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Nanocomposite of functionalized halloysite and Ag(0) decorated magnetic carbon dots as a reusable catalyst for reduction of dyes in water
, Article Journal of Physics and Chemistry of Solids ; Volume 152 , 2021 ; 00223697 (ISSN) ; Kazemeini, M ; Sadjadi, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
A new magnetic, catalytic nanocomposite of Hal-MT-Cys-Ag/MNCD was fabricated and utilized for catalyzing reductive de-colorization of methyl orange and rhodamin B in aqueous media at room temperature. To prepare this material, Cl-functionalized halloysite nanoclay was successively reacted with melamine and 2,4,6-trichloro-1,3,5-triazine to furnish multi-nitrogen containing ligand on halloysite surface. Then, magnetic carbon dots were crafted through a facile method and decorated with Ag nanoparticles and cysteine to furnish Cys-Ag/MNCD species. The final nanocomposite was obtained via incorporation of this latter species onto functionalized halloysite. This new composite was characterized...
Effect of the pyrrolic nitrogen functional group in the selective adsorption of CO2: GCMC, MD, and DFT studies
, Article Energy and Fuels ; Volume 35, Issue 19 , 2021 , Pages 15918-15934 ; 08870624 (ISSN) ; Mirzaee Valadi, F.M ; Latifi Pour, M ; Rashtchian, D ; Gholami, M. R ; Sharif University of Technology
American Chemical Society
2021
Abstract
In this paper, the pyrrolic nitrogen functional group's presence is investigated in the selective adsorption of CO2. The grand canonical Monte Carlo (GCMC), molecular dynamics (MD), and density functional theory (DFT) were used for this study's goal. GCMC was used to calculate adsorption isotherms, selectivity, and isosteric heats. MD was used to calculate the radial distribution function (RDF) and diffusion. Reactivity parameters, electrostatic potential (ESP), reduced density gradient (RDG), and independent gradient model (IGM) were calculated using DFT. Adsorption isotherms, selectivity, and isosteric heats demonstrated that the NH group caused the selective adsorption of CO2 among CH4,...
Modeling the R-curve effects in laminate composites using the interface thick level set method
, Article Theoretical and Applied Fracture Mechanics ; Volume 108 , August , 2020 ; Kouchakzadeh, M. A ; Sharif University of Technology
Elsevier B. V
2020
Abstract
This paper presents a new model for simulating delamination growth in composites in presence of the resistance curve (R-curve) effects. This model is extended from the interface thick level set (ITLS) method which is developed recently. In this approach the common definition of damage in the constitutive relationship of the interface elements is replaced with a new damage definition based on the thick level set (TLS) method. This new damage definition provides a direct link between fracture and damage mechanics that allows use of interface elements without a predefined cohesive law. In this paper the ITLS method is adopted to incorporate the R-curve effects caused by extended bridging, in...
A model for traffic prediction in wireless ad-hoc networks
, Article Communications in Computer and Information Science ; Volume 241 CCIS , 2011 , Pages 328-335 ; 18650929 (ISSN) ; 9783642273360 (ISBN) ; Manzuri, M. T ; Latifi, N ; Sharif University of Technology
2011
Abstract
In recent years, Wireless Ad-hoc networks have been considered as one of the most important technologies. The application domains of Wireless Ad-hoc Networks gain more and more importance in many areas. One of them is controlling and management the packet traffic. In this paper our goal is controlling the performance of every sections of pipeline of the factory by checking network periodically. Along the factory the traffic is modeled with a Poisson process. We present, with obtaining traffic packets at time (t) for each node in Wireless Ad-hoc Network, we can completely train a Neural Network and successfully predict the traffic at time (t+1) for each node. By this way we can recognize the...
Origin of the correlation of the rate constant of substrate hydroxylation by nonheme iron(IV)-oxo complexes with the bond-dissociation energy of the C-H bond of the substrate
, Article Chemistry - A European Journal ; Volume 15, Issue 27 , 2009 , Pages 6651-6662 ; 09476539 (ISSN) ; Bagherzadeh, M ; De Visser, S ; Sharif University of Technology
Wiley-VCH Verlag
2009
Abstract
Mononuclear nonheme iron containing systems are versatile and vital oxidants of substrate hydroxylation reactions in many biosystems, whereby the rate constant of hydroxylation correlates with the strength of the C-H bond that is broken in the process. The thermodynamic reason behind these correlations, however, has never been established. In this work results of a series of density functional theory calculations of substrate hydroxylation by a mononuclear nonheme iron(IV)-oxo oxidant with a 2 His/ 1Asp structural motif analogous to aketoglutarate dependent dioxygenases are presented. The calculations show that these oxidants are very efficient and able to hydroxylate strong C-H bonds,...
