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.

Effect of temperature on the rheological behavior of sugary cassava

2020 ◽  
pp. 125
Author(s):  
Leiliane do Socorro Sodré Souza ◽  
Tatiane Pereira de Souza ◽  
Rafael Lopes e Oliveira ◽  
Sérgio Duvoisin Junior ◽  
Ari de Freitas Hidalgo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Food Production ◽  
Arrhenius Equation ◽  
Effect Of Temperature ◽  
Rheological Models ◽  
Rate Range ◽  
Fermented Beverages ◽  
Three Samples

The rheological behavior of the juice extracted from sugary cassava roots, a type of cassava that stored the largest amount of sugars and the starch as it was, at various temperatures (9-65ºC) and in concentrations of 5ºBrix, 10.5ºBrix, and 18.5ºBrix. The experiments were performed on a Brookfield viscometer in a shear rate range of 0.01-237.6 s-1. The rheological models of Newton, Bingham, and Ostwald-De-Waele were fitted to the experimental results. The Newton model describes well the rheological behavior of the three samples evaluated. The effect of temperature on viscosity was evaluated using an Arrhenius equation; the viscosity value is influenced by the same temperature. The activation energy values ​​for the concentrations of 5ºBrix, 10.5ºBrix and 18.5ºBrix correspond to 3.14 kcal mol-1, 3.53 kcal mol-1 and 3.71 kcal mol-1. This type of cassava can be used in the production of ethanol, fermented beverages and syrups. It is also an important alternative for food production, as the cultivation of cassava can be classified as less aggressive to the environment, in comparison with sugarcane.

Rheological behaviour of enzyme clarified Indian gooseberry juice

2012 ◽  
Vol 26 (2) ◽  
pp. 145-151 ◽  
Author(s):  
S. Manjuantha ◽  
P. Raju ◽  
A. Bawa
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Viscous Flow ◽  
Rheological Behaviour ◽  
Soluble Solids ◽  
Effect Of Temperature ◽  
Exponential Equation ◽  
Indian Gooseberry ◽  
Solids Concentration ◽  
Soluble Solids Concentration

Rheological behaviour of enzyme clarified Indian gooseberry juiceThe rheological behaviour of enzyme clarified depectinated Indian gooseberry juice and its concentrate was studied as a function of total soluble solids concentration in the range of 8.2 to 35.9°Bx and temperatures from 20 to 80°C using coaxial controlled stress rheometer up to a shear rate of 600 s-1. The results indicated that the enzyme clarified gooseberry juice behaves like a Newtonian fluid with a viscosity ranging from 3.92 to 7.94 mPa s. The effect of temperature on viscosity of different concentration of juice was described by an Arrhenius type relationship (R >0.99). The activation energy for viscous flow was found to be in the range 4.34 to 5.37 KJ mol-1depending upon the concentration of the juice. The activation energy of viscous flow on concentration was modeled by exponential equation (R>0.99). The effect of concentration on viscosity followed an exponential type relationship (R>0.98) at the temperature used.

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.

The Kinetic Study of H2S Formation and Desorption on the S/Pt(111) Surface by Computer Simulation

2003 ◽  
Vol 10 (05) ◽  
pp. 745-750 ◽  
Author(s):  
A. Z. Moshfegh ◽  
K. H. Zakeri
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Computer Simulation ◽  
Random Walk ◽  
Kinetic Study ◽  
Maximum Amount ◽  
Effect Of Temperature ◽  
Desorption Rate ◽  
Mechanism Of Formation ◽  
Maximum Value

In this investigation, we have studied the kinetics and mechanism of formation and desorption of H 2 S on the Pt (111) surface using a kinetic random walk model. The effect of temperature on the H 2 S formation was studied in the range of 85–150 K. It was observed that a maximum amount of H 2 S is formed at 90 K and the amount is reduced at higher temperatures. H 2 S production yield as a function of time at different initial sulfur coverage ranging from 0.02 to 0.33 ML (1 ML ≃ 1 × 1015 atoms/cm 2) was also examined. It was obvious that as the initial S coverage increases, the rate of H 2 S formation rapidly increases and reaches a maximum value and then declines gradually. Furthermore, according to our simulated TPD spectra, for β = 1 K/s the maximum desorption rate occurs at Tp = 107.2 K . In addition, analysis of simulated TPD spectra of H 2 S desorption showed in an activation energy of H 2 S desorption Ed = 27.2 kcal/mol . Finally, the obtained simulated results were compared with the experimental data reported very recently, showing excellent agreement.

