Thèses sur le sujet « Deformation assessment »

Multilayer embedded passives (resistors, inductors, and capacitors) on a printed wiring board can help to meet high performance requirements at a low cost and at a smaller size. Such an integration of embedded passives has new challenges with respect to design, materials, manufacturing, thermal management and reliability. As the area of integral passives on printed circuit boards is relatively new, there is inadequate literature on the thermo-mechanical reliability of integral passives. Therefore, there is a compelling need to understand the thermo-mechanical reliability of integral passives through the development of physics-based models as well as through experiments, and this thesis aims to develop such an experimental and theoretical program to study the thermo-mechanical reliability of integral passives.. As integral passives are often composite layers with dissimilar material properties compared to the other layers in the integral substrate, it is essential to ensure that RLC characteristics of the embedded passives do not deteriorate with thermal cycling due to thermo-mechanical deformations. This thesis aims to study the changes in the passive characteristics due to the thermally-induced deformations. Embedded capacitors and inductors have been looked at specifically in this research. Multi-field physics-based models have been constructed to determine the change in electrical parameters after thermal cycling. The thermo-mechanical models assume direction-dependent material properties for the board substrate and interconnect copper layers and temperature-dependent properties for interlayer dielectric and passive layers. Using the deformed geometry, the electrical characteristics have been determined at low frequency. In parallel to the models, test vehicle substrates have been subjected to 1000 thermal cycles between -55??o 125??nd high humidity and temperature conditions at 85??5RH for 500 hours, and it has been observed that there are significant changes in the electrical parameters. The results obtained from the physics-based simulations have been validated against the measured electrical characteristics from the fabricated functional test boards that have been thermal cycled.

Abstract : The present study addressed the feasibility of reinforced-concrete squat walls totally reinforced with GFRP bars to attain reasonable strength and drift requirements as specified in different codes. Nine large-scale squat walls with aspect ratio (height to length ratio) of 1.33—one reinforced with steel bars (as reference specimen) and eight totally reinforced with GFRP bars—were constructed and tested to failure under quasi-static reversed cyclic lateral loading. The key studied parameters were: (1) use of bidiagonal web reinforcement; (2) use of bidiagonal sliding reinforcement; and (3) web reinforcement configuration (horizontal and/or vertical) and ratio. The reported test results clearly revealed that GFRP-reinforced concrete (RC) squat walls have a satisfactory strength and stable cyclic behavior as well as self-centering ability that assisted in avoiding sliding shear that occurred in the companion steel-reinforced wall following steel yielding. The results are promising regarding using GFRP-reinforced squat walls in areas prone to seismic risk where environmental conditions are adverse to steel reinforcement. Bidiagonal web reinforcement was shown to be more effective than conventional web reinforcement in controlling shear-cracks width. Using bidiagonal sliding reinforcement was demonstrated to be not necessary to prevent sliding shear. The horizontal web reinforcement ratio was found to have a significant effect in enhancing the ultimate strength and deformation capacity as long as the failure is dominant by diagonal tension. Existence of both horizontal and vertical web reinforcement was shown to be essential for cracks recovery. Assessment of the ultimate strengths using the available FRP-reinforced elements code and guidelines (CSA S806-12 and ACI 440.1R-15) was conducted and some recommendations were proposed to attain a reasonable estimation of ultimate strengths. Given their importance in estimating the walls’ later displacement, the effective flexural and shear stiffness of the investigated walls were evaluated. It was found that the cracked shear stiffness could be estimated based on the truss model; while the flexural stiffness can be estimated based on the available expressions in FRP-reinforced elements codes and guidelines. Based on a regression analysis, a simple model that directly correlates the flexural and shear stiffness degradation of the test walls to their top lateral drift was also proposed.
Résumé : La présente étude traite de la faisabilité de voiles courts en béton armé totalement renforcés avec des barres de polymères renforcés de fibres de verre (PRFV), obtenant une résistance et un déplacement latéral raisonnable par rapport aux exigences spécifiées dans divers codes. Neuf voiles à grande échelle ont été construits: un renforcé avec des barres d'acier (comme spécimen de référence) et huit renforcés totalement avec des barres de PRFV. Les voiles ont été testés jusqu’à la rupture sous une charge quasi-statique latérale cyclique inversée. Les voiles ont une hauteur de 2000 mm, une largeur de 1500 mm (élancement 2000 mm/1500 mm = 1,33) et une épaisseur de 200 mm. Les paramètres testés sont : 1) armature bi-diagonale dans l’âme; 2) armature bi-diagonale dans l’encastrement du mur à la fondation (zone de glissement); 3) configuration d’armature verticale et horizontale réparties dans l’âme et taux d’armature. Les résultats des essais ont clairement montré que les voiles courts en béton armé de PRFV ont une résistance satisfaisante et un comportement cyclique stable ainsi qu'une capacité d'auto-centrage qui ont aidé à éviter la rupture par glissement à l’encastrement (sliding shear). Ce mode de rupture (sliding shear) s’est produit pour le voile de référence armé d’acier après la plastification de l’armature. Les résultats sont prometteurs concernant l'utilisation de voiles en béton armé de PRFV dans les régions sismiques dans lesquelles les conditions environnementales sont défavorables à l’armature d’acier (corrosion). L’armature bi-diagonale en PRFV dans l’âme s’est avérée plus efficace pour le contrôle des largeurs de fissures de cisaillement comparativement à l’armature répartie dans l’âme. L'utilisation d'un renforcement de cisaillement bi-diagonal a été démontrée comme n'étant pas nécessaire dans les voiles courts en béton armé de PRFV pour prévenir la rupture par glissement à l’encastrement (shear sliding). Par ailleurs, les résultats d’essais ont montré que le taux d’armature horizontale répartie dans l’âme a un effet significatif sur l’augmentation de la résistance et la capacité en déformation des voiles dont la rupture par effort tranchant se fait par des fissures diagonales (tension failure). L'existence d’armature verticale et horizontale répartie dans l’âme du voile en béton armé de PRFV s'est révélée essentielle pour l’ouverture et la fermeture des fissures au cours des chargements cycliques. Les normes calcul CSA S806-12 et ACI 440.1R-15 ont été utilisées pour évaluer la résistance au cisaillement des voiles courts en béton armé de PRFV. Certaines recommandations ont été proposées pour obtenir une estimation raisonnable des forces ultimes. Compte tenu de leur importance dans l'estimation du déplacement latérale des voiles, la rigidité effective en flexion et en cisaillement des voiles étudiés a été évaluée. On a constaté que la raideur de cisaillement du béton fissuré pourrait être estimée en utilisant le modèle de treillis. La rigidité à la flexion peut être, quant à elle, estimée en fonction des expressions disponibles dans les normes et les guides de conception de membrures en béton armé avec des barres en PRFV. Sur la base d'une analyse de régression, un modèle simple qui corrèle directement la dégradation de la rigidité en flexion et en cisaillement des voiles courts en béton armé de PRFV testés avec le déplacement latérale dans la partie supérieure des voiles a également été proposé.

In this research, two new mechanical indentation frameworks were established where the two different indenters (cylindrical and ring-shaped flat-ended indenters) were integrated with ultrasound for assessing functional properties of articular cartilage during loading/unloading. The aim of establishing these framewoks was to address some of the limitations to the conventional indentation techniques. Two new parameters within these frameworks were developed and their capacity to distinguish between normal and different types of cartilage degeneration models during deformation/recovery, was investigated. The ring-shaped flat-ended indenter, integrated with an ultrasound transducer, was shown to be capable of distinguishing normal from artificially degraded bovine osteochondral samples.

In heavily settled areas, deformations induced by the tunnel excavation may cause serious damage to nearby structures. In this study it is aimed to model ground deformations induced by main tunnels and connection tunnels excavations as well as groundwater drainage. Therefore, it is necessary to study effective means of controlling tunnel induced deformations. The main parameters affecting the failure and deformation state of the soil around a circular underground opening are the physical characteristics of the soil, the diameter of the opening, and the support pressure. During the construction stage of Necatibey Station of KizilayÇ
ayyolu metro line (Ankara, Turkey), challenging ground conditions involving highly heterogeneous and locally water saturated foundation soils have been encountered. Possibility of damage at the surface and/or on the underground structures can be estimated using finite difference method (FDM) of analysis. In this study, two geophysical methods namely Electrical Resistivity Imaging (ERI) and Ground Penetrating Radar (GPR) were utilized to distinguish soil types at the study area. By correlating these geophysical survey results with the boring v logs, 3-Dimensional soil profile was revealed at the study area to build up a basis for numerical models. 3-Dimensional (3D) FDM analyses were conducted to assess tunneling induced deformations, along with movements around shallow soft ground main tunnels and connection tunnels. During sequential excavations, temporary and permanent shotcrete lining was also simulated. The soil behavior is assumed to be governed by an elastic-perfectly plastic constitutive relation based on the Mohr&ndash
Coulomb criterion. The computed deformations around these openings have been compared with the in-situ measurements. The results of the study revealed that the 3-D elasto-plastic analyses yield comparably good correlation with the in-situ measurements. Also, in this study, the effects of main tunnels excavations on each other and the effects of connection tunnels excavations on main tunnels were identified in terms of ground deformations. In order to simulate induced surface settlement due to groundwater withdrawal at the site 3-D fully coupled (fluidmechanical) numerical models were run using different time durations. The model studies revealed that deformations monitored at the ground surface are directly related with the tunnel construction practice. Pumping groundwater has very little or no effect on the measured deformations.

Ventilation imaging using 4D-CT is a convenient and cost effective functional imaging methodology which might be of value in radiotherapy treatment planning to spare functional lung volumes. To calculate ventilation imaging from 4D-CT we must use deformable image registration (DIR). This study validates the DIR methods and investigates the dependence of calculated ventilation on DIR methods and ventilation algorithms. The first hypothesis is if ventilation algorithms are robust then they will be insensitive to the precise DIR used provided the DIR is accurate. The second hypothesis is that the change in Houndsfield Unit (HU) method is less dependent on the DIR used and depends more on the CT image quality due to the inherent noise of HUs in normal CT imaging. DIR of the normal end expiration and inspiration phases of the 4D-CT images was used to correlate the voxels between the two respiratory phases. All DIR algorithms were validated using a 4D pixel-based and point-validated breathing thorax model, consisting of a 4D-CT image data set along with associated landmarks. Three different DIR algorithms, Optical Flow (OF), Diffeomorphic Demons (DD) and Diffeomorphic Morphons (DM), were retrospectively applied to the same group of 10 esophagus and 10 lung cancer cases all of which had associated 4D-CT image sets that encompassed the entire lung volume. Three different ventilation calculation algorithms were compared (Jacobian, ΔV, and HU) using the Dice similarity coefficient comparison. In the validation of the DIR algorithms, the average target registration errors with one standard deviation for the DIR algorithms were 1.6 ± 0.7 mm, maximum 3.1 mm for OF, 1.3 ± 0.6 mm, maximum 3.3 mm for DM, 1.3 ± 0.6 mm, maximum 2.8 mm for DD, indicating registration errors were within 2 voxels. Dependence of ventilation images on the DIR was greater for the ΔV and the Jacobian methods than for the HU method. The Dice similarity coefficient for 20% of low ventilation volume for ΔV was 0.33 ± 0.03 between OF and DM, 0.44 ± 0.05 between OF and DD and 0.51 ± 0.04 between DM and DD. The similarity comparisons for Jacobian was 0.32 ± 0.03, 0.44 ± 0.05 and 0.51 ± 0.04 respectively, and for HU 0.53 ± 0.03, 0.56 ± 0.03 and 0.76 ± 0.04 respectively. Dependence of ventilation images on the ventilation method used showed good agreement between the ΔV and Jacobian methods but differences between these two and the HU method were significantly greater. Dice similarity coefficient for using OF as DIR was 0.86 ± 0.01 between ΔV and Jacobian, 0.28 ± 0.04 between ΔV and HU and 0.28 ± 0.04 between Jacobian and HU respectively. When using DM or DD as DIR, similar values were obtained when comparing the different ventilation calculation methods. The similarity values for 20% of the high ventilation volume were close to those found for the 20% low ventilation volume. Mean target registration error for all three DIR methods was within one voxel suggesting that the registration done by either of the methods is quite accurate. Ventilation calculation from 4D-CT demonstrates some degree of dependency on the DIR algorithm employed. Similarities between ΔV and Jacobian are higher than between ΔV and HU and Jacobian and HU. This shows that ΔV and Jacobian are very similar, but HU is a very different ventilation calculation method.

