scholarly journals Thermophoresis: The Case of Streptavidin and Biotin

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 376 ◽  
Author(s):  
Doreen Niether ◽  
Mona Sarter ◽  
Bernd W. Koenig ◽  
Jörg Fitter ◽  
Andreas M. Stadler ◽  
...  
Keyword(s):  
Heavy Water ◽  
Rayleigh Scattering ◽  
Soret Effect ◽  
Binding Constants ◽  
Soret Coefficient ◽  
Protein Solutions ◽  
Elastic Neutron ◽  
Solvent Interactions ◽  
Free Protein ◽  
Promising Tool

Thermophoretic behavior of a free protein changes upon ligand binding and gives access to information on the binding constants. The Soret effect has also been proven to be a promising tool to gain information on the hydration layer, as the temperature dependence of the thermodiffusion behavior is sensitive to solute–solvent interactions. In this work, we perform systematic thermophoretic measurements of the protein streptavidin (STV) and of the complex STV with biotin (B) using thermal diffusion forced Rayleigh scattering (TDFRS). Our experiments show that the temperature sensitivity of the Soret coefficient is reduced for the complex compared to the free protein. We discuss our data in comparison with recent quasi-elastic neutron scattering (QENS) measurements. As the QENS measurement has been performed in heavy water, we perform additional measurements in water/heavy water mixtures. Finally, we also elucidate the challenges arising from the quantiative thermophoretic study of complex multicomponent systems such as protein solutions.

The Soret Effect: A Review of Recent Experimental Results

2005 ◽  
Vol 73 (1) ◽  
pp. 5-15 ◽  
Author(s):  
Jean K. Platten
Keyword(s):  
Rayleigh Scattering ◽  
Soret Effect ◽  
Organic Liquid ◽  
Oil Industry ◽  
Liquid Mixtures ◽  
Beam Deflection ◽  
Soret Coefficient ◽  
Onset Of Convection ◽  
New Techniques ◽  
Scattering Technique

In the first part of the paper, we recall what the Soret effect is, together with its applications in science and industry. We emphasize the need to have a reliable data base for the Soret coefficient. Next we review the different techniques to measure the Soret coefficient (elementary Soret cell, beam deflection technique, thermal diffusion forced Rayleigh scattering technique, convective coupling and, in particular, the onset of convection in horizontal layers and the thermogravitational method). Results are provided for several systems, with both negative and positive Soret coefficients, and comparison between several laboratories are made for the same systems. We end with “benchmark” values of the Soret coefficient for some organic liquid mixtures of interest in the oil industry and to which all future new techniques should refer before gaining confidence. We conclude that correct values of the Soret coefficient can be obtained in earth conditions and we deny the need to go to microgravity.

Numerical Analysis of Thermal-Solutal Convection in Heterogeneous Porous Media

2005 ◽  
Vol 73 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Charles-Guobing Jiang ◽  
M. Ziad Saghir ◽  
M. Kawaji
Keyword(s):  
Porous Media ◽  
Thermal Diffusion ◽  
Soret Effect ◽  
Heterogeneous Porous Media ◽  
Soret Coefficient ◽  
Solutal Convection ◽  
Coefficient Distribution ◽  
Separation Ratio ◽  
Diffusion In Porous Media ◽  
Vertical Cavity

Thermal diffusion, or Soret effect, in porous media is mathematically modeled with the Firoozabadi model based on non-equilibrium thermodynamics. The Soret effect in a binary mixture is investigated in a vertical cavity with heterogeneous permeability, where natural convection can occur. The thermo solutal convection with heterogeneous permeability was studied in terms of flow pattern, concentration distribution, component separation ratio, and Soret coefficient distribution. A consistent analysis was conducted and it is concluded that the Soret coefficient of thermal diffusion in porous media strongly depends on the heterogeneity of permeability.

Thermophoresis as a probe of particle–solvent interactions: The case of protein solutions

2004 ◽  
Vol 6 (7) ◽  
pp. 1616-1622 ◽  
Author(s):  
Roberto Piazza ◽  
Sara Iacopini ◽  
Benedetta Triulzi
Keyword(s):  
Protein Solutions ◽  
Solvent Interactions

scholarly journals Marangoni convection in binary mixtures with Soret effect

1998 ◽  
Vol 375 ◽  
pp. 143-177 ◽  
Author(s):  
A. BERGEON ◽  
D. HENRY ◽  
H. BENHADID ◽  
L. S. TUCKERMAN
Keyword(s):  
Marangoni Convection ◽  
Soret Effect ◽  
Spectral Element ◽  
Soret Coefficient ◽  
Small Range ◽  
Concentration Gradients ◽  
Time Stepping ◽  
Pure Fluid ◽  
Secondary Bifurcations ◽  
Steady Convection

Marangoni convection in a differentially heated binary mixture is studied numerically by continuation. The fluid is subject to the Soret effect and is contained in a two-dimensional small-aspect-ratio rectangular cavity with one undeformable free surface. Either or both of the temperature and concentration gradients may be destabilizing; all three possibilities are considered. A spectral-element time-stepping code is adapted to calculate bifurcation points and solution branches via Newton's method. Linear thresholds are compared to those obtained for a pure fluid. It is found that for large enough Soret coefficient, convection is initiated predominantly by solutal effects and leads to a single large roll. Computed bifurcation diagrams show a marked transition from a weakly convective Soret regime to a strongly convective Marangoni regime when the threshold for pure fluid thermal convection is passed. The presence of many secondary bifurcations means that the mode of convection at the onset of instability is often observed only over a small range of Marangoni number. In particular, two-roll states with up-flow at the centre succeed one-roll states via a well-defined sequence of bifurcations. When convection is oscillatory at onset, the limit cycle is quickly destroyed by a global (infinite-period) bifurcation leading to subcritical steady convection.

