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Determination of Protein Absorption Profile at the Surface of Biocompatible Superparamagnetic Iron Oxide Nanoparticles using Gel Electrophoresis
, M.Sc. Thesis Sharif University of Technology ; Hormozi Nezhad, Mohammad Reza (Supervisor) ; Mahmoudi, Morteza (Supervisor)
Abstract
Superparamagnetic Iron Oxide NPs (SPIONs) because of their multi-task capabilities (e.g. magnetic labeling, cell isolation, hyperthermiaand controlled drug release) have been recognized as one of the most promising NPs for theranosis applications.When NPs come in contact with a biological medium, the surfaces of them are covered by biomolecules (e.g., proteins, natural organic materials, and enzymes). Therefore, what a biological entity, such as cells, tissues, and organs, sees when interacting with NPs is different original pristine surface of the NPs and actually is hard protein corona. Shape of NPs has a great impact on proteins adsorb onto its surface and consequently on the way that...
Investigating the Effects of Specimen Size and Dimensions Ratio on Compressive Strength of Concrete
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Mohammad Tagi (Supervisor)
Abstract
Concrete is one of the most widely used building materials. Compressive strength of concrete is the most important property in designing reinforced concrete structures. Compressive strength test should be carried out on specimens with standard dimensions. In practice, dimensions of structural elements could be different from the dimensions of standard specimen. The dimensions’ ratio influences the strength of concrete specimen and the coefficient of strength variation. In the present study it is tried to obtain a meaningful relationship between size and strength based on the results of the tests on the specimens with different dimension ratios. Specimens examined in this study are C25 grade...
Investigation of Effect of the Initial Bubble Shape on Rising Bubble Behaviour
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor)
Abstract
In this experimental work terminal velocity, velocity profile and aspect ratio of bubble with 1.49 mm diameter which ascend in pure water and infected by surfactant nonionic C10DMPO and surfactant ionic SDS in regime that surface tension is dominant, have been considered. Observations showed that with respect to entering nozzle, bubbles with this diameter have two initial stable shape; spherical and extended form on surface for horizontal needle and vertical nozzle. Results are (1) Bubbles with initial spherical shape had lower terminal velocity and higher aspect ratio with respect to bubbles with initial extended form, (2) Spherical bubble had aspect ratio about 1 at whole bubble column...
Application of Experimental Design for Synthesis and Controlling Aspect Ratio of Metallic Nanorods
, M.Sc. Thesis Sharif University of Technology ; Jalali-Heravi, Mehdi (Supervisor) ; ormozi Nezhad, Mohammad Reza (Supervisor)
Abstract
Aspect ratio dependant optical properties of silver and gold nanorods is responsible for great attention toward controlling the aspect ratio of this class of the nanostructure for their application in variety of area, such as medical diagnosis, drug delivery, biosensing and treatment. In this research, gold and silver nanorods have been synthesized using chemical reducation and growth based on seed mediated method, which is the newest and one of the best methods with less difficulty for producing silver and gold nanorods. Absorption of the visible light by gold and silver nanorods results in appearing the longitudinal and transverse Plasmon bands in their absorption spectra which is related...
Non-Equilibrium Interfacial Behavior of Dynamic Interfaces in Presence of Surfactants and Nanoparticles; Experimental and Computational Fluid Dynamic Investigations
, Ph.D. Dissertation Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Lotfi, Marzieh (Supervisor)
Abstract
The present study has been performed for better understanding about the dynamic behavior of fluid interfaces in presence of surfactants, nanoparticles and their interactions in gas-liquid dispersion systems. One of the main purposes of this work is to investigate the influence of surface modified nanoparticles on the dynamic behavior of gas-liquid interfaces. For this purpose, the rising bubble experiment was used as one of the most conventional procedures. Local velocities of bubbles rising in nanoparticle solutions were determined experimentally. Influences of silica nanoparticles which were modified via three approaches were investigated in these experiments. Heat treatment was applied to...
