title: Manufacturing and characterization of sustainable hybrid composites using sisal and hemp fibres as reinforcement of poly (lactic acid) via injection moulding

authors: Pappu, Asokan

subjects: Science & Technology

abstract: Natural polymers based composites offers significant advantages over synthetic fibre reinforced petroleum matrix based composites with regard to biodegradability, biocompatibility, design flexibility and sustainability. This work reports for the first time manufacturing of hybrid fibre reinforced biodegradable composites using sisal and hemp fibre with polylactic acid employing melt processing and injection moulding techniques. Granulated sisal and hemp fibres were blended and hybrid composites were manufactured using aliphatic polyester made up of lactic acid (PLA) through extrusion and injection moulding and their performance was evaluated. Experimental results revealed that density, elongation at break and water absorption capacity of hybrid composites were 1.14 ± 0.07 g/cm³, 0.93 ± 0.35% and 1.06 ± 0.18% respectively. The achieved mean tensile strength (46.25 ± 6.75 MPa), Young’s modulus (6.1 ± 0.58 GPa) and specific tensile strength (38.86 ± 5.0) of hybrid fibre reinforced PLA composites were improved compared to neat PLA. The flexural strength (94.83 ± 11.21 MPa), flexural modulus (6.04 ± 0.55 GPA) and specific flexural strength (79.76 ± 8.80) of hybrid fibre composites also showed better performance than those of neat PLA. Incorporation of sisal and hemp fibre with polylactide remarkably increased the impact strength of composites. Overall, the hybrid composites demonstrated good performance suggesting that they have great potential for use as an environmentally friendly alternative material in automotive, packaging, electronics, interiors and agricultural applications.

text: Manufacturing and characterization of sustainable hybrid composites using sisal and hemp fibres as reinforcement of poly (lactic acid) via injection moulding Natural polymers based composites offers significant advantages over synthetic fibre reinforced petroleum matrix based composites with regard to biodegradability, biocompatibility, design flexibility and sustainability. This work reports for the first time manufacturing of hybrid fibre reinforced biodegradable composites using sisal and hemp fibre with polylactic acid employing melt processing and injection moulding techniques. Granulated sisal and hemp fibres were blended and hybrid composites were manufactured using aliphatic polyester made up of lactic acid (PLA) through extrusion and injection moulding and their performance was evaluated. Experimental results revealed that density, elongation at break and water absorption capacity of hybrid composites were 1.14 ± 0.07 g/cm³, 0.93 ± 0.35% and 1.06 ± 0.18% respectively. The achieved mean tensile strength (46.25 ± 6.75 MPa), Young’s modulus (6.1 ± 0.58 GPa) and specific tensile strength (38.86 ± 5.0) of hybrid fibre reinforced PLA composites were improved compared to neat PLA. The flexural strength (94.83 ± 11.21 MPa), flexural modulus (6.04 ± 0.55 GPA) and specific flexural strength (79.76 ± 8.80) of hybrid fibre composites also showed better performance than those of neat PLA. Incorporation of sisal and hemp fibre with polylactide remarkably increased the impact strength of composites. Overall, the hybrid composites demonstrated good performance suggesting that they have great potential for use as an environmentally friendly alternative material in automotive, packaging, electronics, interiors and agricultural applications.

year: 2019

title: An analysis of classroom verbal interaction, teacher and participant location, and group activities: A pilot study

authors: Codyre, Martin Allen

abstract: At a time when so much intellectual energy is being expended in discussions about educational "accountability" and the end product of the educational system, it seems appropriate to begin to focus empirically on the "input" of education in an attempt to enhance the "output". In its relatively short history, educational research in New Zealand has tended to look at the broader issues of education rather than at the specifics of classrooms. To date, very little data has been collected relating to the activities that occur in the typical New Zealand classrooms in different types of school at various levels.

