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The correlation between microstructure, crystallographic orientation and grain boundaries characteristics of an austenitic high manganese steel was systematically investigated. The as-received and cold-rolled specimens with 50% and 70% reduction were analyzed using Scanning Electron Microscopy (SEM), Electron Back-Scattered Diffraction (EBSD) and X-ray diffraction techniques. A significant increase in the fraction of low-energy S3 twin boundaries, from 16.21% to 24.41%, was found in the 70% deformed sample. This was coupled with the formation of {011} austenitic structure, and occurrence of twinning-induced plasticity. The ductile-brittle fracture mode observed in the 70% cold rolled sample, which can be attributed to the formation of the high fraction of low-energy S3 twin boundaries, minimized both the localized stored strain energy and lattice misfit and promoted dislocation glide. A potential employment of the investigated steel in the petroleum industry is discussed., Peer Reviewed, Postprint (published version)

Nickel-based superalloys are extensively used in the aerospace and power generation industries due to their excellent mechanical properties at elevated temperatures and good corrosion resistance. Typically, these alloys require accomplishing critical standards during their manufacturing process. In this study, an Inconel 718 (IN718) Ni-based superalloy was subjected to a delta-processing treatment (DP718) and subsequently deformed at high temperature. Samples were compressed below and above the d-solvus temperature at two different strain rates of 0.001 s-1 and 0.01 s-1. A detailed microstructural characterization was carried out by the electron backscattered diffraction technique (EBSD). Kikuchi patterns and the orientation relationship of the d-phase were identified. For samples deformed above the d-solvus at 0.01 s-1, an increase in the percentage of low angle grain boundaries (LAGB) within deformed grains and a decrease in high angle grain boundaries (HAGB) were observed. Comprehensive observation of the microstructural evolution of IN718 subjected to DP718 using orientation map images was also performed., Peer Reviewed, Postprint (published version)

The pitting corrosion of an aluminum alloy AA1050 after being processed by continuous closed die forging (CCDF) was evaluated by cyclic potentiodynamic polarization (CPP). Microstructure evolution, mechanical and corrosion behaviors were studied as a function of the total strain imposed. The CCDF process was carried out at 0, 16 and 24 passes with loading times of 10 and 15¿s. The electron backscatter diffraction (EBSD) analysis revealed a grain refinement of 0.78¿µm after 24 passes, which promoted an increment in the yield strength (YS), ultimate tensile strength (UTS) and vickers hardness (HV) by a factor of 9, 3 and 2 respectively; but the uniform strain and strain to rupture decreased by 93% and 72% respectively. Resistance to corrosion after 16 and 24 passes was compared with the reference material (0 passes), using CPP in a Na2S04 0.1¿mol/l +100¿mg/l of NaCl electrolyte. Results showed that the specimens with 24 passes decreased its corrosion rate one order of magnitude. In addition, specimens with very fine grain sizes have shown nobler pitting potential and lower pitting volume fraction than coarse grain specimens., Peer Reviewed, Postprint (author's final draft)

337 p., A pesar de que el Sedimento proporciona un registro histórico de la contaminación, la legislación europea, estatal y autonómica no le otorga el mismo nivel de relevancia que al Agua en la evaluación del estado ecológico de las cuencas hidrográficas. Por tanto, el objetivo principal de esta tesis fue remarcar el papel fundamental de los sedimentos en la dinámica de contaminantes en los ecosistemas acuáticos, y valorar el efecto de la gestión de vertidos de aguas residuales urbano-industriales sobre el estado ecológico de la cuenca del río Deba, empleando indicadores de calidad química y fisicoquímica, así como biológica.Se ha concluido que, al menos, un muestreo y análisis anual del sedimento aporta una valiosa información prospectiva sobre el estado y evolución de la calidad de las aguas en los ríos, identificando aquellas zonas susceptibles de polución y posibilitando la definición de nuevas estrategias futuras de sostenibilidad. Concretamente, los vertidos de aguas residuales tratadas y no tratadas aumentan el contenido en materia orgánica, nutrientes y metales, tanto del agua como del sedimento. Asimismo, no solo alteran la distribución espacial y composición de las comunidades bacterianas involucradas en los ciclos del N y S, sino también la actividad microbiana desnitrificante. Finalmente, se ha demostrado que la bioaccesibilidad y, por tanto, la toxicidad de los metales sobre la salud humana depende de su especiación química que obedece, a su vez, a la composición mineralógica y elemental del sedimento.

