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Sinin Hamdan - One of the best experts on this subject based on the ideXlab platform.
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Comparative study of Sound Absorption Coefficients of coir/kenaf/sugarcane bagasse fiber reinforced epoxy composites
Key Engineering Materials, 2017Co-Authors: Elammaran Jayamani, Muhammad Khusairy Bin Bakri, Soon Kok Heng, Sinin HamdanAbstract:This research focuses on the Sound Absorption Coefficient of three different natural fibers reinforced epoxy composites. The natural fibers used are coconut coir, kenaf, and sugarcane bagasse. All of these fibers were mixed with epoxy resin and hardener with a ratio of 4:1. The mixtures were then poured into a circular mold and compressed by using compression molding technique. It was left for curing for 24 hours at standard room temperature. The results were obtained using the two-microphone transfer functions impedance tube method according to ASTM E1050-12. It is found that as the fiber loading increased, the Sound Absorption Coefficient of the composites increased. 20wt% Coconut coir epoxy composites and 20wt% kenaf fiber epoxy composites have the highest Sound Absorption Coefficient with almost similar Sound Absorption of 0.078 at 5000Hz. While, 20wt% sugarcane bagasse epoxy composites have Sound Absorption of 0.075 at 5000Hz.
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comparative study of Sound Absorption Coefficients of coir kenaf sugarcane bagasse fiber reinforced epoxy composites
Key Engineering Materials, 2017Co-Authors: Elammaran Jayamani, Soon Kok Heng, Muhammad Khusairy Bin Bakri, Sinin HamdanAbstract:This research focuses on the Sound Absorption Coefficient of three different natural fibers reinforced epoxy composites. The natural fibers used are coconut coir, kenaf, and sugarcane bagasse. All of these fibers were mixed with epoxy resin and hardener with a ratio of 4:1. The mixtures were then poured into a circular mold and compressed by using compression molding technique. It was left for curing for 24 hours at standard room temperature. The results were obtained using the two-microphone transfer functions impedance tube method according to ASTM E1050-12. It is found that as the fiber loading increased, the Sound Absorption Coefficient of the composites increased. 20wt% Coconut coir epoxy composites and 20wt% kenaf fiber epoxy composites have the highest Sound Absorption Coefficient with almost similar Sound Absorption of 0.078 at 5000Hz. While, 20wt% sugarcane bagasse epoxy composites have Sound Absorption of 0.075 at 5000Hz.
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An Experimental and Simulation Studies on Sound Absorption Coefficients of Banana Fibers and their Reinforced Composites
Nano Hybrids and Composites Vol, 2016Co-Authors: Muhammad Khusairy Bin Bakri, Elammaran Jayamani, Kok Heng Soon, Sinin Hamdan, Akshay KakarAbstract:This research focuses on the simulation of Sound Absorption Coefficient of banana fiber and experimentation of Sound Absorption Coefficient of banana fiber epoxy composites. For simulation, ‘Mechel’ empirical model was used to manipulate the flow resistivity and ‘Delany and Bazley’ empirical model was used to develop the prediction of Sound Absorption Coefficient at frequency ranges from 500 Hz to 6000 Hz. For experimentation, two-microphone transfer function impedance tube model was used to analyze the Sound Absorption Coefficient at frequency ranges from 500 Hz to 6000 Hz. Based on simulation, it is predicted and analyzed that the Sound Absorption Coefficient of banana fiber found to be as high as 0.97 for the effects on the material thickness of banana fiber and 0.64 for the effects on the fiber diameter size and flow resistivity of banana fiber in the frequency ranges from 500 Hz to 6000 Hz. According to experimental results, it is observed and analyzed that the Sound Absorption Coefficient of banana epoxy composites found to be as high as 0.11 for untreated banana epoxy composites and 0.12 for treated banana epoxy composites in the frequency ranges from 500 Hz to 6000 Hz.
Mohamad Ngasri Dimon - One of the best experts on this subject based on the ideXlab platform.
