After ABO, Rhesus (Rh) is the second most clinically important blood group regarding transfusion and pregnancy induced alloimmunisation. RhD DEL is a subtype of variant RhD, which is difficult to determine in a routine blood bank, since it expresses an extremely low level of D antigens. Serologically, it can only be detected via adsorption-elution test. To date, there have been limited data available on the Rhd DEL phenotype in Malaysia. Thus, this study was carried out to detect DEL phenotype among RhD negative donors in Malaysia. A total of 43 RhD-negative blood samples were collected from National Blood Centre, Malaysia. Rh phenotype for each sample was tested, followed by adsorption elution technique. Then, identification of DEL carrying RHD1227A allele was performed via SSP-PCR. Rh-phenotype identified were ccee (79.07%), Ccee (13.95%), 4.65% of ccEe phenotype and only 2.33% of CCee phenotype. One (2.3%) out of the 43 samples was identified as DEL phenotype carrying RHD1227A allele when tested using SSP-PCR, but none was identified from adsorption-elution. A larger sample size is recommended to determine the exact prevalence of DEL phenotype, as well as specificity and sensitivity between SSP-PCR as compared with the traditional adsorption elution technique.
Temporal distribution of forecasted wind speed is important to assess wind capacity for wind-related technology purposes. Regional wind energy estimation needs the development of wind pattern to monitor and forecast temporal wind behaviour. Temporal wind in Malaysia mainly depends on monsoonal factor that circulates yearly and each monsoon derives distinct character of wind. This paper aims to develop a model of wind speed pattern from historical wind speed data. Then, the model was used to forecast 5-years seasonal wind speed and identify temporal distribution. Wind speed model development and forecast was performed by identifying the best combination of wind speed seasonal component using Seasonal Auto-regressive and Moving Average (SARIMA) model. Thus, three distribution models, Lognormal, Weibull and Gamma models, were exploited to further observe consistency using Kolmogorov-Smirnov goodness-of-fit test. The best fit model to represent seasonal wind distribution in each monsoon season at Pulau Langkawi, Malaysia, is Log-normal distribution (0.04679-0.108).
Aspergillus sp. is an extremely resilient species that can be found everywhere in the environment and is present abundantly in water and soil. The defining characteristic of Aspergillus sp. is their extensive hyphal network which enable them to survive anywhere, even in very harsh conditions. This study was carried out to isolate the filamentous fungi from peat soil of animal agricultural farm and characterise them based on their morphological and molecular characteristics. Growth rate of each isolated fungi was also evaluated in order to determine the period of maturity for each fungi. Soil samples were collected, weighed and then dissolved in sterile distilled water. The samples were serially diluted and spread onto potato dextrose agar (PDA) for isolation. Different isolated colonies that were morphologically different from each plate was purified and sub-cultured onto new media for macroscopic and microscopic identifications. For molecular identification, a conventional technique was used in genomic DNA extraction of filamentous fungi due to their thick cell wall and presence of surface proteins protecting the fungus. These characteristics make it difficult to harvest the genomic DNA. Polymerase chain reaction (PCR) was carried out using internal transcribed spacer primers; ITS1 (forward) and ITS4 (reverse). The morphological identification and molecular technique showed that majority of these isolated fungi are Aspergillus sp.
Non antimicrobial touch surface materials such as stainless steel can act as a medium for transmitting microbes, leading to the increase of hospital-acquired infections and antibiotic-resistant microbes. Copper can be used to replace the current non-antimicrobial touch surfaces, however, the high cost of solid copper hampers copper from being the ideal choice. Therefore, stainless steel touch surfaces coated with copper can become the option for a low cost yet effective alternative. In this study, electrodeposition technique was used to coat copper on 304 stainless steel surface using 0.01 M CuSO4 solution, at pH 1. The electrodeposition process was done using chronoamperometry by applying -0.25 V vs. Ag/AgCl for 15 min. Morphological observation revealed that 304 stainless steel surface was uniformly coated with compact and dense copper. EDAX analysis showed the composition of copper of 98.9 wt. %, ranging in diameter from 60-90 nm grain size. Thickness of the coating was approximately 105.8 nm. The antibacterial property of copper coating was analysed by both Gram negative E. coli and Gram positive S. aureus. Results indicated that copper coating has excellent antibacterial behaviour in destroying both bacteria. E. coli was more sensitive to the biocidal action of the copper coating of which 100 % reduction was observed within 5 min of exposure. As for S. aureus, a 100% reduction was achieved only after 10 min of exposure.
