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Studies on the properties and structure of electron-beam crosslinked low-density polyethylene/poly[ethylene-co-(vinyl acetate)] blends
, Article Polymer International ; Volume 54, Issue 4 , 2005 , Pages 686-691 ; 09598103 (ISSN) ; Frounchi, M ; Sabet, M ; Sharif University of Technology
2005
Abstract
Blends of low-density polyethylene (LDPE) and poly[ethylene-co-(vinyl acetate)] (PEVA), crosslinked by electron-beam (EB) radiation, formed separate crystalline lattices with a homogeneous amorphous phase. The crystallinity of the EB-exposed samples slightly decreased, as verified by a slight reduction in the densities and melting heats and temperatures of the samples. The results obtained from both gel content and hot set tests showed that the degree of crosslinking in the amorphous regions was dependent on the dose and blend composition. The molecular weights between the crosslinks, measured from creep data, showed that an increasing PEVA content resulted in tighter network structures,...
Extended and Unscented Kalman filters for parameter estimation of an autonomous underwater vehicle
, Article Ocean Engineering ; Vol. 91, issue , 2014 , p. 329-339 ; Sarhadi, P ; Zarini, M ; Sharif University of Technology
2014
Abstract
In this paper, a high performance procedure for estimating of hydrodynamic coefficients in Autonomous Underwater Vehicles (AUV's) is proposed. In modeling of an AUV, experimental data should be verified and validated using appropriate techniques. Due to implementation complexity in calculating methods, computation of hydrodynamic parameters is challenging. This paper presents analytical approaches for estimating an AUV's hydrodynamic coefficients. Nonlinear Kalman Filter (KF) algorithms are implemented to estimate unknown augmented states (coefficients). A comparative study is conducted which shows the superior performance of Unscented Kalman Filter (UKF) in comparison with Extended Kalman...
A cost-effective methodology to compare travel time and speed: A tale of 11 cities
, Article Proceedings of the Institution of Civil Engineers: Municipal Engineer ; Volume 175, Issue 2 , 2022 , Pages 84-94 ; 09650903 (ISSN) ; Namdarpour, F ; Mesbah, M ; Sharif University of Technology
ICE Publishing
2022
Abstract
Urban commuters and road authorities are interested in knowing how well their city can manage traffic conditions. It is challenging to make a fair comparison among global cities due to the absence of a consistent, publicly accessible and inexpensive framework. This study proposes a methodology to compare travel time and average speed in different cities. Large cities have a central core, in which many of the major activities take place. This core is called downtown or the central business district (CBD). In this study, a comparison is made by simulating the morning commute trips from origins outside to destinations inside the CBD. The proposed framework outlines how the city and the CBD...
A cost-effective methodology to compare travel time and speed: A tale of 11 cities
, Article Proceedings of the Institution of Civil Engineers: Municipal Engineer ; 2021 ; 09650903 (ISSN) ; Namdarpour, F ; Mesbah, M ; Sharif University of Technology
ICE Publishing
2021
Abstract
Urban commuters and road authorities are interested in knowing how well their city can manage traffic conditions. It is challenging to make a fair comparison among global cities due to the absence of a consistent, publicly accessible and inexpensive framework. This study proposes a methodology to compare travel time and average speed in different cities. Large cities have a central core, in which many of the major activities take place. This core is called downtown or the central business district (CBD). In this study, a comparison is made by simulating the morning commute trips from origins outside to destinations inside the CBD. The proposed framework outlines how the city and the CBD...
Experimental investigation of effects of the feed flow rate and “tail scoop-wall” clearance on the performance of a gas centrifuge by feeding a Freon mixture
, Article Separation Science and Technology (Philadelphia) ; Volume 51, Issue 7 , 2016 , Pages 1259-1267 ; 01496395 (ISSN) ; Outokesh, M ; Karimi Sabet, J ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
ABSTRACT: Experimental study of the performance of a gas centrifuge can be appreciably simplified if instead of isotopic mixtures, a binary mixture of gases with large molecular weight difference is used. The current study undertook this approach by injecting a 53%–47% (w/w) mixture of “Freon12-Freon22” into a gas centrifuge. The two parameters, whose investigation was the objective of the current study were: the feed flow rate (F), and the clearance between tail scoop and the rotor wall (d). The results demonstrated that changing the scoop-wall clearance has the most significant effect on the cut (θ), so that by fixing “d”, “θ” becomes nearly invariant. The head separation factor (α)...
