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New generations of PVD coatings
Kantar, Filip ; Kolář, Ladislav (referee) ; Jaroš, Aleš (advisor)
Bachelor thesis deals with methods of coating, cutting tools and a new generation of coatings. In the first part are listed and described basic coating methods. The next part is aimed on coating of PVD methods. In the third part are listed basic tool materials and their characteristics. The last part is focused on new generation of coatings, their application, properties and structures.
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Coated cemented carbides
Foltýn, Michal ; Sedlák, Josef (referee) ; Humár, Anton (advisor)
This bachelor’s thesis is focused on coated cemented carbides, methods for coatings and properties of coatings. In the first part of this thesis there is mentioned basic subdivision of tool’s materials, including description of properties and possibilities of their use. Another part of this thesis is focused on the coating deposition methods. As each method there is noticed the description, advantages and disadvantages. In next part there are described processes which precede own deposition process and their influence on properties of coatings. In this thesis are also described properties of coatings and methods for their testing. The last part of thesis is focused on the offer of certain producers of coated cemented carbides. Several materials are chosen from each producer and there are mentioned descriptions of their properties, structure of coatings and possibilities of using.
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Assessment of Efficiency of waterborne penetrations for cement substrates
Hlawiczka, Jakub ; Tupý, Michael (referee) ; Petránek, Vít (advisor)
The bachelor's thesis is addressing the issue of using primer coatings for cementitious surfaces. It analyzes reasons of using primer coatings and specific features of application. There are mentioned different species of surface treatment for cementitious surfaces which is followed by methods of surface treatment by variety cementitious screeds, and self-leveling flooring systems. Then it is looked into general characterization of polymer dispersions (especially water-based dispersions) which have typical attribute for primers. In experimental part of thesis are compared ten different waterborne primers. Testing is briefly described and evaluated.
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The effect of periphyton on the development of macrozoobenthos in ponds
URBÁNEK, Marek
The aim of this study was to evaluate the effect of two types of artificial substrate enhancing periphyton development on macrozoobenthos community in ponds in which larvae of pikeperch (Sander lucioperca) were cultured to advanced fry. The experiment was divided into two time periods and was performed in twelve ponds in experimental facility of FFPW in Vodňany. In the first time period of the experiment (from the end of April to the beginning of June) there were three different treatments of the ponds established: a substrate from heather, a substrate from geotextiles and a control without any substrate. Each treatment had four repetitions. In the second time period of the experiment (from the middle of June to end of September) the substrate from geotextiles was removed and following options of the pond treatment such as the substrate from heather, releasing of prey fish into the four ponds and no support of periphyton (a control) were applied. In the course of both experimental time periods samples of substrate and bottom macrozoobenthos were taken in ponds each 3 weeks. According to statistical analysis, significantly higher abundance of macrozoobenthos was found on the substrate from heather in comparison to substrate from geotextiles (F (1, 6) = 12.897, p = 0.011). Mean values of the species abundance and the species biomass were always higher in the bottom macrozoobenthos than in the substrate macrozoobenthos. Mean values of diversity index were always higher in the substrate macrozoobenthos than in the bottom macrozoobenthos. The effect of the pond treatment on development of the bottom macrozoobenthos was not confirmed. The influence of the geotextiles on enhancement of fish production was rather negative. The substrate from heather increased the production of advanced pikeperch fry at 7 - 21 %, in the first time period of the experiment. Thus, next further research in this field can be beneficial regarding effective culture of some important fish species.
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The application of different types of substrate in the biogas plant
SIKYTOVÁ, Pavlína
Support and investment´s subsidies of production of electricity from renewable sources after 2009 made a phenomenon from a biogas plants. This thesis specifies the most used feedstock for biogas production in the Czech Republic. Each substrate used in biogas plants, have different chemical composition, dry matter content, thus providing another volume of biogas. Specifications of elections of substrate, was made on the based on consultations with the operators of agricultural biogas plants. Stabilized anaerobic process increases the production of biogas and supports economic situation of farms.
