Electronic Nose as an NDT Tool for Aerospace Industry

AbstractArtificial olfaction is an emerging technology aiming to develop tools for easy, rapid and mobile gas mixture analysis. So far, its application to several application fields is under investigation with some commercial solution already deployed. In this work we present the results of the development process for an electronic nose devised for NDT in aerospace industry focusing on its pattern recognition stage

Combining Real Time Classifiers for Fast and Reliable Electronic Nose Response Analysis for Aerospace NDTs

AbstractFast response and reliability are a prerogative in non- destructive tests s p e c i f i c a l l y in aerospace industry for safety and efficiency reasons. Currently, composite panels bonding, in green aircraft concept, is lacking a validated NDT technique for the bond quality. E-noses equipped with PARC algorithms appear a promising choice to acquire speedily a complete pattern response maximizing reliability. In this paper, combining real time classifiers, we show how to obtain a rapid first- hand response with the possibility of increasing accuracy awaiting for the end of the e-nose measurement cycle. A reject option is casted on the base of classifier self-perceived reliability to nullify false negatives while keeping the false positive rate at minimum

Low-processing data enrichment and calibration for PM2.5 low-cost sensors

Particulate matter (PM) in air has been proven to be hazardous to human health. Here we focused on analysis of PM data we obtained from the same campaign which was presented in our previous study. Multivariate linear and random forest models were used for the calibration and analysis. In our linear regression model the inputs were PM, temperature and humidity measured with low-cost sensors, and the target was the reference PM measurements obtained from SEPA in the same timeframe

Whole-brain functional imaging to highlight differences between the diurnal and nocturnal neuronal activity in zebrafish larvae

Most living organisms show highly conserved physiological changes following a 24-hour cycle which goes by the name of circadian rhythm. Among experimental models, the effects of light-dark cycle have been recently investigated in the larval zebrafish. Owing to its small size and transparency, this vertebrate enables optical access to the entire brain. Indeed, the combination of this organism with light-sheet imaging grants high spatio-temporal resolution volumetric recording of neuronal activity. This imaging technique, in its multiphoton variant, allows functional investigations without unwanted visual stimulation. Here, we employed a custom two-photon light-sheet microscope to study whole-brain differences in neuronal activity between diurnal and nocturnal periods in larval zebrafish. We describe for the first time an activity increase in the low frequency domain of the pretectum and a frequency-localised activity decrease of the anterior rhombencephalic turning region during the nocturnal period. Moreover, our data confirm a nocturnal reduction in habenular activity. Furthermore, whole-brain detrended fluctuation analysis revealed a nocturnal decrease in the self-affinity of the neuronal signals in parts of the dorsal thalamus and the medulla oblongata. Our data show that whole-brain nonlinear light-sheet imaging represents a useful tool to investigate circadian rhythm effects on neuronal activity.Comment: 18 pages, 6 figure

Cooperative 3D Air Quality Assessment with Wireless Chemical Sensing Networks

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Effects of excitation light polarization on fluorescence emission in two-photon light-sheet microscopy

Light-sheet microscopy (LSM) is a powerful imaging technique that uses a planar illumination oriented orthogonally to the detection axis. Two-photon (2P) LSM is a variant of LSM that exploits the 2P absorption effect for sample excitation. The light polarization state plays a significant, and often overlooked, role in 2P absorption processes. The scope of this work is to test whether using different polarization states for excitation light can affect the detected signal levels in 2P LSM imaging of typical biological samples with a spatially unordered dye population. Supported by a theoretical model, we compared the fluorescence signals obtained using different polarization states with various fluorophores (fluorescein, EGFP and GCaMP6s) and different samples (liquid solution and fixed or living zebrafish larvae). In all conditions, in agreement with our theoretical expectations, linear polarization oriented parallel to the detection plane provided the largest signal levels, while perpendicularly-oriented polarization gave low fluorescence signal with the biological samples, but a large signal for the fluorescein solution. Finally, circular polarization generally provided lower signal levels. These results highlight the importance of controlling the light polarization state in 2P LSM of biological samples. Furthermore, this characterization represents a useful guide to choose the best light polarization state when maximization of signal levels is needed, e.g. in high-speed 2P LSM.Comment: 16 pages, 4 figures. Version of the manuscript accepted for publication on Biomedical Optics Expres