University of Technology Malaysia
Universiti Teknologi Malaysia Institutional RepositoryNot a member yet
70456 research outputs found
Sort by
Change management and data governance
No full textChange management is an essential and integral part of an organization in this data-driven era. This article analyzes literature reviews on change management methodologies in several domains. It is also pointed out the application of change management and data governance under big data has great theoretical and practical significance. As an industry with relatively deep application in financial technology, banking has accumulated data for a long time and large volume. A large number of external information is introduced in business management. This includes research on promising practices process and appropriate tools in change management to build a closed-loop control system of banking operations
Performance of bitumen improved with coconut shell activated carbon additives
Full text linkThe agricultural industry alone generates a wide range of waste materials, such as shells, palm oil, husks, leaves, and fronds. Because of the growing waste generation, researchers have investigated alternative methods to recycle waste materials for bitumen modification to improve road materials and reduce solid waste pollution. While the utilisation of agricultural wastes for activated carbon production has been reported, there is limited study on the potential use of activated carbon from Coconut Shells (CS) in bitumen mixtures for road construction purposes. Therefore, this study investigates the feasibility of Coconut Shell Carbon (CSC) and Coconut Shell Activated Carbon (CSAC) as additives for road construction. The CSC and CSAC were used to modify 80/100 penetration grade bitumen (80/100PEN) under three work phases. In phase one, the CS waste was converted into CSC and CSAC, followed by the production and characterisation of the additives using the Laser Particle Size Analyser (LPSA) and Elemental Analyser (EA) for proximate and ultimate analysis respectively. CSC and CSAC were then mixed in 80/100PEN bitumen at 5% to 25% to produce the modified binder. The physical, chemical, and rheological properties of the modified binder containing CSC and CSAC were evaluated in the second phase under various ageing conditions (unaged, short- and long-term aged). The laboratory tests include Fourier Transform Infrared (FTIR), softening point, penetration, storage stability, viscosity, and Dynamic Shear Rheometer (DSR). The best modified binder was determined and used to develop the modified Hot Mixture Asphalt (HMA). For the third phase, the study focused on evaluating the mechanical properties of the modified HMA in terms of Marshall stability, resilient modulus, dynamic creep, indirect tensile strength, and rutting potential. The performance of the modified HMA was compared to the control of 80/100PEN HMA and 60/70PEN HMA. According to the results, both CSC and CSAC are harder, more corrosion-resistant and lower in emissions than that of the controlled mixtures. Furthermore, the chemical activation process of CS produces CSAC with a smaller microporous pore structure than CSC. When applied as additives to the bitumen mixture, the physical and rheological properties of the modified binder have been significantly improved, including stiffness and rutting resistance. The addition of 10% CSC and 15% CSAC per weight of 80/100PEN bitumen was the best proportion for the formulation of the modified binding with optimal properties. Compared to the controlled mixtures, the 5.2% CSAC improved by 81%, 46% and 13% in rutting, fatigue, and permanent deformation resistance, respectively. It can be concluded that CSAC can be used as an additive to change the properties of bitumen, improve performance, and promote the element of sustainability in road pavement
Sustainable closed-loop supply chain model with stochastic demand and return
Full text linkThe closed-loop supply chain (CLSC) represents the supply chain that contains recovery plans for used products to be reused later in the industry. The research gap in the previous CLSC literature regarding the sustainability aspects for the CLSC was the lack of consideration for the social aspect due to its complexity. Also, the effect of demand and product returns uncertainties on the sustainability aspects of CLSC have not been considered in the previous CLSC studies under centralized management and synchronized ordering policy (SOP). Moreover, the analysis of stochastic sustainable CLSC has not been investigated in industries such as home appliances. Finally, the CLSC sustainability has not been analyzed with previous consideration of CLSC tiers coordination. Thus, the objective of this research was to model a stochastic sustainable CLSC that included the environmental, economic, and social aspects while considering uncertainties in demand and returns quantities for home appliance products under SOP and centralized management. For the proper stochastic CLSC design and mathematical modeling of the sustainable stochastic CLSC, the mathematical model was developed as a multiproduct, multi-echelon single period CLSC model under the SOP and centralized management. The stochastic sustainable