Universiti Putra Malaysia
Download Latest Complete Journal - JST Vol. 27 (3) Jul. 2019
Foreword by the Chief Executive Editor
No.ArticlesDownloads
1
Full Article
(Downloads: 16)
Abstract (Viewed: 3)Mining is one of the anthropogenic activities that can negatively affect the environment especially the waterways. Discharges from mining activities are usually in acidic state and containing elevated concentrations of metals. The exposure to these contaminants may cause several harmful effects not only to aquatic organisms but also to human health. The Whole Effluent Toxicity (WET) test was applied to evaluate the toxic effects of tin mining effluents to aquatic organisms. An acute toxicity test with zebrafish (Danio rerio) was conducted where fish was exposed to 3.13%, 6.25%, 12.5%, 25% and 50% effluent for 96 hours under static renewal test system. Effects of effluent exposure were determined using endpoints with mortality of median lethal concentration (LC50) value. Results indicated that the LC50 value of zebrafish when exposed, was 14.21% effluent. The physicochemical properties of the effluent were also evaluated in order to assess the cause-effect relationships of the effluent. The low pH values of the mine effluent might be the main reason contributing to the fish mortality. This approach provides additional information of tin mining effect on freshwater fishes as well as to human health.Acute toxicity, LC50, tin mining effluent, whole effluent toxicity (WET), zebrafish
2
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(Downloads: 10)
Abstract (Viewed: 3)Oil spill introduces hydrocarbons into the marine environment and forms oil slicks, which aggregate with other debris to form tarballs. Tarballs are composed of toxic hydrocarbons, which persist in the environment, causing economic and ecological damages. This work studied the isolation and optimization of diesel-oil biodegradation by an indigenous bacterium, identified by 16S rRNA gene sequence analysis, in tarball. An experimental methodology using a Taguchi orthogonal array was applied to optimize the effects of diesel concentration, salinity, nitrate concentration, pH, temperature, agitation speed and time. An isolated bacterium identified as Cellulosimicrobium cellulans removed 88.4% of diesel oil under optimized conditions, where initial diesel-oil concentration was 5% (v/v), NaCl concentration was 20 gL-1 and NH4NO3 concentration was 2 gL-1 in Minimal Salt Media at pH 7, 40°C and 100 revolutions per minute for 5 days. Tarballs harbor hydrocarbon-degrading C. cellulans that can be used under optimized conditions to design an effective oil spill bioremediation technique for mitigating oil pollution.Biodegradation, Cellulosimicrobium cellulans, diesel-oil, hydrocarbon, Taguchi
3
Full Article
(Downloads: 19)
Abstract (Viewed: 13)Diuron has been substantially used in different parts of the world as an herbicide and as a bioactive ingredient in antifouling paint. However, knowledge on the toxicity of Diuron that could adversely affect non-targeted aquatic organisms, especially fish; is still deficient. Therefore, this study was conducted to determine the possible sublethal effects of phenyl-urea herbicide Diuron at the cellular level of the liver and kidneys of an adult Javanese medaka (Oryzias javanicus), which has been used as the novel model organism. In the present study, histological assessment was carried out using the hematoxylin and eosin (H&E) staining protocol where the samples were preserved in 10% buffered formalin and sectioned into 5 µm thickness. The 210 samples used contained a range of Diuron concentrations comprising 1 µg/L, 50µg/L, 100 µg/L, 500 µg/L and 1000 µg/L; which also included the control treatments. Semi quantitative analysis revealed that liver and kidney tissues exposed at higher concentrations (500 µg/L and 1000 µg/L) showed significantly moderate to severe deformities and mild lesion alterations were already shown even at a lower concentration of Diuron exposure (1.0 µg/L), as compared to the control treatment of dechlorinated water (p<0.05). The most evident and observable severity of the lesions in the liver were due to vacuolation, congestion and nodule necrosis while the kidney showed tubule degeneration, glomerulus shrinkage and hemosiderin. Hence, this study further reinforces the documentary evidence in developing O. javanicus as the novel model organism to represent tropical regions in aquatic toxicological studies. Although the level of Diuron in Malaysia is unthreatening, this emerging hazardous chemical can seriously affect the aquatic ecosystem in later years.Diuron, histology, Javanese medaka, kidney, liver, sublethal
4
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(Downloads: 5)
