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Existence and Uniqueness of Solution for Two Free Boundary Problems Modelling Tumor Growth
,
M.Sc. Thesis
Sharif University of Technology
;
Hesaaraki, Mahmoud
(Supervisor)
Abstract
This thesis is based on articles [18,15]. Zhao [18] has studied a free boundary problem modeling the growth of tumors with drug application. In this model live cells are two kindes: proliferative cells and quiescent cells. This model consists of two nonlinear second-order parabolic equations describing the diffusion of nutrient and drug concentration, and three nonlinear first-order hyperbolic equations describing the evolution of proliferative cells, quiescent cells and dead cells. He has proved that this free boundary problem has a unique global solution. Tao and Chen [15] have studied another free boundary problem modelling the growth of an avascular tumour with drug application. The...
A Comparative Study of the Redox Processes of Iodide Ion on Pt, C and Carbon-Polyorthoaminophenol
, M.Sc. Thesis Sharif University of Technology ; Gobal, Feridon (Supervisor)
Abstract
In this study a systematic effort was made to study and compare electrochemical oxidation behavior of iodide on Pt, carbon and carbon supported polyorthoaminophenol film electrodes. All of the electrochemical experiments were performed in acidic, basic and nuteral aqueous solutions and the applied electrochemical techniques included Chronoamperometry (CA) and Cyclic voltammetry (CV). Effects of concentration and scan rate of potential on the cyclic voltammetry of KI was studied at the previously mentioned electrodes. Current-time and log current-potential curves were analyezed quantitavely in order to determine kinetic parameters. Carbon supported polyorthoaminophenol electrode was prepared...
Study on Nucleation and Growth of Titanium Dioxide Nano Particles via Gel-Sol Method
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Nanotechnology is an efficient method suitable for fabrication and production of minimal single dimensional nanometric structures. Such materials and systems can be logically designed that lead to new and optimized biological, chemical and physical properties and characteristics due to their size. Nucleation and growth –appearance of a new phase out of an old phase – is a ubiquitous phenomenon in nature. Fundamental understanding of nanoparticles nucleation and growth mechanism allows more control on form, size and composition and allows tuning of the above said properties easily with use of different reactive conditions as a result of this ability . Nanoparticles of titania are one of...
Assessing the Capacity of the Renewables as the Industrial Driving Force Rather than the Energy Provider, Case Study: Feasibility Study of Wind Turbine Manufacturing in Iran
, M.Sc. Thesis Sharif University of Technology ; Maleki, Abbas (Supervisor)
Abstract
Facing the two challenges of the recession and rising requirement to reduce carbon emissions have led countries around the world to look for ways to promote economic productivity and reduce greenhouse gas emissions. In the meantime, the appearance of renewable energies has the potential to grow and diversify the economy, in addition to providing an effective solution to meet the growing demand for energy. The impact of development of the renewables industry on the economy for each country and each type of renewables can be examined separately. The purpose of this study is to evaluate the development role of wind energy industry as the motive engine of industry and specifically answer two...
Tissue growth into three‐dimensional composite scaffolds with controlled micro‐features and nanotopographical surfaces [electronic resource]
, Article Journal of Biomedical Materials Research Part A ; October 2013, Vol. 101, Issue 10, Pages 2796-2807 ; Simchi, A. (Abdolreza) ; Dunlop, John W. C ; Fratzl, Peter ; Bagheri, R ; Vossoughi, M ; Sharif University of Technology
Abstract
Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 μm) and micro- (∼25 μm) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were...
Application of power law logistic model to growth kinetics of bacillus licheniformis MS3 on a water- insoluble substrate
, Article Chemical Engineering Communications ; Volume 201, Issue 11 , 06 June 2014 , Pages 1514-1525 ; Maghsoudi, E ; Roostaazad, R ; Sharif University of Technology
Abstract
The power law logistic model was utilized to investigate the growth of a hydrocarbon assimilating bacterium on a water-insoluble substrate. To achieve this end, population dynamics of Bacillus licheniformis MS3 in a medium containing n-decane as the sole carbon source was monitored for 30 h. Different initial biosurfactant concentrations and shaking rates were employed to examine the role of mass transfer in the cell growth and the consequent hydrocarbon biodegradation. The amount of n-decane degraded in the system was detected by gas chromatography at the end of the incubation period. The results revealed that when mass transfer limitations were lessened through addition of an initial...
