Based on the linear relationship between concentration of H2O2 and the decrease of electrochemiluminescence (ECL) intensity in a Ru(bpy)32+/TPA system, procedures for the indirect determination of glucose with a flow injection analysis were developed. By passing solutions of glucose through a FIA system containing a glucose oxidase (GOx) immobilized sol-gel column and an ECL system of Ru(bpy)32+ and TPA, glucose can be determined optimally with a detection limit of 1.0 £gM in a linear dynamic range of 1.0 ¡V 200.0 £gM. A repetitive injection of glucose (100 £gM) and human serum solutions gave satisfactory reproducibility with relative standard deviations of 1.3 (N=31) and 3.9 % (N=42) respectively. Interference due to the presence of ascorbic acid, uric acid or other reducible agents in solution can be corrected by passing sample solutions through another sol-gel column that contained no GOx. From the agreement between the contents of glucose in human serum and soft drink analyzed by the developed method and those obtained by the spectroscopy method based glucose assay kit and satisfactory recovery of glucose from interferent containing solutions, the feasibility of the developed method for real sample analysis was confirmed. One of the major purposes of this study was to develop new immobilization approaches and flow cell designs for the fabrication of regenerable ECL-based sensors with improved sensitivity, convenience and long-term stability. Silica particulates were used as immobilization support in ECL sensors for TPA and NAD(P)H and in biosensors for glucose and glucose-6-phosphate¡]G6P¡^. The first ECL flow cell was fabricated from a glass tube, and a platinum wire was used as working electrode held at +1.3 V. The volume of the flow cell was about 50 £gL. An Ag/AgCl electrode and a piece of Pt wire were used as the reference and counter electrode respectively and placed downstream of the working electrode. Ru(bpy)32+ immobilized silica particulates with 1/3 silica sol content showed the best performance for TPA determination, and the sensitivity of TPA determination was dependent upon the amount of Ru(bpy)32+ immobilized in silica particulates. The lowest level of analyte detected for TPA was 0.02£gM, and linear range was from 0.02£gM to 5£gM. Up to a certain concentration level, it was found that Ru(bpy)32+ was tightly held in silica particulates and did not leach out into aqueous solutions, even with continuous flow for up to ten hours. Ru(bpy)32+ immobilized silica particulates were characterized of well activity and high stability; that stored at 0¢J exhibited its original activity for up to one year. The second ECL flow cell was fabricated from a piece of epoxy block supported Pt electrode (1 ¡Ñ 2 cm) as counter electrode, a piece glass window and a polyethylene spacer with 78 £gL cell volume, two 2.0-cm length of 0.6-mm diameter platinum wires were used as working electrodes held at +1.1 V, and an Ag/AgCl electrode as reference electrode. All three electrodes were incorporated within the main body of the cell. One of the biosensor design packed Ru(bpy)32+ incorporated silica particulates in the ECL flow cell, and a glucose dehydrogenase (GDH) immobilized silica sol-gel column is placed between the sample injection valve and the flow cell. The ECL response to samples containing glucose and cofactor (NADP) results from the Ru(bpy)33+ ECL reaction with NADPH produced by glucose dehydrogenase. This ECL biosensor was shown applicable for both NAD+- and NADP+- dependent enzymes, where NADH detection ranged from 0.50£gM ¡V 5.0 mM NADH and NADPH detection ranged from 1.0£gM - 3.0 mM NADPH. Glucose can be determined in a linear dynamic range of 5.0 - 500 £gM. Another biosensor design immobilized glucose-6-phosphate dehydrogenase¡]G6PDH¡^onto the Ru(bpy)32+ -doped silica particulates through silica chemistry and then packed these particulates into the ECL flow cell. By passing samples containing G6P and cofactor (NAD) through the ECL flow cell, G6P can be determined in a linear dynamic range of 10.0 £gM-1.0 mM. The regenerable ECL biosensor was characterized of good reproducibility and well stability for flow injection analysis. A repetitive injection of NADH (100 £gM) and G6P¡]500£gM¡^gave satisfactory reproducibility with relative standard deviations of 2.8 %¡]N=105¡^and 2.8 % (N=40) respectively.