Automatic access control based on face and hand biometrics in a non-cooperative context
, Article Proceedings - 2018 IEEE Winter Conference on Applications of Computer Vision Workshops, WACVW 2018 ; Volume 2018-January , 2018 , Pages 28-36 ; 9781538651889 (ISBN) ; Bonderup, M. B ; Asadi Aghbolaghi, M ; Avots, E ; Nasrollahi, K ; Escalera, S ; Kasaei, S ; Moeslund, T. B ; Anbarjafari, G ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Automatic access control systems (ACS) based on the human biometrics or physical tokens are widely employed in public and private areas. Yet these systems, in their conventional forms, are restricted to active interaction from the users. In scenarios where users are not cooperating with the system, these systems are challenged. Failure in cooperation with the biometric systems might be intentional or because the users are incapable of handling the interaction procedure with the biometric system or simply forget to cooperate with it, due to for example, illness like dementia. This work introduces a challenging bimodal database, including face and hand information of the users when they...
Thermodynamic modeling of PVTx properties for several water/hydrocarbon systems in near-critical and supercritical conditions
, Article Korean Journal of Chemical Engineering ; Volume 30, Issue 1 , January , 2013 , Pages 201-212 ; 02561115 (ISSN) ; Mozdianfard, M. R ; Karimi Sabet, J ; Sharif University of Technology
2013
Abstract
Both the equation of state-excess Gibbs energy (EoS/GE) model and the cubic plus association (CPA) equation of state (EoS) are compared in this study with respect to their accuracy in the correlation of PVTx for systems such as water/methanol, water/ethanol, water/benzene, water/toluene, water/methane, water/n-butane, water/n-pentane, water/n-hexane, water/heptane, and water/octane, in supercritical conditions within temperature and pressure ranges of (573-698 K) and (7. 0-276. 0 MPa), respectively. In the proposed EoS/GE model, Peng-Robinson (PR) equation of state, linear combination Vidal-Michelsen (LCVM) and Wong-Sandler (WS) mixing rules in conjunction with UNIQUAC activity coefficient...
Analysis of Airborne Particulate Matter Toxicity and its Origin
, M.Sc. Thesis Sharif University of Technology ; Erhami, Mohammad (Supervisor)
Abstract
Epidemiological studies have shown a positive association between particulate matters exposure and adverse health effects. However, the insufficient knowledge about the influences of components or characteristics of these particles on their health effects and toxicity leads into inefficient control practices for reducing particulates health effects. So, relationship between particles toxicity and their emission sources and components is a valuable criterion in particle emission control strategies. Moreover, as people spend most of their time in indoor environment, investigating the main sources and components of particulate toxicity in indoor environment and finding the influence of outdoor...
Step-by-step improvement of mixed-matrix nanofiber membrane with functionalized graphene oxide for desalination via air-gap membrane distillation
, Article Separation and Purification Technology ; Volume 256 , 2021 ; 13835866 (ISSN) ; Karimi Sabet, J ; Abbasi, F ; Moosavian, M. A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
A straightforward three-stage method was applied to fabricate a super-hydrophobic mixed-matrix nanofiber membrane using the electrospinning method for desalination purpose. First, a hydrothermal technique was applied to synthesize a super-hydrophobic nano-sheet, called octadecylamine-reduced graphene oxide (ODA-rGO) with a water contact angle of 162°, which was then added to PVDF-HFP dope solution. After, 0.005 wt% LiCl was added to the dope solution to decrease the mean pore size by increasing solution conductivity. Moreover, some membranes were hot-pressed to improve liquid entry pressure (LEP). Eventually, a top-quality nanofiber membrane was synthesized using 0.1 wt% ODA-rGO and 0.005...
Traffic State Prediction via Macroscopic Fundamental Diagram in an Urban Network
, M.Sc. Thesis Sharif University of Technology ; Nassiri, Habibollah (Supervisor)
Abstract
The road authorities of a city have the responsibility of constantly assessing how well their city performs when traffic conditions are taken into account. In many metropolises around the world, if not taken preventive measures, there will be observed a density above the network capacity and a noticeable decrease in the level of service, especially in the morning and evening peak hours. Also, the dynamic congestion pricing of certain areas based on the traffic condition has always been considered significant by urban planning officials. Since this is not possible except by constantly assessing the current traffic state, a variety of methods have been used to predict the future traffic...
