No / The Leeds die drawing process has been used to produce biaxially oriented polypropylene pipes with significant enhancement of hoop mechanical properties in terms of tensile modulus and tensile strength owing to a unique orientation of the ¿ crystallites throughout their cross-section. Pendulum impact tests on these pipes show major improvements in impact resistance. Hydrostatic pressure tests were undertaken at room temperature 95 and 110°C. Major improvements in behaviour were found including more than an order of magnitude increase in lifetime at 95°C. Furthermore, the toughness was improved enormously leading to a brittle tough transition temperature below ¿70°C.

Stormwater pipe infrastructure collects and conveys surface runoff resulting from rainfall or snowmelt to nearby streams. Traditionally, stormwater pipe systems were integrated with wastewater infrastructure through a combined sewer system. Many of these systems are being separated due to the impact of environmental laws and regulations; and the same factors have led to the creation of stormwater utilities. However, in the current ASCE Infrastructure Report Card, stormwater infrastructure is considered a sub-category of wastewater infrastructure. Stormwater infrastructure has always lacked attention compared to water and wastewater infrastructure. However, this notion has begun to shift, as aging stormwater pipes coupled with changes in climatic patterns and urban landscapes makes stormwater infrastructure more complex to manage. These changes and lack of needed maintenance has resulted in increased rates of deterioration and capacity. Stormwater utility managers have limited resources and funds to manage their pipe system. To effectively make decisions on allocating limited resources and funds, a utility should be able to understand and assess the performance of its pipe system. There is no standard rating system or comprehensive list of performance parameters for stormwater pipe infrastructure. Previous research has identified performance parameters affecting stormwater pipes and developed a performance index using a weighted factor method. However, the weighted performance index model does not capture interdependencies between performance parameters. This research developed a comprehensive list of parameters affecting stormwater pipe performance. This research also developed a performance index using fuzzy inference method to capture interdependencies among parameters. The performance index was evaluated and validated with the pipe ratings provided by one stormwater utility to document its effectiveness in real world conditions. / Master of Science

Orientador: Raimundo Leite Cruz / Banca: Antônio de Pádua Sousa / Banca: Edmar José Scaloppi / Banca: Alexandre Barcelos Dalri / Banca: Jarbas Honório de Miranda / Resumo: Com o desenvolvimento da tecnologia dos plásticos, tornou-se possível à construção de tubos emissores, com padrão de qualidade, a custos relativamente baixos. O emprego da irrigação localizada, pelo sistema de gotejamento, ganhou no Brasil novo impulso a partir dos anos 90, com a instalação de diversas empresas internacionais especializadas neste mercado. As empresas mais importantes do mundo se fazem presente no Brasil e algumas multinacionais estão produzindo aqui parte de sua linha de produção, como: Netafim, Plastro, Amanco, NaanDan e como empresa brasileira fabricante, existe a Petroisa. Esse trabalho teve por objetivo caracterizar e avaliar de forma técnica e hidráulica alguns tubos emissores para gotejamento, comercializados no mercado brasileiro de acordo com as normas ISO 8796:2004 e ISO 9261:2004. O experimento foi conduzido no Laboratório de Irrigação do Departamento de Engenharia Rural, da Faculdade de Ciências Agronômicas, Universidade Estadual Paulista "Julio de Mesquita Filho" - Campus de Botucatu, São Paulo. A norma ISO 9261:2004 prescreve critérios para avaliar e especificar gotejadores com vazão inferior a 24 L h-1 e tem por característica principal, a flexibilidade para adaptar economicamente qualquer laboratório de irrigação, porque não especifica as características da bancada de ensaios. 2 Os ensaios visaram à determinação dos seguintes parâmetros: Coeficiente de variação de fabricação, equação característica da relação entre pressão e vazão, espessura da parede, diâmetro interno, espaçamento entre emissores, resistência à pressão hidráulica à temperatura ambiente e à temperatura de 40oC, resistência à tensão de 160 N e 180 N, e ensaio de envelhecimento precoce. As análises mostraram um coeficiente de variação de fabricação (CVf) inferior a 0,07 para todos os tubos emissores... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: With the domain of the technology of plastics, it became possible to manufacture quality emitting pipes standard, at relatively low costs. Trickle irrigation method, using emitting pipes, gained in impulse Brazil during last decade 90, with the installation of several specialized international industries. Multinationals industries such as Netafim, Plastro, Amanco, NaanDan and a Brazilian manufacturer, Petroisa are producing here part of its line of production. This work had the objective, to characterize and evaluate emitting pipes, commercialized in Brazil according to ISO 8796 and ISO 9261:2004 standards. The 4 tests were conducted in the Laboratory of Irrigation of the Faculdade de Ciências Agronômicas - Campus of Botucatu, São Paulo, Brazil. The following parameters were evaluated: manufacturing variation, pressure and discharge equation, thickness of the wall, internal diameter, emitters spacing, resistance to the hydraulic pressure at the current temperature and at raised temperature (40oC), resistance to the 160 tension and 180 N, and precocious aging. The analyses had shown manufacturing coefficients of variation below 0,07 for all the emitting pipes, (maximum value allowed by ISO 9261:2004) standard. The exponents of pressure (x), in the pressure discharge e friction were of 0.431, 0.502, 0.450, 0.575, 0.533, 0.480, 0.470 for Petro Drip, Golden Drip, Chapin, Queen Gil, Aqua Traxx, Tiran and Amanco Drip, emitters respectively, classifying them as not compensating. For ISO 9261:2004, the value of x should not exceed 0.2 to be classified as compensating. The evaluated emitters (Ram, Naan PC, Amanco Drip PC and Twin Plus) had values lesser than 0,075. The test of resistance to the tension, as ISO 9261:2004 is a useful tool to classify an emitting in reusable and not reusable pipe. Aqua Traxx emitter was classified as not reusable. It presented probably... (Complete abstract, click electronic address below). / Doutor

