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  • Author: Peter Halaj x
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Sensitivity Analysis of Input Data in Surface Water Quality Models

Abstract

The article is focused on analysis of input data impact on outputs of water quality models. The authors examined the impact of roughness coefficient, both boundary and initial conditions setup on changes of outputs generated by HEC-RAS model. Simulation results have shown a various response rate of input data on simulated results. The strong impact shows roughness coefficient setup that through the value of longitudinal dispersion coefficient affects pollution transport process. Changes in boundary conditions have had less influence on outputs. Relatively strong impact shows the setup of initial state of pollution concentration along the reach mainly for the case of low gradient rivers.

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Water Management for Sustainable Growth Strategies

Abstract

The aim of this document is to present a synthesis of water sustainability issues as the basic role in the sustainable growth strategies in many countries. Water crisis and extreme weather conditions have been identified by the World Economic Forum community as two of the top ten global risks. This is hardly surprising, considering the devastating impacts of having too little water, or too much. While water’s immediate impacts are often local, water security is now recognized as the systemic global risk. Each development has its own limiting parameters. In the latest decades, we have recognized the term ‚blue and green water‘. Blue water availability is a limiting factor for the green water. Due to the changes and processes in the country, as climatic, economic or socio-economic ones, fundamental factor for sustainable development is to secure water supply. Soil water and its availability for crop production during the growing season appear to be a problem. Surface water resources created for the additional irrigation in the pastures are now used for other purposes such as energy or industry. It is therefore important for water sustainability in the countries to increase the water resources protection.

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Small Sacral Architecture and Its Greenery in Lower Spiš Region in Slovakia

Abstract

Small sacral structures are significant elements of Spiš cultural landscapes (North-East Slovakia). This paper presents results of the field mapping of small roadside sacral objects and their greenery along a 66-kilometre long road section connecting North and South of Lower Spiš and the municipalities of Levoča, Spišská Nová Ves, Hnilčík, Mníšek nad Hnilcom, Smolník, and Úhorná. This road was an old trade route and has an important historical legacy in Lower Spiš – a traditional mining cultural landscape with a characteristic hilly topography, wide forest landscapes and rich mining history. The presented mapping was conducted within the research project VEGA 1/0371/18 “SacralArch: Preservation of the Historical Legacy and Architectural Diversity of Small Sacral Structures in Cultural Landscapes of Slovakia“, based on the methodology elaborated by Tóth (2018), which includes localisation, spatial context, technical or health condition and an overall description of the sacral element and the woody plants in its direct surroundings. In total, 13 small roadside sacral objects were mapped, while the most prevailing elements are crosses. The most common cross type is wooden cross without pedestal. The oldest and aesthetically most valuable elements are metal crosses on stone pedestals, made of travertine. The most valuable element is a registered cultural monument – a Baroque roadside chapel of St. John of Nepomuk from 1726 in Smolník. Woody plants accompany only roadside crosses in the study area. The oldest and most significant in terms of landscape value are individuals of small-leaved linden trees (Tilia cordata Mill).

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Pollution Spread Analysis In The Malá Nitra River By Using Of 1-D Model

Abstract

The Water Framework Directive (WFD) is a key initiative aimed at improving water quality throughout the EU. The development of the computer technologies enables us to solve the ecological problems in water management practice very efficiently. The mathematical and numerical modelling allows evaluating various situations of contaminants spread in rivers (from everyday wastewater disposal through the fatal discharges of toxic substances) without immediate destructive impact on the environment. The paper deals with 1-dimensional numerical model HEC-RAS and its response on various values of dispersion coefficient. This parameter is one of the most important input data for simulation of pollution spread in streams. There were performed tracer experiments in the Malá Nitra River and results of these measurements are compared with results of numerical simulations. The values of the longitudinal dispersion coefficient were estimated from this comparison. The range of mean values of this coefficient determined on the base of numerical model application was 0.05 – 0.13 m2 s−1, for the other flow condition it was 0.07 – 2.5 m2 s−1 or 0.28 – 0.6 m2 s−1. The next task was carrying out the model sensitivity analysis, which means to evaluate input data influences, especially longitudinal dispersion coefficient, on outputs computed by 1-dimensional simulation model HEC-RAS. According to the results it can be said that the model HEC-RAS responds to longitudinal dispersion coefficient value changes adequately, suitably and proportionately. The application of the model HEC-RAS demonstrated the eligibility for simulation of pollution spread in streams, which means that it is a suitable tool allowing a reasonable support in decision making process connected to river water quality management.

