Yıldırım, Yılmaz | Bayramoğlu, Mahmut | Tecer, Lokman Hakan | Yalçın, Gültekin

Bildiri | 2004 | AIR POLLUTION MODELING AND ITS APPLICATION XVI16 , pp.559 - 567

Air pollution continues to be a major problem in many countries. Mathematical models are useful in relating emissions to air quality under a variety of meteorological conditions and source emission concentrations over an urban area. Meanwhile, the forecasting capability of sophisticated models is limited to very large and complex terrains. In this study, adaptive neuro-fuzzy logic method has been proposed to estimate the impact of meteorological factors on SO2 pollution levels. The model forecasts satisfactorily the trends in SO2 concentration levels, with performance between 78-90%.

Candan, Köse | Genç, Ayten

Bildiri | 2015 | WATER RESOURCES MANAGEMENT VIII196 , pp.505 - 512

In this study, vacuum filtration, coagulation-flocculation, electrocoagulation and centrifugation were applied to separate emulsified oils from water. Two different types of cutting oils (BOR and EAL) were used in the preparation of oil emulsions. BOR has smaller oil droplets than EAL when they are mixed by water. It was not possible to separate BOR from water by microfiltration but 81.7% removal efficiency was obtained for EAL. Alum and ferric chloride were used as coagulants and optimum coagulant dosages, mixing time and pH were determined by performing jar tests. When alum was used as the coagulant, the removal efficiencies for B . . .OR and EAL were 90% and 98%, respectively. In the case of ferric chloride, 98% oil removal was obtained for both emulsions. However, the optimum ferric chloride dosages were much higher than alum. The optimum alum and ferric chloride dosages for BOR emulsion were 0.83 g/L and 6 mg/L, respectively. In the case of EAL emulsion, the corresponding amounts were 4 mg/L and 8 mg/L. The flocculation time was determined around 45 minutes. In order to obtain 98% BOR removal, the emulsion was centrifuged at an angular velocity of 3000 rpm after the coagulation-flocculation process. On the other hand, when BOR and EAL were separated by electrocoagulation, 95% removal rates can be obtained for both oils applying 40 V difference to the aluminum electrodes for 35 minutes. According to the removal efficiencies obtained from the experiments and the preliminary cost analysis it can be concluded that the best method for separating emulsified oils from waters is the electrocoagulation Daha fazlası Daha az

Genç, Ayten | Ulupınar, Elif

Makale | 2010 | Transport in Porous Media84 ( 3 ) , pp.699 - 709

This study aimed to identify effects of pH on the transport of Pb2+ ions through a saturated silty-clayey soil layer by using advection-dispersion equation (ADE). The predictive accuracy of the solution of ADE depends on the proper determination of the retardation by adsorption and, therefore, the adsorption mechanism of lead onto silty-clayey soil was investigated first by performing batch equilibrium experiments. These results showed that the sorption mechanism of lead onto silty-clayey soil depended on pH and could be best described by the Langmuir isotherm. Based on the results of the sequential experiments, it was also conclude . . .d that the pH dependent charges in silty-clayey soil were mainly associated with the surfaces of carbonates and the specific adsorption of lead ions. The numerical solutions of the combined form of ADE with the Langmuir isotherm indicated that the migration profiles of lead in silty-clayey soil were a strong function of the parameters of the Langmuir isotherm rather than the infiltration velocity. © 2010 Springer Science+Business Media B.V Daha fazlası Daha az

Durgun D. | Genç, Ayten

Makale | 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

Özdemir, Kadir | Güngör, Ömer

Makale | 2018 | Water SA44 ( 4 ) , pp.680 - 690

This research developed models using the multiple linear regression technique for prediction of trihalomethane (THM) removal from chlorinated drinking water sources through a combination of a coagulation process with carbon nanotubes (CNTs). Terkos Lake water (TLW), Buyukçekmece Lake water (BLW) and Ulutan Lake water (ULW) samples were coagulated by a conventional coagulant (alum) and increasing doses of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) with the addition of alum. Also, chlorination experiments were conducted with water reservoirs from TLW, BLW and ULW, with different water quality re . . .garding bromide concentration and organic matter content. The factors studied affecting THM removal were contact time, chlorine dose, coagulation process, total organic carbon (TOC), and specific ultraviolet absorbance (SUVA). Statistical analysis of the results focused on the development of multiple regression models, as Models 1 and 2, for predicting total trihalomethane (TTHM) based on the use of contact time, SWCNTs and MWCNTs doses, chlorine dose and TOC. When the two models were compared, Model 1 proved best suited to describe THM removal for the three water sources. The developed models provided satisfactory estimations of THM removal; the model regression coefficients for Models 1 and 2 were 0.88 and 0.77, respectively. Furthermore, the root-mean-square error (RMSE) values of 0.083 and 0.126 confirm the reliability of the two models. The results show that THM removal can be simply predicted by using the multiple linear regression technique in chlorinated drinking water sources. © 2018, South African Water Research Commission. All rights reserved Daha fazlası Daha az

