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    Performance Evaluation of Membrane Bioreactors in Treating Municipal Wastewater

    , M.Sc. Thesis Sharif University of Technology Hatami Bahman Beyglou, Elnaz (Author) ; Torkian, Ayoub (Supervisor)
    Abstract
    Membrane bioreactors can replace the activated sludge process and the final clarification step in municipal wastewater treatment. The combination of bioreactor and crossflow microfiltration allows for a high chemical oxygen demand (COD) reduction of synthetic wastewater. In this study, experimental data from a laboratory scale membrane bioreactor are presented. In order to investigate the influence of various operating parameters such as hydraulic retention time (HRT), biomass concentration and organic loading rate on organic pollutant removal, the pilot scale submerged membrane bioreactor (SMBR) with a Polyvinylidene Fluoride (PVDF) hollow fiber membrane module was conducted using synthetic... 

    Observation of cosmic rays by Alborz -1 array

    , Article Iranian Journal of Physics Research ; Volume 17, Issue 3 , 2017 , Pages 473-484 ; 16826957 (ISSN) Bahman Abadi, M ; Sharif University of Technology
    Isfahan University of Technology  2017
    Abstract
    The first phase of the Alborz Observatory Array (Alborz-1) consists of 20 plastic scintillation detectors each one with surface area of 0.25 m2 spread over an area of 40×40 m2 realized to the study of Extensive Air Showers around the knee at the Sharif University of Technology campus. The first stage of the project including construction and operation of a prototype system has now been completed and the electronics that will be used in the array instrument has been tested under field conditions. In order to achieve a realistic estimate of the array performance, a large number of simulated CORSIKA showers have been used. In the present work, theoretical results obtained in the study of... 

    Single Trial Event Related Potential Extraction Using Tensor Decompositions

    , M.Sc. Thesis Sharif University of Technology Taghi Beyglou, Behrad (Author) ; Shamsollahi, Mohammad Bagher (Supervisor)
    Abstract
    Event related potentials (ERPs), are potentials that arise from the occurrence of an event in the electroencephalogram signals and have very small amplitude compared to the Electroencephalogram (EEG) signal. For that reason, to access ERPs, the experiment is repeated several times under similar conditions and then the are extracted by synchronized averaging, but in this way information such as Amplitude and Delay (Lag) which reflect Mental fatigue and Task habituation of subject is disappeared. Many methods for extracting the ERP components from the EEG signals have been presented as matrices. However, due to the twodimensional information (time and space) available, resource extraction is... 

    Robot control using an inexpensive P300 based BCI

    , Article 26th National and 4th International Iranian Conference on Biomedical Engineering, ICBME 2019, 27 November 2019 through 28 November 2019 ; 2019 , Pages 204-207 ; 9781728156637 (ISBN) Bahman, S ; Shamsollahi, M. B ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Brain Computer Interfaces (BCI) are an important concept of biomedical engineering because of their ability to improve life conditions for people with different disabilities. Lots of studies have worked on important characteristics of BCI systems, such as speed and accuracy, whereas price is an important aspect too. Thus, a low cost BCI system with high accuracy clearly can help more people. Our purpose in this study is to design a P300 based BCI system using a low-priced EEG headset which has an acceptable accuracy. Our final design got a mean real-time accuracy of 93.3% which is comparable to systems with much more expensive hardware. © 2019 IEEE  

    Bio-inspired nanostructured sensor for the detection of ultralow concentrations of explosives [electronic resource]

    , Article Journal of Angewandte Chemie International Edition ; 29 May 2012, Volume 51, Issue 22, P.5334-5338 Dourandish, M. (Mahdi) ; Simchi, A. (Abdolreza) ; Tamjid Shabestary, Elnaz ; Hartwig, Thomas ; Sharif University of Technology
    Abstract
    TNT: Silicon microcantilevers modified with a three-dimensional layer of vertical titanium dioxide nanotubes can be used in micromechanical sensors with optical signal detection to detect low levels of explosives such as 2,4,6-trinitrotoluene (TNT) in the gas phase, even in the presence of other volatile impurities such as n-heptane and ethanol  

