Design of Low Power Harmonic Rejection Mixer for Wideband Application

, M.Sc. Thesis Sharif University of Technology Jafarpour Dahaghani, Reza (Author) ; Akbar, Fatemeh (Supervisor)

Abstract

The increasing demand for communication bandwidth and limited spectrum availability have heightened the complexity of radio front-end circuits in IoT applications. Achieving spectral efficiency is a key challenge, particularly for IoT devices operating at specific frequency bands such as 315 MHz, 433 MHz, 868 MHz, and 915 MHz.Due to the limited linearity of the transmit path, harmonic distortion components, known as counter intermodulation (CIM) products, are generated. These CIM products can directly fall into the receiver (RX) band or enter it via cross-modulation, thereby degrading the frequency division performance. Additionally, CIM products can interfere with protected bands, violating...

Simulator Development for Thermal Operation (Pre-heating) of SAGD Techniques

, M.Sc. Thesis Sharif University of Technology Jafarpour, Mahshid (Author) ; Pishvaie, Mahmoud Reza (Supervisor) ; Bozorgmehri, Ramin (Supervisor)

Abstract

This work describes the use of a two-dimensional numerical simulator for Steam Assisted Gravity Drainage (SAGD) using the model proposed by Coats et al with some improvements. Despite the Coats model this developed model accounts for capillary and gravity effects in the energy equation with a variable thermal conductivity of the formation. First, a sensitivity analysis is performed for SAGD process. Then, the simulator is used to describe the pre-heating process preceding SAGD. We studied two methods of preheating process and found that there exists an optimum method of preheating for any reservoir. We concluded that longer preheating period does not necessarily yield a faster recovery

Introduction to the world of Quantum Computers

, Article 5th IEEE International Conference on Cognitive Informatics, ICCI 2006, Beijing, 17 July 2006 through 19 July 2006 ; Volume 2 , 2006 , Pages 760-764 Jafarpour, S ; Sharif University of Technology

2006

Abstract

The world is changing very fast, and so are the ways of communication and computation. This article is about a new communication and information technology based on the principles of the quantum physics. At first we discuss about some fundamental paradigms of Quantum Computers World, and then introducing the basis of quantum computation: "QBit". Afterthat we will explain some magic properties of this atomic QBit including Quantum Measurement, Superposition, Entanglement, etc. Then we introduce Quantum Gates the basic modules of the next generation computers. Their relation with the ordinary logical gates and the properties of some of the most useful quantum gates. And finally, we will have a...

Partially asymmetric simple exclusion model in the presence of an impurity on a ring

, Article Journal of Physics A: Mathematical and General ; Volume 33, Issue 9 , 2000 , Pages 1797-1808 ; 03054470 (ISSN) Jafarpour, F. H ; Sharif University of Technology

2000

Abstract

We study a generalized two-species model on a ring. The original model (Mallick K 1996 J. Phys. A: Math. Gen. 29 5375) describes ordinary particles hopping exclusively in one direction in the presence of an impurity. The impurity hops with a rate different from that of ordinary particles and can be overtaken by them. Here we let the ordinary particles also hop backward with rate q. Using the matrix product ansatz we obtain the relevant quadratic algebra. A finite-dimensional representation of this algebra enables us to compute the stationary bulk density of the ordinary particles, as well as the speed of impurity on a set of special surfaces of the parameter space. We will obtain the phase...

Exact solution of an exclusion model in the presence of a moving impurity on a ring

, Article Journal of Physics A: Mathematical and General ; Volume 33, Issue 48 , 2000 , Pages 8673-8680 ; 03054470 (ISSN) Jafarpour, F. H ; Sharif University of Technology

2000

Abstract

We study a recently introduced model by Arndt et al which consists of positive and negative particles on a ring. The positive (negative) particles hop clockwise (anticlockwise) with unit rate and oppositely charged particles may swap their positions with asymmetric rates q and unity. In this paper we assume that a finite density of positively charged particles ρ and only one negative particle (which plays the role of an impurity) exist on the ring. It turns out that the canonical partition function of this model can be calculated exactly using matrix product ansatz formalism. In the limit of infinite system size and infinite number of positive particles, we can also derive exact expressions...

