Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-07-23T10:56:10Z No. of bitstreams: 0 / Made available in DSpace on 2015-07-23T10:56:10Z (GMT). No. of bitstreams: 0 / Para a certificação de um procedimento de soldagem, quer seja de alta responsabilidade na soldagem de oleodutos e gasodutos em tubulações de aço carbono ou para um uso rotineiro e diário em fábricas e oficinas, deve ser realizada uma análise profunda dos fenômenos ocorridos no material de base (MB), no metal de adição (MA) e na zona afetada pelo calor (ZAC). Por meio desta análise criteriosa na qualificação de um procedimento de soldagem, o procedimento é liberado para ser utilizado, seja qual for o objetivo final da soldagem. Apenas com a Especificação do Procedimento de Soldagem (EPS) qualificada em mãos é possível iniciar os trabalhos de soldagem, e caso esta seja seguida integralmente, o sucesso do processo está a um passo de se concretizar. Para demonstração desta interação existente entre qualificação, análise dos resultados, aprovação dos ensaios e aprovação da especificação, foi desenvolvido este trabalho utilizando o material de base na forma tubular API 5L Gr. B soldado com os processos eletrodo revestido (SMAW) e arame tubular autoprotegido (FCAW-S). Foi utilizada uma junta tubular como exemplo de estudo e qualificação de um procedimento de soldagem baseado na documentação contida na norma da Petrobrás N-2301 e em outros códigos e normas, que regem a qualificação do processo de soldagem utilizado em refinarias e plantas de produção brasileiras. Foram estudados em conjunto os resultados obtidos por meio de ensaios mecânicos, ensaios não destrutivos e microestruturais. Ambas as Especificações dos Procedimentos de Soldagem preliminares (pEPS), estabelecidas antes do início da soldagem dos dois processos de soldagem, foram aprovadas e qualificadas, satisfazendo as características macro e microscópicas, metalúrgicas e mecânicas da junta soldada. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Diplomová práca je zameraná na napäťovú a deformačnú analýzu elektricky vyhrievaného potrubia a príslušných častí. Cieľ práce je analýza častí potrubia samostatne a vo vzájomnom pôsobení voči medzným stavom, a zistenie maximálneho dovoleného zaťaženia. Potrubie je analyzované voči medznému stavu pružnosti a maximálnej dovolenej deformácií. Podpora je analyzovaná s cieľom nájsť adekvátne zaťaženia a silové reakcie počas inštalačnej fázy. Nakoniec je vyšetrované vzájomné pôsobenie. Potenciálne prekročenie daného medzného stavu je diskutované v adekvátnej kapitole.

M.A. / Literature indicates that childhood ADHD has received considerable attention and recognition in today’s society and is effectively represented in the DSM. In comparison, there is still much controversy surrounding ADHD in adults (aADHD), despite the fact that almost 50 to 70% of people diagnosed with childhood ADHD continue to manifest symptoms in adulthood. Research indicates that aADHD manifests differently to childhood ADHD, in that the core symptom is inattention and not hyperactivity. Research also indicates that there is a high comorbidity between aADHD and substance dependence, including nicotine dependence. It is hypothesized that these individuals present with hypodopamine, and nicotine acts on a number of neurotransmitter pathways, including the dopaminergic and acetylcholinergic pathways, effectively stimulating the release of dopamine. Whilst there is considerable literature on nicotine and ADHD, there is a complete lack of literature on the relationship between aADHD and Hookah Pipe smoking. This study aimed to rectify this situation. The present study was conducted with two major purposes in mind: (1) to investigate the relationship between Hookah Pipe smoking and its effects on attention and concentration in young adults with Attention Deficit/Hyperactivity Disorder (ADHD) symptomatology, and (2) to demonstrate whether Hookah has a greater effect than cigarettes (as Hookah reportedly has higher concentrations of nicotine than cigarettes). A total sample of 39 participants (14 males, 35 females) aged 18 to 26 years was recruited and divided into the following six groups using the ASRS, the Burke-Austin Self-Report ADHD Questionnaire and a substance abuse questionnaire as screening tools: ADHD (Hookah), ADHD (Nicotine), ADHD (Non-Smoking), Non-ADHD (Hookah), Non-ADHD (Nicotine) and Non-ADHD (Non-Smoking). Furthermore, a quasi-experimental research design was used, whereby the Cambridge Neuropsychological Test Automated Battery (CANTAB) ADHD Battery was administered across three test conditions, with a seven minute intervention between the pre- and post-intervention, and a 90 minute waiting period between the immediate and intermediate post-intervention, so as to test the effects of the nicotine as it neared its elimination half-life of two hours.

