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Abstract  

Differential thermal analysis and thermogravimetry were used to evaluate the effect of some additives, such as CaSO4, CaCl2 and silica fume amorphous silica from ferrosilicon synthesis on the mechanism and kinetics of reactions occurring in fly ash-Ca(OH)2 system. The accelerating role of these additives was demonstrated from the data relating to Ca(OH)2 consumption in hydrated pastes, determined by TG measurements.

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Abstract  

In previous works, the effects on the devitrification mechanism of a certain composition calcium phosphate with additives of TiO2, SiO2, Al2O3, CeO2 have been studied. It was found that some metal oxide additives played a key role as the nucleation agent in calcium phosphate glass-ceramics, and the devitrification mechanism of calcium phosphate glass system was changed drastically by addition such as metal oxide. Hydroxyapatite (HAp), tricalcium phosphate (TCP) and β-calcium phosphate (β-CaP2O6) whisker are the three most biologically compatible materials to human bone in bio-ceramics field. In this work, the effect on devitrification mechanism and the physical properties of certain composition calcium phosphate glass with three above additives were investigated, and the result shown that although no fine crystalline was induced in the certain composition of calcium phosphate glass when a large amount of additive was added, but such additives play a catalyst role by lowering the activation energies of devitrification. It would supplement the mechanical properties and the biocompatibility for the calcium phosphate glasses.

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Abstract  

Properties of limestone related to SO2/SO3 reactivity were investigated. Limestone calcined under different conditions (temperature, time and with/without additives) yield calcines of distinctly different physical structures. The amount of pores and the size of the pores formed during calcination is important. The main purpose of the present work was to gain a better understanding and more reliable explanation of the temperature regime for gas desulphurization using Ca-based sorbents in atmospheric fluidized-bed combustors. Pore size, surface area and pore volume of each calcine were determined by mercury porosimetry and BET methods. At higher calcination temperature and during longer time, sintering became significant and the obtained calcine had a smaller internal surface area and thereby the average pore radius increased. The additives such as NaCl also accelerated sintering thus increasing the pore size. The measurements of porosity were supplemented by scanning electron microscopic observations employed for qualitative description of the pore structure. SEM micrographs are presented.

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Journal of Thermal Analysis and Calorimetry
Authors: I. Klimova, T. Kaljuvee, L. Türn, V. Bender, A. Trikkel, and R. Kuusik

-DTA-FTIR techniques, it was previously found that limestone and dolomite additives stabilize AN because of the interactions between AN and Ca, Mg carbonates with the formation of Ca, Mg nitrates excluding exothermic explosive decomposition of AN [ 5 , 6 ]. In order

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, potassium and sodium salts. WHO Food Additives Series No. 5. Geneva. Coverly, J., Peters, L., Whittle, E., et al.: Susceptibility to skin stinging, non-immunologic contact urticaria and acute skin

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. Freeman, San Francisco. Numerical Taxonomy. Sattath, S. and Tversky, A. 1977. Additive similarity trees. Psychometrika 42

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References [1] Gelfond , A. O. 1968 Sur les nombres, qui ont propriétés additives et multiplicatives données Acta Arithmetica

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crystallization peak ( T p2 ) for Sn additive Se–Te investigated samples. The appearance of a double glass transition temperature indicates unusual phase separation occurring during thermal treatment. The phase separation, leading to double glass transition

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mureseni legate de aditivii alimentari. (Students’ attitude, behaviour, and knowledge about food additives in Mures region) Revista de Medicina si Farmacie , 53 , 208–214. Dragoi S

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S.N. Mahindru , Food Additives: Characteristics, Detection and Estimation, McGraw-Hill, New Delhi, 2004. Mahindru S

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