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    Design and simulation of an integrated centrifugal microfluidic device for CTCs separation and cell lysis

    , Article Micromachines ; Volume 11, Issue 7 , July , 2020 Nasiri, R ; Shamloo, A ; Akbari, J ; Tebon, P ; Dokmeci, M. R ; Ahadian, S ; Sharif University of Technology
    MDPI AG  2020
    Separation of circulating tumor cells (CTCs) from blood samples and subsequent DNA extraction from these cells play a crucial role in cancer research and drug discovery. Microfluidics is a versatile technology that has been applied to create niche solutions to biomedical applications, such as cell separation and mixing, droplet generation, bioprinting, and organs on a chip. Centrifugal microfluidic biochips created on compact disks show great potential in processing biological samples for point of care diagnostics. This study investigates the design and numerical simulation of an integrated microfluidic device, including a cell separation unit for isolating CTCs from a blood sample and a... 

    Modeling and Developing a Control System for Centrifigual Compressors

    , M.Sc. Thesis Sharif University of Technology Rajabi, Alireza (Author) ; Ghorbanian, Kaveh (Supervisor)
    Compression systems are widely used in industry. Dynamic Modeling is a necessary step in design procedure of a safe compression system. A dynamic model should be adequate and simulate dominant elements of system. One important element of industrial compression systems is downstream pipelines. In this work, a dynamic model including pipeline acoustics is developed. It is accepted that changes of working gas molecular weight can cause inception of instabilities in compression systems. The dynamic model used to study mechanisms of these instabilities. A conventional control system is modeled and tuned for the compression system. The ability of this control system to prevent such instabilities... 

    Effective Factors on the Shrinkage Porosity Defect of Ductile Iron in Centrifugal Casting

    , M.Sc. Thesis Sharif University of Technology Maghsoudi, Mohammad Mahdi (Author) ; Varahram, Naser (Supervisor) ; Davami, Parviz (Supervisor)
    The present work has been planned to elaborately investigate the key parameters which affect the formation of shrinkage porosities during centrifugal casting of ductile cast iron pipes. The porosity defects can be mostly found in the Hot Mould centrifugal casting products and adversely affect the final mechanical properties of ductile iron pipes namely Ultimate Tensile Strength and Elongation.
    In the first point of view, the created defects were detected through microstructural observations and the corresponding responsible mechanisms were also discussed. The results showed that the inner porosity is produced because solidification occurs from both the inner and outer surfaces... 

    Design and Manufacturing of Left Ventricular Assist Device for Patients Undergoing Cardiac Surgery

    , M.Sc. Thesis Sharif University of Technology Ahmadidoust, Ehsan (Author) ; Ahmadian, Mohammad Taghi (Supervisor) ; Firouzbakhsh, Keikhosrow (Supervisor)
    The heart is a powerful muscle whose primary function is to pump blood into the body. many cardiac patients reach a stage that can no longer be kept function of their heart to a satisfactory level by using medication thus doctors undergo surgery. The common problem occurs to most patients undergoing cardiac surgery is that after the surgery, the patient's heart during a short period of time is unable to supply blood with the flow rate and pressure required for all organs, especially the end organs of the body. In this conditions, ventricular assist device help the patients. These devices are used parallel with patient’s heart and supply the large portion of blood that patient’s body needs.... 

    Design, Simulation and Fabrication of a Centrifugal Microfluidic Device for Circulating Tumor Cells Separation

    , M.Sc. Thesis Sharif University of Technology Naghdloo, Amin (Author) ; Shamloo, Amir (Supervisor) ; Nouri Borujerdi, Ali (Supervisor)
    In this project, two centrifugal microfluidic platforms with the goal of separation and genetical study of circulating tumor cells have been designed, simulated and fabricated. Circulating tumor cells are the ones that are detached from the cancer tumors, entered the blood and disseminated the danger of cancer through other parts of the body. Both passive and active methods of separation are investigated in this study. The passive method is based on the inertial effects of the fluid and the active method is based on the magnetophoretic force exerted from an external magnetic field. In order to use the active method, the magnetic nanoparticles are attached to the breast cancer cells by the... 

