Electrochemical and photo-electrochemical processes of Methylene blue oxidation by Ti/TiO2 electrodes modified with Fe-allophane

Indexación: Scopus.This work reports the degradation of methylene blue (MB) on Ti/TiO2 and Ti/TiO2/Fe-allophane electrodes in a pH 3 using 0.1 M Na2SO4 as support electrolyte. SEM micrographs show a homogeneous distribution of TiO2 over the whole electrode surface forming nanotubes and nanopores. Fe-allophane modified electrode shows the formation of large-grains agglomerate on the electrode surface due to allophane, which provides a greater surface area to the electrode due to meso and micropore structures. Preliminary cyclic voltammetry show that Ti/TiO2 has the typical voltammetric response due to Ti(III)/Ti(IV) pair. Diffusional problems were observed through of the film when the electrode is modified with Fe-allophane modifying the quasi-reversible process Ti(III)/Ti(IV). Different kind of methodologies in the degradation process were used: Electrochemistry (EC), Photochemistry (PC), Photoelectrochemistry (PEC) and Adsorption (Ads). These methods were developing to discard any reaction or interaction that is not of interest. On Ti/TiO2 with PC and Ads methodologies was not observed any activity to MB degradation showing that is not photosensitive and that the interaction between this and surface electrode is low. But with EC and PEC degradation to 55% is reached after 3 hours of electrolysis. With Ti/TiO2-Fe-allophane electrodes are observed a higher activity for all methodologies. The PC and Ads methods show that the MB degradation reaches to ∼20 % of the initial concentration. As mentioned above, the PC and Ads processes no show degradation on Ti/TiO2, therefore the degradation it only due to the adsorption of MB in/on allophane coat behaving as concentrator matrix. A lower improvement is observed with EC process when is incorporated Ti/TiO2-Fe-allophane is due to the barrier of the electrode surface by oxidation products. With PEC is reached the higher degradation value of ∼88 %, showing an improvement of the degradation with the presence of Fe-allophane. The results indicate that the main role of Fe-allophane on the electrode is similar to a concentrator matrix.http://ref.scielo.org/shz7t

Segmentation and tracking of video objects for a content-based video indexing context

This paper examines the problem of segmentation and tracking of video objects for content-based information retrieval. Segmentation and tracking of video objects plays an important role in index creation and user request definition steps. The object is initially selected using a semi-automatic approach. For this purpose, a user-based selection is required to define roughly the object to be tracked. In this paper, we propose two different methods to allow an accurate contour definition from the user selection. The first one is based on an active contour model which progressively refines the selection by fitting the natural edges of the object while the second used a binary partition tree with aPeer ReviewedPostprint (published version

La concisión en la creación de informes: un caso práctico

Cinquenes Jornades de Foment de la Investigació de la FCHS (Any 1999-2000)Si bien la enseñanza del lenguaje escrito se apoya en diferentes características estilísticas como son brevedad, claridad, concisión y no-ambigüedad, más lo es cuando se trata de un documento empresarial escrito de carácter formal. A través de un estudio realizado con alumnos adultos de inglés empresarial, dirigido hacia la creación de informes empresariales basándose en la información oral recibida, analizamos en qué medida 2 grupos de alumnos de diferentes niveles reflejan cierto tipo de expresiones innecesarias para el contenido del texto, y de qué forma el nivel y la cantidad de información influyen en los resultados finales

La creación de informes como instrumento para el aprendizaje de una segunda lengua

Terceres Jornades de Foment de la Investigació de la FCHS (Any 1997-1998)La destreza de la escritura es uno de los aspectos que más relevancia adquiere en el aula de inglés para fines específicos. Siendo muchos y variados los documentos con los que se ejercita esta destreza dentro del aula, existe uno importante dentro del mundo empresarial y al cual se le ha prestado una menor atención como instrumento para la enseñanza de la expresión escrita en inglés. Hablamos del informe empresarial. Nuestro trabajo explica una experiencia llevada a cabo dentro de un aula de inglés empresarial, en la que se utiliza el informe empresarial como instrumento mediador en la enseñanza de la escritura en inglés. Queremos mostrar su uso en el aula, las diferencias observadas a partir de la comparación de dos grupos de sujetos de niveles distintos y los aspectos positivos que de este documento comercial se pueden obtener como partícipe en el proceso de enseñanza/ aprendizaje de una segunda lengua. Este estudio forma parte de una de las líneas de investigación abierta por el área de inglés para fines específicos, en concreto la referente a la síntesis de ideas y su expresión escrita en una segunda lengua

Countable covers and uniform closure

In this paper we present, in a unified way, several results af uniform approximation for real-valued continuous and uniformly continuous functions an a space X. We obtain all of them by applying a general method af proof that involves certain kind of cauntable covers af X, the so-called 2-finite covers. For instance, if X is endowed with the weak uniformity given by a vector lattice $\mathfrak{F}$ of real-valued functions an X containing all the real constant functions then, using that method, we characterize the uniform density of $\mathfrak{F}$ only in terms of the family $\mathfrak{F}$, improving a previous result in this line

Equalization in hard disk drive read channels

This paper presents a comprehensive non-exhaustive comparative study of hard disk drive read-channel equalization techniques used in the readback process of magnetically stored information. The main read channel architectures: partial-response maximum likelihood (PRML) and decision feedback equalization (DFE) based systems, are compared in power consumption, layout area, data signalling rate and data density. This work focuses on the key component of the read channel, presenting a continuous-time analog solution for the pulse-slimming equalizer capable of reducing power consumption and die area by a factor of ten, whilst showing equivalent response to a FIR filter implementation.info:eu-repo/semantics/acceptedVersio