title: Development of low cost PM Ti alloys by thermomechanical processing of powder blends

authors: Raynova, Stiliana (Stella) Rousseva

abstract: This research focuses on the development of low cost powder metallurgy (PM) Ti alloys suitable for application in PM thermomechanical processing with mechanical properties comparable to those of wrought Ti6Al4V alloy. The alloy systems studied are Ti3Al2V, Ti5Fe and Ti3.2Fe1Cr0.6Ni0.1Mo (Ti5SS). The alloy mixtures were produced by blending Ti HDH powders with Al40V, 316SS master alloy powders or elemental Fe powder. The blended powders were further consolidated using various methods: high vacuum sintering (HVS), induction sintering (IS), powder compact forging (PCF) and powder compact extrusion (PCE). It is found that, PM Ti3Al2V and Ti5Fe alloy processed by PCE or PCF followed by recrystallization annealing (RA) achieved tensile properties comparable with wrought Ti6Al4V alloy. Tensile properties such as yield strength (YS) of 910MPa, UTS of 1010MPa and 15% elongation to fracture for Ti3Al2V alloy are reported. Ti5Fe alloy gives YS and UTS of 870MPa and 968MPa respectively, combined with 20.3% elongation to fracture. The tensile results are related to the microstructure developed during the consolidation processes. The oxygen contamination as a result of the high temperature processing is also reported.

text: Development of low cost PM Ti alloys by thermomechanical processing of powder blends This research focuses on the development of low cost powder metallurgy (PM) Ti alloys suitable for application in PM thermomechanical processing with mechanical properties comparable to those of wrought Ti6Al4V alloy. The alloy systems studied are Ti3Al2V, Ti5Fe and Ti3.2Fe1Cr0.6Ni0.1Mo (Ti5SS). The alloy mixtures were produced by blending Ti HDH powders with Al40V, 316SS master alloy powders or elemental Fe powder. The blended powders were further consolidated using various methods: high vacuum sintering (HVS), induction sintering (IS), powder compact forging (PCF) and powder compact extrusion (PCE). It is found that, PM Ti3Al2V and Ti5Fe alloy processed by PCE or PCF followed by recrystallization annealing (RA) achieved tensile properties comparable with wrought Ti6Al4V alloy. Tensile properties such as yield strength (YS) of 910MPa, UTS of 1010MPa and 15% elongation to fracture for Ti3Al2V alloy are reported. Ti5Fe alloy gives YS and UTS of 870MPa and 968MPa respectively, combined with 20.3% elongation to fracture. The tensile results are related to the microstructure developed during the consolidation processes. The oxygen contamination as a result of the high temperature processing is also reported.

year: 2016

title: The autecology of lonicera japonica in a restoration context

authors: Pudney, Kemble Jonathan

subjects: Lonicera japonica

abstract: This thesis concerns the autecology of Lonicera japonica in relation to ecological restoration in Hamilton. It addresses three groups of questions, relating to L. japonica's place in the plant community, its reproduction and spread, and its impacts on other plants. L. japonica's role in the plant communities of natural areas and restoration sites and its variation with environmental factors were studied quantitatively through vegetation measurement and soil analyses at plots established at a naturally regenerating site in Hamilton. Its role under varying disturbance regimes and physical conditions was studied qualitatively and semi-quantitatively at eight other locations. A simple model relating stem diameter to age was developed to assess the age and demography of L. japonica populations. L. japonica's potential to spread was assessed through trials to establish seed and fragment viability, examination of climatic records, and the identification from the literature of potential vectors. Impacts of L. japonica on other species were assessed first through a consideration of the frequency at which plants of differing characteristics are invaded, and second by characterising its impacts upon those plants. The thesis concludes with recommendations for further research and for the management of the plant in restoration areas.
Through the field work it was found that L. japonica is more widely dispersed both within and across natural areas and restoration sites in Hamilton than had been detected from initial site visits, to the extent that it was difficult to detect patterns and relationships at the chosen scale of investigation. It exhibits a tolerance for low pH and wet conditions greater than found in studies overseas, and neither those factors nor soil fertility are likely to limit its spread in restoration and natural areas in New Zealand. However at light levels found
ii
beneath typical native canopy cover the plant's vigour is greatly reduced, and this offers the most promising avenues for control. L. japonica disperses readily via stem fragments incorporating nodes and sets plentiful fertile seed. Though the viability of that seed is short, propagation by this means is possible in Hamilton and may become significant in relation to future restoration work. In good light conditions L. japonica forms dense mats that smother vegetation of low stature and prevent natural succession in canopy gaps, as well as compromising the health of restored areas. In locations with mature canopy L. japonica may survive over lengthy periods on the ground, with restricted vigour, or in canopy-entering clumps that have grown with the host; either form will expand rapidly if light conditions improve. However because of their growth form and trunk texture even mature tree ferns may be killed by L. japonica. Novel elements that have emerged from this study are the plant's tolerance of a wider range of environmental conditions in New Zealand than reported overseas, its potential to spread by seed in local conditions, and an emerging synergistic relationship with another invasive liane, Ipomoea indica. The latter two issues are worthy of further study.

