scholarly journals A Pilot Study on the Sound Absorption Characteristics of Chicken Feathers as an Alternative Sustainable Acoustical Material

2019 ◽  
Vol 11 (5) ◽  
pp. 1476 ◽  
Author(s):  
Asniawaty Kusno ◽  
Kimihiro Sakagami ◽  
Takeshi Okuzono ◽  
Masahiro Toyoda ◽  
Toru Otsuru ◽  
...  
Keyword(s):  
Pilot Study ◽  
Sound Absorption ◽  
Prediction Method ◽  
Fibrous Materials ◽  
Absorption Coefficients ◽  
Chicken Feathers ◽  
Absorption Performance ◽  
Flow Resistivity ◽  
Impedance Tube Method ◽  
Absorption Characteristics

This communication reports the results of a pilot study on the sound absorption characteristics of chicken feathers (CFs). Recently, demands for natural and sustainable materials have been extensively studied for acoustical purposes. CF has long been left wasted, however, they can be used for sound-absorbing purposes to improve acoustical environments as a sustainable and green acoustical material. In order to clarify their feasibility, samples of CF absorbers of various densities and thicknesses were prepared, and their sound absorption coefficients were measured by the standard impedance tube method. The measured results were also compared with those of conventional glass wools of the same densities and thicknesses. The results show that CFs have potentially good sound-absorption performance, which is similar to typical fibrous materials: increasing with frequency. Results of direct comparison with glass wool demonstrate that the absorption coefficients of CFs are comparable and, at some frequencies, somewhat higher than conventional glass wools in some cases. Additionally, the first step for searching a prediction method for the sound absorption performance of CFs, their flow resistivity was measured and a Delany–Bazley–Miki model was examined. However, the resultant flow resistivity was unexpectedly low, and the model gave only a much lower value than that measured. The reason for the discrepancies is the subject of a future study.

scholarly journals Surface Tension Effect on Sound Absorption Characteristics of a Cavity-Backed Semi-Permeable Membrane

2015 ◽  
Vol 773-774 ◽  
pp. 23-27 ◽  
Author(s):  
Muhd Hafeez Zainulabidin ◽  
L.M. Wan ◽  
Al Emran Ismail ◽  
M.Z. Kasron ◽  
A.S.M. Kassim
Keyword(s):  
Surface Tension ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Membrane Surface ◽  
Surface Tension Effect ◽  
Permeable Membrane ◽  
Reduction Coefficient ◽  
Absorption Performance ◽  
Impedance Tube Method ◽  
Absorption Characteristics

This paper describes the analysis on the characteristics of semi-permeable membrane sound absorber. The effects of membrane surface tension on the sound absorption characteristics were investigated. The characteristics of the membrane absorber was measured experimentally in terms of Sound Absorption Coefficient, α and Noise Reduction Coefficient, NRC. The membrane is made of thin, flexible, semi-permeable latex material and the tests were carried out by using impedance tube method according to ISO 10534-2 standard. The results showed that the surface tension has significant influence on the sound absorption characteristics. For the parameters used in the laboratory work, specimen with unstretched surface tension has the best absorption performance.

scholarly journals Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1091 ◽  
Author(s):  
Dengke Li ◽  
Daoqing Chang ◽  
Bilong Liu
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Porous Materials ◽  
Sound Absorption ◽  
Azimuthal Angle ◽  
Octave Band ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Perforated Plates ◽  
Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

scholarly journals Application of transparent microperforated panel to acrylic partitions for desktop use: A case study by prototyping

2021 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kusaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi
Keyword(s):  
Adverse Effect ◽  
Sound Absorption ◽  
Acoustic Environment ◽  
Actual Use ◽  
Acrylic Sheet ◽  
Absorption Performance ◽  
The Subject ◽  
Droplet Penetration ◽  
Absorption Characteristics

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to a possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.

Sound absorption of a finite flexible micro-perforated panel absorber back by a rigid air cavity filled with a fibrous porous material

2021 ◽  
Vol 263 (3) ◽  
pp. 3625-3632
Author(s):  
Ho Yong Kim ◽  
Yeon June Kang
Keyword(s):  
Energy Dissipation ◽  
Porous Material ◽  
Fibrous Material ◽  
Alternative Energy ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Absorption Coefficients ◽  
Air Cavity ◽  
Acoustic Cavity ◽  
Absorption Performance

Back by a rigid cavity filled with a layer of porous layer, the sound absorption performance of a micro-perforated panel (MPP) can be enhanced in comparison with other resonance based sound absorbers. In this paper, a theoretical model of a finite flexible MPP back by a rigid air cavity filled with a fibrous porous material is developed to predict normal sound absorption coefficients. Displacements of MPP and sound pressure field in fibrous porous material and acoustic cavity are expressed using a series of modal functions, and the sound absorption coefficients of MPP system are obtained. Additionally, comparison of energy dissipation by MPP and fibrous material is performed to identify effects of a fibrous material on the sound absorption of a MPP. As expected, at anti-resonance frequency of an MPP, the fibrous material provide an alternative energy dissipation mechanism.

scholarly journals Optimization and Validation of Sound Absorption Performance of 10-Layer Gradient Compressed Porous Metal

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 588 ◽  
Author(s):  
Fei Yang ◽  
Xinmin Shen ◽  
Panfeng Bai ◽  
Xiaonan Zhang ◽  
Zhizhong Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Sound Absorption ◽  
Search Algorithm ◽  
Theoretical Data ◽  
Porous Metal ◽  
Cuckoo Search ◽  
Absorption Coefficients ◽  
Element Simulation ◽  
Absorption Performance

