-
Lehrum, Hans Vigeland; Andersen, Niels Højmark; Eriksen, Dag Øistein; Hansen, Eddy Walther & Omtvedt, Jon Petter
(2020).
NMR Studies of Aliquat 336 in toluene after contact with saline solutions - Determination of ionic content.
-
Alireza, Hassani; Hansen, Eddy Walther; Olsbye, Unni & Fredriksen, Siw Bodil
(2020).
Segmental Orientation and Mobility of Ultra-high Molecular Weight Polyethylene
.
Vis sammendrag
Abstract:
Formation of entanglements in Ultra-High Molecular Weight Polyethylene (UHMWPE with average molecular weight exceeding 10^6 g.mol-1 limits their processability [1]. Entanglement characterization techniques mostly requires processing of nascent reactor powder, by melting. This will, however disturb the initial properties, and accordingly, the initial entanglement density in polymers. Therefore, Nuclear Magnetic Resonance (NMR) is an interesting alternative technique where the properties of UHMWPE can be explored in the solid state. However, during relevant NMR studies, the samples were either melted or exposed to time-intensive 13C high field NMR experiments [2]. Recently, simple low field, time-domain NMR with no need for isotope labeling, is gaining attention [3].
The aim of this study is to detect local mobility and orientation of chains across UHMWPE semi-crystalline network, in the solid state. The transverse relaxation time (T2) is determined from the Free Induction Decay (FID) of samples synthesized during controlled catalytic Polymerisation. The method is used to detect differences in dynamic behaviour of UHMWPE samples by mapping the crystalline/amorphous topology [3]. However, due to inhomogeneity in the magnetic field, obtaining detailed information about local chain diffusion is difficult with said experiment. Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence is designed to overcome this issue by refocusing the dephased magnetization in the transverse plane [4]. Thus, CPMG will be used for accurate measurement of the T2 distribution in UHMWPE samples at temperatures between 40-120 °C (below melting temperature).
References:
[1] A. Pawlak, "The Entanglements of Macromolecules and Their Influence on the Properties of Polymers," Macromolecular Chemistry and Physics, vol. 220, no. 10, p. 1900043, 2019.
[2] Y. Yao, S. Jiang, and S. Rastogi, "13C Solid State NMR Characterization of Structure and Orientation Development in the Narrow and Broad Molar Mass Disentangled UHMWPE," Macromolecules, vol. 47, no. 4, pp. 1371-1382, 2014.
[3] R. Bärenwald et al., "Local flips and chain motion in polyethylene crystallites: a comparison of melt-crystallized samples, reactor powders, and nanocrystals," Macromolecules, vol. 47, no. 15, pp. 5163-5173, 2014.
[4] A. K. Whittaker, T. Bremner, and F. O. Zelaya, "The effect of field inhomogeneities and molecular diffusion on the NMR transverse relaxation behaviour of polymer melts," Polymer, vol. 36, no. 11, pp. 2159-2164, 1995.
-
Hansen, Eddy Walther & Yao, Ye-Feng
(2020).
INTERFACIAL WATER IN MESOPORES BELOW FREEZING
.
-
Lerum, Hans V.; Sand, Svetlana; Eriksen, Dag Øistein; Hansen, Eddy Walther; Wibetoe, Grethe & Omtvedt, Jon Petter
(2018).
Determination of Distribution Ratios in Liquid-liquid
Extraction of Hydrometallurgical Process Solutions using ICP-MS and
Radiotracer Techniques.
-
mosquera-vitas, carme; Hansen, Eddy Walther; Garcia-Santos, Hlenda; Nelson, Obregon-Neira; Celis Ossa, Raul Ernesto & Alberto Gonzalez-Murillo, Carlos
[Vis alle 7 forfattere av denne artikkelen]
(2017).
Leaching potential of chlopyrifos in an Andisol and Entisol: adsorption-desorption and degradation studies.
Geophysical Research Abstracts.
ISSN 1029-7006.
19.
