Thesis (doctoral)--Université de Genève, 1938. / Includes bibliographical references (p. [103]-107) and index.

Permanent magnet machines have become an attractive topology for several applications due to their high power density and brushless qualities as compared to conventional wound field machines or squirrel cage machines. The presences of permanent magnets provide distinct advantages, but at the same time unique behaviors that must be accounted for. Recent work has developed permanent magnet machines for high-power and high-speed applications such as may be found in the petro-chemical industry, naval ships, and energy storage systems. / text

Conventional PM machines have fixed PM excitation and can only perform flux-weakening by controlling the d-axis current. This current incurs the power dissipation and reduces the efficiency during flux-weakening operations. Memory machines change this situation by introducing the memory function, namely magnetizing or reversely magnetizing Al-Ni-Co PMs to change the air-gap flux density. This provides another new way to realizing flux-weakening. And the elimination of the flux-weakening d-axis current improves the overall efficiency. But the single-memory machines have lower power density due to the low-energy Al-Ni-Co PMs. By incorporating the memory concept and with the intention of improving the power density, the DC-excited PMBL dual-memory machines have been proposed and implemented, based on two kinds of PMs which are high-coercivity Nd-Fe-B PMs and low-coercivity Al-Ni-Co PMs. The Nd-Fe-B PMs provide a strong magnetic field to excite high air-gap flux density; while the Al-Ni-Co PMs can be forward magnetized to strengthen the magnetic field produced by Nd-Fe-B PMs or can be reversely magnetized to cancel that field. Consequently the air-gap flux density can be controlled within a wide range. A series of design principles on such kind of dual-memory machine are devised for guidance. The key design principles involve how to determine the number of salient poles on the stator and rotor, how to choose the surface areas and thicknesses of the two kind of PM pieces and how to size the rotor dimension. Generally, increase on the proportion of Nd-Fe-B PMs will raise the base field and the load capacity. On the other hand, increment on the proportion of Al-Ni-Co PMs will extend the controllable flux range. Analysis is also carried out on the equivalent magnetic circuit to formulate the magnetizing force exerted on Al-Ni-Co PMs. The machine model is analyzed by using time-stepping FEM (TS-FEM) and co-simulation of FEM software and Matlab Simulink. The dynamic reverse magnetizing processes are simulated and presented in details under different magnetizing current. In addition the effect of adding iron bridges between the two kinds PMs is also evaluated by simulations. Furthermore, the control methods are evaluate by simulations and experiments. The direct torque control (DTC) scheme is adapted to this doubly-salient dual-memory machine and a torque estimator is proposed to facilitate the DTC method. Both of the simulation results and the experimental results confirm the validity of the proposed design principles and the effectiveness of the control methods. Eventually, this dual-memory machine is proposed as a pole-changing wind power generator and a pole-changing EV machine. Simulation and experimental results have verified the validity of the pole-changing scheme and the pole-protection scheme. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Im Rahmen der Untersuchungen wurden an 60 auf Implantatabutments zementierten Einzelzahnkronengerüsten aus Zirkoniumdioxid Abzugsversuche durchgeführt, um die zur Dezementierung der Kronengerüste nötigen Kräfte zu ermitteln. Als variable Parameter dienten hierbei drei unterschiedliche Abutmentgeometrien, sowie unterschiedliche Zementsysteme. Mittels des beschriebenen CAD/CAM- Verfahrens wurden die Kronengerüste aus Zirkoniumdioxid hergestellt. Die Zugversuche wurden mit der Universalprüfmaschine Zwick Z007 (Zwick, Ulm) durchgeführt und mittels „TestXpert“ (Software Zwick, Ulm) ausgewertet. Die nötige Kraft, welche zu einem vollständigen Abriss der Zirkoniumdioxidgerüste von dem Implantatabutment führt, wurde in Newton gemessen. In den Ergebnissen zeigt sich eine signifikante Wechselwirkung zwischen den beiden Faktoren Abutmentgeometrie und Zement (p<0.002). Während sich bei dem konfektionierten Abutment kaum ein Unterschied zwischen den Zementarten zeigt (p=0.2495, 95%KI [-26.93,7.45]), sind bei dem individuell niedrigen Abutment für den Zement Telio CS höhere Abzugskräfte nötig (p<0.0001, 95%KI [56.15, 98.01]). Dieser Effekt kehrt sich beim hohen Abutment um (p=0.0008, 95%KI [- 66.26,-20.62]). Es ist hier folglich kein einheitlicher Einfluss des Faktors Zement zu beobachten. Ein möglicher Einfluss auf die Retentionskraft, bzw. das Retentionsverhalten von zementierten Zirkoniumdioxid-Suprakonstruktionen auf Implantatabutments bedingt durch verschiedene Abutmentgeometrien wäre denkbar. Als Schlussfolgerung für die Praxis bestätigten sich die gezeigten Vorteile in der Anwendung von modernen semi-permanenten Kompositzementen für die Befestigung CAD/CAM gefertigter vollkeramischer Restaurationen auf Titanabutments, wobei die Indikation bei individuellen Abutmentgeometrien jeweils kritisch zu stellen ist.

