The current standard of simulating flood flow in natural river reaches is based on solving the 1-D or 2-D St. Venant equations or using hybrid 1-D/2-D models based on the same equations. These models are not always able to accurately predict floodwave propagation, especially around and downstream of regions where 3-D effects become important, or at times when the main assumptions associated with these models are violated (e.g. flow becomes pressurized due to presence of a hydraulic structure like a bridge or a culvert). A 3-D modeling approach, though computationally much more expensive, is not subject to such limitations and should be able to predict accurately predict floodwave propagation even in regions where 3-D effects are expected to be significant. This dissertation describes the development and validation of a 3-D time-accurate RANS-based model to study flood-related problems in natural environments. It also discusses how results from these 3-D simulations can be used to better calibrate lower order models. Applications are included where the flow becomes pressurized during high flow conditions and the sediment entrainment potential of the flow during the flooding event is estimated. Another important category of applications discussed in the present study are floodwave propagation induced by a sudden dam break failure. Results show that 2-D models show fairly large differences with 3-D model predictions especially in regions where 3-D effects are expected to be significant (e.g. near channel-floodplain transition, in highly curved channels, near hydraulic structures). The study also discusses the use of the validated 3-D model as an engineering design tool to identify the optimum solution for flood protection measures intended to reduce flooding in the Iowa River near Iowa City. 3-D simulation results are also used to discuss hysteresis effects in the relationship between bed shear stress and the stage/discharge. Such effects need to be taken into consideration to accurately estimate erosion associated with the passage of a floodwave.

This dissertation presents a study on the development of a numerical model aimed at simulating free surface flow, which still remains an active research area. Modeling these processes is very challenging since the interface between air and water is characterized by sharp discontinuities in fluid properties and flow characteristics due to different densities, viscosities, surface tension and consequent discontinuities in spatial gradients of velocity and pressure. The constraint of incompressibility poses another difficulty on the efficient design of algorithms. Recently, the level set method has emerged as a powerful tool for evolving interfaces in computational science and engineering for a wide range of applications while the finite element method has been long known for its geometrical flexibility. An effort to combine these two methods is made in this study. Several benchmark problems are used for the test of the developed code in view of temporal and spatial accuracy. Then, the capability and efficiency of the model are extended with advanced turbulence models and parallel algorithm. The model is applied to problems of practical importance in hydraulics, including hydraulic jump under a sluice gate and the design of spillways for fish migration. The main focus is on the capturing of free surface and identifying and understanding of the vortical structures and nonhydrostatic pressure distribution. The model has proved to be very effective for these purpose. The new technique dealing with air-water interface in a more physically accurate way is introduced for future development and the new method is applied to the problems of static equilibrium for validation.

Since the founding of the People’s Republic of China in 1949, China has experienced ten business cyclical fluctuations. The economic growth was characterized by erratic ups and downs which lasted for several decades. With the economic reform and opening up to the outside world in 1978 as part of Deng Xiaoping’s market-oriented policy, the Chinese economy grew exponentially and the volatility of the GDP growth rate declined significantly. The macroeconomic control policies in the 1980s prevented large fluctuations in the country’s economic development, and smoothed the output volatility further. This study examines the output volatility in China and our result reveals the standard deviation of quarterly output growth rate has declined dramatically. Using the CUSUM squares test and the Quandt-Andrews breakpoint test to identify unknown structure breaks, we identified two structural breaks: 1994:1 towards destabilization and 1998:1 towards stabilization. We then examine the stochastic process for GDP and the result shows that the decrease in volatility can be traced primarily to a decrease in the standard deviation of output shocks. Following this, we reached two other conclusions. First, there is a strong relationship between movements in output volatility and the movements in inflation volatility. Both output and inflation volatilities increased significantly during the third and fourth quarter of 1994 and both dropped sharply after 1996, which followed a similar path over the period. Second, using the standard decomposition of GDP, the decrease in output volatility can be traced to a decrease in the volatility of consumption, investment, and net export, especially rural consumption expenditure and residential investment.

