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Journal of Bionic Engineering 2018年第6期15卷 950-959页

作者： Amir Honaryar mahmoud ghiasi Faculty of Marine Technology Amirkabir University of Technology Hafez Avenue 15875-4413 Tehran Iran

The hydrodynamic characteristics and body shape of catfish, Hypostomus, are used to design and develop an Autonomous Under- water Vehicle （AUV） named ZRAUV for subsea pipeline and cable inspection. Among the hydrodynamic characteristics, stability of this bio-inspired AUV, which may be adversely affected by disturbances such as marine currents during inspection process, is taken into consideration and evaluated both numerically and experimentally. Concerning numerical investigation, computational fluid dynamics based on Reynolds Averaged Navier-Stokes equations are applied to compute the hydrodynamic damping derivatives needed for stability analysis. In order to verify the numerical predictions, computations are also performed for the well-known submarine body with a typical axisymmetric hull shape, SUBOFF. Experiments are also carried out for both proposed AUV and a conventional axisymmetric one using self-propulsion tests. Measurements of turning rate in turning circle maneuver are in reasonably good agreement with those of numerical estimations and indicate that the turning rate of conventional bodies like SUBOFF is approximately 3.8 times as great as that of bio-inspired AUV. In other words, the findings reveal that in comparison with common axisymmetric bodies, the proposed AUV with biological hull shape is more stable by about 99%, thus, it is highly suitable for subsea pipeline and cable inspection.

关键词： catfish hydrodynamic stability bio-inspired AUV hull form computational fluid dynamics

Ship Hull Form Optimization by Evolutionary Algorithm in Order to Diminish the Drag

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Journal of Marine Science and Application 2013年第2期12卷 170-179页

作者： Hassan Zakerdoost Hassan Ghassemi mahmoud ghiasi Department of Ocean Engineering Amirkabir University of Technology (A UT) Tehran 15875-4413 IRAN

This study presents a numerical method for optimizing hull form in calm water with respect to total drag which contains a viscous drag and a wave drag. The ITTC 1957 model-ship correlation line was used to predict frictional drag and the corrected linearized thin-ship theory was employed to estimate the wave drag The evolution strategy （ES） which is a member of the evolutionary algorithms （EAs） family obtains an optimum hull form by considering some design constraints. Standard Wigley hull is considered as an initial hull in optimization procedures for two test cases and new hull forms were achieved at Froude numbers 0.24, 0.316 and 0.408. In one case the ES technique was ran for the initial hull form, where the main dimensions were fixed and the only variables were the hull offsets. In the other case in addition to hull offsets, the raain dimensions were considered as variables that are optimized simultaneously. The numerical results of optimization procedure demonstrate that the optimized hull forms yield a reduction in total drag.

关键词： optimization evolutionary algorithms drag thin-shiptheory

Performance of Two Types of Mooring Systems in the Heave Motion of a Two-body Floating Wave Energy Converter

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Journal of Marine Science and Application 2019年第1期18卷 38-47页

作者： Mahdi N.Berenjkoob mahmoud ghiasi C.Guedes Soares Department of Maritime Engineering Amirkabir University of Technology Centre for Marine Technology and Ocean Engineering (CENTEC) Instituto Superior Técnico Universidade de Lisboa

This work investigated the influence of two types of mooring systems on the hydrodynamic performance of a two-body floating wave energy converter(WEC). It also investigated the effects of the physical parameters of the mooring system on the amount of extractable power from incident waves in the frequency domain. The modeled converter comprised a floating body(a buoy), a submerged body with two mooring systems, and a coupling system for two bodies. The coupling system was a simplified power take-off system that was modeled by a linear spring-damper model. The tension leg mooring system could drastically affect the heave motion of the submerged body of the model and increase relative displacement between the two bodies. The effects of the stiffness parameter of the mooring system on power absorption exceeded those of the pretension tendon force.

