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Communications in Theoretical Physics 2018年第1期69卷 68-76页

作者： Z.Iqbal ehtsham azhar Zaffar Mehmood E.N.Maraj Department of Mathematics Faculty of Sciences HITEC University

Boundary layer stagnation point flow of Casson fluid over a Riga plate of variable thickness is investigated in present article. Riga plate is an electromagnetic actuator consists of enduring magnets and gyrated aligned array of alternating electrodes mounted on a plane surface. Physical problem is modeled and simplified under appropriate transformations. Effects of thermal radiation and viscous dissipation are incorporated. These differential equations are solved by Keller Box Scheme using MATLAB. Comparison is given with shooting techniques along with RangeKutta Fehlberg method of order 5. Graphical and tabulated analysis is drawn. The results reveal that Eckert number,radiation and fluid parameters enhance temperature whereas they contribute in lowering rate of heat transfer. The numerical outcomes of present analysis depicts that Keller Box Method is capable and consistent to solve proposed nonlinear problem with high accuracy.

关键词： Riga-plate Keller Box method Casson fluid variable thickness stagnation point flow internal heat generation

A Numerical Investigation of Nanocomposite of Copper and Titanium Dioxide in Water Based Fluid Influenced by Instigated Magnetic Region

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Communications in Theoretical Physics 2018年第8期69卷 239-248页

作者： Z.Iqbal ehtsham azhar E.N.Maraj Zaffar Mehmood Department of Mathematics Faculty of Sciences HITEC University

Presence of external electrical field plays a vital role in heat transfer and fluid flow phenomena. Keeping this in view present article is a numerical investigation of stagnation point flow of water based nanoparticles suspended fluid under the influence of induced magnetic field. A detailed comparative analysis has been performed by considering Copper and Titanium dioxide nanoparticles. Utilization of similarity analysis leads to a simplified system of coupled nonlinear differential equations, which has been tackled numerically by means of shooting technique followed by Runge-Kutta of order 5. The solutions are computed correct up to 6 decimal places. Influence of pertinent parameters is examined for fluid flow, induced magnetic field, and temperature profile. One of the key findings includes that magnetic parameter plays a vital role in directing fluid flow and lowering temperature profile. Moreover, it is concluded that Cu-water based nanofluid high thermal conductivity contributes in enhancing heat transfer efficiently.

关键词： water based fluid instigated magnetic region nanoscale particles Copper and titanium dioxide stagnation point flow numerical solutions

黏弹性Jeffery-Hamel流的磁-微结构分析

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Journal of Central South University 2023年第6期30卷 1763-1775页

作者： ehtsham azhar Abid KAMRAN Department of Mathematics and Statistics PMAS Arid Agriculture UniversityRawalpindi 44000Pakistan Department of Mathematics Capital University of Science and TechnologyIslamabad 46000Pakistan

本文通过拉伸/收缩具有独立移动能力大分子的非平行通道,对磁流体的动力学进行数值分析。通过麦克斯韦方法建立了外磁场对黏弹性流体流动影响的数学模型,在经典流体动力动量方程中表现为体力。为了完整描述微观结构现象,利用角动量方程... 详细信息

本文通过拉伸/收缩具有独立移动能力大分子的非平行通道,对磁流体的动力学进行数值分析。通过麦克斯韦方法建立了外磁场对黏弹性流体流动影响的数学模型,在经典流体动力动量方程中表现为体力。为了完整描述微观结构现象,利用角动量方程对数学模型进行强化。用凯勒盒有限差分法对所得到的非线性问题进行数值处理。求解如Hartmann数(1≤Ha≤5)、拉伸参数(-4≤C≤4)、旋转参数(3≤K≤9)、Weissenberg数(0.3≤Wi≤0.9)、Reynolds数(50≤Re≤150)等物理量的微分方程形式,并以图表形式表示出来。在所有讨论的情况中,只有发散通道中的角速度随着Hartmann数的增加而增加,这表明微结构旋转是由强磁场激发的。

关键词： Jeffery-Hamel流黏弹性流体微观结构数值解非线性偏微分方程

Satellite precipitation product:Applicability and accuracy evaluation in diverse region

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Science China(Technological Sciences) 2020年第5期63卷 819-828页

作者： MUHAMMAD ehtsham MUHAMMAD Waseem AHMAD Ijaz MUHAMMAD KHAN Noor CHEN Si Centre of Excellence in Water Resources Engineering University of Engineering and TechnologyLahore 54890Pakistan Department of Civil Engineering University of Engineering and TechnologyLahore 54890Pakistan School of Resources and Environment Hubei UniversityWuhan 430062China Hubei Key Laboratory of Regional Development and Environmental Response Wuhan 430062China

