Development of selected electro-active polymer-ceramic nanocomposites as pyroelectric thermal/infrared detector materials

The present work emphasises on the synthesis and characterization of electro-active polymer-ceramic nanocomposites which can be used for pyroelectric thermal/infrared detection applications. Two sets of samples belong to polymer-microcrystalline composites have also been investigated in the work. The polymers used in the work have been commercially available ones, but the nanoceramics have been synthesized following simple chemical routes and aqueous organic gel routes. After characterizing the nanoceramics for their structure by powder XRD, they have been dispersed in liquid polymer and sonicated for uniform dispersion. The viscous mixture so formed was cast in the form of films for experimentation. Samples with volume fraction of the ceramic phase varied from 0 to 0.25 have been prepared. Solution growth was followed to prepare microcrystalline samples for the polymer-microcrystalline composites. The physical properties that determine the pyroelectric sensitivity of a material are dielectric constant, dielectric loss, pyroelectric coefficient, thermal conductivity and specific heat capacity. These parameters have been determined for all the samples and compositions reported in this work.The pyroelectric figures of merit for all the samples were determined. The pyroelectric figures of merit that determine the pyroelectric sensitivity of a material are current sensitivity, voltage responsivity and detectivity. All these have been determined for each set of samples and reported in the thesis. In order to assess the flexibility and mouldability of the composites we have measured the Shore hardness of each of the composites by indentation technique and compared with the pyroelectric figures of merit. Some important factors considered during the material fabrication stages were maximum flexibility and maximum figures of merit for pyroelectric thermal/IR detection applications. In order to achieve these goals, all the samples are synthesized as composites of polymers and nano/microcrystalline particles and are prepared in the form of freestanding films. The selected polymer matrices and particle inclusions possess good pyroelectric coefficients, low thermal and dielectric properties, so that good pyroelectric figures of merit could be achieved. The salient features of the work include the particle size of the selected ceramic materials. Since they are in nanometer size it was possible to achieve high flexibility and moldability with high figures of merit for even low volume fractions of inclusions of the prepared nanocrystalline composites. In the case of microcrystalline TGS and DTGS, their composites in PU matrix protect them from fragility and humidity susceptibility and made them for environmental friendly applications.

El test Bender como detector de problemas emocionales y comportamentales en niños de cuarto y quinto de primaria

Determinar si el test de Bender puede discriminar, en niños de cuarto y quinto de primaria, problemas emocionales y comportamentales y poder establecer un diagnóstico diferencial. Los objetivos específicos se agrupan en tres bloques: 1.- El Test de Bender y variables sociodemográficos. 2.- El test de Bender como prueba madurativa. 3.- El test de Bender como técnica proyectiva. Con el fin de dar respuestas a los objetivos planteados se formula una serie de hipótesis que orientan el análisis de los resultados. Esta investigación consiste en un estudio descriptivo correlacional. Se realiza mediante la aplicación del test Gestáltico Visomotor de Bender. Se trata de una investigación básicamente descriptiva y correlacional, donde se han seleccionado sujetos de diferentes edades (9-11 años) evaluados en un solo momento temporal. Las variables que se han utilizado, se han clasificado en variables sociodemográificas y psicológicas. La población la componen los alumnos de cuarto y quinto de primaria de la población de Huelva, capital y provincia. La elección de los distintos colegios se ha realizado teniendo en cuenta el nivel socioeconómico y profesional de los padres. La muestra está constituida por 722 sujetos de los cuales el 49,8 por ciento corresponde a varones y el 50,1 por ciento a mujeres, escolarizado en colegios públicos y concertados pertenecientes a Huelva capital y periferia. La selección de los instrumentos de medida se establece el criterio de que sean técnicas fiables, asequibles y fáciles de aplicar : Prueba de maduración visomotora: Test Bender. Prueba de capacidad intelectual: Test de Factor 'G' de R. B. Cattell y A. K. S. Cattell (Escala 2, Forma A). Cuestionario de Personalidad para niños EPQ-J De H. J. Eysenck y S. B. G. Eysenck. Cuestionario de autoevaluación Ansiedad estado-rasgo en niños, de C. D. Spielberg et al. Cuestionario para el profesor tutor. El test de Bender se podría emplear como screening para detectar desajustes madurativos que pueden tener como consecuencias problemas emocionales y posibles conductas antisociales, pero no es válido para detectar patologías diferenciales como la ansiedad, neuroticismo y psicoticismo. Se puede considerar esta prueba como un complemento de las técnicas psicométricas y así proporcionar, no sólo una visión analítica, sino una perspectiva más global de la persona. Sin embargo, en la utilización del test de Bender como test de personalidad se deben tener en cuenta los siguientes planteamientos: a. Aplicarlo de forma individual. b. Conveniencia de tener una pequeña entrevista con el niño. c. Es aconsejable que el evaluador tenga experiencia en el manejo de pruebas proyectivas y amplios conocimientos de psicopatología infantil. d. Así mismo, es muy importante que el evaluador tenga cierto entrenamiento y experiencia con el test de Bender. Es importante seguir investigando los índices que se asocian a conductas disruptivas y asociales, pues parece que es donde se han obtenido más relaciones y quizás en un futuro pueda ser utilizada de manera preventiva.

Laser stripe peak detector for 3D scanners: a FIR filter approach

The accuracy of a 3D reconstruction using laser scanners is significantly determined by the detection of the laser stripe. Since the energy pattern of such a stripe corresponds to a Gaussian profile, it makes sense to detect the point of maximum light intensity (or peak) by computing the zero-crossing point of the first derivative of such Gaussian profile. However, because noise is present in every physical process, such as electronic image formation, it is not sensitive to perform the derivative of the image of the stripe in almost any situation, unless a previous filtering stage is done. Considering that stripe scanning is an inherently row-parallel process, every row of a given image must be processed independently in order to compute its corresponding peak position in the row. This paper reports on the use of digital filtering techniques in order to cope with the scanning of different surfaces with different optical properties and different noise levels, leading to the proposal of a more accurate numerical peak detector, even at very low signal-to-noise ratios

El detector de colors. 'El detector de colores'.

