Loading...
Search for:
chizari--mahmoud
0.08 seconds
Total 651 records
Experimental Study of the Effect of Bone Density on the Fixation Strength of Graft by Bashti Bone Plug Technique (BBPT) and Comparison with the RCI Interference Screws in Anterior Cruciate Ligament Reconstruction
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor) ; Chizari, Mahmoud (Supervisor)
Abstract
Bashti Bone Plug Technique (BBPT) is an implant-less method which can be used in an Anterior Cruciate Ligament (ACL) reconstructive surgery. The technique uses a core bone plug to fix the tendon graft into the bone tunnel. This study investigates the effect of the core bone density on fixation strength in BBPT method. A series of experimental test has been performed to examine the hypothesis of the study. Thirty fresh bovine digital extensor tendon used in three different groups. Sawbones blocks with densities of 160, 240 and 320 kg/m^3 used in substitute of the bone to model the effect of density on the strength of the fixation. The core bone plugs and tunnels created using a custom made...
Designing and Manufacturing of an Electrospinning Machine and Prediction of Mechanical Responses of Artificial Blood Vessels Using Neural Networks and Finite Element Analysis
, M.Sc. Thesis Sharif University of Technology ; Nourani, Amir (Supervisor) ; Chizari, Mahmoud (Co-Supervisor)
Abstract
Cardiovascular disease is one of the most leading causes of death in the world and one of the common methods for treating such diseases is replacing damaged blood vessels with artificial ones. Electrospinning, which is a method of producing polymer fibers, is one of the best and common methods of producing synthetic vessels. The first goal in this study was to create a suitable structure for fiber production; therefore, first, an electrospinning device and environmental chamber were designed and built. Then, the effect of alternative and uniform flow on the diameter and structure of the fibers was investigated using 15% wt. Polycaprolactone solution. The results of this study showed that the...
Effect of Geometry on the Fixation Strength of Anterior Cruciate Ligament Reconstruction Using BASHTI Technique
, M.Sc. Thesis Sharif University of Technology ; Nourani, Amir (Supervisor) ; Chizari, Mahmoud (Co-Supervisor)
Abstract
BASHTI is a new implant-less ACL reconstruction surgery which has recently been considered for its advantages. This study aimed to investigate the effects of tendon and cannulated drill bit diameter on the BASHTI fixation strength and core bone engaged length (CBEL) in an anterior cruciate ligament (ACL) reconstruction. It is believed that CBEL may affect both bone healing process and fixation strength in this technique. Bovine digital tendons and Sawbones blocks were used to mimic the ACL reconstruction. Tendons were sized to 6, 7, 8, 9, and 10 mm and the hole size for the 6-9 mm tendons was set to 10 mm while for the 10 mm tendon was set to 12 mm. Mechanical strength of the specimens was...
Effects of Using Sheath on Fixation Strength of Bashti Bone Plug Technique (BBPT) in an Anterior Cruciate Ligament (ACL) Reconstruction
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor) ; Chizari, Mahmoud (Supervisor)
Abstract
Bashti Bone Plug Technique (BBPT) is a novel implant-less surgical methodology for Anterior Cruciate Ligament (ACL) reconstruction. The technique uses the core bone plug belonging to the patient, cut during tunneling with hole saw drill bit, to fix the ends of the tendon graft. Results show that when fitting the bone plug in this method, a large strike is required for fixation which leads to breaking the bone plug and consequently reducing the effective length of the bone plug inside the tunnel during fixation. Therefore, it was decided to use the sheath which covers the bone plug to overcome said challenges since during fixation with the sheath, Due to the low friction coefficient in these...
Reliability of Ultrasonic Technique Used for Defect Detection of Spot Welded Plates in Automotive Industry
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossien (Supervisor) ; Chizari, Mahmoud (Supervisor) ; kashizadeh, Kazem Reza (Co-Supervisor)
Abstract
Resistance Spot Welding (RSW) is one of the common techniques for connecting steel sheets in automotive industries. There are about 3000-5000 RSWs in the automotive chassis and body. Therefore, health and quality of RSW play a critical role in the final product performance. Also, welding process should be performed in a fully controlled program to ensure the durability of the vehicle body. In the automotive industry, there are various non-destructive methods (i.e., Chisel and Ultrasonic tests) and peel test as a destructive test (DT) to control the quality of RSW. Since the DT method is costly (waste of time, manpower, and materials), the main aim of the present research is to evaluate the...
