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Seismic behavior of concrete moment frame reinforced with GFRP bars
, Article Composites Part B: Engineering ; Volume 163 , 2019 , Pages 324-338 ; 13598368 (ISSN) ; Khaloo, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this research, four types of concrete moment frame were designed with glass fiber reinforced polymer (GFRP) bars according to ACI 440.1R-15 and the seismic behavior was assessed using pushover analysis. The frames were three and five stories with two and three bays. A computer code was developed to calculate the amount of fiber reinforced polymer bars in beams of the frames. In order to evaluate nonlinear behavior in plastic hinge regions, sections of beams and columns were analyzed on the basis of moment-curvature diagram and also P-M interaction curve for columns. Performance levels of frames were determined considering ATC-40 criteria. Behavior of concrete moment frames reinforced with...
Effect of compressive glass fiber-reinforced polymer bars on flexural performance of reinforced concrete beams
, Article ACI Structural Journal ; Volume 119, Issue 6 , 2022 , Pages 5-18 ; 08893241 (ISSN) ; Khaloo, A ; Aliasghar Mamaghani, M ; Khaloo, H ; Sharif University of Technology
American Concrete Institute
2022
Abstract
This research studies the effect of glass fiber-reinforced polymer (GFRP) bars as compressive reinforcement in reinforced concrete (RC) beam members. Three singly and six doubly reinforced GFRP-RC beams were tested under a four-point loading configuration. The effect of compressive reinforcement on the load-bearing capacity, ductility, stiffness, and failure mode is determined. Also, the compressive performance of GFRP bars is evaluated by testing GFRP-RC cylinders. According to the results, GFRP bars in compression had a limited contribution to enhancing flexural strength, and the maximum increment in the flexural capacity of doubly reinforced beams compared to singly reinforced specimens...
The effect of direct and cross-rolling on mechanical properties and microstructure of severely deformed aluminum
, Article Journal of Materials Engineering and Performance ; Vol. 23, Issue 1 , 2014 , pp. 115-124 ; ISSN: 10599495 ; Kazeminezhad, M ; Sharif University of Technology
2014
Abstract
Severely deformed commercial pure aluminum sheets by constrained groove pressing are direct and crossrolled. The grain size evolution and dislocation density during rolling are studied using Williamson-Hall analysis on x-ray diffraction patterns of the deformed samples. These results and optical microscopy observations show that subsequent direct or cross-rolling of constrained groove pressed aluminum can produce elongated fine grains. The minimum crystallite size is achieved after cross-rolling of constrained groove pressed samples. By direct-rolling or cross-rolling of annealed sheet, the maximum intensity in x-ray diffraction patterns remains on (200) like annealed aluminum but...
Can a multi-hop link relying on untrusted amplify-and-forward relays render security?
, Article Wireless Networks ; Volume 27 , November , 2020 , pages 795–807 ; Kuhestani, A ; Behroozi, H ; Sharif University of Technology
Springer
2020
Abstract
Cooperative relaying is utilized as an efficient method for data communication in wireless sensor networks and the Internet of Things. However, sometimes due to the necessity of multi-hop relaying in such communication networks, it is challenging to guarantee the secrecy of cooperative transmissions when the relays may themselves be eavesdroppers, i.e., we may face with the untrusted relaying scenario where the relays are both necessary helpers and potential adversary. To obviate this issue, a new cooperative jamming scheme is proposed in this paper, in which the data can be confidentially communicated from the source to the destination through multiple untrusted relays. In our proposed...
Simulating Dynamics of Immiscible Liquids Separation Using Microfluidics
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Aliasghar (Supervisor)
Abstract
Most of industrial and laboratory processes are faced with liquid-liquid emulsions particularly aqueous-organic ones in their different product streams which determine the need to perform phase separation due to enviromental problems or need to increase the product purity. In this project, due to presence of a water-hexane two phase flow mixture in the outflow of a microractor that performs Lithium-Bromine exchange reaction, a capillary microchip separator has been designed in order to separate water through capillary channel and hexane through main channel outlet using interfacial forces and wettability effects. To obtain a desired phase separation, the pressure drop through main channel...
