Validación de un test de natación, evaluando la velocidad aeróbica máxima (VAM) para calcular los ritmos de entrenamiento para triatletas y nadadores.

Resumen tomado de la publicación

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Material para la enseñanza de las matemáticas a niños de cuatro y cinco años partiendo del situaciones-tipo de aprendizaje de la vida real y de sus representaciones mentales. Para cuatro años las actividades se estructuran en cinco campos de aprendizajes diferentes: Clasificación, que le ayuda a diferenciar la forma, el tamaño y el color y que la organización de los objetos según sus diferencias y semejanzas; La abstración del atributo cantidad, El Contaje, Historias y Grafías numéricas. Para cinco años se dividen en Clasificación, Historias, Contaje, Seriación, Correspondencia, Reconocimiento de grafías y Composición y descomposición de cantidades.

Fórmulas para calcular perímetros de figuras planas : unidad didáctica.

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El artículo forma parte de un monográfico dedicado a contextos culturales para la actividad matemática

Uma nova forma de calcular os centros dos Clusters em algoritmos de agrupamento tipo fuzzy c-means

Clustering data is a very important task in data mining, image processing and pattern recognition problems. One of the most popular clustering algorithms is the Fuzzy C-Means (FCM). This thesis proposes to implement a new way of calculating the cluster centers in the procedure of FCM algorithm which are called ckMeans, and in some variants of FCM, in particular, here we apply it for those variants that use other distances. The goal of this change is to reduce the number of iterations and processing time of these algorithms without affecting the quality of the partition, or even to improve the number of correct classifications in some cases. Also, we developed an algorithm based on ckMeans to manipulate interval data considering interval membership degrees. This algorithm allows the representation of data without converting interval data into punctual ones, as it happens to other extensions of FCM that deal with interval data. In order to validate the proposed methodologies it was made a comparison between a clustering for ckMeans, K-Means and FCM algorithms (since the algorithm proposed in this paper to calculate the centers is similar to the K-Means) considering three different distances. We used several known databases. In this case, the results of Interval ckMeans were compared with the results of other clustering algorithms when applied to an interval database with minimum and maximum temperature of the month for a given year, referring to 37 cities distributed across continents

Manual para calcular en forma comparativa los impuestos a la importación en los países Centroamericanos

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Análise da influência do torque de montagem na resistência de parafusos de fixação

Whereas the assembly torque calculation has great importance on efficiency and life of bolts, the objective of this study was to analyze the combined stresses during assembly, the friction coefficient, compare the rupture torque results with the indicated torques by standards and to present a new torque method without the stress combination (shear stress and normal stresses). For this study were carried eighteen tests with different diameters and materials, this bolts were undergoing five ranges torque until the breaking torque. With the experimental rupture torque values for each test and with the bolt quality certificate was possible to calculate the friction coefficient so compared with the theory. Another comparison was the experimental rupture torque with assembly torque indicated by NBR-8800 and ASME-PCC. The main conclusion are related to combined stress, because for this factor can fail at the assembly time, so for in some cases must use the tensioning method, because in this method won't be present torsional stresses

Modelagem de motor de combustão internae simulação do processo de queima de combustível

The internal combustion engine is a heat engine widely used in the automotive industry. In order to better understand its behavior many models in the literature have been proposed in the last years. The 0-D thermodynamic model is a fairly simple tool but it is very useful to understand the phenomenon of combustion inside the chamber of internal combustion engines. In the first phase of this work, an extensive literature review was made in order to get information about this kind of analysis and, after this, apply them in a model able to calculate the instantaneous temperature and pressure in one zone of the combustion chamber of a diesel engine. Therefore some considerations were made with the aim of increasing the accuracy of the model in predicting the correct behavior of the engine, adding the combined effects of heat transfer, leakage and injection. In the second phase, the goal was to study the internal flow of a three-dimensional model of an internal combustion engine. In order to achieve this goal the software Solidworks was used to create the geometries of an engine and the suite of softwares Ansys was used to create the moving mesh (ICEM CFD and CFX-Pre) and to solve the CFD problem (Ansys CFX code). The model was able to perform the air flow simulation during the four-stroke cycle of an engine: admission, compression, expansion and exhaust. The results obtained from both models were suitable and they open a new range of possibilities for future researches on the field

Implantação do sistema kanban para elementos de fixação em maquinas de movimentação de terra

Always seeking the maximum profit under the reduced production time and lower number of failures, companies are increasingly evolving and going after continuous improvement in order to remain competitive in the market. Thus, increasingly there is investment in the management system Lean manufacturing. Lean system is very important, because through it, the maximum value is added in the final product. Being measured by the efficiency and reducing failures to zero. In the studied company, Lean manufacturing system came into effect through the kanban system for purchasing, control and distribution of bulk material used in the assembly of the final product, which are earth-moving machines. It is very important to check the great change made in the company with the implementation of kanban. All inventory management becomes visual, elements are arranged in an organized manner, with addresses in structures, calculated in special boxes and finally, assemblers have the guarantee of an item supply, with the distribution cars located on their assembly area. This study participates effectively assuring the supply. Avoiding any failure on the lack of material, non-compliance of delivery times to the customer and maintenance of over-stock or obsolete inventory, in which case both cause financial loss to the company