Effect of water saturation on strength and deformability of building calcarenite stones: Correlations with their physical properties

Stone construction elements are frequently in moist environments or in direct contact with water. Design and test standards have traditionally ignored the water impact on rock materials. However, several studies have shown that moisture can cause drastic strength reductions and deformability increase in some sedimentary rocks. For that reason, the main objectives of this work are: a) to quantify and understand the influence of water saturation on strength and deformability of four porous calcarenite building stones widely used in SE Spain; b) to establish correlations between physical and mechanical properties of these rock materials in dry and saturated states and c) to compare the results with previous findings. The results showed a very significant reduction of mechanical properties such as unconfined compressive strength, Young’s modulus and point load strength index when these stones undergo saturated. In addition, significant correlations between physical properties (density, porosity, P wave velocity and dynamic elastic parameters) and the mentioned mechanical properties were established in dry and saturated conditions. Additionally, relationships among the mechanical properties of stones in both states are also proposed.This work was supported by the Vicerrectorado de Investigación y Transferencia del Conocimiento of the University of Alicante through Predoctoral grant FPUUA53-2018 and the projects UAUSTI18-21 and UAEEBB2018-09

Assessing water-induced changes in tensile behaviour of porous limestones by means of uniaxial direct-pull test and indirect methods

Understanding the uniaxial tensile behaviour of rocks and its water-induced variation are key issues for designing effective mining and civil engineering structures and for assessing numerous geotechnical hazards. However, these aspects remain poorly analysed because conducting uniaxial direct pull tests is a difficult and time-consuming laboratory task that requires the use of sophisticated equipment and complex rock sample preparation and processing. This work attempts to expand knowledge by determining several tensile properties of three porous limestone lithotypes under dry and water-saturated conditions through two different approaches: by conducting direct tensile tests and by means of indirect methods (i.e. Brazilian and point load tests). The results revealed that water saturation generated important reductions in their uniaxial tensile strength (UTS), tensile elastic modulus (Et), Brazilian tensile strength (BTS) and point load strength index (Is(50)). In addition, their petrological characteristics and mineralogical composition are used to discuss the main causes of the observed tensile softening. Furthermore, highly accurate correlation functions were established between the direct tensile strength parameters (UTS and Et) and the indirect ones (BTS and Is(50)) for the whole set of tested rocks. The proposed relationships are a novel and useful contribution to geomechanics because they enable the estimation of pure tensile parameters using alternative, cheap, rapid and versatile tests.This work was partially supported by the Vicerrectorado de Investigación y Transferencia del Conocimiento of the University of Alicante through the projects UAEEBB2018-09, UAUSTI18-21, UAUSTI20-20 and UAUSTI19-25

Advances in the understanding of the role of degree of saturation and water distribution in mechanical behaviour of calcarenites using magnetic resonance imaging technique

A thorough knowledge of the variations of mechanical properties of rock materials with their water content is essential for evaluating the structural behaviour and durability of stone constructions exposed to different moist environments during their lifetime and for solving a broad range of rock mechanics issues. In this study, the effect of degree of saturation (Sr) and water distribution inside pore network on mechanical parameters such as Uniaxial Compressive Strength, Young’s modulus, Brazilian Tensile Strength and Point Load Strength Index was assessed for three varieties of a calcarenite. To this aim, the corresponding mechanical tests and Magnetic Resonance Imaging technique were applied during different time intervals in specimens prepared with different Sr values through two different wetting procedures: (1) the oven drying of saturated samples and (2) the water immersion of dry samples. In general terms, the results showed that for small Sr values (≤50%) the specimens wetted using the drying process exhibit greater mechanical properties reductions than those moistened through the immersion process while for higher Sr values (>50%) the decreases are quite similar for both wetting procedures. As a consequence, different negative exponential functions can be used to describe the relationship between water content and mechanical parameters of calcarenites depending on the wetting procedure used. These results can be explained by the different water distributions inside the partial-saturated specimens and the main involved water-weakening mechanisms. Additionally, slightly different correlation functions between the mechanical parameters were established for specimens moistened using each of the wetting processes.This research was supported by the Vice-rector of Research and Knowledge Transfer of the University of Alicante through predoctoral grant FPUUA53-2018 and projects UAUSTI18-21, UAUSTI19-25, UAUSTI20-20, UAEEBB2018-09 and GRE18-15 and by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project TEC2017-85244-C2-1-P

Impact of water on peak and residual shear strength parameters and triaxial deformability of high-porosity building calcarenite stones: Interconnection with their physical and petrological characteristics

