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diagnostics
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Design and Prototype of a Diagnostic Laparoscopic Instrument Capable of Measuring Characteristics of Living Tissues During Surgery
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor)
Abstract
in laparoscopic surgeries, act zone tissues are not directly palpable for the surgeon. Therefore, evaluating the mechanical behavior of the tissue and distinguishing healthiness or illness of that, are not achievable for the surgeon. In this treatise, the matter of discerning the soft and bulky tissues mechanical properties by a robotic arm during the laparoscopic surgery, is regarded. In first step, a tool like a two finger miniature hand was designed in which either of fingers have utilized a parallelogram mechanism for opening and closing. The dimensional design of the mechanism was undertake in away that the tool has the ability of going through a 10mm diameter path and grabbling and...
Estimation of Genetically Significant Dose to the Iranian Population from Diagnostic Radiology Procedures
, M.Sc. Thesis Sharif University of Technology ; Sohrabpour, Mostafa (Supervisor) ; Sharifzadeh, Monireh (Co-Advisor)
Abstract
Genetic significant dose to the Iranian population from diagnostic radiology procedures has been measured. A survey of 26500 radiology patients has radiological tests, age and sex distribution. A second survey has produced the radiological operational parameters, including kV, mAs, FTD, field size, filtration, film number & body orientation. Statistical demographic data have been obtained and from which child expectancy number have been calculated. A Rando phantom has been used for dosimetry phase of the gonad doses using TLD. Combining all of the above data a new GSD of 10.5 mrem/year has been calculated which is 14% higher than the previous number measured in 1980
Design and Implementation of an Intention-based Control System for a Lower Limb Exoskeleton by Combining Biological, Kinematic and Interaction Force Signals
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Gholamreza (Supervisor)
Abstract
The goal of this project is to propose an algorithm to detect human motion intent during level walking. The primary aim of this algorithm should be to reduce human-robot interaction forces by combining EMG and force signals. Human gait is composed of 6 different stages. During each stage, each muscle is activated differently so it is possible to detect human intent by a pattern recognition technique. However, due to the fact that EMG signals are unrepeatable and noisy, we propose that combining EMG, motion and interaction force signals may lead to more concise and repeatable estimates of human motion intent. As a result, this control approach is expected to reduce human robot interaction...
Improving Design of a Cross-Flow Turbine Based on Manufacturing and Testing The Prototype Turbine
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
Electric power is considered as one of the prerequisites of development in many countries. In recent years distributed electric power generation has attracted much attention. Small hydro potentials are considered as the most economical method of harvesting renewable energy and a suitable solution for earning income.In the last two years, a project was defined for Sharif University of Technology by Iran hydro-power authorities with the goal of spotting hydro potentials and design, manufacture and installation of three types of micro hydro powerplants for the first time in Iran. One of these powerplants use a micro Cross-Flow turbine. Although the prototype manufactured for this project is a...
Numerical Modeling of Diagnostic Fracture Injection Test
, M.Sc. Thesis Sharif University of Technology ; Shad, Saeed (Supervisor) ; Zivar, Davood (Co-Supervisor)
Abstract
Diagnostic Fracture Injection Test (DFIT) uses to identify the characteristics of the reservoir, including minimum horizontal stress, permeability, initial reservoir pressure, etc. The general steps of this process include fluid injection, fracture initiation in the matrix, fracture propagation and its closure due to fluid leak-off. The results of DFIT are analyzed in two stages based on the fracture closure event. The objective of this study is to investigate the effect of leak-off mechanisms on pressure-dependent leak-off (PDL), tip extension and fracture storage. To do so, different methods are used for identifying the cooperating parameters at each step. In order to analyze DFIT, a...
Experimental Investigation on Flame Chemiluminescence Emissions
, M.Sc. Thesis Sharif University of Technology ; Kebriaee, Azadeh (Supervisor)
Abstract
The Chemiluminescence method is considered as one of the most widely optical methods that used for identifying combustion systems. In this study, the OH^* and CH^* Chemiluminescence signals were measured with the use of PMT detector and other optical equipments for a bunsen burner. Also the effect of equivalence ratio and flow rate on these signals have been investigated. The results show that with increasing flow rate, OH^* and CH^* signals increase linearly. By changing the equivalence ratio, both signals were maximized near stoichiometric condition (OH^* in lean side and CH^* in the rich side). Therefore, both OH^* and CH^* are considered as indicators of released heat rate. It was also...
