title: Influence of powder forging and heat treatment conditions on the properties of the cost-effective Ti-5Al-2.5Fe alloy

authors: Bolzoni, Leandro

abstract: The Ti-5Al-2.5Fe alloy is a cheaper α+β Ti alloy with mechanical performance comparable to those of the Ti-6Al-4V alloy whose cost could be further reduced by producing it via powder metallurgy. In this study, the effect of the thermomechanical deformation temperature on the properties of the Ti-5Al-2.5Fe alloy produced from elemental powders was studied. Furthermore, the effect of the modification of the microstructure via heat treatments on the properties of the forged billets was analysed. This study demonstrates that powder forging can successfully be used to manufacture α+β Ti alloys and the selection of the forging temperature significantly affects the mechanical behaviour, where the lower the forging temperature the stronger and the less ductile the material. The post-processing via solution treatment plus aging generally improves the mechanical properties of the Ti-5Al-2.5Fe alloy, especially in terms of ductility, without compromising the strength.

text: Influence of powder forging and heat treatment conditions on the properties of the cost-effective Ti-5Al-2.5Fe alloy The Ti-5Al-2.5Fe alloy is a cheaper α+β Ti alloy with mechanical performance comparable to those of the Ti-6Al-4V alloy whose cost could be further reduced by producing it via powder metallurgy. In this study, the effect of the thermomechanical deformation temperature on the properties of the Ti-5Al-2.5Fe alloy produced from elemental powders was studied. Furthermore, the effect of the modification of the microstructure via heat treatments on the properties of the forged billets was analysed. This study demonstrates that powder forging can successfully be used to manufacture α+β Ti alloys and the selection of the forging temperature significantly affects the mechanical behaviour, where the lower the forging temperature the stronger and the less ductile the material. The post-processing via solution treatment plus aging generally improves the mechanical properties of the Ti-5Al-2.5Fe alloy, especially in terms of ductility, without compromising the strength.

year: 2023-01-01

title: An analysis of total correctness refinement models for partial relation semantics I

authors: Deutsch, Moshe

subjects: operation refinement

abstract: This is the first of a series of papers devoted to the thorough investigation of (total correctness) refinement based on an underlying partial relational model. In this paper we restrict attention to operation refinement. We explore four theories of refinement based on an underlying partial relation model for specifications, and we show that they are all equivalent. This, in particular, sheds some light on the relational completion operator (lifted-totalisation) due to Wookcock which underlines data refinement in, for example, the specification language Z. It further leads to two simple alternative models which are also equivalent to the others.

text: An analysis of total correctness refinement models for partial relation semantics I This is the first of a series of papers devoted to the thorough investigation of (total correctness) refinement based on an underlying partial relational model. In this paper we restrict attention to operation refinement. We explore four theories of refinement based on an underlying partial relation model for specifications, and we show that they are all equivalent. This, in particular, sheds some light on the relational completion operator (lifted-totalisation) due to Wookcock which underlines data refinement in, for example, the specification language Z. It further leads to two simple alternative models which are also equivalent to the others.

year: 2003

title: Testing a suicidal ideation-to-action framework among Queer and Takatāpui people in Aotearoa New Zealand: An examination of the three-step theory

authors: Schimanski, Irie

abstract: The three-step theory (3ST) of suicide is well-established in the general population and shows promise for explaining suicidal ideation among Queer samples. This study examined the applicability of the 3ST using data from 250 Queer (n = 213) and Takatāpui (n = 37) people aged 18-74 living in Aotearoa New Zealand. The analytic approach entailed hierarchical multiple regression, ANOVA, t-tests, and logistic regression. Step-one was partially supported, with discrimination and hopelessness independently associated with suicidal ideation, but not their interaction. Step-two was fully supported, showing social support associated with lower suicidal ideation when social support exceeded discrimination, compared with the inverse. Full support for step-three was observed, finding higher self-harm among participants with histories of attempted suicide than those who had never attempted. An adapted version of the 3ST for Queer and Takatāpui people is presented, offering novel approaches to testing the ideation-to-action framework with these communities.

text: Testing a suicidal ideation-to-action framework among Queer and Takatāpui people in Aotearoa New Zealand: An examination of the three-step theory The three-step theory (3ST) of suicide is well-established in the general population and shows promise for explaining suicidal ideation among Queer samples. This study examined the applicability of the 3ST using data from 250 Queer (n = 213) and Takatāpui (n = 37) people aged 18-74 living in Aotearoa New Zealand. The analytic approach entailed hierarchical multiple regression, ANOVA, t-tests, and logistic regression. Step-one was partially supported, with discrimination and hopelessness independently associated with suicidal ideation, but not their interaction. Step-two was fully supported, showing social support associated with lower suicidal ideation when social support exceeded discrimination, compared with the inverse. Full support for step-three was observed, finding higher self-harm among participants with histories of attempted suicide than those who had never attempted. An adapted version of the 3ST for Queer and Takatāpui people is presented, offering novel approaches to testing the ideation-to-action framework with these communities.

year: 2025-08-01