The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Roberto Nigro - One of the best experts on this subject based on the ideXlab platform.
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Surface-to-bed heat transfer in fluidised beds of fine particles
Powder Technology, 2009Co-Authors: Francesco Di Natale, Amedeo Lancia, Roberto NigroAbstract:Abstract This work reports experimental results on the heat transfer between a fluidised bed of fine particles and a Submerged Surface. Experiments have been carried out using different bed materials (polymers, ballotini, corundum, carborundum and quartz sand) with Archimedes number between 2 and 50. Dry air at ambient pressure and temperature has been used as fluidising gas. Three different exchange Surfaces, namely a sphere and two cylinders with different base diameter and same height, have been used. Experimental results show that the heat transfer coefficient increases with particle Archimedes number and is almost independent from particle thermal conductivity for K p / K g > 30. Finally, the comparison of heat transfer coefficient for the different Surfaces shows that the effect of the Surface geometry may account for a 30% variation in the heat transfer coefficient, with higher differences occurring for coarser particles.
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A single particle model for Surface-to-bed heat transfer in fluidized beds
Powder Technology, 2008Co-Authors: Francesco Di Natale, Amedeo Lancia, Roberto NigroAbstract:This paper presents a semi empirical single particle model for the description of heat transfer coefficient between a Submerged Surface and a fluidized bed. The model is applied to several experimental data and gives a satisfactory description of the effect of pressure, temperature and bed material properties on the heat transfer coefficient either in bubbling or slugging fluidized beds. The model considers the averaged Surface void fraction as the only regression parameter for the description of experimental data. Surface void fraction results to be a function of Archimedes number and minimum fluidization bed voidage and its value is consistent with the numerical and experimental data reported in literature.
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Surface-to-bed heat transfer in fluidised beds: Effect of Surface shape
Powder Technology, 2007Co-Authors: Francesco Di Natale, Amedeo Lancia, Roberto NigroAbstract:In recent times, the possible application of fluidisation technologies to the Surface treatments of engineering materials becomes a subject of growing interest both for manufacturing and chemical industries. Heat and mass transfer rates between the Surface and the fluidised bed strongly influence the performance of the Surface treatment. Experimental results of heat transfer between a Submerged Surface and a fluidised bed are presented in this article. This work is focused on the influence of bed material properties and Surface geometry on heat transfer coefficient. Experimental tests show that the heat transfer coefficient is notably affected by the shape of the immersed Surface resulting higher for Surfaces with better aerodynamic shape. An interpretative model, based on the dimensional analysis, has been used for the description of the experimental results.
Gregory M. Ruiz - One of the best experts on this subject based on the ideXlab platform.
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the role of containerships as transfer mechanisms of marine biofouling species
Biofouling, 2009Co-Authors: Ian C. Davidson, Christopher W. Brown, Mark D. Sytsma, Gregory M. RuizAbstract:Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their Submerged Surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large Surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had Submerged Surface areas of >7000 m(2), and fouling coverage on this area was estimated to be <17 m(2) per vessel, with zero biota detected on the hulls of many vessels. The outlying smaller vessel (4465 m(2)) had an estimated coverage of 90% on the hull and also differed substantially from the other ships in terms of its recent voyage history, shorter voyage range and slower speeds. Despite the low extent of fouling, taxonomic richness was high among vessels. Consistent with recent studies, a wide range of organisms were concentrated at more protected and heterogeneous (non-hull) niche areas, including rudders, stern tubes and intake gratings. Green algae and barnacles were most frequently sampled among vessels, but hydroids, bryozoans, bivalves and ascidians were also recorded. One vessel had 20 different species in its fouling assemblage, including non-native species (already established in San Francisco Bay) and mobile species that were not detected in visual surveys. In contrast to other studies, dry dock block areas did not support many organisms, despite little antifouling deterrence in some cases. Comparisons with previous studies suggest that the accumulation of fouling on containerships may be lower than on other ship types (eg bulkers and general cargo vessels), but more data are needed to determine the hierarchy of factors contributing to differences in the extent of macrofouling and non-native species vector risks within the commercial fleet.
