A NOVEL CELL BY CELL ARTIFICIAL NEURAL NETWORKS APPROACH FOR PREDICTING THE TEMPERATURE OF STEADY STATE, INCOMPRESSIBLE, LAMINAR FLOWS

A cell-by-cell artificial neural network approach is used to predict the temperature field of steady-state, incompressible, laminar flows in a two-dimensional computational domain. The temperature field is characterized by the initial flow velocity, fluid temperature and the temperature of the wall boundaries. Two types of neural network architectures are developed in this research, namely cascade-forward and feedforward models. Both models are trained using Levenberg-Marquardt and Bayesian regularization backpropagation algorithms. The training data for the models are obtained by solving the Navier-Stokes equations for steady-state, incompressible, heat conducting laminar flow in two-dimensional domain using commercial ANSYS Fluent software. The results show that the predicted values produced by the ANN models are in good agreement with the CFD simulation data. Even though the introduction of artificial neural networks at the cell level increases the complexity of the training process, this drawback is compensated by the increase in flexibility (generality) of the models. More importantly, the results show that the cell-by-cell artificial neural network approach is capable of providing an accurate prediction of the temperature field for the fluid flow investigated in this research, as indicated by the statistical indices used to evaluate the performance of prediction models. The feedforward ANN model trained using the Bayesian regularization backpropagation algorithm gives the most accurate predictions among all models

Numerical modelling of blood cells distribution in flow through cerebral artery aneurysm

Recent aneurysm studies have focused on the correlation between different parameters and rupture risk; however, there have been conflicting findings. Computational fluid dynamics (CFD) allows for better visualization but idealized aneurysm models may neglect important variables such as aneurysm shape and blood flow conditions. In this paper, one case of an aneurysm was studied with CFD using a non-Newtonian Power Law Model to investigate the correlation between wall shear stress and blood cells distribution. Results show that velocity of blood flow decreased as it entered the aneurysm and the neck of the aneurysm experienced a greater magnitude of wall shear stress than the remainder of the cerebral artery. Besides, the blood cells generally begin at low velocities and increase after the first curve of the artery. Findings and further studies with larger cases of patients will improve treatment and prevention of aneurysm ruptures

Investigation of the Head Impact Power of a Sepak Takraw Ball on Sepak Takraw Players

Sepak takraw is a traditional sport in Asia in which the players use various parts of their bodies to hit the ball, with the exception of their hands. Unlike other sports such as soccer, boxing, and rugby, it is observed that none of the studies in the literature have examined the injuries resulting from the impact of the sepak takraw ball on the players’ heads during a game. This study was initiated following the incidents of the 24th SEA Games in Korat, Thailand, in year 2007, whereby a number of players from the Malaysian Sepak Takraw Association (PSM) had to withdraw themselves from the championship. These players suffered from headaches which were believed to be caused by the impact of the sepak takraw ball, considering the fact that heading is one of the basic movements used to hit the ball. Moreover, it is expected that the sepak takraw ball travels at high velocities during the game. Hence, the objective of this study is to investigate the impact of the sepak takraw ball and its corresponding level of head injury among sepak takraw players in Malaysia by means of numerical simulations and experiments. In order to achieve this objective, a model of the scalp, skull, cerebrospinal fluid and brain is first developed and simulations are then carried out using finite element analysis (FEA) software. The results show that the maximum speed of the sepak takraw ball before heading is 13.581 m/s while the maximum impact force on the head obtained from the simulations is 688.11 N. The maximum displacement and maximum linear acceleration of the brain’s centre of gravity is found to be 0.0080 m and 1674.5 m/s2, respectively, while the head impact power (HIP) is determined to be 11.366 kW. According to Newman et al. (2000), the probability of concussion is 39% and based on the results obtained in this study, it can be concluded that the players may suffer from mild traumatic brain injuries (MTBI) due to the high impact of the sepak takraw ball during heading. Hence, it is recommended that the players wear protective headbands to reduce the impact during heading and prevent the occurrence of MTBI in the long term

APPLICATION OF INTEGRATED SUSTAINABILITY ASSESSMENT: CASE STUDY OF A SCREW DESIGN

Sustainability can be referred to as meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. For politicians, it is an attempt to shape the social; sustain the economy and preserved the environment for future generations. Balancing these three criteria is a difficult task since it involves different output measurements t. The aim of this paper is to present a new approach of evaluating sustainability at the product design stage. There are three criteria involved in this study which is manufacturing costs, carbon emission release into the air and ergonomic assessment. Analytic hierarchy process (AHP) is used to generalize the outputs of the three criteria which is then ranked accordingly. The highest score is selected as the best solution. In this paper, a simple screw design is presented as a case study

Wall Shear Stress Prediction Using Computational Simulation on Patient Specific Artery with Aneurysm

An aneurysm is formed when a blood vessel becomes dilated or distorted. It will cause the vessel to expand to a size greater than its original diameter. In this study, Wall Shear Stress (WSS) of cerebral artery with aneurysm was predicted using Computational Fluid Dynamics (CFD). WSS in the artery is one of the indicators for brain artery disease progression. Based on the results, the maximum value of blood velocity and WSS on patient specific artery with aneurysm are 3.23 m/s and 60.1 Pa, respectively. The location of high WSS is before and after the aneurysm bulge. The WSS is above the normal physiological value where the artery wall is exposed to high stress. Hence, the vessel at this location is anticipated to become weaker and could be further dilated

