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.

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

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.

scholarly journals Sound Absorption Performance of Sugar Palm Trunk Fibers

2019 ◽  
Vol 130 ◽  
pp. 01003
Author(s):  
Anditya Endar Prabowo ◽  
Kuncoro Diharjo ◽  
Ubaidillah ◽  
Iwan Prasetiyo
Keyword(s):  
Absorption Coefficient ◽  
Bulk Density ◽  
Sound Absorption ◽  
Random Noise ◽  
Air Gap ◽  
Sound Absorption Coefficient ◽  
Low Frequencies ◽  
Central Java ◽  
Absorption Performance ◽  
Small Medium Enterprises

The purpose of this research is to investigate the effect of bulk density, thickness, and air gap to sound absorption performance on absorber based sugar palm trunk fibers. The fibers were obtained from solid waste on Small-Medium Enterprises of sago flour processing in Klaten, Central Java, Indonesia. The absorber specimens were formed from the fibers using a simple press molding in an oven at 150 °C. According to ISO 10534-2, the absorber samples were tested using two microphones impedance tube with random noise source to get the curve of the sound absorption coefficient. The result shows that the absorption performance can be improved by increasing bulk density and increasing of sample thickness. Especially at low frequencies, improvement of the sound absorption coefficient can be achieved (NAC > 0.8) by applying the air gap behind the sample. The best performance of absorber based sugar palm trunk fiber can be achieved for (1 000 to 6 000) Hz range frequency.

The Comparison of Sound Absorption of Kapok-Based Fiber Nonwoven Fabrics

2014 ◽  
Vol 1004-1005 ◽  
pp. 562-565 ◽  
Author(s):  
Xue Ting Liu ◽  
Xiong Yan ◽  
Jie Hong ◽  
Hui Ping Zhang
Keyword(s):  
Sound Absorption ◽  
Function Method ◽  
Natural Fiber ◽  
Frequency Region ◽  
Air Gap ◽  
Polyester Fiber ◽  
Kapok Fiber ◽  
Nonwoven Fabrics ◽  
Transfer Function Method ◽  
Absorbing Materials

As a natural fiber, kapok fiber has the high hollow degree that is very good for sound absorption. Four different kinds of kapok-based fiber nonwoven fabrics, made by kapok fiber mixing with hollow polyester, viscose fiber, PP fiber and cotton fiber respectively, were made and the sound absorption coefficients were measured in the frequency region of 100 - 6300 Hz by using a two-microphone transfer-function method. The comparisons of the sound absorption for four types of materials with similar thickness and densities with no air gap and with 1 cm, 3 cm air gap were made. The results indicate that the sound absorption of kapok/hollow polyester fiber nonwoven fabrics is superior to those of other three ones and kapok/hollow polyester fiber nonwoven fabrics can be used for sound-absorbing materials in engineering.

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

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.

scholarly journals Acoustic Properties of Mixing Empty Fruit Bunch and Oil Palm Frond Natural Fibres

2019 ◽  
Vol 8 (4) ◽  
pp. 6347-6349
Keyword(s):  
Oil Palm ◽  
Sound Absorption ◽  
Natural Fibre ◽  
Natural Fibres ◽  
Acoustic Properties ◽  
Empty Fruit Bunch ◽  
Frequency Range ◽  
Oil Palm Frond ◽  
Impedance Tube Method ◽  
Palm Frond

Natural fibre is being studied and used as sound absorber for its promising acoustic properties. For instance, Germany have commercial plants that are producing sound absorbers from natural fibre. Natural fibre is eco-friendly and has no effect on human health. Besides that, the production cost of natural fibre is cheaper than synthetic fibre. This research reported the thickness effects on acoustic properties in different ratios of natural fibres of empty fruit bunch (EFB) and oil palm frond (OPF). Four different thickness of low density fibre board (LDF) have been fabricated (12 mm, 14 mm, 16 mm and 18 mm) in density of 120 kg/m3 . The Sound Absorption Coefficient (SAC) was tested by using the Impedance Tube Method (ITM) according to ASTM E1050-98 standards at frequency from 0 Hz to 6400 Hz. The results show the values of SAC for all samples increase with increasing in thickness from frequency range of 0 Hz – 4500 Hz. It is noteworthy that the LDF with thickness of 16 mm and 18 mm can be classified as Class A sound absorbing material according to sound absorption classes and possess the SAC values of 0.8 and above at a wider frequency range, which is 2500 Hz to 6400 Hz. The combination of EFP and OPF natural fibres has a very promising and excellent performance in acoustic properties.

