Gas turbines are widely used as power sources in many industrial and transportation applications. This kind of engine is the most preferred prime movers in aircrafts, power plants and some marine vehicles. They have different configurations according to their mechanical constructions such as turbo-prop, turbo-shaft, turbojet, etc. These engines have different efficiencies and specifications and some advantages and disadvantages compared to Otto-Cycle engines. In this thesis, a small turbojet engine is investigated in order to find different control algorithms. AMT Olympus HP small turbojet engine has been used to determine the mathematical model of a gas turbine engine. Some important experimental data were taken from AMT Olympus engine by making many experiments. All components of the engine have been modeled by using laws of thermodynamics and some arithmetic calculations such as numerical solution of nonlinear differential equations, digitizing compressor and turbine map etc. This mathematical model is employed to create control algorithm of the engine. At first, standard control strategies had been considered such as P (proportional), PI (proportional integral), and PID (proportional-integral-differential) controllers. Because of the nonlinearities in gas turbines, standard control algorithms are not commonly used in literature. At the second stage fuzzy logic controllers have been designed to control the engine efficiently. This control algorithm was combined with mathematical of the engine in MATLAB environment and input-output relations were investigated. Finally, fuzzy logic control algorithm was embedded into an electronic controller.

Hydroxyapatite (HA) based bioceramics have been developed to treat bone defects for the last 30 years. Doping HA with elements is a common approach to increase mechanical strength, biocompatibility and osteointegrity. Bone morphogenetic protein (BMP)-containing bioceramic composites enhance osteointegrity and induce bone formation. Strontium (Sr) is currently used to treat osteoporosis clinically as this element inhibits bone resorption and stimulates bone formation. In this study, HA was doped with silicon (Si), Sr, BMP-2 and evaluated in cortical bone defect healing. Ceramics were produced and tested mechanically after characterization. Sr release from ceramics was assessed. Ceramics were further evaluated in in vitro and in vivo conditions. X-ray diffraction analysis results of HA were in line with the literature and Sr-Si-HA ceramics showed similar intensities with HA. Ceramics had 36.9 to 41.6% porosity. Compression strength of Sr1000-Si-HA ceramics was 117.5 MPa which was more than that of the other groups. Consistent Sr release was observed in the Sr1000-Si-HA and the Sr250-Si-HA groups. Sr1000-Si-HA and Sr250-Si-HA ceramics showed higher cellular proliferation rates than the other groups in vitro. BMP addition increased alkaline phosphatase activities and DNA amounts. BMP-Sr-Si-HA group presented higher (0.304&plusmn / 0.02 g/cm2) bone mineral density values than the other groups 4 weeks after implantation however differences between groups were not significant in vivo. Sr-Si-HA and BMP-Sr-Si-HA composites stimulated new bone formation at cortical bone defects of tibia according to micro computerized-tomography and histological results. Findings of this study promote future research on Sr containing bioceramics in treatment of orthopedic problems.

The main objective of this study was to determine differences, if any, in three-dimensional (3D) kinematic characteristics of the three principal punches (the jab, hook and uppercut) executed by novice, intermediate and elite level amateur boxers. Specifically, the kinematic variables related to the displacement, linear velocity and acceleration of the upper body segments, translational hand acceleration and vertical ground reaction force generated by boxers were analyzed. The subjects of this study composed of 10 novice, 9 intermediate, and 11 elite level amateur boxers. Ages of the subjects ranged from 18 to 34 years old. All subjects executed their punches toward a head-high target on a standard practice bag. The motions were captured with PhaseSpace real time optical tracking system with 8 high speed cameras at 240 fps. Then, the motions captured were analyzed to quantify the kinematic factors associated with each punch. The results showed that the uppercut punch generated larger linear shoulder, elbow and wrist velocity compared to the jab punch. Similarly, the uppercut punch generated larger linear shoulder, elbow and wrist acceleration compared to the hook and jab punches. Moreover, the uppercut and hook punches generated larger translational hand acceleration compared to the jab punch. As a conclusion, the results for all kinematic variables demonstrated that the type of punch executed was the major determinant of the magnitude of each factor studied. Moreover, the technique employed can significantly affect the resulting displacement, linear velocity and acceleration, and translational hand acceleration of the fist.

