Development of a genre-dependent TTS system with cross-speaker speaking-style transplantation

One of the biggest challenges in speech synthesis is the production of contextually-appropriate naturally sounding synthetic voices. This means that a Text-To-Speech system must be able to analyze a text beyond the sentence limits in order to select, or even modulate, the speaking style according to a broader context. Our current architecture is based on a two-step approach: text genre identification and speaking style synthesis according to the detected discourse genre. For the final implementation, a set of four genres and their corresponding speaking styles were considered: broadcast news, live sport commentaries, interviews and political speeches. In the final TTS evaluation, the four speaking styles were transplanted to the neutral voices of other speakers not included in the training database. When the transplanted styles were compared to the neutral voices, transplantation was significantly preferred and the similarity to the target speaker was as high as 78%.

Estudio de las distribuciones tensionales y de las resistencias de los rellenos de pasta de la mina subterránea de Aguas Teñidas (Huelva)

This thesis presents the study carried out at an underground mine to understand the stress distribution in the paste fills and to calculate the stability of the paste walls in the primary and secondary stopes. The mine is operated using sublevel stopes and fan blasting. The primary and secondary stopes are 20m wide, 30m high and between 20 and 60m long. Three-dimensional numerical models designed with the FLAC 3D software programme are used to study the distribution of the vertical stresses in the paste walls exposed in the primary and secondary stopes, and their evolution as the mining advance increases. The numerical models have demonstrated that an arc-like effect is produced in the paste fills of the primary stopes, that is, those which have either lateral walls in mineral or rock. This effect relieves the vertical stresses and increases the stability of the exposed paste wall fill. From the study, it is deduced that in this type of stope, the fill stability can be calculated using the formula established by Mitchell, (Mitchell, Olsen, and Smith 1982, 14-28). Based on the results of the numerical models, in the 30m high secondary stopes, the arc effect starts to be evident only in paste walls with a width/height ratio lower than 0.7. 3-D calculations show that the use of Mitchell formula may be risky when estimating the fill stability in secondary stopes. Therefore, in these cases, the traditional two-dimensional method for calculating the stability of vertical slopes on cohesive saturated soils in the short term should be used. However this method may give conservative results for paste walls in secondary stopes with a width/height ratio below 0.5. RESUMEN Esta Tesis presenta el estudio realizado en la mina subterránea de Aguas Teñidas (Huelva, España) para comprender la distribución de tensiones en los rellenos de pasta y calcular la estabilidad de las paredes de pasta en las cámaras primarias y secundarias. El método de explotación utilizado en esta mina es el de cámaras con subniveles y voladura en abanico. Las cámaras primarias y secundarias tienen una anchura de 20 m, una altura de 30 m y una longitud variable entre 20 y 60 m. Mediante modelos numéricos tridimensionales realizados con el programa FLAC 3D se ha estudiado la distribución de las tensiones verticales en las paredes de pasta que quedan expuestas en las cámaras primarias y secundarias, y su evolución a medida que aumenta la superficie explotada. La modelización numérica ha puesto de manifiesto que se produce efecto arco en los rellenos de pasta de las cámaras primarias, o sea, aquellas que tienen ambos hastiales en mineral o en roca. Este efecto aligera las tensiones verticales y aumenta la estabilidad del relleno de la pared de pasta expuesta. De acuerdo con los resultados de los modelos numéricos, en las cámaras secundarias de 30 m de alto, el efecto arco empieza a manifestarse solamente en las paredes de pasta de relación anchura/altura menor de 0,7. Los cálculos realizados en tres dimensiones indican que la fórmula de Mitchell (Mitchell, Olsen, y Smith 1982, 14-28) puede resultar arriesgada para estimar la estabilidad del relleno en este tipo de cámaras. Por consiguiente, se recomienda utilizar en estos casos el método que tradicionalmente se ha empleado para calcular la estabilidad de taludes verticales en suelos cohesivos a corto plazo, en dos dimensiones. Aunque este método puede resultar conservador para paredes de pasta de cámaras secundarias con una relación anchura/altura inferior a 0,5. Para usar relleno de pasta para el sostenimiento en minería subterránea hay que tener en cuenta el cálculo de los parámetros de diseño, optimización de la mezcla, cualidades de bombeo y la operación de transporte al interior de la mina. Los gastos de ésta operación minera son importantes ya que pueden representar hasta de 20%.

Multifunctional core–shell Co–SiO2 nanowires via electrodeposition and sol–gel techniques

In this work, we propose a new strategy for the synthesis of multifunctional nanowires using a combination of sol–gel and electrodeposition techniques, based on a two-step procedure. First of all, nanotubes of SiO2 are synthesized via a sol–gel technique using polycarbonate membranes as templates. Homogenous nanotubes are obtained after centrifugation and thermal annealing. Afterwards, a ferromagnetic cobalt core is grown using potentiostatic electrodeposition. Finally, the core–shell Co–SiO2 nanowires are released by dissolving the template using wet-etching. These nanodevices can be used for many detection and sensing purposes. As a proof of concept, we have developed a pH nanosensor by including a pH-sensitive organic dye in the SiO2 shell. The sensing principle is based on the optical response of the organic dye towards pH when added to a solution. The magnetic core allows the recovery of the nanosensors after use. These nanowires can therefore be used as recoverable pH nanosensors. By changing the dye molecule to another molecule or receptor, the procedure described in the paper can be used to synthesize nanodevices for many different applications.

Production of biodiesel from animal fat using supercritical ethanol

Biodiesel is currently produced from a catalytic transesterification reaction of various types of edible and non-edible oil with methanol. The use of waste animal tallow instead of edible oils opens a route to recycle this waste. This material has the advantage of lower costs but the problem of high content of free fatty acids, becoming necessary a pre-esterification reaction that increases the cost of the catalytic process. The production of biodiesel using supercritical alcohols is appropriate for materials with high acidity and water content, therefore the use of this process with animal fat is a promising alternative. Ethanol has been used because it can be produced from biomass via fermentation resulting in a complete renewable biodiesel, instead of methanol that derives from fossil feedstocks. Two different processes have been studied: first, the direct transesterification of animal fat using supercritical ethanol and second a two-step process where the first step is a hydrolysis of the animal fat and the second step is the esterification of the resulting fatty acids. The temperature, the molar ratio ethanol:fat and the time have been modified in the different reactions to study the effect in the final conversion and the degradation of the unsaturated fatty acid esters, main inconvenient of these high temperature and pressure processes.