title: Threshold concept knowledge in analogue electronics: Support and assessment

authors: Harlow, Ann

abstract: In electrical engineering, as in other academic disciplines, there exist special, threshold concepts, where students often get stuck but which once grasped reveal new ways of thinking about a subject. Two surveys, student interviews and focus group discussions, and students’ assessment were directed at learning of threshold concepts and their pre-cursors. Results suggest that one of the precursor concepts, current flow, may be a threshold concept in itself. A model of precursor and threshold concepts assessment and additional student-support for learning threshold concepts is suggested.

text: Threshold concept knowledge in analogue electronics: Support and assessment In electrical engineering, as in other academic disciplines, there exist special, threshold concepts, where students often get stuck but which once grasped reveal new ways of thinking about a subject. Two surveys, student interviews and focus group discussions, and students’ assessment were directed at learning of threshold concepts and their pre-cursors. Results suggest that one of the precursor concepts, current flow, may be a threshold concept in itself. A model of precursor and threshold concepts assessment and additional student-support for learning threshold concepts is suggested.

year: 2012

title: Oceanographic and morphodynamic monitoring of a multi-purpose reef at Mount Maunganui, New Zealand

authors: Weppe, Simon Bastien

subjects: multi-purpose reef

abstract: The innovative concept of an offshore submerged multi-purpose reef combining a
coastal protection function with recreational benefits including improved surfing,
diving, or fishing conditions provides an appealing solution for the management
of beaches. However, since the technology is relatively recent, there is still a lack
of empirical knowledge about its performance in the field. The present research
monitored the effect of the prototype  research  reef constructed at Mount
Maunganui in New Zealand on the local beach morphodynamics and
oceanographic conditions, being primarily concerned with implications on the
coastal protection function of the technology.
The beach morphodynamic response to the reef was investigated from a set of
already available high resolution bathymetric surveys imaging the foreshore and
surfzone morphology prior to, and throughout reef construction, and a new postconstruction
survey collected as a part of this research. The reef implementation
was found to disturb the pre-existing beach state functioning including the
onshore/offshore migration of the underlying long shore bar, rather than cause a
persistent salient response. A possible additional beach width of ~ 20 m,
extending ~ 150 m alongshore was identified in the lee of the reef from shoreline
analysis, but the pattern was transient throughout the monitoring period since it
was superimposed on comparatively large pre-existing fluctuations. In addition,
the reef structure provided a control point on the offshore morphology able to trap
sediment updrift and erode sediment downdrift.
Both field measurements and numerical modelling of waves and currents were
used to monitor the effect of the reef on the oceanographic conditions. Wave
propagation over the reef without breaking (H less than 0.5 m) resulted in transmitted
heights larger than incident by up to a factor of 2. When the reef triggered
breaking, transmitted heights were reduced by up to ~40 %. A concurrent process
was the shift of the wave energy spectra towards higher frequencies landward of
the reef that resulted in reduced transmitted wave periods. Wave modelling
showed that the wave shadowing was associated with significant wave rotation
around the reef that induced two zones of divergent wave angles near the
shoreline in the lee of the reef. The hydrodynamic response to the wave energy
dissipation was the development of stronger onshore directed currents landward of
the reef. Hydrodynamic modelling indicated that the reef-induced flow forced a
cellular circulation in the lee side under shore normal waves, and an onshore
deviation of the ambient (unidirectional) long-shore currents under oblique waves.
The research provided a rare empirical test to the theoretical design concepts, and
potential supplements or refinements. To obtain the required beach protection, the
reef impact on the beach morphodynamic coupling including wave
transformation, nearshore hydrodynamics, and small/large scale beach state
response needs to be carefully assessed.

