title: Towards an understanding of thermodynamic and kinetic controls on the formation of clay minerals from volcanic glass under various environmental conditions

authors: Hodder, A.P.W.

abstract: lmogolite is the kinetically and thermodynamically favoured weathering product from rhyolitic volcanic glass in the soil-forming environment. However, on thermodynamic grounds imogolite would also appear to be the favoured alteration product of rhyolitic glass deposited in the nearshore marine environment. On the basis that the rate of conversion of glass to clay minerals is a function of the solubility of the clay mineral, smectite is expected to be formed under mildly diagenetic conditions, and formed more rapidly than imogolite in soil. The derived activation energies for formation of imogolite from glass in soils are appropriate for a diffusion controlled reaction, and appear consistent with the diffusion of the tetrahedrally co-ordinated species Al[iv](OH)₂(H2Q)⁺. In the marine environment, however the mechanism for all reactions appear to be surface reaction control.

text: Towards an understanding of thermodynamic and kinetic controls on the formation of clay minerals from volcanic glass under various environmental conditions lmogolite is the kinetically and thermodynamically favoured weathering product from rhyolitic volcanic glass in the soil-forming environment. However, on thermodynamic grounds imogolite would also appear to be the favoured alteration product of rhyolitic glass deposited in the nearshore marine environment. On the basis that the rate of conversion of glass to clay minerals is a function of the solubility of the clay mineral, smectite is expected to be formed under mildly diagenetic conditions, and formed more rapidly than imogolite in soil. The derived activation energies for formation of imogolite from glass in soils are appropriate for a diffusion controlled reaction, and appear consistent with the diffusion of the tetrahedrally co-ordinated species Al[iv](OH)₂(H2Q)⁺. In the marine environment, however the mechanism for all reactions appear to be surface reaction control.

year: 1996-01-01

title: A numerical model to simulate the formation and subsequent evolution of tidal channel networks

authors: van Maanen, Barend

subjects: Long-term morphological evolution

abstract: We present a numerical model that simulates morphological change as a result of the interactions between hydrodynamics, sediment transport and bed elevation change. Numerical simulations indicate that these morphodynamic interactions can lead to the initiation of tidal channels and potentially give rise to large-scale channel networks. We perform a sensitivity analysis to show how model outcome is sensitive to the numerical scheme adopted, hydrodynamic and morphological time-steps, and initial bathymetry. Furthermore, the formation of tidal channels and intertidal areas affects both the large-scale flow patterns, as well as the asymmetry between flood- and ebb-tidal currents.

text: A numerical model to simulate the formation and subsequent evolution of tidal channel networks We present a numerical model that simulates morphological change as a result of the interactions between hydrodynamics, sediment transport and bed elevation change. Numerical simulations indicate that these morphodynamic interactions can lead to the initiation of tidal channels and potentially give rise to large-scale channel networks. We perform a sensitivity analysis to show how model outcome is sensitive to the numerical scheme adopted, hydrodynamic and morphological time-steps, and initial bathymetry. Furthermore, the formation of tidal channels and intertidal areas affects both the large-scale flow patterns, as well as the asymmetry between flood- and ebb-tidal currents.

year: 2011

title: Participatory design in Māori cultural contexts

authors: Bowen, Judy

subjects: computer science

abstract: The Hakituri project aims to develop practical and ethical wearable monitoring solutions for workers in hazardous industries. We identified specific challenges pertinent to our participatory design process for this project which relate to the indigenous participants, cultural expectations and data sovereignty. As we developed the ideas for our design process, further challenges became evident. In this paper we explore the challenges that unfolded and describe how we began to mitigate them and develop ideas for similar future challenges.

text: Participatory design in Māori cultural contexts The Hakituri project aims to develop practical and ethical wearable monitoring solutions for workers in hazardous industries. We identified specific challenges pertinent to our participatory design process for this project which relate to the indigenous participants, cultural expectations and data sovereignty. As we developed the ideas for our design process, further challenges became evident. In this paper we explore the challenges that unfolded and describe how we began to mitigate them and develop ideas for similar future challenges.

year: 2020