70,861 research outputs found
Opportunities for use of exact statistical equations
Exact structure function equations are an efficient means of obtaining
asymptotic laws such as inertial range laws, as well as all measurable effects
of inhomogeneity and anisotropy that cause deviations from such laws. "Exact"
means that the equations are obtained from the Navier-Stokes equation or other
hydrodynamic equations without any approximation. A pragmatic definition of
local homogeneity lies within the exact equations because terms that explicitly
depend on the rate of change of measurement location appear within the exact
equations; an analogous statement is true for local stationarity. An exact
definition of averaging operations is required for the exact equations. Careful
derivations of several inertial range laws have appeared in the literature
recently in the form of theorems. These theorems give the relationships of the
energy dissipation rate to the structure function of acceleration increment
multiplied by velocity increment and to both the trace of and the components of
the third-order velocity structure functions. These laws are efficiently
derived from the exact velocity structure function equations. In some respects,
the results obtained herein differ from the previous theorems. The
acceleration-velocity structure function is useful for obtaining the energy
dissipation rate in particle tracking experiments provided that the effects of
inhomogeneity are estimated by means of displacing the measurement location.Comment: accepted by Journal of Turbulenc
Current activities at IITRI on high- temperature protective coatings
Heat resistant protective coatings for use in liquid propellant rocket engine
Incommensurate chirality density wave transition in a hybrid molecular framework
Using single-crystal X-ray diffraction we characterise the 235\,K
incommensurate phase transition in the hybrid molecular framework
tetraethylammonium silver(I) dicyanoargentate, [NEt]Ag(CN). We
demonstrate the transition to involve spontaneous resolution of chiral
[NEt] conformations, giving rise to a state in which molecular
chirality is incommensurately modulated throughout the crystal lattice. We
refer to this state as an incommensurate chirality density wave (XDW) phase,
which represents a fundamentally new type of chiral symmetry breaking in the
solid state. Drawing on parallels to the incommensurate ferroelectric
transition of NaNO we suggest the XDW state arises through coupling between
acoustic (shear) and molecular rotoinversion modes. Such coupling is
symmetry-forbidden at the Brillouin zone centre but symmetry-allowed for small
but finite modulation vectors . The importance of
long-wavelength chirality modulations in the physics of this hybrid framework
may have implications for the generation of mesoscale chiral textures, as
required for advanced photonic materials.Comment: 5 pages, 3 figure
Interacting with digital media at home via a second screen
In recent years Interactive Television (iTV) has become a household technology on a global scale. However, iTV is still a new technology in the early stages of its evolution.
Our previous research looked at how everyday users of iTV feel about the interactive part of iTV. In a series of studies we investigated how people use iTV services; their likes, dislikes, preferences and opinions. We then developed a second screen-based prototype device in response to these findings and tested it with iTV users in their own homes. This is a work in progress paper that outlines the work carried previously in the area of controlling interactive Television via a second screen. The positive user responses led us to extend the scope of our previous research to look into other related areas such as barriers to digital interactive media and personalisation of digital interactive media at home
Demonstration of non-Markovian process characterisation and control on a quantum processor
In the scale-up of quantum computers, the framework underpinning
fault-tolerance generally relies on the strong assumption that environmental
noise affecting qubit logic is uncorrelated (Markovian). However, as physical
devices progress well into the complex multi-qubit regime, attention is turning
to understanding the appearance and mitigation of correlated -- or
non-Markovian -- noise, which poses a serious challenge to the progression of
quantum technology. This error type has previously remained elusive to
characterisation techniques. Here, we develop a framework for characterising
non-Markovian dynamics in quantum systems and experimentally test it on
multi-qubit superconducting quantum devices. Where noisy processes cannot be
accounted for using standard Markovian techniques, our reconstruction predicts
the behaviour of the devices with an infidelity of . Our results show
this characterisation technique leads to superior quantum control and extension
of coherence time by effective decoupling from the non-Markovian environment.
This framework, validated by our results, is applicable to any controlled
quantum device and offers a significant step towards optimal device operation
and noise reduction
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Clothing longevity perspectives: exploring consumer expectations, consumption and use
The production, distribution, use and end-of-life phases of the clothing lifecycle all have significant environmental impacts, but complete lifecycle assessment has identified that extending the active life of garments through design, use and re-use is the single most effective intervention in reducing the overall impact of the clothing industry (WRAP, 2011). In response, Government funded clothing longevity research seeks to develop and test industry-led design strategies to influence and enable consumers to keep garments in active use for longer (Cooper et al., 2014). While recent UK research has indicated significant potential to influence more sustainable consumer behaviour (Langley et al., 2013; YouGov, 2012), up-to-date qualitative research is required to discover how consumer attitudes, expectations and behaviours in relation to clothing lifetimes affects garment care and clothing use. This will help to inform industry-led strategies by understanding where effective changes can be made that will potentially have most impact. This paper presents preliminary findings from a Defra funded action based research project, ‘Strategies to improve design and testing for clothing longevity’. Qualitative research methods are used to explore consumer attitudes, expectations and behaviours at purchase, use and disposal stages of garment lifetimes, and gather data on practices of garment wash, wear, care and maintenance in everyday life. The research findings are discussed in relation to industry-led strategies aimed at extending the life of clothes
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