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ultrasonic-wave
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Synthesis of Polycyclic Heterocycles using Benzofuranone Scaffolds via 1,3-Dipolar Cycloaddition Reactions under Green Chemistry Conditions
, Ph.D. Dissertation Sharif University of Technology ; Matloubi Moghaddam, Firouz (Supervisor) ; Foroumadi, Alireza (Co-Supervisor)
Abstract
Spirooxindole compounds are naturally occurring compounds and have significant biological activities due to their unique spatial structure. Spirooxindole compounds, especially spiro oxindoles containing acyclic ring at C-3 position of oxindole, have high interaction capability with large productions. Therefore, these compounds are important in medicinal chemistry. The method used for the synthesis of spirooxindole compounds has been introduced. In general, for the synthesis of these compounds, isatin derivatives are used in 1 and 3 dipolar reactions in the presence of various solvents and catalysts. Due to the presence of quaternary spiro carbon with sp3 hybridization in the structure of...
Durability Evaluation and Health Monitoring of Microcracked Slag-Based Geopolymer Concrete Due to Step by Step Pressure Loading
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor) ; Toufigh, Vahab (Co-Supervisor)
Abstract
The goal of this research is to study the effect of local microcracking due to step by step pressure loading on the durability properties of geopolymer concrete. To better understand the behavior of GGBS-based GPC under different pressure stress levels, some experiments such as water permeability and water absorption conducted on the samples at each state of damage. Also, non-destructive tests such as ultrasonic waveform and pulse velocity (UPV) was used to quantify the extent of damage at each step. GGBFS and a blend of sodium silicate solution and 10 molar sodium hydroxide solution with SSSH⁄ ratio of 2 were used for production of GPC samples. GPC, OGPC and OPC samples with water to binder...
Investigating the effects of vibration method on ultrasonic-assisted drilling of Al/SiCp metal matrix composites
, Article Robotics and Computer-Integrated Manufacturing ; Vol. 30, issue. 3 , 2014 , Pages 344-350 ; ISSN: 07365845 ; Akbari, J ; Yousefi, R ; Rahi, A ; Nick, M. G ; Sharif University of Technology
Abstract
Preciseness and finished surface quality are the significant factors of final products, especially in a number of drilling processes. Burr is usually considered a negative outcome in assembly procedures. One way to reduce or remove burr and improve surface roughness in metal cutting is to employ ultrasonic vibration in the drilling process. In this paper, the effects of ultrasonic vibration on burr size reduction, drilling force and surface roughness with two different vibration systems are investigated. To this end, two vibration structures were built, one to excite the workpiece (the workpiece vibration system) and the other to vibrate the tool (the tool vibration system). Besides, the...
Fatigue damage detection in large thin wall plate based on ultrasonic guided wave by using a piezoelectric sensor network
, Article 29th Congress of the International Council of the Aeronautical Sciences, ICAS 2014 ; 2014 ; Abedian, A ; Sharif University of Technology
Abstract
Today, structural Health monitoring is a major concern in the engineering community. Multisite fatigue damage, hidden cracks and corrosion in hard-to-reach locations are among the major flaws encountered in today's extensive diagnosis and/or prognosis of aircraft structures. Ultrasonic waves, lamb waves are particularly advantageous because of their propagation at large distances with little damp in thin-wall structures. In this paper a new rectangular shape array of embedded piezoelectric sensors is developed to detect some damages in large planar structures. An artificial neural network is trained to identify the damage state and its location. Output signals of each sensor due to various...
Investigating the role of ultrasonic wave on two-phase relative permeability in a free gravity drainage process
, Article Scientia Iranica ; Vol. 21, issue. 3 , 2014 , p. 763-771 ; Karimi, R ; Najafi, I ; Ghazanfari, M. H ; Ghotbi, C ; Sharif University of Technology
Abstract
In this work, the process of free gravity drainage under the influence of ultrasonic waves was investigated. A glass bead pack porous medium was used to perform free fall gravity drainage experiments. The tests were performed in the presence and absence of ultrasonic waves, and the data of recovery were recorded versus time under both conditions. The wetting phase relative permeability curves were obtained using the data of recovery versus time, based on the Hagoort backward methodology. Subsequently, using the wetting phase relative permeability curve, the relative permeability of non-wetting phases were calculated by performing history matching to the experimental production data. The...
