Employing Magnetic Levitation To Monitor Reaction Kinetics and Measure Activation Energy

2012 ◽  
Vol 89 (6) ◽  
pp. 776-779 ◽  
Author(s):  
Lauren Benz ◽  
Karen E. Cesafsky ◽  
Tran Le ◽  
Aileen Park ◽  
David Malicky
Keyword(s):  
Activation Energy ◽  
Reaction Kinetics ◽  
Magnetic Levitation ◽  
Monitor Reaction

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.

Generation and Dissociation of Iron-Boron Pairs in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
Masashi Suezawa ◽  
Koji Sumino
Keyword(s):  
Activation Energy ◽  
Electron Paramagnetic Resonance ◽  
Reaction Kinetics ◽  
Order Reaction ◽  
Migration Energy ◽  
Paramagnetic Resonance ◽  
First Order ◽  
Pair Generation ◽  
Electron Paramagnetic ◽  
Fe Impurity

AbstractThe generation and dissociation processes of Fe-B pairs in Si crystal are investigated by means of the measurements of electron paramagnetic resonance of Si crystals of various B concentrations doped with Fe. Fe-B pairs are generated due to annealing of the crystals at temperatures around 300 K obeying to the first order reaction kinetics. The activation energy for pair generation is determined to be about 0.65 eV which is almost equal to the migration energy of Fe impurity in a Si crystal. Fe-B pairs are found to be dissociated at tempeatures higher than 150°C leading to the precipitation of Fe.

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.

scholarly journals Analysis of Iron Oxide Reduction Kinetics in the Nanometric Scale Using Hydrogen

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1276 ◽  
Author(s):  
Swathi K. Manchili ◽  
Johan Wendel ◽  
Eduard Hryha ◽  
Lars Nyborg
Keyword(s):  
Activation Energy ◽  
Iron Oxide ◽  
Reaction Kinetics ◽  
Reduction Process ◽  
Steel Powder ◽  
Surface Oxide ◽  
Oxide Reduction ◽  
Sintering Aid ◽  
Surface Iron ◽  
Reported Data

Iron nanopowder could be used as a sintering aid to water-atomised steel powder to improve the sintered density of metallurgical (PM) compacts. For the sintering process to be efficient, the inevitable surface oxide on the nanopowder must be reduced at least in part to facilitate its sintering aid effect. While appreciable research has been conducted in the domain of oxide reduction of the normal ferrous powder, the same cannot be said about the nanometric counterpart. The reaction kinetics for the reduction of surface oxide of iron nanopowder in hydrogen was therefore investigated using nonisothermal thermogravimetric (TG) measurements. The activation energy values were determined from the TG data using both isoconversional Kissinger–Akahira–Sunose (KAS) method and the Kissinger approach. The values obtained were well within the range of reported data. The reaction kinetics of Fe2O3 as a reference material was also depicted and the reduction of this oxide proceeds in two sequential stages. The first stage corresponds to the reduction of Fe2O3 to Fe3O4, while the second stage corresponds to a complete reduction of oxide to metallic Fe. The activation energy variation over the reduction process was observed and a model was proposed to understand the reduction of surface iron oxide of iron nanopowder.

Effect of Particle Size on Oxidation Reaction Kinetics Parameter of Cu2O Powders

2011 ◽  
Vol 284-286 ◽  
pp. 726-729 ◽  
Author(s):  
Zai Yuan Li ◽  
Yu Chun Zhai ◽  
Myongil Pang
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Apparent Activation Energy ◽  
Reaction Kinetics ◽  
Oxidation Reaction ◽  
Raw Materials ◽  
Particle Sizes ◽  
Oxide Powders ◽  
Effect Of Particle Size ◽  
Kinetics Parameter

The 0.4mol•L-1CuSO4liquor and 5mol•L-1NaOH liquor were prepared by CuSO4·5H2O and NaOH as raw materials. The Cu2O powders were prepared by dextrose reducer and PVP dispersant. The Cu2O oxidation reaction DTA-TG-DTG curves were obtained by SDT 2960 simultaneous DSC-TGA analysis apparatus. The mensuration condition were that rise temperature velocity 15°C·min-1and deoxidize gas air. The Cu2O oxidation reaction kinetics was calculated by DTA-TG-DTG curves data. The results indicate that the cuprous oxide powders shape were spherical, their particle’ sizes were 100,200,1000nm. Their apparent activation energy were 164.38, 175.54, 282.65 KJ·mol-1, the apparent activation energy increase with Cu2O particle’ size. Their frequency factors were 1.22×1013, 1.40×1013, 2.88×1020, the frequency factors increase with particle’ size Cu2O. Their reaction progressions were 1.02, 1.00, 0.96, the reaction progression increase with Cu2O particle’ size decreased.

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.

Oxidation of carbon monoxide by oxygen over pure and platinum-doped LaMnO3 perovskites

1990 ◽  
Vol 55 (8) ◽  
pp. 1928-1934 ◽  
Author(s):  
Jaroslav Bartoň ◽  
Vladimír Pour
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Apparent Activation Energy ◽  
Co Oxidation ◽  
Reaction Kinetics ◽  
Empirical Equation ◽  
Catalytic Activities ◽  
Surface Areas ◽  
Oxidation Of Carbon Monoxide

The properties of pure and platinum-doped LaMnO3 perovskites, including their catalytic activities for the reaction of CO with oxygen, have been determined. Perovskite samples were prepared by decomposition of lanthanum and manganese citrates. The surface areas were 12.2 m2/g for pure LaMnO3 and 9.8 m2/g for the platinum-doped sample. The doping with a small amount of platinum markedly enhances the catalytic activity of LaMnO3 perovskite. The (CO + O2) reaction starts at 200 °C over LaMnO3 and at temperatures below 100 °C over a sample doped with Pt. The reaction kinetics for both the pure and platinum-doped LaMnO3 can be described by empirical equation (4). When Pt-doped perovskite is used, an increase in the apparent activation energy occurs at about 150 °C. This fact is attributed to a change in the mechanism of CO oxidation.

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