Paul Memmott

Easily deconstructed, high aspect ratio cellulose nanofibres from Triodia pungens; an abundant grass of Australia's arid zone

The production of high aspect ratio cellulose nanofibres without resorting to very harsh mechanical and/or chemical processing steps remains a challenge that hinders progress in the fast-moving nanocellulose field. In response to this challenge, herein we report the preparation of high aspect ratio (>500) and small diameter (<8 nm) cellulose nanofibrils through the deconstruction of Australian native ‘spinifex’ grass (Triodia pungens) by applying very mild pulping conditions combined with only one pass of high pressure homogenization. Spinifex grass has an unusually high hemicellulose content, which facilitates this easy fibrillation process. Tensile measurements of the nanopaper produced by vacuum filtration indicated a high toughness of about 12 MJ m−3, a tensile strength of 82 MPa and a high elongation at break of 18%. The transverse elastic modulus of single nanofibrils analysed by AM-FM is in the range of 19–24 GPa. Under these mild processing conditions, Triodia pungens nanofibrils retained their crystallinity.

Indigenous and modern biomaterials derived from Triodia ('spinifex') grasslands in Australia.

Plant-derived fibres and resins can provide biomaterials with environmental, health and financial benefits. Australian arid zone grasses have not been explored as sources of modern biomaterials including building materials. Triodia grasslands are a dominant vegetation type in the arid and semiarid regions of Australia covering a third of the continent. Of the 69 identified Triodia species, 26 produce resin from specialised cells in the outer leaf epidermis. In Aboriginal culture, Triodia biomass and resin were valued for their usefulness in cladding shelters and as a hafting agent. Since European settlement, Triodia grasslands have been used for cattle grazing and burning is a common occurrence to improve pasture value and prevent large-scale fires. Although Triodia grasslands are relatively stable to fires, more frequent and large-scale fires impact on other fire sensitive woody and herbaceous species associated with Triodia and invasion of exotic weeds resulting in localised changes in vegetation structure and composition. The extent and change occurring in Triodia grasslands as a result of altered land-use practices, fire regimes, and changing climate warrant careful consideration of their future management. Localised harvesting of Triodia grasslands could have environmental benefits and provide much needed biomaterials for desert living. Research is underway to evaluate the material properties of Triodia biomass and resin in the context of Indigenous and western scientific knowledge. Here, we review uses of Triodia and highlight research needs if sustainable harvesting is to be considered.

An Aboriginal mother tells of the old and the new

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Preparation and characterization of spinifex resin based bio-polyurethane/thermoplastic polyurethane blends

Research interest is growing in the potential to strategically mix selected polymers to modify properties and reduce the cost of resultant blends. Renewable resource-derived spinifex resin-based polyurethane (RPU) can be considered a potential bio-alternative to conventional petroleum-based polymers. However, its inherent weak mechanical properties severely limit its range of applications. This study aimed to prepare a useful novel polymer by solution blending of polyurethane prepared from spinifex resin (endemic to Australia) and commercially available thermoplastic polyurethane (TPU). Properties of the prepared polymer blends were characterized using various techniques.

On Regional and Cultural Approaches to Australian Indigenous Violence

Abstract Based on a national analysis of Indigenous family violence, the 2001 monograph on ‘Violence in Indigenous Communities’ by the author and his colleagues for the Australian Attorney-Generals Department called for government agencies to ‘take a regional approach to supporting and co-ordinating local community initiatives’ together with ‘partnerships between Indigenous program personnel and mainstream services...’ (Memmott et al., 2001, p. 4). This current article reports on regional aspects of two subsequent pieces of research by the author, one in the Barkly Region of central-east Northern Territory for Anyinginyi Health Aboriginal Corporation (2007) and the other in the Torres Strait for the Queensland Department of Communities (2008). The research findings from both of these studies develop the case for government policy to accommodate regional approaches to Indigenous family violence due to combinations of geographic and culturally specific causal factors. The importance of nurturing social and cultural capital in Indigenous communities to strengthen social values, leadership and cohesion in addressing Indigenous violence will be emphasised. Some comment will be made on the role of underlying factors (‘deep historical circumstances’) in contributing to violence, in conjunction with precipitating causes and situational factors, the former being somewhat downplayed in policy debate over the period of the Howard government.

