title: Components of regional population growth, 1986-2001

authors: Pool, Ian

subjects: population growth

abstract: The vitality of a region is frequently assessed by looking at its population growth pattern. This is seen as being linked to its economic and social vibrancy. To better understand the dynamics of this growth pattern it is necessary to decompose population growth into the contributions of natural increase (births less deaths) and migration (both domestic and international). This provides a demographic accounting of the factors of population change which we use to analyse the degree to which the levels and impacts of these factors differ between the Regional Council Areas of New Zealand. We find large variations between Regional Council Areas in overall population growth for the three quinquennia between 1986 and 2001. The Auckland region experienced the largest growth, coming both from high natural increase and international migration, while the “sunbelt” regions of Bay of Plenty, Nelson-Tasman and Marlborough had high growth, but driven by internal migration. In other regions, such as Gisborne, West Coast and Southland population growth declined.

text: Components of regional population growth, 1986-2001 The vitality of a region is frequently assessed by looking at its population growth pattern. This is seen as being linked to its economic and social vibrancy. To better understand the dynamics of this growth pattern it is necessary to decompose population growth into the contributions of natural increase (births less deaths) and migration (both domestic and international). This provides a demographic accounting of the factors of population change which we use to analyse the degree to which the levels and impacts of these factors differ between the Regional Council Areas of New Zealand. We find large variations between Regional Council Areas in overall population growth for the three quinquennia between 1986 and 2001. The Auckland region experienced the largest growth, coming both from high natural increase and international migration, while the “sunbelt” regions of Bay of Plenty, Nelson-Tasman and Marlborough had high growth, but driven by internal migration. In other regions, such as Gisborne, West Coast and Southland population growth declined.

year: 2004-05

title: Permeance based modelling, design and optimization of supercapacitor assisted surge absorber (SCASA)

authors: Silva Thotabaddadurage, Sadeeshvara Udayanga

subjects: Surge protection

abstract: Supercapacitor assisted (SCA) techniques are a unique set of circuit topologies designed to fulfil power conversion and protection tasks by circumventing the energy losses normally associated with RC based circuits. With million times larger capacitance compared to electrolytic type, supercapacitors (SCs) have shown a remarkable surge endurance as discovered by the University of Waikato (UoW) power electronics group. This thesis examines a patented SCA surge protector based on the novel use of SCs' surge withstanding capability, and investigates ways to optimize the present design based on the improvements made to circuit's magnetic components.

The supercapacitor assisted surge absorber (SCASA) developed at UoW incorporates a coupled-inductor wound to a specially selected magnetic material—powdered-iron—that absorbs transients. Despite its high performance, the circuit generates a secondary effect of a negative voltage-peak due to inductive energy release by the core. One aim of our study is to eliminate this undesirable voltage spike using air-gapped ferrite cores. We first identified coupled-inductor transformer action under contrasting voltage conditions. In predicting the SCASA operation under both 50 Hz AC and transient conditions, a permeance based model is used. Our model highlights non-ideal characteristics of the coupled-inductor such as leakage and magnetizing inductances, and provides theoretical predictions based on the permeance coefficients extracted from manufacturer specifications. Inductance measurements are taken over a range of kilohertz frequencies to confirm the accuracy of modelling work.

During initial investigations, we inserted air gaps to ferrite toroids to enhance surge energy storage capability and fringing losses associated with the core. Single- and double-gapped core approach we tested yielded positive test results showing a reduction in negative-surge effect. This encouraged us to develop circuit prototypes using commercially available (Magnetics Inc.) gapped cores of EER type which has an effective permeance comparable to original powdered-iron toroid. This new core configuration indicated improved performance under transient conditions while continually facilitating the passage of AC mains power. In particular, air-gapped cores resulted in optimizing SCASA performance by showing:
•	95% depletion of the negative-surge effect associated with the coupled-inductor
•	~10% reduction of MOV clamping improving the load-side voltage characteristics
•	improved surge endurance as per UL-1449 test standards
•	minimized inductance tolerance and reduced manufacturing cost
To comprehend SCASA surge propagation, we applied a Laplace transform analysis to predict primary and secondary transient currents in the coupled-inductor. Compared to ideal transformer action, we quantify how the primary:secondary current ratio deviates from the turns ratio due to magnetic reluctance of powdered-iron. LTSpice numerical simulations further confirm our analytical predictions.

