Fabrication and mechanical and thermal behaviour of graphene oxide/epoxy nanocomposites

Bulk amount of graphite oxide was prepared by oxidation of graphite using the modified Hummers method and its ultrasonication in organic solvents yielded graphene oxide (GO). X-ray diffraction (XRD) pattern, X-ray photoelectron (XPS), Raman and Fourier transform infrared (FTIR) spectroscopy indicated the successful preparation of GO. XPS survey spectrum of GO revealed the presence of 66.6 at% C and 30.4 at% O. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images of the graphene oxide showed that they consist of a large amount of graphene oxide platelets with a curled morphology containing of a thin wrinkled sheet like structure. AFM image of the exfoliated GO signified that the average thickness of GO sheets is ~1.0 nm which is very similar to GO monolayer. GO/epoxy nanocomposites were prepared by typical solution mixing technique and influence of GO on mechanical and thermal properties of nanocomposites were investigated. As for the mechanical behaviour of GO/epoxy nanocomposites, 0.5 wt% GO in the nanocomposite achieved the maximum increase in the elastic modulus (~35%) and tensile strength (~7%). The TEM analysis provided clear image of microstructure with homogeneous dispersion of GO in the polymer matrix. The improved strength properties of GO/epoxy nanocomposites can be attributed to inherent strength of GO, the good dispersion and the strong interfacial interactions between the GO sheets and the polymer matrix. However, incorporation of GO showed significant negative effect on composite glass transition temperature (Tg). This may arise due to the interference of GO on curing reaction of epoxy.

Correlating flow induced shear stress and chondrocytes activity in micro-porous scaffold using computational fluid dynamics and rapid prototyping

Flow induced shear stress plays an important role in regulating cell growth and distribution in scaffolds. This study sought to correlate wall shear stress and chondrocytes activity for engineering design of micro-porous osteochondral grafts based on the hypothesis that it is possible to capture and discriminate between the transmitted force and cell response at the inner irregularities. Unlike common tissue engineering therapies with perfusion bioreactors in which flow-mediated stress is the controlling parameter, this work assigned the associated stress as a function of porosity to influence in vitro proliferation of chondrocytes. D-optimality criterion was used to accommodate three pore characteristics for appraisal in a mixed level fractional design of experiment (DOE); namely, pore size (4 levels), distribution pattern (2 levels) and density (3 levels). Micro-porous scaffolds (n=12) were fabricated according to the DOE using rapid prototyping of an acrylic-based bio-photopolymer. Computational fluid dynamics (CFD) models were created correspondingly and used on an idealized boundary condition with a Newtonian fluid domain to simulate the dynamic microenvironment inside the pores. In vitro condition was reproduced for the 3D printed constructs seeded by high pellet densities of human chondrocytes and cultured for 72 hours. The results showed that cell proliferation was significantly different in the constructs (p<0.05). Inlet fluid velocity of 3×10-2mms-1 and average shear stress of 5.65×10-2 Pa corresponded with increased cell proliferation for scaffolds with smaller pores in hexagonal pattern and lower densities. Although the analytical solution of a Poiseuille flow inside the pores was found insufficient for the description of the flow profile probably due to the outside flow induced turbulence, it showed that the shear stress would increase with cell growth and decrease with pore size. This correlation demonstrated the basis for determining the relation between the induced stress and chondrocyte activity to optimize microfabrication of engineered cartilaginous constructs.

Aboriginal dietary intake and a successful nutrition intervention project in a Northern Territory community

This paper summarises the development and testing of the 'store-turnover' method, a non-invasive dietary survey methodology for quantitative measurement of food and nutrient intake in remote, centralised Aboriginal communities. It then describes the use of the method in planning, implementation and evaluation of a community-based nutrition intervention project in a small Aboriginal community in the Northern Territory. During this project marked improvements in both the dietary intake of the community and biological indicators of nutritional health (including vitamin status and the degree and prevalence of several risk factors for non-communicable disease) were measured in the community over a 12-month period following the development of intervention strategies with the community. Although these specific strategies are presented, emphasis is directed towards the process involved, particularly the evaluation procedures used to monitor all stages of the project with the community.

Identity orientation and stakeholder engagement—the corporatisation of elite schools

Identity orientation provides a means to understand the social motivations of organisational relationships and organisational policy and practices. This study uses identity orientation to understand the highly marketised context of independent ‘elite’ schools in Australia and how they relate to stakeholders to straddle their roles as social institutions that are increasingly required to operate in a corporate manner. Interviews with managers in quite new school roles such as marketing communication and business management were conducted in non-government schools to understand the schools' external orientations, coveted internal member traits, and frames of reference. The study shows that, in contrast to existing literature on the rhetoric of schools as focusing on ‘the child’, there was a strong emphasis on individualistic orientations in schools that saw stakeholders in instrumental terms of resources and connections, saw teachers as providing an innovative and leading edge, and used other prestigious schools as their frame of reference. To a lesser extent, schools would also be interested in the relationships with families, teachers, and the community for their own means. There were very few instances where the identity orientation was contributing to society, instead, focusing on university and network outcomes for pupils. Using identity orientation provides a theoretical lens to connect organisational governance to stakeholder engagement by providing insights into an organisation's identity including practices and behaviours, in relation to others.