Abstract (Viewed: 1)Greywater traditionally receives the least attention compared to other aspects of environmental sanitation. In Malaysia, most of village houses discharged lots of significant portion of greywater into stream without any treatment. Laundry Greywater (LGW) is one of the largest portion of greywater that has been directly discharged to the stream. The aim of this study was to identify the physical and chemical characteristic of laundry greywater quality from the houses and also to evaluate the efficiency of using ceramic waste coarse aggregate filtration for LGW treatment. The effectiveness of the treatment systems was optimized with different Hydraulic Retention Time (HRT) and volume of samples by using Response Surface Methodology (RSM). The samples were taken from the direct discharge point of the laundry greywater at two houses. The results revealed that the efficiency of designed filtration system depended on HRT and volume of samples. The highest Chemical Oxygen Demand (COD) removal from 1 L of LGW and after 3 hrs was 43.31%, while the highest removal of orthophosphate (PO4) (100%) and sodium (Na) (27.48%) were recorded with 2 L and after 2 hrs. It can be concluded that the ceramic waste coarse aggregate filtration was effective in reducing the pollutants in the LGW before the final disposal into the environment.Ceramic waste, laundry greywater, optimization, quality, RSM, removal
5
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(Downloads: 4)
Abstract (Viewed: 1)This paper highlights basic data collected over the 7 years and 8 years of establishment of the marine turtle hatchery projects in Pulau Rusukan Besar Marine Park Centre (PRBMPC), Federal Territory of Labuan and Pulau Redang Marine Park Centre (PRMPC), Terengganu; Malaysia, respectively. Compiled data were taken from year 2010 until 2017. The within and between season patterns in terms of nest number of the green (Chelonia mydas) and hawksbill (Eretmochelys imbricate) turtles were shown. The population of marine turtles were estimated from the number of nests laid. Total annual nests were used as a crude index of female turtle abundance. Green turtles accounted for 96.18% (1,233 nests laid) of the total nesting recorded while hawksbills accounted for the remaining 3.82% (49 nests laid) in the PRMPC. However, in the PRBMPC 23.58 % (29 nests laid) and 76.42% (94 nests laid) were recorded respectively for the green and hawksbill turtle. 100 % of the nest laid have been incubated using the ex-situ conservation method with the production of 103,929 and 23,558 live green and hawksbill turtle hatchlings respectively. The 8-year average hatching and emergence success rates for green turtles and hawksbills were 87.11 and 88.33%, and 91.56 and 90.69% respectively. This paper provides important information that is fundamental for the understanding of population status to ensure effective conservation measures and management of marine turtles at both marine parks.Chelonia mydas, Eretmochelys imbricate, Green turtle, Hawksbill turtle, nesting
6
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(Downloads: 4)
Abstract (Viewed: 1)High concentration of iron (Fe) levels (above 1.0 mg/L) in water causes bad taste, staining and deposition in pipes and results in high turbidity in water supplies. Existing treatment technologies (which have been conventionally applied to remove Fe ions), are expensive and cause toxic sludge production. A set of experiments was carried out to evaluate the Fe uptake potential of spent coffee grounds by conducting batch tests in an aqueous solution through a biosorption process. Batch sorption studies were conducted based on pH, contact time, adsorbent dosage and adsorbent particle size. In addition, initial metal concentration was investigated. Flame atomic adsorption spectroscopy analysis revealed that the maximum adsorption recorded was 0.470 mg g-1 by using 0.30 g of 210-355 µm coffee with the maximum uptake percentage of Fe (92.9%) for 60 minutes at pH 4. Adsorption behavior of Fe ions on a surface of coffee grounds was well-interpreted by Langmuir model (R2 = 0.999). A kinetic study indicated that the Fe ions uptake was well-fitted by the pseudo second-order reaction model with good correlation (R2 = 0.993). The study offered an affirmative answer to the hypothesis of reusing eco-friendly and low-cost coffee grounds for removal of Fe ions from polluted waters.Adsorption, green technology, iron, spent coffee grounds, water pollution
7
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(Downloads: 7)
Abstract (Viewed: 1)Radon concentration levels in water from lead contaminated Kawo and Magiro communities in Rafi Local Government Area were assessed using RAD-7. The mean radon concentration in the areas ranged from 35.02 to 175.10 Bq L-1; while the weighted mean concentration was 87. 55 Bq L-1. The resulting weighted mean annual effective dose in the two communities for stomach were 30.64 µSv y-1, 23.08 µSv -1 and 18.38 µSv -1 for infant, children and adults respectively. The mean and weighted mean concentrations in all the samples exceeded the maximum contaminant level recommended by International Organization. Forty five (45%) of the samples exceeded 100 Bq L-1 recommended by EU and WHO.Contaminated, Kawo, Magiro, radon, water
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(Downloads: 6)
Abstract (Viewed: 1)The problem in this research is monitoring the forest fire disasters in South Kalimantan Province, Indonesia. One form of technology that can be applied to support the forest fire prevention activities is remote sensing satellite technology. The objective of this research is to analyze the ability of the Landsat 8 OLI TIRS for monitoring post-fire forest changes based on the ΔNBR and ΔNDVI values. The data used in this research were ΔNBR and ΔNDVI generated from Landsat 8 OLI data record from August 11 to September 6, 2017. The research showed that burned areas in South Kalimantan Province could be identified from the Landsat 8 OLI imagery based on changes on the ΔNBR and ΔNDVI values. The former burned areas during the 2017 fire season in South Kalimantan Province (August- September) were mostly found in some regency such as Banjar, Hulu Sungai Utara, Hulu Sungai Selatan, Tapin, Tanah Laut, and Banjarbaru. The Landsat 8 OLI TIRS has longer spectral bands. The use of the NBR index using the SWIR band makes the Landsat 8 OLI TIRS to be more preferred than other imagery.Burned Area, Landsat 8 OLI, NBR, NDVI JST-1406-2018
