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1D Measurement of Sodium Ion Flow in Hydrogel After a Bath Concentration Jump.

Roos RW, Pel L, Huinink HP, Huyghe JM - Ann Biomed Eng (2015)

Bottom Line: Then a reversed step is applied, and ion flow is measured for another 5 days.During the measurement, the cylindrical sample is radially confined and allowed to swell in the axial direction.The best fit results were obtained for D[Formula: see text] cm(2)/s and D[Formula: see text] cm(2)/s, at 25 degrees centigrade.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands, rroos@gmail.com.

ABSTRACT
NMR is used to measure sodium flow driven by a 1D concentration gradient inside poly-acrylamid (pAA) hydrogel. A sodium concentration jump from 0.5 M NaCl to 0 M NaCl is applied at the bottom of a cylindrical pAA sample. The sodium level and hydrogen level are measured as a function of time and position inside the sample for 5 days. Then a reversed step is applied, and ion flow is measured for another 5 days. During the measurement, the cylindrical sample is radially confined and allowed to swell in the axial direction. At the same time, sodium and moisture in the sample are measured on a 1D spatial grid in the axial direction. A quadriphasic mixture model (Huyghe and Janssen in Int J Eng Sci 35:793, 1997) is used to simulate the results and estimate the diffusion coefficient of sodium and chloride. The best fit results were obtained for D[Formula: see text] cm(2)/s and D[Formula: see text] cm(2)/s, at 25 degrees centigrade. Different time constants were observed for swelling and deswelling.

No MeSH data available.


Related in: MedlinePlus

The course of sodium profiles (top) and hydrogen profiles (bottom) during the swelling period (Fig. 2). The profiles are constructed from an interpolation of the raw data at an equidistant time grid. Exchange of water and sodium between the pAA sample and the external reservoir only occurs via the bottom of the sample at . The variation of the hydrogen signal during the swelling period is less than 5%.
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Fig3: The course of sodium profiles (top) and hydrogen profiles (bottom) during the swelling period (Fig. 2). The profiles are constructed from an interpolation of the raw data at an equidistant time grid. Exchange of water and sodium between the pAA sample and the external reservoir only occurs via the bottom of the sample at . The variation of the hydrogen signal during the swelling period is less than 5%.

Mentions: 1D transport of sodium through radially confined pAA samples is caused by a bath concentration jump at one end of the sample. This process is accompanied by sample swelling. Subsequent measurements series of and are done on a spatial grid in the axial direction. Each measurement series takes 3 hours, which is a long period compared to the sodium diffusion rate in pAA. Therefore, time profiles are calculated by interpolation of raw data on an equidistant time grid to give an unambiguous representation of the measured sodium diffusion. The results for the swelling period are displayed in Fig. 3 and for the deswelling period in Fig. 4.


1D Measurement of Sodium Ion Flow in Hydrogel After a Bath Concentration Jump.

Roos RW, Pel L, Huinink HP, Huyghe JM - Ann Biomed Eng (2015)

The course of sodium profiles (top) and hydrogen profiles (bottom) during the swelling period (Fig. 2). The profiles are constructed from an interpolation of the raw data at an equidistant time grid. Exchange of water and sodium between the pAA sample and the external reservoir only occurs via the bottom of the sample at . The variation of the hydrogen signal during the swelling period is less than 5%.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4495263&req=5

Fig3: The course of sodium profiles (top) and hydrogen profiles (bottom) during the swelling period (Fig. 2). The profiles are constructed from an interpolation of the raw data at an equidistant time grid. Exchange of water and sodium between the pAA sample and the external reservoir only occurs via the bottom of the sample at . The variation of the hydrogen signal during the swelling period is less than 5%.
Mentions: 1D transport of sodium through radially confined pAA samples is caused by a bath concentration jump at one end of the sample. This process is accompanied by sample swelling. Subsequent measurements series of and are done on a spatial grid in the axial direction. Each measurement series takes 3 hours, which is a long period compared to the sodium diffusion rate in pAA. Therefore, time profiles are calculated by interpolation of raw data on an equidistant time grid to give an unambiguous representation of the measured sodium diffusion. The results for the swelling period are displayed in Fig. 3 and for the deswelling period in Fig. 4.

Bottom Line: Then a reversed step is applied, and ion flow is measured for another 5 days.During the measurement, the cylindrical sample is radially confined and allowed to swell in the axial direction.The best fit results were obtained for D[Formula: see text] cm(2)/s and D[Formula: see text] cm(2)/s, at 25 degrees centigrade.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands, rroos@gmail.com.

ABSTRACT
NMR is used to measure sodium flow driven by a 1D concentration gradient inside poly-acrylamid (pAA) hydrogel. A sodium concentration jump from 0.5 M NaCl to 0 M NaCl is applied at the bottom of a cylindrical pAA sample. The sodium level and hydrogen level are measured as a function of time and position inside the sample for 5 days. Then a reversed step is applied, and ion flow is measured for another 5 days. During the measurement, the cylindrical sample is radially confined and allowed to swell in the axial direction. At the same time, sodium and moisture in the sample are measured on a 1D spatial grid in the axial direction. A quadriphasic mixture model (Huyghe and Janssen in Int J Eng Sci 35:793, 1997) is used to simulate the results and estimate the diffusion coefficient of sodium and chloride. The best fit results were obtained for D[Formula: see text] cm(2)/s and D[Formula: see text] cm(2)/s, at 25 degrees centigrade. Different time constants were observed for swelling and deswelling.

No MeSH data available.


Related in: MedlinePlus