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comparison of normal incident Sound Absorption Coefficient of direct piercing carved wood panel for circular geometry and floral design
Jurnal Teknologi, 2016Co-Authors: Mohd Zamri Jusoh, Mohamad Ngasri DimonAbstract: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.
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application of in situ method for measuring Sound Absorption Coefficient of direct piercing carved wood panel with daun sireh motif
Applied Mechanics and Materials, 2013Co-Authors: Mohd Zamri Jusoh, Mohamad Ngasri Dimon, Toru Otsuru, You Kok YeowAbstract: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.
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normal incidence Sound Absorption Coefficient of direct piercing carved wood panel with daun sireh motif using boundary element method
International Journal of Automotive and Mechanical Engineering, 2013Co-Authors: Mohd Zamri Jusoh, Mohamad Ngasri Dimon, You Kok Yeow, Rafidah RosmanAbstract:The Direct Piercing Carved Wood Panel (DPCWP) installed in Masjid Abidin, Kuala Terengganu, is one example that carries much aesthetic and artistic value. The use of DPCWP in earlier mosques was envisaged to improve the intelligibility of indoor speech because the perforated panels allow some of the Sound energy to pass through. In this paper, the normal incidence Sound Absorption Coefficient of DPCWP with Daun Sireh motif, which is a form of floral pattern, is discussed. The Daun Sireh motif was chosen and investigated for 30%, 35%, 40%, and 45% perforation ratios. The simulations were conducted using BEASY Acoustic Software based on the boundary element method. The simulation results were compared with measurements obtained by using the Sound intensity technique. An accompanying discussion on both the numerical and the measurement tendencies of the Sound Absorption characteristics of the DPCWP is provided. The results show that the DPCWP with Daun Sireh motif can act as a good Sound absorber. © Universiti Malaysia Pahang.
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Sound Absorption Coefficient of direct piercing carved wood panel with uniform geometric patterns
2009 International Conference for Technical Postgraduates (TECHPOS), 2009Co-Authors: Mohamad Ngasri Dimon, Abdul Wahab Ishari Hashim, Siti Zaleha Abdul Hamid, Mokhtar Harun, Fareha Abdul Rahman, Siti Dhalia Adzim Muhamod AdzimAbstract:Direct piercing carved wood panels (DPCWP) have been used as part of the wall panel for mosques in this country. Among the earliest used of DPCWP is as in Masjid Sultan Zainal Abidin in 1700s, Kuala Terengganu, Terengganu. It is envisage, the use of DPCWP is to help in achieving good speech intelligibility inside. This is considering DPCWP allowing Sound waves to pass through, hence Sound reflection to the main prayer is contain. Minimizing Sound reflection toward the mosque main area, ensuring optimization of speech intelligibility. DPCWP has the ability to allow Sound waves to pass through the panel. This qualifies DPCWP as Sound absorber material. This as Sabine, Kutruff and Maekawa definition of Sound Absorption Coefficient. In this paper the Sound Absorption Coefficient of DPCWP with uniform geometric patterns are discussed. The perforation ratios are 31% and 37%. Numerical experiments were conducted using Boundary Element Method (BEM). The measured results were obtained using Sound intensity measurements technique. Comparison of Sound Absorption Coefficient obtained through numerical experiment and measured using Sound intensity are discussed in details. Analysis of resonance frequencies due to types and sizes of apertures in relation to Sound Absorption Coefficient also highlighted. The measured and numerical results suggest, DPCWP of uniform geometric patterns indeed able to act as good Sound absorber. This finding allows DPCWP to be used as Sound absorber more effectively in future mosque construction.