Indigenous Home Ownership and Community Title Land: A Preliminary Household Survey

Home ownership is currently not an option for Indigenous people living outside of urban centres. This article presents the results of a household survey conducted in four community settlements in Queensland revealing diverse understandings, aspirations and concerns for Indigenous home ownership. Discussion concludes that the development of a home ownership scheme will require rigorous policy analysis and innovative economic and cultural solutions.

Late Holocene Changes in Shellfishing Behaviors From the Gulf of Carpentaria, Northern Australia

ABSTRACT Dramatic changes in shellfishing behaviors occur across northern Australia during the late Holocene, marked most conspicuously by the cessation of large shell mound construction in some areas, and the reorganization of shellfishing behaviors towards more intensive production in the last 1,000 years. Excavations reveal rapid and widespread changes within coastal sites, an increasing diversification in overall subsistence resources, and patterns of increase in site establishment and use. Some of these changes have been argued to be associated with increasing climate variability and a trend towards increasing aridity during the late Holocene, thought to have transformed coastal ecosystems and mollusc availability. However, when these hypotheses are tested at the local level, more nuanced patterns of human-environment interaction emerge, which call into question interpretations based on broad-scale climate records. We suggest that disjunctions in the timing of the cessation of shell mound construction noted between the west and east Gulf of Carpentaria may be related, at least in part, to the timing and intensity of external cultural contacts with Macassan seafarers, associated with reorganization of mobility and production strategies, rather than as yet undemonstrated environmental changes impacting on shellfish availability.

Biomimetic Theory and Building Technology: Use of Aboriginal and Scientific Knowledge of Spinifex Grass

Abstract There is currently much interest in designing new materials that mimic particular properties of plants. For example, self-cleaning materials have been developed from structures on the leaf surface of sacred lotus, and new composite fibres are being designed from plants to replace metal structures. Biomimetic theory and its application, bio-inspired design, derive concepts from natural systems and appear to have potential to create new types of sustainable materials. The benefits of this approach seem to come from the linking of ethnographic and ecological research with building science to create and test new building technologies. Using spinifex as an example, it has been possible to develop some underlying principles to this approach to advance the methodology.

Understanding Isolation and Change in Island Human Populations through a study of Indigenous Cultural Patterns in the Gulf of Carpentaria

Abstract This paper presents a set of hypotheses to explain the cultural differences between Aboriginal people of the North and South Wellesley Islands, Gulf of Carpentaria and to characterise the relative degree and nature of their isolation and cultural change over a 10,000-year time-scale. This opportunity to study parallelisms and divergences in the cultural and demographic histories of fisher-hunter-gatherers arises from the comparison of three distinct cultural groupings: (a) the Ganggalida of the mainland, (b) the Lardil and Yangkaal of the North Wellesley Islands, and (c) the Kaiadilt of the South Wellesley Islands. Despite occupying similar island environments and despite their languages being as closely related as for example, the West Germanic languages, there are some major differences in cultural, economic and social organization as well as striking genetic differences between the North and South Wellesley populations. This paper synthesizes data from linguistics, anthropology, archaeology, genetics and environmental science to present hypotheses of how these intriguing differences were generated, and what we might learn about early processes of marine colonization and cultural change from the Wellesley situation.

Aboriginal signs and architectural meanings. Part 2: generating architectural signs. Architectural semiotics in designing for Aboriginal clients

The second part of this paper deals with a a number of particular designs for town plans and buildings which have been prepared for Aboriginal clients and which illustrate attempts to incorporate two- and three-dimensional signs relevant to Aboriginal culture. Although the designs were prepared for Aboriginal clients, the users were not necessarily Aboriginal people. This raises the issue of public meaning versus private meaning in architectural symbolism, and the difficulty of communicating public meaning through a buildings image without understanding inner cultural meaning. One has to differentiate the various categories of clients, gain understanding of their respective knowledge bases, then choose the messages to be communicated to each respective category, Aboriginal or non-Aboriginal or both, and design accordingly.