829 resultados para Plastic pipes


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We analyzed the differences between irrigated and non-irrigated plants of three congeneric Styrax species that present distinct distribution patterns in the physiognomies of the Cerrado vegetation in Brazil. Styrax ferrugineus showed a stomatal conductance (gs) unresponsive to soil water deficit in potted plants. This may explain the high gas exchange and photochemical efficiency found in this species, which is well adapted to the Cerrado sensu stricto (s. str.), a savanna-type vegetation. S. camporum, which is widely distributed in the Cerrado sensu lato (s. l.) areas, was the only species that exhibited increased intrinsic water use efficiency on the days of maximum water deficit. This result distinguishes S. camporum from S. pohlii, which is a forest species, since the gs of both species decreased during the days of maximum water stress. In contrast to other studies, we propose that instantaneously measured traits, such as leaf gas exchange rates and chlorophyll fluorescence, may be used to detect non-plastic performances in response to environmental stress, helping explain distinct geographical distributions of congeneric species in the Cerrado vegetation. © 2013 Springer-Verlag Berlin Heidelberg.

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In this work the turbulent flow of the Non-Newtonian Carreau-Yasuda fluid will be studied. A skin friction equation for the turbulent flow of Carreau-Yasuda fluids will be derived assuming a logarithmic behavior of the turbulent mean velocity for the near wall flow out of the viscous sub layer. An alternative near wall characteristic length scale which takes into account the effects of the relaxation time will be introduced. The characteristic length will be obtained through the analysis of viscous region near the wall. The results compared with experimental data obtained with Tylose (methyl hydroxil cellulose) solutions showing good agreement. The relations between scales integral and dissipative obtained for length, time, velocity, kinetic energy, and vorticity will be derived for this type of fluid. When the power law index approach to unity the relations reduces to Newtonian case.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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CONTEXTUALIZAÇÃO:O manuseio de materiais está ainda presente nos setores industriais e é associado a lesões na coluna lombar e membros superiores. A inserção de alças em caixas industriais é uma forma de reduzir os riscos relacionados à tarefa, porém a posição e a angulação das alças, que são fatores importantes para o conforto e segurança durante o manuseio, são ainda pouco investigadas objetivamente.OBJETIVOS:Comparar o manuseio de uma caixa comercial e de protótipos com alças e avaliar seus efeitos na postura de membros superiores, atividade elétrica muscular e percepção de agradabilidade em diferentes empunhaduras durante manuseio entre diferentes alturas.MÉTODO:Trinta e sete voluntários saudáveis avaliaram as alças dos protótipos que possibilitavam mudança nas posições (superior e inferior) e angulações (0°, 15° e 30º). Os movimentos dos punhos, cotovelos e ombros foram avaliados por meio da eletrogoniometria e inclinometria. A atividade elétrica muscular dos extensores do punho, bíceps braquial e porção superior do trapézio foi avaliada por um eletromiógrafo portátil. Os registros de movimento e atividade elétrica muscular foram sincronizados. Aspectos subjetivos de agradabilidade foram avaliados por meio de uma escala visual analógica.RESULTADOS E CONCLUSÕES:Os protótipos com alças inclinadas em 30° apresentaram as melhores avaliações de agradabilidade, posturas mais neutras de punho, menores níveis de atividade eletromiográfica do trapézio superior e menores ângulos de elevação dos braços. Os diferentes métodos de medida se mostraram complementares para a avaliação dos membros superiores durante as tarefas de manuseio.

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The establishment of laboratory colonies of ticks is often hampered by their lack of adaptation to alternative hosts. The aim of this study was to artificially feed partially engorged Dermacentor (Anocentor) nitens females through plastic tips, and to identify what are the optimal conditions of application of this technique to get as much as possible close to the natural conditions. The technique of artificial feeding through plastic tips allowed the engorgement of D. nitens ticks to a final weight within the normal range for the species. (C) 2014 Published by Elsevier GmbH.