text: The autecology of lonicera japonica in a restoration context This thesis concerns the autecology of Lonicera japonica in relation to ecological restoration in Hamilton. It addresses three groups of questions, relating to L. japonica's place in the plant community, its reproduction and spread, and its impacts on other plants. L. japonica's role in the plant communities of natural areas and restoration sites and its variation with environmental factors were studied quantitatively through vegetation measurement and soil analyses at plots established at a naturally regenerating site in Hamilton. Its role under varying disturbance regimes and physical conditions was studied qualitatively and semi-quantitatively at eight other locations. A simple model relating stem diameter to age was developed to assess the age and demography of L. japonica populations. L. japonica's potential to spread was assessed through trials to establish seed and fragment viability, examination of climatic records, and the identification from the literature of potential vectors. Impacts of L. japonica on other species were assessed first through a consideration of the frequency at which plants of differing characteristics are invaded, and second by characterising its impacts upon those plants. The thesis concludes with recommendations for further research and for the management of the plant in restoration areas.
Through the field work it was found that L. japonica is more widely dispersed both within and across natural areas and restoration sites in Hamilton than had been detected from initial site visits, to the extent that it was difficult to detect patterns and relationships at the chosen scale of investigation. It exhibits a tolerance for low pH and wet conditions greater than found in studies overseas, and neither those factors nor soil fertility are likely to limit its spread in restoration and natural areas in New Zealand. However at light levels found
ii
beneath typical native canopy cover the plant's vigour is greatly reduced, and this offers the most promising avenues for control. L. japonica disperses readily via stem fragments incorporating nodes and sets plentiful fertile seed. Though the viability of that seed is short, propagation by this means is possible in Hamilton and may become significant in relation to future restoration work. In good light conditions L. japonica forms dense mats that smother vegetation of low stature and prevent natural succession in canopy gaps, as well as compromising the health of restored areas. In locations with mature canopy L. japonica may survive over lengthy periods on the ground, with restricted vigour, or in canopy-entering clumps that have grown with the host; either form will expand rapidly if light conditions improve. However because of their growth form and trunk texture even mature tree ferns may be killed by L. japonica. Novel elements that have emerged from this study are the plant's tolerance of a wider range of environmental conditions in New Zealand than reported overseas, its potential to spread by seed in local conditions, and an emerging synergistic relationship with another invasive liane, Ipomoea indica. The latter two issues are worthy of further study.

year: 2009

title: Te whakatipu torekaihuruhuru hai ika-ā-Whiro

authors: Temara, Pou

subjects: Mana tūpuna

abstract: Kai roto i te mōteatea a Hone Tūwhare e mau ana ngā whakaaro me ngā kareāroto o tōku whakatipuranga o Tūhoe i te turakitanga a Mate i te tipua nei i a Te Rangihau i te tau 1987.  Mōwai ana te whenua, takarerewa ana te tangata. He atua te rite o Te Rangihau ki a Tūhoe. Ka kitea ia i ngā marae o Tūhoe, ka hikina te ngoi o te iwi, ka ora. Kua mate nei, tārū ana te iwi; kua hinga te rākau taumatua o ngā manu, kua hinga i te tao o te mate.

Kāore hoki i roa i muri mai o tōna wehenga atu ka whai muri ko tōna rēanga me tōna momo. Mā wai e ārahi te iwi? Mā wai e whakatika te waka ka tikoki, te iwi ka hē? Mā wai o tō mātau whakatipuranga e whakakīkī ngā whāruarua kua mahue mai nei i te ngaronga atu o tērā whakatipuranga taioreore? Koinei ngā mōhio o Tūhoe, he mana te kupu, he tapu te kōrero! Ahakoa i noho rātau ki te ako i a mātau mō te wā e ngaro ai tō rātau momo, tāupetia ana mātau e te mokemoke, he manu mahue i te kātua te rite. Ae, i reira anō ngā torekaihuruhuru e whakatore ana, engari kīhai i a rātau te mana tohunga o te rēanga ka ngaro.

text: Te whakatipu torekaihuruhuru hai ika-ā-Whiro Kai roto i te mōteatea a Hone Tūwhare e mau ana ngā whakaaro me ngā kareāroto o tōku whakatipuranga o Tūhoe i te turakitanga a Mate i te tipua nei i a Te Rangihau i te tau 1987.  Mōwai ana te whenua, takarerewa ana te tangata. He atua te rite o Te Rangihau ki a Tūhoe. Ka kitea ia i ngā marae o Tūhoe, ka hikina te ngoi o te iwi, ka ora. Kua mate nei, tārū ana te iwi; kua hinga te rākau taumatua o ngā manu, kua hinga i te tao o te mate.

Kāore hoki i roa i muri mai o tōna wehenga atu ka whai muri ko tōna rēanga me tōna momo. Mā wai e ārahi te iwi? Mā wai e whakatika te waka ka tikoki, te iwi ka hē? Mā wai o tō mātau whakatipuranga e whakakīkī ngā whāruarua kua mahue mai nei i te ngaronga atu o tērā whakatipuranga taioreore? Koinei ngā mōhio o Tūhoe, he mana te kupu, he tapu te kōrero! Ahakoa i noho rātau ki te ako i a mātau mō te wā e ngaro ai tō rātau momo, tāupetia ana mātau e te mokemoke, he manu mahue i te kātua te rite. Ae, i reira anō ngā torekaihuruhuru e whakatore ana, engari kīhai i a rātau te mana tohunga o te rēanga ka ngaro.

year: 2016