The effect of sintering temperature on silica derived from rice husk ash - Nickel Oxide (SiO 2 -NiO) foam fabrication via slurry technique

Fabrication of ceramic foam has been an interesting study in the field of a porous material due to the excellent mechanical and physical properties. This study presents an approach for the fabrication of Silica (SiO2) derived from rice husk ash (RHA) and Nickel Oxide (NiO) foams using the slurry technique, highlighting the sintering temperature affects. Polyvinyl alcohol (PVA) was used as binder and Polyurethane (PU) foam was applied as the space holder. The composition of SiO2 applied in this study was 20wt%. The PU foams dipped into SiO2-NiO slurry were dried and further sintered at three different sintering temperatures of 1050˚C, 1150˚C and 1250˚C. The morphologies of SiO2-NiO foams were observed by using the Scanning Electron Microscopy (SEM) and physical properties were determined by using Archimedes method for investigating the total porosity and bulk density. The identification of phases of SiO2-NiO foams were analysed by using X-Ray Diffraction (XRD). The XRD analyses indicated that there were only SiO2 and NiO present and no additional phases detected after sintering which implied the compatibility of SiO2 derived from RHA and NiO even temperatures up to 1250˚C. The density values of the SiO2-NiO foams were found to increase with increasing of sintering temperature. The densities were found to be in the range 0.5239g/cm³ to 0.6210g/cm3 and the percentage of the foams porosity were in the range of 69.71% to 75.19% .Thus it is concluded that the slurry technique is found to be successful to fabricate the SiO2 as derived from RHA and NiO foams. The sintering temperatures was found to affect the SiO2-NiO foams in turns of the density and porosity of the foam

Measurement of PCDD/Fs emissions from a coal–fired power plant in Malaysia and establishment of emission factors

AbstractThis paper presents the PCDD/Fs emissions measured from a coal–fired power plant in Malaysia. The study discusses partitioning of PCDD/Fs in particle and gas phase, effects of coal quality to PCDD/Fs formation, effects of air pollution control device (APCD) configuration to PCDD/Fs formation and establishment of emission factors of PCDD/Fs from the studied coal–fired power plant. The results presented in this study were mostly in good agreement with the previous works on PCDD/Fs emissions conducted in other countries. Laboratory analysis results showed that PCDFs were the dominant congeners. The emissions of PCDD/Fs were low which most probably due to the high combustion efficiency. The PCDFs/PCDDs ratio was more than 1 and PCDD/Fs were detected in fly ash, hence speculating that the formation of PCDD/Fs during coal combustion was mainly through de novo synthesis. Analysis on partitioning of PCDD/Fs showed that the compounds were mainly emitted in gas phase. This study also indicated that type of coal influenced the formation of PCDD/Fs during coal combustion where bituminous coal with high sulfur (S) content resulted in slightly lower PCDD/Fs emissions compared to sub–bituminous coal. It was also found that operation of flue gas desulfurization (FGD) reduced the emission of PCDD/Fs. The established emission factors for PCDD/Fs were in the range of 0.08 to 0.11ng I–TEQ/kg

Corporate bond rating changes, cross-market information transfer and the spillover effect in the United Kingdom

This PhD dissertation focuses on the bond rating changes assigned by S&P Corporation and Moody’s Corporation in the UK between 1997 and 2006. The main purpose of this research is to determine whether there is significant support for the private information hypothesis based on evidence of bond rating changes announcements and their impact drawn from this period. More specifically, the event study was implemented in order to examine the abnormal share performance during this period in the UK. There are five studies presented in this thesis. Based on a standardised cross-sectional parametric t-test, as proposed by Boehmer, Musumeci and Poulsen (1991), on 299 corporate bond rating changes announced by S&P and Moody’s, the first study shows that, based on sub-period analysis, no abnormal share return is detected in the UK. However, the rating downgrade announcements show significant negative market reaction. The second study examines the performance of the nonparametric test and parametric t-test in detecting any abnormal share performance during the period of the UK bond rating changes announcements. The nonparametric rank test was undertaken because of concern with the problem of non-normality and the unstable variance during the event. The results show that, based on downgrade announcements, the standardised cross-sectional parametric t-test outperforms the nonparametric tests that are based on the work of Corrado (1989) and Corrado and Truong (2008). Hence, the standardised cross-sectional parametric t-test is proved useful in overcoming the problem of event-induced variance. The third study compares the performance of four alternative return-generating models used in the event study. The market model is used as a performance benchmark against other models such as the quadratic model, the downside model and the higher order downside model in measuring the excess return of the share in the period of the corporate bond rating changes in the UK. The results indicate that there is enough evidence to support the existence of the private information effect during a rating downgrade but not a rating upgrade. The fourth study undertakes a comparison between reactions in Australia and the UK when S&P and Moody’s announced the bond rating revisions. In order to verify the result of share price reaction in developed capital markets in the period of the corporate bond rating changes announcements, an event study of 107 announcements of Australian bond rating changes is also carried out. In Australia, unlike the UK, significant share price reactions were observed in response to the upgrade and downgrade announcements. The fifth and the final study investigates the spillover effect on the foreign issuer’s local share price when the rating agency announced rating changes for corporate bonds issued by foreign issuers in the UK from 1997 to 2006. Based on 155 announcements of bond rating changes, there is enough evidence to confirm the existence of the spillover effect, found particularly during the rating downgrade announcements as shown by the combination sample (which includes all foreign issuers), Asia-Pacific and European companies

