9 research outputs found
Thiopentone sedation for sedation of acutely agitated, violent, intoxicated patients: Evaluation of 2 cases
Two cases of violent, drug-intoxicated patients who presented considerable problems in management, and were resistant to standard sedative agents, are described. Effective and safe sedation, without the need for full anaesthesia and endotracheal intubation, was achieved using titrated doses of thiopentone. The merits of selecting this agent in these circumstances are discussed
Scaling prediction for self-avoiding polygons revisited
We analyse new exact enumeration data for self-avoiding polygons, counted by
perimeter and area on the square, triangular and hexagonal lattices. In
extending earlier analyses, we focus on the perimeter moments in the vicinity
of the bicritical point. We also consider the shape of the critical curve near
the bicritical point, which describes the crossover to the branched polymer
phase. Our recently conjectured expression for the scaling function of rooted
self-avoiding polygons is further supported. For (unrooted) self-avoiding
polygons, the analysis reveals the presence of an additional additive term with
a new universal amplitude. We conjecture the exact value of this amplitude.Comment: 17 pages, 3 figure
Area distribution of the planar random loop boundary
We numerically investigate the area statistics of the outer boundary of
planar random loops, on the square and triangular lattices. Our Monte Carlo
simulations suggest that the underlying limit distribution is the Airy
distribution, which was recently found to appear also as area distribution in
the model of self-avoiding loops.Comment: 10 pages, 2 figures. v2: minor changes, version as publishe
Exact sampling of self-avoiding paths via discrete Schramm-Loewner evolution
We present an algorithm, based on the iteration of conformal maps, that
produces independent samples of self-avoiding paths in the plane. It is a
discrete process approximating radial Schramm-Loewner evolution growing to
infinity. We focus on the problem of reproducing the parametrization
corresponding to that of lattice models, namely self-avoiding walks on the
lattice, and we propose a strategy that gives rise to discrete paths where
consecutive points lie an approximately constant distance apart from each
other. This new method allows us to tackle two non-trivial features of
self-avoiding walks that critically depend on the parametrization: the
asphericity of a portion of chain and the correction-to-scaling exponent.Comment: 18 pages, 4 figures. Some sections rewritten (including title and
abstract), numerical results added, references added. Accepted for
publication in J. Stat. Phy
Role of Transient Co-Subcarbonyls in Ostwald Ripening Sintering of Cobalt Supported on γ‑Alumina Surfaces
The
stability and mobility of atomic cobalt and of cobalt subcarbonyl
species on γ-Al<sub>2</sub>O<sub>3</sub> surfaces have been
investigated using density functional theory (DFT) with a view to
elucidate possible mobile species on these surfaces, which can act
as agents in the Ostwald ripening process. The two most stable alumina
surfaces γ-Al<sub>2</sub>O<sub>3</sub>(100) and γ-Al<sub>2</sub>O<sub>3</sub>(110) were probed at different levels of hydration.
The stability of cobalt subcarbonyl species on γ-Al<sub>2</sub>O<sub>3</sub>(100) at high partial pressure of CO (10 bar) increases
with increasing number of CO ligands attached to the central cobalt
atom up to CoÂ(CO)<sub>3</sub> but exhibits a more complex behavior
on γ-Al<sub>2</sub>O<sub>3</sub>(110). The effect of the hydration
level on the stability of cobalt subcarbonyls was investigated. The
interpretation of the DFT results in a thermodynamic model shows that
at equilibrium the main cobalt subcarbonyl species present on the
alumina surface at ca. 500K in the presence of CO are CoÂ(CO)<sub>3</sub> and CoÂ(CO)<sub>4</sub>, with CoÂ(CO)<sub>3</sub> being the dominant
species on dry γ-Al<sub>2</sub>O<sub>3</sub>(100) and wet γ-Al<sub>2</sub>O<sub>3</sub>(110). The fractional coverage of these species
on a wetted alumina surface is lower than that on a dry alumina surface.
The mobility of surface species was probed by exploring the potential
energy surface of the adsorbed species on γ-Al<sub>2</sub>O<sub>3</sub>(100) and γ-Al<sub>2</sub>O<sub>3</sub>(110) at different
hydration levels (Θ<sub>OH</sub> = 8.5 and 17.7 OH/nm<sup>2</sup>, respectively). Cobalt subcarbonyl species have a high mobility
with activation barriers as low as 0.5 eV. It is argued that these
species may contribute to the sintering process