Panels of eco-friendly materials for architectural acoustics

[EN] The objective of this work is to study the acoustic and mechanical properties of environmentally friendly materials manufactured through the process of resin infusion made from different types of fibres: some are biodegradable obtained from renewable resources and others from recycled textile waste. The materials studied are composed of fibres of jute, hemp, coconut, biaxial linen and textile waste. The modulus of elasticity and the airborne sound insulation are determined through dynamic and acoustic tests, respectively. The behaviour of these innovative materials is compared to some traditional materials commonly used in architectural acoustics. The acoustic study of these environmentally friendly materials is carried out considering them as light elements of a single layer for their application to insulation of walls. The results are compared to plasterboards, considered as the most commonly used light material in buildings for airborne sound insulation. In conclusion, these materials are a real and effective alternative to the traditional composites of synthetic matrices and reinforcements of glass fibres and there is a reduction in the production cost compared to the usual porous synthetic media that have expensive production processes.Fontoba-Ferrándiz, J.; Juliá Sanchis, E.; Crespo, J.; Segura Alcaraz, JG.; Gadea Borrell, JM.; Parres, F. (2020). Panels of eco-friendly materials for architectural acoustics. Journal of Composite Materials. 54(25):3743-3753. https://doi.org/10.1177/0021998320918914S374337535425Yahya, M. N., Sambu, M., Latif, H. A., & Junaid, T. M. (2017). A study of Acoustics Performance on Natural Fibre Composite. IOP Conference Series: Materials Science and Engineering, 226, 012013. doi:10.1088/1757-899x/226/1/012013Putra, 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.2018.01.029Dunne, R., Desai, D., & Sadiku, R. (2017). Material characterization of blended sisal-kenaf composites with an ABS matrix. Applied Acoustics, 125, 184-193. doi:10.1016/j.apacoust.2017.03.022Mohanty, A. K., Misra, M., & Hinrichsen, G. (2000). Biofibres, biodegradable polymers and biocomposites: An overview. Macromolecular Materials and Engineering, 276-277(1), 1-24. doi:10.1002/(sici)1439-2054(20000301)276:13.0.co;2-wLuckachan, G. E., & Pillai, C. K. S. (2011). Biodegradable Polymers- A Review on Recent Trends and Emerging Perspectives. Journal of Polymers and the Environment, 19(3), 637-676. doi:10.1007/s10924-011-0317-1Belakroum, R., Gherfi, A., Kadja, M., Maalouf, C., Lachi, M., El Wakil, N., & Mai, T. H. (2018). Design and properties of a new sustainable construction material based on date palm fibers and lime. Construction and Building Materials, 184, 330-343. doi:10.1016/j.conbuildmat.2018.06.196Sèbe, G. (2000). Applied Composite Materials, 7(5/6), 341-349. doi:10.1023/a:1026538107200Yates, M. R., & Barlow, C. Y. (2013). Life cycle assessments of biodegradable, commercial biopolymers—A critical review. Resources, Conservation and Recycling, 78, 54-66. doi:10.1016/j.resconrec.2013.06.010Rouison, D., Sain, M., & Couturier, M. (2006). Resin transfer molding of hemp fiber composites: optimization of the process and mechanical properties of the materials. Composites Science and Technology, 66(7-8), 895-906. doi:10.1016/j.compscitech.2005.07.040Sreekumar, P. A., Joseph, K., Unnikrishnan, G., & Thomas, S. (2007). A comparative study on mechanical properties of sisal-leaf fibre-reinforced polyester composites prepared by resin transfer and compression moulding techniques. Composites Science and Technology, 67(3-4), 453-461. doi:10.1016/j.compscitech.2006.08.025Rassmann, S., Reid, R. G., & Paskaramoorthy, R. (2010). Effects of processing conditions on the mechanical and water absorption properties of resin transfer moulded kenaf fibre reinforced polyester composite laminates. Composites Part A: Applied Science and Manufacturing, 41(11), 1612-1619. doi:10.1016/j.compositesa.2010.07.009Vijay, R., & Singaravelu, D. L. (2016). Experimental investigation on the mechanical properties ofCyperus pangoreifibers and jute fiber-based natural fiber composites. International Journal of Polymer Analysis and Characterization, 21(7), 617-627. doi:10.1080/1023666x.2016.1192354Williams, G. I. (2000). Applied Composite Materials, 7(5/6), 421-432. doi:10.1023/a:1026583404899O’Donnell, A., Dweib, M. ., & Wool, R. . (2004). Natural fiber composites with plant oil-based resin. Composites Science and Technology, 