Universiti Putra Malaysia
Download Latest Complete Journal - JST Vol. 25 (1) Jan. 2017
Foreword by the Chief Executive Editor
No.ArticlesDownloads
1
Full Article
(Downloads: 93)
Abstract (Viewed: 17)Preventive maintenance (PM) is a predetermined task that constitutes any maintenance actions performed before the quantity or quality of product equipment deteriorates. PM is primarily aimed at protecting assets, improving system reliability, and decreasing system downtime. Recently, the implementation of PM is becoming more challenging due to the increase in complexity of manufacturing systems. A case study on the effect of different parameters from a maintenance perspective on industrial shop floor performance is presented. The parameters include number of technicians, number of operations in each machine before maintenance actions, and volume of parts ordered by customers. This present research demonstrates the application of WITNESS simulation software to develop shop floor simulation model and the use of analysis of variance (ANOVA) to measure the significance of such parameters on performance. Analysis of Variance (ANOVA), models, parameters, performance measure, Preventive Maintenance (PM), WITNESS simulation software
2
Full Article
(Downloads: 58)
Abstract (Viewed: 6)Pineapple (Ananas Comosus), which has been identified as high-value non-seasonal tropic fruit, is one of the top five fruits in Malaysia that shows a promising demand in the local and export markets. The current study was conducted to analyse the efficiency energy inputs used in every activity involved in the process of pineapple production. The study also aimed to contribute in initiating a database for energy used in producing pineapples in Malaysia, which would hopefully become a guideline for applications in related policies in pineapple plantations. Data were collected based on direct field observations at a pineapple plantation under the management of Koperasi Serbaguna Anak-Anak Selangor Bhd. (KOSAS Bhd.) at Kg. Kundang in Selangor, Malaysia. Oral interviews were also carried out to gather any relevant information. The highest energy input used in pineapple production is fertiliser, contributing to 45.65% from the total energy equivalents used in the production. Fuel is the second highest energy source with a segment of 20.21% of the total energy, followed by planting material, agrochemicals, human labour and machine at 17.33%, 12.76%, 3.34 % and 0.69%, respectively. The ratio of energy output/inputs in pineapple production in the study area was 3.56. Conclusively, it means the energy input is effectively used in the pineapple production in the study area since the energy output/inputs ratio is greater than 1. Involvement of machinery in the pineapple cultivation practices in Malaysia is recommended since it reduces human drudgery and optimises farm"s capability to do work more efficiently and also to offset the labour shortage problem. Pineapple plantation, energy consumption, energy efficiency, sustainable agriculture, mechanisation
3
Full Article
(Downloads: 26)
Abstract (Viewed: 2)In this paper, a multi-objective analytical method to evaluate the impacts of optimal location and sizing of distributed generation is presented. This method is based on an analysis of the exact loss formula and continuous power flow in a radial distribution system. Based on two methods of analysis, power loss and weakest voltage buses and lines are calculated and then the optimal size of distributed generation is determined. After that, by considering the minimum power losses and the maximisation of voltage stability, the proposed index determines and ranks positions to decide the optimal distributed generation location in the system. This method allows us to find the best places and size to connect a number of distributed generation units by optimising the objective functions. The simulation results were obtained using a 33-bus radial distribution system to determine the location and size of the distributed generation units. The results show the effectiveness of voltage profile improvement, loading factor improvement and power loss reduction. Further, the problems of a single objective function and the placement of the distributed generation unit using analytical methods are solved by the proposed approach. Distributed generation, continuous power flow, voltage stability, exact loss formula, optimum size, optimum location
4
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(Downloads: 74)
