Fusion welding processes cause residual stress due to the uneven heat distribution produced by the moving welding torch. These residual stresses are characterised by a large tensile component in the welding direction. Due to the self-equilibrated nature of the residual stress, compressive ones are present in the far field next to the weld seam, which can cause different kind of distortion such as bending or buckling. Welding residual stress can be responsible of premature failure of the components, such as stress crack corrosion, buckling, and reduction of fatigue life. Localised rolling is a stress engineering technique that can be used to reduce the residual stress and distortion caused by welding. It induces plastic strain in the rolling direction, counteracting the plastic strain produced during welding. In this thesis three techniques were investigated, pre-weld rolling, post-weld rolling, and in situ rolling. These techniques have been seldom studied in the past, particularly pre-weld rolling; consequently the mechanisms are poorly understood. Finite element models allow stress and strain development during both welding and rolling processes to be better understood, providing an improved understanding of the mechanisms involved and aiding process development. A literature survey was done to find the state of the art of the computational welding mechanics simulations, stress management, and the residual stress measurement techniques, as well as the knowledge gaps such as, the thermal losses through the backing-bar in the thermal simulation, the frictional interaction in the rolling process, and the material properties of the steel used in the models. In the literature not many models that investigate the management of welding residual stress were found. After this, the general considerations and assumptions for the welding thermal mechanical models presented in this thesis were discussed. The effect of different backing-bar conditions, as well as different material properties where investigated. Both influenced the residual stress profile to varying degrees. In particular, temperature dependent heat loss to the backing-bar was necessary to capture the improved heat loss near the weld. The distortion predicted by the model was investigated to determine whether it was due to bending or buckling phenomena. Lastly, the temperature distribution and residual stress predictions were validated against thermocouple and neutron diffraction measurements conducted by Coules et al. [1–3]. Pre-weld rolling was the first of the three rolling methods considered, in which rolling is applied to the plates before performing GMA butt-welds. The principle behind this technique consisted in inducing tensile residual stress in the weld region before welding; therefore, it is similar to mechanically tensioning the weld, which can significantly reduce the residual stress and distortion. However, there was no significant change in the tensile residual stresses. On the other hand, it was possible to achieve a small reduction in the distortion, when the plates were rolled on the opposite surface to the weld; rolling in this way induced distortion in the opposite direction to the distortion induced by welding, reducing the magnitude of the latter. These results were compared with experiments conducted by Coules et al. [1,4]. A subsequent investigation combined pre-weld rolling with post-weld heating. With this additional process the residual stress and distortion were significantly reduced, and flatter residual stress profile was achieved. The post-weld rolling and in situ rolling techniques were discussed afterwards. In the post-weld rolling models, rolling was applied after the weldment was cooled to room temperature. In in situ rolling the roller was applied on top of the weld bead at some distance behind the torch, while it was still hot. The principle behind these techniques consisted in applying positive plastic strain to the weld bead region by a roller, counteracting the negative plastic strains produced in the welding process. Two roller profiles were investigated, namely, grooved, and double flat rollers. The post-weld rolling on top of the weld bead models, which used the grooved roller, showed good agreement against experimental results, producing a large reduction of the residual stress and distortion. Some discrepancies were present when the weld toes were rolled with the dual flat roller. The former roller was more efficient for reducing residual stress and distortion. The influence of different friction coefficients (between the roller and weldment, and between the backing-bar and the weldment), were investigated. It showed significant dependency on the residual stress distribution when high rolling loads were used. The frictional interaction constrained the contact area inducing more compressive stress in the core of the weld bead; therefore it produced more tensile residual stress in the surface of the weldment. Additionally, the influence of rolling parameters on the through-thickness residual stress variation was investigated. Low loads only influence the residual stress near the surface, while high loads affected the material through the entire thickness. When the dual flat roller was used to roll next to the weld bead, significant compressive residual stress was induce in the weld bead; however, the residual stress reduction was very sensitive to the contact of the roller to the weld toes; therefore, when rolling a weld bead that varies in shape along the weld, the residual stress reduction is not uniform and varies along the length. On the other hand, the in situ rolling did not produced significant residual stress or distortion reduction in all the cases analysed. The rolling occurred when the material was still hot and the residual stress was subsequently formed as the material cooled to room temperature. Numerical modelling was a very useful tool for understanding the development of stress and plastic strain during the welding and rolling processes.

