title: Dynamic magnetic reconnection in three space dimensions: Fan current solutions

authors: Craig, Ian J.D.

subjects: mathematics

abstract: The problem of incompressible, nonlinear magnetic reconnection in three-dimensional "open" geometries is considered. An analytic treatment shows that dynamic "fan current" reconnection may be driven by superposing long wavelength, finite amplitude, plane wave disturbances onto three-dimensional magnetic X-points. The nonlinear reconnection of the field is preceded by an advection phase in which magnetic shear waves drive large currents as they localize in the vicinity of the magnetic null. Analytic arguments, reinforced by detailed simulations, show that the ohmic dissipation rate can be independent of the plasma resistivity if the merging is suitably driven.

text: Dynamic magnetic reconnection in three space dimensions: Fan current solutions The problem of incompressible, nonlinear magnetic reconnection in three-dimensional "open" geometries is considered. An analytic treatment shows that dynamic "fan current" reconnection may be driven by superposing long wavelength, finite amplitude, plane wave disturbances onto three-dimensional magnetic X-points. The nonlinear reconnection of the field is preceded by an advection phase in which magnetic shear waves drive large currents as they localize in the vicinity of the magnetic null. Analytic arguments, reinforced by detailed simulations, show that the ohmic dissipation rate can be independent of the plasma resistivity if the merging is suitably driven.

year: 1998-03

title: Assessing hydrogen intergration in steam boilers: A comparative analysis of different energy sources for decarbonisation

authors: Weicong, Chen

subjects: Hydrogen

abstract: New Zealand has a goal to achieve carbon zero emissions by year 2050. Fossil fuels are still the main energy sources for steam boilers which are important elements in the process heat sector. Therefore, it is quite important to decarbonise the process heat sector by using low carbon energy sources, such as green hydrogen, grid sourced hydrogen, blue hydrogen, hydrogen blend, wood pellets and electricity. In this research, a comparative analysis of these energy sources is conducted to find out the difference between fuel options in terms of carbon emission reduction, conversion efficiency and the levelised cost of energy. The outcome is that wood pellet boiler system has the best performance with the lowest carbon emission factor from energy delivered to plant, high overall energy conversion efficiency, and low levelised cost of energy. Further analysis was conducted to find out how the real-time prices of grid electricity impact the levelised cost carbon emissions of energy for grid sourced hydrogen systems. It found that levelised cost of energy of grid sourced hydrogen is less than the one of natural gas boiler system, when spot electricity prices are less than 37.98 NZD/MWh with carbon price at 70 NZD/tCO2-e. Also, grid sourced hydrogen brings more carbon emissions if it is generated by using the real-time grid electricity with higher prices. The real-time carbon emissions factor and annual carbon emission factor affect the annual amount of carbon emissions and carbon costs when applied to real world case studies of steam boiler systems. The total annual amount of carbon emissions calculated using the average annual carbon emissions factor from the official source was less than that calculated by real-time carbon emission factor for the case studies considered. That would have implications for the carbon costs paid for by companies. Correlations among the electricity spot price, active lake storage and real-time carbon emissions factor of grid electricity was also found. Low carbon emissions factor of grid electricity occurred most often when the electricity spot price was low and high active lake storage level were available.

text: Assessing hydrogen intergration in steam boilers: A comparative analysis of different energy sources for decarbonisation New Zealand has a goal to achieve carbon zero emissions by year 2050. Fossil fuels are still the main energy sources for steam boilers which are important elements in the process heat sector. Therefore, it is quite important to decarbonise the process heat sector by using low carbon energy sources, such as green hydrogen, grid sourced hydrogen, blue hydrogen, hydrogen blend, wood pellets and electricity. In this research, a comparative analysis of these energy sources is conducted to find out the difference between fuel options in terms of carbon emission reduction, conversion efficiency and the levelised cost of energy. The outcome is that wood pellet boiler system has the best performance with the lowest carbon emission factor from energy delivered to plant, high overall energy conversion efficiency, and low levelised cost of energy. Further analysis was conducted to find out how the real-time prices of grid electricity impact the levelised cost carbon emissions of energy for grid sourced hydrogen systems. It found that levelised cost of energy of grid sourced hydrogen is less than the one of natural gas boiler system, when spot electricity prices are less than 37.98 NZD/MWh with carbon price at 70 NZD/tCO2-e. Also, grid sourced hydrogen brings more carbon emissions if it is generated by using the real-time grid electricity with higher prices. The real-time carbon emissions factor and annual carbon emission factor affect the annual amount of carbon emissions and carbon costs when applied to real world case studies of steam boiler systems. The total annual amount of carbon emissions calculated using the average annual carbon emissions factor from the official source was less than that calculated by real-time carbon emission factor for the case studies considered. That would have implications for the carbon costs paid for by companies. Correlations among the electricity spot price, active lake storage and real-time carbon emissions factor of grid electricity was also found. Low carbon emissions factor of grid electricity occurred most often when the electricity spot price was low and high active lake storage level were available.

year: 2024

title: Indigenous people with disabilities: The argument for representation in human rights legislation (with specific reference to the development stage of the United Nations International Disability Convention)

authors: Hickey, Huhana

subjects: Tangata whaikaha

abstract: Until comparatively recently, human rights legislation was largely based on a universalist analysis. In treating all human beings alike, in failing to acknowledge the need for special measures to combat the marginalisation and oppression of particular groups, such as indigenous people and people with disabilities, it actually contributed to their invisibility and, hence, to their marginalisation and oppression. More recently, however, there has been a global trend towards the recognition of marginalised groups in human rights legislation. Even so, universalism, and the prejudice that so often accompanies it, is still in evidence. For example, although the United Nations is currently involved in drafting a Disabled Persons Convention, indigenous people with disabilities are not specifically represented. Their particular situation, one that involves a dual form of oppression (as indigenous people and as people with disabilities) is not acknowledged. Unless this situation is remedied, the Convention will inevitably be both less acceptable and less useful than would otherwise be the case.

text: Indigenous people with disabilities: The argument for representation in human rights legislation (with specific reference to the development stage of the United Nations International Disability Convention) Until comparatively recently, human rights legislation was largely based on a universalist analysis. In treating all human beings alike, in failing to acknowledge the need for special measures to combat the marginalisation and oppression of particular groups, such as indigenous people and people with disabilities, it actually contributed to their invisibility and, hence, to their marginalisation and oppression. More recently, however, there has been a global trend towards the recognition of marginalised groups in human rights legislation. Even so, universalism, and the prejudice that so often accompanies it, is still in evidence. For example, although the United Nations is currently involved in drafting a Disabled Persons Convention, indigenous people with disabilities are not specifically represented. Their particular situation, one that involves a dual form of oppression (as indigenous people and as people with disabilities) is not acknowledged. Unless this situation is remedied, the Convention will inevitably be both less acceptable and less useful than would otherwise be the case.

year: 2005-09