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Assessment of the ballistic response of honeycomb sandwich structures subjected to offset and normal impact

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Defence Technology（防务技术） 2023年第10期28卷 56-73页

作者： Nikhil Khaire Gaurav Tiwari Vivek Patel M.A.iqbal Department of Mechanical Engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Mechanical Engineering Visvesvaraya National Institute of TechnologyNagpur440026India School of Mechanical Engineering Dr.Vishwanath Karad MIT World Peace UniversityPune411038India Department of Civil Engineering Indian Institute of Technology RoorkeeRoorkee247667India

In the present study,experimental and numerical investigations were carried out to examine the behavior of sandwich panels with honeycomb *** high velocity impact tests were carried out using a compressed air gun.A sharp conical nosed projectile was impacted normally and with some offset distance(20 mm and 40 mm).The deformation,failure mode and energy dissipation characteristics were obtained for both kinds of ***,the explicit solver was run in Abaqus to create the finite element *** numerically obtained test results were compared with the experimental to check the accuracy of the *** numerical result was further employed to obtain strain energy dissipation in each element by externally running user-defined code in ***,the influence of inscribe circle diameter and cell wall and face sheet thickness on the energy dissipation,deformation and failure mode was *** result found that ballistic resistance and deformation were higher against offset impact compared to the normal impact *** panel impacted at 40 mm offset distance required 3 m/s and 1.9 m/s more velocity than 0 and 20 mm offset ***,increasing the face sheet and wall thickness had a positive impact on the ballistic resistance in terms of a higher ballistic limit and energy ***,inscribe circle diameter had a negative influence on the ballistic ***,the geometrical parameters of the sandwich structure had a significant influence on the energy dissipation in the different deformation *** energy dissipation in plastic work was highest for circumferential direction,regardless of impact condition followed by tangential,radial and axial directions.

关键词： Honeycomb sandwich structure Offset impact Energy dissipation characteristic Deformation and failure mode Geometry effect

Multi-layer spectral clustering approach to intentional islanding in bulk power systems

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Journal of Modern Power Systems and Clean Energy 2019年第5期7卷 1044-1055页

作者： Faycal ZNIDI Hamzeh DAVARIKIA Kamran iqbal Masoud BARATI Department of Systems Engineering University of Arkansas at Little RockLittle RockARUSA Department of Electrical and Computer Engineering Louisiana State UniversityBaton RougeLAUSA Department of Electrical and Computer Engineering University of PittsburghPittsburghPAUSA

Intentional controlled islanding(ICI)is a final resort for preventing a cascading failure and catastrophic power system *** paper proposes a controlled islanding algorithm that uses spectral clustering over multilayer graphs to find a suitable islanding *** multi-criteria objective function used in this controlled islanding algorithm involves the correlation coefficients between bus frequency components and minimum active and reactive power flow *** to the previous studies,the algorithm is applied in two *** the first stage,groups of coherent buses are identified with the help of modularity clustering using correlation coefficients between bus frequency *** the second stage,the ICI solution satisfying bus coherency with minimum active and reactive power flow disruptions is determined by grouping all nodes using spectral clustering on the multi-layer *** studies on the IEEE 39-bus test system demonstrate the effectiveness of the method in determining an islanding solution in real time while addressing the generator coherency problem.

关键词： Constrained spectral clustering Controlled islanding Bus coherency Multi-layer graph Normalized spectral clustering

Recent advances in multipactor physics and mitigation

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High Voltage 2023年第6期8卷 1095-1114页

作者： Asif iqbal De‐Qi Wen John Verboncoeur Peng Zhang Department of Electrical and Computer Engineering Michigan State UniversityEast LansingMichiganUSA Department of Computational Mathematics Scienceand EngineeringMichigan State UniversityEast LansingMichiganUSA

Recent progress made in the prediction,characterisation,and mitigation of multipactor discharge is reviewed for single‐and two‐surface ***,an overview of basic concepts including secondary electron emission,electron kinetics under the force law,multipactor susceptibility,and saturation mechanisms is provided,followed by a discus-sion on multipactor mitigation *** strategies are categorised into two broad areas–mitigation by engineered devices and engineered radio frequency(rf)*** approach is useful in different *** advances in multipactor physics and engineering during the past decade,such as novel multipactor prediction methods,un-derstanding space charge effects,schemes for controlling multipacting particle trajec-tories,frequency domain analysis,high frequency effects,and impact on rf signal quality are *** addition to vacuum electron multipaction,multipactor‐induced ioni-zation breakdown is also reviewed,and the recent advances are summarised.