This project aims to enhance relationships that quantify earthquake induced damage in reinforced concrete (RC) structures, in terms of Engineering Demand Parameters (EDPs) and/or Damage Indices DIs. In the seismic vulnerability assessment process structures are classified onto Damage Scales (DS) based upon their expected performance. The damage level is quantified by Damage Indices (DIs) as a function of Engineering Demand Parameters (EDPs). This research aims to enhance the relationships that quantify damage in Reinforced Concrete (RC) structures in terms of empirically derived EDPs equations as a function of material properties, geometrical properties of sections and detailing aspects. Current relationships found in literature are generally defined at yield and ultimate damage states, or at the occurrence of a particular failure mechanism in terms of chord rotation. Assessment procedures have however evolved from these two limit states onto multiple state assessment. Relationships referring to intermediate states of damage are therefore proposed. EDP relationships are derived from datasets of low cycle fatigue tests on columns found in literature. The number of elements with design and detailing aspects referring to old design practices are limited. Recent earthquakes have shown that such structures are very vulnerable. Hence, an experimental campaign consisting in RC elements with varying detailing aspects, material properties and geometric properties, designed to old design codes was conducted to enhance the dataset, act as a benchmark, and to investigate failure mechanisms. Low cycle fatigue tests generally refer to monotonic or cyclic loading patterns without any direct reference to earthquake loading or response. A procedure describing the determination of the loading history based on earthquake demands is therefore considered. The experiments also indicate that the loading pattern is a function of chord rotation capacity. This effect is taken into account in the development of the EDP relationships. Multivariable stepwise regression was used for the development of the EDP relationships. The selection of the explanatory variables was based on significant parameters used in existing EDP relationships, parameters found in existing relationships describing particular failure modes, and dimensional analysis. A comprehensive model of chord rotation and stiffness are provided at yielding, maximum force, 10% maximum force reduction, 20% maximum force reduction and 50% maximum force reduction. Relationships that relate residual stiffness, chord rotation and energy dissipation are derived. The testing campaign on columns not only highlights the behaviour of reinforced concrete designed without seismic detailing, but adds to the database in literature. The beam-column connection tests indicate that the behaviour at the nodes affects the behaviour of RC structures, and stress the importance of their inclusion in further investigations. Finally, proposing a method to determine lowcycle fatigue loading regimes based on seismic response is an attempt to address an anomaly where tools that are used to quantify seismic damage are not linked in any way with earthquakes.

Thesis advisor: Seth C. Kruckenberg
The West Antarctic rift system is one of the most expansive regions of extended continental crust on Earth, but relatively little is known about the structure of the mantle lithosphere in this region. This research aims to examine a suite of ultramafic mantle xenoliths from several volcanic centers located throughout Marie Byrd Land, West Antarctica. Through the use of several complementary analytical methods, the deformational and compositional heterogeneity of the lithospheric mantle in this region is characterized. The Marie Byrd Land xenoliths have equilibration temperatures between 779 and 1198°C, which is a range that corresponds to extraction depths between 39 and 72 km. These samples preserve significant mineralogical and microstructural heterogeneities that document both lateral and vertical heterogeneities within the Marie Byrd Land mantle lithosphere. The modal mineralogy of spinel peridotites varies between 40 – 99% olivine, 0 – 42% diopside, 0 – 45% enstatite and 0 – 5% chromite. Minimum olivine grain sizes range from 60 to 110 µm and maximum olivine grain sizes range from 2.5 to 10.0 mm. The geometric mean grain size of olivine in these samples ranges from 100 µm to 2 mm and has an average of 694 µm. The geometric mean grain size of diopside ranges from 90 to 865 µm and has an average of 325 µm, whereas that of enstatite ranges from 120 µm to 1.2 mm and has an average of 625 µm. Comparatively, the pyroxenites contain 0 – 29% olivine, 29 – 95% diopside, 1 – 36% enstatite and 1 – 11% chromite. Deformation mechanism maps suggest that the olivine within the MBL peridotite xenoliths primarily accommodate strain through the operation of dislocation-accommodated grain-boundary sliding at strain rates between 10-19/s and 10-11/s. This is consistent with microstructural observations of the suite made using optical microscopy (e.g., deformation bands and subgrains in olivine; aligned grain boundaries between contrasting phases). Application of the olivine grain size piezometer indicates that the suite preserves differential stresses ranging from 0.5 MPa to 50 MPa, with mean differential stresses ranging from 4 to 30 MPa. Values of mean differential stress only vary slightly throughout the field area, but generally decrease in magnitude towards the east with maximum values migrating upwards in the lithospheric mantle along this transect. The samples from some volcanic centers are highly homogenous with respect to their microstructural characteristics (e.g., Mount Avers – Bird Bluff), whereas others display heterogeneities on the sub-five-kilometer-scale (e.g., Demas Bluff). Comparatively, mineralogical heterogeneities are more consistent throughout the sample suite with variations generally being observed between the sub-five-kilometer-scale and the sub-ten-kilometer-scale. Most samples within the MBL peridotite suite display axial-[010] or A-type olivine textures. Although less dominant, axial-[100], B-type and random olivine textures are also documented within the suite. Axial-[010] textures have J-indices and M-indices ranging from 1.7 – 4.1 and 0.08 – 0.21, respectively. The average value of the J-index for axial-[010] textures is 2.9, whereas the average M-index of these samples is equal to 0.15. Overall, A-type textures tend to be stronger with J- and M-indices ranging from 1.4 – 9.0 and 0.07 – 0.37, respectively. The olivine crystallographic textures of the MBL xenolith suite are heterogeneous on scales that are smaller than the highest resolution that is attainable using contemporary geophysical methods, which implies that patterns of mantle flow and deformation are far more complex than these studies suggest
Thesis (MS) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences

Left ventricular (LV) ejection fraction (EF) derived from two-dimensional echocardiography has been the cornerstone for LV function assessment for more than half a century. However, EF is only an indirect measure of cardiac output obtained from changes in LV volume, and does not necessarily reflect intrinsic myocardial contractile properties. Furthermore, LVEF measurement has a number of challenges that relate to image quality, LV geometry assumptions, and technical expertise, and has significant issues with intra-observer, inter-observer, and test-retest variability. A more contemporary marker of LV systolic function is speckle tracking echocardiography (STE)-based global longitudinal strain (GLS). Based on deformation of the cardiac muscle, GLS provides a more direct evaluation of myocardial contractile function. GLS is highly sensitive for the detection of overt LV dysfunction, as well as subclinical LV systolic impairment when LVEF is still considered normal. Furthermore, longitudinal strain has great utility in the evaluation of right ventricular (RV) function, as well as atrial function. Two-dimensional GLS, derived from semiautomatic software, has a high temporal and spatial resolution and consequently, improved inter- and intra-observer reproducibility, compared to LVEF. The overall aim of this thesis was to explore the role of STE-derived GLS in a variety of cardiovascular conditions. Firstly, the utility of GLS in patients with ventricular arrhythmias was assessed, including patients with and without structural heart disease. GLS in cardio-oncology, specifically left-sided breast cancer patients undergoing radiation therapy, was also evaluated. RV strain in patients with pulmonary embolism was studied in order to identify its role in the management of these patients. Finally, left atrial function, including left atrial strain, was addressed in a population of elite athletes with and without atrial fibrillation and compared to non-athletes.

Cardiovascular diseases are responsible for approximately a third of all death worldwide, with hypertension being a major risk factor for many of those. Hypertension can lead to left ventricle hypertrophy and diastolic and systolic dysfunction. Myocardial deformation parameters have been shown to have high sensitivity at the early stage of contractile dysfunction. They can be derived from myocardial tagging, considered to be the goldstandard method, or from routinely acquired cine images using feature tracking (FT) techniques. This work aimed to validate FT as a post processing technique. Three FT software packages were used to measure strain parameters in healthy subjects and hypertensive patients in order to assess agreement. Intra- and inter-observer reproducibility was also investigated. The CVI42 software was found to have the best reproducibility. Good agreement across the three software packages and both groups was also observed for circumferential strain calculated from mid-ventricle short axis and longitudinal strain parameters. CVI42 was also compared to the reference tagging analysis by applying both techniques to a healthy and hypertensive patient cohort. Although tagging could discriminate between the two populations (longitudinal strain), no statistically significant differences were found by CVI42. The final validation step was to generate simulation models mimicking simplified cardiac views to compare the experimental results against a true gold-standard for which strain values are known. Two commercial FT software packages were used to analyze the simulated cine images with increasing complexity levels. Both showed inaccurate tracking and high errors compared to analytical values. This indicated that more realistic and complex numerical models should be investigated. Although FT is a relatively new and promising technique, the results demonstrated that it still requires going through standardization to better understand inter-vendor variability.

Cardiac magnetic resonance (CMR) imaging is the gold standard imaging technique for assessment of ventricular dimensions and function. CMR also allows assessment of ventricular deformation but this requires additional imaging sequences and time consuming post processing which has limited its widespread use. A novel CMR analysis software package, ‘feature tracking’ (Tom Tec, Germany) can measure ventricular deformation directly from cine CMR images. This thesis seeks to further our understanding of the feasibility of feature tracking to assess myocardial deformation and volumetric measures. Chapter 3 validates normal ranges for deformation parameters and compares values against traditional tagging measures. The work identifies global circumferential strain measures as being the most reproducible. In chapters 4 and 5, feature tracking values for left and right ventricular strain are compared with echocardiography derived speckle tracking indices of deformation. For left ventricular (LV) parameters, circumferential and longitudinal strain are most consistent and for the right ventricular (RV) measures, assessment of free wall strain using feature tracking shows promise and with modifications in algorithms is likely to further improve in the future. Chapter 6 assesses the ability of feature tracking to measure diastolic function. The results show that radial diastolic velocities and longitudinal diastolic strain rates can predict diastolic dysfunction (as diagnosed by echocardiography) with acceptable levels of sensitivity and specificity, particularly when used in combination. 11 The use of feature tracking to provide automated measures of ventricular volumes, mass and ejection fraction is assessed in chapter 7. Feature tracking in this context shows acceptable correlation but poor absolute agreement with manual contouring and further adjustments to algorithms is necessary to improve its accuracy. This work offers insights into the use of feature tracking for the assessment of ventricular deformation parameters. It is a technique with advantages over CMR tagging methods and given the speed of post processing has the potential to become the CMR preferred assessment for strain quantification in the future.