Effect of Carbon Nanoparticle Hybrid on the Properties of Styrene-Butadiene Rubber (SBR)

, M.Sc. Thesis Sharif University of Technology Jafarpour, Erfan (Author) ; Shojaei, Akbar (Supervisor)

Abstract

Flexible polymers (elastomers) are especially suitable for dynamic applications, and carbon fillers are well-known filler for elastomers. These are widely used in elastomer matrices for various commercial applications. Some of carbon nano fillers like Nano Diamond cannot impart such high degree of reinforcement to polymer matrices mainly because of improper filler dispersion and lack of strong filler-polymer interaction. In this effort, we examine the effects of two different nanostructured carbons when they are incorporated in a rubber matric in terms of mechanical, thermal and electrical properties of the nanocomposites. Different ingredients and hybrid nanofillers were added to matric by...

Short Time Effect of Auxetic Shoe on Kinematics and Kinetics of Vertebral Column During Drop Vertical Jump

, M.Sc. Thesis Sharif University of Technology Rahmani Dahaghani, Mostafa (Author) ; Nourani, Amir (Supervisor) ; Arjmand, Navid (Supervisor)

Abstract

Investigating the influence of shoes on variables of human biomechanics is of a high importance. The purpose of this study was to examine the effect of auxetic Nike Free RN shoe on kinematics and kinetics of human body. It was asked from 11 healthy male to perform drop vertical jump in three conditions: with auxetic Nike Free RN, with conventional shoe and barefoot. 3D Cartesian positions of the markers, which were stuck to the subjects’ bodies, were recoeded using Vicon camera system. Ground reaction force and its center of pressure of each foot captured using two force plates. Moreover, activation of rectus abdominis, longissimus, iliocostalis lomburom and multifidus were recorded using...

High-performance styrene-butadiene rubber nanocomposites based on carbon nanotube/nanodiamond hybrid with synergistic thermal conduction characteristics and electrically insulating properties

, Article Polymer ; Volume 196 , 20 May , 2020 Jafarpour, E ; Shojaei, A ; Ahmadijokani, F ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

Reinforcement of rubbery materials with carbon nanotube (CNT) has gained much attention over the last few decades due to the inherent ability of CNT to improve the physical and mechanical properties of polymer composites. However, CNT renders electrical conductivity to the rubber composites, which could be problematic for a number of applications. In an attempt to overcome such issues, we controlled the insulating properties of styrene-butadiene rubber (SBR) nanocomposites by hybridization of CNT with nanodiamond (ND) particles without scarifying desirable features of the nanoparticles. In this respect, the effects of carbon nanotube (CNT) and nanodiamond (ND), either individually or in...

Design and synthesis of AKAM: A RISC asynchronous microprocessor

, Article 2007 International Conference on Intelligent and Advanced Systems, ICIAS 2007, Kuala Lumpur, 25 November 2007 through 28 November 2007 ; 2007 , Pages 1318-1323 ; 1424413559 (ISBN); 9781424413553 (ISBN) Mirza Aghatabar, M ; Rasooli, A ; Jafarpour, B ; Sharif University of Technology

2007

Abstract

Asynchronous microprocessors are more flexible to adapt to physical parameters, and have lower power consumption than synchronous microprocessors. In this paper we will introduce the design of an asynchronous microprocessor (V8-uRISC) and explore its design process compared to synchronous design. The processor is synthesized by Persia, an automatic tool for synthesizing asynchronous circuits. We have performed full functional test at various levels of design and synthesis. Our results show that an area overhead is expected for the asynchronous design as the cost for lower power and more robustness. ©2007 IEEE

Performance optimization of polymeric porous membrane-based liquid desiccant air dehumidifier used in air conditioning system

, Article International Journal of Energy and Environmental Engineering ; Volume 11, Issue 1 , December , 2020 , Pages 55-71 Jafarpour, A. M ; Fazelpour, F ; Mousavi, S. A ; Sharif University of Technology

Springer 2020

Abstract

In this study an experimental design was developed to optimize the performance and structure of a membrane-based parallel-plate liquid desiccant dehumidifier used in air conditioning regeneration system which operates under high humidity weather conditions. We conducted a series of polymeric porous membranes with different compositions fabricated that were prepared with various weight percentages of polysulfone (PSU), mixed with N-methyl-2-pyrrolidone (NMP) and dimethyl form amide (DMF) solvents. Furthermore, the designed experiments were performed under various operating conditions, indicating that the dehumidification efficiency declines with increasing flow rate, temperature, and...

