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riazi--ardalan
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Generalized noncommutative gauge theory
, Article Proceedings of the 13th Regional Conference on Mathematical Physics, Antalya ; 2013 , Pages 185-192 ; 9789814417525 (ISBN) ; Sharif University of Technology
2013
Abstract
The structure of the translationally invariant noncommutative field theory in determined and the corresponding gauge theory is presented
Cutoff function in holographic RG flow
, Article Physical Review D ; Volume 99, Issue 10 , 2019 ; 24700010 (ISSN) ; Sharif University of Technology
American Physical Society
2019
Abstract
Using the precursor map in AdS/CFT, the renormalization group cutoff function is mapped to the dual theory. The resulting flow equations on the two sides of the duality are compared. © 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3
Brane cosmology with string antisymmetric field
, Article 12th Regional Conference on Mathematical Physics, Islamabad, 27 March 2006 through 1 April 2006 ; 2007 , Pages 73-78 ; 9812705910 (ISBN); 9789812705914 (ISBN) ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2007
Abstract
The equations of a string inspired noncommutative gravity model on a brane are shown to admit a first integral, generalizing the five dimensional Friedman equation for the FRW Hubble parameter. Copyright © 2007 by World Scientific Publishing Co. Pvt. Ltd
Translational-invariant noncommutative gauge theory
, Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Volume 83, Issue 2 , 2011 ; 15507998 (ISSN) ; Sadooghi, N ; Sharif University of Technology
2011
Abstract
A generalized translational-invariant noncommutative field theory is analyzed in detail, and a complete description of translational-invariant noncommutative structures is worked out. The relevant gauge theory is described, and the planar and nonplanar axial anomalies are obtained
Anomaly and nonplanar diagrams in noncommutative gauge theories
, Article International Journal of Modern Physics A ; Volume 17, Issue 1 , 2002 , Pages 123-144 ; 0217751X (ISSN) ; Sadooghi, N ; Sharif University of Technology
2002
Abstract
Anomalies arising from nonplanar triangle diagrams of noncommutative gauge theory are studied. Local chiral gauge anomalies for both noncommutative U(1) and U(N) gauge theories with adjoint matter fields are shown to vanish. For noncommutative QED with fundamental matters, due to UV/IR mixing a finite anomaly emerges from the nonplanar contributions. It involves a generalized *-product of gauge fields
Planar and nonplanar konishi anomalies and effective superpotential for noncommutative N = 1 supersymmetric U(1)
, Article International Journal of Modern Physics A ; Volume 20, Issue 13 , 2005 , Pages 2859-2892 ; 0217751X (ISSN) ; Sadooghl, N ; Sharif University of Technology
2005
Abstract
The Konishi anomalies for noncommutative N = 1 supersymmetric U(1) gauge theory arising from planar and nonplanar diagrams are calculated. Whereas planar Konishi anomaly is the expected *-deformation of the commutative anomaly, nonplanar anomaly reflects the important features of nonplanar diagrams of noncommutative gauge theories, such as UV/IR mixing and the appearance of nonlocal open Wilson lines. We use the planar and nonplanar Konishi anomalies to calculate the effective superpotential of the theory. In the limit of vanishing |⊖p, with ⊖ the noncommutativity parameter, the noncommutative effective superpotential depends on a gauge invariant superfield, which includes supersymmetric...
Axial anomaly in noncommutative QED on R4
, Article International Journal of Modern Physics A ; Volume 16, Issue 18 , 2001 , Pages 3151-3177 ; 0217751X (ISSN) ; Sadooghi, N ; Sharif University of Technology
2001
Abstract
The axial anomaly of the noncommutative U(1) gauge theory is calculated by a number of methods and compared with the commutative one. It is found to be given by the corresponding Chern class
String Theory Discription on Non-Relativistic QFT
,
Ph.D. Dissertation
Sharif University of Technology
;
Ardalan, Farhad
(Supervisor)
Abstract
In this Thesis we study the string theory discription of non-relativistic quantum ?eld theories.In other statement we study the duality between gravity and gauge theory with non-relativistic symmetry.We discuss that this duality works in non rel- ativistic sense.We study two kind of non-relativistic theories that one of them camefrom string theory and other model obtained by special transformation of original relativistic theory and we see that how duality can be work for these models.Also dual picture of semi-classical string in the background that found from string theorystudied.We also study the motion of particle in a hot plasma and we ?nd a sign of non-relativisic duality really works
Measurement of the B-Tagging Efficiency in the CMS Experiment with the First LHC Collisions
, Ph.D. Dissertation Sharif University of Technology ; Ardalan, Farhad (Supervisor)
Abstract
Jets originating from bottom (b) quarks, play an important role in the study of Standard Model processes together with the search for new physics. In the CMS experiment a considerable e?ort is dedicated to the development and the performance study of so-called b-tagging algorithms. On the other hand, the top quark which is produced in pair (tt¯) with a high rate at the LHC, decays near 99% of the time to a b-quark. Hence it provides a rich source of b-quark jets, suitable for b-jet identi?cation studies. In this thesis, a fully data-driven method to measure the b-tagging e?ciency, using top quark events in its semi-electron ?nal state, is developed. The results of the application of the...
