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- PublicationEffect of heat sink configuration on Thermal management of different Semiconductor modules using Regression models.(2025-03)As semiconductor devices miniaturize and increase in power density, effective thermal management becomes critical to ensure optimal performance, reliability, and longevity. Traditional cooling methods often fail to meet the thermal demands of highpower electronics, requiring extensive testing and lengthy lead times. This study introduces a novel approach to address these challenges by developing reliable thermal models and a predictive framework to optimize heat sink designs for semiconductor devices, particularly for high-performance applications such as external SSDs.Key innovations include a stacked 3D model utilizing the Finite Volume Method (FVM) to predict thermal gradients and hotspots without relying on complex architectural data, making the model versatile for a wide range of semiconductor devices. Unlike traditional methods, which rely solely on equations and experimental data to determine junction temperature, this study enables direct access to junction temperature based on changes in heat sink design. The study also uniquely integrates heat sink configurations directly into the semiconductor module, allowing real-world testing of their impact on junction temperature reduction.By analyzing ten power dissipation levels (ranging from 10% to 100% of a maximum 2.6W), results show that increasing power dissipation significantly reduces junction temperature (by 7°C to 68°C), emphasizing the importance of optimizing surface heat transfer coefficients. The study also evaluates heat sink configurations such as fin number, fin height, and base dimensions to identify optimal designs. Increasing fin height from 0 mm to 25 mm reduced junction temperature by 18.17%, while optimizing the number of fins (from 0 to 8) achieved a reduction of 8.68% at a power level of 0.55W, with 4 fins providing the best balance between heat dissipation and minimal volume. Larger base areas and thicker bases further enhanced thermal performance, reducing junction temperatures from 81.18°C to 62.72°C and from 73.26°C to 63.47°C, respectively. However, the study highlights that overly packed fins or larger bases can impede airflow and heat transfer efficiency, underscoring the need for careful optimization.To provide predictive insights, linear and polynomial regression models were employed to estimate the impact of heat sink designs on junction temperatures. The linear regression model consistently outperformed the polynomial model, offering a reliable framework for optimizing thermal solutions, particularly for lower-power chips. This research provides actionable guidelines for designing efficient thermal management systems, reducing lead times, and enhancing the reliability of semiconductor devices through advanced thermal modeling and predictive techniques.
- PublicationComputational fluid dynamics Analysis of capillary underfill flow In heterogeneous packaging.(2025-08)This study uses computational fluid dynamics (CFD) to optimize capillary underfill flow (CUF) in heterogeneous chip packages by examining geometric and dispense setup attributes. The investigation into geometric attributes, specifically the spacing between Chip 1 and Chip 2 (𝑆12) and chip thickness (𝑡𝑐), identified an optimum spacing of 𝑆12 at 5.71, allowing the underfill to reach Chip 3 and fill Chip 1 and Chip 2 almost simultaneously. Additionally, greater chip thickness ratios (𝑡𝑐𝑟) of 22.29 improve flow efficiency by providing a larger cross-sectional area, reducing hydraulic resistance. The study also examined the effect of dispense setup attributes, such as underfill dispense weight (𝐷𝑠𝑊) and length (𝐷𝑠𝐿), on CUF dynamics. Optimal dispense weight ratios (𝐷𝑠𝑊𝑟) of 1.00 and length ratios (𝐷𝑠𝐿𝑟\) of 0.70 significantly improve flow uniformity and reduce void formation, ensuring a reliable encapsulation process. Furthermore, analysis of varied dispense patterns (𝐷𝑠𝑃) and lengths (𝐷𝑠𝐿) in a four chips arrangement showed that the double-I pattern optimizes CUF behavior by minimizing voids and ensuring efficient underfill distribution. A 50% dispense length was identified as optimal, achieving full coverage more rapidly than 100% and 30% lengths, with negligible void percentages. This approach provides valuable insights for optimizing chip package designs, enhancing performance and reliability.
