Modification of TTL-1 Thermo hydraulic Test Loop for Study of SB-LOCA in Low Pressure and Temperature Conditions

, M.Sc. Thesis Sharif University of Technology Taherzadeh Fard, Morteza (Author) ; Vosoughi, Naser (Supervisor) ; Jafari, Jalil (Supervisor)

Abstract

In this thesis, TTL-1 thermo hydraulic test loop which was constructed in the Nuclear Science and Technology Research Institute (NSTRI) has been modified. These modifications include changing core section from one fuel rod to a fuel assembly with triangular arrangement, adding a pressurizer on the hot leg of loop, an accumulator, LOCA valve and installation of new sensors for upgrading of data acquisition system and modification of loop piping design. By these modifications, we will able to study different accidents such as LOHA, LOFA and LOCA and validate nuclear thermo hydraulic codes. Moreover, this new thermo hydraulic test loop (TTL-2) has been modeled by RELAP5/MOD3.2 in order to...

Modeling of Two Phase Flow in Porous Media with Heat Generation

, Ph.D. Dissertation Sharif University of Technology Taherzadeh Fard, Morteza (Author) ; Saidi, Mohammad Saeed (Supervisor) ; Ghofrani, Mohammad Bagher (Co-Advisor)

Abstract

The main purpose of this work is investigation of coolability of a boiling debris bed. The main governing equations are derived using volume averaging technique. From this technique some specific interfacial areas between phases are appeared and proper relations for modeling these areas are proposed. Using these specific areas, a modification for the Tung/Dhir model in the annular flow regime is proposed. The proposed modification is validated and the agreements with experimental data are good. Finally, governing equations and relations are implemented in the THERMOUS program to model two-phase flow in the debris bed in the axisymmetric cylindrical coordinate. Two typical configurations...

Surface Waves Propagation in a Piezoelectric/Piezomagnetic Half Space Overlaid With a Finnite Layer

, M.Sc. Thesis Sharif University of Technology Soltanian Fard, Mohammad Amin (Author) ; Skandari, Morteza (Supervisor)

Abstract

The propagation of the surface waves in the piezoelectric (PE) and piezomagnetic (PM) layered media are studied. The surface BG waves in the PE half-spaces overlaid by a layer are considered and the closed-form dispersion relations for the open and short electromechanical surface boundary conditions are obtained. The numerical results for the phase velocities and the electromechanical coupling factor for PZT-2 and PZT-8 media are presented. Furthermore, the propagation of the Rayleigh waves in the PE-PM layered media is considered. The effects of the imperfect bonding between the half-space and the layer are discussed. Later, we study the propagation of the Rayleigh waves in 4 different...

Modeling of two-phase flow in porous media with heat generation

, Article International Journal of Multiphase Flow ; Volume 69 , March , 2015 , Pages 115-127 ; 03019322 (ISSN) Taherzadeh, M ; Saidi, M. S ; Sharif University of Technology

Elsevier Ltd 2015

Abstract

The main purpose of this work is investigation of coolability of a boiling debris bed. The main governing equations are derived using volume averaging technique. From this technique some specific interfacial areas between phases are appeared and proper relations for modeling these areas are proposed. Using these specific areas, a modification for the Tung/Dhir model in the annular flow regime is proposed. The proposed modification is validated and the agreements with experimental data are good. Finally, governing equations and relations are implemented in the THERMOUS program to model two-phase flow in the debris bed in the axisymmetric cylindrical coordinate. Two typical configurations...

Modified Lignin Natural Polymer and Graphene Oxide Aerogels and Valuation of their Performance in Sample Preparation

, M.Sc. Thesis Sharif University of Technology Taherzadeh, Mehrnoush (Author) ; Bagheri, Habib (Supervisor)

Abstract

A green aerogel was prepared by synthesizing amine-modified lignin from sugarcane bagasse and further modification by CS2 and subsequent freeze drying. This aerogel was implemented as an extractive phase in a home-made online micro solid phase extraction-high performance liquid chromatography (μSPE-HPLC) setup for analyzing cardiovascular drugs (valsartan and losartan) in urine samples. To study the effect of functionalization, bare or functionalized lignin powders were mixed with graphene oxide (GO) at different ratios while functionalized lignin showed the highest efficiency. The prepared aerogel was analyzed using CHNS elemental analysis, and FT-IR spectrometry. Effects of influencing...

