Department of Chemical Engineering
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thesis.listelement.badge SYNTHESIS AND CHARACTERIZATION OF A NEW SELENOPHENE BASED ELECTROCHROMIC POLYMER(2015-01-31) KARABAY, Barış; CİHANER, AtillaA new derivative of 3,4-propylenedioxyselenophene bearing naphtyl appendages on the bridge, called 3,4-dihydro-3,3-bis ((naphthalen-1-yl)methyl)-2H selenopheno[3,4-b][1,4]dioxepine (ProDOS-Np2), was synthesized and polymerized via potentiostatic and potentiodynamic methods. Electrochemically obtained polymer film (PProDOS-Np2) is pure blue at the neutral state and highly transparent at the oxidized state. An increase in the size of the substituents on the bridge resulted in an increase in the optical contrast ratio. Upon moving from naked bridge to benzyl and to naphtyl substituents on the bridge center, the optical contrast changed from 51% to 65% and finally to 84%. When compared to polythiophene analogue, the PProDOS Np2 has lower oxidation potential and band gap, higher optical contrast ratio, coloration efficiency, robustness and stability. The polymer film preserved its properties even after thousands of cycles under ambient conditions.thesis.listelement.badge PREPARATION AND CHARACTERIZATION OF PALLADIUM-COPPER BIMETALLIC NANOPARTICLES SUPPORTED ON SILICA COATED COBALT FERRITE MAGNETIC PARTICLES FOR HYDROLYTIC DEHYDROGENATION OF AMMONIA BORANE(2015-06-25) AL-AQBI, Talaat Hikmat Hashim; KAYA, Murat; CİHANER, AtillaMetal nanoparticles have attracted much attention over the last decade due to their desired applications in catalytic systems and the usage of these particles in such systems are considered to be a promising way for bridging homogenous and heterogenous catalysis, that is to say for “quasihomogeneous” (or soluble heterogeneous) systems. Naked nanoparticles are due to high surface energy not stable and prone to coagulate while catalytic transformation is taking place. On the other hand, filtration techniques are not efficient to separate nanoparticles that have diameters of less than 100 nm. Under such circumstances, expensive ultracentrifugation is preferred to separate the product and catalyst. In order to get rid of the disadvantages of naked nanoparticles and to enhance the stability and to obtain reusable catalysts, immobilization of nanoparticles onto inorganic supports provide the desired properties for catalytic efficiency. Due to high hydrogen storage capacity (19.6 % wt) and low molecular weight, the innovations in the development of nanocomposite catalysts for the hydrolytic dehydrogenation of ammonia-borane (NH3BH3) is essential to use these catalysts as solid hydrogen carrier. In this thesis, new and reproducible catalyst system consists of palladium-copper bimetallic nanoparticles supported on silica coated magnetic particles has been prepared by wet-impregnation method. After addition of Pd2+ and Cu2+ ions on silica coated cobalt ferrite nanoparticles, nanoparticles formed by in situ reduction of the Pd2+ and Cu2+ ions with NH3BH3 on the surface of silica coated magnetic nanoparticles. The characterization of nanocomposite catalysts were done by inductively coupled plasma/optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high resolution- transmission electron microscopy (HR-TEM) and N2 adsorption–desorption technique. Palladium-Copper bimetallic nanoparticles supported on silica coated cobalt ferrite (PdCuNPs/SiO2-CoFe2O4) provide an initial turnover frequency (TOF) of 238 min-1 at room temperature that shows higher catalytic activity than both non-noble metal catalysts and noble metal based homogenous and heterogeneous catalysts that is used in the reaction of hydrolytic dehydrogenation of ammonia-borane. One of the most important opportunity of such catalyst system is that, catalysts can be collected with a magnet in the reactor wall and they are reusable for up to 5 recycles with the sustainable catalytic activity that exhibited excellent reusability of the catalyst.thesis.listelement.badge SYNTHESIS AND POLYMERIZATION OF BENZIMIDAZOLE BASED MONOMERS VIA A DONOR – ACCEPTOR APPROACH(2015-06-25) AL-OGAİDİ, Saad; CİHANER, AtillaA new series of fluorescent donor-acceptor-donor (D-A-D) type monomers based on benzimidazole acceptor unit bearing cycloalkane appendages, called 4,7-di-2,3- dihydrothieno[3,4-b][1,4]dioxin-5-ylspiro[benzimidazole-2,1'-cyclopentane] (E5E), 4,7-di-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-ylspiro[benzimidazole-2,1'- cyclohexane] (E6E) and 