Doktora Tezleri

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Adsorption of reformer off-gas on NaX zeolite and metal organic framework (mil53(AI)): Equilibria and kinetics
(Izmir Institute of Technology, 2013) Güneş Yerkesikli, Alev; Çakicioğlu Özkan, Seher Fehime
Synthetic gas produced from steam methane reforming (SMR off -gas) is a mixture of H2, CO, CO2, and CH4 can be used in fuel cell after purification. In this study adsorption as a purification tool was used to obtain high H2 content of gas mixture from SMR off gas. Zeolites and metal organic framework were used as an adsorbent. CO2 equilibrium studies on K rich NaX zeolites, prepared with ultrasonic and traditional methods, and metal organic framework MIL53 (Al) shows high adsorption on zeolites than MIL53(Al) up to 1 atm. K rich zeolites give lower adsorption than NaX zeolite. Adsorption isotherms obtained for MIL53 (Al) is linear ( favorable for zeolites). This makes MIL53(Al) is an promising adsorbent for high pressure application. Adsorption equilibrium at 5 atm shows that NaX zeolite is good adsorbent for the SMR off gas with the following orders: CO2>CH4>CO> H2. Kinetics of SMR off gas in MIL 53 (Al) were studied by using Zero Length Column (ZLC) method. The results show that the calculated diffusivities are strongly dependent on temperature but weakly dependent on purge flow rate. The study reveals that transport is controlled by intracrystalline diffusion. The activation energy on diffusion are nearly same (about 41 kJ/mol) and not change with respect to kinetic diameter of SMR off gases. Heat of SMR off gas adsorption on MIL53(Al) obtained from Henry’s constant shows that adsorption is exothermic. The study shows that the ZLC method is an effective tool to investigate the diffusion kinetics of SMR off-gas gases in MIL53(Al).
Adsorptive characteristics of aflatoxin B1 in the presence of purified clinoptilolite rich mineral and lactobacillus plantarum S2
(Izmir Institute of Technology, 2012) Bulut Albayrak, Çisem; Ülkü, Semra
The human diet contains a wide variety of natural carcinogens. Aflatoxin B1 (afB1) is the most toxic and most prevalent compound. Both probiotic lactic acid bacteria and clinoptilolite rich zeolite mineral have potential to eliminate this toxin. This study was planned in order to investigate adsorptive characteristics of afB1 by local purified clinoptilolite rich mineral (PNZ) and probiotic strains which were isolated from different natural sources (fermented cabbage, boza ) in the present work. PNZ and isolated strains were characterized by using several physical, chemical and biological techniques. Adsorption characteristics of both probiotic lactobacilli and PNZ were investigated in simulated gastrointestinal solutions. The chosen probiotic strain was identified as L. plantarum .The studies indicated that, both L. plantarum S2 and PNZ can eliminate afB1 in the phosphate buffer solution. They are more effective when they were used together (45% for L. plantarum S2, 32% for PNZ, 86%for L. plantarum S2 and PNZ together). AfB1 adsorption equilibrium data were best represented by Sips isotherm model for PNZ, whereas by Langmuir isotherm model for L. plantarum S2. Thermodynamic studies implied that afB1 adsorption by mineral and L. plantarum S2 was physical adsorption. Experiments with different temperatures showed that afB1 adsorption by PNZ was exothermic but afB1 adsorption by lactobacilli was endothermic. Adsorption kinetics were analysed by diffusional models and reaction models for afB1 adsorption by PNZ mineral. Both film diffusion and /or intra particle diffusion were effective on adsorption kinetics depending on the experimental conditions (Temperature, pH, agitation speed, etc).
