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Novel Sensor Design Using Photonic Crystal Fibres for Monitoring the Onset of Corrosion in Reinforced Concrete Structures
In this paper, a novel sensing technique has been designed and investigated for the direct, in-situ detection of steel corrosion distributed in reinforced concrete structures. At present, structural health monitoring (SHM) in reinforced concrete structures is generally focused on monitoring the corrosion risk of the reinforcing steel. It is of significant importance, however, to inform industry of both the onset of corrosion and the corrosion rate as these are key contributors to structural degradation and thus evaluating the service life of the structures. This paper aims to address the above challenges by describing a novel corrosion sensor design using birefringent photonic crystal fibres (PCFs). The technique exploits fully both the birefringence of the fibres for force/pressure measurement and their very low temperature sensitivity to detect the onset of corrosion. This new type of sensor not only determines the onset of corrosion but also allows for better monitoring along the length of a reinforcement bar
Fermionic Determinant of the Massive Schwinger Model
A representation for the fermionic determinant of the massive Schwinger
model, or , is obtained that makes a clean separation between the
Schwinger model and its massive counterpart. From this it is shown that the
index theorem for follows from gauge invariance, that the Schwinger
model's contribution to the determinant is canceled in the weak field limit,
and that the determinant vanishes when the field strength is sufficiently
strong to form a zero-energy bound state
A unified BFKL and GLAP description of data
We argue that the use of the universal unintegrated gluon distribution and
the (or high energy) factorization theorem provides the natural framework
for describing observables at small x. We introduce a coupled pair of evolution
equations for the unintegrated gluon distribution and the sea quark
distribution which incorporate both the resummed leading BFKL
contributions and the resummed leading GLAP contributions. We solve
these unified equations in the perturbative QCD domain using simple parametic
forms of the nonperturbative part of the integrated distributions. With only
two (physically motivated) input parameters we find that this
factorization approach gives an excellent description of the measurements of
at HERA. In this way the unified evolution equations allow us to
determine the gluon and sea quark distributions and, moreover, to see the x
domain where the resummed effects become significant. We use
factorization to predict the longitudinal structure function and
the charm component of .Comment: 25 pages, LaTeX, 9 figure
Chiral non-linear sigma-models as models for topological superconductivity
We study the mechanism of topological superconductivity in a hierarchical
chain of chiral non-linear sigma-models (models of current algebra) in one,
two, and three spatial dimensions. The models have roots in the 1D
Peierls-Frohlich model and illustrate how the 1D Frohlich's ideal conductivity
extends to a genuine superconductivity in dimensions higher than one. The
mechanism is based on the fact that a point-like topological soliton carries an
electric charge. We discuss a flux quantization mechanism and show that it is
essentially a generalization of the persistent current phenomenon, known in
quantum wires. We also discuss why the superconducting state is stable in the
presence of a weak disorder.Comment: 5 pages, revtex, no figure
Inhomogeneous Condensates in Planar QED
We study the formation of vacuum condensates in dimensional QED in the
presence of inhomogeneous background magnetic fields. For a large class of
magnetic fields, the condensate is shown to be proportional to the
inhomogeneous magnetic field, in the large flux limit. This may be viewed as a
{\it local} form of the {\it integrated} degeneracy-flux relation of Aharonov
and Casher.Comment: 13 pp, LaTeX, no figures; to appear in Phys. Rev.
Author Correction: Multifunctional light beam control device by stimuli-responsive liquid crystal micro-grating structures
Correction to: Scientific Reports https://doi.org/10.1038/s41598-020-70783-8, published online 14 August 2020
This Article contains a typographical error in the Acknowledgements section.
“the Ministerio de EconomĂa y Competitividad of Spain (TEC2013-47342-C2-2-R)”
should read:
"the Ministerio de EconomĂa y Competitividad of Spain (TEC2016-77242-C3-1-R)"This work was supported by the Comunidad de Madrid and FEDER Program (S2018/NMT-4326), the Ministerio de EconomĂa y Competitividad of Spain (TEC2013-47342-C2-2-R and TEC2016-76021-C2-2-R), the FEDER/Ministerio de Ciencia, InnovaciĂłn y Universidades and Agencia Estatal de InvestigaciĂłn (RTC2017-6321-1, PID2019-109072RB-C31 and PID2019-107270RB-C21). The authors also acknowledge the support by the Ministry of National Defense of Poland (GBMON/13-995/2018/WAT), Military University of Technology (Grant no. 23-895)
Low-energy interaction of composite spin-half systems with scalar and vector fields
We consider a composite spin-half particle moving in spatially-varying scalar
and vector fields. The vector field is assumed to couple to a conserved charge,
but no assumption is made about either the structure of the composite or its
coupling to the scalar field. A general form for the piece of the spin-orbit
interaction of the composite with the scalar and vector fields which is
first-order in momentum transfer and second-order in the fields is
derived.Comment: 10 pages, RevTe
Theoretical issues of small physics
The perturbative QCD predictions concerning deep inelastic scattering at low
are summarized. The theoretical framework based on the leading log
resummation and factorization theorem is described and some recent
developments concerning the BFKL equation and its generalization are discussed.
The QCD expectations concerning the small behaviour of the spin dependent
structure function are briefly summarized and the importance of
the double logarithmic terms which sum contributions containing the leading
powers of is emphasised. The role of studying final states
in deep inelastic scattering for revealing the details of the underlying
dynamics at low is pointed out and some dedicated measurements, like deep
inelastic scattering accompanied by an energetic jet, the measurement of the
transverse energy flow etc., are briefly discussed.Comment: 17 pages, LATEX, 7 uuencoded eps figures include
The Regge Limit for Green Functions in Conformal Field Theory
We define a Regge limit for off-shell Green functions in quantum field
theory, and study it in the particular case of conformal field theories (CFT).
Our limit differs from that defined in arXiv:0801.3002, the latter being only a
particular corner of the Regge regime. By studying the limit for free CFTs, we
are able to reproduce the Low-Nussinov, BFKL approach to the pomeron at weak
coupling. The dominance of Feynman graphs where only two high momentum lines
are exchanged in the t-channel, follows simply from the free field analysis. We
can then define the BFKL kernel in terms of the two point function of a simple
light-like bilocal operator. We also include a brief discussion of the gravity
dual predictions for the Regge limit at strong coupling.Comment: 23 pages 2 figures, v2: Clarification of relation of the Regge limit
defined here and previous work in CFT. Clarification of causal orderings in
the limit. References adde
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