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A Study on Deformation Behavior During Asymmetrical Rolling of Low Carbon Steels and Subsequent Microstructural Phenomena
, M.Sc. Thesis Sharif University of Technology ; Serajzadeh, Siamak (Supervisor)
Abstract
In this study, static recrystallization (Rex) of a low carbon steel after cold rolling has bees simulated under non-isothermal condition by employing cellular automata (CA) method. Symmetric cold rolling and asymmetric cold rolling (ASR) which was arisen by inequality of friction coefficient have been applied as primary cold deformation. Residual stress and strain field after deformation, and temperature rate and distribution of specimens during annealing has been evaluated by employing two different models based on finite element method. Initial microstructure has been developed by haphazardly distribution of grains and topological adjustments were imposed on it. Results of FEM models were...
Immobilized Manganese-porphyrin and Molybdenum-Schiff Base Complexes on Functionalized Magnetic Nanoparticles as Efficient Recyclable Nanocatalysts in Hydrocarbon and Sulfide Oxidation Reactions
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this thesis, functionalized Fe3O4 nanoparticles have been utilized as a support for immobilization of homogeneous catalysts. The catalytic activity of the supported heterogeneous nanocatalysts was investigated in hydrocarbon and sulfide oxidation reactions. In the first part of this research, imidazole functionalized Fe3O4 nanoparticles (Fe3O4@SiO2-Im) were used as a support to anchor manganese porphyrin complex, [MnT(4-OMeP)P]OAc; via axial ligation. Catalytic application of the immobilized manganese porphyrin was studied in oxidation of alkenes and sulfides. To find suitable reaction conditions, the effect of different parameters such as solvent and temperature on immobilization process...
Audio-visual speech recognition techniques in augmented reality environments
, Article Visual Computer ; Vol. 30, issue. 3 , March , 2014 , pp. 245-257 ; ISSN: 01782789 ; Ghorshi, S ; Mortazavi, M ; Sharif University of Technology
2014
Abstract
Many recent studies show that Augmented Reality (AR) and Automatic Speech Recognition (ASR) technologies can be used to help people with disabilities. Many of these studies have been performed only in their specialized field. Audio-Visual Speech Recognition (AVSR) is one of the advances in ASR technology that combines audio, video, and facial expressions to capture a narrator's voice. In this paper, we combine AR and AVSR technologies to make a new system to help deaf and hard-of-hearing people. Our proposed system can take a narrator's speech instantly and convert it into a readable text and show the text directly on an AR display. Therefore, in this system, deaf people can read the...
Using augmented reality and automatic speech recognition techniques to help deaf and hard of hearing people
, Article ACM International Conference Proceeding Series ; 2012 ; 9781450312431 (ISBN) ; Ghorshi, S ; Mortazavi, M ; Sharif University of Technology
2012
Abstract
Recently, many researches show Augmented Reality (AR) and Automatic Speech Recognition (ASR) can help people with disabilities. In this paper we implement an innovative system for helping deaf people by combining AR, ASR, and AVSR technologies. This system can instantly take narrator's speech and converts it into readable text and shows it directly on AR display. We show that our system's accuracy becomes over 85 percent on average, by using different ASR engines near using an AVSR engine in different noisy environments. We also show in a survey that more than 90 percent of deaf people on average need such system as assistant in portable devices, near using only text or only sign-language...
Combining augmented reality and speech technologies to help deaf and hard of hearing people
, Article Proceedings - 2012 14th Symposium on Virtual and Augmented Reality, SVR 2012 ; 2012 , Pages 174-181 ; 9780769547251 (ISBN) ; Ghorshi, S ; Mortazavi, M ; Sharif University of Technology
2012
Abstract
Augmented Reality (AR), Automatic Speech Recognition (ASR) and Text-to-Speech Synthesis (TTS) can be used to help people with disabilities. In this paper, we combine these technologies to make a new system for helping deaf people. This system can take the narrator's speech and convert it into a readable text and show it directly on AR display. To improve the accuracy of the system, we use Audio-Visual Speech Recognition (AVSR) as a backup for the ASR engine in noisy environments. In addition, we use the TTS system to make our system more usable for deaf people. The results of testing the system show that its accuracy is over 85 percent on average in different places. Also, the result of a...
