Sharif Digital Repository

The purpose of this project is to investigate the production of nano-micro metallic particles—of different elements—with different characteristics in size and optical property by employing a pulsed laser ablation processes in liquid medium. In this study, the means by which we build the laser, the experimental arrangement of the pulsed laser ablation process, the measurement of the absorption spectrum of generated nano-micro particles as well as the size of the particles are discussed.
To satiate this aim, we have expressed the manner of constructing the Nd:YAG laser, the power supply circuits, along with its optics. This laser has some advantages such as high energy ~700mj, good... 

Study of the recycling of acidic sludge waste produced from oil refineries and its application in road pavements is the one of the most important issues. Disposal of this sludge has always put the nature at risk. In this research, preliminary NPS bitumen was derived through neutralization and processes. NPS was modified by some thermoplastic elastomers such as SEBS, SBS, EVA, … and SBR and NBR rubbers. Also as a ionic and surface modified organoclay, C15A was used in three different weight percent. Rheological and performance behavior of pure bitumen and modified ones was studied using of standard tests for simulating traffic load. Behavior evaluation tests was included dynamic frequency... 

The theory of mass transfer accompanied by chemical reaction for gas-liquid systems was used to measure the specific interfacial area and mass transfer coefficient in a two impinging jets reactor (TIJR) in the presence of γ-Al_2 O_3 nanoparticles.The absorption of oxygen in sulfite solutions used for the determination of mass transfer characteristics. First 3 liters of nanofluids were prepared at concentration of 1 w% then diluted To produce 10 Liters of nanofluids containing 0.3 w%. The stability of this nanofluid was determined using uv-vis to be less more than 95% in the first 3 hours. The influence of weight percent of nanoparticles (0, 0.05, 0.1, 0.15, 0.2, 0.3) on the specific... 

In the first part of this thesis, the application of metal oxide nanoparticles in oxidative degradation of methylene blue is discussed. Nanoparticles of manganese tungstate (MnWO4) were prepared via an impregnation method using Mn(NO3)2.4H2O and WO3 as a source of Mn and W, respectively. The morphology of the manganese tungstate nanoparticles was studied in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). MnWO4 nanoparticles showed severe catalytic performance for the degradation of organic dye (methylene blue) in the presence of tertiary-butyl hydrogen peroxide, TBHP, as the oxidant at room temperature in water. Mn doped ZnO... 

Particle retention and clearance is a major concern in the treatment of pulmonary diseases. Inhaled materials into the nasal and lung airways include gases/vapors, liquid droplets and soluble/insoluble particulate matter which can be toxic or therapeutic (or both). For example, nanoparticles (NPs), as part of nanomedicine, are now being used as drug carriers for passive and active targeting of solid tumors and inflamed tissue. However, natural and especially manmade NPs can also be harmful, such as carbon nanotubes (CNTs), asbestos fibers and ambient toxic pollutants, based on epidemiological and pathological studies of occupational and environmental exposures. In fact, ultrafine particles... 

Nowadays, silicon based devices especially carbon nanotubes received lots of attentions and advancement from researchers and industries. Because of amazing electrical and mechanical properties and wide range of applications, CNTs are received a lot of attention from nanoelectronics experts. There are lots of CNT growth methods such as: Arc Discharge, Laser Ablation, Surface Decomposition, CVD and PECVD.
In this thesis, we are going to use PECVD method to synthesis CNT. A typical PECVD system includes two parallel electrodes that have been packed in vacuum chamber and gases like argon, hydrogen and NH3 are introduced to chamber as a reactant gas.
In this thesis, firs we had fixed... 

Syntheses of coats including nickel nano-particles by electrodeposition have been
investigated for over 10 years. A method of testing according to surface reply was chosen
to reveal the effect of each pulse parameters (including duty cycle, frequency, average
current density, off time (toff) and on time (ton)) and the effect of saccharin concentration
on electroplating cathode efficiency, nanostructure. Pulse electroplating test of nickel was
composed by 30 tests. Pulse electroplating with relatively high peak current density was
employed and saccharine was added to increase deposition and rate of nickel nucleation on
surface. According to the results of cathode... 

Foam injection for enhanced oil recovery is concerned by petroleum engineers because it decreases adverse effects of fingering and gravity segregation caused by the injected fluid .Obviously foam stability is an important factor in the efficiency of this process. So investigating it is an imperative. One of the ways that less studied and can improve foam stability is using of nanoparticles. In this project effect of nanoparticles on foam stability and displacement mechanism during foam flooding has been discussed.
Study consisted of two sets of experiments. In the first part, the static foam stability in the presence of silica nanoparticles has been investigated. Also influence of... 

Fines migration due to their severe problems during oil production must be controlled. They cause the productivity decline due to their deposition near the well bore. Recently, application of nanotechnology in fine migration control has been much attended in both experimental and field case investigations. The main goal of the present study is to find out the ability and different effects of Nano particles (NPs) such as concentration, types and even the magnetic sensitivity to retain fines migration. In order for this, two groups of tests were conducted by engineered porous media. In this study, for the first time, an experimental setup was designed and constructed to investigate the control... 

Joining of yttria-stabilized zirconia (YSZ) to stainless steel (SS) is considered for various applications such as solid oxide fuel cells, thermal barrier coatings, and medical implants. In the present work, a series of brazing pastes utilizing silver and nickel nanoparticles (~80 nm) mixed with carboxymethyl cellulose as the organic phase were developed to join 5YSZ to 420 SS. The effects of processing parameters such as time and temperature of brazing and the composition of the paste on the microstructure of the joint and its mechanical strength were studied. The mechanism of interface formation was elaborated by scanning electron microscopy (SEM) and electron probe micro analyzer (EPMA).... 

