title: Development of an online metric rugby analysis tool

authors: Smith, Tiaki Brett

abstract: Optimising conditioning of team sport players such as rugby union requires effective assessment, planning, implementation and monitoring. While there are few problems with the first three of these stages, the common Super 15 rugby strategy of conditioning games makes effective monitoring difficult. That is, instead of conditioning drills involving a series of defined movements over set distances, the players are involved in games to develop both conditioning and specific technical and/or tactical skills. The result is often highly individualised movement patterns, which has made monitoring distance and speed throughout the session problematic. The recent invention of small rugged portable global positioning system (GPS) units that integrate triaxial accelerometers and heart rate monitors, should provide a useful monitoring tool. In order for these units to be useful monitoring tools, the relevant metrics must be determined and their accuracy defined. The metrics must also be reported in a manner that is meaningful for trainers, coaches and support staff. This presentation will focus on the work of the authors with Statsports ltd (Dundalk, Ireland) who have developed GPS units for rugby union. This work involves identifying a set of metrics for monitoring the Chiefs super 15 rugby team during training and games. An online analysis package created by the authors will be demonstrated and opportunities for collaboration on further developments will be discussed.

text: Development of an online metric rugby analysis tool Optimising conditioning of team sport players such as rugby union requires effective assessment, planning, implementation and monitoring. While there are few problems with the first three of these stages, the common Super 15 rugby strategy of conditioning games makes effective monitoring difficult. That is, instead of conditioning drills involving a series of defined movements over set distances, the players are involved in games to develop both conditioning and specific technical and/or tactical skills. The result is often highly individualised movement patterns, which has made monitoring distance and speed throughout the session problematic. The recent invention of small rugged portable global positioning system (GPS) units that integrate triaxial accelerometers and heart rate monitors, should provide a useful monitoring tool. In order for these units to be useful monitoring tools, the relevant metrics must be determined and their accuracy defined. The metrics must also be reported in a manner that is meaningful for trainers, coaches and support staff. This presentation will focus on the work of the authors with Statsports ltd (Dundalk, Ireland) who have developed GPS units for rugby union. This work involves identifying a set of metrics for monitoring the Chiefs super 15 rugby team during training and games. An online analysis package created by the authors will be demonstrated and opportunities for collaboration on further developments will be discussed.

year: 2013

title: Bio-composites materials from engineered natural fibres for structural applications

authors: Mohd Ghazali, Aruan Efendy

subjects: Aligned discontinuous natural fibre composites

abstract: The large environmental footprint caused by conventional synthetic fibre reinforced petrochemical-derived polymer composites along with potential improvement in mechanical properties for natural fibre reinforced bio-derived polymer composites, have long been a motivation for further research and innovation in natural fibre composites. Harakeke and hemp fibres, amongst other natural fibres, possess respectable mechanical properties along with other advantages such as low cost, low production energy requirements and abundant availability. Polylactic acid (PLA), a sustainable alternative to petrochemical-derived polymers, is produced on a mass scale from 100% renewable resources and can be degraded at end of life by simple hydrolysis under the appropriate conditions. It has high stiffness, strength, thermal and UV stability, but is low in toughness. Limited applications of natural fibre reinforced PLA composites so far is mainly due to low mechanical properties of discontinuous fibre composites made using injection moulding or compression moulding using randomly oriented fibre mats attributed to poor fibre orientation and fibre-matrix incompatibility. Presented in this study are experimental investigations of the properties of PLA reinforced aligned discontinuous harakeke and hemp fibre mats produced using a dynamic sheet former (DSF) to provide improved performance of discontinuous fibre composites.

Harakeke and hemp fibres were treated using either a solution of 5 wt% or 10 wt% NaOH or combination of 5 wt% NaOH with 2 wt% Na2SO3 at elevated temperatures in a small pressure vessel. Treated fibres were assessed using single fibre tensile testing, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). It was found that 5 wt% NaOH/2 wt% Na2SO3 and 5 wt% NaOH effectively removed non-cellulosic materials from harakeke and hemp fibre surfaces, respectively, giving good fibre separation without greatly reducing the tensile strength of the fibres. It was also found that these treatments lead to a higher crystallinity index and improved thermal stability of fibres.

