Theses & Dissertations

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Now showing 1 - 5 of 53
  • Publication
    Optimization of activated carbon preparation from Sea Mango fibrous shell (cerbera odollam) functionalized with deep eutectic solvent (DES) for carbon dioxide (CO₂) adsorption (Restricted)
    (Universiti Malaysia Perlis (UniMAP), 2018)
    Nurul Zufarhana Zulkurnai
    In recent years, carbon dioxide (CO2) emission has become a major concern as the amount of the emitted gas significantly increases annually. Consequently, this phenomenon contributes to global warming. Several CO2 capture methods, including chemical adsorption by activated carbon (AC) have been proposed. However, the production cost of commercial AC is relatively high. In this study, the AC was prepared from sea mango (Cerbera odollam) in order to reduce the production cost of AC. The preparation of AC has been optimized by using Response Surface Methodology (Box - Behnken Design). The optimized preparation parameters were found to be 53.75% of acid concentration, 519.75oC of carbonization temperature and 2.28 hours of activation time which resulted in 861.95m2/g of BET surface area. The optimized sea mango AC (OSMAC) has been impregnated with Deep Eutectic Solvent (DES) at 1:2 solid-toliquid ratio in order to increase the efficiency of CO2 capture and on the same time lowering the cost comparing to impregnation of amine and an ionic liquid (IL). DES is composed of choline chloride (ChCl) and urea with ratio 1:2 of ChCl to urea. The BET surface area of DES activated carbon (DESAC) is 585.75 m2/g. The activation process was further confirmed by the presence of new bond of theN-H band and C-Cl stretch at peak 1635.19 cm-1 and 628.24 cm-1 respectively. Both of these bonds are suspected to be contributed by the ChCl and urea from the DES. The reduction of BET surface area was approximately 40% after DES impregnation proved that DES molecule successfully attached to the surface of the AC. The result was further confirmed by SEM images which showed most of the pore of the AC has been occupied by the DES. The EDS test also confirmed that the increasing amount of N element from 6.1% to 18.4% after being impregnated with the DES. The performance of the AC on the CO2 adsorption was obtained through breakthrough time curves and adsorption capacity. Three tests were conducted including different types of adsorbent, difference adsorbent dosage and different inlet flow rate. It was found that the DESAC has better CO2 adsorption capacity compare to the OSMAC which is 39.40 mgco2/gsol and 33.46 mgco2/gsol respectively. This is due to the increment of active side contributed from the DES which allows more CO2 molecule to be attached to the DESAC. The increment of active site has been illustrated in the mechanism interaction of CO2 which suggested that 6 molecules of CO2 able to be captured by 1 molecule of DES. For the adsorbent dosage, the increment weight of the AC has increased the CO2 adsorption capacity as more pores and active sites is available, thus increasing the chance for CO2 attachment. In term of flow rate, the increment of flow rate has reduced the breakthrough time. This is due to the high amount of CO2 molecule supplied per minutes during high inlet flow rate, hence causing the AC to be saturated faster. Throughout this study, it is confirmed that the functionalization of DES on the AC has enhanced the CO2 adsorption compare to the OSMAC.