Detecting intermediate particles in the growth of colloidal zinc oxide nanoparticles in different chemical routes using MCR-ALS
, Article Journal of Chemometrics ; Volume 27, Issue 10 , 2013 , Pages 353-358 ; 08869383 (ISSN) ; Jalali Heravi, M ; Kafrashi, F ; Sharif University of Technology
2013
Abstract
Zinc oxide (ZnO) nanoparticles have been used in a wide-ranging of applications such as transparent UV protection, light emitting diodes, sensors and photovoltaic cells. Many applications of ZnO nanoparticles could be improved by changing the particle size, shape and morphology. Therefore, studying the mechanism of shape evolution is crucial for size and shape controlled synthesis of nanocrystaline ZnO particles. As an alternative to sophisticated techniques such as transmission electron microscopy (TEM) and X-ray powder diffraction (XRD), commonly used for studying nanoparticles evolution, we herein employed UV/Vis spectroscopy for monitoring the evolution process of the ZnO nanocrystals...
Vanadium dioxide-anchored porous carbon nanofibers as a Na+ intercalation pseudocapacitance material for development of flexible and super light electrochemical energy storage systems
, Article Applied Materials Today ; Volume 10 , 2018 , Pages 72-85 ; 23529407 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The development of a flexible binder free electrode based on 3D vanadium dioxide (VO2) nano-architectures has materialized as an effective strategy for fabrication of advanced wearable, portable, and stretchable electronic devices. However, most of the stretchable energy storage devices based on VO2 suffer from a relatively low operating voltage, high weight, low specific capacitance, and thus low energy density. Here, a novel binder free supercapacitor electrode composed of hierarchical VO2 nanosheet arrays grown on porous carbon nanofibers (VO2@PCNFs) is designed using a simple hydrothermal method followed by annealing treatment. The electrochemical evaluation confirmed that the energy...
A kinetic study of facile fabrication of MIL-101(Cr) metal-organic framework: effect of synthetic method
, Article Inorganica Chimica Acta ; Volume 471 , 2018 , Pages 513-520 ; 00201693 (ISSN) ; Kazemeini, M ; Sharif University of Technology
Elsevier S.A
2018
Abstract
MIL-101(Cr) metal–organic framework samples were successfully synthesized through the conventional electrical heating (CE), ultrasound (US), and microwave (MW) synthetic methods at three different temperatures and various synthesis times. These were done with the aim of understudying the crystallization kinetics of these complex MIL's structures. The nucleation and crystal growth steps were thus, quantified through measuring the relative crystallinity of the prepared MIL-101(Cr) utilizing the PXRD and FESEM analysis under various synthesis conditions. In addition, the textural properties of the fully crystallized samples measured through the N2 adsorption–desorption isotherms at 77 K. The...
Master sintering curves of a nanoscale 3Y-TZP powder compacts
, Article Ceramics International ; Volume 35, Issue 2 , 2009 , Pages 547-554 ; 02728842 (ISSN) ; Simchi, A ; Dourandish, M ; Golestani Fard, F ; Sharif University of Technology
2009
Abstract
The sintering behavior of commercially available granulated ZrO2-3 mol% Y2O3 (3Y-TZP) powder compacts with an aggregate size of 75 nm was studied. The shrinkage response of the powder compacts during non-isothermal sintering was measured in a sensitive dilatometer at different heating rates. Densification and grain growth were also studied after isothermal firing in air according to different sintering cycles. The sintering and grain growth activation energy was estimated to be QS = 485 ± 12 kJ mol-1 and QG = 546 ± 23 kJ mol-1, respectively. Using the estimated Q-values, the master curves for sintering and grain growth were established and used for prediction of the densification and...
