Mohd Afendi Rojan
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Preferred name
Mohd Afendi Rojan
Official Name
Mohd Afendi , Rojan
Alternative Name
Afendi, Mohd
Rojan, M. Afendi
Afendi Rojan, M.
Afendy, M.
Rojan, M. A.
Mohd Afendi, R.
Afendi, M.
Main Affiliation
Scopus Author ID
57188766103
Researcher ID
GQR-0248-2022

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  • Publication
    Study of eddy current density distribution in a contactless breast cancer detection mechanism using magnetic induction spectroscopy
    ( 2017-01-01)
    Gowry Balasena
    ;
    Shahriman Abu Bakar
    ;
    Zulkarnay Zakaria
    ;
    Ryojun Ikeura
    ;
    Zuradzman Mohamad Razlan
    ;
    Hazry Desa
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Cheng Ee Meng
    ;
    Mohd Afendi Rojan
    Breast cancer is a throbbing disease that no longer needs an introduction. This is especially true among women due to their unique breast structure that naturally has more breast tissues compared to that of man’s. It is been forecasted that in 2015, a minimum of 60290 new cases of breast cancer will be reported. The goal of this study is to analytically evaluate the changes in the induced Eddy current densities as a function of di-electrical properties of the breast tissue with respect to tumor positioning as well as its size. This is achieved by running numerical simulations on the proposed mechanism of magnetic induction to detect tumors among healthy breast tissue via a 2D breast model configuration. The analytical results presented in this article, proved that the multi frequency magnetic induction principle is viable in detecting the breast lesions as small as 0.2 cm non-invasively through the distributions of the induced Eddy current density. While important pattern of the induced current were reflected when the tumors are located at the far ends of the breast diameter. The minimum results computational time with the proposed system is 10 s.
  • Publication
    Approach to enhance the heat transfer of valve seats through thermal analysis
    ( 2022-02-05)
    Hassan M.A.S.M.
    ;
    Zuradzman Mohamad Razlan
    ;
    Shahriman Abu Bakar
    ;
    Mohd Afendi Rojan
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Ibrahim Z.
    ;
    Ishak A.A.
    ;
    Rahman A.A.
    ;
    Mohd Ridzuan Mohd Jamir
    The valve seat insert is a component of the engine cylinder head, whose primary function is to seal the combustion chamber and absorb the valve's heat, releasing it to the engine cylinder head. The valves experience high temperatures owing to high thermal loading and low heat absorption in the valve seat, which can potentially damage the engine. Therefore, the thermal characteristics of the valve seat must be optimised to increase the heat transmission between the valve and its seat. Here, three copper alloy valve seats, brass, beryllium copper, and bronze copper, were tested against the existing sintered iron valve seat, and their temperature maps were determined using actual engine operation conditions. The instantaneous heat transfer coefficients of the valves, seats, and engine cylinder head during the four-stroke cycle were evaluated using a one-dimensional thermal simulation analysis. The values obtained were used to assess the finite-element model using a three-dimensional thermal simulation in the Ansys software. The results show that the brass, beryllium-, and bronze-copper valve seats increased the overall heat flux by 4.46%, 4.16%, and 2.06%, respectively, compared to those for sintered iron. Thus, the results are essential to improve the thermal characteristics of the copper alloy valve seat imposed on the cylinder head. For validation, an experimental engine thermal survey and uncertainty magnification factors were used to validate the model. The results indicate that the maximum difference between the simulation and experimental values is 8.42%. Therefore, this approach offers a direct and comprehensible application for evaluating the temperature distribution, heat gradient, and heat flux of the cylinder head of air-cooled spark-ignition moped motorcycle engines using copper alloy valve seat materials at intermediate engine speeds. Furthermore, this method is applicable as a platform for the automotive industry to improve the heat transfer of the structural parts of internal combustion engines.
  • Publication
    Microwave reflection measurement on thermal degradation of animal and vegetable oils
    ( 2022-10-01)
    Cheng Ee Meng
    ;
    Shahriman Abu Bakar
    ;
    Tan W.H.
