检索结果-南通市图书馆

International Journal of Digital Earth 2018年第11期11卷 1132-1150页

作者： Samy Ismail Elmahdy Mohamed mostafa Mohameda Civil and Environmental Engineering Department College of Engineering United Arab Emirates UniversityAl-AinUnited Arab Emirates Irrigation and Hydraulics Department Faculty of EngineeringCairo UniversityGizaEgypt

This study presents a modified low-cost approach,which integrates the spectral angle mapper and image difference algorithms in order to enhance classification maps for the purpose of monitoring and analysing land use/land cover change between 2000 and 2015 for the Emirate of *** approach was modified by collecting 320 training samples from QuickBird images with a spatial resolution of 0.6 m,as well as carrying out field observations,followed by the application of a 3×3 Soble filter,sieving classes,majority/minority analysis,and clump classes of the obtained classification *** accuracy assessment showed that the targeted 2000,2005,2010 and 2015 classification maps have 88.1252%,89.0699%,90.1225%and 96.0965%accuracy,*** results showed that the built-up area increased by 233.721 km^(2)(5.81%)between 2000 and 2005 and continues to increase even up and till the present *** assessment of changes in the periods 2000–2005 and 2010–2015 confirmed that net vegetation area losses were more pronounced from 2000 to 2005 than from 2010 to 2015,dropping from 47,618 to 40,820 km^(2),*** study is aimed to assist urban planners and decision-makers,as well as research institutes.

关键词： Dubai change detection image difference SAM algorithm

The impact of connate water saturation and salinity on oil recovery and CO2 storage capacity during carbonated water injection in carbonate rock

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第7期27卷 1699-1707页

作者： Mahmood Shakiba Masoud Riazi Shahab Ayatollahi mostafa Takband Department of Petroleum Engineering Amirkabir University of TechnologyTehranIran Enhanced Oil Recovery (EOR) Research Centre IOR/EOR Research InstituteShiraz UniversityShirazIran Petroleum Engineering Department School of Chemical and Petroleum Eng.Shiraz UniversityShirazIran School of Chemical and Petroleum Engineering Sharif University of TechnologyTehranIran

Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil *** mechanism is considered as a reason for *** fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding ***,instability at the interface due to disturbances in porous medium promotes viscous fingering *** water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery ***,higher in-situ water content can worsen this ***,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR *** the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil *** this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil *** results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively.

关键词： Carbonated water Connate water Carbonate reservoir Enhanced oil recovery Secondary recovery CO2 storage

A Robust Tracking Controller for Electrically Driven Robot Manipulators: Stability Analysis and Experiment

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2015年第1期12卷 83-92页

作者： Mohamadreza Homayounzade Mehdi Keshmiri mostafa Ghobadi Department of Mechanical Engineering Isfahan University of Technology (IUT) Department of Mechanical Engineering University at Buffalo SUNY

In this paper, a robust controller for electrically driven robotic systems is developed. The controller is designed in a backstepping manner. The main features of the controller are: 1) Control strategy is developed at the voltage level and can deal with both mechanical and electrical uncertainties. 2) The proposed control law removes the restriction of previous robust methods on the upper bound of system uncertainties. 3) It also benefits from global asymptotic stability in the Lyapunov sense. It is worth to mention that the proposed controller can be utilized for constrained and nonconstrained robotic systems. The effectiveness of the proposed controller is verified by simulations for a two link robot manipulator and a four-bar linkage. In addition to simulation results,experimental results on a two link serial manipulator are included to demonstrate the performance of the proposed controller in tracking a given trajectory.

关键词： Electrically driven robots Lyapunov stability parametric uncertainty robust control uncertain actuator dynamics

Semi-hot Stamping as an Improved Process of Hot Stamping

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第4期27卷 369-376页

作者： Malek Naderi mostafa Ketabchi Mahmoud Abbasi Wolfgang Bleck Department of Mining and Metallurgy Amirkabir University of Technology Department of Ferrous Metallurgy RWTH-Aachen University

Reducing the forming load, deletion of springback, increasing the formability of sheets as well as producing high strength parts are the main reasons to apply hot stamping process. Hot stamping process and 22MnB5 steels are the state of the art process and grades, respectively; however novel processes and steel grades are under considerations. In the current research, behavior of the steel grade MSW1200 blanks under semi and fully hot stamping processes was characterized. During semi-hot stamping process, the blank was firstly heated to a temperature of about 650℃ and then formed and quenched in the die assembly, simultaneously. Microstructure and mechanical properties of semi and fully hot stamped blanks were studied and the results were compared with those of normally water/air quenched blanks. The hot stamped blanks attained the strength values as high as water quenched blanks. The highest ductility and consequently, the best formability were achieved for the blank which had been semi-hot stamped. It was concluded that for the mentioned steel, semi-hot stamping process could be considered as an improved thermo-mechanical process which not only guaranteed a high formability, but also led to ultra high strength values.

