title: Everyone everywhere: A distributed and embedded paradigm for usability

authors: Twidale, Michael B.

abstract: We present a new paradigm to address the persistence of difficulties that people have in accessing and using information. Our idea consists of two main aspects: engaging wider society with usability and distributing the topic across disciplines. We claim that bad usability is a social justice issue. Primarily, we propose that usability should become the subject of widespread activism across society, enabling more people to realize that their usability problems are not due to inadequacies in themselves but in current designs. People should be encouraged and enabled to complain about their experiences with an expectation of improvements. We also propose that the current restriction of this topic to certain disciplinary units is overly narrow and that instead there should be radical embedding of usability concepts across many different fields and settings. We believe that the usability of information systems is core to information science and that information scientists should resume their historic role as heralds and pioneers of human–computer interaction.

text: Everyone everywhere: A distributed and embedded paradigm for usability We present a new paradigm to address the persistence of difficulties that people have in accessing and using information. Our idea consists of two main aspects: engaging wider society with usability and distributing the topic across disciplines. We claim that bad usability is a social justice issue. Primarily, we propose that usability should become the subject of widespread activism across society, enabling more people to realize that their usability problems are not due to inadequacies in themselves but in current designs. People should be encouraged and enabled to complain about their experiences with an expectation of improvements. We also propose that the current restriction of this topic to certain disciplinary units is overly narrow and that instead there should be radical embedding of usability concepts across many different fields and settings. We believe that the usability of information systems is core to information science and that information scientists should resume their historic role as heralds and pioneers of human–computer interaction.

year: 2021

title: Effects of activator powders on hybrid binders based on volcanic ash and portalnd clinker based cement

authors: Hettiya Kandage, Havanjana Lanka Fernando

subjects: sustainable material

abstract: Concrete remains the most widely used construction material worldwide. However, the high energy consumption and CO₂ emissions associated with Portland cement production have driven the search for more sustainable alternatives. Volcanic ash (VA), a naturally occurring pozzolan found in abundance in regions such as Tauranga, New Zealand, presents promising potential as a partial replacement for cement. 

This thesis investigates the performance of value-added products from the Takitimu North Link (TNL) site, using chemical activation with sodium sulphate (Na₂SO₄) and calcium hydroxide (Ca(OH)₂) in hybrid binder systems. A central composite experimental design was employed to systematically vary the VA content and activator dosages. 
Mortar mixes with 25%, 50%, 75%, and 100% VA replacement were tested (Series A), with particular focus on the 25% blend. This composition underwent further testing with varying activator dosages to determine the optimal Na₂SO₄/Ca(OH)₂ (NS/CH) ratio (Series B). Compressive strength tests were conducted at 7, 28, and 90 days to assess mechanical performance. 

Additionally, microstructural characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were used to identify hydration products and evaluate binder densification. 

The results showed that a 25% replacement of Portland cement with VA, activated with 14% Na₂SO₄ at an NS/CH ratio of 1, delivered optimal compressive strength and microstructural development. While higher replacement levels generally reduced early-age strength due to weaker pozzolanic activity, appropriate activator dosages improved long-term performance significantly. 

Overall, the study demonstrates that chemically activated volcanic ash can substantially improve the sustainability profile of concrete by reducing Portland cement usage and its environmental impacts. The use of optimized hybrid binders incorporating volcanic ash offers a viable solution for developing sustainable, resilient, and cost-effective construction materials in New Zealand and other volcanic regions worldwide.

text: Effects of activator powders on hybrid binders based on volcanic ash and portalnd clinker based cement Concrete remains the most widely used construction material worldwide. However, the high energy consumption and CO₂ emissions associated with Portland cement production have driven the search for more sustainable alternatives. Volcanic ash (VA), a naturally occurring pozzolan found in abundance in regions such as Tauranga, New Zealand, presents promising potential as a partial replacement for cement. 

This thesis investigates the performance of value-added products from the Takitimu North Link (TNL) site, using chemical activation with sodium sulphate (Na₂SO₄) and calcium hydroxide (Ca(OH)₂) in hybrid binder systems. A central composite experimental design was employed to systematically vary the VA content and activator dosages. 
Mortar mixes with 25%, 50%, 75%, and 100% VA replacement were tested (Series A), with particular focus on the 25% blend. This composition underwent further testing with varying activator dosages to determine the optimal Na₂SO₄/Ca(OH)₂ (NS/CH) ratio (Series B). Compressive strength tests were conducted at 7, 28, and 90 days to assess mechanical performance. 

