Active Vibration Suppression of Laminated Composite Structures Integrated with Magnetorheological Fluid Segments under Random Excitation

, M.Sc. Thesis Sharif University of Technology Fattahi Massoom, Zahra (Author) ; Zabihollah, Abolghasem (Supervisor)

Abstract

Magnetorheological (MR) materials indicate variations in their rheological properties when subjected to different magnetic fields. They have quick time response, in the order of milliseconds, and therefore are potentially applicable to structures and devices when a tunable system response is required. This study presents vibration analysis of laminated composite plate using MR fluid lumps under Random Excitation. A structural dynamic modeling approach is discussed and vibration characteristics of MR adaptive structures are predicted for different magnetic field levels. Linear Quadratic Regulator (LQR) controller is designed to achieve the vibration suppression of the laminated plate. The...

Theoretical Investigation of Hydrogen Bonding Effects on Interaction of Metal Nanoclusters with Histidine, Oxidation of Olefins by MnO4– & Acidity Enhancement of Alcohols

, Ph.D. Dissertation Sharif University of Technology Jebeli Javan, Marjan (Author) ; Fattahi, Alireza (Supervisor) ; Mahmoodi Hashemi, Mohammad (Supervisor) ; Jamshidi, Zahra (Supervisor)

Abstract

This thesis is divided into three parts: In part I, interactions of neutral and anionic forms of histidine with coinage metal nano clusters M3 (M = Au, Ag and Cu) are investigated. Results demonstrate that nonconventional M…H-O hydrogen bonds and M-X bonds (X = N, O) play stabilization roles in interactions of histidine and metal nano clusters. Presence of negative charge in ligand leads to increase of binding energy of complexes. In the next step, the effects of coinage metal nano clusters on the gas-phase acidity of weak organic acid (histidine) have been explored. The acidity of isolated histidine is compared with the acidity of its Au3–, Ag3– and Cu3–complexed species. Moreover, pKa...

Theoretical Investigation of Hydrogen Bonding Effects on Interaction of Metal Nanoclusters with Biomolecules & Acidity Enhancement of Alcohols

, Ph.D. Dissertation Sharif University of Technology Ali Akbar Tehrani, Zahra (Author) ; Fattahi, Alireza (Supervisor) ; Mahmoodi Hashemi, Mohammad (Supervisor) ; Jamshidi, Zahra (Co-Advisor)

Abstract

This thesis is divided into three parts: In part I, conformational properties of neutral, anionic, cationic and zwitterionic forms of glutathione tripeptide were investigated by means of DFT-B3LYP method with 6-31+G (d,p) basis set. Results show that glutathione is a very flexible molecule and its conformational energy landscape is strongly influenced by forming intramolecular hydrogen bond and its charge. Conformation of each amino acid in glutathione tripeptide depends on its orientation within the peptide sequence in addition to the conformation of other amino acids within the chain. Investigation of intramolecular hydrogen bonds in these conformers by means of AIM analysis demonstrates...

Modelling of fischer-tropsch synthesis in a fluidized bed reactor

, Article Advanced Materials Research ; Volume 586 , 2012 , Pages 274-281 ; 10226680 (ISSN) ; 9783037855232 (ISBN) Kazemeini, M ; Maleki, R ; Fattahi, M

2012

Abstract

The FT reaction involves the conversion of syngas which is derived from natural gas or coal to different kinds of products according to the operating conditions and the type of the catalyst. In other words, it is a practical way to convert solid fuel (coal) and natural gas to various hydrocarbons (C1-C60) and oxygenates such as alkanes, alkenes etc. The main products of the reaction are naphtha and gasoline. This paper deals with developing a proper product distribution model for FT process using the appropriate kinetic model, optimizing the respective rate constants while applying them in product distribution equations. The results revealed only 8.09% deviations from the olefin experimental...

