Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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2005 - 200912010 - 20133

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Department: search.filters.department.Thesis (Master)--İzmir Institute of Technology, Chemical EngineeringSubject: search.filters.subject.Nanotechnology

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Now showing 1 - 4 of 4
  • Master Thesis
    Production of Nano Calcite in Large Scale
    (Izmir Institute of Technology, 2013) Alıcı, Sezen Duygu; Özdemir, Ekrem; Özdemir, Ekrem; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Calcium carbonate (CaCO3) has been used extensively as filling material in various industries in order to improve some mechanical properties of the composite materials and to reduce the product costs. There are mainly two methods for synthesizing CaCO3 crystals: chemical method and carbonization method. The carbonization method is the most appropriate method for nano calcite production. A systematic study was conducted on the synthesis of calcite in nano sizes, homogeneous size distribution, and different morphologies by employing the newly developed small penetration method. The effects of various parameters on the particle size and morphologies such as flow rates of raw materials, concentration, pipe diameter, volumes of stabilization tank and reaction chamber, length in the reaction chamber, stirring rate, and temperature were investigated. Calcite particles of about 100-150 nm were achieved to produce in homogeneous size distributions for the developed method at large scale.
  • Master Thesis
    Production of Nano Caco3 in Bench Scale by Small Penetration Theory
    (Izmir Institute of Technology, 2013) Toprak, Görkem; Özdemir, Ekrem; Özdemir, Ekrem; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Calcium carbonate (CaCO3) has been used as filling material in various industries such as paint, paper, and polymeric materials. Using filling materials will enhance some of the physical properties of the composite material and decrease the product costs. Especially, the physical properties of the composite materials were enhanced significantly when the CaCO3 is used in nano sizes. CaCO3 can be produced from natural sources by crushing, grinding, and sieving processes, however, calcite obtained from the natural sources are usually in micron sizes and they are not in the desired quality and purity. Here, it was proposed that the dissolution rate of CO2 is the limiting step in CaCO3 crystallization and a small penetration method was developed for the limited dissolution of CO2 in the Ca(OH)2 solution. When Ca(OH)2 was added into the 10 mM CaCO3, zeta potential values of CaCO3 particles were increased from negative to positive value indicating that CaCO3 particles were stabilized in the presence of Ca(OH)2 solution. Rice-like CaCO3 particles were synthesized at the very early stage of crystallization. When crystallization progresses, the high energetic end sites started to dissolve, and the dissolution was progressed through the inside of the particles resulting in hollow calcite particles. BET surface area of hollow calcite particles was found to be 14.75 m2/g. Different parameters such as Ca(OH)2 flow rate, CO2 flow rate, Ca(OH)2 concentration, pipe diameter etc. were studied. Calcite particles in nano sizes, homogeneous size distribution, hollow shapes, and different morphologies were achieved to be produced.
  • Master Thesis
    Investigation of Shell Microstructure of Microbubbles for Diagnostic Ultrasound
    (Izmir Institute of Technology, 2013) Köse, Derya; Kılıç Özdemir, Sevgi; Kılıç Özdemir, Sevgi; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study we reported the effect of shear stress, protein adhesion, temperature, secondary interactions and gas core on microbubble stability which are the main reasons of microbubble dissolution in body. Air filled DSPC/PEG40St microbubbles were examined under shear stress. Increasing PEG40St molar ratio increased the resistivity microbubbles against shear stress. To investigate effect of emulsifier type, microbubbles were produced by mixing DSPC with DSPE-PEG1000, DSPE-PEG2000 and PEG40St at 5:5 molar ratio and PEG40St microbubbles were more stable since it provide better curvature to microbubble shell due to its shape. Shear stress experiments were also performed at different temperatures. With increasing temperature microbubbles became less stable since van der Waals interactions between shell components decreased. When microbubbles were filled with perfluorocarbon, since its solubility is lower and more hydrophobic than air, the stability of microbubbles against shear stress increased. Protein adhesion to microbubble shell was investigated by Langmuir Blodgett (LB) and Surface Plasmon Resonance techniques. Both techniques showed that, as the PEG40St molar ratio and packing density increased, protein adhesion decreased. Secondary interactions between shell components were examined via LB technique and visualized via Brewster Angle Microscopy. As third component to DSPC/PEG40St mixture, StGly, StNH2, DSPS, DSTAP was added and ternary mixtures were generally miscible. Since StGly and StNH2 has single tail, they cannot provide curvature in bubble surface. DSPS and DSTAP mixtures may be recommended drug delivery.
  • Master Thesis
    Preparation and Characterization of Metal Soap Nanofilms
    (Izmir Institute of Technology, 2005) Öztürk, Serdar; Balköse, Devrim; Balköse, Devrim; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, the production of metal (zinc and calcium) stearate nanofilms by Langmuir-Blodgett (LB) film deposition process and their structural and electrical characterizations were investigated. The interaction of stearic acid monolayer with calcium, zinc cations as functions of pH, temperature, concentration of metal cation in the subphase and barrier speed was examined in detail. The effects of transfer surface pressure, the dipping speed, drying period, pH, concentration of metal cations in the subphase and temperature in the deposition of metal stearates onto glass substrates were optimized. Metal stearate LB films were prepared and characterized by X Ray Diffraction technique. It was revealed that the zinc stearate arrangement may be identified as under the orthorhombic (R) subcell with chain tilt angle of 31o, which was confirmed by IRspectrum of zinc stearate. Atomic Force Microscopy and Scanning Electron Microscopy images showed that surface roughness on glass substrates was decreased by firstly chrome coating and then silver coating. Zinc stearate coated surfaces have large crystal size around 90 nm in agreement with XRD calculation and contained grains and defects.The results of LB film deposition processes, structural characterization of LB films and the water vapour adsorption experiments presented that ZnSt2 LB films were easily formed and have good ordered structure in comparison to CaSt2 LB films. Therefore ZnSt2 LB films were chosen to study humidity sensor characteristics. Conductivity of ZnSt2 LB films was easily affected from environmentalconditions. No hysteresis during adsorption and desorption of water vapor on conductivity-voltage measurements was observed for zinc stearate LB film.As a result, zinc stearate LB films can be used as humidity sensor. By measuring conductivity in an humid atmosphere, humidity could be determined.