378 research outputs found
A Hero's Journey': using codesign to develop a fine motor skills video game with and for children with Developmental Coordination Disorder (DCD)
Developmental Coordination Disorder (DCD), is a neurological disorder that among other things affects fine and gross motor coordination in around 5-6% of school-aged children worldwide. Despite research indicating the effectiveness of digital technology in supporting children with DCD, digital tools such as video games have not yet broken into mainstream DCD support. This project developed a video game-based support for children with DCD through a co-design process. This co-design process had two facets, firstly I worked with adult expert participants to develop ideas for how video games could be used as support for children with DCD, conducting a series of interviews with experts in supporting children with DCD, secondly I worked with 5 children with DCD to co-design key elements of a video game, including character, story and user interfaces, as a way to ensure that the developed game developed is not only effective but something that children with DCD would want to use and enjoy. Using this process, a game was developed to challenge and improve fine motor skills through a series of different interactions. The game was evaluated by 8 teachers, who reported that the game was effective, valuable and something they could use in schools
Development of a GPS/GPRS prompted-recall solution for longitudinal driving behaviour studies
This paper details the development of a GPS/GPRS data collection solution for a longitudinal (twelve week) study of driving behaviour in Sydney, investigating behavioural responses to variable rate charging. The study calls for data to be regularly downloaded to check the quality of data as it is being collected and provide the basis for a web-based prompted recall (PR) survey in which participants can view their trips, confirm details and provide information on who was driving, number of passengers and trip purpose. Following details of the technological setup, we detail the data processing issues involved and the development of the PR survey. Pilot testing of the approach on thirty motorists demonstrates that contrary to popular belief, data of this nature can be collected for several weeks with little respondent burden at high levels of accuracy
Aerodynamic levitator furnace for measuring thermophysical properties of refractory liquids
The development of novel contactless aerodynamic laser heated levitation techniques is reported that enable thermophysical properties of refractory liquids to be measured in situ in the solid, liquid, and supercooled liquid state and demonstrated here for alumina. Starting with polished crystalline ruby spheres, we show how, by accurately measuring the changing radius, the known density in the solid state can be reproduced from room temperature to the melting point at 2323 K. Once molten, by coupling the floating liquid drop to acoustic oscillations via the levitating gas, the mechanical resonance and damping of the liquid can be measured precisely with high-speed high-resolution shadow cast imaging. The resonance frequency relates to the surface tension, the decay constant to the viscosity, and the ellipsoidal size and shape of the levitating drop to the density. This unique instrumentation enables these related thermophysical properties to be recorded in situ over the entire liquid and supercooled range of alumina, from the boiling point at 3240 K, until spontaneous crystallization occurs around 1860 K, almost 500 below the melting point. We believe that the utility that this unique instrumentation provides will be applicable to studying these important properties in many other high temperature liquids
Modeling Collisional Cascades In Debris Disks: Steep Dust-Size Distributions
We explore the evolution of the mass distribution of dust in
collision-dominated debris disks, using the collisional code introduced in our
previous paper. We analyze the equilibrium distribution and its dependence on
model parameters by evolving over 100 models to 10 Gyr. With our numerical
models, we confirm that systems reach collisional equilibrium with a mass
distribution that is steeper than the traditional solution by Dohnanyi (1969).
Our model yields a quasi steady-state slope of n(m) ~ m^{-1.88} [n(a) ~
a^{-3.65}] as a robust solution for a wide range of possible model parameters.