Electron trajectory evaluation in laser-plasma interaction for effective output beam
, Article Chinese Physics B ; Volume 19, Issue 6 , 2010 ; 16741056 (ISSN) ; Sadighi Bonabi, R ; Afarideh, H ; Sharif University of Technology
2010
Abstract
Using the ellipsoidal cavity model, the quasi-monoenergetic electron output beam in laser-plasma interaction is described. By the cavity regime the quality of electron beam is improved in comparison with those generated from other methods such as periodic plasma wave field, spheroidal cavity regime and plasma channel guided acceleration. Trajectory of electron motion is described as hyperbolic, parabolic or elliptic paths. We find that the self-generated electron bunch has a smaller energy width and more effective gain in energy spectrum. Initial condition for the ellipsoidal cavity is determined by laser-plasma parameters. The electron trajectory is influenced by its position, energy and...
Formation mechanism of bead-chain-like ZnO nanostructures from oriented attachment of Zn/ZnO nanocomposites prepared via DC arc discharge in liquid
, Article Materials Science in Semiconductor Processing ; Volume 72 , 2017 , Pages 128-133 ; 13698001 (ISSN) ; Poursalehi, R ; Naseri, N ; Sharif University of Technology
Abstract
Bead-chain-like ZnO nanoparticles (NPs) formed in colloidal solution from oriented attachment (OA) of spherical nanoparticles. Arc discharge in liquid is a cost-effective method for quick mass production of nanostructured materials without considerable environmental footprints. Applying voltage across two zinc rods as electrodes, which were immersed in water cause explosion of electrodes and plasma generation. Zn/ZnO nanocomposites produced by interaction of different active species in high-pressure and high-temperature plasma at the solid-liquid interface. Different sized nanoparticles with diameters of 26, 35, 40 and 60 nm at applied discharge currents of 150, 100, 50 and 20 A...
Highly sensitive selective sensing of nickel ions using repeatable fluorescence quenching-emerging of the CdTe quantum dots
, Article Materials Research Bulletin ; Volume 95 , 2017 , Pages 532-538 ; 00255408 (ISSN) ; Ghalkhani, M ; Akhavan, O ; Taghavinia, N ; Marandi, M ; Sharif University of Technology
Abstract
Highly sensitive nickel sensor based on repeatable fluorescence quenching-emerging mechanism was developed. Highly luminescent thioglycolic acid capped CdTe nanocrystals in aqueous solution were applied as the fluorescence probe. These nanocrystals represented a considerable photoluminescence quantum yield as high as 61%. The florescence was quenched by addition of Ni ions to the CdTe nanocrystals solution. Then it was recovered by injection of the proper amount of dimethylglyoxime as the releasing reagent. The relative fluorescence intensity (F0/F) was linearly proportional to the concentration of nickel ions in the range of 0.01–10 μM, with detection limit as low as 7 nM. Described method...
A hybrid fuzzy based algorithm for 3D human airway segmentation
, Article 2nd International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2008, Shanghai, 16 May 2008 through 18 May 2008 ; 2008 , Pages 2295-2298 ; 9781424417483 (ISBN) ; Ahmadian, A ; Sahba, N ; Tavakoli, V ; Alirezaie, J ; Fatemizadeh, E ; Rezaie, N ; Sharif University of Technology
IEEE Computer Society
2008
Abstract
Segmentation of the human airway tree from volumetric computed tomography images is an important stage for many clinical applications such as virtual bronchoscopy. The main challenges of previously developed methods are to deal with two problems namely, leaking into the surrounding lung parenchyma during segmentation and the need to manually adjust the parameters. To overcome these problems, a multi-seeded fuzzy based region growing approach in conjuction with the spatial information of voxels is proposed. Comparison with a commonly used region growing segmentation algorithm shows that the proposed method retrieves more accurate results by achieving the specificity and sensitivity of 98.81%...
