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The capacitated multi-facility location-allocation problem with probabilistic customer location and demand: Two hybrid meta-heuristic algorithms
, Article International Journal of Systems Science ; Volume 44, Issue 10 , 2013 , Pages 1897-1912 ; 00207721 (ISSN) ; Niaki, S.T. A ; Mehdizadeh, E ; Tavarroth, M.R ; Sharif University of Technology
2013
Abstract
A new mathematical model for the capacitated multi-facility location-allocation problem with probabilistic customers' locations and demands is developed in this article. The model is formulated into the frameworks of the expected value model (EVM) and the chance-constrained programming (CCP) based on two different distance measures. In order to solve the model, two hybrid intelligent algorithms are proposed, where the simplex algorithm and stochastic simulation are the bases for both algorithms. However, in the first algorithm, named SSGA, a special type of genetic algorithm is combined and in the second, SSVDO, a vibration-damping optimisation (VDO) algorithm is united. The Taguchi method...
Open-shop production scheduling with reverse flows
, Article Computers and Industrial Engineering ; Volume 153 , 2021 ; 03608352 (ISSN) ; Akhavan Niaki, S. T ; Mehdizadeh, E ; Najafi, A. A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The purpose of this paper is to present a mixed-integer linear programming model for the scheduling problem in an open-shop manufacturing system involving reverse flows, where two job flows (direct and reverse) in two opposite directions are processed on the same machines. The aim is to minimize the maximum completion time of all jobs on all machines (i.e., the makespan). A numerical example is presented and solved using the GAMS software (version 25.1.2) to validate the proposed mathematical model. As this problem is NP-hard, a vibration damping-based optimization (VDO) algorithm is proposed to solve large-scale problems in reasonable execution times. Besides, the Taguchi experimental...
Open-shop production scheduling with reverse flows
, Article Computers and Industrial Engineering ; Volume 153 , 2021 ; 03608352 (ISSN) ; Akhavan Niaki, S. T ; Mehdizadeh, E ; Najafi, A. A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The purpose of this paper is to present a mixed-integer linear programming model for the scheduling problem in an open-shop manufacturing system involving reverse flows, where two job flows (direct and reverse) in two opposite directions are processed on the same machines. The aim is to minimize the maximum completion time of all jobs on all machines (i.e., the makespan). A numerical example is presented and solved using the GAMS software (version 25.1.2) to validate the proposed mathematical model. As this problem is NP-hard, a vibration damping-based optimization (VDO) algorithm is proposed to solve large-scale problems in reasonable execution times. Besides, the Taguchi experimental...
Simulation of a density current turbulent flow employing different RANS models: a comparison study
, Article Scientia Iranica ; Volume 16, Issue 1 , 2009 , Pages 53-63 ; 10263098 (ISSN) ; Firoozabadi, B ; Sharif University of Technology
2009
Abstract
The accuracy of Reynolds Averaged Navier-Stokes (RANS) turbulence models to predict the behavior of 2-D density currents has been examined. In this work, a steady density current is simulated by the k - ε, k - ε RNG, two-layer k - ε and modified v̄2 - f model, all of which are compared with the experimental data. Density currents, with a uniform velocity and concentration, enter a channel via a sluice gate into a lighter ambient fluid and move forward down-slope. The eddy-viscosity concept cannot accurately simulate this flow because of two stress production structures found within it. Results show that all isotropic models have a weak outcome on this current, but by improving the ability of...
Pulse Electrodeposition of Ni-Fe Composite Coating with Nano-TiO2 Particles and its Properties
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In this study, pulse electrodeposition of Ni-Fe composite coating with and without nano-TiO2 particle in sulphate bath was performed and effects of peak current density, frequency, duty cycle and type of current on their properties was investigated. Also effect of pulse parameters on the composition and amount of particles in coatings was determined. Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis was used to study the morphplogy and structure of coatings. The chemical composition of deposits was examined by Energy Dispersive X-ray Spectroscopy (EDS) attached with Scanning Electron Microscopy and Atomic Adsorption...
