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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Application Of Isokinetic Sampling Technique For Local Solid Densities In Upward Liquid-solid Flows Through An Annulus

Camci, Gulden 01 September 2003 (has links) (PDF)
In this study, radial solid density distributions in upward flowing water-feldspar mixtures through a concentric annulus were investigated. Local solid density measurements were performed at a test cross-section in the fully developed flow region of a concentric annulus, which is a part of a closed-loop system consisting of a head tank, a variable speed slurry pump, an orificemeter, a heat exchanger, an annulus, a temperature probe, and a drain line. The solid particles with mean diameters of 72 and 138 &amp / #61549 / m at two different feed solid concentrations of 1 and 2 % v/v were used in the prepared slurries. The dependent variables being local solid density, local mixture velocity, and axial frictional pressure drop along the test-section, an experimental work was performed to obtain the radial solid density profiles and axial pressure gradients at different operating conditions. To determine the local solid densities, a sampling probe was used. At the beginning, this probe was used as a pitot tube to measure the local velocities in the test cross-section. Making use of these data, local solid densities were measured with the same probe under isokinetic and nonisokinetic conditions to compare both. For this purpose, an isokinetic sampling unit was designed and constructed to withdraw the samples under isokinetic flow conditions, at which the sampling velocity in the probe equated to the true flow velocity in the annulus very closely. The required constant back-pressure was supplied by pressurized N2 gas to equate these velocities to each other. The amounts of solids in the slurry samples collected at seven different radial locations in the test area under isokinetic and non-isokinetic conditions were determined by the gravimetric method. Local solid densities showed more uniform trends at the feed solid concentration of 1% v/v than those at 2% v/v. Increasing the feed solid concentration and particle size changed the shape of these profiles. The obtained local solid densities were generally higher near the outer wall than those near the inner wall / this result was consistent with the literature. As a general trend, local solid densities showed a decreasing trend at around a dimensionless radial distance of &amp / #61548 / =0.4, where the slurry velocity profile had its maximum value. It was observed that the two-phase axial frictional pressure gradients along the test section in the fully developed flow region increased with increasing feed solid concentration and the particle size at a constant slurry flow rate. Isokinetic sampling results showed that the local solid densities increased consistently with the increasing slurry velocity at all radial distances in the annular gap, while this trend was not observed clearly in the non-isokinetic measurements. Also the variations of the local solid densities along the radial distance were more obvious in the isokinetic results while these variations were obscured under nonisokinetic conditions by the experimental error at a higher level.
112

Alu Insertion Polymorphisms In Anatolian Turks

Dinc, Havva 01 September 2003 (has links) (PDF)
In the present study / ten autosomal human-specific Alu insertion polymorphisms / ACE, APO, A25, B65, D1, FXIIIB, HS4.32, HS4.69, PV92 and TPA25 were analyzed in approximately 100 unrelated individuals from Anatolia. Alu insertion polymorphisms offer several advantages over other nuclear DNA polymorphisms for human evolution studies. The frequencies of the ten biallelic Alu insertions in Anatolians were calculated and all systems were found to be in Hardy-Weinberg equilibrium (p&gt / 0.05). By combining the results of this study with results of previous studies done on worldwide populations, the genetic distance (Nei&rsquo / s DA) between each pair of populations was calculated and neighbor joining trees were constructed. In general, geographically closer populations were found to be also genetically similar. Principal component analysis (PCA) was performed and Anatolia was found to be in the European cluster. As a result of PCA / it was concluded that FXIIIB, PV92 and ACE were the variables contributing the most to the explanation of the variation between the populations. Additionally / canonical variates analysis (CVA) concluded that the most discriminative markers for the groups of populations were PV92, D1, ACE and HS4.32. Pair-wise Fst values were also calculated between Anatolians and some of the populations for which the data was available. It was concluded that, Anatolians have non-significant pair-wise Fst values with Swiss and French Acadian populations. Lastly, heterozygosity vs. distance from centroid graph was constructed and it was found that Anatolians and India-Hindu had exactly the expected heterozygosity value predicted by the model of Harpending and Ward (1982).
113

R&amp / d Project Performance Evaluation With Multiple And Interdependent Criteria

