Sharif Digital Repository

Magnesia-Doloma refractories has advantages such as stability in alkaline environments, clean steel production, resistance to acid slag, good cement kiln coating flexibility, low production cost. It also has some weaknesses such as low resistance to thermal shock and quick hydration. In the present study using Birjand Mines Magnesite powders and Dolomites from Zefreh, Esfahan, Magnesia-Doloma clinkers were pressed under the pressure 90 MP and prepared at 1650⁰C in furnace under air atmosphere. The effect of adding 0, 2, 4, 6, and 8% of the Microparticles and Nanoparticles of α-Alumina on microstructure, physical properties, hydration resistance and Thermal shock resistance was studied. Phase... 

Burns are one of the most important accidents related to human health. Due to the intense physical and mental complications and high fatality rate associated with them, receiving proper treatment is of paramount importance. The control of infection in wounds would cure and eliminates the effect of wounds and treatment of skin lesions with engineered scaffolds can be an effective method. The purpose of this project is proposing a hydrogel scaffold based on natural polymers of oxidized alginate and gelatin loaded with an herbal drug to control infection and treat burn wounds. For this purpose, the Iranian Oak extract that it's main content is Tanin and PolyPhenolinc materials, was prepared and... 

In this thesis, the collisions of two fluorine-C60 nanoparticles have been studied using molecular dynamics simulation. The main purpose of this thesis is to present a completely new method based on the definition of the vertical and tangential coefficient of restitution, although by using the combination of the simulation and theory results, we can obtain the approximate parameters of physical properties of nanoparticles, such as hardness coefficient, surface tension, friction coefficient, etc.At first, two fluorine C60 under different conditions, including collision velocity, collision angle, initial temperature, initial rotational angle of the molecule, and various potential applications... 

The properties of 3 nm-diameter fluorinated silica nanoparticles with different coverage percent of CF3 groups as water and oil repellents were investigated at the water-rock and decane-rock interface using molecular dynamics simulation. Simulating a pore of rock in presence of water and decane molecules separately, resulted in liquid bridging for both of liquids. The density profiles of liquids in the pore clearly show several highly ordered layers packing of the molecules close to the rock surface. Distribution of liquid molecules around the nanoparticles is much influenced with increasing CF3 groups on the nanoparticle surface. Results show that adsorption of functionalized silica... 

Application of nanoparticles in targeted delivery and controlled drug release is recently highly attracted especially in cancer therapy. In this study with the aim of developing a novel drug vector based on metallic nanoparticles, gold nanoparticles with their unique characteristics were used to design a vector for targeted anti-cancer drug delivery to tumor. First, gold nanoparticles were chemically synthesized therough sodium citrate and sodium brohydrate reductions with average diameters of 22 and 11 nm, respectively. Then, the activated poly ethylene glycol (PEG) and activated folic acid were conjugated to the lysine-capped gold nanoparticles. Subsequently, the widely used anticancer... 

In recent years, many studies have conducted research about stem cells due to their prominent features such as proliferation and differentiation. By changing the specific parameters of the cellular micro-environment, it is possible to determine the stem cells fate and thereby use them in medical affairs. For this purpose, various devices and methods have been designeds such as microfluidic devices and scaffolds. The microfluidic devices has been especially focuced in the researchs due to their unique features, like the possibility of testing with small amounts of samples, the creation and control of low cost cellular micro-environment and low practical time. Two-dimensional scaffolds made up... 

Cancer treatment is one of the most challenging issues of recent years. Extensive researches have been conducted in various fields of medicine, pharmacy, and medical physics in this regard. Today, considering nanotechnology developments, researchers believe that full cancer treatment is possible through the use of nano-systems designed with scientific background to overcome the defects of previous methods. In this research, the main purpose is to design and synthesize multifunctional hybrid nanostructures with favorable optical and magnetic properties providing a way to combine chemotherapy and thermal treatment. Accordingly, two different structures were designed and experimentally... 

The research on the automotive brake composite materials is very extensive due to its complex formulation and the used of diverse variety of materials. While various research activities has been applied in this research group, but there are many unknown areas. This subject with the arrival of new materials, especially nanometer materials, has received increasing attention. In this study, the effect of alumina nanoparticles on the performance of automotive brake friction materials were examined. Generally, alumina (as micro particles) used as the abrasive material for many years in the formulation of composite brake pads. But, the effect of alumina on the nanometer scale hasn't been examined... 

In the present study, smart anticorrosion coatings were successfully prepared based on epoxy ester (EPE) resin and conductive nano polyaniline particles (nES). Anticorrosion behaviors of these coatings were analyzed by electrochemical techniques. Generally, this thesis consists of two main parts: the theoretical studies (1st and 2nd Chaps.) and empirical investigations (3th to 8th Chaps.).The first Chap. expresses a basic introduction about the corrosion concepts and different types of anticorrosion coating. In the second Chap. main goals and stage works of the thesis about the smart anticorrosion coatings are introduced considering literature researches. The subject of the 3th Chap. is... 

Amyloid β (Aβ) peptide is believed to be associated with the progression of Alzheimer's disease. One of the main obstacles in developments of therapeutic agents to combat progression of Alzheimer's disease, is the presence of the blood–brain barrier (BBB), which prevents the penetration of the majority of drugs. However, nanoscale objects are able to cross the BBB at low concentrations. Therefore, it is worthwhile to study the interactions of these peptides at the interface of nanomaterials. In this work we have employed molecular dynamics, and weighted histogram analysis methods in order to study the dynamic behavior and affinity of Aβ25-35 peptide on metallic surfaces of different... 