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(Downloads: 5)
Abstract (Viewed: 1)This study attempts to develop a soil moisture measurement system with a monopole antenna sensor, mini-VNA Tiny and a mobile phone respectively. The mini-VNA Tiny is a compact vector network analyzer (VNA) with a USB connection to a smartphone or a tablet. There are 17 sets of data which have been collected from 15 different spots with varying soil moisture content. The actual moisture content on site was collected from TRIME-PICO 64/32 sensor. Upon collection, it was necessary to calibrate the resistance obtained from the mini-VNA between 1 MHz and 3 GHz. The data obtained from the study shows that the resonances of the antenna resistance shift to the left on the frequency spectrum as moisture content increases. A linear model relating the resistance and actual moisture content was developed from this study with coefficient of determination (R2) value of 0.723 at 13 MHz. This value is much less than the anticipated R2 = 0.95 for accurate measurement of soil moisture with monopole antenna at microwave frequency. This could be due to the 0.60 cm thickness of the monopole antenna which may not be suited for soil moisture measurement. Nonetheless, this study demonstrates the potential application of an inexpensive and portable mini-VNA Tiny and smartphone system for sensing applications.Monopole antenna, resistance, sensor, soil moisture, VNA
10
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(Downloads: 5)
Abstract (Viewed: 2)The wideband frequency spectrum, such as UWB, also consists some narrowband services like WiMAX and WLAN. Therefore, the possibility of interference between wideband and the narrowband services increases. Generally, an additional filter is used to overcome the interference issues, but, the use of additional filter increases the cost and complexity of the system. Earlier, a truncated patch antenna with C-shaped slot has been proposed to optimize the cost and complexity, but, it fulfils the band rejection requirement for WLAN (5-6 GHz), while, it does not support the reconfigurability. An optimized planar ultra-wideband (UWB) antenna with WLAN band-reconfiguration characteristic fed by a 50 Ω coplanar waveguide (CPW) has been proposed in this paper. In this proposed structure, the truncated metal patch consists two additional symmetrical open stubs and the patch and the stubs are connected through MEMS switches to achieve the reconfigurable property. The overall dimension of the antenna is 19×18×1.6 mm3 and integrated on FR4 substrate. The proposed design has shown wideband impedance matching in terms of radiation pattern and gain along with reconfigurability.Band-notched UWB antenna, coplanar waveguide (CPW), C-shaped slots, frequency reconfigurable, LCR circuit, MEMS switch
11
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(Downloads: 3)
Abstract (Viewed: 1)Notably in the construction industry, procurement is evidently important and cannot be played down because it constitutes every phase of a project delivery system. The low-bid system has remained the most popular procurement system globally. In Nigeria, it lacks transparency and accountability. Therefore, the Nigerian Procurement system has shown a need to be stabilised by shifting risk and control to the expert who has the duty to act in the client's best interest by adopting "Best Value Performance Information Procurement System (BVPIPS)" in contractor selection. This paper aims at identifying factors that can hinder the implementation of this innovative procurement system and their relative influence. A total 314 questionnaires were distributed to 5 construction industry professionals in Nigeria they are: Architects, Quantity Surveyors, Civil Engineers, Builders and Services Engineers. The data collected were presented and analysed using: cross tabulation, exploratory factor analysis and mean score ranking using Statistical Package for Social Sciences (SPSS) version 24 and Microsoft Excel respectively. Likert scaling was used to measure the level of agreement of the respondents. The paper found out that the social factor, political factor, procurement environment factors and the cultural factor in the construction industry ranked 1, 2, 3 and 4 respectively and which factors have a very strong relative influence on hindering the implementation of BVPIPS in the Nigerian construction industry. The implication of this study is, to help construction practitioners, researchers, academics, industry players, and other stakeholders to look into the significant issues that can hinder the implementation of PIPS in Nigeria and make better the delivery of projects in the construction industry. Therefore, these factors identified should be considered and precautionary measures taken when implementing BVPIPS in the Nigerian construction industry so as to accommodate innovative approaches such as BVPIPS to improve project delivery in Nigeria.Best Value Performance Information Procurement System (BVPIPS), construction industry, innovation, Nigeria, performance, procurement methods, project delivery value
