<p>In vehicles with electric transmission and independent wheel stations, it is possible to have a possibility to control propulsion, steering and suspension individually for each wheel. This makes it possible to improve mobility, performance and driving safety. The long term goal of this work is to develop a methodt hat can evaluate and improve the mobility of such vehicles in terrain. This contribution concerns how a six wheeled electric transmission vehicle should be modelled to enable evaluation of the dynamic behaviour in different type of terrain. This is made by combining modelling of vehicle, transmission and tire-terrain behaviour. </p><p>For wheeled vehicles an electric transmission with hub motors provides the ability to accurately control the torque on every wheel independently, giving a great ability to improve both mobility in terrain and vehicle behaviour on road. In this work the components of a diesel-electric powertrain for off-road vehicles are modelled and a control layout with the possibility to include functions for improved performance both while driving off- and on-road is proposed.</p><p> To handle driving on soft ground, a tire/terrain model is needed. The model should include lateral deformation in order to be able to steer. A tire/terrain model is derived based on the ideas of Wong and Reece. The terrain characteristics are chosen to be described by parameters according to the Bekker model, since this data are widely available in literature.</p><p> The developed tire/terrain model has been implemented together with a vehicle model. This terrain vehicle model is shown to be able to estimate sinkage, rolling resistance, traction force and steering characteristics, of a six wheeledterrain vehicle using electric transmission. </p><p>To conclude, models of a six-wheeled vehicle with electric transmission and tire models both for soft and rigid ground have been developed. These models form a simulation platform, which makes it possible to evaluate control strategies for the electric transmission with the purpose to improve mobility.</p>

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This thesis deals with the development of experimental techniques for the study of complex flows inspired to a large extent by the papermaking process. In particular one part of this thesis is devoted to the development of laboratory experiments based on index-of-refraction matching and imaging techniques to study the behavior of dilute and concentrated suspension of elongated particles. Another part is aimed at exploring the potential of the synergy between experiments and numerical simulations to access quantities otherwise not-measurable in complex flows. Highspeedimaging experiments have been specifically designed for this purpose. The first of the Refractive IndexMatching (RIM) experiment was aimed at studying the flow generated during the filtration of a fiber suspension using Particle Image Velocimetry (PIV) and pressure drop measurements. The experiments were performed in a vertical laboratory filtration device. Index of refraction matching of fibers and fluids allowed measurements to be performed in the proximity and, to some extent, in the forming network during filtration. The area over which the forming network induces velocity gradients has been measured and have been found to be independent of the Reynolds number but dependent on the fiber length and the structure of the network. Analysis of the flow scales in the proximity of the network showed that the signature of the mesh used to filter the suspension is never completely suppressed as the network thickness increases. Also, pressure drop measurements over a static fiber network have been performed. A linear dependence of the pressure drop with the basis weight (mass of fibers in the network per unit area) and a non-dimensional filtration resistance independent of filtration velocity and network thickness (if network compressibility is accounted for) was found. These findings can help explain characteristics that are observed on paper sheets and help improvede watering efficiency. The second RIM experiment was aimed at measuring the interactions of Taylorscale elongated particles with turbulence. RIM particles with embedded tracers and Stereoscopic PIV were combined to simultaneously measure fluid phase and particle velocity. The novelty of this technique is that it allows to measure the three-dimensional angular velocity vector of arbitrarily shaped particles. This technique was applied to study the interaction of neutrally buoyant ellipsoidal particles with stationary homogeneous isotropic turbulence. The results were compared to the case of spherical particles. The main result is that both spherical and ellipsoidal particles provide enhancement of the small scales and reduction of the large scales at volume concentrations as low as 0.1%. However, the reduction of the large scales was much more evident for spherical particles. These results highlight the fact that particle elongation introduces different mechanisms of turbulent modulation as compared to the spherical particles. The first of the high-speed imaging experiments was to provide a database for test and validation of a CFD-based flow observer for complex flows. For this purpose time resolved measurements of a turbulent confined jet have been performed with high-speed PIV. The measurements have been used both as a feedback signal and as a reference for the evaluation of a CFD-based estimator for complex flows. Furthermore, based on the measurements Kalman filters have been designed and implemented in the observer. The experimental data have also been used to compare two modal decompositions, namely Proper Orthogonal Decomposition and Dynamical Modal Decomposition and evaluate their ability to describe the global behavior of complex flow. The second of the high-speed imaging experiment was applied to study spreading of a droplet on a solid surface. These experiments have been performed with extremely high time-resolution (140000 fps), over a range of parameters (in terms of droplet viscosity, equilibrium contact angle and droplet size) larger than any other experiment reported in the literature in a single work. By combining the experiments and direct numerical simulations a dissipative mechanisms arising from the contact line movement has been identified and the corresponding macroscopic coefficient has been measured.i / QC 20110519

