Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 10Citation - Scopus: 11Liquefaction of Oak Wood Using Various Solvents for Bio-Oil Production(AMER CHEMICAL SOC, 2023) Öcal, Bulutcem; Yüksel Özşen, Aslı; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyRapidly increasing global energy demand resulting from the growing population and worldwide development has increased the consumption of limited fossil fuel. The usage causes severe environmental deterioration by CO2 emission, which has sparked interest in finding green, renewable, and sustainable alternative sources of energy. Bio-oil, derived from several biomasses via liquefaction, is a promising candidate to replace fossil fuels. Turkey's land (27%) is covered with forested areas (consisting of mostly oak trees). Therefore, it has great potential for cheap lignocellulosic feedstock forest residues from industrial applications and harvesting. In the present study, the thermal liquefaction of oak wood particles (OWP) was performed using various solvents in addition to water, namely, ethanol, 1-butanol, and 1,4-dioxane. The experiments were carried out in a batch reactor for 1 and 2 h residence times at different temperatures (210, 240, and 270 degrees C). Bio-oil samples obtained at 270 degrees C and a 1 h residence time determined as optimum conditions were analyzed with TGA, CHNS elemental analysis, FTIR, and GC-MS. 1,4-Dioxane showed the best performance in yielding the maximum bio-oil with 51.8% at those conditions. The higher heating values of the bio-oils ranged from 22.1 to 35 MJ/kg. Phenolic groups were the predominant components of bio-oil produced from OWP, while the intensity of alcohols, ketones, and acids varied based on used solvents. Based on energy recovery calculations, the enhancement of pristine OWP's energy efficiency depended on bio-oil yield, and quality was confirmed for all solvent types (1,4-dioxane > 1-butanol > water > ethanol).Article Citation - WoS: 17Citation - Scopus: 19Development of Ca(oh)2-Based Geopolymer for Additive Manufacturing Using Construction Wastes and Nanomaterials(Elsevier, 2023) Mortada, Youssef; Kogbara, Reginald; Masad, Eyad; Kogbara, Reginald B.; Mansoor, Bilal; Seers, Thomas; Hammoud, Ahmad; Karaki, Ayman; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyRecent growth in additive manufacturing (AM) or 3D printing in the construction field has motivated the development of various materials that vary in its composition and properties. This paper introduces, characterizes, and evaluates the performance of a sustainable and environmentally friendly geopolymer mixture composed of construction wastes. The geopolymer mixture has calcium hydroxide (Ca(OH)2) as the main alkaline activator and incorporates nanomaterials such as nano-silica and nano-clay to enhance its suitability for AM. The combined use of Ca(OH)2 for alkali activation, and nanomaterials for tailoring the behavior of construction wastes for 3D printing, is novel and addresses the shortcomings of conventional alkaline activators. The paper includes the outcomes of the analysis of the mechanical properties, printability, and microstructure of the geopolymer mixture. The 28-day compressive strength of the mixture reached 42 MPa with ambient temperature curing, which is comparable to traditional geopolymers. The inclusion of 1 wt % of nano-silica accelerated the geopolymerization process and led to the largest (35 %) reduction in the setting time. Similarly, incorporating 1 wt % of nano-clay led to reduction of the thermal conductivity from 0.709 W/mK to 0.505 W/mK, due to the introduction of thermal barriers. The printability of the studied waste-based geopolymer mixture was validated through the successful fabrication of a 3D-printed model. © 2023 The AuthorsArticle Citation - WoS: 23Citation - Scopus: 23Cold Sintering of Soda-Lime Glass(Elsevier Ltd., 2021) Karacasulu, Levent; Karacasulu, Levent; Ögür, Ezgi; Ahmetoğlu, Çekdar Vakıf; Pişkin, Cerem; Pişkin, Cerem; Vakıfahmetoğlu, Çekdar; 03.09. Department of Materials Science and Engineering; 01. Izmir Institute of Technology; 01.01. Units Affiliated to the Rectorate; 03. Faculty of EngineeringOrdinary recycled soda lime glass powder was densified via cold sintering process with the aid of concentrated NaOH solution. Increase in processing time, temperature and concentration of the NaOH solution resulted in the formation of monolithic glass artifacts with higher relative densities. The sample densified the most (95.2%) was obtained when the sintering was performed at 250˚C with a 20 min dwell time using 15 M NaOH solution.Article Citation - WoS: 16Citation - Scopus: 22Phenolic Contents, Antioxidant Activities and Potential Bioaccessibilities of Industrial Pomegranate Nectar Processing Wastes(John Wiley and