Physical aging of shape memory polymers based upon epoxy-thiol “click” systems

© 2017. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/The physical aging behaviour of two epoxy-thiol shape memory polymers has been studied: diglycidyl ether of bisphenol-A cross-linked with pentaerythritol tetrakis, denoted 4-thiol, with a calorimetric glass transition temperature, Tg, of 51 °C; and the same system modified with tri (2,3-epoxypropyl)isocyanurate in a 30 wt% proportion, denoted 4-thiol-30%iso, with Tg = 63 °C. The aging of both polymers has been measured by torsional creep for aging temperatures between room temperature and the Tg of each polymer. The creep behaviour of each polymer is characterised by a discrete distribution of relaxation times, which shifts with aging time according to a double logarithmic aging rate, µ, and with aging temperature according to an activation energy. The distribution of creep relaxation times for 4-thiol is rather symmetrical, and slightly narrower than that for 4-thiol-30%iso, which is also skewed to longer times. The dependence of µ on temperature displays a peak as the aging temperature reduces below Tg, and is sharper for 4-thiol, in accordance with the narrower distribution, as predicted by a theoretical model based upon structural relaxation kinetics. The other parameters defining the aging behaviour, namely the reduced activation energy (¿h*/R = 92 kK for 4-thiol and 82 kK for 4-thiol-30%iso) and the non-linearity parameter of structural relaxation (x = 0.35 for 4-thiol and 0.25 for 4-thiol-30%iso), have been determined experimentally and are compared with the predictions of the theoretical model. These parameters can be used to predict the effects of physical aging on the shape memory response.Peer ReviewedPostprint (author's final draft

AGROTECH09: building agricultural robots with lego mindstorm. A multidisciplinary and multicultural approach

This activity has been designed in the context of an innovation project devoted to the coordination on mathematical, physical, and engineering contents for a transversal path on mechatronics, automated control and information and communication technologies (from now onwards AGROMECATIC) at agricultural engineering studies in the Technical University of Madrid. One of the main tasks has consisted on setting up a new subject, robotics in agriculture (equivalent to 7 ECTS), which is used as a platform to test the abilities of the students to apply various aspects of the knowledge gathered along the previous 4 years on agricultural engineering, with special emphasis on. The students are demanded to build a variety of basic mechanisms into an autonomous vehicle capable of performing user defined general and specific agricultural tasks (such as selective harvest, transport, loading and unloading of product). The robot is programmed using object oriented language (LEJOS, JAVA for LEGO) and has to cover a variety of behaviors: navigation, exploration, and previous defined agricultural tasks. As a mean to test the skills developed by the students and to reinforce the multidisciplinary nature of AGROMECATICS, a European contest: AGROTECH09 has been settled, which is co-organized by BEST (Board of European Students of Technology). The activity will take place between the 11 th and 14 th of May at ETSI Agrónomos and recognizes up to 2 ECTS of individual dedication. 40 students from 16 countries with large variability of backgrounds: computers science, agronomy, engineering, physics, tele-communication will work jointly to solve a challenge which will be public on the 11 th of May with all materials being provided by the organization

Fitting into their shoes: how robots help multidisciplinary approaches under cooperative learning

La enseñanza de ingeniería agronómica está poblada de asignaturas con contenidos altamente específicos pertenecientes a distintas ramas del saber que raramente se integran entre sí de manera profunda. En los últimos años de carrera resulta interesante plantear como reto a los alumnos la posibilidad de poner a prueba los conocimientos adquiridos en agronomía, física, matemáticas e ingeniería en el desarrollo de un robot capaz de realizar una variedad de tareas agrícolas. Este es el marco en el que se ha impartido por primera vez la asignatura Robótica Aplicada a la Agricultura, la adquisición de las competencias necesarias y la discusión de los resultados de aprendizaje son los aspectos que se desarrollan en este trabajo desde la perspectiva de los alumnos que han participado. Metidos en los zapatos de los alumnos

Honeycomb monolithic design to enhance the performance of Ni-based catalysts for dry reforming of methane

Supported Ni catalysts (4,5% wt%) using a Ce-Zr oxide (18/82 molar ratio and a ceria rich surface) depicting advanced redox properties, were deposited by washcoating over cordierite honeycombs (230 and 400 cpsi). FIB-STEM unveiled nanostructure details otherwise undistinguishable by conventional techniques. The catalytic performance was evaluated in the dry reforming of methane al 700-900 degree C, using a CH4:CO2 1:1 feddstock, and exploring high Weight Hourly Space Velocity (115-346 L.g-1.h-1). The structured catalyts exhibited better performance than the corresponding powers, reaching values close to rhermodynamics limits for booth reactants conversion and H2/CO ratio, from 750 dgree C, and no deactivation was observed in prolongued experiments (24-48 h). This was related to both the high catalytic efficiency after being deposited with low loading on the cordierite and the intrinsic advantages of the monolithic reactor, like preventing from the kinetic control that operates in powdered samples under high WHSV or limiting the deactivation.Comment: 10 pages, 8 figures, 3 tables, 61 reference

