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Studies of corrugated antipodal Vivaldi wideband antenna with notched band and rectenna integration
Get PDFA wideband rectenna based on a Corrugated Antipodal Vivaldi Antenna (AVA) with a notched band is proposed
for energy harvesting applications. The antenna performance is studied parametrically by varying the corrugated and rectangular spiral slot (RSS) structures and also by integrating the antenna with a rectenna for energy harvesting applications. The AVA rectenna achieves an S₁₁ of less than -10 dB from 2.38 GHz to beyond 20 GHz. An AVA with two corrugations at the lower position of the radiator increases the bandwidth by 300 MHz compared to an AVA without corrugation. At 2 GHz, AVAs with three and four corrugations exhibit a directivity of 5.73 dBi, compared to 2.9 dBi for an AVA without corrugation. Increasing the corrugation depth enhances the gain, ranging from 3.05 dBi to 9 dBi. The notched band shifts to lower frequencies as the spiral strip slot lengthens, so we can set the desired notched band by adjusting the length and position of the RSS. Furthermore,
Integration of a rectangular spiral slot (RSS) enables tunable notched bands, providing flexibility to reject interference from unwanted frequency ranges. The agreement between simulation and measurement confirms that the proposed AVA rectenna is also a strong candidate for wideband energy harvesting applications
Quantitative study on the combustion characteristics of water-in-oil emulsion droplets using high-speed imaging technique
No full textUnderstanding the combustion characteristics of fuel droplets is essential for optimizing combustion processes in internal combustion engines and industrial burners. Fuel droplets govern initial fuel-air mixing, vaporization, and combustion, making their study crucial. While previous research suggests that elevated water content in emulsion droplets can lead to increased burning rates, the underlying mechanism remains unclear. Potential contributors including micro-explosions, puffing, sub-droplet ejections, and surface distortions, all of which impacts the burning rates of emulsion fuel. This study aims to investigate the combustion characteristics based on the burning rate and liquid stability of water-in-diesel (WD) and ethanol-in-diesel (ED) emulsion fuels across varying temperatures. High-speed imaging and combustion analysis revealed that WD emulsions exhibit higher burning rates, with evaporation rates increased by 87.35% for WD10, 120.46% for WD20, and 130.66% for WD30 as the temperature rises from 250°C to 350°C. In contrast, ED emulsions showed smaller increases, with rates of 12.33% for ED10, 9.97% for ED20, and 10.31% for ED30 under the same conditions. WD emulsions also experienced larger droplet expansion (D² = 3.3) compared to ED emulsions (D² = 2.97) at 250°C. These findings suggest that WD emulsions, due to their volatile water content, undergo more chaotic combustion characterized by puffing and micro-explosions, while ED emulsions provide more stable combustion behaviour due to the miscibility of ethanol and diesel, which reduces the need for emulsification. This study provides critical insights into the combustion dynamics of WD and ED emulsions, highlighting their potential to improve combustion efficiency and reduce emissions. The results underscore the importance of emulsification in stabilizing combustion for WD fuels and the role of temperature and additive volume in influencing combustion behaviour. These findings contribute to the development of sustainable fuel compositions for industrial applications
Torque ripple minimization of rotating pole piece concentric magnetic gear using rotor skewing and pole piece modification
Get PDFRotating pole piece magnetic gear (RPMG) produces higher average torque than the conventional concentric magnetic gear (CMG). However, it also exhibits a higher torque ripple at the outer rotor as a result of switching of the rotating
component from the outer pole pair (OPP) to the ferromagnetic pole piece (FMP). This paper explores a torque ripple suppression strategy through rotor skewing
applied to the inner pole pair (IPP), outer pole pair (OPP), and ferromagnetic pole piece (FMP). Additionally, this study evaluates the impact of four distinct FMP shapes on the RPMG torque profile. Two gear ratio structures were tested at 4.33 and 5.66 ratio using 2D JMAG Designer finite element software. When skewing was performed on the IPP, it is observed that the inner torque ripple was reduced in both gear ratios when compared to the original structure with a slight drop in average torque for both rotors and gear ratios. Similarly, when smooth shape FMP was used in RPMG, it produced nearly the same average torque and slightly
