National Repository of Grey Literature 3,333 records found  1 - 10nextend  jump to record: Search took 0.08 seconds. 


Role of wetlands in water budget of landscape
Pokorný, J. ; Lhotský, R.
Wetlands are unterstood as shallow, seasonally or permanently waterlogger or flooded areas which normaly suppostr hydrophytic vegetation. Various definitions of wetlands are given. Water retention above soil surface, in wetland soil and role of wetland plants in water cycle and solar energy dissipation are briefly explained. Examples of long term monitoring water retention in a peat bog and functioning of a wetland landscape during flood are given. Role of watelands in landscape restoration is mentioned.

The Controlling Study
Herda, Tomáš ; Mikovcová, Hana (advisor) ; Herda, Zdeněk (referee)
The main goal of this Diploma´s Thesis is to make a model for calculation of water and sewer rates for the company Vodovody a kanalizace Náchod, a.s. when sticking to the set criteria both from the side of VaK Náchod, a.s. and law regulations. Based on the theoretical part an analysis of customer sensitivity to the price changes using the data for last 20 years follows. Findings from the first two parts are used in risk analysis in next part. The created model calculates the water and sewer rates based on the information from the company accounting system in the way to generate sufficient financial resources to fulfill the renovation plan of infrastructural property plant and equipment and to transfer given amount to the company funds. In addition, the model monitors whether the legal condition of maximal allowable increase of profit per m3 is met. In the customer sensitivity to the price changes part the price elasticity of demand for water and sewer rates is calculated based on the data from 1995 to 2015. The assumption of inelastic demand is confirmed. Risk analysis part is deals with potential risk regarding the demand and prices. Potential impacts for the most significant risk are quantified. The analysis uses knowledge gained in the first two parts. It was confirmed that potential risks are exiting but do not have any significant impact on the going concern of VaK Náchod, a.s. The created model has been already used for the calculation of prices for the year 2017. Customer sensitivity analysis to the price changes and link to the potential risks is an additional information for VaK Náchod, a.s. which validates that nowadays, there are no significant threats which could affect the demand and water and sewer rates significantly.

Tube heat exchanger for heating water.
Novotný, Roman ; Rostislav, Ratkovský (referee) ; Skála, Zdeněk (advisor)
Target of the master´ thesis is a design of heat exchanger air-water with the air flowing inside the pipes and with staggered pipe configuration, based on the engaged and chosen values. Next target is to determine heat exchanger with cross parallel flow and cross countercurrent flow of mediums, pressure drop on both sides air and water and dimensions of intake and outgoing gate on both sides air and water.

Pervaporation of Methanol Water Mixtures by PERVAPTM Asymmetric Membranes.
Izák, Pavel ; Kačírková, Marie
The report summarizes the results of experimental testing of pervaporative separation of methanol from methanol-water binary mixture at 35°C. For the separation were chosen the Sulzer´s PERVAPTM membranes. The concentration of methanol was 6.5 wt.% in water, and pervaporation was performed in vacuum mode. Membranes displayed separation properties suitable for industrial separation of methanol from water mixtures.

Energy balance of biomass heating plant
Žmolík, Václav ; Šen, Hugo (referee) ; Baláš, Marek (advisor)
This thesis deals with a design of a biomass heating plant combinating a Rankin-Clausius cyklus and a CHP unit. The CHP unit fuel is a biogas and the boiler fuel is a wooden chip. The adapted CHP unit regenerates feed-water of the R-C cycles. This design is technicaly and economicalty compared with the Rankin-Clausius cycle without feed-water regeneration by the CHP unit.