Vis sammendrag
Ecological status of tropical soils like high OC content and microbial activity plays a key role to reduce the leaching
of insecticide chlorpyrifos through the soil profile and therefore into groundwater. We found that chlorpyrifos has
“transitional” leaching potential (GUS values varied between 1.8 and 2.5) throughout the soil depth, which differs
from the “nonleacher” classification for temperate soils as based on surface level t1/2 and Koc values from international
databases. These findings provide strong evidence of the importance of estimating the transport parameters
and insecticide concentrations in different soil layers, especially when the amount and type of OC content vary
throughout the soil profile. We got to such conclusions after studying the soil profile structural composition of soil
organic matter and the adsorption/desorption characteristics of the insecticide in two different soil profiles (Andisol
and Entisol) under agriculture production using Fourier transform infrared spectroscopy, nuclear magnetic
resonance, and batch analysis methods.
-
Lerum, Hans Vigeland; Bouzga, Aud Mjærum; Jørgensen, Sissel; Petersen, Dirk; Eriksen, Dag Øistein & Hansen, Eddy Walther
[Vis alle 8 forfattere av denne artikkelen]
(2016).
Study of cadmium extraction from aqueous solutions with high chloride concentration using radiotracer and NMR
.
-
Lerum, Hans Vigeland; Bouzga, Aud Mjærum; Jørgensen, Sissel; Petersen, Dirk; Eriksen, Dag Øistein & Hansen, Eddy Walther
[Vis alle 8 forfattere av denne artikkelen]
(2016).
LIQUID-LIQUID EXTRACTION OF CADMIUM CHLORIDE COMPLEXES STUDIED BY NMR.
-
Rørvik, Per Martin; Arstad, Bjørnar; Jørgensen, Sissel; Stub, Sindre Østby; Norby, Truls & Hansen, Eddy Walther
(2016).
1H-NMR and Resistance Study of Surface-Adsorbed Water in Porous YSZ.
-
Hansen, Eddy Walther & Zhu, Han
(2016).
A continuous- and a discrete spin-spin relaxation rate representation of water in meat – A comparative investigation.
.
-
Hansen, Eddy Walther & Han, Zhu
(2014).
SPATIAL REDISTRIBUTION OF WATER IN MEAT DURING DRIP LOSS AS PROBED BY LOW FIELD 1H-NMR.
-
Jobby, Paul; Hansen, Eddy Walther; Bouzga, Aud; Jørgensen, Sissel & Arstad, Bjørnar
(2013).
SIGNS OF SPATIAL HETEROGENEITIES WITHIN XLPE CABLE INSULATION PROBED BY SOLID STATE 1H-NMR.
-
Hansen, Eddy Walther
(2013).
Diffusion of Pore Confined Fluid Exemplified by Benzene in MOF.
-
Hansen, Eddy Walther
(2013).
Application of Solid State NMR Spectroscopy in Polymer Science.
-
Paul, Jobby; Hansen, Eddy Walther; Roots, Jaan & Jørgensen, Sissel
(2012).
Thermal Oxidation of XLPE monitored by solid state 1H-NMR.
-
Hansen, Eddy Walther
(2012).
Application of NMR in Physical Chemistry - A Retrospective view.
-
Braovac, Susan; Kutzke, Hartmut; Jørgensen, Sissel; Bouzga, Aud Mjærum; Hansen, Eddy Walther & Arstad, Bjørnar
(2012).
ALUM-TREATED WOOD: CHARACTERIZATION USING INFRARED SPECTROSCOPY AND SOLID STATE NMR.
-
Hansen, Eddy Walther; Paul, Jobby; Roots, Jaan; Jørgensen, Sissel; Poltimae, T & Krumme, Andres
(2012).
Easy access to the amount of short chains in ethene/alfa-alkene copolymers from solid state 1H-MAS NMR.
Vis sammendrag
Abstract
Solid state 1H-MAS NMR is shown to be an attractive experimental technique for determining the comonomer content in ethene-alfa-alkene copolymers. Its advantage is associated with: a) no particular need for sample preparation, b) non-destructive, c) short overall acquisition time of the order of a few minutes. d) no need for calibration and finally e) the copolymer content in cross-linked LDPE may be determined, which is otherwise not easily accessible, as these samples are non-soluble in most liquids.
References
E. W. Hansen, J. Paul, S. Jørgensen, B. Arstad and A. Bouzga, IJRRAS, 2011, 6, 382–390.
-
barreto, carlos; Hansen, Eddy Walther & Fredriksen, Siw
(2012).
Novl organic solvent-free purification of poly(propylene carbonate): tailoring the composition and thermal properties.