We also show that a simple power-law function can be an appropriate
approximation for the mass distribution of particles in certain regimes. The
steeper solution has observable effects in the submillimeter and millimeter
wavelength regimes of the electromagnetic spectrum. We assemble data for nine
debris disks that have been observed at these wavelengths and, using a
simplified absorption efficiency model, show that the predicted slope of the
particle mass distribution generates SEDs that are in agreement with the
observed ones.Comment: 12 pages, 10 figures, Accepted by ApJ, emulateap
Percolation channels:A universal idea to describe the atomic structure and dynamics of glasses and melts
Understanding the links between chemical composition, nano-structure and the dynamic properties of silicate melts and glasses is fundamental to both Earth and Materials Sciences. Central to this is whether the distribution of mobile metallic ions is random or not. In silicate systems, such as window glass, it is well-established that the short-range structure is not random but metal ions cluster, forming percolation channels through a partly broken network of corner-sharing SiO4 tetrahedra. In alumino-silicate glasses and melts, extensively used in industry and representing most of the Earth magmas, metal ions compensate the electrical charge deficit of AlO4? tetrahedra, but until now clustering has not been confirmed. Here we report how major changes in melt viscosity, together with glass Raman and Nuclear Magnetic Resonance measurements and Molecular Dynamics simulations, demonstrate that metal ions nano-segregate into percolation channels, making this a universal phenomenon of oxide glasses and melts. Furthermore, we can explain how, in both single and mixed alkali compositions, metal ion clustering and percolation radically affect melt mobility, central to understanding industrial and geological processespublishersversionPeer reviewe
Resolved Debris Discs Around A Stars in the Herschel DEBRIS Survey
The majority of debris discs discovered so far have only been detected
through infrared excess emission above stellar photospheres. While disc
properties can be inferred from unresolved photometry alone under various
assumptions for the physical properties of dust grains, there is a degeneracy
between disc radius and dust temperature that depends on the grain size
distribution and optical properties. By resolving the disc we can measure the
actual location of the dust. The launch of Herschel, with an angular resolution
superior to previous far-infrared telescopes, allows us to spatially resolve
more discs and locate the dust directly. Here we present the nine resolved
discs around A stars between 20 and 40 pc observed by the DEBRIS survey. We use
these data to investigate the disc radii by fitting narrow ring models to
images at 70, 100 and 160 {\mu}m and by fitting blackbodies to full spectral
energy distributions. We do this with the aim of finding an improved way of
estimating disc radii for unresolved systems. The ratio between the resolved
and blackbody radii varies between 1 and 2.5. This ratio is inversely
correlated with luminosity and any remaining discrepancies are most likely
explained by differences to the minimum size of grain in the size distribution
or differences in composition. We find that three of the systems are well fit
by a narrow ring, two systems are borderline cases and the other four likely
require wider or multiple rings to fully explain the observations, reflecting
the diversity of planetary systems.Comment: 19 pages, 13 figures, 6 tables. Accepted for publication in MNRA
The debris disk around gamma Doradus resolved with Herschel
We present observations of the debris disk around gamma Doradus, an F1V star,
from the Herschel Key Programme DEBRIS (Disc Emission via Bias-free
Reconnaissance in the Infrared/Submillimetre). The disk is well-resolved at 70,
100 and 160 micron, resolved along its major axis at 250 micron, detected but
not resolved at 350 micron, and confused with a background source at 500
micron. It is one of our best resolved targets and we find it to have a
radially broad dust distribution. The modelling of the resolved images cannot
distinguish between two configurations: an arrangement of a warm inner ring at
several AU (best-fit 4 AU) and a cool outer belt extending from ~55 to 400 AU
or an arrangement of two cool, narrow rings at ~70 AU and ~190 AU. This
suggests that any configuration between these two is also possible. Both models
have a total fractional luminosity of ~10^{-5} and are consistent with the disk
being aligned with the stellar equator. The inner edge of either possible
configuration suggests that the most likely region to find planets in this
system would be within ~55 AU of the star. A transient event is not needed to
explain the warm dust's fractional luminosity.Comment: 12 pages, 6 figures, accepted for publication in Ap
A candidate fusion engineering material, WC-FeCr
A new candidate fusion engineering material, WC-FeCr, has been irradiated with He ions at 25 and 500 °C. Ions were injected at 6 keV to a dose of ~15 dpa and 50 at. % He, simulating direct helium injection from the plasma. The microstructural evolution was continuously characterised in situ using transmission electron microscopy. In the FeCr phase, a coarse array of 3–6 nm bubbles formed. In the WC, bubbles were less prominent and smaller (~2 nm). Spherical-cap bubbles formed at hetero-phase interfaces of tertiary precipitates, indicating that enhanced processing routes to minimise precipitation could further improve irradiation tolerance
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