890 research outputs found
Developments in the South Staffordshire iron and steel industry, 1850-1913, in the light of home and foreign competition
When Ebenezer Parkes was discussing the question of foreign competition as it affected the local iron and steel industry at the turn of the century, he stressed that it was a 'many sided thing'. Besides, if South Staffordshire was to reassert itself, then improvements would have to come about in a number of areas - in education, use of labour-saving machinery, practices in the blast furnace and rolling-mill departments, labour relations, canal and rail transport, structure of industry, state support and Colonial trade. This thesis is an attempt to look at the various 'sides' of the South Staffordshire iron and steel industry as it faced up to increasing competition both from other United Kingdom districts and from abroad. The importance of physical factors is considered in conjunction with human ones. Clearly, South Staffordshire could do nothing to prevent the growth of new centres of iron and steel production; furthermore, other older centres of production, notably South Wales and Scotland, fared better in the second half of the nineteenth century because of their tidal locations. Iron ores from Spain or steel 'semis' from the United States or the European Continent tended to emphasise the shift away from a land-locked centre of production. Abroad, tremendous growth was experienced by the iron and steel industries of the United States and Germany, a development which made all the apparent disadvantages of South Staffordshire appear that much more significant. Of these disadvantages, South Staffordshire's almost total dependence on outside supplies of metallurgical coke ranks very high. So, too, do the numerous shortcomings of the transport facilities of the area. On the human side, the failure of the local ironmasters to take full advantage of the proximity of East Midland iron ore supplies was crucial. Their reliance upon outside supplies of iron are, which remained largely out of their control, put them in sharp contrast with producers on the Continent or in the United states. To add to the difficulties being experienced by the local industry, Birmingham and the Black Country proved a very attractive market for foreign producers. The so-called 'dumping' policies of the Americans and Continentals are pursued at some length in the last chapter. Despite the many changes which took place in the district, South Staffordshire remained a very important part of the United Kingdom iron and steel industry. The fortunes of Round Oak, and especially those of Sir Alfred Hickman's Spring Vale Works, illustrate the fact that overall the situation in South Staffordshire was never a totally hopeless one
Next-to-next-to-leading-order epsilon expansion for a Fermi gas at infinite scattering length
We extend previous work on applying the epsilon-expansion to universal
properties of a cold, dilute Fermi gas in the unitary regime of infinite
scattering length. We compute the ratio xi = mu/epsilon_F of chemical potential
to ideal gas Fermi energy to next-to-next-to-leading order (NNLO) in
epsilon=4-d, where d is the number of spatial dimensions. We also explore the
nature of corrections from the order after NNLO.Comment: 28 pages, 14 figure
Obtaining Bounds on The Sum of Divergent Series in Physics
Under certain circumstances, some of which are made explicit here, one can
deduce bounds on the full sum of a perturbation series of a physical quantity
by using a variational Borel map on the partial series. The method is
illustrated by applying it to various examples, physical and mathematical.Comment: 33 pages, Journal Versio
New approach to Borel summation of divergent series and critical exponent estimates for an N-vector cubic model in three dimensions from five-loop \epsilon expansions
A new approach to summation of divergent field-theoretical series is
suggested. It is based on the Borel transformation combined with a conformal
mapping and does not imply the exact asymptotic parameters to be known. The
method is tested on functions expanded in their asymptotic power series. It is
applied to estimating the critical exponent values for an N-vector field model,
describing magnetic and structural phase transitions in cubic and tetragonal
crystals, from five-loop \epsilon expansions.Comment: 9 pages, LaTeX, 3 PostScript figure
Critical Behavior of an Ising System on the Sierpinski Carpet: A Short-Time Dynamics Study
The short-time dynamic evolution of an Ising model embedded in an infinitely
ramified fractal structure with noninteger Hausdorff dimension was studied
using Monte Carlo simulations. Completely ordered and disordered spin
configurations were used as initial states for the dynamic simulations. In both
cases, the evolution of the physical observables follows a power-law behavior.
