title: Microstructure and magnetic properties of nanostructured Al₂O₃-20vol%Fe₇₀Co₃₀ composite prepared by high energy mechanical milling

authors: Yusop, Masleeyati

subjects: ceramic-alloy composite

abstract: Al₂o₃-20vol%Fe₇₀Co₃₀ composite powders have been prepared by high energy ball milling a mixture of Al₂O₃ powder and Fe₇₀Co₃₀ alloy powder. The Fe₇₀Co₃₀ alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe₇₀Co₃₀  alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al₂O₃  matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.

text: Microstructure and magnetic properties of nanostructured Al₂O₃-20vol%Fe₇₀Co₃₀ composite prepared by high energy mechanical milling Al₂o₃-20vol%Fe₇₀Co₃₀ composite powders have been prepared by high energy ball milling a mixture of Al₂O₃ powder and Fe₇₀Co₃₀ alloy powder. The Fe₇₀Co₃₀ alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe₇₀Co₃₀  alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al₂O₃  matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.

year: 2009

title: Language use and the instructional strategies of Grade 3 teachers to support 'bridging' in Papua New Guinea

authors: Franken, Margaret

subjects: multilingual education

abstract: For over a decade, the Department of Education in Papua New Guinea (PNG) has adopted vernacular education as a way of ensuring that the educational experiences of children in schools draw on the cultural and linguistic knowledge they bring to the classroom. In PNG, there are many potential vernaculars - apart from the local languages, there are Tok Pisin and Hiri Motu. The policy advocates 'bridging' as an instructional strategy. While the term is used extensively by teachers, it is unclear what teachers think it entails and how they enact bridging. This small-scale exploratory study documents the views of a group of Grade 3 teachers in the East New Britain region and provides observations of their bridging strategies. While the teachers are not particularly supportive of vernacular education, they report on and use instructional strategies that include translation, metalinguistic comparison, contrast and elaboration. The teachers make much use of elicitation to encourage children to articulate their understanding of English, and they demonstrate flexible and dynamic use of languages in their classrooms. The fact that the study recorded no use of the local languages suggests that systematic follow-up of policy in practice is much needed, together with more in-depth research.

text: Language use and the instructional strategies of Grade 3 teachers to support 'bridging' in Papua New Guinea For over a decade, the Department of Education in Papua New Guinea (PNG) has adopted vernacular education as a way of ensuring that the educational experiences of children in schools draw on the cultural and linguistic knowledge they bring to the classroom. In PNG, there are many potential vernaculars - apart from the local languages, there are Tok Pisin and Hiri Motu. The policy advocates 'bridging' as an instructional strategy. While the term is used extensively by teachers, it is unclear what teachers think it entails and how they enact bridging. This small-scale exploratory study documents the views of a group of Grade 3 teachers in the East New Britain region and provides observations of their bridging strategies. While the teachers are not particularly supportive of vernacular education, they report on and use instructional strategies that include translation, metalinguistic comparison, contrast and elaboration. The teachers make much use of elicitation to encourage children to articulate their understanding of English, and they demonstrate flexible and dynamic use of languages in their classrooms. The fact that the study recorded no use of the local languages suggests that systematic follow-up of policy in practice is much needed, together with more in-depth research.

year: 2011

title: Māori cultural definitions of sexual violence.

authors: Pihama, Leonie

abstract: Exploring definitions of sexual violence in Aotearoa highlights that on the whole such definitions are located within dominant Pākehā frameworks that do not provide adequately for understanding the context of sexual violence for Māori. As such Māori working in the area of healing the trauma of sexual violence have been developing frameworks which are enabling of culturally defined understandings and traditional knowledge as a basis by which to understand sexual violence in Aotearoa. Informed by te reo and tikanga Māori (Māori language and culture) Māori healers, social workers and health providers have moved beyond western definitions and have highlighted the link between acts of sexual violence and the violence of colonial invasion. This article explores Māori perspectives of the origins and impacts of sexual violence for Māori and advocates for Kaupapa Māori and decolonising approaches to be more fully supported and engaged in dealing with these issues within our communities.

text: Māori cultural definitions of sexual violence. Exploring definitions of sexual violence in Aotearoa highlights that on the whole such definitions are located within dominant Pākehā frameworks that do not provide adequately for understanding the context of sexual violence for Māori. As such Māori working in the area of healing the trauma of sexual violence have been developing frameworks which are enabling of culturally defined understandings and traditional knowledge as a basis by which to understand sexual violence in Aotearoa. Informed by te reo and tikanga Māori (Māori language and culture) Māori healers, social workers and health providers have moved beyond western definitions and have highlighted the link between acts of sexual violence and the violence of colonial invasion. This article explores Māori perspectives of the origins and impacts of sexual violence for Māori and advocates for Kaupapa Māori and decolonising approaches to be more fully supported and engaged in dealing with these issues within our communities.

year: 2016