Modelización del ruido transmitido por flancos en la edificación en nuevas soluciones constructivas

El ruido transmitido por flancos laterales en edificación es uno de los problemas importantes en su aislamiento acústico, por lo que es conveniente incorporar nuevas soluciones constructivas que permitan abrir el abanico de posibilidades. En este trabajo de Tesis se aborda ese problema. En primer lugar se realiza una revisión importante de técnicas y modelos de medición y predicción del comportamiento acústico de materiales que pudiesen ser susceptibles de usarse en edificación. En esta línea nos hemos centrado sobre todo en dos posibilidades: materiales para usarlos como absorbentes acústicos y materiales para utilizarlos como lámina elástica en un suelo flotante. Se han estudiado varios tipos de materiales, sobre todo materiales reciclados o de fibras naturales, de los que se han obtenido sus características necesarias para valorar si son absorbentes acústicos, e incluso se han obtenido modelos propios de nuevos materiales. También se estudian diferentes reciclados y láminas valorando si son eficientes en un suelo flotante. Se presenta, pues, un estudio de nuevos materiales para edificación que permita aumentar la variedad o que sirva para reutilizar o reciclar otros productos o deshechos. Además, todo esto, estudiando la incertidumbre del ensayo en cada caso. Otro bloque importante de la tesis lo conforma la puesta en marcha y validación de una técnica de medida "in situ" de las transmisiones laterales. Actualmente no existe ninguna técnica normalizada y sólo existen ensayos normalizados en laboratorio para ciertas soluciones constructivas. Se han medido cientos de configuraciones de uniones diferentes, combinando conexiones rígidas y elásticas de unión, y valorando también el efecto del suelo flotante. Se ha estudiado también la incertidumbre de este tipo de ensayos y en qué condiciones son válidos los resultados del ensayo. Con toda la información obtenida, se han obtenido algunas fórmulas ajustadas y diferentes conclusiones respecto a ciertas uniones.Rey Tormos, RMD. (2009). Modelización del ruido transmitido por flancos en la edificación en nuevas soluciones constructivas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6882Palanci

Medida de la temperatura con una botella

[EN] The purpose of this paper is the experimental determination of temperature using a bottle as the only means. The bottle is a resonator of Helmholtz, which is the acoustic simpler system. Its behavior depends directly on the speed of propagation of the sound in the air and. This speed depends on temperature. In this paper are proposed two different procedures to determine the temperature easily.[ES] El objeto de este trabajo es la determinación experimental de la temperatura utilizando como único medio una botella. La botella es un resonador de Helmholtz, que es el sistema acústico más sencillo. Su comportamiento depende directamente de la velocidad de propagación del sonido en el aire y ésta, a su vez, de la temperatura. Se proponen dos procedimientos diferentes que permiten obtener la temperatura de forma sencilla.Alba Fernández, J.; Rey Tormos, RMD. (2014). Medida de la temperatura con una botella. Revista de Acústica. 45(3-4):7-10. http://hdl.handle.net/10251/56783S710453-

Working on the Transversal Competence "Knowledge of contemporary problems" in the Master of Acoustic Engineering

[EN] The subject Building Acoustics, of the Master's Degree in Acoustic Engineering, of the Escola Politècnica Superior de Gandia, is checkpoint of the Transversal Competence “knowledge of contemporary problems” from five years ago. This paper shows how it has been the set up using technical reports, the decisions we have taken and approach, the materials developed and their evolution, the results obtained and conclusions. It is also presented a SWOT analysis about the acquisition of this competence.[ES] La asignatura Aislamiento Acústico en la Edificación, del Máster en Ingeniería Acústica, de la Escuela Politécnica Superior de Gandia, es punto de control de la Competencia Transversal “Conocimientos de problemas contemporáneos” desde hace seis años. En este trabajo se muestra cómo se ha puesto en marcha utilizando la redacción de informes técnicos, las decisiones tomadas y su enfoque, los materiales desarrollados y su evolución, los resultados obtenidos y conclusiones. Se presenta un análisis DAFO final sobre la adquisición de esta competencia.Alba Fernández, J.; Rey Tormos, RMD. (2022). Trabajando la Competencia Transversal “Conocimientos de problemas contemporáneos” en el Máster de Ingeniería Acústica. Editorial Universitat Politècnica de València. 348-359. https://doi.org/10.4995/INRED2022.2022.1589634835