Magneto-mechanical stability of axially functionally graded supported nanotubes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; Mirtalebi, H ; Ahmadian, M. T ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
In this paper, size-dependent vibration analysis of axially functionally graded (AFG) supported nanotubes conveying nanoflow under longitudinal magnetic fields are performed, aiming at performance improvement of fluid-interaction nanosystems. Either the density or the elastic modulus of the AFG nanotube varies linearly or exponentially along the axial direction. Based on the nonlocal continuum theory, the higher-order dynamical equation of motion of the system is derived considering no-slip boundary condition. Galerkin discretization technique and eigenvalue analysis are implemented to solve the modeled equation. The validity of the simplified model is justified by comparing the results with...
Magneto-mechanical stability of axially functionally graded supported nanotubes
, Article Materials Research Express ; Volume 6, Issue 12 , 2019 ; 20531591 (ISSN) ; Mirtalebi, H ; Ahmadian, M. T ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
In this paper, size-dependent vibration analysis of axially functionally graded (AFG) supported nanotubes conveying nanoflow under longitudinal magnetic fields are performed, aiming at performance improvement of fluid-interaction nanosystems. Either the density or the elastic modulus of the AFG nanotube varies linearly or exponentially along the axial direction. Based on the nonlocal continuum theory, the higher-order dynamical equation of motion of the system is derived considering no-slip boundary condition. Galerkin discretization technique and eigenvalue analysis are implemented to solve the modeled equation. The validity of the simplified model is justified by comparing the results with...
Vibration control and manufacturing of intelligibly designed axially functionally graded cantilevered macro/micro-tubes
, Article 13th IFAC Workshop on Intelligent Manufacturing Systems, IMS 2019, 12 August 2019 through 14 August 2019 ; Volume 52, Issue 10 , 2019 , Pages 382-387 ; 24058963 (ISSN) ; Ebrahimi Mamaghani, A ; Ahmadian, M. T ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In the last decade, extensive attention is devoted to intelligibly designed materials of macro/micro-structures containing the fluid flow. In this study, intelligent control and vibrational stability of cantilevered fluid conveying macro/micro-tubes utilizing axially functionally graded (AFG) materials are considered. The governing equation of motion of the system is derived based on modified couple stress theory and then is discretized using Galerkin method. A detailed investigation is carried out to elaborate the influence of various parameters such as material properties, axial compressive load, and Pasternak foundation on the dynamical behavior of the system, all of which are influential...
Synthesis of Silica Nanosheets Using Droplet-based Microfluidics
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Aliasghar (Supervisor)
Abstract
The main purpose of this project is synthesis of the silica nano-sheets by means of microfluidic techniques. Continuous process, precise control of reaction condition, and higher production rate can be considered as main pros of silica nano-sheets synthesized by microfluidic platforms. General method can be explain as follow: first two oleic and aqueous phase are injected to the microfluidic system, then oleic phase breaks down in aqueous phase drop-wisely and by performing sol-gel reaction on the oil-water interface a silica crust is made on oil droplets. Eventually, oil droplets are left the system and broken down and silica nano-sheets are made. FESEM and microscopic images of...
Modeling the correlation between heat treatment, chemical composition and bainite fraction of pipeline steels by means of artificial neural networks
, Article Neural Network World ; Volume 23, Issue 4 , 2013 , Pages 351-367 ; 12100552 (ISSN) ; Pouraliakbar, H ; Mamaghani, K. R ; Khalaj, M. J ; Sharif University of Technology
2013
Abstract
In the present study, bainite fraction results of continuous cooling of high strength low alloy steels have been modeled by artificial neural networks. The artificial neural network models were constructed by 16 input parameters including chemical compositions (C, Mn, Nb, Mo, Ti, N, Cu, P, S, Si, Al, V), Nb in solution, austenitizing temperature, initial austenite grain size and cooling rate over the temperature range of the occurrence of phase transformations. The value for the output layer was the bainite fraction. According to the input parameters in feed-forward back-propagation algorithm, the constructed networks were trained, validated and tested. To make a decision on the completion...