    Design, Simulation and Fabrication of Integrated Centrifugal Microfluidic Platform for Separation and Lysis of Circulating Tumor Cells

    , M.Sc. Thesis Sharif University of Technology Momeni, Maede (Author) ; Shamloo, Amir (Supervisor) ; Firoozbakhsh, Keykhosrow (Supervisor)
    Cancer diagnosis area has recently been in the limelight of the medical research and there exist an unremitting focus on the devices & technologies which enable cancer detection in its victims. Lately a genius diagnostic method based on isolation and entrapment of circulating tumor cells has been developed which pave the path for cancer identification. These circulating cells which are detached from the primary tumor are carried out through body by means of circulation system. They play key role in phenomenon called metastasis. Separating these rare cells from multifarious background blood cells, assessing their quantity can supply valuable information on the stage of disease as well as its... 

    Innovation of Flexible String and Ball-Spine Inverse Design Methods for 2D and Axisymmentric Internal Flows

    , Ph.D. Dissertation Sharif University of Technology Nili Ahmadabadi, Mahdi (Author) ; Hajilouy Benisi, Ali (Supervisor) ; Dor Ali, Mohammad (Supervisor) ; Ghadak, Farhad (Supervisor)
    Duct Inverse design problems usually involve finding the wall shape associated with a prescribed distribution of wall pressure or velocity. In this investigation, a novel iterative inverse design method is presented and developed for internal flows. In the proposed method, the duct walls shape is changed under a novel algorithm based on the deformation of a virtual flexible string in flow. The deformation of the string due to the local flow conditions resulting from changes in wall geometry is observed until the target shape satisfying the prescribed wall’s pressure distribution is reached. The flow field at each step is analyzed to obtain the current pressure distribution along the wall.... 

    Design of a Supercritical Carbon Dioxide Centrifugal Compressor

    , M.Sc. Thesis Sharif University of Technology Shuli Shamsabad, Amin (Author) ; Ghorbanian, Kaveh (Supervisor)
    Thermodynamic properties of supercritical carbon dioxide change near the critical point. High cycle efficiency is realized by having the main compressor to operate near the critical point of CO_2 to benefit from reduced compression work. In addition the high efficiency, compactness, nontoxicity, cheap working fluid and possibility of using dry cooling instead of wet cooling, s-CO_2 has many application such as nuclear, fossil fuel, renewable sources like solar thermal and waste heat. With regards to sCO_2 thermodynamic properties, suitable equation of state with high accuracy has been determined, and then is used in the design modeling. Recompression Brayton cycle with steady state flow is... 

    Aerodynamic Instability Modeling of a High Speed Centrifugal Compressor

    , M.Sc. Thesis Sharif University of Technology Saboori, Rozhin (Author) ; Ghorbanian, Kaveh (Supervisor)
    The present thesis investigates the surge phenomenon of high speed centrifugal compressors. Surge is a highly undesired condition and may cause severe damage to the machine and thus the plant. Traditionally, surge is avoided via a surge avoidance scheme wih recycle valve in discharge at the most common approach. A one dimensional technique is developed where the Greitzer lumped parameter model along with the Gravdahl one dimensional model is considered as the basis. Shaft dynamics, volume dynamics, losses, energy transfer and time lag are imbedded in the present model to improve the prediction of the compressor characteristics beyond the stability region. On the other hand, in order to... 

    Design, Simulation and Construction of a Rapid Gene Amplification Microfluidic Device Using Polymerase Chain Reaction (PCR) Method

    , M.Sc. Thesis Sharif University of Technology Amadeh, Ali (Author) ; Shamloo, Amir (Supervisor)
    Polymerase chain reaction method is a conventional method for obtaining multiple copies of a specified segment in the DNA molecule and to amplify the DNA molecule itself. Therefore, this method has been of paramount importance in different fields of research and has been applied for different applications. PCR requires thermal cycling, or repeated temperature changes between two or three discrete temperatures to amplify specific nucleic acid target sequences. To achieve such thermal cycling, conventional bench-top thermal cyclers generally use a metal heating block powered by Peltier elements or benefit from forced convection heat transfer. Although efforts have been made in order to reduce... 