Mesoporous silica nanoparticles (MCM-41) coated PEGylated chitosan as a pH-Responsive nanocarrier for triggered release of erythromycin [electronic resource]

, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2014, Volume 63, Issue 13, Pages 692-697 Pourjavadi, A. (Ali) ; Mazaheri Tehrani, Zahra ; Sharif University of Technology

Abstract

A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5

Novel manufacturing process of nanoparticle/Al composite filler metals of tungsten inert gas welding by accumulative roll bonding

, Article Materials Science and Engineering A ; Volume 648 , 2015 , Pages 47-50 ; 09215093 (ISSN) Fattahi, M ; Noei Aghaei, V ; Dabiri, A. R ; Amirkhanlou, S ; Akhavan, S ; Fattahi, Y ; Sharif University of Technology

Elsevier Ltd 2015

Abstract

In the present work, accumulative roll bonding (ARB) was used as an effective method for manufacturing nanoparticle/Al composite filler metals of tungsten inert gas (TIG) welding. After welding, the distribution of ceramic nanoparticles and mechanical properties of welds were investigated. By applying ARB, ceramic nanoparticles were uniformly dispersed in the composite filler metals. Consequently, the welds produced by these filler metals had a uniform dispersion of ceramic nanoparticles in their compositions. The test results showed that the yield strength of welds was greatly increased when using the nanoparticle/Al composite filler metals. The improvement in the yield strength was...

Conversion of a weak organic acid to a super acid in the gas phase

, Article Journal of Physical Organic Chemistry ; Volume 21, Issue 2 , 2008 , Pages 112-118 ; 08943230 (ISSN) Fattahi, A ; Tavasoli, E ; Sharif University of Technology

2008

Abstract

The effects of selected metal ions on the gas-phase acidity of weak organic acids have been explored using the DFT and Moller-Plesset Perturbation Theory (MP2) calculations. The three organic acids selected for this study were acetic acid (aliphatic), benzoic acid (aromatic), and glycine (amino acid). The acidities of these compounds are compared with the acidity of their Li +-, Na+-, and K+ -complexed species. The results indicate that upon complexation with Li+, Na+, and K+ at 298K, the gas-phase acidity of acetic acid, for example, varies from 345.3 to 218.8, 230.2, and 240.1 kcal/mol, respectively (i.e., its dissociation becomes much less endothermic). These values indicate that a weak...

Direct Torque Control of Brushless Doubly-Fed Induction Machines Using Fuzzy Logic

, M.Sc. Thesis Sharif University of Technology Fattahi, Javad (Author) ; Khayyat, Amir (Supervisor)

Abstract

This thesis contributes two separate predictive direct torque control methods; based on hysteresis and fuzzy logic for Brushless Doubly Fed Induction Machine (BDFM). Initially Chapter 1, focuses on BDFM history and concept of this machine and after that a short review about the development of BDFM and the Field Oriented Control will be studied. Chapter 2 introduces the d-q-0 state transformation matrix, dynamic equation of BDFM and represents its steady-state equivalent. Furthermore, in this chapter the bond graph model of BDFM is studied and via distinguishing all energy ports the bond graph model of this motor is introduced and validated, finally the result of this model is compared with...

AdS3/CFT2 In The Presence of N=1 Supergravity

, M.Sc. Thesis Sharif University of Technology Fattahi, Mohammad (Author) ; Rouhani, Shahin (Supervisor)

Abstract

Brown and Henneaux showed that asymptotic symmetries of asymptotically form a conformal group in two dimensions [1]. Also they could derive classical central charge of theory. Fourteen years later, Maldacena, conjectured that this Holographic correspondence could be true for a specific theory a simplified chromodynamics in the boundary of ), this holographic theory attracted physicist communitee's attention. Many physicists tried to make this conjecture more precise. It is worth to say that, no example of holographic correspondence has been completely proven, till now, Because of the difficulty of the calculation. However these days we consider Madacena conjectrure in any arbitrary...

