Phd Degree / Doktora

Permanent URI for this collectionhttps://hdl.handle.net/11147/2869

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Now showing 1 - 10 of 23
  • Doctoral Thesis
    A Strategy for Disaster Risk Management Regarding Deliberate Destruction of Historic Urban Sites: Antakya, Turkiye
    (01. Izmir Institute of Technology, 2023) Mamaklı, Fatma Sezgi; Turan, Mine
    The protection process of cultural heritage before, during, and after a possible deliberate destruction is not well defined in the Turkish legal system. This study aims to present a deliberate destruction risk management plan (DRMP) for historic urban sites considering all phases of deliberate destruction risk with an emphasis on before destruction phase. Suggesting the content of the future work for during and after destruction phases and simulating the proposed before destruction measures for the historic urban site around Uzun Çarşı Street and Habib-i Neccar Mosque in Antakya are among the objectives. DRMP was proposed for historic urban sites by defining the techniques of risk management: assessment, reduction, mapping, and implementation. Risk factors for traditional streets and heritage buildings in a historic urban site were determined with reference to numerical and categorical data of physical properties, heritage values, and managerial characteristics. Risk parameters were determined as hazard and exposure, vulnerability, and coping capacity which were calculated with risk factors. Risk assessment and risk reduction implementation and mapping were prepared as a guideline by the collaboration of information coming from the site survey and literature review. The preparedness of historic urban sites against deliberate destructions was increased by the risk reduction strategies of DRMP. Results obtained by implementation of risk assessment strategies of DRMP to the case study area showed that the southeast of the case study area has high risk level. The implementation of risk reduction strategies created a dramatic decrease of risk level from high to low for most of the traditional streets and heritage buildings.
  • Doctoral Thesis
    Investigations of Indoor Thermal and Air Flow Conditions in a Tobacco Warehouse
    (01. Izmir Institute of Technology, 2023) Gerçek, Mümine; Başaran, Tahsin
    This study investigates the thermal performance and indoor environment conditions of naturally and hybrid ventilated industrial buildings. Numerical analyses and experimental measurements were conducted in a tobacco warehouse in İzmir, Turkey. Parametric analyses were performed with three different approaches: i) 15 architectural design strategies are evaluated by using a sensitivity analysis. It is found that roof insulation thickness, shading projection factor, and shading angle have significant impact on heating and cooling requirements. In addition, the most influential factors on operational CO2 emissions are thickness of insulation material and conductivity of thermal insulation material. ii) Vertical and volumetric temperature gradients, crucial for stored product quality, are assessed through field measurements and CFD simulations. Ceiling-mounted radiant cooling systems reduced indoor temperatures by 3°C, while floor heating systems increased temperatures by 7°C, ensuring a consistent range of 21- 25°C by providing a range at defined indoor temperature values. Maximum loads are determined as 12.9W/m2 for cooling and 39.6W/m2 for heating. iii) The air change effectivenesses of different ventilation conditions are analysed. Four additional fans improved air exchange quality and decreased the volumetric mean age of air (AoA) from 1230 to 525 seconds. It is indicated that, while additional fans may decrease the mean AoA, maximizing the fan operation capacities is not obligatory to achieve increased air change effectiveness. Besides, the analysis of various fan operation scenarios significantly improves indoor environment conditions and energy efficiency. This thesis emphasizes the importance of design parameters in influencing indoor environmental conditions and energy consumption. The investigation of thermal air mixing and conditioning strategies underscores the need for a combined experimental and numerical approach. The findings contribute to effective solutions for warehouses storing temperature-sensitive products, ensuring optimal storage conditions and mitigating temperature variations during logistics operations.
