8,901 research outputs found
Integral formula for elliptic SOS models with domain walls and a reflecting end
In this paper we extend previous work of Galleas and the author to elliptic
SOS models. We demonstrate that the dynamical reflection algebra can be
exploited to obtain a functional equation characterizing the partition function
of an elliptic SOS model with domain-wall boundaries and one reflecting end.
Special attention is paid to the structure of the functional equation. Through
this approach we find a novel multiple-integral formula for that partition
function.Comment: 31 pages, 3 figures; v2: minor improvements, reference adde
Work Organisation and Innovation - Case Study: Rabobank, Netherlands
[Excerpt] Rabobank Nederland (RN) is part of Rabobank Group, which provides financial services and insurance. It is the largest financial services provider in the Netherlands. The group operates in 47 countries and has an employee base of 59,670 full-time equivalents (FTE). In the Netherlands RN has an employee base of 6,800 FTE, which is more or less equal to 8,500 employees. RN is a cooperative, located in Utrecht, and the administrative centre for 139 (2011) local cooperative Rabobanks. The local banks are not branches of RN as each of them has its own banking licence from the central Nederlandsche Bank. The joint employee base of the local Rabobanks is 27,000 FTE. The 139 local Rabobanks, RN and affiliates, provide services to some 10 million clients, including 1.9 million members (Rabobank Annual Report, 2011)
Resurrecting the partially isotropic Haldane-Shastry model
We present a new and simpler expression for the Hamiltonian of the partially
isotropic (XXZ-like) version of the Haldane-Shastry model, which was derived by
D. Uglov over two decades ago in an apparently little-known preprint. While
resembling the pairwise long-range form of the Haldane-Shastry model our
formula accounts for the multi-spin interactions obtained by Uglov. Our
expression is physically meaningful, makes hermiticity manifest, and is
computationally more efficient. We discuss the model's properties, including
its limits and (ordinary and quantum-affine) symmetries. In particular we
introduce the appropriate notions of translational invariance and momentum. We
review the model's exact spectrum found by Uglov for finite spin-chain length,
which parallels the isotropic case up to level splitting due to the anisotropy.
We also extend the partially isotropic model to higher rank, with
'spins', for which the spectrum is determined by -motifs.Comment: 5 pages, 1 figure, 1 table; v2: various minor changes and additions;
v3: 6 pages, 1 figure, 1 table; added proof of equality of formulae, minor
further changes; v4: minor changes; v5: minor chang
N-body simulations of star clusters
Two aspects of our recent N-body studies of star clusters are presented: (1)
What impact does mass segregation and selective mass loss have on integrated
photometry? (2) How well compare results from N-body simulations using NBODY4
and STARLAB/KIRA?Comment: 2 pages, 1 figure with 4 panels (in colour, not well visible in
black-and-white; figures screwed in PDF version, ok in postscript; to see
further details get the paper source). Conference proceedings for IAUS246
'Dynamical Evolution of Dense Stellar Systems', ed. E. Vesperini (Chief
Editor), M. Giersz, A. Sills, Capri, Sept. 2007; v2: references correcte
A numerical study of the F-model with domain-wall boundaries
We perform a numerical study of the F-model with domain-wall boundary
conditions. Various exact results are known for this particular case of the
six-vertex model, including closed expressions for the partition function for
any system size as well as its asymptotics and leading finite-size corrections.
To complement this picture we use a full lattice multi-cluster algorithm to
study equilibrium properties of this model for systems of moderate size, up to
L=512. We compare the energy to its exactly known large-L asymptotics. We
investigate the model's infinite-order phase transition by means of finite-size
scaling for an observable derived from the staggered polarization in order to
test the method put forward in our recent joint work with Duine and Barkema. In
addition we analyse local properties of the model. Our data are perfectly
consistent with analytical expressions for the arctic curves. We investigate
the structure inside the temperate region of the lattice, confirming the
oscillations in vertex densities that were first observed by Sylju{\aa}sen and
Zvonarev, and recently studied by Lyberg et al. We point out
'(anti)ferroelectric' oscillations close to the corresponding frozen regions as
well as 'higher-order' oscillations forming an intricate pattern with
saddle-point-like features.Comment: v4: 15 pages, 11 figures, 1 table; various minor improvements;
supplementary material available upon reques
Spring forward of woven fabric reinforced composites
Continuous-fibre-reinforced plastic products are usually formed at elevated temperatures. They exhibit distortions when they are cooled to room temperature and released from the mould. For example, the enclosed angle of an L-shaped product decreases, see Fig. 1. This effect is known as spring-forward. It is mainly due to the anisotropic thermal shrinkage of the composite, which is small in the fibre direction and relatively large in the direction normal to the fibres. The costs of forming a product with the demanded dimensions by trial and error are high. To reduce these costs, the objective of the research described in this paper is to develop a model, which predicts the occurring distortions
FDI, terrorism and the availability heuristic for U.S. investors before and after 9/11
We record the existence of an availability heuristic that is reflected in disaster myopia of U.S. investors and exists prior to the attacks of 9/11.
We argue that this is fueled by an aggregate experience hypothesis effect, resulting in a pronounced increase in the sensitivity of U.S. stock prices to terrorist attacks on foreign soil. After 9/11, stock prices react proportionally to the size of an attack and the share of FDI stock held in the region by the sector in which firms operate. This effect, non-existent prior to 2002, has become increasingly strong in recent years
Residual stresses in non-symmetrical carbon/epoxy laminates
The curvature of unsymmetrical [0/90] laminates moulded from AS4/8552 uni-directional tape has been measured. A linear thermoelastic approach has been applied to predict the related residual stress state before demoulding, giving an estimate of the stress induced by polymerisation strain. The results from the linear approach are confirmed by a viscoelastic finite element model including the cure conversion and related change in viscosity. It is concluded that the curvature measurement of unsymmetrical laminates is an accurate method for the prediction of the transverse residual stress, making it suitable as a benchmark for complex stress modelling
Mass fluxes for hot stars
In an attempt to understand the extraordinarily small mass-loss rates of
late-type O dwarfs, mass fluxes in the relevant part of (T_{eff}, g)-space are
derived from first principles using a previously-described code for
constructing moving reversing layers. From these mass fluxes, a weak-wind
domain is identified within which a star's rate of mass loss by a
radiatively-driven wind is less than that due to nuclear burning. The five
weak-wind stars recently analysed by Marcolino et al. (2009) fall within or at
the edge of this domain. But although the theoretical mass fluxes for these
stars are ~ 1.4 dex lower than those derived with the formula of Vink et al.
(2000), the observed rates are still not matched, a failure that may reflect
our poor understanding of low-density supersonic outflows.
Mass fluxes are also computed for two strong-wind O4 stars analysed by Bouret
et al. (2005). The predictions agree with the sharply reduced mass loss rates
found when Bouret et al. take wind clumping into account.Comment: Accepted by A&A; 6 pages, 5 figures; minor changes from v
- …