- PublicationAir-liquid interface cultivation of navicula incerta on hollow fiber membranes for nanocellulose hydrogel preparation in dye removal applications.(2025-08)Microalgae is a sustainable source with the potential to lower both energy demand and chemical usage in the process of nanocellulose production. However, the sustainability of microalgae cultivation remains questionable due to the large footprint of open ponds and the low cultivation yield per volume in photobioreactors. In this study, hollow fiber membranes with high packing density and a larger effective membrane surface area per unit volume were proposed to improve the air-liquid interface cultivation of Navicula incerta. The effects of different membrane coatings on the growth rate and the harvesting efficiency were studied. In addition, sodium bicarbonate (NaHCO3) was added to the medium to understand the carbon capture potential of the system before harvesting and processing the microalgae into nanocellulose, which was useful in improving hydrogel adsorbent. N. incerta was successfully grown on the porous membrane surface with the nutrients circulating inside the lumen. Both fourier transform infrared (FTIR) spectra and scanning electron (SEM) images showed the accumulation of extracellular organic matter. Hydrophilic polysaccharides such as sulfated and uronic-acid reduced water contact angles (WCA) on polyethersulfone (PES) and poly(vinylidene fluoride) (PVDF) membranes. PVDF hollow fiber membranes with dead-end configuration improved the cell growth rate by 54.0%. However, the growth rate on PES hollow fiber membranes only fell between 18.7 and 38.0% due to weak cell adhesion. PVDF hollow fiber membranes were further modified with different biocoatings before cultivation. The WCA measurement revealed that bovine serum albumin (BSA) coating significantly increased surface hydrophobicity and boosted antioxidant astaxanthin accumulation in microalgae, enhancing cell proliferation. The zeta potential measurement proved that BSA increased the adhesion energy, leading to the highest growth rate of N. incerta of 67.3%. In addition, NaHCO3 could act as the additional carbon source in the nutrient to cultivate N. incerta on BSA-PVDF hollow fiber membranes. The highest growth rate of 81.7% was obtained at 8 g/L NaHCO3 with a harvesting efficiency of 81.02%. The carbon fixation rate, carbon utilization efficiency, and chlorophyll content were 375.45 ± 15.89 mg/L/d, 58.91 ± 6.96%, and 4.22 ± 0.28 mg/L, respectively. The increasing NaHCO3 concentration raised the availability of inorganic carbon in the nutrient supply, thus increasing the carbon fixation of microalgae during photosynthesis. Nanocellulose from N. incerta was further extracted to synthesize hydrogel adsorbents. The maximum nanocellulose yield of 53.4 ± 2.5% was achieved using sulphuric acid with a concentration of 60%(v/v). The methylene blue adsorption capacity of the hydrogel adsorbents rose from 30.79 mg/g to 106.31 mg/g. A dye removal percentage as high as 89.7% was achieved due to the hydrogen bonding and electrostatic interaction with carboxylate groups, leading to potential applications in coloured wastewater treatment.
