Improving Sound Absorption Property of Polyurethane Foams by Adding Tea-Leaf Fibers

Eki̇ci̇, Bülent; Kentli, Aykut; Küçük, Halûk

doi:10.2478/v10168-012-0052-1

Cited by 84 publications

(44 citation statements)

References 20 publications

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“…This is a typical situation for soft PU foams: the low-frequency resonances and anti-resonances of elastic skeleton significantly influence sound propagation and absorption; the flexibility of elastic skeleton may also be utilized in order to improve the acoustic absorption in semi-active (Zielinski, Rak, 2010) or active way (Zielinski, 2008;2010;2011). The sound absorption properties of PU foams may also be improved passively by changing the skeleton density and stiffness -this can be attained by adding some inclusions in the foam matrix, for example, rice hull (Wang et al, 2013), or tea-leaf-fibres (Ekici, 2012). The acoustic absorption curve for a stiff PU foam -thickness 26 mm, curve (d) in Fig.…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

Acoustic Absorption of a New Class of Alumina Foams with Various High-Porosity Levels

Zieliński¹,

Potoczek²,

Śliwa³

et al. 2013

Archives of Acoustics

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Recently, a new class of ceramic foams with porosity levels up to 90% has been developed as a result of the association of the gelcasting process and aeration of the ceramic suspension. This paper presents and discusses original results advertising sound absorbing capabilities of such foams. The authors manufactured three types of alumina foams in order to investigate three porosity levels, namely: 72, 88, and 90%. The microstructure of foams was examined and typical dimensions and average sizes of cells (pores) and cell-linking windows were found for each porosity case. Then, the acoustic absorption coefficient was measured in a wide frequency range for several samples of various thickness cut out from the foams. The results were discussed and compared with the acoustic absorption of typical polyurethane foams proving that the alumina foams with high porosity of 88-90% have excellent sound absorbing properties competitive with the quality of sound absorbing PU foams of higher porosity.

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Section: Discussion Of the Resultsmentioning

confidence: 99%

Acoustic Absorption of a New Class of Alumina Foams with Various High-Porosity Levels

Zieliński¹,

Potoczek²,

Śliwa³

et al. 2013

Archives of Acoustics

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“…Several examples of recycled materials can be found in Del Rey et al (3) with plastic bottle recycling, in Maderuelo et al (4) with tyre recycling, or in Del Rey et al (5) with recycled foams. Other examples of natural based materials can be found in Fatima and Mohanty (6) with jute, in Ramis et al (7) with kenaf, in Ramis et al (8) with coconut, in Diaz et al (9) with reed, in Arenas et al (10) with cellulose, or in Bulent et al (11) with tea fibres. In addition, a review of several absorbing materials can be found in works such as that of Arenas & Crocker (12).…”

Section: Introductionmentioning

confidence: 99%

Small-sized reverberation chamber for the measurement of sound absorption

et al. 2017

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This paper presents the design, construction, calibration and automation of a reverberation chamber for small samples. A balance has been sought between reducing sample size, to reduce the manufacturing costs of materials, and finding the appropriate volume of the chamber, to obtain reliable values at high and mid frequencies. The small-sized reverberation chamber, that was built, has a volume of 1.12 m 3 and allows for the testing of samples of 0.3 m 2 . By using diffusers, to improve the diffusion degree, and automating measurements, we were able to improve the reliability of the results, thus reducing test errors. Several comparison studies of the measurements of the small-sized reverberation chamber and the standardised reverberation chamber are shown, and a good degree of adjustment can be seen between them, within the range of valid frequencies. This paper presents a small laboratory for comparing samples and making decisions before the manufacturing of larger sizes. RESUMEN: Cámara reverberante de tamaño reducido para medidas de la absorción sonora. En este trabajo se muestra el diseño, construcción, calibración y automatización de una cámara reverberante para pequeñas muestras. Se ha buscado un equilibro entre la reducción de tamaño de las muestras para disminuir los costes de fabricación de materiales, y el volumen adecuado que permita obtener valores fiables a determinadas frecuencias. La cámara reverberante construida tiene 1.12 m 3 de volumen y permite la medida de muestras de 0.3 m 2 . La colocación de difusores para aumentar el grado de difusión, y la automatización de las medidas, disminuyen los errores de ensayo. Se muestran también diferentes campañas comparativas de medidas en la cámara reverberante para pequeñas muestras y en la cámara normalizada. Puede verse un buen grado de ajuste entre ambas dentro del rango de frecuencias válido. Por tanto, se muestra un pequeño laboratorio que permite comparar muestras y tomar decisiones, antes de realizar la fabricación de grandes tamaños.PALABRAS CLAVE: Propiedades Acústicas; Coeficiente de Absorción Sonora; Caracterización.ORCID ID: R. del Rey

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“…To replace the use of steel, fiberglass, polypropylene, or nylon as reinforcements for concrete and mortar, natural fibers are proving to be a low-cost, environmentally-friendly alternative. Various laboratories and research groups around the world have conducted studies on construction materials based on or reinforced with plant fibers (Ramis et al 2010;Glé et al 2011;Oldham et al 2011;Asdrubali et al 2012;Ekici et al 2012;Suhawati et al 2013). Among the natural reinforcing filler materials the fique fiber appears to be one of the most promising fibers, due to its high mechanical strength (Delvasto et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Material Based on Short Natural Fique Fibers

Navacerrada¹,

Díaz²,

Fernández³

2014

BioResources

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Fique is a biodegradable natural fiber derived from the Colombian Agavaceae family, originating in tropical America and traditionally used for the manufacture of packaging and cordages. Today, however, new uses are being developed. To meet the need for new good-quality, sustainable, low-cost construction materials for social housing, construction materials have been produced that combine different kinds of natural fibers, including fique, to improve their strength and physical properties. To assess these potential new construction materials made with fique fiber, we have characterized samples of different grammages and thicknesses manufactured using short fique fibers extracted from long fibers. We have measured the sound absorption coefficient at normal incidence in an impedance tube, air flow resistivity, and thermal conductivity as a function of grammage.

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Improving Sound Absorption Property of Polyurethane Foams by Adding Tea-Leaf Fibers

Cited by 84 publications

References 20 publications

Acoustic Absorption of a New Class of Alumina Foams with Various High-Porosity Levels

Acoustic Absorption of a New Class of Alumina Foams with Various High-Porosity Levels

Small-sized reverberation chamber for the measurement of sound absorption

Characterization of a Material Based on Short Natural Fique Fibers

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