Tohumcu, Zeynep 01 June 2007 (has links) (PDF)
iv In this study, an Analytic Network Process (ANP) and Data Envelopment Analysis (DEA) based approach was developed in order to measure the performance of customer-based Research and Development projects being executed in T&Uuml / BTAKSAGE, Defense Research and Development Institute, under the Scientific and Technological Research Council of Turkey. In order to evaluate project performance, many criteria, containing various subcriteria were determined. In order to handle the interdependencies among the criteria and the sub-criteria, ANP was used. The ANP model generated in this study is a hybrid model consisting of both a hierarchy and a network. The pairwise comparison matrices that were built up for defining the importance and influences of the criteria/sub-criteria in the ANP model were formed as interval judgments from a group decision making process, based on data obtained from a questionnaire conducted among the experts in the Institute. From the interval pairwise comparison matrices, weight intervals for the sub-criteria were determined and these bounds were used as assurance region constraints in a super-efficiency DEA model, through which the project ranking was obtained. Taking into consideration that there may occur some missing values in some projects for some of the sub-criteria, the superefficiency DEA model was extended to handle missing data. The model was applied to a real case study on performance evaluation of the ongoing customer-based projects in the Institute. For comparison purposes, the case study was also solved by two other approaches.
114

Approaches For Multiobjective Combinatorial Optimization Problems

Ozpeynirci, Nail Ozgur 01 January 2008 (has links) (PDF)
In this thesis, we consider multiobjective combinatorial optimization problems. We address two main topics. We first address the polynomially solvable cases of the Traveling Salesperson Problem and the Bottleneck Traveling Salesperson Problem. We consider multiobjective versions of these problems with different combinations of objective functions, analyze their computational complexities and develop exact algorithms where possible. We next consider generating extreme supported nondominated points of multiobjective integer programming problems for any number of objective functions. We develop two algorithms for this purpose. The first one is an exact algorithm and finds all such points. The second algorithm finds only a subset of extreme supported nondominated points providing a worst case approximation for the remaining points.
115

Evaluation Of Concrete Face Rockfill Alternative For Dam Type Selection: A Case Study On Gokceler Dam

Korkmaz, Seda - 01 June 2009 (has links) (PDF)
In this study a recent dam type, concrete face rockfill dam (CFRD), its design and behaviour is overviewed. The design features of G&ouml / k&ccedil / eler Dam are introduced as a case study. Selection of concrete face rockfill type for G&ouml / k&ccedil / eler Dam Project is discussed together with the other two alternatives, namely earth core rockfill (ECRD) and roller compacted concrete (RCC) dam. G&ouml / k&ccedil / eler Dam type selection as concrete face rockfill dam is also verified by an economic analysis conducted calculating internal rate of return for all alternative types. In cost analysis a currency independent defined unit cost (DUC) is specified to verify the time independent validity of the economic analysis.
116

Grape Juice Filtration, Thermopyhsical Properties Of Clear Fruit Juices And Pressurized Low Polarity Water (plpw) Extraction Of Polyphenolic Compounds From Grape Canes

Karacabey, Erkan 01 September 2009 (has links) (PDF)
Filtration of grape juice was investigated. Effects of process parameters of filtration were examined. The usage of precoating material and filter aid were found to be necessary to prolong the filter life. Filter cake was found to be incompressible with the effect of increasing pressure. Increase in temperature caused increase in flow rate due to the reduction in viscosity. The influences of depectinization and clarification on filtration process were also examined. Depectinization and clarification decreased the resistance and increased the flow rate. Improvement in the quality of the grape juice was observed when these pretreatments were employed. The effects of temperature and soluble solid concentration on physical properties of clarified fruit juices were investigated. High temperature and soluble solid content dependencies of density, viscosity and heat capacity were detected. Experimental data were fitted as a function of temperature and soluble solid content. Models being valid for studied clarified fruit juices were achieved for density and viscosity with the regression coefficients (R2) higher than 0.90. Optimization of the solid-liquid extraction conditions for trans-resveratrol, trans-&amp / #949 / -viniferin, ferulic acid, and total phenolics from milled grape canes has been investigated. Temperature and ethanol concentration were found to be major process variables for all responses. Maximum yields of trans-resveratrol, trans-&amp / #949 / -viniferin, ferulic acid, and total phenolics were predicted as 4.25 mg/g dw, 2.03 mg/g dw, 1.05 mg/g dw, and 9.28 mg/g dw, respectively. Optimization of extraction conditions for antioxidant activity of grape cane extracts measured by the Trolox equivalent antioxidant capacity (TEAC) and the oxygen radical absorbance capacity (ORACFL) assays was carried out using solid-liquid extraction and response surface methodology. Ethanol concentration and temperature employed for the extraction of antioxidant agents from grape cane samples were found to be statistically significant process variables affecting antioxidant activity measured by the TEAC and ORAC methods. trans-Resveratrol and trans-&amp / #949 / -viniferin were extracted from milled grape canes using pressurized low polarity water (PLPW). The extraction temperature was significant for both compounds: extraction at 160oC resulted in a 40% loss of trans-resveratrol compared to 95oC while reduction of trans-&amp / #949 / -viniferin at both temperatures remained at 30%. Increasing ethanol concentration from 0 to 25% increased the extraction of total phenolics and trans-&amp / #949 / -viniferin by 44% and 489%, respectively. Solvent flow rate also influenced trans-&amp / #949 / -viniferin extraction. Effective diffusivities of trans-resveratrol increased by three times with increasing temperature. The modified Gompertz equation satisfactorily explained the extraction of the stilbenes investigated.
117

