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Simplified Method and Influence Factors of Vibration Characteristics of Isolated Curved Girder Bridge

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Structural Durability & Health Monitoring 2018年第3期12卷 189-212页

作者： Tongfa Deng Junping Zhang mahmoud bayat Guangzhou University-Tamkang University Joint Research Center for Engineering Structure Disaster Preventioand Control Guangzhou UniversityGuangzhou510006China Jiangxi Provincial Key Laboratory of Environmental Geotechnical Engineering and Disaster Control Jiangxi University of Science and TechnologyGanzhouJiangxi341000China Guangdong Communication Polytechnic Guangzhou510170China Young Researchers and Elite Club Roudehen BranchIslamic Azad UniversityRoudehenIran

The isolated curved girder bridge's vibration characteristics play a major part in the seismic responses of structures and anti-seismic properties.A clear analytic relationship between design parameters and the system's vibration characteristics could be established by its simplified dynamic analysis model,making it convenient for providing a reference to the optimization of design and safety analysis.A double-mass six-degree-of-freedom model for curved girder bridges with isolation bearings installed at the top of the bridge piers is built and a simplified analysis method for the vibration characteristics of the system is *** with the Matlab programming,the influences of radius of curvature,central angle,bridge deck width and damping ratio of the isolation layer and circular frequency of the isolation layer of isolated curved girder bridges on the pseudo-undamped natural circular frequency(called pseudo-frequency for short)and system damping ratio are systematically analyzed,and the sensitivity of vibration characteristics of isolated curved girder bridges is *** results show that the vibration characteristics of isolated curved girder bridges can be reflected well with this simplified model and calculation *** pseudo-frequency of curved girder and system damping ratios increases with the increase of the isolation *** third-order vibration characteristic is more sensitive to the parameters of a curved girder,and the first-order vibration characteristic is sensitive to both central angle and radius of curvature to some extent while insensitive to the width of the bridge ***,the second-order vibration characteristic is not sensitive to the parameters of a curved girder.

关键词： Seismic isolation curved girder bridge vibration characteristics sensitivity analysis simplified analysis method

Mixture temperature prediction of waxy oil–water two-phase system flowing near wax appearance temperature

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Chinese Journal of Chemical Engineering 2016年第6期24卷 795-802页

作者： Ali Piroozian Muhammad A. Manan Issham Ismail Rahmat Mohsin Ali Esfandyari bayat Mac DarlingtonUche Onuoha mahmoud Hemmati Department of Petroleum Engineering Faculty of Petroleum and Renewable Energy Engineering Universiti Teknologi Malaysia Johor 81310 Malaysia Malaysia Petroleum Resources Corporation (UTM-MPRC) Institute for Oil and Gas Universiti Teknologi MalaysiaJohor 81310 Malaysia ffshore Oil and Gas Research Center College of Mechanical and Oil/Gas Transportation Engineering China University of Petroleum Beijing 102249 China

Temperature sensitivity of waxy crude oils makes it difficult to study their flow behaviour in the presence of water especially near their wax appearance temperature （WAT）. In this study a method was proposed and implemented to mitigate such difficulties which was applied in predicting mixture temperatures （Tin） of a typical Malaysian waxy crude oil and water flow in a horizontal pipe. To this end, two analytical models were derived firstly from calorimetry equation which based on developed two correlations for defining crude oil heat capacity actualized from the existed specific heat capacities of crude oils. The models were then applied for a set of experiments to reach the defined three predetermined Tm （26 ℃, 28 ℃ and 30 ℃）. The comparison between the predicted mixture temperatures （Tin,1 and Tin,2） from the two models and the experimental results displayed acceptable absolute average errors （0.80% 0.62%, 0.53% for model 1; 0,74%, 0.54%, 0.52% for model 2）. Moreover, the average errors for both models are in the range of standard error limits （4-0,75Z） according to ASTM E230. Conclusively, the proposed model showed the ease of obtaining mixture temperatures close to WAT as predetermined with accuracy of ± 0.5 ℃approximately for over 84% of the examined cases. The method is seen as a practical reference point to further study the flow behaviour of waxy crudes in oil-water two-phase flow system near sensitive temperatures.

关键词： Mixture temperature predictionAnalytical modelWaxy oil-water two-phase flowWax appearance temperature

Correlating thermal conductivity of pure hydrocarbons and aromatics via perceptron artificial neural network (PANN) method

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Chinese Journal of Chemical Engineering 2017年第5期25卷 547-554页

作者： Mostafa Lashkarbolooki Ali Zeinolabedini Hezave Mahdi bayat School of Chemical Engineering Babol University of Technology Islamic Azad University Dashtestan Branch Department of Chemical Engineering Faculty of EngineeringUniversity of Bojnord

Accurate estimation of liquid thermal conductivity is highly necessary to appropriately design equipments in different industries. Respect to this necessity, in the current investigation a feed-forward artificial neural network(ANN) model is examined to correlate the liquid thermal conductivity of normal and aromatic hydrocarbons at the temperatures range of 257–338 K and atmospheric pressure. For this purpose, 956 experimental thermal conductivities for normal and aromatic hydrocarbons are collected from different previously published *** the modeling stage, to discriminate different substances, critical temperature(Tc), critical pressure(Pc)and acentric factor(ω) are utilized as the network inputs besides the temperature. During the examination, effects of different transfer functions and number of neurons in hidden layer are investigated to find the optimum network architecture. Besides, statistical error analysis considering the results obtained from available correlations and group contribution methods and proposed neural network is performed to reliably check the feasibility and accuracy of the proposed method. Respect to the obtained results, it can be concluded that the proposed neural network consisted of three layers namely, input, hidden and output layers with 22 neurons in hidden layer was the optimum ANN model. Generally, the proposed model enables to correlate the thermal conductivity of normal and aromatic hydrocarbons with absolute average relative deviation percent(AARD), mean square error(MSE), and correlation coefficient(R^2) of lower than 0.2%, 1.05 × 10^(-7) and 0.9994, respectively.