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(Downloads: 4)
Abstract (Viewed: 1)Water stress and sensitive coefficient of crops are important parameters, indicating the effect of water regime on productivity. They provide a scientific basis for management agencies and farmers to manage and operate their irrigation systems. A field experiment was carried out on an area of 450m2, divided into 42 experimental plots with different cultivation methods (conventional and SRI) and under different water regimes. Measurement parameters of each plot included irrigation water, rainfall, in-flow, evapotranspiration, capillary water going up while the surface soil layer was revealing and drying, in/out underground water flows in cultivating soil layer, infiltration water, difference of water levels on the experimental plots at the beginning and end of the study. Evapotranspiration in each growth stages of rice crops and in each experimental plot was determined. Then Jensen's yield prediction model was calibrated to predict rice yield as affected by the water stress. The result revealed that if water shortage had occurred, the yield of spring rice which was cultivated following SRI methods would be less than that cultivated by conventional method. Moreover, the effects of water shortage in 1st and 2nd growth stages of conventional cultivated summer rice were less than that cultivated following SRI method in the same stages. The yield of rice crops cultivated following the SRI method was less affected by the lack of water in 3rd and 4th growth stages, as compared to that cultivated by conventional method.Crop growth stages, rice, sensitive coefficient, water regimes, yield prediction model
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(Downloads: 3)
Abstract (Viewed: 1)Synthetic jets have been utilized for various active flow control applications including control of boundary layer transformation/detachment, lift enhancement and drag reduction, heat transfer enhancement by cooling of microprocessors in electronic industry and mixing augmentation. Numerical examination is performed to address the effects of excitation voltages and actuation frequency on the characterization of synthetic jet fluidics. The present study also explores the heat transfer improvement by a synthetic jet actuator having two cylindrical orifices arranged at the top of cavity opposite to heated thin stainless steel foil. The diameter of each orifice of the synthetic jet actuator is 2 mm with the spacing being 4 mm. The excitation voltages for actuation are taken as 20 V, 30 V, and 55 V. The computation is carried out by using Commercial software COMSOL 5.3a Multiphysics for solving three dimensional incompressible unsteady Reynolds-averaged Navier-Stokes equations with an established Shear- Stress-Transport (SST) k-ω turbulence model coupled with piezoelectric and ALE Moving Mesh technique describing the diaphragm movement. The qualities of the extracted results from the present study are authenticated by grid density, time and domain independence studies and are validated with the existing experimental data. Results show that the radial and axial velocities at the orifice exit of synthetic jet actuator tend to approach maximum at 55 V and the average heat transfer coefficient due to double cylindrical orifice is 32 % higher to that of a single orifice synthetic jet actuator with constant cavity volume thereby leading to better performance.Active flow control, boundary layer detachement, comsol multiphysics, heat transfer enhancement, Piezoelectric Diaphragm, synthetic jet fluidics.
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(Downloads: 6)
Abstract (Viewed: 1)In this study, papaya (Carica papaya) peel was dried using convection oven and microwave drying methods to investigate the drying kinetics and the drying behavior in the attempt to search for a feasible way to utilize waste peel. Three different drying temperatures (45, 55, and 65 °C) and microwave powers (250, 440, and 600 W) were applied to dry the papaya peel, wherein the drying data were fitted into the following seven drying kinetic models: Lewis, Page, Modified Page, Henderson and Pabis, Logarithmic, Two-Term, and Approximation of Diffusion models. The study outcomes indicated that the Page model emerged as the best fitted model for oven drying of papaya peels with the highest coefficient of determination (R2) value (0.994-0.996) for all the three temperatures. As for microwave drying, the Approximation of Diffusion model exhibited the best fit owing to the highest R2 value (0.996-0.999) for all the three powers. The effective moisture diffusivity values for convection oven and microwave drying methods ranged from 6.65 x 10-08 to 4.35 x 10-07 and from 2.43 x 10-07 to 6.67 x 10-07, respectively. Additionally, the activation energy values were recorded at 61.301 kJ/mol and 46.621 W/g for oven and microwave drying methods, respectively.Activation energy, convection oven drying, drying kinetic models, effective moisture diffusivity, microwave drying, papaya peel.
