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磁性微碳球改性材料修复Pb污染土壤的影响因素与作用机理

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科技创新与应用 2024年第12期14卷 16-19页

作者：韩秋凤赵庆令王辉花逢春李清彩高翔张莹莹 Ahsan maqbool 山东省鲁南地质工程勘察院山东省地质矿产勘查开发局第二地质大队山东济宁272100 中国矿业大学环境与测绘学院江苏徐州221116 山东省鲁南地质工程勘察院自然资源部采煤沉陷区综合治理与生态修复工程技术创新中心山东济宁272100 西班牙高等科研理事会可持续农业研究所西班牙科尔多瓦14004

Pb(Ⅱ)是有毒重金属,被世界卫生组织国际癌症研究机构列为一类致癌物,如何从土壤中去除Pb是土壤污染修复中的重要课题。该文采用水热合成法制备磁性陶粒负载微碳球并经聚乙二醇改性功能材料MCCSPG用于土壤Pb污染修复。结果表明,MCCSPG... 详细信息

Pb(Ⅱ)是有毒重金属,被世界卫生组织国际癌症研究机构列为一类致癌物,如何从土壤中去除Pb是土壤污染修复中的重要课题。该文采用水热合成法制备磁性陶粒负载微碳球并经聚乙二醇改性功能材料MCCSPG用于土壤Pb污染修复。结果表明,MCCSPG对土壤Pb具有很好的吸附去除效果,总Pb平均去除率为94.11%,有效态Pb去除率达95%以上。在影响土壤Pb去除率的因素中,材料投加量、作用时间和土壤Pb初始含量在吸附平衡之前与去除率均为正比关系,而pH为弱酸性时去除率大,pH为4.9时吸附量最大,材料的最大吸附容量可达48 mg/g。MCCSPG对土壤中Pb不仅存在化学吸附,还有相当数量的物理吸附,吸附过程符合Freundlich等温吸附和准一级动力学模型。吸附上升阶段持续时间长、吸附量起点低,材料投入土壤吸附Pb需要12 d以上达最大吸附量。

关键词：磁性陶粒微碳球改性材料 Pb污染土壤污染修复

On subsurface box-shaped lined tunnel under incident SH-wave propagation

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Frontiers of Structural and Civil Engineering 2021年第4期15卷 948-960页

作者： mehdi PANJI Saeed MOJTABAZADEH-HASANLOUEI Department of Civil Engineering Zanjan BranchIslamic Azad UniversityZanjan45156-58145Iran

In this paper,a half-plane time-domain boundary element method is applied to obtain the seismic ground response,including a subsurface box-shaped lined tunnel deployed in a linear homogenous elastic medium exposed to obliquely incident *** the boundary around the tunnel is required to be *** prepare an appropriate model by quadratic elements,a double-node procedure is used to receive dual boundary fields at corners as well as change the direction of the normal *** encoding the method in a previously confirmed computer program,a numerical study is carried out to sensitize some effective parameters,including frequency content and incident wave angle for obtaining a surface *** depth and impedance ratio of the lining are assumed to be *** responses are illustrated in the time and frequency domains as two/three-dimensional *** results showed that subsurface openings with sharp corners distorted the propagation path of the anti-plane waves to achieve the critical states on the ground *** present approach can be proposed to civil engineers for preparing simple underground box-shaped models with angular boundaries.

关键词： box-lined tunnel half-plane BEM surface response SH-wave time-domain

On the dynamically formed oxide films in molten Mg

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Journal of Magnesium and Alloys 2020年第1期8卷 219-230页

作者： Mohammad Mahdi Jalilvand mehdi Akbarifar mehdi Divandari Hassan Saghafian School of Metallurgy and Materials Engineering Iran University of Science and Technology(IUST)NarmakTehran16846-13114Iran

The so-called“Oxide/Metal/Oxide sandwich”method is one of the technique used to investigate the dynamic oxidation of metals which happens during the casting *** this study,characteristics of the oxide films formed on the molten magnesium in dynamic conditions have been investigated using the aforementioned *** air bubbles were released into the cast sample at the pressure of 0.2 atm through a quartz tube of 1 mm internal *** interface of two adjacent entrapped bubbles is considered as the Oxide/Metal/Oxide(OMO)*** sandwiches were characterized by the aid of the optical and scanning electron microscopy and also X-Ray diffraction *** different approaches,including measuring the width of the folds formed on the oxide films and the edge of the sandwiches,were used to estimate the thickness of the *** thicknesses were estimated to be in the range of 200 to 800 *** features such as fold,wrinkle,and crack were observed on the OMO *** the microscopic scale,the oxide films were rough and *** is attributed to the non-protective behavior of oxide *** XRD patterns indicated that the oxide films formed on the pure molten magnesium in dynamic conditions are crystallized MgO.

