233 research outputs found

    FLOOD ROUTING ON RIVERS WITHOUT TRIBUTARIES

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    Promotion of East-West Computer Communication in IIASA's International Environment and the Hungarian Case Study

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    This paper describes the functions of the "IIASA Gateway" as seen by a "typical user", IIASA's Hungarian National Member Organization

    Anomalous codeposition of cobalt and ruthenium from chloride-sulfate baths

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    Codeposition of Ru and Co was studied at room temperature and at 50oC with various Ru3+ and Co2+ concentrations in the electrolyte. The codeposition of Co and Ru proved to be anomalous since no pure Ru could be obtained in the presence of Co2+ in the electrolyte, but a significant Co incorporation into the deposit was detected at potentials where the deposition of pure Co was not possible. The composition of the deposits varied monotonously with the change of the concentration ratio of Co2+ and Ru3+. The deposition of Ru was much hindered and the current efficiency was a few percent only when the molar fraction of Co in the deposit was low. Continuous deposits could be obtained only when the molar fraction of Co in the deposit was at least 40 at.%. The deposit morphology was related to the molar fraction of Co in the deposit. The X-ray diffractograms are in conformity with a hexagonal close-packed alloy and indicate the formation of nanocrystalline deposits. Two-pulse plating did not lead to a multilayer but to a Co-rich alloy. Magnetoresistance of the samples decreased with increasing Ru content

    Enhanced biohydrogen production from beverage industrial wastewater using external nitrogen sources and bioaugmentation with facultative anaerobic strains

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    In this work biohydrogen generation and its improvement possibilities from beverage industrial wastewater were sought. Firstly, mesophilic hydrogen fermentations were conducted in batch vials by applying heat-treated (80°C, 30 min) sludge and liquid (LB-grown) cultures of Escherichia coli XL1-Blue/. Enterobacter cloacae DSM 16657 strains for bioaugmentation purposes. The results showed that there was a remarkable increase in hydrogen production capacities when facultative anaerobes were added in the form of inoculum. Furthermore, experiments were carried out in order to reveal whether the increment occurred either due to the efficient contribution of the facultative anaerobic microorganisms or the culture ingredients (in particular yeast extract and tryptone) supplied when the bacterial suspensions (LB media-based inocula) were mixed with the sludge. The outcome of these tests was that both the applied nitrogen sources and the bacteria (. E. coli) could individually enhance hydrogen formation. Nevertheless, the highest increase took place when they were used together. Finally, the optimal initial wastewater concentration was determined as 5 g/L. © 2014 The Society for Biotechnology, Japan

    Simultaneous biohydrogen production and purification in a double-membrane bioreactor system

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    In this work the establishment of a double-membrane bioreactor was aimed. Initially, a continuous hydrogen fermenter was coupled with a commercial Kubota® microfiltration membrane module and the production performance of the cell-retentive design was evaluated under various hydraulic retention times. As a result, it has been observed that altering HRT influenced the rejection feature of the microfiltration module while had an inverse effect on hydrogen productivity and yield, since shortened HRTs were accompanied by gradually decreasing H2 yields (HY) and progressively increasing volumetric H2 production rates (HPR). The highest HY and HPR were achieved as 1.13 mol H2/mol glucose and 0.24 mol H2/L-d, respectively. Furthermore, a Permselect® (PDMS) gas separation membrane was installed to the anaerobic membrane bioreactor and its ability to separate hydrogen from the raw fermentation gaseous mixture was assessed. The highest purity hydrogen obtained in one-step purification by the PDMS module was 67.3 vol.%, which exceeds 30% enrichment efficiency considering 51.3 vol.% H2 in the feed gas. Hence, it could be concluded that the poly(dimethyl siloxane) membrane has potential to attractively concentrate biohydrogen from fermenter off-gas and may be used for in-situ product recovery

    Review on the start-up experiences of continuous fermentative hydrogen producing bioreactors

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    a b s t r a c t The start-up of continuous biohydrogen fermentations is a complex procedure and a key to acceptable hydrogen production performance and successful long-term operation. In this review article, the experiences gained and lessons learned from relevant literature studies dealing with various aspects of H 2 producing bioreactor start-up are comprehensively surveyed. Firstly, the importance of H 2 -forming biosystem start-up including its main steps is outlined. Afterwards, the role of main influencing factors and methods (e.g. strain selection, seed pretreatment and inocula stimulation, switch-over time, bioreactor design, operating conditions) in avoiding the deterioration of starting a reactor is analyzed and presented in detail. Finally, the so far suggested applicable start-up strategies and the corresponding findings are critically discussed pointing out the advantages and disadvantages of each strategy

    Creep behaviour of injection-moulded basalt fibre reinforced poly(lactic acid) composites

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    In this paper, the creep of short (chopped) basalt fibre reinforced poly(lactic acid) composites was investigated; 5, 10, 20 and 30 wt.% short basalt fibre reinforced composites were prepared by using twin-screw extrusion followed by injection moulding. Differential scanning calorimetry measurements revealed that the basalt fibres had nucleating effect on the poly(lactic acid)grade used in this study, while scanning electron microscopy demonstrated that there was strong adhesion between the fibre and the matrix. Fibre distribution analysis showed that there was no significant statistical difference between the average fibre lengths of all of the produced composites. Finally, creep mastercurves were constructed using the single creep curves obtained by applying 10, 20, 30,…, 90% of the tensile strength of the composites as a static creep loading force. It was demonstrated that the basalt fibres as reinforcements can effectively reduce the strain and increase time to failure of the composites during creep load and thus could open the possibilities for poly(lactic acid)-based composites to be used in long-term constantly loaded structural or engineering applications. </jats:p

    Age group, location or pedagogue: factors affecting parental choice of kindergartens in Hungary

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    Hungary has experienced significant political, economic, demographic and social changes since the end of Soviet domination in the 1990s. The gradual move towards liberal-democracy has been accompanied by growing emphasis on individualism, choice and diversity. Universal kindergarten provision for 5-6 year olds is a long established feature of the Hungarian education system, but little is known about parental choice (Török, 2004). A case study (Yin, 2004) of factors influencing parental choice and satisfaction was undertaken in one Hungarian town. This was based on a survey of 251 parents of children attending both mixed-age and same-age groups across 12 kindergartens. Parents suggested that the most important influences were geographical location and the individual pedagogue(s). Given that traditionally each pedagogue follows ‘their’ cohort from kindergarten entry to primary school, their influence appears heightened. Although generally satisfied with their chosen arrangement, parents from same-age groups expressed significantly more confidence and satisfaction, particularly in relation to cognitive development and preparation for school. Parents appear less convinced about the trend towards mixed-age groups and questions are raised about sufficiency of evidence of their benefits in a Hungarian context and the driving factors behind change
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