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    Dynamic Simulation of Liquid Direct Methanol Fule Cell

    , M.Sc. Thesis Sharif University of Technology Akbarpoor Boroojeni, Behrouz (Author) ; Pishvaei, Mahmood Reza (Supervisor)
    Abstract
    Cell of fuel methanol can store fuel easily, because they can suitable for resources of energy with ambulant applications. As for with the extensive of electrical haul instruments, they attention to the use of fuel cell methanol. In this project a fuel cell methanol consist of different branches such as cathode, Anode, substrates of membrane and influx, has modeled with the form of flat three dimensional. This model consist of ambulant theorems, transfer of mass, chemistry theorems and reflexes of electro chemistry in spongy environment. As for with a little knowledge that is related to the oxidation of methanol, the first research is related to this reflex and the knowledge of mathematic... 

    Resisting Flow Content Characterization in Network Traffic

    , M.Sc. Thesis Sharif University of Technology Momeni Boroojeni, Farzad (Author) ; Kharrazi, Mehdi (Supervisor)
    Abstract
    One way to control the type of data being transferred in the network is to check the header of the packet, but in networks that have high-speed data transmission or data can move through different routes, the probability of finding the first packet which contains the header reduces tremendously, and the usage of the methods mentioned below becomes clear. So even if the packet header isn’t received correctly, or the declarative features of these flows are changed, without having exact knowledge of the data transferred, you can use a limited number of packets to obtain information such as the type and protocol being used. This is possible with the help of statistical data analysis.Traffic... 

    Descriptive Complexity for Counting Problems

    , M.Sc. Thesis Sharif University of Technology Yaghoubi, Omid (Author) ; Ebrahimi Boroojeni, Javad (Supervisor)
    Abstract
    Descriptive complexity refers to the difficulty of expressing a problem in a formal language, allowing for a complete and precise description of the problem, including output specifications for function problems. Despite the success of the descriptive approach in computational complexity, this approach has been predominantly used for decision problems. In contrast to decision problems, a counting problem can be considered as a function with the range of natural numbers. This thesis focuses on the examination of counting problems from a descriptive perspective, exploring the connection between their descriptive and computational versions. Toward this goal, weighted logic is utilized to... 

    A reconfigurable fault-tolerant routing algorithm to optimize the network-on-chip performance and latency in presence of intermittent and permanent faults

    , Article Proceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors ; 2011 , Pages 433-434 ; 10636404 (ISSN) ; 9781457719523 (ISBN) Jabbarvand Behrouz, R ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology
    2011
    Abstract
    As the semiconductor industry advances to the deep sub-micron and nano technology points, the on-chip components are more prone to the defects during manufacturing and faults during system operation. Consequently, fault tolerant techniques are essential to improve the yield of modern complex chips. We propose a fault-tolerant routing algorithm that keeps the negative effect of faulty components on the NoC power and performance as low as possible. Targeting intermittent faults, we achieve fault tolerance by employing a simple and fast mechanism composed of two processes: NoC monitoring and route adaption. Experimental results show the effectiveness of the proposed technique, in that it offers... 

    The controlled release of dexamethasone sodium phosphate from bioactive electrospun PCL/gelatin nanofiber scaffold

    , Article Iranian Journal of Pharmaceutical Research ; Volume 18, Issue 1 , 2019 , Pages 111-124 ; 17350328 (ISSN) Boroojeni, F. R ; Mashayekhan, S ; Abbaszadeh, H. A ; Sharif University of Technology
    Iranian Journal of Pharmaceutical Research  2019
    Abstract
    In this study, a system of dexamethasone sodium phosphate (DEXP)-loaded chitosan nanoparticles embedded in poly-ε-caprolacton (PCL) and gelatin electrospun nanofiber scaffold was introduced with potential therapeutic application for treatment of the nervous system. Besides anti-inflammatory properties, DEXP act through its glucocorticoid receptors, which are involved in the inhibition of astrocyte proliferation and microglial activation. Bovine serum albumin (BSA) was used to improve the encapsulation efficiency of DEXP within chitosan nanoparticles and to overcome its initial burst release. BSA incorporation within the chitosan nanoparticles increased the encapsulation efficiency of DEXP... 

