scholarly journals Kinetic Models of Integrated Solidification and Cementation of Cementformation Interface with New Method

2013 ◽  
Vol 7 (1) ◽  
pp. 9-17
Author(s):  
Jun Gu ◽  
Pei Zhong ◽  
Wenzheng Qin ◽  
Haoya Liu ◽  
Lifei Dong ◽  
...  
Keyword(s):  
Activation Energy ◽  
Kinetic Models ◽  
Initial Temperature ◽  
Reaction Order ◽  
Preexponential Factor ◽  
Exothermic Peak ◽  
Temperature Peak ◽  
Final Temperature ◽  
Natural Logarithm ◽  
Solidification Reaction

The isolation failure of cement-formation interface is an important and urgent problem in oil production, while an effective way to solve it is to realize the integrated solidification and cementation of cement-formation interface (ISCCFI). In order to study the kinetics of ISCCFI with MTA (Mud Cake to Agglomerated Cake) method, the Diamond Differential Scanning Calorimetry Analyzer is adopted for experiments with dynamic method and isothermal method. The results show that there is a linear relationship between the solidification reaction temperature and the heating rate of ISCCFI with MTA method. For the first exothermic peak, the initial temperature, peak tip temperature and final temperature are 53 °C, 69 °C and 83 °C respectively, and the apparent activation energy of solidification reaction is 44.39×10-3 kJ.;mol-1, the natural logarithm of preexponential factor is 7.26, the solidification reaction order is 0.88. For the second exothermic peak, the initial temperature, peak tip temperature and final temperature are 83 °C, 92 °C and 114 °C respectively, and the apparent activation energy of solidification reaction is 99.14×10-3 kJ.;mol-1, the natural logarithm of preexponential factor is 24.77, the solidification reaction order is 0.94. The maximum solidification reaction rates at 50 °C, 75 °C and 90 °C are 0.09×10-3 s-1, 0.27×10-3 s-1 and 0.51×10-3 s-1 respectively. The kinetic models of ISCCFI with MTA method under different temperatures are established. It provides a theoretical and technical support for the isolation improvement of cement-formation interface.

scholarly journals Study of Dielectric Relaxation Behavior of Liquid Crystal Copolyester Vectra-A by Thermally Stimulated Discharge Current Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sapna Kalia ◽  
J. K. Sharma ◽  
Vandana Sharma
Keyword(s):  
Activation Energy ◽  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Preexponential Factor ◽  
Relaxation Behavior ◽  
Depolarization Current ◽  
Temperature Range ◽  
Natural Logarithm ◽  
Relaxation Parameters ◽  
Dielectric Relaxation Behavior

The dielectric relaxation behavior of thermotropic liquid crystal copolyester of 73% of p-hydroxy-benzoic acid (HBA) and 27% of 2-hydroxy-6-naphthoic acid (HNA) (Vectra-A) at poling temperature 80°C has been studied using thermally stimulated depolarization current (TSDC) technique in the temperature range from 15°C to 250°C. The TSD currents were obtained for different polarizing fields ranging from 3.8 kV/cm to 19.2 kV/cm. TSD current spectra in the temperature range from 15°C to 250°C show three current maxima around 25°C, 110°C, and 220°C. The maxima around 25°C and 110°C correspond to characteristic dipolar relaxations β and α, respectively. The peak around 220°C is due to space charge effects named as δ-relaxation. The various relaxation parameters like activation energy (U), relaxation strength , preexponential factor , the quantity of charge released (Q) and concentration of trap for β- and α-relaxations at polarizing temperature 80°C for different polarizing fields were evaluated using Bucci-Fieschi fit. The linear variation between activation energy and natural logarithm of preexponential factor indicates the presence of compensation effect for dipolar relaxations of Vectra-A under present poling conditions.

scholarly journals Study on the Size-Dependent Oxidation Reaction Kinetics of Nanosized Zinc Sulfide

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qing-Shan Fu ◽  
Yong-Qiang Xue ◽  
Zi-Xiang Cui ◽  
Ming-Fang Wang
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Surface Energy ◽  
Apparent Activation Energy ◽  
Zinc Sulfide ◽  
Rate Constant ◽  
Oxidation Reaction ◽  
Reaction Order ◽  
Preexponential Factor ◽  
Surface Entropy

