scholarly journals Rheological Behavior of Sumac (Rhus coriaria L.) Extract as Affected by Temperature and Concentration and Investigation of Flow Behavior with CFD

2020 ◽  
Vol 10 (6) ◽  
pp. 7120-7134
Keyword(s):  
Arrhenius Equation ◽  
Flow Behavior ◽  
Rheological Behaviour ◽  
Effect Of Temperature ◽  
Sudden Expansion ◽  
Flow Properties ◽  
Rotational Viscometer ◽  
Different Temperatures ◽  
Rhus Coriaria ◽  
Temperature Ranges

The purpose of this study is to investigate the rheological properties of sumac extract in different concentrations at different temperatures as well as its flow behavior in sudden expansion-contraction and at 90o elbow with CFD. The rheological behaviour of sumac extract in different concentrations (45.65%, 50.44%, 55.53%, 60.32%, and 65.13% total solids) were evaluated using a rotational viscometer at different temperatures (10, 20, 30, 40 and 50 C). Sumac extract samples showed Newtonian flow properties in these temperature ranges. Arrhenius equation was used to determine the effect of temperature. Ea value varied in the range of 11.16-34.35 kJ/mol, which diminished with a decrease in concentration. Power and Exponential models were used to characterize the effect of concentration on flow behavior. Time average velocity vector and contours, vorticity contours, kinetic energy contours, and pressure contours are given to show the flow behavior of sumac extract.

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.

Flow Behaviors of Commercial Food Thickeners Used for the Management of Dysphagia: Effect of Temperature

2012 ◽  
Vol 8 (2) ◽  
Author(s):  
Se-Ra Hong ◽  
Dong-Soo Sun ◽  
Whachun Yoo ◽  
Byoungseung Yoo
Keyword(s):  
Shear Stress ◽  
Yield Stress ◽  
Flow Behavior ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
High Shear ◽  
Flow Properties ◽  
Different Temperatures ◽  
Management Of Dysphagia ◽  
Arrhenius Temperature

Gum-based food thickeners are widely used to care for patients with dysphagia in Korea. In this study, the flow properties of commercially available gum-based food thickeners marketed in Korea were determined as a function of temperature. The flow properties of thickeners were determined based on the rheological parameters of the power law and Casson models. Changes in shear stress with the rate of shear (1-100 s-1) at different temperatures (5, 20, 35, and 50 oC) were independent of the type of thickener. All thickeners had high shear-thinning behavior (n=0.08-0.18) with yield stress at the different temperatures tested. In general, apparent viscosity (na,50) values progressively decreased with an increase in temperature. In addition, the consistency index (K) and Casson yield stress (σoc) values did not change much upon an increase in temperature from 5 to 35 oC, except for sample B. In the temperature range of 5-50 oC, the thickeners followed an Arrhenius temperature relationship with a high determination coefficient (R2=0.93-0.97): activation energies (Ea) for the flow of thickeners were in the range of 2.44 - 10.7 kJ/mol. Rheological parameters demonstrated considerable differences in flow behavior between the different gum-based food thickeners, indicating that their flow properties are related to the type of thickener and the flow properties of gum.

Effect of temperature and concentration on density and rheological properties of melon (Cucumis melo L. var. Inodorus) juice

2014 ◽  
Vol 44 (2) ◽  
pp. 168-178 ◽  
Author(s):  
Ali Mohamadi Sani ◽  
Ghazaleh Hedayati ◽  
Akram Arianfar
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Apparent Viscosity ◽  
Flow Behavior ◽  
Effect Of Temperature ◽  
Plastic Behavior ◽  
Linear Quadratic ◽  
Concentric Cylinder ◽  
Rotational Viscometer ◽  
Content Type

