In this dissertation, a variety of multiband communication device antennas using the coupling-feed mechanism are presented. The coupling feed contributes additional capacitance to the antenna¡¦s input impedance which shows a high inductive component for the traditional case of using a direct feed. In the first and second antenna designs, with the coupling feed, the high input inductance of the antenna is effectively compensated. This behavior leads to a dual-resonance excitation for the lower band of the antenna. Two wide operating bands are achieved, allowing the antenna¡¦s lower and upper bands to easily cover GSM850/900 and GSM1800/1900/UMTS operation. For the last two antenna designs, owing to the coupling feed, the very large input impedance seen at antenna¡¦s lower band is greatly decreased and results in successful excitation of the one-eighth wavelength (£f/8) mode of the antenna. The specific absorption rate and hearing aid compatibility results for these mobile phone antennas are also analyzed. The effects of presence of the user¡¦s hand on the laptop computer antenna performance are also studied in this dissertation.

Liquid sloshing in a 2D tank applied on a wave energy capture system and reducing the oscillation of an offshore platform are discussed in this study. A fully nonlinear time-independent finite difference method and the forth-order Runge-Kutta method are implemented to solve the coupled motions of liquid sloshing in a 2D tank with a floating platform. When the external forcing frequency of the Dynamic Vibration Absorber System composed by a tuned liquid damper and a tuned mass damper is identical to the fundamental frequency of the tank, the external force can be effectively diminished by the sloshing-induced force. In the meantime, the maximum effect of tuned mass damper on reducing the amplitude of the floating platform appears. When the frequency of external forcing is close to the first natural frequency of the liquid tank, the coupled effect between the motions of both the tank and the platform can effectively reduce the vibration of the platform and the total energy of the whole system. The Eigenfrequency of a wave capture system is formed by the coupled effect of a liquid tank and a wave capture system. When the excitation frequency of the wave capture system is near its Eigenfrequency, the sloshing-induced force is much larger than that of external and the maximum displacement of the wave energy capture system occurs. As a result, the wave energy capacity of the wave capture system can be averagely increased to 150% by the influence of liquid sloshing in the tank.

This thesis focuses on the formulation and numerical implementation of a fully coupled continuum model for deformation-diffusion in linearized elastic solids. The mathematical model takes into account the affect of the deformation on the diffusion process, and the effect of the transport of an inert chemical species on the deformation of the solid. A robust computational framework is presented for solving the proposed mathematical model, which consists of coupled non-linear partial differential equations. It should be noted that many popular numerical formulations may produce unphysical negative values for the concentration, particularly, when the diffusion process is anisotropic. The violation of the non-negative constraint by these numerical formulations is not mere numerical noise. In the proposed computational framework we employ a novel numerical formulation that will ensure that the concentration of the diffusant be always non-negative, which is one of the main contributions of this thesis. Representative numerical examples are presented to show the robustness, convergence, and performance of the proposed computational framework. Another contribution is to systematically study the affect of transport of the diffusant on the deformation of the solid and vice-versa, and their implication in modeling degradation/healing of materials. It is shown that the coupled response is both qualitatively and quantitatively different from the uncoupled response.