text: Oceanographic and morphodynamic monitoring of a multi-purpose reef at Mount Maunganui, New Zealand The innovative concept of an offshore submerged multi-purpose reef combining a
coastal protection function with recreational benefits including improved surfing,
diving, or fishing conditions provides an appealing solution for the management
of beaches. However, since the technology is relatively recent, there is still a lack
of empirical knowledge about its performance in the field. The present research
monitored the effect of the prototype  research  reef constructed at Mount
Maunganui in New Zealand on the local beach morphodynamics and
oceanographic conditions, being primarily concerned with implications on the
coastal protection function of the technology.
The beach morphodynamic response to the reef was investigated from a set of
already available high resolution bathymetric surveys imaging the foreshore and
surfzone morphology prior to, and throughout reef construction, and a new postconstruction
survey collected as a part of this research. The reef implementation
was found to disturb the pre-existing beach state functioning including the
onshore/offshore migration of the underlying long shore bar, rather than cause a
persistent salient response. A possible additional beach width of ~ 20 m,
extending ~ 150 m alongshore was identified in the lee of the reef from shoreline
analysis, but the pattern was transient throughout the monitoring period since it
was superimposed on comparatively large pre-existing fluctuations. In addition,
the reef structure provided a control point on the offshore morphology able to trap
sediment updrift and erode sediment downdrift.
Both field measurements and numerical modelling of waves and currents were
used to monitor the effect of the reef on the oceanographic conditions. Wave
propagation over the reef without breaking (H less than 0.5 m) resulted in transmitted
heights larger than incident by up to a factor of 2. When the reef triggered
breaking, transmitted heights were reduced by up to ~40 %. A concurrent process
was the shift of the wave energy spectra towards higher frequencies landward of
the reef that resulted in reduced transmitted wave periods. Wave modelling
showed that the wave shadowing was associated with significant wave rotation
around the reef that induced two zones of divergent wave angles near the
shoreline in the lee of the reef. The hydrodynamic response to the wave energy
dissipation was the development of stronger onshore directed currents landward of
the reef. Hydrodynamic modelling indicated that the reef-induced flow forced a
cellular circulation in the lee side under shore normal waves, and an onshore
deviation of the ambient (unidirectional) long-shore currents under oblique waves.
The research provided a rare empirical test to the theoretical design concepts, and
potential supplements or refinements. To obtain the required beach protection, the
reef impact on the beach morphodynamic coupling including wave
transformation, nearshore hydrodynamics, and small/large scale beach state
response needs to be carefully assessed.

year: 2010

title: Paradoxical mobilities: sharemilking with Te Raparahi Lands Trust (Wāotū)

authors: Hutcheson, Gail Yvonne

subjects: mobilities

abstract: Mobilities are important for capturing some of the combined movements of people, animals and objects in all of their complex relational dynamics. Sharemilking involves a cascade of mobilities: from the modest journies of the everyday to the upheaval of complete farm moves. Here we examine how sharemilkers are enabled and constrained in different ways by being mobile and landless, but also included are hopeful geographies. The sharemilker's mobile relationship to land, rather than ownership of it, works well with indigenous ideas of kaitiakitanga (guardianship) that is a central feature of multiply owned Māori land trust (Te Raparahi). Combining sharemilker mobility with te Raparahi, and importantly Ngāti Hūri historical and contemporary connections to Te Wāotū in South Waikato, Aotearoa New Zealand, reveals paradoxical mobilities of place.

text: Paradoxical mobilities: sharemilking with Te Raparahi Lands Trust (Wāotū) Mobilities are important for capturing some of the combined movements of people, animals and objects in all of their complex relational dynamics. Sharemilking involves a cascade of mobilities: from the modest journies of the everyday to the upheaval of complete farm moves. Here we examine how sharemilkers are enabled and constrained in different ways by being mobile and landless, but also included are hopeful geographies. The sharemilker's mobile relationship to land, rather than ownership of it, works well with indigenous ideas of kaitiakitanga (guardianship) that is a central feature of multiply owned Māori land trust (Te Raparahi). Combining sharemilker mobility with te Raparahi, and importantly Ngāti Hūri historical and contemporary connections to Te Wāotū in South Waikato, Aotearoa New Zealand, reveals paradoxical mobilities of place.

year: 2017