Jesús Alba Fernández

Acoustic characterization of recycled textile materials used as core elements in noise barriers

Studies on new acoustic eco-materials are gaining importance as there is an increasing understanding about the benefits of the use of environmentally friendly materials. In producing noise control elements it is not only important to recycle but also to manufacture devices with recycled content. A noise barrier is one of the most used devices to reduce high noise levels. For designing these devices, a sound absorbing material is very often used as the core of the barrier. The main goal of this work is the design and testing of novel green sound absorbingmaterials used as part of noise barriers. Recycled textile materials and nontoxic binder fibers were employed to manufacture the eco-materials studied in this research. Acoustic characterization of prototype noise barriers was carried out in a customdesigned small-scale reverberation chamber for the testing of small samples. Results showed that new materials used in noise barrier prototypes performed very well according to international standards, with performance comparable with those of commercially available noise barriers made of typical sound absorbing materials. These new materials could be part of noise reducing devices incorporating an environmentally conscious technology.

Effect of the estimation of the wall/floor junction type on the acoustic isolation

Deviations between the laboratory measurement and the final in situ measurement, are common in the acoustic isolation. A fundamental difference between both cases is the effect of the lateral flanks. This effect produce that the global acoustic insulation changes substantially. With the standard UNE‐EN‐12354‐1, it can be estimated the effect of the flank, obtaining the vibration reduction indexes and evaluating the insulation of every way. It is also possible to carried out a measurement procedure with the Standard ISO 10848, in it the index is measured and then the index is calculated. This paper shows the differences of results of airborne sound insulation and impact insulation with in situ measurements of the vibration reduction index and the different estimations that the Standard allow. Different unions are studied, and the influence of these in the global result of the insulation is evaluated.

Método de Agrupamiento en Línea para la Identificación de Modelos Borrosos Takagi-Sugeno

This paper presents a method for Takagi-Sugeno fuzzy modeling. This method updates on line both the structure and the parameters of the model by combining a new on line clustering algorithm with least squares techniques. The proposed clustering algorithm, that generates clusters that are used to form the fuzzy rule antecedents, is used for model structure identification. The update of consequent parameters is achieved by least squares estimators

Aplicando Flipped Teaching en Física del Grado en Ingenieria de Sistemas de Telecomunicación, Sonido e Imagen

Este trabajo se ha realizado gracias al apoyo del Vicerrectorado de Estudios, Calidad y Acreditacion de la UPV al Proyecto PIME 2016-2017 “Puesta en marcha de diversas experiencias con el enfoque Flipped Teaching en asignaturas de Matematicas y Fisica”.

Flipped Teaching en Física del Grado en Ingenieria de Sistemas de Telecomunicación, Sonido e Imagen: primeros resultados

Al “Grup d’Innovacion Educativa i Recerca en Materies Cientifiques (GIERMAC)”, se le ha concedido en octubre de 2015 el proyecto PIME-UPV, “Estudio sobre la aplicacion del Flip Teaching en asignaturas de Matematicas y Fisica”. El trabajo que se presenta relata una primera experiencia completa realizada con los alumnos de Fisica del Grado en Ingenieria de Sistemas de Telecomunicacion, Sonido e Imagen (GISTSI) durante los meses de noviembre y diciembre de 2015. En esta experiencia los alumnos se presentan de forma voluntaria a esta estrategia y son compensados con puntos adicionales por el esfuerzo. La experiencia esta centrada en temas de termodinamica, por lo que sera exportable a asignaturas de otras titulaciones que la impartan.

Aprendizaje basado en proyectos: Primera experiencia en la asignatura de Física del Grado en Ingeniería de Telecomunicación, Sonido e Imagen.

Esta comunicacion trata sobre la prueba de aplicacion del aprendizaje basado en proyectos en la asignatura de Fisica del Grado en Ingenieria de Telecomunicacion, Sonido e Imagen. Se realiza esta primera experiencia donde el ultimo bloque tematico dedicado al campo magnetico y a la induccion magnetica se articula en forma de proyectos que los alumnos eligen de forma voluntaria. En la comunicacion se resumen como se ha articulo esta metodologia activa, desde el contexto, objetivos, preguntas motrices, enunciado, planificacion, tipos de actividades, interdependencia, valoracion y conclusiones.

Experimental Investigation and Numerical Simulation of the Acoustic Waves Propagation in a Standing Wave Tube: Testing with a Sample of Rockwool

Characterization of sound-absorbing materials is one of the investigation fields that is acquiring most interest in the last few years. As a consequence, there is an increase in investigators who are trying to obtain mathematical models to predict the acoustical behavior of the materials, as well as those who are looking for new materials to improve the acoustic isolation and acoustic conditioning. There are lots of applications, such as mufflers used in engines, in which it is of great interest to know the velocity of sound waves and the pressure distribution inside ducts. In this paper, the numerical simulation technique based on the finite element method is applied to study the propagation of the plane acoustic waves inside a standing wave tube by means of the application of a harmonic analysis, studying the distribution of pressures in an established frequency range. ANSYS software has been used to compare the numerical results with the theoretical ones. Then, comparing the numerical results with the experimental ones, the validity of the experimental method is evaluated. The experimental method follows the Standard ISO 10534-2 that is used for the determination of the absorption coefficient and acoustic impedance in porous and fibrous materials.

Detección de puntos débiles de aislamiento acústico en edificación ya construida

Este trabajo ha sido financiado por el Ministerio de Educacion y Ciencia. DG RESEARCH (BIA2007-C02-01 y BIA2007-C02-02) y por el Ministerio de Ciencia e Innovacion (BIA2010-17723).

Nuevos materiales absorbentes acústicos basados en fibra de kenaf

This project has been funded by the Ministry of Education and Science. DG Research (BIA2007-C02-01 y BIA2007-C02-02).

A simple empirical model for recycled polyurethane foams for acoustical applications.

In this work, the acoustic behavior of recycled polyurethane foams is studied in the frequency domain. Other authors have described the behavior of porous materials based either on the flow resistance [Dunn & Davern] or the structural characteristics of the pores [Voronina]. The main objective of all these works has been the determination of the propagating constant and the characteristic impedance. Here, the propagating constant and the characteristic impedance are described as a function of the flow resistance. The flow resistance has been obtained from experimental measurements using the method proposed by Ingard & Dear. On the other hand, the normal incidence sound absorption coefficient values are obtained using the procedure described in the standard UNE‐EN ISO 10534‐2:2002. In this way, specific coefficients for recycled polyurethane foams are determined. These coefficients are later compared with the classical coefficients that describe the behavior of any open‐pore material.