This animal modelling study aimed to investigate the effects of LDR exposure on cellular ROS production, oxidative DNA damage, and alteration of cellular ultrastructure and apoptosis-related protein expressions. Ten male ICR mice were randomly divided into two groups consisting of control (Cx) and radiation (Rx) groups. On day 29 of post-acclimatisation, mice underwent total body irradiation with 100 µGy X-ray. Liver and lung tissues were assessed for the levels of cellular ROS production and Apurinic/Apyrimidinic sites generation. Ultrastructural alteration was detected using TEM, alteration of p53, Bax, and Bcl-2 expressions was determined by western blotting. Results showed that exposure to LDR significantly increased the levels of cellular ROS and AP sites in mice. Ultrastructure of the nucleus in Rx showed nuclear blebbing and structural changes in morphology that indicate cell death. Meanwhile, p53, Bax, and Bcl-2 proteins increased in expressions and altered the balance of Bax/Bcl-2 ratio. These findings may postulate that LDR exposure may enhance oxidative DNA damage and alter expression of apoptosis-related proteins.
Bax, Bcl-2, Low Dose radiation (LDR), oxidative DNA damage, p53
Bio-electricity generation by Microbial Fuel Cell (MFC) has gained considerable attention due to its integration with wastewater treatment such as Palm Oil Mill Effluent (POME). Investigation into pH effect and determination of optimal pH value ranges growth for acidogenic, acetogenic and methanogenic by natural mixed culture electroactive bacteria (exoelectrogens) growth in original non-Deoxygenated Mixed POME (nDMP) and Deoxygenated Mixed POME (DMP) in MFC was carried out. Current generation, power generation and maximum power were also monitored. Experimental results show that exoelectrogens in nDMP with pH 6.8 yielded the highest current generation of 61.51 mAm-2 and maximum power of 17.63 mWm-2. Overall, nDMP substrates with 3 pH ranges (5.5, 6.8 and 8.0) showed equal potential to generate power that is higher than DMP substrates. Comparison carried out for inter DMP substrates demonstrated that DMP with pH 6.8 and DMP with pH 8.0 showed equal potential to generate power, but not for DMP with pH 5.5. Subsequently, nDMP with pH 6.8 and nDMP with pH 8.0 showed equal potential for higher maximum power compared to nDMP with pH 5.5 and DMP substrates. This finding indicates that mixed microbial communities in DMP substrate are dominant with obligate anaerobic exoelectrogens bacteria which have less capability to generate electricity compared to nDMP substrate that was dominated by the aerotolerant and/or facultative anaerobic exoelectrogens bacteria.
Numerous studies of polylactide nanocomposites have been conducted. However, the role and importance of processing conditions is the subject of very few papers. In this work, polylactide and a constant amount (2 %w/w) of organoclayCloisite® 30B via melt intercalation technique were produced. It is generally believed that maximum benefits are achieved when organoclay is well dispersed in PLA matrix. It might be anticipated that melt processing conditions would have an important influence on the nanocomposites formed. Experimental design was carried out based on Box-Behnken methods, a response surface methodology (RSM) well suited to the goal of process optimisation. Three levels of processing temperature, rotor speed and mixing time were chosen in this study. The response was Young's modulus. The interaction effects with the most influence on the Young's modulus of these PLA/organoclay nanocomposites are temperature and speed. The maximum Young's modulus was predicted to be 1211 MPa at a temperature, speed, and time of 175°C, 100 rpm, and 7 min, respectively. Understanding the influence of processing conditions on the mechanical properties is needed for improving nanocomposites properties. Mathematical model and optimisations plot were used to illustrate the relationship between the parameters and mechanical properties considered. Results of the data analysis using Minitab software are presented.
In this work, the removal of Methyl Orange (MO) from aqueous solution was studied using a new non-conventional and eco-friendly adsorbent, spent tea leaves (STL). Untreated and acid treated STL were used as bio-adsorbent for removal of MO using batch method. Effects of different STL dosages (1 - 4 g), pH solutions (2–11) and initial dye concentrations (10 - 60 mg/L) were investigated. Adsorption experiments conducted using acid treated STL resulted in higher MO removal efficiency ranging from 79 to 92% for 1-4 g of adsorbent dosage compared to the untreated ones which resulted in only 18 to 56% of removal for the similar amount of dosage. In addition, acidic condition favours the MO removal as compared to alkaline medium. Experimental data were analysed using the Langmuir and Freundlich models of adsorption and it was found that adsorption isotherm was best described by Freundlich model and pseudo-first order equation with high correlation coefficient. Results revealed that acid treated STL, being a waste, has the greater potential to be used as adsorbent for MO removal from aqueous solution.
