Application of In Situ Method for Measuring Sound Absorption Coefficient of Direct Piercing Carved Wood Panel with Daun sireh Motif

2013 ◽  
Vol 471 ◽  
pp. 273-278
Author(s):  
Mohd Zamri Bin Jusoh ◽  
Mohamad Ngasri Dimon ◽  
Nazli Bin Che Din ◽  
Toru Otsuru ◽  
You Kok Yeow
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Wood Panel ◽  
Natural Sunlight ◽  
Absorption Performance ◽  
Air Circulation ◽  
Lower Frequencies

An application of In-Situ method of measuring sound absorption coefficient on the surface of direct piercing carved wood panel using the concept of ensemble averaged is discussed. The method offer an easier way to measure the absorption performance for each individual aperture of carved wood panel with floral pattern which was replicated from one of the oldest mosque, namely Masjid Abidin located in Terengganu, Malaysia. Two pieces of 20 mm thick of cengal wood (Neobalanocarpus heimii) with 30% and 40% perforation ratio were respectively measured in a reverberation room in order to determine the value of . At lower frequencies (0.1 kHz-1.5 kHz), the measured values of for both direct piercing carved wood panel with floral pattern (Daun Sireh motif) are shown that the sound absoption for both direct piercing carved wood panel are in perform level. From the measurements, clearly, the installation of the direct piercing carved wood panel with floral pattern (Daun Sireh motif) in the Masjid Abidin can provide better air circulation and additional natural sunlight, as well as better sound intelligibility inside the building.

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.

scholarly journals Effect of Thickness and Perforation Size on the Acoustic Absorption Performance of a Micro-Perforated Panel

2021 ◽  
Vol 335 ◽  
pp. 03016
Author(s):  
Yi-San Wong ◽  
Vignesh Sekar ◽  
Se Yong Eh Noum ◽  
Sivakumar Sivanesan
Keyword(s):  
Absorption Coefficient ◽  
Urban Areas ◽  
Sound Absorption ◽  
Rapid Development ◽  
Noise Pollution ◽  
Sound Absorption Coefficient ◽  
Sound Insulation ◽  
Acoustic Absorption ◽  
Psychological Disturbance ◽  
Absorption Performance

In current times, noise pollution is especially apparent in urban areas due to rapid development in transportation, industrialization, and urbanization. The worsening noise pollution is detrimental to human health and behaviour as it can contribute to disorders and psychological disturbance. Thus, noise regulation is crucial and must be addressed with immediate effect. Micro-perforated panels (MPP) can be a potential solution to mitigate noise on a commercial scale. Researchers have addressed the mechanics behind the enhancement of acoustic absorption through micro-perforation and some suggestions have been made, such as the effect of structural variation on sound absorption performance. Hence, this research aims at optimizing the sound absorption performance of an MPP by determining the connection between thickness and perforation size with sound absorption coefficient. Three cases were considered: (i) varying perforation size, (ii) varying thickness, and (iii) varying perforation size and thickness simultaneously. Based on the Maa prediction model, the sound absorption performance for all three cases have been simulated through the MATLAB software. Results show that the increase in both thickness and perforation size together increases the peak value of sound absorption coefficient (SAC). It also shifts the peak towards the higher frequency region and narrows the bandwidth. The findings of this study indicate the potential of thick MPPs as commercial sound absorbers by adjusting the size of perforations. Thicker and sturdier MPPs with optimal acoustic resistance and reactance can act as reliable sound absorbers for sound insulation purposes.

COMPARISON OF NORMAL INCIDENT SOUND ABSORPTION COEFFICIENT OF DIRECT PIERCING CARVED WOOD PANEL FOR CIRCULAR, GEOMETRY AND FLORAL DESIGN

2016 ◽  
Vol 78 (6-10) ◽  
Author(s):  
Mohd Zamri Jusoh ◽  
Nazli Che Din ◽  
Mohamad Ngasri Dimon
Keyword(s):  
Boundary Element Method ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Sound Intensity ◽  
Normal Incidence ◽  
Sound Absorption Coefficient ◽  
Wood Panel ◽  
High Frequencies ◽  
Wood Carving ◽  
Circular Design

