In this study, a two phase investigation of the hydraulic conductivity parameters of silty soils was performed. In the first phase, double-ring infiltrometer tests were used to measure infiltration rates in-situ at two sites in the Piedmont physiographic province of Georgia. The efficacy of predicting saturated hydraulic conductivity for Piedmont soils via published soil surveys from the National Resource Conservation Service and pedotransfer functions was then investigated. Work focused on the development of a consistent test methodology for soils (sandy, to silts and clays) in the Piedmont, and the final test method utilized being the constant head test, using a double-ring infiltrometer with Mariotte tubes to maintain the head. In the second phase of the investigation, laboratory based measurements of the saturated hydraulic conductivity of binary mixtures of fine sand and nonplastic silt were performed to investigate the effects of particle mixtures on hydraulic conductivity. The materials used were ASTM 100/200 sand and Sil-Co-Sil 40 non-plastic silt, chosen based on the ratio of the mean particle diameters. Significant effort was invested in the development and comparison of methodologies to produce uniform specimens of the binary mixtures for hydraulic conductivity testing, with the final being modified dry tubing. Two fixed densities were used to investigate the effects of particle packing on the hydraulic conductivity of binary mixtures, with critical fines contents chosen to ensure the finer particles primarily filled the pore volume of the coarse particles. Incremental fines contents, by mass, up to this theoretical fines content were tested. The measured saturated hydraulic conductivity was evaluated in terms of fines content, global and intergranular void ratio, and confining stress. Models for predicting extreme void ratios and saturated hydraulic conductivity of binary mixtures were also investigated.

The flow of solid liquid mixtures (slurries) has attracted much attention in research work because of its importance to industry. Prediction of pressure losses associated with slurry flow helps pipe designers select the correct pipe sizes for optimum energy consumption, equipment sizing and reliable operation of the pipeline networks. Many workers developed empirical correlations, but due to the randomness of the problem they seem of limited use in design applications because they do not contain an assessment except by trial and error, which is costly. The existence of more than one particle size poses more complexities to the slurry flow problem but it is in need in practical applications. The aims of this work are justified under the light of the observations on the state of the art in slurry transport. An experimental program is designed to highlight the effects of this problem through a predetermined set of test runs. The variables are grouped to optimise the number of experiments and to remove the effect of dimensions on the prediction method The test rig is built to serve the aims of this exercise and test runs conducted, results grouped and discussed for polyfractional slurries. A mathematical model is developed in the form of an empirical correlation. Statistical tests are employed to verify the goodness of fit. Finally, conclusions and recommendations for further work are listed.

Whether it is a car, a mobile phone, or a computer, we are noticing how automation and production with robots plays an important role in the industry of our modern world. We find it in factories, manufacturing products, automotive cruise control, construction equipment, autopilot on airplanes, and countless other industrial applications.         Automation technology can vary greatly depending on the field of application. On one end, we have systems that are operated by the user and rely fully on human ability. Examples of these are heavy-mobile equipment, remote controlled systems, helicopters, and many more. On the other end, we have autonomous systems that are able to make algorithmic decisions independently of the user.         Society has always envisioned robots with the full capabilities of humans. However, we should envision applications that will help us increase productivity and improve our quality of life through human-robot collaboration. The questions we should be asking are: “What tasks should be automated?'', and “How can we combine the best of both humans and automation?”. This thinking leads to the idea of developing systems with some level of autonomy, where the intelligence is shared between the user and the system. Reasonably, the computerized intelligence and decision making would be designed according to mathematical algorithms and control rules.         This thesis considers these topics and shows the importance of fundamental mathematics and control design to develop automated systems that can execute desired tasks. All of this work is based on some of the most modern concepts in the subjects of robotics and control, which are synthesized by a method known as the Virtual Holonomic Constraints Approach. This method has been useful to tackle some of the most complex problems of nonlinear control, and has enabled the possibility to approach challenging academic and industrial problems. This thesis shows concepts of system modeling, control design, motion analysis, motion planning, and many other interesting subjects, which can be treated effectively through analytical methods. The use of mathematical approaches allows performing computer simulations that also lead to direct practical implementations.

