Conference Publications
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PublicationNumerical study of Fiber Reinforced Polymer Reinforced Normal Strength Concrete (FRPNSC) under hydrocarbon fire(IOP Publishing, 2020)Main safety requirements in concrete structural are the fire resistance requirements. One of the structural components is Fiber Reinforced Polymer Reinforced Normal Strength Concrete (FRPNSC). FRP reinforcement has been used as the replacement for conventional steel due to anti-corrosion and lightweight characteristics. Severe degradation on chemical bond properties for FRP will be effected when the temperature is rises. It is important to understand the minimum concrete cover thickness and concrete aggregates types to achieve fire resistance requirements. Standard fire equations are commonly used for fire simulations study. However, studies with hydrocarbon (HC) fire equations which fire ignited from petrochemical are limited. Therefore, in order to study the fire resistance of FRPNSC under hydrocarbon fire, temperature at the reinforcement needs to be predicted. In this study, explicit finite difference method (EFDM) used to solve the heat transfer model. The numerical algorithm of EFDM heat transfer model was constructed and used to analyse the concrete thickness and aggregates to achieve fire resistance requirement. The temperature result obtained by the EFDM model successfully validated with test data. FRPNSC under HC for carbonate aggregates give significant effect on the fire resistance compared to standard fire. The carbonate aggregates types also shows better fire performances compared to lightweight aggregates.
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PublicationAssessing the effect of different covariates distributions on parameter estimates for Multinomial Logistic Regression (MLR)(IOP Publishing, 2020)n fitting a multinomial logistic regression model, one of the most important part is estimating the parameter. In Multinomial Logistic Regression (MLR), Maximum Likelihood Estimation (MLE) method is used to estimate the parameters. MLE is the suitable method to be applied to the problems associated with categorical response variables since it has several benefits such as sufficiency, consistency, efficiency and parameterization invariance. This study investigates the different type of continuous distributions (normal, negatively skewed, positively skewed) on parameter estimation via Monte Carlo simulation. From the simulation result, it shows that as the sample size increases, the effect of covariate distribution reduces. The estimated parameter also less affected for model with normal covariate distribution. At sample size 300 and above, the estimated parameter with normal covariate distribution is considered as close to the true parameter value. Interestingly, for the positively skewed, the estimated parameter also obtained unbiased parameter at sample size 300 and above. However, for negatively skewed, it requires a larger sample size to get closer to the true parameter value. The estimated parameters deviate too far from the true parameter at small sample size. As expected, as sample size increases the parameter estimates for all distributions are getting close to the true parameter value. Lastly, the distribution for MLR with more than one covariate give the same effect as the MLR model with only one covariate on parameter estimations.
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PublicationNumerical simulation of non-newtonian blood flow through a tapered stenosed artery using the cross model(IOP Publishing Ltd., 2020)A Non-Newtonian model is used to examine the effect of tapering on the flow of blood along a stenosed artery which is caused by the pulsating nature the heart. The constitutive equation of the Cross model is used to capture the rheology of the streaming blood which accounts for the shear thinning behaviour of blood. The flow is considered to be laminar, incompressible, and axisymmetric. The finite- difference scheme was adopted to solve the non-linear equations describing the fluid motion in an unsteady two-dimensional case. The computation is presented in terms of the axial and radial velocities, volumetric flow rate, resistance to flow and the wall shear stress. The result from the numerical simulation clearly indicates that vessel tapering has considerable effect on the flow pattern of blood: as the tapering angle increases the flow rate and the axial velocity increases proportionately while the radial velocity, wall shear stress decreases and resistance to flow.
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PublicationNumerical study of Magnetohydrodynamic blood flow through an artery with multiple stenosis(IOP Publishing Ltd., 2020)The study theoretically accounts for the impact of Magnetohydrodynamics on streaming blood through an artery having multiple stenosis regions using the non-Newtonian Cross-rheological model. It is regarded that the streaming blood is unsteady and pulsative. The use of appropriate conditions is predicated on the assumption that the flow is laminar and axisymmetric which makes the problem two-dimensional. The geometry of stenosis was immobilized into a rectangular grid using the radial coordinate transformation. The finite difference scheme was employed for the numerical simulations. Specifically, magnetic field (Hartmann number), Reynolds number and severity of stenosis were varied over the entire arterial length. The results obtained predicted that increase in the Hartmann number and stenosis severity reduces the magnitude of the flow velocity, flow rate but the reverse is the case when the Reynolds number is increased. However, the wall shear stress and the resistance to flow are aided by increasing the Hartman number and the stenosis severity but reduces with increase in the Reynolds number. Hence, it is germane to apply the appropriate magnetic field in treatments otherwise, such patient may be vulnerable.
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