4,7-di-2-thienylspiro[benzimidazole-2,1'-cyclohexane] (T6T), were synthesized and polymerized via potentiostatic and potentiodynamic methods. The effect of ring size on benzimidazole unit and the kind of donor moiety in D-A-D system has been studied systematically on the electrochemical and optical properties. The optical studies showed that ring size of the benzimidazole unit has no effect on the absorbance and fluorescence properties, whereas the oxidation potential of E5E, E6E and T6T monomers varied with respect to both the ring size and donor unit: 0.89 V, 0.83 V and 1.22 V vs Ag/AgCl, respectively. All polymers have ambipolar (p- and n-type doping) and electrochromic properties. While the polymer films PE5E and PE6E are green at neutral state and transparent at oxidized state, the polymer PT6T has no appreciable color change between its neutral and oxidized state. The polymers bearing 3,4-ethylenedioxythiophene unit as donor units (PE5E and PE6E) exhibited lower band gap values (1.21 eV and 1.18 eV, respectively) than PT6T (1.53 eV). When compared to PT6T, PE5E and PE6E polymers are more stable under ambient condition. While PE5E retained 76% of its electroactivity after 4000 cycles, PE6E has 65% of its electroactivity after 2000 cycles.thesis.listelement.badge PREPARATION AND CHARACTERIZATION OF SILVER-PESeE FILM DEPOSITED ON ITO GLASS SURFACE AS A SURFACE ENHANCED RAMAN SCATTERING SUBSTRATE(2015-06-25) ALSHUWAİLİ, Kadhim Taresh Raisan; KAYA, Murat; CİHANER, AtillaSurface enhanced Raman scattering (SERS) is known as a very attractive technique for the characterization and detection of a variety of chemical and biological molecules due to their impressive characteristics such as giving spectral fingerprint of vibrations, high sensitivity and insensitivity to water. One of the most important points of the SERS technique is the requirement for producing a substrate having an ideal surface morphology to facilitate the achievement of the most favorable enhancement. Here a novel, simple, reliable, and reproducible one-step electrochemical method for the preparation of surface enhanced Raman-active polymer-mediated silver nanoparticles (Ag NPs) on planar indium tin oxide (ITO) coated glass substrates was reported. Poly (4,7-di-2,3-dihydrothieno [3,4-b] [1,4] dioxin-5-yl-2,1,3 benzoselena diazole) (PESeE) film was used as a support material for dispersing silver nanostructures on the surface homogeneously. The morphologies of the prepared substrates have been investigated by field emission scanning electron microscopy (FE-SEM). The effect of the thickness of PESeE polymer film and the amount of silver particles on the polymer film on the SERS response were studied as well as repeatability and stability of prepared substrates. Brilliant cresyl blue (BCB) has been used as Raman probes to evaluate the properties of the new SERS substrates.thesis.listelement.badge SYNTHESIS AND CHARACTERIZATION OF NEW POLYMERIC MATERIALS FROM ELEMENTAL SULFUR(2015-06-26) SALMAN, Mohamed Khalifa; CİHANER, AtillaNew elemental sulfur based polymeric materials called poly(sulfur-random divinylbenzene) (poly(S-r-DVB)) were synthesized by ring opening polymerization in the presence of a mixture of o-, m- and p-diviniylbenzene (DVB) as a crosslinker. In order to get the copolymers, the elemental sulfur was melted at 160 oC and therefore ring-opening polymerization of the S8 was promoted and a clear yellow/orange colored liquid was obtained. Then, various amounts of DVB were added to this liquid directly via a syringe and continued to further mixing at 200 oC for 10 minutes to get viscous reddish brown polymeric materials. The copolymers are soluble in common solvents like tetrahydrofuran, dichloromethane and chloroform, and they can be coated on any surface as thin film. The characterization of the materials were performed by using nuclear magnetic resonance, fourier transform infrared and Raman spectroscopies. The morphological properties were monitored via scanning electron microscope technique. Thermal analysis showed that an increase in the amount of DVB in the copolymers resulted in an increase in the termal decomposition temperature. On the other hand, poly(S-r-DVB) copolymers exhibited good percent transmittance as 50 %T between 1500 and 13000 nm in electromagnetic radiation spectrum, which make them good candidates to be amenable use in military and surveillance cameras.thesis.listelement.badge SYNTHESIS AND CHARACTERIZATION