Abstract (Viewed: 14)Adaptive Neuro Fuzzy Inference System (ANFIS) is among the most efficient classification and prediction modelling techniques used to develop accurate relationship between input and output parameters in different processes. This paper reports the design and evaluation of the classification performances of two discrete Adaptive Neuro Fuzzy Inference System models, ANFIS Matlab"s built-in model (ANFIS_ LSGD) and a newly ANFIS model with Levenberg-Marquardt algorithm (ANFIS_LSLM). Major steps were performed, which included classification using grid partitioning method, the ANFIS trained with least square estimates and backpropagation gradient descent method, as well as the ANFIS trained with Levenberg-Marquardt algorithm using finite difference technique for computation of a Jacobian matrix. The proposed ANFIS_LSLM model predicts the degree of patient"s heart disease with better, reliable and more accurate results. This is due to its new feature of index membership function that determines the unique membership functions in an ANFIS structure, which indexes them into a row-wise vector. In addition, an attempt was also done to specify the effectiveness of the model"s performance measuring accuracy, sensitivity and specificity. A comparison of the two models in terms of training and testing with the Statlog-Cleveland Heart Disease dataset have also been done. Adaptive neuro fuzzy inference system, Classification, Grid Partitioning Method, Levenberg- Marquardt algorithm, Prediction
5
Full Article
(Downloads: 23)
Abstract (Viewed: )Digital watermarking protocols are the one, which have combined fingerprinting technique with watermarking, for embedding digital signal or watermark into an original multimedia object. Buyer-seller watermarking protocol is fundamentally applied to continue the digital rights of both buyers and seller. We proposed an identity-based buyer-seller watermarking protocol that encounters various weaknesses of Zhang et al."s watermarking protocol. We ensured that by pointing out these weaknesses, inaccuracy can be minimised for further implementing the buyer-seller watermarking protocol. The suggested protocol uses ID-based public key cryptography and digital watermarking scheme to place the ownership of digital content. Hence, copyright protection is attained. We claim that our suggested protocol is efficient and has adequate security as compared to traditionally proposed protocols, and therefore suitable for any practical buyer-seller watermarking scheme. Digital content, Identity-based technique, Public key cryptography, Digital watermarking, Copyright protection
6
Full Article
(Downloads: 16)
Abstract (Viewed: 1)Credit risk assessment has become an important topic in financial risk administration. Fuzzy clustering analysis has been applied in credit scoring. Gustafson-Kessel (GK) algorithm has been utilised to cluster creditworthy customers as against non-creditworthy ones. A good clustering analysis implemented by good Initial Centres of clusters should be selected. To overcome this problem of Gustafson-Kessel (GK) algorithm, we proposed a modified version of Kohonen Network (KN) algorithm to select the initial centres. Utilising similar degree between points to get similarity density, and then by means of maximum density points selecting; the modified Kohonen Network method generate clustering initial centres to get more reasonable clustering results. The comparative was conducted using three credit scoring datasets: Australian, German and Taiwan. Internal and external indexes of validity clustering are computed and the proposed method was found to have the best performance in these three data sets. Credit Scoring, Decision-making, Clustering Techniques, Fuzzy Clustering Algorithms, Gustafson-Kessel Algorithm, Kohonen Network
7
Full Article
(Downloads: 30)
Abstract (Viewed: 3)This paper presents the technology of Active Radio Frequency Identification (RFID) and Wireless Mesh Sensor Network (WMSN) that will be used in agriculture. In this paper, ZigBee technology platform is applied in 2.45 GHz and active RFID to sustain the WSN by developing a fully automated IoT solution in agriculture for irrigation system. The system includes a plurality of sensor nodes installed in a crop field sending an ID, which are embedded sensor and WSN that work on ZigBee 2.4 GHz platform. The ID was sent to act as a signal of soil in dry condition of a specific area to a reader at base station. The pump stations will use information from base station to sprinkling water in the specific area of the dry state automatically. The automatic control system is very practical in agriculture but most of it is based on schedule and timer regardless of soil condition and temperature. Therefore, wireless automated irrigation system for efficient water use and production is proposed. WSN, RFID, ZigBee, Agriculture, Sensor
8
Full Article
(Downloads: 25)