An Empirical Relationship Based On High-pass Filtering To Estimate Usable Period Range For Nonlinear Sdof Response

Kale, Ozkan 01 December 2009 (has links) (PDF)
High-pass filtering that is one of the most efficient methods in removing long-period noise of accelerograms is investigated for its effect on nonlinear oscillator deformation response. Within this context, uncertainty in filter cut-off periods that would significantly modify the low-frequency content of accelerograms come into prominence for obtaining reliable long-period displacement response. Analog and digital ground-motion records from recently compiled Turkish strong-motion database are used and these records are high-pass filtered with a consistent methodology by randomly generated filter cut-offs that represent different filter cut-off decisions of the analysts. The uncertainty in inelastic spectral and residual displacements (SDIE and SDR, respectively) due to variations in filter cut-offs is examined to derive the usable period ranges where the effect of high-pass filtering is tolerable. Non-degrading, stiffness degrading and stiffness and strength degrading oscillator behavior are considered in these analyses. The level of nonlinear behavior in single degree of freedom (SDOF) response is described by varying the yield strength (R, normalized yield strength) and displacement ductility (&micro / ) levels. The usable period ranges that depend on magnitude, recording quality, level of inelasticity and level of degradation are determined for SDIE through robust probabilistic methodologies.
118

Buildings Under Recurring Near-field Earthquakes

Bayhan, Beyhan 01 October 2010 (has links) (PDF)
Prior to this study, to our best knowledge, no cast-in-place, older-type RC building has ever been subjected to near-field strong ground motions from three major earthquakes. This happened in an indirect way in Turkey over a time span of eleven years. Three identical buildings belonging to Ministry of Public Works and Resettlement (MPWR) that had been built to the same design templates, experienced March 13th 1992 Erzincan earthquake in Erzincan, November 12th 1999 D&uuml / zce earthquake in Bolu and May 1st 2003 Bing&ouml / l earthquake in Bing&ouml / l, respectively. The ground motion sensor stations were fortuitously nearby in an adjacent single-story building in Bolu and Bing&ouml / l. The station in Erzincan was in a single-story building about 2 km away from the case study building but we assume that the record applies to the building there. These three data represent characteristics of near-field ground motions and the distance of the sensor stations to the nearest fault trace was less than 10 km. The buildings sustained varying degrees of damage during the earthquakes and their damage survey was employed through site investigations. Given that the damage information, input motions, design drawings and material properties of the buildings are all known, this provided an opportunity to predict the structural damage to these buildings by proper modeling using the tools of current computational performance assessment procedures. In this circumstance, three dimensional (3D) analytical models of the MPWR buildings have been performed. Bi-directional excitations have been applied to the models by nonlinear time history analyses (NTHA). The results illustrate that NTHA are capable of indicating the occurrence of shear failure in captive columns / however, they overestimate the global damage level for all buildings. The overestimation is more significant in Erzincan case where the building sustained a pulse-type motion without significant distress.
119

Incentive, Subsidy, Penalty Mechanisms And Pooled, Unpooled Allocation Of Production Capacity In Service Parts Management Systems

Atak, Erman 01 July 2011 (has links) (PDF)
In this thesis, two systems are analyzed in order to gain insight to the following issues: (i) Effect of incentive, subsidy and penalty designs on decentralized system, (ii) effect of using production facility as pooled capacity (pooled system) and dedicated capacity (unpooled system) on capacity utilization and system profit. Regarding the first issue, three models are defined / decentralized model, centralized model and decentralized model with incentive, subsidy, penalty designs. In all models, there are two dealers and one item is under consideration and lateral transshipments are allowed. Dealers operate with four inventory level decision (strategies) that consists of base stock level, rationing level, transshipment request level and customer rejection level. Under the decentralized system, a dealer sets its operating strategy according to the strategy of the other dealer and maximizes its own infinite horizon discounted expected profit. In the centralized system, a central authority (say manufacturer) exists, which considers the system-wide infinite horizon discounted expected profit, and makes all decisions. Under decentralized system with incentive, subsidy, penalty designs, manufacturer tries different designs on decentralized system namely revenue sharing, holding cost subsidy, request rejection penalty, transportation cost subsidy and commission subsidy in order to v align decentralized system with centralized system. According to the results obtained, this alignment works best with nearly 40% revenue sharing percentage, low rejection penalty, high transportation cost subsidy under low transportation cost and commission subsidy under very low or very high commissions. Holding cost subsidy, on the other hand, is not a good strategy since it declines decentralized system profit. Considering the second issue, two systems are examined / pooled system and unpooled system. Both systems are centrally managed. In the pooled system, all capacity is dynamically allocated to either dealer considering maximization of system profit. In the unpooled system, capacity is shared among dealers and dealers are always allocated same percentage of the capacity. Infinite horizon average expected profit is maximized in both systems. The dealer having lower holding cost is allocated higher capacity in both pooled and unpooled system / however, exceptions exist in the unpooled system under low arrival rate. Highrevenue dealer is always allocated higher capacity in both pooled and unpooled system. Arrival rate affects both systems such that total capacity utilization increases with increasing arrival rate. From the profit point of view, pooled system has great advantage under low demand rate in general.
120

