Linear theory of wave generation by a moving bottom

The computation of long wave propagation through the ocean obviously depends on the initial condition. When the waves are generated by a moving bottom, a traditional approach consists in translating the ``frozen'' sea bed deformation to the free surface and propagating it. The present study shows the differences between the classical approach (passive generation) and the active generation where the bottom motion is included. The analytical solutions presented here exhibit some of the drawbacks of passive generation. The linearized solutions seem to be sufficient to consider the generation of water waves by a moving bottom.Comment: 9 pages, 2 figure

Growth and development of common pine on lands,taken out from agricultural use,depending on methods and ways of creation

Here there are results of studies of common pine plantations created in 2004 by the line-hole seeding, with the help of manual and automated planting of two-year seedlings into the furrow bottom after plowingby the plow ПКЛ-70 on the plot, taken out from agricultural use. It is found out that creation of forest plantation of the common pine by sowing seeds on former agricultural lands is not reliable, because a large number of plants die in the first years of life, and the remaining plants occupy the area unevenly, arranged in rows of clumps. Pine plantations created with the help of manual and automated planting grow successfully and at the age of 7 have no significant differences in taxation indices

Classification of soils of Negoreloye forestry station

Classification of soils is to be done by codes, which indicate the productivity (bonitet), the reference (prospective) tree species, soil evaluation in points and the index shows class of forests (1st – forest of insufficient moisture, 2nd – of excessive moisture). In a forest station there have identified 16 types of soils by codes: from IIIP561to IIIAl142. Soil IP771(60,7 %) is prevailing. Soils IIP681 and IаP891 occupy a much smaller area (13%). In the second class of forests, which account for 12% of the most frequently occurring soils IP772(6.4%) and IIP682(2.7%). The average score of forest stands is 45 and that of soils is 75 points. With an average stand density of 0.72 the stands evaluation is below the maximum by 55 points (100 – 45), due to the group of forests it is lower by 2 (100 – 98), due to site conditions by 23 (98 – 75), due to stand density by 21 (75 – 54) and due to species composition by 9 points. Forest productivity may be increased by 30 points by controlling the species composition and stand density

Dendrological scales of spruce european of 5–7th groups of plants in the territory of Belarus

Spruce forests belonging to 5–7th groups of plants have I–Ib class of bonitet and are the most productive. Dendrological scales of spruce forests have an extension 104 years (1888–1991). Index values in the spruce forests of the 5th group plantings ranged for late wood within 0.66–1.44, for early wood – 0.61–1.30, for treering as a whole – 0.62–1.29. In spruce forests of 6th group index values fluctuated for late wood within 0.72–1.99, for ea rly – 0.63–1.26, for tree-ring as a whole – 0.67– 1.24. In spruce forests of 7th group index values fluctuated for late wood within 0.47–1.58, for early – 0.41–1.86, for treering as a whole – 0.42–1.75. Coefficients of variation of indices width of tree rings were as follows: for spruce plantations 5th group 13% for spruce 6th group – 11% for spruce 7th group – 18%, which corresponds to the lower rate of normal variation

A Galerkin boundary element method for high frequency scattering by convex polygons

In this paper we consider the problem of time-harmonic acoustic scattering in two dimensions by convex polygons. Standard boundary or finite element methods for acoustic scattering problems have a computational cost that grows at least linearly as a function of the frequency of the incident wave. Here we present a novel Galerkin boundary element method, which uses an approximation space consisting of the products of plane waves with piecewise polynomials supported on a graded mesh, with smaller elements closer to the corners of the polygon. We prove that the best approximation from the approximation space requires a number of degrees of freedom to achieve a prescribed level of accuracy that grows only logarithmically as a function of the frequency. Numerical results demonstrate the same logarithmic dependence on the frequency for the Galerkin method solution. Our boundary element method is a discretization of a well-known second kind combined-layer-potential integral equation. We provide a proof that this equation and its adjoint are well-posed and equivalent to the boundary value problem in a Sobolev space setting for general Lipschitz domains

Diaminodiphenylmethane Sensitization in north-eastern Italy from 1996 to 2012

BACKGROUND: 4,4'-Diaminodiphenylmethane (DDM) is an aromatic amine used as a hardener, insulator and anticorrosive. Exposure implies risk of being sensitized and developing contact dermatitis. OBJECTIVE: The aim of this study was to determine the occurrence of contact sensitization to DDM among patients with contact dermatitis and the role of occupational exposure. PATIENTS AND METHODS: From 1996 to 2012, 24 056 consecutive patients with suspected allergic contact dermatitis were patch tested in north-eastern Italy. Individual characteristics were collected through a standardized questionnaire in eight departments of dermatology and occupational medicine. RESULTS: The overall prevalence of DDM sensitization was 2.5% (n = 599) with a decreasing trend in considered years. Trieste area had the higher prevalence of sensitization (3.2%). Mechanics and chemical industry workers had a significant higher risk of being sensitized to DDM. CONCLUSION: DDM sensitization is decreasing in years and is associated with some occupational exposures