Familial and socio-environmental predictors of overweight and obesity among primary school children in Selangor and Kuala Lumpur.

Introduction: A cross-sectional study was conducted to determine the familial and socio-environmental predictors of overweight and obesity among 1430, 9-12 year-old primary school children and their parents in Selangor and Kuala Lumpur. Methodology: Body weight and height were measured and body mass index was calculated. Modified Child Feeding (CFQ) and Determinants of Adolescent Social Well-being and Health (DASH) questionnaires were used to measure familial and socio-environmental factors. Results: A total of 17.9% of the children were overweight while 16.0% were obese. Positive relationships were found between child’s BMI and parent’s BMI (r = 0.129, p < 0.01), concern about child’s weight (r = 0.125, p < 0.01) and restriction (r = 0.057, p < 0.05) to unhealthy foods. However, negative relationships were found between child’s BMI with pressure to eat (r = -0.135, p < 0.01) and neighbourhood safety perception (r = -0.053, p < 0.05). The logistic regression analysis showed that being male (Exp(β) = 0.538; 95% CI = 0.421-0.687), higher parent’s BMI (Exp (β) = 1.055; 95% CI = 1.028-1.082), higher concern about child’s weight (Exp (β) = 1.082; 95% CI = 1.030-1.127), low pressure to eat (Exp (β) = 0.857; 95% CI = 0.801-0.916) and low perception of neighbourhood safety (Exp (β) = 0.951; 95% CI = 0.913-0.990) were significantly associated with increased risk of overweight. Conclusion: Parents should be the main target for education to modify children’s weight status. Further research should be carried out to understand the mechanism of influence of parents and the socio-environment on child’s health

Factors Associated With Body Weight Status of Iranian Postgraduate Students in University of Putra Malaysia

Background: Good nutrition, a balanced diet and regular physical activity are foundations of good health. Research has found that dietary patterns change dramatically following the arrival of students in a foreign country. However, nutritional status of Iranian students studying oversea has never been investigated. Objectives: The objective of this study was to determine factors associated with body weight status of Iranian postgraduate students in Universiti of Putra Malaysia (UPM). Materials and Methods: A cross-sectional study was conducted to determine the body weight status of 210 Iranian postgraduate students aged between 22 and 55 years in University of Putra Malaysia. The associations between body weight status and socio demographics factors and also lifestyle factors (smoking and physical activity) were assessed. Anthropometric factors (height, weight, BMI and waist and hip circumferences) were measured. Chi-square, Spearman Rho and Pearson tests were used for data analysis. Results: From a total of 210 postgraduate students 110 were females, and 100 males. No significant correlation was observed between smoking and BMI (P = 0.4). However, statistically significant correlations were observed between gender (P = 0.007), physical activity (P = 0.02), using protein (P = 0.005), carbohydrate (P = 0.002), fat (P = 0.001), fiber (P = 0.003), vitamin C (P = 0.04), calcium (P = 0.005), waist circumference (P = 0.02), hip circumference (P = 0.001), Waist to Hip Ratio (P = 0.002), and BMI. Conclusions: The nutritional behavior of university students was poor. Therefore, it is essential to encourage young people, including university students to enrich their diets with milk, beans, fruit, and vegetables to decrease the risks of nutrition related disorders

