1,752 research outputs found
Towards the âultimate earthquake-proofâ building: Development of an integrated low-damage system
The 2010â2011 Canterbury earthquake sequence has highlighted the
severe mismatch between societal expectations over the reality of seismic performance
of modern buildings. A paradigm shift in performance-based design criteria
and objectives towards damage-control or low-damage design philosophy and
technologies is urgently required. The increased awareness by the general public,
tenants, building owners, territorial authorities as well as (re)insurers, of the severe
socio-economic impacts of moderate-strong earthquakes in terms of damage/dollars/
downtime, has indeed stimulated and facilitated the wider acceptance and
implementation of cost-efficient damage-control (or low-damage) technologies.
The âbarâ has been raised significantly with the request to fast-track the development
of what the wider general public would hope, and somehow expect, to live
in, i.e. an âearthquake-proofâ building system, capable of sustaining the shaking of
a severe earthquake basically unscathed.
The paper provides an overview of recent advances through extensive research,
carried out at the University of Canterbury in the past decade towards the development
of a low-damage building system as a whole, within an integrated
performance-based framework, including the skeleton of the superstructure, the
non-structural components and the interaction with the soil/foundation system.
Examples of real on site-applications of such technology in New Zealand, using
concrete, timber (engineered wood), steel or a combination of these materials, and
featuring some of the latest innovative technical solutions developed in the laboratory
are presented as examples of successful transfer of performance-based seismic
design approach and advanced technology from theory to practice
Joint inversion of surface waves and teleseismic body waves across the Tibetan collision zone: The fate of subducted Indian lithosphere
We carry out a joint inversion of surface wave dispersion curves and teleseismic shear wave arrival times across the Tibetan collision zone, from just south of the Himalaya to the Qaidam Basin at the northeastern margin of the plateau, and from the surface to 600 km depth. The surface wave data consist of Rayleigh-wave group dispersion curves, mainly in the period range from 10 to 70 s, with a maximum of 2877 sourceâreceiver pairs. The body wave data consist of more than 8000 S-wave arrival times recorded from 356 telesesmic events. The tomographic images show a âwedgeâ of fast seismic velocities beneath central Tibet that starts underneath the Himalaya and reaches as far as the BangongâNujiang Suture (BNS). In our preferred interpretation, in central Tibet the Indian lithosphere underthrusts the plateau to approximately the BNS, and then subducts steeply. Further east, Indian lithosphere appears to be subducting at an angle of âŒ45°. We see fast seismic velocities under much of the plateau, as far as the BNS in central Tibet, and as far as the Xiangshuihe-Xiaojiang Fault in the east. At 150 km depth, the fast region is broken by an area âŒ300 km wide that stretches from the northern edge of central Tibet southeastwards as far as the Himalaya. We suggest that this gap, which has been observed previously by other investigators, represents the northernmost edge of the Indian lithosphere, and is a consequence of the steepening of the subduction zone from central to eastern Tibet. This also implies that the fast velocities in the northeast have a different origin, and are likely to be caused by lithospheric thickening or small-scale subduction of Asian lithosphere. Slow velocities observed to the south of the Qaidam suggest that the basin is not subducting. Finally, we interpret fast velocities below 400 km as subducted material from an earlier stage of the collision that has stalled in the transition zone. Its position to the south of the present subduction is likely to be due to the relative motion of India to the northeast.Our study has included data from GSN (including IC, IU and II), China Digital Seismograph Network, GEOSCOPE, IRIS-IDA, Pacific-21, Kyrgyz Digital Network, Kyrgyz Seismic Telemetry Network and IRIS-USGS permanent seismic networks and the MANAS, Tien Shan Continental Dynamics, Tibetan Plateau Broadband Experiment, INDEPTH II, INDEPTH III, INDEPTH IV/ASCENT, HIMNT, Bhutan, Nanga Parbat Pakistan and GHENGIS PASSCAL temporary seismic deployments. We thank IIEES and LGIT for seismic data from Iran and also SEISUK for provision and assistance with instruments operated in northeast India. CN was supported by a Natural Environment Research Council studentship (grant NE/H52449X/1), with CASE funding from AWE Blacknest. We thank Nick Rawlinson and an anonymous reviewer for their constructive and helpful reviews. Figures were prepared with Generic Mapping Tools (GMT) software (Wessel & Smith 1998).This is the version of record, which can also be found on the publisher's website at: http://gji.oxfordjournals.org/content/198/3/1526.full © The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Societ
Slow equivariant lump dynamics on the two sphere
The low-energy, rotationally equivariant dynamics of n CP^1 lumps on S^2 is
studied within the approximation of geodesic motion in the moduli space of
static solutions. The volume and curvature properties of this moduli space are
computed. By lifting the geodesic flow to the completion of an n-fold cover of
the moduli space, a good understanding of nearly singular lump dynamics within
this approximation is obtained.Comment: 12 pages, 3 figure
Effects of two doses of glucose and a caffeine-glucose combination on cognitive performance and mood during multi-tasking
Background: This study assessed the effects of two doses of glucose and a caffeineâglucose combination on mood and performance of an
ecologically valid, computerised multi-tasking platform.
Materials and methods: Following a double-blind, placebo-controlled, randomised, parallel-groups design, 150 healthy adults (mean age
34.78 years) consumed drinks containing placebo, 25 g glucose, 60 g glucose or 60 g glucose with 40 mg caffeine. They completed a multitasking
framework at baseline and then 30 min following drink consumption with mood assessments immediately before and after the multitasking
framework. Blood glucose and salivary caffeine were co-monitored.