scholarly journals Improvement of the sound absorption performance of jute felt-based sound absorbers using micro-perforated panels

2017 ◽  
Vol 36 (4) ◽  
pp. 376-398 ◽  
Author(s):  
Pritesh V Bansod ◽  
T Sai Teja ◽  
Amiya R Mohanty
Keyword(s):  
Transfer Matrix Method ◽  
Sound Absorption ◽  
Low Cost ◽  
Control Engineering ◽  
Natural Materials ◽  
Sound Absorber ◽  
Absorbing Materials ◽  
Different Types ◽  
Absorbing Material ◽  
Absorption Performance

In industrial and architectural applications, noise can be controlled using sound-absorbing materials. Natural materials are now gaining importance in the noise control engineering as they have advantages like low cost, eco-friendly, easy to produce, etc. Jute is one of such natural materials, which can be used as a sound-absorbing material. Micro-perforated panels along with three different types of jute felts are used in a multilayer sound absorber configuration to improve its sound absorption. The sound absorption performance of these multilayer sound absorbers is evaluated by using the transfer matrix method and experimental method. Dependence of sound absorption performance on the placement of micro-perforated panels in a multilayer sound absorber is also studied. It is observed that the sound absorption performance depends on the position of micro-perforated panels in a multilayer sound absorber.

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.

Comparative Study on the Effect that Coir Fibers Have on the Dynamic or Quasi-Static Elastic Moduli of Glass Fiber Laminates Obtained by the Vacuum Bag Technique

2015 ◽  
Vol 668 ◽  
pp. 137-144
Author(s):  
Mario Villalón ◽  
Hugo Vega ◽  
Nahary Montoya ◽  
Byron Rubio ◽  
Julio Hernandez ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Glass Fiber ◽  
Tensile Properties ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Natural Fibers ◽  
Standard Test ◽  
Test Method ◽  
Coir Fiber ◽  
Sample Test

The use of natural fibers has a great interest due to their damping properties, low density and moderate strength. The effect of incorporating chopped natural fibers, as disperse reinforced phase, on the dynamic or quasi-static elastic modulus of glass fiber laminates is presented. Squares of 32 cm2 plain wave glass fiber prepreg with epoxy resin were used in a stacking sequence [0]4. Short length chopped (1-3 mm) natural coir fiber was placed in between of each glass fiber prepreg sheet (4) and laminates were prepared by the vacuum bag technique. The volume fraction of natural fiber was 30% (mass fraction of 10%) and samples of 254 mm length and 25.4 mm width were cut and tested at vibration conditions in a cantilever beam arrangement. The vibration frequency was measured by an accelerometer ADXL335 at z-axis, perpendicular to the sample test plane and the elastic modulus was estimated with the cantilever model. The results showed that the samples with coir fiber showed an increase in the dynamic elastic modulus value of 150 to 171% with regard to that one of glass fiber samples without fiber. Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials (ASTM D3039) was also used to further characterize the thin samples (≈0.75 mm) with an Instron machine 8800, 25kN. The tensile properties obtained are lower for coir fiber samples than the ones without.

Biopolymer Foam Composites of Polyurethane Filled with Natural Fiber to Improved Sound Absorption Performance

2018 ◽  
Vol 24 (11) ◽  
pp. 8799-8802
Author(s):  
M. Shafiq M Azahari ◽  
Anika Zafiah M Rus ◽  
Shaharuddin Kormin ◽  
M. Taufiq Zaliran
Keyword(s):  
Sound Absorption ◽  
Natural Fiber ◽  
Absorption Performance

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.

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