Micro-thermal field-flow fractionation in the characterization of macromolecules and particles: Effect of the steric exclusion mechanism

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Josef Janča ◽  
Irina A. Ananieva
Keyword(s):  
Experimental Data ◽  
Thermal Field ◽  
Separation Mechanism ◽  
Particle Sizes ◽  
Field Flow Fractionation ◽  
Steric Exclusion ◽  
Extended Range ◽  
Exclusion Mechanism ◽  
Good Agreement

Abstract The influence of the steric exclusion mechanism on the dependence of the retention on the thickness of the micro-TFFF channel was studied theoretically. A good agreement of theory with experimental data was found. In order to preserve the use of micro-TFFF within an extended range of molar masses and particle sizes, the thickness of the channel cannot be reduced without taking into account a possible deterioration of the separation due to the contribution of steric exclusion to the separation mechanism.

A comparative study of lead adsorption by activated Khaya Ivoresnsis and Pycanthus Angolensis sawdust

2016 ◽  
Vol 6 (4) ◽  
pp. 593-601
Author(s):  
Chidozie Charles Nnaji ◽  
Stephen Chinwike Emefu
Keyword(s):  
Experimental Data ◽  
Freundlich Isotherm ◽  
Intraparticle Diffusion ◽  
Bulk Liquid ◽  
Timber Species ◽  
Particle Sizes ◽  
Lead Adsorption ◽  
Intraparticle Diffusion Model ◽  
First Order Kinetics ◽  
Good Agreement

Experiments investigating lead adsorption by activated sawdust of different particle sizes of two timber species were conducted. The experimental data were fitted to isothermal and kinetic models. The optimum particle size was 0.85 mm for Khaya ivorensis and 1.18 mm for Pycanthus angolensis. The adsorption of lead by Khaya ivorensis and Pycanthus angolensis conformed to the Langmuir isotherm (0.83 ≤ R2 ≤ 0.96 and 0.86 ≤ R2 ≤ 0.98, respectively) and Freundlich isotherm (0.69 ≤ R2 ≤ 0.97 and 0.94 ≤ R2 ≤ 1.0, respectively). The adsorption process for the two species of timber was controlled by solute transport in the bulk liquid and intraparticle diffusion which was confirmed by good agreement of experimental data with pseudo-first-order kinetics (0.96 ≤ R2 ≤ 1.0 for Khaya ivorensis and 0.9 ≤ R2 ≤ 1.0 for Pycanthus angolensis) and the intraparticle diffusion model (0.9 ≤ R2 ≤ 0.99 for Khaya ivorensis and 0.84 ≤ R2 ≤ 0.97 for Pycanthus angolensis). A new kinetic model was developed with R2 of 0.93 ≤ R2 ≤ 0.99 for Khaya ivorensis and 0.88 ≤ R2 ≤ 1.0 for Pycanthus angolensis.

Simulation and prediction of optical characterization of casting (Adamantan-Fulgide) thin films using (CTANNs) approach

2019 ◽  
Vol 33 (11) ◽  
pp. 1950093 ◽  
Author(s):  
A. M. A. EL-Barry ◽  
D. M. Habashy
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Back Propagation ◽  
Optical Characterization ◽  
Experimental Information ◽  
Training Algorithm ◽  
Energy Gaps ◽  
Resilient Back Propagation ◽  
Good Agreement

For reinforcement, the photochromic field and the cooperation between the theoretical and experimental branches of physics, the computational, theoretical artificial neural networks (CTANNs) and the resilient back propagation (R[Formula: see text]) training algorithm were used to model optical characterizations of casting (Admantan-Fulgide) thin films with different concentrations. The simulated values of ANN are in good agreement with the experimental data. The model was also used to predict values, which were not included in the training. The high precision of the model has been constructed. Moreover, the concentration dependence of both the energy gaps and Urbach’s tail were, also tested. The capability of the technique to simulate the experimental information with best accuracy and the foretelling of some concentrations which is not involved in the experimental data recommends it to dominate the modeling technique in casting (Admantan-Fulgide) thin films.

Simfuel Leaching Studies in Granitic Groundwater Under Oxidizing Conditions

1995 ◽  
Vol 412 ◽  
Author(s):  
J. Garcia-Serrano ◽  
J. A. Serrano ◽  
P. P. Diaz-Arocas ◽  
J. Quiñones ◽  
J. L. R. Almazan
Keyword(s):  
Elemental Analysis ◽  
Particle Sizes ◽  
Leaching Tests ◽  
Minor Components ◽  
High Release ◽  
Synthetic Groundwater ◽  
Granitic Groundwater ◽  
Good Agreement

AbstractSimulated high-bumup nuclear fuel (SIMFUEL) has been leached in synthetic groundwater under oxic conditions. SIMFUEL pellets were ground and sieved to two particle sizes (50–100 and 100–315 μm). An extensive solid characterization of the fragments was carried out by various techniques. Elemental analysis has also been performed prior to the leaching tests.The release of U and the minor components (Mo, Ba and Sr) was monitored during the long term dissolution experiments (350 days). These minor components exhibit a trend similar to uranium, high release at the beginning followed by a plateau. The M/U calculated ratios show different behavior although after a period of time, depending on the particle sizes, constant ratios were observed.SIMHUEL powder was used in order to simulate the physical effect of bum-up on the fuel structure. This fact seems to play an important role on the uranium release. A comparison with the results given in the literature for SIMFUEL pellet leaching tests shows good agreement with the values reported.

Characterization of effects of selected organic substances on decomposition of hydrogen peroxide during Fenton reaction

2004 ◽  
Vol 49 (4) ◽  
pp. 129-134 ◽  
Author(s):  
K.C. Namkung ◽  
A. Aris ◽  
P.N. Sharratt
Keyword(s):  
Experimental Data ◽  
Hydrogen Peroxide ◽  
Fenton Reaction ◽  
Reactive Black 5 ◽  
Organic Substances ◽  
Oxidation Model ◽  
Simulation Results ◽  
Good Agreement

This study aims to investigate the effects of selected organic substances on the degradation of hydrogen peroxide during the Fenton reaction. Since the presence of organic substances can strongly affect the mechanism of the Fenton reaction, the information on effects of organic substances on the reaction would be a vital guide to the success of its application to the destruction of organics in wastewater. Several organic compounds having different structures were selected as model pollutants: 4-chlorophenol, 1,4-dioxane, chloroform, a dye (reactive black-5), and EDTA. Oxidation of 4-chlorophenol and reactive black-5 resulted in enormously fast degradation of hydrogen peroxide, while others such as 1,4-dioxane and chloroform showed much slower degradation. These experimental data were compared to simulation results from a computational model based on a simple áOH-driven oxidation model. Modelling results for chloroform and 1,4-dioxane were in relatively good agreement with the experimental data, while those for 4-chlorophenol and reactive black-5 were very different from the experimental data. The results for EDTA showed a different trend to those for other compounds. From these results, classification of organic substances into several sub-groups was tried.

Thermal Field-Flow Fractionation for Characterization of Architecture in Hyperbranched Aromatic-Aliphatic Polyesters with Controlled Branching

2019 ◽  
Vol 91 (19) ◽  
pp. 12344-12351 ◽  
Author(s):  
William C. Smith ◽  
Martin Geisler ◽  
Albena Lederer ◽  
S. Kim Ratanathanawongs Williams
Keyword(s):  
Thermal Field ◽  
Field Flow Fractionation ◽  
Aliphatic Polyesters ◽  
Flow Fractionation
Sign in / Sign up

Export Citation Format

Share Document