The heating of the solar corona has been investigated during four of decades and several mechanisms able to produce heating have been proposed. It has until now not been possible to produce quantitative estimates that would establish any of these heating mechanism as the most important in the solar corona. In order to investigate which heating mechanism is the most important, a more detailed approach is needed. In this thesis, the heating problem is approached ”ab initio”, using well observed facts and including realistic physics in a 3D magneto-hydrodynamic simulation of a small part of the solar atmosphere. The ”engine” of the heating mechanism is the solar photospheric velocity field, that braids the magnetic field into a configuration where energy has to be dissipated. The initial magnetic field is taken from an observation of a typical magnetic active region scaled down to fit inside the computational domain. The driving velocity field is generated by an algorithm that reproduces the statistical and geometrical fingerprints of solar granulation. Using a standard model atmosphere as the thermal initial condition, the simulation goes through a short startup phase, where the initial thermal stratification is quickly forgotten, after which the simulation stabilizes in statistical equilibrium. In this state, the magnetic field is able to dissipate the same amount of energy as is estimated to be lost through radiation, which is the main energy loss mechanism in the solar corona. The simulation produces heating that is intermittent on the smallest resolved scales and hot loops similar to those observed through narrow band filters in the ultra violet. Other observed characteristics of the heating are reproduced, as well as a coronal temperature of roughly one million K. Because of the ab initio approach, the amount of heating produced in these simulations represents a lower limit to coronal heating and the conclusion is that such heating of the corona is unavoidable.

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy applications in electric power systems. Growing demand for electrical energy and concerns associated with limited reserves of fossil fuels are also responsible for the development and increase in wind energy utilization. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix.<p> The contribution of wind farms to the overall system reliability is limited by the uncertainty in power output from the highly variable energy source. High wind penetration can lead to high risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The research work presented in this thesis is focused on developing reliability models for evaluating the benefits associated with wind power and energy storage in electric power generating systems. An interactive method using a sequential Monte Carlo simulation technique that incorporates wind farm and energy storage operating strategies is developed and employed in this research. Different operating strategies are compared and the resulting benefits are evaluated. Important system impacts on the reliability benefits from wind power and energy storage are illustrated. Hydro facilities with energy storage capability can alleviate the impact of wind power fluctuations and also contribute to system adequacy. A simulation technique for an energy limited hydro plant and wind farm coordination is developed considering the chronological variation in the wind, water and the energy demand. The IEEE four-state model is incorporated in the developed technique to recognize the intermittent operation of hydro units. Quantitative assessment of reliability benefits from effective utilization of wind and water resources are conducted through a range of sensitivity studies. The information provided and the examples illustrated in this thesis should prove useful to power system planners and wind developers to assess the reliability benefit from utilizing wind energy and energy storage and the coordination between wind and hydro power in electric power systems.

The ruins of the La Colle Falls Hydro Dam encompass two very distinct topographies: the physical landscape of the vast Canadian Northwest, and the complex emotional terrain of the urban mythology of the city of Prince Albert, Saskatchewan. In 1912 the city embarked on the ambitious project, building a dam and shipping lock on the North Saskatchewan River to supply the city with cheap and plentiful hydroelectric power and create a navigable inland shipping route from Winnipeg to Edmonton. The people of the community believed that it was poised to become a new commercial centre of the west, a key manufacturing and industrial metropolis. Instead, the project became an enormous and ruinous financial debacle that embarrassed the residents and crippled the urban growth of the city for nearly a century. Its failure, and the consequent suffering it brought permeate local legend to this day. The solution to this negative residual memory exists in the hydro dam’s own genesis: the spiritual and functional significance of the North Saskatchewan River as a site of traditional Aboriginal healing and a crucial regional amenity. Unable to bridle the waters of the North Saskatchewan, the dam instead comprises a dramatic visual testimony to the effects of an enormous work of construction on the panoramic Saskatchewan landscape, and an ideal setting to address the interface of man, structure, and the human body in the natural world. This thesis uses the ruins of the dam as a physical armature on which to construct a spa complex, an architectural insertion that will complete the dam, and present a positive alternative ending to its story. The spa is viewed as a place of intimate physical contact and remedial personal reflection that acknowledges the dramatic landscapes surrounding it, engages the senses, and simultaneously heals the bodies of the patrons while reconciling the latent negative historical memory of the original hydro dam project.

