title: Potential of cellulose microfibers for PHA and PLA biopolymers reinforcement.

authors: Mármol, Gonzalo

subjects: biopolymers

abstract: Cellulose nanocrystals (CNC) have attracted the attention of many engineering fields and offered excellent mechanical and physical properties as polymer reinforcement. However, their application in composite products with high material demand is complex due to the current production costs. This work explores the use of cellulose microfibers (MF) obtained by a straightforward water dispersion of kraft paper to reinforce polyhydroxyalkanoate (PHA) and polylactic acid (PLA) films. To assess the influence of this type of filler material on the properties of biopolymers, films were cast and reinforced at different scales, with both CNC and MF separately, to compare their effectiveness. Regarding mechanical properties, CNC has a better reinforcing effect on the tensile strength of PLA samples, though up to 20 wt.% of MF may also lead to stronger PLA films. Moreover, PHA films reinforced with MF are 23% stronger than neat PHA samples. This gain in strength is accompanied by an increment of the stiffness of the material. Additionally, the addition of MF leads to an increase in the crystallinity of PHA that can be controlled by heat treatment followed by quenching. This change in the crystallinity of PHA affects the hygroscopicity of PHA samples, allowing the modification of the water barrier properties according to the required features. The addition of MF to both types of polymers also increases the surface roughness of the films, which may contribute to obtaining better interlaminar bonding in multi-layer composite applications. Due to the partial lignin content in MF from kraft paper, samples reinforced with MF present a UV blocking effect. Therefore, MF from kraft paper may be explored as a way to introduce high fiber concentrations (up to 20 wt.%) from other sources of recycled paper into biocomposite manufacturing with economic and technical benefits.

text: Potential of cellulose microfibers for PHA and PLA biopolymers reinforcement. Cellulose nanocrystals (CNC) have attracted the attention of many engineering fields and offered excellent mechanical and physical properties as polymer reinforcement. However, their application in composite products with high material demand is complex due to the current production costs. This work explores the use of cellulose microfibers (MF) obtained by a straightforward water dispersion of kraft paper to reinforce polyhydroxyalkanoate (PHA) and polylactic acid (PLA) films. To assess the influence of this type of filler material on the properties of biopolymers, films were cast and reinforced at different scales, with both CNC and MF separately, to compare their effectiveness. Regarding mechanical properties, CNC has a better reinforcing effect on the tensile strength of PLA samples, though up to 20 wt.% of MF may also lead to stronger PLA films. Moreover, PHA films reinforced with MF are 23% stronger than neat PHA samples. This gain in strength is accompanied by an increment of the stiffness of the material. Additionally, the addition of MF leads to an increase in the crystallinity of PHA that can be controlled by heat treatment followed by quenching. This change in the crystallinity of PHA affects the hygroscopicity of PHA samples, allowing the modification of the water barrier properties according to the required features. The addition of MF to both types of polymers also increases the surface roughness of the films, which may contribute to obtaining better interlaminar bonding in multi-layer composite applications. Due to the partial lignin content in MF from kraft paper, samples reinforced with MF present a UV blocking effect. Therefore, MF from kraft paper may be explored as a way to introduce high fiber concentrations (up to 20 wt.%) from other sources of recycled paper into biocomposite manufacturing with economic and technical benefits.

year: 2020

title: How do Pasifika students reason about probability? Some findings from Fiji.

authors: Sharma, Sashi

subjects: Fijian-Indian

abstract: This paper reports on data from a large study which explored form five (14 to 16 years old) students' ideas in statistics. The study focused on descriptive statistics, graphical representations and probability. This paper discusses the ways in which students made sense of probability questions obtained from the individual interviews. The findings revealed that many of the students used strategies based on prior experiences (beliefs, cultural and school experiences) and intuitive strategies. From the analysis, I identified a four-category rubric that could be considered for describing how students construct meanings for statistics tasks. While the results of the study confirm a number of findings of other researchers, the findings go beyond those discussed in the literature. The use of beliefs and everyday and school experiences was considerably more common than that discussed in literature. The paper concludes by suggesting some implications for teachers and researchers.

text: How do Pasifika students reason about probability? Some findings from Fiji. This paper reports on data from a large study which explored form five (14 to 16 years old) students' ideas in statistics. The study focused on descriptive statistics, graphical representations and probability. This paper discusses the ways in which students made sense of probability questions obtained from the individual interviews. The findings revealed that many of the students used strategies based on prior experiences (beliefs, cultural and school experiences) and intuitive strategies. From the analysis, I identified a four-category rubric that could be considered for describing how students construct meanings for statistics tasks. While the results of the study confirm a number of findings of other researchers, the findings go beyond those discussed in the literature. The use of beliefs and everyday and school experiences was considerably more common than that discussed in literature. The paper concludes by suggesting some implications for teachers and researchers.

year: 2006

title: The Pene Haare manuscript and issues associated with the translation of historical texts written in indigenous languages

authors: Tipene, Jillian

subjects: Māori manuscripts

abstract: With particular reference to a request to translate into English a manuscript dated 1923 and written by the Māori author Ngakuru Pene Haare, we identify here a range of issues and problems associated with the translation of historical texts written in indigenous languages, suggesting ways in which they might be addressed. Among the problems identified in this case are the paucity of information that is publicly available about the author, the context in which he lived and worked and the events about which he wrote, the absence, or sporadic use in the manuscript of a range of conventions associated with contemporary writing, the occurrence of archaic and/or esoteric words and expressions, and the presence of symbolism that is deeply culturally-embedded. The primary conclusion is that the translation of manuscripts such as this must be ethically-grounded and fully research-embedded. It must therefore involve the mentorship of knowledgeable elders, be guided by procedures that are appropriate in terms of the culture out of which the source text emerged, accompanied by meticulous and wide-ranging research, and take full account of the wishes of the author of the manuscript where these have been stated, or can be inferred.

text: The Pene Haare manuscript and issues associated with the translation of historical texts written in indigenous languages With particular reference to a request to translate into English a manuscript dated 1923 and written by the Māori author Ngakuru Pene Haare, we identify here a range of issues and problems associated with the translation of historical texts written in indigenous languages, suggesting ways in which they might be addressed. Among the problems identified in this case are the paucity of information that is publicly available about the author, the context in which he lived and worked and the events about which he wrote, the absence, or sporadic use in the manuscript of a range of conventions associated with contemporary writing, the occurrence of archaic and/or esoteric words and expressions, and the presence of symbolism that is deeply culturally-embedded. The primary conclusion is that the translation of manuscripts such as this must be ethically-grounded and fully research-embedded. It must therefore involve the mentorship of knowledgeable elders, be guided by procedures that are appropriate in terms of the culture out of which the source text emerged, accompanied by meticulous and wide-ranging research, and take full account of the wishes of the author of the manuscript where these have been stated, or can be inferred.

year: 2009