scholarly journals Changes in the force relaxation of Edam cheese during ripening

2010 ◽  
Vol 58 (5) ◽  
pp. 271-280
Author(s):  
Šárka Nedomová
Keyword(s):  
Loading Rate ◽  
Viscoelastic Body ◽  
Rheological Behaviour ◽  
Maxwell Model ◽  
Mechanical Tests ◽  
Fat Content ◽  
Stress Relaxation Test ◽  
Force Relaxation ◽  
Linear Viscoelastic ◽  
Semi Empirical

The present study was performed to determine the influence of fat content and ripening time on changes in the viscoelastic properties and, separately, in the viscous and elastic properties of Edam cheese, based namely on the results of a stress–relaxation test. In order to obtain some more detail inside on the cheese rheological behaviour a limited number of the mechanical tests under compression has been performed. The significant effect of the loading rate has been demonstrated. The main aim was to describe the experimental results in terms of the semi-empirical Maxwell model, which describe the rheological properties of cheese during ripening. Results suggest that the tested cheeses behave like linear viscoelastic body. The fat content has no influence on the elasticity as well the viscosity of the cheese during its ripening.

scholarly journals Texture and rheological evaluation of aerated confectionery

2020 ◽  
Vol 31 (1) ◽  
pp. 60-65
Author(s):  
Sergiu Pădureţ ◽  
Raluca-Olimpia Zimbru ◽  
Sonia Amariei
Keyword(s):  
Relaxation Time ◽  
Elasticity Modulus ◽  
Pearson Correlation ◽  
Maxwell Model ◽  
Fat Content ◽  
Rheological Parameter ◽  
Stress Relaxation Test ◽  
Equilibrium Stress ◽  
Texture Parameters ◽  
Relaxation Curves

AbstractConfectionery industry represents a field that uses a large number of ingredients and techniques to develop unique sweet products. To produce aerated confectionery samples two different procedures were used to incorporate the ingredients in the beating vegetable or dairy cream. The objective of this research was to determine the texture parameters and the viscoelastic properties of aerated confections using compression stress-relaxation test and applying a modified Maxwell model. The highest fat content was presented by dairy cream aerated samples (20.04-20.25%), while the samples based on vegetable cream displayed a lower fat content. By applying the modified Maxwell mechanical model to the relaxation curves the equilibrium stress, σe, relaxation time, λrel, viscosity, η, and modulus of elasticity, G0, were determined. The aerated samples’ viscosity was greater than 137.96 kPa·s and less than 451.793 kPa·s; furthermore, Pearson correlation showed that density influences positively this rheological parameter (r = 0.955*). Fixing air into the product structure causes a decrease in density (0.388-0.788 g/cm3), leading to a lower equilibrium stress, a lower elasticity modulus and also a decrease of viscosity and relaxation time.

Investigation of the Staging of Damage Accumulation in Polymer Composite Materials during Bending and Tensile Tests

2021 ◽  
Vol 887 ◽  
pp. 116-122
Author(s):  
A.A. Bryansky ◽  
O.V. Bashkov ◽  
Daria P. Malysheva ◽  
Denis B. Solovev
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Polymer Composite ◽  
Loading Rate ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Rate Effect ◽  
Polymer Composite Materials ◽  
Static Tension ◽  
Point Bend

The paper presents the results of the study of registered acoustic emission (AE) parameters during static deformation and damaging of polymer composite materials (PCM). Mechanical tests were done by a static tension and a static three-point bend, accompanied by an acoustic emission method. The assessment of the loading rate effect on defects formation processes was done by additional static tension test at rate equal half of recommended by the standard and static three-point bend test at rate ten times lower than that calculated by the standard. Clustering by frequency components of the recorded AE signals with a self-organizing Kohonen map was performed. The characteristics of the types of PCM structure damage by the centroids of the obtained clusters are given. Based on the clusters accumulation during mechanical tests, the stages of damage formation for static tension and static three-point bend, the loading rate effect on the process of damage formation are described.

Rheology of colloids

Surfactants ◽  
2019 ◽  
pp. 400-424
Author(s):  
Bob Aveyard
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
Shear Thickening ◽  
Rheological Behaviour ◽  
Maxwell Model ◽  
Colloidal Dispersions ◽  
Shear Strain Rate ◽  
Plastic Behaviour ◽  
Shear Thickening Fluids ◽  
External Forces

Lyophobic colloidal dispersions, aggregated surfactant systems, and polymer solutions, as well as foams and emulsions, can all be deformed by weak external forces; rheology is the study of deformation and flow of materials. Various rheological quantities arising from the response of a material to shear are defined. For liquids the stress, τ‎, applied is related to the rate of deformation, that is, the shear strain rate, γ̇. For Newtonian fluids τ‎ and γ̇ are linearly related and τ‎ / γ̇ is the viscosity, η‎. Other nonlinear relationships correspond to shear thinning and shear thickening fluids and to plastic behaviour in which there is a yield stress. Viscoelastic systems exhibit both viscous and elastic properties; such behaviour is often treated using the simple Maxwell model. Some illustrative experimentally observed rheological behaviour is presented.

scholarly journals Influence of cheese ripening on the viscoelastic behaviour of edam cheese