Purpose – The aim of this study was to measure the apparent viscosity, flow behavior and density of melon juice as a function of temperature and juice concentration and to obtain simple equations to correlate experimental data. Design/methodology/approach – Melon juice was concentrated in a rotary evaporator to 40±1, 52.5±1 and 65±1°Brix at 50°C, 80 rpm and stored at 4°C until analysis. Density of melon juice was determined with 25 ml pycnometer at 15, 25 and 35°C and was expressed as kg/m3. All experiments were conducted in triplicate. Experimental data were fitted to different models (linear, quadratic, exponential, quadratic exponential and polynomial) using Minitab 16. Significant differences in the mean values were reported at p<0.05. The flow behavior of melon juice was determined using a concentric cylinder rotational viscometer at shear rate range of 13.2-330 s−1 and temperatures of 15, 25 and 35°C. The experimental data were analyzed Slide Write V7.01 Trial Size (p<0.05) and the rheograms was plotted by Microsoft Excel 2007. Findings – Results showed that the four-term polynomial model is the best model for computing density values from temperature and concentration (R2=0.999). The measured shear stress was within 1.69-780 Pa, corresponding to viscosity range of 0.016-0.237 Pa · s. Within the tested conditions, the concentrate exhibited a pseudo plastic behavior. Temperature had an inverse effect on shear stress and apparent viscosity. Originality/value – No research had been done on production of melon juice concentrate.

Processing, rheology and structure of melt compounded PBTclay nanocomposites having different chemical composition.

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Luigi Scatteia ◽  
Paola Scarfato ◽  
Domenico Acierno
Keyword(s):  
Flow Behavior ◽  
Relaxation Times ◽  
Empirical Method ◽  
Effect Of Temperature ◽  
Gradual Transition ◽  
Flow Properties ◽  
Butylene Terephthalate ◽  
Melt Compounding ◽  
The Matrix ◽  
Twin Screw

AbstractIn this study the melt flow behavior of poly(butylene terephthalate)-clay nanocomposites produced by melt compounding was investigated. Four commercial organo-modified montmorillonites, differing mainly by the organic treatment used in the modification, were employed as nanometric fillers and blended with the poly(butylene terephthalate) (PBT) at two weight percentages each (6 and 9wt%). The process was carried out using a laboratory-scale twin-screw extruder at two different extrusion rates, in order to evaluate the effect of the shear rate during the process on microstructure and flow properties. In this regard, the nanocomposite samples were submitted to morphological analyses and rheological measurements in the dynamic regime. The effect of temperature on the flow behavior of the hybrids with respect to the neat PBT matrix was also investigated. The obtained data were related to the hybrid compositions and then to the chemical affinity between polymer and clay type. All the reported results have shown a gradual transition from a pseudo-Newtonian trend towards a pseudo-solid-like flow behavior with the increase of the clay loading and the dispersion/exfoliation level of the clay particles, due to the corresponding increase of the polymer-silicate interactions that slow the relaxation times of the PBT chains. Moreover, it was also evident that for the fillers having the higher affinity towards the PBT the nano-scale dispersion benefit from higher residence times, and therefore slower extrusion rates; on the contrary, for the fillers having poor interaction with the polymer, higher shear stress, and therefore higher extrusion rates, are needed to disrupt the clay tactoids in smaller particles. In the last part of the work, in order to verify if a relationship between flow properties and degree of exfoliation does actually exist, the rheological data were also processed using a simple semi-quantitative empirical method proposed in literature. The method failed for our systems, thus underlining the insufficiency of the rheological response alone in quantifying the exfoliation degree of an organoclay in the matrix.

scholarly journals Effect of temperature on passion fruit emergence and seedling vigor

2017 ◽  
Vol 39 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Antônio Gustavo de Luna Souto ◽  
Jussara Cristina Firmino da Costa ◽  
Nathalia Luiza Ferreira Campos ◽  
Jéssica Laísca Fernanda de Azevedo ◽  
Carlos Eduardo Magalhães dos Santos
Keyword(s):  
Dry Matter ◽  
Seedling Emergence ◽  
Thermal Conditions ◽  
Passion Fruit ◽  
Effect Of Temperature ◽  
Genetic Constitution ◽  
Growth Environment ◽  
Randomized Design ◽  
Different Temperatures ◽  
Temperature Ranges

