The protection of small village Světnov against rural zone water

Cílem této diplomové práce je navrhnout vhodné protipovodňové opatření v obci Světnov, vypočítat kritickou povodeň ze Směrnice pro velmi malá povodí a tato data vložíme do programu HEC-RAS 4.1.0, kde budou dále upravována, aby se našlo co nejvhodnější a nejefektivnější řešení. Jako protipovodňová opatření budou navrhnuty dva suché poldry východně od obce. Hráze musejí být navrhnuty tak, aby byli schopné pojmout 100–letou povodeň, která bude vypočítána podle Směrnice pro velmi malá povodí. Z materiálů obce víme, že povodeň musíme převést do stávajícího potrubí, které je schopno pojmout 1 m3/s. Součástí práce bude projekční řešení hrází, odpadních koryt a funkčních objektů v programu AutoCAD 2008.The aim of this thesis is to propose appropriate flood protection measures in the small village Světnov, calculate the critical flood of guideline for very small basin and insert the data into the program HEC-RAS 4.1.0, where they will be further treated in order to find the most appropriate and effective solutions. As flood control measures will be designed two dry polders east of the village. Dikes should be designed so to be able to accommodate 100-year flood, which will be calculated according of guideline for very small basin. Of the materials community, we know that we need to convert flood into the existing pipeline, which is able to accommodate 1 m3/s. The thesis will design solutions dams, sewage channels and function objects in the program AutoCAD 2008.

Methodology for Optimization of 110 kV Lines Renovation

Import 22/07/2015Cílem práce bylo stanovit pořadí obnovy jednotlivých údržbových úseků vedení 110 kV v distribuční oblasti Morava. Toho bylo dosaženo za pomoci metodiky, která pracuje na principech spolehlivostně orientované údržby a bere v potaz jak technický stav zařízení, tak jeho důležitost a umožňuje efektivněji směrovat tok finančních prostředků na opravy zařízení. Práce ve svém závěru obsahuje tabulky technického stavu, důležitosti vedení a priority obnovy pro každý údržbový úsek v distribuční oblasti.This thesis purpose was to establish renovation order for individual maintenance sections of 110 kV lines in the distribution area of Moravia. This was achieved through a metodology that works on the princiles of reliability centered maintenance which takes into consideration both the technical condition of equipement and its importance. This approach allows more efficiently direct flow of funds for repairs. Thesis in its conclusion contains tables of technical condition, the importance of lines and renewal priority for each maintenance section in the distribution area.410 - Katedra elektroenergetikyvelmi dobř

Inversion of the exciton built-in dipole moment in In(Ga)As quantum dots via nonlinear piezoelectric effect

We show that anisotropic biaxial stress can be used to tune the built-in dipole moment of excitons confined in In(Ga)As quantum dots up to complete erasure of its magnitude and inversion of its sign. We demonstrate that this phenomenon is due to piezoelectricity. We present a model to calculate the applied stress, taking advantage of the so-called piezotronic effect, which produces significant changes in the current-voltage characteristics of the strained diode-membranes containing the quantum dots. Finally, self-consistent k.p calculations reveal that the experimental findings can be only accounted for by the nonlinear piezoelectric effect, whose importance in quantum dot physics has been theoretically recognized although it has proven difficult to single out experimentally.Comment: 6 pages, 4 figure

Interband absorption edge in the topological insulators Bi-2(Te1-xSex)(3)

We have investigated the optical properties of thin films of topological insulators Bi2Te3, Bi2Se3, and their alloys Bi-2(Te1-x Se-x)(3) on BaF2 substrates by a combination of infrared ellipsometry and reflectivity in the energy range from 0.06 to 6.5 eV. For the onset of interband absorption in Bi2Se3, after the correction for the Burstein-Moss effect, we find the value of the direct band gap of 215 +/- 10 meV at 10 K. Our data support the picture that Bi2Se3 has a direct band gap located at the Gamma point in the Brillouin zone and that the valence band reaches up to the Dirac point and has the shape of a downward-oriented paraboloid, i.e., without a camel-back structure. In Bi2Te3, the onset of strong direct interband absorption at 10 K is at a similar energy of about 200 meV, with a weaker additional feature at about 170 meV. Our data support the recent GW band-structure calculations suggesting that the direct interband transition does not occur at the Gamma point but near the Z-F line of the Brillouin zone. In the Bi-2(Te1-x Se-x)(3) alloy, the energy of the onset of direct interband transitions exhibits a maximum near x = 0.3 (i.e., the composition of Bi2Te2Se), suggesting that the crossover of the direct interband transitions between the two points in the Brillouin zone occurs close to this composition

Interpretation of the in-plane infrared response of the high-Tc cuprate superconductors involving spin fluctuations revisited

