24 resultados para Transportation.
em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"
Resumo:
This study evaluated stress indicators of juvenile piau (Leporinus friderici) during and after a 4-hour transportation in order to establish an appropriate transportation protocol for this type of fish. Fish were transported in plastic bags (133.1 g/L) and sampled before loading, during 1, 2, 3 and 4 h and after transportation (2, 6, 12 and 24 h). Blood samples were analyzed for cortisol and glucose levels, hematocrit, hemoglobin level, number and mean corpuscular volume of erythrocytes. Water pH, dissolved oxygen, temperature and ammonia were monitored before, during and after transportation. No mortality was observed through the experiment. Ammonia levels increased throughout transportation, but the low pH values kept NH3 in safe levels for fish. Cortisol levels increased within 4 h of transportation, and returned to control condition 2 h after arrival. Plasma glucose increased within one hour of transportation, reaching peak value within 4 h and returning to initial condition 2 h after arrival. Erythrocyte number and hemoglobin levels showed the lowest levels 2 h after arrival, and mean corpuscular volume increased during transportation, decreasing at 12 and 24 h after arrival. Transporting piau is stressful, but fish recover the initial condition in short time, showing tolerance to the changes in the water quality parameters.
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The purpose of this paper is to describe the benefits of sugar cane ethanol in Brazil, appointing the productivity of this type of fuel based on hectares of plantation, its carbon dioxide cycle and the contribution to reduce the greenhouse effect. In the following step the uses of ethanol for hydrogen production by steam reforming is analyzed and some comparison with natural gas steam reforming is performed. The sugar cane industry in Brazil, in a near future, in the hydrogen era, could be modified according to our purpose, since besides the production of sugar, and ethylic and anhydric alcohol, Brazilian sugar cane industry will also be able to produce biohydrogen.Fuel cells appear like a promising technology for energy generation. Among several technologies in the present, the PEMFC (proton exchange membrane fuel cell) is the most appropriate for vehicles application, because it combines durability, high power density, high efficiency, good response and it works at relatively low temperatures. Besides that it is easy to turn it on and off and it is able to support present vibration in vehicles. A PEMFC's problem is the need of noble catalysts like platinum. Another problem is that CO needs to be in low concentration, requiring a more clean hydrogen to avoid fuel cell deterioration.One part of this paper was developed in Stockholm, where there are some buses within the CUTE (clean urban transport for Europe) project that has been in operation with FC since January 2004. Another part was developed in Guaratingueta, Brazil. Brazil intends to start up a program of FC buses. As conclusion, this paper shows the economical analysis comparing buses moved by fuel cells using hydrogen by different kinds of production. Electrolyze with wind turbine, natural gas steam reforming and ethanol steam reforming. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
An 8-year-old male Boxer with a severely contaminated open fracture of the left radius and ulna fracture, produced by a helicopter propeller, was treated using bone transport by the Ilizarov method. Extensive diaphyseal bone loss and soft-tissue vascular damage were present. The radius and ulna were stabilised with an Ilizarov ring external fixator. The bone defect was partially shortened and restored by gradual transport of a bone segment created from proximal segments of the radius and ulna. The external fixator was removed 4fi months after the beginning of the latency period, due to instability caused by osteolysis around the wires. A cast was placed for 3 weeks. Although the bone transport had resulted in formation of approximately 4 cm of bone, the antebrachium showed approximately 50% shortening when compared to the contralateral limb. The infection was eradicated, and the dog was able to bear weight on the operated limb when walking.
Resumo:
Neste trabalho estuda-se um problema de dimensionamento de lotes e distribuição que envolve além de custos de estoques, produção e preparação, custos de transportes para o armazém da empresa. Os custos logísticos estão associados aos contêineres necessários para empacotar os produtos produzidos. A empresa negocia um contrato de longo prazo onde um custo fixo por período é associado ao transporte dos itens, em contrapartida um limite de contêineres é disponibilizado com custo mais baixo que o custo padrão. Caso ocorra um aumento ocasional de demanda, novos contêineres podem ser utilizados, no entanto, seu custo é mais elevado. Um modelo matemático foi proposto na literatura e resolvido utilizando uma heurística Lagrangiana. No presente trabalho a resolução do problema por uma heurística Lagrangiana/surrogate é avaliada. Além disso, é considerada uma extensão do modelo da literatura adicionando restrições de capacidade e permitindo atraso no atendimento a demanda. Testes computacionais mostraram que a heurística Lagrangiana/surrogate é competitiva especialmente quando se têm restrições de capacidade apertada.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In this paper, a load transportation system in platforms or suspended by cables is considered. It is a monorail device and is modelled as an inverted pendulum built on a car driven by a DC motor. The governing equations of motion were derived via Lagrange's equations. In the mathematical model we consider the interaction between the DC motor and the dynamical system, that is, we have a so-called non-ideal periodic problem. The problem is analysed and we also developed an optimal linear control design to stabilize the problem.
Resumo:
In this paper, a loads transportation system in platforms or suspended by cables is considered. It is a monorail device and is modeled as an inverted pendulum built on a car driven by a dc motor the governing equations of motion were derived via Lagrange's equations. In the mathematical model we consider the interaction between the dc motor and the dynamical system, that is, we have a so called nonideal periodic problem. The problem is analyzed, qualitatively, through the comparison of the stability diagrams, numerically obtained, for several motor torque constants. Furthermore, we also analyze the problem quantitatively using the Floquet multipliers technique. Finally, we devise a control for the studied nonideal problem. The method that was used for analysis and control of this nonideal periodic system is based on the Chebyshev polynomial exponsion, the Picard iterative method, and the Lyapunov-Floquet transformation (L-F transformation). We call it Sinha's theory.
