title: A new method for producing polylactic acid biocomposites for 3D printing with improved tensile and thermo-mechanical performance using grafted nanofibrillated cellulose

authors: Gauss, Christian

abstract: In this work, a new methodology was developed to disperse nanofibrillated cellulose (CNF) in polylactic acid (PLA) composites for 3D printing. The nanofibres were modified by grafting PLA onto their surface through in-situ polymerisation of L-lactide. This modification changed subsequent fibre/PLA interaction and enabled the production of reinforced microparticles by a Pickering emulsion approach. We demonstrated that filaments produced with these microparticles containing up to 20 wt% of grafted CNF (g-CNF) can be processed and printed using the same printing parameters as used for neat PLA. The printed samples presented superior tensile properties, enhanced thermo-mechanical stability, and were dimensionally stable upon PLA crystallisation when g-CNF content is above 10 wt%. When heat-treated after printing the composite with 10 wt% of g-CNF achieved an ultimate tensile strength and Young's modulus of 72 MPa and 5.4 GPa, respectively. Post-printing annealing also increased thermo-mechanical stability of the composites achieving a storage modulus at 80 °C up to 850 times the storage modulus of neat PLA at the same temperature.

text: A new method for producing polylactic acid biocomposites for 3D printing with improved tensile and thermo-mechanical performance using grafted nanofibrillated cellulose In this work, a new methodology was developed to disperse nanofibrillated cellulose (CNF) in polylactic acid (PLA) composites for 3D printing. The nanofibres were modified by grafting PLA onto their surface through in-situ polymerisation of L-lactide. This modification changed subsequent fibre/PLA interaction and enabled the production of reinforced microparticles by a Pickering emulsion approach. We demonstrated that filaments produced with these microparticles containing up to 20 wt% of grafted CNF (g-CNF) can be processed and printed using the same printing parameters as used for neat PLA. The printed samples presented superior tensile properties, enhanced thermo-mechanical stability, and were dimensionally stable upon PLA crystallisation when g-CNF content is above 10 wt%. When heat-treated after printing the composite with 10 wt% of g-CNF achieved an ultimate tensile strength and Young's modulus of 72 MPa and 5.4 GPa, respectively. Post-printing annealing also increased thermo-mechanical stability of the composites achieving a storage modulus at 80 °C up to 850 times the storage modulus of neat PLA at the same temperature.

year: 2023-01-05

title: "Be feared, or live in fear": A descriptive model of institutional gang violence

authors: Brennan-Tupara, Nicola Dawn

subjects: Gang

abstract: Prison violence is a significant concern both in New Zealand and across the globe. While past theories and empirical research have highlighted several risk factors implicated in prison violence, we continue to have a limited understanding of what happens, and why it happens, during a prison violence event (PVE). Furthermore, we have even less of an understanding about the involvement of gangs in prison violence despite research suggesting that gang members are over-represented when it comes to involvement in such incidents. Previous research on gang violence in prison also focuses heavily on prisons in the United States of America which have different cultural, social, and judicial dimensions and may not generalise to the New Zealand prison population. This research project aimed to fill some of these gaps by taking an exploratory approach to induce new ideas following interviews with gang members who have first-hand experience with perpetrating prison violence. We used Grounded Theory to collect and analyse event descriptions to build a descriptive model of institutional gang violence which describes the distal and proximal features of the PVE process. The resulting model contributes to a better understanding of the function of PVEs involving gang members and the extent to which these events differ when carried out for or on behalf of the gang. It also highlights the role of past trauma and the prison ecology in the perpetuation of these events.

text: "Be feared, or live in fear": A descriptive model of institutional gang violence Prison violence is a significant concern both in New Zealand and across the globe. While past theories and empirical research have highlighted several risk factors implicated in prison violence, we continue to have a limited understanding of what happens, and why it happens, during a prison violence event (PVE). Furthermore, we have even less of an understanding about the involvement of gangs in prison violence despite research suggesting that gang members are over-represented when it comes to involvement in such incidents. Previous research on gang violence in prison also focuses heavily on prisons in the United States of America which have different cultural, social, and judicial dimensions and may not generalise to the New Zealand prison population. This research project aimed to fill some of these gaps by taking an exploratory approach to induce new ideas following interviews with gang members who have first-hand experience with perpetrating prison violence. We used Grounded Theory to collect and analyse event descriptions to build a descriptive model of institutional gang violence which describes the distal and proximal features of the PVE process. The resulting model contributes to a better understanding of the function of PVEs involving gang members and the extent to which these events differ when carried out for or on behalf of the gang. It also highlights the role of past trauma and the prison ecology in the perpetuation of these events.

year: 2023

title: Piahana Hou: a Ngati Rahiri rangatira

authors: Hart, Philip

abstract: Piahana Hou, as the half-brother of Karauna Hou, had an illustrious ancestry, but to Pakeha he was known as, briefly, the skipper of a river steamer and, for most of his life, as a labourer. His interests in several blocks of land enabled him to obtain money through selling some of his holdings, but he never became prosperous. He had minimal involvement in mining at Te Aroha.
Piahana came to prominence not as a rangatira but as a drunk, who was even involved in a bar fight at Te Aroha. Despite this weakness, his high status meant that hundreds attended his splendid tangi. Unlike some other rangatira, he did not use his status to play an important role in either Maori or Pakeha society.

text: Piahana Hou: a Ngati Rahiri rangatira Piahana Hou, as the half-brother of Karauna Hou, had an illustrious ancestry, but to Pakeha he was known as, briefly, the skipper of a river steamer and, for most of his life, as a labourer. His interests in several blocks of land enabled him to obtain money through selling some of his holdings, but he never became prosperous. He had minimal involvement in mining at Te Aroha.
Piahana came to prominence not as a rangatira but as a drunk, who was even involved in a bar fight at Te Aroha. Despite this weakness, his high status meant that hundreds attended his splendid tangi. Unlike some other rangatira, he did not use his status to play an important role in either Maori or Pakeha society.

year: 2016