Effects of heavy resistance training on maximal and explosive force production, endurance and serum hormones in adolescent handball players

Abstract To determine the eects of 6-weeks of heavyresistance training on physical ®tness and serum hormone status in adolescents (range 14±16 years old) 19 male handball players were divided into two dierent groups: a handball training group (NST, n = 10), and a handball and heavy-resistance strength training group (ST, n = 9). A third group of 4 handball goalkeepers of similar age served as a control group (C, n = 4). After the 6-week training period, the ST group showed an improvement in maximal dynamic strength of the leg extensors (12.2%; P < 0.01) and the upper extremity muscles (23%; P < 0.01), while no changes were observed in the NST and C groups. Similar dierences were observed in the maximal isometric unilateral leg extension forces. The height of the vertical jump increased in the NST group from 29.5 (SD 4) cm to 31.4 (SD 5) cm (P < 0.05) while no changes were observed in the ST and C groups. A signi®cant increase was observed in the ST group in the velocity of the throwing test [from 71.7 (SD 7) km á h A1 to 74.0 (SD 7) km á h A1 ; P < 0.001] during the 6-week period while no changes were observed in the NST and C groups. During a submaximal endurance test running at 11 km á h A1 , a signi®cant decrease in blood lactate concentration occurred in the NST group [from 3.3 (SD 0.9) mmol á l A1 to 2.4 (SD 0.8) mmol á l A1 ; P < 0.01] during the experiment, while no change was observed in the ST or C groups. Finally, a signi®cant increase (P < 0.01) was noted in the testosterone:cortisol ratio in the C group, while the increase in the NST group approached statistical signi®cance (P < 0.08) and no changes in this ratio occurred in the ST group. The present ®ndings suggested that the addition of 6-weeks of heavy resistance training to the handball training resulted in gains in maximal strength and throwing velocity but it compromised gains in leg explosive force production and endurance running. The tendency for a compromised testosterone:cortisol ratio observed in the ST group could have been associated with a state of overreaching or overtraining

The last deglaciation in the Picos de Europa National Park (Cantabrian Mountains, northern Spain)

42 páginas, 8 figuras, 4 tablas.-- El PDF del artículo esta en formato pre-print.A sedimentological and geochemical study of the Lago Enol sequence (Cantabrian Mountains, northern Spain), together with detailed geomorphological mapping, provides a first record of glacier evolution and climate change over the last 40 ka in the Picos de Europa National Park. The Enol glacier retreated from its maximum extent prior to 40 ka BP as demonstrated by the onset of proglacial lacustrine sedimentation in two glaciated depressions: the Comella hollow to the north (before 40 ka BP) and the Lago Enol (before 38 ka BP). These results support previous evidence that the maximum extent of southern European glaciers occurred earlier than in northern Europe. Alternation of homogeneous and laminated proglacial sediments during the glacier retreat illustrate a dynamic glacial evolution during the Marine Isotope Stage (MIS) 3 (40–26 ka BP). A slight warming is detected at 26 ka ago with the change from proglacial sediments (in a lake located in contact to the glacier) to glaciolacustrine sedimentation (in a non-contact or distal lake). Finally, the onset of organic-rich sediments took place at 18 ka ago. This last transition occurred in two phases, similarly to the North Atlantic Last Termination, suggesting a link between North Atlantic Deep Water formation oscillations and palaeohydrological variability in the Cantabrian Mountains.This research has been funded through the projects LIMNOCLIBER (REN2003-09130-C02-02), IBERLIMNO (CGL2005-20236-E/CLI), LIMNOCAL (CGL2006-13327-C04-01) and GRACCIE (CSD2007-00067), provided by the Spanish Inter-Ministry Commission of Science and Technology (CICYT). Additional funding was provided by the Spanish National Parks Agency through the project ‘Evolución climática y ambiental del Parque Nacional de Picos de Europa desde el último máximo glaciar – ref: 53/2006’. A. Moreno acknowledges funding from the European Commission's Sixth Framework Program (Marie Curie Outgoing International Fellowships, proposal 021673-IBERABRUPT).Peer reviewe

TWEAK Activates the Non-Canonical NFκB Pathway in Murine Renal Tubular Cells: Modulation of CCL21

