scholarly journals Aqueous Solutions of Polyethoxylated Fatty Alcohols Rheological behavior and superficial properties

2019 ◽  
Vol 70 (2) ◽  
pp. 382-386
Author(s):  
Andra Tamas ◽  
Sabina Nitu
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Aqueous Solutions ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Fatty Alcohols ◽  
Flow Behavior Index ◽  
Foaming Power ◽  
Newtonian Behavior ◽  
Behavior Index

The paper presents the study of the rheological and superficial behavior (foaming power and wetting capacity) of some aqueous solutions with polyethoxylated fatty alcohols content. The influence of fatty alcohols concentration and their degree of ethoxylation as well as that of temperature on the rheological behavior was determined from the dependences between the shear stress t and the shear rate. The results demonstrate that all the studied solutions have non-Newtonian behavior, with flow behavior index smaller than 1.

scholarly journals Caesalpinia pulcherrima seed galactomannan on rheological properties of dairy desserts

2020 ◽  
Vol 50 (6) ◽  
Author(s):  
Stella Regina Arcanjo Medeiros ◽  
Victor Alves de Oliveira ◽  
Amanda Mazza Cruz de Oliveira ◽  
Marjory Lima Holanda Araujo ◽  
Judith Pessoa de Andrade Feitosa ◽  
...  
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Milk Protein ◽  
Flow Behavior ◽  
Flow Behavior Index ◽  
N Yield ◽  
Dynamic Rheological Behavior ◽  
Behavior Index

ABSTRACT: Dairy desserts containing Caesalpinia pulcherrima seed galactomannan were evaluated to determine their static and dynamic rheological behaviors. Variations in consistency index (k), flow behavior (n), yield stress and thixotropy of the desserts indicated that the galactomannan caused an increase in the shear stress and apparent viscosity of the system. All samples exhibited shear-thinning behavior with flow behavior index values (n) between 0.06 and 0.37. Dynamic rheological behavior was evaluated for MD (high solid levels) and MD/2 (half the amount of solids) groups, and both G’ and G’’ moduli were depended on the frequency. The MD and MD/2 groups showed variations in the elastic modulus (G’) throughout the temperature range (mainly at 50 °C), showing greater sensitivity at high temperatures. C. pulcherrima galactomannan was able to promote synergism with starch, milk protein and sucrose and to improve the development of stronger and more resistant gels.

Electroosmotic Flow of Power-Law Fluids in a Slit Microchannel

2009 ◽  
Author(s):  
Cunlu Zhao ◽  
Chun Yang
Keyword(s):  
Shear Stress ◽  
Double Layer ◽  
Power Law ◽  
Dynamic Viscosity ◽  
Electroosmotic Flow ◽  
Flow Behavior ◽  
Flow Behavior Index ◽  
Power Law Fluids ◽  
Hyperbolic Cosine ◽  
Behavior Index

Electroosmotic flow of power-law fluids in a slit channel is analyzed. The governing equations including the linearized Poisson–Boltzmann equation, the Cauchy momentum equation and the continuity equation are solved to seek analytical expressions for the shear stress, dynamic viscosity and velocity distributions. Specifically, exact solutions of the velocity distributions are explicitly found for several special values of the flow behavior index. Furthermore, with the implementation of an approximate scheme for the hyperbolic cosine function, approximate solutions of the velocity distributions are obtained. In addition, a mathematical expression for the average electroosmotic velocity is derived for large values of the dimensionless electrokinetic parameter, κH, in a fashion similar to the Smoluchowski equation. Hence, a generalized Smoluchowski velocity is introduced by taking into account contributions due to the finite thickness of the electric double layer and the flow behavior index of power-law fluids. Finally, calculations are performed to examine the effects of κH, flow behavior index, double layer thickness, and applied electric field on the shear stress, dynamic viscosity, velocity distribution, and average velocity/flow rate of the electroosmotic flow of power-law fluids.

Study of the Rheological Parameters of Honey Using the Mitschka Method

2009 ◽  
Vol 5 (3) ◽  
Author(s):  
Charles Windson Isidoro Haminiuk ◽  
Giselle M. Maciel ◽  
Manuel Salvador Vicente Plata-Oviedo ◽  
Alessandra Quenehenn ◽  
Agnes P Scheer
Keyword(s):  
Quality Control ◽  
Shear Stress ◽  
Shear Rate ◽  
Temperature Effect ◽  
Rheological Behavior ◽  
Food Industry ◽  
Experimental Results ◽  
Rheological Parameters ◽  
Quality Control Testing ◽  
Newtonian Behavior

In this work the rheological behavior of two varieties of honey were evaluated using a Brookfield viscometer R.V.T in a temperature range of 5-20°C. In order to interpret the experimental results in terms of viscosity, the torque-speed data and scale readings were converted into shear stress-shear rate relations using numerical conversion values proposed by Mitschka. This method offers excellent potential for quality control testing in the food industry. Samples exhibited Newtonian behavior and the temperature effect on the viscosity followed an Arrhenius-type relationship.

