Search for: peroxide
0.007 seconds
Total 98 records

    Experimental Investigation of a Monopropellant Thruster Using Hydrogen Peroxide

    , M.Sc. Thesis Sharif University of Technology Nikfar, Rouzbeh (Author) ; Farahani, Mohammad (Supervisor)
    Monopropellant thrusters are one of the most common types of propulsion systems that are used extensively in space applications. Especially thrusters with a capacity of less than 50N, they are used on space satellites and are developing rapidly. Problems such as contamination, toxicity of the propellant, difficulty in storing and custody, as well as price, led to the removal of the hydrazine from the focus of attention and focus on green propulsion. One of these, is the green propellant of hydrogen peroxide, which is decomposed in the proper catalytic vicinity, and the only chemical decomposition products are oxygen and water vapour. The present study aims to design and construct mono... 

    Investigation the Effect of Antioxidant on Amount of Crosslink and Mechanical Behavior of Peroxide Crossliked Polyethylene (PEX-A)

    , M.Sc. Thesis Sharif University of Technology Berarzadeh Grivdehy, Meisam (Author) ; Pircheraghi, Gholamreza (Supervisor)
    Polyethylene is the most widely used plastic material in the world for reasons such as lightweight, good strength, good processability, low cost, and low maintenance cost, and very good chemical resistance. One of the applications of polyethylene that has received much attention in recent decades is its use in the manufacture of hot water pipes. To maintain the properties of polyethylene at high temperatures, it must be crosslinked at a proper level. Appropriate antioxidants should be used to prevent the degradation and oxidation of polyethylene during the process as well as long-term operation. Concomitant use of phenolic antioxidants for long-term stability during service and phosphorus... 

    A Study on Morphology, Structure and Properties of Silver and Gold Coatings Applied by a Chemical Reduction Deposition Method Using Double-Spray Device

    , M.Sc. Thesis Sharif University of Technology Bakhshizadeh, Ali (Author) ; Dolati, Abolghasem (Supervisor)
    Silver and gold are precious, expensive metals and are used in various applications, such as jewellery and ornamentals, electronics and optics. In the present study, soda-lime glass surfaces firstly were activated with acidic stannous chloride solution. Then, silver and gold were coated on these surfaces via simultaneous spraying of two solution: A silver- or gold-complex bearing solution and a reducing agent (Dextrose for Ag and H2O2 for Au) bearing solution. For silver coating, the effect of various parameters such as time, reducing agent concentration, number of passes, presence and concentration of Urotrpin and Decamethylcyclopentasiloxane (DMCPS) as microstructural modifiers and... 

    Solphate Leaching of Titanium Minerals from Shore Reservoir of in the North of Iran and Refining of Iron and other Impurities

    , M.Sc. Thesis Sharif University of Technology Behvar, Alireza (Author) ; Yoozbashizadeh, Hossein (Supervisor)
    The most important raw material for production of titanium dioxide is titanium that used in Aerospace, Plastic, Pigment and Pharmacy industries. Due to the presence of titanium minerals in Iran, reduce imports of titanium dioxide is one of the goals of the Ministry of Industries and Mines to achieve self-sufficiency in the production of TiO2.One of the very rich sources of titanium is alluvial sands in northern of Iran. In this study the TiO2 high grade pigment production from these sources has been investigated. Titanium-bearing sands with 9.5% TiO2 are used to produce high grade TiO2 pigment. After magnetic separation stage and reach a purity of 16.2% TiO2, upgrading slag step is not... 

    Design of Scaffolds with Multi-scale Engineered Microchannels

    , M.Sc. Thesis Sharif University of Technology Mollajavadi, Mohammad Yasin (Author) ; Saadatmand, Maryam (Supervisor)
    Building complex and functional tissues and organs is very challenging. One of the challenges is building an efficient network of blood vessels that can be used to facilitate the transport of nutrients and oxygen to the host. In addition to using channels for oxygen supply, another solution is to use oxygen-carrying materials. In this study, in addition to designing and simulating scaffolds with multi-scale microchannels, calcium peroxide was used to release oxygen and eliminate hypoxia in the scaffold. Here alginate is used as the main material for scaffolding. In an attempt to build a scaffold using a bio-printer, pluronic acid was also used as a sacrificial material to create canals.... 