minimized the torque ripple in both gear ratios versus the original structure. The inner torque ripple was reduced to 2.9% at a 4.33 gear ratio and 4.1% at a 5.66 gear ratio, compared to the original structure. This improvement resulted in a slight average torque decrease of 1-2.5% across both rotors and gear ratios. Theoretically, simulation results have shown that rotor skewing, and FMP shape modification could minimize the torque ripple in RPMG especially at the inner rotor with moderately declined average torque for EV application where minimizing torque ripple is essential for smoother driving experience and reducing mechanical stress on components
Analysis of cascaded H-Bridge multilevel inverters using SPWM with multi-sinusoidal reference
Get PDFMultilevel inverters have become the preferred choice for medium voltage and high-power applications due to their superior waveform quality, reduced stress on switching components, and overall enhanced performance. Among
these, the cascaded H-bridge inverter stands out for its simpler control and modulation techniques, as well as its greater efficiency compared to other multilevel inverter topologies. This paper presents the design and performance evaluation of a cascaded H-bridge multilevel inverter (CHMI)
for five, seven, nine, eleven, thirteen, and fifteen levels, utilizing sinusoidal pulse width modulation (SPWM) in MATLAB Simulink. The proposed technique, the multi-sinusoidal reference, is implemented by comparing multiple sinusoidal wave signals with a carrier triangular signal, with the resulting comparison pulses used to control the inverter's switching. The output results indicate that as the number of levels in multilevel inverters increases, the total harmonic distortion (THD) decreases, and the output voltage improves
Maqasid syariah tonggak jaminan sistem kawalan makanan halal
Get PDFDalam dunia yang semakin kompleks, pemahaman mengenai ilmu Maqasid Syariah menjadi semakin penting, terutama dalam konteks industri makanan halal. Dengan kesedaran untuk berkongsi ilmu, karya ini dihasilkan untuk mempromosikan nilai halal, mendukung pemahaman serta menyokong pembangunan industri makanan halal. Buku "Maqasid Syariah Tonggak Jaminan Sistem Kawalan Makanan Halal" ini diinspirasikan daripada dapatan kajian lapangan yang telah dijalankan oleh penulis bersama pasukan penyelidik. Buku ini membawakan analisis tentang peranan Maqasid Syariah dalam memperkukuh sistem kawalan makanan halal. Pembangunan industri makanan halal di Malaysia ditunjangi oleh dasar dan strategi yang berkesan. Walaupun begitu, industri ini masih berdepan dengan kepincangan yang memerlukan perhatian terutamanya dari aspek kawalan. Sistem kawalan makanan halal adalah komponen penting dalam memastikan integriti dan kualiti produk makanan halal. Dari perspektif teori, penulis mengupas bagaimana prinsip Magasid Syariah berperanan memberi panduan dalam pelaksanaan proses kawalan terhadap sesuatu produk makanan dan minuman yang dilabelkan halal. Melalui kajian empirikal, buku ini menggariskan prinsip Magasid Syariah dan formula yang relevan untuk diterjemahkan dalam pelaksanaan kawalan makanan halal. Namun, cabaran seperti integriti pengusaha, pengetahuan pengendali, dan kesediaan pematuhan memerlukan strategi pengurusan yang berkesan untuk memastikan industri halal dapat berkembang dengan mampan dan memenuhi tuntutan masyarakat
Enhancement of flat spiral antenna for non-radiated inductive wireless energy transfer
Get PDFThe book, "Enhancement of Flat Spiral Antenna for Non-Radiated Inductive Wireless Energy Transfer", offers a comprehensive study of inductive wireless energy transfer (WET) systems, emphasizing the enhancement of transfer efficiency through optimum flat spiral antenna designs. The primary methodology of the book focuses on theoretical modelling, various technique, simulation, and experimental validation to improve antenna performance in WET applications. The book emphasizes the critical importance of antenna shape, material, distance and design structure in improving transfer efficiency. The improved flat spiral antenna demonstrates significant enhancements in energy transfer and size reduction, crucial for mobile and compact devices. Through the modification of the number of turns, loop gap, and material selection, the author achieves significant enhancements in efficiency without requiring larger antennas. The book offers significant improvements to the advancement of inductive WET systems, namely in improving energy transfer efficiency while preserving compact and mobile-friendly designs. Ideal for researchers, engineers, and students, this book helps readers understand the fundamental principles and advanced techniques in wireless energy transfer
Graphene based Perovskite solar cells : The rise of emerging photovoltaic technology
