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| Dekov, V.m.; Egueh, N. M.; Kamenov, G. D.; Bayon, G.; Lalonde, S.v.; Schmidt, M.; Liebetrau, V.; Munnik, F.; Fouquet, Yves; Tanimizu, M.; Awaleh, M. O.; Guirreh, I.; Le Gall, B.. |
| Carbonate chimney-like deposits up to 60 m high are scattered or arranged in rows at the shores of a desiccating hypersaline and alkaline lake from a continental rift setting (Lake Abhé, Afar Rift, Djibouti). The chimneys formed sub-aqueously in the lake water body at a higher water level than observed today. Alternating calcite and low-Mg calcite + silica concentric layers compose the chimney structures. Mineralogical and geochemical investigations of the chimneys, lake water, and hot spring (hydrothermal) fluids suggest that the chimneys are a result of rapid carbonate precipitation during the mixing of hydrothermal fluids with lake water. In contrast to the hot spring fluid, lake water is enriched in HREE and possesses a pronounced positive Ce anomaly,... |
| Tipo: Text |
Palavras-chave: Carbonate; Chimney; Continental rift; H-C-O-Ca-Sr-Nd-Pb-Th-U-isotopes; Hydrothermalism. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00206/31762/30172.pdf |
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| Dekov, V. M.; Lalonde, Stefan; Kamenov, G. D.; Bayon, Germain; Shanks, W. C., Iii; Fortin, D.; Fouquet, Yves; Moscati, R. J.. |
| An inactive vent field comprised of dead chimneys was discovered on the ultrafast East Pacific Rise (EPR) at 18°S during the research campaign NAUDUR with the R/V Le Nadir in December 1993. One of these chimneys was sampled, studied and found to be largely composed of silica-mineralized bacterial-like filaments. The filaments are inferred to be the result of microbial activity leading to silica (± Fe-oxyhydroxide) precipitation. The chimney grew from the most external layer (precipitated 226 ± 4 yr. B.P.) towards the central chimney conduit. Hydrothermal activity ceased 154 ± 13 yr. B.P. and the chimney conduit was completely sealed. Mixing between an end-member hydrothermal fluid and seawater explains the Sr–Nd isotopic composition of the chimney.... |
| Tipo: Text |
Palavras-chave: Chimney; C-O-Si-Sr-Nd-Pb-Th-U isotopes; Hydrothermal; Seafloor; Silica. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00280/39143/37698.pdf |
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| Kumi, Francis. |
| The postharvest losses of agricultural produce in Ghana and other developing countries is high. Efforts to promote shelf-life extension of the fresh produce is centred around temperature and moisture management. Moisture control by drying is suited to a number of crops as it inhibits microbial decay and physiological processes of deterioration. However, there are often inefficient drying infrastructure in developing countries. Thus, the focus of this research was to structurally modify a chimney solar dryer originally designed by the Horticulture Innovation Laboratory of the University of California, Davis and include sea pebbles in the collector base to enhance its heating system and drying performance. A computational fluid dynamics analysis using ANSYS... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chimney; Dryer; Computational fluid dynamics; Simulation; Moisture content. |
| Ano: 2022 |
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/7005 |
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