scholarly journals Rheological and functional properties of Roselle (Hibiscus sabdariffa) leaves puree

10.5219/929 ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 46-57
Author(s):  
Jaga Mohan Meher ◽  
Bidyut Mazumdar ◽  
Amit Keshav
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Flow Behavior ◽  
Hibiscus Sabdariffa ◽  
Temperature Level ◽  
Flow Behavior Index ◽  
Rheological Models ◽  
Rheological Analysis ◽  
Ir Analysis ◽  
Behavior Index

Pureed form of leaves (Hibiscus sabdariffa L. (Roselle)) was taken for physicochemical and rheological analysis at temperatures and TSS range of 278 K - 318 K and 3 - 5 °Brix respectively. The steady-state rheological analysis was performed with a shear rate of 1 - 100 s-1. Different rheological models are tried; Power-law was best fitted with the experimental data (R2 ≥0.98). Temperature dependence of viscosity was found out using an Arrhenius-type relationship at a shear rate of 10, 50, 100 s-1 IR analysis was done to know the influence of functional groups on rheological properties of purees. Consistency index (K) of puree increases with increase in TSS content but at a fixed TSS, there is a decrease in K with an increase in temperatures but the opposite was observed for flow behavior index (n). Puree showed a shear thinning behavior with an increment in temperature level and puree having 5 °Brix (8.37) has higher activation energy (kJ.mol-1) than 3 °Brix (6.32).  

An Influence of a Binder System to the Rheological Behavior of the SS316L Metal Injection Molding (MIM) Feedstock

2011 ◽  
Vol 264-265 ◽  
pp. 554-558 ◽  
Author(s):  
Khairur Rijal Jamaludin ◽  
Norhamidi Muhamad ◽  
Hooman Abolhasani ◽  
Hadi Murthadha ◽  
Mohd Nizam Ab. Rahman
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Injection Molding ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Metal Injection Molding ◽  
Binder System ◽  
Flow Behavior Index ◽  
Injection Molded

The influence of a binder system to the rheological behavior of a Metal Injection Molding (MIM) feedstock is presented in the paper. The binder systems used are: a) PEG & PMMA b) Palm stearin & LLDPE and, c) Tapioca starch & LLDPE. The viscosity and shear rate of the feedstocks were measured at various range of temperature and shear rate across the L/D = 10 capillary rheometer. The flow behavior index, n and activation energy, E of each feedstock were measured to show its significance as MIM feedstock. Generally, the result indicates all feedstock exhibits a shear thinning behavior and the binders are suitable as MIM binder. Additionally, the present paper has discovered that the binder system does not have much influence to the activation energy. In order to show the relevance of the rheological behavior to the actual injection molding performance, green parts has been injection molded and the result shows an agreement with the rheological behavior result.

Rheological Behavior of Yttria Stabilized Zirconia (YSZ) Feedstock for Ceramic Injection Moulding (CIM) Process

2017 ◽  
Vol 882 ◽  
pp. 119-123
Author(s):  
Mahfuzah Zainudin ◽  
Muhammad Hussain Ismail
Keyword(s):  
Rheological Behavior ◽  
Injection Moulding ◽  
Flow Behavior ◽  
Palm Stearin ◽  
Stabilized Zirconia ◽  
Flow Behavior Index ◽  
Green Strength ◽  
Ceramic Injection Moulding ◽  
Behavior Index

The characterization of CIM feedstock consisting 58, 59, 60vol% of YSZ powder with binder system comprising a palm stearin (PS) and low density polyethylene (LDPE) were studied. The effects of powder loading and temperature (°C) on the rheological behavior of the YSZ were investigated by using Rosand RH2000 Capillary Rheometer. The results showed all the feedstock achieved desirable injection moulding characteristics such as pseudoplastic behavior, flow behavior index (n) less than 1 and low activation energy (E). The rectangular parts were successfully injected moulded at optimum temperature of 170°C with the highest green strength was 12.7 N, obtained from 60 vol% powder loading which correspond to greater density and low porosity of the samples.

Development of a Starch-Based Binder in Metal Injection Molding

2009 ◽  
Vol 83-86 ◽  
pp. 24-30 ◽  
Author(s):  
Norhamidi Muhamad ◽  
Hooman Abolhasani
Keyword(s):  
Injection Molding ◽  
Rheological Behavior ◽  
Flow Behavior ◽  
Steel Powder ◽  
Metal Injection Molding ◽  
Linear Low Density Polyethylene ◽  
Flow Behavior Index ◽  
Different Temperatures ◽  
316 L Stainless Steel ◽  
Behavior Index