Applying ultrasonic vibration to decrease drilling-induced delamination in GFRP laminates
, Article Procedia CIRP, Leuven ; Volume 6 , April , 2013 , Pages 577-582 ; 22128271 (ISSN) ; Baghlani, V ; Akbari, J ; Bushroa, A. R ; Mardi, N. A ; Sharif University of Technology
2013
Abstract
Delamination is a major problem in drilling of fiber-reinforced composite materials. Thrust force is an important factor leading to propagation of delamination during drilling process. One of effective methods to reduce machining forces is application of ultrasonic vibrations. In this study ultrasonic assisted drilling is applied to reduce thrust force in drilling of GFRP laminates. In order to conduct experiments a setup is designed and fabricated to apply both vibrations and rotation to drill bits. Using Taguchi method, a set of experiments is conducted with feed rate, spindle speed, and ultrasonic vibration amplitude as control factors. The results show that applying ultrasonic vibration...
Modeling the kinetics of asphaltene flocculation in toluene-pentane systems for the case of sonicated crude oils
, Article Scientia Iranica ; Volume 20, Issue 3 , June , 2013 , Pages 611-616 ; 10263098 (ISSN) ; Tavakolian, M ; Najafi, I ; Ghazanfari, M. H ; Taghikhania, V ; Amani, M ; Sharif University of Technology
2013
Abstract
This work is concerned with the monitoring of ultrasound effects on inhibition, as well as the reversible kinetics modeling of asphaltene flocculation in toluene-n-alkane systems, which has been rarely reported in the literature. A crude oil sample was exposed to ultrasound waves, and then the colloidal structural evolutions of flocculated asphaltene particles induced by addition of n-alkane were studied, using a confocal microscopy. Observations confirmed that radiation of ultrasound can change the irreversibility of asphaltene flocculation in crude oil. To interpret the kinetics of asphaltene flock aggregation, the Smoluchowski model was used, and the time dependent size distribution of...
Ultrasonic-assisted cylindrical grinding of Alumina-zirconia ceramics
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 2 A , Volume 2 A , 2013 ; 9780791856185 (ISBN) ; Akbari, J ; Zahedi, A. M ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2013
Abstract
Due to its vast applications and stochastic nature, grinding has been the subject of investigations and modifications for decades. Applying ultrasonic vibration in grinding has been a successful innovation introducing benefits such as reduced forces and temperature, improved surface quality, and making higher removal rates possible. In this work a set-up is developed for utilizing ultrasonic vibrations in cylindrical grinding. This is done by rotating and simultaneously vibrating the workpiece material. The set-up is used for cylindrical grinding of Alumina-zirconia ceramic as a difficult-to-grind and widely used industrial ceramic. Optimized parameters for efficient grinding and surface...
Finding tuning frequency for symmetric and anti-symmetric lamb waves using FEM
, Article Export | Download | More... 28th Congress of the International Council of the Aeronautical Sciences 2012, ICAS 2012 ; Volume 3 , 2012 , Pages 2412-2416 ; 9781622767540 (ISBN) ; Moosavi, M. R ; Abedian, A ; Golzad, I ; Sharif University of Technology
2012
Abstract
In the area of life assessment, none-destructive methods of inspection and evaluation (NDI/NDE) play important role to ensure if astructure is still healthy enough to get used of. Using ultrasonic stress waves is one of the easiest and cheapest methods of NDI. Accordingly, different modes of lamb wave are mostly of interest..There are various methods for generating lamb waves. One of these methods is using piezoelectric wafer actuator/sensors (PWAS). Accordingly, one of the most important parts of this method is to generate right mode via an appropriate choose of actuating frequency. In this text using a new method for finding tuning frequencies of different lamb wave modes proposed. For...
Wavelet-based active sensing for quantitative assessment of through-thickness crack size and angle in composite plates
, Article 28th Congress of the International Council of the Aeronautical Sciences 2012, ICAS 2012 ; Volume 3 , 2012 , Pages 2417-2424 ; 9781622767540 (ISBN) ; Ekhtiari, M ; Abedian, A ; Sharif University of Technology
2012
Abstract
Cost-effective and reliable damage detection is critical for utilization of composite materials. This paper utilizes PZT piezoelectric disks to excite the first symmetric Lamb wave (S0 mode). The interaction of Lamb wave mode with a through-thickness crack of different lengths and angles in [0/45/-45/90]s CF/EP laminate plates is analyzed in terms of finite element method. This study contributes to the damage detection by developing an improved wavelet-based signal processing technique that enhances the visibility and interpretation of the Lamb wave signals related to defects. Based on the amount of energy dissipated by the damage, a damage index is defined as the function of an electric...
