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behavioral-research
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Seismic analysis of steel liquid storage tanks by Endurance Time method
, Article Thin-Walled Structures ; Volume 50, Issue 1 , January , 2012 , Pages 14-23 ; 02638231 (ISSN) ; Alembagheri, M ; Sharif University of Technology
Abstract
Endurance Time (ET) method is a time history based method for seismic evaluation of structures using intensifying dynamic excitation as the loading function. In this paper, application of this method in the analysis of steel tanks has been investigated. A methodology for practical application of ET method in seismic assessment of storage tanks has been presented. This methodology has been applied in three-dimensional nonlinear analysis of a particular anchored steel tank using Finite Element method, and results are compared with conventional codified design procedures. Results of the analyses indicate reasonable accuracy of the proposed method in estimation of seismic responses of steel...
Aging behaviors of Al 6061 and Al 6061/ SiCp composite
, Article Advanced Materials Research ; Volume 410 , 2012 , Pages 240-244 ; 10226680 (ISSN) ; 9783037853160 (ISBN) ; Ekrami, A ; Seyed Reihani, S. M ; Mousavi Abarghouie, S. M. R ; Sharif University of Technology
2012
Abstract
In the present research the aging behavior of Al6061 alloy and Al6061/SiCp composite fabricated by powder metallurgy method was investigated. The solution treatment of the samples were carried out at 527°C for 2, 3and 4 h followed by aging at 180°C for different aging times between 1 and 10 h. The existence of SiC particles led to increasing the peak hardness of the composite. The peak hardness of the composite took place at shorter times than that of the 6061 alloy for the samples solution treated for 3and 4 h, but took place at longer times for the samples solution treated for 2 h. The optimum solution treating time was about 3 h for both the composite and the 6061 alloy that led to the...
Molecular dynamics investigation of β-SiC behavior under three-axial tensile loading
, Article Journal of Computational and Theoretical Nanoscience ; Volume 8, Issue 11 , 2011 , Pages 2187-2192 ; 15461955 (ISSN) ; Simchi, A ; Besharati Givi, M. K ; Rajabpour, A ; Sharif University of Technology
2011
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...
Design of tensegrity structures for supporting deployable mesh antennas
, Article Scientia Iranica ; Volume 18, Issue 5 , October , 2011 , Pages 1078-1087 ; 10263098 (ISSN) ; Abedian, A ; Sharif University of Technology
2011
Abstract
This paper is an attempt to develop a design methodology for a special deployable structure for potential use in micro-satellites. The basic form of this structure is a hexagonal prismatic tensegrity structure, which, after being rigidified, is used as the supporting structure of a mesh-like antenna. Here, the objectives of presenting the design methodology are to prevent structural elements from failure, while maintaining the structural natural frequency and mesh tension above an intended value and in addition, to minimize the overall mass. Here, the suggested design strategy combines the need for a behavioral study (i.e. fast and wide range evaluation) at the beginning of the design, with...
Crystallization kinetics of glass-ceramics by differential thermal analysis
, Article Ceramics - Silikaty ; Volume 55, Issue 2 , May , 2011 , Pages 188-194 ; 08625468 (ISSN) ; Nemat, A ; Nozad, A ; Hamnabard, Z ; Baghshah, S ; Sharif University of Technology
2011
Abstract
The crystallization behavior of fluorphlogopite, a glass-ceramic in the MgO-SiO2-Al2O3-K2O-B 2O3-F system, was studied by substitution of Li 2O for K2O in the glass composition. DTA, XRD and SEM were used for the study of crystallization behavior, formed phases and microstructure of the resulting glass-ceramics. Crystallization kinetics of the glass was investigated under non-isothermal conditions, using the formal theory of transformations for heterogeneous nucleation. The crystallization results were analyzed, and both the activation energy of crystallization process as well as the crystallization mechanism were characterized. Calculated kinetic parameters indicated that the appropriate...
