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Advanced measurements of a tip clearance flow are carried out in the large subsonic anechoic wind tunnel of the LMFA in Lyon. The experimental set-up is obtained by placing the airfoil between two plates into the potential core of a turbulent rectangular jet, the upper plate being the hub and the lower the casing. The jet that exits a converging nozzle has a 450 mm cross-stream width and a 200 mm height in the span-wise direction. An h=10 mm gap is maintained between the blade and the casing plate. The incoming free stream turbulence u’/U0 is 0.5%, and the flat plate boundary layer half a chord upstream of the airfoil leading edge is about 8 mm thick. Except for the thickness being halved, the configuration is the same as the one discussed by Jacob et al.1, I.J.A, 9(3), (2010) , and Camussi et al.2, J.F.M., 660, (2010): a M ~ 0.2 and Rec ~ 950000 jet flow past a NACA5510 airfoil with 15° angle of attack. Measurements are carried out in the region of the Tip Leakage Vortex (TLV) in order to characterise its unsteady velocity. Both 2D–2 Component and stereo Time Resolved PIV techniques are successfully applied in order to provide an insight into the low frequency content of the velocity field, that are compared to LDV measurements. This experiment corresponds to a novel type of configuration that has only been studied by Jacob et al. Moreover, the TR-PIV and specifically the stereo-TR PIV are quite new techniques that have not often been applied to such complex configurations at such high speeds. The benefits of the time resolution are promising for the understanding of such broadband noise sources. Among the findings, there is a low frequency oscillation of the TLV, whose mechanism is yet unclear but which does not seem to radiate into the far field. Additionally, a hump at medium and high frequencies (0.7 – 7 kHz) is found in the far field. It can also be related to time decay double space-time correlations.

Advanced measurements of a tip clearance flow are carried out in the large subsonic anechoic wind tunnel of the LMFA in Lyon. The experimental set-up is obtained by placing the airfoil between two plates into the potential core of a turbulent rectangular jet, the upper plate being the hub and the lower the casing. The jet that exits a converging nozzle has a 450 mm cross-stream width and a 200 mm height in the span-wise direction. An h=10 mm gap is maintained between the blade and the casing plate. The incoming free stream turbulence u’/U0 is 0.5%, and the flat plate boundary layer half a chord upstream of the airfoil leading edge is about 8 mm thick. Except for the thickness being halved, the configuration is the same as the one discussed by Jacob et al.1, I.J.A, 9(3), (2010) , and Camussi et al.2, J.F.M., 660, (2010): a M ~ 0.2 and Rec ~ 950000 jet flow past a NACA5510 airfoil with 15° angle of attack. Measurements are carried out in the region of the Tip Leakage Vortex (TLV) in order to characterise its unsteady velocity. Both 2D–2 Component and stereo Time Resolved PIV techniques are successfully applied in order to provide an insight into the low frequency content of the velocity field, that are compared to LDV measurements. This experiment corresponds to a novel type of configuration that has only been studied by Jacob et al. Moreover, the TR-PIV and specifically the stereo-TR PIV are quite new techniques that have not often been applied to such complex configurations at such high speeds. The benefits of the time resolution are promising for the understanding of such broadband noise sources. Among the findings, there is a low frequency oscillation of the TLV, whose mechanism is yet unclear but which does not seem to radiate into the far field. Additionally, a hump at medium and high frequencies (0.7 – 7 kHz) is found in the far field. It can also be related to time decay double space-time correlations.

This paper focuses on applications and electrical valorisation of microbial fuel cells (MFCs), a promising energy harvesting technique, suitable as clean power source to supply low power devices in wireless sensor networks (WSN) for environmental and agricultural monitoring. An MFC is a bioreactor that converts energy stored in chemical bonds of organic matter into electrical energy, through a series of reactions catalysed by microorganisms. An MFC can operate as bioreactor, as bioremediator and as biosensor. In the past decade, the evolution of low power electronics has made MFCs technology more attractive, because it has become suitable for low-power devices forming complete systems, such as the nodes of a WSN. Moreover, MFCs gained more interest because they can generate electric power while treating wastes. Unlike other fuel cells, MFCs can continuously generate clean energy at normal temperature and atmospheric pressure without any supplementary maintenance. Additionally, MFC may be used directly as a biosensor to analyse parameters like pH and temperature or arranged in the form of a cluster of devices to be use as a small power plant. A series of test was performed for the electrical valorisation of reactors as well as biosensor issues.

This paper focuses on applications and electrical valorisation of microbial fuel cells (MFCs), a promising energy harvesting technique, suitable as clean power source to supply low power devices in wireless sensor networks (WSN) for environmental and agricultural monitoring. An MFC is a bioreactor that converts energy stored in chemical bonds of organic matter into electrical energy, through a series of reactions catalysed by microorganisms. An MFC can operate as bioreactor, as bioremediator and as biosensor. In the past decade, the evolution of low power electronics has made MFCs technology more attractive, because it has become suitable for low-power devices forming complete systems, such as the nodes of a WSN. Moreover, MFCs gained more interest because they can generate electric power while treating wastes. Unlike other fuel cells, MFCs can continuously generate clean energy at normal temperature and atmospheric pressure without any supplementary maintenance. Additionally, MFC may be used directly as a biosensor to analyse parameters like pH and temperature or arranged in the form of a cluster of devices to be use as a small power plant. A series of test was performed for the electrical valorisation of reactors as well as biosensor issues.

Abstract The proton conductivity of SPEEK membranes in situ cross-linked by thermal treatment at 180 °C for various times was investigated by impedance spectroscopy. The conductivity measurements were made on fully humidified membranes between 25 and 65 °C and on membranes exposed to different relative humidity between 80 and 140 °C. The Ionic Exchange Capacity (IEC) was determined by acid-base titration and the water uptake by gravimetry. The proton conductivity was determined as function of temperature, IEC, degree of cross-linking and hydration number. A curve of proton conductivity vs. hydration number allows predicting that in order to reach a value of 0.1 S/cm at 100 °C a hydration number above 20 is necessary. The measured conductivity at this temperature is 0.16 S/cm for a hydration number of 60.

Abstract The proton conductivity of SPEEK membranes in situ cross-linked by thermal treatment at 180 °C for various times was investigated by impedance spectroscopy. The conductivity measurements were made on fully humidified membranes between 25 and 65 °C and on membranes exposed to different relative humidity between 80 and 140 °C. The Ionic Exchange Capacity (IEC) was determined by acid-base titration and the water uptake by gravimetry. The proton conductivity was determined as function of temperature, IEC, degree of cross-linking and hydration number. A curve of proton conductivity vs. hydration number allows predicting that in order to reach a value of 0.1 S/cm at 100 °C a hydration number above 20 is necessary. The measured conductivity at this temperature is 0.16 S/cm for a hydration number of 60.

This paper focuses on microbial fuel cell (MFC) waste valorization, electricity generation and practical applications. A custom electronic analyzer dedicated to MFCs is presented. The measuring system allows to set up a complete electrical characterization of a microbial fuel cell, useful to facilitate and accurately analyze the charge and discharge phase of an MFC. Moreover, it allows power performance analysis and measurement of any kind of MFC typology, using a custom software, which automatically sets up a series of tests over a long period of time. Electronics design and a flow diagram of the measuring instrument project are provided. MFCs are a zero-emission energy harvesting technology: a bioreactor that converts energy stored in chemical bonds of organic compounds into electrical energy. Due to these properties, MFCs could be useful to a wide range of applications in the context of bio-reactions, bio-remediation or bio-sensing.