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International Journal of Minerals,Metallurgy and Materials 2013年第10期20卷 953-960页

作者： Amir Momeni shahab Kazemi Ali Bahrani Materials Science and Engineering Department Hamedan University of Technology Department of Materials Engineering Faculty of EngineeringBu Ali Sina University

The hot deformation characteristics of 1.4462 duplex stainless steel （DSS） were analyzed by considering strain partitioning between austenite and ferrite constituents. The individual behavior of ferrite and austenite in microstructure was studied in an iso-stress condition. Hot compression tests were performed at temperatures of 800-1100~C and strain rates of 0.001-1 s-1. The flow stress was modeled by a hyperbolic sine constitutive equation, the corresponding constants and apparent activation energies were determined for the studied alloys. The constitutive equation and law of mixture were used to measure the contribution factor of each phase at any given strain. It is found that the contribution factor of ferrite exponentially declines as the Zener-HoUomon parameter （Z） increases. On the contrary, the austenite contribution polynomially increases with the increase of Z. At low Z values below 2.6. x 1015 （lnZ---35.5）, a negative contribution factor is determined for austenite that is attributed to dynamic recrystallization. At high Z values, the contribution factor of austenite is about two orders of magnitude greater than that of ferrite, and therefore, austenite can accommodate more strain. Microstructural characterization via electron back-scattered diffraction （EBSD） confirms the mechanical results and shows that austenite recrystallization is possible only at high temperature and low strain rate.

关键词： duplex stainless steel compression testing strain partitioning high temperature operations deformation

A hybrid deterministic-stochastic model for spouted beds

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Particuology 2019年第1期17卷 104-113页

作者： shahab Golshan Reza Zarghami Navid Mostoufi Process Design and Simulation Research Centre. School of Chemical Engineering. College of Engineering University of Tehran. TehranIran

A new hybrid deterministic-stochastic model is developed and used to simulate a slot-rectangular spouted *** model includes deterministic and stochastic steps that are executed in *** simulation starts with the deterministic part of the model,in which the computational fluid dynamics-discrete element method (CFD-DEM) equations are solved for 1 s to give the initial velocity distribution of the *** stochastic part is then executed,with the hydrodynamics of the bed taken from the velocity distributions acquired in the first step through Monte Carlo sampling.A full deterministic (CFD-DEM) simulation of the bed is also conducted for comparison with the proposed hybrid ***,the proposed hybrid is validated using experimental data from the *** validations are based on the axial and lateral velocity distributions of the particles and the bed *** effects of the cell size and number of sampling steps on the accuracy of the model are also *** performance of the proposed model is compared with the CFD-DEM results in terms of the computation time and the rate of solid circulation in the *** hybrid model is found to have shorter runtimes than the CFD-DEM approach.

关键词： CFD–DEM Monte Carlo Spouted bed Hydrodynamics Solid circulation rate

Simulation of Vortex-Induced Vibrations of A Cylinder Using ANSYS CFX Rigid Body Solver

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China Ocean Engineering 2017年第1期31卷 79-90页

作者： IZHAR Abubakar QURESHI Arshad Hussain KHUSHNOOD shahab University of Engineering and Technology Lahore Pakistan University of Engineering and Technology Taxila Pakistan

This article simulates the vortex-induced oscillations of a rigid circular cylinder with elastic support using the new ANSYS CFX rigid body solver. This solver requires no solid mesh to setup FSI（Fluid Structure Interaction）simulation. The two-way case was setup in CFX only. Specific mass of the cylinder and flow conditions were similar to previous experimental data with mass damping parameter equal to 0.04, specific mass of 1 and Reynolds number of 3800. Two dimensional simulations were setup. Both one-degree-of-freedom and two-degree-of-freedom cases were run and results were obtained for both cases with reasonable accuracy as compared with experimental ***-figure XY trajectory and lock-in behavior were clearly captured. The obtained results were satisfactory.

关键词： cylinder solver Reynolds vortex freedom Vortex circular satisfactory figure captured

Full field reservoir modeling of shale assets using advanced data-driven analytics

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Geoscience Frontiers 2016年第1期7卷 11-20页

作者： Soodabeh Esmaili shahab D.Mohaghegh Asset Development Team North OperationCalifornia Resources CorporationCalifornia 90024USA West Virginia University 345-E Mineral Resources Bldg.P.O.Box 6070MorgantownWV 26506USA