Analyzing area penalty of 32-bit fault tolerant ALU using BCH code
, Article Proceedings - 2011 14th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2011, 31 August 2011 through 2 September 2011, Oulu ; 2011 , Pages 409-413 ; 9780769544946 (ISBN) ; Vahdat, B. V ; Mortazavi, M ; Sharif University of Technology
2011
Abstract
In this paper we have presented a hardware implementation of 32-bit Fault-tolerant ALU (Arithmetic and Logic Unit) which is compared with the current techniques, Residue code, Triple Modular Redundancy (TMR) with single voting and TMR with triplicated voter that are widely used in space application to mitigate the upsets, in terms of area penalty. We consider BCH (Bose, Chaudhuri, and Hocquenghem) codec (encoder, decoder) using the prototyping FPGA (Field Programmable Gate Array). The new implementation of ALU employing BCH code on Spartan-3 FPGA has been provided. The results show that our fault tolerant method has the lowest hardware overhead and it can correct any 5-bit error in any...
FMNV continuous non-malleable encoding scheme is more efficient than believed
, Article 13th International ISC Conference on Information Security and Cryptology, 7 September 2016 through 8 September 2016 ; 2016 , Pages 72-78 ; 9781509039494 (ISBN) ; Salmasizadeh, M ; Daneshgar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Non-malleable codes are kind of encoding schemes which are resilient to tampering attacks. The main idea behind the non-malleable coding is that the adversary can't be able to obtain any valuable information about the message. Non-malleable codes are used in tamper resilient cryptography and protecting memory against tampering attacks. Several kinds of definitions for the non-malleability exist in the literature. The Continuous non-malleability is aiming to protect messages against the adversary who issues polynomially many tampering queries. The first continuous non-malleable encoding scheme has been proposed by Faust et al. (FMNV) in 2014. In this paper, we propose a new method for proving...
Synthesis, characterization and catalytic activity of supported vanadium Schiff base complex as a magnetically recoverable nanocatalyst in epoxidation of alkenes and oxidation of sulfides
, Article Journal of Organometallic Chemistry ; Volume 897 , 2019 , Pages 200-206 ; 0022328X (ISSN) ; Bahjati, M ; Mortazavi Manesh, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
A new magnetically separable nanocatalyst was successfully synthesized by immobilizing of vanadyl acetylacetonate complex, [VO(acac)2], onto silica coated magnetite nanoparticles previously functionalized with 3-aminopropyltriethoxysilane (3-APTES) and reacted by 5-bromosalicylaldehyde to form Schiff base moiety. The obtained nanocatalyst was characterized by elemental analysis (CHN), FT-IR spectroscopy, Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and thermogravimetric analysis (TGA). Eventually, the resulting nanoparticles were used as catalyst for epoxidation of alkenes and...
Manganese(III) porphyrin anchored onto magnetic nanoparticles via “Click” reaction: An efficient and reusable catalyst for the heterogeneous oxidation of alkenes and sulfides
, Article Inorganic Chemistry Communications ; Volume 107 , 2019 ; 13877003 (ISSN) ; Hosseini, M ; Mortazavi Manesh, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Oxidation of a variety of organic compounds, using Mn-porphyrin, mesotetrakis(4-hydroxyphenyl)porphyrinatomanganese(III), supported onto functionalized silica-coated magnetic nanoparticles via “Click” reaction has been investigated. The heterogeneous catalyst was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP/OES) and energy-dispersive X-ray spectroscopy (EDX). Thermogravimetric analysis (TGA) demonstrated that the prepared catalyst was thermally stable to almost 300 °C, exhibiting high thermostability of the nanocatalyst over a broad range of temperatures. This...
