Some indefinite nonlinear eigenvalue problems

In this work we study the structure of the set of positive solutions of a nonlinear eigenvalue problem with a weight changing sign. Specifically, the reaction term arises from a population dynamic model. We use mainly bifurcation methods to obtain our results

Configuración de fisuras en Y-FSZ

La microdureza Vickers de monocristales de 4.5 mol % de Y-PSZ ha sido estudiada hasta temperaturas de 1000QC. Se utilizaron dos clases de muestras: brutas de fabricación y sometidas a un tratamiento de recocido (envejecido) a 1600 "C durante 150 horas. Las partículas tetragonales se desarrollan en toda la muestra, alcanzan tamaños de hasta 1 micra durante el recocido y no se transforman en monoclínico durante el enfriamiento debido a que la temperatura de transformación (Ms) es inferior a la temperatura ambiente. Las indentaciones sobre planos (100) en muestras brutas de fabricación vienen acompañadas por fisuras para temperaturas menores de 600 "C. Por encima de esta temperatura la activación de dislocaciones se hace muy importante controlando el comportamiento mecánico del material. La fisuración es inexistente en muestras recocidas debido a la transformación tenaz

Uso de la espectroscopía Raman en la determinación de fases en Y-PSZ monocristalino

Se ha estudiado la estabilidad de la fase tetragonal en monocristales de Zr02 parcialmente estabilizados con 3,4; 4,7 y 6,3% mol de Y2O3 mediante espectroscopia Raman, tratados térmicamente a 1.600ºC hasta 1.000 horas. Estos resultados se han comparado con observaciones microestructurales realizadas mediante microscopía electrónica de transmisión, lo que ha permitido determinar el tiempo óptimo de envejecimiento y detectar el efecto debido al proceso de preparación de muestras.The phase stability of 3.4, 4.7, and 6.3% mol Y2O3 partially stabilized zirconia single crystals have been studied by Raman spectroscopy, with thermal treatment of length up to 1.000 hours. These results have been compared with the microstructural observations using transmission electron microscopy. This comparison has allowed us to determine the peakaged time for this alloy and the effect of sample preparation on the transformation

Generation of technology-portable flexible analog blocks

This paper introduces a complete methodology for retargeting of analog blocks to different sets of specifications, even to different technology processes. By careful integration of the tuning process of design parameters with layout generation, fully functional designs are generated in a few minutes of CPU time.Ministerio de Ciencia y Tecnología TIC 2001-092

General electrokinetic model for concentrated suspensions in aqueous electrolyte solutions: electrophoretic mobility and electrical conductivity in static electric fields

In recent years different electrokinetic cell models for concentrated colloidal suspensions in aqueous electrolyte solutions have been developed. They share some of its premises with the standard electrokinetic model for dilute colloidal suspensions, in particular, neglecting both the specific role of the so-called added counterions (i.e., those released by the particles to the solution as they get charged), and the realistic chemistry of the aqueous solution on such electrokinetic phenomena as electrophoresis and electrical conductivity. These assumptions, while having been accepted for dilute conditions (volume fractions of solids well below 1 %, say), are now questioned when dealing with concentrated suspensions. In this work, we present a general electrokinetic cell model for such kind of systems, including the mentioned effects, and we also carry out a comparative study with the standard treatment (the standard solution only contains the ions that one purposely adds, without ionic contributions from particle charging or water chemistry). We also consider an intermediate model that neglects the realistic aqueous chemistry of the solution but accounts for the correct contribution of the added counterions. The results show the limits of applicability of the classical assumptions and allow one to better understand the relative role of the added counterions and ions stemming from the electrolyte in a realistic aqueous solution, on electrokinetic properties. For example, at low salt concentrations the realistic effects of the aqueous solution are the dominant ones, while as salt concentration is increased, it is this that progressively takes the control of the electrokinetic response for low to moderate volume fractions. As expected, if the solids concentration is high enough the added counterions will play the dominant role (more important the higher the particle surface charge), no matter the salt concentration if it is not too high. We hope this work can help in setting up the real limits of applicability of the standard cell model for concentrated suspensions by a quantitative analysis of the different effects that have been classically disregarded, showing that in many cases they can be determinant to get rigorous predictions.Financial supports for this work by MICINN, Spain (projects FIS2010- 18972, FIS2013-47666-C3-1R, 2R, 3R) and Junta de Andalucía, Spain (project P2012-FQM-694), co-financed with FEDER (European Fund for Regional Development) funds by the EU