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normal incidence Sound Absorption Coefficient of direct piercing carved wood panel with star and diamond dominated geometric patterns
Annual Conference of the Australian Acoustical Society 2009 - Acoustics 2009: Research to Consulting, 2009Co-Authors: Mohamad Ngasri Dimon, Abdul Wahab Ishari Hashim, Mokhtar Harun, Siti Zaleha, Abdul Hamid, Siti DhaliaAbstract:Direct piercing carved wood panels (DPCWP) are wooden panels carved with numerous patterns and elements. They are used in traditional houses, palaces, mosques and other buildings. In mosques, DPCWP are used as parts of wall panel and for the upper partition of doors and windows. Among the earliest DPCWP were in the Sultan Zainal Abidin mosque in 1700s, Kuala Terengganu, Malaysia. The current DPCWP usage in the modern mosques is mainly for esthetic and as a reflection of traditional Malay wood carving. In contrast, the use of DPCWP in earlier mosques was to help achieving good indoor speech intelligibility. DPCWP has the ability to allow Sound waves to pass through the panel, hence Sound reflection to the main prayer area is contained. Minimizing Sound reflection toward the mosque main area ensures optimization of speech intelligibility. This qualifies DPCWP as a Sound absorber material, inline with Sabine, Kutruff and Maekawa definition of Sound Absorption Coefficient. In this paper, the normal incidence Sound Absorption Coefficient of DPCWP with star and diamond dominated geometric patterns are discussed. This star and diamond patterns were chosen and designed for 33% and 38% perforation ratios. Numerical experiments were conducted using Boundary Element Method (BEM) while measured results were obtained using Sound intensity measurements technique. Comparisons of Sound Absorption Coefficient obtained through both methods are discussed in details. Analysis of resonance frequencies due to the types and sizes of apertures in relation to Sound Absorption Coefficient are also highlighted. The measured and numerical results suggest that DPCWP dominated with star and diamond dominated geometric patterns are able to act as good Sound absorber. This finding suggests that DPCWP could be used as effective Sound absorbers in future mosques construction.
Elammaran Jayamani - One of the best experts on this subject based on the ideXlab platform.
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Comparative study of Sound Absorption Coefficients of coir/kenaf/sugarcane bagasse fiber reinforced epoxy composites
Key Engineering Materials, 2017Co-Authors: Elammaran Jayamani, Muhammad Khusairy Bin Bakri, Soon Kok Heng, Sinin HamdanAbstract:This research focuses on the Sound Absorption Coefficient of three different natural fibers reinforced epoxy composites. The natural fibers used are coconut coir, kenaf, and sugarcane bagasse. All of these fibers were mixed with epoxy resin and hardener with a ratio of 4:1. The mixtures were then poured into a circular mold and compressed by using compression molding technique. It was left for curing for 24 hours at standard room temperature. The results were obtained using the two-microphone transfer functions impedance tube method according to ASTM E1050-12. It is found that as the fiber loading increased, the Sound Absorption Coefficient of the composites increased. 20wt% Coconut coir epoxy composites and 20wt% kenaf fiber epoxy composites have the highest Sound Absorption Coefficient with almost similar Sound Absorption of 0.078 at 5000Hz. While, 20wt% sugarcane bagasse epoxy composites have Sound Absorption of 0.075 at 5000Hz.
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comparative study of Sound Absorption Coefficients of coir kenaf sugarcane bagasse fiber reinforced epoxy composites
Key Engineering Materials, 2017Co-Authors: Elammaran Jayamani, Soon Kok Heng, Muhammad Khusairy Bin Bakri, Sinin HamdanAbstract:This research focuses on the Sound Absorption Coefficient of three different natural fibers reinforced epoxy composites. The natural fibers used are coconut coir, kenaf, and sugarcane bagasse. All of these fibers were mixed with epoxy resin and hardener with a ratio of 4:1. The mixtures were then poured into a circular mold and compressed by using compression molding technique. It was left for curing for 24 hours at standard room temperature. The results were obtained using the two-microphone transfer functions impedance tube method according to ASTM E1050-12. It is found that as the fiber loading increased, the Sound Absorption Coefficient of the composites increased. 20wt% Coconut coir epoxy composites and 20wt% kenaf fiber epoxy composites have the highest Sound Absorption Coefficient with almost similar Sound Absorption of 0.078 at 5000Hz. While, 20wt% sugarcane bagasse epoxy composites have Sound Absorption of 0.075 at 5000Hz.
