Determination of Diffusion Coefficient of Carbon Dioxide in Polyethylene by the Method of Moments

1993 ◽  
Vol 58 (2) ◽  
pp. 252-258 ◽  
Author(s):  
Jan Jirásek ◽  
Milan Šípek
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Diffusion Coefficient ◽  
Method Of Moments ◽  
Diffusion Coefficients ◽  
Optimization Method ◽  
Diffusion Equations ◽  
High Pressure Polyethylene ◽  
Good Agreement

By using the method of moments, the values of diffusion coefficients of carbon dioxide in high-pressure polyethylene of two different thicknesses were determined at 25 °C. The values of diffusion coefficients determined with the accuracy of about ±3% are in good agreement both with the values obtained by the optimization method, and with the published values determined on the basis of asymptotic solutions of diffusion equations.

Molten Slag Structure and Diffusion Coefficients of Cr3+ and Si4+ during Micro-Carbon Cr-Fe Alloy Production

2011 ◽  
Vol 79 ◽  
pp. 77-82
Author(s):  
Yi Min ◽  
Jian Huang ◽  
Cheng Jun Liu ◽  
Mao Fa Jiang
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Molten Slag ◽  
Optimization Method ◽  
Structure Theory ◽  
Average Diffusion Coefficient ◽  
Slag Structure ◽  
Initial Stage ◽  
Silicate Structure ◽  
Average Diffusion

Based on the silicate structure theory, the molten slag structure and the existential state of and during micro-carbon Cr-Fe alloy production process were analysised, and then their diffusion coefficients were calculated. The results showed that, during the initial stage, the average diffusion coeffecient of and is close to the , the reaction process is controlled by the diffusion of () and corporately, during the later stage, the diffusion coefficient of is less than average diffusion coefficient of and , the controlling step is the diffusion of . According to the evolution of diffusion coefficient, molten slag composition optimization method was advised to increase the diffusion ability of and for enhancing the reaction efficiency and the recovery rate of chromium.

Determination of Uncombined Intermediates in FD&C Yellow No. 6 by High-Pressure Liquid Chromatography

1974 ◽  
Vol 57 (2) ◽  
pp. 358-359
Author(s):  
Manjeet Singh
Keyword(s):  
High Pressure ◽  
Chromatographic Method ◽  
Sulfanilic Acid ◽  
Sunset Yellow ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Two Samples ◽  
Liquid Chromatographic ◽  
Good Agreement

Abstract A high-pressure liquid chromatographic method is presented for the isolation and determination of uncombined intermediates in FD&C Yellow No. 6 (sunset yellow FCF, CI. No. 15895). Samples of FD&C Yellow No. 6 containing 0.1-0.4% sulfanilic acid, 0.1-0.4% 6-hydroxy-2-naphthalenesulfonic acid, and 0.3— 1.0% 6,6'-oxybis(2-naphthalenesulfonic acid) were prepared and analyzed using this method. Recoveries ranged between 94 and 101%. Twenty-two samples of FD&C Yellow No. 6 were analyzed by the conventional column elution chromatographic method as well as by the high-pressure liquid chromatographic method. Good agreement was obtained between the 2 methods.

scholarly journals Determination of Diffusion Coefficients Using Thermogravimetric Measurements during High Temperature Oxidation

2012 ◽  
Vol 323-325 ◽  
pp. 289-294
Author(s):  
Patrice Berthod ◽  
Lionel Aranda
Keyword(s):  
Diffusion Coefficient ◽  
High Temperature ◽  
Diffusion Coefficients ◽  
High Temperature Oxidation ◽  
Concentration Profiles ◽  
Metallic Elements ◽  
Chromium Diffusion ◽  
Temperature Oxidation ◽  
Iron Based

Thermogravimetry measurements associated to concentration profiles allow determining a diffusion coefficient at high temperature of the most oxidable one among the metallic elements belonging to the chemical composition of an alloy. In this work the employed method is described and applied to chromia-forming alloys essentially based on nickel but also to selected cobalt-based and iron-based alloys. More precisely DCrvalues were estimated for chromium diffusing through the carbide-free zones developed during high temperature oxidation. The effects of the base element, of the chromium carbides density and of the dendritic orientations on the chromium diffusion were evidenced.