The in-plane infrared response of the high-Tc cuprate superconductors was studied using the spin-fermion model, where charged quasiparticles of the copper-oxygen planes are coupled to spin fluctuations. First, we analyzed structures of the superconducting-state conductivity reflecting the coupling of the quasiparticles to the resonance mode observed by neutron scattering. The conductivity computed with the input spin susceptibility in the simple form of the mode exhibits two prominent features: an onset of the real part of the conductivity starting around the frequency of the mode omega_{0} and a maximum of a related function W(omega), roughly proportional to the second derivative of the scattering rate, centered approximately at omega=omega_{0}+Delta_{0}/hbar, where Delta_{0} is the maximum value of the superconducting gap. The two structures are well known from earlier studies. Their physical meaning, however, has not been sufficiently elucidated thus far. Our analysis involving quasiparticle spectral functions provides a clear interpretation. Second, we explored the role played by the spin-fluctuation continuum. Third, we investigated the temperature dependence of the conductivity, of the intraband spectral weight, and of the effective kinetic energy. The changes of the latter two quantities below Tc are determined by the formation of the gap, by a feedback effect of the spin fluctuations on the quasiparticles, and by a significant shift of the chemical potential.Comment: 20 pages, 18 figures, submitted to Physical Review

Understanding hydrogen recombination line observations with ALMA and EVLA

Hydrogen recombination lines are one of the major diagnostics of H II region physical properties and kinematics. In the near future, the Expanded Very Large Array (EVLA) and the Atacama Large Millimeter Array (ALMA) will allow observers to study recombination lines in the radio and sub-mm regime in unprecedented detail. In this paper, we study the properties of recombination lines, in particular at ALMA wavelengths. We find that such lines will lie in almost every wideband ALMA setup and that the line emission will be equally detectable in all bands. Furthermore, we present our implementation of hydrogen recombination lines in the adaptive-mesh radiative transfer code RADMC-3D. We particularly emphasize the importance of non-LTE (local thermodynamical equilibrium) modeling since non-LTE effects can drastically affect the line shapes and produce asymmetric line profiles from radially symmetric H II regions. We demonstrate how these non-LTE effects can be used as a probe of systematic motions (infall & outflow) in the gas. We use RADMC-3D to produce synthetic observations of model H II regions and study the necessary conditions for observing such asymmetric line profiles with ALMA and EVLA.Comment: MNRAS in pres

Voigt Profile Fitting to Quasar Absorption Lines: An Analytic Approximation to the Voigt-Hjerting Function

The Voigt-Hjerting function is fundamental in order to correctly model the profiles of absorption lines imprinted in the spectra of bright background sources by intervening absorbing systems. In this work we present a simple analytic approximation to this function in the context of absorption line profiles of intergalactic HI absorbers. Using basic calculus tools, we derive an analytic expression for the Voigt-Hjerting function that contains only fourth order polynomial and Gaussian functions. In connection with the absorption coefficient of intergalactic neutral hydrogen, this approximation is suitable for modeling Voigt profiles with an accuracy of $10^{-4}$ or better for an arbitrary wavelength baseline, for column densities up to $N_{HI} = 10^{22} cm^{-2}$, and for damping parameters $a \lesssim 10^{-4}$, i.e. the entire range of parameters characteristic to all Lyman transitions arising in a variety of HI absorbing systems such as Lyman Alpha Forest clouds, Lyman Limit systems and Damped Lyman Alpha systems. We hence present an approximation to the Voigt-Hjerting function that is both accurate and flexible to implement in various types of programming languages and machines, and with which Voigt profiles can be calculated in a reliable and very simple manner.Comment: 11 pages, 8 figures, accepted for publication in MNRAS after referee's revision and corresponding change

Correlation between the Josephson coupling energy and the condensation energy in bilayer cuprate superconductors

We review some previous studies concerning the intra-bilayer Josephson plasmons and present new ellipsometric data of the c-axis infrared response of almost optimally doped Bi_{2}Sr_{2}CaCu_{2}O_{8}. The c-axis conductivity of this compound exhibits the same kind of anomalies as that of underdoped YBa_{2}Cu_{3}O_{7-delta}. We analyze these anomalies in detail and show that they can be explained within a model involving the intra-bilayer Josephson effect and variations of the electric field inside the unit cell. The Josephson coupling energies of different bilayer compounds obtained from the optical data are compared with the condensation energies and it is shown that there is a reasonable agreement between the values of the two quantities. We argue that the Josephson coupling energy, as determined by the frequency of the intra-bilayer Josephson plasmon, represents a reasonable estimate of the change of the effective c-axis kinetic energy upon entering the superconducting state. It is further explained that this is not the case for the estimate based on the use of the simplest ``tight-binding'' sum rule. We discuss possible interpretations of the remarkable agreement between the Josephson coupling energies and the condensation energies. The most plausible interpretation is that the interlayer tunneling of the Cooper pairs provides the dominant contribution to the condensation energy of the bilayer compounds; in other words that the condensation energy of these compounds can be accounted for by the interlayer tunneling theory. We suggest an extension of this theory, which may also explain the high values of T_{c} in the single layer compounds Tl_{2}Ba_{2}CuO_{6} and HgBa_{2}CuO_{4}, and we make several experimentally verifiable predictions.Comment: 16 pages (including Tables) and 7 figures; accepted for publication in Physical Review