Aplicación de métodos de Correlación Digital de Imágenes y enfoques probabilísticos en el diseño de soluciones presurizadas elaboradas con materiales compuestos

Tesis por compendio de publicaciones[ES]La Ciencia y la Tecnología son herramientas indispensables en la construcción de sociedades modernas. Actualmente se está inmerso en una dinámica que no sólo persigue encontrar soluciones a problemas cotidianos, si no en un esfuerzo que busca el avanzar permanentemente en el conocimiento, para afrontar nuevos retos, buscar nuevas soluciones y mejorar el nivel tecnológico de nuestra sociedad. Es esta filosofía, la que fundamenta la presente Tesis Doctoral. Hace años se hablaba de que en algunos campos se estaban alcanzando los denominados “techos tecnológicos”, pero cuando se estaba cerca de éstos en el campo de la ingeniería se produce una revolución gracias a la aparición de los materiales compuestos. Si bien es cierto que la ingeniería actualmente está dotada de grandes técnicas y herramientas, se tiende a aplicar métodos tradicionales y conocimiento adquirido a las nuevas situaciones. En el ejemplo planteado, esta actitud no siempre arroja buenos resultados, dado el complejo comportamiento y la falta de experiencia en estos nuevos materiales. Este trabajo, en un afán de progresar en la búsqueda de métodos y soluciones más adaptados al contexto actual, relativo a los nuevos materiales, y con el objetivo de encontrar diseños más fiables a la par que económicos, se marca el objetivo inicial de lograr una sinergia con tecnologías propias de la Geomática; concretamente la correlación digital de imágenes. Esta técnica proporcionará un mejor conocimiento del material en su conjunto, a mayores de otras ventajas de índole económica. Inicialmente el trabajo se centra en comparar y aplicar la citada técnica geomática para mejorar la caracterización de materiales compuestos aptos para soluciones presurizadas (recipientes, tuberías, etc). Además, los datos obtenidos permiten caracterizar el comportamiento variable del material, a través de un enfoque de tipo probabilístico. Por otro lado, se adaptan los procesos de cálculo numérico al nuevo enfoque, a la par que se aplican técnicas de análisis sensible en la búsqueda de obtener los parámetros críticos del diseño. También, se avanza en el tratamiento de los resultados; lo que constituye el siguiente escalón evolutivo de la ingeniería. Esto es, pasar de enfoques determinísticos a enfoques probabilísticos, apoyándose en lo que se conoce como Ingeniería Robusta asistida por métodos subrogados para lograr definir procedimientos viables de cara a ser transferidos al ámbito industrial.[EN]Science and Technology are indispensable tools in modern Society. Nowadays we are immersed in a dynamic world of Science and Technology that aims to find solutions to daily problems, to continuously advance knowledge, meet new challenges, find new solutions and to improve Society’s Technological level. This philosophy is the base to the present Ph.D. Years ago, people thought that some Fields were reaching their ‘technological ceilings’ but when this happened in Engineering, there was a new revolution thanks to the creation of composites. Although nowadays, it is true that engineering is supported by great tools and techniques, we still tend to apply traditional methods and adquired knowledge to new situations. In the current work, such traditional methods do not always give reliable results, given the complex behaviour of, and the lack of experience in using these new materials. This work aims to progress by looking for methods and solutions which are better adapted to the current context in Engineering, concerning to composites. The first objective is to achieve a synergy with Geomatic technologies; specifically Digital Image Correlation. This technique will give a better understanding of materials as a whole, as well as other economical advantages. Initially, this work focuses on comparing and applying the cited geomatic technique to improve the characterization of composites appropriate for pressurised solutions (containers, piping, etc). Also the data obtained allows for characterising of the variable behaviour of the material through a probabilistic technique. The numerical calculus processes are adapted to this new technique and at the same time are combined with sensitive analysis techniques to obtain design critical parameters. Also there is an advance in the analysis of the results, that constitutes the next evolutionary step in engineering; that is, to move from a deterministic focus to a probabilistic one. This is supported by what is known as Robust Engineering, assisted by surrogate methods to enable viable procedures to be applied to the industrial environment

Coloración atípica en una hembra de Iberolacerta cyreni en la Sierra de Guadarrama (Madrid)

El trabajo se financió por el proyecto MICIIN-CGL2011-24150/BOSPeer reviewe

Implementación de sistemas CAE en el diseño de mecanismos, dentro del campo de la biomecánica

