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Journal of Natural Gas Chemistry 2008年第1期17卷 8-16页

作者： Nakisa Yaghobi Mir hamid Reza Ghoreishy Iran Polymer and Petrochemical Institute P.O.Box14965/115TehranIran

The oxidative coupling of methane （OCM） to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separate energy equations for the gas and solid phases coupled with an experimental kinetic model. A lumped kinetic model containing four main species CH4, O2, COx （CO2, CO）, and C2 （C2H4 and C2H6） was used with a plug flow reactor model as well. The results from the model agreed with the experimental data. The model was used to analyze the influence of temperature and feed gas composition on the conversion and selectivity of the reactor performance. The analytical results indicate that the conversion decreases, whereas, C2 selectivity increases by increasing gas hourly space velocity （GHSV） and the methane conversion also decreases by increasing the methane to oxygen ratio.

关键词： oxidative coupling of methane simulation kinetics fixed bed catalytic reactor ethylene

Closed-form dynamics of a hexarot parallel manipulator by means of the principle of virtual work

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Acta Mechanica Sinica 2018年第5期34卷 883-895页

作者： Siamak Pedrammehr Saeid Nahavandi hamid Abdi Institute for Intelligent Systems Research and Innovation Deakin UniversityWaurn Ponds CampusGeelongVIC 3217Australia

In this research,a systematic approach to solving the inverse dynamics of hexarot manipulators is addressed using the methodology of virtual *** the first time,a closed form of the mathematical formulation of the standard dynamic model is presented for this class of *** efficient algorithm for solving this closed-form dynamic model of the mechanism is developed and it is used to simulate the dynamics of the system for different *** of the proposed model is performed using SimMechanics and it is shown that the results of the proposed mathematical model match with the results obtained by the SimMechanics model.

关键词： Parallel mechanism Hexarot Simulator Dynamics Virtual work principle

A comparison between powder flow property testers

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Particuology 2017年第3期15卷 10-20页

作者： hamid Salehi Diego Barletta Massimo Poletto Dipartimento di lngegneria lndustriale Universita degli Studi di Salerno Via Giovanni Paolo II 132 84084 Fisciano SA Italy

In this work, three different shear testers-the Jenike shear cell tester, the Schulze ring shear tester, and the Brookfield powder flow tester-were compared in terms of the raw shear stress time series, yield loci points, angle of internal friction, cohesion, and unconfined yield strength. The three different powders of dolomitic lime, calcium lactate, and calcium carbonate were used for these comparisons. These three powders were characterized into different flowability classes using the ]enike classification, wherein dolomitic lime falls into the cohesive range, calcium lactate falls into the free-flowing range, and calcium carbonate falls into the very cohesive range. Results showed that the best agreement between the testers was found with moderately cohesive powders such as dolomitic lime. Furthermore, the free-flowing material tends to produce more consistent data between the three testers in terms of shear stresses and yield loci. It should be noted that the pre-shear data of free-flowing powder obtained by the Jenike shear cell must be appropriately interpreted. The largest differences between the testers are found with calcium carbonate, which is a highly compressible powder. The ways in which a high powder compressibility can differently affect the results obtained with the different testers were discussed.

关键词： Powder flow property Shear tester Flowability Jenike tester Schulze tester Brookfield powder flow tester

Augmented input estimation in multiple maneuvering target tracking

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Journal of Systems Engineering and Electronics 2019年第5期30卷 841-851页

作者： HADAEGH Mahmoudreza KHALOOzadEH hamid BEHESHTI Mohammadtaghi Department of Electrical and Computer Engineering Science and Research BranchIslamic Azad UniversityTehran ***Iran Department of Systems and Control K.N.Toosi University of TechnologyTehran ***Iran Department of Electrical Engineering Control GroupTarbiat Modares UniversityTehran 14115111Iran

This paper presents augmented input estimation(AIE)for multiple maneuvering target ***-target tracking(MTT)is based on two main parts,data association and *** data association(DA),the best observations are assigned to the considered *** real conditions,the number of observations is more than targets and also locations of observations are often so scattered that the association between targets and observations cannot be done *** this case,for general MTT problems with unknown numbers of targets,we present a Markov chain Monte-Carlo DA(MCMCDA)algorithm that approximates the optimal Bayesian filter with low complexity in *** DA,estimation and tracking should be *** in general cases,many targets can have maneuvering motions,then AIE is proposed to cover both the non-maneuvering and maneuvering parts of motion and the maneuver detection procedure is *** model with an input estimation(IE)approach is a special augmentation in the state space model which considers both the state vector and the unknown input vector as a new augmented state *** comparisons based on the Monte-Carlo simulations are also made to evaluate the performances of the proposed method and other older methods in MTT.

