Static Melt Crystallizer Simulation and Design with CFD

, M.Sc. Thesis Sharif University of Technology Karimzadeh Sureshjani, Hamed (Author) ; Farhadi, Fathollah (Supervisor) ; Pishvaei, Mahmood Reza (Supervisor)

Abstract

Layer melt crystallization is one of the most attractive and productive separation methods in the chemical industry. One of the most important coal tar components, which is present in concentration between 10 to 12% is naphthalene. One of the most commonly used techniques for producing naphthalene crystallization. In this thesis, the layer melt crystallization in a mixture of naphthalene and benzothiophene has been investigated using computational fluid dynamics. The simulation of crystallization was performed in Comsol Multiphisics version 5.6 and the thickness of the crystal layer was obtained according to the time. At first, simulation results were verified with the labroratory results of...

Semi-myopic algorithm for resource allocation in wireless body area networks

, Article IET Wireless Sensor Systems ; Volume 8, Issue 1 , January , 2018 ; 20436386 (ISSN) Karimzadeh Farshbafan, M ; Ashtiani, F ; Sharif University of Technology

Institution of Engineering and Technology 2018

Abstract

The key features of wireless body area networks are limited energy resources of the sensor nodes and the need for highly reliable packet transmission. Therefore, designing a suitable algorithm that schedules transmission of the nodes is very important. Although an optimal algorithm has been previously reported based on a partially observable Markov decision process (POMDP), its complexity is high. In this study, the authors propose a suboptimal algorithm for scheduling the transmissions, i.e. a semi-myopic algorithm, with a performance close to the optimal, albeit with much lower complexity. To this end, they modify the structure of the cost function of the optimal algorithm such that the...

Impedance control of a two degree-of-freedom flexible link manipulator using singular perturbation and sliding mode control theory

, Article Proceedings of the 7th Biennial Conference on Engineering Systems Design and Analysis - 2004, Manchester, 19 July 2004 through 22 July 2004 ; Volume 1 , 2004 , Pages 851-860 ; 0791841731 (ISBN); 9780791841730 (ISBN) Karimzadeh, A ; Vossoughi, G. R ; Sharif University of Technology

American Society of Mechanical Engineers 2004

Abstract

In this article, impedance control of a two link flexible link manipulators is addressed. The concept of impedance control of flexible link robots is rather new and is being addressed for the first time. Impedance Control provides a universal approach to the control of flexible robots - in both constrained and unconstrained maneuvers. The initial part of the paper concerns the use Hamilton's principle to derive the mathematical equations governing the dynamics of joint angles, vibration of the flexible links and the constraining forces. The approximate elastic deformations are then derived by means of the Assumed-Mode-Method (AMM). Using the singular perturbation method, the dynamic of the...

Stress field in the thermoelastic rolling contact of graded coatings

, Article Archive of Applied Mechanics ; Volume 88, Issue 10 , 2018 , Pages 1805-1814 ; 09391533 (ISSN) Nili, A ; Adibnazari, S ; Karimzadeh, A ; Sharif University of Technology

Springer Verlag 2018

Abstract

The thermoelastic rolling contact problem for an FGM-coated half plane under the plane strain deformation is studied in this paper. A rigid roller rolls over the surface of coating with constant translational velocity generating frictional heating in the slip zones of the contact patch. The material properties of the FGM vary exponentially along the thickness direction. It is assumed that the contact area consists of a central stick zone and two slip zones of the same sign. The transfer matrix method and Fourier integral transform technique are used to achieve a system of two Cauchy singular integral equations. The coupling effect of tangential traction is eliminated by adapting the...

Rolling contact mechanics of graded coatings involving frictional heating

, Article Acta Mechanica ; Volume 230, Issue 6 , 2019 , Pages 1981-1997 ; 00015970 (ISSN) Nili, A ; Adibnazari, S ; Karimzadeh, A ; Sharif University of Technology

Springer-Verlag Wien 2019

Abstract

The two-dimensional thermoelastic tractive rolling contact problem for a half-plane which is coated with a functionally graded material (FGM), under the plane strain deformation, is studied in this paper. A rigid cylinder rolls over the surface of an FGM coating with constant translational velocity, generating frictional heating in the slip zones of the contact area. Thermomechanical properties of the FGM vary exponentially along the thickness direction. It is assumed that the contact area consists of a central stick zone and two slip zones of the same sign. The transfer matrix method and Fourier integral transform technique are used to achieve a system of two Cauchy singular integral...

