No abstract

In present work acid resistant calcium silicate has been synthesized from silica of rice husk and calcium oxide of analytical grade. The silica from rice husk was extracted at 550^oC in amorphous form and then allowed to react with calcium oxide in the presence of excess water by Sol-Gel technique to obtain calcium silicate hydrate gels. The molar ratios of Si/Ca were adjusted each time to obtain silica rich calcium silicate hydrates. The gels were dried in oven and calcined in muffle furnace at various temperatures to obtain acid resistant calcium silicate. The products were tested by analytical technique and by FTIR and XRD machines. Studies show that at higher molar ratio of Si/Ca, the heat treatment improves the acid resistivity of calcium silicate whereas at lower molar ratios the heat treatment does not make it acid resistant

Deletion of Cu(II) from synthetic solution was investigated using ground Prunus Amygdalus shell (GPAS). FTIR revealed the probable functional groups for the binding of Cu(II). XRD revealed amorphous nature of the GPAS. SEM analysis furnished microscopic details of GPAS. GPAS size analysis was done using seven ASTM screens and three mean diameters, namely mass mean, volume mean and volume surface mean diameters. Kinetic study consisted of pseudo-first and pseudo-second order kinetics. Langmuir and Freundlich isotherms were used to elucidate the isotherm study of uptake of Cu(II) onto GPAS. Trend of Scatchard was used to verify the applicability of the Freundlich model, while D-R model helped to determine the nature of biosorption. A detailed analysis for rate controlling step was made. Various mean diameters were used to estimate the diffusion coefficient for the biosorption of Cu(II) onto GPAS.

Various siliceous agriculture waste (SAW) such as rice husk, wheat husk and bagasse have been investigated to study their thermal degradation behavior using Thermogravimetric Analyzer (TGA) technique. The focus of this research is to conduct TGA of raw and acid treated (20% HCl & 1M H2SO4) SAW at heating rate 10°C/min in the atmosphere of nitrogen. The results were analyzed on the basis of thermograms and it was inferred that 24 hours soaking with 20% HCl prior to thermal degradation enhanced the percent weight loss. The process also improved the percentage of residual weight of SAW indicating the extraction of amorphous silica with increased purity. The effect of acid treatment was verifi ed by determining chemical composition of SAW samples before and after soaking with 20% HCl. Proximate analysis, thermal degradation temperature ranges and percentage of residual weight at 800°C for each of rice husk, wheat husk and bagasse were also quantifi ed to observe the thermal degradation behavior. XRF analysis was performed to observe the effect of acid treatment for extraction of pure silica.

Detailed kinetic models are important to describe the oxidation of hydrocarbon fuels. In the present study, a detailed kinetic models has been developed to simulate the combustion of natural gas in IC engine. The proposed models consists of 208 elementary reactions and 72 species. The rate of the production and sensitivity analysis of the proposed reaction models were carried out to visualize the effect of reactions on the formation of various pollutants. In the rate of production analysis, an absolute rate of production coefficients and the normalized rate of production coefficients were calculated for the reactions involved in the formation of pollutant species (CO, NO, NO 2 , & NH 3 ). In sensitivity analysis, normalized logarithmic sensitivity coefficients were determined the reactions of rates affects the output concentrations of the pollutant species. These two analysis were carried out for two temperatures ranges i.e. 1500 °C and 4000 °C under stoichiometric conditions (when ϕ=1.0).