- PublicationDevelopment of niosomes containing deep eutectic solvents to enhance curcumin bioavailability.(2025-05)Curcumin, a potent medicinal compound, exhibits poor aqueous solubility and low oral bioavailability, limiting its therapeutic potential. This study aims to enhance curcumin’s bioavailability by encapsulating it in niosomal formulations incorporating natural deep eutectic solvents (NADES). NADES were synthesized using betaine as the hydrogen bond acceptor (HBA) and various hydrogen bond donors (HBD), with betaine-glucose (BG), betaine-fructose (BF), and betaine-xylose (BX) exhibiting the highest curcumin solubility at 6.16±0.61 mg/g, 6.03±0.25 mg/g, and 5.57±0.14 mg/g, respectively. These NADES were integrated into curcumin niosomes, formulated in four different mass variations (25 mg, 50 mg, 75 mg, and 100 mg). Characterization studies confirmed the spherical shape of the niosomes, with entrapment efficiency ranging from 82.20±0.46% (BX1) to 97.61±0.67% (BG4), significantly exceeding blank niosomes (74.27±0.20%). Zeta potential measurements indicated enhanced electrostatic stability in eutectic-based niosomes (-45.50±2.55 mV to -53.70±1.63 mV) compared to blank niosomes (-17.57±0.90 mV). Raman spectroscopy revealed optimal molecular interactions in BG4, with an intensity ratio (I2930/I2850) of 0.3106. Stability studies demonstrated that NADES-niosome formulations retained their physicochemical properties over 28 days under various temperature conditions, with BG4 exhibiting the longest photochemical half-life (158.56 days). Antioxidant assays indicated improved activity in NADES-based niosomes, reflected in lower IC50 values. In vitro drug release studies showed a sustained release profile where Korsmeyer-Peppas model indicated a non-Fickian diffusion mechanism, with swelling and dissolution influencing curcumin release. The Peppas-Sahlin model further confirmed an initial diffusion-dominated release, shifting to relaxation-driven release over time, particularly in eutectic-based niosomes. Furthermore, the effect of cryoprotectants on freeze-dried niosomes was examined, revealing that mannitol at 10 g/g significantly improved physicochemical properties, reducing particle size (870.0 ± 15.52 nm to 418.07 ± 5.95 nm), decreasing polydispersity index (0.34 ± 0.016 to 0.12 ± 0.04), and increasing entrapment efficiency (75.75 ± 6.12% to 93.24 ± 3.21%). The zeta potential also increased from -38.87 ± 0.32 mV to -45.33 ± 3.99 mV. This study presents a novel approach for enhancing curcumin delivery by integrating NADES into niosomal formulations and optimizing freeze-drying with mannitol, offering a promising strategy for improving curcumin’s stability and bioavailability.
- PublicationSmartphone based imaging with spirodella polyrhiza for water quality monitoring with the aid of computational modelling.(2025-06)The demand on clean water had stimulated the development of various water monitoring technique. From the conventional to the advance monitoring, the efforts were directed towards developing rapid, sensitive and easily operated methods. To address the problem whereby the conventional water quality monitoring relied on the chemical usage and tedious procedure, the present study proposed an innovative smartphone-based imaging technique for the detection and prediction of water contamination. The prediction is based mainly by interpreting the physical changes of a bioindicator, after exposed to different type and concentration of contaminants. The research initiated by evaluating effects of macronutrients on the biochemical changes in a species of duckweed, Spirodella. polyrhiza with machine learning approaches, followed by establishing the framework for smartphone-based imaging estimation of mass, chlorophyll and anthocyanins. A smartphone was used to capture the images of S. polyrhiza and captured image was processed with ImageJ software to extract the color signal. The color signal from the images were correlated with the exact determined amount of chlorophyll and anthocyanins. The mean green (G) value of the image was a robust parameter to predict chlorophyll contents in S. polyrhiza with a high r2 of 0.9693 and the lowest error compared to other color parameters and their combinations. Furthermore, the accuracy for the estimation of mass and chlorophyll under magnification was tested. A similar approach was carried out and the magnifications were employed with a microscope. The image captured was analyze and correlation was established. For chlorophyll estimation, the best magnification to be used was 2.5x magnification, and the derived color combinations, square root of R+G+B has the highest r2 value which is 0.7166. Machine learning algorithms were used to further improved the generated model to the r2 value of 0.72. External factors were evaluated by capturing images under the influence of distance, light intensity, correlated color temperature and smartphone model variation. The external factors were found to affect the output from images. Final study involved the development of classification model for estimating type of contaminants and prediction model for anticipate the concentration of contaminants. The classification models were good in classify the type of dye and predicts with general class of contaminants. The predictive model developed works well with the concentration of oil, methylene blue, chromium, cadmium and silver (r2= 0.8561, 0.9464, 0.8326, 0.9727 and 0.9529 respectively). Smartphone-based imaging with S. polyrhiza had been proven workable in predicting the contamination in water.