OF NEW DITHIENOSILOLE BASED CHROMIC POLYMERS(2015-06-27) AL-JUMAILI, MOHAMMED; CİHANER, Atilla2-Ethylhexyl substituted dithienosilole based soluble polymers including thiophene (P1) and bithiophene (P2) units were synthesized via Stille Coupling reaction. The polymers were characterized by using nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA) techniques. The presence of 2- ethylhexyl substituents on the silole ring gave solubility property to the polymers in common solvents. According to GPC measurements, weight average molecular weights of the polymers P1 and P2 were found to be as 70977 with a polydispersity index (PDI) of 2.30 and 110439 with a PDI of 1.42, respectively. Fluorescent polymers in toluene solution have maximum emisssion bands at 634 nm for P1 and 613 for P2. Chemical and electrochemical doping of the polymers in solution and film forms were monitored by using ultraviolet-visible (Uv-vis) spectroscopic technique. The polymers exhibited chromic (chemochromic and electrochromic) properties. While the colors of the neutral polymer films are purple for P1 and reddish brown for P2, both polymers are transparent sky blue at their oxidized states. The band gaps of polymers in film forms were calculated as 1.81 eV for P1 and 1.92 eV for P2. Also, electrochromic device applications of the polymers were done. Electrochemical and optical behaviors of the polymer demonstrated that they can be good candidates for optoelectronic applications.thesis.listelement.badge THE EFFECT OF PHELLINUS TORULOSUS MUSHROOM EXTRACT ON ANTIOXIDANT ENZYMES(2017-01-07) ALSAMRRAEY, Maiser Zaid; İŞGÖR, S. BelginIn order to prevent free radical damages there has been an increasing interest in finding natural sources which can play as antioxidant. Even though several studies were done on mushrooms, Phellinus torulosus was not examined in details. In this study, the free radical scavenging capacity of the total phenolic and flavonoid contents of Phellinus torulosus mushroom extract was evaluated by DPPH and the antioxidant property was tested by catalase (CAT), superoxide dismutase (SOD) and glutathione- S-transferase (GST). In this study, four different mushroom extracts have been prepared using cold water, hot water, methanol, and ethanol. As ethanol extract resulted in the highest contents of total phenolic and flavonoid (as 625.125 µg/ml and 463.5 µg/ml respectively), the ethanol extract was used in the following steps for determining the radical scavenging capacity and antioxidant property of the mushroom. The free radical scavenging capacity of Phellinus torulosus ethanol extract was examined by using DPPH free radical. In this experiment by using quercetin and gallic acid as standards, DPPH radical scavenging capacity of mushroom extract was observed and IC50 value was calculated as 0.04353 g/l. The antioxidant property of Phellinus torulosus ethanol extract was determined by observing its effect on GST. The result showed that the mushroom extract inhibited the activities of GST about 60%. The effect of ethanol extract of Phellinus torulosus on GST was shown with IC50 calculated in the range of 0.1609 to 0.9076 g/l. Again in the same experiment Phellinus torulosus ethanol extract was found to have no effect on CAT and SOD enzymes with less than 15% inhibition for both enzymes.thesis.listelement.badge DESIGN, SYNTHESIS AND DNA BINDING ABILITY OF NOVEL PLATINUM(II) COMPLEXES CONTAINING BIDENTATE NITROGEN AND SULPHUR DONOR LIGAND(2017-01-07) ABDUSALAM, MOHAMED; ÖZALP YAMAN, ŞenizOne of the main challenges in bioinorganic chemistry is to synthesize new DNA targeting complexes as a potential anticancer drug leads providing better efficiency with low tissue resistance compared to cisplatin. For this purpose, three novel platinum(II) complexes containing 5,6-di-2-thienyl-2,3-dihydropyrazine in asymmetric- (asy-), cis and bis- geometry have been synthesized, identified and their DNA binding ability has been studied by spectroscopic techniques and gel electrophoresis. Spectroscopic data and the calculated binding constant values were demonstrated that the synthesized drugs bind DNA in different types. While Cis and Asy complexes perform base binding covalently, bis complex interact with DNA by intercalating mode but in weaker extend. Gel electrophoresis results were in agreement with the spectroscopic findings. All the complexes induce an oxidative single strand cleavage in the presence of a reductant (ascorbic acid) on the double helix