Several studies have found that water can cause substantial reductions of mechanical properties of building stones such as unconfined compressive strength, tangent Young’s modulus or tensile strength. However, the influence of water content on shear strength parameters, triaxial compressive strength and modulus of elasticity under different confining pressures has been scarcely examined. For this reason, the present paper assesses the impact of water on peak and residual compressive strength and tangent Young’s modulus of three porous building geomaterials widely used in civil and architectural constructions under different confining pressure through triaxial compressive tests. Furthermore, the corresponding peak and residual shear strength parameters computed from Mohr-Coulomb (c and ϕ) and from Hoek-Brown (σci and mi) failure criteria are obtained under dry and saturated conditions. Complementary physical and petrological analyses are performed in order to understand the main causes of the effect of water observed in these rock materials. The results indicate that water causes significant reductions of peak and residual compressive strength and tangent Young’s modulus in the tested porous building stones for all the different applied confining pressures. Additionally, important changes of peak and residual shear strength parameters (c, ϕ, σci and mi) are exhibited by the studied stones when become saturated. This could be related to physicochemical changes such as the hydrolysis of quartz and silicates in crack tip region inducing subcritical crack growth (stress corrosion), the decrease of the cement quality and the deterioration of the intergranular bonds due to the dispersion or dissolution of some minerals (calcite or chlorite) and the formation of microcracks caused by the swelling of the clay minerals present in these materials when they come into contact with water.This research was supported by the Vice-rector of Research and Knowledge Transfer of the University of Alicante through predoctoral grant FPUUA53-2018 and projects UAUSTI18-21, UAUSTI19-25, UAEEBB2018-09 and GRE18-15 and by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project TEC2017- 85244-C2-1-P

Análisis de la influencia aerodinámica de la forma estructural de los camiones mediante técnicas CFD

[ES] El presente documento, recoge el análisis de la forma aerodinámica de un camión con semirremolque. El análisis está basado en la cabina de un Mercedes – Benz Actros y un semirremolque de tres ejes, los cuáles han sido adaptados para su estudio. La principal motivación para el desarrollo de este trabajo es la constante búsqueda de la reducción del consumo de carburantes en el mundo de la automoción, y la restricción cada vez mayor de los agentes contaminantes emitidos a la atmósfera. Por ello, una vez concluido el estudio aerodinámico del camión tomado como modelo, se realizará una propuesta de mejora aerodinámica, buscando la eficiencia aerodinámica para minimizar el consumo y maximizar el rendimiento del camión. Con los resultados obtenidos se realizará la comparación entre los dos diseños, calculando la potencia demandada al motor en cada caso.[CA] El present document, recull l'anàlisi de la forma aerodinàmica d'un camió amb semiremolc. L'anàlisi està basada en la cabina d'un Mercedes – Benz Actros i un semiremolc de tres eixos, els quins han estat adaptats per al seu estudi. La principal motivació per al desenvolupament d'aquest treball és la constant cerca de la reducció del consum de carburants al món de l'automoció, i la restricció cada vegada major dels agents contaminants emesos a l'atmosfera. Per això, una vegada conclòs l'estudi aerodinàmic del camió pres com a model, es realitzarà una proposta de millora aerodinàmica, buscant l'eficiència aerodinàmica per minimitzar el consum i maximitzar el rendiment del camió. Amb els resultats obtinguts es realitzarà la comparació entre els dos dissenys, calculant la potència demandada al motor en cada cas.[EN] The following document, resumes the analysis of the aerodynamic form of a truck with semitrailer. The analysis is based on a Mercedes – Benz Actros truck and a semi-trailer equipped with three axles, which have been adapt as needed to perform the analysis. The main reason to develop this document is the continue search for improving fuel consumption of petrol on automotive industry, and increasing restrictions about contaminant agents drop to the atmosphere. Due to this, once the study of the model truck has been concluded, a proposal for improvements will be made, searching for the aerodynamic efficiency to minimize the consumption and maximize the performance of the truck. With the results, a comparison between designs will be made, comparing the power demand to each engine of the truck on each case.Tomás Tatay, Á. (2017). Análisis de la influencia aerodinámica de la forma estructural de los camiones mediante técnicas CFD. http://hdl.handle.net/10251/87960.TFG

Tumor Microenvironment Heterogeneity: A Review of the Biology Masterpiece, Evaluation Systems, and Therapeutic Implications

A tumor can be considered as a highly heterogeneous functional tissue, connected and dependent on the microenvironment, which sends and receives signals to and from the tumor tissue itself. Tumor cells alter the mechanical properties of the microenvironment in order to create favorable conditions for their proliferation. Stromal cells and non‐cellular elements of the extracellular matrix (ECM), including the host immune system, the fibrous scaffolding, the fundamental substance, and blood vascularization can determine tumoral cell morphologies, functions, aggressiveness, and response to treatment, as well as an accurate assessment of prognosis of the patients. Robust morphometric digital pathology techniques that are able to standardize measurements and analyse whole sets of immunohistochemical images are called for to identify, describe, and quantify the elements of the ECM. The computer‐automated segmentation algorithms are therefore required to increase the knowledge on the tumor microenvironment heterogeneity and to provide new therapeutic targets