关键词： Two-body WEC Three-point mooring Wave energy Tension-leg mooring system Mooring parameters

Moderate concentration of citric acid for the formation of LaMnO3 and LaCoO3 nano-perovskites

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Journal of Rare Earths 2013年第10期31卷 997-1002页

作者： Elham ghiasi Azim Malekzadeh Mahnaz ghiasi School of Chemistry Damghan University

Stoichiometric LaMnO3and LaCoO3nanoparticles were synthesized via calcination of a dried solution,containing molar ratio of La(NO3)3·6H2O/[Mn(NO3)2·4H2O or Co(NO3)2·6H2O]=1 and citric acid as disperser at temperature range of 600–900 oC for 5 *** role of organic additive concentration,which was 0.0,1.0,2.5 and 5 times of the total number of moles of the nitrate ions,was investigated on phase formation,morphology,extent of crystallization and particle size of the *** were characterized by X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM)and transmission electron microscopy(TEM)*** tendency of lanthanum ion toward manganese cation was observed to be more than to cobalt cation for the formation of LaBO3(B:Mn or Co)perovskite phase.A spongy product was formed on perovskite phase formation or in the presence of citric acid.A constructive or destructive effect was observed for the organic disperser on perovskite phase formation,which depended on mole of the citric acid.

关键词： mixed oxides LaMnO3 LaCoO3 nano-perovskite citric acid rare earths

Initial estimation of hydrate formation temperature of sweet natural gases based on new empirical correlation

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Journal of Natural Gas Chemistry 2012年第5期21卷 508-512页

作者： Mohammad Mahdi ghiasi Petroleum University of Technology Ahwaz Faculty of PetroleumPost Box:63431AhwazIran

Production,processing and transportation of natural gases can be significantly affected by clathrate *** the gas analysis is crucial to predict the right conditions for hydrate ***,Katz gas gravity method can be used for initial estimation of hydrate formation temperature （HFT） under the circumstances of indeterminate gas *** far several correlations have been proposed for gas gravity method,in which the most accurate and reliable one has belonged to Bahadori and *** main objective of this study is to present a simple and yet accurate correlation for fast prediction of sweet natural gases HFT based on the fit to Katz gravity *** reviewing the error analysis results,one can discover that the new proposed correlation has the best estimation capability among the widely accepted existing correlations within the investigated range.

关键词： natural gas hydrates hydrate formation temperature gas gravity method empirical correlation

Structural Features of(Ce,La or Sr)(Mn or Co)O_3 NanoPerovskites as a Catalyst for Carbon Monoxide Oxidation

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Acta Metallurgica Sinica(English Letters) 2014年第4期27卷 635-641页

作者： Mahnaz ghiasi Azim Malekzadeh School of Chemistry Damghan University

The collection of different cations in the A and B sites of ABO3 was explored for the regularity of perovskites phase ***,Sr2？,La3？,and Ce4？are selected as the cations of site *** site B is considered to be Mn or Co *** analysis and Fourier transform infrared spectroscopy results confirm the formation of perovskite structure for catalysts in which La3？and Sr2？are considered as the cations of site *** is detected as the main crystalline phase when Ce4？is selected to be cation of site *** is found that the octahedral factor（rB/rO） takes the same important role as the tolerance factor to form cubic *** crystallite size of the products was calculated by data of the XRD and measured by the TEM *** of the XRD and TEM studies were supported by the study of the particles size distribution,which was carried out in a particle size *** perovskite samples were also used for stoichiometric oxidation of carbon monoxide with air.

关键词： Carbon monoxide Nano-perovskite Oxidation Cerium Lanthanum Strontium

Potassium phthalimide:An efficient and green organocatalyst for the synthesis of 4-aryl-7-(arylmethylene)-3,4,6,7-tetrahydro-1Hcyclopenta[d]pyrimidin-2(5H)-ones/thiones under solvent-free conditions

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Chinese Chemical Letters 2014年第2期25卷 313-316页

作者： Hamzeh Kiyani Maryam ghiasi School of Chemistry Damghan University

An efficient synthesis of Biginelli-type compounds using potassium phthalimide as a green, mild, and commercially available organocatalyst in a one-pot, multi-component cyclocondensation reaction of cyclopentanone, aldehydes, and urea/thiourea is reported. The present methodology is a green approach to access 4-aryl-7-（aryImethylene）-3,4,6,7-tetrahydro-1H-cyclopenta[d]pyrimidin-2（5H）-ones/thiones. It offers several merits such as simple operational procedures, no use of hazardous organic solvents, and cheap and environmentally friendly solid basic catalyst.

