Fabrication of chromium carbide cermets by electric resistance sintering process: Processing, microstructure and mechanical properties

Chromium carbide-based cermets are suitable for use in abrasive and corrosive environments. This work presents the fabrication of chromium carbide-based cermets by a very fast sintering process: Electric Resistance Sintering. The thermal cycle duration was less than 1 s and without protective atmosphere. Two different compositions were studied: Cr3C2-25NiCr (wt%) and WC-20Cr3C2-7Ni (wt%). Microstructure and crystallographic phases of the initial powders and sintered materials are presented. In addition, hardness and toughness were characterized and compared to conventional materials. One important issue of ERS is the size and homogeneity of the pieces. This work presents the also the fabrication of a mining wear piece and some aspects about scaling up.This work is financially supported by the European Institute of Innovation and Technology (EIT Raw Materials), a body of European Union (Horizon 2020 Framework Programme) under the project FASTRAM

Field Dependence of the Electron Spin Relaxation in Quantum Dots

Interaction of the electron spin with local elastic twists due to transverse phonons has been studied. Universal dependence of the spin relaxation rate on the strength and direction of the magnetic field has been obtained in terms of the electron gyromagnetic tensor and macroscopic elastic constants of the solid. The theory contains no unknown parameters and it can be easily tested in experiment. At high magnetic field it provides parameter-free lower bound on the electron spin relaxation in quantum dots.Comment: 4 PR pages, no figure

Migraciones de valencianos y sus descendientes en Cataluña. Un ejemplo de ciencia ciudadana

El objetivo de este trabajo es realizar una valoración crítica del uso de la ciencia ciudadana para llevar a cabo un estudio sociodemográfico sobre la migración valenciana y su descendencia en Cataluña. Para ello se explicará cómo se pensó y elaboró el proyecto de Veus Valencianes, su puesta en marcha y el alcance que tuvo. Únicamente se analizarán los principales resultados obtenidos, ya que el objetivo principal es valorar el éxito final del método, así como los pros y contras de utilizar la ciencia ciudadana en este tipo de estudios de ciencias sociales, todavía muy minoritarios en el uso de esta metodología.The aim of this work is to make a critical assessment of the use of Citizen Science to carry out a sociodemographic study on Valencian migration and its descendants in Catalonia. For this purpose, it will be explained how Veus Valencianes project was conceived and designed, and how was its implementation and scope. Only the main results will be analyzed, since the purpose of this work is to evaluate the final success of the method, as well as the pros and cons of using Citizen Science for this type of Social Sciences studies, still very minority in the use of this methodology

GWAL – Gestor Web d’Activitats d’interès cultural, Lúdic i esportiu

Desenvolupar un sistema via web per a la gestió d'un centre lúdic (p.ex. un centre cívic) que doni suport a l'administració de activitats, recursos i usuaris. Això inclou: gestio de recursos: sales, professionals, materials, gestió de usuaris: passwords, privilegis, info personal, perfil d'usuari, gestio d'activitats: definició, inscripcions, seguiments, ..

Impact of phosphate dosing on the microbial ecology of drinking water distribution systems: fieldwork studies in chlorinated networks

Phosphate is routinely dosed to ensure regulatory compliance for lead in drinking water distribution systems. Little is known about the impact of the phosphate dose on the microbial ecology in these systems and in particular the endemic biofilms. Disturbance of the biofilms and embedded material in distribution can cause regulatory failures for turbidity and metals. To investigate the impact of phosphate on developing biofilms, pipe wall material from four independent pipe sections was mobilised and collected using two twin-flushing operations a year apart in a chlorinated UK network pre- and post-phosphate dosing. Intensive monitoring was undertaken, including turbidity and water physico-chemistry, traditional microbial culture-based indicators, and microbial community structure via sequencing the 16S rRNA gene for bacteria and the ITS2 gene for fungi. Whole metagenome sequencing was used to study shifts in functional characteristics following the addition of phosphate. As an operational consequence, turbidity responses from the phosphate-enriched water were increased, particularly from cast iron pipes. Differences in the taxonomic composition of both bacteria and fungi were also observed, emphasising a community shift towards microorganisms able to use or metabolise phosphate. Phosphate increased the relative abundance of bacteria such as Pseudomonas, Paenibacillus, Massilia, Acinetobacter and the fungi Cadophora, Rhizophagus and Eupenicillium. Whole metagenome sequencing showed with phosphate a favouring of sequences related to Gram-negative bacterium type cell wall function, virions and thylakoids, but a reduction in the number of sequences associated to vitamin binding, methanogenesis and toxin biosynthesis. With current faecal indicator tests only providing risk detection in bulk water samples, this work improves understanding of how network changes effect microbial ecology and highlights the potential for new approaches to inform future monitoring or control strategies to protect drinking water quality

Magnetically tunable bidirectional locomotion of a self-assembled nanorod-sphere propeller

Field-driven direct assembly of nanoscale matter has impact in disparate fields of science. In microscale systems, such concept has been recently exploited to optimize propulsion in viscous fluids. Despite the great potential offered by miniaturization, using self-assembly to achieve transport at the nanoscale remains an elusive task. Here we show that a hybrid propeller, composed by a ferromagnetic nanorod and a paramagnetic microsphere, can be steered in a fluid in a variety of modes, from pusher to puller, when the pair is dynamically actuated by a simple oscillating magnetic field. We exploit this unique design to build more complex structures capable of carrying several colloidal cargos as microscopic trains that quickly disassemble at will under magnetic command. In addition, our prototype can be extended to smaller nanorods below the diffraction limit, but still dynamically reconfigurable by the applied magnetic field.Peer ReviewedPostprint (published version