Experimental study on the thermal control of a roof-top collective building antenna using a porous matrix filled with Water-Copper nanofluid

This experimental work addressed the thermal control a roof-top collective building antenna meant to control home equipment in smart buildings. The antenna was placed inside a concentric quasi-cylindrical cavity maintained at low temperature. Cooling was provided by a Water-Copper nanofluid saturated porous matrix placed between the antenna and the enclosure. The ratio of the thermal conductivity of the porous material to that of the water varied from 4 up to 41.2. The nanoparticles volume fraction varied between 0% and 5%. The main result was a new semi-empirical correlation that allows for the determination of the antenna's average surface temperature as a function of the governing parameters: ratios of nanofluid to water and porous media to water thermal conductivities, nanoparticles volume fraction, and Rayleigh number. The applicability of the correlation was illustrated for a practical application case. It was found that, for some cases, the proposed thermal control system improves power dissipation by a factor of 33% as compared with the case of pure water (2 kW versus 1.5 kW).Partial funding for open access charge: Universidade de Vigo/CISUG

Nonequilibrium Probabilistic Dynamics of the Logistic Map at the Edge of Chaos

We consider nonequilibrium probabilistic dynamics in logistic-like maps $x_{t+1}=1-a|x_t|^z$, $(z>1)$ at their chaos threshold: We first introduce many initial conditions within one among $W>>1$ intervals partitioning the phase space and focus on the unique value $q_{sen}<1$ for which the entropic form $S_q \equiv \frac{1-\sum_{i=1}^{W} p_i^q}{q-1}$ {\it linearly} increases with time. We then verify that $S_{q_{sen}}(t) - S_{q_{sen}}(\infty)$ vanishes like $t^{-1/[q_{rel}(W)-1]}$ [$q_{rel}(W)>1$]. We finally exhibit a new finite-size scaling, $q_{rel}(\infty) - q_{rel}(W) \propto W^{-|q_{sen}|}$. This establishes quantitatively, for the first time, a long pursued relation between sensitivity to the initial conditions and relaxation, concepts which play central roles in nonextensive statistical mechanics.Comment: Final version with new Title and small modifications. REVTeX, 8 pages and 4 eps figure

Extinction procedure induces pruning of dendritic spines in CA1 hippocampal field depending on strength of training in rats

Numerous reports indicate that learning and memory of conditioned responses are accompanied by genesis of dendritic spines in the hippocampus, although there is a conspicuous lack of information regarding spine modifications after behavioral extinction. There is ample evidence that treatments that typically produce amnesia become innocuous when animals are submitted to a procedure of enhanced training. We now report that extinction of inhibitory avoidance (IA), trained with relatively low foot-shock intensities, induces pruning of dendritic spines along the length of the apical dendrites of hippocampal CA1 neurons. When animals are trained with a relatively high foot-shock there is a high resistance to extinction, and pruning in the proximal and medial segments of the apical dendrite are seen, while spine count in the distal dendrite remains normal. These results indicate that pruning is involved in behavioral extinction, while maintenance of spines is a probable mechanism that mediates the protecting effect against amnesic treatments produced by enhanced training

Comparación analítica de dos consolidantes comerciales aplicados en areniscas eocenas de monumentos de los siglos XVI y XIX en San Sebastián (norte de España)

The conservation of buildings in the Basque Country made of Eocene sandstone is somewhat problematical, because this type of rock is relatively unstable. This instability is due to the variable content of carbonate cement (0-28%) and the presence of K-feldspar grains (1-13%) which appear to have been dissolved by both diagenetic and environmental processes. We have compared the results of the application of two commercial consolidating products: Sicof SM 296 (product A) and Consistone FS-hA (product B), both ethylsilicates, on Eocene sandstones of the Oquendo Admiral House (16th century) and the Gipuzkoa Provincial Government Palace (19th century), which are both located in the city of San Sebastián (Province of Gipuzkoa, Basque Country, Northern Spain). On the basis of different chemical and physical laboratory tests, together with Scanning Electron Microscopy (SEM) analysis, product A seems to be more efficient in consolidating such Eocene sandstone materials, since it penetrates into the first 8 mm of the rock, occupies very homogeneously even the smallest pore spaces and leaves a certain degree of remaining porosity which allows ventilation of the rock. In contrast, product B seems to be more appropriate for larger pore-sized rocks, because it only penetrates into the first 3 mm of the Eocene sandstone samples due to the thin pores of the matter. Our results demonstrate that the suitability of a commercial product depends not only on its own chemical composition, but also on the textural and lithological features of the rock material upon which it is to be applied.La conservación de los edificios del País Vasco construidos con areniscas del Eoceno es problemática porque este tipo de roca es relativamente inestable debido a su contenido variable en cemento carbonatado (0-28%) y a la presencia de granos de feldespato potásico (1-13%) disueltos tanto por procesos diagenéticos como ambientales. Hemos aplicado dos consolidantes comerciales: Sicof SM 296 (producto A) y Consistone FS+A (producto B), ambos silicatos de etilo, sobre las areniscas de la Casa del Almirante Oquendo (siglo XVI) y el Palacio de la Diputación Foral de Gipuzkoa (siglo XIX), ambos edificios en San Sebastián (País Vasco, norte de España). Los diferentes ensayos físicos y químicos junto con las observaciones al microscopio electrónico de barrido (SEM) revelan que el producto A es más eficiente para la consolidación de este tipo de areniscas, dado que penetra los primeros 8 mm de la roca, ocupa muy regularmente incluso los poros más pequeños y deja un cierto grado de porosidad remanente que permite la aireación de la roca. Por el contrario, el producto B parece más adecuado para rocas con mayor tamaño de poro, dado que sólo penetra los primeros 3 mm. Con ello, queda claro que la eficiencia de un consolidante comercial depende no sólo de su composición química, sino, en gran medida, de las características texturales y litológicas de la roca sobre la que se va a aplicar

