Universiti Putra Malaysia
Download Latest Complete Journal - JST Vol. 22 (2) Jul. 2014
Foreword by the Chief Executive Editor
No.ArticlesDownloads
1
Full Article
(Downloads: 25)
Abstract (Viewed: 5)Bifurcation and chaos are important phenomena affecting many physical and chemical systems. They are also related to the stability/instability and multiplicity phenomena associated with these systems. The phenomena are not only of theoretical/mathematical interest but are also important for laboratory, pilot plant and commercial units. This paper concentrates on 3 systems:

1. The novel auto-thermic Circulating Fluidized Membrane Steam Reformer (CFBMSR) for the efficient production of the clean fuel hydrogen and which shows multiplicity of the steady state (static bifurcation)

2. A novel fermentor for the efficient production of bio-ethanol that shows static/dynamic bifurcation as well as chaotic behaviour

3. The neurocycle of the acetylcholine transmitter in the brain using diffusion-reaction models in order to gain insight into their possible connection to Alzheimer and Parkinson Diseases (AD/PD); these are preliminary efforts to investigate the bifurcation and chaotic behaviour of this neurocycle.
Bifurcation, multiplicity, chaos, CFBMSR, chemical/biological reaction engineering, neurocycle, Alzheimer and Parkinson Diseases (AD/PD)
2
Full Article
(Downloads: 23)
Abstract (Viewed: 3)In this study, various methods and applications of flat plate solar collectors are discussed and pictorial representations are presented. Low temperature applications of flat plate collectors are identified in solar cooking, solar water heating, space and air heating, industrial heating plants and in agricultural produce drying processes. Basic equations, as presented by many researchers in the performances of flat plate collectors, are also presented. The review discusses the analysis of losses from flat plate collectors towards obtaining the overall heat loss coefficient which indicate the performance of flat plate collectors.Flat plate collectors, air heating, water heating, heating and cooling of buildings, solar drying
3
Full Article
(Downloads: 16)
Abstract (Viewed: 3)The aim of this study was to compare physical activity prevalence estimates among the International Physical Activity Questionnaire (IPAQ), steps/day, and accelerometer in a sample of government employees in Kangar, Perlis, Malaysia. Ten government agencies in Kangar were randomly chosen, and all employees were invited to participate. A self-administered questionnaire was employed to obtain information on socio-demographic characteristics and a physical activity assessment using the IPAQ. Anthropometric measurements, which include measurements of weight, height, body mass index, percent body fat, waist and hip circumference, were carried out. An accelerometer was used to assess total daily energy expenditure and the number of steps/day. A total of 272 respondents were involved in this study with a response rate of 83.2%. According to IPAQ, accelerometer and steps/day, the majority of the respondents (22.0%, 55.1%, and 77.6%, respectively) were classified as sedentary. The agreement between physical activity level as determined by the accelerometer vs. the IPAQ (Kappa=-0.46 {95% CI -0.384,-0.536}, p=0.238) and the IPAQ vs. steps/day (Kappa =0.037 {95% CI 0.090,-0.016}, p=0.175) was not significant, but the agreement between physical activity level as determined by the accelerometer vs. steps/day was classified as fair (Kappa=0.296 (95% CI 0.392, 0.200}, p<0.001). Our study highlights the need for a valid, accurate, and reliable self-report physical activity assessment tool for Malaysian adults.Prevalence, physical activity measurements, accelerometer, IPAQ, steps/day.
