1,098 research outputs found
Bridge distress caused by approach embankment settlement
Surtees Bridge, which carries the A66(T) over the River
Tees near Thornaby-on-Tees in the UK, has been
showing signs of distress that predate its opening in
1981. Subsequent investigations have shown that the
bridge distress is related to unexpectedly large
settlement of the eastern approach embankment.
Recent ground investigations prompted by a proposed
widening of the river crossing have produced many new
data on the alluvial deposits underlying the site, and
explain why embankment settlement was so much larger
than originally anticipated. Comparison of the
geotechnical parameters obtained from the original and
more recent ground investigations suggests that the
original investigation significantly underestimated the
thickness of an alluvial clay layer underlying the site, and
that its coefficient of consolidation was overestimated.
Settlement analyses using geotechnical data from the
original ground investigations predict moderate
embankment settlements occurring principally during
construction. Settlement analyses based on all the
available data predict far larger embankment
settlements occurring over extended time periods. The
latter analyses predict an embankment settlement
similar to that observed and of sufficient magnitude to
cause the observed lateral displacement of the bridge
due to lateral loading of its piled foundation
On Kedlaya type inequalities for weighted means
In 2016 we proved that for every symmetric, repetition invariant and Jensen
concave mean the Kedlaya-type inequality holds for an
arbitrary ( stands for the arithmetic mean). We are going
to prove the weighted counterpart of this inequality. More precisely, if
is a vector with corresponding (non-normalized) weights
and denotes the weighted mean then, under
analogous conditions on , the inequality holds for every and such that the sequence
is decreasing.Comment: J. Inequal. Appl. (2018
Groundwater “fast paths” in the Snake River Plain aquifer: Radiogenic isotope ratios as natural groundwater tracers
Preferential flow paths are expected in many groundwater systems and must be located because they can greatly affect contaminant transport. The fundamental characteristics of radiogenic isotope ratios in chemically evolving waters make them highly effective as preferential flow path indicators. These ratios tend to be more easily interpreted than solute-concentration data because their response to water-rock interaction is less complex. We demonstrate this approach with groundwater {sup 87}Sr/{sup 86}Sr ratios in the Snake River Plain aquifer within and near the Idaho National Engineering and Environmental Laboratory. These data reveal slow-flow zones as lower {sup 87}Sr/{sup 86}Sr areas created by prolonged interaction with the host basalts and a relatively fast flowing zone as a high {sup 87}Sr/{sup 86}Sr area
Geophysical studies with laser-beam detectors of gravitational waves
The existing high technology laser-beam detectors of gravitational waves may
find very useful applications in an unexpected area - geophysics. To make
possible the detection of weak gravitational waves in the region of high
frequencies of astrophysical interest, ~ 30 - 10^3 Hz, control systems of laser
interferometers must permanently monitor, record and compensate much larger
external interventions that take place in the region of low frequencies of
geophysical interest, ~ 10^{-5} - 3 X 10^{-3} Hz. Such phenomena as tidal
perturbations of land and gravity, normal mode oscillations of Earth,
oscillations of the inner core of Earth, etc. will inevitably affect the
performance of the interferometers and, therefore, the information about them
will be stored in the data of control systems. We specifically identify the
low-frequency information contained in distances between the interferometer
mirrors (deformation of Earth) and angles between the mirrors' suspensions
(deviations of local gravity vectors and plumb lines). We show that the access
to the angular information may require some modest amendments to the optical
scheme of the interferometers, and we suggest the ways of doing that. The
detailed evaluation of environmental and instrumental noises indicates that
they will not prevent, even if only marginally, the detection of interesting
geophysical phenomena. Gravitational-wave instruments seem to be capable of
reaching, as a by-product of their continuous operation, very ambitious
geophysical goals, such as observation of the Earth's inner core oscillations.Comment: 29 pages including 8 figures, modifications and clarifications in
response to referees' comments, to be published in Class. Quant. Gra
From Deficit to Strength-Based Aboriginal Health Research—Moving toward Flourishing
Aboriginal Australians have a fundamental human right to opportunities that lead to healthy and flourishing lives. While the impact of trauma on Aboriginal Australians is well-documented, a pervasive deficit narrative that focuses on problems and pathology persists in research and policy discourse. This narrative risks further exacerbating Aboriginal disadvantage through a focus on 'fixing what is wrong' with Aboriginal Australians and the internalising of these narratives by Aboriginal Australians. While a growing body of research adopts strength-based models, limited research has sought to explore Aboriginal flourishing. This conceptual paper seeks to contribute to a burgeoning paradigm shift in Aboriginal research, seeking to understand what can be learned from Aboriginal people who flourish, how we best determine this, and in what contexts this can be impactful. Within, we argue the case for a new approach to exploring Aboriginal wellbeing that integrates salutogenic, positive psychology concepts with complex systems theory to understand and promote Aboriginal wellbeing and flourishing. While deeper work may be required to establish the parameters of a strength-based, culturally aligned Aboriginal conceptualisation of positive psychology, we suggest the integration of Aboriginal and Western methodologies offers a unique and potent means of shifting the dial on seemingly intractable problems.Jonathan Bullen, Trish Hill-Wall, Kate Anderson, Alex Brown, Clint Bracknell, Elizabeth A. Newnham, Gail Garvey, and Lea Water
UK Large-scale Wind Power Programme from 1970 to 1990: the Carmarthen Bay experiments and the Musgrove Vertical-Axis Turbines
This article describes the development of the Musgrove Vertical Axis Wind Turbine (VAWT)
concept, the UK ‘Carmarthen Bay’ wind turbine test programme, and UK government’s wind
power programme to 1990. One of the most significant developments in the story of British
wind power occurred during the 1970s, 1980s, and 1990s, with the development of the
Musgrove vertical axis wind turbine and its inclusion within the UK Government’s wind
turbine test programme. Evolving from a supervisor’s idea for an undergraduate project at
Reading University, the Musgrove VAWT was once seen as an able competitor to the
horizontal axis wind systems that were also being encouraged at the time by both the UK
government and the Central Electricity Generating Board, the then nationalised electricity
utility for England and Wales. During the 1980s and 1990s the most developed Musgrove
VAWT system, along with three other commercial turbine designs was tested at
Carmarthen Bay, South Wales as part of a national wind power test programme. From these
developmental tests, operational data was collected and lessons learnt, which were
incorporated into subsequent wind power operations.http://dx.doi.org/10.1260/03095240677860621
Biogenesis of the inner membrane complex is dependent on vesicular transport by the alveolate specific GTPase Rab11B
Apicomplexan parasites belong to a recently recognised group of protozoa referred to as Alveolata. These protists contain membranous sacs (alveoli) beneath the plasma membrane, termed the Inner Membrane Complex (IMC) in the case of Apicomplexa. During parasite replication the IMC is formed de novo within the mother cell in a process described as internal budding. We hypothesized that an alveolate specific factor is involved in the specific transport of vesicles from the Golgi to the IMC and identified the small GTPase Rab11B as an alveolate specific Rab-GTPase that localises to the growing end of the IMC during replication of Toxoplasma gondii. Conditional interference with Rab11B function leads to a profound defect in IMC biogenesis, indicating that Rab11B is required for the transport of Golgi derived vesicles to the nascent IMC of the daughter cell. Curiously, a block in IMC biogenesis did not affect formation of sub-pellicular microtubules, indicating that IMC biogenesis and formation of sub-pellicular microtubules is not mechanistically linked. We propose a model where Rab11B specifically transports vesicles derived from the Golgi to the immature IMC of the growing daughter parasites
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