In current project, high purity nanoparticles were synthesized by use of Electromagnetic Levitation Melting Gas Condensation (ELM-GC) method. In this case high purity aluminum samples were melted by this method to a temperature of 1683 0C in a silica tube. High purity argon and helium gases were employed as carrier gases and cooling agents. To study particle size, morphology, and purity of obtained nanoparticles, Field Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD), Dynamics Light Scattering (DLS), and ADS analysis were employed. The FE-SEM and DLS tests confirmed narrow size distribute of spherical shape pure aluminum nanoparticles under both inert gases. The... 

One of the most well-established methods of increasing oil production rate from existing fields is infill drilling. However, drilling these depleted reservoirs with conventional high density drilling fluids may cause formationdamage problems and subsequently reduce the expected production rate. To overcome these technical problems, the use of lightweight aphron based fluids isincreasing rapidly in the petroleum industry. Rheological and fluid loss performance of aphron based drilling fluids can be improved in the presence of nanoparticles; however, very limited information is available in this field. Moreover, a thorough knowledge about the hydrodynamic flow behavior of drilling fluids... 

Immobilization of β-D-galactosidase represents an important approach for development of lactose hydrolysis technology.Chitosan proved to be an excellent carrier for β-Dgalactosidase immobilization, by both covalent binding and sol-gel entrapment combined with adsorption. Among different preparation methods of chitosan support particles for covalent binding, emulsion cross-linking was the most efficient, producing narrow-sized microspheres, without aggregation.The best process parameters of β-D-galactosidase immobilization by covalent coupling on chitosan microspheres were found as 3% glutaraldehyde cross-linker concentration, enzyme loading of 27 mg protein/g dry support, 6 h reaction time,... 

By using Mie theory and experimental data for complex refractive index of Au and Ag nanoparticles, the scattering and absorption efficiency of these nanoparticles in silicon medium (crystalline, Polycrystalline and amorphous silicon) was investigated. It was shown that Ag and Au nanoparticles can be used for confine the light, in desired wavelength band, inside the solar cell.The optimum nanoparticle size for using in this kind of solar cells was about 70-80 nm. In amorphous silicon confined photons cannot participate in electron-hole generation so the application of these metal nanoparticles in this kind of solar cells cannot be useful. Also the complex refractive index for equivalent... 

The purpose of this research is the synthesis of nanoparticles using micro fluid glass.The microfluidic glassy building is studied. Glass microfluidic microchannels making hydrophobic the continuing experiments carried out so that the water droplets in the organic phase and at the end of nanoparticles should be synthesized. Tests hydrophobic microchannels and water droplets in the organic phase was formed. In order to ensure an escape water contact angle and FTIR micro-channel test is taken and to avoid the droplets merged with each of surfactant SDS was used. In the end, DLS and FESEM nanoparticles synthesized using the tests have been evaluated and the concentrations of reactants and flow... 

Nanoparticles can be applied as chemical agent in enhnaced oil recovery like surfactants and polymers. One of nanoparticles usefull capabilities is modification of their surface. This research investigates this capabilty of nanoparticles in enhanced oil recovery. Surface modification of nanoparticles with both agents can bring new abilities to these materials. Here surface of silica nanoparticles is modified by hydrophilic agent comprising PEG groups, hydrophobic agent comprising propyl group and both agents. FT-IR tests showed that grafting of modifiyng agents on surface of nanoparticles is well done. To investigate effect of nanoparticles surface modification on nanoparticles capability in... 

Bismuth Vanadate (BiVO4) nanoparticles were prepared from two different precursors by precipitation method. The samples were characterized by Fourier transformed infrared (FT-IR), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and BET. The photocatalytic activities were examined by degradation of Acid Blue 92 under visible light. The results revealed that all the BiVO4 samples were in a monoclinic phase in nano range. The photocatalytic activity of BiVO4 depend on the calcination temperature and the concentration of photocatalyst. The photocatalytic activity increases with the amount of catalyst loading and decreases with increasing the... 

The purpose of this study is to assess the inhibitory effects of an appropriate nanoparticles loaded with gallic acid on the fibrillation of alpha-synuclein. Alpha-synuclein is a major component of protein plaques in synucleinopathies, particularly Parkinson’s disease. Gallic acid (GA, 3,4,5-trihydroxy benzoic acid) is a well–known small molecule which can inhibit the formation of α-synuclein fibrils. For the process of fibrillation, purified protein was incubated at 37◦C and pH 7.2. Fibrillation was analyzed by the standard fibril methods.after that investigated fabricating of gallic acid trapped in the chitosan nanoparticles and gallic acid loaded in chitosan –coated mesoporous silica... 

In this study Ni-P-Al2O3-SiO2 nano composite coating developed on aluminium alloy 6061 using electroless method. Due to oxidation of aluminium, a double zincate pretreatment performed to obtain proper adhesion of coating on substrate. Effect of solution temperature and heat treatment on thickness and property of nano composite coating was studied. Furthermore, effect of concentration of nano particles in electroless solution on thickness, morphology, micro hardness, wear behavior, corrosion resistance and particle content in coating were investigated. Field emission scanning electron microscopy (FESEM, Hitachi S-4160) with energy dispersive spectroscopy (EDS) was used to evaluate morphology...