9 resultados para módulo de ruptura

em Repositório da Produção Científica e Intelectual da Unicamp


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This study focus on the reconfiguration of educational management in Argentina, Brazil, Chile and Mexico, which was promoted by the new logic of social regulation and the new role attributed to the State, considering each country's own historicity. So, the cultural factors that interfere on the dynamics of the 90' school reform are analyzed. Aspects that show the homogeneity or heterogeneity of these reforms in the region, as well as local specificities that block out the concretization of the reform are underlined. It is shown that the historicity that characterizes the educational reform has taken, in each country, a form that can be called, in Mexico, conservative rupture; in Chile, conservative continuity; in Brazil, conservative renovation; and, in Argentina, interrupted rupture. Some conclusions about the impact of educational reform in the selected countries are recuperated through the analysis of 186 academic texts on the subject.

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The aim of this research was to study the effect of chemical additives (lime and Portland cement) associated with sodium silicate on soil in order to obtain compressed soil bricks. Mini panels were constructed with such bricks being their physical and mechanical characteristics determined in laboratory conditions and their behavior evaluated through the association of destructive and non-destructive methods. For this purpose a sandy soil and a finely divided one were added to Portland cement and lime in the dosage of 6% and 10% taken in dry weight basis in relation to the dry soil. The sodium silicate dosage of 4% was also taken in dry weight basis in relation to the dry soil-cement or to the dry soil-lime. The compressed soil bricks were cured in a humidity chamber for 7; 28; 56 and 91 days. The bricks were laid on the fourteenth day to form prismatic mini panels each one with four layers of bricks. After 28; 56 and 91 days the mini panels were submitted to both; ultrasonic and compressive tests to determine its elastic properties (dynamic modulus) and the compressive resistance. The best results in terms of compressive strength, water absorption capacity or dynamic elastic modulus, were reached by the sandy soil added to 10% of Portland cement or lime associated with sodium silicate.

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A base-cutter represented for a mechanism of four bars, was developed using the Autocad program. The normal force of reaction of the profile in the contact point was determined through the dynamic analysis. The equations of dynamic balance were based on the laws of Newton-Euler. The linkage was subject to an optimization technique that considered the peak value of soil reaction force as the objective function to be minimized while the link lengths and the spring constant varied through a specified range. The Algorithm of Sequential Quadratic Programming-SQP was implemented of the program computational Matlab. Results were very encouraging; the maximum value of the normal reaction force was reduced from 4,250.33 to 237.13 N, making the floating process much less disturbing to the soil and the sugarcane rate. Later, others variables had been incorporated the mechanism optimized and new otimization process was implemented .

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Cardboard packing for horticultural products has as main function to protect them. The design of a cardboard packing request the knowledge of the bending stiffens which is depending on the modulus of elasticity. The objective of this work was to calculate the cardboard modulus of elasticity from data obtained in laboratory using physical characterization test, with different methods, and comparing the results with the values obtained experimentally. Ten samples of each cardboard selected for this study were tested in the paper fabrication direction and in its transverse direction. The papers liner and medium resistance to the traction, used to calculate the bending stiffness, was determined in a universal machine test. To obtaining of the bending stiffens the four points test was accomplished. Expressive variations among the methods from which the modulus of elasticity is obtained were observed and that influence the bending stiffness of the structure. The stiffness values obtained experimentally were always greater than the values obtained from analytical method. This difference can be attributed to two factors, the production processes that assurance a larger rigidity than the components separately and the addition of the adhesive layer that is not taken in consideration in the analytic calculations.

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The durability of the cellulose-cement composites is a decisive factor to introduce such material in the market. Polymers have been used in concrete and mortar production to increase its durability. The goal of this work was the physical and mechanical characterization of cellulose-cement composites modified by a polymer and the subsequent durability evaluation. The work also evaluated the dispersion of acrylic polymer in composites made of Pinus caribaea residues. The physical properties observed were water absorption by immersion and bulk density. Rupture modulus and toughness were determined by flexural test. The specimens were obtained from pads, produced by pressing and wet curing. Samples were subjected to accelerated aging tests by repeated wetting and drying cycles and hot-water bath and natural aging. The scanning electron microscopy (SEM) allowed verifying the fiber and composite characteristics along the time. For the composite range analyzed, it was observed the polymer improved the mechanical properties of composites besides a significant decreasing in water absorption. The use of polymer improved the performance of vegetable fiber-cement composites when compared to the conventional mortar, due to water absorption decreasing.

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This paper presents the behavior of three bored piles conducted in diabasic soil submitted to uplift forces. The piles were built at the site for Experimental Studies in Soil Mechanics and Foundations of UNICAMP, located in the city of Campinas, Brazil. Field tests have already been conducted at the site (SPT, CPT, DMT and PMT), as well as laboratory tests by using sample soils taken from a well up to 17 m deep. The water table is not checked until a depth of 17 m. In order to check the behavior of the piles when submitted to uplift forces, slow static load tests were carried out as the recommendations of NBR 12131. The carrying capacity of these piles was also provided by means of theoretical methods, appropriate for uplift forces, and through semi-empirical methods appropriate for compression forces, considering only the portion of lateral resistance. The values estimated by using the considered methods were compared to those obtained by means of load tests. One of the tested piles was extracted from the soil to be the subject of a study on its geometry.

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OBJETIVE: Investigate the cardiopulmonary responses of one strength training session in young women. METHOD: Twenty-three women aged between 18 and 29 years participated in this study. All the volunteers were submitted to the following tests: cardiopulmonary and one-repetition maximum (1-RM). The strength training protocol had emphasis on muscular hypertrophy, three sets from eight to twelve repetitions under 70% of 1-RM, with a one minute thirty-second break between sets. During the training session, the cardiopulmonary variables were measured with a metabolic gas analyzer and a telemetry module. RESULTS: The results of the oxygen consumption in the training session were from 8.43 + 1.76 ml/kg/min and of the heart rate of 108.08 + 15.26 bpm. The results of the oxygen consumption and of the heart rate in the training were lower (p < 0.01) than in the ventilatory threshold and of the oxygen consumption and the heart rate reserves. CONCLUSION: The obtained data show that the present protocol of strength training provided low overload to the cardiopulmonary system of young women.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física