Search results for "conservation."
showing 10 items of 1994 documents
The pumice aggregates of Lipari Island (Aeolian Isles-Italy)
1984
In the Island of Lipari (Aeolian Archipelago) there is a large pumice deposit. The pumice is exploited in an open-cast mine through mechanical means and taken to crushing and screening plants. Aggregates for urban construction, gravel and powder are obtained. The aggregates are used in the manufacture of light concrete. Nowadays the possibility of using pumice aggregates in order to obtain light structural concrete is being studied.
Conservation Status of Some Peatbogs in Maramureş County
2016
AbstractPeat bogs and specially raised bogs are vulnerable ecosystems all over the world and they create refuges for some rare plant species. The aim of this paper is to provide information regarding the conservation status of five oligotrophic peat bogs situated in the volcanic mountains in the Oriental Chain of Carpathians, in Maramureș County. The studied peat bogs are: Tăul lui Dumitru (Dumitru Pond), Mlaștina Vlășinescu (Vlășinescu Peat bog), Iezeru Mare (Big Tarn), Tăul Chendroaiei (Chendroaiei Pond) and Tăul Negru (Black Pond), all of them have the status of nature reserve and under the IUCN categories they are included in category IV Habitat/Species Management Area (www.iucn.org, 20…
Eresus kollari (Araneae: Eresidae) calls for heathland management
2011
Northwest Europe’s largest heather-dominated sandy habitats are located in the nature reserve Lu¨neburgerHeide, Germany. Yet, even these appear to be losing their ability to support some of their stenotopic species such as theladybird spider, Eresus kollari Rossi 1846, and are thus becoming increasingly important for the preservation of thesespecies. The habitat requirements of this endangered spider species were investigated in order to obtain data that will helpstabilize the last remnants of the species’ population in northwest Germany. Several heathland habitats were surveyed bypitfall trapping during the mate-search period of the males. Two statistical methods were applied: logistic reg…
Land molluscs from the Isola delle Femmine Nature Reserve (north-western Sicily, Italy) (Gastropoda Architaenioglossa Pulmonata)
2021
The results of a study on the fauna of land molluscs from Isola delle Femmine Nature Reserve (NW Sicily, Italy) (Gastropoda Architaenioglossa Pulmonata) are here described. In this small island 23 species have been found, 6 of which are Sicilian endemic taxa. Siciliaria leucophryna microinsularis n. ssp. endemic to the Isola delle Femmine (or Isola di Fuori) is described. For each species ecological, distributional data and information on their presence on this island are provided.
Neutrino interaction classification with a convolutional neural network in the DUNE far detector
2020
The Deep Underground Neutrino Experiment is a next-generation neutrino oscillation experiment that aims to measure CP-violation in the neutrino sector as part of a wider physics program. A deep learning approach based on a convolutional neural network has been developed to provide highly efficient and pure selections of electron neutrino and muon neutrino charged-current interactions. The electron neutrino (antineutrino) selection efficiency peaks at 90% (94%) and exceeds 85% (90%) for reconstructed neutrino energies between 2–5 GeV. The muon neutrino (antineutrino) event selection is found to have a maximum efficiency of 96% (97%) and exceeds 90% (95%) efficiency for reconstructed neutrino…
Normal Coulomb Frames in $${\mathbb{R}}^{4}$$
2012
Now we consider two-dimensional surfaces immersed in Euclidean spaces \({\mathbb{R}}^{n+2}\) of arbitrary dimension. The construction of normal Coulomb frames turns out to be more intricate and requires a profound analysis of nonlinear elliptic systems in two variables. The Euler–Lagrange equations of the functional of total torsion are identified as non-linear elliptic systems with quadratic growth in the gradient, and, more exactly, the nonlinearity in the gradient is of so-called curl-type, while the Euler–Lagrange equations appear in a div-curl-form. We discuss the interplay between curvatures of the normal bundles and torsion properties of normal Coulomb frames. It turns out that such …
Entropy dissipation of moving mesh adaptation
2014
Non-uniform grids and mesh adaptation have become an important part of numerical approximations of differential equations over the past decades. It has been experimentally noted that mesh adaptation leads not only to locally improved solution but also to numerical stability of the underlying method. In this paper we consider nonlinear conservation laws and provide a method to perform the analysis of the moving mesh adaptation method, including both the mesh reconstruction and evolution of the solution. We moreover employ this method to extract sufficient conditions — on the adaptation of the mesh — that stabilize a numerical scheme in the sense of the entropy dissipation.
Infinite sets of conservation laws for linear and nonlinear field equations
1984
The relation between an infinite set of conservation laws of a linear field equation and the enveloping algebra of the space-time symmetry group is established. It is shown that each symmetric element of the enveloping algebra of the space-time symmetry group of a linear field equation generates a one-parameter group of symmetries of the field equation. The cases of the Maxwell and Dirac equations are studied in detail. Then it is shown that (at least in the sense of a power series in the ‘coupling constant’) the conservation laws of the linear case can be deformed to conservation laws of a nonlinear field equation which is obtained from the linear one by adding a nonlinear term invariant u…
Asymptotic Analysis of a Slightly Rarefied Gas with Nonlocal Boundary Conditions
2011
In this paper nonlocal boundary conditions for the Navier–Stokes equations are derived, starting from the Boltzmann equation in the limit for the Knudsen number being vanishingly small. In the same spirit of (Lombardo et al. in J. Stat. Phys. 130:69–82, 2008) where a nonlocal Poisson scattering kernel was introduced, a gaussian scattering kernel which models nonlocal interactions between the gas molecules and the wall boundary is proposed. It is proved to satisfy the global mass conservation and a generalized reciprocity relation. The asymptotic expansion of the boundary-value problem for the Boltzmann equation, provides, in the continuum limit, the Navier–Stokes equations associated with a…
Multilayered samples reconstructed by measuring Kα/Kβ or Lα/Lβ X-ray intensity ratios by EDXRF
2013
Abstract In this paper a general method based on energy-dispersive X-ray fluorescence (EDXRF) analysis has been tested to assess its possible use as a tool to reconstruct the structure and determine the thickness of two and/or multi-layered materials. The method utilizes the X-ray intensity ratios of Kα/Kβ or Lα/Lβ peaks (or the ratio of these peaks) for selected elements present in multi-layered objects of various materials (Au alloys, gilded Cu, gilded Ag, gilded Pb, Ag–Au Tumbaga, stone surfaces with protective treatments, Zn or Nickel plating on metals). Results show that, in the case of multi-layered samples, a correct calculation of the peak ratio (Kα /Kβ and/or Lα/Lβ) of relevant ele…