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    Experimental Studies for Construction of a Microbial Fuel Cell (MFC) in Continuous Flow Mode

    , M.Sc. Thesis Sharif University of Technology Sadeghi Haskoo, Mohammad Amin (Author) ; Vossoughi, Manoochehr (Supervisor) ; Aalemzadeh, Iran (Supervisor)
    In this research performance of microbial fuel cells (MFCs) in continuous flow mode was studied. Different anodic chambers were tested and it was found that granular activated carbons (GACs) produced the highest power density (1228 mW/m3) in comparison with multiple anodes (731 mW/m3), single anode (294 mW/m3) and polymeric packings (40 mW/m3). It was also shown that in a plug-anodic chamber (PAC) the power output is reduced by reducing agitation of anodic volume. Adding more GACs to anodic chamber results in power increase, however by increasing occupied volume from 80% to 100% the power increase was negligible in result of cathodic reactions limitations. Feed flowrate was increased from... 

    A Study on Properties of Composite Coating with Al2O3 Base Prepared by Hard Anodizing with ZrO2 Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Motamen, Ali (Author) ; Afshar, Abdollah (Supervisor)
    In this study anodized none composite and composite film containing ZrO2 nanoparticles were prepared on 1050 Al Alloy using hard anodizing method in sulfuric and oxalic acid mixed solution by pulse Currents. The microstructure and properties of the film were studied by field emission scanning electron microscopy with EDS analyzer and XRD diffraction and friction wear test were performed to evaluate the mechanical properties of coating . Results indicate that the composite film with ZrO2 nanoparticles have reduced friction coefficient with high micro hardness friction coefficient of composite film can be small as 0.16 which is much smaller than that 0.39 of none composite film. Micro hardness... 

    Fabrication of a Sensor, Based on TiO2 Nanotubes Modified with Metal Nanoparticles and Carbon and its Application for Detection of Dopamine in Presence of Uric Acid and Ascorbic Acid

    , Ph.D. Dissertation Sharif University of Technology Mahshid, Sara (Author) ; Askari, Masoud (Supervisor) ; Dolati, Abolghasem (Supervisor)
    The present work describes sensing application of modified TiO2 nanotubes towards detection of dopamine. The TiO2 nanotubes electrode was prepared using anodizing method at different conditions, among which NaF/ NaHSO4 solution and voltage of 15 V was chosen as the optimum condition. In order to improve the performance, surface modification with metal nanoparticles (Pd, Pt and Au) and carbon is required using “pulse electrodeposition” and “decomposition of polyethylene glycol at 600 °C” respectively. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. In this regard two type of electrodes were proposed: Pd-Pt-Au-TiO2 and C-Ni(Pt)-TiO2.... 

    Fabrication of Dental Implant from Ti-6Al-4V With Nanostructured Hydroxyapatite Coating

    , M.Sc. Thesis Sharif University of Technology Rahnamaee, Yahya (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    The use of dental implants has grown considerably in recent years in Iran but this piece is the industrial imported parts that are not yet produced in Iran. So the main purpose of this research was to fabricate a dental implant from Ti-6Al-4V alloy by CNC machining techniques. On the other hand, the poor bonding strength of bioactive coatings and low cell growth on the surface of uncoated implants are the common problems in the use of dental implants. So another aim of this study was to investigate the effect of Nanoscale surface topography and nanostructured coatings on the surface modification of titanium implant in order to improve Osseointegration and the bonding strength of bioactive... 

    Synthesis of Doped Titania Nanotube Arrays by Anodizing of Titanium and Surveying of their band Gap

    , M.Sc. Thesis Sharif University of Technology Meftahi, Mohammad (Author) ; Ghorbani, Mohammad (Supervisor)
    In recent decade, photocatalystic properties of titania nanotube and its mechanisms has been considered greatly in many researches. One of the major ways to increase photocatalystic properties and extending the usage of TNTs is doping them with various elements and modifying their band structure. In present research doped TNTs were prepared by doping of Molybdenum, Nitrogen, and Carbon elements by anodizing method in about of 35 degrees of centigrade and constant voltage of 20V on the surface of titanium sheet. Structural and photocatalystic properties of as-prepared TNTs were studied using field emission scanning electron microscope (FESEM), x-ray diffraction (XRD), energy dispersive... 

