O presente trabalho tem por objetivo desenvolver um aparato experimental para estudar, em modelo físico de escala reduzida, o comportamento mecânico de um duto enterrado submetido a variações do estado de tensões da massa de solo circundante e a um potencial movimento de massa gravitacional, com avaliação concomitante das deformações desenvolvidas no solo por meio da técnica de correlação de imagens digitais. A alteração do estado de tensão no maciço foi feita por meio da aplicação de incrementos de inclinação ao modelo. Foram realizados ensaios com o duto nas posições transversal e longitudinal no interior da caixa de ensaios, enterrado em areia pura e seca, com razão entre altura de cobertura e diâmetro do duto de 3,55. A compacidade do maciço, controlada por meio da utilização da técnica de chuva de areia, foi avaliada nas situações densa (D = 111,5 %) e fofa (Dr = 58,2%). O comportamento mecânico do duto foi avaliado por meio de instrumentação para medição da deformação específica e deflexão da parede, sendo verificado efeito de flexão lateral no duto disposto na transversal, com maiores deformações observadas na situação de maciço fofo. Para o duto disposto na longitudinal, maiores deformações específicas foram observadas para a seção instrumentada central na situação de maciço denso, contudo verificou-se a necessidade de realização de ensaios adicionais para elucidação dos resultados, em termos da interação solo/tubo ao longo do comprimento do elemento. Para a utilização da técnica de correlação de imagens digitais, as imagens foram adquiridas em um ambiente com iluminação padronizada e resolução de partícula igual a 4. A qualidade da textura da imagem foi garantida por meio da preparação de material com adição de 20% de areia colorida. O refinamento da malha de análise, avaliado por meio da alteração do tamanho dos subsets e espaçamento entre subsets, não exerceu grande influência nos campos de deslocamentos obtidos, porém maiores refinamentos permitiram extrair observações mais detalhadas do campo de deformações. A utilização da técnica permitiu ainda avaliar a evolução dos vetores de deslocamento ao longo das etapas de inclinação e a influência do duto enterrado, na posição transversal, nos deslocamentos das partículas de solo circundante. / The present work aims the development of an experimental apparatus to study the behavior of a buried pipe under different soil stress states and potential landslides in a small-scale physical model. Digital image correlation technique is also used to evaluate soil deformation. A controlled slope increment squeme were responsible for soil stress state changes. The tests were performed with the model pipe buried in pure dry sand with a buried depth ratio of 3.55. A series of four tests involving two pipe configurations inside the test box (transversal and longitudinal) and two relative density (111.5% and 58.2%) was conducted. Soil density was controlled by pluviation method. The model pipe was instrumented in order to evaluate its behavior in terms of linear strain and deflection of the pipe wall. For the transversely disposed pipe, it was observed lateral bending effect and larger strains when buried in loose sand. For the longitudinally diposed pipe, the largest strains occurred in the pipe central cross section and in the tests conducted in dense sand. Nevertheless, additional testing is needed to better clarify the results, in terms of soil/pipe interaction along the pipe length. Daily digital images were acquired under standardized conditions of illumination for the use of digital image correlation technique. The particle/pixel size ratio was set equal to 4. Image texture quality was improved by adding 20% colored sand to the material used in the investigation. The level of refinement of the analysis mesh, evaluated by varying the subset size and the spacing of subsets, did not shown significant effect in the displacement fields. However, finer meshes allowed more detailed observations in the engineering shear strain fields obtained. Additionally, the digital image correlation technique allowed the evaluation of the displacement vectors evolution along the different slope stages considered. Moreover, this technique also captured the effect of the transversely disposed pipe on surrounding soil particles displacements.

