Sintering and mechanical properties of cemented carbides based on tungsten carbide and multicomponent metallic alloys.

Cemented carbides are composite materials used in a wide variety of applications requiring the right combination of mechanical strength and wear resistance under harsh environments (i.e. metal cutting and shaping, civil engineering, mining, valves for the chemical industry, etc). The most common compositions comprise tungsten carbide grains bonded with a cobalt based metallic matrix. The reason is twofold. On the one hand, WC-Co materials are relatively easy to sinter to full density state with the adequate processing methodology and, on the other, a wide range of useful properties can be obtained by changing the WC grain size and the WC/Co ratio. Nevertheless, the use and availability of cobalt are presently jeopardized by both its new classification as toxic substance (REACH regulations) and the growing demand of this metal for making Li-ion batteries for electrical vehicles. The present thesis is focused on studying the sintering behavior and mechanical properties of WC-metal systems in which pure cobalt is replaced by different combinations of metals. Two promising candidates have been found: WC-NiCoCrTiAl cemented carbides These materials were designed starting from WC-NiCoCr compositions with a Ni/Co ratio equal to one. The main challenge was to increase the hardness of these compositions since it is too low compared with that of WC-Co grades. This was achieved firstly by alloying the binder phase with aluminum and, afterwards, inducing gamma prime precipitation by aging treatments. Two different aluminum containing compounds were investigated in order to avoid catastrophic oxidation of aluminum during PM processing: AlN and TiAl3. The latter produced the best results concerning sinterability and precipitation hardening effects. WC-Ni-Co-Cr-Ti-Al materials were obtained in fully dense form by using HIP after sintering technique, a process compatible with industrial processing technologies like Sinter HIP. Aging experiments show that hardness peaks occur at lower temperatures as the Al content of the binder phase increases. Apart from hardness, transverse rupture strength (TRS) was also measured in selected WC-NiCoCrTiAl compositions in both as-HIPed and solution-aged conditions. Results are only 15% lower than those reported for WC-Co materials with similar WC grain sizes and WC/metal ratios. These results also suggest that, like in as-cast Ni superalloys, the properties of the binder phase would be retained at temperatures below those used in aging treatments. WC-FeNiCoCr cemented carbides WC-Fe-Ni-Co-Cr compositions were designed following an alternative approach. In this case, the aim was to obtain a metallic binder with no precipitation of free carbon or any secondary carbide (including those of chromium). This was achieved by starting from WC-Fe-Ni-Co-Cr3C2 powder mixtures with a constant proportion between Fe, Ni and Co equal to 40/40/20. Chromium and carbon contents have been modified in order to find the upper and lower bounds defining the “so-called” carbon windows. In addition, shrinkage kinetics have been thoroughly studied in order to define a robust sintering process for both coarse and submicron WC powders. Results of calorimetric experiments have been used to improve the description of the W-C-Fe-Ni-Co quinary system for 40Fe-40Ni-20Co composition by means of ThermoCalc® software. In this case, mechanical tests confirmed that the values of hardness and transverse rupture strength are within tolerances of those reported for WC-Co grades with similar binder contents and WC grain sizes, provided that precipitation of undesired phases is avoided.Los carburos cementados son materiales compuestos utilizados en una amplia variedad de aplicaciones que requieren la combinación correcta de resistencia mecánica y resistencia al desgaste en entornos hostiles (es decir, corte y conformado de metales, ingeniería civil, minería, válvulas para la industria química, etc). Las composiciones más comunes comprenden granos de carburo de tungsteno unidos con una matriz metálica de cobalto. La razón es doble. Por un lado, los materiales WC-Co son relativamente fáciles de sinterizar a un estado de densidad completa con la metodología de procesamiento adecuada y, por otro lado, una amplia variedad de propiedades útiles se pueden obtener variando el tamaño de grano de WC y la relación WC/Co. Sin embargo, el uso y la disponibilidad de cobalto está actualmente en peligro tanto por su nueva clasificación como sustancia tóxica (normativa REACH) como por la creciente demanda de este metal para la fabricación de baterías de iones de litio para vehículos eléctricos. La presente tesis se centra en el estudio de la sinterización y las propiedades mecánicas de sistemas WC-metal en los que el cobalto puro es reemplazado por diferentes combinaciones de metales. Se han encontrado dos candidatos prometedores: Carburos cementados WC-NiCoCrTiAl Estos materiales fueron diseñados a partir de composiciones WC-NiCoCr con una relación Ni/Co igual a uno. El principal reto fue aumentar la dureza de estas composiciones ya que es muy baja en comparación con los grados WC-Co. Esto se logró en primer lugar mediante la aleación de la fase ligante con aluminio y, posteriormente, induciendo la precipitación gamma prima mediante tratamientos de envejecimiento. Se investigaron dos fuentes de aluminio distintas para evitar una oxidación catastrófica del aluminio durante el procesamiento PM: AlN y TiAl3. Este último produjo los mejores resultados en cuanto a la sinterabilidad y los efectos de endurecimiento por precipitación. Los materiales WC-Ni-Co-Cr-Ti-Al fueron obtenidos en forma totalmente densa mediante el uso de HIP después de la sinterización, un proceso compatible con tecnologías de procesamiento industrial como Sinter HIP. Los experimentos de envejecimiento muestran que la dureza alcanza su punto máximo a temperaturas más bajas a medida que aumenta el contenido de Al de la fase ligante.Además de la dureza, la resistencia a la ruptura transversal (TRS) también se midió en composiciones seleccionadas de WC-NiCoCrTiAl tanto en condiciones de HIPed como de envejecimiento en solución. Los resultados son solo el 15% más bajos que los reportados para materiales WC-Co con tamaños de grano de WC y proporciones WC/metal similares. Estos resultados sugieren también que, al igual que en las superaleaciones base Ni, las propiedades de la fase ligante se mantendrían a temperaturas inferiores a las utilizadas en los tratamientos de envejecimiento. Carburos cementados WC-FeNiCoCr Las composiciones WC-Fe-Ni-Co-Cr fueron diseñadas siguiendo un enfoque alternativo. En este caso, el objetivo era obtener un ligante metálico sin precipitación de carbono libre ni ningún carburo secundario (incluidos los de cromo). Esto se logró partiendo de mezclas en polvo WC- Fe-Ni-Co-Cr3C2 con una proporción constante entre Fe, Ni y Co igual a 40/40/20. Los contenidos en cromo y carbono han sido modificados para encontrar los límites superior e inferior que definen "las llamadas" ventanas de carbono. Además, la cinética de contracción se ha estudiado a fondo para definir un proceso robusto de sinterización para polvos de WC gruesos y submicra. Los resultados de los experimentos calorimétricos se han utilizado para mejorar la descripción del sistema quinario W-C-Fe-Ni-Co para la composición 40Fe-40Ni-20Co mediante el software ThermoCalc®. En este caso, las pruebas mecánicas confirmaron que los valores de dureza y de resistencia a la ruptura transversal están dentro de las tolerancias reportadas para los grados WC-Co con contenidos de ligante y tamaños de grano de WC similares, siempre que se evite la precipitación de fases no deseadas

