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Design and Analysis of a Cell Injection Manipulator Made of a Piezo-Driven Double-Deck Stewart Platform
, M.Sc. Thesis Sharif University of Technology ; Ahmadiyan, Mohammad Taghi (Supervisor)
Abstract
With respect to the introduction of bio-material into cells (transfection) , microinjection is a highly efficient technique amongst existing methodologies. In cell injection, a manipulator injects the needle into a cellwhich is hold by a pipet mechanism. The moving range for the needle in this operation is of centimeter order and the resolution for the needle tip should be less than the cell’s diameter. In this thesis a Stewart system is used as for the manipulator. Stewart systems are used in flight simulators systems for decades, as mechanisms which are capable of providing multi-axis movements. In high accuracy positioning and multi-axis applications Stewart systems are highly reliable....
An Analysis of Private Health Insurance Purchasing Decisions
Of Urban Households in Iran
,
M.Sc. Thesis
Sharif University of Technology
;
Zamani, Shiva
(Supervisor)
;
Souri, Davoud
(Supervisor)
Abstract
In order to better understand the performance of the Iranian health insurance industry, household decisions to purchase private health insurance are analyzed using a two-stage (Heckman) model on Survey of Family Income and Expenditure data. Probit and OLS regressions are used to examine the factors influencing the probability and amount of private health insurance purchased. Generally, factors affecting the probability of having insurance also influence the amount of insurance coverage purchased. The results show the importance of some demographics on the insurance decision, particularly age, gender and marital status. Socio-economic factors such as education, income, employment sector,...
Design and Implementation of a Passive - Active Vibration Isolation System on a Diesel Engine Model
, M.Sc. Thesis Sharif University of Technology ; Durali, Mohammad (Supervisor)
Abstract
This research concentrates on active and passive control of vibrations from a dieselgenerator set. A comprehensive study of the system is performed to design a system to provide minimum vibration transmission from a mid size generator set (300 kw) in a wide frequency range around operating point. The control system consists of two stages, a passive part with mode separation feature and an active part inserting control force by inertial actuators on the intermediate mass. Independence of the performances of passive and active parts of control system and low energy consumption of the active system can be considered as the main advantaged of this system. To evaluate the controller design, a DOF...
Single and double stage sintering of mechanically alloyed powder for nanostructured Ti6Al4V foams usable in cancellous scaffolds
, Article International Heat Treatment and Surface Engineering ; Volume 7, Issue 1 , 2013 , Pages 43-48 ; 17495148 (ISSN) ; Aryana, M ; Hassanzadeh Nemati, N ; Alizadeh, M ; Ebadifar, A ; Sharif University of Technology
2013
Abstract
Mechanical alloying and sintering were used to fabricate nanostructured Ti6Al4V scaffolds of highly controllable pore geometry and fully interconnected porous network. Elemental powders were milled for different periods of time (10, 20, 30, 40 and 60 h), mixed with 40-60 vol.-% of 200-400 μm cuboidal NaCl, compacted at 500-600 MPa and sintered according to single or double stage heat treatment regimes at 790 and 950°C under vacuum. After sintering, the samples were soaked in distilled water to washout the NaCl. Foamy microstructures were obtained showing well shaped biopores and fragmentary embedded micropores. The shape of initial NaCl was copied into the biopores which had highly...
Performance improvement of a double stage switch mode AC voltage regulator
, Article 2012 3rd Power Electronics and Drive Systems Technology, PEDSTC 2012, 15 February 2012 through 16 February 2012 ; February , 2012 , Pages 181-186 ; 9781467301114 (ISBN) ; Karimi, E ; Mokhtari, H ; Yazdian, A ; Sharif University of Technology
2012
Abstract
Widespread use of sensitive loads in industries has required the need for high efficiency voltage regulators in order to provide continuous and fast dynamic adjustable AC voltage. This paper introduces a new control strategy to improve the response time and performance of a double stage switch mode regulator. The proposed strategy responds to input voltage variations quickly and improves the efficiency and performance of the circuit. Results of some simulations are presented and analyzed. Experimental tests on a laboratory prototype verify the excellent performance of the proposed system
Double stage switch mode AC voltage regulator
, Article 2011 2nd Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2011, 16 February 2011 through 17 February 2011 ; February , 2011 , Pages 187-192 ; 9781612844213 (ISBN) ; Yazdian, A ; Mokhtari, H ; Sharif University of Technology
2011
Abstract
Development of high frequency power electronic devices leads to high performance and flexible switch mode AC voltage stabilizers instead of traditional electromechanical types. This paper introduces a novel double stage topology for switch mode AC voltage regulators. The system produces a continuous adjustable isolated AC voltage providing a constant output voltage for sensitive loads. In order to simplify the control strategy, a symmetrical PWM is used. In contrast with conventional AC choppers, the proposed circuit does not need any snubber circuits or voltage and current sensors which leads to a simpler and more reliable circuit. Detailed analysis and simulation results show the...
Wavelet-based 2-D ECG data compression method using SPIHT and VQ coding
, Article EUROCON 2007 - The International Conference on Computer as a Tool, Warsaw, 9 September 2007 through 12 September 2007 ; December , 2007 , Pages 133-137 ; 142440813X (ISBN); 9781424408139 (ISBN) ; Fatemizadeh, E ; Sharif University of Technology
2007
Abstract
An improved wavelet-based 2-D ECG data compression method is presented which employs a double stage compression. In the first stage the set partitioning in hierarchical trees (SPIHT) algorithm is used to compress the 2-D data array formed by cutting and beat-aligning the heartbeat data sequence. In the second stage vector quantization is applied to the residual image obtained from the previous stage. The 2-D approach utilizes both inter-beat and inter-sample redundancies in the ECG signal The proposed algorithm is applied to several records in the MIT-BIH arrhythmia database. Results show lower Percent Root mean square Difference (PRD) than 1-D methods and several 2-D methods for the same...