D-π-A compounds with tunable intramolecular charge transfer achieved by incorporation of butenolide nitriles as acceptor moieties

Chromophores where a polyenic spacer separates a 4H-pyranylidene or benzothiazolylidene donor and three different butenolide nitriles have been synthesized and characterized. The role of 2(5H)-furanones as acceptor units on the polarization and the second-order nonlinear (NLO) properties has been studied. Thus, their incorporation gives rise to moderately polarized structures with NLO responses that compare favorably to those of related compounds featuring more efficient electron-withdrawing moieties. Derivatives of the proaromatic butenolide PhFu show the best nonlinearities. Benzothiazolylidene-containing chromophores present less alternated structures than their pyranylidene analogues, and, unlike most merocyanines, the degree of charge transfer does not decrease on lengthening the π-bridge.Financial support from MICINN-FEDER (CTQ2011-22727 and MAT2011-27978- C02-02), MINECO (CTQ2014-52331R), and Gobierno de Aragon-Fondo Social Europeo (E39 and E04) is gratefully acknowledged. Research at the Universidad de Malaga was supported by MINECO (CTQ2012-33733) and Junta de Andalucıa (P09-4708).Peer Reviewe

Spherical silicon photonic microcavities: From amorphous to polycrystalline

[EN] Shaping silicon as a spherical object is not an obvious task, especially when the object size is in the micrometer range. This has the important consequence of transforming bare silicon material in a microcavity, so it is able to confine light efficiently. Here, we have explored the inside volume of such microcavities, both in their amorphous and in their polycrystalline versions. The synthesis method, which is based on chemical vapor deposition, causes amorphous microspheres to have a high content of hydrogen that produces an onionlike distributed porous core when the microspheres are crystallized by a fast annealing regime. This substantially influences the resonant modes. However, a slow crystallization regime does not yield pores, and produces higher-quality-factor resonances that could be fitted to the Mie theory. This allows the establishment of a procedure for obtaining size calibration standards with relative errors of the order of 0.1%.This work was supported by Projects ENE2013-49987-EXP, MAT2012-35040, and MAT2015-69669-P of the Spanish Ministry of Economy and Competitiveness, and Project PROMETEOII/2014/026 of the Regional Valencian Government. The authors greatly acknowledge the Electron Microscopy Service of the UPV for their valuable help in the structural characterization of the microspheres.Fenollosa Esteve, R.; Garín Escrivá, M.; Meseguer Rico, FJ. (2016). Spherical silicon photonic microcavities: From amorphous to polycrystalline. Physical review B: Condensed matter and materials physics. 93(23):235307-1-235307-8. https://doi.org/10.1103/PhysRevB.93.235307S235307-1235307-8932

