title: Influence of hygrothermal ageing on the physico-mechanical properties of alkali treated industrial hemp fibre reinforced polylactic acid composites

authors: Islam, Mohammad Saiful

subjects: hemp fibre

abstract: 30 wt% aligned untreated long hemp fibre/polylactic acid (AUL) and aligned alkali treated long hemp fibre/polylactic acid (AAL) composites were produced by film stacking and subjected to hygrothermal ageing environment along with neat polylactic acid (PLA). Hygrothermal ageing was carried out by immersing samples in distilled water at 25 and 50 ºC over a period of 3 months. It was found that both neat PLA and composites followed Fickian diffusion. Higher temperature generally increased the Diffusion coefficient, D of neat PLA and composites, as well as shortening the saturation time. Neat PLA had the lowest D value followed by AAL composites and then AUL composites. After hygrothermal ageing, tensile and flexural strength, Young’s and flexural modulus and KIc were found to decrease and impact strength was found to increase for both AUL and AAL composites. AUL composites had greater overall reduction in mechanical properties than that for AAL composites after hygrothermal ageing. Crystallinity contents of the hygrothermal aged composites support the results of the deterioration of mechanical properties upon exposure to hygrothermal ageing environment.

text: Influence of hygrothermal ageing on the physico-mechanical properties of alkali treated industrial hemp fibre reinforced polylactic acid composites 30 wt% aligned untreated long hemp fibre/polylactic acid (AUL) and aligned alkali treated long hemp fibre/polylactic acid (AAL) composites were produced by film stacking and subjected to hygrothermal ageing environment along with neat polylactic acid (PLA). Hygrothermal ageing was carried out by immersing samples in distilled water at 25 and 50 ºC over a period of 3 months. It was found that both neat PLA and composites followed Fickian diffusion. Higher temperature generally increased the Diffusion coefficient, D of neat PLA and composites, as well as shortening the saturation time. Neat PLA had the lowest D value followed by AAL composites and then AUL composites. After hygrothermal ageing, tensile and flexural strength, Young’s and flexural modulus and KIc were found to decrease and impact strength was found to increase for both AUL and AAL composites. AUL composites had greater overall reduction in mechanical properties than that for AAL composites after hygrothermal ageing. Crystallinity contents of the hygrothermal aged composites support the results of the deterioration of mechanical properties upon exposure to hygrothermal ageing environment.

year: 2010

title: Hierarchical interface-based supervisory control using the conflict preorder

authors: Malik, Robi

subjects: discrete event systems

abstract: Hierarchical Interface-Based Supervisory Control decomposes a large discrete event system into subsystems linked to each other by interfaces, facilitating the design of complex systems and the re-use of components. By ensuring that each subsystem satisfies its interface consistency conditions locally, it can be ensured that the complete system is controllable and nonblocking. The interface consistency conditions proposed in this paper are based on the conflict preorder, providing increased flexibility over previous approaches. The framework requires only a small number of interface consistency conditions, and allows for the design of multi-level hierarchies that are provably controllable and nonblocking.

text: Hierarchical interface-based supervisory control using the conflict preorder Hierarchical Interface-Based Supervisory Control decomposes a large discrete event system into subsystems linked to each other by interfaces, facilitating the design of complex systems and the re-use of components. By ensuring that each subsystem satisfies its interface consistency conditions locally, it can be ensured that the complete system is controllable and nonblocking. The interface consistency conditions proposed in this paper are based on the conflict preorder, providing increased flexibility over previous approaches. The framework requires only a small number of interface consistency conditions, and allows for the design of multi-level hierarchies that are provably controllable and nonblocking.

year: 2012

title: Colouring in the White Spaces: Reclaiming Cultural Identity in Whitestream Schools

authors: Milne, Beverley Ann

subjects: Maori education

abstract: If we look at a child’s colouring book, before it has any colour added to it, we think of the page as blank.  It’s actually not blank, it’s white.  That white background is just “there” and we don’t think much about it.  Not only is the background uniformly white, the lines are already in place and they dictate where the colour is allowed to go.  When children are young, they don’t care where they put the colours, but as they get older they colour in more and more cautiously. They learn about the place of colour and the importance of staying within the pre-determined boundaries and expectations. 

This thesis argues that this is the setting for our mainstream, or what I have called, whitestream New Zealand schools — that white background is the norm.   When we talk about multiculturalism and diversity what we are really referring to is the colour of the children, or their difference from that white norm, and how they don’t fit perfectly inside our lines.  If the colour of the space doesn’t change schools are still in the business of assimilation, relegating non-white children to the margins, no matter how many school reform initiatives, new curricula, strategic plans, or mandated standards we implement.  What the schools in this study have tried to do is change the colour of the space – so that the space fits the children and they don’t have to constantly adjust to fit in.  