关键词： multi-target tracking (MTT) Markov chain Monte-Carlodata association (MCMCDA) data association (DA) augmentedinput estimation (AIE)

Presentation of a multi-index clustering technique for the mathematical programming of block-cave scheduling

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International Journal of Mining Science and Technology 2018年第6期28卷 941-950页

作者： Farshad Nezhadshahmohammad Yashar Pourrahimian hamid Aghababaei Urmia University Urmia ***Iran School of Mining and Petroleum Engineering University of AlbertaEdmonton T6G 1H9Canada Sahand University of Technology Tabriz 5135/1996Iran

Long-term planning is one of the most important stages that determines the distribution of cash flows over the mine life and the feasibility of the project. However, it is not feasible in block caving to generate a production schedule that will provide optimal operating strategies without considering geotechnical constraints. This paper develops a mixed-integer linear programming(MILP) model to optimize the extraction sequence of drawpoints over multiple time horizons of block-cave mines with respect to the draw control systems. A multi-similarity index clustering technique to solve the MILP model in a reasonable time is also presented. Application and comparison of production scheduling based on the draw control system and clustering technique are illustrated using 325 drawpoints over 15 periods. The results show a significant reduction in the size of the MILP model, and in the time required to solve it.

关键词： Production scheduling Block-cave mining Multi-similarity index clustering Draw control system Production rate curve

How do machine learning techniques help in increasing accuracy of landslide susceptibility maps?

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Geoscience Frontiers 2020年第3期11卷 871-883页

作者： Yacine Achour hamid Reza Pourghasemi Department of Civil Engineering Bordj Bou Arreridj University34030El AnnasserAlgeria Department of Natural Resources and Environmental Engineering College of AgricultureShiraz UniversityShirazIran

Landslides are abundant in mountainous *** are responsible for substantial damages and losses in those *** A1 Highway,which is an important road in Algeria,was sometimes constructed in mountainous and/or semi-mountainous *** studies of landslide susceptibility mapping conducted near this road using statistical and expert methods have yielded ordinary *** this research,we are interested in how do machine learning techniques help in increasing accuracy of landslide susceptibility maps in the vicinity of the A1 Highway *** do this,an important section at Ain Bouziane(NE,Algeria) is chosen as a case study to evaluate the landslide susceptibility using three different machine learning methods,namely,random forest(RF),support vector machine(SVM),and boosted regression tree(BRT).First,an inventory map and nine input factors were prepared for landslide susceptibility mapping(LSM) *** three models were constructed to find the most susceptible areas to this *** results were assessed by calculating the receiver operating characteristic(ROC) curve,the standard error(***),and the confidence interval(CI) at 95%.The RF model reached the highest predictive accuracy(AUC=97.2%) comparatively to the other *** outcomes of this research proved that the obtained machine learning models had the ability to predict future landslide locations in this important road *** addition,their application gives an improvement of the accuracy of LSMs near the road *** machine learning models may become an important prediction tool that will identify landslide alleviation actions.

关键词： Spatial modelling Support vector machine Random forest Boosted regression tree Validation measures Algeria

Seismic analysis of dam-foundation-reservoir system including the effects of foundation mass and radiation damping

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 203-218页

作者： hamid Mohammadnezhad Mohsen Ghaemian Ali Noorzad Department of Civil Engineering Sharif University of Technology Faculty of Civil Water and Environmental Engineering Shahid Beheshti University

One of the main concerns in using commercial software for finite element analyses of dam-foundation-reservoir systems is that the simplifying assumptions of the massless foundation are unreliable. In this study, an appropriate direct finite element method is introduced for simulating the mass, radiation damping and wave propagation effect in foundations of damfoundation-reservoir systems using commercial software ABAQUS. The free-field boundary condition is used for modeling the semi-infinite foundation and radiation damping, which is not a built-in boundary condition in most of the available commercial software for finite element analysis of structures such as ANSYS or ABAQUS and thus needs to be implemented differently. The different mechanism for modeling of the foundation, earthquake input and far-field boundary condition is described. Implementation of the free-field boundary condition in finite element software is verified by comparing it with analytical results. To investigation the feasibility of the proposed method in dam-foundation-reservoir system analysis, a series of analyses is accomplished in a variety of cases and the obtained results are compared with the substructure method by using the EAGD-84 program. Finally, the massed and massless foundation results are compared and it is concluded that the massless foundation approach leads to the overestimation of the displacements and stresses within the dam body.