scholarly journals Comportamento reológico de iogurte de cajá comercializado em Campina Grande, Paraíba

2015 ◽  
Vol 10 (2) ◽  
pp. 257-260
Author(s):  
Flávio Farias Gurjão ◽  
Gilmara Gurjão Carneiro ◽  
Taciano Pessoa ◽  
Débora Rafaelly Soares Silva ◽  
Patricia Rodrigues Pê
Keyword(s):  
Molecular Structure ◽  
Rheological Behavior ◽  
Correlation Coefficients ◽  
Effect Of Temperature ◽  
Rheological Models ◽  
Rheological Study ◽  
Rheological Data ◽  
Different Temperatures ◽  
Hog Plum ◽  
Fluid Characteristics

O estudo reológico contribui para o conhecimento da estrutura molecular, no controle de qualidade e aceitação de um determinado produto, auxilia no controle do processo industrial e em projetos de equipamentos no processamento dos materiais. Objetivou-se avaliar o comportamento reológico de iogurte de cajá e a adequação dos dados reológicos aos modelos de Ostwald-de-Waele, Herschel-Bulkley e Mizrahi-Berk e ainda o efeito da temperatura sobre o comportamento reológico. Os dados reológicos foram obtidos através de um viscosímetro Brookfield DV-II+Pro. Os ensaios foram realizados nas temperaturas 20, 30 e 40 °C e os resultados experimentais foram ajustados pelos modelos de Ostwalde-de-Waelle, Casson, Hershel Bulkey e Mizrahi-Berk, com auxílio do software STATISTICA, versão 7.0. O iogurte analisado neste experimento apresentou comportamento de fluido não newtoniano com características pseudoplástica. Os modelos reológicos de Hershel Bulkey e Mizrahi-Berk representaram satisfatoriamente o comportamento reológico do iogurte de cajá nas diferentes temperaturas estudadas, apresentando coeficientes de correlação (R²), acima de 0,99. Rheological properties of yogurt cajá marketed in Campina Grande, state ParaíbaAbstract: The rheological study contributes to the knowledge of the molecular structure, the quality control and acceptance of a particular product, helps to control the manufacturing process and equipment designs in the processing of materials. This study aimed to evaluate the rheological behavior of yogurt cajá and the adequacy of the rheological data to models of Ostwald-de-Waele, Herschel-Bulkley and Mizrahi-Berk still the effect of temperature on the rheological behavior. The rheological data were obtained using a Brookfield DV-II + Pro. Assays were carried out at temperatures 20, 30 and 40 °C and the experimental results were adjusted by the model-to-Ostwalde Waelle, Casson and Herschel Bulkey Mizrahi-Berk, using the STATISTICA software, version 7.0. The yogurt analyzed in this experiment showed behavior of pseudoplastic non-Newtonian fluid characteristics. The rheological models Hershel Bulkey and Mizrahi-Berk satisfactorily represented the rheological behavior of the hog plum yogurt at different temperatures studied, with correlation coefficients (R²) above 0.99.

Effect of ionizing radiation on the kinetics of hydrogenation on the Ni-MgO mixed catalyst

1982 ◽  
Vol 47 (7) ◽  
pp. 1780-1786 ◽  
Author(s):  
Rostislav Kudláček ◽  
Jan Lokoč
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Liquid Phase ◽  
Ionizing Radiation ◽  
Oxide Catalyst ◽  
Absorbed Dose ◽  
Hydrogenation Rate ◽  
Solution Composition ◽  
Mixed Catalyst ◽  
Kinetics Of

