Optimization of Encapsulation of Probiotic Living Cells

, M.Sc. Thesis Sharif University of Technology Sajjadi Dehkordi, Sahar (Author) ; Alemzadeh, Iran (Supervisor)

Abstract

In the recent year, there has been a rising interest in producing functional foods containing encapsulated probiotic bacteria according to their perceived health benefits. Probiotics are feed and food supplements that beneficially affect the host’s health. The term “probiotic” includes a large range of microorganisms, mainly lactic acid bacteria. Because they can stay alive until the intestine and provide health beneficial effects like lowering cholesterol, improving lactose tolerance and preventing some cancers like colon cancer on the host health. It has been recommended that the viability of probiotics should be at least 107 CFU/ml of product at time of consumptions to provide selective...

Finite element modeling of trolling-mode AFM

, Article Ultramicroscopy ; Volume 189 , 2018 , Pages 24-38 ; 03043991 (ISSN) Sajjadi, M ; Nejat Pishkenari, H ; Vossoughi, G

Elsevier B.V 2018

Abstract

Trolling mode atomic force microscopy (TR-AFM) has overcome many imaging problems in liquid environments by considerably reducing the liquid-resonator interaction forces. The finite element model of the TR-AFM resonator considering the effects of fluid and nanoneedle flexibility is presented in this research, for the first time. The model is verified by ABAQUS software. The effect of installation angle of the microbeam relative to the horizon and the effect of fluid on the system behavior are investigated. Using the finite element model, frequency response curve of the system is obtained and validated around the frequency of the operating mode by the available experimental results, in air...

A Formal Semantics for CORBA Interface Definition Language

, M.Sc. Thesis Sharif University of Technology Sajjadi, Marjan (Author) ; Izadi, Mohammad (Supervisor)

Abstract

Common Object Request Broker Architecture (CORBA) is a standard for hybrid applications that is designed and supported by Object Management Group (OMG). This standard defines protocols and Relational Data Model Objects / Services which can be connected into heterogeneous software (written in different languages). So we can use CORBA to share the distributed object platform, without worrying about where they are located or who has designed them. CORBA can package the codes (in some programming languages) and add the packaging information, such as the ability to execute the codes and how to implement them. So this package or object code can execute some other programs or CORBA objects that...

Design and Synthesis of a Drug Delivery System Based on Mesoporous Bioactive Glass

, M.Sc. Thesis Sharif University of Technology Mirsafaie, Sahar Sadat (Author) ; Abdekhodaie, Mohammad Jafar (Supervisor)

Abstract

The aim of this research is to develop a smart mesoporous bioactive glass-based carrier for targeted drug delivery to cancer cells, particularly bone cancer cells. To achieve this, mesoporous bioactive glass nanoparticles were first synthesized, followed by surface modification with amine groups. To prevent premature drug release before reaching the target tissue and to introduce pH sensitivity, the nanoparticle pores were coated with oxidized hyaluronic acid via Schiff-base bonding with the amine groups on the surface. The use of hyaluronic acid facilitates active targeting of CD44 receptors, which are overexpressed on the surface of cancer cells compared to healthy cells. This process...

Complexity of density dependencies of thermal and internal pressure compared to that of total pressure

, Article Industrial and Engineering Chemistry Research ; Volume 52, Issue 23 , May , 2013 , Pages 8034-8045 ; 08885885 (ISSN) Sajjadi, S . H ; Parsafar, G ; Sharif University of Technology

2013

Abstract

A simple equation of state (EoS) has recently been introduced (J. Phys. Chem. B2009, 113, 11977-11987) as (Z - 1)v2 = e + f/ρ + gρ2, where Z ≡ pv/RT is the compressibility factor, v = 1/ρ is molar volume, and e, f, and g are temperature dependent parameters. This EoS has been found to be accurate for all types of nano and bulk solids and bulk fluids, in the entire temperature and pressure ranges for which experimental data are reported, except for the isotherms within 1 ≤ T r = T/Tc ≤ 1.1 for the spherical and near spherical species and for a wider temperature range for the cylindrical molecules. The aim of this work is to investigate the validity of a three-term expression similar to the...

