title: Microstructural evolution during mechanical milling of Ti/Al powder mixture and production of intermetallic TiAl cathode target

authors: Gabbitas, Brian

subjects: titanium aluminides

abstract: Titanium aluminides are of great technological interest because of their attractive mechanical properties. Mechanical milling/alloying is a promising powder metallurgical technique, which can achieve ultrafine, uniform and manipulable microstructures. In this study, we employed a recently revisited discus mill to produce a composite Ti– (50–57) at.%Al powder feedstock, which is suitable for hot consolidation to produce bulk cathode targets for physical vapour deposition (PVD) coatings. The effects of milling time, quantity of process control agent (PCA) and discus-topowder weight ratio (DPR) on the microstructure evolution of the attendant Ti/Al composite powder were investigated in detail. It was found that to produce Ti/Al composite powders with a fine particle size and a uniform microstructure, the practicable processing parameters should be 2 or 3% isopropanol addition as PCA, 12 h of milling time and at least 13:1 DPR weight ratio. Cathode targets were produced by hot isostatic pressing (HIPing) the as-milled powders. The targets were then used to produce a PVD TiAlN coating which had an average microhardness of 2400 HV.

text: Microstructural evolution during mechanical milling of Ti/Al powder mixture and production of intermetallic TiAl cathode target Titanium aluminides are of great technological interest because of their attractive mechanical properties. Mechanical milling/alloying is a promising powder metallurgical technique, which can achieve ultrafine, uniform and manipulable microstructures. In this study, we employed a recently revisited discus mill to produce a composite Ti– (50–57) at.%Al powder feedstock, which is suitable for hot consolidation to produce bulk cathode targets for physical vapour deposition (PVD) coatings. The effects of milling time, quantity of process control agent (PCA) and discus-topowder weight ratio (DPR) on the microstructure evolution of the attendant Ti/Al composite powder were investigated in detail. It was found that to produce Ti/Al composite powders with a fine particle size and a uniform microstructure, the practicable processing parameters should be 2 or 3% isopropanol addition as PCA, 12 h of milling time and at least 13:1 DPR weight ratio. Cathode targets were produced by hot isostatic pressing (HIPing) the as-milled powders. The targets were then used to produce a PVD TiAlN coating which had an average microhardness of 2400 HV.

year: 2011

title: Politeness and face in digitally reconfigured e-learning spaces

authors: Locke, Terry

subjects: online learning environments

abstract: This paper has two starting points. The first is a theorization about the way in which “rhetorical space” is reshaped in asynchronous, online, learning environments. In particular, an asynchronous bulletin- board (ABB) discussion offers both opportunities and constraints for teaching and learning. The learning that occurs will be affected by the affordances implicit in the design of the conversational space itself and the communicative practices engaged in by both teachers and students. The second starting point is a small case study, utilizing action research and discourse analytical strategies, whose research participants were the author and students involved in “delivering” and “receiving” an online education course at post-graduate level using asynchronous discussion. The course, taught in English, had a mix of Chinese students (for whom English was an additional language) and native English speakers. The paper will report on students’ perceptions of what worked for them and what didn’t in respect of this elearning environment. It will also use concepts such as politeness, face and positioning to analyse aspects of the participants’ communicative practices and will draw conclusions from these in respect of how successful learning can occur in elearning environments with multicultural and multilingual students. It will make connections between the findings of this case study and other research on asynchronous, web-based learning and will makes some suggestions about what is needed in respect of the future research agenda.

text: Politeness and face in digitally reconfigured e-learning spaces This paper has two starting points. The first is a theorization about the way in which “rhetorical space” is reshaped in asynchronous, online, learning environments. In particular, an asynchronous bulletin- board (ABB) discussion offers both opportunities and constraints for teaching and learning. The learning that occurs will be affected by the affordances implicit in the design of the conversational space itself and the communicative practices engaged in by both teachers and students. The second starting point is a small case study, utilizing action research and discourse analytical strategies, whose research participants were the author and students involved in “delivering” and “receiving” an online education course at post-graduate level using asynchronous discussion. The course, taught in English, had a mix of Chinese students (for whom English was an additional language) and native English speakers. The paper will report on students’ perceptions of what worked for them and what didn’t in respect of this elearning environment. It will also use concepts such as politeness, face and positioning to analyse aspects of the participants’ communicative practices and will draw conclusions from these in respect of how successful learning can occur in elearning environments with multicultural and multilingual students. It will make connections between the findings of this case study and other research on asynchronous, web-based learning and will makes some suggestions about what is needed in respect of the future research agenda.