Hydrocarbon production from shale has attracted much attention in the recent years. When applied to this prolific and hydrocarbon rich resource plays, our understanding of the complexities of the flow mechanism（sorption process and flow behavior in complex fracture systems- induced or natural） leaves much to be desired. In this paper, we present and discuss a novel approach to modeling, history matching of hydrocarbon production from a Marcellus shale asset in southwestern Pennsylvania using advanced data mining, pattern recognition and machine learning technologies. In this new approach instead of imposing our understanding of the flow mechanism, the impact of multi-stage hydraulic fractures, and the production process on the reservoir model, we allow the production history, well log, completion and hydraulic fracturing data to guide our model and determine its behavior. The uniqueness of this technology is that it incorporates the so-called ＂hard data＂ directly into the reservoir model, so that the model can be used to optimize the hydraulic fracture process. The ＂hard data＂ refers to field measurements during the hydraulic fracturing process such as fluid and proppant type and amount, injection pressure and rate as well as proppant concentration. This novel approach contrasts with the current industry focus on the use of ＂soft data＂（non-measured, interpretive data such as frac length, width,height and conductivity） in the reservoir models. The study focuses on a Marcellus shale asset that includes 135 wells with multiple pads, different landing targets, well length and reservoir properties. The full field history matching process was successfully completed using this data driven approach thus capturing the production behavior with acceptable accuracy for individual wells and for the entire asset.

关键词： Reservoir modeling Data driven reservoir modeling Top-down modeling Shale reservoir Modeling Shale

Simulation of Vortex-Induced Vibrations of A Cylinder Using ANSYS CFX

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China Ocean Engineering 2014年第4期28卷 541-556页

作者： Abu Bakar IZHAR Arshad Hussain QURESHI shahab KHUSHNOOD University of Engineering & Technology Lahore Pakistan University of Engineering & Technology Taxila Pakistan

In this paper, vortex-induced vibrations of a cylinder are simulated by use of ANSYS CFX simulation code. The cylinder is treated as a rigid body and transverse displacements are obtained by use of a one degree of freedom spring damper system. 2-D as well as 3-D analysis is performed using air as the fluid. Reynolds number is varied from 40 to 16000 approx., covering the laminar and turbulent regimes of flow. The experimental results of （Khalak and Williamson, 1997） and other researchers are used for validation purposes. The results obtained are comparable.

关键词： vortex-induced vibrations ANSYS CFX flow induced vibrations fluid structure interaction

Dynamic recrystallization and precipitation in high manganese austenitic stainless steel during hot compression

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International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 36-45页

作者： Amir Momeni shahab Kazemi Golam Ebrahimi Alireza Maldar Materials Science and Engineering Department Hamedan University of Technology Department of Materials Engineering Faculty of EngineeringBu Ali Sina University Department of Materials and Polymer Engineering Hakim Sabzevari University

Dynamic recrystallization and precipitation in a high manganese austenitic stainless steel were investigated by hot compression tests over temperatures of 950-1150~C at strain rates of 0.001 s-1-1 s-1. All the flow curves within the studied deformation regimes were typ- ical of dynamic recrystallization. A window was constructed to determine the value of apparent activation energy as a function of strain rate and deformation temperature. The kinetics of dynamic recrystallization was analyzed using the Avrami kinetics equation. A range of apparent activation energy for hot deformation from 303 kJ/mol to 477 kJ/mol is obtained at different deformation regimes. Microscopic characterization confirms that under a certain deformation condition （medium Zener-Hollomon parameter （Z） values）, dynamic recrystalliza- tion appears at first, but large particles can not inhibit the recrystallization. At low or high Z values, dynamic recrystallization may occur be- fore dynamic precipitation and proceeds faster. In both cases, secondary phase precipitation is observed along prior austenite grain bounda- ries. Stress relaxation tests at the same deformation temperatures also confirm the possibility of dynamic precipitation. Unexpectedly, the Avrami＇s exponent value increases with the increase of Z value. It is associated with the priority of dynamic recrystallization to dynamic precipitation at higher Z values.

关键词： austenitic stainless steel hot deformation dynamic recrystallization precipitation activation energy

Functional gastrointestinal disorders and gut-brain axis: What does the future hold?

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World Journal of Gastroenterology 2019年第5期25卷 552-566页

作者： Kashif Mukhtar Hasham Nawaz shahab Abid Centre of Excellence in Women and Child Health Aga Khan University Department of Medicine Section of Gastroenterology Aga Khan University

Despite their high prevalence, lack of understanding of the exact pathophysiology of the functional gastrointestinal disorders has restricted us to symptomatic diagnostic tools and therapies. Complex mechanisms underlying the disturbances in the bidirectional communication between the gastrointestinal tract and the brain have a vital role in the pathogenesis and are key to our understanding of the disease phenomenon. Although we have come a long way in our understanding of these complex disorders with the help of studies on animals especially rodents, there need to be more studies in humans, especially to identify the therapeutic targets. This review study looks at the anatomical features of the gut-brain axis in order to discuss the different factors and underlying molecular mechanisms that may have a role in the pathogenesis of functional gastrointestinal disorders. These molecules and their receptors can be targeted in future for further studies and possible therapeutic interventions. The article also discusses the potential role of artificial intelligence and machine learning and its possible role in our understanding of these scientifically challenging disorders.

