SELV power sources

Cílem této diplomové práce bylo prostudovat požadované vlastnosti napájecích zdrojů SELV využívaných pro elektrická zařízení třídy III. V první části diplomové práce jsou shrnuty obecné poznatky o zdrojích. Především jsou zde rozebrány spínané zdroje SELV, jejich nadproudové, přepěťové a tepelné ochrany a možnosti řešení zdrojů SELV z hlediska požadované izolační bezpečnosti. Druhá část se zabývá konkrétním návrhem napájecího zdroje SELV 230VAC/24VDC s výstupním výkonem do 70W, jeho realizací a měřením jeho parametrů.The aim of this diploma paper is to examine the required characteristics of power sources SELV which are used for electric devices of category III. The first part of this diploma paper deals with general knowledge considering power sources. With the focus on switching power sources SELV, their overcurrent, thermal-overload and overvoltage protection and possible solutions of power sources SELV from the aspect of the required isolating safety. The second part of this work deals with the specific design of the power source SELV 230VAC/24VDC with the power output to 70W, with its implementation and with the measuring of its parameters.

Synthesis of Modern Structures of Frequency Filters

Perspektivní oblastí, kam se zaměřuje současná pozornost v oboru syntézy moderních kmitočtových struktur, je oblast kmitočtů filtrů do 10 MHz, neboť rychlý rozvoj moderních technologií umožňuje realizaci moderních struktur analogových kmitočtových filtrů i v této požadované oblasti. V souvislosti s tím je však třeba propracovat metody syntézy a optimalizace těchto struktur s ohledem na možnosti současných moderních aktivních prvků (operační zesilovače s napěťovou zpětnou vazbou s tranzitním kmitočtem řádově jednotky GHz, operační zesilovače s proudovou zpětnou vazbou, konvejory, transimpedanční operační zesilovače). V této práci byly podrobně analyzovány aktivní bloky syntetických induktorů (SI) a frekvenčně závislých negativních rezistorů (FDNR) a byly odvozeny vztahy pro jejich základní parametry. Pozornost byla zaměřena na optimalizaci základních stavebních bloků 2. řádu a jejich vlastností s moderními aktivními prvky. Byly analyzovány a optimalizovány z hlediska jejich využití v obvodech vyšších řádů. Byla provedena řada návrhů filtrů a ověřena metodika syntézy a optimalizace příčkových filtrů vyšších řádů s moderními aktivními bloky. Pozornost byla zaměřena na metody optimalizace syntézy filtrů se ztrátovými aktivními bloky realizovanými na základě RLC prototypů. V oblasti aktivních filtrů vyšších řádů byly provedeny citlivostní simulace udávající představu o citlivosti kaskádních a nekaskádních struktur ARC filtrů. Pro ověření teoretických závěrů byla realizována celá řada vzorků optimalizovaných filtrů a jejich parametry byly ověřeny měřením. V závěru práce jsou uvedeny realizace filtrů pro konkrétní požadované praktické aplikace.Within modern frequency structures, the filter frequency region of up to 10 MHz constitutes a promising research topic that currently attracts intensive attention of specialists interested in the problem. The main reason of this fact consists in that the rapid development of modern technology allows the production of innovated structures of the analog frequency filters required in the defined band. In this context, however, it is also necessary to refine the methods applied in the synthesis and optimization of these structures; such improvement should be carried out with respect to fundamental properties and usability of today's active elements (operational amplifiers with voltage feedback whose Gain Bandwidth Product ranges within units of GHz, operational amplifiers with current feedback, conveyors, transimpedance operational amplifiers). In this thesis, active blocks of synthesis inductors (SIs) and frequency dependent negative resistors (FDNRs) are examined in detail, and the author provides novel formulas to define the basic parameters of the dual circuits. Due emphasis was placed on optimizing the basic building blocks of the second order and defining the variation of their properties caused by the addition of modern active elements. The blocks were analyzed and modified in view of their possible use in higher-order circuits. For active filters of a higher order, simulations were performed to indicate the actual sensitivity of the cascade and non-cascade ARC structures. The following phase of the research comprised mainly the designing of several filters, and this activity was further completed with the verification of the methodology for the synthesis and optimization of higher-order loss ladder filters with modern active blocks. Special attention was paid also to the methods enabling the optimization of such filters, which are invariably based on RLC prototypes. In order to verify the theoretical conclusions, the author materialized a large number of sample optimized filters and measured their parameters. The closing section of the thesis describes the use of the filters in specific applications.