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(Downloads: 4)
Abstract (Viewed: 1)The load forecasting aims at the energy management in the field of power supply systems. It helps to diminish the production cost, spinning reserve capacity and enhance the reliability of the power system. It is tremendously essential for financial institutions, electric utilities and other participants in electric energy market, be it for transmission, generation or distribution. The economic allotment of electricity generation plays a vital role in short term load forecasting. This paper presents a solution methodology based on Levenberg Marquardt algorithm of an artificial neural network technique for short term load forecasting. The system data for forecasting the load includes the parameters like dry-bulb temperature, dew point temperature, humidity and load data. The live load data was recorded from the 66kV substation located at Bhai Roopa, Bathinda in Punjab state of India. The corresponding weather data was collected from the Indian Meteorological Department "IMD" at Pune in Maharashtra state for the years 2015 and 2016. The Levenberg Marquardt algorithm had been implemented to minimize the error function derived on the basis of computed load and actual load. This work had been carried out using the MATLAB software. The obtained results would support an effective and accurate load forecasting in future.Electrical energy, feed forward network, Levenberg Marquardt, neural network, short term load forecasting
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(Downloads: 4)
Abstract (Viewed: 1)The breast cancer automatic diagnosis is a critical real world medical challenge. This study proposes a classifying cancer tumor method based on their gene expression signatures to specific diagnostic categories. The developed neural network model holds promise for patients, surgeons, and radiologists, providing them with information, which was only available using biopsy. This significantly reduces the number of pointless surgical procedures. This study utilizes Wave Atom Transform as feature extraction method, and Back Propagation Algorithm to classify cancer into pre-defined classes. The proposed model provides automatic detection with a high level of accuracy (90%).Back Propagation Network (BPN), breast cancer diagnosis, neural networks, wave atom transformation
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(Downloads: 4)
Abstract (Viewed: 1)Recently, there is a heightened level of awareness towards energy efficiency in high-performance data centers both to reduce environmental pollution and save cost. Such data centers consume massive amount of energy for processing huge computational requirements from users. These supercomputers demand a constant supply of electricity to be available 24/7 for both its core computing functions as well as cooling the data center. Previously, researchers had introduced various strategies for achieving energy efficiency. However, in order to achieve a truly effective energy management, factors that influence energy usages must also be taken into consideration. The failure to manage such factors leads to excessive energy consumption. In this work, we shall focus on factors relevant to running the operation of high-performance data centers. We reconstructed and analyzed such factors or attributes based on the universally accepted Reduce, Reuse and Recycle Concept (3R). We recategorized energy attributes of the existing Energy Efficient Data Center Frameworks (EEDCFs) to be aligned with 3R. Then, we developed energy-saving algorithms in response to the concept. Our framework was then measured according to the performance metrics namely power usage effectiveness (PUE), energy reuse effectiveness (ERE) and carbon usage effectiveness (CUE) against variability size of data center. The simulation results of our EEDCF showed that better energy saving is achieved in comparison to the existing EEDCFs. This signifies that the application of the 3R concept in energy consumption yielded a promising result as a platform for other researchers to explore more on energy renewal initiatives and embrace it for future application.Data center, energy efficient framework, energy management, simulation.
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(Downloads: 7)
Abstract (Viewed: 1)This paper deals with the trajectory tracking control problem for electrically driven redundant robot manipulators. By combining actuator dynamics with manipulator's kinematics and dynamics, a novel control scheme is proposed for the electromechanical system. In this electromechanical system, the controller is designed at the dynamic level as well as at the actuator level. In the proposed control scheme, uncertain non-linear mechanical dynamics is approximated with the model-based controller combined with the model-free radial basis function neural network based controller together with adaptive bound. The behaviour of the uncertain electrical dynamics is approximated with the help of a radial basis function neural network. The designed controller achieves both the trajectory tracking and the subtask tracking effectively. Additionally, the designed control scheme controls the direct current motors being used to provide the desired currents and torques. The errors are shown to be asymptotically converging and the control scheme is shown to be stable using Lyapunov stability theory. Finally, the simulation results are produced for the rigid link electrically driven redundant robot manipulators to show the effectiveness of the proposed control scheme.Actuator dynamics, lyapunov stability, radial basis function neural network, redundant manipulators, subtask tracking
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(Downloads: 4)
