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Temperature regime of forest soils
Dohnal, M. ; Votrubová, J. ; Mazúchová, R. ; Blunár, P. ; Tesař, Miroslav
Contribution deals with the monitoring of the temperature regime of forest soils and the soil heat flux at small mountainous basins Liz in the Šumava Mts. and Uhlířská in the Jizera Mts. Soil temperatures are measured with the help of soil moisture meters (Pt100 at Liz basin and CS107 at Uhlířská basin), the soil heat flux is measured with the use of the sensor Hukseflux HFP01. Measured results were statistically evaluated, the analysis of the consistence of the measurement was done and cumulative soil heat fluxes were calculated for the individual hydrological years.
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The Use of New Knowledge about Generation Y for Their Inclusion into Business Practice
Kruntorádová, Markéta ; Dobřický, Josef (referee) ; Dohnal, Mirko (referee) ; Dohnalová, Zuzana (referee) ; Mikulec, Luděk (advisor)
Dissertation deals with Generation Y and its position in the corporate environment and in the labor market. The selected issue is very topical because of increasing structural and cyclical unemployment among young people. In preparing the dissertation, we departed from theoretical findings acquired by studying Czech and foreign monographs, articles published in journals, other electronic resources and, most importantly, primary research conducted. The main objective of the dissertation to gain new knowledge about Generation Y, which would lead to a more effective inclusion of young people (especially graduates) into practice with the use of new management methods in the adaptation and stabilization of a young employee in the job, with focus on future employees with economic expertise. In order to achieve the main objective, 4 sub-objectives and 4 research questions with relevant hypotheses were set. Based on an analysis of the theoretical basis and secondary data, a schema of adaptation and stabilization of a young employee was created. The primary research conducted then combines quantitative and qualitative approaches for the analysis and description of each part. The research results are presented in the form of partial conclusions characterizing each area as well as in the form of a summarizing conclusion placed in a broader context in a comparison with the determined state of current scientific knowledge. The dissertation includes contributions to science and research, business practice and teaching as well as a proposal of continuation of research activities.
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Computational analysis of fluid flow in a tumble dryer
Dohnal, Miloslav ; Juřena, Tomáš (referee) ; Hájek, Jiří (advisor)
The aim of this work is to create a computational model of radial industrial tumble dryers, to calculate and identify the amount of air that flows through the inside of the drum itself. The calculation will be performed via computational fluid dynamics (CFD). Furthermore, compile transient balance model of mentioned dryers. Perform simulation balance model and compare the results of simulations with experimental measurements. By comparing the experimental data and simulation to determine the degrees of freedom of balance model and evaluate their impact on the assembled transient model. For a better understanding of the drying process, there is constructed a system of differential equations describing heat and moisture within the material being dried on a simple model. In the section devoted to the computational analysis of fluid flow is analyzed existing geometry of the drum, which has a major impact on the flow of air inside the drum itself. Following describes how to simplify its complex geometry entering the computational fluid dynamics. Then, there is carried out a simulation of fluid flow inside the tumble dryers using MRF and Sliding Mesh models. Finally, there is an analysis of the data obtained and determined the average amount of air flowing through the drum itself. On the contrary, the aim of the work is not to create another text tool for students engaged in CFD theme.