    Surface Modification of Metallic Implants and Improvement of their Biological Properties in Presence of Bioactive Ceramic Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Riahi, Zohreh (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    By consideration of increasing demands to use implants and efforts to get technical knowledge and localization of this implants, considerable research in this field is needed. Therefore, presentation of a coating which is able to provide parameters needed for an acceptable implant is the aim of this study. In this direction, modification of surface of metallic implants in order to achieve nanotubes of titanium oxide, with the purpose of providing biocompatibility was done. On the other hand, because chronic infection of the implant’s surrounding is one of the main important reasons in rejection of implants, 〖TiO〗_2 nanotubes as a drug carrier were used in order to solve this problem. So,... 

    Electrophoretic Deposition of Functionally Graded NiO/YSZ for SOFC Anode Fabrication

    , M.Sc. Thesis Sharif University of Technology Zarabian, Mina (Author) ; Faghihi Sani, Mohammad Ali (Supervisor) ; Simchi, Abdolreza (Supervisor)
    The future crisis and environmental pollution led to increasing interest in alternative energy conversion systems such as solid oxide fuel cell (SOFC). One of the main obstacles in using SOFCs is their relatively high fabrication cost compared with their low amount of produced energy .Therefore, in the present study, fabrication of a more cost-efficient functionally graded NiO-YSZ composite for SOFC anode by electrophoretic deposition (EPD) method was investigated. In this research, the effect of different chemical parameters such as media, additives, particle size distribution and nano NiO addition were initially investigated on the stability of NiO-YSZ suspension by Zetasizer and turbidity... 

    Hydroxyapatite Coating on Nanotubes TiO2

    , M.Sc. Thesis Sharif University of Technology Goodarzi, Mena (Author) ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
    There are many techniques that have been used to create hydroxyapatite nanoparticles coating on nanotubes. Electrophoretic deposition (EPD) is one of the methods that has advantages of short formation time, needs simple apparatus, little restriction of the shape of substrate, no requirement for binder burnout as the green coating contains few or no organics. In the research, first, titanium dioxide nanotubes were fabricated by anodic oxidation. Anodizing voltage effect on the morphology of nanotubes was evaluated. SEM images was shown that in the anodizing voltage 20V, nanotubes were the most regular. Then, Hydroxyapatite nanoparticles has been deposited onto nanotublar TiO2 by... 

    Design and Manufacture of Nanostructured Hydroxyapatite coated Foamy core@compact Shell Ti-6Al-4V Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Ahmadi Seyedkhani, Shahab (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    The main purpose of this research is design and manufacture of nanostructured hydroxyapatite-coated foamy core@compact shell Ti-6Al-4V bone-like composites for utilization as substitutive implant for cortical bone having porous core. The production procedure consist of two steps; (a) fabrication of foamy core@compact shell Ti-6Al-4V alloy using powder metallurgy-space holder technique, (b) precipitation of hydroxyapatite on the Ti-6Al-4V alloy specimens via pulse electrodeposition process. The bone-like structures were designed to reduce the stress shielding which ensures long-term stabilization of implants. It is while that, the hydroxyapatite coating improve the biological response of... 

    Electrochemical Behaviors of RuO2-TiO2 Mixed Metal Oxide Coated on Titanium Anodes in Chlor-Alkali Electrolysis

    , M.Sc. Thesis Sharif University of Technology Paryani, Kasra (Author) ; Ghorbani, Mohammad (Supervisor)
    Titanium anodes activated by noble metal oxides under the trade name of dimensionally stable anodes (DSAs) are widely used in the electrolytic industry, particularly in chlor – alkali electrolysis. Over 20 years of use, the fundamental aspects of their long – lasting performance are not fully understand and the corrosion mechanisms are still the subject of many investigations. RuO2 – TiO2 coatings on titanium substrate, due to proper electrochemical characteristics and good corrosion resistance, is most applicable as an anode in chlor – alkali systems. In the present investigation, the first layer of Pt – Ir coating is applied via electrodeposition method on the pretreated titanium substrate... 

