24,983 research outputs found
Condensation and coexistence in a two-species driven model
Condensation transition in two-species driven systems in a ring geometry is
studied in the case where current-density relation of a domain of particles
exhibits two degenerate maxima. It is found that the two maximal current phases
coexist both in the fluctuating domains of the fluid and in the condensate,
when it exists. This has a profound effect on the steady state properties of
the model. In particular, phase separation becomes more favorable, as compared
with the case of a single maximum in the current-density relation. Moreover, a
selection mechanism imposes equal currents flowing out of the condensate,
resulting in a neutral fluid even when the total number of particles of the two
species are not equal. In this case the particle imbalance shows up only in the
condensate
Transonic flow in a converging-diverging nozzle Final report
Transonic equations of motion for convergent-divergent nozzl
Stress response function of a granular layer: quantitative comparison between experiments and isotropic elasticity
We measured the vertical pressure response function of a layer of sand
submitted to a localized normal force at its surface. We found that this
response profile depends on the way the layer has been prepared: all profiles
show a single centered peak whose width scales with the thickness of the layer,
but a dense packing gives a wider peak than a loose one. We calculate the
prediction of isotropic elastic theory in presence of a bottom boundary and
compare it to the data. We found that the theory gives the right scaling and
the correct qualitative shape, but fails to really fit the data.Comment: 22 pages, 9 figures, submitted to Euro. Phys. J.
Coarsening of a Class of Driven Striped Structures
The coarsening process in a class of driven systems exhibiting striped
structures is studied. The dynamics is governed by the motion of the driven
interfaces between the stripes. When two interfaces meet they coalesce thus
giving rise to a coarsening process in which l(t), the average width of a
stripe, grows with time. This is a generalization of the reaction-diffusion
process A + A -> A to the case of extended coalescing objects, namely, the
interfaces. Scaling arguments which relate the coarsening process to the
evolution of a single driven interface are given, yielding growth laws for
l(t), for both short and long time. We introduce a simple microscopic model for
this process. Numerical simulations of the model confirm the scaling picture
and growth laws. The results are compared to the case where the stripes are not
driven and different growth laws arise
Detection of Prolonged Diapause of Northern Corn Rootworm in Michigan (Coleoptera: Chrysomelidae)
Prolonged diapause of northern corn rootworm, while known from other Midwestern states, has not previously been reported in Michigan. Populations of northern corn rootworm, (Diabrotica barberi) from two first-year corn fields in Genesee County, Michigan were examined for prolonged egg diapause. Pro- longed diapause was suspected in these populations due to an unusually high proportion of northern versus western corn rootworms in these fields. Eggs obtained from females collected at these sites were reared in the laboratory for two years. The presence of the prolonged diapause trait was confirmed in one population by eggs which hatched following two simulated winters (7.3%). None of the eggs m the second population hatched following the second chill period, however, some eggs in this population remained in apparent diapause at the end of two years. The potential for using observed population shifts in favor of D. barberi as an early warning of the expansion of prolonged diapause in a population is discussed
Modelling one-dimensional driven diffusive systems by the Zero-Range Process
The recently introduced correspondence between one-dimensional two-species
driven models and the Zero-Range Process is extended to study the case where
the densities of the two species need not be equal. The correspondence is
formulated through the length dependence of the current emitted from a particle
domain. A direct numerical method for evaluating this current is introduced,
and used to test the assumptions underlying this approach. In addition, a model
for isolated domain dynamics is introduced, which provides a simple way to
calculate the current also for the non-equal density case. This approach is
demonstrated and applied to a particular two-species model, where a phase
separation transition line is calculated
Synthesis of polyethers of hexafluorobenzene and hexafluoropentanediol
Two new polyethers, poly /hexafluoropentamethylene tetrafluoro-p-phenylene ether/ and a completely hydroxyl-terminated polyether, is prepared by reactions of hexafluorobenzene with hexafluoropentanediol. The polyethers can be prepared as low molecular weight oils, as intermediate molecular weight waxes, or as high molecular weight elastomers
Inflation and financial market performance
An exploration of the cross-sectional relationship between inflation and an array of indicators of financial market conditions, using time-averaged data covering several decades and a large number of countries.Financial markets ; Inflation (Finance)
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