Capillary electrophoresis (CE) is in comparison with other chromatographic techniques, CE has several advantages such as high resolving power, small sample volume requirement, minimal buffer consumption and high sample throughtput. As a detection technique, inductively coupled plasma mass spectrometry (ICPMS) provides the advantages of low detection limit, multielement detection, and element- and isotope-specific detection capabilities. Therefore, the use of CE as a high resolution separation technique with ICP-MS as a sensitive element specific detector is of growing interest for analytical research. Four studies in our research are described below, respectively. A preliminary study of a modified microconcentric nebulizer (CEI-100, CETAC) as the sample introduction device of capillary electrophoresis inductively coupled plasma mass spectrometry (CE-ICP-MS) for the determination of monophosphate nucleotides is described. The monophosphate nucleotides studied include adenosine 5¡¦-monophosphate (AMP), guanosine 5¡¦-monophosphate (GMP), uridine 5¡¦-monophosphate (UMP) and inosine 5¡¦-monophosphate (IMP). The species studied were well separated using a 70 cm length ¡Ñ 75 £gm id fused silica capillary while the applied voltage was set at -22 kV and a 20 mmol/L ammonium citrate/citric acid buffer (pH 4.0) containing 0.1% m/v cationic polymer (hexadimethrine bromide, Polybrene) was used as the electrophoretic buffer. The electroosmotic flow was reversed by flushing the fused silica capillary with 0.2% m/v Polybrene to accelerate separation. The detection limit of various species studied was in the range of 0.036~0.054 £gg P/mL, which corresponded to the absolute detection limit of 1.1~1.6 pg P based on the injection volume of 30 nl. We determined the concentrations of nucleotides in two IG-enriched monosodium glutamates purchased from the local market. The recovery was in the range of 100~112% for various species, and the concentrations of IMP and GMP in these samples were in the range of 0.15¡V0.18% m/m. Capillary electrophoresis dynamic reaction cellTM inductively coupled plasma mass spectrometry (CE-DRC-ICP-MS) for the determination of sulfur-containing amino acids is described. The sulfur-containing amino acids studied include L-cysteine, L-cystine, DL-homocystine and L-methionine. The species studied were well separated using a 70 cm length ¡Ñ 75 £gm i.d. fused silica capillary while the applied voltage was set at +22 kV and a 10 mmol/L disodium tetraborate buffer (pH 9.8) containing 0.1 mmol/L EDTA and 0.5 mmol/L Triton X-100 was used as the electrophoretic buffer. The sulfur-selective electropherogram was determined at m/z 48 as 32S16O+ by using its reaction with O2 in the reaction cell. The method avoided the effect of polyatomic isobaric interferences at m/z 32 caused by 16O16O+ and 14N18O+ on 32S+ by detecting 32S+ as the oxide ion 32S16O+ at m/z 48, which is less interfered. The detection limit of various species studied was in the range of 0.047~0.058 £gg S/mL, which corresponded to the absolute detection limit of 1.3~1.6 pg S based on the injection volume of 27 nl. We determined the concentrations of selected sulfur-containing amino acids in urine and nutritive complement samples. The recovery was in the range of 92~128% for various species. Capillary electrophoresis-dynamic reaction cell inductively coupled plasma mass spectrometry (CE-DRC-ICP-MS) for the speciation of iron (III/II), vanadium (V/IV) and chromium (VI/III) is described. Two different CE migration modes were employed for separating the six metal ions using pre-capillary complexation. One is counter-electroosmotic mode in which iron (III/II) and vanadium (V/IV) ions were well separated using a 60 cm ¡Ñ 75 £gm i.d. fused silica capillary. The voltage was set at +22 kV and a 15 mmol/L tris(hydroxymethyl)aminomethane (Tris) buffer (pH 8.75) containing 0.5 mmol/L ethylenediaminetetraacetic acid (EDTA) and 0.5 mmol/L ortho-phenanthroline (phen) was used as the electrophoretic buffer. The other is co-electroosmotic mode in which chromium (VI/III) ions were well separated while the applied voltage was set at −22 kV and a 10 mmol/L ammonium citrate buffer (pH 7.7) containing 0.5 mmol/L diethylenetriaminepentaacetic acid (DTPA) and 0.01% polybrene was used as the electrophoretic buffer. The mass spectra were measured at m/z 51, 52 and 56 for V, Cr and Fe, respectively. The interfering polyatomic ions of 35Cl16O+, 40Ar12C+ and 40Ar16O+ on 51V+, 52Cr+ and 56Fe+ determination were reduced in intensity significantly by using NH3 as the reaction cell gas in the DRC. The detection limits were in the range of 0.1~0.5, 0.4~1.3 and 1.2~1.7 £gg/L for V, Cr and Fe, respectively. Applications of the method for the speciation of V, Cr and Fe in wastewater were demonstrated. The recoveries were in the range of 92~120% for various species. A capillary electrophoresis-inductively coupled plasma-mass spectrometric (CE-ICPMS) method for the speciation of six arsenic compounds, namely arsenite [As(III)], arsenate [As(V)], monomethyl arsonic acid, dimethylarsinic acid, arsenobetaine and arsenocholine is described. The separation has been achieved on a 70 cm length ¡Ñ 75 £gm ID fused-silica capillary. The electrophoretic buffer used was 15 mmol/L Tris (pH 9.0) containing 15 mmol/L sodium dodecyl sulfate (SDS), while the applied voltage was set at +22 kV. The arsenic species in biological tissues were extracted into 80% v/v methanol-water mixture, put in a closed centrifuge tube and kept in a water bath, using microwaves at 80¢J for 3 min. The extraction efficiencies of individual arsenic species added to the sample at 0.5 mg As/g level were between 96% and 107%, except for As(III), for which it was 89% and 77% for oyster and fish samples, respectively. The detection limits of the species studied were in the range 0.3~0.5 £gg As/L. The procedure has been applied for the speciation analysis of two reference materials, namely dogfish muscle tissue (NRCC DORM-2) and oyster tissue (NIST SRM 1566a), and two real-world samples.