Aortic dissection is determined by specific shape and hemodynamic interactions
, Article Annals of Biomedical Engineering ; Volume 50, Issue 12 , 2022 , Pages 1771-1786 ; 00906964 (ISSN) ; Marlevi, D ; Bruse, J. L ; Nezami, F. R ; Moradi, H ; Fortunato, R. N ; Maiti, S ; Billaud, M ; Edelman, E. R ; Gleason, T. G ; Sharif University of Technology
Springer
2022
Abstract
The aim of this study was to determine whether specific three-dimensional aortic shape features, extracted via statistical shape analysis (SSA), correlate with the development of thoracic ascending aortic dissection (TAAD) risk and associated aortic hemodynamics. Thirty-one patients followed prospectively with ascending thoracic aortic aneurysm (ATAA), who either did (12 patients) or did not (19 patients) develop TAAD, were included in the study, with aortic arch geometries extracted from computed tomographic angiography (CTA) imaging. Arch geometries were analyzed with SSA, and unsupervised and supervised (linked to dissection outcome) shape features were extracted with principal component...
A mixture of vortex terahertz radiation generation in inhomogeneous plasma by considering pump depletion
, Article Laser Physics ; Volume 29, Issue 1 , 2019 ; 1054660X (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
An attempt to extend helical terahertz radiation generation based on pump depletion is presented here. By considering an upward plasma density ramp, such a reasonable extension is examined to improve the results. It is claimed that the output terahertz energy is saturated which is attributed to laser pump divergence. The saturation effect is enhanced by considering suitable laser and plasma parameters. The adjustable slope of the density ramp is an important parameter for tuning terahertz generation effciency, which is restricted to the up and down limit. For the resonant excitation of terahertz radiation, the ripple wave number is suitably chosen to satisfy the phase matching condition....
A mixture of vortex terahertz radiation generation in inhomogeneous plasma by considering pump depletion
, Article Laser Physics ; Volume 29, Issue 1 , 2019 ; 1054660X (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
An attempt to extend helical terahertz radiation generation based on pump depletion is presented here. By considering an upward plasma density ramp, such a reasonable extension is examined to improve the results. It is claimed that the output terahertz energy is saturated which is attributed to laser pump divergence. The saturation effect is enhanced by considering suitable laser and plasma parameters. The adjustable slope of the density ramp is an important parameter for tuning terahertz generation effciency, which is restricted to the up and down limit. For the resonant excitation of terahertz radiation, the ripple wave number is suitably chosen to satisfy the phase matching condition....
Facile one-pot synthesis of polytypic (wurtzite–chalcopyrite) CuGaS2
, Article Applied Physics A: Materials Science and Processing ; Volume 122, Issue 3 , 2016 , Pages 1-10 ; 09478396 (ISSN) ; Mirkazemi, S. M ; Tahir, M. N ; Iraji Zad, A ; Ghasemzadeh, R ; Tremel, W ; Sharif University of Technology
Springer Verlag
2016
Abstract
Abstract: In this investigation, monodisperse CuGaS2 nanoparticles intended for use as visible-light-absorbing materials were synthesized using a facile one-step heating method that involved dissolving the precursors copper chloride, gallium acetylacetonate, and thiourea in a solvent consisting of either oleylamine alone or a combination of oleylamine, oleic acid, and 1-octadecene. The shapes of the resulting nanoparticles were either elongated, polygonal, or a mixture of both, depending on whether the crystal structure of the nanoparticles was predominantly wurtzite, predominantly chalcopyrite, or a more balanced mixture of both wurtzite and chalcopyrite (i.e., the nanoparticles were...
Optical radiomic signatures derived from optical coherence tomography images improve identification of melanoma
, Article Cancer Research ; Volume 79, Issue 8 , 2019 , Pages 2021-2030 ; 00085472 (ISSN) ; Fatemizadeh, E ; Blumetti, T ; Daveluy, S ; Moraes, A. F ; Chen, W ; Mehregan, D ; Andersen, P. E ; Nasiriavanaki, M ; Sharif University of Technology
American Association for Cancer Research Inc
2019
Abstract
The current gold standard for clinical diagnosis of melanoma is excisional biopsy and histopathologic analysis. Approximately 15–30 benign lesions are biopsied to diagnose each melanoma. In addition, biopsies are invasive and result in pain, anxiety, scarring, and disfigurement of patients, which can add additional burden to the health care system. Among several imaging techniques developed to enhance melanoma diagnosis, optical coherence tomography (OCT), with its high-resolution and intermediate penetration depth, can potentially provide required diagnostic information noninvasively. Here, we present an image analysis algorithm, "optical properties extraction (OPE)," which improves the...
