Now showing 1 - 10 of 60
  • Publication
    The influence of selenium amount added into the graphite box during the selenization of solution deposited CIGSe thin films.
    ( 2021)
    G M Albalawneh
    ;
    M M Ramli
    ;
    M ZM Zain
    ;
    AbstractCu(In,Ga)Se2 (CIGSe) semiconductor is an efficient light absorber material for thin-film solar cell technology. The sequential evaporation of precursor solution, followed by the selenization process, is a promising non-vacuum and low-cost approach for CIGSe thin-film fabrication. The main properties of CIGSe thin films are strongly affected by the post-selenization step. Hence, thorough control of selenization parameters is essential for achieving pure crystalline, large grain films needed for high-performance solar cell devices. In this study, the impact of selenium (Se) amount added during the selenization step was evaluated. The structural, morphological, and compositional properties of the selenized thin films were investigated. The CIGSe precursor film was deposited by a spin-coating technique using a thiol/amine-based solution, followed by annealing with different Se amounts (100, 200, and 300 mg) within a partially closed small round graphite container. In all cases, uniform films of 1.2–1.5 µm thickness with a well-defined single chalcopyrite phase were obtained. It was observed that the grain size and Se content increased with increasing Se mass added. Moreover, the sample selenized with 200 mg Se resulted in higher surface coverage, thinner fine-grained layer, and less MoSe2 formation than the excess Se samples.
  • Publication
    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
    ;
    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.
  • Publication
    Thermosonic vs thermocompression flip chip bonding for low cost system in package
    ( 2018)
    M. R. Lim
    ;
    ;
    Hanizah Aris
    ;
    V. Retnasamy
    ;
    Edward W.C.L.
    ;
    K. Muniandy
    ;
    N. Khan
    ;
    C. S. Foong
  • Publication
    The design and analysis of high Q factor film bulk acoustic wave resonator for filter in super high frequency
    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.
  • Publication
    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
    ;
    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.
  • Publication
    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
    ;
    ;
    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.
  • Publication
    Simulation of The Impact of Bulk Selenium Composition Variation in CIGSSe Solar Cell
    ( 2022)
    G.M. Albalawneh
    ;
    M.M. Ramli
    ;
    M.Z.M. Zain
    ;
    ;
    M. Nabiałek
    ;
    K. Jeż
  • Publication
    Development of copper busbar by silver plating under non-linear load operation using finite element method (FEM)
    (AIP Publishing, 2023-04)
    Muhammad Hafiz Ab Aziz
    ;
    Muhammad Mokhzaini Azizan
    ;
    ;
    Generally, busbars are used in electrical transmission and distribution power. The presence of harmonic current in the busbar will generate more heat to the system. The generation of heat will be increasing power losses at the busbar and reduced their conductivity. A three-dimensional (3D) Finite Element Method (FEM) by COMSOL Multiphysics software was used in this research to analyze the heat distribution, average temperature, and power losses of copper busbar with 0.5 mm silver plating on their surface. The dimension of 30 mm × 4 mm × 500 mm copper busbar was utilized based on their suitable current carrying capacity from the measured location. The current source starts from 419 A and varies from 0% until 50% of Total Harmonic Distortion (THD) with an interval of 5%. The findings show improvement condition of copper busbar after silver plated on their surface. The bare copper busbar only meets the requirement range condition of BS159:1992 until the existence of 15% Total Harmonic Distortion of current (THDi) component while silver-plated copper complies until the maximum value of THDi which is 50%.
  • Publication
    Breast surface variation phase map analysis with digital fringe projection
    (SPIE, 2019)
    Wan Mokhzani Wan Norhaimi
    ;
    ; ;
    Mukhzeer Mohamad Shahimin
    ;
    MAM Azmi
    ;
    Wong, K.
    ;
    Vithyacharan Retnasamy
    ;
    Rajendaran Vairavan
    ;
    Christopher R. Valenta
    ;
    Masafumi Kimata
    Breast carcinoma has become one of the most frequently diagnosed life threatening cancer among women. Early detection of breast cancer is highly essential with the aid of non-contact imaging modalities. Recently, non-contact breast imaging methods based on fringe projection has been developed for breast surface change inspection. In this work, a non-contact digital fringe projection imaging modality that utilizes phase shifting fringe patterns for identifying surface changes has been developed for investigating breast surface changes caused by the presence of tumors. A medical grade prosthetic breast was used as the experimental subject and subjugated to breast changes through the enlargement of a round shaped silicon catheter as a tumor. The fringes were projected onto the breast surface based on the three steps phase shift fringe projection. The fringe patterns consisted of a large fringe width to enable the breast image to be confined in fewer fringe patterns. A resulting phase map was obtained where pixel coordinate marking was conducted on the phase map breast image. Each of the pixel’s coordinate was compared to identify the location of the surface changes. A range of 2-9 pixel coordinate shifts from the 0.5 – 2 cm tumor growth were obtained from the results which demonstrated the capability of using phase map analysis from digital fringe projection in identifying surface changes of the women’s breast.
  • Publication
    Integration of microfluidic channel on electrochemical-based nanobiosensors for monoplex and multiplex analyses: An overview
    ( 2023-05-01)
    Adam H.
    ;
    ; ;
    Adam T.
    ;
    ; ;
    Fakhri M.A.
    ;
    Subramaniam S.
    ;
    Chen Y.
    ;
    Sasidharan S.
    ;
    Wu Y.S.
    Background: Microfluidic devices have evolved into low-cost, simple, and powerful analytical tool platforms. Herein, an electrochemically-based microfluidic nanobiosensor array for monoplex and multiplex detection of physiologically relevant analytes is reviewed. Unlike other analyte detection methods, microfluidics-based embedded electrochemical nanobiosensors are portable, custom electrochemical readers for signal reading. Methods: Microfluidic devices and electrochemical sensors can be integrated into monoplex or multiplex systems. The integrated system is simple to use and sensitive, and so has great potential as a powerful tool for profiling immune-mediated treatment responses in real time. It may also be developed further as a point-of-care diagnostic device for conducting near-patient tests using biological samples. Therefore, using mutiplex analysis, a biosensor array may detect multiple analytes in a sample solution and provide different outputs for each analyte. A microfluidic electrochemical nanobiosensor, for example, can detect urine glucose, lactate, and uric acid. The microfluidic array of integrated nanobiosensors and electrochemical sensors enables fast and cost-effective selection of high-quality and statistically significant diagnostic data at the point of care. The multiplex analytical test is an important molecular tool for academic research as well as clinical diagnosis. Although key approaches for analysing numerous analytes have been developed, none of them are suitable for point-of-care diagnostics, especially in situations with limited resources. Significant findings: In this study, monoplex and multiplex microfluidic assays for rapid measurement of single and multiple analytes at the point of care are presented. Since this test can analyse both single and multiple analytes, it is exceptionally specific, easy to use, and inexpensive. The ability of integrated electrochemical-based microfluidic devices with single channel and multiple channels systems to perform monoplex and multiplex analysis simultaneously and independently is the novelty of this review.
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