On Auxiliary Fields in BF Theories

We discuss the structure of auxiliary fields for non-Abelian BF theories in arbitrary dimensions. By modifying the classical BRST operator, we build the on-shell invariant complete quantum action. Therefore, we introduce the auxiliary fields which close the BRST algebra and lead to the invariant extension of the classical action.Comment: 7 pages, minor changes, typos in equations corrected and acknowledgements adde

Heavy metals concentration in soils from parks and green areas in Belgrade

The current study included the investigation of several metals and their distribution in urban soils from parks and green areas in the city of Belgrade. The soils were sampled in January and February 2008. The concentrations of Cd, Co, Cu, Pb, Mn and Zn were measured, as well as the pH values and organic matter contents. The obtained results showed that there was a significant level of contamination in some samples, especially with lead, and that it was most probably caused by anthropogenic activities, mostly from traffic. The results were compared with the National legislation and Netherlands standards. Also, the recent results were compared with the data from previous work and it was concluded that there has been a certain increase of the Pb concentration in the past three years. The level of pollution in playground soil was very high and each analyzed sample exceeded the Dutch target value for Cd, Co and Pb

Neanderthals on the Lower Danube: Middle Palaeolithic evidence in the Danube Gorges of the Balkans

The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River – Tabula Traiana and Dubočka-Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state-of-the-art analytical procedures. The presentation focuses on micromorphological analyses of the caves’ sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term

Neanderthals on the Lower Danube: Middle Palaeolithic evidence in the Danube Gorges of the Balkans

The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River – Tabula Traiana and Dubočka-Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state-of-the-art analytical procedures. The presentation focuses on micromorphological analyses of the caves’ sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term

Influence of Technological Parameters on the Combustion Velocity of Pyrotechnic Compositions for Gas Generator of Base Bleed Projectiles

The specific purpose of a pyrotechnic mixture for a Gas Generator (GG) of Base Bleed (BB) projectile requires a carefully balanced combustion velocity for obtaining the maximum projectile range and avoiding a reactive propelling force. The development of the pyrotechnic element is done under laboratory conditions which often differ from the real usage conditions. To be able to fairly predict the combustion process characteristics in the real GGs of BB projectiles, some influential technological factors and their influence on the combustion velocity have been investigated. Factors which were observed to have the most significant influence on the combustion velocity of pyrotechnic compositions are charge density, oxygen balance, combustion chamber wall thickness and material type. Individual and combined influence of these factors on the combustion velocity will also be presented in this paper

Electrocatalytic properties of surface oxides on gold, platinum, and stainless steel electrodes in electrooxidation of malic acid

Electrocatalytic properties of oxides formed at gold, platinum, and stainless steel electrodes in the malic acid electrooxidation in 0.1 M Na 2 SO 4 are studied. Gas chromatographic analysis of the electrolyte after holding the potential at 1.0 V for 8 h shows that on platinum and gold electrodes 2 mmol of acetaldehyde are produced and on stainless steel, 45 mmol. The acetaldehyde yield is the highest on stainless steel

Influence of Copper Wire Heat Guides on the Combustion Velocity of Organic Based Charges for Gas Generators of Base Bleed Projectiles

Organic fuel based pyrotechnic charges for gas generators (GG) of Base Bleed (BB) projectiles have shown better combustion characteristics than metallic based ones. Since organic fuel based compositions are representative of energy poor pyrotechnic mixtures, they combust at lower combustion velocities. Conventional methods for heat transfer enhancement of GG charges, based on the introduction of metallic fuel components into pyrotechnic mixtures, are very successful in raising the combustion velocity, but inevitably, they also tend to force production of solid and liquid combustion products which reduce the GG charge’s functionality. In this paper, the results obtained by inserting copper wires (copper wire heat guides (HG)) into organic-based gas generator charges will be presented. The aim of inserting copper wires was to enhance the combustion velocity by influencing on the thermal heat transfer of GG charges. The results have shown that copper wire heat guides had a positive influence on the GG charges heat transfer, resulting in a 15-20% rise in the combustion velocity, without any of the side effects observed in the case of the addition of metallic fuels to GG charges

Kinetic Study of Sr2+Sorption by Bone Char

The effect of particle size, bone char mass, initial pH, and metal concentration on the kinetics of Sr2+ sorption by bone char was studied and discussed. Considering the sorbed amounts of Sr2+, solution pH changes, changes of Ca2+ concentrations and Ca/Sr molar ratios, with time, it was concluded that surface complexation reactions are dominant in the first, more rapid stage of the sorption process, while the contribution of the ion-exchange mechanism increases with time and becomes more significant in the second, slower phase. Under all investigated experimental conditions, the pseudo-second-order model was found to provide high correlation coefficients and the equilibrium amounts of Sr2+ sorbed comparable to the values obtained experimentally

Comparative study of differently treated animal bones for Co2+ removal

The objective of the present study was the evaluation of differently treated bovine bones for Co2+ removal from aqueous media. Powdered bones (B), as well as samples prepared by H2O2 oxidation (BH2O2) and annealing at 400-1000 degrees C (B400-B1000), were tested as sorbent materials. A combination of XRD, FTIR spectroscopies, DTA/TGA analyses, specific surface area (S-p) and point of zero charge (pH(PZC)) measurements was utilized for physicochemical characterization of sorbents. Sorption of Co2+ was studied in batch conditions as a function of pH, contact time and Co2+ concentration. Initial pH values in the range4-8 were found optimal for sorption experiments. Equilibrium time of 24 h was required in all investigated systems. The maximum sorption capacities differ significantly from 0.078 to 0.495 mmol/g, whereas the affinity towards Co2+ decreased in the order: B400 GT BH2O2 GT B600 GT B GT B800 GT B1000. The pseudo-second-order model and Langmuir theoretical equation were used for fitting the kinetic and equilibrium data, respectively. Ion-exchange with Ca2+ and specific cation sorption were identified as main removal mechanisms. The amounts of Co2+ desorbed from loaded bone sorbents increased with the decrease of pH as well as with the increase of Ca2+ concentration. Heating at 400 degrees C was found to be an optimal treatment for the production of the Co2+ removal agent. (C) 2008 Elsevier B.V. All rights reserved

A treatment of wastewater containing basic dyes by the use of new strain Streptomyces microflavus CKS6

This study has investigated the biodegradable potential of the Streptomyces microflavus CKS6 growing microbial cells for the colored waste water treatment. The Crystal violet and Safranin T basic dyes have been employed as a model compounds for decolorization evaluation by exploring the correlation with the other rate-dependent environmental parameters. Through the measuring of color reduction by UV Vis spectroscopic monitoring analysis, the results revealed well operational properties of Streptomyces microflavus CKS6 for the successful refinement of dyes contaminate water solutions. Optimized process parameters were found to be apparently mild, involving the use of the reaction temperature of 27-30 degrees C and pH 6-7. With the lower dye concentrations, the decolorization efficiency was found to be more effective and rapid, wherein the 1 mg/L of Crystal violet was removed within the 2.5 h of the treatment time, while the solution with the same content of the Safranin T dye required 30 h. A possible mechanism for the working medium decolorization was accomplished in two consecutive steps, by the primarily dye adsorption onto the bacterial cells surface, followed to biodegradation by the active microbial enzymatic system, wherein the lignin peroxidase acts a notable role. The phytotoxicity analysis of the degradation products revealed less toxicity to the plants, compared to parental chemicals. In addition, the adaptation of individual dye optimized parameters was effectively implemented in the real waste water system containing the mixture of these two dyes. The overall results may postulate that Streptomyces microflavus CKS6 may be promising applicants for dye contaminated Water treatment