-
Braovac, Susan; Kutzke, Hartmut; Jørgensen, Sissel; Bouzga, Aud Mjærum; Arstad, Bjørnar & Hansen, Eddy Walther
(2011).
Alum-treated wood: characterization using infrared spectroscopy and solid state 1h and 13C NMR.
Vis sammendrag
Abstract
The Oseberg find contains a large proportion of hardwoods that had been treated about 100 years ago with hot solutions of alum salts (potassium aluminum sulfate dodecahydrate, KAl(SO4)2 . 12H2O). Today, the wood is characterized by a high acidity (pH 1) and is structurally highly degraded. The observed deterioration is also active. The ‘alum treatment’ was a method of choice for the conservation of highly deteriorated waterlogged archaeological wood found from 1850 – 1950 and has since been replaced by treatment with polyethylene glycols (PEG). The alum treatment has been mainly used in Scandinavia but also in the USA, Japan and other European countries.
Attempts to chemically characterize the alum-treated wood from the Oseberg find is one phase in the research currently being undertaken at the Museum of Cultural History as a part of the Alum Research Project. The ultimate aim of this project is to design conservation re-treatments which will stabilize and strengthen the wood. So far, we have focussed on non-destructive analytical techniques using ATR-FTIR and solid state NMR. Further chemical analyses are planned, using destructive techniques.
Analyses using infrared spectroscopy and solid state 1H and 13C NMR were undertaken on selected alum-treated samples and compared with fresh woods as well as archaeological woods from the same find not treated with alum. The advantages of these analytical techniques lie in the fact that sample preparation is minimal prior to measurement – highly deteriorated wood can be greatly modified by standard sample preparation procedures. These techniques, when used together, give an acceptable level of qualitative structural information regarding the state of the remaining polymers.
Analytical results demonstrated that all alum-treated samples are highly degraded relative to archaeological wood from the same find not treated with alum salts. The non-alum-treated archaeological wood has carbohydrates left, which are highly reduced in the alum-treated wood. 13C NMR can distinguish different lignin types, and has shown that syringyl lignin is more deteriorated than guaiacyl lignin in the most deteriorated alum-treated samples. NMR and FTIR-ATR results also show that remaining polymers in the alum-treated wood, dominated by lignins, are highly oxidized and contain carboxylic groups. This shows that the alum-treatment has caused extensive chemical changes in the wood, resulting in wood with a powdery consistency with almost no structural integrity relative to samples from Oseberg not treated with alum.
-
Hansen, Eddy Walther; Gong, Xiaoliang; Chen, Qun & Zhenshu, Zhu
(2011).
The Distribution Properties of the Diffusivity Derived from PFG NMR Characterized by a Stretched-Exponential Response Function.
-
Hansen, Eddy Walther
(2010).
Chain Diffusion in Semi-Crystalline Polymers.
-
Hansen, Eddy Walther
(2009).
Morphology and Chain Dynamics in PE (Spin-Diffusion and Carbon T1-relaxation).
-
Hansen, Eddy Walther
(2009).
Solid State NMR - an Experimental Challenge (Principles and Applications).
-
Hansen, Eddy Walther
(2008).
Solid State NMR - An Overview.
Vis sammendrag
Prinsippene for fastfase NMR belyst med eksempler hentet fra materialkjemien/materialfysikken
-
Hansen, Eddy Walther
(2008).
Spin Diffusion - Principles and Application.
-
Ukkelberg, Åsmund; Hansen, Eddy Walther; Sørland, Geir Humborstad & Widerøe, Hege C.
(2008).
ANAHESS, a New Second Order Inverse Laplace Transform Algorithm.
-
Qun, Chen; Zhang, Lili; Shu, Jie; Hansen, Eddy Walther & Zhang, Shanmin
(2007).
Quantitative CP/MAS NMR methods for studying polymer structures.
-
Hansen, Eddy Walther; Ukkelberg, Åsmund; Sørland, Heir Humborstad & Widerøed, Hege C.
(2007).
ANAHESS, a new second order inverse Laplacetransform algorithm using analytic expressions for thegradient and the Hessian matrix, with NMR applications.
-
Hansen, Eddy Walther & Gran, Hans Christian
(2006).
