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mehrali-varjani--mohsen
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A Filter-Trust-Region Method for Simple-Bound Constrained Optimization
, M.Sc. Thesis Sharif University of Technology ; Mahdavi Amiri, Nezameddin (Supervisor)
Abstract
We explain a filter-trust-region algorithm for solving nonlinear optimization problems with simple bounds recently proposed by Sainvitu and Toint. The algorithm is shown to be globally convergent to at least one first-order critical point. We implement the algorithm and test the program on various problems. The results show the effectiveness of the algorithm
An Introduction to Cosmology from the Koran Point of View, Philosophy and Science
, M.Sc. Thesis Sharif University of Technology ; Kalbasi, Hossein (Supervisor)
Abstract
Cosmology is a knowledge that deals with the matter of creation of the world, its current structure and its end. This scientific field that was a subject discussed by the scientific, philosophical and religious groups has nowadays taken the attention of many scientists and researchers. The philosophers of science, also, are not exemptions from theses groups and cosmology, as a topic common between philosophy and science, is one of the points that are under discussion in the field of philosophy of science. On the other hand, the religions, also, have noticed this issue. Koran that is the most complete divine book sent from God, has taken account of the creation and the Creator as the axis of...
Multiconverter unified power-quality conditioning system: MC-UPQC
, Article IEEE Transactions on Power Delivery ; Volume 24, Issue 3 , 2009 , Pages 1679-1686 ; 08858977 (ISSN) ; Yazdian Varjani, A ; Mokhtari, H ; Sharif University of Technology
2009
Abstract
This paper presents a new unified power-quality conditioning system (MC-UPQC), capable of simultaneous compensation for voltage and current in multibus/multifeeder systems. In this configuration, one shunt voltage-source converter (shunt VSC) and two or more series VSCs exist. The system can be applied to adjacent feeders to compensate for supply-voltage and load current imperfections on the main feeder and full compensation of supply-voltage imperfections on the other feeders. In the proposed configuration, all converters are connected back to back on the dc side and share a common dc-link capacitor. Therefore, power can be transferred from one feeder to adjacent feeders to compensate for...
Heat transfer and entropy generation analysis of hybrid graphene/Fe3O4 ferro-nanofluid flow under the influence of a magnetic field
, Article Powder Technology ; Volume 308 , 2017 , Pages 149-157 ; 00325910 (ISSN) ; Sadeghinezhad, E ; Akhiani, A. R ; Tahan Latibari, S ; Metselaar, H. S. C ; Kherbeet, A. S ; Mehrali, M ; Sharif University of Technology
Elsevier B.V
2017
Abstract
The heat transfer characteristics and entropy generation rate of hybrid graphene-magnetite nanofluids under forced laminar flow that subjected to the permanent magnetic fields were investigated. For this purpose, a nanoscale reduced graphene oxide-Fe3O4 hybrid was synthesized by using graphene oxide, iron salts and tannic acid as the reductant and stabilizer. The thermophysical and magnetic properties of the hybrid nanofluid have been widely characterized and thermal conductivity has shown an enhancement of 11%. The experimental results indicated that the heat transfer enhancement of hybrid magnetite nanofluid compared to the case of distilled was negligible when no magnetic field was...
Synthesis and properties of multi-stimuli-responsive water-soluble hyperbranched polymers prepared via reversible addition-fragmentation chain transfer self-condensing vinyl polymerization
, Article ACS Applied Polymer Materials ; 2021 ; 26376105 (ISSN) ; Kohestanian, M ; Pourjavadi, A ; Vazifehkhorani, H. H ; Mehrali, M ; Sharif University of Technology
American Chemical Society
2021
Abstract
Multistimuli-responsive hyperbranched polymers were synthesized in one-step polymerization using reversible addition-fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP). These hyperbranched polymers responded to UV-vis or sunlight, pH changes, and temperature changes. 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid known as DDMAT participated in esterification with 2-hydroxyethyl methacrylate to obtain a chain transfer monomer in the name of 2-((2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoyl)oxy)ethylmethacrylate (MACDT). For the first time, smart hyperbranched polymers were produced with the RAFT-SCVP method in one step by using...