Simulation of chatter vibrations in reaming

, Article ASME International Mechanical Engineering Congress and Exposition, IMECE 2007, Seattle, WA, 11 November 2007 through 15 November 2007 ; Volume 3 , 2008 , Pages 441-447 ; 0791842975 (ISBN); 9780791842973 (ISBN) Sajjadi, M ; Movahhedy, M. R ; Sharif University of Technology

2008

Abstract

A time domain approach is used to study the cutting conditions in reaming process that leads the system to regenerative chatter vibrations. The dynamic analysis of the system includes inertia of the tool, centripetal and Coriolis terms, damping and the first mode bending of reamer. A model of cutting forces proportional to chip cross sectional area and process damping proportional to cutting speed is considered. Numerical simulation based on the Euler integration scheme is carried out to obtain time domain solution of the equation. Despite linearization in force modelling, the model is nonlinear due to the change in the tool engagement area. Another nonlinearity included in the model jumping...

Simulation of chatter vibrations in reaming

, Article ASME 2007 International Mechanical Engineering Congress and Exposition, IMECE 2007, 11 November 2007 through 15 November 2007 ; Volume 3 , 2007 , Pages 441-447 ; 0791842975 (ISBN) Sajjadi, M ; Movahhedy, M. R ; Sharif University of Technology

American Society of Mechanical Engineers (ASME) 2007

Abstract

A time domain approach is used to study the cutting conditions in reaming process that leads the system to regenerative chatter vibrations. The dynamic analysis of the system includes inertia of the tool, centripetal and Coriolis terms, damping and the first mode bending of reamer. A model of cutting forces proportional to chip cross sectional area and process damping proportional to cutting speed is considered. Numerical simulation based on the Euler integration scheme is carried out to obtain time domain solution of the equation. Despite linearization in force modelling, the model is nonlinear due to the change in the tool engagement area. Another nonlinearity included in the model jumping...

Electrodeposition of Pt nanostructures and its Application as Glucose Sensor

, Ph.D. Dissertation Sharif University of Technology Mahshid, Sahar Sadat (Author) ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)

Abstract

The present work describes sensing application of modified Pt nanostructures towards detection of glucose. Modified Pt nanostructured electrodes were prepared using electrodeposition method such as chronoampermetry and potentiostatic pulse methods. The electrodeposition of Pt nanostructures was first studied by voltammetry and amperommetry techniques and then potentiostatic pulse method has been used to produce the alloyed structures of platinum. In this regard, the first electrode was proposed based on alloyed Pt/Ni nanowire arrays (NWAs) for the non-enzymatic detection of glucose. The Pt/Ni NWAs were prepared by pulse electrodeposition of Pt and Ni within a nano-pore polycarbonate (PC)...

Quantum Estimation of Open Systems Using Extended Cramer-Rao Bounds

, M.Sc. Thesis Sharif University of Technology Mehboudi, Mohammad (Author) ; Rezakhani, Ali (Supervisor) ; Alipour, Sahar (Co-Advisor)

Abstract

Any physical system is characterized with some set of quantities or parameters, knowing which, is equivalent to estimation of the system. Evaluating such parameters is usually done using tomography methods. An important question to ask, is how to increase the precision of measurement, being able to do some specific set of physical operations, say, measurement?
this question is more important in parameter estimation in quantum meanical systems. It has been shown that, quantum meanics causes a fundamental limit, on precision of estimating su parameters, escribed by the so called “antum Cramér-Rao bound”.We must note that almost all quantum meanical systems are interacting with the...

Social distancing in pedestrian dynamics and its effect on disease spreading

, Article Physical Review E ; Volume 104, Issue 1 , 2021 ; 24700045 (ISSN) Sajjadi, S ; Hashemi, A ; Ghanbarnejad, F ; Sharif University of Technology

American Physical Society 2021

Abstract

Nonpharmaceutical measures such as social distancing can play an important role in controlling the spread of an epidemic. In this paper, we use a mathematical model combining human mobility and disease spreading. For the mobility dynamics, we design an agent-based model consisting of pedestrian dynamics with a novel type of force to resemble social distancing in crowded sites. For the spreading dynamics, we consider the compartmental susceptible-exposed-infective (SEI) dynamics plus an indirect transmission with the footprints of the infectious pedestrians being the contagion factor. We show that the increase in the intensity of social distancing has a significant effect on the exposure...

