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Improving the polarisation and depolarisation current measuring method to avoid ground wire interference

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High Voltage 2022年第5期7卷 847-855页

作者： Fan Yang Kai Zhou Shakeel Akram muhammad tariq nazir School of Electrical Engineering and Electronic Information Xihua UniversityChengduChina College of Electrical Engineering Sichuan UniversityChengduSichuanChina School of Electrical Engineering and Telecommunications University of New South WalesSydneyNew South WalesAustralia

The ground wire is significantly interfered by the current above 1μA in the industrial field during the traditional polarisation and depolarisation current(PDC)*** paper explains a method to test PDC from high-voltage wire using a principle of equipotential picoammeter,which is completely isolated from the ground wire and connected in series with the high voltage *** this method,a device is designed with a multi-range automatic switching *** device can automatically switch the test range current from 1 pA to 10 mA with a resolution of 1 *** demonstrate the device and effectiveness of this new method,the traditional and the proposed new device are used to test the PDC of cable samples in the laboratory as well as in an industrial *** is worth noting that there is almost no interference on the Earth wire in the laboratory environment but massive interference in the industrial environment using a traditional method of PDC measurement from ground or Earth *** new method of high-voltage testing can efficiently eliminate the interference and accurately measure PDC in a strong industrial interference ***,the wiring of this new method and device is relatively simple,which is convenient for industrial applications.

关键词： ground polar method

Significantly enhanced flashover voltage of epoxy in vacuum by graded surface roughness modification

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High Voltage 2023年第5期8卷 997-1010页

作者： Inzamam Ul Haq Feipeng Wang Shakeel Akram Muneeb Ahmed muhammad tariq nazir State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjingChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina School of Engineering RMIT UniversityMelbourneVictoriaAustralia

The flashover strength of epoxy(EP)insulations in the High voltage direct current applications of future energy grids can be improved by tailoring their surface *** work aims to improve the DC surface flashover characteristics of EP after being treated with sandpaper of different *** with virgin EP and homogenously modified EP considering varying surface roughness(R_(a)=0.54,3.16,5.24,and 8.35μm)are *** experimental characterisations,such as water contact angle,surface intrinsic conductivity,surface voltages,flashover strength,and trap distributions are conducted and evaluated to analyse the difference between virgin and treated ***,based on the obtained experimental results of homogenously treated EP and theoretical analysis,the concept of surface functionally graded materials(SFGMs)is put *** flashover voltages of homogenously treated EP are augmented significantly compared to virgin EP regardless of the voltage polarity and enhanced by enhancing the surface *** sample T_(Model‐C) with SFGM design shows a 45.02%and 43.75%improvement in the negative and positive flashover voltages than that of the virgin *** the end,COMSOL simulations are conducted to justify the experimental findings and to analyse the difference between virgin and modified samples in terms of electric field distribution.

关键词： flash graded roughness

Tracking,erosion and thermal distribution of micro-AlN+nano-SiO_(2) co-filled silicone rubber for high-voltage outdoor insulation

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High Voltage 2018年第4期3卷 289-294页

作者： muhammad tariq nazir Bao Toan Phung Shihu Yu Yuanyuan Zhang Shengtao Li School of Electrical Engineering and Telecommunications University of New South Wales SydneyAustralia State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anPeople's Republic of China

Thermal depolymerisation induced tracking and erosion of polymeric insulators is one of the key insulation failure modes and this process adversely affects the reliability of power delivery *** study reports the tracking,erosion and thermal distribution of micron-AlN and micron-AlN+nano-SiO_(2)co-filled silicone rubber composites.A tracking-erosion model is presented to explain how the co-filled set of particles directly affects such *** nitride(AlN:5-10μm)and silica(SiO_(2):20 nm)particles were procured for fabricating test *** inclined plane test according to IEC 60587 was carried out using tracking voltage method 2 with an initial applied voltage of 3 kV and a ramping rate of 0.25 kV/h over the duration of 240 *** results show co-filled composites exhibit significantly lower physical tracking and erosion as compared to micron-AlN filled *** accumulation and average leakage current in co-filled composites are found noticeably lower than micron-filled ***,the increased surface area of the combined co-filled particles in the composites provides better scattering and reduce secondary electron *** may impede the release of high energy causing thermal degradation.

关键词： composites filled rubber

Impact of Accelerated Ultraviolet Weathering on Polymeric Composite Insulators Under High Voltage DC Stress

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CSEE Journal of Power and Energy Systems 2022年第3期8卷 922-932页

作者： Israr Ullah muhammad Amin Haider Hussain M.tariq nazir Faculty of Electrical Engineering Ghulam Ishaq Khan Institute of Engineering Sciences and TechnologyTopiSwabiKPK23460Pakistan School of Mechanical and Manufacturing Engineering University of New South Wales SydneyNSW 2052Australia School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW 2052Australia

