Comportamiento termomecánico de pilotes prefabricados

This thesis follows the development of the PITERM project (Thermo-mechanical characterization and new design techniques of geothermal piles) within the Spanish INNPACTO 2011 program, a public-private cooperation funded by our Ministry of Science and Innovation. This project was the first to aim at a fully integrated analysis of the combined effect of mechanical and thermal actions upon a newly designed precast pile, thermally activated and fully instrumented. The project started in September 2011 and lasted until December 2013. The overall goal of this project was to analyse the behaviour of thermo-active foundations in order to further develop-relevant design methodologies for these elements, to be validated by experimental data By means of this combined analytic-experimental effort, we aim to validate the idea that foundations, designed appropriately, are able to cope with the thermal and mechanical stresses to which they ought to be subjected throughout its lifespan. More specifically, the project has studied the thermomechanical behaviour of a prefabricated pile driven in Valencia, prepared to work as thermo-active element and properly instrumented. With the registration and interpretation of data from the instrumented it was possible to evaluate its behaviour under mechanical and thermal stresses similar to those that would exist in a real working scenario. The results of this Thesis allow to understand and characterize the mechanical behaviour of geo-active piles and their response under different types of thermal cycling stresses under realistic conditions, contributing to the extension and dissemination of the use of this type of geo-structural elements, and, in the long run, aiming to increase our ability to harvest renewable heat out of the subsurface of our cities.La presente tesis doctoral es consecuencia del desarrollo del proyecto PITERM (Caracterización termo-mecánica y nuevas técnicas de diseño de pilotes termo-activos), dentro del subprograma INNPACTO 2011, del programa nacional de cooperación público-privada del Ministerio de Ciencia e Innovación. Este proyecto ha sido el primero que ha integrado en el análisis el efecto combinado de las acciones mecánicas, geotécnicas y térmicas en el comportamiento de un pilote prefabricado hincado, activado térmicamente y completamente instrumentado. El proyecto se inició en septiembre de 2011 y se prolongó hasta diciembre de 2013. El proyecto se orienta hacia el análisis del comportamiento de las cimentaciones termo-activas, el desarrollo de metodologías de diseño de estos elementos, en particular de los pilotes termoactivos, y su validación mediante datos experimentales. El objetivo de este trabajo es validar, mediante una aproximación analítico-experimental, que los elementos objeto de estudio son capaces de hacer frente a las solicitaciones térmicas y mecánicas a las que se verá sometida a lo largo de su vida útil. Más concretamente, en el proyecto se ha estudiado el comportamiento termo-mecánico de un pilote prefabricado y posteriormente hincado en Valencia, preparado para funcionar como elemento termoactivo, debidamente instrumentado. Con el registro e interpretación de los datos de las variables instrumentadas se ha evaluado el comportamiento del pilote sometido a solicitaciones mecánicas y térmicas semejantes a las que lo estaría en una obra real de edificación con aprovechamiento geotérmico. Los resultados de esta tesis permiten entender y caracterizar el comportamiento mecánico de los pilotes y su respuesta ante diferentes solicitaciones térmicas en condiciones similares a las que tendrían en un edificio real. En este sentido, pretende ser una contribución a la extensión y popularización del uso de estos elementos en aras a aumentar nuestra capacidad de captar energía renovable del subsuelo de nuestras ciudades.El present TESIS doctoral es conseqüència del desenrola del projecte PITERM (Caracterització termo-mecànic i noves tècniques de disseny de pilotes termo-actius), dins del SUBPROGRAMA INNPACTO 2011, del programa nacional de cooperació publica-privada del Ministeri de Ciència i Innovació. Este projecte ha segut el primer que ha integrat en la anàlisis l'efecte combinat de les accions mecàniques, geotécnicas i tèrmiques en el comportament d'un pilote prefabricat estacionat, activat tèrmicament i completament instrumentat. El projecte s'inicià en setembre de 2011 i se prolongà fins desembre de 2013. El projecte s'orienta cap al anàlisis del comportament de les fonamentacions termo-actives, el desenrola de metodologies de disseny d'estos elements, en particular dels pilotes termoactivos, i la seua validació mediant senyes experimentals. L'objectiu d'este treball es validar, mediant una aproximació analítica-experimental, que els elements objecte d'estudi son capaços de fer front a les sol¿licitacions tèrmiques i mecàniques a les que se vorà somes a lo llars de la seua vida útil. Mes concretament, en el projecte s'ha estudiat el comportament termo-mecànic d'un pilote prefabricat i posteriorment estacionat en Valencia, preparat per a funcionar com element termoactivo, degudament instrumentat. En el registre i interpretació de les senyes de les variables instrumentades s'ha valorat el comportament del pilote somes a sol¿licitacions mecàniques i tèrmiques semblants a les que ho estaria en una obra real d'edificació en aprofitament geotèrmic. Els resultats d'esta tesis permeten entendre i caracteritzar el comportament mecànic dels pilotes i la seua resposta davant diferents sol¿licitacions tèrmiques en condicions similars a les que tindrien en un edifici real. En este sentit, pretén ser una contribució a l'extensió i popularització de l'ús d'estos elements en ares a augmentar nostra capacitat de captar energia renovellable del subsòl de nostres ciutats.Groot Viana, MD. (2017). Comportamiento termomecánico de pilotes prefabricados [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/89097TESI

Bidirectional Modulation of Thermal and Chemical Sensitivity of TRPM8 Channels by the Initial Region of the N-terminal Domain

TRPM8, a nonselective cation channel activated by cold, voltage, and cooling compounds such as menthol, is the principal molecular detector of cold temperatures in primary sensory neurons of the somatosensory system. The N-terminal domain of TRPM8 consists of 693 amino acids, but little is known about its contribution to channel function. Here, we identified two distinct regions within the initial N terminus of TRPM8 that contribute differentially to channel activity and proper folding and assembly. Deletion or substitution of the first 40 residues yielded channels with augmented responses to cold and menthol. The thermal threshold of activation of these mutants was shifted 2 °C to higher temperatures, and the menthol dose-response curve was displaced to lower concentrations. Site-directed mutagenesis screening revealed that single point mutations at positions Ser-26 or Ser-27 by proline caused a comparable increase in the responses to cold and menthol. Electrophysiological analysis of the S27P mutant revealed that the enhanced sensitivity to agonists is related to a leftward shift in the voltage dependence of activation, increasing the probability of channel openings at physiological membrane potentials. In addition, we found that the region encompassing positions 40–60 is a key element in the proper folding and assembly of TRPM8. Different deletions and mutations within this region rendered channels with an impaired function that are retained within the endoplasmic reticulum. Our results suggest a critical contribution of the initial region of the N-terminal domain of TRPM8 to thermal and chemical sensitivity and the proper biogenesis of this polymodal ion channel

First large-scale study reveals important losses of managed honey bee and stingless bee colonies in Latin America

International audienceOver the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees ( Apis mellifera ), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016–2017 and 2017–2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region. Summer losses were higher than winter losses in stingless bees (30.9% and 22.2%, respectively) but not in honey bees (18.8% and 20.6%, respectively). Colony loss increased with operation size during the summer in both honey bees and stingless bees and decreased with operation size during the winter in stingless bees. Furthermore, losses differed significantly between countries and across years for both beekeepers and meliponiculturists. Overall, winter losses of honey bee colonies in Latin America (20.6%) position this region between Europe (12.5%) and the United States (40.4%). These results highlight the magnitude of bee colony losses occurring in the region and suggest difficulties in maintaining overall colony health and economic survival for beekeepers and meliponiculturists