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Dissertations / Theses on the topic 'Vruby'
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1
Bittner, Jiří. "Srovnávací analýza napětí součástí s vruby pomocí fotoelasticimetrie a MKP." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228090.
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The diploma thesis deals with comparative analysis of stress and strain of notched machine parts using photoelasticity and finite element method (FEM). Experimental and numerical comparative analyses were performed on three models: hook, J shaped bracket and 3-point bending beam with notch. Equivalent stresses, principal stresses and its directions were analyzed. The emphasis is given on photoelasticity, the theory and principles of photoelasticity are described in more detail. FEM analysis was performed using software ANSYS 11. The work presented includes the preparation of polariscope in the laboratory of Institute of machine and industrial design in order to use it in tutorials focused on experimental stress analysis using photoelasticity.
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Kozáková, Kamila. "Vliv vrubů při cyklickém vysokofrekvenčním únavovém zatěžování." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443717.
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The diploma thesis deals with the evaluation of the lifetimes of smooth and notched specimens. The comparison of their lifetimes is focused on the case of high-frequency cyclic loading in the area of high-cycle and gigacycle fatigue of materials. The theory of critical distances is used to evaluate and recalculate the life curves of the notched specimens. The effect of the notch is quantified using the Line method. The critical length parameter is determined so that the life curve of the notched specimens corresponds to the curve measured on smooth specimens. The result is the dependence of the critical length parameter on the number of cycles to fracture. Knowledge of critical length parameters can be used to determine the lifetime of notched specimens as well as real notched components using the results of fatigue tests of smooth specimens.
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Krepl, Ondřej. "Napjatost v okolí velmi ostrých bimateriálových vrubů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230865.
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Presented diploma thesis is concerned with problems of a stress singularity exponent and a generalized stress intensity factor determination, by dint the stress field in the vicinity of the stress concentrator can be consecutively determined. This task is possible to sectionalize into three parts. The first part summarizes basic information about linear anisotropic materials, deals with fundamentals of the linear elastic fracture mechanics and introduces its generalization to the case of the generalized stress intensity factors. The second part is dedicated to a special theory of anisotropic elasticity - Lekhnitskii-Eshelby-Stroh formalism (LES). Furthermore, a theory of the psi-integral is introduced, by dint the stress intensity factor is determined. The final part applies the LES theory and the psi-integral to the concrete material configuration of a crack on the bimaterial interface, a special example of a sharp bimaterial notch. By means of analytical-numerical algorithm in ANSYS and Silverforst FNT95 software the stress singularity exponents and generalised stress intensity factors are consecutively computed.
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Svoboda, Petr. "Popis rozložení napětí v okolí ostrého vrubu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382552.
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The presented diploma thesis deals with the problem of determining the stress singularity exponent of the V-notch. This task can be divided into two parts. The first deals with the theoretical background, that means the basic relations of mechanics and the basic concepts of fracture mechanics. The second part deals with the elaboration of the Williams method and the creation of a program for calculating the stress singularity exponent.
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Kopp, Dalibor. "Stanovení podmínek porušení bi-materiálových vrubů při kombinovaném módu zatížení." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229718.
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In the range of linear elastic fracture mechanics, the conditions for critical loading assessment of structures made of two dissimilar materials are usually based on the assumptions of prevailing normal mode of loading. The same assumption is usually applied to the stability criterion of bi-material notches. However, in engineering practice there are cases of loading and failure closed to the shear mode. The aim of the work is the assumption of the stability criterion of bi-material notches subjected to combination of normal and shear loading. The FEM model of the bi-material notch under combination of normal and shear loading mode is created and solved and evaluated as well.
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Hrstka, Miroslav. "Popis rozložení napětí v okolí bimateriálového vrubu pomocí zobecněného faktoru intenzity napětí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230355.
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The presented diploma thesis deals with a problem of a generalized stress intensity factor determination and a consecutive study of stress distribution around the bimaterial notch tip, combining analytical and numerical methods. This task is possible to sectionalize into three parts. The first part is dedicated to the fundamentals of the linear fracture mechanics and the mechanics of composite materials. The second part deals with methods of anisotropic plane elasticity solution. Pursuant to the solution the computational models in the third part are created. The first model makes for determination of a singularity exponent eigenvalue by dint of Lekhnitskii-Eshelby-Stroh formalism. The second model makes for determination of the generalized stress intensity factor using psi-integral method, which is based on the Betti reciprocal theorem. All needed calculation are performed in the software ANSYS 12, Maple 12 and Silverforst FTN95. Results will be compared with the values obtained from a direct method of the generalised stress intensity factor determination.