Based on this fact, the complete set of critical exponents characteristic of a
second-order phase transition was evaluated. Also, the dynamic exponent of the critical initial increase in magnetization, as well as the critical
temperature, were computed. The exponent exhibits a weak dependence
on the initial (small) magnetization. On the other hand, the dynamic exponent
shows a systematic decrease when the segmentation step is increased, i.e.,
when the system size becomes larger. Our results suggest that the effective
noninteger dimension for the second-order phase transition is noticeably
smaller than the Hausdorff dimension. Even when the behavior of the
magnetization (in the case of the ordered initial state) and the
autocorrelation (in the case of the disordered initial state) with time are
very well fitted by power laws, the precision of our simulations allows us to
detect the presence of a soft oscillation of the same type in both magnitudes
that we attribute to the topological details of the generating cell at any
scale.Comment: 10 figures, 4 tables and 14 page
Critical Exponents of the pure and random-field Ising models
We show that current estimates of the critical exponents of the
three-dimensional random-field Ising model are in agreement with the exponents
of the pure Ising system in dimension 3 - theta where theta is the exponent
that governs the hyperscaling violation in the random case.Comment: 9 pages, 4 encapsulated Postscript figures, REVTeX 3.
Surface critical behavior in fixed dimensions : Nonanalyticity of critical surface enhancement and massive field theory approach
The critical behavior of semi-infinite systems in fixed dimensions is
investigated theoretically. The appropriate extension of Parisi's massive field
theory approach is presented.Two-loop calculations and subsequent Pad\'e-Borel
analyses of surface critical exponents of the special and ordinary phase
transitions yield estimates in reasonable agreement with recent Monte Carlo
results. This includes the crossover exponent , for which we obtain
the values and , considerably
lower than the previous -expansion estimates.Comment: Latex with Revtex-Stylefiles, 4 page
On the equivalence of the self-dual and Maxwell-Chern-Simons models coupled to Fermions
We study the exact equivalence between the self-dual model minimally coupled
with a Dirac field and the Maxwell-Chern-Simons model with non-minimal magnetic
coupling to fermions. We show that the fermion sectors of the models are
equivalent only if a Thirring like interaction is included. Using functional
methods we verify that, up to renormalizations, the equivalence persists at the
quantum level.Comment: 8 pages, revte
Colorimetric detection of caspase 3 activity and reactive oxygen derivatives: Potential early indicators of thermal stress in corals
© 2016 Mickael Ros et al. There is an urgent need to develop and implement rapid assessments of coral health to allow effective adaptive management in response to coastal development and global change. There is now increasing evidence that activation of caspase-dependent apoptosis plays a key role during coral bleaching and subsequent mortality. In this study, a "clinical" approach was used to assess coral health by measuring the activity of caspase 3 using a commercial kit. This method was first applied while inducing thermal bleaching in two coral species, Acropora millepora and Pocillopora damicornis. The latter species was then chosen to undergo further studies combining the detection of oxidative stress-related compounds (catalase activity and glutathione concentrations) as well as caspase activity during both stress and recovery phases. Zooxanthellae photosystem II (PSII) efficiency and cell density were measured in parallel to assess symbiont health. Our results demonstrate that the increased caspase 3 activity in the coral host could be detected before observing any significant decrease in the photochemical efficiency of PSII in the algal symbionts and/or their expulsion from the host. This study highlights the potential of host caspase 3 and reactive oxygen species scavenging activities as early indicators of stress in individual coral colonies
Tests and foreseen developments of fibered-OSLD gamma heating measurements in low-power reactors
International audienceIn this paper are presented test measurements of a fibered-OSLD system performed during a dedicated experimental phase in EOLE zero-power reactor. The measurement setup consists of an OSLD crystal connected onto the extremity of an optical fiber and a laser stimulation system, manufactured by the CEA/LIST in Saclay. The OSL sensor is remotely stimulated via an optical fiber using a diode-pumped solid-state laser. The OSL light is collected and guided back along the same fiber to a photomultiplier tube. Results obtained using this system are compared to usual gamma heating measurement protocol using OSLD pellets. The presence of induced radio-luminescence in the OSLD during the irradiation was also observed and could be used to monitor the gamma flux.The feasibility of remote measurements is achieved, whereas further developments could be conducted to improve this technique since the readout procedure still requires to withdraw the OSLD off the gamma flux (hence from the core) on account of the dose rate (around a few Gy.h-1), and the readout time remains quite long for on-line applications. Several improvements are foreseen, and will be tested in the forthcoming years
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