Memoria ID-0205. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2017-2018

Heterogeneous tempo and mode of evolutionary diversification of compounds in lizard chemical signals

Important part of the multivariate selection shaping social and interspecific interactions among and within animal species emerges from communication. Therefore, understanding the diversification of signals for animal communication is a central endeavor in evolutionary biology. Over the last decade, the rapid development of phylogenetic approaches has promoted a stream of studies investigating evolution of communication signals. However, comparative research has primarily focused on visual and acoustic signals, while the evolution of chemical signals remains largely unstudied. An increasing interest in understanding the evolution of chemical communication has been inspired by the realization that chemical signals underlie some of the major interaction channels in a wide range of organisms. In lizards, in particular, chemosignals play paramount roles in female choice and male–male competition, and during community assembly and speciation. Here, using phylogenetic macro-evolutionary modeling, we show for the very first time that multiple compounds of scents for communication in lizards have diversified following highly different evolutionary speeds and trajectories. Our results suggest that cholesterol, α-tocopherol, and cholesta-5,7-dien-3-ol have been subject to stabilizing selection (Ornstein–Uhlenbeck model), whereas the remaining compounds are better described by Brownian motion modes of evolution. Additionally, the diversification of the individual compounds has accumulated substantial relative disparity over time. Thus, our study reveals that the chemical components of lizard chemosignals have proliferated across different species following compound-specific directions

Relaciones Suelo-Planta en Bosques de Abies pinsapo Boiss. Disponibilidad de Nutrientes y Estatus Nutricional

Relaciones Suelo-Planta en Bosques de Abies pinsapo Boiss. Disponibilidad de Nutrientes y Estatus Nutricional. Se han evaluado las relaciones entre las propiedades del suelo y el estado nutricional de los árboles en pinsapares del Paraje Natural Los Reales de Sierra Bermeja y del Parque Natural Sierra de las Nieves (Málaga-España). Se seleccionaron pinsapares que difieren en cuanto a su estado sucesional (masas agradativas versus maduras) y sustrato litológico (serpentinas versus calizas), en los que se evaluaron variables morfoedáficas de perfiles de suelo, y se analizaron las concentraciones de nutrientes en muestras de suelo, hojarasca y acículas. Los suelos de pinsapares calcáreos en fase agradativa (Yunquera) mostraron las menores concentraciones de macro y micronutrientes totales. Esto se correspondía con contenidos también mínimos de N y P en tejidos foliares, indicando la existencia de un estrés nutricional general, como es habitual en masas forestales en fase de exclusión de tallos (máxima competencia intraespecífica). No obstante, la presencia de relaciones N/P foliares normales implica que dicho estrés nutricional no ha desencadenado desbalances internos entre dichos nutrientes en los árboles. En pinsapares calcícolas maduros (Ronda), la mayor acumulación de materia orgánica en la hojarasca y el suelo superficial se relaciona con un aumento de la disponibilidad de nutrientes en el suelo, y una reducción en el estrés nutricional de los árboles. El pinsapar serpentinícola de Los Reales de Sierra Bermeja mostró niveles anormalmente elevados de N, y de las relaciones N/P, tanto en el suelo como en los tejidos foliares. Estos síntomas son característicos de ecosistemas forestales en una fase temprana del denominado síndrome de saturación de nitrógeno, asociado a disfunciones en el ciclo del N

Proposing a Machine Learning Approach to Analyze and Predict Employment and its Factors

This paper presents an original study with the aim of propose and test a machine learning approach to research about employability and employment. To understand how the graduates get employed, researchers propose to build predictive models using machine learning algorithms, extracting after that the most relevant factors that describe the model and employing further analysis techniques like clustering to get deeper insights. To test the proposal, is presented a case study that involves data from the Spanish Observatory for Employability and Employment (OEEU). Using data from this project (information about 3000 students), has been built predictive models that define how these students get a job after finalizing their degrees. The results obtained in this case study are very promising, and encourage authors to refine the process and validate it in further research

Revisión de la distribución y abundancia de la herpetofauna en las Islas Chafarinas: datos históricos vs. tendencias poblacionales

El estudio fue financiado por contratos del Organismo Autónomo de Parques NacionalesPeer reviewe

A descriptive and quantitative approach regarding erosion and development of landforms on abandoned mine tailings: New insights and environmental implications from SE Spain