Evaluating of Geometric Factors Effects on Seakeeping Performance of HARTH Vessels
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeed (Supervisor)
Abstract
Performing research and development in the field of modern vessel types which serve several functions is considerably necessary because of their importance and rapid development. HARTH vessel is considered one of the important ships which has been recently attracted much attention from the world. In this respect, a full investigation of its performance could make a big contribution to its optimum design and appropriate exploitation.“HARTH” ship is the abbreviation for “High Aspect Ratio Twin Hull” is included in the catamaran vessel category with a high aspect ratio with respect to their underwater cross-section’s ratio of length to width.A host of crucial issues should be considered for...
Study of Biomolecules Imaging Using Molecular Dynamics Simulations
, Article Nano ; Volume 10, Issue 7 , October , 2015 ; 17932920 (ISSN) ; Nejat Pishkenari, H ; Moosavi, A ; Meghdari, A ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2015
Abstract
The process of imaging a biomolecule by atomic force microscope (AFM) is modeled using molecular dynamics (MD) simulations. Since the large normal force exerted by the tip on the biosample in contact and tapping modes may damage the sample structure and produce irreversible deformation, the noncontact mode of AFM (NC-AFM) is employed as the operating mode. The biosample is scanned using a carbon nanotube (CNT) as the AFM probe. CNTs because of their small diameter, high aspect ratio and high mechanical resistance attract many attentions for imaging purposes. The tip-sample interaction is simulated by the MD method. The protein, which has been considered as the biomolecule, is ubiquitin and a...
Size-dependent strain gradient-based thermoelastic damping in micro-beams utilizing a generalized thermoelasticity theory
, Article International Journal of Applied Mechanics ; Volume 11, Issue 1 , 2019 ; 17588251 (ISSN) ; Asghari, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2019
Abstract
The small-scale effects on the thermoelastic damping (TED) in Euler-Bernoulli micro-beams is investigated in this study. To this purpose, by utilizing the strain gradient theory (SGT) and the dual-phase-lag (DPL) heat conduction model, the coupled equations of motion and heat conduction are derived. By solving these equations simultaneously and using the Galerkin method, the real and imaginary parts of the frequency and the amount of TED in thin micro-beams are obtained. The results predicted by SGT are compared with those given by the modified couple stress theory (MCST) and the classical continuum theory. In addition, TED is calculated on the basis of energy dissipation approach which...
Size-dependent strain gradient-based thermoelastic damping in micro-beams utilizing a generalized thermoelasticity theory
, Article International Journal of Applied Mechanics ; Volume 11, Issue 1 , 2019 ; 17588251 (ISSN) ; Asghari, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2019
Abstract
The small-scale effects on the thermoelastic damping (TED) in Euler-Bernoulli micro-beams is investigated in this study. To this purpose, by utilizing the strain gradient theory (SGT) and the dual-phase-lag (DPL) heat conduction model, the coupled equations of motion and heat conduction are derived. By solving these equations simultaneously and using the Galerkin method, the real and imaginary parts of the frequency and the amount of TED in thin micro-beams are obtained. The results predicted by SGT are compared with those given by the modified couple stress theory (MCST) and the classical continuum theory. In addition, TED is calculated on the basis of energy dissipation approach which...
A comprehensive study on the critical ventilation velocity in tunnels with different geometries
, Article International Journal of Ventilation ; Volume 14, Issue 3 , Mar , 2015 , Pages 303-320 ; 14733315 (ISSN) ; Afshin, H ; Farhanieh, B ; Sharif University of Technology
VEETECH Ltd
2015
Abstract
Longitudinal ventilation is a common technique for smoke management during a fire accident within tunnels. In this paper, fire and smoke movement behaviour in longitudinally ventilated tunnels is investigated focusing on critical ventilation velocity. Firstly, critical velocity (VC) is evaluated for different heat release rates and results are compared and verified with model scale experimental data. Secondly, two fire scenarios inside tunnels with different cross sections are arranged and the reliability of some existing correlations for VC is explored. Results illustrate that using a combined geometric scale rather than the traditional single length-scale ones results in better estimation...