Emotional reactivity to binge food and erotic cues in women with bulimia nervosa symptoms

This work was supported by the MECD [grant numbers FPU16/01200], 'Doctoral College "Imaging the Mind" (FWF; W1233-B)', a grant from Junta de Andalucia, Spain [Grant Code P12.SEJ.391], and a grant from the Spanish Ministry of Economy and Competitiveness/MINECO (Grant Code: PSI2013-43777-P).Background: Studies on food cue reactivity have documented that altered responses to high-calorie food are associated with bulimic symptomatology, however, alterations in sexual motivations and behaviors are also associated clinical features in this population, which justify their inclusion as a research target. Here, we study responses to erotic cues—alongside food, neutral and aversive cues—to gain an understanding of specificity to food versus a generalized sensitivity to primary reinforcers. Methods: We recorded peripheral psychophysiological indices –the startle reflex, zygomaticus, and corrugator responses—and self-reported emotional responses (valence, arousal, and dominance) in 75 women completing the Bulimia Test-Revised (BULIT-R). Multiple regression analysis tested whether BULIT-R symptoms were predicted by selfreported and psychophysiological responses to food versus neutral and erotic versus neutral images. Results: The results showed that individuals with higher bulimic symptoms were characterized by potentiated eye blink startle response during binge food (vs. neutral images) and more positive valence ratings during erotic (vs. neutral) cues. Conclusions: The results highlight the negative emotional reactivity of individuals with elevated bulimic symptoms toward food cues, which could be related to the risk of progression to full bulimia nervosa and thereby addressed in prevention efforts. Results also point to the potential role of reactivity to erotic content, at least on a subjective level. Theoretical models of eating disorders should widen their conceptual scope to consider reactivity to a broader spectrum of primary reinforcers, which would have implications for cue exposure-based treatments. Plain English summary: We examined appetitive and aversive cue responses in college women to investigate how bulimic symptoms relate to primary reinforcers such as food and erotic images. We recorded peripheral psychophysiological indices (the startle reflex, zygomaticus, and corrugator responses) and self-reported emotional responses (valence, arousal, and dominance) in 75 college women that were presented with the Spanish version of the Bulimia Test-Revised. The results showed that bulimic symptoms increase both psychophysiological defensiveness toward food cues and subjective pleasure toward erotic cues. The findings suggest a generalized sensitivity to primary reinforcers in the presence of bulimic symptoms, and emphasize the relevance of adopting a wider framework in research and treatment on bulimia nervosa.MECD FPU16/01200Doctoral College "Imaging the Mind" (FWF) W1233-BJunta de Andalucia European Commission P12.SEJ.391Spanish Ministry of Economy and Competitiveness/MINECO PSI2013-43777-

Maghemite nanofluid based on natural ester: cooling and insulation properties assessment

The objective of this work is to study the effect that the addition of magnetic nanoparticles to a natural ester has on its properties and its cooling capacity. Some samples of ferrofluid (natural ester with maghemite) have been prepared using different concentrations. These have been characterized by measuring their thermo-hydraulic and dielectric properties, to find an optimal concentration. Then, the cooling capacities of the optimal nanofluid and the base fluid have been tested in a transformer immersed in these liquids. The experimental platform allowed the measurement of temperatures in different locations at different load levels. Parallel simulations of these tests have been carried out with a Computational Fluid Dynamics model of the experimental platform. The results show an improvement of the insulating capacity of the base fluid with the addition of maghemite nanoparticles, and an enhanced cooling capacity.This work was supported in part by the European Union’s Horizon 2020 Research and Innovation Programme through the Marie Sklodowska-Curie under Grant 823969, and in part by the Ministry of Economy through the National Research Project: Improvement of Insulation Systems of Transformers through Dielectric Nanofluids under Grant DPI2015-71219-C2 1-R. The work of C. Olmo was supported by the University of Cantabria and the Government of Cantabria through Ph.D. Scholarship under Grant CVE-2016-6626