title: Metal Injection Moulding of High Nb-Containing TiAl Alloy and Its Oxidation Behaviour at 900°C

authors: Liu, Chengcheng

subjects: high Nb-containing TiAl alloy

abstract: High Nb-containing TiAl alloy with a nominal composition of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y (at %) was fabricated by metal injection moulding (MIM) technology with an improved wax-based binder. The critical powder loading and feedstock rheological behaviour were determined. The influence of sintering temperature on microstructures and mechanical properties of the sintered samples and their oxidation behaviour were also investigated. Results showed that a feedstock, with a powder loading of 68 vol % and good flowability, could be obtained by using the improved binder, and oxygen pick-up was lower than that of the sample prepared by using a traditional binder. The ultimate tensile strength (UTS) and plastic elongation of the sample sintered at 1480 °C for 2 h were 412 MPa and 0.33%, at room temperature, respectively. The 1480 °C-sintered sample consisted of γ/α2 lamellar microstructure with the average colony size of about 70 µm, and its porosity was about 4%. The sintered alloy showed better oxidation resistance than that of the cast alloy counterpart.

text: Metal Injection Moulding of High Nb-Containing TiAl Alloy and Its Oxidation Behaviour at 900°C High Nb-containing TiAl alloy with a nominal composition of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y (at %) was fabricated by metal injection moulding (MIM) technology with an improved wax-based binder. The critical powder loading and feedstock rheological behaviour were determined. The influence of sintering temperature on microstructures and mechanical properties of the sintered samples and their oxidation behaviour were also investigated. Results showed that a feedstock, with a powder loading of 68 vol % and good flowability, could be obtained by using the improved binder, and oxygen pick-up was lower than that of the sample prepared by using a traditional binder. The ultimate tensile strength (UTS) and plastic elongation of the sample sintered at 1480 °C for 2 h were 412 MPa and 0.33%, at room temperature, respectively. The 1480 °C-sintered sample consisted of γ/α2 lamellar microstructure with the average colony size of about 70 µm, and its porosity was about 4%. The sintered alloy showed better oxidation resistance than that of the cast alloy counterpart.

year: 2018

title: A Coloured Petri Net approach to model and analyze safety-critical interactive systems

authors: Jaidka, Sapna

subjects: Science & Technology

abstract: To gain confidence in safety-critical interactive systems, formal modelling and analysis plays a vital role. The aim of this paper is to use Coloured Petri Nets to model and analyze safety-critical interactive systems. We present a technique to construct a single Coloured Petri Net model of the user interface, interaction and functionality of safety-critical interactive systems and then analyze the achieved Coloured Petri Net model using a state space analysis method. There are several reasons for using Coloured Petri Nets. Coloured Petri Nets provides a graphical representation and hierarchical structuring mechanism, and a state space verification technique, which allows querying the state space to investigate behaviours of a system. There are several tools that supports Coloured Petri Nets including the CPN Tool which helps in building CPN models and allows simulation and analysis using state spaces. The technique to model and analyze safety-critical interactive systems is illustrated using a simplified infusion pump example.

text: A Coloured Petri Net approach to model and analyze safety-critical interactive systems To gain confidence in safety-critical interactive systems, formal modelling and analysis plays a vital role. The aim of this paper is to use Coloured Petri Nets to model and analyze safety-critical interactive systems. We present a technique to construct a single Coloured Petri Net model of the user interface, interaction and functionality of safety-critical interactive systems and then analyze the achieved Coloured Petri Net model using a state space analysis method. There are several reasons for using Coloured Petri Nets. Coloured Petri Nets provides a graphical representation and hierarchical structuring mechanism, and a state space verification technique, which allows querying the state space to investigate behaviours of a system. There are several tools that supports Coloured Petri Nets including the CPN Tool which helps in building CPN models and allows simulation and analysis using state spaces. The technique to model and analyze safety-critical interactive systems is illustrated using a simplified infusion pump example.

year: 2019

title: Listening to the Winds of Change: Assessing culturally responsive and relational pedagogy

authors: Thin-Rabb, Polly

subjects: Culturally responsive and relational pedagogy

abstract: This thesis examines how the Rongohia te Hau tools were used to capture a snapshot of the extent that culturally responsive and relational pedagogies were occurring within classrooms in two English-medium secondary schools in Aotearoa, New Zealand. In this study, school leaders used Rongohia te Hau to measure changes in the educational experiences of Māori learners over twelve to eighteen-months, to prioritise next steps in addressing the educational inequities that were evident. 

With the contribution of teachers, leaders and kaitoro (Kia Eke Panuku facilitators), this research investigates the purpose and place of Rongohia te Hau within the Kia Eke Panuku professional learning and development context. It also presents and discusses the pedagogical shifts that occurred in these two schools over the period of this research, as evidenced by quantitative and qualitative Rongohia te Hau data. Furthermore, the learning implications that arose out of this research are analysed to help generate new questions and considerations, to enable continuing conversations for these schools, other schools, professional learning and development providers and researchers.

text: Listening to the Winds of Change: Assessing culturally responsive and relational pedagogy This thesis examines how the Rongohia te Hau tools were used to capture a snapshot of the extent that culturally responsive and relational pedagogies were occurring within classrooms in two English-medium secondary schools in Aotearoa, New Zealand. In this study, school leaders used Rongohia te Hau to measure changes in the educational experiences of Māori learners over twelve to eighteen-months, to prioritise next steps in addressing the educational inequities that were evident. 

With the contribution of teachers, leaders and kaitoro (Kia Eke Panuku facilitators), this research investigates the purpose and place of Rongohia te Hau within the Kia Eke Panuku professional learning and development context. It also presents and discusses the pedagogical shifts that occurred in these two schools over the period of this research, as evidenced by quantitative and qualitative Rongohia te Hau data. Furthermore, the learning implications that arose out of this research are analysed to help generate new questions and considerations, to enable continuing conversations for these schools, other schools, professional learning and development providers and researchers.

year: 2017