structure of DNA with the decreasing activity order from Asy to Bis. On the other hand, cytotoxicity experiments carried out at the neutral conditions, suggested that the Bis complex is the most promising anticancer agent for the treatment of Human Glioblastoma.thesis.listelement.badge DNA INTERACTION AND CYTOTOXICITY OF THE PLATINUM BLUE COMPLEX CONTAINING 2-AMINOTHIOPHENOL(2017-01-07) SALEM, SAFIA; ÖZALP YAMAN, ŞenizSince the discovery of cisplatin, metal based agents have gained significant interest of researchers as potential anticancer drugs. Several drugs have been rationally synthesized to overcome the hurdles of cisplatin, majorly its toxicity and resistance. Search for less toxic, but still potent anti-cancer platinum compounds revealed a class of platinum complexes with pyrimidines called platinum-pyrimidine complexes also known as “platinum blue” (Pt-blue) complexes. Here, we describe DNA binding ability of the Pt-blue complex [Pt4(2-atp)8(H2O)(OH)] (2-atp: 2- aminothiophenol). In order to investigate the nature of the interaction between the Pt-blue complex and DNA, spectroscopic measurements were made and the results of UV titration, thermal behavior, viscosity and fluorometric titration of the Pt-blue treated DNA were evaluated. Our results suggested that the compound was able to partially intercalate DNA that related to the anticancer activities of the drugs.thesis.listelement.badge THE EFFECT OF FOMITOPSIS PINCOLA MUSHROOM EXTRACT ON ANTIOXIDANT ENZYME ACTIVITES(2017-01-07) ELMUBARK, Marwa; İŞGÖR, S. BelginA long time ago, mushrooms and their extracts had been widely used for medicinal and food purposes. Nutritionally, mushrooms are low in energy and fat but high in protein, carbohydrate and dietary fiber. Mushrooms are also an important source of biologically active compounds with potential medicinal value. Bioactive secondary metabolites found in mushrooms include phenolic compounds, sterols and triterpenes. In different studies with mushrooms and isolated bioactive constituents have many pharmacological effects such as anti-tumors, antioxidant, antiviral, hypocholesterolemia and hypoglycemic effects. Using of mushroom or mushroom products in our daily diet may provide health benefits. In this study, Fomitopsis pinicola mushroom extracted with seven different methods, by using three different solvents; water, methanol, and ethanol. Total phenol and flavonoid contents of all this extracts were determined to evaluate their antioxidant potency that can act as secondary defense in the biological system, beside the primary defense enzyme systems, such as catalase (CAT), superoxide dismutase, and glutathione-S- transferase. Also the effect of this mushroom on DPPH (1,1-Diphenyl-2- picrylhydrazyl) radical scavenging activity was examined. Since hot water boiled for one hour, and repeated for two times extracts has highest total phenolic contents (TPC) and total flavonoid contents (TFC) valves; 658.900 µg of GAE/ml of extract, and 245.800 µg of QE /ml of extract respectively. DPPH and all enzyme assays were continued by using this extract. This extract has ability to stabilize free radical DPPH about 70%, with IC50 value of 0.272 g/L. also this extract inhibits CAT enzyme activity as 50%, and on the other hand GST enzyme activity was inhibited by the same extract as 85%. The IC50 values of CAT and GST for this extract were calculated as 1.951×10-5 g/L, and 0.086-0.593g/L respectively. While this extract has not significant effect on SOD enzyme and IC50 value calculated as 0.001 g/L.thesis.listelement.badge INVESTIGATION OF THE PHOTOCATALYTIC ACTIVITY OF PALLADIUM NANOPARTICLES ADDED PEDOT(2017-01-07) AHMED, Matira Miud Alaribi; KAYA, MuratInvestigation and development of efficient and low-cost method for wastewater treatment to effectively eliminate the pollutants is so important for environmental remediation. Among the wastewater treatment methods, advanced oxidation processes (AOP’s) consists of the usage of homogenous and heterogeneous photocatalysts, known as the most effective way. The development of photocatalytic materials used in AOP’s is so important. The advancement of photocatalysts which sensitive to solar light would allow more effective utilization of solar light brings sustainable ways to various environmental problems. Recently conductive polymers noted as a new types of effective photocatalytic materials under solar light. Poly(3,4-ethylenedioxythiophene) (PEDOT) considered as one of the most