Ultrasonic-assisted grinding of Ti6Al4V alloy
, Article Procedia CIRP ; Volume 1, Issue 1 , 2012 , Pages 353-358 ; 22128271 (ISSN) ; Movahhedy, M. R ; Akbari, J ; Sharif University of Technology
2012
Abstract
In conventional grinding of hard to cut materials such as Ti6Al4V alloys, surface burning, redeposition and adhesion of chips to the grinding wheel and workpeice occur visibly unless it is carried out at low speeds and with high volume of cutting fluid. Ultrasonic assisted grinding is an efficient machining process which improves the machinability of hard-to-cut materials by changing the kinematics of the process. In this research, the effect of imposition of ultrasonic vibration on the grinding of Ti6Al4V alloy is studied. Longitudinal vibration at ultrasonic frequency range (20 kHz) is applied on the workpiece and machining forces and surface roughness are compared between conventional...
Comparison of ultrasonic wave radiation effects on asphaltene aggregation in toluene-pentane mixture between heavy and extra heavy crude oils
, Article Journal of Energy Resources Technology, Transactions of the ASME ; Volume 134, Issue 2 , 2012 ; 01950738 (ISSN) ; Najafi, I ; Ghazanfari, M. H ; Amani, M ; Sharif University of Technology
2012
Abstract
In this study, it is aimed to compare the efficiency of ultrasonic wave technology on asphaltene flocculation inhibition of crude oils with different American Petroleum Institute (API) gravities. A set of confocal microscopy test is performed and a series of statistical analysis is done. According to the results of this study, there is an optimum radiation time for both crudes at which the viscosity and the flocculation rate of asphaltenic crude oils reduces to its minimum. This optimum appears at later times of radiation for extra heavy oil. Also, it is shown that the rate of changes in the properties measured in this study is sharper for extra heavy crude oil. It could be concluded that...
The finite element simulation of lamb wave propagation in a cracked structure with coupled filed elements
, Article Advanced Materials Research, 7 January 2012 through 8 January 2012 ; Volume 463-464 , January , 2012 , Pages 618-623 ; 10226680 (ISSN) ; 9783037853634 (ISBN) ; Abedian, A ; Khajehtourian, R ; Singapore Institute of Electronics (SIE); Science and Engineering Institute (SCIEI) ; Sharif University of Technology
2012
Abstract
Crack detection by Piezoelectric Wafer Active Sensors (PWAS) is one of the emerging methods of Non-destructive Evaluation (NDE). These sensors can assess the health state of the structure in far filed through the analyzing the high frequency Lamb wave propagation. As PWAS is the essential part of this method, simulation and modeling of these sensors and their interaction with the host structure, strongly affect the accuracy of results. In this study, unlike the previous works, in which some certain areas of the host structure were considered as a sensor and actuator, the direct simulation of electro-mechanical interaction of the PWAS and the host structure is modeled among modeling the PWAS...
Burr size reduction in drilling of Al/SiC metal matrix composite by ultrasonic assistance
, Article Advanced Materials Research, 15 December 2011 through 18 December 2011 ; Volume 410 , December , 2012 , Pages 279-282 ; 10226680 (ISSN) ; 9783037853160 (ISBN) ; Yousefi, R ; Akbari, J ; Rahi, A ; Nikouei, S. M ; Sharif University of Technology
Abstract
Metal matrix composites (MMCs) have received considerable attention due to their excellent engineering properties. Accuracy and surface finish play an important role in modern industry. Undesired projections of materials, known as burrs, reduce the part quality and negatively affect the assembly process. In this study, reducing burr size in drilling of MMC is performed by adding ultrasonic vibration to the process. Al/SiC p MMC with 5 wt% of SiC particulates in dry drilling operation with HSS drill tools coated with TiN was investigated. The effect of ultrasonic assistance on burr size was studied. The results demonstrate that under suitable ultrasonic vibration conditions, in comparison...
Application of ultrasonic wave technology as an asphaltene flocculation inhibition method
, Article Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources ; 2012 ; Amani, M ; Mousavi, M. R ; Ghazanfari, M. H ; Sharif University of Technology
Abstract
Based on series of crude oil rheological properties and asphaltene flocculation confocal microscopy analysis, Najafi et al., (2011) reported the existence of an optimum radiation time at which asphaltenic crude oils reach the minimum kinematic viscosity. Accordingly, they proposed the idea of asphaltene flocculation inhibition due to wave radiation.The present investigation is a continuous effort to provide more information about the process of flocculation inhibition. Confocal microscopy and rheological analyses are performed on different crude oils to prove the repeatability of the observed phenomena. The asphaltene content analysis was done based on IP143 procedure, which provides more...
