The racking performance of light-frame shear walls subjected to monotonic and cyclic loading is the focus of this thesis. The sheathing materials investigated are oriented strandboard (OSB), hardboard, fiberboard, and gypsum wallboard. The objectives of this study were to (1) obtain and compare performance characteristics of each sheathing material; (2) compare the effects of monotonic loading versus the cyclic loading response; (3) investigate the contribution of gypsum in walls with dissimilar sheathing materials on opposite sides of the wall; and (4) study the effects of using overturning anchors. The monotonic tests, which incorporated the use of hold-downs, were performed according to ASTM E564. Half of the cyclic tests were performed with hold-downs, and half were performed without hold-downs. The cyclic tests were performed according to the recently adopted cyclic testing procedure ASTM E2126. A total of forty-five walls were tested with various configurations. The size of the walls was 1.2 x 2.4m (4 x 8ft). Two tests were performed with each sheathing material subjected to each type of loading: monotonic, cyclic with hold-downs, and cyclic without hold-downs. Two tests were then performed with OSB, hardboard, or fiberboard on one side of the wall and gypsum on the other side of the wall to study the effects of using dissimilar sheathing materials on the shear walls. The OSB and hardboard exhibited similar performance, and were the strongest of the four sheathing materials. Fiberboard performed better than gypsum, but worse than OSB and hardboard. In general, the performance indicators decreased when the walls were subjected to cyclic loading. The contribution of gypsum to walls with hold-downs was significant, but was not linearly additive. The use of hold-downs had a large effect on the performance of the walls. All shear wall performance indicators decreased when hold-downs were not included, with an average reduction of 66% in the peak load. / Master of Science

abstract: This thesis aims to investigate the capacity and bit error rate (BER) performance of multi-user diversity systems with random number of users and considers its application to cognitive radio systems. Ergodic capacity, normalized capacity, outage capacity, and average bit error rate metrics are studied. It has been found that the randomization of the number of users will reduce the ergodic capacity. A stochastic ordering framework is adopted to order user distributions, for example, Laplace transform ordering. The ergodic capacity under different user distributions will follow their corresponding Laplace transform order. The scaling law of ergodic capacity with mean number of users under Poisson and negative binomial user distributions are studied for large mean number of users and these two random distributions are ordered in Laplace transform ordering sense. The ergodic capacity per user is defined and is shown to increase when the total number of users is randomized, which is the opposite to the case of unnormalized ergodic capacity metric. Outage probability under slow fading is also considered and shown to decrease when the total number of users is randomized. The bit error rate (BER) in a general multi-user diversity system has a completely monotonic derivative, which implies that, according to the Jensen's inequality, the randomization of the total number of users will decrease the average BER performance. The special case of Poisson number of users and Rayleigh fading is studied. Combining with the knowledge of regular variation, the average BER is shown to achieve tightness in the Jensen's inequality. This is followed by the extension to the negative binomial number of users, for which the BER is derived and shown to be decreasing in the number of users. A single primary user cognitive radio system with multi-user diversity at the secondary users is proposed. Comparing to the general multi-user diversity system, there exists an interference constraint between secondary and primary users, which is independent of the secondary users' transmission. The secondary user with high- est transmitted SNR which also satisfies the interference constraint is selected to communicate. The active number of secondary users is a binomial random variable. This is then followed by a derivation of the scaling law of the ergodic capacity with mean number of users and the closed form expression of average BER under this situation. The ergodic capacity under binomial user distribution is shown to outperform the Poisson case. Monte-Carlo simulations are used to supplement our analytical results and compare the performance of different user distributions. / Dissertation/Thesis / M.S. Electrical Engineering 2012