关键词： Semi-hot stamping Hot stamping MSW1200 steel Mechanical properties

Sound preferences of the dense urban environment： Soundscape of Cairo

在线全文

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2014年第1期3卷 55-68页

作者： mostafa Refat Ismail Department of Architecture Engineering Ain Shams University Cairo 11566 Egypt

A questionnaire study was conducted to investigate the soundscape preferences of the sonic environment in Cairo. Participants, who were Cairo residents, were questioned about their appraisal of fami（iar urban soundscapes in a dose- and open-ended format questionnaire. Psycholinguistic data analysis of verbal descriptions expressed by respondents was conducted to identify the re（evance of semantic categories of environmental sounds and quantitative soundscape aspects for the urban sonic environment of Cairo. Resu（ts confirmed a direct retevance of the linguistic semantic auditory judgment and of the outputs of the quantitative dose-ended questions. Cairenes were also found to express their sonic environment （inguisti- cal（y based on physical properties rather than semantic features and values. Analyzing the relative annoyance increase （RAI） of the dose-ended part, overall positive RAI va（ues for all sound categories reveal how sensitive to noise Cairo residents are. Results further showed that at an RAI value of approximately 27%, sound category perception transforms from positive to negative.

关键词： Acoustics Soundscape Sound preference

Sparse rail network robustness analysis:Functional vulnerability levels of accidents resulting from human errors

在线全文

学校读者我要写书评

暂无评论

Journal of Safety Science and Resilience 2021年第3期2卷 111-123页

作者： Navid Khademi mostafa Bababeik Amirhossein Fani School of Civil Engineering College of EngineeringUniversity of TehranTehranIran

Transportation network vulnerability analysis has developed increasingly in the last decade with the goal to identify the most critical locations against *** this domain,many of the previous researches have focused on congested urban networks;however,there is still a need to consider regional and interurban sparse rail networks,specifically those networks in developing *** such sparse rail networks,there are limited possibilities to redirect trains if a link is disrupted,there might be less possibility of finding redundant alternative routes,and network failures are usually accompanied by a phenomenon called‘unsatisfied demand.’The study reported in this paper stemmed from research aimed to design precautionary actions for a developing country’s sparse railway *** study framework deemed to find the most vulnerable part of an inter-urban sparse rail network using a network scan approach,which found the consequences of network disruptions.A number of criteria were defined to determine the total cost including unsatisfied demand and additional transportation costs due to *** results showed that how well the process of the vulnerability analysis,considering the features of both supply and demand sides,can be a guide for railway authorities in applying system safety measures.

关键词： Railway accidents Vulnerability analyses Network robustness Sparse transportation networks System resilience Developing countries

Semi-empirical modeling of volumetric efficiency in engines equipped with variable valve timing system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第12期23卷 3132-3142页

作者： mostafa Ghajar Amir Hasan Ka Kaee Behrooz Mashadi Department of Automotive Engineering Iran university of Science and Technology

Volumetric efficiency and air charge estimation is one of the most demanding tasks in control of today's internal combustion ***,using three-way catalytic converter involves strict control of the air/fuel ratio around the stoichiometric point and hence requires an accurate model for air charge ***,high degrees of complexity and nonlinearity of the gas flow in the internal combustion engine make air charge estimation a challenging *** is more obvious in engines with variable valve timing systems in which gas flow is more complex and depends on more functional *** results in models that are either quite empirical(such as look-up tables),not having interpretability and extrapolation capability,or physically based models which are not appropriate for onboard *** these problems,a novel semi-empirical model was proposed in this work which only needed engine speed,load,and valves timings for volumetric efficiency *** accuracy and generalizability of the model is shown by its test on numerical and experimental data from three distinct *** test errors are 0.0316,0.0152 and 0.24 for the three engines,*** the performance and complexity of the model were compared with neural networks as typical black box *** the complexity of the model is less than half of the complexity of neural networks,and its computational cost is approximately 0.12 of that of neural networks and its prediction capability in the considered case studies is usually *** results show the superiority of the proposed model over conventional black box models such as neural networks in terms of accuracy,generalizability and computational cost.