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

No description available.

No description available.

The Loop Heat Pipe (LHP) is a passive, two-phase heat transfer device used, most commonly, for thermal management of aerospace and aeronautical electronic equipment. A unique feature is a porous wick which generates the necessary capillary action required to maintain circulation between the heat source and the heat exchanger. What differentiates LHP devices from traditional heat pipes, which also work through the use of a wick structure, is the constrained locality of the wick, placed solely in the evaporator, which leaves the remainder of the piping throughout the device as hollow. This provides the LHP with a number of advantages, such as the ability to transport heat over long distances, operate in adverse gravitational positions and to tolerate numerous bends in the transport lines. It is also self-priming due to the use of a compensation chamber which passively provides the wick with constant liquid access. These advantages make LHPs popular in aerospace and aeronautical applications, but there is growing interest in their deployment for terrestrial thermal management systems. This research had two aims. Firstly, to create and validate a robust mathematical model of the steady-state operation of an LHP for terrestrial high heat flux electronics. Secondly, to construct an experimental LHP, including a sintered porous wick, which could be used to validate the model and demonstrate the aforementioned heat exchange and gravity resistant characteristics. The porous wick was sintered with properties of 60% porosity, 6.77x10-13 m2 permeability and an average pore radius of 1μm. Ammonia was the chosen working fluid and the LHP functioned as expected during horizontal testing, albeit at higher temperatures than anticipated. For safety reasons the experimental LHP could not be operated past 18 bar, which translated into a maximum saturated vapour temperature of 45°C. The heat load range extended to 60 W, 50 W and 110 W for horizontal, gravity-adverse and gravity-assisted operation respectively. Because of certain simplifying assumptions in the model, the experimental results deviated somewhat from predicted values at low heat loads. Model accuracy improved as the heat load increased. The experimental LHP behaved as expected for 5° and 10° gravity-assisted and gravity-adverse conditions, as well as for transport line variation, in which performance was assessed while the total tubing length was increased from 2.5 m to 4 m. Overall, the construction of the LHP, particularly of the porous wick, its operation and the modeling of the constant conductance mode of operation proved to be successful. The variable conductance mode of operation was not accurately modeled, nor was expected behaviour in the elevation testing encountered, although the reasons for these results are suggested. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2013.

