Universiti Teknologi Malaysia - Research Data

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The application of lattice gas automata for simulating polymer injection porous media
(Universiti Teknologi Malaysia, 2006) Fathaddin, Muhammad Taufiq
The simulation of polymer displacement in a reservoir is one of the important techniques in petroleum engineering that is used to predict the performance of oil production. Modeling of polymer flow through a porous medium is often derived by a macroscopic scale approach. In order to gain better insight of the polymer flow, a pore scale (mesoscale) model is applied in this thesis to determine the macroscopic properties. The objectives of this research are to develop the Frisch-Hasslacher-Pomeau (FHP) III models of lattice gas automata to simulate microscopic polymer and oil flow for the study of macroscopic properties of adsorption, gelation and polymer displacement phenomena. In the single-phase flow simulation, collision rules of interactions between polymer and solid material for adsorption and gelation processes were proposed. Correlations between various macroscopic properties such as polymer concentration, porosity, surface length, pore width were obtained. In general, the lattice gas automata simulations were in good agreement with previous studies, where the differences between them were between 2.0% to 17.4%. In the two-phase flow simulation, the displacement mechanism for various mobility ratio and adsorption rate was estimated. The change of saturation in dead-end pores during the displacement was analyzed. The results of the two-phase flow simulations were in good agreement with those of laboratory experiments, where differences of all parameters were between 3.1% to 18.4%. The computation time is a crucial factor influencing the feasibility of a mesoscale model application in simulating large porous media. Due to the nature of lattice gas automata, the simulation can run using parallel computers effectively. The use of parallel computers is able to reduce the computation time problem. In this thesis, a parallel computation technique has been proposed to run the lattice gas automata simulation. A cluster system and standalone computers were used to simulate communicating and non-communicating flow in porous media, respectively. The results of the parallel simulations were in good agreement with those of single simulations, where maximum difference of all parameters was 3.93%. The computation time was reduced by a factor that ranged from 1.9083 to 14.3411.
Internal service quality in the Malaysian telecommunication industries
(Universiti Teknologi Malaysia, 2007) Mohd Yusoff , Ainan
Internal service quality reflects the service quality of an organization. The telecommunications industry, facing rapid technological changes and varied customer demands, nonetheless, would find this approach useful in attaining the service quality improvements. The Service Profit Chain concept was adapted to show the relationship between internal customer service quality and internal customer satisfaction (employee satisfaction). Thirty branches or service centres of telecommunications companies participated in the survey, of which 182 of 399 (45.61%) respondents returned the questionnaires. The survey questionnaire was constructed, based on the SERVPERF. The range of scale from one to eight was selected to give the respondents a greater differentiation in the responses, as well as to avoid potential problems in interpreting purely verbal answers. The resultant dimensions from this study were interpersonal relationship, internal customer orientation, internal support systems, work climate, adequate tools, and rewards and recognitions. The results of the study provided the basics of the internal service quality requirements for the telecommunications industry in Malaysia. Interpersonal relationship was found to be the most important dimension, proving that the Malaysian telecommunications companies need to look into this aspect for internal service quality improvements. The significance of using the mean was to show the degree of importance of the dimensions, as well as the level of internal customer satisfaction. The overall internal customer service quality and employee satisfaction for the industry were average. The study carried out could provide a benchmark for service quality improvements in the telecommunications companies, so that eventually customer satisfaction and the resultant profitability could be attained
Mechanical performance of carbon fibre reinforced vinyl ester composite plate bonded concrete exposed to tropical climate
(Universiti Teknologi Malaysia, 2007) Abu Hassan, Shukur
Most of the past and recent short-term and long-term experimental studies on Fibre Reinforced Polymer (FRP) plate or laminate system bonded to reinforced concrete members have shown an improvement in terms of mechanical performances but the findings on the bond durability characteristics are still in doubt. This study programme focused on the mechanical performances of Carbon Fibre Reinforced Polymer (i.e. CFRP with vinyl ester matrix) composite plate bonded to concrete exposed to tropical climate conditions. In this programme the test samples were divided into three groups, namely; CFRP plate, epoxy adhesive and CFRP plate bonded to concrete (stressed and unstressed). The specimens were experimented to designated exposure conditions for six months, namely; laboratory (LB), outdoor (OD), plain water (PW-wet/dry cycles) and salt water (SW wet/dry cycles). After exposure, the groups of CFRP plate and epoxy adhesive were loaded in tensile and shear while the group of CFRP plate bonded to concrete was loaded to failure under tension-compression loads. The performance of the exposed specimens was then compared with that of similar control specimens in terms of strength and modulus for CFRP plate and epoxy, respectively. In addition, the load carrying capacity, bond slips, local force and bond stress distribution for CFRP plate bonded to concrete were studied. The results of the study had indicated that exposure to tropical climate had reduced the strength properties of CFRP plate by nearly 10% for those exposed to plain and salt water, while in contrast to that, those specimens exposed to outdoor showed an increment of strength of up to 5% compared to the control group. Meanwhile, the elasticity of CFRP plate was significantly affected by exposure to salt water, i.e. 15% reduction compared to the control ones. It was also found that all the exposure conditions had reduced the epoxy shear strength by nearly 32%, with the exposure to plain water being the most aggressive. On the other hand, the exposure conditions had also affected the epoxy shear modulus by up to 25%, where the most reduction was shown by specimens exposed to plain water. Finally, it can be said that the tropical climate conditions had significantly influenced the mechanical bond performances of the bonded specimens. This could be seen for those specimens that had been exposed to outdoor condition which experienced debonding at load level about 30% of the ultimate load compared to about 50 to 60% load level for those exposed to the other three exposure conditions. It was also found, that all exposure conditions produced non-linear bond slips at specimens’ most stressed end which could be related to the influences of moisture ingression on bond interfaces that weaken the bond performances