The San Cristóbal–Perules mining site in Mazarrón in southeast Spain was subjected to about a hundred years of intense mining activity for lead, silver, and zinc. Metallurgical operations (smelting, calcination, gravity concentration) carried out during the late nineteenth century–early twentieth century induced significant land transformation, and the most conspicuous wastes of this period consist of a chaotic piling of ‘old’ tailing deposits. Later on, during the mid-twentieth century, ‘modern’ tailings resulting from froth flotation were accumulated filling small valleys; these latter valley-fill tailings rose sequentially according to the upstream construction method, progressively raising the level of the dam during the process. Once abandoned, both types of tailing deposits underwent severe erosion, resulting in a mosaic of erosional and sedimentary landforms developed upon (e.g., gully formation) and within them (e.g., piping). We made an inventory and classification of these landforms. Our study shows the geomorphic work to reestablish a new steady state between the tailings deposits and the local erosive conditions. This scenario implies several hazards related to the extremely high heavy metal contents of these tailings and the geomorphic instability of the deposits. We also quantified the tailings tonnage and erosion that occurred at one of the tailings dams (El Roble). As shown by an oblique aerial photograph taken in 1968, this dam had a terraced topography, whereas in 2013 this morphology had evolved into a badland-type relief with deep parallel gullies. By recognizing and surveying specific, remnant points along the benches and outslopes of the older terraced topography, we were able to build up a first digital elevation model (DEM1) reflecting the initial topography. A second DEM, this time showing the present topography, allowed quantification of erosion via Material Loss = DEM1 − DEM2. This yields an erosion rate (1968–2009) of 151.8 Mg (MT) ha− 1 y− 1, which matches well typical values for erosion of mined areas, commonly above 100 Mg (MT) ha− 1 y− 1. Abandoned mine tailing deposits are extremely common in the semiarid scenarios of the SW USA, Australia, Chile, and Peru. Given the similarities of these scenarios with SE Spain, the example from Mazarrón may provide useful new insights regarding the erosion and geomorphic evolution of such tailing deposits. These matters should be addressed in key environmental actions such as mine closure plans and land reclamation projects. A solution may come via restoration of these deposits through landform design involving the building up of stable mature landscapes, which in turn can withstand erosion much more easily.Peer reviewe

Modular total syntheses of thymifodioic/incanic acids

The first total synthesis of the bioactive natural product 2,6-(E,E)-thymifodioic acid, also called incanic acid, and its stereoisomers is described. An unified, iterative and modular strategy was envisioned, achieving the synthesis of the goals products after five reaction steps in an overall yield ranging from 8% to 16%. The key step is a non-expensive easy to perform Horner–Wadsworth–Emmons condensation.Fil: Álvarez Méndez, Sergio J.. Universidad de la Laguna. Departamento de Química Orgánica. Instituto Universitario de Bio-Orgánica "Antonio González"; EspañaFil: Saad, José Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Tonn, Carlos Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Martín, Víctor S.. Universidad de la Laguna. Departamento de Química Orgánica. Instituto Universitario de Bio-Orgánica "Antonio González"; EspañaFil: García, Celina. Universidad de la Laguna. Departamento de Química Orgánica. Instituto Universitario de Bio-Orgánica "Antonio González"; Españ

Step heating thermography supported by machine learning and simulation for internal defect size measurement in additive manufacturing

A methodology based on step-heating thermography for predicting the length dimension of small defects in additive manufacturing from temperature data measured on thermal images is proposed. Regression learners were applied with different configurations to predict the length of the defects. These algorithms were trained using large datasets generated with Finite Element Method simulations. The different predictive methods obtained were optimized using Bayesian inference. Using predictive methods generated and based on intrinsic performance results, knowing the material characteristics, the defect length can be predicted from single temperature data in defect and non-defect zone. Thus, the developed algorithms were implemented in a laboratory set-up carried out on ad-hoc manufactured parts of Nylon and polylactic acid which include induced defects with different sizes and thicknesses. Using the trained algorithm, the deviation of the predicted results for the defect size varied between 13% and 37% for PLA and between 13% and 36% for Nylon.This research has been funded by Ministry of Science and Innovation (Government of Spain) through the research project titled Fusion of nondestructive technologies and numerical simulation methods for the inspection and monitoring of joints in new materials and additive manufacturing processes (FaTIMA) with code RTI2018-099850-B-I00