  • Publication
    Imputatation methods for filling the long interval of missing observations in air pollution data and meteorological dataset (Restricted)
    (Universiti Malaysia Perlis (UniMAP), 2018)
    Nur Afiqah Zakaria
    Missing data always happened in real time processing applications that are highly depending on data and the example of time series data in environmental field is air pollution data. These data were obtained from the automated monitoring stations and usually contained missing observations due to the routine maintenance, human error, machine failure, change in monitors siting and other factors that can lead to missing data. The problem that can arise from missing data are error in measurement, insufficient sampling, bias due to systematic difference between observed and unobserved data and fault in data acquisition. In this study, hourly monitoring records of four air pollution data (PM10,CO, SO2, NO2) and three meteorological data (ambient temperature, wind speed and humidity) for Gombak (from year 2000 to 2008) and Klang (from year 2000 to 2009) were used. From these dataset, the data that contain the lowest missing data and the most complete data were chosen as the reference data. The dataset that were used as reference data was Klang and Gombak in 2003. The simulation of missing data in this study was designed based on the real trend and pattern of missing data in Malaysia. The dataset were simulated into four percentages of missing data i.e 5%, 10%, 15% and 20%. Six single imputation methods (series mean, mean nearest neighbor, expectation maximization, linear interpolation, 0.2 and 0.3 exponential smoothing and 3 and 5 moving average) and markov chain monte carlo were applied in this simulation study. Then, the goodness of fit of these imputation methods was described by using four performance indicators (Mean Absolute Error, Root Mean Squared Error, Index of Agreement and Prediction Accuracy). Overall, Expectation Maximization (EM) was found out to be the best imputation method to replace the long gap of missing data, meanwhile series mean imputation method was the worst imputation method.
  • Publication
    Assessment and prediction of PM₁₀ concentration during haze event in Malaysia using quantile analysis
    (Universiti Malaysia Perlis (UniMAP), 2024)
    Nur Alis Addiena A Rahim
    Haze event in Malaysia occurs typically during the summer monsoon season. Consequently, high atmospheric particles, particularly PM₁₀, were recorded mainly by transboundary air pollution from the neighboring country, affecting human health and the environment. The air pollutants were widely forecasted in various studies previously, especially PM₁₀. However, there was a lack of research conducted specifically during haze events. Therefore, this research aims to develop a reliable modified quantile regression (QR) forecasting model for the next-day (PM₁₀+24), the next-two-day (PM₁₀+48), and the next-three-day (PM₁₀+72) of PM₁₀ levels during a haze event. The development of a PM₁₀ prediction model specifically for haze events play a crucial role in managing and mitigating the impacts of haze on society, making them as essential tools in air quality management and decision-making. Hourly PM₁₀, air quality parameters, and weather parameters datasets at Klang, Melaka, Pasir Gudang, and Petaling Jaya during historical haze events in 1997, 2005, 2013, and 2015 are obtained from the Department of Environment (DOE) Malaysia. The locations were chosen due to their susceptibility to pollution transported from the Sumatra region, being situated on the west coast of peninsular Malaysia Peninsular. The mean value for each year at all location exceeded the Recommended Malaysian Ambient Air Quality Standard (RMAAQG), except for at Pasir Gudang in year 1997 and 2005, where the mean recorded are 47.72 and 46.59 μg/m3, respectively. Three feature selection methods (weight by Relief, weight by correlation, and weight by principal component analysis (PCA) along with quantile regression (QR) and multiple linear regression (MLR) were implemented in this study. The performance of modified QR model was evaluated by using several performance indicators namely Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) and Normalized Absolute Error (NAE). The modified QR model i.e. QR-Relief, QR-PCA and QR-Correlation models were proven as the best method at all locations and prediction time. In Klang, QR-Relief was chosen for PM₁₀+24 (with percent reduction error of approximately 21.5%) and PM₁₀+72 (with percent reduction error of 11.6%) meanwhile for PM₁₀+48 prediction, the QR-Correlation was selected with percent reduction error of 17.4%. QR-PCA was chosen as the best prediction model for all three days predictions in Melaka with error reduced by 2.08%, 0.69%, and 0.88%, for PM₁₀+24, PM₁₀+48, and PM₁₀+72, respectively. In Pasir Gudang, QR-Relief performed the best for all three days predictions with error reduced by 27.6% until 31.1%. In Petaling Jaya, QR-Relief outperformed other models for PM₁₀+24 (with percent error reduction of 16.5%). Meanwhile, QR-Correlation is the model with the best performance for PM₁₀+48 (with error reduced by 10.9%) and PM₁₀+72 (with error reduced by 15.9%) in Petaling Jaya. Feature selection helps identify and include only the most relevant variables in the model which eventually improve the models accuracy. The verification of the models using the unseen dataset from 2019 proved that the model can be deployed in the real-world PM₁₀ data. This proposed model can be used as a tool for early warning alerts to the local authorities to mitigate and plan preventive measures.