4
Full Article
(Downloads: 22)
Abstract (Viewed: 2)Extreme Value Theory (EVT) is a statistical field whose main focus is to investigate extreme phenomena. In EVT, Fréchet distribution is one of the extreme value distributions and it is used to model extreme events. The degree of fit between the model and the observed values was measured by Goodness-of-fit (GOF) test. Several types of GOF tests were also compared. The tests involved were Anderson-Darling (AD), Cramer-von Mises (CVM), Zhang Anderson Darling (ZAD), Zhang Cramer von-Mises (ZCVM) and Ln. The values of parameters µ, σ and ξ were estimated by Maximum Likelihood. The critical values were developed by Monte-Carlo simulation. In power study, the reliability of critical values was determined. Besides, it is of interest to identify which GOF test is superior to the other tests for Fréchet distribution. Thus, the comparisons of rejection rates were observed at different significance levels, as well as different sample sizes, based on sever l alternative distributions. Overall, given by Maximum Likelihood Estimation of Fréchet distribution, the ZAD and ZCVM tests are the most powerful tests for smaller sample size (ZAD for significance levels 0.05 and 0.1, ZCVM for significance level 0.01) as compared to AD, which is more powerful for larger sample size.Critical values Fréchet distribution, goodness-of-fit, rejection rate
5
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(Downloads: 15)
Abstract (Viewed: 2)A study on the distribution of Recent Ostracoda in offshore sediment was carried out around the South China Sea. A total of 30 sediment samples were taken from the sampling stations between latitude 1°48' and 7°25'N and longitude 102°09' and 105°16'E. From this study, 79 species of ostracods belonging to 16 families and 44 genera were identified. The dominant species was Foveoleberis cypraeoides with 937 individuals obtained. There were 13 to 43 species in total. Diversity Index, H(s), was in the range of 2.1to 3.3, whereas the dominance values were between 4.4 and 14.7%. Several environmental parameters were measured including depth, temperature and salinity. The range values for each of these parameters are 13-72 m, 25.24-30.06°C and 27.74-34.91 ppt, respectively. The sediment texture in this study area can be categorized as sand, sandy mud, clayey mud, silty mud, silty clay, clayey sand, clayey silt and silty sand. The observations revealed that abundance and diversity of ostracod appeared to be principally controlled by depth. Two faunal assemblages were identified in terms of faunal composition, namely, shallow water (Hemikrithe orientalis, Neomonoceratina iniqua, Stigmatocythere indica, Cytherelloidea leroyi and Neocytheretta snellii) and deep water (Paracypris sp., Alataconcha pterogona, Bythocytheropteron alatum, Keijella paucipunctata and Actinocythereis scutigera). A comparative analysis showed a high degree resemblance between the study area and south-eastern Malay Peninsula (the South China Sea).Abundance, diversity, Recent Ostracoda, depth, assemblages
6
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(Downloads: 15)
Abstract (Viewed: 2)HCFCs, in addition to destroying the ozone layer, have been recognized as a contributing factor that increases global warming. It is widely used as working fluid in window air-conditioning system, where capillary tube serves as an expansion device. Literature reports have shown that no single refrigerant can solve the problem of ozone layer depletion and global warming. Refrigerant HC290/HC600a/HFC407C mixture, an eco-friendly refrigerant, has been recognized as an alternative to HCFC22. The objective of this study is to, for cost effectiveness, develop an empirical correlation to predict the refrigerant HC290/ HC600a/HFC407C mixture mass flow rate using statistical experimental design approach. A review of relevant literature shows that refrigerant's mass flow rate depends on condensing temperature, degree of subcooling, inner diameter and length of capillary tube. The relationship between the mass flow rate and the four independent variables was established as an empirical mathematical correlation using central composite design (CCD), a response surface methodology (RSM). This empirical correlation was examined using analysis of variance (ANOVA) of 5% level of significance. The results of these analysis showed that the correlation fitted well with the experimental data yielding an average and standard deviation of 1.05% and 2.62%, respectively. The validity of the present correlation was further assessed by comparing it with published empirical correlation in literature and the result showed that the present correlation is consistent.Ozone layer, air-conditioning, capillary tube, refrigerant, empirical correlation
