Small-scale mechanical response of cemented carbides: Correlation between mechanical properties and microstructure

The unique combination of hardness, toughness and wear resistance exhibited by heterogeneous hard materials (e.g. cemented carbides, PCD composites, PcBN systems and generic hard coating/substrate combinations) has made them preeminent material choices for extremely demanding applications, such as metal cutting/forming tools or mining bits, where improved and consistent performance together with high reliability are required. The remarkable mechanical properties of these materials results from a two-fold effectiveness associated with their intrinsic composite character. On the one hand in terms of composite nature: combination of completely different phases (hard, brittle and soft, ductile constituents) with optimal interface properties. On the other hand as related to composite assemblage: two interpenetrating-phase networks where toughening is optimized through different mechanisms depending on the relatively different chemical nature among them. In particular, this presentation is focused on WC-Co hardmetals, as reference hard material. Large number of studies has been reported, mainly focused on the mechanical behavior of this composite. On the other hand, information on the small-scale mechanical response of these materials is rather scarce. This is particularly true regarding experimental data and analysis on the influence of phase nature, crystal orientation (anisotropy) and interfacial adhesion strength on hardness, deformation and/or damage mechanisms. It is clear that knowledge of these issues is crucial not only to improve the performance of hardmetals but also to develop ceramic-metal composites beyond WC-Co systems. A systematic micro- and nanomechanical study of the mechanical response of several microstructurally different WC-Co grades is presented. In doing so, nanoindentation technique is implemented and corresponding deformation/damage mechanisms are also investigated. In general, five different approaches are followed to accomplish the main goal of this research: (1) assessment of intrinsic hardness values and main deformation mechanisms as a function of crystal orientation for the carbide phase at room temperature (RT) and also at high temperature (from RT to 600 ºC), (2) determination of effective hardness and flow stress of the metallic binder through massive nanoindentation and statistical analysis, (3) evaluation of the Hall-Petch parameters for the WC-Co as a function of a microstructural parameter (mean free path) by using the methodology presented above, (4) correlation of the microstructure with the hardness and elastic modulus map by using high indentation speed tests, and (5) study of the stress-strain response by means of ex/in-situ compression of micropillars. It is found that WC-Co composites are strongly anisotropic in terms of hardness at the small scale (microstructure), being the WC hardness for the basal plane about 20-30% higher than for the prismatic and pyramidal planes. It implies consideration of carbides with different crystal orientations as distinct phases for statistical analysis of massive nanoindentation data. Implementation of such testing/analysis protocol indicates a flow stress for the constrained Co-based binder of about 2.6-3.5 GPa. By plotting of the experimentally data as a function of the binder mean free path results in a Hall-Petch strengthening relationship. Finally, the compression of micropillars points out that main deformation mechanisms are located in the metallic binder although close to the strong interface exhibited by these materials

Management of wet age-related macular degeneration in Spain: challenges for treat and extend implementation in routine clinical practice

Age-related macular degeneration; Ophthalmology services; Anti-VEGFDegeneración macular relacionada con la edad; Servicios de oftalmología; Anti-VEGFDegeneració macular relacionada amb l’edat; Serveis d’oftalmologia; Anti-VEGFPurpose. To ascertain wet AMD (wAMD) management patterns in Spain. Methods. A two-round Delphi study conducted through a questionnaire-based survey designed from literature review and validated by an independent Steering Committee. Results. Forty-nine retina specialists experienced in wAMD participated by answering the two-round study questionnaire. Retina specialists are the main responsible for wAMD diagnosis and monitoring, including visits and associated procedures, with a median time per visit of 15 minutes. Standard treatment strategies are based on anti-VEGF administration, including standard loading dose administration followed by maintenance with aflibercept or ranibizumab (81% of patients). Although treat and extend (T&E) dosing strategy is considered as optimal for wAMD management (78% of the panelists), the main routine healthcare limitations (i.e., visits overload, reduced staff, short visit time, coordination issues, lack of facilities) conduct to self-defined “flexible” strategies, based on T&E and pro-re-nata (PRN) protocols. Conclusion. Proactive treatment patterns (T&E) are the preferred ones by the retina specialists in Spain. However, their proper implementation is difficult due to healthcare resource limitations, as well as organisation and logistic issues. The use of anti-VEGF agents with longer duration of action could facilitate the use of strict T&E approaches according to routine clinical practices