A new starch-based binder as a natural polymer has been developed for metal injection molding (MIM). In this study tapioca starch which is cheap and readily available in Malaysia has been used as a binder which composed of starch, glycerol, linear low density polyethylene (LLDPE), citric acid and stearic acid. This developed binder system was mixed with 316 L stainless steel powder to prepare the feedstock at three different of powder loadings of 56, 57 and 58% vol. The rheological behavior of the binder and feedstock were evaluated at different temperatures using a capillary rheometer. The rheological behavior of binder shows less than 10 Pa s and the flow behavior index of the feedstocks were determined to less than 1, which indicates the flow characteristic is pseudo-plastic which is suitable for MIM process. Finally, among these three feedstocks, the feedstock of 57% vol. powder loading was selected and its viscosity values within expected shear rate range are less than 1000 Pa s.

scholarly journals Effect of grasshopper (Sphenarium purpurascens Charpentier) paste addition on rheological behavior of Mole Poblano

2021 ◽  
Author(s):  
Eliza Guadalupe Arcos-Estrada ◽  
Mayra Díaz-Ramírez ◽  
Judith Jiménez-Guzmán ◽  
Erika Berenice León-Espinosa ◽  
Mariano García-Garibay ◽  
...  
Keyword(s):  
Rheological Behavior ◽  
Apparent Viscosity ◽  
Design Methodology ◽  
Water Retention ◽  
Flow Behavior ◽  
Rheological Parameters ◽  
Flow Behavior Index ◽  
Emulsifying Capacity ◽  
Behavior Index

Objective: Analyze the effect of grasshopper (Sphenarium purpurascens Charpentier) paste addition on the rheological behavior of Mole Poblano (MP) and its relation with the technological properties of the grasshopper paste. Design/methodology/approach: The addition of grasshopper paste was done at different proportions as follows: T0= 0% of grasshopper paste (GP) and 100% of mole Poblano (MP); T10=10% GP and 90% MP; T15=15% GP and 85% MP, T20=20% GP and 80% MP, T25=25% GP and 75 % MP, T30=30% GP and 70% MP. Water retention and emulsifying capacity of grasshopper paste were evaluated. Density, kinematic and apparent viscosity, and rheological behavior were analyzed at 25ºC; rheological parameters (consistency index (k) and flow behavior index (n)) were calculated by performing a regression analysis to adjust the graphs to a power-law model. Findings/conclusion: Grasshopper paste had higher emulsifying capability than water retention capability.  Apparent viscosity of all formulations decreased as shear rate increased, so all mixtures of GP and MP demonstrated No-Newtonian behavior and pseudoplastic performance. Index consistency increased as GP content increased, these results are related with protein content because GP had a good emulsifying capability. Limitations on study/implications: More studies about the characterization of the proteins of GP and their interaction with other components are required.

Effects of Greek Pomegranate Extracts in the Antioxidant Properties and Storage Stability of Kefir

2019 ◽  
Vol 15 (4) ◽  
pp. 437-441 ◽  
Author(s):  
Vasiliki Lagouri ◽  
Georgia Dimitreli ◽  
Aikatarini Kouvatsi
Keyword(s):  
Antioxidant Activity ◽  
Dairy Products ◽  
Storage Time ◽  
Storage Stability ◽  
Flow Behavior ◽  
Antioxidant Properties ◽  
Flow Behavior Index ◽  
Ph Values ◽  
Dpph Activity ◽  
Behavior Index

Background: Oxidation reactions are known to shorten the shelf life and cause damage to foods rich in fat, such as dairy products. One way to limit oxidation and increase the shelf life of fermented dairy products is to use natural antioxidants. The aim of this study was to examine the effect of adding pomegranate extracts in the antioxidant properties, rheological characteristics and the storage stability of the fermented product of kefir. Methods: The Pomegranate Juice (PGJ) and Peel Extracts (PGPE) (5%, 10% w/v) were added to kefir and the antioxidant properties were evaluated by using the methods of radical scavenging activity (DPPH) and Ferric Reducing Antioxidant Power Activity (FRAP). Spectrophotometric and instrumental methods were used to determine the Total Phenols (TPs), pH values, viscosity and flow behavioral index values of enriched with pomegranate kefir samples. The same properties were tested when kefir samples stored at 4°C for 7, 14, 21 and 28 days. Results: The addition of PGJ and PGPE results in an increase in the antioxidant activity (DPPH, FRAP) and total phenol content (TPs) of kefir samples. Increasing the concentration of the added PGJ and PGPE, results in an increase in the TP content and the DPPH activity of kefir. As far as the storage time is concerned, the results showed an increase in the amount of TP at 7th day and a reduction in the DPPH activity in the 14th day of storage. In contrary to the DPPH method, the increase in storage time has resulted in a reduction in antioxidant activity by the FRAP method. The addition of PGJ and PGPE in kefir results in a decrease in pH values while the pH of kefir samples increased during storage at 4°C for 28 days. The addition of PGJ and PGPE to kefir samples results to a decrease in viscosity and an increase in the flow behavior index. Increasing storage time results in increased flow behavior index of kefir samples. Conclusion: The addition of PGJ and PGPE increased the antioxidant activity and total phenols of the kefir product and preserved its properties during the total storage time of 28 days at 4°C.

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