Sons Inc., 2016) Sürek, Ece; Nilufer Erdil, Dilara; 01. Izmir Institute of TechnologyAntioxidant potential and bioaccessibility of co-products from industrial pasteurised pomegranate nectar (PN) processing such as peel (PP), press cake (PC) and precipitate after clarification (PAC) in comparison with raw material (arils) and final products (CON and PN) were determined. Total phenolic (TPC), flavonoid (TFC), anthocyanin (TAC), tannin contents (TTC) and antioxidant activity (TAA) were determined besides identifying major phenolics and investigating in vitro bioaccessibility after gastrointestinal (GI) digestion. PP showed the highest values, except for TAC. Phenolics (12.7-43.0%) were found to be more stable than anthocyanins (0.6-2.1%) after in vitro GI digestion. PAC was found to be a better source for anthocyanins than CON and also showed higher phenolic bioaccessibility (28.8%) than PN (19.6%). PC and PAC possessed as much TPC, TFC, TTC and TAA levels as CON, with some exceptions. Therefore, these results indicated that not only PP but also PC and PAC should be valorised as a good source for phenolics and anthocyanins.Article Citation - WoS: 22Citation - Scopus: 26Coal Fly Ash as a Potential Fixation Reagent for Radioactive Wastes(Elsevier Ltd., 2015) Lieberman, Roy Nir; Polat, Mehmet; Segev, Giora; Polat, Mehmet; Mastai, Yitzhak; Cohen, Haim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIsrael produces ∼1.3 Mt/year of fly ash (FA), a byproduct of its coal-fired power plants. Due to increasing environmental regulations, these imported coals are processed to reduce the sulfur concentration (∼0.6%). These processing methods result in a material that has an enriched alkali/alkali earth component with pozzolanic and basic properties (pH > 10.5). FAs are utilized worldwide, mainly as a cement additive for the construction industry. Recently, it was demonstrated that Class F FA can act as an excellent fixation reagent for acidic wastes from the phosphate or the oil regeneration industries. In the current work the potential utilization of Class F FAs as fixation reagents for low-activity radioactive waste from the nuclear industry was examined. Aqueous solutions containing radionuclide simulants: cesium (Cs+), strontium, (Sr2+), and cerium (Ce3+, Ce4+) were used as case studies with promising results. It is suggested that the primary fixation mechanism involves the aluminate/silicate anions at the FA surface. A novel experimental fixation approach utilizing the formation of carbonates is demonstrated and a new interaction mechanism is suggested based on the electrostatic interactions of the positively charged fine precipitates with the negatively charged FA surface. © 2015 Elsevier Ltd. All rights reserved.Article Citation - WoS: 73Citation - Scopus: 84Groundwater Contamination and Its Effect on Health in Turkey(Springer Verlag, 2011) Baba, Alper; Tayfur, Gökmen; Tayfur, Gökmen; Baba, Alper; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe sources of groundwater pollution in Turkey are identified, and pathways of contaminants to groundwater are first described. Then, the effects of groundwater quality on health in Turkey are evaluated. In general, sources of groundwater contamination fall into two main categories: natural and anthropogenic sources. Important sources of natural groundwater pollution in Turkey include geological formations, seawater intrusion, and geothermal fluid(s). The major sources of anthropogenic groundwater contamination are agricultural activities, mining waste, industrial waste, on-site septic tank systems, and pollution from imperfect well constructions. The analysis results revealed that natural contamination due to salt and gypsum are mostly found in Central and Mediterranean regions and arsenic in Aegean region. Geothermal fluids which contain fluoride poses a danger for skeleton, dental, and bone problems, especially in the areas of Denizli, Isparta, and AydIn. Discharges from surface water bodies contaminate groundwater by infiltration. Evidence of such contamination is found in Upper KIzIlIrmak basin, Gediz basin, and Büyük Melen river basin and some drinking water reservoirs in Istanbul. Additionally, seawater intrusion causes groundwater quality problems in coastal regions, especially in the Aegean coast. Industrial wastes are also polluting surface and groundwater in industrialized regions of Turkey. Deterioration of water quality as a result of fertilizers and pesticides is another major problem especially in the regions of Mediterranean, Aegean, Central Anatolia, and Marmara. Abandoned mercury mines in the western regions of Turkey, especially in Çanakkale, Izmir, Muǧla, Kütahya, and BalIkesir, cause serious groundwater quality problems. © 2011 Springer Science+Business Media B.V.