Edge Disjoint Spanning Trees and Eigenvalues
, M.Sc. Thesis Sharif University of Technology ; Akbari, Saeed (Supervisor)
Abstract
The spectrum of a graph is related to many important combinatorial parameters. Let (G), ′(G) be the maximum number of edge-disjoint spanning trees and edge-connectivity of a graph G,respectively. Motivated by a question of Seymour on the relationship between eigenvalues of a graph G and bounds of (G), we use eigenvalue interlacing for quotient matrix associated to graph to get the relationship between eigenvalues of a graph and bounds of (G) and ′(G). We also study the relationship between eigenvalues and bounds of (G) and ′(G) in a multigraph G. In the first chapter we prove eigenvalue interlacing and give several applications of it for obtaining bounds for characteristic numbers of...
New proline, alanine, serine repeat sequence for pharmacokinetic enhancement of anti-vegf single-domain antibody
, Article Journal of Pharmacology and Experimental Therapeutics ; Volume 375, Issue 1 , July , 2020 , Pages 69-75 ; Salimian, M ; Mehdizadeh, A ; Khosravy, M. S ; Vafabakhsh, A ; Karami, E ; Cohan, R. A ; Sharif University of Technology
American Society for Pharmacology and Experimental Therapy
2020
Abstract
Therapeutic fragmented antibodies show a poor pharmacokinetic profile that leads to frequent high-dose administration. In the current study, for the first time, a novel proline, alanine, serine (PAS) repeat sequence called PAS#208 was designed to extend the plasma half-life of a nanosized anti-vascular endothelial growth factor-A single-domain antibody. Polyacrylamide gel electrophoresis, circular dichroism, dynamic light scattering, and electrophoretic light scattering were used to assess the physicochemical properties of the newly designed PAS sequence. The effect of PAS#208 on the biologic activity of a single-domain antibody was studied using an in vitro proliferation assay. The...
Simulation of a density current turbulent flow employing different RANS models- a comparative study
, Article 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, 7 January 2008 through 10 January 2008 ; 2008 ; 9781563479373 (ISBN) ; Firoozabadi, B ; Sherif, A ; Sharif University of Technology
2008
Abstract
The accuracy of Reynolds averaged Navier-Stokes (RANS) turbulence models to predict the behavior of two-dimensional (2-D) density current has been examined. In this work, a steady density current is simulated by the κ -ε , κ -ε RNG, two-layer κ -ε and modified v 2̄ - f models. All models are compared with available experimental data. Density current with uniform velocity and concentration enters a channel via a sluice gate into a lighter ambient fluid and moves forward down-slope. The eddy-viscosity concept cannot accurately simulate this flow because of two stress production structures in it. Results show that all isotropic models have a weak outcome for this current, but with improving the...
Numerical simulation of turbid-density current using v2̄ - f turbulence model
, Article 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, 5 November 2005 through 11 November 2005 ; Volume 261 FED , 2005 , Pages 619-627 ; 08888116 (ISSN); 0791842193 (ISBN); 9780791842195 (ISBN) ; Firoozabadi, B ; Farhanieh, B ; Sharif University of Technology
2005
Abstract
The deposition behavior of fine sediment is an important phenomenon, and yet unclear to engineers concerned about reservoir sedimentation. An elliptic relaxation turbulence model (v2̄ - f model) has been used to simulate the motion of turbid density currents laden whit fine solid particles. During the last few years, the v2̄ - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proved that the v2̄ - f model to be superior to other RANS methods in many fluid flows where complex flow features are present. Due to low Reynolds number turbulence of turbidity current,(its critical Reynolds...
Study on Constraints of Design Codes for Ductile Behavior of Moment Frames with Reduced Beam Section Connections
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Mohammad Taghi (Supervisor)
Abstract
Reduced beam section connection was one of the connections that were introduced and prequalified by SAC project to replace pre-northridge connections. This connection reduces both flanges of the beam at appropriate distances from beam to column connection to make a fuse protecting welds from brittle fracture. The RBS is prequalified in limited span-to-depth ratio, for designing this connection for short and deep beams may effect its performance. Since these limitations are based on limited experiments, forty three numerical models were analysed to recheck them in this study. These models are verified based on two published experiments and are capable of predicting all known yield mechanisms...