This paper reports a study of the formation of cellulose nanofibres from kenaf waste using chemical extraction method. The extracted holocellulose was then prepared for acid hydrolysis to form the cellulose. Before mixing it with polyvinyl chloride (PVA) solution and extruded using electrospinning under different parameters to produce PVA/kenafnanofibres. Results showed that the morphological structures of PVA/kenafnanofibres varied at different voltages. An increase in voltage from 10 kV to 20 kV produced more beads along the fibre length. In addition, the applied voltages were found to affect the resultant fibre diameter of the PVA/kenafnanofibres. The results also showed that the electrospinning parameters affect the shapes of the PVA/kenafnanofibre membranes. Based on the experimental works, the optimal applied voltage was found to be at 15 kV, where the resultant fibre diameter and membrane coverage area were approximately 43.9 ± 3.1 nm and 214.2 ± 15.8 cm², respectively.
This paper investigates the flexural properties of ArengaPinnatafibre reinforced epoxy composite (APREC) in relation to its fibre arrangement. The composites were produced using ArengaPinnatafibre as the reinforcement material and epoxy resin as the matrix. In this work, two types of ArengaPinnatafibre arrangement were under-studied, randomly distributed and unidirectional distributed (UD). Samples were prepared at 10vol%, 15vol%, 20vol%, and 25vol% of fibres reinforcement to matrix ratio for both types. Three-point bending configuration flexural tests were performed for both randomly distributed APREC and UD APREC at 10vol%, 15vol%, 20vol%, and 25vol% respectively. Results indicated that UD APREC have better flexure modulus and flexure strength for all the fibre loading percentages (vol%) as compared against the randomly distributed APREC. The 25vol% UD APREC showed the highest modulus (3.783 GPa) with an increment of 31.0% as compared against the pure epoxy (2.888 GPa). It was also observed that there was no significant increment on flexure strength for both random and unidirectional APREC as compared to pure epoxy (61.125 MPa), but the flexure strength value decreased for randomly distributed fibre orientation for all fibre volume percentages (vol%).
The incident of beach pollution in BatuFerringhi in year 2014 has created a major concern over water quality at the tourists' haven. In order to understand advection and dispersion of pollutants in the area, a coastal hydrodynamic model of Batu Ferringhi beach was developed in this study by taking into consideration its wind, tide, coastal current and riverine runoff. The model was calibrated and validated through observations from adjacent coastal monitoring stations. Simulation was then carried out to investigate scenario of the constituent water quality which originates from the three rivers in the vicinity. Results showed high concentrations of water quality parameters observed near the headland towards the northeast of the study area, with intermittent patchy escape which may retain more than one-third the initial concentrations, weighted by the river discharge. Even more worrying is that localised trapping of up to three-quarter the initial weighted concentrations also occurs at the beach, owing to the interactions between river flow and longshore current.
Advection/dispersion, BatuFerringhi, MIKE21, water quality
Chemical industries are greatly assisted by catalysts; and commonly used catalysts for C-C formation reactions are mainly phosphine-based complexes which are air and moisture sensitive. New air stable Schiff base Pd(II) complexes have been synthesised, characterised and screened for their catalytic potential. This paper reports three ONNO Schiff bases, namely, L2C [2,2'-((1E,1'E)-((2,2-dimethylpropane-1,3-diyl) bis (azanylylidene)) bis (methanylylidene)-) bis (4-chlorophenol)], L2M [2,2'-((1E,1'E)-((2,2-dimethylpropane-1,3-diyl)bis(azanylyli-dene)) bis (methanylylidene)) bis (4-methylphenol)] and L2H [2,2'-((1E,1'E) - ((2,2-dimethyl-propane-1,3-diyl) bis (azanylylidene)) bis (methanylylidene)) diphenol]. These were synthesised from 2,2-dimethyl-1,3-propanediamine and salicylaldehyde derivatives with Cl, CH3 and H at the meta position, respectively. The compounds were reacted with palladium(II) acetate yielding three palladium(II) complexes denoted as PdL2C, PdL2M and PdL2H. The structures of all compounds were elucidated through elemental analysis, 1H and 13C NMR, FTIR and melting point. The complexes were screened for catalytic activities in Sonogashira coupling reaction between iodobenzene and phenylacetylene in DMSO. PdL2H was found to be the most active catalyst with 87% iodobenzene conversion after 12 hours of reaction.