The objective of this study is to remove turbidity originating from algae present in oxidation ponds effluents by an easy and inexpensive method. For this reason, a novel lab-scale Step Feed Dual Treatment (SFDT) process was constructed and the efficiency of trickling filter (TF) to remove algae and organic matter was investigated. SFDT process developed in this study is the unique, inexpensive and new system to scavenge algae from oxidation pond effluents. In this system, influent is first treated in a stabilization pond, and subsequently they directed to a TF, so as to provide a dual treatment. Moreover, some fraction of the raw influent was directly sent to TF to maintain a steady biofilm on the TF medium. Stabilization pond was not simulated in the experimental set-up as the main objective of the study is to observe TF ability to scavenge algae from pond effluent. To determine the magnitude of the effect of individual operational parameters (hydraulic loading rate, influent COD and chlorophyll-a concentration) and of their combinations on organics and particle removal efficacy an experimental design was followed. Experiments consistent with twolevel factorial design with three variables (23) were performed. Hydraulic loading rate (HLR) (0.5-2 m3/m2.day), influent COD (150-550 mg/l) and influent chlorophyll-a concentrations (Chl-a) (250-600 &micro / g/l) were selected as independent variables. The COD and algae removal (as Chl-a) were selected as dependent variables. Data obtained from the experiments showed that when HLR (m3/m2.day) was increased from 0.5 to 2, Chl-a, NTU, SS and COD removals were decreased, however, more than 85 % removal was attained in each case, except for COD. The lowest removal efficiencies were obtained for all the quality parameters when hydraulic loading was increased to 4 m3/m2.day. It was observed that in general removal percentages for turbidity, Chl-a, SS and COD increased considerably with the decreasing hydraulic loading rate. Highest removals were obtained at lowest HLR. The removal of algae in TF was presumably due to both flocculation (due to algal and bacterial EPS production) and degradation (through bacterial activity) of algae. In conclusion, trickling filter produced clear effluents, with less than 2 NTU, for most of the cases.

ABSTRACT PREPARATION OF CROSS-LINKED TYROSINASE AGGREGATES Aytar, Burcu Selin M.S., Department of Chemical Engineering Supervisor: Prof. Dr. Ufuk Bakir June 2006, 82 pages The aim of this study was to prepare cross-linked enzyme aggregate (CLEA) from crude mushroom (Agaricus bisporus) extract. However, the optimization of CLEA production was performed by using pure tyrosinase. Important parameters were determined as protein, ammonium sulfate and glutaraldehyde concentrations, CLEA particle size, and cross-linking temperature and period. On the other hand, the order of ammonium sulfate and glutaraldehyde addition did not affect the yield of CLEA. Optimum CLEA preparation conditions were 60 % ammonium sulfate saturation, 2 % (v/v) glutaraldehyde, and 3 hour cross-linking reaction at room temperature. Particle size of the CLEAs should be reduced by mechanical stirring to eliminate mass transfer limitations. Under these circumstances, 100 % recovery was obtained from both pure and crude tyrosinases. Optimum temperature and the activation energy for catechol oxidation were determined as 34 oC and 16.9 kcal/mol for CLEAs, whereas, 32 oC and 12.5 kcal/mol for the free enzyme. Furthermore, the thermostability of CLEAs was significantly higher than the free enzyme. CLEAs, prepared from crude mushroom extract, retained 72 % of its maximum activity in eight months storage at 4 oC. Moreover, changing the storage temperature from 4 oC to room temperature did not decrease CLEAs stabilities.

Cavitating venturies are one of the simplest devices to use on a flow line to control the flow rate without using complex valve and measuring systems. It has no moving parts and complex electronic systems. This simplicity increases the reliability of the venturi and makes it a superior element for the military and critical industrial applications. Although cavitating venturis have many advantages and many areas of use, due to the complexity of the physics behind venturi flows, the characteristics of the venturies are mostly investigated experimentally. In addition, due to their military applications, resources on venturi flows are quite limited in the literature. In this thesis, venturi flows are investigated numerically and experimentally. Two dimensional, two-dimensional axisymmetric and three dimensional cavitating venturi flows are computed using a commercial flow solver FLUENT. An experimental study is then performed to assess the numerical solutions. The effect of the inlet angle, outlet angle, ratio of throat length to inlet diameter and ratio of throat diameter to inlet diameter on the discharge coefficient, and the oscillation behavior of the cavitating bubble are investigated in details.

