Time Dependent Rheological Characteristics of Pineapple Jam

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Santanu Basu ◽  
US Shivhare ◽  
GSV Raghavan
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Time Dependent ◽  
Rheological Characteristics ◽  
Fruit Pulp ◽  
Flow Properties ◽  
Thixotropic Behavior ◽  
Dependent Flow

Jam is an intermediate moisture food containing fruit pulp, pectin, sugar and acid. The effect of sugar and pectin concentration, pH, shear rate and temperature on the time dependent rheological properties of pineapple jam was studied using a rheometer. Pineapple jam exhibited thixotropic behavior. Shear stress of the pineapple jam at a particular time of shearing depended on the shear rate, temperature and composition. Weltman, Hahn, and Figoni and Shoemaker, models were applied to describe the time dependent flow properties of pineapple jam. Hahn model described adequately the rheological characteristics of pineapple jam.

The Rheological Properties of Turkish Delight

2009 ◽  
Vol 6 (1) ◽  
Author(s):  
Zurriye Yilmaz ◽  
Mehmet Dogan ◽  
Mahir Alkan ◽  
Serap Dogan
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Power Law ◽  
Food Industry ◽  
Arrhenius Equation ◽  
Flow Behavior ◽  
Effect Of Temperature ◽  
Flow Properties ◽  
Different Temperatures ◽  
Dependent Flow

In the food industry, rheological properties, such as viscosity, shear rate, and shear stress, are the most important parameters required in the design of a technological process. Therefore, in this study, we determined the flow behavior and the time-dependent flow properties of Turkish Delight (TD) in the temperature range of 25-75°C using a capillar rheometer. The structure and thermal properties of TD were investigated by XRD and a simultaneous DTA/TG analysis. The shear rate values ranged from 5 to 300s-1. We found that: (i) TD behaved as non- Newtonian pseudoplastic foodstuff; (ii) while the measurement temperature increased, viscosity decreased; and (iii) TD was a rheopectic material. The effect of temperature on viscosity was described by means of the Arrhenius equation. The activation energies for the flow of pseudoplastic TD varied from 50.1-74.2 kJ/mol, depending on shear rate. Three models were used to predict the flow behavior of TD, namely, the Power law, Bingham and Casson models. The Power law model adequately described well the flow behavior of TD at different temperatures.

Modelling of Drilling Fluid Thixotropy

2018 ◽  
Author(s):  
Eric Cayeux ◽  
Amare Leulseged
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Time Dependence ◽  
Rheological Properties ◽  
Drilling Fluid ◽  
Time Dependent ◽  
Drilling Fluids ◽  
Shear Rates ◽  
Pump Flow Rate ◽  
Drilling Operations

Drilling fluids are visco-elastic materials, i.e. they behave as a viscous fluid when subject to a sufficient shear stress and like an elastic solid otherwise. Both their elastic and viscous properties are time-dependent, i.e. drilling fluids are thixotropic. Because of thixotropy, it takes a finite time before the effective viscosity of a drilling fluid attains an equilibrium when the fluid is subject to a change of shear rate. This effect is visible when one changes the applied shear rate in a rheometer, as the fluid will gradually adapt to the new shearing conditions. When the velocity of a drilling fluid changes, for instance due to a change in pump flow rate, movement of the drill string, or change of flow geometry, the fluid will exhibit a time-dependent response to the new shearing conditions, requiring a certain time to reach the new equilibrium condition. Unfortunately, the time-dependence of the rheological properties of drilling fluids are usually not measured during drilling operations and therefore it is difficult to estimate how thixotropy impacts pressure losses in drilling operations. For that reason, we have systematically measured the time-dependence of the rheological properties of several samples of water-based, oil-based and micronized drilling fluids with a scientific rheometer in order to capture how drilling fluids systems respond to variations of shear rates. Based on these measurements, we propose to investigate how one existing thixotropic model manages to predict the shear stress as a function of the shear rate while accounting for the shear history and gelling conditions. Then we propose a modified model that fits better, overall, with the measurements even though there are still noticeable discrepancies, especially when switching back to low shear rates.

scholarly journals Rheological properties of liquid ebonite compositions filled with shungite