Kobya, Mehmet | Demirbaş, Erhan | Demircioğlu, Nesli | Yıldırım, Yılmaz | Yıldız, Şevki Yalçın

Makale | 2004 | Desalination160 ( 3 ) , pp.253 - 262

Coupled transport of thiocyanate ions through a liquid membrane containing quaternary ammonium chloride salts in chloroform was examined. The influences of the carrier type in the membrane phase on the coupled transport of thiocyanate ions were investigated. The kinetics of the coupled transport were analyzed in the formalism of two consecutive irreversible first-order reactions and the kinetic parameters (k1d, k2m, k2a, Rmmax, tmax, Jdmax, Jamax,) were also calculated. For the coupled transport of thiocyanate ions, quaternary ammonium chloride salts having different carbon atom numbers (Cn) used as carriers were found to increase t . . .hiocyanate ions transport efficiency with increasing carbon atom numbers. Tetradecyl trimethylammonium chloride (TDTMACl), hexadecyl trimethylammonium chloride (HDTMACl), and tetraoctyl ammonium chloride (TOACl) were found to be the most effective carrier types for transport of thiocyanate ions when Cn is greater than 16. The activation energies for maximum membrane entrance and exit fluxes were calculated as 32.45 kJ/mol and 34.75 kJ/mol, respectively. The values of the activation energy indicate that the process is controlled by species diffusion Daha fazlası Daha az

Altın, Ahmet | Tecer, Selcen | Tecer, Lokman | Altın, Süreyya | Kahraman, Bekir Fatih

Bildiri | 2014 | 4TH WORLD CONFERENCE ON LEARNING TEACHING AND EDUCATIONAL LEADERSHIP (WCLTA-2013)141 , pp.1208 - 1214

In this study, secondary school students' awareness of environmental issues and problems and the level of their active participation in environmental activities have been identified, and the effects of some factors as family school and media on their environmental awareness and active participation have been investigated. The study was carried out in Balikesir city centre by conducting a survey on senior students consisting of 6 classes from three secondary schools which have different demographic and socio-economic levels. The results of the study showed a high level of environmental awareness among participant students. However, i . . .t is understood that environmental disclosures made in schools are insufficient and the participation level of students to environmental activities is low. Students rather gain experiences in the field of environment from mass media (i.e. audio, printed and visual media). It is revealed that female students have a higher level of environmental awareness and active participation level. In addition, when family income and family education level increases, environmental awareness and active participation level of students also increases. (C) 2014 Published by Elsevier Ltd Daha fazlası Daha az

Özölçer, İsmail Hakkı | Yıldırım, Yılmaz | Büyüksalih, Gürcan | Çapar, Ömer Faruk | Öztürk, Berna

Bildiri | 2005 | Proceedings of the 7th International Conference on the Mediterranean Coastal Environment, MEDCOAST 20051 , pp.83 - 94

Zonguldak is located on the Northwest coast of Turkey on the Black Sea. The population of the city is 106 000 and it is a coastal city which has got natural beauty and econemically influenced coal and steal. Zonguldak region is confronted with problems of the coastal engineering and management from Eregli to Filyos province. Main problems are shipyards and filling area, uncontrolled solid waste area on the sea side, damages result from sea storm, and getting shallow and polluted basin and increasing of ship traffic at Zonguldak Harbor. At the Zonguldak coasts, pollution comes from domestic wastes and Çatalagzi Thermal Power Plant. I . . .n this study, these problems have been investigated from point of coastal management and suitable solutions are presented Daha fazlası Daha az