Children Rights and Global Citizenship: an Approach from the educational Community

La Convención de los Derechos del Niño (CDN) es una herramienta fundamental para la educación de niños, niñas y adolescentes. Ésta debe entenderse como el marco de referencia universal que contribuye a formar niños y niñas capacitados para ejercer sus derechos de ciudadanía. Sin embargo, conocemos muy poco sobre cómo los derechos de la infancia y la ciudadanía global se integran en el sistema educativo español. El objetivo de este trabajo es identificar las necesidades formativas que tiene la comunidad educativa en relación a la CDN desde las dimensiones cognitiva, metodológica y actitudinal. Se trata de una investigación cualitativa que ha contado con la participación de 124 personas representantes de la comunidad educativa (alumnado, docentes, padres y madres) distribuidas en 14 grupos de discusión desarrollados en 11 Comunidades Autónomas del territorio español. El análisis de contenido muestra la escasa incorporación en los centros escolares de la CDN, así como una la visión parcial de ésta por parte de los integrantes de la comunidad educativa. Se observan necesidades en la falta de estrategias de enseñanza-aprendizaje que fomenten la autonomía y la participación infantil en el aula y el centro. Finalmente, se observa la dificultad de posicionar a la infancia como sujeto de derechos con facultades para ejercer su ciudadanía.Esta investigación ha sido posible gracias a la financiación de la Agencia Española de Cooperación Internacional para el Desarrollo (AECID) y de UNICEF – Comité Español, en el marco del proyecto “Fomento de la Educación para el Desarrollo en la Educación Formal” 2010 – 2012. El contenido de esta publicación es responsabilidad exclusiva de los autores y no refleja necesariamente la opinión de la AECID

Actividades para la formación de profesionales reflexivos en la acción: una propuesta de desarrollo de competencias desde los créditos prácticos en los estudios de Maestro de Educación Especial

Las experiencias educativas en los centros de Educación Infantil y Primaria de nuestro entorno próximo forman parte de los recursos esenciales para la formación de los futuros maestros. De manera continuada a lo largo de segundo y tercer curso de Magisterio esta realidad constituye el campo de aprendizaje de nuestros estudiantes. En él deberán desarrollar una actividad relacionada con la adquisición del conocimiento teórico en la Universidad. En este marco se reclama a los estudiantes que, además de la observación de los profesionales expertos, sean también docentes diseñando y llevando a término con alumnos de seis a doce años distintas experiencias, que posteriormente deberán analizar y evaluar a partir de distintas estrategias.Educational experiences in Nursery and Primary schools of our local area are essential resources to train future teachers. During the second and third year of the teacher training degree in Educational needs, our students are continually involved in these schools. Throughout these teaching placements they have to develop an activity in relation to the theoretical knowledge acquired at University. The students are asked not only to observe the experienced professionals, but also to act as teachers, designing and putting into practice different experiences with children aged six to twelve. Later, they will have to analyse and evaluate these experiences using different strategies

Evaluation of a workshop to teach a new surgical technique in abdominal wall reconstruction.

Purpose Assess the utility of a hands-on workshop on abdominal wall reconstruction for teaching the posterior components separation (PCS) with transversus abdominis release. Methods Our department has been organizing a training course on abdominal wall reconstruction for the last 6 years. It is a 2-day-long course and 10–12 surgeons with experience in abdominal wall surgery attend to every course. The first day is dedicated to theoretical lectures and two simultaneous live surgeries, and the second day there is a cadaver dissection. Feedback from the trainees was collected at the end of the workshop. A survey was sent to all the surgeons who had completed the course at least a year ago, to inquire how the course had improved their surgical practice. Results From 2013 to April 2017, we have made 15 editions of the course. A total of 192 surgeons from Europe, South Africa and Middle East attended. All the surgeons answered the survey that was carried out at the end of the course. It showed a very high level of satisfaction in more than 98% of the cases. The second survey was answered by 79 surgeons (41.15%). 96% of the surgeons had modified, after attending the course, their way of dealing with complex abdominal wall problems. Only 29% of the surgeons had made a TAR before attending the course, while 86% are performing it after attending the course and 60% do it on a regular basis. In fact, 43% of surgeons have performed more than five posterior component separations in the last year. Conclusions A workshop of abdominal wall surgery that combines live surgery, theoretical content and a cadaver lab can be a very useful tool to expand the use of new surgical techniques.pre-print424 K