The objective of this study is to determine hydrate formation conditions of methane- hydrogen sulfide mixtures. During the study, an experimental work is carried out by using a system that contains a high-pressure hydrate formation cell and pressure-temperature data is recorded in each experiment. Different H2S concentrations and both brine and distilled water are used in the experiments and the Black Sea conditions, which are suitable for methane-hydrogen sulfide hydrate formation are examined. Considering the pressure-temperature data obtained, hydrate equilibrium conditions are determined as well as the number of moles of free gas in the hydrate formation cell. The change in the number of moles of free gas in the hydrate formation cell with respect to time is considered as a way of determining rate of hydrate formation. Effects of H2S concentration and salinity on hydrate formation conditions of methane-hydrogen sulfide mixtures are also studied. It is observed that an increase in the salinity shifts the methane-hydrogen sulfide hydrate equilibrium condition to lower equilibrium temperatures at a given pressure. On the other hand, with an increase in H2S concentration the methane hydrogen sulfide hydrate formation conditions reach higher equilibrium temperature values at a given pressure. After the study, it can be also concluded that the Black Sea has suitable conditions for hydrate formation of methane hydrogen sulfide mixtures, considering the results of the experiments.

Group of piles are widely used deep foundation systems to resist lateral and vertical loads. Seismic and static performance of pile groups mostly depend on soil type, pile spacing and pier rigidity. Not many pile lateral load tests have been performed due to high costs. Advanced and complex analytical methods were developed over the years to assess nonlinear lateral pile response. This research is conducted aiming at developing a practical analysis method to verify the lateral performance of pile groups and its effect on overall response of bridge utilizing the available pile lateral load test data. Empirical constants derived from evaluation of lateral load tests are used in a simple formulation to define the nonlinear behavior of the pile-soil system. An analysis guideline is established to model the nonlinear soil-bridge interaction by the help of a general purpose structural analysis program comprising recommendations for various cases. Results of the proposed method is compared to the results of industry accepted advanced methods using response spectrum and nonlinear time history analyses to assess the suitability of this new application. According to the analysis results, proposed simple method can be used as an effective analysis tool for the determination of response of the superstructure.

Crime is a behavior disorder that is an integrated result of social, economical and environmental factors. In the world today crime analysis is gaining significance and one of the most popular subject is crime prediction. Stakeholders of crime intend to forecast the place, time, number of crimes and crime types to get precautions. With respect to these intentions, in this thesis a spatio-temporal crime prediction model is generated by using time series forecasting with simple spatial disaggregation approach in Geographical Information Systems (GIS). The model is generated by utilizing crime data for the year 2003 in Bah&ccedil / elievler and Merkez &Ccedil / ankaya police precincts. Methodology starts with obtaining clusters with different clustering algorithms. Then clustering methods are compared in terms of land-use and representation to select the most appropriate clustering algorithms. Later crime data is divided into daily apoch, to observe spatio-temporal distribution of crime. In order to predict crime in time dimension a time series model (ARIMA) is fitted for each week day, Then the forecasted crime occurrences in time are disagregated according to spatial crime cluster patterns. Hence the model proposed in this thesis can give crime prediction in both space and time to help police departments in tactical and planning operations.

The aim of this thesis is to determine the state of occupational health and safety of the construction industry among other industries in Turkey. For this purpose, data such as the number of occupational diseases, the number of occupational injuries, the number of cases of permanent incapacity to work and the number of fatal occupational injuries in each industry are derived from official sources. The comparison of the construction industry with other industries in terms of occupational health and safety is made with the comparative measures calculated with these data. In addition, it is intended to determine some characteristics of the occupational injuries and victims in the construction industry. Therefore, the distribution of more than 22,700 data concerning occupational injuries according to some selected variables is taken into account.

In this study, the load bearing behavior of piled raft foundations is investigated performing laboratory and field tests. Piled raft foundation of a multi storey building was also instrumented and monitored in order to study the load sharing mechanism of piled raft foundations. A small reinforced concrete piled raft of 2.3 m square supported by four mini piles at the corners was loaded and contribution of the raft support up to 41 % of the total load was observed. The soil was stiff fissured Ankara clay with no ground water. A building founded on a piled raft foundation was instrumented and monitored using earth pressure cells beneath the raft during its construction period. The foundation soil was a deep graywacke highly weathered at the upper 10 m with no ground water. The proportion of load that was carried by the raft was 21 to 24 % of the total load near the edge and 44 to 56 % under the core. In the laboratory tests, model aluminum piles with outerinner diameters of 2218 mm and a length of 200 mm were used. The raft was made of steel plate with plan dimensions of 176 mm x 176 mm and a thickness of 10 mm. The model piles were instrumented with strain gages to monitor pile loads. Model piled raft configurations with different number of piles were tested. The behavior of a single pile and the plain raft were also investigated. The soil in the model tests was half and half sand &ndash / kaolinite mixture. It has been observed that when a piled raft is loaded gradually, piles take more load initially and after they reach their full capacity additional loads are carried by raft. The proportion of load that was carried by the raft decreases with the increasing number of piles and the load per pile is decreased. Center, edge and corner piles are not loaded equally under rafts. It has been found that rafts share foundation loads at such levels that should not be ignored.

