Diagramas de Frost

En este artículo vamos a aprender qué es un Diagrama de Frost, qué representa, para qué sirve y cuáles son sus principales características. También se explicará cómo construir un diagrama de Frost a partir de los datos contenidos en un diagrama de Latimer.Blasco Tamarit, ME. (2012). Diagramas de Frost. http://hdl.handle.net/10251/1682

Diagramas de Latimer

En este artículo vamos a aprender qué es un Diagrama de Latimer, qué representa, cuál es su utilidad y cuáles son sus principales características. Todo ello lo veremos a través de ejemplos para facilitar el aprendizaje de los conceptos básicos de este documento.Blasco Tamarit, ME. (2011). Diagramas de Latimer. http://hdl.handle.net/10251/1283

"En toda teoría hay algo de biografía". Entrevista a Verena Stolcke

En aquesta ocasió el Projecte Entrevistes2 entrevista a la catedràtica Verena Stolcke, sumant-se així als actes d'homenatge que se li van fer el maig de 2008, arran de la seva jubilació del Departament d'Antropologia Social i Cultural de la Universitat Autònoma de Barcelona, després de més de trenta anys exercint-hi la docència. A través de l'entrevista es pot conèixer part de la trajectòria personal i intel·lectual de la professora Stolcke, una biografia estretament vinculada als temes que l'han interessat i que ha desenvolupat al llarg de la seva obra.Paral·lelament a aquest recorregut vital la Dra. Stolcke ens ofereix la seva visió de la situació en què es trobava l'antropologia catalana i espanyola quan va arribar a casa nostra, així com un diagnòstic de la situacióactual de la disciplina, que afronta un dels seus reptes més importants amb el procés d'adaptació a l'Espai Europeu d'Educació Superior (conegut com a Procés Bolonya).En esta ocasión, el Proyecto Entrevistas entrevista a la catedrática Verena Stolcke. De esta forma se suma a los actos de homenaje que se le rindieron en mayo de 2008, en ocasión de su jubilación del Departamento de Antropología Social y Cultural de la Universidad Autónoma de Barcelona, después de más de treinta años de docencia. A través de la entrevista se puede conocer parte de la trayectoria personal e intelectual de la profesora Stolcke, una biografía estrechamente relacionada con los temas que más le han interesado y que ha desarrollado a lo largo de su obra. Simultáneamente a este recorrido vital, la Dra. Stolcke nos ofrece su visión de la situación en que se hallaba la antropología catalana y española cuando llegó a nuestro país, así como un diagnóstico de la situación actual de la disciplina, que se enfrenta a uno de sus retos más importantes con el proceso de adaptación al Espacio Europeo de Educación Superior (o también llamado Proceso Bolonia)

Different applications of concept maps in Higher Education

Purpose: The aim of this work is to show different applications of concept maps in higher education, concretely in qualifications of the Polytechnic University of Valencia. Design/methodology/approach: Different methodologies have been used depending on the application of concept maps: as evaluation tool, as knowledge organizing tool, and as meaningful learning tool. Findings: Students consider the concept maps useful principally to select key ideas, to achieve a comprehensive view of the lesson, and to bring up the subject. Moreover, concept maps promote the meaningful and active learning, help students to understand, follow-up, and learn subjects with a high load of contents. Research limitations/implications: The most important limitation is the use of the concept maps in subjects with a high number of students. Practical implications: The realization of concept maps allows the student to develop generic competences. Originality/value: The originality of this work is to show how a same tool can be used in different subjects of different qualifications.Peer Reviewe

Imposed potential measurement to evaluate the pitting corrosion resistance and the galvanic behaviour of a highly alloyed austenitic stainless steel and its weldment in a LiBr solution at temperatures up to 150ºC

Pitting corrosion resistance and galvanic behaviour of Alloy 31, a highly alloyed austenitic stainless steel (UNS N08031), and its weldment were studied in a heavy brine LiBr solution 1080 g/l at different temperatures (75–150 °C) using electrochemical techniques. The Mixed Potential Theory was used to evaluate the galvanic corrosion between the base and welded metals. Cyclic potentiodynamic curves indicate that high temperatures make passivation and repassivation of pits difficult, because the whole passivation range and the repassivation potential values decrease with temperature. The critical pitting transition occurs between 100 and 125 °CWe wish to express our gratitude to Ministerio de Ciencia e Innovacion (CTQ2009-07518/PPQ) for its financial support, to Dr. Helena Elves from Krupp VDM for supplying the materials and to Dr. M. Asuncion Jaime for her translation assistance.Blasco Tamarit, ME.; García García, DM.; García Antón, J. (2011). Imposed potential measurement to evaluate the pitting corrosion resistance and the galvanic behaviour of a highly alloyed austenitic stainless steel and its weldment in a LiBr solution at temperatures up to 150ºC. Corrosion Science. 53(2):784-795. https://doi.org/10.1016/j.corsci.2010.11.013S78479553

Repassivation of the damage generated by cavitation on UNS N08031 in a LiBr solution by means of electrochemical techniques and Confocal Laser Scanning Microscopy

The objective of this work is to study the influence of cavitation on the corrosion behaviour of Alloy 31, a highly-alloyed austenitic stainless steel (UNS N08031), in a LiBr heavy brine solution (992 g/L) at 25 °C. The presence of cavitation shifted the OCP value towards the active direction by 708 mVAg/AgCl, increased anodic current densities and passivation current density, ip, and reduced the pitting potential, Ep. Repassivation behaviour of Alloy 31 has been investigated by using potentiostatic tests at different potentials. The current density transient obtained after interrupting cavitation was used to obtain the repassivation index, n, provided by the slope of the log i(t) vs. log t representation. The value of n decreased as the applied potential was increased, reaching values near zero for potentials close to the pitting potential. The damage generated during the potentiostatic tests has been quantified by means of Confocal Laser Scanning Microscopy