CLSC model added constraints related to inventory management for the SOP, production capacity, transportation capacity, and carbon emission. The sustainable stochastic CLSC model was described as a mixed-integer non-linear programming model. The sustainability objectives were optimized using the Pareto-based constrained optimization of nonlinear approximation algorithm (Pareto-based COBYLA) by identifying the optimal quantities of parts and products for each CLSC tier and solving the optimization problem using the PYTHON program which was then compared with the nondominated sorting genetic algorithm (NSGA). The optimization results showed the significance of the stochastic demand and product return parameters on the sustainability objectives in the stochastic sustainable home appliance CLSC following SOP. The current research has contributed to the CLSC studies by developing a stochastic sustainable CLSC mathematical model following the SOP assumption for home appliance products considering the economic, environmental, and social objectives and adding the Pareto-based COBYLA solution algorithm that provided a better optimal solution for stochastic sustainable CLSC optimization in comparison with the NSGA
Effect of hull separation ratio and various ship draft to a low-speed catamaran in shallow water
Full text linkPutrajaya is Malaysia's federal administrative capital and a well-planned city. With a display of colored boats floating across the lake at Marina Putrajaya, Putrajaya Lake is turned into a beautiful sight for everyone to enjoy it. It has a high potential to be a part of the growth and development of Malaysia‘s tourism industry. In addition, the Management of Putrajaya Lake plans to cater to recreation, fishing, water sports and water transport. Currently, there are a few catamaran cruise boats that are used for sightseeing propose. Therefore, the number of cruise boats is planned to increase in the future due to accommodating a large number of tourists. The existing design of catamarans shall be improved and fulfill the limitations of Putrajaya Lake especially the low operational speed catamarans and shallow water conditions. However, limited researches has been found for low-speed catamaran studies in shallow water conditions. In order to fulfil the research gap, the current study is focused on studying the effect of hull separation ratio, H/L of the catamaran and various ship drafts, T on the low-speed catamaran in shallow water and improving the catamaran design with better operational performance in terms of better resistance and lower operating cost. This research aims to provide a more competitive hull separation ratio, H/L for catamaran boats to operate in this low-speed condition. Then, a parametric study was conducted to identify the effect of hull separation ratio and different catamaran drafts on the low operational speed in shallow water using Computational Fluid Dynamics (CFD) software, which is Flow3D. Grid independence study and method validation were carried out in methodology. Three types of catamaran drafts were calculated with water depth to ship draft ratio, h/T for 2.5, 2.32, and 2.18 to analyse the total coefficient and free surface elevation effect. The objectives of this research were successfully achieved and the collected data is able to contribute to future development either for Putrajaya Lake Management or low-speed operation catamaran. The results showed that the smaller hull separation ratio, H/L is more suitable since lower total coefficient of resistance and free surface elevation occurred during the Froude number, Fr = 0.4 condition. Also, it recommended to use of a higher water depth to ship draft ratio, h/T due to the smaller ship draft, T showed smaller total coefficient of resistance and free surface elevation. In conclusion, this research is able to contribute valuable data for Putrajaya Lake management in improving its catamaran design in the future, as public transport operators always face challenges in producing a more environmentally friendly catamaran with commercial speed
Transient removal of contaminant from a channel with differentially heated wall of cavity
Full text linkCleaning accumulated deposits inside pipe cavity are by disassembling and cleaning it part by part. Hydrodynamic cleaning of the cavity is an alternative method to clean accumulated deposits or contaminants inside the pipe cavity instead of dissembling them part by part is a tedious process or using a solvent which is not suitable in the food processing industry. This study aims to investigate the contaminants removal process from a cavity by resorting to natural flow to clean the deposits in different cavity sizes and includes different heating locations with different flow configurations. An experimental method is used to visualize the flow behaviour inside the cavity of a channel at a large aspect ratio in isothermal conditions. These results are used to validate numerical results obtained in isothermal flow conditions. For numerical study, Constrained Interpolated Profile (CIP) method is used for the advection phase of momentum and energy equation, and central difference is used to solve the non-advection phase of momentum and energy equations. The