Investigating the features of a pentagon array for studying Extensive Air Showers
, Article Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment ; Volume 962 , 2020 ; Rastegarzadeh, G ; Mortazavi Moghaddam, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
We used a method to evaluate angular accuracy for air showers direction recorded by a pentagon array of scintillation detectors. This is achieved by using the coincidences between the air showers recorded by the two sub-arrays. Also, using the CORSIKA code the angular precision of this array and the effect of inherent error on it is obtained at different energies of the primary particles and at different zenith angles. © 2020 Elsevier B.V
Enhancing water desalination in graphene-based membranes via an oscillating electric field
, Article Desalination ; Volume 495 , December , 2020 ; Moosavi, A ; Nouri Borujerdi, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Water desalination methods on the basis of newly developed graphene-based membrane have been introduced as a more efficient alternative for the conventional water purification technologies such as classical thermal desalination and reverse osmosis (RO). However, the increase of water permeation rate and ion rejection are still the main subjects in this field. In this study, a new method based on using oscillating electric field is proposed to improve the performance of nanoporous graphene. The effects of the amplitude and oscillation frequency of the electric field and the pore size of the membrane on the water permeation and salt rejection are studied by conducting molecular dynamics...
Strong continuous non-malleable encoding schemes with tamper-detection
, Article Information Sciences ; Volume 451-452 , 2018 , Pages 253-270 ; 00200255 (ISSN) ; Salmasizadeh, M ; Daneshgar, A ; Sharif University of Technology
Elsevier Inc
2018
Abstract
A non-malleable encoding scheme is a keyless encoding scheme which is resilient to tampering attacks. Such a scheme is said to be continuously secure if the scheme is resilient to attacks containing more than one tampering procedure. Moreover, such a scheme is said to have the T-tamper-detection property if any kind of tampering attack by an adversary chosen from a predetermined class of algorithms T is detected. Faust et al. have introduced a continuous non-malleable encoding scheme based on non-interactive zero-knowledge (NIZK) which is secure in a strong model for which the adversary receives the tampered codeword as a response to its tampering query if the tampered codeword is not...
Optimal energy sharing for cooperative relaying in a random access network with energy harvesting nodes
, Article IEEE Transactions on Green Communications and Networking ; Volume 5, Issue 1 , 2021 , Pages 231-242 ; 24732400 (ISSN) ; Ashtiani, F ; Mirmohseni, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
In this article, we consider an energy harvesting cooperative network comprised of two data sources and one relay. All nodes transmit based on a predefined slotted Aloha protocol in a random access environment. The main challenge we study is to find how the relay node must share its energy between two sources to optimize their QoS metrics, i.e., throughput and average transmission delay (ATD), separately. Thus, according to our multi-source scenario, we encounter a multi-objective optimization problem (MOOP). Since the relay does not prioritize between two sources, in order to solve the MOOP, we optimize equal-weight linear aggregation of the QoS metrics of two sources. Interestingly, we...
A new model in correlating the activity coefficients of aqueous electrolyte solutions with ion pair formation
, Article Fluid Phase Equilibria ; Volume 261, Issue 1-2 , December , 2007 , Pages 313-319 ; 03783812 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Sharif University of Technology
2007
Abstract
In this work, the Ion Pair Modified Ghotbi-Vera Mean Spherical Approximation (IP-MGV-MSA) model was proposed to correlate the mean ionic activity coefficients (MIAC) for a number of symmetric and asymmetric aqueous electrolyte solutions at 25 °C. The new model is based on the recently proposed MGV-MSA model by Mortazavi-Manesh et al. In the IP-MGV-MSA model, the effects arising from the ion pair formation in the electrolyte solution was taken into account. Also, in the proposed model, while the cation diameter as well as the relative permittivity of water was considered to be dependent on electrolyte concentration, the anion diameter was independent of electrolyte concentration. The results...
Modification of the GV-MSA model in obtaining the activity and osmotic coefficients of aqueous electrolyte solutions
, Article Fluid Phase Equilibria ; Volume 240, Issue 2 , 2006 , Pages 167-172 ; 03783812 (ISSN) ; Taghikhani, V ; Ghotbi, C ; Sharif University of Technology
2006
Abstract
In this work a modified form of the Ghotbi-Vera Mean Spherical Approximation model (MGV-MSA) has been used to correlate the mean ionic activity coefficients (MIAC) for a number of symmetric and asymmetric aqueous electrolyte solutions at 25 °C. In the proposed model the hard sphere as well as the electrostatic contributions to the MIAC and the osmotic coefficient of the previously GV-MSA model has been modified. The results of the proposed model for the MIAC of the electrolyte solutions studied in this work are used to directly calculate the values of the osmotic coefficients without introducing any new adjustable parameter. In the MGV-MSA model the cation diameter as well as the relative...
