Sharif Digital Repository

The purpose of this thesis is the construction of hard and tough Zirconia bodies from economical raw materials using minimum sintering time and temperature.
Stabilizers cause tetragonal particles to be remained in cubic phase. Most additives are Ca, Ce, Mg and Y ions the whole of which are rare earth elements and make solid solutions with Zirconia.
In this project different percents of CaO, MgO, CeO2, and Y2O3 were mixed with ZrO2 and they were sintered after granulation, cold pressing and Cold Isostatic Pressing. Using jar milling and fast milling, the particle size of purchased ZrO2 was reduced to 0.7 um. The whole needed additives were purchased with particle size below 300 nm.... 

Carbon dioxide emissions account for 80% of current greenhouse gas emissions that contribute to global warming; this majority stake held by carbon dioxide indicates that reduction in its release to the atmosphere and capturing emissions accomplished is imperative in conservation of human life in earth. The aim of this project is CO2 capturing from ambient air to decrease air pollution with uses building surface that is wide available surface, as basis of adsorbent. In this research, we select CaO as absorbent that it is proven good absorbent in high temperature for CO2. We studied this absorbent in low temperature and pressure. We experimented different weight amount of sorbent 2,3,4,5,6.5... 

This study aims at synthesizing and investigating of heterogeneous catalysts for biodiesel production as an alternative to fossil fuel with the transesterification of oil and methanol. Three main sections of this thesis concern the synthesis of nano-catalysts, characterization analysis, and investigation of the transesterification reaction under different condition. Two series of heterogeneous catalysts, including different molar ratios of X%Li/Ca-La (X=0-7%) and Ca/Talc (Ca, 3Ca/1Talc, 1Ca/1Talc, 1Ca/3Talc, Talc) has been synthesized as active and stable catalysts to study the transesterification reaction of canola oil and methanol for biodiesel production. Prepared catalysts have been... 

The aim of this project is to fabricate and study heterogeneous CaO-based nanocatalysts with lithium and zinc enhancers for the esterification reaction of rapeseed oil and methanol to produce biodiesel as a renewable and alternative fuel for fossil fuels. Is. First, Zn-Li / CaO catalysts with weight ratio Li: Zn: CaO, 2: 2: 7 and by combining different percentages of Li100% promoter, Li75% -Zn25%, Li50% -Zn50%, Li25% -Zn75%, 100% Zn were made on the basis of CaO by wet inoculation. Characterization tests to evaluate the structure and characterization such as X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (EDX) spectroscopy, Bruner-Emmett-Teller... 

The aim of this project is to inventigate and synthesize CaO-based nanocatalysts with metal promoters of magnesium and lithium by wet impregnation and coprecipitation methods, which are used in the transesterification reaction of canola oil and methanol. Sections of thesis include review of before researches , synthesis of nanocatalysts, catalyst characterization tests,and investigation of reaction under optimal conditions. In wet impregnation method, nanocatalysts were made with 5% by weight of lithium-magnesium on the basis of CaO and with different weight percentages of these two elements. In the co-precipitation method , catalysts with a combined base of calcium oxide/magnesium oxide ... 

Thermodynamic quantities such as proton affinity (PA) and molecular basicity (GB) for (CaO)n nanoclusters with n=2–16 have been calculated using three computational models of the DFT (B3LYP, M06, PW91, CAM–B3LYP and ωB97XD functionals), MP2, and HF with the cc-PVNZ (n = D and T) basis set in the gas phase. Absolute deviation error (AAD%) indicates that obtained PA and GB values using DFT model and the B3LYP method with mean percentage errors of 0.77 and 0.90 %, respectively, have the higher accuracy than the other methods and models. Owing to the unique physical and chemical properties of ILs, can be used as catalysts, promoters and modifiers of catalyst in many organic reactions. Therefore,...