| 1. |
- Domènech-Gil, Guillem, Mr. Doctor, et al.
(author)
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Efficient Methane Monitoring with Low-Cost Chemical Sensorsand Machine Learning
- 2024
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Conference paper (peer-reviewed)abstract
- We present a method to monitor methane at atmospheric concentrations with errors inthe order of tens of parts per billion. We use machine learning techniques and periodic calibrationswith reference equipment to quantify methane from the readings of an electronic nose. The resultsobtained demonstrate versatile and robust solution that outputs adequate concentrations in a varietyof different cases studied, including indoor and outdoor environments with emissions arising fromnatural or anthropogenic sources. Our strategy opens the path to a wide-spread use of low-costsensor system networks for greenhouse gas monitoring.
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| 2. |
- Domènech-Gil, Guillem, Mr. Doctor, et al.
(author)
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Electronic Nose for Improved Environmental Methane Monitoring
- 2024
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In: Environmental Science and Technology. - : AMER CHEMICAL SOC. - 0013-936X .- 1520-5851. ; 58, s. 352-361
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Journal article (peer-reviewed)abstract
- Reducing emissions of the key greenhouse gas methane (CH4) is increasingly highlighted as being important to mitigate climate change. Effective emission reductions require cost-effective ways to measure CH4 to detect sources and verify that mitigation efforts work. We present here a novel approach to measure methane at atmospheric concentrations by means of a low-cost electronic nose strategy where the readings of a few sensors are combined, leading to errors down to 33 ppb and coefficients of determination, R-2, up to 0.91 for in situ measurements. Data from methane, temperature, humidity, and atmospheric pressure sensors were used in customized machine learning models to account for environmental cross-effects and quantify methane in the ppm-ppb range both in indoor and outdoor conditions. The electronic nose strategy was confirmed to be versatile with improved accuracy when more reference data were supplied to the quantification model. Our results pave the way toward the use of networks of low-cost sensor systems for the monitoring of greenhouse gases.
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| 3. |
- Andersson, Mike, 1977-, et al.
(author)
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Recent progress in silicon carbide field effect gas sensors
- 2020. - 2
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In: Semiconductor gas sensors. - Oxford : Woodhead Publishing Limited. - 9780081025598 ; , s. 309-346
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Book chapter (peer-reviewed)abstract
- The introduction of silicon carbide as the semiconductor in gas-sensitive field effect devices has disruptively improved this sensor platform extending the operation temperature to more than 600 °C with an increased number of detectable gases. Here, we review recent progress in research and applications, starting with transducer and detection mechanisms, presenting new material combinations as sensing layers for improved selectivity and detection limits down to subparts per billion. We describe how temperature cycled operation combined with advanced data evaluation enables one sensor to act as a sensor array thereby vastly improving selectivity. Field tests require advanced packaging, which is described, and examples of possible applications like selective detection of ammonia for urea injection control in diesel exhausts and toxic volatile organic compounds for indoor air quality monitoring and control are given.
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| 4. |
- Bastuck, Manuel, et al.
(author)
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Low-cost chemical gas sensors for selective formaldehyde quantification at ppb-level in field tests
- 2017
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Conference paper (peer-reviewed)abstract
- Data from a silicon carbide based field-effect transistor were recorded over a period of nine days in a ventilated school room. For enhanced sensitivity and selectivity especially to formaldehyde, porous iridium on pulsed laser deposited tungsten trioxide was used as sensitive layer, in combination with temperature cycled operation and subsequent multivariate data processing techniques. The sensor signal was compared to reference measurements for formaldehyde concentration, CO2 concentration, temperature, and relative humidity. The results show a distinct pattern for the reference formaldehyde concentration, arising from the day/night cycle. Taking this into account, the projections of both principal component analysis and partial least squares regression lead to almost the same result concerning correlation to the reference. The sensor shows cross-sensitivity to an unidentified component of human activity, presumably breath, and, possibly, to other compounds appearing together with formaldehyde in indoor air. Nevertheless, the sensor is able to detect and partially quantify formaldehyde below 40 ppb with a correlation to the reference of 0.48 and negligible interference from ambient temperature or relative humidity.
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| 5. |
- Bastuck, Manuel, et al.
(author)
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UV-assisted gate bias cycling in gas-sensitive field-effect transistors
- 2018
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In: Proceedings. - Basel Switzerland : MDPI. - 2504-3900. ; 2:13
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Journal article (peer-reviewed)abstract
- Static and dynamic responses of a silicon carbide field-effect transistor gas sensor have been investigated at two different gate biases in several test gases. Especially the dynamic effects are gas dependent and can be used for gas identification. The addition of ultraviolet light reduces internal electrical relaxation effects, but also introduces new, temperature-dependent effects.
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| 6. |
- Casalinuovo, Silvia, et al.
(author)
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3D-Printed Face Mask with Integrated Sensors as Protective and Monitoring Tool
- 2023
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In: Sensors and Microsystems. - Cham : Springer Nature Switzerland. - 9783031257087 - 9783031257063
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Conference paper (peer-reviewed)abstract
- The outbreak of the recent Covid-19 pandemic changed many aspects of our daily life, such as the constant wearing of face masks as protection from virus transmission risks. Furthermore, it exposed the healthcare system’s fragilities, showing the urgent need to design a more inclusive model that takes into account possible future emergencies, together with population’s aging and new severe pathologies. In this framework, face masks can be both a physical barrier against viruses and, at the same time, a telemedical diagnostic tool. In this paper, we propose a low-cost, 3D-printed face mask able to protect the wearer from virus transmission, thanks to internal FFP2 filters, and to monitor the air quality (temperature, humidity, CO2) inside the mask. Acquired data are automatically transmitted to a web terminal, thanks to sensors and electronics embedded in the mask. Our preliminary results encourage more efforts in these regards, towards rapid, inexpensive and smart ways to integrate more sensors into the mask’s breathing zone in order to use the patient’s breath as a fingerprint for various diseases.
