When patients move during an MRI examination, severe artifacts arise in the reconstructed image and motion correction is therefore often desired. An in-plane motion correction algorithm suitable for PRESTO-CAN, a new 3D functional MRI method where sampling of k-space is radial in kx-direction and kz-direction and Cartesian in ky-direction, was implemented in this thesis work. Rotation and translation movements can be estimated and corrected for sepa- rately since the magnitude of the data is only affected by the rotation. The data were sampled in a radial pattern and the rotation was estimated by finding the translation in angular direction using circular correlation. Correlation was also used when finding the translation in x-direction and z-direction. The motion correction algorithm was evaluated on computer simulated data, the motion was detected and corrected for, and this resulted in images with greatly reduced artifacts due to patient movements. / När patienter rör sig under en MRI-undersökning uppstår artefakter i den rekonstruerande bilden och därför är det önskvärt med rörelsekorrigering. En 2D- rörelsekorrigeringsalgoritm som är anpassad för PRESTO-CAN har tagits fram. PRESTO-CAN är en ny fMRI-metod för 3D där samplingen av k-rummet är radiell i (kx,kz)-planet och kartesisk i ky-riktningen. Rotations- och translationsrörelser kan estimeras separat då magnituden av signalen bara påverkas av rotationsrörelser. Eftersom data är samplat radiellt kan rotationen estimeras genom att hitta translationen i vinkelled med hjälp av cirkulär korrelation. Korrelation används även för att hitta translationen i i x- och z-riktningen. Test på simulerat data visar att rörelsekorrigeringsalgoritmen både detekterar och korrigerar för rörelser vilket leder till bilder med mycket mindre rörelseartefakter.

At the moment Swedish Transport Administration uses a monitor system that candetect urgent errors as warm ball-bearings and flat wheels etc. with stationarydetectors. To avoid these errors Swedish Transport Administration, UPWIS AB andUppsala University work with a system that will continuously monitoring the train todetect the errors as fast as possible. This will save money in the future for SwedishTransport Administration and all other partners that use the rails.Swedish Transport Administration has already RFID readers beside the rail to detecttrains position. The new monitoring system will use these readers and send data fromthe monitoring system via these readers to a database.The aim of this thesis work is to design and build a RFID antenna to send data fromthe monitoring system to the RFID readers. The antenna should be a circularpolarized and it needs to manage the harsh environment on the train.This thesis work started with a theoretical study which investigated four commonantenna types (dipole, loop, PIFA and patch/microstrip) to evaluate which antennatype that is the best solution for this application. It was decided to design a patchantenna from the theoretical study since it fulfils all the requirements for the antenna.Simulations and tests shows that the antenna is circular polarized and have amaximum reading distance of 5 m for 868 MHz. For 2.45 GHz it is linear polarizedand has a reading distance of at least 10 m. With other hardware settings the antennawill have longer reading distance at 2.45 GHz.When all parts of the test bed was finished the test bed was mounted on themeasurement wagon. The final test shows that the antenna fulfils the task. Theantenna transmitted the data from the sensor boxes to the RFID readers.The report suggests future work to minimize the reading distance and size for theantenna. These are: transfer sensor data to RFID tag by “multi hop”, hardwareimprovement for instance antenna diversity and using another substrate (higherdielectric constant).

The polarization behaviour for six species of Scarab beetles from the Chrysina genus is investigated with Mueller Matrix Spectroscopic Ellipsometer (MMSE). The m41 element of the matrix, which is related to the circular polarization behaviour, is analysed. The ellipticity, degree of polarization and azimuth angle are also presented to get a better understanding of the polarization effect. The measurements were done with a dual rotating compensator ellipsometer. The measured wavelength region was from 240 to 1000 nm and the angle of incidence from 25° to 75° in most of the cases. In general very high ellipticities (near circular) are reported. All specimens studied reflect both right- and left-handed polarized light. Depending on the species, two general types of polarization behaviour were observed. Chrysina macropus and Chrysina peruviana showed m41 values close to 0. Green stripes on Chrysina gloriosa showed similar polarization behaviour whereas gold stripes on the same beetle had much more pronounced m41 variations. Large m41 variations were also observed for Chrysina argenteola, Chrysina chrysargyrea and Chrysina resplendens. Four specimens of Chrysina resplendens show different m41 patterns suggesting differences in their structures.

Light reflected from the scarab beetles Cetonia aurata (C. aurata) and Chrysina gloriosa (C. gloriosa) has left-handed polarization. In this work the polarizing properties and structural characteristics of the cuticles of these two beetles are investigated with two different techniques: scanning electron microscopy (SEM) and Mueller-matrix spectroscopic ellipsometry (MMSE). SEM is used to get cross section images of the epicutucle and the endocuticle. Thicknesses around 18 μm were measured for both layers for C. aurata and between 12 and 16 μm for C. gloriosa. A layered structure is observed in both beetles. In addition, a cusp-like structure is also observed in C. gloriosa. MMSE showed left-handed near-circular polarization of light reflected on both beetles. For C. aurata this is observed in a narrow wavelength range (500-600 nm) and for C. gloriosa in a wider wavelength range (400-700 nm) when measured on golden areas of the cuticle. C. gloriosa also has green areas where the reflected light was linearly polarized. The results are used in regression modelling. A good model approximation was found for C. aurata for angles up to 60 whereas a good starting point for future work was reached for C. gloriosa.

This thesis presents a study of the effects of deep excavations on adjacent metro or utility tunnel in soft to medium soil. The main objective of the thesis is to develop a method of estimating these effects quantitatively. Extensive review of relevant literature published in the past four decades was conducted in order to understand the trends and the key developments in this area. It was revealed from the literature review that the concurrent use of the Observational Method and the finite element method for monitoring and controlling of ground deformations around the excavation has become a norm for deep excavation projects. Several design charts and guidelines for estimation of effects of deep excavations on adjacent raft foundations or pile foundations were found in the literature; however, no such charts or guidelines were found for estimation of effects of deep excavations on existing circular tunnels. Consequently, the development of these guidelines was established as one of the objectives of this study. <p>The initial phase of the research was focused on detailed study and analysis of two well-documented case studies the Chicago Subway Renovation Project, USA and the Tan Tock Seng Hospital Deep Excavation, Singapore. The back analyses of these two case studies were carried out using the finite element software PLAXIS. Exact site conditions and input parameters for the soil and the structural components were incorporated as much as possible. Appropriate adjustments in some of the input parameters were necessary to achieve good match between the computed and the observed results. <p> The back analyses were followed by parametric studies to identify important variables controlling the mechanisms of soil-structure interaction. The variables identified from the parametric studies of the two case studies were: soil stiffness, tunnel lining thickness, the depth of the excavation, and the location of tunnel. These variables were used to conduct a series of finite element analyses using simplified geometry and ground conditions for the purpose of formulating preliminary design charts. Results from these analyses were recorded in terms of in-plane and out-of-plane distortion of tunnel lining as well as additional shear forces and bending moments induced in the tunnel lining due to an adjacent deep excavation. The results were made non-dimensional before presenting them as contour plots. These contour plots constitute preliminary design charts, which can be used for the estimation of tunnel lining deformation caused by adjacent deep excavation.<p> Based on the results of this study, it can be concluded that a finite element program (such as PLAXIS) that is able to model construction processes associated with tunnelling and deep excavation in urban environment can be an invaluable tool in exploring the mechanism of ground deformation around the deep excavation and in quantifying the effects of ground deformation on existing adjacent structures. The modeller must, however, be aware of the fact that ways of modelling a particular construction process could be different for various finite element programs. It is important to interpret the instructions given in the manual of the program correctly. <p>Detailed back analyses of well-documented deep excavation case histories are vital from the point-of-view of building confidence in the selected finite element program. Such analyses also have the potential to identify key variables influencing the soil-structure interaction. <p> Preliminary design charts proposed in this thesis are very convenient for obtaining approximate values of tunnel lining deformation caused by adjacent deep excavation. Non-dimensional nature of these design charts makes it possible to be used for any depth of the deep excavation and for tunnels of any size, depth of cover, and distance from the vertical face of the excavation. These design charts can be used by engineers and contractors for initial estimation, selection and preliminary design of excavation support system, and are particularly useful during the planning phase. Town planners and project managers, who need to decide on the feasibility, damage control and risk management aspects of a deep excavation project, may also find these design charts equally useful. It should, however, be kept in mind that the estimates obtained from these design charts are highly approximate and as such, should be taken as guidelines for decision making processes. These estimates do not replace site specific detailed analysis and monitoring.

Due to the complexity of electro-elastic coupling characteristics in piezoelectric material, some of the elastic, dielectric and piezoelectric parameters are difficult to be measured. Usually, these parameters are determined by assuming that all offer parameters are remained constant during the measurement. However, the interactive effect between material properties makes this assumption be not always true. In this study, the measured natural frequencies of the specified circular piezoelectric plate are used to extract these parameters simultaneously. In other words, all these parameters are determined with considering the interactive electro-elastic coupling effect. The analytic model of free-free circular piezoceramic plate was derived and solved to establish the relationship between natural frequencies and its material parameters, to cover most all the parameters, the out-of-plane(non-symmetric transverse) and in-plane(symmetric extensional) modes are considered. The genetic algorithm is employed to determine most all elastic, dielectric and piezoelectric parameters from a least square error between the calculated and measured natural frequencies. Numerical results derived from the parameters proposed in this work reveal a good agreement with the measured data. In other words, the proposed method to extract the piezoelectric parameters is feasible and effective.