Abstract (Viewed: 1)Security is the primary and integrated requirement for public networks. Internal authenticated attackers are more unfriendly and dangerous to the network. In this paper, a probabilistic Dempster Shafer method is applied to the communication behaviour of network nodes. A prior analytical observation over the communication was done in terms of upper and lower bounds. The upper bound is considered as the belief measure and the lower bound is taken as plausibility factor. The probabilistic belief-to-plausibility measure is obtained for communication delay, failure ratio and energy parameter. As the abnormal activity pair was identified, a verification check was performed before blocking the misbehaving node. The Dempster-Shafer based belief theory was applied to isolate the attacker node and to generate the safe path over reliable nodes. The decision rule was integrated to the work behaviour of the AODV (Ad hoc On-Demand Distance Vector) protocol for the preventive route formation. The simulation results show that the method has improved the communication PDR (Packet Delivery Ratio) ratio and reduced the drop rate and energy consumption as compared to AODV and DSR (Dynamic Source Routing) protocols.AODV, attack preventive, Dempster Shafer, mobile network, security
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(Downloads: 4)
Abstract (Viewed: 1)The use of coconut in the food industry is determined by the condition of its fruit ripeness level, which is very difficult to be conducted. The suitable non-invasive sensing method is the application of computer vision. The purpose of this study is to identify the coconut ripeness level based on several parameters of fruit volume, coconut flesh thickness, and coconut flesh weight by using Artificial Neural Network (ANN) modeling. The best ANN model resulted in 14 inputs consisting of color, texture, shape and size parameters. Color features include: Red, Green, Blue, Hue, Saturation, and Intensity. Textural features include: contrast, correlation, energy, homogeneity. The shape and size parameters include area, perimeter, eccentricity, and metric. The best ANN structure consisted of 14 inputs, one hidden layer with 100 nodes, and 3 outputs of coconut ripeness (indicated by coconut water volume, coconut flesh thickness and wet weight of coconut flesh). The best ANN model produced the smallest Mean Squared Error (MSE) training and MSE testing values of 0.002155 respectively of 1 and 0.90331. Thus, computer vision and ANN models can be utilized to predict the coconut ripeness level.Artificial neural network, coconut ripeness, computer vision, texture analysis and 0.107265 with actual value correlations and predictions as measured by R-training and R-testing
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(Downloads: 7)
Abstract (Viewed: 1)Hepatitis C infection is a major public health problem that can be dealt with urgent and timely attention. Recently, WHO Global Hepatitis Report showed that 71 million people, equivalent to approximately 1% of the world population, are infected with hepatitis C. The disease incidence, mortality rate and risk factors vary across geographical regions. The virus is transmitted primarily through drug injection and exposure to infected blood products in healthcare and community settings. The common causes of death related to virus infections are decompensated liver cirrhosis and hepatocellular carcinoma. Hepatitis C infection is mainly prevented by identifying and controlling any possible risk factors for virus transmission because treatment is costly and limited in availability. In this review, articles discussing the natural history, epidemiology and risk factors for hepatitis C infection are reviewed.Epidemiology, hepatitis C virus, infection, mortality, risk factors, transmission
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(Downloads: 5)
Abstract (Viewed: 1)After coronary artery bypass graft surgery (CABGs), repeat revascularization is often necessary due to progressive atherosclerosis of coronary arteries and grafts, poor patency, limited longevity, and higher risk of redo CABGs. However, data regarding percutaneous revascularization among post-CABGs patients are limited. In this cohort study, 83 subjects with a history of CABGs and recent percutaneous coronary intervention (PCI) at Ekbatan University Hospital were recruited, between January 2013 and January 2017. We followed them at 1-year intervals to evaluate the prevalence of major adverse cardiac events (MACE). The mean duration of follow-up was 28 months. The mean age of the patients was 63 years, and 75% were male. One hundred and three target vessels had undergone PCI with 109 stents, of which 90% were drug-eluting stents (DES). Procedural success was 90%. 19.6% of the procedures were performed on grafts. Mean angina class decreased by one during follow-up, from 2.94 to 1.8. Thirteen patients suffered MACE with 5 cardiac death, 4 nonfatal myocardial infarction (MI), and 8 repeat revascularization, of which 4 were target vessel revascularization. The rate of MACE at one, two, and three years was 17.5%, 25%, and 35%, respectively. Based on univariate analysis, graft PCI was an independent predictor of MACE. Cardiac death can be predicted by age, left ventricular ejection fraction (LVEF), and history of MI. For patients with a history of CABG and recurrence of symptoms, PCI is considered as an efficient and risk-free modality, which can be relied on to alleviate symptoms.Coronary arteries bypass surgery, MACE, repeat revascularization
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(Downloads: 3)
Abstract (Viewed: 1)Unintentional injuries cause huge economic and social burden for the country. To further prevent unintentional injury by different age groups, it is crucial to identify the recent pattern of paediatric mortality. For a start, this study included a retrospective record review of 334 paediatric trauma patients (0-18 years) who were hospitalized due to unintentional injuries. The patient's medical records from the period 2007 to 2010 were obtained from the National Trauma Database (NTrD). The patients were categorized into <1, 1-4, 5-9, 10-14 and 15-18 years of age. Data entry and analysis were accomplished using IBM SPSS version 22. Most of the patients were Malay (78.4%), male (82.9%), died in hospital (33.2%) and total fatality by unintentional injuries for four years rose by nearly 59.5%. Death occurred with some monthly variance demonstrated with three mortality peaks in March, April and December. The proportion of unintentional injuries death was 33.0% (95% CI 0.28, 0.38). Malay male patients had higher risk of death compared to female patients. Effective program and preventive measures should be implemented to reduce mortality.Adolescent, children, paediatric, pattern, proportion, unintentional injury