A new series of N,O-bidentate ligands, L1, L2, L3 and L4, and their Pd(II) complexes, PdL1, PdL2, PdL3 and PdL4 have been synthesised and characterised using various physico-chemical techniques, namely elemental analyses, IR and 1H and 13C NMR spectroscopies, and conductivity analysis. The molecular geometries of PdL2 and PdL4 have been elucidated through single crystal X-ray crystallography revealing 2:1 molar equivalence of ligand: Pd with the Schiff bases that exhibited bidentate ligands behaviour, in which they coordinated through the phenolic O donor atoms and imine N. Upon complexation, the ?(C=N) around 1629-1639 cm-1 and ?(C-O) around 1251 to 1252 cm-1 shifted to lower frequencies by 4 to 23 cm-1. In this study, three parameters were chosen for the reaction conditions optimisation, which were types of bases, loadings for the catalyst, and temperatures of the reaction. Pd(II) complexes exhibited good catalytic activities for Heck coupling reaction with 100% conversion at 100°C within 12 hours of reaction time. Reducing the reaction temperature to 80°C reduced the conversion to a maximum of 80%.
In IEEE 802.11 standard, Mobile Station (MS) such as laptop and smartphone are connected to Access Point (AP) to have a wireless connection. However, setting up AP to cover the whole area is costly and complicated. Limitation in signal capacity causes out-of-coverage area, where the MS cannot connect to the AP. In this paper, a portable wireless range extender (PWRE) is developed to assist MS that is located out of coverage area, or at the cell edge area connected to the internet. Development of PWRE involves two processes, which are connecting to existing wireless LAN (WLAN) network, and broadcasting a new WLAN network. The paper discusses development process of PWRE and analysis of its performance. PWRE was developed using a low power consumption microprocessor, known as Raspberry Pi. Performance of the developed PWRE is evaluated by comparing signal strength received by an MS located in the cell edge from an AP using two scenarios; with and without the PWRE. Results showed that the MS signal strength improved significantly with the deployment of PWRE. Other advantages offered by PWRE include being portable and energy efficient as it uses only 5V of power to operate.
Access Point, IEEE 802.11, portable, Raspberry Pi, wireless range extender, WLAN
One of the issues found in small and medium industry is the poor layout design affecting its productivity and line efficiency. In automotive industries, more attention should be given in improving assembly line to increase productivity. This paper presents application of line balancing at the accelerator and brake pedal assembly line at a small and medium automotive industry. Research methodology employed in this study includes time study, visualising cycle time based on Yamazumi Chart, distribution of workload on each workstation using line balancing based on the current takt time and re-layouting the assembly line. All the proposed layouts are assessed using commercially available software, DELMIA Quest to evaluate the robustness based on parameters such as fluctuation in demand, availability of the machine, and operator capacity. Finally, the outputs presented include reduction in manpower, maximum utilisation of manpower, as well as machine and minimum total production cost. This will lead to productivity improvement of the assembly line.
Automotive industry, line balancing, production efficiency
Teenage pregnancy is associated with maternal and neonatal morbidity. Some postulate that it is due to biological immaturity, while others postulate that it is due to inadequate antenatal care. The objective of this study is to compare the maternal and neonatal outcome between married and unmarried teenage mothers. A retrospective study was conducted from 2009 to 2012, where mothers aged below 20 year old were included. Maternal and neonatal outcome was assessed. A total of 750 patients aged below 20 year old delivered at Hospital Ampang. The trend of teenage pregnancy decreased from 3.1% in 2009 to 2.2% in 2012. A total of 578 (77.1%) mothers were married, while 172 (22.9%) were unmarried. Being unmarried was significantly associated with unbooked (p<0.001), preterm birth (p= 0.00468), and lower birth weight (p< 0.0001, and unpaired T-Test with 95% CI -0.2607 to -0.0933). However there is no significant difference in the number of mothers with hypertensive disease (p= 0.88428), diabetes in pregnancy (p= 0.39602), mode of delivery (p= 0.055 vaginal delivery, p = 0.4419 caesarean section, and p= 0.9097 instrumental deliveries) and NICU admission (p= 0.3779) between the two groups. Unmarried teenage pregnancy is associated with a lack of antenatal care, preterm birth, and lower birth weight compared to their married counterpart.