7
Full Article
(Downloads: 16)
Abstract (Viewed: 6)Identification of hot spots is an important issue in proteomics. Identifying hot spots using Digital Signal Processing (DSP) based methods is quite useful in newly discovered proteins as these methods do not require the structural information of proteins. In this paper, Modified Gabor Wavelet Transform (MGWT) was used to predict hot spots from primary amino acid sequence of protein. Incorporation of MGWT into Resonant Recognition Model (RRM) improves the prediction of the hot spots. The proposed method only requires tuning of MGWT to the characteristic frequency of the proteins' functional group, which is determined using RRM. This DSP-based technique is illustrated using several protein examples and the results are compared with the other recently reported digital signal analysis methods, viz. digital filtering and S-Transform based approaches. Relative procedural simplicity of this method over S-transform based approach and better prediction performance than digital filtering method are the novel features.Electron-Ion-Interaction-Potential, Hot spot, protein, resonant recognition model, wavelet transform
8
Full Article
(Downloads: 7)
Abstract (Viewed: 3)During recent years, extensive development has been made to improving vaccines for tuberculosis. This is due to the presence of genome sequences of diverse mycobacterial species and Mycobacteroum tuberculosis (M. tuberculosis) isolates which has led to advances in the characterization of genes and antigens of M. Tb and better realization of protective immune responses to the disease in both animals and humans. This review summarizes vaccine types, reasons for variable efficacy of BCG, latest advances in tuberculosis vaccine development and major vaccine design strategies.Tuberculosis, vaccines, bacille Calmette-Guerin (BCG), Region of difference (RD)
9
Full Article
(Downloads: 11)
Abstract (Viewed: 4)Self-care behaviour involves all activities type 2 diabetes patients engage in to care for their disease. In our local population, however, most patients do not manage their disease appropriately. This study aimed to determine the level of self-care behaviour and to examine the differences in self-care behaviour according to type 2 diabetes patients' demographic data and health condition at University Malaya Medical Centre. Sample of this study comprised 388 patients (respondents) and data were collected from December 2010 to February 2011 using self-administered questionnaires. Results showed that the level of self-care behaviour was moderately high (mean = 38.94, SD=11.93). There were significant differences between self-care behaviour and ethnicity [Wilk's Lambda = 0.92, F(12, 1008) = 2.70, p < 0.05], age group [Wilk's Lambda = 0.96, F(4, 383) = 4.39, p < 0.05], education level [Wilk's Lambda = 0.94, F(12, 1008) = 1.85, p < 0.05], type of treatment [Wilk's Lambda = 0.92, F(12, 1008) = 2.84, p < 0.05], health education [Wilk's Lambda = 0.97, F(4, 383) = 3.33, p<0.05] and smoking status [Wilk's Lambda = 0.96, F(4, 383) = 4.53, p < 0.05]. Respondents who are Indian, elderly, had lower level of education, on insulin treatment, had received health education on diabetes and not smoking had better self-care behaviour scores. It can be concluded that high risk type 2 diabetes patients should be taught individually so as to help them improve physical and psychological outcome.Self-care behaviour, type 2 diabetes
10
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(Downloads: 11)
Abstract (Viewed: 3)Elliptic curve cryptosystems (ECC) provides better security for each bit key utilized compared to the RSA cryptosystem. For this reason, it is projected to have more practical usage than the RSA. In ECC, scalar multiplication (or point multiplication) is the dominant operation, namely, computing nP from a point P on an elliptic curve, where n is an integer defined as the point resulting from adding P + P + ... + P , n times. However, for practical uses, it is very important to improve the efficiency of the scalar multiplication. Solinas (1997) proposes that the τ-adic Non-Adjacent Form (τ-NAF) is one of the most efficient algorithms used to compute scalar multiplications on Anomalous Binary curves. In this paper, we give a new property (i.e., Theorem 1.2) of τ-NAF(n) representation for every length, l. This is useful for evaluating the maximum and minimum norms occurring among all length-l elements of Z(τ). We also propose a new cryptographic method by using randomization of a multiplier n to ñ an element of Z(τ). It is based on τ-NAF. We focused on estimating the length of RTNAF(ñ) expansion by using a new method.Anomalous Binary Curves (Koblitz Curves), Scalar Multiplication, τ -adic Non-Adjacent Form, Norm.