Numerous oxidation problems of nanoparticles are often involved during the preparation and application of nanomaterials. The oxidation rate of nanomaterials is much faster than bulk materials due to nanoeffect. Nanosized zinc sulfide (nano-ZnS) and oxygen were chosen as a reaction system. The influence regularities were discussed and the influence essence was elucidated theoretically. The results indicate that the particle size can remarkably influence the oxidation reaction kinetics. The rate constant and the reaction order increase, while the apparent activation energy and the preexponential factor decrease with the decreasing particle size. Furthermore, the logarithm of rate constant, the apparent activation energy and the logarithm of preexponential factor are linearly related to the reciprocal of particle diameter, respectively. The essence is that the rate constant is influenced by the combined effect of molar surface energy and molar surface entropy, the reaction order by the molar surface area, the apparent activation energy, by the molar surface energy, and the preexponential factor by the molar surface entropy. The influence regularities and essence can provide theoretical guidance to solve the oxidation problems involved in the process of preparation and application of nanomaterials.

The Effects of Particle Size on the Kinetic Parameters in the Reaction of Nano-Nio with Sodium Bisulfate Solution

2011 ◽  
Vol 36 (4) ◽  
pp. 329-341 ◽  
Author(s):  
Yongqiang Xue ◽  
Xiaopeng Wang ◽  
Zixiang Cui
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Apparent Activation Energy ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Reaction Order ◽  
Particle Diameter ◽  
Preexponential Factor ◽  
Exponential Factor ◽  
Sodium Bisulfate

The kinetic parameters for the chemical reaction of nano-NiO of different particle sizes with aqueous sodium bisulfate solution were determined; additionally, the influence of particle size on the kinetic parameters were studied and were discussed. The results show that: there are clear effects of the particle size of nano-NiO on the rate constant, the reaction order, the apparent activation energy and the pre-exponential factor; thus the rate constant and the reaction order increase, and the apparent activation energy and the pre-exponential factor decrease, with decrease of the particle diameter; the logarithm of the preexponential factor, and the apparent activation energy, exhibit a linear relationship with the reciprocal of the particle diameter respectively. The bases of the role of the particle size are that the reaction order is influenced by the molar surface area of nano-NiO, the apparent activation energy by the molar surface energy, the preexponential factor by the molar surface entropy, and the rate constant by both the molar surface energy and the molar surface entropy.

Catalyst Selection for Hydrogenation of 1,2-Dihydroacenaphthylene

1998 ◽  
Vol 63 (11) ◽  
pp. 1945-1953 ◽  
Author(s):  
Jiří Hanika ◽  
Karel Sporka ◽  
Petr Macoun ◽  
Vladimír Kysilka
Keyword(s):  
Activation Energy ◽  
Nickel Catalyst ◽  
Palladium Catalyst ◽  
Active Component ◽  
Reaction Order ◽  
Nickel Catalysts ◽  
Practical Application ◽  
Repeated Use ◽  
Selection For ◽  
Catalyst Selection

The activity of ruthenium, palladium, and nickel catalysts for the hydrogenation of 1,2-dihydroacenaphthylene in cyclohexane solution was studied at temperatures up to 180 °C and pressures up to 8 MPa. The GC-MS technique was used to identify most of the perhydroacenaphthylene stereoisomers, whose fractions in the product were found dependent on the nature of the active component of the catalyst. The hydrogenation was fastest on the palladium catalyst (3% Pd/C). The nickel catalyst Ni-NiO/Al2O3, which is sufficiently active also after repeated use, can be recommended for practical application. The activation energy of 1,2-dihydroacenaphthylene hydrogenation using this catalyst is 17 kJ/mol, the reaction order with respect to hydrogen is unity.

scholarly journals Thermal Degradation Behaviour of Ni(II) Complex of 3,4-Methylenedioxaphenylaminoglyoxime

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Emin Karapınar ◽  
Ilkay Hilal Gubbuk ◽  
Bilge Taner ◽  
Pervin Deveci ◽  
Emine Ozcan
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermal Degradation ◽  
Metal Complex ◽  
Kinetic Parameters ◽  
Preexponential Factor ◽  
Degradation Behaviour ◽  
Mechanism Of Decomposition ◽  
Pyrolytic Decomposition

Thermal degradation behaviour of the Ni(II) complex of 3,4-methylenedioxaphenylaminoglyoxime was investigated by TG, DTA, and DTG at a heating rate of 10°C min−1under dinitrogen. The acquired experimental data shows that the complex is thermally stable up to 541 K. The pyrolytic decomposition process occurs by melting metal complex and metal oxide remains as final product. The energies of the reactions involved and the mechanism of decomposition at each stage have been examined. The values of kinetic parameters such as activation energy (E), preexponential factor (A) and thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) are also evaluated.

