Structural features of uranyl acrylate complexes with s-, p-, and d-monovalent metals

2019 ◽  
Vol 234 (4) ◽  
pp. 247-256 ◽  
Author(s):  
Olga A. Chekhomova ◽  
Vladislav V. Klepov ◽  
Denis V. Pushkin ◽  
Evgeny V. Alekseev ◽  
Anna V. Vologzhanina ◽  
...  
Keyword(s):  
Monovalent Cation ◽  
Structural Features ◽  
Monovalent Cations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal System ◽  
Dirichlet Tessellation ◽  
Vinyl Group

Abstract A series of uranyl acrylate complexes with s-, p-, and d- monovalent cations (Li, Na, Tl, and Ag) was synthesized and characterized by single crystal X-ray diffraction and IR spectroscopy. We demonstrated that the nature of the monovalent cation strongly affects the composition and crystal structure of an uranyl acrylate. Li[UO2(acr)3]·H2O (1, acr=CH2CHCOO−) crystallizes in the tetragonal crystal system and is built of chains which are connected through hydrogen bonding. The presence of an acrylic acid dimer in the reaction results in the monoclinic compound Na3[UO2(acr)3][UO2(acr)2.5(CH2CHCOOCH2CH2COO)0.5]2·5H2O (2), in which the acrylic dimer shares a position with both the acrylate anion and a water molecule. Tl[UO2(acr)3] (3) exists as two polymorphs and crystallizes in either P1̅ (3a) or P213 (3b) space groups. The polymorphs differ in the dimensionality, 2D for 3a and 3D for 3b, and density. Ag2[UO2(NO3)2(acr)2]·2Hacr (4) is the first example of the Ag atom coordination to the acrylate anion through the vinyl group. In 4, the Ag–C bonds enhances the connectivity of the trinuclear [Ag2UO2(acr)2(Hacr)2(NO3)2] clusters into a layered coordination polymer. A detailed structural study of the obtained compounds was performed using Voronoi-Dirichlet tessellation.

scholarly journals Analysis of the Homogeneity of Particle Refinement in Friction Stir Processing Al-Si Alloys

2010 ◽  
Vol 89-91 ◽  
pp. 85-90 ◽  
Author(s):  
Chun Y. Chan ◽  
Philip B. Prangnell ◽  
Simon J. Barnes
Keyword(s):  
Friction Stir Processing ◽  
Process Zone ◽  
Phase Particle ◽  
Processing Parameters ◽  
Second Phase ◽  
Friction Stir ◽  
Die Cast ◽  
Alloy Castings ◽  
Particle Refinement ◽  
Dirichlet Tessellation

Friction Stir Processing (FSP) has potential for locally enhancing the properties of Al-Si alloy castings, for demanding applications within the automotive industry, by greatly refining the second phase particle size. In the present study, the homogeneity of particle refinement and second phase spatial distribution within the process zone, as well as the relationship to the processing parameters, were investigated in a gravity die cast Al-Si LM24/A380 alloy, subjected to a range of FSP conditions. Detailed image analysis and the dirichlet tessellation method were used to quantify particle clustering. ‘Stop-action’ experiments were also used to study the process of particle break up, by following the behaviour through the deformation zone surrounding the tool.

Voronoi Cell Finite Element Model for Thermoelastoplastic Deformation in Random Heterogeneous Media

1994 ◽  
Vol 47 (1S) ◽  
pp. S207-S220 ◽  
Author(s):  
Suresh Moorthy ◽  
Somnath Ghosh ◽  
Yunshan Liu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Heterogeneous Media ◽  
Voronoi Cell ◽  
Element Model ◽  
Second Phase ◽  
Element Mesh ◽  
Model Composite ◽  
Elasto Plasticity ◽  
Dirichlet Tessellation

A finite element model has been developed for analysis of heterogeneous media, in which second phase inclusions are arbitrarily dispersed within a matrix. A mesh generator based on Dirichlet tessellation, discretizes the heterogeneous domain, accounting for the arbitrariness in location, shape and size of the second phase. This results in a network of convex “Voronoi” polygons which form the elements in a finite element mesh. An assumed stress hybrid formulation has been implemented for accommodating arbitrary multi-sided elements in the finite element model. Composite element formulations have been developed to incorporate the effect of second phase within each element. Formulations have been developed for thermo-elasticity, micropolar elasticity and elasto-plasticity.

Dirichlet neighbours: revisiting Dirichlet tessellation for neighbourhood analysis

2001 ◽  
Vol 25 (1) ◽  
pp. 105-117 ◽  
Author(s):  
P.J. Halls ◽  
M. Bulling ◽  
P.C.L. White ◽  
L. Garland ◽  
S. Harris
Keyword(s):  
Neighbourhood Analysis ◽  
Dirichlet Tessellation
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