title: Microstructure and mechanical properties of large size as-cast Ti-43Al-9V-0.2Y (at.%) alloy ingot from brim to centre

authors: Kong, Fantao

subjects: Intermetallics

abstract: A Ti-43Al-9V-0.2Y (at.%) alloy ingot with the size of Ф160×400mm was prepared by vacuum arc remelting (VAR). The microstructure of the as-cast Ti-43Al-9V-0.2Y alloy was composed of B2/α₂/γ lamellar colonies and massive B2 and γ phases which were distributed along the boundaries of these lamellar colonies in the form of equiaxed grains. Based on the grain size variation along the radius direction of the ingot, the ingot could be divided into four ring regions from brim to centre. It has been understood that the grain size variation between these four regions was due to the interplay of the effects of the cooling rate and the yttrium content on solidified microstructures in these regions. Mechanical testing of the samples cut from these four regions showed that there existed a clear correlation between the yield strength and the average grain sizes of the four ring regions, which approximately conformed to a Hall-Petch relationship.

text: Microstructure and mechanical properties of large size as-cast Ti-43Al-9V-0.2Y (at.%) alloy ingot from brim to centre A Ti-43Al-9V-0.2Y (at.%) alloy ingot with the size of Ф160×400mm was prepared by vacuum arc remelting (VAR). The microstructure of the as-cast Ti-43Al-9V-0.2Y alloy was composed of B2/α₂/γ lamellar colonies and massive B2 and γ phases which were distributed along the boundaries of these lamellar colonies in the form of equiaxed grains. Based on the grain size variation along the radius direction of the ingot, the ingot could be divided into four ring regions from brim to centre. It has been understood that the grain size variation between these four regions was due to the interplay of the effects of the cooling rate and the yttrium content on solidified microstructures in these regions. Mechanical testing of the samples cut from these four regions showed that there existed a clear correlation between the yield strength and the average grain sizes of the four ring regions, which approximately conformed to a Hall-Petch relationship.

year: 2011

title: Student Teacher and Lecturer Perceptions of the Use of Asynchronous Discussion Forums, Quizzes and Uploaded Resources for Promoting Critical Thinking

authors: Mwalongo, Alcuin Ivor

subjects: Student and Lecturer Perceptions

abstract: This study examined student teacher and lecturer perceptions of the use of asynchronous discussion forums, quizzes and uploaded resources for promoting critical thinking within a pre-service teacher education programme in Tanzania. Critical thinking is necessary both in life in general, and in education in particular. Critical thinking skills and thinking dispositions help people solve their problems, make rational decisions, evaluate information, guide their beliefs and actions, and improve their reasoning skills. While critical thinking skills influence the ability to carry out a thinking task, thinking dispositions may determine which actions should be carried out, the manner in which they should be carried out, and when they should be carried out. This means that critical thinking is influenced by contextual factors such as time, place, intentions, motivations of the thinker, and subject matter under discussion. However, most of the previous studies have tended to measure the two components of critical thinking separately and use different instruments. This way of measuring critical thinking is incompatible with the current conceptualisation of critical thinking, where critical thinking is understood as a set of related cognitive skills and dispositions. Since critical thinking varies over time and in different places, to get a clearer picture of an individual’s critical thinking, both critical thinking skills and thinking dispositions need to be measured simultaneously using the same instrument in order to offset the influence of contextual factors. 
Learning management systems (LMS) have tools such as asynchronous discussion forums, and quizzes that can promote critical thinking, especially when conscious planning is considered. Since, these tools have the potential for promoting critical thinking, measuring the evidence of critical thinking manifested in those tools is important. Current instruments measuring critical thinking in tasks related to asynchronous discussion forums do not relate thinking skills such as recall, and comprehension, and dispositional factors to critical thinking. Recall, comprehension and dispositional factors need to be measured in asynchronous discussion forums because they influence critical thinking. 
This study used sociocultural theory as its theoretical framework. Employing a case study approach, 54 students and 15 lecturers from three public universities in Tanzania participated in a survey. Using sample integration, eight students and six lecturers were selected for focus group discussions and one-to-one interviews. Mixed methods research was used to collect and generate data through surveys, focus group discussions, documentary review, and researcher’s reflective journal. While quantitative data were analysed through SPSS 21, qualitative data were analysed through NVivo 10.
Results revealed similarities and differences in critical thinking between students and lecturers, pre-service and in-service student teachers, male and female students, and between younger and older lecturers. The study contributes to knowledge by developing a combined instrument for capturing critical thinking skills and thinking dispositions simultaneously. Another instrument, the RCS-CAIS model is an attempt to show the relationship between critical thinking skills and dispositional factors in tasks related to asynchronous discussion forums. The study contributes to theory by demonstrating that thinking skills are not hierarchical, but are rather overlapping, iterative and multi-directional depending on prevailing circumstances at the time of engaging in a thinking task. Pedagogical and institutional implications of the findings have been discussed. Finally, areas for further research have been suggested.

