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Acta Metallurgica Sinica(English Letters) 2014年第6期27卷 1144-1151页

作者： Abdollah Hajalilou Mansor Hashim Halimah Mohamed kamari kazem javadi Samikannu Kanagesan Mohammad Parastegari Materials Synthesis and Characterization Laboratory Institute of Advanced Technology (ITMA) University Putra Malaysia Physics Department University Putra Malaysia Irankhodrow Industry Mechanical Testing Laboratory Materials Synthesis and Characterization Laboratory Isfahan University of Technology

ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion temperature as well as the formation route for synthesizing ZrC powder particles were studied. The samples were characterized by XRD, SEM, TEM, and DTA. The XRD results revealed that, after 18 h of mechanical activation, ZrO2/ZC/Mg/Fe reacted with the self-propagating combustion（SHS） mode at 870 °C producing the ZrC–Fe nanocomposite. It was also found that both mechanical activation and Fe content played key roles in the ZrC synthesis temperature. With a Fe content of（5–40） wt%, the SHS reaction proceeded favorably and both the ZrC formation temperature and the adiabatic temperature（Tad） decreased. The Mg O content was removed from the final products using a leaching test process by dissolving in hydrochloric and acetic acids.

关键词： Mechanical activation(MA) Combustion synthesis Fe–ZrC composite Leaching process

Effect of CO_(2)exposure on the mechanical strength of geopolymerstabilized sandy soils

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 670-681页

作者： Hamid Reza Razeghi Armin Geranghadr Fatemeh Safaee Pooria Ghadir Akbar A.javadi School of Civil Engineering Iran University of Science and TechnologyTehran***Iran Department of Engineering University of ExeterExeterEX44QFUK

In recent years,there has been growing interest in developing methods for mitigating greenhouse effect,as greenhouse gas emissions continue to contribute to global temperature *** the other hand,investigating geopolymers as environmentally friendly binders to mitigate the greenhouse effect using soil stabilization has been widely ***,the effect of CO_(2)exposure on the mechanical properties of geopolymer-stabilized soils is rarely *** this context,the effect of CO_(2)exposure on the mechanical and microstructural features of sandy soil stabilized with volcanic ash-based geopolymer was *** factors were concerned,for example the binder content,relative density,CO_(2)pressure,curing condition,curing time,and carbonate *** results showed that the compressive strength of the stabilized sandy soil specimens with 20%volcanic ash increased from 3 MPa to 11 *** was also observed that 100 kPa CO_(2)pressure was the optimal pressure for strength development among the other *** mechanical strength showed a direct relationship with binder content and carbonate ***,in the ambient curing(AC)condition,the mechanical strength and carbonate content increased with the curing ***,the required water for carbonation evaporated after 7 d of oven curing(OC)condition and as a result,the 14-d cured samples showed lower mechanical strength and carbonate content in comparison with 7-d cured ***,the rate of strength development was higher in OC cured samples than AC cured samples until 7 d due to higher geopolymerization and carbonation rate.

关键词： Soil stabilization CO_(2)effect Geopolymer

Strength properties of xanthan gum and guar gum treated kaolin at different water contents

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 1160-1172页

作者： Irem Bozyigit Akbar javadi Selim Altun Department of Civil Engineering Ege UniversityBornova-IzmirTurkey College of Engineering Mathematics and Physical SciencesUniversity of ExeterExeterUK

Nowadays,using biopolymer as a ground improvement method has become very ***,since biopolymers are organic and degradable,their long-term effect is not fully *** this study,the effects of biopolymers on the mechanical behavior of kaolin clay were investigated through a comprehensive program of *** types of biopolymer,*** gum and guar gum were chosen to investigate the effect of biopolymer *** this purpose,specimens were prepared using standard Proctor energy at four different water contents(25%,30%35%and 40%)with 0.5%,1%,1.5%and 2%biopolymer *** specimens were cured for 1 d,7 d,28 d and 90 ***,some of the specimens were kept in the curing room for 3 years to observe the long-term effect of the *** the end of the curing periods,the specimens were subjected to unconfined compression test,and scanning electron microscopy(SEM)analysis was performed to observe the mechanism of strength *** results revealed that the unconfined compressive strength(UCS)of the specimens treated with biopolymers increased in all biopolymer inclusion levels and water contents up to a 90-d curing *** specimens containing xanthan gum,the maximum strength increase was observed at 25%water content and 2%xanthan gum with 90-d *** strength increased 5.23 times induced by xanthan gum addition when compared to the pure ***,the increase in strength reached 8.53 times in specimens treated with guar ***,increasing water content caused more ductile behavior,thus increasing the axial deformation.