Dynamic Time Warping fixed - frame coefficient with pitch feature for speech recognition system with neural network
(University Technology Malaysia, 2007) Sudirman, Rubita
Automatic Speech Recognition products are already available in the market since many years ago. Intensive research and development still continue for further improvement of speech technology. Among typical methods that have been applied to speech technology are Hidden Markov Model (HMM), Dynamic Time Warping (DTW), and Neural Network (NN). However previous research relied heavily on the HMM without paying much attention to Neural Network (NN). In this research, NN with back-propagation algorithm is used to perform the recognition, with inputs derived from Linear Predictive Coefficient (LPC) and pitch feature. It is known that back-propagation NN is capable of handling large learning problems and is a very promising method due to its ability to train data and classify them. NN has not been fully employed as a successful speech recognition engine since it requires a normalized input length. The nonlinear time normalization based on DTW is identified as the suitable tool to overcome time variation problem by expanding or compressing the speech to a desired number of data. The proposed DTW frame fixing (DTW-FF) algorithm is an extended DTW algorithm to reduce the number of inputs into the NN. This method had reduced the amount of computation and network complexity by reducing the number of inputs by 90%. Therefore a faster recognition is achieved. Recognition using DTW showed the same results when LPC or DTW-FF feature were used. This indicates no loss of information occurred during data manipulation. Pitch estimate is another feature introduced to the NN that has helped to increase recognition accuracy. An average of 10.32% improvement is recorded when pitch is added to DTW-FF feature as input to back-propagation NN using Malay digits samples. The back-propagation algorithm was then designed with both the Quasi Newton and Conjugate Gradient methods. This is to compare which method is able to achieve optimal global minimum. Results showed that Conjugate Gradient performed better.
Pemantapan proses menentukan pampasan mencukupi dalam pengambilan tanah di negeri Kedah Darul Aman
(Universiti Teknologi Malaysia, 2008) Ismail, Mazlan
The concept of determining the amount of adequate compensation in land acquisition has been discussed by many; yet, there is no clear measure to explain the real meaning of adequate compensation to the land owners. this is due to the fact that not much research has been conducted to explain the meaning of adequate compensation in land acquisition. therefore, the research seeks to explore the meaning of adequate compensation to the affected land owners by identifying the elements of land owners’ dissatisfactions in land acquisition in the case study areas. data were gathered from selected land owners, land administrators and valuers on ways to determine the meaning of adequate compensation. land owners were interviewed from several areas in kedah namely kerpan, beris, kg. tok murad and jalan sik-gurun whose lands were acquired for prawn rearing, dam, al-bukhary higher learning institute and road expansion projects respectively. these areas represented significant public interests on issues in land acquisition in kedah. data were analyzed using qualitative analysis to form patterns, categories and themes in order to achieve the research objectives. the findings were presented in the form of phrase expressions, charts, diagrams and tables. the research revealed that adequate compensation comprises all losses without taking into consideration any special or sentimental values of the land taken. the valuation must be done in accordance with the date of acquisition and, no differentiation in values should be made with reference to the proposed use of the land after acquisition. moreover, the acquiring authority has to consider any losses of fruit bearing trees and pays extra compensation for the hardships faced by the land owners as a result of the land acquisthe concept of determining the amount of adequate compensation in land acquisition has been discussed by many; yet, there is no clear measure to explain the real meaning of adequate compensation to the land owners. this is due to the fact that not much research has been conducted to explain the meaning of adequate compensation in land acquisition. therefore, the research seeks to explore the meaning of adequate compensation to the affected land owners by identifying the elements of land owners’ dissatisfactions in land acquisition in the case study areas. data were gathered from selected land owners, land administrators and valuers on ways to determine the meaning of adequate compensation. land owners were interviewed from several areas in kedah namely kerpan, beris, kg. tok murad and jalan sik-gurun whose lands were acquired for prawn rearing, dam, al-bukhary higher learning institute and road expansion projects respectively. these areas represented significant public interests on issues in land acquisition in kedah. data were analyzed using qualitative analysis to form patterns, categories and themes in order to achieve the research objectives. the findings were presented in the form of phrase expressions, charts, diagrams and tables. the research revealed that adequate compensation comprises all losses without taking into consideration any special or sentimental values of the land taken. the valuation must be done in accordance with the date of acquisition and, no differentiation in values should be made with reference to the proposed use of the land after acquisition. moreover, the acquiring authority has to consider any losses of fruit bearing trees and pays extra compensation for the hardships faced by the land owners as a result of the land acquisition. the authority is also suggested to conduct more frequent discussions with the land owners, to make the land acquisition process more transparent, to provide efficient ways of delivering notices, to hold conducive public hearing and to make prompt payments.ition. the authority is also suggested to conduct more frequent discussions with the land owners, to make the land acquisition process more transparent, to provide efficient ways of delivering notices, to hold conducive public hearing and to make prompt payments.