  • Doctoral Thesis
    Development of a Telemedicine Platform for Remote Monitoring of Patients
    (01. Izmir Institute of Technology, 2023) Tarım, Ergün Alperay; Tekin, Hüseyin Cumhur; Mevsim, Vildan
    Telemedicine supports patients and healthcare professionals to provide remote medical services and to ensure that medical operations, services, and applications. Telemedicine provides mobile health services, doctor-patient communication, relationship and consultation, medical clinic, and operation service for the diagnosis, monitoring, treatment, and rehabilitation by remote health services. In this thesis, telemedicine-based applications and integrated devices are developed to assist in the diagnosis, monitoring, and treatment processes of specific diseases. In this regard, a WebRTC-based telemedicine application has been developed to ensure the transfer of health data and doctor-patient communication for monitoring diseases. The developed telemedicine application performance of providing doctor-patient communication and its effect on the management of chronic heart failure disease were examined. Thereupon, medical diagnosis and wearable devices have been developed that can be integrated into the telemedicine application that has been proven for disease monitoring. As part of this study, vital health data, biomarkers, and pathogen analysis were performed by developed devices to diagnose and monitor three chronic diseases, namely sleep apnea, chronic kidney disease, and COVID-19. First, a wearable device platform has been developed that can analyze breathing patterns via diaphragm acceleration and breath temperature and diagnose and monitor sleep apnea. Afterward, electromechanical LOC platforms used for colorimetric determination of serum creatinine levels for the diagnosis of chronic kidney disease by two methods were characterized and presented in detail. Finally, a real-time LAMP-based electromechanical device used to detect SARS-CoV-2 viral RNA has been produced, and a colorimetric rapid test system has been developed and tested for COVID-19 diagnosis. In this way, devices and systems integrated into the telemedicine platform have been developed for use in different diseases and medical applications. With these developed platforms, disease diagnosis, treatment and rehabilitation, remote monitoring and patient management are provided with inexpensive, portable, user-friendly, easy-to-use solutions without the need for professional service providers.
  • Doctoral Thesis
    Production of Pectin From Wastes and Low-Grade Products of Sun-Dried Fig Processing: Optimization of Pectin Extraction and Characterization of Its Major Properties
    (01. Izmir Institute of Technology, 2023) Çavdaroğlu, Elif; Yemenicioğlu, Ahmet
    This thesis aimed extraction and characterization of pectin from processing wastes as stalks and low-grade fruits of sun-dried figs as an alternative pectin source. The extraction performed with three techniques (hot acidic, ultrasonic, enzymatic extraction) was optimized for key parameters. The hot acidic extraction, the most feasible method, yielded 11.7% crude fig stalk pectin (CSP) and 9.4% crude low-grade fig pectin (CFP) at optimal extraction conditions. The CSP had higher galacturonic acid content (GA: 34.2%) and degree of esterification (DE: 45%) than CFP (GA: 32.2% and DE: 36.7%). Purification of CSP gave pectin (PSP) with the highest GA (63%) and DE (65.9%). Despite differences in sugar compositions (D-glucose, L-rhamnose, D-galactose and L-arabinose), fig and citrus pectins displayed similar molecular weights and FT-IR profiles. The fig pectins were characterized for their gelation, antioxidant activity, water/oil absorption, emulsification/foaming capacities and stabilities, and viscosity. The properties of edible fig pectin films obtained with or without CaCl2 crosslinking were also investigated. PSP films showed greater mechanical strength (15.6-19.1 MPa), but lower water vapor permeability (6.28-12.85 g.mm/m2.day.kPa) than other films. The crosslinked CFP film exhibited the lowest solubility (32.8%) and degree of swelling. The emulsion films of CFP with eugenol (EUG) characterized and applied as a coating on whole melons effectively inhibited Listeria innocua (-2.2 log reduction) within 1 weeks at 10 °C. Fig pectins exhibited comparable or superior functional properties than commercial pectins, thus, utilization of low-quality figs and fig stalks into pectin could provide huge economic benefits to Turkish dried-fruit industry.
  • Doctoral Thesis
    Development and Characterization of Novel Bioink by Using Decellularized Extracellular Matrix for Bone Tissue Engineering Applications
    (01. Izmir Institute of Technology, 2023) Kara Özenler, Aylin; Tıhmınlıoğlu, Funda; Havıtçıoğlu, Hasan
    Bone tissue engineering has focused on the development of functional scaffolds that can organize bone regeneration with appropriate structures and properties. Three-dimensional (3D) printing technology enables the development of personalized scaffolds. In addition, biological scaffolds obtained by decellularization have various advantages for developing natural-based scaffolds. The development of printable, patient-specific bioinks derived from decellularized extracellular matrix could provide 3D fabrication of tissues and organs with high potential to mimic native tissues. The presented thesis study demonstrates the development of various bioink compositions for bone tissue engineering applications. In this regard, bone tissues were decellularized with a novel method and then characterized in order to verify the removal of whole cellular components for eliminating immunological reactions. After the pulverization of tissues, decellularized bone (DB) particles were used as an additive within various ink combinations (alginate-, gelatin- and alginate-gelatin-based). Thus, various bioink formulations were developed containing DB particles, biopolymers and mesenchymal stem cells (MSC). All prepared bioinks were bioprinted, then the viability, proliferation and differentiation capacity of the cells inside the structures as well as the physical, rheological, and printability properties of the inks were assessed. The results revealed that all bioink combinations were suitable for bioprinting and the addition of DB particles improved cell proliferation and osteogenic differentiation in all bioink formulations. Alginate-based bioinks exhibited the greatest printability and shape fidelity, gelatin-based bioinks showed the highest cell proliferation and attachment, also, gelatin incorporation into alginate-based bioinks improved the biological activity of cells. In conclusion, cytocompatible, functional composite bioinks developed in this thesis study are of value for bone tissue engineering research in future to explore their functions in the living system and show complete bone regeneration while maintaining their stability for a long time.