text: An analysis of classroom verbal interaction, teacher and participant location, and group activities: A pilot study At a time when so much intellectual energy is being expended in discussions about educational "accountability" and the end product of the educational system, it seems appropriate to begin to focus empirically on the "input" of education in an attempt to enhance the "output". In its relatively short history, educational research in New Zealand has tended to look at the broader issues of education rather than at the specifics of classrooms. To date, very little data has been collected relating to the activities that occur in the typical New Zealand classrooms in different types of school at various levels.

year: 1973

title: Monitoring te mana o te wai: Intergrating an indigenous cultural health index with conventional biomonitoring tools for improved freshwater management

authors: Edgecombe, Shana Jade Te Iaa Tarere

subjects: Freshwater

abstract: Globally, there are universal efforts to quantify and address human impacts on ecosystems. In particular, changes in land use and river regulation have led to drastic declines in stream and river ecosystem health. These human impacts are driving the global freshwater biodiversity crisis and degrade ecosystem services provided by aquatic habitats. In Aotearoa New Zealand there is widespread concern about the state of our Nation’s freshwater ecosystems. Coupled with a renaissance in Māori culture, there has been a drive to develop indicators that help articulate cultural values, assess ecosystem health from a cultural perspective, and provide greater agency for Māori in environmental monitoring and management. In my thesis, I sought to integrate an established cultural monitoring framework with conventional biomonitoring tools for improved freshwater management. I hypothesized that using a suite of monitoring approaches would help detect the impacts of human land use on stream ecosystem health, and that cultural indicators would be consistent with conventional measures in diagnosing land use impacts. I also hypothesized that there could be discrepancies between cultural monitoring and conventional approaches, as each represent different perspectives and ways of knowing streams and rivers. 
To test my hypotheses, I selected ten stream sites across the catchment of the Kuratau River, a major tributary of Lake Taupō. Based on River Environment Classification land cover types, I used a balanced study design with five sites draining indigenous forest, and five sites draining pastoral land. I measured key stream physicochemical properties and collected water samples for determination of nutrient concentration and faecal coliform counts. I also characterised instream and riparian habitat. I collected benthic macroinvertebrate samples and sampled water for environmental DNA (eDNA) to assess different facets of biodiversity. I measured decomposition using the Cotton Strip Assay and quantified periphyton biomass using a portable fluorometer. In combination with these approaches, I also used a Cultural Health Index, an established cultural monitoring framework that assesses three components: customary significance, taonga species/mahinga kai (food gathering), and the Cultural Stream Health Measure (CSHM) to assess identified attributes for stream health.
I found that pastoral land uses lead to a decline in stream ecosystem health when compared to sites draining indigenous forest. Pastoral sites had higher specific conductivity and concentrations of total nitrogen and nitrate. Habitat variables changed, with increased sedimentation and more degraded riparian zones in pastoral streams. Decomposition rates as measured by the cotton strip assay increased in the pasture sites, which was likely a response to increased nutrient availability. There were shifts in macroinvertebrate composition, with key indicator taxa for Indigenous forest sites including pollution-sensitive mayflies and stoneflies. Total taxa, EPT (Ephemeroptera, Plecoptera, Trichoptera), and aquatic insect richness all significantly declined in pastoral sites. Increases in primary production were less pronounced, but did increase alongside abundances of grazing caddisflies and snails in the sites draining pastoral catchments. 
The Cultural Health Index indicated that sites in the Kuratau River catchment had customary and mahinga kai values. CSHM responded negatively to pastoral land uses, and the effect size it described was congruent with other responses. The CSHM was strongly correlated with an indicator of riparian habitat condition (the Riparian Condition Index) and had weak negative correlations with sedimentation and stream temperatures. The CSHM was not correlated with macroinvertebrate indices, which may have been because of the relatively few sites sampled, the narrow impact gradient in the Kuratau catchment, and the lack of temporal replication. However, cultural monitoring approaches should be seen to complement conventional environmental monitoring methods for assessing freshwater and not be expected to duplicate them. The strength of the Cultural Health Index approach comes from establishing Māori agency to assess the environment through a Te Ao Māori lens, and to support and foster inclusion for tangata whenua epistemologies in environmental monitoring and resource management. Future research should consider greater hapū involvement and further explore the mechanisms driving changes in stream health and biodiversity.