A basic requirement for safe geological storage of CO2 is the ability and integrity of the storage complex to contain the CO2. However, the storage formation and the caprock may contain fractures and/or faults that could provide a permeable conduit for CO2 migration out of the prime storage formation. Furthermore, CO2 injection may induce or reactivate fracture networks and faults providing a pathway for CO2 leakage. Recent experience from large scale industrial CO2 storage projects have shown that the geomechanical response of structural features to CO2 injection is a critical parameter controlling the injection performance. The monitoring of the geomechanical response using InSAR surface deformation, injection pressure data and seismic data have provided valuable insight into CO2 injection and storage performance. There is, however, a need for greater integration between monitored data and numerical modelling techniques used to assess performance in order to establish the conformity of the actual behaviour of the injected CO2 with the modelled behaviour. Research presented in this thesis developed an integrated performance assessment methodology for CO2 storage sites, which incorporates satellite (InSAR) monitoring data, time-lapse seismic monitoring data, bottom hole pressure (BHP) data, inverse modelling, and coupled flow-geomechanical simulations using the ensemble Kalman filter (EnKF). The developed methodology has been applied to the In Salah CO2 storage field dataset in order to demonstrate its application and usefulness for the performance assessment of CO2 storage sites. First, an inversion scheme using Weiner filters based on a numerical geomechanical model was developed and used to invert InSAR surface deformation for reservoir pressure change. A forward coupled flow-geomechanical modelling study in conjunction with an InSAR and time-lapse seismic analysis was then performed. This lead to an improved understanding of the flow and pressure behaviour at one of the injection wells. Finally, an integrated approach combining inverse and forward modelling using the EnKF was developed and applied. The EnKF tool developed provides a framework for the updating of flow and geomechanical model parameters through the joint assimilation of bottom hole pressure and InSAR data.

Magíster en Minería. Ingeniero Civil de Minas
La geomecánica y planificación minera son áreas de la minería a cielo abierto íntimamente relacionadas, ya que las restricciones geomecánicas limitan al diseño minero y, así, los planes mineros factibles. El diseño y los planes mineros han de empujar los límites de lo que la geomecánica permite, para asegurar operaciones mineras competitivas y mantener un nivel de riesgo al personal y operaciones aceptable. Luego, se requiere del monitoreo geotécnico para adquirir datos de calidad que permitan un diseño minero de alto nivel. Sin embargo, la relación entre geomecánica y planificación minera no se extiende al diseño e implementación de programas de monitoreo. En general, los programas de monitoreo de deformaciones superficiales son diseñados con posterioridad al inicio de la operación del rajo y cuando se han identificado signos de inestabilidad en la superficie de los taludes. El monitoreo de deformaciones del subsuelo permite alertar sobre fallas en desarrollo semanas antes de que estas se hagan notar en superficie. Luego, se debería diseñar campañas de monitoreo de deformaciones del subsuelo durante el proceso de planificación minera, considerando el diseño minero en la instalación de instrumentos geotécnicos previo a la construcción de la mina. Lo que permitiría registrar el proceso de relajación del macizo a medida que la construcción progresa y adquirir datos más exhaustivos del comportamiento del macizo rocoso (antes que con monitoreo superficial), con el fin de optimizar el diseño de taludes futuros y adoptar medidas correctivas para evitar fallas. En esta tesis, fueron diseñadas una serie de campañas de monitoreo de deformaciones del subsuelo usando In-Place Inclinometers, ShapeAccelArrays y Networked Smart Markers (NSMs) como equipos de monitoreo. Las opciones fueron aplicadas a una mina teórica desarrollada como parte de la tesis y comparadas en términos de costos, cantidad y calidad de los datos recopilados. Los resultados indican a la opción de NSMs cada 2[m] como la más eficiente en cuanto a costos ya que: (1) presenta el menor costo por unidad de datos adquiridos (US$57.21) y (2) 5 veces mayor vida útil, lo que permitiría obtener el doble de datos que la siguiente mejor opción, (3) se financia con un aumento de 2° en el ángulo de talud y (4) aumenta el VAN del proyecto en 3.2%.
Open pit geomechanics and mine planning are two closely related areas in the development of an open pit mine since geotechnical constrains limit the possible mine designs and, thus, the feasible mine plans. Mine designs and plans have to push the limits of what rock mass geomechanics allow to assure competitive mine operations, while maintaining acceptable levels of risk to operations and personnel. Therefore, geotechnical monitoring programs are required to acquire good quality data to be used as input for mine design. However, the relation between geomechanics and mine planning does not extend to monitoring programs design and implementation. Generally, surface deformation monitoring programs are designed after the project is in operation and signs of slope instability have been identified on the surface. Subsurface deformation monitoring can alert about developing failures weeks before any sign of instability is noted on the surface. Therefore, subsurface deformation monitoring campaigns should be designed along the mine planning process and considering the mine s design to install geotechnical instrumentation prior to the construction of the slopes. This methodology would allow to register the rock mass relaxation process as construction progresses and to acquire more comprehensive data about rock mass behaviour, in advanced of surface monitoring, towards future slope design optimization and adoption of remedial measurements to avoid failure. In this thesis, a series of subsurface deformation monitoring campaign were designed using In-Place Inclinometers, ShapeAccelArrays and Networked Smart Markers as monitoring devices. All options were applied to a theoretical open pit developed as part of this work. The campaigns were compared in terms of cost, quantity and quality of gathered data. The results showed that the campaign using NSMs installed every 2 meters was the most cost-efficient option as it represented: (1) the lowest cost per unit of gathered data (US$57.21), (2) five times longer lifespan, which allowed to gather twofold the amount of data compared with the next best option, (3) be financing of the campaign through steepening of the slopes by 2° and (4) increase in project s original NPV by 3.2%.

Information about deformation in an area has become vital not only for safety assessment but also for maintenance of geodetic infrastructures. The latter is necessary to support accurate surveying and mapping applications. This research exploits the complementary features of Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) techniques to assess the long-term deformation in Johor, Malaysia, which can be induced by natural and/or anthropogenic activities. Furthermore, modelling and mitigation of tropospheric effects in GPS and InSAR are addressed to achieve the best possible precision from the two techniques. Indeed, their modelling and mitigation improve the quality of the estimation as well as provide valuable resources for atmospheric studies. The assessment of long-term deformation in Johor is firstly made by analysing the five years (2007 - 2011) point-specific profile at eight Malaysia Real-Time Kinematic GNSS Network (MyRTKnet) stations. Two processing strategies, namely Precise Point Positioning (PPP) and Double-Difference (DD), are employed to assess their capability for deformation monitoring. The latter also make used of the GPS data from 27 IGb08 stations and 7 International GNSS Service (IGS) stations. Analysis of the results revealed deformation that can be explained by plate tectonic movement and earthquakes in the surrounding region. While results from the PPP processing showed a higher correlation with the recorded earthquakes, the results from DD have improved correlation coefficients at about 4% in the East-West and 5% in the Up-Down components. These improvements are valuable when the rate of deformation is the primary interest. In addition to the point-specific profile, the surrounding deformation of Johor has been assessed with the line-of-sight (LOS) velocity maps from the InSAR time-series. Two sets of ERS-1/2 data, consisting a total of 67 images acquired at two descending tracks (i.e. track 75 and 347), are utilised for the generation of the maps. Moreover, the feasibility of Sentinel-1 satellites is also tested, which revealed improved coherence owing to their short revisit cycle. Some part of Johor showed subsidence and uplift trends, which also agreed with the literature. This information cannot be perceived by the GPS alone due to its limited coverage; hence, further attests to the benefit of their joint analysis. Numerous developments have been implemented in the in-house software (i.e. Punnet) such as the implementation of tropospheric correction, outlier’s rejection scheme, statistical analysis to identify the control point for phase unwrapping, and a new method to retrieve temporal evolution of deformation for a rapidly deforming area.

There is an impetus in the UK to move away from empirical pavement foundation design and the current method specification, towards an analytical design approach. For an analytical design approach to be adopted, the required performance properties of stiffness and resistance to permanent deformation of the foundation materials (sub grade and capping) need to be measured, both in the laboratory for design and in the field in order to ensure compliance. This thesis studies the influence of the sub grade on the constructability and performance of a series of full-scale pavement foundations. This has been achieved by measuring the performance parameters of several sub grade materials in the laboratory, using repeated load triaxial testing. These data have been compared to comparable data collected in situ using dynamic stiffness measuring devices during the construction of trial pavement foundations. The performance of the trial foundations has been measured during the placement and compaction of the different foundation materials, and again after their subsequent trafficking. The testing demonstrates the stress dependency of the foundation materials. The laboratory testing shows that the sub grade permanent deformation under cyclic loading (used to simulate construction operations) becomes unstable at a deviator stress of half the deviator stress at failure (0.5qmax)· The stiffness at this applied stress and above is shown to be approaching a consistent value. This indicates that large changes in the stiffness of inversely stress dependent fine grained soils occur below the deviator stress at which the permanent deformation becomes unstable. Significant variability of data has been found in the performance parameters measured (both in the laboratory and in the field) for samples of subgrade collected from small areas of the same site. However comparable patterns of stress dependency have been observed between measured laboratory and field performance using the different apparatus. The resistance to permanent deformation is shown to be a more critical design load case for construction than the need for adequate stiffness of support required to compact the foundation layers. The performance of a composite road foundation is shown to be material and site specific, and this will have important implications for design and site compliance testing.