Fibre alignment in fibre mats produced using a DSF was observed using light microscopy. Visual observation supported that the fibre alignment had occurred. Fibre orientation factors (Kɵ) determined for harakeke and hemp composites using the Bowyer-Bader model were found higher compared to Kɵ values obtained for other natural composites prepared using injection and compression moulding. Improved fibre orientation resulted in improved reinforcement giving large increases for tensile strengths up to approximately 90 and 60% for harakeke and hemp composites reinforced with inclusion of 30 and 25 wt% fibre respectively. 

The effect of silane and peroxide as additional fibre treatments and MA-g-PLA as a coupling agent was evaluated by scanning electron microscopy (SEM), composite swelling analysis, tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Scanning electron micrographs of fractured composite surfaces revealed that the gaps between fibres and matrix for composites with fibres treated using silane and peroxide and composites coupled with MA-g-PLA were smaller compared to the surfaces for composites with fibres treated using just alkali. Improved interfacial strength was also supported by lower swelling indices, lower peaks on tan δ and higher residual composites weights, compared to those values obtained for composites with fibres treated using just alkali, which was found to lead to higher composite tensile strengths.

Harakeke and hemp fibre composites were plasticised using hyper-branched polymer (HBP) and assessed using SEM, tensile and impact testing. SEM micrographs for plasticised composites revealed longer pultruding fibres than un-plasticised composites, with gaps between the fibre and matrix appearing to be slightly larger, indicating a weaker interface between fibres and matrix compared to those composites without plasticiser. Improved composite ductility and impact strength were demonstrated for plasticised composites without dramatic reduction of composite tensile strength.

text: Bio-composites materials from engineered natural fibres for structural applications The large environmental footprint caused by conventional synthetic fibre reinforced petrochemical-derived polymer composites along with potential improvement in mechanical properties for natural fibre reinforced bio-derived polymer composites, have long been a motivation for further research and innovation in natural fibre composites. Harakeke and hemp fibres, amongst other natural fibres, possess respectable mechanical properties along with other advantages such as low cost, low production energy requirements and abundant availability. Polylactic acid (PLA), a sustainable alternative to petrochemical-derived polymers, is produced on a mass scale from 100% renewable resources and can be degraded at end of life by simple hydrolysis under the appropriate conditions. It has high stiffness, strength, thermal and UV stability, but is low in toughness. Limited applications of natural fibre reinforced PLA composites so far is mainly due to low mechanical properties of discontinuous fibre composites made using injection moulding or compression moulding using randomly oriented fibre mats attributed to poor fibre orientation and fibre-matrix incompatibility. Presented in this study are experimental investigations of the properties of PLA reinforced aligned discontinuous harakeke and hemp fibre mats produced using a dynamic sheet former (DSF) to provide improved performance of discontinuous fibre composites.

Harakeke and hemp fibres were treated using either a solution of 5 wt% or 10 wt% NaOH or combination of 5 wt% NaOH with 2 wt% Na2SO3 at elevated temperatures in a small pressure vessel. Treated fibres were assessed using single fibre tensile testing, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). It was found that 5 wt% NaOH/2 wt% Na2SO3 and 5 wt% NaOH effectively removed non-cellulosic materials from harakeke and hemp fibre surfaces, respectively, giving good fibre separation without greatly reducing the tensile strength of the fibres. It was also found that these treatments lead to a higher crystallinity index and improved thermal stability of fibres.

Fibre alignment in fibre mats produced using a DSF was observed using light microscopy. Visual observation supported that the fibre alignment had occurred. Fibre orientation factors (Kɵ) determined for harakeke and hemp composites using the Bowyer-Bader model were found higher compared to Kɵ values obtained for other natural composites prepared using injection and compression moulding. Improved fibre orientation resulted in improved reinforcement giving large increases for tensile strengths up to approximately 90 and 60% for harakeke and hemp composites reinforced with inclusion of 30 and 25 wt% fibre respectively. 