Effects of a magnetic field on the double-probe technique are studied experimentally by means of symmetric floating computer controlled fast double probes in low and intermediate pressure plasmas. In addition, the effects of the magnetic field on the electron temperature, electron density, and electric field have been investigated. As it is expected, when there is no magnetic field, properties of the discharge plasma are best described by Langmuir theory. Whereas, when there&rsquo / s a magnetic field of sufficient strength Schottky&rsquo / s theory of ambipolar diffusion applies.

Deterioration in the mechanical properties of concrete, masonry and steel structures are usually observed under repeated cyclic loading in the inelastic response range. Therefore such a behavior becomes critical when these types of structures are subjected to ground motions with specific characteristics. The objective of this study is to address the influence of degrading behavior on simple systems. The Structural Performance Database on the PEER web site, which contains the results of cyclic, lateral-load tests of reinforced concrete columns, are employed to quantify the degradation characteristics of simple systems by calibrating the selected degrading model parameters for unloading stiffness, strength and pinching of a previously developed hysteresis model. The obtained values of parameters from cyclic test results are compared with the recommended values in literature. In the last part of the study, response of SDOF systems with various degradation characteristics are investigated using a set of seismic excitations recorded during some major earthquakes. The results indicate that when all the degradation components are combined in a structural system, the effect of degradation on response values becomes much more pronounced.

Modeling and inferential control studies are carried out on a reactive batch distillation system for the esterification reaction of ethanol with acetic acid to produce ethyl acetate. A dynamic model is developed based on a previous study done on a batch distillation column. The column is modified for a reactive system where Artificial Neural Network Estimator is used instead of Extended Kalman Filter for the estimation of compositions of polar compounds for control purposes. The results of the developed dynamic model of the column is verified theoretically with the results of a similar study. Also, in order to check the model experimentally, a lab scale column (40 cm height, 5 cm inner diameter with 8 trays) is used and it is found that experimental data is not in good agreement with the models&rsquo / . Therefore, the model developed is improved by using different rate expressions and thermodynamic models (fi-fi, combination of equations of state (EOS) and excess Gibbs free energy (EOS-Gex), gama-fi) with different equations of states (Peng Robinson (PR) / Peng Robinson - Stryjek-Vera (PRSV)), mixing rules (van der Waals / Huron Vidal (HV) / Huron Vidal Original (HVO) / Orbey Sandler Modification of HVO (HVOS)) and activity coefficient models (NRTL / Wilson / UNIQUAC). The gama-fi method with PR-EOS together with van der Waals mixing rule and NRTL activity coefficient model is selected as the best relationships which fits the experimental data. The thermodynamic models / EOS, mixing rules and activity coefficient models, all are found to have very crucial roles in modeling studies. A nonlinear optimization problem is also carried out to find the optimal operation of the distillation column for an optimal reflux ratio profile where the maximization of the capacity factor is selected as the objective function. In control studies, to operate the distillation system with the optimal reflux ratio profile, a control system is designed with an Artificial Neural Network (ANN) Estimator which is used to predict the product composition values of the system from temperature measurements. The network used is an Elman network with two hidden layers. The performance of the designed network is tested first in open-loop and then in closed-loop in a feedback inferential control algorithm. It is found that, the control of the product compositions with the help of an ANN estimator with error refinement can be done considering optimal reflux ratio profile.

This study uses a 3D finite element program, calibrated with the results of a full scale instrumented load test on a limited size footing, to estimate the settlement improvement factor for footings resting on rammed aggregate pier groups. A simplified 3D finite element model (Composite Soil Model) was developed, which takes into account the increase of stiffness around the piers during the ramming process. Design charts for settlement improvement factors of square footings of different sizes (B = 2.4m to 4.8m) resting on aggregate pier groups of different area ratios (AR = 0.087 to 0.349), pier moduli (Ecolumn = 36MPa to 72MPa), and with various compressible clay layer strengths (cu = 20kPa to 60kPa) and thicknesses (L = 5m to 15m) were prepared using this calibrated 3D finite element model. It was found that, the settlement improvement factor increases as the area ratio, pier modulus and footing pressure increase. On the other hand, the settlement improvement factor is observed to decrease as the undrained shear strength and thickness of compressible clay and footing size increase. After using the model to study the behaviour of floating piers, it was concluded that, the advantage of using end bearing piers instead of floating piers for reducing settlements increases as the area ratio of piers increases, the elasticity modulus value of the piers increases, the thickness of the compressible clay layer decreases and the undrained shear strength of the compressible clay decreases.

