62,627 research outputs found

    Microbial Effects on Repository Performance

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    This report presents a critical review of the international literature on microbial effects in and around a deep geological repository for higher activity wastes. It is aimed at those who are familiar with the nuclear industry and radioactive waste disposal, but who are not experts in microbiology; they may have a limited knowledge of how microbiology may be integrated into and impact upon radioactive waste disposal safety cases and associated performance assessments (PA)

    The climate change challenge and transitions for radical changes in the European steel industry

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    Cet article vise à identifier les transitions technologiques en cours dans la sidérurgie européenne. Les limites actuelles du système socio-technique centré autour du haut-fourneau, impliquent en effet des changements dans les modes production, de distribution et de consommation d'acier. L'agenda évolue de la recherche de process plus propre (« cleaner production ») vers des innovations de système. Les technologies radicales ULCOS (Ultra Low CO2 Steelmaking) doivent répondre à la modification de l'environnement de sélection mais leur adoption et diffusion dépendra fortement du niveau de la contrainte « carbone » et des fondamentaux identifiés par l'économie industrielle et l'approche évolutionniste.Les experts du secteur ont aussi identifié le besoin d'un agenda de recherche dédié aux modes de consommation de matériaux à long terme. L'évolution du contenu en matériaux et énergie des infrastructures, produits et services (mobilité, logement, chauffage, éclairage...) est fortement susceptible d'évoluer, en particulier dans le cadre de contraintes « carbone » fortes. L'approche « PSS » ou « product-service-system » dans le transport et la construction peut devenir une opportunité pour la sidérurgie du 21eme siècle.changement climatique;eco-efficacité;industrie sidérurgique;innovation

    Investigation into high-temperature corrosion in a large-scale municipal waste-to-energy plant

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    High-temperature corrosion in the superheater of a large-scale waste-to-energy plant was investigated. A comparison of nickel-/iron-based alloys and austenitic stainless steel probes placed in the furnace demonstrated that temperature and particle deposition greatly influence corrosion. Nickel-based alloys performed better than the other metal alloys, though an aluminide coating further increased their corrosion resistance. Sacrificial baffles provided additional room for deposit accumulation, resulting in vigorous deposit-induced corrosion. Computational modelling (FLUENT code) was used to simulate flow characteristics and heat transfer. This study has shown that the use of aluminide coatings is a promising technique for minimising superheater corrosion in such facilities. (C) 2010 Elsevier Ltd. All rights reserved

    RRS Discovery Cruise DY017, 20 Oct - 05 Nov 2014. Outer Hebrides process cruise

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    The continental shelf region immediately west of the UK and North of Ireland is thought to be a key region for the exchange of nutrients, carbon and water between the NW European continental shelf and the open North Atlantic Ocean yet it remains comparatively under sampled. Within the context of the NERC/DEFRA co-funded Shelf Sea Biogeochemistry programme, which aims to improve our understanding of the role of shelf seas in the global carbon cycle, this cruise undertook a regional scale survey to determine the distribution and concentrations of dissolved inorganic carbon, inorganic nutrients, trace metals, and other ancillary data on the Malin and Hebridean Shelves. Of the seven planned transects, six were completed with the seventh abandoned due to poor weather but a rich dataset of key biogeochemical parameters has been collected which will enable work on the stoichiometry of dissolved nutrients and exchange with the open ocean to be undertaken

    Effect of flow pattern at pipe bends on corrosion behaviour of low carbon steek and its challenges

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    Recent design work regarding seawater flow lines has emphasized the need to identify, develop, and verify critical relationships between corrosion prediction and flow regime mechanisms at pipe bend. In practice this often reduces to an pragmatic interpretation of the effects of corrosion mechanisms at pipe bends. Most importantly the identification of positions or sites, within the internal surface contact areas where the maximum corrosion stimulus may be expected to occur, thereby allowing better understanding, mitigation, monitoring and corrosion control over the life cycle. Some case histories have been reviewed in this context, and the interaction between corrosion mechanisms and flow patterns closely determined, and in some cases correlated. Since the actual relationships are complex, it was determined that a risk based decision making process using selected ‘what’ if corrosion analyses linked to ‘what if’ flow assurance analyses was the best way forward. Using this in methodology, and pertinent field data exchange, it is postulated that significant improvements in corrosion prediction can be made. This paper outlines the approach used and shows how related corrosion modelling software data such as that available from corrosion models Norsok M5006, and Cassandra to parallel computational flow modelling in a targeted manner can generate very noteworthy results, and considerably more viable trends for corrosion control guidance. It is postulated that the normally associated lack of agreement between corrosion modelling and field experience, is more likely due to inadequate consideration of corrosion stimulating flow regime data, rather than limitations of the corrosion modelling. Applications of flow visualization studies as well as computations with the k-ε model of turbulence have identified flow features and regions where metal loss is a maximu

