National Repository of Grey Literature 76 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Numerical Model of Water Flow in the Upper Reservoir Nové Mlýny
Winkler, Stanislav ; Zachoval, Zbyněk (referee) ; Marton, Daniel (advisor)
Diploma thesis is focused on understanding problematic of sedimentation in reservoirs with relation on flood episodes. For creating numerical model was necessary to ensure data about morphology of the river, granular composition of the riverbed and hydrology data. In thesis is written how were obtained these documentations, description of creating numerical model in program HEC – RAS 5.0.7. and results of done simulations of real flood episodes, which took place in years 2004, 2005, 2006, 2009, 2013. Output is evaluation each flood episode, description of grain class curves and evaluation of yearly flow before change of riverbed due to transport of sediments and after change of morphology of riverbed.
Study of sediment transport Moravanský potok flow in relation to extreme flows and drought
Pojsl, Václav ; Půža, Pavel (referee) ; Veselý, Jaroslav (advisor)
This bachelor thesis will concentrate on sediments study of Moravanský potok. In the introduction the study focuses on the description and photographic documentation of the situation of Moravanský potok before and after treatment flow. In following chapters it deals with granulometric analysis of Moravanský potok including the calculation of sediments. The study also describes the morphology of the area and influence by water management ratios. In the final part of the thesis are assessed the survey data of the situation of Moravanský potok and the recommendations how to reduce sedimentation.
Geochemical Study: Sediments as a Source and/or Trap of Mercury Contaminatin.
Májska, Milada ; Amouroux, David (referee) ; Zdeňka, Svobodová (referee) ; Dočekalová, Hana (advisor)
Rtuť je v přírodě přirozeně se vyskytujícím toxickým prvkem, jehož globální emise jsou ovlivňovány zejména antropogenními zdroji znečištění. Obrovský globální nárůst v usazování rtuti, zejména ve vodných ekosystémech, byl zaznamenán současně s počátkem průmyslové revoluce. Sedimenty jsou posledním místem úložiště nejrůznějších komplexů rtuti. Rtuť však zde může být přeměněna na toxičtější organickou formu, methylrtuť, pomocí transformačních procesů kontrolovaných různými fyzikálními, chemickými, ale i biologickými faktory. Navíc mohou být specie rtuti remobilizovány ze sedimentů pomocí difuze a resuspenzace a tak se sedimenty mohou stát i potenciálním zdrojem rtuti. Proces bioakumulace a bioobohacování tak pokračuje v potravním řetězci, ve kterém se člověk, i další zvířata, stává konzumentem methylrtuti. Stanovení celkové koncentrace rtuti není dostačující k porozumění osudu rtuti v přírodním prostředí a tak stanovení MeHg poskytuje nezbytnou doplňující informaci. Dostatečně citlivá a přesná analytická metoda pro stanovení specií rtuti je nezbytným nástrojem environmentální chemie. Metody vhodné pro stanovení specií rtuti v sedimentech jsou popsány v části metodologie disertační práce. Metoda stanovení methylrtuti v sedimentech pomocí automatické Headspace vybavené pastí („trap“) a spojené s plynovou chromatografií a fluorescenční detekcí je zde také popsána. Zvláštní pozornost je také věnována potřebám zásad čistého vzorkování, skladování vzorků a přípravě vzorků před samotou analýzou, jakož i samostatné části věnující se terénní studii rtuti a methylrtuti v sedimentech vytipovaných lokalit. Sedimenty jižní Moravy a severní Francie jsou srovnány z hlediska znečištění rtutí. Specie rtuti a další ukazatele (Fe, Mn, S) byly analyzovány v sedimentech, pórové vodě a povrchové vodě řek Dele a Lys (Francie) a Jihlava a Morava (Česká republika). Z hlediska posouzení vodních ekosystémů a jejich znečištění rtutí, je vhodné znát koncentraci rtuti v pórové vodě a posoudit dostupnost rtuti ze sedimentů. Technika difuzního gradientu v tenkém filmu je vhodným způsobem jak stanovit koncentraci rtuti v pórové vodě sedimentů. Do roku 2005 bylo použití této techniky pro měření rtuti značně limitováno. Ale nedávný pokrok především v dostupnosti možných sorpčních gelů vhodných pro stanovení rtuti umožnilo využití této techniky i pro stanovení rtuti. Byly použity různé sorpční gely: Spheron.Thiol, Duolite GT-73 a TiO2. Řeka Dele představuje past enormního množství antropogenní rtuti pocházející z průmyslových zdrojů a je považována za potenciální významný zdroj methylrtuti pro okolní prostředí a živé organismy především. Poslední část dizertační práce se zabývá aplikací dobře zavedeného experimentu využívajícím stabilní isotopy ke studiu metylačních a demethylačních procesů v sedimentech řeky Dele. Obohacené stabilní značkovače rtuti v anorganické formě (199Hg) and methylované formě (201MeHg) byly přidány do sedimentů. Tyto označené specie rtuti tak pomohly sledovat osud specií rtuti a vypočítat rozsah jejich přeměny v průběhu experimentu.
