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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.
1

Geology And Petrology Of Beypazari Granitoids: Yassikaya Sector

Billur, Basak 01 December 2004 (has links) (PDF)
Beypazari Granitoid is a low temperature and shallow-seated batholite intruded the Tepek&ouml / y metamorphic rocks of the Central Sakarya Terrane. Composition of the granitoid varies from granite to diorite. The granitoid is unconformably overlain by Palaeocene and Eocene rock units. Thus the age is probably Late Cretaceous. The Beypazari Granitoid comprises mafic microgranular enclaves. The granitoid mainly consists of quartz, plagioclase, orthoclase and minor amphibole, biotite, chlorite, zircon, sphene, apatite, and opaque minerals. Plagioclase shows sericitation whereas biotite and hornblende, chloritization. Holocrystalline and hypidiomorphic are characteristic textures of the granitoid. Geochemically, the Beypazari Granitoid is calc-alkaline, metaluminous and I-type. REE data indicate that it may have been generated from a source similar to the upper continental crust. The trace element data of the Beypazari Granitoid suggest a volcanic arc tectonic setting. The possible mechanism of Beypazari granitoid is the northdipping subduction of Neo-Tethyan northern branch under Sakarya continent during Late Cretaceous. The Beypazari Granitoid may be related with Galatean volcanic arc granitoids.
2

Achieving A Pedestrian Oriented Transportation System In Ankara

Yasdag, Serkan 01 May 2006 (has links) (PDF)
After World War II, automobile use expanded rapidly in the developed countries. As a result, travel pattern changed entirely and automobile has become the dominant form of transport in cities. As a result, the city has been shaped and sized in response to automobile needs. Such increase caused traffic problems in the Central Business Districts and surrounding areas. The problems of traffic congestion and pedestrian circulation have become an important issue in the whole city. As traffic problems have grown in developed cities, they had to be engaged in managing travel demand of people in order to provide mobility and access with reference to the advancing principles of sustainability. In this scope, this study shows the need of travel demand management to create a sustainable transport system. As a case, this study will evaluate the transport problems of Ankara and the place of the city in the urban transport policy process. At this point, transport problems and the transformation of road network and their impacts on the city will be examined in four periods. As a conclusion, urban transportation strategies needed for creating a sustainable transport system are overviewed for the city of Ankara.
3

A Comparative Assessment Of An Existing Reinforced Concrete Building By Using Different Seismic Rehabilitation Codes And Procedures

Ozturk, Ismail 01 January 2007 (has links) (PDF)
Lateral load carrying capacities of reinforced concrete structures which are designed by considering only gravity loads or according to outdated earthquake codes can be insufficient. The most important problem for these buildings is the limited ductility of the frame elements. How to evaluate the performance of an existing structure and to what level to strengthen it had been major concerns for structural engineers. Recent earthquakes which occurred in the Marmara Region in the last decade have increased the number of seismic assessment projects drastically. However, there was no special guideline or code dealing with the assessment of existing buildings. In order to have uniformity in assessment projects, a new chapter has been included in the revised Turkish Earthquake Code (2006). In this study, the existing and retrofitted conditions of a reinforced concrete building were assessed comparatively by employing linear and nonlinear assessment procedures according to different seismic rehabilitation codes. The study was carried out on a six storey reinforced concrete telephone exchange building. Although there was no damage in the structure due to the recent earthquakes that occurred in the Marmara Region, the building was assessed and retrofitted in 2001 by using equivalent lateral load analysis results. The results of linear and nonlinear assessment procedures performed in the scope of this thesis, were also compared with the assessment results of this previous study. In the nonlinear assessment procedures, pushover analysis results were used. In addition to comparison of the assessment procedures, efficiency of a widely used approximate pushover method was also investigated.
4

Multi-robot Coordination Control Methodology For Search And Rescue Operations

Topal, Sebahattin 01 September 2011 (has links) (PDF)
This dissertation presents a novel multi-robot coordination control algorithm for search and rescue (SAR) operations. Continuous and rapid coverage of the unstructured and complex disaster areas in search of possible buried survivors is a time critical operation where prior information about the environment is either not available or very limited. Human navigation of such areas is definitely dangerous due to the nature of the debris. Hence, exploration of unknown disaster environments with a team of robots is gaining importance day by day to increase the efficiency of SAR operations. Localization of possible survivors necessitates uninterrupted navigation of robotic aiding devices within the rubbles without getting trapped into dead ends. In this work, a novel goal oriented prioritized exploration and map merging methodologies are proposed to generate efficient multi-robot coordination control strategy. These two methodologies are merged to make the proposed methodology more realistic for real world applications. Prioritized exploration of an environment is the first important task of the efficient coordination control algorithm for multi-robots. A goal oriented and prioritized exploration approach based on a percolation model for victim search operation in unknown environments is presented in this work. The percolation model is used to describe the behavior of liquid in random media. In our approach robots start prioritized exploration beginning from regions of the highest likelihood of finding victims using percolation model inspired controller. A novel map merging algorithm is presented to increase the performance of the SAR operation in the sense of time and energy. The problem of merging partial occupancy grid environment maps which are extracted independently by individual robot units during search and rescue (SAR) operations is solved for complex disaster environments. Moreover, these maps are combined using intensity and area based features without knowing the initial position and orientation of the robots. The proposed approach handles the limitation of existing works in the literature such as / limited overlapped area between partial maps of robots is sufficient for good merging performance and unstructured partial environment maps can be merged efficiently. These abilities allow multi-robot teams to efficiently generate the occupancy grid map of catastrophe areas and localize buried victim in the debris efficiently.
5