关键词： engine modeling modeling and simulation spark ignition engine volumetric efficiency variable valve timing

An Adjustable Variant of Round Robin Algorithm Based on Clustering Technique

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第3期66卷 3253-3270页

作者： Samih M.mostafa Hirofumi Amano Faculty of Computers and Information South Valley UniversityQena83523Egypt Research Institute for Information Technology Kyushu UniversityFukuoka819-0395Japan

CPU scheduling is the basic task within any time-shared operating *** of the main goals of the researchers interested in CPU scheduling is minimizing time *** between CPU scheduling algorithms is subject to some scheduling criteria(e.g.,turnaround time,waiting time and number of context switches(NCS)).Scheduling policy is divided into preemptive and *** Robin(RR)algorithm is the most common preemptive scheduling algorithm used in the time-shared operating *** this paper,the authors proposed a modified version of the RR algorithm,called dynamic time slice(DTS),to combine the advantageous of the low scheduling overhead of the RR and favor short process for the sake of minimizing time *** process has a weight proportional to the weights of all *** process’s weight determines its time slice within the current *** authors benefit from the clustering technique in grouping the processes that are similar in their attributes(e.g.,CPU service time,weight,allowed time slice(ATS),proportional burst time(PBT)and NCS).Each process in a cluster is assigned the average of the processes’time slices in this cluster.A comparative study of six popular scheduling algorithms and the proposed approach on nine groups of processes vary in their attributes was performed and the evaluation was measured in terms of waiting and turnaround times,and *** experiments showed that the proposed algorithm gives better results.

关键词： Clustering CPU scheduling round robin turnaround time waiting time

Ground behaviour analysis,support system design and construction strategies in deep hard rock mining-Justified in Western Australian’s mines

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 1-20页

作者： Behrooz Rahimi mostafa Sharifzadeh Xia-Ting Feng Department of Mining and Metallurgical Engineering Western Australian School of Mines:MineralsEnergy and Chemical Engineering(WASM-MECE)Curtin UniversityKalgoorlieWM6430Australia Key Laboratory of Ministry of Education for Safe Mining of Deep Metal Mines Northeastern UniversityShenyang110819China

Development of deep underground mining projects is crucial for optimum extraction of mineral *** main challenges at great depth are high rock stress levels,seismic events,large-scale deformation,sudden failures and high temperatures that may cause abrupt and unpredictable instability and collapse over a large *** this paper,a ground control and management strategy was presented corresponding to the three stages of projects:strategic design,tactical design and operational *** design is results in preparing a broad plan and primary design for mining *** tactical design is to provide detail design such as stabilisation *** design stage is related to monitoring and updating design *** most effective ground control strategies in this stage are maintenance,rehabilitation,monitoring and contingency ***,a new procedure for design of ground support systems for deep and hard rock was *** main principles are:static and/or dynamic loading types,determination of loading sources,characterisation of geological conditions and the effects of orientation of major structures with openings,estimation of ground loading factor,identification of potential primary and secondary failures,utilisation of appropriate design analysis methods,estimation of depth failure,calculation of the static and/or dynamic demand ground support capacity,and selection of surface and reinforcement *** force is the dominant loading force in low-level *** high stress level failure mechanism becomes more complex in rock mass *** this condition,a variety of factors such as release of stored energy due to seismic events,stress concentration,and major structures influence on ground behaviour and judgement are very *** key rock engineering schemes to minimise the risk of failures in high-stress levels at great depth involve depressurisation and quality control of ***

关键词： Ground management Support system design Sequential excavation Stress management Geotechnical monitoring Deep underground mines

THE EFFECT OF WORKER LEARNING ON SCHEDULING JOBS IN A HYBRID FLOW SHOP： A BI-OBJECTIVE APPROACH

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2018年第3期27卷 265-291页

作者： Farzad Pargar mostafa Zandieh Osmo Kauppila Jaakko Kujala Industrial Engineering and Management Faculty of Technology University ofOulu Oulu Finland Department of Industrial Management Management and Accounting Faculty Shahid Beheshti University G.C.Tehran Iran

This paper studies learning effect as a resource utilization technique that can model improvement in worker＇s ability as a result of repeating similar tasks. By considering learning of workers while performing setup times, a schedule can be determined to place jobs that share similar tools and fixtures next to each other. The purpose of this paper is to schedule a set of jobs in a hybrid flow shop （HFS） environment with learning effect while minimizing two objectives that are in conflict： namely maximum completion time （makespan） and total tardiness. Minimizing makespan is desirable from an internal efficiency viewpoint, but may result in individual jobs being scheduled past their due date, causing customer dissatisfaction and penalty costs. A bi-objective mixed integer programming model is developed, and the complexity of the developed bi-objective model is compared against the bi-criteria one through numerical examples. The effect of worker learning on the structure of assigned jobs to machines and their sequences is analyzed. Two solution methods based on the hybrid water flow like algorithm and non-dominated sorting and ranking concepts are proposed to solve the problem. The quality of the approximated sets of Pareto solutions is evaluated using several performance criteria. The results show that the proposed algorithms with learning effect perform well in reducing setup times and eliminate the need for setups itself through proper scheduling.

关键词： Bi-objective scheduling hybrid flow shop learning effect meta-heuristic