Advertising media and housing production: Gated communities of İstanbul in the post-2000s
(Izmir Institute of Technology, 2009) Kan Ülkü, Gözde; Erten, Erdem
In this dissertation I investigate how the marketing strategies of the developing consumer society has infiltrated the marketing of high end housing in Istanbul as a corollary development of globalization. I aim to analyze marketing strategies as active agents that shape the design of these newly emerging housing developments based on the theme of .an ideal life style. through advertising media in the form of TV commercials, newspaper ads, publicity brochures etc.This study also focuses on the representation and dissemination of this elusive .ideal. to the public via the advertising campaigns of these housing settlements. Therefore the cases that the study is based on concentrates on the Turkish architectural scene after 1990 when consumer culture.s most significant impacts on architectural products are observed. The study observes that the marketing of this new type of suburbanization in Turkey is concomitant with the rise of a new middle class that has a high purchasing power. Therefore I analyse the life style characteristics of architectural projects that provide for this class, according to Bourdieu.s conceptualization of life styles, and aim to uncover how this conceptualization reflects on the marketing of high-end housing.In this regard, the concept of .distinction. will be used as key theoretical tool to analyse the qualities of environments proposed in the selected cases. The relation between the advertising strategies of a .distinct life style. and its legitimization process which directly affect the .fabrication. of these specialized housing settlements will remain at the core of my thesis problem.
Aerodynamic optimization of a transonic aero-engine fan module
(Izmir Institute of Technology, 2016-07) Kor, Orçun; Özkol, Ünver
Aerodynamic design of an aero-engine fan blade is a multi-step process with multi-variables. The general purpose in aerodynamic design is to obtain proper blade angles and flowpath geometry providing the necessary pressure ratio with maximum efficiency, while respecting the structural and aerodynamic constraints. The throughflow design in aerodynamic design procedure is a key step where one can obtain a basic aero-design which generally fixes 80% to 90% of the final fan geometry, by adjusting parameters like blade exit angle distribution, solidity, hub and shroud contour, meridional chord length, etc. Throughout this procedure, the aim of the designer is to obtain an optimum (i.e. light, reliable and robust) system with highest efficiency. Among optimization methods, zero order methods are reported to fit best for turbomachinery problems, due to their good performance in discrete and non-differentiable problems and their ability to find the global optimum. Genetic algorithm is the most widely used optimization method in turbomachinery optimization. Methods inspired by swarm intelligence are reported as promising global optimizers, whereas, to the author’s knowledge, there are no reported studies that employs such algorithms in turbomachinery throughflow optimization. These methods can find the neighborhood that provides the globally optimum design, rather than exactly finding the global design. This drawback is overcome by hybridizing genetic/swarm inspired algorithms by first order (gradient based) methods. Within this aspect, the present study focuses on developing genetic and swarm inspired algorithms hybridized with gradient based algorithms to find the optimum throughflow design of a transonic aero-engine fan module.
Against style: Re-reading "new architecture" in early republican period in Turkey (1931-1940)
(Izmir Institute of Technology, 2011) Dündar, Bilgen; Yücel, Şebnem
This dissertation is intended as a contribution to the understanding of modernization in the early Republican period (ERP) architecture, namely including the neglected attitudes. It criticizes the stylistic periodizations such as "National Style" and "International Style" and rigid classifications such as classifications of Sedad Hakkı Eldem only as the forerunner of national architecture and Seyfi Arkan only as the forerunner of the international architecture in Turkey. This study aims to transcend these reified categories by presenting the varieties and contradictory approaches that existed in architectural theory and practice. This dissertation aims to develop a new reading of the ERP architecture by questioning the categories that were constructed by the first generation of architectural historians who produced their texts between 1973 and 1983. The main aim of this dissertation is to show simultaneous existence of different modernities in the ERP architecture. By revealing different understandings of new architecture in architectural theory, architectural pedagogy and architectural practice, this dissertation focuses on the heterogeneity of the architectural milieu. The first generation of architectural historians constructed the ERP architecture with Euro-centric set of theories, and with conventions such as categorizations and stylistic periodizations. They also read that periodʼs architecture within the frame of the nation-building process. In their texts, the architecture followed a linear and progressive modernization process, paralleling the nation-building process. By tracing the different understandings of modern architecture in architectural theory and tracing different tendencies of architects in architectural practice, this dissertation aims to question not only the categorizations and stylistic periodizations, but also this linear and progressive modernization ideal.
