The diploma thesis deals with vehicle movement dynamics and defining a theoretical model for software simulation of vehicle passing a given trajectory, while main aim is time minimization driving mode. Simulation (algorithm for computing speed profile) is then applicated for passing experimental vehicle along Masaryk circuit in Brno. At the end, we optimize chosen vehicle parameters with derivate-free algorithms Multilevel Coordinate Search and Particle Swarm.

The thesis deals with adding new parts to program for measuring data rates in mobile communications. New program parts are used for analyzing web pages and HTTP protocol, recieving position data from GPS reciever and for creating automated measuring sequences.

Hot strip mills (HSM) are used to roll cast slabs down from their initial size to plate or sheet, which is then used to manufacture a wide variety of goods for many industrial markets. The working rolls that contact and deform the strip are arguably the primary element of the hot strip mills. The work rolls must have sufficient strength to apply the mechanical force to the strip, while still resisting the wear and thermal stresses inherent to the process. The history of the development of these work rolls spans more than a hundred years. The more recent advancement in work roll technology was the development of High Speed Steel (HSS) work rolls during the 1990's. The HSS rolls utilise a variety of carbide forming elements to improve the wear resistance. The South African Roll Company (SARCO) is an established roll producer and the only one in South Africa with a well-established international client base. SARCO is currently developing a range of high quality HSS rolls and has developed an initial HSS grade, which has shown competitive performance and durability in service compared to established HSS alloys from other roll manufacturers. Although the initial trials show great promise, significant potential for development and associated improvements are available. It has been documented that an additional annealing treatment prior to the regular heat treatment will refine the microstructure of HSS rolls, which should improve mechanical properties and performance. However, although pre-annealing has been documented, the degree of mechanical property improvement associated with the pre-annealing has not been studied and the annealing step does not appear to be commonly applied by roll producers. The first aim of this research project was to investigate the properties of the HSS material currently produced by SARCO to elucidate the source of the combination of high wear resistance and durability. The roll material identified for characterisation consisted of four sets of samples. These were subjected to intensive characterisation, which included chemical analysis, ferrite scope measurements, metallography, hardness testing, Scanning Electron Microscopy (SEM) analysis, X-Ray Diffraction (XRD) analysis and Simultaneous Thermal Analysis (STA). The good combination of performance and durability appears to be the product of the Ni additions, W:Mo ratio, high carbon content, high austenitising temperatures and balanced carbide-former additions. The second objective was to investigate the effect of annealing prior to the typical solution, "soft" quench and tempering heat treatment, on the structure and mechanical properties of the HSS material used for the outer shell of mill rolls. As-cast material was used for the analysis, which was subjected to similar intensive characterisation. High Chromium (HC) used in roll material appears to be more sensitive to both temperature and time variations in heat treatment than HSS. No grain refinement of the HSS material was achieved by the pre-annealing. Higher peak hardness and more gradual reduction in hardness beyond the peak was not found under simulated conditions, indicating that a desired increase in hardness will not be achieved in practice. It was evident that the industrial heat treatment condition cannot be sufficiently simulated by shorter time laboratory tests. The effects of pre-annealing should be researched on lower alloy bainitic HSS material if feasible and the improved wear resistance and toughness benefits of pre-annealing could be quantified by performing industrial trials and fracture toughness testing respectively. / Dissertation (MEng)--University of Pretoria, 2017. / Materials Science and Metallurgical Engineering / MEng / Unrestricted

