The formation of topologically close-packed (TCP) phases in nickel-base superalloys is an issue of increasing importance as alloys are designed with higher refractory element contents to meet the requirements of next generation turbine engines. This review considers the factors that affect an alloy's susceptibility to TCP formation. In particular, the debate surrounding the effect of certain individual elements, such as Co and Re, in promoting or suppressing TCP formation is examined alongside the various mechanisms that have been proposed to account for this behaviour. In addition, the detrimental effects of these phases on the alloy's mechanical properties are discussed, including crack initiation at precipitates, depletion of solid solution strengthening refractory elements and the effect on γ/γʹ rafting behaviour.

Teacher satisfaction is a key affective reaction to working conditions and an important predictor of teacher attrition. Teacher evaluation as a tool for measuring teacher quality has been one source of teacher stress in recent years in the United States. There is a growing body of evidence on how to evaluate teachers in ways which support their growth and development as practitioners. For this study, we inquired: What is the relationship between supportive teacher evaluation experiences and U.S. teachers’ overall job satisfaction? To answer this question, we employed a multilevel regression analysis to multiply-imputed data on U.S. lower-secondary teachers’ experiences from the 2013 Teaching and Learning International Survey (TALIS). We found a small, positive relationship between the perceptions of supportive teacher evaluation experiences and U.S. secondary teachers’ satisfaction after controlling for other important teacher and school characteristics and working conditions. Further, teachers who felt their evaluation led to positive changes in their practice had higher satisfaction. Teachers whose primary evaluator was a fellow teacher as opposed to the principal also had higher satisfaction on average. We discuss the implications of these findings for school leaders as well as future teacher evaluation policy.

The effect of Nb on the properties and microstructure of two novel powder metallurgy (P/M) Ni-based superalloys was evaluated, and the results critically compared with the Rolls-Royce alloy RR1000. The Nb-containing alloy was found to exhibit improved tensile and creep properties as well as superior oxidation resistance compared with both RR1000 and the Nb-free variant tested. The beneficial effect of Nb on the tensile and creep properties was due to the microstructures obtained following the post-solution heat treatments, which led to a higher γ′ volume fraction and a finer tertiary γ′ distribution. In addition, an increase in the anti-phase-boundary energy of the γ′ phase is also expected with the addition of Nb, further contributing to the strength of the material. However, these modifications in the γ′ distribution detrimentally affect the dwell fatigue crack-growth behavior of the material, although this behavior can be improved through modified heat treatments. The oxidation resistance of the Nb-containing alloy was also enhanced as Nb is believed to accelerate the formation of a defect-free Cr2O3 scale. Overall, both developmental alloys, with and without the addition of Nb, were found to exhibit superior properties than RR1000.

To advance a framework of indicators that promotes imple mentation of math standards under the Every Student Succeeds Act (ESSA), we tested a conceptual model of the resources and processes within schools that influence the opportunity to learn mathematics (OTL) in the classroom using a recent administration of the 2011 Trends in International Math and Science Study (TIMSS 2011). There is potential benefit to state departments and systemlevel practitioners from more information about how schools might influence student access to college and careerready curriculum. Such information has the potential to shape the kinds of indicators stakeholders put in place to target problems and formulate solutions for math learning. Research Design: To test the fit of our hypothesized model of math content and instruction OTL, we applied structural equation modeling techniques to school and classroom data from 425 fourthgrade U.S. math teachers in TIMSS 2011. Findings: We found a direct influence of instructional leadership on

The overuse of lecture-based approaches for instruction in university courses may have limited student access to knowledge, particularly the transfer of complex concepts, such as central limit theorem in statistics. This study seeks to contribute to empirical research regarding the effectiveness of serious educational games (SEGs) to increase undergraduates’ conceptual understanding and affective interest in statistics. An experimental design was used to test the efficacy of an SEG, Deadly Distribution, which simulates a real-world context to learn and interact with statistics concepts, compared to traditional notes and homework problems, as supplements to instruction in addition to class lectures. Students who played the game had similar increases in academic growth of conceptual knowledge as students who studied traditional course material. Furthermore, this treatment group had a significant increase in affective outcomes compared to the control group. These findings extend the current literature, which is mixed and sparse, on the effectiveness of SEGs in the undergraduate classroom. In an undergraduate introductory statistics course, an SEG might be an effective substitute for traditional study time of course materials outside of class to increase their affect toward the subject matter and produce similar gains for students who might not otherwise study.