Ocean offers an inexhaustible source of water which is not consumable by humans due to its high salinity. Large amounts of energy are required for desalination, and producing it from fossil fuels can cause harm to the environment. As such, solar energy can be used as an alternative energy source to provide cheap consumable water. This paper aims to investigate the effects of design parameters on single slope solar still evaporation rate under Malaysian conditions. Single sloped solar stills, with varying evaporator basin thickness and condenser plate thickness at different separator heights, were fabricated and tested. The 0.5 mm evaporator basin thickness still set has the highest evaporated volume (250 ml), with evaporation percentage of 25%, while the set with a 1 mm evaporator basin thickness has the lowest evaporation percentage (5.65%) with 56.5 ml evaporated volume. Experimental results indicate that the single slope solar still evaporation rate is very much influenced by climate parameters, namely solar intensity and ambient temperature.
Desalination, evaporation rate, solar energy, solar stills
This study aimed to examine the association between second-hand smoke (SHS) exposure and psychological distress amongst non-smoking pregnant women. A cross-sectional study was used to obtain a representative sample of non-smoking pregnant women attending health clinics (n = 661) across six states in Malaysia. The duration of SHS exposure inside and outside the house was recorded from the participants. Psychological distress was assessed via General Health Questionnaire (GHQ-12). The analyses were conducted using a logistic regression adjusted for demographic variables and other variables. Amongst non-smoking pregnant women, the prevalence of global SHS exposure and psychological distress was 80.4% and 64.2%, respectively. In the multivariate adjusted odds ratio (OR) models for psychological distress and the duration of SHS exposures, there was an OR of 1.04 (95% CI: 0.61-1.77) for individuals with SHS exposure of 1-4 hours/week, 0.44 (95% CI: 0.23-0.81) for SHS exposure of 5-14 hours/week and 0.84 (95% CI: 0.32-2.22) for exposures of >15 hours/week compared to those with no SHS exposure outside the home. Meanwhile, SHS exposure outside the house with the duration of 5-14 hours might have temporary calming effects against psychological distress. Nonetheless, more research is needed to ascertain this.
Second hand smoker, psychological distress, pregnancy
Tobacco use is one of the largest causes of preventable diseases across the world. It is interesting to note that second-hand smoke exposure is a major public health problem in Malaysia. The objectives of this study are first, to explore the perspectives of pregnant mothers whose partners are smokers, and second, to explore barriers and facilitators to creating a smoke-free environment in their home. This study uses a qualitative method in analysing the experiences of 15 pregnant mothers taken from a specialist healthcare centre in Sungai Buloh, Malaysia. It discusses the perspectives of these pregnant mothers towards their partners' smoking habits, as well as the barriers and facilitators in creating a smoke-free home. From the interviews, it became apparent that pregnant mothers despised their partners' smoking habits due to smoke odour, lack of money, and poor health. The barriers in creating a smoke-free home include the attitude of the smoking spouse, difficulty in weaning off the habit, excessive encouragement by a spouse, difficultly in advising a smoking spouse, influences from friends, and wrong perceptions. Meanwhile, the facilitators towards creating a smoke-free home are illnesses developed through smoking, multiple reminders from family members, and nicotine replacement therapy (NRT) were perceived to work on certain smokers and habitual cues in quitting smoking. The transition process towards making homes smoke-free is complex and individualistic; healthcare professionals may need to tailor strategies to take into account the specific contexts of each individual. More education programmes on the impacts of smoking and second-hand smoke exposures to family members and smoking cessation are needed for both pregnant mothers and their smoking partners.