Ce mémoire procède à une analyse des avantages et des coûts, pour l'ensemble du Québec, d'un contrat à partage de risques établi sur une période de vingt-cinq ans entre une aluminerie et Hydro-Québec qui lui octroie une quantité substantielle d'électricité à faible tarif. L'hypothèse émise est que si ce contrat n'est pas renouvelé en 2014, l'aluminerie transfère sa production hors du Québec. Alors, la province subirait des pertes associées à l'arrêt de la production, mais en contrepartie, un bloc d'énergie deviendrait disponible pour le marché extérieur de plus en plus lucratif. Le modèle est basé sur des données publiées portant sur les ententes existantes et sur les alumineries du Québec. L'intérêt de l'évaluation est accentué par le contexte du marché de l'électricité. Le coût d'opportunité de la ressource grandit pendant que la demande interne et externe pour l'énergie est toujours en croissance. D'abord, un modèle caractérise les avantages pour la société québécoise que procure l'utilisation, pour la production d'aluminium, d'un bloc d'énergie de 5 Térawattheures. Cette valeur équivaut au produit marginal de l'électricité. C'est le coût éventuel du non-renouvellement du contrat. Ensuite, il est calculé le montant qui serait obtenu si ce même bloc d'électricité était alloué à l'exportation et si les revenus étaient réinvestis au Québec par la suite. Ce sont les bénéfices reliés au non-renouvellement du contrat. Une fois actualisée, la valeur des bénéfices soustraite de celle des coûts donne l'ordre de grandeur des pertes subies par l'ensemble de la société découlant de ces ententes. Elles sont évaluées entre 3 et 6 milliards de dollars. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Contrats à partage de risques, Hydro-Québec, Électricité, Aluminerie, Valeur ajoutée, Analyse avantages/coûts, Actualisation.

The ruins of the La Colle Falls Hydro Dam encompass two very distinct topographies: the physical landscape of the vast Canadian Northwest, and the complex emotional terrain of the urban mythology of the city of Prince Albert, Saskatchewan. In 1912 the city embarked on the ambitious project, building a dam and shipping lock on the North Saskatchewan River to supply the city with cheap and plentiful hydroelectric power and create a navigable inland shipping route from Winnipeg to Edmonton. The people of the community believed that it was poised to become a new commercial centre of the west, a key manufacturing and industrial metropolis. Instead, the project became an enormous and ruinous financial debacle that embarrassed the residents and crippled the urban growth of the city for nearly a century. Its failure, and the consequent suffering it brought permeate local legend to this day. The solution to this negative residual memory exists in the hydro dam’s own genesis: the spiritual and functional significance of the North Saskatchewan River as a site of traditional Aboriginal healing and a crucial regional amenity. Unable to bridle the waters of the North Saskatchewan, the dam instead comprises a dramatic visual testimony to the effects of an enormous work of construction on the panoramic Saskatchewan landscape, and an ideal setting to address the interface of man, structure, and the human body in the natural world. This thesis uses the ruins of the dam as a physical armature on which to construct a spa complex, an architectural insertion that will complete the dam, and present a positive alternative ending to its story. The spa is viewed as a place of intimate physical contact and remedial personal reflection that acknowledges the dramatic landscapes surrounding it, engages the senses, and simultaneously heals the bodies of the patrons while reconciling the latent negative historical memory of the original hydro dam project.

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy applications in electric power systems. Growing demand for electrical energy and concerns associated with limited reserves of fossil fuels are also responsible for the development and increase in wind energy utilization. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix.<p> The contribution of wind farms to the overall system reliability is limited by the uncertainty in power output from the highly variable energy source. High wind penetration can lead to high risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The research work presented in this thesis is focused on developing reliability models for evaluating the benefits associated with wind power and energy storage in electric power generating systems. An interactive method using a sequential Monte Carlo simulation technique that incorporates wind farm and energy storage operating strategies is developed and employed in this research. Different operating strategies are compared and the resulting benefits are evaluated. Important system impacts on the reliability benefits from wind power and energy storage are illustrated. Hydro facilities with energy storage capability can alleviate the impact of wind power fluctuations and also contribute to system adequacy. A simulation technique for an energy limited hydro plant and wind farm coordination is developed considering the chronological variation in the wind, water and the energy demand. The IEEE four-state model is incorporated in the developed technique to recognize the intermittent operation of hydro units. Quantitative assessment of reliability benefits from effective utilization of wind and water resources are conducted through a range of sensitivity studies. The information provided and the examples illustrated in this thesis should prove useful to power system planners and wind developers to assess the reliability benefit from utilizing wind energy and energy storage and the coordination between wind and hydro power in electric power systems.

