Ceramic applications in turbine engines

Development testing activities on the 1900 F-configuration ceramic parts were completed, 2070 F-configuration ceramic component rig and engine testing was initiated, and the conceptual design for the 2265 F-configuration engine was identified. Fabrication of the 2070 F-configuration ceramic parts continued, along with burner rig development testing of the 2070 F-configuration metal combustor in preparation for 1132 C (2070 F) qualification test conditions. Shakedown testing of the hot engine simulator (HES) rig was also completed in preparation for testing of a spin rig-qualified ceramic-bladed rotor assembly at 1132 C (2070 F) test conditions. Concurrently, ceramics from new sources and alternate materials continued to be evaluated, and fabrication of 2070 F-configuration ceramic component from these new sources continued. Cold spin testing of the critical 2070 F-configuration blade continued in the spin test rig to qualify a set of ceramic blades at 117% engine speed for the gasifier turbine rotor. Rig testing of the ceramic-bladed gasifier turbine rotor assembly at 108% engine speed was also performed, which resulted in the failure of one blade. The new three-piece hot seal with the nickel oxide/calcium fluoride wearface composition was qualified in the regenerator rig and introduced to engine operation wiwth marginal success

Success, Disabilities, and Adult Education: A Historical Journey

Through historical analysis, adult education is shown to perpetuate widespread social practices of oppression for learners who experience intellectual and other disabilities. A redefinition of whom and what makes a valuable contribution to society is offered; a shift to more inclusive thinking is recommended and a practical necessity due to recent federal legislation

Well-being in a biracial sample : racial identification and similarity to parents

Thesis (Ph. D.)--Boston University, 1994.It has been estimated that there are between one and ten million "biracial persons living in the United States at this time, yet a paucity of empirical data exists as to how those with mixed racial heritages manage the developmental tasks associated with identity formation. This project studies racial identification and parental similarity as they relate to psychological well-being in a non-clinical sample of biracial persons. Well-being served as the independent variable in the analyses and was assessed with the Affect Balance Scale which measures both positive and negative affective experiences in subjects' daily lives. Greater wellbeing is attributed to those for whom positive affect is not outweighed by negative affect. All subjects were adults with one black (African-American) and one white (European-American) parent. [TRUNCATED

The Bouncing Jet: A Newtonian Liquid Rebounding off a Free Surface

We find that a liquid jet can bounce off a bath of the same liquid if the bath is moving horizontally with respect to the jet. Previous observations of jets rebounding off a bath (e.g. Kaye effect) have been reported only for non-Newtonian fluids, while we observe bouncing jets in a variety of Newtonian fluids, including mineral oil poured by hand. A thin layer of air separates the bouncing jet from the bath, and the relative motion replenishes the film of air. Jets with one or two bounces are stable for a range of viscosity, jet flow rate and velocity, and bath velocity. The bouncing phenomenon exhibits hysteresis and multiple steady states.Comment: 9 pages, 7 figures. submitted to Physical Review

The Potential Impact of Plain Packaging of Cigarette Products Among Brazilian Young Women: An Experimental Study

Background: Tobacco use is responsible for 5.4 million deaths every year worldwide and is a leading cause of preventable death. The burden of these deaths is rapidly shifting to low and middle-income countries, such as Brazil. Brazil has prohibited most forms of tobacco advertising; however, the cigarette pack remains a primary source of marketing. The current study examined how tobacco packaging influences brand appeal and perceptions of health risk among young women in Brazil. Methods: A between-subjects experiment was conducted in which 640 Brazilian women aged 16–26 participated in an online survey. Participants were randomized to view 10 cigarette packages according to one of three experimental conditions: standard branded packages, the same packs without brand imagery (“plain packaging”), or the same packs without brand imagery or descriptors (e.g., flavors). Participants rated packages on perceived appeal, taste, health risk, smoothness, and smoker attributes. Finally, participants were shown a range of branded and plain packs from which they could select one as a free gift, which constituted a behavioral measure of appeal. Results: Branded packs were rated as significantly more appealing, better tasting, and smoother on the throat than plain packs. Branded packs were also associated with a greater number of positive smoker attributes including style and sophistication, and were perceived as more likely to be smoked by females than the plain packs. Removing descriptors from the plain packs further decreased the ratings of appeal, taste and smoothness, and also reduced associations with positive attributes. In the pack offer, participants were three times more likely to select branded packs than plain packs. Conclusions: Plain packaging and removal of descriptors may reduce the appeal of smoking for youth and young adults, and consequently reduce smoking susceptibility. Overall, the findings provide support for plain packaging regulations, such as those in Australia

Actual and Predicted Behavior of Large Metal Culverts

The stability of large metal culverts depends on the performance of the backfill around the pipe, which must be considered as a part of the structure when evaluating its safety. A simplified method to evaluate the current stability of such a structure on the basis of the structure\u27s shape is derived. Useful when limited amount of information is available, this method provides an economical procedure for: (1) evaluating the condition of the existing backfill and its capability to provide a safe support for the structure; (2) predicting final movements and determining if additional investigations are necessary to establish the safety of the structure; and (3) determining if measured deflections are in agreement with those predicted and, if not, determining if the safety of the structure is endangered by phenomena other than the expected behavior of surrounding soil (e.g. voids near pipe, soil erosion, non-symmetric loadings)

Harmonic moment dynamics in Laplacian growth

Harmonic moments are integrals of integer powers of z = x+iy over a domain. Here the domain is an exterior of a bubble of air growing in an oil layer between two horizontal closely spaced plates. Harmonic moments are a natural basis for such Laplacian growth phenomena because, unlike other representations, these moments linearize the zero surface tension problem (Richardson, 1972), so that all moments except the lowest one are conserved in time. For non-zero surface tension, we show that the the harmonic moments decay in time rather than exhibiting the divergences of other representations. Our laboratory observations confirm the theoretical predictions and demonstrate that an interface dynamics description in terms of harmonic moments is physically realizable and robust. In addition, by extending the theory to include surface tension, we obtain from measurements of the time evolution of the harmonic moments a value for the surface tension that is within 20% of the accepted value.Comment: 10 pages, 7 figure