Vibration control and manufacturing of intelligibly designed axially functionally graded cantilevered macro/micro-tubes
, Article 13th IFAC Workshop on Intelligent Manufacturing Systems, IMS 2019, 12 August 2019 through 14 August 2019 ; Volume 52, Issue 10 , 2019 , Pages 382-387 ; 24058963 (ISSN) ; Ebrahimi Mamaghani, A ; Ahmadian, M. T ; Barari A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In the last decade, extensive attention is devoted to intelligibly designed materials of macro/micro-structures containing the fluid flow. In this study, intelligent control and vibrational stability of cantilevered fluid conveying macro/micro-tubes utilizing axially functionally graded (AFG) materials are considered. The governing equation of motion of the system is derived based on modified couple stress theory and then is discretized using Galerkin method. A detailed investigation is carried out to elaborate the influence of various parameters such as material properties, axial compressive load, and Pasternak foundation on the dynamical behavior of the system, all of which are influential...
Covariance Statistic and a Significance Test for Selecting All Active Variables
in Lasso
,
M.Sc. Thesis
Sharif University of Technology
;
Abstract
Testing the significance of the predictor variables and finding an appropriate method for inference on the coefficients is an important question in the sparse linear regression setting. Covariance statistic is a new method that tries to give an answer to this question. This statistic is defined based on lasso fitted values, and when the true model is linear, this statistic has an Exp(1) asymptotic distribution under the null hypothesis (the null being that all truly active variables are contained in the current lasso model). From classical statistics, we have known some methods like chi-squared test for testing the significance of an additional variable between two nested linear models. But...
Using Molecular Dynamics Simulation for Investigation of Sulfuric Compounds Adsorption on Zeolite
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Aliasghar (Supervisor)
Abstract
There are different sulfur compounds in the crude oil, and after combustion all of these sulfuric compounds produce sulfur dioxide, this sulfur dioxide cause acid rain, deactivation of catalysts and also environmental bad effects. So the amount of sulfur that is released should be controlled and this is done by removing sulfuric compounds before combustion. zeolites as adsorbent of sulfuric compounds has been used widely by researches and had given good results. molecular dynamics simulation as an effective way for describing the behavior of these compounds in the molecular level and in scales of angstrom has been used and the effect of van der waals and electrostatic forces between sorbates...
Can a multi-hop link relying on untrusted amplify-and-forward relays render security?
, Article Wireless Networks ; Volume 27, Issue 1 , 2021 , Pages 795-807 ; 10220038 (ISSN) ; Kuhestani, A ; Behroozi, H ; Sharif University of Technology
Springer
2021
Abstract
Cooperative relaying is utilized as an efficient method for data communication in wireless sensor networks and the Internet of Things. However, sometimes due to the necessity of multi-hop relaying in such communication networks, it is challenging to guarantee the secrecy of cooperative transmissions when the relays may themselves be eavesdroppers, i.e., we may face with the untrusted relaying scenario where the relays are both necessary helpers and potential adversary. To obviate this issue, a new cooperative jamming scheme is proposed in this paper, in which the data can be confidentially communicated from the source to the destination through multiple untrusted relays. In our proposed...
Pricing of Service Advance Sale System with Risk Consideration
, M.Sc. Thesis Sharif University of Technology ; Sheikhzadeh, Mehdi (Supervisor)
Abstract
Today service sector is an important part of economy in many countries and it accounts for a great portion of GDP in developed countries. The importance of the service sector has led to an expansion in research worldwide on services. Service has some unique specifications that make it different from product and research in this field is more challenging than production field. Pricing is one of the great challenges in service sector. Due to its intangibility and perishability, managing and pricing of service is complicated and ervice firms consistently seek for method and approaches to better manage their demand, capacity and prices. Advance sale is an effective approach which is commonly...
