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Separation of methane from different gas mixtures using modified silicon carbide nanosheet: Micro and macro scale numerical studies

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1268-1276页

作者： Golchehreh bayat Roozbeh Saghatchi Jafar Azamat Alireza Khataee Research Laboratory of Advanced Water and Wastewater Treatment Processes Department of Applied ChemistryFaculty of ChemistryUniversity of TabrizTabriz 51666-16471Iran Integrated Manufacturing Technologies Research and Application Center Faculty of Engineering and Natural SciencesSabanci UniversityOrhanliTuzlaIstanbul 34956Turkey Department of Basic Sciences Farhangian UniversityTehranIran Department of Environmental Engineering Gebze Technical UniversityGebze 41400Turkey Institute of Research and Development Duy Tan UniversityDa Nang 550000Viet Nam

This research discusses the separation of methane gas from three different gas mixtures,CH4/H2 S,CH4/N2 and CH4/CO2,using a modified silicon carbide nanosheet(Si CNS)membrane using both molecular dynamics(MD)and computational fluid dynamics(CFD)*** research examines the effects of different structures of the Si CNSs on the separation of these gas *** parameters including the potential of the mean force,separation factor,permeation rate,selectivity and diffusivity are discussed in *** MD simulations showed that the separation of CH4/H2 S,and CH4/CO2 mixtures was successful,while simulation demonstrated a poor result for the CH4/N2 *** effect of temperature on the diffusivity of gas is also discussed,and a correlation is introduced for diffusivity as a function of *** evaluated value for diffusivity is then used in the CFD method to investigate the permeation rate of gas mixtures.

关键词： Gas separation Silicon carbide nanosheets Molecular dynamics Computational fluid dynamics

Evaluating the characteristics of geological structures in karst groundwater inflow, Nowsud Tunnel

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Journal of Mountain Science 2024年第10期21卷 3434-3452页

作者： bayat Narges SADEGHI Erfan NASSERY Hamid Reza Department of Minerals and Groundwater Resources Faculty of Earth SciencesShahid Beheshti UniversityEvin AveTehran ***Iran Ministry of Energy Kordestan ExpyTehran ***Iran

Highly permeable geological structures such as dissolution channels, open fractures, and faults create environmental challenges regard to hydrological and hydrogeological aspects of underground construction, often causing significant groundwater inflow during drilling due to the limitations of empirical and analytical methods. This study aims to identify the geological factors influencing water flow into the tunnel. High-flow zones' geological features have been identified and examined for this purpose. According to the geological complexity of the Nowsud tunnel, presence of different formations with different permeability and karstification have led to a high volume of underground inflow water (up to 4700 L/s) to the tunnel. The Nowsud tunnel faces significant geological and hydrogeological challenges due to its passage through the Ilam formation's LI2 unit, characterized by dissolution channels, faults, and fractures. The highest inflow rate (4700 L/s) occurred in the Hz-9 zone within the Zimkan anticline. The relationship between geological features and groundwater inflow indicates that anticlines are more susceptible to inflow than synclines. Additionally, different types of faults exhibit varying hydraulic effects, with strike-slip faults having the most significant impact on groundwater inflow, thrust faults conducting less water into the tunnel, and inflow through normal faults being negligible compared to the other two types of faults. The novelty of this paper lies in its detailed analysis of geological features influencing groundwater inflow into the Nowsud tunnel, providing empirical data on high-flow zones and differentiating the hydraulic effects of various fault types, which enhances the understanding and prediction of groundwater inflow in underground constructions.

关键词： Geological structures Groundwater inflow Hydrogeology Nowsud tunnel Karst

Airborne GNSS-Receiver Threat Detection in No-Fading Environments

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Journal of Beijing Institute of Technology 2022年第6期31卷 613-620页

作者： omid Sharifi-Tehrani Department of Electrical and Communication Engineering Imam Hussein Comprehensive UniversityTehranIran.

Jamming and spoofing detection of global navigation satellite systems(GNSS)is of great *** and military aerial platforms use GNSS as main navigation systems and these systems are main target of threat *** this paper a simple method based on different empirical probability density functions of successive received signal powers and goodness of fit tech-nique is proposed for airborne platforms such as unmanned aerial vehicle(UAV),in no fading *** two different paths between UAV-satellite and UAV-threat,experience different empirical probability density functions which can be used to distinguish between authentic and threat *** results including detection and false alarm probabilities show good perfor-mance of proposed method as well as low computational burden.