Open access
Importance of Performing Experience in Strength Training Periodization

Summary

Proper mastering of a training means seems to be an important determinant of the quality of strength training. Aim of the paper is to examine the differences in strength in relation to squat-performing experience and to offer a way of improving performance by means of increasing the quality of squat technique. Methods 1. Subjects were divided into two groups according to their previous experience with performing squat: a group of inexperienced (n = 9; age: 21.1 years ± 2.37; height: 179.2 cm ± 8.18; weight: 70.0 kg ± 7.38) and experienced (n = 9; age: 24.0 years ± 1.07; height: 182.1 cm ± 4.14; weight: 81.2 kg ± 4.29). We carried out a test of maximal isometric strength in deep squat (ISOmax50°) and a modified diagnostic set (Fitro Force Plate) which consisted of repetitions of heel raised deep squats with a gradually increasing external loading (FmaxBW+(0-100%)). Posture and the body segments of the participants were not corrected during these tests. Mann-Whitney U test (α=0.05) was used to evaluate the data obtained. Results 1. After comparing the differences in the maximal value of force curve in dynamic muscular mode (FmaxBW+(0-100%)) and the maximal isometric force in deep squat (ISOmax50°) between the groups we found significantly bigger differences in the group of experienced when the resistance represented +75 % (Δ 279.0 N) and +100 % of body weight (Δ 332.2 N). Methods 2. Eleven inexperienced subjects (age: 22.1 years ± 1.52; weight: 78.2 kg ± 2.84) completed a short term experiment (with 4 training sessions in weeklong microcycle). The purpose was to practise deep squat without any content of targeted strength development.

No control group was included. Initial and final measurements included the rate of force development test (RFD50°,90°,140°, 0-200 ms), the maximal isometric strength test (ISOmax50°,90°,140°) and the diagnostic set for deep squat (Fitro Dyne Premium). Wilcoxon T-test was used for further analyses (α = 0.01; α = 0.05). Results 2. We found statistically significant increments of ISOmax50° (Δ 89.45 N, p < 0.01), ISOmax90° (Δ 45.63 N, p < 0.05), RFD50°(0-200ms) (Δ 0.42 N.ms-1, p < 0.05), RFD90°(0-200ms) (Δ 0.47 N.ms-1, p < 0.05) and mean power output (Pmean) of entire diagnostic set (Δ 38.8 W, p < 0.01). Conclusions. Increases in the difference in variations between the groups starting from the resistance of 50 % of body weight confirms the recommendations of using lower weights for beginners for the purpose of strength development. Based on the results we conclude that a short-term training programme of deep squat practise (without any intention of improving strength performance) has positive effect on selected strength parameters.

Open access
Influence of discharge on fish habitat suitability curves in mountain watercourses in IFIM methodology

Abstract

In this study, the quality of the aquatic habitats of mountain and piedmont streams was evaluated using the ‘Instream Flow Incremental Methodology (IFIM)’ decision-making tool. The quality of habitats was interpreted from the behaviour of bioindicators in the form of habitat suitability curves (HSCs). From 1995 until the present, 59 different reaches of 43 mountain streams in Slovakia and 3 validation reaches were evaluated, and the results analysed. The aim of this study was to generalize the parameters of the HSCs for the brown trout. The generalized curves will be useful for water management planning. It is difficult and time-consuming to take hydrometrical and ichthyological measurements at different water levels. Therefore, we developed a methodology for modifying suitability curves based on an ichthyological survey during a low flow and a flow at which fish lose the ability to resist the flow velocity. The study provides the information how such curves can be modified for a wider flow range. In summary, this study shows that generalized HSCs provide representative data that can be used to support both the design of river restoration and the assessment of the impacts of the water use or of climate change on stream habitat quality.

Open access
Application of Monte Carlo Method for Evaluation of Uncertainties of ITS-90 by Standard Platinum Resistance Thermometer

Abstract

Evaluation of uncertainties of the temperature measurement by standard platinum resistance thermometer calibrated at the defining fixed points according to ITS-90 is a problem that can be solved in different ways. The paper presents a procedure based on the propagation of distributions using the Monte Carlo method. The procedure employs generation of pseudo-random numbers for the input variables of resistances at the defining fixed points, supposing the multivariate Gaussian distribution for input quantities. This allows taking into account the correlations among resistances at the defining fixed points. Assumption of Gaussian probability density function is acceptable, with respect to the several sources of uncertainties of resistances. In the case of uncorrelated resistances at the defining fixed points, the method is applicable to any probability density function. Validation of the law of propagation of uncertainty using the Monte Carlo method is presented on the example of specific data for 25 Ω standard platinum resistance thermometer in the temperature range from 0 to 660 °C. Using this example, we demonstrate suitability of the method by validation of its results.

Open access