title: A review of 3D/4D printing of poly-lactic acid composites with bio-derived reinforcements

authors: Muthe, Lakshmi Priya

abstract: Poly-lactic acid (PLA) has become a commonly used polymer for additive manufacturing because of its bio-derived nature, useful mechanical properties, and excellent processability. Reinforcing PLA with bio-derived materials has been shown to improve the physical, mechanical, and thermal properties of 3D printed composites and, in some cases, to produce active materials for shape-changing hygromorphic structures. PLA also displays shape memory as a response to changes in temperature, making it a popular choice for 4D printing. This review aims to present an overview of the current state of 3D/4D printing PLA composites with bio-derived reinforcements and highlight the recent progress and future opportunities. This comprehensive overview summarises the different forms of bio-derived reinforcements for PLA used in fused deposition modelling (FDM), factors influencing the resulting printed composites’ performance, and research gaps that need addressing. The current methods used before, during, and after printing to enhance the material properties and the impending need for innovative filament production and printing technologies have been brought to attention.

text: A review of 3D/4D printing of poly-lactic acid composites with bio-derived reinforcements Poly-lactic acid (PLA) has become a commonly used polymer for additive manufacturing because of its bio-derived nature, useful mechanical properties, and excellent processability. Reinforcing PLA with bio-derived materials has been shown to improve the physical, mechanical, and thermal properties of 3D printed composites and, in some cases, to produce active materials for shape-changing hygromorphic structures. PLA also displays shape memory as a response to changes in temperature, making it a popular choice for 4D printing. This review aims to present an overview of the current state of 3D/4D printing PLA composites with bio-derived reinforcements and highlight the recent progress and future opportunities. This comprehensive overview summarises the different forms of bio-derived reinforcements for PLA used in fused deposition modelling (FDM), factors influencing the resulting printed composites’ performance, and research gaps that need addressing. The current methods used before, during, and after printing to enhance the material properties and the impending need for innovative filament production and printing technologies have been brought to attention.

year: 2022

title: Re-interpreting old dates: Radiocarbon determinations from the Tokelau Islands (South Pacific)

authors: Petchey, Fiona

subjects: radiocarbon

abstract: A re-evaluation of available archaeological radiocarbon dates from the Tokelau Islands in West Polynesia demonstrates that careful assessment is essential when developing chronologies from previously published radiocarbon data. The new calibration results point to concurrent and continual human occupation of Fakaofo and Atafu from at least 750-550 years ago up until European contact in AD 1765.

text: Re-interpreting old dates: Radiocarbon determinations from the Tokelau Islands (South Pacific) A re-evaluation of available archaeological radiocarbon dates from the Tokelau Islands in West Polynesia demonstrates that careful assessment is essential when developing chronologies from previously published radiocarbon data. The new calibration results point to concurrent and continual human occupation of Fakaofo and Atafu from at least 750-550 years ago up until European contact in AD 1765.

year: 2010

title: Sylvia’s place: Ashton-Warner as New Zealand educational theorist.

authors: Middleton, Sue

subjects: educational theorist

abstract: Sylvia Ashton-Warner’s New Zealand educational context has been – and continues to be – misrepresented as antithetical to her creative methods. Sue Middleton, a professor of education, locates Sylvia’s educational ideas within the national and international Progressive Education movement, indicating that key education officials in post-war New Zealand encouraged creativity and self-expression.

This chapter makes the case that, as a teacher, an educational writer and theorist, Sylvia Ashton-Warner grew in, and not in spite of New Zealand. My argument unfolds in two parts. The first reviews theoretical ideas in the local and international educational environment in which Sylvia lived and worked. Sylvia and Keith Henderson taught in what was referred to until 1946 as the Native School system (and from 1948 until its abolition in 1968 as the Maori Scholl system). They trained and began work as teachers during the Great Depression; and Sylvia began serious writing during World War Two. The war and the Native Scholl system interested in complex ways with the wider international Progressive Education movement and its promotion ‘from the top’ in New Zealand’s public schools. An overview of Progressive (or New ) Education, the changing theories of culture and race in the Native School system, and relations between these during World War Two, opens a wide-angled aperture through which to read Sylvia’s early writing.

text: Sylvia’s place: Ashton-Warner as New Zealand educational theorist. Sylvia Ashton-Warner’s New Zealand educational context has been – and continues to be – misrepresented as antithetical to her creative methods. Sue Middleton, a professor of education, locates Sylvia’s educational ideas within the national and international Progressive Education movement, indicating that key education officials in post-war New Zealand encouraged creativity and self-expression.

This chapter makes the case that, as a teacher, an educational writer and theorist, Sylvia Ashton-Warner grew in, and not in spite of New Zealand. My argument unfolds in two parts. The first reviews theoretical ideas in the local and international educational environment in which Sylvia lived and worked. Sylvia and Keith Henderson taught in what was referred to until 1946 as the Native School system (and from 1948 until its abolition in 1968 as the Maori Scholl system). They trained and began work as teachers during the Great Depression; and Sylvia began serious writing during World War Two. The war and the Native Scholl system interested in complex ways with the wider international Progressive Education movement and its promotion ‘from the top’ in New Zealand’s public schools. An overview of Progressive (or New ) Education, the changing theories of culture and race in the Native School system, and relations between these during World War Two, opens a wide-angled aperture through which to read Sylvia’s early writing.

year: 2009