scholarly journals Positronium in a Liquid Phase: Formation, Bubble State and Chemical Reactions

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Sergey V. Stepanov ◽  
Vsevolod M. Byakov ◽  
Dmitrii S. Zvezhinskiy ◽  
Gilles Duplâtre ◽  
Roman R. Nurmukhametov ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Reaction Rate ◽  
Local Heating ◽  
Bubble Radius ◽  
Annihilation Rate ◽  
Electron Pairs ◽  
Reaction Rate Constants ◽  
Slowing Down ◽  
Diffusion Controlled ◽  
Different Temperatures

The present approach describes the e+ fate since its injection into a liquid until its annihilation. Several stages of the e+ evolution are discussed: (1) energy deposition and track structure of fast positrons: ionization slowing down, number of ion-electron pairs, typical sizes, thermalization, electrostatic interaction between e+ and the constituents of its blob, and effect of local heating; (2) positronium formation in condensed media: the Ore model, quasifree Ps state, intratrack mechanism of Ps formation; (3) fast intratrack diffusion-controlled reactions: Ps oxidation and ortho-paraconversion by radiolytic products, reaction rate constants, and interpretation of the PAL spectra in water at different temperatures; (4) Ps bubble models. Inner structure of positronium (wave function, energy contributions, relationship between the pick-off annihilation rate and the bubble radius).

Development of a model for predicting reaction rate constants of organic chemicals with ozone at different temperatures

Chemosphere ◽  
2013 ◽  
Vol 92 (8) ◽  
pp. 1029-1034 ◽  
Author(s):  
Xuehua Li ◽  
Wenxing Zhao ◽  
Jing Li ◽  
Jingqiu Jiang ◽  
Jianji Chen ◽  
...  
Keyword(s):  
Rate Constants ◽  
Reaction Rate ◽  
Organic Chemicals ◽  
Reaction Rate Constants ◽  
Different Temperatures

Studies on Curing Kinetics Parameter of TDI-PPG-MOCA Polyurethane by FTIR

2011 ◽  
Vol 328-330 ◽  
pp. 966-969 ◽  
Author(s):  
Qing Zhen Wen ◽  
Chao Yu ◽  
Jin Hua Zhu ◽  
Tian Yu Liu
Keyword(s):  
Reaction Rate ◽  
Curing Kinetics ◽  
Crosslinking Reaction ◽  
Curing Process ◽  
Second Order Reaction ◽  
Reaction Rate Constants ◽  
Curing Reaction ◽  
Different Temperatures ◽  
Measured Effect ◽  
Kinetics Parameter

The curing process of polyurethanes was investigated with FTIR method. The curves of conversion (α)VS curing reaction time (t) at different temperatures were obtained .The curing reaction of the system was found to be second order reaction. The reaction rate constants and activation energy had been measured. Effect of the use lever of curing agent and temperatures on curing reaction was discussed. The results showed that when the mole ratio of NCO/OH is smaller than 1, the crosslinking reaction take place at high temperature.

scholarly journals Stability of vitamin C in broccoli at different storage conditions

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Nasser Al-Habsi ◽  
Sithara Suresh ◽  
Amani Al-Yhmedi ◽  
Marwa Al-Shoryani ◽  
Mostafa I. Waly ◽  
...  
Keyword(s):  
Activation Energy ◽  
Vitamin C ◽  
Reaction Rate ◽  
Storage Conditions ◽  
Order Reaction ◽  
Titration Method ◽  
First Order ◽  
Reaction Rate Constants ◽  
Different Temperatures ◽  
Thermal Stability Of

In this study, the retention of vitamin C in fresh broccoli stored at different temperatures (i.e. chiller, room, cooking, and roasting or baking; 5-120°C) was investigated. The thermal stability of vitamin C in broccoli was analysed at 5, 20, 45, 60, 70, 80, 110, and 120°C. The vitamin C content was measured by the indophenol titration method. Vitamin C was affected negatively at all stored temperatures. The degradation of vitamin C was modelled by first-order reaction kinetics and the reaction rate constants were observed as 9.03×10-8 and 5.65×10-3 s-1 when stored at 5°C and 120°C, respectively. The activation energy was estimated as 74.2 kJ/mol within the temperature range used in this study. The lowest decay of vitamin C was observed during the chilling condition. The data on retention of vitamin C in broccoli could be used to determine their stability, when stored as raw, and when heated at different temperatures.

