kein Abstract vorhanden

Texte remanié de: Th. doct.--Éthique médicale--Paris 5, 2001. Titre de soutenance : Le malade, sa famille et les soignants en unité de soins palliatifs : étude psychopathologique, philosophique et éthique de leur relation : réflexion sur la relation soignants-familles des malades. / En appendic,e choix de documents. Bibliogr. p. 207-223.

Thèse de doctorat : Physique : Physique atomique et des collisions : Metz : 2007. / Thèse soutenue sur l'ensemble de travaux. Bibliogr.f. 94-95.

Liquid cooled small channel heat sinks have become a promising heat dissipation method for future high power electrical devices. Traditional mini and microchannel heat sinks consist of a single layer of low-aspect ratio rectangular channels. The alternative new heat sinks are fabricated by stacking many channels together to create multiple layer channels. These multilayer heat sinks can achieve high heat flux due to high heat transfer coefficients from small channels and large surface area from multilayer structure. In this research, multilayer copper and silicon carbide (SIC) minichannel heat sinks were tested in single-phase flow. It was shown that multilayer heat sinks have significant advantages over single-layer equivalents with reductions both in thermal resistance and pressure drop. A 3-D resistance network model for single and multilayered heat sinks was developed and validated. Parametric study and optimization on copper and SiC heat sinks with respect to channel geometries, number of layers, and heat sink conductivity were conducted by using the model.Both copper and SiC heat sinks were also tested in two-phase flow. In experiments, the multilayer copper heat sinks achieved smaller average surface temperature than their single-layer counterpart at low heat flux. However the multilayer copper heat sinks gradually lost stability at high heat flux, which lead to increased surface temperature. The redistribution of flow in different layers caused by pressure discrepancy in different layers was believed to be the cause. A three-zone model, which dividing the flow in small channels into three distinguishing parts: single-phase flow, subcooled boiling flow, and saturated boiling flow, was proposed to describe the different two-phase flow regimes. In each zone, the local heat transfer coefficient was computed by corresponding correlation. Several boiling correlations combined with the resistance network model were used to compute the heat sink surface temperature distributions, which were compared with experimental results. It was found the classical boiling correlations for macro channels are not suitable for the minichannels, frequently overestimating the boiling heat transfer coefficient. Boiling correlations for small channels are more consistent with experimental data and the predictions of Yu's correlation match the experimental results best.

Three-dimensional reconstruction of small objects has been one of the most challenging problems over the last decade. Computer graphics researchers and photography professionals have been working on improving 3D reconstruction algorithms to fit the high demands of various real life applications. In this thesis, we implemented a 3D scanner system based on fringe projection method. Two different methods have been implemented and used as the unwrapping solution in fringe projection method. A parameterization tool has been created in order to generate different fringe patterns for distinctive needs in the fringe projection method. Considering our first practical implementation (based on phase shifting and multi wavelength techniques) the number of pictures used in phase shifting method has been decreased and the effects of reducing the fringe patterns on the level of precision of the 3D model have been investigated. Optical arrangement and calibration of the system (fringe projection method) have been studied, and numerous suggestions have been proposed to improve the precision of the system. Also, an evaluation method has been implemented based on calibration techniques. The error rate on both surface and height of the 3D model compare with the object has been calculated.

In this thesis three circuits are presented that demonstrate the creation and manipulation of various phases over a large bandwidth. Many systems demand the interoperability of various circuit blocks over a large frequency range in order to minimize costs. In addition, the use of low resistivity silicon facilitates a further reduction in costs. The circuits presented in this thesis demonstrate both these key concepts by using the conventional CMOS process in addition to operating over large bandwidths which is ideal for inclusion in any number of standard wireless systems. A new novel balun is proposed that achieves wideband performance through the use of an external compensating capacitor to counter the effects of parasitic capacitances that reduce its effective bandwidth. An input stage common gate amplifier is then used to improve the return loss and provide additional gain. The fabricated active balun using the proposed circuit shows that the device performs with a 7.5 GHz bandwidth. In addition an excellent 16 dB return loss, -5.8 dBm compression point and 12 mW power consumption are also reported. Following this, an inductorless quadrature oscillator is proposed using an artificial resonator composed of conventional OTA circuits in order to increase the tuning range. The measured tuning range was found to be 100 MHz. This circuit demonstrates the ability to use a synthetic resonator circuit as a method of achieving wide tuning. The measured phase noise of -97.7 dBc/Hz is on par with other inductorless oscillators found in literature. Finally a wideband feedback quadrature generator is presented. Existing circuits do not provide a wide frequency of operation and in addition are highly susceptible to variances in component values used. The result is that the fabricated system will not operate at its intended operating frequency. In order to mitigate this problem a RC-CR network was used in conjunction with two variable gain amplifiers that uses a feedback network to actively compensate the amplitude imbalance over a large frequency range. This new design first is of its kind and the resulting circuit is measured to have over a 4 GHz bandwidth while maintaining a +/- 1 dB amplitude balance. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-03-28 16:06:33.014

Optimal generation scheduling attempts to minimise the cost of power production while satisfying the various operation constraints and physical limitations on the power system components. The thermal generation scheduling problem can be considered as a power system control problem acting over different time frames. The unit commitment phase determines the optimum pattern for starting up and shutting down the generating units over the designated scheduling period, while the economic dispatch phase is concerned with allocation of the load demand among the on-line generators. In a hydrothermal system the optimal scheduling of generation involves the allocation of generation among the hydro electric and thermal plants so as to minimise total operation costs of thermal plants while satisfying the various constraints on the hydraulic and power system network. This thesis reports on the development of genetic algorithm computation techniques for the solution of the short term generation scheduling problem for power systems having both thermal and hydro units. A comprehensive genetic algorithm modelling framework for thermal and hydrothermal scheduling problems using two genetic algorithm models, a canonical genetic algorithm and a deterministic crowding genetic algorithm, is presented. The thermal scheduling modelling framework incorporates unit minimum up and down times, demand and reserve constraints, cooling time dependent start up costs, unit ramp rates, and multiple unit operating states, while constraints such as multiple cascade hydraulic networks, river transport delays and variable head hydro plants, are accounted for in the hydraulic system modelling. These basic genetic algorithm models have been enhanced, using quasi problem decomposition, and hybridisation techniques, resulting in efficient generation scheduling algorithms. The results of the performance of the algorithms on small, medium and large scale power system problems is presented and compared with other conventional scheduling techniques.

Zugl.: Bochum, Universiẗat, Diss., 2008.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [67]-73).

Thesis (Doctoral)--Departments of Surgical Pathophysiology and Anaesthesiology, University of Lund, University Hospital MAS. / Added t.p. with thesis statement inserted. Summary in Swedish. Includes bibliographical references.