scholarly journals Origins of halogen effects in bioorthogonal sydnone cycloadditions

2018 ◽  
Vol 54 (40) ◽  
pp. 5082-5085 ◽  
Author(s):  
Huimin Tao ◽  
Fang Liu ◽  
Ruxin Zeng ◽  
Zhuzhou Shao ◽  
Lufeng Zou ◽  
...  
Keyword(s):  
Distortion Energy ◽  
Blue Arrow

In bioorthogonal sydnone cycloadditions, the fluorine substituent dramatically increases the reactivity of sydnone mainly by lowering its distortion energy (see blue arrow).

scholarly journals F.E.M. Stress-Investigation of Scolios Apex

2018 ◽  
Vol 12 (1) ◽  
pp. 51-71 ◽  
Author(s):  
A. Daghighi ◽  
H. Tropp ◽  
N. Dahlström ◽  
A. Klarbring
Keyword(s):  
Vertebral Column ◽  
Parameter Extraction ◽  
Surrounding Tissue ◽  
P Value ◽  
Shear Stresses ◽  
Response Variable ◽  
Geometric Models ◽  
Number Of Patients ◽  
Distortion Energy ◽  
The Impact

Background:In scoliosis, kypholordos and wedge properties of the vertebrae should be involved in determining how stress is distributed in the vertebral column. The impact is logically expected to be maximal at the apex.Aim:To introduce an algorithm for constructing artificial geometric models of the vertebral column from DICOM stacks, with the ultimate aim to obtain a formalized way to create simplistic models, which enhance and focus on wedge properties and relative tilting.Material/Methods:Our procedure requires parameter extraction from DICOM image-stacks (with PACS,IDS-7), mechanical FEM-modelling (with Matlab and Comsol). As a test implementation, models were constructed for five patients with thoracal idiopathic scoliosis with varying apex rotation. For a selection of load states, we calculated a response variable which is based upon distortion energy.Results:For the test implementation, pairwise t-tests show that our response variable is non-trivial and that it is chiefly sensitive to the transversal stresses (transversal stresses where of main interest to us, as opposed to the case of additional shear stresses, due to the lack of explicit surrounding tissue and ligaments in our model). Also, a pairwise t-test did not show a difference (n = 25, p-value≈0.084) between the cases of isotropic and orthotropic material modeling.Conclusion:A step-by-step description is given for a procedure of constructing artificial geometric models from chest CT DICOM-stacks, such that the models are appropriate for semi-global stress-analysis, where the focus is on the wedge properties and relative tilting. The method is inappropriate for analyses where the local roughness and irregularities of surfaces are wanted features. A test application hints that one particular load state possibly has a high correlation to a certain response variable (based upon distortion energy distribution on a surface of the apex), however, the number of patients is too small to draw any statistical conclusions.

Modeling of Wrinkles and Its Application in Footwear Design

2002 ◽  
Author(s):  
Fu Jing ◽  
Ajay Joneja ◽  
Angela Tam ◽  
W. F. Yuen
Keyword(s):  
Finite Element ◽  
Computer Program ◽  
Iterative Algorithm ◽  
Shape Feature ◽  
Shape Modification ◽  
B Splines ◽  
Distortion Energy ◽  
Parametric Description ◽  
Footwear Design ◽  
3D Shapes

We develop a parametric description of a wrinkle as a shape feature that may be superposed upon selected regions of a 3D surface defined by B-splines or NURBS. We show the use of such a feature in footwear design. We found that the shape modification operator for such a feature can be developed using geodesic offsets. A computer program has been implemented providing such a feature, and some examples of the output of the program are presented in this paper. We also address the need for automatically generating 2D surface developments of 3D shapes with superposed wrinkles. A finite-element style iterative algorithm is outlined for the performing this task; a new distortion energy model is developed for this algorithm in this paper.

Covalent Liquids: Tight Binding Simulation Versus Experimental Results

1997 ◽  
Vol 491 ◽  
Author(s):  
J.-P. Gaspard ◽  
C. Bichara ◽  
J. Y. Raty
Keyword(s):  
Theoretical Calculations ◽  
Qualitative Difference ◽  
Tight Binding ◽  
Repulsive Potential ◽  
Binding Model ◽  
Systematic Analysis ◽  
Coordination Numbers ◽  
Peierls Distortion ◽  
Distortion Energy ◽  
Octet Rule

ABSTRACTWe show that a simple tight binding model with a repulsive potential describes the Peierls distortions in covalent systems and the well-known octet rule. The existence and the intensity of the Peierls distortion is mainly related to the hardness of the repulsive potential as demonstrated both by theoretical calculations and by the experimental systematic analysis of liquid structures. In particular, As is threefold coordinated and Sb is sixfold coordinated in the liquid, the qualitative difference is explained by the ratio of the distortion energy ΔE to the thermal energy kBT. The Asx Sb1-x alloys show continuously varying average coordination numbers showing: the semiconductor-metal transition is continuous with concentration.In addition, we illustrate in the case of liquid Se that, tight binding Monte Carlo simulations are able to describe quantitatively the structure of liquid elements provided the Van der Waals potential is added.

scholarly journals A Distortion Energy Failure Theory for Orthotropic Materials

1972 ◽  
Vol 94 (4) ◽  
pp. 1073-1076 ◽  
Author(s):  
G. W. Forman
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Algebraic Method ◽  
Orthotropic Materials ◽  
Rational Basis ◽  
State Of Stress ◽  
Failure Theory ◽  
Distortion Energy ◽  
Energy Theory ◽  
Energy Failure

Of the numerous methods developed to predict failure of isotropic materials exposed to a three-dimensional state of stress, experimental studies tend to confirm the validity of the distortional energy theory. To date no rational basis of predicting inelastic action in an orthotropic material exposed to principle stresses coincident with the material axes has been proposed. This study assumes that distortion energy may be used to predict failure of orthotropic materials, and a usable algebraic method of predicting failure is developed.

Load Bearing and Mass Relation Contrast between Composite Shell and Alloy Shell

2013 ◽  
Vol 703 ◽  
pp. 217-220
Author(s):  
Hai Peng Gao ◽  
Meng Liu ◽  
Jun Wang
Keyword(s):  
Load Condition ◽  
Optimization Theory ◽  
State Theory ◽  
Parametric Modeling ◽  
Mass Relation ◽  
Work Efficiency ◽  
Load Bearing ◽  
Influence Curves ◽  
Weight Condition ◽  
Distortion Energy

To improve work efficiency of cabin and solve the contradiction between load bearing and mass, combining parametric modeling and optimization theory,the influence curves of load bearing on mass are proposed. Applying stress state theory, combining distortion energy theory criterion and Tsai-Wu failure criterion, shells load bearing is theoretically analysed. Contrast results are, in the same load condition, compared with alloy, the weight of composite reduces 46.2%;in the same weight condition, the load bearing of composite increases 75%. At present, the cabin load bearing is 0.04MPa, to improve work efficiency, increasing to 0.055MPa and replacing alloy by composite, the load bearing increases 37.5%, while the weight reduces 26.1%, then the contradiction between work efficiency and mass is coordinated.

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