Vibration Analysis of Truncated FG Conical Sandwich Shell With Electrorheological Fluid Layer

, M.Sc. Thesis Sharif University of Technology Oveisi Fardouei, Masoud (Author) ; Haddadpour, Hassan (Supervisor)

Abstract

In this thesis, free vibrations of a three-layer conical shell with two FG layers and an electrorheological intermediate layer have been investigated. Also, the effects of electrical field and the FG power index that a constant related to the composition of the FG material in the shell vibration parameters (natural frequency, damping and mode shapes) have been investigated. For modeling the viscoelastic behavior in the electrorheological material, the Kelvin-Voight model and for modeling shell structure the FSDT shell model was employed. Also, in order to obtain the displacement field in the middle layer, a suitable assumption for continuity between different layers of the shell has been...

MFP-Unet: A novel deep learning based approach for left ventricle segmentation in echocardiography

, Article Physica Medica ; Volume 67 , 2019 , Pages 58-69 ; 11201797 (ISSN) Moradi, S ; GhelichOghli, M ; Alizadehasl, A ; Shiri, I ; Oveisi, N ; Oveisi, M ; Maleki, M ; Dhooge, J ; Sharif University of Technology

Associazione Italiana di Fisica Medica 2019

Abstract

Segmentation of the Left ventricle (LV) is a crucial step for quantitative measurements such as area, volume, and ejection fraction. However, the automatic LV segmentation in 2D echocardiographic images is a challenging task due to ill-defined borders, and operator dependence issues (insufficient reproducibility). U-net, which is a well-known architecture in medical image segmentation, addressed this problem through an encoder-decoder path. Despite outstanding overall performance, U-net ignores the contribution of all semantic strengths in the segmentation procedure. In the present study, we have proposed a novel architecture to tackle this drawback. Feature maps in all levels of the decoder...

Design and Efficient Implementation of Deep Learning Algorithm for ECG Classification

, M.Sc. Thesis Sharif University of Technology Oveisi, Mohammad Hossein (Author) ; Hashemi, Matin (Supervisor)

Abstract

Cardiovascular diseases are the leading cause of death globally so early diagnosis of them is important. Many researchers focused on this field. First signs of cardiac diseases appear in the electrocardiogram signal. This signal represents the electrical activity of the heart so it’s primarily used for the detection and classification of cardiac arrhythmias. Permanent monitoring of this signal is not possible for specialists so we should do this by means of Artificial Intelligence. In this thesis, we use recurrent neural networks to classify electrocardiogram’s arrhythmias. This deep learning method, use two sources of data to learn from. The first part of data is global for everyone and the...

Performance of Nanostructured TiO2 Dye-Sensitized Solar Cells by Incorporating Cubic CeO2 Particles

, M.Sc. Thesis Sharif University of Technology Oveisi, Anahita (Author) ; Mohammadi, Mohammad Reza (Supervisor)

Abstract

Dye-sensitized solar cells (DSSCs) have gained attention as an emerging technology for harnessing solar energy due to their environmental compatibility and potential as an alternative to fossil fuels. In this study, the primary objective was to enhance the performance of DSSCs by optimizing the photoanode structure through the addition of cerium oxide to titanium oxide. To achieve this, nanocomposites with varying amounts of titanium oxide and cerium oxide were synthesized. By fabricating different photoelectrodes and solar cells, the crystalline, structural, optical, and electrochemical properties of these samples were analyzed using techniques such as X-ray diffraction (XRD), scanning...

Processing study of gel-cast tubular porous NiO/SDC composite materials from gel-combustion synthesized nanopowder

, Article Journal of Sol-Gel Science and Technology ; Volume 97, Issue 3 , 2021 , Pages 581-592 ; 09280707 (ISSN) Oveisi, S ; khakpour, Z ; Faghihi sani, M. A ; Kazemzad, M ; Sharif University of Technology

Springer 2021

Abstract

In the present research, NiO–SDC (Samarium doped Ceria) nanopowder was synthesized through sol–gel combustion method using citric acid as a reducing agent (fuel) and metal nitrates as an oxidant. The characteristics of the synthesized powder were thoroughly analyzed by DTA/TG, XRD, BET and FESEM/EDX. Tubular gel-casted porous specimens of NiO–SDC (50:50 wt%) composite materials were produced after stabilizing suspensions of composite powder in an aqueous environment by addition of 3 wt% dispersant and 2.5 wt% agar as the gel builder. The effect of Dolapix CE64 as a dispersant, agar as a gel-builder and the amount of solid loadings on the processing and properties of porous ceramics was...

