scholarly journals Rheological evaluation of Prunus mume pulp

2013 ◽  
Vol 16 (4) ◽  
pp. 285-291
Author(s):  
Ernesto Quast ◽  
Lucas Mezzomo ◽  
Leda Battestin Quast ◽  
Flávio Luis Schmidt
Keyword(s):  
Activation Energy ◽  
Power Law ◽  
Rheological Behaviour ◽  
Consistency Index ◽  
Rheological Parameters ◽  
Prunus Mume ◽  
Rotational Viscometer ◽  
Rheological Models ◽  
Rheological Data

The rheological behaviour of mume pulp at 6, 7, 8 and 9 °Brix was investigated using a rotational viscometer at temperatures ranging from 15 to 75 °C. The rheological models of Herschel-Bulkley and Ostwald-Waele (Power Law) were fitted to obtain the rheological parameters of the mume pulp. The product was described as time non-dependent and presented a viscosity of 1.9 Pa.s at 15 °C and 1.1°Pa.s at 65 and 75 °C for the 9 °Brix pulp. The pulp showed non-Newtonian behaviour and the Herschel-Bulkley model was used to describe this behaviour. The activation energy ranged from 6.6-10.6 kJ.mol-1 and the consistency index from 18.0-22.9 Pa.s n for the 9 °Brix pulp and 8.3-12.2 Pa.s n for the 8 °Brix pulp at temperatures varying from 15 to 75 °C. The models presented high correlation values for all the rheological data obtained in the present work.

scholarly journals Determination of Rheological Parameters from Measurements on a Viscometer with Coaxial Cylinders – Choice of the Reference Radius

10.14311/892 ◽  
2006 ◽  
Vol 46 (6) ◽  
Author(s):  
F. Rieger
Keyword(s):  
Experimental Data ◽  
Power Law ◽  
Rheological Behavior ◽  
Experimental Results ◽  
Rheological Parameters ◽  
Concentrated Suspensions ◽  
Rotational Viscometer ◽  
Coaxial Cylinders

Knowledge about rheological behavior is necessary in engineering calculations for equipment used for processing concentrated suspensions and polymers. Power-law and Bingham models are often used for evaluating the experimental data. This paper proposes the reference radius to which experimental results obtained by measurements on a rotational viscometer with coaxial cylinders should be related. 

Rheological Characterisation of Heavy Oil and Impact on its Production Enhancement

2011 ◽  
Vol 367 ◽  
pp. 393-401 ◽  
Author(s):  
Amol Bali ◽  
Babs Mufutau Oyeneyin ◽  
Ebenezer Adom
Keyword(s):  
Power Law ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Horizontal Well ◽  
Rheological Behaviour ◽  
Pvt Properties ◽  
Rheological Models ◽  
Bingham Plastic ◽  
Shear Rates ◽  
Different Temperatures

Criticality of rheology for heavy oil recovery is the main purpose of this paper supported by different results. The Bingham Plastic, Power Law and Herschel Bulkley rheological models have been adopted for the purpose of this paper. Rheological characterisation was carried out for different temperatures. Rheological behaviour of non-Newtonian heavy oil for different shear rates is analysed in this paper. Effective shear and bulk viscosities for different flow rates are compared for all rheological models. Using the horizontal well productivity model, the drawdown values for all rheological models are determined. Similarly for the sand management purpose the critical rates of Newtonian and these three non-Newtonian fluids are plotted to determine the critical drawdown values for each type of fluid. Impact of drainage profile on the effective viscosities is also compared for different drainage profiles. Shear rate models are proposed in this paper for Bingham Plastic, Power Law and Herschel Bulkley rheological models. The new Micro-PVT equipment is also introduced for determining the PVT properties and rheological behaviour of heavy oil. Nomenclature

scholarly journals Dissipative Heating in a Rotational Viscometer with Coaxial Cylinders

10.14311/1053 ◽  
2008 ◽  
Vol 48 (5) ◽  
Author(s):  
F. Rieger
Keyword(s):  
Temperature Distribution ◽  
Heat Resistance ◽  
Power Law ◽  
Outer Cylinder ◽  
Rheological Behaviour ◽  
Dissipative Heating ◽  
Diameter Ratio ◽  
Rotational Viscometer ◽  
Coaxial Cylinders ◽  
Temperature Time

Rotational viscometers with coaxial cylinders are often used for measuring rheological behaviour. If the inner to outer cylinder diameter ratio does not differ significantly from 1, the curvature can be neglected and the flow reduces to the flow between moving and stationary plates. The power-law and Bingham models are often used for describing rheological behaviour. This paper deals with the temperature distribution obtained by solving the Fourier-Kirchhoff equation and in the case of  negligible inner  heat resistance it also covers temperature time dependence. The solution is illustrated by a numerical example. 