An agent based model for exploring the effects of overconfidence on the winner's curse in construction projects
(01. Izmir Institute of Technology, 2022-12) Aldemir, Bora; Kale, Serdar
As a result of errors in cost estimation, the winning companies in competitive environments such as bids, auctions, etc. fail to achieve the anticipated profit or even incur losses. This phenomenon is labelled as the “winner’s curse.” Diverse causes led to the occurrence of this circumstance. Until recently, technical errors were thought to cause most construction estimation errors. Behavioral economics has shown that certain biases in individual decision-making can also contribute to these undesirable situations. Overconfidence is common. This illusion is when a person thinks they are better at making decisions than they really are. The agent-based modeling method was used to examine this bias. This method investigates the system pattern created by heterogeneous individuals with independent macro-level behavior. In this study, individuals can be considered as construction companies. The prevalent pattern in the sector is the phenomenon of the winner's curse. However, focusing solely on the overconfidence effect may not yield meaningful results. Risk aversion is regarded as a protective behavior against the negative effects of the overconfidence. There may also be a correlation between the number of bidders and the winner's curse. This study demonstrates that the phenomenon of the winner's curse exists in all dimensions of the overconfidence effect. When the number of bidders is small, overconfidence behavior has little impact on the winner's curse, but when the number of bidders is medium or large, the winner's curse increases slightly as the overconfidence effect decreases. Risk aversion does not provide any protection against the winner's curse phenomenon.
Agro Food System transitions? Exploring alternative Agro Food Initiatives in Izmir, Turkey
(Izmir Institute of Technology, 2016-07) Karakaya, Emel; Özatağan, Güldem
This dissertation investigates emerging Alternative Agro Food Systems (AAFSs) in Turkey and does so by focusing on three niche initiatives in İzmir. Building on Regime Theory and the Multi-Level Perspective, it views these initiatives as strategic niches and explores their development processes by documenting their socio-technical practices. Thus, this thesis fulfills the understanding of newly emerging alternatives and their transformation in Turkey with regard to their development processes in İzmir. Through exploratory qualitative multiple case study, this dissertation provided a meso-level investigation, documentation of the agro food system and micro-level investigation of Alternative Agro Food Initiatives in Turkey. A micro-level exploration is undertaken by three niche initiatives in İzmir; (a) producer initiated Alternative Agro Food Niche- Gödence Cooperative, (b) consumer initiated Alternative Agro Food Niche- BİTOT and (c) producer-consumer collaborated Alternative Agro Food Niche-Foça Earth Market. Case studies, which are explored in İzmir, have provided a city-level investigation through examination of role of İzmir in the emergence and development of alternative agro food niches. Case studies reveal characteristics and development processes of alternative food initiatives. Gödence revealed a niche that shows a degree of compatibility with the incumbent regime. This compatibility blunted the innovative capacity of the niche due to several structural reasons and path-dependencies. Stabilizing path-dependencies created tendencies which restrain the diffusion of socio-technical practices. On the other hand, BİTOT and Foça Earth Market formed new niches. The creativity, talent to widen voluntarism and existing networks of Buğday Association provides BİTOT a web of volunteers to create, design and apply socio-technical practices. Foça Earth Market’s unique innovation capacity is lying under its artifice to use incumbent regime institutions to create alternative socio-technical practices. The flexibility in the Foça Niche to motivate actors including those from mainstream regime has contributed to the innovative capacity of the initiative.