Assessment of expression of a number of immune-related genes in the periodontitis
, Article Ecological Genetics and Genomics ; Volume 22 , 2022 ; 24059854 (ISSN) ; Badrlou, E ; Nazer, N ; Sadeghi, G ; Mehdizadeh, B ; Mirzajani, S ; Sayad, A ; Ghafouri Fard, S ; Sharif University of Technology
Elsevier Inc
2022
Abstract
Immune-related genes have essential roles in the pathobiology of periodontitis. In the current projects, we aimed at appraisal of the expression amounts of three immune-related genes including two mRNA coding genes (NR3C1 and CSTF2) and a long non-coding RNA (CCAT2) in tissue sections and blood of patients with this condition versus healthy controls. Our previous study has shown the susceptibility role of HLA-DRB1*04 allele in development of this disease. So the subjects who were positive for HLA-DRB1*04 allele were excluded. Expression amounts of CCAT2, NR3C1 and CSTF2 genes have been statistically similar between periodontitis patients and controls in both blood samples and tissue samples....
Particle trajectory study in submerged flows with baffles using ν̄2-f and k-ε turbulence models
, Article Journal of Fluids Engineering, Transactions of the ASME ; Volume 132, Issue 5 , 2010 , Pages 0511051-05110510 ; 00982202 (ISSN) ; Firoozabadi, B ; Sherif, S. A ; Sharif University of Technology
2010
Abstract
In this paper, the structure of a wall jet deflected by a baffle along with the trajectory of particles has been studied. This baffle is used to produce a stable deflected surface jet, thereby deflecting the high-velocity supercritical stream away from the bed to the surface. An elliptic relaxation turbulence model (ν̄2-f model) has been used to simulate this submerged flow. In recent years, the ν̄2- f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proven that the ν̄2- f model is superior to other Reynolds-averaged Navier-Stokes (RANS) methods in many flows where complex flow...
Particle trajectory study in submerged flows with baffles using v 2̄ - f and k -ε turbulence models
, Article 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, 7 January 2008 through 10 January 2008 ; 2008 ; 9781563479373 (ISBN) ; Sherif, A ; Firoozabadi, B ; Sharif University of Technology
2008
Abstract
In this paper, the structure of a wall jet deflected by a baffle along with the trajectory of particles has been studied. This baffle is used to produce a stable deflected surface jet, thereby deflecting the high-velocity supercritical stream away from the bed to the surface. An elliptic relaxation turbulence model (v2̄ - f model) has been used to simulate this submerged flow. During the last few years, the v2̄ - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proven that the v2̄ - f model is superior to other RANS methods in many fluid flows where complex flow features are...
Numerical simulation of submerged flows with baffles uSING ν2̄ - F and k-ε turbulence models
, Article 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006, Chicago, IL, 5 November 2006 through 10 November 2006 ; 2006 ; 08888116 (ISSN); 0791837904 (ISBN); 9780791837900 (ISBN) ; Firoozabadi, B ; Sherif, S. A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2006
Abstract
This paper introduces the concept of a submerged hydraulic jump being used for energy dissipation. A baffle wall is used to produce a stable deflected surface jet, thereby deflecting the high-velocity supercritical stream away from the bed to the surface. An elliptic relaxation turbulence model (v 2̄ - f model) has been used to simulate this submerged flow. During the last few years, the v2̄ - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proved that the v̄2 - f model is superior to other RANS methods in many fluid flows where complex flow features are present. In this study,...
Random Vibration Analysis for Multi-Story Base Isolated Structures
, M.Sc. Thesis Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
Earthquake motions are among random excitation loads. For that we used random vibration approach to estimate response of multi-degree of freedom base isolated structures under ground excitation. Some models including linear model ,nonlinear Bouc-Wen and BBW models are studied for modeling the superstructure .Several base isolation models including the laminated rubber bearing, high damping laminated rubber bearing ,resilient-friction base isolator with or without sliding upper plate and the Electricity de France system, are studied . El Centro 1940 and Mexico City 1985 earthquake which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations...
