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Data driven models for compressive strength prediction of concrete at high temperatures

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Frontiers of Structural and Civil Engineering 2020年第2期14卷 311-321页

作者： Mahmood AKBARI vahid JAFARI DELIGANI Department of Civil Engineering Faculty of EngineeringUniversity of KashanKashan ***Iran

The use of data driven models has been shown to be useful for simulating complex engineering processes,when the only information available consists of the data of the *** this study,four data-driven models,namely multiple linear regression,artificial neural network,adaptive neural fuzzy inference system,and K nearest neighbor models based on collection of 207 laboratory tests,are investigated for compressive strength prediction of concrete at high *** addition for each model,two different sets of input variables are examined:a complete set and a parsimonious set of involved *** results obtained are compared with each other and also to the equations of NIST Technical Note standard and demonstrate the suitability of using the data driven models to predict the compressive strength at high *** addition,the results show employing the parsimonious set of input variables is sufficient for the data driven models to make satisfactory results.

关键词： data driven model compressive strength oncrete high temperature

Mechanical Properties and Microstructure Evolution of AA1100 Aluminum Sheet Processed by Accumulative Press Bonding Process

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Acta Metallurgica Sinica(English Letters) 2016年第8期29卷 735-741页

作者： Amir Mostafapor vahid Mohammadinia Department of Mechanical Engineering University of Tabriz Department of Mechanical Engineering University of Maragheh

Accumulative press bonding（APB） is a novel variant of severe plastic deformation processes,which is devised to produce materials with ultra-fine *** the present work,the mechanical properties and microstructural evolution of AA1100 alloy,which is produced by APB technique,were *** study of the microstructure of AA1100 alloy was performed by optical *** results revealed that the grain size of the samples decreased to 950 nm after six passes of APB *** yield strength of AA1100 alloy after six passes of the process increased up to 264 MPa,which is three times higher than that of the as-cast material（89 MPa）.After six passes,microhardness values of AA1100 alloy increased from 38 to 61 ***,the results showed that the behavior of variations in mechanical properties is in accordance with the microstructural changes and it can be justified by using the Hall-Patch ***,the rise in the yield strength can be attributed to the reduction in the grain size leading to the strain hardening.

关键词： Severe plastic deformation Accumulative press bonding Mechanical properties Metallurgical properties AA1100 alloy

3D object retrieval based on histogram of local orientation using one-shot score support vector machine

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Frontiers of Computer Science 2015年第6期9卷 990-1005页

作者： vahid MEHRDAD Hossein EBRAHIMNEZHAD Computer Vision Research Laboratory Electrical Engineering Faculty Sahand University of Technology Tabriz *** Iran

In this paper, a content based descriptor is pro- posed to retrieve 3D models, which employs histogram of local orientation （HLO） as a geometric property of the shape. The proposed 3D model descriptor scheme consists of three steps. In the first step, Poisson equation is utilized to define a 3D model signature. Next, the local orientation is calculated for each voxel of the model using Hessian matrix. As the final step, a histogram-based 3D model descriptor is extracted by accumulating the values of the local orientation in bins. Due to efficiency of Poisson equation in describing the models with various structures, the proposed descriptor is capable of discriminating these models accurately. Since, the inner vox- els have a dominant contribution in the formation of the de- scriptor, sufficient robustness against noise can be achieved. This is because the noise mostly influences the boundary vox- els. Furthermore, we improve the retrieval performance us- ing support vector machine based one-shot score （SVM-OSS） similarity measure, which is more efficient than the conven- tional methods to compute the distance of feature vectors. The rotation normalization is performed employing the prin- cipal component analysis. To demonstrate the applicability of HLO, we implement experimental evaluations of precision- recall curve on ESB, PSB and WM-SHREC databases of 3D models. Experimental results validate the effectiveness of the proposed descriptor compared to some current methods.

关键词： 3D model retrieval histogram of local orientation visual based shape descriptor poisson equation

Protein adsorption, cell viability and corrosion properties of Ti6Al4V alloy treated by plasma oxidation and anodic oxidation

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1269-1280页

作者： ÖzgüBayrak Hojjat Ghahramanzadeh asl Ayşe Ak Department of Mechanical Engineering Erzincan Binali Yıldırım UniversityErzincan 24100Turkey Department of Mechanical Engineering Karadeniz Technical UniversityTrabzon 61080Turkey Vocational School of Health Services Medical Imaging Techniques ProgrammeKocaeli UniversityKocaeli 41001Turkey

The hardness,wettability,and electrochemical properties of Ti6Al4V alloy surfaces treated with anodic oxidation and plasma oxidation as well as the viabilities of the different cell lines on the obtained surfaces were *** anodic oxidation was performed for 10 min under 100 V potential,and it resulted in a 0.95μm thick nanoporous anatase-TiO2 *** the other hand,plasma oxidation was carried out at 650℃ for 1 h and resulted in a dense rutile-TiO2 structure with a thickness of 1.2μ*** a hardness of HV0.025823 and roughness of^220 nm were obtained by plasma oxidation,those obtained by anodic oxidation were HV0.025512 and^130 nm,*** anodic oxidation process created a more hydrophilic surface with a contact angle of 87.2°.Both oxidation processes produced similar properties in terms of corrosion behavior and showed better resistance than the as-received state in a certain range of ***,the surface treatments led to no significant change in the protein adsorption levels,which indicates that the difference in viability between the osteoblast and fibroblast cells was not due to the difference in surface protein *** all the factors,the surfaces obtained by anodic oxidation treatment revealed higher cell viability than those obtained by plasma oxidation(p=0.05).

