37 research outputs found

    REHABEND 2016

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    Producción CientíficaEl objetivo principal de este trabajo es el perfeccionamiento del ensayo no destructivo de velocidad de propagación de ondas ultrasónicas sobre madera aserrada de coníferas de gran escuadría y uso estructural (MEG), y la interpretación de los resultados obtenidos. Para ello se han escogido dos especies de madera ampliamente utilizadas (Pinus sylvestris L. y Pinus radiata D. Don) y un aparato de ondas sónicas Fakopp Microsecondtimer©, por sus cualidades para emplearlo sobre estructuras construidas con acceso limitado. Por medio de la realización de ensayos en laboratorio sobre un abanico de ángulos conocidos, se ha estudiado la influencia que tiene el ángulo entre la dirección de la fibra y la de las ondas ultrasónicas al realizar ensayos indirectos; en la práctica los únicos posibles en la mayoría de estructuras en servicio. Se ha optimizado el postproceso analítico de resultados para la generación de un modelo de ajuste (ecuación general) en función del ángulo, obtenido por la regresión de datos reales medidos en laboratorio para las especies y el equipo empleado. Se determinan también los ángulos de aplicación más homogéneos y fiables para la realización de este tipo de ensayo indirecto en obra

    Morphology and Material Composition of the Mouthparts of Stromatium unicolor Olivier 1795 (Coleoptera: Cerambycidae) for Bionic Application

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    The novelty of this study is the deep analysis of the morphologic, geometric and mechanical performance of longhorn beetle larvae mouthparts. Furthermore, a metal nano identification of jaw reinforced parts was made. Background and Objectives: Analysis of insect mechanical properties has shown an important application in the develop of bionic technologies such as new materials, industrial machines and structural concepts. This study aims to determine the mechanical and geometric properties of longhorn beetle (Stromatium unicolor Olivier 1795) larvae mouthparts to improve the development of innovative cutting tools. In addition, this study obtains a nano identification of metals in the cuticle of the mouthparts, which will enable the development of new nontoxic and sustainable preservation agents against xylophagous insects based on nanoparticles. Materials and Methods: five third-larval-stage samples of Stromatium unicolor were used to study its mandible morphologic, geometric and mechanical properties. To this end, mouthparts were analyzed by several microscopic techniques using a scanning electron microscope, a stereomicroscope and an optical microscope. Composition analysis was performed using with two Analytical-Inca X-ray detectors, dispersive energy spectroscopy and dispersive wavelength spectroscopy. Results: The main geometric parameters of the insect jaw are the edge angle (β = 77.3°), maximum path depth of the insect (120 μm), length (800 µm) and mouthpart movement, which were identified and measured. The chemical analysis results of the jaw tissues shows the presence of zinc and manganese. Conclusions: The geometry and angles of the mouthparts can be applied in the fabrication of bionic self-sharpening cutting tools. Molecular compounds that form the reinforcing elements in the jaws can be used to develop wood preservatives based on nanometals and metal absorption and metabolism inhibitor

    Diferencias biopsicosociales en el trastorno por consumo de sustancias entre el hombre y la mujer y consideraciones sobre su abordaje terapéutico

