This paper presents a transmission line (TL) modelling which is based upon vector fitting algorithm
and RLC passive filter design. Frequency Response Analysis (FRA) is utilised for behaviour prediction and fault diagnosis. The utilities of the measured FRA data points need to be enhanced with suitable modelling category to facilitate the modelling and analysis process. This research proposes a new method for modelling the transmission line based on a rational approximation function which can be extracted through the Vector Fitting (VF) method, based on the frequency response measured data points. A set of steps needs to be implemented to achieve this by setting up an extracted partial fraction approximation, which results from a least square RMS error via VF. Active and passive filter design circuits are used to construct the model of the Transmission line. The RLC design representation was implemented for modelling the system physically while MATLAB Simulink was used to verify the results.
This article aims to quantify the colour discrimination ability by using Total error scores (TES) to categorise colour discrimination level into superior, average or inferior levels under three different types of light sources, with different spectral power distribution. Colour discrimination was investigated using Farnsworth-Munsell 100 hues and compared upon three light sources: compact fluorescent light (CFL), fluorescent light (FL) and light emitting diode (LED). Total error score calculated and pattern of colour caps misplacement plotted used the web-based scoring method (http://www.torok.info/colorvision/fm100. htm). Total error score (TES) for three types of light sources (TES for LED 58.00 ± 18.67, FL 80.00 ± 19.27 and CFL 127.25 ± 28.02) were significantly different [One-way ANOVA (F=9.98, P
The use of an artificial neural network (ANN) is becoming common due to its ability to analyse complex
nonlinear events. An ANN has a flexible, convenient and easy mathematical structure to identify the
nonlinear relationships between input and output data sets. This capability could efficiently be employed
for the different hydrological models such as rainfall-runoff models, which are inherently nonlinear in
nature and therefore, representing their physical characteristics is challenging. In this research, ANN
modelling is developed with the use of the MATLAB toolbox for predicting river stream flow coming
into the Ringlet reservoir in Cameron Highland, Malaysia. A back propagation algorithm is used to train
the ANN. The results indicate that the artificial neural network is a powerful tool in modelling rainfallrunoff.
The obtained results could help the water resource managers to operate the reservoir properly in
the case of extreme events such as flooding and drought.
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
This paper investigates the effect of acid and silane treatment of Carbon Nanotubes (CNT) on wear properties of epoxy polymer composite. The wear test done was based on ASTM D3389 standard using the Abrasive Wear Tester (TR 600). Characterisation analysis was also done using Transmission Electron Microscopy (TEM) in order to study the dispersion of the CNT inside the epoxy matrix. When untreated CNT was added to the epoxy with amounts of 0.5, 0.75 and 1.0 wt%, the wear rates did not improve except for 0.5 wt% CNT filled epoxy. This was due to the lack of dispersion which causes larger chunks of material being dug out, thus contributing to a higher mass loss and wear rate. When treated with acid and silane, 0.75 wt% and 1.0 wt% CNT filled epoxy composites showed improvement. The TEM images of 0.5 wt%, 0.75 wt% and 1.0 wt% PCNT filled epoxy supported the claim of the lack of dispersion of PCNT inside the epoxy.
This paper presents a study on the effect of Arenga Pinnata fibre volume fraction on the tensile and compressive properties of Arenga Pinnata fibre reinforced epoxy composite (APREC). The composites were produced using four different Arenga Pinnata fibre volume contents, which were 10vol%, 15vol%, 20vol%, and 25vol%, in unidirectional (UD) fibre alignment. Tensile and compression tests were performed on all APREC specimens in order to investigate the effect of fibre volume fraction on modulus of elasticity, strength and strain to failure. The morphological structure of fractured specimens was observed using scanning electron microscopy (SEM) in order to evaluate the fracture mechanisms involved when the specimens were subjected to tensile or compressive loading. The results indicated that the higher the amount of Arenga Pinnata fibres, the higher the stiffness of the composites. This is shown by the increment of tensile and compressive modulus of the specimens when the fibre volume content was increased. Tensile modulus increased up to 180% when 25vol% Arenga Pinnata fibre was used in APREC compared to Pure Epoxy specimen. It can also be observed that the tensile strength of the specimens increased 28% from 53.820 MPa (for Pure Epoxy) to 68.692 MPa (for Epoxy with 25vol% APREC addition). Meanwhile, compressive modulus and strength increased up to 3.24% and 9.17%, respectively. These results suggest that the addition of Arenga Pinnata fibres significantly improved the tensile and compressive properties of APREC.
