This thesis focuses on the tribological performance of tool surfaces in two steel working operations, namely wire drawing and hot rolling. In all forming operations dimensions and surface finish of the products are of utmost importance. Forming basically includes three parts – forming conditions excluded – that may be changed; work material, tool and (possibly) lubricant. In the interface between work material and tool, the conditions are very aggressive with – generally or locally – high temperatures and pressures. The surfaces will be worn in various ways and this will change the conditions in the process. Consequently, the surface finish as well as the dimensions of the formed product may change and in the end, the product will not fulfil the requirements of the customer. Therefore, research and development in regard to wear, and consequently tribology, of the forming tools is of great interest. The investigations of wire drawing dies focus on coating adhesion/cohesion, surface characteristics and material transfer onto the coated steel both in laboratory scale as well as in the wire drawing process. Results show that it in wire drawing is possible to enhance the tribological performance of drawing dies by using a lubricant together with a steel substrate coated by a polished, dual-layer coating containing both hard and friction-lowering layers. The investigations of hot rolling work rolls focus on microstructure and hardness as well as cracking- and surface characteristics in both laboratory scale and in the hot strip mill. Results show that an ideal hot work roll material should be made up of a matrix with high hardness and a large amount of complex, hard carbides evenly distributed in the microstructure. The surface failure mechanisms of work rolls are very complex involving plastic deformation, abrasive wear, adhesive wear, mechanical and thermal induced cracking, material transfer and oxidation. This knowledge may be used to develop new tools with higher wear resistance giving better performance, lower costs and lower environmental impact.

This master thesisinvestigates the possibilities to implement a digital filter for wire guidancein a truck. The analog circuits in the truck, today, are analyzed to understandtheir signal processing. The component MAX261 is especially interesting and itis analyzed in a special Section to make sure that all needed details, todevelop a digital filter, are available. When all theoretical calculation wasfinished, all the circuits were simulated to make sure that the calculationsare correct.   The digital filter is based onan analog filter which is expensive and not so easy to purchase. A requirementspecification was developed by analysis of the properties of the analog filterand how it is currently used. The analog filter is a part of a chain of analogsignal processing which mostly can be performed digitally instead.   The special type of the analogfilter makes the requirements, on the digital filter, very tough and anextensive analysis of digital filter structures was performed in order to finda suitable filter. The digital filter is of WDF (Wave Digital Filter)-type andit is very special, because it has two variable coefficients, one for thesteepness and one for the center frequency. The digital filter consists of anumber of first order filters, because a higher order filter with desiredproperties has coefficient values that are large which makes the stabilityproperties worse.   The best type ofimplementation of this filter and the signal processing are also analyzed.Finally, a prototype was developed on a development board where the maincomponent is a DSP (Digital Signal Processor). The program for the prototype iswritten in C-code and the performance of the system was verified by differenttests and measurements.

This thesis was done at DaimlerChrysler AG in Stuttgart,Germany. The aim of the thesis is to develop an algorithm for controlling a motor used in a Shift-by-Wire System. The control algorithm is to be implemented in a prototype car for further testing. The Shift-by-Wire System can be described as follows: An electrical actuator is mounted in an automatic gearbox to select gears instead of the gear stick. The actuator is controlled by a microcontroller, which runs a control algorithm. The position of the actuator is measured with a linear position sensor and sent to the controller.

Ultrasonic wire bonding is the most utilized technique in forming electrical interconnections in microelectronics. However, there is a lacking in the fundamental understanding of the process. In order for there to be improvements in the process a better understanding of the process is required. The mechanism of the bond formation in ultrasonic wire bonding is not known. Although there have been theories proposed, inconsistencies have been shown to exist in them. One of the main inconsistencies is the contribution of ultrasound to the bonding process. A series of experiments to investigate the mechanism of bond formation are performed on a semi automatic wire bonder at room temperature. 25 µm diameter Au wire is ball bonded and also 25 µm diameter Al wire is wedge-wedge bonded onto polished Cu sheets of thickness 2 mm. It is found that a modified microslip theory can describe the evolution of bonding. With increasing ultrasonic power the bond contact transitions from microslip into gross sliding. The reciprocating tangential relative motion at the bond interface results in wear of surface contaminants which leads to clean metal/metal contact and bonding. The effect of superimposed ultrasound during deformation on the residual hardness of a bonded ball is systematically studied for the first time. An innovative bonding procedure with in-situ ball deformation and hardness measurement is developed using an ESEC WB3100 automatic ball bonder. 50 µm diameter Au wire is bonded at various ultrasound levels onto Au metallized PCB substrate at room temperature. It is found that sufficient ultrasound which is applied during the deformation leads to a bonded ball which is softer than a ball with a similar amount of deformation without ultrasound. No hardening of the 100 µm diameter Au ball is observed even with the maximum ultrasonic power capable of the equipment of 900 mW. In summary, the fundamental effect of ultrasound in the wire bonding process is the reciprocating tangential displacement at the bond interface resulting in contaminant dispersal and bonding. A second effect of ultrasound is the softening of the bonded material when compared to a similarly non-ultrasound deformed ball.

