27 research outputs found

    Compact datalogger with flash memory

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    Práce se zabývá konstrukcí bateriového dataloggeru se záznamem na paměťovou flash kartu. V úvodu jsou diskutovány parametry, funkce a vybavení běžně dostupných dataloggerů. Dále je nastíněna problematika číslicového měření analogových veličin a ve zbytku práce se rozebírá vlastní konstrukce dataloggeru. Ta zahrnuje návrh zapojení, desky s plošnými spoji, programové vybavení mikrokontroléru, popis ovládání a programové vybavení pro PC.This thesis deals with design of small datalogger with flash memory card. At first are discussed parameters, functions and features of dataloggers. The second part deals with a problem of digital measurement of analog signals. The rest of this thesis gives attention to main goal which is design of datalogger. It consists of circuit diagram, layout of printed circuit board, firmware for microcomputer and software for PC.

    Remote maintenance of the microcontroller systems

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    Práce řeší problematiku vzdálené správy paměti programu (firmware) jednočipových systémů založených na mikrokontrolérech řady Atmel AVR prostřednictvím rozhraní Ethernet a protokolů TCP/IP. Komunikaci zprostředkovává embedded server NE-4100T. V úvodu jsou rozebrány vlastnosti použitého embedded serveru a způsoby programování mikrokontrolérů Atmel AVR. Zvoleným řešením úlohy je pak metoda bootloaderu, pro niž byl navržen komunikační protokol, softwarové vybavení mikrokontroléru a obslužný program pro PC. Po hardwarové stránce řešení zahrnuje návrh obvodů pro propojení serveru NE-4100T s modulem mikrokontroléru, snižujícího měniče napětí, obvodu hodin reálného času a příslušné desky plošných spojů. V projektu se podařilo splnit požadavky na vzdálenou správu paměti programu mikrokontroléru, ale nebylo nalezeno dostatečné řešení stran zabezpečení proti neoprávněnému přístupu a napadení systému.This thesis deals with methods of remote maintenance of microcontroller systems based on Atmel AVR family over the Ethernet interface and TCP/IP protocols. To create communication through TCP/IP, an embedded server NE-4100T is used. At the beginning, key features of the server and methods of handling with content of a program memory are discussed. The final solution is based on the bootloader method. It includes bootloader firmware and user program for PC. The hardware part covers design of interconnection electronics, DC-DC step down converter, real time clock and printed circuit board. The remote maintenance of program memory has been sucessfully solved, but the embedded server NE-4100T produces a problem with an auhentification without a sufficient solution.

    An Extended Model of a MEMS Gyroscope: Design and Identification

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    Práce se zabývá metodikou měření parametrů MEMS gyroskopů a stanovením vstupně-výstupního modelu. V úvodu je stručně rozebrán stávající přístup k modelování MEMS gyroskopů a určení jejich parametrů. Druhá část se podrobně věnuje metodice měření a identifikaci zdrojů nejistot, které ovlivňují odhad parametrů. V rámci metodiky měření jsou zdůrazněny kritické body a vliv jednotlivých zdrojů nejistot je ukázán na základě naměřených dat či simulací. Vlastnosti MEMS gyroskopů jsou prakticky demonstrovány na skupině různých typů snímačů. Výsledky ukazují významný vliv napájecího napětí na posun nuly gyroskopu a interního teplotního snímače. Tento jev může způsobit chybu srovnatelnou s teplotní závislostí či stochastickými vlastnostmi, ale není v literatuře popsán. Druhým jevem, který není stávajícími modely uvažován, je závislost širokopásmového šumu (ARW) na teplotě. Na základě těchto poznatků je v poslední části rozšířen běžně používaný model MEMS gyroskopu o závislost parametrů na napájecím napětí a závislost širokopásmového šumu na teplotě. Tvar modelu je zvolen s ohledem na jednoduché porovnání základních parametrů a v případě potřeby na snadné rozšíření o další vlivy.The thesis is aimed on measurement and modeling of MEMS gyroscopes based on input-output characteristics. The first part briefs the state of the art. The second part is dedicated to measurement methodology. Critical points and sources of uncertainty are discussed and evaluated using measurements or simulations. The last part shows key characteristics of MEMS gyroscopes based on the survey of a group of different sensor types. The results have revealed significant influence of supply voltage that causes bias drift of the gyroscope and bias drift of the internal temperature sensor. The error can be comparable to temperature drift; however, this effect is not addressed in the literature. The second observed effect is temperature dependency of angle random walk. In the last part, a general model of a MEMS gyroscope is rewritten to reflect observed effects. Moreover, the structure is selected to be easily extendable and the coefficients are expressed to allow a comparison of nominal parameters of different sensors.