Competencia transversal “Aprendizaje Permanente”: experiencia en la asignatura Transductores e Instrumentación Acústica

[EN] Lifelong learning is one of the transversal competences that the Polytechnic University of València aims to prove. The “Acoustic Transducers and Instrumentation” subject of Engineering Degree in Telecommunications Systems, Sound and Image degree is a checkpoint of that competence. During the 2015-2016 academic year some mechanisms have been put in place in order to work it in the subject and evaluate it. In this work the experience of this year is summarized, and strengths and weakness of the initial proposal are evaluated, thinking of further improvements.[ES] El aprendizaje permanente es una de las competencias transversales que la Universitat Politécnica de Valencia pretende acreditar. La asignatura “Transductores e Instrumentación Acústica” de la titulación del Grado en Ingeniería de Sistemas de Telecomunicación, Sonido e Imagen es punto de control de dicha competencia. En el curso 2015-2016 se han puesto en marcha mecanismos para trabajarla en la asignatura y para poder evaluarla. En este trabajo se resume la experiencia de este curso, y se valoran fortalezas y debilidades de la propuesta inicial, pensando en posibles mejoras para el próximo curso.Alba Fernández, J.; Rey Tormos, RMD. (2016). Competencia transversal “Aprendizaje Permanente”: experiencia en la asignatura Transductores e Instrumentación Acústica. En In-Red 2016. II Congreso nacional de innovación educativa y docencia en red. Editorial Universitat Politècnica de València. https://doi.org/10.4995/INRED2016.2016.436

Estrategia para evaluar la competencia transversal “Aprendizaje Permanente” en la asignatura Transductores e Instrumentación Acústica

[EN] Use the learning in a strategically, autonomously and flexibly way, throughout life, according to the pursued objective is one of the transversal competences that is control item of the subject entitled "Transducers and Acoustic Instrumentation". This subject belong to the Bachelor's Degree in Engineering of Telecommunications Systems, Sound and Image. During the 2015-2016 academic year, we have initiated and presented strategies for start up the mechanisms in order to work and evaluate this transversal competence. We have defined a number of improvements for the 2016-2017 academic year. These improvements have based on the results obtained during the 2015-2016 academic year. This paper shows the evolution and valuation of the last two academic years[ES] Utilizar el aprendizaje de manera estratégica, autónoma y flexible, a lo largo de toda la vida, en función del objetivo perseguido es una de las competencias transversales que es punto de control de la asignatura “Transductores e Instrumentación Acústica” de la titulación del Grado en Ingeniería de Sistemas de Telecomunicación, Sonido e Imagen. En el curso 2015-2016 se iniciaron y presentaron estrategias de puesta en marcha de mecanismos para trabajarla en la asignatura y evaluarla. En base a los resultados obtenidos se definieron una serie de mejoras para el curso 2016-2017. En este trabajo se muestra la evolución y valoración de los dos cursos.Alba Fernández, J.; Rey Tormos, RMD. (2017). Estrategia para evaluar la competencia transversal “Aprendizaje Permanente” en la asignatura Transductores e Instrumentación Acústica. En In-Red 2017. III Congreso Nacional de innovación educativa y de docencia en red. Editorial Universitat Politècnica de València. 1032-1043. https://doi.org/10.4995/INRED2017.2017.6859OCS1032104