Dynamic Model of Rapeseed Oil Hydrolysis Reaction in Sub-Critical Water

2013 ◽  
Vol 860-863 ◽  
pp. 510-513 ◽  
Author(s):  
Yi Zhe Li ◽  
Hua Wang ◽  
Gui Rong Bao
Keyword(s):  
Activation Energy ◽  
Reaction Time ◽  
Dynamic Model ◽  
Rapeseed Oil ◽  
Reaction Order ◽  
Volume Ratio ◽  
Hydrolysis Reaction ◽  
Water Volume ◽  
Oil Water ◽  
Oil Hydrolysis

Experiments of Rapeseed Oil Hydrolysis Reaction in Sub-Critical Water (250-300°C, 5-60min) are Conducted in this Paper. Results Show that the Best Conditions for Rapeseed Oil Hydrolysis are Reaction Temperature 290°C, Oil-Water Volume Ratio 1:3, Reaction Time 40min, and Conversion Rate 98.9%. Meanwhile, Kinetic Analysis of this Hydrolysis Reaction is Presented. we Learn that Hydrolysis Reaction Order is 0.7778, Activation Energy is 55.34kJ/mol and the Dynamic Model is .

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.

scholarly journals YIELD OF A PORTABLE SAWMILL AND WOOD DRYING OF Hovenia dulcis IN CONVENTIONAL KILN

FLORESTA ◽  
2018 ◽  
Vol 49 (1) ◽  
pp. 079
Author(s):  
Raquel Marchesan ◽  
Pedro Lício Loiola ◽  
Morgana Cristina França ◽  
Claudio Gumane Francisco Juízo ◽  
Márcio Pereira da Rocha ◽  
...  
Keyword(s):  
Initial Temperature ◽  
Operational Efficiency ◽  
Moisture Loss ◽  
Low Permeability ◽  
Drying Method ◽  
Drying Process ◽  
Diameter Class ◽  
Final Temperature ◽  
Conventional Kiln Drying ◽  
Hovenia Dulcis

The objective of this work was to evaluate the yield of sawn wood and the operational efficiency in the sawing of Hovenia dulcis logs in a portable sawmill, as well as to evaluate the behavior of the wood in conventional kiln drying. For this purpose, five trees were selected, from which 14 logs of 1.8  meters in length were obtained to determine the volume, the yield of two diametric classes (20 to 24 and 24.1 to 28 cm) and the operational efficiency during the sawing of the logs. For the drying process, the parameters of initial temperature, final temperature and drying potential were obtained from the drastic drying method at 100ºC. The yield results showed that there were no statistical differences between the two diametric grades. For operational efficiency, the highest diameter class (1.00m³/worker/day) was higher than the lower diameter class (0.70m²/worker/day). For the drying of Hovenia dulcis wood, it is possible to consider this species as a difficult drying type according to the parameters found for the elaboration of the drying programs. In addition, the moisture loss of the wood occurred slowly due to its low permeability.

scholarly journals Neutrino Cooling of Primordial Hot Regions

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1442
Author(s):  
Konstantin Belotsky ◽  
Mohamed El Kasmi ◽  
Sergey Rubin
Keyword(s):  
Symmetry Breaking ◽  
Lower Limit ◽  
Particle Concentration ◽  
Initial Temperature ◽  
Nuclear Reactions ◽  
Threshold Effect ◽  
Final Temperature ◽  
Hot Matter ◽  
Density Inhomogeneities

The effect of neutrino cooling of possible primary regions filled by hot matter is discussed. Such regions could be obtained from the primordial density inhomogeneities and survive up to the modern epoch. The inhomogeneities could be caused by a symmetry breaking during the inflationary stage. We show that the final temperature of such region should be ∼10 keV provided that the initial temperature is within the interval 10 keV ÷ 100 MeV. The cooling is realized due to the weak nuclear reactions containing n−p transition. The lower limit 10keV is accounted for by suppression of the reactions rates because of the threshold effect and particle concentration decrease.

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