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Frontiers of Structural and Civil Engineering 2015年第1期9卷 91-103页

作者： mahdi arezoumandi Department of Civil Architectural and Environmental Engineering Missouri University of Science and Technology 212 ButlerCarlton Hall 1401 N. Pine Street Rolla MO 65409 USA

Early age cracking on bridge deck has been the subject of many studies for years. Cracking is a major concern because it leads to premature deterioration of structures. Millions of dollars spent to repair the cracked bridge decks each year. To design an appropriate mixture for crack free bridge deck, it is important to study previous researches. This paper presents a comprehensive literature review of the performance of different materials compositions as well as methods have been used to reduce and control bridge deck cracks. Different material compositions and methods are discussed in terms of their performances as well as advantages and disadvantages.

关键词： bridge deck crack fiber shrinkage shrinkage reducing admixture

Effect of fly ash replacement level on the fracture behavior of concrete

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Frontiers of Structural and Civil Engineering 2013年第4期7卷 411-418页

作者： mahdi arezoumandi Jeffery SVOLZ Department of Civil Architectural and Environmental EngineeringMissouri University of Science and TechnologyRolla MO 65409USA

The production of portland cement–the key ingredient in concrete–generates a significant amount of carbon ***,due to its incredible versatility,availability,and relatively low cost,concrete is the most consumed manmade material on the *** method of reducing concrete’s contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the *** study presents the results of an experimental investigation that evaluates effect of fly ash replacement level on the fracture energy of *** study includes four mixes with 0%,30%,50%,and 70%fly ash as a cement *** experimental program consisted of 32 fracture beams to study the fracture behavior of *** experimental fracture energies were compared with the fracture energy provisions of different design codes and also different analytical ***,statistical data analyses(parametric and non-parametric)were performed to evaluate whether or not there is any statistically significant difference between the experimental fracture energies of different *** of these statistical tests show that the mix with higher level of fly ash replacement level has higher fracture energy.

关键词： concrete fracture energy fly ash

A comparative study of the mechanical properties, fracture behavior, creep, and shrinkage of chemically based self-consolidating concrete

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Frontiers of Structural and Civil Engineering 2014年第1期8卷 36-45页

作者： mahdi arezoumandi Mark EZZELL Jeffery S VOLZ Department of Civil Architectural and Environmental Engineering Missouri University of Science and Technology Missouri MO 65409 USA U S Army Corps of Engineers 1222 Spruce St. St. Louis Missouri MO 63103 USA School of Civil Engineering and Environmental Science University of Oklahoma Norman OK 73019-1024 USA

This study presents the results of an experimental investigation that compares the mechanical properties, fracture behavior, creep, and shrinkage of a chemically-based self-consolidating concrete （SCC） mix with that of a corresponding conventional concrete （CC） mix. The CC and SCC mix designs followed conventional proportioning in terms of aggregate type and content, cement content, air content, water-cementitiuos materials （w/cm） ratio, and workability. Then, using only chemical admixtures, the authors converted the CC mix to an SCC mix with all of the necessary passing, filling, flowability, and stability requirements typically found in SCC. The high fluidity was achieved with a polycarboxylate-based high-range water-reducing admixture, while the enhanced stability was accomplished with an organic, polymer-based viscosity-modifying admixture. The comparison indicated that the SCC and CC mixes had virtually identical tensile splitting strengths, flexural strengths, creep, and shrinkage. However, the SCC mix showed higher compressive strengths and fracture energies than the corresponding CC mix.

关键词： admixture conventional concrete (CC) creep fracture mechanic mechanical Properties self-consolidatingconcrete (SCC) shrinkage

基于均值和标准差的高速公路行程时间可靠性预测

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交通运输系统工程与信息 2011年第6期11卷 74-84页

作者： arezoumandi mahdi 密苏里科学技术大学土木建筑与环境工程学院罗拉MO65409-0440美国

在密苏里州圣路易斯市I-270/I-255州际公路上,可变限速标志实时控制高峰期车速以缓解拥堵.本文研究可变限速系统对行程时间分布和可靠性的影响,分析伽马分布、最大极值分布l、og-logistic概率分布、对数正态分布及威布尔分布与24小时行... 详细信息

在密苏里州圣路易斯市I-270/I-255州际公路上,可变限速标志实时控制高峰期车速以缓解拥堵.本文研究可变限速系统对行程时间分布和可靠性的影响,分析伽马分布、最大极值分布l、og-logistic概率分布、对数正态分布及威布尔分布与24小时行程时间数据的拟合程度,得到后可变限速情形下行程时间的分布.结果表明,后可变限速情形下行程时间的分布服从对数正态分布.提出基于行程时间均值和标准差方法计算行程时间可靠性最关键指标之一——第95百分位数的行程时间.基于I-270/I-255公路四个拥堵路段36个实测数据集,用参数和非参数统计验证了方法的有效性.

