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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1741-1752页

作者： Arash SAYYAH Mitra AFLAKI alireza REZAZADEH Department of Electrical and Computer Engineering University of Illinois at Urbana-ChampaignUrbanaIL 61801USA Graduate School of Management and Economics Sharif University of TechnologyTehranIran Department of Electrical and Computer Engineering Shahid Beheshti UniversityTehranIran

This paper presents a powerful application of genetic algorithm （GA） for the minimization of the total harmonic current distortion （THCD） in high-power induction motors fed by voltage source inverters, based on an approximate harmonic model. That is, having defined a desired fundamental output voltage, optimal pulse patterns （switching angles） are determined to produce the fundamental output voltage while minimizing the THCD. The complete results for the two cases of three and five switching instants in the first quarter period of pulse width modulation （PWM） waveform are presented. Presence of harmonics in the stator excitation leads to a pulsing-torque component. Considering the fact that if the pulsing-torques are at low frequencies, they can cause troublesome speed fluctuations, shaft fatigue, and unsatisfactory performance in the feedback control system, the 5th, 7th, 1 lth, and 13th current harmonics （in the case of five switching angles） are constrained at some pre-specified values, to mitigate the detrimental effects of low-frequency harmonics. At the same time, the THCD is optimized while the required fundamental output voltage is maintained.

关键词： Induction motor Genetic algorithm (GA) Optimization Pulse width modulation (PWM) Torque pulsation Totalharmonic current distortion (THCD)

Monitoring the security of audio biomedical signals communications in wearable IoT healthcare

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Digital Communications and Networks 2023年第2期9卷 393-399页

作者： Saeid Yazdanpanah Saman Shojae Chaeikar alireza Jolfaei Department of Computer Engineering Khorramabad BranchIslamic Azad UniversityKhorramabadIran Australian Institute of Higher Education SydneyAustralia College of Science and Engineering Flinders UniversityAdelaideAustralia

Smart home devices are vulnerable to a variety of *** matter gets more complicated when a number of devices collaborate to launch a colluding attack(e.g.,Distributed-Denial-of-Service(DDoS))in a network(e.g.,Smart home).To handle these attacks,most studies have hitherto proposed authentication protocols that cannot necessarily be implemented in devices,especially during Device-to-Device(D2D)*** into the potential of Ethereum blockchain and smart contracts,this work proposes a lightweight authentication mechanism that enables safe D2D interactions in a smart *** Ethereum blockchain enables the implementation of a decentralized prototype as well as a peer-to-peer distributed ledger *** work also uses a single server queuing system model and the authentication mechanism to curtail DDoS attacks by controlling the number of service requests in the *** simulation was conducted twenty times,each with varying number of devices chosen at random(ranging from 1 to 30).Each requester device sends an arbitrary request with a unique resource requirement at a *** is done to measure the system's consistency across a variety of device *** experimental results show that the proposed protocol not only prevents colluding attacks,but also outperforms the benchmark protocols in terms of computational cost,message processing,and response times.

关键词： DDoS attack Device-to-device Smart homes Blockchain Authentication Ethereum smart contract

H_∞ Consensus Control of Discrete-Time Multi-Agent Systems Under Network Imperfections and External Disturbance

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IEEE/CAA Journal of Automatica Sinica 2019年第3期6卷 667-675页

作者： Arezou Elahi alireza Alfi Hamidreza Modares IEEE the Faculty of Electrical and Robotic Engineering Shahrood University of Technology the Department of Mechanical Engineering at Michigan State University

This paper presents a distributed control protocol for consensus control of multi-agent systems(MASs) under external disturbances and network imperfections, including communication delay and random packet dropout. To comply with the discrete nature of networked systems, in contrast to most of the existing work for MASs under network imperfections,the agents are modeled by discrete-time dynamics. The communication network is considered to be undirected, its delay is considered to be time-varying but bounded, and its packet dropout is modeled by a Bernoulli distributed white *** conditions in terms of linear matrix inequalities(LMIs)for asymptotic mean-square consensus stability are derived under network imperfections without considering external disturbances.A desired disturbance attenuation level in the presence of both external disturbances and network imperfections is also provided.A simulation example is given to verify the effectiveness of the proposed approach in coping with network imperfection and disturbances.

