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: 23Citation - Scopus: 22Exposure To Particulate Matter in a Mosque(Elsevier Ltd., 2012) Ocak, Yılmaz; Kılıçvuran, Akın; Eren, Aykut Balkan; Sofuoğlu, Aysun; Sofuoğlu, Sait CemilIndoor air quality in mosques during prayers may be of concern for sensitive/susceptible sub-groups of the population. However, no indoor air pollutant levels of potentially toxic agents in mosques have been reported in the literature. This study measured PM concentrations in a mosque on Friday when the mid-day prayer always receives high attendance. Particle number and CO 2 concentrations were measured on nine sampling days in three different campaigns before, during, and after prayer under three different cleaning schedules: vacuuming a week before, a day before, and on the morning of the prayer. In addition, daily PM 2.5 concentrations were measured. Number concentrations in 0.5-1.0, 1.0-5.0, and>5.0μm diameter size ranges were monitored. In all campaigns the maximum number concentrations were observed on the most crowded days. The lowest number concentrations occurred when vacuuming was performed a day before the prayer day in two of the three size ranges considered. PM 2.5 concentrations (four-hour samples that integrated before, during, and after the prayer) were comparable to the other indoor environments reported in the literature. CO 2 concentrations suggested that ventilation was not sufficient in the mosque during the prayers. The results showed that better ventilation, a preventive cleaning strategy, and a more detailed study are needed.Master Thesis Protection of the Marble Monument Surfaces by Using Biodegradaple Polymers(Izmir Institute of Technology, 2007) Ocak, Yılmaz; Sofuoğlu, AysunThe deterioration of historic buildings and monuments constructed by marble has been accelerated in the past century due to the effects of air pollution. The main pollutant Sulphur dioxide (SO2) reacts with marble composed primarily of calcite (CaCO3), the firs step of decay which called gypsum (CaSO4.2H2O) crust is formed and this process can be accelerated when the surfaces exposed to the rain.In this study, the possibilities of slowing down the SO2-marble reactions were investigated by coating the surface of marble with some bio-degradable polymers: zein, chitosan, polyhydroxybutyrate (PHB) and polylactic acid (PLA) as protective agents.Uncoated control marbles and biodegradable polymer coated marbles were exposed at nearly 8 ppm SO2 concentration at 100 % relative humidity conditions in a reaction chamber for several days. The extent of reaction was determined by leaching sulphate from the marble surface into deionized water and measuring the total concentration of sulphate with ion chromatography (IC). Then, gypsum crust thickness, polymers % protection factor and average deposition velocity were calculated. Concurrently, the ratio and amount of calcium sulfite hemihydrate (CaSO3.H2O)and gypsum (CaSO4.2H2O) were determined by FT-IR analysis. The surface morphology of SO2 exposed marble to distinguished calcium sulfite hemihydrate and gypsum crystals were determined by Scanning Electron Microscope (SEM).The results of the study showed that SO2-calcite reaction increased in the use of zein, glycerol added zein and chitosan polymers on the surface of marble. While, PHB treated marble surfaces had 5 % increases in the protection factor. The low molecular weight PLA protection factor was 45 % after 85 days exposure. Similar results were observed when the high molecular weight of PLA used. The protection was extended to more than 90 days having 60 % protection factor.