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The study of key design parameters effects on the vortex tube performance

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Journal of Thermal Science 2009年第4期18卷 370-376页

作者： Mohammad Ameri behrooz Behnia Energy Engineering Department Power & Water University of Technology

In this paper, energy separation effect in a vortex tube has been investigated using a CFD model. Thenumerical simulation has been done due to the complex structure of flow. The governing equationshave been solved by FLUENT code in 2D and 3D compressible and turbulent model. The effects ofgeometrical and thermo-physical parameters have been investigated. The results have shown that theoptimum length to diameter ratio is from 25 to 35. Increasing the number of nozzles from 2 to 4 withconvergent shape is found to be an efficient configuration for the swirl generator. The optimum valueof orifice diameter to tube diameter ratio, for the maximum cold air temperature difference and efficiency,has been determined to be around 0.58. The results show that if the inlet pressure increases upto a critical value, the efficiency will increase. Nevertheless, if it increases to higher values, the efficiencywill decrease. Moreover, it is found out that increasing the cold fraction decreases the coldtemperature difference and efficiency.

关键词： Vortex tube Energy separation Efficiency Swirl generator

Controlling chaos based on a novel intelligent integral terminal sliding mode control in a rod-type plasma torch

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Chinese Physics B 2016年第5期25卷 11-22页

作者： Safa Khari Zahra Rahmani behrooz Rezaie Intelligent Systems Research Group Faculty of Electrical and Computer EngineeringBabol Noshrivani University of Technology

An integral terminal sliding mode controller is proposed in order to control chaos in a rod-type plasma torch *** this method, a new sliding surface is defined based on a combination of the conventional sliding surface in terminal sliding mode control and a nonlinear function of the integral of the system states. It is assumed that the dynamics of a chaotic system are unknown and also the system is exposed to disturbance and unstructured uncertainty. To achieve a chattering-free and high-speed response for such an unknown system, an adaptive neuro-fuzzy inference system is utilized in the next step to approximate the unknown part of the nonlinear dynamics. Then, the proposed integral terminal sliding mode controller stabilizes the approximated system based on Lyapunov＇s stability theory. In addition, a Bee algorithm is used to select the coefficients of integral terminal sliding mode controller to improve the performance of the proposed method. Simulation results demonstrate the improvement in the response speed, chattering rejection, transient response,and robustness against uncertainties.

关键词： chaos rod-type plasma torch intelligent integral terminal sliding mode control Bee algorithm

Investigation of secondary phases and tensile strength of nitrogen-containing Alloy 718 weldment

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1259-1268页

作者： behrooz Nabavi Massoud Goodarzi Abdul Khaliq Khan School of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehran ***Iran Department of Mechanical Engineering Manitoba Institute for MaterialsUniversity of ManitobaWinnipeg R3T 2N2Canada

The influence of nitrogen content on the precipitation of secondary phases and the tensile strength of Alloy 718 during gas tungstenarc welding was investigated. Various types of precipitates were characterized using scanning electron microscopy and transmission electronmicroscopy. The results showed that in the fusion zone, the volume fraction of Nb-rich phases such as Laves, (Nb,Ti)C, and δ phases, as wellas Ti-rich phases such as (Ti,Nb)CN and (Ti,Nb)N, increased with increase in the nitrogen content due to the microsegregation of Nb and Tiwithin interdendritic areas. Nitrogen was also found to decrease the size of γ′′ particles within γ dendrites. For precipitates in the partiallymelted zone, constitutional liquation was observed for both (Nb,Ti)C and (Ti,Nb)N particles. Based on the results of tensile tests, the weld containing0.015wt% nitrogen exhibited the highest ultimate tensile strength (UTS), whereas more addition of nitrogen led to a decrease in both theUTS and yield strength due to the increased content of brittle Laves phases and decreased size of γ′′.

关键词： nitrogen secondary phases gas tungsten arc welding tensile strength Alloy 718

Supply chain network design under uncertainty with new insights from contracts

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第12期15卷 1106-1122页

作者： Mohammad Mohajer TABRIZI behrooz KARIMI Department of Industrial Engineering Amir Kabir University of Technology

In this paper, the classical problem of supply chain network design is reconsidered to emphasize the role of contracts in uncertain environments. The supply chain addressed consists of four layers: suppliers, manufacturers, warehouses, and customers acting within a single period. The single owner of the manufacturing plants signs a contract with each of the suppliers to satisfy demand from downstream. Available contracts consist of long-term and option contracts, and unmet demand is satisfied by purchasing from the spot market. In this supply chain, customer demand, supplier capacity, plants and warehouses, transportation costs, and spot prices are uncertain. Two models are proposed here: a risk-neutral two-stage stochastic model and a risk-averse model that considers risk measures. A solution strategy based on sample average approximation is then proposed to handle large scale problems. Extensive computational studies prove the important role of contracts in the design process, especially a portfolio of contracts. For instance, we show that long-term contract alone has similar impacts to having no contracts, and that option contract alone gives inferior results to a combination of option and long-term contracts. We also show that the proposed solution methodology is able to obtain good quality solutions for large scale problems.

