998 research outputs found
Cumbria and the northern Pennines
Carboniferous rocks within the Cumbria and northern Pennines region are bound by
the Maryport–Stublick–Ninety Fathom Fault System, which forms the northern
boundary of the Lake District and Alston blocks (Fig. 12.1). In the Pennines, the
succession occupies the Alston and Askrigg blocks and the intervening Stainmore
Trough, a broadly east-west trending graben. Carboniferous strata also flank the Lake
District High, occurring at outcrop in north Cumbria, Furness and Cartmel (south
Cumbria) and the Vale of Eden, and in the subsurface in west Cumbria. The Askrigg
Block succession is separated from that of the Craven Basin (Chapter 11), to the
south, by the Craven Fault System
Craven Basin and southern Pennines
Carboniferous rocks within this area occupy the region contiguous with the northern
Pennines to the north (Chapter 12) and the Peak District to the south (Chapter 10). All
of the stages of the Carboniferous are present at outcrop, with the exception of
Stephanian strata, which are absent. The oldest Tournaisian strata crop out within the
Craven Basin, and are represented by ramp carbonate rocks (Bowland High Group)
deposited on the Bowland High and adjacent Lancaster Fells and Bowland sub-basins.
These carbonate rocks are overlain by mainly Visean hemipelagic mudstone and
carbonate turbidites (lower part of Craven Group). To the south of the Pendle Fault
System (Fig. 11.1), further platform carbonate rocks are proved in the subsurface
above the Central Lancashire High (Trawden Limestone Group) and the Holme High
and Heywood High (Holme High Limestone Group). These carbonate rocks, which
developed during the Tournaisian to late Visean, are known only from well records
and geophysical information and are not divided into formations. During the Visean,
the platform carbonate rocks pass laterally into more basinal successions in the
Harrogate, Rossendale and Huddersfield sub-basins (Craven Group). The
lithostratigraphical nomenclature for the Tournaisian and Visean strata is that of
Waters et al. (2009), adapted from Riley (1990)
South Wales
Carboniferous rocks in this region occur in a broadly east-west trending syncline, the
core of which includes the South Wales and Pembrokeshire coalfields (Fig. 5.1).
Tournaisian and Visean strata (Avon and Pembroke Limestone groups) represent
deposition on a southward prograding carbonate ramp evolving into a carbonate shelf
(Wright 1987), in a succession which shows similarities to that of the Bristol and
Mendips areas (Chapter 6). The main outcrops, in south Pembrokeshire, Gower and
the Vale of Glamorgan, occur along the southern periphery of the coalfields and are
commonly affected by Variscan thrusting and folding. Thinner successions occur
along what is termed the East Crop and North Crop of the South Wales Coalfield,
where much of the Visean succession is absent due to sub-Namurian and intra-Visean
unconformities. Namurian fluvio-deltaic deposits (Marros Group) flank the South
Wales and Pembrokeshire coalfields. Much of the lower and middle Namurian
succession is absent across the region, except in the west of the South Wales Coalfield
where only small parts are absent beneath an intra-Namurian unconformity.
Westphalian fluvio-lacustrine deposits (South Wales Coal Measures Group) form the
South Wales and Pembrokeshire coalfields, located to the east and west of
Carmarthen Bay, respectively. Westphalian to Stephanian Pennant alluvial facies
(Warwickshire Group) occur in the core of the South Wales Coalfield syncline.
Deposition of the South Wales Coal Measures and Warwickshire groups was
probably laterally contiguous with those in the Bristol and Somerset coalfields
(Chapter 6), but the Usk-Cowbridge High controlled and restricted sedimentation for
much of the Carboniferous, with pre-Namurian uplift and erosion removing the
Tournaisian and Visean succession. Later uplift is also believed to have caused
attenuation of the Warwickshire Group in the east of the South Wales Coalfield. The
lithostratigraphical nomenclature for the region is that of Waters et al. (2007; 2009)
Design, characterisation and properties of Mo-Ti-Fe alloys reinforced by ordered intermetallic precipitates
Reinforcement of solid solution matrices with ordered intermetallic precipitates is known to be an effective strategy for obtaining high strength, damage tolerant alloys and has been central to the success of nickel based superalloys. This strategy has also been exploited in a number of bcc-based systems, for example in maraging steels where ferrite is strengthened by L21 (Heusler) and/or B2 structured intermetallic precipitates. However, only limited studies have explored the possibility of extending this approach to bcc alloys based on refractory metals and titanium.
Recent research has shown that titanium-iron alloys comprising eutectic A2 Ti and B2 TiFe phases may be produced with strengths of over 2.5 GPa, alongside elongations to failures of ~15%. These impressive properties are thought to be a result of a fine microstructural length scale and a high lattice misfit between the phases. Here, we report on the phase equilibria in the Mo-Ti-Fe ternary system. In this system, an extensive two-phase field was identified between B2 TiFe intermetallic phase and the A2 (Ti, Mo) solid solution, that extended to Mo rich compositions. Knowledge of how this phase equilibrium varies with temperature enabled the design of alloys that could be homogenised in the single-phase solid solution and subsequently reinforced by solid state precipitates following a lower temperature heat treatment. The microstructure obtained was finer than has been produced through an invariant reaction and an initial assessment of their mechanical properties revealed substantial strength. The prospects for modifying these alloys to enable their use at higher temperatures will be discussed.