关键词： dam-foundation interaction radiation damping free-field boundary condition massed foundation

A Comparative Study of the Application of Electronic Data Interchange and Internet Technology to Business Process Reengineering

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Tsinghua Science and Technology 2004年第4期9卷 489-496页

作者： hamid Reza Ahadi School of Economics and Management Tsinghua University Beijing 100084 China

This study investigates the role of information technology in business process reengineering (BPR) implementation. To increase the prospects of successful BPR implementation, the role of information technology in BPR should be thoroughly investigated to find the logical relationships between information technology and BPR. This study used a survey methodology to gather information from 72 BPR programs. The results show that different information technologies, such as those examined in this study, electronic data interchange (EDI) and Internet, provide different capabilities and can be useful in different ways and for different purposes. Lack of attention to these relationships may be due to the unacceptable high implemen-tation failure rate in the previous BPR efforts.

关键词： business process reengineering organizational enablers information technology

The non-isothermal gravimetric method for study the thermal decomposition kinetic of HNBB and HNS explosives

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Defence Technology（防务技术） 2020年第1期16卷 251-256页

作者： hamid Reza Pouretedal Sajjad Damiri Zahra Bighamian Faculty of Applied Chemistry Malek-ashtar University of TechnologyShahin-ShahrIran

The hexanitrostilben(HNS) is a thermally stable explosive that can be prepared from hexanitrobibenzyl(HNBB).Therefore,the investigation of thermal stability of HNBB can be important in the yield of preparation of *** decomposition kinetic of HNBB and HNS are studied by non-isothermal gravimetric *** TG/DTG curves in non-isothermal method are obtained in range of 25℃-400℃at heating rates of 3℃/min,5℃/min,8℃/min,10℃/min and 12℃/*** data of weighttemperature are used for calculation of activation energy(E_a) of thermal decomposition reactions by methods of Ozawa,Kissinger,Ozawa-Flynn-Wall(OFW) and Kissinger-Akahira-Sunose(KAS) as modelfree methods and Strink's equation as model-fitting *** compensation effect is used for prediction of mechanism and determination of pre-exponential factor(InA) of the decomposition reaction.A reduction 60 kj/mol for the average of activation energy of thermal decomposition reaction of HNBB is obtained versus *** result shows the lower thermal stability of HNBB in comparison to HNS,The Avrami equation(A_(3/2)) with function f(α)=3/2(1-α)[-In(1-α)]^(1/3) indicates the predicted mechanism for thermal decomposition reaction both explosives.

关键词： HNS HNBB Decomposition Thermal Kinetic

Fluidized bed coating efficiency and morphology of coatings for producing Al-based nanocomposite hollow spheres

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International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1146-1151页

作者： Mostafa Amirjan hamid Khorsand Manouchehr Khorasani Faculty of Materials Science and Engineering K. N. Toosi University of TechnologyP.O. Box 15875-4416 Tehran Iran Color and Polymer Research Center (CPRC) Amirkabir University of TechnologyP.O. Box 15875-4413 Tehran Iran

Abstract： We performed fluidized bed coating ofAl-based nanoeomposite powder-binder suspensions onto polymer substrates. The effects of the type and amount of the binder and nanoparticle additive on the coating process efficiency and coating characteristics were investigated. The efficiency decreased from 52% to 49% as the processing time increased from 15 to 20 min. However, the amount and thickness of the coating also increased as the processing time and amount of the binder were increased. The addition of nanoparticles to the system decreased the thickness of the coating from 222 to 207 μm when polyvinyl alcohol （PVA） was used as a binder. The suspension containing 3wt% R-4410 binder exhibited the greatest efficiency of 60%.

关键词： fluidized bed coating aluminum nanocomposites efficiency nanoparticles hollow spheres binders