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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
381

Analýza radiálních kluzných ložisek s využitím pokročilých výpočtových metod / Radial Slide Bearing Analysis Using Advanced Computational Methods

Orbán, Tomáš January 2017 (has links)
This master’s thesis introduces a slide bearing analysis using the MBS software tool of FEV Virtual Engine, including real surface topography based on 3D roughness measurements. The first half of the thesis gives a brief overview about gasoline combustion engines, slide bearing usage in engines, slide bearing construction and about essential approaches for the characterization of elasto-hydrodynamic behavior. In the second half, the process of model building, rough surface measurement and preparation of analyses are described. At the end of this thesis, the results of the analyses are shown and discussed.
382

Analýza možností realizace nové stanice 400/110kV jako náhrady za TR Tábor / The Analysis of the Possibility of Realization of a New Substation 400/110kV as a Substitute for TR Tábor

Modlitba, Petr January 2017 (has links)
This thesis deals with the assessment of the location of the new transformer station 400/110 kV in terms of conditions in the 110 kV network, which will be supplied from this substation. The new 400/110 kV transformer station will replace the current transformer station 220/110 kV Tábor, which will be decommissioned in connection with the overall 220 kV system attenuation in the Czech power transmission system. On the basis of the load flow simulation of the 110 kV distribution network and calculations of the short-circuit conditions performed by simulation SW LUG two variants of the location of a new 400/110 kV transformer station were assessed. The 110 kV network calculations were focused on the evaluation of voltage conditions, the 110 kV lines loading in the standard operating scheme and in failure states according to the N-1 criterion, short-circuit conditions and losses. On the basis of the computational analyses, the technical measures necessary to ensure the reliable operation of the 110 kV network in the given area are designed and economically evaluated.
383

Návrh rekonstrukce části distribuční NN sítě včetně zpracování projektové dokumentace k provedení stavby / Design of reconstruction the part of the LV distribution network including make the creation of Detail Design Documentation

Kubeša, Radek January 2019 (has links)
This master’s thesis deals with problems associated with the design of LV distribution networks. In the theoretical part there are described, legislative requirements for the designer of distribution networks, overwiev of standards in which the designer should have oriented and programs used in practice to create design documentation. In the next part there are given requirements for the detail design documentation. Practical part of master’s thesis is devoted to design of reconstruction of distribution network in the given part of village. Appraisal of existing a newly design distribution network was done by calculating of stady state in the BIZON program. In the last part there is listed design documentation for construction in range for the smooth implementation of the project.
384

Výpočet sedání výškové budovy s využitím metody konečných prvků / Prediction of foundation settlement of high-rise building using the finite element method

Červenka, Jan January 2020 (has links)
The focus of this thesis is to deal with reverse engineering of high-rise building settlements. This is modeled via the finite element method performed in the Plaxis 3D program. In the first part of this thesis, a calibration of input parameters of an appropriate material model – Hardening soil – is conducted. This calibration is a result of oedometric test data which were obtained within a geotechnical survey. An influence of soils over consolidation affecting calibration and the material model choice is described. Final values of reference stiffness parameters are used in a mathematical model of the focused area. This model is created for one half of the high-rise building plan, including vestibule. The high-rise building is founded in a foundation pit. The foundations of this building consist of raft foundation and piles of jet grouting. In the model, there are also changes in pore pressure during an excavation of foundation pit included. The functional model is used for parametric analyses, namely examining cases of object´s foundations and the possible influence of foundation pit´s symmetry on the object´s settlement. All the calculated processes in the object´s settlements are then compared to data obtained from geotechnical monitoring of the structure.
385

Návrh vysokootáčkového asynchronního motoru / Design of high speed induction motor

Čech, Jiří January 2020 (has links)
The first part of this paper presents general information about electromagnetic designing of an induction motor. Focus is on explanation of individual designing aspects and their effects on final motor parametres. Design principles for magnetic cores, slot dimensioning, stator winding and rotor squirrel cage are presented. Second chapter presents complete analytical computation of a given induction motor. Firstly several parametres need to be selected. Then sizing of stator and rotor is conducted. Secondly steady state equivalent parametres and related operating characteristics are computed. Following chapter consinsts of three final designs. In the last chapter results of mechanical analysis are presented.
386

Výpočet ustáleného chodu sítě 110 kV / Load Flow Solution of a 110kV Network

Tauš, Vladimír January 2008 (has links)
Content of this thesis is theoretic introduction to the steady state of network, theoretic analysis of methods, which serves for calculation of steady state of network such as Gauss Seidel iterative method or Newton Raphson modified method and economy in the energetics, concretely fixation of costs of the power line and calculation of the optimal time of building up the recuperative power line. This thesis includes calculation of steady state of requested network with normal trouble-free network and for criterion (n-1), their analysis and design of recuperative precaution.
387

Ustálený chod a zkratové poměry v síti 110 kV E.ON při můstkovém provozu transformátorů T402 a T403 v transformovně 400/110 kV Sokolnice / Steady state and short-circuit conditions within E.ON 110kV power network at bridge operation of transformers T402 and T403 in 400/100kV transformer station Sokolnice

Bernát, Jan January 2014 (has links)
The master’s thesis deals with a calculation of steady state and short-circuit conditions in a 110 kV system during a bridge operation of transformers in a Sokolnice substation. The theoretical part of the thesis deals with a calculation of steady state of a system using Newton’s iterative method, it investigates short-circuits – their timing, distinctive values and a method of their calculation. In the practical part the 100 kV grid supplied from Sokolnice substation is described. The main goal of the thesis is a comparation of two basic wirings: bridge operation of T202 and T203 transformers (contemporarily in service) and bridge operation of T402 and T403 (in service after 2017). These two wirings were controlled even during one state of emergency during which the Sokolnice substation will be affected by an outage of one busbar. Voltage conditions, loading of power line and transformers and overall power balance were controlled. Short-circuit conditions were also calculated and short-circuit resistance of particular substations was inspected. In the conclusion technical measures needed to ensure smooth bridge operation of convertors T402 and T403.
388