Resumen del vídeo en catalán

A muller galega no meio labrego. 'La mujer gallega en el ambiente rural'.

Ver la mujer a nivel general en todo el mundo. La mujer en el trabajo y la mujer en el medio social, cómo triunfa o cómo fracasa ante la presion ambiental. Comprobar, a continuación, a la mujer gallega en el trabajo. Cómo vive, cuáles son sus derechos y sus deberes. Y por último, qué es lo que dijo la mujer gallega. Mujeres de Galicia. Sondeo a través de cincuenta preguntas. Dibujos, láminas. La situación de la mujer en el mundo es resultado, en parte, querido por ella, en parte, provocado por la sociedad machista. Los movimientos de liberación de la mujer son formas poco válidas. Pues, la revolución de la mujer se tiene que hacer desde la universidad y por ella misma, aunque hoy por hoy lo tiene muy difícil.

Tecnología. Construcción de un detector de humedad.

En la cub.: Secundaria. Acompañado de : Tecnología. Estructura

Muller e traballo. 'Mujer y trabajo'.

Este material pretende ser una ayuda para que profesor@s y alumn@s de secundaria reflexionen sobre la actual situación de las mujeres trabajadoras y se pregunten sobre las posibles causas de la misma. Para ello hacen una breve panorámica de las trabajadoras en diferentes períodos históricos, presentando textos para trabajar en clase.

Mutational meltdown in primary endosymbionts: selection limits Muller's ratchet

Background Primary bacterial endosymbionts of insects (p-endosymbionts) are thought to be undergoing the process of Muller's ratchet where they accrue slightly deleterious mutations due to genetic drift in small populations with negligible recombination rates. If this process were to go unchecked over time, theory predicts mutational meltdown and eventual extinction. Although genome degradation is common among p-endosymbionts, we do not observe widespread p-endosymbiont extinction, suggesting that Muller's ratchet may be slowed or even stopped over time. For example, selection may act to slow the effects of Muller's ratchet by removing slightly deleterious mutations before they go to fixation thereby causing a decrease in nucleotide substitutions rates in older p-endosymbiont lineages. Methodology/Principal Findings To determine whether selection is slowing the effects of Muller's ratchet, we determined the age of the Candidatus Riesia/sucking louse assemblage and analyzed the nucleotide substitution rates of several p-endosymbiont lineages that differ in the length of time that they have been associated with their insect hosts. We find that Riesia is the youngest p-endosymbiont known to date, and has been associated with its louse hosts for only 13–25 My. Further, it is the fastest evolving p-endosymbiont with substitution rates of 19–34% per 50 My. When comparing Riesia to other insect p-endosymbionts, we find that nucleotide substitution rates decrease dramatically as the age of endosymbiosis increases. Conclusions/Significance A decrease in nucleotide substitution rates over time suggests that selection may be limiting the effects of Muller's ratchet by removing individuals with the highest mutational loads and decreasing the rate at which new mutations become fixed. This countering effect of selection could slow the overall rate of endosymbiont extinction.

A Packet/Frame sync detector based on statistical mode with application to wireless-USB

Wireless Personal Area Networks (WPANs) are offering high data rates suitable for interconnecting high bandwidth personal consumer devices (Wireless HD streaming, Wireless-USB and Bluetooth EDR). ECMA-368 is the Physical (PHY) and Media Access Control (MAC) backbone of many of these wireless devices. WPAN devices tend to operate in an ad-hoc based network and therefore it is important to successfully latch onto the network and become part of one of the available piconets. This paper presents a new algorithm for detecting the Packet/Fame Sync (PFS) signal in ECMA-368 to identify piconets and aid symbol timing. The algorithm is based on correlating the received PFS symbols with the expected locally stored symbols over the 24 or 12 PFS symbols, but selecting the likely TFC based on the highest statistical mode from the 24 or 12 best correlation results. The results are very favorable showing an improvement margin in the order of 11.5dB in reference sensitivity tests between the required performance using this algorithm and the performance of comparable systems.

A simple optimum detector for distributed space-time block coding under imperfect synchronisation

Most research on D-STBC has assumed that cooperative relay nodes are perfectly synchronised. Since such an assumption is difficult to achieve in many practical systems, this paper proposes a simple yet optimum detector for the case of two relay nodes, which proves to be much more robust against timing misalignment than the conventional STBC detector.

PIC detector for distributed space-time block coding under imperfect synchronisation

A parallel interference cancellation (PIC) detection scheme is proposed to suppress the impact of imperfect synchronisation. By treating as interference the extra components in the received signal caused by timing misalignment, the PIC detector not only offers much improved performance but also retains a low structural and computational complexity.

Image restoration for a rectangular poor-pixels detector

This paper presents a unique two-stage image restoration framework especially for further application of a novel rectangular poor-pixels detector, which, with properties of miniature size, light weight and low power consumption, has great value in the micro vision system. To meet the demand of fast processing, only a few measured images shifted up to subpixel level are needed to join the fusion operation, fewer than those required in traditional approaches. By maximum likelihood estimation with a least squares method, a preliminary restored image is linearly interpolated. After noise removal via Canny operator based level set evolution, the final high-quality restored image is achieved. Experimental results demonstrate effectiveness of the proposed framework. It is a sensible step towards subsequent image understanding and object identification.