Development of aerobic granular sludge technology for domestic wastewater treatment in hot climates
(Universiti Teknologi Malaysia, 2008) Nor Anuar, Aznah
Conventional domestic wastewater treatment plants based on activated sludge technology require large footprint (big settling tank) due to the relatively slow settling characteristics of sludge flocs. Aerobic Granular Sludge (AGS) technology offers a possibility to design a compact system based on simultaneous organic and nutrient removal and because of the good settling characteristics of the AGS, the use of a big settling tank is not necessary. Therefore, the installation can be more compact, at a cheaper cost. The aim of this study was to develop AGS system for domestic wastewater treatment applications in hot climate conditions. Special emphasis is given to the settling characteristics and physical strength of the AGS. Therefore, a 3-litre laboratory-scale reactor known as Cyclic Aerobic Granular Sludge Bioreactor (CAgSBio) was designed and used. The operation of the reactor was based on the Sequencing Batch Reactor (SBR) system with a complete cycle operation of three (3) hours and specifically designed to be operated for twenty-four (24) hours continuously at temperature of 30°C. A 3-litre laboratory-scale reactor in Delft University of Technology (TU Delft), the Netherlands operated at 20°C was also used to compare the results on AGS granulation and performance. AGS developed at this low temperature and from a 1.4 m3-pilot plant at Ede Wastewater Treatment Plant, the Netherlands (fed with pre-treated domestic wastewater) were also used for a physical strength study, to compare with AGS at 30°C. All analytical measurements performed in this study were conducted according to Standard Methods for the Examination of Water and Wastewater (APHA, 2005). The study shows that after ninety (90) days of operation, stable AGS (fed with synthetic wastewater) with average size of 1.1 mm were formed at 30°C. To demonstrate the simultaneous organic and nutrient removal by AGS, a removal study was also conducted. CAgSBio system showed stable removal performance. Average removal efficiencies during steady state cycles at 30°C of organic carbon, total inorganic nitrogen and phosphorus reached 100%, 94% and almost 98% respectively. A study with actual wastewater (pre-treated domestic wastewater) at 30°C indicates that the granulation process does occur but at a slower rate (125 days is essential to develop mature granules) compared to synthetic influent (90 days). Meanwhile, AGS settling behaviour study shows that AGS settled relatively fast (velocities >12 mh-1 for size > 0.2 mm) compared to other conventional sludge flocs. The study also indicates that excessive mixing is not favourable for AGS reactors. Thus, the mixing criteria for AGS reactors was developed based on results obtained through experiments under mechanical and aerated-mixing conditions. Finally, a procedure was developed to evaluate the AGS strength based on the stability of AGS against shear stress. Determination of a stability coefficient (S) was introduced as an indicator of AGS strength. The results shows that AGS at 20°C and 30°C, fed with synthetic wastewater are very stable. For AGS fed with pre-treated domestic wastewater, the AGS at 30°C (produced using the laboratory-scale reactor) is more stable than the AGS at 20°C (produced using the pilot plant). As a conclusion, stable and compact AGS can be developed and performed effectively in hot climate conditions for domestic wastewater treatment applications, particularly as an alternative technology which is compact, high speed operation process (≈3 hours complete cycle) and more efficient
The effectiveness of various structural system in reducing tall building response due to wind
(Universiti Teknologi Malaysia, 2008) Abd. Samat, Roslida
Recently, many tall building structural systems have been innovated in order to reduce the building responses due to wind loading. However, there are no systematic study conducted on the effectiveness of the different tall building systems in minimizing the responses of the building due to wind load. The objective of this research is to study the effectiveness of five tall building structural systems: core wall, outrigger, belt wall, tube-in-tube and megacolumns in minimizing the building responses due to wind. Reinforced concrete buildings with 64 stories and the ratio of height to the breadth of 6:1 were analysed for their responses to wind load. The buildings that were analysed have five different structural systems. The natural frequencies and eigenvectors of the buildings in the along-wind, across-wind and torsional mode are computed by a structural engineering software. The along-wind responses are determined by employing the procedures from the ASCE 7-02 while the across-wind and torsional responses of the buildings are calculated based on the procedures and wind tunnel data available in a data base of aerodynamic load. The database is comprised of high-frequency base balance measurements on a host of isolated tall building models. It is found that increasing the size of the core wall is more effective to reduce the building responses than increasing the thickness of the core wall. As for the outriggers, the most optimum position to construct the outriggers is between one quarter to two third of the height of the building. However, outrigger system is effective to reduce only the along-wind and acrosswind responses. The torsional responses cannot be reduced by the addition of the outriggers. Interestingly, the addition of the belt walls will reduce the torsional response of the buildings which otherwise cannot be lessened by the outriggers. The belt walls also further reduce the building responses in the along-wind and acrosswind directions. Moreover, the most optimal tube-in-tube structure is achieved when the spacing of the exterior columns is 4 metre, while the addition of megacolumns to the structural systems reduces the building responses drastically in all the three directions