关键词： detection global navigation satellite systems(GNSS) jamming spoofing unmanned aerial vehicle

Mechanism Based Pharmacokinetic Pharmacodynamic Modeling of Vildagliptin as an Add-on to Metformin for Subjects with Type 2 Diabetes

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Computer Modeling in Engineering & Sciences 2018年第2期114卷 153-171页

作者： Marziyeh Eftekhari omid Vahidi School of Chemical Petroleum and Gas EngineeringIran University of Science and TechnologyNarmakTehranIran

Various drugs are used to maintain normoglycemia in subjects with type 2 diabetes *** combination of the drugs from different classes in one single tablet may enhance the effectiveness of the anti-diabetic *** investigate the impact of combining drugs on the glucose regulation of subjects with type 2 diabetes,we propose a pharmacokinetic/pharmacodynamics(PK/PD)mathematical modeling approach for a combination of metformin and vildagliptin *** the proposed modeling approach,two separate PK models representing oral administration of metformin and vildagliptin for diabetic subjects are interconnected to a PD model comprising a detailed compartmental physiological model representing the regulatory effect of insulin,incretins and glucagon hormones on glucose concentration in a human *** impact of doses of individual drugs and their combination on the blood glucose concentration of a group of type 2 diabetic subjects is *** is indicated that while administration of individual drugs reduces the blood glucose levels,since they have separate mechanisms of action,combining them synergizes lowering the blood glucose levels.

关键词： Pharmacokinetics pharmacodynamics mathematical modeling anti-diabetic drugs metformin vildagliptin

Mobility assisted spectrum aware routing protocol for cognitive radio ad hoc networks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第11期14卷 873-886页

作者： omid ABEDI Reza BERANGI Department of Computer Engineering Iran University of Science and Technology

We propose a mobility assisted spectrum aware routing(MASAR) protocol for cognitive radio ad hoc networks(CRAHNs),providing robustness to primary user activity and node *** protocol allows nodes to collect spectrum information during a spectrum management interval followed by a transmission *** users discover next hops based on the collected spectrum and mobility *** a beaconless mechanism,nodes obtain the mobility information and spectrum status of their neighbors.A geographical routing scheme is adopted to avoid performance degradation specially due to the mobility of the nodes and the activity of the primary *** scheme uses two approaches to fnd either short or stable *** mobility metrics have a signifcant role in the selection of the next hop,both approaches use a reactive mobility update process assisted by mobility prediction to avoid location *** protocol performance is investigated through simulations of diferent scenarios and compared with that of the most similar protocol,*** results indicate that MASAR can achieve signifcant reduction in control overhead as well as improved packet delivery in highly mobile networks.

关键词： Cognitive radio Ad hoc routing Geographical routing Mobility prediction Spectrum awareness

Solving the Task Starvation and Resources Problem Using Optimized SMPIA in Cloud

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Computer Systems Science & Engineering 2022年第8期42卷 659-675页

作者： Mehran Mokhtari Homayun Motameni Peyman bayat Department of Computer Sari BranchIslamic Azad UniversitySariIran Department of Computer Rasht BranchIslamic Azad UniversityRashtIran

In this study,a new feature is added to the smart message passing interface(SMPI)approach(SMPIA)based on the prioritization method,which cancompletely eliminate the task starvation and lack of sufficient resources problemsthrough prioritizing the *** proposed approach is based on prioritizing thetasks and the urgency of *** are prioritized based on executiontime,workload,the task with a more sensitive priority is executed earlier by thefree *** idea of demand-bound functions(DBFs)was extended to theSMPIA setting based on partitions and *** each task,two DBFs are constructed,DBFLO and DBFHI,for the LO and HI criticality modes,*** simulation results returned by MATLAB showed that with the optimizedSMPIA(O-SMPIA),the parameters of maximum service execution time,response time,delay time,and throughput improved in this *** addition,the results confirmed that the reduction of execution time,completion time,andresource consumption time did not affect the response time and throughput ofworkflow tasks and did not cause inefficient use of resources in virtual machines(VMs)and data centers(DCs).The evaluation of performance metrics showedthat the delay,response time of the Greedy algorithm was less than that ofMax-Min and *** the same time,the execution time of Max-Min wasless than the others and the throughput of the Greedy was *** effectand throughput of O-SMPIA became more obvious as change to the job countand the number of cloud workloads *** is also worth mentioning thatone of the main advantages of the O-SMPIA to other methods is the efficientuse of time to execute all the defined tasks by CPU.