Owners of infrastructure assets have responsibility for the management of a diverse portfolio of civil engineering assets. These assets make up the foundations of modern society and are arguably pivotal in the economic growth and wellbeing of a nation. It is of no surprise therefore, that asset management business practises have risen in popularity as the UK’s infrastructure asset base continues to grow and inevitably ages with time. In the context of water and waste water infrastructure assets, which communities rely upon for health, economy and environmental sustainability, it is widely acknowledged that these assets have historically suffered from underinvestment. Whilst funding shortfalls have been evidenced historically, through the inadequacy of infrastructure to meet the needs and challenges of the past, it is of great concern that infrastructure expenditure is reducing in real terms as a result of the global financial crisis. This is leading to a widening funding gap between the available and the required finances for infrastructure investment which is further compounded by natural phenomena and human behaviours, i.e., climate change, population growth and urbanisation. To further intensify the problem, asset planning and management in the water industry is considered a complex and challenging discipline because of high interdependencies and the vast quantity of assets themselves. In acknowledgement of this global position, this thesis seeks to address some of the key challenges faced by utility companies in the adoption of asset management best practice across water and waste water assets, namely: • Operational decision making - the efficient and effective specification of least-cost rehabilitation programmes from condition information that ensure behavioural alignment with an organisations strategic objectives. • Tactical decision making - achieving risk based asset level inspection prioritisation that considers serviceability performance, for two particularly challenging asset groups: i.) High value - low volume assets and ii). Low value - high volume buried infrastructure. • Strategic decision making - identifying optimal long-term investment plans and asset management policies for assets that have previously not benefited from such technological advancements. To improve upon operational decision making, the author capitalises on the availability of condition inspection information for buried sewerage infrastructure by applying advanced optimisation techniques to help form an environment where the decision makers is presented with an array of optimal rehabilitation solutions. The trade-off curve that is presented uniquely evaluates solutions for the benefits they offer in-terms of: condition improvement, cost and operational performance. A financially favourable comparison (up to 45% saving) is drawn between the optimisation results which are automatically generated by the model and those that have been developed manually by experienced engineers in a ‘real world’ case study. However, it could be argued that the greatest benefit arises from the trade curve of feasible solutions which are presented to the decision maker across a range of investment levels. In recognition that tactical and strategic decision making have been the focus of a substantial amount of research for commonly found infrastructure assets, i.e., public sewers and water mains, a focus has been placed on improving upon and adopting best practise across infrastructure assets which have not previously benefited from the technological developments across these decision making levels. Firstly, a methodology for translating standardised condition inspection information into more meaningful reliability scores, to support risk based planning and decision making, is presented for service reservoirs. A service reservoir can be regarded as high value- low volume infrastructure asset and would typically have its condition evaluated between 1 (poor) to 5 (good). A case study demonstrates how this new reliability scoring mechanism has been successfully applied during a typical structural condition survey. The output from this process is a fully document reliability assessment for each component of the service reservoir. The output can be aggregated to provide an overall reliability assessment for the structure and/or used to target specific remedial works to troublesome components. Secondly, two methodologies are presented which address the fact that high volume – low value infrastructure assets across both the water distribution and wastewater collection networks, are typically less well understood and often sub-optimally managed in comparison to more critical or higher value assets. 1. A methodology has been developed to help UK water companies overcome the recent legislative changes associated with Section105A of the Water Act; which has transferred ownership of the private sewer network to UK water companies. The new methodology which has been developed, has allowed one of the UK’s water and sewerage companies to initiate a proactive asset management programme with the aim of addressing the deteriorating condition of these assets whilst also tackling their associated serviceability performance. Initially, a number of GIS tools are used to provide an estimate of the likely extent of the transferred network before a well-established public sewer deterioration model is used to predict the condition and operational performance of these S105A assets over time. 2. A novel deterioration modelling framework is developed by coupling the latest geospatial technologies with statistical deterioration modelling techniques. The modelling framework is specifically applied to small diameter water distribution assets (25-50mm diameter), known as communication pipes, which connect individual properties to the water distribution mains. Reliability curves are developed from failure data provided by two UK based Water Companies that have captured specific communication pipe failure records since 2001. The deterioration modelling curves and supporting data are compared and contrasted to demonstrate the robustness of this modelling approach, which is shown to be capable of modelling failure rates to a high degree of accuracy. This was validated by comparing the predicted number of failures against three years of failure data not used during the model building process. The yearly failure counts were predicted to within +/-5% accuracy and the overall cumulative modelled failure count at the end of 2014 was predicted within 1%. To conclude, the successful deterioration modelling tools for communication pipes are explored further, via the development of a strategic whole life cost optimisation framework for these assets. The outputs from the previous geospatial mapping tool are used alongside the calibrated Weibull deterioration curves to drive a whole life cost and performance analysis. Against this improved understanding of whole life costs, an optimisation algorithm is used to evaluate the trade-off between whole life costs (totex) and the prevention of future asset failures (serviceability). The model successfully identifies optimised investment policies according to the decision maker’s priorities which is evidenced in a case study that shows outperformance against existing maintenance policies for these assets. Financial savings in the region of £8.5M, or the prevention of 1,320 asset failures, were shown to be possible over a 25 years planning horizon in the case study. For the avoidance of confusion, the term ‘integrated’ is considered from the perspective of the three decision making levels associated with the management of an asset, namely: strategic, tactical and operational decision making. Therefore, data quality improvements and the management of information transactions between decisional levels are inherently considered within all of the methodologies developed in this thesis.

