National Repository of Grey Literature 6 records found  Search took 0.00 seconds. 
Influence of sorbents on retention curve of contaminated fluvisol
Hnatajková, Eva ; Jačka, Lukáš (advisor) ; Pavlásek, Jiří (referee)
The thesis deals with the influence of sorbents on the retention curve of the contaminated alluvial soil (fluvisol). The retention curves of soil without sorbents (reference soil) are compared with the soils enriched by the following sorbents. Biochar (BC), amorphous manganese oxide (AMO) and combination of (AMO + BC). Soils sample were collected is specific uncultivated area in the valley of Litavka river (located in the central part of the Czech republic). Two different types of samples were used for measurement of retention curves. First type of the samples were collected from the column experiments and second type were the samples collected in the field. All samples were extracted using in Kopecky rings (100 cm3). The measurement of the retention curves was performed by a direct method in the laboratory. For laboratory determination of the retention curves classical set of instruments were used (sandbox, sand-kaolin box and pressure apparatuses). The measured data were fitted using van Genuchten. Values compared are the bulk density, parameters of van Genuchten model (Thétas, ThétaR, Alfa, n), and values pF (0; 1.0; 2.0; 2.7; 3.0; 3.7; 4.18). The comparison of retention curves of differently treated soil was based on the average, standard deviation and the difference and ratio of the avarages. According to presented findings sorbents affected shapes of the retention curves. Especially biochar influence water content for high pF values. We confirmed the hypothesis according to VERHEIJEN et al. (2010), that biochar tincrase the total retention of soil water, but does not increase the amoust of water avaible plants. The influence of AMO on retention curve was negligible. Therefore sorbent AMO has a small influence on change of water retention in the tested soil. The effect of combined sorbent (AMO + BC) on the retention more significant than effect of using AMO sorbent only. This combination of sorbents affects the water retention depending on applied pF.
Influence of biochar on saturated hydraulic conductivity of contaminated fluvisol
Tomáš, Tomáš ; Jačka, Lukáš (advisor) ; Pavlásek, Jiří (referee)
This thesis deals with the influence of biochar on saturated hydraulic conductivity (Ks) of contaminated fluvisol. Values of Ks are key inputs for modeling of water flow in soils. Contaminated fluvisol and this soil enriched by 2 and also 5% of biochar were studied in this thesis. These differently treated soils ware gauged to find out differences in Ks and changes of Ks time. Biochar improves sorption capacity and other soil properties. The influence of biochar application on Ks it not fully revealed. We used biochar which was made by pyrolysis of stalks of grapevine. Measurements were made in two series since October to December in 2015. For both series, 10 samples, (5 in reference and 5 enriched by biochar) were measured. A total of 20 samples were measured in each series. Every sample was measured for 14 days in 10 time steps (10 recurrent measurements). Physical properties (bulk density, porosity, saturated water content) and particle size analysis using hydrometer method were also measured. Homogeneous soil mixtures of the soils were packed in Kopeckého sampling rings (100 cm3). In first series, 5 reference samples and 5 samples with 2% content of biochar were compared. Saturation of the samples was made gradually and slowly and takes 1 week. Measurement was made by laboratory permeameter (hydraulic gradient about 0.5). For reference samples of first series, mean Ks value was 4,818.10-6 m.s-1. For samples enriched by 5% biochar mean Ks value was 2,254.10-6 m.s-1. For reference of second series, mean Ks value was 6,435.10-6 m.s-1. For samples enriched by 2% biochar mean Ks value was 4,211.10-6 m.s-1. Application of biochar on tested soil decrease Ks in comparison with reference soil. Decrease of Ks value was more distinct for soil enriched 5% of biochar than for soil enriched by 2% of biochar. Application of biochar also decrease coefficient of variation of measured Ks. in most of the time steps. Reference samples exhibited larger differences of Ks among time steps than biochar enriched soils.
