Room sound absorption provided by underbench sound absorbing material.

In this paper, the influence of different combination of different density of nonwoven materials on the sound-absorption capability is studied through the serial experiments. The results show that the structure with low density on the surface material and dense density in the middle of the material will have better capacity in absorbing sound.

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A Preliminary Study on Acoustical Performance of Oil Palm Mesocarp Natural Fiber

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.773-774.247 ◽

2015 ◽

Vol 773-774 ◽

pp. 247-252 ◽

Cited By ~ 4

Author(s):

Hanif Abdul Latif ◽

Musli Nizam Yahya ◽

Mohamed Najib Rafiq ◽

Mathan Sambu ◽

Mohd Imran Ghazali ◽

...

Keyword(s):

Oil Palm ◽

Sound Absorption ◽

Natural Fiber ◽

Standard Test ◽

Air Gap ◽

Test Method ◽

Synthetic Materials ◽

Absorbing Material ◽

Absorption Performance ◽

Impedance Tube Method

As the population increases, the demand of a comfortable environmental such as sound pollution is getting higher. Sound pollutions also have become worsen and creating concerns for many peoples. Due to this problem, synthetic materials as acoustic absorbers still applied as commonly acoustical panels and this material may hazardous to human health and contribute significantly a pollution to the environments. However, researchers have interested in conducting their research on natural fiber to be an alternative sound absorber. This study investigated the potential of oil palm Mesocarp fiber for sound absorbing material. The Mesocarp fibers were mixed with polyurethane (PU) as binder with ratio of 70:30. The thickness was varied in 10mm, 20mm, 30mm, and 40mm. This study also investigated the air gap of 5mm and 10mm in the sound absorption performance. Impedance Tube Method was used to measure sound absorption coefficient (a). The measurement was done on accordance with ASTM E1050-98, which is the standard test method for impedance and absorption of acoustical materials using a tube. The results showed that the optimum value for Mesocarp fiber is 0.93. The optimum value obtained at 5000 Hz. The influence of air gap increases the sound absorption especially from 250 Hz to 4000 Hz. These results indicate that fiber from Mesocarp is promising to be used sound absorbing material.

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Modelling the Effect of Flexural Vibration on Sound Absorption of a Micro-Perforated Panel Using Wave Propagation Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.471.255 ◽

2013 ◽

Vol 471 ◽

pp. 255-260

Author(s):

Azma Putra ◽

Muhammad Sajidin Py ◽

Norliana Salleh

Keyword(s):

Wave Propagation ◽

Sound Absorption ◽

Flexural Vibration ◽

Rigid Wall ◽

Flexural Wave ◽

Wave Propagation Method ◽

Rigid Condition ◽

Absorbing Material ◽

Absorption Performance ◽

Propagation Technique

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.

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Sustainable Rigid Polyurethane Foam from Wasted Palm Oil and Water Hyacinth Fiber Composite—A Green Sound-Absorbing Material

Polymers ◽

10.3390/polym14010201 ◽

2022 ◽

Vol 14 (1) ◽

pp. 201

Author(s):

Nathapong Sukhawipat ◽

Laksana Saengdee ◽

Pamela Pasetto ◽

Jatupol Junthip ◽

Ekkachai Martwong

Keyword(s):

Polyurethane Foam ◽

Palm Oil ◽

Water Hyacinth ◽

Sound Absorption ◽

Fiber Composite ◽

Mesh Size ◽

Alternative Material ◽

Absorbing Material ◽

Used Palm Oil ◽

Water Hyacinth Fiber

A novel rigid sound-absorbing material made from used palm oil-based polyurethane foam (PUF) and water hyacinth fiber (WHF) composite was developed in this research. The NCO index was set at 100, while the WHF content was set at 1%wt with mesh sizes ranging from 80 to 20. The mechanical properties, the morphology, the flammability, and the sound absorption coefficient (SAC) of the PUF composite were all investigated. When the WHF size was reduced from 80 to 20, the compression strength of the PUF increased from 0.33 to 0.47 N/mm2. Furthermore, the use of small fiber size resulted in a smaller pore size of the PUF composite and improved the sound absorption and flammability. A feasible sound-absorbing material was a PUF composite with a WHF mesh size of 80 and an SAC value of 0.92. As a result, PUF derived from both water hyacinth and used palm oil could be a promising green alternative material for sound-absorbing applications.

