• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 535
  • 37
  • 5
  • Tagged with
  • 577
  • 391
  • 83
  • 80
  • 76
  • 72
  • 71
  • 67
  • 66
  • 65
  • 64
  • 61
  • 53
  • 53
  • 48
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Management vodních zdrojů: Případová studie nedostatku vody v Mexico City / Water Resources Management: A Case Study of Water Shortage in Mexico City

Krpatová, Kateřina January 2010 (has links)
In the two past decades, the topic of water resources has occurred more abundantly, the water has become the object of many research institutions. While in the 19th and 20th centuries of human progress took place under the sign of coal and oil, today is coming to the forefront the issue of availability of water resources and the related need for effective management which would assure an even distribution. This diploma thesis aims to highlight the problems of water resource management, offers options which would be theoretical focused and an example case study to show what the consequences may have a system which is implemented in isolation without consideration for other inter-sector policy. The context which involves on the current situation of water shortage in Mexico City is identified and analyzed.
82

Využití vodních bezobratlých pro studium environmentálních změn vodních toků / Freshwater macroinvertebrates and their use for assessment of environmental changes in running waters

Kolaříková, Kateřina January 2013 (has links)
The dissertation thesis consists of five articles, bringing together results from investigations of macroinvertebrates in running waters. The use of freshwater macroinvertebrate organisms to assess environmental changes was based on the following facts: a) the presence/absence of taxa provide information about abiotic factors and/or about the pollution status of the site, b) they are indigenous and sedentary species, so that the environmental implications can be related to the site they live on, c) the organisms accumulate xenobiotic elements or compounds, thus reflecting the contaminant level in the environment. Localization of the sampling sites was related to the "hot-spots" of environmental problems. The particular investigations were carried out in the Elbe River catchment and in the Czech mountains on the selected headwater streams of the GEOMON network of the Czech Geological Survey. The Elbe was considered one of the most polluted rivers across Europe in the second half of the past century until the socio-economic transformation after 1989. The headwater streams in the Czech Republic were chosen with respect to the problem of acidification. The ability of bioaccumulation of xenobiotics in macroinvertebrate organisms was used to assess the long-term load of the Elbe ecosystem with trace...
83

Kvalita vody a složení planktonních společenstev vodní nádrže Opatovice

Hylák, Tomáš January 2014 (has links)
The aim of the diploma thesis was a seven month research at the valley waterworks reservoir called Opatovice by Vyškov na Moravě. Taking of the water samples was carried out once a month from two sampling places, which were located on the leeward and windward sides. On the same day these water samples were analyzed at the Fishery and Hydrobiology Department of the Mendel Univerzity in Brno, where there were determined physical and chemical parameters of water, quantitative and qualitative content of the plankton associations. The results were compared with my bachelor thesis: The Development of the Quality of Water in the waterworks reservoir Opatovice, with the results from the previous years, which were provided by the Water Supply and Sewerage company, plc in Vyškov, with the valid legislation of the Czech Republic and with selected waterworks reservoirs situated in the south Moravian region.
84

Rychlost kolonizace nově vybudovaných rybníků makrozoobentosem

Petrovajová, Veronika January 2014 (has links)
Presented diploma thesis deals with the topic of colonisation of newly build fishponds by macrozoobenthos organisms. Most of the authors devote to colonisation of running or periodic waters but colonisation of standing waters is more likely neglected topic. Observed locality is placed in the Northern Moravia. Three fishponds in the newly created pond system were sampled from spring till autumn during the first year after building. Qualitative samples of aquatic biota were taken by hand-net. Macrozoobenthos of fishponds was evaluated from the taxonomic structure and abundance point of view. Due to the high proportional representation of Chironomids and a lack of autecological demands of particular taxa, distribution of organism into particular functional groups was not realized. The influence of fish stock as well as short time period from the pond creation were assessed as the main factors of low taxonomic composition and low abundance of macrozoobenthos. Simultaneously, the physicochemical parameters (temperature, dissolved oxygen, pH and conductivity) of water of fish ponds were monitored. Those were assessed as suitable for stated fishponds types and should not eliminate neither the rearing of fish nor the presence of aquatic invertebrates.
85

Strukturní a hydrologické poměry skalních mís České Kanady / Structural and hydrological characteristics of weathering pits in Česká Kanada

NOVÁKOVÁ, Alena January 2015 (has links)
This Masetr thesis looks into weathering pits of nature park Česká Kanada. The theoretical part of the thesis investigates research of weathering pits done in the Czech Republic as well as abroad. The practical part deals with weathering pit-bearing as well as weathering pitabsent blocks of rock within the study area. It describes their geological-geomorphological environment and attempts to find differences between the weathering pit-bearing and absent blocks (the presence of cracks, altitude, landforms, shape of the rock block and more). Furthermore it was established that a suitable rock block morphology (respectively the existence of horizontal plane) is important for formation of weathering pits. It also studies water properties in selected weathering pits, relationship of overhangs to prevailing wind directions. A correlation between overhang and wind direction was found in sense that NW to W winds correspond with overhang formation on eastern sides of weathering pits. Water in weathering pit of Čertův kámen located in sunny bare landscape shows significantly different properties in comparison with water properties of remaining weathering pits located in forrested areas.
86

