title: Polylactide composites reinforced with pre-impregnated natural fibre and continuous cellulose yarns for 3D printing applications

authors: Priya Muthe, Lakshmi

subjects: additive manufacturing

abstract: Achieving high-performance 3D printing composite filaments requires addressing challenges related to fibre wetting and uniform fibre/polymer distribution. This study evaluates the effectiveness of solution (solvent-based) and emulsion (water-based) impregnation techniques to enhance fibre wetting in bleached flax yarns by polylactide (PLA). For the first time, continuous viscose yarn composites were also produced using both impregnation techniques. All the composites were carefully characterised throughout each stage of production. Initially, single yarns were impregnated and consolidated to optimise formulations and processing parameters. Solution impregnation resulted in the highest tensile strength (356 MPa) for PLA/bleached flax filaments, while emulsion impregnation yielded the highest tensile strength for PLA/viscose filaments (255 MPa) due to better fibre wetting and fibre distribution. Impregnated single yarns were then combined, with additional polymer added to produce filaments compatible with standard material extrusion 3D printers. Despite a reduction in the mechanical performance of the 3D-printed composites due to additional polymer impregnation, relatively high tensile and bending strengths were achieved, and the Charpy impact strength (&gt;127 kJ/m2) for the viscose-based composite exceeded the reported values for bio-derived fibre reinforced composites. The robust mechanical performance of these filaments offers new opportunities for the large-scale additive manufacturing of structural components from bio-derived and renewable resources.

text: Polylactide composites reinforced with pre-impregnated natural fibre and continuous cellulose yarns for 3D printing applications Achieving high-performance 3D printing composite filaments requires addressing challenges related to fibre wetting and uniform fibre/polymer distribution. This study evaluates the effectiveness of solution (solvent-based) and emulsion (water-based) impregnation techniques to enhance fibre wetting in bleached flax yarns by polylactide (PLA). For the first time, continuous viscose yarn composites were also produced using both impregnation techniques. All the composites were carefully characterised throughout each stage of production. Initially, single yarns were impregnated and consolidated to optimise formulations and processing parameters. Solution impregnation resulted in the highest tensile strength (356 MPa) for PLA/bleached flax filaments, while emulsion impregnation yielded the highest tensile strength for PLA/viscose filaments (255 MPa) due to better fibre wetting and fibre distribution. Impregnated single yarns were then combined, with additional polymer added to produce filaments compatible with standard material extrusion 3D printers. Despite a reduction in the mechanical performance of the 3D-printed composites due to additional polymer impregnation, relatively high tensile and bending strengths were achieved, and the Charpy impact strength (&gt;127 kJ/m2) for the viscose-based composite exceeded the reported values for bio-derived fibre reinforced composites. The robust mechanical performance of these filaments offers new opportunities for the large-scale additive manufacturing of structural components from bio-derived and renewable resources.

year: 2024

title: Does virtue ethics allow us to make better judgments of the actions of others?

authors: van Zyl, Liezl

subjects: Virtue ethics

abstract: Virtue ethics encourages us to judge the actions of others, not merely as right or wrong, but as virtuous (kind, courageous, just, compassionate, etc.) or vicious (cruel, cowardly, unjust, selfish, etc.). In doing so, however, we risk acting viciously ourselves. That is, our judgments of others can be unfair, unkind, insensitive, uncharitable, or hypocritical, even while being accurate. I argue that in order to make good judgments of the actions of others we should turn to virtue ethics for action guidance. That is, our primary aim should not be to make accurate judgments but to act virtuously when judging others.

text: Does virtue ethics allow us to make better judgments of the actions of others? Virtue ethics encourages us to judge the actions of others, not merely as right or wrong, but as virtuous (kind, courageous, just, compassionate, etc.) or vicious (cruel, cowardly, unjust, selfish, etc.). In doing so, however, we risk acting viciously ourselves. That is, our judgments of others can be unfair, unkind, insensitive, uncharitable, or hypocritical, even while being accurate. I argue that in order to make good judgments of the actions of others we should turn to virtue ethics for action guidance. That is, our primary aim should not be to make accurate judgments but to act virtuously when judging others.

year: 2019

title: Aihe Pepene

authors: Hart, Philip

abstract: Sharing the same illustrious whakapapa as his brother Reha Aperahama, Aihe Pepene was prominent when living in the Thames district before settling at Te Aroha in 1878. When speculators tried to acquire the Thames foreshore from Pepene and others in 1870, he became involved in the subsequent legal actions over unpaid promissory notes. Later he would acquire interests in many blocks of land, and received a steady income by leasing or selling these plus his share in the goldfields revenue. When the Aroha Block was considered by the land court for the last time, in 1878, he conducted the case for Ngati Rahiri.
He invested in four Hauraki goldfields, and was briefly an owner and skipper of two small river steamers, an unsuccessful endeavour that resulted in his being forced to sell more land to meet his debts. Once his 1880 and 1881 financial difficulties were resolved, no more such problems recurred. 
A leading rangatira in Hauraki generally as well as at Te Aroha, he would be elected to a Maori Committee that was soon revealed to have no significance. Closely involved with Pakeha, he assisted settlement, and his loyalty to the Crown was illustrated by his becoming an officer in the Thames Native Volunteer Corps. A member of the Church of England for many years, like many Maori he became a Mormon, a faith perhaps more appropriate to his private life, for he had more than one wife, notoriously eloping with the wife of a more senior rangatira despite already being married.

text: Aihe Pepene Sharing the same illustrious whakapapa as his brother Reha Aperahama, Aihe Pepene was prominent when living in the Thames district before settling at Te Aroha in 1878. When speculators tried to acquire the Thames foreshore from Pepene and others in 1870, he became involved in the subsequent legal actions over unpaid promissory notes. Later he would acquire interests in many blocks of land, and received a steady income by leasing or selling these plus his share in the goldfields revenue. When the Aroha Block was considered by the land court for the last time, in 1878, he conducted the case for Ngati Rahiri.
He invested in four Hauraki goldfields, and was briefly an owner and skipper of two small river steamers, an unsuccessful endeavour that resulted in his being forced to sell more land to meet his debts. Once his 1880 and 1881 financial difficulties were resolved, no more such problems recurred. 
A leading rangatira in Hauraki generally as well as at Te Aroha, he would be elected to a Maori Committee that was soon revealed to have no significance. Closely involved with Pakeha, he assisted settlement, and his loyalty to the Crown was illustrated by his becoming an officer in the Thames Native Volunteer Corps. A member of the Church of England for many years, like many Maori he became a Mormon, a faith perhaps more appropriate to his private life, for he had more than one wife, notoriously eloping with the wife of a more senior rangatira despite already being married.

year: 2016