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dehghani-ashkezari--h
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Real Time Simulation of Grasping Procedure of Large Internal Organs during Laparoscopic Surgery
,
M.Sc. Thesis
Sharif University of Technology
;
Farahmand, Farzam
(Supervisor)
;
Firoozbakhsh, Keikhosrow
(Supervisor)
Abstract
Surgical simulation systems facilitate a safe and efficient training process by providing a virtual environment in which the trainee can repeat the surgical procedure unlimitedly at different situations. The present study attempted to provide a real time simulation for the grasping procedure of a large internal organ during laparoscopic surgery. A mass-spring-damper model was employed to simulate the nonlinear viscoelastic large deformations of spleen tissue interacting with a triple-jaw large organ grasper. A novel collision detection algorithm was designed and implemented to determine the contact points between the tissue and the grasper jaws. The boundary conditions imposed at the contact...
Real time simulation of grasping procedure of large internal organs during laparoscopic surgery
, Article Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ; Volume 2012 , 2012 , Pages 924-927 ; 1557170X (ISSN) ; Mirbagheri, A ; Farahmand, F ; Behzadipour, S ; Firoozbakhsh, K ; Sharif University of Technology
2012
Abstract
Surgical simulation systems facilitate safe and efficient training processes of surgical trainees by providing a virtual environment in which the surgical procedure can be repeated unlimitedly in a wide variety of situations. The present study attempted to develop a real time simulation system for the grasping procedure of large internal organs during laparoscopic surgery. A mass-spring-damper model was developed to simulate the nonlinear viscoelastic large deformations of the spleen tissue while interacting with a triple-jaw grasper. A novel collision detection algorithm was designed and implemented to determine the contact points between the tissue and the grasper jaws. Force or...
Real time simulation of grasping procedure of large internal organs during laparoscopic surgery
, Article Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ; 2012 , Pages 924-927 ; 1557170X (ISSN) ; 9781424441198 (ISBN) ; Mirbagheri, A ; Farahmand, F ; Behzadipour, S ; Firoozbakhsh, K ; Sharif University of Technology
2012
Abstract
Surgical simulation systems facilitate safe and efficient training processes of surgical trainees by providing a virtual environment in which the surgical procedure can be repeated unlimitedly in a wide variety of situations. The present study attempted to develop a real time simulation system for the grasping procedure of large internal organs during laparoscopic surgery. A mass-spring-damper model was developed to simulate the nonlinear viscoelastic large deformations of the spleen tissue while interacting with a triple-jaw grasper. A novel collision detection algorithm was designed and implemented to determine the contact points between the tissue and the grasper jaws. Force or...
Integrating hydrodynamic and acoustic cell separation in a hybrid microfluidic device: a numerical analysis
, Article Acta Mechanica ; Volume 233, Issue 5 , 2022 , Pages 1881-1894 ; 00015970 (ISSN) ; Dizani, M ; Shamloo, A ; Sharif University of Technology
Springer
2022
Abstract
Cell separation microfluidic devices have evolved into a multitude of biomedical and clinical research. Nonetheless, many critical issues remain in the way of achieving an excellent separation of target cells from a heterogeneous sample. Parallel to the abundant experimental studies related to the hybrid microfluidic methods, it is easy to perceive the lack of numerical investigations in order to optimize the separation process and its accuracy. In this study, for the first time to the best of our knowledge, a hybrid system by integrating acoustophoresis and pinched-flow fractionation (PFF) is proposed to achieve a viable system for a wide-range, precise separation. Employing the ultrasound...
A plasmonic gold nanofilm-based microfluidic chip for rapid and inexpensive droplet-based photonic PCR
, Article Scientific Reports ; Volume 11, Issue 1 , December , 2021 ; 20452322 (ISSN) ; Bagheri, M ; Shamloo, A ; Kazemipour Ashkezari, A. H ; Sharif University of Technology
Nature Research
2021
Abstract
Polymerase chain reaction (PCR) is a powerful tool for nucleic acid amplification and quantification. However, long thermocycling time is a major limitation of the commercial PCR devices in the point-of-care (POC). Herein, we have developed a rapid droplet-based photonic PCR (dpPCR) system, including a gold (Au) nanofilm-based microfluidic chip and a plasmonic photothermal cycler. The chip is fabricated by adding mineral oil to uncured polydimethylsiloxane (PDMS) to suppress droplet evaporation in PDMS microfluidic chips during PCR thermocycling. A PDMS to gold bonding technique using a double-sided adhesive tape is applied to enhance the bonding strength between the oil-added PDMS and the...
