Papers by Keyword: Sound Absorption

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Authors: Jia Horng Lin, You Cheng Liao, Chao Chiung Huang, Chia Chang Lin, Chin Mei Lin, Ching Wen Lou
Abstract: In this study, the basic material for sound absorption was porous nonwoven made of polyester nonwoven and low-melting polyester fiber. Nonwoven was then attached with foam polyurethane as composite plank for sound absorption and sound isolation. We used two microphone impedance tubes for sound absorption test and INSTRON 5566 mechanical testing machine for tensile test. The optimum sound absorption coefficients as 0.67 ± 0.008 was obtained when density of foam polyurethane was 1.0 Kg/m3 with thickness of 20 mm; Polyester nonwoven were 9 layers; and low-melting polyester fiber was 30 wt% with thickness of 10 mm. Specimens obtained the maximum fracture stress when it contained low-melting polyester fiber at 30~40 wt%. The results of this study could be applied in the partitions inside ships, vehicles or buildings.
1801
Authors: Jia Horng Lin, Chia Chang Lin, Chao Chiung Huang, Ching Wen Lin, You Cheng Liao, Ching Wen Lou
Abstract: In this study, the basic material for sound absorption was porous nonwoven made of polyester nonwoven and low-melting polyester fiber. Nonwoven was then attached with foam polyurethane as composite plank for sound absorption and sound isolation. We used two microphone impedance tube for sound absorption test and INSTRON 5566 mechanical testing machine for tensile test. The optimum sound absorption coefficients as 0.67 ± 0.008 was obtained when density of foam polyurethane was 1.0 Kg/㎥ with thickness of 20 mm; Polyester (PET) nonwoven were laminated with 9 layers in a total thickness of 10 mm; and its low-melting polyester fiber was 30 wt%. The composite plank obtained the maximum fracture stress when it contained low-melting-point (low-Tm) PET fiber at 30~40 wt%. The results of this study could be applied in the partitions inside ships, vehicles or buildings.
1933
Authors: Jia Horng Lin, Ying Huei Shih, Jin Mao Chen, Ching Wen Lou
Abstract: Following the high quality of life that people pursue, the requirements to air and environment are stricter. People value the quality of sleeping and public safety, thus they pay more attention to prevent noises. Noise makes people weary and distracted, and may eventually result in accidents. Therefore, this study uses polylactide fiber (PLA) and low melting point polylactide fiber (LPLA) to make sound absorbent PLA/LPLA plates, after which the tensile strength, softness, and sound absorption of the plates are evaluated.
460
Authors: Jia Horng Lin, Che Wei Li, Ching Wen Lou
Abstract: In this study, two agents (a foaming agent and a hardener) are mixed to form rigid polyurethane (PU) foams with various densities, which are separately poured into a mold with a three-dimensional (3D) fabric to form 3D fabric/foam composites. The mechanical property and sound absorbency of the composites are examined. The experiment results show that an increasing density of the two-agent mixture results in a more compact PU foam, a 31 % increase in bursting strength, and a greater resilience, but also a decrease in the sound absorbency coefficient. In sum, variations in the density of the mixture have an impact on the physical properties of the fabric/foam composites, the derived results of which can thus be further applied to product designs.
242
Authors: Jia Horng Lin, Chia Chang Lin, Chao Chiung Huang, Ching Wen Lin, Kuan Hsun Su, Ching Wen Lou
Abstract: Five testing matrixes were prepared to test with sound absorption, tensile strength, and thermal conductivity respectively. The low-melting-point (low-Tm) polyester (PET) fibers were blended with weight ratios (10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt %) with PET staples, forming the PET nonwoven fabrics. The thermoplastic polyurethane (TPU) was thermal bounded with the nonwoven fabrics with different lamination number to examine the sound absorption rate, creating the PET/ TPU composites. Afterward, four sets of samples – PET nonwoven fabrics and PET/ TPU composites with TPU films laminated on the front, in the middle, and on the rear of the composites, were compared. PET/ TPU composite with TPU film laminated in the middle exhibited the optimum sound absorption; moreover, 30 wt% was proved to be the optimum parameter of the low-Tm PET fibers for the PET/ TPU composites.
