scholarly journals Effect of Substituting CaO with BaO and CaO/Al2O3 Ratio on the Viscosity of CaO–BaO–Al2O3–CaF2–Li2O Mold Flux System

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 142 ◽  
Author(s):  
Zhirong Li ◽  
Xinchen You ◽  
Min Li ◽  
Qian Wang ◽  
Shengping He ◽  
...  
Keyword(s):  
Activation Energy ◽  
Prediction Model ◽  
Mold Flux ◽  
Optical Basicity ◽  
Viscosity Method ◽  
Flux System ◽  
Rotational Viscosity ◽  
Viscosity Prediction ◽  
Measured Viscosity ◽  
Good Agreement

The effect of substituting CaO with BaO and CaO/Al2O3 ratio on the viscosity of CaO–BaO–Al2O3–CaF2–Li2O mold flux system was studied by rotational viscosity method. The results showed that the viscosity increased with increasing BaO as a substitute for CaO, while the viscosity decreased with the increase in CaO/Al2O3 ratio. The viscous activation energy of the slags is from 92.1 kJ·mol−1 to 133.4 kJ·mol−1. Either the Arhenius or the Weymann–Frenkel equation can be applied to establish the viscosity prediction model. In this paper, the Weymann–Frenkel equation and a new optical basicity with regard to Al2O3 as an acidic oxide were applied to the modified NPL model for predicting the viscosity of CaO–BaO–Al2O3–CaF2–Li2O mold flux system. The estimated viscosity is in good agreement with the measured viscosity.

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

scholarly journals Drying characteristics and kinetics of fluidized bed dried potato

2008 ◽  
Vol 19 (2) ◽  
pp. 127 ◽  
Author(s):  
S.B. BAKAL ◽  
K.H. GEDAM ◽  
G.P. SHARMA
Keyword(s):  
Activation Energy ◽  
Developed Countries ◽  
Moisture Diffusivity ◽  
Drying Characteristics ◽  
Effective Moisture ◽  
Air Temperatures ◽  
Processed Products ◽  
Drying Conditions ◽  
Kinetics Of ◽  
Good Agreement

In developed countries, more than 50% potatoes are consumed as processed products. As drying is the vital phenomenon in processing, it is necessary to investigate the drying characteristics and its kinetics. In this experimental study, drying kinetics of Potato in two different shape of cuboidal & cylindrical with three aspect ratio was investigated as a function of drying conditions. Experiments were conducted using air temperatures of 50, 60 and 70 ºC, at velocity of 7 ms-1. The experimental moisture data were fitted to Page and simple models available in the literature, and a good agreement was observed. The Page model gave better fit than simple model. In the ranges covered, the values of the effective moisture diffusivity, Deff were obtained between 2.278 × 10-9 to 3.314 × 10-8 m2s-1 from the Fick's diffusion model. Using Deff, the value of activation energy (Ea) was determined assuming the Arrhenius-type temperature relationship.

Insect blood-brain barrier: a radioisotope study of the kinetics of exchange of a liposoluble molecule (n-butanol)

1976 ◽  
Vol 64 (1) ◽  
pp. 119-130
Author(s):  
M. V. Thomas
Keyword(s):  
Activation Energy ◽  
Temperature Sensitivity ◽  
Nerve Cord ◽  
Previous Investigation ◽  
Time Course ◽  
Kcal Mole ◽  
Similar Time ◽  
Kinetics Of ◽  
Butanol Concentration ◽  
Good Agreement

About 90% of the butanol uptake by the cockroach abdominal nerve cord washed out with half-times of a few seconds, in good agreement with an electrophysiological estimate, and the temperature sensitivity suggested an activation energy of 3 Kcal mole-1. The remaining activity washed out far more slowly, with a similar time course to that observed in a previous investigation which had not detected the fast fraction. Its size was similar to the non-volatile uptake, and was considerably affected by the butanol concentration and incubation period. It apparently consisted of butanol metabolites, which could be detected by chromatography.

Improvement of the Blast Furnace Viscosity Prediction Model Based on Discrete Points Data

2014 ◽  
Vol 46 (1) ◽  
pp. 378-387 ◽  
Author(s):  
Hongwei Guo ◽  
Mengyi Zhu ◽  
Xinyu Li ◽  
Jian Guo ◽  
Shen Du ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Prediction Model ◽  
Model Based ◽  
Viscosity Prediction

Prediction of Field Aging Gradient in Asphalt Pavements

2015 ◽  
Vol 2507 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Xue Luo ◽  
Fan Gu ◽  
Robert L. Lytton
Keyword(s):  
Activation Energy ◽  
Prediction Model ◽  
Prediction Models ◽  
Fast Rate ◽  
Chemical Properties ◽  
Asphalt Pavements ◽  
Model Parameters ◽  
Void Content ◽  
Constant Rate ◽  
Rate Period