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An Experimental and Simulation Studies on Sound Absorption Coefficients of Banana Fibers and their Reinforced Composites
Nano Hybrids and Composites Vol, 2016Co-Authors: Muhammad Khusairy Bin Bakri, Elammaran Jayamani, Kok Heng Soon, Sinin Hamdan, Akshay KakarAbstract:This research focuses on the simulation of Sound Absorption Coefficient of banana fiber and experimentation of Sound Absorption Coefficient of banana fiber epoxy composites. For simulation, ‘Mechel’ empirical model was used to manipulate the flow resistivity and ‘Delany and Bazley’ empirical model was used to develop the prediction of Sound Absorption Coefficient at frequency ranges from 500 Hz to 6000 Hz. For experimentation, two-microphone transfer function impedance tube model was used to analyze the Sound Absorption Coefficient at frequency ranges from 500 Hz to 6000 Hz. Based on simulation, it is predicted and analyzed that the Sound Absorption Coefficient of banana fiber found to be as high as 0.97 for the effects on the material thickness of banana fiber and 0.64 for the effects on the fiber diameter size and flow resistivity of banana fiber in the frequency ranges from 500 Hz to 6000 Hz. According to experimental results, it is observed and analyzed that the Sound Absorption Coefficient of banana epoxy composites found to be as high as 0.11 for untreated banana epoxy composites and 0.12 for treated banana epoxy composites in the frequency ranges from 500 Hz to 6000 Hz.
André De Boer - One of the best experts on this subject based on the ideXlab platform.
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a numerical study of a method for measuring the effective in situ Sound Absorption Coefficient
Journal of the Acoustical Society of America, 2012Co-Authors: Erwin R Kuipers, Ysbrand H Wijnant, André De BoerAbstract:The accuracy of a method [Wijnant et al., “Development and applica- tion of a new method for the in-situ measurement of Sound Absorption”, ISMA 31, Leuven, Belgium (2010).], for measurement of the effective area-averaged in situ Sound Absorption Coefficient is investigated. Based on a local plane wave assump- tion, this method can be applied to Sound fields for which a model is not available. Investigations were carried out by means of finite element simulations for a typical case. The results show that the method is a promising method for determining the effective area-averaged in situ Sound Absorption Coefficient in complex Sound fields.
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A numerical study of a method for measuring the effective in situ Sound Absorption Coefficient.
The Journal of the Acoustical Society of America, 2012Co-Authors: Erwin R Kuipers, Ysbrand H Wijnant, André De BoerAbstract:The accuracy of a method [Wijnant et al., Proc. of ISMA 31, Leuven, Belgium (2010), Vol. 31] for measurement of the effective area-averaged in situ Sound Absorption Coefficient is investigated. Based on a local plane wave assumption, this method can be applied to Sound fields for which a model is not available. Investigations were carried out by means of finite element simulations for a typical case. The results show that the method is a promising method for determining the effective area-averaged in situ Sound Absorption Coefficient in complex Sound fields.
Hyeon Choe - One of the best experts on this subject based on the ideXlab platform.
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chemical treatment of wood fibers to enhance the Sound Absorption Coefficient of flexible polyurethane composite foams
Composites Science and Technology, 2018Co-Authors: Hyeon Choe, Giwook SungAbstract:Abstract Polyurethane foams are commonly used as Sound Absorption materials in the automobile industry because their well-defined structure allows for effective Absorption of Sound waves through air friction and the structural vibration of cell walls. In this study, chemically treated wood fibers were incorporated into the polyurethane foams to improve their Sound Absorption Coefficient by enhancing the compatibility between the wood fibers and the polyurethane matrix. The open porosity of the composite foams was strongly dependent on the chemical treatments of wood fibers as well as the wood fiber contents in the composites, and it was related to the air-flow resistivity and tortuosity of the foam materials. Model calculations revealed that high air-flow resistivity led to a high Sound Absorption Coefficient, which agreed well with experimental observations. Therefore, for achieving high Sound Absorption performance in composite foams, no more than the optimum amount of a coupling agent must be used to improve the interfacial compatibility between the wood fibers and the polyurethane matrix. The use of excessive amount of the silane coupling agent led to intramolecular agglomeration, thus negatively affecting the Sound Absorption behavior.