11
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(Downloads: 11)
Abstract (Viewed: 2)Detailed geophysical investigations have been carried out using integrated geophysical methods with a view to characterising the subsurface lithologic features that might indicate suitable places for structural developments. An overview of the subsurface resistivity distribution has been achieved employing 8Vertical Electrical Soundings with the Schlumberger array and 4 2D resistivity imaging using Wenner array. In order to constrain the results of the electrical resistivity methods, we carried out a ground magnetic survey along E-W direction using the Proton precession magnetometer at 1m sampling interval. Analysis of well logs data available and VES results showed 4 to 5 geoelectric layers corresponding to sand, clayey sand, clay, silty sand and sandy clay. The 2D resistivity imaging sections showed relative decrease of apparent resistivity with depth implying a geological transition from sand with high resistivity value of about 508Ωm to clay with low resistivity value 16Ωm at depths of 0-20m and 25-50m respectively. The magnetic profiles showed that the study area was characterised by short wavelengths and amplitudes ranging from –3800 to 700 nT. The highs and lows of the magnetic responses occasioned by lithological variations and structural features were magnetically resolved. In view of the identified subsurface structures, the suggested depth to the competent layer is about 20m for low to medium structures while above 50m would be suitable for heavy or massive engineering structures. The use of integrated geophysical methods for the delineation, identification and imaging of the subsurface geological structures which could provide clues to the nature and type of foundation suitable for the development of the study area has been successfully achieved. Electrical resistivity, Wenner array, sand, magnetic anomaly, constrain, foundation design.
12
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(Downloads: 14)
Abstract (Viewed: 3)Lansium domesticum Corr. is a fruit tree of the Meliaceae family, which is commonly found in South-East Asia with a wide range of varieties. This study investigated three varieties of L. domesticum; Duku, Langsat and Dokong for the phytochemical screening and antimicrobial activity. Seeds from the matured fruits were extracted using hexane, methanol and water. The crude extracts were screened for antimicrobial activities toward three bacteria, namely, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus. The findings showed that Langsat seed extracts contained more groups of compounds compared with the other two varieties, and its methanol extract demonstrated the highest inhibition zones against the three bacteria. The crude methanol extract of Duku seeds showed inhibition zones only towards Bacillus subtilis at a high concentration (1.0 mgL-1), whilst the seed extracts of Dokong showed no inhibition zones towards any of the tested bacteria.Lansium domesticum, antimicrobial activities, inhibition zones
13
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(Downloads: 9)
Abstract (Viewed: 3)A multivariate control chart is a common tool used for monitoring and controlling a process whose quality is determined by several related variables. The objective of this study is to compare the performances of the multivariate exponentially weighted moving average (MEWMA) and the multivariate synthetic T2 control charts, for the case of a multivariate normally distributed process. A comparative study is made based on the average run length (ARL) performances of the control charts, using the simulation method, in order to identify the chart having the best performance in monitoring the process mean vector. The performances of the two charts, for different sample sizes and correlation coefficients, are presented in this paper. It was found that the MEWMA chart outperformed synthetic T2 chart for small shifts but the latter prevailed for moderate shifts. Both charts performed equally well for larger shifts. In addition, the performances of both MEWMA and synthetic T2 charts were found to be influenced by sample size and correlation coefficient. The two charts' performances improved as the sample size and correlation coefficient increased for small and moderate shifts, but the charts' performances did not depend on sample size and correlation coefficient when the shift was large.Average run length (ARL), MEWMA chart, multivariate synthetic chart, out-of-control, in-control
14
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(Downloads: 25)
Abstract (Viewed: 8)This study was conducted using crab shells as a biosorbent to remove Cu and Cd with different initial concentrations of 1, 5, 10, 15, and 20 mg/L in a biosorption treatment process. Crab shells were selected as biosorbents due to their abundance in the environment and ready availability as waste products from the market place. This study aimed to determine the ability of Scylla Serrata shells to remove Cu and Cd in an aqueous solution, as well as to provide a comparison of the removal rate between the two metals. The data were incorporated into hydrochemical software, PHREEQC, to investigate the chemical speciation distribution of each heavy metal. The shells of S. Serrata were found to have a significant (p<0.05) ability to remove Cu and Cd following the treatment. After six hours of treatment, the crab shells had removed 60 to 80% of both metals. However, the highest removal percentage was achieved for Cu with up to 94.7% removal rate in 5 mg/L initial Cu concentration, while 85.1% of Cd was removed in 1 mg/L initial solution, respectively. It can be concluded that the shells of S. Serrata could remove Cu and Cd better with significant results (p<0.05) in 1 and 5 mg/L initial concentrations, respectively.Biosorption, Cd, Cu, crab shell, PHREEQC
