Sintering of a Crystallizable K2O–CaO–SrO–BaO–B2O3–SiO2 Glass with Titania Present

2002 ◽  
Vol 17 (7) ◽  
pp. 1772-1778 ◽  
Author(s):  
Jau-Ho Jean ◽  
Yu-Ching Fang ◽  
Steve X. Dai ◽  
David L. Wilcox
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Crystalline Phase ◽  
Glass Powder ◽  
Energy Analysis ◽  
Dissolution Kinetics ◽  
Critical Value ◽  
Sio2 Glass ◽  
Kinetics Of Formation ◽  
Kinetics Of

Crystallization and reaction kinetics of a crystallizable K2O–CaO–SrO–BaO–B2O3–SiO2 glass powder with 17–40 vol% titania powder were investigated. The initially amorphous K2O–CaO–SrO–BaO–B2O3–SiO2 glass powder formed cristobalite (SiO2) and pseudowollastonite [(Ca, Ba, Sr)SiO3] during firing. The above crystalline phases were completely replaced by a crystalline phase of titanite [(Ca, Sr, Ba)TiSiO5] when the amount of added titania was greater than a critical value, e.g., 10 vol%, at 99–1100 °C. A chemical reaction taking place at the interface between titania and the glass was attributed to the above observation. The dissolved titania changed the composition of the glass, and the dissolution kinetics was much faster than the formation of cristobalite and pseudowollastonite. Activation energy analysis showed that the crystallization of titanite [(Ca,Sr,Ba)TiSiO5] was controlled by a reaction-limiting kinetics of formation for the Ti–O bond.

scholarly journals Degradation Kinetics of Anthocyanins in Shalgam Beverage

2019 ◽  
Vol 7 (2) ◽  
pp. 282
Author(s):  
Adnan Bozdoğan ◽  
Kurban Yaşar
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Half Life ◽  
Degradation Kinetics ◽  
Production Method ◽  
Order Reaction ◽  
Different Temperatures ◽  
Traditional Production ◽  
Effects Of Temperature ◽  
Kinetics Of

This research was performed to elucidate the effects of temperature on the degradation kinetics of anthocyanins in shalgam beverage. Shalgam beverage was produced according to traditional production method. Then, it was kept at three different temperatures (65°C, 75°C, and 85°C) for 12 hours, and the relevant quantities of anthocyanins were determined thereafter. The research revealed that degradation of the anthocyanins was well described with a 1st-order reaction kinetics model and the R2 values varied in the range of 0.9059-0.9715. Activation energy of the reaction was determined to be 48537 Joule/mole. The half-lives of anthocyanins at 65°C and 75° C, and 85°C were found to be 138.63, 136.72, and 51.57, respectively. Compared the half-life periods at different temperatures, anthocyanins were found to be more resistant at 65°C and 75°C than at 85°C.

Chromatographic study of reaction kinetics of formation and degradation of polyamido acid

1985 ◽  
Vol 34 (9) ◽  
pp. 1842-1847 ◽  
Author(s):  
V. P. Sklizkova ◽  
L. Z. Vilenchik ◽  
V. V. Kudryavtsev ◽  
T. B. Tennikova ◽  
N. G. Bel'nikevich ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Chromatographic Study ◽  
Polyamido Acid ◽  
Kinetics Of Formation ◽  
Kinetics Of

Cinétique de la formation de la métalloporphyrine Cu(II)—dérivé tétra éthylènediamino de la protoporphyrine IX (ENP) en milieu aqueux

1979 ◽  
Vol 57 (22) ◽  
pp. 2916-2922 ◽  
Author(s):  
Guy Paquette ◽  
Miklos Zador
Keyword(s):  
New Species ◽  
Reaction Kinetics ◽  
Side Chains ◽  
Mixed Complex ◽  
Final Reaction Product ◽  
Final Reaction ◽  
Kinetics Of Formation ◽  
Degree Of Association ◽  
Kinetics Of ◽  
A New Species

The kinetics of formation of the metalloporphyrin Cu(II)–ENP is dependent on the pH due to the protonation of the pyrrol nitrogen atoms and the protonation of the diamino groups of the side chains. The degree of protonation of these side chains also influences the degree of association of the prophyrin and the metalloporphyrin in solution. The order of reaction with respect to the porphyrin is not unity, a consequence of an inhibition by the reaction product; this inhibition operates via the formation of a new species, a mixed complex of porphyrin–metalloporphyrin of low reactivity.The order of reaction with respect to Cu(II) is also not unity, a consequence of the chelation of Cu(II) by the diamino groups of the side chains. The presence of Cu(II) ligands influence both the reaction kinetics and the nature of the final reaction product. [Journal translation]

Thermal Reaction Kinetics of Fly Ash Cement Paste at the Age of 28 Days

2014 ◽  
Vol 668-669 ◽  
pp. 91-94 ◽  
Author(s):  
Xiao Fang He ◽  
Chang Wen Miao ◽  
Yong Hao Wu ◽  
Xin Xin Cao ◽  
Dan Liu
Keyword(s):  
Activation Energy ◽  
Fly Ash ◽  
Apparent Activation Energy ◽  
Reaction Kinetics ◽  
Thermal Reaction ◽  
Physical Parameters ◽  
Scanning Calorimetry ◽  
Kinetics Parameters ◽  
Cement Pastes ◽  
Kinetics Of

The thermal reaction kinetics of fly ash cement pastes were studied by Differential Scanning Calorimetry (DSC) and Thermal Gravity Analysis-Differential Thermal Gravity (TG-DTG) method, the kinetics parameters such as apparent activation energy was calculated by the Kissinger method, and the physical parameters were obtained. The result show that the fly ash cement pastes performance three endothermic reaction stages at different heating rates, peak temperatures of each stage at the range of 91.85~121.08°C, 453.93~496.48°C, and 680.21~751.62°C. TG-DTG show there were three thermal decomposition stages, thermal dehydration reaction apparent activation energy of fly ash cement pastes in each stage were 47.23kJ/mol, 128.84kJ/mol, and 134.07kJ/mol.