Flood propagation over urban areas can cause an interaction between the free-surface flow and large underground pipe networks used for storm drainage and sewage, causing outflows and inflows at the bed. The associated waves may collide with each other and the surface waves. In this thesis the shallow water equations are used to model this type of wave interaction over dry or wet beds with bathymetry gradients and friction terms. The proposed shallow water scheme is solved based on finite volume high-resolution Godunov-type methods. The solver is well-balanced and can accurately balance the source terms and flux-gradients for the steady-state solutions. The solver also utilises a new type of Riemann wave speed to provide depth-positive results over nearly dry beds and dry states. Additionally a new type of source term is introduced in the continuity equation to model pipe inflow and outflow conditions at bed connections. For the standard one-dimensional shallow water equations the numerical results are validated with analytical solutions or other reference solutions provided in the literature. This includes the incipient Riemann problems for nearly dry and dry-states, steady flow over a hump in a rectangular channel and the wave propagation problem. Eventually, the generation of dry bed in the middle, over discontinuous topography is considered. Close agreement is achieved between the shallow water scheme and analytical or reference solutions for the above test cases. For the shallow water problems with influx/efflux source terms comparisons are made with STAR-CD, a commercial Navier-Stokes solver for general fluid flow prediction. The shallow water model is first used to simulate vertical flows through finite gaps in the bed. Next, the interaction of the vertical flows with a dam-break flow is considered for both dry and wet beds. An efflux number, En, is defined based on the vertical efflux velocity and the gap length. A parameter study is undertaken to investigate the effect of the one-dimensional approximation of the present model, for a range of non-dimensional efflux numbers. It is found that the shallow flow model gives sensible predictions at all times provided En<0.5, and for long durations for En>0.5. Dam break flow over an underground connecting pipe is also considered for the one-dimensional efflux problems. To solve two-dimensional problems the shallow water scheme uses the dimensional-splitting method which solves each one-dimensional Riemann problem in the x- and y-directions separately. The cross-derivative terms for second-order accuracy are incorporated by solving another Riemann problem in the orthogonal direction. For two-dimensional problems first the dam-break problems are considered over wet and dry beds. Then, flood propagation over complex terrain is demonstrated. Next, efflux discharge is modelled in isolation over a dry bed and then with dam-break interaction, comparing with STAR-CD results. Again very good agreement is shown between the two-dimensional shallow water model and STAR-CD for the efflux numbers of En<0.5. For modelling the inundation problem over an underground pipe network the solver is coupled with the general underground pipe network solver to calculate the efflux discharge as the flood waves pass through the pipe network. For analysing the pipe network with unknown effluxes an additional set of equations is incorporated into the solution of a general pipe network solver. The shallow water solver coupled to an underground pipe network is then used to simulate dam-break interaction with pipe networks with 9 and 25 nodes to demonstrate the versatility of the method.

The main focus of this work is to investigate experimentally the transition to turbulence of a yield stress shear thinning fluid in Hagen-Poiseuille flow. By combining direct high speed imaging of the flow structures with Laser Doppler Velocimetry (LDV), we provide a systematic description of the different flow regimes from laminar to fully turbulent. Each flow regime is characterized by measurements of the radial velocity, velocity fluctuations, and turbulence intensity profiles. In addition we estimate the autocorrelation, the probability distribution, and the structure functions in an attempt to further characterize transition. For all cases tested, our results indicate that transition occurs only when the Reynolds stresses of the flow equals or exceeds the yield stress of the fluid, i.e. the plug is broken before transition commences. Once in transition and when turbulent, the behavior of the yield stress fluid is somewhat similar to a (simpler) shear thinning fluid. We have also observed the shape of slugs during transition and find that their leading edges to be highly elongated and located off the central axis of the pipe, for the non-Newtonian fluids examined. Finally we present a new phenomenological approach for quantifying laminar-turbulent transition in pipe flow. This criterion is based on averaging a local Reynolds number to give ReG. Our localised parameter shows strong radial variations that are maximal at approximately the radial positions where puffs first appear during the first stages of turbulent transition. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

