In recent years, carbon nanotubes have received widespread attention as promising carbon-based nanoelectronic devices. Due to their exceptional physical, chemical, and electrical properties, namely a high surface-to-volume ratio, their enhanced electron transfer properties, and their high thermal conductivity, carbon nanotubes can be used effectively as electrochemical sensors. The integration of carbon nanotubes with a functional group provides a good and solid support for the immobilization of enzymes. The determination of glucose levels using biosensors, particularly in the medical diagnostics and food industries, is gaining mass appeal. Glucose biosensors detect the glucose molecule by catalyzing glucose to gluconic acid and hydrogen peroxide in the presence of oxygen. This action provides high accuracy and a quick detection rate. In this paper, a single-wall carbon nanotube field-effect transistor biosensor for glucose detection is analytically modeled. In the proposed model, the glucose concentration is presented as a function of gate voltage. Subsequently, the proposed model is compared with existing experimental data. A good consensus between the model and the experimental data is reported. The simulated data demonstrate that the analytical model can be employed with an electrochemical glucose sensor to predict the behavior of the sensing mechanism in biosensors.
This paper is about the reduction of the overall size of metal blanking sheet that is being used to form a stamping product or car body panel of a car manufacturer in Malaysia. The current blanking sheet produces extra waste which will be recycled and does not contribute to increase productivity but increases inventory cost. The reduction in the blanking sheet size will lead to the reduction of raw material hence reduced the production cost. However, the reduced size of blanking sheet could affect the yield strength of the product. The study of the yield strength and yield improvement of the product are done by simulating stress analysis by using CATIA software. The results show that the new proposed size of the metal blanking sheet provides accuracy of the product dimension as well as maintaining the yield strength of the product and it reduced a significant amount of metal scrap which is nearly 4% of material weight and save around 10% of inventory cost.
Disease frequency is used to measure the situation of the disease with reference to the population size and time period
which is in a fractional form. The lower part of the fraction, known as denominator is the important part as it was used
to calculate a rate or ratio. Since the disease frequency is based on a ratio estimator, the results are highly dependent
upon the value of denominator. Therefore, the main aim of this paper was to propose a new method in calculating the
denominator for the relative risk equation with the application to chikungunya disease data from Malaysia. The new
method of calculating the denominator of the relative risk equation includes the use of discrete time-space stochastic
SIR-SI (susceptible-infective-recovered for human population and susceptible-infective for vector population) disease
transmission model instead of the total disease counts. The results of the analysis showed that the estimation of expected
disease counts based on total posterior means can overcome the problem of expected counts estimation based on the total
number of disease especially when there is no observed disease count in certain regions. The proposed new approach to
calculate the denominator for the relative risk equation is suitable for the case of rare disease in which it offers a better
method of expected disease counts estimation.
A poor Indoor Air Quality (IAQ) is a crucial problem which produces by the improper maintenance of Mechanical Ventilation and Air Conditioning (MVAC) ducting. A budget constraint intimidates for the practise of monitoring of the MVAC ducting. Thus IAQ measurements were conducted at the room where the air supplied by centralized air conditioning. It has been performed at four different offices that supply by two different Air Handling Unit (AHU). Walkthrough survey was conducted and the area samplings were selected for data collection. This paper examines the result of comparison of air ducting and air quality at academic office building, Universiti Tun Hussein Onn Malaysia (UTHM). The parameters involved were Temperature (°C), Relative Humidity (RH), Carbon Dioxide (CO2) and Carbon Monoxide (CO). Pictures were also captured to demonstrate the real conditions inside the ducting by using Mechanical Robot. Thus, duct cleaning was recommended to be an exceptional platform for the IAQ improvement.
In this paper, Taguchi experimental design technique was applied for optimization of chromium (Cr)/silver (Ag)/indium
tin oxide (ITO) SPR sensor for operation in near infrared region. Four factors were considered which include wavelength,
thickness of Cr, thickness of Ag, and thickness of ITO. Finite-difference-time-domain (FDTD) method was used in numerical
analysis for minimum reflectance (Rmin) and full-width-at-half-maximum (FWHM) performance parameters. The results
obtained from the Taguchi method shows that the optimized parameter for Rmin was 785 nm of wavelength, Cr (1 nm),
Ag (40 nm) and ITO (20 nm), whereas the optimized parameter for FWHM was 785 of wavelength, Cr (0 nm), Ag (40 nm)
and ITO (0 nm). In short, the optimum parameters for achieving the desired performance of sensor were successfully
predicted using Taguchi optimization method.
In this paper, we consider the system of Volterra-Fredholm integral equations
of the second kind (SVFI-2). We proposed fixed point method (FPM) to solve
SVFI-2 and improved fixed point method (IFPM) for solving the problem. In addition,
a few theorems and two new algorithms are introduced. They are supported by
numerical examples and simulations using Matlab. The results are reasonably good
when compared with the exact solutions.