Artificial neural network modeling for evaluating of epitaxial growth of Ti6Al4V weldment

, Article Materials Science and Engineering A ; Volume 432, Issue 1-2 , 2006 , Pages 184-190 ; 09215093 (ISSN) Karimzadeh, F ; Ebnonnasir, A ; Foroughi, A ; Sharif University of Technology

2006

Abstract

The effect of epitaxial growth on microstructure of Ti-6Al-4V alloy weldment was examined by artificial neural networks (ANNs). The microplasma arc welding (MPAW) procedure was performed at different currents, welding speeds and flow rates of shielding and plasma gas. Microstructural characterizations were studied by optical and scanning electron microscopy (SEM). Finally, an artificial neural network was developed to predict grain size of fusion zone (FZ) at different currents and welding speeds. The results showed that a coarse primary β phase develops in the fusion zone as a result of epitaxial nucleation on coarsened β grains near the heat affected zone (NHAZ) which grow competitively...

An efficient tabu search algorithm for the single row facility location problem [electronic resource]

, Article European Journal Of Operational Research ; Vol. 205, No. 1, pp. 98-105 Samarghandi, H. (Hamed) ; Eshghi, Kourosh ; Sharif University of Technology

Abstract

The general goal of the facility layout problem is to arrange a given number of facilities to minimize the total cost associated with the known or projected interactions between them. One of the special classes of the facility layout problem is the Single Row Facility Layout Problem (SRFLP), which consists of finding an optimal linear placement of rectangular facilities with varying dimensions on a straight line. This paper first presents and proves a theorem to find the optimal solution of a special case of SRFLP. The results obtained by this theorem prove to be very useful in reducing the computational efforts when a new algorithm based on tabu search for the SRFLP is proposed in this...

Sensitivity analysis of matching pennies game [electronic resource]

, Article Mathematical and Computer Modelling ; Volume 51, Issues 5–6, March 2010, Pages 722–735 Yarmand, H. (Hamed) ; Eshghi, Kourosh ; Sharif University of Technology

Abstract

In this paper, we have discussed the results of sensitivity analysis in a payoff matrix of the Matching Pennies game. After representing the game as a LP model, the sensitivity analysis of the elements of the payoff matrix is presented. The game value and the optimal strategies for different values of parameters are determined and compared

Corrosion behavior of aluminum 6061 alloy joined by friction stir welding and gas tungsten arc welding methods

, Article Materials and Design ; Volume 39 , 2012 , Pages 329-333 ; 02641275 (ISSN) Fahimpour, V ; Sadrnezhaad, S. K ; Karimzadeh, F ; Sharif University of Technology

2012

Abstract

Wrought aluminum sheets with thickness of 13. mm were square butt-welded by friction stir welding (FSW) and gas tungsten arc welding (GTAW) methods. Corrosion behavior of the welding zone was probed by Tafel polarization curve. Optical metallography (OM) and scanning electron microscopy together with energy dispersive spectroscopy (SEM-EDS) were used to determine morphology and semi-quantitative analysis of the welded zone. FSW resulted in equiaxed grains of about 1-2 μm, while GTAW caused dendritic structure of the welded region. Resistance to corrosion was greater for the FSW grains than the GTAW structure. In both cases, susceptibility to corrosion attack was greater in the welded region...

Microstructure and mechanical property change during FSW and GTAW of Al6061 alloy

, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 44, Issue 5 , 2013 , Pages 2187-2195 ; 10735623 (ISSN) Fahimpour, V ; Sadrnezhaad, S. K ; Karimzadeh, F ; Sharif University of Technology

2013

Abstract

The variation of morphology and mechanical properties of Al6061 automotive aluminum alloy due to friction stir welding (FSW) and gas tungsten arc welding (GTAW) was investigated by optical metallography, scanning electron microscopy, microhardness measurement, X-ray diffraction, tensile testing, and fractography. The center-line dendrite emergence and microhardness reduction in the heat-affected zone were observed in the GTAW process. Although similar microhardness reduction with respect to the base metal was observed in the FSW samples, higher HVs were obtained for the FSW rather than the GTAW process at almost all heat-affected locations. Ultimate tensile strengths of the FSW and the GTAW...