15
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(Downloads: 11)
Abstract (Viewed: 2)The source of gastrointestinal bleeding (GIB) remains uncertain in patients presenting without hematemesis. This paper aims at studying the accuracy, specificity and sensitivity of the Naive Bayesian Classifier (NBC) in identifying the source of GIB in the absence of hematemesis. Data of 325 patients admitted via the emergency department (ED) for GIB without hematemesis and who underwent confirmatory testing were analysed. Six attributes related to demography and their presenting signs were chosen. NBC was used to calculate the conditional probability of an individual being assigned to Upper Gastrointestinal bleeding (UGIB) or Lower Gastrointestinal bleeding (LGIB). High classification accuracy (87.3 %), specificity (0.85) and sensitivity (0.88) were achieved. NBC is a useful tool to support the identification of the source of gastrointestinal bleeding in patients without hematemesis.Bayesian network classifiers, Emergency department, hematemesis, upper gastrointestinal bleeding, Naive Bayes classifier, lower gastrointestinal bleeding, data mining
16
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(Downloads: 16)
Abstract (Viewed: 3)This study is an attempt to investigate the adsorption of petroleum hydrocarbon (toluene) from aqueous solutions using granular activated carbon (GAC) synthesized from oil palm shell (OPS) (referred as OPS based GAC). This study involved a series of batch experiments to determine the adsorption equilibrium and kinetics. The batch experiments were conducted by shaking 200 mL toluene solution containing 0.4 g GAC (initial concentrations of 5, 15, 25 and 30 mg/L) at 180 rpm at 30°C. The OPS-based GAC achieved more than 80% toluene removal in all the experiments. The adsorption capacity of the OPS based GAC estimated using Freundlich isotherm was 6.039 mg/g (L/mg) 1/n. The adsorption kinetic study showed that the adsorption of toluene was of chemisorption as the experimental data fitted better to the pseudo-second-order kinetic model than the pseudo-first-order kinetic model.Adsorption, equilibrium study, granular activated carbon, kinetics study
17
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(Downloads: 12)
Abstract (Viewed: 4)This case report highlights delay in the diagnosis of adenoma carcinoma of the lung in a female patient who has never smoked. It took three months to reach the diagnosis of stage IV lung carcinoma despite the presence of symptoms and an abnormal chest radiograph finding from the beginning. The clinical characteristics and predictors of missed opportunities for an early diagnosis of lung cancer are discussed. In this case, patient and doctor factors contributed to the delay in diagnosis. Thus, early suspicions of lung cancer in a woman with the presence of respiratory symptoms despite being a non-smoker are important in primary care setting.Adenocarcinoma, lung cancer, female, delay diagnosis, non-smoker
18
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(Downloads: 14)
Abstract (Viewed: 4)A major source of contemporary power is a Coal-fired Power Plant. These power plants have the capacity to continuously supply electricity to almost 500,000 residential and business units. An essential component of a Coal-fired Power plant is automation. A feature of this automation is an Intelligent System developed for the Power Plant. These Intelligent Systems have different configurations and design. This research studies the various Intelligent Monitoring Interfaces developed for Coal-fired Power Plant Trips, their advantages, disadvantages and proposes a new Intelligent Monitoring Interface that would alleviate the disadvantages of the existing systems. Current systems that use Neural Network models are investigated. The improved Intelligent Monitoring Interface as proposed in this paper is a modification of the existing monitoring system for the Coal-fired Power Plant Boiler Trips. It is expected to improve the overall system by implementing remote accessibility and interactability between the plant operator and the control system interface. The interface will also assist the operator by providing guidelines to troubleshoot the identified trips and the remote server application will allow data collected to be viewed anytime, anywhere.Component, Intelligent Systems, Neural Network, Coal-fired Power Plant Trips
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(Downloads: 13)
Abstract (Viewed: 3)In this paper, stormwater runoff from a residential catchment located in Miri, Sarawak, was characterized to determine the pollutant concentrations and loading. The observed average event mean concentrations were 116 mg/L for TSS, 115 mg/L for COD, 1.5 mg/L for NH3-N, and 0.23 mg/L for Pb. Based on Interim National Water Quality Standards (INWQS) for Malaysia, the average event mean concentration, EMC value for TSS exceeded class II (50 mg/L), exceeded class V (>100 mg/L) for COD, and exceeded class III (0.9 mg/L) for NH3-N. All four water quality parameters exhibited first flush characteristic but to varying magnitude which was influenced by the storm characteristics.Storm runoff, residential catchment, NPS pollutant