Earthquake motions are among random excitation loads. For that we used random vibration approach to estimate response of multi-degree of freedom base isolated structures under ground excitation. Some models including linear model ,nonlinear Bouc-Wen and BBW models are studied for modeling the superstructure .Several base isolation models including the laminated rubber bearing, high damping laminated rubber bearing ,resilient-friction base isolator with or without sliding upper plate and the Electricity de France system, are studied . El Centro 1940 and Mexico City 1985 earthquake which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations...
Development of an Active Guidance Method For Satellite Carrier
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoost, Hossein (Supervisor)
Abstract
A carrier should be used a guidance system for reaching to the point of injection in an orbit. The main purpose of guidance system in the injection process is issuance of guidance commands to achieve the final desirable velocity and position. These velocity and position indicate the purpose orbit for injection. Carrier is a dynamic system which is described by mathematical terms. In general carrier guidance systems apply pitch angle or rate of pitch angle to reach specific path over injection process. Different methods are available for carrier guidance such that preset method. In this method, the guidance system addresses specific guidance commands and control system performs these...
Synthesis and Characterization of Structural and Photocatalytic Properties of Ag-TiO2 Nano-Coatings
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
Titanium dioxide has covered a wide range of applications as a semiconductor photocatalyst. TiO2 is an indirect, 3.2 eV band gap semiconductor which can be stimulated using UV light. Improving the quick electron-hole recombination rate, we can enhance the photocatalytic efficiency of this semiconductor. One of the approaches in hand is to use noble metals in connection to TiO2. Among noble metals, due to its plasmonic and anti-bacterial properties and ease of preparation, silver would serve as a perfect candidate. The mechanism for photocatalytic enhancement in Ag-TiO2 structures lies behind the fact that silver can trap the photogenerated electron of TiO2 and inhibit the electron-hole...
Corporate Code of Conduct: A Kantian Perspective
, M.Sc. Thesis Sharif University of Technology ; Azadegan, Ebrahim (Supervisor)
Abstract
In the business context, the normative criteria by which moral status of individuals and organizational decision making and actions are evaluated are extracted from a recently developed discipline called the business ethics. There are various successful and unsuccessful theoretical frameworks to formulate or describe ethical norms in the business context such as consequentialism, utilitarianism, egoism, principlism, virtuism, and deontological ethics. In this dissertation, moral issues commonly raised in the economic and political system of capitalism have been investigated from a deontological point of view through the notion of “Kantian Capitalism” that was initially coined by the...
Study the Effect of Staged Construction and Behavior of Concave Corner of Excavation Stabilized by Soldier Piles with Pretensioned Anchor by 3D Numerical Modeling
, M.Sc. Thesis Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
In recent years, due to the development of cities and population growth, the number of underground floors and the depth of excavations have increased. Sustainability of excavation and control of deformation due to excavation process has always been considered as one of the important issues in geotechnical engineering. One of the most commonly used systems for deep excavation, especially in urban areas, is the soldier pile wall with tiebacks. This system consists of anchoring on soldier piles that are performed at horizontal distances around the excavation range. The cables have two parts. Unbond and bond length that, when pretensioned, have the task of transfering load out of the wedge of...
A bi-objective aggregate production planning problem with learning effect and machine deterioration: modeling and solution
, Article Computers and Operations Research ; Volume 91 , March , 2018 , Pages 21-36 ; 03050548 (ISSN) ; Akhavan Niaki, S. T ; Hemati, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The learning effects of the workers and machine deterioration in an aggregate production planning (APP) problem have not been taken into account in the literature yet. These factors affect the performance of any real-world production system and require attention. In this paper, a bi-objective optimization model is developed for an APP problem with labor learning effect and machine deterioration. The first objective of this model maximizes the profit by improving learning and reducing the failure cost of the system. The second objective function minimizes the costs associated with repairs and deterioration, which depend on the failure rate of the machines in the production periods. The aim of...