<p>A mathematical framework has been developed for describing the effects of inherent and induced anistropy in clays. The structure of governing equations permits, in general, the modelling of the sensitivity of soil response to the rotation of principal stress axes. The framework employs a continuum measure of material fabric, which is defines as an implicit function of the spatial distribution of porosity/void ratio. The set of classical functions describing the state of the material is thus enriched by new tensorial functions reflecting the orientation of the fabric. Such a formulation is advantageous over a conventional plasticity approach. It remains physically descriptive, in a sense that, the material response is a function of the specific manifestations of the microstructure. The presented approach is general and its applicability extends to other geological materials, provided the proposed evolution law (Chapter 2) is appropriately modified and the material functions are adequately selected. In its present form, the formulation does not account for irreversibility of both the plastic flow and the evolution of microstructure during histories experiencing stress reversals. However, the mathematical structure of the constitutive relations, as formulated in Chapter 3, is such that those effects can quite easily be incorporated into the proposed framework. A key to full reliability of the proposed concept is a proper verification of the evolution law. The identification of the oriented fabric is not a simple matter and requires the use of complex experimental techniques. Some suggestions in that respect have been made in Chapter 2, where a general procedure for the estimation of the components of the porosity tensor from experimental observations has been proposed.</p> / Thesis / Doctor of Philosophy (PhD)

This work has two parts. The first part of the work (in Chapters II, III, IV and V) presents a method for locating the point of impact using acoustic emission techniques.The second part of the work is modeling the ultrasonic fields generated by one and two spherical cavities placed in front of a point focused acoustic lens using the semi-analytical distributed point source method (DPSM).Acoustic emission (AE) refers to the generation of transient elastic waves during the rapid release of energy from localized sources within a material.In this work the acoustic emission has been used for locating the point of impact on anisotropic and homogeneous or non-homogenous flat plates and cylindrical structures. In these cases the wave speed is a function of the angle of propagation. An optimization function is introduced and minimized to get the location of the impact point.This method has been used on a flat (fiber reinforced polymer) plate. The proposed new objective function reduces the amount of time needed for solving the problem and improves the accuracy of prediction. The method is extended to cylindrical structures for which the objective function is written in cylindrical coordinates and the method is tested on a FRP shell.In Chapter IV an alternative method is introduced called the near-field acoustic emission (AE) beamforming method. It has been used to estimate the source locations by using a small array of sensors closely placed in a local region. To validate the effectiveness of the AE beamforming method a series of experiments on a FRP shell are conducted. The experimental results demonstrate that the proposed method can correctly predict the point of impact.The semi-analytical mesh-free technique DPSM is then used to model the ultrasonic field in front of a point focused acoustic lens; anomalies such as cavities are introduced in the medium in front of the acoustic lens and the effect of those cavities are studied. Solution of this problem is necessary to get an idea about when two cavities placed in close proximity can be distinguished by an acoustic lens and when it is not possible.