Modelling of Rheological Behaviour of Pulps and Purées from Fresh and Frozen-Thawed Murta (Ugni molinae Turcz) Berries

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Kong S. Ah-Hen ◽  
Antonio Vega-Gálvez ◽  
Nelson O. Moraga ◽  
Roberto Lemus-Mondaca
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Rapid Change ◽  
Correlation Coefficients ◽  
Rheological Behaviour ◽  
Type Equation ◽  
Effect Of Temperature ◽  
Rheological Models ◽  
Temperature Activation ◽  
Ugni Molinae

Abstract The rheological behaviour of purées and pulps from fresh and frozen-thawed murta (Ugni molinae Turcz) berries was studied at 30, 45, 60 and 75 °C. The Mitschka method was shown to be applicable to the murta berries, with its products showing non-Newtonian pseudoplastic behaviour. Rheological models as Ostwald-de Waele, Herschel-Bulkley, Bingham, Casson and Mizrahi-Berk fitted the experimental data with high values for correlation coefficients. Effect of temperature was evaluated using an Arrhenius-type equation. Compared to the murta pulp, the fresh or frozen-thawed murta purées had higher apparent viscosity at any shear rate and would undergo a more rapid change in viscosity with temperature. Activation energy for fresh and frozen-thawed purées were 22.335 kJ mol-1 (R2 = 0.9225), and 16.478 kJ mol-1 (R2 = 0.9654) respectively, while for fresh and frozen-thawed pulp Ea values of 8.967 kJ mol-1 (R2 = 0.9618) and 6.943 kJ mol-1 (R2 = 0.9773) were determined respectively.

The rheology of sewage sludge at different steps of treatment

1997 ◽  
Vol 36 (11) ◽  
pp. 79-85 ◽  
Author(s):  
V. Lotito ◽  
L. Spinosa ◽  
G. Mininni ◽  
R. Antonacci
Keyword(s):  
Sewage Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Rheological Behaviour ◽  
Rheological Parameters ◽  
Municipal Wastewater Treatment ◽  
Rotational Viscometer ◽  
Bingham Plastic ◽  
Solids Concentration ◽  
Municipal Wastewater Treatment Plants

Rheological parameters are very important in sewage sludge management, not only as designing parameters in transporting, storing, landfilling and spreading operations, but also as controlling ones in many treatments, such as stabilisation and dewatering. To study how different treatments affect sludge rheological behaviour, research has been undertaken at CNR-Istituto di Ricerca Sulle Acque (CNR-IRSA), and the preliminary results are discussed in this paper. Sludge samples taken from three municipal wastewater treatment plants at different steps of treatment have been tested by a rotational viscometer and data interpreted through both Bingham plastic and Ostwald pseudoplastic models. Coefficients of those models have been then correlated to solids concentration. Results confirmed that solids concentration is the main parameter affecting sludge rheology and evidenced that a single parameter is not sufficient to represent the rheological behaviour, thus indicating that other parameters should be introduced and characteristics considered for a better understanding of the phenomenon.

scholarly journals Functional and Rheological Properties of Piñuela (Bromelia karatas) in Two Ripening Stages.

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
María N. Osorio ◽  
Diego F. Moyano ◽  
Walter Murillo ◽  
Elizabeth Murillo ◽  
Albert Ibarz ◽  
...  
Keyword(s):  
Activation Energy ◽  
Superoxide Anion ◽  
Structural Changes ◽  
Arrhenius Equation ◽  
Rheological Behaviour ◽  
Physicochemical Characteristics ◽  
Rheological Parameters ◽  
Ripening Stage ◽  
Ripening Stages ◽  
Integrity Protection

Abstract The physicochemical characteristics and the activity of the polyphenol oxidase from piñuela fruit juices were determined at two ripening stages. The antioxidant capacity was evaluated by the superoxide anion yield. The ripening stage showed greater ability to inhibit ( $O_2^{. -}$ , 35.3 %). The inhibition of superoxide dismutase was higher for both ripe (88.29 %) and unripe (95.94 %) states. The rheological behaviour of the juice was satisfactorily described using Herschel-Bulkley model (R2 > 0.99). The concentration effect on the rheological parameters was described by the potential law model, and the temperature effect on the viscosity was described based on the Arrhenius equation, finding activation energy values from 11.94 and 17.80 kJ/mol. These results make Bromelia karatas L. a promissory fruit due to their content of secondary metabolites and its antioxidant activity, which could be associated to the presence of phenolic compounds, specifically flavonoids. Variations in these metabolites could also account for structural changes, physicochemical properties, the integrity protection of the fruit against adverse and an alternative to food products.

scholarly journals Analytical Rheology of Honey: A State-of-the-Art Review

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1709
Author(s):  
Célia Faustino ◽  
Lídia Pinheiro
Keyword(s):  
Sugar Content ◽  
Rheological Behaviour ◽  
Principal Component ◽  
Rheological Parameters ◽  
Experimental Conditions ◽  
Thixotropic Behaviour ◽  
Ancient Times ◽  
Medicinal Properties ◽  
Complex Relationships ◽  
Temperature Time

Honey has been used as a nutraceutical product since ancient times due to its nutritional and medicinal properties. Honey rheology influences its organoleptic properties and is relevant for processing and quality control. This review summarizes the rheological behaviour of honeys of different botanical source(s) and geographical locations that has been described in the literature, focusing on the relation between rheological parameters, honey composition (moisture, water activity, sugar content, presence of colloidal matter) and experimental conditions (temperature, time, stress, shear rate). Both liquid and crystallized honeys have been addressed. Firstly, the main mathematical models used to describe honey rheological behaviour are presented highlighting moisture and temperature effects. Then, rheological data from the literature regarding distinct honey types from different countries is analysed and results are compared. Although most honeys are Newtonian fluids, interesting shear-thinning and thixotropic as well as anti-thixotropic behaviour have been described for some types of honey. Rheological parameters have also been successfully applied to identify honey adulteration and to discriminate between different honey types. Several chemometric techniques have also been employed to obtain the complex relationships between honey physicochemical and rheological properties, including partial least squares (PLS), principal component analysis (PCA) and artificial neural networks (ANN).

