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Open access

Petr Sedlak, Pavel Tofel, Vlasta Sedlakova, Jiri Majzner, Josef Sikula and Lech Hasse

Ultrasonic Spectroscopy of Silicon Single Crystal

Specimens of Si single crystals with different crystal orientation [100] and [110] were studied by Electro-Ultrasonic Spectroscopy (EUS) and Resonant Ultrasonic Spectroscopy (RUS). A silicon single crystal is an anisotropic crystal, so its properties are different in different directions in the material relative to the crystal orientation. EUS is based on interaction of two signals: an electric AC signal and an ultrasonic signal, which are working on different frequencies. The ultrasonic wave affects the charge carriers' transport in the structures and the intermodulation electrical signal which is created due to the interaction between the ultrasonic wave and charge carriers, is proportional to the density of structural defects. RUS enables to measure natural frequencies of free elastic vibrations of a simply shaped specimen by scanning a selected frequency range including the appropriate resonances of the measured specimens.

Open access

Leonardo Montagnani, Thomas Grünwald, Andrew Kowalski, Ivan Mammarella, Lutz Merbold, Stefan Metzger, Pavel Sedlák and Lukas Siebicke

Abstract

In eddy covariance measurements, the storage flux represents the variation in time of the dry molar fraction of a given gas in the control volume representative of turbulent flux. Depending on the time scale considered, and on the height above ground of the measurements, it can either be a major component of the overall net ecosystem exchange or nearly negligible. Instrumental configuration and computational procedures must be optimized to measure this change at the time step used for the turbulent flux measurement. Three different configurations are suitable within the Integrated Carbon Observation System infrastructure for the storage flux determination: separate sampling, subsequent sampling and mixed sampling. These configurations have their own advantages and disadvantages, and must be carefully selected based on the specific features of the considered station. In this paper, guidelines about number and distribution of vertical and horizontal sampling points are given. Details about suitable instruments, sampling devices, and computational procedures for the quantification of the storage flux of different GHG gases are also provided.

Open access

Jiří Čupera, Pavel Sedlák, František Bauer and Martin Fajman

Shrnutí

Članek popisuje možnost využiti dat ze sběrnice CAN nebo ISO-BUS pro tahove zkoušky traktoru. Zkoušeni sestavalo z polnich a laboratornich zkoušek, před vlastnim polnim měřenim byl motor zkoušen na dynamometru. Parametry odečtene ze sběrnice CAN byly validovany externimi snimači a byla vyhodnocena jejich chyba. Na zakladě měřeni bylo shledano, že chyba prezentovaneho zatiženi odečteneho ze sběrnice CAN je velmi vyznamna. Pro zpřesněni teto hodnoty je nutne vytvořit regresni funkci. Model byl dale ověřen a byla vypočtena nejistota. Bylo shledano, že pro zahrnuti parametrů sběrnice CAN do testovacich procedur je nutne provest předchozi statistickou analyzu parametrů.

Open access

Simone Sabbatini, Ivan Mammarella, Nicola Arriga, Gerardo Fratini, Alexander Graf, Lukas Hörtnagl, Andreas Ibrom, Bernard Longdoz, Matthias Mauder, Lutz Merbold, Stefan Metzger, Leonardo Montagnani, Andrea Pitacco, Corinna Rebmann, Pavel Sedlák, Ladislav Šigut, Domenico Vitale and Dario Papale

Abstract

The eddy covariance is a powerful technique to estimate the surface-atmosphere exchange of different scalars at the ecosystem scale. The EC method is central to the ecosystem component of the Integrated Carbon Observation System, a monitoring network for greenhouse gases across the European Continent. The data processing sequence applied to the collected raw data is complex, and multiple robust options for the different steps are often available. For Integrated Carbon Observation System and similar networks, the standardisation of methods is essential to avoid methodological biases and improve comparability of the results. We introduce here the steps of the processing chain applied to the eddy covariance data of Integrated Carbon Observation System stations for the estimation of final CO2, water and energy fluxes, including the calculation of their uncertainties. The selected methods are discussed against valid alternative options in terms of suitability and respective drawbacks and advantages. The main challenge is to warrant standardised processing for all stations in spite of the large differences in e.g. ecosystem traits and site conditions. The main achievement of the Integrated Carbon Observation System eddy covariance data processing is making CO2 and energy flux results as comparable and reliable as possible, given the current micrometeorological understanding and the generally accepted state-of-the-art processing methods.