In vitro permeability of silver nanoparticles through porcine oromucosal membrane

Silver nanoparticles (AgNPs) can come in contact with human oral mucosa due to their wide use infood industry and hygiene devices. We evaluate transmucosal absorption of 19 nm AgNPs using excisedporcine buccal mucosa applied on Franz diffusion cells. Two donor solutions were used: one containingAgNPs (0.5 g/L) and one derived from the ultrafiltration of the former and containing only Ag in its solubleform. Experiments were carried out separately for 4 h. Silver flux permeation was demonstrated throughoral mucosa, showing similar values for AgNPs (6.8 \ub1 4.5 ng cm 122h 121) and Ag ions (5.2 \ub1 4.3 ng cm 122h 121).Our study demonstrates that silver can permeate the oromucosal barrier and that absorption is sub-stantially due to Ag ions, since no permeation difference was found using the two solutions. Mucosalabsorption has to be considered in further risk assessment studies

Comparison between three-dimensional linear and nonlinear tsunami generation models

The modeling of tsunami generation is an essential phase in understanding tsunamis. For tsunamis generated by underwater earthquakes, it involves the modeling of the sea bottom motion as well as the resulting motion of the water above it. A comparison between various models for three-dimensional water motion, ranging from linear theory to fully nonlinear theory, is performed. It is found that for most events the linear theory is sufficient. However, in some cases, more sophisticated theories are needed. Moreover, it is shown that the passive approach in which the seafloor deformation is simply translated to the ocean surface is not always equivalent to the active approach in which the bottom motion is taken into account, even if the deformation is supposed to be instantaneous.Comment: 39 pages, 16 figures; Accepted to Theoretical and Computational Fluid Dynamics. Several references have been adde

Localized Dissipation in Fermionic Quantum Wires

Localized dissipation in many-body quantum systems represents an emergent focal point of non-equilibrium physics. In recent experiments, localized particle losses were realized in ultracold atomic gases, thus opening up new avenues for investigating the interplay between many-body and non-equilibrium effects. The main focus of this work is the theoretical study of collective phenomena in one-dimensional systems of interacting spinless fermions subject to a localized loss. This model constitutes a non-equilibrium counterpart of the paradigmatic Kane-Fisher potential barrier problem. In particular, strong interaction effects emerge due to the gapless nature of the system. We show that the loss and transport properties of the quantum wire in the presence of a localized loss are drastically modified by interactions as a result of the interplay between coherent and incoherent processes. In experiments with localized losses, a manifestation of the quantum Zeno effect is encountered, which can be described exhaustively in terms of local, microscopic physics. In contrast, we demonstrate that the interplay of gapless quantum fluctuations and particle interactions with the localized dissipation leads to an instance of the quantum Zeno effect of genuine many-body nature. After the localized losses are switched on, a non-equilibrium steady state emerges in the quantum wire. We derive exact results for the properties of this steady state in the non-interacting limit and formulate a theoretical description of the depletion processes by introducing the momentum-dependent loss probability of modes. Remarkably, we find that coherence properties of the initial state persist, leading to the formation of Friedel oscillations near the loss site. The presence of interactions between the fermions modifies the dynamics in the wire and leads to an energy-dependent renormalization of loss processes. We find that the loss probability is strongly renormalized for modes with an energy close to the Fermi energy, leading to the suppression of losses at the Fermi level. In the case of repulsive interactions, the suppression of losses is accompanied by the loss site becoming completely opaque, which establishes a fluctuation-induced quantum Zeno effect. For attractive interactions, instead, the localized loss becomes fully transparent to particles at the Fermi level, resulting accordingly in the suppression of losses as a fluctuation-induced transparency. The strong modifications of the loss properties are reflected in observables such as the momentum distribution in the wire, exhibiting an increased occupation at the Fermi momentum. In addition, we study the influence of self-thermalization effects on the renormalization of the effective dissipation strength. Here, we identify regimes where the generation of an effective temperature is sufficiently weak to achieve significant renormalization. Furthermore, the microscopic quantum Zeno effect affects the spectral properties of the non-Hermitian Hamiltonian associated with a localized loss for a lattice model. Here, a sharp reorganization of the spectrum is encountered at a critical dissipation strength, causing a characteristic signature in the response properties of the wire. We investigate the interplay of interactions in the wire and localized dissipation within three complementary approaches. In a microscopic real-space renormalization group analysis the physical mechanisms behind the modified depletion properties are particularly transparent. Within a dynamical Hartree-Fock approximation the resulting effects on observables such as the momentum distribution in the non-equilibrium steady states can be studied. Finally, an effective Luttinger liquid description demonstrates the universality of the findings and enables the investigation of mode-coupling effects