This study considers a symmetrical finite strip with a length of 2L and a width of 2h containing two collinear edge cracks located at the center of the strip. Each edge crack has a width h&amp / #8211 / a. Two ends of the finite strip are bonded to two rigid plates through which uniformly distributed axial tensile loads of intensity p0 are applied. The finite strip is assumed to be made of a linearly elastic and isotropic material. For the solution of the finite strip problem, an infinite strip of width 2h containing two internal cracks of width b&amp / #8211 / a at y=0 and two rigid inclusions of width 2c at y=&plusmn / L is considered. When the width of rigid inclusions approach the width of the strip, the portion of the infinite strip between the inclusions becomes identical with the finite strip problem. When the outer edges of the internal cracks approach the edge of the strip, they become edge cracks (notches). Governing equations are solved by using Fourier transform technique and these equations are reduced to a system of three singular integral equations. By using Gauss-Lobatto and Gauss-Jacobi integration formulas, these three singular integral equations are converted to a system of linear algebraic equations which is solved numerically.

Recent devastating earthquakes revealed that bridges are one of the most vulnerable components of the transportation systems. These seismic events have emphasized the need to mitigate the risk resulting from the failure of the bridges. Depending on the seismicity of the bridge local site, seismic vulnerability assessment of the bridges can be done based on the fragility curves. These curves are conditional probability functions which give the probability of a bridge attaining or exceeding a particular damage level for an earthquake of a given intensity level. In this dissertation, analytical fragility curves are developed for the ordinary highway bridges in Turkey constructed after the 1990s to be used in the assessment of their seismic vulnerability. Bridges are first grouped into certain major bridge classes based on their structural attributes and sample bridges are generated to account for the structural variability. Nonlinear response history analyses are conducted for each bridge sample with their detailed 3-D analytical models under different earthquake ground motions having varying seismic intensities. Several engineering demand parameters are employed in the determination of seismic response of the bridge components as well as defining damage limit states in terms of member capacities. Fragility curves are obtained from the probability of exceeding each specified damage limit state for each major bridge class. Skew and single-column bent bridges are found to be the most vulnerable ones in comparison with the other bridge classes. Developed fragility curves can be implemented in the seismic risk assessment packages for mitigation purposes.

Endocannabinoid and immune system alterations at moderate (18 m/min) and endurance (32 m/min) exercise intensities were assessed and compared to controls. Rats were exercised for 60 minutes/day, 5 days/week for 16 weeks. Immune effector cell proportions (T cell subtypes, B cells, NK cells, and neutrophils) and endocannabinoid serum levels were determined. Anandamide (ANA) and 2 arachidonyl-glycerol (2-AG) serum levels increased with endurance type of exercise. mRNA expression of the CB1 receptor increased together with ANA in the same group. Apoptotic index increased while immune effector cells responded divergently. B lymphocyte percentage decreased while T lymphocyte and NK cell percentage increased in blood. CD8+ subtypes increased whereas CD11b+ cell and CD25+ cell numbers decreased in the spleen in the endurance type of exercise group. Rats were grouped as the control, the endurance type of exercise, the AM281 (CB1 receptor antagonist) and the AM281+AM630 (CB2 receptor antagonist) groups in the second part of the study. Flow cytometry and microarray analyses of the spleen and the thymus were conducted. Endurance type of exercise associated significantly to immunological changes particularly to that of the T lymphocytes. T lymphocytes increased whereas cytolytic T lymphocytes decreased in blood. T cell and double positive T cell percentages significantly increased in the spleen. Activated T cells and NK like T cells furthermore decreased in the spleen. AM281 and/or AM630 could partially reverse the effect of exercise in blood but not in the spleen. Alterations in the thymus were not observed. Exercise altered 302 genes, some of them related with the immune system. Up-regulation of heat-shock protein coding genes was the most significant ones.

This thesis is aimed at identifying the noise sources of a wheeled tractor to reduce the noise levels below the legislative limits by controlling noise sources through proper methodologies. The study focuses firstly on identifying the noise sources of a wheeled tractor by using proper noise source identification techniques. These techniques can be summarized as sound intensity measurements, sound power level determination studies and spectral analysis of the noise data acquired in the tests. Simple sound intensity mapping techniques are used and the intensity contour maps are generated to identify the noise sources. Most important and effective noise sources are identified and the critical noise sources are focused to apply appropriate noise control strategies not only at the prototype production stages but also at the early design stages. Consequently, upon consideration of both structure-borne and flow-induced noise, the pass-by noise level and the operator&rsquo / s ear noise levels of the tractor are reduced by nearly 3 dB (A) through application of proper noise control strategies.

