Sharif Digital Repository

Zinc oxide thin films due to special specification and properties have variable application in different industries. Recently because of wide application of zinc oxide doped SiO2 in optoelectronics and sensors, lots of investigation have been focus on it. Meanwhile due to the SiO2 hydrophilic properties, doping of ZnO with SiO2 can improve self-cleaning properties zinc oxide membrane.It this project zinc oxide and ZnO doped SiO2 thin films with different composition were made by sol-gel and dip-coating process used for coating of mentioned sol over the quartz surface(15*25 mm). At first point different sol with different components was mixed with each other to make composite films but due to... 

Electrocodeposition of Ni-TiO2 nanocomposite single layers and Ni-TiO2/TiO2 multilayers from Watts bath containing TiO2 sol has been carried out on copper substrate. Cyclic voltammetry and chronoamperometry techniques were applied to study the influence of nickel sulfate and TiO2 sol concentrations on the electrochemical behavior of Ni-TiO2 deposition by direct current. The results clearly showed that at lower sulfate concentrations, the electrodepostion is a diffusion controlled process. Besides, the nucleation mechanism of the nanocomposites at low overpotentials followed the progressive system while at higher overpotentials, it was found to be instantaneous with three-dimensional growth... 

In photocatalitic activity of titana an effective approach to achieve high charge separation efficiency and high level of sensitivity under visible light is coupling it with another semiconductor with smaller band gap and appropriate banding energy structure. achieving all mentioned above, we used bilayer structure and coupled TiO2 with hematite which its small band gap(Eg ~ 2.1 ev) is sensitive to visible light. Bilayer systems of TiO2/Fe2O3 , Fe2O3/TiO2 were fabricated by sol-gel process and variable parameter was upper layer thickness. The layers were deposited on glass substrate via sol-gel process. The upper layers were prepared in different thicknesses in two ways. First, they... 

In this research, TiO2 nano-particles were electrophoretically deposited on the FTO glass to produce self-cleaning property. Two type of suspensions with different TiO2 nano-powders were used. Merck and fabricated by sol-gel route, TiO2 nano-powders were utilized in suspensions and Conductivity, pH and zeta potential of suspensions were determined. Electrophoretic deposition of two kind of suspensions was performed in different voltages of 10, 30 and 60V (for 10s) and room temperature. TiO2 coatings were sintered in 450oC for 1 hour. The phase transformation of TiO2 films were measured using XRD. Morphology, average particle size and thickness of TiO2 films were analyzed using FESEM... 

In this study, TiO2-SiO2 nanocomposite films with different amount of SiO2 were prepared by sol-gel process and were coated onto stainless steel 316L. The effect of addition of various amounts of SiO2 in the precursor solution on the structure, morphology, photocatalysis, photo-generated hydrophilicity, self-cleaning property and mechanical properties of TiO2 thin films and corrosion behavior of AISI 316L stainless steel substrate, was investigated. For this purpose, X-ray diffraction, Fourier transform infrared spectroscopy, water contact angle measurements, UV spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, depth-sensing indentation technique supporting... 

Transparent coatings with self-cleaning property in visible light spectrum, UV radiation resistance and antimicrobial are highly desirable. Titanium dioxide (TiO2) is used in this research has been widely studied as an efficient photocatalyst by researchers. In this research enhanced visible-light photocatalytic activity is gained with N and Ag co-doped titania. All samples were annealed at 450℃. Finally AgI was loaded TiO2 coating and the results were investigated. Peaks of XRD pattern wereattributed to different diffraction planes of anatase TiO2. Morphology of coatings were analyzed with using FE-SEM. Nano granis size of TiO2 and AgI loaded TiO2 were observed in FE-SEMimages. Nitrogen... 

composite membranes with PVC as the matrix, Alumina nanoparticles as filler and PVP as additives, were optimized and built. First, the interaction of PVC, PVP and alumina particles on the membrane structure and its performance was investigated by using Design expert software. The membranes which the software proposed were prepared and pure water permeability and flux decline tests were done according to evaluate the membranes performance in membrane bioreactor (MBR). And the results were imported in software and material effects on the performance of each membrane were analyzed. In order to better assess the efficiency and effectiveness of alumina nanoparticles on membrane, different values... 

All the biological diagnostic devices that are introduced to the consumers, must meet WHO criteria. Some of these criteria include being affordable, sensitive and deliverable to the user. In the last twenty years, there have been lots of efforts to use microfluidic devices for biological assay. Due to their expensive price and requirement of complex equipment for their fabrication, polymer-based microfluidic devices have not been able to be used in developing countries. It is to be hoped that introduction of paper for fabrication of microfluidic devices could make microfluidic devices meet WHO criteria. μPADs are divided into well-based and channel-based devices. In the present work, both... 

Surface modification is an important property of nano particles. In this project surface of silica nano particles modified with hydrophobic and hydrophilic groups to imrprove surface activity of nano particles. Purpose of this project is to study surface activity of surface modified silica nano particles in different temperatures from 20 to 70 degree centigrade. Also effect of salt and time on the surface activity is studied. At first nano particles modified just with haydrophobic groups and then just with hydrophilic groups (hydrophobic and hydrophilic nano particles) and after that, the surface modification done with both hyadrophilic and hydrophobic groups (amphiphilic nanoparticles).... 

As many oil fields are reaching their final stage of production, new technologies are required in order to maintain production and increase recovery of hydrocarbons. Among these techniques of enhanced oil recovery (EOR), chemical injection method focuses on increasing the effectiveness of waterflooding. Due to the relatively high costs and considerable adsorption on the rock formations, this method is no longer used. In Recent years nanofluids (nanoparticles dispersed in brine) have been used as a cheap, efficient and environmentally friendly alternative more than any other chemicals. It has been stated that the Smart Water method and enhanced oil recovery by SiO2 nanoparticles are effective...