    ;
    Mohd Afendi Rojan
    ;
    Khor Shing Fhan
    ;
    Nashrul Fazli Mohd Nasir
    ;
    Robiah M.C.W.S.
    ;
    You K.Y.
    In this work, the reflection measurement on animal and vegetable oils due to different heating temperature was conducted using Agilent E8362B slim probe in conjunction with Agilent E8362B PNA Network Analyzer. The effect of thermal degradation on measured reflection efficient (Γ) is investigated. Many chemical processes are occurred when edible oils are heated during frying process. The thermal degradation products, i.e., volatile and non-volatile chemical compounds are generated. The generated volatile chemical compounds are dangerous to human health. Products of thermal degradation of animal and vegetable oils can be carcinogenic. On the other hand, it may cause diabetes, atherosclerosis, Alzheimer’s and Parkinson’s diseases, coronary heart disease, sudden cardiac death, and systemic vasculitis. Slim probe and open ended coaxial sensor are implemented to measure the reflection coefficient of the cooking oils. The fresh animal fats and vegetable oils are commercially available in local market. Five types of cooking oil (i.e. corn oil, olive oil, palm oil, sunflower oil and walnut oil) were measured at the temperature of 60ºC, 80ºC and 100 ºC for the frequency range of 3 GHz to 8GHz. When the oil is subjected to thermal degradation during heating, the chemical chain of oil will be altered and resulting in physical and internal properties change. It is the key element that led to the variation of Γ. Γ is function of physical-chemical properties of cooking oil that implying the oil quality. In reflection measurement, there are different noticeable results which indicates the used and fresh cooking oil and the effect of heating period
  • Publication
    Derivation and validation of heat transfer model for Spark-Ignition engine cylinder head
    ( 2023-05-05)
    Hassan M.A.S.M.
    ;
    Zuradzman Mohamad Razlan
    ;
    Shahriman Abu Bakar
    ;
    Anas Abdul Rahman
    ;
    Mohd Afendi Rojan
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Ibrahim Z.
    ;
    Ishak A.A.
    ;
    Mohd Ridzuan Mohd Jamir
    The valve train is located in the engine cylinder head, which has various operational heat transfer mechanisms to accommodate the combustion process. Most heat transfer studies in this area have only addressed medium-to high-power vehicles at a single running speed. In this study, a model of an air-cooled underbone motorcycle valve, valve seat, and engine cylinder head was tested to determine the thermal characteristics using actual engine operating conditions at low, medium, and high engine speeds. One-dimensional thermal simulation analyses were conducted to obtain the instantaneous heat-transfer coefficients of an actual engine. The average thermal value was determined as the boundary condition in the three-dimensional thermal analysis. A three-dimensional model was prepared using the ANSYS commercial computational fluid dynamics software package. The results show that as the engine speed increases, so does the thermal load toward the component in the engine cylinder head. The strongest temperature regions were concentrated around the combustion face. The exhaust valve held most of the heat, with the valve neck recording the highest temperature. For the intake valve, the combustion face registered the majority of the heat. The heat flux intensity was gathered in the contact surface area between the valve and its seat, between the valve stem and guide, and between the stem guide and tip section. A thermal survey was used to validate the three modelling results for two separate engine datasets. The cumulative relative errors for intake and exhaust valve seats for low engine speeds were 3.73% and 0.17%, respectively. The intake and exhaust valve seats had cumulative relative errors of 4.12% and 0.70%, respectively, at intermediate speeds. This methodology provides valuable information for analysing the heat characterisation of air-cooled engines. It can also be a useful blueprint for the automotive industry and other researchers involved in thermal measurements.
  • Publication
    Design Optimization of Exhaust Manifold's Divergence Characteristics in Enhancing High-End Power in 115cc SI Engine
    ( 2022-01-01)
    Murali R.
    ;
    Shahriman Abu Bakar
    ;
    Zuradzman Mohamad Razlan
    ;
    Ishak A.A.
    ;
    Ika Syahira Abdullah
    ;
    Mohd Afendi Rojan
    ;
    Ibrahim Z.