Photocatalytic degradation of vancomycin using titanium dioxide and optimization by central composite design
, Article International Journal of Environmental Science and Technology ; Volume 19, Issue 9 , 2022 , Pages 8957-8968 ; 17351472 (ISSN) ; Yousefinejad, S ; Dehghani, M ; Borghei, S. M ; Javid, A. H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Conventional wastewater treatment processes are not completely effective in removing vancomycin. In this study, affecting parameters on vancomycin degradation, such as pH, catalyst, initial vancomycin concentration, temperature, and reaction time were investigated simultaneously during a removal process based on titanium dioxide with ultraviolet irradiation in an aqueous solution. Titanium dioxide was synthesized and characterized using X-ray diffraction and scanning electron microscopy. The average size of the synthesized crystals was 4.7 (± 0.2) nm. Design of experiments was done by a central composite design based on the response surface methodology and multiple linear regression was...
Vancomycin removal using TiO2–clinoptilolite/UV in aqueous media and optimisation using response surface methodology
, Article International Journal of Environmental Analytical Chemistry ; 2022 ; 03067319 (ISSN) ; Yousefinejad, S ; Dehghani, M ; Borghei, S. M ; Javid, A. H ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Investigations have shown the traces of antibiotics in surface water, groundwater, wastewater treatment plants, and drinking water. However, conventional wastewater treatment is not entirely effective for vancomycin degradation. Advanced oxidation is one of the most widespread methods of antibiotic degradation in aqueous media. Vancomycin was quantified by high-performance liquid chromatography. The Response Surface Methodology (RSM) based on Central Composite Design (CCD) was used to explore and optimise the effect of the independent variables on vancomycin degradation. Independent variables were as follows: pH (3–11), vancomycin concentration (15–75 mg/L), TiO2–clinoptilolite (25–125 mg in...
Origin of Quantum Potential: Have the Presented Proposals Been Successful?
,
M.Sc. Thesis
Sharif University of Technology
;
Golshani, Mehdi
(Supervisor)
Abstract
At least nine different formalisms have been presented for Quantum mechanics which by itself can indicate the incomplete understanding of Quantum theory. Each formalism has its own ups and downs, but de Broglie–Bohm approach which is based on representing a causal interpretation has a special place among them. This approach not only can explain the statistical approach to an ensemble of systems, but also can describe single systems. There are two general approaches in de Broglie–Bohm formalism. The first approach which includes more things in itself than the other approach is Bohm’s which considers Quantum potential energy as the principal factor in causing Quantum effects. The original idea...
Flexural instability of viscoelastic spinning cylinders partially filled with liquid
, Article International Journal of Structural Stability and Dynamics ; Volume 9, Issue 1 , 2009 , Pages 45-60 ; 02194554 (ISSN) ; Haddadpour, H ; Sharif University of Technology
2009
Abstract
This paper deals with the determination of free vibration characteristics and instability conditions of flexible spinning cylinders partially filled with fluid. Using the linearized Navier-Stokes equations for the incompressible, inviscid flow, a 2D model is developed for fluid motion at each section of the cylinder. The forces exerted on the cylinder wall as a result of the fluid motion are calculated as functions of lateral acceleration of the cylinder axis in the Laplace domain. Applying the Hamilton principle, the governing equations of flexural motion of the cylinder are derived and then combined with the equations describing the fluid forces to obtain the coupled field equations of the...