Numerous studies have shown that respirable particles contribute to adverse human health outcomes including discomfort in irritated airways, increased asthma attacks, irregular heartbeat, non-fatal heart attacks, and even death. Particle emissions from diesel vehicles are a major source of airborne particles in urban areas. In response to energy security and global climate regulations, the use of biodiesel as an alternative fuel for petrodiesel has significantly increased in recent years. Particle emissions from diesel engines are highly dependent on fuel composition and, as such, the increased use of biodiesel in diesel vehicles may potentially change the concentration, size, and composition of particles in respirable air. One indicator used to evaluate the potential health risk of these particles to humans is particle diameter (Dp). Ultrafine particles (UFPs, Dp Current research in automotive emissions primarily focuses on particle emissions measured on a total particle mass (PM) basis from heavy-duty diesel vehicles. The nation's light-duty diesel fleet is, however, increasing; and because the mass of a UFP is much less than that of larger particles, the total PM metric is not sufficient for characterization of UFP emissions. As such, this research focuses on light-duty diesel engine transient UFP emissions, measured by particle number (PN), from petrodiesel, biodiesel, and blends thereof. The research objectives were to determine: 1) the difference in UFP emissions between petrodiesel and blends of waste vegetable oil-based biodiesel (WVO), 2) the differences between UFP emissions from blends of WVO and soybean oil-based biodiesel (SOY), and 3) the feasibility of using genetic programming (GP) to select the primary engine operating parameters needed to predict UFP emissions from different blends of biodiesel. The results of this research are significant in that: 1) Total UFP number emission rates (ERs) exhibited a non-monotonic increasing trend relative to biodiesel content of the fuel for both WVO and SOY that is contrary to the majority of prior studies and suggests that certain intermediate biodiesel bends may produce lower UFP emissions than lower and higher blends, 2) The data collected corroborate reports in the literature that fuel consumption of diesel engines equipped with pump-line-nozzle fuel injection systems can increase with biodiesel content of the fuel without operational changes, 3) WVO biodiesel blends reduced the overall mean diameter of the particle distribution relative to petrodiesel more so than SOY biodiesel blends, and 4) Feature selection using genetic programming (GP) suggests that the primary model inputs needed to predict total UFP emissions are exhaust manifold temperature, intake manifold air temperature, mass air flow, and the percentage of biodiesel in the fuel; These are different than inputs typically used for emissions modeling such as engine speed, throttle position, and torque suggesting that UFP emissions modeling could be improved by using other commonly measured engine operating parameters.

Water is a simple molecule but is an essential part of life. One key aspect of the properties of water is the hydrophobic effect, and whilst there is an appreciation of this phenomenon at the macro-scale (raindrops falling off leaves) and the micro-scale (the structure of cellular systems), a complete understanding at the molecular level still eludes science. Addressing this issue, our studies involve synthetic supramolecular compounds that assemble in water via the hydrophobic effect. First of all, a novel water-soluble deep-cavity cavitand was synthesized. It possesses four endo methyl groups on top rim of the cavitand, eight water-solubilizing carboxylic acid groups coated on the cavitand exterior, and a relatively large hydrophobic interior. Compared to a previous well-studied water-soluble deep-cavity cavitand octa-acid (OA), this novel cavitand (TEMOA) possesses a non-monotonic assembly profile in the presence of a homologous series of straight-chain alkanes. Three supramolecular species were observed: 1:1, 2:2, and 2:2 and they are approximately isoenergetic. Second, we examined the guest-controlled self-sorting in assemblies. A mixture of OA and TEMOA formed hetero-capsular complex driven by the hydrophobic effect. The extent of homo- or hetero-dimerization is intimately tied to the size of the guest being encapsulated. TEMOA is less predisposed to dimerize than OA, thus TEMOA possesses the ability to form various self-assembled states, such as tetrameric and hexameric assemblies. Furthermore, we also discussed our observation of how external stimuli such as changing the nature or concentration of a co-solute salt influences a unique, unusual transition from one assembled state to another.