The idea which has initiated this research came firstly from being a mother of an autistic child and secondly, being an experienced Applied Behaviour Analysis/Applied Verbal Behaviour “ABA/AVB” therapist working with children with autism and related disorders. It has been the researcher ambition for some time to study the effects of implementing an ABA/AVB programme on children with autism, and to report on their performance. The previous and current research has shown the importance of an early intervention in teaching children with autism. However, finding an appropriate intervention for an individual with autism is still debated among parents and professionals. Previous research has highlighted the importance of an ABA programme using the Lovaas model programme in teaching children with autism. No wider research on the AVB model has been conducted. This has led the researcher to investigate this issue further. This research has taken place at “The Autistic Centre” in Beirut. This research is the author’s attempt to study the effects and the impacts of implementing an AVB programme on children with autism. Children’s performance on specific skills will be assessed, evaluated and reported by four parties: 1. The researcher. 2. The independent psychologists. 3. The teachers. 4. The parents. The research used a combination of quantitative and some qualitative methods. The AVB Intervention used for this study was based on multiple baseline design across behaviour, participants and settings. The different use of methods for this research has contributed to the methodology, by using different methods to collect data and involving many parties who can evaluate the children’s performance and report their progress from their own perspectives. The present study demonstrated the efficiency of the AVB programme with ten children with autism. Its effects have been clear on the emergence of speech, collateral gains in social communicative behaviours and decrease of problems behaviours and the decrease of parental level stress. This research also proposed several key suggestions based on the literature review and the research undertaken. It has also contributed to knowledge of the current research regarding the implementation of an AVB Programme as an educational provision and its effects on the child and the parents.

Aim of this thesis was to shed light on the function(s) of Iba57 and Ssc1 proteins in both life cycle stages of T. brucei using RNA interference. Depletion of Ssc1 resulted in severe grow phenotype, decrease in activities of iron-sulphur cluster-containing enzyme aconitase but no increase in oxidative stress sensitivity or accumulation of ROS in mitochondrion. Down regulation of Iba57, specialized maturation factor of aconitase and homoaconitase, lead to depletion of aconitase, destabilization of Isa1 and increased sensitivity to oxidative stress and accumulation of ROS in both stages.

The topic of this thesis is the investigation of the local states of stress resulting from the introduction of av-notch in a coaxial circle on the pressurized surface of a circumferentially clamped plate subject to axisymmetric loading. The understanding of the fracture behavior of a component experiencing such a condition is of particular interest to the aerospace and defense industries where circular plate components are often utilized. In such applications, it is imperative that the designer be able to predict the loading conditions facilitating dynamic fracture. As a step towards solving such problems, the quasi-static analogy is studied. Specifically, the purpose of this research is to examine and model the precise effects a stress raiser will have on the fracture behavior and strength reduction of a circular plate machined from Ultem 1000. Parametric FEM simulations were employed to determine the correlation between notch geometry and the resulting maximum stress and stress distribution in the notch root vicinity. Stress concentration factor (SCF) relationships were developed which characterize the effect individual geometric parameters have on the notch root stresses. Mathematical models were developed to provide the elastic stress concentration factor for any combination of geometric parameters within the range studied. Additionally, the stress distributions along the notch root and ahead of the notch were characterized for a variety of geometric configurations. Test coupons were employed to not only characterize the mechanical behavior of the material, but also characterize the correlation between simple and axisymmetric loading, respectively. The development of a predictive approach for designers of such circular components to be able to accurately determine the fracture behavior of these components was the motivating factor of this study.

Yes / This paper presents an integrated model for shear friction strength of monolithic concrete interfaces derived from the upper-bound theorem of concrete plasticity. The model accounts for the effects of applied axial stresses and transverse reinforcement on the shear friction action at interfacial shear cracks. Simple equations were also developed to generalize the effectiveness factor for compression, ratio of effective tensile to compressive strengths and angle of concrete friction. The reliability of the proposed model was then verified through comparisons with previous empirical equations and 103 push-off test specimens compiled from different sources in the literature. The previous equations considerably underestimate the concrete shear transfer capacity and the underestimation is notable for the interfaces subjected to additional axial stresses. The proposed model provides superior accuracy in predicting the shear friction strength, resulting in a mean between experimental and predicted friction strengths of 0.97 and least scatter. Moreover, the proposed model has consistent trends with test results in evaluating the effect of various parameters on the shear friction strength.