A Model of Flow in a Closed-Loop Thermosyphon Including the Soret Effect

1985 ◽  
Vol 107 (4) ◽  
pp. 840-849 ◽  
Author(s):  
J. E. Hart
Keyword(s):  
Rayleigh Number ◽  
Soret Effect ◽  
Vertical Plane ◽  
Soret Coefficient ◽  
Chaotic Motions ◽  
Thermohaline Convection ◽  
Existence And Stability ◽  
Convective Motions ◽  
Steady Solutions ◽  
Set Up

This theoretical study addresses the nature of convective motions in a toroidal loop of binary fluid oriented in the vertical plane and heated from below. The boundaries of the loop are impermeable, but gradients of the solute can be set up by Soret diffusion in the direction around the loop. The existence and stability of steady solutions are discussed over the Rayleigh number-Soret coefficient parameter plane. When the Soret coefficient is negative, periodic and chaotic oscillations analogous to those of thermohaline convection are predicted. When the Soret coefficient is positive, relaxation oscillations and low Rayleigh number chaotic motions are found. Both sets of phenomena are predicted to occur for realistic thermosyphon parameters.

scholarly journals Natural Convection And Soret Effect In A Multi-Layered Liquid And Porous System

2021 ◽  
Author(s):  
Hussam K. Jawad
Keyword(s):  
Natural Convection ◽  
Opposite Sign ◽  
Soret Effect ◽  
Fluid Mixing ◽  
Soret Coefficient ◽  
Hydrocarbon Mixture ◽  
Porous System ◽  
Layer System ◽  
Separation Ratio ◽  
Water Alcohol

We investigated the onset of natural convection and thermodiffusion in an initially quiescent multi-layer system consisting of a porous layer sandwiched between two layers of a binary mixture, while the whole system is being heated from above. Two different water-alcohol mixtures were used with Soret coefficients of opposite sign. Then in similar situation a hydrocarbon mixture were investigated. It was found that when the Soret coefficient is negative, the lighter species migrates towards the colder surface while the denser species migrates towards the hotter surface. When the Soret coefficient is positive, the lighter species migrates towards the hotter surface while the denser species migrates towards the colder surface. Also, increasing the temperature difference leads to a greater separation of the mixture components because of the increase in the density gradient. In addition, increasing the porosity reduces the separation ratio due to the increased fluid mixing in the pores.

Thermal diffusion of aqueous alcohols

1989 ◽  
Vol 67 (5) ◽  
pp. 867-870
Author(s):  
Ashis Kumar Mukherjee ◽  
S. K. Sanyal
Keyword(s):  
Aqueous Solutions ◽  
Temperature Coefficient ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Local Entropy ◽  
Solvent Interactions ◽  
Solvent Water ◽  
Heat Of Transport ◽  
Sintered Glass ◽  
Experimental Values

The thermal diffusion of aqueous solutions of methanol, ethanol, propan-1-ol, butan-1-ol, ethan-1,2-diol, andpropan-1,2-diol contained in the pores of a sintered glass disc (of porosity G4) has been studied. The Soret coefficient (σ) and the heat of transport [Formula: see text] values are reported in the temperature range of 25–40 °C. The heat capacities of transport are ascertained at 30 °C from the temperature coefficient of heat of transport values. The results are explained on the basis of changes in local entropy in the solvent (water), arising out of solute–solvent interactions. Correlations of the observed experimental values with certain relevant thermodynamic parameters, taken from the literature, have also been sought, with encouraging results. Keywords: thermal diffusion, heat of transport, entropy of hydration.

scholarly journals Natural Convection And Soret Effect In A Multi-Layered Liquid And Porous System

2021 ◽  
Author(s):  
Hussam K. Jawad
Keyword(s):  
Natural Convection ◽  
Opposite Sign ◽  
Soret Effect ◽  
Fluid Mixing ◽  
Soret Coefficient ◽  
Hydrocarbon Mixture ◽  
Porous System ◽  
Layer System ◽  
Separation Ratio ◽  
Water Alcohol

We investigated the onset of natural convection and thermodiffusion in an initially quiescent multi-layer system consisting of a porous layer sandwiched between two layers of a binary mixture, while the whole system is being heated from above. Two different water-alcohol mixtures were used with Soret coefficients of opposite sign. Then in similar situation a hydrocarbon mixture were investigated. It was found that when the Soret coefficient is negative, the lighter species migrates towards the colder surface while the denser species migrates towards the hotter surface. When the Soret coefficient is positive, the lighter species migrates towards the hotter surface while the denser species migrates towards the colder surface. Also, increasing the temperature difference leads to a greater separation of the mixture components because of the increase in the density gradient. In addition, increasing the porosity reduces the separation ratio due to the increased fluid mixing in the pores.

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