Identifying the risks of Iranian Knowledge BasedFirms Using Fault Tree Analysis (FTA)

, M.Sc. Thesis Sharif University of Technology Sarhadi, Maryam (Author) ; Fattahi, Omid (Supervisor)

Abstract

Knowledge Based Firms are considered to be important for the economic development of a country in regards to both employment growth and innovative activity. The latter is believed to contribute significantly to the increase in productivity and therefore the competitiveness of Iran’s economy. This study contributes to the above literature by investigating the factors that are believed to treat the growth of such firms in Iran. The purpose of this study is to identify functional risks of vital signs monitors via Fault Tree Analysis (FTA) method to use as a guide for manufacturers to identify and control hazards. Therefore, 30 knowledge based firms were selected as sample. Then, based on a...

A Meta Heuristic Approach for Design of a Network System in Mass Customization

, M.Sc. Thesis Sharif University of Technology Puresmaili, Ehsan (Author) ; Fattahi, Omid (Supervisor)

Abstract

This study discusses about mass customization and optimization of supply network in which both goal considering to set the flow of raw material and final product to satisfy the customer demand. The mass customization is more important concept in this study, so that this goal is placed to the first objective. In this research, the model which contained both goal is presented. The model focus on mass customization and try to satisfy various products demand, which constitute 3 kind of speed demands. Each product can satisfy in 3 way: fast, normal, slow.In the first model the new approach present in which the speed affects all of supplying, manufacturing and distributing system. The system try...

Exploring of Influence of Boron on Acidity of Organic Functional Groups by DFT Calculation

, M.Sc. Thesis Sharif University of Technology Mehrpajouh, Sima (Author) ; Fattahi, Alireza (Supervisor)

Abstract

Acidity values of some compound (e.g., alkanes, alcohols, carboxylic acids and amines) with or without boron substitute have been studied theoretically to evaluate the influence of boron on acidity of organic functional groups. We have derived the unoccupied reactive orbital that show the maximum localization on the boron pπ atomic orbital overlapping with the lone-pair orbital of an electron donor. Localization of unoccupied reactive orbital on the boron pπ atomic and the polarizability of the boron center are two factors which affect acidity values of functional groups. Conformational searching was performed using MM (Molecular Mechanics). The most important conformations were optimized at...

, M.Sc. Thesis Sharif University of Technology Eiravani, Hossaen (Author) ; Fattahi, Alireza (Supervisor)

Abstract

It is believed that intramolecular hydrogen bonding and also conjugation can affect the acidity power of organic molecules. But simultaneous effects of intramolecular hydrogen bonding and conjugation have not investigated systematically yet. In this project, we choose Ascorbic acid as a basic structure. Then we have changed its structure conveniently, and have explored the roles of hydrogen bonding and conjugation on the acidity of this molecule by using B3LYP functional with the 6-311++G(d,p) basis set. After that we similarly investigate these effects on the acidity of three different systems, including enols, enamines and alcohols. In this project we probe the effect of different hydrogen...

Computational Design of Novel Medicines as Inhibitors in Case of Cancer and Autoimmune Disease Treatment Based on Amino Acid and Sugar

, M.Sc. Thesis Sharif University of Technology Feghhi, Razieh (Author) ; Fattahi, Alireza (Supervisor)

Abstract

SHP2 has been reported as a critical non-receptor phosphatase enzyme that plays crucial roles in numerous disorders like cancer. The previous studies on this enzyme showed that inhibiting the action of the enzyme comes as a way of controlling enzyme activity. SHP099 was discovered as an Allosteric inhibitor of the enzyme with the most inhibitory effect among all of the studied compounds. In this study we aimed to design novel dipeptide-and sugar-based inhibitors for the allosteric binding site of this enzyme with in-silico studies including docking, molecular dynamic simulation, and free binding energy analysis. Our novel designed drugs possess enough binding properties, low toxicity, and...

Design of Novel Drugs Based on Tyrosine and Phenylalanine Amino Acids to Inhibit Cyclin-Dependent Kinases 2 (CDK2) Proteins Modeled on Flavopiridol Drug

, M.Sc. Thesis Sharif University of Technology Aghili, Farshad (Author) ; Fattahi, Alireza (Supervisor)

Abstract

Cyclin-dependent kinases 2 (CDK2) are one of the important proteins in cell cycle regulation and progression. In many human cancer cells, the activity of CDK2 kinases and their related subunits are deregulated, leading to tumor formation. Therefore, inhibition of this enzyme as an attractive therapeutic target can cause cancer cell death in glioblastoma and diffuse large B-cell lymphoma. Using new pharmaceutical structures based on sugar and amino acids is a new approach due to its greater efficacy and fewer side effects than old drugs. In this research, according to the structure of Flavopiridol as one of the CDK2 inhibitors, the active site of CDK2, and the structure of ATP molecule, 50...

