Vol. 56 No. 4 (2024)

Back Matter

Malaysia has experienced rapid urbanization since Industrial Revolution (IR) 4.0, which has resulted in significant changes in energy consumption and CO2 emissions. Its urban areas are characterized by high population densities, which has led to increased demand for transportation and construction activities, thereby enhancing the carbon footprint of Malaysia. Yet, the country has also set ambitious targets for reducing its carbon footprint and has committed itself to the Paris Agreement on climate change. The government has set a target to reduce the intensity of greenhouse gas emissions by…

Groundwater-exposed liquid clay soil (CL) makes foundations unstable. This study used recycled rice husk ash and treated clay soil exposed to groundwater with low-cost, environmentally friendly materials. This paper presents a recent prediction of three equations that link the plastic index to soil strength, cohesion, and the bearing capacity of a foundation. This prediction takes into account the soil’ characteristics before and after treatment, as well as the cumulative load until failure. It creates four models before and after treatment, as well as a different time period after treatment,…

Power systems are run by combining different energy producers while the demand serves as the system’s energy user and covers all of the non-flexible and flexible loads, including electric vehicles (EVs). This study investigated the trip pattern impact of EVs, utilizing the Orca Algorithm (OA), in optimizing power production, applied to the IEEE-62 bus system as a model. Considering one-way and two-way trips over several categories of typical roads, the mobility of 14,504 EVs, divided into four driving patterns (Mobility 1-4), was estimated. Approximately 2,933 EVs traveled for…

Accurate data acquisition is crucial in embedded systems. This study aimed to evaluate the data acquisition ability of the ESP32 Analog to Digital Converter (ADC) module when combined with the I2S module to collect high-frequency data. Sine waves at various frequencies and white noise were recorded in this mode. The recorded data were analyzed by the fast Fourier transform (FFT) to assess the accuracy of the recorded data and evaluate the generated noise. Digital filters are proposed to improve the quality of the collected signals. A 2D spectrogram imaging algorithm is proposed to convert the…

Chemical etching is a crucial process in materials science that involves controlling material removal through chemical reactions. It offers precise surface manipulation for various applications. In this study, the focus was on investigating the influence of temperature and etching solution concentration on the corrosion rate and surface roughness of aluminum alloy 2024. A range of temperatures (from 35 to 65°C) was selected with increments of 5 °C. Three concentrations (9, 20 and 29 Be) of the etching solution (ferric chloride) were examined. The experimental results revealed that both the…

Bituminous pavements are designed to withstand vertical compressive strain at the top of the subgrade layer and horizontal tensile strain at the bottom of the bituminous layer. The modulus value of all the layers acts as an important parameter for accurate pavement designing. As the value of the granular layer’s modulus is a function of deviatoric stress and confinement pressure, this research studied the influence of bituminous and soil layer properties on the modulus of the granular layer hypothesized to follow E = k1 θ^(k2 ), where θ represents the stress invariant and k1 and k2 denote…

Although Indonesia has set a target for increasing the use of renewable energy for electricity generation, the use of coal as a source of energy will still dominate at least until 2040. Sulfur dioxide (SO2) along with other gases and particulates released from the use of coal in coal-fired power plants (CFPPs) may cause air pollution. The use of seawater, an abundant source of absorbent in a maritime country such as Indonesia, in flue gas desulfurization (SWFGD) absorbers, is an economical option for treating SO2 in an absorption tower compared to other alkaline chemicals, e.g. limestone…

Solid-state lighting based on LEDs is used in various applications, including display, communications, etc. However, the high junction temperature is still challenging due to the LED chip’s reduced light output and lifetime. To face this challenge, a thermal study was done to determine junction temperature TJ of a multi-led chip package. Then, a sensitivity analysis of different materials was performed using the Sobol method to identify the parameters that most influence the junction temperature. To calculate the probability of failure of the model, the FORM-SORM and Monte Carlo methodologies…

Increasing population growth has resulted in increased vehicle ownership and the need for parking facilities, including in basements. This study aimed to explore the efficacy of palm shell activated carbon panels in reducing CO, NO2, HC, Pb, and noise. The experiment was conducted in a 4 m x 3 m x 2.1 m room using three treatments: without installed activated carbon panels; with 1 cm x 20 cm x 20 cm activated carbon panels; and with 2 cm x 20 cm x 20 cm activated carbon panels. During the measurement, three motorcycles were turned on and kept in idle mode. The concentrations of CO, NO2, HC,…

This research was motivated by the abundance of biomass plantations in Indonesia. Accumulated biomass waste will cause environmental problems. Biomass processing can resolve this issue, by producing functionally and economically valuable products. The purpose of this research was to increase the value of biomass by processing it as liquid smoke through pyrolysis and then proceeding to the purification stage. The purification method applied in this research was a combination of distillation and adsorption processes using natural zeolite. The variables of this research were: two types of…