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Porous elements based on granular materials and inorganic binders
Bulejko, Pavel ; Dohnal, Mirko (referee) ; Svěrák, Tomáš (advisor)
Tato diplomová práce zkoumá možnosti tvorby porézních struktur za použití partikulárních materiálů pojených anorganickými pojivy bez dodatečné tepelné úpravy vypalováním. Jako základní pojiva byly použity portlandský a hlinitanový cement a pojiva na bázi alkalicky aktivovaného metakaolinu (geopolymeru). Jako základní kamenivo byl použit karbid křemíku v různých frakcích podle velikosti částic. Byly taktéž použity další zrnité materiály, např. křemenný písek anebo odpadních materiálů (mleté sklo a porcelán) roztříděných do frakcí podle velikosti částic. Byl sledován vliv složení a množství kameniva na vytváření porézní struktury a tím i na mechanické vlastnosti, které byly testovány pomocí mechanických zkoušek. Pevnostní zkoušky byly provedeny na trámečcích 20 × 20 × 100 mm připravených z testovacích směsí. Granulometrické a fázové složení vstupních surovin bylo studováno metodou laserové granulometrie resp. RTG difrakce. Porézní struktura byla studována metodami rtuťové porozimetrie, dále pomocí světelné a rastrovací elektronové mikroskopie a taktéž pyknometrickou metodou. V rámci charakterizace přepážek (terčíky o průměru 90 mm) připravených z jednotlivých materiálů bylo provedeno stanovení efektivní permeability průtokem vzduchu. Dále byly provedeny testy vzlínavosti kapaliny v připravených materiálech. V závěru práce byly provedeny pokusy o filtraci jemných suspenzí přes uvedené přepážky.
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Acoustical analysis of mechanical watsches
Dohnal, Marek ; Balík, Miroslav (referee) ; Sigmund, Milan (advisor)
This thesis is focused on the analysis of the characteristics of mechanical watches on the basis of their sound. There are theoretically analysed usual mechanical defects and disorders of watches and compensation of those defects. Particular attention is given to disorders, that can be extracted from the recorded acoustic sound of watches. There are also solved most appropriate methods of recording with a respect to the minimisation of ambient acoustic interference. The main part of this work is experimental measurement on watches and evaluation of achieved acoustic data. For this purpose, an autonomously running software were developed.
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Separation of gaseous pollutants on membrane contactors
Ostrezi, Jan ; Dohnal, Mirko (referee) ; Svěrák, Tomáš (advisor)
The diploma thesis is devoted to the separation of a gasseous pollutant (CO2) from a gas mixture using an experimental technology device - membrane contactor. The theoretical part is mostly focused on the recent progress in the field of membrane contactors. The theoretical part also contains theory of absorption, which is needed to understand the subject properly. The experimental part focuses on the construction of the experimental device. The efficiency of the device in absorption of carbon dioxide to an aqua solution of sodium hydroxide was tested. At the end, experimental data are discussed.
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MULTI-OBJECTIVE OPTIMIZATION OF SCIENCE PARKS BASED ON QUALITATIVE EQUATIONLESS RELATIONS
Wouters, Hana ; Koráb, Vojtěch (referee) ; Hřebíček, Jiří (referee) ; Čapek, Jan (referee) ; Dohnal, Mirko (advisor)
Tato dizertační práce řeší optimalizaci vědeckých parků z hlediska potřeby zvyšování konkurenceschopoností regionů a potažmo celé ČR. Je koncipována pro investory, kteří chtějí realizovat projekt VP v různých regionech ČR nebo manažery již existujících vědeckých parků, kteří chtějí udělat další rozhodnutí. Možnost realizovat projekt VP platí pro všechny regiony, včetně regionů, které se dříve mohly spoléhat na dostupnost a těžbu nerostných surovin (tradičně těžba uhlí), jež v minulosti fungovala jako významný faktor pro rozvoj průmyslu a ekonomické aktivity. Tyto regiony se nyní musejí vyrovnat se ztrátou konkurenceschopnosti a přesunout své úsilí do oblasti rozvoje výzkumu a vývoje produkujícího inovace. Kvalitativní modelování je vhodné pro tak málo známé a komplexní systémy jako jsou právě vědecké parky (VP). Modely vědeckých parků obsahují proměnné různého charakteru a různých časových chování. Z tohoto důvodu jsou studovány rychlé a pomalé modely. Pro 11 pomalých proměnných je studován soubor 17 kvalitativních bezrovnicových vazeb typu (např. kvalita výzkumných a vývojových inženýrů, konkurenční status atd.) společně se souborem 14 kvalitativních bezrovnicových vazeb pro 10 rychlých proměnných typu (např. spolupráce mezi průmyslem a akademickými ústavy, výměna průmyslových informací apod.). V této dizertační práci jsou prezentována řešení rychlých a pomalých modelů ve formě souborů rychlých a pomalých scénářů a přechodů mezi nimi a jsou hledána optimální řešení. Analýza/optimalizace málo známých, nelineárních, multidimenzionálních systémů jako jsou vědecké parky je složitá a je obtížné vytvořit smysluplné a dostatečně přesné modely nestabilního chování. Systematická analýza řady kvalitativních řešení je hlavní částí disertační práce a jejím hlavním vědeckým přínosem. Jednotlivé kroky postupu tvorby modelu jsou názorně ilustrované na příkladech. Text obsahuje interpretaci dosažených výsledků a formulaci přínosů pro teorii a praxi.
