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    Folic Acid Microencapsulation

    , M.Sc. Thesis Sharif University of Technology Kiaeipour, Pegah (Author) ; Alemzadeh, Iran (Supervisor)
    Abstract
    Most natural folate derivatives are highly sensitive to temperature, oxygen and light and their stability depends on food process condition. Alginate and pectin were evaluated for folic acid encapsulation and increasing its stability. By combining them and optimising encapsulation condition the efficiency was enhanced up to 90% . Furthermore, using polymers in combined form caused decrease in folic acid leakage from capsules in acidic condition of stomach. First of all, the time of encapsulation was measured which was 140-180 minutes. In this study the effect of Calcium Chloride concentration on encapsulation was studied. Therefore, two variables were selected which were pectin to algine... 

    Localization and Control of a Magnetic Device in the Presence of an External Field with Application in Stomach Capsule Endoscopy

    , M.Sc. Thesis Sharif University of Technology Sadeghi Boroujeni, Pouria (Author) ; Vosoughi, Gholamreza (Supervisor) ; Moradi, Hamed (Supervisor) ; Nejat Pishkenari, Hossein (Co-Supervisor)
    Abstract
    Capsule endoscopy is a minimally invasive diagnostic technology for gastrointestinal diseases providing images from the human’s digestion system. Developing a robust and real-time localization algorithm to determine the orientation and position of the endoscopic capsule is a crucial step toward medical diagnostics. In this thesis, we propose a novel model-aided real-time localization approach to estimate the position and orientation of a magnetic endoscopic capsule swimming inside the stomach. In the proposed method, the governing equations of the motion of an ellipsoidal capsule inside the fluid, considering different hydrodynamics interactions, are derived. Then, based on the dynamic... 

    Self-healing epoxy nanocomposite coatings based on dual-encapsulation of nano-carbon hollow spheres with film-forming resin and curing agent

    , Article Composites Part B: Engineering ; Volume 175 , 2019 ; 13598368 (ISSN) Haddadi, S. A ; Ramazani S.A., A ; Mahdavian, M ; Taheri, P ; Mol, J. M. C ; Gonzalez Garcia, Y ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    The ability of an active protective organic coating to restore its protection functionality in case of a coating defect is of pivotal importance to ensure durable performance under demanding corrosive conditions. In this paper, a self-healing epoxy system is fabricated by separate encapsulation of epoxy and polyamine in carbon hollow spheres (CHSs) and the autonomous healing performance of the system applied on mild steel is investigated. CHSs were synthesized via a silica templating method using carbonization of polysaccharide shells formed on the surface of silica templates. Consequently, epoxy and polyamine were loaded in separate capsules by dispersion of CHSs into the dilute solutions... 

    Dynamic Modeling and Localization of a Moving Magnetic Particle in a Fluid for Capsule Endoscopy Application

    , M.Sc. Thesis Sharif University of Technology Mazinani, Ali (Author) ; Nejat Pishkenari, Hossein (Supervisor)
    Abstract
    Endoscopy is a medical operation in which a camera is sent into the patient's body and the physician starts taking pictures at specified times. In the traditional endoscopic procedure, a camera is sent into the body by a guiding wire. This can cause severe pain to the patient. In the newer method, a camera is mounted on a small capsule and the patient swallows the capsule. Then the camera inside the capsule starts taking photos and sends them out. This procedure, in addition to being painless, allows the physician to access the innermost parts of the body or the digestive tract.In capsule endoscopy, unlike the older method, one has to find the position and orientation of the capsule at any... 

    MHC-Peptide Binding Prediction Using a Deep Learning Method with Efficient GPU Implementation Approach

    , M.Sc. Thesis Sharif University of Technology Darvishi, Saeed (Author) ; Koohi, Somayyeh (Supervisor)
    Abstract
    The Major Histocompatibility Complex (MHC) binds to the derived peptides from pathogens to present them to killer T cells on the cell surface. Developing computational methods for accurate, fast, and explainable peptide-MHC binding prediction can facilitate immunotherapies and vaccine development. Various deep learning-based methods rely on feature extraction from the peptide and MHC sequences separately and ignore their valuable binding information. This paper develops a capsule neural network-based method to efficiently capture and model the peptide-MHC complex features to predict the peptide- MHC class I binding. Various evaluations over multiple datasets using popular performance metrics... 