In this work, sensors were prepared by depositing the pH sensitive indicator (bromothymol blue) entrapped in polyaniline sol-gel onto the un-cladded middle potion of optical fiber. Polyaniline is sensitive to pH. However, it is important to study ways to increase sensitivity of the indicator by improving a combination of the materials used and pH sensor fabrication method. The fabrication and characterisation of optical fiber pH sensor on absorption intensity in arbitrary unit (a.u) were evaluated and optimised. The better sensitivity of the optical pH sensor was used to identify the optimum setting for number of layers deposited, coated length, and withdrawal rate. Thickness of the membrane film depends on the number of deposited layers and withdrawal speed which mainly affects sensitivity. The sensitivity of the optical pH sensor represents the slope (a.u/pH) of the absorbance intensities in pH 4, 5, 7, 9 and 10. Results obtained herein suggest that the optimised setting for bromothymol blue sol-gel coated optical fiber with thickness of 285.4 nm is 4 deposited layers, 20mm/s withdrawal rate and 0.5 cm coated length.
The aim of this paper is to interrogate the principle of heat gain by the Overall Thermal Transfer Value (OTTV) through residential building facades. This study proposes three façade configurations as case studies to determine their capability of achieving the OTTV set by the current residential standards. Utilising the OTTV formula provided by the Malaysian Standards, the OTTV of each case study was calculated using parameters including Window-to-Wall Ratio (WWR), Shading Coefficient (SC), U-values and solar absorption (a). Results showed that each of the façade generated OTTV exceeding the regulation of 50 Wm-2. The study uncovered the increase in WWR leading to the increase in OTTV. The OTTV increased alongside window areas due primarily to the high amount of heat gained through windows, a constituent component of OTTV. Simultaneously, high Shading Coefficient (SC) and U-values were found to cause the high amount of solar heat gained through windows. The result underpins the impacts of high solar heat gain particularly from windows of a building envelope on OTTV. Recommendations for improvement of OTTV of the residential façades are also discussed.
Apartment facades, Green Building Index (GBI), modern style, OTTV
Bismuth oxide nanoparticles (Bi2O3 NPs) have gained a spot in the development of novel molecular probes for in vivo biomedical imaging. It exists in six polymorphic forms and each of them exerts with different stabilities according to its synthetisation temperature. The aim of this preliminary study is to determine effect of different synthetiation temperatures on cellular viability in vitro. One hundred µg/ml Bi2O3 NPs synthesised at 60, 90 and 120°C were characterised using scanning electron microscope (SEM) and their cytotoxicity was evaluated using cell viability assay (MTT assay) upon 24 hours exposure to Chang liver cells. Images captured by SEM showed an average diameter of 300 nm monoclinic-shaped with high crystalline formation of all three Bi2O3 NPs. MTT assay revealed increase in liver cell viability as the synthetisation temperature of Bi2O3 NPs increase. The outcomes suggested that synthetisation temperature of Bi2O3 NPs plays a role in cellular viability, hence predictive to the biocompatibility of these nanoparticles to be applied as in vivo radiographic contrast medium.
Bismuth oxide nanoparticles (Bi2O3 NPs), cell viability, cytotoxicity, synthetisation temperature
Personality represents the mixture of features and qualities that built an individual's distinctive characters including thinking, feeling and behaving. Traditionally, self-assessment method via questionnaire is the most common means to identify personality. Since recommender systems and advertisement campaigns have evolved rapidly, personality computing has become a popular research field to provide personalisation to users. Currently, researchers have utilised social media data for automatically predicting personality. However, it is complex to mine the social media data as they are noisy, free-format, and of varying length and multimedia. This paper proposes a decision tree C4.5 algorithm to automatically predict personality based on Big Five model. The Big Five Inventory and ZeroR algorithm were included to be served as the baseline for performance evaluation. Experimental evaluation demonstrated that C4.5 performs better than ZeroR in terms of accuracy.
Big Five, decision tree, personality, social media
Applying an intelligent system means the machine is capable of making its own unique decision. Fuzzy logic is a form of logic that acknowledges other forms of true and false values. With fuzzy logic, propositions may be diagrammatic with degrees of truthfulness and falsehood. The main aims of this study are to demonstrate the method to apply fuzzy logic in a structure that uses Arduino as its brain, and apply it in a line follower mobile robot's decision making algorithm. This mobile robot consists of two front wheels and a nub caster at the back. It uses a line follower array that consists of eight infrared (IR) sensors. The system control is based on the input from IR sensors, which measures the intensity of light reflected by the track. Data were then transmitted to the microcontroller and will then be sent the correct command to the motor driver so that the trail can be followed. The performance of the line follower robot when using the fuzzy logic algorithm was compared to the line follower algorithm, which uses simple if-else commands. Analysis is primarily on the time taken to complete the track, along with the behaviour of the robot while manoeuvring. From the results, fuzzy logic is shown to provide a better performance in terms of the time taken to complete the track compared to the other set of rules. In addition, from the video recordings, fuzzys are moving smoother as compared to the non-fuzzy logics.