The effect of silane and peroxide as additional fibre treatments and MA-g-PLA as a coupling agent was evaluated by scanning electron microscopy (SEM), composite swelling analysis, tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Scanning electron micrographs of fractured composite surfaces revealed that the gaps between fibres and matrix for composites with fibres treated using silane and peroxide and composites coupled with MA-g-PLA were smaller compared to the surfaces for composites with fibres treated using just alkali. Improved interfacial strength was also supported by lower swelling indices, lower peaks on tan δ and higher residual composites weights, compared to those values obtained for composites with fibres treated using just alkali, which was found to lead to higher composite tensile strengths.

Harakeke and hemp fibre composites were plasticised using hyper-branched polymer (HBP) and assessed using SEM, tensile and impact testing. SEM micrographs for plasticised composites revealed longer pultruding fibres than un-plasticised composites, with gaps between the fibre and matrix appearing to be slightly larger, indicating a weaker interface between fibres and matrix compared to those composites without plasticiser. Improved composite ductility and impact strength were demonstrated for plasticised composites without dramatic reduction of composite tensile strength.

year: 2016

title: Unpacking media narratives: Racism and problematic reasonings

authors: Tan, Kyle K. H.

abstract: In this research brief, we present summaries of four case studies of racism in mainstream and social media in Aotearoa. Through a series of carefully selected datasets sourced from TV episodes (Police TEN 7), print media such as news articles (including Northland checkpoints), and tweets (Three Waters reform), we outline how Māori are represented across these mediums. With an expert in language modelling on our team, we analysed large datasets that give us sufficient statistical power to infer specific Māori discourses on respective platforms. Further, we examined key themes that characterise how Māori are represented in the media and signal the scale of anti-Māori attacks. For instance, we found that the predominant discussion on Three Waters reform on Twitter focused on ‘conflict’ (distrust towards government; 33%) and ‘capability’ (questioning the credibility of the reform; 23%) rather than its core intention of promoting water ‘safety’ (7%). The modelling analysis was supplemented by in-depth qualitative analysis that integrates anti-Māori themes (Moewaka-Barnes et al., 2012) and problematic reasoning tactics (Sturgill, 2021) to elucidate how false, deficit-based rhetoric about Māori is deployed to fuel racism and disinformation. In summary, our findings reinforce Kupu Taea’s call for new media sectors to integrate Te Tiriti o Waitangi into their practices to safeguard Māori and other minoritised groups who are likely to be at the fore of racist attacks.

text: Unpacking media narratives: Racism and problematic reasonings In this research brief, we present summaries of four case studies of racism in mainstream and social media in Aotearoa. Through a series of carefully selected datasets sourced from TV episodes (Police TEN 7), print media such as news articles (including Northland checkpoints), and tweets (Three Waters reform), we outline how Māori are represented across these mediums. With an expert in language modelling on our team, we analysed large datasets that give us sufficient statistical power to infer specific Māori discourses on respective platforms. Further, we examined key themes that characterise how Māori are represented in the media and signal the scale of anti-Māori attacks. For instance, we found that the predominant discussion on Three Waters reform on Twitter focused on ‘conflict’ (distrust towards government; 33%) and ‘capability’ (questioning the credibility of the reform; 23%) rather than its core intention of promoting water ‘safety’ (7%). The modelling analysis was supplemented by in-depth qualitative analysis that integrates anti-Māori themes (Moewaka-Barnes et al., 2012) and problematic reasoning tactics (Sturgill, 2021) to elucidate how false, deficit-based rhetoric about Māori is deployed to fuel racism and disinformation. In summary, our findings reinforce Kupu Taea’s call for new media sectors to integrate Te Tiriti o Waitangi into their practices to safeguard Māori and other minoritised groups who are likely to be at the fore of racist attacks.

year: 2025