The Effect of Direct and Cross Rolling on Mechanical Properties and Microstructure of Severely Deformed Aluminium
, M.Sc. Thesis Sharif University of Technology ; Kazeminezhad, Mohsen (Supervisor)
Abstract
Recently, the severe plastic deformation (SPD) is known as one of the most used methods in decreasing the grain size and increasing the strength of metals. In this study, aluminum 1100was subjected toconstrained groove pressing (CGP) at room temperature. The CGPed samples in nanoscale structure, with different CGPed passes were direct rolled and cross-rolled in different rolling strains. Finally, all of the samples were annealed at temperatures of 100, 200 and 300 ° C for 30 min. It was observed that with increasing number of CGP passes and rolling strain the structure became more laminate and finer. With increasing rolling strain, the cross-rolling had greater effect on the microstructure...
Scheduling of Operating Theatre Rooms Considering the Capacity of Post-Operating Rooms
,
M.Sc. Thesis
Sharif University of Technology
;
Salmasi, Nasser
(Supervisor)
Abstract
In this thesis, scheduling of surgery rooms is investigated and the objective is minimizing total patient’s departure time from the ward room in a flexible flow shop manner. Here, some constraints like the capacity of recovery rooms, no-wait motion between the rooms and machine eligibility restrictions ( , Σ ) are considered.For solving this problem,we proposed two mixed integer linear programming models for the research problem. Since the research problem is shown to be NP-complete, we developed several algorithm based on Tabu Search (TS) to heuristically solve it. In TS algorithm two different methods and one neighborhood structures are applied to generate initial solution and...
Optimization of Pulp and Paper Process in Order to Save Energy, Fuel and Capital Investment
, Ph.D. Dissertation Sharif University of Technology ; Farhanieh, Bijan (Supervisor) ; Mozafari, Aliasghar (Supervisor)
Abstract
By applying the Pinch Technology and Exergoeconomic simultaneously, to a complex process system, beneficial and energy-efficient measures are identified.In the present research “Three-link-model” Exergoeconomic methodology optimizes the system and contrary to traditional exergoeconomic methods, reversed method is used. The approach proposed for optimization of such a complex system is to iteratively optimize subsystems. Since assumptions considered by conventional Exergoeconomic for calculating the cost-optimal exergetic efficiency and relative cost difference, are not applicable, new assumptions are to be considered. Unlike traditional Exergoeconomic method, product’s exergetic specific...
Aqueous Phase Reforming of Biomass Using Micro-reactor
, M.Sc. Thesis Sharif University of Technology ; Kazemeini, Mohammad (Supervisor) ; Mohammadi, Aliasghar (Supervisor)
Abstract
Consumption of oil and gas as energy carrier leads to irreversible environmental effects related to greenhouse gases emission. Hence, for the reduction in greenhouse gas emission, a shift to renewable resources for energy supply is recommended. However, in recent years, hydrogen has emerged as the most promising clean energy carrier for generating electrical power through fuel cells. Nevertheless, production of renewable hydrogen is the main barrier to the development of hydrogen as an energy carrier. Aqueous phase reforming of oxygenated hydrocarbon is developed by Dumesic for producing renewable hydrogen-rich gas with low CO. Since it is expected that, use of new technology such as the...
Seismic Performance Evaluation of Moment Frame Using Concrete Beams Reinforced with FRP Bars
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Today, many evidences, including the distribution of galactic velocities, gravitational lensing observations, and the cosmic microwave background, show that there exist dark matter (non-baryon matter) in large-scale cosmological structures that are stable, free of charge and without color, which has gravitational interaction like normal matter. The hypothesis that weakly interacting massive particles (WIMPs) as a dark matter candidate with mass range of several tens of GeV to several teV and with the typical couplings of Electroweak order of magnitude, is an attractive and desirable model, Which naturally explains the density of cosmic dark matter in agreement with observations. Alongside...