UV-prepared salep-based nanoporous hydrogel for controlled release of tetracycline hydrochloride in colon

, Article Journal of Photochemistry and Photobiology B: Biology ; Volume 102, Issue 3 , March , 2011 , Pages 232-240 ; 10111344 (ISSN) Bardajee, G. R ; Pourjavadi, A ; Ghavami, S ; Soleyman, R ; Jafarpour, F ; Sharif University of Technology

2011

Abstract

A highly swelling nanoporous hydrogel (NPH) was synthesized via UV-irradiation graft copolymerization of acrylic acid (AA) onto salep backbone and its application as a carrier matrix for colonic delivery of tetracycline hydrochloride (TH) was investigated. Optimized synthesis of the hydrogel was performed by the classic method. The swelling behavior of optimum hydrogel was measured in different media. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA/DTG/DTA). The study of the surface morphology of hydrogels using SEM showed a nanoporous (average pore size: about 350 nm) structure for the sample obtained under...

Improved adsorption performance of ZIF-8 towards methylene blue dye by hybridization with nanodiamond

, Article Journal of Water Process Engineering ; Volume 50 , 2022 ; 22147144 (ISSN) Mirzaei, K ; Mohammadi, A ; Jafarpour, E ; Shojaei, A ; Moghaddam, A. L ; Sharif University of Technology

Elsevier Ltd 2022

Abstract

A series of ZIF-8/OND hybrid nanostructures with different percentages of oxidized nanodiamond (OND) was prepared. Then, the adsorptive removal performance of pristine ZIF-8 and its nanohybrids with OND towards methylene blue (MB) was investigated. The fabricated adsorbents were characterized via thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption, field emission scanning electron microscopy and zeta potential measurements. The maximal adsorption capacity of ZIF-8 (242 mg/g) was found to grow steadily with the increment in OND content and reached an approximate plateau at 343 mg/g for the nanohybrid containing 5 wt% OND, i.e....

An investigation on the influence of highly acidic media on the microstructural stability and dye adsorption performance of UiO-66

, Article Applied Surface Science ; Volume 618 , 2023 ; 01694332 (ISSN) Mirzaei, K ; Jafarpour, E ; Shojaei, A ; Khasraghi, S. S ; Jafarpour, P ; Sharif University of Technology

Elsevier B.V 2023

Abstract

Stability of UiO-66 in 1 M HCl for different exposure times up to 15 days was investigated by employing various characterization techniques such as XRD, FESEM, TEM, TGA, and nitrogen adsorption/desorption. The lower surface area, smaller pore size, and slightly lower thermal stability indicated that the UiO-66 structure experienced a partial breakdown, but could maintain its main structure and showed acceptable stability. In addition, the exposure to the HCl solution added to the missing-linker defects in the structure of UiO-66. The adsorptive performance of HCl-aged UiO-66 nanoparticles towards anionic methyl orange (MO) dye was then evaluated. Compared to as-synthesized UiO-66, maximum...

Photonic band structure of isotropic and anisotropic Abrikosov lattices in superconductors

, Article Physica C: Superconductivity and its Applications ; Volume 467, Issue 1-2 , December , 2007 , Pages 51-58 ; 09214534 (ISSN) Zandi, H ; Kokabi, A ; Jafarpour, A ; Khorasani, S ; Fardmanesh, M ; Adibi, A ; Sharif University of Technology

2007

Abstract

We have performed a numerical solution for band structure of an Abrikosov vortex lattice in type-II superconductors forming a periodic array in two dimensions for applications of incorporating the photonic crystals concept into superconducting materials with possibilities for optical electronics. The implemented numerical method is based on the extensive numerical solution of the Ginzburg-Landau equation for calculating the parameters of the two-fluid model and obtaining the band structure from the permittivity for both orthogonal polarizations, which depends on the above parameters and the frequency. This is while the characteristics of such crystals highly vary with an externally applied...

Photonic band structure of abrikosov lattices in superconductors

, Article Photonic Crystal Materials and Devices VI, San Jose, CA, 22 January 2007 through 25 January 2007 ; Volume 6480 , 2007 ; 0277786X (ISSN) Zandi, H ; Kokabi, A ; Jafarpour, A. A ; Khorasani, S ; Fardmanesh, M ; Adibi, A ; Sharif University of Technology

2007

Abstract

We have performed a numerical solution for band structure of an Abrikosov vortex lattice in type-11 superconductors forming a periodic array in two dimensions for applications of incorporating the photonic crystals concept into superconducting materials with possibilities for optical electronics. The implemented numerical method is based on the extensive numerical solution of the Ginzburg-Landau equation for calculating the parameters of the two-fluid model and obtaining the band structure from the permittivity, which depends on the above parameters and the frequency. This is while the characteristics of such crystals highly vary with an externally applied static normal magnetic field,...