Haptic Design for Steering Mechanism in a System for Remote Vehicle Driving

, M.Sc. Thesis Sharif University of Technology Sajjadi, Mohammad Reza (Author) ; Salarieh, Hassan (Supervisor)

Abstract

The purpose of this thesis is to design haptic control system for vehicle steering mechanism in a tele-driving system. Thus the subject is a developed subject in comparison with a steer by wire system. The difference is that in the steer by wire system, due to the lack of delay in sending and receiving data, possibility of instability is very low. This subject makes haptic control more difficult in vehicle tele-driving. Control of vehicle tele-driving steering system has been done by different bilateral control structures available in the literature. simulation results of the case that there is no delay in the transmission block suggest that used different control structures in order to...

Hardware Acceleration of Convolutional Neural Networks by Computational Prediction

, M.Sc. Thesis Sharif University of Technology Sajjadi, Pegahsadat (Author) ; Bayatsarmadi, Siavash (Supervisor)

Abstract

Recently, Convolutional neural networks (CNNs) are widely used in many artificial intelligence applications such as image processing, speech processing and robotics. The neural networks superior accuracy comes at the cost of high computational complexity. Recent studies show that these operations can be performed in parallel. Therefore, as graphic processing units (GPUs) offer the best performance in terms of computational power and throughput, they are widely used to implement and accelerate neural networks. Nevertheless, the high price and power consumption of these processors have resulted in drawing more attraction towards Field-Programmable Arrays (FPGAs). In order to improve resource...

Active Control of Vibrations Transmitted to the Human Body in the Vehicle and in the Presence of Uncertainties Using the Robust Control Method

, M.Sc. Thesis Sharif University of Technology Sajjadi, Amir Hossein (Author) ; Moradi, Hamed (Supervisor)

Abstract

With the advent of new technologies in everyday human life, issues related to the use of vehicles have become crucial subjects of investigation. In this context, vibrations transmitted from the vehicle to the human body, especially in terms of long-term health effects, have garnered special attention and significance. The main objective of this research is to develop a control system for the active control of vibrations transmitted to the human body. To achieve this goal, a 5-DOF model of the human body has been employed as the study system. Considering the uncertainties in the parameters and dynamics of this model, H∞ and µ-synthesis methods have been utilized for robust control design. The...

Image acquisition for trolling-mode atomic force microscopy based on dynamical equations of motion

, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; 2020 Sajjadi, M ; Nejat Pishkenari, H ; Vossoughi, G ; Sharif University of Technology

SAGE Publications Ltd 2020

Abstract

Trolling mode atomic force microscopy (TR-AFM) can considerably reduce the liquid-resonator interaction forces, and hence, has overcome many imaging problems in liquid environments. This mode increases the quality factor (QF) significantly compared with the conventional AFM operation in liquid; therefore, the duration to reach the steady-state periodic motion of the oscillating probe is relatively high. As a result, utilizing conventional imaging techniques, which are based on measuring the amplitude and phase, are significantly slower when compared to our proposed method. This research presents a high-speed scanning technique based on an estimation law to obtain the topography of various...

Impact of temporal correlations on high risk outbreaks of independent and cooperative SIR dynamics

, Article PLoS ONE ; Volume 16, Issue 7 July , 2021 ; 19326203 (ISSN) Sajjadi, S ; Ejtehadi, M. R ; Ghanbarnejad, F ; Sharif University of Technology

Public Library of Science 2021

Abstract

We first propose a quantitative approach to detect high risk outbreaks of independent and coinfective SIR dynamics on three empirical networks: A school, a conference and a hospital contact network. This measurement is based on the k-means clustering method and identifies proper samples for calculating the mean outbreak size and the outbreak probability. Then we systematically study the impact of different temporal correlations on high risk outbreaks over the original and differently shuffled counterparts of each network. We observe that, on the one hand, in the coinfection process, randomization of the sequence of the events increases the mean outbreak size of high-risk cases. On the other...