Grade 91 steel has been extensively used for high temperature since it was introduced in the 1980s. However, as the 9%Cr material is relatively new, there is limited experimental data and understanding with respect to quantifying the effect of variables, for example service exposure, on life prediction and long-term behaviour, in particularly weldment. Many incidents reported about premature weld failures of Grade 91 steel suggest that the design standards and guidelines may be non-conservative for the pressure vessels and piping made of Grade 91 steel. Furthermore, Grade 91 welds are also known to be prone to Type IV cracking, leading to premature failure controlled by creep crack growth (CCG). A comprehensive literature review was carried out and extensive data is collected. This includes data for a different range of steel materials at different creep temperatures and test stress which in turn provided a range of test durations from a few hundred hours to several thousand hours (ie > 60,000 hours) but with the main focus of the analyses remaining on Grade 91. The NSW based creep crack growth model is found to be capable of predicting upper/lower bounds of creep crack growth well for Grade 91 when data is obtained from relatively short to medium-term laboratory experiments (< 10,000 hours). It is also found that the extrapolation of the model fails to predict the long-term creep crack propagation rates unless the actual long-term uniaxial creep data is available. Two types of creep testing are performed in this study to investigate the creep behaviour of Grade 91 steel over a range of stresses on the basis of continuum damage mechanics and fracture mechanics: Uniaxial creep and CCG. For each type of testing, creep deformation behaviour and CCG characteristics in different microstructures (parent metal, weld metal and HAZ) are investigated. The same tests are performed on as-received and service exposed Grade 91 steel to provide the relevant data to be used for the NSW prediction model. In both uniaxial and CCG experiments, the weldment (ie weld metal and HAZ) exhibits a lower creep resistance compared to the parent material. In the CCG experiments, the ex-service material exhibits a faster growth rate compared to the as-received material in the similar range of C*. Based on the test results, the relevant parameters to describe creep strength and CCG are established. The results of the analyses of short-term and long-term creep data from the literature indicate a change in the creep exponent and failure strain at longer creep lives. The creep failure strain also tends to diminish with a decrease in the applied stress. To investigate the microstructure of the steel before and after the creep test and to also understand the failure mode and the location in the uniaxial and CCG tests, metallography was carried out. One sample from both service exposed and as-received steel before any creep test as well as one uniaxial and one CCG specimen from each material (four in total) after creep tests were selected for examination. Both service exposed and as-received steels showed tempered martensite microstructure with cavities observed in the service exposed material before the test. The analyses of creep uniaxial samples after the test exhibit Type IV failure tendency in the as-received material compared to the service exposed steel where failure occurred mainly at or adjacent to the weld. With regards to the CT specimen, in a similar way the crack path in the as-received HAZ sample followed outer region of HAZ (ie. Type IV) whereas the crack path in the service exposed sample showed tendency to grow along the fusion line. This may be due to faster ageing process of the weld metal compared with HAZ and parent material when exposed to high temperature. The experimental results obtained above together with the database compiled from the literature survey are then used, in conjunction with the NSW model, to predict the CCG of Grade 91 steel. It is found that the appropriate failure strain under multi-axial stress state can be estimated by extrapolating the secondary strain to the failure time rather than the final failure strain. Using the extrapolated uniaxial failure strain data at the lower shelf (low stress) region and a reduced creep index at long terms, conservative CCG predictions have been made by the NSW model. For C* values of 10-5MJ/m2h and less, cracking is predicted to be relatively faster compared to the extrapolated short-term CCG data trend. It is found that the assumption of lower failure strains and reduced creep indices effectively produce a safe prediction for CCG using the NSW model for long-term behaviour. However, the level of conservatism increases depending on the use of uniaxial failure strains or the Monkman-Grant (MMG) failure strain or in the extreme 0.2% failure strain as the lower shelf data. The correct level of conservatism can only be determined once actual long-term CCG data are available. Following the analysis, a prototype model was developed based on risk-based life assessment (RBLA) integrity management concept using data presented in this thesis for Grade 91 piping material. Estimating remaining life based on the material limit state equation, assessing the risk associated with creep damage and making recommendations on the most effective mitigation plan were the main area of assessment treated in the RBLA model. In this study, four reported Grade 91 weld failure investigations have been compared to the assessment result from RBLA. The result was found to be similar to what the failure investigation reported, however it should be noted that when applying the risk concept, the target risk (or target probability) plays a crucial role compared to a deterministic analysis. The work done on failure cases and the comparison with models developed in this thesis demonstrated that to achieve a reliable conservative result for longer-term CCG assessment, the effect of lower creep ductility due to long-term exposure together with MMG approach to determine a lower band failure strain should be taken into consideration. Where crack growth data was available from the failure investigation report, a comparison with the finding from the investigation was made with the long-term NSW model which was developed in this work. The result indicated a good agreement with finding from the failure investigation report and falls in the scatter band predicted from the model. It could be concluded that the optimum approach to predict the short-term and especially long-term creep and CCG behaviour of Grade 91 weldment is a probabilistic method as the level of uncertainty is relatively high in material properties those contributing to failure.

Simulations are powerful and important tools for gaining insight into powder processes. Ultimately, simulations have the potential to replace experiments. Thus, accurate models and insight into the essential factors for descriptions of powder behaviour are required. In this thesis, discrete element method (DEM) simulations of granule flow and compression were evaluated to deduce parameters and potential models essential for the experimental and numerical correspondence. In addition, the evolution in tablet microstructure during compression was studied using mercury porosimetry. Granule flow was measured using angle of repose, discharge rate, and shear. The granular flow depended primarily on particle shape and surface texture due to the mutual influence of these two parameters on the inter-particle forces. Rolling friction stabilised both the heap formation and promoted shear in the elastic quasi-static flow regime. Thus, rolling friction was established to be an essential simulation parameter for the correspondence to experiments. Current compression models often neglect the elastic compact deformation during particle loading. In this thesis, two fundamentally different models were evaluated with focus of including the elastic deformation. The first model comprised a maximal particle overlap, where elastic deformation commences. The second model accounted for the contact dependence and impingement at high relative densities. This model was based on a truncated-sphere followed by a Voronoi extension. The validity of the models was demonstrated by the elastic qualitative correspondence to experimental compressions for ductile materials. In tablets, the void (inter-granular pore) diameter was dependent on the degree of compression. Thus, the degree of compression provides an indication of the tablet microstructure. The microstructure was subsequently observed to be related to the tablet tensile strength as inferred from a percolation threshold required for formation of coherent tablets. In summary, this thesis has shed light onto the potential of simulating flow and compression of granulated pharmaceutical powders using DEM. Continuous work in the area are required to further improve the models to increase the experimental and numerical correspondence.

A new reliability-based probabilistic model is developed for the estimation of liquefaction-induced lateral ground spreading, taking into consideration the uncertainties within the model functional form and the descriptive variables as well. The new model is also introduced as performance-based probabilistic engineering tool.

Image Correlation techniques are increasing in popularity and are now suitable to investigate complex structural and fluid-dynamics of cardiovascular systems. These approaches operate through a digital correlation of a pair of images to determine physical quantities of complex systems. In this thesis, their application to the mechanical characterisation of complex biomaterials (Nitinol and soft materials), and the characterisation of complex biofluid-dynamics was investigated, with the aim to analyse their reliability and enhance their accuracy and field of application. Digital Image Correlation, supported by Infrared Thermography, was used to achieve a more in depth understanding of the mechanical behaviour of Nitinol shape memory alloys. The analysis led to the design of a new approach that minimise the error of standard characterisation methods. Application of DIC to soft materials focused on biaxial test protocols commonly adopted in their characterisation. These were investigated, identifying major drawbacks that reduce the accuracy of the results. A new setup arrangement of easy implementation was developed to reduce the source of errors from above 50% to below 20%. For the characterisation of complex biofluid-dynamics, a new Particle Image Velocimetry (PIV) approach was attempted to improve the current estimation of the Effective Orifice Area (the leading parameter in heart valves characterisation) by allowing its direct measurement. Previously unreported limitations in the application of PIV to the analysis of the fluid-dynamics in complex cardiovascular cases were identified and investigated by implementing a new approach based on the use of SPH (Smoothed-particle hydrodynamics) Synthetic Images. Image correlation techniques were also used to address another experimental issue typical of PIV applications in cardiovascular engineering, the refractive index mismatch between blood equivalent test fluid and the anatomical phantoms. In particular, a new blood equivalent was developed, with similar density and viscosity as human blood at body temperature. This has same refractive index as a new optically transparent silicone (FER-7061), for which a prototyping protocol was implemented. In summary, this thesis presents a range of studies focused on applications of digital image correlation to cardiovascular engineering, making a distinct contribution to the state of knowledge in the area by identifying main limitations of the different methods and proposing new original approaches that allow to minimise them, to better support the development and assessment of safer and more effective cardiovascular solutions.

The aim of the master’s thesis was t odevelop alternative solutions supporting steel structure of the railway bridge on the undermined area. The range of single fields were chosen based on the location of existing substructures. Reducing the width of bridge openings were not allowed. Based on the geodetic survey plans were drawn up clear of the current state. On the basis of specifications for developing a detailed process was chosen variant Gerber’s beam reinforced with an arch in mean field. For this variant was performed structural analysis of the main parts of the main structure of the bridge, which was calculated with the effects of undermining. For variant Gerber’s beam were made clear drawings and drawing details of the selected steel bridge construction (new state). Further, detailed analysis of selected structural detail was made. Specifically, connecting rod to the main beam, which was designed optimal shape and thickness of the joints plate with a suitable radius of the firing to avoid plastification of the material in this area. Variant of the continuous beam without joints was prepared to. It has been observed, what is the effect of undermining on the stress in the construction of the bridge - was confronted with the effects on Gerber’s beam. To reduce stress in the construction of the bridge and compliance of ultimate state of applicability of the main beam has been designed bearing adjustment and after considering several options its implementation too. The economic comparison between the two variants was conducted. The assembling procedure was designed for both types of bridge structures. In the technical report we can read about due to the intention of building a new bridge and further we can find there other important technical information. In conclusion of the master’s thesis there has been recommended for the construction specific variant – from the perspective of an investor, and from the static aspect-view of the designer.

Der untertägige Abbau von Steinkohle führt zu Bewegungen des überlagernden Gebirges und der Tagesoberfläche. Eine Bewegungsprognose ist im Hinblick auf entstehende Bergschäden weltweit von großer Bedeutung. In dieser Arbeit wird untersucht, ob eine Prognose von Bodenbewegungen im amerikanischen Steinkohlenbergbau mit einem in Europa bewährten Verfahren, einem dynamischen stochastischen Senkungsmodell, möglich ist. Dazu wurde eine Literaturstudie über den bisherigen Kenntnisstand in den USA durchgeführt, abbaubegleitende Bodenbewegungsmessungen aus dem Steinkohlengebiet der Appalachen ausgewertet und durch Modellrechnungen nachgebildet. Es wurde darüber hinaus untersucht, welchen Einfluss die spezifischen Abbaubedingungen und die räumliche und zeitliche Abbauführung auf die Größe und Dynamik von Bodenbewegungen haben. Die theoretischen und praktischen Untersuchungen zeigen einen deutlichen Know-how Vorsprung des europäischen Bergbaus in den Bereichen der Senkungsmodellierung und Bewertung abbauinduzierter Bodenbewegungen und belegen die Anwendbarkeit des Senkungsmodells. Es wurden wichtige Erkenntnisse gewonnen, die Möglichkeiten und Grenzen einer Optimierung des Abbauzuschnitts und der zeitlichen Abbauführung im Sinne einer bergschadensmindernden Abbauplanung aufzeigen. Die Arbeit trägt zur Verbesserung der bergmännischen und markscheiderischen Abbauplanung im Steinkohlenbergbau bei.

This thesis focuses on the development of a new method for the continuous

monitoring of civil engineering structures in order to locate small damages automatically. A

review of the very wide literature on Structural Health Monitoring (SHM) points first out that

the methods can be grouped in four categories based on their need or not of a numerical model,

as well as their need or not of information of the damaged structure to be applied. This state

of the art of the SHM methods highlights the requirement to reach each levels of SHM, which

is in particular for the localization of small damages in civil engineering structures the needs

for a non-model based output-only damage sensitive feature extraction technique. The origin of

the local sensitivity of strains to damages is also analyzed, which justifies their use for damage

localization.

A new method based on the modal filtering technique which consists in combining linearly

the sensor responses in a specific way to mimic a single degree of freedom system and which

was previously developed for damage detection is proposed. A very large network of dynamic

strain sensors is deployed on the structure and split into several independent local sensor networks.

Low computational cost and fast signal processing techniques are coupled to statistical

control charts for robust and fully automated damage localization.

The efficiency of the method is demonstrated using time-domain simulated data on a simply

supported beam and a three-dimensional bridge structure. The method is able to detect and

locate very small damages even in the presence of noise on the measurements and variability

of the baseline structure if strain sensors are used. The difficulty to locate damages from acceleration

sensors is also clearly illustrated. The most common classical methods for damage

localization are applied on the simply supported beam and the results show that the modal filtering

technique presents much better performances for an accurate localization of small damages

and is easier to automate.

An improvement of the modal filters method referred to as adaptive modal filters is next

proposed in order to enhance the ability to localize small damages, as well as to follow their

evolution through modal filters updating. Based on this study, a new damage sensitive feature

is proposed and is compared with other damage sensitive features to detect the damages with

modal filters to demonstrate its interest. These expectations are verified numerically with the

three-dimensional bridge structure, and the results show that the adaptation of the modal filters

increases the sensitivity of local filters to damages.