Effect of Temperature on Thermogalvanic Coupling of Alloy 31 in Libr Solutions Studied by Means of Imposed Potential Measurements

Corrosion resistance of Alloy 31, a highly alloyed stainless steel (UNS N08031) were studied in heavy brine LiBr solutions (400, 700 and 992 g/l) at different temperatures using electrochemical techniques. The mixed potential theory was used to evaluate thermogalvanic corrosion of Alloy 31 in the studied LiBr solutions. Potentiodynamic curves indicate that high temperatures favoured both cathodic and anodic processes, increasing passive current densities and decreasing the pitting potential. Generally, the cold electrode of the pair was the anode of the thermogalvanic cell

Thermogalvanic corrosion of Alloy 31 in different heavy brine LiBr solutions

Thermogalvanic corrosion generated between two electrodes of Alloy 31, a highly-alloyed austenitic stainless steel (UNS N08031), has been investigated imposing different temperature gradients in three deaerated LiBr solutions, under open circuit conditions by using a zero-resistance ammeter (ZRA). Besides EIS spectra were acquired in order to explain the obtained results. On the whole, cold Alloy 31 electrodes were anodic to hot Alloy 31 electrodes, since an increase in temperature favoured the cathodic behaviour of the hot electrode. Thermogalvanic corrosion of Alloy 31 in the LiBr solutions studied was not severe, although it negatively affects the corrosion resistance of the cold anode. The protective properties of the passive film formed on the anode surface were found to improve with thermogalvanic coupling time

Facile preparation of electrodes based on WO3 nanostructures modified with C and S used as anode materials for Li-ion batteries

[EN] An appropriate morphological and structure matrix configuration where lithium ions could insert and de-insert is essential for lithium-ion batteries (LiB). Tungsten oxides (WO3) are especially attractive materials for this aim. In this research, the effects of the morphology and composition of WO3 nanostructures on the charge/discharge behavior for Li-ion batteries are methodically examined. On the one hand, nanostructured WO3 thin film was effectively synthesized by an electrochemical procedure. Then, an annealing treatment at 600°C in air environment for 4 h was carried out. In the second electrode synthesized, a carbon layer was uniformly deposited on WO3 nanostructures to obtain a WO3/C electrode. Finally, WO3/WS2 electrodes were prepared by means of in situ sulfurization of WO3 one-step solid-state synthesis using tungsten trioxide (WO3) and thiourea as precursor material. By using X-ray photoelectron spectroscopy, X-ray diffraction analysis, transmission electron microscopy, Raman spectra, and field-emission scanning electron microscopy, the three electrodes have been morphologically characterized. Electrochemical properties were analyzed by cyclic voltammogram, galvanostatic charge/discharge cycling, and electrochemical impedance spectroscopy. Among all the synthesized samples, WO3/C nanostructures reveal the best performance as they exhibit the greatest discharge capacity and cycle performance (820 mA h g¿1).UPV for the concession of a postdoctoral, Grant/Award Number: PAID-10-21; Ministerio de Universidades for the concession of the predoctoral, Grant/Award Number: FPU19/02466; Comunitat Valenciana, Grant/Award Number: IDIFEDER/18/044Roselló-Márquez, G.; García-García, D.; Cifre-Herrando, M.; Blasco-Tamarit, E.; Garcia-Anton, J. (2023). Facile preparation of electrodes based on WO3 nanostructures modified with C and S used as anode materials for Li-ion batteries. Journal of the American Ceramic Society. 106(4):2550-2566. https://doi.org/10.1111/jace.1891025502566106

Cavitation corrosion and repassivation kinetics of titanium in a heavy brine LiBr solution evaluated by using electrochemical techniques and Confocal Laser Scanning Microscopy

The cavitation corrosion behaviour of commercially pure Grade 2 titanium in a 992 g/l LiBr solution has been investigated at 25 °C using an ultrasound device. Cavitation was found to have more influence on the anodic branch than on the cathodic branch, shifting the corrosion potential, Ecorr, and the OCP value towards more negative potentials, and increasing the corrosion current density, icorr, by six times. The repassivation kinetics of Grade 2 titanium have also been studied in the 992 g/l LiBr solution, at 25 °C and various applied potentials, using cavitation to damage the electrode surface. The repassivation kinetics have been analysed in terms of the current density flowing from the area damaged by cavitation, and the results were described by the equation i(t) = A·t−n. At potentials within the passive region, the passive film grew according to the high-field ion conduction model in which log i(t) is linearly proportional to 1/q(t). The damage generated during the potentiostatic tests has been quantified by means of Confocal Laser Scanning MicroscopyWe wish express our gratitude to the Ministerio de Ciencia e Innovacion (Project CTQ2009-07518), for the economical support of this research, to the Generalitat Valenciana for its help in the CLSM acquisition (MY08/ISIRYM/S/100), and to Dr. M. Asuncion Jaime for her translation assistance.Fernández Domene, RM.; Blasco Tamarit, ME.; García García, DM.; García Antón, J. (2011). Cavitation corrosion and repassivation kinetics of titanium in a heavy brine LiBr solution evaluated by using electrochemical techniques and Confocal Laser Scanning Microscopy. Electrochimica Acta. 58:264-275. https://doi.org/10.1016/j.electacta.2011.09.034S2642755