Loading...
Search for: new-design
0.006 seconds

    Conceptual design of a miniaturized hybrid local actuator for Minimally Invasive Robotic Surgery (MIRS) instruments

    , Article Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ; 2011 , Pages 2140-2143 ; 1557170X (ISSN); 9781424441211 (ISBN) Saedi, S ; Mirbagheri, A ; Farahmand, F ; Sharif University of Technology
    Abstract
    The actuation mechanism of the tip of an endoscopic instrument is a major problem in designing miniature scale motorized instruments, especially when a high level of functionality and multi degrees of freedom (DOF) are concerned. We evaluated the different possible actuation methods for an endoscopic needle holder and proposed a new design of hybrid local-actuation, including a micro DC motor and a piezoelectric (PZT) actuator. The DC motor provided the long movement course required for opening-closing function of the gripper while the PZT guaranteed the high gripping force required for holding the needle. A compact serial configuration was considered for the actuators, producing an overall... 

    An optimization-oriented green design for methanol plants

    , Article Journal of Chemical Technology and Biotechnology ; Volume 87, Issue 8 , 2012 , Pages 1111-1120 ; 02682575 (ISSN) Taghdisian, H ; Farhadi, F ; Pishvaie, M. R ; Sharif University of Technology
    Wiley  2012
    Abstract
    Background: A new design for a methanol plant is proposed in which CO 2 addition, as one of the important parameters, is used to optimize the synthesis gas composition. An attempt has been made to assess the environmental features as well as the process operability of the proposed plant, in which the required CO 2 is provided from reformer flue gas. As a starting point, simulation of a conventional reference methanol case (RMC) and also the proposed green integrated methanol case (GIMC) are performed to obtain operational and kinetic parameters. In order to compare properly GIMC and RMC, the objective function is defined so that SynGas production, and thereby methanol production, in the GIMC... 

    Proposal of a new design for valveless micropumps

    , Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1261-1266 ; 10263098 (ISSN) Afrasiab, H ; Movahhedy, M. R ; Assempour, A ; Sharif University of Technology
    2011
    Abstract
    A new design for a valveless micropumping device has been proposed that integrates two existing pumping technologies, namely, the wall induced traveling wave and the obstacle-type valveless micropump. The liquid in the microchannel is transported by generating a traveling wave on the channel, while the placing of two asymmetric trapezoid obstacles, along the centerline of the channel inlet and outlet, leads to a significant (up to seven times) increase of the net flow rate of the device. The effectiveness of this innovative design has been proved through a verified three-dimensional finite element model. FluidStructure Interaction (FSI) analysis is performed in the framework of an Arbitrary... 

    Discharge characteristics of a modified oblique side weir in subcritical flow

    , Article Flow Measurement and Instrumentation ; Volume 22, Issue 5 , October , 2011 , Pages 370-376 ; 09555986 (ISSN) Borghei, S. M ; Parvaneh, A ; Sharif University of Technology
    2011
    Abstract
    Side weirs are frequently used in many water projects. Due to their position with respect to the flow direction, side weirs are categorized as plain, oblique and labyrinth. One of the advantages of an oblique side weir is the increase in the effective length of the weir for overflowing and, therefore, diverting more discharge with the same channel opening, weir height and flow properties (i.e., upstream discharge, upstream Froude number and so on). In this paper, an experimental set-up of a new design of an oblique side weir with asymmetric geometry has been studied. The hydraulic behavior of this kind of oblique side weir, with a constant opening length, different weir heights and... 