Collaborative privacy management in P2P online social networks
, Article 12th International ISC Conference on Information Security and Cryptology, 8 September 2015 through 10 September 2015 ; 2015 , Pages 64-72 ; 9781467376099 (ISBN) ; Alizadeh, M ; Abbas Pour, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Online Social Networks (OSNs) have become widely popular in recent years. In spite of users' interest to join OSNs, sharing vast amounts of personal information and resources in these networks might result in privacy issues for them. In the centralized OSNs, access control policies defined by users are enforced by OSN providers. Moreover, as these shared resources are stored by providers, they can access them. To avoid such problems, various architectures for decentralized OSNs are proposed. But the proposed architectures for P2P OSNs yet do not support any mechanism for collaborative privacy management on the shared content. By increasing the amount of resources such as photos which is...
Evaluating the effect of non-poisson traffic patterns on power consumption of sleep mode in the IEEE 802.16e MAC
, Article 4th IEEE and IFIP International Conference on Wireless and Optical Communications Networks, WOCN 2007, Singapore, 2 July 2007 through 4 July 2007 ; 2007 ; 1424410045 (ISBN); 9781424410040 (ISBN) ; Nayebi, M. M ; Sharif University of Technology
2007
Abstract
In this paper, we study the effect of non-Poisson traffic patterns on energy consumption for IEEE 802.16e nodes while operating in the sleep mode. In the sleep mode, a Mobile Subscribe Station (MSS) sleeps for a sleep interval and wakes up at the end of this interval in order to check buffered packet(s) at Base Station (BS) destined to it. If there is no packet, the MSS increases the sleep window up to the maximum value and sleeps again. For a more general traffic pattern (rather than Poisson), we evaluate the average power consumption. Based on our analysis, we conclude that traffic pattern plays an important role in power consumption. ©2007 IEEE
The Effect of a Critical Reflective Course on the Construction of Iranian EFL Learners’ Identity: A Case of an Online EFL Class
, M.Sc. Thesis Sharif University of Technology ; Rezaei, Saeed (Supervisor)
Abstract
The present study examines the effects of participation in a critical reflective online course upon the participants’ identity. The study drew upon both qualitative and quantitative research methodologies. The 38 participants of the study who were first degree students at Sharif University of Technology participated in ten online sessions in which ten prompts concerning intercultural issues were introduced. The data collected in the online course underwent inductive qualitative content analysis which resulted in the extraction of five themes. Following this, 18 participants were interviewed to throw more light on these findings. Qualitative and Quantitative content analyses of the data...
Dynamic Modelling of Multiple Quadrotor Suspended Load Transporting System with Variable Center of Mass via Flexible Cables
, M.Sc. Thesis Sharif University of Technology ; Saghafi, Fariborz (Supervisor)
Abstract
Using unmanned aerial vehicles in aerial payload carrying leads many changes requiring significant study and research. In recent years, there has been considerable maturation in Micro Aerial Vehicles (MAV) developement especially quadcopters. In addition to the endurance restriction, considerations on volume and weight that can be carried, and safety issues are also obstacles to the development of unmanned aerial payload carrying in urban environments. One of the ways to make a quadcopter more agile while carrying a load is to hang the cargo from the quadcopter via a cable. In this way, it is possible that quadcopters carry the cargo in a cooperative way, which if properly arranged,...