关键词： Organocatalyst Potassium phthalimide Biginelli reaction PyrimidinoneSolvent-free

Effect of soil cohesion and friction angles on reverse faults

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Earthquake Engineering and Engineering Vibration 2021年第2期20卷 329-334页

作者： Mehdi Ghafari Haslinda Nahazanan Zainuddin Md Yusoff Vahed ghiasi Department of Civil Engineering Universiti Putra MalaysiaSelangor 43400Malaysia Department of Civil Engineering Malayer UniversityMalayer 65719Iran

Severe faults have caused many earthquakes around the world throughout *** recently,earthquakes have occurred in Taiwan,China(Chi-Chi fault),and elsewhere,causing loss of lives and destroying many buildings and *** tectonic movements have gained attention from engineers,and in the past 15 years,the focus has been on faulting *** this study,a physical model(1 g)was fabricated and used to evaluate the impact of a reverse fault in a field with a *** the 1 g model,researchers installed additional gauges on the tunnel,so that all the displacements could be adjusted,and all the responses could be monitored during *** experimental study of various soil properties(cohesion and friction angles)in reverse faults on the tunnel lining were carried out and are described herein.A comparison of results for different levels of soil cohesion revealed that it can dramatically reduce the displacement by as much as 40%,and that friction angles of 27ºcan record approximately 60%more displacements than at 37º.Furthermore,a comparison of fault angles of 30ºand 60ºindicates that the displacements can be different by more than 43%in cohesionless soil and about 64%for a friction angle of 27º.

关键词： soil cohesion soil friction angle reverse faults fault angles

Prediction of blast boulders in open pit mines via multiple regression and artificial neural networks

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International Journal of Mining Science and Technology 2016年第2期26卷 183-184页

作者： ghiasi Majid Askarnejad Nematollah Dindarloo Saeid R. Shamsoddini Hamed Kusha Ma'dan Consulting Engineers Co. Tehran 11359 Iran Missouri University of Science and Technology Rolla 65409. USA Bahonar University Kerman 76169. Iran

The most important objective of blasting in open pit mines is rock *** of produced boulders(oversized crushed rocks) is a key parameter in designing blast *** this study,the amount of boulder produced in blasting operations of Golegohar iron ore open pit mine,Iran was predicted via multiple regression method and artificial neural *** of 33 blasts in the mine were collected for *** variables were:joints spacing,density and uniaxial compressive strength of the intact rock,burden,spacing,stemming,bench height to burden ratio,and specific *** dependent variable was ratio of boulder volume to pattern *** techniques were successful in predicting the *** this study,the multiple regression method was superior with coefficient of determination and root mean squared error values of 0.89 and 0.19,respectively.

关键词： Blast boulder Artificial neural networks Multiple regression Golegohar iron ore mine

Development of AZ91/SiC surface composite by FSP:effect of vibration and process parameters on microstructure and mechanical characteristics

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Advances in Manufacturing 2020年第1期8卷 82-96页

作者： Behrouz Bagheri mahmoud Abbasi Department of Mining and Metallurgy Amirkabir University of TechnologyTehranIran Faculty of Engineering University of Kashan.KashanIran

A surface composite layer enhances the mechanical characteristics of a surface while retaining the properties of the base *** stir processing(FSP)is a method for forming surface metal matrix composites(SMMCs)that reinforce a surface with *** the current study,a new method entitled friction stir vibration processing(FSVP)was applied to form SMMCs on the surface of AZ91 magnesium alloy with SiC particles as the reinforcing *** to FSP,in FSVP,the workpiece was vibrated normal to the processing line while the tool rotated and *** microstructure and mechanical properties of friction stir(FS)and friction stir vibration(FSV)processed specimens were ***,the effects of vibration frequency and process parameters on different characteristics of FS and FSV processed specimens were *** results showed that the stir zone grains for FSV processed specimens were finer than those for FS processed specimens,and the second phase particles(SiC particles)had a more homogenous distribution in the former specimens than in the latter *** was related to the effect of workpiece vibration during FSVP,which increased the material deformation and led to enhanced dynamic recrystallization and the breakdown of agglomerated SiC *** results indicated that the stir zone grain size decreased,and the distribution homogeneity of the SiC particles increased as vibration frequency *** was also observed that the stir zone grain size increased,and the mechanical properties of the processed specimens decreased as tool rotation speed increased.

关键词： Friction stir processing(FSP) Vibration AZ91 magnesium alloy Dynamic recrystallization Microstructure Mechanical properties