Abstract (Viewed: 1)An incorporation of waste tyre particles in concrete has been established to produce a green concrete. However, despite its advantages, strength reduction is an obvious handicap. To improve the strength, pre-treatments of the waste tyre particles and addition of Oil Palm Fruit Fibre (OPFF) were chosen and reported in this study. The addition of OPFF was to influence the internal structure in order to improve shrinkage and other strength properties. Performance of the composites in compressive, split tensile and flexural strengths, as well as shrinkage and microstructure were observed. Results showed better behaviour of the treated tyre crumb mortar rather compared to the untreated tyre, with the replacement of up to 40% by volume of the treated tyre crumb particles and 0.5- 1.0% OPFF addition by mass of cement content. Lightweight aggregates, treated, untreated, tyre crumb, oil palm fruit fibre, mechanical properties, unrestrained shrinkage
9
Full Article
(Downloads: 26)
Abstract (Viewed: 2)The present study aimed to examine the levels of diabetes knowledge, attitudes, self-management and quality of life (QoL) between two countries with different cultural and language backgrounds. Data collection was conducted in two hospitals in Melbourne, Australia, and a hospital in Kelantan, Malaysia. Participants with type 2 diabetes mellitus (T2DM) were asked to complete four questionnaires, measuring diabetes knowledge, attitudes, self-management, and QoL. The differences between the samples were examined using chi-square and independent samples t-tests. The variables of gender and type of treatment (using insulin or not using insulin for treatment) based on groups were analysed using one-way ANOVA. All analyses were conducted using SPSS 22.0. The results highlighted some similarities and differences between the Australia-based sample and the Malaysia-based sample. In general, the Australia-based participants scored significantly higher in diabetes knowledge and reported more regular self-management of T2DM in exercise, blood glucose testing and foot care. The Australia-based sample also scored higher on attitudes compared to the Malaysia-based participants. On the other hand, Malaysia-based participants reported a lower level of impacts of T2DM on QoL. There was no significant difference between self-management of T2DM in terms of diet and satisfaction as an aspect of QoL related to living with diabetes between the two samples. The present study highlighted the levels of diabetes knowledge, attitudes, self-management, and QoL among Australia-based and Malaysia-based people with T2DM. Type 2 diabetes mellitus, knowledge, attitudes, self-management, quality of life, insulin, gender
10
Full Article
(Downloads: 18)
Abstract (Viewed: 2)In this study, a hybrid approach that employs Hopfield neural network and a genetic algorithm in doing k-SAT problems was proposed. The Hopfield neural network was used to minimise logical inconsistency in interpreting logic clauses or programme. Hybrid optimisation made use of the global convergence advantage of the genetic algorithm to deal with learning complexity in the Hopfield network. The simulation incorporated with genetic algorithm and exhaustive search method with different k-Satisfiability (k-SAT) problems, namely, the Horn-Satisfiability (HORN-SAT), 2-Satisfiability (2-SAT) and 3-Satisfiability (3-SAT) will be developed by using Microsoft Visual C++ 2010 Express Software. The performance of both searching techniques was evaluated based on global minima ratio, hamming distance and computation time. Simulated results suggested that the genetic algorithm outperformed exhaustive search in doing k-SAT logic programming in the Hopfield network. Genetic Algorithm, Exhaustive Search, Hopfield network, Satisfiability, Logic Programming, HORN-SAT, 3-SAT, 2-SAT
11
Full Article
(Downloads: 17)
Abstract (Viewed: 3)Renewable energy projects in many developing countries need financial and legal back up from governments and other supportive bodies. There is a viable alternative to finite energy via usage of biomass waste a renewable energy source. The electrical energy production analysis on biomass waste presented in this paper is based on the experimental analysis carried out using the laboratory and pilot scale bioreactors. Electrical energy generated with oscillatory flow bioreactor (OFBR) was 10.12 kWh or up to 91% higher than the 10 L lab scale bioreactor (0.9 kWh), demonstrating that the novel OFBR has a great potential for renewable electricity. Also, the pilot scale plant achieves a value of 12.3 kWh, which the difference is not quite significant with that of OFBR. These results illustrate that the generation of the renewable electricity is feasible especially with the OFBR thereby achieving high methane potential during the treatment of manure and food waste. Nevertheless, energy recoveries should be enhanced to improve the entire operational performance. Biogas, electrical power generation, methane production, renewable energy
12
Full Article
(Downloads: 20)