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Štegnerová, Kateřina. "Aplikace zobecněné lineárně elastické lomové mechaniky na odhad počátku šíření trhliny z ostrého V-vrubu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230773.
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The master thesis is focused on estimation of crack propagation origin from sharp V-notch. Stress distribution around the tip of the V-notch is described on the base of generalized linear elastic fracture mechanics. The change of the stress singularity exponent caused by geometry of the V-notch and the vertex singularity is taken into account. The first part of the work is devoted to the estimation of the stress singularity exponent of the V-notch either from stress distribution around the tip of the V-notch or by using analytical solution. Formerly derived stability criteria are applied in the second part of the work. The origin of the crack propagation is estimated for several experimental specimens. The aim of this thesis is to compare the available experimentally observed data with results obtained using those criteria based on the application of generalized linear elastic fracture mechanics developer at the Institute of Physics of Materials Academy of Sciences of the Czech Republic. The finite element code Ansys and mathematical software Matlab were used for the necessary calculations.
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Ščotka, Martin. "Vliv koncentrace napětí ve vrubu na napjatost a deformaci na čele trhlin zatížených ve smykových zátěžných módech." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318836.
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This diploma thesis deals with influence of a notch on stress-strain states at the front of cracks by shear modes. Starting with fracture mechanics and its division, followed by stress intensity factor and calculate its by finite element method. Calculation is solved for two types of notches, U-notched and V-notched, both notches were modeled parametrically so their geometry was changeable and stress intensity factor were calculated for all configurations. Subsequently was solved next calculation of stress intensity factor but for shaft without notch. Finally, was evaluated influence of notch on stress intensity factor. Software for finite element method has been used ANSYS. Others calculation was provided in software MATLAB
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Havránková, Zuzana. "Návrh expozice mokřadních biotopů v Arboretu FLD v Kostelci nad Černými lesy." Master's thesis, Česká zemědělská univerzita v Praze, 2016. http://www.nusl.cz/ntk/nusl-257810.
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This thesis deals with design of a new trees exposure in the arboretum in Kostelec nad Černými lesy, where model of wetland habitats will be created. Emphasis is placed on the supplement autochthonous species especially willow - Salix.
A literature review provides information about Arboretum Kostelec nad Černými lesy and compositional principles. It is focused on wetlands, floodplain forest and it is willow communities. Thesis includes the characteristic of the area and it's natural conditions.
Inventory of area were made in the practical part. Botanical survey detect current vegetation cover. The area of interest was evaluated from the botanical point of view. Evaluation of the health condition of trees was done to improve the condition of existing vegetation and habitat model layout. Treatment and the existing vegetation felling, was proposed. Map outputs of the research were processed in ArcGIS 10.1. Exposure design was drawn in AutoCAD 2016. List of recommended trees that is based on analysis of Czech and foreign sources was created. Pathway and information system for visitors that use the QR code was designed.
The results of this thesis can be applied in practice in Arboretum Kostelec. Model of wetland habitats can be used for research and educational purposes.
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Korbel, Jakub. "PORUŠOVÁNÍ SLOŽENÝCH TĚLES VYVOLANÉ MATERIÁLOVOU NESPOJITOSTÍ." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-234029.
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This Ph.D. thesis deals with modeling of compound structures containing defects such as cracks or notches. Attention was mainly focused on structures manufactured out of metals and polymers. Presented results were obtained from experimental measurements, which were compared with theoretical estimations of the ultimate states of the compound structures. Theoretical estimations were obtained by the application of the generalized fracture mechanics, whose integral part is based on numerical solution provided by finite element method. The results of the Ph.D. thesis contribute both to prediction of the limit states of compound objects, and to verification of the validity of the generalized fracture mechanics.
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Kolářová, Eva. "Vliv přídavku vícesměrně orientované výztuže na mechanické vlastnosti materiálu pro přípravu celkově snímatelných náhrad." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2014. http://www.nusl.cz/ntk/nusl-217087.