An axisymmetric finite cylinder with rigid ends and a circumferential edge crack is considered in this study. The finite cylinder is under the action of uniformly distributed loads at two rigid ends. Material of the finite cylinder is assumed to be linearly elastic and isotropic. This finite cylinder problem is solved by considering an infinite cylinder containing an internal ring-shaped crack located at z=0 plane and two penny-shaped rigid inclusions located at z=&plusmn / L planes. General expressions of the infinite cylinder problem are obtained by solving Navier equations with Fourier and Hankel transforms. This infinite cylinder problem is then converted to the target problem by letting the radius of the rigid inclusions approach the radius of the cylinder and letting the outer edge of the crack approach the surface of the cylinder. Consequently, these rigid inclusions form the rigid ends and internal crack form the circumferential edge crack resulting in the problem of a finite cylinder with rigid ends having an edge crack. The problem is reduced to a set of three singular integral equations. These singular integral equations are converted to a system of linear algebraic equations with the aid of Gauss-Lobatto and Gauss-Jacobi integration formulas and are solved numerically.

The present study aimed to investigate the fears of female and male children and adolescents between the ages of 8 and 18 from different socioeconomic levels. Additionally, the origins of children&rsquo / s and adolescents&rsquo / fears were examined. To reach the aims, the study was divided into two stages. In the first stage adaptation study of Fear Survey Schedule for Children-AM (Burnham, 1995) into Turkish was conducted. Two different samples were utilized in stage one. First sample was comprised of 355 participants (173 females and 182 males) with a mean age of 12.66 (SD=3.05). Second sample was comprised of 1315 participants (642 females and 673 males) with a mean age of 13.15 (SD=3.18). Second stage of the study was the main study. Second sample of the first stage including 1315 participants was utilized in stage two. Beside Fear Survey Schedule for Children, assessing the origins of children&rsquo / s and adolescents&rsquo / fears were utilized in the present study. Results of the study pointed that female children from low socioeconomic status at age 8 were the most fearful group among all children and adolescents. Also, for all fear factors female children and especially from low socioeconomic status reported higher level of fear than male preadolescents and adolescents. In general, it can be said that being female, from low socioeconomic status and young especially at age 8 is related to more intense fears. Among all children and adolescents, fears of children at age 8, 9 and 10 were significantly different than fears of preadolescents and adolescents at various ages, but they were not significantly different than each other. Fears of preadolescents at age 11, 12 and 13 were significantly different than preadolescents at least 2 years older than themselves. Overall most commonly endorsed fears were &ldquo / someone in my family dying&rdquo / , &ldquo / going to Hell&rdquo / , &ldquo / death of a closed person (grandparent, best friend etc.)&rdquo / , &ldquo / abuse&rdquo / , &ldquo / God&rdquo / , &ldquo / AIDS&rdquo / , &ldquo / someone in my family having an accident&rdquo / , &ldquo / my parents separating or getting divorced&rdquo / and &ldquo / terrorist attacks&rdquo / . Findings related to the origins of children&rsquo / s and adolescents&rsquo / fears indicated that 64.8% of all children learnt fear by modeling, 51.8% of all children learnt fear by negative information transmission and 35.8% all of children fear by experiences (conditioning). Negative information transmission intensified 45.7% of all children and adolescents, modeling intensified 49% of all children and adolescents and experience (conditioning) intensified 44.8% of all children and adolescents.

In the traditional analysis of acoustic wave propagation in an ocean waveguide, it's generally assumed that acoustic properties, including density and sound speed profile at seabed are taken to be constant. However, recent experimental data provided by Hamilton~(1980)~ have shown that the sediment layer in the seabed experiences a transitional change in which the density and the sound speed vary continuously from one value at the top to another at the bottom of the layer. The objective of this study is to investigate the surface-generated ambient noise in an isovelocity waveguide with a non-homogeneous fluid sediment layer. The noise model was first proposed by Kuperman and Ingenito~(1980) in the study of surface-generated ambient noise using normal mode approach, and the model proposed by Robins (1993) in the study of the sediment layer change in which the density and the sound speed vary continuously. It is demonstrated that the noise intensity may be affected by the stratification mainly through the continuous spectrum, in that the continuous spectrum is equally important as the normal modes in the present analysis. The continuous variation of the sediment layer reduces the contrast of the interface, which in turn affects the wavenumber spectrum, particularly in the continuous spectrum region. The results show that the horizontal correlation length of the noise field increases as that of the noise random sourse increase, but the vertical correlation length of the noise field decreases as that of the noise random sourse increase.

