Wan Mohd Faizal Wan Ab Rahim
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Preferred name
Wan Mohd Faizal Wan Ab Rahim
Official Name
Wan Mohd Faizal, Wan Ab Rahim
Alternative Name
Faizal, Wan Mohd
Rahim, W. M.Faizal W.A.
Rahim, Wan Mohd Faizal Wan Abd
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Scopus Author ID
58104583100
Researcher ID
Q-5320-2017

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Computational Fluid Dynamics Analysis of Varied Cross-Sectional Areas in Sleep Apnea Individuals across Diverse Situations

2024-01-01 , Wan Mohd Faizal Wan Ab Rahim , Khor Chu Yee , Mohamad Suhaimi Shahrin , Muhamad Nur Misbah , Mohd. Hazwan Mohd. Hanid , Masniezam Ahmad , Mohd Haidiezul Jamal Ab Hadi

Obstructive sleep apnea (OSA) is a common medical condition that impacts a significant portion of the population. To better understand this condition, research has been conducted on inhaling and exhaling breathing airflow parameters in patients with obstructive sleep apnea. A steady-state Reynolds-averaged Navier–Stokes (RANS) approach and an SST turbulence model have been utilized to simulate the upper airway airflow. A 3D airway model has been created using advanced software such as the Materialize Interactive Medical Image Control System (MIMICS) and ANSYS. The aim of the research was to fill this gap by conducting a detailed computational fluid dynamics (CFD) analysis to investigate the influence of cross-sectional areas on airflow characteristics during inhale and exhale breathing in OSA patients. The lack of detailed understanding of how the cross-sectional area of the airways affects OSA patients and the airflow dynamics in the upper airway is the primary problem addressed by this research. The simulations revealed that the cross-sectional area of the airway has a notable impact on velocity, Reynolds number, and turbulent kinetic energy (TKE). TKE, which measures turbulence flow in different breathing scenarios among patients, could potentially be utilized to assess the severity of obstructive sleep apnea (OSA). This research found a vital correlation between maximum pharyngeal turbulent kinetic energy (TKE) and cross-sectional areas in OSA patients, with a variance of 29.47%. Reduced cross-sectional area may result in a significant TKE rise of roughly 10.28% during inspiration and 10.18% during expiration.

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Computational fluid dynamics modelling of human upper airway: A review

2020-11-01 , Wan Mohd Faizal Wan Ab Rahim , Ghazali N.N.N. , Khor Chu Yee , Badruddin I.A. , Zainon M.Z. , Yazid A.A. , Ibrahim N.B. , Razi R.M.

Background and objective: Human upper airway (HUA) has been widely investigated by many researchers covering various aspects, such as the effects of geometrical parameters on the pressure, velocity and airflow characteristics. Clinically significant obstruction can develop anywhere throughout the upper airway, leading to asphyxia and death; this is where recognition and treatment are essential and lifesaving. The availability of advanced computer, either hardware or software, and rapid development in numerical method have encouraged researchers to simulate the airflow characteristics and properties of HUA by using various patient conditions at different ranges of geometry and operating conditions. Computational fluid dynamics (CFD) has emerged as an efficient alternative tool to understand the airflow of HUA and in preparing patients to undergo surgery. The main objective of this article is to review the literature that deals with the CFD approach and modeling in analyzing HUA. Methods: This review article discusses the experimental and computational methods in the study of HUA. The discussion includes computational fluid dynamics approach and steps involved in the modeling used to investigate the flow characteristics of HUA. From inception to May 2020, databases of PubMed, Embase, Scopus, the Cochrane Library, BioMed Central, and Web of Science have been utilized to conduct a thorough investigation of the literature. There had been no language restrictions in publication and study design of the database searches. A total of 117 articles relevant to the topic under investigation were thoroughly and critically reviewed to give a clear information about the subject. The article summarizes the review in the form of method of studying the HUA, CFD approach in HUA, and the application of CFD for predicting HUA obstacle, including the type of CFD commercial software are used in this research area. Results: This review found that the human upper airway was well studied through the application of computational fluid dynamics, which had considerably enhanced the understanding of flow in HUA. In addition, it assisted in making strategic and reasonable decision regarding the adoption of treatment methods in clinical settings. The literature suggests that most studies were related to HUA simulation that considerably focused on the aspects of fluid dynamics. However, there is a literature gap in obtaining information on the effects of fluid-structure interaction (FSI). The application of FSI in HUA is still limited in the literature; as such, this could be a potential area for future researchers. Furthermore, majority of researchers present the findings of their work through the mechanism of airflow, such as that of velocity, pressure, and shear stress. This includes the use of Navier–Stokes equation via CFD to help visualize the actual mechanism of the airflow. The above-mentioned technique expresses the turbulent kinetic energy (TKE) in its result to demonstrate the real mechanism of the airflow. Apart from that, key result such as wall shear stress (WSS) can be revealed via turbulent kinetic energy (TKE) and turbulent energy dissipation (TED), where it can be suggestive of wall injury and collapsibility tissue to the HUA.

