Intermetallics – advanced cathode materials in the electrolytic production of hydrogen

The intermetallics, Ti–Pt, Nb-Pd (80%Nb), Pd-Ta, Nb-Pd (65% Nb), Zr-Pt, Hf2Fe and PtMo3, of transition metals have been investigated as cathode materials for the electrolytic hydrogen evolution in an attempt to increase the electrolytic process efficiency. These materials were compared with conventional cathode, Ni. An significant upgrade of the electrolytic efficiency using intermetallics was achived. The effects of those cathode materials on the process efficiency were discussed in the context of transition metal features that issue from their d-electronic configuration.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Energy consumption in the electrolytic evolution of hydrogen with iron-nickel electrodes

The possibilities to reduce energy consumption in the electrolytic hydrogen production using ionic activators added into an alkaline electrolyte have been investigated. Two cathode/anode systems, Fe/Ni and Ni/Fe were investigated. We have found that some activators, like tris-(ethylenediamine)Co(III) chloride complex in combination with the sodium molybdate can reduce energy needs per mass unit of hydrogen produced for more than ten percent in all investigated systems compared to those of non-activated electrolytes. Additionally, iron exhibits some special properties in this view.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Morphological characterization of sweet sorghum genotypes across environments

Sweet sorghum being a C4 crop accumulates more sugar in its stalks, also suitable for biofuel production and has high degree of tolerance to biotic and abiotic stresses. Morphological characteristics i.e., plant height, plant biomass, leaves on the stem, panicle length and yield of crude biomass of sweet sorghum genotypes were studied across different environments. Environments and genotype by environment interaction (GEI) had a significant effect on the yield of crude biomass. The smallest yield of crude biomass was achieved in 2016 (42.54 t ha(-1)), which was found significantly lower as compared to that in 2014 and 2015. The average plant height had a significant and positive correlation with the number of leaves (0.54) and number of leaves had highly a significant and positive correlation with the mass of stem (0.46) and panicle length (0.61). Biomass yield was positively and significantly correlated with precipitation (0.72) and negatively significantly correlated with temperature (-0.57). In breeding of sweet sorghum, the highest attention should be given to biomass yield as it manage the whole variation and controlled by polygenes

The influence of boron addition on properties of copper-zirconium alloys

Copper-zirconium alloys with high conductivity were produced using powder metallurgy. Two-steps manufacturing process, containing mechanical alloying followed by hot pressing, was applied in achieving improved mechanical and physical properties of Cu-Zr alloy. In this paper, the influence of boron on Cu-Zr alloys properties was studied on Cu-1Zr (wt.%) and Cu-1.1Zr-0.3B (wt.%) systems. Scanning electron microscopy, laser nanoparticle sizer, computed tomography and X-ray diffraction were employed for observation of changes in the microstructure during production steps. More specifically – variations in size of the Cu particles, powder mixtures’ structural parameters, and development of CuZr phase in binary alloy, CuZr phase and ZrB2 particles in ternary alloy were observed. It was shown that presence of boron increases dislocation density in ternary alloy over the mechanical alloying time compared to binary alloy. The results presented in this study show higher hardening effect in Cu-Zr-B alloy compared to Cu-Zr alloy, resulting in stable hardness values during thermomechanical treatment. Further, it can be seen that finely dispersed reinforcing ZrB2 particles in copper matrix does not have significant influence on its conductivity. Moreover, both systems Cu-Zr and Cu-Zr-B exhibit better electrical conductivity after thermomechanical treatment as a result of zirconium reduction in solid solution due to its precipitation.Високо проводне легуре бакра са додатком цирконијума произведене су металургијом праха. У постизању побољшаних механичких и физичких својстава CuZr легуре примењен је двостепени процес производње, који садржи механичко легирање праћено топлим пресовањем. У овом раду проучаван је утицај бора на својства Cu-Zr легура поређењем система Cu-1Zr (теж.%) и Cu-1.1Zr-0.3В (теж.%). Промене у микроструктури током производних корака праћене су помоћу метода: скенирајућа електронска микроскопија, ласерско одређивање величина микро- и наночестица, компјутерска томографија и рендгенска дифракција. Посебно су посматране варијације у величини честица бакра, структурних параметара мешавине праха и развој CuZr фазе у бинарној легури, као и CuZr фазе и ZrВ2 честица у терцијарној легури. Показало се да присуство бора повећава густину дислокација у терцијарној легури током механичког легирања у поређењу са бинарном легуром. Резултати приказани у овој студији показују већи ефекат ојачавања у легури Cu-Zr-B у поређењу са легуром Cu-Zr, што резултира стабилним вредностима тврдоће током термичке обраде. Даље, може се видети да фино дисперговане честице ZrB2 у матрици бакра показују незнатан утицај на њену проводљивост. Такође, оба система Cu-Zr и Cu-Zr-B показују бољу електричну проводљивост након термичке обраде као резултат редукције цирконијума у чврстом раствору услед његовог таложења