Distributed generator is one of the most common sources of electric power as it has many advantages. However, it might cause negative effects to the distribution system if appropriate conditions are undermined. Thus, this paper describes ways to optimise the use of distributed generator in a distribution system in order to reduce total power losses and to improve system performance by increasing stability of the voltage profile. This study focuses on the installation of distributed generator that is installed on 69-bus radial distribution system. Optimisation are done through Particle Swarm Optimization and Voltage Stability Indicator. The findings show that total power loss was reduced by 44.6%, and there was improvement in voltage profile stability.
Pressure relief system is a system to prevent overpressure inside protected equipment that exceeds its maximum allowable working pressure (MAWP) to disposal treatment. Relief system is designed on two different plant case studies, which are dimethyl-ether and ethylbenzene plants by using conventional design procedure. Nevertheless, the conventional design steps are not considering cost optimization of plant installed with relief system. Thus, the design pressure of protected equipment, piping diameter, and disposal treatment is set to be manipulated variables to determine the cost minimization. Pressure drops of inlet piping and backpressure are as constraint variables due to standard requirements. The standards state that inlet piping pressure drops should be below 3% of set pressure and outlet piping pressure drop to set pressure percentage based on range to determined types of the relief valve to be used. From that, optimum plant design with consideration of pressure relief system’s installation can be achieved by calculating the total cost of plant designed with relief system when set pressures are changed. As a result, dimethyl-ether plant shows a minimum point of the total cost at 170% of set pressure increment, which is lower than its original design. On the other hand, ethylbenzene plant gives optimum point at original design as the total cost is higher at set pressure increment.
In this paper, we present the absolute stability of the existing 2-point implicit block multistep step methods of step number k = 3 and k = 5 and solving special second order ordinary differential equations (ODEs). The methods are then trigonometrically fitted so that they are suitable for solving highly oscillatory problems arising from the special second order ODEs. Their explicit counterparts are also trigonometrically fitted so that in the implementation the methods can act as a predictor-corrector pairs. The numerical results based on the integration over a large interval are given to show the performance of the proposed methods. From the numerical results we can conclude that the new trigonometrically-fitted methods are superior in terms of accuracy and execution time, compared to the existing methods in the scientific literature when used for solving problems which are oscillatory in nature.
The volume of waste generated from surface coating industries is of global concern. The disposal of this waste in the form of effluent has put enormous pressure on land and also poses as a health hazard when it leaches into soil and underground water. The study aims to examine the utilization of vinyl acetate effluents from water based paint factories as an admixture in concrete. Concrete specimens containing 0%, 2.5%, 5% and 10% of vinyl acetate effluents by weight of cement were prepared. The specimens were tested for drying shrinkage for 28 days and porosity was tested using mercury intrusion porosimetry. Findings show that concrete containing various proportions of vinyl acetate effluents manifests higher shrinkage behaviour compared to the control item. An investigation of pore size distribution reveals that polymer effluents have particles size larger than 50 nm which are categorize as macroporous in accordance to IUPAC classification. It can be concluded that adding polymer vinyl acetate effluents affects concrete deformation due to the condition of its pore structures. The utilization of this material may provide beneficial effect in terms of the durability performance of concrete and minimize environmental pollution.
The assessment of model fit is important in Structural Equation Modeling (SEM). Several goodness-of-fit (GoF) measures are affected by sample size and the number of parameters to be estimated. A large sample size is needed to test a complex model involving a large number of parameters to be estimated. One of the solutions to reduce the number of parameters to be estimated in a given model is by considering item parceling. The effects of item parceling on parameter estimates and GoF measures in a structural equation model was investigated via a simulation study. The simulation results indicate that the parameter estimates are closer to the true parameter values for the IL model whenever the distribution of data is normal but biased when the data is highly skewed. The parameter estimates for the IP model were found to be underestimated for both normal and non-normal data. The GoF measures were higher for the IP model. Additionally, the RMSEA was lower for the IP model when data were skewed. This shows that item parceling may improve GoF measures but the effect of exogenous on endogenous variable is underestimated. Application to a real data set confirmed the results of the simulation study.
