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Over a decade ago, it was shown that every edge unfolding of the Platonic solids was without self-overlap, yielding a valid net. Recent work has extended this property to their higher-dimensional analogs: the 4-cube, 4-simplex, and 4-orthoplex. We present an interactive visualization that allows the user to unfold these polytopes by drawing on their dual 1-skeleton graph., LIPIcs, Vol. 224, 38th International Symposium on Computational Geometry (SoCG 2022), pages 67:1-67:4

Women and people of color remain dramatically underrepresented among computing faculty, and improvements in demographic diversity are slow and uneven. Effective diversification strategies depend on quantifying the correlates, causes, and trends of diversity in the field. But field-level demographic changes are driven by subfield hiring dynamics because faculty searches are typically at the subfield level. Here, we quantify and forecast variations in the demographic composition of the subfields of computing using a comprehensive database of training and employment records for 6882 tenure-track faculty from 269 PhD-granting computing departments in the United States, linked with 327,969 publications. We find that subfield prestige correlates with gender inequality, such that faculty working in computing subfields with more women tend to hold positions at less prestigious institutions. In contrast, we find no significant evidence of racial or socioeconomic differences by subfield. Tracking representation over time, we find steady progress toward gender equality in all subfields, but more prestigious subfields tend to be roughly 25 years behind the less prestigious subfields in gender representation. These results illustrate how the choice of subfield in a faculty search can shape a department's gender diversity., Comment: 20 pages, 12 figures, 5 tables

Selective Laser Melting (SLM) has shown its advantage in producing metal parts with fully density, complex shape and excellent mechanical properties. However, there are many challenges ahead applying this technology to build ceramic structure. Cracking tendency is the main problem, due to high thermal gradient and temperature difference during laser melting and low plastic formation of ceramic materials. This paper presents an experimental investigation of building an oxide ceramic by selective laser melting technology, based on powder bed. A mixture of ZrO2/Al2O3 ceramic powder was used. To decrease the thermal gradient, the thin powder layer was heated by a high energy fiber laser source. Parametric study was presented, including laser power, scanning speed, powder component ratio and heating strategy. Published version

To understand the formation mechanism of catalyst inclusions in carbon nanotubes, multi-walled carbon nanotubes were grown via catalytic decomposition of C2H4 on a 50-nm-thick nickel film at 725 C. Atomic force microscopy, glancing incidence X-ray diffraction, field emission scanning electron microscopy, and high resolution transmission electron microscopy were employed to examine the evolution of the nickel film and the structure of the nanotubes. It was found that pretreating of the nickel film resulted in lots of small nanoparticles extruding on the surface, among big ones, serving as seeds for the growth of tubes. The inner walls of a few tubes were sealed internally by multiple elongated “beads-like,” “bullet-shaped” or “needle-shaped” nickel inclusions. The inclusions retained the face-centered-cubic crystalline structure of the as-sputtered nickel film. The entrapping of nickel inclusions is explained by a continuous tip growth model. A conservative upper limit of the nickel layer thickness (50 nm) was estimated for growing high purity carbon nanotubes.

Nanocomposite thin films comprise at least two phases, a nanocrystalline phase and a matrix phase, where the matrix can be either nanocrystalline or amorphous phase. The general characteristics of nanocomposite coating are a host material with another material homogenously embedded in it, with one (or both) of these materials having a characteristic length scale of 1-100 ran as schematically illustrated in Fig. 1-1.

This research concentrated on the development of high toughness cermet by applying PSSS treatment and changing the composition of the materials, especially the composition of the binder phase. Ceramic powders of Ti(CN), TaC, WC were mixed, compacted and heat-treated at high temperatures to form (Ti, W, Ta)(C, N) solid solution, which was then ball-milled to fine powders before mixing with metallic binder and compacted. ARP 66/91