| 1. |
- Klason, Peter, et al.
(författare)
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A speed of sound based feed water temperature sensor
- 2012
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Ingår i: 9th International Temperature Symposium on Temperature. - : AIP. ; , s. 925-930
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Konferensbidrag (refereegranskat)abstract
- Controlling thermal power in the feed water line of a power plant presupposes both accurate flow and temperature measurement. In this application the temperature measurement is usually a single Pt-100. This results in a measurement error of several kelvin. In this study we have investigated two different sensors based on the speed of sound (SoS) in the flowing medium for measuring the average temperature across a flow pipe cross-section. This is a task within the on-going European research project called ENG-06. The two SoS-based temperature measuring sensors were investigated under laboratory conditions. Investigations were done using both homogenous and non-homogenous temperature distributions with temperature differences up to 25 K. In addition the influence of pressure (50-200 kPa) and flow rates (0.5-2 m/s) on the SoS devices were also investigated. Our results show that the SoS-based temperature principle is working. Furthermore, depending on the measurement conditions a SoS temperature measurement device significantly can reduce the deviation to the reference sensor compared with a single Pt-100 sensor. Relative reductions in the deviation to the reference of 20-85 % were possible to achieve. This opens for the possibility of increasing the energy efficiency in power plants as aimed for in the ENG-06 project.
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| 2. |
- Klason, Peter, et al.
(författare)
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Measuring Temperature in Pipe Flow with Non-Homogeneous Temperature Distribution
- 2014
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Ingår i: International journal of thermophysics. - : Springer Science and Business Media LLC. - 0195-928X .- 1572-9567. ; 35:3-4, s. 712-724
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Tidskriftsartikel (refereegranskat)abstract
- Accurate temperature measurements in flow lines are critical for many industrial processes. It is normally more a rule than an exception in such applications to obtain water flows with inhomogeneous temperature distributions. In this paper, a number of comparisons were performed between different 100 ohm platinum resistance thermometer (Pt-100) configurations and a new speed-of-sound-based temperature sensor used to measure the average temperature of water flows with inhomogeneous temperature distributions. The aim was to achieve measurement deviations lower than 1 K for the temperature measurement of water flows with inhomogeneous temperature distributions. By using a custom-built flow injector, a water flow with a hot-water layer on top of a cold-water layer was created. The temperature difference between the two layers was up to 32 K. This study shows that the deviations to the temperature reference for the average temperature of four Pt-100s, the multisensor consisting of nine Pt-100s, and the new speed-of-sound sensors are remarkably lower than the deviation for a single Pt-100 under the same conditions. The aim of reaching a deviation lower than 1 K was achieved with the speed-of-sound sensors, the configuration with four Pt-100s, and the multisensor. The promising results from the speed-of sound temperature sensors open the possibility for an integrated flow and temperature sensor. In addition, the immersion depth of a single Pt-100 was also investigated at three different water temperatures.
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| 3. |
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| 4. |
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| 5. |
- Klason, Peter, et al.
(författare)
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Temperature measurement in flow pipes : Comparison with single Pt-100 and multisensors
- 2013
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Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X. - 9780735411784 ; , s. 987-992
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Konferensbidrag (refereegranskat)abstract
- Accurate temperature measurements in flow lines are critical for many industrial processes. It is normally more a rule than an exception in such applications to obtain water flows with in-homogenous temperature distributions. In this paper a number of comparisons between different Pt-100 configurations used to measure the average temperature of water flows with in-homogenous temperature distributions were studied. By using a custom-built flow injector a water flow with a hot water layer on top of a cold water layer was created. The temperature difference between the two layers was up to 32K. The average temperature from a custom-built multiple Pt-100 sensors (consisting of 9 Pt-100) was used as reference. Our study shows that for a 32 K temperature difference between the two layers the deviation to the references decreased from about 4 K to 1 K by taking the average temperature of 4 Pt-100 mounted in the same pipe plane (90° apart) instead of a single Pt-100. Overall the deviation to the temperature reference for the average temperature of 4 Pt-100 is remarkable lower than the deviation for a single Pt-100 under the same conditions. In addition the immersion depth of a single Pt-100 was also investigated at three different water temperatures.
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| 6. |
- Merlone, Andrea, et al.
(författare)
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A new challenge for meteorological measurements : The meteoMet project-Metrology for meteorology
- 2013
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Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X .- 1551-7616. - 9780735411784 ; , s. 1030-1035
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Konferensbidrag (refereegranskat)abstract
- Climate change and its consequences require immediate actions in order to safeguard the environment and economy in Europe and in the rest of world. Aiming to enhance data reliability and reduce uncertainties in climate observations, a joint research project called MeteoMet-Metrology for Meteorology started in October 2011 coordinated by the Italian Istituto Nazionale di Ricerca Metrologica (INRiM). The project is focused on the traceability of measurements involved in climate change: surface and upper air measurements of temperature, pressure, humidity, wind speed and direction, solar irradiance and reciprocal influences between measurands. This project will provide the first definition at the European level of validated climate parameters with associated uncertainty budgets and novel criteria for interpretation of historical data series. The big challenge is the propagation of a metrological measurement perspective to meteorological observations. When such an approach will be adopted the requirement of reliable data and robust datasets over wide scales and long terms could be better met.
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| 7. |
- Al-Hilli, Safaa, 1965, et al.
(författare)
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Zinc oxide nanorods grown on two-dimensional macroporous periodic structures and plane Si as a pH sensor
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:1, s. 014302-014309
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Tidskriftsartikel (refereegranskat)abstract
- pH determination is a strong prerequisite for many biochemical and biological processes. We used two methods, namely, the electrochemical potential method (experimental) and site binding method (theoretical), to study the sensitivity of zinc oxide (ZnO) nanorods grown on two-dimensional macroporous periodic structures (2DMPPS) (p-and n-type) and plane n-type Si substrates for use as an intracellular pH sensing device. The dimension of these nanorods varied in radius between 50 and 300 nm and lengths of 1–10 μm. We found that the sensitivity of ZnO nanorods increases with reductions in size, from 35 mV/pH for D = 300 nm and L = 10 μm, to 58 mV/pH for D = 50 nm and L = 1 μm, using the site binding model. The experimental electrochemical potential difference for the ZnO nanorods working electrode versus Ag/AgCl reference electrode showed a high sensitivity range for ZnO nanorods grown on 2DMPPS n-Si substrate as compared to plane n-Si at room temperature for pH ranging from 4 to 12 in buffer and NaCl solutions
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| 9. |
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| 10. |
- Bano, Nargis, et al.
(författare)
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Study of Radiative Defects Using Current-Voltage Characteristics in ZnO Rods Catalytically Grown on 4H-p-SiC
- 2010
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Ingår i: JOURNAL OF NANOMATERIALS. - : Hindawi. - 1687-4110 .- 1687-4129. ; 2010
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Tidskriftsartikel (refereegranskat)abstract
- High-quality ZnO rods were grown by the vapour-liquid-solid (VLS) technique on 4H-p-SiC substrate. The current transport mechanisms of the diodes at room temperature (RT) have been explained in term of the space-charge-limited current model based on the energy band diagram of ZnO rods/4H-p-SiC heterostructure. The tunneling mechanism via deep-level states was found to be the main conduction process at low-applied voltage but at trap-filled limit voltage VTFL all traps are filled and the space-charge-limited current conduction dominated the current transport. From the RT current voltage measurements, the energy of the deep level trap and the trap concentration were obtained as ∼0.24±0.02eV and 4.4×1018cm−3, respectively. The deep level states observed correspond to zinc interstitial (Zni ), responsible for the violet emission.
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