Mohd Faizal Mat Tahir

A Preliminary Study on the Sound Absorption of Date Palm Fibers

In this study sound absorption properties of a single layer date palm fiber has been investigated. Experimental measurements were carried out using impedance tube at the acoustic lab, Faculty of Engineering, Universiti Kebangsaan Malaysia. A constant thickness sample was considered in this study.The results show that the values of absorption coefficient are small at low frequencies, rising with increasing frequency but exhibiting a significant peak. The low density of the sample is reflected in the overall sound absorption performance of the date palm fiber. An improvement in the sound absorption in the lower frequency range was achieved by backing the sample with air gap of different thicknesses of 10 mm, 20 mm and 30 mm. The increase in the air gap thickness moved the peaks toward lower frequencies and improved the low frequencies absorption. However, that increase coincided with reduction of absorption in medium frequency range and reduction in the absorption peak. A linear relationship was found between sound absorption peaks and the air gap thickness. The performance of the date palm fiber can be improved by increasing the density of the sample, using different sample thicknesses and adding perforated plates to the date palm fiber panel.

Analysis of Sound Absorption of Date Palm Fibers Based on Flow Resistivity

This paper presents a study on the sound absorption properties of a single layer date palm fiber based on the flow resistivity. Experimental measurements were carried out to estimate the flow resistivity value using differential pressure tube. The average diameter of the fibers is 0.462 mm. A date palm fiber sample of 25mm thickness is used in this research. The flow resistivity of the date palm fiber sample was found to be 4.26 kPa.s/m2. The flow resistivity was used to calculate the sound absorption coefficient using Delany and Bazley model. The simulation showed that the values of absorption coefficient are small at low frequencies and rising with increasing frequency. To check the effect of flow resistivity on the sound absorption coefficient Delany and Bazley model was simulated for three different flow resistivity values. The simulation results showed that the sound absorption coefficient increases with the increase of the flow resistivity.

Car Body and Chassis Development of UKM CARevo for Perodua Eco-Challenge 2011

This paper presents the development of the UKM Perodua Eco-Challenge vehicle, CARevo in terms of aesthetic design, novel fabrication of car body and superior chassis design. The objective of the competition was to develop a fuel efficient car which was competent to travel the longest distance using 0.5 liter of RON95 fuel with some rules and regulation verified by the Perodua to be followed. The UKM CARevo was powered by a 660cc fuel injection engine with manual 5-speed transmission with the total of 3450 mm, 1500 mm and 1106 mm for its length, wide and height. Several design such as space frame chassis design, composite bodywork result from fiberglass with resin, aerodynamic design of car body and are the key features that is discussed in this paper.

Sound absorption properties of a low-density perforated date palm fibres panel

Sound absorption properties of a natural waste of a low density date palm fibre perforated panel have been presented. The measurements were carried out for a single layer sample using an impedance tube. A simulation was performed using Delany and Bazley model for the sound absorption coefficient for the single layer date palm fibre. The experiment was conducted for the panel with and without perforated plate facing. Three air gap thicknesses were used between the date palm fibre sample and the rigid backing of the impedance tube to study the effect of the air gap on the sound absorption. The results showed an improvement on the sound absorption coefficient at higher and lower frequency ranges when facing the panel with perforated plate. Further studies could be conducted to check the effect of different densities and perforations on the sound absorption of the date palm fibres.

Development of Semi-Active Panel Design for Sound Absorption

Various noise-absorbing materials and apparatus were developed not only for industry purposes but also for increased personal convenience through the absorption of unwanted sound. Absorbing products are typically passive mediums, whereas active-control absorption is expensive and complicated to install. Thus, in this study, a semi-active panel design for the sound absorber is developed to ensure operation at a required absorption level for a particular environment and to allow manual control. This study focused on producing an optimum design from several blueprints by using the simulation program, WinFlag. Simulation results are validated by using the impedance tube method. The samples used are perforated plates with open areas of 5%, 7.5%, 10%, 12.5%, and 15%. The second layer is a 35-mm thick coconut coir fiber as the main absorbing material. The third layer is air cavity. Simulation results indicate that the panel with perforation plates with 15% open areas gained the highest peak of sound absorption coefficient (0.851) at 5000 Hz. By using 30 mm thick air cavities, the highest peak is 0.963 at 3129 Hz. Experimental results indicate that the highest peak of sound absorption coefficient is 0.847 for the 15% open area of perforated plates, whereas the highest peak is 0.934 when 30 mm thick air cavities are used. The same pattern in the overall results denotes that the experiment result agrees with that of the simulation

