On the relationship between refractive index and density for SiO2 polymorphs

The Gladstone-Dale law (specific refraction) and the Drude law (molecular refraction) for silica polymorphs, at “sodium light” (λ _D =0.5893 μm), are derived from simple atomic properties of SiO₂ complex (atomic weight, first ionization potential). The considerations are based on the Lorentz electron theory of solids. The characteristic frequency (or eigenfrequency) v ₀ of elementary electron oscillators (in energy units, hv) is identified with the band gap E _G of a solid; on the other hand, this E _G -gap is identified with the single ionization potential \(\tilde U\) of non-free atoms. For \(\tilde U\) =E _G =10.2 eV (energy gap of quartz, see Nitsan and Shankland 1976b) the Gladstone-Dale law, or specific refraction, is (n?1)/ρ=0.208 cm³/g, where n and ρ are the refractive index and the density of medium, respectively. According to empirical data, the average value of the specific refraction of pure SiO₂ polymorphs (except stishovite-high density phase of silica) is (〈n〉?1)/ρ=0.207±0.001 (〈n〉 denotes the mean refractive index of crystal). For stishovite the Drude law (n ²?1)/ρ=0.542 cm³/g is valid under an assumption that the first ionization potential \(\tilde U\) =E _G ≈9 eV; this result is good agreement with the empirical value (〈n〉²?1)/ρ=0.536 cm³/g.     

Problems of migration of Polish crude oils on the basis of geochemical correlation data and carbon isotope composition

A method for the correlation of crude oils has been worked out on the basis of analyses of 120 crude oils from 4 geological regions of Poland.     

Mortar Upscaling for Multiphase Flow in Porous Media

In mortar space upscaling methods, a reservoir is decomposed into a series of subdomains (blocks) in which independently constructed numerical grids and possibly different physical models and discretization techniques can be employed in each block. Physically meaningful matching conditions are imposed on block interfaces in a numerically stable and accurate way using mortar finite element spaces. Coarse mortar grids and fine subdomain grids provide two-scale approximations. In the resulting effective solution flow is computed in subdomains on the fine scale while fluxes are matched on the coarse scale. In addition the flexibility to vary adaptively the number of interface degrees of freedom leads to more accurate multiscale approximations. This methodology has been implemented in the Center for Subsurface Modeling's multiphysics multiblock simulator IPARS (Integrated Parallel Accurate reservoir Simulator). Computational experiments demonstrate that this approach is scalable in parallel and it can be applied to non-matching grids across the interface, multinumerics and multiphysics models, and mortar adaptivity. Moreover unlike most upscaling approaches the underlying systems can be treated fully implicitly.     

Normal form,Lie-Poisson structure and reduction for the Henon-Heiles system

The reduced Henon-Heiles system is investigated as a Hamiltonian dynamical system obtained by applying the normalization of the HamiltonianH=1/2(p ₁ ² +p ₂ ² +q ₁ ² +q ₂ ² )+1/3q ₁ ³ –q ₁ q ₂ ² to fourth-degree terms. The related equations of motion are bi-Hamiltonian and possess the Lie-Poisson structure. Each Lie-Poisson structure possesses an associated Casimir function. When reduced to level sets of these functions, the equations of motion take various symplectic forms. The various reductions give different coordinate representations of the solutions. These coordinate representations are used to seek the simplest representation of the solutions.     

Effects of rainy season on mobilization of contaminants from tsunami deposits left in a coastal zone of Thailand by the 26 December 2004 tsunami

Study on contamination of tsunami sediments deposited on 26 December 2004 conducted shortly after the tsunami in coastal zone of Thailand revealed elevated contents of salts in water-soluble and some heavy metals and arsenic in bioavailable fractions (Szczuciński et al. in Env Geol 49:321–331, 2005). Few months later rainy season started and effected in total rainfall of over 3,300 mm. This paper presents results of survey repeated 1 year after the tsunami. To assess the effects of rainy season on mobilization of previously determined potential contaminants, the same locations were sampled again and analysed with the same methods. The tsunami deposit layer was well preserved but in many locations the sediments were coarser than just after tsunami due to washing out of finer fractions. The water-soluble salts contents were strongly reduced after the rainy season. However, the concentrations of acid leachable heavy metals and metalloids were still elevated in comparison to reference sample from an area not impacted by tsunami. It is possible that the metals and metalloids are successively moved to more bioavailable fraction from forms which were more resistant to mobilization.     

Archaeological objects in loesses recognized by GPR research at the site Karmanowice,Poland

The aim of the research was to examine subsurface soil layers with the use of the Ground Penetrating Radar (GPR) method. Neolithic archaeological post in Karmanowice was examined. On the basis of earlier geophysical researches and archaeological premises, eight measurement profiles had been chosen. Ground Penetrating Radar system with antenna of 500 MHz frequency was applied. The measurements were made with 30 and 60 ns time windows. The results were shown as the GPR sections. The analysis of the obtained results allowed us to outline anomalies connected with the appearance of archaeological objects in subsurface soil layers. The border between the anthropogenically changed upper layer and undisturbed loess was established, and the sections of slope wash layers were designated. Anomalies were confirmed by digging and test drillings. Additionally, 2D resistivity imaging method was used for verification of specific anthropogenic anomalies.     

Wavefield downward extrapolation for migration velocity analysis on Marmousi data-set

The authors present a method for estimation of interval velocities using the downward continuation of the wavefield to perform layer-stripping migration velocity analysis. The generalized, phase-shift migration MG(F-K) in wavenumber-frequency domain was used for fulltime downward extrapolation of the wavefield. Such downward depth extrapolation accounts for strong changes of velocity in lateral and vertical directions and helps in correct positioning of the wavefield image in complex structures. Determination of velocity is the recursive process which means that the wavefield on depth level z _n−1 (n = 0, 1, ...) is an input data-set for determination of velocity on level z _n . The velocity ν [x, z _n − z _n−1] can be thus treated as interval velocity in Δz _n = z _n − z _n−1 step. This method was tested on synthetic Marmousi data-set and showed satisfactory results for complex, inhomogeneous media.     

A review of geochemical background concepts and an example using data from Poland

One of the most crucial issues of recent environmental sciences is the topic of background concentrations of elements and organic compounds in various abiotic and biotic systems. The relationship between natural and anthropogenically altered concentrations of chemical species is a question that involves many implications in the geosciences, environmental and biological sciences, toxicology, and other related disciplines. This is especially important when interpreting geochemical and biogeochemical anomalies of toxic elements and/or organic compounds in various media. To better understand the potential impact of hazardous substances in the environment, we must become more familiar with their spatial and temporal distribution and with their behavior under different physico-chemical and biotic conditions. This review presents an assessment of the geochemical background concept as used by various authors. Different assumptions and approaches to this topic are presented, including direct, statistical, and integrated methods. Based on the results derived from geochemical and biogeochemical studies performed in selected forest ecosystems of Poland, an integrated method is presented. As a consequence of data processing, a normal distribution of data points was obtained using an iterative 2σ-technique. This method of estimating geochemical background is feasible and can be used for setting environmental quality standards or for studying the impact of anthropogenic pollution sources on the environment.