  • Doctoral Thesis
    Development of New Chemometrics Approaches To Determine Physical and Chemical Properties of Crude Distillation Unit Products Based on Molecular Spectroscopy
    (01. Izmir Institute of Technology, 2022) Meşe Sezen, Ayten Ekin; Özdemir, Durmuş
    Crude distillation units are the first processing units of crude oils based on fractional distillation. The properties of the petroleum products obtained from refinery units are frequently analyzed to ensure that the off-spec product cannot be obtained and that the process is working under the desired conditions. This study aims to develop a method based on multivariate data analysis to determine physical and chemical properties of petroleum samples as an alternative to time-consuming and conventional analytical methods. Four different petroleum products obtained from CDU for years were selected and used in this study, which are heavy and light diesel, heavy and light straight run naphtha. Four different spectroscopic methods which are UV-Vis, Fluorescence, FT-NIR and FTIR-ATR spectroscopy, were performed and compared. Multivariate calibration models were developed using Partial least Squares (PLS) and Genetic Inverse Least Squares (GILS) algorithms. For heavy and light diesel, predictive performance of three different spectroscopic methods were compared and for heavy diesel UV-Vis spectroscopy, for light diesel FT-NIR spectroscopy was selected for most of the parameters. Developed models by fluorescence analysis of light diesel samples conducted with two different measurement modes and synchronized fluorescence spectral data has resulted in better models compared to total fluorescence spectra. Studies with straight run naphtha samples were obtained from three different refineries and prediction performances were compared. All obtained model results indicates that developed methodology can be used in routine operations instead of conventional analytical methods.
  • Doctoral Thesis
    Photonic Crystal Textiles
    (Izmir Institute of Technology, 2022) Çetin, Zebih; Sözüer, Hüseyin Sami
    Photonic crystals are man-made structures that can be used to manipulate the flow of light. They are classified as one-, two- and three-dimensional photonic crystals according to the periodic variation of the dielectric profile in space. Apart from artificial photonic crystals there are numerous examples of naturally occurring photonic crystals which have evolved mostly for structural coloration, such as wings of butterflies, natural opal gem stone, peacock feathers to name a few. Using photonic crystal structures the propagation of electromagnetic waves can entirely be prohibited by means of photonic band gap. Considering the fact that approximately two thirds of the heat loss of the human body occurs through electromagnetic radiation with a wavelength around 10 microns, it becomes important to consider photonic crystals for the purpose of reducing heat loss in textiles. We observe that the textile, by virtue of the fact that it has been produced by weaving, already has a periodic structure, and thus is a potential candidate for a photonic crystal. With the right fiber that the textile is woven and the right weave pattern, the textile itself would be a photonic crystal. The most common weave patterns used in the textile industry are plain weave, basket weave, dutch weave and twill weave. In this thesis, we used the finite-difference time-domain method to search for the optimum weave pattern to minimize heat loss by the human body.