2013 ◽  
Vol 19 (No. 1) ◽  
pp. 1-7 ◽  
Author(s):  
J. Buchar ◽  
I. Kubiš ◽  
S. Gajdůšek ◽  
I. Křivánek
Keyword(s):  
Viscoelastic Properties ◽  
Rheological Model ◽  
Deformation Behaviour ◽  
Viscoelastic Body ◽  
Original Method ◽  
Cheese Ripening ◽  
Linear Viscoelastic ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Pressure Bar

The paper deals with the study of the effect of cheese ripening on parameters of a rheological model of cheese mechanical behaviour. The Edam cheese has been tested by the method of the Hopkinson Split Pressure Bar. The original method of the evaluation of viscoelastic properties has been used. The rheological model of the three element linear viscoelastic body, so called “standard linear solid” has been used. This model successfully describes the experimentally observed deformation behaviour of cheese specimens. The effect of the time of cheese ripening on the parameters of the rheological model has been demonstrated.

The Effect of Refrigerated Storage on the Rheological Properties of Three Commercial Mozzarella Cheeses

2008 ◽  
Vol 4 (4) ◽  
Author(s):  
Edward B Muliawan ◽  
Savvas G Hatzikiriakos
Keyword(s):  
Rheological Properties ◽  
Viscoelastic Properties ◽  
Elevated Temperatures ◽  
Maxwell Model ◽  
Model Parameters ◽  
Refrigerated Storage ◽  
Mozzarella Cheese ◽  
Relaxation Dynamics ◽  
Generalized Maxwell Model ◽  
Linear Viscoelastic

The linear and non-linear viscoelastic properties and the effect of refrigerated storage on the rheological properties of three commercial mozzarella cheeses was studied. The linearity of the rheological behavior of mozzarella cheese increases with temperature because of the ability for the cheese to flow easier at higher temperatures as well as the lack of yield stress at elevated temperatures. The generalized Maxwell model parameters obtained from the linear viscoelastic data were found to describe the linear relaxation dynamics of the mozzarella cheese satisfactorily. It is also shown that the damping function of mozzarella cheese, which is a measure of the degree of non-linearity, can be described by a generalized Zapas model. Although, the different commercial mozzarella cheeses do not exhibit linear viscoelastic differences at room temperature, they do show significant differences at 60°C. The effect of refrigerated storage on the linear viscoelastic properties is brand-dependent and indicates structural differences among cheese samples. Finally it is shown that the dynamic moduli decrease with longer refrigerated storage due to proteolysis activities and/or weakening of the casein matrix.

An Approach to Characterize Nonlinear Viscoelastic Material Behavior Using Dynamic Mechanical Tests and Analyses

1999 ◽  
Vol 66 (4) ◽  
pp. 872-878 ◽  
Author(s):  
H. J. Golden ◽  
T. W. Strganac ◽  
R. A. Schapery
Keyword(s):  
Viscoelastic Model ◽  
Dynamic Test ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Material Behavior ◽  
Dynamic Mechanical ◽  
Nonlinear Characterization ◽  
Nonlinear Viscoelastic ◽  
Linear Viscoelastic ◽  
Nonlinear Viscoelastic Model

Linear viscoelastic properties may be rapidly identified using dynamic mechanical analysis methods, yet these traditional methods do not properly identify nonlinear viscoelastic response. Herein, dynamic mechanical methodologies are extended to provide an approach for nonlinear characterization. The proposed method is based on Schapery's nonlinear viscoelastic model extended to dynamic mechanical theory. The oscillatory loading during a dynamic test is addressed within the nonlinear viscoelastic model. An experimental protocol is established. Analyses and experiments are performed for the characterization of thin-film polyethylene to validate the approach.

An efficient seismic modeling in viscoelastic isotropic media

Geophysics ◽  
2015 ◽  
Vol 80 (1) ◽  
pp. T63-T81 ◽  
Author(s):  
Renhu Yang ◽  
Weijian Mao ◽  
Xu Chang
Keyword(s):  
Seismic Waves ◽  
Linear Equations ◽  
Viscoelastic Body ◽  
Elastic Stiffness ◽  
Momentum Conservation ◽  
Stiffness Matrices ◽  
Isotropic Media ◽  
Linear Viscoelastic ◽  
Standard Linear ◽  
Viscoelastic Modeling

Energy is absorbed and attenuated when seismic waves propagate in real earth media. Hence, the viscoelastic medium needs to be considered. There are many ways to construct the viscoelastic body, in which the generalized standard linear viscoelastic body is the most representative one. For viscoelastic wave propagation and imaging, it is very important to obtain a compact and efficient viscoelastic equation. Because of this, we derived a set of simplified viscoelastic equations in isotropic media on the basis of the standard linear solid body and the constitutive relation for a linear viscoelastic isotropic solid. The simplified equations were composed of the linear equations of momentum conservation, the stress-strain relations, and the memory variable equations. During the derivation of the equations, the Lamé differentiation matrix, which has a similar form to the stiffness matrix and indicates the relations between viscoelastic and elastic stiffness matrices, was introduced to simplify the memory variable equations. Analogous to the elastic equations, the simplified equations have symmetrically compact forms and are very useful for efficient viscoelastic modeling, migration, and inversion. Applied to a 2D simple model and the 2D SEG/EAGE salt model, the results show that our simplified equations are more efficient in computation than Carcione’s equations.

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