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Influence of Sound-Absorbing Material Placement on Room Acoustical Parameters

Acoustics ◽

10.3390/acoustics1030038 ◽

2019 ◽

Vol 1 (3) ◽

pp. 644-660 ◽

Cited By ~ 1

Author(s):

Jose Cucharero ◽

Tuomas Hänninen ◽

Tapio Lokki

Keyword(s):

Speech Intelligibility ◽

Sound Absorption ◽

Sound Field ◽

Acoustical Parameters ◽

Open Plan ◽

Absorbing Material ◽

The Impact

The reverberation of a room is often controlled by installing sound absorption panels to the ceiling and on the walls. The reduced reverberation is particularly important in classrooms to maximize the speech intelligibility and in open-plan offices to make spaces more pleasant. In this study, the impact of the placement of the absorption material in a room was measured in a reverberation room and in a mockup classroom. The results show that absorption material is less efficient if it is mounted to the corners or on the edges between the walls and ceiling, if the sound field is more or less diffuse. If the room modes dominate the sound field, the most efficient location for the sound-absorbing material was found at one of the surfaces causing the modes. The results help acoustical consultants to place the absorption material in optimal locations and, generally, minimize the amount of material and save costs.

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The influence of the distribution of sound absorbing materials on the estimation of reverberation time in rooms

E3S Web of Conferences ◽

10.1051/e3sconf/20184900078 ◽

2018 ◽

Vol 49 ◽

pp. 00078

Author(s):

Marcelina Olechowska ◽

Artur Nowoświat ◽

Jan Ślusarek ◽

Mateusz Latawiec

Keyword(s):

Absorption Coefficient ◽

Acoustic Field ◽

Sound Absorption ◽

Sound Field ◽

Reverberation Time ◽

Type D ◽

Absorbing Materials ◽

Absorbing Material ◽

Different Dimensions ◽

Materials Used

Reverberation time in rooms depends on many factors, e.g. cubature, surface of envelopes, sound absorption coefficient of materials used for the construction of the envelopes, geometry of rooms or the distribution of sound absorbing materials. The arrangement of sound absorbing materials in rooms has an impact on the dispersion of acoustic field, yet theoretical calculation models do not take into account this impact. According to these models, regardless of the arrangement of sound absorbing materials, the reverberation time in a room will remain unchanged. The present paper investigates the above problem by means of computer simulations. For the needs of the simulation, three rooms with different dimensions were adopted, i.e. type 'p' - a cuboidal room with a square base, type 'd' - a cuboidal room (with one side of the 'p' room lengthened), type 'w' - a cuboidal room (with the height of the room lengthened 'p'). During the simulation, the way of acoustic field dispersion was being changed and its influence on the reverberation time in the rooms was being determined. The authors investigated two situations. The first one involved a non-dampened room, in which the sound absorbing material was being arranged differently. The second one involved a welldampened room, and the dispersion of sound field was analyzed depending on the location of the reflecting material.

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Valorisation of Tannery Waste and Animal By-Product for Acoustics Applications

Journal of the American Leather Chemists Association ◽

10.34314/jalca.v116i6.4308 ◽

2021 ◽

Vol 116 (6) ◽

Author(s):

Tesfay Gebryergs ◽

C. Sivaranjani ◽

N. Nishad Fathima

Keyword(s):

Sound Absorption ◽

Natural Fiber ◽

Waste Utilization ◽

Strength Analysis ◽

Leather Industry ◽

Molding Method ◽

Absorbing Material ◽

Impedance Tube Method ◽

Porosity Measurements ◽

Different Thickness

Disposal of chromium-containing solid wastes generated from the leather industry poses a major threat to tanners worldwide. Herein, we propose a strategy to utilize chrome shaving waste for sound absorption application by blending it with natural fiber, wool. The composites were prepared at various ratios with different thickness by compression molding method and subjected to characterizations like scanning electron microscope, porosity measurements, and tensile strength analysis. The sound absorption behavior of the composites was evaluated using the two-microphone impedance tube method. The results indicate that the composites with higher thickness show better sound absorption at higher frequencies when compared to the natural wool and composites with lesser thicknesses. Thus, this material can be used as a sound-absorbing material thereby paving the alternative use of leather waste utilization.