    The Physical Modeling and Analysis of Seismic Soil-Pile Interaction in Unsaturated Sand Using Geotechincal Centrifuge

    , M.Sc. Thesis Sharif University of Technology Ghadirianniari, Sahar (Author) ; Khosravi, Ali (Supervisor)
    The seismic behavior of pile-supported systems has been an active area of research over the past decades. However, focus has mostly been on evaluating the seismic response of structures embedded in either dry or fully saturated, especially liquefying soil conditions. In this study, a series of dynamic centrifuge tests have been conducted to investigate the effects of soil’s degree of saturation on the seismic behavior of pile-supported superstructures. The scaled physical model tests were carried out on two distinct pile-mass systems embedded in uniform sand layers. A steady state infiltration technique was used to control matric suction profiles in the sand layer prior to shaking. The... 

    Study on Pretreatment of the Uranous Effluents of the UCF & Natanz Plants by Using Supercritical Water Method

    , M.Sc. Thesis Sharif University of Technology Salimi, Ali Akbar (Author) ; Otoukesh, Mohammad (Supervisor) ; Ahmadi, Javad (Co-Advisor)
    Pretreatment of nuclear waste for valuable and limited uranium resources in the nuclear industry as well as environmental protection is imperative. Wash the affected parts of the Natanz uranium enrichment plant uranium centrifuges with a standard cleaning solution of citric acid, a liquid waste is generated in this study, the preparation of these residues using supercritical water oxidation (SCWO) and near critical (HTWO1) was studied as a result, the optimum operating conditions, and conditions of solvent extraction has been studied. In the result, the optimum operating conditions, and conditions of solvent extraction has been introduced. Also in the UCF2 as a liquid waste contaminated with... 

    Design, Manufacturing and Parametric Optimization of a Left Ventricular Assisted Device

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Javad (Author) ; Zohoor, Hassan (Supervisor) ; Firoozbakhsh, Keikhosrow (Supervisor) ; Ahmadian, Mohammad Taghi (Co-Supervisor)
    The heart is a vital part of the body whose primary function is to pump blood throughout the body. The world's leading cause of deaths is due to heart problems. Today, most countries invest heavily in solving these problems and preventing the resulting deaths. One solution for patients with advanced heart disease is to use ventricular assist devices. This device is Used in parallel to the patient's heart, completely or partially replaces the normal functioning of the heart and provides much of the blood needed by the body. The purpose of this study is to design, manufacture and parametrically optimize a ventricular assist pump and its driver system. Since blood is clotted in contact with... 

    Geometrical Modification of a Two-Stage Process Centrifugal Compressor to Improve the Performance Map

    , M.Sc. Thesis Sharif University of Technology Motamed, Mohammad Ali (Author) ; Ghorbanian, Kaveh (Supervisor)
    A Specific process centrifugal compressor is upgraded. The operating range and efficiency pattern are increased. A one-dimensional performance prognosis tool (CCPP) is developed. The tool uses mean streamline method as the analysis model. Since the working media has various components, a complete equation of state is utilized to model the thermodynamic behavior of the real gas in super critical pressures. The performance of the base-line compressor is deyermined. The performance prognosis tool is validated with available experimental data. Upgrade road map and methodology were introduced in accordance to domestic requirements. The performance of the upgraded compressor is investigated and... 

    Optimal design of the volute for a turbocharger radial flow compressor

    , Article Proceedings of the ASME Turbo Expo ; Vol. 2D , 2014 ; ISBN: 9780791845639 Mojaddam, M ; Hajilouy-Benisi, A ; Movahhedy, M. R ; Sharif University of Technology
    In this research the design methods of radial flow compressor volutes are reviewed and the main criterions in volute primary designs are recognized and most effective ones are selected. The effective parameters i.e. spiral cross section area, circumferential area distribution, exit cone and tongue area of the compressor volute are parametrically studied to identifythe optimum values. A numerical model is prepared and verified through experimental data which are obtained from the designed turbocharger test rig. Different volutes are modeled and numerically evaluated using the same impeller and vane-less diffuser. For each model,the volute total pressure ratio, static pressure recovery and... 