Locating delamination in composite laminated beams using the A0 Lamb mode

In this study, experimental and numerical investigations have been conducted to explore the possibility of using A0 mode in Lamb waves to detect the position of delamination in carbon fiber reinforced plastic (CFRP) laminated beams. An experimental technique for exciting and sensing the pure A0 mode has been developed. By measuring the propagation speed of A0 mode and traveling time of a signal reflected from the delamination, its location can be identified experimentally and numerically. Moreover, the numerical analysis has been extended to gain a better understanding of the complex interaction between A0 mode and a long delamination case.

In-situ combustion synthesis of ultrafine TiB2 particles reinforced Cu matrix composite

Due to the lower strength of pure copper (Cu), ceramic particulate or whisker reinforced Cu matrix composites have attracted wide interest in recent years [1–3]. These materials exhibit a combination of excellent thermal and electrical conductivities, high strength retention at elevated temperatures, and high microstructural stability [3]. The potential applications include various electrodes, electrical switches, and X-ray tube components [4].

Self-determination as a moderator of demands and control : implications for employee strain and engagement

Does job control act as a stress-buffer when employees' type and level of work self-determination is taken into account? It was anticipated that job control would only be stress-buffering for employees high in self-determined and low in non-self-determined work motivation. In contrast, job control would be stress-exacerbating for employees who were low in self-determined and high in non-self-determined work motivation. Employees of a health insurance organization (N = 123) completed a survey on perceptions of role overload, job control, work self-determination, and a range of strain and engagement indicators. Results revealed that, when individuals high in self-determination perceived high job control, they experienced greater engagement (in the form of dedication to their work). In addition, when individuals high in non-self-determination perceived high job demands, they experienced more health complaints. A significant 3-way interaction demonstrated that, for individuals low in non-self-determination, high job control had the anticipated stress-buffering effect on engagement (in the form of absorption in their work). In addition, low job control was stress-exacerbating. However, contrary to expectations, for those high in non-self-determination, high job control was just as useful as low job control as a stress-buffer. The practical applications of these findings to the organizational context are discussed.

Team change climate : a group-level analysis of the relationships among change information and change participation, role stressors, and well-being

We explored whether teams develop shared perceptions regarding the quantity and quality of information and the extent of participation in decision making provided in an environment of continuous change. In addition, we examined whether change climate strength moderated relationships between change climate level and team outcomes. We examined relationships among aggregated change information and change participation and aggregated team outcomes, including two role stressors (i.e., role ambiguity and role overload) and two indicators of well-being (i.e., quality of worklife and distress). Questionnaires were distributed in an Australian law enforcement agency and data were used from 178 teams. Structural equation modelling analyses, controlling for a marker variable, were conducted to examine the main effects of aggregated change information and aggregated change participation on aggregated team outcomes. Results provided support for a model that included method effects due to a marker variable. In this model, change information climate was significantly negatively associated with role ambiguity, role overload, and distress, and significantly positively associated with quality of worklife. Change participation climate was significantly positively associated with quality of worklife. Change climate strength did not moderate relationships among change climate level and team outcomes.

Transnational distance education : cultural and quality considerations

There have now been two decades of rhetoric on the need for culturally and contextually appropriate perspectives in international education. However, the extent to which courses, provision and pedagogy have truly reflected differences in cultural characteristics and learning preferences is still open to question. Little attention has been paid to these matters in quality assurance frameworks. This chapter discusses these issues and draws upon Hofstede’s cultural dimensions framework and studies into Asian pedagogy and uses of educational technology. It proposes a benchmark and performance indicators for assuring cultural, contextual, educational and technological appropriateness in the provision of transnational distance education in Asia by Australian universities.

Numerical investigation into the buckling behavior of advanced grid stiffened composite cylindrical shell

Advanced grid stiffened composite cylindrical shell is widely adopted in advanced structures due to its exceptional mechanical properties. Buckling is a main failure mode of advanced grid stiffened structures in engineering, which calls for increasing attention. In this paper, the buckling response of advanced grid stiffened structure is investigated by three different means including equivalent stiffness model, finite element model and a hybrid model (H-model) that combines equivalent stiffness model with finite element model. Buckling experiment is carried out on an advanced grid stiffened structure to validate the efficiency of different modeling methods. Based on the comparison, the characteristics of different methods are independently evaluated. It is arguable that, by considering the defects of material, finite element model is a suitable numerical tool for the buckling analysis of advanced grid stiffened structures.

