Vlasta Ondrejka Harbuľáková

Using of Multicriteria Method for Choosing the Best Alternative of the Heating Power Plant

Abstract The paper presents construction of heating system in Trebišov town in alternative solution and its environmental impact assessment (EIA). Choosing the best alternative consider zero variant (if no activity is done - present state of the environment) and another two alternatives assessment using the method of the total indicator of environmental quality. Nine selected criteria were divided into four groups according to their character - economic, technical, ecological and social. Based on evaluation of the construction of biomass-fired power plant seems to be the best solution of heating system for Trebišov town.

Flood Risk Assessment from Flash Floods in Bodva River Basin, Slovakia

The main objective of flood management as well as the entire management cycle is regulated by Directive of the European Parliament and of the Council 2007/60/EC on the assessment and management of flood risks. The paper deals with an application of preliminary flood risk assessment, particularly flood risk assessment from flash floods in the Bodva river basin, which is situated in the south of the Slovak Republic. The aim of the preliminary assessment of flood risk from flash floods is determining the hazard and the vulnerability of assessed area. The result of identification of a hazard is the determination of critical points in the basin and their contributing surfaces on the basis of the geometric and physiogeographic characteristics of the contributing surfaces. Vulnerability in the study area is determined on the basis of the type and density of the built-up area. The resulting flood risk is stated as a moderate risk. The scope and extremity of flood episodes point to the need to build a comprehensive system of flood protection measures in potential flood areas.

Study of Dependencies Between Concrete Deterioration Parameters of Fly Ash-Based Specimens

Corrosion of concrete can lead to reduction of engineering properties such as strength, elastic modulus and durability and it may happen due to a number of various physical, chemical, and physic-chemical factors and their interactions reflecting peculiarities of both material aspects and external factors. In the paper, investigation of concrete specimens where the fly ash replacement was 10 wt% of cement content and they were exposed to aggressive environment of aluminium sulphate during the five 7-day cycles is presented. The leached-out masses of the Ca, Si, Fe, Al, Mn, and Cu, measured at the end of each cycle as well as pH values measured during different time period are published. Paper deals with the possibilities of investigation of deterioration parameters (chemical elements concentration, pH) of fly ash-based concrete specimens by correlation analysis. The correlation analysis confirmed the different leaching rate of calcium and silicon. However, the high mutual correlation was found between leaching of the silicon, iron, cuprum, aluminium and manganese.

Determination of pollutant concentrations in the Krasny Brod River profile based on the Buckingham theorem

AbstractThe paper deals with an application of the model which determines concentrations of pollutants in a water stream and which is developed based on dimensional analysis. The most important part is the selection of appropriate variables for model development. The use of dimensional analysis, the Buckingham theorem, for water quality modeling is a new approach. This method could be used for prediction of any pollutant in a water stream. The obtained results demonstrate that dimensional analysis and use of the π theorem is an appropriate approach to water quality modeling. The model presented in the article has universal validity for pollutants in streams that are characterized by at least approximate geometric characteristics. But for each pollutant (and particular stream of course), the parameters of linear function, i.e. regression coefficients, have to be determined separately. The differences between the concentrations calculated from the developed model and actually measured concentrations are als...

Bio-Corrosion of Fibrous Cement Boards and Cement Composites

The paper deals with the comparative study of bio-corrosion of fibrous cement boards and Portland cement composites. Fibre-cement flat boards are widely used materials in the Slovak Republic for exterior and interior cladding, as fibre-cement slates for roofing and cladding and as fibre-cement corrugated sheets for roofing and cladding. Bio-corrosion of studied materials has been simulated in laboratory conditions during 80 days. Effect of sulphur-oxidizing bacteria Acidithiobacillusthiooxidans on the specimens was investigated. The bio-deterioration processes have been manifested by leaching of main cement components as well as by surface changes. The calcium and silicon contents in leachates were evaluated during the experiments using X – ray fluorescence method (XRF). Concluding the results of the concrete’s biodeteriogens influence on the analyzed samples (fiber boards and cement composites) more extensive leaching of calcium ions from the cement matrix was confirmed as assumed by bacteria influence when compared to the abiotic environment. Mixture of white compounds on the samples surface was identified by SEM microscopy and XRD analysis as sulphate products (ettringite, thaumasite, gypsum). Shift of pH of liquid media to alkaline region up to 7.2 due to alkaline products leaching were noticed for all studied samples.