Nonlinear coupling problems between the multiple bodies or between the mooring/riser and the offshore platform are incorporated in the CHARM3D-MultiBody, a fully coupled time domain analysis program for multiple bodies with moorings and risers. The nonlinear spring connection module and the three dimensional beam module are added to appropriately solve the structural connection problem. The nonlinear spring connection module includes the hydro-pneumatic tensioner module with the friction & stick/slip implementation, the tendon/mooring disconnection (breakage/unlatch) module with the tendon down-stroke check, and the contact spring with the initial gap with the friction force implemented. The nonlinear coupling may happen in many places for the offshore floating structures, such as hydro-pneumatic tensioner, tendon of TLP down stroke at the bottom joint, stick-slip phenomena at the tie down of the derrick and most of the fender-to-steel or steel-to-steel contact problem with initial gap during the installation. The mooring/tendon broken and unlatch can be a nonlinear connection problem once the transient mode is taken into account. Nonlinearity of the stiffness and friction characteristics of the tensioner combined with stick-slip behavior of riser keel joint is investigated. The relationship between tensions and strokes for hydro-pneumatic tensioner is based on the ideal gas equation where the isotropic gas constant can be varied to achieve an optimum stroke design based on tensioner stiffness. A transient effect of tendon down-stroke and disconnection on global performance of ETLP for harsh environmental condition is also investigated by incorporating the nonlinear boundary condition of the FE tendon model in CHARM3D. The program is made to be capable of modeling the tendon disconnection both at the top and the bottom connection as well as the down stroke behavior for the pinned bottom joint. The performance of the tie-down clamp of derrick is also investigated by using six degrees of freedom spring model and the three(3) dimensional FE beam model. The coupling of the TLP motion with the reaction force at the tie-down clamp is considered by using exact nonlinear dynamic equations of the motion with the reaction forces modeled with the spring or FE beam model. The method reduces too much conservatism when we design the tie-down system by the conventional method, in which all the environmental forces are combined without the phase lag effect between them. The FE beam model is also applied to the connectors between the semisubmersible and the truss for the pre-service and in-place conditions to be verified with the model test results, which shows good agreements.

The tube hydro-forming (THF) is an innovative manufacturing process which is used to manufacture many industrial components widely. The success of THF is largely dependent on the selection of the loading paths: internal pressure versus time, axial feeding versus time and counter punch (CP) versus time. The finite element analysis is used to simulate the forming result of different loading paths and reduce the cost of die-testing. This paper presents the forming of T-branches and T-branches components with CP. These paper has developed an adaptive simulation algorithm by combining FEM code LS-DYNA 3D with controller subroutine to get ideal bulging height and uniform thickness of the formed tube with multi-stages. Discuss influence under different parameters of process. The results are compared with experimental results to validate accuracy by this adaptive control methods.

Feasibility studies concerning decision-making for various types of items to be used in a small hydropower scheme is important for estimating the energy generation, the approximate cost of the project, and the required budget allocation. A computer program named RETScreen, which is commonly used in the North Americas, is capable of evaluating the energy generation, investment and maintenance costs for small hydro-projects. This thesis is based on application of this program to the Turkish practice. To this end, energy and cost equations dealing with energy generation and cost estimation of various items, such as costs of turbines, generators, installation of energy equipment, transmission line, etc., will be applied according to the common practice currently used in Turkey. A case study is performed to illustrate the use of this program. With the use of this program, it may be possible to perform quick successive runs to assess economic feasibility of several alternatives.

ABSTRACT The objective of this study is to establish the Forming Limit Diagram (FLD) of tubes. An experimental system of tube hydroforming, the electrical chemical etching method and the image process system are used to carry out the sheet metal forming test and the hydraulic bulge-forming test of annealed aluminum alloy tubes. Furthermore, Hill¡¦s new yield criterion is also used to predict the Forming Limit Curves of sheets. The predicted forming limit diagrams are compared with experimental data. The forming limit diagrams of tubes are coincident with those of sheets. Also, the predicted forming limit curves by Hill¡¦s new yield criterion agree quite well with those by experiments. Therefore, Hill¡¦s new yield criterion can be used to establish the forming limit curves of sheets or tubes.