Densification and Deformation Behavior of Sintered P/M Zinc-Zinc Oxide Composite during Cold Upsetting
Studies were carried out to evaluate the initially preformed density and initial aspect ratio on the densification behavior of sintered Zinc and Zinc Oxide composite. The preform possessed 0.85 is the initial density. Aspect ratio for three different oxidizing temperatures (at 150°C, 200°C and 250°C) varied from 0.4 to 0.85. Properties of Zinc-Zinc Oxide composites with respect to linear strain, lateral strain and true stress were evaluated and plotted. Studies revealed that higher stress and higher strain values are obtained in composite when compared to the Zinc dust. The composite of Zinc-Zinc Oxide obtained at 150 o C possessed the highest stress and strain when compared to the composites obtained at others two temperatures (200 o C and 250 o C).
Kinetics of boehmite precipitation from supersaturated sodium aluminate solutions
Abstract This work presents the effect of the most important parameters, the precipitation temperature, the sodium hydroxide concentration and the initial seed ratio (SR) in the solution, on the boehmite precipitation from supersaturated sodium aluminate solutions. A kinetic model that describes the experimental data was developed. According to that model, boehmite precipitation follows second order reaction kinetics and has activation energy of 89 kJ/mol. The orders of the precipitation reaction with respect to the initial sodium hydroxide concentration and the initial seed ratio are estimated to be −1.8 and 0.54, respectively. The most important result is that the boehmite precipitation reaches an apparent equilibrium stage at which the alumina concentration is much higher compared to the value of the boehmite solubility under the same experimental conditions. The results reveal that the boehmite precipitation is a self-decelerated process and the observed kinetic inhibitions are related to the sodium hydroxide concentration in the supersaturated solution. Finally, a mechanistic interpretation of the experimental data is presented based on the concept of the surface precipitation of boehmite on the active sites of the boehmite seed.
Negotiating the cultural and economic outcomes of sport heritage attractions: the case of the National Baseball Hall of Fame
ABSTRACT Contemporary museums must balance their roles as commercial entities and repositories of various, and often dissonant, heritages and histories. Sports museums in particular often have clear commercial and nostalgic aims, particularly through tourist visitation, though the extent to which they represent more challenging narratives remains unclear. This paper examines how one of the most famous sports museums in the world, the National Baseball Hall of Fame (NBHF) in Cooperstown, New York, balances its dual role as tourist attraction and repository of baseball's sometimes checkered past. It was found that different sections of the museum provide greater or lesser degrees of engagement with more controversial issues, although the commercial outputs and appeal of the museum remains clear throughout. Utlimately, the NBHF demonstrates that balancing veneration and critique in collections can be commercially prosperous, and can provide a template for other sport and popular culture museums who may be wary of incorporating more challenging narratives in their exhibits. Furthermore, the symbiotic relationship between the Hall of Fame and the village of Cooperstown, particularly in creating and maintaining cultural and economic outputs, requires further exploration.