Arduino, Fuzzy Inference System, fuzzy logic, line follower robot, Matlab
In this work, two types of controller were designed for the nonlinear air blower system PT326 used at the Instrumentation Laboratory Faculty Electrical Engineering, UiTM, Shah Alam. This work began with collection of data from the experimental work. Once the S-shape of the system response was obtained, the procedure of getting the process dead time, tD and time constant tC was applied to the S-shape form. By determining these two values, the optimum values of PI and PID controllers can be calculated. From the acquired data, the simulation model was developed in MATLAB/Simulink R2013a software using the transfer function obtained from the open-loop control system. The modelling system is based on the transfer function of open-loop air blower system PT326 before the design state of finding a suitable controller can be suggested. The controller design of PI and PID was obtained using the first method Ziegler-Nichols tuning rules. The result from the simulation shows that the Ziegler-Nichols first tuning rules can be applied in designing the PI and PID controller based on S-shape response obtained in open-loop test.
Air blower PT326, PI, PID, Ziegler-Nichols first method
Palm Oil Fuel Ash (POFA) is a biomass produced from palm oil industries. POFA is known to contain a high amount of silica and has been proven by XRF spectroscopy, in which the silicon dioxide content is 72.63%. In this study, silica was synthesised from POFA. To extract the silica, POFA was fused with alkaline agent (Na2CO3) before mixing with Cethyltrimetyl Ammonium Bromide (CTAB) and Sulphuric Acid (H2SO4). Sodium silicate solution from the fusion was used as silica precursor replacing conventionally used silica source, Tetraethoxilane (TEOS). XRD pattern showed that raw POFA dominantly consists of silica. Meanwhile, FTIR analysis of the synthesised silica exhibited spectra bands at 3393 cm-1, 1635 cm-1, 1028 cm-1 and 787 cm-1 that corresponded to the functional groups of Si-O and O-H. Thus, it could be concluded that silica was successfully extracted from POFA by the alkaline fusion method.
Pedestrian level in the urban area is an important area where most of pedestrians' activities occur at this level. Therefore, the purpose of this study is to investigate effects of various building layouts on mean wind speed ratio at the pedestrian level. The mean wind speed ratio at the pedestrian level was analysed in order to determine whether the building layouts configured within this research are able to enhance outdoor ventilation and ensure good pedestrian comfort level. The simulation model consists of two main areas which are the upstream area and downstream area with a setback distance, d. The building layouts at upstream area are arranged in staggered arrangements (ST) or square arrangements (SQ), while the downstream areas are in a fixed staggered arrangement (ST). Packing density in both areas is 25% with three setback distances which are 3H, 5H and 7H. Based on the results, the mean wind speed ratio at the pedestrian level in a downstream area with longer setback distance will provide a higher mean speed ratio, and the influence of upstream building arrangements on the mean wind speed ratio of the downstream area decreases as the setback distance increases. Hence, the mean wind speed ratio of downstream area depends on the setback distance between the upstream and downstream areas.
Self-similarity network traffic is considered as one of stochastic process studies in telecommunications engineering. In determining self-similarity traffic, Hurst value is an important parameter to be measured. This paper presents self-similarity traffic measurement using Rescaled Range, R/S statistical method in estimating Hurst parameter value. Inbound internet traffics on an IP-based campus network in Malaysia, which implements a 16.0 Mbps speed to internet and supports 10GE bandwidth at switch level, are captured and measured. The objectives of this research are to observe and present the existence level of Hurst parameter value, type of self-similarity and overall percentage of Hurts parameter estimation. The inbound traffic is measured due to its relevancy to next development on policing and shaping algorithm traffic model. Solarwinds Net Flow machine is setup on a campus gateway to its Wide Area Network (WAN). Data of the traffic like in flow, size and speed were taken over 20 days and 14 weeks in different inter-arrival time. These traffics are analysed, which lead to the impacts of packet loss, throughput and speed in network performance. Results present the Hurst parameter value, the existence of Long Range Dependant Self-similarity traffic distribution and percentage level of Hurst parameter value for the three types of captured traffic.