Developing a Method for Fatigue Life Assessment of Vehicle Biw by Considering Spot Welding Connections
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor) ; Chizari, Mahmoud (Supervisor) ; Reza Kashyzadeh, Kazem (Co-Supervisor)
Abstract
One of the most important considerations in the vehicle design procedure is the durability of the components. Among different parts of a vehicle, the body is the main load-bearing component and as a result, its durability is critical. Due to the expensive and time-consuming nature of fatigue tests, finite element based durability analysis is of great interest among automotive industry. The aim of this research is to provide an algorithm for a more accurate and efficient durability analysis of the vehicle body by considering inertia effects. By using the multi-body dynamics model of the full vehicle and the finite element model of the vehicle body, the vehicle body structure is analyzed from...
Effect of cyclic loading on the temporomandibular joint
, Article Lecture Notes in Engineering and Computer Science ; Volume 1 , 2014 , Pages 655-658 ; ISSN: 20780958 ; ISBN: 9789881925275 ; Wang, B ; Chizari, M ; Sharif University of Technology
2014
Abstract
This research is aiming to investigate the mechanical behaviour of the temporomandibular joint (TMJ), in response to kinematics/cyclical loading caused through actions of speech and mastication. A set of in-vitro experimental tests has been performed in three different groups on a fresh sheep jaw bone to examine the hypothesis of the study. No failure was monitored during the cyclical test. The study was concluded that the amount of loading is effective on the displacement of the TMJ
Nano-plasmonic thin-film solar cell receiver in visible light communication
, Article 10th International Symposium on Communication Systems, Networks and Digital Signal Processing, 20 July 2016 through 23 July 2016 ; 2016 ; 9781509025268 (ISBN) ; Olyaee, S ; Chizari, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
We propose a nano-plasmonic thin-film solar cell (TFSC) as a receiver for the visible light communication (VLC). The presented design is a novel and optimized structure that can be used instead of photodetectors and power supplies in the VLC. The plasmonic TFSC that described in this work is capable of increasing the light absorption in comparison with the conventional thick Si solar cell without plasmonic nanostructures. However, plasmonic nanoparticles can improve the absorption of Si solar cell in a visible range of solar spectra. In this paper, different situations for inserting nanoparticles in an active layer are considered and the absorption is calculated as a function of particle...
Let me join two worlds! analyzing the integration of web and native technologies in hybrid mobile apps
, Article Proceedings - 17th IEEE International Conference on Trust, Security and Privacy in Computing and Communications and 12th IEEE International Conference on Big Data Science and Engineering, Trustcom/BigDataSE 2018, 31 July 2018 through 3 August 2018 ; 2018 , Pages 1814-1819 ; 9781538643877 (ISBN) ; Rezaiee, M ; Chizari, A ; Sharif University of Technology
2018
Abstract
We can notice that security problems of inappropriate integration of native and web technologies in hybrid mobile applications (apps) have been covered in the related state-of-the-art research. However, analyzing hybrid mobile apps' unique behaviors has been seldom addressed. In this paper, we explore the influence of native and web technologies integration in hybrid mobile apps on the generated profile of mobile applications. Specifically, we analyze the type of Security Sensitive APIs (SS-APIs) exposed to web content and identify the corresponding usage patterns by systematically tracking function-call-graphs of a large number of hybrid and native mobile apps. Our investigations indicate...
A multi-objective approach to optimize the weight and stress of the locking plates using finite element modeling
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 236, Issue 2 , 2022 , Pages 188-198 ; 09544119 (ISSN) ; Nourani, A ; Chizari, M ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
This paper aims to identify an optimum bone fracture stabilizer. For this purpose, three design variables including the ratio of the screw diameter to the plate width at three levels, the ratio of the plate thickness to the plate width at three levels, and the diameter of the bone at two levels were selected for analysis. Eighteen 3D verified finite element models were developed to examine the effects of these parameters on the weight, maximum displacement and maximum von Mises stress of the fixation structure. Considering the relations between the inputs and outputs using multivariate regression, a genetic algorithm was used to find the optimal choices. Results showed that the diameter of...