关键词： multip kinetics susceptibility

Laboratory to field scale assessment for EOR applicability in tight oil reservoirs

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Petroleum Science 2022年第5期19卷 2131-2149页

作者： Fahad iqbal Syed Amirmasoud Kalantari Dahaghi Temoor Muther Center for Net Carbon Zero GeoEnergy Intelligence and Sustainability(C0GEiS) USA The University of Kansas School of EngineeringChemical and Petroleum Engineering1450 Jayhawk Blvd.LawrenceKS66045USA

Tight oil reservoirs are contributing a major role to fulfill the overall crude oil needs,especially in the ***,the dilemma is their ultra-tight permeability and an uneconomically short-lived primary recovery ***,the application of EOR in the early reservoir development phase is considered effective for fast-paced and economical tight oil *** achieve these objectives,it is imperative to determine the optimum EOR potential and the best-suited EOR application for every individual tight oil reservoir to maximize its ultimate recovery *** most of the tight oil reservoirs are found in wide spatial source rock with complex and compacted pores and poor geophysical properties yet they hold high saturation of good quality oil and therefore,every single percent increase in oil recovery from such huge reservoirs potentially provide an additional million barrels of ***,the EOR application in such reservoirs is quite ***,the physical understanding of EOR applications in different circumstances from laboratory to field scale is the key to success and similarly,the fundamental physical concepts of fluid flow-dynamics under confinement conditions play an important *** paper presents a detailed discussion on laboratory-based experimental achievements at micro-scale including fundamental concepts under confinement environment,physics-based numerical studies,and recent actual field piloting experiences based on the *** *** objective of this paper is to discuss all the critical reservoir rock and fluid properties and their contribution to reservoir development through massive multi-staged hydraulic fracture networks and the EOR *** the CO_(2)and produced hydrocarbon gas injection through single well-based huff-n-puff operational constraints are discussed in detail both at micro and macro scale.

关键词： UEOR UEOR pilots Shale oil Tight oil reservoir Gas injection Hydraulic fracture Huff-n-puff

Fractional synergetic tracking control for robot manipulator

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Journal of Control and Decision 2024年第1期11卷 139-152页

作者： asma Saif Raouf Fareh Saif Sinan Maamar Bettayeb Department of Electrical Engineering University of SharjahSharjahUAE Department of Electrical Engineering École de technologie supérieureMontrealCanada CEIES King Abdulaziz UniversityJeddahSaudi Arabia

This work takes advantage of synergetic control theory and fractional calculus to develop and propose fractional synergetic control(FSC)strategy for Four Degrees of Freedom(4-DOF)robot *** proposed fractional synergetic control is designed to track a joint space as well as workspace desired *** calculus gives more flexibility in the design since it has a wider stability *** to that,as stated in the literature,compared to a similar approach such as sliding mode control,the synergetic control approach converges faster to the equilibrium point,without chattering with a fast *** paper proposes a new control strategy that takes advantage of fractional calculus and synergetic control *** proposed control strategy is tested experimentally on a 4-DOF manipulator to study the performance of the proposed control *** stability of the closed-loop system is proved using the Lyapunov *** experimental results have shown that the proposed FSC design has achieved a good tracking performance.

