Acoustic performance of natural fibres of oil palm frond ( 30%) and acasia magium ( 70%) with thickness of 18mm
Human healthcare is one of the important aspect that need to be pondered upon developing a new technology and invention in this globalisation era. However, a growth development that has occurred in the urban area especially, is believed to be one of the factor that affect the human healthcare sin...
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2023
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| Summary: | Human healthcare is one of the important aspect that need to be pondered upon
developing a new technology and invention in this globalisation era. However, a
growth development that has occurred in the urban area especially, is believed to be
one of the factor that affect the human healthcare since it increase the noise exposure
to the living environment. To curb this issue, developing the sound absorption panel
that is made from natural fibres would be the solution to this problem. Hence, this
thesis would discuss on the acoustic performance of the sound absorbing panel made
by combining two natural fibres, which are Oil palm frond (30%) and Acacia
mangium (70%) at four different targeted densities (110 kg/m3, 120 kg/m3, 130 kg/m3,
and 140 kg/m3) with constant thickness of 18 mm. The sound panel was fabricated
through certain processes that starts with chipping and ends with cooling down
process. The fabrication process involves Phenol Formadihalt (PF) glue that acts as a
binder to the natural fibres and was mixed by using mechanical blending machine.
Once mixed, it was formed in a 30 cm × 30 cm mold before being pressed by a hotpressed
machine at 195 oC for 8 minutes. The fabrication process is an important
phase in determining the acoustic performance of the sound absorbing panel. The
acoustic performance was analyzed based on the Sound Absorption Coefficient (SAC)
that was measured at frequency ranging from 0 Hz until 6400 Hz by using Impedance
Tube method. This analysis was then supported by Scanning Electron Microscope
(SEM) photographs which intended to obtain the morphology of the sound panel
structure. SEM photographs were generated by using JEOL Scanning Electron
Microscope JSM-6010PLUS/LV. From the analysis, it was found that all samples
manage to exhibit minimum SAC value of 0.8 at frequency above 2000 Hz. This
shows that the sound absorbing panel has a good acoustic performance and can be the
best alternative to the synthetic fibre. Moreover, sound panel with density of 110
kg/m3 and 120 kg/m3 has achieved a unity SAC value of 1.0 at mid-range frequency
which are 3512 Hz and 2512 Hz respectively. This indicates that the combination of
natural fibres between Oil palm frond (30%) and Acacia mangium (70%) can be a
good prospect as sound absorbing material as it can fully absorbed the sound waves
that propagate through it. For the morphological analysis based on SEM photographs,
it shows that the presence of pores is the reason for the combined natural fibres to
exhibit good sound absorption. This relates with factor of porosity. When the presence
of pores in a natural fibres with less content of natural fibres itself per unit area of the
material, the more the material can absorb the sound waves that coming through it.
Hence, this explain on why the sample with lower density can exhibit better sound
absorption when compared to the sample with higher density. |
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