This study investigates the weatherability of room temperature vulcanized(RTV)silicone rubber(SiR)and epoxybased material specimens with a composition of different nano and micro fillers against the collegial effects of high voltage DC,UV and temperature *** power transmission over long distances via HVDC is considered an economic option these days,so to ensure the system reliability,it is also critical to investigate these insulators under DC stress along with other environmental stresses(especially UV and temperature).For experimentation,composite samples *** epoxy(NE),epoxy with 15%micro SiO_(2)(EMS),epoxy with 5%nano SiO_(2)(ENS),neat SiR(NS),SiR with 15%micro SiO_(2)(SMS)and SiR with 5%nano SiO_(2)(SNS)are fabricated and subjected to accelerated aging in a weather chamber for 3,360 *** reveal that SMS and SNS offer better hydrophobic behavior followed by *** noticeable surface discoloration in the form of whitish shade with minor blackish spots is found in the case of SMS,while remaining samples also showed considerable color *** electron microscopy(SEM)and Fourier Transform Infrared Spectroscopy(FTIR)results showed that SNS and SMS presented quite excellent resistance to the exposure of *** and weight of all specimens are evaluated throughout the experiment and particularly for the water immersion ***,leakage current analysis indicated that SNS and SMS revealed high leakage current suppression compare to other *** indicate that SNS and SMS showed enhanced resistance against UV weathering under high voltage direct current stress.

关键词： Aging composites DC stress epoxy insulator UV SiR

Optimization Based on Convergence Velocity and Reliability for Hydraulic Servo System

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Chinese Journal of Aeronautics 2009年第4期22卷 407-412页

作者： muhammad Babar nazir School of Automation Science and Electrical Engineering Beijing University of Aeronautics and Astronautics

This article presents an optimal hybrid fuzzy proportion integral derivative （HFPID） controller based on combination of proportion integral derivative （PID） and fuzzy controllers, by which the parameters could be evaluated by global optimization either in convergence velocity or in convergence reliability. Focusing on the nonlinear factors of hydraulic servo system, this article takes advantage of PID and fuzzy logic controller integrated with scaling factors to acquire precise tracking performances. To further improve the performances, it provides new developed optimization with rapid convergence to attain reliable approach probability. Focusing on the performance indictors of evolutionary algorithm, this article presents a new technique to predict reliability of the optimization algorithm. Statistics authenticates the effectiveness and robustness of the optimization. Further, many simulation and experimental results indicate that the optimal HFPID could acquire perfect immunity against parametric uncertainties with external disturbance.

关键词： adaptive control system novel evolutionary algorithm hydraulic control equipment convergence velocity convergencereliability optimization

An Ensemble of Optimal Deep Learning Features for Brain Tumor Classification

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Computers, Materials & Continua 2021年第11期69卷 2653-2670页

作者： Ahsan Aziz muhammad Attique Usman tariq Yunyoung Nam muhammad nazir Chang-Won Jeong Reham R.Mostafa Rasha H.Sakr Department of Computer Science HITEC UniversityTaxilaPakistan College of Computer Engineering and Sciences Prince Sattam Bin Abdulaziz UniversityAl-KhrajSaudi Arabia Department of ICT Convergence Soonchunhyang UniversityAsanKorea Medical Convergence Research Center Wonkwang UniversityIksanKorea Department of Information Systems Faculty of Computers and Information SciencesMansoura UniversityMansouraEgypt Department of Computer Science Faculty of Computers and Information SciencesMansoura UniversityMansouraEgypt

Owing to technological developments,Medical image analysis has received considerable attention in the rapid detection and classification of *** brain is an essential organ in *** tumors cause loss of memory,vision,and *** 2020,approximately 18,020 deaths occurred due to brain *** cases can be minimized if a brain tumor is diagnosed at a very early *** vision researchers have introduced several techniques for brain tumor detection and ***,owing to many factors,this is still a challenging *** challenges relate to the tumor size,the shape of a tumor,location of the tumor,selection of important features,among *** this study,we proposed a framework for multimodal brain tumor classification using an ensemble of optimal deep learning *** the proposed framework,initially,a database is normalized in the form of high-grade glioma(HGG)and low-grade glioma(LGG)patients and then two pre-trained deep learning models(ResNet50 and Densenet201)are *** deep learning models were modified and trained using transfer ***,the enhanced ant colony optimization algorithm is proposed for best feature selection from both deep *** selected features are fused using a serial-based approach and classified using a cubic support vector *** experimental process was conducted on the BraTs2019 dataset and achieved accuracies of 87.8%and 84.6%for HGG and LGG,*** comparison is performed using several classification methods,and it shows the significance of our proposed technique.

关键词： Brain tumor data normalization transfer learning features optimization features fusion

Image Authenticity Detection Using DWT and Circular Block-Based LTrP Features

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Computers, Materials & Continua 2021年第11期69卷 1927-1944页

作者： Marriam Nawaz Zahid Mehmood Tahira nazir Momina Masood Usman tariq Asmaa Mahdi Munshi Awais Mehmood muhammad Rashid Department of Computer Science University of Engineering and TechnologyTaxila47050Pakistan Department of Computer Engineering University of Engineering and TechnologyTaxila47050Pakistan College of Computer Engineering and Sciences Prince Sattam bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia College of Computer Science and Engineering University of JeddahJeddah21577Saudi Arabia Department of Computer Engineering Umm Al-Qura UniversityMakkah21421Saudi Arabia