关键词： Ti6Al4V oxidation corrosion cell viability protein adsorption

Operation and Flexibility Contribution of Natural Gas Tanks in Multi-carrier Energy Systems

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CSEE Journal of Power and Energy Systems 2021年第3期7卷 622-631页

作者： Alireza Hamedi Ali Reza Seifi Dariush Keihan asl School of Electrical and Computer Engineering Shiraz UniversityShirazIran

Energy storage systems(ESSs)have an assistive role in the operation of multi-carrier energy *** paper presents a type of natural gas(NG)ESS called NG tank and studies the operation and flexibility contributions of this ESS in the *** tank modeling and formulation are unified the same as the electrical *** NG tank and the electrical ESS models are implemented on a large-scale multi-carrier energy network and the impressive effects of utilizing these units are investigated in the operational planning of the energy *** optimal operational problem is solved utilizing the teaching learning based optimization(TLBO)algorithm to minimize the operational cost of the system.

关键词： Electrical ESS multi-carrier energy system NG tank optimal operation

Simplified modeling of frequency behavior in photonic crystal vertical cavity surface emitting laser with tunnel injection quantum dot in active region

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Chinese Physics B 2017年第2期26卷 260-267页

作者： Mehdi Riahinasab vahid Ahmadi Elham Darabi Department of Electrical Engineering Science and Research Branch Islamic Azad University Tehran Iran Department of Electrical Engineering Tarbiat Modares University Tehran Iran Plasma Physics Research Center Science and Research Branch Islamic Azad University Tehran Iran

In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers（Ph C-TIQD-VCSEL） are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer（WL） and at excited state（ES） levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-d B bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.

关键词： modulation transfer function photonic crystal(PhC) tunnel injection quantum dot(TIQD) vertical cavity surface emitting laser(VCSEL)

Enhancement of CO_2 adsorption on nanoporous chromium terephthalate(MIL-101) by amine modification

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Journal of Natural Gas Chemistry 2012年第3期21卷 339-343页

作者： Mansoor Anbia vahid Hoseini Research Laboratory of Nanoporous Materials Faculty of ChemistryIran University of Science and TechnologyFarjam StreetNarmakTehran 16846Iran

Carbon dioxide （CO2） adsorption on a standard metal-organic framework MIL-101 and a pentaethylenehexamine modified MIL-101 （PEHA- MIL-101） are investigated and compared in this study. The adsorbent samples were characterized by XRD, FT-IR and nitrogen adsorption- desorption isotherms analysis. CO2 adsorption capacity was measured by a volumetric method. MIL-101 and PEHA-MIL-101 exhibited CO2 adsorption capacities of 0.85 and 1.3 mmO1CO2/gadsorbent at 10 bar and 298 K, respectively. It is observed that CO2 adsorption capacity was fairly improved about 50% after amine modification.

关键词： CO2 adsorption metal-organic framework MIL-101 amine modification pentaethylenehexamine (PEHA)

Elastic Properties of Potassium Halides under Pressure

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Journal of Materials Science & Technology 2008年第2期24卷 241-244页

作者： K.haddadi L.Louail D.Maouche Department of Physics Faculty of SciencesUniversity of SetifAlgeria

The moderate-pressure elastic properties of potassium halides KX （X=F, Cl, Br） was studied theoretically using the density functional theory （DFT） with normconserving pseudopotentials method. The phase transformation from the B1 phase （NaCl-type structure） to the denser B2 phase （CsCl-type structure） occurred at 7.7, 3.46 and 2.96 GPa for KF, KCI and KBr, respectively. The elastic stiffness coefficients and bulk modulus of these materials were calculated as function of hydrostatic pressure and compared with both the experimental and theoretical values.

关键词： Phase transitions Elastic coefficients Solid alkali halides

On Time-Constant Robust Tuning of Fractional Order [Proportional Derivative] Controllers

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IEEE/CAA Journal of Automatica Sinica 2019年第5期6卷 1179-1186页

作者： vahid Badri Mohammad Saleh Tavazoei Electrical Engineering Department Sharif University of TechnologyTehranIran

This paper deals with analyzing a newly introduced method for tuning of fractional order [proportional derivative](FO[PD]) controllers to be used in motion control. By using this tuning method, not only the phase margin and gain crossover frequency are adjustable, but also robustness to variations in the plant time-constant is guaranteed. Conditions on the values of control specifications(desired phase margin and gain crossover frequency) for solution existence in this tuning method are found. Also, the number of solutions is analytically determined in this study. Moreover, experimental verifications are presented to indicate the applicability of the obtained results.

关键词： Fractional order controller robustness solution existence tuning method