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Arbitrary Lagrangian-Eulerian unstructured finite-volume lattice-Boltzmann method for computing two-dimensional compressible inviscid flows over moving bodies
, Article Physical Review E ; Volume 101, Issue 2 , 2020 ; Hashemi Nasab, H ; Azampour, M. H ; Sharif University of Technology
American Physical Society
2020
Abstract
The objective of this study is to develop and apply an arbitrary Lagrangian-Eulerian unstructured finite-volume lattice-Boltzmann method (ALE-FVLBM) for solving two-dimensional compressible inviscid flows around moving bodies. The two-dimensional compressible form of the LB equation is considered and the resulting LB equation is formulated in the ALE framework on an unstructured body-fitted mesh to correctly model the body shape and properly incorporate the mesh movement due to the body motion. The spatial discretization of the resulting system of equations is performed by a second-order cell-centered finite-volume method on arbitrary quadrilateral meshes and an implicit dual-time stepping...
Application of arbitrary Lagrangian–Eulerian unstructured finite volume lattice Boltzmann method to simulate compressible viscous flows over moving bodies
, Article Meccanica ; Volume 58, Issue 12 , 2023 , Pages 2329-2346 ; 00256455 (ISSN) ; Hejranfar, K ; Azampour, M. H ; Sharif University of Technology
Springer Science and Business Media B.V
2023
Abstract
In this work, a central difference unstructured finite volume lattice Boltzmann method (FVLBM) in an arbitrary Lagrangian–Eulerian (ALE) framework is applied to effectively simulate the compressible viscous flows over moving bodies. Here, the two-dimensional compressible LB equation based on the multispeed Watari model is formulated in the ALE framework on an unstructured body-fitted mesh and the resulting equation is discretized by using the cell-centered finite volume method in which a central averaging scheme is made to calculate the numerical fluxes. A suitable dissipation term is added to the formulation to ensure the stability of the numerical scheme applied. The time integration is...
Analyzing Fluid–Structure Interaction Problems in Compressible Flows
, Ph.D. Dissertation Sharif University of Technology ; Hejranfar, Kazem (Supervisor)
Abstract
The goal of this thesis is the development and application of the finite volume method (FVM) with a same solution procedure in the fluid and structure domains for the simulation of fluid-structure interaction (FSI) problems in the compressible fluid flow. The unsteady Euler equations written in the arbitrary Lagrangian–Eulerian (ALE) form are considered as the governing equations of the compressible fluid flow and the moderate/large nonlinear deformation of the elastic structure is considered to be governed by the Cauchy equations in the Lagrangian/total Lagrangian forms. Therefore, the nonlinear phenomena in the unsteady compressible fluid flow and the large deformation of the elastic...
Self-supervised probe pose regression via optimized ultrasound representations for US-CT fusion
, Article Lecture Notes in Electrical Engineering ; Volume 1166 LNEE , 2024 , Pages 111-121 ; 18761100 (ISSN); 978-981971334-9 (ISBN) ; Velikova, Y ; Fatemizadeh, E ; Dakua, S. P ; Navab, N ; Sharif University of Technology
2024
Abstract
Aligning 2D ultrasound images with 3D CT scans of the liver holds significant clinical value in enhancing diagnostic precision, surgical planning, and treatment delivery. Conventional approaches primarily rely on optimization techniques, which often have a limited capture range and are susceptible to initialization errors. To address these limitations, we define the problem as “probe pose regression” and leverage deep learning for a more robust and efficient solution for liver US-CT registration without access to paired data. The proposed method is a three-part framework that combines ultrasound rendering, generative model and pose regression. In the first stage, we exploit a differentiable...
Image Matching Based on Manifold Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Fatemizadeh, Emad (Supervisor)
Abstract
Medical imaging is of interest because of information that will provide for doctors and registration is inevitable when we need to compare two or more images, taken from a subject at different times or with different sensors or when comparing two or more subjects together. Registration methods can be categorized in two major groups; methods based on feature and methods based on intensity. Methods in first group have three steps in common: feature extraction, finding matches and transform estimation. In second group it’s important to define a similarity measure and find the transform that minimizes this measure.
Manifold learning algorithms are mostly used as a dimensionality reduction...
Manifold learning algorithms are mostly used as a dimensionality reduction...