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(Downloads: 10)
Abstract (Viewed: 1)This study reports the results of an experimental study on mechanical properties of plain and metakaolin (MK) concretes with and without steel fiber. To develop the metakaolin reinforced concrete, Ordinary Portland cement was partially replaced with MK 3%, 6%, 9%, 12%, 15%, 18% by weight of the total binder content. Steel fiber with length 50 mm and diameter 0.70 mm was utilized to produce fiber reinforced concrete. Concrete was designed with water to cement (w/b) of 0.464. First water absorption test was investigated then compressive strength and split tensile strength were calculated by replacing metakaolin with cement at the end of 7 days, 28 days, and 56 days of curing period. Again the effectiveness of MK and steel fiber reinforcement with different percentage of steel fiber i.e. 0.25%, 0.5%, 1% of the weight of cement was taken. Then the compressive, split tensile strength of the concretes was investigated. All tests were conducted at the end of 7 days, 28 days, and 56 days of curing period. It was found that for replacement of metakaolin the compressive strength and split tensile strength were increased up to 9% replacement of metakaolin and decreased after that. It gave the maximum value at 9% of replacement of metakaolin. Addition of steel fiber to the different percentage of metakaolin also increased the strength then that of metakaolin reinforced concrete. The results revealed that incorporation of MK and utilization of different types of steel fibers significantly affected the mechanical properties of the concrete.Compressive strength, curing, metakaolin, steel fiber, split tensile strength
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(Downloads: 7)
Abstract (Viewed: 1)In recent years, digital cameras have become one of the tools used by the new generation due to their unique advantages in capturing and processing data and usage in many applications, such as crop growth, forest monitoring and archaeological investigation. The quality of images captured by digital cameras originate from accurate measurements which are allied to the digital internal camera parameters. Instability of geometric cameras require consideration to achieve good accuracy in measurement. Therefore, camera calibration becomes an important task to ensure the stability of all internal camera parameters. This research is aimed to assess the internal camera parameters of non-metric cameras. The quantitative method was adapted by this research, which required an experimental implementation achieve quality in data acquisition. Several camera parameters needed to be emphasised in regard to camera calibration, which consisted of focal length, offset main point, radial lens distortion, and distortion of tangent lenses. The offset main point represents the image centre coordinates while the distortion of tangent lenses ensures image quality during image acquisition. The study found that Nikon SLR D60 camera provided a higher accuracy as compared to DJI 4 pro and iPad mini 4 cameras. In conclusion, all non-metric cameras can be used for mapping but it will provide various accuracy levels.Camera, parameter, self-calibration, unmanned aerial vehicle
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(Downloads: 4)
Abstract (Viewed: 1)Tripoli coastal aquifer, Libya, which is located in a densely urbanised area, is the primary source of water supply in Tripoli city. In the last few decades and due to population growth, more than 100 wells have been drilled in Tripoli aquifer for the purpose of increasing pumping to meet demand on groundwater. The urbanisation at the Tripoli upper aquifer system has reduced the recharge rates and affected the groundwater storage. In this study, changes in groundwater dynamics in Tripoli's unconfined aquifers were simulated using MODFLOW-2005 code. The model was calibrated and validated using measured and simulated values. Statistical tests such as coefficient of determination, R2 mean error, mean absolute error, and the root mean square error were computed and found to be 0.97, 0.31, 1.70 and 2.32 respectively. The simulation will assist in the assessment of the long term saline water intrusion. Calibrated transient groundwater flow models for the years 2020 – 2100 indicated that this case is likely to occur along pumping profiles with high pumping rates. Simulation results show that the groundwater levels will decline and exceed 12 m in the Southern area while in the Northern area near the coastal line, depletion is continuous and more than 70 wells will face saline water intrusion by the year 2100. Doubling the pumping rate from the wells will accelerate the drop in the groundwater levels and about 98% of the wells will be subjected to high salinity level by 2100. The salinity levels in these wells will make the groundwater unfit for human consumption.Groundwater levels, MODFLOW-2005, saline water intrusion, simulation, tripoli aquifer