An analytic approach used to design a low power and low phase noise CMOS LC oscillator
, Article 2004 IEEE International Frequency Control Symposium and Exposition. A Conference of the IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society (UFFC-S), Montreal, 23 August 2004 through 27 August 2004 ; 2005 , Pages 432-435 ; Behroozi, H ; Yuhas M.P ; Sharif University of Technology
2005
Abstract
An analytic method to predict the oscillation amplitude and supply current values of a differential CMOS LC oscillator is discussed. The phase noise performance for this kind of oscillator is predicted by using a simplified model. This method enables us to design an optimized oscillator in terms of minimum phase noise and power consumption. The validity of the presented method is demonstrated by designing an LC CMOS oscillator in a 0.24μm CMOS technology. The predictions obtained from the derived expressions are in good agreement with simulation results over a wide range of the supply voltage. © 2004 IEEE
δ M formalism: a new approach to cosmological perturbation theory in anisotropic inflation
, Article Journal of Cosmology and Astroparticle Physics ; Volume 2018, Issue 3 , 2018 ; 14757516 (ISSN) ; Ahmadi, N ; Abolhasani, A. A ; Sharif University of Technology
Institute of Physics Publishing
2018
Abstract
We study the evolution of the metric perturbations in a Bianchi background in the long-wavelength limit. By applying the gradient expansion to the equations of motion we exhibit a generalized "Separate Universe" approach to the cosmological perturbation theory. Having found this consistent separate universe picture, we introduce the δ M formalism for calculating the evolution of the linear tensor perturbations in anisotropic inflation models in almost the same way that the so-called δ N formula is applied to the super-horizon dynamics of the curvature perturbations. Similar to her twin formula, δ N, this new method can substantially reduce the amount of calculations related to the evolution...
Extract Non-Line-of-Sight state of base stations and error mitigation technique for wireless localization in micro-cell networks
, Article Computer Communications ; Volume 35, Issue 7 , 2012 , Pages 885-893 ; 01403664 (ISSN) ; Golmohammadi, S ; Shadi, K ; Sharif University of Technology
2012
Abstract
Non Line of Sight (NLOS) propagation is a challenging issue which the performance of network based wireless localization is limited by errors primarily caused by NLOS corruption. NLOS is inherently a dominant source of errors in metropolitan area wireless networks, like cellular one, so in this paper we discuss our proposed algorithm within cellular network terminology. This paper contributes two novel algorithms. The first one is to extract the NLOS state of base station (BS) and the second one is a correction algorithm to enhance the measurements accuracy. Our proposed algorithm discuses a novel localization technique to estimate true mobile terminal (MT) location from a set of possibly...
Non-line-of-sight error mitigation technique for wireless localization in micro-cell networks
, Article 2011 4th IFIP International Conference on New Technologies, Mobility and Security, NTMS 2011 - Proceedings, 7 February 2011 through 10 February 2011, Paris ; 2011 ; 9781424487042 (ISBN) ; Shadi, K ; Golmohammadi, S ; Sharif University of Technology
2011
Abstract
Non Line of Sight (NLOS) propagation is a challenging issue which cause large errors in wireless localization systems. NLOS is especially a dominant source of errors in metropolitan area wireless networks like cellular ones. We discuss our algorithms within cellular network terminology. This paper contributes two novel algorithms. The first algorithm is to extract the NLOS state of base stations and the second one is a correction algorithm to enhance the measurements accuracy. Our introduced algorithms can easily operate with other wireless localization algorithms and reduced NLOS error. These algorithms are proposed for network-based localization because of the amount of calculation
Reduced order modeling of liquid sloshing in 3D tanks using boundary element method
, Article Engineering Analysis with Boundary Elements ; Volume 33, Issue 6 , 2009 , Pages 750-761 ; 09557997 (ISSN) ; Haddadpour, H ; Ghasemi, M ; Sharif University of Technology
2009
Abstract
This paper presents the application of reduced order modeling technique for investigation of liquid sloshing in three-dimensional tanks. The governing equations of sloshing are written using a boundary element formulation for incompressible potential flow. Then, the governing equations are reduced to a more efficient form that is represented only in terms of the velocity potential on the liquid free surface. This particular form is employed for eigen-analysis of fluid motion and the sloshing frequencies and mode shapes are determined. Then, the sloshing frequencies and the corresponding right- and left-eigenvectors are used along the modal analysis technique to find a reduced order model...
Effect of thermomechanical processing on forming limit diagrams predicted by neural networks
, Article Materials and Manufacturing Processes ; Volume 23, Issue 8 , 2008 , Pages 829-833 ; 10426914 (ISSN) ; Shafiei M, A ; Naeimi, H ; Sharif University of Technology
2008
Abstract
In the present work, an artificial neural network (ANN) model was developed for predicting the effect of thermo-mechanical processing on the forming limit diagram (FLD) of low carbon steels. The model introduced here considers the content of carbon, the hot finishing temperature, the degree of cold work, the work hardening exponent, the initial yield stress and the ASTM grain size as inputs; while, the predicted FLDs are presented as outputs. The results show that the predicted FLDs by the ANN model are very accurate exhibiting the maximum error of 9% over the whole strain region. The model predicted that with increasing the degree of cold rolling before annealing, the drawability is...