    Effect of Carbon Content on Mechanical Properties of TLP Bonded Ferrite- Martensite Dual Phase Steels

    , M.Sc. Thesis Sharif University of Technology Elyasi Boroojeni, Forood (Author) ; Ekrami, Ali Akbar (Supervisor)
    Abstract
    During the last few years researchers have drawn much attention to HSLA steels because of the application of these steels in many industries. Ferrite-martensite dual phase(DP) steels are one of the most common HSLA steels which are currently used. Combination of these two phases provides good strength along with good ductility. Joining and welding of these steels has always been an important challenge. The aim of this study is to examine applicability of TLP method for joining and dual phase processing of this steels at the same time. Microstructural and mechanical examination of the bonded specimens showed that isothermal solidification occurred during holding for 50 min at the... 

    Releasing All-Pairs Shortest Distances of Public Graphs with Differential Privacy

    , M.Sc. Thesis Sharif University of Technology Tofighi Mohammadi, Alireza (Author) ; Ebrahimi Boroojeni, Javad (Supervisor)
    Abstract
    In the context of differential privacy, a data holder has confidential information about users. The goal is to provide a randomized algorithm that takes this information as input and outputs an aggregation of the input. The algorithm must have the property that for any neighboring input pairs, the output distribution of the algorithm is close. One problem in differential privacy research is the release of shortest distances in a weighted graph. This model, first studied by Adam Sealfon, involves an edge-weighted graph G=(V, E) with weights w : E → R, where the topology of the graph is public and the private information is the weight of the edges. The aim is to provide an (ϵ, δ)-DP algorithm... 

    Algebraic and Combinatorial Bounds for the Hat Guessing Number of Graphs

    , M.Sc. Thesis Sharif University of Technology Shariati, Mohammad Reza (Author) ; Ebrahimi Boroojeni, Javad (Supervisor)
    Abstract
    A number of players are positioned on the vertices of a finite graph, and each is wearing a hat whose color has been randomly and equally likely selected from a finite set of colors. Player A sees Player B if and only if there is a directed edge from the vertex corresponding to A to the vertex corresponding to B. The players must agree on a specific strategy before the game begins and carry it out. Once the game begins, no communication is allowed between the players, and each player must simultaneously guess the color of their own hat. The team wins if at least one guess is correct. For a given directed graph, we define the 'guessing number' of the graph as the maximum number of colors for... 

    Dynamic Modeling and Congestion Control in Computer Networks

    , M.Sc. Thesis Sharif University of Technology Kahe, Ghasem (Author) ; Jahangir, Amir Hossein (Supervisor) ; Ebrahim, Behrouz (Co-Advisor)
    Abstract
    Active queue management (AQM) is a key factor in congestion control and should provide appropriate feedback for flow control in traffic sources to overcome the congestion problem. Beside providing congestion control, achieving predictable queuing delay, maximizing link utilization, simplicity and robustness are also the main objectives of an AQM controller. We propose in this thesis an improved queue dynamic model while incorporating the packet drop probability as well. The proposed model is evaluated using ns2 platform. By applying the improved model, a new compensated proportionalintegral- derivative (PID) AQM controller is developed for TCP network. The time-varying nature of the network... 

    Recovery of Uranium(VI) from UCF Waste by Selective Transportacross Aliquid Membrane

    , M.Sc. Thesis Sharif University of Technology Soltani Behrouz, Masoud (Author) ; Samadfam, Mohammad (Supervisor) ; Fasihi, Javad (Supervisor)
    Abstract
    Due to environmental and economical impacts, recovery of the uranium from nuclear wastes is of continuing interest.This work reports the separation of uranyl ionusing transport technique through chloroform liquid membrane containing a mixture of DBDA15C4 and oleic acidas cooperative carrier.The pH of the feed phase (10-4 M of UO22+) was adjusted with nitric acid and acetic acid/NaOH for pHrange of 2-6.The receiving phase was hydrochloric acid 1M.The organic phase was chloroform which includesthe carrier DBDA15C4 (0.0001 M) and also the oleic acid (0.015M).The results showed that the transport increased with increasing pH and reached to maximumat pH of 5.Maximum cooperative effect of oleic... 

