857 resultados para Dimensionamento de estruturas


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The Itaqui Granitoid Complex is a drop shaped WNW-ESE trending intrusion with its head' at west. Its contacts with the low-grade metamorphic rocks of the Sao Roque Group are intrusive at west, northwest, north and northeast, and tectonic at south and northeast. The complex is built up by four main intrusive phases which characterize a rising and unroofing process. Petrographically the Itaqui granite comprises five distinct magmatic associations in nine igneous units. -from English summary

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BACKGROUND: Ultrasonography (US), Computed Tomography (CT), and Magnetic Resonance imaging (MR) were compared for the staging of renal tumors. The differences between these imaging techniques were also studied for their ability to detect adenopathies, vascular invasion, distant intra-abdominal metastases, and particularly adjacent organ invasion. METHODS: Thirty-one patients with solid or complex renal masses were prospectively studied using US, CT, and MR. Differences between the results obtained were studied using the COCHRAN G test and the McNEMAR test. The sensitivity and specificity of each diagnostic technique were compared against a gold standard of the surgical and histopathological findings. RESULTS: The following sensitivities were obtained: For the detection of adenopathy, US 63.6%, CT and MR 90.9%. For vascular invasion, US 42.8%, CT and MR 85.7%. For the adjacent organ invasion, US 28.5%, CT 85.7%, and MR 71.4%. Some of the criteria that suggest invasion of adjacent structures include: the envelopment of the adjacent structures by the tumor, tumor extension into the adjacent structures with an irregular appearance, and alterations in shape, size, and density of adjacent structures. Loss of fat planes between the tumor and adjacent structures is not a sign of tumor invasion. CONCLUSIONS: Significant differences were found in the detection capacity of US in relation to CT and MR, which were similar. All three techniques were highly sensitive and specific only in the detection of distant abdominal metastases. In addition to the accuracy of these diagnostic modalities for the detection and staging of tumors, invasiveness, risks and cost should be considered in relation to relative costs and benefits.

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One of the great challenges of structural dynamics is to ally structures lighther and stronger. The great difficulty is that light systems, in general, have a low inherent damping. Besides, they contain resonance frequencies in the low frequency range. So, any external disturbance can excite the system in some resonance and the resulting effect can be drastic. The methodologies of active damping, with control algorithms and piezoelectric sensors and actuators coupled in a base structure, are attractive in current days, in order to overcome the contradictory features of these requeriments. In this sense, this article contributes with a bibliographical review of the literature on the importance of active noise and vibration control in engineering applications, models of smart structures, techniques of optimal placement of piezoelectric sensors and actuators and methodologies of structural active control. Finally, it is discussed the future perspectives in this area.

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The designs of filters made by granular material or textile are mainly based on empirical or semi empirical retention criteria according to Terzaghi proposal, which compares particle diameter of the soil base with the filter porous spaces. Silveira in 1965, proposed one rational design retention criteria based on the probability of a particle from the soil base, carried by one dimensional flow, be restrained by the porous of the filter while trying to pass through its thickness. This new innovating theory, besides of being very simple, it is not frequently used for granular filters since the necessary parameters for the design has to be determine for each natural material. However, for textile this problem no longer exists because it has quality control during manufacturing and the necessary characteristics properties of the product are specify in the product catalog. This work presents one adaptation of the Silveira theory for textile filters and the step-by-step procedure for the determination of the characteristics properties of the textile products necessary for the design. This new procedure permits the determination of the confiability level of retention that one specific particle diameter form the soil base has for one specified textile. One complete example is presented to demonstrate the simplicity of the method proposed and how the textile characteristics are obtained.

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In this paper, some new constraints and an extended formulation are presented for a Lot Sizing and Scheduling Model proposed in the literature. In the production process considered a key material is prepared and is transformed into different final items. The sequencing decisions are related to the order in which the materials are processed and the lot sizing decisions are related to the final items production. The mathematical formulation considers sequence-dependent setup costs and times. Results of the computational tests executed using the software Cplex 10.0 showed that the performance of the branch-and-cut method can be improved by the proposed a priori reformulation.

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Malvaceae shows a rich morphological diversity of secretory structures, which are of great ecological and taxonomical relevance. Nonetheless, until the present moment, studies on the secretory structures of the studied species were not found. Pavonia alnifolia A.St.-Hil. is endangered species of extinction with restricted distribution within the restingas of Rio the Janeiro and Espírito Santo, Brazil. The species were collected from the former and usual techniques on plant anatomy and histochemistry were performed. Anatomical and histochemical studies of the secretory structures of Pavonia alnifolia are showed in this work. The presence of external and internal secretory structures of mucilage in many organs, idioblasts of phenolic and lipid substances and floral nectaries what is a very important adaptative survival mechanism of the species in the restinga environment. The secretion produced by nectaries is envolved with maintenance of interations with visiting insects, what constitutes a good model to experimental studies with an ecological approach.

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Dance activities were administered to a group of deaf adolescents via visual and auditory stimuli in order to improve their perceptions of monotonic rhythmic structures. Status of psychomotor development was also assessed before and after participation in the program. Twenty deaf adolescents (ages between 12 and 13 years) were divided into two groups, experimental (EG) and control (CG). Before and after participating in the program for 26 weeks, participants were evaluated in rhythmical tasks adapted from the classical test of M. Stambak. The tasks included the perception of drum beats, actually viewed hit movements, or heard via a sound amplifier. Psychomotor tests were administered only to the EG. The period of practice with dance activities changed the individuals' performance in the monotonic rhythmic test. Also, the success rate improved in both, visual and auditory input tasks. Individuals in the CG showed no changes in performance. For the EG, in the post-test, the status of psychomotor development was six months below the target age of the tests (i.e., 11 years). Findings suggested that dance activities can change deaf individuals' auditory perception of rhythmic structures. Participation in such a program can also positively affect psychomotor development. © FTCD/FIP-MOC.

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In this paper, capacitated lot sizing problems in which the classical lot sizing decisions are made considering the transportation costs of the manufactured products were studied. These costs are related to the necessary number of pallets or trucks to pack and/or transport the products from the factory to the warehouse. Three extensions of a mixed integer linear programming model from the literature are considered, representing general cases that are commonly found in companies. These models are tested and evaluated using an optimization package, and a Lagrangian heuristic was developed for one of the extensions proposed.

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Pós-graduação em Matemática - IBILCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Matemática - IBILCE

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

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Pós-graduação em Estudos Linguísticos - IBILCE