2P2O7  

International Nuclear Information System (INIS)

The blue vanadium(IV) compound VO(HPO4)·O.5H2O has been identified as precursor to the maleic anhydride catalyst (VO)2P2O7. Structural similarities between the two compounds suggest a topotactic transformation from hydrogen phosphate to pyrophosphate as the mechanism of catalyst activation. In both compounds, measurement of the magnetic susceptibility as a function of temperature reveals that the major bulk fraction of the vanadium spins are antiferromagnetically coupled, while a variable minor fraction of the defect spins are nearly isolated from the other spins. Two new phases of VOPO4 are formed upon oxidation of VO(HPO4)·O.5H2O. 19 refs.; 5 figs.; 3 tabs

336

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

Scientific Electronic Library Online (English)

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

Rosario, Cisneros; Enrique, Vinatea.

337

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

338

VoIP for Telerehabilitation: A Pilot Usability Study for HIPAA Compliance  

Directory of Open Access Journals (Sweden)

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. 

Briana Ondich

2012-06-01

339

Size-dependent optical and dielectric properties of BiVO4 nanocrystals  

Science.gov (United States)

Optical and dielectric properties of BiVO4 nanocrystals with different particle sizes have been investigated. BiVO4 nanocrystals with different particle sizes were synthesized through a solid-state reaction method followed by mechanical ball milling for different time durations. The samples were characterized by X-ray diffraction, UV-Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy. Direct and indirect band gap energies were found to vary in the range 4.04-4.16 eV and 3.51-3.67 eV respectively, for different particle sizes. The band gap energies are higher with respect to their values in the bulk BiVO4 due to quantum confinement effects. Dielectric properties of the BiVO4 nanocrystals were investigated and it was found that the dielectric constant increased from 32 to 41 for the reduction of particle size from 29 to 7 nm.

Sarkar, S.; Chattopadhyay, K. K.

2012-04-01

340

Infrared characteristics of VO{sub 2} thin films for smart window and laser protection applications  

Energy Technology Data Exchange (ETDEWEB)

Vanadium dioxide (VO{sub 2}) films with a low semiconductor-to-metal transition temperature of 45 Degree-Sign C were fabricated through direct current magnetron sputtering followed by a post-annealing. Atomic force microscopy measurements show that the VO{sub 2} grain size is about one hundred of nanometers. Infrared (IR) characteristic is well investigated by applying a He-Ne laser power intensity measurement, and the result reveals that the VO{sub 2} film exhibits excellent IR switching property. Furthermore, solar smart window and laser protection experiments demonstrate that the obtained VO{sub 2} thin film is a promising material for the application in related fields.

Huang Zhangli; Chen Sihai; Lv Chaohong; Huang Ying; Lai Jianjun [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2012-11-05

 
 
 
 
341

The characteristics of Au:VO2 nanocomposite thin film for photo-electricity applications  

Science.gov (United States)

Au nanoparticles have been fabricated on normal glass substrates using nanosphere lithography (NSL) method. Vanadium dioxide has been deposited on Au/glass by reactive radio frequency (rf) magnetron sputtering. The structure and composition were determined by X-ray diffraction and X-ray photoelectron spectroscope. Electrical and optical properties of bare VO2 and Au:VO2 nanocomposite thin films were measured. Typical hysteresis behavior and sharp phase transition were observed. Nanopartical Au could effectively reduce the transition temperature to 40 °C. The transmittance spectrum for both Au:VO2 nanocomposite thin film shows high transmittance under transition temperature and low transmittance above transition temperature. The characteristics present the Au:VO2 nanocomposite thin film can be used for applications, such as “smart window” or “laser protector”.

Zhu, Yabin; Na, Jie; He, Fan; Zhou, Yueliang

2013-08-01

342

Surface plasmon polaritons in VO2 thin films for tunable low-loss plasmonic applications.  

Science.gov (United States)

We report on the first observation of optically excited surface plasmon polaritons (SPPs) in the conducting phase of vanadium dioxide (VO(2)) thin films. VO(2) is low-loss optical material that undergoes an insulator-metal transition (IMT) under suitable thermal, optical, or electrical stimulation, thus enabling tunable SPP excitation of the conducting phase. Here we applied IR light (1520 nm) to excite SPPs while thermally inducing the IMT by changing the VO(2) temperature, and observed a clear trend from nonabsorption in the insulator phase to high absorption in the conducting phase due to SPP excitation in the latter phase. Tunable SPPs in VO(2) enable a range of opportunities for low-loss optoplasmonic applications since the rate of the IMT excitation can also be tailored. PMID:23073454

Wang, L; Radue, E; Kittiwatanakul, S; Clavero, C; Lu, J; Wolf, S A; Novikova, I; Lukaszew, R A

2012-10-15

343

Association of the eukaryotic V1VO ATPase subunits a with d and d with A.  

