Nor Hakimin Abdullah

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.

Larvicidal Effectiveness of Azolla pinnata against Aedes aegypti (Diptera: Culicidae) with Its Effects on Larval Morphology and Visualization of Behavioural Response

Dengue is vector-borne diseases with 390 million infections per year extending over 120 countries of the world. Aedes aegypti (L.) (Diptera: Culicidae) is a primary vector for dengue viral infections for humans. Current focus on application of natural product against mosquito vectors has been the main priority for research due to its eco-safety. The extensive use of chemical insecticides has led to severe health problems, environmental pollution, toxic hazards to human and nontarget species, and development of insecticide resistance on mosquitoes. Azolla pinnata is an aquatic fern and predominantly used as feed in poultry industry and as fertilizer in agricultural field for enhancing the fertility of rice paddy soil. The present study was conducted to explore the larvicidal efficacy of A. pinnata using fresh and powdered form against late third-stage larvae (6 days, 5 mm in larvae body length) of Ae. aegypti (L.) (Diptera: Culicidae). The larvicidal bioassays were performed using World Health Organization standard larval susceptibility test method for different concentration for powdered and fresh A. pinnata. Powdered A. pinnata concentration used during larvicidal bioassay ranges from 500ppm to 2000ppm; meanwhile, fresh A. pinnata ranges from 500ppm to 9,000,000 ppm. The highest mortality was at 1853 ppm for powdered A. pinnata compared with fresh A. pinnata at 2,521,535 ppm, while the LC50 for both powdered and fresh A. pinnata recorded at 1262 ppm and 1853 ppm, respectively. Finally, the analysis of variance (ANOVA) showed significant difference on Ae. aegypti larval mortality (F=30.439, df=1, p≤0.001) and concentration (F=20.002, df=1, p≤0.001) compared to powdered and fresh A. pinnata at 24-hour bioassay test. In conclusion, the powdered A. pinnata serves as a good larvicidal agent against Ae. aegypti (L.) (Diptera: Culicidae) and this study provided information on the lethal concentration that may have potential for a more eco-friendly Aedes mosquito control program.

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.

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.