Research on bainite and martensite structures has indicated that lower bainite needles have a refining effect on the lath martensitic structure. Lower bainte needles partitions prior austenite grains and will consequently have a refining effect on the subsequent formed lath martensite. Smaller austenite grains will result in smaller lath martensitic packets and blocks and will result in enhanced mechanical properties.   In order to create a variation of lower bainte structure in a matrix of martensite, two different heat treating methods were tested. The work was focused towards the formation of lower bainite during isothermal heat treating in molten salt, above and below the MS-temperature. Both un-tempered and tempered samples were analyzed .Two different materials were tested, both were AISI 4140 but with a slightly difference in hardenability. The material provided by Ovako Steel is 326C and 326F the later had a higher hardenability. In order to better distinguish the two structures from each other when studied under a microscope, a variation of etching methods were tested.  It was possible to create a variation of lower bainite structures in a matrix of martensite.  326F shows less amount of lower bainite and provides a higher average surface hardness before tempering.

The capacity of soft annealing of low alloyed tubes at Ovako’s continuous annealing furnaces have been evaluated by comparing how it is done today with information from published and internal articles on the subject. It was found that it is possible to reduce the cycle time by 30 % for one furnace, 55 % for one furnace and 72 % for two furnaces. Two separate fullscale tests were made to assess whether the faster soft annealing procedure was feasible. The tests were performed without any reconstruction of the furnace and were made by continuously vary the speed of the batch inside thefurnace. The temperature in the batch was measured and compared with results from computer simulations of the heating/cooling sequences. The computer simulations were performed in COMSOL. The soft annealing was evaluated according to the SEP-520 standard ,which means evaluating the microstructure and hardness. The results show that the faster heat treatment could yield lower grades than today but still meet it’s requirements. In order to achieve this increase  a reconstruction of the furnaces is needed and the reconstruction is  briefly treated in the report. Ideas to further increase the speed of the soft annealing procedure are also presented.

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The presented dissertation focuses on non-covalent interactions of hyaluronan of different molecular weights (9–1540 kDa) with basic (oligo)-amino acids (especially arginine) and the antimicrobial peptide cecropin B. High-resolution ultrasonic spectroscopy (HR-US), isothermal titration calorimetry (ITC) and potentiometric titration techniques were chosen to investigate the interactions. The thesis focuses on the characterization of interactions, especially with respect to the used molecular weight of interacting polymers and the ionic strength of the environment. Whether interactions occur or not was determined primarily by the length of the arginine oligomer chain. For monomeric amino acids, the interactions were investigated mainly by potentiometric titrations. Interactions were observable from arginine oligomers with eight monomer units. The molecular weight of hyaluronan mainly affected the intensity of the interactions. The transition between the individual conformations of hyaluronan (rod and random coil) was especially significant. Investigation of interactions was performed in water, in solutions with different concentrations of sodium chloride and in PBS. The sufficiently high ionic strength of the solution was able to suppress the interactions in water between the oligomers of arginine and hyaluronan. The basic antimicrobial peptide cecropin B has been shown to interact with hyaluronan in water but not in PBS. Based on these results, it was possible to conclude that the hyaluronan-cecropin B system would be particularly suitable for topical applications.