Genç, Ayten | Bakırcı, Büşra

Makale | 2015 | Water Science and Technology71 ( 8 ) , pp.1196 - 1202

The effect of pulsed voltage application on energy consumption during electrocoagulation was investigated. Three voltage profiles having the same arithmetic average with respect to time were applied to the electrodes. The specific energy consumption for these profiles were evaluated and analyzed together with oil removal efficiencies. The effects of applied voltages, electrode materials, electrode configurations, and pH on oil removal efficiency were determined. Electrocoagulation experiments were performed by using synthetic and real wastewater samples. The pulsed voltages saved energy during the electrocoagulation process. In cont . . .inuous operation, energy saving was as high as 48%. Aluminum electrodes used for the treatment of emulsified oils resulted in higher oil removal efficiencies in comparison with stainless steel and iron electrodes. When the electrodes gap was less than 1 cm, higher oil removal efficiencies were obtained. The highest oil removal efficiencies were 95% and 35% for the batch and continuous operating modes, respectively. © IWA Publishing 2015 Daha fazlası Daha az

Özdemir, Kadir | Yıldırım, Yılmaz | Toröz, İsmail | Uyak, Vedat

Makale | 2015 | Asian Journal of Chemistry27 ( 3 ) , pp.984 - 990

This research developed models using multiple linear regression analysis for the prediction of trihalomethane formation in coagulated Istanbul drinking water sources. The power-law model (model 1), using only ?UV272 as the designed parameter, proved the best model to describe the formation of trihalomethane. The other model (model 2), included pH, total organic carbon, chlorine dosages, ultraviolet absorbance at 254 nm (UV254), specific ultraviolet absorbance (SUVA) and differential absorbance at 272 nm (?UV272). The root-meansquare error (RMSE), normalization mean square error (NMSE), regression coefficient (R2) and index of agreem . . .ent (IA) were used as statistical variables to evaluate the model performance. The better prediction results were obtained by model 1 for root-mean-square error, normalization mean square error, R2 and index of agreement as 9.14, 0.015, 0.95 and 0.99, respectively. © 2015, Chemical Publishing Co. All rights reserved Daha fazlası Daha az

Yıldırım, Yılmaz | Bayramoğlu, Mahmut

Makale | 2006 | Chemosphere63 ( 9 ) , pp.1575 - 1582

Air pollution is a growing problem arising from domestic heating, high density of vehicle traffic, electricity production, and expanding commercial and industrial activities, all increasing in parallel with urban population. Monitoring and forecasting of air quality parameters in the urban area are important due to health impact. Artificial intelligent techniques are successfully used in modelling of highly complex and non-linear phenomena. In this study, adaptive neuro-fuzzy logic method has been proposed to estimate the impact of meteorological factors on SO2 and total suspended particular matter (TSP) pollution levels over an urb . . .an area. The model forecasts satisfactorily the trends in SO2 and TSP concentration levels, with performance between 75-90% and 69-80 %, respectively. © 2005 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Özdemir, Kadir | Toröz, İsmail | Uyak, Vedat

Makale | 2013 | The Scientific World Journal2013 , pp.1575 - 1582

In this study, the changes in UV absorbance of water samples were characterized using defined differential UV spectroscopy (DUV), a novel spectroscopic technique. Chlorination experiments were conducted with water samples from Terkos Lake (TL) and Büyükçekmece Lake (BL) (Istanbul, Turkey). The maximum loss of UV absorbance for chlorinated TL and BL raw water samples was observed at a wavelength of 272 nm. Interestingly, differential absorbance at 272 nm (? UV 272) was shown to be a good indicator of UV absorbing chromophores and the formation of trihalomethanes (THMs) resulting from chlorination. Furthermore, differential spectra of . . . chlorinated TL waters were similar for given chlorination conditions, peaking at 272 nm. The correlations between THMs and ? UV 272 were quantified by linear equations with R 2 values >0.96. The concentration of THMs formed when natural organic matter is chlorinated increases with increasing time and pH levels. Among all THMs, CHCl3 was the dominant species forming as a result of the chlorination of TL and BL raw water samples. The highest chloroform (CHCl3), dichlorobromomethane (CHCl 2Br), and dibromochloromethane (CHBr2Cl) concentration were released per unit loss of absorbance at 272 nm at pH 9 with a maximum reaction time of 168 hours and Cl2/dissolved organic carbon ratio of 3.2. © 2013 Kadir Özdemir et al Daha fazlası Daha az