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Effect of ponds and pond systems on the composition of the benthos in horní Lužnice
SVAČINA, Petr
The work is focused on monitoring changes in benthic communities in the longitudinal gradient of the river Lužnice. The river flows through to the pond area Třeboňsko and the largest pond of the Czech Republic - Rožmberk. It is examine affect of pond on benthic communities. The work involves collecting benthos according to the PERLA method on four profile in four seasons, the analysis of chemical parameters and data processing. The values of SI (saprobiological index) in the longitudinal gradient were from SI 1.8 to SI 2.6. SI values were at the outflow of Rožmberk higher than at inflow. The lowest values were in the first profile Suchdol (SI 1,8 ? SI 2,1) and higher values were in the last profile Vlkov (SI 2,4 ? 2,6). The chemical parameters at outflow were observed increased values of BOD5, TOC, NL105, NL505, chlorophyll and total P but lower values of nitrogen forms (Ntotal,NH4, N-NO3-). On the each profile was the significant change in the incidence or absence of certain groups. Profiles Suchdol and Hlína were diferent than Lužnice and Vlkov especially in the presence of stoneflies, dragonflies, beetles, and individuals generally indicates good water quality. Profiles at outflows from Rožmberk (Lužnice and Vlkov) showed a continued presence of bloodsuckers and more species indicating high organic pollution. NMDS method confirmed impact of sites in communities rather than period (R2 = 0.6 at significance level of p = 0.001).
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The influence of substrate on performance of biogas palnt
RATAJ, David
In the master thesis the focus is laid on assessment of data and values from particular biogas generation units. For this topic I introduced in particular chapters of the thesis own opinions and experience of various experts. Expert data have been compared with own results gained by testing and evaluation of such received data. In this master thesis further technical parameters for the technology of anaerobic fermentation have been put together as well as information and data about other new technologies for biogas treatment and cleaning. Attention has been paid also to the outlook for using this environmentally friendly and green way of energy harvesting in the future.
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An experimental study of initial succession on different substrata: analysis of changes in plant species cover and some soil biological parameters and their relationships
KRESÁČ, Martin
A four year experimental study of initial stages of succession on different substrata (sand, peat and gray clay overburden from brown coal mining) was carried out. The substrata were transplanted into two different landscape types in the Czech Republic. Control plots were filled with autochthonous topsoil treated with high temperature vapor. Plots with un-treated autochthonous topsoil were also established. Plant species cover and several soil-biological parameters (soil microbial biomass, basal soil respiration, exchangeable pH(KCl), organic-C extractable by potassium sulfate solution, and nitrate-N content) were measured once a year. Obtained data were mainly processed by unimodal (plant cover data) and liner (soil-biological data) ordination methods. Biological species traits (life span, seed dispersal vector, seed bank type, ecological strategy type following Grime, life form following Raunkiaer) were used to characterize early stages of plant succession. Vegetation and measured soil-biological parameters, except pH(KCl), were significantly changing during four growing seasons. Variance partitioning analysis based on plant species cover data indicated the landscape type to be the main governing factor and physico-chemical characteristics of substrate to be less important during the studied initial stages of succession. The same analysis based on soil-biological parameters showed the reverse result. Great variability of plant species ecological traits was noticed during four growing seasons. The earliest plant colonizers were mainly ruderal, anemochorous terophytes with persistent seed bank. The number of species with C-strategy type increased during the study. The relationship between the average plant species cover and measured soil-biological parameters was also examined during the experimental study of early succession. Direct and indirect ordination revealed the average sum of plant species cover to be weakly positively correlated with soil microbial biomass, basal soil respiration, nitrate-N, potassium sulfate extractable organic-C, metabolic quocient (qCO2) and negatively correlated to exchangeable pH(KCl). The relationship was significant only in the case of microbial biomass and potassium sulfate extractable organic-C. More detailed studies of the relationship between aboveground plant species biomass and soil microbial communities in initial stages of succession are required. Comparability of presented study is limited because not many experimental investigations of similar kind have been presented until now.
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Comparison choice cultural and weed kinds form stock Amaranthus
VÁLEK, Jan
Amaranthus (L.) belongs to among old cultural crops. Cultural forms of some species were already grown by Aztecs and Incs in ancient times. High nutritive value of seeds redounded to rediscovery of the crops. Tested varieties of cultural amaranth get to the interaction whit wild species of amaranth. This work would had contribute to better knowledge of ecology in the hybrid of cultural variety and weed (A. x turicensis = A. cruentus x A. retroflexus) The aim of this work was to describe production and morphometric characteristics of selected relative cultural and weed species of amaranth (Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus retroflexus), the hybrid A. x turicensis and to determinate occurrence and survival of weed species A. retroflexus onplaces, where cultural amarant was grown. A. retroflexus shows as a very resistant to damage. Cultural species responded on damage by reduction of majority observed parameters. Cultural species of amaranth responded more on different conditions substrate than the weed species. Response of hybrid on different substratum conditions was in the middle of spectrum of the response in cultural parents and the weed species. Indiference of the hybrid to substrate should be better clear up in the next studies. Weed species is little sensitive to competicion and his characteristics (total biomass, legth inflorescence, height of plants, number of leaves) are different not much. Effect of competition on hybrid shows his non - uniform response probably caused by his considerable variability Absence of cultural amarant and interspecific hybrids shows on relation of these plants to warmer weather that is probably the main factor for their occurrence.
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