Batu Reput’ is primary sediment mineral and abundantly found in Perlis. Perlis is one of the major producers of ‘Batu Reput’ in Malaysia that content large deposit of high-purity dolomite [CaMg (CO3)2]. Pure samples of ‘Batu Reput’ recently explored in the Koperasi Rimba Mas Padang Besar Quarry were investigated for their physical, chemical and mineralogical composition. SEM and XRD analysis methods were applied. The potential of ‘Batu Reput’ as a raw material in fertilizer production was investigated in this paper.
This paper studies about water obtained from fish pond of fisheries research centre. Usual water
quality parameters such as pH, COD, Turbidity and Ammonia content were analyzed before and
after irradiation. Electron beam irradiation was used to irradiate the water with the dose 100 kGy,
200 kGy and 300 kGy. Only high dose was applied on this water as only a limited amount of
samples was supplied. All the parameters indicated a slight increase after irradiation except for the
ammonia content, which showed a gradual decrease as irradiation dose increases. Sample
condition was changed before irradiation in order to obtain more effective results in the following
batch. The water sample from fisheries was diluted with distilled water to the ratio of 1:1.This was
followed with irradiation at 100 kGy, 200 kGy and 300 kGy. The results still showed an increase in
all parameters after irradiation except for ammonia content. For the following irradiation batch,
the pH of the sample was adjusted to pH 4 and pH 8 before irradiation. For this sample the
irradiation dose selected was only 100 kGy. A higher value of ammonia was observed for the
sample with pH 4 after irradiation. Other parameters were almost the same as the first two batches
The aim of this paper is to augment the existing literature on convergence of CO2 emissions, by adding carbon footprint per capita and ecological footprint per capita to the convergence debate. We use the residual augmented least squares regression to examine the stochastic convergence of the environmental indices in 27 OECD countries. Furthermore, in contrast to the previous studies which mainly used the conventional beta-convergence approach to examine conditional convergence, we use a beta-convergence method that is capable of identifying the actual number of countries that contribute to conditional convergence. The sigma-convergence of the environmental indices is also examined. The results suggest that conditional convergence exists in 12 countries for CO2 emissions per capita, 15 countries for carbon footprint per capita and also 13 countries for ecological footprint per capita. There is evidence for sigma-convergence for all the three indicators. The policy implications of the results are discussed in the body of the paper.
This paper provides a qualitative overview of different Optical Fiber Sensors (OFS),
which play important role in the field of sensors due to their excellent
characteristics, spontaneous response and easy handling system. The current
state of the art of optical fiber technology is reviewed, namely based on its main
characteristics and sensing advantages. In addition, the working principle of OFS
and their applications are discussed, particularly for sensor employment.
Soil properties are very crucial for civil engineers to differentiate one type of soil from another and to predict its mechanical behavior. However, it is not practical to measure soil properties at all the locations at a site. In this paper, an estimator is derived to estimate the unknown values for soil properties from locations where soil samples were not collected. The estimator is obtained by combining the concept of the ‘Inverse Distance Method’ into the technique of ‘Kriging’. The method of Lagrange Multipliers is applied in this paper. It is shown that the estimator derived in this paper is an unbiased estimator. The partiality of the estimator with respect to the true value is zero. Hence, the estimated value will be equal to the true value of the soil property. It is also shown that the variance between the estimator and the soil property is minimized. Hence, the distribution of this unbiased estimator with minimum variance spreads the least from the true value. With this characteristic of minimum variance unbiased estimator, a high accuracy estimation of soil property could be obtained.
In recent years, there are growing trends in using palm oil as raw materials in radiation curable resins production. In this study, the acrylated palm oil resins i.e. the EPOLA (epoxidized palm oil acrylate) and the POBUA (palm oil based urethane acrylate) were synthesized using two different systems, i.e. the 25 liter pilot scale reactor synthesis system and the 2 liter (L) laboratory scale reactor synthesis system through chemical processes known as acrylation and isocyanation. In this
paper, the property of the acrylated resins which were produced by these two systems were evaluated and compared between each other. Their properties were characterized using the Fourier transform infrared (FTIR) spectrophotometer for functional group identification; the gel permeation chromatography (GPC) for molecular weight (Mw) determination, the Brookfield viscometer for viscosity measurements, the acid values (AV) and the oxirane oxygen contents (OOC) analysis. As a result, the production process for both the 2 L and 25 L reactor system were found to be time consuming and the main advantages for the 25 L reactor was its higher productivity as compared with the 2 L reactor system with the same synthesis process parameters i.e. the temperatures and the experimental methods. Besides that, the 25 L reactor synthesis
process was found to be safe, easy to control and served unpolluted process to the environments. The final products, the acrylated palm oil resins were formulated into ultraviolet (UV) curable compounds before subjecting them under UVirradiation. As a result, the UV-curable palm oil resins showed potential uses as pressure sensitive adhesives, printing inks including overprint varnishes (OPV) and coatings.
