418 resultados para Tunnels
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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A técnica TightRope, que procura aperfeiçoar a estabilização extra-capsular com sutura lateral, por meio da realização de mínimas incisões e criação de túneis ósseos em pontos isométricos, que permitem a inserção de mecanismo que anula o movimento de gaveta, além de reduzir a ocorrência de complicações graves. Dessa forma, objetivou-se avaliar a modificação da técnica TightRope em joelhos de cadáveres caninos com a finalidade de disponibilizar um procedimento simples e de custo reduzido para tratamento da Ruptura do ligamento cruzado cranial (RLCCr). Experimentalmente, foram utilizados 20 membros pélvicos de dez cadáveres caninos, provenientes do setor de patologia da Universidade Norte do Paraná, os quais pesavam entre 6,3 e 24kg. Para estabilização do LCCr, rompido intencionalmente, foi adotada a técnica de TightRope modificada utilizando fio de poliamida, cavilha e emprego de um parafuso ortopédico para proporcionar a fixação óssea. Comparando os valores de deslocamento obtidos durante a realização do movimento de gaveta previamente à ruptura do LCCr e após a realização do procedimento cirúrgico, observou-se que a modificação da técnica TightRope promoveu estabilidade significativa para a maioria (12 de 20) dos joelhos testados (P=0,0033). Contudo, essa estabilidade foi inferior, quando comparada à estabilidade do ligamento intacto.
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The prominent nests mounds of many ant species are one of the most obvious signs of their presence, yet the subterranean architecture of nests is often poorly known. The present work aimed to establish the external and internal structure of nests of a species of leaf-cutting ant, Acromyrmex rugosus rugosus, by either marking the interior of nests with talcum powder, or forming casts with cement. Twelve nests were excavated and surveyed, with eight being marked with talcum powder and four cast with cement. The external and internal structure of the nests was highly variable. The largest and smallest nests had mound areas of 9.89 m(2) and 0.01 m(2) respectively. The number of chambers found ranged from I to 26, with maximum dimensions of between 6 and 70 cm. Chambers were found close to the soil surface (6 cm) down to a maximum depth of 3.75 m. In addition to chambers containing fungus garden, some chambers were found to be empty, filled with soil or filled with waste, the first time this has been recorded in a species of Acromyrmex. The nests of A. rugosus rugosus appear to be unusually complex for the genus, containing a diversity of irregular chambers and tunnels.
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The internal structure of three nests of Atta laevigata was studied in Botucatu city, São Paulo State, Brazil. Two nests were excavated through the opening of trenches and one was cement-moulded to enable a better view of the internal structures. The three nests presented a similar structure, with the depths and number of chambers varying as a function of the loose soil area of the nests. The number of chambers ranged from 1149 to 7864, reaching as deep as 7 m underground. Chamber volume ranged from 0.03 to 511. The foraging tunnels extended as far as 70m from the loose soil region. The nests of this species are the deepest within the genus Atta and have the highest number of chambers.
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Broiler production in Brazil has turned into a very competitive activity in the late years. Constant innovation leads to higher productivity maintaining the same cost of production, which is a desirable situation. Lately one characteristic for broiler housing in Brazil has been the increase in birds density requiring the use of controlled environment through the use of fan and fogging systems in order to achieve better birds productive performance. Most Brazilian producer already uses cooling equipment however it is still unknown the right way to control the wind speed and direction towards the birds. This present research has the objective to evaluate the effect of the wind speed on the heat transfer from the birds to the environment for broilers at 27 days old. There was used 200 birds, placed in a wind tunnel measuring 1.10 m high by 1.10m wide x 10.0 m of length, and the birds density varied from 9, 16 and 20 birds/m 2. Two wind speed were simulated 340 rpm (1.0 m/s) and 250 rpm (0.3 m/s). The increase in the wind velocity related to the smaller bird densityled to a higher heat loss and to a more uniform temperature distribution in its exposed areas.
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This work was carried out to determine the internal and external structures of Atta bisphaerica (Forel) nests. Six nests were excavated and during excavation, all data referring to chambers and tunnels were recorded. Three nests had been internally cement-moulded, which enabled a better view of the chamber and tunnel structures. Atta bisphaerica nests presented a similar structural pattern, varying only in the number of chambers as a function of external mound area. Chambers were spherical with two communication tunnels. Internal tunnels had an elliptical section, sometimes circular, indirectly linked to chambers through ramifications and directly through short tunnels. Entrance holes were linked to the area of highest chamber concentration by tunnels from the elliptical section, which led to the nest in a radial manner. Knowledge of the colony's three-dimensional architecture permits successful application of chemical control processes, reduces the quantity of product applied, and consequently diminishes costs and environmental damage.
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This study aimed to verify the effects of four different minimum soil watler potentials (-30, -40, -50 e -70 kPa) and two different plastic tunnel positions (North-South and East-West) on net melon yield. The results showed that in the East-West position the yield and fruit weight were higher than in the North-South position. The highest yields of melon crop were obtained from -30 kPa. to -40 kPa minimum soil water potential.