important candidate among the conjugated polymers. In this thesis, photocatalytic activity of the palladium added PEDOT (PdNPs/PEDOT) polymer was investigated. In this study, a facile production procedure was demonstrated to fabricate the PdNPs/PEDOT as a photocatalyst. The phtocatalytic activity of PdNPs/PEDOT nanocomposite material was checked into the decolorization of MB under UV and solar light exposure. The photocatalytic behavior of bare PEDOT, TiO2 nanoparticles and PdNPs/TiO2 nanostructure were also investigated in order to make comparison with PdNPs/PEDOT nanostructure. The characterization of nanocomposite catalysts were done by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM) energy dispersive X-Ray (EDX) coupled with SEM and Raman Spectroscopy.thesis.listelement.badge PREPARATION AND CHARACTERIZATION OF POLYCARBONATE/GLASS FIBER –MICA HYBRID COMPOSITES(2017-02-07) ALHAJ, Ibrahim Alsadig Mohammedkhair; TİRKEŞ, SehaThe improvement of physical properties of polycarbonate is still great interest of scientists due to the huge application areas. In this study polycarbonate matrix was reinforced with glass fiber (GF), mica (MC) and in hybrid form. The preparation of composites was carried out using co-rotating twin screw micro-compounder at 280 oC and the test samples were prepared by laboratory scale injection-molding device. The percent compositions of added fillers for PC/GF and PC/MC composites were 5%, 10%, 20%, and 30%. The total percentage of both filler was kept as 30% for hybrid composites (MC%/GF%) of which comspositions were 5/25, 10/20, 20/10, 25/5, respectively. The characterizations of obtained composites were examined via tensile test, impact test, melt flow index test, differential scanning calorimetry analysis and scanning electron microscopy methods. The obtained results showed that the best values of tensile strength were obtained for the lowest mica concentration and 20% glass fiber containing composites gave the optimum value. The concentration increment of the additives more than these values caused agglomerations and reduction of homogeneous distribution of them in the PC matrix, which were revealed by scanning electron microscopy.thesis.listelement.badge PREPARATION AND CHARACTERIZATION OF THERMOPLASTIC POLYURETHANE NANOCOMPOSITES AND THEIR HYBRID COMPOSITES(2017-03-04) Mohamed, Salma A. Taher; TİRKEŞ, SehaThe improvement of physical properties of thermoplastic polyurethane (TPU) is still great interest of scientists due to the possible wide application areas. In this study, polyurethane matrix was reinforced with polyhedral oligomeric silsesquioxane (POSS), halloysites nanotubes (HNT) and in hybrid form. The preparation of composites were carried out using co-rotating twin-screw micro-compounder at 210 oC and the test samples were prepared by laboratory scale injection-molding device. The weight percentages compositions of added fillers for TPU/POSS and TPU/HNT nanocomposites were 0.5%, 1.0%, 1.5%, and 2.0% respectively. As for TPU/POSS HNT hybrid composites the weight percentages were (0.5%, 0.5%), (1.0%, 1.0%), (0.5%, 1.5%), (1.5%, 0.5%) respectively. The characterizations of obtained composites were examined via tensile test, impact test, melt flow index test, hardness test, dynamic mechanical analysis and scanning electron microscopy methods. The obtained results showed that the best value of tensile strength was obtained for the lowest HNT content of 0.5%. For the impact test, the maximum impact strength was achieved when the POSS value was 0.5%. POSS nanoparticles are homogeneously dispersed in TPU matrix for the lowest loading (0.5%). Further additions of POSS cause formation of agglomerations. HNT and POSS nanoparticles seem to be well mixed in micro image of TPU/ 0.5% POSS 0.5%HNT hybrid composites. Homogeneity of their mixing in TPU matrix decreases as the concentrations of POSS and HNT increase, which were revealed by scanning electron microscopy.thesis.listelement.badge MODELING AND SIMULATION OF A VACUUM DISTILLATION UNIT IN AN OIL REFINERY(2017-05-02) Almuamri, Ali; Kayı, HakanIn this thesis, we studied the modeling and simulation of a vacuum distillation unit (VDU). A distillation unit operating under vacuum pressure was designed to be fully used in Libyan refineries to make benefit from its residue instead of exporting it to other countries, and to extract more valuable products. The atmospheric residue has a very high boiling point (370 ºC). We need to find a way to decrease