    Stationary device for vibrodiagnostics of passing vehicle

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    On the base of the carried out measurement in 2013 and 2014, the stationary measurement system has been developed for vibrodiagnostics of railway vehicles. This system is currently in a trial operation in Prague's subway. The principle of the railway vehicle bogie diagnostics is based on noise and vibration measurement of a railway superstructure. The measurement system is self-contained – it saves the measured data of a passed train automatically, including identification of the trainset and the each wheelset. The measured data are evaluated in the frequency domain, where failure symptoms are identified. The measurement repeatability makes possible application of a neural network for detection of the failure symptoms. The next phase of this project will concern to the application of the neural network. The function of the developed device and the principle of failure detection are described in this paper. The existing results of the carried out measurement are presented too

    Generalized Poisson--Nernst--Planck-based physical model of O2_2 I LSM I YSZ electrode

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    The paper presents a generalized Poisson-Nernst-Planck model of an yttria-stabilized zirconia electrolyte developed from first principles of nonequilibrium thermodynamics which allows for spatial resolution of the space charge layer. It takes into account limitations in oxide ion concentrations due to the limited availability of oxygen vacancies. The electrolyte model is coupled with a reaction kinetic model describing the triple phase boundary with electron conducting lanthanum strontium manganite and gaseous phase oxygen. By comparing the outcome of numerical simulations based on different formulations of the kinetic equations with results of EIS and CV measurements we attempt to discern the existence of separate surface lattice sites for oxygen adatoms and O2- from the assumption of shared ones. Furthermore, we discern mass-action kinetics models from exponential kinetics models

    The role of actin isoforms in somatic embryogenesis in Norway spruce

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    <p>Abstract</p> <p>Background</p> <p>Somatic embryogenesis in spruce is a process of high importance for biotechnology, yet it comprises of orchestrated series of events whose cellular and molecular details are not well understood. In this study, we examined the role of actin cytoskeleton during somatic embryogenesis in Norway spruce line AFO 541 by means of anti-actin drugs.</p> <p>Results</p> <p>Application of low doses (50-100 nM) of latrunculin B (Lat B) during the maturation of somatic embryos predominantly killed suspensor cells while leaving the cells in meristematic centres alive, indicating differential sensitivity of actin in the two cell types. The treatment resulted in faster development of more advanced embryos into mature somatic embryos and elimination of insufficiently developed ones. In searching for the cause of the differential actin sensitivity of the two cell types, we analysed the composition of actin isoforms in the culture and isolated four spruce actin genes. Analysis of their expression during embryo maturation revealed that one actin isoform was expressed constitutively in both cell types, whereas three actin isoforms were expressed predominantly in suspensor cells and their expression declined during the maturation. The expression decline was greatly enhanced by Lat B treatment. Sequence analysis revealed amino-acid substitutions in the Lat B-binding site in one of the suspensor-specific actin isoforms, which may result in a different binding affinity for Lat B.</p> <p>Conclusions</p> <p>We show that manipulating actin in specific cell types in somatic embryos using Lat B treatment accelerated and even synchronized the development of somatic embryos and may be of practical use in biotechnology.</p

    The Response of Picea abies Somatic Embryos to UV-B Radiation Depends on the Phase of Maturation