    Surface Modification of Bacterial Cellulose-Reinforced Keratin Nanofibers using Pluronic/Gum Tragacanth Hydrogel Nanoparticles Produced by Concurrent gel Electrospray/Polymer Electrospinning Method

    , M.Sc. Thesis Sharif University of Technology Azarniya, Amir (Author) ; Simchi, Abdolreza (Supervisor) ; Tamjid, Elnaz (Supervisor)
    Abstract
    In this work, wool keratin/polyethylene oxide (PEO) nanofibrous scaffolds were fabricated by electrospinning method. Bacterial cellulose nanofibrils (BCNFs) were embedded in the electrospun keratin/PEO nanofibers. Incorporation of BCNFs into the nanofibers enhances their hydrophilicity, mechanical properties and cell viability, adhesion and proliferation. Water contact angle of the nanofibers decreased from 126˚ to 83˚by addition of 1 wt % BCNFs. A thermogelling hydrogel based on carboxylated pluronic (Pl-COOH) and gum tragacanth (GT) was fabricated and polymer conjugation was confirmed by FTIR and H-NMR spectroscopy. Morphological and viscoelastic properties of GT-grafted Pl-COOH hydrogels... 

    Perfect dominating sets in the cartesian products of prime cycles

    , Article Electronic Journal of Combinatorics ; Volume 14, Issue 1 N , 2007 , Pages 1-7 ; 10778926 (ISSN) Hatami, H ; Hatami, P ; Sharif University of Technology
    Australian National University  2007
    Abstract
    We study the structure of a minimum dominating set of C2n+1 n, the Cartesian product of n copies of the cycle of size 2n + 1, where 2n + 1 is a prime  

    Experimental determination of natural convection heat transfer coefficient in a vertical flat-plate solar air heater

    , Article Solar Energy ; Volume 82, Issue 10 , 2008 , Pages 903-910 ; 0038092X (ISSN) Hatami, N ; Bahadorinejad, M ; Sharif University of Technology
    2008
    Abstract
    In this study, natural convection heat transfer in a vertical flat-plate solar air heater of 2.5 m height and 1 m width, with one- and two-glass covers was studied experimentally. Totally six cases of airflow (two for air heater with one glass cover and four for air heater with two-glass covers) were considered. These cases included states that air could flow within spaces between absorber plate and glass covers or air was enclosed in such spaces. Absorber plate temperature, back-plate temperature, glass cover temperatures, mass flow rates of air within channels and the solar radiation were measured. The following relations are suggested:. For channels in which air could flow:Nu = 0.7362... 

    On the computational complexity of defining sets

    , Article Discrete Applied Mathematics ; Volume 149, Issue 1-3 , 2005 , Pages 101-110 ; 0166218X (ISSN) Hatami, H ; Maserrat, H ; Sharif University of Technology
    2005
    Abstract
    Suppose we have a family F of sets. For every S∈F, a set D⊆S is a defining set for (F,S) if S is the only element of F that contains D as a subset. This concept has been studied in numerous cases, such as vertex colorings, perfect matchings, dominating sets, block designs, geodetics, orientations, and Latin squares. In this paper, first, we propose the concept of a defining set of a logical formula, and we prove that the computational complexity of such a problem is Σ2-complete. We also show that the computational complexity of the following problem about the defining set of vertex colorings of graphs is Σ2-complete: INSTANCE: A graph G with a vertex coloring c and an integer k.QUESTION: If... 