New Zealand’s education system has been largely silent on the topic of whiteness and the Eurocentric nature of our schooling policy and practice. However, when I talk to senior Māori and Pasifika ‘warrior-scholars” in Te Whānau o Tupuranga and Clover Park Middle School about “white spaces” they have encountered in their schooling experience they can identify them all too easily.  “White spaces,” they explain, are anything you accept as “normal” for Māori – when it’s really not,  any situation that prevents, or works against you “being Māori” or who you are, and that requires you to “be” someone else and leave your beliefs behind. White spaces are spaces that allow you to require less of yourself and that reinforce stereotypes and negative ideas about Māori.  Most telling of all was the comment from a Māori student that goes straight to the root of the problem, “White spaces are everywhere,” she said, “even in your head.”

This thesis describes the 25 year journey of two schools and their community’s determination to resist and reject alienating school environments in favour of a relevant culturally-located, bilingual learning model based in a secure cultural identity, stable positive relationships, and aroha (authentic caring and love).  While the research design is a case study, in terms of western, “white space” academic tradition, it is also a story in terms of kaupapa Māori and critical race methodology. More importantly, it is a counter-story that chronicles the efforts of these two schools to step outside education’s “white spaces” to create new space.  This counter-story is juxtaposed against pervasive, deficit-driven whitestream explanations of “achievement gaps” and the “long tail” of Māori and Pasifika “under-achievement” in New Zealand schools.  In the process of this research the focus shifted from how could Māori and Pasifika learners develop secure cultural identities in mainstream schools, to examining what barriers exist in schools that prevent this from happening already?  As these issues became clear the language of the thesis shifted accordingly; “developing” a cultural identity was reframed as a reclamation of educational sovereignty — the absolute right to “be Māori” or “be Pasifika” in school — and “mainstream” schooling became better understood as the “whitestream.” 

The study hopes to contribute to the journey other schools might take to identify and name their own white spaces, and to make learning equitable for indigenous and minoritised learners.

text: Colouring in the White Spaces: Reclaiming Cultural Identity in Whitestream Schools If we look at a child’s colouring book, before it has any colour added to it, we think of the page as blank.  It’s actually not blank, it’s white.  That white background is just “there” and we don’t think much about it.  Not only is the background uniformly white, the lines are already in place and they dictate where the colour is allowed to go.  When children are young, they don’t care where they put the colours, but as they get older they colour in more and more cautiously. They learn about the place of colour and the importance of staying within the pre-determined boundaries and expectations. 

This thesis argues that this is the setting for our mainstream, or what I have called, whitestream New Zealand schools — that white background is the norm.   When we talk about multiculturalism and diversity what we are really referring to is the colour of the children, or their difference from that white norm, and how they don’t fit perfectly inside our lines.  If the colour of the space doesn’t change schools are still in the business of assimilation, relegating non-white children to the margins, no matter how many school reform initiatives, new curricula, strategic plans, or mandated standards we implement.  What the schools in this study have tried to do is change the colour of the space – so that the space fits the children and they don’t have to constantly adjust to fit in.  

New Zealand’s education system has been largely silent on the topic of whiteness and the Eurocentric nature of our schooling policy and practice. However, when I talk to senior Māori and Pasifika ‘warrior-scholars” in Te Whānau o Tupuranga and Clover Park Middle School about “white spaces” they have encountered in their schooling experience they can identify them all too easily.  “White spaces,” they explain, are anything you accept as “normal” for Māori – when it’s really not,  any situation that prevents, or works against you “being Māori” or who you are, and that requires you to “be” someone else and leave your beliefs behind. White spaces are spaces that allow you to require less of yourself and that reinforce stereotypes and negative ideas about Māori.  Most telling of all was the comment from a Māori student that goes straight to the root of the problem, “White spaces are everywhere,” she said, “even in your head.”

This thesis describes the 25 year journey of two schools and their community’s determination to resist and reject alienating school environments in favour of a relevant culturally-located, bilingual learning model based in a secure cultural identity, stable positive relationships, and aroha (authentic caring and love).  While the research design is a case study, in terms of western, “white space” academic tradition, it is also a story in terms of kaupapa Māori and critical race methodology. More importantly, it is a counter-story that chronicles the efforts of these two schools to step outside education’s “white spaces” to create new space.  This counter-story is juxtaposed against pervasive, deficit-driven whitestream explanations of “achievement gaps” and the “long tail” of Māori and Pasifika “under-achievement” in New Zealand schools.  In the process of this research the focus shifted from how could Māori and Pasifika learners develop secure cultural identities in mainstream schools, to examining what barriers exist in schools that prevent this from happening already?  As these issues became clear the language of the thesis shifted accordingly; “developing” a cultural identity was reframed as a reclamation of educational sovereignty — the absolute right to “be Māori” or “be Pasifika” in school — and “mainstream” schooling became better understood as the “whitestream.” 

The study hopes to contribute to the journey other schools might take to identify and name their own white spaces, and to make learning equitable for indigenous and minoritised learners.

year: 2013