关键词： Supply chain network design Contracts Uncertainty Conditional value at risk

Reconfiguration of Active Distribution Networks Equipped with Soft Open Points Considering Protection Constraints

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Journal of Modern Power Systems and Clean Energy 2023年第1期11卷 212-222页

作者： Ali Azizi behrooz Vahidi Amin Foroughi Nematollahi Department of Electrical Engineering of the Amirkabir University of Tech‐nology TehranIran

The purpose of active distribution networks(ADNs)is to provide effective control approaches for enhancing the operation of distribution networks(DNs)and greater accommodation of distributed generation(DG)*** the integration of DG sources into DNs,several operational problems have drawn attention such as overvoltage and power flow alteration *** problems can be dealt with by utilizing distribution network reconfiguration(DNR)and soft open points(SOPs).An SOP is a power electronic device capable of accurately controlling active and reactive power *** significant aspect often overlooked is the coordination of protection devices needed to keep the network safe from *** implementing DNR and SOPs in real DNs,protection constraints must be *** paper presents an ADN reconfiguration approach that includes DG sources,SOPs,and protection *** approach selects the ideal configuration,DG output,and SOP placement and control by employing particle swarm optimization(PSO)to minimize power loss while ensuring the correct operation of protection devices under normal and fault *** proposed approach explicitly formulates constraints on network operation,protection coordination,DG size,and SOP ***,the proposed approach is evaluated using the standard IEEE 33-bus and IEEE 69-bus networks to demonstrate the validity.

关键词： Distributed generation network reconfiguration protection system soft open point

Effects of strain-induced melt activation treatment on the microstructure and properties of Zn sacrificial anodes

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International Journal of Minerals,Metallurgy and Materials 2021年第10期28卷 1693-1704页

作者： behrooz Shayegh Boroujeny Payam Raiesi Goojani Ehsan Akbari Department of Engineering Shahrekord UniversityShahrekordIran

The microstructural properties and electrochemical performance of zinc(Zn)sacrificial anodes during strain-induced melt activation(SIMA)were investigated in this *** samples were subjected to a compressive ratio of 20%-50% at various temperatures(425-435℃)and durations(5-30 min).Short-term electrochemical tests(anode tests)based on DNV-RP-B401 and potentiodynamic polarization tests were performed in 3.5wt%NaCl solution to evaluate the electrochemical efficiency and corrosion behavior of the samples,*** electrochemical test results for the optimum sample confirmed that the corrosion current density declined by 90% and the anode efficiency slightly decreased relative to that of the raw ***-dispersive X-ray spectroscopy,scanning electron microscopy,metallographic images,and microhardness profiles showed the accumulation of alloying elements on the boundary and the conversion of uniform corrosion into localized corrosion,hence the decrease of the Zn sacrificial anode’s efficiency after the SIMA process.

关键词： strain-induced melt activation process zinc sacrificial anode corrosion resistance anode test

Classical and Inverse Median Location Problems under Uncertain Environment

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Acta Mathematicae Applicatae Sinica 2020年第2期36卷 419-438页

作者： Akram SOLTANPOUR Fahimeh BAROUGHI behrooz ALIZADEH Department of Applied Mathematics Faculty of Basic SciencesSahand University of TechnologyTabrizIran

In this paper,we first consider the classical p-median location problem on a network in which the vertex weights and the distances between vertices are uncertain *** uncertainty distribution of the optimal objective value of the p-median problem is given and the concepts of the α-p-median,the most p-median and the expected p-median are ***,it is shown that the uncertain p-median problem is NP-hard on general ***,if the underlying network is a tree,an efficient algorithm for the uncertain 1-median problem with linear time complexity is ***,we investigate the inverse 1-median problem on a tree with uncertain vertex weights and present a programming model for the ***,it is shown that the proposed model can be reformulated into a deterministic programming model.

关键词： location problem p-median inverse optimization uncertainty theory uncertain programming

Combinatorial Algorithms for Reverse Selective Undesirable Center Location Problems on Cycle Graphs

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Journal of the Operations Research Society of China 2017年第3期5卷 347-361页

作者： Roghayeh Etemad behrooz Alizadeh Department of Applied Mathematics Faculty of Basic SciencesSahand University of TechnologyTabrizIran

This paper deals with a general variant of the reverse undesirable(obnoxious)center location problem on cycle *** a‘selective’subset of the vertices of the underlying cycle graph as location of the existing customers,the task is to modify the edge lengths within a given budget such that the minimum of distances between a predetermined undesirable facility location and the customer points is maximized under the perturbed edge *** develop a combinatorial O(n log n)algorithm for the problem with continuous *** the uniform-cost model,we solve this problem in linear time by an improved ***,exact solution methods are proposed for the problem with integer modifications.

关键词： Undesirable center location Reverse optimization Combinatorial optimization Time complexity

Optimal Algorithms for Integer Inverse Undesirable p-Median Location Problems on Weighted Extended Star Networks

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Journal of the Operations Research Society of China 2021年第1期9卷 99-117页

作者： Esmaeil Afrashteh behrooz Alizadeh Fahimeh Baroughi Department of Applied Mathematics Faculty of Basic SciencesSahand University of TechnologyTabrizIran

This paper is concerned with the problem of modifying the edge lengths of a weighted extended star network with n vertices by integer amounts at the minimum total cost subject to be given modification bounds so that a set of p prespecified vertices becomes an undesirable p-median location on the perturbed *** call this problem as the integer inverse undesirable p-median location *** combinatorial algorithms with O(p2n logn)and O(p2(n logn+n log nmax))running times are proposed for solving the problem under the weighted rectilinear and weighted Chebyshev norms,***,it is shown that the problem under the weighted sum-type Hamming distance with uniform modification bounds can be solved in O(p-n log n)time.

关键词： Undesirable p-median location Combinatorial optimization Inverse optimization Time complexity