The thermoluminescence activation energy and frequency factor of the main glow of CaSO4:Tm phosphor determined by heating rate method including very slow rates of heating

2005 ◽  
Vol 97 (12) ◽  
pp. 123523 ◽  
Author(s):  
K. Shinsho ◽  
Y. Suzuki ◽  
Y. Yamamoto ◽  
A. Urushiyama
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Frequency Factor ◽  
Rate Method

scholarly journals Investigation on the Thermoluminescence Properties of KGdF4:Sm3+ Polycrystalline

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Phan Van Do
Keyword(s):  
Activation Energy ◽  
Kinetic Parameters ◽  
Heating Rate ◽  
Impurity Concentration ◽  
Frequency Factor ◽  
Neutron Dose ◽  
Rate Variation ◽  
Hydrothermal Technique ◽  
X Ray

KGdF4 polycrystalline doped with the different concentration of Sm3+ ions were synthesized by hydrothermal technique. Thermoluminescence (TL) glow curves of samples were measured in the range from 50 oC to 400 oC after irradiating beta, neutron and X-ray radiations. The response of TL intensity to impurity concentration and neutron dose were studied in detail. The TL kinetic parameters such as activation energy (E) and frequency factor (s) were estimated by using the method of heating rate variation.

scholarly journals Using the Coats-Redfern Method during Thermogravimetric Analysis and Differential Scanning Calorimetry Analysis of the Thermal Stability of Epoxy and Epoxy/Silica Nanoparticle Nanocomposites

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Subhi A. Al-Bayaty ◽  
Raheem A.H. Al-Uqaily ◽  
Najwa J. Jubier
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Heating Rate ◽  
Silica Nanoparticle ◽  
Frequency Factor ◽  
Inert Atmosphere ◽  
Diffusion Control ◽  
Scanning Calorimetry

In this paper, we provide a study of the thermal decomposition behavior of epoxy and epoxy/silica nanoparticle nanocomposites by using thermogravimetric analysis and differential scanning calorimetry techniques at temperatures ranging from 25°C to 600°C, using a constant heating rate of 10°C per minute under inert atmosphere. With increasing silica nanoparticle percentages of 2%, 4%, 6% and 8%, the kinetic parameters of the activation energy, frequency factor, and thermodynamics property were determined at conversion ranges between 20% to 80% using the Coats-Redfern method for diffusion control reaction (Janders) model. The Arrhenius equation for epoxy decomposition at a heating rate of 10°Cper minute equaled 5.7278x e185.984/RT. Thermal decomposition occurred through two stages: (1) with volatile removal and (2) with a random chain break. The effects of variation of silica nanoparticle percentages on glass transition temperature was investigated. The activation energy, frequency factor, rate constant, and other thermodynamic properties increased with additional silica nanoparticle content due to more bonding, as it needed more heat to break.

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.

Meyer-Neldel Rule on thermal stability parameters (trap depth and frequency factor) of luminescence signals in quartz

2021 ◽  
Author(s):  
Zuzanna Kabacińska ◽  
Alida Timar-Gabor ◽  
Benny Guralnik
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Hydrogen Diffusion ◽  
Dose Range ◽  
Accurate Determination ◽  
Frequency Factor ◽  
Proton Conduction ◽  
High Dose ◽  
Compensation Law ◽  
Thermal Stability Of