The development of modern sailing boats has been based almost entirely on the cooperative efforts of enthusiastic skippers, designers and sail-makers, with very little contribution from scientists and technologists and using just basic scientific principles. In recent times, urgent and strong requests for improved performance, mostly for racing yachts, have guided the interest and the attention of the scientific community in the optimisation of sail performance and design approach. Sailing performance depends on the sailboat velocity, aerodynamic and hydrodynamic characteristics. This thesis focuses on the importance of the quantitative evaluation of the sail loads and how this contributes to the improvement of the performance of a sailboat through the development of a system for aiding sail design and assisting mast design. The objective of this study is to provide an integrated design system, which supplies analysis method and design features via a user-friendly graphical interface of a single-sail configuration. The major achievement is the development of an integrating numerical method, which evaluates loads and their distribution and the consequent deformed sail-shape. It improves sail performance analyses and design of new sails. Summarising, the major achievements are: • efficacy of accurate performance analysis for each sail, for any given shape over all the possible sailing courses; • critical investigation of the sail behaviour in the above-mentioned cases; improved approach to an integrated sail design; improvements in mast design from the structural and aerodynamic point of view; limited design costs, in terms of time consumed and computational power employed; efficacy of the visualisation of novel designed sail and predicted performance, which reduces the number of possible design flaws. hi conclusion, the integrated sail analysis and design system presented has important margins of improvements and diversification: extensions to non-homogeneous and anisotropic sailcloth, to two-sail configuration, windsurfs and integration of the mast.

Landfills are considered to be one of the major sources of anthropogenic methane (CH4) emissions in the environment. A landfill biocover system optimizes environmental conditions for biotic CH4 consumption that controls the fugitive and residual emissions from landfills. A compost material has more oxidation potential in comparison to any other material due to its high porosity, organic content, free flux for gases and water holding capacity. Thermal, hydraulic, bio – chemical and mechanical (THMCB) properties are important factors that can significantly affect the performance of biocover material with regards to CH4 oxidation potential as well as structural stability. Technical data on the thermal, hydraulic and mechanical (THM) properties of compost based biocover materials are quite limited. Hence, a detailed experimental program has been carried out at the University of Ottawa to study the THM properties and behaviour of compost biocover material by conducting experimental tests on small compost samples as well as by performing column experiments. The test results indicate that lower water content (dry of optimum for compaction curve) shows more free air space (FAS) in comparison to higher water content. The compost has almost the same shear strength for various initial water contents and dry unit weights; however, it settles and swells more at higher water content than lower water content per mechanical test results. The thermal and hydraulic properties of compost are a function of the compaction degree in addition to various other parameters. It is also found that the THM properties of compost are strongly coupled and the degree of saturation greatly affects the FAS.

This work is about fracture conductivity; how to measure and model it based on experimental data. It is also about how to determine the relative importance of the factors that affect its magnitude and how to predict its magnitude based on these factors. We dynamically placed the slurry hereby simulating the slurry placement procedure in a field-scale fracture. We also used factorial and fractional factorial designs as the basis of our experimental investigation. The analysis and interpretation of experimental results take into account the stochastic nature of the process. We found that the relative importance of the investigated factors is dependent on the presence of outliers and how they are handled. Based on our investigation we concluded that the investigated factors arranged in order of decreasing impact on conductivity are: closure stress, polymer loading, flow back rate, presence of breaker, temperature and proppant concentration. In particular, we find that at high temperatures, fracture conductivity was severely reduced due to the formation of a dense proppant-polymer cake. Also, dehydration of the residual gel in the fracture at high flow back rates appears to cause severe damage to conductivity at higher temperatures. This represents a new way of thinking about the fracture cleanup process; not only as a displacement process, but also as a displacement and evaporative process. In engineering practice, this implies that aggressive flow back schemes are not necessarily beneficial for conductivity development. Also, we find that at low proppant concentrations, there is the increased likelihood of the formation of channels and high porosity fractures resulting in high fracture conductivities. The uniqueness of this work is a focus on the development of a conductivity model using regression analysis and also the illustration of a procedure that can be used to develop a conductivity model using dimensional analysis. We reviewed both methodologies and applied them to the challenge of modeling fracture conductivity from experimental studies.

Hydraulic fracture conductivity in ultra-low permeability shale reservoirs is directly related to well productivity. The main goal of hydraulic fracturing in shale formations is to create a network of conductive pathways in the rock which increase the surface area of the formation that is connected to the wellbore. These highly conductive fractures significantly increase the production rates of petroleum fluids. During the process of hydraulic fracturing proppant is pumped and distributed in the fractures to keep them open after closure. Economic considerations have driven the industry to find ways to determine the optimal type, size and concentration of proppant that would enhance fracture conductivity and improve well performance. Therefore, direct laboratory conductivity measurements using real shale samples under realistic experimental conditions are needed for reliable hydraulic fracturing design optimization. A series of laboratory experiments was conducted to measure the conductivity of propped and unpropped fractures of Barnett shale using a modified API conductivity cell at room temperature for both natural fractures and induced fractures. The induced fractures were artificially created along the bedding plane to account for the effect of fracture face roughness on conductivity. The cementing material present on the surface of the natural fractures was preserved only for the initial unpropped conductivity tests. Natural proppants of difference sizes were manually placed and evenly distributed along the fracture face. The effect of proppant monolayer was also studied.

