Space Filling with Rhombic Dodecahedra and Cubic Close Packing

2008 ◽  
Keyword(s):  
Close Packing ◽  
Space Filling ◽  
Rhombic Dodecahedra

Feasible Build Orientations for Self-Supporting Fused Deposition Manufacture: A Novel Approach to Space-Filling Tesselated Geometries

2013 ◽  
Vol 633 ◽  
pp. 148-168 ◽  
Author(s):  
Martin Leary ◽  
Mohammad Babaee ◽  
Milan Brandt ◽  
Aleksandar Subic
Keyword(s):  
Close Packing ◽  
Biocompatible Materials ◽  
Cellular Structures ◽  
Additive Manufacture ◽  
Support Material ◽  
Space Filling ◽  
Additional Material ◽  
Fused Deposition ◽  
Manufacture Process ◽  
Novel Approach

Support material is often utilised in additive manufacture to enable geometries that are not otherwise self-supporting. Despite the associated opportunities for innovation, the use of support material also introduces a series of limitations: additional material cost, cost of removal of support material, potential contamination of biocompatible materials, and entrapment of support material within cellular structures. This work presents a strategy for minimising the use of support material by comparing the geometric limits of an additive manufacture process to the build angles that exist within a proposed geometry. This method generates a feasibility map of the feasible build orientations for a proposed geometry with a given process. The method is applied to polyhedra that are suitable for close packing to identify space-filling tessellated structures that can be self-supporting. The integrity of an FDM process is quantified, and using the associated feasibility map, self-supporting polyhedra are manufactured. These polyhedra are integrated with non-trivial geometries to achieve a reduction in consumed material of approximately 50%. Nomenclature

Crystal structure images of large gold clusters and growing crystals by HRTEM

1984 ◽  
Vol 42 ◽  
pp. 428-429
Author(s):  
L.R. Wallenberg ◽  
J.-O. Bovin ◽  
G. Schmid
Keyword(s):  
Crystal Structure ◽  
Nucleation And Growth ◽  
Close Packing ◽  
Gold Clusters ◽  
Molecular Weight Determination ◽  
Growth Mechanisms ◽  
Starting Point ◽  
Different Types ◽  
Nucleation And Growth Mechanisms ◽  
Points Of View

Metallic clusters are interesting from various points of view, e.g. as a mean of spreading expensive catalysts on a support, or following heterogeneous and homogeneous catalytic events. It is also possible to study nucleation and growth mechanisms for crystals with the cluster as known starting point.Gold-clusters containing 55 atoms were manufactured by reducing (C6H5)3PAuCl with B2H6 in benzene. The chemical composition was found to be Au9.2[P(C6H5)3]2Cl. Molecular-weight determination by means of an ultracentrifuge gave the formula Au55[P(C6H5)3]Cl6 A model was proposed from Mössbauer spectra by Schmid et al. with cubic close-packing of the 55 gold atoms in a cubeoctahedron as shown in Fig 1. The cluster is almost completely isolated from the surroundings by the twelve triphenylphosphane groups situated in each corner, and the chlorine atoms on the centre of the 3x3 square surfaces. This gives four groups of gold atoms, depending on the different types of surrounding.

A Robust, Porous and Solution-Processable Molecular Crystal Containing Multiple Donor-Acceptor Units

2019 ◽  
Author(s):  
Shengxian Cheng ◽  
Xiaoxia Ma, ◽  
Yonghe He ◽  
Jun He ◽  
Matthias Zeller ◽  
...  
Keyword(s):  
Molecular Crystal ◽  
Bulk Sample ◽  
Intermolecular Forces ◽  
Close Packing ◽  
Molecular Solids ◽  
Molecular Scaffold ◽  
Excellent Thermal Stability ◽  
Crystalline Order ◽  
Donor Acceptor ◽  
Open Packing

We report a curious porous molecular crystal that is devoid of the common traits of related systems. Namely, the molecule does not rely on directional hydrogen bonds to enforce open packing; and it offers neither large concave faces (i.e., high internal free volume) to frustrate close packing, nor any inherently built-in cavity like in the class of organic cages. Instead, the permanent porosity (as unveiled by the X-ray crystal structure and CO<sub>2</sub> sorption studies) arises from the strong push-pull units built into a Sierpinski-like molecule that features four symmetrically backfolded (<b>SBF</b>) side arms. Each side arm consists of the 1,1,4,4-tetracyanobuta-1,3-diene acceptor (TCBD) coupled with the dimethylaminophenyl donor, which is conveniently installed by a cycloaddition-retroelectrocyclization (CA-RE) reaction. Unlike the poor/fragile crystalline order of many porous molecular solids, the molecule here readily crystallizes and the crystalline phase can be easily deposited into thin films from solutions. Moreover, both the bulk sample and thin film exhibit excellent thermal stability with the porous crystalline order maintained even at 200 °C. The intermolecular forces underlying this robust porous molecular crystal likely include the strong dipole interactions and the multiple C···N and C···O short contacts afforded by the strongly donating and accepting groups integrated within the rigid molecular scaffold.

Region of Interest Based MRI Brain Image Compression Using Peano Space Filling Curve

2016 ◽  
Vol 11 (2) ◽  
pp. 114-120 ◽  
Author(s):  
C. Peter Devadoss ◽  
Balasubramanian Sankaragomathi ◽  
Thirugnanasambantham Monica
Keyword(s):  
Image Compression ◽  
Region Of Interest ◽  
Space Filling ◽  
Brain Image ◽  
Space Filling Curve ◽  
Mri Brain ◽  
Filling Curve ◽  
Mri Brain Image

Quantum-chemical analysis of small silver clusters

1987 ◽  
Vol 52 (7) ◽  
pp. 1652-1657 ◽  
Author(s):  
Grigorii V. Gadiyak ◽  
Yurii N. Morokov ◽  
Mojmír Tomášek
Keyword(s):  
Hard Spheres ◽  
Electronic Configuration ◽  
Close Packing ◽  
Basis Sets ◽  
Silver Clusters ◽  
Quantum Chemical Analysis ◽  
Spin Distribution ◽  
Spin Polarized ◽  
Atomic Silver ◽  
Equilibrium Geometries

Total energy calculations of three- and four-atomic silver clusters have been performed by the spin-polarized version of the CNDO/2 method to get the most stable equilibrium geometries, atomization energies, and charge and spin distribution on the atoms for three different basis sets: {s}, {sp}, and {spd}. When viewed from the equilateral triangle and square geometries, the last electronic configuration, i.e. the {spd} one, appears to be most stable with respect to the geometrical deformations considered. In this case, the behaviour of the atoms of both clusters resembles that of hard spheres (i.e. close-packing).

Ultra-smooth and space-filling mineral films generated via particle accretion processes

2019 ◽  
Vol 4 (6) ◽  
pp. 1388-1393
Author(s):  
Joe Harris ◽  
Ingo P. Mey ◽  
Corinna F. Böhm ◽  
Thi Thanh Huyen Trinh ◽  
Simon Leupold ◽  
...  
Keyword(s):  
Space Filling ◽  
Smooth Space ◽  
Packing Densities

Well-tuned bioinspired mineralization via liquid mineral precursors yields ultra-smooth, space-filling bodies, transgressing the supremum of packing densities of nonclassical crystallization.

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