Sound absorption performance of a porous metal can be improved by compression and optimal permutation, which is favorable to promote its application in noise reduction. The 10-layer gradient compressed porous metal was proposed to obtain optimal sound absorption performance. A theoretical model of the sound absorption coefficient of the multilayer gradient compressed porous metal was constructed according to the Johnson-Champoux-Allard model. Optimal parameters for the best sound absorption performance of the 10-layer gradient compressed porous metal were achieved by a cuckoo search algorithm with the varied constraint conditions. Preliminary verification of the optimal sound absorber was conducted by the finite element simulation, and further experimental validation was obtained through the standing wave tube measurement. Consistencies among the theoretical data, the simulation data, and the experimental data proved accuracies of the theoretical sound absorption model, the cuckoo search optimization algorithm, and the finite element simulation method. For the investigated frequency ranges of 100–1000 Hz, 100–2000 Hz, 100–4000 Hz, and 100–6000 Hz, actual average sound absorption coefficients of optimal 10-layer gradient compressed porous metal were 0.3325, 0.5412, 0.7461, and 0.7617, respectively, which exhibited the larger sound absorption coefficients relative to those of the original porous metals and uniform 10-layer compressed porous metal with the same thickness of 20 mm.

scholarly journals Improving and Optimizing Sound Absorption Performance of Polyurethane Foam by Prepositive Microperforated Polymethyl Methacrylate Panel

2020 ◽  
Vol 10 (6) ◽  
pp. 2103
Author(s):  
Xiaocui Yang ◽  
Xinmin Shen ◽  
Haiqin Duan ◽  
Fei Yang ◽  
Xiaonan Zhang ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Composite Structures ◽  
Sound Absorption ◽  
Search Algorithm ◽  
Cuckoo Search ◽  
Cuckoo Search Algorithm ◽  
Absorption Model ◽  
Absorption Coefficients ◽  
Element Simulation ◽  
Absorption Performance

Sound absorption performance of polyurethane foam could be improved by adding a prepositive microperforated polymethyl methacrylate panel to form a composite sound-absorbing structure. A theoretical sound absorption model of polyurethane foam and that of the composite structure were constructed by the transfer matrix method based on the Johnson–Champoux–Allard model and Maa’s theory. Acoustic parameter identification of the polyurethane foam and structural parameter optimization of the composite structures were obtained by the cuckoo search algorithm. The identified porosity and static flow resistivity were 0.958 and 13078 Pa·s/m2 respectively, and their accuracies were proved by the experimental validation. Sound absorption characteristics of the composite structures were verified by finite element simulation in virtual acoustic laboratory and validated through standing wave tube measurement in AWA6128A detector. Consistencies among the theoretical data, simulation data, and experimental data of sound absorption coefficients of the composite structures proved the effectiveness of the theoretical sound absorption model, cuckoo search algorithm, and finite element simulation method. Comparisons of actual average sound absorption coefficients of the optimal composite structure with those of the original polyurethane foam proved the practicability of this identification and optimization method, which was propitious to promote its practical application in noise reduction.

Sound Absorption Characteristics of Porous Steel Manufactured by Lost Carbonate Sintering

2009 ◽  
Vol 1188 ◽  
Author(s):  
Miao Lu ◽  
Carl Hopkins ◽  
Yuyuan Zhao ◽  
Gary Seiffert
Keyword(s):  
Absorption Coefficient ◽  
Pore Size ◽  
Sound Absorption ◽  
Single Layer ◽  
Normal Incidence ◽  
Sound Absorption Coefficient ◽  
Absorption Coefficients ◽  
Impedance Tube ◽  
Absorption Characteristics

AbstractThis paper investigates the sound absorption characteristics of porous steel samples manufactured by Lost Carbonate Sintering. Measurements of the normal incidence sound absorption coefficient were made using an impedance tube for single-layer porous steel discs and assemblies comprising four layers of porous steel discs. The sound absorption coefficient was found not to vary significantly with pore size in the range of 250-1500 μm. In general, the absorption coefficient increases with increasing frequency and increasing thickness, and peaks at specific frequencies depending on the porosity. An increase in porosity tends to increase the frequency at which the sound absorption coefficient reaches this peak. An advantage was found in using an assembly of samples with gradient porosities of 75%-70%-65%-60% as it gave higher and more uniform sound absorption coefficients than an assembly with porosities of 75%.

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

2015 ◽  
Vol 773-774 ◽  
pp. 247-252 ◽  
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.

scholarly journals Application of transparent microperforated panel to acrylic partitions for desktop use: A case study by prototyping

2021 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kussaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi
Keyword(s):  
Adverse Effect ◽  
Future Study ◽  
Sound Absorption ◽  
Acoustic Environment ◽  
Actual Use ◽  
Acrylic Sheet ◽  
Absorption Performance ◽  
The Subject ◽  
Absorption Characteristics

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.

scholarly journals Comparison of sound absorption characteristics measured by impedance tube method and ensemble averaging technique on porous clay bricks

2021 ◽  
Vol 42 (3) ◽  
pp. 154-157
Author(s):  
Siwat Lawanwadeekul ◽  
Reiji Tomiku ◽  
Noriko Okamoto ◽  
Toru Otsuru ◽  
Masahiro Masuda ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Ensemble Averaging ◽  
Impedance Tube ◽  
Averaging Technique ◽  
Clay Bricks ◽  
Impedance Tube Method ◽  
Absorption Characteristics
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