In many urban catchments, the discharge of effluents from wastewater treatment plants (WWTPs), as well as untreated wastewaters (UWWs), presents a major challenge for the maintenance of river sediment and water quality. The discharge of these effluents cannot only increase the concentration of metals, nutrients and organic compounds in fluvial ecosystems, but also alter the abundance, structure and function of river bacterial communities. Here, we present data on chemical and biological quality parameters in wastewater-impacted and non-impacted river surface sediment and water samples. Overall, the concentration of nutrients (inorganic nitrogen) and some heavy metals (Zn, Ni and Cr) was positively correlated with the nirS/16S rRNA ratio, while nirK- and nosZ-denitrifier populations were negatively affected by the presence of ammonium in sediments. Bacterial community structure was significantly correlated with the (i) combined influence of nutrient and metal concentrations, (ii) the contamination level (non-impacted vs. impacted sites), (iii) type of contamination (WWTP or UWW), and (iv) location of the sampling sites. Moreover, the higher abundance of five genera of the family Rhodocyclaceae detected in wastewater-impacted sites is also likely to be an effect of effluent discharge. The data presented here complement a broader study (Martinez-Santos et al., 2018) [1] and they are particularly useful for those interested in understanding the impact of wastewater effluents on the abundance, structure and function of river bacterial communities involved in nitrogen cycling.

Obstructive nephropathy constitutes a major cause of pediatric renal progressive disease. The mechanisms leading to disease progression are still poorly understood. Kidney fibrotic lesions are reproduced using a model of partial unilateral ureteral obstruction (pUUO) in newborn mice. Based on data showing significant mast cell (MC) infiltration in patients, we investigated the role of MC and murine MCPT4, a MC-released chymase, in pUUO using MC- (W-sh/sh), MCPT4-deficient (Mcpt4(-/-)), and wild-type (WT) mice. Measurement of kidney length and volume by magnetic resonance imaging (MRI) as well as postmortem kidney weight revealed hypotrophy of operated right kidneys (RKs) and compensatory hypertrophy of left kidneys. Differences between kidneys were major for WT, minimal for Wsh/sh, and intermediate for Mcpt4(-/-) mice. Fibrosis development was focal and increased only in WT-obstructed kidneys. No differences were noticed for local inflammatory responses, but serum CCL2 was significantly higher in WT versus Mcpt4(-/-) and Wsh/sh mice. Alpha-smooth muscle actin (alpha SMA) expression, a marker of epithelial-mesenchymal transition (EMT), was high in WT, minimal for W-sh/sh, and intermediate for Mcpt4(-/-) RK. Supernatants of activated MC induced aSMA in co-culture experiments with proximal tubular epithelial cells. Our results support a role of MC in EMT and parenchyma lesions after pUUO involving, at least partly, MCPT4 chymase. They confirm the importance of morphologic impairment evaluation by MRI in pUUO.

Since its introduction in 2003, alloy 718PlusTM spurred a lot of interest owing to its increased maximum service temperature over conventional Inconel 718 (704¿°C versus 650¿°C), good formability, and weldability together with its moderate cost. Understanding the high-temperature deformation characteristics and microstructural evolution is still of interest to many. It is known that the service performance and hot-flow behavior of this alloy are a strong function of the microstructure, particularly the grain size. To develop precise microstructure evolution models and foresee the final microstructure, it is important to understand how and under which forming conditions softening and precipitation processes occur concurrently. In this work, the softening behavior, its mechanisms, and the precipitation characteristics of 718PlusTM were investigated in two parallel studies. While cylindrical compression tests were employed to observe the hot-flow behavior, the precipitation behavior and other microstructural phenomena such as particle coarsening were tracked via hardness measurements. A precipitation–temperature–time (PTT) diagram was reported, and modeling of the flow curves via hyperbolic sine model was discussed in the light of the PTT behavior. Both “apparent” approach and “physically based” approach are implemented and two different sets of parameters were reported for the latter. Finally, recovery and recrystallization kinetics are described via Estrin–Mecking and Bergstrom, and Avrami kinetics, respectively., Peer Reviewed, Postprint (author's final draft)

El propósito de esta investigación fue analizar si, en la implementación del eje transversal cultural ambiental para el desarrollo sostenible, que enfatiza en problemáticas ambientales relacionadas con los contenidos del programa de Ciencias de séptimo5 año de la Educación Básica, puede ser factible la utilización de recursos tecnológicos. El diseño de la investigación fue cualitativo con enfoque dominante, con algunos elementos de corte cuantitativo, específicamente en el diseño de instrumentos y algunas técnicas de análisis de datos. El tipo de estudio se desarrolló con un enfoque multimétodo, tendencia que ha ido perfilando un estilo de investigación en el que se integran distintos métodos en un mismo diseño. Para ello, se determinaron cuáles fueron las estrategias didácticas y su relación con la tecnología y el eje cultura ambiental para el desarrollo sostenible, utilizadas por 6 docentes de Ciencia que se desempeñaron en séptimo año en instituciones públicas, localizadas en la provincia6 de Heredia del Valle Central de Costa Rica, así como la opinión de 20 estudiantes de ese mismo nivel. Dentro de los principales resultados se indican las opiniones de estudiantado, que expone su gran interés por recibir las lecciones que incorporen recursos tecnológicos. Por otro lado, algunos docentes se muestran no muy favorables ante el tema o desinteresados al respecto, además de no estar capacitados en su uso. Asimismo se identificó que este personal docente encuestado no desarrolla el eje curricular.