Abstract (Viewed: 2)The feasibility of an anaerobic digestion of cattle manure for biogas production is studied in this paper. A batch thermophilic oscillatory flow anaerobic bioreactor (OFBR) operated in thermophilic (55oC) condition was used. Within the experimental conditions set in this study, the effect of mixing intensity on volatile solids removal was found out to be significant. Results demonstrated that increasing the level of mixing decreased the digester performance. Low intensity mixing at oscillatory Reynolds number (Reo) of 100 achieved an increase of 37% in biogas yields compared to high mixing intensity, Reo of 500. It was observed that the mixing intensity effect interacts with the methane composition in the biogas. The benefit of decreasing mixing intensity emerges to significantly increase the methane composition in the biogas. These experiments established that high intensity mixing was not essential for good performance of oscillatory flow anaerobic bioreactor. In addition, the effect of mixing intensity might be reduced through the use of a slightly lower total solid concentration, hence, lowering the operational cost of the process. Although the study was lab scale a pilot-scale system where mixing retention times are longer would be useful. Anaerobic digestion, biogas, cattle manure, mixing intensity, oscillatory flow mixing
13
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(Downloads: 20)
Abstract (Viewed: 2)In 2013, 632 602 private cars were involved in road crashes, this amounting to 64% of all road crashes on Malaysian roads. Risk is often used to quantifying the level of road safety whilst exposure is an essential component of risk measurement. The calculation of VKT (vehicle kilometre travel) in this study using odometer reading data obtained from automobile manufacturer is used for cars. This average in 2013 was 24,129 kilometres, the highest recorded in Selangor with 28,575 kilometres and the lowest at 16,342 kilometres a year, in Johor. This method is believed to be reliable with a high yielding number of samples as well as a good representative set of samples for Malaysia. Average annual kilometre travelled, car, fatality index, motorcar, vehicle kilometre travelled
14
Full Article
(Downloads: 17)
Abstract (Viewed: 2)CCTV surveillance systems are widely used as a street monitoring tool in public and private areas. This paper presents a novel approach of an intelligent surveillance system that consists of adaptive background modelling, optimal trade-off features tracking and detected moving objects classification. The proposed system is designed to work in real-time. Experimental results show that the proposed background modelling algorithms are able to reconstruct the background correctly and handle illumination and adverse weather that modifies the background. For the tracking algorithm, the effectiveness between colour, edge and texture features for target and candidate blobs were analysed. Finally, it is also demonstrated that the proposed object classification algorithm performs well with different classes of moving objects such as, cars, motorcycles and pedestrians. Adaptive background modelling, distributed cameras tracking, object detection, object classification, intelligent surveillance
15
Full Article
(Downloads: 18)
Abstract (Viewed: 2)Experimental data from a physical model of scouring around a cylindrical wide pier embedded in two types of uniform sediment beds are presented. The effects of sediment sizes and various pier widths on scour development and equilibrium scour depth of wide bridge piers are described. Existing literature suggest that the empirical scour prediction equations based on laboratory data over-predict scour depths for large structures. The present study has attempted to fill this gap for a cylindrical wide pier. Further, equations for the estimation of non-dimensional maximum scour depth for a wide cylindrical pier embedded in uniform sediment were proposed as functions of the sediment coarseness. Physical model, scour, wide piers, uniform sediment, sediment coarseness
16
Full Article
(Downloads: 17)
Abstract (Viewed: 2)Manual Material Handling (MMH) involves lifting, bending, and twisting motions of the torso. Poor lifting technique is often considered a major risk factor in low back injury associated with manual lifting tasks. Currently, there is little work on the effects of lifting on the Malaysian population. The MMH activities that was designed with the different lifting heights, frequency, weight of loads and the effect on of biceps and triceps muscle contraction of the subjects during the lifting tasks were studied. The parameters involved are weight of the loads lifted, height of the loads lifted and lifting frequency as the independent variables. Whereas the dependent variable is Electromyography (EMG) signal. The weight loads are varying from 10kg up to 24kg and the heights of the loads travels from the floor to 70cm and 130cm heights. The frequency of lifting is set to 1 lift and 6 lifts per minute. 14 healthy male and female subjects were recruited in this study. The questionnaires and consent form were used to identify the health condition of the subjects before performing the lifting tasks. The EMG activity was recorded and collected from biceps and triceps muscles using the Shimmer EMG system. This method is used in determining the maximum acceptable weight limit (MAWL) that can be lifted by the subjects in the lifting tasks. This research aims to design a lifting equation that suits for Malaysian people. Therefore, the effects of different manual lifting tasks on Malaysian physiological limits need to be identified. Electromyography, frequency, height, lifting tasks, load