Metal-organic framework (MIL-100 (Fe)): synthesis, detailed photocatalytic dye degradation ability in colored textile wastewater and recycling

, Article Materials Research Bulletin ; Volume 100 , April , 2018 , Pages 357-366 ; 00255408 (ISSN) Mahmoodi, N. M ; Abdi, J ; Oveisi, M ; Alinia Asli, M ; Vossoughi, M ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

In this paper, three metal-organic frameworks (Materials of Institut Lavoisier: MILs-100 (Fe)) as porous nanomaterials were synthesized using FeCl3, Fe(NO3)3 and Fe2(SO4)3 and denoted as MIL-100-1, MIL-100-2 and MIL-100-3, respectively. The synthesized MILs-100 (Fe) were characterized by FTIR, SEM, TEM, XRD, UV–vis DRS and zeta potential. Basic Blue 41 (BB41) was used as a model dye to study the photocatalytic dye degradation ability of the synthesized metal organic frameworks. The results showed that the synthesized nanomaterials decolorized BB41. The decolorization kinetics followed first-order kinetic model. The rate constant was 0.0034, 0.0041, 0.0091 and 0.0289 (1/min) for 0.01, 0.02,...

An Investigation on the Effects of Porous Media on Propagation of Aero-acoustic Waves, Using LBM

, M.Sc. Thesis Sharif University of Technology Oveisi, Saeed (Author) ; Tayyebi Rahni, Mohammad (Supervisor) ; Massah, Hamid Reza (Co-Advisor)

Abstract

With advances in technology, production and propagation of sound waves in the air has become very important. One of the main goals of study of these waves is controlling them. The environment plays the most important role in sound propagation. Therefore, the properties of the environment and their effects should be studied. One such concern studied widespread previously, is porosity and porous media effects on the properties of a fluid flow and sound waves through it. An important application of this study is sound proofing systems. In this project two-dimensional numerical simulation of aeroacoustic waves passing through a porous media is carried out, using Lattice Boltzmann Method. The aim...

Effective removal of mercury from aqueous solution using thiol-functionalized magnetic nanoparticles

, Article Environmental Nanotechnology, Monitoring and Management ; Volume 7 , 2017 , Pages 130-138 ; 22151532 (ISSN) Oveisi, F ; Nikazar, M ; Razzaghi, M. H ; Mirrahimi, M. A. S ; Jafarzadeh, M. T ; Sharif University of Technology

Elsevier B.V 2017

Abstract

The present investigation demonstrates the effective removal of Hg(II) ions from aqueous solution by means of thiol-functionalized magnetic nanoparticles (TF-MNPs). After preparation, TF-MNPs have been characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform-infrared spectroscopy (FT-IR), Thermogravimetric (TG) and vibrating sample magnetometer (VSM). The XRD and FESEM analyses revealed the presence of magnetic nanoparticles with an average particle size of 15–30 nm. The result of FT-IR analysis confirmed that the magnetite nanoparticles have been successfully functionalized by thiol groups. The particles illustrated enough response...

Adaptation through Crowdsourcing in Disaster Management: A Complexity Theory Perspective

, Ph.D. Dissertation Sharif University of Technology Darivandi Shoushtari, Kosar (Author) ; Masoud Talebian (Supervisor) ; Shadnam, Masoud (Supervisor)

Abstract

The increasing frequency and intensity of disasters worldwide are giving rise to increasingly complex situations. Affected communities often struggle to respond effectively and rapidly using only their existing resources and infrastructure, including formal emergency response systems. In this context, voluntary efforts by citizen volunteers play an important role in enhancing communities’ adaptive capacity and resilience. Nevertheless, the considerable potential of volunteer-led disaster response is undermined by challenges related to coordination and organizing. Realizing this potential requires appropriate organizing solutions. This dissertation explores various approaches to organizing...

