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Dynamic simulation of pilot thickener operation using phenomenological model with results validation for continuous and discontinuous tests

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Journal of Central South University 2017年第5期24卷 1207-1216页

作者： Rahimi Mehdi Unesi majid Rezai Bahram abdollahzadeh Ali Department of Mining and Metallurgical Engineering Amirkabir University of Technology Young Researchers and Elites Club Science and Research Branch Islamic Azad University Department of Mining Engineering University of Kashan

The phenomenological theory of sedimentation-thickening processes predicts the settling behavior of a flocculated suspension in dependence of two functions, the batch flux density function and the effective solid stress. These functions were determined using batch settling tests. The governing equations for sedimentation were then solved numerically for these functions and the predictions were compared to the experimental results from pilot scale thickener tests. Firstly, the continuous tests were performed in the plexiglass pilot thickener at different feed flow rates and discharge rates and the solid volume fraction of discharge, the bed height and the time were recorded for each condition. These tests were also simulated and it was observed that there is a good agreement between the results of continuous tests and the results of dynamic simulation. Secondly, the discontinuous tests were performed in the plexiglass pilot thickener at different feed flow rates with a discharge rate of zero. The bed formation rate was determined for each condition. These tests were also simulated and it was observed that there is a good agreement between the results of discontinuous tests and the results of simulation.

关键词： dynamic simulation dewatering thickener behavior pilot thickener validation

Experimental and numerical analysis of beam to column joints in steel structures

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 642-661页

作者： Gholamreza abdollahzadeh Seyed Mostafa SHABANIAN Faculty of Civil Engineering Babol Noshirvani University of TechnologyBabolIran

The behaviors such as extreme non-elastic response, constant changes in roughness and resistance, as well as formability under extreme loads such as earthquakes are the primary challenges in the modeling of beam-to-column connections. In this research, two modeling methods including mechanical and neural network methods have been presented in order to model the complex hysteresis behavior of beam-to-column connections with flange plate. First, the component-based mechanical model will be introduced in which every source of transformation has been shown only with geometrical and material properties. This is followed by the investigation of a neural network method for direct extraction of information out of experimental data. For the validation of behavioral curves as well as training of the neural network, the experiments were carried out on samples with real dimensions of beam-to-column connections with flange plate in the laboratory. At the end, the combinational modeling framework is presented. The comparisons reveal that the combinational modeling is able to display the complex narrowed hysteresis behavior of the beam-to-column connections with flange plate. This model has also been successfully employed for the prediction of the behavior of a newly designed connection.

关键词： beam to column connections experiments component method neural network model combinational modeling

Microstructure and mechanical characteristics of AA6061-T6 joints produced by friction stir welding,friction stir vibration welding and tungsten inert gas welding:A comparative study

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International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 450-461页

作者： Behrouz Bagheri Mahmoud Abbasi Amin abdollahzadeh Department of Mining and Metallurgy Amirkabir University of TechnologyTehranIran Faculty of Engineering University of KashanRavandi Blvd.KashanIran Department of Materials Science and Engineering Faculty of EngineeringShahid Chamran University of AhvazAhvazIran

This study compared the microstructure and mechanical characteristics of AA6061-T6 joints produced using friction stir welding(FSW),friction stir vibration welding(FSVW),and tungsten inert gas welding(TIG).FSVW is a modified version of FSW wherein the joining specimens are vibrated normal to the welding line during *** results indicated that the weld region grains for FSVW and FSW were equiaxed and were smaller than the grains for *** addition,the weld region grains for FSVW were finer compared with those for *** also showed that the strength,hardness,and toughness values of the joints produced by FSVW were higher than those of the other joints produced by FSW and *** vibration during FSW enhanced dynamic recrystallization,which led to the development of finer *** weld efficiency of FSVW was approximately 81%,whereas those of FSW and TIG were approximately 74%and 67%,respectively.