An optimal approach to synchronize non-identical chaotic circuits: An experimental study
, Article International Journal of Circuit Theory and Applications ; Volume 39, Issue 9 , 2011 , Pages 947-962 ; 00989886 (ISSN) ; Haeri, M ; Sharif University of Technology
Abstract
The control signal magnitude and energy are among the limiting and therefore important factors to be addressed in the practical applications of a synchronization scheme. In this paper, we present an algorithm to find control parameters in an active sliding mode controller in order to reduce the control effort in synchronizing non-identical chaotic systems. We also determine uncertainties bound on the systems dynamics for which the calculated control parameters still guarantee the occurrence of the sliding motion of the error states. The proposed controller was practically applied on an experimental setup, consisting of two chaotic circuits, which resembles Chen and Lu systems behavior....
Non-linear vibration of dagger-shaped atomic force microscope cantilevers by considering the Hertzian contact theory
, Article Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics ; Volume 225, Issue 2 , 2011 , Pages 77-94 ; 14644193 (ISSN) ; Zohoor, H ; Sharif University of Technology
2011
Abstract
The non-linear flexural vibration for a dagger-shaped atomic force microscope cantilever has been investigated using the Timoshenko beam theory. In this article, the normal and tangential tip-sample interaction forces are found from Hertzian contact model and the effects of the geometry, normal and lateral contact stiffness, height of the tip, thickness of the beam, the angle between the cantilever and the sample surface and breadth and height taper ratios on the non-linear frequency to linear frequency ratio have been studied. The differential quadrature method (DQM) is employed to solve the non-linear differential equations of motion. The results show that the softening behaviour is seen...
Small signal circuit modeling for semiconductor self-assembled quantum dot laser
, Article Optical Engineering ; Volume 50, Issue 3 , 2011 ; 00913286 (ISSN) ; Faez, R ; Sharif University of Technology
Abstract
In this paper, for the first time, we present a small signal circuit model of InGaAs/GaAs self-assembled quantum dot (QD) laser, based on the standard rate equations. By using the presented model, modulation response of QD laser is investigated. The simulation results show that retarded carrier relaxation due to phonon bottleneck degrades the modulation and impulse responses of a QD laser. It is shown that modulation bandwidth is increased with larger inhomogeneous broadening. Also, our model describes the effects of carrier recombinations inside and outside of a QD region, on the modulation response behavior
Adaptive characterisation of a human hand model during intercations with a telemanipulation system
, Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 688-693 ; 9781467372343 (ISBN) ; Sadeghnejad, S ; Farahmand, F ; Vosoughi, G ; Sharif University of Technology
2015
Abstract
Proper modeling of the human arm dynamic, as it interacts with telemanipulation and haptic systems, is important in enhancing the transparency of these systems. In this article, we introduced an adaptive identifier to estimate the impedance characteristic of a human operator as it interacts with a single translational degree of freedom mechanism. The five parameter model, including an extra spring and damper for a better approximation of the dynamic behavior of human arm, has been used. Since the impedance characteristic of human arm differs from one individual to another, it is important to estimate these parameters for each individual and update the controller to enhance the transparency...
A prioritization model for locating relief logistic centers using analytic hierarchy process with interval comparison matrix
, Article Knowledge-Based Systems ; Volume 86 , September , 2015 , Pages 173-181 ; 09507051 (ISSN) ; Asvadi, S ; Sharif University of Technology
Elsevier
2015
Abstract
When natural disasters happen, relief logistic centers (RLCs) and the quality of their services become absolutely important. In other words, choosing proper locations for RLCs has a direct impact on operating costs and timeliness of responses to the rising demands. This paper aims at proposing a decision support system for prioritizing RLC's locations to facilitate providing emergency helps when natural disasters occur. The present study, focuses on considering availability, risk, technical issues, cost and coverage in locating RLCs. It is assumed that applying analytic hierarchy process (AHP) can facilitate the problem of locating these centers. The most important step in this process is...
A new double input-double output complex envelope amplifier behavioral model taking into account source and load mismatch effects
, Article IEEE Transactions on Microwave Theory and Techniques ; Volume 63, Issue 2 , 2015 , Pages 766-774 ; 00189480 (ISSN) ; Banai, A ; Pedro, J. C ; Sharif University of Technology
Abstract
This paper presents a double input-double output bilateral low-pass equivalent amplifier behavioral model that takes into account input source and output load termination mismatches. The model is intended for the system-level simulation of amplifier chains subjected to wideband modulated signals, since it can predict the device's input and output scattered waves and their memory effects, in a wide range of voltage standing wave ratios (VSWR). In addition, the model extraction methodology, and its associated laboratory test bench are discussed, noting the limitations of conventional setups for behavioral model extraction and validation. The model is validated comparing the predicted and...