All experimental procedures presented in this thesis are compliant with IEEE C62.41/IEC 61000-4-5 standards, and generated using a lightning surge simulator (Noiseken LSS-6230) coupled to 230 V, 50 Hz utility mains. Test results generated under these conditions were all within 10% of the predictions showing good consistency with the theorized models.

text: Permeance based modelling, design and optimization of supercapacitor assisted surge absorber (SCASA) Supercapacitor assisted (SCA) techniques are a unique set of circuit topologies designed to fulfil power conversion and protection tasks by circumventing the energy losses normally associated with RC based circuits. With million times larger capacitance compared to electrolytic type, supercapacitors (SCs) have shown a remarkable surge endurance as discovered by the University of Waikato (UoW) power electronics group. This thesis examines a patented SCA surge protector based on the novel use of SCs' surge withstanding capability, and investigates ways to optimize the present design based on the improvements made to circuit's magnetic components.

The supercapacitor assisted surge absorber (SCASA) developed at UoW incorporates a coupled-inductor wound to a specially selected magnetic material—powdered-iron—that absorbs transients. Despite its high performance, the circuit generates a secondary effect of a negative voltage-peak due to inductive energy release by the core. One aim of our study is to eliminate this undesirable voltage spike using air-gapped ferrite cores. We first identified coupled-inductor transformer action under contrasting voltage conditions. In predicting the SCASA operation under both 50 Hz AC and transient conditions, a permeance based model is used. Our model highlights non-ideal characteristics of the coupled-inductor such as leakage and magnetizing inductances, and provides theoretical predictions based on the permeance coefficients extracted from manufacturer specifications. Inductance measurements are taken over a range of kilohertz frequencies to confirm the accuracy of modelling work.

During initial investigations, we inserted air gaps to ferrite toroids to enhance surge energy storage capability and fringing losses associated with the core. Single- and double-gapped core approach we tested yielded positive test results showing a reduction in negative-surge effect. This encouraged us to develop circuit prototypes using commercially available (Magnetics Inc.) gapped cores of EER type which has an effective permeance comparable to original powdered-iron toroid. This new core configuration indicated improved performance under transient conditions while continually facilitating the passage of AC mains power. In particular, air-gapped cores resulted in optimizing SCASA performance by showing:
•	95% depletion of the negative-surge effect associated with the coupled-inductor
•	~10% reduction of MOV clamping improving the load-side voltage characteristics
•	improved surge endurance as per UL-1449 test standards
•	minimized inductance tolerance and reduced manufacturing cost
To comprehend SCASA surge propagation, we applied a Laplace transform analysis to predict primary and secondary transient currents in the coupled-inductor. Compared to ideal transformer action, we quantify how the primary:secondary current ratio deviates from the turns ratio due to magnetic reluctance of powdered-iron. LTSpice numerical simulations further confirm our analytical predictions.

All experimental procedures presented in this thesis are compliant with IEEE C62.41/IEC 61000-4-5 standards, and generated using a lightning surge simulator (Noiseken LSS-6230) coupled to 230 V, 50 Hz utility mains. Test results generated under these conditions were all within 10% of the predictions showing good consistency with the theorized models.

year: 2021

title: Young people, technology and the future of te Reo Māori

authors: Keegan, Te Taka Adrian Gregory

abstract: After decades of neglect and, in some instances, suppression, te reo Māori has achieved a degree of recognition and support from the Government and people. Language strategies have been written, schooling is available in both languages, and since 1987 the language has had official status. However, despite demonstrable progress in some areas, it remains a small-minority language. Within New Zealand there are 157,000 speakers of te reo Māori, about 4.1 percent of the population (Statistics New Zealand: Te Tari Tatau, 2007), and the language is classified as 'vulnerable' by UNESCO (Mosley, 2010). The language continues to face considerable pressure from English, not just because English is a majority national language but because it is an increasingly global language, with a significant presence in culture, science, media and technology. This chapter considers the relationships between young people, technology and te reo Māori. It argues that technology is an important domain of use for te reo Māori, particularly the continued use of the language by young people.

text: Young people, technology and the future of te Reo Māori After decades of neglect and, in some instances, suppression, te reo Māori has achieved a degree of recognition and support from the Government and people. Language strategies have been written, schooling is available in both languages, and since 1987 the language has had official status. However, despite demonstrable progress in some areas, it remains a small-minority language. Within New Zealand there are 157,000 speakers of te reo Māori, about 4.1 percent of the population (Statistics New Zealand: Te Tari Tatau, 2007), and the language is classified as 'vulnerable' by UNESCO (Mosley, 2010). The language continues to face considerable pressure from English, not just because English is a majority national language but because it is an increasingly global language, with a significant presence in culture, science, media and technology. This chapter considers the relationships between young people, technology and te reo Māori. It argues that technology is an important domain of use for te reo Māori, particularly the continued use of the language by young people.

year: 2014