<p>Thermally activated processes can be described mathematically by the Arrhenius equation. The Meyer-Neldel Rule (MNR), or compensation law, linearly relates the pre-exponent term to the logarithm of the excitation enthalpy for processes that are thermally driven in an Arrhenian manner. This empirical rule was observed in many areas of materials science, in physics, chemistry, and biology. In geosciences it was found to uphold in hydrogen diffusion (Jones 2014a) and proton conduction (Jones 2014b) in minerals.</p><p>Trapped charge dating methods that use electron spin resonance (ESR) or optically or thermally stimulated luminescence (OSL and TL) are based on the dose-dependent accumulation of defects in minerals such as quartz and feldspar. The thermal stability of these defects in the age range investigated is a major prerequisite for accurate dating, while the accurate determination of the values of the trap depths and frequency factors play a major role in thermochronometry applications. </p><p>The correlation of kinetic parameters for diffusion has been very recently established for irradiated oxides (Kotomin et al. 2018). A correlation between the activation energy and the frequency factor that satisfied the Meyer–Neldel rule was reported when the thermal stability of [AlO<sub>4</sub>/h<sup>+</sup>]<sup>0</sup> and [TiO<sub>4</sub>/M<sup>+</sup>]<sup>0</sup> ESR signals in quartz was studied as function of dose (Benzid and Timar-Gabor 2020). Here we compiled the optically stimulated luminescence (OSL) data published so far in this regard, and investigated experimentally the thermal stability of OSL signals for doses ranging from 10 to 10000 Gy in sedimentary quartz samples. We report a linear relationship between the natural logarithm of the preexponent term (the frequency factor) and the activation energy E, corresponding to a Meyer-Neldel energy of 45 meV, and a deviation from first order kinetics in the high dose range accompanied by an apparent decrease in thermal stability. The implications of these observations and the atomic and physical mechanisms are currently studied.</p><p> </p><p><strong>References</strong></p><p>Benzid, K., Timar Gabor, A. 2020. The compensation effect (Meyer–Neldel rule) on [AlO<sub>4</sub>/h<sup>+</sup>]<sup>0</sup> and [TiO<sub>4</sub>/M<sup>+</sup>]<sup>0</sup> paramagnetic centers in irradiated sedimentary quartz. <em>AIP Advance</em>s 10, 075114.</p><p>Kotomin, E., Kuzovkov, V., Popov, A. I., Maier, J., and Vila, R. 2018. Anomalous kinetics of diffusion-controlled defect annealing in irradiated ionic solids. <em>J. Phys. Chem. A</em> 122(1), 28–32</p><p>Jones, A. G. (2014a), Compensation of the Meyer-Neldel Compensation Law for H diffusion in minerals, <em>Geochem. Geophys. Geosyst.</em>, 15, 2616–2631</p><p>Jones, A. G. (2014b), Reconciling different equations for proton conduction using the Meyer-Neldel compensation rule, <em>Geochem. Geophys. Geosyst</em>., 15, 337–349</p>

scholarly journals Relation between Activation Energy and Frequency Factor

Nature ◽  
1952 ◽  
Vol 170 (4320) ◽  
pp. 290-290 ◽  
Author(s):  
M. SZWARC ◽  
D. WILLIAMS
Keyword(s):  
Activation Energy ◽  
Frequency Factor

APPLICATION OF CVD DIAMOND FILMS FOR UV THERMOLUMINESCENCE DOSIMETER

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1003-1007 ◽  
Author(s):  
J. AHN ◽  
B. GAN ◽  
Q. ZHANG ◽  
S. F. YOON ◽  
V. LIGATCHEV ◽  
...  
Keyword(s):  
Activation Energy ◽  
Glow Curve ◽  
Diamond Films ◽  
Frequency Factor ◽  
Cvd Diamond ◽  
Order Kinetic ◽  
First Order ◽  
Order Kinetic Model ◽  
Ionizing Radiations ◽  
Trap Activation

This study presents the investigation of CVD diamond for the application of an UV TL dosimeter. A 9-μm-thick film used in this study presents a TL glow curve with a well-defined first-order kinetic peak (at about 273 K), which norm ally presents in the glow curve from ionizing radiations, is not observed. By fitting the glow curve to a first-order kinetic model, the trap activation energy E t = 0.95 eV and frequency factor s = 5.6 x 106 s -1 have been resolved.

An Overview on Peak Shape Method for Thermoluminescence Glow Curve Analysis

2018 ◽  
pp. 26-52
Author(s):  
Sukhamoy Bhattacharyya ◽  
Partha Sarathi Majumdar
Keyword(s):  
Activation Energy ◽  
Glow Curve ◽  
Frequency Factor ◽  
Curve Analysis ◽  
Peak Shape ◽  
Order Of Kinetics ◽  
Symmetry Factor ◽  
Alternative Approach ◽  
General Order ◽  
Thermoluminescence Glow Curve

The shape of a thermoluminescence (TL) glow curve has fundamental importance for calculating the characteristic parameters of trap levels within the band gap. TL analysis are mostly based on the three-parameter general order kinetics model. The parameters are activation energy, order of kinetics, and frequency factor. Peak shape method is one of the most prominent methods for extracting the activation energy from a TL curve. An overview of different peak shape methods along with an alternative approach formulated directly from basic TL equations is presented in this chapter. Generally, peak shape method requires prior knowledge of order of kinetics to determine activation energy which creates a difficulty due to the non-uniqueness of symmetry factor for a particular value of order of kinetics. A modified version of peak shape method which is free from this constraint is discussed here. Activation energies from experimental curves of tremolite and actinolite are estimated using peak shape method. Limitation of peak shape method for saturated TL peaks with heavy retrapping is also discussed.

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