A study on electrochemical growth behavior of the Co-Ni alloy nanowires in anodic aluminum oxide template
, Article Journal of Alloys and Compounds ; Volume 480, Issue 2 , 2009 , Pages 275-278 ; 09258388 (ISSN) ; Dolati, A ; Sharif University of Technology
2009
Abstract
This study shows the growth behavior of Co-Ni alloy nanowires in AAO template. Growth of nanowires consists of four different stages namely electronucleation, steady state growth, filling of pores, and coverage of filled nanowires and forming of a film on the template surface. TEM study of nanowires showed that the nanowires possess hemispherical head due to the preferable and more rapid growth phenomenon in central section of nanowires instead of edge sides. Studies on the relations between nanowires composition and ion concentration in solution showed that growth of nanowires is a diffusion-controlled process. The compositional, structural and magnetic properties of nanowires were...
Three-dimensional modeling of avascular tumor growth in both static and dynamic culture platforms
, Article Micromachines ; Volume 10, Issue 9 , 2019 ; 2072666X (ISSN) ; Barisam, M ; Saidi, M. S ; Kashaninejad, N ; Nguyen, N. T ; Sharif University of Technology
MDPI AG
2019
Abstract
Microfluidic cell culture platforms are ideal candidates for modeling the native tumor microenvironment because they can precisely reconstruct in vivo cellular behavior. Moreover, mathematical modeling of tumor growth can pave the way toward description and prediction of growth pattern as well as improving cancer treatment. In this study, a modified mathematical model based on concentration distribution is applied to tumor growth in both conventional static culture and dynamic microfluidic cell culture systems. Apoptosis and necrosis mechanisms are considered as the main inhibitory factors in the model, while tumor growth rate and nutrient consumption rate are modified in both quiescent and...
Diffusive logistic equations with harvesting and heterogeneity under strong growth rate
, Article Advances in Nonlinear Analysis ; Volume 8, Issue 1 , 2019 , Pages 455-467 ; 21919496 (ISSN) ; Torabi Tehrani, H ; Sharif University of Technology
De Gruyter
2019
Abstract
We consider the equation (equation presented) where Ω is a smooth bounded domain in ℝ N , b(x) and h(x) are nonnegative functions, and there exists Ω 0 ⊃ Ω such that {x : b(x) = 0} = Ω0. We investigate the existence of positive solutions of this equation for c large under the strong growth rate assumption a ≥ λ 1 (Ω0), where λ 1 (Ω0) is the first eigenvalue of the δ in Ω0 with Dirichlet boundary condition. We show that if h = 0 in Ω\u03a90, then our equation has a unique positive solution for all c large, provided that a is in a right neighborhood of λ 1 (Ω0). For this purpose, we prove and utilize some new results on the positive solution set of this equation in the weak growth rate case
Dataset of the application of handheld NIR and machine learning for chicken fillet authenticity study
, Article Data in Brief ; Volume 29 , 2020 ; Weesepoel, Y ; Parastar, H ; van den Doel, A ; Buydens, L ; Jansen, J ; Sharif University of Technology
Elsevier Inc
2020
Abstract
Diffuse reflectance near-infrared (NIR) data (908–1676 nm) of chicken breast fillets was recorded in a non-destructive way using a portable miniaturised NIR spectrometer. The NIR data was used to discriminate between fresh and thawed breast fillets and to determine the birds’ growth conditions. NIR data was recorded of 153 commercial supermarket chicken fillet samples by applying the NIR device equipped with the standard issue collar on the samples in three different ways: (i) directly on the meat (ii) through the top foil of the package (i.e. with an air pocket between the foil and the breast fillet), and (iii) through the top foil with the packaging turned bottom up (i.e. no air pocket...
