The tensile strengths of Nextel™ 720 fibers as well as tows and minicomposites made of these fibers were measured to study the effects of monazite coating at room temperature (RT) and 1200°C (HT). Tests were conducted on as-received materials (called unsoaked) as well as materials that had been thermally soaked at HT for 100 hours. Weibull analysis of fiber strength data shows close agreement between the Weibull modulus obtained from the statistical fracture distribution and the modulus obtained from a study of the gage length dependence of strength. The monazite coating does not change the RT strength of unsoaked single fibers, but has a beneficial effect in terms of strength retention under HT testing. This beneficial effect of the coating disappears for soaked samples. The results for tows and minicomposites also indicate that for the unsoaked condition, tensile failure appears to be driven by fiber surface flaws and the presence of the monazite coatings clearly improves both RT and HT strength of fibers, tows and minicomposites. However, the beneficial effects of the coating disappear after long term exposure to HT.

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The SME Study on Competency Gaps in Manufacturing Education has catalyzed the genesis and propagation of many outstanding programs to reform and revamp manufacturing education. However, the report's impact extends beyond manufacturing education-the techniques of competency gap identification, feedback and improvement can be replicated in other technical curricula. Unfortunately, curricular-level improvements are difficult without buy-in from the administration or the entire faculty. It is far easier for an individual instructor to influence pedagogical outcomes in their own classroom than at the departmental level. The authors believe that a 'miniaturized' version of the competency gap identification technique can provide a valuable pedagogical tool to the instructor. The paper discusses a test case that has been implemented in a junior-level mechanical engineering class on manufacturing processes. By tracking typical student errors on routine assessment instruments such as homework, quizzes and tests, five major categories of competency gaps were identified-comprehension, information, writing, units usage and quantitative analysis. This information has been continuously fed back to the students and used by them to continuously improve their performance. The paper will report on outcomes of this test case and discuss its scalability to other courses.

The tensile strengths of Nextel™ 720 fibers, both bare and coated with monazite, and tows made of these fibers, were measured to study the effects of coating and thermal exposure. Close agreement was observed between the Weibull modulus obtained from the statistical fracture distribution and the modulus obtained from a study of the gage length dependence of strength. Thermal soaking for 24h at 1000, 1100 and 1200°C revealed significant differences in the behavior of coated and uncoated fibers. Uncoated fibers subjected to soaking for 24h at 1200°C retained 91% of their unsoaked strength, while similarly soaked coated fibers retained only 61%. The effect of coating reversed in the case of tows, with the presence of coating enabling higher strength retention after thermal exposure.

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