Sound-Absorption Properties of Materials Made of Esparto Grass Fibers

[EN] Research on sound-absorbing materials made of natural fibers is an emerging area in sustainable materials. In this communication, the use of raw esparto grass as an environmentally friendly sound-absorbing material is explored. Measurements of the normal-incidence sound-absorption coefficient and airflow resistivity of three different types of esparto from different countries are presented. In addition, the best-fit coefficients for reasonable prediction of the sound-absorption performance by means of simple empirical formulae are reported. These formulae require only knowledge of the airflow resistivity of the fibrous material. The results presented in this paper are an addition to the characterization of available natural fibers to be used as alternatives to synthetic ones in the manufacturing of sound-absorbing materials.This research was funded by CONICYT-FONDECYT, grant number 1171110.Arenas, JP.; Rey Tormos, RMD.; Alba, J.; Oltra, R. (2020). Sound-Absorption Properties of Materials Made of Esparto Grass Fibers. Sustainability. 12(14):1-10. https://doi.org/10.3390/su12145533S1101214Faruk, O., Bledzki, A. K., Fink, H.-P., & Sain, M. (2012). Biocomposites reinforced with natural fibers: 2000–2010. Progress in Polymer Science, 37(11), 1552-1596. doi:10.1016/j.progpolymsci.2012.04.003Pickering, K. L., Efendy, M. G. A., & Le, T. M. (2016). A review of recent developments in natural fibre composites and their mechanical performance. Composites Part A: Applied Science and Manufacturing, 83, 98-112. doi:10.1016/j.compositesa.2015.08.038Asdrubali, F., Schiavoni, S., & Horoshenkov, K. V. (2012). A Review of Sustainable Materials for Acoustic Applications. Building Acoustics, 19(4), 283-311. doi:10.1260/1351-010x.19.4.283Berardi, U., & Iannace, G. (2015). Acoustic characterization of natural fibers for sound absorption applications. Building and Environment, 94, 840-852. doi:10.1016/j.buildenv.2015.05.029Koruk, H., & Genc, G. (2015). Investigation of the acoustic properties of bio luffa fiber and composite materials. Materials Letters, 157, 166-168. doi:10.1016/j.matlet.2015.05.071Ersoy, S., & Küçük, H. (2009). Investigation of industrial tea-leaf-fibre waste material for its sound absorption properties. Applied Acoustics, 70(1), 215-220. doi:10.1016/j.apacoust.2007.12.005Hosseini Fouladi, M., Nor, M. J. M., Ayub, M., & Leman, Z. A. (2010). Utilization of coir fiber in multilayer acoustic absorption panel. Applied Acoustics, 71(3), 241-249. doi:10.1016/j.apacoust.2009.09.003Hosseini Fouladi, M., Ayub, M., & Jailani Mohd Nor, M. (2011). Analysis of coir fiber acoustical characteristics. Applied Acoustics, 72(1), 35-42. doi:10.1016/j.apacoust.2010.09.007Ramis, J., Del Rey, R., Alba, J., Godinho, L., & Carbajo, J. (2014). A model for acoustic absorbent materials derived from coconut fiber. Materiales de Construcción, 64(313), e008. doi:10.3989/mc.2014.00513Oldham, D. J., Egan, C. A., & Cookson, R. D. (2011). Sustainable acoustic absorbers from the biomass. Applied Acoustics, 72(6), 350-363. doi:10.1016/j.apacoust.2010.12.009Yang, W., & Li, Y. (2012). Sound