Prediction of crushing stress in composite materials

A simple mathematical model for predicting the crushing stress of composite materials was derived and presented in this paper. The present knowledge of fracture mechanics and strength of materials are used as the basis for the model. The fracture mechanics part of the analysis was based on energy release rate approach; the energy release rate, G, of the proposed model was determined by this approach. This energy release rate was based on the Mode I (opening or tensile mode) failure. As for the strength of materials part analysis, buckling theory was used to determine the critical load of the fibre beams. These two engineering concepts were combined to form the equation for the proposed model. The derived equation is a function of the materials properties, geometric and physical parameters of the composite materials. The calculated stresses from the derived equation were compared with experimental data from technical and research papers. Good agreements shown in the results are encouraging and recommendations for future analysis with different modes of failure were also presented. This paper enables engineering designers to predict crushing stress in composite materials with confidence and makes their work more efficient and reliable

Revised Fowler-Dubridge model for photoelectron emission from two-dimensional materials

We revise the Fowler-Dubridge (FB) model for photoelectron emission from two-dimensional (2D) materials to include the effects of reduced dimensionality, non-parabolic and anisotropic energy dispersion of 2D materials. Two different directions of electron emission are studied, namely vertical emission from the surface and lateral emission from the edge. Our analytical model reveals a universal temperature scaling of T\b{eta} with \b{eta} = 1 and \b{eta} = 3/2, respectively, for the surface and edge emission over a wide class of 2D materials, which are distinct from the traditional scaling of \b{eta} = 2 originally derived for the traditional bulk materials. Our comparison shows good agreement to two experiments of photo-electron emitted from graphene for both surface and edge emission. Our calculations also show the photoelectron emission is more pronounced than the coexisting thermionic emission for materials with low temperature and Fermi energy. This model provides helpful guidance in choosing proper combinations of light intensity, temperature range and type of 2D materials for the design of photoemitters, photodetectors and other optoelectronicsComment: 6 pages, 4 figure

A systematic policy review of early childhood development and peacebuilding in fourteen conflict-affected and post-conflict countries: final report

This report presents the findings of a systematic review of early childhood development (ECD) and peacebuilding policies across 14conflict-affected and post-conflict countries. The study sought to map existing national-level policies covering a range of crosssectors: ECD, peacebuilding and social welfare policies. Overall, the findings show ‘policy gaps’ across all 14 countries in the recognition of the importance of early childhood development. There are also limited linkages in the policy discourses between early childhood development and peacebuilding. Yet, there is some empirical and policy evidence which show the effectiveness of early childhood development and education in promoting positive changes in young children’s lives and their potential contributions to social cohesion and reconciliation in conflict-affected states. The review shows compelling reasons for increased prioritisation of the early years and ECD in policy development in the promotion of peacebuilding

Control of atom-photon interactions with shaped quantum electron wavepackets

Photon emission from atoms and free electrons underlie a wealth of fundamental science and technological innovations. We present a regime where atom-photon and electron-photon interactions interfere with each other, resulting in substantial changes in the spontaneous emission rate compared to the sum of each interaction considered in isolation. We highlight the critical role played by quantum electron wavepackets, and how the emission can be tailored via the electron waveshape, as well as the atomic population and coherence. Our findings reveal that atom-photon and electron-photon interactions cannot be considered in isolation even when higher-order contributions involving all three bodies (atom, photon and free electron) are negligible. Our findings pave the way to more precise control over photon emission processes and related diagnostics.Comment: 9 pages, 4 figure

An update of the JPL program to develop Li-SOCl2 cells

The goal of producing spiral wound D cell was met. The cell design and electrodes, particularly the carbon cathodes were produced in-house. Also all parts were assembled, the welding performed, the electrolyte aided and the cells sealed in-house. The lithium capacity (theoretical) was 19.3 Ah and that of the SOCl2 in the 1.8 m LiAlCl4 electrolyte, 16.4 Ah (a greater excess of SOCl2 is necessary for safe high rate operation). The electrode surface area was 452 sq cm. The carbon electrode comprised Shawinigen Black/Teflon -30 (90/10 by weight) mixture 0.020 inches thick on an expanded metal screen prepared in the JPL laboratory. There were two tab connections to the cathode. The 0.0078 inch thick lithium foil was rolled into an expanded nickel screen. The separator was Mead 934-5 fiberglass material

\u27Kids in design\u27: designing creative schools with children

There is a consensus that children should be involved in the planning and design process of their schools, and attempts have been made throughout the world. This paper introduces a \u27Kids in Design\u27 project, through which primary school children worked with university architecture students to design a school playground. The aim of the project was to encourage the full potential of children\u27s creativity and generate creative school design outcomes. From October to December 2011, the \u27Kids in Design\u27 project was conducted in Roslyn Road Primary School (Geelong, Australia). Through eight weeks of workshops, children in Year 5 & 6 worked with architecture students from Deakin University (Geelong, Australia) to design a school playground. Assessing the design outcomes of this project, assertions are made that creative design outcomes have been achieved. Deakin University is currently working with another primary school to replicate the \u27Kids in Design\u27 project in 2012