Open access

Petr Sedlak, Petr Kubersky, Pavel Skarvada, Ales Hamacek, Vlasta Sedlakova, Jiri Majzner, Stanislav Nespurek and Josef Sikula

Abstract

Electrochemical amperometric gas sensors represent a well-established and versatile type of devices with unique features: good sensitivity and stability, short response/recovery times, and low power consumption. These sensors operate at room temperature, and therefore have been applied in monitoring air pollutants and detection of toxic and hazardous gases in a number of areas. Some drawbacks of classical electrochemical sensors are overcome by the solid polymer electrolyte (SPE) based on ionic liquids. This work presents evaluation of an SPE-based amperometric sensor from the point of view of current fluctuations. The sensor is based on a novel three-electrode sensor platform with solid polymer electrolytes containing ionic liquid for detection of nitrogen dioxide − a highly toxic gas that is harmful to the environment and presenting a possible threat to human health even at low concentrations. The paper focuses on using noise measurement (electric current fluctuation measurement) for evaluation of electrochemical sensors which were constructed by different fabrication processes: (i) lift-off and drop-casting technology, (ii) screen printing technology on a ceramic substrate and (iii) screen printing on a flexible substrate.

Open access

Daniela Franz, Manuel Acosta, Núria Altimir, Nicola Arriga, Dominique Arrouays, Marc Aubinet, Mika Aurela, Edward Ayres, Ana López-Ballesteros, Mireille Barbaste, Daniel Berveiller, Sébastien Biraud, Hakima Boukir, Timothy Brown, Christian Brümmer, Nina Buchmann, George Burba, Arnaud Carrara, Allessandro Cescatti, Eric Ceschia, Robert Clement, Edoardo Cremonese, Patrick Crill, Eva Darenova, Sigrid Dengel, Petra D’Odorico, Gianluca Filippa, Stefan Fleck, Gerardo Fratini, Roland Fuß, Bert Gielen, Sébastien Gogo, John Grace, Alexander Graf, Achim Grelle, Patrick Gross, Thomas Grünwald, Sami Haapanala, Markus Hehn, Bernard Heinesch, Jouni Heiskanen, Mathias Herbst, Christine Herschlein, Lukas Hörtnagl, Koen Hufkens, Andreas Ibrom, Claudy Jolivet, Lilian Joly, Michael Jones, Ralf Kiese, Leif Klemedtsson, Natascha Kljun, Katja Klumpp, Pasi Kolari, Olaf Kolle, Andrew Kowalski, Werner Kutsch, Tuomas Laurila, Anne de Ligne, Sune Linder, Anders Lindroth, Annalea Lohila, Bernhard Longdoz, Ivan Mammarella, Tanguy Manise, Sara Maraňón Jiménez, Giorgio Matteucci, Matthias Mauder, Philip Meier, Lutz Merbold, Simone Mereu, Stefan Metzger, Mirco Migliavacca, Meelis Mölder, Leonardo Montagnani, Christine Moureaux, David Nelson, Eiko Nemitz, Giacomo Nicolini, Mats B. Nilsson, Maarten Op de Beeck, Bruce Osborne, Mikaell Ottosson Löfvenius, Marian Pavelka, Matthias Peichl, Olli Peltola, Mari Pihlatie, Andrea Pitacco, Radek Pokorný, Jukka Pumpanen, Céline Ratié, Corinna Rebmann, Marilyn Roland, Simone Sabbatini, Nicolas P.A. Saby, Matthew Saunders, Hans Peter Schmid, Marion Schrumpf, Pavel Sedlák, Penelope Serrano Ortiz, Lukas Siebicke, Ladislav Šigut, Hanna Silvennoinen, Guillaume Simioni, Ute Skiba, Oliver Sonnentag, Kamel Soudani, Patrice Soulé, Rainer Steinbrecher, Tiphaine Tallec, Anne Thimonier, Eeva-Stiina Tuittila, Juha-Pekka Tuovinen, Patrik Vestin, Gaëlle Vincent, Caroline Vincke, Domenico Vitale, Peter Waldner, Per Weslien, Lisa Wingate, Georg Wohlfahrt, Mark Zahniser and Timo Vesala

Abstract

Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System combines carbon and greenhouse gas (GHG; CO2, CH4, N2O, H2O) observations within the atmosphere, terrestrial ecosystems and oceans. High-precision measurements are obtained using standardised methodologies, are centrally processed and openly available in a traceable and verifiable fashion in combination with detailed metadata. The Integrated Carbon Observation System ecosystem station network aims to sample climate and land-cover variability across Europe. In addition to GHG flux measurements, a large set of complementary data (including management practices, vegetation and soil characteristics) is collected to support the interpretation, spatial upscaling and modelling of observed ecosystem carbon and GHG dynamics. The applied sampling design was developed and formulated in protocols by the scientific community, representing a trade-off between an ideal dataset and practical feasibility. The use of open-access, high-quality and multi-level data products by different user communities is crucial for the Integrated Carbon Observation System in order to achieve its scientific potential and societal value.