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#### An example of non-embeddability of the Ricci flow

, Article Annals of Global Analysis and Geometry ; Volume 55, Issue 4 , 2019 , Pages 681-685 ; 0232704X (ISSN) ; Sharif University of Technology
Springer Netherlands
2019

Abstract

For an evolution of metrics (M, g t ) there is a t-smooth family of embeddings e t : M→ R N inducing g t , but in general there is no family of embeddings extending a given initial embedding e. We give an example of this phenomenon when g t is the evolution of g under the Ricci flow. We show that there are embeddings e inducing g which do not admit of t-smooth extensions to e t inducing g t for any t> 0. We also find hypersurfaces of dim > 2 that will not remain a hypersurface under Ricci flow for any positive time. © 2019, Springer Nature B.V

#### Global optimal regularity for variational problems with nonsmooth non-strictly convex gradient constraints

, Article Journal of Differential Equations ; Volume 279 , 2021 , Pages 76-135 ; 00220396 (ISSN) ; Sharif University of Technology
Academic Press Inc
2021

Abstract

We prove the optimal W2,∞ regularity for variational problems with convex gradient constraints. We do not assume any regularity of the constraints; so the constraints can be nonsmooth, and they need not be strictly convex. When the domain is smooth enough, we show that the optimal regularity holds up to the boundary. In this process, we also characterize the set of singular points of the viscosity solutions to some Hamilton-Jacobi equations. Furthermore, we obtain an explicit formula for the second derivative of these viscosity solutions; and we show that the second derivatives satisfy a monotonicity property. © 2021 Elsevier Inc

#### Double obstacle problems and fully nonlinear PDE with non-strictly convex gradient constraints

, Article Journal of Differential Equations ; Volume 278 , 2021 , Pages 358-392 ; 00220396 (ISSN) ; Sharif University of Technology
Academic Press Inc
2021

Abstract

We prove the optimal W2,∞ regularity for fully nonlinear elliptic equations with convex gradient constraints. We do not assume any regularity about the constraints; so the constraints need not be C1 or strictly convex. We also show that the optimal regularity holds up to the boundary. Our approach is to show that these elliptic equations with gradient constraints are related to some fully nonlinear double obstacle problems. Then we prove the optimal W2,∞ regularity for the double obstacle problems. In this process, we also employ the monotonicity property for the second derivative of obstacles, which we have obtained in a previous work. © 2021 Elsevier Inc

#### Mechanism of transition metal interaction with graphene sheet reflected in its plasmonic excitations: Effect of gas adsorption phenomena studied by a combination of solid state and molecular orbital approaches

, Article Applied Surface Science ; Volume 554 , July , 2021 ; 01694332 (ISSN) ; Shamkhali, A. N ; Safdari, F ; Abedi, M ; Ellialtıoğlu, Ş ; Sharif University of Technology
Elsevier B. V
2021

Abstract

In this study, plasmonic properties of transition metal atoms (Sc-Zn, Pd, Pt) adsorbed on various sites of graphene sheets were investigated before and after CO adsorption by density functional theory (DFT). To this aim, Electron Energy Loss Spectroscopy (EELS) of these systems were obtained by periodic DFT. The results indicated that the highest in-plane plasmon peaks undergo blue shifts after CO adsorption, in such a way that Co–graphene system demonstrates the highest blue shift of 2.42 eV from Visible to UV region. Also, out-of-plane plasmons do not exhibit significant sensitivity to CO adsorption. For deeper understanding of electronic structure of metal-graphene systems, appropriate...

#### Genuine empathy with inanimate objects

, Article Phenomenology and the Cognitive Sciences ; Volume 20, Issue 5 , 2021 , Pages 831-846 ; 15687759 (ISSN) ; Sharif University of Technology
Springer Science and Business Media B.V
2021

Abstract

How do we enter into empathic relations with inanimate objects (IO)? Do we indirectly infer that they possess mental states, or directly perceive them as mental things? In recent years these questions have been addressed by a number of authors. Some argue in favor of an indirect approach that involves mediatory procedures; others defend a direct approach that postulates no intermediate. In this paper I argue on the side of the latter. I show that Simulation Theory (ST), one of the most elaborated versions of the indirect approach, does not have the capacity to account for our empathy with IO. Investigating ST paves the way for criticizing a special kind of indirect theory, namely Imaginative...

