title: Study of biomorphic calcium deficient hydroxyapatite fibres derived from a natural Harakeke (Phormium Tenax) leaf fibre template.

authors: Siddiqui, Humair Ahmed

subjects: Harakeke/Flax

abstract: The complex structure of natural bio-organic matter has inspired scientists to utilise these as templates to design "biomorphic materials", which retain the intricate architecture of the materials while acting as a useful bioactive material. Biomorphic hydroxyapatite-based fibres were synthesised using Harakeke leaf fibre as a template, which constitutes a powerful method for manufacturing bioactive ceramic fibres. Furthermore, in creating the hydroxyapatite-based fibres, a natural source of calcium and phosphate ions (from bovine bone) was utilised to create the digest solution in which the leaf fibres were immersed prior to their calcination to form the inorganic fibres. Chemical, thermogravimetric and microscopic characterisation confirmed that the final product was able to successfully replicate the shape of the fibres and furthermore be transformed into calcium deficient, bone-like hydroxyapatite.

text: Study of biomorphic calcium deficient hydroxyapatite fibres derived from a natural Harakeke (Phormium Tenax) leaf fibre template. The complex structure of natural bio-organic matter has inspired scientists to utilise these as templates to design "biomorphic materials", which retain the intricate architecture of the materials while acting as a useful bioactive material. Biomorphic hydroxyapatite-based fibres were synthesised using Harakeke leaf fibre as a template, which constitutes a powerful method for manufacturing bioactive ceramic fibres. Furthermore, in creating the hydroxyapatite-based fibres, a natural source of calcium and phosphate ions (from bovine bone) was utilised to create the digest solution in which the leaf fibres were immersed prior to their calcination to form the inorganic fibres. Chemical, thermogravimetric and microscopic characterisation confirmed that the final product was able to successfully replicate the shape of the fibres and furthermore be transformed into calcium deficient, bone-like hydroxyapatite.

year: 2020

title: Performance and applications of Gallium-Nitride Monolithic Microwave Integrated Circuits (GaN MMICs)

authors: Scott, Jonathan B.

subjects: Gallium Nitride

abstract: The evolution of wide-bandgap semiconductor transistor technology is placed in historical context with other active device technologies. The relative rapidity of GaN transistor development is noted and is attributed to the great parallel activity in the lighting sector and the historical experience and business model from the III-V compound semiconductor sector. The physical performance expectations for wide-bandgap technologies such as Gallium-Nitride Field-E®ect Transistors (GaN FETs) are reviewed. We present some device characteristics.
Challenges met in characterising, and prospects for modeling GaN FETs are described. Reliability is identified as the final remaining hurdle facing would-be foundries. Evolutionary and unsurprising applications as well as novel and revolutionary applications are suggested. Novel applications include wholly monolithic switchmode power supplies, simplified tools for ablation and diathermy in tissue, and very wide dynamic range circuits for audio or low phase noise signal generation. We conclude that now is the time to embark on circuit design of
MMICs in wide-bandgap technology. The potential for fabless design groups to capitalise upon design IP without strong geopraphic advantage is noted.

text: Performance and applications of Gallium-Nitride Monolithic Microwave Integrated Circuits (GaN MMICs) The evolution of wide-bandgap semiconductor transistor technology is placed in historical context with other active device technologies. The relative rapidity of GaN transistor development is noted and is attributed to the great parallel activity in the lighting sector and the historical experience and business model from the III-V compound semiconductor sector. The physical performance expectations for wide-bandgap technologies such as Gallium-Nitride Field-E®ect Transistors (GaN FETs) are reviewed. We present some device characteristics.
Challenges met in characterising, and prospects for modeling GaN FETs are described. Reliability is identified as the final remaining hurdle facing would-be foundries. Evolutionary and unsurprising applications as well as novel and revolutionary applications are suggested. Novel applications include wholly monolithic switchmode power supplies, simplified tools for ablation and diathermy in tissue, and very wide dynamic range circuits for audio or low phase noise signal generation. We conclude that now is the time to embark on circuit design of
MMICs in wide-bandgap technology. The potential for fabless design groups to capitalise upon design IP without strong geopraphic advantage is noted.

year: 2007-12

title: Te Mauri o te Kaitiaki - Exploring Te Ao Māori in environmental relations and kaitiakitanga  in Aotearoa New Zealand

authors: Wareka, Mona-Lisa

subjects: Te Ao Māori

abstract: Indigenous environmental empowerment is on the rise as humans look at ways to slow the adverse effects of anthropogenic environmental degradation. In the context of Aotearoa New Zealand, the concept and practice of ‘kaitiaki’ and ‘kaitiakitanga’, respectfully, play a significant role in the co-existence of Māori with the natural world. Previous research shows the innate connections and responsibilities encompassed in being kaitiaki which extend beyond the human element to encompass nonhumans and spiritual manifestations. This research aims to illustrate how Māori use cultural values, concepts and practices in local-level conservational practices through ethnographic research in Matapōuri. I investigate the conflicts and convergences of a rāhui recently placed on two cultural significant areas to the local hapū, and through this, I analyse the practical and spiritual application of kaitiakitanga. Based on this ethnography, I discuss a model for relating environmental degradation with the wellbeing of Māori within Aotearoa New Zealand today. Here, I wish to highlight the ecological and cultural threats present from continuing in the current system. Lastly, I argue that the assertion of kaitiakitanga at the local-level is also an assertion of Indigenous autonomy for Māori and the environment.

text: Te Mauri o te Kaitiaki - Exploring Te Ao Māori in environmental relations and kaitiakitanga  in Aotearoa New Zealand Indigenous environmental empowerment is on the rise as humans look at ways to slow the adverse effects of anthropogenic environmental degradation. In the context of Aotearoa New Zealand, the concept and practice of ‘kaitiaki’ and ‘kaitiakitanga’, respectfully, play a significant role in the co-existence of Māori with the natural world. Previous research shows the innate connections and responsibilities encompassed in being kaitiaki which extend beyond the human element to encompass nonhumans and spiritual manifestations. This research aims to illustrate how Māori use cultural values, concepts and practices in local-level conservational practices through ethnographic research in Matapōuri. I investigate the conflicts and convergences of a rāhui recently placed on two cultural significant areas to the local hapū, and through this, I analyse the practical and spiritual application of kaitiakitanga. Based on this ethnography, I discuss a model for relating environmental degradation with the wellbeing of Māori within Aotearoa New Zealand today. Here, I wish to highlight the ecological and cultural threats present from continuing in the current system. Lastly, I argue that the assertion of kaitiakitanga at the local-level is also an assertion of Indigenous autonomy for Māori and the environment.

year: 2020