Forging temperature is one of the basic considerations in forging processes. In warm forging, the metals are forged at temperatures about the recrystallization temperature and below the traditional hot forging temperature. Warm forging has many advantages when compared to hot and cold forging. Accuracy and surface finish of the parts is improved compared to hot forging while ductility is increased and forming loads are reduced when compared to cold forging. In this study, forging process of a part which is currently produced at the hot forging temperature range and which needs some improvements in accuracy, material usage and energy concepts, is analyzed. The forging process sequence design with a new preform design for the particular part is proposed in warm forging temperature range and the proposed process is simulated using Finite Element Method. In the simulations, coupled thermal mechanical analyses are performed and the dies are modeled as deformable bodies to execute die stress analysis. Experimental study is also carried out in METU-BILTIR Center Forging Research and Application Laboratory and it has been observed that numerical and experimental results are in good agreement. In the study, material wastage is reduced by proposing using of a square cross section billet instead of a circular one, energy saving and better accuracy in part dimensions is achieved by reducing the forging temperature from the hot forging to the warm forging temperature range.

Diss. Helsingin yliopisto, 2006. / Myös verkkojulkaisuna.

The aim of the the thesis is to study the development of arch effect depending on the change of the various parameters such as grid of columns, height of embankments, material of embankment fill and material of columns. The first phase of work summarizes theoretical knowledges of stone columns and arch effect. The next phase deals with analysis of the effect of arch using numerical modeling. In the next part of the second phase circular tank based on stone columns will be modeled, where deformations and stress on columns will be monitored in changing constitutive model and applying substitute characteristics. Obtained results will be evaluated in conclusion.

O álcool produzido no Brasil por meio da cana-de-açúcar é um combustível alternativo que obteve seu espaço no mercado mundial junto com o interesse dos países industrializados em contribuir para a diminuição da poluição no planeta. Para o processo de produção do álcool, há várias etapas e, uma delas é a extração do caldo da cana-de-açúcar realizada, em sua grande maioria, por equipamentos denominados \"ternos de moenda\". Conhecer o comportamento destes equipamentos sob os esforços atuantes em sua estrutura é de suma importância para a realização de novos projetos destes e uma otimização dos já existentes. Para o conhecimento de tais tensões, tecnologias na área da engenharia auxiliada por computador (CAE) trazem programas de computador (softwares) capazes de cumprir tal finalidade. Muitos destes softwares são responsáveis por uma otimização no processo de concepção de um produto, pois os mesmos são capazes de detectar falhas em projetos com extrema facilidade, coisa que seria muito difícil por cálculos realizados manualmente. Assim, o objetivo deste trabalho é estudar as tensões atuantes num castelo de moenda 53\"x90\", peça de maior expressão no conjunto do terno de moenda de mesma bitola, para auxílio em futuros projetos e otimização dos já existentes. Para o conhecimento das tensões atuantes no castelo e utilização do Cosmosworks, software de elementos finitos que apresenta resultados com grande precisão, será utilizado. Depois de analisadas, as tensões atuantes no castelo foram apresentadas com ênfase aos pontos de maior concentração de tensão. A verificação de coeficientes de segurança elevados nas mais diversas regiões do castelo também foi explorada. Com base nos resultados apresentados pôde-se otimizar o castelo de moenda reduzindo seu peso próprio em 15%, que corresponde aproximadamente a 3.000 Kg. O conhecimento das tensões atuantes em componentes para o setor sucroalcooleiro oferece condições de se projetar novos equipamentos otimizados para um mercado cada vez mais globalizado e conseqüentemente mais competitivo. / The alcohol produced in Brazil through the sugar cane is an alternative fuel that acquire her space on the world market with the interest of industrialized countries to contribute to reducing the planet pollution. In the process of ethanol production, there are several steps and one is the extraction of juice from sugar cane held, in majority, of the equipment called \"milling housing\". Knowing the behavior of this equipment efforts engaged in its structure is of paramount importance for the realization of these new projects and an optimization of existing ones. To the knowledge of these stress, technologies in the field of computer-aided engineering (CAE) bring computer programs (software) capable of fulfilling this purpose. Many software are responsible for an optimization in the process of product design, due to the fact that they are capable of detecting projects flaws with great ease, when something would be very difficult handling calculation. The objective of this work is to study the stresses working in the milling housing, the greatest expression throughout the suit of milling, to help in future projects and optimization of existing ones. To the knowledge of the stress working in the housing Cosmoworks, software for finite element that gives results with great accuracy, had been used. After the analysis, stresses working in the housing were presented with emphasis on the points of greatest stress concentration. The proof of factor of safety in the most diverse regions of the housing had been also explored. Based on the results presented, it is possible to optimize the milling housing reducing its own weight by 15% which is approximately 3,000 Kg. Knowledge of stresses in active components for the sector offers conditions to design new equipment optimized for an increasingly globalised market and thereafter more competitive.

