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Many studies have been carried out to determine the performance of the energy dissipators proposed by different authors, mainly analyzing the hysteretic loops of loading and unloading. Likewise, the authors have sought to have simple, easy to manufacture and economical designs. Based on the above, the analysis of a passive bidirectional dry friction energy dissipator system is presented, whose main characteristic is the implementation of layer elements as structure, besides not requiring bolts or springs for the application of the preload. The study is carried out by means of numerical modeling using the finite element software Abaqus. The energy dissipation analysis is presented by means of hysteresis cycles, for different types of preload and number of stacked layer elements. The device, by means of one of the analyzed configurations, presents the capacity to dissipate 52 J of energy, being an innovative and functional design.

Before planning the large-scale use of nonpathogenic strains of Fusarium oxysporum as biocontrol agents of Fusarium wilt, their behaviour and potential impact on soil ecosystems should be carefully studied as part of risk assessment. The aim of this work was to evaluate the effects of antagonistic F. oxysporum strains, genetically manipulated (T26/6) or not (233/1), on soil microbial biomass and activity. The effects were evaluated, in North-western Italy, in two soils from different sites at Albenga, one natural and the other previously solarized, and in a third soil obtained from a 10-year-old poplar stand (Popolus sp.), near Carignano. There were no detectable effects on ATP, fluorescein diacetate hydrolysis, and biomass P that could be attributed to the introduction of the antagonists. A transient increase of carbon dioxide evolution and biomass C was observed in response to the added inoculum. Although the results showed only some transient alterations, further studies are required to evaluate effects on specific microorganism populations.

En este trabajo se presenta un análisis numérico del acoplamiento entre una catarina motriz y una cadena con elementos de plástico en la transmisión de potencia. El estudio se realiza mediante análisis numérico con software de elementos finitos. El sistema considera los modelos reológicos para la caracterización del material plástico de la cadena. Con base al presente estudio se confirmó la utilidad del modelo de Marlow para casos de cadenas con elementos plásticos. Los resultados muestran las zonas de mayor concentración de esfuerzo debido al contacto entre elementos para la transmisión de potencia y definir la variación de la fuerza de contacto en función de la rotación de la catarina motriz.