Preparation of amine–modified lignin and its applicability toward online micro–solid phase extraction of valsartan and losartan in urine samples

, Article Journal of Chromatography A ; Volume 1643 , 2021 ; 00219673 (ISSN) Taherzadeh Ghahfarrokhi, M ; Zeinali, S ; Bagheri, H ; Sharif University of Technology

Elsevier B.V 2021

Abstract

In the present work, with the focus on an environmentally–friendly approach, some gels were prepared by synthesizing amine–modified lignin, extracted from sugarcane bagasse, and further esterification and subsequent freeze–drying. These lignin–based gels were implemented as extractive phases in an online micro–solid phase extraction (μSPE) setup in conjunction with high performance liquid chromatography (HPLC) with UV detector. The developed method was used for analytical determination of valsartan and losartan in urine samples. To study the effect of the functionalization process, the efficiency of the unmodified lignin and the functionalized lignin were compared both in the absence and the...

Experimental study of small and medium break LOCA in the TTL-2 thermo-hydraulic test loop and its modeling with RELAP5/MOD3.2 code

, Article Scientia Iranica ; Volume 17, Issue 6 B , NOVEMBER-DECEMBER , 2010 , Pages 492-501 ; 10263098 (ISSN) Taherzadeh, M ; Jafari, J ; Vosoughi, N ; Arabnezhad, H ; Sharif University of Technology

2010

Abstract

Small and medium break LOCA accidents at low pressure and under low velocity conditions have been studied in the TTL-2 Thermo-hydraulic Test Loop, experimentally. TTL-2 is a thermal hydraulic test facility which is designed and constructed in NSTRI to study thermal hydraulic parameters under normal operational and accident conditions of nuclear research reactors. A nodalization has been developed for the TTL-2 and experimental results have been compared with RELAP5/MOD3.2 results. The considered accidents are a 25% and 50% cold leg break without emergency core cooling systems. Results show good agreement between experiments and RELAP5/MOD3.2 results. This research provides experimental data...

Impact of Stress on Permeability of Packed Hydraulic Fracture

, M.Sc. Thesis Sharif University of Technology Taherzadeh, Dadbeh (Author) ; Shad, Saeed (Supervisor) ; Fatemi, Mobeen ($item.subfieldsMap.e)

Abstract

Given the broad role of oil and gas playing in the world economy, finding the hydrocarbon reservoir that economically is affordable is quite significant. Some of the unconventional oil and gas reservoirs are important from the economic point of view since they produce insufficient hydrocarbon due to either low permeability or damage during drilling and production. Hydraulic fracturing is one of the most significant methods for improving the productivity of wells and reservoirs. Hydraulic fracturing acts by affecting on reservoir rock physic. In the current century, this approach has an essential effect in enhancing the permeability and production of reservoirs by creating, extending and...

Conditions on Fractional-order LTI Systems to be Negative Imaginary

, M.Sc. Thesis Sharif University of Technology Neshat Taherzadeh, Khashayar (Author) ; Tavazoei, Mohammad Saleh (Supervisor)

Abstract

In this thesis, we derive the analytic condition that linear time invariant fractional order system being positive real. Also, by inspiration of positive real condition, we derive the analytic condition for linear time invariant fractional order system that their imaginary part of frequency response being negative. Intended conditions for single input single output systems are derived in the form of necessary conditions in one way and derived in the form of sufficient conditions in another way. However, intended conditions in multiple input multiple output are just derived in the form of sufficient conditions. Furthermore, an upper band for phase of oustaloup approximation frequency response...