The underlying objective of this research is to improve the overall understanding of how spatial and temporal variability in macroporosity and soil hydraulic properties in the shallow subsurface influence the long term mobility of agricultural nutrients, and specifically the movement of liquid swine manure, in macroporous, tile drained soils. The principal motivation for the work was to provide insight into dynamic nutrient mobility in this type of agricultural environment in order to guide both the efficiency and environmental sustainability of nutrient management practices. The results of this work facilitate the advancement of our conceptual understanding and our ability to simulate preferential flow and transport in structured agricultural soils that are subject to seasonal hydrologic patterns similar to those found in the humid continental climate of southwestern Ontario

The automotive industry has been in a marathon of advancement over the past decades. This is partly due to global environmental concerns about increasing amount of air pollutants such as NOx (oxides of nitrogen), CO (carbon monoxide) and particulate matters (PM) and decreasing fossil fuel resources. Recently due to stringent emission regulations such as US EPA (Environmental Protection Agency) and CARB (California Air Resource Board), improvement in fuel economy and reduction in the exhaust gas emissions have become the two major challenges for engine manufacturers. To fulfill the requirements of these regulations, the IC engines including gasoline and diesel engines have experienced significant modifications during the past decades. Incorporating the fully flexible valvetrains in production IC engines is one of the several ways to improve the performance of these engines. The ultimate goal of this PhD thesis is to conduct feasibility study on development of a reliable fully flexible hydraulic valvetrain for automotive engines. Camless valvetrains such as electro-hydraulic, electro-mechanical and electro-pneumatic valve actuators have been developed and extensively studied by several engine component manufacturers and researchers. Unlike conventional camshaft driven systems and cam-based variable valve timing (VVT) techniques, these systems offer valve timings and lift control that are fully independent of crankshaft position and engine speed. These systems are key technical enablers for HCCI, 2/4 stroke-switching gasoline and air hybrid technologies, each of which is a high fuel efficiency technology. Although the flexibility of the camless valvetrains is limitless, they are generally more complex and expensive than cam-based systems and require more study on areas of reliability, fail safety, durability, repeatability and robustness. On the contrary, the cam-based variable valve timing systems are more reliable, durable, repeatable and robust but much less flexible and much more complex in design. In this research work, a new hydraulic variable valve actuation system (VVA) is proposed, designed, prototyped and tested. The proposed system consists of a two rotary spool valves each of which actuated either by a combination of engine crankshaft and a phase shifter or by a variable speed servo-motor. The proposed actuation system offers the same level of flexibility as camless valvetrains while its reliability, repeatability and robustness are comparable with cam driven systems. In this system, the engine valve opening and closing events can be advanced or retarded without any constraint as well as the final valve lift. Transition from regenerative braking or air motor mode to conventional mode in air hybrid engines can be easily realized using the proposed valvetrain. The proposed VVA system, as a stand-alone unit, is modeled, designed, prototyped and successfully tested. The mathematical model of the system is verified by the experimental data and used as a numerical test bench for evaluating the performance of the designed control systems. The system test setup is equipped with valve timing and lift controllers and it is tested to measure repeatability, flexibility and control precision of the valve actuation system. For fast and accurate engine valve lift control, a simplified dynamic model of the system (average model) is derived based on the energy and mass conservation principles. A discrete time sliding mode controller is designed based on the system average model and it is implemented and tested on the experimental setup. To improve the energy efficiency and robustness of the proposed valve actuator, the system design parameters are subjected to an optimization using the genetic algorithm method. Finally, an energy recovery system is proposed, designed and tested to reduce the hydraulic valvetrain power consumption. The presented study is only a small portion of the growing research in this area, and it is hoped that the results obtained here will lead to the realization of a more reliable, repeatable, and flexible engine valve system.

In this study underground dams are briefly described and detailed information about the design and construction aspects is provided. Since the material, of which dam wall is composed, is the main variable influencing the groundwater behavior, various types of dam wall are discussed. The use and usefulness of the underground dams as a means of sustainable development, and their performance in the management of groundwater resources are analyzed with the help of two example studies. In the first example a hypothetical idealized aquifer is considered, while in the second one, a real aquifer is selected. For the performance evaluation, and for the analysis of the impact of the underground dams on the groundwater behavior, numerical simulation is opted. For that purpose, a well-known computer code, MODFLOW, A Modular Three-Dimensional Finite Difference Groundwater Flow Model of U.S. Geological Survey, (McDonald and Harbaugh, 1988) is used.