    Study and Preparation of Suitable Polymer Compound for Radiation Masks

    , M.Sc. Thesis Sharif University of Technology Almas Ganj, Ali (Author) ; Mosavi Soghondikolaei, Abbas (Supervisor)
    External radiotherapy is a major method of treating cancer. In this method, penetrating rays such as X-rays, alpha, beta and gamma emitted from the device are used to treat cancer. In order to emitting rays only to the cancer cells, masks are used to stabilize the patient's body in the right position during the radiotherapy, so that the rays are not emitted to the healthy tissues of the patient's body. In this dissertation, first, different methods of making radiotherapy masks are examined. Next, polycaprolactone is proposed as the main material for making the mask. Due to its low tensile strength, this material alone is not suitable for the intended use. Therefore, the material was cured... 

    Experimental Study on Biosensors for Detection of Biohazards with Nano-structured Metal Oxides Basis

    , M.Sc. Thesis Sharif University of Technology Dadfarmay, Sajad (Author) ; Mashayekhan, Shohreh (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
    In this research, fabrication of a mediator free nano-biosensor for the detection of cyanide has been studied. This biosensor utilizes 75 nm diameter (nano) ZnO particles synthesized with sol- gel method for modification and immobilization of Horseradish peroxidase (HRP). Cyanide plays inhibitory role in decomposition of H2O2 while HRP plays catalyst role in this reaction. Cyanide inhibits enzyme activity thorough binding with enzyme active sites and result in decreasing electrical current in electrochemical decomposition of H2O2. Amperometery response of biosensor shows linear relation between inhibition percent and cyanide concentration in range of 3µM - 24µM with detection limit of 0.62µM... 

    Study and Optimization of Operating Parameters of Nanophotocatalytic Wastewater Treatment Process

    , M.Sc. Thesis Sharif University of Technology Qanbarzadeh, Mojtaba (Author) ; Soltanieh, Mohammad (Supervisor) ; Vossoughi, Manouchehr (Supervisor) ; Feilizadeh, Mehrzad (Co-Advisor)
    In this study, we investigate the effect of adding potassium persulfate (PDS) (K2S2O8) and hydrogen peroxide (H2O2) to E.coli (as a model microorganism) photocatalytic removal system in the presence of the TiO2-P25 as photocatalyst and UV irradiation. In this regard, the PDS and H2O2 oxidants were added separately in the different levels of pH and photocatalyst loading under UV irradiation. The experimental points were determined based on the central composite design (CCD) and in order to study the main and the interactive effects of the photocatalyst concentration (mg/L), oxidant concentration (mg/L) and the pH on the final concentration of E.coli (cfu/mL), a response surface model (RSM)... 

    Rapid Determination of Histamine by an Enzyme-based Microfluidic Biosensor

    , M.Sc. Thesis Sharif University of Technology Moradi, Mohammad Reza (Author) ; Vossoughi, Manouchehr (Supervisor) ; Shamloo, Amir (Supervisor)
    Design, simulation, optimization and manufacturing of an enzyme-based microfluidic biosensor has been carried out during this research to measure histamine concentration in a sample. The designed biosensor is composed of a micro-bioreactor to degrade histamine and yield hydrogen peroxide, and a chemical reactor to measure the amount of hydrogen peroxide, using chemiluminescence methods. The geometry of the bioreactor and chemical reactor is developed through comparison and optimization of several different geometries. In theory, the designed sensor can determine histamine concentration in a range of 10M to 1mM under one minute, with a maximum error of 5%. Designed biosensor is built using... 

    Investigation and Optimization of Degradation Process of Contaminants of Chemical Industrial Wastewater Using Enhanced Nanophotocatalysts under Visible and Solar Light

    , Ph.D. Dissertation Sharif University of Technology Feilizadeh, Mehrzad (Author) ; Vossoughi, Manoochehr (Supervisor) ; Aalemzadeh, Iran (Supervisor)
    Photocatalytic degradation is one of the developing modern and effective methods for decontamination of hazardous pollutants of chemical industrial wastewater. This method has several advantages including the possibility of using free and sustainable energy of sun. However, it is still needed to active photocatalysts under solar light and also the enhancement and optimization of operating parameters, and consequently, these topics are selected as goals of the present thesis. Accordingly in this research, first, to obtain a photocatalyst that is highly efficient (especially under visible and solar light), multi-doping and polyethylene glycol (PEG) were used and for the first time,... 