关键词： Dynamic oxidation Bifilm Magnesium Oxide films Casting defects

Robust Control of Robotic Manipulators in the Task-Space Using an Adaptive Observer Based on Chebyshev Polynomials

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Journal of Systems Science & Complexity 2020年第5期33卷 1360-1382页

作者： GHOLIPOUR Reza FATEH Mohammad mehdi Department of Electrical and Robotic Engineering Shahrood University of Technology*** ShahroodIran

In this paper,an adaptive observer for robust control of robotic manipulators is *** lumped uncertainty is estimated using Chebyshev ***,the uncertainty upper bound is required in designing observer-controller ***,obtaining this bound is a challenging *** solve this problem,many uncertainty estimation techniques have been proposed in the literature based on neuro-fuzzy *** an alternative,in this paper,Chebyshev polynomials have been applied to uncertainty estimation due to their simpler structure and less computational *** on strictly-positive-rea Lyapunov theory,the stability of the closed-loop system can be *** Chebyshev coefficients are tuned based on the adaptation rules obtained in the stability ***,to compensate the truncation error of the Chebyshev polynomials,a continuous robust control term is designed while in previous related works,usually a discontinuous term is *** SCARA manipulator actuated by permanent magnet DC motors is used for computer *** results reveal the superiority of the designed method.

关键词： Adaptive observer Chebyshev polynomials electrically driven robot manipulators robust control uncertainty estimation

Strain hardening behavior, strain rate sensitivity and hot deformation maps of AISI 321 austenitic stainless steel

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International Journal of Minerals,Metallurgy and Materials 2021年第11期28卷 1799-1810页

作者： mehdi Shaban Ghazani Beitallah Eghbali Department of Materials Science Engineering University of BonabBonab***Iran Faculty of Materials Engineering Sahand University of TechnologyTabriz51335-1996Iran

Hot compression tests were performed on AISI 321 austenitic stainless steel in the deformation temperature range of 800–1200℃ and constant strain rates of 0.001,0.01,0.1,and 1 s^(−1).Hot flow curves were used to determine the strain hardening exponent and the strain rate sensitivity exponent,and to construct the processing *** of the strain hardening exponent with strain were used to predict the microstructural evolutions during the hot *** variations were distinguished reflecting the different microstructural *** on the analysis of the strain hardening exponent versus strain curves,the microstructural evolutions were dynamic recovery,single and multiple peak dynamic recrystallization,and interactions between dynamic recrystallization and *** strain rate sensitivity variations at an applied strain of 0.8 and strain rate of 0.1 s^(−1) were compared with the microstructural *** results demonstrate the existence of a reliable correlation between the strain rate sensitivity values and evolved ***,the power dissipation map at the applied strain of 0.8 was compared with the resultant microstructures at predetermined deformation *** microstructural evolutions strongly correlated to the power dissipation ratio,and dynamic recrystallization occurred completely at lower power dissipation ratios.

关键词： strain hardening strain rate sensitivity processing map AISI 321 austenitic stainless steel hot compression

Application of Bernstein polynomials for solving Fredholm integro-differential-difference equations

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Applied Mathematics(A Journal of Chinese Universities) 2022年第4期37卷 475-493页

作者： Esmail Hesameddini mehdi Shahbazi Department of Mathematics Sciences Shiraz University of TechnologyP.O.Box 71555-313ShirazIran

In this paper,the Bernstein polynomials method is proposed for the numerical solution of Fredholm integro-differential-difference equation with variable coefficients and mixed *** method is using a simple computational manner to obtain a quite acceptable approximate *** main characteristic behind this method lies in the fact that,on the one hand,the problem will be reduced to a system of algebraic *** the other hand,the efficiency and accuracy of the Bernstein polynomials method for solving these equations are *** existence and uniqueness of the solution have been ***,an estimation of the error bound for this method will be shown by preparing some ***,some numerical experiments are presented to show the excellent behavior and high accuracy of this algorithm in comparison with some other well-known methods.