Influence of rainfall pattern on suction distribution and slope stability
(Universiti Teknologi Malaysia, 2008) Lee, Min Lee
Rainfall-induced slope failure is one of the most severe disasters in tropical regions causing major loss of life and property. This study was carried out to investigate the effect of various rainfall patterns on the suction distribution, hence on slope stability. A series of numerical analyses were conducted via Seep/W on an infinite slope model to simulate the responses of the slope consisting of typical soil types to the extreme rainfalls of five selected locations in the Malaysian Peninsular. One-dimensional infiltration tests were also performed by using a soil column model, instrumented with tensiometers and gypsum blocks, to provide laboratory evidences for the findings of numerical study. The study shows that the combination of antecedent rainfall and major rainfall is the critical rainfall pattern for shallow failure, while the prolonged antecedent rainfall contributes to the deep-seated failure for most types of soil. The critical combined duration of antecedent rainfall and major rainfall varies from 11 hours to 13 days. The duration can be estimated from an equation proposed in this study. The critical duration of antecedent rainfall varies from 1 day to 30 days, depending on the soil type, slip plane depth and geographical location. Soil permeability could significantly affect the pattern and the duration of critical rainfall. A computer software (PERISI) was developed to perform the preliminary evaluation of rainfall-induced slope instability. The critical suction distribution and factor of safety computed by PERISI software show good agreement with the results of numerical simulation and field monitoring
Design and operating parameters of a fluidized bed for the combustion of municipal solid waste using standpipes air distributors
(Universiti Teknologi Malaysia, 2009) Johari, Anwar
Hydrodynamic studies and combustion of simulated and actual municipal solid waste were carried out in a fluidized bed system. A wide range of parameters was investigated in hydrodynamic study after which the optimum parameters were implemented in the combustion studies. A newly fabricated standpipes air distributor (primary air inlet) was designed based on findings of the optimum orifice diameter, orifice distance and distance between pipes. Orifice diameter, orifice distance and distance between pipes of 3 mm, 10 mm and 70 mm were used in the hydrodynamic studies of circular and rectangular columns (CHS and RHS). The operating parameters investigated in the CHS and RHS included the effect of sand sizes and aspect ratios on the fluidization profile. Standpipes air distributors having the same orifice diameter and distance but with a wider pipe distance of 200 mm were used in the hydrodynamic studies of a bigger rectangular (big scale) column. Different air flow strategies were implemented to ensure good mixing between sand and samples and to investigate the penetration of the incombustibles into the sand bed. Parameters studied in the combustion of municipal solid waste included the effect of fluidizing velocity and air factor on the combustion profile in the bed as well as the freeboard region with standpipe air distributor design and dimension established from the hydrodynamic studies of a bigger scale rectangular column. Findings from the CHS and RHS showed that sand particles with mean size of 0.34 mm performed good fluidization profile compared to other coarser sand sizes. The ratio of the bed height over diameter of column (Dc) for good fluidization was determined at H = Dc for the circular column whereas the ratio of the bed height (H) over the length of column was observed at H
The characterization and removal of foam promoting impurities from blended methyldiethanolamine - piperazine solution using membrane
(Universiti Teknologi Malaysia, 2009) Ratman, Iwan
The removal of acid gases from natural gas stream is an important process in many gas processing plants and for environmental protection. The most widely used acid gas removal technology nowadays is the absorption process using amine-based solvent. Foaming is the major cause that leads operational problems, resulting in excessive solvent losses, failure to meet treated gas specification and a reduction in gas treating capacity. Therefore, the main objectives of this research were to study the foam characteristics and the surface tension phenomenon of alkanolamines solution and to reduce their foaming promoters. The effect of natural gas impurities (foam promoters) in the blended methyldiethanolamine (MDEA)-piperazine solution such as hydrocarbon liquids, iron sulfide (dissolved solid), sodium chloride (salt), acetic acid (organic acid), methanol (hydrate inhibitor) and glycol (dehydrating agent) were investigated. The concentration of MDEA was found to significantly influence the foam activity in the solution. Iron sulfide, hydrocarbon and sodium chloride present in the solution had been identified as the impurities which apparently contributed to the high foaming tendency. At 5000 ppm concentration of impurities, the foam height achieved was 425 ml. Iron sulfide appeared to be the major foam promoter in the range of concentration solutions studied. Response surface methodology and central composite design had been applied to optimize the three factors that affected the foaming phenomenon. These factors were then correlated to the surface tension and foaming tendency. Asymmetric mixed matrix membrane (MMM) was applied to remove foam promoters in the amine solvent in order to reduce its foaming tendency. The MMM characteristics and performance were tested using scanning electron microscope, differential scanning calorimetry, Fourier transform infrared and membrane filtration tests. The contents of iron sulfide, hydrocarbon and sodium chloride as the main foam promoters had been successfully reduced as indicated by reduction of surface tension values by 12 %, 6.3% and 16 % respectively. These results indicated that membrane is a promising and viable technology to enhance the effectiveness of gas treatment system through the reduction of foam formation