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Abstract (Viewed: 1)Degradation of coastal water quality is one of the major concern in the Malacca Strait since this area is one of the most important fishing ground in Malaysia. Despite being great in the fishery industry, Malacca and Negeri Sembilan somehow recorded the lowest marine fishes landing, which raises a question about dynamics of this area. It is therefore, a preliminary study of the physical properties and nutrient concentrations carried out from 27 March to 4 April 2016 at the coastal water off the southern west coast of Peninsular Malaysia, specifically at Pulau Besar, Malacca and Tanjung Tuan, Negeri Sembilan. Data for temperature, salinity, and dissolved oxygen (DO) was acquired by using Conductivity, Temperature, and Depth (CTD) probe. Meanwhile, nutrient concentrations determination in this study was done by using a Westco Smartchem 200 Discrete Analyser, according to the procedure adopted from United States Environmental Protection Agency (USEPA). In general, results of this study indicated the coastal stations were characterised with cooler, less saline, and high DO waters than stations away from coast. Large sea surface heating and weak winds were determined as the causative factors affecting dynamics of water column at the study area. At nearshore area, temperature, salinity, and DO variability were modulated by degree of freshwater intrusion. High nutrient concentrations at the stations closer to the coast was believed to be associated with river outflow, which acted as the main source of nutrients supply in this area. Comparison to previous study had shown that nutrient concentrations in this research were low, which could contribute to an insight on declining marine fish catches in these two states. With regard to Malaysian Marine Water Quality Criteria and Standard (MWQCS), mean nutrient concentrations at the study area were in Class 1, which are suitable for marine parks and marine protected areas conservation. Regardless of limited scope, the outcome of this study is believed to be a good baseline reference for future studies seeking to understand coastal dynamics.Freshwater intrusion, Malacca Strait, nutrients, physical parameters, preliminary study
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Abstract (Viewed: 1)The use of starch as bioplastic has been widely studied; however, the quality needs to be improved before it can substitute the commercial plastic. Sago is one of starch sources that can be used for this purpose and is available in considerable amounts in Indonesia. Previous research to synthesize a modified sago starch thermoplastics (TPS) in-situ by reacting plasticized starch with diphenylmethane diisocyanate (MDI) and castor oil; simultaneously to produce polyurethane prepolymer (PUP) in more homogeneous phase and smaller size has been successfully done. At this phase, chitosan of 0.5, 1, 1.5, 2 and 2.5 gram was added into the compound and acted as filler to improve the mechanical and thermal properties of TPS. The chitosan was first diluted into acetate acid and mixed rigorously with the starch and PUP. Sorbitol was added as plasticizer. The modified TPS-chitosan was then characterized mechanically, thermally, and biodegradability. The results of this study showed that the optimum mechanical properties of modified TPS were obtained with an addition of 1 gram chitosan; tensile strength and elongation were 200.04 MPa and 24.96 % respectively. Thermal Gravimetric Analysis showed that modified TPS-chitosan had a good thermal stability and could only be degraded at high temperature of 534°C. DSC result showed that modified TPS-chitosan had a high melting point of 385.41°C and ΔH152.61 J/g. This value is higher than melting point of TPS alone which is 104.69°C. Modified TPS-chitosan was degraded earlier than TPS which was 19 days in nature compared to 2-4 months. Overall, mechanical and thermal properties of modified TPS are improved with the addition of chitosan.Biodegradability, chitosan, mechanical properties, Modified Thermoplastic Starch (TPS), sago, thermal characteristics
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Abstract (Viewed: 1)This paper presented how to partition a network in a number of zones. Once a zone has been determined first node to end node, it is time to decide on the location of stationary facilities within the zone. Location decisions belong to the node and it depends on the type of service being offered. In some cases, the imperative concern is to minimize the average distance or the facilities for the population. Approaches to location and models for applying location policy, two major classes of considerations are highly instrumental in selecting an approach to solving; this concern is usually dominant for cases such as locating a post office, a transportation terminal, or an office of a government agency. One class relates to management objectives, the other class is concerned with the nature of the demand for services and nature of the service provided.Network, policy, service, stationary facilities, zone
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Abstract (Viewed: 1)Sound is a form of wave vibrations that contributes significantly in our daily life. Plants may interact with sound around us but we cannot certainly sure their reaction because of their immobility. Thus, this study intends to find the significant effect between different types of acoustic patterns on the growth of plants. Mung bean or its scientific name, Vigna radiata was chosen as seed material in this experiment due to their short growth cycle. The plants were grown in six environmental chambers with proper ventilations. The chambers were placed on open field with ambient conditions. Mung beans were exposed to five different types of acoustic patterns (soprano, classical, nature, rock, Quranic recitation) with sound pressure level of 60 dB ± 10 dB and one chamber was kept without any acoustic exposure. The length of stem, number of leaves and length of roots were recorded on the 15th day of mung beans' growth. Experimental results indicate that different types of acoustic patterns promoted the growth of different part of mung beans. Soprano had significant effect on the length of stem while Quranic recitation promoted the production of leaves. However, there is no significant evidence that acoustic exposure stimulates the length of roots.Acoustic exposure, multivariate analysis, mung bean, plant growth

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