3,443 research outputs found
Estimation of temporal and spatial variations in groundwater recharge in unconfined sand aquifers using Scots pine inventories
Acknowledgements. This study was made possible through funding from the EU 7th Framework programme GENESIS (contract number 226536), AQVI project (no. 128377) in Academy of Finland AKVA research programme, the Renlund Foundation, VALUE doctoral school and Maa- ja vesitekniikan tuki ry. We would like to express our gratitude to Geological survey of Finland, Finnish Forest Administration (MetsÀhallitus) and Finnish Forest Centre (MetsÀkeskus), Finnish meteorological institute, Finnish environmental administration and National land survey of Finland for providing data sets and expert knowledge that made this study possible in its current extent. To reproduce the research in the paper, data from above-mentioned agencies can be made available for purchase on request from the corresponding agency, other data can be provided by the corresponding author upon request. We thank Per-Erik Jansson for his assistance with the CoupModel and Jarkko Okkonen (GTK), anonymous reviewer, and Angelo Basile for their critical comments that significantly improved the manuscript.Peer reviewedPublisher PD
Dipolar depletion effect on the differential capacitance of carbon based materials
The remarkably low experimental values of the capacitance data of carbon
based materials in contact with water solvent needs to be explained from a
microscopic theory in order to optimize the efficiency of these materials. We
show that this experimental result can be explained by the dielectric screening
deficiency of the electrostatic potential, which in turn results from the
interfacial solvent depletion effect driven by image dipole interactions. We
show this by deriving from the microscopic system Hamiltonian a non-mean-field
dipolar Poisson-Boltzmann equation. This can account for the interaction of
solvent molecules with their electrostatic image resulting from the dielectric
discontinuity between the solvent medium and the substrate. The predictions of
the extended dipolar Poisson-Boltzmann equation for the differential
capacitance are compared with experimental data and good agreement is found
without any fitting parameters
Influence of Disorder Strength on Phase Field Models of Interfacial Growth
We study the influence of disorder strength on the interface roughening
process in a phase-field model with locally conserved dynamics. We consider two
cases where the mobility coefficient multiplying the locally conserved current
is either constant throughout the system (the two-sided model) or becomes zero
in the phase into which the interface advances (one-sided model). In the limit
of weak disorder, both models are completely equivalent and can reproduce the
physical process of a fluid diffusively invading a porous media, where
super-rough scaling of the interface fluctuations occurs. On the other hand,
increasing disorder causes the scaling properties to change to intrinsic
anomalous scaling. In the limit of strong disorder this behavior prevails for
the one-sided model, whereas for the two-sided case, nucleation of domains in
front of the invading front are observed.Comment: Accepted for publication in PR
Instability and wavelength selection during step flow growth of metal surfaces vicinal to fcc(001)
We study the onset and development of ledge instabilities during growth of
vicinal metal surfaces using kinetic Monte Carlo simulations. We observe the
formation of periodic patterns at [110] close packed step edges on surfaces
vicinal to fcc(001) under realistic molecular beam epitaxy conditions. The
corresponding wavelength and its temperature dependence are studied by
monitoring the autocorrelation function for step edge position. Simulations
suggest that the ledge instability on fcc(1,1,m) vicinal surfaces is controlled
by the strong kink Ehrlich-Schwoebel barrier, with the wavelength determined by
dimer nucleation at the step edge. Our results are in agreement with recent
continuum theoretical predictions, and experiments on Cu(1,1,17) vicinal
surfaces.Comment: 4 pages, 4 figures, RevTe
Quantum Treatment for Bose-Einstein Condensation in Non-Equilibrium Systems
We develop an approach based on stochastic quantum trajectories for an
incoherently pumped system of interacting bosons relaxing their energy in a
thermal reservoir. Our approach enables the study of the versatile coherence
properties of the system. We apply the model to exciton polaritons in a
semiconductor microcavity. Our results demonstrate the onset of macroscopic
occupation in the lowest-energy mode accompanied by the establishment of both
temporal and spatial coherence. We show that temporal coherence exhibits a
transition from a thermal to coherent statistics and the spatial coherence
reveals off-diagonal long-range order.Comment: 5 Pages, 3 figure
Comment on: `Pipe Network Model for Scaling of Dynamic Interfaces in Porous Media'
We argue that a proposed exponent identity [Phys. Rev. Lett 85, 1238 (2000)]
for interface roughening in spontaneous imbibition is wrong. It rests on the
assumption that the fluctuations are controlled by a single time scale, but
liquid conservation imposes two distinct time scales.Comment: 1 page, to appear in Phys. Rev. Let
Kinetic Roughening in Slow Combustion of Paper
Results of experiments on the dynamics and kinetic roughening of
one-dimensional slow-combustion fronts in three grades of paper are reported.
Extensive averaging of the data allows a detailed analysis of the spatial and
temporal development of the interface fluctuations. The asymptotic scaling
properties, on long length and time scales, are well described by the
Kardar-Parisi-Zhang (KPZ) equation with short-range, uncorrelated noise. To
obtain a more detailed picture of the strong-coupling fixed point,
characteristic of the KPZ universality class, universal amplitude ratios, and
the universal coupling constant are computed from the data and found to be in
good agreement with theory. Below the spatial and temporal scales at which a
cross-over takes place to the standard KPZ behavior, the fronts display higher
apparent exponents and apparent multiscaling. In this regime the interface
velocities are spatially and temporally correlated, and the distribution of the
magnitudes of the effective noise has a power-law tail. The relation of the
observed short-range behavior and the noise as determined from the local
velocity fluctuations is discussed.Comment: RevTeX v3.1, 13 pages, 12 Postscript figures (uses epsf.sty), 3
tables; submitted to Phys. Rev.
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