An analiytical approach to semi-private and semi-public spaces within the context of urban housing pattern
(Izmir Institute of Technology, 2002) Özgen, Elif Yeşim; Eyüce, Özen
This study aims at understanding the changing public private relations in housing environments designed and produced after 80.s as a consequence of redefined context of 20th century life style and housing models. The study also aims to examine and display the transactions of the modernization processes in Turkey. Especially the mass housing settlements, in İzmir are chosen as study areas. The study evaluates the quantitative and qualitative properties of the settlement areas in which masss produced housing units are used repeatedly and monotonously.The .garden city. and .satellite city., which are accepted as the 20th century modern settlement models are surveyed, and their spatial transformations are analyzed. In this framework, the reflections of urban spatial transformation in Europe and Turkey are evaluated whitin the context of city of Izmir. Especially, the presence of semi-private areas, which hold the opportunity, and the spatial potentials of socialization such as gathering, collecting, intersecting, confronting, are surveyed within five different mass housing site examples in Izmir. From the .private space., which is the basic .housing unit. to . public space., levels of the spatial hierarcy, (which is the subject of social psychology), meant to be put forward. The transition spaces, which are semi- private and semi-public, are argued as to whether they constitute criteria in contemporary design applications. Such a concern is evaluated by comparative analysis. The study suggests to create a qualitative contribution for futher designs of quantitatively designed mass housing environments.Key words: modern settlement models, housing spatial transformation, housing pattern/hiyerarchy (public, semi-public, semi-private and public spaces), privacy concept in housing, spatial quality.
Analysis and application of linearization technique for nonlinear problems
(Izmir Institute of Technology, 2020-12) İmamoğlu Karabaş, Neslişah; Tanoğlu, Gamze; Izmir Institute of Technology
The purpose of this thesis is to investigate the implementation of linearization technique combining with the multiquadric radial basis function method to nonlinear problems which appears in engineering and physics. Presented linearization technique is formed by the Frechet derivatives and Newton Raphson method. This technique is applied to Burgers' equation, Coupled Burgers' equation and 2-D cubic nonlinear Schrödinger equation. From the numerical results of the problems, it is believed that this technique can be used to solve other nonlinear and system of nonlinear partial differential equations numerically.
Analysis and synthesis of parallel manipulators
(Izmir Institute of Technology, 2008) Can, Fatih Cemal; Alizade, Rasim
In this study, novel parallel manipulators are introduced for industrial and medical applications. New methods are developed for the structural synthesis of Euclidean platform robot-manipulators with variable general constraints (EPRM). New mechanical structures such as serial, parallel and serial-parallel EPRM are designed along with proposed method.A new dimensional synthesis method of two DoF planar and spherical seven link mechanisms is presented. Interpolation and least square approximations are used to design the mechanism. In the solution of dimensional synthesis problems, nonlinear equations are converted to system of linear equations. The motion generation problem of a 3 DoF platform robot manipulator is solved for three, four and five precision poses. It is shown that the synthesis problem can be solved analytically for three prescribed poses. However, the solution is achieved by using a numerical method for four and five poses. The result, which is obtained from three prescribed poses, is used as an initial guess for four and five poses. Kinematic analysis of the manipulators is investigated. After the derivation of vector-loop equations, inverse and direct position analyses of the manipulators are presented. Constant orientation workspace of a three DoF spatial parallel manipulator is presented. The mechanical elements which are necessary for the construction of manipulators are introduced. The information about the motors which is needed for actuation of manipulators is given. Three DoF parallel manipulator is constructed for a industrial packaging system. Assembly of manufactured parts and mechanical elements are shown.