Carbon isotope studies are commonly used to provide a proxy for past vegetation communities and for evaluating environmental change. Original studies suggested carbon isotope ratios of soil organic matter (SOM) faithfully preserved the isotopic composition of standing vegetation with little or no modification in the pedogenic and shallow burial environment. Recent studies of modern soils and laboratory experiments suggest that this may not necessarily be the case and that degradation of SOM in the burial environment may alter the original C-isotope ratio of bulk SOM. A first step in addressing the issue is to begin to understand the transformations of SOM in the burial environment; of particular interest in this study are transformations involving microbial residues. Sedimentary sequences with stacked buried soils afford the opportunity to study the changes that may occur through time and are especially useful if numerical ages and other environmental proxies are present. The objective of this study is to thoroughly investigate the composition and quantity of organic matter that has been preserved in the surface and buried soils at the Claussen site, using Fourier Transform Infrared Spectroscopy (FTIR), which provides an estimate for the abundance of organic matter components preserved in each paleosol's SOM. We can trace the fate of bioavailable OM and determine the magnitude of preferential decay of SOM with time by first comparing the composition of bulk SOM to the composition of physically protected carbon, located in soil microaggregates (Christensen, 1992) of the stacked buried soils. The results of this project suggest differences in the composition of paleosol and surface soil SOM that could impact paleovegetation interpretations derived from δ13C values.

In the context of transistor size miniaturization the motivation of this work was focused on the fabrication process of planar double gate devices. We proposed in this work three process flows based on the use of buried mask which could allow the fabrication of self-aligned planar double gate transistors. The novel concept of buried mask consists into modifying the etch rate of a buried polysilicon or oxide layer. This etch rate modification being defined by ion implantation, etch stop or scacrificial zones aligned with the implantation mask can thus be fabricated. This technique solve the alignment of the front and back gate. Ion implantation causes damages to the implanted target, and is used to dope semiconductor material. If the implanted atoms have a small radii they can induce stress to the implanted lattice. These three consequences of ion implantation, damage, doping and stress are used to modify the etch rate of oxide and polysilicon. High etching selectivity are reached, which allow the fabrication of a localized buried sacrificial or etch stop zone, called buried mask. The definition of the buried mask being done by ion implantation, it opens the possibility to fabricate a buried mask aligned with the implantation mask. Although some more work has to be invested to fabricate planar double gate MOS using buried mask in polysilicon, this concept of buried mask, which could also be called anisotropic wet and vapor etching, is foreseen as a very promising technique in MEMS micromachining and for bio sensor applications.