Analysis, Hurst Parameter Estimation, internet traffic, network performance, Self-similarity
Implementation of Trivial File Transfer Protocol (TFTP) in embedded system is significant because of the speed and simplicity. However, no security service in TFTP marks its major limitations. In this work, a pre-shared Diffie Hellman Key Exchange (DHKE) technique was proposed for mutual authentication to achieve the same secret key in TFTP communication protocol. We also integrated the system with feasible compression and encryption process to significantly improve the TFTP communication performance. The DHKE proof of concept is discussed briefly to show the feasibility of the pre-shared technique on the protocol. Also, the experiment was performed on constrained embedded devices to analyse the performance of compression/encryption scheme in TFTP. From the results obtained, the combined encryption and compression process is able to reduce the time by about 30% compared to the original file transmission time. Thus, the proposed work presents both advantages to reduce file size and provide security for the data. This is a preliminary work to provide a secure TFTP communication which has benefits to be implemented in embedded system field and IoT services.
This study was carried out to investigate effects of acoustic and thermofluid performance of a Ranque-Hilsch Vortex Tube (RHVT) with different numbers of swirl generator nozzles. The number of nozzle used in the experiment was 1, 2, 3, 4, 5 and 6 nozzle(s), respectively. Sound signal produced by the device was recorded using two microphones located at hot side and cold side of the tube. The sound signal was transformed using Fast-Fourier Transform (FFT) to obtain the frequency representation. Then, the frequencies produced were related to its themofluid performance of each configuration.
Fast-Fourier Transform, nozzle, RHVT, signature frequency
In dentistry, determining position and orientation parameters for each tooth mostly based on orthodontic qualitative perception. There is no quantitative method to obtain those parameters in three dimensional (3D) images, especially in some complicated cases. This study proposed a quantitative approach for locating centroid of tooth position and also its frame axes orientation. Based on Cone Beam Computed Tomography (CBCT) x-ray images, a 3D model of teeth was obtained to visualise dental features. A few dental features were used to calibrate the location of centroid and identify tooth reference axes, or frames. Two definitions of centroid and frame axes were proposed for single root and for multiple roots of teeth. Based on these two definitions, the positions and orientations of each tooth were determined and evaluated. Teeth positions and orientations were obtained with respect to a reference axis, which is the CBCT coordinate system. Having a quantitative method to obtain position and orientation of tooth, especially in 3D, will help dental rehabilitation in many ways.
This paper presents a study on node impersonation attack in Wireless Sensor Networks (WSN) environment. Node cloning is a major attack among sensor where the leak of node identity is easy to clone if it is not secured. For this purpose, an analysis that explores techniques to prevent node cloning attack was done using a unique node identity. An algorithm to generate the unique identity was developed on high performance ARM hardware and programmed the data authentication together with sensor nodes. Communication among the sensor nodes and base station depends on a successful authentication using the unique identity (UID). The sensor nodes are resistant against node cloning attack when the UID identity is unequal. Results present successful generation of the UID, while execution time between two nodes is faster and low power consumption is used on the technique. The analysis has proven that the unique UID is secured by the developed node identity algorithms and against cloning attack. This outcome is significant for new development of secured WSN sensor hardware, which can be implemented in new network technology.
In this paper, the wear properties of nano-filled Glass Fibre Reinforced Polymer (GFRP) composite are studied based on the effects of the architecture of the glass fibre and test environment. Wear tests were done under two different conditions; dry environment test and wet environment test. The dry and wet environment tests were conducted using the abrasion resistance tester (TR600) and slurry erosion tester, respectively; the slurry mixture of sand and water were used in the wet environment test. Two types of glass fibres architecture were understudied; unidirectional and woven. It was found that 3 wt.% filler content is the optimum amount to be used for the GFRP composite. Unidirectional nano-filled GFRP composites exhibited the lowest wear rates due to their closely aligned glass fibre arrangement. The unidirectional fibre alignment provided less empty spots for the interlocking process to take place, thus reducing the ploughing action of wearing. However, when tested in the wet environment, effects of other testing parameters such as the architecture of fibre and filler contents became less significant. The composites, which were tested in wet environment, showed the lowest wear rates compared to the ones tested in the dry environment. This is due to the presence of water that helps to wash away the pulverised glass fibre, thus reducing the friction and the three-body wear effect.