Sharif Digital Repository

In this research, in order to investigate the effect of zeolites nanoparticles on the separation performance of a liquid membrane, a TEG/Nano Na-Y was developed. To do this, a high yield nano zeolite Na-Y was synthesized using mid-synthesis addition method . The synthesized samples were characterized by XRD, FT-IR, and SEM (EDX) instrumental techniques. A supported liquid membrane was prepared by impregnating a porous hydrophilic PVDF support with TEG and nano zeolite Na-Y. Permeances of single gas components of CO2, N2 and O2 were carried out at different pressures of 0.8, 1.8 and 3.7 bar. The single gases permeances were found to be: CO2 > N2 > O2. The results were shown that higher weight... 

The present work emphasizes on hydrogen resistance- sensing properties of WO3 films prepared by Sol-gel routs. The sol-gel is a simple and low cost rout which makes film with high homogeneity and low processing temperature .To improve Hydrogen sensing we modified WO3 films with Pd catalysts by Sol-gel and Electroless methods. AFM , EDX, SEM , XPS , XRD , were applied to analyze structure, morphology and Chemical composition of the fabricated thin films. We measured resistance sensing behavior of prepared films in exposure to different concentration of Hydrogen. All the films were tested under the same conditions. We measured resistance sensing in exposure to concentration below 10000 ppm... 

Highly active unsupported MoO3 and (Co) MoO3 catalysts were synthesized utilizing the solution combustion method where the Ammonium molybdate powder and an organic additive were used as precursors. Different organic materials including Ethylene Diamin Tetra-acetic acid (EDTA), Polyethylene Glycol 200 (PEG 200), Sorbitol and Urea were used as additive in order to investigate the effect of additive structure on morphology and particle size of products. Also various reaction parameters such as the additive/Mo molar ratio, concentration of metal ion in solution, pH of the reaction and temperature of the synthesis media were changed to study effects on product morphology and size. Outcomes were... 

Red grape skin has a lot of antioxidant that called Anthocyanins. In this research this material has been studied and amount of extraction of them have been studied by changing the operational parameter and particle size in taguchi procedure. Pressurized liquid extraction (PLE) was used to extract Anthocyanins from Dried Red Grape Skin (DRGS) with acidified Ethanol solvent (1 %( v/v) of HCl) in 90-120°C, 10-40 bar, and 30 min extraction time. In this study, effect of particle size distribution of DRGS was considered and the results showed that with increasing the temperature (from 90 to 120 °C in 10 °C increments) and decreasing the pressure and particle size the extraction of Anthocyanins... 

Doping metal or semiconductor nanoparticles in transparent matrix have attracted much attention for practical application in recent years. From fundamental veiw point, limiting the charge carriers and exitons in nanometric scales resulted in new quantum phenomena. In this context, transparent films containing metal nanoparticles shows an absorption peak in visible region of spectrom. Thus, by choosing an appropriate metal and controlling the size and concentration of particles in corresponding matrix, we can provide coatings with a wide rang of colors. Furthermore, thin films containing metal or metal oxide nanoparticles had been considered as nanostructure materials in research and... 

In the first part of this work, citric acid monomer was selected to produce dendrimer through the divergent method using logical conditions (for controlling its functional groups) on the base of poly (ethylene glycol) as the core. Triblock copolymers (ABA-type) of citric acid and poly (ethylene glycol) (PCA-PEG-PCA) as biocompatible compounds were synthesized in four different molecular weights and applied as nanocarriers. The structure definition of the molecules and nanoparticles were carried out using different spectroscopy methods. Diameter of the synthesized copolymers was investigated using dynamic light scattering (DLS) experiments and transmission electron microscopy (TEM) and it was... 

Formation of nanoparticles by the gas phase condensation process is one of the most promising methods for the nanoparticles synthesis. Finding the correlations between adjustable parameters of the process and nanoparticles properties depends on how parameters affect the mechanism of nucleation and growth. The use of classical nucleation theory at nanoscale leads to unacceptable results; hence, approaches such as molecular dynamic simulation (MD) have been proposed to investigate the mechanism of nucleation and growth at atomic scale. In the present work, the formation of iron clusters from a supersaturated gas phase was investigated via molecular dynamics simulation. For thermalization of... 

The purpose of this research project was to improve the performance of TEG liquid membrane in separation of gas mixtures by adding zeolite LTA nanoparticles. Therefore, the NaA zeolite particles with nano size were synthesized with hydrothermal method at optimized condition. The supported liquid membrane with hydrophilic PVDF membrane and triethylene Glycol (TEG) was prepared in two different conditions. In the first one, the pores of the supporting membrane were filled with triethylene Glycol, whereas in the second one the pores were filled with the mixture of triethylene Glycol along with the 5 wt% and 10 wt% zeolite nanoparticles. The performances of prepared membranes were investigated... 

This project reports an experimental work on the convection heat transfer of nanofluids, made of -AL2O3 nanoparticles and de-ionized water, flowing through a copper tube in the laminar flow regime. The results showed considerable enhancement of convective heat transfer using the nanofluids. The enhancement was particularly significant in the entrance region, and was much higher than that solely due to the enhancement on thermal conduction. It was also shown that the classical Seider and Tate equation failed to predict the heat transfer behavior of nanofluids. Possible reasons for the enhancement were discussed. Migration of nanoparticles and the resulting disturbance of the boundary layer... 