关键词： Cloud computing O-SMPIA task starvation EDF-VD

A benchmark system to investigate the non-minimum phase behaviour of multi-input multi-output systems

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Journal of Control and Decision 2018年第3期5卷 300-317页

作者： SaeedReza Tofighi Farshad Merrikh-bayat Department of Electrical Engineering University of ZanjanZanjanIran

In this paper,the problem of designing a multi-input multi-output(MIMO)systemfor studying the non-minimum phase(NMP)behaviour is *** this purpose,a NMP MIMO circuit is proposed and studied under different *** main reason for designing this circuit is the lack of a simple and flexible benchmark for examining different control *** to the simple structure and capability of showing different NMP characteristics,our proposed system is a suitable choice to study the behaviour of these ***,our proposed system can be extended by series and parallel connections to generate more complicated *** other advantages of this system are the large number of tunable parameters,adjustable interaction,variable number of poles and zeros,and inexpensive ***,this benchmark can be used as a tool for hardware ***,an optimal H∞decoupling control is applied to this benchmark to verify its effectiveness.

关键词： Non-minimum phase system multi-input multi-output optimal H∞decoupling control transmission zero Smith–McMillan form

Passive Behavior of Ultra-Fine-Grained 1050 Aluminum Alloy Produced by Accumulative Roll Bonding in a Borate Buffer Solution

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Acta Metallurgica Sinica(English Letters) 2015年第10期28卷 1222-1229页

作者： Arash Fattah-alhosseini Seyed omid Gashti Department of Materials Engineering Bu-Ali Sina University

In this study, the effect of the ARB process on the passive behavior of ultra-fine-grained 1050 aluminum alloy in a borate buffer solution（p H 6.0） has been investigated. The result of the microhardness tests revealed that the microhardness values increase with an increasing number of ARB cycles. The potentiodynamic polarization plots revealed that the higher number of cycles for the specimens proceeds with the ARB process rather than annealing yield to lower corrosion and passive current densities and more noble corrosion potential values. Moreover, electrochemical impedance spectroscopy measurements showed that increasing the number of ARB cycles offers better conditions for forming the passive films.

关键词： Aluminum Polarization Passivation Electrochemical impedance spectroscopy (EIS)

Simplifi ed dynamic analysis to evaluate liquefaction-inducedlateral deformation of earth slopes: a computational fluid dynamics approach

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Earthquake Engineering and Engineering Vibration 2014年第3期13卷 555-568页

作者： Yaser Jafarian Ali Ghorbani omid Ahmadi International Institute of Earthquake Engineering and Seismology P.O. Box 19395-3913 Tehran Iran Faculty of Engineering University of Guilan Rasht Iran

Lateral deformation of liquefiable soil is a cause of much damage during earthquakes, reportedly more than other forms of liquefaction-induced ground failures. Researchers have presented studies in which the liquefied soil is considered as viscous fluid. In this manner, the liquefied soil behaves as non-Newtonian fluid, whose viscosity decreases as the shear strain rate increases. The current study incorporates computational fluid dynamics to propose a simplified dynamic analysis for the liquefaction-induced lateral deformation of earth slopes. The numerical procedure involves a quasi-linear elastic model for small to moderate strains and a Bingham fluid model for large strain states during liquefaction. An iterative procedure is considered to estimate the strain-compatible shear stiffness of soil. The post-liquefaction residual strength of soil is considered as the initial Bingham viscosity. Performance of the numerical procedure is examined by using the results of centrifuge model and shaking table tests together with some field observations of lateral ground deformation. The results demonstrate that the proposed procedure predicts the time history of lateral ground deformation with a reasonable degree of precision.

关键词： liquefaction lateral ground deformation simplified dynamic analysis computational fluid dynamics