Milling with ceramic inserts of austempered ductile iron (ADI): process conditions and performance.

In the work here presented, the high performance of ceramic insert tools in milling of ADI 1000 iron casting is analyzed. Austempered ductile irons (ADI) are ductile iron castings with strength and mechanical properties enhanced after specific heat treatment, achieving 1000 MPa or even more. Sintered carbide tools are state of the art in many industrial applications, including iron casting machining, but ceramic inserts are a feasible and promising option since cutting speed can be improved by 5 or even 10 times. A complete testing campaign was performed, starting with coated sintered carbides and aiming at the use of whisker reinforced Al2O3 ceramics and Si3N4 tools. The two most important conclusions are as follows: firstly, that the milling type so-called up-milling (or conventional) is more recommended than down-milling, also known as climb milling, and secondly, that dry machining enhances ceramics performance in comparison with using emulsion coolants (oil in water). Finally, results regarding economic aspects were analyzed based on the tools cost-performance ratio.

Memory Age-based Stereotype Threat: Role of Locus of Control and Anxiety.

Background: Age-related stereotype threat impacts episodic memory performance. This study compared the predictors of memory performance in older adults with and without exposure to age-related stereotype threat, hypothesizing that activating the stereotype threat modulates the relative weight of metamemory predictors of memory performance.Methods: Participants were 80 older adults (aged 60-84 years) divided into two groups, one with stereotype threat activation and one without; both groups performed an episodic memory task. To activate the stereotype threat, the memory component of the task was emphasized in the instruction given to the threatened group. Both groups also completed two scales of the MIA questionnaire (locus of control and anxiety) to identify potential predictors of memory performance.Results: Results indicated that the non-threatened group performed better than the threatened group on the episodic memory task. They also indicated that factors predicting episodic memory performance varied according to the group. In the non-threatened group, both control and anxiety were involved in memory performance and interacted whereas in the threatened group only anxiety was involved.Conclusion: This study confirms that aging stereotype threat impairs episodic memory performance; it also suggests that stereotype threat disrupts mechanisms underlying memory performance abolishing the role of control over memory regardless of the level of anxiety.