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Synergistic effect of seawater's parameters on the corrosion rate of the austenitic stainless steel 304

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Acta Metallurgica Sinica(English Letters) 2010年第3期23卷 161-170页

作者： S.Atashin M.Pakshir a.yazdani Department of Materials Science and Engineering Shiraz University

In this article the corrosion rate of the austenitic stainless steel type 304, under the synergistic effect of environmental factors has been assessed via potentiodynamic polarization ***, velocity, pH and temperature are the factors which induce effects on the corrosion rate of the considered *** analysis is applied using the full two-level factorial experimental design method, which results in the contribution value of each parameter in changing the quantity of average corrosion rate in both individual and synergistic *** this quantitative analysis, qualitative analysis has been used to predict the variation *** two analyses show the important role of the synergistic action, which changes the variation direction of corrosion rate and the contribution percentage of each parameter in varying the value of corrosion *** both these analyses can show the magnitude and quality of each parameter＇s effect, which is remarkably valuable in marine applications.

关键词： Stainless steel 304 Environmental parameters Seawater corrosion Synergistic effect

FINITE ELEMENT SOLUTION OF MULTI-SCALE TRANSPORT PROBLEMS USING THE LEAST SQUARES-BASED BUBBLE FUNCTION ENRICHMENT

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International Journal of Modeling, Simulation, and Scientific Computing 2012年第4期3卷 115-131页

作者： a.yazdani V.NASSEHI Department of Civil and Environmental Engineering Rice University Houston TX 77005USA Department of Chemical Engineering Loughborough University Loughborough LE113TUUK

This paper presents a technique for deriving least-squares-based polynomial bubble functions to enrich the standard linear finite elements,employed in the formulation of Galerkin weighted-residual *** element-level linear shape functions are enhanced using supplementary polynomial bubble functions with undetermined *** enhanced shape functions are inserted into the model equation and the residual functional is constructed and minimized by using the method of the least squares,resulting in an algebraic system of equations which can be solved to determine the unknown polynomial coefficients in terms of element-level nodal *** stiffness matrices are subsequently formed with the standard finite elements assembly procedures followed by using these enriched elements which require no additional nodes to be introduced and no extra degree of freedom ***,the proposed technique is tested on a number of benchmark linear transport equations where the quadratic and cubic bubble functions are derived and the numerical results are compared against the exact and standard linear element *** is demonstrated that low order bubble enriched elements provide more accurate approximations for the exact analytical solutions than the standard linear elements at no extra computational cost in spite of using relatively crude *** the other hand,it is observed that a satisfactory solution of the strongly convection-dominated transport problems may require element enrichment by using significantly higher order polynomial bubble functions in addition to the use of extremely fine computational meshes.

关键词： Bubble function finite elements least squares reaction-diffusion transport equation Galerkin method.

A Comparative Study of the Electronic and Magnetic Properties of Gd_5Ge_4 and Gd_5Si_4 Compounds

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Communications in Theoretical Physics 2014年第12期61卷 903-908页

作者： Z.Momeni Larimi A.Amirabadizadeh a.yazdani H.Arabi Department of Physics Faculty of Science University of Birjand P.O.Box 97175-615 Birjand Iran Tarbiat Modares University Tehran P.O.Box 14115-175 Iran Department of Physics Faculty of Basic Science Ferdowsi University Mashhad Iran

We present a comparative study of electronic structure and magnetic properties of Gd5Si4 and Gd5Ge4compounds using first principles full potential linearized augmented plane wave(FP-LAPW) method based on density functional theory(DFT) using the WIEN2 k code. The local-spin density approximation with correlation energy(LSDA+U) method has been used as the exchange-correlation potential. The optimized lattice constants are in good agreement with the experimental data. The total and partial density of states(DOS) of Gd5Si4 and Gd5Ge4show the difference in Si 3p-Gd 5d and Ge 4p-Gd 5d hybridization, which have an effective role in indirect exchange *** addition, the magnetic moments of Gd, Si, and Ge atoms and the compounds are calculated to clarify the differences in the magnetic properties of these compounds.