TWEAK is a member of the TNF superfamily of cytokines that contribute to kidney tubulointerstitial injury. It has previously been reported that TWEAK induces transient nuclear translocation of RelA and expression of RelA-dependent cytokines in renal tubular cells. Additionally, TWEAK induced long-lasting NFκB activation suggestive of engagement of the non-canonical NFκB pathway. We now explore TWEAK-induced activation of NFκB2 and RelB, as well as expression of CCL21, a T-cell chemotactic factor, in cultured murine tubular epithelial cells and in healthy kidneys in vivo. In cultured tubular cells, TWEAK and TNFα activated different DNA-binding NFκB complexes. TWEAK-induced sustained NFκB activation was associated with NFκB2 p100 processing to p52 via proteasome and nuclear translocation and DNA-binding of p52 and RelB. TWEAK, but not TNFα used as control), induced a delayed increase in CCL21a mRNA (3.5±1.22-fold over control) and CCL21 protein (2.5±0.8-fold over control), which was prevented by inhibition of the proteasome, or siRNA targeting of NIK or RelB, but not by RelA inhibition with parthenolide. A second NFκB2-dependent chemokine, CCL19, was upregulates by TWEAK, but not by TNFα. However, both cytokines promoted chemokine RANTES expression (3-fold mRNA at 24 h). In vivo, TWEAK induced nuclear NFκB2 and RelB translocation and CCL21a mRNA (1.5±0.3-fold over control) and CCL21 protein (1.6±0.5-fold over control) expression in normal kidney. Increased tubular nuclear RelB and tubular CCL21 expression in acute kidney injury were decreased by neutralization (2±0.9 vs 1.3±0.6-fold over healthy control) or deficiency of TWEAK (2±0.9 vs 0.8±0.6-fold over healthy control). Moreover, anti-TWEAK treatment prevented the recruitment of T cells to the kidney in this model (4.1±1.4 vs 1.8±1-fold over healthy control). Our results thus identify TWEAK as a regulator of non-canonical NFκB activation and CCL21 expression in tubular cells thus promoting lymphocyte recruitment to the kidney during acute injury

Multidisciplinary exercises: coordination practices and applications from fundamental to applied subjects in agriculture engineering

This activity is carried out in the framework of an innovation project, whose main objective is to coordinate mathematical, physical and engineering contents for a transversal educational path focused on mechatronics, automated control and information and communication technologies. In such sense one important task in this project is the elaboration of practices and joint applications which will be proposed to the students in successive matters upon different points of view: “Common Practices”. Through this activity students will be guided to establish relationships between their scientific basic training and their technological formation. The students will work on the same example during different academic years and semesters using common materials and working spaces. The whole experience will be displayed in Moodle, a virtual learning environment. A preliminary proposal of “Common practice” is presented in this paper as one example: “Design and Analysis of Suspensions Systems for Stabilizing the Roll of Spray Booms”. In this example students of different academic levels are asked to solve the complexity of the problem along different subjects: Field measurements (analysis of variability on chemical applications using a spray boom) will be realized in the Agriculture Machinery topic - equivalent to 4.5 ECTS -. Analytical models for the analysis of different suspension systems in the Mechanics and Mechanisms topic -4.5 ECTS -. In Agriculture Applied Electronics – 2.5 ECTS – sensors and actuators will be studied to design controllers. Control strategies for damping the resonance frequency of the suspension will be studied in Process Simulation and Optimization – 3.5 ECTS –. And, finally, the design and development of a vehicle with a spray bar and the corresponding suspension systems will be done in the Robotics topic – 7 ECTS –

Análisis de la producción científica del Sistema Sanitario Público de Andalucía

YesEn 2008, se introducen por primera vez indicadores de actividad científica dentro de los objetivos de investigación, y se encomienda a la BV-SSPA la recopilación, análisis y evaluación de la producción científica con visibilidad internacional de los profesionales del SSPA. Impactia se desarrolla para dar una respuesta inmediata y automatizada a las necesidades de información que tienen los gerentes sobre la actividad científica de su centro. Permite además analizar la actividad científica que se contempla en los objetivos del Contrato Programa y en el plan de I+D+i y realizar detallados estudios bibliométricos. Utilizando Impactia se ha llevado a cabo el análisis, la descripción y el seguimiento de la producción científica del Sistema Sanitario Público de Andalucía, estimado a través de sus publicaciones científicas con visibilidad internacional, recogidas en las principales bases de datos bibliográficas, con la finalidad de conocer el volumen, la estructura y dinámica de la actividad científica desarrollada en un periodo determinado y su evolución a lo largo del tiempo