Mazlan Mohamed

Wood is a naturally occurring renewable resource widely used in various industries, including in construction, packaging, furniture, and paneling. In Malaysia, 80% of furniture products are made from wood, making it a crucial material in this sector. Laser cutting is an advanced machining technique that enhances precision and minimizes material waste, yet its thermal effects, particularly the heat-affected zone (HAZ), remain a challenge. This study investigates how laser cutting parameters—including the laser power, traverse speed, and focus position—affect HAZ formation in two fast-growing Malaysian wood species, Acacia mangium and Azadirachta excelsa. This research seeks to determine the optimal laser settings that minimize HAZ dimensions while maintaining cutting precision. A diode laser cutting system was used to analyze the effects of three laser power levels (800, 1500, and 2400 mW), three traverse speeds (2, 5, and 10 mm/s), and three focus positions (on-focus, +0.2 mm, and −0.2 mm). We employed statistical analysis, including a two-way ANOVA, to assess the significance of these parameters and their interactions (p < 0.001). The results indicate that a higher laser power and slower speeds significantly increase the HAZ’s width and depth, with Azadirachta excelsa exhibiting a greater HAZ width but shallower penetration compared to Acacia mangium. A slight above-focus position (+0.2 mm) reduces the HAZ’s width, whereas a below-focus position (−0.2 mm) increases the HAZ’s depth. The optimal parameters for minimizing HAZ dimensions while ensuring efficient cutting were identified as a 1500 mW laser power, a 10 mm/s traverse speed, and an on-focus position (0 mm). This study provides practical insights into laser parameter optimization for tropical wood species, contributing to improved precision in laser machining and sustainable wood processing practices. These findings support industries in adopting advanced, high-quality laser cutting techniques tailored to fast-growing wood resources.

In this paper, the modeling of an industrial robot is presented. The simulation of an industrial robot is carried out using the ADAMS multibody system. The computer-aided design model of an industrial robot is imported into ADAMS. The imported model in ADAMS is prepared for the simulation by adding markers or frames to the rigid bodies of an industrial robot. The relationship between the rigid bodies is established by applying constraints in ADAMS. The STEP function from the function builder is used to move the rigid bodies of an industrial robot. The STEP function is an expression that uses the initial and final conditions to create a smooth motion. The joint limits of an industrial robot are specified in the STEP function to trace the path of an end-effector, which represents the workspace of an industrial robot. Furthermore, the pose of an industrial robot using STEP expression is investigated in the postprocessor.

Hydrological modeling required essential input data such as river bathymetry, discharge, topographic and floodplain elevation values, manning’s n values, and precipitation. In this study, river bathymetry and spatial distribution of precipitation were focused because of challenges in their estimation and associated uncertainties. These input data are also important in accurate flood risk and vulnerability assessment. Previous studies developed several models for their estimation using remote sensing and GIS. However, further improvement is required for their accurate estimation. This study will be helpful in accurate spatio-temporal estimation of these two input data. Furthermore, it was suggested the use of machine learning approaches to handle big data obtained from satellite images for further improvement in the spatio- temporal estimation.

Environmental impact assessment is essential to meet the objectives of sustainable product design. The environmental impact should be measured at the initial stages of product design to minimize the impact. In this paper, we demonstrate the application of a computer-aided design (CAD) tool to measure the environmental impact during the design stage. SolidWorks software uses the Life Cycle Assessment (LCA) model to measure the environmental impact such as energy consumption, carbon footprint, and air-water pollution. The spur gear model is used to demonstrate the process of assessing environmental impact using the CAD tool. The input parameters such as material, manufacturing process, region, transportation method, and product usage play an essential role in the environmental impact. The results indicate that the environmental impact can be reduced by optimizing the parameters by selecting alternatives using the CAD tool at the initial design stage.

Diesel engines are one of the most popular reciprocating engines on the market today owing to their great thermal efficiency and dependability in energy conversion. Growing concerns about the depletion of fossil resources, fluctuating prices in the market, and environmental issues have prompted the search for renewable fuels with higher efficiencies compared with conventional fuels. Fuel derived from vegetable oils and animal fats has comparable characteristics to diesel fuel, but is renewable, despite being manufactured from various feedstocks. Nevertheless, the direct use of these fuels is strictly prohibited because it will result in many issues in the engine, affecting engine performance and durability, as well as emissions. To make biofuels as efficient as fossil fuels, it is essential to alter their characteristics. The use of emulsification techniques to obtain emulsified biofuels is one of the many ways to modify the fuel characteristics. Emulsification techniques allow for a decrease in viscosity and an increase in atomisation during injection. To date, emulsification techniques have been studied less thoroughly for use with vegetable oils and animal fats. This article will discuss the preparation and characterisation of emulsified biofuels made from vegetable oils and animal fats. This current paper reviewed research studies carried out on different emulsification techniques for biofuels used in diesel engines.

Every year, high school students response to choosing a science stream has indicated a declining pattern. It may be due to the lack of technical application of science that students cannot foresee, thus preventing them from having a clear vision of how science and technology could greatly help daily human life. The study aims to assess the knowledge of high school students through STEM education via a project-based learning method using the hydroponic kit. Seventy students from a government school in Kota Bharu, Kelantan, Malaysia, participated in this study. The questionnaire was then evaluated based on the scores and displayed improvement. The mean score for the pre-test of general knowledge was M=3.8857, SD=1.41977, and then it increased to M=6.1857, SD=1.21932 for the post-test. In addition, the mean score for the pre-test of hydroponic system advantages was M=6.2000, SD=1.93068, which increased to M=8.8286, SD=0.65875 for the post-test. Meanwhile, the mean score for the pre-test of disadvantages of the hydroponic system was M=7.2571, SD=2.21121, subsequently increasing to M=9.4286, SD=0.73369 for the post-test. Finally, the mean score for the pre-test of practical knowledge was M=9.3429, SD=2.51307, and then increased to M=15.0571, SD=1.84065 for the post-test. Students’ responses to the tests indicated that their interest in the field of science has increased through their involvement in the hydroponic kit project.