    Oxidative Desulfurization of Gas Condensate

    , M.Sc. Thesis Sharif University of Technology Keshavarzi, Samaneh (Author) ; Seifkordi, Ali Akbar (Supervisor) ; Bazmi, Mansour (Co-Advisor) ; Ghaedian, Maryam (Co-Advisor)
    Due to increasing environmental concern, special interest has been paid to reduction of organosulfur compounds in transportaion fuels. The sulfur- containing compounds are converted into sulfur oxide, i.e, SOx , during combustion, which is a major source of acid rain and air pollution.Gas condensate is a mixture consisting primarily of pentanes and heavier hydrocarbons which is recovered as a liquid from natural gas. It is a proper hydrocarbon source for producing gasoline, kerosene and gas oil in refineries. In this reseach a gas condensate was used as feedstock for studing oxidative desulfurization (ODS). The influence of various parameters of desulforization including the reaction... 

    Rheological Characterization of Nanocomposite Alloy of Polyethylene/ Polyethylene Vinyl Acetate and Nano Cla

    , M.Sc. Thesis Sharif University of Technology kamali Miab, Sona (Author) ; Ramazani Saadatanadi, Ahmad (Supervisor)
    In this thesis, polyethylene vinyl acetate and polyethylene shrinkable nanocomposite films with different percentages of an organoclay such as 0, 1, 3, 5 and 7% have been prepared via two-steps solution method. Morphological and properties of these films, including permeability and mechanical and rheological properties were investigated. Also the effect of addition of cross linking agent (DCP) was studied. Various tests including XRD, SEM, tensile and rheological properties were studied. XRD tests showed that the distance between a layer of or ganoclay increased to 32 percent. This indicates that the polymer chains between the layers of organoclay could be better. SEM examination showed that... 

    Antioxidant Production from Rice Bran and Optimization of the Process

    , M.Sc. Thesis Sharif University of Technology Arab, Fatemeh (Author) ; Alemzadeh, Iran (Supervisor) ; Maghsoudi, Vida (Supervisor)
    An antioxidant is a molecule capable of preventing the oxidation of other molecules and neutralizing free radicals. Free radicals are the root cause for many human diseases.Rice bran is one of the most important co-products in the rice milling.In this research antioxidant activity of two Iranian rice bran varieties Fajr and Tarem, extracted by three different solvents (methanol, ethanol and ethyl acetate),determined at different time of extraction by measurement of total phenolic content, free radical scavenging, inhabitation of linoleic acid peroxidation and reducing power. The methanolic extract of Fajr rice bran produced strong results in antioxidant activity. The amount of Total... 

    Oxidative Desulfurization of Light Fuel Oils

    , Ph.D. Dissertation Sharif University of Technology Sobati, Mohammad Amin (Author) ; Molaei Dehkordi, Asghar (Supervisor) ; Shahrokhi, Mohammad (Supervisor)
    Oxidative desulfurization (ODS) is one of the desulfurization processes that posseses several important advantages such as mild operating conditions. In the present work, oxidative desulfurization of kerosene with a total sulfur content of 2335 ppm and gas oil with a total sulfur content of 7990 ppm were carefully investigated. By evaluation of different oxidation systems, the hydrogen peroxide-formic acid system was selected for the oxidation of sulfur-containing compounds of the light fuel oils. The effects of main operating parameters of the oxidation system including temperature, hydrogen peroxide to sulfur molar ratio (O/S), and formic acid to sulfur molar ratio (Acid/S) on the... 

    Fabrication of Nanocomposite Modified Materials Based on Bi-Metalic Transition Metal Sulfide Using Copper (I) Oxide Nanospheres as a Catalytic Substrate for Designation of Amperometric Non-Enzymatic Hydrazine and Hydrogen peroxide Sensors

    , M.Sc. Thesis Sharif University of Technology Darvishmehr, Zahra (Author) ; Shahrokhian, Saeed (Supervisor)
    In this study, transition metal sulfide, with a high accessible surface and abundant electroactive centers, was used as an electrocatalyst to fabrication an electrochemical sensor of hydrazine and hydrogen peroxide. the direct growth of thin film of nanocomposite can be considered as an efficient method to modify the electrode surface, and the application of these modified electrodes as electrochemical sensors. the cobalt iron sulfide (CoFeS) nanosheets were directly grown on Cu2O nanospheres in order to design hierarchical nanocomposite by using efficient, inexpensive and fast method. Here, Cu2O nanospheres not only served as substrate, but also steer the CoFeS to attach on nanospheres... 

