92,873 research outputs found
Wavy-ply sandwich with composite skins and crushable core for ductility and energy absorption
Conventional composite materials offer high specific stiffness and strength, but suffer from low failure strains and failure without warning. This work proposes a new design for sandwich structures with symmetrically-wavy composite skins and a crushable foam core, aiming to achieve large strains (due to unfolding of the skins) and energy absorption (due to crushing of the foam core) under tensile loading. The structure is designed by a combination of analytical modelling and finite element simulations, and the concept is demonstrated experimentally. When loaded under quasi-static tension, wavy-ply sandwich specimens with carbonâepoxy skins and optimised geometry exhibited an average failure strain of 8.6%, a specific energy dissipated of 9.4 kJ/kg, and ultimate strength of 1570 MPa. The scope for further developing the wavy-ply sandwich concept and potential applications requiring large deformations and energy absorption are discussed
'Working our way to health': Final Evaluation Report
This summary presents the findings of an independent evaluation of the âWorking our Way to Healthâ programme. This programme was delivered by Sefton PCT, funded through the Neighbourhood Renewal Fund, and was aimed at improving the health of men in three of the most deprived wards in its locality. It aimed to encourage men to be health aware and increase access to health and leisure services in order to improve key lifestyle behaviours and advance gender equity. The programme included: âą Community agency and health staff training âą Peer mentoring programme âą Healthy lifestyle programme It aimed to promote community partnerships to assist the expansion of health advice and services into a new community arena and engage a previously unattainable section of the male population in healthier lifestyle interventions
A SAM Based Global CGE Model using GTAP Data January 2005
This paper provides a technical description of a global computable general equilibrium (CGE) model that is calibrated from a Social Accounting Matrix (SAM) representation of the Global Trade Analysis Project (GTAP) database. A distinctive feature of the model is the treatment of nominal and real exchange rates and hence the specification of multiple numéraire
A new algorithm for microwave delay estimation from water vapor radiometer data
A new algorithm has been developed for the estimation of tropospheric microwave path delays from water vapor radiometer (WVR) data, which does not require site and weather dependent empirical parameters to produce high accuracy. Instead of taking the conventional linear approach, the new algorithm first uses the observables with an emission model to determine an approximate form of the vertical water vapor distribution which is then explicitly integrated to estimate wet path delays, in a second step. The intrinsic accuracy of this algorithm has been examined for two channel WVR data using path delays and stimulated observables computed from archived radiosonde data. It is found that annual RMS errors for a wide range of sites are in the range from 1.3 mm to 2.3 mm, in the absence of clouds. This is comparable to the best overall accuracy obtainable from conventional linear algorithms, which must be tailored to site and weather conditions using large radiosonde data bases. The new algorithm's accuracy and flexibility are indications that it may be a good candidate for almost all WVR data interpretation
Intrinsic Variability and Field Statistics for the Vela Pulsar: 2. Systematics and Single-Component Fits
Individual pulses from pulsars have intensity-phase profiles that differ
widely from pulse to pulse, from the average profile, and from phase to phase
within a pulse. Widely accepted explanations do not exist for this variability
or for the mechanism producing the radiation. The variability corresponds to
the field statistics, particularly the distribution of wave field amplitudes,
which are predicted by theories for wave growth in inhomogeneous media. This
paper shows that the field statistics of the Vela pulsar (PSR B0833-45) are
well-defined and vary as a function of pulse phase, evolving from Gaussian
intensity statistics off-pulse to approximately power-law and then lognormal
distributions near the pulse peak to approximately power-law and eventually
Gaussian statistics off-pulse again. Detailed single-component fits confirm
that the variability corresponds to lognormal statistics near the peak of the
pulse profile and Gaussian intensity statistics off-pulse. The lognormal field
statistics observed are consistent with the prediction of stochastic growth
theory (SGT) for a purely linear system close to marginal stability. The
simplest interpretations are that the pulsar's variability is a direct
manifestation of an SGT state and the emission mechanism is linear (either
direct or indirect), with no evidence for nonlinear mechanisms like
modulational instability and wave collapse which produce power-law field
statistics. Stringent constraints are placed on nonlinear mechanisms: they must
produce lognormal statistics when suitably ensemble-averaged. Field statistics