A study on seismic behavior of buried steel pipelines crossing active faults
, Article Pipelines 2010: Climbing New Peaks to Infrastructure Reliability - Renew, Rehab, and Reinvest - Proc. of the Pipelines 2010 Conference ; Volume 386 , 2010 , Pages 1-12 ; 9780784411384 (ISBN) ; Bakhshi, A ; Sharif University of Technology
2010
Abstract
Some known phenomena which cause a buried steel pipeline to fail are large ground motion and landside. Thus, many researchers have studied pipelines behavior against those phenomena with simplified assumptions in which effects of interaction between soil and pipe are not considered as well. In this study, the behavior of a pipe through Normal and Strike slip faults and contact between them are simulated close to reality with the powerful software of ABAQUS. The results from a parametric analysis on effects of those faults on buried steel pipelines show that increasing the angle between the pipe axis and fault plane (up to 90°), as well as the pipe thickness, and decreasing the burial depth...
Behavior-based acceleration commanded formation flight control
, Article ICCAS 2010 - International Conference on Control, Automation and Systems 2010, Article number 5670304, Pages 1340-1345 ; 2010 , Pages 1340-1345 ; 9781424474530 (ISBN) ; Saghafi, F ; Sharif University of Technology
2010
Abstract
In this paper, the design of a formation flight controller is investigated. Each vehicle in the formation is controlled by designing two separate control loops. The formation flight controller placed in the outer loop employs behavior-based control as a distributed control strategy to steer the vehicle by producing acceleration commands and the control system placed in the inner loop is to convert these commands to the actuator commands. Leader following architecture is applied to define the structure for the formation flight. To study the pragmatic issues of the proposed formation flight controller, it is implemented into multiple micro air vehicles which are modeled by a...
Modeling of tail dynamic behavior and trajectory control of a fish-robot using fuzzy logic
, Article 2010 IEEE International Conference on Robotics and Biomimetics, ROBIO 2010, 14 December 2010 through 18 December 2010 ; 2010 , Pages 885-890 ; 9781424493173 (ISBN) ; Dehghani, M. R ; Alasty, A ; Sharif University of Technology
Abstract
To have a complete model of a thunniform Fish-Robot, models of both body and tail are required. The dynamic model of the body is developed according to the parameters of a thunniform Fish-Robot built in MIT University, while, as the main part of this paper, the dynamic model of the tail is developed using fuzzy logic. Using experimental data and table look-up scheme, a fuzzy black box is introduced that gives the value of thrust force generated for any value of the Fish-Robot's input parameters: frequency of tail oscillation, amplitude of tail oscillation and speed of the Fish-Robot. In the second part, a trajectory fuzzy controller is designed for the Fish-Robot. The output of trajectory...
Adaptive critic-based neuro-fuzzy controller in multi-agents: Distributed behavioral control and path tracking
, Article Neurocomputing ; Volume 88 , July , 2012 , Pages 24-35 ; 09252312 (ISSN) ; Etemadi, S ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
Abstract
In this paper, we follow two control tasks in a leader following frame with undirected network and local communications. As the first goal, distributed behavioral imitation, which is necessary to fit agents with complicated motion equations in kinematic frames, is discussed. Providing real agents with behavioral controller makes them capable to act as a kinematic particle. The second goal is to design an active leading strategy for the LA to move the group on a predefined path. Both problems can be mathematically modeled in an affine form, which is the reason behind using a unique adaptive controller to solve them. The controller is based on a neuro-fuzzy structure with critic-based leaning...
