Three-dimensional structural evolution and kinematics of the Piedemonte Llanero, Central Llanos foothills, Eastern Cordillera, Colombia

2012 ◽  
Vol 39 ◽  
pp. 216-227 ◽  
Author(s):  
Obi Egbue ◽  
James Kellogg
Keyword(s):  
Three Dimensional ◽  
Structural Evolution ◽  
Eastern Cordillera

Equivalent Stress Analysis of Piercing Process in Diescher’s Mill Using Finite Element Method

2013 ◽  
Vol 648 ◽  
pp. 170-173
Author(s):  
Lu Lu ◽  
Zhao Xu Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Structural Evolution ◽  
Work Piece ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Distribution Of Stress ◽  
Element Method

In this paper, the simulation of the piercing process is performed by the three dimensional finite element method in Diescher’s mill. After a short description of the problem the numerical model of the process is described. The simulated results visualize dynamic evolution of equivalent stress, especially inside the work-piece. The non-uniform distribution of stress on the internal and external surface of the work-piece is a distinct characteristic of processing tube piercing. And it is the basic data for improving tool and design, predicting, damage and controlling the micro-structural evolution of processing tube piercing.

scholarly journals Structural Evolution, Redox Mechanism, and Ionic Diffusion in Rhombohedral Na2FeFe(CN)6 for Sodium-Ion Batteries: First-Principles Calculations

2022 ◽  
Author(s):  
Ya-Ping Wang ◽  
B. P. Hou ◽  
Xin-Rui Cao ◽  
Shunqing Wu ◽  
Zi-Zhong Zhu
Keyword(s):  
First Principles ◽  
Rational Design ◽  
Low Cost ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Structural Evolution ◽  
Sodium Ion ◽  
High Rate ◽  
Sodium Ion Batteries ◽  
First Principles Calculations

Abstract Prussian blue analogs (Na2FeFe(CN)6) have been regarded as potential cathode materials for sodium-ion batteries (SIBs) due to their low-cost iron resources and open framework. Herein, the detailed first-principles calculations have been performed to investigate the electrochemical properties of NaxFeFe(CN)6 during Na ion extraction. The material undergoes a phase transition from a dense rhombohedral to open cubic structure upon half-desodiation, which is resulted from competition of the Na−N Coulomb attraction and d−π covalent bonding of Fe−N. The analyses on the density of states, magnetic moments and Bader charges of NaxFeFe(CN)6 reveal that there involve in the successive redox reactions of high-spin Fe2+/Fe3+ and low-spin Fe2+/Fe3+ couples during desodiation. Moreover, the facile three-dimensional diffusion channels for Na+ ions exhibit low diffusion barriers of 0.4 eV ~ 0.44 eV, which ensures a rapid Na+ transport in the NaxFeFe(CN)6 framework, contributing to high rate performance of the battery. This study gives a deeper understanding of the electrochemical mechanisms of NaxFeFe(CN)6 during Na+ extraction, which is beneficial for the rational design of superior PBA cathodes for SIBs.

scholarly journals Three-dimensional structural evolution of the cuttlefish Sepia officinalis shell from embryo to adult stages

2019 ◽  
Vol 16 (158) ◽  
pp. 20190175 ◽  
Author(s):  
Charles Le Pabic ◽  
Julien Derr ◽  
Gilles Luquet ◽  
Pascal-Jean Lopez ◽  
Laure Bonnaud-Ponticelli
Keyword(s):  
Internal Structure ◽  
Three Dimensional ◽  
Structural Evolution ◽  
Sepia Officinalis ◽  
Axial Tomography ◽  
Physical Measurements ◽  
Life Cycle Stages ◽  
Embryonic Life ◽  
Isolated Points ◽  
External Forces

The cuttlefish shell is an internal structure with a composition and general organization unique among molluscs. Its formation and the structure–function relation are explored during Sepia officinalis development, using computerized axial tomography scanning (CAT-scan) three-dimensional analyses coupled to physical measurements and modelling. In addition to the evolution of the overall form, modifications of the internal structure were identified from the last third embryonic stages to adult. Most of these changes can be correlated to life cycle stages and environmental constraints. Protected by the capsule during embryonic life, the first internal chambers are sustained by isolated pillars formed from the dorsal to the ventral septum. After hatching, the formation of pillars appears to be a progressive process from isolated points to interconnected pillars forming a wall-delineated labyrinthine structure. We analysed the interpillar space, the connectivity and the tortuosity of the labyrinth. The labyrinthine pillar network is complete just prior to the wintering migration, probably to sustain the need to adapt to high pressure and to allow buoyancy regulation. At that time, the connectivity in the pillar network is compensated by an increase in tortuosity, most probably to reduce liquid diffusion in the shell. Altogether these results suggest adjustment of internal calcified structure development to both external forces and physiological needs.

Structural Evolution During the Sol to Gel Transition of Silicon-Alkoxide Based Sols Observed by Cryogenic Transmission Electron Microscopy (CRYO-TEM)

1988 ◽  
Vol 121 ◽  
Author(s):  
Joseph K. Bailey ◽  
Martha L. Mecartney
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Three Dimensional ◽  
Structural Evolution ◽  
Gel Structure ◽  
Silicon Alkoxide ◽  
Cryogenic Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Acid And Base ◽  
Acid Catalyzed

ABSTRACTThe gelation reaction for tetraethoxysilane in both acid and base catalyzed environments was studied using cryogenic transmission electron microscopy. The evolution of the gel structure was observed in wet samples by the technique of fast-freeze vitrification, in which the three dimensional gel structure is preserved in vitreous solvent. The sample is then observed in the electron microscope using a cold stage. Samples were prepared and allowed to react until a specific point of gelation was reached, then were vitrified at that point. Results from this technique show a coarse network structure for base catalyzed gels. This network is composed of silica clusters ≈40Å in size. The acid catalyzed gels show an extremely fine texture (<10Å) at end point of gelation. The structures at intermediate stages of gelation were also determined.

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