In order to investigate the effects of C-terminus modification of Dragon Grouper Nervous Necrosis Virus capsid protein on the virus particle formation, we used E. coli expression system to express DGNNV capsid protain with different truncations at C-teminus fused with six or three histidines (His-Tag). These poly-His tagged clones, including ¡µC334-C6H, ¡µC335-C6H, ¡µC336-C6H, ¡µC337-C6H, C3H and C6H (His6 tagged at the C-teminus of wild-type capsid protein)¡Awere expressed and VLPs formation ability were examined. Wild-type and N-terminal recombination (N6H, His6 tagged at the N-teminus of wild-type capsid protein) were also used for comparison. These His-tagged VLPs can be further purified by Ni-NTA agarose, and their thermal stability of mutant VLPs were analyzed by Circular Dichroism. The Western blotting and ELISA assay were utilized to analyzed N-teminus or C-terminus was located at the surface of virus icosahedron. Once the four amino acids at the C-terminus of capsid protein were truncated (¡µC334-C6H), the mutated cpasid protein cannot assemble into VLPs. The same phenomenon was also observed in C6H. The related productions of wild-type, ¡µC335-C6H, ¡µC336-C6H, ¡µC337-C6H, C3H VLPs were about 100%, 56%, 116%, 141%, and 193%, respectively. Using Circular Dichroism to observe the thermal stability of mutant VLPs, the results revealed that the Tm of mutant VLPs were about 3oC lower than wild-type VLPs (61oC). The results of Western blotting and ELISA assay suggest that the C-termius of DGNNV capisid protein was exposed to the surface of virus structure.

The present work seeks to investigate the thermal hydraulic (heat transfer and fluid dynamics) behavior of supercritical (Sc) fluids at both the fundamental and applied levels. The thermal hydraulics of these fluids is not very well known although they have been used in various applications. There are drastic changes in the thermal and hydraulic properties of fluids at supercritical conditions. There has been a lot of focus to effectively utilize these properties changes in many applications such as heat exchangers. This work focuses on studying the forced convective heat transfer of Sc-CO2 in a series of mini semi-circular horizontal tubes and a zig-zag shaped horizontal channel. The problems were investigated numerically by second-order finite volume method using a commercial software FLUENT. Three dimensional Computational Fluid Dynamics (CFD) models were developed to simulate the flow and heat transfer for three different geometries – a single semi-circular channel, a series of nine parallel semi-circular channels and a zig-zag channel. Grid and accuracy refinement studies were carried out to assess numerical errors. All the computational meshes developed for this study incorporated the first node cell within the viscous sub-layer i.e. y <1. Since the flow is turbulent, an appropriate choice of turbulence model is highly desirable. Henceforth, various turbulence models were used to study their impact on the heat transfer solution for these problems. The present numerical work focuses on improving the CFD model and methodologies in order to capture the experimental data of the heat transfer spike at the super critical conditions. Local and average heat transfer coefficients near the critical point were determined from measured wall temperatures and calculated local bulk temperatures. The numerical results are compared with the experiments. The numerical predictions do not convincingly agree with the experiments. This could be because of the incapability of turbulent models to capture the flow physics accurately due to the rapid changes in the fluid properties near critical conditions.

In the present study, circular cylinders in the cross-flow or the motions of circular cylinders in a fluid at rest are especially of interest in fields, such as offshore and civil engineering or heat exchanger. For last two decades, the researches of the force caused by the fluid on the cylinder surface are mainly studied by the ways of experiment and numerical methods. A time-independent finite different method is developed to solve the two-dimensional fixed or transversely oscillating cylinder passing by a cross flow. The present study focuses on the cylinder under a cross flow with only two kinds of conditions, which are Re = 100, KC = 5 and Re=200, KC=4. The benchmark tests of the present numerical results are made and validated by the reported numerical simulation and experimental results, for instant, the flow visualization of the vorticity contours and the in-line force for a flow across a moving circular cylinder. The developed numerical method can easily apply on the analyses of interactions between viscous flow and motion cylinder. Besides, we also consider the oscillatory flow passes a circular cylinder connecting with a spring. The spring -linking cylinder is released in the beginning on the position of zero deflection of the spring and stares moving due to the influence of the in-line force acting on the cylinder. We can find that the spring-linking cylinder under a oscillating flow produces restoring force and drag force due to considering the influence of the spring and damping effect, the developed numerical method can easily apply on the analyses of interactions between viscous flow and oscillating cylinder.

The atomization problem of high speed viscous jets has many applications in industrial processes and machines. In all these applications, it is required that the droplets have high surface area/volume ratio meaning that the droplets should be as small as possible. This can be achieved with high rates of turbulence and mixing of the flow. In order to constitute a foresight of geometry eects on droplet size, experimental investigation and the determination of flow characteristics in near and far fields of a low-speed air jet have been performed. In order to fulfill this task, three components of instantaneous velocity are measured, using a triple sensor Constant Temperature Anemometer (CTA) system. Through these measurements, mean velocity, Reynolds stress, velocity decay, spreading rate, turbulent kinetic energy, vorticity, and mass entrainment rate values are obtained. Stress-Strain relationship is also observed. Measurements are obtained for a baseline circular nozzle (round jet) as well as for an equilateral triangular and a square nozzle. On the basis of these measurements, the equilateral triangular jet is found to be the best option in order to get highest turbulence and mixing level with smallest core length.