Elastic Fields in a Polyhedral Inclusion With Uniform Eigenstrains and Related Problems

2000 ◽  
Vol 68 (3) ◽  
pp. 441-452 ◽  
Author(s):  
H. Nozaki ◽  
M. Taya

In this paper, the elastic field in an infinite elastic body containing a polyhedral inclusion with uniform eigenstrains is investigated. Exact solutions are obtained for the stress field in and around a fully general polyhedron, i.e., an arbitrary bounded region of three-dimensional space with a piecewise planner boundary. Numerical results are presented for the stress field and the strain energy for several major polyhedra and the effective stiffness of a composite with regular polyhedral inhomogeneities. It is found that the stresses at the center of a polyhedral inclusion with uniaxial eigenstrain do not coincide with those for a spherical inclusion (Eshelby’s solution) except for dodecahedron and icosahedron which belong to icosidodeca family, i.e., highly symmetrical structure.

2010 ◽  
Vol 21 (01) ◽  
pp. 11-32 ◽  
Author(s):  
CLAUDIA CHINOSI ◽  
LUCIA DELLA CROCE ◽  
DANIELE FUNARO

Electromagnetic waves, solving the full set of Maxwell equations in vacuum, are numerically computed. These waves occupy a fixed bounded region of the three-dimensional space, topologically equivalent to a toroid. Thus, their fluid dynamics analogs are vortex rings. An analysis of the shape of the sections of the rings, depending on the angular speed of rotation and the major diameter, is carried out. Successively, spherical electromagnetic vortex rings of Hill's type are taken into consideration. For some interesting peculiar configurations, explicit numerical solutions are exhibited.


Author(s):  
Shobhit Singhal ◽  
Jitendra P. Khatait

Abstract Flexible medical instruments undergo looping during insertion and navigation inside the human body. It makes the control of the distal end difficult and raises safety concerns. This paper proposes the minimum strain energy concept to get the deformed shape of a flexible instrument in three-dimensional space. A B\'{e}zier curve is used to define the trajectory of the deformed shape under different loading conditions and constraints. Looping behavior is studied for different end shortening conditions. The effect of end twist on looping behavior is studied. It is observed that end twist leads to early onset of out of plane deformation leading to looping. The strain energy plot gives an insight into the behavior of these instruments with respect to end shortening and twist. The strain energy plot shows the minimum value for $2\pi$ end twist. Therefore, the instrument tends to go for looping if the end twist is present. Force and torque characteristics are obtained which will lead to the design and control of these instruments. Force and torque plots show negative stiffness when the instrument is going for looping. The un-looping phenomenon is also discussed and a strategy is proposed to mitigate looping. The proposed modeling approach can be utilized to address the complex behavior of a flexible instrument in medical as well as in other industrial applications. The insight developed will help in designing and developing control for safe and reliable usage of flexible instruments in various domains.


1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.


2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>


1992 ◽  
Author(s):  
Fred H. Previc ◽  
Lisa F. Weinstein ◽  
Bruno G. Breitmeyer

Author(s):  
Raimo Hartmann ◽  
Hannah Jeckel ◽  
Eric Jelli ◽  
Praveen K. Singh ◽  
Sanika Vaidya ◽  
...  

AbstractBiofilms are microbial communities that represent a highly abundant form of microbial life on Earth. Inside biofilms, phenotypic and genotypic variations occur in three-dimensional space and time; microscopy and quantitative image analysis are therefore crucial for elucidating their functions. Here, we present BiofilmQ—a comprehensive image cytometry software tool for the automated and high-throughput quantification, analysis and visualization of numerous biofilm-internal and whole-biofilm properties in three-dimensional space and time.


i-com ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 67-85
Author(s):  
Matthias Weise ◽  
Raphael Zender ◽  
Ulrike Lucke

AbstractThe selection and manipulation of objects in Virtual Reality face application developers with a substantial challenge as they need to ensure a seamless interaction in three-dimensional space. Assessing the advantages and disadvantages of selection and manipulation techniques in specific scenarios and regarding usability and user experience is a mandatory task to find suitable forms of interaction. In this article, we take a look at the most common issues arising in the interaction with objects in VR. We present a taxonomy allowing the classification of techniques regarding multiple dimensions. The issues are then associated with these dimensions. Furthermore, we analyze the results of a study comparing multiple selection techniques and present a tool allowing developers of VR applications to search for appropriate selection and manipulation techniques and to get scenario dependent suggestions based on the data of the executed study.


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