关键词： Consensus distributed control H∞ control packet dropout stability time delay

Antibacterial properties of copper-substituted cobalt ferrite nanoparticles synthesized by co-precipitation method

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Particuology 2017年第1期15卷 158-163页

作者： alireza Samavati A. F. Ismail Advanced Membrane Technology Research Centre (AMTEC) Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia

Controlled growth and careful characterization of cobalt ferrite nanoparticles for antibacterial applica- tions are challenging. Copper-substituted cobalt ferrite nanoparticles （CuxCo1-xFe2O4）, where x = 0.0, 0.3, 0.5, 0.7 and 1.0, were synthesized using an economical and simple co-precipitation technique. The crys- tal structure and antibacterial properties of the samples as a function of Cu-substituted content were systematically studied. With increasing Cu concentration, the nanopartide size decreased from ~30 to ~20 nm. The Fourier transform infra-red spectra exhibit two prominent fundamental absorption bands, at ~595 and 419 cm^-1. These bands correspond to intrinsic stretching vibrations of metals at tetrahedral and octahedral sites, respectively. The Raman scattering results reveal that increasing the Cu content enhances the local disorder at both tetrahedral and octahedral sub lattices. The results indicate that the substitution of Co with Cu in cobalt ferrite nanoparticles strongly influences the microstructure, crystal structure, and oarticle diameter, and also improves the antibacterial properties.

关键词： Cobalt ferrite nanoparticles X-ray diffraction Raman spectroscopy Antibacterial properties

Effect of Active Gas on Weld Shape and Microstructure of Advanced A-TIG-Welded Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2016年第3期29卷 295-300页

作者： Reza Nakhaei alireza Khodabandeh Hamidreza Najafi Department of Materials Engineering Tehran Science and Research BranchIslamic Azad University

Advanced A-TIG method was conducted to increase the weld penetration and compared with the conventional TIG welding process.A two-pipeline setup was designed to apply Ar ＋ CO_2 mixed gas as the outer layer,while pure argon was applied as the inner layer to prevent any consumption of the tungsten *** results indicate that the presence of active gas in the molten pool led to the change in the temperature coefficient of surface tension so that the Marangoni convection turns inward and forms a deep weld *** increase in gas flow rate causes a decrease in the weld efficiency which is attributed to the increase in oxygen content in the weld pool and the formation o f a thicker oxide layer on the weld ***,the stir and the temperature fluctuation,led by double shielding gas,create more homogeneous nucleation sites in the molten pool so that a fine grain micros true ture was obtained.

关键词： Advanced A-TIG welding Weld metal Active gas Microstructure Marangoni convection

Inhibition Behaviour of 2-butinel,4diol and Tartrate Salt,and Their Synergistic Effects on Corrosion of AA3003 Aluminium Alloy in 0.5% NaCl Solution

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Journal of Materials Science & Technology 2008年第3期24卷 427-432页

作者： Taghi Shahrabi alireza Yazdzad Mirghasem Hosseini Department of Materials Engineering Faculty of EngineeringTarbiat Modares University Department of Physical chemistry Faculty of ChemistryTabriz University

This work intends to investigate the inhibition behaviour of 2-butine 1, 4diol and potassium sodium tartrate and their synergistic effects on 3003 aluminium alloy corrosion in 0.5% NaCl solution. Experiments were carried out by electrochemical impedance spectroscopy （EIS） and Tafel polarization method in a three-electrode cell. It was concluded that the inhibition efficiencies increased with an increase in the concentrations of inhibitors. For 2-butinel, 4diol and tartrate salt, the optimum in the inhibition efficiency, at room temperature and neutral pH, was observed for concentrations close to 10-3 mol/L and 1.5×10^-3mol/L, respectively. The electrochemical results illustrated that 2-butinel, 4diol and tartrate salt, have significant synergistic inhibition effects on corrosion of 3003 aluminium alloy in 0.5% NaCl solution. The optimum ratio of concentrations for tartrate to alcohol was 2：1.

