Determination of material models for arterial walls from uniaxial extension tests and histological structure

Abstract The determination of the material coefficients for Ogden, Mooney-Rivlin, Peng, and Peng-Landel material models using simple ASTM D 412 tensile data is shown to be a manageable task. The application of the various material models are shown to be subject to the type and level of deformation expected, with Ogden showing the best correlation with experimental data over a large strain range for the three types of strain investigated. At low strains, all of the models showed reasonable correlation.

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Changes in Liver Parenchyma of Green Frogs (Pelophylax Esculentus Complex) Under Conditions of Anthropogenic Pollution and Their Use in Monitoring of Water Bodies

Vestnik Zoologii ◽

10.1515/vzoo-2015-0053 ◽

2015 ◽

Vol 49 (5) ◽

pp. 453-458

Author(s):

N. M. Akulenko

Keyword(s):

Biological Effects ◽

Fibrous Tissue ◽

Anthropogenic Pollution ◽

Normal Liver ◽

Liver Parenchyma ◽

Histological Structure ◽

Liver Structure ◽

Pelophylax Esculentus

Determination of the total biological effects of anthropogenic water pollution remains an important issue. Our long-term studies have shown that numerous alterations occur in the frog liver histological structure under pressure of anthropogenic pollution factor. Th e leukocyte infiltration, fat dystrophy, protein dystrophy and necrosis are well known on the mammal liver. Also we first described the rebuilding in the normal liver structure and the depletation of the fibrous tissue which are characteristic for the amphibians. Quantitative analysis of these alterations can identify significant differences in the pattern of pathological changes in the liver of the green frogs, which pick up in anthropogenically contaminated landscapes and in the clear ponds. Th is method allows quantifying the degree of biological effect of pollution.

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Some Considerations about Twin Zygosity and Concordance Determination in Cancer Research

Acta geneticae medicae et gemellologiae ◽

10.1017/s1120962300025038 ◽

1970 ◽

Vol 19 (1-2) ◽

pp. 65-65

Author(s):

R. P. Martynova

Keyword(s):

Cancer Research ◽

Malignant Neoplasm ◽

Histological Structure ◽

Concordance Index ◽

Human Beings ◽

Objective Criterion ◽

Hereditary Factors ◽

Questionnaire Method ◽

Image Position

Studies on cancer in man and pure strain animals have shown that the malignant neoplasm, both in animals and in human beings, is not a single, genetically homogeneous disease: it consists of a lot of forms differing in localization, histological structure and etiopathogenesis. This circumstance is not always taken into account by the investigators in cancer research by the twin method, and especially in the determination of within-pair concordance/discordance, which is often a source of misunderstandings and faulty conclusions.In order to establish a more objective criterion for estimating the real twin concordance in the studies of such diseases as cancer, we have worked out a quantitative index called Concordance Index:where: CI = Concordance Index %; a = number of twin pairs, MZ or DZ, which are fully concordant for the principal features; b = number of partially concordant twin pairs; n = total number of twin pairs, MZ or DZ.The accuracy of twin zygosity determination acquires a particular importance in cases of low penetrance of the disease. In such cases, even a minor inaccuracy in the zygosity diagnosis may considerably influence the twins' CI, and always in the same direction: any mistake in the determination of twin zygosity always leads to an artificial diminution of the role of hereditary factors. Therefore, we consider that the questionnaire method of twin zygosity determination, as well as any other insufficiently objective method, should not be used in the genetic studies on cancer.

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Determination of the parameters of the Prony series in hyper-viscoelastic material models using the finite element method

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2011.05.057 ◽

2012 ◽

Vol 35 ◽

pp. 791-797 ◽

Cited By ~ 59

Author(s):

Mir Hamid Reza Ghoreishy

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Viscoelastic Material ◽

Prony Series ◽

The Finite Element Method ◽

Material Models ◽

Element Method

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Determination of the Constants of Material Models Using Inverse Taylor Test

Experimental Techniques ◽

10.1007/s40799-016-0062-4 ◽

2016 ◽

Vol 40 (2) ◽

pp. 609-620 ◽

Cited By ~ 1

Author(s):

G. H. Majzoobi ◽

P. Kazemi ◽

M. K. Pipelzadeh

Keyword(s):

Material Models ◽

Taylor Test

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Determination of the Constants of Zerilli-Armstrong Constitutive Relation Using Genetic Algorithm

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.264-265.862 ◽

2011 ◽

Vol 264-265 ◽

pp. 862-870

Author(s):

G.H. Majzoobi ◽

S. Faraj Zadeh Khosroshahi ◽

H. Beik Mohammadloo

Keyword(s):

Genetic Algorithm ◽

High Strain ◽

Optimization Technique ◽

Strain Curve ◽

Strain Rates ◽

Stress Strain Curve ◽

Stress Strain ◽

Material Models ◽

The Difference

Identification of the constants of material models is always a concern. In the present work, a combined experimental, numerical and optimization technique is employed to determine the constants of Zerilli-Armstrong model. The experiments are conducted on a compressive Hopkinson bar, the simulations are performed using finite element method and optimization is carried out using genetic algorithm. In the method adopted here, there is no need for experimental stress-strain curve which is always accompanied by restricting phenomenon such as necking in tension and bulging in compression. Instead of stress-strain curve, the difference between the post-deformation profiles of specimens obtained from experiment and the numerical simulations is adopted as the objective function for optimization purposes. The results suggest that the approach introduced in this work can substitute costly instrumentations normally needed for obtaining stress-strain curves at high strain rates and elevated temperature.

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