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Miriam A Ashleyross - One of the best experts on this subject based on the ideXlab platform.

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

Brad A Chadwell - One of the best experts on this subject based on the ideXlab platform.

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

George V Lauder - One of the best experts on this subject based on the ideXlab platform.

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

Emily M Standen - One of the best experts on this subject based on the ideXlab platform.

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

  • median fin function during the escape response of bluegill sunfish lepomis macrochirus ii fin ray curvature
    The Journal of Experimental Biology, 2012
    Co-Authors: Brad A Chadwell, Emily M Standen, George V Lauder, Miriam A Ashleyross
    Abstract:

    Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish ( Lepomis macrochirus ), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces. * LIST OF SYMBOLS AND ABBREVIATIONS : ARy# : anal ray, where # indicates its numbered position within the fin ASp# : anal spine, where # indicates its numbered position within the fin C : chord axis of the fin surface, perpendicular to the span axis cT : tangent to the chordwise curve DRy# : dorsal ray, where # indicates its numbered position within the fin DSp# : dorsal spine, where # indicates its numbered position within the fin EMG : electromyography L : lateral axis, normal to the fin surface Mid : middle trunk r : fin-ray identifier S : span axis of the fin surface S1 : stage 1 of the C-start S2 : stage 2 of the C-start sB : binormal to the fin surface sfA : soft region of the anal fin sfD : soft dorsal fin ssCOM : stretched-straight center of mass sT : tangent to the spanwise curve t : time point during a C-start sequence T : time zero tr : directional transition event, i.e. change in direction of rotation or orientation t X : time of a Given Parameter, where X is the event of a Given Parameter Δ t X : time difference between a Given fin-ray Parameter and its corresponding axial event, where X is the event of a Given Parameter κchord : chordwise curvature, perpendicular to the fin surface and span axis κspan : spanwise curvature, perpendicular to the fin surface ϕ′ : turning rate, i.e. the first time derivative of yaw

Vladimir Dyakonov - One of the best experts on this subject based on the ideXlab platform.

  • influence of charge carrier mobility on the performance of organic solar cells
    Physica Status Solidi-rapid Research Letters, 2008
    Co-Authors: Carsten Deibel, Alexander Wagenpfahl, Vladimir Dyakonov
    Abstract:

    The power conversion efficiency of organic solar cells based on donor–acceptor blends is governed by an interplay of polaron pair dissociation and bimolecular polaron recombination. Both processes are strongly dependent on the charge carrier mobility, the dissociation increasing with faster charge transport, with raised recombination losses at the same time. Using a macroscopic effective medium simulation, we calculate the optimum charge carrier mobility for the highest power conversion efficiency, for the first time accounting for injection barriers and a reduced Langevin-type recombination. An enhancement of the charge carrier mobility from 10–8 m2/V s for state of the art polymer–fullerene solar cells to about 10–6 m2/V s, which yields the maximum efficiency, corresponds to an improvement of only about 20% for the Given Parameter set. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  • influence of charge carrier mobility on the performance of organic solar cells
    arXiv: Materials Science, 2008
    Co-Authors: Carsten Deibel, Alexander Wagenpfahl, Vladimir Dyakonov
    Abstract:

    The power conversion efficiency of organic solar cells based on donor--acceptor blends is governed by an interplay of polaron pair dissociation and bimolecular polaron recombination. Both processes are strongly dependent on the charge carrier mobility, the dissociation increasing with faster charge transport, with raised recombination losses at the same time. Using a macroscopic effective medium simulation, we calculate the optimum charge carrier mobility for the highest power conversion efficiency, for the first time accounting for injection barriers and a reduced Langevin-type recombination. An enhancement of the charge carrier mobility from $10^{-8}$m$^2$/Vs for state of the art polymer:fullerene solar cells to about $10^{-6}$m$^2$/Vs, which yields the maximum efficiency, corresponds to an improvement of only about 20% for the Given Parameter set.