Orientador: Eugênio José Zoqui / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T10:27:34Z (GMT). No. of bitstreams: 1 Cicero_RenatodeSouza_M.pdf: 4231594 bytes, checksum: f0889ace44452237f6ef4aac57f6652d (MD5) Previous issue date: 2010 / Resumo: As tubulações de alumínio de saída de água dos motores diesel estão apresentando cavitação, devido ao seu design. Atualmente a tubulação de alumínio de saída de água recebe a anodização dura, porém a liga Al - Si - 10 Mg não é favorável a anodização por ter o silício. O silício, por sua vez, dificulta a formação da camada de óxido e com isso a camada de anodização não será uniforme, principalmente na região interna da tubulação de água. A camada de anodização está sendo mal depositada devido ao processo ser manual e com isso as tubulações de água que apresentaram cavitação foram analisadas em microscópio eletrônico de varredura, a fim de caracterizar a espessura da camada anodizada. Observou-se comparativamente que a camada de anodização não é uniforme. A pintura KTL é um tratamento superficial que consiste em um processo de três etapas, sendo a primeira de um pré-tratamento: desengraxe, lavagem, decapagem e fosfatização. A segunda é a Pintura Eletroforética Catódica (KTL) e por último a terceira que é a cura acelerada em estufa com temperatura e tempo controlado. A pintura KTL foi realizada pela teoria da eletroquímica que se subdivide em quatro fenômenos: Eletrólise, Eletroforese, Eletrocoagulação e por fim a eletroosmose. Na análise realizada comparativamente a camada de KTL é uniforme em toda a extensão da tubulação de alumínio de saída de água dos motores Diesel. Com este resultado comparativo, a pintura KTL se faz necessária na tubulação de alumínio (Al - Si - 10 Mg) de saída de água dos motores Diesel para que se minimize o efeito da cavitação / Abstract: The pipes aluminum water outlet of the diesel engines is experiencing cavitation, due to its design. currently, aluminum pipe water outlet receives the hard anodized, but the Al - Si - Mg 10 is not favorable to have the anodizing because silicio. The silicio, in turn, hinders the formation of the oxide layer and thus the layer of anodizing is not uniform, especially in the inner water pipe. Water pipes that had cavitation were examined in a scanning electron microscope in order to characterize the thickness of the anodized layer. It was noted that the comparatively anodizing layer is not uniform. KTL painting is a surface treatment that consists of a three-step process, the first being a pre-treatment: degreasing, washing, pickling and phosphating. The second is the Cathodic Electrophoretic Painting (KTL) and finally the third which is accelerated healing in a greenhouse with controlled temperature and time. KTL painting was done by the theory of electrochemistry which is divided into four phenomena: Electrolysis, Electrophoresis, Electro coagulation and finally the electroosmosis. In the analysis performed compared to KTL layer is uniform throughout the length of aluminum pipe water outlet of diesel engines. With this result comparison, KTL painting is needed in the tubing of aluminum (Al - Si - 10 Mg) output of diesel engines for water to minimize the effect of cavitation / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Automobilistica

The design of polyethylene (PE) pipelines for applications in the gas, water and chemical process industries has been based on data mainly obtained from stress rupture testing pipes only. In practice, installations are composed of both extruded pipe and injection moulded fittings which are joined by a fusion welding technique and are very often subjected to internal pressures of a fluctuating nature. Several makes of PE pipe systems were therefore obtained and work was undertaken to fully characterise mechanical performance in terms of internal pressure loadings. Butt-welded test specimens comprising pipe lengths and fittings were subjected to both static and fluctuating conditions at 80°C, at pressures resulting in brittle fractures (below the knee on stress rupture curves) and at frequencies not exceeding 7.5 cpm (0.125 Hz). Resulting fracture surfaces were examined to identify sources of crack initiation and mechanisms of failure. Mechanical behaviour of the PE pipe samples was found to be markedly influenced by the grade of plastics compound, the pipe system dimensions, mould designs and methods of processing. Fatigue loading was the most aggressive test method and significant reductions in lifetimes were observed in fittings or joints between pipes and fittings with only modest increases in the frequency of pressurisation. It was also demonstrated that improved stress rupture behaviour did not necessarily lead to better fatigue performance. For the square-wave loading profiles used, an idea of the relevant failure mechanisms in any given system was obtained by comparing experimental Nf values with those predicted from cumulative damage principles based on Nf=τSR/τmax. In all types of system, failure was initiated at a defect residual from processing or jointing. Over 95% of all small diameter pipe fractures originated from inclusions at or close to the inside wall. They were geometrically and elementally analysed and suggestions made as to their possible origin and means of elimination. For one PE a reasonable correlation was obtained, between lifetime under stress rupture or fatigue and the inclusion size as measured in the fracture plane.

No description available.