1968
Authors: Azma Putra, Muhammad Sajidin Py, Norliana Salleh
Abstract: Micro-perforated panel (MPP) is well known as the alternative green sound absorbing material replacing the synthetic porous absorber. Several works have been established which model the sound absorption performance of the MPP with various arrangements. However, most existing models are for MPP with rigid condition and rarely discuss the effect of vibration due to the impinging sound. In this paper, a simple approach using wave propagation technique is proposed to take into account the effect of flexural wave in the MPP on its sound absorption. The model begins with an MPP coupled with a solid panel separated by an air gap. The impedance of the back solid panel can then be adjusted to a very large value to simulate a rigid wall.
255
Authors: Serik Omarov, Turarbek Begimov, Makhabbat Tukibayeva, Khamaria Maylina, Gulnara Bedelbaeva
Abstract: Based on phonon theory the interaction of high frequency sound (ultrasound and hypersonic) with crystal lattices in solids was estimated. The coefficients of absorption in dielectrics and metals, with respect to temperature and sound frequency, were calculated. Analysis of the calculated dependences allows obtaining of nanomaterials with the set sound conductivity and sound absorption in high frequency range.
328
Authors: Martina Reif, Jiří Zach
Abstract: With development and reconstruction of traffic routes there has recently been an increased need for noise reduction measures, out of which the most effective one appears to be the construction of noise barriers that prevent sound propagation from its source and (in case of sound absorbing barriers) absorb sound and thus reduce the noise load near the sound source (around a traffic route). The manufacturing of noise barriers often enables the use of secondary raw materials and thus to reduce the energy and material costs of their production as well as decrease the environmental impact. An interesting option is the use of recycled concrete that is suitable for production of concrete with open structure to be used in the absorber layer of a sound barrier and can even be used in the structural layer as well. The paper describes the possibilities of using recycled concrete in the production of sound absorbing barriers with a high degree of sound absorption.
120
Authors: Kai Liang Qi, Guang Cheng Zhang, Song Ming Li, Liang Wei Liu, Zhen He
Abstract: High performance polyimide (PI) foam has been prepared by esterification method using benzophenone tetracarboxylic acid dianhydride (BTDA) and diamino diphenylmethane (MDA) as the main materials in the mixture of methanol and tetrahydrofuran (THF). The cellular structure, thermal properties and flame retardance properties of PI foam were characterized by hot stage optical microscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetic analysis (TGA) and limiting oxygen Index (LOI), respectively. The results showed that the cellular structure was more ideal when the particle diameter of polyester ammonium salt (PEAS) precursor powder was 100μm; the glass transition temperature (Tg) of PI foam was more than 300°C, 5% weight loss temperature was above 500°C, LOI was as high as 50% and sound absorption was over 0.5.
66
Authors: Jia Horng Lin, Chen Hung Huang, Yu Chun Chuang, Ching Wen Lou
Abstract: Factories have increased the mechanical equipment on a mass scale as a result of quick growth of global industry, and the unbearable sounds that machines create while operating become noise. Therefore, versatility of building materials that are highly correlated to human habitat has been gaining attention. This study combines and then needle-punches fire-retardant polyester (PET) fibers and recycled Kevlar selvages to make PET/Kevlar nonwoven fabrics, which are then combined with Polyurethane (PU) foams, a product yielded after Polyol and Isocyanate (MDI) foam and cure, to form PET/Kevlar/PU foam composite boards. During the process, PET fibers and Kevlar fibers are blended with various ratios and the density of the PU foams is varied. The resilience rate, burst strength, and sound absorption of the resulting composite boards are tested. The test results show that increasing Kevlar selvages can heighten the resilience rate but decreases the burst strength of the composite boards.
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