Steam turbines

Cílem této bakalářské práce je popsat vývoj parních turbín, základní části parní turbíny a její typy. V teoretické části je popsána historie parní turbíny ve světě a České republice, dále princip parní turbíny, popis součástí v parní turbíně a různá zapojení parní turbíny. V praktické části jsou provedeny výpočty idealizovaného Rankin-Clausiova cyklu konkrétní parní turbíny.The goal of this bachelor thesis is to describe development of steam turbine basic parts of steam turbine and its types. In theoretical part there are described history of steam turbines in the world and Czech republic. Next one is principle of steam turbine, description of parts in steam turbine and different connection of steam turbine. In practical part there are calculations of ideal Clausius-Rankine cycle of specific steam turbine.

High-speed Condesing Steam Turbine

Cílem této diplomové práce je návrh dispozičního uspořádání malé třítělesové rovnotlaké turbíny s jedním regulovaným a jedním neregulovaným odběrem, výpočet průtočných kanálů všech stupňů, návrh a výpočet regulačních ventilů a vytvoření schémat zapojení turbíny a vzduchového kondenzátoru. Na začátku práce je uveden přehled výrobců parních turbín i s jejich unifikovanými produkty. Práce byla vypracována s podporou firmy G-Team, a.s. za použití výpočtů a pokynů uvedených v doporučené literatuře s podporou CFD simulací pro určení ztrátových součinitelů a FEA simulací pro určení vlastních kmitů lopatek.ith one controlled extraction and one uncontrolled extraction, calculation of the flow channel at all stage, design and calculation of the regulation valve and create connection diagram of steam turbine and air cooled condenser. At the beginning of this work is an overview of manufacturers of steam turbines and their unified products. Master thesis was developer with G-Team, a.s. as using calculations and the instructions given in the recommended literature with supporting CFD simulations to determine the loss coefficients and FEA simulations to determine the eigenfrequencies blades.

Development tendencies of work localization in Prague metropolitan region: suburbanisation of quarternary functions

Tato diplomová práce se zabývá vývojem lokalizace pracovních příležitostí v pražském metropolitním regionu a soustředí se na suburbanizaci kvartérních funkcí. Cílem předložené práce je analyzovat vývoj počtu pracovních příležitostí v jednotlivých částech pražského metropolitního regionu a zjistit, zda v pražském metropolitním regionu dochází k suburbanizaci kvartérních funkcí a zhodnotit významnost tohoto trendu ve smyslu počtu pracovních příležitostí v nových vědecko-výzkumných institucích. Mezi dílčí cíle diplomové práce je zařazeno zhodnocení struktury pracovních příležitostí ve vědecko-výzkumných institucích a zhodnocení potenciálu pro vznik propojení se soukromou sférou, které by mohlo vytvořit ekonomická centra nižšího řádu v zázemí pražského metropolitního regionu. Dalším dílčím cílem bylo zjistit, zda v souvislosti s novými vědecko-výzkumnými centry dochází ke změnám sociální struktury zázemí a ke zvýšení nároků na technickou, dopravní a sociální infrastrukturu. K analýze jsem použil data o pracovní dojížďce ze sčítání obyvatel z let 2001 a 2011, data o počtu zaměstnanců vědecko-výzkumných institucí ze Středočeského inovačního centra a dotazníkové šetření, které se uskutečnilo mezi zaměstnanci nových vědecko-výzkumných center lokalizovaných v zázemí pražského metropolitního regionu. V...This master's thesis deals with changes of work localization in Prague metropolitan region and concentrates on the suburbanisation of quarternary functions. Goal of the presented thesis is to analyze changes of work localization in different parts of Prague metropolitan region and discuss whether suburbanization of quarternary functions exists in Prague metropolitan region and evaluate its importance through the number of jobs in the new R&D institutions. Component goals include evaluation of the structure of jobs in new R&D institutions and evaluation of the potential for formation of cooperation with the private sector, which could lead to creation of new secondary economic centres in the periphery of the Prague metropolitan region. Other component goal finds out whether the existence of new R&D institutions can lead to changes in the social structure of the periphery and to the increased demand on social, technical and transportation infrastructure. For the purpose of analysis I used data on work commuting from 2001 and 2001 censuses, data on the number of employees in R&D institutions from the Central Bohemian innovation centre and questionnaire survey, which took place among the employees of new R&D institutions in the periphery of Prague metropolitan region. In the theoretical part I discuss...Department of Social Geography and Regional Develop.Katedra sociální geografie a region. rozvojeFaculty of SciencePřírodovědecká fakult

Skin effect in high-speed electrical machines.

Tato diplomová práce se zabývá potlačením vlivu skin a proximity efektu ve vysokootáčkových strojích. V první části jsou shrnuté obecné poznatky o vysokootáčkových strojích. Druhá část je věnována principu a možným potlačením důsledků způsobených skin a proximity efektem. Ve třetí části jsou ukázány výsledky simulací vytvořených modelů pro synchronní stroj s permanentními magnety. Na výsledcích těchto simulací je ukázán vliv skin a proximity efektu. Dále jsou navržena konstrukční opatření na omezení těchto a dalších nežádoucích jevů, aby bylo dosaženo co největší účinnosti.This master thesis deals with the suppression of the skin and proximity effects in high-speed machines. The first part summarizes the general knowledge of high-speed machines. The second part is devoted to the principle and possible suppression of consequences caused by skin and proximity effects. The third part shows the simulation results of models of a synchronous machine with permanent magnets. The results of these simulations reveal the consequences of skin and proximity effects. In addition, design measures are proposed to limit these and other undesirable phenomena to achieve the highest possible efficiency.

