Anticorrosion and antioxidation surface treatments such as paint or anodization are a foundational component in nearly all industries. Graphene, a single-atom-thick sheet of carbon with impressive impermeability to gases, seems to hold promise as an effective anticorrosion barrier, and recent work supports this hope. We perform a complete study of the short- and long-term performance of graphene coatings for Cu and Si substrates. Our work reveals that although graphene indeed offers effective short-term oxidation protection, over long time scales it promotes more extensive wet corrosion than that seen for an initially bare, unprotected Cu surface. This surprising result has important implications for future scientific studies and industrial applications. In addition to informing any future work on graphene as a protective coating, the results presented here have implications for graphene's performance in a wide range of applications.

Background: Mentoring supports professional success in a myriad of fields; in the physical sciences, mentoring increases the retention of diverse groups of students. While physics education has made progress in classifying the availability and structural components related to mentoring programs, little is known about the qualitative nature of mentoring relationships. This article draws from frameworks in science identity and belongs to analyze the nature of relationships in the mentoring program offered by the Sundial Project at Arizona State University, which aims to help new students with diverse backgrounds succeed in physics and related majors. To provide insight into mentoring relationships, we analyze over 150 reports submitted by mentors and mentees in a near-peer mentoring program. Results: Mentoring groups enjoyed positive rapport and often remarked upon becoming friends. As such, mentoring relationships provided mentees with both psychosocial and academic support. Mentoring supported students to deal with a wide variety of topics, ranging from academic to personal, according to the needs of individual mentees. Moreover, outcomes of students in the mentoring program were favorable; the mean GPA of participating mentees was 3.49 for their first college semester. Conclusions: Mentors acted both as guides who shared information and as caring friends who providing psychosocial support, including normalizing struggle. These connections supported students to develop a sense of belonging and positive science identities.

We have identified five new R Coronae Borealis (RCB) stars in the Galactic bulge using the MACHO Project photometry database, raising the total number of known Galactic RCB stars to about 40. We have obtained spectra to confirm the identifications. The fact that four out of the five newly identified RCB stars are "cool" (T ef f < 6000 K) rather than "warm" (T ef f > 6000 K) suggests that the preponderance of warm RCB stars among the existing sample is a selection bias. These cool RCB stars are redder and fainter than their warm counterparts and may have been missed in surveys done with blue plates. Based on the number of new RCB stars discovered in the MACHO bulge fields, there may be ∼250 RCB stars in the reddened "exclusion" zone toward the bulge.