    Desulfurization of Petroleum Coke in Aluminium Industry

    , M.Sc. Thesis Sharif University of Technology Askari, Hadis (Author) ; Khorasheh, Farhad (Supervisor) ; Soltanali, Saeed (Supervisor) ; Baghalha, Morteza (Co-Advisor) ; Tayebi, Shokufeh (Co-Advisor)
    In this study, desulfurization of petroleum coke has been investigated for use in aluminum industry. To reduce sulfur content in petroleum coke, desulfurization has been investigated by two methods of solvent extraction and molten caustic leaching. The method of molten caustic leaching at temperatures of 400-600 °C has been investigated. Other effective parameters on the desulfurization of petroleum coke are the mass ratio of alkali to feed (petroleum coke) in the range of 0.5-1.5 and the time of 1-3 hour and the mesh size of 200-600 micron. In this study, the conditions of desulfurization of petroleum coke using potassium hydroxide have been investigated. Results show that by using the... 

    Increasing Critical Heat Flux and Boiling Heat Transfer on Superhydrophilic Nano Porous Surface Using Low Conductive Spots

    , M.Sc. Thesis Sharif University of Technology Najafpour, Sahand (Author) ; Mousavi, Ali (Supervisor)
    This dissertation argues that bi-conductive textured surfaces increase both Critical Heat Flux (CHF) and Heat Transfer Coefficient (HTC) simultaneously. Surface modification is applied to stainless steel specimens by the anodizing method in an electrolyte containing Ammonium Fluoride and DI-Water and Ethylene Glycol as the based solvent. The process of oxidation was under constant DC voltage and constant temperature. The contact angle on self-aligned Nano-porous oxide layer fabricated on the substrate substantially decreases to about 5.7 degree which has a dramatic effect on CHF. Furthermore, the oxide layer augments the boiling efficiency by increasing the number of active sites and... 

    The Impedimetric Human Papiloma Virous DNA Biosensor Fabrication Based on Gold Nanotubes

    , Ph.D. Dissertation Sharif University of Technology Shariati, Mohsen (Author) ; Ghorbani, Mohammad (Supervisor) ; Sasanpour, Pezhman (Supervisor)
    An impedimetric human papilloma virus (HPV) DNA biosensor based on gold nanotubes (AuNTs) in label free detection was materialized. The AuNTs decorated nanoporous polycarbonate (AuNTs-PC) template as biosensor electrode was fabricated by electrodeposition method. The single strand DNA (ss-DNA) probe was covalently immobilized onto the AuNTs-PC electrode. The hybridization of target sequences with the ss-DNA probe was observed by the electrochemical impedance spectroscopy (EIS). The biosensor showed high selectivity and could differentiate between the complementary, mismatch and non-complementary DNA sequences. The EIS measurements were matched to Randle's equivalent circuit. The... 

    Lithium Extraction with TiO2 Nanotube Synthesized by Anodizing Method

    , M.Sc. Thesis Sharif University of Technology Taghvaei, Nastaran (Author) ; Askari, Masoud (Supervisor)
    Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake... 

    Kineticts of formation of Titania Nanotubes and Silk Fibroin on Titanium-based Metal for Investigating the Drug Release Behavior

    , M.Sc. Thesis Sharif University of Technology Goudarzi, Arghavan (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    In recent decades, due to the significant growth of implants’ application and considering the infection of the implants as the most momentous factor in implantation failure, study on the controlled drug release and other biologically active agents in modern drug delivery systems has attracted many kinds of research throughout the world and efforts are being made to use regulated drug delivery systems for implantation which is also the purpose of this current scientific work.To achieve this, the anodizing process was used to fabricate titanium oxide nanotubes (TNTs) to increase the absorption capacity of the drug in the implants and these TNTs were formed regularly and uniformly in an organic... 

