Ceramic slurries with different contents of Al 2 O 3 were formulated and alumina ceramic parts with promising surface morphology were fabricated by using digital light processing photopolymerization-based additive manufacturing technology. The factors influencing curing depth of the slurries were studied, while the effects of powder content on shrinkage of the green bodies and microstructure, density, and hardness of the sintered bodies were evaluated.Although the curing depth was decreased with increasing content of Al 2 O 3 , all the five groups of slurries could be well cured, as the exposure time was set to be 16 s. According to TG-DTG curves, the weight loss of the samples was completed at about 580 • C. Samples from the slurries with 70 and 75 wt.% Al 2 O 3 had dense microstructure, without obvious cracks at both the macro-and micro-scales. Furthermore, with increasing content of Al 2 O 3 in slurries, the bulk density and hardness of sintered bodies were increased. It is believed that our results could be used as a reference for the fabrication of alumina ceramics through additive manufacturing technology.

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Proper proximality of a countable group is a notion that was introduced by Boutonnet, Ioana and Peterson as a tool to study rigidity properties of certain von Neumann algebras associated to groups or ergodic group actions. In the present paper, we establish the proper proximality of many groups acting on nonpositively curved spaces.First, these include many countable groups G acting properly nonelementarily by isometries on a proper CAT(0) space X. More precisely, proper proximality holds in the presence of rank one isometries or when X is a locally thick affine building with a minimal G-action. As a consequence of Rank Rigidity, we derive the proper proximality of all countable nonelementary CAT(0) cubical groups, and of all countable groups acting properly cocompactly nonelementarily by isometries on either a Hadamard manifold with no Euclidean factor, or on a 2-dimensional piecewise Euclidean CAT(0) simplicial complex.Second, we establish the proper proximality of many hierarchically hyperbolic groups. These include the mapping class groups of connected orientable finite-type boundaryless surfaces (apart from a few low-complexity cases), thus answering a question raised by Boutonnet, Ioana and Peterson. We also prove the proper proximality of all subgroups acting nonelementarily on the curve graph.In view of work of Boutonnet, Ioana and Peterson, our results have applications to structural and rigidity results for von Neumann algebras associated to all the above groups and their ergodic actions.

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This is the second part of a series of papers concerning Morse quasiflats -higher dimensional analogs of Morse quasigeodesics. Our focus here is on their asymptotic structure. In metric spaces with convex geodesic bicombings, we prove asymptotic conicality, uniqueness of tangent cones at infinity and Euclidean volume growth rigidity. Moreover, we provide some first applications.