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(Downloads: 17)
Abstract (Viewed: 3)The effect of osmotic stress was carried out to determine the resistance to salt toxicity using 4 Continuous Stirred Tank Reactor (CSTR). A CSTR digestion study revealed that digesters seeded with an inoculum from a conventional mesophilic digester treating municipal wastewater and fed on domestic wastewater (DW) plus salts were able to acclimate successfully to a final salt concentration of 10 g l-1. The digesters showed some disturbances during the acclimatisation period as indicated by reductions in specific methane production (SMP), specific biogas production (SBP), pH and increases in Intermediate Alkalinity /Partial Alkalinity (1A/PA) ratio and Volatile Fatty Acid (VFA) concentration. This study revealed the order of disturbance was Sodium Chloride (NaCl) > Potassium Chloride (KCl) > KCl + NaCl. The average values for SMP after stabilisation were below those in the controlled digester, at 0.335 (controlled), 0.323 (NaCl), 0.316 (KCl + NaCl) and 0.308 l CH4 g-1 COD added (KCl). Adaptation, chemical oxygen demand, inhibition, osmoregulation theory, specific methane production
18
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(Downloads: 17)
Abstract (Viewed: 1)Rapid developments in the design of chips and electronic devices for high-performance computers have necessitated new and more effective methods of chip cooling. The purpose of this study was to investigate the heat transfer characteristics of aluminium foam heat sink for the Intel core i7 processor. Three aluminium foam heat sink models were used in the study: without channels (A), with two channels (B), and with three channels (C). The aluminium foam heat sink was subjected to a steady flow of water covering the non-Darcy flow regime (541 to 1353 Reynolds numbers). The bottom side of the heat sink was heated with a heat flux between 8.5 and 13.8 W/cm2. The distributions of the local surface temperature and the local Nusselt number were measured and compared with numerical data obtained using the finite element method for all three models. The average Nusselt number was obtained for the specified range of Reynolds numbers, and an empirical correlation of the average Nusselt number as a function of the Reynolds number was derived for each model. The results revealed that the local surface temperature increases as the heat flux increases, decreasing the Reynolds number and increasing the flow direction axis for all three models. Model (A) achieved a lower local temperature than models (B) and (C). Compared with model (A), models (B) and (C) reduced the average Nusselt number by 10% and 25%, respectively. The pressure drop across the foam was also measured. The thermal efficiency index was defined in this study in order to obtain the optimal design condition for the aluminium foam heat sink models. The results revealed that the optimum design condition is model (B) at Re=1353. The numerical results were in good agreement with the local Nusselt number and the local experimental temperature with a maximum relative error of 3% and 2% respectively. Electronic cooling, forced convection, porous media, heat transfer, heat sink, metal foam
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(Downloads: 17)
Abstract (Viewed: 1)In this study, we investigated the anisotropic Li diffusion in Li10GeP2S12 using a molecular dynamics method. Although the calculated ion conductivity is slightly lower in comparison to the calculated and experimental ion conductivity of previous studies, our results support anisotropic Li diffusion. These findings show that the anisotropic Li diffusion estimated from the activation energy is an important property of Li10GeP2S12, and a potential factor for good ion conductivity. Further, a high diffusion coefficient was observed in Li10P3S12, which is a good Li-ion conductor. Solid electrolytes, Li10GeP2S12, molecular dynamics simulation, Li-ion battery, activation energy, ion conductivity
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(Downloads: 23)