I present new models of the elastic structure of the Pacific upper mantle that address the formation and evolution of oceanic plates. Using a surface-wave dispersion dataset, I perform anisotropic tomography to construct two-dimensional phase-velocity maps and three-dimensional velocity models of the Pacific basin. My three-dimensional elastic models describe both the radial and azimuthal anisotropy of seismic waves. In order to constrain these models, I develop regularization techniques that incorporate a priori information about the nature of the oceanic upper mantle, including both the age dependence of seismic velocities and the expected scaling relationships between azimuthal anisotropy parameters derived from realistic peridotite elastic tensors. I observe a strong cooling signal in the upper-mantle seismic velocities that is consistent with halfspace cooling of the lithospheric plate; deviations from this simple cooling signature are related to the influence of mantle plumes or other thermal alteration of the lithosphere. As plate age increases, the depth to the thermally controlled lithosphere-asthenosphere boundary increases as well. This thermal boundary, as seen in the negative gradient in seismic velocities, is consistent with the depth at which there is a transition in anisotropy fast-axis orientation. This change in anisotropy orientation is due to the transition from frozen-in lithospheric anisotropy to asthenospheric anisotropy that is related to geologically recent shear beneath the base of the plate. The anisotropy orientations and strength that we observe throughout the plate are only consistent with A-type olivine fabric. There are regions where anisotropy orientations do not align with paleospreading directions in the lithosphere or absolute-plate-motion in the asthenosphere, suggesting that small-scale convection, mantle flow, and plumes could all lead to changes in the orientation of seismic anisotropy. There is a dependence on the strength of anisotropy on spreading rate at shallow depths; this implies that corner flow at faster-spreading ridges is more effective at aligning olivine crystals in the direction of shear. I also present a new set of local surface-wave amplification maps spanning the contiguous United States. I perform a synthetic-tomography experiment in order to assess our ability to resolve variations in surface-wave amplification due to variations in local elastic structure. Local amplification derived from synthetic seismograms is very highly correlated with direct predictions of amplification, suggesting that we are able to resolve this signal well and that local amplification observations reflect elastic structure local to the station on which they are measured. Local amplification can be used as a complementary constraint to phase velocity in order to map upper-mantle elastic structure.

No description available.

Speed has long been equated with "progress". The Romans' paved roads begot much of this concept, allowing faster travel that improved communication, commerce, and enabled control over vast territories. Additionally paved surfaces whisked insect-breeding water away from homes, improving the health of those in town. Today, part-and-parcel of the definition of the developed world are tremendous amounts of solid surfaces, mostly asphalt and concrete, to move mechanized devices and water quickly. Even the shoes we wear could be seen as complementary technological devices, cushioning our feet to allow us to barrel forward more quickly along firm, manmade foundations. But the push towards this progress has had destructive consequences on our environment, including, but not limited to, our stream valleys. Often abutting intense, impervious development, the stream valley watersheds have morphed from spongy spines dense with aquatic life to de-facto storm sewers, with thick foliage merely masking severe erosion and paltry ecosystems. Quite simply, the speed at which the water is pushed down the ever-narrowed corridors as paved development encroaches, coupled with pollution from this fast runoff, renders the former fish streams dead. The recent advent of nature trails (following a mix of old hunting paths and former gristmill horse-cart ways), along unbuildable flood plains has exposed this problem in the Accotink stream valley in Northern Virginia. This thesis addresses the topic of water runoff of the Accotink stream valley and trail network. After analyzing and studying the area as a whole, the thesis focused on two scales: the larger scale of Fairfax Circle in Fairfax City in suburban Northern Virginia and a piece of this area -- a small section that acts as a threshold from urban village to natural park/trail/creek bed. This smaller section is also along the most eroded section of the Accotink Creek. At the "master plan" scale, the thesis transforms Fairfax Circle to a "village" using environmental remediation design principals to repair and regenerate this environmentally-degraded area. At the architectural scale, the thesis examines the site through the lens of the regional trail network along the stream valleys and the potential urban village at Fairfax Circle to design a trail-stop fitness center that straddles the break between conceptual urban space and repaired, stormwater-soaking stream valley. / Master of Architecture

Many research projects have been conducted to compare standing text entry with nomadic text entry. Other research projects have compared the input types of touchscreen and physical keyboards while texting. There is few literature that compares the two inputs types during a standing and nomadic text entry. This research was conducted to investigate the differences in error rate and characters per minute for both input types during both text entry conditions. To investigate these differences two devices were used, the iPhone 4 and the Blackberry Curve 9350, to type a phrase during both a standing and walking condition. Both characters per minute and error rate were analyzed. The investigation showed that there were no significant difference in error rate, but there was a significant difference in characters per minute. The touchscreen keyboard performed better in terms of characters per minutes and arguably performed better in accuracy.

Görtler vortices develop in boundary layer flows over concave surfaces due to the imbalance between centrifugal forces and the wall-normal pressure gradient. These vortices can be efficient precursors to transition in boundary layers exposed to free-stream disturbance or surface non-uniformities, because they can alter the mean flow causing the laminar flow to breakdown into turbulence. In this thesis, a control technique aimed at reducing the energy associated with Görtler vortices that develop in supersonic boundary layers is introduced and tested. The control algorithm is based on distributed blowing and suction, with sensors placed either in the flow or at the wall. The result show that there is a dependence between the efficiency of the control algorithm and the spanwise separation of the vortices, that is the energy reduction is more significant for larger spanwise separations. The efficiency of the control algorithm seems to be insensitive to the variation of the Mach number.

No description available.

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