Abstract: Seedlings for commercial growing of passion fruit are preferentially acquired through seeds. Success in germination and seedling emergence, in turn, is influenced by the genetic constitution of the progenies and the thermal conditions imposed on the growth environment. The aim of this study was to evaluate the emergence and vigor of seedlings of passion fruit cultivars exposed to different temperatures. The experiment was conducted in a germination chamber at the Unidade de Ensino, Pesquisa e Extensão / Pomar Campus of the Department of Plant Science of the Universidade Federal de Viçosa (UFV). The study was carried out in 5 × 3 factorial arrangement, with five temperature ranges (5-15, 10-20, 15-25, 20-30 and 25-35 °C) and three varieties of passion fruit (BRS Sol do Cerrado, BRS Gigante Amarelo and FB-200 Yellow Master) in a completely randomized design with six replications of 25 seeds per plot. The variables analyzed were the percentage, the speed index, and the average time of emergence, shoot length, total length, and seedling dry matter. The cultivars BRS Sol do Cerrado and BRS Gigante Amarelo exhibited seedling emergence of over 95% in the temperature ranges of 20-30 °C and 25-35 °C. Alternating temperatures from 20-30 °C stimulates seedling emergence, seedling growth, and greater accumulation of seedling dry matter.

scholarly journals Modelling of rheological behaviour of macaíba pulp at different temperatures

2022 ◽  
Vol 26 (3) ◽  
pp. 198-203
Author(s):  
Jéssica L. O. Brasileiro ◽  
Rossana M. F. de Figueirêdo ◽  
Alexandre J. de M. Queiroz ◽  
Regilane M. Feitosa
Keyword(s):  
Shear Rate ◽  
Arrhenius Equation ◽  
Rheological Behaviour ◽  
Temperature Variations ◽  
Average Percentage ◽  
Different Temperatures ◽  
Fluid Behaviour ◽  
Best Fit ◽  
Average Percentage Deviation ◽  
Viscosity Changes

ABSTRACT Fruit pulps undergo temperature variations during processing, leading to viscosity changes. This study aimed to analyse the rheological behaviour of macaíba pulp at different temperatures (10 to 50 ºC, with 5 ºC increments) and speeds (2.5 to 200 rpm, totalling 17 speeds). Experimental measurements were performed in a Brookfield viscometer, fitting the Ostwald-de-Waele, Mizrahi-Berk, Herschel-Bulkley, and Casson models to the experimental data of shear stress as a function of shear rate. Among the models used, the Mizrahi-Berk model (R² > 0.9656 and average percentage deviation - P ≤ 4.1%) was found to best fit the rheogram data. Macaíba pulp exhibited a non-newtonian behaviour and was characterised as pseudoplastic. It showed fluid behaviour indexes below unity under the studied conditions, with decreases in apparent viscosity as temperature and shear rate increased. Such behaviour could be described by the Arrhenius equation. The Mizrahi-Berk and Falguera-Ibarz models (R² > 0.99 and P ≤ 10%) best fitted the data and were used to represent the viscosity behaviour of macaíba pulp. The activation energy values of macaíba pulp ranged between 17.53 and 25.37 kJ mol-1, showing a rheological behaviour like other fruit pulps.

scholarly journals THE EFFECT OF TEMPERATURE ON THE LATENT PERIOD IN THE PHOTIC RESPONSE OF MYA ARENARIA

1919 ◽  
Vol 1 (6) ◽  
pp. 667-685 ◽  
Author(s):  
Selig Hecht
Keyword(s):  
Reaction Time ◽  
Latent Period ◽  
Environmental Temperature ◽  
Arrhenius Equation ◽  
Mya Arenaria ◽  
Effect Of Temperature ◽  
Photochemical Process ◽  
Principal Product ◽  
Different Temperatures ◽  
Photic Response

1. The effect of temperature on the reaction time of Mya to light is mainly confined to the latent period. The sensitization period, representing a photochemical process, is changed comparatively little. 2. The relation between the latent period and the temperature is adequately expressed by the Arrhenius equation, for temperatures below 21°C. Above this temperature, the latent period becomes increasingly longer than is required by the Arrhenius formula when µ = 19,680. 3. These deviations, occurring above the highest environmental temperature of Mya, are explained on the assumption that the principal product formed during the latent period is inactivated by heat. 4. Calculation of the velocity of the hypothetical inactivation reaction at different temperatures shows that it also follows the Arrhenius rule when µ = 48,500. This value of µ corresponds to those generally found for spontaneous inactivations and destructions.