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R&D support: the way how to increase enterprises’ competitiveness
Bočková, Nina ; Dohnal, Mirko (referee) ; Duspiva, Pavel (referee) ; Motyčková, Monika (referee) ; Meluzín, Tomáš (advisor)
This dissertation investigates the possibilities of increased use of direct and indirect support for R&D in small and medium-sized companies operating in branches of the manufacturing industry in the Czech Republic and specialising in the production of computers and electronic and optical instrumentation and equipment. The choice of the topic of this work was motivated by personal experience in a field in which companies either have not had enough information to take advantages of subsidies for research and development or have had negative experience relating to applications for direct support for research and development. These facts have presented obstacles to the realisation of research and development in corporate practice. The aim of this dissertation is to propose a methodology for the use of available tools in support for research and development in the Czech Republic and its verification against real data from selected companies. Data from primary and secondary research was used to investigate the selected area of academic knowledge. A questionnaire investigation was performed on the basis of knowledge obtained from detailed research of Czech and foreign literary sources. The respondents were companies in the electronic industry. The dissertation presents the results of empirical research and an assessment of research questions relating to a comparison of a selected sample of companies actively realising research and development with companies engaged merely in production with no innovative processes. On the basis of questionnaire processing and the testing of research questions, a methodology was created for small and medium-sized companies with the use of fuzzy logic facilitating decision-making in the financing of research and development activities with the use of direct and indirect support. Use of the proposed methodology will allow companies to expand sources of financing for the innovation process as an essential part of the competitive battle in the industry in question. The methodology is a significant aid for strategic decision-making in small and medium-sized companies considering the introduction of research, development and innovation. Benefits of this dissertation can be seen not merely on the theoretical and practical level, but also in the area of education.
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Systematic Solution for Information Security in Organisation
Palička, Jan ; Dohnal, Matěj (referee) ; Sedlák, Petr (advisor)
This diploma thesis deals with ISMS implementation in Netcope Technologies, a. s., which is involved in the production of network cards for high speed acceleration. This thesis is divided into two logical parts. In the first part the theoretical basis information is presented, including selected methods for implementing information security. In the second part, the analysis of the company and the proposed measures are presented.
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Analysis of Flow Distribution in Systems with Dense Tube Bundles
Babička Fialová, Dominika ; Dohnal, Miloslav (referee) ; Turek, Vojtěch (advisor)
Considering heat transfer equipment with dense tube bundles, it is essential to ensure as uniform a fluid distribution into the tubes as possible in order to prevent various operating problems. This bachelor’s thesis therefore focuses on tube-side flow analysis in such equipment. CFD simulations were carried out using a diverse set of flow systems with outflow into a constant-pressure environment. The respective tube bundle geometries differed in densities and sizes, arrangements of the tubes, and tube diameters. Air was used as the working fluid in the majority of the cases, however, some of the simulations were also carried out with water. Data obtained from evaluations in the fluid flow modelling software ANSYS Fluent were further analysed and the influence of the mentioned differentiating parameters on flow distribution non-uniformity and pressure drop was investigated. According to the regression model, the dependence of flow distribution non-uniformity on density and size of the bundle and on mass flow rate per unit outflow area cannot be rejected with the standard significance level. As for pressure drop, the only parameter that was not rejected was mass flow rate per unit outflow area.
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