Copy-move forgery is the most common type of digital image manipulation,in which the content from the same image is used to forge *** manipulations are performed to hide the desired ***,forgery detection methods are required to identify forged *** have introduced a novel method for features computation by employing a circular block-based method through local tetra pattern(LTrP)features to detect the single and multiple copy-move attacks from the *** proposed method is applied over the circular blocks to efficiently and effectively deal with the post-processing *** also uses discrete wavelet transform(DWT)for dimension *** obtained approximate image is distributed into circular blocks on which the LTrP algorithm is employed to calculate the feature vector as the LTrP provides detailed information about the image content by utilizing the direction-based relation of central pixel to its ***,Jeffreys and Matusita distance is used for similarity *** the evaluation of the results,three datasets are used,namely MICC-F220,MICC-F2000,and *** the qualitative and quantitative analysis shows that the proposed method exhibits state-of-the-art performance under the presence of post-processing operations and can accurately locate single and multiple copy-move forgery attacks on the images.

关键词： Copy-move forgery discrete wavelet transform LTrP features image forensic circular blocks

Thermal Decomposition Kinetics of Some Di- and Triorganotin（IV） Carboxylates Derived from para-Nitrophenylethanoic Acid

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Chinese Journal of Chemistry 2011年第7期29卷 1359-1365页

作者： Danish, muhammad Ahmad, nazir Ali, Saqib muhammad, Niaz Department of Chemistry University of Gujrat Hafiz Hayat Campus Gujrat-50700 Pakistan Department of Chemistry University of Sargodha Srgoadha 40100 Pakistan Department of Chemistry Quaid-i-Azam University Islamabad-45320 Pakistan

Thermogravimetric （TG） investigations of organotin（IV） carboxylates with the general formula RmSnL4-m （where R=CH3, C2H5, n-C4H9, C6H5, cyclo-C6H11, n-C8H17, m=2, 3, and L=para-nitrophenylethanoate anion） have been performed. Derivative thermogravimetry （DTG） and differential thermal analysis （DTA） techniques, Horowitz-Metzger method and the fundamental thermodynamic relations are used to evaluate the thermokinetic pa- rameters of each thermal degradation pattern. Results reveal that the thermal stability is functional to Sn--C and Sn--O bonds. In the case of R2SnL2, activation energy, reaction order and pre-exponential factor associated with the bulk degradation processes increase as the alkane chain length increases. Hence, Oct2SnL2 is thermally more stable than Bu2SnL2, which in turn is more resistant to thermal dissociation than Et2SnL2. The same phenomenon is not observed for R3SnL compounds because their degradation is highly irregular. Furthermore, R2SnL2 has larger values of kinetic parameters than those of corresponding triorganotin（IV） para-nitrophenylethanotes. Thermodynamic parameters of these compounds also reinforce the above facts.

关键词： organotin(IV) caroxylate thermogravimetry decomposition kinetics activation energy thermodynamics

3D Kronecker Convolutional Feature Pyramid for Brain Tumor Semantic Segmentation in MR Imaging

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Computers, Materials & Continua 2023年第9期76卷 2861-2877页

作者： Kainat nazir Tahir Mustafa Madni Uzair Iqbal Janjua Umer Javed muhammad Attique Khan Usman tariq Jae-Hyuk Cha Medical Imaging and Diagnostics Lab NCAIDepartment of Computer ScienceCOMSATS University IslamabadIslamabad44000Pakistan Department of Electrical and Computer Engineering COMSATS University IslamabadWah CampusWahPakistan Department of Computer Science HITEC UniversityTaxilaPakistan Department of Management Information Systems College of Business AdministrationPrince Sattam Bin Abdulaziz UniversityAl-Kharj16273Saudi Arabia Department of Computer Science Hanyang UniversitySeoul04763Korea

Brain tumor significantly impacts the quality of life and changes everything for a patient and their loved *** a brain tumor usually begins with magnetic resonance imaging(MRI).The manual brain tumor diagnosis from the MRO images always requires an expert ***,this process is time-consuming and ***,a computerized technique is required for brain tumor detection in MRI *** the MRI,a novel mechanism of the three-dimensional(3D)Kronecker convolution feature pyramid(KCFP)is used to segment brain tumors,resolving the pixel loss and weak processing of multi-scale lesions.A single dilation rate was replaced with the 3D Kronecker convolution,while local feature learning was performed using the 3D Feature Selection(3DFSC).A 3D KCFP was added at the end of 3DFSC to resolve weak processing of multi-scale lesions,yielding efficient segmentation of brain tumors of different sizes.A 3D connected component analysis with a global threshold was used as a post-processing *** standard Multimodal Brain Tumor Segmentation 2020 dataset was used for model *** 3D KCFP model performed exceptionally well compared to other benchmark schemes with a dice similarity coefficient of 0.90,0.80,and 0.84 for the whole tumor,enhancing tumor,and tumor core,***,the proposed model was efficient in brain tumor segmentation,which may facilitate medical practitioners for an appropriate diagnosis for future treatment planning.

关键词： Brain tumor segmentation connect component analysis deep learning kronecker convolution magnetic resonance imaging