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Tato Diplomová práce se zabývá vlivem vyztužení na mechanické vlastnosti materiálu pro přípravu snímatelných náhrad. Pro testování byly použity tři sady vzorků: PMMA pryskyřice, PMMA pryskyřice s Dentapreg Mesh výztuží a PMMA pryskyřice vyztužena zesilující síťkou z nerezové oceli.Pro měření chování vzorků při statickém a dynamickém namáhání byl použit třibodový ohybový test a Charpy rázové kladivo. Viskoelastické vlastnostzi byly měřeny dynamicko-mechanickou analýzou (DMA). Skenovací elektronová mikroskopie (SEM) byla použita k charakterizaci lomových ploch. Během statického namáhání vzorků výztuž nehraje důležitou roli v porovnání s nevyztuženou pryskyřicí. Nicméně byl pozorován opačný trend při dymanickém namáhání, kde efekt výzruže rostl v řadě PMMA pryskyřice – síťka z nerezové oceli – Dentapreg Mesh.
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Krepl, Ondřej. "Speciální problémy lomové mechaniky singulárních koncentrátorů napětí v kompozitních materiálech." Doctoral thesis, Vysoké učení technické v Brně. CEITEC VUT, 2018. http://www.nusl.cz/ntk/nusl-371930.
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Předkládaná disertace se zabývá obecnými singulárními koncentrátory napětí a to zejména ostrým vrubem neboli V-vrubem, ostrým bi-materiálovým vrubem a ostrou materiálovou inkluzí. V první části práce je stručně nastíněna Kolosovova-Muschelišviliho teorie komplexních potenciálů rovinné pružnosti aplikovaná na problémy lomové mechaniky. Dále je diskutována lineární elastická lomová mechanika trhlin, V-vrubů, bi-materiálových vrubů a bi-materiálových spojů. V rešerši jsou dále zahrnuta kritéria směru iniciace trhliny i její stability a to kritérium maximálního tečného napětí, faktor hustoty deformační energie a sdružené napěťově-energetické kritérium. Následují text uvádí omezení jednoparametrové lomové mechaniky a výhody její multiparametrové formy. Další část představuje metody pro určení nezbytných parametrů pro popsání pole napětí a posuvů v blízkosti obecného singulárního koncentrátoru napětí. Tyto parametry zahrnují vlastní číslo a zobecněný faktor intenzity napětí. Vlastní číslo je určeno jako řešení problému vlastních hodnot zatímco metody pro určení zobecněného faktoru intenzity napětí tvoří Psi-integrál a metoda přeurčitosti. Obě zmiňované metody jsou aplikovány na zde studované obecné singulární koncentrátory napětí a vzájemně porovnány. Kritéria pro vznik trhliny v obecném singulárním koncentrátoru napětí jsou navržena. V rámci numerických příkladů jsou předpovězeny směry iniciace trhliny a podmínky stability pro konkrétní problémy. Kritické síly pro V-vrub jsou předpovězeny pomocí výše zmíněných kritérií a srovnány s experimentálními daty v literatuře. V následující části jsou ukázány metody analýzy multi-materiálového problému. V závěru práce jsou shrnuty způsoby iniciace a šíření trhliny v blízkosti ostré materiálové inkluze.
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Hrstka, Miroslav. "Evaluation of Fracture Mechanical Parameters for Bi-Piezo-Material Notch." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399212.