Neste trabalho tratamos da homotopia monotônica entre trajetórias de um sistema de controle ∑ sobre uma variedade M. Esta é uma variante apropriada da homotopia usual, na qual duas trajetórias são consideradas homotopicas se podem ser deformadas continuamente através de trajetórias. Inicialmente apresentamos alguns aspectos gerais e resultados fundamentais da teoria do controle. Em seguida, introduzimos a noção de regularidade para controles e a homotopia monotônica entre trajetórias de ∑ geradas por essa classe de controles. Em particular, apresentamos um exemplo de um sistema que admite trajetórias que são homotópicas mas não são monotonicamente homotópicas. O objetivo principal foi entender a construção (análoga), para homotopia monotônica, de espaço de recobrimento universal. Entre outros, o conjunto Γ(∑,x) de classes de homotopia monotônica das trajetórias do sistema ∑ a partir x ∈ M possui uma estrutura de variedade diferenciável de mesma dimensão que a variedade M(o espaço estado). Como consequência desse resultado temos um difeomorfismo local que nos permitirá levantar ∑ para a variedade Γ(∑,x), obtendo assim um novo sistema ∑^ em Γ(∑,x). A fim de compreendermos as propriedades universais de Γ(∑,x), tomamos um recobrimento π : N → ΑR(∑,x) no sentido de que N é uma variedade diferenciável munida com um sistema de controle ∑~ e π é um difeomorfismo local que leva e∑~ ao ∑. Comparando as trajetórias de sistemas ∑^ e ∑~ construímos uma aplicação de levantamento ƒ : Γ(∑,x) → N que relaciona ∑^ e ∑~. Finalizamos este trabalho levando em conta a classe particular de sistemas simétricos, para qual os espaços de recobrimento monotônico Γ(∑,x) e topológico M~ de M coincidem. / In this work, we deal with monotonic homotopy between trajectories of a control system ∑ on a manifold M. This is an apropriate variant of usual homotopy, where two trajectories are considered to be homotopic if they can be deformed to each other in a continuous way through trajectories. We introduce regularity for controls and consider monotonic homotopy between trajectories generated by regular controls. In particular, we present an example of a system having homotopic trajectories which are not monotonically homotopic. The main goal was to understand the construction for monotonic homotopy of the universal covering space and, in particular, the differentiable manifold structure on the set Γ(∑,x) of monotonic homotopy classes of trajectories starting at x ∈ M. As a consequence of that result, we obtain a local diffeomorphism which permits lifting of ∑ to another system ∑^ in Γ(∑,x). To consider universal properties of Γ(∑, x) we take a covering π : N → ΑR(∑,x) in the sense that N is a differentiable manifold provided with a control system ∑~ and π is a local diffeomorphism mapping ∑~ to ∑. Comparing the trajectories of ∑^ and ∑~ we construct a lifting mapping ƒ : Γ(∑,x) → N that relates ∑^ and ∑~. Finally, we take into account the particular class of symmetric systems, for which both coverings Γ(∑,x) and M~ coincide.

