title: Kelvin-Helmholtz instability in aluminium reduction cells

authors: Shin, Sung Nam

abstract: In aluminium reduction cells the intense magnetic fields and associated Lorentz forces drive steady flows in the cryolite and aluminium layers. Generally there is a discontinuity in velocity between the layers, which gives rise to a Kelvin-Helmholtz instability, and the study of this effect is the subject of the thesis. 

The role of the basic steady flow is focused in this analysis, while most previous MHD analyses neglect it and emphasise on the interaction between the interface wave and the electromagnetic field by the electromagnetic perturbation. The stationary magnetic field is considered important as a strong driving source for the steady velocity in our model. 

Steady velocity fields are studied in terms of a stream function and global stability criteria are discussed with disturbances. Non-linear evolution of flow is investigated to find a steady condition and show that steady flows are stable. A normal mode analysis is used to formulate wave evolution equations, which are integrated forwards in time. 

Also an improved treatment of electromagnetic damping is developed, which includes the effect of the induced electric field. 

Using a normal mode form of the steady-state current, magnetic field or flow, the scheme developed in this research is suitable for industrial application where these would be calculated numerically.

text: Kelvin-Helmholtz instability in aluminium reduction cells In aluminium reduction cells the intense magnetic fields and associated Lorentz forces drive steady flows in the cryolite and aluminium layers. Generally there is a discontinuity in velocity between the layers, which gives rise to a Kelvin-Helmholtz instability, and the study of this effect is the subject of the thesis. 

The role of the basic steady flow is focused in this analysis, while most previous MHD analyses neglect it and emphasise on the interaction between the interface wave and the electromagnetic field by the electromagnetic perturbation. The stationary magnetic field is considered important as a strong driving source for the steady velocity in our model. 

Steady velocity fields are studied in terms of a stream function and global stability criteria are discussed with disturbances. Non-linear evolution of flow is investigated to find a steady condition and show that steady flows are stable. A normal mode analysis is used to formulate wave evolution equations, which are integrated forwards in time. 

Also an improved treatment of electromagnetic damping is developed, which includes the effect of the induced electric field. 

Using a normal mode form of the steady-state current, magnetic field or flow, the scheme developed in this research is suitable for industrial application where these would be calculated numerically.

year: 2000

title: Past, present and future urban water: The challenges in creating more beneficial trajectories

authors: White, Iain

abstract: Alternative visions of cities that treat water more sustainably are becoming more compelling as understanding increases of current impacts and future pressures. Here, an alternative relationship between water, space and citizens is commonly advocated that represents a significant shift from the techno-rational supply-oriented emphasis of the twentieth century. In discussions connected to any transition to a more beneficial urban water trajectory, aspects such as land use change, new technologies or innovative policies are frequently held up as being critical elements. Rather than focus on any notional Water Sensitive City as an outcome to be achieved, this chapter complements this literature by critically examining the processes that may help or hinder transitions of this nature. It firstly explores the historical states of urban water management and links to the wider socio-political context within which change must occur. It then analyses issues related to the speed and scale of land use change, emphasising how every urban area has differing flows of finance, regeneration opportunities or free development space. The argument then turns to path dependence and how institutional, cultural and technological norms may resist attempts at change, before focusing on the difficulties in enabling effective policy transfer across what are distinct territories and contexts. It ends with a discussion on how water is just one of an increasing number of competing urban visions – from the Smart City to the Resilient City – all of which are fighting for attention, resources and action.

text: Past, present and future urban water: The challenges in creating more beneficial trajectories Alternative visions of cities that treat water more sustainably are becoming more compelling as understanding increases of current impacts and future pressures. Here, an alternative relationship between water, space and citizens is commonly advocated that represents a significant shift from the techno-rational supply-oriented emphasis of the twentieth century. In discussions connected to any transition to a more beneficial urban water trajectory, aspects such as land use change, new technologies or innovative policies are frequently held up as being critical elements. Rather than focus on any notional Water Sensitive City as an outcome to be achieved, this chapter complements this literature by critically examining the processes that may help or hinder transitions of this nature. It firstly explores the historical states of urban water management and links to the wider socio-political context within which change must occur. It then analyses issues related to the speed and scale of land use change, emphasising how every urban area has differing flows of finance, regeneration opportunities or free development space. The argument then turns to path dependence and how institutional, cultural and technological norms may resist attempts at change, before focusing on the difficulties in enabling effective policy transfer across what are distinct territories and contexts. It ends with a discussion on how water is just one of an increasing number of competing urban visions – from the Smart City to the Resilient City – all of which are fighting for attention, resources and action.

year: 2017

title: Representations of te reo Māori and te ao Māori in a translingual picturebook: How my Koro became a Star

authors: Barbour, Julie Renee

subjects: Indigenous language and culture

abstract: While English is the most commonly used language in Aotearoa New Zealand, it is a multilingual nation with two languages recognised as official: te reo Māori (the Māori language) and New Zealand Sign Language. The English language is dominant in children’s literature published in Aotearoa New Zealand, but since the 1980s there has been an increase in the number of picturebooks featuring two languages, te reo Māori and English. Previous work has explored how representations of te reo Māori and English in pukapuka pikitia reorua (dual language picturebooks) in Aotearoa reflect changing attitudes towards the two languages. In this article, we focus particularly on Brianne Te Paa and Story Hemi-Morehouse’s picturebook How my Koro became a Star. Originally written in te reo Māori, this multi-award winning picturebook is located at the beginning of Matariki, the Māori New Year celebration. In a move away from the linguistic analysis of te reo Māori being ‘borrowed’ by English, we consider how storytellers like Te Paa weave Māori language together with English in a translingual publication, supporting reader comprehension of Māori vocabulary and cultural meanings through embedded illustrations and explanations, inviting the curious reader to learn beyond the story.

text: Representations of te reo Māori and te ao Māori in a translingual picturebook: How my Koro became a Star While English is the most commonly used language in Aotearoa New Zealand, it is a multilingual nation with two languages recognised as official: te reo Māori (the Māori language) and New Zealand Sign Language. The English language is dominant in children’s literature published in Aotearoa New Zealand, but since the 1980s there has been an increase in the number of picturebooks featuring two languages, te reo Māori and English. Previous work has explored how representations of te reo Māori and English in pukapuka pikitia reorua (dual language picturebooks) in Aotearoa reflect changing attitudes towards the two languages. In this article, we focus particularly on Brianne Te Paa and Story Hemi-Morehouse’s picturebook How my Koro became a Star. Originally written in te reo Māori, this multi-award winning picturebook is located at the beginning of Matariki, the Māori New Year celebration. In a move away from the linguistic analysis of te reo Māori being ‘borrowed’ by English, we consider how storytellers like Te Paa weave Māori language together with English in a translingual publication, supporting reader comprehension of Māori vocabulary and cultural meanings through embedded illustrations and explanations, inviting the curious reader to learn beyond the story.

year: 2025