Bragg grating reflectors etched in amorphous silicon overlay films have been integrated with Ti:LiNbO3 optical waveguides. With a 12.5 mm long grating segment and an etch depth of ~ 93 nm in a 105 nm-thick silicon film, a narrow (0.05 nm) spectral bandwidth with a record high transmission dip (> 20 dB) was achieved at a wavelength of ~1542 nm for TE polarization on an x-cut, y-propagating substrate. The reflectance in the channel waveguides is found to be strongly dependent on the depth of the etched grating. The 3-dB bandwidth of 0.05 nm obtained for all tested samples is the smallest reported for waveguides in LiNbO3. The effect of the Bragg waveguide loss factor on the transmittance and reflectance spectra is investigated using a model for contra-directional coupling that includes an attenuation coefficient. The Bragg grating spectral characteristics are exploited to fabricate distributed Bragg feedback modulators (DBFM) and Bragg reflector Fabry-Perot modulators (BFPM). The sharp cut-off in transmission and reflection spectra, which is an inherent characteristic of Bragg grating, was tuned by applying voltage via the linear electrooptic effect, to produce intensity modulation. The Bragg grating based modulators consume less electric power compared to polarization intensity modulators (PIMs). The DBFM demonstrates 1/1.6 times the modulating voltage of a PIM with identical waveguide and electrode structure. The BFPM shows 1/3.3 times the modulating voltage of the PIM. No difference in the frequency response is observed among the three modulators. Comparison of the modulation sensitivity in the linear region indicates that the Bragg grating based modulators provide better sensitivity than that of the PIM with identical waveguide and electrode structure. These results indicate the potential advantage of the Bragg grating based modulators for enhanced modulation efficiency over conventional modulators. Further improvements can be expected from the optimization of the electrode design.

The internal tide in GPSC¡]Gaoping submarine canyon¡^is the main factor controlling the movement of watermasses. In order to improve our understanding on the compact of suspended sediment exchange in and out GPSC, the data used in this study are collected from four cruises of field observations using research vessel OR3. Instruments deployed include ADCPs¡BEK500¡BCTD and vertical string of temperature loggers. The collected data are analyzed through a variety of time series analysis technique, such as harmonic analysis¡BFFT and EOF. The results show that¡]1¡^the echo intensity recorded by ADCP through calibration could reduce the decay of echo with the distance. The results seem useful to apply in watermass behavior studies.¡]2¡^ Echo intensity with calibration were comparable with signal recorded by EK500 which could be validated to each other. These observations were related to sediment resuspension influenced by internal tide. ¡]3¡^There were two layers of large turbidity, at the depth of canyon edge and near the bottom of canyon, both were fluctuated with two interval tidal frequency.¡]4¡^Another band of echo intensity fluctuations, not directly correlate to sediment resuspension, was likely due to vertical migration, of zooplankton or biology effects.

<p> </p><p> </p><p>According to the Environmental Kuznets Curve (EKC), economic growth will eventually cause carbon dioxide emissions to decrease. Is this the case in Sweden? A time series covering the period 1800-1995 is used to analyze the relation between carbon dioxide emissions and income per capita in Sweden. The empirical results indicate that an EKC for carbon dioxide is highly likely to exist in Sweden for the examined period. To take the analysis further, a cross-section data set is employed to examine the relationship between carbon dioxide emissions, income per capita and 4 other potentially influential variables in 75 countries. Only carbon intensity of energy is significant for carbon dioxide emissions. This implies that the utilized energy source is of importance, and it is crucial to separate energy consumption from carbon dioxide emissions. Emissions is a matter of structural aspects such as the type of industry and production a country comprise, and what type of energy that is consumed; not merely the quantity of energy. Sweden has experienced a shift in production techniques and in energy supply, and the energy-efficiency has improved during the past 100 years. It is consequently plausible to believe that it is not a critical income per capita which decreases CO</p><p>2  emissions – it is the “right” energy sources, energy efficiency and improved technology.</p><p> </p><p> </p>