Wan Mokhdzani Wan Nor Haimi
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Wan Mokhdzani Wan Nor Haimi
Official Name
Wan Mokhdzani, Wan Nor Haimi
Alternative Name
Norhaimi, W. M. W.
Norhaimi, Wan Mokhzani Wan
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Scopus Author ID
55533946600
Researcher ID
DKW-9931-2022

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Simulation and investigation of Si-based piezoelectric micromachined ultrasonic transducer (PMUT) performances

2023-07 , Hasnizah Aris , Muhammad Nizam Bin Rosli , Mohammad Nuzaihan Md Nor , Zaliman Sauli , Wan Mokhdzani Wan Nor Haimi

Micro-electromechanical system (MEMS) based piezoelectric ultrasonic transducers for acoustic imaging of the surroundings are known as piezoelectric micromachined ultrasonic transducers (PMUTs). This research proposes a structural design of the PMUT with four fixed-guided beams. The beam is subjected to lateral loads, with vectors that are perpendicular to the longitudinal axis. This project simulated Piezoelectric Micromachined Ultrasonic Transducer (PMUT) with three different material properties i.e. Aluminium Nitride (AlN), Lead zirconate titanate (PZT) and Zinc Oxide (ZnO). Based on the study, it was found that reducing the beam dimensions and increasing the plate size will result in the first mode frequency reduction from 1.33x107 Hz to 3.74x106 Hz. Other than that, it was found that AlN PMUT experienced the maximum deflection of 6.3413 to 6.3478 μm when the loads applied in the range of 50 to 200 μN/m2. When the piezoelectric material changed to PZT, we obtained the maximum deflections of 0.3771 to 0.3786 μm when the same loads range applied to the PMUT. As for the ZnO PMUT, the maximum deflections obtained were in between 0.1702 μm to 0.1772 μm with the loads are maintained as in the loads applied to the AlN and PZT. This study proved the significant impact of altering the structural dimensions and material properties of PMUTs on their operational characteristics, specifically the first mode frequency and deflection behavior.

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Simulation and investigation of high-frequency Si-based piezoelectric micromachined ultrasonic transducer (PMUT) performances

2024-02-08 , Aris H. , Kaharuddin N.A.A. , Zaliman Sauli , Aziz A.A. , Wan Mokhdzani Wan Nor Haimi

The application of ultrasonic transducers is relying on the frequency which the transducers resonated. In the imaging application, an ultrasonic transducer should possess resonant frequency that higher than 2 MHz while in ultrasound testing, a range of 2 to 10 MHz is seeming to be adequate. This report is investigating the performance of high frequency Si-based PMUT with different piezoelectric material used in the structure. The piezoelectric materials used are Aluminium Nitride (AlN), Lead Zirconate Titanate (PZT), and Zinc Oxide (ZnO). Using the same dimensions, the obtained resonant frequencies of PMUT are 4.0370 MHz, 2.8224 MHz, and 3.4358 MHz for AlN, PZT and ZnO respectively.

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Digital fringe projection for hand surface coordinate variation analysis caused by osteoarthritis

2017 , Wan Mokhdzani Wan Nor Haimi , Cheek Hau Tan , Vithyacharan Retnasamy , Rajendaran Vairavan , Muhammad Hafiz Ab Aziz , Zaliman Sauli , Nor Roshidah Yusof , Nor Azura Malini Ahmad Hambali , Ahmad Syahir Ahmad Bakhit

Hand osteoarthritis is one of the most common forms of arthritis which impact millions of people worldwide. The disabling problem occurs when the protective cartilage on the boundaries of bones wear off over time. Currently, in order to identify hand osteoarthritis, special instruments namely X-ray scanning and MRI are used for the detection but it also has its limitations such as radiation exposure and can be quite costly. In this work, an optical metrology system based on digital fringe projection which comprises of an LCD projector, CCD camera and a personal computer has been developed to anticipate abnormal growth or deformation on the joints of the hand which are common symptoms of osteoarthritis. The main concept of this optical metrology system is to apply structured light as imaging source for surface change detection. The imaging source utilizes fringe patterns generated by C++ programming and is shifted by 3 phase shifts based on the 3 steps 2 shifts method. Phase wrapping technique and analysis were applied in order to detect the deformation of live subjects. The result has demonstrated a successful method of hand deformation detection based on the pixel tracking differences of a normal and deformed state.