Satellite precipitation products,e.g.,Tropical Rainfall Measuring Mission version-07(hereafter TRMM)and its successor Integrated Multi-Satellite Retrievals for Global Precipitation Measurement(hereafter IMERG)are being used at a global scale for rainfall ***,SM2RAIN-ASCAT(hereafter SM2RAIN)is a novel addition to satellite-based precipitation products which gives the rainfall estimates from the knowledge of soil moisture state and is based on‘bottom to top’approach.A comparative assessment of any newly developed product or a new version of the product is quite vital for algorithm developers and ***,this research work was carried out to evaluate the accuracy and applicability of SM2RAIN,in comparison to in-situ data,TRMM,and IMERG in diverse regions of *** comparative analysis was performed on a temporal scale(daily and monthly)and seasonal scale(spring,autumn,summer,and winter)using five performance metrics namely,root mean square error(RMSE),correlation coefficient(CC),false alarm ratio(FAR),the probability of detection(POD),and critical success index(CSI).The results showed that:(1)SM2RAIN is a better rainfall estimation product in the dry region(having ***>0.35),however,less effective in hilly and mountainous terrain having high rainfall intensity;(2)SM2RAIN provides more satisfactory estimates in winter and autumn seasons,while relative poor in the summer season;(3)SM2RAIN performs better in terms of rainfall detection with an average POD of 0.61;(4)the overall performance of SM2RAIN is very convincing and it was concluded that SM2RAIN can be a feasible satellite product for most of the areas of *** is noteworthy here to mention that this could be the preliminary assessment of SM2RAIN in diverse climatic zones of Pakistan.

关键词： SM2RAIN satellite product TRMM,IMERG Pakistan

Left bundle branch pacing vs biventricular pacing in heart failure patients with left bundle branch block:A systematic review and meta-analysis

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World Journal of Cardiology 2024年第1期16卷 40-48页

作者： Farah Yasmin Abdul Moeed Rohan Kumar Ochani Hamna Raheel Malik Ali ehtsham Awan Ayesha Liaquat Arisha Saleem Muhammad Aamir Nael Hawwa Salim Surani Department of Internal Medicine Yale University School of MedicineNew HavenCT 06511United States Department of Medicine Dow University of Health ScienceKarachi 74200SindhPakistan Department of Medicine SUNNY Upstate Medical UniversitySyracuseNY 13210United States Department of Cardiovascular Medicine Lehigh Valley Heart and Vascular InstituteAllentownPA 18105United States Department of Medicine Cleveland ClinicClevelandOH 44195United States Department of Medicine&Pharmacology Texas A&M UniversityCollege StationTX 77843United States

BACKGROUND Left bundle branch pacing(LBBP)is a novel pacing modality of cardiac resynchronization therapy(CRT)that achieves more physiologic native ventricular activation than biventricular pacing(BiVP).AIM To explore the validity of electromechanical resynchronization,clinical and echocardiographic response of *** Systematic review and Meta-analysis were conducted in accordance with the standard guidelines as mentioned in detail in the methodology *** In our analysis,the success rate of LBBP-CRT was determined to be 91.1%.LBBP CRT significantly shortened QRS duration,with significant improvement in echocardiographic parameters,including left ventricular ejection fraction,left ventricular end-diastolic diameter and left ventricular end-systolic diameter in comparison with *** A significant reduction in New York Heart Association class and B-type natriuretic peptide levels was also observed in the LBBP-CRT group vs BiVP-CRT ***,the LBBP-CRT cohort had a reduced pacing threshold at follow-up as compared to BiVP-CRT.

关键词： Left bundle branch pacing Biventricular pacing QRS duration Left ventricular ejection fraction Heart failure

反激式开关电源故障非侵入式AI诊断方法研究

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电子测量与仪器学报 2024年第9期38卷 212-222页

作者：唐圣学谭立强李从宏严金晶 Muhammad ehtsham Akram 赵金泽河北工业大学省部共建电工装备可靠性与智能化国家重点实验室天津300401 南京工业职业技术大学南京210023

将人工智能技术应用到故障诊断领域可以实现电力设备的自动化、智能化诊断,提高诊断精度和效率。以单输入多输出的反激式开关电源为例,针对其因脆弱元件失效而引起的电路工作性能异常的问题,通过分析不同故障模式的信号特性和可分性,提... 详细信息

将人工智能技术应用到故障诊断领域可以实现电力设备的自动化、智能化诊断,提高诊断精度和效率。以单输入多输出的反激式开关电源为例,针对其因脆弱元件失效而引起的电路工作性能异常的问题,通过分析不同故障模式的信号特性和可分性,提出了融合输入电流和输出电压信息的非侵入式开关电源故障诊断方法。构建了由时域特征及频带小波包奇异熵特征组成的融合时频域信息的多维特征矢量,建立了故障特征与故障模式之间的映射关系。进而,提出了基于人工智能技术的深度神经网络(DNN)故障诊断方法,实时监测反激式开关电源的运行状态,并通过数据分析及时识别故障位置,对潜在故障进行预警。实验结果表明,所提出的方法对单故障和多故障模式均具有良好的诊断效果,诊断准确率可达97.9%,并且,在不同工况下,该方法均可表现出较高的诊断准确率和较强的抗干扰性能。

关键词：人工智能反激式开关电源时域特征小波包奇异熵故障诊断 DNN辨识