title: Influence of pumice and fines contents on the extent of particle crushing in pumiceous sand-silt mixtures during undrained cyclic triaxial loading

authors: Chaneva, Jordanka

abstract: Pumiceous particles have a distinct vesicular nature as well as a complex surface texture that makes them potentially vulnerable to crushing under cyclic loading. Pumiceous sand mixtures have received more scientific attention than pumiceous silts in this regard. Researchers have found the undrained cyclic behaviour of pumiceous sands to be significantly different from that of hard-grained sands because of the particle crushing that occurs during cyclic testing and/or sample reconstitution. The liquefaction resistance of pumiceous sands is also considered to be higher because of the pore-water pressure distribution in the sample that occurs during particle crushing. The undrained behaviour of pumiceous silt has only been studied once previously: such material did not crush during sample reconstitution and undrained cyclic testing, which was attributed to a cushioning effect taking place between silty, non-crushable particles and coarse sandy pumice particles. Whether there are thresholds of fines content and/or pumice content at which pumiceous soil mixtures start to behave more similarly to hard-grained soils are yet to be unravelled and remain relevant for engineers and scientists. This paper analyses particle crushing after sample reconstitution and undrained cyclic triaxial testing of three pumiceous natural soil mixtures (lacustrine tephra deposits) from northern New Zealand having fines (< 0.075mm) and pumice contents ranging between 20% and 70% and 30% and 51%, respectively. The results examine potential changes in (1) fines content, (2) pumice content, and (3) undrained cyclic behaviour by comparing both pore-water pressure and axial strain development of the pumiceous soils with other crushable and non-crushable soils.

text: Influence of pumice and fines contents on the extent of particle crushing in pumiceous sand-silt mixtures during undrained cyclic triaxial loading Pumiceous particles have a distinct vesicular nature as well as a complex surface texture that makes them potentially vulnerable to crushing under cyclic loading. Pumiceous sand mixtures have received more scientific attention than pumiceous silts in this regard. Researchers have found the undrained cyclic behaviour of pumiceous sands to be significantly different from that of hard-grained sands because of the particle crushing that occurs during cyclic testing and/or sample reconstitution. The liquefaction resistance of pumiceous sands is also considered to be higher because of the pore-water pressure distribution in the sample that occurs during particle crushing. The undrained behaviour of pumiceous silt has only been studied once previously: such material did not crush during sample reconstitution and undrained cyclic testing, which was attributed to a cushioning effect taking place between silty, non-crushable particles and coarse sandy pumice particles. Whether there are thresholds of fines content and/or pumice content at which pumiceous soil mixtures start to behave more similarly to hard-grained soils are yet to be unravelled and remain relevant for engineers and scientists. This paper analyses particle crushing after sample reconstitution and undrained cyclic triaxial testing of three pumiceous natural soil mixtures (lacustrine tephra deposits) from northern New Zealand having fines (< 0.075mm) and pumice contents ranging between 20% and 70% and 30% and 51%, respectively. The results examine potential changes in (1) fines content, (2) pumice content, and (3) undrained cyclic behaviour by comparing both pore-water pressure and axial strain development of the pumiceous soils with other crushable and non-crushable soils.

year: 2024-06-17

title: Discursive dissonance: Critical reflexivity for counselling supervision

authors: Esler, Ireni

subjects: supervision

abstract: When practitioners and supervisors do not share the same counselling language or theoretical orientation, how is shared meaning achieved and relational connection sustained in supervision? How are differences in theoretical orientation negotiated in supervision in ways that open space for collaborative, generative dialogue and critical reflection on the politics of practice? In response to these questions, this thesis presents a critical, reflexive practitioner-inquiry exploring the possibilities and limitations a social constructionist and narrative approach to supervision makes possible for students learning apolitical, humanistic approaches to counselling. Positioned in theoretical landscapes of social constructionism, feminist poststructuralism and Narrative Therapy, this study is a reflection-in-action of a supervisor’s practice. Central to the study’s argument is discursive positioning theory; the associated concepts of relational identity, authorship and agency; and the self as a storying subject. Two student counsellors and two newly qualified counsellors, whose practice was shaped by structuralist, humanistic theories, and who were already engaged in supervision, participated in the study. Employing narrative practices of co-inquiry to generate data, a series of supervision sessions were recorded, reviewed individually by supervisor and practitioner/participant and later discussed in reflective/research meetings. Using a critically reflexive approach to discourse analysis, selected data-texts were explored for moments of discursive dissonance and moments of movement in practice development and professional identity. Research findings highlighted the need for explicit supervision working agreements, theoretical transparency, and encouragement by counsellor training/education providers for students to make fuller use of supervision as a critical learning space. It identifies three processes that might inform supervision when theoretical orientations are non-aligned. These are: supervision as critical reflexivity, supervision as a socio-political conversation, and supervision as a storying practice.