Trace element composition of archaeological artifacts is commonly used for provenance studies. Limestone has generally studied by geologists and there are a few researches done by various archaeological sciences. Although it is a common material for buildings and sculpture it is been thought that limestone used had not imported like marbles. Limestone figurines from Dat&ccedil / a/Emecik excavations are classified as Cypriote type, which was very popular through 6th century B.C. in the Mediterranean region. Since this type of figurines was found at Emecik numerously to determine its provenance was an important problem. Emecik figurines were examined for their some major, trace elements and REE compositions and results were compared with geological samples which were taken from a near by quarry. Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), Inductively Coupled Plasma-Mass Spectrometry (ICPMS) have been used for analysis. The methods have been optimized by using standard reference material NIST 1d, NCS DC 73306, and IGS40.

Full wave analysis of microstrip lines at microwave frequencies is performed by using method of moments in conjunction with closed-form spatial domain Green&rsquo / s functions. The Green&rsquo / s functions are in general Sommerfeld-type integrals which are computationally expensive. To improve the efficiency of the technique, Green&rsquo / s functions are approximated by their closed-forms. Microstrip lines are excited by arbitrarily located current sources and are terminated by complex loads at both ends. Current distributions over microstrip lines are represented by rooftop basis functions. At first step, the current distribution over a single microstrip line is calculated. Next, the calculation of the current distributions over coupled microstrip lines is performed. The technique is then, applied to directional couplers. Using the current distributions obtained by the analysis, the scattering parameters of the structures are evaluated by using Prony&rsquo / s method. The results are compared with the ones gathered by using simulation software tools, CNL/2&trade / and Agilent Advanced Design System&trade / (ADS).

In this study, hydrogeological modeling of the Somme river basin situated in the north of France was made with special emphasis on the stream-aquifer interaction. The coupled model developed at Ecole des Mines de Paris was used. Geographic Information Systems (GIS) tools were incorporated during all the stages of modeling process for both preparation of input data and visualization of the results of simulations. Initially, the process began with Digital Elevation Model (DEM) analysis. Afterwards, the surface and aquifer grids were generated by using nested grid generators and refinement was made on the stream network and subcatchment boundaries in order to increase the accuracy of numerical solution. In order to run the surface model, meteorological forcing, land use and soil type data were acquired. Surface model was used to partition the precipitation into evapotranspiration, infiltration and surface runoff components. A steady-state piezometric head distribution was computed by the groundwater model to serve as an initial condition to the coupled model. The flow in the unsaturated zone was simulated by using Nash cascade model. The unsteady groundwater and surface flow simulations were performed by taking into consideration the stream-aquifer interaction on a daily time step. The calibration and validation were realized by using the streamflow and piezometric head measurements distributed around the basin. The strong groundwater influence on the hydrology of the basin is well represented by the model. Comparisons of predicted flooded areas in year 2001 were made with other models and a satellite derived image. In the end, several sensitivity analyses were performed for several parameters concerning the groundwater flow.

