Ground Water Flow Modelling Applications in Mining Hydrogeology

Some specific features and problems of numerical modelling applications in mining environment are briefly discussed and three modelling case studies are presented. Two of the applications are aimed at mine dewatering problems in active coal mines. The first represents the underground hard coal mining region in the Czech part of the Upper Silesian Coal Basin. The second example is focussed on optimisation of the dewatering regime of open pit mining of brown coal in the Most sub-basin of the North Bohemian Coal Basin. The third example describes how mathematical modelling can be applied to solve issues associated with the intensive use of mine waters from the flooded Olsi-Drahonin mine as a source of uranium to shorten the time necessary for the purification of mine waters discharged into watercourses.     

Diffusion of One‐ and Two‐Component Fluids into Polymeric Membranes

The starting point of this paper is a model of the non‐Fickian diffusion of a simple fluid into a polymeric medium that has been introduced in El Afif and Grmela (2002). The model is extended to a mixture consisting of two simple fluids and one polymeric medium. The effects of the polymeric medium on diffusion are included in the formulations through the use of relative momenta playing the role of internal variables. In ternary mixtures, new phenomena arise due to cross‐coupling effects. As a consequence, the single diffusion Deborah number in binary mixtures becomes a 2 × 2 matrix in ternary mixtures. Two specific examples for which experimental data are available are investigated in detail.     

Analysis of color shift on butterfly wings by Fourier transform of images from atomic force microscopy

Butterfly wings have complex structure lending it several interesting properties. Coloration of the wing is one of the first things to encounter and the overall visual effect is in fact influenced by several factors. Chemical pigments set the base color of the wing, topographical structures on the wing scales cause color shift by interference and their arrangement into diffraction grating causes iridescence. The thin film interference can be attributed to microscopic ridges covering wing scales. Observation and calculation of the color shift on wings of Euploea mulciber species using Fourier transform of images obtained by atomic force microscopy is the focus of this article.     

Stereometric Analysis of Effects of Heat Stressing on Micromorphology of Si Single Crystals

Silicon - The purpose of this work is study of silicon single crystal wafer thermal stability in correlation with three-dimensional (3D) surface characterization using atomic force microscopy...     

A theoretical approach to solid filler dispersion in a twin‐screw extruder

Compounding of highly filled minerals in a polymeric matrix has never been an easy task. The objective of this work was to build a theoretical model to predict the evolution of dispersion of an inorganic filler in a polymer matrix along a twin‐screw extruder as a function of the screw geometry and processing conditions. We developed a general kinetic model of agglomeration/breakup of the fillers, based on chemical‐like equations. It allowed us to describe the evolution of a population of agglomerates, taking into account the deformation field. When implemented in a flow model of a twin‐screw extrusion process, the model can be used to pinpoint the main effects of twin‐screw operating conditions on dispersion.     

Rheology of short fiber filled thermoplastics

We examine the applicability of the conformation tensor to describe the fiber orientation and rheology of moderately concentrated fiber-filled thermoplastics subjected to large deformation flow. To retain computational simplicity, we assume a Newtonian matrix. We present a model that can account for orientation effects, Brownian motion, semiflexibility, and interactions through excluded volume effect, of the fibers. The model predicts a wide variety of rheological effects. We present predictions of steady shear viscosity, primary normal stress and the creep functions, as well as uniaxial elongational viscosity, due to the fibers. We have compared rheological data for 9.54 wt% carbon fibers in polyethylene and 30 wt% glass fibers in polypropylene, with the model predictions. By defining an “effective fiber concentration,” we have been able to correlate the model well with data. With fitting parameters from the steady state viscosity vs. shear rate data, we have been able to predict the steady state primary stress coefficient data as well as the creep data.     

Common structure,compatibility and complementarity of mathematical models of injection molding

The hierarchy of mathematical models of injection molding is reviewed. Compatibility of the models of the hierarchy, usefulness of simultaneous applications of models formulated on several different levels of the hierarchy and compatability between physical approximations leading to the formulation of a model, and mathematical approximations used to solve numerically the governing equations of the model are discussed. This review is intended to facilitate the search for a model that is best suited to a given need and to indicate future research.     

Role of thermodynamics in multiscale physics

One way to deal with complexity is to recognize important features, concentrate on them, and ignore everything else. A useful strategy for the recognition process is to carry out the investigation on several levels involving different amounts of detail and then compare the results. The comparison is, in its essence, thermodynamics. We formulate such abstract thermodynamics (we call it the Dynamical Maximum Entropy Principle) and show that the equilibrium and nonequilibrium thermodynamics as well as the equilibrium and nonequilibrium statistical mechanics are all its particular representations.