title: Viscous effects in time-dependent planar reconnection

authors: Armstrong, Craig Keith

subjects: magnetic reconnection

abstract: Context. Viscous dissipation is expected to play a significant part in energy release in solar flares, yet the role of viscosity in a weakly resistive plasma of the solar corona remains unclear.

Aims. We attempt to clarify the role of viscous effects in magnetic reconnection by performing simulations of reconnection in planar periodic geometry in an incompressible viscous resistive plasma. 
Methods. We consider magnetic reconnection, driven by large-scale vortical flows. We use both the classical shear viscosity and the Braginskii form for the ion parallel viscosity in a magnetised plasma. We determine the scalings of the current sheet parameters and the global rates of resistive and viscous dissipation. We use steady-state exact solutions and scaling arguments to interpret the numerical results.
Results. We show that, regardless of the form of viscosity, the resistive non-viscous analytical solutions for flux pile-up merging provide a very good approximation of the numerical results in the reconnecting current sheet. We find no evidence for a visco-resistive scale. Numerical results for a highly sheared magnetic field, however, appear to deviate from the analytical predictions in the case of the Braginskii viscosity.

text: Viscous effects in time-dependent planar reconnection Context. Viscous dissipation is expected to play a significant part in energy release in solar flares, yet the role of viscosity in a weakly resistive plasma of the solar corona remains unclear.

Aims. We attempt to clarify the role of viscous effects in magnetic reconnection by performing simulations of reconnection in planar periodic geometry in an incompressible viscous resistive plasma. 
Methods. We consider magnetic reconnection, driven by large-scale vortical flows. We use both the classical shear viscosity and the Braginskii form for the ion parallel viscosity in a magnetised plasma. We determine the scalings of the current sheet parameters and the global rates of resistive and viscous dissipation. We use steady-state exact solutions and scaling arguments to interpret the numerical results.
Results. We show that, regardless of the form of viscosity, the resistive non-viscous analytical solutions for flux pile-up merging provide a very good approximation of the numerical results in the reconnecting current sheet. We find no evidence for a visco-resistive scale. Numerical results for a highly sheared magnetic field, however, appear to deviate from the analytical predictions in the case of the Braginskii viscosity.

year: 2011

title: Tracking and re-finding printed material using a personal digital library

authors: Hinze, Annika

subjects: computer science

abstract: Most web searches aim to re-find previously known information or documents. Keeping track of one’s digital and printed reading material is known to be a challenging and costly task. We describe the design, implementation and evaluation of our Human-centred workplace (HCW) – a system that supports the tracking of physical document printouts. HCW embeds QR codes in the document printout, stores the documents in a personal Digital Library, and uses cameras in the office to track changes in the document locations. We explored the HCW in three evaluations, using the system over several weeks in an office setting, a user study in a lab environment, and extensive functional tests.

text: Tracking and re-finding printed material using a personal digital library Most web searches aim to re-find previously known information or documents. Keeping track of one’s digital and printed reading material is known to be a challenging and costly task. We describe the design, implementation and evaluation of our Human-centred workplace (HCW) – a system that supports the tracking of physical document printouts. HCW embeds QR codes in the document printout, stores the documents in a personal Digital Library, and uses cameras in the office to track changes in the document locations. We explored the HCW in three evaluations, using the system over several weeks in an office setting, a user study in a lab environment, and extensive functional tests.

year: 2016

title: Final arrangements following death: Maori indigenous decision making and tangi

authors: Nikora, Linda Waimarie

subjects: Maori death rituals

abstract: Death is a universal event. It will happen to all of us, yet how we respond to death is particular and influenced by our cultural worlds. This study offers an investigation of the idiographic, of how one woman responded to, and made arrangements to, mourn and bury her mother. Specifically, we explore how she and her whanau (family) under pressure of time and grief and in the absence of clear final wishes, met to consider issues and make decisions about the situation they were confronted with. This case forms part of a much larger programme of research into Maori death rituals, change and adaption. Informing a scholarly audience unfamiliar with the Maori world requires a significant amount of contextual information. The case study is a powerful strategy to achieve this and one that draws readers into deep understanding (Willig, 2008). This case provides insight into the struggles of an indigenous fourth-world people living within the heterogeneity of Aotearoa/New Zealand society; it demonstrates how values change across generations as people live their lives increasingly away from their ancestral homelands; and how traditionally defined roles and responsibilities within the whanau (family) are challenged by members living away from each other.

text: Final arrangements following death: Maori indigenous decision making and tangi Death is a universal event. It will happen to all of us, yet how we respond to death is particular and influenced by our cultural worlds. This study offers an investigation of the idiographic, of how one woman responded to, and made arrangements to, mourn and bury her mother. Specifically, we explore how she and her whanau (family) under pressure of time and grief and in the absence of clear final wishes, met to consider issues and make decisions about the situation they were confronted with. This case forms part of a much larger programme of research into Maori death rituals, change and adaption. Informing a scholarly audience unfamiliar with the Maori world requires a significant amount of contextual information. The case study is a powerful strategy to achieve this and one that draws readers into deep understanding (Willig, 2008). This case provides insight into the struggles of an indigenous fourth-world people living within the heterogeneity of Aotearoa/New Zealand society; it demonstrates how values change across generations as people live their lives increasingly away from their ancestral homelands; and how traditionally defined roles and responsibilities within the whanau (family) are challenged by members living away from each other.

year: 2012-03