Role of the E2g phonon in the superconductivity of MgB2: a Raman scattering study

Temperature dependent Raman scattering studies in polycrystalline MgB2(10<T<300 K)reveal that the E2g phonon does not experience any self energy renormalization effect across the superconducting critical temperature Tc ~ 40 K. In contrast, most of the current theoretical models rely on the role of the E2g phonon in the electron-phonon coupling mechanism of superconductivity in MgB2. According to these models, a hardening of 12% is expected below Tc at the Gamma point of the Brillouim zone. In the presence of our results, those models must be reviewed. The analysis of the temperature dependence of the E2g phonon frequency yields to a isobaric Gruneisen parameter of -1.2< gama(E2g)< 0.2, smaller than the value of 3.9 obtained from isothermal Raman experiments under pressure. It is suggested that this apparent disagreement can be explained in terms of pressure induced changes of the topology of the Fermi surface. Finally we notice that the phonon linewidth presents the expected two-phonon anharmonic decay as a function of T and no anomalous temperature dependence of the linewidth is observed near Tc.Comment: Published in Solid State Comm. 125, 499 (2003

Consistent economic cross-sectoral climate change impact scenario analysis: Method and application to Austria

AbstractClimate change triggers manifold impacts at the national to local level, which in turn have various economy-wide implications (e.g. on welfare, employment, or tax revenues). In its response, society needs to prioritize which of these impacts to address and what share of resources to spend on each respective adaptation. A prerequisite to achieving that end is an economic impact analysis that is consistent across sectors and acknowledges intersectoral and economy-wide feedback effects. Traditional Integrated Assessment Models (IAMs) are usually operating at a level too aggregated for this end, while bottom-up impact models most often are not fully comprehensive, focusing on only a subset of climate sensitive sectors and/or a subset of climate change impact chains. Thus, we develop here an approach which applies climate and socioeconomic scenario analysis, harmonized economic costing, and sector explicit bandwidth analysis in a coupled framework of eleven (bio)physical impact assessment models and a uniform multi-sectoral computable general equilibrium model. In applying this approach to the alpine country of Austria, we find that macroeconomic feedbacks can magnify sectoral climate damages up to fourfold, or that by mid-century costs of climate change clearly outweigh benefits, with net costs rising two- to fourfold above current damage cost levels. The resulting specific impact information – differentiated by climate and economic drivers – can support sector-specific adaptation as well as adaptive capacity building

Predicted occurrence of ancient coppice woodlands in the Czech Republic

Coppicing started in the Neolithic period and has been practiced throughout European history. This traditional silvicultural system was abandoned in many European countries during the 20th century. The Czech Republic now has a very low proportion of coppice woods (CW), as more than 1000 km2 CW were converted into high forests after World War II. Nevertheless, many CW were maintained as stored coppices, which could be the last remainders of ancient coppice woods (ACW) in the Czech Republic. Knowledge of area and distribution of stored coppices is currently missing in the Czech Republic, because they are recorded as high forests in forest management plans. Many stored forests are currently approaching the maturity age, with a high risk that these last ACW remainders will be lost; therefore, an inventory of ancient coppice woods is necessary. In our study, we develop an index of likelihood of coppice occurrence (COP) based on the distribution of habitats favourable for coppices, as well as on past and current occurrence of CW in the Czech Republic from historical maps. COP index values were then used to generate a map showing the relative likelihoods of occurrence of ACW, which can serve as a baseline to support the compilation of an ACW inventory and their mapping in the field. Our results can help prioritize forest areas to be inventoried based on their higher probabilities of ACW occurrence.O

Orographically induced spontaneous imbalance within the jet causing a large-scale gravity wave event

