title: Comparison of strength and Young modulus of aligned discontinuous fibre PLA composites obtained experimentally and from theoretical prediction models

authors: Efendy, M.G. Aruan

subjects: Science & Technology

abstract: The present paper describes work carried out to compare the strength performance of PLA reinforced aligned discontinuous harakeke and hemp fibre mat composites evaluated experimentally and using various simple elastic mathematical prediction models. Fibre mats were produced by means of Dynamic Sheet Former (DSF), and stacked alternately with PLA sheets to produce composites with up to 40 wt% fibre content. The fibre content was increased from 5 wt% to 40 wt% using 5 wt% interval. In this work, both harakeke and hemp composites were manufactured using hot-press. It was found that, better agreement to the experiment was obtained for Young’s modulus compared to those composite strengths. The Modified Rule of Mixtures is found to give accuracy within 41% for strength, while the Cox model showing the best agreement (<10%) for Young’s modulus for fibre contents up to 25 wt%. Better agreement obtained for Young’s modulus is believed to due to less mechanism involved at where Young’s modulus is measured.

text: Comparison of strength and Young modulus of aligned discontinuous fibre PLA composites obtained experimentally and from theoretical prediction models The present paper describes work carried out to compare the strength performance of PLA reinforced aligned discontinuous harakeke and hemp fibre mat composites evaluated experimentally and using various simple elastic mathematical prediction models. Fibre mats were produced by means of Dynamic Sheet Former (DSF), and stacked alternately with PLA sheets to produce composites with up to 40 wt% fibre content. The fibre content was increased from 5 wt% to 40 wt% using 5 wt% interval. In this work, both harakeke and hemp composites were manufactured using hot-press. It was found that, better agreement to the experiment was obtained for Young’s modulus compared to those composite strengths. The Modified Rule of Mixtures is found to give accuracy within 41% for strength, while the Cox model showing the best agreement (<10%) for Young’s modulus for fibre contents up to 25 wt%. Better agreement obtained for Young’s modulus is believed to due to less mechanism involved at where Young’s modulus is measured.

year: 2019

title: Mechanism for grain refinement of magnesium alloys by superheating

authors: Cao, Peng

subjects: Magnesium alloys

abstract: The mechanisms for grain refinement of magnesium alloys by superheating have remained ambiguous since 1931. A model has been proposed on the basis of the recent understanding of the grain refinement of both high purity and commercial purity Mg–Al alloys. The model explains most of the experimental observations about superheating. Analysis of the grain size data obtained from different Mg–Al alloys as a function of the growth restriction factor with and without superheating provides good support to the model.

text: Mechanism for grain refinement of magnesium alloys by superheating The mechanisms for grain refinement of magnesium alloys by superheating have remained ambiguous since 1931. A model has been proposed on the basis of the recent understanding of the grain refinement of both high purity and commercial purity Mg–Al alloys. The model explains most of the experimental observations about superheating. Analysis of the grain size data obtained from different Mg–Al alloys as a function of the growth restriction factor with and without superheating provides good support to the model.

year: 2007-04

title: Editorial for “Unmasking Racism and Oppression in Psychology” – Part II

authors: Tan, Kyle K. H.

abstract: Since publishing the first part of the “Unmasking Racism and Oppression in Psychology” special issue in March 2025, we have received immense aroha and gratitude from colleagues and students eager to learn about the perspectives of Indigenous and minoritised groups in psychology and how they can support the development of an anti-racist discipline. Rather than seeking to prove the existence of racism in the field (Crossing et al., 2024), this issue centres on validating our authors’ experiences of navigating oppression, challenging Eurocentric psychology, resisting assimilation, and remaining grounded in Indigenous ontologies and epistemologies while staying accountable to their communities. Racism in psychology has been called out by many colleagues in Aotearoa (to name a few; Levy & Waitoki, 2016; Love, 2008; Pomare et al., 2021), and this issue responds to their concerns by amplifying solutions for change in the teaching, practice, and research of psychology.

text: Editorial for “Unmasking Racism and Oppression in Psychology” – Part II Since publishing the first part of the “Unmasking Racism and Oppression in Psychology” special issue in March 2025, we have received immense aroha and gratitude from colleagues and students eager to learn about the perspectives of Indigenous and minoritised groups in psychology and how they can support the development of an anti-racist discipline. Rather than seeking to prove the existence of racism in the field (Crossing et al., 2024), this issue centres on validating our authors’ experiences of navigating oppression, challenging Eurocentric psychology, resisting assimilation, and remaining grounded in Indigenous ontologies and epistemologies while staying accountable to their communities. Racism in psychology has been called out by many colleagues in Aotearoa (to name a few; Levy & Waitoki, 2016; Love, 2008; Pomare et al., 2021), and this issue responds to their concerns by amplifying solutions for change in the teaching, practice, and research of psychology.

year: 2025