    On the complexity of the circular chromatic number

    , Article Journal of Graph Theory ; Volume 47, Issue 3 , 2004 , Pages 226-230 ; 03649024 (ISSN) Hatami, H ; Tusserkani, R ; Sharif University of Technology
    Wiley-Liss Inc  2004
    Abstract
    Circular chromatic number, χc is a natural generalization of chromatic number. It is known that it is NP-hard to determine whether or not an arbitrary graph G satisfies χ(G)= χc(G). In this paper we prove that this problem is NP-hard even if the chromatic number of the graph is known. This answers a question of Xuding Zhu. Also we prove that for all positive integers k ≥ 2 and n ≥ 3, for a given graph G with χ(G)= n, it is NP-complete to verify if χc(G)≤ n -1/k. © 2004 Wiley Periodicals, Inc  

    , M.Sc. Thesis Sharif University of Technology Hatami, Mojgan (Author) ; Bagherzadeh, Mojtaba (Supervisor)
    Abstract
    Inert gold become catalytically active when dispersed in the form of nanoparticles. Isolated gold nanoparticles have demonstrated high catalytic activity for both oxidation and reduction reactions. In order to obtain high catalytic activity, gold nanoparticles are generally dispersed on support materials, among which oxides are commonly used. However, a substantial decrease in activity and selectivity of the immobilized catalysts is frequently observed due to the heterogeneous nature of these support materials in reaction media. In the course of our study on the metal-based catalysis for synthesis of organic compounds, we herein report that rod-shaped Au nanoparticles in aqua solution... 

    Secure Communication via Cooperation and Cooperative Jamming

    , M.Sc. Thesis Sharif University of Technology Hatami, Mohammad (Author) ; Behroozi, Hamid (Supervisor)
    Abstract
    The broadcast nature of wireless communications makes the propagation medium vulnerable to security attacks such as eavesdropping and jamming from adversarial or unauthorized users. Applying physical layer secrecy approaches will enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without using any secret keys. However, physical layer security approaches are typically feasible only when the source-eavesdropper channel is weaker than the source-destination channel. Cooperative jamming can be used to overcome this challenge and increase the secrecy rate. In this thesis, the security of two-phase relaying system with multiple... 

    Generation and Optimization of High-order Harmonics in the Interaction of Laser with N2O Molecule

    , M.Sc. Thesis Sharif University of Technology Monfared, Mohammad (Author) ; Sadighi-Bonabi, Rasoul (Supervisor) ; Irani, Elnaz (Co-Supervisor)
    Abstract
    The X-ray attosecond pulses have many useful applications for studying atomic and sub-atomic scales phenomena in attosecond scale duration. Generation and optimization of high-order harmonics is an efficient way to produce such attosecond pulses which are studied in this thesis. There are several limitations in the attosecond pulse generation such as low efficiency of high-order harmonics, long duration of output pulses and the impossibility of producing an attosecond pulse with any desired wavelength in the x-ray region. Therefore, more investigations into high harmonic generation and fully control and optimization of this process is significant. In this thesis, high harmonic generation... 

    A streaming algorithm for 2-center with outliers in high dimensions

    , Article Computational Geometry: Theory and Applications ; Volume 60 , 2017 , Pages 26-36 ; 09257721 (ISSN) Hatami, B ; Zarrabi Zadeh, H ; Sharif University of Technology
    2017
    Abstract
    We study the 2-center problem with outliers in high-dimensional data streams. Given a stream of points in arbitrary d dimensions, the goal is to find two congruent balls of minimum radius covering all but at most z points. We present a (1.8+ε)-approximation streaming algorithm, improving over the previous (4+ε)-approximation algorithm available for the problem. The space complexity and update time of our algorithm are poly(d,z,1/ε), independent of the size of the stream. © 2016 Elsevier B.V  

    A lower bound for the length of a partial transversal in a Latin square

    , Article Journal of Combinatorial Theory. Series A ; Volume 115, Issue 7 , 2008 , Pages 1103-1113 ; 00973165 (ISSN) Hatami, P ; Shor, P. W ; Sharif University of Technology
    2008
    Abstract
    It is proved that every n × n Latin square has a partial transversal of length at least n - O (log2 n). The previous papers proving these results (including one by the second author) not only contained an error, but were sloppily written and quite difficult to understand. We have corrected the error and improved the clarity. © 2008  

    Sensitive Detection and Quantification of Nitrite Ions by Metal-organic Frameworks/Gold Nanocomposites

    , M.Sc. Thesis Sharif University of Technology Mahdavi, Hossein (Author) ; Simchi, Abdoolreza (Supervisor) ; Tamjid Shabestari, Elnaz (Supervisor)
    Abstract
    Nitrite (〖NO〗_2^-) anions are ubiquitous within the physiological, industrial, environmental, and food industries. The potential toxicity risk of these inorganic compounds has well been recognized; thus, the precise detection of these ions by developing reliable and high-throughput analytical methods is crucial for health and environment security. In this study, we present a reagentless electrochemical biosensor using cobalt-based metal-organic frameworks (ZIF-67) and gold nanoparticles (Au NPs) for determination of nitrite ions. The developed biosensor provides the advantages of MOF properties including high surface area, hierarchical porosity, and tunable functionalities along with high... 