A Structural Equation Model (SEM) is often used to test whether a hypothesised theoretical model agrees with data by examining the model fit. This study investigates the effect of sample size and distribution of data (normal and non-normal) on goodness of fit measures in structural equation model. Simulation results confirm that the GoF measures are affected by sample size, whereas they are quite robust when data are not normal. Absolute measures (GFI, AGFI, RMSEA) are more affected by sample size while incremental fit measures such as TLI and CFI are less affected by sample size and non-normality.
This study was performed to evaluate the antifungal activities of methanolic fractions from the stem bark of Entada spiralis Ridl. against human dermatophytes and yeast-like fungus in vitro. Three types of human dermatophyte, Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102 and Trichophyton tonsurans ATCC 28942, and one yeast-like fungus, Candida glabrata ATCC 66032, were tested against the methanolic fractions labelled FA1, FA4 and FA5. T. mentagrophytes, T. tonsuran and M. gypseum were susceptible to all tested fractions in a concentration-dependent manner whereas C. glabrata was resistant. Fraction FA1 at a concentration of 400 mg/mL was found to exhibit the highest antifungal activity with the inhibition zone diameter of 22 mm (T. mentagrophytes). This fraction showed a minimum inhibitory concentration MIC of 0.097 mg/mL while the MIC value for the fraction FA4 and fraction FA5 was 3.12 mg/ml and 1.56 mg/ml respectively. Agar overlay bioautography assay results showed that most of the bioactive compounds were found in the fraction FA1. Based on these findings, it can be concluded that the stem bark extracts of E. spiralis can be a future source of potent natural antimicrobial drugs for superficial skin diseases.
Planar electromagnetic sensors are widely used in many applications due to its low cost, simple
architecture, and fast response. Currently, there are many types of membranes which have been introduced
to remove contaminants from an aqueous solution. Hence, the water quality could be maintained and
safe to consume. The objective of this paper is to apply and investigate the effectiveness of a selective
membrane in detecting nitrate, phosphate, zinc, and nickel ions by means of planar electromagnetic
sensors array (PESA). The samples have four different concentration levels, 5 ppm, 25 ppm, 75 ppm,
and 100 ppm. The selective membrane’s performance is evaluated based on absolute average sensitivity
(|Z%|). This performance is compared with conventional coating such as incralac. The developed
membrane consists of two elements which are polymer and solvent. Modified silica is selected as a
polymer material while N-(2-Aminoethyl)-3 Aminipropyltrimethoxysilane is selected as a solvent. The
selection of these materials is based on their ability to attract the contaminants in the aqueous solution
and hence increased the selectivity. The proposed sensor with a membrane shows its higher sensitivity
compared to incralac. The highest sensitivity is 338 % which observed in the presence of membrane
for the nickel detection. Meanwhile, the lowest sensitivity using membrane is 12 % for zinc detection.
Electron beam irradiation, without any addition of cross-linking agents, was investigated at varying
doses of EB-Irradiation to develop an environmentally friendly hybridized kenaf (bast)/ pineapple leaf
fibre (PALF) bio-composites. Improvement in tensile property of the hybrid was achieved with the result
showing a direct proportionality relationship between tensile properties and increasing radiation dose.
Statistical analysis software (SAS) was employed to validate the result. HDPE has been shown to have
self-cross-linked, enabling interesting tensile properties with irradiation. Statistical analysis validated
the results obtained and also showed that adequate mixing of fibres and matrix had taken place at 95%
confidence level. Hybridization and subsequent irradiation increased the tensile strength and modulus
of HDPE up to 31 and 185%, respectively, at about 100kGy. Meanwhile, SEM was used to view the
interaction between the fibres and matrix.
Two different supercapacitor configurations were fabricated using coconut shell-based activated
carbon. Results for cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge measurements are presented and discussed for both configurations. The results show that coconut shell-based activated carbon is viable economical alternative electrode material to expensive activated carbon (AC) and carbon nano tubes (CNT). Meanwhile, the calculations from the charge-discharge characteristics show that the disk-shape supercapacitor, with 10% polyvinylidene fluoride binder (PVdF), has the highest specific capacitance (70F/g). Thus, the testing shows that the flat-laminated super-capacitor with 10% binder (PVdF) has the lowest (10.1ohms). Sources of high equivalent series resistance (ESR) are proposed and methods of reducing it are also discussed in this paper.