The advent of nanopore-based sensors based on resitive pulse sensing gave rise to a remarkable breakthrough in the detection and characterization of nanoscale species. The sensors can detect the species’concentration, size, and charge using the resistive pulse characteristics. Some strong correlations have been reported between the resitive pulse characteristics and the particle’s geometrical and physical properties. These correlations are commonly used to obtain information about the particles in commercial devices and research setups. The correlations, however, do not consider the simultaneous effect of influential factors such as particle shape, charge, and off-axis translocation, which... 

Selective oxidation of cyclohexene and styrene were investigated using molecular oxygen under mild conditions. Au/TiO2 and Au/Al2O3 surfaces were impregnated with three different Ionic Liquids. Supported Ionic Liquids gold nanocatalysts are particularly versatile catalysts for oxidation reaction with exceptionally high efficiency and significant selectivity.
Selective oxidation of alkenes by hexadecyl-trimethyl-ammonium bromide-stabilized gold nanorods and gold nanosphere were investigated using molecular oxygen in aqueous solution under mild conditions. Colloidal gold nanoparticles are particularly versatile catalysts for oxidation reaction with exceptionally high efficiency and... 

Today reverse osmosis (RO) is the dominant technology for desalination. Most of commercially available RO membranes are polyamide thin film composite (TFC) types which exhibit good performance. However, the major obstacle for application of polyamide TFC RO membranes is fouling which can be mitigate by surface modification.In this research, surface modification of fabricated aromatic polyamide TFC RO membranes was carried out using UV-initiated graft polymerization at different irradiation times (15, 30, 60, and 90 s) and various acrylamide concentrations (10, 20, and 30 g/L). Also, coating of membranes surface with various concentrations of TiO2 nanoparticles (10, 20, 30, and 50 ppm)... 

Nanotechnology is an efficient method suitable for fabrication and production of minimal single dimensional nanometric structures. Such materials and systems can be logically designed that lead to new and optimized biological, chemical and physical properties and characteristics due to their size. Nucleation and growth –appearance of a new phase out of an old phase – is a ubiquitous phenomenon in nature. Fundamental understanding of nanoparticles nucleation and growth mechanism allows more control on form, size and composition and allows tuning of the above said properties easily with use of different reactive conditions as a result of this ability . Nanoparticles of titania are one of... 

In this research, we focused on demonstration of features and advantages of supercritical fluids technology to formation of fine particles (nano and micro scales) from bulk materials (solid) and synthesized metal oxides nanoparticles. Therefore, using two different fluids, carbon dioxide and water, and two completely different methods, the Rapid expansion of supercritical solution and supercritical hydrothermal, were used to produce fine particles of drug (acetaminophen) and nano metal oxide (zirconium dioxide and bismuth ferrite). The summary of this research are as follows:1. The solubility of acetaminophen in SuperCritical-Carbon Dioxide (SC-CO2) with and without menthol as a cosolvent... 

In this research, immobilization method was employed to increase the thermal stability of Chondroitinase ABC I (cABC I) enzyme. In first step, magnetite nanoparticle (Fe3O4) was selected as a support and cABC I enzyme was attached via the adsorption method. The results showed that pH=6.5, temperature 15 ˚C, enzyme-to-support mass ratio 0.75, and incubation time 4.5 hr were the appropriate conditions for immobilizing cABC I enzyme on Fe3O4 nanoparticle. It was also found that the optimum pH for free and immobilized enzymes was 7.6 and 8.0, respectively. The maximum activity of free enzyme was obtained at 25 ˚C, whereas the activity of immobilized enzyme was almost constant in the temperature... 

A biocompatible ferrofluid have been prepared by co-precipitation of FeCl2.4H2O and FeCl3.6H2O under ultrasonic irradiation and with NaOH as alkaline agent. Also cystein was used as capping agent in the solution. Magnetic properties of the produced ferrofluid then determined by VSM test and magnetite nanoparticles were characterized by XRD and TEM techniques. Results indicate the presence of a biocompatible superparamagnetic ferrofluid including magnetite nanoparticles with particle size ranging under 15 nm. The effect of ultrasonic irradiation on presence of a sharp particle size distribution then denoted by comparing the condition with production without ultrasonic irradiation  

In this thesis, proteinnanoparticle interactions have been studied using Molecular Dynamics simulation. sT fN, is the studied protein in this work. It is one of the most important proteins in the blood fluid. In this work, nanoparticle has been modeled as a surface; because the radius of gyration of sT fN is less than 3nm, so when it is near an enough big nanoparticle (100200 nm), nanoparticle seems as a surface from the view of protein. The surface of nanoparticle consists of sodium ions. Surface of nanoparticle, has been modeled using two types of surface:flat surface and nonflat surface. Protein interaction with surface, has been studied in two different initial orientations with respect... 

Pesticides are broadly applied in croplands, glasshouses, and orchards in order to increase agricultural products and their quality. Among the variety of pesticides, organophosphorus pesticides (OPs), possessing high insecticidal activity, acute toxicity and relatively short environmental persistence, have been widely used for pest control in agriculture. However, this effect might lead to adverse health impacts or death for mammals and humans. Thus, even at trace levels, it is of great importance to develop a simple, sensitive, inexpensive and real-time detection method for monitoring the levels of pesticides in the environment, foodstuffs and biological samples. The integration of metallic...