O álcool produzido no Brasil por meio da cana-de-açúcar é um combustível alternativo que obteve seu espaço no mercado mundial junto com o interesse dos países industrializados em contribuir para a diminuição da poluição no planeta. Para o processo de produção do álcool, há várias etapas e, uma delas é a extração do caldo da cana-de-açúcar realizada, em sua grande maioria, por equipamentos denominados \"ternos de moenda\". Conhecer o comportamento destes equipamentos sob os esforços atuantes em sua estrutura é de suma importância para a realização de novos projetos destes e uma otimização dos já existentes. Para o conhecimento de tais tensões, tecnologias na área da engenharia auxiliada por computador (CAE) trazem programas de computador (softwares) capazes de cumprir tal finalidade. Muitos destes softwares são responsáveis por uma otimização no processo de concepção de um produto, pois os mesmos são capazes de detectar falhas em projetos com extrema facilidade, coisa que seria muito difícil por cálculos realizados manualmente. Assim, o objetivo deste trabalho é estudar as tensões atuantes num castelo de moenda 53\"x90\", peça de maior expressão no conjunto do terno de moenda de mesma bitola, para auxílio em futuros projetos e otimização dos já existentes. Para o conhecimento das tensões atuantes no castelo e utilização do Cosmosworks, software de elementos finitos que apresenta resultados com grande precisão, será utilizado. Depois de analisadas, as tensões atuantes no castelo foram apresentadas com ênfase aos pontos de maior concentração de tensão. A verificação de coeficientes de segurança elevados nas mais diversas regiões do castelo também foi explorada. Com base nos resultados apresentados pôde-se otimizar o castelo de moenda reduzindo seu peso próprio em 15%, que corresponde aproximadamente a 3.000 Kg. O conhecimento das tensões atuantes em componentes para o setor sucroalcooleiro oferece condições de se projetar novos equipamentos otimizados para um mercado cada vez mais globalizado e conseqüentemente mais competitivo. / The alcohol produced in Brazil through the sugar cane is an alternative fuel that acquire her space on the world market with the interest of industrialized countries to contribute to reducing the planet pollution. In the process of ethanol production, there are several steps and one is the extraction of juice from sugar cane held, in majority, of the equipment called \"milling housing\". Knowing the behavior of this equipment efforts engaged in its structure is of paramount importance for the realization of these new projects and an optimization of existing ones. To the knowledge of these stress, technologies in the field of computer-aided engineering (CAE) bring computer programs (software) capable of fulfilling this purpose. Many software are responsible for an optimization in the process of product design, due to the fact that they are capable of detecting projects flaws with great ease, when something would be very difficult handling calculation. The objective of this work is to study the stresses working in the milling housing, the greatest expression throughout the suit of milling, to help in future projects and optimization of existing ones. To the knowledge of the stress working in the housing Cosmoworks, software for finite element that gives results with great accuracy, had been used. After the analysis, stresses working in the housing were presented with emphasis on the points of greatest stress concentration. The proof of factor of safety in the most diverse regions of the housing had been also explored. Based on the results presented, it is possible to optimize the milling housing reducing its own weight by 15% which is approximately 3,000 Kg. Knowledge of stresses in active components for the sector offers conditions to design new equipment optimized for an increasingly globalised market and thereafter more competitive.