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Study of a Sound Absorbing Polyurethane Based on Porous Composite Material

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.275-277.1623 ◽

2013 ◽

Vol 275-277 ◽

pp. 1623-1627 ◽

Cited By ~ 2

Author(s):

Xin Liang Zhang ◽

Cun Ping Liu

Keyword(s):

Sound Absorption ◽

Glass Fibers ◽

Low Frequency ◽

Wave Tube ◽

Porous Composite ◽

Blowing Agent ◽

Reduction Coefficient ◽

Absorbing Material ◽

New Type ◽

Standing Wave Tube

A new type of sound absorbing material, which was made from super strength polyurethane and mass fiber, was investigated. And the sound absorption coefficient of the material was tested by standing wave tube method. Experiment results manifested that content of glass fibers, blowing agent and thickness have great effects on the sound absorbing performance of the sample. When the content of glass fiber and blowing agent are separately 3% and 0.4%, the performance of the material reaches optimum. The noise reduction coefficient of the material is 0.6, and the sound absorption property at middle-low frequency is good.

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Acoustic Benefits of Ecofriendly Spent Tea Leaves Filled Porous Material

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.739.125 ◽

2017 ◽

Vol 739 ◽

pp. 125-134

Author(s):

Kylie Wong ◽

Qumrul Ahsan ◽

Azma Putra ◽

Sivarao Subramonian ◽

Noraiham Mohamad ◽

...

Keyword(s):

Absorption Coefficient ◽

High Resistance ◽

Sound Absorption ◽

Transmission Loss ◽

Acoustic Property ◽

Tea Plant ◽

Sound Absorption Coefficient ◽

Acoustic Performance ◽

Absorbing Material ◽

Tea Leaf

This paper demonstrates the feasibility of spent tea leaf (STL) fiber as an eco-friendly sound absorbing material. STL fiber is a by-product which was extracted from tea plant. STL are rich in polyphenols (tannins) which cause high resistance to fungal and termites, and high resistance to fire. In addition, STL are hollow and cellular in nature and thus perform well as acoustic and thermal insulators. Three different grades of STL were studied and the acoustic property was analyzed in terms of sound absorption coefficient and transmission loss. Experimental measurements of sound absorption coefficient in impedance tube are conducted. It was found that finest STL fiber grade exhibits better acoustic performance among others. Furthermore, the effect of latex binder on the acoustic property of STL fiber was also analyzed. Results suggest that the types of binder such as polyurethane and latex influenced the acoustic performance of STL fiber.

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Influence of Thickness and Density of Nonwoven Sound-Absorbing Material on the Sound-Absorption Capability

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.440 ◽

2011 ◽

Vol 197-198 ◽

pp. 440-443 ◽

Cited By ~ 6

Author(s):

Wen Su ◽

Xiao Ming Qian ◽

Xin Yu Li ◽

Shu Sen Liu

Keyword(s):

Absorption Coefficient ◽

Sound Absorption ◽

Sound Absorption Coefficient ◽

Low Density ◽

Density Structure ◽

High Frequencies ◽

Material Thickness ◽

Nonwoven Materials ◽

Absorbing Material

In this paper, the influence of thickness and density of nonwoven materials on the sound-absorption capability is studied through the serial experiments. The results show that the sound-absorption coefficient increases with material thickness increasing and this relationship is more distinct for low or mid frequencies than for high frequencies. When the material thickness is made constant, the sound-absorption coefficient increases with density increasing for low-mid frequencies, while the coefficient decreases with density for high frequencies. The conclusion is that the nonwoven materials with low density structure own better capacity in absorbing sound according to the experiment results.

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