Effect of size dependency on in-plane vibration of circular micro-rings

, Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 1996-2008 ; 10263098 (ISSN) Karimzadeh, A ; Ahmadian, M. T ; Rahaeifard, M ; Sharif University of Technology

Sharif University of Technology 2017

Abstract

In this paper, based on the modified couple stress theory, the size-dependent dynamic behavior of circular rings on elastic foundation is investigated. The ring is modeled by Euler-Bernoulli and Timoshenko beam theories, and Hamilton's principle is utilized to derive the equations of motion and boundary conditions. The formulation derived is a general form of the equation of motion of circular rings and can be reduced to the classical form by eliminating the size-dependent terms. On this basis, the size-dependent natural frequencies of a circular ring are calculated based on the non-classical Euler-Bernoulli and Timoshenko beam theories. The findings are compared with classical beam...

Development of Dynamic Simple Shear Apparatus for Small Strain Dynamic Tests on Unsaturated Granular Soils by Bender Element and ultrasonic Sensors

, M.Sc. Thesis Sharif University of Technology Karimzadeh, Ali Akbar (Author) ; Jafarzadeh, Fardin (Supervisor)

Abstract

Shear modulus and confined modulus are important parameters for static and dynamic analysis in geotechnical applications. Elastoplastic and nonlinear constitutive models has been formulized by these parameters. Cyclic simple shear apparatus had been developed by mounting bender element and ultrasonic sensor to measure continuous shear wave and pressure wave velocities for determination of G_max and M.For this purpose two new pedestals have been fabricated on which HAE ceramic disc and sensors were mounted. A pressure control panel and a hanging column system have been designed to apply high and low matric suction with high accuracy.At first two small strain tests were conducted for...

Design and implementation of brain surgery bipolar electrocautery simulator using haptic technology

, Article Iranian Journal of Science and Technology - Transactions of Electrical Engineering ; Volume 47, Issue 3 , 2023 , Pages 859-869 ; 22286179 (ISSN) Karimzadeh, R ; Sheikh, J ; Azarnoush, H ; Arabi, H ; Sharif University of Technology

Institute for Ionics 2023

Abstract

Surgical simulators have been widely used in training and evaluation of physicians and surgeons. Virtual reality augmented with haptic technology has made it feasible to develop more realistic surgical simulators. In this context, we set out to design and develop a brain surgery bipolar electrocautery simulator using haptic technology. A 3D model of brain tissue was generated based on a brain craniotomy image. Bipolar forceps were also modeled to visually assimilate real forceps. An experiment was developed to assess the learning process of the participants. In this experiment, the volunteers were asked to cauterize a large blood vessel in the brain while minimizing the damage done to the...

The effect of gas mixture of post-oxidation on structure and corrosion behavior of plasma nitrided AISI 316 stainless steel

, Article Applied Surface Science ; Volume 283 , 2013 , Pages 584-589 ; 01694332 (ISSN) Karimzadeh, N ; Moghaddam, E. G ; Mirjani, M ; Raeissi, K ; Sharif University of Technology

2013

Abstract

In this research, microstructure and corrosion properties of plasma nitriding and post-oxidation treated AISI 316 austenitic stainless steel have been studied. The plasma nitriding treatment was carried out at 450 C for 5 h in a D.C. plasma setup with a gas mixture of 25% N2-75% H2 followed by post-oxidation in gas mixtures of O2/H2: 1/3, 1/5, 1/9 and 1/12 for 30 min. The treated samples were characterized by SEM, XRD and roughness testing. Potentiodynamic and cyclic polarization tests were also employed to evaluate the corrosion resistance of the samples. The results showed that plasma nitriding treatment decreases corrosion resistance of the steel substrate. However, post-oxidizing...

Biodecolourization of Azo dye under extreme environmental conditions via klebsiella quasipneumoniae gt7: mechanism and efficiency

, Article Journal of Environmental Health and Sustainable Development ; Volume 7, Issue 2 , 2022 , Pages 1660-1675 ; 24766267 (ISSN) Karimzadeh, M ; Lotfabad, T. B ; Heydarinasab, A ; Yaghmaei, S ; Sharif University of Technology

Shahid Sadoughi University of Medical Sciences 2022

Abstract

Introduction: Biodegradation of azo dyes under harsh environmental conditions has been of great interest for the treatment of colored effluents. The present study aims to evaluate Klebsiella quasipneumoniae GT7 for degrading azo dye Carmoisine under extreme pH conditions and high salinity. Materials and Methods: The growth profiles of bacteria were compared under different conditions of salinity and pH, using the optical density and viability measurements. Kinetic patterns of decolourization by GT7 were investigated under different concentrations of NaCl and/or pH, through the spectrophotometry method. Moreover, thin layer chromatography (TLC) was used to evaluate the biotransformation of...