Konsepsi pengajaran pensyarah dan kaitannya dengan pendekatan pembelajaran pelajar
(Universiti Teknologi Malaysia, 2009-07) Sihes, Ahmad Johari
The general purpose of this descriptive research is to determine lecturers’ teaching conceptions and the factors influencing their teaching conceptions. The research also studied the relations between lecturers’ teaching conceptions and students’ approaches to learning. The teaching conceptions examined are Knowledge Transmission (KT) Orientation and Learning Facilitation (LF) Orientation. The factors being studied were lecturers’ background consisting of teaching experience, academic discipline and position while the teaching environment factor consists of class size, academic workload, support for teaching, control of teaching and students’ characteristics. Stratified random sampling was used to determine the sample and a total of 313 lecturers were involved to study the lecturers’ teaching conceptions. Data were collected from the lecturers using Lecturers’ Conceptions of Teaching and Learning (LCTL) questionnaire to determine the lecturers’ teaching conceptions meanwhile Perception of Teaching Environment (PTE) questionnaire was used to evaluate perception of their teaching environment. A total of 34 lecturers and 779 students were involved in the study to determine the relations between lecturers’ teaching conceptions and students’ approaches to learning. Data from students were collected using Revised Two-Factor Study Process Questionnaire (R-SPQ-2F). Descriptive, correlations, multiple correlations, three-way ANOVA, one-way ANOVA, one-way MANOVA and multiple regression statistics were used to analyse the data set at 0.05 significance level. Results revealed that lecturers are more inclined towards the LF Orientation (mean=4.40) compared to the KT Orientation (mean=4.21). There was no significant difference in the KT Orientation among the lecturers based on their background factor. However lecturers from different academic background have significantly different levels of LF Orientation. The lecturers’ perception of their teaching environment was at medium level (mean=3.48) and has significant relationships with both teaching conceptions orientations (KT; R=0.230, p=0.005) (LF; R=0.363, p=0.0001). Support for teaching element significantly contributed 4.2% towards the variance in the KT Orientation while position, control of teaching and support for teaching elements significantly contributed 12.8% towards the variance in the LF Orientation. Research findings also showed that there was a significant difference in change of surface learning approach among students taught by lecturers who are high in LF Orientation and low in LF Orientation. A model to enhance lecturers’ teaching conceptions that reduce students’ surface learning approach in university is proposed.
Compatibiliser effects on properties of polyamide-6/acrylonitrile-butadiene-styrene and polyamide-6/acrylonitrile-butadiene-styrene/short glass fibre thermoplastic composites
(Universiti Teknologi Malaysia, 2010) Arsad, Agus
Polyamide-6 (PA6), acrylonitrile-butadiene-styrene (ABS)and their blends are an important class of engineering thermoplastics that are widely used in electronic and automotive industries. Many efforts have been taken to improve the properties of both pure components and the blends. It was for this reason that the dynamic mechanical and rheological properties of PA6/ABS blend systems compatibilised by acrylonitrile-butadiene-styrene–maleic anhydride (ABS-g-MAH) was studied. The compatibiliser levels were kept up to 5wt. % in the blends. Short glass fibre (SGF) was used to improve the stiffness of the compatibilised blends and the fibre contents were from 10 to 30 wt. %. Therefore, the reason behind blending the PA6/ABS blends with short glass fibre was to balance the toughness and stiffness. Both the blends and corresponding composites were compounded using a counter-rotating twin screw extruder. Tensile, flexural and impact properties were determined using the injection moulded test samples according to ASTM standards. The mechanical properties of the blends and the composites were investigated in both static and dynamic modes. Rheological properties were investigated using rotational and capillary rheometer. In general, the mechanical strength either dynamic (refer to dynamic mechanical properties) or static conditions improved by incorporation of compatibiliser to the PA6/ABS blends. The incorporation of SGF into the PA6/ABS blends enhanced the mechanical strength but reduced the toughness of the composites. The rheological measurements confirmed the interaction between the blend components with the incorporation of compatibiliser has been improved. However, the compatibiliser has no favourable effect on the mechanical properties of the composites although it has significant effect on the blends of PA6/ABS. The compatibiliser increased the melt viscosity of the blends. The SGF increased the rheological properties especially viscosity and flowability of the composites. The optimum ratio of compatibiliser and SGF concentration were determined using power law, n and consistency index, K analyses. From the analysis, the optimum ratio obtained was 1.5 wt. % for 50/50 and 60/40 PA6/ABS blends and 3 wt. % for 70/30 PA6/ABS blends. The n values drastically decreased, when concentration of the SGF was about 20 wt % indicating more pseudoplastic nature for the composites and suggesting that, 20 wt % is the optimum SGF concentration.
