Monitoring of engine oil aging by diffusion and low-field nuclear magnetic resonance relaxation

Time domain, also named lowfield nuclear magnetic resonance is used to monitor oil degradation by measuring relaxation and diffusion. As quality control of oils is indispensable to optimize oil change intervals while simultaneously preventing machinery damage, the technique was applied to detect the degradation state of engine oils as time domain nuclear magnetic resonance is known as a well suited tool to measure quality control parameters for example in food industry. Correlations with commonly applied oil analytics like viscosity measurements and inductively coupled plasma optical emission spectrometry allow to interpret relaxation and diffusion data in detail and finally to deepen the understanding of oil aging processes. Additionally, the measurement temperature was varied to achieve the maximum sensitivity towards oil aging. Low field NMR is not only realized in form of table top instruments, but also in form of field cycling and single sided NMR devices. Fast field cycling as well as single-sided NMR were also explored to study oil aging and to provide valuable insight. The latter device was used to obtain information about translational diffusion and transverse relaxation of oils simultaneously.Fil: Förster, Eva. Karlsruher Institut für Technologie; AlemaniaFil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Küstner, Jan. Karlsruher Institut für Technologie; AlemaniaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; ArgentinaFil: Nirschl, Hermann. Karlsruher Institut für Technologie; AlemaniaFil: Guthausen, Gisela. Karlsruher Institut für Technologie; Alemani

The "corset effect" of spin-lattice relaxation in polymer melts confined in nanoporous media

Linear polyethylene oxides with molecular weights Mw of 1665 and 10170 confined in pores with variable diameters in a solid methacrylate matrix were studied by proton field-cycling nuclear magnetic resonance relaxometry. The pore diameter was varied in the range of 9-57 nm. In all cases, the spin-lattice relaxation time shows a frequency dependence close to T1 ∝ ν3/4 in the range of ν = 3·10 -1-2·101 MHz as predicted by the tube-reptation model. This proton T1 dispersion essentially reproduces that found in a previous deuteron study (R. Kimmich, R.-O. Seitter, U. Beginn, M. Möller, N. Fatkullin: Chem. Phys. Lett. 307, 147, 1999). As a feature particularly characteristic for reptation, this finding suggests that reptation is the dominating chain dynamics mechanism under pore confinement in the corresponding time range. The absolute values of the spin-lattice relaxation times indicate that the diameter of the effective tubes in which reptation occurs is much smaller than the pore diameters on the time scale of spin-lattice relaxation experiments. An estimation leads to a value d* ∼ 0.5 nm. The impenetrability of the solid pore walls, the uncrossability of polymer chains (·excluded volume·) and the low value of the compressibility in polymer melts create the ·corset effect· which reduces the lateral motions of polymer chains to a microscopic scale of only a few tenths of a nanometer

Biochar successfully replaces activated charcoal for in vitro culture of two white poplar clones reducing ethylene concentration

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Use of 1H-NMR spectroscopy, diffusometry and relaxometry for the characterization of thermally-induced degradation of motor oils

We explore the capability of 1H NMR spectroscopy, relaxation and diffusion for the characterization of thermally-induced degradation of fresh motor oils. Temperature dependent measurements of diffusion show a weak sensitivity to thermal degradation. In contrast, both the transverse relaxation at 1H Larmor frequencies of 20 MHz and 400 MHz, as well as the longitudinal relaxation at 60 kHz showed to be sensitive to thermally-induced effects at measured temperatures within the range −10 °C to 30 °C. Results show that the highest sensitivity significance can be reached by fast field-cycling NMR relaxometry measurements at low magnetic fields.Fil: Fraenza, Carla Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Förster, E.. Karlsruher Institut fur Technologie; AlemaniaFil: Guthausen, Gisela. Karlsruher Institut fur Technologie; AlemaniaFil: Nirschl, Hermann. Karlsruher Institut fur Technologie; AlemaniaFil: Anoardo, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

The "corset effect" of spin-lattice relaxation in polymer melts confined in nanoporous media