This thesis is concerned with the performance and measurement uncertainty of wire-mesh sensors in different air-water flow regimes in horizontal pipes. It also presents measurements of void fraction and interfacial velocity in such flows. It was found that the interfacial velocity measurements of the wire-mesh sensors were in good agreement with those taken with a high-speed camera and estimates of the uncertainties of these measurements are presented. Drift-flux models were fitted to the measurements and it was found that the parameters of these models were not only sensitive to the flow regime, but also to the liquid superficial velocity.

D.Ing. / This study is a numerical investigation into the behaviour of cracks in uPVC pipes under pressure. This study is a continuation of a Masters dissertation which showed that leakage exponents vary significantly from the theoretical orifice exponent of 0.5 for cracks in pipes for different materials. This study looks at the behaviour of cracks in more detail and specifically with regard to the parameters of the pipe and crack. Using Finite Element Analysis the relationship between the pressure head and the leak area in pipes with longitudinal, spiral and circumferential cracks was investigated. It was found that the longitudinal, spiral and circumferential crack areas increase linearly with pressure. The slope of this linear relationship depends on various parameters, including loading state, pipe dimensions and pipe material properties. The effect that the individual pipe parameters had on the pressure-area slope was investigated. These parameters included the material properties of the pipe (Young’s modulus, Poisson’s ratio and longitudinal stress), the geometry of the pipe (internal diameter and wall thickness) as well as the geometry of the crack (length of the crack and the width of the crack). Once the effect of the pressure-area slope m is known, the link between the conventional leakage exponent N1 and the pressure-area slope m was further investigated and the effect of each parameter on the leakage exponent N1 was found. Using various data techniques the above data was combined and processed to find mathematical relationships that give reasonable descriptions of the pressure-area slopes of longitudinal, spiral and circumferential cracks. Once these equations for the pressure-area slopes were determined it was possible to obtain three new relationships for leakage from longitudinal, spiral and circumferential cracks.

The most common way to transport oil and natural gas in Canada is by using pipes. In the last years, population growth has led to an increase in the pipeline network. This increase will generate new areas of research such as the detection of leakages or cracks and the maintenance of the pipeline system as a whole. In this thesis, a novel hypermobile robot, capable of moving along pipes of different diameters, is proposed and developed. The robot is composed of three modules, two propulsive modules and one control module linked by passive joints. The propulsive module has eight actuators: four gearmotors to propel the robot along the pipe, and four servomotors to control the radial position of the robot in the pipe and to maintain the robot's balance. A Raspberry Pi is used to control the actuators, acquire sensor feedback, and receive commands from a remote wireless user-controlled GUI. An existing dynamic controller is adapted to the robot's architecture. Simulations and experimental tests in open-loop and closed-loop modes are performed to evaluate the effectiveness of the robot's design and controller. The results show the efficiency of the mechanical and electronic components of the robot since it is capable of following the generated paths. The outcome of this thesis can be used in trajectory tracking controllers and for in-pipe robot design.

This thesis studies the lifetime of the PE pipes materials. For determination of the lifetime one of the standard accelerated tests (Full Notch Creep test) was used. The main goal is to assess the influence of different types of detergents on lifetime. Specimen preparation and measurement procedure corresponding to the relevant ISO standard (ISO 16770: Plastics - Determination of environmental stress cracking (ESC) of Polyethylene (PE) - Full Notch Creep Test (FNCT)). Air, distilled water, Arkopal N 090 and Arkopal N 110 were used as detergents.

Předmětem této diplomové práce je návrh robotické buňky pro tvarování hydraulických trubek. Práce obsahuje analýzu technologie tvarování trubek a zdůvodnění potřeby automatizace celého procesu. Z návrhů jednotlivých konstrukčních uzlů byly vybrány nejvhodnější řešení a ty pak byly aplikovány při konstrukci buňky. Robotická buňka byla navržena s ohledem na bezpečnost provozu, funkčnost a jednoduchou ovladatelnost. Na závěr je vypracováno ekonomické zhodnocení projektu. K práci je přiložen návod pro ovládání, výkresová dokumentace, model buňky a výsledky simulace.