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- ItemDoes Shareholder Concentration Matter In Small And Medium Enterprises (SMES)? Empirical Evidence From SMES In Manufacturing Sector In Northern Corridor Economic Region (NCER).(Universiti Sains Malaysia, 2009-06)Given the important role of SMEs as a growth factor in local economy, ensuring a strong and competitive development for this industry segment has become a key concern in making the Northern Corridor Economic Region (NCER) a success. This study investigates the effects of shareholder concentration, together with financial inputs and outputs on the relative operating efficiency in utilization of financial resource (financial efficiency) for SMEs in manufacturing sector in NCER for the financial year 2007. The financial efficiency is derived from Data Envelopment Analysis (DEA). DEA shows that only 27 SMEs scored 100% efficiency, and they are mostly from Penang and Perak. This study delivers three important findings: first, shareholder concentration does affect the financial efficiency for SMEs involved in manufacturing sector in NCER; second, lower financial inputs and higher financial outputs produce higher financial efficiency SMEs involved in manufacturing sector in NCER; third, the distribution of financial efficiency is not balance across the three states in NCER. The last point is consistent with the Korean case reported in Yang (2006).
- PublicationPredicting occurrence of rainfall using discriminant analysis(2009-04-01)Malaysia has a tropical climate that is consistently hot with high frequent rainfall. Water is one of the most vital natural resources for all life on Earth. So, it is important to quantify it accurately. Rainfall rate is affected by some unpredicted weather conditions such as humidity, air pressure, temperature and wind speed which are liable to change. The relationship between the rainfall rate (dependent variable) to the humidity, temperature, air pressure, and wind speed (independent variables) is analyzed by the method of discriminant analysis using the SPSS 15.0 software. A total of 340 cases for year 2008 were used to develop a model to discriminate among the 2 levels of rainfall rate which is rain or no rain. The aim of this project is to develop a set of discriminating functions to predict the category of the rainfall rate. The usefulness of a discriminant model is based upon its accuracy rate, or ability to predict the categories of the dependent variable. As a conclusion, the discriminant analysis in this study successfully estimates the categories of the rainfall rate. The accuracy is high that is 84.7%. So, the results show that the discriminant analysis can be considered as an effective tool in forecasting the type of rainfall condition.
- PublicationIpo Information Disclosure And Price Stabilisation Action From The Perspective Of Information Asymmetry In Hong Kong Listed Companies(2024-08)The topics of IPO have attracted attentions from scholars for a long time. Among these research topics, price stabilisation, which is an aftermarket action taken by underwriters, is relatively less concentrated by prior studies. Factors which cause the stabilisation done by underwriters are not clear, owing to the barrier resulted from the non-mandatory disclosure of such actions in many countries. Meanwhile, as a compulsory document for IPO issuers, the prospectus contains sufficient information for investors to make decision for IPO investment. Recent studies have focused on the information disclosed in IPO prospectus, such as the text content and textual tone, and its corresponding influence on market performance. Yet, studies which have investigated the relationship between the information disclosure of IPO prospectus and price stabilisation are scarce. This thesis probes into the potential factors of price stabilisation from the theoretical perspective of information asymmetry by examining how the information disclosed in the IPO prospectus can impact the aftermarket stabilising actions using a sample data from 2004 to 2021 in Hong Kong stock market. Specifically, the effects of the information disclosure related to cornerstone investors, Chinese state ownership, as well as the narrative uncertainty contained in the prospectus, are investigated using ordinary least square regression model. This thesis finds that the information related to cornerstone investors is positively correlated with price stabilising actions in the aftermarket.