关键词：公路运输可变限速行程时间行程时间分布行程时间可靠性对数正态分布

An experimental investigation on the effect of grain size on oil-well sand production

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Petroleum Science 2012年第3期9卷 343-353页

作者： Vahidoddin Fattahpour mahdi Moosavi mahdi Mehranpour School of Mining Engineering the University of Tehran

Sand production in oil wells is closely related to the mechanical behavior and petrographical properties of sandstones reservoir. Grain size is one of the main parameters controlling the phenomenon, which is studied in this paper. Large-scale hollow cylindrical synthetic samples with the same rock strength but different grain sizes were tested by an experimental setup in the laboratory. Different external stresses and fluid flow rates were applied to the samples and produced sand was measured continuously. Results show two different trends between sanding stress level and grain size. For the samples with finer grain size （D50〈0.3 mm）, the required confining stress for different sanding levels decreased with an increase in the grain size and for the samples with the coarser grains （D50〉0.3 mm） the required confining stress for different sanding levels dramatically increased with an increase in the grain size. Those two different trends were discussed and explained. The first one was production of individual grains and the second was bigger chunks in the slab form. In samples with large grains, plastic zones around hole were changed to a completely loose zone including interlocked individual grains or cluster of grains. In these samples after breakage of these interlocked zones sand was produced in the form of individual grains and clusters. Contrary to this, for samples with smaller grain size, shear bands were formed around the plastified hole and sand was produced in the form of big chunks or slabs.

关键词： Sand production experimental tests grain size perforation size

Initial estimation of hydrate formation temperature of sweet natural gases based on new empirical correlation

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Journal of Natural Gas Chemistry 2012年第5期21卷 508-512页

作者： Mohammad mahdi Ghiasi Petroleum University of Technology Ahwaz Faculty of PetroleumPost Box:63431AhwazIran

Production,processing and transportation of natural gases can be significantly affected by clathrate *** the gas analysis is crucial to predict the right conditions for hydrate ***,Katz gas gravity method can be used for initial estimation of hydrate formation temperature （HFT） under the circumstances of indeterminate gas *** far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and *** main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity *** reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.

关键词： natural gas hydrates hydrate formation temperature gas gravity method empirical correlation

Effective Controlled Islanding Method for Power Grids Solving a Sequence of Optimization Problems

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CSEE Journal of Power and Energy Systems 2022年第4期8卷 1004-1012页

作者： mahdi Amini Haidar Samet Ali Reza Seifi mahdi Davarpanah School of Electrical and Computer Engineering Shiraz UniversityShirazIran Department of Electrical Engineering Eindhoven University of TechnologyEindhoventhe Netherlands the Electrical and Computer Engineering School College of EngineeringUniversity of TehranTehranIran

Controlled islanding is an important approach to prevent instability in power *** this paper,a novel approach is proposed for power system separation,which consists of two steps:1)Finding multiple islanding scenarios;2)Choosing the best option to obtain the most desirable *** the first step,different islanding solutions are determined by a proposed hierarchical clustering *** this algorithm,which is based on a minimum active power flow disruption objective function,the generator coherency constraints are considered in the clustering *** the second step,the best separation scenario is chosen based on an arbitrary objective ***,in this paper,the amount of load shedding and the voltage profile deviation after separation are considered as the final criteria to select the best solution among available *** so doing,the degree of load importance is also taken into *** proposed two-step method is applied on an IEEE 9-bus test system and it is also evaluated on an IEEE 39-bus *** simulation results on the IEEE 39-bus grid and the comparative analysis with a state-of-the-art method confirm that the final islanding solution is more optimized based on the secondary criteria,which have not been addressed in the existing ***,the proposed method is computationally efficient and can be employed in real-scale power grids.