Ant colony algorithm for the shortest loop design problem [electronic resource]

, Article Computers and Industrial Engineering, Elsevier ; Volume 50, Issue 4, August 2006, Pages 358–366 Eshghi, K. (Kourosh) ; Kazemi, Morteza ; Sharif University of Technology

Abstract

In this paper, a new algorithm for solving the shortest loop design problem is presented. The shortest loop design problem is to find the shortest loop for an automated guided vehicle covering at least one edge of each department of a block layout. In this paper, first it is shown that this problem can be represented as a graph model. The properties of the presented model enable us to design a meta-heuristic based on ant colony system algorithm for solving the shortest loop design problem. Computational results show the efficiency of our algorithm in compare to the other techniques

A nonlinear feed-forward memory-less model to fast prediction of threshold voltage in junction-less double-gate MOSFETs

, Article International Journal of Numerical Modelling: Electronic Networks, Devices and Fields ; Volume 34, Issue 1 , 2021 ; 08943370 (ISSN) Annabestani, M ; Nasserian, M ; Hasanzadeh, F ; Taherzadeh Sani, M ; Hassanzadeh, A. R ; Sharif University of Technology

John Wiley and Sons Ltd 2021

Abstract

Decreasing Drain-Induced-Barrier-Lowering (DIBL) is one of the nondesirable short-channel effects, causes the threshold voltage of the transistor to be reduced by increasing the drain voltage. DIBL makes it impossible for engineers to consider VT as a constant, and it is necessary to calculate VT as a function of the drain voltage. Therefore, to consider the DIBL effect in the design of ICs, a large computational burden is imposed on the system, which slows down the simulation process in circuit-level simulators. Accordingly, a Nonlinear Feed-Forward Memory-Less (NFFML) model using the Gram-Schmidt orthogonalization approach is proposed, which calculates the VT of the new generation of...

Modeling Reaction and Distribution of Water in Nanopores of the Cathode Catalyst Layer of PEM Fuel Cell

, M.Sc. Thesis Sharif University of Technology Nushak, Fatemeh (Author) ; baghalha, morteza (Supervisor)

Abstract

In the proton exchange membrane fuel cells (PEM, the produced water would be divided into two phases of vapor and liquid. distribution of both liquid and vapor phases in different cell layers affects the performance, the efficiency and the life of a fuel cell significantly. Moreover, Nano pores of the cathode catalyst layer are involved with some phenomena such as electrochemical reaction kinetics, heat and mass transfer and interface phase change. One of the most important problems in the performance of fuel cells is distribution of liquid water in the porous areas. Water flooding in fuel cells causes to delay in oxygen transport to active sites in the catalyst layer because the pores of...

Love Wave Propagation in a Functionally Graded Magneto-Electro-Elastic Half-Space with Quadratic Variations

, M.Sc. Thesis Sharif University of Technology Nobahar, Masoud (Author) ; Eskandari, Morteza (Supervisor)

Abstract

The propagation behavior of Love wave in functionally graded magneto-electro-elastic half-spaces with a quadratic variation is addressed. The magneto-electromechanical coupling factor, the dispersion relations, electric potential, magnetic potential and displacement are obtained analytically for both magneto-electrically open and short conditions. The effect of gradient coefficient on phase velocity, group velocity and magneto-electromechanical coupling factor are plotted and discussed. Research on the wave propagation in magneto-electro-elastic materials is still very limited. This work provides us with a theoretical foundation to design and practically apply SAW devices with high...

Elastic Analysis of a Surface Stiffened Transversely Isotropic Half-space Under a Buried Horizontal Point Load

, M.Sc. Thesis Sharif University of Technology Naghib, Hamed (Author) ; Eskandari, Morteza (Supervisor)

Abstract

In this study, the interaction between thin plate completely bonded to the transversely isotropic halfspace and a concentrated force applied horizontally (Mindlin-type force) are considered. This problem has been solved analytically. This problem is used as sample for thin solid films and surface coating technology, where the surface of solid is covered by thethin plate for increasing its stiffness. Moreover, this problem is a good sample when homogenous solid is subjected to contact loading and can be seen that mechanical properties of material which is near the solid surface varies; consequently, a two-phase solid is created.Because of the influence of noted inhomogeneity, solid is...