Analysis of the electromagnetic scattering from flat plates by using different sinc-type basis fuctions in method of moments
(Izmir Institute of Technology, 2012) Özbakış, Başak; Kuştepeli, Alp
Electromagnetic scattering from three dimensional arbitrary flat surfaces illuminated by a plane wave is investigated by using sinc-type basis functions in the method of moments (MoM) in this study. Sinc-sinc based Galerkin MoM formulation is obtained and its fortran program is developed firstly. The number of integrals to be computed is decreased by using analytical properties of the sinc function in the formulation. Therefore, the CPU time for obtaining the coefficient matrix is decreased appreciably. The relative error during the generation of the main matrix elements is obtained between 0.058% and 0.095% for considerably large matrices. Rooftop based MoM formulation is developed and it is coded with a similar approach used in sinc based program. The accuracy and CPU time of the sinc based bistatic scattering results are compared with those of rooftop. The MoM formulation of the sinc-pulse (sinctop) basis functions with non-Galerkin case is developed to reduce the overflow problem at the edges. Induced surface currents and far-field results of the sinc-sinc and sinc-pulse based formulations are compared with those of the rooftop basis functions and with the ones obtained from SuperNEC. Both sinc-sinc and sinc-pulse based simulation results are in good agreement with the results of rooftop based and SuperNEC simulation results. The main purpose in this study is to obtain accurate bistatic scattering results by using different sinc-type basis functions in MoM procedure while filling the main matrix in less CPU time when compared with the well-known methods.
Analysis of the interaction between theory and practice in urban planning: Understanding Izmir experience
(Izmir Institute of Technology, 2002) Kaya, Nursen; Özdemir, Semahat
Urban planning, as one of the factors in shaping the urban structure, aims to help to increase the quality of life both through making the necessary spatial arrangements and through development of the urban policies. However the interventions brought through this field of study and action have always been under discussion in terms of the or success of this intervention. Accordingly one of the most ongoing discussions in planning literature covers the issues related to the theory and practice interaction with the aim to see the accordance or disaccordance between planned action and the real world of action and to help to clarify the need or success of this intervention. This thesis study is carried out with the aim to understand the interaction between theory and practice in urban planning. It aims to analyze whether the theory of planning guides to the practice of planning and whether the practice of planning shapes the urban structure. In other words it attempts to clarify the role of theory on practice of planning and the impacts of planning practice on urban structure. This study is formed of two main parts as the theoretical frame and the case study. In the first part the study presented the framework of planning theory and a short review of major theoretical approaches stated in planning literature. In the second part the study presented planning experiences of the city of İzmir through carrying out an analysis of planning practices in terms of theoretical background and implementation of planning decisions. The research method followed for carrying out of the study is mainly based on literature search, İzmir Metropolitan Municipality archives search, Yeni Asır newspaper search and on-site observations. This study found out that planning practices of İzmir had been generally guided by various theoretical approaches and these practices had performed many impacts on urban structure of İzmir. However it can not be claimed that the practice had been successfully guided by the theory or the practice had been successful to shape urban structure. Keywords: Planning Theory, Planning Practice, Theoretical Approaches, Planning in Turkey, Planning in İzmir, Urban Structure of İzmir, Prost, Danger, Le Corbusier, Aru, Bodmer.
Analysis of walkability measurement tools (WMTs)
(Izmir Institute of Technology, 2019-06) Paykoç, Eda; Akış, Tonguç
Walking is the most basic act of human which makes all equal and liberates them in the built environment. For defining how walking friendly the area is, walkability is an issue started to be discussed from its several different aspects. Although walkability is studied from several different disciplines, it has neither accurate definition nor definite criteria.Starting from 1990s, walkability has started to be measured with hard-copy walkability measurement tools (WMTs) and followed by web-based walkability measurement tools. In the literature, WMTs are generally used as a tool to measure the walkability level of the selected case. However, there are few studies which tries to understand and examine the background process of these WMTs.The aim of this thesis is to categorize and define the background idea of walkability measurement tools by criticizing their keystones and their main ideas. The mapping, clustering, tabling and analyzing processes are the main devices to develop critical analysis. In tabulation, two specific charts are composed: Comprehensive Data Chart and Content Analysis Chart. Under Comprehensive Data Chart, properties of WMT are defined and categorized. In Content Analysis Chart, each tool’s content of WMTs are compared and criticized. Finally, the thesis developed a critical analysis for defining, comparing and understanding each and every single WMT.