Ultrasound dosimetery using microbubbles
, Article IFMBE Proceedings, 20 June 2011 through 23 June 2011 ; Volume 35 IFMBE , June , 2011 , Pages 359-362 ; 16800737 (ISSN) ; 9783642217289 (ISBN) ; Zahedi, E ; Tavakkoli, J ; Sharif University of Technology
2011
Abstract
In this paper, a new technique based on nonlinear resonance of microbubbles is investigated in order to estimate the amplitude of an ultrasound wave pressure field. First, the existing theoretical model is reviewed. Then, an experimental setup consisting of a bubble generator and transmitting/receiving ultrasound transducers operating in the 1 MHz frequency range is described. The effect of background noise is also taken into account. Results show that the second harmonic oscillations are detectable, paving the way to develop a quantitative method for in vivo calibration of ultrasound waves
Quantifying the role of ultrasonic wave radiation on kinetics of asphaltene aggregation in a toluene-pentane mixture
, Article Petroleum Science and Technology ; Volume 29, Issue 9 , 2011 , Pages 966-974 ; 10916466 (ISSN) ; Mousavi, S. M. R ; Ghazanfari, M.H ; Ghotbi, C ; Ramazani, A ; Kharrat, R ; Amani, M ; Sharif University of Technology
Abstract
Recently, ultrasonic wave technology has received much attention as a method for removal of asphaltene deposits from the near wellbore region. However, very little is known about another feature of this technology on the kinetics of asphaltene molecules aggregation. In this work, the kinetics of asphaltene flocculation in several crude oil samples exposed to ultrasonic waves for different time intervals is studied by confocal microscopy. The colloidal structural evolutions of flocks are described by analysis of size distribution of flocculated asphaltene particles. The results show that for the first 90 min of flocculation time, the size of aggregates increases rapidly, and a...
A mathematical and experimental analysis of role of ultrasonic wave radiation on relative permeabilties in gravity drain
, Article 73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 ; Volume 7 , May , 2011 , Pages 5104-5108 ; 9781617829666 (ISBN) ; Keshavarzi, B ; Ghazanfari, M ; Ghotbi, C ; Amani, M ; Sharif University of Technology
Society of Petroleum Engineers
2011
Abstract
This work concerns with experimental and analytical investigation of role of ultrasonic wave radiation in relative permeability of both wetting and non-wetting phases in a free gravity drainage process in porous media under the influence of ultrasonic wave. Glass beads ranged from 70 to 100 mesh sizes were packed and used in the tests. The working fluids consist of distilled water, kerosene and Doroud and Paidar crude oils as wetting and air as non-wetting phase. The measured oil recovery data along with Hagoort (1984) backward methodology were used to determine and to compare the relative permeability of wetting phases in presence and absence of ultrasonic radiation. In addition, the...
A mode conversion-based algorithm for detecting rectangular notch parameters in plates using Lamb waves
, Article Archive of Applied Mechanics ; Volume 85, Issue 6 , 2015 , Pages 793-804 ; 09391533 (ISSN) ; Behzad, M ; Mirdamadi, H. R ; Sharif University of Technology
Springer Verlag
2015
Abstract
In this paper, an algorithm for identifying rectangular notch parameters as damage in a plate using Lamb waves is presented. In this algorithm, a combination of pulse-echo and pitch-catch methods is used. The method is divided into two steps: notch localization and notch geometry detection. The bases for this algorithm are mode conversion and scattering phenomena because of interaction of Lamb wave modes with defects. The method is applied to some numerical examples, and the results show that it can successfully identify all of rectangular notch parameters, i.e., its location, depth, and width
Chemometric-based determination of polycyclic aromatic hydrocarbons in aqueous samples using ultrasound-assisted emulsification microextraction combined to gas chromatography-mass spectrometry
, Article Journal of Chromatography A ; Volume 1413 , September , 2015 , Pages 117-126 ; 00219673 (ISSN) ; Sereshti, H ; Parastar, H ; Sharif University of Technology
Elsevier
2015
Abstract
In the present research, ultrasonic-assisted emulsification-microextraction (USAEME) coupled with gas chromatography-mass spectrometry (GC-MS) has been proposed for analysis of thirteen environmental protection agency (EPA) polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Tetrachloroethylene was selected as extraction solvent. The main parameters of USAEME affecting the efficiency of the method were modeled and optimized using a central composite design (CCD). Under the optimum conditions (9 μL for extraction solvent, 1.15% (w/v) NaCl (salt concentration) and 10min for ultrasonication time), preconcentration factor (PF) of the PAHs was in the range of 500-950. In order to have a...