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PublicationEffect of multi-unit and multi-type DG installation using integrated optimization technique in distribution power system planning(Elsevier, 2024)With the rise in load demand, improving the voltage profile and reducing line loss is vital to ensure reliable power delivery to the customer. However, increasing power plant generation capacity is limited by environmental and economic factors, requiring a careful assessment of locally optimal options. Distributed Generation (DG) installation into the electricity grid is one of the reliable remedial actions to ensure a smooth power delivery. Installation of DG requires an optimization process to identify the appropriate placement and sizing. Inaccurate sizing and placement of the DG installation may result to over-compensation or under-compensation phenomena. This paper proposes a novel approach termed the Integrated Immune Moth Flame Evolutionary Programming technique (IIMFEP) for optimizing the installation of DG sources in distribution systems. It handles various scenarios, including multi-DG single-type and multi-DG multi-type installations, with the main objective of minimizing power loss in the system. This technique employs a hybrid approach that combines elements of immune algorithms, moth flame optimization, and evolutionary programming to achieve more accurate and efficient results. Two cases were considered in this study termed Case 1 and Case 2. Results in Case 1 discovered that the optimal sizing and placement of four Type III DGs exhibit the lowest power loss worth 2.74 kW (98.78 % reduction) for the 69-Bus RDS, while for the 118-Bus RDS the power loss is 319.89 kW (75.36 % reduction). In Case Study 2, the combination of DG Types I and III provided the highest power loss reduction. With one DG Type I and two DG Type III units installed, power loss was reduced by 97.15 % to 6.41 kW for the 69-Bus RDS and by 62.01 % to 493.21 kW for the 118-Bus RDS. The proposed IIMFEP managed to alleviate the setback experienced in the traditional EP, AIS and MFO which found to be stuck at local optimum. The IIMFEP method is compared to Moth Flame Optimization, Artificial Immune System and Evolutionary Programming and validated using the IEEE 69-Bus and 118-Bus Radial Distribution Systems, resulting in outstanding performance.
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PublicationComputational study of the structural, mechanical, electronic, optical and thermal properties of BaLiX (X =P, As, Sb) perovskites(Elsevier, 2024-11)This study explores the structural, optical, mechanical, electronic, and thermal characteristics of ionic semiconductor compounds BaLiX (X = P, As, Sb) using Density Functional Theory (DFT). A comprehensive analysis of BaLiX (X = P, As, Sb) is conducted, proving that the estimated and observed lattice parameters coincide well and confirming mechanical stability through elastic stiffness constants. Electronic band structures reveal direct bandgap semiconductor properties with values of 0.70 eV, 0.30 eV, and 0.95 eV for BaLiP, BaLiAs, and BaLiSb, respectively, suggesting specific applications such as mid-infrared photodetectors, terahertz devices, and near-infrared sensors. Optical property analyses, including energy loss function, reflectivity, refractive index, and absorption coefficient, highlight the potential of these materials for optoelectronic and photovoltaic applications. Despite elastic anisotropy, optical anisotropy remains minimal. The materials exhibit potential for use as thermal barrier coatings (TBC) due to their comparatively lower Debye temperature (D), minimum thermal conductivity (Kmin) and lattice thermal conductivity (kph). Moreover, heat capacity calculations and thermal coefficient of expansion are also calculated.
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PublicationAll solution processable OTFT-Based on direct-written printing method towards flexible electronics applications(Semarak Ilmu Publishing, 2024)Development of organic electronics, particularly organic thin film transistors (OTFTs), have been centred of discussion among researchers due to their potential uses in flexible electronics applications. Conventionally, an inkjet printing method has been deployed to fabricate the OTFTs due to its simplicity in fabrication steps and applicability to diverse substrates and solution-processable materials. Nonetheless, this technique has a major drawback which requires low viscosity materials to prevent clogging issue at the printer’s nozzle. This in return limits the material selections and requires additional steps i.e. modification of the selected materials to fit the printer’s requirement or in other words, to avoid clogging at the nozzle. Therefore, this paper proposes a method to fabricate a bottom gate bottom contact (BGBC) OTFT by using a direct-write printing technique which is compatible with a commercial conductive ink that can be directly used without any further modification. This technique does not compromise the fabricated devices overall performance and can fabricate the devices up to micrometre scale. The proposed OTFT achieved a saturation mobility of 4.28x10-5 cm2/Vs, a threshold voltage of -0.4 V, an on/off current ratio of 102, and a subthreshold swing of 10 V/dec with overall fabrication temperature is less than 150 ℃, hence, makes it suitable for flexible electronics applications.
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PublicationAutomatic paddy planthopper detection and counting using faster R-CNN(MDPI, 2024-09-10)Counting planthoppers manually is laborious and yields inconsistent results, particularly when dealing with species with similar features, such as the brown planthopper (Nilaparvata lugens; BPH), whitebacked planthopper (Sogatella furcifera; WBPH), zigzag leafhopper (Maiestas dorsalis; ZIGZAG), and green leafhopper (Nephotettix malayanus and Nephotettix virescens; GLH). Most of the available automated counting methods are limited to populations of a small density and often do not consider those with a high density, which require more complex solutions due to overlapping objects. Therefore, this research presents a comprehensive assessment of an object detection algorithm specifically developed to precisely detect and quantify planthoppers. It utilises annotated datasets obtained from sticky light traps, comprising 1654 images across four distinct classes of planthoppers and one class of benign insects. The datasets were subjected to data augmentation and utilised to train four convolutional object detection models based on transfer learning. The results indicated that Faster R-CNN VGG 16 outperformed other models, achieving a mean average precision (mAP) score of 97.69% and exhibiting exceptional accuracy in classifying all planthopper categories. The correctness of the model was verified by entomologists, who confirmed a classification and counting accuracy rate of 98.84%. Nevertheless, the model fails to recognise certain samples because of the high density of the population and the significant overlap among them. This research effectively resolved the issue of low- to medium-density samples by achieving very precise and rapid detection and counting.
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PublicationDesign of buck converter based on maximum power point tracking for photovoltaic applications(Semarak Ilmu Publishing, 2024)The MPPT converter ensures that the PV system operates at the maximum power point, which is the point where the solar panels can generate the most power. This is done by adjusting the voltage of the output. The converter uses a DC-DC conversion process and can be implemented using a buck converter circuit. This project uses a buck converter to adapt the voltage to its appropriate value to reach a maximal power extraction. This power converter can be designed in several ways. This involves employing a typical power converter design to create the power converter in the MPPT converter. Furthermore, the inductance and capacitance derivation for the MPPT converter is insufficient, making determining the inductance and capacitance unfeasible. Hence, this study focuses on designing the buck converter for MPPT application and tracking the maximum power using the Perturb and Observe (P&O) method. This system will be implemented by using MATLAB/Simulink. To design the MPPT buck converter, several parameters need to be considered and derived. This project finds that the MPPT buck converter that has been designed can track the maximum power from 900 W/m2 to 1100 W/m2 of irradiance. The design of the MPPT buck converter using the P&O method is fairly accurate, and the accuracy of tracking the maximum power is around 98%.