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Simulation of ventilation effects on indoor radon
, Article Management of Environmental Quality ; Volume 24, Issue 3 , 2013 , Pages 394-407 ; 14777835 (ISSN) ; Mahmoudi, J ; Ghanbari, M ; Sharif University of Technology
2013
Abstract
Purpose: The purpose of this paper is to describe the use of computational fluid dynamics (CFD) to simulate indoor radon distribution and ventilation effects. This technique was used to predict and visualize radon content and indoor air quality in a one-family detached house in Stockholm. The effects of intake fans, exhaust fans and doors on radon concentration were investigated. Design/methodology/approach: In this study a mechanically balanced ventilation system and a continuous radon monitor (CRM) were used to measure the indoor ventilation rate and radon levels. In a numerical approach, the FLUENT CFD package was used to simulate radon entry into the building and ventilation effects....
Influence of indoor air conditions on radon concentration in a detached house
, Article Journal of Environmental Radioactivity ; Volume 116 , February , 2013 , Pages 166-173 ; 0265931X (ISSN) ; Mahmoudi, J ; Ghanbari, M ; Sharif University of Technology
2013
Abstract
Radon is released from soil and building materials and can accumulate in residential buildings. Breathing radon and radon progeny for extended periods hazardous to health and can lead to lung cancer. Indoor air conditions and ventilation systems strongly influence indoor radon concentrations. This paper focuses on effects of air change rate, indoor temperature and relative humidity on indoor radon concentrations in a one family detached house in Stockholm, Sweden.In this study a heat recovery ventilation system unit was used to control the ventilation rate and a continuous radon monitor (CRM) was used to measure radon levels. FLUENT, a computational fluid dynamics (CFD) software package was...
An analytical approach to determination of bending modulus of a multi-layered graphene sheet
, Article Thin Solid Films ; Volume 496, Issue 2 , 2006 , Pages 475-480 ; 00406090 (ISSN) ; Seifi, P ; Naghdabadi, R ; Ghanbari, J ; Sharif University of Technology
2006
Abstract
In this paper, the bending modulus of a multi-layered graphene sheet is investigated using a geometrically based analytical approach. For this purpose, a bending potential energy is derived, based on the van der Waals interactions of atoms belonging to the two neighboring sheets of a double-layered graphene sheet. The inter-atomic spacing between the adjacent layers is determined along the line of action of the applied bending moments. The bending potential of the double-layered sheet is calculated by summing up the potentials at discrete hexagons over the length and width of the sheet. A multi-layered graphene sheet is considered as consisting of many stacking double-layers. It is observed...
Study of Supramolecular Chemistry of Fullerene (C60) with Azobenzene Tweezer Linking to Biaza-Crown Macrocycles Coordinated to Zinc Tetraphenylporphyrin
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
In this project, in continuation of a PhD resreach undertaken in this research group in 2017, the synthesis and study of two new tweezer and linker molecule bearing azobenzene moiety were carried out, characterized by applying IR spectroscopy, ¹H and ¹³C {¹H} NMR, fluorescence spectroscopy, UV-visible spectroscopy, elemental analysis and X-ray crystallography. Firstly, interaction of T2 with meso-tetraphenylporphyrinato zinc(II) and aluminium tetraphenylporphyrinato were studied using the fluorescence spectroscopy. The formation constant of T2 in cis and trans isomer with ZnTPP was measured as 5.1(±0.4) ×108 and 2.0×108(±1074) dm6mol-2, respectively. The formation constant of T2 in with...
Wavelet domain binary partition trees for semantic object extraction
, Article Electronics Letters ; Volume 43, Issue 22 , 2007 , Pages 1189-1191 ; 00135194 (ISSN) ; Woods, J. C ; Rabiee, H. R ; Lucas, S. M ; Sharif University of Technology
2007
Abstract
The novel generation of binary partition trees inside the wavelet domain is presented, where spatial frequency is used in conjunction with colour to produce a threshold free tree for segmentation. The method forces objects to reside inside single branches of the tree by constraining their development using multi-dimensional descriptors. © The Institution of Engineering and Technology 2007
Wavelet domain binary partition trees for image segmentation
, Article 2008 International Workshop on Content-Based Multimedia Indexing, CBMI 2008, London, 18 June 2008 through 20 June 2008 ; 2008 , Pages 302-307 ; 9781424420445 (ISBN) ; Woods, J. C ; Rabiee, H. R ; Lucas, S. M ; Sharif University of Technology
2008
Abstract
When performing segmentation using tree based representations it is evident that contiguous objects are often dispersed widely across the tree making controlled selection difficult. This paper demonstrates robust segmentation by the generation of Binary Partition Trees entirely within the wavelet domain. By using spatial frequency in conjunction with colour, a threshold free tree is produced which compels objects to reside inside single branches of the tree by constraining their merging development. Experimental results show the superior performance of the proposed algorithm compared to the existing colour based BPT algorithms. ©2008 IEEE
Synthesis of Azacrown Ethers N2O2 Ligands Substituted on the Ullerene and Investigation of Its Coordination Properties
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
The goal of this project was study on coordination behavior of the 14-membered macrocyclic ligand of type N2O2 aza-crown while it is attached to fullerene C60 nano-particle. For this purpose, firstly the macrocyclic ligand (Fig 3-1, L1) was synthesized and then was reacted with C60 (Fig 3-1, L2) of which the product was characterized by elemental analysis. Since the product was insoluble in any solvents, further study on its coordination chemistry was impossible. In a second procedure, the macrocyclic ligand was reacted with benzylbromide. The reaction mixture gave two macrocyclic ligands with different number of benzylic pendant groups (Fig 3-1, L3-L4). The products were separated by column...