The aging of asphalt pavements is a key factor that influences pavement performance. Aging can be characterized by laboratory tests and prediction models. Common aging prediction models use the change of physical or chemical properties of asphalt binders based on regression techniques or aging reaction kinetics. The objective of this study was to develop a kinetics-based aging prediction model for the mixture modulus gradient in asphalt pavements to study long-term in-service aging. The proposed model was composed of three submodels for baseline modulus, surface modulus, and aging exponent to define the change of the mixture modulus with pavement depth. The model used kinetic parameters (aging activation energy and preexponential factor) of asphalt mixtures and combined the two reaction rate periods (fast-rate and constant-rate). Laboratory-measured modulus gradients of 29 field cores at different ages were used to determine the model parameters. The laboratory testing condition was converted to the field condition at a given age and corresponding temperature by introducing the rheological activation energy to quantify the temperature dependence of field cores at each age. The end of the fast-rate period or the beginning of the constant-rate period was accurately identified to model these two periods and to determine the associated parameters separately. The results showed that the predictions matched well with the measurements and the calculated model parameters were verified. The proposed aging prediction model took into account the major factors that affect field aging speed of an asphalt pavement, such as the binder type, aggregate type, air void content, pavement depth, aging temperature, and aging time.

Modeling of Non-Isothermal Austenite Formation in Cr5 Roller Steel

2013 ◽  
Vol 712-715 ◽  
pp. 34-37
Author(s):  
Fang Zhang
Keyword(s):  
Activation Energy ◽  
Heating Rate ◽  
Continuous Heating ◽  
Austenite Formation ◽  
Transformation Kinetics ◽  
Isothermal Heating ◽  
Critical Temperatures ◽  
Modified Model ◽  
Logarithmic Relationship ◽  
Good Agreement

A modified model describing the austenite reaction was developed that took into account the effect of heating rate. The model considered the variation of activation energy during non-isothermal heating and one set of model parameter was adequate to predict the formation of austenite. To verify the theoretical model, the process of austenite formation during continuous heating in Cr5 roller steel with pearlite and ferrite mixed initial microstructure was analyzed by dilatation experiment. The results show that a strong logarithmic relationship between apparent activation energy and heating rate. Experimental kinetic transformations as well as critical temperatures of austenite reaction are in good agreement with the calculations. The model can be used to describe the transformation kinetics at an intermediate heating rate.

THE PREPARATION, PURIFICATION, PHYSICAL PROPERTIES AND HYDROLYSIS OF CYANOGEN CHLORIDE

1947 ◽  
Vol 25b (4) ◽  
pp. 381-386 ◽  
Author(s):  
D. E. Douglas ◽  
C. A. Winkler
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Vapour Pressure ◽  
Freezing Point ◽  
Cyanogen Chloride ◽  
Hydrolysis Of ◽  
Good Agreement

Cyanogen chloride, prepared by the method of Jennings and Scott, has been fractionally recrystallized to a constant freezing point of −6.90 °C. Vapour pressure values for material purified in this way are in good agreement with the data of Klemenc and Wagner. The activation energy for the hydrolysis of cyanogen chloride at pH 4 to 6 between 0° and 50 °C. is approximately 21 kcal. per mole.

Failure Prediction Criteria for Fretting Wear

1982 ◽  
Vol 104 (3) ◽  
pp. 619-625 ◽  
Author(s):  
H. Lyons ◽  
J. A. Collins
Keyword(s):  
Prediction Model ◽  
Linear Prediction ◽  
Failure Prediction ◽  
Experimental Results ◽  
Fretting Wear ◽  
Structural Failure ◽  
Dynamic Excitations ◽  
Prediction Criteria ◽  
Linear Prediction Model ◽  
Good Agreement

Dynamic excitations in machines and structures may lead to a form of wear caused by the phenomenon of fretting, which may cause premature mechanical or structural failure. Fretting-wear has been evaluated under a variety of conditions, and a linear prediction model is compared to experimental results with good agreement.

scholarly journals A Peierls-Nabarro Model for Kink-Pair Generation in Screw Dislocations at Low Temperatures

1998 ◽  
Vol 538 ◽  
Author(s):  
A.H.W. Ngan
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Plane Strain ◽  
Low Temperatures ◽  
Screw Dislocations ◽  
Kink Pair ◽  
Bcc Lattice ◽  
Pair Generation ◽  
Experimental Findings ◽  
Good Agreement

AbstractKink-pair generation in three-fold screw dislocations in the bcc lattice is investigated within the framework of the generalised Peierls-Nabarro model. Using a piece-wise plane strain approximation, the apparent activation energy is predicted to vary with stress in a parabolic manner which is in good agreement with experimental findings.

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