Sharif Digital Repository

In this thesis, we aim to study the elastic-plastic behavior of short fiber reinforced composites experimentally and analytically. The experimental investigation is applied to glass fiber-polypropylene composites (PP/GF). The samples are produced by injection process with maximum temperature of 190C. Fibers are randomly oriented in this procedure of fabrication. The samples are tested in tension, and the mechanical strength is measured by changes in fiber content. The Young's modulus is also investigated in these experiments.Also in this thesis, an analytical model for calculation of Young’s modulus of fiber reinforced composite materials is proposed. In this analysis a displacement field is... 

Green chemistry seeks to reduce or eliminate the use of hazardous substances in the chemical industry through the development of new products and processes .The replacement of harmful, widely used solvents and reagents is a key part of this approach. Supercritical fluid such as CO2 or water are good solvent for replaceement Exchange reactions involving the displacement of hydrogen bonded to carbon by deuterium are of interest in a broad variety of disciplines, such as the preparative chemistry of isotopically labeled materials, fundamental studies of carbonehydrogen bond activation processes, and studies of the nature of catalysts. The low cost of water and its environmental friendliness... 

In network science, link prediction is one of the essential tasks that has been neglected. One important application of link prediction in telecommunication networks is analyzing the user's consumption pattern to provide better service. This project aims to predict future links with applications to call data using the users' call history. In previous research, there are two main approaches: 1) heuristic-based approach, and 2) deep-learning-based approach, such as graph neural networks. These methods are mainly used for processing static graphs, and therefore, we cannot generalize them to dynamic graphs. But there are many graphs which are dynamic in nature. For instance, call data records... 

Cleanrooms have been widely used in many industries. The main goal in designing a clean space is to control the level of particles concentration. As a result, introduction, generation, and retention of airborne particles inside the environment need to be minimized. In this research, the effects of main parameters on the generation and deposition of particles through cleanrooms have been numerically investigated. At first, the role of geometric features of swirl diffusers on the induction effect and the resultant air mixing has been evaluated. Using parametric study approach, the diffuser geometry has been optimized and sensitivity of its optimum features to the airflow rate has been... 

Nitrate can be used as an oxidant in a cathode chamber of microbial fuel cell. Nitrate is known to be a pollutant of water particularly underground water and is considered a carcinogen of water. Nitrate was used in the cathode chamber of a microbial fuel cell as an oxidant that lead to simultaneous generation of electricity, removal of organic matter in anode, and removal of nitrate in the cathode. Using nitrate generated a voltage of 151 mV with an external resistance of 1000Ω. The maximum power density achieved was 1.375 mW/m2 with an external resistance of 800Ω. Seven days after the cell became operational and without the presence of a catalyst, the amount of COD had decreased by 25... 

Silica nanoparticles is one of the most important mineral particles. In this study, Sodium silicate, Sulfuric acid and Sodium aluminate is used in order to synthesis of the modified Silica nanoparticles. The effects of temperature, reaction time and the molar ratio of regents were tested and optimized. Synthesized nanoparticles were characterized by use of XRD, FT-IR and SEM techniques. The results show that by controlling the reaction conditions, nanoparticles with an average size of 26.2 nm is obtained. The increase of temperature and reaction time alters the structure of the particles of amorphous state to a crystalline needles. The particle surface modification process was performed by... 

ZnO nano particles and mordnite zeolite nano particles were prepared by precipitation method and hydrothermal method,respectively. The influence of solvent and surfactant in ZnO nano particles synthesis were studied to reform the structure of nano particles.These nano particles were based on different supports to improve and enhance their photocatalytic activities. Synthesized catalysts characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform-infra red spectra (FTIR), UV-Vis spectroscopy and BET techniques. To investigated photocatalytic activity of the synthesized catalysts under UV irradiation, they were used to degradation bio-environmental... 

In this work we intend toeconomically recovery of residual from terephthalic acid production unit in the Tondgooyan petrochemical company. Major component of this residual is catalysts, benzoic acid and amount of terephthalic acid product. Catalysts contains of cobalt, manganese and bromide which recycled by water extraction. Effective variable on extraction process is dilution ratio of water to residue, extraction temperature and time. Optimum condition of catalystsrecovery consist of dilution ratio of water to residue 6:1, extraction temperature and time is 45 C° and 40 minrespectively. Recovery yield of cobalt, manganese and bromide in this optimum condition is 91.21, 91.89 and 92.53... 

Natural products obtained from plant extract are well known as a valuable source for research and assessments which eventuates to the discovery of some compounds possessing biological and pharmacological properties. Our aims have been to investigate and identify some natural products having the ability to effect on protein misfolding. In neurodegenerative disorders, like Alzheimer’s and Parkinson’s, a protein or a peptide undergoes conformational changes, and consequently the protein transform to fibrils coined amyloid. To determine the effective anti-amyloid compounds in natural products, Borage leaves was chosen. The plant extract was extracted using soxhlet and applied to hen white egg... 

Trolling mode atomic force microscope (TR-AFM) significantly reduces the hydrodynamic drag generated during operation in liquid environments. This is achieved by utilizing a long nanoneedle and keeping the cantilever out of liquid. In this research, a continuous mathematical model is developed to study TR-AFM dynamics near a sample submerged in the liquid. Effects of cantilever torsion, nanoneedle flexibility, and liquid-nanoneedle interactions are considered in the model. The finite element model of the TR-AFM resonator considering the effects of fluid and nanoneedle flexibility is presented in this research, for the first time. The model is verified by ABAQUS software. The effect of... 

The petroleum industry is one of the technological applications which more platinum-group metals (PGM) employs. Therefore, the recovery of the PGMs from the waste catalysts of petroleum industry could be an important source to obtain these precious metals, with economic and environmental consequences.
In this work, the recovery of platinum and palladium from petroleum catalysts has been studied using waste RG-582 and LD-265 catalysts. Both catalyst were characterized through XRF, XRD and AAS. Aqua regia used as a leaching agent and The effect of dissolution temperature and time, liquid/ solid ratio (L/S), size of particles and elimination of coke was investigated. Under optimized... 

In the first chapter of the thesis the synthesis of indolylsulfanyl acetamide derivatives using thio-oxindoles has been reported. The properties of this reaction are, one-pot, without using catalysts, acetonitrile solvent and the raw material is available. This reaction has high yield and seperation products is done using column chromatography. Indole derivatives has various medicinal and biological properties and synthetic products in this project has indole ring, aldehyde and amide functional groups. In the second chapter of the thesis, a new magnetic nanocatalyst has been designed. The magnetic nanoparticles were coated with triazole ligand and then palladium (II) ion was loaded onto the...