Now showing 1 - 10 of 40
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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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Extraction, preparation and application of anthocyanin pigments from mulberry using polar solvent in various pH as photosensitizer for dye-sensitized solar cells

2021-12 , Suriati Suhaimi , Nur Syakimah Ismail , Zaliman Sauli

The purpose of this study is to evaluate the effect of polar solvent acetone and ethanol towards Morus nigra L. (Mulberry) anthocyanin dye extraction and suitable solvent sensitization of the same extracted dye on mesoporous titanium dioxide (TiO2) for dye-sensitized solar cells (DSSCs) applications. Polar extraction solvent, namely acetone, ethanol and combination of polar protic and polar aprotic solvent of acetone and ethanol which containing of 0.5% and 1% hydrochloric acid (HCl) were employed to extract anthocyanin natural dye from Mulberry. The dye extraction effectiveness and dye active component was analysed using-ultraviolet-visible spectroscopy and fourier transform infrared. Then, the extracted dye sensitization over TiO2 was monitored with current-voltage characteristic to obtain the cell power conversion efficiency. The DSSCs equipped with Mulberry extraction achieved the conversion efficiency in ranged of 0.0003% to 0.30%. Open circuit voltage and current densities obtained ranged from 0.024 to 0.574 V and 0.0023 to 0.352 mAcm-2. The performance of the fabricated cells was investigated at various pH values in presence of acidic environment in Mulberry dye extractions. This work provide an insight into the importance of choosing a right medium for photosensitizer as well as the favourable solvent for mulberry anthocyanin dye adsorption on TiO2 photoanode.

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Critical analysis of stability and performance of organometal halide perovskite solar cells via various fabrication method (Review)

2017 , Suriati Suhaimi , Zaliman Sauli , Nor Azura Malini Ahmad Hambali , Mohamad Halim Abd. Wahid , Vithyacharan Retnasamy , Mukhzeer Mohamad Shahimin

Organometal halide perovskite solar cells (Omh-PSCs) have attracted attention due to its unique electrical and optical properties. Ideally, the Omh-PSCs should remain free from degradation under normal operating conditions for several years, preferably tens of years. In order to produce high power conversion efficiency with low potential of degradation, different fabrication methods have been developed. The reported stability of perovskite films can vary significantly and reported to decay substantially up to 20% of its original performance. A thorough understanding of fabrication process upon the stability of the device is regarded as crucial to pave the way for future endeavors. This review summarized and highlighted the recent research of fabrication methods that gave an impact to the stability of perovskite devices.

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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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A 12 GHz LC-VCO Implemented with S’ shape Inductor using silicon-on sapphire substrate

2022-12 , Nazuhusna Khalid , Aimi Noorliyana Hashim , Nurul Izza Mohd Nor , Shahrir Rizal Kasjoo , Zaliman Sauli , Mohd Norhafiz Hashim , M.S Mispan

A voltage-controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by a voltage input. In a VCO, low-phase noise while consuming less power is preferred. The tuning gain and noise in the control signal produce phase noise; more noise or tuning gain implies more phase noise. Sources of flicker noise (1/f noise) in the circuit, the output power level, and the loaded Q factor of the resonator are all crucial factors that influence phase noise. As a result, creating a resonator with a high Q-factor is essential for improving VCO performance. As a result, this paper describes a 12 GHz LC Voltage- Controlled Oscillator (VCO) employed with a ‘S’ shape inductor to improve phase noise and power performance. The phase noise for the VCO was reduced using a noise filtering technique. To reduce substrate loss and improve the Q factor, the inductor was designed on a high-resistivity Silicon-on Sapphire (SOS) substrate. At 12 GHz, the optimised S’ shape inductor has the highest Q-factor of 50.217. At 10 MHz and 100 MHz, the phase noise of the 12 GHz LC-VCO was -131.33 dBc/Hz and -156.71 dBc/Hz, respectively. With a 3.3 V power supply, the VCO core consumes 26.96 mW of power. Based on the findings, it is concluded that using an ‘S’ shape inductor in the VCO circuit will enable the development of low-cost, high-performance, very low-power system-on-chip wireless transceivers with longer battery life.

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Analysis on square and circular inductor for a high Q-factor inductor

2021-12 , Aimi Noorliyana Hashim , Nazuhusna Khalid , Nurul Izza Mohd Nor , Shahrir Rizal Kasjoo , Zaliman Sauli

This paper presents the high-quality (Q) factor inductors using Silicon-on-sapphire (SOS) for the 10GHz to 20GHz frequency band. Inductors are designed on SOS because of their advantages, including high resistivity and low parasitic capacitance. This paper compares square and circular inductor topologies for high-quality (Q) factor inductors using HFSS software for the high-frequency band. Both inductors have been designed with the same width and thickness to make them comparable with each other. The comparison shows that a circular inductor achieves the highest Q-factor. Furthermore, the circular and square inductor's Q-factor, inductance, and resistance are analyzed. As a result, the circular inductor has the maximum Q-factor of 89.34 at 10.6GHz for 0.29nH, while the square inductor has obtained a maximum Q-factor of 80.72 at 10GHz for 0.40nH inductance.