Laminar premixed V-shaped flame response to velocity and equivalence ratio perturbations: Investigation on kinematic response of flame
, Article Scientia Iranica ; Volume 18, Issue 4 B , 2011 , Pages 913-922 ; 10263098 (ISSN) ; Farshchi, M ; Sharif University of Technology
2011
Abstract
The response of a rod-stabilized, V-shaped, premixed flame to upstream velocity and equivalence ratio perturbations was characterized as a function of excitation frequency. The response of the flame to equivalence ratio perturbations was calculated, assuming that the heat release response is controlled by contributions from three disturbances. These disturbances include flame speed, heat of reaction and flame area. Using an analytical model, based on linearization of the front tracking equation for inclined flames, the kinematics of a V-flame anchored on a central obstacle was investigated and its response was compared with that of a conical flame. The results suggest that the phase response...
Investigation of Magnetic and Electromagnetic Methods in Electron Beam Shaping and their Scaling Behavior for Nanometric field Emitters
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bizhan (Supervisor)
Abstract
Nowadays electron beams have extensive applications in electon-optic devices such as microwave devices, electron microscopes and flat displays. So shaping and confinment of electron beams is of great importance. In the other hand, scaling of electron emitters to atomic limit causes new chalanges in reliability and beam shaping. Designing electron optic devices for nanoscale emitters needs great knowledge regarding materials properties and electron optic systems behavior in nano scale. In this study, beside providing basic optics of electron beam and effects Of external electronmagnetic fields, properties of electron optical devices
Considering nano scale limitations is considered. In...
Considering nano scale limitations is considered. In...
Investigations on Stability of Premixed Flames in Turbine Engines
, Ph.D. Dissertation Sharif University of Technology ; Farshchi, Mohammad (Supervisor)
Abstract
This thesis is a complementary experimental and theoretical investigation on stability of premixed flames and a study of combustion instability and combustion dynamics in a swirl-stabilized combustor, aiming to understand the fundamental mechanisms responsible for combustion oscillations in gas turbine combustors. Theoretical investigations on acoustic modeling of a simple combustor and a study on kinematic response of premixed flames to flow perturbations have been discussed in the first part of this work. In another part of thesis, experimental studies on the response of premixed flames to acoustic perturbations have been performed. In addition, experimental investigations on combustion...
Magnetic Monopole with Electric Charge And Holography
, Ph.D. Dissertation Sharif University of Technology ; Ardalan, Farhad (Supervisor)
Abstract
In this thesis at ?rst, we review the magnetic monopole with andwithout electric charge in the ?at and also in the curved space and wereview the multimonopoles with axial and crystalline symmetry. In thisthesis also we review the holography principle and AdS/CFT duality andthe holographic renormalization. as the main part of the thesis the Julia-Zee dyon is studied in the context of AdS/CFT correspodence. We showthat for a solution of the dyon, the scalar ?eld in the model plays the roleof an order parameter. At high temperatures the vacuum expectationvalue of the dual scalar operator is zero and by lowering the temperature,it becomes nonzero and dual ?eld theory experiences a phase...
On the mass spectrum of noncommutative schwinger model in euclidean ℝ2 space
, Article European Physical Journal C ; Volume 71, Issue 4 , April , 2011 , Pages 1-13 ; 14346044 (ISSN) ; Ghasemkhani, M ; Sadooghi, N ; Sharif University of Technology
2011
Abstract
The mass spectrum of noncommutative QED in two-dimensional Euclidean ℝ2 space is derived first in a perturbative approach at one-loop level and then in a nonperturbative approach using the equivalent bosonized noncommutative effective action. It turns out that the mass spectrum of noncommutative QED in two dimensions reduces to a single non-interacting meson with mass Mγ = g/√π, as in commutative Schwinger model
New correlation for natural convection of finned tube A-type air cooler
, Article Applied Thermal Engineering ; Volume 25, Issue 17-18 , 2005 , Pages 3053-3066 ; 13594311 (ISSN) ; Davani, N ; Ardalan, P ; Sharif University of Technology
2005
Abstract
The temperature distribution in a finned tube bundle of an A-type air cooler is investigated. The heat transfer is governed by natural convection. By using a special steam condenser the effect of steam pressure on temperature fields formed outside the bank of finned tubes is studied. It is found that the distribution is approximately the same at various pressures with minor differences. The effects of two-phase flow on temperature distribution are also considered. All 3D temperature contours show maximum values, which highly depend on steam pressures. Moreover, asymmetric steam feeding and probable fouling inside the tubes are possible causes of contour shapes. The experimental Nusselt...
