Luminescence-Based Sensors for Aeronautical Applications

Pedras, Bruno; Orellana, Guillermo; Berberan‐Santos, Mário Nuno

doi:10.1007/4243_2019_11

Cited by 4 publications

(3 citation statements)

References 74 publications

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“…Dealing with this problem, the Orellana group at the University of Madrid has investigated sensors which measure changes in the extrinsic fluorescence of transition-metal-based complexes upon interaction with fluid molecules. As described in detail in a review article by this group [38], a number of luminescent sensors has been developed which are of potential interest in various aeronautic fields, including hydraulic fluid monitoring. Recently, our own group has been investigating fluorescence sensors, which use GaN/InGaN nanowire arrays on silicon and sapphire substrates as luminescent materials.…”

Section: Achievements and Possible Ways Forwardmentioning

confidence: 99%

Health Monitoring of Aviation Hydraulic Fluids Using Opto-Chemical Sensor Technologies

2020

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Passenger safety requires that in commercial airplanes hydraulic actuators be powered by fire-resistant hydraulic fluids. As a downside, such fluids are hygroscopic which means that these tend to accumulate humidity from the environment and that the dissolved humidity tends to produce acidity which can corrode all kinds of metallic components inside a hydraulic system. As such damage in safety-critical subsystems is hard to localize and expensive to repair, sensor technologies are required which allow the state of water contamination and fluid degradation to be routinely checked and necessary maintenance actions to be scheduled in a way that causes minimum flight interruptions. The paper reviews progress that has been made in developing such sensor systems and in commissioning these into practical flight operation. Sensor technologies that proved optimally adapted to this purpose are multi-channel non-dispersive (NDIR) systems working in the mid-infrared range. Additional options concern optical absorption sensors working in the near-infrared and visible ranges as well as fluorescence sensors.

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Section: Achievements and Possible Ways Forwardmentioning

confidence: 99%

Health Monitoring of Aviation Hydraulic Fluids Using Opto-Chemical Sensor Technologies

2020

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“…The gold standard of pH analysis is glass pH electrode, which can provide rapid, stable, and reliable readout in a wide pH range, which is proportional to sample pH. However, due to its significant size (>1 mm, even if miniaturized), susceptibility to electrical interferences, difficulty of sterilization and rigid design, glass electrodes are poorly suitable for biological samples containing cells [2,5]. Thus, new approaches to pH monitoring in solutions are in high demand.…”

Section: Introductionmentioning

confidence: 99%

New solid-state optochemical pH sensors for the analysis of cell bioenergetics

Zhdanov

2023

Optical Sensors 2023

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Monitoring pH and extracellular acidification in biological samples containing live mammalian cells can provide valuable information on the glycolytic activity and bioenergetic status of cells. Compared to pH electrodes, optochemical pH sensors look more advantageous, since they allow rapid, non-invasive parallel analysis of multiple samples with stable readout of pH. We have developed new fluorescent pH sensors based on hydrophobic protonable metal-free porphyrins (OEP and OEPK) embedded in a proton-permeable polymeric matrix together with a proton transfer agent. These pH sensors provide internally-referenced calibration-free operation, both in ratiometric intensity and lifetime based detection modes. Sensor development included optimization of the indicator dye and its photophysical characteristics, screening of different proton transfer agents to minimize sensor toxicity, tuning of protonation range and pKa, long-term storage stability and response time studies. Optimised pH sensor coatings were then deposited on plastic substrates (96-well microplates) and used for real-time monitoring of Extracellular Acidification Rate (ECAR) for cultured cancer cells and 3D spheroid structures on standard laboratory equipment (multi-label plate reader and confocal FLIM microscope). The advanced pH sensors tailored for use with biological samples have high potential for cell analysis and related applications.

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“…However, the Clark electrode exhibits some disadvantages that have hindered its further applications, such as oxygen consumption during measurements, which is detrimental in low-concentration oxygen detection, the requirement for repetitive calibration, replacement of electrode and electrolyte, and the large size of the electrode significantly limiting its usage in many biomedical applications. In recent years, photonic oxygen sensors have found new applications in the food industry for the quality control purposes [11], the pharmaceutical sector for drug discovery [12], in automotive and aviation for air conditioning [13], aquafarming for high-density production [14,15] and biomedical for imaging [16,17]. When oxygen-sensing probes (OSP) are optically excited, electrons absorb the incident photons' energy to transfer from the ground state to excited states.…”

Section: Introductionmentioning

confidence: 99%

Photonic-Based Time-Resolved Multipulse Oxygen Sensor

2022

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Oxygen is one of Earth's vital elements, and its accurate measurement is crucial in numerous scientific and medical applications. Photonic-based sensors have recently become the subject of great attention for oxygen measurements due to their highly promising characteristics. These include the lack of requirement for repetitive calibrations and replacement of parts, being contactless, their accuracy, and fast response, and the potential to fabricate such sensors in small sizes. Here, we develop a dissolved-oxygen sensor by integrating time-resolved photoluminescence spectroscopy employing an FPGA-controlled multi-pulse LED source and amplified fast photodetector mounted on a PCB, light-emitting platinum porphine complex embedded polystyrene molecular oxygen-sensing probe, and a two-site Stern-Volmer function for the sensing and calibration. The PCB excites the molecular probe with multiple 50 ns blue light pulses, and the emission lifetime is extracted using an exponential function based on the Levenberg-Marquardt nonlinear fitting. Complete characterization of the sensor, including its sensitivity, repeatability, stability, and response time, in addition to the temperature and altitude compensation, is implemented to achieve excellent dissolved-oxygen sensing functionality.

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Luminescence-Based Sensors for Aeronautical Applications

Cited by 4 publications

References 74 publications

Health Monitoring of Aviation Hydraulic Fluids Using Opto-Chemical Sensor Technologies

Health Monitoring of Aviation Hydraulic Fluids Using Opto-Chemical Sensor Technologies

New solid-state optochemical pH sensors for the analysis of cell bioenergetics

Photonic-Based Time-Resolved Multipulse Oxygen Sensor

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