64(9), 1135-1145. doi:10.1016/j.compscitech.2003.09.024Tran, P., Graiver, D., & Narayan, R. (2006). Biocomposites synthesized from chemically modified soy oil and biofibers. Journal of Applied Polymer Science, 102(1), 69-75. doi:10.1002/app.22265Liu, Q., & Hughes, M. (2008). The fracture behaviour and toughness of woven flax fibre reinforced epoxy composites. Composites Part A: Applied Science and Manufacturing, 39(10), 1644-1652. doi:10.1016/j.compositesa.2008.07.008Scarponi, C., Pizzinelli, C. S., Sánchez-Sáez, S., & Barbero, E. (2009). Impact Load Behaviour of Resin Transfer Moulding (RTM) Hemp Fibre Composite Laminates. Journal of Biobased Materials and Bioenergy, 3(3), 298-310. doi:10.1166/jbmb.2009.1040Dahy, H. (2017). Biocomposite materials based on annual natural fibres and biopolymers – Design, fabrication and customized applications in architecture. Construction and Building Materials, 147, 212-220. doi:10.1016/j.conbuildmat.2017.04.079Saba, N., Paridah, M. T., & Jawaid, M. (2015). Mechanical properties of kenaf fibre reinforced polymer composite: A review. Construction and Building Materials, 76, 87-96. doi:10.1016/j.conbuildmat.2014.11.043Senthilkumar, K., Saba, N., Rajini, N., Chandrasekar, M., Jawaid, M., Siengchin, S., & Alotman, O. Y. (2018). Mechanical properties evaluation of sisal fibre reinforced polymer composites: A review. Construction and Building Materials, 174, 713-729. doi:10.1016/j.conbuildmat.2018.04.143Alves, C., Ferrão, P. M. C., Silva, A. J., Reis, L. G., Freitas, M., Rodrigues, L. B., & Alves, D. E. (2010). Ecodesign of automotive components making use of natural jute fiber composites. Journal of Cleaner Production, 18(4), 313-327. doi:10.1016/j.jclepro.2009.10.022Van Vuure, A. W., Baets, J., Wouters, K., & Hendrickx, K. (2015). Compressive properties of natural fibre composites. Materials Letters, 149, 138-140. doi:10.1016/j.matlet.2015.01.158Galan-Marin, C., Rivera-Gomez, C., & Garcia-Martinez, A. (2016). Use of Natural-Fiber Bio-Composites in Construction versus Traditional Solutions: Operational and Embodied Energy Assessment. Materials, 9(6), 465. doi:10.3390/ma9060465Bogoeva-Gaceva, G., Avella, M., Malinconico, M., Buzarovska, A., Grozdanov, A., Gentile, G., & Errico, M. E. (2007). Natural fiber eco-composites. Polymer Composites, 28(1), 98-107. doi:10.1002/pc.20270Peng, L., Song, B., Wang, J., & Wang, D. (2015). Mechanic and Acoustic Properties of the Sound-Absorbing Material Made from Natural Fiber and Polyester. Advances in Materials Science and Engineering, 2015, 1-5. doi:10.1155/2015/274913Benfratello, S., Capitano, C., Peri, G., Rizzo, G., Scaccianoce, G., & Sorrentino, G. (2013). Thermal and structural properties of a hemp–lime biocomposite. Construction and Building Materials, 48, 745-754. doi:10.1016/j.conbuildmat.2013.07.096Adekomaya, O., Jamiru, T., Sadiku, R., & Huan, Z. (2015). A review on the sustainability of natural fiber in matrix reinforcement – A practical perspective. Journal of Reinforced Plastics and Composites, 35(1), 3-7. doi:10.1177/0731684415611974Kadam, A., Pawar, M., Yemul, O., Thamke, V., & Kodam, K. (2015). Biodegradable biobased epoxy resin from karanja oil. Polymer, 72, 82-92. doi:10.1016/j.polymer.2015.07.002Yan, L., Chouw, N., & Jayaraman, K. (2014). Flax fibre and its composites – A review. Composites Part B: Engineering, 56, 296-317. doi:10.1016/j.compositesb.2013.08.014Wambua, P., Ivens, J., & Verpoest, I. (2003). Natural fibres: can they replace glass in fibre reinforced plastics? Composites Science and Technology, 63(9), 1259-1264. doi:10.1016/s0266-3538(03)00096-4Williams, C., Summerscales, J., & Grove, S. (1996). Resin Infusion under Flexible Tooling (RIFT): a review. Composites Part A: Applied Science and Manufacturing, 27(7), 517-524. doi:10.1016/1359-835x(96)00008-5Modi, D., Correia, N., Johnson, M., Long, A., Rudd, C., & Robitaille, F. (2007). Active control of the vacuum infusion process. Composites Part A: Applied Science and Manufacturing, 38(5), 1271-1287. doi:10.1016/j.compositesa.2006.11.012Corbière-Nicollier, T., Gfeller Laban, B., Lundquist, L., Leterrier, Y., Månson, J.-A. ., & Jolliet, O. (2001). Life cycle assessment of biofibres replacing glass fibres as reinforcement in plastics. Resources, Conservation and Recycling, 33(4), 267-287. doi:10.1016/s0921-3449(01)00089-1Del Rey, R., Alba, J., Bertó, L., & Gregori, A. (2017). Small-sized reverberation chamber for the measurement of sound absorption. Materiales de Construcción, 67(328), 139. doi:10.3989/mc.2017.0731