  • Doctoral Thesis
    Determination of Vitamin D by Sensor Technologies Based on Molecular Imprinted Polymers
    (Izmir Institute of Technology, 2022) Ölçer, Yekta Arya; Eroğlu, Ahmet Emin; Demir, Mustafa Muammer
    Vitamin D is an essential nutrient in the body; it plays important roles in human health. Both its lack and excess can have health risks. As a consequence, there is a great demand for development of simple and precise detection methods for vitamin D derivatives in different samples. Molecular imprinting polymers (MIPs) are artificial receptors that can recognize target molecules in solution. In this study, two different polymerization techniques were used to obtain MIP/NIP sorbents/films for the detection of vitamin D3. Firstly, molecular imprinted solid phase extraction (MISPE) method was proposed prior to HPLC-DAD analysis. Optimized parameters were as follows; sorbent amount of 5.0 mg for 5.0 mL of 1.0 mg/L vitamin D3 in 90:10 (v/v) ratio of H2O:MeOH solution, 5 hours sorption time and MeOH:HOAc ratio of 90:10 (v/v) as desorption solution. The accuracy of the method was verified with spike recovery test for PBS:MeOH in a ratio of 90:10 (v/v) and overall recovery was found as 85.1 (±4.3, n=3). In latter case, a quartz crystal microbalance (QCM) method was proposed for determination of vitamin D3. Electrochemical polymerization of poly(4-vinylpyridine) MIP/NIP films were achieved on gold working electrode by cyclic voltammetry (CV). Mass-transfer ability of the polymer films were analyzed by electrochemical impedance spectroscopy (EIS). The electrochemical QCM (eQCM) was used to develop thin polymer films on quartz crystals and vitamin D3 determination was achieved by QCM. In a preliminary test, as small a concentration as 0.0100 mg/L vitamin D was detected with the QCM method.
  • Doctoral Thesis
    Conservation proposals for Göbekli Tepe enclosures
    (Izmir Institute of Technology, 2022) Çelik, Keziban; İpekoğlu, Başak
    The conservation of archaeological sites is of great importance as they provide physical remains of past civilizations. Göbekli Tepe, which is one of the most important archaeological site in human history was included in the World Heritage List in 2018. Remains in Göbekli Tepe archaeological site are enclosures surrounded by circular or rectangular wall rows, and containing monolithic T-shaped pillars in the center and peripheral walls in two layers. The aim of this study is to examine the construction technique and relations between structural elements and to define conservation problems in order to develop conservation proposals. The method of the study is the evaluation of the data collected during the field survey together with the information given in the literature. In order to determine the similarities and differences between the layers, components and alignment characteristics of enclosures were defined, the relations between these components were examined. It was found that there is relationship between the diameter of enclosure and height of central pillar, and this ratio was same in two enclosures and close in another enclosure. The state of conservation and preservation conditions of the structural elements of the enclosures were examined and risk classes were determined. The problems observed in the structural elements were determined as crack, deformation, fracture, material loss, disintegration. It had been suggested to stabilize the walls to prevent further damage, to design and develop the support system for the pillars, and to carry out regular monitoring to detect possible damage or problems for components.
  • Doctoral Thesis
    Production and Characterization of Porous Ceramics for High Temperature Applications
    (Izmir Institute of Technology, 2022) Semerci, Tuğçe; Ahmetoğlu, Çekdar Vakıf; Akdoğan, Yaşar
    This thesis focuses on the production and characterization of different porous polymer derived ceramic (PDC) components (foams, additively manufactured (AM) honeycombs, and aerogels) and demonstrates their potential for high temperature applications, including gas permeability (up to ~700 o C), molten metal filtration, and heat exchanger. The foams were produced via the replica technique and different pore sizes, ranging from 300 μm to 2 mm, silicon oxycarbide (SiOC) ceramic foams were able to be formed. The average total porosity of the foams was 96 vol% with a specific surface area (SSA) of ~80 m2 /g. AM-made honeycomb-like cellular structures with different cell sizes (578 μm, 1040 μm) were obtained via fused filament fabrication. Finally, SiOC aerogels were synthesized using siloxane resin, then dried at ambient pressure and room temperature. The produced SiOC aerogels showed a total porosity of around 80 vol% and an SSA reaching 250 m2 /g. Regarding the high temperature applications of porous PDC components, initially, the gas permeability of SiOC foams was tested, and the results showed stability up to 700 °C in the air without any loss of functionality, offering reusability even in aggressive environments. In the subsequent studies, filtration of molten aluminum alloy was tested using various porous components. PDC foams demonstrated better performance in comparison to the AM-made cellular structures and commercial SiC foams. Finally, heat exchange analysis was performed to evaluate the heat transfer of SiOC foams, and an increase in pressure drop was found to be directly proportional to the rate of increase in air velocity.