absorption performance of natural fibers and their composites. Science China Technological Sciences, 55(8), 2278-2283. doi:10.1007/s11431-012-4943-1Tang, X., Zhang, X., Zhang, H., Zhuang, X., & Yan, X. (2018). Corn husk for noise reduction: Robust acoustic absorption and reduced thickness. Applied Acoustics, 134, 60-68. doi:10.1016/j.apacoust.2018.01.012Berardi, U., Iannace, G., & Di Gabriele, M. (2017). The Acoustic Characterization of Broom Fibers. Journal of Natural Fibers, 14(6), 858-863. doi:10.1080/15440478.2017.1279995Lim, Z. Y., Putra, A., Nor, M. J. M., & Yaakob, M. Y. (2018). Sound absorption performance of natural kenaf fibres. Applied Acoustics, 130, 107-114. doi:10.1016/j.apacoust.2017.09.012Malawade, U. A., & Jadhav, M. G. (2020). Investigation of the Acoustic Performance of Bagasse. Journal of Materials Research and Technology, 9(1), 882-889. doi:10.1016/j.jmrt.2019.11.028Gomez, T. S., Navacerrada, M. A., Díaz, C., & Fernández-Morales, P. (2020). Fique fibres as a sustainable material for thermoacoustic conditioning. Applied Acoustics, 164, 107240. doi:10.1016/j.apacoust.2020.107240Othmani, C., Taktak, M., Zein, A., Hentati, T., Elnady, T., Fakhfakh, T., & Haddar, M. (2016). Experimental and theoretical investigation of the acoustic performance of sugarcane wastes based material. Applied Acoustics, 109, 90-96. doi:10.1016/j.apacoust.2016.02.005Or, K. H., Putra, A., & Selamat, M. Z. (2017). Oil palm empty fruit bunch fibres as sustainable acoustic absorber. Applied Acoustics, 119, 9-16. doi:10.1016/j.apacoust.2016.12.002Taban, E., Khavanin, A., Faridan, M., Samaei, S. E., Samimi, K., & Rashidi, R. (2019). Comparison of acoustic absorption characteristics of coir and date palm fibers: experimental and analytical study of green composites. International Journal of Environmental Science and Technology, 17(1), 39-48. doi:10.1007/s13762-019-02304-8Putra, A., Or, K. H., Selamat, M. Z., Nor, M. J. M., Hassan, M. H., & Prasetiyo, I. (2018). Sound absorption of extracted pineapple-leaf fibres. Applied Acoustics, 136, 9-15. doi:10.1016/j.apacoust.2018.01.029Yun, B. Y., Cho, H. M., Kim, Y. U., Lee, S. C., Berardi, U., & Kim, S. (2020). Circular reutilization of coffee waste for sound absorbing panels: A perspective on material recycling. Environmental Research, 184, 109281. doi:10.1016/j.envres.2020.109281Zhang, J., Shen, Y., Jiang, B., & Li, Y. (2018). Sound Absorption Characterization of Natural Materials and Sandwich Structure Composites. Aerospace, 5(3), 75. doi:10.3390/aerospace5030075Kusno, A., Sakagami, K., Okuzono, T., Toyoda, M., Otsuru, T., Mulyadi, R., & Kamil, K. (2019). A Pilot Study on the Sound Absorption Characteristics of Chicken Feathers as an Alternative Sustainable Acoustical Material. Sustainability, 11(5), 1476. doi:10.3390/su11051476Delany, M. E., & Bazley, E. N. (1970). Acoustical properties of fibrous absorbent materials. Applied Acoustics, 3(2), 105-116. doi:10.1016/0003-682x(70)90031-9Berardi, U., & Iannace, G. (2017). Predicting the sound absorption of natural materials: Best-fit inverse laws for the acoustic impedance and the propagation