关键词： friction stir welding vibration tungsten inert gas welding mechanical characteristics microstructure

Proposal of a probabilistic assessment of structural collapse concomitantly subject to earthquake and gas explosion

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Frontiers of Structural and Civil Engineering 2018年第3期12卷 425-437页

作者： Gholamreza abdollahzadeh Hadi FAGHIHMALEKI Department of Civil Engineering Babol Noshirvani University of Technology Shariati Av. Babol Mazandaran Iran

In recent decades, many public buildings, located in seismic-prone residential areas, had to grapple with abnormal loads against which the structures were unguarded. In this piece of research, an ordinary three dimensional reinforced concrete building is selected as case study. The building is located in an earthquake-prone region; however, it is designed according to seismic building codes. Yet, it is not shielded against abnormal loads, such as blasts. It is assumed that the building suffers a blast load, due to mechanical/thermal installation failure during or after intense seismic oscillations. These two critical incidents are regarded codependent and compatible. So the researchers developed scenarios and tried to assess different probabilities for each scenario and carried out an analysis to ensure if progressive collapse had set in or not. In the first step, two analysis models were used for each scenario; a non-linear dynamic time history analysis and a blast local dynamic analysis. In the second step, having the structural destructions of the first step in view, a pushdown analysis was carried out to determine the severity of progressive collapse and assess building robustness. Finally, the annual probability of structural collapse under simultaneous earthquake and blast loads was estimated and offered.

关键词： gas blast pushdown analysis progressive collapse annual probability of structural collapse 3D model of structure

Anaerobic-aerobic processes for the treatment of textile dyeing wastewater containing three commercial reactive azo dyes:Effect of number of stages and bioreactor type

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Chinese Journal of Chemical Engineering 2021年第11期34卷 228-239页

作者： Banafsheh Azimi Elham abdollahzadeh-Sharghi Babak Bonakdarpour Chemical Engineering Department Amirkabir University of TechnologyTehranIran Environmental Group Energy DepartmentMaterials and Energy Research CenterAlborzIran

In this study,the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was *** stage processes performed better than one stage ones,both in terms of overall organic and color removal,as well as the higher contribution of anaerobic stage to the overall removal performance,thereby making them a more energy efficient *** employment of a moving bed sequencing batch biofilm reactor,which uses both suspended and attached biomass,for the implementation of the anaerobic stage of the process,was compared with a sequencing batch reactor that only employs suspended *** results showed that,although there was no meaningful difference in biomass concentration between the two bioreactors,the latter reactor had better performance in terms of chemical oxygen demand(COD)removal efficiency and rate and color removal *** exploratory tests revealed a difference between the roles of suspended and attached bacterial populations,with the former yielding better color removal whilst the latter had better COD removal *** sequential anaerobic–aerobic process,employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9%and 79.9±1.5%,*** incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites,***,aerobic partial mineralization of the dye reduction metabolites,was experimentally observed.

关键词： Wastewater Anaerobic Aerobic Anaerobic moving bed sequencing batch biofilm reactor Anaerobic sequencing batch reactor Aerobic membrane bioreactor

A comparative study between friction stir processing and friction stir vibration processing to develop magnesium surface nanocomposites

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International Journal of Minerals,Metallurgy and Materials 2020年第8期27卷 1133-1146页

作者： Behrouz Bagheri Mahmoud Abbasi Amin abdollahzadeh Amir Hossein Kokabi Department of Mining and Metallurgy Amirkabir University of TechnologyTehranIran Faculty of Engineering University of KashanRavandi Blvd.KashanIran Department of Materials Science and Engineering Sharif University of TechnologyTehranIran Institute of Materials Engineering and Advanced Processes Department of Mining and MetallurgyAmirkabir University of TechnologyTehranIran

Friction stir processing(FSP)can be used to improve surface *** this study,a modified method of FSP called friction stir vibration processing(FSVP)was applied to develop a surface composite on AZ91 magnesium *** this technique,the workpiece is vibrated normal to the processing *** results illustrated that compared with the FSP method,the FSVP caused a better homogeneous distribution of SiC particles in the *** results also showed that matrix grains of friction stir vibration processed(FSV-processed)samples((26.43±2.00)μm)were finer than those of friction stir processed(FS-processed)specimens((39.43±2.00)μm).The results indicated that the ultimate tensile strength(UTS)of FSV-processed specimens(361.82 MPa)was higher than that of FS-processed specimens(324.97 MPa).The higher plastic strain in the material during FSVP,due to workpiece vibration,resulted in higher dynamic recrystallization,and consequently,finer grains were *** elongation and formability index of the FSV-processed specimen(16.88%and 6107.52 MPa·%,respectively)were higher than those of the FS-processed sample(15.24%and 4952.54 MPa·%,respectively).Moreover,the effects of FSVP were also found to intensify as the vibration frequency increased.