Science.gov (United States)

Owing to the complex nature of V(1)V(O) ATPases, identification of neighboring subunits is essential for mechanistic understanding of this enzyme. Here, we describe the links between the V(1) headpiece and the V(O)-domain of the yeast V(1)V(O) ATPase via subunit A and d as well as the V(O) subunits a and d using surface plasmon resonance and fluorescence correlation spectroscopy. Binding constants of about 60 and 200 nM have been determined for the a-d and d-A assembly, respectively. The data are discussed in light of subunit a and d forming a peripheral stalk, connecting the catalytic A(3)B(3) hexamer with V(O). PMID:19289121

Thaker, Youg R; Hunke, Cornelia; Yau, Yin H; Shochat, Susana Geifman; Li, Ying; Grüber, Gerhard

2009-04-01

344

Photocatalytic aerobic oxidation of amines to imines on BiVO4 under visible light irradiation.  

Science.gov (United States)

BiVO4 was found to be an efficient photocatalyst under visible light irradiation for selective oxidation of amines to imines with high activity (99% conversion) and selectivity (up to 99%) using oxygen as an oxidant. PMID:25360458

Yuan, Bo; Chong, Ruifeng; Zhang, Bao; Li, Jun; Liu, Yan; Li, Can

2014-12-21

345

TiVo heitlus elu pärast / John Gartner ; tõlk. Peeter Peetersoo  

Index Scriptorium Estoniae

Peale interaktiivse salvestusseadme TiVo turuletulekut 1997. aastal ei ole ettevõte vaatamate toote headusele suutnud saavutada ootuspäraseid müügitulemusi ega saada suurt kasumit. Artiklis tutvustatakse ettevõtte heitlusi partnerite otsinguil ja edu saavutamisel

Gartner, John

2005-01-01

346

Functional fiber mats with tunable diffuse reflectance composed of electrospun VO2/PVP composite fibers.  

Science.gov (United States)

Thermochromic VO2 nanoparticles have been dispersed into polyvinyl pyrrolidone (PVP) fibers by electrospinning of a VO2-PVP blend solution. The structure and optical properties of the obtained composite fiber mat were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) spectrophotometry, and Fourier transform infrared (FT-IR) spectroscopy. The fiber mat revealed two diffuse reflectance states in infrared spectral region at temperatures under and above the phase transition temperature of VO2 and its IR reflectance is smaller in high temperature. The difference of diffuse reflectance between the two states (?Rdif) was obvious to be more than 25% in the wavelengths from 1.5 ?m to 6 ?m. The diffuse reflectance of the fiber mat could be controlled by adjusting the diameter of the fiber or the content of VO2 in the fibers and this particular optical property was explained by a multiple scattering-absorbing process. PMID:24344924

Li, Shaotang; Li, Yamei; Qian, Kun; Ji, Shidong; Luo, Hongjie; Gao, Yanfeng; Jin, Ping

2014-01-01

347

Diamagnetic to ferromagnetic switching in VO2 epitaxial thin films by nanosecond excimer laser treatment  

Science.gov (United States)

VO2(010)/NiO(111) epitaxial heterostructures were integrated with Si(100) substrates using a cubic yttria-stabilized zirconia (c-YSZ) buffer. The epitaxial alignment across the interfaces was determined to be VO2(010)?NiO(111)?c-YSZ(001)?Si(001) and VO2[100]?NiO?110??c-YSZ?100??Si?100?. The samples were subsequently treated by a single shot of a nanosecond KrF excimer laser. Pristine as-deposited film showed diamagnetic behavior, while laser annealed sample exhibited ferromagnetic behavior. The population of majority charge carriers (e-) and electrical conductivity increased by about two orders of magnitude following laser annealing. These observations are attributed to the introduction of oxygen vacancies into the VO2 thin films and the formation of V3+ defects.

Molaei, R.; Bayati, R.; Nori, S.; Kumar, D.; Prater, J. T.; Narayan, J.

2013-12-01

348

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

DEFF Research Database (Denmark)

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%.