constant. Applied Acoustics, 115, 131-138. doi:10.1016/j.apacoust.2016.08.012Miki, Y. (1990). Acoustical properties of porous materials. Modifications of Delany-Bazley models. Journal of the Acoustical Society of Japan (E), 11(1), 19-24. doi:10.1250/ast.11.19Attenborough, K. (1982). Acoustical characteristics of porous materials. Physics Reports, 82(3), 179-227. doi:10.1016/0370-1573(82)90131-4Dunn, I. P., & Davern, W. A. (1986). Calculation of acoustic impedance of multi-layer absorbers. Applied Acoustics, 19(5), 321-334. doi:10.1016/0003-682x(86)90044-7Garai, M., & Pompoli, F. (2005). A simple empirical model of polyester fibre materials for acoustical applications. Applied Acoustics, 66(12), 1383-1398. doi:10.1016/j.apacoust.2005.04.008Rey, R. del, Alba, J., Arenas, J. P., & Sanchis, V. J. (2012). An empirical modelling of porous sound absorbing materials made of recycled foam. Applied Acoustics, 73(6-7), 604-609. doi:10.1016/j.apacoust.2011.12.009Arenas, J. P., Rebolledo, J., Del Rey, R., & Alba, J. (2014). Sound Absorption Properties of Unbleached Cellulose Loose-Fill Insulation Material. BioResources, 9(4). doi:10.15376/biores.9.4.6227-6240Silva, C. C. B. da, Terashima, F. J. H., Barbieri, N., & Lima, K. F. de. (2019). Sound absorption coefficient assessment of sisal, coconut husk and sugar cane fibers for low frequencies based on three different methods. Applied Acoustics, 156, 92-100. doi:10.1016/j.apacoust.2019.07.001Sair, S., Mansouri, S., Tanane, O., Abboud, Y., & El Bouari, A. (2019). Alfa fiber-polyurethane composite as a thermal and acoustic insulation material for building applications. SN Applied Sciences, 1(7). doi:10.1007/s42452-019-0685-zMaghchiche, A., Haouam, A., & Immirzi, B. (2013). Extraction and Characterization of Algerian Alfa Grass Short Fibers (Stipa Tenacissima). Chemistry & Chemical Technology, 7(3), 339-344. doi:10.23939/chcht07.03.339Nadji, H., Diouf, P. N., Benaboura, A., Bedard, Y., Riedl, B., & Stevanovic, T. (2009). Comparative study of lignins isolated from Alfa grass (Stipa tenacissima L.). Bioresource Technology, 100(14), 3585-3592. doi:10.1016/j.biortech.2009.01.074Belkhir, S., Koubaa, A., Khadhri, A., Ksontini, M., & Smiti, S. (2012). Variations in the morphological characteristics of Stipa tenacissima fiber: The case of Tunisia. Industrial Crops and Products, 37(1), 200-206. doi:10.1016/j.indcrop.2011.11.021Ingard, K. U., & Dear, T. A. (1985). Measurement of acoustic flow resistance. Journal of Sound and Vibration, 103(4), 567-572. doi:10.1016/s0022-460x(85)80024-9Rey, R. del, Alba, J., Arenas, J. P., & Ramis, J. (2013). Technical Notes: Evaluation of Two Alternative Procedures for Measuring Airflow Resistance of Sound Absorbing Materials. Archives of Acoustics, 38(4), 547-554. doi:10.2478/aoa-2013-0064Nelder, J. A., & Mead, R. (1965). A Simplex Method for Function Minimization. The Computer Journal, 7(4), 308-313. doi:10.1093/comjnl/7.4.308Lagarias, J. C., Reeds, J. A., Wright, M. H., & Wright, P. E. (1998). Convergence Properties of the Nelder--Mead Simplex Method in Low Dimensions. SIAM Journal on Optimization, 9(1), 112-147. doi:10.1137/s105262349630347