Linear polyethylene oxides with molecular weights Mw of 1665 and 10170 confined in pores with variable diameters in a solid methacrylate matrix were studied by proton field-cycling nuclear magnetic resonance relaxometry. The pore diameter was varied in the range of 9-57 nm. In all cases, the spin-lattice relaxation time shows a frequency dependence close to T1 ∝ ν3/4 in the range of ν = 3·10 -1-2·101 MHz as predicted by the tube-reptation model. This proton T1 dispersion essentially reproduces that found in a previous deuteron study (R. Kimmich, R.-O. Seitter, U. Beginn, M. Möller, N. Fatkullin: Chem. Phys. Lett. 307, 147, 1999). As a feature particularly characteristic for reptation, this finding suggests that reptation is the dominating chain dynamics mechanism under pore confinement in the corresponding time range. The absolute values of the spin-lattice relaxation times indicate that the diameter of the effective tubes in which reptation occurs is much smaller than the pore diameters on the time scale of spin-lattice relaxation experiments. An estimation leads to a value d* ∼ 0.5 nm. The impenetrability of the solid pore walls, the uncrossability of polymer chains (·excluded volume·) and the low value of the compressibility in polymer melts create the ·corset effect· which reduces the lateral motions of polymer chains to a microscopic scale of only a few tenths of a nanometer

Western Star, 1908-11-18

The Western Star began publication on Newfoundland's west coast on 4 April 1900, appearing weekly with brief semiweekly periods up to 1952, when it became a daily. As of 17 April 2019 it continues as a free weekly community paper

The "corset effect" of spin-lattice relaxation in polymer melts confined in nanoporous media

Linear polyethylene oxides with molecular weights Mw of 1665 and 10170 confined in pores with variable diameters in a solid methacrylate matrix were studied by proton field-cycling nuclear magnetic resonance relaxometry. The pore diameter was varied in the range of 9-57 nm. In all cases, the spin-lattice relaxation time shows a frequency dependence close to T1 ∝ ν3/4 in the range of ν = 3·10 -1-2·101 MHz as predicted by the tube-reptation model. This proton T1 dispersion essentially reproduces that found in a previous deuteron study (R. Kimmich, R.-O. Seitter, U. Beginn, M. Möller, N. Fatkullin: Chem. Phys. Lett. 307, 147, 1999). As a feature particularly characteristic for reptation, this finding suggests that reptation is the dominating chain dynamics mechanism under pore confinement in the corresponding time range. The absolute values of the spin-lattice relaxation times indicate that the diameter of the effective tubes in which reptation occurs is much smaller than the pore diameters on the time scale of spin-lattice relaxation experiments. An estimation leads to a value d* ∼ 0.5 nm. The impenetrability of the solid pore walls, the uncrossability of polymer chains (·excluded volume·) and the low value of the compressibility in polymer melts create the ·corset effect· which reduces the lateral motions of polymer chains to a microscopic scale of only a few tenths of a nanometer

The "corset effect" of spin-lattice relaxation in polymer melts confined in nanoporous media

Linear polyethylene oxides with molecular weights Mw of 1665 and 10170 confined in pores with variable diameters in a solid methacrylate matrix were studied by proton field-cycling nuclear magnetic resonance relaxometry. The pore diameter was varied in the range of 9-57 nm. In all cases, the spin-lattice relaxation time shows a frequency dependence close to T1 ∝ ν3/4 in the range of ν = 3·10 -1-2·101 MHz as predicted by the tube-reptation model. This proton T1 dispersion essentially reproduces that found in a previous deuteron study (R. Kimmich, R.-O. Seitter, U. Beginn, M. Möller, N. Fatkullin: Chem. Phys. Lett. 307, 147, 1999). As a feature particularly characteristic for reptation, this finding suggests that reptation is the dominating chain dynamics mechanism under pore confinement in the corresponding time range. The absolute values of the spin-lattice relaxation times indicate that the diameter of the effective tubes in which reptation occurs is much smaller than the pore diameters on the time scale of spin-lattice relaxation experiments. An estimation leads to a value d* ∼ 0.5 nm. The impenetrability of the solid pore walls, the uncrossability of polymer chains (·excluded volume·) and the low value of the compressibility in polymer melts create the ·corset effect· which reduces the lateral motions of polymer chains to a microscopic scale of only a few tenths of a nanometer