title: Synthesis and thermal stability of Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powders by high energy mechanical milling

authors: Zhang, Deliang

subjects: mechanical milling

abstract: High energy mechanical milling (HEMM) of a mixture of Cu powder and Al₂O₃ nanopowder has been used to produce Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powders with a ultrafine grained or nanocrystalline Cu matrix. The microstructure and microhardness of the as-milled powder particles and the thermal stability and microhardness change of the nanocomposite powder particles caused by annealing at temperatures up to 500oC have been studied. It is shown that HEMM can be effectively used to disperse (2.5-10)vol.% Al₂O₃ nanoparticles into a ultrafine grained or nanocrystalline Cu matrix. Using larger diameter balls or increasing the volume fraction of Al₂O₃ nanoparticles to 7.5% or higher allows synthesis of Cu-Al₂O₃ nanocomposite powders with nanocrystalline Cu matrix. Refining the microstructure of the Cu matrix and increasing the volume fraction of Al₂O₃ nanoparticles in the nanocomposite both increase the thermal stability of the nanocomposite structure.

text: Synthesis and thermal stability of Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powders by high energy mechanical milling High energy mechanical milling (HEMM) of a mixture of Cu powder and Al₂O₃ nanopowder has been used to produce Cu-(2.5-10)vol.%Al₂O₃ nanocomposite powders with a ultrafine grained or nanocrystalline Cu matrix. The microstructure and microhardness of the as-milled powder particles and the thermal stability and microhardness change of the nanocomposite powder particles caused by annealing at temperatures up to 500oC have been studied. It is shown that HEMM can be effectively used to disperse (2.5-10)vol.% Al₂O₃ nanoparticles into a ultrafine grained or nanocrystalline Cu matrix. Using larger diameter balls or increasing the volume fraction of Al₂O₃ nanoparticles to 7.5% or higher allows synthesis of Cu-Al₂O₃ nanocomposite powders with nanocrystalline Cu matrix. Refining the microstructure of the Cu matrix and increasing the volume fraction of Al₂O₃ nanoparticles in the nanocomposite both increase the thermal stability of the nanocomposite structure.

year: 2009

title: Classifying landscape character

authors: Brabyn, Lars

subjects: visual

abstract: Landscape classification is fundamental to landscape management and research because it provides a frame of reference for communication. This paper describes a method for classifying visual landscape character in New Zealand and builds on a previously developed method using Geographical Information Systems. Theoretical issues associated with classifying landscapes are discussed and incorporated into the method. The main components of the classification are landform, landcover, water, infrastructure, dominant landcover and water view. The resulting classification is hierarchical, with six levels of generalisation. A naturalness score is also built into the classification. Applications of the classification are briefly described. These included query and identification of similar landscapes, description and landscape inventory of regions, identifying rare and unique landscapes, and combining with visibility analysis to describe landscape experience on walking tracks. The New Zealand Landscape Classification is designed to complement other landscape information such as the location of historical, spiritual, cultural, and geological landscape features.

text: Classifying landscape character Landscape classification is fundamental to landscape management and research because it provides a frame of reference for communication. This paper describes a method for classifying visual landscape character in New Zealand and builds on a previously developed method using Geographical Information Systems. Theoretical issues associated with classifying landscapes are discussed and incorporated into the method. The main components of the classification are landform, landcover, water, infrastructure, dominant landcover and water view. The resulting classification is hierarchical, with six levels of generalisation. A naturalness score is also built into the classification. Applications of the classification are briefly described. These included query and identification of similar landscapes, description and landscape inventory of regions, identifying rare and unique landscapes, and combining with visibility analysis to describe landscape experience on walking tracks. The New Zealand Landscape Classification is designed to complement other landscape information such as the location of historical, spiritual, cultural, and geological landscape features.

year: 2009

title: Media psychology, symbolic power and social justice in Aotearoa

authors: Hodgetts, Darrin

subjects: media

abstract: Psychologists reside in a world saturated by media. We work in professional contexts where guidelines for practice foreground ethical obligations to address issues of social justice. This paper addresses both these contextual dimensions of psychological research and practice. We explore the social significance of increased media production by Maori in challenging the tendency in mainstream media to marginalize Maori concerns while promoting Pakeha perspectives. The analysis focuses on the recent 'Inside Out documentary - Hikoi', which was initiated by two young Maori women as a challenge to media framing of Maori protests as 'unjustified' and 'disruptive' acts. We illustrate how this documentary furthers public dialogue regarding the foreshore and seabed controversy by promoting an alternative depiction of a Maori protest, which emphasize the history of grievances and social unity. The implications of such representations for psychologists working to address issues of social justice and to challenge abuses of symbolic power are discussed.

text: Media psychology, symbolic power and social justice in Aotearoa Psychologists reside in a world saturated by media. We work in professional contexts where guidelines for practice foreground ethical obligations to address issues of social justice. This paper addresses both these contextual dimensions of psychological research and practice. We explore the social significance of increased media production by Maori in challenging the tendency in mainstream media to marginalize Maori concerns while promoting Pakeha perspectives. The analysis focuses on the recent 'Inside Out documentary - Hikoi', which was initiated by two young Maori women as a challenge to media framing of Maori protests as 'unjustified' and 'disruptive' acts. We illustrate how this documentary furthers public dialogue regarding the foreshore and seabed controversy by promoting an alternative depiction of a Maori protest, which emphasize the history of grievances and social unity. The implications of such representations for psychologists working to address issues of social justice and to challenge abuses of symbolic power are discussed.

year: 2004-11-19