Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7755
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Article Citation - WoS: 44Citation - Scopus: 54Protection of Marble Surfaces by Using Biodegradable Polymers as Coating Agent(Elsevier, 2009) Ocak, Yılmaz; Sofuoğlu, Aysun; Tıhmınlıoğlu, Funda; Böke, HasanBiodegradable polymers have been replaced over the synthetic polymers in many applications due to their good properties such as reversibility and biodegradability. Therefore they allow new treatment on the surface of the material to be protected and they fulfil the principles generally accepted by the International Conservation Community of Historic Monuments and Buildings. In this study, the efficiency of four different biodegradable polymers as protective coatings on marble-SO2 reaction was investigated. The polymers used were zein, chitosan, polyhydroxybutyrate (PHB), and poly-l-lactide (PLA). The mineralogical composition, bulk density and porosity of uncoated marble were determined. The water vapor permeability, water absorption by capillary forces, surface wettability, and color alteration of uncoated and coated marbles were measured. For sulphation reaction, marble slabs were coated with these polymers and then they were exposed at nearly 8 ppm SO2 concentration at 100% relative humidity conditions together with uncoated ones in a reaction chamber for several days for testing their protection efficiency. The extent of reaction was determined by leaching of gypsum formed on the marble surfaces in deionized water and then determining the sulphate content by ion chromatography. The protection efficiency of polymer treatments was expressed as comparing the gypsum crust thickness of the coated and uncoated marble plates. The comparison among the polymers showed that the surface hydrophobicity, water capillary absorption and structure of polymer would be important factors affecting the protection efficiency. The use of high molecular weight PLA (HMWPLA) polymer on marble surfaces provided significant protection up to 60% which was indicated that HMWPLA polymer seems to be promising polymer as protective coating agent in reducing gypsum formation on marble surfaces in the polluted environment.Article Citation - WoS: 94Citation - Scopus: 96Short-Term Variation in Ambient Concentrations and Gas/Particle Partitioning of Organochlorine Pesticides in Izmir, Turkey(Elsevier Ltd., 2004) Sofuoğlu, Aysun; Çetin, Eylem; Bozacıoğlu, Sevde Seza; Şener, Gaye Devrim; Odabaşı, MustafaTwenty successive daytime and nighttime air samples were collected and analyzed for 23 currently used and/banned organochlorine pesticides (OCPs) between 14 and 23 May 2003 in Izmir, Turkey. Average individual OCP concentrations ranged from 5±4pgm-3 (p,p′- dichlorodiphenyldichloroethane) to 391±306pgm-3 (chlorpyrifos) and they were within the ranges previously measured at different sites. Most of the OCPs did not exhibit strong diurnal cycling. The temperature dependence of gas-phase atmospheric concentrations of OCPs investigated using Clausius-Clapeyron plots was statistically significant for β-HCH and endosulfan sulfate (p<0.1) and was not significant for other compounds (0-21% of the variability in their gas-phase concentrations). In addition to temperature, the effect of wind speed and direction was also investigated using multiple linear regression analysis and these three parameters together explained the 2% (aldrin) to 72% (endosulfan II) of the variability in gas-phase OCP concentrations. Results of the multiple regression analysis indicated that wind speed was a statistically significant factor for most of the OCPs and wind direction was important for some compounds. The temperature-dependent diurnal cycling of most OCPs was probably masked by the higher wind speeds observed during daytime periods with high temperatures, different source sectors and ongoing sources. The lack of correlation for heptachlor, aldrin, p,p′-dichlorodiphenyldichloroethylene (p-p′-DDE), and p,p′-dichlorodiphenyltrichloroethane (p-p′-DDT) with temperature, wind speed and direction suggested that their concentrations were affected by long-range transport. The partitioning of OCPs between particle and gas phases was investigated and compared to KOA (octanol/air partition coefficient) absorption model. The overall agreement between experimental and modeled logKp (gas/particle partition coefficient) values was good (p<0.01, slope=0.94). Prediction of absorption model for particulate percentages was excellent for β-HCH, endosulfan I, and p-p′-DDT. However, the model underpredicted the particulate percentages for α,γ-HCHs, chlorpyrifos, and dieldrin, and overpredicted those for p-p′-DDE.Article Citation - WoS: 71Citation - Scopus: 76Temperature Dependence of Gas-Phase Polycyclic Aromatic Hydrocarbon and Organochlorine Pesticide Concentrations in Chicago Air(Elsevier Ltd., 2001) Sofuoğlu, Aysun; Odabaşı, Mustafa; Taşdemir, Yücel; Khalili, Nasrin R.; Holsen, Thomas M.The temperature dependence of gas-phase atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides measured in Chicago, IL between June and October 1995 were investigated using plots of the natural logarithm of partial pressures (lnP) vs. reciprocal mean temperatures (1/T). For the eight lowest molecular weight PAHs, temperature dependence was statistically significant (at the 95% confidence level) and temperature accounted for 23-49% of the variability in gas-phase concentrations. The relatively higher slopes for most of the PAHs suggested that volatilization from local sources and short-range transport influenced their concentrations. For pesticides, temperature dependence was statistically significant for DDD and for trans-nonachlor (at the 95% and 90% confidence levels), and was not statistically significant for the other five compounds (2-18% of the variability in their gas-phase concentrations). The relatively lower slopes for individual pesticides suggested that they have mostly non-urban and distant sources.Results of back trajectory analyses suggested that the region, southwest of Chicago, might be an important local or regional source sector for PAHs and organochlorine pesticides. No statistically significant relationship was observed between wind speed and PAH or pesticide concentrations. None of the variables (temperature, wind speed, wind direction, local and regional sources) could fully explain the variation in their concentrations measured in Chicago, therefore, this variation can be attributed to the combined effect of those factors.