    Designing a Ratiometric Probe for Naked Eye Detection of Hydrogen Peroxide

    , M.Sc. Thesis Sharif University of Technology Mohammadpour, Fatemeh (Author) ; Hormozinezhad, Mohammad Reza (Supervisor)
    Hydrogen peroxide (H2O2) is of great importance in numerous fields such as pharmaceuticals, mining, textile, environmental and food industry. Therefore, the development of low cost, on-site, and uncomplicated H2O2 sensors are of high interest. To date, colloidal quantum dots (QDs) have been used to detect H2O2 based on the quenching of fluorescence intensity in a single wavelength. However, intensity of fluorescent signal could be easily disturbed by various factors. To overcome these undesirable effects, here, a ratiometric sensor has been developed by adding a second fluorophore (as reference) to QDs. For this purpose TGA-capped CdTe QDs were prepared. To detect H2O2, the ratiometric... 

    Theoretical Investigation of Adsorption & Reactions of H2 , O2&HCO2H on Single Crystal Alloys Surfaces Based on UBI-QEP Method

    , M.Sc. Thesis Sharif University of Technology Shokoohi, Mahdiyeh (Author) ; Gobal, Fereydoon (Supervisor)
    The aim of this project is to investigate the mechanisms of absorption and reactions of H2, O2, HCO2H on the single crystal surfaces of transition metals alloys such as Ni-Cu and Ni-Fe and …as well as the ability to control the properties of the mentioned alloys with change in constitutions percentage. In order to achieve the objectives, Unity Bond Index-Quadratic Exponential Potential, UBI-QEP method have been employed. Using this method, the thermodynamic parameters (heat of adsorption and reaction enthalpy changes) and kinetic parameters (activation energy of the reaction) can be calculated, and using these results, intermediate, and as a result, the mechanism of heterogeneous catalytic... 

    Chemically Modified Electrode Based on Carbon Nanostructures and Metal Nanoparticles: Preparation, Characterization and Application in Determination of the Pharmaceutical and Biological Compounds and Oxygen Reduction at Soft Interfaces Catalyzed by in Situ Generated Reduced Graphene Oxide

    , Ph.D. Dissertation Sharif University of Technology Rastgar Kafshgarkolaei, Shokoufeh (Author) ; Shahrokhian, Saeed (Supervisor)
    In the first part, the preparation of metallic, bi-metallic (alloy or mixtures) and metallic oxide nanoparticles on the substrate of carbon nanostructures (carbon nanotube and graphene based nanosheets) has been performed using chemical and electrochemical procedures. Then, the prepared nanostructures were characterized by electron microscopy, spectroscopy and electrochemical techniques. Finally, the nanofilms have been evaluated for sensing applications as a modifier on the electrode surface for accurate determination of trace amounts of some important pharmaceutical and biological compounds. In the first work, multi-walled carbon nanotubes decorated with Fe3O4 nanoparticles... 

    Aza Michael Addition of Amines to α,β-Unsaturated Compounds and Alkene Epoxidation

    , M.Sc. Thesis Sharif University of Technology Arabali, Taraneh (Author) ; Mahmoudi Hashemi, Mohammad (Supervisor)
    This thesis contains two parts .In the first part a catalyst such as AlCl3/Al20 has been demonstrated to catalyze Michael addition reaction of amines to a,�- unsaturated compounds with high yields , short reaction time and under solvent-free condition.The Michael addition to a,�- unsaturated compounds produces quantitively the mono addition products.The next part is about olefins epoxidation . Alkene epoxidation is a useful reaction in organic synthesis. Epoxides play an important role in industrial intermediates for the production of fine chemicals as well as pharmaceuticals .The hydrogen peroxide has been used as an oxidant because it is considered as an economical and appropriate reagent... 

    Horseradish peroxidase immobilization on amine functionalized carbon nanotubes: direct electrochemistry and bioelectrocatalysis

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 37, Number 2 , 2012 , pp. 161-172 Tasviri, M. (Mahboubeh) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Rafieepour, H. A. (Hossain Ali) ; Sharif University of Technology
    Horseradish peroxidase (HRP) was successfully immobilized on amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2 – TiO2 – CNTs) by a convenient and efficient method. Electrochemical impedance spectroscopy, cyclic voltammetry and amperometry were applied to characterize the HRP/NH2 – TiO2 – CNT nano-composite. These techniques showed that the NH2 – TiO2 – CNTs greatly enhance the electron transfer between HRP and the modified electrode. Owing to the redox reaction of the electroactive centre of HRP, the HRP = NH2 – TiO2 – CNTs modified electrode exhibited a pair of quasi-reversible peaks with a peak-to-peak separation (ΔEp) of 70.6 mV and a formal potential (E 0′) of 367.65 mV...