are thus a powerful, potentially widely applicable tool for understanding
variability and constraining mechanisms and source characteristics of coherent
astrophysical and space emissions.Comment: 11 pages, 12 figures. Accepted by Monthly Notices of the Royal
Astronmical Society in April 200
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The use of theory in research relating to open access: practitioner perspectives
The relationship between theory and practice has long been considered problematic for many applied academic disciplines. In this short paper we report preliminary findings from a twoâyear research project investigating the ways and the extent that theory and practice have interacted in the development of openâaccess (OA) approaches to the publishing and dissemination of research outputs. Based on interviews with practitioners and researchers working on OA related issues, we explore the ways in which theory is (and isn't) of value to practice. We find that while practitioners acknowledge that theory has the potential to improve understanding, bestow credibility on work, and codify existing knowledge about OA, they also perceive it as âmood musicâ to the practical work of OA, lacking explicit links to action
Intrinsic Variability and Field Statistics for the Vela Pulsar: 3. Two-Component Fits and Detailed Assessment of Stochastic Growth Theory
The variability of the Vela pulsar (PSR B0833-45) corresponds to well-defined
field statistics that vary with pulsar phase, ranging from Gaussian intensity
statistics off-pulse to approximately power-law statistics in a transition
region and then lognormal statistics on-pulse, excluding giant micropulses.
These data are analyzed here in terms of two superposed wave populations, using
a new calculation for the amplitude statistics of two vectorially-combined
transverse fields. Detailed analyses show that the approximately power-law and
lognormal distributions observed are fitted well at essentially all on-pulse
phases by Gaussian-lognormal and double-lognormal combinations, respectively.
These good fits, plus the smooth but significant variations in fit parameters
across the source, provide strong evidence that the approximately power-law
statistics observed in the transition region are not intrinsic. Instead, the
data are consistent with normal pulsar emission having lognormal statistics at
all phases. This is consistent with generation in an inhomogeneous source
obeying stochastic growth theory (SGT) and with the emission mechanism being
purely linear (either direct or indirect). A nonlinear mechanism is viable only
if it produces lognormal statistics when suitably ensemble-averaged. Variations
in the SGT fit parameters with phase imply that the radiation is relatively
more variable near the pulse edges than near the center, as found in earlier
work. In contrast, Vela's giant micropulses come from a very restricted phase
range and have power-law statistics with indices () not
inconsistent with nonlinear wave collapse. These results imply that normal
pulses have a different source and generation mechanism than giant micropulses,
as suggested previously on other grounds.Comment: 10 pages and 14 figures. Accepted by Monthly Notices of the Royal
Astronomical Society in April 200
"Talk" about male suicide? Learning from community programmes
Purpose â The purpose of this paper is to examine the contribution of public awareness campaigning in developing community capacity toward preventing male suicide and explores emerging considerations for suicide prevention programme development. Design/methodology/approach â The paper draws on campaign evaluation data, specifically qualitative discussion groups with the general public, to report results concerning campaign processes, and âinterimâ effectiveness in changing public awareness and attitudes, and then discusses how progress is to be lasting and transformational. Findings â The campaign raised the awareness of a substantial proportion of those targeted, and affected attitudes and behaviour of those who were highly aware. The community settings approach was effective in reaching younger men, but there were challenges targeting the public more selectively, and engaging communities in a sustained way. Practical implications â The paper discusses emerging considerations for suicide prevention, focusing on gender and approaches and materials for engaging with the public as âinfluencersâ. There are challenges to target audiences more specifically, provide a clear call to action, and engage the public in a sustained way. Social implications â The paper discusses emerging considerations for suicide prevention, focusing on gender and approaches and materials for engaging with the public as âinfluencersâ. There are challenges to target audiences more specifically, provide a clear call to action, and engage the public in a sustained way. Originality/value â The paper adds fresh evidence of gendered communication processes, including their effects on public awareness, attitudes and engagement. Application of a theory of change model leads to systems level findings for sustaining programme gains
Punishment in society: the improbable persistence of probation and other community sanctions and measures
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