Current trends in development of aircraft powerplant

Tato bakalářská práce popisuje současné trendy a novinky ve vývoji leteckých pohonných jednotek, jejich aplikaci v současnosti vyráběných leteckých pohonných jednotkách. Jednotlivá konstrukční řešení vyplývajících z diskutovaných trendů jsou v práci demonstrována a popsána na ukázkách zkonstruovaných a vyvíjených leteckých motorech.This bachelors thesis describes current trends and news in development in aircraft powerplants and their applications at currently produced aircraft engines. Individual construction solutions resulting from discussed trends are shown and described on examples of designed and developed aircraft engines.

Additional Options of the ECCAIRS capabilities at national level

Diplomová práce je zaměřena na vytvoření návrhu modifikace podávání povinných i dobrovolných hlášení o události na národní úrovni. V první části práce je popsán databázový systém ECCAIRS a také legislativa, která se týká podávání hlášení o událostech, konkrétně Nařízení Evropského parlamentu a Rady (EU) č.376/2014. Druhá část práce se zabývá popsáním navrhnutých řešení pro zlepšení podávání hlášení. Součástí druhé části je i vytvoření formuláře pro podávání hlášení.The focus of this diploma thesis is a development of a proposal for the modification of the reporting mandatory and voluntary occurrances on the national basis. In the first part of this thesis is describtion database system ECCAIRS and also describtion of the legislation which relates to the reporting of occurrances, specifically Regulation (EU) No 376/2014 of the European Parliament and of the Council. Second part of this diploma thesis is about the description of the proposed solutions to improve reporting system of occurrances. Second part also includes creation of the form for reporting occurrances.

Photochemical and photoelectrochemical quenching of chlorophyll fluorescence in photosystem II

This paper deals with kinetics and properties of variable fluorescence in leaves and thylakoids upon excitation with low intensity multi-turnover actinic light pulses corresponding with an excitation rate of about 10 Hz. These show a relatively small and amply documented rise in the sub-s time range towards the plateau level Fpl followed by a delayed and S-shaped rise towards a steady state level Fm which is between three and four fold the initial dark fluorescence level Fo. Properties of this retarded slow rise are i) rate of dark recovery is (1–6 s)- 1, ii) suppression by low concentration of protonophores, iii) responsiveness to complementary single turnover flash excitation with transient amplitude towards a level Fm which is between five and six fold the initial dark fluorescence level Fo and iv) in harmony with and quantitatively interpretable in terms of a release of photoelectrochemical quenching controlled by the trans-thylakoid proton pump powered by the light-driven Q cycle. Data show evidence for a sizeable fluorescence increase upon release of (photo) electrochemical quenching, defined as qPE. Release of qPE occurs independent of photochemical quenching defined here as qPP even under conditions at which qPP = 1. The term photochemical quenching, hitherto symbolized by qP, will require a new definition, because it incorporates in its present form a sizeable photoelectrochemical component. The same is likely to be true for definition and use of qN as an indicator of non photochemical quenchin

The analysis of PS II photochemical activity using single and multi- turnover excitations

Paper describes chlorophyll a fluorescence measurements in algal cells, and intact plant leaves and isolated chloroplasts. It focuses on amplitude and 10 µs-resolved kinetics of variable fluorescence responses upon excitation with fluorescence-saturating pulses (SP) and with 25 µs saturating single turnover flashes (STF) which are exposed before, during and after a 100 s actinic illumination (AL) of low and high intensity. In addition to the amply documented suppression of the maximal variable fluorescence from Fm to F’m, the relative proportion of the distinguished O-J- , J-I and I-P-phases of an SP-induced response is shown to be distinctly different in dark- and light-adapted leaves. The O-J-phase in the 0.01 to 1 ms time range is much less sensitive to light adaptation than the other phases in the 1 – 200 ms range. In algae and chloroplasts, the amplitude FmSTF of the STF-induced response is hardly affected by a shift from the dark- to the light-activated steady state. The results support the hypothesis that the maximal variable fluorescence Fm induced by a multiple-turnover, fluorescence-saturating pulse (SP), is associated with the release of photochemical and photoelectrochemical quenching. It is argued that the OJIPMT- or Kautsky induction curve of variable chlorophyll fluorescence in the 0 – 100 s time range is the reflection of the release of photochemical quenching supplemented with a temporary Photosystem I (PSI)-dependent photoelectric stimulation and transient release of photoelectrochemical quenching of radiative energy loss in the Photosystem II (PSII) antennas, rather than solely of a decrease in PSII photochemical activity as is usually concluded

On the chlorophill a fluorescence yield in chloroplasts upon excitation with twin turnover flashes (TTF) and high frequency flash trains

Chlorophyll fluorescence is routinely taken as a quantifiable measure of the redox state of the primary quinone acceptor QA of PSII. The variable fluorescence in thylakoids increases in a single turnover flash (STF) from its low dark level F o towards a maximum F mSTF when QA becomes reduced. We found, using twin single turnover flashes (TTFs) that the fluorescence increase induced by the first twin-partner is followed by a 20¿30% increase when the second partner is applied within 20¿100 ¿s after the first one. The amplitude of the twin response shows a period-of-four oscillation associated with the 4-step oxidation of water in the Kok cycle (S states) and originates from two different trapped states with a life time of 0.2¿0.4 and 2¿5 ms, respectively. The oscillation is supplemented with a binary oscillation associated with the two-electron gate mechanism at the PSII acceptor side. The F(t) response in high frequency flash trains (1¿4 kHz) shows (i) in the first 3¿4 flashes a transient overshoot 20¿30% above the F mSTF = 3*F o level reached in the 1st flash with a partial decline towards a dip D in the next 2¿3 ms, independent of the flash frequency, and (ii) a frequency independent rise to F m = 5*F o in the 3¿60 ms time range. The initial overshoot is interpreted to be due to electron trapping in the S0 fraction with QB-nonreducing centers and the dip to the subsequent recovery accompanying the reoxidation of the double reduced acceptor pair in these RCs after trapping. The rise after the overshoot is, in agreement with earlier findings, interpreted to indicate a photo-electrochemical control of the chlorophyll fluorescence yield of PSII. It is anticipated that the double exciton and electron trapping property of PSII is advantageous for the plant. It serves to alleviate the depression of electron transport in single reduced QB-nonreducing RCs, associated with electrochemically coupled proton transport, by an increased electron trapping efficiency in these centers

The chlorophyll a fluorescence induction pattern in chloroplasts upon repetitive single turnover excitations: Accumulation and function of QB-nonreducing centers

The increase of chlorophyll fluorescence yield in chloroplasts in a 12.5 Hz train of saturating single turnover flashes and the kinetics of fluorescence yield decay after the last flash have been analyzed. The approximate twofold increase in Fm relative to Fo, reached after 30-40 flashes, is associated with a proportional change in the slow (1-20 s) component of the multiphasic decay. This component reflects the accumulation of a sizeable fraction of QB-nonreducing centers. It is hypothesized that the generation of these centers occurs in association with proton transport across the thylakoid membrane. The data are quantitatively consistent with a model in which the fluorescence quenching of QB-nonreducing centers is reversibly released after second excitation and electron trapping on the acceptor side of Photosystem I