The Study of Thermal Comfort and Noise Level in Battery Plate Factory

The successful of manufacturing factories in industry is highly dependent on a productivity of their employees especially operators. It was identified that comfort and noise level can reduce the productivity of their workers. This study is to determine the level of thermal and noise comfort in the battery plate factory. This study was conducted in three days and location of the study is at battery plate factory in Semenyih, Selangor, Malaysia. The scope of study is focused at plate manufacturing area where the employee estimated 40 persons. The thermal comfort level can be determined by calculating PMV and PPD. This study involved six factors of comfort which is air temperature, average radiant temperature, air velocity, relative humidity, metabolic rate and clothes insulation. Then the study of noise level was conducted by determining LAeq, T, Lmax and Lmin. To carry out this study, Babuc-A equipment were used. The analysis show the area of the manufacturing battery plate having a discomfort condition and PMV result is between 1.5 until 3. Air temperature on the other hand is between 27.4°C-37.8°C while relative humidity is between range 35.35% -92.1% and air velocity 0 m/s-1.28 m/s. Meanwhile the LAeq,T value in the factory is varied from 68 to 80 dB.

Material Characterization by Using Non-Contact Ultrasonic Method

Non-destructive characterization of material is given more attention due to its advantages in cost of research, procedure of experiment, accuracy of results and time taken to undergo experiment. As compare to other non-destructive characterization method, non-contact ultrasonic method does not need physical contact with specimen, surface specimen no need special preparation, analysis of any stage of formation of specimen and non-hazardous.This study is to carry out the experiment of material characterization by using non-contact ultrasonic method. First, the grid on the specimen is identifying by plot the chart grid in 5x5 mm size grid. Next, ‘surfer’software will generate a contour map, specimenimage and wire-frame image for each specimen by using the data taken. According to the specimenimage and wire-frame image, the shape, position of the defects of specimen and the change of density of defects can be identified. The area of defects of specimen is calculated by using the mean value calculation method. The accuracy of calculation area of defects is calculated by comparing the area of defects by experimental and theoretical. The result of this study shows the accuracy of this study depend of the ratio of size of defects which is the area of defects and grid size which is the area of data be taken.

Effect of Density on the Sound Absorption of Date Palm Fibers

An experimental study on the effect of panel density on the sound absorption properties of a date palm fiber panel has been presented in this paper. The experiments were carried out by using impedance tube at the Acoustic Lab, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia. The date palm fiber was tested for densities of 77 kg/m3, 100 kg/m3 and 125 kg/m3.The results show that the values of absorption coefficient improve when increasing the density of the panel. Noise reduction coefficient (NRC) was computed to compare the performance of the palm date fiber samples for the different densities. The NRC increases by increasing the density.

Monitoring system of fuel injector using piezoelectric sensors

The performance of a fuel injector greatly influences the performance of a vehicle engine. An effective monitoring system is capable of detecting damage, instability, and even the life of fuel injector. In this study, a test rig on fuel injector using piezoelectric film sensor has been developed. Three parameters, namely, pulse width at 5, 10, and 15 ms; frequency at 17, 20, and 25 Hz; and pressure at 10, 50, and 70 bar were used for observation. These parameters were set at different combinations to obtain the different injection patterns of the fuel injector. Statistical methods were used to analyze the data, with the aid of the Matlab software. The injection pattern was described using a new I-kaz (Ƶ) statistical parameter, which is intended to provide a simple explanation of the corresponding correlations between the coefficient of I-kaz and the statistical parameters, such as root mean square, Skewness, and Kurtosis, to obtain effective information on the operation state of the fuel injector. The results showed that higher pulse width results in a higher I-kaz coefficient, which also increases with an increase in frequency and varies with pressure; however, the pattern depends on the pulse width. The I-kaz scatter graph against skewness showed a clear pattern among the statistical parameters. The corresponding correlation was useful for monitoring the fuel injector and can be used as a reference for future studies.

Automotive noise insulation composite panel using natural fibres with different perforation areas

This research was carried out to study the acoustic properties of natural organic fibres; kenaf and coir fibres using impedance tube method. Kenaf fibre was used as noise absorber filler in an insulation panel while the coir fibre as reinforcement in the perforated composite panel. The perforated panel was made from coir fibre/polyester composites with coir fibre volume fraction of 10%, 20% and 30%. The perforation area of the perforated panel was also varied at 10%, 20% and 30%. During the processing stage, the kenaf fibre sheet has been treated with PVA and cut into 100 mm and 30 mm diameter sample for low and high frequency test. The density of the coir fibre is determined to be 32.2 g/cm3 while the density of the kenaf fibre is 42.6 g/cm3. The tests were carried out using impedance tube at acoustic lab, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia using ISO 10534-2 standard for noise absorption coefficients to determine their noise absorption coefficient. The results obtained show that the optimum noise absorption coefficient index for kenaf fibre is 0.8 with 10% fibre volume fraction of coir fibre/polyester perforated composites panel at 10% perforation areas.