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Předkládaná dizertační práce se zabývá stanovením hlavních členů Williamsova asymptotického rozvoje popisujícího rovinné elektro-elastické pole v okolí piezoelektrických bi-materiálových vrubů a trhlin na rozhraní za použití rozšířeného Lechnického-Eshelbyho-Strohova formalismu v návaznosti na čistě anizotropní pružnost. Je ukázáno, že rozšířený Lechnického-Eshelbyho-Strohův formalismus představuje spolu s moderními programovacími koncepty v jazyku Python efektivní a také praktický nástroj pro lomovou analýzu piezoelektrických bi-materiálů. Teoretická část práce popisuje aspekty anizotropní pružnosti a její návaznost na piezoelektrické materiály. Základní rovnice zaměřené na speciální typy monoklinických materiálů, které umožňují oddělení rovinného a anti-rovinného problému, jsou vyjádřeny pomocí komplexních potenciálů. V praktické části práce je sestaven problém vlastního hodnot pro bi-materiálový vrub, na jehož základě jsou stanoveny exponenty singularity a pomocí dvoustavového -integrálu také zobecněné faktory intenzity napětí. Veškeré vztahy a numerické procedury jsou následně rozšířeny na problém piezoelektrických bi-materiálových vrubů a podrobně prozkoumány v uvedených příkladech. Zvláštní pozornost je věnována přechodu asymptotického řešení téměř zavřených vrubů a trhlin na rozhraní. Vliv směru polarizace na asymptotické řešení je také zkoumán. Přesnost stanovení zobecněných faktorů intenzity napětí je testována srovnáním asymptotického řešení a řešení získaného pomocí metody konečných prvků s velmi jemnou sítí konečných prvků. Na závěr je formalismus modifikován pro nepiezoelektrické materiály.
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Štegnerová, Kateřina. "Popis šíření trhlin v polích silně nehomogenních a reziduálních napětí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399210.
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This Ph.D. thesis was written under the supervision of Assoc. Prof. Luboš Náhlík, Ph.D. and Assoc. Prof. Pavel Hutař, Ph.D. Thesis is focused mainly on application of generalized linear elastic fracture mechanics, which allows description of crack behaviour propagating from general singular stress concentrators, such as material interfaces or sharp V-notches, and verification of validity of used fracture criteria. The obtained results were used in the next part of the thesis, which deals with the issue of crack propagating in ceramic composites, where the stress distribution field is strongly influenced by the existence of material interface and presence of residual stresses, that arise during manufacturing process of composite.
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Slabyhoudová, Zuzana. "Canterburské povídky v českém překladu Františka Vrby: lingvistická analýza." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-328781.
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The diploma thesis offers a philological analysis of František Vrba's translation into Czech of The Canterbury Tales by Geoffrey Chaucer. The paper is composed of three major parts: "Theoretical background", "Hypothesis and Method", and "Analysis". The analysis addresses matters of lexical, syntactic, stylistic, metrical and cultural nature. The analysis focuses on The Knight's Tale, The Miller's Tale, The Nun's Priest's Tale and The Wife of Bath's Tale as convenient manifestations of stylistic variation, cross-generic links and structural correspondences and contrasts in The Canterbury Tales. The aim of this thesis is to analyze and evaluate the quality of František Vrba's Czech translation.
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Tyl, Tomáš. "Analýza variability vybraných fyzikálních vlastností dřeva vrby z lužního lesa." Master's thesis, 2009. http://www.nusl.cz/ntk/nusl-86567.
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Vraštil, Jiří. "Analýza variability vybraných mechanických vlastností dřeva vrby z lužního lesa." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-88661.
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Svobodová, Iveta. "Generativní šíření vrby bílé (Salix alba L.) v oblasti střední novomlýnské nádrže." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-91822.
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Petrášková, Radka. "D.H. Lawrence - Milenec lady Chatterleyové v překladu S. Jílovské a F. Vrby." Master's thesis, 2007. http://www.nusl.cz/ntk/nusl-289876.
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This thesis attempts to explore the role of the translator's gender in the two translations of D. H. Lawrence's novel Lacfy Chatterlry's Lover. Within the limited context of an M.A. thesis, the writer submits the following: 1. A biography of D. H. Lawrence and a short overv1ew and periodization of his extensive work. 2. An exploration of the position of D.H. Lawrence among his contemporaries together with an attempt to determine his position in the context of the modernist movement and other literary streams and of his life and of the previous epoch. 3. A short overview of D. H. Lawrence's individual philosophy, his attitude to and understanding of women and men women relationships and the reflection of these views in Lawrence's work. An exploration of Lawrence's fiction of women and his fiction woman's experience of physical love is included. 4. An overview of the genesis of D. H. Lawrence's novel Lacfy Chatteriry'J Lover, including a factual appraisal of previous versions and an account of its content. A more comprehensive coverage of the topic follows, including an account of the reception of D. H. Lawrence's work in Great Britain and in the USA, and of Lacfy Chatterlry'.r Lover in particular, as well as Lawrence's clash with censorship. There is an examination of the early reception of Lawrence's work...