关键词： magnetocaloric compound density functional theory electronic and magnetic properties exchange interaction

Evaluating innovation ecosystem resiliency using agent-based modeling and systems dynamics

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Journal of Safety Science and Resilience 2024年第2期5卷 204-221页

作者： Soheila Abdi Mehdi yazdani Esmaeil Najafi Department of Industrial Engineering Science and Research BranchIslamic Azad UniversityTehranIran Department of Industrial Engineering Qazvin BranchIslamic Azad UniversityQazvinIran

Evaluating the resilience of the innovation ecosystem to maintain its performance,in the sense of resistance to disruption and recovery after it,has recently received more *** studies have been conducted to model different ecosystems and evaluate their ***,modeling the innovation ecosystem from a holistic perspective and performing a quantitative assessment of its resilience have received less *** paper models the innovation ecosystem holistically and evaluates its resilience index using a quantitative approach through five main *** the first step,a case study related to the innovation ecosystem of Iran's Ministry of Energy,called the Power Innovation Ecosystem,is modeled by combining system dynamics and agent-based *** validating the model in the second step,the disruption of the loss of experts is investigated in the third step,and all possible actions to recover each actor are *** the fourth step,the performance of the ecosystem is simulated before and after the disruption using the data gathered in the previous ***,resilience is calculated in two different ways in the fifth *** improvement solutions are also suggested when considering that the resilience index of the innovation ecosystem is at a medium *** research may assist policymakers in observing the resilience level of the innovation ecosystem based on the proposed *** applying strategic changes to this model,they can determine the effects of their policies and make the most appropriate decisions to increase the resilience of the innovation ecosystem.

关键词： Resilience index innovation ecosystem System dynamics Agent-based modeling

Short circuit analysis of a fault-tolerant current-limiting high temperature superconducting transformer in a power system in presence of distributed generations

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Superconductivity 2024年第1期9卷 74-86页

作者： Alireza Sadeghi Shahin Alipour Bonab Wenjuan Song Mohammad yazdani-Asrami Propulsion Electrification&Superconductivity GroupAutonomous Systems&Connectivity DivisionJames Watt School of EngineeringUniversity of GlasgowGlasgow G128QQUnited Kingdom

Power transformers are key elements for the safe and reliable delivery of electrical energy generated by renewable energy resources to consumers via transmission ***‐tolerant current‐limiting High Temperature Superconducting(FTCL HTS)transformers are type of superconducting transformers that tolerate fault for seconds and limit the fault current without the threat of burnout or delamination of tapes and deformation of *** this paper,the fault performance of a FTCL HTS transformer in a standard IEEE power system is *** studied transformer is a 50 MVA 132 kV/13.8 kV transformer where both windings are made up of HTS *** understudied power system consists of two microgrids with distributed *** of the power in microgrids is supplied by the upstream grid which is connected to the microgrids through the HTS *** fault scenarios have been considered in this power system,in each one of these scenarios,a fault happens in one of the *** considered fault scenarios have an approximate fault current of 18x to 23x of the rated current in the secondary *** showed that insulated windings in FTCL HTS transformers could substantially reduce the peak temperature of the HTS windings,compared to bare ***,post‐fault loading is imposed on the HTS windings,to observe their performance against the current increase after fault *** this case,for the first scenario of the faults,the FTCL HTS transformer could tolerate 192%of post‐fault overloading,while this number for the second fault scenario is 170%.Finally,the impact of post‐fault loading on the full recovery time was discussed.

关键词： Fault Energy Heat dissipation Heat transfer Insulation Recovery Time Temperature rise

Shear behavior and dilatancy of an artificial hard-matrix bimrock: An experimental study focusing on the role of blocky structure

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2024年第4期3卷 83-101页

作者： Amir yazdani Saeed Karimi-Nasab Hossein Jalalifar Department of Mining Engineering Isfahan University of TechnologyIsfahanIran Department of Mining Engineering Shahid Bahonar University of KermanKermanIran Department of Petroleum Engineering Shahid Bahonar University of KermanKermanIran