Experimental tests have been led first to check the feasibility of modal filters to detect damages

when they are used with accelerometers. Two case studies are considered. The first work

investigates the experimental damage detection of a small aircraft wing equipped with a network

of 15 accelerometers, one force transducer and excited with an electro-dynamic shaker. A

damage is introduced by replacing inspection panels with damaged panels. A modified version

of the modal filtering technique is applied and compared with the damage detection based principal

component analysis of FRFs as well as of transmissibilities. The three approaches succeed

in the damage detection but we illustrate the advantage of using the modal filtering algorithm as

well as of the new damage sensitive feature. The second experimental application aims at detecting

both linear and nonlinear damage scenarios using the responses of four accelerometers

installed on the three-storey frame structure previously developed and studied at Los Alamos

National Labs. In particular, modal filters are shown to be sensitive to both types of damages,

but cannot make the distinction between linear and nonlinear damages.

Finally, the new method is tested experimentally to locate damages by considering cheap

piezoelectric patches (PVDF) for dynamic strain measurements. Again, two case studies are investigated.

The first work investigates a small clamped-free steel plate equipped with 8 PVDFs sensors, and excited with a PZT patch. A small damage is introduced at different locations by

fixing a stiffener. The modal filters are applied on three local filters in order to locate damage.

Univariate control charts allow to locate automatically all the damage positions correctly.

The last experimental investigation is devoted to a 3.78m long I-steel beam equipped with 20

PVDFs sensors and excited with an electro-dynamic shaker. Again, a small stiffener is added to

mimic the effect of a small damage and five local filters are defined to locate the damage. The

damage is correctly located for several positions, and the interest of including measurements

under different environmental conditions for the baseline as well as overlapping the local filters

is illustrated.

The very nice results obtained with these first experimental applications of modal filters

based on strains show the real interest of this very low computational cost method for outputonly

non-model based automated damage localization of real structures.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

碩士
國立中興大學
土木工程學系所
105
There are so many hills and rivers in Taiwan that it is blessed with abundant ecological resources. For better environmental protection, many main road predominantly constructed on viaduct. Viaducts are usually prestressed concrete bridge and built by cantilever method. In this thesis, the study target was a curved viaduct, which assorted well with locally snaking terrain. Midas Civil, a software for structural analysis, was used to simulate its mechanical behavior due to self-weight and prestress. Firstly, Midas Civil was used to build models for the study bridge, then the model was used to analyze the mechanical behavior due to self-weight and prestress. Next, CSIBridge and Midas were used to verify the authenticity of the simulation result from Midas Civil. By comparing the deformation diagrams and stress diagrams from both models, it showed that the result was somewhat consistent. Finally, by comparing the self-weight deformation diagrams for the straight bridge and the curved one, the way was studies how curvature affected the mechanical behavior of bridge. The result showed that the mechanical behavior of curved bridge could not be predicted precisely by means of straight bridge, in case where the difference between both deformations was too large.

碩士
國立臺灣科技大學
營建工程系
87
The safety assessment of tunneling can be evaluated either from stresses or from deformation. Most safety management criterion of tunnel in Taiwan are related to deformation due that deformation is easier to monitor than stress. The behavior of deformation and stresses nearby excavation face should be three-dimensional, but at present lots of engineers still use two-dimensional numerical simulation and their experience to set that criterion due to the lack of software or the limitation of computable time. One better way to fully understand tunneling behavior is to use three-dimensional numerical simulation and back-analysis from monitoring. However, researches regarding three-dimensional numerical simulation are still lacking。 This research used three-dimensional numerical analysis software FLAC3D to analyze tunneling. The tunnel shape is Triple-circular-arcs that often seen in freeway. The roof settlement and internal deformation convergence are conferred under various rock mass、compressive strengthσc、 and bench cut length in the study. Finally, some conclusion related prior deformation before monitoring、 monitoring delay influence、and the safety assessment consideration are proposed.

Echocardiography has become a very important diagnostic exam in veterinary cardiology, being consider as the exam of choice in many of the small animals cardiopathies. Recently, new echocardiographic techniques have been studied with the intent of improving diagnostic accuracy, introducing new parameters on the routine echocardiographic exam. These techniques, namely Tissue Doppler imaging and Specke Tracking, are already well established in human medicine cardiology and many studies have proven their value and effectiveness. During the last decade, these techniques have also been studied in veterinary medicine. Tissue Doppler imaging and Bi-dimensional Speckle Tracking deliver new parameters in evaluating the myocardium performance, as the evaluation of the deformation indices (Strain and Strain Rate), ventricular torsion and synchrony. In this review, relevance will be given to these parameters and how they affect changes on the left ventricle. This will be achieved by gathering studies recently made in various cardiopathies, as well as the normal values for myocardial deformation in healthy animals. This review will also focus on these techniques’ ability to detect early changes, allowing the clinicians to use proper and timely therapeutic decisions. This is a very important factor, since it could have impact on definitive diagnosis and future prognosis of several diseases.
Em Medicina Veterinária, a ecocardiografia tornou-se um exame complementar de extrema importância no diagnóstico definitivo de várias cardiopatias, sendo considerada como o método diagnóstico de eleição. Recentemente, novas modalidades ecocardiográficas têm sido estudadas com o intuito de melhorar a capacidade de diagnóstico e introduzir novos parâmetros no exame ecocardiográfico de rotina. Em Medicina Humana, as referidas ténicas de ecocardiografia mais avançadas, como o Doppler tecidular e o Speckle Tracking são já utilizadas na rotina da prática clínica, existindo diversos estudos que comprovam o seu valor e eficácia. Durante a última década estas ténicas têm vindo também a ser estudadas em Medicina Veterinária, sendo o Speckle tracking bi-dimensional considerado o mais recente. Tanto o Doppler Tecidular como o Speckle Tracking fornecem novos parâmetros de avaliação da performance do miocárdio, como a avaliação dos parâmetros de deformação (Strain e Strain Rate), torsão ventricular e sincronia mecânica do miocárdio. Nesta revisão será dada relevância às alterações destes parâmetros no estudo do ventrículo esquerdo. Desta forma, esta revisão tem como objectivo reunir os estudos feitos recentemente em diversas cardiopatias, assim como em animais saudáveis, podendo estes servir como referência na validação futura dos parâmetros de deformação. Será dado maior relevo à capacidade destas técnicas detectarem alterações precocemente, possibilitanto ao clínico uma conduta terapêutica adequada, antes dos parâmetros obtidos na ecocardiografia convencional se apresentarem alterados. Este factor é de extrema importância para o desenvolvimento da abordagem terapêutica quer no prognóstico quer no diagnóstico definitivo das cardiopatias em Medicina Veterinária.

碩士
中華大學
機械工程學系碩士班
101
For the occupational noise, there are laws and regulations, anti-noise protection with the right to wear, but not the size of the ear canal for domestic labor domestic and match the right earplug, resulting in domestic labor is often due to wear earplugs to produce comfort, but do not want to wear endless making further noise to hearing loss risk at work, Therefore, this study will start with the noise more workplace labor external ear canal measurement, thereby establishing a database of domestic labor external auditory canal measurement, and wear in one ear, one ear without wearing the ear external ear canal shape change measurement and data collection for the human ear by ear plugs to wear through a subjective questionnaire survey, as well as objective type of measurement to wear earplugs, canal wall pressure set to wear anti-noise earplugs comfort of performance indicators, and hope that through this survey to enhance the earplug comfort, wear a willingness to raise labor population.. In finite element analysis, the loading condition is the standard displacement level 1.2 cm. The analysis is performed loading-displacement 0.1 cm to 1.2 cm when the pressure inside the ear canal. Analog vivo canal pressure values and calculated pressure sensing value compared with each other authentication. According to FEA results, conclusions the comments can be addressed as follows: (1) Young's modulus of the material properties on the ear is not much affected, the earplug into the ear canal, 1.2 cm, the Young's coefficient of 32 MPa and 1260 MPa, the pressure difference between the results of 13 % to prove Young's coefficient is relatively small for the ear canal pressure has slowed the phenomenon; (2) The market earbud size number A, B, C, D, results from the pressure of the ear size of minimum pressure D, in line with the expectations, the load displacement D number from 0.1 ~ 1.2 cm, respectively, pressure 0 psi, 0 psi, 0 psi, 0.01 psi, 2.61 psi, 4.93 psi, 5.71 psi, 8.05 psi, 11.41 psi, 23.2 psi, ear plugs into the ear canal displacement of 0.65 cm ~ 0.8 cm interval, the pressure is 0.01 psi ~ 4.93 psi range, the ear crossing is usually oval, but the closer the first curve, the shape of the ear canal gradually render round, thus determining the size of the earbuds design trends around a small, enclosed under a large, full-length is longer, the pressure inside the ear canal can improve the situation.