This work was supported through the Rolls-Royce/EPSRC Strategic Partnership under EP/H022309/1 and EP/H500375/1, as well as the DARE project under EP/L025213/1
Effectiveness of Community Forest Management at reducing deforestation in Madagascar
AbstractCommunity Forest Management (CFM) is a widespread conservation approach in the tropics. It is also promoted as a means by which payment for ecosystem services schemes can be implemented. However, evidence on its performance is weak. We investigated the effectiveness of CFM at reducing deforestation from 2000 to 2010 in Madagascar. To control for factors confounding impact estimates, we used statistical matching. We also contrasted the effects of CFM by whether commercial use of forest resources is allowed or not. We cannot detect an effect, on average, of CFM compared to no CFM, even when we restricted the sample to only where information suggests effective CFM implementation on the ground. Likewise, we cannot detect an effect of CFM where commercial use of natural resources is allowed. However, we can detect a reduction in deforestation in CFM that does not permit commercial uses, compared to no CFM or CFM allowing commercial uses. Our findings suggest that CFM and commercial use of forest resources are not guarantees of forest conservation and that differentiating among types of CFM is important
Renormalon Singularities of the QCD Vacuum Polarization Function to Leading Order in
We explicitly determine the residues and orders of all the ultra-violet (UV)
and infra-red (IR) renormalon poles in the Borel plane for the QCD vacuum
polarization function (Adler D-function), to leading order in an expansion in
the number of quark flavours, . The singularity structure is precisely
as anticipated on general grounds. In particular, the leading IR renormalon is
absent, in agreement with operator product expansion ideas. There is a curious
and unexplained symmetry between the third and higher UV and IR renormalon
residues. We are able to sum up separately UV and IR contributions to obtain
closed form results involving -functions. We argue that the leading UV
renormalon should have a more complicated structure than conventionally
assumed. The disappearance of IR renormalons in flavour-saturated SU() QCD
is shown to occur for or 9.Comment: 22 pages of LaTeX, revisions to this paper are mainly typographica
Use of clinical vignette questionnaires to investigate the variation in management of keratoconjunctivitis sicca and acute glaucoma in dogs
There is little peer-reviewed research assessing therapeutic effectiveness in canine eye disease. Current treatments used in first opinion and ophthalmology referral practices are also somewhat poorly documented. The aim of this study was to investigate the current management of canine keratoconjunctivitis sicca (KCS) and acute primary angle-closure glaucoma (PACG) by veterinary surgeons. Questionnaires using clinical vignettes were administered to a cross section of general practitioners (‘GPs’) and veterinarians engaged in or training for postgraduate ophthalmology practice (’PGs’). Similar treatment recommendations for KCS (topical cyclosporine, lubricant, antibiotic) were given by both groups of veterinarians with the single exception of increased topical antibiotic use by GPs. Treatment of acute glaucoma diverged between groups: PGs were much more likely to recommend topical prostaglandin analogues (PGAs) and a wider array of both topical and systemic treatments were recommended by both groups. Systemic ocular hypotensive agents were suggested infrequently. Our results suggest that treatments may vary substantially in ocular conditions, particularly in conditions for which neither guidelines nor high quality evidence exists. This study highlights the need for novel strategies to address evidence gaps in veterinary medicine, as well as for better evaluation and dissemination of current treatment experience
HadISDH: an updateable land surface specific humidity product for climate monitoring
HadISDH is a near-global land surface specific humidity monitoring product providing monthly means from 1973 onwards over large-scale grids. Presented herein to 2012, annual updates are anticipated. HadISDH is an update to the land component of HadCRUH, utilising the global high-resolution land surface station product HadISD as a basis. HadISD, in turn, uses an updated version of NOAA's Integrated Surface Database. Intensive automated quality control has been undertaken at the individual observation level, as part of HadISD processing. The data have been subsequently run through the pairwise homogenisation algorithm developed for NCDC's US Historical Climatology Network monthly temperature product. For the first time, uncertainty estimates are provided at the grid-box spatial scale and monthly timescale.
HadISDH is in good agreement with existing land surface humidity products in periods of overlap, and with both land air and sea surface temperature estimates. Widespread moistening is shown over the 1973–2012 period. The largest moistening signals are over the tropics with drying over the subtropics, supporting other evidence of an intensified hydrological cycle over recent years. Moistening is detectable with high (95%) confidence over large-scale averages for the globe, Northern Hemisphere and tropics, with trends of 0.089 (0.080 to 0.098) g kg−1 per decade, 0.086 (0.075 to 0.097) g kg−1 per decade and 0.133 (0.119 to 0.148) g kg−1 per decade, respectively. These changes are outside the uncertainty range for the large-scale average which is dominated by the spatial coverage component; station and grid-box sampling uncertainty is essentially negligible on large scales. A very small moistening (0.013 (−0.005 to 0.031) g kg−1 per decade) is found in the Southern Hemisphere, but it is not significantly different from zero and uncertainty is large. When globally averaged, 1998 is the moistest year since monitoring began in 1973, closely followed by 2010, two strong El Niño years. The period in between is relatively flat, concurring with previous findings of decreasing relative humidity over land
Polyhedral Analysis using Parametric Objectives
The abstract domain of polyhedra lies at the heart of many program analysis techniques. However, its operations can be expensive, precluding their application to polyhedra that involve many variables. This paper describes a new approach to computing polyhedral domain operations. The core of this approach is an algorithm to calculate variable elimination (projection) based on parametric linear programming. The algorithm enumerates only non-redundant inequalities of the projection space, hence permits anytime approximation of the output
Alternative parameterisations for predictive control: how and why?
This paper looks at the efficiency of the parameterisation of the degrees of freedom within an optimal predictive control algorithm. It is shown that the conventional approach of directly determining each individual future control move is not efficient in general, and can give poor feasibility when the number of degrees of freedom are limited. Two systematic alternatives are explored and both shown to be far more efficient in general
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