Turbulence in surgical suction heads as detected by MRI
Journal of Extra-Corporeal Technology 55(2), 70–81 (2023)
Velocity-compensated T1-weighted 3D MRI was evaluated as a qualitative method for detecting turbulence in four geometrically different cardiotomy suction heads over flow rates up to 1250 mL/min. Modified suction geometries produced substantially less turbulence than the standard control, demonstrating both the importance of suction-head geometry and the potential of MRI for investigating flow-related blood damage.
A New Evaluation Q-Factor to Be Calculated for Suction Geometries as a Basis for Smooth Suction in the Operating Field to Ensure the Highest Possible Blood Integrity for Retransfusion Systems
Journal of Extra-Corporeal Technology 54(2), 107–114 (2022)
Twenty-seven surgical suction tips were investigated with respect to acoustic stress and negative-pressure behaviour, both of which may contribute to mechanical blood damage during surgical suction. A dimensionless Q-factor was introduced to compare suction geometries and assess their overall performance with regard to suction behaviour and preservation of blood integrity.
Bulk viscosity universality and scaling function near the binary liquid consolute point
The Journal of Chemical Physics 131, 174502 (2009)
Hydrodynamic theory and the concept of a frequency-dependent complex specific heat are used to describe the low-frequency bulk viscosity near the consolute point of binary liquids. The treatment connects different descriptions of critical sound attenuation and examines the universal scaling behaviour of the bulk viscosity.
Critical dynamics at the col point of the ternary system methanol–n-hexane–cyclohexane
Journal of Molecular Liquids 145(2), 103–108 (2009)
Ultrasonic spectroscopy, quasielastic light scattering and shear-viscosity measurements were combined to investigate critical dynamics at the col point of the ternary methanol/n-hexane/cyclohexane system. Correlation length, fluctuation relaxation rate and ultrasonic scaling behaviour reveal predominantly quasibinary critical behaviour.
Relaxation rate and scaling function of the critical system 3-methylpentane–nitroethane–cyclohexane
The Journal of Chemical Physics 129, 064516 (2008)
The ternary 3-methylpentane/nitroethane/cyclohexane system was compared with its limiting binary mixtures using shear viscosity, dynamic light scattering and frequency-dependent ultrasonic attenuation. Correlation length, fluctuation relaxation rate and the ultrasonic scaling function show the characteristic critical behaviour expected for quasibinary systems.
Critical Behavior and Crossover Effects in the Properties of Binary and Ternary Mixtures and Verification of the Dynamic Scaling Conception
Dissertation, Georg-August-Universität Göttingen (2007)
Broadband ultrasonic spectroscopy, dynamic light scattering and shear-viscosity measurements are combined to investigate critical dynamics in binary and ternary liquid mixtures. Particular emphasis is placed on dynamic scaling, crossover between different regimes of critical behaviour, and the separation of critical fluctuations from additional molecular relaxation processes.
Dynamic scaling and background relaxation in the ultrasonic spectra of the ethanol–dodecane critical mixture
Chemical Physics Letters 435, 263–267 (2007)
Ultrasonic spectroscopy reveals a low-frequency background relaxation that must be separated from the critical contribution in ethanol/dodecane. After accounting for this additional process, the critical ultrasonic contribution can be compared consistently with dynamic scaling behaviour supported by light-scattering and shear-viscosity data.
Dynamic Scaling and Slowing Down in Chemical Reactions of the Critical Triethylamine–Water System
The Journal of Physical Chemistry B 111, 1438–1442 (2007)
Ultrasonic attenuation measurements were combined with light-scattering and shear-viscosity data to determine the critical scaling behaviour of triethylamine/water. In addition to the critical contribution, non-critical relaxation processes exhibit non-Arrhenius temperature dependence associated with slowing of chemical reactions.
Dynamic scaling of the critical mixture perfluoromethylcyclohexane–carbon tetrachloride
Journal of Physics D: Applied Physics 40, 3248–3253 (2007)
Ultrasonic attenuation, heat-capacity, static and dynamic light-scattering and shear-viscosity data were jointly re-evaluated using dynamic scaling theory. The critical ultrasonic contribution is separated from an additional non-critical relaxation process associated with molecular conformational dynamics.
