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Performance-based seismic assessment of a historical masonry arch bridge:Effect of pulse-like excitations

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Frontiers of Structural and Civil Engineering 2023年第6期17卷 855-869页

作者： Amirhosein SHABANI mahdi KIOUMARSI Vagelis PLEVRIS Department of Built Environment Oslo Metropolitan UniversityOslo 0166Norway Department of Civil and Architectural Engineering Qatar UniversityDoha 2713Qatar

Seismic analysis of historical masonry bridges is important for authorities in all countries hosting such cultural heritage *** masonry arch bridge investigated in this study was built during the Roman period and is on the island of Rhodes,in *** seismic records were considered and categorized as far-field,pulse-like nearfield,and non-pulse-like *** earthquake excitations were scaled to a target spectrum,and nonlinear timehistory analyses were performed in the transverse *** performance levels were introduced based on the pushover curve,and the post-earthquake damage state of the bridge was *** to the results,pulse-like near-field events are more damaging than non-pulse-like near-field ground *** the bridge is more vulnerable to far-field excitations than near-field ***,the structure will suffer extensive post-earthquake damage and must be retrofitted.

关键词： masonry arch bridges seismic behavior modal properties pulse-like records nonlinear time history analysis

On Zero Dynamics and Controllable Cyber-Attacks in Cyber-Physical Systems and Dynamic Coding Schemes as Their Countermeasures

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IEEE/CAA Journal of Automatica Sinica 2024年第11期11卷 2191-2203页

作者： mahdi Taheri Khashayar Khorasani Nader Meskin the Department of Electrical and Computer Engineering Concordia University the Department of Electrical Engineering Qatar University

In this paper, we study stealthy cyber-attacks on actuators of cyber-physical systems(CPS), namely zero dynamics and controllable attacks. In particular, under certain assumptions, we investigate and propose conditions under which one can execute zero dynamics and controllable attacks in the CPS. The above conditions are derived based on the Markov parameters of the CPS and elements of the system observability matrix. Consequently, in addition to outlining the number of required actuators to be attacked, these conditions provide one with the minimum system knowledge needed to perform zero dynamics and controllable cyber-attacks. As a countermeasure against the above stealthy cyber-attacks, we develop a dynamic coding scheme that increases the minimum number of the CPS required actuators to carry out zero dynamics and controllable cyber-attacks to its maximum possible value. It is shown that if at least one secure input channel exists, the proposed dynamic coding scheme can prevent adversaries from executing the zero dynamics and controllable attacks even if they have complete knowledge of the coding system. Finally, two illustrative numerical case studies are provided to demonstrate the effectiveness and capabilities of our derived conditions and proposed methodologies.

关键词： Controllable attacks cyber-physical systems(CPS) dynamic coding zero dynamics attacks stealthy cyber-attacks

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Estimating trends of the Mediterranean Sea level changes from tide gauge and satellite altimetry data (1993-2015)

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Journal of Oceanology and Limnology 2019年第4期37卷 1176-1185页

作者： TAIBI Hebib HADDAD mahdi Centre of Space Techniques(CTS)

The impact of climate change on sea level has received a great deal of attention by scientists worldwide. In this context, the problem of sea levels on global and regional scales have been analyzed in a number of studies based on tide gauges observations and satellite altimetry measurements. This study focuses on trend estimates from 18 high-quality tide gauge stations along the Mediterranean Sea coast. The seasonal Mann-Kendall test was run at a 5% significance level for each of the 18 stations for the period of 1993-2015 (satellite altimetry era). The results of this test indicate that the trends for 17 stations were statistically significant and showed an increase (no significant trend was observed only at one station). The rates of sea level change for the 17 stations that exhibit significant trends, estimated using seasonal Sen's approach, range after correction for Vertical Land Motion (VLM) from 1.48 to 8.72 mm/a for the period 1993-2015. Furthermore, the magnitude of change at the location of each tide gauge station was estimated using the satellite altimetry measurements. Thus, the results obtained agree with those from the tide-gauge data analysis.