Incremental Learning Approach in Spam Detection
, M.Sc. Thesis Sharif University of Technology ; Beygi, Hamid (Supervisor)
Abstract
Studies show that a large proportion of sent emails are spam. Spam is one of the major problems of e-mail users that result in wasting time and cost. To overcome this problem different ways are used, one of the best ways is detecting spam based on their contents. Separating legitimate e-mails and spam within their contents can be categorized as text classification. So machine-learning approaches are extremely applied in text classification, that machine-learning algorithms can be used for spam classification. However, in the majority of these algorithms, training phase is in a batch. Whereas using incremental learning algorithms is preferred in many applications, especially spam detections....
Using of Exhaust Gas from Gas Turbine for Conservation of Energy Consumption
, M.Sc. Thesis Sharif University of Technology ; Nouri, Ali (Supervisor)
Abstract
Nowadays, the use of gas turbines with low capacity have acceptance in large quantity. This type of gas turbines with a capacity of approximately 5-200kW are known as microturbines. This type of turbines due to the existence of limitations on increasing of turbine inlet temperature and compressor pressure ratio has low efficiency compared to the turbine with high capacity. Therefore the use of a recuperator in the cycle is necessary. Optimum design of heat recuperator has important effect on improving of gas turbine cycle efficiency. In this project for optimum design of heat recuperator, the effect of recuperator on gas turbine cycle efficiency is studied. By determining geometric...
Comparative Study on [60]Fullerene and Cu(II) Complexation with O2N3-Azacrowns
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
The purpose of this project is to synthesis of O2N3-azacrown ligands with 17 to 21 membered ring and investigation of their interaction with C60 according to increase ring size. These macrocyclic ligands can be used in C60 purification. In this project, change in macrocyclic cavity for finding the best macrocycle with appropriate cavity to C60 size has been considered. Firstly, five O2N3-azacrown ligands were synthesized and characterized by NMR spectroscopy and elemental analysis. Interaction of these ligands were considered by electronic spectroscopy applying Benesi-Hildebrand equation. According to the results, it was found that the best macrocycle for formation of stable complex with...
Synthesis and Electrochemical Study of Endohedral Fullerenes Prepared by Arc Vaporizing Method
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
Fullerenes are molecular solid materials which are composed of 3D closed shell carbon-only structure. As soon as mass production of fullerenes was performed, the synthesis and characterization of endohedral fullerenes having at least one non-carbon element in the hollow fullerene cage, was started (in which about 30 atoms inserted in it so far). Furthermore, because of low efficiency and purity of these nano-particles, nowadays characterization of fullerenes is one of the most important research fields. In this project, we firstly optimized the fullerene production parameters in an arc discharge reactor to reach convenient efficiency. Then, the synthesis of endohedral fullerene by vaporizing...
Improving Video Streaming over Peer-to-Peer Overlay Networks
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Mohammad (Supervisor)
Abstract
Overlay Peer-to-Peer networks opposed to their high scalability and more robustness against network errors, are more considerable rather than other content distribution approaches such as Client/Server and multicast video streaming. At this thesis we investigate the video streaming over these networks, which includes more than half of internet traffic nowadays.Localized video streaming is one of the techniques for improving quality of service (QoS) over peer-to-peer networks. With localization techniques, video chunks distribute among neighbors that have more proximity with each other and traffic is held localized over the network.We proposed a new metric for estimating network proximity of...
(Synthesis and Comparative Study on Complexation of OxNy-Azacrown Macrocyclic Ligands with [60] Fullerene and Cu(II
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
In our previous work in this laboratory, macrocycle containingO_2 N_2 and O_2 N_3- donor set with various ring size were synthesized. The intraction of macrocyles with [60]fullerene were determined. In this research, we synthesized 22-membered aza-crown macrocycle ligand containing O_4 N_2- donor set and characterized by NMRspectroscopy. The intraction of macrocycle with [60]fullerene were also investigated by UV-Visible spectroscopy. The formation constant was determined applying Benesi--Hildebrand equation. The result has been showed that O_4 N_2 macrocyle had better complexation with [60]fullerene in comparision of O_2 N_3 and O_2 N_2 donor sets. Then, the interaction of O_4 N_2 with...