its boiling point, and then to separate it into its components easily and efficiently. It is known that when the pressure applied on a fluid decreases its boiling point decreases too. In the vacuum distillation column, the boiling point of the atmospheric residue is decreased by decreasing the pressure applied on the residue. The main products from the vacuum distillation unit are off gas, light vacuum gas oil (LVGO) and heavy vacuum gas oil (HVGO). In addition, a vacuum residue is produced. To be able to investigate the further distillation of the residue of the atmospheric distillation, a vacuum distillation unit was designed and simulated by Honeywell UniSim® Design v450 software, which is a very powerful program that helps us to create steady-state and dynamic models for plant design. At the end of the simulations, the liquid volume percent of the atmospheric residue was found to be 31.9%, while the liquid volume percent of vacuum residue was found to be 0.098%. Our simulations by using UniSim software indicated that the use of VDU significantly decrease the amount of the residue in the petroleum refinery.thesis.listelement.badge THEORETICAL INVESTIGATION OF CARBONYL SULFIDE CAPTURE BY AQUEOUS DIETHANOLAMINE SOLUTION(2017-05-02) Hadia, Abubaker; Kayı, HakanCarbonyl sulfide (COS), an unwanted impurity, released with a variety of processing gases. Capturing of COS can be achieved with liquid absorbents. Two different mechanisms are proposed in the literature for COS and diethanolamine (DEA) reaction, and both drive to a formation of thiocarbamate. The first mechanism is zwitterion intermediate mechanism, which takes two reaction steps. The first step is the forming of the zwitterion, and the second one is the deprotonation of the formed zwitterion. The second mechanism is termolecular mechanism in which a complex forms as intermediate in a single step reaction. Four different termolecular reactions among COS, DEA and water were investigated through the quantum chemical calculations, and structural, energetic and thermochemical properties were revealed. Theoretical standard free energy of activation (∆ ‡G ° ) and reaction (∆G°rxn), equilibrium constant (Keq) and reaction rate constant (k) values for these four termolecular reactions were calculated. Density Functional Theory (DFT) was applied during the theoretical investigations of this study utilizing the B3LYP hybrid functional, and 6-311G(d) basis set. In conclusion, calculated activation energy and reaction rate constant values obtained in this study were compared with the experimental data available in the literature, and under the guidance of these findings, the most probable termolecular reaction mechanism for the COS capture by aqueous DEA solution was revealed.thesis.listelement.badge INVESTIGATIONS OF FLAX FIBER AND BASALT FIBER CONTAINING POLY(LACTIC ACID) HYBRID ECO-COMPOSITES(2017-05-02) Eselini, Najah Hashmi N.; TİRKEŞ, Seha; TAYFUN, ÜmitIn this study, poly(lactic acid) (PLA) was reinforced with flax fiber (FF) and basalt fiber (BF) as both individually and together hybrid forms. BF and FF containing PLA eco-composites were prepared using twin-screw micro-compounder at the total constant mixing ratio of 30 wt%. Test specimens were shaped by lab-scale injection- molding. Mechanical properties, thermo-mechanical characteristics, flow behaviors and morphological properties of composites were investigated by tensile, Shore hardness, impact tests, dynamic mechanical analysis (DMA), melt flow index (MFI) test and scanning electron microscopy technique (SEM), respectively. Mechanical test results show that tensile strength, percentage strain, elastic modulus and impact strength are extend up to higher values with increase in BF content in hybrid composites. On the contrary, presence of FF displays negative effect in which these values drop down drastically as the FF concentration increases. On the other hand, slightly higher hardness values are obtained by the addition of FF at higher loadings. DMA analysis reveals that BF inclusion leads glass transition temperature of PLA to one point higher but hybrid and FF containing composites shift that temperature to lower values. Similarly with mechanical test results, storage modulus of composites enhance with increase in BF concentration and remarkable decreases are observed for FF filled composites. MFI results display that additions of FF and BF individually cause fourfold and twofold increase for MFI value of