关键词： Biopolymer Clay Unconfined compressive strength(UCS) Xanthan gum Guar gum Strength properties

Plasma Sprayed NiAl Intermetallic Coating Produced with Mechanically Alloyed Powder

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Journal of Materials Science & Technology 2011年第9期27卷 816-820页

作者： Mehrshad Moshref javadi Hossein Edris Mahdi Salehi Marine Engineering Department Maleke-Ashtar University of Technology Department of Materials Engineering Isfahan University of Technology

In the present research, mechanically alloyed Ni-AI powder was utilized to develop plasma sprayed coatings, and the effect of the spray distance and heat treatment on the phases, microstructure, and hardness of the coat- ings were examined. Coatings were analyzed by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy-dispersive spectroscopy （EDS） and through microhardness measurements. Although mechanically alloyed Ni-AI powder showed no intermetallic phases, the coatings did. Different spray distances from 5 to 19 cm were employed for plasma spray and the specimens were heat treated at different temperatures, then the amount of oxides, porosity and hardness of the coatings were changed according to the spray condition. The thermal energy of the plasma spray caused the formation of NiAI phases while particles flew to the substrate or after that. Extreme increase in heat treatment temperature and spray distance resulted in oxidation and reduction in the quality of the coating. Furthermore, the best spray distance and heat treatment temperature to gain the NiAI intermetallic coating were established.

关键词： Coating materials Intermetallics Phase transformation Plasma spray

A preliminary study of impact of reduced system inertia in a low-carbon power system

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Journal of Modern Power Systems and Clean Energy 2015年第1期3卷 82-92页

作者： Di WU Milad javadi John Ning JIANG Electricity and Energy Reliability and Risk Laboratory School of Electrical and Computer EngineeringUniversity of OklahomaNormanOKUSA

One of the important features of low-carbon electric power system is the massive deployment of renewable energy resources in the advent of a new carbon-strained *** generation is a major technology of generating electric power with zero carbon dioxide *** a power system with the high penetration of wind generation,the displacement of conventional synchronous generators with variable speed wind turbines reduces system *** leads to larger system frequency deviation following a loss of large *** this paper,the impact of the reduction of system inertia on system frequency is analyzed as the result of the integration of a significant amount of wind generation into power ***,we present a preliminary study of the impact of the distribution of the inertia contributions from those online conventional synchronous generators on the rate of change of frequency(ROCOF)based on the total energy injected into the system due to the *** total fault energy is represented using Hamiltonian *** the IEEE 39-bus system,it is shown that for a fault with the given injected total energy,clearing time,and location,the distribution of inertia contributions can significantly affect the magnitude of ***,for such a fault with different locations,the average of the magnitudes of ROCOF caused by the fault at different locations is larger when the distribution of the inertia contributions is more dispersed.

关键词： Carbon dioxide emission Wind generation System inertia Rate of change of frequency

Self-centring segmental retaining walls—A new construction system for retaining walls

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Frontiers of Structural and Civil Engineering 2021年第4期15卷 980-1000页

作者： Mehdi javadi Reza HASSANLI Md Mizanur RAHMAN Md Rajibul KARIM UniSA STEM University of South AustraliaMawson Lakes5095Australia

This paper reports on an experimental study on a new self-centring retaining wall *** post-tensioned segmental retaining walls(PSRWs)were experimentally *** of the walls was constructed using seven T-shaped concrete segments with a dry *** walls were tested under incrementally increasing cyclic lateral *** effect of the wall height,levels of post-tensioning(PT)force,and bonded versus unbonded condition of PT reinforcement on the structural behavior of the PSRWs was *** results showed that such PSRWs are structurally adequate for water retaining *** to the results,increasing the wall height decreases initial strength but increases the deformation capacity of the *** larger deformation capacity and ductility of PSRW make it a suitable structural system for fluctuating loads or deformation,e.g.,*** was also found that increasing the PT force increases the wall’s stiffness;however,reduces its *** residual drift and the extent of damage of the unbonded PSRWs were significantly smaller than those of the bonded *** suggest that this newly developed self-centring retaining wall can be a suitable structural system to retain lateral *** to its unique deformation capacity and self-centring behavior,it can potentially be used for seawall application.

关键词： retaining wall segmental precast concrete unbonded post-tensioning water retaining wall seawall

A Novel Probabilistic Hybrid Model to Detect Anomaly in Smart Homes

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Computer Modeling in Engineering & Sciences 2019年第12期121卷 815-834页

作者： Sasan Saqaeeyan Hamid Haj Seyyed javadi Hossein Amirkhani Department of Computer Engineering Borujerd BranchIslamic Azad UniversityBorujerdIran Department of Mathematics and Computer Science Shahed UniversityTehranIran Computer Engineering and Information Technology Department University of QomQomIran

Anomaly detection in smart homes provides support to enhance the health and safety of people who live *** to the previous studies done on this topic,less attention has been given to hybrid *** paper presents a two-steps hybrid probabilistic anomaly detection model in the smart ***,it employs various algorithms with different characteristics to detect anomalies from sensory ***,it aggregates their results using a Bayesian *** this Bayesian network,abnormal events are detected through calculating the probability of abnormality given anomaly detection results of base *** evaluation of a real dataset indicates the effectiveness of the proposed method by reducing false positives and increasing true positives.