Water desalination by charged multilayer graphene membrane: A molecular dynamics simulation
, Article Journal of Molecular Liquids ; Volume 355 , 2022 ; 01677322 (ISSN) ; Moosavi, A ; Nouri Borujerdi, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Graphene, due to its unique excellent properties, is proposed as a developing method with high efficiency compared to classical water desalination methods. In this regard, charging the membrane is considered a promising and effective approach to enhance the performance of the graphene membrane. In this research, by using molecular dynamics simulations, the water desalination by charged multilayer graphene is evaluated and the influence of electric charge amount and geometric parameters, including the pore diameter and the interlayer distance, are investigated. According to the results, the multilayer nanoporous graphene with 16.35 Å pore diameter, in which the electric charge is distributed...
A new model for predicting activity coefficients in aqueous solutions of amino acids and peptides
, Article Journal of Chemical Thermodynamics ; Volume 35, Issue 1 , 2003 , Pages 101-112 ; 00219614 (ISSN) ; Ghotbi, C ; Taghikhani, V ; Sharif University of Technology
2003
Abstract
A new two-parameter model based on the perturbation of a hard-sphere reference has been developed to correlate the activity coefficients of several amino acids and simple peptides in aqueous solutions. The hard-sphere equation of state used as the reference in the model was proposed recently by Ghotbi and Vera. The perturbation terms coupled with the reference hard-sphere equation of state are attributed to the dispersion forces and the dipole-dipole interactions. The Lennard-Jones and Keesom potential functions are used to represent the dispersion and dipole-dipole interactions, respectively. The results of the new model are compared with those obtained by other models. It is shown that the...
Molecular dynamics investigation of β-SiC behavior under three-axial tensile loading [electronic resource]
, Article Journal of Computational and Theoretical Nanoscience ; November 2011, Volume 8, Number 11, PP. 2187-2192 ; Simchi, A. (Abdolreza) ; Besharati-Givi, M.K ; Rajabpour, A ; Sharif University of Technology
Abstract
Molecular dynamics (MD) simulations were used to study the mechanical behaviour of β-SiC at nano-scale under tensile loading. Effects of loading rate and tensile temperature on the mechanical properties and failure were studied. Modified embedded-atom method (MEAM) potential and Berendsen thermostat were utilized for modelling. Periodic boundary conditions were employed and the behaviour of material was analyzed under three-axial loading condition at which the stress–strain relation was acceptably size independent. It is shown that with increasing the loading rate from 5 m/s to 70 m/s, the failure strain increases without a remarkable change in the stress–strain relationship. The MD...
Sole versus dual-sourcing under order dependent lead-times and prices [electronic resource]
, Article Computers And Operations Research, Published in: Elsevier Journals ; Volume 36, Issue 12, December 2009, Pages 3272–3280 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, we consider a dual-sourcing model with constant demand and stochastic lead times. Two suppliers may be different in terms of purchasing prices and lead-time parameters. The ordering takes place when the inventory level depletes to a reorder level, and the order is split among two suppliers. Unlike previous works in the order splitting literature, the supply lead time between vendor and buyer as well as unit purchasing prices is considered to be order quantity dependent. The proposed model finds out the optimal reorder point, order quantity and splitting proportion, using a solution procedure. Numerical results show that neglecting the relationship between ordering batch size...
Human serum protein adsorption onto synthesis nano-hydroxyapatite
, Article Protein Journal ; Volume 31, Issue 2 , February , 2012 , Pages 150-157 ; 15723887 (ISSN) ; Massah Bidgoli, M ; Behrashi, M ; Mohsen Nia, A ; Sharif University of Technology
2012
Abstract
Adsorption of human serum proteins (Albumin and total protein) onto high purity synthesis nano-hydroxyapatite (HA), Ca 10(PO 4) 6(OH) 2, has been studied in a wide temperature range by UV-visible spectrophotometer. Adsorption isotherm is basically important to describe how solutes interact with adsorbent, andiscriticalinoptimizing the use of adsorbent. Inthe present study, the experimental results werefitted tothe Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) models to obtain the characteristic parameters of each model and square of the correlation coefficients (R 2). According to the results, the DR isotherm model had the best agreement with the experimental data. The effect of...