关键词： friction stir processing friction stir vibration processing surface composite mechanical properties microstructure

Urban microclimate and energy consumption:A multi-objective parametric urban design approach for dense subtropical cities

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Frontiers of Architectural Research 2022年第3期11卷 453-465页

作者： Nastaran abdollahzadeh Nimish Biloria Faculty of Design Architecture and Building University of Technology SydneySydneyAustralia Faculty of Engineering and the Built Environment University of JohannesburgJohannesburgSouth Africa

Climate change within the urban contexts is a crisis that cities are confronting *** issue poses numerous negative consequences such as thermal discomfort and increased energy usage within the building *** is especially the case in Western Sydney,Australia,where the average maximum temperature has risen by 7—8℃ within the past 30 *** increase in temperature is highly concerning,since this region is witnessing rapid urban and infrastructural development and is proposed as the third-largest economy of *** changes in this region will also result in considerably increasing the electricity used for cooling *** paper presents a parametric approach driven multi-objective optimization methodology to discover optimum design solution based on the urban microclimate and cooling energy demand of multi-functional buildings within this urban *** measures including a range of design factors at both building(typology and window to wall ratio)and urban scales(aspect ratio and urban grid rotation)are further suggested for developing context sensitive optimum urban *** resultant solutions indicate an improvement in urban thermal comfort,cooling and heating energy use by up to 25.85%,72.76%,and 93.67%,respectively.

关键词： Urban microclimate Energy consumption Parametric design Urban layout optimization Architecture Urban planning

Outdoor thermal comfort: Analyzing the impact of urban configurations on the thermal performance of street canyons in the humid subtropical climate of Sydney

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Frontiers of Architectural Research 2021年第2期10卷 394-409页

作者： Nastaran abdollahzadeh Nimish Biloria Shahid Beheshti University TehranIron Faculty of Design Architecture and Buildins University of Technology SydneySydneyNSWAustralia

The quality of outdoor space is becoming increasingly important with the growing rate of ***,acoustic,and thermal balance degradation are all negative impacts associated with outdoor comfort in dense urban *** morphology thus needs assessment and optimization to ensure favorable outdoor thermal comfort(OTC).This study aims to evaluate the thermal performance of streets in residential zones of Liverpool,NSW,Australia,and tries to improve their comfort index(Physiological Equivalent Temperature)to reveal optimum urban *** evaluation is done by investigating the following urban design factors affecting OTC using computational simulation techniques:street orientation,aspect ratio,building typology,and surface *** findings reveal that street canyon orientation is the most influential factor(46.42%),followed by aspect ratio(30.59%).Among the influential meteorological parameters(air temperature,wind speed,humidity and solar radiation),wind velocity had the most significant impact on the thermal comfort of the outdoor spaces in this coastal region,which typically experiences intense *** results of our analysis can be utilized by multiple stakeholders,allowing them to understand and extract the most vital design factors which contextually influence the thermal comfort of outdoor *** thermal comfort has a direct effect on the health and wellbeing of occupants of outdoor spaces.

关键词： Outdoor comfort Thermal sensation Urban configuration Street canyons Architecture

An Improved Farmland Fertility Algorithm with Hyper-Heuristic Approach for Solving Travelling Salesman Problem

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Computer Modeling in Engineering & Sciences 2023年第6期135卷 1981-2006页

作者： Farhad Soleimanian Gharehchopogh Benyamin abdollahzadeh Bahman Arasteh Department of Computer Engineering Urmia BranchIslamic Azad UniversityUrmiaIran Department of Software Engineering Faculty of Engineering and Natural ScienceIstinye UniversityIstanbulTurkey

Travelling Salesman Problem(TSP)is a discrete hybrid optimization problem considered *** aims to discover the shortest Hamilton route that visits each city precisely once and then returns to the starting point,making it the shortest route *** paper employed a Farmland Fertility Algorithm(FFA)inspired by agricultural land fertility and a hyper-heuristic technique based on the Modified Choice Function(MCF).The neighborhood search operator can use this strategy to automatically select the best heuristic method formaking the best ***-Kernighan(LK)local search has been incorporated to increase the efficiency and performance of this suggested approach.71 TSPLIB datasets have been compared with different algorithms to prove the proposed algorithm’s performance and *** results indicated that the proposed algorithm outperforms comparable methods of average mean computation time,average percentage deviation(PDav),and tour length.

关键词： Travelling salesman problem optimization farmland fertility optimization algorithm Lin-Kernighan