#### The Ricci Flow with Applications to the Poincare and Calabi Conjectures

, M.Sc. Thesis Sharif University of Technology ; Bahreini, Alireza (Supervisor)
Abstract

Poincare conjecture is one of the rst eorts for classifying 3-manifolds that was stated in the begining of 20th century. Eorts for proving this conjecture continued for about 100 years and nally Perelman has solved it in 2003. He has used Ricci ow which has been invented by Richard Hamilton in the early 80's. In this thesis rst we will introduce Ricci ow and will state the results before Perelman such as short time and long time existence of solution. Then we will mention some applications of Ricci ow and will state an explanation of the proof of uniformization and Calabi conjecture by Ricci ow. After that we start the main part of the thesis. In this part we will montion one of the...

#### Weak Solutions of the Euler Equations and Onsager’s Conjecture

, M.Sc. Thesis Sharif University of Technology ; Safdari, Mohammad (Supervisor)
Abstract

The Onsager's conjecture is concerned with the dichotomy between rigidity and flexibility of weak solutions of incompressible Euler equations. Lars Onsager conjectured that weak solutions of Euler equations that are not smooth enough could be dissipative, even without the help of viscosity. On the other hand, it is well known that $C^1$ solutions conserve energy. Onsager conjectured that C^(1/3) regularity marks the threshold for this dichotomy. In other words, Hölder continuous solutions with Hölder exponent greater than 1/3 conserve the energy, while for every Hölder exponent less than 1/3, there are dissipative Hölder continuous solutions. The threshold 1/3 is intimately tied with...

#### Influence of quantum effect on deviation from linear isotherm regularity

, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 555-560 ; 10263098 (ISSN) ; Parsafar, G. A ; Sharif University of Technology
2012

Abstract

A general regularity was found based on an effective pair potential of Lennard-Jones LJ (12, 6), for both dense, nonmetallic and nonionic fluids and solids according to which (Z-1) v2 linearly varies with respect to ρ2 for each isotherm, and this equation of state (EoS I) is known as LIR. However, despite the fact that Ne is a simple spherical species, unexpectedly, its solid and liquid phases both show a significant deviation from EoS I. In this work, we have investigated the accuracy of the EoS I for other systems, including quantum light molecules, such as D 2, H 2 and He, in both fluid and solid states at different temperatures. Like Ne, we have noticed that these systems do not well...

#### A Review of Some Results of Kac’s Program in Kinetic Theory

, M.Sc. Thesis Sharif University of Technology ; Safdari, Mohammad (Supervisor)
Abstract

This thesis is devoted to the study of suitable functional frameworks for proving propagation of chaos and mean-field limit of nonlinear Vlasov-type equations for indistinguishable particles. The Kac model is a classic example and the motivation of this functional structure. On the one hand, Kac considered a spatially homogeneous gas, and on the other hand, he reduced the problem to one-dimensional collisions and dropped the conservation of momentum assumption. Therefore, he obtained a simplified version of the Boltzmann equation, which is named after him, the Kac equation. The main results which we study are quantitative estimates

on the decay of fluctuations around the deterministic...

on the decay of fluctuations around the deterministic...

#### Determinants of the Quality of Corporate Social Responsibility Disclosures in Iran’s Stock Market

, M.Sc. Thesis Sharif University of Technology ; Ebrahimnejad, Ali (Supervisor)
Abstract

This study examines the quality of Corporate Social Responsibility (CSR) disclosure among publicly listed companies in Iran and identifies the factors that influene it. The research sample consists of 546 companies listed on the Tehran Stock Exchange and Iran Fara Bourse, covering the period from February 2023 to January 2024. Data were extracted from audited financial statements and the annual reports of the companies' boards of directors. In the first part of the study, a CSR disclosure quality index comprising 39 factors was developed. The annual reports of the companies were then analyzed to calculate a disclosure score for each company. The average CSR disclosure quality score was...