year: 2006

title: He maimoa i ngā whakatupuranga anamata: Ko te mātauranga taketake o ngā tūpuna me te whakarea tamariki

authors: Greensill, Hineitimoana

subjects: Poipoi tamariki

abstract: Kua āraua ki roto i te reo me ngā pūnaha mātauranga o ngā iwi taketake, ko ngā uara, ko ngā whakapono me ngā rapunga whakaaro e toko ake nei i tērā iwi. Kia whakahoropakitia tēnei ki roto o Aotearoa me Hawai‘i, i te whakaekenga o ō tātou kāinga tupu e ngā taua a te Pākehā me ngā tāmi o ngā tikanga whakawhenumi a te Kāwanantanga o muri, i tauwhatia ai te tuku o te reo Māori me te ‘ōlelo (reo) o Hawai‘i i waenga i ngā whakatupuranga, waihoki ko ngā māramatanga pūmau o roto i ngā reo i tauwhatia ai (Walker, 2004; Blaisdell & Mokuau, 1991). Ahakoa ēnei tauwhatinga, ka pupuri tonu tātou ki ngā karere i mau rā i te reo i roto i ngā ngā pātaka mātauranga a te Māori me nā kānaka (ngā tāngata) o Hawai‘i. Ko te mātauranga taketake, ngā kōrero o nehe me ngā ariā e āraua nei ki ngā tuhituhinga-ā-waha huhua, tae atu ki ngā whakataukī, ngā ‘ōlelo no‘eau, me ngā kīanga rongonui i tāngia hoki ki te pepa (Pukui, 1983). Ko te ia o ēnei momo kōrero tuku-iho taketake nei kei te kōrerotia i roto i ngā whakataukī me ngā ‘ōlelo no‘eau, he mea whakaara anō tēnei mātauranga ki ngā kaupapa whakaora reo ki Aotearoa me Hawai‘i. He momo mātauranga ēnei hei whakaara i a tātou kia mārama rawa ki ngā kano tirohanga o ō tātou tūpuna ki tō rātou ao, waihoki ko ngā hononga maha e paihere nei i a tātou ki ō tātou whanaunga.

Hei whāinga matua e āta arohaehae ana tēnei pepa i ngā momo tuhituhinga-ā-waha nei, arā ko te ‘ōlelo no‘eau me te whakataukī, kia tīroua ake ngā karere e hāngai ana ki ngā tamariki a te Māori rātou ko ngā kānaka o Hawai‘i me ngā pānga ki ngā mahi whakatupu tamariki o mua. Ka toro tēnei tuhinga ki te whakataukī me te ‘ōlelo no‘eau ki te whakapuaki i te mātauranga i mahue mai i ngā tūpuna hei rei arataki mā tātou ngā iwi taketake me ō tātou wheako tonu o nāianei.

text: He maimoa i ngā whakatupuranga anamata: Ko te mātauranga taketake o ngā tūpuna me te whakarea tamariki Kua āraua ki roto i te reo me ngā pūnaha mātauranga o ngā iwi taketake, ko ngā uara, ko ngā whakapono me ngā rapunga whakaaro e toko ake nei i tērā iwi. Kia whakahoropakitia tēnei ki roto o Aotearoa me Hawai‘i, i te whakaekenga o ō tātou kāinga tupu e ngā taua a te Pākehā me ngā tāmi o ngā tikanga whakawhenumi a te Kāwanantanga o muri, i tauwhatia ai te tuku o te reo Māori me te ‘ōlelo (reo) o Hawai‘i i waenga i ngā whakatupuranga, waihoki ko ngā māramatanga pūmau o roto i ngā reo i tauwhatia ai (Walker, 2004; Blaisdell & Mokuau, 1991). Ahakoa ēnei tauwhatinga, ka pupuri tonu tātou ki ngā karere i mau rā i te reo i roto i ngā ngā pātaka mātauranga a te Māori me nā kānaka (ngā tāngata) o Hawai‘i. Ko te mātauranga taketake, ngā kōrero o nehe me ngā ariā e āraua nei ki ngā tuhituhinga-ā-waha huhua, tae atu ki ngā whakataukī, ngā ‘ōlelo no‘eau, me ngā kīanga rongonui i tāngia hoki ki te pepa (Pukui, 1983). Ko te ia o ēnei momo kōrero tuku-iho taketake nei kei te kōrerotia i roto i ngā whakataukī me ngā ‘ōlelo no‘eau, he mea whakaara anō tēnei mātauranga ki ngā kaupapa whakaora reo ki Aotearoa me Hawai‘i. He momo mātauranga ēnei hei whakaara i a tātou kia mārama rawa ki ngā kano tirohanga o ō tātou tūpuna ki tō rātou ao, waihoki ko ngā hononga maha e paihere nei i a tātou ki ō tātou whanaunga.

Hei whāinga matua e āta arohaehae ana tēnei pepa i ngā momo tuhituhinga-ā-waha nei, arā ko te ‘ōlelo no‘eau me te whakataukī, kia tīroua ake ngā karere e hāngai ana ki ngā tamariki a te Māori rātou ko ngā kānaka o Hawai‘i me ngā pānga ki ngā mahi whakatupu tamariki o mua. Ka toro tēnei tuhinga ki te whakataukī me te ‘ōlelo no‘eau ki te whakapuaki i te mātauranga i mahue mai i ngā tūpuna hei rei arataki mā tātou ngā iwi taketake me ō tātou wheako tonu o nāianei.

year: 2017