Kinetics of Hydrothermal Decomposition of Potassium Feldspar with Calcium Hydroxide

2012 ◽  
Vol 549 ◽  
pp. 65-69 ◽  
Author(s):  
Yu Qin Liu ◽  
Hong Tu Xia ◽  
Hong Wen Ma
Keyword(s):  
Activation Energy ◽  
Kinetic Equation ◽  
Calcium Hydroxide ◽  
Arrhenius Equation ◽  
Hydrothermal Reaction ◽  
Potassium Feldspar ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Dissolution Ratio ◽  
Kinetics Of

The aegirine-augite syenite potash ore, taken from Changling, Luonan in Shannxi province, were hydrothermally decomposed over the temperature ranges of 533 K to 563 K using calcium hydroxide as additive. The dissolution ratio of the K2O at different reaction temperature and time was determined. Analysis of the experimental results revealed that the dissolution rate of potash ore satisfies the chemical reaction controlled kinetic equation. The rate constant of hydrothermal reaction at different temperatures was obtained. The activation energy was calculated using the Arrhenius equation. The hydrothermal decomposition mechanism of microcline was proposed.

5-hydroxymethyl furfural formation and reaction kinetics of different pekmez samples: effect of temperature and storage

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Rasim Alper Oral ◽  
Mahmut Dogan ◽  
Kemal Sarioglu ◽  
Ömer Said Toker
Keyword(s):  
Reaction Kinetics ◽  
Arrhenius Equation ◽  
Storage Period ◽  
Effect Of Temperature ◽  
Temperature Changes ◽  
Juniperus Communis ◽  
Hydroxymethyl Furfural ◽  
Different Temperatures ◽  
And Storage ◽  
Kinetics Of

Abstract Pekmez (molasses) is a traditional food commonly produced from grape and other kind of fruit juices by evaporation processes. In this study, 5-Hydroxymethylfurfural (HMF) level of various pekmez samples was investigated during storage at different temperatures. HMF content of apricot, mulberry, carob, grape, Juniperus communis pekmez changed from 133.0 ppm to 1060.5 ppm, from 88.2 to 1921.5 ppm, from 11.1 to 1153.6 ppm, from 75.5 to 2077.0 ppm, from 19.9 to 280.1 ppm throughout eight months storage period, respectively. Samples of pekmez from the Juniperus communis had the minimum k values for each temperature that means HMF formation in these samples were slower than other pekmez types. The kinetic data analysis for HMF formation during storage was performed and an Arrhenius equation was used to determine the effect of temperature on reaction kinetics of 5-HMF formation in pekmez samples. Ea values were found between 10.58–37.73 (kcal/mol). Apricot pekmez was found as the least sensitive sample to HMF formation resulted from temperature changes.

Rheological behaviour of dextran sulfate solutions

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Asgar Farahnaky ◽  
Zahra Allahdad ◽  
Mahmoud Aminlari ◽  
Mahsa Majzoobi ◽  
Hamed Askari ◽  
...  
Keyword(s):  
Dextran Sulfate ◽  
Rheological Behaviour ◽  
Flow Behaviour ◽  
Newtonian Flow ◽  
Rotational Viscometer ◽  
Shear Rates ◽  
Sulfate Solutions ◽  
Different Temperatures ◽  
Power Law Equation ◽  
Plate Geometry

Abstract The purpose of this research was to study the rheological behaviour of dextran sulfate solutions under different conditions. A PC controlled rotational viscometer with a cone and plate geometry equipped with a temperature controlled unit was used to measure apparent viscosity of dextran solutions at different temperatures (25, 40 and 60 oC) and concentrations (2, 5, 10 and 20%). Viscosity tests of dextran sulfate solutions were performed at a range of shear rates (8-230 1/s) and the rheological data were fitted using the Power Law equation to get consistency and flow behaviour indices. The results indicated that all dextran sulfate solutions showed Newtonian flow behaviour. The viscosity of dextran sulfate solutions was significantly affected by temperature, e.g. the viscosity of a 5% solution at 25, 40 and 60 oC was 16.7, 12.7 and 10.7 mPa.s, respectively.

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