Intelligence quotient and perceptual ability: an inter-relationship based on brainwave power ratio features

Cognitive ability refers to the characteristic approach by the brain in processing information. These can be observed through various aspects of cognition such as intelligence and perceptual ability. Studies have shown that both mental constituents originate from the same neurological substrate in the prefrontal cortex. Hence, the paper discusses the relationship between intelligence and perceptual ability using electroencephalogram (EEG) features. The study is based on resting brainwave of fifty samples and focused on the left and right prefrontal cortex. The intelligence quotient (IQ) scores obtained are then used to establish the control groups. Subsequently, the pattern of alpha and theta power ratio for each IQ level is observed and successfully correlated with perceptual ability through the Neural Efficiency Hypothesis of intelligence.Keywords: EEG; intelligence; IQ; perceptual ability; power ratio

Back calculation Anti Windup PID controller on Several Well-Known Tuning Method for Glycerin Bleaching Process Temperature Regulation

The aim of this paper is to comprehend the performance of back calculation anti windup scheme with difference tracking time constant, Ta on Proportional &ndash; Integral - Derivative (PID) controller for improving temperature regulation of glycerin bleaching process.&nbsp; Several available well tuning methods including Ziegler Nichols (ZN), Internal Model Control (IMC) and Integral Square Error (ISE)-Load are used and analyzed. The performance of the controller tuning methods are&nbsp; compared based on percentage of overshoot, settling time, rise time and time to recovery on the presence of disturbance. From the results, the best performance of temperature regulation for glycerin bleaching process can be reached by using ISE-Load tuning with tracking time constant, Ta equal to derivative time constant, Td.&nbsp

Evaluation of electromagnetics radiation for stroke patients and non-stroke participants according to body segmentation

This research evaluates the electromagnetic radiation (EMR) for the stroke patients and non-stroke patients according to body segmentation. The human body is divided into three segments: top, middle and bottom. The frequency in hertz is collected at 23 points around the human body namely left side, right side and chakra points from 199 subjects undergoing post-stroke treatment and 100 non-stroke participants. The EMR is captured using frequency detector equipped with a dipole antenna. The data is collected by taking the reading of the frequency 5 times at each point at the same location; hence, the average value is calculated. The statistical analysis of the EMR are examined using SPSS software and Microsoft excel is used to calculate the average frequency of the data. In conclusion, the findings significantly shows that stroke patients has lower frequency value of EMR for both right side and left side but has higher frequency for chakra system. This is true for all the three segments of the body. Furthermore, it is also shown that there is no correlation between the left and the right side frequency for the stroke patients whereas the left-right correlation values are significantly high for the non-stroke participants. This observation justify that EMR from human body can contribute to early detection for stroke

Evaluation of Varies Model Order in GA-Optimized Parameter Estimation of Toothbrush Rig System

Parameter estimation is a vital part in constructing the best model of a dynamic system. This paper analyzed the performance of toothbrush rig parameter estimation using different model orders. Parameter estimation process of the system is performed through system identification. The approximate mathematical model that resemble the real system is obtained when the output is measured after loading the input signal. The application of real-coded genetic algorithm (RCGA) is proposed as optimization method in estimating the parameters of dynamic system. The best model is obtained by optimizing the objective function of mean squared errors. The performance is analyzed to get the approximate model of the real system using three different model orders with 10 times analysis for each model. A few criteria have been considered which are the optimization result of objective function, time execution and validation process. Real- coded genetic algorithm indicates that parameter estimation with model order 3 is chosen as the best model or the dynamic system as it has the highest performance compared to others

Escherichia coli growth modeling using neural network

The assessment of water microbial quality is normally performed by verification ofEscherichia coli where the growth is in nonlinearity. NARX is computational tools that haveextensive utilization in solving nonlinear time series problems. It is well known as one of thetechnique that has the ability to predict with efficient and good performance. Using NARX, ahighly accurate model was developed to predict the growth of Escherichia coli (E. coli) basedon pH water parameter. The multiparameter portable sensor and spectrophotometer data wereused to build and train the neural network. The selection of neural network structure for pHand optical density modelling was optimized and also the training and validation wereanalyzed. The result exhibited that NARX modelling was able to predict the growth of E. colibased on pH water parameter with overall regression is 0.99956.Keywords: neural network; NARX; prediction; Escherichia coli; pH; optical density