A new method of evaluation of melt/crystal interfacial energy and activation energy of diffusion

2008 ◽  
Vol 310 (6) ◽  
pp. 1281-1286 ◽  
Author(s):  
K.K. Tanaka ◽  
T. Yamamoto ◽  
K. Nagashima ◽  
K. Tsukamoto
Keyword(s):  
Activation Energy ◽  
Interfacial Energy ◽  
New Method ◽  
Method Of Evaluation ◽  
Activation Energy Of Diffusion

Electroreduction of Cr(VI) from solutions of bifunctional alcohols

1989 ◽  
Vol 54 (10) ◽  
pp. 2638-2643
Author(s):  
David I. Balanchivadze ◽  
Tamara R. Chelidze ◽  
Jondo J. Japaridze
Keyword(s):  
Activation Energy ◽  
Ethylene Glycol ◽  
Electrode Surface ◽  
Frequency Factor ◽  
Limiting Current ◽  
Factor Log ◽  
Standard Rate ◽  
Standard Rate Constant ◽  
Chromate Ion ◽  
Activation Energy Of Diffusion

The effect of bifunctional alcohols ethylene glycol (EG) and 1,2-propylene glycol (1,2 PG) on the kinetic parameters for the irreversible chromate ion reduction were investigated by polarographic and coulometric methods of analysis. The electroreduction of chromate ion in neutral bifunctional alcohol solutions proceeds according to the scheme: Cr(VI)–Cr(III)–Cr(II) and the values of the standard rate constant k*0 decrease in the order H2O > EG > 1,2 PG. The values of real activation energy, Q, activation energy of diffusion, QD, and frequency factor log A° have been calculated. The obtained values of QD as well as Q proved the diffusion nature of limiting current. The values of the frequency factor log A° decrease in the order H2O > EG > 1,2 PG, which points to a less favourable orientation of the electroactive ions at the electrode surface in glycols.

New method of evaluation of the kinetic parameters of bi-exponential enzyme-catalyzed reactions

1998 ◽  
Vol 30 (6) ◽  
pp. 735-743 ◽  
Author(s):  
Carmelo Garrido-del Solo ◽  
Francisco Garcı́a-Cánovas ◽  
José Tudela ◽  
Bent H. Havsteen ◽  
Ramón Varón-Castellanos
Keyword(s):  
Kinetic Parameters ◽  
New Method ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions ◽  
Method Of Evaluation

THE RATE OF ADSORPTION OF SOME LOW BOILING GASES ON A MODIFIED SARAN CHARCOAL

1955 ◽  
Vol 33 (2) ◽  
pp. 344-351 ◽  
Author(s):  
J. R. Dacey ◽  
D. G. Thomas
Keyword(s):  
Activation Energy ◽  
Pore Structure ◽  
Temperature Variation ◽  
New Method ◽  
Adsorption Experiment ◽  
Vinylidene Chloride ◽  
Adsorption Of Nitrogen

The pyrolysis at 300 °C. of vinylidene chloride monomer adsorbed on Saran charcoal alters the pore structure of the charcoal so that low boiling gases such as nitrogen are adsorbed slowly. The rates of adsorption of nitrogen, argon, and methane have been measured. They were found to vary with pressure and temperature, and from the temperature variation an activation energy may be calculated. A new method of determining this energy is described which involves changing the temperature during only one adsorption experiment.

scholarly journals Diffusion Coefficients of n-Alkanes and 1-Alcohols in Polyethylene Naphthalate (PEN)

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Johann Ewender ◽  
Frank Welle
Keyword(s):  
Activation Energy ◽  
Data Storage ◽  
Diffusion Coefficients ◽  
Food Packaging ◽  
Light Emitting Diode ◽  
Preexponential Factor ◽  
Barrier Properties ◽  
Molecular Volume ◽  
Polyethylene Naphthalate ◽  
Activation Energy Of Diffusion

Polyethylene naphthalate (PEN) is a polyester polymer with well-known good barrier properties. PEN had been used in the food packaging area till 2012 especially as refillable bottles for soft drinks, juices, and beer. Now, PEN is mainly used in technical applications, e.g., for data storage tapes and organic light-emitting diode (OLED) applications. The aim of the study was the determination of the diffusion coefficients of organic molecules (n-alkanes, 1-alcohols) in PEN. Diffusion and partition coefficients were determined from the lag times of the permeation process of the permeants through a commercial 12 μm biaxial-oriented PEN film. In addition, activation energies of diffusion EA were calculated according to the Arrhenius approach. The activation energy of diffusion EA follows a correlation with the molecular volume V of the investigated permeants. In addition, the preexponential factor D0 follows a correlation with the activation energy of diffusion EA. The results of this study for PEN (e.g., EA, DP) were compared to literature data on PET.

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