关键词： Inhibitor 3003 aluminium alloy 2-butinel 4diol Tartrate salt

Evaluation of antioxidant enzymes activities and identification of intermediate products during phytoremediation of an anionic dye(C.I. Acid Blue 92) by pennywort(Hydrocotyle vulgaris)

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Journal of Environmental Sciences 2013年第11期25卷 2214-2222页

作者： Fatemeh Vafaei Ali Movafeghi alireza Khataee Department of Plant Biology Faculty of Natural Sciences University of Tabriz Research Laboratory of Advanced Water and Wastewater Treatment Processes Department of Applied ChemistryFaculty of Chemistry University of Tabriz

The potential of pennywort （Hydrocotyle vulgaris） for phytoremediation of C.I. Acid Blue 92 （AB92） was evaluated. The effects of various experimental parameters including pH, temperature, dye concentration and plant weight on dye removal efficiency were investigated. The results showed that the optimal condition for dye removal were pH 3.5 and temperature 25~C. Moreover, the absolute dye removal enhanced with increase in the initial dye concentration and plant weight. Pennywort showed the same removal efficiency in repeated experiments （four runs） as that obtained from the first run （a 6-day period）. Therefore, the ability of the plant in consecutive removal of AB92 confirmed the biodegradation process. Accordingly, a number of produced intermediate compounds were identified. The effect of treatment on photosynthesis and antioxidant defense system including superoxide dismutase, peroxidase and catalase in plant roots and leaves were evaluated. The results revealed a reduction in photosynthetic pigments content under dye treatments. Antioxidant enzyme responses showed marked variations with respect to the plant organ and dye concentration in the liquid medium. Overall, the increase in antioxidant enzyme activity under AB92 stress in the roots was much higher than that in the leaves. Nevertheless, no significant increase in malondialdehyde content was detected in roots or leaves, implying that the high efficiency of antioxidant system in the elimination of reactive oxygen species. Based on these results, pennywort was founded to be a capable species for phytoremediation of AB92-contaminated water, may be effective for phytoremediation dye-contaminated polluted aquatic ecosystems.

关键词： phytoremediation anionic dye Hydrocotyle vulgaris antioxidant enzymes photosynthetic pigments

Tidal modeling based on satellite altimetry observations of TOPEX/ Poseidon, Jason1, Jason2, and Jason3 with high prediction capability: A case study of the Baltic Sea

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Geodesy and Geodynamics 2024年第4期15卷 404-418页

作者： alireza A.Ardalan Asiyeh Hashemifaraz School of Surveying and Geospatial Engineering College of EngineeringUniversity of TehranTehran 11155-4563Iran

This research aims to optimize the utilization of long-term sea level data from the TOPEX/Poseidon,Jason1,Jason2,and Jason3 altimetry missions for tidal *** generate a time series of along-track observations and apply a developed method to produce tidal models with specific tidal constituents for each *** tidal modeling methodology follows an iterative process:partitioning sea surface height(SSH)observations into analysis/training and prediction/validation parts and ultimately identi-fying the set of tidal constituents that provide the best predictions at each time series *** study focuses on developing 1256 time series along the altimetry tracks over the Baltic Sea,each with its own set of tidal *** of the developed tidal models against the sSH observations within the prediction/validation part reveals mean absolute error(MAE)values ranging from 0.0334 m to 0.1349 m,with an average MAE of 0.089 *** same validation process is conducted on the FES2014 and EOT20 global tidal models,demonstrating that our tidal model,referred to as BT23(short for Baltic Tide 2023),outperforms both models with an average MAE improvement of 0.0417 m and 0.0346 m,*** addition to providing details on the development of the time series and the tidal modeling procedure,we offer the 1256 along-track time series and their associated tidal models as supplementary *** encourage the satellite altimetry community to utilize these resources for further research and applications.

