Pusat Pengajian Kejuruteraan Awam - Tesis

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Kajian Penghasilan Dan Komposisi Enap Cemar Dari Loji-Loji Olahan Air Di Negeri Perak Dan Kesesuaian Sebagai Bahan Binaan
(2003-05)
Shuib, Nor Lila
The objectives of the study are to estimate the quantity of sludge produced, to identify the characteristics of raw water and sludge, and to identify the composition of elements in the sludge with the possibility of using it as a useful material in the future. In order to meet these objectives, several tests were conducted on raw water samples and sludges. These include test on pH, turbidity, total suspended solids, moisture content, specific gravity and composition of elements in the sludge.
Kajian Kestabilan Cerun Menggunakan Kaedah Berkebarangkalian Di Lombong Tembaga Mamut, Ranau, Sabah
(2003-02)
Mohd Yusof, Mior Termizi
Suatu kajian kestabilan cerun telah dijalankan di cerun-cerun sebuah lombong dedah iaitu Lombong Tembaga Mamut yang terletak di Ranau, Sabah. Geologi dan permineralan dalam batuan telah dikaitkan dengan kestabilan cerun lombong. Mod kegagalan telah dikenalpasti serta kajian kestabilan yang lalu telah dilihat semula. Dua jenis kegagalan iaitu yang dikawaloleh struktur geologi dan yang tidak dikawaloleh struktur geologi telah dikenalpasti. Beberapa analisa kestabilan cerun berketentuan telah dirujuk semula tetapi kaedah berkebarangkalian digunakan untuk menganalisa cerun-cerun di Lombong Tembaga Mamut.
Assessment of the flow characteristics of a dam physical model with anti-vortex structure using computational fluid dynamics
(2023-05-01)
Thiennieesh A/L Manogaran
Dams are structures that are being used to oppose or halt the flow of water in a stream or river. Unfavourable flow characteristics in the dam can cause problems such as fluctuation in pressure, loss in discharge capacity as well as problematic flow conditions in tunnels ad turbines. This research describes the physical modelling performed on the physical model of a dam reservoir with a distorted scale of 1:100. Particle Image Velocimetry (PIV) approach was implemented since it has evolved into one of the most prominent non-intrusive flows measuring techniques and was able to measure flow parameters such as velocity and discharge which had a good data agreement with Nixon Streamflow Velocity Meter. Free-surface vortices (FSV) were also detected through velocity vector instantaneously. CFD modelling enables to analyse flow patterns in the model, such as free-surface vortices. The model of the 1:100 scale dam reservoir was generated, computationally meshed, and modelled in FLUENT under ANSYS 2019 R3 at two different water levels to observe the FSV formations. To mitigate those FSV formations, anti-vortex plates with two distinct plates—square and wedge—were used. From the findings square plates outperform wedge plates because square it lowers the speed of a fast-flowing fluid and reduces it into a laminar flow rather of a turbulent flow, which benefits vortex class deterioration. Data from the simulation and experimental shows a strong agreement in terms of velocity less than 20%. From this study, the modification could be adapted to avoid the FSV formation in the real dam model when designed under suitable guidelines for vortex structures.