PLA. Hybrid composites exhibit average MFI values between PLA/FF and PLA/BF composites. According to SEM analysis, basalt fibers disperse more homogeneously in PLA matrix as compared with flax fibers.thesis.listelement.badge DESIGN AND OPTIMIZATION OF AN ATMOSPHERIC DISTILLATION UNIT IN AN OIL REFINERY(2017-05-02) SOWANI, KHALED; Kayı, Hakan; Alper, ErdoğanToday, production and distillation of crude oil are important processes in almost all around the world. Price of the petroleum products is rising due to the high demand which is much stronger than expected. In the last few years, simulation of the different processes has become an important tool, especially in the study of behavior of almost all the chemical processes. A proper simulation can bring the best advantages to industry, such as improving the in knowledge about the processes without the need to carry out the real operation of the processes. Simply, simulation can translate the mathematics of a computer modeling to description of the system behavior based on the data of input parameters. Simulation and modeling are very important in different engineering applications, because they describe the process operation that may not be feasible, may be inaccessible, too costly, or dangerous. In this study a computer model of atmospheric distillation unit (which is also called crude distillation unit, CDU) in Libyan oil refinery was designed and simulations were performed to improve the middle distillate productions in CDU focusing on Naphtha product. Data of the crude oil, the operating conditions of the process unit, and other essential data were collected from actual refinery and entered into the simulation environment to generate the CDU model. Aspen program provides a capability to design the entire process accurately and gives us accurate information of how processes take place. This study includes the design and simulation of the crude distillation unit, and aims to improve its middle distillate productions, by concentrating on the improvement of the volumetric flow rate of the naphtha product, because it’s one of the most demanded valuable products. According to our findings, it’s possible to increase mainly the production of naphtha, kerosene (jet fuel), light gas oil (LGO). In addition reducing the residue volumetric flow rate at the same time is possible, and this is one of the objectives of this study. Ultimately, the simulation of the CDU is successfully completed, and the obtained results are discussed. The effects of the different operation conditions in the crude oil refining process on the yield and the composition of the crude oil products are investigated. To ensure the simulation works successful, the obtained results are compared with the actual distillation column production data.thesis.listelement.badge PREPARATION OF COPPER NANOPARTICLES ADDED POLYTHIOPHENE FOR DEHYDROGENATION OF AMMONIA BORANE(2017-06-02) ALABLAQ, Salha M.; KAYA, MuratNanocatalyst is the material with an increased catalytic activity due to their high surface-to-volume ratio. In the case of homogeneous nanocatalysis like colloidal metal nanoparticle suspensions, they are found in the same phase with precursors used for reaction and products. The main advantage of this type of catalyst can be considered as highly selective systems compared with heterogeneous ones. But low thermal stability, serious metal contamination and difficulty recovery of the catalyst are the main disadvantages of homogeneous catalyst. In order to overcome these problems, heterogeneous type nanocatalysts are widely used in reactions. In this type of catalyst, metal nanoparticles are immobilized onto support materials like silica, alumina, and carbon based materials. Nowadays, some polymer support gained great interest due to their facile and cheap methods to produce them. Hydrogen energy is considered as one of the most important clean source. For this reason a lot of studies are performed to produce hydrogen storage materials like metal hydrides, chemical hydrides, organic molecules, metal organic frameworks and carbon nanotubes. Between these storage materials chemical hydrides has attracted great attention due to their high hydrogen storage capacity. Among the chemical hydrides, ammonia borane (AB) gained great importance because of high hydrogen content (19.6 wt %), low toxicity and high stability. With the usage of appropriate catalyst it is possible to get three moles of hydrogen per mole of AB under mild