A misbehavior‐tolerant multipath routing protocol for wireless Ad hoc networks [electronic resource]

, Article International Journal of Research in Wireless Systems (IJRWS) ; Vol. 2, Issue 9, pp. , Sep. 2013 Sedghi, H. (Haniyeh) ; Pakravan, Mohammad Reza ; Aref, Mohammad Reza ; Sharif University of Technology

Abstract

Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network...

Analysis and data-based reconstruction of complex nonlinear dynamical systems : using the methods of stochastic processes

, Book Rahimi Tabar, M. Reza

Springer International Publishing 2019

Abstract

This book focuses on a central question in the field of complex systems: Given a fluctuating (in time or space), uni- or multi-variant sequentially measured set of experimental data (even noisy data), how should one analyse non-parametrically the data, assess underlying trends, uncover characteristics of the fluctuations (including diffusion and jump contributions), and construct a stochastic evolution equation?
Here, the term "non-parametrically" exemplifies that all the functions and parameters of the constructed stochastic evolution equation can be determined directly from the measured data.
The book provides an overview of methods that have been developed for the analysis of...

Fabrication and Study of Mechanical Behavior of in Situ Microfibrillar- Reinforced Composites of Polypropylene/Recycled Poly (Ethylene Terephthalate)Toughened with Rubber Particles

, M.Sc. Thesis Sharif University of Technology Motahari, Tayebeh (Author) ; Bagheri, Reza (Supervisor) ; Alizadeh, Reza (Supervisor)

Abstract

The use of polymers is increasing day by day due to low density, reasonable price and ability to produce different products. On the other hand, the accumulation of polymer wastes in nature is one of the environmental concerns in today's world, which is mainly due to the widespread use of polymers in the packaging industry and disposable applications. In order to solve this problem, recycling is recommended as the most appropriate and economical solution. Because in addition to consuming polymer waste, it also saves energy and reduces carbon footprint.Polyethylene terephthalate (PET) is one of the polymeric materials which; It has a special place in the packaging industry and is widely used...

Characterization of Mechanical Properties of Polymer Nanocomposites with Spherical Inhomogeneities

, M.Sc. Thesis Sharif University of Technology Goudarzi, Taha (Author) ; Naghdabadi, Reza (Supervisor) ; Bagheri, Reza (Supervisor)

Abstract

The improved properties of nanocomposites are not achievable with conventional composites. Scale effect is one the most important parameters in the physical and mechanical properties of polymeric nanocomposites. One of the physical phenomena, which can be related to the scale effect, is the very large interface between the nanoparticles and the polymeric matrices. Motional behavior and conformation of polymeric chains change near the nanoparticles surfaces. Due to high interface of the nanoparticles with the polymeric matrices the amount of these types of changes in the polymeric chains are so large that can change the physical and mechanical properties of polymeric nanocomposites. In this...

On small uniquely vertex-colourable graphs and Xu's conjecture [electronic resource]

, Article Discrete Mathematics ; Volume 223, Issues 1–3, 28 August 2000, Pages 93–108 Daneshgar, A. (Amir) ; Naserasr, Reza ; Sharif University of Technology

Abstract

Consider the parameter Λ(G) = |E(G)| - |V(G)|(k - 1) + (k2) for a k-chromatic graph G, on the set of vertices V(G) and with the set of edges E(G). It is known that Λ(G)≥0 for any k-chromatic uniquely vertex-colourable graph G (k-UCG), and, S.J. Xu has conjectured that for any k-UCG, G, Λ(G) = 0 implies that cl(G) = k; in which cl(G) is the clique number of G. In this paper, first, we introduce the concept of the core of a k-UCG as an induced subgraph without any colour-class of size one, and without any vertex of degree k - 1. Considering (k, n)-cores as k-UCGs on n vertices, we show that edge-minimal (k, 2k)-cores do not exist when k ≥ 3, which shows that for any edge-minimal k-UCG on 2k...