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Scleractinian coral communities of Hormuz Island in the PersianGulf

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Acta Oceanologica Sinica 2022年第12期41卷 48-57页

作者： Yamin Pouryousef Jafar Seyfabadi Hamid Rezai alireza Mahvari mohammad ali jafari Department of Marine Biology Faculty of Marine SciencesTarbiat Modares UniversityNoor 46417Iran Darya Negar Pars Consulting Engineers Tehran 14669Iran Department of Environment Hormozgan Provincial Directorate Bandar Abbas 79168Iran

The abundance and health of scleractinian coral communities of Hormuz Island were *** this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community *** estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very ***,12 genera were recorded,of which Porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(p<0.05).The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with *** reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.

关键词： scleractinian corals zoantharian reef health indices Hormuz Island Persian Gulf

Cryptocurrencies,gold,and WTI crude oil market efficiency:a dynamic analysis based on the adaptive market hypothesis

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Financial Innovation 2021年第1期7卷 609-634页

作者： Majid Mirzaee Ghazani mohammad ali jafari Department of Industrial Engineering K.N.Toosi University of TechnologyTehranIran

This study examined the evolving oil market efficiency by applying daily historical data to the three benchmark cryptocurrencies(Bitcoin,Ethereum,and Ripple),gold,and West Texas Intermediate(WTI)crude *** data coverage of daily returns was from August 2015 to April *** applied two alternative tests to examine linear and nonlinear dependency,i.e.,automatic portmanteau and generalized spectral *** analysis of observed results validated the adaptive market hypothesis(AMH)in all markets,but the degree of adaptability between the data was *** this study,we also analyzed the existence of evolutionary behavior in the *** achieve this goal,we checked the results by applying the rolling-window method with three different window lengths(50,100,and 150 days)on the test statistics,which was consistent with the findings of AMH.

关键词： Adaptive market hypothesis Market efficiency Cryptocurrency Evolutionary Rolling windows

Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.jafari-TALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHATIR T.CUONG-LE School of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for Engineering Application and Technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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Enhanced degradation of reactive dyes using a novel carbon ceramic electrode based on copper nanoparticles and multiwall carbon nanotubes

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Chinese Journal of Chemical Engineering 2020年第1期28卷 318-327页

作者： Fatemeh jafari Navid Nasirizadeh mohammad Mirjalili Department of Textile and Polymer Engineering Yazd BranchIslamic Azad UniversityYazdIran

A novel carbon ceramic electrode consisting of Cu NPs and MWCNT was developed to treat reactive orange 84(RO84) wastewater using ultrasound-assisted electrochemical degradation. The proposed electrode generated more hydroxyl radicals than non-nanoparticle electrodes did. In addition, a new electrochemical sensor was applied to determine residue RO84 in an aqueous medium during discoloration. This sensor is based on a glassy carbon electrode modified with gold nanourchins and graphene oxide and can detect RO84 concentration in the range of 1.0–1200 μmol·L^-1 with the detection limit of 0.03 μmol·L^-1. The degradation effects of the modified electrode on RO84 were evaluated systematically with different initial pH values, time durations, and amounts of Cu NPs and MWCNT. The results suggested that the removal efficiency of RO84 was approximately 83% after120 min of electrolysis in a phosphate buffer with pH 8.0 using a carbon ceramic electrode made with 4.0 wt%Cu NPs and 4.0 wt% MWCNT. The possible mechanism of RO84 degradation was monitored by gas chromatography–mass spectrometry, and degradation pathways were proposed.

关键词： Electrochemical degradation Carbon ceramic nanocomposite Reactive dye Copper nanoparticles

Influence of Surface Treatment on the Corrosion Resistance of Stainless Steel in Simulated Human Body Environment

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Journal of Materials Science & Technology 2009年第5期25卷 611-614页

作者： Esmaeil jafari mohammad Jafar Hadianfard Dept.of Materials Science and Engineering

In the present research, the influence of chromium enrichment by surface treatment on corrosion resistance of type 316L stainless steel in body environment was investigated. For this study, weight loss test during 18 months, cyclic and liner polarization tests before and after surface treatment and metallography by electron and light microscopy were used to evaluate the effectiveness of the proposed method. In addition, X-ray photoelectron spectroscopy （XPS） method was used to determine the chromium concentration in the surface layer after surface treatment. Results show that the surface treatment has improved corrosion resistance of the type 316L stainless steel in body environment.

关键词： Surface treatment Corrosion Passive film Polarization resistance

Numerical Study of Aeroacoustic Sound on Performance of Bladeless Fan

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 483-494页

作者： mohammad jafari Atta Sojoudi Parinaz Hafezisefat Aerospace Engineering Department Iowa State UniversityAmesUSA Mechanical Engineering Department University of TehranTehranIran Mechanical Engineering Department Iowa State UniversityAmesUSA

Aeroacoustic performance of fans is essential due to their widespread application. Therefore, the original aim of this paper is to evaluate the generated noise owing to different geometric parameters. In current study, effect of five geometric parameters was investigated on well performance of a Bladeless fan. Airflow through this fan was analyzed simulating a Bladeless fan within a 2 m×2 m×4 m room. Analysis of the flow field inside the fan and evaluating its performance were obtained by solving conservations of mass and momentum equations for aerodynamic investigations and FW-H noise equations for aeroacoustic analysis. In order to design Bladeless fan Eppler 473 airfoil profile was used as the cross section of this fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter and aspect ratio for circular and quadratic cross sections were considered. Validating acoustic code results, we compared numerical solution of FW-H noise equations for NACA0012 with experimental results. FW-H model was selected to predict the noise generated by the Bladeless fan as the numerical results indicated a good agreement with experimental ones for NACA0012. To validate 3-D numerical results, the experimental results of a round jet showed good agreement with those simulation data. In order to indicate the effect of each mentioned parameter on the fan performance, SPL and OASPL diagrams were illustrated.