The work described in this dissertation focuses on developing simple yet effective assays integrating nucleic acid (NA) aptamers with rolling circle amplification (RCA) for the detection of non-NA biomarkers. The first project, a comprehensive literature review, highlights the current state of the art in functional NA-based RCA applications, and identifies shortcomings in the detection of non-NA targets with RCA. Biosensor design is critically evaluated from four key perspectives: regulation, efficiency, and detection of RCA, and the integration of all three components for point of care (POC) applications. The second project investigates how target-binding to a linear aptamer can be utilized to regulate RCA in a simple and inexpensive format. Phi29 DNA polymerase (DP) exhibits difficulty processing DNA strands that are bound to non-NA materials such as proteins. The work uses this restriction of phi29 DP as a feature by utilizing protein-binding aptamers as primer strands (aptaprimers) for RCA. The simplicity is showcased by adapting the method to a cellulose paper-based device for the real-time detection and quantification of PDGF or thrombin within minutes. As the second project is a turn-off sensor, the third project exploits the inherent 3’-exonuclease activity of phi29 DP to generate a simple turn-on assay instead. As target-bound aptamers were shown to be resistant to exonuclease activity, the phi29 DP preferentially digests target-free aptaprimers instead of target-bound aptaprimers. The target-bound aptaprimer could be liberated by a circular template (CT) by incorporating toehold-mediated strand displacement (TMSD), and used for RCA. Sensitivity was improved relative to project two, though the dynamic range was narrow owing to difficulty liberating target-bound aptaprimer at high target concentrations. Project four instead used RecJ, which has 5’-exonuclease activity, to modulate aptaprimer availability. Similarly to project three, target-binding conferred protection on the aptaprimer from 5’-exonuclease digestion by RecJ. By including a free 3’ terminus on the aptaprimer, inhibition of RCA due to target binding was avoided and CT-mediated TMSD was not needed, simplifying the assay. As well, this approach was generalizable as it was demonstrated using both a protein (thrombin) and a small molecule (ochratoxin A) target. This turn-on method further improved the assay compared to project three with a 100-fold enhancement in sensitivity and a restoration of the dynamic range. In sum, this work contributed multiple simple and sensitive approaches for the real-time fluorescent detection of proteins and small molecules with the RCA of linear aptamers. / Thesis / Doctor of Science (PhD)

Fischer-Tropsch synthesis (FTS), developed in the early 1900's, is defined as the catalytic conversion of H2 and CO to hydrocarbons and oxygenates with the production of H2O and CO2. Accurate microkinetic modeling can in principle provide insights into catalyst design and the role of promoters. This work focused on gaining an understanding of the chemistry of the kinetically relevant steps in FTS on Fe catalyst and developing a microkinetic model that describes FTS reaction kinetics. Stable Al2O3-supported/promoted (20% Fe, 1% K, 1% Pt) and unsupported Fe (99% Fe, 1% Al2O3) catalysts were prepared and characterized. Transient experiments including temperature programmed desorption (TPD), temperature programmed hydrogenation (TPH), and isothermal hydrogenation (ITH) provided insights into the chemistry and energetics of the early elementary reactions in FTS on Fe catalyst. Microkinetic models of CO TPD, ITH, and FTS were developed for Fe catalyst by combining transition state theory and UBI-QEP formalism. These models support the conclusion that hydrocarbon formation occurs on Fe via a dual mechanism involving surface carbide and formyl intermediates; nevertheless, hydrocarbon formation is more favorable via the carbide mechanism. Carbon hydrogenation was found to be the rate determining step in the carbide mechanism. CO heat of adsorption on polycrystalline Fe at zero coverage was estimated to be -91.6 kJ/mol and -64.8 kJ/mol from ITH and FTS models respectively, while a mean value of -50.0 kJ/mol was estimated from the TPD model. Statistically designed steady-state kinetic experiments at conditions similar to industrial operating conditions were used to obtain rate data. The rate data were used to develop a microkinetic model of FTS. FTS and ITH appear to follow similar reaction pathways, although the energetics are slightly different. In both cases, hydrocarbon formation via the carbide mechanism was more favorable than via a formyl intermediate while carbon hydrogenation was the rate determining step. Promotion of Fe with K does not alter Fischer-Tropsch synthesis reaction pathways but it does alter the energetics for the steps leading to the formation of CO2. This phenomenon accounts for the CO2 selectivity of 0.3 observed for K-promoted Fe against 0.17 observed for un-promoted Fe. A Langmuir Hinshelwood rate expression derived from the microkinetic model was put into a fixed bed FTS reactor design code; calculated reactor sizes, throughput, temperature profiles and conversion are similar to those of pilot and demonstration FTS reactors with similar feed rates and compositions.