Složení planktonních společenstev a kvalita vody Pístovického rybníka

Plišťáková, Lucie January 2015 (has links)
This work focuses on changes in the composition of planktonic communities and water quality in the Pístovice pond. Samples were collected and monitored throughout the year. They were collected at the same locations everytime, mostly at the same time, one month apart. Then Theky were processed subsequently in a chemical laboratory at the Faculty of Agronomy, Institute of Zoology, Fisheries, Hydrobiology and beekeeping. The results show us the composition of planktonic communities (phytoplankton and zooplankton) and their representation and changes during the year. At the same time we can find out the chemical composition of the monitored parameters and their progress and final water quality. These changes are closely related to the change of temperature in the area and subsequently changed one parameter affects the second and the closely related and the composition and representation of individual planktonic communities. The works conclusion is that the chemical parameter values of Pístovice pond water including the composition and representation of planktonic communities fall within the typical values of the chemistry of our stagnant water and ponds.
87

Vliv zvolené strategie na efekt počátečního odchovu jesetera malého (Acipenser ruthenus) v kontrolovaných podmínkách

Dostál, Jan January 2015 (has links)
The thesis summarizes findings from the field of initial rearing of sterlet (Acipenser ruthenus) that are currently available. The results of experimental rearing, which took place in 2014 and consisted of two parts, are included. In the first part, the impact of the exchange rate of the water in the tanks on change of hydrochemical parameters. For the experiment three variants in duplicate were prepared, with different flow rate for each one. The volume of water in the tanks was set to 100 liters and the number of fish was 150 fish/tank. Water change rate within the first variant was set for 1/3 of volume per hour, within the second variant for 1/3 of volume per hour and within the third variant for 3/3 of volume per hour. Each day was measured oxygen content, water temperature and pH, and samples for laboratory analysis were being taken. The results were analyzed by analysis of variance. No statistically significant difference has been found between monitored parameters, therefore these flow rates had no impact on the change of hydrochemical parameters for each variant. In the second part of the experiment was compared the effect of three different feed mixtures on growth parameters and development of fish. The same conditions of the rearing environment were maintained, but stocking density was reduced to 50 fish/gutter and a uniform water change rate of 3/3 volume per hour was set. The first variant was presented feed Aller Bronze 2 mm, the second variant Aller Silver 2 mm and the third variant Biomar Inicio 918 2 mm. At the beginning of the experiment, the fish reached an average piece weight of 29.00 g and FWC 0.44 within the first variant, 29.70 g and FWC 0.43 within the second variant and 29.31 g and FWC 0.41 within the third variant. At the end of the experiment the fish reached monitored parameters with following values: the first variant had the average piece weight of 37.99 g, FWC 0.41, SWGR 0.90 %.d-1, FCR 2.12 kg.kg-1 and PER 1,01; within the second variant, the average piece weight was 40.38 g, FWC 0.41, SWGR 1.02 %.d-1, FCR 1.82 kg.kg-1 and PER 1.18; within the third variant, the average piece weight was 43.51 g, FWC 0.40, SWGR 1.44 %.d-1, FCR 1.44 kg.kg-1 and PER 1.46.
88

Vyhodnocení účinnosti čistírny odpadních vod v Náměšti nad Oslavou

Pivoňková, Helena January 2015 (has links)
The thesis "The Evaluation of the Effectiveness of the Sewage Disposal Plant in Náměšt nad Oslavou" compares the effectiveness of two wastewater treatment technologies, the first and the current one. The practical part deals with the importance of treatment of sewage and the overview of the legislation dealing with water. It also describes the types of wastewater, some indicators of pollution of water from sewage and particular possibilities for wastewater treatment. The practical part contains a description of wastewater management in the town. It also describes of the historically first and the current wastewater treatment technologies and contains the survey of the water permits intended for water management. The chapters "Evaluation of Results" include graphs of the results of the analytical control of wastewater and the defined flow rates. The results show that the first-ever sewage disposal plant was insufficient for the needs of the city, which led to the construction of a new wastewater treatment plant. The existing wastewater treatment technology is adapted to the current needs of the city and is also taking into account its future development. The existing wastewater treatment plant fulfills the minimum requirement values of the wastewater treatment efficiency. The concentration of the pollution of wastewater at the wastewater treatment plant does not exceed the prescribed emission standards. The hydraulic and substance demand on the technology achieves the mean value.
89

Využití solárních kolektorů v České republice / The use of solar collectors in the Czech Republic

Kočka, Jan January 2016 (has links)
The aim of this thesis was to approach the market of solar systems in the Czech Republic and the subsequent design of the solar system in the selected object, in this case RD Divišov. In the chapter Overview of the findings from the literature there are outlined the general knowledge about the Sun and the use of solar radiation. In addition, this chapter provides a general overview of solar collectors followed by the approach of the necessary elements for the functioning of the solar systems. In the chapter Default conditions of the solved object there is characterized the selected one, and there is described the current system in this object. Chapter The design of the solar system in a given object includes the proposal of individual elements of the solar set for water heating. There are compared variants with different demands, different input parameters on the basis of values and graphs chosen the most efficient option for this project. At the end, the economic evaluation of the proposed system with the subsequent comparison with the current system and possible return. The work is ended by summarizing of the whole issue.
90

Návrh kanalizace a čistírny odpadních vod v obci Maleč / Design sewerage system and WWTP in the village Maleč

Novotná, Barbora January 2016 (has links)
The thesis describes wastewater removal and subsequent handling. Also includes calculations and drawings of the proposed network and sewage treatment plant. Finally, work is designed sewerage system and wastewater treatment plant for the area. Area for which the sewerage system and wastewater treatment plant being proposed is Maleč village, which lies in Havlíčkův Brod district, north of Chotěboř. The benefit of this work is the comprehensive information on the issue of wastewater removal and subsequent purification plant. The information obtained will be used in the design of a new sewer system and wastewater treatment plant for the municipality Malec, which is currently built only rainwater drainage system and sewage is discharged into the pits and cesspools.

Page generated in 0.0363 seconds