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RISS 인기검색어
- 검색키워드
- 저자 : Shakeel Akram (검색결과 4 건)
- 무료
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Shakeel Akram,Guangning Wu,GuoQiang Gao,Yang Liu 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.5
With the continuous development in insulation of electrical equipment design, the reliability of the system has been enhanced. However, in the manufacturing process and during operation under continues stresses introduce local defects, such as voids between interfaces that can responsible to occurrence of partial discharge (PD), electric field distortion and accumulation of charges. These defects may lead to localize corrosion and material degradation of insulation system, and a serious threat to the equipment. A model of three layers of PI film with air gap is presented to understand the influence of interface and voids on exploitation conditions such as strong electrical field, PD activity and charge movement. The analytical analysis, and experimental results are good agreement and show that the lose contact between interfaces accumulate more residual charges and in consequences increase the electric field intensity and accelerates internal discharges. These residual charges are trapped charges, injected by the electrodes has often same polarity, so the electric field in cavities increases significantly and thus partial discharge inception voltage (PDIV) decreases. Contrary, number of PD discharge quantity increases due to interface. Interfacial polarization effect has opposite impact on electric field and PDIV as compare to void.
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Akram, Shakeel,Wu, Guangning,Gao, GuoQiang,Liu, Yang The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5
With the continuous development in insulation of electrical equipment design, the reliability of the system has been enhanced. However, in the manufacturing process and during operation under continues stresses introduce local defects, such as voids between interfaces that can responsible to occurrence of partial discharge (PD), electric field distortion and accumulation of charges. These defects may lead to localize corrosion and material degradation of insulation system, and a serious threat to the equipment. A model of three layers of PI film with air gap is presented to understand the influence of interface and voids on exploitation conditions such as strong electrical field, PD activity and charge movement. The analytical analysis, and experimental results are good agreement and show that the lose contact between interfaces accumulate more residual charges and in consequences increase the electric field intensity and accelerates internal discharges. These residual charges are trapped charges, injected by the electrodes has often same polarity, so the electric field in cavities increases significantly and thus partial discharge inception voltage (PDIV) decreases. Contrary, number of PD discharge quantity increases due to interface. Interfacial polarization effect has opposite impact on electric field and PDIV as compare to void.
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Muhammad Shoaib Bhutta,Tang Xuebang,Shakeel Akram,Chen Yidong,Xiancheng Ren,Muhammad Fasehullah,Ghulam Rasool,Muhammad Tariq Nazir 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-
Graphene and its oxides are the most extensively studied, fascinating 2-dimensional Sp2 carbon hybridizedmaterials. Due to its superior and excellent thermal conductivity, it is considered to be a practicalsolution for the thermal dissipation of electric machines electronic components. Furthermore, grapheneoxide invariably reduces electrical insulation capability, which is inappropriate for electrical machinesrequiring low electrical and high thermal conductivity. Therefore, we have created 2D-3D hybrid grapheneoxide (GO)-diamond (DM) micro-composite polyimide (PI) films for high temperature and electricallyinsulated environments of electric machines such as motors and generators. With a modest fillingcharge of 10 wt% GO with 10% diamond (DM), the maximum thermal conductivity of 1.83 Wm-1K1 isachieved for polyimide micro composite and is almost 11 times higher than that of pristine PI films. The 10% PI/GO/DM micro composite films also show lower electrical conductivity than other samples. Hybrid fillers with high thermal and low electrical conductivities are responsible for synergistic improvementsin experimental results.
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Siyal Sajid Hussain,Javed Muhammad Sufyan,Ahmad Awais,Sajjad Muhammad,Batool Saima,Khan Abdul Jabbar,Akram Shakeel,Alothman Asma A.,Alshgari Razan A.,Najam Tayyaba 한국물리학회 2021 Current Applied Physics Vol.31 No.-
The development of smart structured cathode materials for supercapacitors (SCs) has sparked tremendous interest. However, the appropriate design to achieve high capacitance and energy density-based cathode materials remains a major problem for energy storage systems. This article describes the effective synthesis of selfsupported 3D micro-flowers composed of ultrathin nanowires array of Co3O4 on Ni foam (NF) using hydrothermal conditions (Co3O4@NF). The mesoporous Co3O4@NF with a high surface area, providing a rich active state for the Faraday redox reaction and increasing the diffusion rate of the electrolyte ions. The optimized Co3O4@NF-16h electrode exhibited supreme electrochemical performance by delivering a high specific capacitance of 1878, (1127) and 1200 (720 C g 1) F g 1 at 1.0 and 20 A g 1, respectively. The Co3O4@NF electrode retained good capacitance stability of 91% over 10000 cycles at 20 A g 1 with excellent rate-performance of 67% at 20 folded high current values. The obtained results for the Co3O4@NF electrode are presented the enhanced pseudocapacitive performance, indicating the substantial potential for high-performance supercapacitor applications.
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