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| 7. |
- Casalinuovo, Silvia, et al.
(author)
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AuNP-coated cotton as VOC sensor for disease detection from breath
- 2023
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In: Proceedings of SIE 2022. - Cham : Springer Nature Switzerland. - 9783031260667 - 9783031260650
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Conference paper (peer-reviewed)abstract
- The COVID-19 pandemic outbreak, declared in March 2020, has led to several behavioral changes in the general population, such as social distancing and mask usage among others. Furthermore, the sanitary emergency has stressed health system weaknesses in terms of disease prevention, diagnosis, and cure. Thus, smart technologies allowing for early and quick detection of diseases are called for. In this framework, the development of point-of-care devices can provide new solutions for sanitary emergencies management. This work focuses on the development of useful tools for early disease diagnosis based on nanomaterials on cotton substrates, to obtain a low-cost and easy-to-use detector of breath volatiles as disease markers. Specifically, we report encouraging experimental results concerning acetone detection through impedance measurements. Such findings can pave the way to the implementation of VOCs (Volatile Organic Compounds) sensors into smart and user friendly diagnostic devices.
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| 8. |
- Casalinuovo, Silvia, et al.
(author)
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Cotone funzionalizzato con nanoparticelle d'oro come promettente substrato flessibile ed ecologico per il rilevamento impedometrico di COV [Gold Nanoparticles-Functionalized Cotton as Promising Flexible and Green Substrate for Impedometric VOC Detection]
- 2023
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In: Materials. - : MDPI. - 1996-1944. ; 16
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Journal article (peer-reviewed)abstract
- Questo lavoro si concentra sulla possibile applicazione di nanoparticelle d'oro su tessuti di cotone flessibili come substrati sensibili all'acetone e all'etanolo mediante misurazioni di impedenza. Nello specifico, nanoparticelle d'oro (NP Au) funzionalizzate con citrato e polivinilpirrolidone (PVP) sono state sintetizzate utilizzando procedure verdi e consolidate e depositate su tessuto di cotone. Una caratterizzazione strutturale e morfologica completa è stata condotta utilizzando la spettroscopia UV-VIS e infrarossa a trasformata di Fourier (FT-IR), la microscopia a forza atomica (AFM) e la microscopia elettronica a scansione (SEM). Una caratterizzazione dielettrica dettagliata del substrato vuoto ha rivelato effetti di polarizzazione interfacciale legati sia alle NP Au che alla loro specifica funzionalizzazione superficiale. Ad esempio, rivestendo interamente il tessuto di cotone (ovvero creando una matrice più isolante), è stato riscontrato che il PVP aumenta la resistenza del campione, ovvero diminuisce l'interconnessione elettrica delle NP Au rispetto al campione funzionalizzato con citrato. Tuttavia, è stato osservato che la funzionalizzazione del citrato ha fornito una distribuzione uniforme delle NP Au, che ha ridotto la loro spaziatura e, quindi, facilitato il trasporto degli elettroni. Per quanto riguarda il rilevamento dei composti organici volatili (COV), le misurazioni della spettroscopia di impedenza elettrochimica (EIS) hanno mostrato che il legame idrogeno e la risultante impedenza di migrazione protonica sono fondamentali per distinguere l'etanolo dall'acetone.
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| 9. |
- Casalinuovo, Silvia, et al.
(author)
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Measurements of Exhaled CO2 Through a Novel Telemedicine Tool
- 2023
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In: Lecture Notes in Electrical Engineering, vol 1113. Springer, Cham.. - : Springer Nature. - 9783031487101 - 9783031487118 ; , s. 396-401
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Book chapter (peer-reviewed)abstract
- This paper proposes a telemedicine tool (complete of hardware, software and 3D printed face mask) for analyzing exhaled carbon dioxide (CO2) levels. Our interest in CO2 pattern is due to its correlation to psychological and physiological health status. To achieve this information, we developed a customized printed circuit board equipped with a CO2 sensor for breath analysis, a microcontroller, a WiFi module for data transmission, and a battery for enabling an autonomous device. We also developed an interactive web page for the users and a database for daily remote data management. The device was tested on two healthy subjects of different ages and with different lifestyles. The results highlighted that the younger subject presents increased CO2 values as a direct link to a more active life. We consider these promising results for testing our device on a major cohort of observational studies.
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| 10. |
- Casalinuovo, Silvia, et al.
(author)
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Questioning Breath: A Digital Dive into CO2 Levels
- 2024
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Conference paper (peer-reviewed)abstract
- This work presents a smart mask for real-time monitoring of carbon dioxide (CO2) levels asa reference tool for diagnosis, sports training and mental health status. A printed circuit board wasprojected and fabricated to gain data with real-time visualization and storage on a database, enablingremote monitoring as a needed skill for telemedicine purposes. The electronics were inserted in awearable device—shaped like a mask—and 3D-printed with biocompatible materials. The wholedevice was used for analyzing CO2 on a breath volunteer in three kinds of measurement.
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