Measurement of diffusion coefficients

1954 ◽  
Vol 222 (1148) ◽  
pp. 109-118 ◽  
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Liquid Solution ◽  
Constant Volume ◽  
Diffusion Equations ◽  
Sorption Coefficient ◽  
Rapid Methods ◽  
Error Functions ◽  
Volume Method

For diffusion into a solid from a gas or a liquid solution, the constant-volume method of measuring the diffusion coefficient has distinct experimental advantages. The diffusion equations required are summarized in the present paper and their application is illustrated by typical experiments. To reduce the amount of computation, equations involving error functions have been derived for application to the first stages of a diffusion run, When the diffusion coefficient and/or the sorption coefficient are concentration dependent, the equations in this paper are still applicable if sorption is carried out in suitably chosen steps. When sorption takes place only at the two parallel faces of a slab (film, sheet or plug), simple and rapid methods of calculating D can be used.

Computer-based system for analysis of respiratory responses to exercise

1977 ◽  
Vol 42 (6) ◽  
pp. 968-975 ◽  
Author(s):  
D. H. Pearce ◽  
H. T. Milhorn ◽  
G. H. Holloman ◽  
W. J. Reynolds
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Exchange Ratio ◽  
Minute Ventilation ◽  
Type System ◽  
Work Load ◽  
Magnetic Type ◽  
Computer Based ◽  
End Tidal ◽  
Good Agreement

A computer-based system for the determination of tidal volume, respiratory frequency, minute ventilation, oxygen transfer, carbon dioxide transfer, respiratory exchange ratio, end-tidal oxygen, end-tidal carbon dioxide, and heart rate is presented. These variables are first determined on a breath-by-breath basis from data (expired carbon dioxide and oxygen fractions, airflow, and ECG) prerecorded on an FM magnetic type system. The breath-by-breath data are then averaged for each experimental run in 5-s increments. The 5-s increment data from a group of subjects can then be averaged and the SEM determined at prescribed periods of time. For the study of individual respiratory transient we found the 5-s increment data to be more useful than the breath-by-breath data because it has a lesser degree of fluctuation. The system is especially adapted to careful observation of the responses within the first few seconds of a change in work load. Appropriate computer programs are discussed. The results of several experiments are compared with data from other sources and found to be in good agreement.

The Concentration Dependence at 1 atm Pressure and 300 °K of the Binary Diffusion Coefficients of the Systems Helium – Carbon Dioxide, Helium – Nitrous Oxide, and Helium – Sulfur Hexafluoride

1972 ◽  
Vol 50 (12) ◽  
pp. 1874-1876 ◽  
Author(s):  
Kenneth R. Harris ◽  
T. N. Bell ◽  
Peter J. Dunlop
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Diffusion Coefficient ◽  
Concentration Dependence ◽  
Mole Fraction ◽  
Diffusion Coefficients ◽  
Sulfur Hexafluoride ◽  
Enskog Theory ◽  
Binary Diffusion ◽  
Binary Diffusion Coefficients

Binary diffusion coefficients are reported for the systems He–CO2, He–N2O, and He–SF6. In agreement with the Chapman–Enskog theory the concentration dependence of the diffusion coefficient of each system increases with the mole fraction of the heavier component.

scholarly journals Phase Behavior at High Pressure of the Ternary System: CO2, Ionic Liquid and Disperse Dye

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Helen R. Mazzer ◽  
José C. O. Santos ◽  
Vladimir F. Cabral ◽  
Claudio Dariva ◽  
Marcos H. Kunita ◽  
...  
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
High Pressure ◽  
Phase Behavior ◽  
Ternary Systems ◽  
High Pressure Phase Behavior ◽  
Phase Transition Pressure ◽  
Binary And Ternary Systems ◽  
Pressure Phase ◽  
Good Agreement

High pressure phase behavior experimental data have been measured for the systems carbon dioxide (CO2) + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6]) and carbon dioxide (CO2) + 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6]) + 1-amino-2-phenoxy-4-hydroxyanthraquinone (C.I. Disperse Red 60). Measurements were performed in the pressure up to 18 MPa and at the temperature (323 to 353 K). As reported in the literature, at higher concentrations of carbon dioxide the phase transition pressure increased very steeply. The experimental data for the binary and ternary systems were correlated with good agreement using the Peng-Robinson equation of state. The amount of water in phase behavior of the systems was evaluated.

Sign in / Sign up

Export Citation Format

Share Document