CNNdroid: GPU-accelerated execution of trained deep convolutional neural networks on android
, Article 24th ACM Multimedia Conference, MM 2016, 15 October 2016 through 19 October 2016 ; 2016 , Pages 1201-1205 ; 9781450336031 (ISBN) ; Golestani, H ; Hashemi, M ; Ghiasi, S ; Sharif University of Technology
Association for Computing Machinery, Inc
2016
Abstract
Many mobile applications running on smartphones and wear- able devices would potentially benefit from the accuracy and scalability of deep CNN-based machine learning algorithms. However, performance and energy consumption limitations make the execution of such computationally intensive algorithms on mobile devices prohibitive. We present a GPU- accelerated library, dubbed CNNdroid [1], for execution of trained deep CNNs on Android-based mobile devices. Empirical evaluations show that CNNdroid achieves up to 60X speedup and 130X energy saving on current mobile devices. The CNNdroid open source library is available for download at https://github.com/ENCP/CNNdroid
Finite element model of SWCNT under hydrostatic pressure
, Article AIP Conference Proceedings, 10 April 2007 through 12 April 2007, Sharjah ; Volume 929 , 2007 , Pages 82-88 ; 0094243X (ISSN) ; 0735404399 (ISBN); 9780735404397 (ISBN) ; Ahmadian, M. T ; Sharif University of Technology
2007
Abstract
A finite element technique is used to mimic radial deformation of single-walled carbon nanotubes under hydrostatic pressure. The elastic deformation of nanotubes is modeled via elastic beams. Properties of the beam element are evaluated by considering characteristics of the covalent bonds between the carbon atoms in a hexagonal lattice. Applying the beam model in a three dimensional space, the elastic properties of the nanotube in the transverse direction are evaluated. The effects of diameter and wall thickness on the radial and circumferential elastic moduli of zigzag and armchair nanotubes are considered. Results are in good agreement with molecular structural mechanics data in the...
Synthesis, Structure and Catalytic Application of Mn, Fe and Mo Complexes with Schiff base Ligands in the Oxidation of Olefins and Sulfides and Theoretical Mechanistic Studies on the Catalytic Activity of non-Heme Iron and Copper Enzymes
, Ph.D. Dissertation Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)Density functional theory studies of oxygen and carbonate binding to a dicopper patellamide complex
, Article Journal of Inorganic Biochemistry ; Volume 102, Issue 12 , 2008 , Pages 2171-2178 ; 01620134 (ISSN) ; Bagherzadeh, M ; Milne, B. F ; Jaspars, M ; de Visser, S. P ; Sharif University of Technology
2008
Abstract
In this work we present results of density functional theory (DFT) calculations on dicopper patellamides and their affinity for molecular oxygen and carbonate. Patellamides are cyclic octapeptides that are produced by a cyanobacterium, and may show promise as therapeutics. Thus, carbonate binding to a dicopper patellamide center gives a stable cyclic octapeptide with a twist of almost 90°. The system exists in close-lying open-shell singlet and triplet spin states with two unpaired electrons in orthogonal σ* orbitals on each metal center. Subsequently, we replaced carbonate with dioxygen and found a stable Cu2(μ-O)2 diamond shaped patellamide core. In this structure the original dioxygen...
Complexity and variability of the center of pressure time series during quiet standing in patients with knee osteoarthritis
, Article Clinical Biomechanics ; Volume 32 , 2016 , Pages 280-285 ; 02680033 (ISSN) ; Sanjari, M. A ; Karimi, M ; Parnian Pour, M ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Background While several studies have investigated the traditional linear measures in patients with knee osteoarthritis, no study has yet reported the non-linear structure of postural sway in these patients. Methods We used two non-linear methods, recurrence quantification analysis (percent of determinism-%DET) and central tendency measure, to respectively investigate differences in the complexity and variability of sway dynamics between two groups of knee osteoarthritis patients (n = 27) and healthy controls (n = 27) under different conditions of postural and cognitive tasks. The experimental conditions included standing on (1) rigid surface with open eyes; (2) rigid surface with closed...
Evaluation of demand side behaviors in cost-emission based PM scheduling under restructured environment
, Article 24th Iranian Conference on Electrical Engineering, ICEE 2016, 10 May 2016 through 12 May 2016 ; 2016 , Pages 885-890 ; 9781467387897 (ISBN) ; Rashidinejad, E ; Rashidinejad, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Security constrained Preventive Maintenance (PM) scheduling is addressed as a crucial issue especially coping with new challenges of smart grids. Under the smart grid environment, Demand Response Resources (DRRs) are considered as virtual power plants in energy policy decisions which affect the controllability of power system ranging from short-term to long-term. Here, DRRs are regarded as a virtual resource of capacity reserve acquisition. Furthermore, under new environment, multifarious objectives will be imposed to PM scheduling which can be replicated into a single objective problem via a weighted approach with consideration of arbitrary weighting coefficients. In this paper, a new...