Conformal curves on the WO3 surface
, Article Physical Review Letters ; Volume 100, Issue 4 , 2008 ; 00319007 (ISSN) ; Rajabpour, M. A ; Rouhani, S ; Sharif University of Technology
2008
Abstract
We have studied the isoheight lines on the WO3 surface as a physical candidate for conformally invariant curves. We have shown that these lines are conformally invariant with the same statistics of domain walls in the critical Ising model. They belong to the family of conformal invariant curves called Schramm-Loewner evolution (or SLEκ), with diffusivity of κ∼3. This can be regarded as the first experimental observation of SLE curves. We have also argued that Ballistic Deposition (BD) can serve as a growth model giving rise to contours with similar statistics at large scales. © 2008 The American Physical Society
Structure formation in a variable dark energy model and observational constraints
, Article ESO Astrophysics Symposia ; Volume 2008 , 2008 , Pages 3-7 ; 14312433 (ISSN); 3540747125 (ISBN); 9783540747123 (ISBN) ; Movahed, M. S ; Sharif University of Technology
2008
Abstract
The interpretation of a vast number of cosmological observations in the framework of FRW models suggests that the major part of the energy density of the universe is in form of dark energy with still unknown physical nature. In some models for dark energy, which are motivated by particle physics theory, the equation of state and the contribution of dark energy to the energy density of the universe can be variable. Here we study structure formation in a parameterized dark energy model, and compare its predictions with recent observational data, from the Supernova Ia gold sample and the parameters of large scale structure determined by the 2-degree Field Galaxy Redshift Survey (2dFGRS), and...
High resolution simulations of unstable modes in a collisionless disc
, Article Astronomy and Astrophysics ; Volume 473, Issue 1 , 2007 , Pages 31-40 ; 00046361 (ISSN) ; Just, A ; Korchagin, V. I ; Jalali, M. A ; Sharif University of Technology
2007
Abstract
We present N-body simulations of unstable spiral modes in a dynamically cool collisionless disc. We show that spiral modes grow in a thin collisionless disk in accordance with the analytical perturbation theory. We use the particle-mesh code SUPERBOX with nested grids to follow the evolution of unstable spirals that emerge from an unstable equilibrium state. We use a large number of particles (up to N = 40 & 106) and high-resolution spatial grids in our simulations (1283 cells). These allow us to trace the dynamics of the unstable spiral modes until their wave amplitudes are saturated due to nonlinear effects. In general, the results of our simulations are in agreement with the analytical...
Addressing the growth failure of the oil economies: The role of financial development
, Article Quarterly Review of Economics and Finance ; Volume 46, Issue 5 , 2007 , Pages 726-740 ; 10629769 (ISSN) ; Rastad, M ; Sharif University of Technology
2007
Abstract
The oil exporting countries have experienced a relatively continuous fall in GDP per capita over the last 30 years. This is in spite of benefiting from a more than average of the rest of the world investment rate. The findings of this paper, report a lower level of financial development for the oil economies when compared with the rest of the world. We will show in this paper that the higher rate of investment of the oil economies can be explained mainly by the oil revenues and surprisingly, financial development has a net dampening effect on investment for these economies. The paper also shows that the weakness of financial institutions, contributes to the poor performance of economic...
An analytical and experimental investigation on the normal grain growth in metals using the Monte Carlo method
, Article Materials and Design ; Volume 28, Issue 9 , 2007 , Pages 2533-2539 ; 02613069 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
Elsevier Ltd
2007
Abstract
The prediction of material microstructure is of great interest to the material designers since the property and performance of materials depend strongly on their microstructures. In this work, a Monte Carlo approach is used to investigate the normal grain growth of aluminum and pure copper. The grain growth was calculated at certain temperatures using the grain growth law and compared with the simulation results by varying the Q as a parameter of simulation lattice orientation for pure aluminum. Also the results predicted by the Monte Carlo method showed a good agreement with the experimental results of grain growth of pure cooper. It was found that increase in Q increases the accuracy of...
Sulfide removal by natural mix of chemotrophic sulfide oxidizing bacteria in anaerobic conditions
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Vossoughi, M ; Soltanieh, M ; Rizi, Z. T ; Sharif University of Technology
2006
Abstract
Most sulfide oxidizing bioreactors are based on pure cultures or artificial mixes of microorganisms with strict requirements for growth, which make the system unstable and do not guarantee their long term performance. The ultimate goal of this study is to develop a natural mix of chemotrophic bacteria that may be applied anaerobically for the treatment of sour gas. Activated sludge from local municipal wastewater treatment plant that was maintained in endogenous anaerobic conditions for one year was used in this study. Total suspended solids (TSS) and volatile suspended solids (VSS) of the sludge was 22 gl-1 and 14.3 gl-1, respectively. A glass culture vessel had a volume of 0.65 L was used...