Magnetic nanoscale devices have shown great promise in both research and industry. Magnetic nanostructures have potential for non-volatile data storage applications, reconfigurable logic devices, biomedical devices and many more. The S-state magnetic element is one of the promising structures for non-volatile data storage applications and reconfigurable logic devices. It is a single-layer logic element that can be integrated in magnetoresistive structures. We present a detailed micromagnetic analysis of the geometrical parameter space in which the logic operation is carried out. The influence of imperfections, such as sidewall roughness and roundness of the edge is investigated. Magnetic nanowires are highly attractive materials that has potential for applications in ultrahigh magnetic recording, logic operation devices, and micromagnetic and spintronic sensors. To utilize applications, manipulation and assembly of nanowires into ordered structures is needed. Magnetic self-alignment is a facile technique for assembling nanowires into hierarchical structures. In my thesis, I focus on synthesizing and assembling nickel nanowires. The magnetic behaviour of a single nickel nanowire with 200~nm diameter is investigated in micromagnetic simulations. Nickel nanowires with Au caps at the ends were synthesized by electrochemical deposition into nanopores in alumina templates. One-dimensional alignment, which forms chains and two-dimensional alignment, which forms T-junctions as well as cross-junctions are demonstrated. Attempts to achieve three-dimensional alignment were not successful yet. I will discuss strategies to improve the alignment process.

The original objectives of this thesis were to use the new PolarDARN radars to study the convection patterns at high latitudes and to attempt to explain them in terms of reconnection. Because the IMF is important in reconnection, studies of the Interplanetary Magnetic Field (IMF) components Bx, By and Bz were done. The study showed that <|Bz|> was lower by 21.5% than <|By|> from Jan. 2006 to Dec. 2008, so By was expected to play an important role in reconnection. The IMF, spiral angle, and the amount of warping of the solar magnetic field in interplanetary space decreased slightly during this 36-month period. The decrease in IMF was a more sensitive indicator of the solar minimum than the decrease in the 10.7 cm solar microwave flux.<p> A solar magnetic sector boundary study from the Jan 1, 2007 Dec 31, 2008 interval showed the occurrence of four or two sectors in a synodic solar rotation cycle. A sector boundary crossing frequently takes place in less than 3 hours. The transition from four sectors to two sectors is surprisingly smooth, in that no interruption in the 27-day synodic period occurs. A superposed epoch analysis of solar wind speed near sector boundary crossings showed a speed minimum about half a day before the crossing, and a maximum about two days after the crossing. The standard deviation reached a minimum at about the same time as the velocity. The sector boundary study also showed that, since Dec. 2007, there were six roughly 27-day synodic solar rotation cycles near spring equinox when away field dominated, and that the following seven 27-day cycles close to the autumnal equinox were dominated by toward field. This is consistent with the quasi-sinusoidal annual magnetic sector polarity oscillations that occur for about three years during solar minimum. These oscillations are due to the mainly dipolar magnetic field which is roughly aligned with the Suns axis, tilted 7.25° from the normal to the ecliptic plane. The three-year oscillation for the present minimum between Solar Cycles 23 and 24 appeared to begin in Dec. 2007. For the past four solar minima, an El Nino event has occurred during the last of the three oscillations, and the El Nino and sinusoidal magnetic oscillation ended together. The new solar cycle began about 6 months before that. During the past eight years, a new 3D topological null-separator formulation of magnetic reconnection and its effect on convection has been led by Dr. M. Watanabe in ISAS at the University of Saskatchewan. This formulation includes two types of interchange reconnection (Russell and Tanaka) as well as the traditional Dungey reconnection. For conditions when the IMF clock angle was within 30° of a Bz+ dominant convection, the new reconnection model shows that the convection can be driven strictly by the two types of interchange reconnection. The model predicts the existence of a reciprocal cell on closed field lines and an interchange merging cell surrounding an interior lobe cell. The construction of the PolarDARN radars at Rankin Inlet and Inuvik, completed in December, 2007, allowed polar cap convection to be measured for predominantly Bz+ conditions. The existence of the two predicted features was confirmed. This also required that satellite data be analyzed to determine the location of the open-closed-field-line-boundary (OCFLB). Several PolarDARN studies are represented to show convection for different IMF clock angles and seasons.