    Modification and optimization of benzene alkylation process for production of ethylbenzene

    , Article Chemical Engineering and Processing: Process Intensification ; Volume 50, Issue 1 , 2011 , Pages 31-36 ; 02552701 (ISSN) Ebrahimi, A. N ; Sharak, A. Z ; Mousavi, S. A ; Aghazadeh, F ; Soltani, A ; Sharif University of Technology
    Abstract
    In this paper, an industrial ethylbenzene production unit has been simulated and the results are compared against five-day experimental data. According to prevailing unit condition, i.e. recycled ratio of benzene, benzene selectivity, and energy consumption, the unit is not working under its optimum conditions for minimum cost of ethylbenzene production. In the current design, high amount of benzene recycle (6:1) causes to have an additional cost due to fractionation of ethylbenzene from benzene. A new approach is proposed to modify the benzene alkylation process and reduce the unit's energy consumption. In the newly designed scheme, two double-bed alkylation reactors converted into four... 

    Innovative approach to design a new national low speed wind tunnel

    , Article International Journal of Environmental Science and Technology ; Volume 6, Issue 1 , 2009 , Pages 23-34 ; 17351472 (ISSN) Abbaspour, M ; Shojaee, M. N ; Sharif University of Technology
    2009
    Abstract
    A new multipurpose wind tunnel with adjustable test section designed in the science and research branch of Islamic Azad University site could be used either as the environmental, subsonic or climatic wind tunnels. For this purpose, a new design approach was adopted in which through the adjustment of the wind tunnel cycle, i.e. the nozzle of test section,it could be utilized as any of the three wind tunnels. A design used for environmental wind tunnels and other contraction which was adjusted by 50 % through changes in the polynomial contraction for other applications. As a result, the best fitted profile for the environmental wind tunnels contraction was selected by contraction best fit... 

    Failure analysis of bolted joints in foam-core sandwich composites

    , Article Journal of Reinforced Plastics and Composites ; Volume 27, Issue 15 , 2008 , Pages 1635-1647 ; 07316844 (ISSN) Zabihpoor, M ; Moslemian, R ; Afshin, M ; Nazemi, M. H ; Sharif University of Technology
    2008
    Abstract
    This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed. These solid laminates include a number of glass plies with total thickness equal to core thickness. The effect of solid laminate size and interface angle of foam-solid laminate in the bonding zone on the bearing strength, failure loads and type of modes are investigated. The numerical study is performed using 3D FEM in ANSYS commercial code. Tsai-Wu failure criterion is used in the failure analysis. The... 

    Developing a neural network model for magnetic yoke structure

    , Article 2008 IEEE International Conference on Computational Intelligence for Measurement Systems and Applications, IEEE CIMSA 2008, Istanbul, 14 July 2008 through 16 July 2008 ; 2008 , Pages 75-78 ; 9781424423064 (ISBN) Ravanbod, H ; Norouzi, E ; Sharif University of Technology
    2008
    Abstract
    Magnetic flux leakage technique is used extensively to detect and characterize defects in natural gas and oil transmission pipelines. The amount of magnetic flux introduced into the test sample is an important factor in the resolution of flaw detection. It depends on the power of permanent magnets and the geometrical design of the magnetic yoke. Finite element method (FEM) is the most widely used method of analyzing magnetic yoke due to its power, accuracy and straightforwardness. On the other hand its calculations are so complicated and time consuming, and every single modification in the parameters of the problem requires a new run. In this paper, we present an innovative method to... 

    Innovative method in seismic design of slab-on-girder steel bridges

    , Article Journal of Constructional Steel Research ; Volume 64, Issue 12 , 2008 , Pages 1420-1435 ; 0143974X (ISSN) Lotfollahi, M ; Mofid, M ; Sharif University of Technology
    2008
    Abstract
    Most slab-on-girder steel bridges have been designed and constructed without seismic resistance consideration; as a result, their members, connections, and more commonly their substructure are not sized and detailed to provide the required ductile response needed during major earthquakes. A ductile seismic retrofit solution proposed in this investigation consist of converting of existing end diaphragms into ductile end diaphragms and replacing the end cross-frames and the lower lateral-braced panels adjacent to the supports by special ductile diaphragms. Consequently, this creates ductile fuses to protect the rest of the super- and substructure. This paper illustrates the typical seismic...