    ;
    Wan Khairunizam Wan Ahmad
    The exhaust system especially the exhaust manifold is an essential component that affects the performance of the Spark Ignition (SI) engine. The critical factor inside the exhaust system that affects the engine's performance is backpressure. Backpressure is known as the difference between maximum pressure in the exhaust system and atmospheric pressure. Based on previous studies, it was found that an un-optimal exhaust manifold's design leads to higher backpressure that reduces the performance and the fuel efficiency of the SI engine. This research aimed at enhancing the high-end power of the 115cc SI engine by optimizing the exhaust manifold's divergence characteristics through 1D engine analysis. S/N ratio analysis was used through Taguchi's method as a tool to conduct the design optimization. From the analysis, it was found that the optimal exhaust manifold's divergence configuration improved the mean brake power by 4.67% at high-end engine speed. It is expected that the optimal exhaust manifold's divergence configuration could also improve the engine's brake torque and fuel efficiency which could directly reduce the carbon footprint to the environment.
  • Publication
    A study on the significance of exhaust manifold’s bending angle to the brake torque of 115cc SI engine
    ( 2023-01-01)
    Murali R.
    ;
    Shahriman Abu Bakar
    ;
    Mohd Afendi Rojan
    ;
    Zuradzman Mohamad Razlan
    ;
    Azizul A.I.
    ;
    Rani M.F.H.
    ;
    Mohd Ridzuan Mohd Jamir
    ;
    Sunan S.
    ;
    Ali M.H.A.
    ;
    Ramasamy G.
    ;
    Hisham M.H.N.
    The exhaust manifold is a crucial component of the exhaust system in any SI engine, responsible for efficiently expelling combustion products. However, when the exhaust manifold's design is suboptimal, it leads to negative consequences for the engine's performance due to the presence of backpressure. Backpressure refers to the difference between maximum exhaust pressure and atmospheric pressure. An increase in backpressure decreases the overall performance and fuel efficiency of an SI engine. This study aimed to investigate the bending angle characteristics of the exhaust manifold and the brake torque of the 115cc SI engine using 1D engine analysis. The relationship between the exhaust manifold's bending angle characteristics and the brake torque was analysed using Analysis of Variance (ANOVA) with a p-value of less than 0.05, while the validation with experimental data showed a maximum error of 6.62. In the previous research, it was noted that a lower bending angle leads to better performance. However, the current results indicate that out of the three bending angles considered, having one of them yields the most substantial enhancement in brake torque. The optimized bending angle configuration obtained from the analysis increased the mean brake torque by 0.011 Nm (0.14%). Consequently, this study enhances the average brake torque through the optimal bending angle characteristics of the exhaust manifold. The study's objective aligns with Sustainable Development Goal (SDG) 9: Industry, Innovation, and Infrastructure, as the improved performance achieved through an optimal exhaust manifold design configuration is expected to promote domestic technology development.
      4
  • Publication
    A review on the correlation between exhaust backpressure and the performance of IC engine
    ( 2021-10-25)
    Murali R.
    ;
    Shahriman Abu Bakar
    ;
    Zuradzman Mohamad Razlan
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Azizul A.I.
    ;
    Mohd Afendi Rojan
    ;
    Ma’arof M.I.N.
    ;
    Radzuan M.A.
    ;
    Hassan M.A.S.M.
    ;
    Ibrahim Z.