Get PDFGraphene-Based Perovskite Solar Cells: The Rise of Emerging Photovoltaic Technology explores the transformative potential of graphene in revolutionising solar energy. This book examines the fundamental principles of perovskite solar cells (PSCs), their challenges, and how graphene's unique properties can enhance performance, efficiency, and stability. By addressing issues such as material degradation, improving charge transport, and enabling flexible solar cells, graphene's role in PSCs is set to drive the next generation of renewable energy solutions. Written for professionals and enthusiasts, the book highlights the latest advancements in graphene integration, offering insights into the industrialisation and commercialisation of PSC technology. Whether you are a researcher, engineer, or energy enthusiast, this comprehensive resource provides an in-depth understanding of the future of solar energy
Resilient supply chains in Malaysia's manufacturing sector: A comparative analysis of priority industries affected by COVID-19
Get PDFThe COVID-19 pandemic exposed vulnerabilities within global supply chains, with Malaysia’s manufacturing sector, a cornerstone of the nation’s economy, experiencing significant disruptions. This study explores the interplay between supply chain risk management (SCRM), supply chain resilience (SCR), and sustainability efforts (SE) within the context of Malaysia’s priority manufacturing sectors—namely aerospace, chemicals, electrical and electronics (E&E), pharmaceuticals, and medical devices. Employing a quantitative research approach, data were collected from 360 firms, and the hypothesized relationships were analyzed using structural equation modeling. The findings confirm that effective SCRM practices significantly enhance SCR across all sectors, with the E&E industry exhibiting the strongest relationship due to its reliance on globalized networks. Furthermore, SCR positively influences supply chain performance (SCP), highlighting its critical role in maintaining operational efficiency, delivery reliability, and customer satisfaction during disruptions. The study also reveals a nuanced moderating role of SE on the SCRM-SCR relationship, with significant effects observed in the aerospace sector, underscoring the sector-specific dynamics of resilience-building efforts. This research offers one of the first empirical assessments of these dynamics across Malaysia’s most strategic manufacturing industries, providing sector-specific insights aligned with the country’s New Industrial Master Plan 2030. The findings offer valuable guidance for Malaysian businesses and policymakers seeking to enhance supply chain robustness, sustainability, and competitive advantage in preparation for future disruptions
Finding new similarities measures for Type-II Diophantine neutrosophic interval valued soft sets and its basic operations
No full textThe Type-II Diophantine neutrosophic interval valued soft set (Type-II DioNSIVSS) and related similarity measure are presented in this study. An extension of the neutrosophic interval valued soft set (NSIVSS) and the Diophantine fuzzy soft set is the Type-II DioNSIVSS. The suggested measure for Type-II DioNSIVSS assessment. We support a method of solving the problem using the Type-II soft set model. To demonstrate
how they can be applied to successfully handle uncertainty-related challenges, illustrative examples are given
Effect of adding al2o3ceramic in wire arc additive manufacturing 308LSi stainless steel
No full textWire Arc Additive Manufacturing (WAAM) is a process that allows for efficient in-situ production of components or remanufacturing based on its capabilities to produce at a greater rate of deposition at a lower cost. However, WAAM components suffer from heat dissipation during the deposition process that causes the growth of coarse columnar grains resulting in poor mechanical properties that will limit industrial applications. Thus, this research investigates the role of introducing Al2O3 ceramic powder particle inoculants to the AWS A5.9 ER308LSi stainless steel wall structure to enhance the mechanical performance capabilities by refining the grain process. During deposition, the Al2O3 ceramic powder particle was manually added to each layer when the temperature drops to 150ᵒC. A complete series of tensile testing was executed to bridge those knowledge gaps. WAAM walls were fabricated and the microstructure of the sample were analysed. The results revealed that the highest tensile strength of WAAM SS308LSi components recorded at 560 MPa in the deposition direction, which increased by 6% compared to the non-inoculated sample. The improvement was due to the success of grain refinement and heterogeneous nucleation. The study demonstrates the potential of the technique to improve the mechanical properties and microstructure during WAAM components fabrication or remanufacturing