Determination of active zone of bed load sediment trap
Sodomka, Václav ; Pařílková, Jana (referee) ; Zachoval, Zbyněk (advisor)
The bachelor thesis deals with determination of the active zone of bed load sediment trap in the water reservoir of Nové Heřminovy. A ready-made physical model of the sediment space was used and more accurate measurements of behaviour of the proposed object were performed. Ultrasonic speed field measurement was used for determination of the active zone of the sediment space. The Surface-water Modeling System programme was applied for evaluation. This information can be used for further assessment of bed load sediment trap. The results show that transported bottom sediment is trapped in the space determined for this purpose and there are no unforeseen phenomena. The model behaves within the limits of the initial assumptions. That means it is correctly designed and it will be more likely to serve its purpose.
Specification of the movement of sediments in the selected section of the flow in the vicinity of the polder Žichlínek
Kaizar, Jan ; Půža, Pavel (referee) ; Veselý, Jaroslav (advisor)
The bachelor thesis defines sediment transport in selected section of Moravská Sázava river, and Ostrovský potok stream in the area of Žichlínek detention basin. The first part of the thesis focuses on documentation of the current situation of the selected area. Following part deals with granulometric analysis of taken samples and their assessment. Next part is dedicated to calculation of the amount of the sediment, and suspended solids in the studied watercourses. The final part of the thesis describes as the sediment transport impacts on both the stream bed clogging, and the passage of a flood wave through the area.
Monitoring of water and sediment contamination
Grajciariková, Eva ; Mravcová, Ludmila (referee) ; Vávrová, Milada (advisor)
The diploma thesis is focused on the issue of the presence of POPs in the surface water and sediments. Monitored compounds were chosen from the group of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDE). Samples were collected in selected localities in the Slovak and the Czech Republic. Selected analytes were extracted with hexane from the aqueous matrix. Analytes were isolated by the ultrasonic extraction using a solvent mixture of hexane-dichlormethane from the solid matrix and the resulting extract was cleaned up by the column chromatography filled with the florisil and the silica gel. Target compounds were analysed by GC/ECD finally. Obtained results show the level of contamination in selected localities in the Slovak and the Czech Republic.
Sewage sludge and sediments evaluation via ecotoxicity tests
Ondrová, Jana ; Vávrová, Milada (referee) ; Zlámalová Gargošová, Helena (advisor)
Sediments and sewage sludges are part of the environment. Sewage sludges are formed in wastewater treatment plants as solid residues after water purification, therefore they have antropogenic origine. Although the sediment are formed by natural processes, humans also contribute to their formation. Sediments and sewage sludges can be a reservoir of a number of contaminants, due to their properties. Utilisation of sediments and sewage sludges as material for recultivation or a natural fertilizer is currently supported. But after application to the land, contaminants can be released to the environment. The consideration of ecotoxicological effects of sediments and sewage sludges is very important. Sediments and sewage sludges were ecotoxicologicaly evaluated by bioassays with water leacheate and by whole sediment bioassays. Daphnia magna, Thamnocephalus platyurus, Sinapis alba and Lemna minor were used to perform tests with water leacheate. Heterocypris incongruens, Lactuca sativa and Eisenia fetida were used to perform whole sediment tests.
Tin and his species in the environment
Bušinová, Markéta ; Moos, Martin (referee) ; Doležalová Weissmannová, Helena (advisor)
Presented bachelor thesis is background research on tin and his species in the environment. Mainly deals with the effects of inorganic and organic compounds of tin on elements of environment. The work resumes accessible information about properties of tin and his compounds, entry of tin and his compounds into the elements of environment, cycle and occurrence of tin speciation in water, soils, sediments and biological materials.
Sediment deposition in reservoir of Nové Heřminovy dam
Kammermayer, Jan ; Šedivý, Jiří (referee) ; Zachoval, Zbyněk (advisor)
The thesis deals with silting of water reservoir Nové Heřminovy. There's describe design of artificial traffic and evaluate its effectiveness. To determine the flow of sediment into the reservoir with use a partially calibrated one-dimensional numerical model of sediment transport with deformation of bed is made in software HEC-RAS. Silting reservoirs is assessment with two methods, the results are compared and describes their limitations. Reservoirs silting evaluates through volume changes in reservoir storage in time.
Ecotoxicological evaluation of sediments
Dobešová, Zuzana ; Doležalová Weissmannová, Helena (referee) ; Zlámalová Gargošová, Helena (advisor)
Sediments of lotic and lentic water can be a reservoir of a number of contaminants, which can enter the aquatic ecosystem either due to the controlled discharge of waste water or leakage of various accidents or technological devices. Sediments can hereby affect not only the aquatic ecosystem, but also the terrestrial system in the case that they will be used as fertilizer or as a material for the recultivation. For this reason it is important to consider their potential ecotoxicity. Sediments were subjected to ecotoxicological bioassays and their potential ecotoxicity was assessed. The phytotoxicity assays on terrestrial plants Sinapis alba, Lactuca sativa and Allium cepa were used and the effects of aqueous extracts of sediments on the inhibition of growth their root were evaluated and the value of IC50 was determined. For the ecotoxicological assessment of sediments and determination of IC50 value also Lemna minor as a representative of aquatic plants was selected. For more objective assessment of the sediment ecotoxicity aquatic invertebrates as Artemia salina and Daphnia magna were selected and the value of LC50 or EC50 was determined.

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