    The exhaust system in any Internal Combustion (IC) engine is a critical component that affects the engine's performance. A poorly designed exhaust system generally results in an increment of exhaust backpressure. Backpressure is one of the fluid's characteristics that acts as a resistance to exhaust gas flow. Relatively higher backpressure blocks the exhaust gas flow from discharging efficiently, decreasing the engine's performance. In general, higher backpressure results in power and torque loss as well as higher fuel consumption and emission to the environment. This review paper aims to elucidate the relationship between exhaust backpressure and the performance of IC engine. Various past studies were conducted to study the effect of exhaust backpressure on the performance of IC engine through Computational Fluid Dynamic (CFD) simulation, engine simulation and experimental analysis. Some studies used Taguchi's method to optimize the exhaust manifold's design in respect to backpressure decrement. It was found that 0.22 kW to 0.45 kW of engine's power increases for every 1 kPa of exhaust backpressure decrement. At the same time, 1.5% to 3% of fuel consumption decreases for every 10 kPa of backpressure decrement. In contrast, higher backpressure does reduce the Nitrous Oxides (NOx) emission in the exhaust gas due to higher temperature. Therefore, exhaust backpressure must be minimized to improve any IC engine's performance if the NOx emission is neglected. This review paper is expected to provide a better understanding of the impact of exhaust backpressure on IC engine's performance.
      2
  • Publication
    Determination of blind spot zone for motorcycles
    ( 2019-12-02)
    Mohd Sani Mohamad Hashim
    ;
    Hamati A.A.A.
    ;
    Mohd Hafzi M.I.
    ;
    Shahriman Abu Bakar
    ;
    Abdul Halim Ismail
    ;
    Muhamad Safwan Muhamad Azmi
    ;
    Azizi Harun
    ;
    Zuradzman Mohamad Razlan
    ;
    Nur Saifullah Kamarrudin
    ;
    Ishak Ibrahim
    ;
    Mohd Khairul Faizi Abd Rahman
    ;
    Mohd Asrul Md Saad
    ;
    Mohd Afendi Rojan
    The problem of the blind spot zone (BSZ) for motorcycles is common, as it causes many accidents that occur between motorcycles and cars, or motorcycles with other vehicles. The problem of BSZ is occurring for many reasons, such as if the motorcyclist wants to change the lane or manoeuvre or turn without realizing the presence of other vehicle which may cause a terrible collision and leads to casualties, either because of darkness, the full dependence on side mirrors that give a limited scope of vision, or due to a malfunction in the front lights of the car that prevented the motorcyclists from recognizing it. However there were limited research on identifation of BSZ for motorcycle, even though most vehicle accidents in Malaysia involved motorcycles. This paper discusses the initial works on the identification of BSZ for motorcyles. Three types of motorcycles were used to determine the BSZ using grid-based technique. From the data collected, the BSZ was identified for the motorcycles.
      2
  • Publication
    Engine Performance Analysis by Studying Heat Transfer in the Valve Seat through Steady-State Thermal Simulation
    ( 2021-12-14)
    Mohamad Aniq Syazwan Mohamed Hassan
    ;
    Shahriman Abu Bakar
    ;
    Zuradzman Mohamad Razlan
    ;
    Nur Saifullah Kamarrudin
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Mohd Sani Mohamad Hashim
    ;
    Azizi Harun
    ;
    Ishak Ibrahim
    ;
    Azizul Aziz I.
    ;
    Zunaidi Ibrahim
    ;
    Mohd Khairul Faizi Abd Rahman
    ;
    Muhammad Faiz Hilmi Rani
    ;
    Anas Abdul Rahman
    ;
    Mohd Afendi Rojan
    ;
    Rishan Murali
    As the engine reached high speed, the exhaust valve temperature increased exponentially due to the exhaust gas produced by the combustion process between the mixture of air and fuel within the combustion chamber of the internal combustion engine. The valve is subjected to thermal loading due to high temperature and pressure within the cylinder, which must withstand a material temperature for sustainable and optimal operation. To avoid this loss, a perfect medium must be prepared to ensure that the heat is extracted smoothly. This can be done when the valve is in contact with the seat and there is a periodic heat transfer contact. Therefore, it is imperative to research the correlation between valve and valve seat to understand the two sections' heat transfer mechanism. In this study, thermal contact analysis was used to identify heat transfer between the valve and the valve seat as both parts are interconnected. This research also has an interest in studying the two surface conduction mechanisms as the exhaust valve closed in steady-state conditions. Thus, this study portrays a significant method, particularly for the determining the distribution of temperature, heat flux, and heat flux direction between the valve and its seat using ANSYS Workbench.
      2