Geometric optimization of a double pipe heat exchanger with combined vortex generator and twisted tape: A CFD and response surface methodology (RSM) study
, Article Thermal Science and Engineering Progress ; Volume 18 , 2020 ; Amiri, P ; Saffari Pour, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this research, a numerical investigation is done on the effect of employing the new combined vortex generators, the twisted tape turbulator and Al2O3-H2O nanofluid as the involved base fluid. Such study is carried out on the behavior of the heat transfer rate and the pressure drop of a double pipe heat exchanger. Accordingly, the response surface methodology (RSM) grounded on the central composite design (CCD) is used for acquiring the optimized geometry of the combined vortex generator and twisted tape turbulator. In order to have the maximum Nusselt number and minimum friction factor, twenty cases with different pitches ratio Pil=0.09-0.18, angles (θ=0-30°) and Reynolds numbers (Re =...
A Product Portfolio Scenario Selection Model Considering Multi Products Focusing on Business Sustainability
, M.Sc. Thesis Sharif University of Technology ; Fatahi Valilai, Omid (Supervisor)
Abstract
In each organization, decision-making about products and their impact on the profitability of the organization is vital. Today, with the constant changes and resource constraints, as well as the growing importance of environmental issues for organizations, creating a decision model that considers all of the aformentioned aspects is vital. This study considers ten effective factors related to product portfolio and focuses on maintaining business sustainability in multi-product organizations. First, by assessing the relationship between criteria and products, the priority and weight of each of the criteria by the network analysis process (ANP) method are determined. In the next step, using the...
Efficient oxidation of olefins and sulfides catalyzed by manganese(III)-tridentate Schiff base complex using UHP as oxidant
, Article Catalysis Communications ; Volume 9, Issue 7 , 2008 , Pages 1600-1606 ; 15667367 (ISSN) ; Tahsini, L ; Latifi, R ; Sharif University of Technology
2008
Abstract
Catalytic studies were performed to develop a simple oxidation system for olefins and sulfides using manganese(III)-tridentate Schiff base complex, Mn(N-OPh-sal)(acac)(EtOH) (N-HOPh-Hsal = N-hydroxyphenyl-salicyldienamine, Hacac = acetylacetone), and urea-hydrogen peroxide (UHP) as terminal oxidant. Conversions up to 90% for olefins at 0 °C and 96% for sulfides at room temperature as well as sulfoxide selectivity up to 73% were achieved in short reaction times. Also this study confirms the accelerating effect of strong π-donor axial ligands such as imidazole (ImH) on the oxidation reactions. © 2008 Elsevier B.V. All rights reserved
Second Harmonic Generation (SHG) measurement affected by electric field
, Article Scientia Iranica ; Volume 14, Issue 3 , 2007 , Pages 236-239 ; 10263098 (ISSN) ; Rajai, P ; Latifi, H ; Sharif University of Technology
Sharif University of Technology
2007
Abstract
A type II (eoe: extraordinary-ordinary-extraordinary) phase matching condition in a 2nd Harmonic Generation of Nd-YAG laser under a high electric field in a uniaxial KDP crystal has been measured. Type II phase matching takes place when the two mixing waves are of orthogonal polarizations (extraordinary-ordinary) and the 2nd harmonic radiation corresponds to an extraordinary wave. By applying an electric field along the X(Y) axes of the crystal, a new phase-matching angle was measured under the influence of different electric fields. The deflection angle of the SHG beam was measured as a function of the applied voltage. An optical collector will focus the 1st harmonic and a fraction of its...
Modelling of Turbulence and Chemistry Interaction Using an Optimized Conditional Source-term Estimation Approach
, M.Sc. Thesis Sharif University of Technology ; Salehi, Mohammad Mahdi (Supervisor)
Abstract
The purpose of this study is to evaluate the performance of the optimized conditional source-term estimation approach. This model was first implemented in a computational fluid dynamics code, and then the Bernstein expansion was used to optimize it. For validation, two pre-mixed turbulent flames with different turbulence intensity and equivalence ratios were modeled with the optimized and RANS model. The results were obtained for mass fraction of the main and intermediate species, velocity and temperature examined in different sections. In the first flame, the turbulence intensity is low, and the flame is in the flamelet regimes; As a result, the results obtained with the optimized model are...