Bimrocks are characterized by their geotechnically significant blocky structure,presenting complex shear *** study investigates the shear behavior and dilatancy of bimrocks featuring a rock-like matrix,such as *** study addresses a gap in current research,which has predominantly examined the shear behavior of soil-matrix bimrocks(bimsoils).Laboratory direct shear tests were performed on idealized models with varying volumetric block proportions(VBPs).The results highlight that blocks exert both positive and negative effects on shear strength,dilation,and block breakage factor(BF),depending on *** indicate 40%and 60%as critical VBPs,revealing distinct shear strength trends within this range,contrary to the dominant downward *** positively impact dilation and BF between 20%and 50%VBP,while negatively affecting them beyond this *** skeleton inherently promotes stable dilatancy under normal stress increments and intensifies stress dependency of shear *** in dilation angle concerning normal stress and VBP suggest the potential for characterizing this factor using equivalent strength and roughness,akin to rockfill *** assessments of equivalent strength revealed positive effects of blocks when VBP was between 30%and 70%.Lastly,the findings indicate that blocks notably impact pre-and post-peak behaviors by reducing shear stiffness and inducing local hardening *** study also discusses the similarities and distinctions in the function of blocks within soil-like and rock-like *** offers new insights into the exact role of blocks in bimrock shear behavior beyond the traditional interpretation through the variation of friction and cohesion.

关键词： Bimrock Rock-like matrix Shear behavior Shear strength Shear dilation Block breakage

Applying the spectral stochastic finite element method in multiple-random field RC structures

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Frontiers of Structural and Civil Engineering 2022年第4期16卷 434-447页

作者： Abbas yazdani Civil Engineering Department University of Sistan and BaluchestanZahedan 98167-45845Iran

This paper uses the spectral stochastic finite element method(SSFEM)for analyzing reinforced concrete(RC)beam/slab *** doing so,it presents a new framework to study how the correlation length of a random field(RF)with uncertain parameters will affect modeling uncertainties and reliability *** considers:1)different correlation lengths for uncertainty parameters,and 2)dead and live loads as well as the elasticity moduli of concrete and steel as a multi-dimensional RF in concrete *** show the SSFEM’s efficiency in the study of concrete structures and to evaluate the sensitivity of the correlation length effects in evaluating the reliability,two examples of RC beams and slabs have been *** to the results,the RF correlation length is effective in modeling uncertainties and evaluating reliabilities;the longer the correlation length,the greater the dispersion range of the structure response and the higher the failure probability.

关键词： uncertainty spectral stochastic finite element method correlation length reliability assessment reinforced concrete beam/slab

Three-dimensional heat transfer in a particulate bed in a rotary drum studied via the discrete element method

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Particuology 2020年第4期18卷 155-162页

作者： Esmaeil yazdani Seyed Hassan Hashemabadi Computational Fluid Dynamics(CFD)Research Laboratory School of ChemicalPetroleum and Gas EngineeringIran University of Science and Technology(IUST)16846-13114 TehranIran

We simulated three-dimensional heat transfer inside a horizontal rotating drum using the discrete element method and a thermal conduction *** aim was to determine the effect of end-wall heating on thermal behavior of a granular *** simulation showed that the end-wall heating significantly affects the axial temperature profile of the bed,particularly when the length-to-diameter ratio is *** near the wall heated faster and became more thermally uniform than those in the center of the *** region affected by the end heating gradually increased over *** the rotation speed enhanced the heat conduction rate,and increasing the fill level reduced the mean temperature and thermal uniformity of the granular *** transfer was also simulated for drums with different length-to-diameter ratios.

关键词： Discrete element method Three-dimensional heat transfer Rotary drum Numerical simulation Axial temperature Particulate bed

Studies on mass attenuation coefficients for some body tissues with different medical sources and their validation using Monte Carlo codes

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Nuclear Science and Techniques 2020年第12期31卷 50-64页

作者： Sepideh yazdani Darki Sajad Keshavarz Department of Physics University of YazdYazdIran Department of Medical Radiation Engineering University of Science and Research Branch TehranTehranIran

The mass attenuation coefficients of the breasts,lungs,kidneys,pancreas,liver,eye lenses,thyroid,brain,ovary,heart,large intestines,blood,skin,spleen,muscle,and cortical bone were measured at different sources(i.e.,0.021,0.029,0.03,0.14,0.218,0.38,0.412,0.663,0.83,and 1.25 MeV)using various methods including the Monte Carlo N-particle transport code(MCNP),the geometry and tracking code(GEANT4),and theoretical approach described in this *** attenuation coefficients were also compared with the values from the national institute of standards and technology(NIST-XCOM).The values obtained were similar to those obtained using *** results show that the theoretical method is quite convenient in comparison with GEANT4 and MCNP in the calculation of the mass attenuation coefficients of the human body samples applied when compared with the NIST values and demonstrated an acceptable difference.

关键词： Mass attenuation coefficient MCNP Geant4 XCOM Human organs