[pt] Testes de formação são normalmente realizados para determinar as propriedades rochosas do reservatório e os dados obtidos costumam ser interpretados com base no pressuposto que o reservatório é homogêneo na direção vertical e descrito por um modelo uni dimensional. No entanto, muitos reservatórios são compostos por diversas camadas que possuem características diferentes. Os poços de produção nesses reservatórios podem receber óleo de mais de uma camada. Em um sistema de reservatório estratificado, o comportamento da pressão e da temperatura não é necessariamente o mesmo de um sistema em camada única e raramente revela as mesmas propriedades médias de todo o sistema. Prever as características das camadas individuais é importante para descrever adequadamente o reservatório e melhorar o gerenciamento da produção. Este trabalho apresenta um modelo numérico, transiente-térmico para um sistema acoplado poço - reservatório 2D, levando-se em consideração efeitos Joule-Thompson responsáveis pelo aquecimento / resfriamento do fluido, expansão/compressão adiabática, além de efeitos de condução e convecção para o poço e o reservatório em um escoamento monofásico. A análise bidimensional do reservatório permite que se simule zonas de estratificação e barreiras. O modelo permite fluxo através de camadas adjascentes com propriedades de rocha diferentes. Pressão e temperatura a uma certa posição no poço produtor são avaliadas ao longo do tempo. Resultados mostram que a análise do transiente de pressão (PTA) e a análise do transiente de temperatura (TTA) podem ser utilizadas para caracterizar diferentes configurações de um reservatório estratificado. / [en] Well formation tests are usually performed to determine rock properties of a reservoir and the obtained data has often been interpreted based on an assumption that the reservoir is homogeneous in the vertical direction and described by a 1-D model. However, many reservoirs are found to be composed of different number of layers that have different characteristics. Production wells in such reservoirs may receive oil from more than one layer. In stratified reservoir system, the pressure and temperature behavior are not necessarily the same as in single layered system, and rarely reveals the same average properties of the entire system. The prediction of the characteristics of the individual layers is important to describe properly the reservoir and improve production management. This work presents a numerical transient-thermal model for a coupled wellbore/2D-reservoir considering Joule-Thompson heating/cooling, adiabatic fluid expansion/compression, conduction and convection effects for both wellbore and reservoir for a single-phase fluid flow. The two-dimensional reservoir model allows the analysis of stratified zones and barriers. The model allows cross flow between the adjacent layers with different rock properties.Wellbore temperature and pressure at a certain gauge depth are evaluated along the time. Results show how pressure transient analysis (PTA) and temperature transient analysis (TTA) can be used to characterize different configuration of stratified reservoirs.

[pt] A caracterização de reservatórios é uma ferramenta importante para a gestão da produção do mesmo. Testes de poços são comumente usados para caracterizar reservatórios, pois são as únicas fontes de dados dinâmicos durante a etapa de exploração. Esses testes medem as respostas de pressão e temperatura nos poços, dadas condições controladas de produção, injeção ou estática. Geralmente, apenas os dados de pressão são pós-processados para caracterizar o reservatório. Entretanto considerar apenas os dados de pressão podem levar a interpretações errôneas devido ao negligenciamento dos efeitos térmicos, causando erros na estimativa de propriedades do reservatório e, consequentemente, um gerenciamento ineficiente do mesmo. Além disso, os dados de pressão possuem diversas fontes de ruído que podem comprometer a precisão dos resultados dos testes. Trabalhos recentes mostram que o uso de dados de temperatura podem melhorar a estimativa de parâmetros do reservatório. Neste trabalho, o método ensemble smoother with multiple data assimilation (ES-MDA) foi aplicado em casos sintéticos criados por um simulador não-isotérmico de fluxo no reservatório-poço que considera o aquecimento de Joule-Thomson e efeitos de resfriamento, expansão / compressão de fluido adiabático, condução e convecção na equação de balanço de energia. Os dados sintéticos medidos foram obtidos adicionandose ruídos gaussianos e harmônicos aos sinais calculados para simular ruídos nas medições e efeitos de maré, respectivamente. Foi realizada uma análise de sensibilidade da matriz CD do método ES-MDA utilizada na atualização dos parâmetros a serem estimados. Os resultados mostram que o acoplamento dos dados de temperatura aos dados de pressão no ajuste de histórico promoveu uma melhora nas estimativas dos parâmetros do reservatório, principalmente para a região de dano e a porosidade do reservatório. Para as análises, nas quais os dados de pressão tiveram a inclusão de ruído harmônico, a adição de dados de temperatura também se mostrou de grande importância para a caracterização precisa do reservatório. / [en] Reservoir characterization is an important tool for production/reservoir management. Well tests are commonly used in reservoir characterization and are the only source of dynamic data during the exploration period. These tests typically measure the pressure, rate and temperature responses at a well during controlled production, injection, or static conditions. Generally, only pressure data is post-processed in reservoir characterization. However, considering only pressure data can lead to misinterpretation associated with the neglected thermal effects, causing errors in reservoir properties estimation and consequently inefficient reservoir management. Besides that, pressure data have several noise sources that may compromise the accuracy of test results. Recent results have shown that temperature data can be used to improve reservoir parameter estimation. In this work, the ensemble smoother with multiple data assimilation method (ES-MDA) was applied in synthetic cases created by an in-house non-isothermal reservoir-well flow simulator that considers the Joule-Thomson heating and cooling, adiabatic fluid expansion/compression, conduction, and convection effects in the thermal energy balance equation. The synthetic measured data was obtained by adding gaussian and harmonics noises to the numerical predictions to simulate equipment and tidal effects, respectively. A sensitivity analysis of the effect of the CD matrix used for updating parameters of the ES-MDA method on the parameters estimations was carried out. The results show that adding temperature data to the observed data in the history matching improves the estimates of the reservoir parameters, especially for the skin region and reservoir porosity. For the analyses in which the pressure data had the addition of harmonic noise, the inclusion of temperature data also proved to be of great importance for an accurate characterization of the reservoir.

