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3 results on '"F. Feichtinger"'

1. Monitoring Physical Fluid Properties Using a Piezoelectric Tuning Fork Resonant Sensor

Author

A.O. Niedermayer, Bernhard Jakoby, Martin Heinisch, Thomas Voglhuber-Brunnmaier, and F. Feichtinger

Subjects
Materials science, Acoustics, 02 engineering and technology, Fuel analysis, 01 natural sciences, law.invention, 010309 optics, Resonator, Viscosity, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Metre, Viskosität, Tuning fork, Oil condition monitoring, Signal processing, Massendichte, High accuracy, Dynamic range, 020208 electrical & electronic engineering, Condition monitoring, Resonante Sensoren, General Medicine, General Chemistry, Akustische Sensoren, Piezoelectricity, Micro acoustic liquid sensor, Zustandsüberwachung, Low cross-sensitivity, Mass density
Abstract

For fluid analysis applications, such as oil condition monitoring, fuel quality, or gas concentration measurements, resonant sensors deliver an outstanding performance when signal processing is optimized and the fluid-mechanical model of the electromechanical resonator is suitable and accurate for the particular resonator. By combining recent advancements, significant improvements in accuracy, measurement speed, dynamic range, and suppression of cross-sensitivities could be achieved. These features enable the development of new solutions for a variety of measurement issues in industry and bio technology. In this contribution the performance of a highly universal evaluation system is demonstrated using a commercially available quartz crystal tuning fork resonator as sensing element for liquid viscosity and mass density. The obtained results are quantified with respect to an accurate lab bench viscosity and mass density meter. A significant advantage of this system is that it operates reliably and accurately even for strongly damped resonators. Therefore, the sensor elements can be used in a larger viscosity range than with alternative evaluation methods.

Published
2016
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2. Investigations of nitrogen fluxes and pools on a limestone site in the Alps.

Author

Herman F, Smidt S, Englisch M, Feichtinger F, Gerzabek M, Haberhauer G, Jandl R, Kalina M, and Zechmeister-Boltenstern S

Subjects
Altitude, Austria, Environmental Monitoring, Nitrogen chemistry, Nitrous Oxide analysis, Soil Pollutants analysis, Water chemistry, Water Pollutants analysis, Calcium Carbonate chemistry, Models, Theoretical, Nitrates analysis, Nitrogen analysis, Soil
Abstract

In the North Tyrolean Limestone Alps a site was investigated over a four-year period (1998-2001) in order to assess the nitrogen saturation status, the nitrogen budget (quantification of the net uptake of nitrogen by the canopy and of the nitrogen mineralization, nitrogen uptake from roots and N2O emission rates, proof of the origin of nitrate in the soil water with stable isotope analyses), and the effects of the actual nitrogen input on ground water quality. The main goals were to quantify the nitrogen input rate, the nitrogen pools in above-ground and below-ground compartments, nitrogen turnover processes in the soil as well as the output into the groundwater and into the atmosphere. The findings are based on continuous and discontinuous field measurements as well as on model results. While nitrogen input exceeded the Critical Loads of the WHO (1995), nitrogen deficiency and nutrient imbalances were verified by needle analyses. The atmospheric input of inorganic nitrogen was higher than the nitrogen output in 50 cm soil depth. A tracer experiment with 15N helped to prove that not more than half of the applied nitrate could be discharged. This allows the conclusion that nitrogen is stored in the system and that the site cannot yet be said to be saturated with nitrogen. The same result was also obtained by modelling. In addition, it was proved that the nitrogen discharge did not stem from deposition but from processes within the system.

Published
2002
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3. Water and nitrate fluxes at a forest site in the North Tyrolean Limestone Alps.

Author

Feichtinger F, Smidt S, and Klaghofer E

Subjects
Altitude, Austria, Calcium Carbonate, Environmental Monitoring, Rain, Nitrogen analysis, Trees, Water Movements
Abstract

The water balance for the site Mühleggerköpfl in the North Tyrolean Limestone Alps has been established to a soil depth of 50 cm. The evaporation amounts to 42% and deep percolation is 58% of the precipitation. The surface runoff was negligible and therefore the according nitrate fluxes as welL Soil water analysis revealed mean nitrate concentrations of 3 to 15 mg NO3 L(-1), depending on soil depth. The nitrate concentrations at 50 cm soil depth and the associated percolation rates led to NO3-N outputs of 15.9 kg NO3-N ha(-1) in the year 1999 and 7.9 kg NO3-N ha(-1) in the year 2000.

Published
2002
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