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The optimization of civil structures is a technique whose purpose is to efficiently use the materials that make up the structural systems based on previously established restrictions and objectives. The use and development of these techniques has been closely linked to technological advance since, through the use of computer equipment, complex mathematical models can be solved with low cost and time. This article presents OPS Design v2.0, a computer tool that allows obtaining a preliminary optimal distribution of metallic structural profiles in a Non-Braced Frame System (OMF: Ordinary Moment Frame). The optimization model implemented in OPS Design v2.0 seeks to minimize the number of different profiles and the structure's own weight in order to reduce the construction complexity and the weight per linear meter (costs in quantities of material). To evaluate its effectiveness, a case study was developed where it was concluded that the designs produced by the application are more efficient than those obtained by commercial tools, thus reducing the computational expense and time used by designers in iterative processes that are carried out in the initial phases project.
RESUMO
Different types of tuned mass dampers (TMD) have been applied to reduce wind and seismic induces vibrations in buildings. We analyze a pendulum tuned mass damper (PTMD) to reduce vibrations of structures that exhibit elastoplastic behavior subjected to ground motion excitation. Using a simple dynamic model of the primary structure with and without the PTMD and a random process description of the ground acceleration, the performance improvement of the structure is assessed using statistical linearization. The Liapunov equation is used to estimate the mean-square response in the stationary condition of the random process and optimize PTMD parameters. The optimum values of the PTMD frequency and damping ratio are defined as PTMD design values for a specific maximum seismic intensity design criterion. The results show that: (1) The values of the PTMD effectiveness criterion and the optimal design values of the frequency ratio are higher when the damping ratio of the primary structure decreases. (2) The performance of the optimized PTMD is higher when the structure exhibits a linear hysteresis loop (low seismic intensity). (3) The optimized PTMD controls the development of structural plasticity reducing vulnerability. (4) There is a strong dependence of the optimum PTMD parameters on the dynamic soil properties of the building foundation. (5) The PTMD performance improves as its mass increases. The optimum frequency ratio decreases, and the damping ratio increases as the mass of the pendulum increases. The PTMD designed and optimized with the proposed methodology reduces vibrations, controls the development of plasticity, and protects the primary structure, particularly in low and medium-intensity earthquakes.
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Antecedentes. Dentro de las Medicinas Complementarias y Alternativas, las terapias herbales son de las más utilizadas. Es escasa la evidencia sobre el tipo de terapias herbales usadas en Colombia para el tratamiento de trastornos psiquiátricos. Objetivo. Explorar, en un grupo de practicantes de MCA cómo se da el uso de terapias herbales para el tratamiento de los síndromes psiquiátricos más frecuentes (depresión, ansiedad, psicosis, manía). Materiales y métodos. Se efectuó una búsqueda de practicantes de MCA en anuncios de publicidad, internet y referencias de pacientes. De 130 terapeutas ubicados, solo 25 aceptaron participar. A cada terapeuta se le realizó una entrevista en profundidad en la que se exploró el uso de estas terapias con la ayuda de viñetas que ilustraban casos representativos. Resultados. Se identificaron 17 productos herbales diferentes para tratar trastornos psiquiátricos. En los casos correspondientes a psicosis, depresión y ansiedad, se utilizaron 8, 10 y 7 productos diferentes, respectivamente; en el caso de la manía solo se reportó el uso de un producto. Se utilizan combinaciones de terapias herbales y de diferentes tipos de terapias complementarias y alternativas. La mayoría de productos han sido estudiados en investigaciones científicas para evaluar su utilidad terapéutica. Conclusiones. Los psiquiatras deben reconocer que el uso de terapias herbales es una práctica frecuente entre sus pacientes. El desconocimiento sobre su uso puede estar limitando la disponibilidad de nuevas modalidades terapéuticas, afectando la relación médico paciente y poniendo en riesgo a los pacientes ante la posibilidad de interacciones medicamentosas graves.
Background. In Complementary and Alternative Medicine (CAM), herbal therapies are the most frequent modality used. There is scarce evidence of the types of herbal therapies used in Colombia for the treatment of psychiatric disorders. Objective. To explore how herbal therapies are used by traditional medicine practitioners for the treatment of the most frequent psychiatric disorders (depression, anxiety, mania, psychosis). Materials and methods. Traditional medicine practitioners were located searching newspapers, internet, radio commercials, printed advertising and patient's references. Out of 130 practitioners only 25 accepted to participate. An in-depth interview was conducted to explore how these therapies were used, using vignettes that served to illustrate representative clinical syndromes. Results. 17 herbal products have been used by CAM practitioners to treat psychiatric disorders. For treating psychosis, depression and mania 8, 10 and 7 different products were used respectively. Only one product was used to treat mania. Combination of different herbal products and diverse CAM systems is a frequent practice. Most of these products have been scientifically studied for treating health conditions. Conclusions. For psychiatrists an understanding of patient's use of CAM is important in order to improve the therapeutic alliance, to prevent unexpected complications related to herb-drug interactions and to explore potential new treatments.