Direct Piercing Carved Wood Panel (DPCWP) is among the famous Malay wood carving art in the Malay culture. It is the best example of Malay people’s creativity and masterpiece. In this paper, the comparison of normal incidence sound absorption coefficient,  (SAC) for three major types of design for the DPCWP is discussed. The simplest form of DPCWP, the circular type, then the geometry and floral types were investigated based on simulation and measurement works using sound intensity method to determine the normal incidence SAC, for 30% and 40% perforation ratios. The simulation work was carried out by using BEASY Acoustic software based on Boundary Element Method (BEM). From the results, there is an identical trend for DPCWP with geometry and floral design from 250 Hz to 4 kHz. At high frequencies (1 kHz to 4 kHz), both design show the tendency of decrement, suggesting that the complexity of the design does affect the average SAC value. However, for circular design, SAC is higher than other design at 1 kHz and shows a similar trend with other design at 2 kHz and 4 kHz for both simulation and measurement result.

scholarly journals Building Sound Absorption Performance Model of Porous Glass Based on GRNN

2019 ◽  
Vol 37 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Xubo Zhang ◽  
Ying Xu ◽  
Tingying Zhang ◽  
Guodong Li
Keyword(s):  
Absorption Coefficient ◽  
Porous Glass ◽  
Sound Absorption ◽  
Performance Model ◽  
Sound Absorption Coefficient ◽  
Average Error ◽  
Generalized Regression Neural Network ◽  
Prediction Curve ◽  
Absorption Performance ◽  
Two Parameters

The generalized regression neural network (GRNN) model of sound absorption coefficient of porous glass was built on data from 16 groups gained by experiments, where 12 groups were randomly selected as trained samples and the other 4 groups were as tested ones. This GRNN model which has two parameters, porosity and thickness as the inputs, was set the maximum iteration number 20, getting the optimal trained spread parameter σ=0.1. The results showed that the average error of this model was 0.003, and this model has high precision and the prediction curve of the sound absorption coefficient was very similar to the experiments. The advantages of this method are simple, needing less trained samples, rapid and accurate.

Acoustic Absorption Performance Research of Coir Density Board

2012 ◽  
Vol 549 ◽  
pp. 589-592
Author(s):  
Jia Yao ◽  
Li Li Ma ◽  
Lu Wei ◽  
Li Wei Jiang ◽  
Ya Qin Li
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Optimization Design ◽  
Morphological Characteristics ◽  
Wave Impedance ◽  
Sound Absorption Coefficient ◽  
Coir Fiber ◽  
Tropical Fruit ◽  
Practical Applications ◽  
Absorption Performance

Coir fiber is one of the tropical fruit fibers, the effective use of coir is not comprehensive now and the phenomenon of resources waste still exists. Full study of the advantage characteristics of coir has important significance for the expansion of the application field of coir resources. This article determines the light porous characteristics of coir from the micro-morphological characteristics. Through the prediction model research of the sound absorption coefficient of the porous fiber materials, the optimization density and the optimization thickness ranges can be got for the coir density board, so as to guide the optimization design of the sound absorption performance of coir density board. The changing rule of the sound absorption coefficient of the coir density board has been got by adopting the wave impedance tube method and the sound absorption coefficients by adding 5cm air gap has also been researched. The results of the experiments confirm that coir density board can be used as a secondary noise absorption material; the practical applications of coir density board are as the lightweight wall, the car interior trim or seat filling materials and the shipping cabins materials, to reduce the corresponding environment noise.

scholarly journals Sound absorption characteristics of three species (binuang, balsa and paulownia) of low density hardwood

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Eun-Suk Jang ◽  
Chun-Won Kang
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Gas Permeability ◽  
Sound Absorption Coefficient ◽  
Low Density ◽  
High Porosity ◽  
Sound Waves ◽  
Low Frequencies ◽  
Absorption Performance ◽  
Closed Pore

Abstract In this study, the sound absorption coefficient of three low density hardwoods – binuang, balsa and paulownia – were investigated. Their gas permeability and pore size were measured, and their pore shapes were classified into through pore, blind pored, and closed pore, as specified by the International Union of Pure and Applied Chemistry (IUPAC). Among the three species, obvious that paulownia had lowest sound absorption when the two of others showed higher sound absorption. Although paulownia is a high porosity wood, most of its vessels are blocked by tyloses; it is therefore difficult for sound waves to enter its pores, which results in poor sound absorption performance. This study showed that the higher the through pore porosity, the higher was the gas permeability, which led to improvement of the sound absorption performance. It was also found that the sound absorption coefficient of the three species woods increased at low frequencies as the size of an air cavity between the specimens and tube’s wall increased.

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