Mathematical modeling and experimental investigation of the effect of temperature gradients on crystallization processes under terrestrial and space conditions

2005 ◽  
Vol 50 (3) ◽  
pp. 490-498 ◽  
Author(s):  
V. I. Strelov ◽  
B. G. Zakharov ◽  
V. S. Sidorov ◽  
I. Zh. Bezbakh ◽  
V. I. Folomeev
Keyword(s):  
Mathematical Modeling ◽  
Experimental Investigation ◽  
Temperature Gradients ◽  
Effect Of Temperature ◽  
Space Conditions

Thermorheological Characterization of Elastoviscoplastic Carbopol Ultrez 20 Gel

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. A. Hassan ◽  
Manabendra Pathak ◽  
Mohd. Kaleem Khan
Keyword(s):  
Experimental Investigation ◽  
Yield Stress ◽  
Elastic Properties ◽  
Viscous Dissipation ◽  
Power Law ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Frequency Range ◽  
Power Law Index

The temperature and concentration play an important role on rheological parameters of the gel. In this work, an experimental investigation of thermorheological properties of aqueous gel Carbopol Ultrez 20 for various concentrations and temperatures has been presented. Both controlled stress ramps and controlled stress oscillatory sweeps were performed for obtaining the rheological data to find out the effect of temperature and concentration. The hysteresis or thixotropic seemed to have negligible effect. Yield stress, consistency factor, and power law index were found to vary with temperature as well as concentration. With gel concentration, the elastic effect was found to increase whereas viscous dissipation effect was found to decrease. Further, the change in elastic properties was insignificant with temperature in higher frequency range of oscillatory stress sweeps.

scholarly journals Effect of temperature gradients in (reverse) electrodialysis in the Ohmic regime

2018 ◽  
Vol 548 ◽  
pp. 421-428 ◽  
Author(s):  
Anne M. Benneker ◽  
Timon Rijnaarts ◽  
Rob G.H. Lammertink ◽  
Jeffery A. Wood
Keyword(s):  
Temperature Gradients ◽  
Effect Of Temperature ◽  
Reverse Electrodialysis

Experimental investigation and mathematical modeling of triode PEM fuel cells

2017 ◽  
Vol 248 ◽  
pp. 518-533 ◽  
Author(s):  
E. Martino ◽  
G. Koilias ◽  
M. Athanasiou ◽  
A. Katsaounis ◽  
Y. Dimakopoulos ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Experimental Investigation ◽  
Fuel Cells ◽  
Pem Fuel Cells

scholarly journals Cardiac Spiral Wave Drifting Due to Spatial Temperature Gradients – a Numerical Study

2018 ◽  
Author(s):  
Guy Malki ◽  
Sharon Zlochiver
Keyword(s):  
Numerical Simulations ◽  
Single Cell ◽  
Numerical Study ◽  
Spiral Wave ◽  
Spiral Waves ◽  
Temperature Gradients ◽  
Effect Of Temperature ◽  
Local Perturbation ◽  
Marginal Effect ◽  
Spatial Temperature

ABSTRACTCardiac rotors are believed to be a major driver source of persistent atrial fibrillation (AF), and their spatiotemporal characterization is essential for successful ablation procedures. However, electrograms guided ablation have not been proven to have benefit over empirical ablation thus far, and there is a strong need of improving the localization of cardiac arrhythmogenic targets for ablation. A new approach for characterize rotors is proposed that is based on induced spatial temperature gradients (STGs), and investigated by theoretical study using numerical simulations. We hypothesize that such gradients will cause rotor drifting due to induced spatial heterogeneity in excitability, so that rotors could be driven towards the ablating probe. Numerical simulations were conducted in single cell and 2D atrial models using AF remodeled kinetics. STGs were applied either linearly on the entire tissue or as a small local perturbation, and the major ion channel rate constants were adjusted following Arrhenius equation. In the AF-remodeled single cell, recovery time increased exponentially with decreasing temperatures, despite the marginal effect of temperature on the action potential duration. In 2D models, spiral waves drifted with drifting velocity components affected by both temperature gradient direction and the spiral wave rotation direction. Overall, spiral waves drifted towards the colder tissue region associated with global minimum of excitability. A local perturbation with a temperature of T=28°C was found optimal for spiral wave attraction for the studied conditions. This work provides a preliminary proof-of-concept for a potential prospective technique for rotor attraction. We envision that the insights from this study will be utilize in the future in the design of a new methodology for AF characterization and termination during ablation procedures.

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