Digital image correlation after focused ion beam micro-slit drilling: A new technique for measuring residual stresses in hardmetal components at local scale

A new method has been developed for measuring residual stresses at the surface of hardmetal components with higher spatial resolution than standard X-ray diffraction methods. It is based on measuring the surface displacements produced when stresses are partially released by machining a thin slit perpendicularly to the tested surface. Slit machining is carried out by focused ion beam (FIB). Measurement of the displacement fields around the FIB slit are performed by applying an advanced digital image correlation algorithm based on Fourier analysis with sub-pixel resolution. This method compares SEM images of the same area of the hardmetal surface before and after slitting. The method has been successfully applied to as-ground and femto-laser textured surfaces showing good correlation with the standard sin2 ψ XRD technique. It is concluded that texturing induced by laser pulses in the femtoseconds regime is not perfectly adiabatic, since residual stresses are reduced by 15

Digital image correlation after focused ion beam micro-slit drilling: A new technique for measuring residual stresses in hardmetal components at local scale

A new method has been developed for measuring residual stresses at the surface of hardmetal components with higher spatial resolution than standard X-ray diffraction methods. It is based on measuring the surface dis-placements produced when stresses are partially released by machining a thin slit perpendicularly to the tested surface. Slit machining is carried out by focused ion beam (FIB). Measurement of the displacement fields around the FIB slit are performed by applying an advanced digital image correlation algorithm based on Fourier analysis with sub-pixel resolution. This method compares SEM images of the same area of the hardmetal surface before and after slitting. The method has been successfully applied to as-ground and femto-laser textured surfaces showing good correlation with the standard sin2 psi XRD technique. It is concluded that texturing induced by laser pulses in the femtoseconds regime is not perfectly adiabatic, since residual stresses are reduced by 15%

Morphofunctional and Molecular Assessment of Nutritional Status in Head and Neck Cancer Patients Undergoing Systemic Treatment: Role of Inflammasome in Clinical Nutrition