Seismic Hazard Analysis (PSHA), rather than the subjective methodologies that are currently used. This study focuses particularly in the definition of the seismic sources, through the seismotectonic zoning, and the determination of historical earthquake location. An important step in the Probabilistic Seismic Hazard Analysis consists in defining the seismic source model. Such a model expresses the association of the seismicity characteristics with the tectonically-active geological structures evidenced by seismotectonic studies. Given that most of the faults, in low seismic regions, are not characterized well enough, the source models are generally defined as areal zones, delimited with finite boundary polygons, within which the seismicity and the geological features are deemed homogeneous (e.g., focal depth, seismicity rate). Besides the lack of data (short period of instrumental seismicity), such a method generates different problems for regions with low seismic activity: 1) a large sensitivity of resulting hazard maps to the location of zone boundaries, while these boundaries are set by expert decisions; 2) the zoning cannot represent any variability or structural complexity in seismic parameters; 3) the seismicity rate is distributed throughout the zone and the location of the determinant information used for its calculation is lost. We investigate an alternative approach to model the seismotectonic zoning, with three main objectives: 1) obtaining a reproducible method that 2) preserves the information on the sources and extent of the uncertainties, so as to allow to propagate them (through Ground Motion Prediction Equations on to the hazard maps), and that 3) redefines the seismic source concept to debrief our knowledge on the seismogenic structures and the clustering. To do so, the Bayesian methods are favored. First, a generative model with two zones, differentiated by two different surface activity rates, was developed, creating synthetic catalogs drawn from a Poisson distribution as occurrence model, a truncated Gutenberg-Richter law as magnitudefrequency relationship and a uniform spatial distribution. The inference of this model permits to assess the minimum number of data, nmin, required in an earthquake catalog to recover the activity rates of both zones and the limit between them, with some level of accuracy. In this Bayesian model, the earthquake locations are essential. Consequently, these data have to be obtained with the best accuracy possible. The main difficulty is to reduce the location uncertainty of historical earthquakes. We propose to use the method of Bakun and Wentworth (1997) to reestimate the epicentral region of these events. This method uses directly the intensity data points rather than the isoseismal lines, set up by experts. The significant advantage in directly using individual intensity observations is that the procedures are explicit and hence the results are reproducible. The results of such a method provide an estimation of the epicentral region with levels of confidence appropriated for the number of intensity data points used. As example, we applied this methodology to the 1909 Benavente event, because of its controversial location and the particularly shape of its isoseismal lines. A new location of the 1909 Benavente event is presented in this study and the epicentral region of this event is expressed with confidence levels related to the number of intensity data points. This epicentral region is improved by the development of a new intensity-distance attenuation law, appropriate for the Portugal mainland. This law is the first one in Portugal mainland developed as a function of the magnitude (M) rather than the subjective epicentral intensity (Muñoz, 1974, Martin 1984; Lopez Casado et al. 1992; Sousa and Oliveira, 1997; Lopez Casado et al., 2000). From the logarithmic regression of each event, we define the equation form of the attenuation law. We obtained the following attenuation law: I=−1.9438 ln(D)+4.1Mw−9.5763 for 4.4 ≤ Mw ≤ 6.2 Using these attenuation laws, we reached to a magnitude estimation of the 1909 Benavente event that is in good agreement with the instrumental one. The epicentral region estimation was also improved with a tightening of the confidence level contours and a minimum of rms[MI] coming closer to the epicenter estimation of Kárník (1969). Finally, this two zone model will be a reference in the comparison with other models, which will incorporate other available data. Nevertheless, future improvements are needed to obtain a seismotectonic zoning. We emphasize that such an approach is reproducible once priors and data sets are chosen. Indeed, the objective is to incorporate expert opinions as priors, and avoid using expert decisions. Instead, the products will be directly the result of the inference, when only one model is considered, or the result of a combination of models in the Bayesian sense; ### Zonas sismogénicas e leis de atenuação para a análise probabilística da perigosidade sísmica em regiões de baixa deformação Resumo: O objetivo desta tese é de apresentar metodologias reprodutíveis na estimação probabilística da perigosidade símica (PSHA), em vez das metodologias subjetivas que são usadas atualmente. Este estudo concentra-se particularmente na definição das fontes sísmicas, através do zonamento sismotectónico, e a localização de sismos históricos. Uma etapa importante na estimação do PSHA é a de definir o modelo de fonte sísmica. Este modelo reflete a associação das características de sismicidade com as estruturas tectónicas ativas, evidenciada pelos estudos sismotectónicos. Dado que a maioria das falhas em regiões de baixa sismicidade não estão suficientemente bem caracterizadas, os modelos de fonte são geralmente definidos como zonas de fonte polígonais delineadas por limites finitos, dentro dos quais a actividade sísmica e as características geológicas são consideradas homogéneas (por exemplo, a profundidade focal e a taxa de sismicidade). Para além da falta de dados (curto período de sismicidade instrumental), este método cria diferentes problemas para as zonas de baixa sismicidade: 1) uma elevada sensibilidade dos mapas de perigosidade nos limites das áreas, sendo que estes limites são feitos por decisão de peritos; 2) o zonamento não representa a variabilidade ou a complexidade estrutural dos parâmetros sísmicos; 3) a taxa de atividade sísmica é distribuída para toda a área e perde-se a localização da informação crítica utilizada para o seu cálculo . Propomos um método alternativo para o modelo de zonamento sismotectónico, com três objetivos principais: 1) obter um método reprodutível que 2) preserve as fontes de informação e incerteza, de maneira a propagá-los (através das equações de predição do movimento do solo e dos mapas de perigosidade) e que 3) redefine o conceito de fonte sísmica para questionar o nosso conhecimento acerca das estruturas sismogénicas. Neste sentido, os métodos Bayesianos são previlegiados. Foi desenvolvido um modelo generativo com duas zonas, diferenciadas por duas taxas de atividade sísmica, criando catálogos sintéticos derivados de uma distribuição de Poisson (modelo de ocorrência), de uma lei de Gutenberg-Richter truncada (relação magnitude-frequência) e de uma distribuição espacial uniforme de epicentros. A inferência deste modelo permite-nos estimar o número mínimo de dados, nmin, exigido num catálogo de sismicidade para estimar com um certo nível de precisão a taxa de atividade sísmica de cada zona e a respectiva fronteira. Neste modelo Bayesiano a localização dos sismos é crucial. É, por isso, fundamental obter estes dados com a maior precisão possível. A principal dificuldade reside na redução da incerteza na localização dos sismos históricos. Propomos a utilização do método de Bakun e Wentworth (1997 ) para re-estimar a região epicentral destes eventos. Este método usa diretamente dados pontuais da intensidade em vez das isossistas desenhadas por peritos. A vantagem significativa da utilização directa dos dados pontuais de intensidade é a clareza do processo e a reprodutibilidade dos resultados. Os resultados deste método produzem uma estimativa do epicentro associado a níveis de confiança apropriadas para o número de dados utilizados. Como exemplo, aplicámos esta metodologia ao terramoto de Benavente (1909) devido à sua controversa localização e à forma particular das suas isossistas. Deste estudo resultou uma nova localização do sismo de Benavente em que o epicentro deste evento é expresso com níveis de confiança que estão relacionados com o número de dados de intensidade. A localização epicentral foi melhorado pelo desenvolvimento de uma nova lei de atenuação, adequado para Portugal continental. Esta lei é a primeira desenvolvida em termos de magnitude, em vez da subjetiva intensidade epicentral proposta por outros autores (Muñoz, 1974, Martin 1984; Lopez Casado et al. 1992; Sousa and Oliveira, 1997; Lopez Casado et al., 2000). A partir da regressão logarítmica de cada evento, obtivemos a lei de atenuação seguinte: I=−1.9438 ln(D)+4.1Mw−9.5763 para 4.4 ≤ Mw ≤ 6.2 Usando estas leis de atenuação, chegamos a uma estimativa da magnitude do sismo ocorrido em Benavente em 1909, que é semelhante à que foi obtida por via instrumental (Mw = 6.0). A estimativa da zona epicentral foi também melhorada com um aperto dos contornos de nível de confiança e um mínimo de rms [MI] que aproximando-se da estimativa epicentral obtida por Karnik (1969) à partir de dados instrumentais. Finalmente, este modelo de duas zonas será uma referência na comparação com outros modelos, que irão incorporar outros dados disponíveis no sentido de obter um melhor zonamento sismotectónico. Insistimos que esta abordagem é reprodutível, a partir do momento que a informação a priori e os dados são selecionados. Com efeito, foi feito um esforço para incorporar as opiniões de peritos como informação a priori, evitando, deste modo, o uso de decisões dos mesmos. Os resultados finais são directamente uma consequência de uma inferência, quer quando se considera um único modelo, quer quando se considera uma combinação dos modelos no sentido Bayesiano; Zones sismogéniques et lois d'atténuation pour l'évaluation de l'aléa sismique probabiliste dans les régions à déformation lente Résumé: L'objectif de cette thèse est d'introduire des méthodologies reproductibles dans le calcul d'aléa sismique probabiliste (PSHA), plutôt que les méthodologies subjectives qui sont actuellement utilisées. Cette étude se concentre particulièrement sur la définition des sources sismiques, à travers le zonage sismotectonique, et la détermination de la localisation des séismes historiques. Une étape importante de l'estimation probabiliste du l'aléa sismique (PSHA) consiste à définir le modèle de source sismique. Un tel modèle reflète l'association des caractéristiques de sismicité avec les structures de tectonique active, mise en évidence par les études sismotectoniques. Étant donné que la plupart des failles, dans les régions peu sismiques, ne sont pas assez bien caractérisées, les modèles de source sont généralement définies comme des zones-sources, délimitées avec des polygones à limites finies, à l'intérieur desquels la sismicité et les caractéristiques géologiques sont considérées homogènes (ex: profondeur focale, taux de sismicité). En plus du manque de données (courte période de sismicité instrumentale), une telle méthode génère différents problèmes pour des régions à faible sismicité: 1) une grande sensitivité des cartes d'aléa au niveau des limites de zones, alors que ces limites sont réalisés par des décisions d'experts; 2) le zonage ne permet pas de représenter la variabilité ou la complexité structurelle dans les paramètres sismiques; 3) le taux de sismicité est distribué à travers la zone et on perd la localisation de l'information déterminante qui a été utilisé pour son calcul. Nous proposons une méthode alternative pour modéliser le zonage sismotectonique, avec trois principaux objectifs: 1) obtenir une méthode reproductible qui 2) préserve l'information sur les sources et ses incertitudes, de façon à les propager (à travers les équations de prédiction du mouvement du sol, puis dans les cartes d'aléa) et qui 3) redéfini le concept de source sismique pour questionner nos connaissances sur les structures sismogènes. Dans ce but, les méthodes bayésiennes sont privilégiées. Un modèle génératif avec deux zones, différenciées par deux taux d'activité sismique surfacique différents, a été développé, créant des catalogues synthétiques tirés d'une distribution de Poisson comme modèle d'occurrence, d'une loi de Gutenberg-Richter tronquée comme relation magnitude-fréquence et une distribution spatiale uniforme. L'inférence de ce modèle nous permet d'estimer le nombre minimum de données, nmin, requis dans un catalogue de sismicité pour retrouver le taux d'activité de chacune des zones et la limite entre elles, avec un certain niveau de précision. Dans ce modèle bayésien, la localisation des séismes est primordiale. Par conséquent, nous devons obtenir ces données avec la meilleure précision possible. La difficulté principale réside dans la réduction de l'incertitude liée à la localisation des séismes historiques. Nous proposons d'utiliser la méthode de Bakun and Wentworth (1997) pour ré-estimer la région épicentrale de ces évènements. Cette méthode utilise directement les points de données d'intensité plutôt que les isoséismes, réalisés par des experts. L'avantage significatif de l'utilisation directe des points de données d'intensité est que la démarche est explicite et que les résultats sont reproductibles. Les résultats d'une telle méthode donnent une estimation de la région épicentrale avec des niveaux de confiance qui sont appropriés pour le nombre de points d'intensité utilisés. Comme exemple, nous avons appliqué cette méthodologie au séisme de Benavente (1909), en raison de sa localisation controversée et de la forme particulière de ses isoséimes. Une nouvelle localisation du séisme de Benavente a été présentée dans cette étude. La région épicentrale de cette évènement est exprimée avec des niveaux de confiance qui sont reliés au nombre de points de données d'intensité. Cette région épicentrale a été améliorée par le développement d'une nouvelle loi d'atténution, appropriée pour le Portugal continental. Cette loi est la première développée en fonction de la magnitude plutôt qu'en fonction de l'intensité épicentrale (Muñoz, 1974, Martin 1984; Lopez Casado et al. 1992; Sousa and Oliveira, 1997; Lopez Casado et al., 2000). À partir de la régression logarithmique de chaque évènement, nous avons obtenu la loi d'atténuation suivante: I=−1.9438 ln(D)+4.1Mw−9.5763 pour 4.4 ≤ M w≤ 6.2 En utilisant ces lois d'atténuation, nous atteignons une estimation de magnitude pour le séisme de Benavente (1909) qui est en accord avec la magnitude instrumentale. L'estimation de la région épicentrale a aussi été amélioré, avec un resserrement des contours de niveau de confiance et un minimum de rms[MI] se rapprochant de l'estimation d'épicentre de Kárník (1969). Finallement, ce modèle deux zones sera une référence dans la comparaison avec d'autres modèles, qui incorporerons d'autres données disponibles. Cependant, des améliorations futures sont nécessaires pour obtenir un zonage sismotectonique. Nous insistons sur le fait qu'une telle approche est reproductible, à partir du moment où les informations a priori et les données sont choisis. En effet, nous nous efforcerons d'incorporer les opinions d'experts comme information a priori, en évitant d'utiliser les décisions d'experts. Les résultats finaux seront directement le résultat de l'inférence, quand un seul modèle est considéré, ou le résultat d'une combinaison de modèles, au sens bayésien.

