Often without guidance in completing college-related tasks, first-generation students face unique challenges during the summer before college. This case study investigates this critical time period by studying a cohort of 33 newly graduated students from the same urban, public high school. Guided by social capital, college readiness, and nepantla frameworks, results shed light on students’ barriers and pathways to transitioning to postsecondary education. The authors call for an extension of college readiness frameworks to the summer before college and also problematize the notion of a college-ready student.

The high‐energy ball milling behavior of a commercially available ZrB2 powder was studied by X‐ray diffractometry and transmission electron microscopy. It is shown that ball milling is very effective in obtaining nanocrystalline ZrB2 powder. Further, the crystallite size refinement occurs through repeated brittle fracture, with the final crystal size being limited by a combination of the fracture strength of particles and the compressive stress induced by collision of balls. With this mechanism, the crystallite size first decreases rapidly, then gradually, and finally approaches to an asymptotic limit as the ball‐milling time increases. Additionally, the higher the ball‐to‐powder weight ratio, the faster the decrease in the crystallite size and the smaller the ultimate crystallite size.

No abstract

The effect of graphite addition on the high‐energy ball‐milling behavior of zirconium diboride (ZrB2) powder is investigated. It is shown that, regardless of presence or absence of graphite during ball milling, comminution occurs by repeated brittle fracture followed by cold‐welding, thereby resulting in the formation of agglomerates comprising primary particles of 10 nm in average diameter. However, addition of 2 wt% graphite leads to the formation of nanometer agglomerates (∼50 nm) rather than the submicrometer counterparts (∼120 nm) formed in the absence of graphite. The simultaneous attainment of reduced agglomerate size and homogeneous graphite dispersion at the nanometer scale can have important implications for the ultra‐high‐temperature ceramics community because of the expected twofold enhancement in the sintering kinetics of the compacts made from these nanoscale ZrB2 powders and the simplification of the processing routine.

No abstract