#### Equation of State for Dense Systems of Light Molecules in Fluid and Solid States

, M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholam Abbas (Supervisor)
Abstract

A general regularity has been found based on an effective pair potential of Lennard-Jones LJ (12, 6) for both dense nonmetallic and nonionic fluids and solids; namely, (Z-1)V2 linearly varies with respect to ρ2, this equation of state (EoS I) is known as LIR. The other equation of state (EoS II), according to wich the isotherm of (Z-1)V2 is linear in term of 1/ρ, wich gives a good description for the metallic and ionic fluids and solids. This equation of state was suggested based on an effective pair potential of LJ (6, 3). Unexpectedly, solid and liquid Ne indicates a significant deviations from EoS I. Recently, a general equation of state (EoS III) based on an effective near-neighbor pair...

#### Investigating Ethical Consequences of the Information and Communication Technologies (ICT) with Respect to Luciano Floridi’s Philosophy and Ethics of Information

, M.Sc. Thesis Sharif University of Technology ; Taghvai, Mostafa (Supervisor)
Abstract

The main purpose of this dissertation is to give an ethical evaluation of one of the consequences of ICT. Since these technologies are present in every corner of our personal and social life, recognizing their ethical and social consequences are of vital importance. The present dissertation, which is set up in 3 chapters, is allocated for evaluating one of these consequences. In the first chapter which is the first step of our overall argument indeed, one of recent theories in Cognitive Psychology and memory studies, namely Working Memory will be introduced. In the second chapter, introducing another theory in Cognitive Psychology namely Cognitive Load Theory, the role of Working Memory in...

#### The Nature of Folk Psychology and Its Implications for Designing Artificial Agents and Humanoid Robots

, Ph.D. Dissertation Sharif University of Technology ; Azadegan, Ebrahim (Supervisor)
Abstract

How do we enter into empathic relations with inanimate objects (IO)? Do we indirectly infer that they possess mental states, or directly perceive them as mental things? In recent years these questions have been addressed by a number of authors. Some argue in favor of an indirect approach that involves mediatory procedures; others defend a direct approach that postulates no intermediate. In this paper I argue on the side of the latter. I show that Simulation Theory (ST), one of the most elaborated versions of the indirect approach, does not have the capacity to account for our empathy with IO.Investigating ST paves the way for criticizing a special kind of indirect theory, namely Imaginative...

#### Stability of the Schwarzschild Family of Solutions in General Relativity

, M.Sc. Thesis Sharif University of Technology ; Safdari, Mohammad (Supervisor)
Abstract

In 1952, Choquet-Bruhat proved the well-posedness of the Cauchy problem for Einstein’s equation, and demonstrated that a given initial data on a Cauchy hypersurface in spacetime propagates forward in time as a solution to the wave equation. It took nearly half a century for mathematicians to build the necessary tools and techniques for proving the stability of the most basic solution of Einstein’s vacuum equations (EVE), namely Minkowski spacetime. In 1993, Christodoulou and Klainerman showed the global nonlinear stability of this solution using the concept of a double null gauge. The Schwarzschild solution, introduced by Karl Schwarzschild in 1916 for spherically symmetric spacetimes as an...

#### Optimization of operating parameters and rate of uranium bioleaching from a low-grade ore

, Article Journal of Radioanalytical and Nuclear Chemistry ; Vol. 301, issue. 2 , 2014 , pp. 341-350 ; ISSN: 02365731 ; Roosta-Azad, R ; Safdari, S. J ; Sharif University of Technology
2014

Abstract

In this study the bioleaching of a low-grade uranium ore containing 480 ppm uranium has been reported. The studies involved extraction of uranium using Acidithiobacillus ferrooxidans derived from the uranium mine samples. The maximum specific growth rate (μ max) and doubling time (t d) were obtained 0.08 h-1 and 8.66 h, respectively. Parameters such as Fe2+ concentration, particle size, temperature and pH were optimized. The effect of pulp density (PD) was also studied. Maximum uranium bio-dissolution of 100 ± 5 % was achieved under the conditions of pH 2.0, 5 % PD and 35 °C in 48 h with the particles of d 80 = 100 μm. The optimum concentration of supplementary Fe2+ was dependent to the PD....