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In this work a study about the mechanical properties of the API 5L X70 steel, with or without heat treating, has been made, with the intetion of assess the influence of cooling after the austenitization heat treating by air cooling (normalizing) and a rapid cooling with oil (tempering). This steel is known by high strength and ductility values and it is commonly used in the manufacture of oil pipes. The growing energy demand encouraged the study and manufacture of this material. Although this microalloyed dispense subsequent heat treatings, it was proven that its implementation is very advantageous for this type of application, improving hardness and plastic stability. It was also assessed that the faster the cooling rate is, the better will be these properties

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The aim of this in vitro study was to use strain gauge (SG) analysis to compare the effects of the implant-abutment joint, the coping, and the location of load on strain distribution in the bone around implants supporting 3-unit fixed partial prostheses. Three external hexagon (EH) implants and 3 internal hexagon (IH) implants were inserted into 2 polyurethane blocks. Microunit abutments were screwed onto their respective implant groups. Machined cobalt-chromium copings and plastic copings were screwed onto the abutments, which received standard wax patterns. The wax patterns were cast in a cobalt-chromium alloy (n = 5): group 1 = EH/machined. group 2 = EH/plastic, group 3 = IH/machined, and group 4 = IH/plastic. Four SGs were bonded onto the surface of the block tangentially to the implants. Each metallic structure was screwed onto the abutments and an axial load of 30 kg was applied at 5 predetermined points. The magnitude of microstrain on each SG was recorded in units of microstrain (mu epsilon). The data were analyzed using 3-factor repeated measures analysis of variance and a Tukey test (alpha = 0.05). The results showed statistically significant differences for the type of implant-abutment joint, loading point, and interaction at the implant-abutment joint/loading point. The IH connection showed higher microstrain values than the EH connection. It was concluded that the type of coping did not interfere in the magnitude of microstrain, but the implant/abutment joint and axial loading location influenced this magnitude.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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In this research the aim was produce and evaluate a plastic composite using recycled polypropylene (PP) and fibers from sugarcane bagasse residues (SC), without the use of additives. This analysis was based on laboratorial tests for physical and mechanical characterization, according to the standards ASTM D256-00, D638-101 and D570-98 were analyzed: water absorption, thickness swelling, impact resistance, tensile strength and its correspondent deformation. For comparison it was elaborated three different compositions: 100% PP; 80% PP+20%SC; 70%PP+30%SC. The results indicate a positive correlation with the content of fiber and water absorption and thickness swelling. In the tension tests, the composites with fibers increase the value of resistance for physical efforts, bringing advantages as durability and integrity of the material, showing a viability of the composites.

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In this research the aim was produce and evaluate a plastic composite using recycled polypropylene (PP) and fibers from sugarcane bagasse residues (SC), without the use of additives. This analysis was based on laboratorial tests for physical and mechanical characterization, according to the standards ASTM D256-00, D638-101 and D570-98 were analyzed: water absorption, thickness swelling, impact resistance, tensile strength and its correspondent deformation. For comparison it was elaborated three different compositions: 100% PP; 80% PP+20%SC; 70%PP+30%SC. The results indicate a positive correlation with the content of fiber and water absorption and thickness swelling. In the tension tests, the composites with fibers increase the value of resistance for physical efforts, bringing advantages as durability and integrity of the material, showing a viability of the composites.