We study the spin polarization and conductance in infinitely long quasi one-dimensionalquantum wires under various conditions in an attempt to reproduce and to explain some of theanomalous conductance features as seen in various experiments. In order to accomplish thistask we create an idealized model of a quantum wire in a split-gate semiconductorheterostructure and we perform self-consistent Hartree-Fock calculations to determine theelectron occupation and spin polarization. Based on those results we calculate the currentthrough the wire as well as the direct and differential conductances. In the frame of theproposed model the results show a high degree of similarity to some of the experimentallyobserved conductance features, particularly the 0.25- and 0.85-plateaus. These results lead usto the conclusion that those conductance anomalies are in fact caused by the electronsspontaneously polarizing due to electron-electron interactions when an applied potentialdrives a current through the wire.

A large variety of diferrocenyl compounds bridged by an organic wire fragment in a generic form of -CH=CH-X-CH=CH- were first synthesized, in which the X unit is a functional group/atom. These compounds were studied by structural analysis, electrochemistry, intervalence NIR absorption and other spectroscopic techniques. The results indicated that metal-ligand redox matching is most essential in facilitating long-range electron transfer in the mixed-valence complexes. A series of doubly-bridged diferrocenyl compounds and wire-linked triferrocenes were also synthesized and studied. All doubly-bridged diferrocenyl compounds demonstrated nearly doubled electronic coupling in comparison to their singly-bridged analogues. Thus the use of parallel wires in such systems represents a facile approach to improve communication in molecular electronics. For triferrocenes linked by symmetric wires, the electronic interaction between the redox-active centers was rather dynamic when the bridging component was short or the charge was delocalized among the ligand and metal centers. For triferrocenes bridged by asymmetric wires, depending on the direction of the polar linking chain, the central ferrocene becomes a molecular switch, turning on or off the communication between the two end ferrocenes. Finally, to eliminate the metal-ligand orbital mixing problem, we also bound the wires with two redox-active styrylpyrrole termini, for which the molecules are purely organic. It was found that when the ð-conjugation was maintained, the oligomers were fully delocalized systems.

The goal of this thesis is to design the steering vehicle system by joystick. The main function of the steering vehicle system is drivers can operate the joystick with electrical control to accomplish steering motion. In this paper , the main design framework of the steering vehicle system is divided into three stages of the experiment, vehicle architecture, vehicle dynamic simulation and vehicle test results . The overall system is modified Go-kart as a platform, develop a suitable joystick framework in the vehicle, and apply the encoder on the joystick, which transfer the control information into the position signal, to be the input command of steering motor control program. According to the steering by wire for brushless DC servo motor control strategy, the system control architecture achieve the goal by embedded-DSP. And to test double-lane change by Go-kart. Experimental results recorded by gyroscope can compare the steering situation of joystick with steering wheel.

There are two coupled primary objectives for this study of buoyancy-driven turbulence. The first objective is to create a new diagnostic for collection of measurements to capture the physics of Rayleigh-Taylor (RT) mixing. The second objective is to use the new diagnostic to specifically elucidate the physics of large Atwood number, ( )( )2 1 2 1 / ρ ρ ρ ρ + − = t A , RT mixing. Both of these objectives have been satisfied through the development of a new hot-wire diagnostic to study buoyancy-driven turbulence in a statistically steady gas channel of helium and air ( 6 . 0 03 . 0 ≤ ≤ t A ). The capability of the diagnostic to simultaneously and instantaneously measure turbulent velocity and density fluctuations allows for a unique investigation into the dynamics of Rayleigh-Taylor mixing layers at large At, through measurements of turbulence and mixing statistics. The new hot-wire diagnostic uses temperature as a fluid marker for helium and air, which is possible due to the Lewis number ~ 1 (Le = ratio of thermal diffusivity to mass diffusivity) for helium and air, and the new diagnostic has been validated in an At = 0.03 mixing layer. The energy density spectrum of v′ ′ ρ , measured experimentally for the first time in RT mixing, is found to closely follow the energy distribution of v′ , up to the Reynolds numbers investigated ( ( ) mix t h gA h υ 6 2 Re 2 / 3 = ~ 1450). Large At experiments, with At = 0.6, have also been achieved for the first time in a miscible RT mixing layer. An asymmetric penetration of the bubbles (rising fluid) and spikes (falling fluid) has been observed, resulting in measured self similar growth parameters αb = 0.060 and αs = 0.088 for the bubbles and spikes, respectively. The first experimental measurements of turbulent velocity and density fluctuations for the large At case, show a strong similarity to lower At behaviors when normalized. However conditional statistics, which separate the bubble (light fluid) and spike (heavy fluid) dynamics, has highlighted differences in v′ ′ ρ and rms v′ in the bubbles and spikes. Larger values of v′ ′ ρ and rms v′ were found in the downward falling spikes, which is consistent with the larger growth rates and momentum of the spikes compared to the bubbles. These conditional statistics are a first in RT driven turbulence.