conditions. For this reason, it is so important to produce a catalyst with high-efficiency and improved kinetic parameters in the hydrolysis of AB under mild conditions for hydrogen energy applications. In this thesis, a facile way for preparing copper nanoparticle (CuNPs) supported on polythiophene as catalyst for hydrogen production from aqueous AB was presented. For this, initially polythiophene polymer support material was prepared. After that Cu (II) ions were added onto polymer support by utilizing wet impregnation method. Then copper ions were reduced by using sodium borohydride and copper nanoparticles were obtained. The catalytic activity of prepared nanocatalyst was revealed. An initial turnover frequency (TOF) value is founded as 11.8 min-1 . The stability and reuse capacity of the prepared catalyst were also investigated. The prepared catalyst shows good stability and reuse capacity. CuNPs added onto polythiophene shows nearly same activity after 5th reuse in the hydrolytic dehydrogenation of AB.thesis.listelement.badge THE ISOLATION AND ANALYSIS OF THE MEDICINAL POTENTIAL OF METHANOLIC EXTRACT OF THE STACHYS CRETICA L. FLOWERS(2017-06-02) LATRESH, MALIKA KHALIFA; İşgör, BelginAntioxidants are vital substances which possess the ability to protect the body from damage caused by free radicals. A variety of antioxidants exits within the body and many of them are derived from dietary sources as fruits, vegetables and plants. The plants are utilized in folkloric medicine to treat many diseases. In this study, plant flowers was extracted with methanol and its total phenolic content (TPC) was measured as 25.32 mgGAE/g of extract and total flavonoid content (TFC) was measured as 29.60 mgQE/g of extract. This study utilized chromatography and was applied to separate extracts in to six fractions. The fraction utilized in enzyme assays was due to its high TFC as72.78 mgQE/g . The Glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD) activities were measured by using multi-mode plate reader (Spectra MaxM2). The inhibitory effects of plant on Glutathione-S-Transferase enzyme (GST) activity was about 80% with IC50 value of 0.6001 g/L, on SOD it was about 100 % with IC50 value of 0.2909g/L. The effect of Stachys Cretica on Catalase inhibition 75% with IC50 of 0.03741g/L.thesis.listelement.badge PREPARATION AND CHARACTERIZATION OF PALLADIUM NANOPARTICLES ADDED POLYTHIOPHENE FOR HYDROGEN PRODUCTION FROM AMMONIA BORANE(2017-06-02) ALJARAI, Sumaia Ahmed Muftah; KAYA, MuratNowadays, nanostructured catalysts gain great attention due to their high catalytic activities in various types of reactions. For this reason more efforts have been devoted to develop more efficient ways to produce catalysts with desired sizes. To prepare an effective nanocatalyst, one of the main parameter is to prepare proper support materials. It keeps the activity constant by preventing nanoparticles from agglomeration and increases the reuse performance by giving easy isolation properties. Among the support materials, polymers can be considered as good candidates due to their cheap and easy preparation ways and stabilites. Hydrogen energy is considered as one of the most promising green energy resources. Therefore, the design and production of proper catalysts, which can be used in the production of hydrogen from the storage materials is so important. Among the solid hydrogen storage materials like metal hydrides, chemical hydrides, organic molecules, metal organic frameworks and carbon nanotubes, ammonia borane (AB) considered as one of the most effective hydrogen storage material. The hydrogen content of AB is 19.6 wt % and it is nontoxic and stable under air and water. With the usage of suitable and effective catalyst, it is possible to take all hydrogen from AB at moderate conditions. For this reason, production of highly efficient catalysts to enhance the catalytic parameters in the production of hydrogen from AB is of great importance for the development of hydrogen energy and its extensive usage. In this thesis, to produce catalyst for hydrogen generation from aqueous AB under mild condition a novel support material, polythiophene, was used to immobilize the palladium nanoparticles by using a wet impregnation method. The prepared catalyst shows good catalytic activity at 25 °C. An initial turnover frequency (TOF) value is calculated as 28.9 min-1 . Furthermore, PdNPs, which are loaded on polythiophene support, show high stability and reuse property.