Sharif Digital Repository

Multiwall carbon nanotubes (MWCNTs) and carbon black (CB) reinforced polypropylene/polyamide6 (75/25) nanocomposites were prepared by melt compounding approach. Polypropylene grafted with maleic anhydride (PP-g-MA) was used as compatibilizer. Different amount of fillers were introduced into the polymer blends. The morphology, mechanical, rheological properties and crystallization behavior of the composites were investigated. Scanning electron microscopy was employed to study the microstructure. Differential scanning calorimetry (DSC) results showed that the addition of MWNT or CB to PP/PA6 blend resultes increase in crystallinity degree of PA6. The fillers were found to be located... 

In this research UHMWPE/CB nanocomposites were prepared via in situ polymerization using Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and carbon black were used as supports of catalyst. TiCl4 accompanied by triisobutyl aluminum and diisobutyl phthalate (DIBP) constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Then, structural, thermal and mechanical properties of produced nanocomposites with different CB content were evaluated by SEM, DSC, TGA, DMTA and tensile tests. Scanning Electron Microscopy (SEM) images also certified very good dispersion of CBs throughout PE matrix.... 

In this study, with respect to previous projects, we focused on size reduction of hollow and endohedral fullerenes research reactors. For this reason, we set up two reactors having 1/2 and 3 liters volumes and then such parameters as pressure, reactor temperature, arc duration time, arc time interval and the working electrical current through the electrodes circuit, in both reactors were optimized. The reactors, 3- and 1/2-liter reactors were of types of horizontal and vertical, respectively. In this project spatial angle between two electrodes were also found as effective variable on fullerenes yield in the 3-liters arc reactor for the first time. We found that upon correction of the... 

At today’s crowded world, the importance of automobile transportation is obvious for all. Due to energy crisis and air pollution problems, designing and manufacturing high-performance and low emission engines is very important. Because of high efficiency and low fuel consumption, diesel engines have attracted more attention. In addition to the mentioned advantages, diesel engine’s nitrogen oxide and particulate matter emissions are very high. So to limit these pollutants, strict standards was legislated by different countries and nations. Recently in the field of diesel engines emission reduction, low temperature combustion concept is proposed that can reduce nitrogen oxide and particulate... 

Today, the importance of transportation and motor vehicles is crystal clear for everyone. On the other hand, energy crisis and the emissions of these vehicles are two fundamental problems of internal combustion motors. On account of this, the diesel vehicles have absorbed researchers’ attentions due to their higher efficiency and low fuel consumption.Due to high diesel vehicle efficiency, it is tried to substitute gasoline vehicles with these vehicles. In addition, the unrecyclable nature of fossil fuels has led to more attention to renewable energies such as biofuels. A lot of kinds of herbal oils have identical characteristics with diesel fuel.In this research, the combustion of Rapeseed... 

In this study, the performance of the Moss-Brooks semi-empirical model in estimating soot for six different diffusion flames with methane, ethylene, and kerosene fuels in laminar and turbulent regimes has been investigated. The results show that the model with the default constants in the laminar ethylene flame has relatively acceptable performance, but in the turbulent ethylene flame as well as the laminar and turbulent flames of methane, has a significant error. In this regard, inspired by past research and performing sensitivity analysis, the constants of oxidation and coagulation sub-models were reviewed and Improved. The results of soot volume fraction were evaluated for values of 0.015... 

In this thesis, reactivity controlled compression ignition (RCCI) combustion fueled by diesel and natural gas is experimentally and numerically investigated. Natural gas as a fuel with low reactivity is injected into the intake manifold, and diesel as a fuel with high reactivity is injected directly into the combustion chamber. One of the main goals of this thesis is to experimentally examine the effect of important parameters on combustion phasing control, operational range extension, and pollutants. Natural gas is one of the important sources of energy in Iran and the world. Using natural gas in internal combustion engines can cause methane to slip into the atmosphere and intensify the... 

This research introduces temperature measurement by a non-intrusive pyrometric method of the ratio of two colors of soot. For pyrometry, the spectral sensitivity of the Nikon D7100 camera was obtained by developing a neural network based on the results of photographing colored papers and their spectrum, and this camera was used for temperature measurement. Based on the dependence of soot radiation on temperature and the spectral sensitivity of the camera, a calibration chart has been extracted on the ratio of the green channel to the red channel of the camera with the soot temperature, which is used to produce the temperature contour using the flame image. The temperature contour of...