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 (Metsähallitus) and Finnish Forest Centre (Metsäkeskus), 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

Eighth-order phase-field-crystal model for two-dimensional crystallization

We present a derivation of the recently proposed eighth order phase field crystal model [Jaatinen et al., Phys. Rev. E 80, 031602 (2009)] for the crystallization of a solid from an undercooled melt. The model is used to study the planar growth of a two dimensional hexagonal crystal, and the results are compared against similar results from dynamical density functional theory of Marconi and Tarazona, as well as other phase field crystal models. We find that among the phase field crystal models studied, the eighth order fitting scheme gives results in good agreement with the density functional theory for both static and dynamic properties, suggesting it is an accurate and computationally efficient approximation to the density functional theory

Controlling Polymer Capture and Translocation by Electrostatic Polymer-Pore Interactions

Polymer translocation experiments typically involve anionic polyelectrolytes such as DNA molecules driven through negatively charged nanopores. Quantitative modelling of polymer capture to the nanopore followed by translocation therefore necessitates the consideration of the electrostatic barrier resulting from like-charge polymer-pore interactions. To this end, in this work we couple mean-field level electrohydrodynamic equations with the Smoluchowski formalism to characterize the interplay between the electrostatic barrier, the electrophoretic drift, and the electro-osmotic liquid flow. In particular, we find that due to distinct ion density regimes where the salt screening of the drift and barrier effects occur, there exists a characteristic salt concentration maximizing the probability of barrier-limited polymer capture into the pore. We also show that in the barrier-dominated regime, the polymer translocation time increases exponentially with the membrane charge and decays exponentially fast with the pore radius and the salt concentration. These results suggest that the alteration of these parameters in the barrier-driven regime can be an efficient way to control the duration of the translocation process and facilitate more accurate measurements of the ionic current signal in the pore

Using isotopes to constrain water flux and age estimates in snow-influenced catchments using the STARR (Spatially distributed Tracer-Aided Rainfall-Runoff) model

Acknowledgements. This work was funded by the NERC/JPI SIWA project (NE/M019896/1) and the European Research Council ERC (project GA 335910 VeWa). Numerical simulations were performed using the Maxwell High Performance Computing Cluster of the University of Aberdeen IT Service, provided by Dell Inc. and supported by Alces Software. The isotope work in Krycklan is funded by the KAW Branch-Point project together with SKB and SITES. We would like to thank Marjolein van Hui- jgevoort for her help with the STARR code, and Masaki Hayashi and two anonymous reviewers for their insightful suggestions that significantly improved the paper. The Supplement related to this article is available online at https://doi.org/10.5194/hess-21-5089-2017-supplement.Peer reviewedPublisher PD

On-chip Maxwell's demon as an information-powered refrigerator

We present an experimental realization of an autonomous Maxwell's Demon, which extracts microscopic information from a System and reduces its entropy by applying feedback. It is based on two capacitively coupled single electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the Demon and the System as well as their mutual information exchange. The operation of the Demon is directly observed as a temperature drop in the System. We also observe a simultaneous temperature rise in the Demon arising from the thermodynamic cost of generating the mutual information.Comment: 10 pages, 7 figure

Effects of quenched impurities on surface diffusion, spreading, and ordering of O/W(110)

We study how quenched impurities affect the surfacediffusion and ordering of strongly interactingadsorbate atoms on surfaces. To this end, we carry out Monte Carlo simulations for a lattice-gas model of O/W(110), including small concentrations of immobile impurities which block their adsorption sites. We examine the behavior of the diffusion coefficients and order parameters as a function of coverage corresponding to various ordered phases at low temperatures. The effects of impurities are examined under both equilibrium and nonequilibrium conditions, and the results are compared to recent studies on a completely clean surface. We find that even minute impurity concentrations affect the diffusion behavior considerably in equilibrium. The effects are strongest in ordered phases and close to phase boundaries, where quenched impurities lead to a reduction of order, which in turn leads to significant changes in the collective diffusion and phase behavior. As the impurity concentration is increased to a level of a few percent of the total surface area, the reduction in order becomes particularly prominent at high coverages. Further studies under nonequilibrium conditions reveal that nonequilibrium effects are strong in the absence of impurities, while for surfaces covered by impurities the nonequilibrium effects are relatively weaker.Peer reviewe

Dynamics near the Surface Reconstruction of W(100)

Using Brownian molecular dynamics simulation, we study the surface dynamics near the reconstruction transition of W(100) via a model Hamiltonian. Results for the softening and broadening of the surface phonon spectrum near the transition are compared with previous calculations and with He atom scattering data. From the critical behavior of the central peak in the dynamical structure factor, we also estimate the exponent of the power law anomaly for adatom diffusion near the transition temperature.Comment: 8 pages, 8 figures, to appear in Phys. Rev.

Linear chemically sensitive electron tomography using DualEELS and dictionary-based compressed sensing

We have investigated the use of DualEELS in elementally sensitive tilt series tomography in the scanning transmission electron microscope. A procedure is implemented using deconvolution to remove the effects of multiple scattering, followed by normalisation by the zero loss peak intensity. This is performed to produce a signal that is linearly dependent on the projected density of the element in each pixel. This method is compared with one that does not include deconvolution (although normalisation by the zero loss peak intensity is still performed). Additionaly, we compare the 3D reconstruction using a new compressed sensing algorithm, DLET, with the well-established SIRT algorithm. VC precipitates, which are extracted from a steel on a carbon replica, are used in this study. It is found that the use of this linear signal results in a very even density throughout the precipitates. However, when deconvolution is omitted, a slight density reduction is observed in the cores of the precipitates (a so-called cupping artefact). Additionally, it is clearly demonstrated that the 3D morphology is much better reproduced using the DLET algorithm, with very little elongation in the missing wedge direction. It is therefore concluded that reliable elementally sensitive tilt tomography using EELS requires the appropriate use of DualEELS together with a suitable reconstruction algorithm, such as the compressed sensing based reconstruction algorithm used here, to make the best use of the limited data volume and signal to noise inherent in core-loss EELS

Airborne measurements of cloud-forming nuclei and aerosol particles in stabilized ground clouds produced by solid rocket booster firings

Airborne measurements of cloud volumes, ice nuclei and cloud condensation nuclei, liquid particles, and aerosol particles were obtained from stabilized ground clouds (SGCs) produced by Titan 3 launches at Kennedy Space Center, 20 August and 5 September 1977. The SGCs were bright, white, cumulus clouds early in their life and contained up to 3.5 g/m3 of liquid in micron to millimeter size droplets. The measured cloud volumes were 40 to 60 cu km five hours after launch. The SGCs contained high concentrations of cloud condensation nuclei active at 0.2%, 0.5%, and 1.0% supersaturation for periods of three to five hours. The SGCs also contained high concentrations of submicron particles. Three modes existed in the particle population: a 0.05 to 0.1 micron mode composed of aluminum-containing particles, a 0.2 to 0.8 micron mode, and a 2.0 to 10 micron mode composed of particles that contained primarily aluminum