关键词： Fredholm integro-differential-difference equation Bernstein polynomials existence and uniqueness error estimate

HALOMETHYLATION OF POLYSTYRENE AND SUBSEQUENT PYRIDINATION VIA A HOMOLYTIC PATHWAY

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Chinese Journal of Polymer Science 2006年第6期24卷 627-635页

作者： Sad Moulay Nadia mehdi Laboratoire de Chimie-Physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Departement de Chimie IndustrielleUniversité de BlidaRoute de SoumaB. P. 270Blida 09000Algeria

Chloromethylation of polystyrene （PS） with two different chloromethylating systems methylal/thionyl chloride and paraformaldehyde/trimethylchlorosilane was studied. Soluble chloromethylated polystyrene with a degree of substitution of 89% was obtained. The Conant-Finkelstein reaction on the chloromethylated PS afforded soluble iodomethylated polystyrene with a degree of substitution as high as 96%. The reaction conditions of Minisci were employed to radically pyridinate PS via its iodomethylated derivative. Polyelectrolytes were formed which could be converted to normal polymers by treatment with a 20% aqueous solution of NaOH.

关键词： Chloromethylated polystyrene Conditions of Minisci Iodomethylated polystyrene Pyridinated polystyrene.

An Efficient Two-Phase Model for Computing Influential Nodes in Social Networks Using Social Actions

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Journal of Computer Science & Technology 2018年第2期33卷 286-304页

作者： mehdi Azaouzi Lotfi Ben Romdhane Modeling of Automated Reasoning Systems Research Laboratory LR17ES05 Higher Institute of Computer Science and Telecom University of Sousse Sousse 526-~002 Tunisia

The measurement of influence in social networks has received a lot of attention in the data mining community. Influence maximization refers to the process of finding influential users who make the most of information or product adoption. In real settings, the influence of a user in a social network can be modeled by the set of actions （e.g., ＂like＂, ＂share＂, ＂retweet＂, ＂comment＂） performed by other users of the network on his/her publications. To the best of our knowledge, all proposed models in the literature treat these actions equally. However, it is obvious that a ＂like＂ of a publication means less influence than a ＂share＂ of the same publication. This suggests that each action has its own level of influence （or importance）. In this paper, we propose a model （called Social Action-Based Influence Maximization Model, SAIM） for influence maximization in social networks. In SAIM, actions are not considered equally in measuring the ＂influence power＂ of an individual, and it is composed of two major steps. In the first step, we compute the influence power of each individual in the social network. This influence power is computed from user actions using PageRank. At the end of this step, we get a weighted social network in which each node is labeled by its influence power. In the second step of SAIM, we compute an optimal set of influential nodes using a new concept named ＂influence-BFS tree＂. Experiments conducted on large-scale real-world and synthetic social networks reveal the good performance of our model SAIM in computing, in acceptable time scales, a minimal set of influential nodes allowing the maximum spreading of information.

关键词： social network social influence social action personalized PageRank influence-BFS tree

Modeling flame propagation speed and quenching distance of aluminum dust flame with spatially random distribution of particles

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Journal of Central South University 2017年第1期24卷 81-89页

作者： mehdi Bidabadi Alireza Khoeini Poorfar Combustion Research Laboratory School of Mechanical EngineeringIran University of Science and Technology(IUST)Narmak16846-13114TehranIran

In this research combustion of aluminum dust particles in a quiescent medium with spatially discrete sources distributed in a random way was studied by a numerical approach.A new thermal model was generated to estimate flame propagation speed in a lean/rich reaction *** speed for different particle diameters and the effects of various oxidizers such as carbon dioxide and oxygen on flame speed were *** was considered the inert *** addition,the quenching distance and the minimum ignition energy(MIE) were studied as a function of dust *** burning time models for aluminum were employed and their results were compared with each *** model was based on conduction heat transfer mechanism using the heat point source *** combustion of single-particle was first studied and the solution was *** the dust combustion was investigated using the superposition principle to include the effects of surrounding *** is found that larger particles have higher values of quenching distance in comparison with smaller particles in an assumed dust *** the increase of dust concentration the value of MIE would be decreased for an assumed particle *** random discrete heat sources method,the obtained results of random distribution of fuel particles in space provide closer and realistic predictions of the combustion physics of aluminum dust flame as compared with the experimental findings.

关键词： flame propagation speed random particle distribution quenching distance random discrete combustion aluminum