    Preparation and Characterization of Ternary Mixed Oxide Containing IrO2,RuO2,TiO2 on Platinum Coated Titanium Anode

    , M.Sc. Thesis Sharif University of Technology Ali Asghari, Sepideh (Author) ; Ghorbani, Mohammad (Supervisor) ; Davami, Parviz (Supervisor)
    Ruthenium based-oxide coatings on Titanium anodes are widely used as DSA (Dimensionally Stable Anode) for chlorine and chlorate production. Coatings consisting of composition of highly conductive oxide of noble metals (Ru, Ir and Pt) make them as long lasting anodes in chlor-alkali technology.In this work, a newly anode by a ternary coating of IrO2, RuO2, and TiO2 on the Pt-coated Ti was developed through thermal decomposition of iridium and titanium and ruthenium inorganic salts dissolved in n-pentane. The effect of deposition parameters such as current density, time, different condition of baking, heating, mole ratio and pulling up the samples was investigated to find out reasonable... 

    Optimization of Nanostructures for Electron Emission

    , Ph.D. Dissertation Sharif University of Technology Yasrebi, Navid (Author) ; Rashidian, Bizhan (Supervisor)
    The need for better characterization systems (electron microscopes) and high resolution lithography systems, have made electron beams systems an interesting choice for research and development. In fact, all of the above applications require ideal electron beams (beams with minimum energy spread, maximum current density, and minimum spotsize), and electron-optic lenses (simple lenses with minimum aberration). In this research, theoretical aspects of electron emission and lens systems are reviewed. Field emission array (FEA) electron guns are introduced as electron sources with minimum energy spread, and a new simulation method is presented in order to minimize the complexity, and reduce the... 

    Experimental Study of Hydrogen Production from Dairy Wastewater in the Annular Microbial Electrolysis Cell (AMEC)with Spiral Anode

    , M.Sc. Thesis Sharif University of Technology Hassany, Masoud (Author) ; Yaghmaei, Soheila (Supervisor)
    In this project, energy in form of electricity and hydrogen was produced in microbial fuel cell and microbial electrolysis cell respectively. For reducing costs, a stainless steel mesh with graphite coating was used as anode electode. Also for increasing efficiency, anode was positioned in cells in a spiral mode. Efficiency of cells was investigated in batch and continuous mode. In this research, dairy wastewater was used as substrate.This wastewater not only has severe emissions, but also is high energy content. In the field of dairy wastewater treatment and hydrogen production in an microbial electrolysis cell wasn’t observed any article.At the first, wastewater was treated in two... 

    Investigation of Si3n4 Nano Particle Addition on the Hardening Behavior of Anodized Coated 1050 Aluminum Alloy

    , M.Sc. Thesis Sharif University of Technology Mohammadi Dehcheshmeh, Iman (Author) ; Afshar, Abdollah (Supervisor)
    In the present study, it has been tried out to increase the hardness and wear resistance of anodized aluminum coating byadding Si3N4 nanoparticles to the anodizing bath and making a composite coating. In order to investigate the influence of other effective parameters on the properties of anodized coating before the compositing process, hardness and thickness were optimized in the Sulphoric/oxalic bath using design of experimental method (central composite design). The properties of these coatings are dependent on various parameters among which time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were considered in the present study. Analysis of... 

    Influence of Cobalt and Vanadium Dopants on the Performance of TiO2(B) Nanowires used as anode Materials in Lithium-ion Batteries

    , M.Sc. Thesis Sharif University of Technology Amirsalehi, Mahmoud (Author) ; Askari, Masoud (Supervisor)
    Li-ion batteries have been widely applied as power sources for portable electronic devices. Recently, Li-ion batteries are considered as the most promising energy storage technology for electric vehicle applications however, fundamental improvements are needed. TiO2 (B) is attractive candidate for anodes in rechargeable Li-ion batteries, due to their low cost, non-toxicity and favorable channel structure for fast lithium mobility. It is predicted that synthesis of doped nanostructure of this material, through reducing the diffusion pathway and formation of crystal defects, will increase the capacity of TiO2(B). In this investigation, Co and V doped TiO2(B) nanowires are synthesized by...