Signos y síntomas de adicción al cibersexo en adultos mayores

The use of the Internet for sexual purposes is an increasingly widespread practice at any stage of life. Although in most cases, consumption is done recreationally, sometimes it may become compulsive, uncontrolled, and associated with functional impairment in various areas (addiction to cybersex). Knowing symptoms that characterize this clinical condition is a priority; however, we have poor knowledge about its expression in older adults. Thus, the aim of this work was double: 1) to analyze the prevalence of older adults at risk of developing or showing a pathological profile of cybersex use and 2) to develop a profile of signs and symptoms that characterize it in this population. 538 participants (77% men) over 60 years of age (M = 65.3) completed a series of online sexual behavior scales. 73.2% said they used the Internet with sexual aim. Among them, 80.4% did it recreationally whereas a 20% showed a risk consumption. Among the main symptoms, the most prevalent were the perception of interference 50% of participants), spending greater than 5 hours a week on the Internet for sexual purposes (50%), recognize that they may be doing it excessively (51%) or presence of symptoms of withdrawal (anxiety, irritability, depression, etc.) (24%). This work highlights the relevance of visualizing online risky sexual activity in a silent group and usually outside any intervention for the promotion of online sexual health.El uso de Internet con objetivos sexuales resulta una práctica cada vez más generalizada en cualquier etapa vital. Si bien en la mayoría de casos el consumo se realiza de forma recreativa, en ocasiones  éste puede sobrevenir compulsivo, incontrolado y asociado a un deterioro funcional en diversos ámbitos (adicción al cibersexo). Conocer los síntomas que caracterizan este cuadro clínico constituye una prioridad; sin embargo, disponemos de un pobre conocimiento acerca de su expresión en adultos mayores. Así, este trabajo se planteó con un doble objetivo: 1) analizar la prevalencia de adultos mayores en riesgo de desarrollar o que muestran un perfil patológico de uso del cibersexo y 2) elaborar un perfil de signos y síntomas que lo caracterizan en esta población. Con este objetivo, 538 personas (77% hombres) mayores de 60 años (M=65.3) completaron a través de Internet una serie de escalas de conducta sexual online. El 73.2% afirmaba utilizar internet con objetivo sexual. Entre ellos, el 80.4% lo hacía de forma recreativa y el 19.6% restante mostró un consumo de riesgo. Entre los principales síntomas, destacó la percepción de interferencia (presente en el 50% de los pacientes), pasar mayor que 5 horas semanales en Internet con fin sexual (50%), reconocer que pueden estar haciéndolo excesivamente (51%) o la presencia de síntomas de abstinencia (ansiedad, irritabilidad, depresión, etc.) cuando no pueden acceder a contenidos sexuales (24%). Así, este trabajo destaca la necesidad de visibilizar la actividad sexual online de riesgo en un colectivo silente y normalmente al margen de cualquier intervención para la promoción de la salud sexual online