numerical studies include different aspect ratios (AR), 1 to 4, various Reynolds numbers (Re), 50 to 1000, and different locations of the heated wall inside the cavity (left wall, bottom wall, & right wall) for three different Grashof numbers (Gr), 1000, 10 000, and 100 000. The particles removal percentage at the transient and steady states are then compared and discussed. A larger aspect ratio and a more significant Reynolds number for isothermal conditions will give a higher percentage of contaminants removal except for AR = 4 and Re = 50. This particular flow shows a higher percentage of contaminant removal than AR = 4; Re = 100, 200, and 400. For mixed convection flow, one typical result can be concluded: at small Gr, the contaminant removal percentage is not changing significantly for all different heated wall positions. It is also shown that a more significant aspect ratio will produce a better contaminant removal process, and a higher Grashof number will improve the contaminant removal process. It is also found that when Gr equals 1000 and 10000, there is no significant change in the contaminant removal process and constant heat flux from the bottom wall for Gr = 100,000 gives the highest contaminant removal percentage for every aspect ratio. The highest percentage removal of contaminant is 98.94% for Gr =100 000, AR=4
Bonded sequential and parallel insertion-deletion systems in formal language theory
Full text linkInsertion and deletion are set operations that act upon structures in a predetermined fashion to create language generating devices in formal language theory, a field that involves the mathematical aspects of logic and set theory. Earlier, insertion and deletion systems that simulate the process of chemical bonding between atoms had been introduced, called bonded insertion and deletion systems. Still, these bonded systems could not generate up to recursively enumerable languages, nor could they generate abstract families of languages. Thus, the aim of this research is to introduce bonded insertion-deletion systems by combining the two aforementioned systems. Additionally, the generative power and closure properties of the sequential and parallel variants of bonded insertion-deletion systems are determined by simulating computationally complete grammars and by direct proofs, respectively. From there, graphs are constructed to visualize the mechanism of the new bonded systems by using concepts in graph theory. Furthermore, a new cryptosystem that involves both encoding and encryption is constructed using bonded sequential and parallel insertiondeletion systems based on an American Standard Code for Information Interchange (ASCII) table framework involving a bonding alphabet. From this research, it has been shown that the generative power of the new systems is up to the family of recursively enumerable languages, hence capable of generating abstract families of languages. The graphs of bonded systems and language generating graphs have been constructed such that the language of the graphs is equivalent to the language of the systems. On the other hand, the newly constructed cryptosystem using bonded insertion-deletion systems is able to confidentially store or transfer information. The findings in this research are important to advance studies in the field of DNA computing by effectively increasing the generative power of previous bonded systems, visualizing the mechanism of derivations of bonded systems, as well as providing an alternative method for information security with a nexus of bio-inspired cryptosystems
Metal oxides incorporated bauxite hollow fibre photocatalytic membrane for bisphenol a removal from aqueous solution
Full text linkThe demand for advanced water treatment technologies is increasing for the treatment of high-strength wastewater, including complex water pollutants. Removal of bisphenol A (BPA) from water has presented a major challenge for the water industry. Membrane separation has the advantages of simplicity, high speed, and high efficiency, and has received extensive attention around the world. It is well known that membrane materials and membrane processes are two of the key factors affecting the separation process. The selection of suitable membrane materials is of great significance to produce effective dual-function ceramic membrane which possesses filtration and photocatalysis features in a single unit of membrane. In this study, naturally existing bauxite was selected as a ceramic material because of its availability and the presence of iron (III) oxide (Fe2O3) and titanium dioxide (TiO2) which have potential to be used as photocatalyst. In the first stage of this work, bauxite powder was subjected to thermal treatment at different temperatures. In the second stage of the study, a hydrophilic, asymmetric bauxite hollow fiber membrane (BHFM) was fabricated by phase inversion and sintering method. To study the morphologies of BHFM, the bauxite loading and sintering temperature was varied from 45 to 55 wt% and at temperature ranging from 1250 to 1450 ºC. Then, in the third stage, the yielded membrane was subjected to the surface modification to lift up the photocatalytic properties using titanium dioxide (1wt% of TiO2) and copper oxide (1wt% of