Arctic tundra dendrochronology
Lehejček, Jiří ; Svoboda, Miroslav (advisor) ; Monika, Monika (referee)
Historically unprecedented environmental change in the Arctic ecosystems is often given into the context of its past and possible future development. In the region where instrumental meteorological observations are scarce archives need to be investigated in order to address this issues. The comprehensive synthesis one of the archives: long-live circumpolar evergreen Juniperus communis L. shrub is presented here. 20 individuals from southwest Greenland were investigated at the cell anatomy level to understand the ecology of the species and unhide its potential for environmental and climate reconstructions. The findings are as follows: i) Stop of exponential cross-sectional conduit-lumen widening with increasing age is in contrast with conduit-lumen nature of trees. This indicates that shrubs do not need to saturate their water and nutrient demands via traits of classical hydraulic conductivity law but rather developed different mechanisms. Extreme weather conditions result in prostrate growth form. However, different weather factors probably influence shrub growth differently: While snow and wind act mechanically (a), temperature influences the form of growth physiologically (b). a) So long as the young shrub stem has high resilience to bend back to an upright position after snow melt and so long as it can withstand the wind during the vegetation season it most likely grows upright and the conduit-lumens widen. b) Temperature, resp. freeze-thaw events are responsible for the shrubs preference of safety (finite size of conduit-lumens) over hydraulic efficiency, thus not allowing for more primary growth. All of these (and other) factors are apparently working together and the transition of vertical to more horizontal growth is gradual. As a consequence, the conduit-lumen sizes may not have to be further increased (due to ecophysiological restrictions possibly also must not) because water is no longer transported against gravity. ii) Observed age/growth trend has to be taken into consideration for further employment of the wood anatomical parameter in paleoenvironmental studies. That is, shrub cell parameters can only be used for this purposes if correctly detrended. This allows for more accurate as well as longer reconstructions because youth trend was often neglected in reconstructions based on shrub annual-rings. iii) The south-western Greenland Ice-Sheet (GrIS) melt rates reconstruction is presented for the whole 20th century. This part of GrIS is considered as the most active. According to the presented reconstruction current GrIS melt rates are not uncommon for the last century being comparable to first decades of 20th century. This finding is particularly important contribution to the debate on Atlantic meridional overturning circulation (AMOC). Too high fresh water inputs into the Northern Atlantic from GrIS melting may slow down or even stop the AMOC which would result in more continental climate in Europe. Presented results indicate that this threshold lies higher than observed current melt rates of GrIS. Fascinating Juniperus comunnis species has shown to be able to address many ecological as well as environmental open questions and due to its longevity and abundant distribution has a great potential to become an important player in the Arctic research.

Steam generator for nuclear power plant with fast reactor
Karička, Radoslav ; Nesvadba, Lukáš (referee) ; Šen, Hugo (advisor)
The aim of the project is to design a steam generator in which the sodium flows pipeline hand, and on the other hand, water flow and water vapor (H2O). The main idea of this thesis is to propose such a steam generator, to avoid or eliminate the possibility of adverse reactions of sodium with water and, if this phenomenon occurs, thus minimizing the damage caused by this reaction. The work contains information on the implementation of steam, steam option, the necessary calculations for the design and construction and evaluation.

Design of horizontal combustion chamber
Nesiba, Petr ; Nekvasil, Richard (referee) ; Kermes, Vít (advisor)
This diploma thesis deals with a design of the water cooled horizontal combustion chamber for testing of burners with the maximum heat duty up to 2.5 MW. The design of horizontal combustion chamber is carried out with regard to the testing of different burner types. The proposal is elaborated up drawing documentation. The theoretical part of the diploma thesis describes briefly basic necessary theory about the classification of combustion chambers and burners. It was described advantages and disadvantages of basic group of burners. Last chapter of the theoretical part deals with a description of burner testing. The practical part of the diploma thesis consists of necessary calculations required for the determination of basic geometry of the combustion chamber and verification of the assumptions first of all the assumption of the bubbling evaporation of the water on the internal shell. It was carried out the strength calculation of the combustion chamber according to the standards and by means of Finite Element Method.

Evaluation of the Technical State of Water Treatment Plants
Přecechtěl, Karel ; Slavíčková,, Kateřina (referee) ; Kučera, Tomáš (advisor)
The subject of this thesis is to create evaluation criteria of technical condition of water treatment plants. The thesis is divided into four parts. In the first part of this thesis are presented evaluation systems by performance indicators drinking water treatment plants, which are then applied in real time. There are detailed descriptions of individual performance indicators. Each evaluation conducted certain period of time. After the expiry of the period under review was to evaluate and create charts to display results. In the next chapter the thesis focuses on the identification data. First, it was necessary to find out all necessary information about the water treatment plant. Necessary information means information relating to building construction, human resources, mechanical parts, technological equipment and other entities with links to the operation of the water treatment plant. All these data were sorted for better overview and facilitate setting evaluation indicators. The third part of this thesis is focused on the development of indicators that are used to determine the current status of the water treatment plant. As a first step was established 19 indicators used to evaluate the condition of the entire water treatment plant. Followed by a description of the individual indicators and then determine the individual evaluation criteria. In the last part of this thesis was carried out by the proposed criteria on selected water treatment plants. They were selected three water treatment plants located in the Czech Republic, which held a personal tour of each water treatment plant. This was followed by an overall assessment of the technical condition of water treatment plants.