Development of hollow fiber membranes for carbon dioxide absorption in gas-liquid membrane contactors
(Universiti Teknologi Malaysia, 2010) Mansourizadeh, Amir
Porous asymmetric polyvinylidene fluoride (PVDF) and polysulfone (PSF) hollow fiber membranes were structurally developed to improve gas permeability, wetting resistance and carbon dioxide (CO2) absorption flux. The membranes were prepared via a wet phase-inversion process and used in gas-liquid membrane contactors for CO2 absorption. Phase-inversion behavior of the polymer solutions was studied by plotting the ternary phase diagrams of polymer/solventadditive/water. The effect of different non-solvent additives on the structure and performance of the PVDF and PSF membranes was investigated. The membranes structure was examined in terms of gas permeation, critical water entry pressure (CEPw), collapsing pressure, overall porosity, contact angle, mass transfer resistance and field emission scanning electronic microscopy (FESEM). The CO2 absorption performance of the membranes was investigated and compared with the commercial polypropylene (PP) and polytetrafluoroethylene (PTFE) hollow fiber membranes. In addition, the effect of different operating conditions on the physical and chemical CO2 flux of the PVDF membrane was also investigated. The results showed that the PSF membranes have a thicker skin layer with smaller pore sizes and lower surface porosity compared to the PVDF membranes. The PVDF membranes demonstrated low mass transfer resistance and high wetting resistance. Therefore, the hydrophobic PVDF membranes indicated an improved structure, which considerably increased the CO2 flux compared to the PSF membranes and symmetric PP and PTFE commercial membranes. A maximum CO2 flux of 8.20×10-4 mol./m2 .s was achieved at the absorbent flow rate of 310 ml/min, which was approximately 110 % higher than CO2 flux of the PTFE membrane at the same operating conditions. In case of physical absorption with distilled water, a significant increase in the CO2 flux was observed as the pressure increased and the temperature decreased. However, in the case of chemical absorption with 1M sodium hydroxide (NaOH) solution, the CO2 flux was significantly increased by increasing temperature, where the reaction rate was dominant. Moreover, it was found that the operation remains stable at the same gas and liquid pressure without bubble formation in the liquid phase when the liquid contacts the skin layer of the membrane. Results of the long-term study demonstrated that after a certain initial CO2 flux reduction the membrane performance maintained constant over 150 h operation. Therefore, it can be concluded that the porous hydrophobic membrane with developed structure can be a promising alternative for CO2 removal from the gas streams.
The performance of membrane bioreactor in treating high temperature municipal wastewater
(Universiti Teknologi Malaysia, 2010) Al Amri, Abdullah Ali
Membrane bioreactor (MBR) is a promising technology which has been applied to treat a wide range of municipal wastewater in different regions around the world. However, it has not yet been employed in arid and semi arid areas such as Arabic Gulf Cooperation Council States (AGCCS). The application of MBR process in treating high temperature municipal wastewater (HTMW) has not been documented and could pose as an obstacle. Therefore, the aim of this study was to investigate the effect of high temperature on MBR process in treating municipal wastewater. The objectives were to study the biomass properties, the membrane fouling tendency and the biological and final removal efficiencies (Bio and Fin R E) of COD, NH3-N and turbidity. In this study, a 3.6 L lab-scale aerobic MBR was seeded with 1.5 L activated sludge inoculum from Oman and was fed with a real municipal wastewater from Taman Pulai Utama sewage treatment plant in Johor. The system was then run under four main experimental stages. For the first three stages, it was run at three various temperatures (25, 35 and 45°C) and two different fluxes (10 and 15 LMH). In the fourth stage, it was run at drastic temperature changes with constant flux (10 LMH). The study demonstrated that the increase in temperature caused biomass shock. This resulted in the biomass reduction, lowered sludge settling properties and higher supernatant’s turbidity. Due to biomass reduction (low richness and diversity), DO and ML pH increased. The temperature increase led to increase in SMP carbohydrate and protein, and decrease in EPS protein. Biomass reduction, high pH, SMP concentration increase and EPS decrease were the factors that caused relatively high membrane fouling. TMP and BWP ascended critically with temperature and flux increase. The highest TMP values scored were 348 mbar at 10 LMH flux and 429 mbar at 15 LMH flux, and both of them were at 45°C. Membrane openings widen with temperature increase, thus membrane fouling tended to be internal rather than external at higher temperatures. As a result of biomass shock the removal efficiencies dropped temporarily and then improved gradually with the acclimatization despite the flux increase. COD Bio R E was 90%, 84% and 62%, while Fin R E was 95%, 91% and 79% at 25°C, 35°C and 45°C respectively. Both NH3-N removal efficiencies were very high up to 100% at 25 and 35°C, while at 45°C they were 52% Bio R E and 56% Fin R E as high nitrification has not yet been achieved at high temperatures. Despite the higher biomass shock at drastic temperature changes stage, COD and turbidity Fin R E were very high up to 90% and 100% respectively, while NH3-N Fin R E was nearly 50%. The viscosity decreased with the increased in temperature and SVI. In spite of the critical operating conditions, the use of hollow fiber membrane module was able to achieve comparatively good removal efficiencies, however at the highest temperature i,e (45°C) the membrane fouling was the highes