Optimization of a vanillin assay for determination of anthocyanins using D-optimal design

, Article Analytical Methods ; Volume 4, Issue 3 , Feb , 2012 , Pages 824-829 ; 17599660 (ISSN) Khoshayand, M. R ; Roohi, T ; Moghaddam, G ; Khoshayand, F ; Shahbazikhah, P ; Oveisi, M. R ; Hajimahmoodi, M ; Sharif University of Technology

2012

Abstract

The vanillin assay is a spectrophotometric method for anthocyanin determination that is simple, quick and inexpensive. The method is preferred because of its high sensitivity, specificity and simplicity; however, the results of this test are influenced by several factors. Hence, a D-optimal experimental design approach was investigated to simultaneously, without loss of information, optimize five factors that influence the vanillin assay: acid normality, vanillin concentration, temperature, time and acid type. Further optimization with a D-optimal design and response surface analysis (RSM) showed that a second-order polynomial model fit the experimental data appropriately. The optimum...

Long Term Effective Factors on House Price of Metropolises of Iran

, M.Sc. Thesis Sharif University of Technology Moeeni, Safoura (Author) ; Nili, Masoud (Supervisor)

Abstract

The notable share of housing sector in GDP (approximately five percent) shows this sector’s relation with macroeconomic activities. On the other hand, House as an asset leads housing sector to be affected by monetary and fiscal variables. A dynamic panel data was used in this study to evaluate the relations between housing sector and some macroeconomic variables in metropolises of Iran. As results show, in long term growth of liquidity, GDP per capita and sharp ratio have positive effects, and land per capita has negative effect on housing price in metropolises of Iran. Price increases have not been equal in different cities. Inequality of land price between metropolises and between...

Estimating an Index of Iran’s Informal Economy in 1350-1386 With Concentration on the Impact of Government’s Intervention by EMIMIC Model (The Multiple Indicators-Multiple Causes Model and Error-Correction Model)

, M.Sc. Thesis Sharif University of Technology Khandan, Abbas (Author) ; Nili, Masoud (Supervisor)

Abstract

In this research, an Index of Iran informal economy in response to the government interventions in credit, labor and product markets is stimated by EMIMIC model. To do this, first these interventions are measured using principal components analysis. In the model, the variables GDP and employment are used as indicators and taxation rates, government distortions in credit, labor and product markets, government expenditure, per capita income, unemployment and inflation as causes of the informal economy. We conclude these government interventions have affected Iran informal economy and their influence is more than indirect interventions influence such as taxation. The estimated index of Iran...

Water Quality Modeling of Urban Streams

, M.Sc. Thesis Sharif University of Technology Soltani, Maryam (Author) ; Tajrishy, Masoud (Supervisor)

Abstract

With altering natural state and increasing impervious surfaces, traditional urbanization leads to deteriorating the environment and water catchments. During the years most efforts in order to control the urban runoff outflow, have been focused on quantity; and awareness about improving water quality has been raised just in the last few years and, which emphasizes on pollution source control. Standard water quality sampling methods are time consuming, expensive and because of sampling in broad geographic areas, difficult; however modeling is a more efficient way in assessing water quality and as worries about non-point source pollution grows, different kinds of models have been used to...

The Political Economy Aspects of the Redistributive Role of Government in a General Equilibrium Micro-founded Macro Model

, M.Sc. Thesis Sharif University of Technology Zakeri, Hassan (Author) ; Nili, Masoud (Supervisor)

Abstract

The role of government in economy has been a controversial subject in economics. Lately, there has been some fundamental change in evaluating this subject. One could mention two of these as 1) realizing the importance of micro-founded macro model for evaluating policy, and 2) taking into consideration the rent-seeking behavior of politicians. In this research, a general equilibrium in a micro-founded macro model will be discussed and then in political economics framework, the effect of government on this equilibrium will be investigated. Only the redistribution role of government has been considered. First, the model in which a benevolent government is seeking optimal policy is Discussed....

Measurement of Gini Coefficients by Means of Household’s Special CPI in Iran(1984-2005)

, M.Sc. Thesis Sharif University of Technology Ghasemi, Mojtaba (Author) ; Nili, Masoud (Supervisor)

Abstract

Gini coefficient is the most prevalent index for the measurement of inequality and is usually extracted by means of nominal variables based on income or expenditures of households. In this study we have extracted more accurate Gini coefficients. By using the raw data of Households Budget Survey (HBS) and STATA software, a special CPI for each household of the sample is extracted. Subsequently nominal expenditures are deflated by these special CPIs, and at last, Gini coefficients are extracted from real expenditures. Our findings indicate that in recent years, extracted Gini coefficients are remarkably higher than prevailing ones.