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Digital fringe projection system for round shaped breast tumor detection

2020-01-01 , Wan Mokhdzani Wan Nor Haimi , Zaliman Sauli , Hasnizah Aris , Vithyacharan Retnasamy , Rajendaran Vairavan , Muhamad Hafiz Ab Aziz

The digital fringe projection has been widely used in the field of surface imaging however its application in the field of body imaging especially for human breasts is still quite limited. Currently, the common imaging modality for breast tumor diagnoses are breast ultrasound and mammogram. There are advantages and limitations of using the mammogram and ultrasound in terms of the procedure of the process and the non-invasive nature of the procedure. In this work, an automated digital fringe projection system is developed to execute the imaging of surface changes of a helical shaped phantom breast. The fringe projection setup utilizes a computer, LCD projector, and a CCD camera. The tumor used was round-shaped with a diameter size of 1.5 and 2 cm. The fringe pattern was projected through the three-step phase shift where a resulting phase map was obtained. Results demonstrated that the system was able to identify an average pixel shift of five and ten on the breast surface caused by the presence of the round breast tumors.

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Design and simulation of micro-electro-mechanical systems (MEMS) capacitive pressure sensor for thermal runaway detection in the electric vehicle

2023-12 , H. M. M Hajizi , Hasnizah Aris , Wan Mokhdzani Wan Nor Haimi , Nurul Izza Mohd Nor , Zaliman Sauli , A. A. Aziz

Recent advancement of vehicle technologies has resulted in development of replacing conventional Internal combustion engine (ICE) to Electric Vehicle (EV) mostly powered by Lithium-ion batteries (LIB). These batteries contain massive amount of energy confined in a very small space. Thermal runaway occurs when the batteries and its circuits start to heat up anomaly. Thermal runaway can cause failures that can lead to battery ignition, resulting in explosions and imminent threats to life and property. This research focused on MEMS capacitance pressure sensor, using three distinct square slotted diaphragm designs: clamped-square, four-slotted-square, and eight-slotted-square diaphragms. The investigation commenced with an evaluation of diaphragm performance, and subsequently, the diaphragm was integrated into the structure of the MEMS capacitive pressure sensor and subjected to simulation. Varied pressure levels ranging from 0.1 to 0.35 MPa were applied to both the diaphragm and the pressure sensor. The outcomes revealed that the eight-slotted-square diaphragm yielded the most substantial displacement, registering at 5.507 μm. It also exhibited the highest Mises stress of 644.67 MPa, and recorded the highest mechanical sensitivity at 15.7545 (10-12/Pa). The clamped-square design, despite its slotted area, yielded the highest capacitance value among the three designs for the pressure sensor.

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Microchannel interrogation with Twyman-green interferometer

2011 , Wan Mokhdzani Wan Nor Haimi

The Twyman-Green Interferometer (TGI) setup for measuring microfluidic channel depth has been developed. The main objective of this study is to develop a non-contact measuring instrument capable of performing depth measurements of a microfluidic channel made of silica wafer. The microfluidic channel is fabricated using the photolithography process and reactive ion etching. Microfluidic channel depth has been measured with the Twyman-Green Interferometer setup. The interferometer setup relies on the optical path length change caused by the rotating transparent silica reference sample in one of its arms. Intensity of fringes produced by the interferometer is detected and recorded with a corresponding photodiode. The intensity results are plotted against the optical path variation of the reference sample which causes an optical path difference in the reference arm. Depth measurement of the microfluidic channel has been extracted from the optical path difference obtained from the interferometer setup. Transparent silica reference samples with etched thickness of 0.681 μm (Ref 1), 1.396 μm (Ref 2) and 2.102 μm (Ref 3) has been used to investigate and determine which is the most accurate reference sample to be used in determining depth of microfluidic channel. Depth of microfluidic channel obtained from Twyman-Green Interferometer has been compared to depth results obtained from atomic force microscopy and surface profilometer. Applying Ref 1, Ref 2 and Ref 3 as rotating reference samples yielded 94.45 %, 84.76 % and 66.97 % compliance with measured depth obtained from surface profilometer. Although there are slight variations with results obtained from surface profilometer and atomic force microscopy, the experimental results proves that the Twyman-Green Interferometer is able to determine microfluidic channel depth and etched depth of thin Si samples. Resolution of the TGI setup is 0.27 μm and is suitable to measure depth profiles ranging from 0.27 μm to 5 μm. Therefore, the modified TGI setup in this research is suitable for measurements of depths or thickness profiles ranging from 0.27 μm to 5 μm with a fringe visibility of more than 0.5.

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