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sayyad--sharareh
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Emerging bioengineering strategies for regulating stem cell fate: Scaffold physical and biochemical cues
, Article Tissue Engineering: Current Status and Challenges ; 2022 , Pages 125-156 ; 9780128240649 (ISBN) ; Mashayekhan, S ; Sharif University of Technology
Elsevier
2022
Abstract
Stem cell therapy has been introduced as an emerging approach for injured tissue regeneration. This chapter addresses developing regenerative medicine techniques for controlling stem cell behavior. Recent studies have been reviewed and novel approaches have been divided into four main categories: 3D bioprinting, lithography, microfluidics, and electrospinning. Moreover, the impact of applied biophysical and/or biochemical cues to the designed scaffold on controlling stem cell activity has been discussed. The potential of using stem cells for various soft and hard tissue regenerations has been explored in different bioengineered scaffolds and the applied techniques for controlling stem cell...
Neutral Spin Collective Mode in Carbon Nanotubes
, M.Sc. Thesis Sharif University of Technology ; Jafari, Akbar (Supervisor)
Abstract
In 2002 Baskaran and Jafari published an article that was about a spin-1 collective mode. Similarity between carbon nanotubes and graphene was a motivation for working on this project, in order to find another spin mode by considering random phase approximation as a simple way of finding collective motion of a physical systems. Moreover rolling graphene sheet induce diffrent physical properties as a result of chiral axis . In this project we focus only on achiral nanotubes and at last find two collective modes in this structures
A Study on the Shannon Zero Error Capacity of Graphs
, M.Sc. Thesis Sharif University of Technology ; Jafari, Amir (Supervisor) ; Alipour, Sharareh (Supervisor)
Abstract
The issue of reliability, which is associated with a low probability of error in a communication system, is an important parameter in information theory. By reliability, we mean a low decoding error probability, and one of the main criteria for this is the zero decoding error probability. In the zero-error probability, the decoding error probability for any code is exactly zero. Error-free capacity was examined by Claude Shannon in 1956. The Shannon capacity of a communication channel is defined using the independent sets of strong products of graph. Shannon calculated the capacity of graphs up to five vertices except the graphC5. Lovász, in 1979, using the upper bound he provided, was able...
Nematicity-enhanced superconductivity in systems with a non-Fermi liquid behavior
, Article Journal of Physics Condensed Matter ; Volume 35, Issue 24 , 2023 ; 09538984 (ISSN) ; Kitatani, M ; Vaezi, A ; Aoki, H ; Sharif University of Technology
Institute of Physics
2023
Abstract
We explore the interplay between nematicity (spontaneous breaking of the sixfold rotational symmetry), superconductivity, and non-Fermi liquid behavior in partially flat-band (PFB) models on the triangular lattice. A key result is that the nematicity (Pomeranchuk instability), which is driven by many-body effect and stronger in flat-band systems, enhances superconducting transition temperature in a systematic manner on the T c dome. There, a plausible s x 2 + y 2 − d x 2 − y 2 − d x y -wave symmetry, in place of the conventional d x 2 − y 2 -wave, governs the nematicity-enhanced pairing with a sharp rise in the T c dome on the filling axis. When the sixfold symmetry is spontaneously broken,...
A non parametric approach to monitor simple linear profiles in phases I and II
, Article Communications in Statistics - Theory and Methods ; Volume 46, Issue 11 , 2017 , Pages 5203-5222 ; 03610926 (ISSN) ; Akhavan Niaki, S. T ; Afshar Najafi, B ; Sharif University of Technology
Taylor and Francis Inc
2017
Abstract
In this paper, a non parametric approach is first proposed to monitor simple linear profiles with non normal error terms in Phase I and Phase II. In this approach, two control charts based on a transformation technique and decision on beliefs are designed in order to monitor the intercept and the slope, simultaneously. Then, some simulation experiments are performed in order to evaluate the performance of the proposed control charts in Phase II under both step and drift shifts in terms of out-of-control average run length (ARL1). Besides, the performance of the proposed control charts is compared to the ones of seven other existing schemes in the literature. Simulation results show that the...
A numerical simulation to effectively assess impacts of flow channels characteristics on solid oxide fuel cell performance
, Article Energy Conversion and Management ; Volume 244 , 2021 ; 01968904 (ISSN) ; Adavi, K ; Sayyad Amin, J ; Zendehboudi, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Solid oxide fuel cells (SOFCs) introduce a promising electrochemical conversion technology to generate electricity directly from fuel oxidization. A three-dimensional (3D) numerical model is proposed to evaluate the SOFC performance by employing computational fluid dynamics (CFD) approach based on the finite element method. This research includes simultaneously solving momentum, energy, and mass transport equations linked with the electrochemical reactions. First, the modeling results of a SOFC system with a rectangular channel in the absence of obstacles are compared with the experimental data, showing very good agreement. The effects of different shapes and numbers of obstacles on fuel...
A Method for Conceptual Design and Component Sizing of a Hybrid Electric Vehicle Powertrain
, M.Sc. Thesis Sharif University of Technology ; Saadat Foumani, Mahmoud (Supervisor) ; Nasiri, Sayyad (Co-Advisor)
Abstract
One of the main and challenging stages in the development of hybrid vehicles (HEVs) is the conceptual design of its powertrain, which includes two parts: architecture design and sizing. This research aims to introduce a novel framework for conceptual design of HEV powertrains. By using this framework, not only the sizing of components is optimized but also the optimal architecture of powertrain is selected. In the proposed framework, by finding the optimal values of the powertrain design variables, including type of architecture and sizing variables (such as nominal powers, nominal torques, conversion ratios, etc.), the performance and the cost of hybrid vehicle is optimized in three layers...
Multivariate curve resolution alternating least-squares as a tool for analyzing crude oil extracted asphaltene samples
, Article Energy and Fuels ; Volume 26, Issue 9 , 2012 , Pages 5663-5671 ; 08870624 (ISSN) ; Hemmateenejad, B ; Sedghamiz, T ; Khosousi, T ; Ayatollahi, S ; Seiedi, O ; Sayyad Amin, J ; Sharif University of Technology
ACS
2012
Abstract
Asphaltene deposition in the early stage of the oil reservoir life and later during any stimulation process emerges critical problems to the petroleum industry. Deposition of asphaltene aggregates raises strict problems in industries and demands markedly a practical and scientific knowledge of the mechanisms of aggregation and precipitation. Fluorescence emission spectroscopy has been widely used to illuminate the fundamental properties of crude oils and asphaltenes. It proposes analysis of some details of equilibrium, dynamic behavior, and aggregation composition of crude oil under specific condition. In this work, the fluorescence spectra of crude-oil extracted asphaltene samples were...
Pairing and non-Fermi liquid behavior in partially flat-band systems: Beyond nesting physics
, Article Physical Review B ; Volume 101, Issue 1 , 2020 ; Huang, E. W ; Kitatani, M ; Vaezi, M. S ; Nussinov, Z ; Vaezi, A ; Aoki, H ; Sharif University of Technology
American Physical Society
2020
Abstract
While many-body effects in flat-band systems are receiving renewed hot interest in condensed-matter physics for superconducting and topological properties as well as for magnetism, studies have primarily been restricted to multiband systems (with coexisting flat and dispersive bands). Here we focus on one-band systems where a band is "partially flat," comprising flat and dispersive portions in k space to reveal whether intriguing correlation effects can already arise on the simplest possible one-band level. For that, the two-dimensional repulsive Hubbard model is studied for two models having different flat areas in an intermediate-coupling regime with the dynamical mean-field theory...