Microarray Applications For Determination Of The Effects Of Emodin On Breast Cancer Cell Lines

Qomi Ekenel, Emilia 01 March 2011 (has links) (PDF)
ABSTRACT MICROARRAY APPLICATIONS FOR DETERMINATION OF THE EFFECTS OF EMODIN ON BREAST CANCER CELL LINES Ekenel Qomi, Emilia M.S., Department of Biotechnology Supervisor: Prof. Dr. Mesude Iscan Co-Supervisor: Assoc. Prof. Dr. Nursen &Ccedil / oruh February 2012, 191 pages Cancer is a genetic disease that is characterized by uncontrolled cells growth. Breast cancer is a type of cancer originating from breast tissue. Some breast cancers are sensitive to hormones such as estrogen which makes it possible to treat them by blocking the effects of these hormones in the target tissues. These require less aggressive treatment than hormone negative cancers. Breast cancers without hormone receptors, are higher-risk, and are treated more aggressively. The aim of our study is to investigate the effect of emodin on MCF-7 which is ER (estrogen receptor) positive, and MDA-MB-231 (ER negative) cancerous cell lines. Emodin which is a phytoestrogen component, extracted from rheum (genus) plant, has been reported to suppress the growth of tumor in some clinical situation, and it&rsquo / s found that emodin induced apoptosis through the decrease of Bcl-2/Bax ratio and the increase of cytoplasm cytochrome c concentration in human breast cancer Bcap-37 cells. Comparing the effect of emodin between ER positive and ER negative cells at the molecular level was investigated by Microarray analysis of gene expressions using Affymetrix Human Genome U133 plus 2.0 Array. The microarray data analysis was performed by using BRB-Array Tools, v.4.2.0. GST and its classes / Alpha, Mu, Pi, Theta, Sigma, Omega, Zeta and Kappa is our interested genes because of its role in regulating susceptibility to cancer, by their ability to metabolize reactive electrophilic intermediates to usually less reactive and more water soluble glutathione conjugates. And also its have a role in detoxifying the damage caused by oxidative stress which is a result of the radiotherapy. v The differentially expressed genes from emodin treated and untreated control breast cancer cell lines were compared after normalization and filtering and annotated, it was shown that the top 10 highly (significantly) varied genes belong to the biological processes such as (namely) cell cycle, cell division, cell proliferation, mitosis and meiosis, this insure the relation of emodin to the cell growth processes in the cancerous cells. The analysis of the change on the cell growth confirmed the anti-tumor effect of emodin. About the effect of emodin treatment on MCF-7 and MDA-MB-231 cancerous cell lines separately / Both cells its significant genes was belong to cell growth biological processes, in MCF-7 cells in-addition other biological processes was shown, for example / stimulus to estradoil response, and the metabolism of xenobiotic by cytochrome p450, so CYP1A1 gene code for a protein which is used in emodin metabolism. The varied gene number was nearly 4400 gene from the scatter plot result in MCF-7 cells while in MDA-MB-231 cells it was nearly 3400 gene, these result insured the effect of emodin as a phytoestrogenic component as MCF-7 cells are ER positive cells, so emodin bind to the ER in MCF-7 cells and affected more gene number than MDA-MB-231. More number of GST enzyme classes changed in MCF-7 cells than MDA-MB-231, and the effect of emodin as anti-cancer showed different change of GST genes between MCF-7 and MDA-MB-231. The results confirmed by network analysis done, to find the most related genes to our top 10 regulated gene list, and these genes were analyzed / most of them where in our gene list, and their regulation after emodin treatment analyzed and the result was supported to emodin as anti-tumor and phytoestrogenic component.

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