Parameter optimization methods for calibrating tank model and neural network for rainfall-runoff modelling
(Universiti Teknologi Malaysia, 2010) Kuok, King Kuok
The transformation of rainfall into runoff involves many highly complex hydrological components that require various hydrological data and topographical information. These data are hard to obtain and not consistent. Therefore, hydrologic tank and artificial neural networks models that require only rainfall and runoff data were proposed. The selected study area is Bedup Basin, Sarawak, Malaysia, a rural catchment in humid region. A new global optimization method named as particle swarm optimization (PSO) was proposed, and compared with shuffle complex evolution and genetic algorithm techniques for calibrating the tank models’ parameters automatically. PSO is also hybrid with neural network to form particle swarm optimization feedforward neural network (PSONN) to overcome the slow convergence rate and trapping at local minima problems. PSONN performance is then compared with multilayer perceptron and recurrent networks, that used backpropagation algorithm. Models performances are measured using coefficient of correlation (R) and Nash-Sutcliffe coefficient (E2). Generally, artificial neural networks performance is slightly better than tank model. Results of tank model calibration indicate that PSO method appeared to be the best based on its robustness, reliability, efficiency, accuracy and smallest variability in boxplots. Shuffle complex evolution follows as the second best and the third best is genetic algorithm for both daily and hourly runoff simulation. Among multilayer perceptron, recurrent and PSONN investigated, recurrent network forecasts daily and hourly runoff most accurately, followed second best by multilayer perceptron and lastly PSONN. PSONN has proven its remarkable capability to simulate daily and hourly runoff with an acceptable accuracy. This study revealed that artificial intelligence methods especially PSO, have offered a real prospect for an efficient, simple, cheaper, more flexible, and well suited to model flood processes
Secondary school teachers psychological status and competencies in e-teaching during Covid-19
(Mendeley Data, 2010-10-10) Wong,Kai Yan; Sulaiman, Tajularipin; Ibrahim, Amalina; Kunchi Mohd, Abdul Gaffar; Omrah Hassan @Hussin
RESEARCH OBJECTIVE 1. To determine teachers’ psychological status (stress, anxiety, depression) during the Covid-19 outbreak. 2. To determine teachers’ competencies in e-teaching (application, monitoring, evaluation). 3. To determine examine teachers’ working motivation. 4. To determine the relationship between secondary school teachers’ psychological status and competencies in e-teaching during Covid-19. Overall, the study shows that e-teaching during Covid-19 pandemic is promising though every teacher is caught by surprise and overwhelmed. Though they face stress, anxiety and depression but it is at moderate level, and they are not deterred from fulfilling their responsibility. Despite of that e-teaching is conducted effectively by teachers at moderate level on the higher end due to team spirit and cooperation among teachers. It is also driven by strong motivation among teachers to carry out their responsibilities. Last but not least, a negative correlation was determined between Malaysia secondary school teachers’ psychological status and competencies in e-teaching during Covid-19.
Evaluation of sustainable construction understanding among AEC professionals
(Mendeley Data, 2010-12-22) Muhammad-Jamil Abubakar
The questionnaire and responses of the evaluation of sustainable construction understanding among AEC professionals in Nigeria's AEC industry
Employment core abilities skills among trainees with physical disabilities in special vocational institutions.
(Universiti Teknologi Malaysia, 2011) Abdul Latib, Azlan
This research was conducted to identify the level of Employment Core Abilities Skills (ECAS) and the factors that affect the ECAS of Trainees with Physical Disabilities (TPD) in special vocational training institutions and sheltered workshops in Malaysia. The quantitative survey method, along with the elements of qualitative study approaches, were used concurrently. ECAS was measured using a researcher-made questionnaire adapted from the Moraine Park Technical College’s Core Abilities (MPTC, 2005) containing 37 items in the dimensions of work, communication, learning, cooperation, responsibility, self value and thinking skill. The purposive sampling technique was used in selecting the respondents, and 155 trainees participated in this survey. The quantitative data were analyzed using descriptive statistics. T-test and one-way analysis of variance (ANOVA) were used to measure the differences among variables. The measurement model analysis using AMOS 16 was then used to identify the core skills that are important to ECAS. Interviews were conducted to identify the factors that affect the ECAS from 42 respondents comprising the trainees, trainers and management officers of the institutions. Content analysis was used to analyze the narrative texts which represented a verbatim record of the interviews. The study found that the ECAS level among trainees with physical disabilities is at high level, and there are no significant differences in ECAS based on the demographic variables. However, the “work cooperatively” component was found not to be so important to ECAS compared to other skill components. The study shows that the institutional, trainer and peer factors play important role in enhancing the trainee’s ECAS. The trainee’s past experience was found to influence the ECAS. This research proposes several models showing the ECAS and their influencing factors that can be used as a guideline for further study, employment, assessment, teaching and learning of ECAS for TPD in special vocational institutions.