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    Ultraviolet-B (UV-B) radiation is a key environmental signal which initiates diverse responses that affect the metabolism, development, and viability of plants. In keeping with our previous studies, we concentrated primarily on how UV-B radiation affects Norway spruce [Picea abies (L.) Karst.] somatic embryo maturation and how phenolics and polyamines (PAs) are linked to the defense response invoked by UV-B irradiation. We treated clusters of Norway spruce embryogenic culture (EC) with UV-B during the five stages of embryo maturation (early, cylindrical, precotyledonary, cotyledonary, and mature embryos). For the first time, we take an advantage of the unique environmental scanning electron microscope AQUASEM II to characterize somatic embryos in their native state. The severity of the irradiation effect on embryonal cell viability was shown to be dependent on the intensity of radiation as well as the stage of embryo development, and might be related to the formation of protoderm. The response of early embryos was characterized by an increase in malondialdehyde (MDA), a marked decrease in PA contents and a decline in phenolics. The reduced ability to activate the defense system seems to be responsible not only for the severe cell damage and decrease in viability but also for the inhibition of embryo development. The significant reduction in spermidine (Spd), which has been reported to be crucial for the somatic embryo development of several coniferous species, may be causally linked to the limited development of embryos. The pronounced decrease in cell wall-bound ferulic acid might correspond to failure of somatic embryos to reach more advanced stages of development. Embryos at later stages of development showed stress defense responses that were more efficient against UV-B exposure

    Análise de Política Externa e Política Externa Brasileira: trajetória, desafios e possibilidades de um campo de estudos

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    Jak se mění kvalita vody na odtoku z rybníků při jejich výlovu

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    The goal of this diploma thesis was to characterise the change of pond effluent quality during fish harvesting period. The change of water quality variables were measured and the pond draining stage at which fish harvesting activities affect most the quality of pond effluent was identified. Results and observations should help with the development of technology for retaining the sediment and nutrients discharged from ponds during fish harvest. The monitoring of pond effluent quality was carried out in twelve ponds managed by Krajské školní hospodářství České Budějovice in South Bohemian region. At different fish harvest phases, water temperature, concentration of dissolved oxygen, conductivity, turbidity and pH were measured in situ with a multiparametric probe YSI EXO 2. At the same time, water samples were also taken to quantify the concentration of suspended solids (SS), total phosphorus (TP), particulate and dissolved phosphorus (PP, DP) and total nitrogen (TN). Water samples were processed in the laboratories of the state enterprise Povodí Vltavy in České Budějovice. Our results confirmed that draining and fish harvest have significant influence on the quality of both the pond effluents and probably on the water bodies located downstream of the ponds. The largest changes of monitored parameters were caused by the time of active movement of fish and people in fish harvesting area. The active movements include setting the tanks for fish sorting, fish scaring, and seining. The highest concentrations of suspended solids, total phosphorus and total nitrogen were detected at the stage of catching fish with hand nets and surface outflow after the end of fish harvest. The changes of values during the fish harvest were considerable (% higher than pond water) and was fast. Therefore, best management practices aiming at reducing the concentration of SS, TP and TN may be implemented starting from the stage of fish netting until the closure of the pond outlet. Dissolved phosphorus has been identified as the key parameter causing eutrophication. The results of our study revealed that fish harvest is not so important problem from this point of view. During fish harvests obviously dominated particulated phosphorus which part was in average more than 99 %. The quality of effluent discharged during fish harvest was mainly influenced by the biomass and type of fish. Weather, water level regulation and type of outlet device influenced the effluent quality as well but at a lesser extent

    Protection of Forest, Sustainable Farming in Wood

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    Práce odevzdána pouze v elektronické podoběImport 29/09/2010V předložené práci je zpracován stručný popis a přehled lesů v Krušných horách, kdy tento je zaměřen na poškození lesů a jejich následné obnovení, jsou zde uvedeny i způsoby obnovení lesů, které doporučují odborníci, kteří se touto problematikou delší dobu zabývají. V úvodu jsou uvedeny druhy lesů a postupné znečišťování lesů od předválečného období do současnosti. Dále jsou zde uvedeny látky, které znečišťují lesní porost. V závěrečné části jsou uvedeny způsoby obnovení již poškozených lesů a k tomu náležející prostředky (dotace), které lze čerpat formou podpůrných fondů.The presented work deals with the brief description and survey of the forests in the Ore Mountains, which is focused on forest damage and their further reconstruction. There are shown even the ways of forest reconstruction, which are recommended by the experts, who have been interested in these issues for a long time. At the beginning there are introduced some kinds of forests and gradual polluting of the forests from the pre war period till nowadays. Next, there are mentioned the substances which contaminate the underbrush. In the closing part there are the ways of damaged forest renewal and belonging means [grants], which can be drawn upon relief funds.545 - Institut ekonomiky a systémů řízenídobř
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