Multimodal Medical Image Registration using Deep Learning
, Ph.D. Dissertation Sharif University of Technology ; Fatemizadeh, Emadeddin (Supervisor)
Abstract
Medical imaging is a crucial part of modern healthcare, providing vital information for diagnosis, treatment, and monitoring of diseases. Physicians utilize various imaging modalities to obtain valuable information that aids in improving the treatment process. Ultrasound, due to its easy accessibility and lack of side effects, is one of the most commonly used modalities. Its alignment with 3D images such as CT scans and MRI provides useful information for treatment planning. Deep learning in image processing, including image alignment, has made significant advancements. One of the main challenges in this field is the lack of data for training deep networks, which becomes even more crucial in...
Diffusion as sound propagation: physics-inspired model for ultrasound image generation
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 15004 LNCS , 2024 , Pages 613-623 ; 03029743 (ISSN); 978-303172082-6 (ISBN) ; Velikova, Y ; Navab, N ; Azampour, M.F ; Sharif University of Technology
Springer
2024
Abstract
Deep learning (DL) methods typically require large datasets to effectively learn data distributions. However, in the medical field, data is often limited in quantity, and acquiring labeled data can be costly. To mitigate this data scarcity, data augmentation techniques are commonly employed. Among these techniques, generative models play a pivotal role in expanding datasets. However, when it comes to ultrasound (US) imaging, the authenticity of generated data often diminishes due to the oversight of ultrasound physics. We propose a novel approach to improve the quality of generated US images by introducing a physics-based diffusion model that is specifically designed for this image...
Visa-fss: a volume-informed self supervised approach for few-shot 3d segmentation
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 14221 LNCS , 2023 , Pages 112-122 ; 03029743 (ISSN); 978-303143894-3 (ISBN) ; Bitarafan, A ; Azampour, M. F ; Farshad, A ; Soleymani baghshah, M ; Navab, N ; Greenspan H ; Greenspan H ; Madabhushi A ; Mousavi P ; Salcudean S ; Duncan J ; Syeda-Mahmood T ; Taylor R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2023
Abstract
Few-shot segmentation (FSS) models have gained popularity in medical imaging analysis due to their ability to generalize well to unseen classes with only a small amount of annotated data. A key requirement for the success of FSS models is a diverse set of annotated classes as the base training tasks. This is a difficult condition to meet in the medical domain due to the lack of annotations, especially in volumetric images. To tackle this problem, self-supervised FSS methods for 3D images have been introduced. However, existing methods often ignore intra-volume information in 3D image segmentation, which can limit their performance. To address this issue, we propose a novel self-supervised...
Multitask Weakly Supervised Generative Network for MR-US Registration
, Article IEEE Transactions on Medical Imaging ; Volume 43, Issue 11 , 2024 , Pages 3780-3793 ; 02780062 (ISSN) ; Mach, K ; Fatemizadeh, E ; Demiray, B ; Westenfelder, K ; Steiger, K ; Eiber, M ; Wendler, T ; Kainz, B ; Navab, N ; Sharif University of Technology
2024
Abstract
Registering pre-operative modalities, such as magnetic resonance imaging or computed tomography, to ultrasound images is crucial for guiding clinicians during surgeries and biopsies. Recently, deep-learning approaches have been proposed to increase the speed and accuracy of this registration problem. However, all of these approaches need expensive supervision from the ultrasound domain. In this work, we propose a multitask generative framework that needs weak supervision only from the pre-operative imaging domain during training. To perform a deformable registration, the proposed framework translates a magnetic resonance image to the ultrasound domain while preserving the structural content....