关键词： Synergetic control robust control robot manipulator fractional controller

Evaluation of Protein Extraction Methods for Vitis vinifera Leaf and Root Proteome Analysis by Two-Dimensional Electrophoresis

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Journal of Integrative Plant Biology 2010年第10期52卷 933-940页

作者： Neila Jellouli asma Ben Salem Abdelwahed Ghorbel Hatem Ben Jouira Laboratoire de Physiologie Moléculaire de la Vigne Centre de Biotechnologie de Borj Cédria

An efficient protein extraction method is crucial to ensure successful separation by two-dimensional electrophoresis （2-DE） for recalcitrant plant species, in particular for grapevine （Vitis vinifera L.）. Trichloroacetic acid-acetone （TCA-acetone） and phenol extraction methods were evaluated for proteome analysis of leaves and roots from the Tunisian cultivar ＇Razegui＇. The phenol-based protocol proved to give a higher protein yield, a greater spot resolution, and a minimal streaking on 2-DE gels for both leaf and root tissues compared with the TCA-based protocol. Furthermore, the highest numbers of detected proteins on 2-DE gels were observed using the phenol extraction from leaves and roots as compared with TCA-acetone extraction.

关键词： PLANT proteins VITIS vinifera LEAVES ROOTS (Botany) PLANT extracts ELECTROPHORESIS SEPARATION (Technology) PHENOLS EXTRACTION (Chemistry) GRAPES PLANT proteomics

Effects of Rapid Urbanization on Vegetation Cover in Major Cities of Pakistan using MODIS Data during 2001-2019

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Effects of Rapid Urbanization on Vegetation Cover in Major C...

作者： asma Amir 东北师范大学

学位级别：硕士

植被是陆地生态系统最重要的组成部分之一。它是地球上生命的重要组成部分,因为它吸收了大气中的有害气体,对人类和环境都有好处。根据一些研究和人口普查,世界各地的人口数量增长迅速。人口的增加正在对世界各地的植被造成巨大影响。... 详细信息

植被是陆地生态系统最重要的组成部分之一。它是地球上生命的重要组成部分,因为它吸收了大气中的有害气体,对人类和环境都有好处。根据一些研究和人口普查,世界各地的人口数量增长迅速。人口的增加正在对世界各地的植被造成巨大影响。巴基斯坦是植被覆盖受到严重影响的国家之一,因为人口不断增加,特别是在城市地区。本研究的主要目的是分析快速城市化对巴基斯坦主要城市植被覆盖的影响。植被覆盖率从MODIS植被指数月积(MOD13A3)数据中提取。利用MODIS衍生的土地覆盖类型产品(MCD12Q1)数据计算了2001年至2019年的城市面积变化。通过在城市地区周围产生25公里的缓冲区,从MODIS衍生的城市和建筑用地计算出农村地区。EVI(ΔEVI)的变化是根据城市EVI和农村EVI之间的差异来计算的。夜间光照时间序列数据被广泛用于提取城市化区域,因此本研究也将其用于验证MODIS数据的结果。据观察,从2001年到2019年,整个巴基斯坦的城市和建筑用地显著增加,约965 km,增加趋势约为50km/年。2001-2010年间,巴基斯坦城市和建设用地面积增加了27.04 km,2011-2019年增加到89.12 km。结果表明,拉合尔的城区面积增加约32 km,使其成为城市和建成区土地利用变化最大的城市。相反,海得拉巴成为研究期内城市和建成区土地利用变化最小的城市。本研究计算了2001年至2019年巴基斯坦EVI的总体平均值。2001年至2019年,EVI的总体平均值呈增长趋势,增加了约0.06,增长速率约为0.0027/年,但趋势不显著。2001年至2019年,伊斯兰堡市的平均EVI增幅最大,为0.0949;而木尔坦市的平均EVI增幅最小,为0.0287。研究期内,巴基斯坦的大部分城市的ΔEVI均呈显著下降趋势(p<0.01)。采用Pearson相关分析方法,研究了城市建设用地变化与ΔEVI的关系。城市用地和建成区用地与ΔEVI呈显著负相关(p<0.01)。因此,城区扩张和建筑用地面积增加对植被生长造成了负面影响。利用DMSP/OLS夜间灯光时间序列数据对MODIS数据的计算结果进行了验证。从夜间灯光数据中提取的城区面积变化与ΔEVI同样呈显著负相关(p<0.01)。