Synthesis and properties of multi-stimuli-responsive water-soluble hyperbranched polymers prepared via reversible addition-fragmentation chain transfer self-condensing vinyl polymerization
, Article ACS Applied Polymer Materials ; Volume 4, Issue 1 , 2022 , Pages 692-702 ; 26376105 (ISSN) ; Kohestanian, M ; Pourjavadi, A ; Vazifehkhorani, H. H ; Mehrali, M ; Sharif University of Technology
American Chemical Society
2022
Abstract
Multistimuli-responsive hyperbranched polymers were synthesized in one-step polymerization using reversible addition-fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP). These hyperbranched polymers responded to UV-vis or sunlight, pH changes, and temperature changes. 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid known as DDMAT participated in esterification with 2-hydroxyethyl methacrylate to obtain a chain transfer monomer in the name of 2-((2-(((dodecylthio)carbonothioyl)thio)-2-methylpropanoyl)oxy)ethylmethacrylate (MACDT). For the first time, smart hyperbranched polymers were produced with the RAFT-SCVP method in one step by using...
Thermal performance enhancement of an evacuated tube solar collector using graphene nanoplatelets nanofluid
, Article Journal of Cleaner Production ; Volume 162 , 2017 , Pages 121-129 ; 09596526 (ISSN) ; Ong, H. C ; Ang, B. C ; Sadeghinezhad, E ; Esmaeilzadeh, A ; Mehrali, M ; Sharif University of Technology
2017
Abstract
In this study, the effect of graphene nanoplatelets (GNP)/distilled water nanofluid on the thermal performance of evacuated tube solar collector (ETSC) water heater was experimentally investigated. The mass percentage of GNP was considered at 0.025, 0.5, 0.075 and 0.1 wt%. The physical and thermal properties of the GNP nanofluids including stability, specific heat capacity, viscosity and thermal conductivity were investigated. The thermal efficiency tests on the solar collector were carried out for varying volumetric flow rate of 0.5, 0.1, and 1.5 L/min while the ASHRAE standard 93–2003 was considered to calculate the efficiency of the collector. The results indicated that the solar...
Silica nanoparticle surface chemistry: An important trait affecting cellular biocompatibility in two and three dimensional culture systems
, Article Colloids and Surfaces B: Biointerfaces ; Volume 182 , 2019 ; 09277765 (ISSN) ; Taebnia, N ; Yaghmaei, S ; Shahbazi, M. A ; Mehrali, M ; Dolatshahi Pirouz, A ; Arpanaei, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Great advantages bestowed by mesoporous silica nanoparticles (MSNs) including high surface area, tailorable pore diameter and surface chemistry, and large pore volume render them as efficient tools in biomedical applications. Herein, MSNs with different surface chemistries were synthesized and investigated in terms of biocompatibility and their impact on the morphology of bone marrow-derived mesenchymal stem cells both in 2D and 3D culture systems. Bare MSNs (BMSNs) were synthesized by template removing method using tetraethylorthosilicate (TEOS) as a precursor. The as-prepared BMSNs were then used to prepare amine-functionalized (AMSNs), carboxyl-functionalized (CMSNs) and polymeric...
Sole versus dual-sourcing under order dependent lead-times and prices [electronic resource]
, Article Computers And Operations Research, Published in: Elsevier Journals ; Volume 36, Issue 12, December 2009, Pages 3272–3280 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, we consider a dual-sourcing model with constant demand and stochastic lead times. Two suppliers may be different in terms of purchasing prices and lead-time parameters. The ordering takes place when the inventory level depletes to a reorder level, and the order is split among two suppliers. Unlike previous works in the order splitting literature, the supply lead time between vendor and buyer as well as unit purchasing prices is considered to be order quantity dependent. The proposed model finds out the optimal reorder point, order quantity and splitting proportion, using a solution procedure. Numerical results show that neglecting the relationship between ordering batch size...