Synthesis of quinazolin-4(3H)-one derivatives using heteropolyacids as heterogeneous and recyclable catalysts
, Article Asian Journal of Chemistry ; Volume 23, Issue 4 , 2011 , Pages 1588-1590 ; 09707077 (ISSN) ; Hashemi, M. M ; Heravi, M. M ; Bamoharram, F. F ; Sharif University of Technology
2011
Abstract
A highly efficient and simple procedure for the synthesis of quinazolin-4(3H)-ones from the condensation of 2-aminobenzamide with triethylorthoesters in presence of a catalytic amounts of heteropolyacids in various solvents is reported
Brain wave patterns in patients with chronic low back pain: a case-control study
, Article Basic and Clinical Neuroscience ; Volume 14, Issue 2 , 2023 , Pages 225-236 ; 22287442 (ISSN) ; Esfandiarpour, F ; Riahi, F ; Parnianpour, M ; Sharif University of Technology
Iran University of Medical Sciences
2023
Abstract
Introduction: Research evidence indicates that maladaptive reorganization of the brain plays a critical role in amplifying pain experiences and pain chronification; however, no clear evidence of change exists in brain wave activity among patients with chronic low back pain (CLBP). The objective of this study was to assess brain wave activity in patients with CLBP, compared to healthy controls. Methods: Twenty-five patients with CLBP and twenty-four healthy controls participated in the study. A quantitative electroencephalography device was used to assess brain wave activity in eyes-open and eyes-closed (EO and EC) conditions. The regional absolute and relative power of brain waves were...
Proposing a new model to approximate the elasticity modulus of granite rock samples based on laboratory tests results
, Article Bulletin of Engineering Geology and the Environment ; 2017 , Pages 1-10 ; 14359529 (ISSN) ; Esfandi Sarafraz, M ; Hasanipanah, M ; Mojtahedi, S. F. F ; Tahir, M. M ; Sharif University of Technology
2017
Abstract
An accurate examination of deformability of rock samples in response to any change in stresses is deeply dependent on the reliable determination of properties of the rock as analysis inputs. Although Young’s modulus (E) can provide valuable characteristics of the rock material deformation, the direct determination of E is considered a time-consuming and complicated analysis. The present study is aimed to introduce a new hybrid intelligent model to predict the E of granitic rock samples. Hence, a series of granitic block samples were collected from the face of a water transfer tunnel excavated in Malaysia and transferred to laboratory to conduct rock index tests for E prediction. Rock index...
Proposing a new model to approximate the elasticity modulus of granite rock samples based on laboratory tests results
, Article Bulletin of Engineering Geology and the Environment ; Volume 78, Issue 3 , 2019 , Pages 1527-1536 ; 14359529 (ISSN) ; Esfandi Sarafraz, M ; Hasanipanah, M ; Mojtahedi, S. F. F ; Tahir, M. M ; Sharif University of Technology
Springer Verlag
2019
Abstract
An accurate examination of deformability of rock samples in response to any change in stresses is deeply dependent on the reliable determination of properties of the rock as analysis inputs. Although Young’s modulus (E) can provide valuable characteristics of the rock material deformation, the direct determination of E is considered a time-consuming and complicated analysis. The present study is aimed to introduce a new hybrid intelligent model to predict the E of granitic rock samples. Hence, a series of granitic block samples were collected from the face of a water transfer tunnel excavated in Malaysia and transferred to laboratory to conduct rock index tests for E prediction. Rock index...
Investigation of the pyridinium ion transfer across the water/nitrobenzene interface by means of cyclic voltammetry and ac-impedance techniques
, Article Electrochimica Acta ; Volume 47, Issue 13-14 , 2002 , Pages 2209-2214 ; 00134686 (ISSN) ; Mahjani, M. G ; Jafarian, M ; Gobal, F ; Mousavi, M. F ; Shamsipur, M ; Sharif University of Technology
2002
Abstract
The transfer of pyridinium ion across the water/nitrobenzene interface has been studied by the methods of cyclic voltammetry and ac-impedance measurements. The diffusion coefficients of these species in both media, Dw,pyH+ = 4.4 × 10-5 and DNB,pyH+ = 2.16 × 10-5 cm2 s-1, as well as the diffusion coefficient of pyridine in the organic phase, DNB,py, 3.05 × 10-7 cm2 s-1, have been calculated. The standard potential of pyridinium ion transfer, and the corresponding free energy change and its distribution coefficient between the two phases, have been reported by means of cyclic voltammetry. Impedance measurements resulted in an arc in Nyquist diagrams representing the transfer of pyridinium ion...