CuO) particles via hydrothermal method for the removal of BPA. TiO2 and CuO particles were modified on the surface of 50 wt% BHFM by varying the hydrothermal time of 2.5h, 5.0h and 7.5h. In the fourth stage of the study, the photocatalytic membrane was further evaluated for the photocatalytic efficiency in degradation of BPA, which was present in water. The finding of this study showed that the powder treated at 800 ºC possessed good photocatalytic degradation as it was able to degrade up to 75% of 5 mg/L BPA. 50 wt% BHFM which spun at bore fluid flow rate of 10 mL/min, air gap of 5 cm, and sintering temperature of 1300 °C induced good mechanical strength of 98.2 MPa, stable permeate water flux (PWF) of ~281.4 L/m2h and moderate BPA degradation rate of less than 70%. The pristine BHFM and modified TiO2 and CuO BHFM with hydrothermal time of 5.0h showed promising finding with almost even distribution of modified particles on the membrane surface. The experimental results of photocatalytic activity test showed that the BPA degradation of 96.8% was achieved by CuO BHFM under visible light irradiation, while for UV light irradiation, TiO2 BHFM possessed the degradation rate of 90.3% for 360 minutes. Three intermediate products were determined which were 4-(2-hydroxy-2-propanol)phenol, 4-isopropenylphenol and dihydroxybenzene. All the findings in this study are helpful for understanding the process of photodegradation and to become a promising potential treatment to degrade BPA to provide water safety for living organisms
Molecular similarity searching based on deep learning for feature reduction
Full text linkThe concept of molecular similarity has been widely used in rational drug design, where structurally similar molecules are explored in molecular databases for retrieving functionally similar molecules. The most used conventional similarity methods are two-dimensional (2D) fingerprints to evaluate the similarity of molecules towards a target query. However, these descriptors include redundant and irrelevant features that might impact the effectiveness of similarity searching methods. Moreover, the majority of existing similarity searching methods often disregard the importance of some features over others and assume all features are equally important. Thus, this study proposed three approaches for identifying the important features of molecules in chemical datasets. The first approach was based on the representation of the molecular features using Autoencoder (AE), which removes irrelevant and redundant features. The second approach was the feature selection model based on Deep Belief Networks (DBN), which are used to select only the important features. In this approach, the DBN is used to find subset of features that represent the important ones. The third approach was conducted to include descriptors that complement to each other. Different important features from many descriptors were filtered through DBN and combined to form a new descriptor used for molecular similarity searching. The proposed approaches were experimented on the MDL Data Drug Report standard dataset (MDDR). Based on the test results, the three proposed approaches overcame some of the existing benchmark similarity methods, such as Bayesian Inference Networks (BIN), Tanimoto Similarity Method (TAN), Adapted Similarity Measure of Text Processing (ASMTP) and Quantum-Based Similarity Method (SQB). The results showed that the performance of the three proposed approaches proved to be better in term of average recall values, especially with the use of structurally heterogeneous datasets that could produce results than other methods used previously to improve molecular similarity searching
Engineering and acoustical properties of gypsum composite materials containing pineapple leaf fibres
Full text linkGypsum is one of the most widely used interior building materials, notably as a finishing material. However, because to its brittle nature, as well as low compressive and flexural strength, there has been a reduction in interest in the prospective use of gypsum as an interior finish in buildings in recent years. In order to meet other mechanical and technical characteristics that are acceptable for use as interior building materials, gypsum must have high ductility characteristics and good sound energy absorption capabilities. Therefore, it is important to reduce these engineering issues using environmentally friendly and economic solutions through the use of natural fibres in the gypsum composite mixture. This study aims to characterize the engineering and acoustic properties of gypsum composites containing pineapple leaf fibres (PALF) with 5 mm and 15 mm in sizes. In determining the physical chemical and mechanical properties of gypsum-PALF composites, five different configurations containing PALF of 2%, 3%, 5%, 10%, and 20% based on the weight of the gypsum composition were prepared for both sizes of PALF. The composite specimens were tested under normal conditions after 7 and 28 days of curing. The microstructural characteristics of the composites were further examined using a Scanning Electron Microscope and an Energy Dispersive X-ray Spectroscopy (SEM/EDX), X-Ray Diffraction (XRD), and X-ray Fluorescence (XRF). The