Combined NMR Relaxation and Cryogenic NMR to Probe Pore-Architecture (Water Confined in Porous Polymer Particles).
-
Hansen, Eddy Walther; Bakken, Egil & Gran, Hans Christian
(2006).
Sorption energetics and diffusion of methyl salicylate in chloro-butyl rubber.
-
Hansen, Eddy Walther & Gran, Hans Christian
(2005).
Probing Pore-Structure within Porous Polymer Particles by NMR.
Diffusion Fundamentals.
ISSN 1862-4138.
3,
s. 21.1–21.2.
Vis sammendrag
How to probe pore morphology or pore-structure by combining NMR Cryoporometry and NMR relaxometry
-
Hansen, Eddy Walther; Kortunov, P; Vasenkov, S; Kaerger, J; Fe Elia, M & Perez, M
[Vis alle 17 forfattere av denne artikkelen]
(2005).
Investigation of Molecular Diffusion in FCC Catalysts.
Diffusion Fundamentals.
ISSN 1862-4138.
s. 458–459.
-
Hansen, Eddy Walther & Pedersen, Bjørn
(2003).
Årets Nobelpris i fysiologi eller medisin: Heder til NMR-spektroskopikere.
Kjemi.
ISSN 0023-1983.
s. 14–16.
-
Hansen, Eddy Walther
(2003).
Why bother with low-field/low-resolution NMR ?
-
Hansen, Eddy Walther; Kjekshus, Arne & Odden, Jan Ove
(2003).
Local Arrangement of Hydrogen in Amorphous Silicon.
-
Hansen, Eddy Walther
(2002).
Kjernemagnetisme - hvordan utnytte den ?
Vis sammendrag
Prinsippene for MRI og MRS presenteres og belyses med eksempler hentet bla.a fra egen forskningsaktivitet
-
Hansen, Eddy Walther
(2002).
"NMR diffusion and relaxation measurements of organic molecules adsorbed in porous media" av Lars Gjerdåker.
[Radio].
Universitetet i Bergen : Eddy W. Hansen er oppnevnt som opponent til Lars Gjerdåker's dr.scient. avhandling.
-
Hansen, Eddy Walther
(2002).
Probing Pore Size Distribution by Cryogenic NMR.
-
Hansen, Eddy Walther; Simon, Christian; Bredesen, Rune; Raeder, H & Haugsrud, R
(2002).
NMRT, a New Method for Direct Determination of Pore Size Distribution in Porous Membranes.
-
Hansen, Eddy Walther
(2001).
Anmeldelse av boka "Advances in Magnetic Resonance in Food Science".
Kjemi.
ISSN 0023-1983.
s. 25–25.
Vis sammendrag
Anmeldelse av boka "Advances in Magnetic Resonance in Food Science" av R.S.Belton, B.P.Hills and G.A.Webb (eds.), MPG Books Ltd., Bodmin, Cornwall, UK 1999, 293 sider, ISBN 0-85404-724-7
-
Hansen, Eddy Walther & Blom, Richard
(2001).
Rate of Diffusion of Methylaluminoxane and Toluene Through Porous Silica.
Vis sammendrag
Metylaluminoxane (MAO) has a unique position as co-catalysts for metallocene and post-metallocene catalysts1. When heterogenising MAO/toluene on porous supports2, MAO will be distributed throughout the porous particle. How well, it will be distributed will depend on the reactivity of the surface and on the diffusion rate of MAO within the porous system. Moreover, the diffusivity may constitute the rate-limiting step of chemical reactions, and thus dictate the catalytic activity and selectivity3-5.
In this work we present a simple 1H-NMR experimental approach, which enables the diffusivity within a porous material to be determined.
An NMR tube was filled with deuterated toluene, and separated in two sections by a porous, cylindrical silica membrane (3 mm of length). Small amounts of non-deuterated toluene and MAO were added to one side of the membrane. The diffusion of the species through the membrane was monitored by 1H-NMR.
In order to derive the diffusion coefficients, Fick's equation was solved under certain constraints and initial conditions, and the subsequent mathematical expression fitted to the observed intensity Vs time data. The analysis revealed that the diffusion coefficients of MAO and toluene within the silica membrane were slower - by a factor of 13 and 4 - compared to their bulk diffusion coefficients. Both the experimental approach and the data analysis are discussed thoroughly in the text.
