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Biomechanical Modeling of Human Eye in Car Airbag Blunt Impacts During Accident: an Empirical Test and Finite Element Study
, M.Sc. Thesis Sharif University of Technology ; Zohour, Hassan (Supervisor)
Abstract
Eye and vision are the most important tools and the perceptual sense of human. This important vital member is one of the most vulnerable organs of human body. For example in the United States 1.9 million eye surgery are being done yearly which include 9 thousand globe rupture and 30 thousand blindness due to impacts on the eye. Eye traumas could have occurred as mechanical, radiation, thermal, chemical, etc. among these, the damages related to the airbag impact which is subset of mechanical damages, take a significant percentage. Presenting a model of human eye in car airbag blunt impacts during accident could be effective for receiving helpful information from damage of the internal parts...
Analysis of Contact Geometry Effect on the Slip Amplitude in Fretting Fatigue of a Turbine Blade Root
, M.Sc. Thesis Sharif University of Technology ; Adibnazari, Saeed (Supervisor)
Abstract
Turbine blades are exposed to mechanical and thermal stresses due to their operation in critical conditions and get into various damages such as fatigue and wear. These factors reduce the life of the blades and lead to expensive maintenances. As a result, recognizing the type of possible damage helps to increase the life of the blade and to delay the occurrence of failures by taking the necessary actions.The subject of this thesis is to investigate the effect of geometric parameters on the slip amplitude in the root of a turbine blade. In this work, the effect of three parameters of contact area length, contact angle, and coefficient of friction on relative slip amplitude and contact...
Determination of the Equivalent Linear Systems of Nonlinear MDOF Steel Moment Resisting Frames
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofooei, Fayyaz (Supervisor)
Abstract
The purposeof this study isto findthe propertiesof an equivalent linear Multiple Degrees of Freedom (MDOF) system, or so-called substitute structure, that its response is an approximation ofthe target actualnonlinearMDOF structure’s response (Shodja, 2013). In that regard,thestiffness anddampingmatricesofthe substitutestructure are considered as functions ofthe stiffnessand dampingmatrices ofthe actualnonlinear structure. Inthisway,the substitute structurescan be constructedthroughtrial and errorfor structures with different fundamentalperiods, damping ratios and number of floors.Inthat regard, a number of multi-story steel moment resisting frames are considered. The ductilities of these...
Biomechanical simulation of eye-airbag impacts during vehicle accidents
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 232, Issue 7 , 2018 , Pages 699-707 ; 09544119 (ISSN) ; Zohoor, H ; Naserkhaki, S ; Sharif University of Technology
SAGE Publications Ltd
2018
Abstract
Airbags are safety devices in vehicles effectively suppressing passengers’ injuries during accidents. Although there are still many cases of eye injuries reported due to eye-airbag impacts in recent years. Biomechanical approaches are now feasible and can considerably help experts to investigate the issue without ethical concerns. The eye-airbag impact–induced stresses/strains in various components of the eye were found to investigate the risk of injury in different conditions (impact velocity and airbag pressure). Three-dimensional geometry of the eyeball, fat and bony socket as well as the airbag were developed and meshed to develop a finite element model. Nonlinear material properties of...
Optimum mechanism for rehabilitation of fingers
, Article 5th RSI International Conference on Robotics and Mechatronics, IcRoM 2017, 25 October 2017 through 27 October 2017 ; 2018 , Pages 451-456 ; 9781538657034 (ISBN) ; Zohoor, H ; Shirzadi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Nowadays, with the advancement of technology, humans are looking for ways to cure various diseases. Meanwhile, musculoskeletal injuries usually have a long treatment period. Therefore, in recent years, Researchers working one exoskeleton with rehabilitation application which conduct physiotherapy tasks. In current study, a portable two degree of freedom hand exoskeleton is designed which its mechanism is a combination of cable and link mechanism, MCP1 1Metacarpophalangeal joint between metacarpal and proximal phalanges joints move by link mechanism, DIP2 2Distal interphalangeal joint between proximal phalanges and middle phalanges and PIP3 3Proximal interphalangeal joint between middle...
Experimental Study of Water Flow on Migration of DNAPL in Fracture Network: Distribution, Transport and Remediation using Density Modification of Surfactant
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor)
Abstract
Groundwater is one of the vital sources of drinking water worldwide, yet it faces the risk of contamination from organic and inorganic substances. These pollutants can persist in the environment for extended periods, leading to continuous contamination. One of the key factors in the rapid transport of these contaminants is the presence of fracture networks within porous media. These fractures play a crucial role in facilitating the movement of pollutants to deeper layers of groundwater aquifers. The fracture networks enable contaminants to migrate more rapidly and penetrate various regions, complicating pollution management. Additionally, the natural flow of groundwater acts as a driving...
Integration of miniature heat pipes into a proton exchange membrane fuel cell for cooling applications
, Article Heat Transfer Engineering ; Volume 38, Issue 18 , 2017 , Pages 1595-1605 ; 01457632 (ISSN) ; Roshandel, R ; Behshad Shafii, M ; Sharif University of Technology
2017
Abstract
In proton exchange membrane fuel cell (PEMFC) operations, the electrochemical reactions produce a rise in temperature. A fuel cell stack therefore requires an effective cooling system for optimum performance. In this study, miniature heat pipes were applied for cooling in PEMFC. Three alternatives were considered in tests: free convection, forced convection cooling with air, and also water. An analytical model was developed to show the possibility of evoking heat from inside a fuel cell stack with different numbers of miniature heat pipes. An experiment setup was designed and then used for further analysis. The proposed experiment setup consisted of a simulated fuel cell that produced heat...
Integration of Miniature Heat Pipes into a PEM Fuel Cell for Cooling Application
, M.Sc. Thesis Sharif University of Technology ; Roshandel, Ramin (Supervisor) ; Shafii, Mohammad Behshad (Co-Advisor)
Abstract
Due to the operation of proton exchange membrane fuel cell (PEMFC), temperature will rise because of the electrochemical reactions and control of temperature is one of the most important sections that has influence on the performance of the fuel cell. In this study three alternative for cooling and controlling the temperature situation is proposed and compared. the experimental setup consists of the simulated fuel cell that produce heat just like PEMFC and number of thermosyphon miniature heat pipes for evoke the heat and three types of condenser that makes three different scenario for this cooling setup. Free convection, force convection using Fan and force convection using circulating...
Comparison of vibration and acoustic responses in a rotary machine balancing process
, Article Applied Acoustics ; Volume 164 , July , 2020 ; Kasaei, A ; Peplow, A ; Afzali, B ; Shirzadi, E ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Balancing a rotating machine is a vital step towards ensuring it will operate reliably and safely. To achieve this condition monitoring is an important aspect for early faulty detection and it can also result in the improvement of the operational continuity and equipment safety. Imbalance itself, is a common problem in rotating machinery and it can lead to poor or even dangerous vibration levels. And, for example, it is also well known that misalignment can lead to bearing defects. So, in order to overcome these problems many balancing techniques have been developed that are largely based on measured vibration data using accelerometers attached to the faulty device. The three-point method is...