An analytical study of the design potentials in kinetic architecture
(Izmir Institute of Technology, 2004) Korkmaz, Koray; Arkon, Cemal
This dissertation is concerned with the potentials of kinetic structures in architecture; what they are, what they can do for us, and how we can go about designing them. Ultimately, it aims at proving the applicability of kinematic methods in the design process of the adaptable space organizations by carrying out a personal design process of a novel kinetic structure. The course of this dissertation explores the ways in which kinematic synthesis methods contribute to the design processes of kinetic structures and adaptable spaces, which we call kinetic architecture.The idea of motion is not new. However, the concept of motion and its practical reflection appear more in end-products because of the dynamic, flexible, and constantly changing activities and developments in building technology. As a result of the rapid change in activities of modern society and developments in building technology, a need of the adaptable space emerged which was the necessary precondition for the rise of the concept of motion in architecture. This conceptual transformation may be dated to the end of the twentieth century. What marks the approach to the design of this new, late twentieth-century conception of space is 'motion', which will now play an increasingly important role both conceptually and in applications of design. Our capability of utilizing kinetics in architecture today can be extended far beyond what has previously been possible. The present dissertation describes kinematic analysis and synthesis methods used so far in mechanical engineering and explores its direct or in-direct applications into the architectural field.Arguing that the potential of kinetics in architecture remains far from fulfilled, it offers concrete direction and method for innovation. Focusing on responsive spatial adaptability and kinetic structures, it develops a foundation for the application of kinetic structures as a means of enhancing the performance of space. The motivation lies in creating adaptable spaces. There is a need for adaptable spaces and a design method for achieving this by building kinetic structures that can physically convert themselves through kinetics to adapt to the ever-changing requirements and conditions. This thesis proposes the use of kinematic methods in the design process of kinetic structures to create adaptable space organizations. In order to show the applicability of kinematic methods in the design process of the adaptable space organizations, a new type of an architectural umbrella covered by flexible material is developed for covering open-air spaces. Graphical synthesis method is used in the design process and the performance of the architectural umbrella is analyzed with Visual Nastran 4D. This is a CAD program capable of kinematic analysis.
Antimicrobial, antioxidant properties and chemical composition of some spices/herbs
(Izmir Institute of Technology, 2013-12) Yavuzdurmaz, Hatice; Baysal, Ayşe Handan
The present study aims to investigate the chemical composition, antimicrobial activity, and mechanism of antimicrobial activity, antioxidant properties of essential oils and extracts and the effects of them when applied to minced beef samples. For this purposes; four essential oils (bay leaf, thyme, clove and cumin), two extracts (grape seed and olive leaf) and constituents of essential oils (eucalyptol, linalool, α-terpineol and α-pinene) were subjected to related tests. Chemical characterization was complemented for all essential oils and extracts. Antimicrobial activity was examined against Staphylococcus aureus, Escherichia coli O157:H7, Salmonella Typhimurium, Listeria innocua, Shewanella putrefaciens, Carnobacterium divergens and Serratia liquefaciens. All tested compounds were effective on the bacteria with different concentrations. Antioxidant activity was proved by FRAP and DPPH methods. Physical disturbance and changes in the structures of bacteria was demonstrated by various techniques. The activity of two most potent essential oils (thyme and clove) was investigated in the minced meat application study. The findings represented that clove essential oil restricted the growth of S. Typhimurium and coliform bacteria. They did not have a significant inhibition effect on the aerobic mesophilic bacteria, total yeasts and molds and also psychrotrophic organisms. The results indicated that L* and a* values were maintained during the storage period. The featured effect of essential oils was antioxidant characteristic in meat application study. All treatment showed significant reduction in oxidation comparing with control. The obtained results may suggest that tested essential oils possess compounds with antimicrobial characteristic as well as antioxidant activity and therefore they can be used as natural preservatives in food especially in meat products.