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Computational fluid dynamics analysis on overweight sleep APNEA patient under various breathing flow patterns

2023 , Muhammad Nooramin Che Yaakob , Wan Mohd Faizal Wan Ab Rahim , Khor Chu Yee

Obstructive Sleep Apnea (OSA) is a breathing disorder that occurs during sleep. This syndrome affects numerous people, especially those with abnormal body fat composition parameters such as body mass index (BMI) of more than 25 kg/m2 (overweight & obesity). OSA ensues when the tongue and soft palate muscles in a relaxed condition move towards gravity when the patient is in a supine position; this causes narrowing and blockage on the upper airway affecting breathing. There are several treatments for OSA, including upper airway surgery. A better understanding of airflow characteristics will assist ENT surgeons in identifying the blockage area. This paper examines airflow characteristics of the upper airway for overweight sleep apnea patients. The narrow and blockage area on the respiratory tract causes turbulence formation that is evaluated using Computational Fluid Dynamic (CFD) based on an actual parameter of the 3D model obtained by CT scan image result. Reynold’s averaged Navier-Stoke (RANS) equation and turbulent model, k-ω shear stress transport (SST), were applied. Airflow fluctuation was characterized by crucial parameters such as velocity, pressure, and turbulent kinetic energy (TKE). The result shows that the narrow cross-sectional area of the airway causes accretion of the velocity and pressure in the pharyngeal airway. The increasing airflow parameter results in high turbulent kinetic energy (TKE) that will determine the severity level of OSA patients. Investigating airflow characteristics in overweight OSA patients will help the medical practitioner validate the narrow and blockage area for the surgery.

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Effect of zinc addition on the performance of aluminium alloy sacrificial anode for marine application

2017-09-26 , Khan B. , Rosli M.U. , Hazrin Jahidi Jaafar , Muhammad Ikman Ishak , Muhammad Syamil Zakaria , Mohd Riduan Jamalludin , Khor Chu Yee , Wan Mohd Faizal Wan Ab Rahim , Rahim W.M. , Mohd Al-Hafiz Mohd Nawi

In this work, the effect of zinc addition on the performance of aluminum-based sacrificial anode in seawater was investigated. The parameters used in assessing the performance of the cast anodes are anodic efficiency, protection efficiency and polarized potential. The content of zinc in the anodes was varied after die casting. The alloys produced were tested as sacrificial anode for the protection of mild steel for marine application at room temperature. Factors such as reactivity of zinc particles in the seawater, corrosion activity during the period of experiment, pH of seawater and the electronegativity potential of zinc were collected for analysis. Overall findings shows addition of zinc increases rate of corrosion to the sacrificial anode and the protection offered by the sacrificial anodes measured and collected in PIT shows the seawater react to sacrificial anode and no porosity reaction between the anodes. The microstructure showed the intermetallic structures of β-phase which breakdown the alumina passive film, thus enhancing the anode efficiency.

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Charging strategy in electric vehicle chargers by utilizing demand side management scheme

2023 , Aziah Khamis , M.H. Aiman , Wan Mohd Faizal Wan Ab Rahim , Khor Chu Yee

Electric vehicles (EVs) have received significant attention recently, given their potential technical, environmental, and economic benefits. However, given the fact that EV charging could happen at peak demand. This situation may deteriorate the distribution network's overall performance, particularly in terms of voltage stability. The novelty of this paper is to evaluate the impacts of the integration of EV chargers in the distribution network and to propose a charging strategy in EV chargers. The proposed charging strategy manages the power in the distribution network during the EV charger connection by utilizing demand side management. The IEEE 9-bus radial distribution system was used as the test network. Four scenarios were conducted by relevant assessments using the deterministic and probabilistic approaches. The result showed the influence of charging strategy on EV charging systems where it can reduce the impact of integration EV chargers by shifting the load of EV charging from the on-peak period to the off-peak period. As a result of using EV charging strategy, peak active power losses were reduced by 2.2 to 3.2 percent. The proposed method contributes the idea to the engineer and researcher in designing the EV charging strategy. However, the charging EV strategy could be further improved by optimizing the value of the relay setting of both the UVLS relay and the power demand relay in future research.

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