    Breakup of microdroplets in asymmetric T junctions

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 87, Issue 5 , 2013 ; 15393755 (ISSN) Samie, M ; Salari, A ; Shafii, M. B ; Sharif University of Technology
    2013
    Abstract
    Symmetric T junctions have been used widely in microfluidics to generate equal-sized microdroplets, which are applicable in drug delivery systems. A newly proposed method for generating unequal-sized microdroplets at a T junction is investigated theoretically and experimentally. Asymmetric T junctions with branches of identical lengths and different cross sections are utilized for this aim. An equation for the critical breakup of droplets at asymmetric T junctions and one for determining the breakup point of droplets are developed. A good agreement was observed between the theories (present and previous) and the experiments  

    Synthesis and characterization of new biopolymeric microcapsules containing DEHPA-TOPO extractants for separation of uranium from phosphoric acid solutions

    , Article Journal of Microencapsulation ; Volume 28, Issue 4 , 2011 , Pages 248-257 ; 02652048 (ISSN) Outokesh, M ; Tayyebi, A ; Khanchi, A ; Grayeli, F ; Bagheri, G ; Sharif University of Technology
    Abstract
    A novel microcapsule adsorbent for separation of uranium from phosphoric acid solutions was developed by immobilizing the di(2-ethylhexyl) phosphoric acid-trioctyl phosphine oxide extractants in the polymeric matrix of calcium alginate. Physical characterization of the microcapsules was accomplished by scanning electron microscopy and thermogravimetric techniques. Equilibrium experiments revealed that both ion exchange and solvent extraction mechanisms were involved in the adsorption of ions, but the latter prevailed in a wider range of acid concentration. According to the results of kinetics study, at low acidity level, the rate controlling step was slow chemical reaction of ions with the... 

    PH-responsive nanostructured polyaniline capsules for self-healing corrosion protection: the influence of capsule concentration

    , Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3512-3520 ; 10263098 (ISSN) Tavandashti, N. P ; Ghorbani, M ; Shojaei, A ; Mol, J. M. C ; Terryn, H ; Gonzalez Garcia, Y ; Sharif University of Technology
    Abstract
    Nanostructured hollow polyaniline (PANI) capsules are good candidates for encapsulation of corrosion inhibitors and pH-responsive release when incorporated into organic coatings. In previous studies, the corrosion protection performance of PANI capsules, containing organic inhibitor 2-Mercaptobenzothiazole (MBT), was demonstrated. The present work studies the influence of capsule concentrations (i.e., 0.3, 1, and 2 wt%) on the corrosion protection properties of the coating system. Anti-corrosion properties of different coatings were compared by means of Electrochemical Impedance Spectroscopy (EIS) and Scanning Vibrating Electrode Technique (SVET). MBT loaded PANI capsules in epoxy ester... 

    CFD simulation of melting process of phase change materials (PCMs) in a spherical capsule

    , Article International Journal of Refrigeration ; Volume 73 , 2017 , Pages 209-218 ; 01407007 (ISSN) Sattari, H ; Mohebbi, A ; Afsahi, M. M ; Azimi Yancheshme, A ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    The present study is focused on CFD simulation of constrained melting of Phase Change Materials (PCMs) in a spherical container. To investigate the melting process of the PCM, its melting fraction was analyzed at different times. The results indicated the existence of thermally stable layers on the top of the sphere. Moreover, inspection of the calculated temperatures at different points along the vertical axis indicates the existence of some disturbances at the bottom of the sphere due to the natural convection. After the validation of the results, the effects of different parameters such as the surface temperature of the capsule, the initial temperature and the size of the spherical... 

    Free vibrations of functionally graded material cylindrical shell closed with two spherical caps

    , Article Ships and Offshore Structures ; Volume 17, Issue 4 , 2022 , Pages 939-951 ; 17445302 (ISSN) Bagheri, H ; Kiani, Y ; Bagheri, N ; Eslami, M. R ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    Free vibration response of a cylindrical shell closed with two hemispherical caps at the ends (hermit capsule) is analysed in this research. It is assumed that the system of joined shell is made from functionally graded materials (FGM). Properties of the shells are assumed to be graded through the thickness. Cylindrical and hemispherical shells are unified in thickness. To capture the effects of through-the-thickness shear deformations and rotary inertias, first order theory of shells is used. Donnell type of kinematic assumptions are adopted to establish the general equations of motion and the associated boundary and continuity conditions with the aid of Hamilton's principle. The resulting...