Video Scene Recognition
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Mohammad (Supervisor)
Abstract
Scene classification and understanding is one of the most important fields in computer vision. Its applications are such as exploring robot navigation enviroment, content-based image retrieval (CBIR), organization in image databases, highly semantic describing images and videos and content extraction of videos.Many methods and algorithm are proposed till today to deal with diversity of this field by emphesizing on feature based methods or machine learning based methods. In this research we have focoused on proposing a new algorithm which is using principals of NBNN image classification method but major changes in how to exract distance metric from Nearest neighbour and how to use local...
Synthesis of C60 and Endohedral Fullerenes in New Multi-Channel Arc Reactor Equipped with Horizontal Graphite Electrodes
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram (Supervisor)
Abstract
One of the most common methods of producing fullerenes is electric arc vaporization of graphite. Due to the low yield and purity of the nanoparticles in this method, the synthesis and isolation of the area research is important. In this work, the production was improved in a multi-channel arc reactor in which having horizontal graphite electrodes. The influence of various operational parameters such as pressure of inert gas, spark time, interval time between two sparks, voltage and current were completely optimized. Moreover, the prominent advantage of the new reactor was increasing the number of manufacturing units, at least from one to three, which the production of fullerene was...
Complexity- Rate- Distortion Optimization for Video Compression in H.264/AVC Standard
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Mohammad (Supervisor)
Abstract
As the applications of digital video is becoming elementary parts of our daily life both in entertainment and business, the amount of digital video data being transferred by or stored in PDAs rapidly increases. Despite the fact that H.264/AVC is very efficient in terms of compression efficiency, however it is too complex to be used in devices in which their battery energy is restricted and cannot bear this complexity. In this thesis, a fast mode decision algorithm is proposed which brings into play the correlation in content of the video frames and reduces the number of candidate inter modes to be evaluated.For each macroblock, the proposed method performs two steps: first step attempts to...
Optimal Distributed Generation Allocation and Sizing Considering Operation Indices
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
The need for independent power generation has been increased in recent years with the growing demand in micro grid systems. Losses in power systems are unavoidable. These losses occur in transmission to distributionnetworks from the generation sites to the end-user loads. Reduction of power losses has been one of the reasons for engineers to be attracted by micro grid systems which include small size independent power generation units. However, in a micro grid with several DGs of different types and with all kinds of loads of variable nature, an optimal power balance in the system has to be achieved. This optimal objective, which results in minimal energy losses over a specific period of...
Comparative study on the effect of nitrogen-donor groups versus macro-ring size in O2Nx-azacrowns on the complexation with [60]fullerene
, Article Fullerenes Nanotubes and Carbon Nanostructures ; Vol. 22, issue. 4 , 2014 , pp. 322-331 ; ISSN: 1536383X ; Mahloojy, N ; Sharif University of Technology
2014
Abstract
The interaction of [60]fullerene with a newly synthesized series of 17-to 21-membered macrocyclic ligands containing an O2N3-donor set has been investigated. The formation constants (K) arising from their complexation with [60]fullerene macrocycles, having various ring size, were measured in CHCl3 media by UV-visible spectroscopy applying Benesi-Hildebrand (BH) equation and their stoichiometries were also determined by the Job method. The best K value was measured for 20-membered ring macrocycle in which a 1:1 complexation stoichiometry with [60]fullerene was dominant. Furthermore, 1H NMR spectroscopy data reveled that the macrocylic ligand coordinates [60]fullerene via the nitrogen-donor...
An incremental spam detection algorithm
, Article 2011 International Symposium on Artificial Intelligence and Signal Processing, AISP 2011, 15 June 2011 through 16 June 2011 ; June , 2011 , Pages 31-36 ; 9781424498345 (ISBN) ; Beigy, H ; Sharif University of Technology
2011
Abstract
The voluminous of the e-mails are spam. Several algorithms are represented for spam detection based on batch learning. In this paper, a new algorithm based on incremental learning is introduced. The algorithm composes new knowledge from new training data with previous knowledge by combining classifiers based on weighted majority voting. The experiment results show that the proposed algorithm outperforms other related incremental algorithms and non-incremental algorithms
Order and pole locator estimation in fractional order systems using bode diagram
, Article Signal Processing ; Volume 91, Issue 2 , February , 2010 , Pages 191-202 ; 01651684 (ISSN) ; Haeri, M ; Sharif University of Technology
2010
Abstract
This paper deals with estimation of fractional order and pole locator in fractional order systems. The estimation is based on Bode diagram of the system that is obtained using input and output measurements. Here the magnitude diagram is approximated with number of straight lines depending on the level of complexity and in consequence a very good estimation of fractional order and acceptable approximations of pole locators are determined. Relying on the proposed method, complexity of fractional order system identification which is mostly due to the estimation of fractional order is substantially resolved. Some example simulation results are provided to explain the work and show its...