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Quantifying water quality and flow in multi-branched urban estuaries for a rainfall event with mass balance method

Water Science and Engineering 2020年第4期13卷 317-328页

作者： joan cecilia casila Gubash Azhikodan Katsuhide Yokoyama College of Engineering and Agro-Industrial Technology University of the Philippines Los BanosLos Banos 4031Philippines Department of Civil and Environmental Engineering Tokyo Metropolitan UniversityTokyo 192-0397Japan

In this study,field observations were conducted after a heavy rainfall event in the Sumida and Shakujii rivers in Tokyo,Japan.The flow dynamics and fluxes of salt,suspended sediment(SS),and dissolved oxygen(DO)were investigated with the mass balance method.The fractions of fresh water and saltwater in seaward and landward flows were separated.The maximum salt flux in the Shakujii River was 53.8 kg/s during the flood tide,and those in the Sumida River were 680.3 kg/s at the upstream station and 703.7 kg/s at the downstream station.The trends of SS and DO fluxes were similar in both rivers.In the Shakujii River,the highest SS(3.1 kg/s)and DO(0.4 kg/s)fluxes appeared during the flood tide after rainfall.In the Sumida River,the maximum SS fluxes(6.1 and 6.3 kg/s at the upstream and downstream stations,respectively)and DO fluxes(1.15 and 1.21 kg/s at the upstream and downstream stations,respectively)appeared during the ebb tide.The mass balance method was used to estimate discharge,salinity,SS concentration,and DO concentration at a station with missing data.The results show that the estimated salinity and SS concentration had a significant correlation with the on-site observations,with correlation coefficients(R)of 0.950 and 0.835,respectively,but not for DO concentration(R?0.638).The disparity between the computed and measured data may be explained by the differences in velocity,salinity,topography,sedimentation,and the presence of organic matter.The analysis based on the advective salt transport components found a lower salt flux per unit width in the Shakujii River(0.36 kg/(m·s))in comparison with that in the Sumida River(2.88 kg/(m·s)).This indicates a higher probability for salt retention in the Shakujii River.©2020 Hohai University.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://***/licenses/by-nc-nd/4.0/).

关键词： Mass balance Water quality Flow Salt transport Sumida River Shakujii River Estuary

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Implications of turbulent shear on clay floc break-up along the Atlantic estuary(Bouregreg),Morocco

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International Journal of Sediment Research 2022年第2期37卷 248-257页

作者： Krishnamoorthy Lakshmi Ammal Priya Soufiane Haddout joan cecilia Catubig casila Department of Civil Engineering TKM College of Engineering Department of Physics Faculty of Science Ibn Tofail University Land and Water Resources Division IABE CEAT University of the Philippines Los Ba?os

Water depth,salinity,current,and suspended sediment concentration(SSC) were measured along with the grain size distribution of bed sediment along an estuarine longitudinal section.The floc size increased with increase in the percentage of clay and silt,while decreased with increase in the percentage of sand content of bed sediment.The turbulent shear,G,had a direct effect on floc size with its value increasing with increase in G up to a G value of 15 s,while an inverse relation existed between floc size and G at higher G(C> 15 s).Further,higher turbulence enabled sand to get resuspended and cause additional shear leading to the break-up of flocs.An attempt was made to modify G to account for the combined effect of water turbulence(C) and shear imparted by sand(C) and the impact of the modification of G on the predictability of floc size was evaluated.A new model was developed which explains floc size in terms of sediment concentration(C),salinity gradient(S),and G for different scenarios based on the value of G.Sensitivity analysis was done for observed floc size(FS) and predicted floc size using four approaches:(Ⅰ) FS β C~χ;(Ⅱ) FS α C~χS;(Ⅲ) FS α C~χSG~z for G 15 s; and(Ⅳ) FS α C~χSGfor G> 15 sand G=G+G,where x,y,and z are determined by calibration.It was observed that the predictability of the floc size improved when the turbulence was modified to account for shear imparted by sand so that the coefficient of determination was increased from 0.78 for model Ⅲ to 0.89 for model Ⅳ.Further,the settling velocity was expressed as a function of suspended sediment concentration,turbulent shear,and salinity gradient.The predictability of settling velocity was improved(R~2 increased from 0.77 to 0.86) when the additional turbulence created by sand was incorporated in the non-dimensional empirical equation.The study highlights the influence of sand in causing the break-up of flocs and suggests that for turbulence shear values high enough to resuspend sand,and G has to be modified to account for th

