title: Nb-based heterogeneous nuclei for enhanced α-Mg nucleation in Mg(-Al) alloys

authors: Bolzoni, Leandro

subjects: Cast

abstract: The effect of the introduction of in-situ formed Nb-based compounds on Al-including Mg alloys has been investigated. It is found that grain refinement is consistently achieved. Nb-based intermetallic particles are responsible of the effective heterogeneous nucleation of Al-including Mg alloys. The refining mechanism is discussed on the base of crystallography.

text: Nb-based heterogeneous nuclei for enhanced α-Mg nucleation in Mg(-Al) alloys The effect of the introduction of in-situ formed Nb-based compounds on Al-including Mg alloys has been investigated. It is found that grain refinement is consistently achieved. Nb-based intermetallic particles are responsible of the effective heterogeneous nucleation of Al-including Mg alloys. The refining mechanism is discussed on the base of crystallography.

year: 2016-04-15

title: Stability in the South Pacific surface marine ¹⁴C reservoir over the last 750 years. Evidence from American Samoa, the southern Cook Islands and the Marquesas

authors: Petchey, Fiona

subjects: ΔR

abstract: Although minor climatic and sea-level changes have been documented for the South Pacific during the late Holocene, our understanding of the consequent impact of these changes on the marine ¹⁴C reservoir, and therefore the ¹⁴C content of shellfish, is limited. Ultimately, this has implications for documenting the chronology of human movement and adaptation in this region. In this paper we compare marine reservoir (ΔR) data obtained from tightly controlled archaeological proveniences with known-age, pre-AD 1950 shells from the southern Cook Islands, American Samoa, and Marquesas Islands. Results indicate that there has been no significant change in the near-shore marine reservoir in these three locations over the last ca. 750 years. Furthermore, known-age, pre-AD 1950 shell samples provide more precise ΔR values for use in sample calibration than archaeological paired shell/charcoal samples. This is attributed in part to the limitations of assigning provenance and age to material from archaeological sites. On the basis of these results we conclude that the known-age, pre-AD 1950 shell derived ΔR values can be used to calibrate shell ¹⁴C results from deposits of late Holocene age.

text: Stability in the South Pacific surface marine ¹⁴C reservoir over the last 750 years. Evidence from American Samoa, the southern Cook Islands and the Marquesas Although minor climatic and sea-level changes have been documented for the South Pacific during the late Holocene, our understanding of the consequent impact of these changes on the marine ¹⁴C reservoir, and therefore the ¹⁴C content of shellfish, is limited. Ultimately, this has implications for documenting the chronology of human movement and adaptation in this region. In this paper we compare marine reservoir (ΔR) data obtained from tightly controlled archaeological proveniences with known-age, pre-AD 1950 shells from the southern Cook Islands, American Samoa, and Marquesas Islands. Results indicate that there has been no significant change in the near-shore marine reservoir in these three locations over the last ca. 750 years. Furthermore, known-age, pre-AD 1950 shell samples provide more precise ΔR values for use in sample calibration than archaeological paired shell/charcoal samples. This is attributed in part to the limitations of assigning provenance and age to material from archaeological sites. On the basis of these results we conclude that the known-age, pre-AD 1950 shell derived ΔR values can be used to calibrate shell ¹⁴C results from deposits of late Holocene age.

year: 2009

title: "Ko au te whenua, ko te whenua ko au:" A Māori housing development process