text: Student Teacher and Lecturer Perceptions of the Use of Asynchronous Discussion Forums, Quizzes and Uploaded Resources for Promoting Critical Thinking This study examined student teacher and lecturer perceptions of the use of asynchronous discussion forums, quizzes and uploaded resources for promoting critical thinking within a pre-service teacher education programme in Tanzania. Critical thinking is necessary both in life in general, and in education in particular. Critical thinking skills and thinking dispositions help people solve their problems, make rational decisions, evaluate information, guide their beliefs and actions, and improve their reasoning skills. While critical thinking skills influence the ability to carry out a thinking task, thinking dispositions may determine which actions should be carried out, the manner in which they should be carried out, and when they should be carried out. This means that critical thinking is influenced by contextual factors such as time, place, intentions, motivations of the thinker, and subject matter under discussion. However, most of the previous studies have tended to measure the two components of critical thinking separately and use different instruments. This way of measuring critical thinking is incompatible with the current conceptualisation of critical thinking, where critical thinking is understood as a set of related cognitive skills and dispositions. Since critical thinking varies over time and in different places, to get a clearer picture of an individual’s critical thinking, both critical thinking skills and thinking dispositions need to be measured simultaneously using the same instrument in order to offset the influence of contextual factors. 
Learning management systems (LMS) have tools such as asynchronous discussion forums, and quizzes that can promote critical thinking, especially when conscious planning is considered. Since, these tools have the potential for promoting critical thinking, measuring the evidence of critical thinking manifested in those tools is important. Current instruments measuring critical thinking in tasks related to asynchronous discussion forums do not relate thinking skills such as recall, and comprehension, and dispositional factors to critical thinking. Recall, comprehension and dispositional factors need to be measured in asynchronous discussion forums because they influence critical thinking. 
This study used sociocultural theory as its theoretical framework. Employing a case study approach, 54 students and 15 lecturers from three public universities in Tanzania participated in a survey. Using sample integration, eight students and six lecturers were selected for focus group discussions and one-to-one interviews. Mixed methods research was used to collect and generate data through surveys, focus group discussions, documentary review, and researcher’s reflective journal. While quantitative data were analysed through SPSS 21, qualitative data were analysed through NVivo 10.
Results revealed similarities and differences in critical thinking between students and lecturers, pre-service and in-service student teachers, male and female students, and between younger and older lecturers. The study contributes to knowledge by developing a combined instrument for capturing critical thinking skills and thinking dispositions simultaneously. Another instrument, the RCS-CAIS model is an attempt to show the relationship between critical thinking skills and dispositional factors in tasks related to asynchronous discussion forums. The study contributes to theory by demonstrating that thinking skills are not hierarchical, but are rather overlapping, iterative and multi-directional depending on prevailing circumstances at the time of engaging in a thinking task. Pedagogical and institutional implications of the findings have been discussed. Finally, areas for further research have been suggested.

year: 2014

title: What are the perceptions of Māori bilingual-educated families towards growing up and learning the Māori language?

authors: Hill, Richard Kenneth

abstract: The Māori language occupies an important place as New Zealand’s indigenous language. This is despite over a century  of attempts  to wipe it out. The revitalisation movement from the 1980s has made a significant contribution to raise its profile and ensure younger generations of primarily Māori students can grow up learning the Māori language through school. However, significant issues still exist, as low numbers of families take advantage of bilingual education options, and remain there to develop high levels of proficiency.


Attitudes of both Māori and non-Māori (Pākehā) populations towards the Māori language have been steadily improving in recent decades. There are increasing calls to make it a compulsory subject in all New Zealand schools. Whilst these are positive signs, the long term health of the Māori language is still precarious. Using the findings of recent studies into Māori bilingual school transitions, including Hill, Rameka and Skerrett (2017) and Hill (2014, 2016, 2017), this presentation seeks to unpack the perceptions of Māori students and their families from a range of programmes towards their languages (Māori and English) and their lives. The findings will illustrate that families within the Māori bilingual education context are enthusiastic about  Māori language learning and being educated bilingually. They are also resolute that bilingual education will help to prepare their children  for their world. However,  families often differ in the extent to which they commit to high immersion programmes, thus affecting the potential success of the Māori language revitalisation aim.

text: What are the perceptions of Māori bilingual-educated families towards growing up and learning the Māori language? The Māori language occupies an important place as New Zealand’s indigenous language. This is despite over a century  of attempts  to wipe it out. The revitalisation movement from the 1980s has made a significant contribution to raise its profile and ensure younger generations of primarily Māori students can grow up learning the Māori language through school. However, significant issues still exist, as low numbers of families take advantage of bilingual education options, and remain there to develop high levels of proficiency.


Attitudes of both Māori and non-Māori (Pākehā) populations towards the Māori language have been steadily improving in recent decades. There are increasing calls to make it a compulsory subject in all New Zealand schools. Whilst these are positive signs, the long term health of the Māori language is still precarious. Using the findings of recent studies into Māori bilingual school transitions, including Hill, Rameka and Skerrett (2017) and Hill (2014, 2016, 2017), this presentation seeks to unpack the perceptions of Māori students and their families from a range of programmes towards their languages (Māori and English) and their lives. The findings will illustrate that families within the Māori bilingual education context are enthusiastic about  Māori language learning and being educated bilingually. They are also resolute that bilingual education will help to prepare their children  for their world. However,  families often differ in the extent to which they commit to high immersion programmes, thus affecting the potential success of the Māori language revitalisation aim.

year: 2018