text: Discursive dissonance: Critical reflexivity for counselling supervision When practitioners and supervisors do not share the same counselling language or theoretical orientation, how is shared meaning achieved and relational connection sustained in supervision? How are differences in theoretical orientation negotiated in supervision in ways that open space for collaborative, generative dialogue and critical reflection on the politics of practice? In response to these questions, this thesis presents a critical, reflexive practitioner-inquiry exploring the possibilities and limitations a social constructionist and narrative approach to supervision makes possible for students learning apolitical, humanistic approaches to counselling. Positioned in theoretical landscapes of social constructionism, feminist poststructuralism and Narrative Therapy, this study is a reflection-in-action of a supervisor’s practice. Central to the study’s argument is discursive positioning theory; the associated concepts of relational identity, authorship and agency; and the self as a storying subject. Two student counsellors and two newly qualified counsellors, whose practice was shaped by structuralist, humanistic theories, and who were already engaged in supervision, participated in the study. Employing narrative practices of co-inquiry to generate data, a series of supervision sessions were recorded, reviewed individually by supervisor and practitioner/participant and later discussed in reflective/research meetings. Using a critically reflexive approach to discourse analysis, selected data-texts were explored for moments of discursive dissonance and moments of movement in practice development and professional identity. Research findings highlighted the need for explicit supervision working agreements, theoretical transparency, and encouragement by counsellor training/education providers for students to make fuller use of supervision as a critical learning space. It identifies three processes that might inform supervision when theoretical orientations are non-aligned. These are: supervision as critical reflexivity, supervision as a socio-political conversation, and supervision as a storying practice.

year: 2011

title: Teachers’ perspectives on incorporating aspects of Mātauranga Māori in year 9-10 secondary school science classrooms.

authors: Hermanns, Christina Leilani

subjects: science

abstract: Science classrooms in Aotearoa New Zealand may cause some students to feel marginalised.  The inclusion of mātauranga Māori offers a diverse perspective on knowledge which may help inclusion of, and understanding for, these learners.  This research examines how science teachers include mātauranga Māori in their junior secondary science learning activities. 

I am a Pākehā teacher who was born and raised in Hawaii. I have 17 years of science teaching experience in Aotearoa New Zealand. This interpretive, phenomenographic study involved semi-structured interviews with six teachers, all who taught in North Island schools.  Five of the six participants were in schools, and one taught in a Kura Kaupapa Māori.  Data were gathered about teachers’ understanding of te reo Māori, inclusion of mātauranga Māori in the junior secondary science classroom, and how teachers’ own cultural awareness impacted their practice. 

The findings indicate that teachers include mātauranga Māori in their science classrooms in a diverse range of ways. From whole course design to more subtle ways that reflect Māori tikanga and Māori pedagogy.  Teachers often faced challenges in including mātauranga Māori in their science classroom and they overcame these by learning te reo, embracing Māori tikanga and continuing to learn to fill the gaps in their knowledge. The context of the school and its community was also a factor, as well as teachers’ personal philosophies about the nature of knowledge. 

The findings have implications for initial teacher education and professional learning for the integration of mātauranga Māori into the secondary science classroom.

text: Teachers’ perspectives on incorporating aspects of Mātauranga Māori in year 9-10 secondary school science classrooms. Science classrooms in Aotearoa New Zealand may cause some students to feel marginalised.  The inclusion of mātauranga Māori offers a diverse perspective on knowledge which may help inclusion of, and understanding for, these learners.  This research examines how science teachers include mātauranga Māori in their junior secondary science learning activities. 

I am a Pākehā teacher who was born and raised in Hawaii. I have 17 years of science teaching experience in Aotearoa New Zealand. This interpretive, phenomenographic study involved semi-structured interviews with six teachers, all who taught in North Island schools.  Five of the six participants were in schools, and one taught in a Kura Kaupapa Māori.  Data were gathered about teachers’ understanding of te reo Māori, inclusion of mātauranga Māori in the junior secondary science classroom, and how teachers’ own cultural awareness impacted their practice. 

The findings indicate that teachers include mātauranga Māori in their science classrooms in a diverse range of ways. From whole course design to more subtle ways that reflect Māori tikanga and Māori pedagogy.  Teachers often faced challenges in including mātauranga Māori in their science classroom and they overcame these by learning te reo, embracing Māori tikanga and continuing to learn to fill the gaps in their knowledge. The context of the school and its community was also a factor, as well as teachers’ personal philosophies about the nature of knowledge. 

The findings have implications for initial teacher education and professional learning for the integration of mātauranga Māori into the secondary science classroom.

year: 2025-05-29