Absorción acústica de cortinas textiles en función del vuelo

Acoustic absorbing materials are applied to reduce noise levels in a room. They are also used to adjust the reverberation time an acoustic enclosure to use for which it¿s designed. There are multi-purpose rooms for conferences, concerts, cinemas, etc. In this case, the acoustic absorbent materials should be changed according to use. Curtains can be an easy way to modify the acoustics of a room based on usage. This paper presents a study of the acoustic absorption of different curtains under actual placement. The study was performed in a reverberant chamber. It takes into account different textiles. It also takes into account different air plenums and different fullness to pucker. It can be seen in the results, good acoustic behavior of such systems. The acoustic absorption of different fabrics, air plenums and plicate of textiles (fullness) are compared in this work. The good acoustic behaviour of these systems is observed in the results.Rey Tormos, RMD.; Alba Fernández, J.; Blanes, M.; Marco, B. (2013). The Acoustic Absorption of textile curtains on the function of the fullnes. Materiales de Construcción. 63(312):569-580. doi:10.3989/mc.2013.05512S56958063312(4) Navacerrada, M. A.; Díaz, C.; Pedrero, A.; García, L.E.: "Acoustic properties of aluminium foams". Mater. Construcc., vol. 58, nº 291 (2008), pp. 85-98.Ramis, J., Alba, J., Del Rey, R., Escuder, E., & Sanchís, V. J. (2010). Nuevos materiales absorbentes acústicos basados en fibra de kenaf. Materiales de Construcción, 60(299), 133-143. doi:10.3989/mc.2010.50809Del Rey, R., Alba, J., Ramis, J., & Sanchís, V. J. (2011). Nuevos materiales absorbentes acústicos obtenidos a partir de restos de botellas de plástico. Materiales de Construcción, 61(304), 547-558. doi:10.3989/mc.2011.59610Rey, R. del, Alba, J., Arenas, J. P., & Sanchis, V. J. (2012). An empirical modelling of porous sound absorbing materials made of recycled foam. Applied Acoustics, 73(6-7), 604-609. doi:10.1016/j.apacoust.2011.12.009Díaz, C., Jiménez, M., Navacerrada, M. A., & Pedrero, A. (2010). Propiedades acústicas de los paneles de carrizo. Materiales de Construcción, 62(305), 55-66. doi:10.3989/mc.2010.60510(9) Lawrence A.; Architectural Acoustics. Applied Science Publisher, Ltd, Barking, Essex, Inglaterra,(1970).(10) Cavanaugh. W,J,; Wilkes, J.A.: Architectural acoustics: principles and practice. John Wiley & Sons, New York (1998).(11) Egan MD. Architectural Acoustics. J Ross Publishing (2007).Egan, M. D., Quirt, J. D., & Rousseau, M. Z. (1989). Architectural Acoustics. The Journal of the Acoustical Society of America, 86(2), 852-852. doi:10.1121/1.398174Houtsma, A. J. M., Martin, H. J., Hak, C. C. J. M., & van Donselaar, C. J. (1996). Measuring the effectiveness of special acoustic provisions in a concert hall. The Journal of the Acoustical Society of America, 100(4), 2803-2803. doi:10.1121/1.416542(14) Peutz, V.M.A.: "Sound Absorption of Curtains". J Acoust Soc Am, vol. 48, nº 80 (1970).Pirn, R. (1992). Some objective and subjective aspects of three acoustically variable halls. Applied Acoustics, 35(3), 221-231. doi:10.1016/0003-682x(92)90041-pYamada, G., Kobayashi, Y., & Hamaya, H. (1989). Transient response of a hanging curtain. Journal of Sound and Vibration, 130(2), 223-235. doi:10.1016/0022-460x(89)90551-8Soedel, W., Zadoks, R. I., & Alfred, J. R. (1985). Natural frequencies and modes of hanging nets or curtains. Journal of Sound and Vibration, 103(4), 499-507. doi:10.1016/s0022-460x(85)80018-3Chen, Y., & Jiang, N. (2007). Carbonized and Activated Non-wovens as High-Performance Acoustic Materials: Part I Noise Absorption. Textile Research Journal, 77(10), 785-791. doi:10.1177/0040517507080691Shu Yang, Weidong Yu, & Ning Pan. (2010). Investigation of the sound-absorbing behavior of fiber assemblies. Textile Research Journal, 81(7), 673-682. doi:10.1177/0040517510385177Pieren, R. (2012). Sound absorption modeling of thin woven fabrics backed by an air cavity. Textile Research Journal, 82(9), 864-874. doi:10.1177/0040517511429604Ingard, K. U., & Dear, T. A. (1985). Measurement of acoustic flow resistance. Journal of Sound and Vibration, 103(4), 567-572. doi:10.1016/s0022-460x(85)80024-9(26) Carrión, A.: Dise-o acústico de espacios arquitectónicos. Ediciones UPC. 1998.Ramis, J., Alba, J., Martínez, J., & Redondo, J. (2005). The Uncertainty in Absorption Coefficients Measured in Reverberant Chambers: A Case Study. Noise & Vibration Worldwide, 36(1), 7-12. doi:10.1260/095745605349918

Evaluation of two alternative procedures for measuring airflow resistance of sound absorbing materials