Synthesis of TiO2 hollow spheres using titanium tetraisopropoxide: Fabrication of high efficiency dye sensitized solar cells with photoanodes of different nanocrystalline TiO2 sub-layers
, Article RSC Advances ; Vol. 4, issue. 101 , Oct , 2014 , p. 58064-58076 ; Feshki, S ; Naeimi Sani Sabet, M ; Anajafi, Z ; Taghavinia, N ; Sharif University of Technology
2014
Abstract
In this research TiO2 hollow spheres with different diameters were prepared using titanium tetraisopropoxide (TTIP) as the TiO2 precursor. Carbon spheres with average sizes of 230, 325 and 450 nm were prepared as the templates by hydrothermal method. Then TiO2 was deposited on the surface of the carbon spheres through a liquid phase deposition (LPD) process. This two dimensional growth was performed in an appropriate concentration of TTIP and different LPD times. Finally the TiO2 hollow spheres were achieved for specific LPD times by burning the carbon templates. Two kinds of TiO2 nanocrystals with sizes around 20 nm were hydrothermally grown in acidic (pH = 1.5) and basic (pH = 10)...
Metallurgical and mechanical properties of underwater friction stir welds of Al7075 aluminum alloy
, Article Journal of Materials Processing Technology ; Volume 262 , 2018 , Pages 239-256 ; 09240136 (ISSN) ; Kokabi, A. H ; Sabet, H ; Paidar, M ; Ojo, O. O ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Travel speeds between 25–300 mm/min and tool rotational speeds of 800 and 1250 rpm were employed for this study. The microstructure, mechanical properties and fracture surfaces of the joints were studied. Underwater environment and an increase in travel speed significantly increase the precipitates’ volume fraction, reduce the average grain and precipitate sizes of the weld nugget zones. A critical travel speed of 150 mm/min is attained in underwater welds beyond which the average grain sizes remain relatively the same. Average grain and precipitate sizes have linear relationships with the tool rotational and travel speed ratio. Optimum weld strengths of 396 and 360 MPa were obtained in the...
Dynamics and Control of a Set of Wheeled Robots on a Non-planar Surfaces to Perform Specific Mission
,
M.Sc. Thesis
Sharif University of Technology
;
Sayyaadi, Hassan
(Supervisor)
Abstract
The aim of this article is ancestral control of a set of 3-wheel robots with non-holonomics dynamics for hunting and covering around moving target. Robots have mass and inertia and the wheels' mass have been considered in the dynamics of robots. The output of controller is wheel's torque and front wheel's steering torque. Moving target dynamics has been considered in a way that it is escaping from invader and the target has holonomics dynamic. To derive the equation of motion, Kane's dynamics procedure has been used. Robots are equipped to sensors for distance assessment, vision angle assessment and also signal receiver antenna. To estimate relative position and variables of other robots'...
Identification of Factors Affecting the Implementation of CRM Systems in Project Based Firms
, M.Sc. Thesis Sharif University of Technology ; Najmi, Manoochehr (Supervisor)
Abstract
Customer relationship management is a comprehensive strategy for managing the relationships with customers. Customer relationship management involves technology for automation, organizing, and adaptation of business processes, including sales activities, marketing and customer service. Main purpose of CRM is finding and attracting new customers, maintaining current customers, attracting the organization's former customers, reducing marketing costs and customer service. Most studies in this area are related to B-C organizations and few studies are related to B-B and especially project based organizations. This study aimed to identify the factors affecting the implementation of customer...
Clustering and Embedding Graphs into Trees
, M.Sc. Thesis Sharif University of Technology ; Daneshgar, Amir (Supervisor)
Abstract
In this thesis, we study the following question stating that “how well a tree structure can approximate the clustering structure of a graph”.To do this, we first focus on the DJS algorithm proposed by Daneshgar et.al. and second we consider the minimum distortion tree approximation algorithm proposed by Abraham et.al.We conclude, using some experimental results, that the minimum spanning tree algorithm extracts some geometric aspects of the data set that the Abraham et.al. algorithm can not track
Parameters Identification for Mathematical Model of The Fission Yeast Cell Cycle Using Genetic Algorithm
, M.Sc. Thesis Sharif University of Technology ; Ghaffari, Ali (Supervisor)
Abstract
Soft computing consists of a set of powerful methods that have been successfully applied to many different application domains, including business, engineering, and bioinformatics. In this research we propose an innovative approach that uses genetic algorithms to mine a set of behavior data output by a biological system in order to determine the kinetic parameters of the system. In our approach, the machine learning method is integrated with the framework of existent biological information in a wiring diagram so that its findings are expressed in a form of system dynamic behavior. An application of the method to the cell division cycle model has shown that the method can discover optimum...