To better understand the impact of gravity waves (GWs) on the middle atmosphere in the current and future climate, it is essential to understand their excitation mechanisms and to quantify their basic properties. Here a new process for GW excitation by orography–jet interaction is discussed. In a case study, we identify the source of a GW observed over Greenland on 10 March 2016 during the POLSTRACC (POLar STRAtosphere in a Changing Climate) aircraft campaign. Measurements were taken with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) instrument deployed on the High Altitude Long Range (HALO) German research aircraft. The measured infrared limb radiances are converted into a 3D observational temperature field through the use of inverse modelling and limited-angle tomography. We observe GWs along a transect through Greenland where the GW packet covers ≈ 1/3 of the Greenland mainland. GLORIA observations indicate GWs between 10 and 13 km of altitude with a horizontal wavelength of 330 km, a vertical wavelength of 2 km and a large temperature amplitude of 4.5 K. Slanted phase fronts indicate intrinsic propagation against the wind, while the ground-based propagation is with the wind. The GWs are arrested below a critical layer above the tropospheric jet. Compared to its intrinsic horizontal group velocity (25–72 m s$^{-1}$) the GW packet has a slow vertical group velocity of 0.05–0.2 m s$^{-1}$. This causes the GW packet to propagate long distances while spreading over a large area and remaining constrained to a narrow vertical layer. A plausible source is not only orography, but also out-of-balance winds in a jet exit region and wind shear. To identify the GW source, 3D GLORIA observations are combined with a gravity wave ray tracer, ERA5 reanalysis and high-resolution numerical experiments. In a numerical experiment with a smoothed orography, GW activity is quite weak, indicating that the GWs in the realistic orography experiment are due to orography. However, analysis shows that these GWs are not mountain waves. A favourable area for spontaneous GW emission is identified in the jet by the cross-stream ageostrophic wind, which indicates when the flow is out of geostrophic balance. Backwards ray-tracing experiments trace into the jet and regions where the Coriolis and the pressure gradient forces are out of balance. The difference between the full and a smooth-orography experiment is investigated to reveal the missing connection between orography and the out-of-balance jet. We find that this is flow over a broad area of elevated terrain which causes compression of air above Greenland. The orography modifies the wind flow over large horizontal and vertical scales, resulting in out-of-balance geostrophic components. The out-of-balance jet then excites GWs in order to bring the flow back into balance. This is the first observational evidence of GW generation by such an orography–jet mechanism

Increase in Low-Frequency Oscillations in fNIRS as Cerebral Response to Auditory Stimulation with Familiar Music

Recognition of typical patterns of brain response to external stimuli using near-infrared spectroscopy (fNIRS) may become a gateway to detecting covert consciousness in clinically unresponsive patients. This is the first fNIRS study on the cortical hemodynamic response to favorite music using a frequency domain approach. The aim of this study was to identify a possible marker of cognitive response in healthy subjects by investigating variations in the oscillatory signal of fNIRS in the spectral regions of low-frequency (LFO) and very-low-frequency oscillations (VLFO). The experiment consisted of two periods of exposure to preferred music, preceded and followed by a resting phase. Spectral power in the LFO region increased in all the subjects after the first exposure to music and decreased again in the subsequent resting phase. After the second music exposure, the increase in LFO spectral power was less distinct. Changes in LFO spectral power were more after first music exposure and the repetition-related habituation effect strongly suggest a cerebral origin of the fNIRS signal. Recognition of typical patterns of brain response to specific environmental stimulation is a required step for the concrete validation of a fNIRS-based diagnostic tool

Biomass burning pollution in the South Atlantic upper troposphere: GLORIA trace gas observations and evaluation of the CAMS model

In this study, we present simultaneous airborne measurements of peroxyacetyl nitrate (PAN), ethane (C2H6), formic acid (HCOOH), methanol (CH3OH), and ethylene (C2H4) above the South Atlantic in September and October 2019. Observations were obtained from the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA), as two-dimensional altitude cross sections along the flight path. The flights were part of the SouthTRAC (Transport and Composition in the Southern Hemisphere Upper Troposphere/Lower Stratosphere) campaign with the German High Altitude and Long Range Research Aircraft (HALO). On two flights (8 September 2019 and 7 October 2019), large enhancements of all these substances were found between 7 and 14 km altitude with maximum volume mixing ratios (VMRs) of 1000 pptv for PAN, 1400 pptv for C2H6, 800 pptv for HCOOH, 4500 pptv for CH3OH, and 200 pptv for C2H4. One flight showed a common filamentary structure in the trace gas distributions, while the second flight is characterized by one large plume. Using backward trajectories, we show that measured pollutants likely reached upper troposphere and lower stratosphere (UTLS) altitudes above South America and central Africa, where elevated PAN VMRs are visible at the surface layer of the Copernicus Atmosphere Monitoring Service (CAMS) model during the weeks before both measurements. In comparison to results of the CAMS reanalysis interpolated onto the GLORIA measurement geolocations, we show that the model is able to reproduce the overall structure of the measured pollution trace gas distributions. For PAN, the absolute VMRs are in agreement with the GLORIA measurements. However, C2H6 and HCOOH are generally underestimated by the model, while CH3OH and C2H4, the species with the shortest atmospheric lifetimes of the pollution trace gases discussed, are overestimated by CAMS. The good agreement between model and observations for PAN suggests that the general transport pathways and emissions locations are well captured by the model. The poorer agreement for other species is therefore most likely linked to model deficiencies in the representation of loss processes and emission strength