This research program focused on the behaviour of low cycle fatigue (LCF) of wrinkled pipes, and was designed to develop the LCF life prediction models for the wrinkled pipes. It consisted of three phases of work, which are strip tests, full-scale pipe tests, and finite element analysis (FEA). In strip tests, 39 strip specimens were tested by a complete-reversed stroke-controlled method to investigate the effects of bend angle, bend radius, and stroke range on the low-cycle fatigue (LCF) life. Also, the LCF behaviour was explored by viewing the spectra of key variables and their corresponding hysteresis loops. The failure mechanism was discussed by examining the fracture surfaces. Two LCF life prediction models, life-based and deterioration rate-based, were developed and their prediction results were evaluated. In full-scale pipe tests, two specimens were tested according to a complicated loading procedure. The loading was a combination of axial load, bending moment, and internal pressure; and it consisted of monotonic loading stage and cyclic loading stage. Based on those two tests, the global and local behaviour were investigated, the failure mechanism was studied and the application of the developed LCF life prediction models was discussed. In FEA, three numerical models were developed and they were the strip model, the half-pipe model and the full-scale pipe model. In the strip model, the residual stresses and strains were analyzed and discussed. In the half-pipe model, the effects of pipe geometry, internal pressure, and global deformation on the wrinkle geometry were studied and discussed. In the full-scale pipe model, the full-scale pipe tests were simulated and both the global behaviour and local behaviour were discussed. From this research program, some important conclusions were obtained. The wrinkle geometry is found to be greatly related to the pipe geometry, internal pressure, and global deformation. The global deformation has become localized after the wrinkle is fully developed. The opening deformation cycle is more detrimental to wrinkled pipes than the closing deformation cycle. The test results also show that the seam weld governs the failure of wrinkled pipes if the pipes are subjected to cyclic axial deformation. The LCF life prediction models developed from this research program demonstrate good prediction capacity when they are applied to both strip tests and full-scale pipe tests. / Structural Engineering

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

1 x N optical power splitters using hybrid sol-gel glasses based on buried waveguide structure on silicon substrate were fabricated. The advantage over conventional ridge structures is the fact that Y branch of the splitters can be easily obtained with the buried structure using standard photo lithography processes. Now we can successfully make the width of Y branch of less of 1um. Proximity printing was used to define the waveguide trench on sol-gel films. Then burying the sol-gel glass into the trench to define waveguide core. Finally the waveguide was packaged for measurement after coating a sol-gel top cladding layer onto the guiding layer. The propagation losses of this waveguide device are 0.69 dB/cm and 0.70 dB/cm for TE and TM polarized lights. The coupling losses are 1.57 dB and 1.89 dB for TE and TM lights with a index contrast of 0.66 %. The insertion loss and the branching loss of the 1¡Ñ2 splitter are 5.7 dB and 0.3 dB¡Arespectively.

No description available.

No description available.

Meerkats are known to strongly rely on chemical communication in social contexts. However, little is known about their use of the sense of smell in food detection and selection. The aim of the present study was therefore to assess whether meerkats are able to (1) detect hidden food using olfactory cues, (2) distinguish the odour of real food from a single food odour component, and (3) build an association between the odour of real food and a novel odour. I employed the buried food test, widely used with rodents to assess basic olfactory abilities, designed to take advantage of the propensity of meerkats to dig. I found that the meerkats were clearly able to find all four food types tested (mouse, chicken, mealworm, banana) using olfactory cues alone and that they successfully discriminated between the odour of real food and a food odour component. In both tasks, the animals dug in the food-bearing corner of the test arena as the first one significantly more often than in the other three corners, suggesting development of an efficient foraging strategy. No significant association-building between a food odour and a novel odour was found within the 60 trials performed per animal. I conclude that meerkats are able to use olfactory cues when foraging and that their sense of smell is well-adapted for recognizing specific odours of behavioural relevance. To the best of my knowledge, this is the first study to successfully employ the buried food test with a carnivore species.