A novel analysis of critical water pollution in the transboundary Aras River using the Sentinel-2 satellite images and ANNs

, Article International Journal of Environmental Science and Technology ; Volume 19, Issue 9 , 2022 , Pages 9011-9026 ; 17351472 (ISSN) Fouladi Osgouei, H ; Zarghami, M ; Mosaferi, M ; Karimzadeh, S ; Sharif University of Technology

Springer Science and Business Media Deutschland GmbH 2022

Abstract

Recently, remote sensing considered as important tool in studies of water quality issues. The Aras River flows across a transboundary basin in northern Iran. In this study, the aim is to model the water quality parameters (WQPs) using remote sensing and an artificial neural network (ANN), which is a new method proposed to find WQPs based on multivariate regression approaches. The relationship between WQPs and digital data from the Sentinel-2 satellite was determined to estimate and map the WQPs in this river. Using the field data and digital image data, the obtained results show that multivariate regression approaches and high-resolution remote sensing could monitor and predict the...

Parametric study and computation of seismic performance factors of braced shear panels

, Article Scientia Iranica ; Volume 23, Issue 2 , 2016 , Pages 460-474 ; 10263098 (ISSN) Hamed, A ; Mofid, M ; Sharif University of Technology

Sharif University of Technology 2016

Abstract

By locating a steel shear panel on the intersection point of the X-braces, concentrically or eccentrically braced shear panel (CBFSP or EBFSP) is formed. In this paper, to perform parametric study, 1-story CBFSP and EBFSP models with span length greater or less than height are considered. Using linear static analyses, the effects of size and location of the shear panel on the lateral stiffness of the frame with respect to the moment resisting frame with the same member sections are investigated. Next, for 1- And 3-story models, maximum displacement, along with base shear, and the ratio between the dissipated energy and input energy are examined under 4 ground motion records. Behavior of the...

Assessment of Seismic Retrofit Policies for Buildings

, M.Sc. Thesis Sharif University of Technology Movahedi, Ali (Author) ; Kashani, Hamed (Supervisor)

Abstract

Occurrence of natural disasters such as earthquake could seriously damage most buildings especially those with insufficient resistance located in urban worn-out textures. In order to reduce unpleasant consequences of an earthquake, appropriate policies need to be considered to persuade the beneficiaries to follow retrofitting standards in the process of planning, designing, and construction of buildings. These policies shall be implemented through institutions in arbitrary or obligatory forms, by encouragement or penalty mechanisms. In order to consider these policies, first of all we need to identify the beneficiaries and their particulars. By studying and considering subjects discussed in...

Optimal-Robust Control of Drug Delivery in Cancer Chemotherapy

, M.Sc. Thesis Sharif University of Technology Hosseini, Fatemeh (Author) ; Moradi, Hamed (Supervisor)

Abstract

Chemotherapy is a proven and effective systematic approach to treat various types of cancers. Despite its advantages, chemotherapy would kill healthy as well as cancer cells. To overcome this problem, different controlling strategies are implemented. This study aims to provide a medicine drug delivery schedule for chemotherapy (by designing a proper controlling system) based on the verifiable mathematical models. First, the dynamic model is analysed and stability points are reviewed. The selected model has five state variables and two inputs. In this study, the focus is on dynamic model analysis and obtaining an effective and appropriate treatment pattern by designing a proper controller. To...

Real Options Analysis Framework for the Optimal Timing of Network Infrastructure Systems Retrofits

, M.Sc. Thesis Sharif University of Technology Roghani, Mehran (Author) ; Kashani, Hamed (Supervisor)

Abstract

Natural disasters can damage the infrastructure of society. Damages to the infrastructure components of society can disrupt their service delivery. Disruption in providing services to society's infrastructure can disrupt social and economic activities and impose various significant costs on society. The cost of repairing the damaged infrastructure and reducing the income of households are among the economic damages of accidents. The decline in the quality of life, as well as the death and injury of people due to the breakdown of the infrastructure or the disruption in their services, are among the social damages caused by accidents. In the same way, natural disasters are considered a...