Additionally, microstructural characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were used to identify hydration products and evaluate binder densification. 

The results showed that a 25% replacement of Portland cement with VA, activated with 14% Na₂SO₄ at an NS/CH ratio of 1, delivered optimal compressive strength and microstructural development. While higher replacement levels generally reduced early-age strength due to weaker pozzolanic activity, appropriate activator dosages improved long-term performance significantly. 

Overall, the study demonstrates that chemically activated volcanic ash can substantially improve the sustainability profile of concrete by reducing Portland cement usage and its environmental impacts. The use of optimized hybrid binders incorporating volcanic ash offers a viable solution for developing sustainable, resilient, and cost-effective construction materials in New Zealand and other volcanic regions worldwide.

year: 2025-05-08

title: The Aroha block to 1879

authors: Hart, Philip

abstract: Te Aroha was valued by Maori because of its strategic position as well as its healing hot springs, while Pakeha anticipated acquiring a large area (which shrank in size once surveyed) of fertile farming land. Before the Crown could acquire the block, the ownership of a disputed area fought over by the Marutuahu tribes (especially Ngati Maru) and Ngati Haua had to be determined. After the battle of Taumatawiwi of 1830, claimed as a victory by both sides, subsequent smaller battles continued for some years. In place of deciding ownership on this basis, the new land court struggled to make a judgment on the basis of  contradictory claims about ancestry, battles large and small, and occupation.
One part of the larger Aroha block, Ruakaka, was considered separately in 1869, resulting in the court allocating it to Ngati Haua. Also in that year, the first hearing of the Aroha Block was held, at Matamata, with the same outcome. Because of Maratuahu anger and threats of violence, Ngati Haua failed to survey the land as required, and a second hearing was held in Auckland, in 1871, at which Ngati Maru triumphed. Subsequently the block was occupied, but conflicts continued, notably when Ngati Haua gave a Pakeha permission to run cattle at Waiharakeke, further upriver. 
Starting in 1873, James Mackay slowly purchased the interests of individuals claiming ownership of the block, and paid off the Ngati Haua claimants. Then in December 1876, Ngati Tumutumu/Ngati Rahiri claimed the land for themselves, and in the following year the ownership of the Waitoki block, downstream from Te Aroha, was contested. In July 1878, a third hearing of the Aroha case commenced, resulting in Ngati Rahiri being allocated £3,000 and 7,500 acres, the remainder of the block going to Ngati Maru. Subsequently, the process of subdividing the owners’ interests proceeded, very slowly, and a small number of Pakeha settled and commenced farming or storekeeping.

text: The Aroha block to 1879 Te Aroha was valued by Maori because of its strategic position as well as its healing hot springs, while Pakeha anticipated acquiring a large area (which shrank in size once surveyed) of fertile farming land. Before the Crown could acquire the block, the ownership of a disputed area fought over by the Marutuahu tribes (especially Ngati Maru) and Ngati Haua had to be determined. After the battle of Taumatawiwi of 1830, claimed as a victory by both sides, subsequent smaller battles continued for some years. In place of deciding ownership on this basis, the new land court struggled to make a judgment on the basis of  contradictory claims about ancestry, battles large and small, and occupation.
One part of the larger Aroha block, Ruakaka, was considered separately in 1869, resulting in the court allocating it to Ngati Haua. Also in that year, the first hearing of the Aroha Block was held, at Matamata, with the same outcome. Because of Maratuahu anger and threats of violence, Ngati Haua failed to survey the land as required, and a second hearing was held in Auckland, in 1871, at which Ngati Maru triumphed. Subsequently the block was occupied, but conflicts continued, notably when Ngati Haua gave a Pakeha permission to run cattle at Waiharakeke, further upriver. 
Starting in 1873, James Mackay slowly purchased the interests of individuals claiming ownership of the block, and paid off the Ngati Haua claimants. Then in December 1876, Ngati Tumutumu/Ngati Rahiri claimed the land for themselves, and in the following year the ownership of the Waitoki block, downstream from Te Aroha, was contested. In July 1878, a third hearing of the Aroha case commenced, resulting in Ngati Rahiri being allocated £3,000 and 7,500 acres, the remainder of the block going to Ngati Maru. Subsequently, the process of subdividing the owners’ interests proceeded, very slowly, and a small number of Pakeha settled and commenced farming or storekeeping.

year: 2016