Image acquisition for trolling-mode atomic force microscopy based on dynamical equations of motion

, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 235, Issue 18 , 2021 , Pages 3654-3677 ; 09544062 (ISSN) Sajjadi, M ; Pishkenari, H. N ; Vossoughi, G ; Sharif University of Technology

SAGE Publications Ltd 2021

Abstract

Trolling mode atomic force microscopy (TR-AFM) can considerably reduce the liquid-resonator interaction forces, and hence, has overcome many imaging problems in liquid environments. This mode increases the quality factor (QF) significantly compared with the conventional AFM operation in liquid; therefore, the duration to reach the steady-state periodic motion of the oscillating probe is relatively high. As a result, utilizing conventional imaging techniques, which are based on measuring the amplitude and phase, are significantly slower when compared to our proposed method. This research presents a high-speed scanning technique based on an estimation law to obtain the topography of various...

High temperature tensile behaviour of the Ni-base superalloy GTD-111

, Article Canadian Metallurgical Quarterly ; Volume 42, Issue 4 , 2003 , Pages 489-494 ; 00084433 (ISSN) Sajjadi, S. A ; Nategh, S ; Isac, M ; Sharif University of Technology

Metallurgical Society of CIM 2003

Abstract

The Ni-based superalloy GTD-111 is employed in high power stationary gas turbines because of its high temperature strength and oxidation resistance. The temperature dependence of the tensile behaviour of GTD-111 has been studied by tensile tests with a constant strain rate of 10-4s-1 over the temperature range of 25-900°C. The results showed an abnormal variation in tensile properties with increasing temperature. The yield strength decreased slightly with temperatures up to about 650°C and then increased between 650 and 750°C. Above 750°C, a rapid decrease in the yield strength was found. The tensile strength showed a similar behaviour except for its maximum, which occurred at 650°C....

Imaging performance of trolling mode atomic force microscopy: investigation of effective parameters

, Article Archive of Applied Mechanics ; Volume 92, Issue 5 , 2022 , Pages 1551-1570 ; 09391533 (ISSN) Sajjadi, M ; Chahari, M ; Nejat Pishkenari, H ; Sharif University of Technology

Springer Science and Business Media Deutschland GmbH 2022

Abstract

In this study, we investigate the limitations and influence of various factors on the performance of trolling mode atomic force microscopy (TR-AFM). For this purpose, at first, based on the governing equations of motion and using a conventional control method, a simulation tool capable of correctly simulating the imaging procedure in TR-AFM is developed. Then based on the developed simulation tool, imaging of different surfaces is performed, and the effect of different factors on the image quality is analyzed. The flexibility of nanoneedle in TR-AFM has unpredictable effects on dynamics of system as well as imaging performance. One problem in imaging is due to coexistence of two stable...

Hour-ahead demand forecasting in smart grid using support vector regression (SVR)

, Article International Transactions on Electrical Energy Systems ; Vol. 24, issue. 12 , 2014 , p. 1650-1663 Fattaheian-Dehkordi, S ; Fereidunian A ; Gholami-Dehkordi H ; Lesani H ; Sharif University of Technology

2014

Abstract

Demand forecasting plays an important role as a decision support tool in power system management, especially in smart grid and liberalized power market. In this paper, a demand forecasting method is presented by using support vector regression (SVR). The proposed method is applied to practical hourly data of the Greater Tehran Electricity Distribution Company. The SVR parameters are selected by using a grid optimization process and an investigation on different kernel functions. Moreover, correlation analysis is used to find exogenous variables. Acceptable accuracy of load prediction is shown by comparing the result of SVR model to that of the artificial neural networks and the actual data,...

On the nonlinear dynamics of trolling-mode AFM: analytical solution using multiple time scales method

, Article Journal of Sound and Vibration ; Volume 423 , 9 June , 2018 , Pages 263-286 ; 0022460X (ISSN) Sajjadi, M. R ; Nejat Pishkenari, H ; Vossoughi, G ; Sharif University of Technology

Academic Press 2018

Abstract

Trolling mode atomic force microscopy (TR-AFM) has resolved many imaging problems by a considerable reduction of the liquid-resonator interaction forces in liquid environments. The present study develops a nonlinear model of the meniscus force exerted to the nanoneedle of TR-AFM and presents an analytical solution to the distributed-parameter model of TR-AFM resonator utilizing multiple time scales (MTS) method. Based on the developed analytical solution, the frequency-response curves of the resonator operation in air and liquid (for different penetration length of the nanoneedle) are obtained. The closed-form analytical solution and the frequency-response curves are validated by the...