The overall goal of this experiment was to detect whether kinetic modeling can explain effects of temperature, acid concentration, time and solid contents on the production of glucose by concentrated acid hydrolysis of walnut green skin. For this purpose, sulfuric acid concentration of 20, 40 and 60% (w/w), processing temperature of 65, 80 and 90°C, reaction time of 120, 180 and 240 min and solid content of 5, 10 and 15% (w/w) were used as hydrolysis conditions. High performance liquid chromatography (HPLC) was used to analyze the products. The process was modeled by first-order irreversible reaction in series and kinetic constant, relating reaction time to glucose released. To relate temperature with kinetic constant and calculate activation energy, Arrhenius equation was employed. Optimal conditions occurred at 40% H 2 SO 4 , 90°C and 15% solid content for 285 min, which yielded a solution with 10.72 g glucose/L. In these conditions, 45% of the cellulose was hydrolyzed.
Anorthite is a rare compositional variety of plagioclase. This mineral is a type of calcium-rich plagioclase feldspar which has great properties such as low thermal expansion coefficient and high modulus of rupture. Therefore, physical properties of hard porcelain bodies will be improved by creating anorthite phase. According to limitation of anorthite natural sources, various sources were used to synthesis of anorthite. In this paper, white cement was introduced as a new calcium oxide source to reach anorthite phase. For this purpose, a standard composition for hard porcelain was prepared by addition of 50 wt% kaolin, 25 wt% potassium feldspar and 25 wt% quartz. Six additional body mixtures were formulated partially by replacing 0, 3, 4.5, 6, 7.5 and 9 wt% of potassium feldspar by white cement. The linear shrinkage, water adsorption, modulus of rapture (M.O.R), and bulk density of fired body were calculated. Phase characterization was accomplished by X-ray diffractometer (XRD) and scanning electron microscopes. By replacing potassium feldspar with white cement, anorthite was appearance in fired body at 1250 °C. This replacing decreases bulk density, linear shrinkage and modulus of rapture. Although, water adsorption and consequently firing temperature increase by replacing white cement but 1250 °C was a good temperature for firing replaced bodies.
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