<p>AbstractThis thesis discuss how United Parcel Service (UPS) develop its aircraft maintenanceprogram after import of McDonnell Douglas MD-11aircraft and the process of exporting newMD-11 aircraft from manufacturer in USA to European operator as passenger aircraft. It alsodiscusses the process of importing the same types of aircraft as freight carrier. The aircraftundergo, through different modifications at Singapore Technologies Aerospace (STA)conversion from passenger to freight carrier, a program specially designed for UPS airlinesbefore import to USA.The thesis work was carried out in close communication with the maintenance department atUPS in California and Kentucky, McDonnell Douglas manufacturing plant in Missouri and atBoeing in Washington.The aim of this thesis was to examine and discuss the rules and regulation of import andexports of aircraft in U.S. based on UPS import of MD-11 aircraft. Furthermore, to discussthe transformation of maintenance program from one airline to another, with emphasis onhow U.S. operator develop their maintenance program.McDonnell Douglas manufactures MD-11 aircraft, and as aircraft manufacturing companythey must comply with the United States of America Federal aviation regulation part 21requirements. Besides that, the company has bilateral agreement with the buying countrySwitzerland, facilitating the reciprocal airworthiness certification of civil aeronauticalproducts exported between the two parties. Bilateral airworthiness agreement or aviationsafety agreement with implementation procedure for airworthiness facilitate the airworthinesstechnical cooperation between the Federal Aviation Administration (FAA) and its counterpartSwitzerland Civil Aviation Authorities (SCAA).UPS buy MD-11 aircraft after being modified as freight carriers. In order to obtainairworthiness certification from FAA UPS and Boeing secures that the aircraft is airworthyand have got appropriate overall maintenance service through a careful investigation processof the technical history and background of the aircraft. After receiving the FAA certificateUPS in cooperation with Boeing develop the maintenance program, before the aircraft isassigned for service in the UPS fleet.During my work it has been difficult to find information about the technical history of theaircraft, mainly because the first operator Swissair became bankrupt and all documentationwas transferred to Boeing and then to UPS. There were also many companies involved in theprocess of converting passenger aircraft to freight carrier, like ST Aero Subsidiary, Sasco inSingapore and Boeing.The work can be used as a reference to check what part of FAA deals and documents areneeded for import and export of aircraft, and what should be done to start the import andexport process. It guides the reader to an immediate understanding of regulatory organizationand their particular departments or part numbers.</p>

<p>The aim of this project is to calculate how much energy could be saved in the School of Jädraås, in the municipality of Ockelbo. The objects of study were the lighting and the ventilation systems, not only because of the energy saving but due to the comfort also. After our study, the municipality wants to use our results to improve all their municipality buildings and save as much energy as it is possible in the whole municipality.</p><p>We analyzed the hours when the ventilation system is working during the whole year, and we calculated how much energy could be saved if the amount of working hours were decreased or if new devices, as heat exchangers, were installed.</p><p>In the lighting system part, the aim was not only the energy saving, but the comfort also. The currently lighting system is quite bad, specially in the dinning room, where bulbs are still lighting the room. These bulbs, anyways, should not be changed in the next ten years. The lighting system in the learning rooms is also old. Although there are fluorescent lamps already, some new lamps with lower energy consumption and better efficiency can be installed.</p>

The aim of this project is to calculate how much energy could be saved in the School of Jädraås, in the municipality of Ockelbo. The objects of study were the lighting and the ventilation systems, not only because of the energy saving but due to the comfort also. After our study, the municipality wants to use our results to improve all their municipality buildings and save as much energy as it is possible in the whole municipality. We analyzed the hours when the ventilation system is working during the whole year, and we calculated how much energy could be saved if the amount of working hours were decreased or if new devices, as heat exchangers, were installed. In the lighting system part, the aim was not only the energy saving, but the comfort also. The currently lighting system is quite bad, specially in the dinning room, where bulbs are still lighting the room. These bulbs, anyways, should not be changed in the next ten years. The lighting system in the learning rooms is also old. Although there are fluorescent lamps already, some new lamps with lower energy consumption and better efficiency can be installed.