Application of exergy analysis method to energy efficient building block design
(Izmir Institute of Technology, 2014-03) Mert, Yelda; Saygın, Nicel
This dissertation introduces the exergy analysis method into urban planning field in order to find out the amount of energy that can be conserved in a building block when energy efficient design is applied. Two hypotheses are developed here: 1. Exergy analysis is a suitable tool for the built environment, and 2. Energy efficient design parameters provide energy saving in the built environment. A case study approach is undertaken in order to test the hypotheses stated above. To do this, first, the energy efficient design parameters have been derived from the literature and design alternatives are developed accordingly; second, data has been gathered from the case area for the exergy calculations; third, exergy analysis of existing building blocks and proposed design alternatives are carried out, and finally, the amount of decrease in the exergy loss due to energy efficient design is found out. The findings in this study show that the exergy efficiency of the existing building blocks is nearly 2 %, while the proposed design alternatives are nearly 10-11 %. The overall exergy loads of the alternative plans are found as 166.3W, 225.1W, 142.5W, 137.8W and 184.8W respectively for winter and 105.4W, 140.0W, 89.9W, 86.3W and 125.3W respectively for summer on a housing unit basis. These results are much better when compared to the existing situation per housing unit which is 1079W (winter) and 1173W (summer). The best alternative energy efficient planning and design brings 1631 W (winter) and 2810W (summer) of exergy saving that corresponds to 799 TL/year and 978 kg/year reduction in CO2 greenhouse gases emission per housing unit. This data shows that the expected results and are in harmony with the literature. As a result, the suitability and importance of the exergy analysis on the built environment is proved by revealing the energy conservation and sustainable use of energy through using energy efficient design parameters.
Applications of electrospun nanofibers in filtration processe
(Izmir Institute of Technology, 2013) Horzum Polat, Nesrin; Elçi, Latif
Electrospinning is a simple and versatile method to fabricate ultrathin fibrous mats from a wide variety of organic and/or inorganic materials. Since it allows fabricating fiber diameter and surface/internal structures by solution and instrumental parameters, electrospun fibers provide much enhanced functionalities, which can not be obtained by bulk materials. This thesis examines the filtration, sensing and catalytical applications associated with the remarkable features of electrospun nanofibers. The systems studied are reported herein; (i) The first part of this dissertation deals with the filtration applications of electrospun nanofibrous membranes.  Nano-sized chitosan fibers were utilized for sorption of Fe(III), Cu(II), Ag(I), and Cd(II) ions from aqueous solutions.  The surface of chitosan fibers were further functionalized by monodisperse nano zero-valent iron (nZVI) particles for the removal of inorganic arsenic species.  Sorption of radioactive U(VI) ions from aqueous systems via column sorption under continuous flow was performed using amidoximated polyacrylonitrile fibers. (ii) The second part of this dissertation presents sensing applications of ceramic fibers.  Humidity sensing properties of electrospun ZnO fiber mats were investigated by quartz crystal microbalance (QCM) method and electrical measurements.  Electrospinning technique was used as coating process for deposition of CeO2/ZnO and ZnO based nanofibers on the electrode of QCM. The fiber-coated QCM sensors were used for the detection of volatile organic compounds (VOCs). (iii) The last part of this dissertation describes an approach to fabricate hierarchically structured composite nanofibers. The nanostructured materials prepared by the simultaneous electrospinning of CeO2 and LiCoO2 precursors and SiO2 nanoparticles were used for the photocatalytic degradation of Rhodamine B.
