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Many Industrial (many + industrial)

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Chemistry75%

Terms modified by Many Industrial

  • many industrial application
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    Selected Abstracts

    Inhibition of sulfide on the simultaneous removal of nitrate and p -cresol by a denitrifying sludge

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2008
    Edna R Meza-Escalante
    Abstract BACKGROUND: Many industrial discharges, such as those generated from petrochemical refineries, contain large amounts of sulfurous, nitrogenous and organic contaminants. Denitrification has emerged as a suitable technology for the simultaneous removal of these pollutants in a single reactor unit; however, more evidence is demanded to clarify the limitations of denitrification on the simultaneous removal of sulfide and phenolic contaminants and to optimize the biological process. The aim of this study was to evaluate the capacity of a denitrifying sludge to simultaneously convert sulfide and p -cresol via denitrification. RESULTS: Sulfide was the preferred electron donor over p -cresol, imposing a 5 h lag phase (required for complete sulfide removal) on organotrophic denitrification. Addition of sulfide (20 mg S2, L,1) to p -cresol-amended denitrifying cultures also decreased the reduction rate of nitrate and nitrite, as well as the production rate of nitrogen gas. Nitrite reduction rate was the most affected step by sulfide, decreasing from 35 to 21 mg N (g VSS d),1. A synergistic inhibitory effect of nitrate and sulfide was also observed on nitrite reduction. Despite the effects of sulfide on the respiratory rates monitored, complete removal of nitrate, sulfide and p -cresol could be achieved after 48 h of incubation. CONCLUSION: Our results suggest that simultaneous removal of sulfide and p -cresol could be achieved in denitrifying reactors, but a large hydraulic residence time may be required to sustain an efficient process due to inhibitory effects of sulfide. Copyright © 2008 Society of Chemical Industry [source]

    Thermal Blending Time Associated With a Charge of Hot Particles Added to a Fluidized Bed of Uniform Temperature

    THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2006
    W. A. Brown
    Abstract The process of heat transfer between particles in a fluidized bed is important for many industrial fluidized bed processes. The problem associated with studying this phenomenon is the confounding effect of particle mixing on heat transfer. The work described here was undertaken to describe the process in which heat is added to a fluid bed process by adding a hot charge of particles to a colder fluidized bed. The rate of heat transfer in this instance can have a significant impact on performance of the fluid bed process, depending upon its application. Both the method of analysis and the results of the work are applicable to other fluidized bed processes, particularly those associated with the thermal upgrading of heavy oil. The method of data analysis, based on binomial statistics, allowed useful data to be extracted from a complex system without the need for a large number of experiments. The analysis also allowed for some assessment of the relative importance of mixing and heat transfer, which has not been possible with other approaches. The results of the experiments were further explored using a bubbling bed model that incorporated both heat transfer and solids mixing. This allowed for the formation of a conceptual model, validated by the experimentation, that explains the relative functions of the two transfer processes in the dispersion of heat from a hot charge of particles to the bulk of a fluidized bed. Le procédé de transfert de chaleur entre les particules dans un lit fluidisé joue un rôle important dans de nombreux procédés industriels en lit fluidisé. Le problème associé à l'étude de ce phénomène est l'effet de confusion du mélange des particules sur le transfert de chaleur. Le travail décrit ici a été entrepris pour décrire le procédé dans lequel un lit fluidisé est chauffé en ajoutant une charge chaude de particules à lit fluidisé plus froid. Le taux de transfert de chaleur dans cet exemple peut avoir un impact significatif sur la performance du procédé en lit fluidisé, selon son application. Autant la méthode d'analyse que les résultats du travail sont applicables à d'autres procédés de lits fluidisés, en particulier ceux associés à la valorisation thermique de l'huile lourde. La méthode d'analyse des données, basée sur des statistiques binomiales, permet d'extraire des résultats utiles d'un système complexe sans avoir besoin de beaucoup d'expériences. L'analyse permet également de jauger l'importance relative du mélange et du transfert de chaleur, ce qui n'a pas été possible avec d'autres approches. Les résultats des expériences ont été analysés de manière plus approfondie au moyen d'un modèle à lit bouillonnant qui incorpore à la fois le transfert de chaleur et le mélange de solides. Ceci permet l'établissement d'un modèle conceptuel validé, qui explique les fonctions relatives des deux procédés de transfert dans la dispersion de la chaleur à partir d'une charge chaude de particules dans le coeur d'un lit fluidisé. [source]

    CAN TUNISIA MOVE TO INFLATION TARGETING?

    THE DEVELOPING ECONOMIES, Issue 1 2007
    Adel BOUGHRARA
    E47; E52; E58 Inflation targeting has become an alternative monetary strategy that has been followed by many industrial and emerging countries. This study considers whether the adoption of inflation targeting would be relevant for Tunisia. More specifically, this paper aims at checking whether the necessary conditions for the successful implementation of such a strategy are fulfilled or not. It is found that fiscal dominance does not constitute the main hindrance to the adoption of inflation targeting. Other impediments have been identified, especially a weak financial system in general, the unsound and fragile banking system in particular, and the glaring lack of knowledge about the monetary transmission mechanism. Furthermore, it has been pointed out that if Tunisian monetary authorities continue to carry out the present exchange rate regime, namely, the constant real exchange rate rule, an inflation targeting regime will not be sufficient to properly contain the inflation pressures caused by demand shocks. [source]

    Overexpression, crystallization and preliminary X-ray crystallographic analysis of d -ribose-5-phosphate isomerase from Clostridium thermocellum

    ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2009
    Junho Jung
    Rare sugars are used for many industrial and medical purposes and are produced by the interconversion between aldoses and ketoses catalyzed by sugar and sugar-phosphate isomerases. Recently, Clostridium thermocellumd -ribose-5-phosphate isomerase (CTRPI), an aldose,ketose isomerase, was cloned in order to synthesize d -allose and its substrate specificity was further characterized for industrial usage. CTRPI has a novel substrate specificity that differs from those of other isomerases, which have broad substrate specificities. CTRPI prefers aldose substrates such as l -talose, d -ribose and d -allose. CTRPI was purified and crystallized in order to determine its three-dimensional structure and thus to elucidate its enzymatic reaction mechanism and understand its substrate specificity. The crystal belonged to the trigonal space group P3221, with unit-cell parameters a = b = 69.5, c = 154.4,Å, and diffracted to 1.9,Å resolution. According to Matthews coefficient calculations, the crystallographic structure consists of a dimer in the asymmetric unit, with a VM of 3.2,Å3,Da,1 and a solvent content of 61.7%. [source]