Sheathed fixation improves BASHTI technique in an anterior cruciate ligament reconstruction
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 237, Issue 3 , 2023 , Pages 375-384 ; 09544119 (ISSN) ; Farrahi, G ; Chizari, M ; Sharif University of Technology
SAGE Publications Ltd
2023
Abstract
Bone and Site Hold Tendon Inside (BASHTI) technique is an implant-less surgical methodology used for anterior cruciate ligament (ACL) reconstruction. It has some clinical advantages, such as speeding up the healing process. Since the force required to insert the core bone inside the tunnel may damage the core bone and affect the fixation process, the study aims to investigate the strength of fixation of BASHTI technique using proposed sheathed core bones. Experimental tests were performed to evaluate the biomechanical strength of the fixation. Synthetic bone combined with bovine tendons as a graft was used. Polymers were used to create the sheath for mechanical testing. The results showed...
Optical and Electrical Properties of Nanostructures Prepared by Hydrothermal Method for Application in Nanostructured Solar Cell Electrode
, M.Sc. Thesis Sharif University of Technology ; Iraji Zad, Azam (Supervisor)
Abstract
In this research we focus on study and fabrication of one dimentianal TiO2 nanostructures and nanoheterostructures on TiO2 nanofibers in order to use them in Dye Sensitized Solar Cells (DSC). Nanofibers of titanium oxide have been fabricated using hydrothermal method. Then, hierarchical TiO2 nanostructures were grown on the nanofibers via another hydrothermal step. Increasing the effective surface of nanofibers, we achieved two secondary architectures from fibers:1-Nanoparticular fibers (TiO2 nanoparticles grown on nanofibers).2-Nanostars.After fabrication, the SEM and XRD characterizations were provided. Furthermore, the suitable pastes of these nanostructures were prepared for application...
Two quasi orthogonal space-time block codes with better performance and low complexity decoder
, Article 10th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2016, 20 July 2016 through 23 July 2016 ; 2016 ; 9781509025268 (ISBN) ; Talebi, S ; Chizari, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
This paper presents two new space time block codes (STBCs) with quasi orthogonal structure for an open loop multi-input single-output (MISO) systems. These two codes have been designed to transmit from three or four antennas at the transmitter and be given to one antenna at the receiver. In this paper first, the proposed codes are introduced and their structures are investigated. This is followed by the demonstration of how the decoder decodes half of transmitted symbols independent of the other half. The last part of this paper discusses the simulation results, makes performance comparison against other popular approaches and concludes that the proposed solutions offer superiority
Biomechanical aspects of the scapula-glenoid fixation in a reverse shoulder implant
, Article World Congress on Engineering 2016, WCE 2016, 29 June 2016 through 1 July 2016 ; Volume 2224 , 2016 , Pages 1205-1210 ; 20780958 (ISSN); 9789881404800 (ISBN) ; Muhandiram, J ; Abulkhair, N ; Chizari, M ; Sharif University of Technology
Newswood Limited
2016
Abstract
The reverse shoulder implant is an implant for total replacement of the glenohumeral joint of patients suffering from osteoarthritis and with a damaged rotator cuff. The problem that arises with these conjoined ailments is that the displacement of the humeral head causes limited movement of the upper limb, with vertical mobility restricted to only allow for the arm to ascend to roughly the height of the shoulder. Attaching the ball to the scapula and the socket to the top of the humerus fixes the centre of rotation of the joint to increase the moment arm over the healthy shoulder's original position enabling patients' movement and dexterity to return. In this study the numerical evaluation...
Square-hexagonal nanostructured photonic crystal fiber at 1550 nm wavelength
, Article 10th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2016, 20 July 2016 through 23 July 2016 ; 2016 ; 9781509025268 (ISBN) ; Nikoosohbat, A ; Mohebzadeh Bahabady, A ; Chizari, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Photonic crystal fibers (PCFs) are widely used in optical communications systems, nonlinear devices, gas sensors, high power transmission, and so on. Photonic crystal fiber with minimum values of confinement loss, nonlinear effects, and chromatic dispersion is used in optical communication. But in some applications, high nonlinear coefficient is required. This paper presents new design of index-guiding photonic crystal fiber (IGPCF) with characteristics appropriate for nonlinear applications. In the present design with a square-hexagonal nano-structure having air holes with unequal diameters, nearly zero dispersion at the wavelength range of 1540 to 1550 nm is achieved. The simulation...