  • Publication
    Removal of azo and anthraquinone dye from textile wastewater using ozone-based advanced oxidation processes
    (Universiti Malaysia Perlis (UniMAP), 2018)
    Siti Nasuha Sabri
    Ozonation (OJ) and advanced oxidation processes (AOPs) involving ozone in combination with persulphate (OJIS2082-) has been considered as an emerging technology to treat dyes and dyestuff industrial effluents. However, the performance of dye removal remains unclear. Therefore, this research aim to evaluate the performance of two treatment methods by employing OJ and OJ/S2082- for synthetic dye wastewater, consist of azo Reactive Red 120 (RR120) and anthraquinone Reactive Blue 19 (RB 19). The main objective of the research are to compare the performance of 0 3 and 0 3/S2082-processes for colour, and chemical oxygen demand (COD) removal for two different types of dye. The experiments of 0 3 and OJIS2082- process were conducted in a semibatch reactor originated from cylindrical glass reactor. For better understanding of the treatments, the research focused on the most significant parameter that govern the treatments such as initial dye concentration, contact time, pH and S2082- dosage. Furthermore, the performance is compared by evaluating the key parameters such as colour and COD. The degradation and oxidation products are characterized based on the change in ultraviolet-visible (UV-Vis) and Fourier transforms-infrared (FT-IR) spectra. In addition, the optimization of process parameters was performed by Design Expert 7.1 Software. This study has found that, the OJ/S2082- advanced oxidation treatment provides good performances in the colour removal of the RR120 in water. The change in the UV-Vis and FT-IR spectra indicated the cleavage of the dye structure and formation of intermediates. The initial S2082- dosage, dye concentration and pH play an important role in the generation of hydroxyl and sulphate radicals for the dye degradation. The results of this investigation show that, the decolourisation was strongly depending on initial S2082 dosage. The decolourisation efficiency increased with increasing S2082- dosage and reaction time. While, decolourisation efficiency decreased with raising the initial dye concentration.
  • Publication
    Influence of vertical earthquake on the variations of axial load ratio of reinforced concrete buildings
    (Universiti Malaysia Perlis (UniMAP), 2016)
    Awang @ Abdul Halim Taib
    Current earthquake engineering field ignores the repeated and vertical ground motion in design and analysis of the structure system even though in actual condition these two phenomena impose the significant effect to the structural system. This gradually changing due to the increase in near source record obtained recently, coupled with field observation confirming the possible destructive effects of high vertical vibration. The aim of this study is to assess the behaviour of regular and irregular reinforced concrete frames due to multiple earthquakes with vertical component. The structural response quantities are expressed in term of variation of axial load. Axial load ratio obtained by dividing axial load in column induced by combined horizontal and vertical component of ground motion (VHGM) to axial load in column induced by horizontal component of ground motion (HGM) load. Obtaining vertical spectral shape by scaling the horizontal ground motion using V IH ratios of 2/3 rule as suggested by many codes can be seriously underestimate action on structures located near earthquake sources and overestimates action in far field regions. The frame models are subjected to the horizontal and vertical ground motions with various peak ground acceleration ratios between horizontal and vertical ground acceleration (V /H) ranging from 0.3 to 1.9 using RUAUMOKO software. This study found out that vertical ground motion showed significant effect to the reinforced concrete building with maximum axial load ratio of 54 for regular and 6 for irregular rc frame. Eight storey regular models showed typical graph with the shape of number three for plotted axial load ratio against height. Axial load ratio values was almost equal to one at base, mid and top floor but increases at one fourth and three fourth of the building height. Irregular model showed typical graphs with higher axial load at lower floor and decreased along the heights.
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