2,222 research outputs found
Support System Effects on the DLR-F6 Transport Configuration in the National Transonic Facility
An experimental investigation of the DLR-F6 generic transport configuration was conducted in the NASA NTF for use in the Drag Prediction Workshop. As data from this experimental investigation was collected, a large difference in drag values was seen between the NTF test and an ONERA test that was conducted several years ago. After much investigation, it was determined that this difference was likely due to a sting effect correction applied to the ONERA data which NTF does not use. This insight led to the present work. In this study, a computational assessment has been undertaken to investigate model support system interference effects on the DLR-F6 transport configuration. The configurations computed during this investigation were the isolated wing-body, the wing-body with the full support system (blade and sting), the wing-body with just the blade, and the wing-body with just the sting. The results from this investigation show the same trends that ONERA saw when they conducted a similar experimental investigation in the S2MA tunnel. Computational results suggest that the blade contributed an interference type of effect, the sting contributed a general blockage effect, and the full support system combined these effects
Evaluation of Sugar Cane Bagasse and Rice Straw as Process Substrates for the Production of Ethyl Alcohol
Spontaneous Fluxon Production in Annular Josephson Tunnel Junctions in the Presence of a Magnetic Field
We report on the spontaneous production of fluxons in the presence of a
symmetry-breaking magnetic field for annular Josephson tunnel junctions during
a thermal quench. The dependence on field intensity of the probability
to trap a single defect during the N-S phase transition drastically
depends on the sample circumferences. We show that the data can be understood
in the framework of the Kibble-Zurek picture of spontaneous defect formation
controlled by causal bounds.Comment: Submitted to Phys. Rev. B with 5 figures on Nov. 15, 200
Fluxoid formation: size effects and non-equilibrium universality
Simple causal arguments put forward by Kibble and Zurek suggest that the
scaling behaviour of condensed matter at continuous transitions is related to
the familiar universality classes of the systems at quasi-equilibrium. Although
proposed 25 years ago or more, it is only in the last few years that it has
been possible to devise experiments from which scaling exponents can be
determined and in which this scenario can be tested. In previous work, an
unusually high Kibble-Zurek scaling exponent was reported for spontaneous
fluxoid production in a single isolated superconducting Nb loop, albeit with
low density. Using analytic approximations backed up by Langevin simulations,
we argue that densities as small as these are too low to be attributable to
scaling, and are conditioned by the small size of the loop. We also reflect on
the physical differences between slow quenches and small rings, and derive some
criteria for these differences, noting that recent work on slow quenches does
not adequately explain the anomalous behaviour seen here.Comment: 7 pages, 4 figures, presentation given at CMMP 201
New Experiments for Spontaneous Vortex Formation in Josephson Tunnel Junctions
It has been argued by Zurek and Kibble that the likelihood of producing
defects in a continuous phase transition depends in a characteristic way on the
quench rate. In this paper we discuss an improved experiment for measuring the
Zurek-Kibble scaling exponent for the production of fluxons in
annular symmetric Josephson Tunnel Junctions. We find .
Further, we report accurate measurements of the junction gap voltage
temperature dependence which allow for precise monitoring of the fast
temperature variations during the quench.Comment: 12 pages, 5 figures, submitted to Phys. Rev.
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GAP WORK project report: training for youth practitioners on tackling gender-related violence
This project sought to challenge gender-related violence against (and by) children and young people by developing training for practitioners who have everyday contact with general populations of children and young people (‘youth practitioners’). Through improved knowledge and understanding practitioners can better identify and challenge sexist, sexualising, homophobic or controlling language and behaviour, and know when and how to refer children and young people to the most appropriate support services. This summary outlines the Project and our initial findings about the success of the four training programmes developed and piloted.Co-funded by the DAPHNE III programme of the EU
Winding Number Correlation Functions and Cosmic String Formation
We develop winding number correlation functions that allow us to assess the
role of field fluctuations on vortex formation in an Abelian gauge theory. We
compute the behavior of these correlation functions in simple circumstances and
show how fluctuations are important in the vicinity of the phase transition. We
further show that, in our approximation, the emerging population of
long/infinite string is produced by the classical dynamics of the fields alone,
being essentially unaffected by field fluctuations.Comment: Latex file, 27 pages. 8 figures, available in compressed form by
anonymous ftp from ftp://euclid.tp.ph.ic.ac.uk/papers/94-5_39.fig Latex and
postscript versions also available at
http://euclid.tp.ph.ic.ac.uk/Papers/index.htm
Experimental Investigation of the DLR-F6 Transport Configuration in the National Transonic Facility
An experimental aerodynamic investigation of the DLR (German Aerospace Center) F6 generic transport configuration has been conducted in the NASA NTF (National Transonic Facility) for CFD validation within the framework of the AIAA Drag Prediction Workshop. Force and moment, surface pressure, model deformation, and surface flow visualization data have been obtained at Reynolds numbers of both 3 million and 5 million. Flow-through nacelles and a side-of-body fairing were also investigated on this wing-body configuration. Reynolds number effects on trailing edge separation have been assessed, and the effectiveness of the side-of-body fairing in eliminating a known region of separated flow has been determined. Data obtained at a Reynolds number of 3 million are presented together for comparison with data from a previous wind tunnel investigation in the ONERA S2MA facility. New surface flow visualization capabilities have also been successfully explored and demonstrated in the NTF for the high pressure and moderately low temperature conditions required in this investigation. Images detailing wing surface flow characteristics are presented
The complexity of evaluating, categorising and quantifying marine cultural heritage
Despite the growing recognition that ecosystem-based management approaches to ocean governance need to recognise and integrate cultural dimensions to remain relevant, efficient, inclusive and equitable, the difficulty of meaningfully integrating these in ecosystem-based ocean management remains a challenge. This is particularly due to i) the difficulty of quantifying marine cultural heritage and cultural connections, ii) the complexity of identifying, evaluating and categorising ‘cultural ecosystem services’, particularly when it comes to intangible cultural heritage, and iii) the difficulty of spatially defining cultural heritage, connections and ecosystem services. There are several problems with current understandings and evaluations of marine cultural heritage, connections and cultural ecosystem services that first need to be addressed before attempting to quantify the social and cultural dimensions implicit in ecosystem-based ocean management. Challenges include the exclusion of some cultural 'services' that cannot be attributed an economic value because they are intangible, and the larger issue of Western-dominated conceptualisations, e.g., 'services’, 'ecosystems’, 'nature’, 'culture’. In this short communication we argue that the quantifying and simplification of marine cultural heritage and connections should be avoided altogether, as this can result in ecosystem collapse instead of ecosystem flourishing. The piece concludes by arguing that we need to qualify instead of quantify cultural dimensions of ecosystem-based ocean management, and develop contextual participatory research methodologies to better understand marine cultural heritage and cultural connections to marine social-ecological systems
Slow Quenches Produce Fuzzy, Transient Vortices
We examine the Zurek scenario for the production of vortices in quenches of
liquid in the light of recent experiments. Extending our previous
results to later times, we argue that short wavelength thermal fluctuations
make vortices poorly defined until after the transition has occurred. Further,
if and when vortices appear, it is plausible that that they will decay faster
than anticipated from turbulence experiments, irrespective of quench rates.Comment: 4 pages, Revtex file, no figures Apart from a more appropriate title,
this paper differs from its predecessor by including temperature, as well as
pressure, quenche
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