rhombic dodecahedron
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Author(s):  
Junke Li ◽  
Mei Li ◽  
Zhiliang Jin

S-scheme surface heterojunction was constructed in Co3S4@Mo2S3 via the stepwise hydrothermal method. The rhombic dodecahedron cobalt-based metal-organic zeolite imidazole framework (ZIF-67) is used as the cobalt source and template to...


2021 ◽  
Author(s):  
Inderjot Kaur ◽  
Prashant Singh

Abstract Open-cell metal foams are known for their superior heat dissipation capabilities. The morphological, pressure-drop and heat transfer characteristics of stochastic metal foams manufactured through traditional 'foaming' process are well established in the literature. Employment of stochastic metal foams in next generation heat exchangers, is however, challenged by the irregularity in the pore-and fiber-geometries, limited control on the pore-volume, and an inherent necessity of a bonding agent between foam and heat source. On the other hand, additive manufacturing is an emerging technology that is capable of printing complex user-defined unit cell topologies with customized fiber shapes directly on the heated substrates. Moreover, the user-defined regular lattices are capable of exhibiting better thermal and mechanical properties than stochastic metal foams. In this paper, we present a numerical investigation on fully periodic unit-cells of three different topologies, viz. Tetrakaidecahedron (TKD), Rhombic-dodecahedron (DDC), and Octet with air as the working fluid. Pressure gradient, interfacial heat transfer coefficient, friction factor, and Nusselt number are reported for each topology. Rhombic-dodecahedron yielded in the highest average interfacial heat transfer coefficient whereas Octet incurred the highest flow losses. Pore diameter, defined as the maximum diameter of a sphere passing through the polygonal openings of the structures, when used as the characteristics length scale for the presentation of Nusselt number and Reynolds number, resulted in a single trendline for all the three topologies.


Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1325
Author(s):  
Yitao Cai ◽  
Zhengqi Cao ◽  
Fei Liu ◽  
Kan Li ◽  
Long Li ◽  
...  

Most of the diamond deposits in China are in the North China Craton. In addition to gem diamonds in kimberlite, a large number of microdiamonds have also been discovered in alkaline dolerites. These microdiamonds show very different characteristics from those recovered in kimberlite. Here, we report the morphology, colour, nitrogen contents, and carbon isotopic compositions of the diamonds recovered from the alkalic dolerites in eastern China. The microdiamonds are mainly cube and rhombic dodecahedron with diameters of 0.2 to 0.6 mm. Infrared spectrum analysis shows that these microdiamonds are mostly type Ib with a small amount of type Ia. The Y centre is obvious in type Ib diamond. Modelling mantle residence times for the IaAB diamonds is about 550 Ma. Nitrogen contents of the diamonds range from 4.5–503 ppm, with a median value of 173 ppm. The total δ13C range of the microdiamonds varies between −18.6 and −21.1‰ and are similar to those of ophiolite diamond.


2021 ◽  
Vol 60 (17) ◽  
pp. 13528-13538
Author(s):  
Adrien Schlachter ◽  
Kevin Tanner ◽  
Rebecca Scheel ◽  
Paul-Ludovic Karsenti ◽  
Carsten Strohmann ◽  
...  

2021 ◽  
Vol 318 ◽  
pp. 71-81
Author(s):  
Basma Eltlhawy ◽  
Tawfik El-Midany ◽  
Noha Fouda ◽  
Ibrahim Eldesouky

The current research presents a novel porous tibia implant design based on porous structure. The implant proximal portion was designed as a porous rhombic dodecahedron structure with 500 μm pore size. Finite element method (FEM) was used to assess the stem behavior under compressive loading compared to a solid stem model. CATIA V5R18 was used for modeling both rhombic dodecahedron and full solid models. Static structural analysis was carried out using ANSYS R18.1 to asses the implant designs. The results indicated enhanced clinical performance of tibial-knee implants compared to the solid titanium implant via increasing the maximum von-Mises stresses by 64% under the tibial tray in porous implant which reduce stress shielding. Also, the maximum shear stress developed in bone/implant interface was reduced by 68% combined with relieving the stress concentration under the stem tip to relieve patients' pain. Finally, porous implants provide cavities for bone ingrowth which improve implant fixation.


2021 ◽  
Vol 259 ◽  
pp. 113500
Author(s):  
Boning Yu ◽  
Yuming Li ◽  
Boussad Abbes ◽  
Baoyi Yu ◽  
Shujun Li

2020 ◽  
Vol 25 (01) ◽  
pp. 1-9
Author(s):  
Yuanyuan Fang ◽  
Laihai Huang ◽  
Ningchao Liu ◽  
Guoliang Zhu ◽  
Jian Rong ◽  
...  

A series of different metal centered 5,15-Bis(4-aminophenyl)-10,20-bis(4-bromophenyl)porphyrins (PorM) where M = H2, MnOAc, FeCl, Co or Zn were synthesized, and then encapsulated in zeolite imidazole framework-8 (ZIF-8) by typical template directed strategy to generate PorM@ZIF-8 metal organic frameworks (MOFs). These composites were characterized by UV-vis, FTIR, XRD, FESEM and HRTEM methods. Each prepared PorM@ZIF-8 MOF retained the molecular structure of porphyrin and crystal structure of ZIF-8. It is clearly shown that porphyrin centered metal ions will affect MOFs morphology. Both PorH2@ZIF-8 and PorZn@ZIF-8 gave a rhombic dodecahedron, PorMnOAc@ZIF-8 gave a truncated hexagonal prism-like structure, while no specific structures were obtained for PorFeCl@ZIF-8 and PorCo@ZIF-8 due to aggregation as characterized by FESEM spectrum. Oxygen reduction catalytic ability of ZIF-8, PorM and PorM@ZIF-8 were measured in alkaline condition (0.1 M KOH) with the number of electrons transferred being [Formula: see text] = 2.20–2.60 and generating HO[Formula: see text] as the oxygen reduction product. The catalytic property slightly increased after the porphyrin was encapsulated, due possibly to the capacity limit, inappropriate molecular distance or the direction of encapsulated porphyrin molecular.


2020 ◽  
Vol 4 (1) ◽  
pp. 143-158
Author(s):  
Ranita Biswas ◽  
Gaëlle Largeteau-Skapin ◽  
Rita Zrour ◽  
Eric Andres

AbstractRhombic dodecahedron is a space filling polyhedron which represents the close packing of spheres in 3D space and the Voronoi structures of the face centered cubic (FCC) lattice. In this paper, we describe a new coordinate system where every 3-integer coordinates grid point corresponds to a rhombic dodecahedron centroid. In order to illustrate the interest of the new coordinate system, we propose the characterization of 3D digital plane with its topological features, such as the interrelation between the thickness of the digital plane and the separability constraint we aim to obtain. We also present the characterization of 3D digital lines and study it as the intersection of multiple digital planes. Characterization of 3D digital sphere with relevant topological features is proposed as well along with the 48-symmetry appearing in the new coordinate system.


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