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Kinetics, mass transport characteristics, and structural changes during air-drying of purple yam (Dioscorea Alata L.) at different process conditions

2017 , Flordeliza C. De Vera , Leif Anthony B. Comaling , Iya Ray Alyanna M. Lao , Alvin R. Caparanga , Zaliman Sauli

This experiment was designed to follow the 2k factorial design to study the effects of the three drying parameters on the drying characteristics and effective moisture diffusivity and to fit each run performed on the best thin-layer drying kinetics model. Raw purple yam samples were pre-treated and undergone the designed drying procedures at which the weight of the samples were recorded every minute until such time that the sample weights become constant. Scanning Electron Microscopy (SEM) is utilized for qualitative analysis of the dried samples. The number of pores per unit area and the overall aesthetics of the surface of the dried samples were compared also using SEM. Considering the qualitative analysis conducted on the samples from the images of SEM, dried samples from run 2 has the most desirable conditions such as high temperature and low air velocity for drying because the samples from this run have large pore diameters with minimal cell breakages.

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Interrogation of surface roughness and bond force effect

2013 , Zaliman Sauli

In the macro world surface roughness is a feature undoubtedly not to be ignored. In the current trend towards the nano-scale feature in the devices related to the semiconductor and other various niche, surface roughness is being propelled as an important element. In this work the surface roughness at nano level is investigated for the adhesion interaction and influence. The samples for the roughness feature and ranges were prepared using controlled plasma etching. The wire bonding bond force parameter was chosen as the factor to be tested and shear test as the response. The shear value ranged from 13g to 22g for the low to high bond force respectively for the lower range surface roughness, for the higher surface roughness the value ranged 5g to 9g respectively. The interaction shows surface roughness has tangible effect on adhesion for a more thorough detailed investigation.

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The design and analysis of high Q factor film bulk acoustic wave resonator for filter in super high frequency

2021-12 , Nurul Izza Mohd Nor , Nazuhusna Khalid , Nur Anira Asyikin Hashim , Shahrir Rizal Kasjoo , Zaliman Sauli , Lam Hok Lang , Chow Shi Qi

Filtering process is one of the highlighted issues when the operating frequency is up to medium or high GHz range in wireless transceiver system. The development of high performance, small size, filter on chip operating in GHz frequency range is the requirement of present and future wireless transceiver systems. The conventional frequency bands, below 6 GHz are already congested, thus, to satisfy this demand, the research into transceiver systems working at frequencies higher than 6 GHz has been growing. Therefore, this work proposed the design and optimization of film bulk acoustic wave resonator (FBAR) operating in frequency 7 GHz to 10 GHz with high quality (Q) factor. The effect of using different geometrical parameters to achieve high Q factor FBAR in these frequency bands is analysed. The designed FBAR achieved Q factor of 1767 at 7 GHz and 1237 at 10 GHz by using aluminium nitride as the piezoelectric thin film and molybdenum as the electrode.

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Effects of pH and concentration on the capability of E. coli and S. epidermidis with bentonite clay as biosorbent for the removal of Copper, Nickel and Lead from polluted water

2017 , Delia B. Senoro , Josel B. Godezano , Meng-Wei Wan , Lemmuel L. Tayo , Zaliman Sauli , Hasnizah Aris

This paper discusses the effects of pH and concentration on the capability of E. coli ATCC29522 and S. epidermidis RP62A biofilm with bentonite in removing divalent copper, nickel and lead from wastewater. Batch adsorption study at laboratory scale was utilized to evaluate the potential use of bacterial biomass (E. coli ATCC29522 and S. epidermidis RP62A) aided with geosynthetic clay (bentonite) for the removal of Cu2+, Ni2+and Pb2+. Results revealed that removal of Cu2+, Ni2+and Pb2+ by both types of organisms supported with bentonite were high in the first 4 hours of the experiment. This illustrates that the binding site on that particular time was abundant. Hence, the removal rate was evident at high concentration depicting the line adsorption equilibrium. It also revealed that S. epidermidis RP62A supported with bentonite had the highest affinity to Copper and Lead with Qm = 277.7 mg/g and 5.0075 mg/g, respectively. While E. coli ATCC 29522 had the highest affinity to Nickel (Qm= 58.82 mg/g). Hence, the sorption of Cu2+, Ni2+and Pb2+ onto E. coli ATCC29522 and S. epidermidis RP62A biofilm supported with bentonite clay occurred through monolayer chemisorption on the homogeneous surface of E. coli ATCC29522 and S. epidermidis RP62A biofilm with bentonite clay. Batch kinetics studies revealed that the sorption of Cu2+, Ni2+and Pb2+ onto E. coli ATCC29522 and S. epidermidis RP62A biofilm supported with bentonite clay was well described by a pseudo-second-order equation model of type 1 (R2 = 0.9999), which implies that chemisorption is the rate limiting step.