Ustálený chod a zkratové poměry v síti 110 kV E.ON napájené z transformovny Čebín / Steady state and short-circuit conditions in 110kV E.ON network fed from Čebín transformer station

Krutiš, Petr January 2015 (has links)
Master’s thesis deals with computation of steady state and short-circuit conditions in 110 kV nodal area of Čebín. The first part of thesis is theoretical. There is described computation of steady state and short-circuit conditions. There is description of 110 kV nodal area of Čebín too. There are made computations in the practical part. Two types of operation of transformers T401 and T402 are evaluated. The transformers operate independent at first, then they are connected in parallel. Voltage conditions in substations, load of lines and transformers, power losses and short-circuit resistance of substations in 110 kV nodal area of Čebín are evaluated based on the computations. There are compared the both types of operation of transformers in the end of practical part.
389

Charakterizace koloidních částic pomocí deprotonace v excitovaném stavu za použití pokročilých fluorescenčních technik / Characterization of coloid particles by excited-state proton transfer with advanced fluorescence techniques

Kotouček, Jan January 2016 (has links)
The deprotonation characteristics of fluorescent probes -naphthol and 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) were studied in this diploma thesis, using steady-state and time-resolved fluorescence spectroscopy. Two cationic surfactants, Septonex and cetyltrimethylammonium bromide (CTAB), were studied. These surfactants were measured in the complex with hyaluronan (1.75 MDa, 1 MDa and 300 kDa). Steady-state fluorescence was used for determination of critical aggregation concentration of each surfactant and pKa*. Time-resolved fluorescence decays were used to calculate the average lifetimes and the deprotonation constants of naphthol and HPTS. The measurement with hyaluronan were compared with the polystyrenesulfonate (PSS) – surfactant system. The effect of hydration shell of hyaluronan on hyaluronan – surfactant complex formation results from the comparison of above mentioned systems. Large differences were found in the deprotonation characteristic between surfactants and even between individual molecular weights of hyaluronan. The measurement shows that the hydration shell is located near to the dissociated carboxyl groups of hyaluronan chain, where the interaction with the positively charged surfactants occurs. Furthermore, the aggregation number of Septonex was determined by quenching of pyrene using cetylpyridinium chloride (CPC) as a quencher. The aggregation number for 20 mM Septonex solution was determined as a value of 104 molecules. CPC was used for confirmation of the localization of -naphthol in the micelles of CTAB and polymer – CTAB, respectively.
390

Etude d’un convertisseur DC-DC pour les réseaux haute tension à courant continu (HVDC) : modélisation et contrôle du convertisseur DC-DC modulaire multiniveaux (M2DC) / A DC-DC power converter study for High Voltage Direct Current (HVDC) grid : Model and control of the DC-DC Modular Multilevel Converter (M2DC)

Li, Yafang 11 July 2019 (has links)
Les travaux présentés dans ce mémoire portent sur les convertisseurs continu-continu (DC/DC) pour les réseaux de transport à Courant Continu (HVDC) dans un contexte de réseau maillé de type Multi Terminaux DC (MTDC). Dans ce genre de réseau, les convertisseurs DC/DC sont nécessaires pour interconnecter ces réseaux. L’objectif de ce travail est donc d’étudier un convertisseur DC/DC pour des applications à haute tension et forte puissance. De nombreux convertisseurs DC/DC classiques existent, mais ne sont pas adaptés à ces niveaux de tension et puissance. Le volume et coût sont les points clés de l’étude pour l’industrialisation des structures dédiées aux réseaux HVDC. Parmi les structures identifiées, le convertisseur DC-DC Modulaire Multiniveaux (M2DC), récent et compact, a été finalement choisi. Le travail proposé développe l’étude du M2DC en régime établi et une modélisation en modèle moyen de ce convertisseur. Ensuite, des lois de contrôle sont proposées pour valider les analyses précédentes sur la base du principe de l’inversion du modèle. Le travail vise enfin à valider les analyses et le contrôle à l’aide de la maquette du Convertisseur Modulaire Multiniveaux (MMC) du L2EP. Pour cela, un dimensionnement du M2DC basé sur le MMC existant est proposé. Enfin, des simulations HIL (Hardware-In-the-Loop) valident les analyses et montrent la faisabilité du prototypage du M2DC / This work is based on Multi Terminal Direct Current (MTDC) grids. In the MTDC grid, DC/DC converter stations are needed to connect different HVDC grids. A lot of DC/DC converters have been studied and developed, but are not suitable for high voltage and great power constraints. Therefore, the objective of this work is the study of a DC/DC converter for high voltage and great power applications. For the potentially HVDC applications, the volume and costs are major criteria. According to this, a high voltage and great power potential DC/DC converter is selected, which is the DC-DC Modular Multilevel Converter (M2DC). Focusing on the M2DC, the work proposes analyses in steady state and builds an average model for the converter. Based on the average model, the basic control algorithm for the converter is developed to validate the previous analysis. Since the thesis aims to use the existing L2EP Modular Multilevel Converter (MMC) to test the M2DC model and control, a design of the M2DC based on MMC is proposed. Finally, the M2DC HIL (Hardware In-the-Loop) simulations results are presented confirming previous analyses and allowing to go on to prototyping the M2DC on the base of the existing MMC

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