Mohammad Khairul Azhar Abdul Razab

A study of particulate matter concentration released during laser paint removal process on car coated substrate

Normalization mass (N) of particulate matter (PM) per one laser shot and 1.0 cm2 released during the laser irradiation were measured on three different types of car coated substrate samples A, B and C by using DustTrak Aerosol Monitor 8520. The highest N of PM1.0 and PM10.0 were 0.0485 mg/shot/cm2 and 0.0766 mg/shot/cm2 mg/shot/cm2 safe than conventional chemical stripping process in term of health implications prevention and safety managements. beam size for Sample A, 0.0890 mg/shot/cm2 and 0.0634 mg/shot/cm2 and 0.1728 mg/shot/cm2 for Sample B and 0.0530 for Sample C, respectively. Laser paint removal technique is considered

Estimation of Threshold Fluence, Absorption Coefficient and Thermal Loading of Car Coated Substrate in Laser Paint Removal

Threshold fluence (FT), absorption coefficient (α) and thermal loading (γ) were estimated on three types of car coated substrate by applying Beer-Lambert law. Cynosure Cynergy Pulse Nd:YAG was using to irradiate 54 substrate samples and the depth of coating removed (d) was obtained by using Alicona IFM G4. Depth of coating removed (d) versus laser fluence (F) graphs was plotted for each pulse width (PW), repetition rate (RR) and beam size (BS) considered by measuring the average of coating removal efficiency (ε). The best interceptions of certains ε with their X-axis were selected for each sample A, B and C, representing their general FT, α and γ respectively.

Potential of Fabricated Light Foamed Concrete in Reducing Radon from Building Material

Three of Light Foamed Concrete (LFC) have been obtain by using different formula of Cement:Aggregates. The brick was locate into a closed Perspex box and the net of 222Rn concentration level have been measured for 5 consecutive days. The results show the LFC 3 has produced the lowest of net 222Rn concentration level in air, followed by LFC 2 and LFC 1, respectively. The result also show the 222Rn concentration level have been influenced by the temperature and relative humidity in air.

A review of incorporating Nd:YAG laser cleaning principal in automotive industry

Abstract Laser cleaning has been identified as an ideal technology to replace conventional chemical techniques in the motorcar coating removal process to maintain the sustainability of our environment. This is due to the unique characteristics of this cleaning technique, such as being versatile, precise, controllable, lack of waste generation, and environmental friendly process. This laser technique can remove the coating layers without using chemical products and prevents the metal substrate surfaces from defect. This paper reviews the potential of incorporating pulsed Nd:YAG laser and its principals in coating removal for automotive industry with respect to these characteristics.

Determination of Indoor 222 Rn Concentrations Level on Different Room Sizes in Academic Building at Universiti Malaysia Kelantan Jeli Campus

The objectives of this study are to briefly monitor the 222Rn concentration in selected study area and to investigate its correlation with the environmental factors (pressure, humidity and temperature). 222Rn concentrations were monitored in three different sizes of lecture rooms known as BK 6, BK 7 and BK 8 at academic building, Universiti Malaysia Kelantan (UMK) Jeli Campus. Radon monitor known as Sentinel 1030 has been used to collect 210 readings of 222Rn concentration data. Environmental factors for each study areas was analyzed by using Pearson correlation. The average 222Rn concentrations for BK 6, BK 7 and BK 8 were found at 0.29 pCi/L, 0.31 pCi/L and 0.72 pCi/L, respectively. BK 8 with 277.97 m³ obtained higher 222Rn concentrations than BK 6 with 440.98 m³, followed by BK 7 with 292.67 m³. From the results, 222Rn concentration in BK 6 and BK 7 are influenced by temperature and pressure, correspondingly. However, no correlation of environmental factors found in BK 8.

Ablation of Selected Dental Materials Using Er,Cr:YSGG Laser

The effect of Er,Cr:YSGG laser for ablation of commercialized adhesive dental materials were studied using 12 sets of tooth samples. The surface morphology and composition of the tooth samples was observed before and after irradiation using FESEM and EDX. Time dependency of exposure is observed in the tooth sample. Adhesive material Grēngloo produced better ablation on long exposure compared to adhesive material Blūgloo. The ablation effect was also compared between presence and absence of water. The enamel surface produced is highly dependent on the technique used to ablate the adhesive material. Without water, enamel surface appeared roughed and depth of crater was also created. In particular, both materials produce different quality of ablation and reacted differently under different laser parameter and setting.

Investigations of Outdoor and Indoor 222Rn Concentrations Level in Academic Building at Universiti Malaysia Kelantan Jeli Campus

Radon (222Rn) is radioactive gas emanates from soil, rock sand and enter the building through cracks, construction joint, gas in suspended floors and also from the building materials itself. 222Rn gas in high concentrations is hazardous as it can affect the human organ and tissues due to the emission of alpha particles. This study aims to determine the outdoor and indoor 222Rn concentrations in academic building, Universiti Malaysia Kelantan (UMK) Jeli Campus as well as to identify any possible factors influenced the gas progenies. Radon Sentinel 1030 was placed in open space between the lecturer’s rooms and inside closed room (Lecture Hall 4) on the first floor of the building for data collections. The total of 224 data of 222Rn concentrations reading has been collected for outdoor and indoor spaces with 0.5 hours time interval. The outdoor and indoor 222Rn concentrations were found in ranges between 0.23 pCi/L to 0.48 pCi/L and 0.73 pCi/L to 1.13 pCi/L, respectively.

The effects of altitude levels on 222Rn concentration in academic building at Universiti Malaysia Kelantan Jeli campus

Highly continuous exposure to Radon (222Rn) concentrations can affects human health and cause lung cancer. This study aims to briefly monitor 222Rn concentration at different level altitude and to investigate correlation between their environmental parameters sort of temperature, humidity and pressure in indoor space. Lecture rooms known as BK 4 in the first floor and BK 8 in the third floor at academic building Universiti Malaysia Kelantan (UMK) Jeli Campus were selected as the study areas. The total of 210 readings indoor 222Rn concentrations data have been collected for the whole study using Radon Sentinel Model 1030. Average 222Rn concentration in BK 4 and BK 8 were found to have range from 0.36 pCi/L to 0.73 pCi/L and 0.40 pCi/L to 0.93 pCi/L, respectively. 222Rn concentration is higher at BK 8 with height 14.4 meter than BK 4 with height 4.8 meter from the ground. Negative correlations were obtained between 222Rn concentrations over pressure, temperature and humidity at BK 4. Meanwhile, 222Rn concentrations over pressure and humidity at BK 8 have shown positive correlation and negative correlation with temperature.

Variant analysis in coarse grain heat affected zone of low carbon steel

Coarse Grain Heat Affected Zone (CGHAZ) is a part of Heat Affected Zone (HAZ) that affected by heat during welding process. Application of different heat input dramatically varies CGHAZ microstructures without a noticeable changing in prior austenite grain size. The unique coarse microstructure and crack initiated at CGHAZ show there were possibility changes in crystallographic structure which may relate to the variant selection phenomenon. The aims of this study are to find the effects of heat input to the variant selection especially to the biggest grain at CGHAZ, hence correlate to the toughness and properties of the welded steel. The results show that heat input affected the variant selection at the biggest CGHAZ grain of low carbon steel. As heat input increase, grain area was increased and becomes coarser. Variant selection phenomenon present at low carbon steel due to the increase in grain diameter and high angle value. It was found that variant selections had occurred during the transformation.