Investigating the Effect of the Proposed CSF-1R Protein Inhibitor,with a Structure Containing Natural Biomolecules and based on the Approved Drug Vimseltinib

, M.Sc. Thesis Sharif University of Technology Ebtehaj, Pouria (Author) ; Fattahi, Alireza (Supervisor)

Abstract

Vimseltinib, a small molecule inhibitor, represents a promising avenue for combating cancers linked to macrophage-associated processes through its targeted action on the CSF1R tyrosine kinase receptor. CSF1R, a pivotal member of the tyrosine kinase receptor family, plays a crucial role in macrophage differentiation and function. This protein's significance is underscored in conditions such as tenosynovial giant cell tumors (TGCTs) and the presence of tumor-associated macrophages, wherein overproduction of CSF1 by neoplastic cells recruits CSF1R-dependent immune cells, fostering tumor expansion. The intricate interplay extends to tumor-associated macrophages, particularly the M2 subtype,...

Design of Drug Structures in Order to Inhibit Met, A Member of the Tyrosine Phosphatase Protein Family to Replace Existing Drugs

, M.Sc. Thesis Sharif University of Technology Zeinal, Mostafa (Author) ; Fattahi, Alireza (Supervisor)

Abstract

This project aims to design a novel structure that can inhibit the activitvation of the c-Met enzyme using amino acids and sugars building blocks. The c-Met enzyme is a receptor tyrosine kinase that plays a significant role in several biological activities such as cell proliferation, survival, and invasion. Abnormal activity of the enzyme is linked to the progression of various types of cancer, including breast, lung, liver, and stomach cancer. The proposed sugar amino acid conjugate structures is expected to increase stability amino acids and dipeptides in the physiological environment, improve membrane permeability via active transport mechanism, and reduce toxicity and side effects by...

Affinity Prediction of Natural Ligands and EGFR Protein

, M.Sc. Thesis Sharif University of Technology Sabounchi, Alireza (Author) ; Fattahi, Alireza (Supervisor)

Abstract

Measuring the binding affinity of a ligand for its target protein is regarded as a critical step in drug design and discovery, owing to its direct correlation with therapeutic efficacy. Conventional molecular docking methods, despite their widespread use in predicting binding affinity, often incur substantial computational and temporal costs, depending on the size and complexity of the protein and the small molecule. Consequently, recent studies have concentrated on employing machine learning and deep learning algorithms to predict both binding sites and affinities. The epidermal growth factor receptor (EGFR), a principal therapeutic target in various cancers, plays a pivotal role in the...

Theoretical and Computational Investigation of Quantum Plasmonic Properties of Nanocluster Dimers

, M.Sc. Thesis Sharif University of Technology Mahmoudi, Erfan (Author) ; Jamshidi, Zahra (Supervisor)

Abstract

In today's era, metal nanoparticles play an important role in technologies emerging from different sciences, such as chemistry, physics, optics, material science, due to their unique characteristics. In the development of nanooptics science, it can be said that metal nanoparticles play an important role. The ability of conductive electrons collective oscillation causes surface charge density fluctuations in nanoparticles, this phenomenon is known as surface plasmons. Surface plasmons are surprisingly coupled with light and cause the significant increase in the intensity of optical fields induced in nanoparticles. Therefore, with the presence of localized surface plasmons or plasmon...

Theoretical Investigation of Ab-initio MD Approach to Increase the Efficiency and Accuracy of VCD Spectrum Calculation

, M.Sc. Thesis Sharif University of Technology Hadi, Hossein (Author) ; Jamshidi, Zahra (Supervisor)

Abstract

Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic...