Waste to Valuable By-product: Palm Oil Mill Decanter Cake and its Ability to Remove Cd, Cu and Pb Ions

Palm oil mills generate about 4 - 5 tons of decanter cake for every 100 tons of palm fresh fruit bunch processed. Due to the high organic content, the decanter cake could be converted into adsorbent for the removal of metal ions from waste water. The decanter cake was first dried at 105 oC and then carbonized at various temperatures. The resulting carbonized decanter cake were tested for removing cadmium (II), copper (II), and lead (II) ions. Proximate analysis using thermogravimetry of decanter cake carbonized at 500 oC indicated that the adsorbent contained 4% moisture, 21% volatile,23% fixed carbon, and 52% ash. Adsorption test was carried out by mixing 1.0 g of the decanter cake in 100 mL aqueous solution of the various ions. The concentration of metal ions in the solutions used is in the range of 100 – 1000 mg/L. The results of adsorption studies indicated that the removal of metal ions was highest in the case of Pb when the carbonization temperature was 500 oC and 600 oC in the case of Cd and Cu. Maximum removal of the Cd, Cu and Pb were also observed to take place when the pH of the solution is in the range of 4 – 5. Langmuir and Freundlich isotherm models were used to fit the isotherm experimental data. The maximum uptakes of Cd, Cu and Pb onto the carbonized decanter cake in this study were estimated to be 24, 23, and 97 mg/g respectively. The ability of the carbonized decanter cake to remove the metal ions was found to be comparable to that of other adsorbents derived from agricultural waste

Microcrystalline Cellulose (MCC) from Oil Palm Empty Fruit Bunch (EFB) Fiber via Simultaneous Ultrasonic and Alkali Treatment

In this study, microcrystalline cellulose (MCC) was extracted from oil palm empty fruit bunch (EFB) cellulose which was earlier isolated from oil palm EFB fibre. In order to isolate the cellulose, the chlorination method was carried out. Then, the MCC was prepared by simultaneous ultrasonic and alkali treatment from the isolated α-cellulose. Based on mass balance calculation, the yields for MCC obtained from EFB was 44%. For fiber characterization, it is observed that the chemical composition of the hemicellulose and lignin for all samples decreased while composition for cellulose increased. The structural property of the MCC was studied by X-ray diffraction (XRD) method and the result shows that the MCC produced is a cellulose-I polymorph, with 73% crystallinity

PHASE CO-ORDINATE BOND GRAPH ANALYSIS OF MULTIPORT ENERGY SYSTEMS

PhDThe analysis of unbalanced power system problems using the method of phase co-ordinates by which the phase quantities are preserved has obvious practical advantages over the transformation methods requiring the phase quantities to be substituted by, for example, symmetrical component and d-q quantities. Since the physical identity of the system is maintained in the phase frame of reference, the matematical models of the system can be subjected to actual operating constraints enabling a unified approach to be adopted in the study of both symmetrical and unsymmetrical conditions. In this thesis the bond graph techniques are used to model power system components in terms of their phase co-ordinates. The bond graph structure, which is based on energy continuity and power balance, classifies system and sub-systems, with respect to the number of energy ports through which energy or power is exchanged with the environment as well as in terms of the particular internal energy transformations involved. The use of bond graphs for the analysis of non-linear electromagnetic systems has resulted in the evolution of a uniform diagramatic structure which, represents in a single diagram the basic field properties such as the magneto-motive force and the flux linkages together with the conjugate circuit power variables, voltage and current. As an extension of this ideal the general n-port electromagnetic and electrostatic field systems are derived in bond graph notations. A very desirable feature of this method of presentation is that there exists a one-to-one-correspondence between the bond graph and a computation structure which may be used for the purpose of simulation by either analogue or digital computers. The general n-port electromagnetic and electrostatic field systems form the basis for the effective modelling of power system components such as rotating machines, transformers and transmission lines. In the investigations of earth faults, these models are simplified in accordance with the need of the particular study but are sufficiently accurate representations to allow predictions on the overall system behaviours. The bond graph approach is ideally suited to expedite the modelling of dynamic interacting energy systems and when used in conjunction with the computation structure can provide the simulation technique required to model accurately the non-linear behaviours of multiport electromechanical energy converters. The effects of magnetic saturation in synchronous generators are presented in detail.Institut Teknologi Kebangsaan, Malaysi

A Carrierless Amplitude Phase (CAP) Modulation Format: Perspective and Prospect in Optical Transmission System

The explosive demand of broadband services nowadays requires data communication systems to have intensive capacity which subsequently increases the need for higher data rate as well. Although implementation of multiple wavelengths channels can be used (e.g. 4 × 25.8 Gb/s for 100 Gb/s connection) for such desired system, it usually leads to cost increment issue which is caused by employment of multiple optical components. Therefore, implementation of advanced modulation format using a single wavelength channel has become a preference to increase spectral efficiency by increasing the data rate for a given transmission system bandwidth. Conventional advanced modulation format however, involves a degree of complexity and costly transmission system. Hence, carrierless amplitude phase (CAP) modulation format has emerged as a promising advanced modulation format candidate due to spectral efficiency improvement ability with reduction of optical transceiver complexity and cost. The intriguing properties of CAP modulation format are reviewed as an attractive prospect in optical transmission system applications

Multiple-Objective Optimization Techniques in Laser Joining of Dissimilar Materials Classes: A Comparison between Grey and Ratio Analyses

Multiple-objective optimization using grey relational analysis (GRA) has found widespread applications especially in manufacturing and machining processes that involve complex processing parameters and output attributes. On the other hand, multiple-objective optimization on the basis of ratio analysis (MOORA) is often applied in the fields of construction and economy. One distinctive feature of MOORA is the assessment of relative importance of all responses (i.e. weighting ratio) which are taken into account mathematically while GRA emphasis the need of a priori information for accurate assignment of weighting ratio. This paper compares these two seemingly different methods by considering their applications in laser joining of dissimilar materials classes in a number of case studies: (a) laser joining of polymer and ceramic, (b) laser joining of polymer and stainless steel, and (c) laser joining of polymer and aluminium alloy. The outcomes of the two methods are compared and discussed. In majority of the cases, the predicted top-ranked alternatives were comparably matched. It is concluded that MOORA is more favourable compared to GRA since it eliminates prior assumption concerning the relative importance of the measured responses, which can lead to unnecessary bias

Task mapping and routing optimization for hard real-time Networks-on-Chip

Interference from high priority tasks and messages in a hard real-time Networks-on-Chip (NoC) create computation and communication delays. As the delays increase in number, maintaining the system’s schedulability become difficult. In order to overcome the problem, one way is to reduce interference in the NoC by changing task mapping and network routing. Some population-based heuristics evaluate the worst-case response times of tasks and messages based on the schedulability analysis, but requires a significant amount of optimization time to complete due to the complexity of the evaluation function. In this paper, we propose an optimization technique that explore both parameters simultaneously with the aim to meet the schedulability of the system, hence reducing the optimization time. One of the advantages from our approach is the unrepeated call to the evaluation function, which is unaddressed in the heuristics that configure design parameters in stages. The results show that a schedulable configuration can be found from the large design space

Synergistic effects of Persicaria odorata (Daun Kesom) leaf extracts with standard antibiotics on pathogenic bacteria

Antibacterial activity of different types of P. odorata leaf extracts was evaluated in combination with standard antibiotics. Persicaria. odorata leaves were extracted with n-hexane (n-hex), dichloromethane (DCM) and methanol (MeOH). Each extract was applied on vancomycin (30μg), erythromycin (15μg) and gentamicin (10μg) discs, respectively. Disk diffusion method was used to evaluate the synergistic activity of each combination on Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli. Minimum inhibitory concentration (MIC) and gas chromatography mass spectrometry (GCMS) analysis was performed on the active extract. Synergistic effects seen were mainly from the n-hex+antibiotics combinations, mainly on the Gram-positive bacteria (7 additive, 5 antagonistic), with MIC range from 50 μg/ml to 100 μg/ml, as well as Gram-negative bacteria (2 additive, 2 indifferent, 5 antagonistic). In particular, synergism showed by the combination of n-hex+van were all additive against the susceptible bacteria. DCM extract combination showed synergistic effects on three Gram-positive species (S. aureus, S. epidermidis, S. pyogenes). Meanwhile, MeOH+antibiotics combination showed significant additive synergistic effects (p<0.05) on S. aureus and S. epidermidis. The major compounds of leaves extract were decanal and β-citral. n-Hex extract superiorly inhibited Gram-positive bacteria growth as compared to DCM and MeOH extracts. The additive synergistic property of the n-hex P. odorata extract could be further studied for possible use as an antibacterial agent

Effect of pour point depressant (PPD) and the nanoparticles on the wax deposition, viscosity and shear stress for Malaysian crude oil

Formation of wax can cause increase of pressure drop, blockages in the pipelines and interference with valve and instrumentation operation that causes loss of billions of dollars. Pour point depressant (PPD) is one of the wax treatment technique used widely in oil industry to alter the crude oil properties such as viscosity, wax appearance temperature (WAT) and pour point. The performance of PPD and nanoparticle, sodium cloisite Na + was analyzed in this study, to identify their impacts on viscosity, shear stress and wax deposition of the Malaysian crude oil using Brookfield DV-III viscometer and cold finger equipment respectively. The viscosity was successfully reduced by 4% and 8% when the crude oil is treated with PPD and PPD/Nanoparticle blend respectively. Cold finger temperature, experimental duration and rotation rate of impeller affects the efficiency of PPD and PPD/Nanoparticle blend. Cold finger temperature at 15 °C provides the highest PIE of 88.27% with the usage of PPD/Nanoparticle blend. Therefore, PPD/Nanoparticle blend able to reduce the viscosity efficiently and gives higher PIE compare than PPD

Directional felling within selective management system of Peninsular Malaysia: comparison between current and extended techniques

Directional felling has been implemented in Peninsular Malaysia as part of the Selective Management System (SMS) to obtain optimum yield from the forest resources while reducing damage to the environment and residual trees. Some questions regarding its effectiveness have been questioned a few times, resulting in a joint research project at Ulu Jelai Forest Reserve, Pahang, Malaysia to compare between the current directional felling technique and the new (extended) techniques, in terms of accuracy of tree felling, volume of felling logs, expected damage on residual trees, and time taken for tree felling. For this study, 38 trees were felled with the current and extended techniques. By using the extended technique, 91.3% of the trees were felled within the 0°-5° range, and 100% within the 0°-10° range, compared to 28.01% (within the 0°-5° range) using the current technique. The extended technique also recorded higher volume recovery (14% higher) and lower damage on the residual trees by almost 50%. However, the extended technique took longer time, i.e. 4.56 minutes per tree, as compared to 2.50 minutes. The main contributor to the difference is the presence of gauge cut in the extended technique. Generally, the studies suggest that the extended technique is preferred as it is safer to the feller and surrounding people, while reducing the collateral damage on the harvested trees, as well as the residual trees