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Sources of nitrate in lower reach of Jizera alluvium: unsaturated zone and other sources
Hronec, Lukáš ; Bruthans, Jiří (advisor) ; Šanda, Martin (referee)
The water supply system Káraný (WSSK), which is using the water from Quaternary fluvial aquifer and induced recharge from Jizera River, is affected by increase of nitrate content in recent years. No tension lysimeters were emplaced into the soil at locality north of Sojovice and sampled roughly with monthly frequency. Samples were analyzed on isotopic content ( 2 H and 18 O of H2O) and chemistry. Volume of water collected in lysimeters was recalculated to mm/year. Infiltration tests demonstrated that infiltration rate at surface of agricultural land is low and therefore Horton surface flow is generated after heavy rains and during watering periods. Horton surface flow is disappearing into open desiccation cracks. This concentrated recharge may via preferential pathways transport nitrates via unsaturated zone. Using selected environmental tracers (Ca2+ a SO4 2- ) the portion of water from Jizera River in individual wells of WSSK was calculated. For Sojovice part of WSSK the water from Jizera River accounts for 71 - 80% of pumped groundwater and for Skorkov part of WSSK this is only 38 - 41%. The remaining part of water is either water from infiltration to Quaternary fluvial aquifer and/or water from Cretaceous Jizera Formation Aquifer. It is not possible to distinguish these two sources by means of...
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Design of boulder chute reconstruction in Lomná river at km 1,9
Hrabovský, Michal ; Golík,, Pavel (referee) ; Zachoval, Zbyněk (advisor)
The thesis deals the assessment of the resistance of the existing boulder chute in the river Lomná. At km 1,9 Boulder chute is located in the village Jablunkov. Surface resistance of boulder chute is assessed newly on the basis of non-dimensional shear stress for particle on arbitrarily sloped bed. The calculation of 2D flow was computed by HEC-RAS. On the assessment of resistance was proposed reconstruction of boulder chute.
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Impact of the troposphere on the inosphere
Koucká Knížová, Petra ; Mošna, Zbyšek ; Potužníková, Kateřina ; Boška, Josef ; Kouba, Daniel
Ionosphere represents weakly ionized plasma that reflects solar and geomagnetic activity and processes\nin the neutral atmosphere. Correlation of long time series of the ionospheric plasma critical frequencies,\nobtained by mean of vertical sounding from European stations, is analysed with respect to latitudinal and\nlongitudinal difference and surface distance of stations. Time series of critical frequencies are highly correlated\nreflecting the dominant solar influence. Correlation coefficients are high not only for raw data and subtracted\nmean courses but for fluctuations around mean as well. At the surface distance exceeding 1000 km and/ or about\n10 degrees of latitudinal difference between stations, the correlation coefficients of fluctuations decrease\nrapidly. Such effect is less visible on the latitudinal dependence, where the correlation coefficients decrease with\nincreasing distance with less pronounced threshold. We explain the existence of the ‘break point’ at 10 degrees\nin longitude and/or 1000 km by the ‘local’ influence of the neutral atmosphere and the wave activity. As a\npossible source of the common influence on scale 1000 km/10 degree we propose tropospheric systems that are\nknown to be an important source of atmospheric waves in a broad period range. Large tropospheric mesoscale\nsystems have typically up to 2000 km in size.
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Surface treatment of metals
Hamal, Jan ; Kubíček, Jaroslav (referee) ; Žák, Ladislav (advisor)
This master thesis describes design of suitable surface treatment technology to get component resistant to corrosion of conventional atmosphere. Given component has a shape of pin and is made of construction steel. At the beginning, there is a theoretical study of galvanic zinc coating and galvanic surface treatment in general. Then there is analysis of damaged galvanic zinc surface and its impact of corrosive resistance of that layer with collaboration with company KOZÁK SVITAVY. Corrosive resistance of damaged zinc layer is then compared with corrosive resistance of quality zinc layer. At the end of this thesis is technical and economic evaluation.
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Influence of thermal stress on volume and surface resistance of material
Rohel, Tomáš ; Rozsívalová, Zdenka (referee) ; Vaněk, Jiří (advisor)
This document describes the methods to test and measure the protective glasses used in solar panels. The next part of the dissertation covers the evolve summary for the norms of degradation tests. The purpose of this research is to scale the volume and surface electric resistivity of selected materials, as well as, specify the supposed durability of these materials. Evaluation of these features proceeds after enhanced aging by the use of dry heat. Samples of these materials were prepared with the cooperation of the company Solartec s.r.o
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Surface treatment of roll bearings
Kubelka, Milan ; Klakurková, Lenka (referee) ; Švejcar, Jiří (advisor)
The bearings are one of the most widely used construction components enabling mutual movement of parts and at the same time transmission of interacting load. The basic requirements placed on components of roll bearings are particulary increase of contact fatigue resistance, decrease of the friction coefficient between the rolling bodies and bearing rings, increase of hardness and abrasion resistance of functional surfaces, the wear resistance, corrosion protection and finally the electrical and optical properties too. As production of bearings from materials with these attributes would be quite expensive, surface modifications are used for improving the mechanical properties. The main task of this bachelor thesis is description and evaluation of technologies suitable for surface treatment of roll bearings with increased attention to those types of surface treatment which, in cooperation with SVÚM will be studied in more detail in the experimental part of this work (especially polymer coatings, phosphate films and DLC - type coatings). The wear evaluation of different types of coatings was performed with the aid of scanning electron microscopy after the tribological testing.
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Application reamers with cermet cutting edge and PVD rating
Lučaník, Aleš ; Plíšek, Jiří (referee) ; Kouřil, Karel (advisor)
The introductory part of this bachelor´s thesis provides definitions of basic accuracy parameters, quality of machined surface and requirements on accu- racy of holes. Further work describe the current technical level of available reaming tools of global manufacturers in terms of technological aspects, tool materials, tool geometry and the main structural elements. The final part deals with designing, implementing and evaluating an experimental verification of usable properties of prototypes newly developed reaming tools in collaboration with the company HAM-FINAL.
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Production of sleeper screw
Bartošek, Filip ; Štroner, Marek (referee) ; Lidmila, Zdeněk (advisor)
Bachelor thesis developed in the bachelor degrees addresses technological process of the production sleeper screw. The production uses technology volume thermoforming. The project was elaborated in cooperation with the company ŠROUBÁRNA KYJOV s.r.o. The screw will be made from material ČSN 11 503. This material is unalloyed construction steel with property of weld. Based on the literature study technology volume thermoforming was chosen tamping in closed instrument for the production of head screw. For the production of screw-thread was chosen technology of rolling. For the production head of screw was chosen horizontal fitting press machine. After the production there were used surfacing by galvanic zinc coating because of the better corrosion resistance.
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Application reamers with cermet cutting edge
Toman, Martin ; Plíšek, Jiří (referee) ; Kouřil, Karel (advisor)
This thesis deals with the technology of reaming aimed mainly on cermet reamers. In the introduction of the thesis, the basic parameters of precision, dimension tolerance, geometrical tolerance and surface roughness are shown. Also, the technology of reaming, parameters, geometry and sorting of the reaming tools is analyzed in depth. The overview of the world producers of reaming tools is also shown as a supplement. In the final part, an example of production optimization by replacing a reamer with a better performing one is shown. Experimental part of this thesis has been made in the cooperation with HAM-FINAL company.
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