authors: Fletcher, Marcus Anzac Kewene

subjects: Māori

abstract: Tangata whenua (People of the land/Indigenous people of Aotearoa) are being recognised as emerging property and land developers in Aotearoa New Zealand (hereafter, Aotearoa). Literature and practice demonstrates how Māori are developing housing in different ways than traditional developers, supporting the wellbeing of whānau (families), hapū (sub-tribes) and iwi (tribes), while contributing to addressing the national housing crisis. The distinctiveness of these approaches are important to understand if we want to deepen our knowledge of urban development and the modelling of housing markets in Aotearoa. This thesis aims to reveal, codify and examine Māori decision-making processes relating to how and why we develop housing in Aotearoa and the values and principles that inform these approaches. Utilising Kaupapa Māori Theory and taking an insider/whānaunga (relatives) approach to the research, four whakawhiti kōrero sessions with Waikato whānau and kaimahi (workers) were undertaken to better understand how and why Māori develop housing and the processes and rationalities at play. The thesis has three contributions for academia, environmental planning and the housing sector in Aotearoa: insights into the values and rationalities that influence Māori urban development; the introduction of a Māori housing development framework; and insights into how the framework may be utilised to contribute towards more accurate and sophisticated agent-based modelling (ABM) or urban growth modelling.  

The findings and discussion identified six prominent values that Māori utilise to develop housing: kaitiakitanga, manaakitanga, orangatanga, whānaungatanga, ūkaipōtanga and rangatiratanga. Being rooted in Māori knowledge and epistemology essentially demands differing rationalities for when Māori undertake housing development, which are placed within an overarching framework. The framework represents a new tool to disrupt the current understanding of ‘developers’ as a single entity with a defined pathway that influences all development behaviour. Moreover, it demonstrates how whānau, hapū and iwi draw on the established learning and guidance of our tūpuna (ancestors) and the strides taken to reclaim tino rangatiratanga (self-determination). The thesis argues that academics, environmental practitioners and the housing sector should re-examine their understanding of developers in Aotearoa to become more pluralistic, which may present new challenges and opportunities for ABM and urban growth modelling. This framework argues some aspects may have potential to be incorporated into these technical analyses, while other aspects should be considered in the context of Māori and Indigenous Data Sovereignty to protect the contributions and mana of the participants within this thesis, or resist the ability to be captured altogether.

text: "Ko au te whenua, ko te whenua ko au:" A Māori housing development process Tangata whenua (People of the land/Indigenous people of Aotearoa) are being recognised as emerging property and land developers in Aotearoa New Zealand (hereafter, Aotearoa). Literature and practice demonstrates how Māori are developing housing in different ways than traditional developers, supporting the wellbeing of whānau (families), hapū (sub-tribes) and iwi (tribes), while contributing to addressing the national housing crisis. The distinctiveness of these approaches are important to understand if we want to deepen our knowledge of urban development and the modelling of housing markets in Aotearoa. This thesis aims to reveal, codify and examine Māori decision-making processes relating to how and why we develop housing in Aotearoa and the values and principles that inform these approaches. Utilising Kaupapa Māori Theory and taking an insider/whānaunga (relatives) approach to the research, four whakawhiti kōrero sessions with Waikato whānau and kaimahi (workers) were undertaken to better understand how and why Māori develop housing and the processes and rationalities at play. The thesis has three contributions for academia, environmental planning and the housing sector in Aotearoa: insights into the values and rationalities that influence Māori urban development; the introduction of a Māori housing development framework; and insights into how the framework may be utilised to contribute towards more accurate and sophisticated agent-based modelling (ABM) or urban growth modelling.  

The findings and discussion identified six prominent values that Māori utilise to develop housing: kaitiakitanga, manaakitanga, orangatanga, whānaungatanga, ūkaipōtanga and rangatiratanga. Being rooted in Māori knowledge and epistemology essentially demands differing rationalities for when Māori undertake housing development, which are placed within an overarching framework. The framework represents a new tool to disrupt the current understanding of ‘developers’ as a single entity with a defined pathway that influences all development behaviour. Moreover, it demonstrates how whānau, hapū and iwi draw on the established learning and guidance of our tūpuna (ancestors) and the strides taken to reclaim tino rangatiratanga (self-determination). The thesis argues that academics, environmental practitioners and the housing sector should re-examine their understanding of developers in Aotearoa to become more pluralistic, which may present new challenges and opportunities for ABM and urban growth modelling. This framework argues some aspects may have potential to be incorporated into these technical analyses, while other aspects should be considered in the context of Māori and Indigenous Data Sovereignty to protect the contributions and mana of the participants within this thesis, or resist the ability to be captured altogether.

year: 2025