-
Bjørndal, Alexander Raphael Holen; Roots, Jaan & Hansen, Eddy Walther
(2014).
Optical Biosensors for Glucose.
Universitetet i Oslo.
Vis sammendrag
GOx was, to the authors knowledge, for the first time successfully immobilized in DGS. The intrinsic fluorescence of GOx was measured in both solution and a sol-gel derived matrix in both the presence and absence of glucose. A setup to measure the fluorescence intensity in a plate array was developed.
GOx was, to the authors knowledge, for the first time successfully immobilized in DGS. The intrinsic fluorescence of GOx was measured in both solution and a sol-gel derived matrix in both the presence and absence of glucose. A setup to measure the fluorescence intensity in a plate array was developed.
-
Bendiksen, Bård Andre; Hansen, Eddy Walther & Walderhaug, Harald
(2014).
Benzenmobilitet i MOF UiO-67 karakterisert med proton lavfelt NMR-målinger -Eksperimenter og simuleringer.
Universitetet i Oslo.
Vis sammendrag
Dette arbeidet utgjør en preliminær undersøkelse av muligheten for å stu- dere sorbentmobilitet i krystallitter av det metall-organiske rammeverket UiO-67, ved å måle selvdiffusjon med et lavfelt NMR-instrument (0,5 T). UiO-67 materialet har blitt syntetisert, preparert og karakterisert for selvdif- fusjonsmålinger. Tolkningen av selvdiffusjonsmålingene har blitt kombinert med simuleringer av både sorpsjon og dynamikk. Studiet viser at det er mulig å bestemme tidsavhengigheten til utvekslingen av benzen mellom porene i krystallittene, og gassfasen mellom krystallittene. Det blir også vist at det er mulig å bestemme selvdiffusjonen til benzen inne i krystallittene som funk- sjon av temperatur. Diffusjonskoeffisientene som bestemmes er lavere enn for bulk benzen, og viser en tidsavhengighet som skyldes begrensningene porene legger på mobiliteten til benzenmolekylene inne i krystallittene. Tidsavhen- gigheten til diffusjonskoeffisienten blir brukt til å bestemme den gjennom- snittlige krystallittradien. Krystallittradien bestemt fra tidsavhengigheten i diffusjonskoeffisienten er i god overenstemmelse med den gjennomsnittlige krystallittradien som bestemmes med mikroskopi.
-
Blokkdal, Espen Hagen & Hansen, Eddy Walther
(2014).
The Self-Diffusion Coefficient of Bulk Fluid Molecules Probed by Transverse Relaxation Measurements in an Inhomogeneous Magnetic Field.
Universitetet i Oslo.
Vis sammendrag
The possibility for performing self-diffusion measurements by Carr-Purcell-Meiboom-Gill (CPMG) experiments using the inherent magnetic field inhomogeneities as a gradient field were tested for six sample molecules, using a Maran Ultra NMR instrument with a 0.5 T permanent magnet. The method tested assumed that the magnetic field inhomogeneities could be approximated by a linear gradient, and the estimated parameter representing the magnetic field inhomogeneities in this model have been estimated to 25 μT2 m−2. The estimated diffusion coefficients were within 10-20 % of literature values, except for some samples, where convection was a problem The estimated field gradient have also been estimated from a Hahn echo experiment, and found to be consistent with the estimate from CPMG. The data obtained have also been used to probe the form of the magnetic field inhomogeneities, and have been found to be well described by a parabolic approximation. Some generalizations of the CPMG-signal was done to account for the parabolic form, which allows the CPMG-signal to be modified by introducing a correction function K, revealing the dependency of the sample height L, vertical displacement of the sample, l, and the form of the NMR tube used.
Sensitivity analysis for the diffusion coefficient have been included, indicating that the diffusion coefficient may be detected as low as 10−11 m2 s−1 at the instrument used. The sensitivity of the K-function for the various parameters have also been included, revealing the sample height as the most influential parameter.
The suitability for the free induction decay (FID) as an experiment for determining the transverse relaxation time have also been tested, and have been indicated to be unsuited for instruments with magnetic field inhomogeneities.
-
-
-
-
Hansen, Eddy Walther & Blom, Richard
(2001).
heterogenization technology.
Sintef.