Em virtude da presença cada vez mais frequente de solicitações cíclicas nas estruturas de engenharia e do aprimoramento da análise de projetos, os ensaios em solos sob carregamentos cíclicos tiveram seu interesse renovado nos últimos anos. Os ensaios de laboratório são realizados de forma que simulem, da melhor maneira possível, as condições observadas em campo. Tais condições auxiliam na escolha dos ensaios a serem conduzidos para a determinação de parâmetros geotécnicos relevantes a cada situação observada em campo. Dentre os ensaios empregados na Engenharia Geotécnica, destaca-se o simple shear. Este ensaio é conhecido e utilizado para medir a resistência ao cisalhamento e a rigidez de solos. Este é o único ensaio de laboratório capaz de submeter uma amostra a condições de deformação plana sob volume constante e permitir a rotação das tensões principais. Tais condições são frequentemente representativas em diversas situações em campo como, por exemplo, o modo de cisalhamento adjacente ao fuste de uma estaca ou sob plataformas offshore com base gravitacional. Nesse contexto, um equipamento foi desenvolvido para a realização de ensaios do tipo simple shear. O aparato conta com uma câmara, na qual é aplicada pressão à amostra de solo. Diferenciando-se do equipamento comercial para tais ensaios, que emprega uma membrana com anéis metálicos, a amostra de solo neste equipamento é envolta por uma membrana de látex, o que possibilita a consolidação de forma isotrópica ou anisotrópica. Quanto ao carregamento, o equipamento desenvolvido permite que o carregamento seja realizado de forma monotônica ou clíclica. Quando do carregamento cíclico, este pode ainda ser realizado de forma a se manter a tensão controlada ou a deformação. Foram conduzidos ensaios de calibração e validação do equipamento empregando-se uma areia fina de granulometria uniforme cujas propriedades são amplamente conhecidas através de outros ensaios. Os resultados obtidos foram então comparados com estudos no mesmo material em equipamentos triaxiais, cisalhamento direto e outro simple shear. Os resultados mostraram-se satisfatórios, validando o equipamento desenvolvido. / In view of the ever more frequent presence of the cyclic solicitations on Engineering structures and the enhancement of design analysis, the soil testing under cyclic loading conditions had its interest renewed in the last years. The laboratory tests are conduced in a way that simulates, in the best way possible, the observed field conditions. Said conditions aid on the choice of the tests to be conducted in order to determinate the relevant geomechanics parameters.to each situation observed on the field. Among the employed tests in Geotechnical Engineering, it is highlighted the simple shear. This test is known and used to measure the shear strength and soil righty. This is the only laboratory test capable of submitting the sample to plane strain conditions under constant volume and allows the main stress rotations. Said conditions are frequently representative in many field situations, such as, the adjacent shear mechanism to the shaft of a pile or, under offshore platforms with gravitational base. In this context, a equipment was developed to perform simple shear tests. The apparatus has a chamber, in which it is applied confining pressure to the soil sample. Contrasting from the commercial equipment for said tests, that uses a membrane with metallic rings, in this equipment the soil sample is involved by a latex membrane, allowing the consolidation being carried out isotropically or anisotropically. The loading on this equipment can be conduced on monotonic or cyclic conditions. The cyclic loading can even be conduced by controlling the deformation or the stress. Calibration and validation testes where conduced on the equipment using a fine sand of uniform granulometry which properties are largely known through other tests. The obtained results where then compared to other tests carried out on the same material in triaxial tests, direct shear and other simple shear, The results obtained were considered satisfactory, validating the developed equipment.

Abstract not available

Insitu cementitious stabilisation is an economical, environmentally sustainable and socially advantageous means of rehabilitating pavements. With the recent availability of a wide range of binders and advanced construction equipment, the characterisation of cementitiously stabilised pavement materials has become the focus of further advancement of this technology. Australian practice has moved towards the use of Indirect Diametric Tensile (IDT) methods for the characterisation of these materials. A draft protocol for the IDT test has been prepared and specifies samples to be compacted by gyratory compactor. This procedure provides for both monotonic and repeated load testing, which aims to measure the material???s strength, modulus and fatigue life. A range of host materials, including a new crushed rock and a reclaimed existing pavement base course, were assessed when stabilised with a General Purpose cement binder as well as with a slag-lime blended binder. Materials were assess for their inherent material properties, Unconfined Compression Strength (UCS), Unconfined Compression modulus, IDT strength and modulus under both monotonic and repeated load. A number of amendments and refinements to the testing protocol were recommended. These included the use of minimum binder contents to ensure the binder was uniformly distributed and to promote heavy binding of the materials to ensure they behaved elastically. It was also recommended that samples be gyratory compacted to a pre-determined sample height to allow a constant density to be achieved. The variability of the test results was examined. UCS results were found to be comparatively as variable as other researchers had reported. IDT strength results contained a similar level of variability, which was considered to be acceptable. Modulus results, both monotonic and repeated load, were found to be five to ten times more variable than strength results, which is a generally accepted trend for modulus testing. Under repeated loading, some challenges with the test protocol were encountered. The primary challenge was obtaining reliable and repeatable diametrical displacement data for modulus calculation. This was partially overcome by the insertion of smooth spacers to prevent the Linear Voltage Displacement Transformer (LVDTs) becoming caught on the sample sides. The achievement of reliable and repeatable IDT modulus results through improved displacement measurements should be the focus of future research efforts in this area.