- PublicationQuantitative mri fibre tractography in leukoaraiosis: Analysis of lesional and non-lesional cerebral white matter(2022)Background: Leukoaraiosis was first described as area of hypodensity on CT imaging and on conventional MRI, it is an appear hyperintense on both T2-weighted and fluid attenuation recovery inversion (FLAIR). Both may represent a variety of different pathologies, only some of which are associated with tissue destruction and neuronal disfunction. Diffusion tensor imaging (DTI) MR imaging was based on movement of water molecules in biology tissue. DT imaging was widely used to study microstructural in brain, musculoskeletal and spinal cord. Any change in tissue will affect the water molecules movement that provide microscopy information regarding the tissue which allow detection of abnormalities in early stage. The distinctive features of DT imaging are fiber tractography which give quantitative and qualitative assesment of the nerve fiber in the brain. This study compares the ADC, FA and Fiber density Index value between leukoaraiosis and normal control subjects using 3T MRI system. Methodology: A retrospective study was conducted in Hospital USM, Kota Bharu for 36month duration. This study involves age-matched 34 healthy subjects and 34 Leukoaraiosis patients. All of them had undergone magnetic resonance imaging (MRI) where images were then post-processed and underwent first level analysis to meet the optimum sequence and DTI parameter. Second level analysis were then performed using tractography software by manually drawed region of interest (ROI) at leukoaraiosis area and to compare the parametric value with normal appearing white matter subjects at the same region. For effective result, age-matched comparison with same area of brain regions were chosen for both control subjects and leukoaraiosis patients. FA, ADC, fiber volume and voxel were generate automatically by the software. Statistical analysis was using paired T-test to compare value of both group. Results: The mean of FA value in control and leukoaraiosis group were 0.393 (±0.039) and 0.333 (±0.058) respectively. The mean of ADC value in control and leukoaraiosis group were 0.782 (±0.036) and 0.823 (±0.068) respectively. The mean of FDI value in control and leukoaraiosis group were 1.341 (±0.310) and 1.062 (±0.240) respectively. The different was statistically significant in FA, ADC and FDI value between two group. Conclusion: This study found that there is a statistically difference mean value of FA, ADC and FDI between leukoaraiosis and normal appearing white matter control subject. The ability of MRI‐based fiber tractography to delineate the white matter fibre pathways of the brain non‐invasively has raised possibilities for clinical applications and offers potential used for early detection of white matter integrity, evaluation of white matter severity and progression in the future.
- ItemPembinaan Dan Kesan Modul Terapi Seni Dalam Pengurusan Kemarahan Remaja(Universiti Sains Malaysia, 2021-04)Kajian ini bertujuan untuk membina Modul Terapi Seni Dalam Pengurusan Kemarahan Remaja (TASMAR) dan mengkaji kesan modul tersebut. Kajian ini juga untuk mengenal pasti kesahan dan kebolehpercayaan modul. Nilai kesahan modul adalah 82.28 peratus manakala nilai alpha cronbach’s bagi kebolehpercayaan modul adalah .96. Sampel dikenal pasti melalui kaedah persampelan bertujuan. Sampel terdiri daripada remaja yang mendapat skor tahap kemarahan 76-100 dalam ujian State-Trait Anger Expression Inventory-2 Child and Adolescent (STAXI-2 C/A). Bagi melihat kesan modul, rekabentuk kajian kuasi eksprimen digunakan dengan gabungan kaedah kuatitatif dan kuanlitatif. Keputusan kuatitatif mendapati terdapat perbezaan yang signifikan kesan modul terhadap kemarahan remaja, nilai t=2.83, df=71, p=0.00 (p<.05). Kesan modul terhadap pengurusan kemarahan remaja berdasarkan jantina menunjukkan perbezaan yang signifikan, nilai t=5.86, df=70, p=.000 (p<.05). Seterusnya, terdapat perbezaan yang signifikan kesan modul terhadap pengurusan kemarahan remaja berdasarkan masa, nilai t6.54, df=71, p=.000 (P>.05). Secara kuantitatif, modul berkesan dalam pengurusan kemarahan terhadap remaja lelaki dan perempuan. Modul juga berkesan secara kualitatif dengan hasil dapatan temu bual yang membentuk tema-tema yang menunjukkan kesan positif modul terhadap remaja iaitu memberi pengetahuan baru, meluahkan kemarahan, menyembuhkan emosi, merubah diri dan memberi motivasi. Impikasi kajian ini, remaja dapat diberikan kemahiran mengatasi kemarahan. Hal ini dapat mengurangkan kesan negatif kemarahan seperti salah laku, jenayah serta masalah kesihatan mental dan fizikal. Kajian ini juga memberi sumbangan ilmu dalam penghasilan modul intervensi kaunseling menggunakan pendekatan terapi seni.