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Boučková, Monika. "Arachnofauna dutin hlavatých vrb." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-427828.
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The aim of this dissertation "Arachonofauna cavities of the head willows" was to find a cavity fauna that inhabits willow trees and point out the pollarding of willow trees as a suitable management for the formation of cavities. The chosen location for this research was Vojkovice near Židlochovice, where during the years 2018 – 2019 were examined 21 willow trees with the help of newspaper traps. Traps were always exchanged at monthly intervals. A total of 72 spiders were found, of which only 10 were adults. The most important finding of this work is the discovery of Midia midas (Simon, 1884), which represents a typical inhabitant of hollow fauna and is a highly endangered species. This finding indicates that willow cavities are also a refuge for rare species. Juvenile individuals were most represented in the Gnaphosidae family of 20 pieces. Most of the spiders found were synanthropic species, so they are close to humans.
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Hlavatá, Barbora. "Posouzení revitalizace na toku Potůček." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-90021.
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Hrouz, David. "Postupy homogenizace pojistného kmene." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-191277.
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This diploma thesis deals with transferring the risk of a insurance company to another subject. The basic requirement is to homogenize the selected insurance portfolio. The amount of capital required is determined by identifying and quantifying the risk. Adjusted indicator of Economic value added (EVA) determines the optimal ratio of the retention and the risk transferred. There are several factors that can affect the amount of the retained risk. The main objective is to determine the amount of the optimal retention itself and select the appropriate type of reinsurance. The recommendation is based on the current development of expenses on insurance claims.
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VOLF, Martin. "Vliv obranných mechanismů vrb na strukturu společenstev herbivorního hmyzu." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-136604.
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This study examines the role of deffensive host-plant traits in structuring the community of leaf-chewing insects living on willows. Host-plant phylogeny was reconstructed and leaf morphology and content of three different groups of secondary metabolites were measured. Relationships between defensive leaf traits were examined and their influence on insect community structure was analyzed.
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CHRT, Vladimír. "Vliv genotypu, stanoviště a agrotechniky na produkci fytomasy vybraných energetických dřevin." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-203380.
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This diploma thesis deals with the cultivation of fast-growing wood and concentrates on the influence of particular factors like e.g. location, agrotechnology and fertilizers, which have a crucial impact on the phytomass production. Moreover, the thesis evaluates the economic efficiency of this type of sustainable energy ressource, which can be a source of local business. Introductory theoretical chapters describe essentials rules of the cultivation of fast-growing wood. Furthermore the thesis presents general information in this field and proposes suitable wood clones. In addition, the thesis outlines the process of choice and preparation of the agricultural parcel, the usage of various fertilizes, herbicides and agrotechnology. The applied core characterises the business case itself. The primary research compares financial investment and its return of two examined agricultural parcels under the prerequisit of suitable choice of location and agrotechnology. A trail phase depictes the cultivation of fast-gworing wood and discuss presumptions for succesfull business. This thesis is mainly based on primary research. The acquired data are further analyzed and the final chapter attempts to outline the results and suggest measures.
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Kuchár, Michal. "Vliv duální mykorhizy na příjem těžkých kovů vybranými dřevinami čeledi Salicaceae." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-301856.
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3.2. Abstract Soil contamination by heavy metals represents rather serious environmental problem for both human health and an environment itself. One of the perspective technologies dealing with this threat that only recently has been intensely developed is phytoremediation by means of short rotation coppice plantations. As plants used in this technology (mostly poplars and willows) host two major groups of mycorrhizal fungi substantially influencing plant physiology it is important to study plant-mycobiontheavy metals interactions rather than just plant-heavy metals interactions. The present thesis aimed to contribute to the growing knowledge of the field by search for suitable mycobionts of poplar or willow tolerant to heavy metals, by evaluating an activity of the key antioxidative enzyme in selected mycobionts and by looking at physiological responses of plant hosts to their mycobionts in a soil polluted by heavy metals. The first experiment in vitro focused on screening of morphometric criteria of fungi growing on solid growth media amended with mixture of heavy metals. Based on the results, several tolerant ectomycorrhizal strains were chosen for the next inoculation of fast growing trees serving phytoextraction and phytostabilisation strategies. The second, re-synthetic experiment was conducted in...