scholarly journals Near diffusion-controlled reaction of a Zn(Cys)4 zinc finger with hypochlorous acid

2016 ◽  
Vol 7 (8) ◽  
pp. 5508-5516 ◽  
Author(s):  
Vincent Lebrun ◽  
Jean-Luc Ravanat ◽  
Jean-Marc Latour ◽  
Olivier Sénèque
Keyword(s):  
Zinc Finger ◽  
Rate Constants ◽  
Reaction Rate ◽  
Hypochlorous Acid ◽  
Zinc Fingers ◽  
Reaction Rate Constants ◽  
Diffusion Controlled ◽  
Diffusion Controlled Reaction

Reaction rate constants of HOCl with zinc-bound cysteines are determined, demonstrating that zinc fingers are potent targets for HOCl and may serve as HOCl sensors.

Electron behavior in mixed solvents: optical spectra and reactivities in water/alkane diols

1984 ◽  
Vol 62 (11) ◽  
pp. 2217-2222 ◽  
Author(s):  
K. M. Idriss-Ali ◽  
Gordon R. Freeman
Keyword(s):  
Optical Absorption ◽  
Reaction Rate ◽  
Composition Range ◽  
Mixed Solvents ◽  
Solvated Electrons ◽  
Reaction Rate Constants ◽  
Diffusion Controlled ◽  
Entropy Of Activation ◽  
Lower Entropy ◽  
The Difference

Investigation of the effect of solvent structure on the optical absorption spectrum and reactivity of solvated electrons has been extended to diol/water mixed solvents, using 1,2-ethanediol (12ED) and 1,4-butanediol (14BD). The large effects that had been found in mono-ol/water mixed solvents did not occur in diol/water. Although addition of 3 mol% of a diol to water increased the optical absorption energies of e−s by 0.06 eV, similar to the shift caused by addition of 3 mol% of a mono-ol, the variation of the spectrum over the rest of the composition range was nearly ideal in diol/water, in contrast to the very non-ideal variation in mono-ol/water. Reaction rate constants kS at 298 K in the diol/water mixed solvents vary approximately as the inverse viscosity,η−1.0, in the diffusion-controlled limit. However, when reactions are two or three orders of magnitude slower than diffusion controlled, kS at 298 K is independent of η. Toluene reacts with e−s at a 10−3-fold smaller rate than does nitrobenzene; the difference is nearly completely due to a ~50 J/mol K lower entropy of activation of the former reaction.

scholarly journals Aquation reaction of iminodiacetate complex of oxidovanadium(IV) with 2,2’-bipyridine induced by Fe(III) ions: Kinetic studies

2019 ◽  
Vol 44 (4) ◽  
pp. 300-306
Author(s):  
Joanna Drzeżdżon ◽  
Agnieszka Piotrowska-Kirschling ◽  
Lech Chmurzyński ◽  
Dagmara Jacewicz
Keyword(s):  
Aqueous Solutions ◽  
Computer Program ◽  
Rate Constants ◽  
Reaction Rate ◽  
Kinetic Studies ◽  
Reaction Rate Constants ◽  
Different Temperatures ◽  
Kinetics Of

The kinetics of the aquation reaction of the [VO(ida)(bipy)]·2H2O (VO(ida)(bipy)) complex (where ida = iminodiacetate anion and bipy = 2,2’-bipyridine) promoted by [Fe(H2O)6]3+ ions were investigated in aqueous solutions. Spectrophotometric studies were carried out at different temperatures in the range of 293.15–313.15 K. The concentration of the [Fe(H2O)6]3+ (Fe3+) ions was kept within the range of 2 × 10–4 to 8 × 10–4 mol L–1, and the concentration of VO(ida)(bipy) was 1 × 10–3 mol L–1. The values of the observable reaction rate constants were calculated based on the Glint computer program. Furthermore, the mechanism for the aquation of VO(ida)(bipy), induced by Fe(III) ions, has been proposed.

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