Determination of the Compressive Material Properties of the Supraspinatus Tendon

2000 ◽  
Vol 123 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Mark E. Zobitz ◽  
Zong-Ping Luo ◽  
Kai-Nan An
Keyword(s):  
Material Properties ◽  
Three Dimensional ◽  
Supraspinatus Tendon ◽  
Hyperelastic Material ◽  
Compressive Properties ◽  
Energy Potential ◽  
The Matrix ◽  
Three Dimensional Models ◽  
Thickness Measurements

A methodology was developed for determining the compressive properties of the supraspinatus tendon, based on finite element principles. Simplified three-dimensional models were created based on anatomical thickness measurements of unloaded supraspinatus tendons over 15 points. The tendon material was characterized as a composite structure of longitudinally arranged collagen fibers within an extrafibrillar matrix. The matrix was formulated as a hyperelastic material described by the Ogden form of the strain energy potential. The hyperelastic material parameters were parametrically manipulated until the analytical load-displacement results were similar to the results obtained from indentation testing. In the geometrically averaged tendon, the average ratio of experimental to theoretical maximum indentation displacement was 1.00 (SD: 0.01). The average normalization of residuals was 2.1g (SD: 0.9g). Therefore, the compressive material properties of the supraspinatus tendon extrafibrillar matrix were adequately derived with a first-order hyperelastic formulation. The initial compressive elastic modulus ranged from 0.024 to 0.090 MPa over the tendon surface and increased nonlinearly with additional compression. Using these material properties, the stresses induced during acromional impingement can be analyzed.

Synthesis of Three-Dimensional Models from Drawings Based on Spectral Graph Theory

2015 ◽  
Vol 756 ◽  
pp. 598-603 ◽  
Author(s):  
Aleksey Zakharov ◽  
Arkady Zhiznyakov
Keyword(s):  
Graph Theory ◽  
Three Dimensional ◽  
Spectral Graph Theory ◽  
Boundary Representation ◽  
Three Dimensional Model ◽  
Three Dimensional Objects ◽  
Spectral Graph ◽  
Dimensional Models ◽  
Three Dimensional Models

Task of automatic reconstruction of three-dimensional objects by drawing views presented. The algorithm based on a boundary representation of three-dimensional models. The algorithm consists of the following steps: automatic separation of the drawing per the views, determination of three-dimensional coordinates of vertices, definition and marking of wire model primitives, reconstruction of model faces and model elements. The fundamental concept of the algorithm is to find the structural elements of three-dimensional model with usage of pre-specified patterns. The templates are described by means of matrices. Matching algorithm uses spectral graph theory. Reconstruction results are presented.

scholarly journals Determination of technological parameters and tool for flanging holes from sheet blanks

2020 ◽  
Vol 164 ◽  
pp. 14019
Author(s):  
Khaidar Kaderov ◽  
Sergey Kireev ◽  
Marina Korchagina ◽  
Aleksey Lebedev
Keyword(s):  
Technological Development ◽  
Three Dimensional ◽  
Hole Diameter ◽  
Simultaneous Increase ◽  
Technological Parameters ◽  
Cad System ◽  
Dimensional Models ◽  
Three Dimensional Models ◽  
The Given

In the article the parameters of shaping operations of internal axisymmetric cylindrical flanging are considered. The article is written to improve the quality and speed of flanging round holes development from sheet blanks and tooling construction by increasing the accuracy of hole diameter calculation for flanging in the automated mode of building three-dimensional models of workpiece and a flanged product. Given formulas increase the accuracy of hole diameter calculation for flanging, taking into account the deformed condition of the sheet blank. The accuracy of the hole diameter calculation for flanging according to the given formulas is determined by comparing the mass of the workpiece with the mass of the flanged part. CAD system algorithm for automated construction of the flanged parts sketch and determination of technological parameters is implemented. The parameterized scheme of a typical construction of a flanging stamp is presented. The constructed schemes allow making changes in their parameters and providing automatic representation of calculation results and also their correct graphic interpretation. Discussion of the article results allows drawing conclusions about correctness of the given mathematical model and its applicability for the automated construction of three-dimensional models of the flanged details that will allow simplifying technological development and constructed documentation with simultaneous increase of their accuracy and reducing costs of production preparation.

scholarly journals DETERMINATION OF PIROCARBON MATRIX CHARACTERISTICS IN CARBON/CARBON COMPOSITES

2021 ◽  
Vol 64 (5) ◽  
pp. 44-49
Author(s):  
Maria V. Papkova ◽  
Sergei V. Tashchilov ◽  
Ilya V. Magnitsky ◽  
Alexander E. Dvoretsky
Keyword(s):  
Structural Characteristics ◽  
Three Dimensional ◽  
Carbon Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Extinction Angle ◽  
Parallel Layer ◽  
The Matrix ◽  
Average Size