Changes of saturated hydraulic conductivity values of soils with different percetnages of biochar during recurrent laboratory measurements
Bočinský, Pavel ; Jačka, Lukáš (advisor) ; Pavlásek, Jiří (referee)
Abstract This thesis deal with the influence of biochar on the saturated hydraulic conductivity (Ks) and time changes of Ks during the recurrent of measurement procedure. Representative values of Ks are crucial for description and modeling of the water low in the soil. Samples used in this thesis represent laboratory-prepared soil (fluvial soil fine grained soil with the addition of 20% kaolin clay). This soil has been enriched by 0, 2 and 5% of biochar. For these different materials, values of Ks and its time changes were determined values using recurrent laboratory measurements. Biochar (material used for improvement of sorption capacity and other soil properties) was made by pyrolysis of grape stalk. Measurements were performed in two series, in January and February 2016. Every series contains ten samples, therefore, twenty samples in two series were measured. Samples were poured into Kopeckeho sampling rings (100cm3). First series contains five samples of fine soil, each sample with 5% addition of biochar to reference soil; the remaining five samples contain reference soil (fluvial soil with 20% addition of clay). Second series contains five samples of fine soil, each sample with 2 % addition of biochar to reference soil; the remaining five samples contain reference soil. Saturation of samples was done gradually by a regulator of laboratory permeameter. Samples were measured using the laboratory permeameter by constant head method. Average values of Ks for samples without biochar (first series), were in range from 1,00.10-7 until do 3,53.10-7 m.s-1. Average values of Ks for 5% biochar, were in range from 6,49.10-8 until 9,20.10-8 m.s-1. For the first series, the mean Ks values of the samples with the 5% biochar addition were every time distinctly lower than mean Ks values for the reference soil. Average values of Ks for samples without biochar (second series), were in range from 1,21.10-7 until 1,84.10-7 m.s-1. Average values of Ks for 2% biochar, were in range from 9,78.10-8 until 1,64.10-7 m.s-1.
Evaluation of extreme discharges on the Jihlava River
Šoukalová, Adéla ; Pavlásek, Jiří (advisor) ; Jačka, Lukáš (referee)
The bachelor thesis deals with the evaluation of extreme discharges at selected hydrometric stations on the Jihlava river between 1997 and 2015. The first part presents the results of the research, characteizing the factors influencing the origin and the course of floods and droughts, providing the description and classification of floods, and consequently giving a general description of the area. Furthermore, the present thesis scrutinizes the flow data acquired from the Morava River state enterprise, calculating individual characteristics. The result of the work is graphs of the flood situation and minimum flow situations, as well as tables providing the calculated characteristics.
Climate of the foothills of Krkonoše mountains according to archival sources
Přívratská, Jana ; Soukupová, Jana (advisor) ; Jačka, Lukáš (referee)
The Bachelors thesis Climate of the foothills of Krkonoše mountains according to archival sources is concerned with the study of climate in the northern lower part of The Giant Mountains, it describes important climatic events of this part and focuses particularly on extreme weather changes including atmospheric events. The information provided in this work is predominantly gained from historic sources and meteorological yearbooks. The main focus is on two periods. It briefly describes the period before the Second World War From whitch exist only a few resource, and in much greater detail the period of the years 1945-1995. The purpose of this Bachelors thesis, based on examined data and figures, is to generally summarize climate and development of the northern lower part of The Giant Mountains. The work might be later used as one of the many bases for another examination of the influence of. And then you can add touristic manual and books about region.
The impact of small water reservoir on soil moisture in Litovicko-Šárecký brook basin
Kovář, Martin ; Hradilek, Václav (advisor) ; Jačka, Lukáš (referee)
Currently, when there is a reduction of soil water due to drought, is appropriate measure to start systematic collection of data on soil moisture. In this work the soil moisture content was measured on the Litovicko-Šárecký brook basin near a small water reservoir Strand. The datat were collected by direct method, which mean direct soil sampling and subsequent analysis, and indirect methods concretely gathering data by TMS datalogger. Measured data from direct and indirect methods are essentially agree in this, that small water reservoir Strnad hasnt effect at soil moisture in a distance 200 m. The last part describes the analysis of grain soils using aerometrical methods. The resulting soil types are further used for calibrating the TMS datalogger.

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