关键词： sea level tidal height satellite altimetry trend analysis Mann-Kendall test Sen's slope estimates

Nuclear data for the cyclotron production of ^(117)Sb and ^(90)Nb

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Chinese Physics C 2011年第3期35卷 248-254页

作者： Enferadi Milad Sadeghi mahdi Islamic Azad University Science and Research Branch Agricultural Medical and Industrial Research SchoolNuclear Science and Technology Research Institute

This presented study is to make comparison of cross sections to produce 117Sb and 90Nb via different reactions with particle incident energy up to 70 MeV as a part of systematic studies on particle-induced activations on enriched Sn, Y2O3 and ZrO2 targets, theoretical calculation of production yield, calculation of required thickness of target and suggestion of optimum reaction to produce Antimony-117 and Niobium-90.

关键词： 117Sb 90Nb excitation functions TALYS-1.2 ALICE/ASH

Electron acceleration in the inverse free electron laser with a helical wiggler by axial magnetic field and ion-channel guiding

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Chinese Physics C 2012年第9期36卷 879-885页

作者： Reza Khazaeinezhad mahdi Esmaeilzadeh Department of Physics Iran University of Science and TechnologyTehranIran

Electron acceleration in the inverse free electron laser （IFEL） with a helical wiggler in the presence of ion-channel guiding and axial magnetic field is investigated in this article. The effects of tapering wiggler amplitude and axial magnetic field are calculated for the electron acceleration. In free electron lasers, electron beams lose energy through radiation while in IFEL electron beams gain energy from the laser. The equation of electron motion and the equation of energy exchange between a single electron and electromagnetic waves are derived and then solved numerically using the fourth order Runge-Kutta method. The tapering effects of a wiggler magnetic field on electron acceleration are investigated and the results show that the electron acceleration increases in the case of a tapered wiggler magnetic field with a proper taper constant.

关键词： IFEL helical wiggler ion-channel guiding axial magnetic field tapering effects

Optimal monitoring and attack detection of networks modeled by Bayesian attack graphs

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Cybersecurity 2024年第1期7卷 1-15页

作者： Armita Kazeminajafabadi mahdi Imani Department of Electrical and Computer Engineering Northeastern UniversityBostonMAUSA

Early attack detection is essential to ensure the security of complex networks,especially those in critical *** is particularly crucial in networks with multi-stage attacks,where multiple nodes are connected to external sources,through which attacks could enter and quickly spread to other network *** attack graphs(BAGs)are powerful models for security risk assessment and mitigation in complex networks,which provide the probabilistic model of attackers’behavior and attack progression in the *** attack detection techniques developed for BAGs rely on the assumption that network compromises will be detected through routine monitoring,which is unrealistic given the ever-growing complexity of *** paper derives the optimal minimum mean square error(MMSE)attack detection and monitoring policy for the most general form of *** exploiting the structure of BAGs and their partial and imperfect monitoring capacity,the proposed detection policy achieves the MMSE optimality possible only for linear-Gaussian state space models using Kalman *** adaptive resource monitoring policy is also introduced for monitoring nodes if the expected predictive error exceeds a user-defined *** and efficient matrix-form computations of the proposed policies are provided,and their high performance is demonstrated in terms of the accuracy of attack detection and the most efficient use of available resources using synthetic Bayesian attack graphs with different topologies.