Modeling and Simulation of the Catalyst Regeneration Process of FCC Unit of Abadan Refinery

, M.Sc. Thesis Sharif University of Technology Loni, Zahra (Author) ; Baghalha, Morteza (Supervisor)

Abstract

Hydrodynamics plays a crucial role in defining the performance of fluidized beds. The numerical simulation of fluidized bed is very important in the prediction of its behaviour. From this point of view, in the present study a dynamic two dimensioanl model is developed for the modeling of regenerator system of a UOP fluid catalytic cracking (FCC) unit of Abadan refinery with a high-efficiency regenerator. Of the various modeling and simulation techniques, computational fluid dynamics (CFD) is employed in this thesis. Effects of gas velocity, the transient local solid volume fraction, pressure drop for gas and solid phase, solid holdup distribution and solid circulation pattern have been...

Secure- multiparty Computation Protocol for Privacy Preserving Data Mining

, M.Sc. Thesis Sharif University of Technology Maftouni, Mahya (Author) ; Amini, Morteza (Supervisor)

Abstract

Privacy preserving data mining helps organizations and companies not only to deal with privacy concerns of customers and regular limitations, but also to benefit from collaborative data mining. Utilizing cryptographic techniques and secure multiparty computation (SMC) are among widely employed approaches for preserving privacy in distributed data mining. The general purpose of secure multiparty computation protocols to compute specific functions on private inputs of parties in a collaborative manner and without revealing their private inputs. Providing rigorous security proof of secure multiparty computation makes it a good choice for privacy preservation, despite of its cryptographic...

Information-flow Analysis in Android Apps for Protecting User Privacy

, M.Sc. Thesis Sharif University of Technology Barkhordari, Alireza (Author) ; Amini, Morteza (Supervisor)

Abstract

The rapid growth of Android operating system alongside its open-source nature has made it as the most popular operating system of mobile devices. On the other hand, regarding the increasing computational power of mobile devices, a wide variety of applications are coming to this type of devices. Meanwhile unfortunately many malicious softwares trying to keep up with other applications, are targeting this popular operating system. Therefore with regard to the fact that this type of devices usually store private and sensitive information of their users, security of mobile operating systems is considered very important. Having this matter in mind, the goal of this research work has been...

Analysis of Slabs Stiffened by Cables and Pedestals

, M.Sc. Thesis Sharif University of Technology Mokhberi, Arsalan (Author) ; Eskandari, Morteza (Supervisor)

Abstract

In this study, a new concrete slab stiffened by concrete pedestals and steel cables is introduced. The slab system is studied by employing both analytical and numerical methods. The steel cables are connected to the edges of slab and the concrete pedestals mounted at the bottom face of slab act as the middle supports of cables. The tension force in the cable and its inclination results in upward forces acting at the bottom face of slab. With the aims of classical theory of thin plates and the superposition technique, the problem of a simply supported rectangular slab stiffened by cables is studied analytically. The obtained results are verified by a numerical modelling implemented in SAP2000...

Parametric Study of Telescopic Metallic Yielding Dampers

, M.Sc. Thesis Sharif University of Technology Misaghi, Mohammad (Author) ; Eskandari, Morteza (Supervisor)

Abstract

The parametric study of a new introduced metallic yielding damper called telescopic damper is addressed. The telescopic damper comprises of three concentric steel pipes connected together by lead shear keys. The inner and outer steel pipes are subjected to axial loading which results in the shear yielding of the embedded lead cylinders. The inner steel pipe has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Employing ABAQUS software, the behavior of damper under cyclic loading is studied numerically. The finite element model is verified by available results in the literature. The effects of inner and outer steel pipes thickness,...

An Access Control System for Time Series Data in NoSQL Databases

, M.Sc. Thesis Sharif University of Technology Noury, Amir (Author) ; Amini, Morteza (Supervisor)

Abstract

An important class of applications which have been rapidly growing recently is the one that create and use time series data. These types of data sets are ordered based on the timestamps associated to their data items. In practice, traditional relational databases are unable to satisfy the requirements of these data sets; however, NoSQL databases with column-wide data structure are appropriate infrastructure for them. These databases are very efficient in read and write operations (especially for time series data, which are ordered) and are able to store unstructured data. Time series data may contain valuable and sensitive information; hence, they should be protected from the information...