Human serum protein adsorption onto synthesis nano-hydroxyapatite
, Article Protein Journal ; Volume 31, Issue 2 , February , 2012 , Pages 150-157 ; 15723887 (ISSN) ; Massah Bidgoli, M ; Behrashi, M ; Mohsen Nia, A ; Sharif University of Technology
2012
Abstract
Adsorption of human serum proteins (Albumin and total protein) onto high purity synthesis nano-hydroxyapatite (HA), Ca 10(PO 4) 6(OH) 2, has been studied in a wide temperature range by UV-visible spectrophotometer. Adsorption isotherm is basically important to describe how solutes interact with adsorbent, andiscriticalinoptimizing the use of adsorbent. Inthe present study, the experimental results werefitted tothe Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) models to obtain the characteristic parameters of each model and square of the correlation coefficients (R 2). According to the results, the DR isotherm model had the best agreement with the experimental data. The effect of...
Experimental study on heat transfer augmentation of graphene based ferrofluids in presence of magnetic field
, Article Applied Thermal Engineering ; Volume 114 , 2017 , Pages 415-427 ; 13594311 (ISSN) ; Mehrali, M ; Akhiani, A. R ; Tahan Latibari, S ; Dolatshahi Pirouz, A ; Metselaar, H. S. C ; Mehrali, M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The effect of a permanent magnetic field on the heat transfer characteristics of hybrid graphene-magnetite nanofluids (hybrid nanofluid) under forced laminar flow was experimentally investigated. For this purpose, a reduced graphene oxide-Fe3O4 was synthesized by using two-dimensional (2D) graphene oxide, iron salts and tannic acid as the reductant and stabilizer. Graphene sheets acted as the supporting materials to enhance the stability and thermal properties of magnetite nanoparticles. The thermo-physical and magnetic properties of this hybrid nanofluid have been widely characterized and it shows that the thermal conductivity increased up to 11%. The hybrid nanofluid behaves as a Newtonian...
Investigation of the Effects of Successive Liquefaction Occurrence on Piles Located in Level Ground with an Inclined Base Layer-A Physical 1g Shake Table and Laminar Shear Box Model
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
The phenomenon of soil liquefaction has caused significant damage to deep foundations of engineering structures such as bridges and buildings in past earthquakes. In recent years, many researchers have studied the effects of soil liquefaction on the pile response, but there are still many unknowns that require further research and study. The present study is part of a comprehensive research that involves several Ph.D. and master students at Sharif University of Technology (SUT). In this study, the effects of soil liquefaction on two pile 2×2 groups (one with a lumped mass and another without) in a level ground with a sloping bed were investigated. A surface non-liquefied layer was also...
Design of an Optimal Site Deployment Procedure in Different Air-Defense Scenarios
, M.Sc. Thesis Sharif University of Technology ; Fathi, Mohsen (Supervisor)
Abstract
One of the most important issues among defense is the increasing of the defense power using present facilities. Therefore, optimal setting and arrangement of equipment by considering different air-to-earth attack of enemy without knowing of properties and capabilities of available systems may not be possible. So, using defense equipment considering properties of them, and paying attention to existence restrictions and effective elements can have an effective role with the design of suitable algorithm.The main purposes of this thesis are: maximization of the efficiency of a defense system against. aerial invader targets, achieving the best arrangement of defense equipment based on suggested...
Generating a Database Through Parametric Bi-Ventricular Modeling and Finite Element Analysis of End-Diastolic Mechanical Behavior of Human Heart
, M.Sc. Thesis Sharif University of Technology ; Asghari, Mohsen (Supervisor)
Abstract
Heart failure is one of the leading causes of death around the world and diastolic dysfunction is the main culprit behind about 30 percent of them. End-diastolic pressure-volume relationship is one of the most important indices of ventricles diastolic function, however invasive nature of assessment, has hindered its use in clinical applications. Despite the advances in computational modeling and bio-mechanical simulations, computational cost of these procedures often renders the computational methods unsuitable for clinical implications. Machine learning methods are usually the proper substitute in such cases. However, this method requires a large set of pre-calculated data for training,...