2021 ◽  
pp. 65-70
Author(s):  
Y.M. Pushkarev ◽  
◽  
S.V. Saitarly ◽  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Viscous Flow ◽  
Rheological Properties ◽  
Flow Properties

The effect of shungite on the structural and viscous-flow properties of compositions based on oligobutadiene was studied. The strength of coagulation structures of ebonite compositions filled with shungite was determined. The critical filling concentration was established and it is 40 wt.% of shungite per 100 wt.% of oligobutadiene. It was shown that increasing the temperature from 200C to 800C leads to a significant reduction in the shear stress required to destroy the structure of the composition. Temperature and shear rate independently affect the structured composition. Thus, it was shown that shungite powder can be used as a filler in liquid ebonite compositions based on oligobutadiene.

scholarly journals The influence of base oil type on the rheological properties of ecological lubricating greases

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (2) ◽  
pp. 127-135
Author(s):  
Rafał Kozdrach ◽  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Measurement Data ◽  
Measuring System ◽  
Rheological Parameters ◽  
Flow Curves ◽  
Lubricating Grease ◽  
Dispersion Phase ◽  
Base Oil

The article presents the results of research on the influence the type of base oil in lubricating compositions has on the rheological parameters of selected lubricants. Vegetable, mineral, and synthetic dispersion phases were used to produce lubricating greases. The modified amorphous silica was used as the dispersed phase. However, as a modifying additive was used a substance containing the antioxidants, corrosion inhibitors, and EP/AW additives. The experiments on rheological properties were carried out using a Physica MCR 101 rotational rheometer (manufactured by Anton Paar), equipped with a diffusion air bearing and connected to a pneumatic supply – an oil-free Jun-Air compressor and air drying block. The device is equipped with a Peltier system for temperature control in the range of –20°C to 200°C and an external thermostatic VISCOTHERM V2 system, working in the temperature range of –20°C to 200°C. The rheometer control and measurement data analysis were performed using Rheoplus software. The tests were carried out using a cone-plate measuring system with a shear rate range of 0.01–100 s-1 at 20°C for lubricating compositions prepared on various oil bases. To evaluate the value of rheological parameters, the results of tests of the dependence between shear stress and shear rate (flow curves) were used. For the theoretical determined on the flow curves, the following rheological models were used: Bingham, Herschel–Bulkley, Casson, and Tscheuschner. The values of the shear stress (yield point) in depending on the type of dispersion phase has changed. This proves that the use of a base oil with the appropriate functional properties does not weaken, but reinforces the spatial structure of a lubricating grease. It has an important meaning when selecting construction parameters when designing a central lubrication system with grease made from a vegetable oil base (Abyssinian oil). The rheological properties of the lubricating grease are influenced by the type of base oil and thickener, any additives in the grease, the production technology of the grease, and the conditions in which it is used. The tests revealed an important influence of the base oil on the rheological parameters that describe the behaviour of lubricating compositions subjected to stresses and strains in a lubricating system.

Influence of fibrinogen on flow properties of erythrocyte suspensions

1964 ◽  
Vol 207 (5) ◽  
pp. 1035-1040 ◽  
Author(s):  
Roe E. Wells ◽  
Thomas H. Gawronski ◽  
Paul J. Cox ◽  
Richard D. Perera
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Cell Aggregation ◽  
Cell Suspensions ◽  
Fibrinogen Concentration ◽  
Sedimentation Rates ◽  
Cell Aggregates ◽  
Red Cell ◽  
Flow Properties ◽  
Yield Value

The influence of fibrinogen on the flow properties of red cell suspensions (hematocrit 41) was studied by viscometry at low rates of shear (0.1–20 sec–1). These findings were correlated with sedimentation rates and photomicrographical studies of cell aggregation. Fibrinogen concentration was varied from 0.3 to 2.0 g/100 ml. The viscosity of the pure solutions of fibrinogen was independent of shear rate, ranging from 0.87 to 1.7 centipoise (cp) at 37 C. The viscosity of the cell suspensions at 10 sec–1 varied from 4.3 cp in 0.3 g/100 ml fibrinogen to 14 cp in 2 g/100 ml fibrinogen. All suspensions were markedly dependent on shear rate, viscosity increasing in exponential-like fashion as shear rate decreased. Extrapolation of plots of shear stress1/2 versus shear rate1/2 revealed the suspensions to sustain a finite stress without deformation or flow, the "yield value" increasing as fibrinogen concentration increased. Photomicrographs of dilute cell suspensions revealed the formation of cell aggregates and rouleaux, increasing in size and descent velocity as fibrinogen concentration increased.