One of the methods of carbon/carbon composites (C/C composites) production is the deposition of a pyrocarbon (pyC) matrix in a porous preform. The investigation of the pyC matrix characteristics is based on the optical anisotropy with determination of the extinction angle Ae and X-ray diffraction determination of the interplanar spacing d002, crystallite size in the direction of stacking of graphite layers Lc and average size of graphite planes parallel layer in crystallites La. In this study, three previously produced by the thermal gradient method with different parameters specimens of C/C composites were investigated by optical microscopy and X-ray diffraction methods. The studied specimens have a different type of a texture and different structural characteristics of the pyC matrix. Extinction angle Ae for specimen 1, specimen 2 and 3 was 5°, 19° and 41°, respectively. The range of the extinction angle for the pyC matrix is wider than that presented in literature. And according to the classification of pyC the matrix of specimen 1, specimen 2 and 3 is dark laminar pyC, rough laminar pyC and highly textured pyC. For specimen 2 the largest d002 equal to 0.3476 nm was observed. The lowest degree of three-dimensional ordering relative other specimens was for the specimen 2 with rough laminar pyC matrix. The highest degree of three-dimensional ordering was for the specimen 3 with highly textured pyC matrix. However, there is no direct relationship between the textural and structural characteristics of the pyC matrix. Therefore, the study of the pyC matrix should be based on optical and X-ray diffraction methods.

scholarly journals Determination of the hyperelastic material behavior of hydrogel specimens for expandable lens implants

2019 ◽  
Vol 5 (1) ◽  
pp. 351
Author(s):  
Heiner Martin ◽  
Olga Sahmel ◽  
Thomas Eickner ◽  
Niels Grabow ◽  
Christine Kreiner ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Material Properties ◽  
Element Model ◽  
Material Behavior ◽  
Hyperelastic Material ◽  
Human Lens ◽  
Experimental Investigations

Abstract Theoretical and experimental investigations were carried out for development of human lens implants made from hydrogel material. The material properties were measured and implemented in a Finite element model. Though the material is still too stiff for accommodative lenses, the theoretical and experimental foundations for the implant development were established.

Molecular Docking Supplements an In vitro Determination of the Leading CYP Isoform for Arylpiperazine Derivatives

2019 ◽  
Vol 22 (6) ◽  
pp. 370-378 ◽  
Author(s):  
Szymon Ulenberg ◽  
Tomasz Bączek ◽  
Joanna Zieliñska ◽  
Mariusz Belka ◽  
Marek Król ◽  
...  
Keyword(s):  
Molecular Docking ◽  
In Silico ◽  
Three Dimensional ◽  
In Vitro Studies ◽  
Three Dimensional Model ◽  
Promising Tool ◽  
Three Dimensional Models ◽  
Early Drug

Background: Molecular docking has often been used before to calculate in silico affinity of drugs towards their molecular target, but not to estimate leading CYP isoform responsible for metabolism of studied compounds. Objective: The aim of this study is to present molecular docking as a valid alternative for costly in vitro studies resulting in estimation of leading CYP isoform. Method: In vitro part was based on incubations of studied compounds with isolated CYP3A4 isoform followed by LC-MS analysis. The in silico stage consisted of docking three-dimensional models of the studied compounds with a three-dimensional model of the leading metabolizing isoform (CYP3A4), which was designated during the in vitro part of the study. XenoSite P450 metabolism prediction was also used to predict sites of metabolism and calculate probability values. Results: The calculated affinities showed a clear similarity when the in vitro results were compared with the calculated in silico affinity values. XenoSite CYP3A4 metabolism probability values also confirm significant participation of CYP3A4 in metabolism of studied compounds. Conclusion: Both molecular docking and XenoSite P450 metabolism prediction provide data that stands in agreement with in vitro studies, granting a more detailed spectrum on predicting CYP3A4 metabolism, and presenting molecular docking as a promising tool to cut costs and increase effectiveness in early drug development stages.

Analytical Derivation of Cosserat Moduli via Homogenization of Heterogeneous Elastic Materials

2006 ◽  
Vol 74 (4) ◽  
pp. 741-753 ◽  
Author(s):  
D. Bigoni ◽  
W. J. Drugan
Keyword(s):  
Three Dimensional ◽  
Heterogeneous Material ◽  
Material Response ◽  
Spherical Inclusions ◽  
The Matrix ◽  
Cylindrical Inclusions ◽  
Dilute Suspension ◽  
Experimental Findings ◽  
Do So

Why do experiments detect Cosserat-elastic effects for porous, but not for stiff-particle-reinforced, materials? Does homogenization of a heterogeneous Cauchy-elastic material lead to micropolar (Cosserat) effects, and if so, is this true for every type of heterogeneity? Can homogenization determine micropolar elastic constants? If so, is the homogeneous (effective) Cosserat material determined in this way a more accurate representation of composite material response than the usual effective Cauchy material? Direct answers to these questions are provided in this paper for both two- (2D) and three-dimensional (3D) deformations, wherein we derive closed-form formulae for Cosserat moduli via homogenization of a dilute suspension of elastic spherical inclusions in 3D (and circular cylindrical inclusions in 2D) embedded in an isotropic elastic matrix. It is shown that the characteristic length for a homogeneous Cosserat material that best mimics the heterogeneous Cauchy material can be derived (resulting in surprisingly simple formulae) when the inclusions are less stiff than the matrix, but when these are equal to or stiffer than the matrix, Cosserat effects are shown to be excluded. These analytical results explain published experimental findings, correct, resolve and extend prior contradictory theoretical (mainly numerical and limited to two-dimensional deformations) investigations, and provide both a general methodology and specific results for determination of simple higher-order homogeneous effective materials that more accurately represent heterogeneous material response under general loading conditions. In particular, it is shown that no standard (Cauchy) homogenized material can accurately represent the response of a heterogeneous material subjected to a uniform plus linearly varying applied traction, while a homogenized Cosserat material can do so (when inclusions are less stiff than the matrix).