Study of the Shear Stress Effect on the Behavior of Collapsible Soils and Introducing an Innovative Consecutive Model: “Three linear Stages” to Predict Behavior of Gorgan Loess
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
In all five continents, existence of collapsible soils such as Loess has been reported. These kinds of soils have mutual properties such as open structure, high void ratio and low dry density. Collapsible soils are always at risk of experiencing significant reduction in volume due to increasing water content or degree of saturation. Hence, this kind of soil can lead to serious problems including reduce of load bearing capacity, excessive deformation and failure of foundations.Collapsible soils exist in several regions of Iran. Consequently, researching their properties is a key point of geotechnical studies in our country. Hence, in past 10 years, several studies have been conducted by...
Developing Classical and Nonlocal Interlayer Shear Models for Free Vibration Analysis of Multilayer Graphene Plates
, Ph.D. Dissertation Sharif University of Technology ; Asghari, Mohsen (Supervisor)
Abstract
Experimental observations on multilayer graphene structures show that interlayer interactions including compressive and shear effects between layers are very important in their mechanical behavior. Existing analytical investigations have generally addressed the issue of pressure interactions between layers using interatomic potentials, while the models which consider the interlayer shear effect are rarely found in the literature. To address this shortcoming, this thesis presents a new formulation for multilayer graphene structures with desired shapes and boundaries, taking into account the interlayer shear effect according to the classical continuum mechanics theory. Next, size-dependent...
Numerical Modeling of the Dynamic Behavior of Piles and Pile Groups Due to Liquefaction- Induced Lateral Spreading
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
The phenomenon of lateral spreading occurs as a consequence of earthquakes induced liquefaction in grounds with mild slopes or ending to an opening. This phenomenon has caused many damages to deep foundations and associated structures. Therefore, it is necessary to study and estimate the forces which may be induced by lateral spreading to these structures. Due to the complex mechanism of the effect of lateral spreading on the piles, various tests have been carried out in the form of shaking table as well as centrifuge tests. According to the results of these tests, the forces applied to the piles are significant and can cause crucial damages to deep foundations. On the other hand, because...
Effects of Lateral Spreading on Two 2×2 Pile Groups (with and Without Lumped Mass) Using Shaking Table and Laminar Shear Box
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
Lateral spreading is the downstream movement of mild slopes or free fronts occurring due to soil liquefaction during a dynamic loading such as an earthquake. The magnitude of this movement can be from a few centimeters to tens of meters depending on parameters such as slope length, soil type, cyclic loading intensity, etc. Large displacements caused by this phenomenon can cause severe damage to some structures and infrastructures located in the direction of their movement. Numerous articles and reports of damage caused by the lateral spreading of soil have been presented during several earthquakes. Understanding this phenomenon and observing and testing its effective parameters can help...
Fracture Mechanics Analysis of Boshehr Nuclear Power Plant (BNPP) RPV during LBLOCA Using ABAQUS Software
, M.Sc. Thesis Sharif University of Technology ; Ghafari, Mohsen (Supervisor)
Abstract
In nuclear power plants (NPPs), the integrity of the Reactor Pressure Vessel (RPV) is one of the most essential issues in assessing the life of the NPPs. The RPV in a nuclear power plant cannot be replaced during plant life. Hence, maintaining the integrity of the RPV nuclear power plant is of great importance. In this study, the RPV integrity of Boshehr Nuclear Power Plant (BNPP) gainst crack formation and growth in the case of LBLOCA is evaluated and studied by the finite element method (FEM) in ABAQUS using the J-Integral method and also the weight function, which is a function of crack shape. According to the results, stress values increased significantly during the LBLOCA incident. The...