关键词： Multi-stage attacks Bayesian attack graph Attack detection Optimal monitoring

Thermodynamical and catalytic aspects of zinc separation from aqueous solution

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Chinese Journal of Chemical Engineering 2018年第12期26卷 2455-2460页

作者： Sajjad Aghazadeh mahdi Gharabaghi Ziaedin Shafaei School of Mining Engineering College of Engineering University of Tehran

The present research work examines extraction mechanism of zinc by D2 EHPA(Di-2-ethyl hexyl phosphoric acid) and comprehensively studies the main effective parameters on the process. Results of thermodynamic experiments showed that zinc extraction by D2 EHPA was endothermic and spontaneous, and thermodynamic parameters including entropy and enthalpy were + 27.37 J·mol^(-1)·K^(-1) and 25.21 kJ·mol^(-1), *** free energy was varied between-7.21 kJ·mol^(-1) and-8.41 kJ·mol^(-1) with the variation of temperature from 20 °C to 70 °C. Solution ionic strength was increased by addition of potassium and lithium sulfate solution while addition of calcium sulfate decreased ionic strength whereby zinc extraction efficiency was also *** showed positive synergism at concentration of 5%(v/v) and negative synergism effect at concentrations of2% and 10%. Simultaneous addition of both TBP and salt caused extraction efficiency to drop significantly and lower both TBP and ionic strength efficiency. Results showed that a continuous addition of TBP tends to effectively improve the zinc extraction efficiency. Experiments in the presence of catalyst Ni-Raney demonstrated that zinc extraction kinetic increases remarkably and due to easy recycling of the catalyst, we can propose a novel idea in solvent extraction field.

关键词： Catalyst Ni-Raney D2EHPA Ionic strength Separation Solvent extraction Thermodynamic

Assessment of liquefaction potential based on shear wave velocity:Strain energy approach

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3733-3745页

作者： Mohammad Hassan Baziar mahdi Alibolandi School of Civil Engineering Iran University of Science and TechnologyTehran16846-13114Iran

Liquefaction assessment based on strain energy is significantly superior to conventional stress-based *** main purpose of the present study is to investigate the correlation between shear wave velocity and strain energy capacity of silty *** dissipated energy until liquefaction occurs was calculated by analyzing the results of three series of comprehensive cyclic direct simple shear and triaxial tests on Ottawa F65,Nevada,and Firoozkuh sands with varying silt content by weight and relative ***,the shear wave velocity of each series was obtained using bender element or resonant column ***,for the first time,a liquefaction triggering criterion,relating to effective overburden normalized liquefaction capacity energy(WL=s’c)to effective overburden stresscorrected shear wave velocity(eVs1)has been *** accuracy of the proposed criteria was evaluated using in situ *** results confirm the ability of shear wave velocity as a distinguishing parameter for separating liquefied and non-liquefied soils when it is calculated against liquefaction capacity energy(WL=s’c).However,the proposed WL=s’c-Vs1 curve,similar to previously proposed cyclic resistance ratio(CRR)-Vs1 relationships,should be used conservatively for fields vulnerable to liquefaction-induced lateral spreading.

关键词： Liquefaction Strain energy capacity Shear wave velocity Cyclic triaxial test Cyclic direct simple shear test Resonant column test Bender element test

NAPHTHALIMIDE BASED DISPERSE DYES FOR NYLON 6 AND POLYESTER(PET) FIBERS:SYNTHESIS AND EVALUATION OF TECHNICAL PROPERTIES IN THE PRESENCE OF UREA

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Chinese Journal of Polymer Science 2011年第6期29卷 712-718页

作者： Javad Mokhtari mahdi Nouri Uranus Goudarzi Department of Textile Engineering Faculty of EngineeringUniversity of GuilanRashtIran

Technical properties of two naphthalimide based disperse dyes on nylon 6 and polyester fibers were investigated in the presence of urea. The two naphthalimide based disperse dyes were synthesized. The dyes were purified and then fully characterized using 1H-NMR, FTIR and melting point analysis. Dispersion of the dyes was prepared in water and applied on nylon 6 and PET fibers. The dyes offered good build-up properties on the substrates. In order to increase dye adsorption of the substrates, urea was added into the dyebath. By adding urea, the dye adsorption of polyester was increased significantly, while the increase of that of nylon 6 was not marked. The dyes showed good fastness properties on the substrates.

关键词： Naphthalimide Nylon 6 Polyester Urea Disperse dye