    Long-term evolution of highly alkaline steel slag drainage waters

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    © 2015, Springer International Publishing Switzerland. The disposal of slag generated by the steel industry can have negative consequences upon the surrounding aquatic environment by the generation of high pH waters, leaching of potentially problematic trace metals, and rapid rates of calcite precipitation which smother benthic habitats. A 36-year dataset was collated from the long-term ambient monitoring of physicochemical parameters and elemental concentrations of samples from two steel slag leachate-affected watercourses in northern England. Waters were typified by elevated pH ( > 10), high alkalinity, and were rich in dissolved metals (e.g. calcium (Ca), aluminium (Al), and zinc (Zn)). Long-term trend analysis was performed upon pH, alkalinity, and Ca concentration which, in addition to Ca flux calculations, were used to highlight the longevity of pollution arising as a result of the dumping and subsequent leaching of steel slags. Declines in calcium and alkalinity have been modest over the monitoring period and not accompanied by significant declines in water pH. If the monotonic trends of decline in alkalinity and calcium continue in the largest of the receiving streams, it will be in the region of 50–80 years before calcite precipitation would be expected to be close to baseline levels, where ecological impacts would be negligible

    Fluorescence characterization of clinically-important bacteria

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    Healthcare-associated infections (HCAI/HAI) represent a substantial threat to patient health during hospitalization and incur billions of dollars additional cost for subsequent treatment. One promising method for the detection of bacterial contamination in a clinical setting before an HAI outbreak occurs is to exploit native fluorescence of cellular molecules for a hand-held, rapid-sweep surveillance instrument. Previous studies have shown fluorescence-based detection to be sensitive and effective for food-borne and environmental microorganisms, and even to be able to distinguish between cell types, but this powerful technique has not yet been deployed on the macroscale for the primary surveillance of contamination in healthcare facilities to prevent HAI. Here we report experimental data for the specification and design of such a fluorescence-based detection instrument. We have characterized the complete fluorescence response of eleven clinically-relevant bacteria by generating excitation-emission matrices (EEMs) over broad wavelength ranges. Furthermore, a number of surfaces and items of equipment commonly present on a ward, and potentially responsible for pathogen transfer, have been analyzed for potential issues of background fluorescence masking the signal from contaminant bacteria. These include bedside handrails, nurse call button, blood pressure cuff and ward computer keyboard, as well as disinfectant cleaning products and microfiber cloth. All examined bacterial strains exhibited a distinctive double-peak fluorescence feature associated with tryptophan with no other cellular fluorophore detected. Thus, this fluorescence survey found that an emission peak of 340nm, from an excitation source at 280nm, was the cellular fluorescence signal to target for detection of bacterial contamination. The majority of materials analysed offer a spectral window through which bacterial contamination could indeed be detected. A few instances were found of potential problems of background fluorescence masking that of bacteria, but in the case of the microfiber cleaning cloth, imaging techniques could morphologically distinguish between stray strands and bacterial contamination

    Geography and intra-national home bias : U.S. domestic trade in 1949 and 2007

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    This paper examines home bias in U.S. domestic trade in 1949 and 2007. We use a unique data set of 1949 carload waybill statistics produced by the Interstate Commerce Commission, and 2007 Commodity Flow Survey data. The results show that home bias was considerably smaller in 1949 than in 2007 and that home bias in 1949 was even negative for several commodities. We argue that the difference between the geographical distribution of the manufacturing activities in 1949 and that of 2007 is an important factor explaining the differences in the magnitudes of home-bias estimates in those years
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