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parsafar--mohammad-habib
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A Physiological model-based study of flow-mediated dilation in peripheral arteries using finger photoplethysmogram signal
, Article 2017 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) ; Zahedi, E ; Vosoughi Vahdat, B ; Sharif University of Technology
2018
Abstract
Flow-mediated dilation measurement in the brachial artery using ultrasound imaging (FMD-US) is a common noninvasive procedure for endothelial function evaluation in the peripheral arteries. As FMD-US is operator-dependent and involves onerous equipment, its use has been mostly confined to research settings. In this paper, we propose to use the more accessible finger photoplethysmogram signal in conjunction with the FMD test (FMD-PPG) as a surrogate method. To this end, a tube-load physiological model of the upper arterial path in the arm is developed. Signals acquired from young and elderly subjects (N=20) are then investigated using model parameter estimation by the genetic algorithm. Our...
Superhydrophobic Materials as Nanosorbents for Extraction Methodologies
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
In the first work, a superhydrophobic polystyrene hollow fiber (PS–HF) was synthesized by electrospinning and used in microextraction of trazine herbicides from aquatic media followed by gas chromatography mass spectrometric (GC–MS) determination. Effects of different parameters influencing the extraction efficiency including the solvent extraction and its amount, the desorbing solvent and its amount, extraction time and ionic strength were optimized. The characteristic properties of the hollow fiber were studied by scanning electron microscopy (SEM). The limits of detection and quantification of the method under optimized condition were 2 and 6 ng L-1, respectively. The relative standard...
Autonomous Orbit and Attitude Estimation of Satellite Using Star Sensor and Earth Sensor
, M.Sc. Thesis Sharif University of Technology ; Ghanbarpour Asl, Habib (Supervisor)
Abstract
In this Thesis, attitude and orbit of a satellite is estimated using a star sensor and an earth sensor. An algorithm has been developed to estimate satellite attitude and orbit that can be implement on a satellite as strap-down hardware. This system has an uncomplicated implementation compared with platform based systems. That mentioned algorithm estimates satellite orbit by using identified star vectors via star sensor and identified earth vector via earth sensor simultaneously. It also knows the stars vectors according to Star Catalog. Attitude estimation is also executed using both star and earth sensor. It has to be said that an Unscented Kalman Filter synthesize both sensors output data...
Modeling the Relationship between Central Aortic Pressure and Radial Photoplethysmogram in Flow-mediated Dilation Test
, Ph.D. Dissertation Sharif University of Technology ; Vosughi Vahdat, Bijan (Supervisor) ; Zahedi, Edmond (Supervisor)
Abstract
According to the World Health Organization, about 35% of deaths worldwide are due to cardiovascular diseases, therefore the evaluation of vascular endothelial function has great prognostic and diagnostic value for cardiovascular diseases. The conventional noninvasive method for endothelial function evaluation is the measurement of flow-mediated dilation in brachial artery using ultrasound imaging (FMD-US). As the accuracy of FMD-US depends on the operator's skill and the resolution of the ultrasound images, this method has not been adopted. In this work, we propose to use a low cost, easily-accessible surrogate signal, the photoplethysmogram (PPG) to implement the FMD test. Whereas previous...
Highly Sensitive Detection of Captopril by Fluorescein-5-Isothiocyanate-Modified Gold Nanoparticles Based on FRET& Antioxidant Activity Assay in Iranian Tea Using the Generation and Growth of Metalic Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor) ; Hormozi Nezhad, Mohammad Reza (Supervisor)
Abstract
The research of this work was divided into two parts. First, A novel fuorescence sensor based on fluorescence resonance energy transfer for the determination of captopril was developed. FITC molecules that are highly fluorescent in alkaline solution fluoresce weakly when they are adsorbed onto AuNP surfaces (based on affinity of AuNPs and isothiocyanate group on FITC) as a result of fluorescence resonance energy transfer. In the presence of captopril, FITC molecules are released from the AuNP surface in order to stronger affinity to AuNPs surface than FITC molecule (in order to thiol group in captopril) so the florescence intensity of FITC restore. This phenomenon was used for quantitative...