One hundred billion tons of mine solid waste are estimated to be produced worldwide each year. In Canada, the mining and oil industries produce the most solid and semi-solid waste in the country, with more than a billion tons each year. In the earlier days of mining, the initial practices that were used to contain these waste materials consisted of surface storage, river dumping or just simple abandonment, while the more recent practices include dam impoundment and underground waste fill. These methods however can potentially cause environmental hazards and geotechnical problems. Against this context and as a result of stricter environmental regulations, cemented paste backfilling has been developed as a solution. This relatively new technology uses the produced waste tailings to backfill the mine stopes, greatly reducing their environmental impact while offering proper structural support in an efficient manner. However, the cost of cemented paste backfill (CPB) is greatly impacted by the binder content which can constitute up to 75% of its total cost. Additionally, the binder is usually mostly composed of ordinary Portland cement, and its production is highly energy-intensive and generates a large volume of carbon dioxide (CO₂). Indeed, it is estimated that the cement industry accounts for approximately 7% of the global anthropogenic CO₂ emissions, which is expected to increase on an annual basis. All of these factors have compelled the mining industry to seek alternatives for cement to enhance CPB strength, in hopes of reducing its carbon footprint. Against this context, this study investigates the effect of the addition of nanoparticles, namely nano silica (SiO₂) and nano-calcium carbonate (CaCO₃), on the strength development of CPB cured at a constant room temperature and in non-isothermal conditions. Nanoparticles have been studied and used as chemical admixtures in different cementitious materials with promising results; non-isothermal curing conditions better reflect the in-situ thermal curing conditions of CPB. Thus, numerous different laboratory tests and analyses, including uniaxial compressive strength (UCS), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests, thermogravimetric/derivative thermogravimetric (TG/DTG) analyses and electrical conductivity monitoring, have been conducted on CPB samples with or without nanoparticles, and cured at room temperatures or under non-isothermal conditions. The non-isothermal conditions replicate the development of temperature in two different sizes of CPB structures in the field. The results show that CPB that contains nanoparticles show a higher UCS over the entire period of curing in all of the tested conditions. The mechanical performance is further enhanced when tested under higher temperatures in non-isothermal temperature profiles. Most of the strength increase takes place at the early ages (3 days) of the testing. The reason for the improvement in the mechanical strength is linked to accelerated binder hydration and the nucleating and filler effects of the nano-material, which is corroborated by results obtained through microstructural analyses and EC monitoring. The use of natural gold tailings affects the mechanical performance of CPB and the accelerating effect of the nanoparticles due to sulphate attacks. Overall, these promising findings can help to contribute to reducing the carbon footprint of mining activities, and improve the efficiency and cost-effectiveness of mine backfilling processes.

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