Abstract (Viewed: 1)This paper focuses on examining the "cutting zone temperature" while performing turning operation on AZ91Mg alloy using cemented carbide tools. The regression model is developed by using the RSM techniques based on experimental results. It is revealed that the cutting speed (v) is the most dominant factor affecting cutting zone temperature. The developed models of cutting zone temperature sufficiently map within the range of the turning conditions considered. The adequacy and accuracy of the regression equation is justified through ANOVA. It is found that the optimal combinations of machining parameters minimize the cutting temperature. ANOVA, Cutting temperature, Magnesium, Optimization, Turning and Response surface methodology
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(Downloads: 15)
Abstract (Viewed: 1)A maximal complete subgraph of G is a clique. The minimum (maximum) clique number ?=?(G) (?=?(G)) is the order of a minimum (maximum) clique of G. A graph G is clique regular if every clique is of the same order. Two vertices are said to dominate each other if they are adjacent. A set S is a dominating set if every vertex in V- S is dominated by a vertex in S. Two vertices are independent if they are not adjacent. The independent domination number i=i(G) is the order of a minimum independent dominating set of G. The order of a maximum independent set is the independence number ß_0=ß_0 (G). A graph G is well covered if i(G)=ß_0 (G). In this paper it is proved that a graph G is well covered if and only if G ¯ is clique regular. We also show that ?(G ¯ )=i(G). Clique, Minimum clique number, Maximum clique number, Domination number, Well covered graphs and clique regular graphs
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(Downloads: 21)
Abstract (Viewed: 2)Filters are the basic part in wired, and wireless telecommunications and radar system circuits and they play an important role in determining the cost and performance of a system. The increasing demand for high performance in the fields of RF, WLAN, WiMAX and other wireless communications led to the great revolution in the advancement of the development of a compact microstrip resonator filter design. All these have made a vital contribution to both the required performance specifications for filters and other commercial requirements in terms of low cost, large storage capacity and high-speed performance. This review paper presents several design examples for multi-band, multi - mode microstrip filter resonators to satisfy RF, WLAN, WiMAX, UWB and other wireless communication frequency bands. To analyse the resonant frequencies odd - mode and even -modes can be used for the symmetrical structure. In general, the multi-mode resonators can be designed by using different methods like cross-coupling resonators Structure, and the allocation of the fundamental resonant frequencies of the resonator as stated by the Chebyshev"s insertion loss function. Wireless telecommunication, WLAN, WiMAX, (SIR) filter, multi - mode resonators, UWB (Ultra-Wide Band), cross-coupling resonators
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(Downloads: 16)
Abstract (Viewed: 3)This paper presents an improved version of a wireless device embedded with a smart PZT sensor to detect flaws and structural defects on selected investigated structure. Smart PZT sensors were used as an actuator and sensor, coupled with two XBee"s and one signal generator IC chip. Programme execution on transmitting and receiving the ultrasonic guided wave via the PZT sensor had been written in MATLAB. The developed source code is basically to receive serial data from one Xbee to another remote Xbee attached to the investigated structural system. The refined waveform response is utilised for prognosis of the true structural status. The 4-mm simulated holed into one of the aluminium structural plate is benchmarked with its pristine condition in validating the effectiveness of the developed SHM wireless module. Results showed that the wave is more even in non-defected area and disrupted in affected area. Ultrasonic waves increase continuously for non-destructive evaluation and structural health monitoring in various structural applications because the guided wave can propagate long distances and reach difficult-to-access regions; for inspecting porous and some non-porous materials ultrasonic waves attenuate fast and are very useful. Recent advances in ultrasonic wave application model and results are discussed in this paper. microcontroller, piezoelectric sensor, sine wave signal, smart sensor, structural health monitoring, wireless sensor
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(Downloads: 15)