test results show that the materials reinforced with 2% PALF of 15mm in size provides composite materials with better mechanical properties of 3.70 MPa and 2.60 MPa, respectively for compressive and flexural strength. However, the compressive strength values are seen to decrease when more PALF content is mixed. The compressive strength increased up to 12.4% when 2% PALF was used in the gypsum composite. The flexural strength has increased up to 59% compared to ordinary gypsum when 2% PALF is added to the gypsum mixture. In comparison to materials reinforced with 5 mm fibre size, test results demonstrate that materials containing 15 mm PALF size provides a PALF-gypsum material with significantly better mechanical properties in terms of flexural strength. The optimum composition of the composite material was found to exist for a PALF content of 2% in the weight of the fibre size of 15 mm. Next, the study focused only on the optimal mix with 2% PALF of 15mm size tested for its sound absorption and sound loss capabilities. The series of specimens from the optimal mix are made based on market thicknesses of 9 mm, 12 mm, and 15 mm. The sound absorption and loss properties of the specimens were measured using an impedance tube instrument based on ASTM C384-04 in the frequency range between 60 Hz to 1600 Hz. As a result, it was found that there is an increase in sound absorption especially in the frequency range of 1000 Hz with a maximum value equal to 0.24. The average value of the sound absorption coefficient at 250 Hz, 500Hz, 1000 Hz and 1600 Hz or the noise reduction coefficient (NRC) shows an increase of 50% in the composite sample when compared to the gypsum sample without PALF. i.e., with a maximum value of 0.18. Sound transmission loss (SLT) also increases by 26% at a frequency of 1000 Hz. In general, adding 2% PALF to the gypsum results in greater level of STL. Based on the result of acoustical and mechanical test, it is concluded that the novel composite developed has the potential to be used to reduce agricultural waste, i.e., pineapple leaf waste. and energy savings from the use of non-natural fibres. Finally, design guidelines for gypsum-PALF composite materials in the future have also been proposed
Enhancing the immobilization of cyclodextrin glucanotransferase producing escherichia coli for direct conversion of starch to ß-cyclodextrin
Full text linkEnzyme can be considered as one of the most used and effective biocatalyst both in research and industry. However, some of the major drawbacks of using enzyme are their cost and the unavoidable one-time-usage. This problem has been temporary solved by enzyme immobilization. Nevertheless, there are still disadvantages especially in terms of the enzyme stability and reduction of catalytic activity. Therefore, whole-cell immobilization, also known as whole-cell biocatalyst, can provide a better solution as the immobilized whole-cell can provide fresh enzyme for each reaction and has high reusability. In this study, Escherichia coli (E. coli) harbouring the enzyme cyclodextrin glucanotransferase (CGTase) was immobilized to a commercial activated charcoal (ACh) for the direct conversion of starch to ß-cyclodextrin (ß-CD). The immobilization of the E. coli was enhanced by employing two methods; first, treatment to the ACh, and second, manipulating the appendages of the E. coli called curli. This is done because cell immobilization can become problematic in terms of the amount of cell successfully immobilized. The treatment of the ACh was done through chemical treatment, using four different chemicals, sodium hydroxide (NaOH), hydrochloric acid (HCl), ammonium hydroxide (NH4OH), and acetic acid (CH3COOH). The treatment was done relatively at mild conditions. Treatment with NaOH showed the highest increment in cell immobilized with more than 120 % increase. This is mainly attributed by the higher surface area and pore volume resulted from the NaOH treatment. The manipulation of the curli was done by the addition of nickel (II) chloride during the immobilization process. The added nickel triggered the natural response of the cell, forcing the cell to produce its curli and making the cell sticky and easily attached to surfaces. This in turn further increased the cell immobilized by at least 50 %. The resulting enhanced-immobilized cell increases CGTase activity by 10 % and can be reused up to 10 cycles for CGTase expression and showed lower cell lysis compare to both the free cell and to the cell immobilized without any treatment. The optimization of starch direct conversion using the immobilized cell was done using the Box-Behnken design in the design expert software. Under the optimized condition, the highest yield of 15.45 mg/mL ß-CD was obtained, which was analysed using high performance liquid chromatography, and the immobilized cell was managed to be reused up to 6 cycles. Based on the results of this study, it can be concluded that the immobilization of E. coli was greatly enhanced by the combination of the two methods, ACh treatment and curli manipulation. Also, the enhancement resulted in less cell lysis and stronger cell attachment to the support material. The immobilized cell was successful in directly converting starch to ß-CD