Reaction Kinetics of Fe2O3 and BaCO3 to Prepare Ba2Fe2O5

2014 ◽  
Vol 33 (4) ◽  
pp. 319-323 ◽  
Author(s):  
Jun-Hao Liu ◽  
Guo-Hua Zhang ◽  
Kuo-Chih Chou
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Activation Energy ◽  
Global Warming ◽  
Reaction Kinetics ◽  
Isothermal Condition ◽  
Product Layer ◽  
Thermo Gravimetric ◽  
Thermo Gravimetric Analyzer ◽  
Kinetics Of

AbstractCarbon dioxide is a greenhouse gas and substantially affects the global warming and climate change, so study on the adsorption of carbon dioxide is very urgent. As a new CO2 captor, Ba2Fe2O5 was prepared by the solid state reaction of Fe2O3 with BaCO3, following formula Fe2O3 + 2BaCO3 = Ba2Fe2O5 + 2CO2. The reaction kinetics in isothermal condition was investigated by using the method of thermo-gravimetric analyzer (TGA). It was found that the reaction of Fe2O3 with BaCO3 was controlled by the diffusion step in the product layer, and the kinetics process could be described by the RPP model (Real Physical Picture) with the apparent activation energy extracted to be 161.122 kJ/mol.

Reaction kinetics of formation of hydrochloric acid in municipal refuse incinerators

1983 ◽  
Vol 22 (1) ◽  
pp. 144-149 ◽  
Author(s):  
Shigeo Uchida ◽  
Hiroshi Kamo ◽  
Hiroshi Kubota ◽  
Ken Kanaya
Keyword(s):  
Hydrochloric Acid ◽  
Reaction Kinetics ◽  
Kinetics Of Formation ◽  
Municipal Refuse ◽  
Kinetics Of

Kinetic mechanisms for mullite formation from sol-gel precursors

1990 ◽  
Vol 5 (9) ◽  
pp. 1963-1969 ◽  
Author(s):  
Dong X. Li ◽  
William J. Thomson
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Single Phase ◽  
Sol Gel ◽  
Mullite Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Controlled ◽  
Kinetic Mechanisms ◽  
Kinetics Of

The reaction kinetics for the formation of mullite (3Al2O3 · 2SiO2) from sol-gel derived precursors were studied using dynamic x-ray diffraction (DXRD) and differential thermal analysis (DTA). The reaction kinetics of diphasic and single phase gels are compared and different reaction mechanisms are found for each gel. Mullite formation in the diphasic gel exhibits an Avrami type, diffusion-controlled growth mechanism with initial mullite formation temperatures of about 1250 °C and an activation energy on the order 103 kJ/mole. On the other hand, mullite formation from the single phase gel is a nucleation-controlled process with an initial formation temperature of 940 °C and a much lower activation energy of about 300 kJ/mole.

Calorimetric Studies of Dissolution Kinetics of Ni2(Cr,Mo) Phase in Ni-Cr-Mo Alloys Using Non-Isothermal Approach

2008 ◽  
Vol 279 ◽  
pp. 111-116 ◽  
Author(s):  
H.C. Pai ◽  
Bikas C. Maji ◽  
A. Biswas ◽  
Madangopal Krishnan ◽  
M. Sundararaman
Keyword(s):  
Activation Energy ◽  
Dissolution Kinetics ◽  
Scanning Calorimetry ◽  
Alloy Matrix ◽  
Nickel Chromium ◽  
Chromium Alloys ◽  
Kinetics Of Dissolution ◽  
Calorimetric Studies ◽  
Kinetics Of ◽  
Complex Nickel

The kinetics of dissolution of ordered phase with Pt2Mo structure has been studied in two nickel chromium alloys – one without molybdenum and another with molybdenum - using differential scanning calorimetry. The activation energy for dissolution, determined using three nonisothermal approaches was found to be ~ 418 kJ /mole for both the alloys. This value agreed very well with the activation energy for coarsening of g″ precipitates in Ni-Cr-Mo matrix and is close to activation energy for mobility of chromium and molybdenum in complex nickel alloy matrix.

Study on Oxidation Kinetics of Catalytic Oxidation of Magnesium Sulfite

2011 ◽  
Vol 391-392 ◽  
pp. 1350-1353
Author(s):  
Tong Zhu ◽  
Xiao Yan Qi ◽  
Zhong Yuan Wang ◽  
Fang Yu ◽  
An An Liu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Oxidation Kinetics ◽  
Reaction Rate ◽  
Catalyst Concentration ◽  
Oxidation Process ◽  
Sulfate Concentration ◽  
Air Compressors ◽  
Kinetics Of ◽  
Temperature Time

This paper presented a study on the reaction kinetics of magnesium sulfite catalyzed by Catalyst TR. Used a Lib-scale Plexiglas reactor aerated by air compressors to research the oxidation process Influence by pH, catalyst concentration, aeration quantity, temperature, time, sulfate concentration. Through experiment concluded the activation energy, got the formula between reaction rate and sulfate concentration.

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