An implementation of a CBIR system based on SVM learning scheme
, Article Journal of Medical Engineering and Technology ; Volume 37, Issue 1 , 2013 , Pages 43-47 ; 03091902 (ISSN) ; Fatemizadeh, E ; Badie, K ; Sharif University of Technology
2013
Abstract
Content-based image retrieval (CBIR) has been one of the most active areas of research. The retrieval principle of CBIR systems is based on visual features such as colour, texture and shape or the semantic meaning of the images. A CBIR system can be used to locate medical images in large databases. This paper presents a CBIR system for retrieving digital human brain magnetic resonance images (MRI) based on textural features and the support vector machine (SVM) learning method. This system can retrieve similar images from the database in two groups: normal and tumoural. This research uses the knowledge of the CBIR approach to the application of medical decision support and discrimination...
Hot electron generation enhancement by long duration positive chirped laser pulses
, Article Physica Scripta ; Volume 93, Issue 10 , 2018 ; 00318949 (ISSN) ; Sadighi Bonabi, R ; Sharif University of Technology
Abstract
Interaction of the chirped circularly polarized laser pulse with ramped density plasma is presented by particle-in-cell simulation. The obtained results indicate that the laser penetration depth into the plasma target and hot-electron generation can be improved by chirped induced transparency (CIT). Positive chirped pulses penetrate more deeply in the plasma leading to the hot electron enhancement and improvement of the maximum separation accelerating fields at the rear side of the target. For laser pulse with 150 fs time duration, there is 40% increase in the laser penetration depth in the target and the maximum amount of the electrostatic field is improved by a factor of 5 in the present...
Improvement of laser-driven proton beam quality by optimized intense chirped laser pulses
, Article Physics of Plasmas ; Volume 25, Issue 1 , 2018 ; 1070664X (ISSN) ; Amrollahi, R ; Sadighi Bonabi, R ; Sharif University of Technology
American Institute of Physics Inc
2018
Abstract
The effect of pulse shaping on the intense laser-driven proton beam produced through radiation pressure acceleration as a highly efficient mechanism is investigated. In this regard, the interaction of pulses with modified frequencies, including positive and negative chirped pulses with plasma, is simulated using particle-in-cell code. The simulation results indicate that the proton acceleration could be significantly enhanced for both negative and positive chirped pulses. As a consequence of the acceleration time extension as well as the electron heating suppression, a sharper and narrower proton beam could be achieved for negative chirped pulses. The same trend is observed for all negative...
Diagnosing anterior cruciate ligament injuries using a knee arthrometer: Design, fabrication, and clinical evaluation
, Article Biomedical Engineering - Applications, Basis and Communications ; Volume 23, Issue 3 , April , 2011 , Pages 181-192 ; 10162372 (ISSN) ; Sahraei, E ; Shirin, M. B ; Farahmand, F ; Tahmasebi, M. N ; Parnianpour, M ; Sharif University of Technology
2011
Abstract
Every year many people suffer from knee injuries. Previous studies on patients with knee injuries have shown that about 40% of knee injuries are Ligament injuries, and about 50% of the ligament injuries are the Anterior Cruciate Ligament (ACL) injuries. Along with other methods, knee arthrometers are widely used to diagnose ACL injuries. In the current research, a knee arthrometer was designed and developed to provide a reliable and repeatable measurement of knee laxity under anteriorposterior applied loads. Testretest configurations to examine repeatability of the device resulted in less than 1.5-mm difference for more than 97% of tests under applied loads of up to 90 N. These tests...
Hippocampal shape analysis in the Laplace Beltrami feature space for temporal lobe epilepsy diagnosis and lateralization
, Article Proceedings - International Symposium on Biomedical Imaging ; 2012 , Pages 150-153 ; 19457928 (ISSN) ; 9781457718588 (ISBN) ; Gandomkar, Z ; Soltaman Zadeh, H ; Moghadasi, S. R ; Sharif University of Technology
IEEE
2012
Abstract
Shape analysis plays an important role in many medical imaging studies. One of the recent shape analysis methods uses the Laplace Beltrami operator which is also used in this paper for hippocampal shape comparison. We proposed a feature vector which consists of size measures and shape descriptors based on Laplace Beltrami eigenvalues and eigenfunctions. The aforementioned feature space is utilised for automatic differentiating normal subjects from epileptic patients as well as distinguishing epileptic patients with left temporal lobe epilepsy (LTLE) from patients with right temporal lobe epilepsy (RTLE). Achieved results are diagnostic accuracy of 93% with 95% sensitivity and lateralization...