关键词： Thermal conductivity Artificial neural network Critical properties Hydrocarbons Aromatics

Soil evolution along an alluvial-loess transect in the Herat Plain,western Afghanistan

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Journal of Arid Land 2022年第11期14卷 1317-1330页

作者： Farsila mahmoudIAN Alireza KARIMI Omid bayat Department of Soil Science Faculty of AgricultureHerat UniversityHerat 3001-272806Afghanistan Department of Soil Science Faculty of AgricultureFerdowsi University of MashhadMashhad ***Iran

Afghanistan is located in the Eurasian loess belt,however,there is little information on the soils in the *** has covered the Herat Plain in western Herat City,*** the diversity of landform and parent material,there is no information on the soil and landform evolution in this *** objectives of this study were to identify the soils along a transect of different landforms in the Herat Plain and determine the role of geomorphic processes on the soil and landform *** pedons from an alluvial fan,the depression between alluvial fan and piedmont plain,saline and non-saline piedmont plains,and the flood plain of the Hariroud River,were ***,the physical-chemical properties,mineralogy,and micromorphology of the samples were *** showed that the soil parent material in the piedmont plain is loess,whereas,in the flood plain it is a combination of loess and river alluvial ***,lessivage,salinization,and gleization are the most important pedogenic *** calcification and lessivage appear to be the result of a wetter climate during the late Quaternary,whereas the present topography causes the gleization and *** coatings on carbonate nodules and iron nodules are abundant pedofeatures in the Btk(argillic-calcic)*** oxides nodules are common in the soils of the flood *** formation of palygorskite in both alluvial-and loess-derived soils implies the onset of aridity and the trend of increase in environmental aridity in the *** seems that after the formation of a well developed paleosol on the alluvial fan in a more humid climate in the past,the piedmont plain has been covered by loess deposits,and the calcification,gleization,and salinization cause the formation of weakly developed surficial *** study highlights the role of the late Quaternary climatic changes on the evolution of landforms and soils in western Afghanistan.

关键词： alluvial fan loess-derived soils paleosol gleization Hariroud River

Graphene quantum dots decorated rutile TiO_2 nanoflowers for water splitting application

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Journal of Energy Chemistry 2018年第1期27卷 306-310页

作者： A.bayat E.Saievar-Iranizad Department of physics Faculty of Basic Science Tarbiat Modares University

Flower like rutile TiO_2 films were decorated with green-photoluminescent graphene quantum dots（GQDs） and photovoltaic properties were investigated for water splitting application. Rutile TiO_2 nanoflowers（NFs） and GQDs（average width of^12 nm） synthesized separately using a hydrothermal method and TiO_2 NFs were decorated with various amounts of GQDs solution（x = 5, 10, 15 and 20 μL） by spin coating. Optical characterization reveals that GQDs are highly luminescent and absorb UV and visible light photons with wavelengths up to 700 nm. GQDs-x/TiO_2 electrode shows a photocurrent enhancement of ~95% compared to pristine TiO_2 NFs for the optimum sample（x = 15 μL） at an applied potential of P = 0 V using 1 M Na_2SO_4 solution as electrolyte.

关键词： Graphene quantum dotsTiO2 nanoflowers Water splitting Photoanode

Robust non-aggressive three-axis attitude control of spacecraft:dynamic sliding mode approach

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Control Theory and Technology 2023年第4期21卷 505-514页

作者： Javad Nikyar Farhad bayat MohammadAli Mohammadkhani Department of Electrical Engineering University of ZanjanUniversity Blvd.ZanjanZanjan***Iran Department of Electrical Engineering Technical and Vocational UniversityBrazil St.TehranTehran***Iran

Conventional sliding mode control(SMC)has been extensively applied in controlling spacecrafts because of its appealing characteristics such as robustness and a simple design *** methods such as second-order sliding modes and discontinuous controllers are applied for the SMC ***,the main problems of these methods are convergence and error tracking in a finite amount of *** paper combines an improved dynamic sliding mode controller and model predictive controller for spacecrafts to solve the chattering phenomenon in traditional sliding mode *** this aim,this paper develops dynamic sliding mode control for spacecraft’s applications to omit the chattering *** proposed approach shows robust attitude tracking by a set of reaction wheels and stabilizes the spacecraft subject to disturbances and *** proposed method improves the performance of the SMC for spacecraft by avoiding chattering.A set of simulation results are provided that show the advantages and improvements of this approach(in some sense)compared to SMC approaches.

关键词： Dynamic sliding mode control Attitude control Model predictive control Spacecrafts

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

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