<p>This paper presents the feasibility study of setting up the new potting tray production line based on the two alternatives: partly outsource a process in the production line or wholly make all processes in-house. Both the qualitative and quantitative approaches have been exploited to analyze and compare between the make or buy decision. Also the nature of business, particularly SMEs, in Thailand has been presented, in which it has certain characteristics that influence the business doing and decision, especially to the supply chain management. The literature relating to the forecasting techniques, outsourcing decision framework, inventory management, and investment analysis have been reviewed and applied with the empirical findings. As this production line has not yet been in place, monthly sales volumes are forecasted within the five years time frame. Based on the forecasted sales volume, simulations are implemented to distribute the probability and project a certain demand required for each month. The projected demand is used as a baseline to determine required safety stock of materials, inventory cost, time between production runs and resources utilization for each option. Finally, in the quantitative analysis, the five years forecasted sales volume is used as a framework and several decision making-techniques such as break-even analysis, cash flow and decision trees are employed to come up with the results in financial aspects.</p>

<p>Active safety systems for automobiles in the form of camera systems have evolved rapidly the last ten years, Autoliv Electronics in Linköping develops multiple such systems. In their development process there is a need for a Break out Box (BoB) to record and playback video and CAN data as if the camera system was used in an actual automobile. The aim of this thesis has been to develop a BoB for these camera systems. The work has been divided into three phases; identification of requirements, design of the BoB and implementation of a prototype. The project has addressed four known issues with the currently used BoB; bandwidth, modularity, synchronization and usability. The result is a new BoB which is based on an FPGA connecting to a PC over Gigabit Ethernet. The design is an extendible platform for multiple channels of video, CAN data, other serial data and future extensions. A prototype proves the design concept by successfully recording video for the Autoliv NightVision system onto a PC.</p>

In case of exceptional floods induced by the failure of a dam, huge amounts of sediments may be eroded. This results in large-scale modifications of the valley morphology and may drastically increase the resulting damages. The objective of the research is to advance the understanding of sediment transport under dam-break flows. For such highly erosive and transient floods, it is crucial to account explicitly for sediment inertia, and therefore traditional “clear-water” modelling approaches are largely inappropriate. The present approach relies on a two-layer idealisation of the flow behaviour. Separating a clear-water flow region from the underlying sediment bed, the transported sediments are confined in a flow layer of finite thickness, endowed with its proper inertia, density and velocity. The thesis also pinpoints granular dilatancy as an essential mechanism of interaction between the layers. When passing from a solid-like to a fluid-like behaviour as they are entrained by the flow, the eroded sediment grains dilate along the vertical, and this generates vertical exchanges of mass and momentum that should be accounted for. The thesis proceeds first with experimental investigations. Laboratory dam-break waves are reproduced in a dedicated flume, exploring different bed configurations and sediment densities. Imaging observations are used to support the proposed phenomenological description of the flow. Within a shallow-water framework, theoretical and numerical endeavours are then developed to investigate the implications on the flow dynamics of the two essential contributions of the proposed description, i.e. the two-layer flow behaviour, and the effects of granular dilatancy.

<p>Web breaks are considered as one of the most significant runnability problems</p><p>in a pressroom. This work concerns the analysis of relation between various</p><p>parameters (variables) characterizing the paper, printing press, the printing</p><p>process and the web break occurrence. A large number of variables, 61 in</p><p>total, obtained off-line as well as measured online during the printing process</p><p>are used in the investigation. Each paper reel is characterized by a vector x</p><p>of 61 components.</p><p>Two main approaches are explored. The first one treats the problem as a</p><p>data classification task into "break" and "non break" classes. The procedures</p><p>of classifier training, the selection of relevant input variables and the selection</p><p>of hyper-parameters of the classifier are aggregated into one process based on</p><p>genetic search. The second approach combines procedures of genetic search</p><p>based variable selection and data mapping into a low dimensional space. The</p><p>genetic search process results into a variable set providing the best mapping</p><p>according to some quality function.</p><p>The empirical study was performed using data collected at a pressroom</p><p>in Sweden. The total number of data points available for the experiments</p><p>was equal to 309. Amongst those, only 37 data points represent the web</p><p>break cases. The results of the investigations have shown that the linear</p><p>relations between the independent variables and the web break frequency</p><p>are not strong.</p><p>Three important groups of variables were identified, namely Lab data</p><p>(variables characterizing paper properties and measured off-line in a paper</p><p>mill lab), Ink registry (variables characterizing operator actions aimed to</p><p>adjust ink registry) and Web tension. We found that the most important</p><p>variables are: Ink registry Y LS MD (adjustments of yellow ink registry</p><p>in machine direction on the lower paper side), Air permeability (character-</p><p>izes paper porosity), Paper grammage, Elongation MD, and four variables</p><p>characterizing web tension: Moment mean, Min sliding Mean, Web tension</p><p>variance, and Web tension mean.</p><p>The proposed methods were helpful in finding the variables influencing </p><p>the occurrence of web breaks and can also be used for solving other industrial</p><p>problems.</p>