Study Elongation of a Single Strend DNA on the Surface Under Potential Using Monte Carlo Simulation
, M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor) ; Tafazzoli, Mohsen (Supervisor) ; Ejtehadi, Mohammad Reza (Co-Advisor)
Abstract
In this project, the behavior of single strand DNA (ssDNA) that is end-tethred to surface (surface is covered with an layer of mercaptohexane ) through the Monte Carlo simulation has been investigated. To understand this behavior, a ssDNA has been studied through freely jointed chain (FJC) model with electrostatic, base paring, and base-pair stacking interaction. The concentration of sodium chloride salt in solution is 1 mM and the applied surface potential is -1.5 - +0.25 V. Computational results show that the ssDNA chain can have the following configurations: 1) “very closed”, 2) “closed”, and 3) “open” that considering the amount of energy, the mentioned configurations can be compared...
Nonlinear Filters Applied to Tightly Coupled Integration of INS/GPS/PL for Precise Navigation in Automatic Landing of UAVs
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor) ; Ghanbarpour Asl, Habib (Supervisor)
Abstract
One of the most dangerous phases of the flight is landing. Newly automatic landing is noticed. The vital element in an automatic landing system is navigation system. In this document, a PL/INS/DGPS auto landing system is introduced.In a PL based navigation system, accuracy is highly under the influence of relative geometry between PLs position and flight path. Therefore, it is necessary to locate PLs on the best position. An optimization is used to find PLs best configuration that increases the navigation performance. Tightly coupling of INS and GPS/PL is preferred, because some problems lead to GPS satellite signal unavailability
Theoretical Study of Metallochlorophylls of Forth Period Elements in Periodic Table
, M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor)
Abstract
In this study, some properties of metallochlorophylls - compounds produced by replacing Mg2+ in tetrapyrrolic ring of chlorophyll b with divalent ions – of the forth period transit elements of the periodic table have been investigated. Using DFT/B3LYP method and DGDZVP basis set, structures of these compounds were optimized and the energy of electronic levels, Gibbs free energy of formation of complex, contribution of atomic orbitals to formation of molecular orbitals and partial charges in these molecules were computed. The results show that some properties of these complexes cannot be justified by the common theories of complexes. Among these properties is the negligible effect of...
Investigation of the Performance and Mechanism of Permeation through Biological Membranes
, Ph.D. Dissertation Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor)
Abstract
Ion channels are present in all cell membranes which are the important part of the performances in regulating the flow across the membrane as well as the signaling. We have investigated the water permeation through carbon nanotube (CNT) membranes as a model for the synthetic ion channels, i.e. peptide nanotube channels (PNCs). The effect of different charge configured CNTs which tailored based on these ion channels on the water permeation has been studied. In addition, the temperature dependence of the permeation using statistical models such as continuous time random walk model (CTRW) via molecular dynamics simulation has been investigated. We have found that there is a jump in the...
User Privacy in Enterprise Mobile Management
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
The expansion of technology and the increasing use of mobile devices and smartphones have aected various aspects of personal and social life. These include the use of personal mobile devices in enterprise environments called BYODs have a number of positive and negative eects. On the one hand, it would be more cost-eective for an organization or business environment for users to use their own devices, but on the other hand, it poses numerous security and information challenges that are important to manage. These include disrupting the user’s privacy or disseminating organization information to personal devices and thus violating the organization’s security policies. In this study, a model is...