Malnutrition in patients with head and neck cancer is frequent, multifactorial and widely associated with clinical evolution and prognosis. Accurate nutritional assessments allow for early identification of patients at risk of malnutrition in order to start nutritional support and prevent sarcopenia. We aimed to perform a novel morphofunctional nutritional evaluation and explore changes in inflammasome-machinery components in 45 patients with head and neck cancer who are undergoing systemic treatment. To this aim, an epidemiological/clinical/anthropometric/biochemical evaluation was performed. Serum RCP, IL6 and molecular expression of inflammasome-components and inflammatory-associated factors (NOD-like-receptors, inflammasome-activation-components, cytokines and inflammation/apoptosis-related components, cell-cycle and DNA-damage regulators) were evaluated in peripheral-blood mononuclear-cells (PBMCs). Clinical-molecular correlations/associations were analyzed. Coherent and complementary information was obtained in the morphofunctional nutritional assessment of the patients when bioimpedance, anthropometric and ultrasound data were analyzed. These factors were also correlated with different biochemical and molecular parameters, revealing the complementary aspect of the whole evaluation. Serum reactive C protein (RCP) and IL6 were the most reliable parameters for determining patients with decreased standardized phase angle, which is associated with increased mortality in patients with solid malignancies. Several inflammasome-components were dysregulated in patients with malnutrition, decreased phase angle and dependency grade or increased circulating inflammation markers. A molecular fingerprint based on gene-expression of certain inflammasome factors (p27/CCL2/ASC) in PBMCs accurately differentiated patients with and without malnutrition. In conclusion, malnutrition induces a profound alteration in the gene-expression pattern of inflammasome-machinery components in PBMCs. A comprehensive nutritional assessment including novel morphofunctional techniques and molecular markers allows a broad characterization of the nutritional status in cancer patients. Profile of certain inflammasome-components should be further studied as potential targets for nutrition-focused treatment strategies in cancer patients

Safety and Efficacy of Sofosbuvir plus Simeprevir in a Spanish Cohort of 622 Cirrhotic Patients Infected with Genotypes 1 or 4

Presentation Poste

Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives

RICORS2040 : The need for collaborative research in chronic kidney disease

Chronic kidney disease (CKD) is a silent and poorly known killer. The current concept of CKD is relatively young and uptake by the public, physicians and health authorities is not widespread. Physicians still confuse CKD with chronic kidney insufficiency or failure. For the wider public and health authorities, CKD evokes kidney replacement therapy (KRT). In Spain, the prevalence of KRT is 0.13%. Thus health authorities may consider CKD a non-issue: very few persons eventually need KRT and, for those in whom kidneys fail, the problem is 'solved' by dialysis or kidney transplantation. However, KRT is the tip of the iceberg in the burden of CKD. The main burden of CKD is accelerated ageing and premature death. The cut-off points for kidney function and kidney damage indexes that define CKD also mark an increased risk for all-cause premature death. CKD is the most prevalent risk factor for lethal coronavirus disease 2019 (COVID-19) and the factor that most increases the risk of death in COVID-19, after old age. Men and women undergoing KRT still have an annual mortality that is 10- to 100-fold higher than similar-age peers, and life expectancy is shortened by ~40 years for young persons on dialysis and by 15 years for young persons with a functioning kidney graft. CKD is expected to become the fifth greatest global cause of death by 2040 and the second greatest cause of death in Spain before the end of the century, a time when one in four Spaniards will have CKD. However, by 2022, CKD will become the only top-15 global predicted cause of death that is not supported by a dedicated well-funded Centres for Biomedical Research (CIBER) network structure in Spain. Realizing the underestimation of the CKD burden of disease by health authorities, the Decade of the Kidney initiative for 2020-2030 was launched by the American Association of Kidney Patients and the European Kidney Health Alliance. Leading Spanish kidney researchers grouped in the kidney collaborative research network Red de Investigación Renal have now applied for the Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS) call for collaborative research in Spain with the support of the Spanish Society of Nephrology, Federación Nacional de Asociaciones para la Lucha Contra las Enfermedades del Riñón and ONT: RICORS2040 aims to prevent the dire predictions for the global 2040 burden of CKD from becoming true

Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives.Versión del edito

Actas de las V Jornadas ScienCity 2022. Fomento de la Cultura Científica, Tecnológica y de Innovación en Ciudades Inteligentes

ScienCity es una actividad que viene siendo continuada desde 2018 con el objetivo de dar a conocer los conocimientos y tecnologías emergentes siendo investigados en las universidades, informar de experiencias, servicios e iniciativas puestas ya en marcha por instituciones y empresas, llegar hasta decisores políticos que podrían crear sinergias, incentivar la creación de ideas y posibilidades de desarrollo conjuntas, implicar y provocar la participación ciudadana, así como gestar una red internacional multidisciplinar de investigadores que garantice la continuación de futuras ediciones. En 2022 se recibieron un total de 48 trabajos repartidos en 25 ponencias y 24 pósteres pertenecientes a 98 autores de 14 instituciones distintas de España, Portugal, Polonia y Países Bajos.Fundación Española para la Ciencia y la Tecnología-Ministerio de Ciencia, Innovación y Universidades; Consejería de la Presidencia, Administración Pública e Interior de la Junta de Andalucía; Estrategia de Política de Investigación y Transferencia de la Universidad de Huelva; Cátedra de Innovación Social de Aguas de Huelva; Cátedra de la Provincia; Grupo de investigación TEP-192 de Control y Robótica; Centro de Investigación en Tecnología, Energía y Sostenibilidad (CITES

Plasma lipid profiles discriminate bacterial from viral infection in febrile children

Fever is the most common reason that children present to Emergency Departments. Clinical signs and symptoms suggestive of bacterial infection ar