Causes of common and frequent claims in oil, gas and petrochemical projects of Iran
, Article KSCE Journal of Civil Engineering ; Volume 18, Issue 5 , June , 2014 , Pages 1270-1278 ; ISSN: 12267988 ; Mortaheb, M. M ; Ahmadian, F. F. A ; Sharif University of Technology
2014
Abstract
Over recent years, frequent involvements in claims have been inevitable due to unpredictable economic changes and increasing complexities in construction industry. Therefore, even appropriately made contracts are not exempted from claims. On the other hand, construction contract claims are time-consuming, expense-involving and most likely leading to unsatisfactory results. However, there may be some positive outcomes, such as time extension or compensation of damages. To launch investigations, a list of important and frequent claims in oil and gas industry projects of Iran was extracted after a succinct documents review. Further, the most important claim causes were identified through...
On the largest eigenvalue of signed unicyclic graphs
, Article Linear Algebra and Its Applications ; Volume 581 , 2019 , Pages 145-162 ; 00243795 (ISSN) ; Belardo, F ; Heydari, F ; Maghasedi, M ; Souri, M ; Sharif University of Technology
Elsevier Inc
2019
Abstract
Signed graphs are graphs whose edges get signs ±1 and, as for unsigned graphs, they can be studied by means of graph matrices. Here we focus our attention to the largest eigenvalue, also known as the index of the adjacency matrix of signed graphs. Firstly we give some general results on the index variation when the corresponding signed graph is perturbed. Also, we determine signed graphs achieving the minimal or the maximal index in the class of unbalanced unicyclic graphs of order n≥3. © 2019
Design and analysis of a novel parallel mechanism for prosthetic knee wear test simulators
, Article Journal of Mechanical Science and Technology ; Volume 31, Issue 2 , 2017 , Pages 885-892 ; 1738494X (ISSN) ; Farahmand, F ; Durali, M ; Abedinnasab, M. H ; Sharif University of Technology
Korean Society of Mechanical Engineers
2017
Abstract
Using a parallel mechanism in the wear test simulators of prosthetic knees provides an easy access to the femoral and tibial components during tests. Moreover, because of its higher accuracy and load capacity, in comparison with serial mechanisms, it allows simulation of heavier tasks, such as climbing stairs, to be performed. This paper describes a new 3 Degree of freedom (DoF) spatial 2T1R (T: Translational DoF; R: Rotational DoF) parallel mechanism, for reproducing the force and motion of the tibial component of the knee prostheses in a wear test simulator. Kinematics and dynamics analysis of the mechanism indicated that it can satisfy the required DoFs, workspace and load capacity...
Fundamental mode fluxgate magnetometers for active magnetic shielding
, Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 ; ISSN : 21647054 ; 9789644634284 (ISBN) ; Eshraghi, M. J ; Forooghi, F ; Sarreshtedari, F ; Fardmanesh, M ; Sharif University of Technology
2011
Abstract
Fluxgate magnetometers with different design and core materials have been made. The sensors have been characterized and the frequency responses of the sensors have been measured. The fluxgate magnetometer based on orthogonal design and amorphous wire core working in fundamental mode reaches 30pT/Hz noise level and 40μV/nT sensitivity. Finally an active magnetic shield constructed based on the amorphous core fluxgate magnetometer reaches more than 60dB field attenuation for DC field and has a good response for frequencies below 100Hz
Electrocatalytic oxidation of methanol and glucose on NiCu alloy electrode
, Article Copper Alloys: Preparation, Properties and Applications ; 2011 , Pages 1-44 ; 9781612095042 (ISBN) ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2011
Abstract
Nickel-copper alloy modified glassy carbon electrodes (GC/NiCu) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol and glucose in alkaline solutions. The methods of cyclic voltammetery (CV), chronoamperometry (CA) and impedance spectroscopy (EIS) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution. In CV studies, in the presence of methanol NiCu alloy modified electrode shows a significantly higher response in oxidation reaction. The peak current of the...
Electrochemical impedance studies of methanol oxidation on GC/Ni and GC/NiCu electrode
, Article International Journal of Hydrogen Energy ; Volume 34, Issue 2 , 2009 , Pages 859-869 ; 03603199 (ISSN) ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2009
Abstract
The electro-oxidation of methanol on nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) in a 1 M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC/Ni corresponding to charge transfer resistance and adsorption of intermediates. Electro-oxidation of methanol on GC/NiCu shows negative resistance in impedance plots as signified by semi-circles terminating in the second quadrant. The impedance behavior shows different patterns at different applied anodic potential. The influence of the...