Abstract (Viewed: 2)All buoyant and hybrid buoyant aerial vehicles have directional stability issues at low speed. Electric trimmers are one of the potential solutions for controlling the yaw motion of such vehicles in which partial lift is obtained from the wings. However, available propeller disk area of such trimmers is limited due to small surface area of the vertical tail. In the present work, maximum input power required by thin electric propellers with different pitch values are compared to obtain an optimised value of pitch for propeller selection. Analytical as well as computational techniques are employed to evaluate the moment generated by tangential thrust produced by a ducted propeller. Motocalc® software under predicts the thrust value when compared with the computational results under the same flow conditions. The estimated yaw force produced by the propeller is quite significant and it can also be used for creating differential thrust using twin electric motors. Advance Ratio, Computational Fluid Dynamics, Hybrid Buoyant Aerial Vehicle, Static Thrust, Turning, Thin Electric Propeller
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(Downloads: 15)
Abstract (Viewed: 3)This paper presents experimental findings derived from high velocity impact tests on woven-roving Glass Fibre-Reinforced Polymers (GFRP) Type E-800 g/m² and Type C-600 g/m². The effects on specimen thickness, projectile shape and gas gun pressure were investigated. As the gas gun pressure increases, there is a proportional increase in the projectile kinetic energy, the projectile initial velocity, the maximum force exerted on the specimens and in energy absorption upon impact. During the test, the shape of the projectile, the target thickness and the gas gun pressure significantly affected the impact performance of the GFRP. From the experiment, it was found that GFRP Type E-800 g/m² is stronger and more impact resistant compared with GFRP Type C-600 g/m², due to the fact that E-glass materials have higher fibre volume and density and overall better mechanical properties than C-glass fibres. Therefore, GFRP Type E-800 g/m² composites should be considered for applications in load and impact bearing aircraft structures. Energy Absorption, Glass Fiber Reinforced Polymer (GFRP), High Velocity Impact (HVI), Impact Characterisation, Polymer Matrix Composites (PMC), Single Stage Gas Gun (SSGG)
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(Downloads: 18)
Abstract (Viewed: 2)Composite structures and materials are used in aerospace, marine and automotive applications due to their light weight characteristics. By using rice husk ash (RHA) as natural binder to replace epoxy resin, it improves the characteristic of the composite laminated structure. Rice husk has become an important ingredient in silica, silicon carbide, and silicon nitride because of its high a silicon content. This paper evaluates the performance of laminated composite plate in a drop-weight impact testing. Two plates are attached to the test rig in the particular desired impact orientation. The main advantages of this process are the plates provide more realistic drop-weight impact and data. Data from the impact test was collected and analysed to evaluate the material properties of epoxy resin and RHA. Results show RHA"s energy absorption is better and it has more deformation to prevent structure failures compared with epoxy resin. This paper aims to evaluate the application of RHA as a geopolymer binder and flax fibre as an alternative material to glass fibre in the composites industry. Laminated Composite Plate, Geopolymer Binder, Drop-Weight Impact Test, Rice Husk Ash (RHA), Flax Fibre, Fibre Glass
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(Downloads: 18)
Abstract (Viewed: 2)The influence of elevated germanium concentration on the thermoluminesence characteristics of a novel form of fabricated flat optical fibre was examined. All the samples were irradiated with two nominal photon energies (6 MV and 10 MV) and 1.25 MeV gamma energy. Flat fibres with 10 mol % Ge concentration provided the superior TL yield compared against that of 6 and 8 mol % Ge-doped optical fibres for both 6 MV and 10 MV energy. Interpretation of the results has been aided by study of the glow curves, revealing in particular new generation of defects in the flat fibres due to strain-generation at the collapsed surfaces. The strain represent deep-energy defects. Dosimetric characteristics, flat fibre, glow curves
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(Downloads: 23)
Abstract (Viewed: 3)Adnexal masses are growths that form near the uterus; the majority being ovarian tumours. Although there is no established population-screening tool for detecting ovarian cancer, ultrasound and contrast-enhanced computed tomography (CECT) are useful imaging tools in the management of adnexal masses. Our study aimed to determine the characteristics of malignant adnexal masses on CECT scan and to describe common pitfalls in diagnosis of ovarian cancer when interpreting images. We also determined the sensitivity and specificity of diagnosing ovarian cancer using CECT. A retrospective study was conducted in Hospital Serdang using data from all patients who underwent CECT scan and detected with adnexal masses, and had histopathological examination