Revista Técnica de la Facultad de Ingeniería Universidad del Zulia (REV TEC FAC ING UNIV )

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Publication of the Facultad de Ingeniería, Universidad del Zulia. Mission: Publicar trabajos relacionados con todas las ramas de Ingeniería y las Ciencias Aplicadas.

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Publications in this journal

  • Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 08/2014; 37(2):151-159.
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    ABSTRACT: In the present work, the influence of the degradation during the processing of nanocomposites of poly (lactic acid) (PLA) with montmorillonite and its blends with low density polyethylene as dispersed phase on their morphology and tensile properties was studied. Polymers grafted with maleic anhydride were used as compatibilizer agents. The blends were prepared via melt blending in an internal mixer at 200°C and characterized in terms of solution viscometry of the PLA phase, infrared spectroscopy, and scanning and transmission electron microscopy. Results showed that the processing of PLA produced thermo-mechanical degradation in the polymer and a significant decrease in the viscosity molecular weight of the PLA phase in the different composites. The large sizes of the dispersed phases in the unfilled PLA blends and the low values of the tensile properties could be attributed to the thermo-mechanical degradation of the PLA matrix during its processing. The blends with PLA as matrix and PEBD as dispersed phase exhibited the highest elongation at break. Lower values in tensile properties were obtained in the blend with montmorillonite than those obtained for the blend without the layered clay due probably to the degradation during the processing and also to their morphology.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 08/2014; Vol. 37(2):135-143.
  • Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 08/2014; 37(2):167-175.
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    ABSTRACT: It can be observed that the number of vehicles, accidents and congestion increase proportionally with the development of a city. A vehicular traffic system behaves like a system of discrete events, and due to variations that affect the level of congestion, modeling and controlling this system becomes a complex task. Petri Nets are one of the most powerful tools for modeling graphically and mathematically. Some systems are characterized by little information, inaccurate data and / or permanent changes with regard to the model of the system, which makes modeling and control difficult. This has led to modeling techniques that apply adaptation techniques and human knowledge representation through bio-inspired computing systems such as Neural Networks and Fuzzy Logic. These techniques will be harnessed in this work in terms of an approximated model for learning in a discrete concurrent system by using Fuzzy Petri Nets to represent knowledge through the application of inference and adaptive rules in a chaotic environment, like it can be found in a traffic system.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 06/2014; 16(1):185.
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    ABSTRACT: A functional is defined on a subset of L 2 (Ω), with Ω bounded and so that the divergence theorem is valid. It shows that t his functional is differentiable, coercive and weakly lower semi- continuous bound, and therefore has critical points which coincide with the solutions of the stationary Boltzmann equation solutions under a condition of Poisson.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 01/2013; 3(3).
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    ABSTRACT: A bi-dimensional numerical model of the connections test at elevated temperatures was developed by means of the finite element computer program “SuperTempcalc”. Essential references of the recommended criteria were taken from the eurocodes EN 1991-1-2 and EN 1994-1-2. Consequently, the thermal conductivity and the specific heat of the steel and the concrete are adopted as dependent values of the temperature. The density of each material is defined as a constant value. The exposed parts of the specimen cross-section are considered under the action of the standard fire ISO 834-1, while the non-exposed parts are considered at room temperature. The results of the push-out tests at elevated temperatures developed at CTICM, France, were used to calibrate the models against the experimental data. In general, a relatively simple model was obtained. It also has the advantage of being very efficient and quick to use. In terms of obtaining reliable temperatures for a structural analysis the model is more than adequate. The sensitivity of the calibrated model to variation in connector diameter and height is assessed, taking into account the defined scope of the formulations of EN 1991-1-2 and EN 1994-1-2. Also, different alternatives on the level at which should be considered the concrete temperatures are analyzed in order to evaluate the simplified method of EN 1994 1-2.
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 01/2013; 36(3):210.
  • Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 01/2013; 36(3).
  • Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 01/2013; 36(1):3-12.
  • Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 12/2012; 35(3):311-320.
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    ABSTRACT: This research work deals with the development of a survey model designed to collect information about functional behavior of the operative personnel working for an aircraft maintenance company devoted to service general aviation (small aircraft of less than 12,500 pounds). The reliability model was based on different factors affecting the workers performance during the productive activity of the company. Influencing factors considered were: training, development, ergonomics, ownership, communication and human needs, as proposed by Abraham Maslow. The model used facilitates a better understanding of the causes that stimulate workers to do a better work to the benefit of their organization. Once the model was carefully validated and the field data was acquired at the company facilities, the values obtained with the Maslow model were analyzed by means of graphical representation. Results were used as a starting point to generate human reliability strategies in order to improve processes and maintenance operations in the aviation maintenance company under study
    Revista Técnica de la Facultad de Ingeniería Universidad del Zulia 06/2012; 35(3):270-278.