Parametric Evaluation of the Y- Shaped Bracing Frame and Introducing a New Method for Design

, M.Sc. Thesis Sharif University of Technology Sedaghati, Parshan (Author) ; Mofid, Masoud (Supervisor)

Abstract

This paper investigates the behavior of the Y-shaped bracing system. Because of the special type of eccentricity in this system, the behavior of the frame is strongly dependent on the geometrical changes of the braces. So that even in the elastic region, it shows the geometrically nonlinear behavior. The amount of eccentricity is very effective on the nonlinear behavior of the frame. Also the ratio of cross sections of the bracing members has a very important impact on the expected performance of the frame. The results show that this system tolerates large displacements, and can act like a base isolation system. Firstly, using a two-dimensional accurate modeling related to the geometrical...

Assessment of Seismic Behavior Factor of Irregular Midrise Steel Structure

, M.Sc. Thesis Sharif University of Technology Baghi, Alireza (Author) ; Mofid, Masoud (Supervisor)

Abstract

The Overstrength, Ductility and the Response Modification Factor (R) for 70 steel X-braced , Inverted-V-Braced and Offcenter Bracing System frames were evaluated by performing pushover analysis of model structure with various stories (3,6,9,12&15 story) and span length (4,6&8 meter). Some result were compared with those from nonlinear dynamic analysis. According to the analysis result the R factors obtained from nonlinear dynamic analysis are 15% more than obtained from pushover analysis and R factors computed from pushover analysis were generally smaller than the values given in the design codes. R factors in Irregular structure in height are about 90% of R values in regular structure in...

Synthesis of γ-Fe2O3 Nanoparticles by Gelatin Mediator and Synthesis of γ-Fe2O3/SiO2/PCA/Ag-NPs Nanostructure Drug Delivery System

, M.Sc. Thesis Sharif University of Technology Masoud, Nazila (Author) ; Pourjavadi, Ali (Supervisor)

Abstract

Maghemite (γ-Fe2O3) nanoparticles were produced after high temperature oxidation of gelatin-Fe3O4 nanocomposite, obtained from a common coprecipitation process of Fe2+ and Fe3+ ions in an alkaline medium in the presence of a gelatin protein as an effective mediator. Size, shape, surface morphology and magnetic properties of the prepared γ-Fe2O3 nanoparticles were characterized using XRD, FTIR, TEM, SEM and VSM data. The results revealed that primary, gelatin-Fe3O4 nanocomposite had been formed and next, the gelatin decomposition in furnace produced a spinel structure of γ-Fe2O3. The effects of furnace temperature and time of heating together with the amount of gelatin on the produced...

On The Behavior of Low-Rise, Irregular, Dual Structures

, M.Sc. Thesis Sharif University of Technology Khazaei, Siamak (Author) ; Mofid, Masoud (Supervisor)

Abstract

The Response modification factor R represents the behavior of the structure such as ductility, overstrength and the inherent redundancy. This factor shall be defined according to the type of lateral force resisting system. However, there are some complexities and/or uncertainties in codes related to the R factor according to the height, form of irregularities and structural systems. Therefore, from the scientific point of view as well as reliability, it is very clear that the R factor cannot be similar for all kinds of structures, categorized as a specific group. In this investigation, assuming a low-rise, vertically irregular structure with a heliport which has a dual structural system...

Modeling Phosphorous Movement in Watersheds with SWAT (Case Study: Kan Watershed)

, M.Sc. Thesis Sharif University of Technology Delkash, Majid (Author) ; Tajrishy, Masoud (Supervisor)

Abstract

Maintaining the quality of water is of paramount importance for lakes with tourist attraction capacity. Inaccurate prediction of the quality state of lake in design phase may lead to some trouble in future. Kan River known as the main source of water feeding for the urban lake located in the north of Chitgar park passes through various villages and restaurants discharging nutrients via runoff and wastewater in the aforementioned river. Previous investigations reveal that phosphorous plays a central role in the water quality of this river and the associated downstream lake. In this research, Kan watershed,located in in the north-west of Tehran, was simulated. Considering the "Total Maximum...