scholarly journals Rheological properties of sugarfree milk chocolate: Comparative study and optimisation

2017 ◽  
Vol 35 (No. 5) ◽  
pp. 440-448 ◽  
Author(s):  
Rasouli-Pirouzian Haniyeh ◽  
Peighardoust Seyed Hadi ◽  
Azadmard-Damirchi Sodeif
Keyword(s):  
Rheological Properties ◽  
Good Alternative ◽  
Casson Fluid ◽  
Bulking Agents ◽  
Rheological Characteristics ◽  
Flow Properties ◽  
Milk Chocolate ◽  
Simplex Lattice ◽  
Simplex Lattice Mixture Design ◽  
Different Levels

The effects of sugar substitutes on rheological characteristics of compound milk chocolate using a simplex-lattice mixture design were evaluated. For this purpose, two bulking agents (maltitol and xylitol) at different levels (0–100%) were used and ten formulations were examined in order to find the optimum levels. All chocolate samples showed shear thinning behaviour. It was found that compound milk chocolate behaved as a Casson fluid. Chocolate formulations containing the highest maltitol substitution resulted in similar flow properties compared to those of the control and hence can be a good alternative. The results demonstrated that chocolate combinations containing 87.8% maltitol and 12.2% xylitol were found as the optimum concentrations producing the most acceptable rheological properties.

Preparation of Magnetorheological Fluid and Study on Its Rheological Properties

2014 ◽  
Vol 13 (02) ◽  
pp. 1450009 ◽  
Author(s):  
Shreedhar Kolekar
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Rheological Properties ◽  
Magnetorheological Fluid ◽  
Magnetic Flux Density ◽  
Iron Loading ◽  
Iron Particles ◽  
Mr Fluid ◽  
Carrier Fluid ◽  
System Type

The present paper focuses on preparation and process of the magnetorheological (MR) fluid whose carrier fluid is silicone-based oil and its additive is the commercial grease with different concentration of iron particles. General properties of MR fluid are discussed and rheological properties like shear rate, shear stress, viscosity of MR fluid can be found by using cone-and-plate sensor system-type rheometer. The result shows that shear stress as a function of magnetic flux density and viscosity does not strictly scale with iron loading.

scholarly journals Viscosity sinergism of hydrozypropmethyl and carboxy methyl cellulose

2008 ◽  
Vol 62 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Jaroslav Katona ◽  
Verica Sovilj ◽  
Lidija Petrovic
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Binary Mixtures ◽  
Methyl Cellulose ◽  
Mass Ratio ◽  
Positive Deviation ◽  
Flow Properties ◽  
Concentration Changes ◽  
Overlap Concentration ◽  
Carboxy Methyl

Rheology modifiers are common constituents of food, cosmetic and pharmaceutic products. Often, by using two or more of them, better control of the product rheological properties can be achieved. In this work, rheological properties of hydroxypropymethyl cellulose (HPMC) and sodium carboxymethyl cellulose (NaCMC) solutions of different concentrations were investigated and compared to the flow properties of 1% HPMC/NaCMC binary mixtures at various HPMC/NaCMC mass ratios. Solutions of HPMC and NaCMC were found to be pseudoplastic, where pseudoplasticity increases with increase in the macromolecules concentration. Changes of the degree of pseudoplasticity, n as well as the coefficient of consistency, K with the concentration are more pronounced in HPMC solutions when compared to the NaCMC ones. This is mostly due to the ability of HPMC molecules to associate with each other at concentrations above critical overlap concentration, c , and greater flexibility of macromolecular chains. Binary mixtures of HPMC/NaCMC were also found to be pseudoplastic. Experimentally obtained viscosities of the mixture were proved to be larger than theoretically expected ones, indicating viscosity synergism as a consequence of HPMC-NaCMC interaction. Maximum in synergy was observed when HPMC/NaCMC mass ratio was 0.4/0.6, no matter of the shear rate applied. On the other hand, it was found that relative positive deviation, RPD decreases when shear rate is increased.

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