[EN] It is well known that sound absorption and sound transmission properties of open porous materials are highly dependent on their airflow resistance values. Low values of airflow resistance indicate little resistance for air streaming through the porous material and high values are a sign that most of the pores inside the material are closed. The laboratory procedures for measuring airflow resistance have been stan- dardized by several organizations, including ISO and ASTM for both alternate flow and continuous flow. However, practical implementation of these standardized methods could be both complex and expensive. In this work, two indirect alternative measurement procedures were compared against the alternate flow standardized technique. The techniques were tested using three families of eco-friendly sound absorbent materials: recycled polyurethane foams, coconut natural fibres, and recycled polyester fibres. It is found that the values of airflow resistance measured using both alternative methods are very similar. There is also a good correlation between the values obtained through alternative and standardized methods.This project has been made possible thanks to the FONDECYT Project 1110605 and the grant GV/2012/066 Projects I+D for emerging research groups. The authors would like to thank Dr. Luis Godinho from the Department of Civil Engineering of University of Coimbra (Portugal) for his help with the experimental work and the ISO data reported in Table 1 of this paper.Rey Tormos, RMD.; Alba Fernández, J.; Arenas, JP.; Ramis Soriano, J. (2013). Evaluation of two alternative procedures for measuring airflow resistance of sound absorbing materials. Archives of Acoustics. 38(4):547-554. https://doi.org/10.2478/aoa:2013-0064S54755438

An electroacoustic method for measuring airflow resistivity of porous sound-absorbing materials

[EN] In this paper, a method for measuring the airflow resistivity of air-saturated porous sound-absorbing materials is presented. The method is based on a modification of the previous device developed by Dragonetti et al. The approach used in the present work involves a cavity and a Helmholtz resonator that are coupled through a loudspeaker so that the complete system behaves as a fourth-order symmetrical band-pass loudspeaker system. After a straightforward calibration, the airflow resistivity of a material sample is indirectly estimated from the direct measurement of the total electric impedance at the loudspeaker connection terminals. In this way, the use of microphones is not necessary, which makes its implementation very simple and inexpensive. Experimental results obtained with the present method agree well with those obtained through a standardized method as long as the values of the material's airflow resistance are not too high. (C) 2019 Elsevier Ltd. All rights reserved.The authors would like to gratefully acknowledge the support of CONICYT-FONDECYT under Grant 1171110 and to the Vicerectorate of R+i+t at Univ. Politecnica of Valencia, Grant PAID0017.Alba, J.; Arenas, JP.; Rey Tormos, RMD.; Rodríguez-Vercher, J. (2019). An electroacoustic method for measuring airflow resistivity of porous sound-absorbing materials. Applied Acoustics. 150:132-137. https://doi.org/10.1016/j.apacoust.2019.02.009S13213715

Comparative Life Cycle Assessment of gypsum plasterboard and a new kind of bio-based epoxy composite containing different natural fibers

[DE] A comparative LCA from cradle to grave between traditional plasterboard, for drywall applications, and different composite boards, made by natural fiber and a bio-based epoxy resin (Supersap CLR), was carried out. The goal of the study was to determine whether the composites based on such a resin combined with natural fibers could be an eco-friendly alternative to plasterboard in the building sector. Moreover, the impacts related to each of the fibers used are also assessed separately from cradle to gate in order to get a better understanding of its influence. Both the results obtained through the IPC. GWP 100a method and the recipe endpoint show a remarkable difference between the plasterboard and all the different composites, the composites offering a 50% reduction in the CO2 emissions. The calculations performed regarding the impacts related to the different fibers showed only small differences between them.The authors gratefully thank the Spanish Ministry of Economy, Industry and Competitiveness, for funding the project BIA2013-41537-R (BIAEFIREMAT 'Development of new sustainable eco-materials and building systems for the building industry, based on the use of residues and renewable raw materials'). The project is co-funded by the European Regional Development Fund and it is included in the R+D National Programme for Research Aimed at the Challenges of Society.Quintana, A.; Alba Fernández, J.; Rey Tormos, RMD.; Guillén Guillamón, IE. (2018). Comparative Life Cycle Assessment of gypsum plasterboard and a new kind of bio-based epoxy composite containing different natural fibers. Journal of Cleaner Production. 185:408-420. https://doi.org/10.1016/j.jclepro.2018.03.042S40842018