A numerical study of reactive pollutant dispersion in street canyons with green roofs
, Article Building Simulation ; Volume 11, Issue 1 , February , 2018 , Pages 125-138 ; 19963599 (ISSN) ; Afshin, H ; Farhanieh, B ; Sharif University of Technology
Tsinghua University Press
2018
Abstract
Roof greening is a new technique for improvement of outdoor thermal environment which influences air quality through its impacts on thermal and flow field. In order to examine effects of green roofs on reactive pollutant dispersion within urban street canyons, a computational fluid dynamics (CFD) model was employed which contained NO-NO2-O3 photochemistry and energy balance models. Simulations were performed for street canyons with different aspect ratios (H/W) of 0.5, 1.0, and 2.0 such that leaf area density (LAD) of green roofs changed. It was found that roof greening led distribution of pollutants to alter for H/W = 0.5 and 1.0 cases in such a manner that their averaged concentrations had...
Microstructural investigation of semisolid aluminum a356 alloy prepared by the combination of electromagnetic stirring and gas induction
, Article 15th International conference on Semi-Solid Processing of Alloys and Composites, S2P 2018, 22 October 2018 through 24 October 2018 ; Volume 285 SSP , 2019 , Pages 290-295 ; 16629779 (ISSN); 9783035713732 (ISBN) ; Yekani, F ; Aashuri, H ; Sharif University of Technology
Trans Tech Publications Ltd
2019
Abstract
A three phase electromagnetic stirrer was used to agitate aluminum A356 slurry and a dry and oxygen free argon gas was introduced in to the slurry by a porous graphite core at a same time. The prepared semi-solid slurry was then transferred into a metallic mold and was compacted by a drop weight. Results demonstrated a favorable increase in shape factor, decrease in aspect ratio and average diameter size at different intensities of stirring. The intensity of stirring was changed by altering the current passed through the magnetic coil and also bubbling intensity via the porous graphite diffuser. Different time intervals for electromagnetic stirring and gas induction were applied. Agitating...
Analytical determination of shear correction factor for Timoshenko beam model
, Article Steel and Composite Structures ; Volume 29, Issue 4 , 2018 , Pages 483-491 ; 12299367 (ISSN) ; Faghidian, S. A ; Shodja, H. M ; Sharif University of Technology
Techno Press
2018
Abstract
Timoshenko beam model is widely exploited in the literature to examine the mechanical behavior of stubby beam-like components. Timoshenko beam theory is well-known to require the shear correction factor in order to recognize the non-uniform shear distribution at a section. While a variety of shear correction factors are appeared in the literature so far, there is still no consensus on the most appropriate form of the shear correction factor. The Saint-Venant's flexure problem is first revisited in the frame work of the classical theory of elasticity and a highly accurate approximate closed-form solution is presented employing the extended Kantorovich method. The resulted approximate solution...
The effect of soil-structure interaction on hysteretic energy demand of buildings
, Article Structural Engineering and Mechanics ; Volume 24, Issue 5 , 2006 , Pages 641-645 ; 12254568 (ISSN) ; Ghannad, M. A ; Sharif University of Technology
Techno-Press
2006
Abstract
The effect of soil-structure interaction (SSI) on hysteresis energy demand of buildings using an ensemble of alluvium site records was investigated. The structure and the soil were molded separately and then combined to constitute the soil-structure model using the sub-structure method. The key parameters effecting the response of the soil-structure system were found to be a non-dimensional frequency as a representative of structure to soil stiffness ratio; and aspect ratio of the building. It was found that the hysteric energy dissipated in a structure under an earthquake can be highly effected when the stiffness of the soil beneath the structure is altered
Interaction curves for in-plane and out-of-plane behaviors of unreinforced masonry walls
, Article Journal of Earthquake Engineering ; Volume 19, Issue 1 , 2015 , Pages 60-84 ; 13632469 (ISSN) ; Aref, A. J ; Whittaker, A. S ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
Different types of macro-elements have been proposed to simulate the behavior of unreinforced masonry (URM) structures under seismic loads. In many of these, macro-elements URM walls are replaced with beam elements with different hysteretic behaviors. The effect of out-of-plane loading or change of gravity load due to the overturning moment is usually not considered in the behavior of these macro-elements. This article presents interaction curves for bidirectional loadings of unreinforced masonry walls to investigate the importance of these factors. Two parameters are systematically changed to derive the interaction curves for a wall with specific dimensions, including compressive traction...