关键词： Bladeless fan · Computational fluid dynamic (CFD) · Aeroacoustic performance · Ffowcs Williams and Hawkings (FW-H) formulation

One-step synthesis of Ni@Pd/NH_(2)-Fe_(3)O_(4)nanoparticles as affordable catalyst for formic acid dehydrogenation

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Chinese Journal of Chemical Engineering 2021年第4期34卷 168-174页

作者： mohammad Reza Nabid Yasamin Bide Mahsa jafari Department of Polymer&Material Chemistry Faculty of Chemistry&Petroleum ScienceShahid Beheshti UniversityTehran ***Iran

Currently,one of the critical issues in the world is finding an appropriate green alternative to fossil fuels due to the concerns about global *** a hydrogen source,formic acid has been given particular attention owing to the attractive features such as highenergy density,no toxicity,high stability at ambient temperature and high hydrogen *** an affordable and highly efficient catalyst with easy recovery from the reaction mixture for selective dehydrogenation of formic acid is still *** this report,we used a simple onestep process to synthesize Ni@Pd core shell nanoparticles on 3aminopropyltriethoxysilane modified Fe3O4 *** existence of Ni and Pd results in a synergic effect on the catalytic ***—NH2 groups play an important role for obtaining welldispersed ultrafine particles with high surface area and active *** addition,Fe3O4 lead to convenient magnetic recovery of the catalyst from reaction *** results indicate that the asprepared catalyst give the superb turnover frequency of 5367.8 h 1 with no additive,which is higher than most of the previously reported catalysts.

关键词： Core-shell Fe_(3)O_(4) Catalysis Dehydrogenation Formic acid

Application of different CFD multiphase models to investigate effects of baffles and nanoparticles on heat transfer enhancement

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Frontiers of Chemical Science and Engineering 2014年第3期8卷 320-329页

作者： ali SHAHmohammadI Arezou jafari Chemical Engineering Department Tarbiat Modares University Tehran 114-14115 Iran

In this work, the effect of baffles in a pipe on heat transfer enhancement was studied using computa- tional fluid dynamics （CFD） in the presence of Al2O3 nanoparticles which are dispersed into water. Fluid flow through the horizontal tube with uniform heat flux was simulated numerically and three dimensional governing partial differential equations were solved. To find an accurate model for CFD simulations, the results obtained by the single phase were compared with those obtained by three different multiphase models including Eulerian, mixture and volume of fluid （VOF） at Reynolds numbers in range of 600 to 3000, and two different nanoparticle concentrations （1% and 1.6%）. It was found that multi- phase models could better predict the heat transfer in nanofluids. The effect of baffles on heat transfer of nanofluid flow was also investigated through a baffled geometry. The numerical results show that at Reynolds numbers in the range of 600 to 2100, the heat transfer of nanofluid flowing in the geometry without baffle is greater than that of water flowing through a tube with baffle, whereas the difference between these effects （nanofluid and baffle） decreases with increasing the Reynolds number. At higher Reynolds numbers （2100-3000） the baffle has a greater effect on heat transfer enhancement than the nanofluid.

关键词： CFD simulation heat transfer nanofluid,baffle single phase model multiphase model

Optimal thermal design of anisotropic plates with arbitrary cutouts using genetic algorithm

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Theoretical & Applied Mechanics Letters 2022年第3期12卷 165-177页

作者： mohammad jafari Soheila Yari mohammad jafari Mechanical Engineering Department Shahrood University of TechnologyShahroodIran Faculty of Mechanical and Mechatronics Engineering Shahrood University of TechnologyShahroodIran

Anisotropic plates in different applications may have geometric defects such as openings and *** presence of the opening disturbs the heat flow,which creates significant thermal stress around the *** the heat flux is high enough,these extreme stresses can lead to structural *** article aims to obtain the optimal parameters for achieving the minimum value of the normalized stress near the cutout’s boundary in perforated anisotropic plates utilizing the genetic *** parameters include the curvature of opening’s corners,orientation angle of opening,fibers angle,heat flux angle,and opening’s *** plate is under heat flux,and the opening’s border is thermally *** stress distribution around the opening is calculated using Lekhnitskii’s complex variable method and complex potential *** genetic algorithm is then implemented to find the optimal values for design *** results show that by selecting the optimal parameters related to the anisotropic material and the opening’s geometry,the stress intensity factor of the perforated anisotropic plates is remarkably ***,this optimization algorithm can be extended to find the optimized parameters and achieve the optimal designs in anisotropic and isotropic perforated plates under thermal loadings.

关键词： Anisotropic materials Perforated plate Optimization Genetic algorithm Thermal stress Complex variable method Conformal mapping