Behaviour of columns made from high strength steel
, Article World Congress on Engineering 2016, WCE 2016, 29 June 2016 through 1 July 2016 ; Volume 2224 , 2016 , Pages 1184-1187 ; 20780958 (ISSN); 9789881404800 (ISBN) ; Kamalarajah, R ; Cashell, K. A ; Chizari, M ; Sharif University of Technology
Newswood Limited
2016
Abstract
The buckling behaviour of compression members is very important in structural engineering especially those that are made from high strength steel (HSS). This paper presents an investigation into the behaviour of four columns which were designed according to EN 1993-1-1 (2005) so that the buckling capacity of both HSS and mild steel column was equal. A finite element model was created which included imperfections due to residual stresses as well as local and global imperfections. It was found that the buckling capacity of the columns made from 460 MPa steel was lower than that for similar capacity mild steel columns with a yield strength of 275 MPa. Accordingly, a buckling curve for HSS is...
Broadband, polarization-insensitive, and wide-angle optical absorber based on fractal plasmonics
, Article IEEE Photonics Technology Letters ; Volume PP, Issue 99 , 2016 ; 10411135 (ISSN) ; Abdollahramezani, S ; Chizari, A ; Khavasi, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, a plasmonic absorber consisting of a metal-dielectric-metal stack with a top layer of Sierpinski nanocarpet is theoretically investigated. Such a compact absorber depicts broadband angle-independent behavior over a wide optical wavelength range (400 700 nm) and a broad range of incidence angles (0 80). Including several feature sizes, such a fractal-like structure shows average simulated extinction response of 0:85 for either transverse electric or magnetic polarization states under normal incidence. Underlying mechanisms of absorbance due to excited surface plasmon modes as well as electric/magnetic dipole resonances are well revealed by investigating electric field, magnetic...
Fabrication of phase-change core/shell nanofibers based on a eutectic fatty acid mixture to control body temperature fluctuations
, Article Materials Chemistry and Physics ; Volume 245 , 15 April , 2020 ; Heidarzadeh, N ; Chizari Fard, G ; Maleknia, L ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
A sustainable eutectic mixture of two fatty acids, i.e. Lauric acid (LA) and Palmitic acid (PA), was produced as Phase Change Materials (PCMs) to control body temperature fluctuations. Based on thermodynamic calculations and related experimental analyses, the mass ratio of the mixture was chosen as LA:PA = 69:31. A core-shell structure was prepared through coaxial electrospinning, so as to prevent the leakage of PCM during phase change from the solid state to liquid one. Nylon 6 covered the core as the shell of the prepared nanofiber. The optimized nanofibers were obtained with the diameter of 152.7 nm. The produced PCM possessed an onset melting temperature of 32.17 °C, which was close to...
A comprehensive review on design, monitoring, and failure in fixed offshore platforms
, Article Journal of Marine Science and Engineering ; Volume 9, Issue 12 , 2021 ; 20771312 (ISSN) ; Shaterabadi, M ; Kashyzadeh, K. R ; Chizari, M ; Sharif University of Technology
MDPI
2021
Abstract
Offshore platforms have had diverse applications in the marine industry, for example, oil or gas platforms can provide facilities to store the oil and gas before transport those to refineries. Offshore wind turbines are another well-known use of the offshore platform for generating power. As platforms encounter various strong forces from water and wind currents, the materials used for these structures are mainly steel or concrete. These platforms are classified into different types, according to the depth of water and their applications. In addition, offshore platforms, as artificial reefs may be used for decades at different marine conditions. Consequently, their design and maintenance are...
Trimming of sheep spinal cord by waterjet; an experimental study
, Article Heliyon ; Volume 9, Issue 7 , 2023 ; 24058440 (ISSN) ; Ahmadian, M. T ; Chizari, M ; Samimiardestani, H ; Sharif University of Technology
Elsevier Ltd
2023
Abstract
The spinal cord is a structure of nervous tissue that primarily transmits nerve signals from the motor cortex to the body and from the afferent fibers of the sensory neurons to the sensory cortex. It is enveloped by three layers of meninges. Covering provides a supportive framework for the cerebral and cranial vasculature and protects the central nervous system (CNS) from mechanical damage. Surgical operation in the vicinity of the spinal cord is complicated and risky because it exposes it to probably irreversible damage. To reduce the risk of these operations, attempts have been made to remove the tumor using safer methods like waterjet operation. In these methods, the waterjet and spinal...