El desafío de recibirse

El presente trabajo tiene como objetivo, conocer las modificaciones producidas a lo largo del cursado, en los motivos de elección de carrera y su relación con eventos emocionalmente significativos, en dieciocho estudiantes avanzados de la Licenciatura en Psicología. Para ello, se realizó una investigación cualitativa con un diseño fenomenológico de alcance descriptivo. Se utilizó como instrumento de recolección la entrevista semi-estructurada, y los datos fueron analizados bajo la modalidad de análisis categorial de tipo inductivo. Los resultados de la investigación señalan que los motivos de elección, al inicio de la carrera, tienen una índole predominantemente emocional y de baja especificidad. En el Quinto Año, adquieren un grado de elaboración y especificidad mayor, y rescatan el aprendizaje de los años anteriores. Finalmente, luego de egresar, aparecen motivos que reconocen la repercusión social del quehacer del psicólogo. Los eventos emocionalmente significativos se dan en relación a tres grandes aspectos: plan de estudios, relaciones interpersonales universitarias, y ámbito extracurricular. Presentan, a su vez, una relación circular o de retroalimentación con los motivos de elección que adopta tres formas: actualización y, en menor medida, enriquecimiento o confirmación de los motivos.The purpose of this paper is to know the modifications of the reasons why eighteen advanced students choose to study Psychology throughout their career and what is the relation between those changes and other emotionally significant events. To that end, a qualitative descriptive investigation has been conducted using a phenomenological design. The tool employed for data collection was a semi structured interview, and the information obtained from it was interpreted through an inductive categorical data analysis procedure. The results thrown by the investigation show that motives for undertaking this degree are, in the beginning, predominantly emotional and very poorly specified. In the last year of the career, those motives gain more complexity and specificity as they recover the experience from previous years. Finally, a year and a half later, these motives are once again altered as these future psychologists start to recognise the social effects their professional practices will have. The emotionally significant events relate to three essential aspects: the curriculum, the interpersonal relations inside the University and those that happen outside the academic field. Simultaneously, motives and events together become involved in a feedback loop that can assume three forms: update and, less commonly, enrichment and confirmation.Fil: Ampuero, Álvaro Tomá

Utilización de medidas de fluorescencia de la clorofila para monitorizar el estado nutricional y estimar el potencial enológico en viñedos afectados por clorosis férrica

La deficiencia de hierro inducida en terrenos calizos, suele ir acompañada de desequilibrios en la nutrición de otros elementos. Es interesante desarrollar métodos que permitan monitorizar el estado nutricional, como las medidas de fluorescencia de la clorofila, para su aplicación en viticultura de precisión. Estos métodos podrían servir tanto para diseñar estrategias más eficientes para la corrección de carencias, como para elaborar mapas de rendimiento y calidad en viñedos. La deficiencia provoca una acumulación de Mn en los peciolos y una reducción de la concentración foliar de clorofilas, carotenoides y antocianinas. La clorosis férrica se ha traducido en un menor vigor y rendimiento del viñedo, dando mayores contenidos fenólicos y sólidos solubles en mostos. Fo y Fv/Fm se han correlacionado significativamente con los niveles de clorosis férrica y de nutrición de K, Mg y Mn. La ratio Fo/Fv ha sido especialmente sensible a los niveles nutricionales de Mn.Departamento de Producción Vegetal y Recursos Forestale

Macrodistrofia lipomatosa en el pie: A propósito de un caso y revisión de la literatura

La macrofistrofia lipomatosa es una forma de gigantismo localizado poco frecuente y de causa desconocida, se caracteriza por un gran aumento del crecimiento de todos los elementos mesenquimales, en particular el tejido fibroadiposo de uno o varios dedos del pie o de la mano. Nosotros presentamos un paciente con una deformidad estática en el primer dedo del pie derecho, con una discusión de los hallazgos clínicos, patológicos y radiológicos, así como una revisión de la bibliografía.Macrodystrophia Lipomatosa, a rare form of localized gigantism of unknown cause, is characterized by a dramatic overgrowth of all the mesenchymal elements, paricularly the fibroadipose tissue, of one or more digits of the foot or hand. We report the case of an patient, who had a static deformity of the first toe of the right food. The clinical, pathologic, and roentgenographic findings are discussed and review of the literature is provided