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dc.contributor.authorMagnanelli, Elisa
dc.contributor.authorWilhelmsen, Øivind
dc.contributor.authorAcquarone, Mario
dc.contributor.authorFolkow, Lars
dc.contributor.authorKjelstrup, Signe
dc.date.accessioned2017-03-17T12:54:35Z
dc.date.available2017-03-17T12:54:35Z
dc.date.issued2016-07-14
dc.description.abstractReindeer in the arctic region live under very harsh conditions and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating fur, the reindeer nasal mechanism for heat and mass exchange during respiration plays a fundamental role. We present a dynamic model to describe the heat and mass transport that takes place inside the reindeer nose, where we account for the complicated geometrical structure of the subsystems that are part of the nose. The model correctly captures the trend in experimental data for the temperature, heat and water recovery in the reindeer nose during respiration. As a reference case, we model a nose with a simple cylindrical-like geometry, where the total volume and contact area are the same as those determined in the reindeer nose. A comparison of the reindeer nose with the reference case shows that the nose geometry has a large influence on the velocity, temperature and water content of the air inside the nose. For all investigated cases, we find that the total entropy production during a breathing cycle is lower for the reindeer nose than for the reference case. The same trend is observed for the total energy consumption. The reduction in the total entropy production caused by the complicated geometry is higher (up to -20 %) at more extreme ambient conditions, when energy efficiency is presumably more important for the maintenance of energy balance in the animal. In the literature, a hypothesis has been proposed, which states that the most energy-efficient design of a system is characterized by equipartition of the entropy production. In agreement with this hypothesis, we find that the local entropy production during a breathing cycle is significantly more uniform for the reindeer nose than for the reference case. This suggests that natural selection has favored designs that give uniform entropy production when energy efficiency is an issue. Animals living in the harsh arctic climate, such as the reindeer, can therefore serve as inspiration for a novel industrial design with increased efficiency.en_US
dc.description.sponsorshipThe project is funded by VISTA – a basic research program in collaboration between The Norwegian Academy of Science and Letters, and Statoil – and by the Tromsø Research Foundation.en_US
dc.descriptionSource: <a href=http://dx.doi.org/10.1515/jnet-2016-0038>doi: 10.1515/jnet-2016-0038</a>en_US
dc.identifier.citationMagnanelli E, Wilhelmsen Ø, Acquarone M, Folkow P., Kjelstrup S. The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration. Journal of Non-Equilibrium Thermodynamics. Volume 42, Issue 1, Pages 59–78, ISSN (Online) 1437-4358, ISSN (Print) 0340-0204, DOI: https://doi.org/10.1515/jnet-2016-0038, July 2016en_US
dc.identifier.cristinIDFRIDAID 1382869
dc.identifier.doi10.1515/jnet-2016-0038
dc.identifier.issn0340-0204
dc.identifier.issn1437-4358
dc.identifier.urihttps://hdl.handle.net/10037/10767
dc.language.isoengen_US
dc.publisherDe Gruyteren_US
dc.relation.journalJournal of Non-Equilibrium Thermodynamics
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400en_US
dc.subjectVDP::Mathematics and natural science: 400en_US
dc.titleThe Nasal Geometry of the Reindeer Gives Energy-Efficient Respirationen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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