Dissertação de Mestrado em Mecânica dos Solos e Engenharia Geotécnica apresentada à Faculdade de Ciências e Tecnologia
Reservatório Cerro da Mina é um reservatório de águas industriais, parte do complexo mineiro de Neves-Corvo, ao sul de Portugal. Impermeabilizado a montante por uma membrana de PEAD e construído aproximadamente metade em enrocamento e metade em rocha escavada, esta barragem esteve sujeita a três momentos de assentamento abruptos no aterro nos seus primeiros anos de operação. Este comportamento levantou questões acerca da natureza dos movimentos e da possibilidade de algum problema inesperado. A análise dos dados de nove extensómetros e de um inclinómetro instalados na secção de maior altura do enrocamento, juntamente com a avaliação das condições ambientais nos períodos em causa, revelaram que os deslocamentos significativos e inesperados coincidiram com períodos de intensa pluviosidade e subida no nível de água no reservatório. Tanto as deformações verticais como as horizontais apresentaram tendência de aumento acelerado sempre que um novo máximo no histórico de precipitações era registrado. O comportamento observado sugere que o aumento da humidade nos vazios do enrocamento gera uma redução significativa nos valores de sucção nos poros dos elementos rochosos, causando colapsos induzidos por molhagem no enrocamento. Além disso, os dados de observação indicam uma reduzida influência da oscilação do nível de água no reservatório na direção vertical, descartando este fator como causa principal dos assentamentos no enrocamento. As taxas de deformações verticais a longo prazo foram calculadas e apresentaram tendência similar ao previsto para este tipo de estrutura, não demonstrando sinais de problema neste sentido.
Reservatório Cerro da Mina is an industrial water reservoir part of Neves-Corvo mining compound, in the south of Portugal. Covered by an upstream impervious HDPE membrane and constructed approximately half on rockfill embankment and half on excavated rock, this dam experienced three moments of abrupt settlements on its embankments in the first years of operation. This behaviour raised concerns regarding the nature of the movements and the possibility of unanticipated problems. The analysis of the data from nine extensometers and one inclinometer installed in the highest section of the rockfill embankment, along with the assessment of the environmental conditions in the periods of interest, revealed that these significant unexpected vertical displacements coincided with periods of intense rainfall and rise in the water level in the reservoir. Both vertical and horizontal deformations of the rockfill showed a tendency of sudden increase when a new maximum in the precipitation record occurred. This represents an indication that the increase in humidity in the rockfill voids led to a significant decrease in the rock pore suction, causing wet-induced collapses in the rockfill. Additionally, the influence of the oscillation of the water level reservoir was estimated very small in the vertical direction, rejecting this factor as a major source of settlements in the rockfill. Long-term vertical deformation rates in the rockfill were calculated and presented a tendency fairly similar to what is expected for the kind of construction, showing no evidences of problems in that matter.

博士
國立臺灣科技大學
機械工程系
107
In this work, heat treatment (homogenization and ageing heat treatment processes) and extrusion plus A route type equal channel angular pressing (ECAP) severe plastic deformation methods were used to improve the microstructural and mechanical properties of as-cast SiCp/AZ61 magnesium metal matrix composites (Mg MMCs) fabricated by stir casting method. Different weight percentages (0%, 2% and 5%) of SiC particles (SiCp) were considered to study the effects of contents of reinforcements at different treatment conditions. Microstructural changes due to heat treatment processes, the number of ECAP passes and SiCp weight percentages were assessed using optical microscope (OM), scanning electron microscope (SEM), microhardness test and X-ray diffraction (XRD) patterns analysis. Enhanced mechanical properties were analyzed based on the Charpy impact and the uniaxial tensile test data. Furthermore, the brittle-ductile properties were testified by using scanning electron microscopy (SEM) features of Charpy impact and tensile test fracture surfaces. The work-hardening behavior of AZ61 magnesium alloy and SiCp/AZ61 Mg MMCs deformed by ECAP plastic deformation were studied by considering strain hardening rate (θ). The details of plastic deformation mechanisms and plastic deformation stages were identified by using a Crussard-Jaoul method based on the Ludwik equation. The response surface methodology in the design of experiments (DOE) wizard and Gurson-Tvergaard-Needleman (GTN) model were employed to estimate the optimum GTN damage parameters and to validate their significant effects respectively on the ductile fracture behavior of ECAP deformed AZ61 magnesium alloy. Hollomon flow stress was applied to identify uniform deformation and non-uniform deformation regions to investigate the void nucleation and coalescence processes separately. From the results obtained, ageing heat treatment process was seen significant on the 12 h aged 2 wt% SiCp/AZ61 Mg MMC which induced lower microhardness values and results in the formations of particle free regions and discontinuous secondary phases. At a higher number of ECAP passes and higher SiCp weight percentage, higher elastic modulus was seen enhanced. The strength, ductility and work-hardening behaviors were varied for both ECAP plastic deformation and SiCp weight percentage variations. The results of ductile fracture behavior of ECAP deformed AZ61 magnesium alloy showed that varying both stress triaxiality and damage variables simultaneously can greatly affect the curve fitting process of experimental, simulation and GTN model curves. The main contribution of this research work is enhancing the mechanical properties of SiCp/AZ61 Mg MMCs by modifying the presence and amount of microstructural constituent phases and by improving their uniform distribution.

MYOCARDIAL DEFORMATION AFTER ACUTE MYOCARDITIS WITH INFARCT-LIKE PRESENTATION. A 2-D STRAIN FOLLOW-UP STUDY Abstract BACKGROUND: The aim of present study was to assess left ventricular (LV) myocardial deformation and over-time changes in patients with acute myocarditis (AM) with infarct-like presentation. METHODS : 35 male patients with diagnosis of AM with preserved systolic function on the basis of cardiac magnetic resonance imaging (MRI) were prospectively enrolled. On admission, echocardiography with measurement of global longitudinal (LS), circumferential (CS) and radial (RS) strains, was performed both at endocardial (ENDO) and epicardial (EPI) levels. Findings were compared to 25 control subjects. RESULTS : Twenty-six patients were also monitored over a 22-month follow-up (FU group). On admission global ENDO-LS was poorer in AM (-19.2±3.1) than in controls (-24.0±1.05) (p<0.0001), whereas EPI-LS was not different (-20.6±3.4 vs -19.7±6, respectively, p=NS). A functional increase in both ENDO-LS (-20.8±5.4, p=NS) and EPI-LS (-22.6±4.6, p=0.02) was found in FU versus AM patients. EPI-CS also improved from -8.9±2.2 to -10.7±2.3 (p<0.0001), as well as ENDO-CS (from -21.4±4.2 to -23.3±4.9, p=0.001), whereas RS remained unchanged. Strain values were chiefly impaired in segments showing late gadolinium enhancement on admission cardiac MRI. CONCLUSIONS: The present study demonstrates a steady ENDO-LS impairment in infarct-like AM during a two-year follow-up period, despite preserved LV ejection fraction. This is more likely in segments showing gadolinium enhancement. On the contrary, EPI-LS, EPI-CS and ENDO-CS tend to improve as potential compensatory mechanisms.

In order to improve gas turbine performances, the operating temperature has been risen significantly over time. The possibility of applying more and more extreme operating conditions is mainly due to an efficient engine cooling. Secondary air system (SAS) design aims at obtaining the maximum efficiency with the minimum demand of mass flow bled from the compressor. Adequate cooling strategies have to be developed in order to guarantee suitable components lifespan and avoid failures. Anyway mass flows and pressure drops inside the secondary air system depend on the fluid-solid heat transfer itself, and in particular on the actual running clearances and gaps determined by the thermal expansion of components according to the current thermo-mechanical loads to which the engine is subjected. Due to changes in power generation market, the relevance of these issues increased considerably for large power generation gas turbines. In recent years their operating conditions have been deeply modified since more frequent and fast startups and shutdowns are required to meet electric load requirements. In order to manage thermal and mechanical stresses encountered in these repeated transient operations, and in order to monitor a number of parameters which should remain inside the pre-established operating ranges, the capability of predicting the thermal state of the whole engine represents a crucial point in the design process. Accurate prediction tools have to consider the strongly coupled phenomena occurring among SAS aerodynamic, metal-fluid heat transfer and deformations of the solid, in order to correctly estimate gaps and develop adequate SAS configurations. According to this, a Whole Engine Modelling (WEM) approach reproducing the entire machine in the real operating conditions is necessary in order to verify secondary air system efficiency, actual clearances, temperature peaks, structural integrity and all related aspects. It is here proposed a numerical procedure, developed in collaboration with Ansaldo Energia, aimed to perform transient thermal modelling calculations of large power generation gas turbines. The aerodynamic solution providing mass flows and pressures, and the thermo-mechanical analysis returning temperatures and material expansion are performed separately. The procedure faces the aero-thermo-mechanical problem with an iterative process with the aim of taking into consideration the mutual interaction of the different solutions, in a robust and modular analysis tool, combining secondary air system, thermal and mechanical analysis. The heat conduction in the solid and the fluid-solid heat transfer is computed by a customized version of the open source FEM solver CalculiX. The secondary air system is modelled by a customized version of the native CalculiX one-dimensional fluid network solver. Correlative and lower order methodologies for the fluid domain solution allows to speed up the design and analysis phase, while the presence of the iterative process allows to take into account the complex aero-thermo-mechanical interactions actually characterizing a real engine. A detailed description of the procedure will be reported with comprehensive discussions about the main fundamental modelling features introduced to cover all the aspects of interest in the simulation of a real machine. In order to assess the physical coherence of these features the procedure has been applied to two different test cases representative of typical real engine configurations, tested in a thermal transient cycle. The first one represents a simplified gas turbine arrangement tested with the aim of a first assessment from the point of view of the thermal loads evaluation. The second one is a portion of a real engine representative geometry, tested for the assessment of the interaction between SAS properties and the geometry deformations.

Over the last few decades, Canada has become a culturally diverse society. It is now commonplace for nurses to care for clients from cultures different from their own. Caring for culturally diverse clients present unique challenges to nurses. These clients often do not speak English and come to the hospital setting with varying health beliefs and customs. Furthermore, the challenge of caring for culturally diverse clients may uncover feelings in nurses about various ethnic groups. While there is an encouraging trend to include cultural content in nursing curricula, the effectiveness of nursing programs in preparing nurses to care for culturally diverse clients is not known . Additionally, there is evidence to suggest that culturally diverse clients may receive a lower standard of nursing care that might be explained by factors such as the nurse's knowledge, previous contact with ethnic minorities, attitudes, education, support, and the hospital setting. Few studies about nurses' experiences of caring for culturally diverse clients have been found. The purpose of this study was to explore the descriptions of recently graduated nurses of their experiences of caring for culturally diverse clients and to thereby gain an understanding of both the nature of the experience and any factors influencing the experience. A descriptive-exploratory design in the qualitative (naturalistic) tradition was selected to address the Level 1 question. The design took some direction from the phenomenological objective about understanding lived experience, but broadened that perspective to focus upon the shared elements within the specific experience of caring for culturally diverse clients. Eight recently graduated nurses were each interviewed twice. Data analysis proceeded simultaneously with the interviews through a process of constant comparative analysis. The conceptual structure that emerged from the thematic analysis was validated with the participants during the second interviews. The findings of the study revealed the experience of caring for culturally diverse clients as one of considerable complexity and persistent challenge. On the basis of the participants' varied descriptions, the nurses were conceptualized on a continuum of commitment to cross-cultural nursing, ranging from being resistant to being competent to being impassioned. While the nurses demonstrated a propensity to practice from a particular position on the continuum, their level of commitment at any given point might be influenced by personal or contextual factors that moved them toward either end of the continuum. Notably, the impassioned nurses all described an experience of awakening to the complex imperative of cross-cultural nursing that came out of specific situations in which they were sensitized to the minority experience. In order to provide culturally sensitive care, the participants implemented creative and flexible efforts in connecting with the client, working with the family, accommodating for cultural practices, and balancing expectations. The nature of the experience for the nurse and the quality of care provided to culturally diverse clients was also influenced by certain contextual factors, or catalysts, beyond the control of the nurse. The catalysts identified were the setting of health care, the support of colleagues, the commitment of the institution, and the foundation of education. Most significantly, the study uncovered the presence of racism in health care settings. The most obvious examples of racism came in the descriptions by the participants of the resistant nurses who were not represented in the sample. Other examples included inequities at the institutional level. In light of these findings, implications for education, administration, practice, research, and public policy were identified.