Gauge Symmetry in Renormalization Group Flow
, Ph.D. Dissertation Sharif University of Technology ; Ardalan, Farhad (Supervisor)
Abstract
Exact Renormalization Equations (ERGE) are powerful non-perturbative tools to study the dynamics of Quantum Field theories, with respect to the change of energy. Putting cut-off on momentums of the system, is the specific regularization that is used to obtain ERGEs. This regularization breaks the gauge symmetry in the case of gauge theories. So the symmetry will be lost through the energy flow as well.Finding a gauge symmetry for a regularized system is the aim of this research. Also we have investigated the related ERGEs and the behavior of symmetry through the flow
The impacts of aqueous ions on interfacial tension and wettability of an asphaltenic-acidic crude oil reservoir during smart water injection
, Article Journal of Chemical and Engineering Data ; Vol. 59, issue. 11 , 2014 , pp. 3624-3634 ; ISSN: 00219568 ; Ayatollahi, S ; Riazi, M ; Sharif University of Technology
2014
Abstract
The use of adjusted/optimized saline water categorized into two different classes namely smart water (SW) and low salinity (LoSal) water injection has been proposed for more oil recovery from specific types of oil reservoirs. There are possible mechanisms concerning SW flooding that have been proposed in the literature, some of them are still subject to more examination. In this study, an experimental investigation is performed to determine the influence of type and amount of salt to the surface properties including interfacial tension (IFT) and contact angle (CA) of aqueous solution + acidic and asphaltenic crude oil + carbonate rock systems. For this purpose, the concentration of different...
Investigation of oil recovery and CO2 storage during secondary and tertiary injection of carbonated water in an Iranian carbonate oil reservoir
, Article Journal of Petroleum Science and Engineering ; Volume 137 , 2016 , Pages 134-143 ; 09204105 (ISSN) ; Ayatollahi, S ; Riazi, M ; Sharif University of Technology
Elsevier
2016
Abstract
Gas injection process for more oil recovery and in particular CO2 injection is well-established method to increment oil recovery from underground oil reservoirs. CO2 sequestration which takes place during this enhanced oil recovery (EOR) method has positive impact on reducing the greenhouse gas emission which causes global warming. Direct gas injection into depleted oil reservoirs, encounters several shortcomings such as low volumetric sweep efficiency, early breakthrough (BT) and high risk of gas leakage in naturally fractured carbonate oil reservoirs. Carbonated water injection (CWI) has been recently proposed as an alternative method to alleviate the problems associated with gas...
Mechanistic study on the dynamic interfacial tension of crude oil + water systems: Experimental and modeling approaches
, Article Journal of Industrial and Engineering Chemistry ; Volume 35 , 2016 , Pages 408-416 ; 1226086X (ISSN) ; Ayatollahi, S ; Riazi, M ; Sharif University of Technology
Korean Society of Industrial Engineering Chemistry
2016
Abstract
This study investigates dynamic interfacial tension (DIFT) of acidic crude oil (ACO) and non acidic/basic crude oils (BCO) + deionized water (DW) as a function of pressure from 500 to 4000 psi, and temperature from 30 to 80 °C using an axisymmetric drop shape analysis (ADSA) technique. DIFTs are also modeled using dynamic adsorption model, mono-exponential decay model, and empirical equations. The results showed that if a reduction in the surface excess concentration due to increasing temperature overlooks the total entropy of the molecules in the system, an increase in IFT would be expected
Mechanistical study of effect of ions in smart water injection into carbonate oil reservoir
, Article Process Safety and Environmental Protection ; Volume 105 , 2017 , Pages 361-372 ; 09575820 (ISSN) ; Ayatollahi, S ; Riazi, M ; Sharif University of Technology
Institution of Chemical Engineers
2017
Abstract
The concerns for water availability, affordability and environmental consideration have motivated more research on the development of smart water injection for enhanced oil recovery process. Although wettability alteration has been considered as the dominant mechanism, there is an ample space in this area needs to be explored more. Therefore, a systematic series of experiments is designed and performed to examine the effect of salinity and ion type on the wettability of the carbonate rock surface to find the active mechanisms. For this purpose, the concentrations of different salts including NaCl, KCl, CaCl2 and MgCl2 are examined during 10 days of soaking for salts concentrations range of...