Dencker, Magnus; Hermansen, Bianca

2011-01-01

349

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

Scientific Electronic Library Online (English)

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

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

1999-12-01

350

Biomass and densityofthalassia testudinum beds in mochimabay, Venezuela Biomasa y densidad de praderas de thalassia testudinum en la bahía de mochima, Venezuela  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Un estudio acerca de las variaciones de la biomasa y densidad de Thalassia testudinum fue realizado en cuatro localidades de la Bahía de Mochima, en la costa nororiental de Venezuela. Entre enero y diciembre de 2002, se tomaron ocho réplicas mensuales de sedimento, empleando un perforador de PVC de 15 cm de diámetro, las mismas fueron tamizadas en una malla de 0,5 mm de apertura. El promedio de la temperatura y salinidad fue

Di?az-di?az, Oscar; Lin?ero-arana, Ildefonso

2007-01-01

351

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

Scientific Electronic Library Online (English)

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

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

352

Producción de biomasa y rendimiento de semilla en la asociación girasol (Helianthus annuus L.)-frijol (Phaseolus vulgaris L.) en función del nitrógeno y fósforo  

Digital Repository Infrastructure Vision for European Research (DRIVER)

En 2003 se realizó un estudio en Montecillo, Estado de México, para determinar el efecto de la aplicación de nitrógeno (0, 40 y 80 kg ha?1) y fósforo (0, 30 y 60 kg P2O5 ha?1) en la siembra combinada de girasol (cv. Victoria) y frijol (cv. Michoacán). Con el suministro de 80 kg N ha?1 (80 ? 00 ? 00) se incrementó la producción de biomasa y rendimiento de semilla superando al testigo sin fertilizante en 32% y 35%. Cuando se adicion...

Antonio Lo?pez Sandoval, J.; Alberto Escalante Estrada, J.; Morales Rosales, Edgar J.

2007-01-01

353

Analysis of a procedure for inserting steganographic data into VoIP calls  

CERN Document Server

The paper concerns performance analysis of a steganographic method, dedicated primarily for VoIP, which was recently filed for patenting under the name LACK. The performance of the method depends on the procedure of inserting covert data into the stream of audio packets. After a brief presentation of the LACK method, the paper focuses on analysis of the dependence of the insertion procedure on the probability distribution of VoIP call duration.

Mazurczyk, Wojciech

2008-01-01

354

Evaluation and Investigation of the Delay in VoIP Networks  

Directory of Open Access Journals (Sweden)

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

V. Janata

2011-06-01

355

Electrodynamics of the vanadium oxides VO2 and V2O3  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The optical/infrared properties of films of vanadium dioxide (VO2) and vanadium sesquioxide (V2O3) have been investigated via ellipsometry and near-normal incidence reflectance measurements from far infrared to ultraviolet frequencies. Significant changes occur in the optical conductivity of both VO2 and V2O3 across the metal-insulator transitions at least up to (and possibly beyond) 6 eV. We argue that such changes in optical conductivity and electronic spectral weight over...

Qazilbash, M. M.; Schafgans, A. A.; Burch, K. S.; Yun, S. J.; Chae, B. G.; Kim, B. J.; Kim, H. T.; Basov, D. N.

2008-01-01

356

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Adnan, Muhammad

2012-01-01

357

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

Science.gov (United States)

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

Joushaghani, Arash; Jeong, Junho; Paradis, Suzanne; Alain, David; Stewart Aitchison, J.; Poon, Joyce K. S.

2014-06-01

358

Heat of transport study of the superionic conductor Ag7I4VO4  

International Nuclear Information System (INIS)

The heat of transport of the superionic conductor Ag7I4VO4 has been investigated considering the effect of heat treatment of the material and the thermoelectric power as a function of the temperature. It was found that in the case of highly disordered solids like Ag7I4VO4 the ionic heat of transport tends to be equal to its activation energy

359

Slow component of VO2 kinetics: Mechanistic bases and practical applications  

DEFF Research Database (Denmark)

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.

Jones, Andrew M; Grassi, Bruno

2011-01-01

360

Slow component of VO2 kinetics: mechanistic bases and practical applications.  

Science.gov (United States)

The V·O? slow component, a slowly developing increase in V·O? during constant-work-rate 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·O? slow component and describes practical interventions that can attenuate the slow component and thus enhance exercise tolerance. There is strong evidence that, during constant-work-rate exercise, the development of the V·O? 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·O? slow component) during fatiguing, high-intensity exercise in which additional fiber recruitment is unlikely or impossible. Therefore, it seems that muscle fatigue underpins the V·O? 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·O? slow 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 or by enhancing bulk muscle O2 delivery or local Q·O?-to-V·O? matching. Future honing of these interventions to maximize their impact on the V·O? slow component might improve sports performance in athletes and exercise tolerance in the elderly or in patient populations. PMID:21552162

Jones, Andrew M; Grassi, Bruno; Christensen, Peter M; Krustrup, Peter; Bangsbo, Jens; Poole, David C

2011-11-01

 
 
 
 
361

Infrared absorption spectrum studies of the VO defect in fast-neutron-irradiated Czochralski silicon  