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The role of containerships as transfer mechanisms of marine biofouling species.
Biofouling, 2009Co-Authors: Ian C. Davidson, Christopher W. Brown, Mark D. Sytsma, Gregory M. RuizAbstract:Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their Submerged Surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large Surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had Submerged Surface areas of >7000 m(2), and fouling coverage on this area was estimated to be
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the role of containerships as transfer mechanisms of marine biofouling species
Biofouling, 2009Co-Authors: Ian C. Davidson, Christopher W. Brown, Mark D. Sytsma, Gregory M. RuizAbstract:Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their Submerged Surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large Surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had Submerged Surface areas of >7000 m2, and fouling coverage on this area was estimated to be
Francesco Di Natale - One of the best experts on this subject based on the ideXlab platform.
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Surface-to-bed heat transfer in fluidised beds of fine particles
Powder Technology, 2009Co-Authors: Francesco Di Natale, Amedeo Lancia, Roberto NigroAbstract:Abstract This work reports experimental results on the heat transfer between a fluidised bed of fine particles and a Submerged Surface. Experiments have been carried out using different bed materials (polymers, ballotini, corundum, carborundum and quartz sand) with Archimedes number between 2 and 50. Dry air at ambient pressure and temperature has been used as fluidising gas. Three different exchange Surfaces, namely a sphere and two cylinders with different base diameter and same height, have been used. Experimental results show that the heat transfer coefficient increases with particle Archimedes number and is almost independent from particle thermal conductivity for K p / K g > 30. Finally, the comparison of heat transfer coefficient for the different Surfaces shows that the effect of the Surface geometry may account for a 30% variation in the heat transfer coefficient, with higher differences occurring for coarser particles.
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A single particle model for Surface-to-bed heat transfer in fluidized beds
Powder Technology, 2008Co-Authors: Francesco Di Natale, Amedeo Lancia, Roberto NigroAbstract:This paper presents a semi empirical single particle model for the description of heat transfer coefficient between a Submerged Surface and a fluidized bed. The model is applied to several experimental data and gives a satisfactory description of the effect of pressure, temperature and bed material properties on the heat transfer coefficient either in bubbling or slugging fluidized beds. The model considers the averaged Surface void fraction as the only regression parameter for the description of experimental data. Surface void fraction results to be a function of Archimedes number and minimum fluidization bed voidage and its value is consistent with the numerical and experimental data reported in literature.
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Surface-to-bed heat transfer in fluidised beds: Effect of Surface shape
Powder Technology, 2007Co-Authors: Francesco Di Natale, Amedeo Lancia, Roberto NigroAbstract:In recent times, the possible application of fluidisation technologies to the Surface treatments of engineering materials becomes a subject of growing interest both for manufacturing and chemical industries. Heat and mass transfer rates between the Surface and the fluidised bed strongly influence the performance of the Surface treatment. Experimental results of heat transfer between a Submerged Surface and a fluidised bed are presented in this article. This work is focused on the influence of bed material properties and Surface geometry on heat transfer coefficient. Experimental tests show that the heat transfer coefficient is notably affected by the shape of the immersed Surface resulting higher for Surfaces with better aerodynamic shape. An interpretative model, based on the dimensional analysis, has been used for the description of the experimental results.
Ian C. Davidson - One of the best experts on this subject based on the ideXlab platform.