HPGR effect on the particle size and shape of iron ore pellet feed using response surface methodology
, Article Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy ; 2017 , Pages 1-9 ; 03719553 (ISSN) ; Halali, M ; Hejazi, R ; Saghaeian, M ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
In this study the effect of HPGR operational parameters on the dimensional properties of pellet feed was examined and optimized using factorial methodology. The operational parameters considered include feed moisture, specific pressure and roll speed. For this study, size and shape of particles with Blaine number in the range 1800–2200 cm2 g−1 was thoroughly investigated. It was deduced that increasing the specific pressure and decreasing the roll speed would result in reduction of D80 but would increase the Blaine number. The circularity, aspect ratio and roughness descriptors of the particles were measured by SEM micrographs and image analysis software. It was observed that particles...
HPGR effect on the particle size and shape of iron ore pellet feed using response surface methodology
, Article Mineral Processing and Extractive Metallurgy: Transactions of the Institute of Mining and Metallurgy ; Volume 127, Issue 1 , 2018 , Pages 40-48 ; 25726641 (ISSN) ; Halali, M ; Hejazi, R ; Saghaeian, M ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
In this study the effect of HPGR operational parameters on the dimensional properties of pellet feed was examined and optimized using factorial methodology. The operational parameters considered include feed moisture, specific pressure and roll speed. For this study, size and shape of particles with Blaine number in the range 1800–2200 cm2g−1 was thoroughly investigated. It was deduced that increasing the specific pressure and decreasing the roll speed would result in reduction of D80 but would increase the Blaine number. The circularity, aspect ratio and roughness descriptors of the particles were measured by SEM micrographs and image analysis software. It was observed that particles tended...
Small-scale thermoelastic damping in micro-beams utilizing the modified couple stress theory and the dual-phase-lag heat conduction model
, Article Journal of Thermal Stresses ; Volume 42, Issue 7 , 2019 , Pages 801-814 ; 01495739 (ISSN) ; Asghari, M ; Bagheri, E ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
In this article, the size-dependent behavior of micro-beams with the thermoelastic damping (TED) phenomenon is studied. The coupled thermoelasticity equations are derived on the basis of the modified couple stress theory (MCST) and dual-phase-lag (DPL) heat conduction model. By solving these coupled equations simultaneously, a closed-form expression for the TED parameter in micro-beams is presented which considers the small-scale effects incorporation. Then, the effect of various parameters on TED in micro-beams, such as micro-beam height, the type of material, boundary conditions, and aspect ratio is investigated. The results show that the influence of utilizing non-classical continuum and...
Investigation of iron ore particle size and shape on green pellet quality
, Article Canadian Metallurgical Quarterly ; Volume 59, Issue 2 , 2020 , Pages 242-250 ; Halali, M ; Hejazi, R ; Saghaeian, M ; Sheikh Zadeh, V ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Particle size and shape of iron ore concentrate are effective parameters in the production of quality green pellets. In this research, the effect of particle morphology on green pellet quality was studied. It was concluded that pellet quality improved with increasing specific surface area. Drop number and green compression strength of pellets ground by HPGR were found to be superior over those ground in the ball mill. The chief reasons were related to particle shape and the fraction of fine particles. Smaller particle size results in a higher order of bonding between particles and therefore the formation of a stronger system. Also, the rougher and less circular shape of particles resulted in...
Thermal buckling analysis of piezoelectric functionally graded plates with temperature-dependent properties
, Article Mechanics of Advanced Materials and Structures ; Volume 22, Issue 10 , Nov , 2015 , Pages 864-875 ; 15376494 (ISSN) ; Fereidoon, A ; Khaksari Nouri, M ; Mareishi, S ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
In this study, the thermal buckling analysis of hybrid laminated plates made of two-layered functionally graded materials (FGMs) that are integrated with surface-bonded piezoelectric actuators referred to as (P/FGM)s are investigated. Material properties for both substrate FGM layers and piezoelectric layers are temperature-dependent. Uniform temperature rise as a thermal load and constant applied actuator voltage are considered for this analysis. By definition of four new analytic functions, the five coupled governing stability equations, which are derived based on the first-order shear deformation plate theory, are converted into fourth-order and second-order decoupled partial differential...