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    Introducción. Con la finalidad de investigar las diferencias vinculadas al sexo en el abuso de drogas, intentar com-prender los fundamentos biológicos y psicosociales subyacentes, y analizar la pertinencia de diseñar intervenciones diferenciales, se ha realizado un rastreo de la información científica publicada, especialmente en humanos, pero en algunos casos también en animales. Objetivos. Partiendo de las diferencias anatómicas y neuroquímicas del cerebro, de las diferentes destrezas y de la posible importancia de los factores evolutivos, se revisan las diferencias biopsicosociales, ligadas al sexo, en relación al abuso de sustancias, así como el sesgo en las enfermedades neuropsiquiátricas, en bastantes casos concurrentes. Se revisa asimismo el papel de las hormonas sexuales y el peso de los roles de género en la adicción. Además, se analizan las características diferenciales del tratamiento de las conductas adictivas según el sexo. Desarrollo y conclusiones. Los resultados señalan peculiaridades específicas en el proceso de la adicción según el sexo, causadas por las diferencias biológicas del cerebro y las diferentes hormonas sexuales circulantes. Estas dife-rencias se manifiestan tanto en los efectos de las drogas en el circuito de recompensa como en su metabolismo, y en el grado de severidad de las diferentes fases del proceso adictivo: adquisición, escalada de consumo, abstinencia y recaída. También se perciben diferencias significativas en las enfermedades neuropsiquiátricas asociadas. Todo ello está modulado por las particularidades de género impuestas socialmente. Finalmente, se valora la necesidad de abordajes terapéuticos específicos en función del sexo, que cobran aún más importancia ante la presencia de problemas psicológicos o psiquiátricos concomitantes.Introduction. A search of scientific papers has been carried out in order to investigate sexual differences in drug abuse, and to underlying biological and psychosocial explanatory causes of these differences. Goals. Based on the anatomical and neurochemical differences of the male and female brain, the difference in skills and the possible importance of evolutionary factors, the reasons for the differential characteristics of addictions in men and women, as well as the sexual bias in the concurrent neuropsychiatric disorders are reviewed. The impor-tance of sex hormones in these differences is also reviewed, as well as the influence of psychosocial conditioning factors associated with gender in addiction. Finally, the main features that differentiate the treatment of drug abuse in men and women are reviewed. Development and conclusions. The results obtained indicate that there is a close link between the differential bio-logical characteristics of the male and female brain and sex hormones, which explain the specific characteristics of drug abuse according to sex. These differences exist both in the reward circuit, in metabolism and in the different phases of the addictive process: acquisition, escalation of consumption, abstinence and relapse, as well as in the associated neuropsychiatric disorders, all them modulated by psychosocial gender particularities. Finally, the need for separate sex treatments, especially indicated in the presence of coexisting psychological or psychiatric disorders, is assessed

    Internal reinforcement of laminated duo beams of low-grade timber with GFRP sheets

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    The purpose of this work is to study the flexural behaviour of Populus euroamericana I-214 low-grade glulam timber beams, internally reinforced with Glass Fibre Reinforced Polymer (GFRP). To this end, 30 unreinforced beams and 60 reinforced beams, with two ratios of GRFP reinforcement, were produced and tested. Results show an improvement in the flexural behaviour of reinforced beams, with noticeable increases in stiffness (MOE) and ultimate moment capacity (MOR). By using relatively low reinforcement ratios (1.07%, 1.6%) in the tension zone, we have measured an average improvement of 12.1% and 14.7% in stiffness, and an increase up to 23% in moment capacity. GFRP reinforced seems to reduce the influence of timber heterogeneity and singularities (knots, cracks . . .), which translates into less scattered results and better characteristic values.Ministerio de Ciencia e Innovación (project BIA2012-31233)Junta de Castilla y León (project VA051A10-2

    Internal GFRP Reinforcement of Low-Grade Maritime Pine Duo Timber Beams

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    This paper presented an experimental structural-scale test campaign used to analyze the flexural behavior of low-grade maritime pine (Pinus pinaster Ait.) duo timber beams reinforced with an internal glass fiber-reinforced polymer (GFRP) sheet. For this purpose, thirty (30) unreinforced duo beams and thirty (30) duo beams internally reinforced with a unidirectional GFRP sheet with an areal mass of 1200 g/m2 were produced and tested. The addition of a low GFRP reinforcement ratio (1.07%) in the tension zone of the duo beams provided an average improvement of 8.37% in bending stiffness (EI) and an increase of up to 18.45% in ultimate moment capacity. In addition to this improved bending behavior, the internal GFRP reinforcements seemed to decrease the influence of wood singularities and wood heterogeneity on mechanical properties, which allowed for better characteristic values to be reached and for the achievement of results with less variability.Ministerio de Ciencia e Innovación (grant BIA2012-31233)Junta de Castilla y León (grant VA051A10-2

    Design and validation of a scalable, reconfigurable and low-cost structural health monitoring system

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    Producción CientíficaThis paper presents the design, development and testing of a low-cost Structural Health Monitoring (SHM) system based on MEMS (Micro Electro-Mechanical Systems) triaxial accelerometers. A new control system composed by a myRIO platform, managed by specific LabVIEW software, has been developed. The LabVIEW software also computes the frequency response functions for the subsequent modal analysis. The proposed SHM system was validated by comparing the data measured by this set-up with a conventional SHM system based on piezoelectric accelerometers. After carrying out some validation tests, a high correlation can be appreciated in the behavior of both systems, being possible to conclude that the proposed system is sufficiently accurate and sensitive for operative purposes, apart from being significantly more affordable than the traditional one.Junta de Castilla y León y Fondo Europeo de Desarrollo Regional (FEDER) - (grant VA095P17 and VA228P20

