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- Rödjegård, Henrik, 1974-, et al.
(författare)
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Drowsy Driver & Child Left behind-Prevention via in Cabin CO2 Sensing
- 2020
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Ingår i: SAE technical paper series. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191. ; :April
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Tidskriftsartikel (refereegranskat)abstract
- Can one technical solution help prevent drowsy drivers and detect a child left behind? Yes, using a single, maintenance-free, Non-Dispersive Infrared (NDIR) gas sensor integrated in the cabin ventilation system. Carbon dioxide (CO2) is an established proxy for ventilation needs in buildings. Recently, several studies have been published showing a moderate elevation of the indoor carbon dioxide level effect cognitive performance such as information usage, activity, focus and crisis response. A study of airplane pilots using 3-hour flight simulation tests, showed pilots made 50% more mistakes when exposed to 2,500 ppm carbon dioxide compared to 700 ppm. This has a direct impact on safety. All living animals and humans exhale carbon dioxide. In our investigations we have found that an unintentionally left behind child, or pet, can easily be detected in a parked car by analyzing the carbon dioxide trends in the cabin. Even an 8-month old baby acts as a carbon dioxide source, increasing cabin CO2 levels at a 20ppm/minute rate allowing for detection within one minute. Vehicles running with the ventilation system in recirculation mode normally reach above the fresh air limit of 1,000 ppm within a few minutes. The carbon dioxide level normally stabilizes between 3,000 and 10,000 ppm. Levels that will make the driver drowsy, reducing their cognitive performance and impact safety. Using an NDIR gas sensor in the ventilation system will reduce driver performance degradation due to elevated carbon dioxide levels, allowing reliable detection of any unintentionally left behind children or pets, potentially saving lives. © 2020 SAE International. All Rights Reserved.
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| 2. |
- Stierle, A., et al.
(författare)
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Real time observation of ultrathin epitaxial oxide growth during alloy oxidation
- 2007
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 9, s. 331-331
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the thermal oxidation of the intermetallic alloy CoGa in situ, in real time on the atomic scale, during the growth of an ultrathin, epitaxial Ga oxide layer. On the basis of an extended set of surface x-ray diffraction data, density functional theory calculations and core level spectroscopy data, we find that the oxide film consists of an oxygen ion double layer, which contains the basic building block of bulk beta- Ga2O3. The oxide formation takes place via the nucleation of two- dimensional, anisotropic oxide islands which laterally grow and coalesce. A dramatic increase of the oxide island size is observed for low O-2 pressures in the 10(-8) mbar regime, which we interpret as the onset of a step flow like growth mode. This allows us to conclude that thermal oxidation can be considered as a hetero- epitaxial growth process, that follows similar atomistic growth principles to molecular beam epitaxy. As a consequence, the structural perfection of the oxide layer can be tailored by the appropriate choice of oxygen pressure and temperature.
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