Experimental investigation of the entrained droplet velocities in a submerged jet injected into a stagnant water pool

[EN] Round turbulent air jets submerged in stagnant water have been studied experimentally in this paper. To achieve this objective a water pool with an air injector has been built and particle image velocimetry visualization techniques (PIV) have been employed to capture images of the submerged jet throughout its spreading. From these images one of the most important variables that characterizes submerged jets the velocity of the entrained droplets, was determined, finding that the function which best fits the entrained droplet velocity distribution is a decreasing exponential function. In addition, a correlation that relates the initial submerged gaseous jet properties, via the gas Reynolds number, with the entrained droplet velocities was developed, in this case via the entrained droplet Reynolds number. (C) 2016 Elsevier Inc. All rights reserved.The authors are indebted to the financial support of MODEX-FLAT project, reference: ENE2013-48565-C2-1-P.Berna, C.; Juliá, J.; Escrivá, A.; Muñoz-Cobo, JL.; Pastor, JV.; Micó, C. (2017). Experimental investigation of the entrained droplet velocities in a submerged jet injected into a stagnant water pool. Experimental Thermal and Fluid Science. 82:32-41. https://doi.org/10.1016/j.expthermflusci.2016.10.036S32418

Influence of the Microstructure in the Acoustical Performance of Consolidated Lightweight Granular Materials

[EN] This paper reports an investigation of the acoustical performance of consolidated lightweight granular materials, made of perlite, arlite and vermiculite mixed with polyurethane resin. These materials could help combat the noise control and replace some products that lack the sufficient structural strength and require expensive protection when exposed to the elements. The advantages of using these composites in acoustic applications, like noise barriers, compared with commercial materials, are their very light mass combined with a relatively high structural strength, high physical chemical stability and low cost. Besides, these materials could be considered more acceptable, from the health point of view, and better suited to operate in an aggressive environment. Acoustical properties were assessed according to ISO 10534 2: 1998. The microstructure, through non-acoustical properties (porosity, tortuosity and flow resistivity), and the acoustical performance (sound absorption spectrum and normalized acoustic impedance) were studied, showing the influence of the non-acoustical properties in the acoustical performance.Maderuelo Sanz, R.; Nadal Gisbert, AV.; Crespo, J.; Barrigón Morillas, J.; Parres, F.; Juliá Sanchis, E. (2016). Influence of the Microstructure in the Acoustical Performance of Consolidated Lightweight Granular Materials. Acoustics Australia. 44(1):149-157. https://doi.org/10.1007/s40857-016-0048-5S14915744