correlation from January 2013 until January 2015. Out of the 64 cases analysed; the majority of malignant lesions were serous carcinoma of the ovary (40%). The CECT scan characteristics, tumour consistency of mixed type, presence of wall enhancement, septations, ascites and peritoneal nodule/omental caking were significantly associated with ovarian malignancy (p<0.05). The sensitivity, specificity, PPV and NPV of CECT scan was 95.45%, 71.43%, 63.63% and 96.77% respectively. Contrast-enhanced computed tomography scan is a good, non-invasive method to diagnose ovarian cancer. By using a pro-forma document as a guide, good results can be achieved to help differentiate between benign and malignant lesions. Nevertheless, caution needs to be exercised in interpreting cases that mimic features of malignancy. Accuracy, computed tomography, diagnosis, ovarian cancer
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(Downloads: 18)
Abstract (Viewed: 1)Chronic Lymphocytic Lymphoma (CLL) may transform into an aggressive high grade variant in approximately 4-6% of cases known as Richter"s Transformation (RT). Cutaneous lymphoma as well as other high-grade lymphomas may be a rare presentation of RT. As minimally invasive cosmetic procedures increase in popularity, we present an important mimicker of cutaneous uptake of the lower face simulating RT in a patient with CLL, after the injection of collagen fillers and botulinum toxin A (Botox) to the lower face. To our knowledge there are no previous studies on this important observation. Reading physicians should be cognisant of this masquerade to prevent misdiagnosis. Botox, mimicker, PET/CT, Richter"s Transformation
30
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(Downloads: 27)
Abstract (Viewed: 5)The use of prenatal ultrasound has become controversial as it is increasingly being performed for business and social interests rather than for medical use. This nonmedical use of the modality has violated the US FDA guideline. Ultrasound scans have been proven to increase temperature in insonated tissue and their effects have been investigated via phantom and animal experiments. Absorption coefficient of the bone is the highest compared with any other structure. Thus, exposure to ultrasound, especially during osteogenesis, can cause significant damage to developing foetus. Twenty-two pregnant does of known gestation were enrolled in the control and experimental groups. No exposure was given to the control group while the experimental groups were exposed accordingly to the prenatal ultrasound in the 1st, 2nd and 3rd stage for 30, 60 and 90 minutes respectively. A total of 142 subjects aged between 1 and 5 months were analysed for bone strength. The Tb.Th of the experimental group was reduced significantly as compared to the control group. Po, TMD and empty lacunae were higher in the experimental group. It is thus concluded that one-time prenatal ultrasound can affect bone strength in young subjects. Bone histology, bone morphology, bone strength, prenatal ultrasound, tissue mineral density, young age
31
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(Downloads: 25)
Abstract (Viewed: 4)Popliteal artery injury is the most disastrous intraoperative complication during total knee replacement. This study aims to determine the mean distance between the popliteal artery (PA) and the tibial plateau in normal and osteoarthritic patients who underwent Dual Energy CT Angiography (CTA) of the lower limb. Materials and Methods: All CTA lower limb examinations from January 2013 to October 2014 were retrospectively reviewed. The distance between the PA the tibial plateau distance and the thickness of popliteus muscle were electronically measured. We used modified Kellgren and Lawrence"s Classification to grade the osteoarthritis in patients who underwent CT examinations regardless of symptoms. Results: There were a total of 126 patients who underwent CTA (93 males and 33 females). 54 of them were Malays, 47 Indians, and 24 Chinese. The mean age of patients was 58 years (range 16 to 92). The mean PA-to-tibial plateau distance was 9.9 mm for the right lower limb (range 2.5 mm to 17.2 mm) and 10.24 mm for the left (range 5.5 mm to 15.4 mm). There were no significant correlations between PA-to-tibial plateau distance with osteoarthritis grade, age, gender, and racial origin (P > 0.05); however, there was a positive correlation between PA-to-tibial plateau distances with popliteus muscle thickness (P = 0.000). Conclusion: Osteoarthritic condition in the knee does not reduce the popliteal artery to the tibial plateau distance. Hence, a higher osteoarthritic grade does not impose additional risks with regards to popliteal artery to tibial plateau distance, with relatively similar arterial injury risks compared to normal knees. Radiology, popliteal artery, osteoarthritic

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