关键词：植被城市化 MODIS EVI 夜间灯光

Heterogeneous Expansion of End-moraine Dammed Lakes in the Hindukush-Karakoram-Himalaya Ranges of Pakistan during 2001-2013

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Journal of Mountain Science 2015年第5期12卷 1113-1124页

作者： Arshad ASHRAF Rozina NAZ Muhammad Bilal iqbal Climate Change Alternate Energy and Water Resources Institute (CAEWRI) National Agricultural Research Center

Global climate change during the twentieth century had a significant impact on the glaciers that resulted in creation of new lakes and expansion of existing ones, and ultimately an increase in the number of glacial lake outburst floods(GLOFs) in the Himalayan region. This study reports variation of the end-moraine dammed lakes in the high altitude Hindukush-Karakoram-Himalaya(HKH) region of Pakistan to evaluate future floods hazard under changing climate in this region. An integrated temporal remote sensing and Geographic information system(GIS) based approach using satellite images of Landsat-7 and 8 was adopted to detect 482 endmoraine dammed lakes out of which 339 lakes(>0.02 km2) were selected for temporal change analysis during the 2001-2013 period. The findings of the study revealed a net expansion in the end-moraine dammed lakes area in the Karakoram(about 7.7%) and in the Himalayas(4.6%), while there was a net shrinkage of about 1.5% in the lakes area in the Hindukush range during this period. The percentage increase in the lakes' area was highest above 4500 m asl in the Hindukush, within 3500-4000 m asl in the Himalayas and below 3500 m asl in the Karakoram range. The overall positive change in the lakes' area appears to prevail in various altitudinal ranges of the region. The heterogeneous areal changes in the endmoraine dammed lakes might be attributed to different climate regimes and glacial hydrodynamics in the three HKH ranges. A periodic monitoring of the glacial lakes and their associated glaciers is essential for developing effective hazard assessment and risk reduction strategies for this high altitude Himalayan region.

关键词： End-moraine glacial lakes GLOF Karakoram Himalayan region

Estimates and burden of foodborne pathogens in RTE beverages in relation to vending practices

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Food Quality and Safety 2019年第2期3卷 107-115页

作者： asma Afreen Zaheer Ahmed Hajra Ahmad Nauman Khalid Department of Home and Health Sciences Research ComplexAllama Iqbal Open UniversityIslamabadPakistan School of Food and Agricultural Sciences University of Management and TechnologyLahorePakistan

Objectives:Growing trend of street-vended food in underdeveloped countries offers low-cost food to many sections of *** it provides job opportunities to many urban dwellers,several health hazards are associated with this *** present study investigates the burden of foodborne pathogens in Ready-To-Eat(RTE)beverages in relation to vending practices among street vendors of Rawalpindi City,Pakistan according to standardized methods and *** and Methods:Six densely populated locations of Rawalpindi city were *** consumed sugar cane juice(SCJ)and tamarind prune(dried plums)drink(TPD)(locally called as Imli Alu Bukhara sherbet)from five vendors from each location were chosen in summer season where the temperature reaches above 40℃.Mean and the standard deviation were obtained by univariate and bivariate *** between the study variables was assessed through cross-tabulations,chi-square,and correlation ***:All the samples were found unsatisfactory in comparison to guidelines of aerobic plate *** coliform was observed in 86.7 per cent of SCJ and 70.0 per cent of TPD *** samples of SCJ exceeded the limit of>1100 MPN/ml value,whereas samples of TPD exceeded this limit for Escherichia *** of SCJ and 93.3 per cent of TPD samples depicted the presence of Salmonella *** *** found significantly high in 73.3 per cent samples of SCJ and 23.3 per cent samples of ***:The incidence of high bioloads attributes towards a potential reservoir of foodborne pathogens due to unhygienic vending practices.

关键词： Ready-To-Eat beverages foodborne pathogens street vendors vending practices