title: Thermal stability and microhardness of Cu-10vol.%Al2O3nanocomposite produced by high energy mechanical milling

authors: Mukhtar, Aamir

subjects: Nanoscale science

abstract: Cu-10vol.%Al₂O₃ nanocomposite powders were produced using two high energy milling routes and heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the microstructure and the micohardness change of the materials as a function of the annealing temperature. Annealing of the as-milled powders at 150°C caused recovery and recrystallisation that leads to significant decrease in dislocation density and slight decrease of microhardness. Increasing the annealing temperature to 400°C causes slight coarsening of the Cu grains and corresponding slight decrease of microhardness. Further increasing the annealing temperature to 500°C causes significant coarsening of the Cu grains and cause significant decrease in microhardness. The effects of different factors on the thermal stability and micohardness change of the Cu- Al₂O₃  are discussed.

text: Thermal stability and microhardness of Cu-10vol.%Al2O3nanocomposite produced by high energy mechanical milling Cu-10vol.%Al₂O₃ nanocomposite powders were produced using two high energy milling routes and heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the microstructure and the micohardness change of the materials as a function of the annealing temperature. Annealing of the as-milled powders at 150°C caused recovery and recrystallisation that leads to significant decrease in dislocation density and slight decrease of microhardness. Increasing the annealing temperature to 400°C causes slight coarsening of the Cu grains and corresponding slight decrease of microhardness. Further increasing the annealing temperature to 500°C causes significant coarsening of the Cu grains and cause significant decrease in microhardness. The effects of different factors on the thermal stability and micohardness change of the Cu- Al₂O₃  are discussed.

year: 2010

title: Book review: Ecological Restoration

authors: Clarkson, Bruce D.

subjects: book review

abstract: This article reviews the book “Ecological Restoration”, by Susan M. Galatowitsch.

text: Book review: Ecological Restoration This article reviews the book “Ecological Restoration”, by Susan M. Galatowitsch.

year: 2013

title: Maori and mining in New Zealand and beyond

authors: Hart, Philip

abstract: Before the arrival of Europeans, Maori had known of the existence of gold but did not mine it and had no understanding of its value. Once mining commenced in California in 1849 and Australia in the early 1850s, many Maori participated on several fields, especially in Victoria. When gold was first discovered in New Zealand, at Coromandel in 1852, Maori were keen to learn prospecting skills, and soon found gold in several parts of both the North and South Islands. Some alluvial claims were worked communally, even some women participating. From the start, Maori were determined to protect their rights against Pakeha when they were rivals for the same ground.  
On the Hauraki Peninsula, which had no alluvial gold, Maori were prospectors rather than miners. Some were successful, often going against the wishes of rangatira who, fearing that opening goldfields would result in their losing their land, refused access to prospectors, particularly in Ohinemuri. At Thames, Maori prospectors succeeded where Pakeha ones had failed, finding the gold that led to the 1867 rush; a rush encouraged by one rangatira in particular, Wirope Hoterene Taipari, who understood how a successful field would benefit him financially (including obtaining a reward for discovering a payable goldfield). After the opening of this field, some Maori prospected throughout the peninsula and elsewhere for the remainder of the century, with varying success but with some good finds, particularly at Kuaotunu. A few even participated in the Klondike rush. By the twentieth century, Maori were overcoming their reluctance to mine underground, notably in the coalmines of the Waikato, but until then almost none had seen mining as a full-time career. 
Indigenous inhabitants throughout the world successfully prospected for precious metals, but their achievements were commonly written out of history, as for example in Australia, where Aboriginal involvement is only now being uncovered. In New Zealand also, Maori achievements, although well known to contemporaries, have largely been forgotten. At the time, Maori prospector’s successes were praised and many became owners of claims, and in some cases benefited financially from their involvement in mining.

text: Maori and mining in New Zealand and beyond Before the arrival of Europeans, Maori had known of the existence of gold but did not mine it and had no understanding of its value. Once mining commenced in California in 1849 and Australia in the early 1850s, many Maori participated on several fields, especially in Victoria. When gold was first discovered in New Zealand, at Coromandel in 1852, Maori were keen to learn prospecting skills, and soon found gold in several parts of both the North and South Islands. Some alluvial claims were worked communally, even some women participating. From the start, Maori were determined to protect their rights against Pakeha when they were rivals for the same ground.  
On the Hauraki Peninsula, which had no alluvial gold, Maori were prospectors rather than miners. Some were successful, often going against the wishes of rangatira who, fearing that opening goldfields would result in their losing their land, refused access to prospectors, particularly in Ohinemuri. At Thames, Maori prospectors succeeded where Pakeha ones had failed, finding the gold that led to the 1867 rush; a rush encouraged by one rangatira in particular, Wirope Hoterene Taipari, who understood how a successful field would benefit him financially (including obtaining a reward for discovering a payable goldfield). After the opening of this field, some Maori prospected throughout the peninsula and elsewhere for the remainder of the century, with varying success but with some good finds, particularly at Kuaotunu. A few even participated in the Klondike rush. By the twentieth century, Maori were overcoming their reluctance to mine underground, notably in the coalmines of the Waikato, but until then almost none had seen mining as a full-time career. 
Indigenous inhabitants throughout the world successfully prospected for precious metals, but their achievements were commonly written out of history, as for example in Australia, where Aboriginal involvement is only now being uncovered. In New Zealand also, Maori achievements, although well known to contemporaries, have largely been forgotten. At the time, Maori prospector’s successes were praised and many became owners of claims, and in some cases benefited financially from their involvement in mining.

year: 2016