关键词： Floc size Settling velocity Turbulent shear Non-cohesive sediment Bouregreg estuary Morocco

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Tanning capacityof Tessmannia burttii extracts:thepotentialeco-friendlytanning agents fortheleatherindustry

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Journal of Leather Science and Engineering 2021年第1期3卷 149-157页

作者： cecilia R.China Stephen S.Nyandoro joan J.E.Munissi Mihayo M.Maguta Michael Meyer Michaela Schroepfer Division of Textile and Leather Technologies Tanzania Industrial Research and Development OrganizationP.O.Box 2355Dar es SalaamTanzania Chemistry Department College of Natural and Applied SciencesUniversity of Dar es SalamP.O.Box 35061Dar es SalaamTanzania Department of Environmental Planning Institute of Rural Development Planning(IRDP)P.O.Box 138DodomaTanzania FILK-Research Institute of Leather and Plastic Sheeting Meißner Ring 1-509599 FreibergGermany

In the present study,the tannins from stem and root barks of Tessmannia burttii Harms(Caesalpiniaceae),a plant species abundantly growing in Tanzania and other parts of Africa,were investigated for their suitability in hides tanning.Tannin powder was extracted at selected temperatures(30,50 and 80°C)and the influence of each temperature on the crosslinking capacity was evaluated.The interaction mechanism between hide powder collagen and the tannins was studied by Differential Scanning Calorimetry(DSC),trinitrobenzensulfonic(TNBS)acid assay and amino acid hydrolysis methods.Extraction temperatures showed low influence on crosslinking capacity of the tannins.However,extract obtained at 50°C exhibited best performance in terms of gap size between T onset and T peak.The stem bark extract yield was higher than that from the root bark,but both were within the recommended ranges.The tannin content(61%)of T.burttii stem bark extract was above recommended value(10%),whereas its total phenolic content and total flavonoic content were found to be above that of commercial Acacia mearnsii tannin.The study of cross-linking parameters as a function of pH showed cross-linking to occur via a covalent mechanism at the basic amino groups.However,the bonds were not resistant to acid hydrolysis.The observed interaction mechanism indicated that tannins from stem and root barks of T.burttii belong to the condensed tannin,similar to A.mearnsii(black wattle),a commercial tannin source that was used in this study as a reference.Findings from this study depict that T.burttii extracts are auspicious eco-friendly alternative source of vegetable tannins to overcome the use of chromium salts in the leather industry.

关键词： Tessmannia burttii Caesalpiniaceae Leather industry Vegetable tanning Tanning capacity

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Clinical Predictors of Prolonged Hospital Stay after Acute Stroke: Relevance of Medical Complications

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International Journal of Clinical Medicine 2012年第6期3卷 502-507页

作者： Adrià Arboix joan Massons Luís García-Eroles cecilia Targa Montserrat Oliveres Emili Comes Cerebrovascular Division Department of Neurology Capio-Hospital Universitari del Sagrat Cor Universitat de Barcelona Barcelona Spain Unit of Organization Planning and Information Systems Consorci Sanitari del Maresme Badalona Spain

Purpose: This study aims to identify clinical predictors of prolonged hospital stay after acute stroke based on data collected from a prospective hospital-based acute stroke registry. Methods: All patients with first-ever ischemic stroke and primary intracerebral hemorrhage included in the Sagrat Cor Hospital of Barcelona stroke database over a 17-year period were assessed. Prolonged hospital stay was defined as hospitalization for longer than 12 days after admission. Demographic data, cardiovascular risk factors, clinical factors, neuroimaging findings, and outcome were compared in patients hospitalized for more or less than 12 days. Logistic regression analysis was used to assess the independent influence of statistically significant variables in the bivariate analysis and duration of hospitalization. Results: Of a total of 3112 acute stroke patients included in the study, prolonged hospital stay was recorded in 1536 (49.4%). Male sex (OR = 1.16), limb weakness (OR = 1.79), vascular complications (OR = 2.68), urinary complications (OR = 2.56), and infectious complications (OR = 1.78) were independently associated with longer stay, whereas symptom free at discharge (OR = 0.45) and lacunar infarction (OR = 0.43) were inversely associated with prolonged hospitalization. Conclusion: In-hospital medical complications (vascular, urinary, and infectious) are relevant factors influencing duration of hospitalization after acute stroke. Therefore, prevention of potentially modifiable risk factors for medical complications is an important aspect of the early management of patients with stroke.

关键词： Medical Complications Length of Hospital Stay Stroke

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