Science.gov (United States)

In this work the difference of annealing behaviors of VO (A-center) in varied doses of neutron-irradiated Czochralski silicon (S1: (5×10 17 n/cm 2) and S2: (1.07×10 19 n/cm 2)) was studied. The vacancy-oxygen complex (VO) is one of the main defects formed in neutron-irradiated Czochralski silicon (CZ-Si). In this defect, the oxygen atom shares a vacancy, it is bonded to two silicon neighbors. Annealed at 200 °C, divacancies are trapped by O i to form the V 2O (840 cm -1). With the decrease in the 829 cm -1 (VO) three infrared absorption bands at 825, 834 and 840 cm -1 (V 2O) rise after being annealed at the temperature range of 200-500 °C. After being annealed at 450-500 °C the main absorption bands in the S1 sample are 834, 825 and 889 cm -1 (VO 2), and 825 and 919.6 cm -1 (O-V-O) in S2. Annealing of the A-center in varied neutron-irradiated CZ-Si consists of two processes. The first is trapping of VO by interstitial oxygen (O i) in low-dose neutron-irradiated CZ-Si (S1) and the second is capturing of the wandering vacancy by VO, etc, in high-dose neutron-irradiated CZ-Si (S2). The VO 2 and O-V-O defects play an important role in the annealing of the A-center. With the increase in the irradiation dose, the annealing behavior of the A-center is changed and the formation of the VO 2 is depressed.

Yang, Shuai; Li, Yangxian; Ma, Qiaoyun; Liu, Lili; Xu, Xuewen; Niu, Pingjuan; Li, Yongzhang; Niu, Shengli; Li, Hongtao

2005-06-01

362

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

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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

Paula Magrani

2010-06-01

363

Sonochemical synthesis, structural, magnetic and grain size dependent electrical properties of NdVO4 nanoparticles.  

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NdVO4 nanoparticles are successfully synthesized by efficient sonochemical method using two different structural directing agents like CTAB and P123. The phase formation and functional group analysis are carried out using X-ray diffraction (XRD) and fourier transform infra red (FT-IR) spectra, respectively. Using Scherrer equation the calculated grain sizes are 27 nm, 24 nm and 20 nm corresponding to NdVO4 synthesized by without surfactant, with CTAB and P123, respectively. The TEM images revealed that the shape of NdVO4 particles is rice-like and rod shaped particles while using CTAB and P123 as surfactants. The growth mechanism of NdVO4 nanoparticles is elucidated with the aid of TEM analysis. From electrical analysis, the conductivity of NdVO4 nanoparticles synthesized without surfactant showed a higher conductivity of 5.5703 × 10(-6) S cm(-1). The conductivity of the material depends on grain size and increased with increase in grain size due to the grain size effect. The magnetic measurements indicated the paramagnetic behavior of NdVO4 nanoparticles. PMID:24090832

Yuvaraj, S; Kalai Selvan, R; Kumar, Vijay Bhooshan; Perelshtein, Ilana; Gedanken, A; Isakkimuthu, S; Arumugam, S

2014-03-01

364

Comparison of Intensities and Rest Periods for VO2max Verification Testing Procedures.  

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We sought to determine the incidence of 'true' VO2max confirmation with the verification procedure across different protocols. 12 active participants (men n=6, women n=6) performed in random order 4 different maximal graded exercises tests (GXT) and verification bout protocols on 4 separate days. Conditions for the rest period and verification bout intensity were: A - 105% intensity, 20?min rest; B - 105% intensity, 60?min rest; C - 115% intensity, 20?min rest; D - 115% intensity, 60?min rest. VO2max confirmation (difference between peak VO2 GXT and verification trialeffect of verification intensity on VO2max confirmation across all exercise test conditions (intensity effect within recovery 20?min (?(2) (1)=4.800, peffect within recovery 60?min (?(2) (1)=6.316, peffect was found for incidence of VO2max confirmation with different rest periods. We recommend the use of 105% of the maximal GXT workload and 20?min rest periods when using verification trials to confirm VO2max in normally active populations. PMID:24886925

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

2014-11-01

365

Impact of thermal expansion of substrates on phase transition temperature of VO2 films  

Science.gov (United States)

Non-epitaxial, (010)M1-oriented VO2 thin films were grown on various substrates [amorphous SiO2, Si (001), Al2O3 (0001), and CaF2 (001)] with Pt (111)/SiO2 buffer layers. Phase transition from MoO2-type monoclinic to rutile-type tetragonal structures of these VO2 layers was investigated with temperature-controlled micro-Raman spectroscopy. It was confirmed that substrates with larger thermal expansion coefficient cause larger out-of-plane lattice spacings of both Pt and VO