An ever increasing demand to exploit oil and natural gas reserves has significantly increased extraction activities even in the remotest regions of the Arctic and sub-Arctic regions of the Canadian North. Steel pipelines are the most efficient mode for transporting and distributing these resources. These pipelines, particularly buried in cold region, often subjected to extreme geo-environmental conditions, where significant inelastic deformation may occur resulting in localized wrinkles. Under continued deformation, there is a possibility of excessive cross-sectional deformation at wrinkle locations, eventually leading to fracture or damage in the pipe wall jeopardizing pipeline safety and integrity . Prior research indicated that occurrence of fracture in pipe wrinkle is rare under monotonic load-deformation process. However, a recent field fracture was observed within the wrinkle location of an energy pipeline. Similar failure mode was observed in a laboratory specimen at the University of Alberta. Both field and laboratory observations had indicated that the final failure was a “tearing” failure at the fold of the telescopic wrinkles resulting from monotonic application of axial load not aligned with pipe axis. This research program was designed to study this specific failure mode and to develop design tool for pipeline engineers. This research started with examining the failed field and test specimens. A preliminary investigation was carried out using nonlinear finite element (FE) model to simulate test and field behaviour. Numerical results have indicated that even under monotonic loading, significant strain reversals could occur at the wrinkle fold . Presence of these strain reversals was proposed as the preliminary failure criterion responsible for this unique failure mechanism. In next phase, a full-scale ‘pipe-wrinkling’ test program was carried out concurrent to this research to better understand the loading condition responsible for this type of failure. Results of this test program have shown the presence of tearing fracture or rupture in the pipe walls of several of test specimens. A series of FE analyses was then carried out to predict and verify the behaviour of these test specimens. After successful simulation of the test behaviour, further numerical analyses were carried out using tension coupon model developed herein to simulate the material behaviour using the material test data and hence to formulate the limiting conditions in terms of critical strain responsible for the tearing failure. Based on these numerical results, a double criterion  ‘Strain Reversal’ and ‘Critical Equivalent Plastic Strain Limit’, were proposed to predict tearing fracture of wrinkled pipe under monotonic loading. Results of these numerical analyses have demonstrated that the proposed criteria predict this failure mode with reasonable accuracy. In the final phase of this research, a parametric study was carried out to consider the effect of different parameters on failure modes of wrinkled pipe. Results of this parametric study describe the range of parameters under which the tearing mechanism can/may exhibit. / Structural Engineering

Modern mines require systems that quickly deliver backfill to support the rock mass surrounding underground openings. Cemented Paste Backfill (CPB) is one such backfilling method, but concerns have been raised about CPB’s liquefaction susceptibility especially when the material has just been placed, and if it is exposed to earthquakes or large mining induced seismic events. Conventional geotechnical earthquake engineering for surface structures is now relatively advanced and well accepted, and so the objective of this thesis is to consider how that framework might be extended to assess the liquefaction potential of CPB. Seismic records were analyzed for earthquakes and for large mining induced events. Important seismological trends were consistent for rockbursts and earthquakes when the signals were recorded at distances as proximate as one kilometre, suggesting that the conventional earthquake engineering approach might plausibly be adapted for such design situations. For production blasts and for more proximate locations to rockbursts, much higher frequencies dominate and therefore new design methods may be required. Monotonic triaxial tests conducted on normally consolidated uncemented mine tailings demonstrated that the material is initially contractive up to a phase transition point, beyond which dilation occurs. Most importantly the material never exhibits unstable strain softening behaviour in compression, and only temporary or limited liquefaction in extension. The addition of 3% binder results in initial sample void ratios that are even higher than their uncemented counterparts, and yet the material friction is slightly enhanced when tested at 4 hours cure. These results suggest that the flow liquefaction phenomenon commonly associate with undrained loose sand fills will not occur with paste backfill. Cyclic triaxial test results analyzed in terms of number of cycles to failure for a given cyclic stress ratio exhibited a trend consistent with previous tests on similar materials. However, the addition of 3% binder and testing at 4 hours cure resulted in an order of magnitude larger number of cycles to failure – a surprising and dramatic increase, suggesting good resistance of the material to cyclic mobility. Future research is recommended to build on these results and develop more robust methods for liquefaction assessment of CPB.