<p>The objective of this project is to study the production of Li, Be and B isotopes emitted in the interaction of 12C with 12C at incident energies of 200 and 400 MeV.<br /> The energies of these produced fragments were measured with a detector telescope consisting of two silicon detectors at the incident energy of 200 MeV while a third silicon detector was added for the measurements at 400 MeV.</p>

Tsunamis are among the most terrifying and complex physical phenomena potentially affecting almost all coastal regions of the Earth. Tsunami waves propagate in the ocean over thousands of kilometres away from their generating source at considerable speeds. Among several other tsunamis that occurred during the past decade, the 2004 Indian Ocean Tsunami and the 2011 Tohoku Tsunami in Japan, considered to be the deadliest and costliest natural disasters in the history of mankind, respectively, have hit wide stretches of densely populated coastal areas. During these major events, severe destruction of inland structures resulted from the action of extreme hydrodynamic forces induced by tsunami flooding. Subsequent field surveys in which researchers from the University of Ottawa participated ultimately revealed that, in contrast to seismic forces, such hydrodynamic forces are not taken into proper consideration when designing buildings for tsunami prone areas. In view of these limitations, a novel interdisciplinary hydraulic-structural engineering research program was initiated at the University of Ottawa, in cooperation with the Canadian Hydraulic Centre of the National Research Council, to help develop guidelines for the sound design of nearshore structures located in such areas. The present study aims to simulate the physical laboratory experiments performed within the aforementioned research program using a single-phase three-dimensional weakly compressible Smoothed Particle Hydrodynamics (SPH) numerical model. These experiments consist in the violent impact of rapidly advancing tsunami-like hydraulic bores with individual slender structural elements. Such bores are emulated based on the classic dam-break problem. The quantitatively compared measurements include the time-history of the net base horizontal force and of the pressure distribution acting on columns of square and circular cross-sections, as well as flow characteristics such as bore-front velocity and water surface elevation. Good agreement was obtained. Results show that the magnitude and duration of the impulsive force at initial bore impact depend on the degree of entrapped air in the bore-front. The latter was found to increase considerably if the bed of the experimental flume is covered with a thin water layer of even just a few millimetres. In order to avoid large fluctuations in the pressure field and to obtain accurate simulations of the hydrodynamic forces, a Riemann solver-based formulation of the SPH method is utilized. However, this formulation induces excessive numerical diffusion, as sudden and large water surface deformations, such as splashing at initial bore impact, are less accurately reproduced. To investigate this particular issue, the small-scale physical experiment of Kleefsman et al. (2005) is also considered and modeled. Lastly, taking full advantage of the validated numerical model to better understand the underlying flow dynamics, the influence of the experimental test geometry and of the bed condition (i.e. dry vs. wet) is investigated. Numerical results show that when a bore propagates over a wet bed, its front is both deeper and steeper and it also has a lower velocity compared to when it propagates over a dry bed. These differences significantly affect the pressure distributions and resulting hydrodynamic forces acting on impacted structures.

Maintenance of hematopoiesis depends upon rare hematopoietic stem cells (HSCs), which can persist over an organism’s lifetime. It is conceivable that they must maintain a high degree of genetic stability; otherwise recurring exposure to genotoxins and accumulation of genetic changes could result in genomic instability and malignancy or cell death. We have focused on the response of HSCs and primitive hematopoietic cells to highly toxic DNA double-strand breaks (DSBs). Using assays to detect break rejoining and kinetics of early DSB response foci, we determined that non-cycling human HSC-containing cells display delayed break rejoining kinetics and persistent γH2AX and 53BP1 foci compared to cycling counterparts, more differentiated hematopoietic cells and human primary fibroblasts. In contrast, when stimulated to cycle, these HSC-containing cells are quite efficient at repairing breaks and resolving foci. These data suggest that the DNA damage response may be unusually prolonged in non-cycling primitive hematopoietic cells.