The study aimed at using satellite remote sensing in identifying the land-use changes that have occurred in Lafia, Nigeria within the past 35 years, especially in relation to the current and the predicted future invasion of a fern (Pneumatopteris afra). Landsat satellite images OLI/TIRS, ETM+ and TM within the interval of 15 years from 1985 to 2020 were used for the extraction of land-use. Six broad classification systems were used to classify the land-use changes by employing a supervised classification technique. In 1985, the bare land dominated the land-use having an area of 69156 ha while the wetland was the least having an area of 3412 ha. However, in 2020, the built-up area has dominated the land-use of Lafia with an area of 144645 ha (52.21%) while the wetland still remained the least with area of 1477 ha. This is obviously due to the geometric increase in the urbanization of this city. There was a consistent loss of the forests from 1985 to 2020 with an annual rate of loss of 0.46%. This resulted in a loss of 44329 ha of forests in 2020 out of the 47643 ha in 1985. This approximately leads to a total loss of 172,732,045 USD of forest products. The current invasion of Pneumatopteris afra in Lafia was found to fall within the shrub and grasses land-use class. This indicates that the landsat satellite could not detect the wetlands where the plant dominated due to its massive covering. This study calls for immediate conservation of the remaining forests and wetlands in Lafia to prevent further encroachments and invasion by plants.
iPS cells were originally generated using monocistronic retroviral vectors carrying the Yamanaka factors ‘OSKM’. The development of a polycistronic viral vector with OSKM linked by 2A peptides has simplified reprogramming procedure and reduced the risk of multiple proviral integrations and insertional mutagenesis. In this study, we demonstrated the production of the polycistronic lentiviral vector encoding OSKM in a single cassette without a reporter gene or drug-based selection system. Syncytia formations were clearly seen following the co-transfection of a lentiviral plasmid construct with the structural and packaging plasmids. The virion was collected at 48 hours post-transfection. Afterwards, the viral titers were measured by the expression of Sox2 protein from transduced HT1080 cells. Subsequently, Oct4 expression was successfully detected in mouse fibroblasts in the range of 5, 10 and 20 MOIs with expression of 90.7%, 97.5% and 98%, respectively. The results obtained from this study could be used as a model for the production of OSKM lentiviral vector for newcomers to cellular reprogramming research.
The objectives of this study were firstly, to develop a simulation model (SM) for a single reservoir to identify the standard operating policy (SOP) of a reservoir based on a monthly operating period, and secondly, to evaluate the performance of the proposed Makhoul reservoir using a Developed Simulation Model (DSM) in reducing flood risk. This reservoir is located on the River Tigris, approximately 180 km upstream of Baghdad, Iraq. The performance of the reservoir in reducing flood risk was evaluated using two designs and records of flood waves gathered over two years. The first design was the present one, while the second was developed by increasing the operational storage to its maximum, based on the digital maps of the region. The flows downstream of the reservoir were compared, with and without the reservoir in the two years in question. Four parameters resulting from the two designs were compared: storage, surface area, elevation and power. The results suggested that the reservoir would be ineffective in reducing flood risk, but it would have the ability to provide hydroelectric power using the two designs, with the new one showing better ability at doing this. The reservoir can also serve purposes such as irrigation, fish wealth development and recreation. This DSM proved its effectiveness in evaluating the performance of the single storage system used for reservoirs.
Recently, license plate detection has been used in many applications especially in transportation systems. Many methods have been proposed in order to detect license plates, but most of them work under restricted conditions such as fixed illumination, stationary background, and high resolution images. License plate detection plays an important role in car license plate recognition systems because it affects the accuracy and processing time of the system. This work aims to build a Car License Plate Detection (CLPD) system at a lower cost of its hardware devices and with less complexity of algorithms’ design, and then compare its performance with the local CAR Plate Extraction Technology (CARPET). As Malaysian plates have special design and they differ from other international plates, this work tries to compare two likely-design methods. The images are taken using a web camera for both the systems. One of the most important contributions in this paper is that the proposed CLPD method uses Vertical Edge Detection Algorithm (VEDA) to extract the vertical edges of plates. The proposed CLPD method can work to detect the region of car license plates. The method shows the total time of processing one 352x288 image is 47.7 ms, and it meets the requirement of real time processing. Under the experiment datasets, which were taken from real scenes, 579 out of 643 images were successfully detected. Meanwhile, the average accuracy of locating car license plate was 90%. In this work, a comparison between CARPET and the proposed CLPD method for the same tested images was done in terms of detection rate and efficiency. The results indicated that the detection rate was 92% and 84% for the CLPD method and CARPET, respectively. The results also showed that the CLPD method could work using dark images to detect license plates, whereas CARPET had failed to do so.