Browsing by Subject "particulate matter"
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Item Study of heavy metal pollution and speciation in Buyak Menderes and Gediz river sediments(Elsevier Ltd, 2003) Akcay H.; Oguz A.; Karapire C.In this study, two economically important rivers of Turkey, Gediz and Buyuk Menderes (BM) are studied to determine their environmental pollution levels. An old analytical procedure involving sequential chemical extraction is improved and used for the partitioning of particulate trace metals (Cu, Co, Cr, Mn, Fe, Zn, Pb and Ni). Cationic and anionic Mn and Cr species with different phases are also determined by using leaching, extraction and ion exchange speciation processes. The sediment samples are analysed using graphic-furnace atomic absorption spectroscopy and differential pulse anodic stripping voltammeter. Experimental results obtained on five replicate samples of fluvial bottom surface sediments at the sampling points demonstrate that the relative standard deviation of the sequential extraction procedure is generally better than ±10%. The accuracy, determined by comparing total metal concentrations with the sum of the five sequential chemical extractions, is proved to be satisfactory. The detection limits established for three standard deviations of blank for different metals are identical and found to be 0.1mg/kg for sediment samples and 1ppb for water samples. The results show that the pollution levels are significant especially for Pb, Cr, Mn and Zn in the Gediz river and Co, Mn, and Zn in the BM river. Comparison between our results and the measurements outlined before industralization and the beginning of the intensive pesticide applications in agricultural fields (In: Broekaert et al., editors, Metal speciation in the environment, vol. 23. 1989. p. 601-11; A research on the environmental pollution in the agricultual fields and watering in the Aegean region, Ege University Research Project, No. 127 1988 (in Turkish); DSI Water Analyses Report, Ankara, 1985 (in Turkish)) show that the pollution in these rivers is probably originated from industrial, agricultural and domestic waste discharges. © 2002 Elsevier Science Ltd. All rights reserved.Item Mixed convection in a PCM filled cavity under the influence of a rotating cylinder(Elsevier Ltd, 2020) Selimefendigil F.; Öztop H.F.In this study, mixed convection in a phase change material filled square cavity under the effect of a rotating cylinder was numerically investigated. The vertical walls are kept at constant temperatures while the horizontal walls are adiabatic. The effects of angular rotational speed of the cylinder (between −7.5 and 7.5), vertical location of the cylinder (between 0.25 and 0.75) and two different cylinder sizes (0.05 and 0.1) on the fluid flow and heat transfer were numerically investigated in detail. It was observed that rotating cylinder parameters can be used to control the heat transfer and melting process in the cavity. For angular rotational speed of cylinder at (ω=7.5) compared to motionless cylinder (ω=0), average heat transfer enhances by about 22.50%. The highest value of the average heat transfer for different vertical locations of the cylinder depends on the angular rotational speed of the cylinder. The average Nusselt number increases 10% when a large cylinder is used compared to smaller one for clockwise rotation of the cylinder and it is 19.8% for the stationary cylinder configuration. © 2019 International Solar Energy SocietyItem Air pollution and COVID-19: Clearing the air and charting a post-pandemic course: A joint workshop report of ERS, ISEE, HEI and WHO(European Respiratory Society, 2021) Andersen Z.J.; Hoffmann B.; Morawska L.; Adams M.; Furman E.; Yorgancioglu A.; Greenbaum D.; Neira M.; Brunekreef B.; Forastiere F.; Rice M.B.; Wakenhut F.; Coleen E.; Boogaard H.; Gehring U.; Melén E.; Ward B.; de Matteis S.[No abstract available]