text: Monitoring te mana o te wai: Intergrating an indigenous cultural health index with conventional biomonitoring tools for improved freshwater management Globally, there are universal efforts to quantify and address human impacts on ecosystems. In particular, changes in land use and river regulation have led to drastic declines in stream and river ecosystem health. These human impacts are driving the global freshwater biodiversity crisis and degrade ecosystem services provided by aquatic habitats. In Aotearoa New Zealand there is widespread concern about the state of our Nation’s freshwater ecosystems. Coupled with a renaissance in Māori culture, there has been a drive to develop indicators that help articulate cultural values, assess ecosystem health from a cultural perspective, and provide greater agency for Māori in environmental monitoring and management. In my thesis, I sought to integrate an established cultural monitoring framework with conventional biomonitoring tools for improved freshwater management. I hypothesized that using a suite of monitoring approaches would help detect the impacts of human land use on stream ecosystem health, and that cultural indicators would be consistent with conventional measures in diagnosing land use impacts. I also hypothesized that there could be discrepancies between cultural monitoring and conventional approaches, as each represent different perspectives and ways of knowing streams and rivers. 
To test my hypotheses, I selected ten stream sites across the catchment of the Kuratau River, a major tributary of Lake Taupō. Based on River Environment Classification land cover types, I used a balanced study design with five sites draining indigenous forest, and five sites draining pastoral land. I measured key stream physicochemical properties and collected water samples for determination of nutrient concentration and faecal coliform counts. I also characterised instream and riparian habitat. I collected benthic macroinvertebrate samples and sampled water for environmental DNA (eDNA) to assess different facets of biodiversity. I measured decomposition using the Cotton Strip Assay and quantified periphyton biomass using a portable fluorometer. In combination with these approaches, I also used a Cultural Health Index, an established cultural monitoring framework that assesses three components: customary significance, taonga species/mahinga kai (food gathering), and the Cultural Stream Health Measure (CSHM) to assess identified attributes for stream health.
I found that pastoral land uses lead to a decline in stream ecosystem health when compared to sites draining indigenous forest. Pastoral sites had higher specific conductivity and concentrations of total nitrogen and nitrate. Habitat variables changed, with increased sedimentation and more degraded riparian zones in pastoral streams. Decomposition rates as measured by the cotton strip assay increased in the pasture sites, which was likely a response to increased nutrient availability. There were shifts in macroinvertebrate composition, with key indicator taxa for Indigenous forest sites including pollution-sensitive mayflies and stoneflies. Total taxa, EPT (Ephemeroptera, Plecoptera, Trichoptera), and aquatic insect richness all significantly declined in pastoral sites. Increases in primary production were less pronounced, but did increase alongside abundances of grazing caddisflies and snails in the sites draining pastoral catchments. 
The Cultural Health Index indicated that sites in the Kuratau River catchment had customary and mahinga kai values. CSHM responded negatively to pastoral land uses, and the effect size it described was congruent with other responses. The CSHM was strongly correlated with an indicator of riparian habitat condition (the Riparian Condition Index) and had weak negative correlations with sedimentation and stream temperatures. The CSHM was not correlated with macroinvertebrate indices, which may have been because of the relatively few sites sampled, the narrow impact gradient in the Kuratau catchment, and the lack of temporal replication. However, cultural monitoring approaches should be seen to complement conventional environmental monitoring methods for assessing freshwater and not be expected to duplicate them. The strength of the Cultural Health Index approach comes from establishing Māori agency to assess the environment through a Te Ao Māori lens, and to support and foster inclusion for tangata whenua epistemologies in environmental monitoring and resource management. Future research should consider greater hapū involvement and further explore the mechanisms driving changes in stream health and biodiversity.

year: 2024