    Friction and wear performance of copper-graphite surface composites fabricated by friction stir processing (FSP)

    , Article Wear ; Volume 304, Issue 1-2 , 2013 , Pages 1-12 ; 00431648 (ISSN) Sarmadi, H ; Kokabi, A. H ; Seyed Reihani, S. M ; Sharif University of Technology
    Copper-graphite composites which have low friction coefficient can be used as bearing materials in lieu of materials containing lead which cause environmental problems. So far, some methods such as powder metallurgy and centrifugal casting have been employed to produce these composites. In this study, friction stir processing (FSP) was used to produce copper-graphite surface composites. Five tools with different pin profile were employed in order to achieve a comprehensive dispersion. Results show that the tool with triangular pin gives rise to a better dispersion of graphite particles. Furthermore, four copper-graphite composites containing different graphite content were prepared using... 

    From traditional to fractional PI control: A key for generalization

    , Article IEEE Industrial Electronics Magazine ; Volume 6, Issue 3 , 2012 , Pages 41-51 ; 19324529 (ISSN) Tavazoei, M. S ; Sharif University of Technology
    IEEE  2012
    Proportional-integral (PI) controllers are the most common form of feedback used in industrial applications today [1][3]. The use of proportional and integral feedback also has a long history of practical applications [4]. For example, in the middle of the 18th century, centrifugal governors as the proportional feedback were applied to regulate the speed of windmills [5]. By the 19th century, it was known that using integral feedback could remove the offsets appearing in working with governors [6]. At present, PI control, still a very basic form of feedback, is also one of the first solutions often considered in the control of industrial systems [7]. On the other hand, in some applications,... 

    A speed-dependent variable preload system for high speed spindles

    , Article Precision Engineering ; Volume 40 , April , 2015 , Pages 182-188 ; 01416359 (ISSN) Razban, M ; Movahhedy, M. R ; Sharif University of Technology
    Elsevier Inc  2015
    High speed machine tools are required to operate in a wide range of spindle rotational speeds with high stiffness and high accuracy. The stiffness of the spindle is largely dependent on the axial preload of the angular contact bearings. A large preload is required at lower range of speeds to provide sufficient stiffness for vibration-free heavy cutting. However, at higher speeds, it results in rapid temperature rise and reduces the life of the bearing. For optimum performance, it is essential that the bearing preload is reduced as the rotational speed increases. In this paper, an automatic variable preload system is proposed that changes the preload on the bearings as a function of... 

    Hollow blades for small wind turbines operating at high atitudes

    , Article Journal of Solar Energy Engineering, Transactions of the ASME ; Volume 138, Issue 6 , 2016 ; 01996231 (ISSN) Pourrajabian, A ; Amir Nazmi Afshar, P ; Mirzaei, M ; Ebrahimi, R ; Wood, D. H ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME) 
    Since the air density reduces as altitude increases, operation of small wind turbines (SWTs), which usually have no pitch adjustment, remains challenging at high altitudes due largely to the reduction of starting aerodynamic torque. By reducing the moment of inertia through the use of hollow blades, this study aims to speed up the starting while maintaining the structural integrity of the blades and high output power. A horizontal axis turbine with hollow blades was designed for two sites in Iran with altitude of 500 m and 3000 m. The design variables are the distributions of the chord, twist, and shell thickness and the improvement of output power and starting are the design goals.... 

    Free vibrations of a rotating shell made of p joined cones

    , Article International Journal of Mechanical Sciences ; Volume 124-125 , 2017 , Pages 83-94 ; 00207403 (ISSN) Sarkheil, S ; Saadat Foumani, M ; Navazi, H. M ; Sharif University of Technology
    Elsevier Ltd  2017
    In this paper, a method has been presented to study the free vibration of a rotating shell consisting of p coupled conical shells. This method considers the Coriolis and centrifugal forces as well as the initial hoop tension resulting from rotation of the shell. Matrix transform and power series methods were employed to solve the equations. The advantage of using the matrix transform approach is that the dimension of the coefficient matrix, which is finally constructed to obtain the natural frequencies of a shell made of p cones, remains 8×8. The obtained results were validated with the help of existing special cases of the studied problem reported in the literature, and by means of FEM...