Resumo:
A comparative study of aggregation error bounds for the generalized transportation problem is presented. A priori and a posteriori error bounds were derived and a computational study was performed to (a) test the correlation between the a priori, the a posteriori, and the actual error and (b) quantify the difference of the error bounds from the actual error. Based on the results we conclude that calculating the a priori error bound can be considered as a useful strategy to select the appropriate aggregation level. The a posteriori error bound provides a good quantitative measure of the actual error.
Resumo:
Aggregation disaggregation is used to reduce the analysis of a large generalized transportation problem to a smaller one. Bounds for the actual difference between the aggregated objective and the original optimal value are used to quantify the error due to aggregation and estimate the quality of the aggregation. The bounds can be calculated either before optimization of the aggregated problem (a priori) or after (a posteriori). Both types of the bounds are derived and numerically compared. A computational experiment was designed to (a) study the correlation between the bounds and the actual error and (b) quantify the difference of the error bounds from the actual error. The experiment shows a significant correlation between some a priori bounds, the a posteriori bounds and the actual error. These preliminary results indicate that calculating the a priori error bound is a useful strategy to select the appropriate aggregation level, since the a priori bound varies in the same way that the actual error does. After the aggregated problem has been selected and optimized, the a posteriori bound provides a good quantitative measure for the error due to aggregation.
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A method for optimal transmission network expansion planning is presented. The transmission network is modelled as a transportation network. The problem is solved using hierarchical Benders decomposition in which the problem is decomposed into master and slave subproblems. The master subproblem models the investment decisions and is solved using a branch-and-bound algorithm. The slave subproblem models the network operation and is solved using a specialised linear program. Several alternative implementations of the branch-and-bound algorithm have been rested. Special characteristics of the transmission expansion problem have been taken into consideration in these implementations. The methods have been tested on various test systems available in the literature.
Resumo:
The usefulness of the application of heuristic algorithms in the transportation model, first proposed by Garver, is analysed in relation to planning for the expansion of transmission systems. The formulation of the mathematical model and the solution techniques proposed in the specialised literature are analysed in detail. Starting with the constructive heuristic algorithm proposed by Garver, an extension is made to the problem of multistage planning for transmission systems. The quality of the solutions found by heuristic algorithms for the transportation model is analysed, as are applications in problems of planning transmission systems.
Resumo:
Introduction: The aim of this study was to assess the occurrence of apical root transportation after the use of Pro Taper Universal rotary files sizes 3 (F3) and 4 (F4). Methods: Instruments were worked to the apex of the original canal, always by the same operator. Digital subtraction radiography images were produced in buccolingual and mesiodistal projections. A total of 25 radiographs were taken from root canals of human maxillary first molars with curvatures varying from 23-31 degrees. Quantitative data were analyzed by intraclass correlation coefficient and Wilcoxon nonparametric test (P = .05). Results: Buccolingual images revealed a significantly higher degree of apical transportation associated with F4 instruments when compared with F3 instruments in relation to the original canal (Wilcoxon test, P = .007). No significant difference was observed in mesiodistal images (P = .492). Conclusions: F3 instruments should be used with care in curved canals, and F4 instruments should be avoided in apical third preparation of curved canals. (J Endod 2010;36:1052-1055)
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The objective of this experiment was to test the efficacy of a probiotic (Efinol (R) L) during transportation of marbled hatchetfish, Carnegiella strigata. Wild specimens were captured from a small stream and transported for 24 h in plastic fish boxes with a probiotic (10 mg L-1) and probiotic-free water. The boxes were sampled at 3. 12 and 24 h of transport. At the end of the experiment, the survival rate was close to.100%) in both treatments. Dissolved oxygen diminished with time in both treatments, but the probiotic group had significantly higher levels. Conductivity. pH and ammonia increased significantly during the transport. demonstrating higher levels in the probiotic-free group. Fish from both treatments presented very high net Na+ and K+ effluxes after 3 h of transport. At 24 h, net K+ effluxes in fish of the probiotic treatment reached values close to zero and a significantly lower Na+ efflux was observed. Cortisol levels in both treatments at 3 and 12 h were significantly higher than that in control samples. Higher body cortisol levels were observed in the probiotic-frec group than that in the probiotic group at 3 and 12 h. The results demonstrate that addition of a probiotic during fish transport improves water quality and leads to fish presenting a lower stress response intensity.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The increased demand for juvenile tambaqui Colossoma macropomum for grow-out ponds and stocking programs in the Amazon state of Brazil has increased the transportation of this species. This study was designed to determine the optimum density of juvenile tambaqui during transportation in closed containers. Fish (51.9 ± 3.3 g and 14.9 ± 0.4 cm) were packed in sealed plastic bags and transported for 10 h at four densities: 78, 156, 234, and 312 kg/m3. After transportation, fish from each density were kept in separate 500-L tanks for 96 h. Mortality, 96-h cumulative mortality, water quality, and blood parameters (hematocrit, plasma cortisol, and glucose) were monitored. Fish mortality after transportation was significantly lower at densities of 78 and 156 kg/m3 than at 234 and 312 kg/m3. Cumulative mortality was significantly lower at a density of 78 kg/m3. Dissolved oxygen after 10 h of transportation remained high at a density of 78 kg/m3, but reached critically low values at all other densities. Ammonia concentration was highest at the lowest density and was lower at higher densities. Carbon dioxide concentration was lowest at the density of 78 kg/m3 but higher in the other treatments. Plasma glucose and cortisol increased significantly immediately after transportation at densities of 156, 234, and 312 kg/m3, returning to control values by 24 h. The best density for juvenile tambaqui during a 10-h transportation haul in a closed container was 78 kg/m3. At this density there was no fish mortality, water quality was kept within acceptable values, and fish were not stressed.