Design of the HEM-POWR study:A prospective, observational study of real-world treatment with damoctocog alfa pegol in patients with haemophilia A

INTRODUCTION: Haemophilia A is a rare bleeding disorder caused by defects in coagulation factor VIII (FVIII). Damoctocog alfa pegol (BAY 94–9027, Jivi, Bayer, Germany) is a site-specifically PEGylated, extended-half-life, recombinant FVIII, approved for use in previously treated patients (PTPs) aged ≥12 years with haemophilia A. However, a real-world evidence regarding routine clinical use of damoctocog alfa pegol is limited. METHODS AND ANALYSIS: HEM-POWR is a multinational, multicentre, non-interventional, prospective, postmarketing cohort study evaluating the effectiveness and safety of real-world treatment with damoctocog alfa pegol. Estimated enrolment is ≥200 PTPs with haemophilia A, receiving damoctocog alfa pegol (on-demand, prophylaxis or intermittent prophylaxis (as per local label)), observed for 36 months. Primary outcomes are total bleeding events and annualised bleeding rate; secondary outcomes include long-term safety, joint health, pharmacokinetics, patient-reported outcomes (PROs) from validated questionnaires and perioperative haemostasis. Where applicable, reasons for switching to damoctocog alfa pegol, choice of treatment regimen and dose will also be captured. Exploratory and descriptive statistical analyses will be performed, and will be stratified by parameters including, but not limited to, prophylaxis regimen and haemophilia severity. Patients can record bleeds and consumption in electronic (e) Diaries, ePROs, and can access non-promotional study information (videos explaining study procedures) via an online patient portal. Optionally, patients can enrol in the LIFE-ACTIVE substudy designed to investigate the relationship between activity (measured by the ActiGraph CP Insight watch) and effectiveness parameters collected from HEM-POWR. ETHICS AND DISSEMINATION: Study approval was obtained by local independent ethics committees and authorities in participating study centres across Europe, the Americas and Asia. Informed consent from patients or their legal representative is a requirement for participation. The study results will be submitted for publication in a peer-reviewed scientific journal and presented at scientific conferences. TRIAL REGISTRATION NUMBERS: NCT03932201, EUPAS26416. PROTOCOL VERSION AND DATE: V.1.2, 27 September 2019

Starobylé výmladkové lesy v krajině České republiky

Ancient coppice woodlands are forest stands of coppice origin with a long-term continual development and preserved typical natural and historic elements of old coppices. Significant natural elements in ancient coppices include polycormons of coppice shoots, pollard trees, trees with holes, dendrotelms, reserved trees, ecotones, glades and significant plant and animal species. Significant historic elements of localities with ancient coppices include archaeological monuments, boundary ditches and walls, boundary stones, boundary trees, myths and legends, sacral objects, old roads and paths, technical objects and plough land remainders. The paper presents differentiation of assumptions for the occurrence of ancient coppices in the territory of the Czech Republic using the COPF coefficient and examples of results from basic regional inventory (Kuřim region) and detailed local survey (locality Lebeďák) of coppice-originated forests. The extinction of the phenomenon of ancient coppice woodlands would mean irreparable impoverishment of the natural and cultural heritage.Za starobylé výmladkové lesy označujeme lesní porosty výmladkového původu s dlouhodobým kontinuálním vývojem a zachovanými typickými přírodními a historickými prvky starých pařezin. K významným přírodním prvkům ve starobylých pařezinách patří výmladkové polykormony, hlavaté stromy, doupné stromy, dendrotelmy, výstavky, ekotony, světliny a významné druhy rostlin a živočichů. Mezi významné historické prvky lokalit starobylých výmladkových lesů řadíme archeologické památky, hraniční příkopy a valy, hraniční kameny, hraniční stromy, pověsti a legendy, sakrální objekty, staré cesty a stezky, technické objekty a zbytky plužiny. V článku je prezentována diferenciace předpokladů výskytu starobylých pařezin na území České republiky s využitím koeficientu COPF a příklady výsledků základního regionálního (Kuřimsko) a podrobného lokálního (Lebeďák) průzkumu lokalit lesů výmladkového původu. Zánik fenoménu starobylých pařezin by znamenal nenapravitelné ochuzení přírodního a kulturního dědictví.O