Many diseases such as cancer are initiated in single cells which modify their functions and amplify certain biological activities of the normal cells. These changes affect and permanently change the mechanical properties of normal cells. The significant difference between mechanical properties of different malignant cell lines could be used as a label free biomarker to distinguish between invasive and non-invasive carcinoma cells whose shapes and sizes are roughly the same. Among recent experimental methods for single cell assessments, dielectrophoresis (DEP) based devices have been introduced as novel techniques to direct deformation measurement of the living cell. In this work the application of microdevices for trapping and stretching of two human breast carcinoma cell lines based on dielectrophoresis phenomena, is presented. The results of electro-deformation process of two malignant cell lines, MDA-MB-231 (highly metastatic human breast carcinoma cell line) and MCF-7 (weakly metastatic human breast carcinoma cell line) using a positive DEP micro-device is presented in this work. The elastic constants of cells are measured by comparing the results of finite element simulation using COMSOL multiphysics with those of experimental studies. Concurring with the previous works, the results of this study show that highly metastatic breast cancer cells (MDA-MB-231) are much softer than weakly metastatic breast cancer cells (MCF-7), such that they could squeeze easier and migrate into human tissue through capillary blood vessels. An improved design to trap the suspended living cells in the middle of electrodes is presented and experimentally tested in the thesis. Inducing symmetric elongation on cells could improve the accuracy of calculated elastic constant of cells. Also, as the cells are positioning between electrodes (in the transparent zone) the visibility of captured images and accuracy of calibrated images could be improved.

Dissertação de Mestrado em Mecânica dos Solos e Engenharia Geotécnica apresentada à Faculdade de Ciências e Tecnologia
O aumento da população nos grandes centros das cidades resultou em uma maior demanda para os sistemas de trânsito. A utilização de túneis foi mostrado como uma ótima solução para melhorar essa crescente demanda por transporte. No entanto, seu uso pode induzir movimentos significativos na superfície do solo, o que pode danificar estruturas localizadas nas proximidades. Existem várias técnicas desenvolvidas para mitigar a magnitude desses movimentos. O objetivo deste estudo é focar em uma medida de mitigação: o uso de cortinas no solo para um caso de um túnel superficial. Tendo como referência o caso da Secção 63 da Linha Verde da rede do Metro de Lisboa, foram realizadas análises numéricas utilizando o software RS2 v2019, assumindo condições de deformação plana. Um estudo paramétrico foi realizado alterando a localização, profundidade e rigidez da cortina. A influência do fator de alívio do estresse em sua eficiência também foi investigada e discutida. Duas relações sem dimensões (local e global), os parâmetros de eficiência, foram empregados para avaliar o desempenho da cortina. A magnitude do impacto da cortina no suporte do túnel também foi investigada. A capacidade da cortina em modificar os assentamentos na superfície de forma favorável foi observada neste estudo específico. Além disso, foi observado um impacto quase insignificante nas forças que atuam no suporte do túnel.This dissertation incorporates 7 chapters:Chapter 1 is an introductory chapter that brings attention to the unavoidable growth of traffic rates in city centres. It highlights that tunnelling is a solution in the modern world to expand mass transportation. However, it also describes the consequences of tunnelling in heavily dense areas by describing three case histories. Among these, two of them suffered a visible impact, while the other one mitigation measures were taken in order to protect the structure. Chapter 2 gives an overview of terms and explanations of general considerations for short-term ground movements for shallow tunnels in soft ground. It depicts two conventional tunnelling methods in urban areas. It reviews the empirical methods from the literature employed to estimate displacements induced by tunnelling. Broadly, this chapter explores some mitigation measures typically taken to mitigate ground movements induced by tunnelling by giving some examples of applications in the past. Chapter 3 gives a concise bibliography review of studies performed and describes three case histories of using an embedded wall as a mitigation measure of settlements on the ground surface. It also describes in details two reference studies, Bilotta (2008) and Rampello et al. (2019) that this mitigation technique was employed. It explores and discusses the results of centrifuge tests and numerical analyses. Additionally, it describes the use of two dimensionless parameters termed as local and global efficiency to assess the efficacy of the embedded wall in mitigating settlements behind it. The results obtained and the suggestions made from the two studies were discussed and criticized. Chapter 4 presents the case of study of this dissertation, section 63, which is located between “Cais do Sodre” and “Baixa-Chiado” stations, from the Greenline Lisbon metro network. It briefly describes the background history and reviews with the evolution over time of the metro lines construction. It also describes the construction method employed. The geological and geotechnical conditions from this section are also discussed by describing the instrumentation survey and monitoring plan performed in the field between sections P4 and P13 (instrumented sections within section 63) Chapter 5 is dedicated to exploring in details the influence of using an embedded wall in the settlement trough by a two-dimensional finite element analysis by using RS2 v2019 software. It describes how the numerical analysis was performed in greenfield, and in the presence of the embedded wall (reference model) for the instrumented section P9. The general conditions of the study, the geometry of the problem, the mesh, the boundary conditions, the constitutive model, the construction sequence, and the geotechnical parameters adopted also are described. It is included the calibration of the numerical model in order to replicate the instrumented sections P9 and P10A, which involves the stress relief methodology based on the reference results measured in the field. The forces mobilised along the tunnel lining and the embedded wall are also depicted. This chapter also studies the efficiency of the wall by using a local efficiency parameter and describes the implementation of an additional methodology by using a dimensionless parameter that involves assessing the global efficiency of the embedded wall in the settlement trough.Chapter 6 describes three parametrical studies performed in this investigation by exploring the main factors that could affect the performance of the embe
This dissertation incorporates 7 chapters:Chapter 1 is an introductory chapter that brings attention to the unavoidable growth of traffic rates in city centres. It highlights that tunnelling is a solution in the modern world to expand mass transportation. However, it also describes the consequences of tunnelling in heavily dense areas by describing three case histories. Among these, two of them suffered a visible impact, while the other one mitigation measures were taken in order to protect the structure. Chapter 2 gives an overview of terms and explanations of general considerations for short-term ground movements for shallow tunnels in soft ground. It depicts two conventional tunnelling methods in urban areas. It reviews the empirical methods from the literature employed to estimate displacements induced by tunnelling. Broadly, this chapter explores some mitigation measures typically taken to mitigate ground movements induced by tunnelling by giving some examples of applications in the past. Chapter 3 gives a concise bibliography review of studies performed and describes three case histories of using an embedded wall as a mitigation measure of settlements on the ground surface. It also describes in details two reference studies, Bilotta (2008) and Rampello et al. (2019) that this mitigation technique was employed. It explores and discusses the results of centrifuge tests and numerical analyses. Additionally, it describes the use of two dimensionless parameters termed as local and global efficiency to assess the efficacy of the embedded wall in mitigating settlements behind it. The results obtained and the suggestions made from the two studies were discussed and criticized. Chapter 4 presents the case of study of this dissertation, section 63, which is located between “Cais do Sodre” and “Baixa-Chiado” stations, from the Greenline Lisbon metro network. It briefly describes the background history and reviews with the evolution over time of the metro lines construction. It also describes the construction method employed. The geological and geotechnical conditions from this section are also discussed by describing the instrumentation survey and monitoring plan performed in the field between sections P4 and P13 (instrumented sections within section 63) Chapter 5 is dedicated to exploring in details the influence of using an embedded wall in the settlement trough by a two-dimensional finite element analysis by using RS2 v2019 software. It describes how the numerical analysis was performed in greenfield, and in the presence of the embedded wall (reference model) for the instrumented section P9. The general conditions of the study, the geometry of the problem, the mesh, the boundary conditions, the constitutive model, the construction sequence, and the geotechnical parameters adopted also are described. It is included the calibration of the numerical model in order to replicate the instrumented sections P9 and P10A, which involves the stress relief methodology based on the reference results measured in the field. The forces mobilised along the tunnel lining and the embedded wall are also depicted. This chapter also studies the efficiency of the wall by using a local efficiency parameter and describes the implementation of an additional methodology by using a dimensionless parameter that involves assessing the global efficiency of the embedded wall in the settlement trough.Chapter 6 describes three parametrical studies performed in this investigation by exploring the main factors that could affect the performance of the embedded wall in the problem. In that, sixty-six numerical analyses were computed is investigated the influence of the location, depth, and stiffness of the embedded wall on local and global efficiency parameters. In addition to that, the impact of distinct stress relief factor on the efficiency parameters is explored. This chapter also explores and discusses the impact of using an embedded wall in the maximum forces acting along the lining. The forces induced along the embedded wall after the tunnel excavation is also investigated for a better understanding of the soil-structure interaction.Chapter 7 contains the conclusions and the main findings of the project. It considers how the project carried out varied from the previous studies performed. It also contains recommendations for future research.

Der untertägige Abbau von Steinkohle führt zu Bewegungen des überlagernden Gebirges und der Tagesoberfläche. Eine Bewegungsprognose ist im Hinblick auf entstehende Bergschäden weltweit von großer Bedeutung. In dieser Arbeit wird untersucht, ob eine Prognose von Bodenbewegungen im amerikanischen Steinkohlenbergbau mit einem in Europa bewährten Verfahren, einem dynamischen stochastischen Senkungsmodell, möglich ist. Dazu wurde eine Literaturstudie über den bisherigen Kenntnisstand in den USA durchgeführt, abbaubegleitende Bodenbewegungsmessungen aus dem Steinkohlengebiet der Appalachen ausgewertet und durch Modellrechnungen nachgebildet. Es wurde darüber hinaus untersucht, welchen Einfluss die spezifischen Abbaubedingungen und die räumliche und zeitliche Abbauführung auf die Größe und Dynamik von Bodenbewegungen haben. Die theoretischen und praktischen Untersuchungen zeigen einen deutlichen Know-how Vorsprung des europäischen Bergbaus in den Bereichen der Senkungsmodellierung und Bewertung abbauinduzierter Bodenbewegungen und belegen die Anwendbarkeit des Senkungsmodells. Es wurden wichtige Erkenntnisse gewonnen, die Möglichkeiten und Grenzen einer Optimierung des Abbauzuschnitts und der zeitlichen Abbauführung im Sinne einer bergschadensmindernden Abbauplanung aufzeigen. Die Arbeit trägt zur Verbesserung der bergmännischen und markscheiderischen Abbauplanung im Steinkohlenbergbau bei.