This thesis presents a detailed comparison of the torque-speed characteristics of three permanent magnet synchronous machine designs based on how the magnets are mounted. The machines investigated are an interior permanent magnet machine, an interior-rotor surface-mounted machine and an exterior-rotor surface-mounted machine. They are designed for traction drives in hybrid electric vehicles. Two sets of comparisons based on the same machine volume and starting torque are performed. Important issues, such as machine mass and cost, cogging torque, and flux-weakening capability are addressed. Computer simulations were performed to estimate their performances and the results are presented. Design guidelines and tradeoffs of their performances are extracted from the simulation results. Relative strengths and limitations of different PM machine types are highlighted.

Purpose: To describe patient & tumor characteristics among rectal cancer patients in Nova Scotia, to determine factors associated with permanent colostomy and oncologic outcomes and to determine the relationship between surgeon knowledge and oncologic outcomes.Methods:The Provincial cancer registry identified new rectal cancer patients from in Nova Scotia. A comprehensive review of inpatient, outpatient and cancer center medical records was used to assemble the cohort. Surgeon knowledge was assessed using a survey with questions pertaining to rectal cancer care.Results: Patient & tumor characteristics were similar between hospitals providing rectal cancer care. Patients treated by high volume cancer center surgeons are less likely to undergo a permanent colostomy or have a local recurrence compared to patients treated elsewhere. Patients treated by surgeons with a high survey score have improved clinical and oncologic outcomes.Conclusions: There is an opportunity to improve rectal cancer care in Nova Scotia.

The object of this research is to assess the effects of Ontario’s new immigration policy on young non-permanent residents. In particular, it is to evaluate how the wage gap between young non-permanent residents and young Canadian citizens has changed in the labor market of Ontario from 2001 to 2006 to demonstrate influences of new policy. On November 21, 2005, the governments of Ontario and Canada signed the first Canada-Ontario immigration agreement that relaxed several requirements for temporary workers to apply for permanent residency. This paper selected data from the 2001 and 2006 population census to conduct a linear regression to analyze the wage gap and the effects of immigration policy. By using the difference-in-difference approach, this paper found that there was no significant positive effect of the new policy on the entry earnings of non-permanent residents in Ontario.

If A is an nxn matrix, then the permanent of A is the sum of all products of entries on each of n! diagonals of A. Also, A is called doubly stochastic if it has non-negative entries and the row and column sums are all equal to one. A conjecture on the minimum of the permanent on the set of doubly stochastic matrices was stated by van der Waerden in 1926 and became one of the most studied conjectures for permanents. It was open for more than 50 years until, in 1981, Egorychev and Falikman independently settled it. Another conjecture (which, if it were true, would imply the van der Waerden conjecture) was originally stated by Holens in 1964 in his M.Sc. thesis at the University of Manitoba. Three years later, Dokovic independently introduced an equivalent conjecture. This conjecture is now known as the Holens-Dokovic conjecture, and while known not to be true in general, it still remains unresolved for some specific cases. This thesis is devoted to the study of these and other conjectures on permanents.

Structural Health Monitoring (SHM) is a means of identifying damage from the structural response to environmental loads. Real-time SHM offers rapid assessment of structural safety by owners and civil defense authorities enabling more optimal response to major events. This research presents an real-time, convex, integral-based SHM methods for seismic events that use only acceleration measurements and infrequently measured displacements, and a non-linear baseline model including hysteretic dynamics and permanent deformation. The method thus identifies time-varying pre-yield and post-yield stiffness, elastic and plastic components of displacement and final residual displacement. For a linear baseline model it identifies only timevarying stiffness. Thus, the algorithm identifies all key measures of structural damage affecting the immediate safety or use of the structure, and the long-term cost of repair and retrofit. The algorithm is tested with simulated and measured El Centro earthquake response data from a four storey non-linear steel frame structure and simulated data from a two storey non-linear hybrid rocking structure. The steel frame and rocking structures exhibit contrasting dynamic response and are thus used to highlight the impact of baseline model selection in SHM. In simulation, the algorithm identifies stiffness to within 3.5% with 90% confidence, and permanent displacement to within 7.5% with 90% confidence. Using measured data for the frame structure, the algorithm identifies final residual deformation to within 1.5% and identifies realistic stiffness values in comparison to values predicted from pushover analysis. For the rocking structure, the algorithm accurately identifies the different regimes of motion and linear stiffness comparable to estimates from previous research. Overall, the method is seen to be accurate, effective and realtime capable, with the non-linear baseline model more accurately identifying damage in both of the disparate structures examined.