In this research we focus on synthesis and analysis of metal and metal oxide nanoparticles and their photocatalytic activity. At the beginning a high current DC power supply and a reactor for the electrical arc discharge process designed and implemented. Several nanoparticles such as tungsten oxide, zinc oxide, silver and gold have synthesized by this method in deionized water, deionized water including surfactants and stabilizers and analyzed. Several characterization techniques such as X-ray diffraction (XRD), dynamic light scattering (DLS) X-ray photoelectron spectroscopy (XPS), BET, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis spectroscopy have... 

Superparamagnetic iron oxide nanoparticles (SPION) with proper surface coatings are increasingly being evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance imaging, transfection, and cell/protein separation. Since the particles with various sizes exhibit different flow rates in the same environment (same capillary size), it is essential to use particles of a desirable size for targeted drug delivery and imaging. Particles of different sizes may be exposed to different viscosities and behave differently, particularly with regard to their velocities as they move through capillaries. In the present work, SPION with different size, purity, shape and... 

Recent advances suggest that many of the issues involving in improving water quality could be solved by using nano particles. Aquifer and groundwater remediation are also critical issues. Becoming more important as water supplies steadily decrease and demand continues to increase. Although some of the remediation technologies available today are , they are costly and time-consuming, especially pump and treat methods. A wide range of nano particles have been used for the removal of organic and inorganic contaminants. In the first part of this work, zero-valent Iron nano particles was synthesized and was covered with nickel as catalyst. Diameter of the synthesized nano particles was... 

ZnFe2O4 nanoparticles have been successfully prepared through a controlled microwave–assisted co-precipitation as well as conventional co-precipitation. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were used for the structural, morphological and magnetic investigation of the product. Average particle size was obtained as 12 nm from XRD. Catalytic activity of ZnFe2O4 nanopowder for O-acylation of alcohol and phenol has been investigated. A trace amount of ZnFe2O4 has been effectively used as a nanocatalyst for the acylation of alcohol and phenol in acetic anhydride.

 

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... 

Adding solid lubricant particles such as PTFE, Graphite and MoS2, has major influence on electroless composite nickel coatings in order to make low friction surfaces. Among these lubricants, MoS2 has attracted great attention due to its highest stability under wearing condition. In this work Ni-P-MoS2 composite coatings using MoS2 nano-particles have been made and in the next step, we evaluated tribological properties of these coatings. For exploring these coatings different experiments were utilized, like Scanning Electron Microscope study (SEM), chemical composition analysis exploiting AAS and XRF method, and thickness measurements. Two kinds of surfactants, CTAB and PVP, have been applied... 

In recent decade energy crisis causes research on luminescent devises gains special importance. Particularly, hybrid LEDs (organic- nanocrystal) have been studied by a number of researches due to their advantages. Easy fabrication and narrow spectrum of radiation are mentioned as the most important benefits. The emissive layer is the most important part in these diodes which made of semiconductor nanoparticles. There are a variety of chemical methods for synthesis of semiconductor nanoparticles. We focus on aqueous method for nanoparticles synthesis because of its advantages. Alloyed semiconductor nanoparticles of ZnxCd1-xS were selected for this research work. The manifest features of the... 

Electrical arc discharge in ambient air, vacuum, reactive gas and other environment is an appropriate method for synthesis of different nanostructures. This method can provide stable and ultra pure nanostructures with diverse applications. In this research we focus on synthesis and analysis of titanium nitride nanoparticles in liquid nitrogen(lack of oxygen)by Electrical arc discharge . At the beginning a reactor for the electrical arc discharge process designed and implemented. Titanium nanoparticles have synthesis by this method analyzed. Several characterization techniques such as X-ray diffraction (XRD), dynamic light scattering (DLS), X-ray photo electron spectroscopy (XPS), scanning... 

Recently, diamond nanoparticles have attracted interest for biomedical applications such as drug delivery, targeted cancer therapies, fabrication of tissue scaffolds and biosensors. In the present work, elecrophoretic deposition (EPD) of nanodiamond-bioactive glass-alginate nanocomposite was studied. In vitro bioactivity and biocompatibility of the nanocomposite were evaluated in simulated body fluid (SBF) and by MTT assay. The EPD process was performed under different conditions in order to obtain a uniform coating on the surface of 316L stainless steel substrate. The stability of the suspension was determined via optical sedimentation method and zeta potential analysis. It was found that... 

This research is focused on fabrication of TiO2 layers by electrophoretic deposition (EPD) for application as photoanode in Dye Sensitized Solar Cell (DSC). DSCs are third generation of solar cells, also known as the Grätzel cell, after its inventor Michael Grätzel. A DSC is composed of a porous layer of wide band gap semiconductor such as TiO2 and ZnO, covered with a molecular dye that absorbs sunlight, and a counter electrode contacted by a liquid redox electrolyte. Dye Sensitized semiconductor (photoanode) has important role in conversion of photon to electricity. To achieve higher efficiency, preparation of photoanode with high surface area resulted to enough dye adsorption is necessary.... 

Successful formulation development for poor water soluble drugs is a critical, long-standing and challengeable problem in cancer treatment. One of the methods for transporting low-soluble drugs is using nanoparticles which are able to pass through capillary walls of tumor tissues due to their small size. An example of the nanoparticles is micelle systems. Functionalized β-cyclodextrin (β-CD) by hyper branched polyglycerol (HPG) can dissolve low-soluble compounds. This polymer can be used in preparing micelles. In this project, β-cyclodextrin (β-CD) by anionic reactions is initiator for polymerization of glycidol monomer. Hydrophobic cavity of the β-cyclodextrin (β-CD) in placing the phenyl...