The main objective of the thesis is evaluating and comparing Second-Order Elastic Analysis Methods defined in two different specifications, AISC 2005 and TS648 (1980). There are many theoretical approaches that can provide exact solution for the problem. However, approximate methods are still needed for design purposes. Simple formulations for code applications were developed, and they are valid as acceptable results can be obtained within admissible error limits. Within the content of the thesis, firstly background information related to second-order effects will be presented. The emphasis will be on the definition of geometric non-linearity, also called as P-&amp / #948 / and P-&amp / #916 / effects. In addition, the approximate methods defined in AISC 2005 (B1 &ndash / B2 Method), and TS648 (1980) will be discussed in detail. Then, example problems will be solved for the demonstration of theoretical formulations for members with and without end translation cases. Also, the results obtained from the structural analysis software, SAP2000, will be compared with the results acquired from the exact and the approximate methods. Finally, conclusions related to the study will be stated.

Prior studies indicated that beam-to-column connections of reinforced concrete (RC) moment resisting frame structures experience considerable deformations under earthquake loading and these deformations have a major contribution to story drift of the building. In current analysis and design applications, however, the connection regions are generally modeled as rigid zones and the inelastic behavior of the joint is not taken into account. This assumption gives rise to an underestimation of the story drifts and hence to an improper assessment of the seismic performance of the structure. In order to implement the effect of these regions into the seismic design and analysis of buildings, a model that properly represents the seismic behavior of connection regions needs to be developed. In this study, a parametric model which predicts the joint shear strength versus strain relationship is generated by investigating the several prior experimental studies on RC beam-to-column connections subjected to cyclic loading and establishing an extensive database. Considering previous experimental research and employing statistical correlation method, parameters that significantly influence the joint behavior are determined and these parameters are combined together to form a joint model. This model is then verified by comparing the results obtained from the dynamic earthquake analysis by Perform 3D with the experimental ones. The main contribution of the developed model is taking into account parameters like the effect of eccentricity, column axial load, slab, wide beams and transverse beams on the seismic behavior of the connection region, besides the key parameters such as concrete compressive strength, reinforcement yield strength, joint width and joint transverse reinforcement ratio.

Current seismic design approach of bridge structures can be categorized into two distinctive methods: (i) force based and (ii) performance based. AASHTO LRFD seismic design specification is a typical example of force based design approach especially used in Turkey. Three different importance categories are presented as &ldquo / Critical Bridges&rdquo / , &ldquo / Essential Bridges&rdquo / and &ldquo / Other Bridges&rdquo / in AASHTO LRFD. These classifications are mainly based on the serviceability requirement of bridges after a design earthquake. The bridge&rsquo / s overall performance during a given seismic event cannot be clearly described. Serviceability requirements specified for a given importance category are assumed to be assured by using different response modification factors. Although response modification factor is directly related with strength provided to resisting column, it might be correlated with selected performance levels including different engineering response measures. Within the scope of this study, 27216 single circular bridge column bent models designed according to AASHTO LRFD and having varying column aspect ratio, column diameter, axial load ratio, response modification factor and elastic design spectrum data are investigated through a series of analyses such as response spectrum analysis and push-over analysis. Three performance levels such as &ldquo / Fully Functional&rdquo / , &ldquo / Operational&rdquo / and &ldquo / Delayed Operational&rdquo / are defined in which their criteria are selected in terms of column drift measure corresponding to several damage states obtained from column tests. Using the results of analyses, performance categorization of single bridge column bents is conducted. Seismic responses of investigated cases are identified with several measures such as capacity over inelastic demand displacement and response modification factor.

