title: Effect of spark plasma sintering temperature on microstructure and mechanical properties of an ultrafine grained TiAl intermetallic alloy

authors: Chen, Yuyong

subjects: spark plasma sintering

abstract: The effect of spark plasma sintering (SPS) temperature on the microstructure and mechanical properties of a bulk solid ultrafine grained gamma TiAl alloy produced by SPS of an ultrafine structured Ti/Al composite powder with a nominal composition of Ti–47 at.%Al has been investigated. The Ti/Al composite powder was produced using high energy mechanical milling. It was found that an SPS temperature of 800 °C led to the completion of the reactions needed for reaching the phase equilibrium and formation of a nanostructure with grain sizes in the range of 50–100 nm. However, this SPS temperature was not sufficient to achieve a nearly full density of the compact or a high level of interparticle bonding. Increasing the SPS temperature from 800 to 900 °C caused a significant increase of the density and the level of interparticle bonding while still maintaining grain sizes of <500 nm. The bulk TiAl alloy produced under this condition had a good compression yield strength, fracture strength, bending strength and plastic strain to fracture of 1722, 1963, 610 MPa and 4%, respectively. Increasing the SPS temperature from 900 to 1100 °C caused significant coarsening of the TiAl grains which led to a clear decrease in yield strength and hardness and a slight increase in ductility.

text: Effect of spark plasma sintering temperature on microstructure and mechanical properties of an ultrafine grained TiAl intermetallic alloy The effect of spark plasma sintering (SPS) temperature on the microstructure and mechanical properties of a bulk solid ultrafine grained gamma TiAl alloy produced by SPS of an ultrafine structured Ti/Al composite powder with a nominal composition of Ti–47 at.%Al has been investigated. The Ti/Al composite powder was produced using high energy mechanical milling. It was found that an SPS temperature of 800 °C led to the completion of the reactions needed for reaching the phase equilibrium and formation of a nanostructure with grain sizes in the range of 50–100 nm. However, this SPS temperature was not sufficient to achieve a nearly full density of the compact or a high level of interparticle bonding. Increasing the SPS temperature from 800 to 900 °C caused a significant increase of the density and the level of interparticle bonding while still maintaining grain sizes of <500 nm. The bulk TiAl alloy produced under this condition had a good compression yield strength, fracture strength, bending strength and plastic strain to fracture of 1722, 1963, 610 MPa and 4%, respectively. Increasing the SPS temperature from 900 to 1100 °C caused significant coarsening of the TiAl grains which led to a clear decrease in yield strength and hardness and a slight increase in ductility.

year: 2009

title: Singing 'A Tune Beyond Ourselves': An Investigation into the Diverse Voices of Childhood and Poetry

authors: Masters, Caroline J.

subjects: Childhood

abstract: Over the past 300 years the ‘World of Children’ has evolved and along with it so has poetry written for, and about, children. This thesis focuses on the poetic portrayal of children in Great Britain from 1715 to 1885, specifically the virtues which adults have deemed necessary, ‘desirable, attractive, or interesting in the young’.   The poets I discuss — Isaac Watts, William Blake, Charles and Mary Lamb, Charlotte Smith, Anna Laetitia Barbauld, William Wordsworth, Lewis Carroll, Edward Lear, and Robert Louis Stevenson— either view children as little adults, adults in training, or rebel against adult interference in children’s lives. All of the poets strive to protect and advance a particular concept of childhood.
	The recent scholarship of critics such as Nancy Taylor Coghill, Norejane J. Henrickson, and Mitzi Myers has shown that as the canon of children’s literature has evolved, a progression away from didacticism towards imagination and ‘fun’ is apparent, with the latter being preferred. This thesis explores whether the apparent division of poetry for, and about, children is as clear cut as this.
	Throughout, I argue that the history of childhood and poetry is variegated and that creativity has not ousted didacticism over time. Instead the two currents have at times co-existed, been merged, or blended with other approaches.

text: Singing 'A Tune Beyond Ourselves': An Investigation into the Diverse Voices of Childhood and Poetry Over the past 300 years the ‘World of Children’ has evolved and along with it so has poetry written for, and about, children. This thesis focuses on the poetic portrayal of children in Great Britain from 1715 to 1885, specifically the virtues which adults have deemed necessary, ‘desirable, attractive, or interesting in the young’.   The poets I discuss — Isaac Watts, William Blake, Charles and Mary Lamb, Charlotte Smith, Anna Laetitia Barbauld, William Wordsworth, Lewis Carroll, Edward Lear, and Robert Louis Stevenson— either view children as little adults, adults in training, or rebel against adult interference in children’s lives. All of the poets strive to protect and advance a particular concept of childhood.
	The recent scholarship of critics such as Nancy Taylor Coghill, Norejane J. Henrickson, and Mitzi Myers has shown that as the canon of children’s literature has evolved, a progression away from didacticism towards imagination and ‘fun’ is apparent, with the latter being preferred. This thesis explores whether the apparent division of poetry for, and about, children is as clear cut as this.
	Throughout, I argue that the history of childhood and poetry is variegated and that creativity has not ousted didacticism over time. Instead the two currents have at times co-existed, been merged, or blended with other approaches.

year: 2015

title: Food insecurity in urban New Zealand. The case of the Kopa family

authors: Graham, Rebekah Sarah

abstract: Poverty brings insecurity and chaos into the home, forcing families to develop strategies for navigating the difficulties of food insecurity. We document how one household, the Kopa family, responds to poverty in ad hoc and agentive ways that assist and hinder their attempts to keep themselves fed. This study is based on a series of eight qualitative interviews with family members, including photo-elicitation and go-along techniques, as well as extensive field notes from more casual research interactions such as shared meals. Our analysis demonstrates how food insecurity shapes this family’s culturally patterned social practices surrounding the procurement, consumption, and sharing of food.

text: Food insecurity in urban New Zealand. The case of the Kopa family Poverty brings insecurity and chaos into the home, forcing families to develop strategies for navigating the difficulties of food insecurity. We document how one household, the Kopa family, responds to poverty in ad hoc and agentive ways that assist and hinder their attempts to keep themselves fed. This study is based on a series of eight qualitative interviews with family members, including photo-elicitation and go-along techniques, as well as extensive field notes from more casual research interactions such as shared meals. Our analysis demonstrates how food insecurity shapes this family’s culturally patterned social practices surrounding the procurement, consumption, and sharing of food.

year: 2018