    Fabrication of 3D Graphene/Gold Porous Electrode for Biosensing Applications

    , M.Sc. Thesis Sharif University of Technology Rahmati, Reza (Author) ; Simchi, AbdolReza (Supervisor) ; Tamjid Shabestari, Elnaz (Supervisor)
    Abstract
    Today, the use of carbon nanostructures hybridized with noble metals has attracted considerable attention for the fabrication of bio-electrochemical sensors. Since the specific surface area has an immense effect on the sensing response, three-dimensional structures of graphene have a great capability to utilize in these sensors. In this research, three-dimensional graphene was provided on the porous nickel foam by chemical vapor deposition technique. By evaluation of raman spectroscopy, the time period of 20 minutes for solving of the carbon atoms into the nickel foam was selected as the main parameter of optimized conditions for the synthesis of graphene. Afterward, production of few-layer... 

    A Deep Learning Approach to Classify Motor Imagery Based on The Combination of Discrete Wavelet Transform and Convolutional Neural Network for Brain Computer Interface System

    , M.Sc. Thesis Sharif University of Technology Elnaz Azizi (Author) ; Selk Ghafari, Ali (Supervisor) ; Zabihollah, Abolghssem (Supervisor)
    Abstract
    A Brain-Computer Interface (BCI) is a communication system that does not need any peripheral muscular activity. The huge goal of BCI is to translate brain activity into a command for a computer. One of the most important topics in the brain-computer interface is motor imagery (MI), which shows the reconstruction of subjects. The electrical activities of the brain are measured as electroencephalogram (EEG). EEG signals behave as low to noise ratio also show the dynamic behaviors.In the present work, a novel approach has been employed which is based on feature extraction with discretion wavelet transform (DWT), support vector machine (SVM), Artificial Neural Network (ANN) and Convolutional... 

    Synthesis and thermogravimetric analysis of inclusion complexes of O2N2-donor Aza-crown macrocyclic ligands with [60]fullerene

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 118, Issue 3 , 2014 , pp 1631-1637 ; ISSN: 13886150 Ghanbari, B ; Gholamnezhad, P ; Hatami, M ; Sharif University of Technology
    2014
    Abstract
    A simple method for the formation of inclusion complex of [60]fullerene with two O2N2-donor aza-crown macrocyclic ligands was introduced. The products were characterized using UV-vis and IR spectroscopies as well as HPLC, and ESI mass spectrometry. The ESI mass and elemental analysis data revealed that the ratio of macroring:[60]fullerene were not the same. The binding capability of the macrorings as well as the number of the macroring addends to [60]fullerene were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Considering percentage mass loss in different steps of TG and the enthalpy changes in DSC found for each of these products, the number... 

    Design of a fault tolerated intelligent cntrol system for a nuclear reactor power control: Using extended Kalman filter

    , Article Journal of Process Control ; Vol. 24, issue. 7 , 2014 , pp. 1076-1084 ; ISSN: 09591524 Hatami, E ; Salarieh, H ; Vosoughi, N ; Sharif University of Technology
    2014
    Abstract
    In this paper an approach based on system identification is used for fault detection in a nuclear reactor. A continuous-time Extended Kalman Filter (EKF) is presented, which allows the parameters of the nonlinear system to be estimated. Also a fault tolerant control system is designed for the nuclear reactor during power changes operation. The proposed controller is an adaptive critic-based neuro-fuzzy controller. Performance of the controller in terms of transient response and robustness against failures is very good and considerable