title: Curing kinetics and effects of fibre surface treatment and curing parameters on the interfacial and tensile properties of hemp/epoxy composites

authors: Islam, Mohammad Saiful

subjects: hemp fibre

abstract: The curing kinetics of neat epoxy (NE) and hemp fibre/epoxy composites was studied and assessed using two dynamic models (the Kissinger and Flynn-Wall-Ozawa Models) and an isothermal model (the Autocatalytic Model) which was generally supported by the experimental data obtained from dynamic and isothermal differential scanning calorimetry (DSC) scans. The activation energies for the curing of composites exhibited lower values compared to curing of NE which is believed to be due to higher nucleophilic activity of the amine groups of the curing agent in the presence of fibres. The highest tensile strength, σ was obtained with composites produced with an epoxy to curing agent ratio of 1:1 and the highest Young's modulus, E was obtained with an epoxy to curing agent ratio of 1:1.2. Alkali treated hemp fibre/epoxy (ATFE) composites were found to have higher σ and E values compared to those for untreated hemp fibre/epoxy (UTFE) composites which was consistent with the trend for interfacial shear strength (IFSS) values. Composites σ and E were found to be higher for a processing temperature of 70°C than for 25°C for both UTFE and ATFE composites, but were found to decrease as the curing temperature was increased further to 120°C.

text: Curing kinetics and effects of fibre surface treatment and curing parameters on the interfacial and tensile properties of hemp/epoxy composites The curing kinetics of neat epoxy (NE) and hemp fibre/epoxy composites was studied and assessed using two dynamic models (the Kissinger and Flynn-Wall-Ozawa Models) and an isothermal model (the Autocatalytic Model) which was generally supported by the experimental data obtained from dynamic and isothermal differential scanning calorimetry (DSC) scans. The activation energies for the curing of composites exhibited lower values compared to curing of NE which is believed to be due to higher nucleophilic activity of the amine groups of the curing agent in the presence of fibres. The highest tensile strength, σ was obtained with composites produced with an epoxy to curing agent ratio of 1:1 and the highest Young's modulus, E was obtained with an epoxy to curing agent ratio of 1:1.2. Alkali treated hemp fibre/epoxy (ATFE) composites were found to have higher σ and E values compared to those for untreated hemp fibre/epoxy (UTFE) composites which was consistent with the trend for interfacial shear strength (IFSS) values. Composites σ and E were found to be higher for a processing temperature of 70°C than for 25°C for both UTFE and ATFE composites, but were found to decrease as the curing temperature was increased further to 120°C.

year: 2009

title: Question-asking and question-exploring

authors: Sands, Lorraine May

subjects: agency

abstract: The Centre of Innovation Research at Greerton Early Childhood Centre was characterised as a dispositional milieu where working theories were explored through a narrative research methodology. As the research progressed, the teachers at Greerton strengthened the way we were listening to, and watching out for young children's questions to enable them to become deeply involved in exploring the world around them. The key question for this research was: How does a 'question-asking' and a 'question-exploring' culture support children to develop working theories to shape and re-shape knowledge for a purpose? Given our work with Te Whāriki (1996), we have always seen teaching and learning as being about reciprocal relationships with people, places and things and the context being crucial, and continuity as the intention of story. In this project, by combining narrative inquiry with action research in an early childhood centre in Aotearoa New Zealand, we have developed a frame of 'commitments' that go beyond those that might be for narrative inquiry on its own. Four aspects have been woven into the narrative inquiry: continuity as the 'linchpin' of our work, agency (issues of power), an innovative conceptualising of the connection with community, and the central role of affect or emotion in learning.

text: Question-asking and question-exploring The Centre of Innovation Research at Greerton Early Childhood Centre was characterised as a dispositional milieu where working theories were explored through a narrative research methodology. As the research progressed, the teachers at Greerton strengthened the way we were listening to, and watching out for young children's questions to enable them to become deeply involved in exploring the world around them. The key question for this research was: How does a 'question-asking' and a 'question-exploring' culture support children to develop working theories to shape and re-shape knowledge for a purpose? Given our work with Te Whāriki (1996), we have always seen teaching and learning as being about reciprocal relationships with people, places and things and the context being crucial, and continuity as the intention of story. In this project, by combining narrative inquiry with action research in an early childhood centre in Aotearoa New Zealand, we have developed a frame of 'commitments' that go beyond those that might be for narrative inquiry on its own. Four aspects have been woven into the narrative inquiry: continuity as the 'linchpin' of our work, agency (issues of power), an innovative conceptualising of the connection with community, and the central role of affect or emotion in learning.

year: 2012

title: Re-designing the national imaginary: The development of Matariki as a contemporary festival

authors: Hardy, Ann

subjects: Aotearoa/New Zealand

abstract: This article considers the factors shaping the contemporary redevelopment in Aotearoa/ New Zealand of the indigenous commemoration of the rising of the constellation Matariki as a marker of seasonal change.  Through interviews with producers of media materials celebrating Matariki, it examines the ideological, cultural, and economic factors determining the encoding of the materials, investigating in particular the ways in which Matariki can resource a marketplace for spiritual commodities.

text: Re-designing the national imaginary: The development of Matariki as a contemporary festival This article considers the factors shaping the contemporary redevelopment in Aotearoa/ New Zealand of the indigenous commemoration of the rising of the constellation Matariki as a marker of seasonal change.  Through interviews with producers of media materials celebrating Matariki, it examines the ideological, cultural, and economic factors determining the encoding of the materials, investigating in particular the ways in which Matariki can resource a marketplace for spiritual commodities.

year: 2012