title: Optimization of Sol–Gel-Formed ZnO:Al Processing Parameters by Observation of Dopant Ion Location Using Solid-State ²⁷Al NMR Spectrometry

authors: Kemmitt, Tim

subjects: chemistry

abstract: We report the discrimination of Al doping sites in sol–gel-formed ZnO powders by solid-state 27Al nuclear magnetic resonance (NMR) spectrometry. A degree of control of dopant placement is demonstrated by modifying sol precursors and processing parameters. ZnO powders containing 1–8 at. % aluminum ions were prepared from aqueous citrate-amino-alcohol-based gels calcined at 500 °C. The powders were characterized using ²⁷Al NMR spectrometry, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Solid-state ²⁷Al NMR spectrometry clearly distinguished between different Al environments and was effective in determining the relative amounts of incorporation of Al dopant ions into the Zn lattice sites in the zincite structure. This allowed a synthesis protocol to be developed to optimize the doping effectiveness. Relatively minor variations in processing conditions could influence the degree and mode of Al incorporation. Optimal conditions were found to include a 90 °C drying step, followed by placement in a preheated (500 °C) furnace for 1 h. An ethanolamine-containing precursor was shown to perform much better than precursors containing alternative amino alcohols.

text: Optimization of Sol–Gel-Formed ZnO:Al Processing Parameters by Observation of Dopant Ion Location Using Solid-State ²⁷Al NMR Spectrometry We report the discrimination of Al doping sites in sol–gel-formed ZnO powders by solid-state 27Al nuclear magnetic resonance (NMR) spectrometry. A degree of control of dopant placement is demonstrated by modifying sol precursors and processing parameters. ZnO powders containing 1–8 at. % aluminum ions were prepared from aqueous citrate-amino-alcohol-based gels calcined at 500 °C. The powders were characterized using ²⁷Al NMR spectrometry, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Solid-state ²⁷Al NMR spectrometry clearly distinguished between different Al environments and was effective in determining the relative amounts of incorporation of Al dopant ions into the Zn lattice sites in the zincite structure. This allowed a synthesis protocol to be developed to optimize the doping effectiveness. Relatively minor variations in processing conditions could influence the degree and mode of Al incorporation. Optimal conditions were found to include a 90 °C drying step, followed by placement in a preheated (500 °C) furnace for 1 h. An ethanolamine-containing precursor was shown to perform much better than precursors containing alternative amino alcohols.

year: 2011

title: Refugee status and religious conversion: The significance of refugee appeal number 76204

authors: Tennent, Douglas

abstract: Doug Tennent from Waikato University considers the effect of adverse findings of credibility in a refugee claim involving religious conversion and cautions the need for support agencies to act with care when assisting people with refugee determinations

text: Refugee status and religious conversion: The significance of refugee appeal number 76204 Doug Tennent from Waikato University considers the effect of adverse findings of credibility in a refugee claim involving religious conversion and cautions the need for support agencies to act with care when assisting people with refugee determinations

year: 2010

title: Ngā mahi: Kaupapa Māori outcomes and indicators kete

authors: Jefferies, Richard

subjects: New Zealand

abstract: As part of the Planning Under Cooperative Mandates research (PUCM) we developed a kaupapa Māori outcomes and indicators framework. This framework reflects tikanga Māori and Māori values. It also considers issues (including environmental issues) according to those tikanga that particular issues invoke. For example, tikanga brought into play in relation to council treatment and disposal of sewerage include tapu (sacred), and might also impact on the mauri (life-force) of water if treated effluent were to enter waterways.

The intention of our research has been to clarify and define key Māori environmental concepts so that stakeholders (including council staff) will have a terms of reference against which they can compare desired environmental outcomes from different perspectives and be better placed to integrate Māori environmental outcomes into planning processes. The end-point is this Nga Mahi kete report containing tikanga-based worksheets and the guidelines for using them.

text: Ngā mahi: Kaupapa Māori outcomes and indicators kete As part of the Planning Under Cooperative Mandates research (PUCM) we developed a kaupapa Māori outcomes and indicators framework. This framework reflects tikanga Māori and Māori values. It also considers issues (including environmental issues) according to those tikanga that particular issues invoke. For example, tikanga brought into play in relation to council treatment and disposal of sewerage include tapu (sacred), and might also impact on the mauri (life-force) of water if treated effluent were to enter waterways.

The intention of our research has been to clarify and define key Māori environmental concepts so that stakeholders (including council staff) will have a terms of reference against which they can compare desired environmental outcomes from different perspectives and be better placed to integrate Māori environmental outcomes into planning processes. The end-point is this Nga Mahi kete report containing tikanga-based worksheets and the guidelines for using them.

year: 2009-06-30