Thermorheological Characterization of Elastoviscoplastic Carbopol Ultrez 20 Gel

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. A. Hassan ◽  
Manabendra Pathak ◽  
Mohd. Kaleem Khan
Keyword(s):  
Experimental Investigation ◽  
Yield Stress ◽  
Elastic Properties ◽  
Viscous Dissipation ◽  
Power Law ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Frequency Range ◽  
Power Law Index

The temperature and concentration play an important role on rheological parameters of the gel. In this work, an experimental investigation of thermorheological properties of aqueous gel Carbopol Ultrez 20 for various concentrations and temperatures has been presented. Both controlled stress ramps and controlled stress oscillatory sweeps were performed for obtaining the rheological data to find out the effect of temperature and concentration. The hysteresis or thixotropic seemed to have negligible effect. Yield stress, consistency factor, and power law index were found to vary with temperature as well as concentration. With gel concentration, the elastic effect was found to increase whereas viscous dissipation effect was found to decrease. Further, the change in elastic properties was insignificant with temperature in higher frequency range of oscillatory stress sweeps.

Applicability of power law for describing the rheology of soils of different origins and characteristics

2009 ◽  
Vol 46 (9) ◽  
pp. 1011-1023 ◽  
Author(s):  
Sueng Won Jeong ◽  
Serge Leroueil ◽  
Jacques Locat
Keyword(s):  
Strain Rate ◽  
Power Law ◽  
Debris Flows ◽  
Rheological Behaviour ◽  
Strain Rate Range ◽  
Rate Dependent ◽  
Different Origins ◽  
Power Law Index ◽  
Soil Behaviour ◽  
Low Activity

The rate-dependent rheological behaviour of soils of different origins and characteristics was studied and the applicability of the power law model was examined. The studied soils were divided into three groups: (i) low-activity soils, (ii) high-activity soils, and (iii) silt-rich soils. The results show that the power law applies to all these soils and is representative of soil behaviour in a strain rate range corresponding to debris flows, which is generally not the case with the Bingham model. For low-activity clays, the power law index, n, is typically equal to 0.12 and seems to increase with the plasticity index; it is larger (i.e., in the range of 0.2–0.6) for silt-rich soils. Comparison of n values for tests performed on intact and remoulded low-activity clay specimens indicates that the power law index is possibly strain-rate dependent.

ENTROPY INFLUENCE ON THE DEPENDENCE OF THE NANOFLUIDS VISCOSITY ON TEMPERATURE AND SHEAR RATE

2021 ◽  
Vol 7 (3) ◽  
pp. 89-105
Author(s):  
Lyudmila P. SEMIKHINA ◽  
Daniil D. Korovin
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Shear Rate ◽  
Viscous Flow ◽  
High Reliability ◽  
Narrow Particle Size Distribution ◽  
Disperse Systems ◽  
Rotational Viscometer ◽  
Surfactant Micelles ◽  
Dispersed Systems

A Brookfield DV-II + Pro rotational viscometer was used to study the viscosity of 7 samples of concentrated nanodispersed systems (nanofluids) with a similar viscosity (6-22 mPa ∙ s), the particles of the dispersed phase in which are nanosized surfactant micelles and conglomerates from them. It was found that for 5 out of 7 studied reagents, there is a decrease in viscosity typical for dispersed systems with an increase in the shear rate, and their flow curves, that is, the dependence of the shear stress on the shear rate, correspond to the ideal plastic flow of non-Newtonian fluids. Moreover, with high reliability, R2 ≥ 0.999 is described by the Bingham equation with a small value of the limiting shear stress (less than 0.2 Pa). It is shown that all the studied reagents are also characterized by an increase in the activation energy of a viscous flow Е with an increase in the shear rate. As a result, a decrease in viscosity with an increase in shear rate, typical for disperse systems, including nanofluids, is provided by a more significant increase in entropy changes ΔS compared to Е. It has been substantiated that, depending on the ratio between the activation energy of viscous flow Е and the change in entropy ΔS, the viscosity of concentrated micellar dispersed systems with an increase in the shear rate can decrease, remain unchanged, and increase. The last two cases, not typical for disperse systems and nanofluids, were identified and studied using the example of two demulsifiers, RIK-1 and RIK-2, with a maximum of a very narrow particle size distribution at 160 ± 5 nm, corresponding to the size of a special type of very stable micelles Surfactant — vesicle.

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