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Despite the growing concern in seeking more sustainable energy sources, oil demand is likely to grow in coming years. To keep up with this growth, the oil industry has increasingly invested in innovation and efficiency. Knowing that, new technologies have been developed to explore deeper waters, without giving up the best practices in worldwide operational safety. The use of rigid pipelines in deepwater offshore facilities is increasing quickly and because of this, the ways of storing and launching pipe have been studied and perfected. In this paper the Bauschinger effect on API 5L X70 steel was analyzed proving that there was a reduction in yield strength when an effort was applied in a previous direction, then an effort was then applied in the opposite direction. To observe this phenomenon, the tensile test was conducted to determine the mechanical properties of the base metal, such as yield stress, tensile strength, elasticity and maximum tensile, so then compare it with the results obtained in the Bauschinger Effect Test. The analysis results showed that the steel had high resistance, with good plastic deformation capacity without failing, well-defined yield point, showing itself appropriate for the operation of oil and gas pipes

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Research has provided no definitive answers on whether PET plastic bottles or aluminum cans are a more environmentally sustainable choice as soda containers. This paper researches the fuel used in recycling each of these materials from Yellowstone National Park to processing locations. The data is used to determine which of these alternatives use less fuel in this process. It was found that plastics use more fuel when transported from Yellowstone National Park to the processing center. Aluminum uses less fuel per ton to transport from Yellowstone to the processing center. The conclusions from this research may have implications on which material would be advised to use in selling soda in Yellowstone National Park.

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Despite the growing concern in seeking more sustainable energy sources, oil demand is likely to grow in coming years. To keep up with this growth, the oil industry has increasingly invested in innovation and efficiency. Knowing that, new technologies have been developed to explore deeper waters, without giving up the best practices in worldwide operational safety. The use of rigid pipelines in deepwater offshore facilities is increasing quickly and because of this, the ways of storing and launching pipe have been studied and perfected. In this paper the Bauschinger effect on API 5L X70 steel was analyzed proving that there was a reduction in yield strength when an effort was applied in a previous direction, then an effort was then applied in the opposite direction. To observe this phenomenon, the tensile test was conducted to determine the mechanical properties of the base metal, such as yield stress, tensile strength, elasticity and maximum tensile, so then compare it with the results obtained in the Bauschinger Effect Test. The analysis results showed that the steel had high resistance, with good plastic deformation capacity without failing, well-defined yield point, showing itself appropriate for the operation of oil and gas pipes

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Microplastics are omnipresent in the oceans and generally have negative impacts on the biota. However, flotsam may increase the availability of hard substrates, which are considered a limiting resource for some oceanic species, e.g. as oviposition sites for the ocean insect Halobates. This study describes the use of plastic pellets as an oviposition site for Halobates micans and discusses possible effects on its abundance and dispersion. Inspection of egg masses on stranded particles on beaches revealed that a mean of 24% (from 0% to 62%) of the pellets bore eggs (mean of 5 and max. of 48 eggs per pellet). Most eggs (63%) contained embryos, while 37% were empty egg shells. This shows that even small plastic particles are used as oviposition site by H. micans, and that marine litter may have a positive effect over the abundance and dispersion of this species. (C) 2012 Elsevier Ltd. All rights reserved.

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The quality of plastic films used for horizontal silos is important to limit losses in the upper silage layer. The aim of this work was to study the effectiveness of different plastic films in reducing the top losses in maize silage. The following treatments were evaluated: (i) coextruded polyethylene/polyamide oxygen barrier film (OB), (ii) polyethylene film (PE), (iii) polyvinyl chloride film (PVC), and (iv) coextruded PE/polyvinyl alcohol film (PVOH). These treatments differed according to oxygen permeability with values of 75, 722, 982 and 289 cm(3) m(-2) per 24 hour respectively. OB and PVOH films had better temperature and fermentation profiles than the more permeable films. The OB film was effective in reducing the dry-matter (DM) losses during storage (82 g kg(-1)), and the PVOH film had an intermediate value of DM loss (101 g kg(-1)). PE and PVC films had higher losses (138 and 145 g kg(-1) respectively). Oxygen permeability of the films promoted a positive correlation with DM losses (P < 0.05; r2 = 0.945). The results indicate that O2 permeability through the plastic film is a crucial factor for maintaining silage quality in the upper layer of the silo when it is perfectly sealed.