Guidelines for Checking Performance and Verifying Accuracy of Rotational Rheometers: Viscosity Measurements in Steady and Oscillatory Shear

Laun, Martin; Auhl, Dietmar; Brummer, R.; Dijkstra, Dirk J.; Gabriel, Claus; Mangnus, Marc; Rüllmann, Maximilian; Zoetelief, Wim; Handge, Ulrich A.

doi:10.1515/iupac.86.0015

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…Laun et al [1] provided guidelines for checking performance and verifying the accuracy of rotational rheometers. Functional relations of viscosity with torque and angular speed for several types of rotational rheometers are also listed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Systematic Error and Uncertainty of Viscosity Measurements of Mixtures of Monoethanol Amine and Water in Coaxial Cylinder Rheometers

Karunarathne¹

2018

IJMO

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In this study, the use of coaxial cylinder viscometer in viscosity measurements of monoethanol amine and water mixture is discussed. Random and systematic effects engage with the rheometer lead to deviate the measured quantity from its actual value. Compensation for the systematic effect is called as the bias and this compensation can not be done perfectly. The measurement uncertainty arises due to the lack of exact knowledge on what is being measured. Identification of uncertainty sources is vital in uncertainty analysis to evaluate the total uncertainty of a measuring technique. The calculated expanded (k=2) uncertainty of viscosity measurement of an alkanol amine and water mixture using a coaxial cylinder viscometer in this work is 0.0162 mPa• s. Further, the viscosities of mixtures of monoethanol amine and water mixtures under temperature 20-130 o C are measured. This is the normal temperature range for a traditional amine based CO 2 capture process. Viscosity deviations are modeled according to Redlich-Kister type correlation and parameters are found through a regression analysis.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Systematic Error and Uncertainty of Viscosity Measurements of Mixtures of Monoethanol Amine and Water in Coaxial Cylinder Rheometers

Karunarathne¹

2018

IJMO

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“…At very low shear rates, the viscosity tends to a plateau value for some samples, the zero-shear-rate viscosity η 0 . We were not able to measure reliable plateau value at very low shear rates (<< 0.1 s -1 ) for all samples: low viscous gels such as mucilage can be subjected to artefacts at very low shear rates due to non-equilibration (Laun et al, 2014). Other methods such as rotational viscometry with concentric cylinders are better adapted to measure the viscosity of low viscous gels at such shear rates (Mezger, T. G., 2014).…”

Section: Physical Propertiesmentioning

confidence: 89%

Effect of environmental conditions on physical properties of maize root mucilage.

Knott

Ani²,

Kroener³

et al. 2022

Preprint

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High viscosity, low surface tension and hydrophobicity are specific properties of maize root mucilage which contribute to modulate the spatial configuration of the liquid phase in soil pores. Being a hotspot for nutrient absorption, root exudation and microbial activity, the rhizosphere soil solution is suspected to chemically vary strongly upon time. Although the physical properties of maize root mucilage have been repeatedly measured in the last years, their variation upon a changing chemical environment and understanding of the chemical mechanisms governing these properties remain unexplored. Therefore, we investigated how flow and surface properties of maize root mucilage varied by changes in pH, CaCl2 and lecithin concentrations. Results reveal that the physical properties of mucilage can strongly vary depending on the environmental conditions. Low surface tension of maize root mucilage at pH7 was increased by addition of calcium. Upon pH change and lecithin addition, hydrophobic mucilage turned hydrophilic. Viscosity of mucilage decreased with increasing Ca concentration above 2.5 mM, the addition of 0.5 mg/L lecithin and a pH rise to 9. Such variations strongly suggest that the role of mucilage in hydraulic processes in the rhizosphere depends on changes of solutes concentration and composition, which themselves vary according to plant growth and soil water content. It seems that mucilage can best serve as a hydraulic bridge only under certain chemical environments, whose spatio-temporal occurrence in the changing rhizosphere remains to be defined.

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“…At very low shear rates, the viscosity tends to a plateau value for some samples, the zero-shear-rate viscosity η 0 . We were not able to measure reliable plateau value at very low shear rates (< < 0.1 s −1 ) for all samples: low viscous gels such as mucilage can be subjected to artefacts at very low shear rates due to non-equilibration (Laun et al 2014). Other methods such as rotational viscometry with concentric cylinders are better adapted to measure the viscosity of low viscous gels at such shear rates (Mezger 2014).…”

Section: Physical Propertiesmentioning

confidence: 89%

Effect of changing chemical environment on physical properties of maize root mucilage

et al. 2022

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Aims High viscosity, low surface tension and hydrophobicity are specific properties of maize root mucilage which contribute to modulate the spatial configuration of the liquid phase in soil pores. Several processes in the rhizosphere, in particularly nutrient absorption, root exudation and microbial activity, may cause strong temporal variations in the chemistry of the soil solution of the rhizosphere. Although the physical properties of maize root mucilage have been repeatedly measured in the last years, their variation upon a changing chemical environment and understanding of the chemical mechanisms governing these properties remain unexplored. Methods We investigated how flow and surface properties of maize root mucilage varied by changes in pH, calcium chloride (CaCl2) and lecithin concentrations. Results The physical properties of mucilage can strongly vary depending on the environmental conditions. Low surface tension of maize root mucilage at pH7 was increased by addition of calcium. Upon pH change and lecithin addition, hydrophobic mucilage turned hydrophilic. High Ca concentration above 0.83 mmol Ca (g dry mucilage)−1, the addition of 167 μg lecithin (g dry mucilage)−1 and a pH rise to 9 decreased the viscosity of mucilage. Conclusion Such variations strongly suggest that the role of mucilage in hydraulic processes in the rhizosphere depends on changes of solutes concentration and composition, which themselves vary according to plant growth and soil water content. It seems that mucilage can best serve as a hydraulic bridge only under certain chemical environments, whose spatio-temporal occurrence in the changing rhizosphere remains to be defined.

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Guidelines for Checking Performance and Verifying Accuracy of Rotational Rheometers: Viscosity Measurements in Steady and Oscillatory Shear

Cited by 4 publications

References 14 publications

Evaluation of Systematic Error and Uncertainty of Viscosity Measurements of Mixtures of Monoethanol Amine and Water in Coaxial Cylinder Rheometers

Evaluation of Systematic Error and Uncertainty of Viscosity Measurements of Mixtures of Monoethanol Amine and Water in Coaxial Cylinder Rheometers

Effect of environmental conditions on physical properties of maize root mucilage.

Effect of changing chemical environment on physical properties of maize root mucilage

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