title: Direct extrusion 3D printing for a softer PLA-based bio-polymer composite in pellet form

authors: Singamneni, Sarat

subjects: polymer composite

abstract: Fused deposition modelling is the most popular method of 3D printing with a variety of polymers, but the raw materials are commonly in the filament form. Research has demonstrated the ability to use pellets for this process, which are easier to produce than filaments. Apart from the savings on the pre-processing, the approach also combines the good attributes of both injection moulding and 3D printing and referred to as extrusion 3D printing. Direct printing of pellets is especially suited for thermosensitive polymers, with which, repeated or excessive heating may lead to degeneration. Also, polymers that are too soft do not qualify for filament-based extrusion. PLA is a popular choice for fused deposition modelling in the filament form but is often too brittle. A softer version of PLA composite based on PBAT and cellulose fibres is proposed here for 3D printing. Considering the lack of stiffness of the filaments, direct extrusion from pellet form is evaluated. Regardless of form, the polymer material system satisfied the stringent conditions of consolidation as dictated by the dynamic combination of extrusion and rasterised material deposition. Experimental evaluation based on meso-structural and mechanical property analyses indicate the new pellet-based material system to be suitable and to perform well. The novelty of the material and process combination is that the printed samples were actually comparable mechanically to the injection moulded counterparts, which is an extraordinary achievement, considering the shortcomings typical of material consolidation in additive manufacturing.

text: Direct extrusion 3D printing for a softer PLA-based bio-polymer composite in pellet form Fused deposition modelling is the most popular method of 3D printing with a variety of polymers, but the raw materials are commonly in the filament form. Research has demonstrated the ability to use pellets for this process, which are easier to produce than filaments. Apart from the savings on the pre-processing, the approach also combines the good attributes of both injection moulding and 3D printing and referred to as extrusion 3D printing. Direct printing of pellets is especially suited for thermosensitive polymers, with which, repeated or excessive heating may lead to degeneration. Also, polymers that are too soft do not qualify for filament-based extrusion. PLA is a popular choice for fused deposition modelling in the filament form but is often too brittle. A softer version of PLA composite based on PBAT and cellulose fibres is proposed here for 3D printing. Considering the lack of stiffness of the filaments, direct extrusion from pellet form is evaluated. Regardless of form, the polymer material system satisfied the stringent conditions of consolidation as dictated by the dynamic combination of extrusion and rasterised material deposition. Experimental evaluation based on meso-structural and mechanical property analyses indicate the new pellet-based material system to be suitable and to perform well. The novelty of the material and process combination is that the printed samples were actually comparable mechanically to the injection moulded counterparts, which is an extraordinary achievement, considering the shortcomings typical of material consolidation in additive manufacturing.

year: 2021

title: Laptops for teachers: practices and possibilities

authors: Cowie, Bronwen

subjects: teachers’ laptops

abstract: The Laptops for Teachers scheme in New Zealand provides teachers whose schools opt into the scheme access to a laptop for their exclusive use. This paper reports on the findings of the three‐year evaluation of the impact of the laptops on secondary teachers’ work. The findings indicate that school leadership has been pivotal to the provision of the technological infrastructure and organisational support needed for teacher use of the laptops. Departmental leadership has been crucial in supporting teacher use of laptops for teaching and learning. Teachers described gains in expertise, indicating that they used the laptop for a range of purposes to support their teaching. These included lesson planning and preparation, and reporting. Where teachers had easy access to a laptop‐plus‐data projector they found that students responded to material that included images and up‐to‐date real‐world examples. Colleagues were identified as the main source of professional development for the use of the laptop for teaching purposes. The findings of the study suggest schools are advised to consider how to support teachers to work collaboratively to share expertise as a way of supporting and extending teacher use of laptops.

text: Laptops for teachers: practices and possibilities The Laptops for Teachers scheme in New Zealand provides teachers whose schools opt into the scheme access to a laptop for their exclusive use. This paper reports on the findings of the three‐year evaluation of the impact of the laptops on secondary teachers’ work. The findings indicate that school leadership has been pivotal to the provision of the technological infrastructure and organisational support needed for teacher use of the laptops. Departmental leadership has been crucial in supporting teacher use of laptops for teaching and learning. Teachers described gains in expertise, indicating that they used the laptop for a range of purposes to support their teaching. These included lesson planning and preparation, and reporting. Where teachers had easy access to a laptop‐plus‐data projector they found that students responded to material that included images and up‐to‐date real‐world examples. Colleagues were identified as the main source of professional development for the use of the laptop for teaching purposes. The findings of the study suggest schools are advised to consider how to support teachers to work collaboratively to share expertise as a way of supporting and extending teacher use of laptops.

year: 2011

title: Keeping Chooks at Home in the Waikato:  Exploring Postcolonial, Feminist and  Kaupapa M ori Perspectives

authors: Burnett, Zavier

subjects: Chooks

abstract: This thesis considers the narratives of eight M ori chook keepers from the Waikato rohe, Aotearoa. The Waikato rohe has been selected due to its significant history of M ori horticultural and agricultural practises, including chook keeping. 

I build on the growing corpus of m tauranga about indigenous studies. Using a postcolonial, feminist and Kaupapa M ori theoretical framework, I undertook five semi-structured interviews and one focus r p  with M ori kaum tua. This thesis does not attempt to represent all M ori. There may be considerable difference between wh nau, hap  and iwi practices. However, the rangahau provides insights into the views of eight individuals and their experiences with chooks. I have also utilised Country Calendar (1970; 1977a; 1977b and 1980) episodes and children's pukapuka such as Nanny Mihi's Garden (Drewery 2002) for the purposes of discourse analysis. 

By listening to these stories, kaupapa including race, class and ethnicity emerge that affect the participants' everyday lives as chook keepers. The participants view chooks in a variety of ways. First, as a means of food production. By integrating chooks into their communities, the participants are able to provide a nutritious and low-cost kai source for themselves and their wh nau. This attempts to at least in part address their poverty problems. Second, as a hybridised P keh  and M ori kararehe. Third, as hysterical, comical, silly and helpless. I explore these issues within the broader context of colonial, neocolonial and anticolonial practices.

text: Keeping Chooks at Home in the Waikato:  Exploring Postcolonial, Feminist and  Kaupapa M ori Perspectives This thesis considers the narratives of eight M ori chook keepers from the Waikato rohe, Aotearoa. The Waikato rohe has been selected due to its significant history of M ori horticultural and agricultural practises, including chook keeping. 

I build on the growing corpus of m tauranga about indigenous studies. Using a postcolonial, feminist and Kaupapa M ori theoretical framework, I undertook five semi-structured interviews and one focus r p  with M ori kaum tua. This thesis does not attempt to represent all M ori. There may be considerable difference between wh nau, hap  and iwi practices. However, the rangahau provides insights into the views of eight individuals and their experiences with chooks. I have also utilised Country Calendar (1970; 1977a; 1977b and 1980) episodes and children's pukapuka such as Nanny Mihi's Garden (Drewery 2002) for the purposes of discourse analysis. 

By listening to these stories, kaupapa including race, class and ethnicity emerge that affect the participants' everyday lives as chook keepers. The participants view chooks in a variety of ways. First, as a means of food production. By integrating chooks into their communities, the participants are able to provide a nutritious and low-cost kai source for themselves and their wh nau. This attempts to at least in part address their poverty problems. Second, as a hybridised P keh  and M ori kararehe. Third, as hysterical, comical, silly and helpless. I explore these issues within the broader context of colonial, neocolonial and anticolonial practices.

year: 2006