Applications of mid-IR spectroscopy for identification of wine and olive yeasts and characterization of antimicrobial activities of phenolics on yeasts
(Izmir Institute of Technology, 2015-12) Canal, Canan; Özen, Fatma Banu; Baysal, Ayşe Handan
The aim of this study was application of mid-IR spectroscopy in combination with multivariate statistical analysis for characterization of yeasts from two fermented products, wine and olive, in comparison with cultural and molecular tests and characterization of antimicrobial effects induced by olive phenolics on yeasts. Totally 19 wine yeasts were molecularly identified as M. pulcherrima (11%), P. membranifaciens (16%), H. uvarum (5%) and S. cerevisiae (68%). According to FTIR spectroscopic data of wine samples, S. cerevisiae isolates formed a cluster which were generally separated from all other yeasts. Totally 182 olive yeasts were identified from naturally debittered Hurma and a common olive variety and their leaves. The most common yeasts were Metschnikowia sp. (39%) and Aureobasidium sp (78%) in the first and the second harvest years, respectively. Since only Aureobasidium sp. was the common yeast isolated from Hurma during both years, any link between natural debittering of Hurma and the yeast population of this olive type might be related to Aureobasidium sp. Molecularly identified yeast types generally formed different clusters and showed spectral differences. For antimicrobial activity tests, all phenolic compounds were found effective on both S. cerevisiae and A. pullulans; however, A. pullulans was observed to be more sensitive. Antimicrobial activity was differentiated with respect to treatment time and phenol concentration with statistical treatment of FTIR data. As a complementary technique, FTIR could be successfully used for identification of yeasts and characterization of antimicrobial activity of phenolics against yeasts.
Architectural characteristics and construction techniques of domes in a group of Ottoman baths
(Izmir Institute of Technology, 2011) Reyhan, Kader; İpekoğlu, Başak
In Ottoman bath architecture, domes adjoined in varied numbers and sizes are structural element ensuring dynamic superstructure adjustment exterior and fascinating spatial features involving the interior lighting elements. The examination of cause-effect relationship in the original architectural and constructional characteristics of domes, the main elements of dynamic superstructure adjustment, is significant in terms of pointing out the retention features of construction details. In addition, informed knowledge for the purpose of contributing to conservation works of the baths is necessary to focus on in this dissertation. The aim of the dissertation is to identify the original morphological characteristics, construction techniques and use of materials and to investigate the relationship between architectural and constructional characteristics that involve span, height, thickness, bond types, the number and rows of oculi, the type of transition elements and the height of transition element and the exterior supporting elements of the dome. In this context, the domes of the studied baths were examined in term of construction techniques in superstructure integrality with their supporting elements. In this content; the original morphological characteristics, construction techniques and the use of materials on the Ottoman domes with their supporting elements, transition elements and frame of the domes from outside were examined by the use of conventional method through field survey and were studied in the framework of cause-effect relationships. In addition, statistical analysis methods were used and evaluated in order to examine the relationships between architectural and constructional characteristics of domes. This dissertation is significant in terms of contributing to cover a lack of knowledge in construction systems of domes and transition elements of the public baths for the purpose of constitution of systematic knowledge in leading protection and conservation decisions.
Architectural design characteristics of protective structures at archaeological sites and their impact on conservation of remains
(Izmir Institute of Technology, 2013-07) Yaka Çetin, Necmiye Funda; İpekoğlu, Başak
Protective structures are built to provide long term protection for the immovable cultural heritage against the possible damage that may arise from environmental conditions such as rain, wind and sun as well as the activities of the living like vegetation and uninvited animals. Most of the protective structures have been found to be inadequate to fulfill this purpose and conservation problems were observed on the remains under those structures. The inadequacies are mostly related to the architectural design of the protective structures. The aim of this study is to identify the architectural characteristics which have an impact on protective efficiency and how they are related to the deterioration factors. With this scope, sixteen protective structures that were selected from Turkey and abroad were analyzed through site surveys and literature studies. In order to identify and assess the role of protective structures on creating deterioration factors, this study groups the design characteristics under typology, structural system, roof system, roof material, façade system, façade material, thermal control system and drainage system and the deterioration factors under sources of water, instability of microclimate and the activities of the living. The relationship between these groups were analyzed and evaluated. As a result, the type of the protective structure as a shelter or an enclosure, selection of the design elements such as roof and façade systems as well as the materials, proper application of thermal control systems and drainage systems are the main characteristics of the design that determine the efficiency of the protective structures. The study will make important contributions to the theoretical and practical aspects of the design process of protective structures.

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