    Conductive nanofiber scaffold for bone tissue engineering

    , Article 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Rasti Boroojeni, F ; Mashayekhan, S ; Abbaszadeh, H. A ; Ansarizadeh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    In order to fabricate nanofiber scaffold for bone tissue engineering, electrospinning technique was employed. This technique produces nanofiberous scaffold supporting cell adhesion, migration, and proliferation. Here, we developed a novel conductive scaffold from poly-caprolactone, gelatin, and poly aniline/graphene nanoparticles. In this study, co-electrospinning was utilized to fabricate composite electrospun scaffold. The effect of polyaniline/graphene (PAG) nanoparticles on the mechanical properties and electrical conductivity of this hybrid scaffold was investigated. The result showed that PAG nanoparticles enbance both mechanical properties and electrical conductivity of the scaffolds.... 

    Some relations between rank of a graph and its complement

    , Article Linear Algebra and Its Applications ; Volume 422, Issue 1 , 2007 , Pages 341-347 ; 00243795 (ISSN) Akbari, S ; Alipour, A ; Ebrahimi Boroojeni, J ; Ghorbani, E ; Mirjalalieh Shirazi, M ; Sharif University of Technology
    2007
    Abstract
    Let G be a graph of order n and rank(G) denotes the rank of its adjacency matrix. Clearly, n ≤ rank (G) + rank (over(G, -)) ≤ 2 n. In this paper we characterize all graphs G such that rank (G) + rank (over(G, -)) = n, n + 1 or n + 2. Also for every integer n ≥ 5 and any k, 0 ≤ k ≤ n, we construct a graph G of order n, such that rank (G) + rank (over(G, -)) = n + k. © 2006 Elsevier Inc. All rights reserved  

    Determination of Optimum Material and Thickness of Filter Based on Radiation Energy in Digital Industrial Radiography (CR) Using MCNP Monte Carlo Simulation Code

    , M.Sc. Thesis Sharif University of Technology Haghizadeh, Cyrus (Author) ; Vosoughi, Naser (Supervisor) ; Rokrok, Behrouz (Supervisor) ; Movafeghi, Amir (Co-Supervisor)
    Abstract
    In this study, the effect of external filter on the various parameters of image quality in digital industrial radiography by CR method for steel and aluminum piece has been investigated. The filter reduces the noise of scattered beams by absorbing the low-energy beams in the X-ray spectrum that are most likely to be scattered, but high filter thicknesses can attenuate the more energetic beams and have a negatively effect on the image quality. On the other hand, the absorption of those low-energy beams increases the average spectrum energy and thus reduce the contrast, so it is necessary to use the appropriate material and thickness of the filter. For this purpose, to examine the filter... 

    Bioinspired nanofiber scaffold for differentiating bone marrow-derived neural stem cells to oligodendrocyte-like cells: Design, fabrication, and characterization

    , Article International Journal of Nanomedicine ; Volume 15 , 2020 , Pages 3903-3920 Boroojeni, F. R ; Mashayekhan, S ; Abbaszadeh, H. A ; Ansarizadeh, M ; Khoramgah, M. S ; Rahimi Movaghar, V ; Sharif University of Technology
    Dove Medical Press Ltd  2020
    Abstract
    Background: Researchers are trying to study the mechanism of neural stem cells (NSCs) differentiation to oligodendrocyte-like cells (OLCs) as well as to enhance the selective differentiation of NSCs to oligodendrocytes. However, the limitation in nerve tissue acces-sibility to isolate the NSCs as well as their differentiation toward oligodendrocytes is still challenging. Purpose: In the present study, a hybrid polycaprolactone (PCL)-gelatin nanofiber scaffold mimicking the native extracellular matrix and axon morphology to direct the differentiation of bone marrow-derived NSCs to OLCs was introduced. Materials and Methods: In order to achieve a sustained release of T3, this factor was... 

    Design and Fabrication of Bioactive Nano Fibrous Scaffold for Central Nervous Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Rasti Boroojeni, Fatemeh (Author) ; Mashayekhan, Shohreh (Supervisor) ; Abbaszadeh, Hojjatollah (Supervisor) ; Hasannejad, Zahra (Co-Advisor)
    Abstract
    A system of electrospun scaffold containing drug-loaded chitosan nanoparticles was introduced for using in spinal cord tissue engineering. In spinal cord injury treatment, the formation of glial scar after injury which contains proteoglycans and activate glial cells should be avoided. In this study, the release of Dexamethasone sodium phosphate (DEXP) as a steroid anti-inflammatory agent from electrospun nanofiber composite containing chitosan nanoparticles was investigated. DEXP is believed to act through its glucocorticoid receptors found in most neurons and glial cells. These receptors’ pathways are involved in the inhibition of astrocyte proliferation and microglial activation....