Due to their practical application, flat-plates have been commonly used slab type in constructions in recent years. According to the investigations that were performed since the beginning of the 20th century, the vicinity of the slab-column connection is found to be susceptible to punching failure that causes serious unrepairable damage leading to the collapse of the structures. The objective of this study is to enhance the punching shear strength of slab-column connections in existing deficient flat plate structures. For this purpose, an economical and easy to install strengthening method was applied to &frac34 / scale flat-slab test specimens. The proposed strengthening scheme employs the use of in house-fabricated Carbon Fiber Reinforced Polymer (CFRP) dowels placed around the column stubs in different numbers and arrangements as vertical shear reinforcement. In addition, the effect of column aspect ratio on strengthening method was also investigated in the scope of this study. Strength increase of at least 30% was obtained for the CFRP retrofitted specimens compared to the companion reference specimen. Three-dimensional finite element analyses of test specimens were conducted by using the general purpose finite element analyses program. 3-D finite element models are successful in providing reasonable estimates of load-deformation behavior and strains. The experimental punching shear capacities and observed failure modes of the specimens were compared with the estimations of strength and failure modes given by punching shear strength provisions of ACI 318-08, Eurocode-2, BS8110-97 and TS500. Necessary modifications were proposed for the existing provisions of punching shear capacity in order to design CFRP upgrading.

Liquefiable soils are common at ports due to the use of hydraulic fills for construction of waterfront facilities. Liquefaction-induced ground failure can result in permanent ground deformations that can cause loss of foundation support and structural damage. This can lead to substantial repair and/or replacement costs and business interruption losses that can have an adverse effect on the port and the surrounding community. Although numerous soil improvement methods exist for remediating a liquefaction-prone site, many of these methods are poorly suited for developed sites because they could damage existing infrastructure and disrupt port operations. An alternative is to use a passive remediation technique. Treating liquefiable soils with colloidal silica gel via permeation grouting has been shown to resist cyclic deformations and is a candidate to be used as a soil stabilizer in passive mitigation. The small-strain dynamic properties are essential to determine the response to seismic loading. The small-to-intermediate strain shear modulus and damping ratio of loose sand treated with colloidal silica gel was investigated and the influence of colloidal silica concentration was determined. The effect of introducing colloidal silica gel into the pore space in the initial phase of treatment results in a 10% to 12% increase in the small-strain shear modulus, depending on colloidal silica concentration. The modulus reduction curve indicates that treatment does not affect the linear threshold shear strain, however the treated samples reduce at a greater rate than the untreated samples in the intermediate-strain range above 0.01% cyclic shear strain. It was observed that the treated sand has slightly higher damping ratio in the small-strain range; however, at cyclic shear strains around 0.003% the trend reverses and the untreated sand begins to have higher damping ratio. Due to the nature of the colloidal silica gelation process, chemical bonds continue to form with time, thus the effect of aging on the dynamic properties is important. A parametric study was performed to investigate the influence of gel time on the increase in small-strain shear modulus. The effect of aging increases the small-strain shear modulus after gelling by 200 to 300% for the 40-minute-gel time samples with a distance from gelation (time after gelation normalized by gel time) of 1000 to 2000; 700% for the 2-hour-gel time sample with a distance from gelation of 1000; and 200 to 400% for the 20-hour-gel time samples with a distance from gelation of 40 to 100. The treatment of all potentially liquefiable soil at port facilities with colloidal silica would be cost prohibitive. Identifying treatment zones that would reduce the lateral pressure and resulting pile bending moments and displacements caused by liquefaction-induced lateral spreading to prevent foundation damage is an economic alternative. Colloidal silica gel treatment zones of varying size and location were evaluated by subjecting a 3-by-3 pile group in gently sloping liquefiable ground to 1-g shaking table tests. The results are compared to an untreated sample. The use of a colloidal silica treatment zone upslope of the pile group results in reduced maximum bending moments and pile displacements in the downslope row of piles when compared to an untreated sample; the presence of the treatment zone had minimal effect on the other rows of piles within the group.