关键词： Graph theory hierarchical spectral clustering power system separation power system instability two-step approach.

Vanadium oxide nanotubes for selective catalytic reduction of NO_x with NH_3

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Chinese Journal of Chemical Engineering 2016年第7期24卷 914-919页

作者： Seyed mahdi Mousavi Faculty of Chemistry University of Kashan

Vanadium oxide （VOx） nanostructures, synthesized by hydrothermal treatment using dodecylamine as template, were evaluated for the selective catalytic reduction of NOx with ammonia （NH3-SCR）, The effect of solvent type in the reaction mixture （EtOH/（EtOH ＋ H20）） and time of hydrolysis was studied. The obtained materials were characterized by XRD, SEM, TEM and BET, The VOx nanorods （80-120 nm diameter and 1-4 μm length） were synthesized in 25 vol% EtOH/（EtOH ＋ H20） and the open-ended multiwalled VOx nanotube （50-100 nm inner diameter, 110-180 nm outer diameter and 0,5-2 pm length） synthesized in 50 vol% EtOH/（EtOH ＋ H20）. VOx nanotuhes performed the superior NH3-SCR activity under a gas hourly space velocity of 12,000 h-1 at low temperature of 250 ~C （NOx conversion of 893g ＆ N2 selectivity of 100%）, while most of the developed Vanadia base catalysts are active at high temperature （〉350 ℃）. The superior NH3-SCR activity ofVOx nanotubes at low tem- perature is related to nanocrystalline structure, special nanotube morphology as well as high specific surface area.

关键词： Hydrothermal Nanotubes NOx Pollution SCR

Uncertainty propagation in dynamics of composite plates: A semi-analytical non-sampling-based approach

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1359-1371页

作者： mahdi FAKOOR Hadi PARVIZ Faculty of New Sciences and Technologies University o f TehranTehran 14395-1561Iran

In this study,the influences of spatially varying stochastic properties on free vibration analysis of composite plates were investigated via development of a new approach named the deterministic-stochastic Galerkin-based semi-analytical *** material properties including tensile modulus,shear modulus,and density of the plate were assumed to be spatially varying and *** fields with first-order Markov kernels were utilized to define the aforementioned material *** stochastic fields were decomposed via application of the K arhunen-Loeve theorem.A first-order shear deformation theory was assumed,following which the displacement field was defined using admissible trigonometric modes to derive the potential and kinetic *** stochastic equations of motion of the plate were obtained using the variational *** deterministic-stochastic Galerkin-based method was utilized to find the probability space of natural frequencies,and the corresponding mode shapes of the plate were determined using a polynomial chaos *** proposed method significantly reduced the size of the mathematical models of the structure,which is very useful for enhancing the computational efficiency of stochastic *** methodology was verifed using a stochastic finite element method and the available results in *** sensitivity of natural frequencies and corresponding mode shapes due to the uncertainty of material properties was investigated,and the results indicated that the higher-order modes are more sensitive to uncertainty propagation in spatially varying properties.

关键词： composite plate spatially varying stochastic properties Galerkin method polynomial chaos approach semi-analytical approach

Shear wall layout optimization of tall buildings using Quantum Charged System Search

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Frontiers of Structural and Civil Engineering 2020年第5期14卷 1131-1151页

作者： Siamak TALATAHARI mahdi RABIEI Department of Civil Engineering University of TabrizTabriz ***Iran Engineering Faculty Near East UniversityNicosia 99138Turkey

This paper presents a developed meta-heuristic algorithm to optimize the shear walls of tall reinforced concrete *** types of walls are considered as lateral resistant *** this paper,Quantum Charged System Search(QCSS)algorithm is presented as a new optimization method and used to improve the convergence capability of the original Charged System *** cost of tall building is taken as the objective *** the design of the lateral system plays a major role in the performance of the tall buildings,this paper proposes a unique computational technique that,unlike available works,focuses on structural efficiency or architectural *** technique considers both structural and architectural requirements such as minimum structural costs,torsional effects,flexural and shear resistance,lateral deflection,openings and *** robustness of the new algorithm is demonstrated by comparing the outcomes of the QCSS with those of its standard algorithm.

关键词： Quantum Charged System Search shear wall layout optimization tall buildings