关键词： Smart homes sensory data anomaly detection Bayesian networks ensemble method

APPROXIMATION OF ADJOINT OF A MULTIPLIER ON BANACH ALGEBRAS

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Acta Mathematica Scientia 2012年第2期32卷 783-792页

作者： A.Ghaffari S.javadi H.Khodaei Department of Mathematics Semnan UniversityP.O.Box 35195-363SemnanIran

For a Banach algebra A, we denote by .A＊ and .A＊＊ the first and the second duals of A respectively. Let T be a mapping from .A＊ to itself. In this article, we will investigate some stability results concerning the equations T（αf ＋ βg） -= αT（f）＋ βT（g）, T（af） = aT（f） andT（αf ＋βg）＋ T（αf - βg） =- 2α2T（f）＋ 2β2T（g） where f, g e .A＊, a ∈ A, and α,β ∈ Q ／ {0}.

关键词： Additive and quadratic mappings Arens products Banach algebra multi-plier stability

Behaviour of self-centring shear walls——A state of the art review

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Frontiers of Structural and Civil Engineering 2023年第1期17卷 53-77页

作者： Mehdi javadi Reza HASSANLI Md Mizanur RAHMAN Md Rajibul KARIM UniSA STEM University of South AustraliaAdelaide 5095Australia

The application of unbonded post-tensioning (PT) in structural walls has led to the development of advanced self-centring (rocking) shear wall systems that has significant advantages, including accelerated construction due to the incorporation of prefabricated elements and segmental construction for different materials (e.g., concrete, masonry, and timber), reduced residual drifts, and little damage upon extreme seismic and wind loads. Concrete, masonry, and timber are often used for the construction of unbonded PT structural wall systems. Despite extensive research since the 1980s, there are no well-established design guidelines available on the shear wall configuration with the required energy dissipation system, joint’s locations and acceptance criteria for shear sliding, confinement, seismic performance factors, PT loss, PT force range and residual drifts of shear walls subjected to lateral loads. In this research a comprehensive state-of-the-art literature review was performed on self-centring shear wall system. An extensive study was carried out to collect a database of 100 concrete, masonry, and self-centring shear wall tests from the literature. The established database was then used to review shear walls’ configurations, material, and components to benchmark requirements applicable for design purposes. The behaviour of concrete, masonry and timber shear walls were compared and critically analysed. The general behaviour, force-displacement performance of the walls, ductility, and seismic response factors, were critically reviewed and analysed for different self-centring wall systems to understand the effect of different parameters including configurations of the walls, material used for construction of the wall (concrete, masonry, timber) and axial stress ratio. The outcome of this research can be used to better understand the behaviour of self-centring wall system in order to develop design guidelines for such walls.

关键词： self-centring shear walls rocking walls energy dissipation seismic performance factors PT loss residual drift

A novel algorithm for frequency dependent modeling of ferrite ring and its optimum design to study VFTO behaviors within GIS

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Frontiers in Energy 2014年第1期8卷 90-100页

作者： Mehrdad MAJIDI Hamid javadi Moein MANBACHI Department of Electrical & Computer Engineering Power & WaterUniversity of Technology Tehran Iran School of Engineering Science Simon Fraser University 8888 University Drive Burnaby British Columbia Canada

One of the fundamental issues in gas insulated substations （GIS） which has destructive effects on GIS equipment is the very fast transient over-voltages （VFTOs）. This paper models a 400/230 kV substation in order to study the effects of VFTO extensively implemen- ted on EMTP-RV. In addition, the application of ferrite rings for suppressing VFTOs is assessed thoroughly. The main advantage of this paper is its new proposed algorithm according to the ferrite ring frequency dependent modeling that is validated with experimental results. This paper examines the effects of three compositions of the ferrite ring on VFTO suppression. Moreover, it estimates the dimension of the ferrite ring based on the SF6 gas insulation withstand and the maximum effect of ferrite rings on VFTO suppression constraint with the COMSOL multiphysics software. Furthermore, it gains VFTO attenuated percentages due to the installation of the ferrite ring in different GIS nodes. Finally, it analyzes the offered VFTO amendment technique in various GIS switching scenarios.

关键词： comsol multiphysics EMTP-RV ferrite ring,gas insulated substations (GIS) transient over-voltage,insulation coordination