关键词： Functional gastrointestinal disorders Idiopathic bowel syndrome Gut-brain axis Microbiome-gut-brain axis Machine learning Artificial intelligence

Subsurface analytics: Contribution of artificial intelligence and machine learning to reservoir engineering, reservoir modeling, and reservoir management

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Petroleum Exploration and Development 2020年第2期47卷 225-228页

作者： MOHAGHEGH shahab D. Petroleum&Natural Gas Engineering West Virginia UniversityMorgantownWV 26506USA

Traditional Numerical Reservoir Simulation has been contributing to the oil and gas industry for *** current state of this technology is the result of decades of research and development by a large number of engineers and *** in the late 1960s and early 1970s,advances in computer hardware along with development and adaptation of clever algorithms resulted in a paradigm shift in reservoir studies moving them from simplified analogs and analytical solution methods to more mathematically robust computational and numerical solution models.

关键词： and reservoir management Contribution of artificial intelligence and machine learning to reservoir engineering Subsurface analytics reservoir modeling

A computational fluid dynamics investigation of a novel flooded-bed dust scrubber with vibrating mesh

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International Journal of Mining Science and Technology 2022年第3期32卷 525-537页

作者： Zhaokuan Lu Aishwarya Rath Seyed Hassan Amini Aaron Noble Shima shahab Department of Mechanical Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA Department of Mining Engineering West Virginia UniversityMorgantownWV 26506USA Department of Mining and Minerals Engineering Virginia Polytechnic Institute and State UniversityBlacksburgVA 24061USA

This work proposes a vibrating mesh screen as an alternative to the static mesh screen currently used in conventional flooded-bed dust scrubbers for removing airborne coal mine dust in the continuous mining *** assessments suggest that a vibrating screen may improve the dust collection efficiency of scrubber systems and mitigate the clogging issues associated with the conventional *** evaluate this hypothesis,computational fluid dynamics(CFD)simulations were carried out to assess the effects of vibration conditions(i.e.,frequency and amplitude)on the dust particle-mesh interaction and mesh wetting conditions,which are the two decisive factors in determining the dust collection *** results suggest that the vibrating mesh screen can enhance dust particle collision opportunities on the mesh and increase mesh wetted area as compared to the static mesh *** effects of mesh screen aperture,coal dust concentration,and spray nozzle flow rate on the performance of the vibrating mesh are also ***,a simplified three-phase flow simulation including airflow,dust particles,and water droplet spray is performed,and the results reflect a significant improvement of dust collection efficiency in the liquid-coated vibrating mesh screen.

关键词： Dust control Air filtration Flooded-bed scrubber Vibrating mesh filter Continuous miner Computational fluid dynamics Multiphase flow

Alunite processing method selection using the AHP and TOPSIS approaches under fuzzy environment

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International Journal of Mining Science and Technology 2016年第6期26卷 1017-1023页

作者： Alizadeh shahab Salari Rad Mohammad Mehdi Bazzazi Abbas Aghajani Mining Engineering Department Amirkabir University of Technology Tehran *** Iran Mining Engineering Department University of Kashan Kashan *** Iran

Alunite is the most important non bauxite resource for alumina. Various methods have been proposed and patented for processing alunite, but none has been performed at industrial scale and no technical,operational and economic data is available to evaluate methods. In addition, selecting the right approach for alunite beneficiation, requires introducing a wide range of criteria and careful analysis of *** this research, after studying the existing processes, 13 methods were considered and evaluated by 14 technical, economic and environmental analyzing criteria. Due to multiplicity of processing methods and attributes, in this paper, Multi Attribute Decision Making methods were employed to examine the appropriateness of choices. The Delphi Analytical Hierarchy Process(DAHP) was used for weighting selection criteria and Fuzzy TOPSIS approach was used to determine the most profitable candidates. Among 13 studied methods, Spanish, Svoronos and Hazan methods were respectively recognized to be the best choices.

关键词： Alunite Mineral processing methods Multi Attribute Decision Making Delphi Analytical Hierarchy Process (DAHP)Fuzzy TOPSIS