Results: The caffeineâglucose group had significantly better total multi-tasking scores than the placebo or 60 g glucose groups and were
significantly faster at mental arithmetic tasks than either glucose drink group. There were no significant treatment effects on mood. Caffeine
and glucose levels confirmed compliance with overnight abstinence/fasting, respectively, and followed the predicted post-drink patterns.
Conclusion: These data suggest that co-administration of glucose and caffeine allows greater allocation of attentional resources than
placebo or glucose alone. At present, we cannot rule out the possibility that the effects are due to caffeine alone Future studies should aim
at disentangling caffeine and glucose effect
Case study:shipping trend estimation and prediction via multiscale variance stabilisation
<p>Shipping and shipping services are a key industry of great importance to the economy of Cyprus and the wider European Union. Assessment, management and future steering of the industry, and its associated economy, is carried out by a range of organisations and is of direct interest to a number of stakeholders. This article presents an analysis of shipping credit flow data: an important and archetypal series whose analysis is hampered by rapid changes of variance. Our analysis uses the recently developed data-driven HaarâFisz transformation that enables accurate trend estimation and successful prediction in these kinds of situation. Our trend estimation is augmented by bootstrap confidence bands, new in this context. The good performance of the data-driven HaarâFisz transform contrasts with the poor performance exhibited by popular and established variance stabilisation alternatives: the BoxâCox, logarithm and square root transformations.</p
Out-of-plane behavior of one-way spanning unreinforced masonry walls
An analytical model is developed to describe the out-of-plane response of one-way spanning unreinforced masonry (URM) walls by investigating the effects of various parameters. Horizontal crack height, masonry compressive strength, and diaphragm support stiffness properties are assumed as variables, and sensitivity analyses are performed to study the influence of these parameters on the cracked wall characteristic behavior. The parametric studies show that crack height significantly influences wall stability by affecting both the instability displacement and the wall lateral resistance. The reduction in cracked wall lateral resistance and in the instability displacement caused by finite masonry compressive strength is shown to be significantly amplified by the applied overburden. A study using the typical configuration of flexible diaphragms and URM walls indicates that the wall top support flexibility does not significantly influence cracked wall out-of-plane response. An existing simplified wall behavioral model is improved, and a procedure is proposed for calculation of the wall out-of-plane response envelope.Hossein Derakhshan; Michael C. Griffith; and Jason M. Ingha
Characterization of the Crab Pulsar's Timing Noise
We present a power spectral analysis of the Crab pulsar's timing noise,
mainly using radio measurements from Jodrell Bank taken over the period
1982-1989. The power spectral analysis is complicated by nonuniform data
sampling and the presence of a steep red power spectrum that can distort power
spectra measurement by causing severe power ``leakage''. We develop a simple
windowing method for computing red noise power spectra of uniformly sampled
data sets and test it on Monte Carlo generated sample realizations of red
power-law noise. We generalize time-domain methods of generating power-law red
noise with even integer spectral indices to the case of noninteger spectral
indices. The Jodrell Bank pulse phase residuals are dense and smooth enough
that an interpolation onto a uniform time series is possible. A windowed power
spectrum is computed revealing a periodic or nearly periodic component with a
period of about 568 days and a 1/f^3 power-law noise component with a noise
strength of 1.24 +/- 0.067 10^{-16} cycles^2/sec^2 over the analysis frequency
range 0.003 - 0.1 cycles/day. This result deviates from past analyses which
characterized the pulse phase timing residuals as either 1/f^4 power-law noise
or a quasiperiodic process. The analysis was checked using the Deeter
polynomial method of power spectrum estimation that was developed for the case
of nonuniform sampling, but has lower spectral resolution. The timing noise is
consistent with a torque noise spectrum rising with analysis frequency as f
implying blue torque noise, a result not predicted by current models of pulsar
timing noise. If the periodic or nearly periodic component is due to a binary
companion, we find a companion mass > 3.2 Earth masses.Comment: 53 pages, 9 figures, submitted to MNRAS, abstract condense
School-based curriculum development in Scotland: Curriculum policy and enactment
Recent worldwide trends in curriculum policy have re-emphasised the role of teachers in school-based curriculum development. Scotland’s Curriculum for Excellence is typical of these trends, stressing that teachers are agents of change. This paper draws upon empirical data to explore school-based curriculum development in response to Curriculum for Excellence. We focus on two case studies – secondary schools within a single Scottish local education authority. In the paper we argue that the nature and extent of innovation in schools is dependent upon teachers being able to make sense of often complex and confusing curriculum policy, including the articulation of a clear vision about what such policy means for education within each school
Spectral Analysis of Guanine and Cytosine Fluctuations of Mouse Genomic DNA
We study global fluctuations of the guanine and cytosine base content (GC%)
in mouse genomic DNA using spectral analyses. Power spectra S(f) of GC%
fluctuations in all nineteen autosomal and two sex chromosomes are observed to
have the universal functional form S(f) \sim 1/f^alpha (alpha \approx 1) over
several orders of magnitude in the frequency range 10^-7< f < 10^-5 cycle/base,
corresponding to long-ranging GC% correlations at distances between 100 kb and
10 Mb. S(f) for higher frequencies (f > 10^-5 cycle/base) shows a flattened
power-law function with alpha < 1 across all twenty-one chromosomes. The
substitution of about 38% interspersed repeats does not affect the functional
form of S(f), indicating that these are not predominantly responsible for the
long-ranged multi-scale GC% fluctuations in mammalian genomes. Several
biological implications of the large-scale GC% fluctuation are discussed,
including neutral evolutionary history by DNA duplication, chromosomal bands,
spatial distribution of transcription units (genes), replication timing, and
recombination hot spots.Comment: 15 pages (figures included), 2 figure
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