Heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in soils and plants of four different ecosystems (forest, grassland, agro and urban ecosystem) at different distances from the source of the pollution were analyzed in order to assess and compare soil contamination in the various ecosystems and determine the potential accumulation of plants depending on the place they inhabit. Correlation relationships among heavy metals in soils differ depending on the ecosystem, and between soil and plant, the heavy metals showed significant correlation for Cu, Mn, Ni, Pb and Zn. Contamination factor (C), degree of contamination (C) and pollution load index (PLI) were used in order to determine the level of environmental contamination of the study area. All studied ecosystems were rated as moderately contaminated (except agroecosystem, which was found as low contamination ecosystem) according to C and extremely polluted according to PLI. The highest pollution in both cases was found in urban ecosystem, and Cd, Cu and Fe were determined as the biggest pollutants.
Considering the global tendency in water saving, this research is focused on practical measurements of even distribution of water. The performance quality is determined by values of coefficients of distribution uniformity and non-uniformity given in percentages. Objects of investigation were belt irrigators with varying input conditions (seven pieces). Testing of hose-reel irrigators took place in Southern and Western Slovakia. Tests were carried out during irrigation of selected agricultural crops (potatoes, vegetables); in these areas, rainwater vessels were distributed at a spacing of 1 or 2 m, perpendicular to the direction of movement of the bracket or tripod with a gun sprinkler. The input conditions, such as machine specifications and weather conditions, were monitored and evaluated for all variants. The data were also analysed along with the linear model through statistical analysis software – one-way analysis of variance ANOVA. Considering the results, it is possible to conclude that there were recorded statistically significant differences for uniformity coefficients, depending not only on the site but also on the specific evaluation methodology (P > 0.05). If the input conditions (site, type of irrigator, sprinkler) were changed, the effect of dependence was demonstrated to a much greater extent (P <0.05, F = 7.08> Fcrit). The results of the non-uniformity coefficients confirmed the statistically significant differences not only in the sample sets of coefficients but also in the selection sets of conditions.
The study deals with the use of energy crops for the production of thermal energy in the form of briquettes and devising appropriate parameters for their production. Briquettes were produced from seven kinds of energy crops, Salix viminalis, Miscanthus sinensis, Rosa multiflora, Polygonum sachalinensis, Helianthus tuberosus, Sida hermaphrodita and Spartina pectinata, specifically. In the production of briquettes, moisture is the most important properties of material to be pressed, which ranges from 8 to 15 % as it was observed. At a higher humidity it has not been possible to produce briquettes farther in the study conditions. Another important condition for the successful production of briquettes was the particle size of chopped mass. The optimum particle size range from 8 to 20 %. The briquettes were pressed at a pressure of 21 MPa and with diameter of 50 %. Subsequently, physical and mechanical properties (density, moisture, mechanical resistance) and chemical properties (chlorine, iron, nitrogen, calcium, ash, lignin content) were measured. The briquettes density reached from 800 to 900 kg.m−3 with calorific value from 14 to 19 MJ.kg−1 which refers to fact that energy crops are competitive to fossil fuels by their calorific value.
The aim of this paper was a monitoring of harvest process of wood material. Measurement of energy potential during burning process was realized with wood chips. Wood chips contained 20% of moisture. During this experiment we detected an influence of wood chips moisture content on CO, CO 2 , NO production and NO 2 emission gases production. All measured emissions values were within the normative range defined by Decree 356/2010 Coll of the Ministry of Agriculture, Environment and Regional Development of the Slovak Republic.
During the cultivation of crops, irrigation is included in necessary working operations like tillage, fertilization and sowing. For irrigation, we require the highest quality of work. Therefore, in this contribution, we focused on monitoring the quality of work of a hose reel irrigation machine. For determining the longitudinal uniformity of winding a hose on a reel, the development of a digital device was necessary. During the development, we had to design its two basic parts-the hardware and software. After construction of the device, its function was tested directly in working conditions of the particular reel hose irrigation machine. The results of our developed device were compared with the results of the Ecostar 4000 (Bauer, Austria) microcomputer, both with the same hose winding speed. On the microcomputer, we set the hose winding speed to +2.1 m*h-1. The average measured value of speed using the first device Speedmeter SM1 (2000, KSVS) was 11.7 m*h-1. The difference between the set and measured speed was 0.4 m*h-1 (absolute error of measurement, the relative error of measurement was 3.42 %). In the second case, the measurement was performed using a more modern device-Speedmeter SM2, which allows saving of results into its internal memory (2012, KSVS). The average measured value of winding speed was 12.26 m*h-1 , which represents the relative error of measurement 2.77 % compared to the set value of 12.6 m*h-1. Based on the results obtained, we recommend the maintenance of the irrigation machine.
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