Standard SPECT myocardial perfusion estimation from half-time acquisitions using deep convolutional residual neural networks
, Article Journal of Nuclear Cardiology ; 2020 ; AmirMozafari Sabet, K ; Arabi, H ; Pourkeshavarz, M ; Teimourian, B ; Ay, M. R ; Zaidi, H ; Sharif University of Technology
Springer
2020
Abstract
Introduction: The purpose of this work was to assess the feasibility of acquisition time reduction in MPI-SPECT imaging using deep leering techniques through two main approaches, namely reduction of the acquisition time per projection and reduction of the number of angular projections. Methods: SPECT imaging was performed using a fixed 90° angle dedicated dual-head cardiac SPECT camera. This study included a prospective cohort of 363 patients with various clinical indications (normal, ischemia, and infarct) referred for MPI-SPECT. For each patient, 32 projections for 20 seconds per projection were acquired using a step and shoot protocol from the right anterior oblique to the left posterior...
Standard SPECT myocardial perfusion estimation from half-time acquisitions using deep convolutional residual neural networks
, Article Journal of Nuclear Cardiology ; Volume 28, Issue 6 , 2021 , Pages 2761-2779 ; 10713581 (ISSN) ; AmirMozafari Sabet, K ; Arabi, H ; Pourkeshavarz, M ; Teimourian, B ; Ay, M. R ; Zaidi, H ; Sharif University of Technology
Springer
2021
Abstract
Introduction: The purpose of this work was to assess the feasibility of acquisition time reduction in MPI-SPECT imaging using deep leering techniques through two main approaches, namely reduction of the acquisition time per projection and reduction of the number of angular projections. Methods: SPECT imaging was performed using a fixed 90° angle dedicated dual-head cardiac SPECT camera. This study included a prospective cohort of 363 patients with various clinical indications (normal, ischemia, and infarct) referred for MPI-SPECT. For each patient, 32 projections for 20 seconds per projection were acquired using a step and shoot protocol from the right anterior oblique to the left posterior...
Solvation free energy and solubility of acetaminophen and ibuprofen in supercritical carbon dioxide: Impact of the solvent model
, Article Journal of Supercritical Fluids ; Volume 109 , 2016 , Pages 166-176 ; 08968446 (ISSN) ; Ghotbi, C ; Jahanbin Sardroodi, J ; Karimi Sabet, J ; Robert, M. A ; Sharif University of Technology
Elsevier
2016
Abstract
Classical molecular dynamics simulations are used to compute the solvation free energy of two pharmaceutical solids, namely ibuprofen and acetaminophen in carbon dioxide (CO2), over the density range of interest in supercritical processes. In order to examine the influence of the solvent model on the resulting free energies, three popular CO2 models (Zhang, EPM2, and TraPPE) are studied. Relatively large discrepancies for the solvation free energy exist between these CO2 models, suggesting that the former is sensitive to the different balances between dispersive and electrostatic forces used in these models. In particular, for the solvation of the highly polar (dipole moment of ∼5.2 Debye)...
Application of response surface methodology for optimization of paracetamol particles formation by RESS method
, Article Journal of Nanomaterials ; Volume 2012 , 2012 ; 16874110 (ISSN) ; Ghotbi, C ; Dorkoosh, F ; Sharif University of Technology
2012
Abstract
Ultrafine particles of paracetamol were produced by Rapid Expansion of Supercritical Solution (RESS). The experiments were conducted to investigate the effects of extraction temperature (313353K), extraction pressure (1018MPa), preexpansion temperature (363403K), and postexpansion temperature (273323 K) on particles size and morphology of paracetamol particles. The characterization of the particles was determined by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Liquid Chromatography/Mass Spectrometry (LC-MS) analysis. The average particle size of the original paracetamol was 20.8m, while the average particle size of paracetamol after nanonization via the...