Silver ions increase plasma membrane permeability through modulation of intracellular calcium levels in tobacco BY-2 cells

ions increase plasma membrane permeability for water and small organic compounds through their stimulatory effect on plasma membrane calcium channels, with subsequent modulation of intracellular calcium levels and ion homeostasis. The action of silver ions at the plant plasma membrane is largely connected with the inhibition of ethylene signalling thanks to the ability of silver ion to replace the copper cofactor in the ethylene receptor. A link coupling the action of silver ions and cellular auxin efflux has been suggested earlier by their possible direct interaction with auxin efflux carriers or by influencing plasma membrane permeability. Using tobacco BY-2 cells, we demonstrate here that besides a dramatic increase of efflux of synthetic auxins 2,4-dichlorophenoxyacetic acid (2,4-D) and 1-naphthalene acetic acid (NAA), treatment with AgNO3 resulted in enhanced efflux of the cytokinin trans-zeatin (tZ) as well as the auxin structural analogues tryptophan (Trp) and benzoic acid (BA). The application of AgNO3 was accompanied by gradual water loss and plasmolysis. The observed effects were dependent on the availability of extracellular calcium ions (Ca2+) as shown by comparison of transport assays in Ca2+-rich and Ca2+-free buffers and upon treatment with inhibitors of plasma membrane Ca2+-permeable channels Al3+ and ruthenium red, both abolishing the effect of AgNO3. Confocal microscopy of Ca2+-sensitive fluorescence indicator Fluo-4FF, acetoxymethyl (AM) ester suggested that the extracellular Ca2+ availability is necessary to trigger the response to silver ions and that the intracellular Ca2+ pool alone is not sufficient for this effect. Altogether, our data suggest that in plant cells the effects of silver ions originate from the primal modification of the internal calcium levels, possibly by their interaction with Ca2+-permeable channels at the plasma membrane

Auxin transport at cellular level: new insights supported by mathematical modelling

The molecular basis of cellular auxin transport is still not fully understood. Although a number of carriers have been identified and proved to be involved in auxin transport, their regulation and possible activity of as yet unknown transporters remain unclear. Nevertheless, using single-cell-based systems it is possible to track the course of auxin accumulation inside cells and to specify and quantify some auxin transport parameters. The synthetic auxins 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene-1-acetic acid (NAA) are generally considered to be suitable tools for auxin transport studies because they are transported specifically via either auxin influx or efflux carriers, respectively. Our results indicate that NAA can be metabolized rapidly in tobacco BY-2 cells. The predominant metabolite has been identified as NAA glucosyl ester and it is shown that all NAA metabolites were retained inside the cells. This implies that the transport efficiency of auxin efflux transporters is higher than previously assumed. By contrast, the metabolism of 2,4-D remained fairly weak. Moreover, using data on the accumulation of 2,4-D measured in the presence of auxin transport inhibitors, it is shown that 2,4-D is also transported by efflux carriers. These results suggest that 2,4-D is a promising tool for determining both auxin influx and efflux activities. Based on the accumulation data, a mathematical model of 2,4-D transport at a single-cell level is proposed. Optimization of the model provides estimates of crucial transport parameters and, together with its validation by successfully predicting the course of 2,4-D accumulation, it confirms the consistency of the present concept of cellular auxin transport

The effect of biological and chemical additives on the chemical composition and fermentation process of Dactylis glomerata silage

This study was carried out to determine the chemical composition, silage quality and ensilability of ten cocksfoot cultivars using biological and chemical silage additives. The plant material was harvested from the first and second cut, cultivated at the Research Station of Fodder Crops in Vatín, Czech Republic. Wilted forage was chopped and ensiled in mini-silos with 3 replicates per treatment. The treatments were: 1) without additives, used as a control; 2) with bacterial inoculants; and 3) with chemical preservatives. The results indicated that the year factor (2012-2013) influenced significantly the chemical composition of the silage in both cuts. The use of biological inoculants reduced the content of crude fibre and acid detergent fibre; but it did not influence the content of neutral detergent fibre, in comparison with the control silage in both cuts. Furthermore, the application of biological inoculants reduced the concentration of lactic acid (LA) and acetic acid (AA) in contrast to the control silage in the first cut. Moreover, in the second cut the same values tended to be the opposite. Interestingly, ‘Amera’ was the unique variety that presented a high concentration of butyric acid (0.2%) in comparison with other varieties in the first cut. In conclusion, the biological inoculants had a favourable effect on silage fermentation. Notably, only ‘Greenly’ and ‘Starly’ varieties from the first cut; and ‘Greenly’, ‘Sw-Luxor’, and ‘Otello’ varieties from the second cut were appropriate for ensiling because their pH-values; LA and AA concentrations were ideal according to the parameters of the fermentation process

Non-steroidal anti-inflammatory drugs target TWISTED DWARF1-regulated actin dynamics and auxin transport-mediated plant development

The widely used non-steroidal anti-inflammatory drugs (NSAIDs) are derivatives of the phytohormone salicylic acid (SA). SA is well known to regulate plant immunity and development, whereas there have been few reports focusing on the effects of NSAIDs in plants. Our studies here reveal that NSAIDs exhibit largely overlapping physiological activities to SA in the model plant Arabidopsis. NSAID treatments lead to shorter and agravitropic primary roots and inhibited lateral root organogenesis. Notably, in addition to the SA-like action, which in roots involves binding to the protein phosphatase 2A (PP2A), NSAIDs also exhibit PP2A-independent effects. Cell biological and biochemical analyses reveal that many NSAIDs bind directly to and inhibit the chaperone activity of TWISTED DWARF1, thereby regulating actin cytoskeleton dynamics and subsequent endosomal trafficking. Our findings uncover an unexpected bioactivity of human pharmaceuticals in plants and provide insights into the molecular mechanism underlying the cellular action of this class of anti-inflammatory compounds