Nonlinear dynamics of extensible viscoelastic cantilevered pipes conveying pulsatile flow with an end nozzle
, Article International Journal of Non-Linear Mechanics ; Volume 91 , 2017 , Pages 22-35 ; 00207462 (ISSN) ; Haddadpour, H ; Dehghani Firouz Abadi, R ; Abtahi, H ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Nonlinear dynamics of an extensible cantilevered pipe conveying pulsating flow is considered in this paper. The fluid flow fluctuates harmonically and exhausts via a nozzle attached to the end of the pipe. Taking into account the extensibility assumption, the coupled nonlinear lateral–longitudinal equations of motion are derived using Hamilton's principle and discretized via Galerkin's method. The adaptive time step Adams algorithm is applied to extract the time response, and then the bifurcation, power spectral density and phase plane maps are plotted for some case studies. Effects of some geometrical parameters such as flow mass, pulsating flow frequency, gravity, nozzle mass and nozzle...
Analytical solution of an induced fiber grating relative humidity sensor
, Article Iranian Journal of Science and Technology, Transaction A: Science ; Volume 44, Issue 2 , 2020 , Pages 519-526 ; Rooholamininejad, H ; Bahrampour, A. R ; Sharif University of Technology
Springer
2020
Abstract
In our previous work, a distributed moisture sensor based on the induced long-period fiber grating in the presence of moisture is proposed. The proposed structure is analyzed numerically (Opt Laser Technol 117:126–133, 2019). In this article, due to the axial symmetry and periodic structure of the proposed sensor, the Love’s potential and Fourier series are employed to obtain an analytical solution for the refractive index variation along the sensor versus moisture density. The analytical method reduces the computation time relative to our numerical calculation drastically. The analytical results are in good agreement with those that are obtained by numerical calculations. The analytical...
Sloshing effects on supersonic flutter characteristics of a circular cylindrical shell partially filled with liquid
, Article International Journal for Numerical Methods in Engineering ; 2018 ; 00295981 (ISSN) ; Ovesy, H. R ; Dehghani Firouz Abadi, R ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
This paper aims to revisit the effect of sloshing on the flutter characteristics of a partially liquid-filled cylinder. A computational fluid-structure interaction model within the framework of the finite element method is developed to capture fluid-structure interactions arising from the sloshing of the internal fluid and the flexibility of its containing structure exposed to an external supersonic airflow. The internal liquid sloshing is represented by a more sophisticated model, referred to as the liquid sloshing model, and the shell structure is modeled by Sanders' shell theory. The aerodynamic pressure loading is approximated by the first-order piston theory. The initial geometric...
Hydroelastic analysis of two degree of freedom hydrofoil using a reduced-order hydrodynamic model considering unsteady partial sheet cavity flows
, Article Journal of Fluids and Structures ; Volume 81 , 2018 , Pages 116-130 ; 08899746 (ISSN) ; Haddadpour, H ; Dehghani Firouz Abadi, R ; Sharif University of Technology
Academic Press
2018
Abstract
In the present study a new, fast, precise algorithm for studying hydroelastic stability of a typical section with two degrees of freedom (2DOF) is proposed based on the finite element method (FEM), while the partial sheet cavitation effects are considered. For this means, the steady cavity boundary is calculated by some conventional iterative procedures, developed based on the potential flow simulation. Thereafter, assuming that the amplitude and the frequency of the body oscillations are altered so that the cavity length in unsteady flow remains unchanged, the simulation of the unsteady hydrodynamic flow is performed by imposing some velocity fluctuations over the rigid cavity boundary. For...
Producing ultrafine-grained aluminum rods by cyclic forward-backward extrusion: Study the microstructures and mechanical properties
, Article Materials Letters ; Volume 74 , May , 2012 , Pages 147-150 ; 0167577X (ISSN) ; Zaeem, M. A ; Dehghani, K ; Shivaee, H. A ; Sharif University of Technology
2012
Abstract
A cyclic forward-backward extrusion (CFBE) process was used as a severe plastic deformation (SPD) technique to produce ultrafine-grained aluminum rods. Yield strength and tensile strength of the specimens increased by increasing the number of CFBE cycles, while elongation to break decreased due to an increase in the grain refinement and microhardness. According to transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) results, the average grain size was reduced from 120 μm to 315 nm after only 3 cycles of CFBE