title: Plasticizer migration in bloodmeal-based thermoplastics

authors: Bier, James Michael

subjects: biopolymers and renewable polymersplasticizer

abstract: Tri-ethylene glycol (TEG) is an effective plasticizer for many protein-based thermoplastics because of its low volatility, however, partial miscibility with the protein matrix may still lead to some phase separation. Spatial variation of TEG concentration in bloodmeal-based thermoplastics as a result of processing was investigated using synchrotron-based FT-IR micro-spectroscopy. Although TEG forms strong hydrogen bonding with proteins, for the protein to fold into β-sheets bound plasticizer must be released. TEG can then migrate, pooling into localized areas, rich in plasticizer. Further heating causes further migration towards the edge of plasticized bloodmeal particles where the TEG may evaporate. Thermo-gravimetric analysis confirmed that loss of TEG by evaporation may occur at 120°C, given enough time for diffusion. Efficient mixing combined with a short residence time at elevated temperature mean significant plasticizer loss is unlikely during processing. However, it does limit long-term use at elevated temperatures.

text: Plasticizer migration in bloodmeal-based thermoplastics Tri-ethylene glycol (TEG) is an effective plasticizer for many protein-based thermoplastics because of its low volatility, however, partial miscibility with the protein matrix may still lead to some phase separation. Spatial variation of TEG concentration in bloodmeal-based thermoplastics as a result of processing was investigated using synchrotron-based FT-IR micro-spectroscopy. Although TEG forms strong hydrogen bonding with proteins, for the protein to fold into β-sheets bound plasticizer must be released. TEG can then migrate, pooling into localized areas, rich in plasticizer. Further heating causes further migration towards the edge of plasticized bloodmeal particles where the TEG may evaporate. Thermo-gravimetric analysis confirmed that loss of TEG by evaporation may occur at 120°C, given enough time for diffusion. Efficient mixing combined with a short residence time at elevated temperature mean significant plasticizer loss is unlikely during processing. However, it does limit long-term use at elevated temperatures.

year: 2013

title: Legacies of learning: Negotiating guidelines for online discussion

authors: Forbes, Dianne Leslie

subjects: Asynchronous Online Discussion

abstract: This study involves students in constructing a community resource or legacy for future learners to use. In this instance, the resource takes the form of a set of guidelines for Asynchronous Online Discussion (AOD). Working within Moodle, teacher education students negotiated and revised sets of AOD guidelines for use in their own class, and to provide as a legacy for a future class. Data were generated over two semesters by consecutive cohorts of students. The findings highlight some key expectations that students set for peers when learning through AOD, such as a preference for accurate and responsive postings. It is also apparent that students appreciate and value the opportunity to negotiate guidelines. In terms of digital smarts, this study promotes effective use of AOD as an accessible means of engaging students in dialogue and deep learning. It is smart to negotiate guidelines for AOD with students so that expectations are clear, student perspectives are respected and opportunities to contribute to others’ learning are provided.

text: Legacies of learning: Negotiating guidelines for online discussion This study involves students in constructing a community resource or legacy for future learners to use. In this instance, the resource takes the form of a set of guidelines for Asynchronous Online Discussion (AOD). Working within Moodle, teacher education students negotiated and revised sets of AOD guidelines for use in their own class, and to provide as a legacy for a future class. Data were generated over two semesters by consecutive cohorts of students. The findings highlight some key expectations that students set for peers when learning through AOD, such as a preference for accurate and responsive postings. It is also apparent that students appreciate and value the opportunity to negotiate guidelines. In terms of digital smarts, this study promotes effective use of AOD as an accessible means of engaging students in dialogue and deep learning. It is smart to negotiate guidelines for AOD with students so that expectations are clear, student perspectives are respected and opportunities to contribute to others’ learning are provided.

year: 2015

title: Te Pūtahitanga: A Tiriti-led science-policy approach for Aotearoa New Zealand

authors: Kukutai, Tahu

abstract: This paper examines the interface between science and policymaking and calls for a policy approach that is enabled by, and responsive to, Te Tiriti o Waitangi and Mātauranga Māori. For a science sector to have its greatest reach and impact for all citizens, it must demonstrate relevance, accessibility and inclusion. In Aotearoa, there has been concern about the exclusion of Māori and Pacific expertise from science advice and key decision-making roles. Te Tiriti offers a powerful framework for connecting systems and communities of knowledge in ways that are mutually beneficial and future focused.

text: Te Pūtahitanga: A Tiriti-led science-policy approach for Aotearoa New Zealand This paper examines the interface between science and policymaking and calls for a policy approach that is enabled by, and responsive to, Te Tiriti o Waitangi and Mātauranga Māori. For a science sector to have its greatest reach and impact for all citizens, it must demonstrate relevance, accessibility and inclusion. In Aotearoa, there has been concern about the exclusion of Māori and Pacific expertise from science advice and key decision-making roles. Te Tiriti offers a powerful framework for connecting systems and communities of knowledge in ways that are mutually beneficial and future focused.

year: 2021-04-28