2,450 research outputs found
Wetting on Lines and Lattices of Cylinders
This paper discusses wetting and capillary condensation transitions on a line
and a rectangular array of cylinders using an interface potential formalism.
For a line of cylinders, there is a capillary condensation transition followed
by complete wetting if the cylinders are sufficiently close together. Both
transitions disappear as the cylinder separation is increased. The dependence
of the wetting phase diagram of a rectangular array of cylinders is discussed
as a function of the chemical potential, substrate--fluid interaction strength
and surface tension.Comment: 17 pages in total: 11 pages of Latex document and 6 pages of figures,
Latex Version 2.09, OUTP-93-40
Fluid or fuel? The context of consuming a beverage is important for satiety
Energy-containing beverages have a weak effect on satiety, limited by their fluid characteristics and perhaps because they are not considered ‘food’. This study investigated whether the context of consuming a beverage can influence the satiating power of its nutrients. Eighty participants consumed a lower- (LE, 75 kcal) and higher-energy (HE, 272 kcal) version of a beverage (covertly manipulated within-groups) on two test days, in one of four beverage contexts (between-groups): thin versions of the test-drinks were consumed as a thirst-quenching drink (n = 20), a filling snack (n = 20), or without additional information (n = 20). A fourth group consumed subtly thicker versions of the beverages without additional information (n = 20). Lunch intake 60 minutes later depended on the beverage context and energy content (p = 0.030): participants who consumed the thin beverages without additional information ate a similar amount of lunch after the LE and HE versions (LE = 475 kcal, HE = 464 kcal; p = 0.690) as did those participants who believed the beverages were designed to quench-thirst (LE = 442 kcal, HE = 402 kcal; p = 0.213), despite consuming an additional 197 kcal in the HE beverage. Consuming the beverage as a filling snack led participants to consume less at lunch after the HE beverage compared to the LE version (LE = 506 kcal, HE = 437 kcal; p = 0.025). This effect was also seen when the beverages were subtly thicker, with participants in this group displaying the largest response to the beverage’s energy content, consuming less at lunch after the HE version (LE = 552 kcal, HE = 415 kcal; p<0.001). These data indicate that beliefs about the consequences of consuming a beverage can affect the impact of its nutrients on appetite regulation and provide further evidence that a beverage’s sensory characteristics can limit its satiating power
Optimising foods for satiety
Foods that generate strong satiety sensations have obvious ben- efits for weight management. This review builds on the under- standing that a food’s satiating power is dependent on the amount of protein, carbohydrate, fat and fibre it contains by examining evidence that the consumer’s sensory and cognitive appraisal of the food is also important. It is concluded that numerous features of a food product can be manipulated to enhance the consumer’s experience of satiety but the combi- nation of these features will ultimately determine its effect on appetite control. Taking this integrated approach to satiety will optimise the development of high satiety foods
Role of friction in multidefect ordering
We use continuum simulations to study the impact of friction on the ordering
of defects in an active nematic. Even in a frictionless system, +1/2 defects
tend to align side-by-side and orient antiparallel reflecting their propensity
to form, and circulate with, flow vortices. Increasing friction enhances the
effectiveness of the defect-defect interactions, and defects form dynamically
evolving, large scale, positionally and orientationally-ordered structures
which can be explained as a competition between hexagonal packing, preferred by
the -1/2 defects, and rectangular packing preferred by the +1/2 defects
A Lattice Boltzmann Model of Binary Fluid Mixture
We introduce a lattice Boltzmann for simulating an immiscible binary fluid
mixture. Our collision rules are derived from a macroscopic thermodynamic
description of the fluid in a way motivated by the Cahn-Hilliard approach to
non-equilibrium dynamics. This ensures that a thermodynamically consistent
state is reached in equilibrium. The non-equilibrium dynamics is investigated
numerically and found to agree with simple analytic predictions in both the
one-phase and the two-phase region of the phase diagram.Comment: 12 pages + 4 eps figure
Effect of topology on dynamics of knots in polymers under tension
We use computer simulations to compare the dynamical behaviour of torus and
even-twist knots in polymers under tension. The knots diffuse through a
mechanism similar to reptation. Their friction coefficients grow linearly with
average knot length for both knot types. For similar complexity, however, the
torus knots diffuse faster than the even twist knots. The knot-length
auto-correlation function exhibits a slow relaxation time that can be linked to
a breathing mode. Its timescale depends on knot type, being typically longer
for torus than for even-twist knots. These differences in dynamical behaviour
are interpreted in terms of topological features of the knots.Comment: 6 pages, 8 figure
Complex dynamics of knotted filaments in shear flow
Coarse-grained simulations are used to demonstrate that knotted filaments in
shear flow at zero Reynolds number exhibit remarkably rich dynamic behaviour.
For stiff filaments that are weakly deformed by the shear forces, the knotted
filaments rotate like rigid objects in the flow. But away from this regime the
interplay between between shear forces and the flexibility of the filament
leads to intricate regular and chaotic modes of motion that can be divided into
distinct families. The set of accessible mode families depends to first order
on a dimensionless number that relates the filament length, the elastic
modulus, the friction per unit length and the shear rate.Comment: 6 pages, 6 figure
Low temperature phase diagram and critical behaviour of the four-state chiral clock model
The low temperature behaviour of the four-state chiral clock () model
is reexamined using a systematic low temperature series expansion of the free
energy. Previously obtained results for the low temperature phases are
corrected and the low temperature phase diagram is derived. In addition, the
phase transition from the modulated region to the high temperature paraphase is
shown to belong to the universality class of the 3d-XY model.Comment: 17 pages in ioplppt style, 3 figure
Cometary Astrometry
Modern techniques for making cometary astrometric observations, reducing these observations, using accurate reference star catalogs, and computing precise orbits and ephemerides are discussed in detail and recommendations and suggestions are given in each area
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