Since 1976, the General Directorate of Disaster Affairs of Turkey has deployed several strong-motion accelerographs at selected sites. Within the framework of the project entitled Compilation of National Strong Ground Motion Database in Accordance with International Standards, initiated in 2006, site conditions at a total of 153 strong-motion sites were investigated within the uppermost 30 m depth through boreholes including Standard Penetration Testing and surface seismics by means of Multi-channel Analysis of Surface Waves (MASW). In this study, firstly, the assessment of the site characterization was held by making use NEHRP Provisions, EC-8 and Turkish Seismic Design Code. The corrected penetration resistances are calculated and observed how it affects the classification. In addition, the consistency of site classes obtained from either penetration resistance or shear wave velocity criteria is examined. Also the consistency of the boundaries of the site classes in terms of shear wave velocity and penetration resistance data pairs are investigated. Secondly, the liquefaction potential of these sites is examined. Thirdly and finally, the shear wave velocity profiles obtained from MASW technique are contrasted to other seismic tests.

Soil moisture condition of a watershed plays a significant role in separation of rainfall into infiltration and surface runoff, and hence is a key parameter for the majority of physical hydrological models. Due to the large difference in dielectric constants of dry soil and water, microwave remote sensing and particularly the commonly available synthetic aperture radar is a potential tool for such studies. The main aim of this study is to produce the distributed soil moisture maps of a catchment from active microwave imagery. For this purpose, nine field trips are performed within a small basin in western Anatolia and point surface soil moisture values are collected with a Time Domain Reflectometer. The field studies are planned to match radar image acquisitions and accomplished over the water year of 2004 - 2005. In this context, first, the Dubois Model, a semi-empirical backscatter model is utilized in the reverse order to develop radar backscatter &amp / #8211 / soil roughness relationship and soil roughness maps of the study area are obtained. Then another relationship is built between radar backscatter and the three governing surface parameters: local incidence angle, soil moisture and soil roughness, which is later used in the soil moisture estimation methods. Depending on land use and vegetation cover condition, surface soil moisture maps of the catchment are produced by Backscatter Correction Factors, Water Cloud Model and Basin Indexes methods. In the last part of the study, the soil moisture maps of the basin are input to a semi-distributed hydrological model, HEC-HMS, as the initial soil moisture condition of a flood event simulation. In order to investigate the contribution of distributed initial soil moisture data on model outputs, simulation of the same flood event is also performed with the lumped initial soil moisture condition. Finally, a comparison between both the distributed and lumped model simulation outputs and with the observed data is carried out.

In this study the incipient motion of coarse solitary particles having different specific weights and shapes was investigated. A tilting flume of rectangular cross-section having a net working length of 12 m was used through the experiments. The slope of the channel and the discharge in the channel are the two basic variable parameters that determine the initiation of motion. Particles made of cement and mixture of cement and iron dust in certain ratios were used in the experiments with an obstructing element of various heights right behind the particles. Dimensionless hydraulic parameters determined from theoretical analysis were related to each other. Velocity profiles over the flow depths were measured and flow conditions corresponding to critical conditions were evaluated in terms of critical velocities and shear velocities. The findings of this study were compared with the results of similar studies given in the literature.

The aim of the thesis, is to find the transient force applied by an individual transient liquid slug on an elbow at the end of a horizontal line due to an impact. The liquid slug is driven by pressurized air in a tank located upstream of the pipeline. The time dependent pressure distribution along the elbow and a vertical extension segment after the elbow was solved, with a 1-D numerical approach along a curved line mesh. For this purpose / firstly, a 3-D axial turbulent velocity profile function was assumed for the slug, with its shape allowed to sway towards the convex side of the elbow along the curved mesh with the aid of a calibration tool. Then, the pressure values were calculated by using 1-D application of Reynolds Equations in cylindrical polar and cartesian coordinates for the elbow and the vertical extension segment, respectively. The transient force acting on the elbow and the following vertical extension segment was found by using these calculated pressure values and applying conservation of momentum principle over the volume elements selected along the elbow and the vertical extension segment. For the analysis of the slug motion from the pressurizer tank to the elbow, a previously written computer code BOZKUS-2 was utilized. Then, the elbow and the vertical extension segment calculations in this study were made with a new code KAYHAN, which is an improved version of BOZKUS-2. The calculated transient force and impact pressures at the elbow were also compared with those from previous studies.

Disinfection of the municipal water systems is mostly achieved by means of chlorine addition at water treatment plants known as sources. Thus, there should be an adequate chlorine concentration at the source for an effective disinfection throughout the system by considering upper and lower limits of disinfectant. However, since the disinfectants are reactive and decays through the system, chlorine added at the source may not be enough to maintain desired disinfectant residuals which may lead to water quality problems in the water distribution system. Moreover, the disinfectants such as chlorine has also an effect to be carcinogen due to formation of disinfectant by-products. Thus, the system should balance the amount of disinfectant supplied while minimizing the health risk. In such a case, it is recommended that one or more booster disinfection stations can be located throughout the system. Such a method can provide more uniform distribution of the chlorine concentration while reducing the amount of the disinfectant used. In this thesis, optimum scheduling, and injection rates of the booster disinfection stations have been searched. The objective is to minimize the injected mass dosage rate subjected to the provision of adequate and more uniform residual concentration in the network. Determination of variable network hydraulics and chlorine concentrations is held out by EPANET network simulation sofware. A C++ code was developed to interface with EPANET by means of the EPANET Programmer&#039 / s Toolkit for linear optimization of the disinfectant mass dosage rate applied to the network.