20
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(Downloads: 10)
Abstract (Viewed: 3)This paper presents a two-staged, pilot-scale vertical flow engineered wetland-based septage treatment system (VFEWs), which was designed and constructed in Curtin University Sarawak Campus to determine the system efficiency in treatment of septage. The treatment system consists of storage tanks, vertical ?ow wetlands, and a network of influent and effluent distribution pipes. The first stage of the VFEWs treatment system consists of three vertical flow wetlands placed in parallel to provide pre-treatment to raw septage to reduce solids and organic matters mainly by physical filtration and sedimentation processes. The percolate from the first stage is then further treated in the second stage, with four vertical flow wetlands, each with variation in operational regime and substrate (filter) type. The influences of various system and application-related parameters such as substrate material, presence of plants and plant types, and septage feeding practices (solid loading rate (SLR), batch and intermittent loading, and frequency of daily feeding) on pollutant removal efficiency were studied. Results from the first stage wetlands indicate that the removal of total solids and organic matter (BOD and COD) from the raw septage is promising (> 80%) at both SLR of 100 kg TS/m2.yr and 250 kg TS/m2.yr, respectively. However, a higher SLR decreased the average NH3-N removal efficiency. The findings on bed clogging assessment during the study period are also presented in this paper. Validation and expansion of these results are carried out with ongoing assessments on the system performance.Vertical-flow, engineered wetlands, septage, dewatering, substrate materials, plants, feeding regimes, removal efficiency;
21
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(Downloads: 14)
Abstract (Viewed: 4)The aim of this study is to investigate the effects of Palm Oil Clinker (POC) added as a stabilizer for improving the strength of peat. Cement and POC are added into peat up to 50% of the maximum dry unit weight. Treated peat achieved higher dry unit weight, almost 2.5 times as compared to untreated peat. Unconfined compressive strength (UCS) of treated peat is also investigated for soaked and unsoaked conditions. The results show that curing time improved the unconfined compressive strength of treated sample and increased by a factor of 20 and 11 for unsoaked and soaked conditions after 28 days of curing, respectively. The treated samples added with POC can be related to an increase in unconfined compressive strength for long time curing.Peat, Palm Oil Clinker (POC), Unconfined Compressive Strength (UCS)
22
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(Downloads: 15)
Abstract (Viewed: 2)Current ethanol production processes utilizing crops such as sugar cane and corn starch have been well established over the decade. Other crop such as cassava is a potential candidate in producing ethanol. However, thermal processes are required to hydrolyze starch for the production of fermentable sugars. The processes are energy intensive and could lead to undesirable by-products generation. In this work, the hydrolysis of cassava starch is studied following an experimental design as a statistical problem solving approach. Central composite design (CCD) is used in order to select the most important variables from the simultaneous study on the effect and influence of operating conditions of bioreactor utilized, namely, pH, temperature and substrate concentration, as well as to optimize the process of cassava starch hydrolysis. From the results obtained, it can be concluded that the cassava starch hydrolysis is enhanced by pH and temperature. Model validations show good agreement between experimental results and the predicted responses.Cassava, central composite design, hydrolysis, optimization, pH, temperature
23
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(Downloads: 7)
Abstract (Viewed: 5)The modelling of a three-dimensional (3-D) molten carbonate fuel cell (MCFC) was developed to study the effects of gas flow direction (co-flow and counter-flow) in anode and cathode on the generated power density by solving the mass and momentum conservation equations, electrochemical reaction and heat transfer. The simulation result of the co-flow temperature distribution was compared with the experimental data obtained from open literature. The molar fraction distribution of gases in the anode and cathode gas channels and temperature distribution across the cell were compared between two different flow directions. Furthermore, the performance of MCFC, which operates in the temperature range of 823 - 1023 K, was analysed by comparing the generated power density. The results showed that MCFC with co-flow attained higher power density compared to that of counter-flow at 873 K. However, at higher temperature of 1023 K, the generated power density was the same for both gas flow directions.Counter flow, Heat transfer, Molten Carbonate Fuel Cell, Numerical simulation, Three dimensional model

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