Properties of starch-based packaging film incorporated with chitosan and lauric acid as antimicrobial agents
(Universiti Teknologi Malaysia, 2011) Salleh, Eraricar
This study aimed to develop the antimicrobial (AM) packaging based on wheat starch incorporated with chitosan and lauric acid as antimicrobial agents. A series of blends with different ratio of starch, chitosan and lauric acid (S:C:LA) were prepared by casting method. Effects of incorporation of antimicrobial agents into starch-based film were investigated in order to improve the spectrum activity based on measured distributions of inhibitory results. The diffusivity equation approach for describing the antimicrobial effects was also extended to include information on the molecular size of particles in the formed matrices. The Agar Disc Diffusion Assay and Liquid Culture Test measured the distributions of inhibitory effect towards the type of bacterial contamination in terms of Gram-positive, Gram-negative and their combination of wider spectrum activity in the blend films. For the first time, the inhibition size distribution resulting from rationing of base polymers and lauric acid as filler in the starch-base film itself was quantified. Spectrum activity of different Gram-stained bacteria as measured by the bacterial growth inhibition, gave surprisingly consistent pattern on rationing of compositions in the film. This indicates that the spectrum activity produced by the antimicrobial components can be related directly to the ratio on blending during film preparation. This phenomenon is proven by dominating of chitosan (S:C:LA ratio 1:9:0.08 to 3:7:0.24) for 48% increase of effective E. coli inhibition (Gram-negative bacteria). More positively, however, it signifies that the affinity of lauric acid towards starch as reported by previous research indicates relatively unambiguously the ratio required to achieve a constant degree of B. subtilis (Gram-positive) bacterial inhibition from starch/chitosan/lauric acid dominating of S:C:LA ratio at 4:6:0.32 to 7:3:0.56. Furthermore, S:C:LA ratio 8:2:0.64 and 9:1:0.72 showed good synergic inhibition of 54% higher relative to sole chitosan towards both bacteria. This implies that the ratio index is inherently meaningful, and explains why it has been possible in this work to relate the ratio index directly to a change in physical property of the structural-modified polymer matrices. Further studies of antimicrobial effects investigated the mode of release from the base film. The release of lauric acid in fatty acid food stimulant was satisfactorily expressed by Fickian-diffusion mechanism described by zero order kinetics which indicated that lauric acid released from the film matrix remains constant over time. The physical and mechanical properties of the films were improved relative to sole starch film. Increasing starch amount resulted in progressive interaction and stronger bonding between starch and chitosan molecules nevertheless decreasing the mechanical properties as shown by the results from OTR, WVTR and microstructure studies. S:C:LA ratio 5:5:0.40 gave the most smooth surfaces followed by S:C:LA ratio 6:4:0.48 which confirmed the most homogeneous and dense structure achievable. That is an indicative of a homogeneous and good miscibility or blending of starch and chitosan where SEM, XRD and FTIR analysis confirmed these properties. Results showed that S:C:LA ratio 5:5:0.40 is the phase inversion between S:C:LA ratio dominate by chitosan (S:C:LA ratio 1:9:0.08-4:6:0.32) and S:C:LA ratio dominated by starch (S:C:LA ratio 6:4:0.48-9:1:0.72). These were proven by the SEM, XRD, tensile strength, percent elongation, water uptake, diffusion coefficient, OTR and WVTR results analysis.
Fouling studies on natural rubber skim latex concentration using integrated ultrafiltration membrane system
(Universiti Teknologi Malaysia, 2011) Veerasamy, Devaraj
Fouling studies on natural rubber skim latex (NRSL) concentration using an integrated ultrafiltration membrane system has been conducted. This study focuses on parameters which influence fouling, identification of foulants, optimization of latex preservation system and subsequently identification of fouling mechanisms in NRSL concentration process. This investigation is divided into three stages. In the first stage, parameters affecting membrane fouling were studied by adopting an ideal preservation system for concentrating NRSL effectively. The second stage involves studying and identifying the major foulants in the ultrafiltration membrane system during the concentration of NRSL. The optimization of latex preservation system was conducted based on results from previous stages. Fouling mechanisms were identified to quantify all the hydraulic membrane resistances and subsequently the most significant resistances as well as the chemical nature of foulants were determined. The final stage of the study is to minimize the most significant resistance by in-situ ultrasonication in order to optimize the NRSL concentration process. The membrane resistances were quantified through membrane autopsy procedures and by using the resistance-in-series model. The pure water flux test was used to facilitate the design of an effective membrane cleaning procedure. Attenuated total internal reflection fourier transform spectrophotometer (FTIR-ATR), scanning electron microscope (SEM), atomic force microscope (AFM), energy-dispersive X-ray spectroscopy (EDX), atomic absorption spectrophotometer (AAS) and total organic carbon analyzer (TOC) were used in membrane autopsy procedures to characterize the foulants. Results show that the composite preservation system consisting of 0.3% ammonia and 0.2% ammonium laurate is the optimum preservation chemical composition for the concentration of NRSL. The concentration polarization resistance was found to be the highest of the membrane resistances during skim latex concentration process. The foulants identified are amino acids, rubber particles and protein derivatives. Alkaline (0.1M NaOH) and acid (0.1M HNO3) cleaning of the fouled polyvinylidene fluoride (PVDF) tubular membrane at a temperature of 50°C with ultrasonication, achieved the highest flux recovery of 93%. Concentration polarization membrane resistance was found to be the biggest threat to an efficient NRSL concentration process as it can develop at any time, at any trans-membrane pressure, and at any feed concentration. In-situ ultrasonication of 45 kHz frequency was applied to reduce the concentration polarization resistance during NRSL concentration process. The application of in-situ ultrasonication effectively reduced the time required to achieve the targeted concentration and cost savings by almost 30%. The integrated ultrafiltration membrane system developed in this study could effectively optimize the NRSL concentration. This newly developed system would become an economically and environmentally viable process to solve environmental problems associated with the natural rubber (NR) latex industry.

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