Foam Concrete as New Material in Road Constructions

Foamed Concrete Layer as Sub-structure of Industrial Concrete Floor

Coal-waste dumps are an integral part of the environment and shape the landscape of coal basins. This study aimed to present an analysis of environmental changes in terms of land use and changes in vegetation on self-heating coal-waste dumps of different ages. Spatial and temporal analyses of land relief and land cover in the area of the investigated coal-waste dumps were performed. The investigated areas differed in size, shape, management, and land cover. Thermally active zones were identified. The results showed that the species composition of the flora is diverse, but representatives of the Asteraceae family dominate on both dumps. The diversity of flora in the investigated dumps depends on the presence of mosaic- and microhabitats (often of an extreme nature) and the nature of the vegetation in the surroundings, which is manifested by the participation of socioecological groups of flora. The pace and dynamics of succession on burning coal-waste dumps depends on the stage of the fire, the topography, and the nature of the substrate. The investigated changes in the elements of the environment are important from the point of view of application research and monitoring of postindustrial areas, which may allow for the optimal management of postmining dumps.

Environmental Management and Landscape Transformation on Self-Heating Coal-Waste Dumps in the Upper Silesian Coal Basin

We investigate a novel method for the numerical solution of two-dimensional time-dependent convection–diffusion–reaction equations with nonhomogeneous boundary conditions. We first approximate the equation in space by a stable Gaussian radial basis function (RBF) method and obtain a matrix system of ODEs. The advantage of our method is that, by avoiding Kronecker products, this system can be solved using one of the standard methods for ODEs. For the linear case, we show that the matrix system of ODEs becomes a Sylvester-type equation, and for the nonlinear case we solve it using predictor–corrector schemes such as Adams–Bashforth and implicit–explicit (IMEX) methods. This work is based on the idea proposed in our previous paper (2016), in which we enhanced the expansion approach based on Hermite polynomials for evaluating Gaussian radial basis function interpolants. In the present paper the eigenfunction expansions are rebuilt based on Chebyshev polynomials which are more suitable in numerical computations. The accuracy, robustness and computational efficiency of the method are presented by numerically solving several problems.

A stable Gaussian radial basis function method for solving nonlinear unsteady convection–diffusion–reaction equations

This paper presents an overview of the singular boundary method (SBM) and its various engineering applications. The basic concepts of the singular boundary method are first introduced, such as the collocation scheme, fundamental solutions and origin intensity factors (OIFs). In the SBM implementation, the OIF-determination approaches are then classified into three categories, namely, the inverse interpolation technique (IIT), the subtracting and adding-back technique (SABT) and the integral mean value (IMV). Several additional schemes are introduced to resolve the non-uniqueness issue encountered in the SBM, and enable the application of the SBM to large-scale engineering and scientific computing, nonhomogeneous partial differential equations (PDEs), non-isotropic problems and initial-boundary value problems. Several selected numerical examples are presented and discussed to show the recent developments and applications of the SBM to the solution of some typical boundary value problems, such as anomalous heat conduction, high wavenumber acoustic wave propagation, water wave-structure interaction, elastic wave propagation and structural vibration induced underwater acoustic radiation in the shallow ocean environment and so on. Besides, some efficient techniques, such as moment condition and modified combined Helmholtz integral equation formulation (CHIEF), are introduced into the SBM to enhance its performance. Finally, the essential conclusions of the SBM are summarized and some future trends in this interesting research field are highlighted. 

Singular boundary method: A review and computer implementation aspects

Analysis of Possibilities of Reclamation Waste Dumps after Coal Mining

In this paper, a meshless numerical algorithm is developed for the solution of two-dimensional diffusion equations with different boundary conditions. The proposed numerical method, which is truly meshless and quadrature-free, is based on the time-marching finite difference scheme, the method of the particular solutions and the singular boundary method. The diffusion equation is transformed into a Poisson-type or a modified Helmholtz equation after the time domain is discretized by the Euler or Houbolt finite difference scheme.

Singular boundary method using dual reciprocity for two-dimensional transient diffusion

This paper focuses on deriving a local variant of a singular boundary method for steady and unsteady potential flow. Compared to the global variant, local leads to the sparse resulting matrix of the system of equations and thus makes the solution of large-scale tasks more effective. The combination of the singular boundary method and the finite collocation method were used for localization. The article compares the results of global and local variation on several examples for both steady and unsteady flow, and the dependence of the solution precision on the density of the nodal network and the dimensions of the stencil was also studied.

Local singular boundary method for two-dimensional steady and unsteady potential flow

Abstract The geotechnical monitoring of the slope deformations is widespread at present time. In many geological localities and civil engineering construction areas, monitoring is a unique tool for controlling of negative factors and processes, also inform us about actual state of rock environment or interacting structures. It is necessary for risk assessment. In our case, geotechnical monitoring is controlling rockslide activity around in the future part of motorway. The construction of new highway route D1 from Bratislava to Košice crosses the territory which is affected by a massive rockslide close to Kraľovany village. There was a need to monitor the activity of a large unstable rockslide with deep shear planes. In this case of underground movement activity, the Department of Geotechnics of the University of Žilina installed inclinometers at the unstable area which worked on Time Domain Reflectometry (TDR) principle. Based on provided measurements, effectivity and suitability of TDR inclinometers for monitoring of deep underground movement activity is demonstrated.

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Rock Slide Monitoring by Using TDR Inclinometers

The paper deals with use of the meshless method for slope stability analysis. There are many formulations of the meshless methods. The article presents the Meshless Local Petrov-Galerkin method (MLPG) – local weak formulation of the equilibrium equations. The main difference between meshless methods and the conventional finite element method (FEM) is that meshless shape functions are constructed using randomly scattered set of points without any relation between points. The shape function construction is the crucial part of the meshless numerical analysis. The numerical example of the slope stability was calculated using meshless computer code and compared with FEM and limit equilibrium (LEM) results.

Roman Bulko

Papers

Analysis of Possibilities of Reclamation Waste Dumps after Coal Mining

Singular boundary method using dual reciprocity for two-dimensional transient diffusion

Local singular boundary method for two-dimensional steady and unsteady potential flow

Rock Slide Monitoring by Using TDR Inclinometers

The Slope Stability Solution Using Meshless Local Petrov-Galerkin Method