Longitud de rugosidad para el calor en condiciones de estabilidad atmosférica

Los coeficientes "volumétricos" de transporte para el calor dependen de la longitud de rugosidad respectiva. Esta longitud está definida como la altura en qué la temperatura del aire adquiere el mismo valor que la de superficie terrestre cuando el perfil térmico vertical es extrapolado hacia niveles inferiores. El proceso que condiciona esta altura es fundamentalmente de origen molecular. En este trabajo, en base a distintas ecuaciones, se estiman las longitudes de rugosidad para el calor en diferentes condiciones de estabilidad atmosférica utilizando los datos observacionales del Project Prairie Grass llevado a cabo en O'Neill, Nebraska (EEUU) en 1958. Se encuentra la relación entre esta longitud y el parámetro de estabilidad atmosférica de Monin-Obukhov, y se comparan los valores provenientes de la aplicación de las diferentes ecuaciones. Se encuentra que la longitud de rugosidad para el calor es potencialmente inversa al incremento de la estabilidad atmosférica.The volumetric coefficients for the trasportation of heat depend on the respective roughness length. This length is defined as the height in which air temperature reaches the same value as that of the surface when the vertical tempe rature profile is extrapolated to the lower levels. The process which conditions this height is mainly of molecular origin. In this paper, having as a base different equetions, we can estima te the roughness lengths for heat in different stable atmospheric conditions, using the observational facts (information) of the Pro ject Prairie Grass carried out in O’Neill, Nebraska (USA) in 1958. A functional relation is found between this length and the Monin - Obukhov atmospheric stability parameter and the values resulting from the application of the different equations are compared. it is then obtained that the roughness length for heat is potencia lly inverse to the increase of the atmospheric stability.Asociación Argentina de Geofísicos y Geodesta

New Adenovirus Groups in Western Palaearctic Bats

In the context of long-term screening for viruses on Western Palaearctic bats, we tested for the presence of adenovirus 1392 oropharyngeal swabs and 325 stool samples taken from 27 bat species. Adenoviruses were detected in 12 species of the Vespertilionidae and the Rhinolophidae families. Fifty positive respiratory and 26 positive stool samples were studied. Phylogenetic analyses of partial hexon protein and partial DNA-dependent DNA polymerase genes indicate that all these bat adenoviruses belong to the genus Mastadenovirus but without constituting a monophyletic cluster. According to genetic identities, the new groups are distinct to the previously described Bat mastadenovirus A and B species and contribute with potentially new members. Our data support that diversity of bat mastadenovirus is host-dependent and increase the knowledge of potentially pathogenic virus from bats. Due to the active role of bats as viral reservoirs, the characterization of these viruses is relevant for Public Health.This project was financially supported by an agreement between the Public Health Department of the Spanish Ministry of Health and the Instituto de Salud Carlos III for the development of "Rabies Surveillance in Spain" and by projects SAF 2006-12784-C02-01, SAF 2006-12784-C02-02, SAF 2009-09172 and SAF2013-47194-P of the General Research Programme of the Spanish Ministry of Science and Education

Sistema de emulación eólica para el ensayo de convertidores de baja potencia

En este trabajo se describe el diseño, desarrollo e implementación de un emulador de generadores eólicos de baja potencia, para analizar el comportamiento eléctrico de sistemas de aerogeneración frente a distintas condiciones de viento y carga. El mismo fue realizado en el marco del proyecto de investigación Energías Renovables en Redes Eléctricas Inteligentes que llevan a cabo en conjunto el Laboratorio de Instrumentación y Control (LIC) perteneciente al Dpto. de Ing. Electrónica, y el Laboratorio de Ensayos y Desarrollos Energéticos (LEyDE) perteneciente al Dpto. de Ing. Eléctrica, ambos de la Facultad de Ingeniería de la Universidad Nacional de Mar del Plata. El emulador instalado en el LEyDE consiste en un sistema de control de motor asincrónico basado en LabVIEW acoplado a un generador sincrónico de imanes permanentes, conectado a una instalación eléctrica de baja potencia que lleva la energía producida al LIC para ser inyectada a la red interna de la Facultad por medio de un inversor desarrollado en ese laboratorio. Luego de su implementación y prueba, se concluye que el mismo cumple con las condiciones de diseño de ambos laboratorios, resultando una herramienta flexible que puede ser reconfigurada para otros tipos de ensayos en el futuro.This work describes the design, development and implementation of a low-power experimental emulator of wind generators for the analysis of wind generation systems against different wind conditions, load variations and impulsive power perturbation. As is shown in this work the emulator aids in the research in the area of Renewable Energy and Smart Grid technologies, especially in the area of maximum power tracking (MPPT) algorithm development where different wind condition must be rehearsed under repetitive test conditions. The emulator consists of a voltagecontrolled asynchronous motor based on LabVIEW coupled to a synchronous permanent magnet generator whose three-phase output is fed into and current-controlled PWM grid-tie inverter connected to the electrical mains. The injected energy is current controlled by the PWM power converter also developed in a previous project in this laboratory. The emulator implementation was carried out using the joint efforts of the Control and Instrumentation Laboratory (LIC) belonging to the Electronics Engineering department and the Testing and Energy Developments Laboratory (LEyDE) of the electrical engineering department, both of the School of Engineering of the National University of Mar del Plata (UNMdP). After testing and implementation, we conclude that it complies with the conditions of design by both laboratories, resulting in a flexible tool that can be reconfigured for other types of trials in the future.Tema 8: Energías renovables, modelización y simulación.Facultad de Arquitectura y Urbanism