Improving emerging European NMIs’ capabilities in humidity measurement

The control and measurement of humidity is important for many industrial applications and to ensure the appropriate storage of materials and products. Humidity measurement techniques are diverse and each presents different challenges for use and calibration for a range of pressures and gases. Over the past few years, the development of humidity sensors and apparatus has matured to a level where traceable calibration is beneficial to all industries in which humidity and moisture measurement and control are important. This paper deals with a European project in which the overall objective is to develop or extend the measurement and research capabilities of the participating emerging NMI/DIs’ countries in the field of humidity measurements, where access to these types of facilities is currently limited

"It All Ended in an Unsporting Way": Serbian Football and the Disintegration of Yugoslavia, 1989-2006

Part of a wider examination into football during the collapse of Eastern European Communism between 1989 and 1991, this article studies the interplay between Serbian football and politics during the period of Yugoslavia's demise. Research utilizing interviews with individuals directly involved in the Serbian game, in conjunction with contemporary Yugoslav media sources, indicates that football played an important proactive role in the revival of Serbian nationalism. At the same time the Yugoslav conflict, twinned with a complex transition to a market economy, had disastrous consequences for football throughout the territories of the former Yugoslavia. In the years following the hostilities the Serbian game has suffered decline, major financial hardship and continuing terrace violence, resulting in widespread nostalgia for the pre-conflict era

Cascades with Adjoint Matter: Adjoint Transitions

A large class of duality cascades based on quivers arising from non-isolated singularities enjoy adjoint transitions - a phenomenon which occurs when the gauge coupling of a node possessing adjoint matter is driven to strong coupling in a manner resulting in a reduction of rank in the non-Abelian part of the gauge group and a subsequent flow to weaker coupling. We describe adjoint transitions in a simple family of cascades based on a Z2-orbifold of the conifold using field theory. We show that they are dual to Higgsing and produce varying numbers of U(1) factors, moduli, and monopoles in a manner which we calculate. This realizes a large family of cascades which proceed through Seiberg duality and Higgsing. We briefly describe the supergravity limit of our analysis, as well as a prescription for treating more general theories. A special role is played by N=2 SQCD. Our results suggest that additional light fields are typically generated when UV completing certain constructions of spontaneous supersymmetry breaking into cascades, potentially leading to instabilities.Comment: 29 pages, a few typos fixed, improved discussion, added figure; now there is 1 figur

Effects of momentum conservation on the analysis of anisotropic flow

We present a general method for taking into account correlations due to momentum conservation in the analysis of anisotropic flow, either by using the two-particle correlation method or the standard flow vector method. In the latter, the correlation between the particle and the flow vector is either corrected through a redefinition (shift) of the flow vector, or subtracted explicitly from the observed flow coefficient. In addition, momentum conservation contributes to the reaction plane resolution. Momentum conservation mostly affects the first harmonic in azimuthal distributions, i.e., directed flow. It also modifies higher harmonics, for instance elliptic flow, when they are measured with respect to a first harmonic event plane such as one determined with the standard transverse momentum method. Our method is illustrated by application to NA49 data on pion directed flow.Comment: RevTeX 4, 10 pages, 1 eps figure. Version accepted for publication in Phys Rev

Antimicrobial and antioxidant properties of methanol extract, fractions and compounds from the stem bark of Entada abyssinica Stend ex A. Satabie

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to evaluate the antimicrobial and antioxidant activities of the methanol extract, fractions and isolated compounds from <it>Entada abyssinica </it>stem bark, plant used traditionally against gastrointestinal infections.</p> <p>Methods</p> <p>The methanol extract of <it>E. abyssinica </it>stem bark was pre-dissolved in a mixture of methanol and water, and then partitioned between <it>n</it>-hexane, ethyl acetate and <it>n</it>-butanol. The ethyl acetate portion was fractionated by column chromatography and the structures of isolated compounds elucidated by analysis of spectroscopic data and comparison with literature data. Antimicrobial activity was assayed by broth microdilution techniques on bacteria and yeasts. The antioxidant activity was determined by DPPH radical scavenging method.</p> <p>Results</p> <p>Four known compounds [(5<it>S</it>,6<it>R</it>,8a<it>R</it>)-5-(carboxymethyl)-3,4,4a,5,6,7,8,8a-octahydro-5,6,8a-trimethylnaphthalenecarboxylic acid (<b>1</b>), methyl 3,4,5-trihydroxybenzoate (<b>2</b>), benzene-1,2,3-triol (<b>3</b>) and 2,3-dihydroxypropyltriacontanoate (<b>4</b>)] were isolated. Compared to the methanol extract, fractionation increased the antibacterial activities of the <it>n</it>-hexane and ethyl acetate fractions, while the antifungal activities increased in ethyl acetate, <it>n</it>-butanol and aqueous residue fractions. The isolated compounds were generally more active on bacteria (9.7 to 156.2 μg/ml) than yeasts (78.1 to 312.5 μg/ml). Apart from compound <b>1</b>, the three others displayed DPPH^·scavenging activity (RSa), with RSa₅₀values of 1.45 and 1.60 μg/ml.</p> <p>Conclusion</p> <p>The results obtained from this study support the ethnomedicinal use of <it>E. abyssinica </it>in the treatment of gastrointestinal infections and the isolated compounds could be useful in the standardisation of antimicrobial phytomedicine from this plant.</p