Soret coefficient and heat transport of aqueous solutions of cadmium sulphate

1963 ◽  
Vol 59 ◽  
pp. 2268 ◽  
Author(s):  
J. Demichowicz-Pigoniowa
Keyword(s):  
Aqueous Solutions ◽  
Heat Transport ◽  
Soret Coefficient

Thermal Diffusion of Weak Electrolytes III. The Soret Coefficients of Normal Carboxylic Acids

2000 ◽  
Vol 214 (1) ◽  
Author(s):  
L. Domonkos ◽  
J. Liszi
Keyword(s):  
Formic Acid ◽  
Aqueous Solutions ◽  
Carboxylic Acids ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Conductometric Method ◽  
New Model ◽  
Weak Electrolytes

A conductometric method is described and applied for the determination of the Soret coefficient of normal carboxylic acids in aqueous solutions in order to check a new model described in our previous papers. The Soret cell originally developed by Agar and Turner was applied with only minor modifications. The results show that the deviations between the measured and calculated Soret coefficients are lower than 2.5% except for formic acid (33% in average).

Thermal diffusion with hydrolysis in aqueous solutions of sodium carbonate

1991 ◽  
Vol 69 (10) ◽  
pp. 1584-1588 ◽  
Author(s):  
Hui Lü ◽  
Derek G. Leaist
Keyword(s):  
Steady State ◽  
Aqueous Solutions ◽  
Thermal Diffusion ◽  
Sodium Carbonate ◽  
Soret Coefficient ◽  
Mixed Electrolytes ◽  
Cold Plate ◽  
Aqueous Sodium ◽  
Aqueous Sodium Carbonate ◽  
Nonisothermal Conditions

A conductimetric technique is used to measure thermal diffusion in aqueous solutions of sodium carbonate. In dilute solutions hydrolysis produces significant amounts of sodium bicarbonate and sodium hydroxide: Na2CO3 + H2O = NaHCO3 + NaOH. The applied temperature gradient causes the various solutes to migrate to the cooler parts of the solution. NaOH is found to diffuse more rapidly than NaHCO3, leading to the accumulation of excess NaOH (relative to NaHCO3) at the cold plate. Binary Na2CO3(m) + H2O mixtures therefore separate into ternary Na2CO3(m1) + NaOH(m2) + H2O mixtures under nonisothermal conditions. The steady-state molality gradients dm1/dT and dm2/dT and the ternary heats of transport of aqueous Na2CO3 and NaOH are reported. Key words: aqueous sodium carbonate, hydrolysis, mixed electrolytes, Soret coefficient, thermal diffusion.

scholarly journals A Molecular Dynamics Approach to Calculate the Thermodiffusion (Soret and Seebeck) Coefficients of Salts in Aqueous Solutions

2021 ◽  
Author(s):  
Leandro Rezende Franco ◽  
André Luiz Sehnem ◽  
Antônio Martins Figueiredo Neto ◽  
Kaline Coutinho
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Aqueous Solutions ◽  
Optical Measurements ◽  
Soret Coefficient ◽  
System Response ◽  
Physical Parameters ◽  
Hydration Free Energy ◽  
Self Diffusion ◽  
Seebeck Coefficients

<div><div><div><p>An approach to investigate the physical parameters related to the ions thermodiffusion in aqueous solution is proposed herein by calculating the equilibrium hydration free energy and the self-diffusion coefficient as a function of temperature, ranging from 293 to 353 K, using molecular dynamics simulations of infinitely diluted ions in aqueous solutions. Several ion force field parameters are used in the simulations and new parameters are proposed for some ions to better describe their hydration free energy. Such a theoretical framework enables the calculation of some single-ion properties, such as heat of transport, Soret coefficient and mass current density, as well as properties of salts, such as effective mass and thermal diffusion, Soret and Seebeck coefficients. These calculated properties are compared with experimental data available from optical measurements and showed good agreement revealing an excellent theoretical predictability of salt thermodiffusion properties. Differences in single-ion Soret and self-diffusion coefficients of anions and cations give rise to a thermoelectric field, which affects the system response that is quantified by the Seebeck coefficient. The fast and slow Seebeck coefficients are calculated and discussed, resulting in values with mV/K order-of-magnitude, as observed in experiments involving several salts, such as K+Cl−, Na+Cl−, H+Cl−, Na+OH−, TMA+OH− and TBA+OH−. The present approach can be adopted for any ion or charged particle dispersed in water with the aim of predicting the thermoelectric field induced through the fluid. It has potential applications in designing electrolytes for ionic thermoelectric devices in order to harvest energy and thermoelectricity in biological nanofluids.</p></div></div></div>

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 The role of ion–water interactions in determining the Soret coefficient of LiCl aqueous solutions

2017 ◽  
Vol 19 (14) ◽  
pp. 9575-9583 ◽  
Author(s):  
Silvia Di Lecce ◽  
Tim Albrecht ◽  
Fernando Bresme
Keyword(s):  
Aqueous Solutions ◽  
Soret Coefficient ◽  
Solvation Structure

The solvation structure of Li+ plays a key role in determining the Soret coefficient of LiCl aqueous solutions.

scholarly journals A Molecular Dynamics Approach to Calculate the Thermodiffusion (Soret and Seebeck) Coefficients of Salts in Aqueous Solutions

2021 ◽  
Author(s):  
Leandro Rezende Franco ◽  
André Luiz Sehnem ◽  
Antônio Martins Figueiredo Neto ◽  
Kaline Coutinho
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Aqueous Solutions ◽  
Optical Measurements ◽  
Soret Coefficient ◽  
System Response ◽  
Physical Parameters ◽  
Hydration Free Energy ◽  
Self Diffusion ◽  
Seebeck Coefficients

<div><div><div><p>An approach to investigate the physical parameters related to the ions thermodiffusion in aqueous solution is proposed herein by calculating the equilibrium hydration free energy and the self-diffusion coefficient as a function of temperature, ranging from 293 to 353 K, using molecular dynamics simulations of infinitely diluted ions in aqueous solutions. Several ion force field parameters are used in the simulations and new parameters are proposed for some ions to better describe their hydration free energy. Such a theoretical framework enables the calculation of some single-ion properties, such as heat of transport, Soret coefficient and mass current density, as well as properties of salts, such as effective mass and thermal diffusion, Soret and Seebeck coefficients. These calculated properties are compared with experimental data available from optical measurements and showed good agreement revealing an excellent theoretical predictability of salt thermodiffusion properties. Differences in single-ion Soret and self-diffusion coefficients of anions and cations give rise to a thermoelectric field, which affects the system response that is quantified by the Seebeck coefficient. The fast and slow Seebeck coefficients are calculated and discussed, resulting in values with mV/K order-of-magnitude, as observed in experiments involving several salts, such as K+Cl−, Na+Cl−, H+Cl−, Na+OH−, TMA+OH− and TBA+OH−. The present approach can be adopted for any ion or charged particle dispersed in water with the aim of predicting the thermoelectric field induced through the fluid. It has potential applications in designing electrolytes for ionic thermoelectric devices in order to harvest energy and thermoelectricity in biological nanofluids.</p></div></div></div>

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Imaging polymers, proteins and dna in aqueous solutions with the atomic force microscope

1989 ◽  
Vol 47 ◽  
pp. 32-33
Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Sequencing ◽  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Piezoelectric Crystal ◽  
Atomic Force ◽  
Structure Of Molecules ◽  
Optical Lever

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.

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