Dynamics of ionic liquids in bulk and in confinement by means of 1H NMR relaxometry – BMIM-OcSO4 in an SiO2 matrix as an example

2016 ◽  
Vol 18 (33) ◽  
pp. 23184-23194 ◽  
Author(s):  
Danuta Kruk ◽  
Milosz Wojciechowski ◽  
Szczepan Brym ◽  
Rajendra Kumar Singh

1H spin–lattice nuclear magnetic resonance relaxometry is applied to reveal the mechanisms of the ionic dynamics of BMIM-OcSO4 in bulk and in SiO2 nano-confinement.

2021 ◽  
Vol 327 ◽  
pp. 106976
Author(s):  
Danuta Kruk ◽  
Małgorzata Florek-Wojciechowska ◽  
Mecit Oztop ◽  
Esmanur Ilhan ◽  
Zbigniew Wieczorek

2021 ◽  
Vol 7 (2) ◽  
pp. 18
Author(s):  
Germana Landi ◽  
Fabiana Zama ◽  
Villiam Bortolotti

This paper is concerned with the reconstruction of relaxation time distributions in Nuclear Magnetic Resonance (NMR) relaxometry. This is a large-scale and ill-posed inverse problem with many potential applications in biology, medicine, chemistry, and other disciplines. However, the large amount of data and the consequently long inversion times, together with the high sensitivity of the solution to the value of the regularization parameter, still represent a major issue in the applicability of the NMR relaxometry. We present a method for two-dimensional data inversion (2DNMR) which combines Truncated Singular Value Decomposition and Tikhonov regularization in order to accelerate the inversion time and to reduce the sensitivity to the value of the regularization parameter. The Discrete Picard condition is used to jointly select the SVD truncation and Tikhonov regularization parameters. We evaluate the performance of the proposed method on both simulated and real NMR measurements.


2017 ◽  
Vol 32 (3) ◽  
pp. 242-249 ◽  
Author(s):  
Salvatore Gallo ◽  
Giorgio Collura ◽  
Giuseppina Iacoviello ◽  
Anna Longo ◽  
Luigi Tranchina ◽  
...  

This work describes the preliminary analysis of Fricke gels dosimeters characterized by a new formulation making use of a matrix of polyvinyl alcohol cross-linked by adding glutaraldehyde and analyzed by means of nuclear magnetic resonance relaxometry. In previous optical studies, these gels have shown promising dosimetric features in terms of photon sensitivity and low diffusion of ferric ions produced after irradiation. In this work, we used a portable nuclear magnetic resonance relaxometer to measure the relaxation times (which are important for dosimetric applications) of these gel materials. For this purpose, we performed a study for optimizing the acquisition parameters with a nuclear magnetic resonance relaxometer. Gel samples were exposed to clinical 6 MV photons in the dose range between 0 and 20 Gy. Nuclear magnetic resonance relaxometry measurements were per- formed and the sensitivity to photon beams was measured for various values of the Fe2+ ion concentration. The analyses pointed out that the MR signal increases as the Fe2+ content in- creases and the increase is about 75 % when the concentration of Fe2+ ions is increased from 0.5 mM to 2.5 mM. Furthermore, the sensitivity improvement achieved with increasing the Fe2+ concentration is about 60 %. This paper shows that the portable nuclear magnetic resonance relaxometer used for analysis of porous materials can be used for characterization of these dosimetric gels and this study can be considered as the first step for the characterization of these dosimeters which in future could be used for 3-D dose mapping in clinical applications.


2015 ◽  
Vol 121 ◽  
pp. 14-17 ◽  
Author(s):  
Paulo Falco Cobra ◽  
Bruna Ferreira Gomes ◽  
Cirlei Igreja Nascimento Mitre ◽  
Lucio Leonel Barbosa ◽  
Lucinéia Vizzotto Marconcini ◽  
...  

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