Volumen 22 (2014): Heft 1 (March 2014)

Environmental impacts of oil spills affecting urban sewage networks can be eliminated if timely intervention is taken. The design of such actions requires knowledge of the transport of surface pollutants in open channels. In this study we investigated the travel time and dispersion of pollutants by means of tracer experiments in sewage networks and a creek. The travel time of surface tracers has been found to be significantly shorter than that of a bulk flow tracer. The ratio of the travel times of a bulk flow tracer and surface tracers agreed with the known correlations obtained for rivers. An increasing tendency in the ratio of travel times has been observed for increasing bulk flow velocity. A segment-wise dispersion model was implemented in the existing hydraulic model of a sewer system. The simulation results were compared with the experimental observations. The dispersion rate of the bulk flow tracer has been found to obey Taylor’s mixing theory for long channels and was more intensive than that of surface tracers in community sewage channels.

Flood protection is one of several disciplines where geospatial data is very important and is a crucial component. Its management, processing and sharing form the foundation for their efficient use; therefore, special attention is required in the development of effective, precise, standardized, and interoperable models for the discovery and publishing of data on the Web. This paper describes the design of a methodology to discover Open Geospatial Consortium (OGC) services on the Web and collect descriptive information, i.e., metadata in a geocatalogue. A pilot implementation of the proposed methodology - Geocatalogue of geospatial information provided by OGC services discovered on Google (hereinafter “Geocatalogue”) - was used to search for available resources relevant to the area of flood protection. The result is an analysis of the availability of resources discovered through their metadata collected from the OGC services (WMS, WFS, etc.) and the resources they provide (WMS layers, WFS objects, etc.) within the domain of flood protection.

Let us have two coordinate systems in a plane. In the first one (e.g. JTSK) the accuracy of the coordinate estimators is signicantly lower than the accuracy in the other system (the inner system of an object). The task is to determine the coordinate estimators of the characteristic points of the object in the first system (with a signicantly lower degree of accuracy) in such a way that the relative accuracy of the characteristic points is the same as the relative accuracy in the inner system.

A numerical analysis based on the meshless local Petrov- Galerkin (MLPG) method is proposed for a functionally graded material FGM (FGMfunctionally graded material) beam. The planar bending of the beam is considered with a transversal gradation of Young's modulus and a variable depth of the beam. The collocation formulation is constructed from the equilibrium equations for the mechanical fields. Dirac's delta function is employed as a test function in the derivation of a strong formulation. The Moving Least Squares (MLS) approximation technique is applied for an approximation of the spatial variations of all the physical quantities. An investigation of the accuracy, the convergence of the accuracy, the computational efficiency and the effect of the level of the gradation of Young's modulus on the behaviour of coupled mechanical fields is presented in various boundary value problems for a rectangular beam with a functionally graded Young's modulus.

The aim of the work is oriented towards the simulation or modeling of the lumbar and thoracic human spine as a load-bearing 3D system in a computer program (ANSYS). The human spine model includes a determination of the geometry based on X-ray pictures of frontal and lateral projections. For this reason, another computer code, BMPCOORDINATES, was developed as an aid to obtain the most precise and realistic model of the spine. Various positions, deformations, scoliosis, rotation and torsion can be modelled. Once the geometry is done, external loading on different spinal segments is entered; consequently, the response could be analysed. This can contribute a lot to medical practice as a tool for diagnoses, and developing implants or other artificial instruments for fixing the spine.

The ecological status of a river is influenced by many factors, of which the most important are fauna and flora; in this paper they are defined as a habitat. During the years 2004, 2005, 2006 and 2011, research on the hydroecological quality of a habitat was evaluated in the reference section of the Drietomica River. Drietomica is a typical representative river of the Slovak flysch area and is located in the region of the White Carpathians in the northwestern part of Slovakia. In this article the results of modeling a microhabitat by means of the Instream Flow Incremental Methodology (IFIM) are presented. For the one-dimensional modeling, the River Habitat Simulation System (RHABSIM) was used to analyse the interaction between a water flow, the morphology of a riverbed, and the biological components of the environment. The habitat ´s hydroecological quality was evaluated after detailed ichthyological, topographical and hydro-morphological surveys. The main step was assessing the biotic characteristics of the habitat through the suitability curves for the Brown trout (Salmo trutta m. fario). Suitability curves are a graphic representation of the main biotic and abiotic preferences of a microhabitat´s components. The suitability curves were derived for the depth, velocity, fish covers and degree of the shading. For evaluating the quality of the aquatic habitat, 19 fish covers were closely monitored and evaluated. The results of the Weighted Usable Area (WUA = f (Q)) were evaluated from a comprehensive assessment of the referenced reach of the Drietomica River.