    Assessment of machine learning algorithm-based grading of Populus x euramericana I-214 structural sawn timber

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    The efficiency of visual grading standards applied to structural timber is often inappropriate, and timber properties are either under or over-graded. Although not included in the current UNE 56544 visual grading standard, machine learning algorithms represent a promising alternative to grade structural timber. The general aim of this research was to compare the performance of machine learning algorithms based on visual defects, non-destructive techniques and sawing systems (“cut type”) with UNE 56544:1997 visual grading in order to predict the qualifying efficiency of Populus x euramericana I-214 structural timber. Visual evaluation, ultrasound and vibrational non-destructive testing, and sawing systems register (radial, tangential and mixed) were applied to characterize 945 beams. In addition, in order to retrieve actual physical-mechanical values, density and static bending destructive testing (EN-408:2011 + A1:2012) was also carried out. Several machine learning algorithms were then used to grade the beams, and their predictive accuracy was compared with that of visual grading. To do so, three scenarios were considered: a first scenario in which only visual variables were used; a second scenario in which “cut type” variables were also included; and a third scenario in which additional non-destructive variables were considered. Results showed a poor level of performance of UNE 56544:1997, with an apparent mismatch between the strength values assigned for each visual grade (established by the EN 338 standard) and the actual values. On the opposite, all algorithms performed better than visual grading and may thus be deemed as promising timber strength grading tools.Junta de Castilla y León (project VA047A08

    Efectos de las radiaciones electromagnéticas de la telefonía móvil sobre los insectos

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    Se presenta una revisión de estudios de laboratorio realizados exponiendo insectos a radiaciones electromagnéticas en el rango de las microondas, similares a las utilizadas por los sistemas de telefonía que se utilizan actualmente, y a campos electromagnéticos de baja frecuencia. Las microondas pulsadas y moduladas de la telefonía son un reciente contaminante ubicuo, cuyas consecuencias todavía no han podido ser evaluadas convenientemente. Los estudios realizados indican efectos sobre este grupo de fauna, con previsibles consecuencias sobre los ecosistemas. Se recomienda la realización de seguimientos y estudios en las proximidades de las estaciones base de telefonía, donde existen los niveles más elevados de contaminación electromagnética y se exponen algunas características técnicas que pueden ayudar a identificar las áreas más afectadas por la radiación

    ¿Pueden afectar las microondas pulsadas emitidas por las antenas de telefonía a los árboles y otros vegetales?

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    El despliegue de la telefonía sin cable, acontecido durante la última década en todo el mundo, ha elevado la contaminación electromagnética en el rango de las radiofrecuencias en varios órdenes de magnitud, sobre todo en los núcleos habitados. No se han previsto los efectos sobre los seres vivos especialmente sobre los que, por su inmovilidad o sedentarismo, o por su proximidad a las instalaciones, padecen una irradiación crónica de niveles elevados, que según algunos expertos en bioelectromagnetismo tienen efectos acumulativos. El bioelectromagnetismo es una disciplina científica minoritaria que ha despertado interés y experimentado un gran auge recientemente. Una gran mayoría de investigadores independientes reconocen los efectos no térmicos de estas ondas sobre los seres vivos, que todavía no están contemplados en la legislación española. Con niveles de densidad de potencia miles de millones de veces más bajos existe suficiente cobertura para que la telefonía móvil funcione

    Potential Effects of Anthropogenic Radiofrequency Radiation on Cetaceans

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    Cetaceans are cast to shore for a large number of reasons, although sometimes it is not clear why. This paper reviews the types and causes of cetacean strandings, focusing on mass strandings that lack a direct scientific explanation. Failure of cetacean orientation due to radiofrequency radiation and alterations in the Earth’s magnetic field produced during solar storms stand out among the proposed causes. This paper proposes the possibility that anthropogenic radiofrequency radiation from military and meteorological radars may also cause these strandings in areas where powerful radars exist. A search of accessible databases of military and meteorological radars in the world was carried out. Research articles on mass live strandings of cetaceans were reviewed to find temporal or spatial patterns in the stranding concentrations along the coast. The data showed certain patterns of spatial and temporal evidence in the stranding concentrations along the coast after radar setup and provided a detailed description of how radars may interfere with cetacean echolocation from a physiological standpoint. Plausible mechanisms, such as interference with echolocation systems or pulse communication systems, are proposed. This work is theoretical, but it leads to a hypothesis that could be empirically tested. Further in-depth studies should be carried out to confirm or reject the proposed hypothesis
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