Risk perception and travel behavior change during covid-19 pandemic in Malaysia
(2023-06-01)
Surachai A/L Airak
The emergence of the COVID-19 pandemic has disrupted people’s travelling due to the restrictive policies implemented by governments around the world. This, in return, has caused a chain reaction and disrupted different sectors. Although there have been studies on the impact of COVID-19 on travel behaviour in Malaysia, little has been carried out on two different periods of the same pandemic. Therefore, this study aims to determine the risk perception of Malaysians towards COVID-19 and changes in travel behaviour focusing on two phases of the pandemic. Quantitative method involving a national cross-sectional survey was conducted online to collect data from two separate periods namely before and after interstate travel was allowed. The first survey was carried out for approximately three months (June 7th, 2021, to August 27th, 2021), and managed to obtain 2129 respondents; meanwhile, the second period took around four months (October 18th, 2021, to March 9th, 2022), and managed to obtain 2217 respondents. . The questionnaire comprises socio-demographics, experience with COVID-19, risk perception of COVID-19, and trip frequency on several activities during the pandemic. Firstly, a descriptive analysis was done to obtain information about the respondents. Next, Mann-Whitney U was conducted to determine whether there were statistically significant differences between the sociodemographic factors for the respondents in the first and second surveys. Results show no significant difference in socio-demographic factors except for the level of education.. A comparison was also made for travel behaviour. Results for both surveys showed that the frequencies across all activities significantly decreased in the second phase of data collection compared to the first phase. The findings also showed that risk perception also varies between both periods. Finally, structural equation modelling (SEM) was used to obtain the significant factors affecting risk perception, precautionary measures, travel risk perception, and travel behaviour. During the first survey, SEM found that occupation positively affected risk perception. Precautionary measures were affected by occupation and risk perception; meanwhile, travel risk perception was affected by precautionary measures and risk perception. Finally, travel behaviour was influenced by occupation and risk perception. During the second survey, risk perception was affected by occupation. The frequency of precautionary measures was affected by occupation and risk perception. Travel risk perception was not affected by any variables. In addition, travel behaviour was affected by occupation and risk perception. By understanding the influences of risk perception and occupation, alongside other factors on other variables, the government could get an idea of possible effects post-crisis, such as the transition towards a more virtual setting in certain sectors, which will decrease mobility, and possible change in transport modes once the pandemic is over. This, therefore, could help them manage and distribute necessary resources to rectify the negative impacts brought by COVID-19.
Coagulation-flocculation process by tin tetrachloride (sncl4), rubber seed, polyacrylamide (pam) and sedifloc in landfill leachate treatment
(2023-09-01)
Siti Fatihah Binti Ramli
The goal of this study is to assess the effectiveness of tin tetrachloride (SnCl4), rubber seed (RS), polyacrylamide (PAM), and Sedifloc as coagulants/coagulant aids for the removal of colour, COD, suspended solids (SS), and UV254 from high strength leachate. Divalent and trivalent metal-based coagulants were the primary focus of earlier research on leachate treatment. Tetravalent coagulants have not yet been extensively studied for application in leachate treatment. The same case goes for RS, PAM and Sedifloc. There are no reported studies to date on the use of RS for the treatment of high-strength leachate. The leachate samples in this study were collected from the aged Alor Pongsu landfill site located in Alor Pongsu, Perak, Malaysia and multi-series of coagulation-flocculation experiments were conducted in standard jar test procedures. The results found that, the optimum condition for SnCl4, RS, PAM and Sedifloc when used alone was rapid mixing of 220rpm-4 minutes, 120 rpm-10 minutes, 180 rpm-8 minutes,220 rpm-8 minutes; slow mixing of 60 rpm-30 minutes, 60 rpm-20 minutes, 60 rpm-30 minutes, 60 rpm-20 minutes; settlement time of 40-45 minutes; optimum dosage (10,000 mg/L, 6000 mg/L, 1000 mg/L, 500 mg/L); optimum pH (pH 8, pH 3, pH 2, pH 2), respectively. When SnCl4 was used alone, the removals obtained for colour, SS, COD and UV254 were 98.9%, 100%, 74.5%, and 95.7%, respectively. However, RS, PAM and Sedifloc were found ineffective when used alone. When used as the coagulant aid, the obtained removal percentages were comparable to SnCl4 alone. The dosage of SnCl4 was reduced from 10,000 mg/L to 8,000 mg/L when RS was used as a coagulant aid and to 6000 mg/L with the usage of PAM and Sedifloc. Characteristics of the sludge supported that the main mechanism involved for SnCl4 was charge neutralization and bridging for RS, PAM and Sedifloc. It was also found that the functional groups such as amine, carboxyl and hydroxyl are the active functional groups components that are responsible for the effective coagulation and flocculation activities. It was found from the study that 6000 mg/L SnCl4 in the presence of 100 mg/L Sedifloc is the best option in removing pollutants in leachate and also improves the characteristics of sludge after the treatment. Therefore, SnCl4 use in conjunction with Sedifloc was chosen as the best condition for the treatment of Alor Pongsu and other equivalent leachates.

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