Genç, Ayten

Article | 2009 | Turkish Journal of Engineering and Environmental Sciences33 ( 1 ) , pp.73 - 81

The membrane potentials for asymmetric membranes where fixed charges varied linearly with position were evaluated from the numerical solutions of Nernst-Planck flux and Donnan potential equations. The evaluated membrane potentials were compared with the results obtained from the conventional TMS theory where the fixed charge concentration in the membrane was assumed to be uniform. In the comparison, the number of fixed charges was kept constant by defining an average for the fixed charge concentration. The numerical results showed that the membrane potential increased in magnitude when the distributions of fixed charges at the membr . . .ane-solution interfaces were unequal. In addition, the deviation from TMS theory increased more as the charge difference at the interfaces increased. © TÜBİTAK Daha fazlası Daha az

Durgun D. | Genç, Ayten

Article | 2009 | Energy34 ( 11 ) , pp.1976 - 1979

The production rates of furnace bottom ash in a pulverized coal-fired power plant were monitored for a two-year period and its variations with respect to coal properties were analyzed. The power plant was originally designed to fire the coal sludge generated from a washing process; however, the coal sludge and its mixture with low-rank bituminous coal have been started to be used as the main fuel with time. The results of the hardgrove grindability measurements have shown that the grinding properties of sludge or its mixtures could not be predicted based on proximate analysis (moisture, ash, carbon and volatile contents); it could o . . .nly be determined by experiments. The production rate of bottom ash in this particular power plant remained relatively insensitive to the high ash and moisture contents and could be estimated almost only by knowing the calorific value of the source coal. The evaluated dependency was linear. © 2009 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Altın, Süreyya | Peker, İbrahim | Demircioğlu, Nesli

Article | 2009 | Polish Journal of Chemistry83 ( 2 ) , pp.275 - 283

In this study, the effects of the different membrane diluents, carriers and variations in the concentrations of the carriers on the sodium ion transport were examined in bulk liquid membrane systems. The kinetic analysis of the sodium ion transport in the liquid membrane was performed through the implementation of two consecutive kinetic equations of first order irreversible reactions and the relevant kinetic parameters (k1, k2a, k2a, Rmax, tmax,) were determined. Toluene, n-hexane, 1-octanol, chloroform and dichloromethane were used as membrane diluents, while 18crown6 (18C6), dicyclohexyl 18crown6 (DC18C6) and dibenzo 18crown6 (DB . . .18C6) were used as carriers. The results reveal that the best sodium ion transport was realized when toluene-dichloromethane (90%-10%) was used as the membrane, and 1.10-3 M DB18C6 was used as the carrier Daha fazlası Daha az

Genç, Ayten | Tosun, İbrahim

Article | 2009 | Filtration9 ( 2 ) , pp.135 - 140

The variation in slurry concentration within the filter chamber during the startup of constant pressure filtration experiments and its effect on the cake length and filtrate volume are studied. Theoretical equations relating slurry concentration to cake length and filtrate volume are developed by using the equations of continuity together with the jump conditions at the cake-slurry interface. Comparison with experimental values indicates that the change in slurry concentration within the filter chamber, especially during the initial stages of filtration, should be taken into consideration in the evaluation of model parameters from e . . .xperimental data Daha fazlası Daha az

Altın, Ahmet | Özölçer, İsmail Hakkı | Yıldırım, Yılmaz

Article | 2009 | Fresenius Environmental Bulletin18 ( 11:00 AM ) , pp.2170 - 2180

In this study, water pollutions of the Black Sea in the Turkish costal region, particularly in the Zonguldak region, located in the western part of Turkey (southern part of the Black Sea), were investigated. Zonguldak province is a highly populated and industrialized region with two iron and steel factories, coal mining and a coal-powered energy plant. In this study; physical, chemical and bacteriological pollution of water, wastewater and surface water were conducted. The domestic and industrial wastewater discharges into 7 important surface water streams were investigated, and the effect of these discharges onto the water quality . . .of the streams and the Black Sea were discussed. This work is the first study evaluating water quality and pollution in detail in the northwest coastal region of Turkey Daha fazlası Daha az

Yıldırım, Yılmaz | Alkan, Mehmet | Oruç, Murat

Article | 2009 | Fresenius Environmental Bulletin18 ( 11 ) , pp.2072 - 2078

Power production using fossil fuels can bring significant adverse effects on the surrounding environment. In this study, detection of industrial ash turbidity from a coal-fueled power plant in marine water and its interaction with marine environment were evaluated using 3 satellite imageries. To this aim, e-Cognition v.4.0.6 software was utilized to perform detection, classification and comparison of the polluted area in the aquatic marine environment using Landsat-5 TM satellite imageries and Landsat-7 ETM + satellite imagery. Total polluted area, obtained from Landsat satellite imageries, was classified into 3 regions: highly poll . . .uted, moderately polluted and less polluted region, and their polluted field dimensions were evaluated to be 10.19 km2and 7.50 km2 for Landsat TM imageries as well as 37.73 km2 for Landsat ETM+ imagery. Total suspended solids (TSS) levels were determined as 2380±213 mg.L-1, 361±118 mg.L-1 and 57±24 mg.L-1for the highly, moderately and less polluted regions, respectively. This study may serve as a database for future comparisons to identify the trend of improvement or deterioration of coastal environment of Zonguldak Daha fazlası Daha az

Genç, Ayten | Chase, George | Foos, Annabelle

Article | 2009 | Water, Air, and Soil Pollution197 ( 01.Apr ) , pp.131 - 141

Manganese was removed from naturally polluted river sediment by applying an electrokinetic remediation technique. The sediment was alkaline and had 20% clay, which was mainly illite. The electrokinetic remediation experiments were performed by controlling pHs in the electrode cells and reverse electroosmotic flows were observed, i.e., water moved from cathode towards anode. Manganese accumulated in areas closer to cathode, however, other metals, such as copper, zinc and lead were mostly observed in the middle section of the sediment. As a result of reverse electroosmotic flow, the removal efficiencies of metals were low and the high . . .est removal efficiencies of manganese, copper and lead, were evaluated as 18%, 20% and 12%, respectively. Almost no removal of zinc was observed in all electrokinetic remediation experiments. © 2008 Springer Science+Business Media B.V Daha fazlası Daha az