The effect of gamma pre-irradiation of the mixed nickel-magnesium oxide catalyst on the kinetics of hydrogenation of maleic acid in the liquid phase has been studied. The changes of the hydrogenation rate are compared with the changes of the adsorbed amount of the acid and with the changes of the solution composition, activation energy, and absorbed dose of the ionizing radiation. From this comparison and from the interpretation of the experimental data it can be deduced that two types of centers can be distinguished on the surface of the catalyst under study, namely the sorption centres for the acid and hydrogen and the reaction centres.

scholarly journals Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

2016 ◽  
Vol 20 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Hellismar W. da Silva ◽  
Renato S. Rodovalho ◽  
Marya F. Velasco ◽  
Camila F. Silva ◽  
Luís S. R. Vale
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Removal Rate ◽  
Effective Diffusion ◽  
Drying Time ◽  
Three Samples ◽  
Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

DOM Products: Activation Energy Estimation and Reliability Assessment

2013 ◽  
Vol 470 ◽  
pp. 781-784 ◽  
Author(s):  
Chien Yi Huang ◽  
Yueh Hsun Lin ◽  
Eric Huang
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Subjective Experience ◽  
Reliability Assessment ◽  
Life Time ◽  
Service Condition ◽  
Energy Estimation ◽  
Failure Data ◽  
Scientific Approach ◽  
Temperature Scenario

A scientific approach is proposed in this research to investigate a disk on module (DOM) product's activation energy based on experimental data that eliminates subjective experience. This study considers multiple temperature conditions to enhance the accuracy of activation energy estimation. In order to ensure the consistency of failure mode in each temperature scenario, the slopes of Weibul probability plots obtained from the failure data are calculated followed by an examination for parallelism. The estimated life time under normal service condition differs from the results obtained using the industrial standard given activation energy by approximately 42%.

Diffusion Coefficients of Interest for the Simulation of Heat Treatment in Rare-Earth Transition Metal Magnets

2012 ◽  
Vol 727-728 ◽  
pp. 163-168 ◽  
Author(s):  
Marcos Flavio de Campos
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
Activation Energy ◽  
Rare Earth ◽  
Transition Metal ◽  
Impurity Atom ◽  
Diffusion Coefficients ◽  
Arrhenius Equation ◽  
Atom Diffusion ◽  
Essential Input

In the case of the modeling of sintering and heat treatments, the diffusion coefficients are an essential input. However, experimental data in the literature about diffusion coefficients for rare-earth transition metal intermetallics is scarce. In this study, the available data concerning diffusion coefficients relevant for rare-earth transition metal magnets are reviewed and commented. Some empirical rules are discussed, for example the activation energy is affected by the size of the diffusing impurity atom. Diffusion coefficients for Dy, Nd and Fe into Nd2Fe14B are given according an Arrhenius equation D=D0exp (-Q/RT). For Dy diffusion into Nd2Fe14B, Q 315 kJ/mol and D08 . 10-4m2/s.

scholarly journals Photocatalytic Degradation of Textile Dyeing Wastewater Using Titanium Dioxide and Zinc Oxide

2008 ◽  
Vol 5 (2) ◽  
pp. 219-223 ◽  
Author(s):  
Abbas J. Attia ◽  
Salih H. Kadhim ◽  
Falah H. Hussein
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Irradiation Time ◽  
Effect Of Temperature ◽  
Dyeing Wastewater ◽  
Textile Dyeing ◽  
Textile Factory ◽  
Textile Dyeing Wastewater

Photodegradation of a real textile dyeing wastewater taken from Hilla textile factory in Babylon Governorate, Iraq have been investigated. Photocatalytic degradation was carried out over suspensions of titanium dioxide or zinc oxide under ultraviolet irradiation. Photodegradation percentage was followed spectrophometrically by the measurements of absorbance at λmax equal to 380 nm. The rate of photodegradation increased linearly with time of irradiation when titanium dioxide or zinc oxide was used. A maximum color removal of 96% was achieved after irradiation time of 2.5 hours when titanium dioxide used at 303K and 82% color reduction was observed when zinc oxide used for the same period and at the same temperature. The effect of temperature on the efficiency of photodegradation of dyestuff was also studied. The activation energy of photodegradation was calculated and found to be equal to 21 ± 1 kJ mol-1 on titanium dioxide and 24 ± 1 kJ mol-1 on zinc oxide.

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