Characterising and predicting cyber attacks using the Cyber Attacker Model Profile (CAMP)

Purpose Ethnographic studies of cyber attacks typically aim to explain a particular profile of attackers in qualitative terms. The purpose of this paper is to formalise some of the approaches to build a Cyber Attacker Model Profile (CAMP) that can be used to characterise and predict cyber attacks. Design/methodology/approach The paper builds a model using social and economic independent or predictive variables from several eastern European countries and benchmarks indicators of cybercrime within the Australian financial services system. Findings The paper found a very strong link between perceived corruption and GDP in two distinct groups of countries – corruption in Russia was closely linked to the GDP of Belarus, Moldova and Russia, while corruption in Lithuania was linked to GDP in Estonia, Latvia, Lithuania and Ukraine. At the same time corruption in Russia and Ukraine were also closely linked. These results support previous research that indicates a strong link between been legitimate economy and the black economy in many countries of Eastern Europe and the Baltic states. The results of the regression analysis suggest that a highly skilled workforce which is mobile and working in an environment of high perceived corruption in the target countries is related to increases in cybercrime even within Australia. It is important to note that the data used for the dependent and independent variables were gathered over a seven year time period, which included large economic shocks such as the global financial crisis. Originality/value This is the first paper to use a modelling approach to directly show the relationship between various social, economic and demographic factors in the Baltic states and Eastern Europe, and the level of card skimming and card not present fraud in Australia.

20 Years of pacifying responses to environmental management

Using a state, pressure, response framework, we provide an evidence-based reflection on environmental outcomes in Australia and New Zealand across the domains of climate change, biodiversity, freshwater and marine management, emphasising the role of Indigenous and business perspectives. Significant developments have occurred in the past 20 years through affirmation of Indigenous rights and responsibilities. Responses to climate change have tended to emphasise passive risk management with unclear outcomes. Despite meeting biodiversity protection targets, outcomes are worsening, suggesting a need to challenge the dualistic preservation/production land categorisations. In freshwater and marine management, a mix of collaborative and market-based responses has emerged, although their efficacy remains untested. A reliance on voluntary approaches by business makes critical assessment of progress difficult. Thus, despite strong progress in some areas, the adaptiveness of environmental management remains limited, and many indicators suggest continuing decline in environmental condition. Our responses have been largely pacifying in nature, leading to perverse outcomes and failure to acknowledge alternatives that might address deteriorating environmental conditions. A shift is needed towards deliberative policy experimentation that truly values the application of novel and diversified approaches and facilitates integrated learning across environmental domains.

Nilotinib and MEK inhibitors induce synthetic lethality through paradoxical activation of RAF in drug-resistant chronic myeloid leukemia

We show that imatinib, nilotinib, and dasatinib possess weak off-target activity against RAF and, therefore, drive paradoxical activation of BRAF and CRAF in a RAS-dependent manner. Critically, because RAS is activated by BCR-ABL, in drug-resistant chronic myeloid leukemia (CML) cells, RAS activity persists in the presence of these drugs, driving paradoxical activation of BRAF, CRAF, MEK, and ERK, and leading to an unexpected dependency on the pathway. Consequently, nilotinib synergizes with MEK inhibitors to kill drug-resistant CML cells and block tumor growth in mice. Thus, we show that imatinib, nilotinib, and dasatinib drive paradoxical RAF/MEK/ERK pathway activation and have uncovered a synthetic lethal interaction that can be used to kill drug-resistant CML cells in vitro and in vivo.

Poverty and non-communicable diseases in South Africa

Background: High levels of wealth inequality with improved health statistics in South Africa (SA) provide an important opportunity to investigate non-communicable diseases (NCDs) among the poor. Aims: This paper uses two distinct national data sets to contrast patterns of mortality in rich and poor areas and explore the associations between poverty, risk factors, health care and selected NCDs diseases in South African adults. Methods: Causes of premature mortality in 1996 experienced in the poorest magisterial districts are compared with those in the richest, using average household wealth to classify districts. Logistic and multinomial regression are used to investigate the association of a household asset index and selected chronic conditions, related risk factors and healthcare indicators using data from the 1998 South African Demographic and Health Survey. Results: NCDs accounted for 39% and 33% of premature mortality in rich and poor districts respectively. The household survey data showed that the risk factors hypertension and obesity increased with increasing wealth, while most of the lifestyle factors, such as light smoking, domestic exposure to ``smoky'' fuels and alcohol dependence were associated with poverty. Treatment status for hypertension and asthma was worse for poor people than for rich people. Conclusions: The study suggests that NCDs and lifestyle-related risk factors are prevalent among the poor in SA and treatment for chronic diseases is lacking for poor people. The observed increase in hypertension and obesity with wealth suggests that unless comprehensive health promotion strategies are implemented, there will be an unmanageable chronic disease epidemic with future socioeconomic development in SA.

The innovation imperative: The relationships between team climate, innovation, and performance in research and development teams

A team’s climate for innovation has been shown to be important for innovation in management and work teams. This article investigates the relationship of team climate with project team innovation and performance in research and development organizations. It is argued that the relationship between team climate and innovation will be stronger for research teams than development teams as research teams have greater scope for creating novel and innovative ideas. A sample of 193 scientists and technologists in 20 research teams and 18 development teams were measured on their team’s climate for innovation, team performance, and six indicators of innovation. Research and development teams showed similar ratings for team climate and for measures of innovation. However, the relationships between team climate and individual and team innovation were stronger for research teams than development teams. These findings are significant for fostering innovativeness and innovation in knowledge work teams.