Dynamic scaling of the critical binary mixture methanol–hexane
The Journal of Chemical Physics 124, 144505 (2006)
Acoustic attenuation spectroscopy, dynamic light scattering, shear viscosity, density and heat-capacity measurements were combined for critical methanol/n-hexane. Independently determined fluctuation relaxation rates are compared, while the critical acoustic contribution is examined within the framework of dynamic scaling theory.
Critical Dynamics of the Binary System Nitroethane/3-Methylpentane: Relaxation Rate and Scaling Function
The Journal of Physical Chemistry A 110, 4313–4319 (2006)
Complementary ultrasonic, light-scattering and transport measurements are used to characterize the relaxation of concentration fluctuations in the critical nitroethane/3-methylpentane mixture. The resulting relaxation rates and acoustic response provide an experimental test of dynamic scaling close to the consolute point.
Relaxation rate in the critical dynamics of the micellar i-C4E1/H2O system with lower consolute point
Physical Review E 73, 061508 (2006)
Critical dynamics in the micellar isobutoxyethanol/water system are studied by combining acoustic and complementary transport measurements. The acoustic data are examined within dynamic scaling theory, while deviations in the temperature dependence indicate the presence of an additional weak low-frequency relaxation process.
Critical dynamics and kinetics of elementary reactions of 2,6-dimethylpyridine–water
Chemical Physics Letters 431, 308–312 (2006)
Broadband ultrasonic spectra are considered together with relaxation rates obtained from dynamic light scattering and shear-viscosity measurements for critical 2,6-dimethylpyridine/water. The measurements allow the critical dynamics to be separated from possible contributions of elementary chemical equilibria.
Critical dynamics of binary liquids. Recent evidence from dynamic light scattering and shear viscosity measurements as well as broadband ultrasonic spectrometry
Uzbek Journal of Physics 8, 223–238 (2006)
Ultrasonic attenuation spectroscopy, quasielastic light scattering and shear-viscosity measurements are reviewed for liquid systems exhibiting critical fluctuations. Binary mixtures are considered alongside more complex systems in order to examine dynamic scaling and the interplay between critical fluctuations and additional molecular relaxation phenomena.
Concentration Fluctuations and Crossover Effects of Critical Binary Liquids Near Their Consolute Point
51st Open Seminar on Acoustics, Gdańsk (2004)
The contribution addresses concentration fluctuations in binary liquids approaching their consolute point, with particular emphasis on crossover between different regimes of critical behaviour. Experimentally accessible relaxation dynamics are placed in the broader framework of critical scaling and crossover phenomena.
Sound attenuation, shear viscosity, and mutual diffusivity behavior in the nitroethane–cyclohexane critical mixture
The Journal of Chemical Physics 121, 5929–5934 (2004)
Ultrasonic attenuation, shear viscosity and mutual diffusivity are investigated jointly in the critical nitroethane/cyclohexane mixture. Separation of the non-critical acoustic background allows the critical contribution to be examined in relation to the relaxation of concentration fluctuations and dynamic scaling behaviour.
Critical fluctuations near the consolute point of n-pentanol–nitromethane. An ultrasonic spectrometry, dynamic light scattering, and shear viscosity study
The Journal of Chemical Physics 120, 9192–9198 (2004)
Ultrasonic attenuation spectroscopy, dynamic light scattering and shear-viscosity measurements are combined to investigate critical fluctuations in n-pentanol/nitromethane near its consolute point. After separating the non-critical acoustic background, the critical contribution is examined using the scaling behaviour of concentration fluctuations.
Verifizierung der dynamischen Skalierungshypothese mittels Ultraschallspektroskopie und quasielastischer Lichtstreuung / Das binäre kritische System Nitromethan/Pentanol
Diplomarbeit, Georg-August-Universität Göttingen (2003)
Ultrasonic spectroscopy and quasielastic light scattering are combined to investigate concentration fluctuations and critical slowing down in the binary nitromethane/pentanol system near its consolute point. The work examines the dynamic scaling hypothesis by comparing relaxation behaviour obtained from complementary acoustic and optical measurements.