Thermal Analysis of Dedicated Computer Based on ANSYS

2011 ◽  
Vol 697-698 ◽  
pp. 277-281
Author(s):  
Y.R. Zhang ◽  
L. Gao ◽  
S.J. Li ◽  
H.X. Bi
Keyword(s):  
Thermal Analysis ◽  
Material Properties ◽  
Theoretical Basis ◽  
Three Dimensional ◽  
Test Results ◽  
Post Processing ◽  
Ansys Software ◽  
Computer Based ◽  
Three Dimensional Models ◽  
Setting Parameters

After creating the three-dimensional models of dedicated computer, models can be smoothly put into ANSYS through interface between Pro/E and ANSYS. By selecting the grid cells, setting parameters of material properties, dividing grids, applying load and boundary conditions and post-processing, the temperature contours of the whole case and its key components are got. Compared with the test results, it was verified that the feasibility and rationality of carrying out thermal simulation by ANSYS software, providing a theoretical basis for the designers to optimize dedicated computer case.

scholarly journals É possível ensinar a genética para alunos cegos?

2017 ◽  
Vol 8 (16) ◽  
Author(s):  
Mauro Luiz Da Hora Faria ◽  
Janilda Pacheco da Costa ◽  
Cristina Delou ◽  
Gerlinde Agate Platais Brasil Teixeira
Keyword(s):  
High School ◽  
Science Education ◽  
High School Teachers ◽  
Three Dimensional ◽  
Special Educational Needs ◽  
School Teachers ◽  
Dna Molecule ◽  
The Matrix ◽  
Three Dimensional Models ◽  
Blind Students

O uso de modelos tridimensionais é uma estratégia que facilita ensinar temas considerados difíceis para muitos professores no ensino médio, mesmo para classes que não têm alunos com necessidades educacionais especiais. Tivemos como objetivo, portanto, desenvolver um modelo tátil que auxiliasse na compreensão da estrutura do DNA e de sua replicação. Para tanto, adaptamos os passos descritos por Miotto para a construção de modelos táteis. O resultado foi a construção da matriz e das estruturas básicas da molécula de DNA, em papelão coberto com diferentes texturas. As placas de acetato em alto relevo foram preparadas após a aprovação por um aluno cego, que informou que a escala e as texturas escolhidas possibilitaram a identificação da estrutura como um todo e de suas partes, que foram testadas e aprovadas por alunos cegos na sala de recursos de uma Escola Pública Estadual.Palavras-chave: Construtivismo. Linguagem da ciência e da sala de aula. Ensino de ciências. Educação especial. Genética.Teaching genetics to blind-students – is it possible?AbstractThe use of three-dimensional models is a strategy that facilitates teaching contents considered difficult for many high school teachers even in classes that do not have students with special educational needs. Our objective was to develop a tactile model that helps the understanding of the DNA structure and its replication. To achieve this, we adapted the steps proposed by Miotto for the production of tactile models. As a result, we constructed the matrix of the basic structures of the DNA molecule in cardboard covered with different textures. After approval by a blind student, who reported that the scale and textures chosen allowed identification of the structure as a whole and its parts, we prepared the high relief acetate plates. These were tested and approved by blind students in the “resource class” of a State Public School.Keywords: Constructivism. Science and classrooms language. Science education. Special education. Genetics.

scholarly journals Sub-tomogram averaging in RELION

2015 ◽  
Author(s):  
Tanmay A.M. Bharat ◽  
Sjors H.W. Scheres
Keyword(s):  
Single Particle ◽  
De Novo ◽  
Three Dimensional ◽  
Particle Analysis ◽  
Single Particle Analysis ◽  
Contrast Transfer Function ◽  
Three Dimensional Models ◽  
Initial Classification

Electron cryo-tomography (cryo-ET) and sub-tomogram averaging allow structure determination of macromolecules in situ, and are gaining in popularity for initial model generation for single- particle analysis. We describe herein, a protocol for sub-tomogram averaging from cryo-ET data using the RELION software. We describe how to calculate newly developed three-dimensional models for the contrast transfer function and the missing wedge of each sub-tomogram, and how to use these models for regularized-likelihood refinement. This approach has been implemented in the existing workflow for single-particle analysis, so that users may conveniently tap into existing capabilities of the RELION software. As example applications, we present analyses of purified hepatitis B capsid particles and S. cerevisiae 80S ribosomes. In both cases, we show that following initial classification, sub-tomogram averaging in RELION allows de novo generation of initial models, and provides high-resolution maps where secondary structure elements are resolved.

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