Wall Shear Stress Prediction Using Computational Simulation on Patient Specific Artery with Aneurysm

An aneurysm is formed when a blood vessel becomes dilated or distorted. It will cause the vessel to expand to a size greater than its original diameter. In this study, Wall Shear Stress (WSS) of cerebral artery with aneurysm was predicted using Computational Fluid Dynamics (CFD). WSS in the artery is one of the indicators for brain artery disease progression. Based on the results, the maximum value of blood velocity and WSS on patient specific artery with aneurysm are 3.23 m/s and 60.1 Pa, respectively. The location of high WSS is before and after the aneurysm bulge. The WSS is above the normal physiological value where the artery wall is exposed to high stress. Hence, the vessel at this location is anticipated to become weaker and could be further dilated

Thin and sharp edges bodies-fluid interaction simulation using cut-cell immersed boundary method

This study aims to develop an adaptive mesh refinement (AMR) algorithm combined with Cut-Cell IBM using two-stage pressure–velocity corrections for thin-object FSI problems. To achieve the objective of this study, the AMR-immersed boundary method (AMR-IBM) algorithm discretizes and solves the equations of motion for the flow that involves rigid thin structures boundary layer at the interface between the structure and the fluid. The body forces are computed in proportion to the fraction of the solid volume in the IBM fluid cells to incorporate fluid and solid motions into the boundary. The corrections of the velocity and pressure is determined by using a novel simplified marker and cell scheme. The new developed AMR-IBM algorithm is validated using a benchmark data of fluid past a cylinder and the results show that there is good agreement under laminar flow. Simulations are conducted for three test cases with the purpose of demonstration the accuracy of the AMR-IBM algorithm. The validation confirms the robustness of the new algorithms in simulating flow characteristics in the boundary layers of thin structures. The algorithm is performed on a staggered grid to simulate the fluid flow around thin object and determine the computational cost.Validerad;2019;Nivå 2;2019-08-13 (johcin)</p

Blood flow acoustics in carotid artery

This paper aims to identify and study the blood flow and acoustics characteristics of different degrees of stenosis in the carotid artery. Blood flow will produce acoustics, but the presence of different levels of stenosis are expected to produce different acoustic characteristics. The blood flow and acoustic characteristics are simulated by using computational fluid dynamics software (CFD). Several three-dimensional models of carotid arteries that have different degrees of stenosis are used together with a normal/healthy carotid artery - i.e., 30% and 70% degrees of blockage. The geometry of 30% and 70% stenosed model are computationally generated from a normal carotid artery geometry. In addition, the blood viscosity level was also increased in this study to a value of 0.005 kgms-1 (from the normal viscosity of 0.004 kgms-1) to compare the effect of hyperglycaemia (i.e., diabetes mellitus) that may bring additional complications to blood flow. Pulsatile simulations are used for all cases in order to mimic the exact blood flow condition in which the inlet velocity and outlet pressure change with time. The present study shows that as the degree of stenosis increases at the common carotid artery (CCA), the velocity at the internal carotid artery (ICA) and external carotid artery (ECA) outlet increases. The maximum velocity changes for ICA at the systolic peak from normal to 70% degree of stenosis for carotid artery shows an increase by 8%, while an opposite trend is observed for the maximum velocity changes of ECA at the systolic peak, where a reduction by 3% occurs from normal to 70% degree of stenosis for carotid artery. In terms of viscosity, as the viscosity of the blood increases, the velocity of the blood flow decreases in all geometry carotid arteries and may potentially provide further complications on clinical problems. The acoustic simulation showed that the acoustic power increases by 5% and 20% for carotid artery geometry that has 30% and 70% degree of stenosis, respectively. The present study indicates potential for further developing non-invasive acoustic means to diagnose and measure stenosis in carotid arteries

Proceedings of International Technical Postgraduate Conference 2022

This conference proceedings contains articles on the various research ideas of the academic &amp; research communities presented at the International Technical Postgraduate Conference 2022 (TECH POST 2022) that was held at Universiti Malaya, Kuala Lumpur, Malaysia on 24-25 September 2022. TECH POST 2022 was organized by the Faculty of Engineering, Universiti Malaya. The theme of the conference is “Embracing Innovative Engineering Technologies Towards a Sustainable Future”.  TECH POST 2022 conference is intended to foster the dissemination of state-of-the-art research from five main disciplines of Engineering: Electrical Engineering, Biomedical Engineering, Civil Engineering, Mechanical Engineering, and Chemical Engineering. The objectives of TECH POST 2022 are to bring together innovative researchers from all engineering disciplines to a common forum, promote R&amp;D activities in Engineering, and promote the dissemination of scientific knowledge and research know-how between researchers, engineers, and students. Conference Title: International Technical Postgraduate Conference 2022Conference Acronym: TECH POST 2022Conference Date: 24-25 September 2022Conference Location: Faculty of Engineering, Universiti Malaya, Kuala Lumpur Malaysia (Hybrid Mode)Conference Organizers: Faculty of Engineering, Universiti Malaya, Kuala Lumpur, Malaysia