#### Sandpile Model on Height Parameters

, M.Sc. Thesis Sharif University of Technology ; Moghimi Araghi, Saman (Supervisor)
Abstract

Many statistical systems such as earthquakes, road trafcs, forest fres, neurocortical avalanches etc. exhibit self-organized criticality (SOC). In such systems without tuning extrenal parameters, the system arrives at criticality. During recent decades, a number of models are introduced which show the same charactristics. These models have made a platform to investigate the physics of self-organized criticality. Among them, sandpile models are the best known models. They exhibit critical behaviour such as scaling laws. Also in some of them conformal invariance is checked nummerically.Most of sandpile models deal with slope parameters, that is, the main dynamical parameters are the local...

#### What happened to complex product systems literature over the last two decades: progresses so far and path ahead

, Article Technology Analysis and Strategic Management ; Volume 30, Issue 8 , 2018 , Pages 948-966 ; 09537325 (ISSN) ; Park, T. Y ; Kiamehr, M ; Sharif University of Technology
Routledge
2018

Abstract

Complex product systems (CoPS) industries largely contribute to industrial development, economic growth and creation of national wealth in both developed and developing economies. CoPS also show a number of specific characteristics as a distinctive category of industrial products in comparison with mass-produced consumer goods. These aspects have attracted the attention of scholars to study CoPS over the last two decades, resulting in a fairly extensive body of literature on the subject. However, there is a further need to connect research findings in this area, to illustrate a macro view of the development in the field, explore common themes, and identify possible paths into the future....

#### Hibert Scheme and Gromov-Witten Invariant

, M.Sc. Thesis Sharif University of Technology ; Safdari, Mohammad (Supervisor) ; Setayesh, Iman (Co-Supervisor)
Abstract

The aim of these notes is to describe an exciting chapter in the recent development of quantum cohomology. Guided by ideas from physics, a remarkable structure on the solutions of certain rational enumerative geometry problems has been found: the solutions are coeﬃcients in the multiplication table of a quantum cohomology ring. Associativity of the ring yields non-trivial relations among the enumerative solutions. In many cases, these relations suﬃce to solve the enumerative problem. For example, let $N_d$ be the number of degree $d$, rational plane curves passing through $3d$ − $1$ general points in $\mathbb{P}^2$. Since there is a unique line passing through 2 points, $N_1 = 1$. The...

#### Prediction of flooding in a pulsed packed column for continuous pertraction of dysprosium by an emulsion liquid membrane

, Article Chemical Engineering and Processing - Process Intensification ; Volume 169 , 2021 ; 02552701 (ISSN) ; Bastani, D ; Safdari, J ; Raji, M ; Sharif University of Technology
Elsevier B.V
2021

Abstract

For the first time, Dysprosium was extracted by the novel method of emulsion liquid membrane in a pulsed packed column in a continuous process. Emulsion liquid membrane (ELM) was comprised of D2EHPA (di-2-ethylhexylphosphoric acid) as carrier and Span 80 (Polysorbate 80) as the surfactant in kerosene as the diluent and nitric acid as internal phase. In this work, the packed column was characterized from a hydrodynamic point of view including flooding condition and holdup at flooding points. Operational parameters affecting the flooding points, such as pulsation intensity and flow rate of continuous and dispersed phases have been studied. It was found that increase in pulsation intensity up...

#### Modeling Multiphase Fluid Flow Using SPH

, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor)
Abstract

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian method for simulation of fluid flow. Movable particles are used to interpolate fluid properties instead of fixed Eulerian grids in this method. By essence, the aforesaid particles are movable points which carry the fluid properties such as temperature, enthalpy, density, etc. these variables can also be the stress, strain or the rheological properties of the fluid. Thus, this method needs no grids and the fluid properties are calculated using an interpolation mechanism which classifies this method as meshless. A computational code is designed using SPH for the simulation of multiphase flows. Usage of the Lagrangian formulation has made it...