Analysis Of Forging For Three Different Alloy Steels

Civelekoslu, Baris 01 December 2003 (has links) (PDF)
Forging is a manufacturing process which is preferred among the others in that, the final product shows more enhanced properties. The properties of the final product are directly related with the material used in the forging process. Main parameters such as forging temperature, number of stages, preform design, dimensions of the billet, etc. may be affected by the forging material. Alloys are one of the main areas of interest in the forging industry. The use of alloy steels may bring superior properties, especially in terms of strength and forgeability. In this study, three different alloy steels, which are hot forged in industry have been examined. The flow of the material, stress distribution, die filling and the effects of the process parameters on the forging have been investigated. Three industrial forging parts / M20 and M30 eye bolts and a runner block have been studied. Finite Volume Analysis of the forging process has been performed for carbon steels / C45 and C60 and alloy steels / a stainless steel X20Cr13, a heattreatable alloy steel, 42CrMo4 and a bearing steel, 100Cr6. The results of the simulations have been compared with the findings of the experiments carried out in a forging company. It has been observed that numerical and experimental results are in good agreement.
6

Pressurized Liquid Extraction Of Phenolic Compounds From Fruit Pomaces

Hasbay Adil, Incinur 01 August 2006 (has links) (PDF)
In this study, extraction of phenolic compounds from sour cherry, peach and apple pomaces using high pressure extraction (HPE) and subcritical CO2 extraction (SCE) was investigated considering total phenolic content (TPC) and antiradical efficiency (AE). Different combinations of pressure (50, 125, 200 MPa), temperature (20, 40, 60&amp / #61616 / C), solid/solvent ratio (0.05, 0.15, 0.25 g/ml) and extraction time (10, 25, 40 min) were used for HPE according to the Box-Behnken experimental design. The variables used for SCE were pressure (20, 40, 60 MPa), temperature (40, 50, 60&amp / #61616 / C), ethanol concentration (14, 17, 20 wt%) and extraction time (10, 25, 40 min). For HPE, TPC and AE at the optimum conditions were 3.80 mg gae/g sample and 22 mg DPPH&amp / #729 / /g sample for sour cherry pomace, 0.93 mg gae/g sample and 6.40 mg DPPH&amp / #729 / /g sample for peach pomace and 2.08 mg gae/g sample and 10.80 mg DPPH&amp / #729 / /g sample for apple pomace, respectively. For SCE, TPC and AE at the optimum conditions were 0.60 mg gae/g sample and 2.30 mg DPPH&amp / #729 / /g sample for sour cherry pomace, 0.26 mg gae/g sample and 1.50 mg DPPH&amp / #729 / /g sample for peach pomace and 0.47 mg gae/g sample and 3.30 mg DPPH&amp / #729 / /g sample for apple pomace, respectively. Efficiency of HPE and SCE methods was compared with solvent extraction (SE). TPC and AE of the extracts obtained by HPE were close to those obtained by SE but the efficiency of SCE was low compared to HPE and SE. SCE was a better extraction method for apple and peach pomaces compared to sour cherry pomace.
7

Change In The Status Of Turkish Women During The Ottoman Modernization And Self-evaluation Of Women In Kadinlar Dunyasi Of 1913

Aygul, Ceren 01 August 2010 (has links) (PDF)
This study, which aims to portray the circumstances of Ottoman women&rsquo / s movement during the first years of Second Constitutional Era from the eyes of the writers of Kadinlar D&uuml / nyasi Periodical, makes an analysis of the meanings ascribed to the efforts for the restoration of women&rsquo / s position in social life and the roles claimed for women during Ottoman modernization period. This research intends to confirm the fact that the basis for the mentality of defenders voicing women&rsquo / s rights was the progressive outlook which chose the &ldquo / women question&rdquo / as the focus on the way of securing not only social progress but also social integration, solidarity, national consciousness and progressiveness. Thus, the ideas expressed in the articles all written by women writers of Kadinlar D&uuml / nyasi are evaluated with the question in mind that whether the boundaries of Ottoman women&rsquo / s movement and the social role granted for them in the modernization process were wholly determined by the women themselves or theorized predominantly by the policymakers of the state who were all men. Deducing from the self-evaluation of women in Kadinlar D&uuml / nyasi of 1913, this thesis consequently underlines the fact that the struggle for women rights, which were carried out on behalf of patriotic and nationalist claims in accordance with the socio-political conditions of the time, could not overcome their invariable position of being &ldquo / historical objects&rdquo / despite of the fact that women held a considerable progress in their status during the Second Constitutional Era which laid the parameters of the &ldquo / women question&rdquo / during the early Republican Era.

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