关键词： Satellitealtimetry Baltic Sea Ocean tide modeling Jason3 Jason2 Jason1 TOPEX/Poseidon EOT20 FES2014

High efficiency visible-light-driven Fe_2O_3-xS_x/S-doped g-C_3N_4 heterojunction photocatalysts: Direct Z-scheme mechanism

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Journal of Materials Science & Technology 2018年第9期34卷 1511-1525页

作者： Milad Jourshabani Zahra Shariatinia alireza Badiei Department of Chemistry Amirkabir University of Technology (Tehran Polytechnic) School of Chemistry College of Science University of Tehran Nanobiomedicine Center of Excellence Nanoscience and Nanotechnology Research Center University of Tehran

Several nanoporous Fe2 O3-xSx/S-doped g-C3 N4（CNS） Z-scheme hybrid heterojuctions have been successfully synthesized by one-pot in situ growth of the Fe2O3-xSx particles on the surface of CNS. The characterization results show that S-doping in the g-C3 N4 backbone can greatly enhance the charge mobility and visible light harvesting capability. In addition, porous morphology of hybrid composite provides available open pores for guest molecules and also improves light absorbing property due to existence of multiple scattering effects. More importantly, the Fe2 O3-xSx nanoparticles formed intimate heterojunction with CNS and developed the efficient charge transfer by extending interfacial interactions occurred at the interfaces of both components. It has been found that the Fe2 O3-xSx/CNS composites have an enhanced photocatalytic activity under visible light irradiation compared with isolated Fe2 O3 and CNS components toward the photocatalytic degradation of methylene blue（MB）. The optimal loaded Fe2 O3-xSx value obtained is equal to 6.6 wt% that provided 82% MB photodegradation after 150 min with a reaction rate constant of 0.0092 min（-1） which was faster than those of the pure Fe2 O3（0.0016 min（-1））and CNS（0.0044 min（-1）） under the optimized operating variables acquired by the response surface methodology. The specific surface area and the pore volume of Fe2 O3（6.6）/CNS hybrid are 33.5 m2/g and0.195 cm3/g, which are nearly 3.8 and 7.5 times greater compared with those of the CNS, respectively. The TEM image of Fe2 O3（6.6）/CNS nanocomposite exhibits a nanoporous morphology with abundant uniform pore sizes of around 25 nm. Using the Mott-Schottky plot, the conduction and valence bands of the CNS are measured（at pH = 7） equal to-1.07 and 1.48 V versus normal hydrogen electrode（NHE）, *** tests prove that ·OH-and ·O2-radicals are major active species in the photocatalytic *** has been established that formation of the Z-scheme Fe2 O3（6.6）/CNS he

关键词： Visible light irradiation Nanophotocatalyst in situ S-doping Z-scheme heterojunction Response surface methodology(RSM)

Ground motion record simulation for structural analysis by consideration of spectral acceleration autocorrelation pattern

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 195-202页

作者： alireza Azarbakht Mahdi Sadeghi Mehdi Mousavi Department of Civil Engineering Faculty of Engineering Arak University

A novel approach is introduced to generate simulated ground motion records by considering spectral acceleration correlations at multiple periods. Most of the current reliable Ground Motion Record(GMR) simulation procedures use a seismological model including source, path and site characteristics. However, the response spectrum of simulated GMR is somewhat different when compared with the response spectrum based on recorded GMRs. More specifi cally, the correlation between the spectral values at multiple periods is a characteristic of a record which is usually different between simulated and recorded GMRs. As this correlation has a signifi cant infl uence on the structural response, it is needed to investigate the consistency of the simulated ground motions with actual records. This issue has been investigated in this study by incorporating an optimization algorithm within the Boore simulation technique. Eight seismological key parameters were optimized in order to achieve approximately the same correlation coeffi cients and spectral acceleration between two sets of real and simulated records. The results show that the acceleration response spectra of the synthetic ground motions also have good agreement with the real recorded response spectra by implementation of the proposed optimized values.

关键词： stochastic method simulation ground motion random vibration site amplifi cation EXSIM program