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the role of containerships as transfer mechanisms of marine biofouling species
Biofouling, 2009Co-Authors: Ian C. Davidson, Christopher W. Brown, Mark D. Sytsma, Gregory M. RuizAbstract:Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their Submerged Surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large Surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had Submerged Surface areas of >7000 m(2), and fouling coverage on this area was estimated to be <17 m(2) per vessel, with zero biota detected on the hulls of many vessels. The outlying smaller vessel (4465 m(2)) had an estimated coverage of 90% on the hull and also differed substantially from the other ships in terms of its recent voyage history, shorter voyage range and slower speeds. Despite the low extent of fouling, taxonomic richness was high among vessels. Consistent with recent studies, a wide range of organisms were concentrated at more protected and heterogeneous (non-hull) niche areas, including rudders, stern tubes and intake gratings. Green algae and barnacles were most frequently sampled among vessels, but hydroids, bryozoans, bivalves and ascidians were also recorded. One vessel had 20 different species in its fouling assemblage, including non-native species (already established in San Francisco Bay) and mobile species that were not detected in visual surveys. In contrast to other studies, dry dock block areas did not support many organisms, despite little antifouling deterrence in some cases. Comparisons with previous studies suggest that the accumulation of fouling on containerships may be lower than on other ship types (eg bulkers and general cargo vessels), but more data are needed to determine the hierarchy of factors contributing to differences in the extent of macrofouling and non-native species vector risks within the commercial fleet.
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The role of containerships as transfer mechanisms of marine biofouling species.
Biofouling, 2009Co-Authors: Ian C. Davidson, Christopher W. Brown, Mark D. Sytsma, Gregory M. RuizAbstract:Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their Submerged Surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large Surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had Submerged Surface areas of >7000 m(2), and fouling coverage on this area was estimated to be
-
the role of containerships as transfer mechanisms of marine biofouling species
Biofouling, 2009Co-Authors: Ian C. Davidson, Christopher W. Brown, Mark D. Sytsma, Gregory M. RuizAbstract:Fouling of ships is an important historical and enduring transfer mechanism of marine nonindigenous species (NIS). Although containerships have risen to the forefront of global maritime shipping since the 1950s, few studies have directly sampled fouling communities on their Submerged Surfaces, and little is known about differences in the fouling characteristics among commercial ship types. Twenty-two in-service containerships at the Port of Oakland (San Francisco Bay, California) were sampled to test the hypothesis that the extent and taxonomic richness of fouling would be low on this type of ship, resulting from relatively fast speeds and short port durations. The data showed that the extent of macroorganisms (invertebrates and algae) was indeed low, especially across the large Surface areas of the hull. Less than 1% of the exposed hull was colonized for all apart from one vessel. These ships had Submerged Surface areas of >7000 m2, and fouling coverage on this area was estimated to be
Nils Kroger - One of the best experts on this subject based on the ideXlab platform.
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a tyrosine rich cell Surface protein in the diatom amphora coffeaeformis identified through transcriptome analysis and genetic transformation
PLOS ONE, 2014Co-Authors: Matthias T Buhmann, Nicole Poulsen, Jennifer Klemm, Matthew R Kennedy, David C Sherrill, Nils KrogerAbstract:Diatoms are single-celled eukaryotic microalgae that are ubiquitously found in almost all aquatic ecosystems, and are characterized by their intricately structured SiO2 (silica)-based cell walls. Diatoms with a benthic life style are capable of attaching to any natural or man-made Submerged Surface, thus contributing substantially to both microbial biofilm communities and economic losses through biofouling. Surface attachment of diatoms is mediated by a carbohydrate- and protein- based glue, yet no protein involved in diatom underwater adhesion has been identified so far. In the present work, we have generated a normalized transcriptome database from the model adhesion diatom Amphora coffeaeformis. Using an unconventional bioinformatics analysis we have identified five proteins that exhibit unique amino acid sequences resembling the amino acid composition of the tyrosine-rich adhesion proteins from mussel footpads. Establishing the first method for the molecular genetic transformation of A. coffeaeformis has enabled investigations into the function of one of these proteins, AC3362, through expression as YFP fusion protein. Biochemical analysis and imaging by fluorescence microscopy revealed that AC3362 is not involved in adhesion, but rather plays a role in biosynthesis and/or structural stability of the cell wall. The methods established in the present study have paved the way for further molecular studies on the mechanisms of underwater adhesion and biological silica formation in the diatom A. coffeaeformis.