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In view of the limited number of drill holes, interpolation of the data becomes a relatively complex task. In this study, we sought to make estimates associated with lithological types, since a quantification based on lithology can be extracted from the empty spaces in the sampling. For example, QBarton is always below the median of the biotitic litotype, information which can be used in the elaboration of geostatistical models in situations where samples are lacking. To overcome bias in the data, required by geostatistical conceptualization, we worked with the residuals obtained from the adjustment of a surface and the observed values, for the variographic analysis. The final results made possible a more optimized evaluation of the final costs required for the construction project.
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The necessity of adapting the standardized fan models to conditions of higher temperature has emerged due to the growth of concerning referring to the consequences of the gas expelling after the Mont Blanc tunnel accident in Italy and France, where even though, with 100 fans in operation, 41 people died. However, since then, the defied solutions have pointed to aerodynamic disadvantages or have seemed nonappropriate in these conditions. The objective of this work is to present an alternative to the market standard fans considering a new technology in constructing blades. This new technology introduces the use of the stainless steel AISI 409 due to its good adaptation to temperatures higher than 400°C, particularly exposed to temperatures of gas exhaust from tunnels in fire situation. Furthermore, it presents a very good resistance to corrosion and posterior welding and pressing, due to its alloyed elements. The innovation is centered in the process of a deep drawing of metallic shells and posterior welding, in order to keep the ideal aerodynamic superficies for the fan ideal performance. On the other hand, the finite element method, through the elasto-plastic software COSMOS permitted the verification of the thickness and structural stability of the blade in relation to the aerodynamic efforts established in the project. In addition, it is not advisable the fabrication of blades with variable localized thickness not even, non-uniform ones, due to the verified concentration of tensions and the difficulties observed in the forming. In this way, this study recommends the construction of blades with uniform variations of thickness. © 2007 Springer.
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Aerodynamic balances are employed in wind tunnels to estimate the forces and moments acting on the model under test. This paper proposes a methodology for the assessment of uncertainty in the calibration of an internal multi-component aerodynamic balance. In order to obtain a suitable model to provide aerodynamic loads from the balance sensor responses, a calibration is performed prior to the tests by applying known weights to the balance. A multivariate polynomial fitting by the least squares method is used to interpolate the calibration data points. The uncertainties of both the applied loads and the readings of the sensors are considered in the regression. The data reduction includes the estimation of the calibration coefficients, the predicted values of the load components and their corresponding uncertainties, as well as the goodness of fit.
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In the neighborhood of the city of Boqueirão do Leão (State of Rio Grande do Sul, Brazil) a set of three big-sized tunnels has been found. One of the tunnels is only partially filled with sand and accessible along its entire length. It is horizontal, slightly sinuous, 36 m long, up to 4.2 m wide and up to 2.0 m high. The surface morphology of the walls is composed of anthropogenic marks, speleothems, black incrustations and traces like digging scratches and smoothed surfaces. The 2nd tunnel has its entrance blocked by sand and sandstone cobbles, but the end of the tunnel is only partially clogged and therefore accessible. This accessible portion is 12 m long, 3 m wide and 1.5 m high. The 3rd tunnel is completely filled and collapsed and is nowadays only indicated by concave roof features at its end. The general features of the tunnel system and the analysis of the surface morphology of the walls of the accessible portions permit to conclude that the tunnels were produced by ground sloths of the Cenozoic South American megafauna. The size of the tunnels suggests that its excavation was gradually carried out by successive generations of sloth herds, and not by a single individual animal. The primary function of the tunnels probably was not protection from predators, which had easy access to structures of this size, but to shelter during a drier climate. However, it is not yet possible to relate the tunnels to a specific ground sloth genus, a task that depends on the discovery of better-preserved tunnel systems. © 2013 by the Sociedade Brasileira de Paleontologia.
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The present study was designed to compare Day 14 bovine embryos that were produced entirely in vitro using the post-hatching development (PHD) system with in vivo-derived embryos without or with transient PHD culture from Day 7 to Day 14. Embryos on Day 14 were used for sex determination and gene expression analysis of PLAC8, KRT8, CD9, SLC2A1, SLC2A3, PGK1, HSF1, MNSOD, HSP70 and IFNT using real-time quantitative (q) polymerase chain reaction (PCR). First, Day 7 in vivo-and in vitro-produced embryos were subjected to the PHD system. A higher rate of survival was observed for in vitro embryos on Day 14. Comparing Day 14 embryos produced completely in vivo or completely in vitro revealed that the mean size of the former group was greater than that of the latter (10.29±1.83 vs 2.68±0.33mm, respectively). Expression of the HSP70 and SLC2A1 genes was down-and upregulated, respectively, in the in vitro embryos. The present study shows that in vitro embryos cultured in the PHD system are smaller than in vivo embryos and that of the 10 genes analysed, only two were differentially expressed between the two groups. These findings indicate that, owing to the poor survival rate, the PHD system is not reliable for evaluation of in vitro embryo quality. © 2013 CSIRO.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC