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| 2. |
- Hedenström, Anders, et al.
(författare)
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Bat flight generates complex aerodynamic tracks
- 2007
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 316:5826, s. 894-897
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Tidskriftsartikel (refereegranskat)abstract
- The flapping flight of animals generates an aerodynamic footprint as a time-varying vortex wake in which the rate of momentum change represents the aerodynamic force. We showed that the wakes of a small bat species differ from those of birds in some important respects. In our bats, each wing generated its own vortex loop. Also, at moderate and high flight speeds, the circulation on the outer ( hand) wing and the arm wing differed in sign during the upstroke, resulting in negative lift on the hand wing and positive lift on the arm wing. Our interpretations of the unsteady aerodynamic performance and function of membranous-winged, flapping flight should change modeling strategies for the study of equivalent natural and engineered flying devices.
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| 3. |
- Hedenström, Anders, et al.
(författare)
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High-speed stereo DPIV measurement of wakes of two bat species flying freely in a wind tunnel
- 2009
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Ingår i: Experiments in Fluids. - : Springer Science and Business Media LLC. - 1432-1114 .- 0723-4864. ; 46:5, s. 923-932
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies on wake flow visualization of live animals using DPIV have typically used low repetition rate lasers and 2D imaging. Repetition rates of around 10 Hz allow similar to 1 image per wingbeat in small birds and bats, and even fewer in insects. To accumulate data representing an entire wingbeat therefore requires the stitching-together of images captured from different wingbeats, and at different locations along the wing span for 3D-construction of wake topologies. A 200 Hz stereo DPIV system has recently been installed in the Lund University wind tunnel facility and the high-frame rate can be used to calculate all three velocity components in a cube, whose third dimension is constructed using the Taylor hypothesis. We studied two bat species differing in body size, Glossophaga soricina and Leptonycteris curasoa. Both species shed a tip vortex during the downstroke that was present well into the upstroke, and a vortex of opposite sign to the tip vortex was shed from the wing root. At the transition between upstroke/downstroke, a vortex loop was shed from each wing, inducing an upwash. Vorticity iso-surfaces confirmed the overall wake topology derived in a previous study. The measured dimensionless circulation, I"/Uc, which is proportional to a wing section lift coefficient, suggests that unsteady phenomena play a role in the aerodynamics of both species.
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| 5. |
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| 7. |
- Johansson, Christoffer, et al.
(författare)
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The near and far wake of Pallas' long tongued bat (Glossophaga soricina).
- 2008
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 1477-9145 .- 0022-0949. ; 211:Pt 18, s. 2909-2918
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Tidskriftsartikel (refereegranskat)abstract
- The wake structures of a bat in flight have a number of characteristics not associated with any of the bird species studied to this point. Unique features include discrete vortex rings generating negative lift at the end of the upstroke at medium and high speeds, each wing generating its own vortex loop, and a systematic variation in the circulation of the start and stop vortices along the wingspan, with increasing strength towards the wing tips. Here we analyse in further detail some previously published data from quantitative measurements of the wake behind a small bat species flying at speeds ranging from 1.5 to 7 m s(-1) in a wind tunnel. The data are extended to include both near- and far-wake measurements. The near-/far-wake comparisons show that although the measured peak vorticity of the start and stop vortices decreases with increasing downstream distance from the wing, the total circulation remains approximately constant. As the wake evolves, the diffuse stop vortex shed at the inner wing forms a more concentrated vortex in the far wake. Taken together, the results show that studying the far wake, which has been the standard procedure, nevertheless risks missing details of the wake. Although study of the far wake alone can lead to the misinterpretation of the wake topology, the net, overall circulation of the main wake vortices can be preserved so that approximate momentum balance calculations are not unreasonable within the inevitably large experimental uncertainties.
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| 8. |
- Kampfer, P, et al.
(författare)
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Cohnella thermotolerans gen. nov., sp nov., and classification of 'Paenibacillus hongkongensis' as Cohnella hongkongensis sp nov.
- 2006
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Ingår i: INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY. - : Microbiology Society. - 1466-5026 .- 1466-5034. ; 56, s. 781-786
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Tidskriftsartikel (refereegranskat)abstract
- A Gram-positive, rod-shaped, endospore-forming organism, strain CCUG 47242T, was isolated from a sample of industrial starch production in Sweden. 16S rRNA gene sequence analysis demonstrated that this isolate was moderately related to species of the genus Paenibacillus, with <94·4 % sequence similarity to all other hitherto described Paenibacillus species. Strain CCUG 47242T showed the greatest sequence similarity (96·5 %) to ‘Paenibacillus hongkongensis’ HKU3, a strain with a name that has not yet been validly published. Chemotaxonomic data [major menaquinone, MK-7 (98 %); major polar lipids, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, lysyl-phosphatidylglycerol, two unknown phospholipids, four unknown aminophospholipids; major fatty acids, iso-C16 : 0 and anteiso-C15 : 0] showed some significant differences when compared with the type species of the genus Paenibacillus, Paenibacillus polymyxa. Physiological and biochemical tests allowed clear phenotypic differentiation of strain CCUG 47242T from strain HKU3. On the basis of 16S rRNA gene sequence analysis, in combination with chemotaxonomic data, strains CCUG 47242T and HKU3 represent two novel species of a new genus of endospore-forming bacteria for which we propose the names Cohnella thermotolerans gen. nov., sp. nov. (type strain CCUG 47242T=CIP 108492T=DSM 17683T) and Cohnella hongkongensis sp. nov. (type strain HKU3T=CCUG 49571T=CIP 107898T=DSM 17642T).
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| 9. |
- Kämpfer, P, et al.
(författare)
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Undibacterium pigrum gen. nov., sp. nov., isolated from drinking water
- 2007
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Ingår i: International Journal of Systematic and Evolutionary Microbiology. - : Microbiology Society. - 1466-5026 .- 1466-5034. ; 57:7, s. 1510-1515
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Tidskriftsartikel (refereegranskat)abstract
- Two Gram-negative, rod-shaped, oxidase-positive, non-spore-forming, non-motile bacteria (strains CCUG 49009T and CCUG 49012), both isolated from drinking water, were characterized. On the basis of chemotaxonomic data [major ubiquinone, Q-8; predominant polyamines, putrescine and 2-hydroxyputrescine; major polar lipids, phosphatidylethanolamine, moderate amounts of diphosphatidylglycerol and phosphatidylglycerol and minor amounts of three aminolipids and phosphatidylserine; major fatty acids, C16:0 and summed feature 3 (C16:1ω7c/C15:0 iso 2-OH)] and 16S rRNA gene sequence similarities, both strains clearly belong to the family Oxalobacteraceae of the Betaproteobacteria. 16S rRNA gene sequence similarities with members of the most closely related genera of this group (Herminiimonas, Massilia, Duganella, Telluria, Herbaspirillum, Janthinobacterium, Naxibacter and Paucimonas) were less than 96.5% for both strains. The two strains also shared a relatively low 16S rRNA gene sequence similarity (96.8%). Although phylogenetic analysis based on 16S rRNA gene sequence similarities clearly showed that the two organisms formed a separate branch, their phenotypes (including chemotaxonomic features) were hardly distinguishable and showed high similarities to those reported for the most closely related genera. On the basis of DNA–DNA hybridization results, the two strains were shown to represent separate species (sharing only 20% DNA–DNA relatedness), but they could not be clearly differentiated phenotypically from each other. It is evident that these organisms represent a new genus, Undibacterium gen. nov., with one species, Undibacterium pigrum sp. nov. The type strain of Undibacterium pigrum is strain CCUG 49009T (=CIP 109318T). Strain CCUG 49012 (=CIP 108976) probably represents a second species of this genus, but is described here as a second genomovar of this species because of the lack of differentiating characters.
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| 10. |
- Weigelt, Sigrid, et al.
(författare)
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Formation of trioctylamine from octylamine on Au(111)
- 2008
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 130:16, s. 5388-5388
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of octylamine on Au(111) under ultrahigh vacuum conditions is investigated. The molecules surprisingly undergo a thermally activated chemical reaction, resulting in formation of trioctylamine as confirmed both by X-ray photoelectron spectroscopy (XPS) and by comparison to the scanning tunneling microscopy (STM) signature of trioctylamine deposited directly onto the surface.
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