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PublicationPrediction of PM₁₀ level during high particulate event in Malaysia using modified model(EDP Sciences, 2023)Particulate matter (PM10) is one of the key indicator of air quality index (API) during high particulate event (HPE). PM10 can cause adverse effect on human health and environment; hence, it is important to develop a reliable and accurate predictive model to be used as forecasting tool to alarm the citizen especially during HPE. This study aims to develop a modified Quantile Regression (QR) model to forecast the PM10 concentration during HPE in Malaysia. The performances of three predictive models namely Multiple Linear Regression (MLR), Quantile Regression (QR) and a modified QR models i.e. combination of QR with Relief-based were compared. The hourly dataset of PM10 concentration with other gaseous pollutants and weather parameters at Klang from the year with severe haze event in Malaysia (1997, 2005, 2013 and 2015) were obtained from Department of Environment (DOE) Malaysia. Three performance measures namely Mean Absolute Error (MAE), Normalised Absolute Error (NAE) and Root Mean Squared Error (RMSE) were calculated to evaluate the accuracy of the predictive models. This study found that the Relief-QR model showed the best performance compared to MLR and QR models. The prediction of future PM10 concentration is very important because it can aid the local authorities to implement precautionary measures to limit the impact of air pollution.
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PublicationMetal induced crystallization of polycrystalline silicon germanium: The morphological study between nickel and copper(AIP Publishing Ltd., 2023)In this study, metal induced crystallization technique is used in to obtain the lower temperature point in crystallization. Two different metals with one non-metal configuration as a baseline i.e. SiGe/Ni, SiGe/Cu and SiGe. A simple metal-assisted chemical etching method is used to fabricate the Si nanopillar, with Ag acting as a catalyst. Following by deposition of metal namely nickel (Ni) and copper (Cu) then undergo thermal annealing from 200 ℃ until 1000 ℃ to improve the crystallinity of the Ge layer. Morphological studies of surface area were conducted using scanning electron microscopy (SEM). The results show that the crystallization temperature of SiGe with Ni was obtained at 400 ℃ while the crystallization temperature of SiGe without any metal was obtained at 600 ℃. Meanwhile the crystallinity, for SiGe/Cu only occurs in very low level where the structure did not change until the annealing was conducted at 600 ℃. Based from these result, it is proved that the metal can help lowering the crystallization temperature and improving the defects of SiGe.
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PublicationImplementation of automation system-based model checking for managing imperfect maintenance actions in chemical plant projects(Emerald, 2023)The chemical plant (CP) maintenance industry has been under increasing pressure by process designers to demonstrate its evaluation and information management of model checking (MC) on the durability’s performance and design of plant control instrument. This main problem has been termed as imperfect maintenance actions (IMAs) level. Although IMAs have been explored in interdisciplinary maintenance environments, less is known about what imperfect maintenance problems currently exist and what their causes are, such as the recent explosion in the Beirut city (4 August 2020, about 181 fatalities). The aim of this paper is to identify how CP maintenance environments could integrate MC within their processes. Design/methodology/approach: To achieve this aim, a comprehensive literature review of the existing conceptualisation of MC practices is reviewed and the main features of information and communication technology tools and techniques currently being employed on such IMA projects are carried out and synthesised into a conceptual framework for integrating MC in the automation system process. Findings: The literature reveals that various CP designers conceptualise MC in different ways. MC is commonly shaped by long-term compliance to fulfil the requirement for maintaining a comfortable durability risk on imperfect maintenance schemes of CP projects. Also, there is a lack of common approaches for integrating the delivery process of MC. The conceptual framework demonstrates the importance of early integration of MC in the design phase to identify alternative methods to cogenerate, monitor and optimise MC. Originality/value: Thus far, this study advances the knowledge about how CP maintenance environments can ensure MC delivery. This paper highlights the need for further research to integrate MC in CP maintenance environments. A future study could validate the framework across the design phase with different CP project designers.
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PublicationStatistical optimization of adsorption process for removal of Methylene blue using Durio Zibethinus Murr shell(AIP Publishing Ltd., 2023)Adsorption of methylene blue (MB) was investigated using physically prepared Durio Zibethinus Murr shell activated carbon (DZMAC). Response surface methodology (RSM) statistical technique was used to optimise the preparation conditions: activation power, activation time, and CO2 flow, with the percentage of MB dye removal and DZMAC yield as the targeted responses. Based on the central composite design (CCD), two empirical models were developed and validated by applying ANOVA analysis incorporating interaction effects of three variables using RSM to the two responses. The optimum conditions for preparing DZMAC for adsorption of MB dye were found as follows: activation power of 666-Watt, activation time of 2.83 minutes, and CO2 flow of 100 cm3, which resulted in 70% of MB dye removal and 25.21% of DZMAC yield. Experimental results obtained agreed satisfactorily well with the model predictions.
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PublicationMonitoring of three stages of paddy growth using multispectral vegetation index derived from UAV images(Elsevier, 2023)Paddy cultivation in Malaysia plays a crucial role in food production, with a focus on improving crop quality and quantity. With current national self-sufficiency levels ranging between 67 and 70%, the Malaysian government intends to produce higher-quality crops and boost agricultural production. However, the prominent paddy-producing state of Kedah has witnessed a decline in yields over the years. To address this, the study explores the effectiveness of unmanned aerial vehicles (UAVs) equipped with vegetation indices (VIs) for monitoring paddy plant health at various growth stages. Researchers acquired aerial imagery during two seasons in 2019, capturing three distinct growth stages: tillering (40 days after sowing), flowering (60 days after sowing), and ripening (100 days after sowing). These stages represent critical points in the paddy plant's life cycle. Agisoft Metashape software processed the images to extract VIs data. The study found that the Normalized Difference Vegetation Index (NDVI) and Blue Normalized Difference Vegetation Index (BNDVI) exhibited over 90% similarity. In contrast, the Normalized Difference Red Edge Index (NDRE), utilizing near-infrared and red-edge light reflections, demonstrated a unique relationship. NDRE outperformed NDVI and BNDVI with an R-squared value of 0.842, showcasing its superior accuracy, especially for dense crops like paddy plants sensitive to subtle changes in vegetation. In conclusion, this research highlights the potential of UAV-based VIs for effectively monitoring paddy plant health during different growth stages. The NDRE index, in particular, proves valuable for assessing dense crops, offering insights for precision agriculture and crop management in Malaysia.