Reactions of singlet (1S and 1D) and triplet (3P) carbon atoms with water, and 1D and 3P carbon atoms with methanol were studied computationally. In the water and methanol systems, the carbon vapor containing a mixture of C(1S), C(1D), and C(3P) atoms, is predicted to react by primarily interacting with the oxygen, OH bond and CH bond of the substrate mainly with the 1D state. While C(1S) was proven to be unreactive C(3P) can hardly be supported to be reactive, and can safely be defined as unreactive. The major product, CO forms as a result of oxygen abstraction, which is observed as a fast, energetically quite favorable process. The scheme of this oxygen abstraction is promising to be applicable to substrates with the general formula R1-O-R2 i.e. water, alcohols, and ethers. OH insertion, both for water and methanol, yields trappable carbenes / the carbene being a key species on the distribution of the end products. Water matrix trapping the carbene opens the path to the formation of formaldehyde / and exhibits a prototype reaction for the formation of dialkoxymethanes. Gas phase product spectrum from the reactions are broader, due to the accessibility of the routes originating from the otherwise trapped intermediates / and the excess energy of the reactions being carried by them. In the condensed phase the very early and rapid reactions seem to have chance, the subsequent rearrangements are hard to occur. The conclusions thus far apply to the reactions in the gas phase as well as in condensed phases involving inert matrices / and the experimental isolation of the species is highly dependent on the ability of the medium to trap the intermediates via effective transfer of excess energy. Due to the large excess energies of intermediates involved, subsequent reactions are fast / of the order 1013 s-1 from kinetic rate calculations. In the absence of efficient transfer of non-fixed energies to the surrounding medium, all of the reaction paths will conclude with irreversible dissociation reactions. Plausible mechanisms for all the experimentally observed products are predicted. The results are in agreement with the available experimental data.

Combination of high strength with light weight which is the prominent property of aluminum alloy forgings has led aluminum forgings used in rapidly expanding range of applications. In this study, to produce a particular 7075 aluminum alloy part, the forging process has been designed and analyzed. The forging process sequence has been designed by using Finite Volume Method. Then, the designed process has been analyzed by using Finite Element Method and the stress, strain and temperature distributions within the dies have been determined. Five different initial temperatures of the billet / 438, 400, 350, 300 and 250 degree Celsius have been considered in the thermo-mechanically coupled simulations. The initial temperatures of the dies have been taken as 200 degree Celsius for all these analyses. Finite volume analysis and finite element analysis results of the preform and finish part have been compared for the initial billet temperature of 400 oC. Close results have been observed by these analyses. The experimental study has been carried out for the range of the initial billet temperatures of 251&amp / #8211 / 442 degree Celsius in METU-BILTIR Center Forging Research and Application Laboratory. It has been observed that the numerical and the experimental results are in good agreement and a successful forging process design has been achieved. For the initial die temperature of 200 degree Celsius, to avoid the plastic deformation of the dies and the incipient melting of the workpiece, 350 degree Celsius is determined to be the appropriate initial billet temperature for the forging of the particular part.

The purpose of this study is to determine the most suitable remediation technique via geotechnical assessment of the landslide that occurred during the construction of Bursa-ineg&ouml / l-Boz&uuml / y&uuml / k Road at KM: 72+000-72+200 in an ancient landslide area. For this purpose, the geotechnical parameters of the mobilized soil along the slide surface was determined by back analyses of the landslide at four profiles by utilizing the Slope/W software. The landslide was then modeled using coupled analyses (with the Seep/W and Slope/W softwares) along the most representative profile of the study area by considering the landslide mechanism, the parameters determined from the geotechnical investigations, the size of the landslide and the location of the slip circle. In addition, since the study area is located in a second degree earthquake hazard region, pseudo-static stability analyses using the Slope/W software were performed incorporating the earthquake potential. The most suitable slope remediation technique was determined to be a combination of surface and subsurface drainage, application of rock buttress at the toe of the slide and unloading of the landslide material. A static and dynamic analyses of the landslide was also performed through utilizing finite element analyses. The static analyses were calibrated using the inclinometer readings in the field. After obtaining a good agreement with the inclinometer readings and finite element analyses results, the dynamic analyses were performed using acceleration time histories, which were determined considering the seismic characteristics of the study area.