Extension of the dense system equation of state to electrolyte solutions
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 26, Issue 1 , 2007 , Pages 17-33 ; 10219986 (ISSN) ; Panahi, A ; Sharif University of Technology
2007
Abstract
In this work we have applied the Dense System Equation of State (DSEOS) to electrolyte solutions. We have found that this equation of state can predict the density of electrolyte solutions very accurately. It has been tested for different electrolytes solutions at different temperatures and compositions. A hypothetical binary model has been applied to find the dependencies of parameters of this equation of state on solution temperature and composition. Using such a simple model the heat capacity of NaCl solution was calculated for which the absolute percent deviation is less than 2 %. The DSEOS is tested for the following electrolytes: Na2SO4, MgCl2, MgSO4, KCl, NaCl, and NaBr. We found that...
Vital role of water in longevity of SARS-CoV-2 and enhancing its binding with human cells
, Article Journal of the Iranian Chemical Society ; 2021 ; 1735207X (ISSN) ; Reddy, V ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Based on our present knowledge on SARS-CoV-2 virus, which is collectively summarized in this work, it is shown that water plays a crucial role in stabilizing the virus, in such a way that its viability may reduce from a few days to a few seconds in the absence of water layer. Water not only provides a protective shell for the virus in which it is enveloped, but enhances its binding with the human cell. Therefore, one may conclude that the dehydration of the hydrated virus makes it much more vulnerable, due to the fact that if it is exposed to many chemicals it will be deactivated; even by particles in air, such as ozone, singlet oxygen and pollutants. Thermodynamically, the dehydration may...
Vital role of water in longevity of SARS-CoV-2 and enhancing its binding with human cells
, Article Journal of the Iranian Chemical Society ; Volume 19, Issue 1 , 2022 , Pages 203-210 ; 1735207X (ISSN) ; Reddy, V ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Based on our present knowledge on SARS-CoV-2 virus, which is collectively summarized in this work, it is shown that water plays a crucial role in stabilizing the virus, in such a way that its viability may reduce from a few days to a few seconds in the absence of water layer. Water not only provides a protective shell for the virus in which it is enveloped, but enhances its binding with the human cell. Therefore, one may conclude that the dehydration of the hydrated virus makes it much more vulnerable, due to the fact that if it is exposed to many chemicals it will be deactivated; even by particles in air, such as ozone, singlet oxygen and pollutants. Thermodynamically, the dehydration may...
Extension of linear isotherm regularity to long chain alkanes
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 22, Issue 2 , 2003 , Pages 1-8 ; 10219986 (ISSN) ; Kalantar, Z ; Sharif University of Technology
2003
Abstract
In this work, we consider each normal alkane as a hypothetical mixture of methyl and methylene groups, in which the interaction potential of each pair is assumed to be the average effective pair potential. Then, the LIR equation of state (EOS) is extended for such a hypothetical mixture. Also, three basic compounds, namely, propane, n-butane and cyclohexane, are used to obtain the contribution of each carbonic group in the EOS parameters. Using the calculated EOS parameters along with the modified EOS, the density of n-alkanes and their mixtures at different pressures and temperatures are calculated. The average percentage error in density is found to be less than 1.5% for both the pure...
Calculation of Effective Pair Potential Function by Using Pressure−Temperature−Volume Data
, M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor)
Abstract
In this work, by considering the medium effects and adding the long−range interactions to the isolated pair potential, the concept of the extended effective pair potential of the Lennard−Jones (12, 6, 3) has been purposed for dense systems. Due to lack of any information regarding the parameters of this potential for any fluid, the purpose of this work is to introduce a new method to calculate these parameters using experimental pVT data. Since the extended potential of Lennard− Jones (12, 6, 3) is a general function based on which that an equation of state can be derived (equation of state III) predicts many properties of dense systems that no deviation is observed. Also it doesn’t have...
Dependence of Surface Tension on Temperature and Density in the Interface of Liquid & Vapour
, M.Sc. Thesis Sharif University of Technology ; Parsafar, GholamAbbas (Supervisor)
Abstract
In this thesis dependency of surface tension ( ) on temperature (T ) and density (?), for spherical and nearly spherical fluids like argon has been investigated, using an effective Lennard – Jones (12,6) potential along with a new model according to which half of surface molecules are assumed to be in the liquid phase and the other half in the vapor phase, far from the critical point. The obtained result may be expressed as ? ? ? ( The 2 2= +C D C and D parameters are independent of T and ?). Such an investigation has also been done for many fluids, but by using the extended Lennard – Jones (12, 6, 3) function as the effective pair...