The main goal of this paper was to study the effect of ultrasonic treatment time on the mechanical properties of thermoplastic natural rubber(TPNR) reinforced with hybrid MWNTs-OMMT. The intercalation of TPNR enhancement into layers of clay by increasing the d-spacing was found using X-ray diffraction. The tensile properties of nanocomposites treated with ultrasonic increased when compared with untreated nanocomposites. The optimum ultrasonic treatment time was obtained at 3 h. The transmission electron microscope micrograph showed a combination of intercalated-exfoliated structure of the TPNR composites with organic clay and dispersion of MWNTs. The ultrasonic treatment can promote the dispersion of MWNTs-OMMT in TPNR and also improved the compatibility of hybrid filler and the TPNR matrix.
In the organosolv pulping of the oil palm fronds, the influence of the operational variables of the pulping reactor (viz. cooking temperature and time, ethanol and NaOH concentration) on the properties of the resulting pulp (yield and kappa number) and paper sheets (tensile index and tear index) was investigated using a wavelet neural network model. The experimental results with error less than 0.0965 (in terms of MSE) were produced, and were then compared with those obtained from the response surface methodology. Performance assessment indicated that the neural network model possessed superior predictive ability than the polynomial model, since a very close agreement between the experimental and the predicted values was obtained.
Recovery of cellulose fibres from paper mill effluent has been studied using common polysaccharides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86mg/L of fibre and was most effective among the biopolymers. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed the highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was the most effective among the biopolymers. Response surface methodology was used to design all experiments, and an optimum operational setting was proposed. The test results indicate similar performance of alum and Guar gum in terms of floc settling velocities and sludge volume index. Since Guar gum is a plant derived natural substance, it is environmentally benign and offers a green treatment option to the paper mills for pulp recycling.
In this paper, two approaches were introduced to obtain Stackelberg solutions for two-level linear fractional programming problems with interval coefficients in the objective functions. The approaches were based on the Kth best method and the method for solving linear fractional programming problems with interval coefficients in the objective function. In the first approach, linear fractional programming with interval coefficients in the objective function and linear programming were utilized to obtain Stackelberg solution, but in the second approach only linear programming is used. Since a linear fractional programming with interval coefficients can be equivalently transformed into a linear programming, therefore both of approaches have same results. Numerical examples demonstrate the feasibility and effectiveness of the methods.
In this paper we determined the estimate of p-adic sizes of common zeros of partial derivative polynomials associated with a cubic form whose indicator diagrams have one overlapping segment by using Newton polyhedron technique. We showed that the p-adic sizes of such common zeros can be found explicitly on the overlapping segment of the indicator diagrams associated with the polynomials.
In this paper, we investigate the dynamical behavior in an M-dimensional nonlinear hyperchaotic model (M-NHM), where the occurrence of multistability can be observed. Four types of coexisting attractors including single limit cycle, cluster of limit cycles, single hyperchaotic attractor, and cluster of hyperchaotic attractors can be found, which are unusual behaviors in discrete chaotic systems. Furthermore, the coexistence of asymmetric and symmetric properties can be distinguished for a given set of parameters. In the endeavor of chaotification, this work introduces a simple controller on the M-NHM, which can add one more loop in each iteration, to overcome the chaos degradation in the multistability regions.
This work presents some comments concerning the paper entitled 'Lattice Boltzmann simulation of alumina-water nanofluid in a square cavity' by Yurong He, Cong Qi, Yanwei Hu, Bin Qin, Fengchen Li and Yulong Ding which was published in Nanoscale Research Letters in 2011. The comments are related to the numerical parameters and the computed results of average Nusselt number.
The present work reports the biobleaching effect on OPEFB pulp upon utilisation of extracellular xylano-pectinolytic enzymes simultaneously yielded from Bacillus amyloliquefaciens ADI2. The impacts of different doses, retention times, pH, and temperatures required for the pulp biobleaching process were delineated accordingly. Here, the OPEFB pulp was subjected to pre-treatment with xylano-pectinolytic enzymes generated from the same alkalo-thermotolerant isolate that yielded those of higher quality. Remarkable enhanced outcomes were observed across varying pulp attributes: for example, enzyme-treated pulp treated to chemical bleaching sequence generated improved brightness of 11.25%. This resulted in 11.25% of less chlorine or chemical consumption required for obtaining pulp with optical attributes identical to those generated via typical chemical bleaching processes. Ultimately, the reduced consumption of chlorine would minimise the organochlorine compounds found in an effluent, resulting in a lowered environmental effect of paper-making processes overall as a consequence. This will undoubtedly facilitate such environmentally-friendly technology incorporation in the paper pulp industry of today.