There are many heavy oil reservoirs with thin pay zones (less than 10 m) in the world and in Turkey. Conventional steam injection techniques are not costeffective for such reservoirs, due to excessive heat loss through the overburden. Heat losses can be minimized through controlled heating of the pay zone. One such way is to introduce heat to the reservoir in a controlled manner is microwave heating. Laboratory studies on microwave heating of a scaled model of a heavy oil reservoir with a thin pay zone are presented with an economical feasibility of the method. In this thesis, three different conceptual oil reservoirs from south east Turkey are evaluated: Bati Raman (9.5 API) and &Ccedil / amurlu (12 API) heavy crude oils and paraffinic Garzan (26 API)crude oil. Using a graphite core holder packed with crushed limestone with crude oil and water microwave effects of operational parameters like heating time and waiting period as well as rock and fluid properties like permeability, porosity, wettability, salinity, and initial water saturation are studied. The main recovery mechanisms for the experiments are viscosity reduction and gravity drainage. An analytical model is developed by coupling heat equation with the electromagnetic dissipated power per unit of volume based in Maxwell&#039 / s equation successfully models the experiments for temperatures less than the pyrolysis temperature is presented. Also the experiments are scaled to the model by geometric similarity concept. In economic evaluation, the cost of oil is calculated based on domestic electricity prices.

Tomato has been genetically modified for providing properties such as insect-resistance or delayed-ripening. Tomato seeds purchased from several bazaars and markets were screened for the presence of genetic modification by targeting NptII kanamycin resistance, Nos terminator, and 35S promoter gene regions which are the most commonly transformed gene regions in transgenic plants, and then ripening-delayed tomato seeds were tried to be identified in this study. F type truncated-PG gene and Sam-k gene were selected as the indicator of genetically modified ripening delayed tomatoes. DNAs of 25 seed samples were isolated by CTAB method and examined with several primer pairs, and the primer sets that provided consistent results were selected to conduct routine testing by PCR analysis of the samples. In screening analysis via conventional PCR, 4 samples were amplified with 35S, Nos and NptII primer sets. Among other samples, 3 of them were amplified with 35S and Nos primer sets and 2 of them were amplified only with 35S primer set. The amplification was observed with Nos, NptII and Sam-k primers in one sample and this sample was identified as 35 1 N, since the sequence result of the PCR product amplified with Sam-k primers showed high homology with the Samase gene of T3 Coliphage. F type truncated PG gene was not observed in any of the samples. Although this study demonstrates the presence of commonly used gene regions in genetically modified tomatoes, further analysis of the genetically modified ripening delayed tomato seeds via construct specificor event specific PCR techniques is needed for confirmation.

Quality of Service (QoS) support for real-time traffic is a critical issue in high speed networks. The previously proposed Delay-Limiter Switch working with the Framed-Deadline Scheduler (FDS) is a combined input-output queuing (CIOQ) packet switch that can provide end-to-end bandwidth and delay guarantees for connection-oriented traffic. The Delay-Limiter Switch works with fixed-size packets. It has a scalable architecture and can provide QoS support for connection-oriented real-time traffic in a low-complexity fashion. The Delay-Limiter Switch serves connectionless traffic by using the remaining resources from the connection-oriented traffic. In this case, efficient management of the residual resources plays an important role on the performance of the connectionless traffic. This thesis work integrates new methods to the Delay-Limiter Switch that can improve the performance of the connectionless traffic while still serving the connection-oriented traffic with the promised QoS guarantees. A new method that makes it possible for the Delay-Limiter Switch to support variable-sized packets is also proposed.

The archaeological questions of historical glass have lead to remarkable research activities such as identification and sourcing the raw materials used in the glass production, investigations of the ways in which the colors of glass can be modified due to dissolved and/or colloidal coloring agents, the furnace conditions, and the time of fritting and melting. Considering publications, it can be suggested that compositional studies of well-dated glass samples have supplied useful information concerning raw materials&rsquo / characteristics and technology of glassmaking. Within this context, the aim of this study was to determine elemental compositions and production techniques of some 13th century Seljukian Period window glasses from Alanya excavation region. During the excavations at Alanya archaeological site involving Inner Castle and out of Inner Castle many glass pieces of varying colors have been found. In this study 25 samples from the area have been examined. Elemental analyses have been carried out using X-Ray Fluorescence Spectroscopy (XRF) to determine major, minor, and trace elements. The data v obtained by XRF has revealed that all samples have typical soda-lime-silica composition with the average values of, 68.22 % (SiO2) / 11.3 % (Na2O) / and 6.7 % (CaO). Hierarchical Cluster analysis has been employed and the samples have been grouped depending on their potassium oxide (K2O) and magnesium oxide (MgO) contents which indicate the probable alkali flux source. The colors of the samples are honey-yellow, brown-yellow, navy blue, blue, turquoise, purple, and green. The coloring agents have been determined as Fe, Cu, Co, and Mn. The data from Optical Microscopy has shown that most of the window glasses might have been produced by cylinder technique. Some other samples have revealed the signs of crown technique, and some might have been produced by casting.