Qualitative study of nanoassembly process: 2-D molecular dynamics simulations
, Article Scientia Iranica ; Volume 17, Issue 1 F , 2010 , Pages 1-11 ; 10263098 (ISSN) ; Meghdari, A ; Jalili, N ; Amiri, F ; Sharif University of Technology
2010
Abstract
Precise positioning of nanoclusters through manipulation in the presence of other clusters is one of the main challenging tasks in nanoclusters assembly. Currently, the size of clusters which are used as building blocks is decreasing to a few nanometers. As a result, the particle nature of the matter has a crucial role in manipulator/cluster/substrate interactions. In order to understand and predict the behavior of nanoclusters during the positioning process, it is, therefore, essential to have a deep insight into the aforementioned nanoscale interactions, in this research, 2-D molecular dynamics simulations are used to investigate such behaviors. Performing the planar simulations can...
Effects of tip mass and interaction force on nonlinear behavior of force modulation FM-AFM cantilever
, Article Journal of Mechanics ; 2016 , Pages 1-12 ; 17277191 (ISSN) ; Zohoor, H ; Habibnejad Korayem, M ; Sharif University of Technology
Cambridge University Press
2016
Abstract
Influences of the tip mass, excitation mode of Frequency Modulated Atomic Force Microscope (FM-AFM) on the resonance frequency shift in force modulation (FM) mode are studied. Governing equations of motion are determined based on Timoshenko beam model with concentrated end mass. Approach point and base amplitude are set such that the FM-AFM remains just in FM mode. Either the linearized and nonlinear Derjaguin-Muller-Toporov (DMT) model are investigated. Then frequency shifts are determined for various interaction force regimes. It is showed the effect of tip mass on frequency shift is significant even for small tips. Nonlinear model shows lower frequency shifts in comparison with linearized...
Effects of tip mass and interaction force on nonlinear behavior of force modulation fm-afm cantilever
, Article Journal of Mechanics ; Volume 33, Issue 2 , 2017 , Pages 257-268 ; 17277191 (ISSN) ; Zohoor, H ; Habibnejad Korayem, M ; Sharif University of Technology
Cambridge University Press
2017
Abstract
Influences of the tip mass, excitation mode of Frequency Modulated Atomic Force Microscope (FM-AFM) on the resonance frequency shift in force modulation (FM) mode are studied. Governing equations of motion are determined based on Timoshenko beam model with concentrated end mass. Approach point and base amplitude are set such that the FM-AFM remains just in FM mode. Either the linearized and nonlinear Derjaguin-Muller-Toporov (DMT) model are investigated. Then frequency shifts are determined for various interaction force regimes. It is showed the effect of tip mass on frequency shift is significant even for small tips. Nonlinear model shows lower frequency shifts in comparison with linearized...
Optimal zonal fast-charging station placement considering urban traffic circulation
, Article IEEE Transactions on Vehicular Technology ; Volume 66, Issue 1 , 2017 , Pages 45-56 ; 00189545 (ISSN) ; Sadeghi Barzani, P ; Sharif University of Technology
Abstract
Fast-charging stations are connected to the electric grid and can fully charge an electric vehicle (EV) in less than half an hour. The capacity and location of the charging stations bring the costs to the electric grid operator, as well as to the station owner and EV user. A zonal approach has been proposed in this paper to determine the optimal place and capacity of fast-charging stations. Station development cost and the expected costs incurred by the EV user and the grid operator due to EV charging have also been included in the proposed approach. The geographic characteristics associated with the electric substations, urban roads, and city zones have also been considered in the proposed...
Assessing the relationship between heavy vehicle driver sleep problems and confirmed driver behavior measurement tools in Iran
, Article Transportation Research Part F: Traffic Psychology and Behaviour ; Volume 59 , 2018 , Pages 57-66 ; 13698478 (ISSN) ; Nassiri, H ; Sahebi, S ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Road traffic crashes have become an important public health problem. By studying the statistics of heavy vehicle crashes in the world, it becomes obvious that although heavy vehicle drivers experience fewer crashes than private car drivers, a large percentage of heavy vehicle crashes leads to death. So, it is important to identify the driving characteristics of heavy vehicle drivers. In this study, 474 Iranian truck drivers were interviewed face to face. Response rate of the survey was 80%, the participants who answered the questions on two behavioral questionnaires: Driver Behavior Questionnaire (DBQ) and Attention-Related Driving Error Scale (ARDES). Also, two sleep assessing...