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Dissolved and gaseous nitrogen losses in forests controlled by soil nutrient stoichiometry
Oulehle, Filip ; Chuman, T. ; Hruška, Jakub ; Krám, Pavel ; Navrátil, Tomáš ; Tesař, Miroslav ; Ač, Alexander ; Urban, Otmar
This study investigates the consequences of chronic nitrogen deposition in forests, including its effects on soil and surface water quality, and greenhouse gas emissions. To predict these effects, the authors explore the controls over dissolved and gaseous nitrogen fluxes in temperate forests. Their findings indicate that stream leaching losses of dissolved nitrogen correspond with the nutrient stoichiometry\nof the forest floor, with stream N losses increasing as ecosystems progress towards phosphorus limitation. Soil nitrogen storage increases with oxalate extractable iron and aluminium content. The authors estimate soil gaseous losses based on 15 N stocks, which averaged 2.5±2.2 kg N ha-1 year-1 , comprising 20±14% of total nitrogen deposition. They also extrapolate the current gaseous nitrogen loss flux from forests globally to be 8.9 Tg N year-1 , which represents 39% of current nitrogen deposition to forests worldwide.
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Process computer simulation
Čech, Michal ; Pavlas, Martin (referee) ; Touš, Michal (advisor)
The thesis deals with computer simulation of processes, which is crucial in the field of process engineering. In the first part, the methodology of modeling and simulation techniques is described as well as mass and energy balances. Specific approaches to process simulation are included. The thesis offers a list of the most often used simulation programs and their typical structure. Sequential modular and equation-based simulation is demonstrated on an example. The results are then verified by simulation software W2E.
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Treatment of Waste Water Treatment Sludge Prior of its Following Utilization
Pěček, Jan ; Klemeš,, Jiří (referee) ; Žaloudík, Petr (referee) ; Jícha, Jaroslav (advisor)
Industrial production of cellulose is an energy intensive process. Businesses aim to utilized as much input energy, materials as possible while minimizing the waste as well. In addition to the main product – cellulose and large amounts of organically polluted water which is subsequently treated in waste water treatment plants. This PhD thesis deals with formation of suitable mixing formula for sludge from cellulose production and available materials (waste) from close neighborhood of Biocel Paskov a.s. so that well balanced cofermentation products are achieved. This mainly involves grass from lawn maintenance, grass ensilage, potato peels, and leftovers from vegetable processing. Fermentation processes (both mesophilic and thermophilic) of prepared fermentation products were conducted in semi-continuous and continuous laboratory fermentation units. Reduction of organic mass depending on residence time was closely observed as well as production and quality of biogas along with quality of output digestate. Course of process behaviour under controlled pH was tested. Results of particular tests were integrated into graphs. Conclusion of the thesis presents balance scheme drawn for selected variants, and design of real fermentation station with individual buildings, operations, basic machinery and equipment description including investment costs. Financial calculation and expected investment return was conducted in two variants – without subsidies and including subsidies from Operational Programme Renewable Sources of Energy.
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Microtextures and compositional relations in multiple grown garnet formed during subduction of crustal and mantle rocks
Kulhánek, Jan ; Faryad, Shah Wali (advisor) ; Collett, Stephen (referee) ; Konrad-Schmolke, Matthias (referee)
English abstract Studies of rocks from high- to ultrahigh-pressure metamorphic environments in subduction zones play a crucial role in advancing our understanding of Earth's dynamic processes and geodynamic evolution. Such samples, which have experienced Earth's mantle conditions, provide valuable insights into the subduction and exhumation processes associated with the tectonic collision of lithospheric plates. By analysing the mineral assemblages, textures, and chemical compositions of these rocks, we can unravel the complex history of the subducted rocks and determine the pressure-temperature paths experienced during their formation. Additionally, the investigation of high- to ultrahigh-pressure metamorphic rocks aids in constraining the mechanical behaviour of subduction zones, deciphering the fluid-rock interactions and element cycling processes. Such studies contribute to our broader understanding of plate tectonics, the formation of mountain ranges, and the geodynamic processes that shape our planet. This research focuses on the investigation of metapelitic and metabasic rocks from the Saxothuringian zone of the Bohemian Massif and the Western Gneiss Region of the Norwegian Caledonides. The studied rocks have a shared history of being part of subducted material that experienced high- to...
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The processing of stabilized sewage sludge by high-temperature slow pyrolysis and gasification
Bičáková, Olga ; Čimová, Nikoleta ; Vöröš, Dominik ; Náhunková, Jana ; Řimnáčová, Daniela
One of the most challenging type of waste is sewage sludge, which is a heterogeneous suspension containing organic and inorganic substances and pathogenic organisms. This work focuses on an effective application method for the sewage sludge, which is usually deposited in landfills or co-incinerated in power plants. High temperature pyrolysis and gasification at 700–900 °C were applied to the samples of stabilized sewage sludge. The samples with a constant weight of 100 g were heated in a stationary bed, with the rate of batch heating being monitored. During the heating process, volatile products were released and the composition of the gaseous products developed during the heating was analyzed. Afterwards, the mass balance of the resulting products was evaluated. The elemental and textural analyses of the products were performed. Furthermore, it has been found that the solid residue has a porous texture and properties suitable for the removal and capture of pollutants. \n
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Long-term trends in water quality of pond Světin relation to fish management
Altmann, Martin ; Duras, Jindřich (advisor) ; Vrba, Jaroslav (referee)
Fishpond ecosystems provide many other services besides fish production. One of them is the retention of nutrients and thus ability to change the quality of the through flowing water, thereby ability to influence the overall quality of surface waters. In the case of the fishpond Svět in Třeboň it is also recreation, as the pond is an integral part of the tourism of the town. Water quality in the fishpond and its retention capacity of phosphorus is connected with the fish management and the inflow of nutrients from the catchment basis, especially within a cascade of ponds and densely populated or agricultural regions. This thesis evaluates seasonal (2013, 2015) and long term (2007-2015) trend of water quality of pond Svět in Třeboň in relation to fish management. Furthermore, mass balance was calculated for 2015 and estimated for 2013. The years 2015 and 2013 (the first years of production cycle) varied considerably in amount of annual rainfall. The year 2015 was extremely dry and 2013 very aqueous. Different hydrological conditions caused different seasonal courses in hydrochemistry parameters and its concentrations. The water quality of fishpond Svět is in the most of parameters better in comparison with other production fishponds in the Třeboň region and also the intensity of fish management is...
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Hydrology of mountain seepage lakes
Kohn, Tomáš ; Stuchlík, Evžen (advisor) ; Šobr, Miroslav (referee)
The aim of this thesis is a review of the hydrological balance of mountain lakes, focusing on lakes without ground outflow, or with a huge share of seepage upon the outflow. This thesis deals, step by step, with the methods of collecting data for each input and output to the hydrological system. It is also concerned with the possibilities of monitoring ground water movement and rainfall-runoff models.
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