Calculation of the transport properties of dense fluids using modified Enskog theory and an appropriate equation of state
, Article Fluid Phase Equilibria ; Volume 253, Issue 2 , 2007 , Pages 108-117 ; 03783812 (ISSN) ; Kalantar, Z ; Sharif University of Technology
2007
Abstract
In this work, a new method based on the modified Enskog theory (MET) is presented for calculation of transport properties at high densities (ρ > ρc). The main limitation of using the MET is lack of experimental data for co-volume, b0. We have substituted b0 from hard sphere (HS) theory and zero density transport properties from the kinetic theory of gases for HS in the MET expression, because of the fact that dense fluids behave more and less like a HS fluid. As a result, a simple linear expression for the self diffusion (D) and quadratic expressions for viscosity (η) and thermal conductivity (λ) coefficients have been obtained in terms of Y at high densities (ρ > ρc), where Y = (T (∂ p / ∂...
Effect of the attraction range of pair potential on the thermodynamic properties of fluids
, Article Scientia Iranica ; Volume 14, Issue 2 , 2007 , Pages 118-125 ; 10263098 (ISSN) ; Ahadzadeh, I ; Sharif University of Technology
Sharif University of Technology
2007
Abstract
Recently, a new potential model has been proposed for the intermolecular interactions of model pure fluids and it was shown that the derived Equation Of State (EOS), based on this potential, can properly predict the thermodynamic properties of these.fluids. In addition to simplicity and, to some extent, the realistic form, this potential has a parameter (α) which controls the range of the attraction tail. In the first part of this study, the proposed potential and derived EOS are extended to binary mixtures of model fluids. In a similar manner to that of the pure fluids, the results obtained are consistent with the data available from simulation studies. In the second part, after...
Deriving analytical expressions for the ideal curves and using the curves to obtain the temperature dependence of equation-of-state parameters
, Article International Journal of Thermophysics ; Volume 27, Issue 5 , 2006 , Pages 1564-1589 ; 0195928X (ISSN) ; Izanloo, C ; Sharif University of Technology
2006
Abstract
Different equations of state (EOSs) have been used to obtain analytical expressions for the ideal curves, namely, the Joule-Thomson inversion curve (JTIC), Boyle curve (BC), and Joule inversion curve (JIC). The selected EOSs are the Redlich-Kwong (RK), Soave-Redlich-Kwong (SRK), Deiters, linear isotherm regularity (LIR), modified LIR (MLIR), dense system equation of state (DSEOS), and van der Waals (vdW). Analytical expressions have been obtained for the JTIC and BC only by using the LIR, MLIR, and vdW equations of state. The expression obtained using the LIR is the simplest. The experimental data for the JTIC and the calculated points from the empirical EOSs for the BC are well fitted into...
Modification of a new potential model used for calculation of the second virial coefficient and zero density transport properties
, Article Molecular Physics ; Volume 104, Issue 20-21 , 2006 , Pages 3269-3280 ; 00268976 (ISSN) ; Shokouhi, M ; Sharif University of Technology
2006
Abstract
A new hard-core potential model was recently used to calculate thermodynamic properties of some model fluids, including equilibrium properties, such as compressibility factor and internal energy. A Lennard-Jones (LJ) like potential has been used to modify the repulsive part of the potential. The modified potential contains five parameters, namely, R, and HS. The parameter is the tail of the attractive branch whose value changes from zero to one. In this work, we have chosen = 1 to make the potential continuous at separation r = R, where the parameter R is the well width. R lies in the range 1.2 to 2.5, and R = 1.3 was found to be the best value for all real gases studied. The parameter is...